Anemia

Preoperative Hematocrit Concentration and the Risk of Stroke in Patients Undergoing Isolated Coronary-Artery Bypass Grafting

Tue, 30 Apr 2013 15:29:14 +0000

Background. Identification and management of risk factors for stroke following isolated coronary artery bypass grafting (CABG) could potentially lower the risk of such serious morbidity. Methods. We retrieved data for 30-day stroke incidence and perioperative variables for patients undergoing isolated CABG and used multivariate logistic regression to assess the adjusted effect of preoperative hematocrit concentration on stroke incidence. Results. In 2,313 patients (mean age 65.9 years, 73.6% men), 43 (1.9%, 95% CI: 1.4–2.5) developed stroke within 30 days following CABG (74.4% within 6 days). After adjustment for a priori defined potential confounders, each 1% drop in preoperative hematocrit concentration was associated with 1.07 (95% CI: 1.01–1.13) increased odds for stroke (men, OR: 1.08, 95% CI: 1.01–1.16; women, OR: 1.02, 95% CI: 0.91–1.16). The predicted probability of stroke for descending preoperative hematocrit concentration exceeded 2% for values <37% (<37% for men (adjusted OR: 2.39, 95% CI: 1.08–5.26) and <38% for women (adjusted OR: 2.52, 95% CI: 0.53–11.98), with a steeper probability increase noted in men). The association between lower preoperative hematocrit concentration and stroke was evident irrespective of intraoperative transfusion use. Conclusion. Screening and management of patients with low preoperative hematocrit concentration may alter postoperative stroke risk in patients undergoing isolated CABG.

The Validation of a New Visual Anaemia Evaluation Tool HemoHue HH1 in Patients with End-Stage Renal Disease

Robert M. Kalicki, Stefan Farese, and Dominik E. Uehlinger — Mon, 08 Apr 2013 18:48:51 +0000

In chronic haemodialysis patients, anaemia is a frequent finding associated with high therapeutic costs and further expenses resulting from serial laboratory measurements. HemoHue HH1, HemoHue Ltd, is a novel tool consisting of a visual scale for the noninvasive assessment of anaemia by matching the coloration of the conjunctiva with a calibrated hue scale. The aim of the study was to investigate the usefulness of HemoHue in estimating individual haemoglobin concentrations and binary treatment outcomes in haemodialysis patients. A prospective blinded study with 80 hemodialysis patients comparing the visual haemoglobin assessment with the standard laboratory measurement was performed. Each patient’s haemoglobin concentration was estimated by seven different medical and nonmedical observers with variable degrees of clinical experience on two different occasions. The estimated population mean was close to the measured one (11.06 ± 1.67 versus 11.32 ± 1.23 g/dL, ). A learning effect could be detected. Relative errors in individual estimates reached, however, up to 50%. Insufficient performance in predicting binary outcomes (ROC AUC: 0.72 to 0.78) and poor interrater reliability (Kappa < 0.6) further characterised this method.

The Impact of an Algorithm-Guided Management of Preoperative Anemia in Perioperative Hemoglobin Level and Transfusion of Major Orthopedic Surgery Patients

Wed, 27 Mar 2013 16:16:50 +0000

The aim of this study was to evaluate a laboratory-guided therapeutic algorithm of preoperative anemia. 335 patients with elective hip or knee arthroplasty were included in this retrospective before-after study. Group I () underwent conventional preoperative procedures before algorithm implementation. Group II () underwent algorithm-guided preoperative anemia management. A hemoglobin-level of 13 g/dL was the therapeutic cut-off for men and women. Reticulocyte hemoglobin content (CHr) and soluble transferrin receptor (sTfR)/log ferritin ratio were used in the form of the Thomas plot. Iron deficiency (ID) was substituted with 1000 mg iron intravenous (i.v.) and 10000 international units (I.U.) of erythropoiesis-stimulating agent (ESA) subcutaneous (s.c.) or i.v., anemia of chronic disease (ACD) (without functional ID) with 40000 I.U. ESA s.c. or i.v and additionally 200 mg iron i.v. Substituted anemic patients in Group II () showed a distinctly higher preoperative (Hb-median 13 versus 11.95 g/dL) () and postoperative (Hb-median 9.75 versus 9.0 g/dL) () Hb level compared with untreated anemic patients in Group I (). In Group II red blood cell (RBC) units (35 units/234 patients) were reduced by 44% compared with Group I (27 units/101 patients). Algorithm-guided preoperative anemia management raises perioperative Hb-level and reduces blood use.

