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Analytical Cellular Pathology
Volume 2015 (2015), Article ID 186716, 9 pages
http://dx.doi.org/10.1155/2015/186716
Review Article

Use of miRNAs as Biomarkers in Sepsis

1Department of Forensic Medicine, “Victor Babes” University of Medicine and Pharmacy, 300041 Timisoara, Romania
2Clinic of Anaesthesia and Intensive Care, Emergency County Hospital “Pius Brinzeu”, 300736 Timisoara, Romania
3Faculty of Medicine, “Victor Babes” University of Medicine and Pharmacy, 300041 Timisoara, Romania
4Faculty of Chemistry, Biology, and Geography, West University of Timisoara, 300115 Timisoara, Romania
5Clinic of Anaesthesia and Intensive Care “Casa Austria”, Emergency County Hospital “Pius Brinzeu”, 300736 Timisoara, Romania

Received 29 April 2015; Revised 15 June 2015; Accepted 21 June 2015

Academic Editor: Yung-Ming Jeng

Copyright © 2015 Raluca Dumache 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.

Abstract

Sepsis is one of the most common causes of death in critical patients. Severe generalized inflammation, infections, and severe physiological imbalances significantly decrease the survival rate with more than 50%. Moreover, monitoring, evaluation, and therapy management often become extremely difficult for the clinician in this type of patients. Current methods of diagnosing sepsis vary based especially on the determination of biochemical-humoral markers, such as cytokines, components of the complement, and proinflammatory and anti-inflammatory compounds. Recent studies highlight the use of new biomarkers for sepsis, namely, miRNAs. miRNAs belong to a class of small, noncoding RNAs with an approximate content of 19–23 nucleotides. Following biochemical and physiological imbalances, the expression of miRNAs in blood or other body fluids changes significantly. Moreover, its stability, specificity, and selectivity make miRNAs ideal candidates for sepsis biomarkers. In conclusion, we can affirm that stable species of circulating miRNAs represent potential biomarkers for monitoring the evolution of sepsis.

1. Introduction

Sepsis is one of the most common causes of death in the hospitalized patients in the intensive care unit [1]. It represents a clinical syndrome resulting from the interaction between the infective pathogen and systemic inflammatory response. In recent years, sepsis remains a challenge for the clinician, especially in terms of monitoring the efficacy of treatment [2]. The increased percentage of patients suffering from sepsis imposed developing new protocols consisting in rapid, inexpensive methods with high specificity and selectivity for evaluation and monitoring treatment. At the moment there are a number of biomarkers for sepsis, mainly used in clinical laboratory analysis. The most used biomarkers for sepsis are procalcitonin (PCT) [3], C-reactive protein (CRP), and interleukin 6 (IL-6) [2]. The problem with these biomarkers is given by their low selectivity and specificity. Recent studies call into question the use of new biomarkers for sepsis, such as miRNAs [4]. The properties that these species have in addition to the conventional biomarkers are their higher stability, selectivity, and specificity [5]. In the present work, we want to present and highlight the possibility of using miRNA species as biomarkers for diagnosis, monitoring, and guiding of the therapy in patients with sepsis.

2. Structural and Biochemical Aspects of miRNAs

miRNAs are noncoding RNA generally formed of 19–24 nucleotides [6]. The first miRNA species was discovered since 1993 in Caenorhabditis elegans and it was called lin-4 [7]. miRNAs synthesis occurs in the cell nucleus through the action of RNA polymerase II on miRNA genes. Through transcription, pre-miRNA species are obtained. Through the action of RNase III endonuclease, called Drosha, pre-miRNA is obtained. In order for the transformation to take place, Drosha requires the cofactor DiGeorge Syndrome Critical Region 8 (DGCR8) [810]. After the formation of pre-miRNA in the nucleus, this species is transferred into the cytoplasm through Exportin-5. Once in the cell cytoplasm, pre-miRNA species is cleaved by a second RNase III endonuclease, called Dicer, along with transactivator RNA binding protein (TRBP) to form mature miRNA (double-stranded) and (passenger strand) [11]. Eventually miRNA will be degraded by the Argonaute protein. The next step in biogenesis of miRNAs is introducing the mature species in the RNA induced silencing complex (RISC). The miRNAs are specifically released by cells under certain conditions of stress. The release mechanisms of miRNAs are passive release when cell death occurs (apoptotic bodies) and active release when cellular secretions occur (exosomes, ribonucleoprotein complexes, high density lipoproteins, and microvesicles) [12, 13]. In Figure 1 is presented the biogenesis mechanism of miRNAs.

Figure 1: miRNA biogenesis mechanism. miRNA synthesis begins with RNA polymerase II action on protein coding genes. (a) Through the transformation phenomenon of the miRNAs genes, pri-miRNA is forming. (b) By the action of RNase III endonuclease (Drosha) and of the DiGeorge Syndrome Critical Region 8 (DGCR8) cofactor, the pre-miRNA is forming. (c) Through transporting protein Exportin-5, pre-miRNA is transferred from the nucleus into the cytoplasm. (d) In the cytoplasm pre-miRNA is attacked by second RNase III endonuclease (Dicer) and transactivator RNA binding protein forming mature miRNA (double-stranded) and (passenger strand). In what follows, mature miRNA induced silencing is taken in complex (RISC). RISC complex contains mature miRNA and protein Argonaute 2 (AGO) that confers increased stability of the complex. After this, miRNAs are released from the cell by two mechanisms: active release (microvesicles, exosomes, and high density lipoprotein particles) and passive release (apoptotic bodies).

3. The Use of miRNAs as Biomarkers in Clinical Diagnosis

In order for a macromolecule or a biochemical species to be used as a biomarker, it must meet certain properties. Regardless of the area of use, biomarkers should be accessible by noninvasive, cheap, and fast methods. Another important aspect is given by the specificity for a particular tissue or for a specific pathology/injury. Regarding the specificity, selectivity, and high stability of miRNAs, this makes them ideal biomarkers in various fields such as forensics, clinical diagnostic analysis of medical research [14].

A significant number of miRNAs are found at intracellular level. However, many studies report the existence of a significant number of miRNAs outside the cell, called circulating miRNAs. Extracellular miRNAs have been identified in several biological fluids, such as blood, urine, saliva, peritoneal fluid, amniotic fluid, bronchial lavage, cerebrospinal fluid, and tears [1517].

