Stem Cells International

Stem Cells International / 2015 / Article
Special Issue

Stem Cell Differentiation and Therapeutic Use

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Review Article | Open Access

Volume 2015 |Article ID 734731 | 19 pages |

Stem Cells and Regenerative Medicine: Myth or Reality of the 21th Century

Academic Editor: Juan Carlos Casar
Received26 Dec 2014
Revised22 Apr 2015
Accepted24 May 2015
Published02 Aug 2015


Since the 1960s and the therapeutic use of hematopoietic stem cells of bone marrow origin, there has been an increasing interest in the study of undifferentiated progenitors that have the ability to proliferate and differentiate into various tissues. Stem cells (SC) with different potency can be isolated and characterised. Despite the promise of embryonic stem cells, in many cases, adult or even fetal stem cells provide a more interesting approach for clinical applications. It is undeniable that mesenchymal stem cells (MSC) from bone marrow, adipose tissue, or Wharton’s Jelly are of potential interest for clinical applications in regenerative medicine because they are easily available without ethical problems for their uses. During the last 10 years, these multipotent cells have generated considerable interest and have particularly been shown to escape to allogeneic immune response and be capable of immunomodulatory activity. These properties may be of a great interest for regenerative medicine. Different clinical applications are under study (cardiac insufficiency, atherosclerosis, stroke, bone and cartilage deterioration, diabetes, urology, liver, ophthalmology, and organ’s reconstruction). This review focuses mainly on tissue and organ regeneration using SC and in particular MSC.

1. Introduction

Most of human tissues and organs do not regenerate spontaneously, justifying why cell therapy is today a significant tissue and organ repair strategy. The concept of regenerative medicine is an emerging multidisciplinary field to revolutionize the way “to improve the health and quality of life by restoring, maintaining or enhancing tissue and functions of organs.

The history of SC began in the mid nineteenth century with the discovery that some cells could generate other cells. In the beginning of the 20th century, SC were discovered when it was found that the bone marrow contained hematopoietic SC and stromal cells [1, 2]. The first successful transplant was performed by Dr. Thomas in Cooperstown, NY, in the late 1950s. The transplant involved identical twins, one of whom had leukemia, avoiding the problems associated with nontwin transplants, such as graft-versus-host disease [3]. It was not until 1968 that the first successful nontwin (allogeneic) transplant was performed. In this case, the donor was a sibling of the patient [4]. The first successful unrelated donor transplant took place in 1973 in New York when a young boy with a genetic immunodeficiency disorder received multiple marrow transplants from a donor identified as a match through a blood bank in Denmark. The first successful unrelated donor transplant for a patient with leukemia took place in 1979 at the Hutchinson Center. Since then, bone marrow transplantation expanded rapidly during the 1990s [5].

In 1998, cells from the inner cell mass of early embryos were isolated as the first embryonic stem cell lines [6, 7]. Later, in 2006, Takahashi et al. described the IPS (induced pluripotent stem cells) [810]. Several categories of stem cells can be used in regenerative medicine including embryonic stem cells (ESC), fetal stem cells (FSC), and adult stem cells (ASC) [11, 12]. Not all stem cells are of equal interest in terms of ability for clinical applications and are able to evolve into different specialized cells. Fetal and adult stem cells are undifferentiated cells, which can be found within fetus or in adult tissues or organs. They are able of limited self-renewal and are multipotent, which means that they can differentiate in several types of tissue cells. Although adult stem cells cannot be expanded in culture indefinitely, the use of these cells does not present ethical problems.

Multipotent SC, self-renewing, and adherent MSC, represent a small fraction of the marrow stroma [1321]. These nonhematopoietic stromal cells are usually harvested in vitro from bone marrow but also from other tissues of mesodermal origin: fetal or neonatal tissues (umbilical cords or placenta), adipose tissue, joint synovium, dental pulp, and so forth [2230]. MSC are characterized by their capacity of self-renewal and differentiation in different cells types (chondrocytes, endothelial cells,…). They were initially identified as progenitors able to produce colonies of fibroblast-like cells (CFU-F for colony forming units-fibroblast), to differentiate into bone or cartilaginous tissues, and to support hematopoiesis. Indeed, MSC cultivated under adapted conditions differentiate into cells of conjunctive tissues: osteoblasts, chondrocytes, tenocytes, adipocytes, and stromal cells supporting the hematopoiesis [31]. They can also differentiate into vascular smooth muscle cells, sarcomere muscular cells (skeletal and cardiac), and endothelial cells [3236]. Recent publications even state that they can differentiate into nonmesodermal cells such as hepatocytes, neurons, or astrocytes [3742].

MSC do not have a defined profile of surface antigen expression but there are available markers to identify them. They are mainly characterized by the expression of different antigens, CD105, CD73, CD90, Stro-1, CD49a, CD29, and CD166. On the other hand, MSC do not express antigens CD34 and CD45 (specific of the cells of hematopoietic origin), glycophorin (specific of blood cells), antigens of differentiation of the various leucocyte populations (CD14, CD33, CD3, and CD19), and HLA-DR [4346]. The International Society for Cellular Therapy suggested a consensual definition: cells must adhere on plastic, express CD75, CD90, and CD105 and not CD34, CD45, HLA-DR, or CD11b, CD19, and are capable of differentiation into chondrocytes, osteoblasts, and adipocytes [26, 47]. Under current conditions of in vitro culture [48], the results obtained showed that the proliferation of MSC remained within the limit of Hayflick of 40 in vitro population doublings but was affected by the age of the donors [4954]. Recent studies show that the ability of expansion and differentiation of MSC is donor-dependent. It seems that the number of MSC and their ability of in vitro differentiation and tissue regeneration in vivo decrease with age and according to the donor pathology [55]. They generally do not circulate in the peripheral blood but are resident in mesenchymal tissues [56]. Bone marrow mesenchymal stem cells (BM-MSC) can provide a support for the growth of the hematopoietic stem cells through the secretion of cytokines and through the creation of cellular interactions either directly (adhesion molecules) or indirectly (production of the extracellular matrix components). Today, nonstandardized protocols exist for their culture, differentiation, and self-renewal ability. In addition, some MSC could be more immature, without any tissue specialization, and their existence has been suspected in human [5759].

IPS result in the acquisition of a novel state followed by the in vitro reprogramming of an adult cell after addition of selected transcription factors. The major advance in this field was performed in 2006 with the possibility of a direct reprogramming of somatic cells into pluripotent cells starting from fibroblasts [8, 9]. Generation of IPS depends on the genes used for the induction (Oct 3-4 and Sox gene family are determinant regulators for the induction process). In the course of the reprogramming, an extinction of the characteristic genes of the fibroblast, a reexpression of embryonic genes (SSEA 1 and 4), and activation of telomerase are observed. However, the efficiency of the technique is low. It is likewise necessary to underline that the IPS are exposed to a significant risk of malignant transformation due to the presence of the oncogene c-Myc used in the reprogramming. The present interest of this type of lines and its nonembryonic origin is the possibility of establishing specific lines of deficient patients for clinical research. The IPS are thus a tool for the study of the mechanisms of cell differentiation and genetic diseases and also for pharmacological screening [60].

2. Main Clinical Applications of Stem Cells

The majority of medicine specialities and different applications can benefit in the next decade from the progress in regenerative medicine: most are at experimental stages, with the exception of bone marrow transplantation. Cell therapy covers very large potentials in many clinical fields in cancer and in regenerative medicine [6163], and more than 3,000 trials with SC are currently in progress (

Nevertheless, before SC therapeutics can be applied in the clinic, more research is necessary to understand their behaviour upon transplantation as well as the mechanisms of their interaction with the diseased microenvironment. Many authors underlined that regenerative medicine is likely to transform in the future the way we practice medicine, using pharmacological or surgical procedures. The mechanism of action of SC is still being determined. The general consensus today suggests that the most probable mechanism may be through the release of cytokines and other growth-promoting factors.

Before clinical applications, many challenges are to be solved [64].(i)How to differentiate SC to the desired cell phenotype and which biological and environmental parameters are important during culture for differentiation?(ii)What are the best suitable cells: which precursors or differentiated cells?(iii)What are the possible immunological barriers when allogenic cells are used?(iv)What are the best biomarkers to identify pluripotent/multipotent/precursors cells?(v)What is the role of the microenvironment (scaffolds, mechanical signals)? [65](vi)What are the bioreactive molecules such as cytokines or growth factors that can support the formation of the desired tissue?(vii)Are there potential karyotype changes during cell culture?(viii)The translation from laboratory to clinics by using good laboratory practice (GPL) could impact on cell properties?(ix)Which are the best methods to trace cells in vivo?

It is important to note that clinical applications of biotherapies are strongly controlled in Western countries. Harvesting cells or tissues of human origin can only be performed in health centers accredited by Public Authorities (in France, different regulation laws describe the procedure of authorization related to preparation, storage, and clinical use of cells and tissues). The European Regulating Authorities are also very strict about the nature of the clinical trials and about the choice of the patients. Before grafting, different points must be precised.(i)The severity degree of the pathology has to be considered.(ii)What type of grafting is planned for the patients?(iii)The site of grafting should be defined.(iv)What is the benefit for the patient?(v)What is the clinical evaluation method to investigate the functionality of the graft?(vi)Possible side effects.

2.1. Stem Cells and Cancer

Cancer SC has been for long a concept of hematology, particularly in acute myeloid leukaemia. However, more recently, research studies have described the concept of tumor initiating cells in solid tumors [6672]. The anticancer cell therapy includes bone marrow grafting and in particular the injection of autologous or allogenic hematopoietic stem cells (HSC) CD34+. This population (CD34+) is however heterogeneous regarding its ability to generate the various lines and is the object of many research studies [73]. The graft of HSC has gained an essential place in therapeutic oncohematology [74, 75]. By 1950s, the fundamental role of hematopoietic tissue in protection against radiations was highlighted. The first clinical trials in 1959 showed the feasibility of an engraftment of allogenic marrow [3]. In 1968, the first compatible allogenic grafts HLA were successfully carried out among patients presenting severe combined deficits [4]. Then, the first cryopreserved autografts of bone marrow were reported in lymphomas. Since then, studies were pursued to improve the clinical trials and to decrease, in autologous situations, the relapses linked to the residual disease often present in the graft. Other studies aimed to prevent, in allogenic situations, the graft versus host disease [76].

Using chemical agents or specific monoclonal antibodies, ex vivo manipulations of grafts were developed to eliminate tumoral cells or T lymphocytes. By 1984, new sources of HSC have been highlighted in the peripheral and placental blood [77, 78]. That is a major step toward the development of grafts of blood HSC. The first placental blood graft was performed by Gluckman in Paris in 1998 [79]. Since 1993, banks of cryopreserved grafts of placental origin have been developed [8082].

The use of cytotoxic T cells or NK cells, isolated and amplified in vitro, can be proposed for anticancer applications [8387]. The use of B cells, CD4+ T cells, regulatory T cells [88, 89], and myeloid dendritic or predendritic cells producing interferon is also possible. The injection of dendritic cells for antitumoral immunization, mainly in the residual disease, but also as adjuvant therapy, is the basis of different clinical trials. However, much remains to be understood as the cells nature, their capacity to homing to specific sites (tumor, nodes), and their capacity to stimulate the immune system.

Several clinical trials have been proposed (34 in the beginning of 2014). The main applications are MSC and graft failure, graft versus host disease, and treatment of myelodysplasia [90, 91]. This point will not be developed in this review but a lot of information can be found in the literature [9294].

2.2. Stem Cells and Tissue Regeneration

Regenerative medicine, based on the graft of tissue native cells (i.e., myocytes, chondrocytes, etc.) or SC able to differentiate into somatic cells, holds great promise if clinical hurdles can be overcome, particularly their possible tumorigenic property. This was highlighted in a case report involving a child who received fetal neural SC as a treatment for a neurodegenerative disease, but who later unfortunately developed multifocal glioneuronal tumor from transplanted neural stem cells [95]. Many studies have been published in this area in the last 20 years [96100].

The regeneration of damaged tissues or organs implies the existence of cells able to proliferate, differentiate, and give a functional contribution to the regenerative processes. Among the possible middle-term therapeutic applications, cardiac insufficiency, atherosclerosis, osteoarticular diseases, diabetes, and liver diseases can be considered.

In regenerative medicine, four important issues have to be taken into account: (1) the choice of the reparative cells that can form a functional tissue; (2) if necessary, the choice of appropriate scaffolds for transplantation; (3) the role of bioreactive molecules, such as cytokines and growth factors that support the formation of the desired tissue; (4) grafting and safety studies (GMP compliance). More than 3,000 clinical trials are indexed in “” (mainly in USA (25%), Europe (30%), and Asia (40%)), with most of them using MSC.

2.2.1. Heart Disease

Every year in France, 10,000 new cases of serious cardiac insufficiency are detected. Heart transplants remain the only treatment for the most advanced stages but the shortage of donors and complications of immunosuppression restrict the indications. Surgical remodeling of the left ventricle only deals with the particular anatomical forms and recent negative results have led to a review of the indications. Mechanical ventricular assistance remains a temporary solution for those waiting for a transplant. There is thus a need for new treatment solutions. Xenotransplantation is not progressing since the immunological challenges are considerable and there are major safety considerations. Gene therapy and IPS are still in their infancy [27, 101] and the complexity of the mechanisms involved in heart failure does not lend itself to this therapeutic approach. Finally, cell therapy has a place, but only in patients who retain a sufficient reserve of contractile cells. The numerous trials have not made it possible to reach a conclusion at the present time [102109].

Today more than 40 clinical trials are listed with a majority of bone marrow, Wharton’s jelly and adipose stem cells [110113]. Histologic observations in autopsy of samples of allogenic cardiac grafts in sex mismatch showed the formation of cardiomyocytes with the receiver genotype in the myocardial tissue coming from the donor [50]. Y genotype cardiomyocytes have been shown in the myocardium of female mice that received an intravenous injection of bone marrow coming from male mice. Isotypic studies showed the homing of progenitor stem cells from bone marrow towards the lesion sites after a coronary ligation. The molecular signals leading to tissue repair are unknown. However some cytokines released during cardiac ischemia could be involved.

The treatment of myocardial infarction (MI), however, is subject to a significant constraint: the immediate availability of cells. The intracoronary injection of stem cells prepared starting from a withdrawal of bone marrow did not lead to significant improvements (3% maximum of the ejection fraction of the left ventricle). In the same manner, the intravenous injection of MSC does not give significant results. In the case of heart failure, the cell therapy turns out to be no efficient and it seems difficult today to envisage a regenerative therapy. At the end of 2007, the US based stem cell company Osiris Therapeutics completed a human trial using allogeneic SC for the treatment for heart disease. An intravenous drip was used to deliver of the shelf MSC to patients that had recently suffered a heart attack. No deaths occurred, and the treatment is now widely thought as safe [109].

Today there is no regulatory approved cell treatment for myocardial infarction, but research and clinical studies offer the hope for successful cell therapy in the next decades.

2.2.2. Peripheral Arterial Disease

Lower limb ischemia causes a decreased blood flow in the lower leg with intense pain and swelling [114]. Recently, preliminary results of a Phase I clinical trial using adult SC treatment for severe limb ischemia was presented with endothelial progenitor cells (EPC) and MSC. The cells, obtained by bone marrow aspiration, were mixed and infused into damaged vessels. According to this study, there were no adverse effects as a result of the infusions. More importantly, their patients experienced a progressive and lasting improvement in clinical parameters including walking tests, oxygen pressure, angiography, and quality of life. The use of adult SC therapy in ischemia patients would allow the development of new mature and stable capillaries. These cells have shown the property of differentiation into endothelial or smooth muscle cells but also produce a significant amount of vascular growth factors [115120].