Prevalence and Risk Factors of Anemia among Children 6–59 Months Old in Haiti

Sun, 10 Mar 2013 10:37:51 +0000

Anemia has serious consequences on child growth, development, and survival. This study was conducted in Fond des Blancs and Villa, Haiti, to assess the prevalence of childhood anemia and its risk factors in order to inform program design. Children 6–59 months old () were selected using a cross-sectional multistage sampling methodology. Hemoglobin was measured using the HemoCue technique. Descriptive and multivariate analyses were performed to determine prevalence and factors associated with anemia. The prevalence of childhood anemia was 38.8% (23.9% mild, 14.7% moderate, and 0.2% severe). Mean hemoglobin was g/dL. Variables associated with child anemia were age less than 24 months (; ), stunting (; ), and mother’s low hemoglobin level (; ). Anemia among young children in Fond des Blancs and Villa is a public health problem. Predictors of child anemia in this region include child’s age, stunting, and mother’s anemia. Interventions and strategies aimed at addressing effectively anemia in this population must therefore target mothers and children under two years of age.

Traditional Herbal Management of Sickle Cell Anemia: Lessons from Nigeria

Sunday J. Ameh, Florence D. Tarfa, and Benjamin U. Ebeshi — Thu, 08 Nov 2012 10:16:54 +0000

Background. Patients in West Africa where sickle cell anemia (SCA) is endemic have for ages been treated with natural products, especially herbs, as, is still the case in rural communities. Objective. In this paper we look closely at some of these herbs to see if there are any lessons to be learnt or clues to be found for optimizing the treatments based on them, as had been done in the case of NIPRISAN, which was developed from herbs in Nigeria based on Yoruba Medicine. Methods. Select publications on SCA, its molecular biology and pathology, and actual and experimental cases of herbal treatment were perused in search of molecular clues that can be linked to chemical constituents of the herbs involved. Results. The study revealed that during the last 2-3 decades, much progress was made in several aspects of SCA pharmacology, especially the approval of hydroxyurea. As for SCA herbalism, this paper revealed that antisickling herbs abound in West Africa and that the most promising may yet be found. Three new antisickling herbs (Entandrophragma utile, Chenopodium ambrosioides, and Petiveria alliacea) were reported in May 2011. At NIPRD, where NIPRISAN was developed, three other recipes are currently awaiting development. Conclusion. The study raised the hope that the search in the Tropics for more effective herbal recipes for managing sickle cell anaemia will be more fruitful with time and effort.

Relationship between Plasma Ferritin Level and Siderocyte Number in Splenectomized β-Thalassemia/HbE Patients

Wed, 24 Oct 2012 19:09:06 +0000

Introduction. In iron overload status, excess iron deposits in reticuloendothelial cells and tissues and can be detected using Prussian blue staining. The aim of this paper was to investigate the relationship between siderocyte numbers and plasma ferritin levels (a practically standard marker of iron overload) in the blood of the splenectomized and nonsplenectomized -thalassemia/HbE patients, who are at risk of iron overload. Methods. EDTA blood samples from 64 patients with 35 splenectomized and 29 nonsplenectomized -thalassemia/HbE patients, who received regular blood transfusions, and 20 normal individuals were investigated for siderocyte numbers, plasma ferritin levels, and complete blood counts. Results. The average percent siderocytes in splenectomized and nonsplenectomized -thalassemia/HbE patients were 11.5% and 0.08%, respectively, and plasma ferritin levels of 2,332 g/L and 1,279 g/L, respectively. Percent siderocytes showed a good correlation with plasma ferritin levels only in splenectomized patients (, ). A receiver operating curve analysis from splenectomized patients’ data indicated that siderocytes at 3% cut-off are the best predictor for plasma ferritin level ≥1,000 μg/L with 92.9% sensitivity and 42.9% specificity. Conclusion. Circulating siderocyte numbers can be used as a screening test for the assessment of the iron overload in splenectomized -thalassemia/HbE patients in the place where serum ferritin is not available.

Management of Anemia of Inflammation in the Elderly

Antonio Macciò and Clelia Madeddu — Wed, 03 Oct 2012 14:16:25 +0000

Anemia of any degree is recognized as a significant independent contributor to morbidity, mortality, and frailty in elderly patients. Among the broad types of anemia in the elderly a peculiar role seems to be played by the anemia associated with chronic inflammation, which remains the most complex form of anemia to treat. The origin of this nonspecific inflammation in the elderly has not yet been clarified. It seems more plausible that the oxidative stress that accompanies ageing is the real cause of chronic inflammation of the elderly and that the same oxidative stress is actually a major cause of this anemia. The erythropoietic agents have the potential to play a therapeutic role in this patient population. Despite some promising results, rHuEPO does not have a specific indication for the treatment of anemia in the elderly. Moreover, concerns about their side effects have spurred the search for alternatives. Considering the etiopathogenetic mechanisms of anemia of inflammation in the elderly population, an integrated nutritional/dietetic approach with nutraceuticals that can manipulate oxidative stress and related inflammation may prevent the onset of this anemia and its negative impact on patients’ performance and quality of life.