Basic features of extracellular miRNAs are represented by high stability and specificity. Although their stability in the extracellular environment is high, most often their stability is increased by encapsulation in lipid vesicles or by forming complexes with various proteins in order to protect them against denaturation. Thus, many miRNAs are found in biological fluids as exosomes, microvesicles, or high density lipoprotein particles [18]. The body fluids are the most accessible biological samples, ideal for the analysis of specific biomarkers. Recent studies report the presence of an increased number of miRNAs specific to each type of biological fluid. Table 1 summarizes the specificity for different types of fluids. Therefore, body fluids are the most accessible biological samples ideal for the analysis of impressive number of biomarkers specific. miRNAs can be detected by DNA microarray [19], quantitative reverse transcription PCR [20], or RNA sequencing [21]. A number of studies talk about the possibility of correlating the expression of miRNAs with a series of pathologies. Thus, the question of using miRNAs as biomarkers for a number of physiological imbalances and diseases was raised. At the moment, different types of miRNAs have been correlated with cardiovascular disease, various cancers, pathophysiological dysfunction, poisoning with various substances, diseases of the central nervous system, metabolic disorders, immunological disorders, infections, and posttraumatic disorders [5, 2224].

Table 1: miRNAs expression in body fluids.

In recent years there has been a very intense research regarding cancer diagnosis through miRNAs. Numerous studies have identified a series of specific miRNAs for each type of cancer in part. Mitchell et al. [25] identified six miRNAs that could serve as biomarkers in prostate cancer diagnosis by noninvasive methods: miRNA-100, miRNA-125b, miRNA-141, miRNA-143, miRNA-205, and miRNA-296 [25]. Ho et al. [26] studied specific miRNA biomarkers for pancreatic cancer and identified the expression of miRNA-210 as a potential candidate [26]. Wang et al. [27] in a similar study identified four miRNAs that could serve as biomarkers in the diagnosis of pancreatic cancer: miRNA-21, miRNA-210, miRNA-155, and miRNA-196a [27]. Lin et al. [28] reported a total of five miRNAs whose expression could serve as a biomarker in the diagnosis of liver cancer: miRNA-15b, miRNA-1975, miRNA-199a-3p, miRNA-199b-3p, and miRNA-421 [28]. Also, a number of miRNAs that can serve as diagnostic biomarkers for colorectal cancer have been identified [29]. Since the death rate from colorectal cancer can be reduced by applying the diagnosis and treatment in the initial stage, several groups of researchers have studied the expression of miRNAs in patients with this condition. Wang et al. [30] showed an increased expression of miRNA-21 and let-7g and also a decreased expression of miRNA-31, miRNA-181b, miRNA-92a, and miRNA-203 in patients with colorectal cancer [30]. Yang et al. [31] also identified miRNA-29c in this type of patients [31]. Tsujiura et al. [32] identified in patients with gastric cancer an increased expression of miRNA-17-5p, miRNA-21, miRNA-106a, miRNA-106b, miRNA-17, and let-7a [32]. Also, current studies confirm the existence of significant correlations between the expression of different miRNAs and a number of cancers. According to the literature, for each type of cancer there might be a specific miRNA that could serve in the future as a noninvasive diagnosis tool [33].

miRNAs can serve to diagnose not only cancers but also other pathologies responsible for a high death rate worldwide. For example, cardiovascular dysfunction kills annually a high percentage of people of all ages worldwide. Diagnostic methods are often expensive and invasive and with low specificity. Using the expression of miRNAs to obtain a differential diagnosis in cardiovascular pathologies is the main subject of study for many research groups [34]. Stather et al. [35] have studied the expression of miRNAs in patients with peripheral arterial disease. The study revealed a number of specific miRNAs for this condition: miRNA-15b, miRNA-16, miRNA-20b, miRNA-25, miRNA-26b, miRNA-27b, miRNA-28-5p, miRNA-126, miRNA-195, miRNA-335, and miRNA-363 [35]. Jansen et al. [36] also revealed a number of miRNAs whose expression was altered in patients with stable coronary artery disease: miRNA-126, miRNA-222, miRNA-21, miRNA-20a, miRNA-27a, miRNA-92a, miRNA-130, miRNA-199a, miRNA-17, miRNA-222, miRNA-21, miRNA-20a, miRNA-27a, miRNA-130, miRNA-92a, and miRNA-17. Moreover, they observed that low concentration of miRNA-126 and miRNA-199a may be correlated with a decreased risk of cardiovascular events [36]. Other cardiovascular pathologies, including arterial hypertension, myocardial infarction, and ischemia, will lead directly to the release of specific biomarkers. Leptidis et al. [37] reported and validated the existence of a series of specific miRNAs for the myocardial infarction: miR-24, miR-125b, miR-214, and miR-195 [37].

Regarding the neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease, many miRNAs have been identified that can be used in the diagnosis of these disorders. Wang et al. [38] studied the expression of miRNAs in the patients with Alzheimer’s disease, proving that miRNA-146 is upregulated, unlike in healthy patients [38]. Tan et al. [39] in a similar study observed and reported that miRNA-125b and miRNA-181c are downregulated, while miRNA-9 is upregulated [39]. Zhao et al. [40], in the study regarding the expression of miRNAs in Parkinson’s disease, reported low levels of miRNA-133b in these patients [40]. In a similar study, Alieva et al. [41] reported increased levels of the following miRNAs: miRNA-7, miRNA-9-5p, miRNA-9-3p, miRNA-129, and miRNA-132.

Both for the emergency units and for the intensive care units, critical patient is a challenge. Corroborating the acute and chronic pathologies, survival rate drops dramatically. Multiple trauma is most often fatal for this type of patients [42]. Spinal cord along with traumatic brain injury is one of the most serious injuries, with a high mortality rate [43, 44]. Expression of miRNAs was studied in severe trauma by different research groups. Izumi et al. [45] studied the expression of miRNA in experimental models with spinal cord injury and reported abnormal expression of miRNA-233 12 hours after injury. In the case of traumatic brain injury (TBI), Lei et al. [46] reported an increased expression of miRNA-21 [46]. One of the severe consequences of posttraumatic injury is represented by severe systemic inflammation, often accompanied by systemic generalized infections. A significant percentage of patients with sepsis develop multiple organ failure. In this case the mortality reaches a dramatic level up to 70% [47]. Numerous studies report the existence of a high level of miRNAs in patients with sepsis, leading to the introduction of possible new biomarkers in monitoring sepsis in such patients [19, 48, 49].