Harvest Technologies Corp. (MA, USA) presented some positive results from a 30-patient clinical trial of a stem cell-based treatment of critical limb ischemia (CLI). Clinical evaluation of the patients with thromboangiitis obliterans disease conducted for 12 weeks showed that the treatment had significant clinical effect. The most important finding was that more than 85% of patients were able to save their legs. Other major endpoints also showed significant improvement including quality of life assessment and individual perception of pain; there was 100% reduction in the use of pain medications. Limb perfusion, as measured by TcPO2, also showed statistically significant improvement. Thirty-three percent of the patients had serious ulcers and 90% of these showed 90% or better wound closure in 26 weeks. There were no adverse events associated with the treatment.

In 2009 Pluristem Therapeutics Inc. (Haifa, Israel) began a Phase I clinical trial with a placenta-derived SC product for the treatment of CLI (end-stage of peripheral artery disease). The different trials (12 patients) generally evaluated the safety of the product in patients with CLI.

2.2.3. Ischemia Stroke

Cerebral infarct is a process, in which brain damage increases with time. Therefore the time when treatment is started is critical. At present, the only effective treatment (tissue plasminogen activator) has to be administrated very soon after the stroke [114]. In animal models, intravenous administration of hUCB cells to rats, after induction of stroke by occlusion of the middle cerebral artery, promoted the improvement of neurological function. The cells were mainly found in the cortex and the striatum of the damaged hemisphere and outside the brain, in bone marrow and spleen, and in very small amounts in muscle, heart, lungs, and liver. These authors found that some of the injected cells showed neuronal markers (NeuN2 and MAP2), astrocytic markers (GFAP), and endothelial cell markers (FVIII) [121].

Actually, IPS cells should be ideally generated without using viral vectors and without teratoma formation for being suitable for clinical use. But today the main clinical trials in topic use autologous bone marrow MSC [122124].

2.2.4. Nervous System and Neurodegenerative Diseases

The classical notion of a renewal of adult neuronal cells is today questioned, but the therapeutic applications still remain uncertain. The spinal cord repair is currently the purpose of a great deal of work after injury [125, 126] (10 trials) with bone marrow SC. In 2010, a first study from cells derived from embryo SC producing oligodendrocytes was carried out in a volunteer in connection with the GERON Company [127, 128]. So far, no information has been given on the result of the test and the study seems to have been stopped. In France, one group is involved in a clinical study, in cooperation with a German team, using autologous bone marrow SC. Other studies should also begin in USA, Portugal, and China.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterised by a progressive muscle weakness that can result in paralysis and death. The multicausality of neuron death poses a considerable problem to the development of new therapeutic strategies, including cell therapy. Numerous hypotheses have been developed about the origin of ALS, but it seems that the immune system may be involved. Cell transplantation approaches in ALS remain to generate a neuroprotective environment for degenerating motor neurons by transplantation of nonneuronal cells, rather than to replace lost motor neurons. Among the cell therapy approaches tested in motor neuron disease animal models, systemic injection of human cord blood mononuclear cells has proven to reproducibly increase the life span of SOD1G93A mice, a model of familial ALS, even if only few transplanted cells were found in the damaged areas. Bigini et al. showed that human cord blood (mononuclear cells) significantly enhanced symptoms progression and prolonged survival in SOD1G93A mice and were localized in the lateral ventricles, even 4 months after administration [129]. However, hCB-MNCs were not found in the spinal cord. These results strengthen the hypothesis that the beneficial role of transplanted cells is not due to cell replacement but is rather associated with the production and release of circulating protective factors. They observed in this study that hCB-MNCs release a series of cytokines and chemokines with anti-inflammatory properties that could be responsible of the functional improvement of mouse models of motor neuron degenerative disorders. The clinical trials (25 beginning of 2014) are mainly focused on Parkinson [130] and Alzheimer [131] diseases and amyotrophic lateral sclerosis [132] with bone marrow and umbilical cord SC.

2.2.5. Bone and Cartilage [133135]

The prevalence of osteoarthritis and degenerative joint disease will increase in the near future, driving the market for SC therapies for joints and cartilage [136]. In fact, most of the pioneering work using stem cells for bone and tendon repair was carried out in the veterinary field, mainly injuries in racehorses. Adult MSC are able to differentiate in bone, cartilage, tendon, ligament, and muscle. Today the most studied source for bone and cartilage is the bone marrow with different scaffolds. For bone the problem is more complex, when compared to cartilage, because bone is a vascularized tissue and the formation of mineralized bone matrix is not sufficient to lead to a functional tissue [137139].

Cartilage is a mesenchymal tissue composed of one cell-type (chondrocytes), extracellular matrix (ECM), and water. Chondrocytes represent only 1-2% of cartilage volume. The cartilage ECM is composed of collagen fibers (mainly type II collagen) supporting glycoproteins and proteoglycans which have a protein core associated with glycosaminoglycan molecules such as hyaluronic acid (HA) and chondroitin sulfate. The tissue fluid, mainly water, contributes to the particular mechanical properties of cartilage and provides nutrition and exchange with synovial fluid and with extracellular fluid or other adjacent tissues. Hyaline cartilage functions with minimal friction. It demonstrates an excellent ability to provide and adaptation to compression and distributes loads on the surface of the joint [140, 141].

Because of the limited self-healing capacity of cartilage, repair of articular defects caused by degenerative joint diseases or traumatic injuries represents an open challenge and current therapies for cartilage repair are inadequate for restoring form and function [142144]. In vitro preparation of functionally developed biocartilage substitutes is an attractive concept for future clinical treatments of cartilage injuries and degeneration. Today a FDA approved cellular-based therapy for cartilage defects uses chondrocytes [145]. In this application, autologous cells are harvested from a biopsy and expanded ex vivo to obtain a large number of cells for transplantation. Autologous expanded chondrocytes have a low risk of immune rejection but they have a tendency to dedifferentiate (loss of phenotype) in vitro. In other words, the influence of mechanical forces on cell function in vitro has been demonstrated for engineering cartilage and bones [146]. In cartilage production, dynamic mechanical stresses on chondrocytes and MSC promote differentiation and increase matrix production [147149].

Many clinical studies performed have demonstrated the therapeutic potentials of MSC from bone marrow or adipocytes [150153]. Wharton’s jelly MSC offer another source that has proven a chondrogenic differentiation potential and could be used in an allogenic context [46, 154156].

While MSC therapy is promising, the incomplete understanding of their biological characteristics and function limits today the utilization of MSC in clinical application [157]. Role of growth factors, cytokines, receptors, transmembrane signalling, and adhesive proteins in MSC interactions are still elusive. In a study of the effects of MSC in a caprine model of traumatic osteoarthritis it was showed that intra-articular delivery of autologous cells to meniscectomized joints resulted in significant meniscal and regeneration and chondroprotection. In another study, subcutaneous implantation of hydroxyapatite scaffolds loaded with allogenic MSC allows cartilage obtention. The present clinical trials for cartilage repair are mainly focused on osteoarthritis 29 trials with auto- or allo-SC from bone marrow, umbilical cord, or adipose tissues [158160].

2.2.6. Dermatology

In mammals, cell renewal on the external surface of the skin is ensured by the keratinocytes of the basement layer which divide actively and are differentiated into cells of the stratum corneum. That activity implies the existence of SC. Unlike the SC of hair follicles confined in a niche, the SC of the epidermidis are spread along the basement membrane. The main clinical trials [10] are mainly on limb ischemia in diabetic patients [161, 162].

2.2.7. Pancreas and Diabetes [163]

The cell graft appears to be an alternative to the medical treatments for pancreas diseases. The first attempt of cell therapy by grafting of islets of Langerhans was published more than ten years ago [164167]. Other cell sources have also been proposed for pancreas and diabetes cell therapy like adult [168, 169] or fetal [170172] MSC, embryonic stem cells [173175], or even IPS [176, 177] because of their differentiation potential into insulin-producing cells and their immunomodulatory properties. Two studies with different therapeutic approaches are currently investigating the influence of cord blood stem cells on improving the function of pancreatic beta cells. In the first approach, children with young-onset diabetes are infused with autologous cord blood without chemotherapy. Initial results have shown that such autologous cord blood transplantation without chemotherapy has not resulted in adverse effects but has not significantly improved the situation either. All children are still dependent on administration of insulin. In the second approach, adult patients with newly diagnosed diabetes mellitus underwent nonmyeloablative chemotherapy after receiving reinfused stem cells from autologous bone marrow. Different trials on diabetes [22] type 1 or 2 are mainly performed with autologous or allogenic bone marrow or Wharton’s jelly MSC [178181].

2.2.8. Liver Diseases

In response to a variety of chronic injuries such as hepatitis, alcohol or drug abuse, metabolic diseases, autoimmune attack of hepatocytes or the bile duct epithelium, and congenital abnormalities, liver fibrosis occurs and finally leads to hepatic cirrhosis and liver failure. Liver transplantation is the accepted treatment option for this end-stage liver diseases and acute liver failure resulting in irreversible liver dysfunction. However, it is limited by the shortage of donor organs. Moreover, it is difficult to accept such a heavy surgical treatment for some patients because of the shortage of donor organs. In fact, correction of hepatocyte functional deficiency is the prime goal of liver transplantation. There is growing evidence in support of cell therapy. As an alternative to liver transplantation, some authors tried to use hepatocytes to treat patients with liver diseases instead of liver transplantation. However, the obstacle against their clinical applications is the requirement of large number of hepatocytes that are not available from patients themselves and as well as from other donors either. Thus, it is necessary to search for a novel source of cells. SC therapy has been accepted as one of the new approaches to recolonize liver. Several studies reported the hepatocyte differentiation potential of embryonic, fetal, or adult MSC but also IPS [182187].

As the liver contains three different cell types, which are organized in three-dimensional structures, growth and regeneration processes are highly complex. Therefore the idea of using one-type of SC leading to these three types of cells to repair liver is acceptable. Various populations of SC are under investigation in terms of their regenerative capabilities. Recently, studies showed that extrahepatic adult MSC of different origins have demonstrated their ability to express a hepatocyte-like phenotype after being differentiated in vitro. These cells which include MSC derived from bone marrow, umbilical cord, adipose tissue, and placenta are used in 32 trials mainly for cirrhosis (after hepatitis, alcohol abuse, and liver transplantation) [188191].

2.2.9. Urology and Erectile Dysfunction

The group of Atala in USA performed urethra transplant in young patients, prepared in vitro from bladder cells cultivated on a collagen and polyglycol acid matrix [192].

Recently, the SC therapy for erectile dysfunction has been investigated. Transplantation of SC (adipose-derived stem cells or bone marrow stem cells…) was performed by intracavernous injection [193, 194]. More recent studies used combinatory therapy by supplementing stem cells with angiogenic proteins. The different studies reported better erectile function after SC mainly by intracavernous injection [195].

The main potential applications are postprostatectomy and postradiotherapy, diabetes associated erectile dysfunction, and Peyronie’s disease [196]. Human clinical trial of erectile dysfunction with SC is not yet approved as treatment but one clinical trial in Korea was published in 2010 and two preclinical trials have been approved in USA and France.

2.2.10. Retina

The different ophthalmologic treatments with SC (mainly bone marrow) are related to retina diseases, macular degeneration, glaucoma, and hereditary dystrophy [197199].

2.2.11. Hematology: Preparation of Red Blood Cells

In vivo production of red blood cells (RBC) can be of a great practical interest. Recently, RBC preparation has been possible in vitro based on CD34+ stem cells [200, 201]. The protocol is in three steps: (1) proliferation and induction of the erythroid differentiation, (2) culture on a model reproducing the physiological microenvironment with mesenchymal cells, and (3) culture in the presence of stromal cells alone and without any growth factor. With this protocol, the cells undergo the various phases of differentiation to red cells. The industrial development would require developing suitable bioreactors. Another solution would be to have a permanent and unlimited supply of blood products. A first option is to use embryonic SC whose differentiation gives: first CD34+ stem cells, then erythrocytes [202]. Another approach consists in using induced pluripotent SC or IPS [203]. Different lineages of IPS and/or embryonic SC are currently used experimentally; beyond the difficulties in controlling complete differentiation, one major issue to be solved is that of insufficient yields [204].

2.3. Stem Cells and Whole Organ Engineering

The relevance of research into the creation of reconstructed organs is justified by the lack of organs available for transplantation and the growing needs for an ageing population. On a technical level, the development of these reconstructed organs involves two complementary stages: decellularization of the target organ with a need to maintain the structural integrity of the extracellular matrix and recellularization of the matrix with stem cells or resident cells [205, 206].

Whole organ engineering like liver, kidneys, heart, or lung is particularly difficult because of the structural complexity and heterogeneity of organ and cell types. But new ways of researches are currently focused on the matrix to support recellularization and a promising approach is the direct use of extracellular matrix of the whole organ. Thus rodent, porcine, and rhesus monkey organs have been decellularized to obtain a scaffold with preserved extracellular matrix and vascular network.

Decellularization can be achieved through an intra-arterial infusion of a solution containing the detergent Triton X-100 and ammonium hydroxide. This method causes all the cellular elements to disappear, leaving elements of the extracellular matrix and the vascular system. Other methods of decellularization have also been used, employing other chemicals, enzymes, or physical ways (ultrasounds) [207, 208].

Several types of cell can be considered for recellularization purposes: SC (embryonic, fetal, and adult SC) or the patient’s autologous cells. SC probably represent the ideal source of material due to their ability to proliferate. Their use appears to be limited, nevertheless, by their allogenic nature, which could possibly trigger an immune response and consequent rejection, in addition to the risk with ESC of the formation of teratomas in vivo. Fetal cells conserve their ability to proliferate and are easily differentiated without running the risk of induction of teratomas in vivo. These obstacles could be removed in future by using nuclear transfer techniques from the patient’s somatic cells (IPS). Finally, the stem or progenitor cells present in most organs are another source of cells that could be used for in vitro organogenesis. But, they often remain difficult to define, isolate, and grow in culture.

Furthermore, the type and number of cells to be used for recellularization vary depending on the organ to be reconstructed. Apparently, specific cells of the organ to be reconstructed are indispensable. Other types of cell, such as endothelial cells and fibroblasts, are also needed, since they promote the functional cell phenotype and contribute to the structural organization of tissue. The matrix of the vascular system of the organ to be reconstructed needs to be reendothelialized so as to orientate the blood flow and prevent thrombosis.

Currently, growing organs in vitro and ex vivo can take several weeks until they have completely developed in the matrix. For seeding the use of an extracorporeal pulsating or continuous infusion system (bioreactor) is indispensable for providing the cells with an oxygen supply and keeping the infusate at a constant temperature [209, 210]. The infusion liquids are derived from the culture media used for the cells in question. They need to contain growth factors or other molecules that are more specific to each organ. Finally, there is another hypothetical possibility for recellularization, the transplanting of a decellularized organ into the recipient, in the hope that recellularization will occur directly from the recipient’s own cells.

Encouraging work has recently shown the feasibility of creating bioorgans for the reconstruction of heart, lungs, liver, and kidneys. Clinical applications still remain a distant prospect, however.

2.3.1. Heart

Heart construction could be an alternate option for the treatment of cardiac insufficiency in the future. It is based on the use of an extra-cellular matrix coming from an animal’s heart and seeded with cells likely to reconstruct a normal cardiac function. Though the decellularization techniques now seem to be under control, the issues posed by the selection of the cells capable of generating the various components of cardiac tissue are not settled yet. In addition, the recolonization of the matrix does not only depend on the phenotype of cells that are used but also impacted by the nature of biochemical signals emitted. The complexity of those problems results in the full replacement of the heart with a biomaterial substitutes to standard transplanting is one prospect [211]. However, it is more realistic to hope, in the medium run, partial replacements of the heart with recellularized matrices reinforcing portions of the failing myocardium or with direct cellular therapy with SC.