A Molecular, Genetic, and Diagnostic Spotlight on Fanconi Anemia

Laura E. Hays, Stefan Meyer, and Henri J. van de Vrugt — Tue, 02 Oct 2012 08:45:48 +0000

β-Thalassemia: New Therapeutic Modalities, Genetics, Complications, and Quality of Life

Mehran Karimi, Sezaneh Haghpanah, Ali T. Taher, and Maria Domenica Cappellini — Tue, 18 Sep 2012 10:42:19 +0000

Safety and Efficacy of Intravenous Ferric Carboxymaltose (750 mg) in the Treatment of Iron Deficiency Anemia: Two Randomized, Controlled Trials

Mon, 10 Sep 2012 14:07:36 +0000

Background. Iron deficiency anemia (IDA) is a common hematological complication with potentially serious clinical consequences that may require intravenous iron therapy. Ferric carboxymaltose (FCM) is a stable, nondextran iron formulation administered intravenously in large single doses to treat IDA. Objective. Two open-label, randomized, placebo-controlled trials evaluated safety of multiple or single 750 mg FCM doses compared to standard medical care (SMC) in IDA patients. Secondary endpoints were improvements in hemoglobin and iron indices. Design and Patients. Adults with hemoglobin ≤12 g/dL, ferritin ≤100 or ≤300 ng/mL with transferrin saturation ≤30% were randomized to receive single (𝑛=366) or weekly (𝑛=343) FCM or SMC (𝑛=360 and 𝑛=366). Results. Significantly greater (𝑃≤0.001) increases in hemoglobin and iron indices occurred in FCM groups versus SMC. In the multidose study, up to two infusions of FCM were needed to reach target iron levels versus 3–5 of intravenous iron comparators. FCM and SMC groups had similar incidences and types of adverse events and serious adverse events. Transient hypophosphatemia not associated with adverse events or clinical sequelae occurred in the FCM groups. Conclusion. Intravenous FCM is safe, well tolerated, and associated with improvements in hemoglobin and iron indices comparable to SMC when administered in single doses of up to 750 mg at a rate of 100 mg/min. Fewer FCM infusions were required to reach target iron levels compared to other intravenous iron preparations.

Reduced PKC 𝛼 Activity Induces Senescent Phenotype in Erythrocytes

Rukmini B. Govekar, Poonam D. Kawle, Suresh H. Advani, and Surekha M. Zingde — Tue, 04 Sep 2012 11:46:18 +0000

The molecular mechanism mediating expression of senescent cell antigen-aggregated or cleaved band 3 and externalized phosphatidylserine (PS) on the surface of aged erythrocytes and their premature expression in certain anemias is not completely elucidated. The erythrocytes with these surface modifications undergo macrophage-mediated phagocytosis. In this study, the role of protein kinase C (PKC) isoforms in the expression of these surface modifications was investigated. Inhibition of PKC 𝛼 by 30 μM rottlerin (R30) and 2.3 nM Gö 6976 caused expression of both the senescent cell marker-externalized PS measured by FACS analysis and aggregated band 3 detected by western blotting. In contrast to this observation, but in keeping with literature, PKC activation by phorbol-12-myristate-13-acetate (PMA) also led to the expression of senescence markers. We explain this antithesis by demonstrating that PMA-treated cells show reduction in the activity of PKC 𝛼, thereby simulating inhibition. The reduction in PKC 𝛼 activity may be attributed to the known downregulation of PMA-activated PKC 𝛼, caused by its membrane translocation and proteolysis. We demonstrate membrane translocation of PKC 𝛼 in PMA-treated cells to substantiate this inference. Thus loss of PKC 𝛼 activity either by inhibition or downregulation can cause surface modifications which can trigger erythrophagocytosis.