4. Circulating miRNAs as Biomarker for Sepsis

Sepsis is a potentially life-threatening complication of an infection. Sepsis occurs when chemicals released into the bloodstream to fight the infection trigger inflammatory responses throughout the body [1, 50]. This inflammation can trigger a cascade of changes that can damage multiple organ systems, causing them to fail. Sepsis is divided into three categories according to the nature, quantity, and the germs virulence: moderate sepsis, severe sepsis, and septic shock [51, 52]. In case of septic shock, the volemic management becomes challenging in most cases due to lack of response to fluid loading, imposing the implementation of pharmacological support for maintaining physiological parameters. The inflammatory is determined mostly by a series of inflammatory mediators. By their synergistic or antagonistic action, both beneficial and adverse effects can occur, which can lead to complete damage of the cell [5355]. The inflammatory cascade is triggered or augmented by the presence of microorganisms and by toxins. Some microorganisms produce exotoxin (staphylococci and streptococci), others endotoxin (E. coli), and others both exotoxin and endotoxin (Pseudomonas) [56]. The endotoxin is the most involved in the septic shock, mostly due to its biochemical structure (macromolecular complex glucose lipid protein included in the bacterial cell wall) [57].

Complement activation (C) usually precedes hemodynamic disturbances in serious infections. One of the main roles of C is to enable leukocytes to adhere to the endothelium and to release large amounts of inflammatory mediators. Moreover, it interferes with the biochemical function of some enzymes, increasing capillary permeability [57, 58].

The most important inflammatory mediators are cytokines. Their synthesis in sepsis is due to the interaction between a fraction of a lipopolysaccharide (LPS) and a protein normally present in the human body, respectively, lipopolysaccharide binding protein (LBP), with the CD14 receptor on the surface of macrophages [50]. Also, sepsis implies activation of the coagulation cascade and synthesis of other mediators such as hormones, histamine, arachidonic acid derivatives, and chemokines [2, 59, 60].

During sepsis, the inflammatory response is mediated by the activation of toll-like receptor (TLR) and also by downregulation of NF-KB pathway within the macrophages and monocytes [61]. Tsujimoto et al. [62] demonstrated that TLR are also involved in the development of the septic shock. Presently, 10 types of TLR were identified. TLR1, TLR2, TLR3, TLR4, TLR5, and TLR6 are stimulated by some proteins and lipids from the microbial walls. On the other hand, due to their localization into the endoplasmic reticulum, endolysosomes, lysosomes, and endosomes, TLR7, TLR8, and TLR9 present the property of recognizing the microbial nucleic acids [63]. TLR-NF-KB inflammatory response is also involved in the process of sepsis. Due to this fact, the use of corticosteroids, antagonists of tumor necrosis factor (TNF), and antagonists of interleukin 1 receptor does not have good results in treating sepsis [61, 62, 64, 65].

A number of analytical diagnostic methods have been developed over time in order to help monitor and evaluate patients with sepsis. The most common used biomarkers in the diagnosis and evaluation of sepsis are as follows: interleukin 1 (IL-1), interleukin 2 (IL-2), interleukin 6 (IL-6), interleukin 12 (IL-12), interleukin 8 (IL-8), interleukin 4 (IL-4), interleukin 10 (IL-10), interleukin 17 (IL-17), interleukin 13 (IL-13), tumor necrosis factor alpha (TNF-alpha), interferon gamma (INF-gamma), transforming growth factor beta (TGF-beta), procalcitonin (PCT), N-terminal C natriuretic peptide (NT-CNP), C-reactive proteins (CRP), granulocytes and monocytes colony stimulating factor (GM-CSF), leukotrienes, prostaglandins and thromboxane, or components of the complement (C3a and C5a) [2, 3, 66].

For a faster and cheaper diagnosis, in the recent years the researchers have tried new methods of analysis, with the most intensively studied being circulating miRNAs. Recent studies have revealed the presence of a relatively high number of miRNAs whose expression can be correlated with sepsis [67]. Puskarich et al. [68] studied the expression of miRNA-146a, miRNA-223, and miRNA-150. They reported a correlation between the expression of these three miRNAs and sepsis. Moreover, their study shows a direct correlation between the expression of miRNA-150 and a high mortality rate [68]. Vasilescu et al. [69] have studied the expression of miRNAs in patients with sepsis. They report a decrease in the expression of miRNA-150 and miRNA-342-5p in patients with sepsis as opposed to the healthy patients. Moreover, the expression of miRNA-486 and miRNA-182 was much higher in patients with sepsis versus healthy patients, according to the study conducted by Vasilescu and collaborators [69]. Roderburg et al. [14] in a similar study reported an increased expression of miRNA-150 in patients with sepsis. Wang et al. [70] have also studied miRNAs expression in critical patients with sepsis. The study concluded that the expression of miRNA-223 and miRNA-146a is lower in the group of patients with sepsis. In a similar study, Wang et al. [71] confirm these results by highlighting an increased expression of miRNA-146a in healthy patients.

However, there are studies suggesting that miRNA-223 cannot be used as a biomarker for sepsis. Benz et al. [72] in a similar study demonstrate that there is no difference in miRNA-233 levels in patients with sepsis and healthy patients [72]. Another group of miRNAs that can be used as biomarkers for sepsis belongs to the family of miRNA-4772. Ma et al. [73] studied miRNAs from miRNA-4772 family, emphasizing that three of them are relevant to the diagnosing of sepsis. Thus, in the study, they report an increased expression of miRNA-4772-5p-iso, miRNA-4772-5p, and miRNA-4772-3p in patients with sepsis [73].

Huang et al. [74] identified ten miRNAs that can serve as biomarker for sepsis: let-7b, miRNA-15b, miRNA-16, miRNA-210, miRNA-324-3p, miRNA-484, miRNA-486-5p, miRNA-340, and miRNA-324-3p [74]. Wang et al. [54], in a study on the expression of miRNAs conducted on 232 patients, demonstrated that the expression of miRNA-122 is significantly altered compared to healthy patients [54]. In Table 2 are summarized the expressions of miRNAs which may have significant importance in the diagnosis of sepsis.