The decellularization of animal hearts (rats and, more recently, hearts of large mammals) has been performed by D. Taylor through the infusion of chemical detergents. This study shows that the integrity of the matrix (collagen, fibronectin, laminin, fiber orientation, etc.) can be maintained as well as the permeability of the vascular tree and the competence of the heart valves [212].

Recellularization is more difficult due to the diversity of the cell populations that need to be reconstituted. Three ways to achieve this goal can be considered. (i) Use of a single population of pluripotent cells is capable of giving rise to all types of heart cells through the effect of environmental signals (an approach that appears currently to be rather unrealistic). (ii) Use of adult cells already differentiated for target lineages. The obtaining of fibroblasts and vascular cells can be achieved, especially as they can be taken from a future “recipient” of the reconstituted organ, as has been successfully demonstrated in the creation of implantable blood vessels. (iii) The third intermediate strategy consists of using a single population of progenitor cells at the mesodermic stage that would be liable, depending on the signals produced by the host tissue, to achieve differentiation in situ in the three main cell types (cardiomyocytes, endothelial cells, and smooth muscle cells). The problem of obtaining cardiogenic cells is also more complex since they not only need intrinsically contractile properties, but they must also be capable of coupling and modulating their frequency in response to neurohumoral or pharmacological stimuli. The plasticity of adult somatic cells is limited; however, it does not allow them to differentiate into cardiomyocytes. This property is only possessed by pluripotent cells, capable of acquiring a cardiac phenotype under the influence of the appropriate signal inducers. Such pluripotent cells could be human embryonic stem cells (hESC) whose allogenic character poses the problem of rejection (to say nothing of the ethics debate) or autologous, adult somatic SC rendered pluripotent through reprogramming (IPS). Regardless of the origin of such pluripotent cells, however, their clinical use implies an in vitro differentiation stage and then a selection process so that only the cardiogenic progenitors would be used. More recently, a direct conversion of the adult cells (fibroblasts) into cardiomyocytes has been proposed, again passing through the pluripotent cell stage. This approach still seems to be remote for clinical applications [213].

An important challenge is the transfer of cells into the matrix to recolonized [214]. While cell infusion destined for the vascular system appears to be logical for the endothelium, intramural injection of cells for cardiogenic purposes is less obvious.

In summary, by the complete replacement of a human heart by another heart constituted from a matrix of animal origin and seeded by cells capable of providing the organ with effective, mechanical activity remains a remote prospect and is unlikely to become a reality within the next 10 to 20 years.

Another strategy for cardiac repair is the preparation of cardiac patch [215, 216]. The construction of the high biocompatible biomaterials pretreated with SC will offer a promising method to improve the effects of SC therapy for myocardial infarction. Thus the development of this cardiac SC patch has high therapeutic perspectives for the treatment of the disease and prevention of the chronic heart failure. However the materials suitable for the treatment of MI need to have specific quality: biocompatibility, resistant to the mechanical force in situ, suitable for the cell amplification, and being with suitable size of pores for the cell communication which is necessary for the formation of the functional tissue. Under microscope, the pore size needs to be at least 50 μm which is necessary for the vascularization of the patch and assure the MSC metabolism. The biological materials have more advantages than artificial materials because the integration of the cells is optimal for the construction of the cardiac SC patch. As the MSC derived from Wharton’s jelly are easy to collect, the umbilical artery can be collected at the same time. The natural matrix of the umbilical artery possesses the essential property for the construction of a biocompatible cardiac patch.

2.3.2. Lungs

About fifty million people throughout the world are living with chronic respiratory failure at a terminal stage. The only treatment for this disease that seriously reduces life expectancy is, in selected cases, lung transplantation, but the results still are poor.

A tracheobronchial graft remains a challenge [217221]. Research has not yet found an ideal cell substitute for the airways of the lung. Failures have been observed with synthetic prostheses, bioprostheses, tracheal allografts, and autografts. In fact, not only epithelial tissue regeneration but also even cartilaginous regeneration has been observed. Research seems to indicate that this regeneration of tracheal tissue might be possible from an aortic matrix and SC taken from bone marrow [217]. Studies have been performed in humans in the context of extended cancer of the trachea and conservation surgery in cases of lung cancer. The research has also contributed to better understand tissue regeneration mechanisms [222].

Pulmonary regeneration using SC is more complex [223]. In fact, several types of local progenitor cells that contribute to cell repair have been described at different levels of the respiratory tract. Moving towards the alveolus, one finds bronchioloalveolar SC as well as epithelial cells and pneumocytes. In the category of “local SC,” cells of the subpopulation have been identified that are differentiation markers which in vitro mimic stromal mesenchymal cells. The role of these cells in tissue repair has been demonstrated in animal models. Recently it was described that resident, multipotent pulmonary SC are capable of self-renewal as well as clonogenicity. The phenotype and functional characteristics of these new cells have been specified in vitro and in vivo.

The lung also contains resident specific MSC that have been described and characterised [224226]. These cells do not play a direct part in epithelial renewal but establish communication with the epithelium, thus ensuring their role as a local cytoprotector [227].

Finally, numerous studies performed on animals have shown a beneficial role played by exogenous MSC produced by bone marrow. The effects observed in lesional pulmonary edema, sepsis, pulmonary hypertension, and even idiopathic pulmonary fibrosis have resulted in clinical applications that are currently being assessed [228231]. The immunomodulatory, anti-inflammatory, antiapoptotic, and angiogenic properties of MSC today place these cells at the heart of tissue repair. Contrary to past hypotheses, these cells do not seem to differentiate themselves into alveolar epithelial cells and their method of action would involve paracrine mechanisms, not all of which have as yet been explained.

With respect to the creation of a bioartificial lung,recent works on the subject have been realized with decellularized rat lung in order to obtain a supporting matrix [232]. Epithelial and endothelial cells were then injected into a pulmonary matrix followed by a five-day incubation period in a bioreactor. Morphological studies found an aspect closely resembling the animal’s own lung with respect to the alveolar cells (volume, number, and size) and in vitro physiological studies also showed that the ventilatory capacities and gas exchanges had also been maintained. An in vivo implantation of the bioartificial lung produced spontaneous ventilation for six hours. After this, pulmonary edema occurred. Several research routes, such as improvement in differentiation and maturation of the injected cells, a longer incubation period in the bioreactor and optimization of postoperative ventilation have been proposed.

Recently, others authors also decellularized a rat lung using chemical treatment, retaining only the framework matrix of the lung. This decellularized lung was then placed in a bioreactor that was used to mime the physiological conditions (negative pressure and pulsatile vascular perfusion). Epithelial cells from new-born rats were injected through the trachea and endothelial cells were injected into the vascular system. After four to eight days of incubation, this biolung was grafted on to a rat [221]. The compliance measurements were substantially different between the native lung, the decellularized lung, and the lung produced by bioengineering, with greater opening pressures reflecting a less functional surfactant in the bioengineered lung. Yet there was nothing to indicate rigidity of the matrix, thus ruling out the development of fibrosis, and gaseous exchanges were covered, attesting to the functional nature of this lung.

The decellularization of lungs was then reproduced on the lungs of pigs, nonhuman primates, and even humans [233235]. Embryonic SC or MSC were used to cellularize decellularized lungs [235237].

This initial research opens up a promising route for developing a functional bioartificial lung, with the prospect of application to humans within 15 to 20 years [238]. However many questions remain to be answered: is the use of a decellularized pulmonary matrix the only possible solution? Which cells should be chosen for recellularization, MSC or resident pulmonary cells? What is the optimal incubation time in a bioreactor? Would the technique be applicable to the human lung with its very extensive alveolar surface?

2.3.3. Liver

Recent researches have shown that it was possible to use decellularized liver treated by detergents as scaffold, which keeps the entire network of blood vessels and the ECM [239]. The intact blood vessel network will mimic the circulation in organ and provide appropriate oxygen and nutrient supply for bioartificial liver [240]. The ECM is composed of a complex mixture of molecules and arranged in three-dimensional spatial organization that support the cell seeding, growth, and differentiation. Decellularized liver keeps the texture of the original organ. This natural structure can provide a three-dimensional matrix in favor of cell proliferation, differentiation, and function, which promotes the emergence of the idea to use decellularized organ in bioengineering liver. The liver decellularization is carried out by perfusing detergents like Triton X-100 or sodium dodecyl sulfate, via the portal vein [241]. This method can destroy cell membrane and take off debris of cells and at the same time keeps the extracellular matric complete with blood and biliary vessels. This matrix maintains the liver-specific proteins proportions for collagens I and IV, fibronectin, and laminin. The intact vascular system is useful for recellularization.

Besides decellularized whole organ scaffold, the choice of cells selected to repopulate a decellularized liver scaffold is critical to the function of bioengineered liver. At present, potential cell sources are hepatocyte and MSC. SC, such as liver stem cells, ESC, IPSCs, and MSC, are a promising alternative for primary hepatocytes. Recent studies have shown that MSC originated from extrahepatic tissues can differentiate into endoderm cell-lines as hepatocytes. Several methods have successfully differentiated MSC into hepatocytes, such as stimulation MSC by cytokines as growth factors direct and indirect coculture of MSC with hepatocytes, or promotion of MSC differentiation in a three-dimensional matrix. In some cases, differentiation of MSC into hepatocytes can also be an alternative approach for whole organ transplantation in treatment of acute and chronic liver diseases [183]. Moreover, it has been shown that decellularized liver scaffold supports hepatic differentiation of MSC, leading to cells with morphological and functional characteristics of mature hepatocytes [242, 243].

2.3.4. Kidney [244246]

The kidney is certainly one of the most difficult organs to reconstruct due to its tissue complexity and the heterogeneous nature of the cells from which it is constituted. There is relatively few researches on kidney autoconstruction, though experiments performed on rats, pigs, and monkeys [247]. The first demonstration of the feasibility of the technique was provided by Ross in the rat [248]. They seeded the decellularized organ with pluripotent murine embryonic stem cells antegrade through the artery or retrograde through the ureter. The cells introduced were differentiated into glomerular, tubular, and vascular structures. They nevertheless lost their embryonic phenotype as it could be seen from the appearance of immunohistochemical markers. Nakayama et al. [249] decellularized sections of the kidneys taken from macaques at various growth stages from fetus to adult, via intermediate ages, with the aim of optimizing decellularization techniques and recellularization in vitro [249, 250]. They demonstrated that the appearance of Pax-2 and vimentin markers after the cells had been implanted originated from the kidneys of the fetus.

As with other organs, the research into the construction of a kidney raises numerous questions about the preparation of a matrix and the sources of the cells used for recellularization. Biological matrices have proved their superiority over the synthetic matrices sometimes used in tissue engineering. In the case of the kidney, the most frequently employed matrices are allogenic, even though xenogeneic matrices can be considered, although they might be subject to specific immunological and regulatory issues.

In summary, a large number of questions and problems remain to be solved before a kidney can be prepared or constructed from ECM. Furthermore, none of the “self-constructed” organs in animals has proved to be capable of performing the vital function in the recipient for longer than a few hours. In the case of the kidney, no transplant has yet been reported even though it is the main challenge for research. The objective remains plausible, however, even if clinical applications appear to be very remote, certainly not before 15 to 20 years.

3. MSC Secretome for Tissue Repair: Towards a Cell-Free Therapy

Even if initially MSC were proposed for cell therapy based on their differentiation potential, the lack of correlation between functional improvement and cell engraftment or differentiation at the site of injury has led to the proposal that MSC exert their effects not through their differentiation potential but through their secreted product [251, 252]. The secretion of bioactive factors is then thought to play a predominant role in the mechanisms of action of MSC. Haynesworth et al. [253] were the first to report that MSC synthesize and secrete a broad spectrum of growth factors, chemokines, and cytokines that could exert significant effects on cells in their vicinity. Since that, many researches have been focused on the characterization of the MSC secretome, including both soluble factors and factors released in extracellular vesicles (e.g., exosomes and microvesicles) and their therapeutic potential [254256].

The results from most investigations show that MSC-conditioned medium or its components mediate some biological functions of MSC. Several studies have reported that MSC-derived exosomes have functions similar to those of MSC, such as repairing tissue damage, suppressing inflammatory responses, modulating the immune system, or even decreasing cancer cells proliferation [257264].

Together these studies provided pivotal support for the paracrine hypothesis such that MSC therapy is increasingly rationalized on MSC secretion rather than its differentiation potential. However, the mechanisms are still not fully understood and the results remain controversial. Compared with cells, exosomes are more stable and reservable, have no risk of aneuploidy, a lower possibility of immune rejection following in vivo allogeneic administration, and may provide an alternative therapy for various diseases.

4. Conclusions

The regeneration of tissues and organs and the use of SC for clinical uses are and will remain a challenge for the development of cell therapy and tissue engineering. Fetal and adult SC and in particular MSC provide exciting therapeutic tools of regenerative medicine. However basic research should be developed to better understand the biological process and molecular mechanism of SC differentiation, as well as the role of the mechanical signals.

Several challenges should be overcome:(i)increase of the yield of preparation of the differentiated stem cells and study of the heterogeneous character of the preparations;(ii)possibility to have a standardized and reproducible product (preparation of controlled batches);(iii)technical problems regarding the definition of scaffolds, cells used, long-term stability, and culture medium. In particular, the impact of the biomaterial used remains to be defined;(iv)grafting (biotissue can be introduced via direct cell implantation (cell therapy), biotissue transplantation, or gene therapy);(v)risk of teratogenic effect and of immune reaction (i.e., in the umbilical cord cells the immune risk being weaker);(vi)religious and legal issues with respect to the different country regulations.

Current knowledge allows optimism for the future but definitive answers can only be given after long-term randomized and controlled clinical trials.

Conflict of Interests

The authors declare that there is no conflict of interests regarding the publication of this review.

Authors’ Contribution

J.-F. Stoltz and N. de Isla contributed equally.


The Région Lorraine, French embassy in Beijing and Wuhan French Consulate are acknowledged for their financial support of this paper.


  1. A. Islam, “Haemopoietic stem cell: a new concept,” Leukemia Research, vol. 9, no. 11, pp. 1415–1432, 1985. View at: Google Scholar
  2. M. Tavassoli and A. Friedenstein, “Hemopoietic stromal microenvironment,” The American Journal of Hematology, vol. 15, no. 2, pp. 195–203, 1983. View at: Publisher Site | Google Scholar
  3. E. D. Thomas, H. L. Lochte Jr., J. H. Cannon, O. D. Sahler, and J. W. Ferrebee, “Supralethal whole body irradiation and isologous marrow transplantation in man,” The Journal of Clinical Investigation, vol. 38, pp. 1709–1716, 1959. View at: Publisher Site | Google Scholar
  4. R. A. Gatti, H. J. Meuwissen, H. D. Allen, R. Hong, and R. A. Good, “Immunological reconstitution of sex-linked lymphopenic immunological deficiency,” The Lancet, vol. 2, no. 7583, pp. 1366–1369, 1968. View at: Google Scholar
  5. E. D. Thomas, “A history of haemopoietic cell transplantation,” British Journal of Haematology, vol. 105, no. 2, pp. 330–339, 1999. View at: Publisher Site | Google Scholar
  6. M. J. Evans and M. H. Kaufman, “Establishment in culture of pluripotential cells from mouse embryos,” Nature, vol. 292, no. 5819, pp. 154–156, 1981. View at: Publisher Site | Google Scholar
  7. G. R. Martin, “Isolation of a pluripotent cell line from early mouse embryos cultured in medium conditioned by teratocarcinoma stem cells,” Proceedings of the National Academy of Sciences of the United States of America, vol. 78, no. 12, pp. 7634–7638, 1981. View at: Publisher Site | Google Scholar
  8. K. Takahashi and S. Yamanaka, “Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors,” Cell, vol. 126, no. 4, pp. 663–676, 2006. View at: Publisher Site | Google Scholar
  9. K. Takahashi, K. Tanabe, M. Ohnuki et al., “Induction of pluripotent stem cells from adult human fibroblasts by defined factors,” Cell, vol. 131, no. 5, pp. 861–872, 2007. View at: Publisher Site | Google Scholar
  10. E. Galende, I. Karakikes, L. Edelmann et al., “Amniotic fluid cells are more efficiently reprogrammed to pluripotency than adult cells,” Cellular Reprogramming, vol. 12, no. 2, pp. 117–125, 2010. View at: Publisher Site | Google Scholar
  11. C. Magnon, D. Lucas, and P. Frenette, “Trafficking of stem cells,” in Stem Cell Migration: Methods and Protocols, vol. 750 of Methods in Molecular Biology, pp. 3–24, Humana Press, New York, NY, USA, 2011. View at: Publisher Site | Google Scholar
  12. T. Zhao, Z.-N. Zhang, Z. Rong, and Y. Xu, “Immunogenicity of induced pluripotent stem cells,” Nature, vol. 474, no. 7350, pp. 212–215, 2011. View at: Publisher Site | Google Scholar
  13. C. Campagnoli, I. A. G. Roberts, S. Kumar, P. R. Bennett, I. Bellantuono, and N. M. Fisk, “Identification of mesenchymal stem/progenitor cells in human first-trimester fetal blood, liver, and bone marrow,” Blood, vol. 98, no. 8, pp. 2396–2402, 2001. View at: Publisher Site | Google Scholar
  14. V. Dexheimer, S. Mueller, F. Braatz, and W. Richter, “Reduced reactivation from dormancy but maintained lineage choice of human mesenchymal stem cells with donor age,” PLoS ONE, vol. 6, no. 8, Article ID e22980, 2011. View at: Publisher Site | Google Scholar
  15. Y. Fukuchi, H. Nakajima, D. Sugiyama, I. Hirose, T. Kitamura, and K. Tsuji, “Human placenta-derived cells have mesenchymal stem/progenitor cell potential,” Stem Cells, vol. 22, no. 5, pp. 649–658, 2004. View at: Google Scholar
  16. C. A. Roufosse, N. C. Direkze, W. R. Otto, and N. A. Wright, “Circulating mesenchymal stem cells,” International Journal of Biochemistry and Cell Biology, vol. 36, no. 4, pp. 585–597, 2004. View at: Publisher Site | Google Scholar
  17. D. Suva, G. Garavaglia, J. Menetrey et al., “Non-hematopoietic human bone marrow contains long-lasting, pluripotential mesenchymal stem cells,” Journal of Cellular Physiology, vol. 198, no. 1, pp. 110–118, 2004. View at: Publisher Site | Google Scholar
  18. W. Wagner, F. Wein, A. Seckinger et al., “Comparative characteristics of mesenchymal stem cells from human bone marrow, adipose tissue, and umbilical cord blood,” Experimental Hematology, vol. 33, no. 11, pp. 1402–1416, 2005. View at: Publisher Site | Google Scholar
  19. H.-S. Wang, S.-C. Hung, S.-T. Peng et al., “Mesenchymal stem cells in the Wharton's jelly of the human umbilical cord,” Stem Cells, vol. 22, no. 7, pp. 1330–1337, 2004. View at: Publisher Site | Google Scholar
  20. B. L. Yen, H.-I. Huang, C.-C. Chien et al., “Isolation of multipotent cells from human term placenta,” Stem Cells, vol. 23, no. 1, pp. 3–9, 2005. View at: Publisher Site | Google Scholar
  21. G. Yu, X. Wu, M. A. Dietrich et al., “Yield and characterization of subcutaneous human adipose-derived stem cells by flow cytometric and adipogenic mRNA analyzes,” Cytotherapy, vol. 12, no. 4, pp. 538–546, 2010. View at: Publisher Site | Google Scholar
  22. B. M. Abdallah and M. Kassem, “Human mesenchymal stem cells: from basic biology to clinical applications,” Gene Therapy, vol. 15, no. 2, pp. 109–116, 2008. View at: Publisher Site | Google Scholar
  23. S. Aggarwal and M. F. Pittenger, “Human mesenchymal stem cells modulate allogeneic immune cell responses,” Blood, vol. 105, no. 4, pp. 1815–1822, 2005. View at: Publisher Site | Google Scholar
  24. N. A. Kia, A. R. Bahrami, M. Ebrahimi et al., “Comparative analysis of chemokine receptor's expression in mesenchymal stem cells derived from human bone marrow and adipose tissue,” Journal of Molecular Neuroscience, vol. 44, no. 3, pp. 178–185, 2011. View at: Publisher Site | Google Scholar
  25. A. Can and S. Karahuseyinoglu, “Concise review: human umbilical cord stroma with regard to the source of fetus-derived stem cells,” Stem Cells, vol. 25, no. 11, pp. 2886–2895, 2007. View at: Publisher Site | Google Scholar
  26. M. Dominici, K. Le Blanc, I. Mueller et al., “Minimal criteria for defining multipotent mesenchymal stromal cells: the international society for cellular therapy position statement,” Cytotherapy, vol. 8, no. 4, pp. 315–317, 2006. View at: Publisher Site | Google Scholar
  27. J. A. Efe, S. Hilcove, J. Kim et al., “Conversion of mouse fibroblasts into cardiomyocytes using a direct reprogramming strategy,” Nature Cell Biology, vol. 13, no. 3, pp. 215–222, 2011. View at: Publisher Site | Google Scholar
  28. A. Mojallal, C. Lequeux, C. Shipkov et al., “Influence of age and body mass index on the yield and proliferation capacity of Adipose-derived stem cells,” Aesthetic Plastic Surgery, vol. 35, no. 6, pp. 1097–1105, 2011. View at: Publisher Site | Google Scholar
  29. L. V. Rodríguez, Z. Alfonso, R. Zhang, J. Leung, B. Wu, and L. J. Ignarro, “Clonogenic multipotent stem cells in human adipose tissue differentiate into functional smooth muscle cells,” Proceedings of the National Academy of Sciences of the United States of America, vol. 103, no. 32, pp. 12167–12172, 2006. View at: Publisher Site | Google Scholar
  30. R. Sarugaser, D. Lickorish, D. Baksh, M. M. Hosseini, and J. E. Davies, “Human umbilical cord perivascular (HUCPV) cells: a source of mesenchymal progenitors,” Stem Cells, vol. 23, no. 2, pp. 220–229, 2005. View at: Publisher Site | Google Scholar
  31. J.-W. Yang, N. de Isla, C. Huselstein et al., “Evaluation of human MSCs cell cycle, viability and differentiation in micromass culture,” Biorheology, vol. 43, no. 3-4, pp. 489–496, 2006. View at: Google Scholar
  32. M. Malinowski, K. Pietraszek, C. Perreau et al., “Effect of lumican on the migration of human mesenchymal stem cells and endothelial progenitor cells: involvement of matrix metalloproteinase,” PLoS ONE, vol. 7, no. 12, Article ID e50709, 2012. View at: Publisher Site | Google Scholar
  33. J. Oswald, S. Boxberger, B. Jørgensen et al., “Mesenchymal stem cells can be differentiated into endothelial cells in vitro,” Stem Cells, vol. 22, no. 3, pp. 377–384, 2004. View at: Google Scholar
  34. M. F. Pittenger, A. M. Mackay, S. C. Beck et al., “Multilineage potential of adult human mesenchymal stem cells,” Science, vol. 284, no. 5411, pp. 143–147, 1999. View at: Publisher Site | Google Scholar
  35. V. Planat-Benard, J.-S. Silvestre, B. Cousin et al., “Plasticity of human adipose lineage cells toward endothelial cells: physiological and therapeutic perspectives,” Circulation, vol. 109, no. 5, pp. 656–663, 2004. View at: Publisher Site | Google Scholar
  36. N. Salmon, E. Paternotte, V. Decot, J.-F. Stoltz, P. Menu, and P. Labrude, “Polyelectrolyte multilayer films promote human cord blood stem cells differentiation into mature endothelial cells exhibiting a stable phenotype,” Bio-Medical Materials and Engineering, vol. 19, no. 4-5, pp. 349–354, 2009. View at: Publisher Site | Google Scholar
  37. A. Allameh, H. Ahmadi-Ashtiani, M. S. Emami Aleagha, and H. Rastegar, “The metabolic function of hepatocytes differentiated from human mesenchymal stem cells is inversely related to cellular glutathione levels,” Cell Biochemistry and Function, vol. 32, no. 2, pp. 194–200, 2014. View at: Publisher Site | Google Scholar
  38. L. Zhang, Y.-H. Zhao, Z. Guan, J.-S. Ye, N. de Isla, and J.-F. Stoltz, “Application potential of mesenchymal stem cells derived from Wharton's jelly in liver tissue engineering,” Bio-Medical Materials and Engineering, vol. 25, no. 1, supplement, pp. 137–143, 2015. View at: Publisher Site | Google Scholar
  39. J.-S. Ye, X.-S. Su, J.-F. Stoltz, N. de Isla, and L. Zhang, “Signalling pathways involved in the process of mesenchymal stem cells differentiating into hepatocytes,” Cell Proliferation, vol. 48, no. 2, pp. 157–165, 2015. View at: Publisher Site | Google Scholar
  40. N. Feng, Q. Han, J. Li et al., “Generation of highly purified neural stem cells from human adipose-derived mesenchymal stem cells by Sox1 activation,” Stem Cells and Development, vol. 23, no. 5, pp. 515–529, 2014. View at: Publisher Site | Google Scholar
  41. M. M. Martini, T. D. S. Jeremias, M. C. Kohler, L. L. Marostica, A. G. Trentin, and M. Alvarez-Silva, “Human placenta-derived mesenchymal stem cells acquire neural phenotype under the appropriate niche conditions,” DNA and Cell Biology, vol. 32, no. 2, pp. 58–65, 2013. View at: Publisher Site | Google Scholar
  42. K. Ma, L. Fox, G. Shi et al., “Generation of neural stem cell-like cells from bone marrow-derived human mesenchymal stem cells,” Neurological Research, vol. 33, no. 10, pp. 1083–1093, 2011. View at: Publisher Site | Google Scholar
  43. G. Chamberlain, J. Fox, B. Ashton, and J. Middleton, “Concise review: Mesenchymal stem cells: their phenotype, differentiation capacity, immunological features, and potential for homing,” Stem Cells, vol. 25, no. 11, pp. 2739–2749, 2007. View at: Publisher Site | Google Scholar
  44. K. Chen, D. Wang, W. T. Du et al., “Human umbilical cord mesenchymal stem cells hUC-MSCs exert immunosuppressive activities through a PGE2-dependent mechanism,” Clinical Immunology, vol. 135, no. 3, pp. 448–458, 2010. View at: Publisher Site | Google Scholar
  45. A. Corcione, F. Benvenuto, E. Ferretti et al., “Human mesenchymal stem cells modulate B-cell functions,” Blood, vol. 107, no. 1, pp. 367–372, 2006. View at: Publisher Site | Google Scholar
  46. L. Reppel, T. Margossian, L. Yaghi et al., “Hypoxic culture conditions for Mesenchymal Stromal/Stem Cells from Wharton's jelly: a critical parameter to consider in a therapeutic context,” Current Stem Cell Research & Therapy, vol. 9, no. 4, pp. 306–318, 2014. View at: Publisher Site | Google Scholar
  47. D. E. Wright, A. J. Wagers, A. P. Gulati, F. L. Johnson, and I. L. Weissman, “Physiological migration of hematopoietic stem and progenitor cells,” Science, vol. 294, no. 5548, pp. 1933–1936, 2001. View at: Publisher Site | Google Scholar
  48. H. H. Chen, V. Decot, J. P. Ouyang, J. F. Stoltz, D. Bensoussan, and N. G. De Isla, “In vitro initial expansion of mesenchymal stem cells is influenced by the culture parameters used in the isolation process,” Bio-Medical Materials and Engineering, vol. 19, no. 4-5, pp. 301–309, 2009. View at: Publisher Site | Google Scholar
  49. E. U. Alt, C. Senst, S. N. Murthy et al., “Aging alters tissue resident mesenchymal stem cell properties,” Stem Cell Research, vol. 8, no. 2, pp. 215–225, 2012. View at: Publisher Site | Google Scholar
  50. M. S. Rao and M. P. Mattson, “Stem cells and aging: expanding the possibilities,” Mechanisms of Ageing and Development, vol. 122, no. 7, pp. 713–734, 2001. View at: Publisher Site | Google Scholar
  51. B. M. Schipper, K. G. Marra, W. Zhang, A. D. Donnenberg, and J. P. Rubin, “Regional anatomic and age effects on cell function of human adipose-derived stem cells,” Annals of Plastic Surgery, vol. 60, no. 5, pp. 538–544, 2008. View at: Publisher Site | Google Scholar
  52. S. Zhou, J. S. Greenberger, M. W. Epperly et al., “Age-related intrinsic changes in human bone-marrow-derived mesenchymal stem cells and their differentiation to osteoblasts,” Aging Cell, vol. 7, no. 3, pp. 335–343, 2008. View at: Publisher Site | Google Scholar
  53. M. Zhu, E. Kohan, J. Bradley, M. Hedrick, P. Benhaim, and P. Zuk, “The effect of age on osteogenic, adipogenic and proliferative potential of female adipose-derived stem cells,” Journal of Tissue Engineering and Regenerative Medicine, vol. 3, no. 4, pp. 290–301, 2009. View at: Publisher Site | Google Scholar
  54. Y. Li, N. Charif, D. Mainard, D. Bensoussan, J.-F. Stoltz, and N. de Isla, “Donor's age dependent proliferation decrease of human bone marrow mesenchymal stem cells is linked to diminished clonogenicity,” Bio-Medical Materials and Engineering, vol. 24, no. 1, supplement, pp. 47–52, 2014. View at: Publisher Site | Google Scholar
  55. G. Brooke, H. Tong, J.-P. Levesque, and K. Atkinson, “Molecular trafficking mechanisms of multipotent mesenchymal stem cells derived from human bone marrow and placenta,” Stem Cells and Development, vol. 17, no. 5, pp. 929–940, 2008. View at: Publisher Site | Google Scholar