Table 2: miRNAs expression in sepsis.

A promising method is the use of specific miRNAs to detect microbiological species instead of blood cultures. This can be possible by detecting changes in the expression of miRNAs made by microorganisms. The specificity and selectivity of the method can be increased by detecting the changes in the expression of miRNAs in various bacterial infections [75].

Recent studies report an altered expression of miRNA-146 and miRNA-155 in case of Helicobacter pylori infection [76], Listeria monocytogenes [77], Mycobacterium tuberculosis [78], and Salmonella enterica [79].

In case of Staphylococcus aureus, four specific miRNAs were identified: bta-miRNA-2229, miRNA-499, miRNA-23a, and miRNA99b [80]. Zheng studied the expression of miRNAs in case of Brucella melitensis, identifying the presence of miRNA-92a, miRNA-93, miRNA-181b, and miRNA-1981 [81].

Infections generated by Pseudomonas aeruginosa also modify the expression of miRNAs, especially miRNA-302b [82] and miRNA-233 [83].

How et al. studied the expression of miRNAs in patients with Gram-negative bacilli induced urosepsis. They reported a decreased expression of miRNA-150 () and let-7a () compared with healthy patients [84]. Finally, we can say that the use of miRNAs as diagnostic biomarkers may represent a new perspective in the differential diagnosis between Gram-positive and Gram-negative bacteria.

5. Conclusions

Circulating miRNAs become more widely studied and more used as a biomarker for the diagnosis of a broad spectrum of physiological, metabolic, and biochemical dysfunctions. Using miRNAs as circulating biomarker for sepsis is still in its infancy and additional studies are required to increase the specificity and selectivity of this method. However, at the moment, a high number miRNAs have been validated as specific for sepsis. Strengthening a broader range of specific miRNAs for sepsis is required. In conclusion, we can affirm that it is necessary to improve detection and validation methods of specific miRNAs for sepsis.

Conflict of Interests

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

Acknowledgment

The authors wish to thank the Emergency County Hospital “Pius Branzeu,” Timisoara, for their support in conceiving this work.