  56. J. W. Goodman and G. S. Hodgson, “Evidence for stem cells in the peripheral blood of mice,” Blood, vol. 19, pp. 702–714, 1962. View at: Google Scholar
  57. Y. Jiang, B. Vaessen, T. Lenvik, M. Blackstad, M. Reyes, and C. M. Verfaillie, “Multipotent progenitor cells can be isolated from postnatal murine bone marrow, muscle, and brain,” Experimental Hematology, vol. 30, no. 8, pp. 896–904, 2002. View at: Publisher Site | Google Scholar
  58. J. Tolar, M. J. O'Shaughnessy, A. Panoskaltsis-Mortari et al., “Host factors that impact the biodistribution and persistence of multipotent adult progenitor cells,” Blood, vol. 107, no. 10, pp. 4182–4188, 2006. View at: Publisher Site | Google Scholar
  59. M.-C. Kastrinaki, I. Andreakou, P. Charbord, and H. A. Papadaki, “Isolation of human bone marrow mesenchymal stem cells using different membrane markers: comparison of colony/cloning efficiency, differentiation potential, and molecular profile,” Tissue Engineering Part C: Methods, vol. 14, no. 4, pp. 333–339, 2008. View at: Publisher Site | Google Scholar
  60. M. F. Pera, “Stem cells: the dark side of induced pluripotency,” Nature, vol. 471, no. 7336, pp. 46–47, 2011. View at: Publisher Site | Google Scholar
  61. G. Brooke, M. Cook, C. Blair et al., “Therapeutic applications of mesenchymal stromal cells,” Seminars in Cell & Developmental Biology, vol. 18, no. 6, pp. 846–858, 2007. View at: Google Scholar
  62. A. Giordano, U. Galderisi, and I. R. Marino, “From the laboratory bench to the patient's bedside: an update on clinical trials with Mesenchymal Stem Cells,” Journal of Cellular Physiology, vol. 211, no. 1, pp. 27–35, 2007. View at: Publisher Site | Google Scholar
  63. K. Tarte, J. Gaillard, J.-J. Lataillade et al., “Clinical-grade production of human mesenchymal stromal cells: occurrence of aneuploidy without transformation,” Blood, vol. 115, no. 8, pp. 1549–1553, 2010. View at: Publisher Site | Google Scholar
  64. G. Brooke, T. Rossetti, R. Pelekanos et al., “Manufacturing of human placenta-derived mesenchymal stem cells for clinical trials,” British Journal of Haematology, vol. 144, no. 4, pp. 571–579, 2009. View at: Publisher Site | Google Scholar
  65. J. F. Stoltz, D. Dumas, X. Wang et al., “Influence of mechanical forces on cells and tissues,” Biorheology, vol. 37, no. 1-2, pp. 3–14, 2000. View at: Google Scholar
  66. T. Lapidot, C. Sirard, J. Vormoor et al., “A cell initiating human acute myeloid leukaemia after transplantation into SCID mice,” Nature, vol. 367, no. 6464, pp. 645–648, 1994. View at: Publisher Site | Google Scholar
  67. M. Al-Hajj, M. S. Wicha, A. Benito-Hernandez, S. J. Morrison, and M. F. Clarke, “Prospective identification of tumorigenic breast cancer cells,” Proceedings of the National Academy of Sciences of the United States of America, vol. 100, no. 7, pp. 3983–3988, 2003. View at: Publisher Site | Google Scholar
  68. S. K. Singh, C. Hawkins, I. D. Clarke et al., “Identification of human brain tumour initiating cells,” Nature, vol. 432, no. 7015, pp. 396–401, 2004. View at: Publisher Site | Google Scholar
  69. A. T. Collins, P. A. Berry, C. Hyde, M. J. Stower, and N. J. Maitland, “Prospective identification of tumorigenic prostate cancer stem cells,” Cancer Research, vol. 65, no. 23, pp. 10946–10951, 2005. View at: Publisher Site | Google Scholar
  70. C. Li, D. G. Heidt, P. Dalerba et al., “Identification of pancreatic cancer stem cells,” Cancer Research, vol. 67, no. 3, pp. 1030–1037, 2007. View at: Publisher Site | Google Scholar
  71. P. Dalerba, R. W. Cho, and M. F. Clarke, “Cancer stem cells: models and concepts,” Annual Review of Medicine, vol. 58, pp. 267–284, 2007. View at: Publisher Site | Google Scholar
  72. W.-T. Liao, Y.-P. Ye, Y.-J. Deng, X.-W. Bian, and Y.-Q. Ding, “Metastatic cancer stem cells: from the concept to therapeutics,” American Journal of Stem Cells, vol. 3, no. 2, pp. 46–62, 2014. View at: Google Scholar
  73. A. D. Kim, D. L. Stachura, and D. Traver, “Cell signaling pathways involved in hematopoietic stem cell specification,” Experimental Cell Research, vol. 329, no. 2, pp. 227–233, 2014. View at: Publisher Site | Google Scholar
  74. Y. Wu, Z. Wang, Y. Cao et al., “Cotransplantation of haploidentical hematopoietic and umbilical cord mesenchymal stem cells with a myeloablative regimen for refractory/relapsed hematologic malignancy,” Annals of Hematology, vol. 92, no. 12, pp. 1675–1684, 2013. View at: Publisher Site | Google Scholar
  75. Y. Wu, Y. Cao, X. Li et al., “Cotransplantation of haploidentical hematopoietic and umbilical cord mesenchymal stem cells for severe aplastic anemia: successful engraftment and mild GVHD,” Stem Cell Research, vol. 12, no. 1, pp. 132–138, 2014. View at: Publisher Site | Google Scholar
  76. J. J. Auletta, S. K. Eid, P. Wuttisarnwattana et al., “Human mesenchymal stromal cells attenuate graft-versus-host disease and maintain graft-versus-leukemia activity following experimental allogeneic bone marrow transplantation,” Stem Cells, vol. 33, no. 2, pp. 601–614, 2015. View at: Publisher Site | Google Scholar
  77. M. S. Cairo and J. E. Wagner, “Placental and/or umbilical cord blood: an alternative source of hematopoietic stem cells for transplantation,” Blood, vol. 90, no. 12, pp. 4665–4678, 1997. View at: Google Scholar
  78. J. Cany, H. Dolstra, and N. Shah, “Umbilical cord blood–derived cellular products for cancer immunotherapy,” Cytotherapy, vol. 17, no. 6, pp. 739–748, 2015. View at: Publisher Site | Google Scholar
  79. V. Rocha, C. Chastang, G. Souillet et al., “Related cord blood transplants: the Eurocord experience from 78 transplants,” Bone Marrow Transplantation, vol. 21, supplement 3, pp. S59–S62, 1998. View at: Publisher Site | Google Scholar
  80. E. Gluckman, “Ten years of cord blood transplantation: from bench to bedside,” British Journal of Haematology, vol. 147, no. 2, pp. 192–199, 2009. View at: Publisher Site | Google Scholar
  81. M. E. Horwitz and F. Frassoni, “Improving the outcome of umbilical cord blood transplantation through ex vivo expansion or graft manipulation,” Cytotherapy, vol. 17, no. 6, pp. 730–738, 2015. View at: Publisher Site | Google Scholar
  82. K. K. Ballen, E. Gluckman, and H. E. Broxmeyer, “Umbilical cord blood transplantation: the first 25 years and beyond,” Blood, vol. 122, no. 4, pp. 491–498, 2013. View at: Publisher Site | Google Scholar
  83. M. Gigante and E. Ranieri, “Role of cytotoxic CD4+ T cells in cancer immunotherapy,” Immunotherapy, vol. 2, no. 5, pp. 607–608, 2010. View at: Publisher Site | Google Scholar
  84. G. Zhang, H. Zhao, J. Wu et al., “Adoptive immunotherapy for non-small cell lung cancer by NK and cytotoxic T lymphocytes mixed effector cells: retrospective clinical observation,” International Immunopharmacology, vol. 21, no. 2, pp. 396–405, 2014. View at: Publisher Site | Google Scholar
  85. V. Decot, L. Voillard, V. Latger-Cannard et al., “Natural-killer cell amplification for adoptive leukemia relapse immunotherapy: comparison of three cytokines, IL-2, IL-15, or IL-7 and impact on NKG2D, KIR2DL1, and KIR2DL2 expression,” Experimental Hematology, vol. 38, no. 5, pp. 351–362, 2010. View at: Publisher Site | Google Scholar
  86. M. Cheng, Y. Chen, W. Xiao, R. Sun, and Z. Tian, “NK cell-based immunotherapy for malignant diseases,” Cellular & Molecular Immunology, vol. 10, no. 3, pp. 230–252, 2013. View at: Publisher Site | Google Scholar
  87. C. Eguizabal, O. Zenarruzabeitia, J. Monge et al., “Natural killer cells for cancer immunotherapy: pluripotent stem cells-derived NK cells as an immunotherapeutic perspective,” Frontiers in Immunology, vol. 5, article 439, 2014. View at: Publisher Site | Google Scholar
  88. Y. Zhang, L. Wang, D. Li, and N. Li, “Taming regulatory T cells by autologous T cell immunization: a potential new strategy for cancer immune therapy,” International Immunopharmacology, vol. 9, no. 5, pp. 593–595, 2009. View at: Publisher Site | Google Scholar
  89. L. Xu, W. Xu, Z. Jiang, F. Zhang, Y. Chu, and S. Xiong, “Depletion of CD4+ CD25high regulatory T cells from tumor infiltrating lymphocytes predominantly induces Th1 type immune response in vivo which inhibits tumor growth in adoptive immunotherapy,” Cancer Biology and Therapy, vol. 8, no. 1, pp. 66–72, 2009. View at: Google Scholar
  90. F. Dazzi and F. M. Marelli-Berg, “Mesenchymal stem cells for graft-versus-host disease: close encounters with T cells,” European Journal of Immunology, vol. 38, no. 6, pp. 1479–1482, 2008. View at: Publisher Site | Google Scholar
  91. K. Le Blanc, I. Rasmusson, B. Sundberg et al., “Treatment of severe acute graft-versus-host disease with third party haploidentical mesenchymal stem cells,” The Lancet, vol. 363, no. 9419, pp. 1439–1441, 2004. View at: Publisher Site | Google Scholar
  92. N. Kim, K.-I. Im, J.-Y. Lim et al., “Mesenchymal stem cells for the treatment and prevention of graft-versus-host disease: experiments and practice,” Annals of Hematology, vol. 92, no. 10, pp. 1295–1308, 2013. View at: Publisher Site | Google Scholar
  93. J. D. Glenn and K. A. Whartenby, “Mesenchymal stem cells: emerging mechanisms of immunomodulation and therapy,” World Journal of Stem Cells, vol. 6, no. 5, pp. 526–539, 2014. View at: Publisher Site | Google Scholar
  94. M. Introna and A. Rambaldi, “Mesenchymal stromal cells for prevention and treatment of graft-versus-host disease,” Current Opinion in Organ Transplantation, vol. 20, no. 1, pp. 72–78, 2015. View at: Publisher Site | Google Scholar
  95. N. Amariglio, A. Hirshberg, B. W. Scheithauer et al., “Donor-derived brain tumor following neural stem cell transplantation in an ataxia telangiectasia patient,” PLoS Medicine, vol. 6, no. 2, Article ID e1000029, 2009. View at: Publisher Site | Google Scholar
  96. J. Tritz-Schiavi, N. Charif, C. Henrionnet et al., “Original approach for cartilage tissue engineering with mesenchymal stem cells,” Bio-Medical Materials and Engineering, vol. 20, no. 3, pp. 167–174, 2010. View at: Publisher Site | Google Scholar
  97. A. I. Caplan and S. P. Bruder, “Mesenchymal stem cells: building blocks for molecular medicine in the 21st century,” Trends in Molecular Medicine, vol. 7, no. 6, pp. 259–264, 2001. View at: Google Scholar
  98. A. Schäffler and C. Büchler, “Concise review: adipose tissue-derived stromal cells—basic and clinical implications for novel cell-based therapies,” Stem Cells, vol. 25, no. 4, pp. 818–827, 2007. View at: Publisher Site | Google Scholar
  99. J. F. Stoltz, Ed., Regenerative Medicine and Cell Therapy, IOS Press, Amsterdam, The Netherlands, 2012.
  100. A. I. Caplan, “Adult mesenchymal stem cells for tissue engineering versus regenerative medicine,” Journal of Cellular Physiology, vol. 213, no. 2, pp. 341–347, 2007. View at: Publisher Site | Google Scholar
  101. H. Gai, E. L.-H. Leung, P. D. Costantino et al., “Generation and characterization of functional cardiomyocytes using induced pluripotent stem cells derived from human fibroblasts,” Cell Biology International, vol. 33, no. 11, pp. 1184–1193, 2009. View at: Publisher Site | Google Scholar
  102. R. E. Bittner, C. Schöfer, K. Weipoltshammer et al., “Recruitment of bone-marrow-derived cells by skeletal and cardiac muscle in adult dystrophic mdx mice,” Anatomy and Embryology, vol. 199, no. 5, pp. 391–396, 1999. View at: Publisher Site | Google Scholar
  103. A. Deb, S. Wang, K. A. Skelding, D. Miller, D. Simper, and N. M. Caplice, “Bone marrow-derived cardiomyocytes are present in adult human heart: a study of gender-mismatched bone marrow transplantation patients,” Circulation, vol. 107, no. 9, pp. 1247–1249, 2003. View at: Publisher Site | Google Scholar
  104. S. Itescu, A. A. Kocher, and M. D. Schuster, “Myocardial neovascularization by adult bone marrow-derived angioblasts: strategies for improvement of cardiomyocyte function,” Heart Failure Reviews, vol. 8, no. 3, pp. 253–258, 2003. View at: Publisher Site | Google Scholar
  105. S. Kang, Y. J. Yang, C. J. Li, and R. L. Gao, “Effects of intracoronary autologous bone marrow cells on left ventricular function in acute myocardial infarction: a systematic review and meta-analysis for randomized controlled trials,” Coronary Artery Disease, vol. 19, no. 5, pp. 327–335, 2008. View at: Publisher Site | Google Scholar
  106. M. A. Laflamme, D. Myerson, J. E. Saffitz, and C. E. Murry, “Evidence for cardiomyocyte repopulation by extracardiac progenitors in transplanted human hearts,” Circulation Research, vol. 90, no. 6, pp. 634–640, 2002. View at: Publisher Site | Google Scholar
  107. R.-J. Swijnenburg, M. Tanaka, H. Vogel et al., “Embryonic stem cell immunogenicity increases upon differentiation after transplantation into ischemic myocardium,” Circulation, vol. 112, no. 9, supplement, pp. I166–I172, 2005. View at: Publisher Site | Google Scholar
  108. J. Tang, Q. Xie, G. Pan, J. Wang, and M. Wang, “Mesenchymal stem cells participate in angiogenesis and improve heart function in rat model of myocardial ischemia with reperfusion,” European Journal of Cardio-Thoracic Surgery, vol. 30, no. 2, pp. 353–361, 2006. View at: Publisher Site | Google Scholar
  109. C. Toma, M. F. Pittenger, K. S. Cahill, B. J. Byrne, and P. D. Kessler, “Human mesenchymal stem cells differentiate to a cardiomyocyte phenotype in the adult murine heart,” Circulation, vol. 105, no. 1, pp. 93–98, 2002. View at: Publisher Site | Google Scholar
  110. A. P. Gee, S. Richman, A. Durett et al., “Multicenter cell processing for cardiovascular regenerative medicine applications: the Cardiovascular Cell Therapy Research Network (CCTRN) experience,” Cytotherapy, vol. 12, no. 5, pp. 684–691, 2010. View at: Publisher Site | Google Scholar
  111. B. Trachtenberg, D. L. Velazquez, A. R. Williams et al., “Rationale and design of the transendocardial injection of autologous human cells (bone marrow or mesenchymal) in chronic ischemic left ventricular dysfunction and heart failure secondary to myocardial infarction (TAC-HFT) trial: a randomized, double-blind, placebo-controlled study of safety and efficacy,” American Heart Journal, vol. 161, no. 3, pp. 487–493, 2011. View at: Publisher Site | Google Scholar
  112. J. M. Hare, J. H. Traverse, T. D. Henry et al., “A randomized, double-blind, placebo-controlled, dose-escalation study of intravenous adult human mesenchymal stem cells (prochymal) after acute myocardial infarction,” Journal of the American College of Cardiology, vol. 54, no. 24, pp. 2277–2286, 2009. View at: Publisher Site | Google Scholar
  113. S.-L. Chen, W.-W. Fang, F. Ye et al., “Effect on left ventricular function of intracoronary transplantation of autologous bone marrow mesenchymal stem cell in patients with acute myocardial infarction,” The American Journal of Cardiology, vol. 94, no. 1, pp. 92–95, 2004. View at: Publisher Site | Google Scholar
  114. K. H. Wu, B. Zhou, X. M. Mo et al., “Therapeutic potential of human umbilical cord-derived stem cells in ischemic diseases,” Transplantation Proceedings, vol. 39, no. 5, pp. 1620–1622, 2007. View at: Publisher Site | Google Scholar
  115. N. Berthelemy, H. Kerdjoudj, P. Schaaf et al., “O2 level controls hematopoietic circulating progenitor cells differentiation into endothelial or smooth muscle cells,” PLoS ONE, vol. 4, no. 5, Article ID e5514, 2009. View at: Publisher Site | Google Scholar
  116. M. Faustini, M. Bucco, T. Chlapanidas et al., “Nonexpanded mesenchymal stem cells for regenerative medicine: yield in stromal vascular fraction from adipose tissues,” Tissue Engineering Part C: Methods, vol. 16, no. 6, pp. 1515–1521, 2010. View at: Publisher Site | Google Scholar
  117. S. Kachgal and A. J. Putnam, “Mesenchymal stem cells from adipose and bone marrow promote angiogenesis via distinct cytokine and protease expression mechanisms,” Angiogenesis, vol. 14, no. 1, pp. 47–59, 2011. View at: Publisher Site | Google Scholar
  118. D. Kaigler, P. H. Krebsbach, P. J. Polverini, and D. J. Mooney, “Role of vascular endothelial growth factor in bone marrow stromal cell modulation of endothelial cells,” Tissue Engineering, vol. 9, no. 1, pp. 95–103, 2003. View at: Publisher Site | Google Scholar
  119. C. Sengenès, A. Miranville, M. Maumus, S. de Barros, R. Busse, and A. Bouloumié, “Chemotaxis and differentiation of human adipose tissue CD34+/CD31- progenitor cells: role of stromal derived factor-1 released by adipose tissue capillary endothelial cells,” Stem Cells, vol. 25, no. 9, pp. 2269–2276, 2007. View at: Publisher Site | Google Scholar
  120. F. Zhang, S. Tsai, K. Kato et al., “Transforming growth factor-β promotes recruitment of bone marrow cells and bone marrow-derived mesenchymal stem cells through stimulation of MCP-1 production in vascular smooth muscle cells,” The Journal of Biological Chemistry, vol. 284, no. 26, pp. 17564–17574, 2009. View at: Publisher Site | Google Scholar
  121. U.-M. Riegelsberger, A. Deten, C. Pösel et al., “Intravenous human umbilical cord blood transplantation for stroke: impact on infarct volume and caspase-3-dependent cell death in spontaneously hypertensive rats,” Experimental Neurology, vol. 227, no. 1, pp. 218–223, 2011. View at: Publisher Site | Google Scholar
  122. J. S. Lee, J. M. Hong, G. J. Moon, P. H. Lee, Y. H. Ahn, and O. Y. Bang, “A long-term follow-up study of intravenous autologous mesenchymal stem cell transplantation in patients with ischemic stroke,” Stem Cells, vol. 28, no. 6, pp. 1099–1106, 2010. View at: Publisher Site | Google Scholar
  123. Y. Jiang, W. Zhu, J. Zhu, L. Wu, G. Xu, and X. Liu, “Feasibility of delivering mesenchymal stem cells via catheter to the proximal end of the lesion artery in patients with stroke in the territory of the middle cerebral artery,” Cell Transplantation, vol. 22, no. 12, pp. 2291–2298, 2013. View at: Publisher Site | Google Scholar
  124. D. C. Hess, C. A. Sila, A. J. Furlan, L. R. Wechsler, J. A. Switzer, and R. W. Mays, “A double-blind placebo-controlled clinical evaluation of MultiStem for the treatment of ischemic stroke,” International Journal of Stroke, vol. 9, no. 3, pp. 381–386, 2014. View at: Publisher Site | Google Scholar
  125. S.-T. Lee, K. Chu, K.-H. Jung et al., “Slowed progression in models of Huntington disease by adipose stem cell transplantation,” Annals of Neurology, vol. 66, no. 5, pp. 671–681, 2009. View at: Publisher Site | Google Scholar
  126. T. Lopatina, N. Kalinina, M. Karagyaur et al., “Adipose-derived stem cells stimulate regeneration of peripheral nerves: BDNF secreted by these cells promotes nerve healing and axon growth de Novo,” PLoS ONE, vol. 6, no. 3, Article ID e17899, 2011. View at: Publisher Site | Google Scholar
  127. J. Alper, “Geron gets green light for human trial of ES cell-derived product,” Nature Biotechnology, vol. 27, no. 3, pp. 213–214, 2009. View at: Publisher Site | Google Scholar
  128. A. R. Chapman and C. C. Scala, “Evaluating the first-in-human clinical trial of a human embryonic stem cell-based therapy,” Kennedy Institute of Ethics Journal, vol. 22, no. 3, pp. 243–261, 2012. View at: Publisher Site | Google Scholar
  129. P. Bigini, P. Veglianese, G. Andriolo et al., “Intracerebroventricular administration of human umbilical cord blood cells delays disease progression in two murine models of motor neuron degeneration,” Rejuvenation Research, vol. 14, no. 6, pp. 623–639, 2011. View at: Publisher Site | Google Scholar
  130. N. K. Venkataramana, S. K. V. Kumar, S. Balaraju et al., “Open-labeled study of unilateral autologous bone-marrow-derived mesenchymal stem cell transplantation in Parkinson's disease,” Translational Research, vol. 155, no. 2, pp. 62–70, 2010. View at: Publisher Site | Google Scholar
  131. J. Y. Shin, H. J. Park, H. N. Kim et al., “Mesenchymal stem cells enhance autophagy and increase β-amyloid clearance in Alzheimer disease models,” Autophagy, vol. 10, no. 1, pp. 32–44, 2014. View at: Publisher Site | Google Scholar
  132. C. M. Lewis and M. Suzuki, “Therapeutic applications of mesenchymal stem cells for amyotrophic lateral sclerosis,” Stem Cell Research and Therapy, vol. 5, no. 2, article no. 32, 2014. View at: Publisher Site | Google Scholar
  133. N. de Isla, C. Huseltein, N. Jessel et al., “Introduction to tissue engineering and application for cartilage engineering,” Bio-Medical Materials and Engineering, vol. 20, no. 3-4, pp. 127–133, 2010. View at: Publisher Site | Google Scholar
  134. F. Mao, W.-R. Xu, H. Qian et al., “Immunosuppressive effects of mesenchymal stem cells in collagen-induced mouse arthritis,” Inflammation Research, vol. 59, no. 3, pp. 219–225, 2010. View at: Publisher Site | Google Scholar
  135. J. F. Stoltz, Ed., Mechanobiology: Cartilage and Chondrocyte, IOS Press, Washington, DC, USA, 2006.
  136. J. A. Buckwalter, M. Lotz, and J. F. Stoltz, Osteoarthritis, Inflammation, and Degradation: A Continuum, IOS Press, Amsterdam, The Netherlands, 2007.
  137. A. Arthur, A. Zannettino, and S. Gronthos, “The therapeutic applications of multipotential mesenchymal/stromal stem cells in skeletal tissue repair,” Journal of Cellular Physiology, vol. 218, no. 2, pp. 237–245, 2009. View at: Publisher Site | Google Scholar
  138. S. P. Bruder, A. A. Kurth, M. Shea, W. C. Hayes, N. Jaiswal, and S. Kadiyala, “Bone regeneration by implantation of purified, culture-expanded human mesenchymal stem cells,” Journal of Orthopaedic Research, vol. 16, no. 2, pp. 155–162, 1998. View at: Publisher Site | Google Scholar
  139. S. Wakitani, T. Mitsuoka, N. Nakamura, Y. Toritsuka, Y. Nakamura, and S. Horibe, “Autologous bone marrow stromal cell transplantation for repair of full-thickness articular cartilage defects in human patellae: two case reports,” Cell Transplantation, vol. 13, no. 5, pp. 595–600, 2004. View at: Publisher Site | Google Scholar
  140. C. Chen, D. T. Tambe, L. Deng, and L. Yang, “Biomechanical properties and mechanobiology of the articular chondrocyte,” The American Journal of Physiology—Cell Physiology, vol. 305, no. 12, pp. C1202–C1208, 2013. View at: Publisher Site | Google Scholar
  141. R. E. Wilusz, J. Sanchez-Adams, and F. Guilak, “The structure and function of the pericellular matrix of articular cartilage,” Matrix Biology, vol. 39, pp. 25–32, 2014. View at: Publisher Site | Google Scholar
  142. H. A. Breinan, T. Minas, H.-P. Hsu, S. Nehrer, C. B. Sledge, and M. Spector, “Effect of cultured autologous chondrocytes on repair of chondral defects in a canine model,” The Journal of Bone & Joint Surgery Series A, vol. 79, no. 10, pp. 1439–1451, 1997. View at: Google Scholar
  143. B. Schmitt, J. Ringe, T. Häupl et al., “BMP2 initiates chondrogenic lineage development of adult human mesenchymal stem cells in high-density culture,” Differentiation, vol. 71, no. 9-10, pp. 567–577, 2003. View at: Publisher Site | Google Scholar
  144. S. Wakitani, K. Imoto, T. Yamamoto, M. Saito, N. Murata, and M. Yoneda, “Human autologous culture expanded bone marrow-mesenchymal cell transplantation for repair of cartilage defects in osteoarthritic knees,” Osteoarthritis and Cartilage, vol. 10, no. 3, pp. 199–206, 2002. View at: Publisher Site | Google Scholar
  145. M. Brittberg, A. Lindahl, A. Nilsson, C. Ohlsson, O. Isaksson, and L. Peterson, “Treatment of deep cartilage defects in the knee with autologous chondrocyte transplantation,” The New England Journal of Medicine, vol. 331, no. 14, pp. 889–895, 1994. View at: Publisher Site | Google Scholar
  146. C. Huselstein, P. Netter, N. de Isla et al., “Mechanobiology, chondrocyte and cartilage,” Bio-Medical Materials and Engineering, vol. 18, no. 4-5, pp. 213–220, 2008. View at: Publisher Site | Google Scholar
  147. P. Angele, J. U. Yoo, C. Smith et al., “Cyclic hydrostatic pressure enhances the chondrogenic phenotype of human mesenchymal progenitor cells differentiated in vitro,” Journal of Orthopaedic Research, vol. 21, no. 3, pp. 451–457, 2003. View at: Publisher Site | Google Scholar
  148. F. Barry, R. E. Boynton, B. Liu, and J. M. Murphy, “Chondrogenic differentiation of mesenchymal stem cells from bone marrow: differentiation-dependent gene expression of matrix components,” Experimental Cell Research, vol. 268, no. 2, pp. 189–200, 2001. View at: Publisher Site | Google Scholar
  149. J. J. Campbell, D. A. Lee, and D. L. Bader, “Dynamic compressive strain influences chondrogenic gene expression in human mesenchymal stem cells,” Biorheology, vol. 43, no. 3-4, pp. 455–470, 2006. View at: Google Scholar
  150. L. de Girolamo, S. Lopa, E. Arrigoni, M. F. Sartori, F. W. B. Preis, and A. T. Brini, “Human adipose-derived stem cells isolated from young and elderly women: their differentiation potential and scaffold interaction during in vitro osteoblastic differentiation,” Cytotherapy, vol. 11, no. 6, pp. 793–803, 2009. View at: Publisher Site | Google Scholar
  151. K. Hiraoka, S. Grogan, T. Olee, and M. Lotz, “Mesenchymal progenitor cells in adult human articular cartilage,” Biorheology, vol. 43, no. 3-4, pp. 447–454, 2006. View at: Google Scholar
  152. J. I. Huang, N. Kazmi, M. M. Durbhakula, T. M. Hering, J. U. Yoo, and B. Johnstone, “Chondrogenic potential of progenitor cells derived from human bone marrow and adipose tissue: a patient-matched comparison,” Journal of Orthopaedic Research, vol. 23, no. 6, pp. 1383–1389, 2005. View at: Publisher Site | Google Scholar
  153. J.-F. Stoltz, C. Huselstein, J. Schiavi et al., “Human stem cells and articular cartilage tissue engineering,” Current Pharmaceutical Biotechnology, vol. 13, no. 15, pp. 2682–2691, 2012. View at: Publisher Site | Google Scholar
  154. C.-Y. Fong, A. Subramanian, K. Gauthaman et al., “Human umbilical cord Wharton’s jelly stem cells undergo enhanced chondrogenic differentiation when grown on nanofibrous scaffolds and in a sequential two-stage culture medium environment,” Stem Cell Reviews and Reports, vol. 8, no. 1, pp. 195–209, 2012. View at: Publisher Site | Google Scholar
  155. X. Chen, F. Zhang, X. He et al., “Chondrogenic differentiation of umbilical cord-derived mesenchymal stem cells in type I collagen-hydrogel for cartilage engineering,” Injury, vol. 44, no. 4, pp. 540–549, 2013. View at: Publisher Site | Google Scholar
  156. S. Liu, K. D. Hou, M. Yuan et al., “Characteristics of mesenchymal stem cells derived from Wharton's jelly of human umbilical cord and for fabrication of non-scaffold tissue-engineered cartilage,” Journal of Bioscience and Bioengineering, vol. 117, no. 2, pp. 229–235, 2014. View at: Publisher Site | Google Scholar
  157. S. Ciavarella, F. Dammacco, M. de Matteo, G. Loverro, and F. Silvestris, “Umbilical cord mesenchymal stem cells: role of regulatory genes in their differentiation to osteoblasts,” Stem Cells and Development, vol. 18, no. 8, pp. 1211–1220, 2009. View at: Publisher Site | Google Scholar
  158. K. L. Wong, K. B. L. Lee, B. C. Tai, P. Law, E. H. Lee, and J. H. P. Hui, “Injectable cultured bone marrow-derived mesenchymal stem cells in varus knees with cartilage defects undergoing high tibial osteotomy: a prospective, randomized controlled clinical trial with 2 years' follow-up,” Arthroscopy, vol. 29, no. 12, pp. 2020–2028, 2013. View at: Publisher Site | Google Scholar
  159. C. H. Jo, Y. G. Lee, W. H. Shin et al., “Intra-articular injection of mesenchymal stem cells for the treatment of osteoarthritis of the knee: a proof-of-concept clinical trial,” Stem Cells, vol. 32, no. 5, pp. 1254–1266, 2014. View at: Publisher Site | Google Scholar
  160. A. Vega, M. A. Martín-Ferrero, F. Del Canto et al., “Treatment of knee osteoarthritis with allogeneic bone marrow mesenchymal stem cells: a randomized controlled trial,” Transplantation, 2015. View at: Publisher Site | Google Scholar
  161. M. Dubský, A. Jirkovská, R. Bem et al., “Comparison of the effect of stem cell therapy and percutaneous transluminal angioplasty on diabetic foot disease in patients with critical limb ischemia,” Cytotherapy, vol. 16, no. 12, pp. 1733–1738, 2014. View at: Publisher Site | Google Scholar