References

  1. R. Sonneville, F. Verdonk, C. Rauturier et al., “Understanding brain dysfunction in sepsis,” Annals of Intensive Care, vol. 3, no. 1, article 15, pp. 1–11, 2013. View at Publisher · View at Google Scholar · View at Scopus
  2. S. D. Trancă, C. L. Petrişor, and N. Hagă, “Biomarkers in polytrauma induced systemic inflammatory response syndrome and sepsis—a narrative review,” Romanian Journal of Anaesthesia and Intensive Care, vol. 21, no. 2, pp. 118–122, 2014. View at Google Scholar
  3. M. Sinha, S. Mantri, S. Desai, and A. Kulkarni, “Procalcitonin as an adjunctive biomarker in sepsis,” Indian Journal of Anaesthesia, vol. 55, no. 3, pp. 266–270, 2011. View at Publisher · View at Google Scholar
  4. Z. Wang, H. Luo, X. Pan, M. Liao, and Y. Hou, “A model for data analysis of microRNA expression in forensic body fluid identification,” Forensic Science International: Genetics, vol. 6, no. 3, pp. 419–423, 2012. View at Publisher · View at Google Scholar · View at Scopus
  5. A. Perfetti, S. Greco, E. Bugiardini et al., “Plasma microRNAs as biomarkers for myotonic dystrophy type 1,” Neuromuscular Disorders, vol. 24, no. 6, pp. 509–515, 2014. View at Publisher · View at Google Scholar · View at Scopus
  6. K. Abdelmohsen, S. Srikantan, M.-J. Kang, and M. Gorospe, “Regulation of senescence by microRNA biogenesis factors,” Ageing Research Reviews, vol. 11, no. 4, pp. 491–500, 2012. View at Publisher · View at Google Scholar · View at Scopus
  7. L. Meng, L. Chen, Z. Li, Z.-X. Wu, and G. Shan, “Roles of MicroRNAs in the Caenorhabditis elegans nervous system,” Journal of Genetics and Genomics, vol. 40, no. 9, pp. 445–452, 2013. View at Publisher · View at Google Scholar · View at Scopus
  8. J. Starega-Roslan, J. Krol, E. Koscianska et al., “Structural basis of microRNA length variety,” Nucleic Acids Research, vol. 39, no. 1, pp. 257–268, 2011. View at Publisher · View at Google Scholar · View at Scopus
  9. X. Sun, B. Icli, A. K. Wara et al., “MicroRNA-181b regulates NF-κB—mediated vascular inflammation,” Journal of Clinical Investigation, vol. 122, no. 6, pp. 1–18, 2012. View at Publisher · View at Google Scholar · View at Scopus
  10. F. Borel, P. Konstantinova, and P. L. M. Jansen, “Diagnostic and therapeutic potential of miRNA signatures in patients with hepatocellular carcinoma,” Journal of Hepatology, vol. 56, no. 6, pp. 1371–1383, 2012. View at Publisher · View at Google Scholar · View at Scopus
  11. Y. Huang, X. Lü, Y. Qu, Y. Yang, and S. Wu, “MicroRNA sequencing and molecular mechanisms analysis of the effects of gold nanoparticles on human dermal fibroblasts,” Biomaterials, vol. 37, pp. 13–24, 2015. View at Publisher · View at Google Scholar · View at Scopus
  12. K. Jones, J. P. Nourse, C. Keane, A. Bhatnagar, and M. K. Gandhi, “Plasma microRNA are disease response biomarkers in classical hodgkin lymphoma,” Clinical Cancer Research, vol. 20, no. 1, pp. 253–264, 2014. View at Publisher · View at Google Scholar · View at Scopus
  13. D. Lenkala, E. R. Gamazon, B. LaCroix, H. K. Im, and R. S. Huang, “MicroRNA biogenesis and cellular proliferation,” Translational Research, 2015. View at Publisher · View at Google Scholar
  14. C. Roderburg, M. Luedde, D. Vargas Cardenas et al., “Circulating microRNA-150 serum levels predict survival in patients with critical illness and sepsis,” PLoS ONE, vol. 8, no. 1, Article ID e54612, 2013. View at Publisher · View at Google Scholar · View at Scopus
  15. G. Williams, M. L. Uchimoto, N. Coult, D. World, and E. Beasley, “Body fluid mixtures: resolution using forensic microRNA analysis,” Forensic Science International: Genetics Supplement Series, vol. 4, no. 1, pp. e292–e293, 2013. View at Publisher · View at Google Scholar · View at Scopus
  16. A. Etheridge, I. Lee, L. Hood, D. Galas, and K. Wang, “Extracellular microRNA: a new source of biomarkers,” Mutation Research, vol. 717, no. 1-2, pp. 85–90, 2011. View at Publisher · View at Google Scholar · View at Scopus
  17. J. F. Barger and P. S. Nana-Sinkam, “MicroRNA as tools and therapeutics in lung cancer,” Respiratory Medicine, vol. 109, no. 7, pp. 803–812, 2015. View at Publisher · View at Google Scholar
  18. G. Rabinowits, C. Gerçel-Taylor, J. M. Day, D. D. Taylor, and G. H. Kloecker, “Exosomal microRNA: a diagnostic marker for lung cancer,” Clinical Lung Cancer, vol. 10, no. 1, pp. 42–46, 2009. View at Publisher · View at Google Scholar · View at Scopus
  19. Z. Wang, Z. Ruan, Y. Mao et al., “miR-27a is up regulated and promotes inflammatory response in sepsis,” Cellular Immunology, vol. 290, no. 2, pp. 190–195, 2014. View at Publisher · View at Google Scholar · View at Scopus
  20. I. Summerer, M. Niyazi, K. Unger et al., “Changes in circulating microRNAs after radiochemotherapy in head and neck cancer patients,” Radiation Oncology, vol. 8, no. 1, article 296, 2013. View at Publisher · View at Google Scholar · View at Scopus
  21. P. Rajan, I. M. Sudbery, M. E. M. Villasevil et al., “Next-generation sequencing of advanced prostate cancer treated with androgen-deprivation therapy,” European Urology, vol. 66, no. 1, pp. 32–39, 2014. View at Publisher · View at Google Scholar · View at Scopus
  22. L. Wang, J. Yu, J. Xu, C. Zheng, X. Li, and J. Du, “The analysis of microRNA-34 family expression in human cancer studies comparing cancer tissues with corresponding pericarcinous tissues,” Gene, vol. 554, no. 1, pp. 1–8, 2015. View at Publisher · View at Google Scholar · View at Scopus
  23. C. Mistrellides, K. Lunnon, M. Sattlecker et al., “MicroRNA biomarkers in Alzheimer's disease,” Alzheimer's & Dementia, vol. 9, no. 4, supplement, p. P224, 2013. View at Publisher · View at Google Scholar
  24. M. M. Harraz, T. M. Dawson, and V. L. Dawson, “MicroRNAs in Parkinson's disease,” Journal of Chemical Neuroanatomy, vol. 42, no. 2, pp. 127–130, 2011. View at Publisher · View at Google Scholar · View at Scopus
  25. P. S. Mitchell, R. K. Parkin, E. M. Kroh et al., “Circulating microRNAs as stable blood-based markers for cancer detection,” Proceedings of the National Academy of Sciences of the United States of America, vol. 105, no. 30, pp. 10513–10518, 2008. View at Publisher · View at Google Scholar · View at Scopus