  162. R. Subrammaniyan, J. Amalorpavanathan, R. Shankar et al., “Our experience of application of Autologous Bone Marrow Stem Cells in critical limb ischemia in six diabetic patients—a five-year follow-up,” Journal of Stem cells & Regenerative Medicine, vol. 7, no. 2, p. 97, 2011. View at: Google Scholar
  163. V. Sordi, M. L. Malosio, F. Marchesi et al., “Bone marrow mesenchymal stem cells express a restricted set of functionally active chemokine receptors capable of promoting migration to pancreatic islets,” Blood, vol. 106, no. 2, pp. 419–427, 2005. View at: Publisher Site | Google Scholar
  164. A. G. Tzakis, C. Ricordi, R. Alejandro et al., “Pancreatic islet transplantation after upper abdominal exenteration and liver replacement,” The Lancet, vol. 336, no. 8712, pp. 402–405, 1990. View at: Publisher Site | Google Scholar
  165. A. M. J. Shapiro, J. R. T. Lakey, E. A. Ryan et al., “Islet transplantation in seven patients with type 1 diabetes mellitus using a glucocorticoid-free immunosuppressive regimen,” The New England Journal of Medicine, vol. 343, no. 4, pp. 230–238, 2000. View at: Publisher Site | Google Scholar
  166. N. C. Close, B. J. Hering, and T. L. Eggerman, “Results from the inaugural year of the Collaborative Islet Transplant Registry,” Transplantation Proceedings, vol. 37, no. 2, pp. 1305–1308, 2005. View at: Publisher Site | Google Scholar
  167. A. M. J. Shapiro, J. R. T. Lakey, B. W. Paty, P. A. Senior, D. L. Bigam, and E. A. Ryan, “Strategic opportunities in clinical islet transplantation,” Transplantation, vol. 79, no. 10, pp. 1304–1307, 2005. View at: Publisher Site | Google Scholar
  168. P. Czubak, A. Bojarska-Junak, J. Tabarkiewicz, and L. Putowski, “A modified method of insulin producing cells’ generation from bone marrow-derived mesenchymal stem cells,” Journal of Diabetes Research, vol. 2014, Article ID 628591, 7 pages, 2014. View at: Publisher Site | Google Scholar
  169. L. Khorsandi, F. Nejad-Dehbashi, A. Ahangarpour, and M. Hashemitabar, “Three-dimensional differentiation of bone marrow-derived mesenchymal stem cells into insulin-producing cells,” Tissue and Cell, vol. 47, no. 1, pp. 66–72, 2015. View at: Publisher Site | Google Scholar
  170. S. Kadam, S. Muthyala, P. Nair, and R. Bhonde, “Human placenta-derived mesenchymal stem cells and islet-like cell clusters generated from these cells as a novel source for stem cell therapy in diabetes,” The Review of Diabetic Studies, vol. 7, no. 2, pp. 168–182, 2010. View at: Google Scholar
  171. H. Qu, X. Liu, Y. Ni et al., “Laminin 411 acts as a potent inducer of umbilical cord mesenchymal stem cell differentiation into insulin-producing cells,” Journal of Translational Medicine, vol. 12, no. 1, article 135, 2014. View at: Publisher Site | Google Scholar
  172. P.-J. Tsai, H.-S. Wang, G.-J. Lin et al., “Undifferentiated Wharton's jelly mesenchymal stem cell transplantation induces insulin-producing cell differentiation and suppression of T cell-mediated autoimmunity in non-obese diabetic mice,” Cell Transplantation, 2014. View at: Publisher Site | Google Scholar
  173. K. A. D'Amour, A. D. Agulnick, S. Eliazer, O. G. Kelly, E. Kroon, and E. E. Baetge, “Efficient differentiation of human embryonic stem cells to definitive endoderm,” Nature Biotechnology, vol. 23, no. 12, pp. 1534–1541, 2005. View at: Publisher Site | Google Scholar
  174. S. Chen, M. Borowiak, J. L. Fox et al., “A small molecule that directs differentiation of human ESCs into the pancreatic lineage,” Nature Chemical Biology, vol. 5, no. 4, pp. 258–265, 2009. View at: Publisher Site | Google Scholar
  175. E. Kroon, L. A. Martinson, K. Kadoya et al., “Pancreatic endoderm derived from human embryonic stem cells generates glucose-responsive insulin-secreting cells in vivo,” Nature Biotechnology, vol. 26, no. 4, pp. 443–452, 2008. View at: Publisher Site | Google Scholar
  176. K. Tateishi, J. He, O. Taranova, G. Liang, A. C. D'Alessio, and Y. Zhang, “Generation of insulin-secreting islet-like clusters from human skin fibroblasts,” Journal of Biological Chemistry, vol. 283, no. 46, pp. 31601–31607, 2008. View at: Publisher Site | Google Scholar
  177. T. Thatava, T. J. Nelson, R. Edukulla et al., “Indolactam V/GLP-1-mediated differentiation of human iPS cells into glucose-responsive insulin-secreting progeny,” Gene Therapy, vol. 18, no. 3, pp. 283–293, 2011. View at: Publisher Site | Google Scholar
  178. R. Jiang, Z. Han, G. Zhuo et al., “Transplantation of placenta-derived mesenchymal stem cells in type 2 diabetes: a pilot study,” Frontiers of Medicine in China, vol. 5, no. 1, pp. 94–100, 2011. View at: Publisher Site | Google Scholar
  179. J. Hu, X. Yu, Z. Wang et al., “Long term effects of the implantation of Wharton's jelly-derived mesenchymal stem cells from the umbilical cord for newly-onset type 1 diabetes mellitus,” Endocrine Journal, vol. 60, no. 3, pp. 347–357, 2013. View at: Publisher Site | Google Scholar
  180. D. Kong, X. Zhuang, D. Wang et al., “Umbilical cord mesenchymal stem cell transfusion ameliorated hyperglycemia in patients with type 2 diabetes mellitus,” Clinical Laboratory, vol. 60, no. 12, pp. 1969–1976, 2014. View at: Google Scholar
  181. P. Carlsson, E. Schwarcz, O. Korsgren, and K. Le Blanc, “Preserved β-cell function in type 1 diabetes by mesenchymal stromal cells,” Diabetes, vol. 64, no. 2, pp. 587–592, 2015. View at: Publisher Site | Google Scholar
  182. S. T. Rashid, S. Corbineau, N. Hannan et al., “Modeling inherited metabolic disorders of the liver using human induced pluripotent stem cells,” Journal of Clinical Investigation, vol. 120, no. 9, pp. 3127–3136, 2010. View at: Publisher Site | Google Scholar
  183. L. Zhang, J.-S. Ye, V. Decot, J.-F. Stoltz, and N. de Isla, “Research on stem cells as candidates to be differentiated into hepatocytes,” Bio-Medical Materials and Engineering, vol. 22, no. 1–3, pp. 105–111, 2012. View at: Publisher Site | Google Scholar
  184. Q. Zhao, H. Ren, X. Li et al., “Differentiation of human umbilical cord mesenchymal stromal cells into low immunogenic hepatocyte-like cells,” Cytotherapy, vol. 11, no. 4, pp. 414–426, 2009. View at: Publisher Site | Google Scholar
  185. T. S. Ramasamy, J. S. L. Yu, C. Selden, H. Hodgson, and W. Cui, “Application of three-dimensional culture conditions to human embryonic stem cell-derived definitive endoderm cells enhances hepatocyte differentiation and functionality,” Tissue Engineering Part A, vol. 19, no. 3-4, pp. 360–367, 2013. View at: Publisher Site | Google Scholar
  186. J. Jozefczuk, A. Prigione, L. Chavez, and J. Adjaye, “Comparative analysis of human embryonic stem cell and induced pluripotent stem cell-derived hepatocyte-like cells reveals current drawbacks and possible strategies for improved differentiation,” Stem Cells and Development, vol. 20, no. 7, pp. 1259–1275, 2011. View at: Publisher Site | Google Scholar
  187. K. Si-Tayeb, F. K. Noto, M. Nagaoka et al., “Highly efficient generation of human hepatocyte-like cells from induced pluripotent stem cells,” Hepatology, vol. 51, no. 1, pp. 297–305, 2010. View at: Publisher Site | Google Scholar
  188. M. Mohamadnejad, K. Alimoghaddam, M. Bagheri et al., “Randomized placebo-controlled trial of mesenchymal stem cell transplantation in decompensated cirrhosis,” Liver International, vol. 33, no. 10, pp. 1490–1496, 2013. View at: Publisher Site | Google Scholar
  189. L. Wang, J. Li, H. Liu et al., “A pilot study of umbilical cord-derived mesenchymal stem cell transfusion in patients with primary biliary cirrhosis,” Journal of Gastroenterology and Hepatology, vol. 28, no. 1, pp. 85–92, 2013. View at: Publisher Site | Google Scholar
  190. M. Shi, Z. Zhang, R. Xu et al., “Human mesenchymal stem cell transfusion is safe and improves liver function in acute-on-chronic liver failure patients,” Stem Cells Translational Medicine, vol. 1, no. 10, pp. 725–731, 2012. View at: Publisher Site | Google Scholar
  191. M.-E. M. Amer, S. Z. El-Sayed, W. A. El-Kheir et al., “Clinical and laboratory evaluation of patients with end-stage liver cell failure injected with bone marrow-derived hepatocyte-like cells,” European Journal of Gastroenterology & Hepatology, vol. 23, no. 10, pp. 936–941, 2011. View at: Publisher Site | Google Scholar
  192. A. Atala, S. B. Bauer, S. Soker, J. J. Yoo, and A. B. Retik, “Tissue-engineered autologous bladders for patients needing cystoplasty,” The Lancet, vol. 367, no. 9518, pp. 1241–1246, 2006. View at: Publisher Site | Google Scholar
  193. L. Ma, Y. Yang, S. C. Sikka et al., “Adipose tissue-derived stem cell-seeded small intestinal submucosa for tunica albuginea grafting and reconstruction,” Proceedings of the National Academy of Sciences of the United States of America, vol. 109, no. 6, pp. 2090–2095, 2012. View at: Publisher Site | Google Scholar
  194. G. Nolazco, I. Kovanecz, D. Vernet et al., “Effect of muscle-derived stem cells on the restoration of corpora cavernosa smooth muscle and erectile function in the aged rat,” BJU International, vol. 101, no. 9, pp. 1156–1164, 2008. View at: Publisher Site | Google Scholar
  195. J. Y. Bahk, J. H. Jung, H. Han, S. K. Min, and Y. S. Lee, “Treatment of diabetic impotence with umbilical cord blood stem cell intracavernosal transplant: preliminary report of 7 cases,” Experimental and Clinical Transplantation, vol. 8, no. 2, pp. 150–160, 2010. View at: Google Scholar
  196. F. Castiglione, P. Hedlund, F. van der Aa et al., “Intratunical injection of human adipose tissue-derived stem cells prevents fibrosis and is associated with improved erectile function in a rat model of Peyronie's disease,” European Urology, vol. 63, no. 3, pp. 551–560, 2013. View at: Publisher Site | Google Scholar
  197. T. K. Ng, V. R. Fortino, D. Pelaez, and H. S. Cheung, “Progress of mesenchymal stem cell therapy for neural and retinal diseases,” World Journal of Stem Cells, vol. 6, no. 2, pp. 111–119, 2014. View at: Publisher Site | Google Scholar
  198. A. Tzameret, I. Sher, M. Belkin et al., “Transplantation of human bone marrow mesenchymal stem cells as a thin subretinal layer ameliorates retinal degeneration in a rat model of retinal dystrophy,” Experimental Eye Research, vol. 118, pp. 135–144, 2014. View at: Publisher Site | Google Scholar
  199. Y. Hu, H. B. Tan, X. M. Wang, H. Rong, and H. P. Cui, “Bone marrow mesenchymal stem cells protect against retinal ganglion cell loss in aged rats with glaucoma,” Clinical Interventions in Aging, vol. 8, pp. 1467–1470, 2013. View at: Publisher Site | Google Scholar
  200. L. Ronzoni, P. Bonara, D. Rusconi, C. Frugoni, I. Libani, and M. D. Cappellini, “Erythroid differentiation and maturation from peripheral CD34+ cells in liquid culture: cellular and molecular characterization,” Blood Cells, Molecules, and Diseases, vol. 40, no. 2, pp. 148–155, 2008. View at: Publisher Site | Google Scholar
  201. E. Olivier, C. Qiu, and E. E. Bouhassira, “Novel, high-yield red blood cell production methods from CD34-positive cells derived from human embryonic stem, yolk sac, fetal liver, cord blood, and peripheral blood,” Stem Cells Translational Medicine, vol. 1, no. 8, pp. 604–614, 2012. View at: Publisher Site | Google Scholar
  202. F. Ma, Y. Ebihara, K. Umeda et al., “Generation of functional erythrocytes from human embryonic stem cell-derived definitive hematopoiesis,” Proceedings of the National Academy of Sciences of the United States of America, vol. 105, no. 35, pp. 13087–13092, 2008. View at: Publisher Site | Google Scholar
  203. Y. Ebihara, F. Ma, and K. Tsuji, “Generation of red blood cells from human embryonic/induced pluripotent stem cells for blood transfusion,” International Journal of Hematology, vol. 95, no. 6, pp. 610–616, 2012. View at: Publisher Site | Google Scholar
  204. C.-T. Yang, A. French, P. A. Goh et al., “Human induced pluripotent stem cell derived erythroblasts can undergo definitive erythropoiesis and co-express gamma and beta globins,” British Journal of Haematology, vol. 166, no. 3, pp. 435–448, 2014. View at: Publisher Site | Google Scholar
  205. A. Atala, “Engineering organs,” Current Opinion in Biotechnology, vol. 20, no. 5, pp. 575–592, 2009. View at: Google Scholar
  206. G. Orlando, P. Baptista, M. Birchall et al., “Regenerative medicine as applied to solid organ transplantation: current status and future challenges,” Transplant International, vol. 24, no. 3, pp. 223–232, 2011. View at: Publisher Site | Google Scholar
  207. S. F. Badylak, D. Taylor, and K. Uygun, “Whole-organ tissue engineering: decellularization and recellularization of three-dimensional matrix scaffolds,” Annual Review of Biomedical Engineering, vol. 13, pp. 27–53, 2011. View at: Publisher Site | Google Scholar
  208. P. M. Baptista, G. Orlando, S.-H. Mirmalek-Sani, M. Siddiqui, A. Atala, and S. Soker, “Whole organ decellularization—a tool for bioscaffold fabrication and organ bioengineering,” in Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC '09), pp. 6526–6529, 2009. View at: Google Scholar
  209. S. V. Murphy and A. Atala, “Organ engineering—combining stem cells, biomaterials, and bioreactors to produce bioengineered organs for transplantation,” BioEssays, vol. 35, no. 3, pp. 163–172, 2013. View at: Publisher Site | Google Scholar
  210. M. E. Scarritt, N. C. Pashos, and B. A. Bunnell, “A review of cellularization strategies for tissue engineering of whole organs,” Frontiers in Bioengineering and Biotechnology, vol. 3, article 43, 2015. View at: Google Scholar
  211. A. Mathur and J. F. Martin, “Stem cells and repair of the heart,” The Lancet, vol. 364, no. 9429, pp. 183–192, 2004. View at: Publisher Site | Google Scholar
  212. H. C. Ott, T. S. Matthiesen, S.-K. Goh et al., “Perfusion-decellularized matrix: using nature's platform to engineer a bioartificial heart,” Nature Medicine, vol. 14, no. 2, pp. 213–221, 2008. View at: Publisher Site | Google Scholar