  26. A. S. Ho, X. Huang, H. Cao et al., “Circulating miR-210 as a novel hypoxia marker in pancreatic cancer,” Translational Oncology, vol. 3, no. 2, pp. 109–113, 2010. View at Publisher · View at Google Scholar · View at Scopus
  27. J. Wang, J. Chen, P. Chang et al., “MicroRNAs in plasma of pancreatic ductal adenocarcinoma patients as novel blood-based biomarkers of disease,” Cancer Prevention Research, vol. 2, no. 9, pp. 807–813, 2009. View at Publisher · View at Google Scholar · View at Scopus
  28. L. Lin, Y. Lin, Y. Jin, and C. Zheng, “Microarray analysis of microRNA expression in liver cancer tissues and normal control,” Gene, vol. 523, no. 2, pp. 158–160, 2013. View at Publisher · View at Google Scholar · View at Scopus
  29. P. J. Mishra, “MicroRNAs as promising biomarkers in cancer diagnostics,” Biomarker Research, vol. 2, article 19, 4 pages, 2014. View at Publisher · View at Google Scholar
  30. Q. Wang, Z. Huang, S. Ni et al., “Plasma miR-601 and miR-760 are novel biomarkers for the early detection of colorectal cancer,” PLoS ONE, vol. 7, no. 9, Article ID e44398, 2012. View at Publisher · View at Google Scholar · View at Scopus
  31. I.-P. Yang, H.-L. Tsai, C.-W. Huang et al., “The functional significance of microRNA-29c in patients with colorectal cancer: a potential circulating biomarker for predicting early relapse,” PLoS ONE, vol. 8, no. 6, Article ID e66842, 2013. View at Publisher · View at Google Scholar · View at Scopus
  32. M. Tsujiura, D. Ichikawa, S. Komatsu et al., “Circulating microRNAs in plasma of patients with gastric cancers,” British Journal of Cancer, vol. 102, no. 7, pp. 1174–1179, 2010. View at Publisher · View at Google Scholar · View at Scopus
  33. Y. Toiyama, Y. Okugawa, and A. Goel, “DNA methylation and microRNA biomarkers for noninvasive detection of gastric and colorectal cancer,” Biochemical and Biophysical Research Communications, vol. 455, no. 1-2, pp. 43–57, 2014. View at Publisher · View at Google Scholar · View at Scopus
  34. G. H. Kim, “MicroRNA regulation of cardiac conduction and arrhythmias,” Translational Research, vol. 161, no. 5, pp. 381–392, 2013. View at Publisher · View at Google Scholar · View at Scopus
  35. P. W. Stather, N. Sylvius, J. B. Wild, E. Choke, R. D. Sayers, and M. J. Bown, “Differential MicroRNA expression profiles in peripheral arterial disease,” Circulation: Cardiovascular Genetics, vol. 6, no. 5, pp. 490–497, 2013. View at Publisher · View at Google Scholar · View at Scopus
  36. F. Jansen, X. Yang, S. Proebsting et al., “MicroRNA expression in circulating microvesicles predicts cardiovascular events in patients with coronary artery disease,” The Journal of the American Heart Association, vol. 3, no. 6, Article ID e001249, 2014. View at Publisher · View at Google Scholar
  37. S. Leptidis, H. el Azzouzi, S. I. Lok et al., “A deep sequencing approach to uncover the miRNOME in the human heart,” PLoS ONE, vol. 8, no. 2, Article ID e57800, pp. 1–9, 2013. View at Publisher · View at Google Scholar · View at Scopus
  38. L.-L. Wang, Y. Huang, G. Wang, and S.-D. Chen, “The potential role of microRNA-146 in Alzheimer's disease: biomarker or therapeutic target?” Medical Hypotheses, vol. 78, no. 3, pp. 398–401, 2012. View at Publisher · View at Google Scholar · View at Scopus
  39. L. Tan, J.-T. Yu, Q.-Y. Liu et al., “Circulating miR-125b as a biomarker of Alzheimer's disease,” Journal of the Neurological Sciences, vol. 336, no. 1-2, pp. 52–56, 2014. View at Publisher · View at Google Scholar · View at Scopus
  40. N. Zhao, L. Jin, G. Fei, Z. Zheng, and C. Zhong, “Serum microRNA-133b is associated with low ceruloplasmin levels in Parkinson's disease,” Parkinsonism and Related Disorders, vol. 20, no. 11, pp. 1177–1180, 2014. View at Publisher · View at Google Scholar · View at Scopus
  41. A. K. Alieva, E. V. Filatova, A. V. Karabanov et al., “MiRNA expression is highly sensitive to a drug therapy in Parkinson's disease,” Parkinsonism and Related Disorders, vol. 21, no. 1, pp. 72–74, 2015. View at Publisher · View at Google Scholar · View at Scopus
  42. J. Hazeldine, P. Hampson, and J. M. Lord, “The impact of trauma on neutrophil function,” Injury, vol. 45, no. 12, pp. 1824–1833, 2014. View at Publisher · View at Google Scholar · View at Scopus
  43. N.-K. Liu, X.-F. Wang, Q.-B. Lu, and X.-M. Xu, “Altered microRNA expression following traumatic spinal cord injury,” Experimental Neurology, vol. 219, no. 2, pp. 424–429, 2009. View at Publisher · View at Google Scholar · View at Scopus
  44. H. A. Shehab and Y. H. Nassar, “Neuromarkers as diagnostic adjuvant to cranial CT in closed traumatic brain injury patients admitted to ICU: a preliminary comparative study,” Egyptian Journal of Anaesthesia, vol. 26, no. 4, pp. 267–272, 2010. View at Publisher · View at Google Scholar · View at Scopus
  45. B. Izumi, T. Nakasa, N. Tanaka et al., “MicroRNA-223 expression in neutrophils in the early phase of secondary damage after spinal cord injury,” Neuroscience Letters, vol. 492, no. 2, pp. 114–118, 2011. View at Publisher · View at Google Scholar · View at Scopus
  46. P. Lei, Y. Li, X. Chen, S. Yang, and J. Zhang, “Microarray based analysis of microRNA expression in rat cerebral cortex after traumatic brain injury,” Brain Research, vol. 1284, pp. 191–201, 2009. View at Publisher · View at Google Scholar · View at Scopus
  47. C. C. Moore, I. H. McKillop, and T. Huynh, “MicroRNA expression following activated protein C treatment during septic shock,” Journal of Surgical Research, vol. 182, no. 1, pp. 116–126, 2013. View at Publisher · View at Google Scholar · View at Scopus
  48. A. M. Piccinini and K. S. Midwood, “Endogenous control of immunity against infection: tenascin-C regulates TLR4-mediated inflammation via microRNA-155,” Cell Reports, vol. 2, no. 4, pp. 914–926, 2012. View at Publisher · View at Google Scholar · View at Scopus
  49. G. Reid, M. B. Kirschner, and N. van Zandwijk, “Circulating microRNAs: association with disease and potential use as biomarkers,” Critical Reviews in Oncology/Hematology, vol. 80, no. 2, pp. 193–208, 2011. View at Publisher · View at Google Scholar · View at Scopus
  50. C. M. Comim, O. J. Cassol-Jr, L. S. Constantino et al., “Alterations in inflammatory mediators, oxidative stress parameters and energetic metabolism in the brain of sepsis survivor rats,” Neurochemical Research, vol. 36, no. 2, pp. 304–311, 2011. View at Publisher · View at Google Scholar · View at Scopus
  51. J. C. Schefold, J. Bierbrauer, and S. Weber-Carstens, “Intensive care unit-acquired weakness (ICUAW) and muscle wasting in critically ill patients with severe sepsis and septic shock,” Journal of Cachexia, Sarcopenia and Muscle, vol. 1, no. 2, pp. 147–157, 2010. View at Publisher · View at Google Scholar · View at Scopus
  52. L.-X. Xie, “New biomarkers for sepsis,” Medical Journal of Chinese People's Liberation Army, vol. 38, no. 1, pp. 6–9, 2013. View at Google Scholar · View at Scopus
  53. C. A. Adams, “Sepsis biomarkers in polytrauma patients,” Critical Care Clinics, vol. 27, no. 2, pp. 345–354, 2011. View at Publisher · View at Google Scholar · View at Scopus
  54. H. Wang, B. Yu, J. Deng, Y. Jin, and L. Xie, “Serum miR-122 correlates with short-term mortality in sepsis patients,” Critical Care, vol. 18, no. 6, pp. 1–4, 2014. View at Publisher · View at Google Scholar
  55. J. Jacobi, “Pathophysiology of sepsis,” American Journal of Health-System Pharmacy, vol. 59, supplement 1, pp. 1435–1444, 2002. View at Google Scholar
  56. S. Jadhav, R. Misra, C. Vyawahare, K. Angadi, N. Gandham, and P. Ghosh, “Role of sepsis screen in the diagnosis of neonatal sepsis,” Medical Journal of Dr. D.Y. Patil University, vol. 6, no. 3, pp. 254–257, 2013. View at Google Scholar
  57. M. Bosmann and P. A. Ward, “The inflammatory response in sepsis,” Trends in Immunology, vol. 34, no. 3, pp. 129–136, 2013. View at Publisher · View at Google Scholar · View at Scopus
  58. M. Huber-Lang, A. Kovtun, and A. Ignatius, “The role of complement in trauma and fracture healing,” Seminars in Immunology, vol. 25, no. 1, pp. 73–78, 2013. View at Publisher · View at Google Scholar · View at Scopus
  59. L. Mica, J. Vomela, M. Keel, and O. Trentz, “The impact of body mass index on the development of systemic inflammatory response syndrome and sepsis in patients with polytrauma,” Injury, vol. 45, no. 1, pp. 253–258, 2014. View at Publisher · View at Google Scholar · View at Scopus
  60. E. Crimi, V. Sica, S. Williams-Ignarro et al., “The role of oxidative stress in adult critical care,” Free Radical Biology and Medicine, vol. 40, no. 3, pp. 398–406, 2006. View at Publisher · View at Google Scholar · View at Scopus
  61. L. J. McGhan and D. E. Jaroszewski, “The role of toll-like receptor-4 in the development of multi-organ failure following traumatic haemorrhagic shock and resuscitation,” Injury, vol. 43, no. 2, pp. 129–136, 2012. View at Publisher · View at Google Scholar · View at Scopus
  62. H. Tsujimoto, S. Ono, P. A. Efron, P. O. Scumpia, L. L. Moldawer, and H. Mochizuki, “Role of toll-like receptors in the development of sepsis,” Shock, vol. 29, no. 3, pp. 315–321, 2008. View at Publisher · View at Google Scholar · View at Scopus
  63. H. Chen, E. Koustova, C. Shults, E. A. Sailhamer, and H. B. Alam, “Differential effect of resuscitation on Toll-like receptors in a model of hemorrhagic shock without a septic challenge,” Resuscitation, vol. 74, no. 3, pp. 526–537, 2007. View at Publisher · View at Google Scholar · View at Scopus
  64. U. N. Das, “Serum adipocyte fatty acid-binding protein in the critically ill,” Critical Care, vol. 17, article 121, 2013. View at Publisher · View at Google Scholar · View at Scopus
  65. F. R. Coelho and J. O. Martins, “Diagnostic methods in sepsis: the need of speed,” Revista da Associacao Medica Brasileira, vol. 58, no. 4, pp. 498–504, 2012. View at Publisher · View at Google Scholar · View at Scopus
  66. E. Ii, “Biomarkers of sepsis, a never-ending story,” Jurnalul Roman de Anestezie Terapie Intensiva, vol. 21, no. 2, pp. 83–85, 2014. View at Google Scholar
  67. F. Tacke, C. Roderburg, F. Benz et al., “Levels of circulating miR-133a are elevated in sepsis and predict mortality in critically ill patients,” Critical Care Medicine, vol. 42, no. 5, pp. 1096–1104, 2014. View at Publisher · View at Google Scholar · View at Scopus
  68. M. A. Puskarich, U. Nandi, N. I. Shapiro, S. Trzeciak, J. A. Kline, and A. E. Jones, “Detection of microRNAs in patients with sepsis,” Journal of Acute Disease, vol. 4, no. 2, pp. 101–106, 2015. View at Publisher · View at Google Scholar
  69. C. Vasilescu, S. Rossi, M. Shimizu et al., “MicroRNA fingerprints identify miR-150 as a plasma prognostic marker in patients with sepsis,” PLoS ONE, vol. 4, no. 10, Article ID e7405, 2009. View at Publisher · View at Google Scholar · View at Scopus
  70. J.-F. Wang, M.-L. Yu, G. Yu et al., “Serum miR-146a and miR-223 as potential new biomarkers for sepsis,” Biochemical and Biophysical Research Communications, vol. 394, no. 1, pp. 184–188, 2010. View at Publisher · View at Google Scholar · View at Scopus
  71. L. Wang, H.-C. Wang, C. Chen et al., “Differential expression of plasma miR-146a in sepsis patients compared with non-sepsis-SIRS patients,” Experimental and Therapeutic Medicine, vol. 5, no. 4, pp. 1101–1104, 2013. View at Publisher · View at Google Scholar · View at Scopus
  72. F. Benz, F. Tacke, M. Luedde et al., “Circulating microRNA-223 serum levels do not predict sepsis or survival in patients with critical illness,” Disease Markers, vol. 2015, Article ID 384208, 10 pages, 2015. View at Publisher · View at Google Scholar
  73. Y. Ma, D. Vilanova, K. Atalar et al., “Genome-wide sequencing of cellular microRNAs identifies a combinatorial expression signature diagnostic of sepsis,” PLoS ONE, vol. 8, no. 10, Article ID e75918, 2013. View at Publisher · View at Google Scholar · View at Scopus
  74. J. Huang, Z. Sun, W. Yan et al., “Identification of MicroRNA as sepsis biomarker based on miRNAs regulatory network analysis,” BioMed Research International, vol. 2014, Article ID 594350, 12 pages, 2014. View at Publisher · View at Google Scholar · View at Scopus
  75. H.-L. Jia, C.-H. He, Z.-Y. Wang et al., “MicroRNA expression profile in exosome discriminates extremely severe infections from mild infections for hand, foot and mouth disease,” BMC Infectious Diseases, vol. 14, no. 1, article 506, 2014. View at Publisher · View at Google Scholar · View at Scopus