  213. A. A. Khan, S. K. Vishwakarma, A. Bardia, and J. Venkateshwarulu, “Repopulation of decellularized whole organ scaffold using stem cells: an emerging technology for the development of neo-organ,” Journal of Artificial Organs, vol. 17, no. 4, pp. 291–300, 2014. View at: Publisher Site | Google Scholar
  214. J. M. Singelyn and K. L. Christman, “Injectable materials for the treatment of myocardial infarction and heart failure: the promise of decellularized matrices,” Journal of Cardiovascular Translational Research, vol. 3, no. 5, pp. 478–486, 2010. View at: Publisher Site | Google Scholar
  215. T. Ota, T. W. Gilbert, S. F. Badylak, D. Schwartzman, and M. A. Zenati, “Electromechanical characterization of a tissue-engineered myocardial patch derived from extracellular matrix,” Journal of Thoracic and Cardiovascular Surgery, vol. 133, no. 4, pp. 979–985, 2007. View at: Publisher Site | Google Scholar
  216. I. A. Potapova, S. V. Doronin, D. J. Kelly et al., “Enhanced recovery of mechanical function in the canine heart by seeding an extracellular matrix patch with mesenchymal stem cells committed to a cardiac lineage,” The American Journal of Physiology—Heart and Circulatory Physiology, vol. 295, no. 6, pp. H2257–H2263, 2008. View at: Publisher Site | Google Scholar
  217. E. Martinod, A. Seguin, M. Holder-Espinasse et al., “Tracheal regeneration following tracheal replacement with an allogenic aorta,” Annals of Thoracic Surgery, vol. 79, no. 3, pp. 942–948, 2005. View at: Publisher Site | Google Scholar
  218. D. M. Radu, A. Seguin, P. Bruneval, A. F. Legendre, A. Carpentier, and E. Martinod, “Bronchial replacement with arterial allografts,” Annals of Thoracic Surgery, vol. 90, no. 1, pp. 252–258, 2010. View at: Publisher Site | Google Scholar
  219. G. M. Roomans, “Tissue engineering and the use of stem/progenitor cells for airway epithelium repair,” European Cells & Materials, vol. 19, pp. 284–299, 2010. View at: Google Scholar
  220. A. Seguin, D. Radu, M. Holder-Espinasse et al., “Tracheal replacement with cryopreserved, decellularized, or glutaraldehyde-treated aortic allografts,” Annals of Thoracic Surgery, vol. 87, no. 3, pp. 861–867, 2009. View at: Publisher Site | Google Scholar
  221. T. H. Petersen, E. A. Calle, L. Zhao et al., “Tissue-engineered lungs for in vivo implantation,” Science, vol. 329, no. 5991, pp. 538–541, 2010. View at: Publisher Site | Google Scholar
  222. D. A. Chistiakov, “Endogenous and exogenous stem cells: a role in lung repair and use in airway tissue engineering and transplantation,” Journal of Biomedical Science, vol. 17, no. 1, article 92, 2010. View at: Publisher Site | Google Scholar
  223. H. A. Chapman, “Toward lung regeneration,” The New England Journal of Medicine, vol. 364, no. 19, pp. 1867–1868, 2011. View at: Publisher Site | Google Scholar
  224. J. Martin, K. Helm, P. Ruegg, M. Varella-Garcia, E. Burnham, and S. Majka, “Adult lung side population cells have mesenchymal stem cell potential,” Cytotherapy, vol. 10, no. 2, pp. 140–151, 2008. View at: Publisher Site | Google Scholar
  225. L. Jarvinen, L. Badri, S. Wettlaufer et al., “Lung resident mesenchymal stem cells isolated from human lung allografts inhibit T cell proliferation via a soluble mediator,” The Journal of Immunology, vol. 181, no. 6, pp. 4389–4396, 2008. View at: Google Scholar
  226. X. Gong, Z. Sun, D. Cui et al., “Isolation and characterization of lung resident mesenchymal stem cells capable of differentiating into alveolar epithelial type II cells,” Cell Biology International, vol. 38, no. 4, pp. 405–411, 2014. View at: Publisher Site | Google Scholar
  227. K. Chow, J. P. Fessel, Kaoriihida-Stansbury et al., “Dysfunctional resident lung mesenchymal stem cells contribute to pulmonary microvascular remodeling,” Pulmonary Circulation, vol. 3, no. 1, pp. 31–49, 2013. View at: Publisher Site | Google Scholar
  228. K. M. Antoniou, H. A. Papadaki, G. Soufla et al., “Investigation of bone marrow mesenchymal stem cells (BM MSCs) involvement in idiopathic pulmonary fibrosis (IPF),” Respiratory Medicine, vol. 104, no. 10, pp. 1535–1542, 2010. View at: Publisher Site | Google Scholar
  229. Y. Zhang, S. Liao, M. Yang et al., “Improved cell survival and paracrine capacity of human embryonic stem cell-derived mesenchymal stem cells promote therapeutic potential for pulmonary arterial hypertension,” Cell Transplantation, vol. 21, no. 10, pp. 2225–2239, 2012. View at: Publisher Site | Google Scholar
  230. K. D. Liu, J. G. Wilson, H. Zhuo et al., “Design and implementation of the START (STem cells for ARDS Treatment) trial, a phase 1/2 trial of human mesenchymal stem/stromal cells for the treatment of moderate-severe acute respiratory distress syndrome,” Annals of Intensive Care, vol. 4, article 22, 2014. View at: Publisher Site | Google Scholar
  231. J. G. Wilson, K. D. Liu, H. Zhuo et al., “Mesenchymal stem (stromal) cells for treatment of ARDS: a phase 1 clinical trial,” The Lancet Respiratory Medicine, vol. 3, no. 1, pp. 24–32, 2015. View at: Publisher Site | Google Scholar
  232. H. C. Ott, B. Clippinger, C. Conrad et al., “Regeneration and orthotopic transplantation of a bioartificial lung,” Nature Medicine, vol. 16, no. 8, pp. 927–933, 2010. View at: Publisher Site | Google Scholar
  233. J. E. Nichols, J. Niles, M. Riddle et al., “Production and assessment of decellularized pig and human lung scaffolds,” Tissue Engineering Part A, vol. 19, no. 17-18, pp. 2045–2062, 2013. View at: Publisher Site | Google Scholar
  234. D. E. Wagner, N. R. Bonenfant, D. Sokocevic et al., “Three-dimensional scaffolds of acellular human and porcine lungs for high throughput studies of lung disease and regeneration,” Biomaterials, vol. 35, no. 9, pp. 2664–2679, 2014. View at: Publisher Site | Google Scholar
  235. R. W. Bonvillain, S. Danchuk, D. E. Sullivan et al., “A nonhuman primate model of lung regeneration: detergent-mediated decellularization and initial in vitro recellularization with mesenchymal stem cells,” Tissue Engineering—Part A, vol. 18, no. 23-24, pp. 2437–2452, 2012. View at: Publisher Site | Google Scholar
  236. J. Cortiella, J. Niles, A. Cantu et al., “Influence of acellular natural lung matrix on murine embryonic stem cell differentiation and tissue formation,” Tissue Engineering Part A, vol. 16, no. 8, pp. 2565–2580, 2010. View at: Publisher Site | Google Scholar
  237. S. Lecht, C. T. Stabler, A. L. Rylander et al., “Enhanced reseeding of decellularized rodent lungs with mouse embryonic stem cells,” Biomaterials, vol. 35, no. 10, pp. 3252–3262, 2014. View at: Publisher Site | Google Scholar
  238. T. Tsuchiya, A. Sivarapatna, K. Rocco, A. Nanashima, T. Nagayasu, and L. E. Niklason, “Future prospects for tissue engineered lung transplantation: decellularization and recellularization-based whole lung regeneration,” Organogenesis, vol. 10, no. 2, pp. 196–207, 2014. View at: Google Scholar
  239. A. Soto-Gutierrez, L. Zhang, C. Medberry et al., “A whole-organ regenerative medicine approach for liver replacement,” Tissue Engineering, Part C: Methods, vol. 17, no. 6, pp. 677–686, 2011. View at: Publisher Site | Google Scholar
  240. H. Yagi, K. Fukumitsu, K. Fukuda et al., “Human-scale whole-organ bioengineering for liver transplantation: a regenerative medicine approach,” Cell Transplantation, vol. 22, no. 2, pp. 231–242, 2013. View at: Publisher Site | Google Scholar
  241. J.-S. Ye, J.-F. Stoltz, N. de Isla, Y. Liu, Y.-F. Yin, and L. Zhang, “An approach to preparing decellularized whole liver organ scaffold in rat,” Bio-Medical Materials and Engineering, vol. 25, no. 1, supplement, pp. 159–166, 2015. View at: Publisher Site | Google Scholar
  242. W.-C. Jiang, Y.-H. Cheng, M.-H. Yen, Y. Chang, V. W. Yang, and O. K. Lee, “Cryo-chemical decellularization of the whole liver for mesenchymal stem cells-based functional hepatic tissue engineering,” Biomaterials, vol. 35, no. 11, pp. 3607–3617, 2014. View at: Publisher Site | Google Scholar
  243. R. Ji, N. Zhang, N. You et al., “The differentiation of MSCs into functional hepatocyte-like cells in a liver biomatrix scaffold and their transplantation into liver-fibrotic mice,” Biomaterials, vol. 33, no. 35, pp. 8995–9008, 2012. View at: Publisher Site | Google Scholar
  244. L. Behr, M. Hekmati, A. Lucchini et al., “Evaluation of the effect of autologous mesenchymal stem cell injection in a large-animal model of bilateral kidney ischaemia reperfusion injury,” Cell Proliferation, vol. 42, no. 3, pp. 284–297, 2009. View at: Publisher Site | Google Scholar
  245. L. Behr, M. Hekmati, G. Fromont et al., “Intra renal arterial injection of autologous mesenchymal stem cells in an ovine model in the postischemic kidney,” Nephron Physiology, vol. 107, no. 3, pp. p65–p76, 2007. View at: Publisher Site | Google Scholar
  246. S. K. Nigam, W. Wu, and K. T. Bush, “Organogenesis forum lecture: in vitro kidney development, tissue engineering and systems biology,” Organogenesis, vol. 4, no. 3, pp. 137–143, 2008. View at: Google Scholar
  247. E. Rosines, K. Johkura, X. Zhang et al., “Constructing kidney-like tissues from cells based on programs for organ development: toward a method of in vitro tissue engineering of the kidney,” Tissue Engineering, Part A, vol. 16, no. 8, pp. 2441–2455, 2010. View at: Publisher Site | Google Scholar
  248. E. A. Ross, M. J. Williams, T. Hamazaki et al., “Embryonic stem cells proliferate and differentiate when seeded into kidney scaffolds,” Journal of the American Society of Nephrology, vol. 20, no. 11, pp. 2338–2347, 2009. View at: Publisher Site | Google Scholar
  249. K. H. Nakayama, C. A. Batchelder, C. I. Lee, and A. F. Tarantal, “Decellularized rhesus monkey kidney as a three-dimensional scaffold for renal tissue engineering,” Tissue Engineering Part A, vol. 16, no. 7, pp. 2207–2216, 2010. View at: Publisher Site | Google Scholar
  250. F. Tasnim, R. Deng, M. Hu et al., “Achievements and challenges in bioartificial kidney development,” Fibrogenesis & Tissue Repair, vol. 3, no. 14, 2010. View at: Publisher Site | Google Scholar
  251. S. R. Baglio, D. M. Pegtel, and N. Baldini, “Mesenchymal stem cell secreted vesicles provide novel opportunities in (stem) cell-free therapy,” Frontiers in Physiology, vol. 3, article 359, 2012. View at: Publisher Site | Google Scholar
  252. R. C. Lai, R. W. Y. Yeo, and S. K. Lim, “Mesenchymal stem cell exosomes,” Seminars in Cell & Developmental Biology, vol. 40, pp. 82–88, 2015. View at: Google Scholar
  253. S. E. Haynesworth, M. A. Baber, and A. I. Caplan, “Cytokine expression by human marrow-derived mesenchymal progenitor cells in vitro: Effects of dexamethasone and IL-1α,” Journal of Cellular Physiology, vol. 166, no. 3, pp. 585–592, 1996. View at: Publisher Site | Google Scholar
  254. B. Yu, X. Zhang, and X. Li, “Exosomes derived from mesenchymal stem cells,” International Journal of Molecular Sciences, vol. 15, no. 3, pp. 4142–4157, 2014. View at: Publisher Site | Google Scholar
  255. J. R. Lavoie and M. Rosu-Myles, “Uncovering the secretes of mesenchymal stem cells,” Biochimie, vol. 95, no. 12, pp. 2212–2221, 2013. View at: Publisher Site | Google Scholar
  256. K. C. Vallabhaneni, P. Penfornis, S. Dhule et al., “Extracellular vesicles from bone marrow mesenchymal stem/stromal cells transport tumor regulatory microRNA, proteins, and metabolites,” Oncotarget, vol. 6, no. 7, pp. 4953–4967, 2015. View at: Google Scholar
  257. T. Kinnaird, E. Stabile, M. S. Burnett et al., “Marrow-derived stromal cells express genes encoding a broad spectrum of arteriogenic cytokines and promote in vitro and in vivo arteriogenesis through paracrine mechanisms,” Circulation Research, vol. 94, no. 5, pp. 678–685, 2004. View at: Publisher Site | Google Scholar
  258. M. Gnecchi, H. He, N. Noiseux et al., “Evidence supporting paracrine hypothesis for Akt-modified mesenchymal stem cell-mediated cardiac protection and functional improvement,” The FASEB Journal, vol. 20, no. 6, pp. 661–669, 2006. View at: Publisher Site | Google Scholar
  259. A. Shabbir, A. Coz, L. Rodriguez, M. Salgado, and E. Badiavas, “Mesenchymal stem cell exosomes induce the proliferation and migration of normal and chronic wound fibroblasts, and enhance angiogenesis in vitro,” Stem Cells and Development, 2015. View at: Publisher Site | Google Scholar
  260. Y. Zhang, M. Chopp, Y. Meng et al., “Effect of exosomes derived from multipluripotent mesenchymal stromal cells on functional recovery and neurovascular plasticity in rats after traumatic brain injury,” Journal of Neurosurgery, vol. 122, no. 4, pp. 856–867, 2015. View at: Publisher Site | Google Scholar
  261. Y.-G. Zhu, X.-M. Feng, J. Abbott et al., “Human mesenchymal stem cell microvesicles for treatment of Escherichia coli endotoxin-induced acute lung injury in mice,” Stem Cells, vol. 32, no. 1, pp. 116–125, 2014. View at: Publisher Site | Google Scholar
  262. K. Deng, D. L. Lin, B. Hanzlicek et al., “Mesenchymal stem cells and their secretome partially restore nerve and urethral function in a dual muscle and nerve injury stress urinary incontinence model,” The American Journal of Physiology: Renal Physiology, vol. 308, no. 2, pp. F92–F100, 2015. View at: Publisher Site | Google Scholar
  263. M. Ono, N. Kosaka, N. Tominaga et al., “Exosomes from bone marrow mesenchymal stem cells contain a microRNA that promotes dormancy in metastatic breast cancer cells,” Science Signaling, vol. 7, no. 332, 2014. View at: Publisher Site | Google Scholar
  264. J.-K. Lee, S.-R. Park, B.-K. Jung et al., “Exosomes derived from mesenchymal stem cells suppress angiogenesis by down-regulating VEGF expression in breast cancer cells,” PLoS ONE, vol. 8, no. 12, Article ID e84256, 2013. View at: Publisher Site | Google Scholar

Copyright © 2015 J.-F. Stoltz et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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