  76. F. Petrocca, R. Visone, M. R. Onelli et al., “E2F1-regulated microRNAs impair TGFβ-dependent cell-cycle arrest and apoptosis in gastric cancer,” Cancer Cell, vol. 13, no. 3, pp. 272–286, 2008. View at Publisher · View at Google Scholar · View at Scopus
  77. P. Cossart and A. Lebreton, “A trip in the ‘new microbiology’ with the bacterial pathogen Listeria monocytogenes,” FEBS Letters, vol. 588, no. 15, pp. 2437–2445, 2014. View at Publisher · View at Google Scholar · View at Scopus
  78. L. Furci, E. Schena, P. Miotto, and D. M. Cirillo, “Alteration of human macrophages microRNA expression profile upon infection with Mycobacterium tuberculosis,” International Journal of Mycobacteriology, vol. 2, no. 3, pp. 128–134, 2013. View at Publisher · View at Google Scholar · View at Scopus
  79. M. A. Davis, J. Y. Lim, Y. Soyer et al., “Development and validation of a resistance and virulence gene microarray targeting Escherichia coli and Salmonella enterica,” Journal of Microbiological Methods, vol. 82, no. 1, pp. 36–41, 2010. View at Publisher · View at Google Scholar · View at Scopus
  80. W. Jin, E. M. Ibeagha-Awemu, G. Liang, F. Beaudoin, X. Zhao, and L. L. Guan, “Transcriptome microRNA profiling of bovine mammary epithelial cells challenged with Escherichia coli or Staphylococcus aureus bacteria reveals pathogen directed microRNA expression profiles,” BMC Genomics, vol. 15, no. 1, article 181, 2014. View at Publisher · View at Google Scholar · View at Scopus
  81. K. Zheng, “Infection,” International Journal of Biological Sciences, p. 1013, 2012. View at Google Scholar
  82. X. Zhou, X. Li, Y. Ye et al., “MicroRNA-302b augments host defense to bacteria by regulating inflammatory responses via feedback to TLR/IRAK4 circuits,” Nature Communications, vol. 5, 2014. View at Publisher · View at Google Scholar
  83. L. L. Dai, J. X. Gao, C. G. Zou, Y. C. Ma, and K. Q. Zhang, “mir-233 modulates the unfolded protein response in C. elegans during Pseudomonas aeruginosa infection,” PLoS Pathogens, vol. 11, no. 1, Article ID e1004606, 2015. View at Publisher · View at Google Scholar
  84. C.-K. How, S.-K. Hou, H.-C. Shih et al., “Expression profile of MicroRNAs in gram-negative bacterial sepsis,” Shock, vol. 43, no. 2, pp. 121–127, 2015. View at Publisher · View at Google Scholar · View at Scopus
  85. J. A. Weber, D. H. Baxter, S. Zhang et al., “The microRNA spectrum in 12 body fluids,” Clinical Chemistry, vol. 56, no. 11, pp. 1733–1741, 2010. View at Publisher · View at Google Scholar · View at Scopus
  86. S. S. Silva, C. Lopes, A. L. Teixeira, M. J. C. D. Sousa, and R. Medeiros, “Forensic miRNA: potential biomarker for body fluids?” Forensic Science International: Genetics, vol. 14, pp. 1–10, 2015. View at Publisher · View at Google Scholar · View at Scopus
  87. J. Ward, S. Bala, J. Petrasek, and G. Szabo, “Plasma microRNA profiles distinguish lethal injury in acetaminophen toxicity: a research study,” World Journal of Gastroenterology, vol. 18, no. 22, pp. 2798–2804, 2012. View at Publisher · View at Google Scholar · View at Scopus
  88. E. K. Hanson, H. Lubenow, and J. Ballantyne, “Identification of forensically relevant body fluids using a panel of differentially expressed microRNAs,” Analytical Biochemistry, vol. 387, no. 2, pp. 303–314, 2009. View at Publisher · View at Google Scholar · View at Scopus
  89. D. Zubakov, A. W. M. Boersma, Y. Choi, P. F. van Kuijk, E. A. C. Wiemer, and M. Kayser, “MicroRNA markers for forensic body fluid identification obtained from microarray screening and quantitative RT-PCR confirmation,” International Journal of Legal Medicine, vol. 124, no. 3, pp. 217–226, 2010. View at Publisher · View at Google Scholar · View at Scopus
  90. C. Courts and B. Madea, “Micro-RNA—a potential for forensic science?” Forensic Science International, vol. 203, no. 1–3, pp. 106–111, 2010. View at Publisher · View at Google Scholar · View at Scopus
  91. C. Courts and B. Madea, “Specific micro-RNA signatures for the detection of saliva and blood in forensic body-fluid identification,” Journal of Forensic Sciences, vol. 56, no. 6, pp. 1464–1470, 2011. View at Publisher · View at Google Scholar · View at Scopus
  92. B. Gao, D. Wang, W. Ma et al., “MicroRNA-mRNA regulatory network study and apoptosis analysis on bone marrow endothelial cells induced by liver cirrhosis serum,” Clinics and Research in Hepatology and Gastroenterology, vol. 38, no. 4, pp. 451–461, 2014. View at Publisher · View at Google Scholar · View at Scopus
  93. K. Essandoh and G.-C. Fan, “Role of extracellular and intracellular microRNAs in sepsis,” Biochimica et Biophysica Acta, vol. 1842, no. 11, pp. 2155–2162, 2014. View at Publisher · View at Google Scholar · View at Scopus
  94. C. Haas, E. Hanson, and J. Ballantyne, Encyclopedia of Forensic Sciences, Elsevier, 2013.
  95. M. Louise Hull and V. Nisenblat, “Tissue and circulating microRNA influence reproductive function in endometrial disease,” Reproductive BioMedicine Online, vol. 27, no. 5, pp. 515–529, 2013. View at Publisher · View at Google Scholar · View at Scopus
  96. M. Halimi, H. Parsian, S. M. Asghari et al., “Clinical translation of human microRNA 21 as a potential biomarker for exposure to ionizing radiation,” Translational Research, vol. 163, no. 6, pp. 578–584, 2014. View at Publisher · View at Google Scholar · View at Scopus
  97. M. A. Elovitz, L. Anton, J. Bastek, and A. G. Brown, “Can microRNA profiling in maternal blood identify women at risk for preterm birth,” American Journal of Obstetrics & Gynecology, vol. 212, no. 6, pp. 782.e1–782.e5, 2015. View at Google Scholar
  98. H. Wang, P. Zhang, W. Chen, D. Feng, Y. Jia, and L. Xie, “Serum microRNA signatures identified by Solexa sequencing predict sepsis patients' mortality: a prospective observational study,” PLoS ONE, vol. 7, no. 6, Article ID e38885, pp. 1–9, 2012. View at Publisher · View at Google Scholar · View at Scopus
  99. H. Wang, K. Meng, W. J. Chen, D. Feng, Y. Jia, and L. Xie, “Serum miR-574-5p: a prognostic predictor of sepsis patients,” Shock, vol. 37, no. 3, pp. 263–267, 2012. View at Publisher · View at Google Scholar · View at Scopus