Sickle Cell Disease: Genetics, Cellular and Molecular Mechanisms, and Therapies

Betty S. Pace, Solomon F. Ofori-Acquah, and Kenneth R. Peterson — Wed, 22 Aug 2012 11:32:51 +0000

An Epidemiological Study of Anemia and Renal Dysfunction in Patients Admitted to ICUs across the United States

Donald F. Brophy, Spencer E. Harpe, Daniel E. Carl, and Gretchen M. Brophy — Tue, 14 Aug 2012 13:35:08 +0000

The aims of this study were to determine the associations between anemia of critical illness, erythropoietin stimulating agents (ESA), packed red blood cell transfusions and varying degrees of renal dysfunction with mortality, and ICU- and hospital length of stay (LOS). This was a cross-sectional retrospective study of 5,314 ICU patients from USA hospitals. Hospital, patient demographics, and clinical characteristics were collected. Predictors of mortality and hospital and ICU LOS were evaluated using multivariate logistic regression models. The mean ICU admission hemoglobin in this study was 9.4 g/dL. The prevalence of ESA use was 13% and was associated with declining renal function; 26% of the ICU patients in this study received transfusion. ESA utilization was associated with 28% longer hospital LOS (𝑃<0.001). ICU LOS was increased by up to 18% in patients with eGFR rates of <30 and 30–59 mL/min/1.73 m2, respectively (𝑃<0.05) but not in those receiving dialysis. Mortality was significantly associated with renal dysfunction and dialysis with odds ratios of 1.94, 2.66 and 1.40 for the dialysis, and eGFR rates of <30 and 30–59 and mL/min/1.73 m2, respectively (𝑃<0.05). These data provide a snapshot of anemia treatment practices and outcomes in USA ICU patients with varying degrees of renal dysfunction.

Health-Related Quality of Life, Treatment Satisfaction, Adherence and Persistence in β-Thalassemia and Myelodysplastic Syndrome Patients with Iron Overload Receiving Deferasirox: Results from the EPIC Clinical Trial

Sun, 12 Aug 2012 10:32:05 +0000

Treatment of iron overload using deferoxamine (DFO) is associated with significant deficits in patients' health-related quality of life (HRQOL) and low treatment satisfaction. The current article presents patient-reported HRQOL, satisfaction, adherence, and persistence data from β-thalassemia (𝑛=274) and myelodysplastic syndrome (MDS) patients (𝑛=168) patients participating in the Evaluation of Patients' Iron Chelation with Exjade (EPIC) study (NCT00171821); a large-scale 1-year, phase IIIb study investigating the efficacy and safety of the once-daily oral iron chelator, deferasirox. HRQOL and satisfaction, adherence, and persistence to iron chelation therapy (ICT) data were collected at baseline and end of study using the Medical Outcomes Short-Form 36-item Health Survey (SF-36v2) and the Satisfaction with ICT Questionnaire (SICT). Compared to age-matched norms, β-thalassemia and MDS patients reported lower SF-36 domain scores at baseline. Low levels of treatment satisfaction, adherence, and persistence were also observed. HRQOL improved following treatment with deferasirox, particularly among β-thalassemia patients. Furthermore, patients reported high levels of satisfaction with deferasirox at end of study and greater ICT adherence, and persistence. Findings suggest deferasirox improves HRQOL, treatment satisfaction, adherence, and persistence with ICT in β-thalassemia and MDS patients. Improving such outcomes is an important long-term goal for patients with iron overload.

Foetal Haemoglobin, Erythrocytes Containing Foetal Haemoglobin, and Hematological Features in Congolese Patients with Sickle Cell Anaemia

Thu, 05 Jul 2012 13:18:35 +0000

High HbF levels and F cells are correlated with reduced morbidity and mortality in sickle cell disease (SCD). This paper was designed to determine the HbF and F cells levels in Congolese sickle cell anemia (SCA) patients in order to determine their impact on the expression of SCD. Population and Method. HbF levels were measured in 89 SCA patients (mean age 11.4 yrs) using a standard HPLC method. F cell quantitation was done in a second group of SCA patients (𝑛=42, mean age 8.9 yrs) and compared with a control group (𝑛=47, mean age 5 yrs). F cells were quantified by a cytofluorometric system (MoAb-HbF—FITC; cut off at 0.5%). Results. The mean value of HbF was 7.2% ± 5.0 with heterogeneous distribution, most patients (76%) having HbF < 8%. Mean values of F-cells in SCA patients and control group were 5.4% ± 7.6 (median: 2.19% ; range 0,0–30,3%) and 0.5% ± 1.6 (median 0.0, range 0–5.18), respectively. SCA patients with F cells >4.5% developed less painful crisis and had higher percentage of reticulocytes. Conclusion. Congolese SCA patients displayed low levels of HbF and F-cells that contribute to the severity of SCD.

Diagnosis of Fanconi Anemia: Mutation Analysis by Multiplex Ligation-Dependent Probe Amplification and PCR-Based Sanger Sequencing

Thu, 21 Jun 2012 16:24:55 +0000

Fanconi anemia (FA) is a rare inherited disease characterized by developmental defects, short stature, bone marrow failure, and a high risk of malignancies. FA is heterogeneous: 15 genetic subtypes have been distinguished so far. A clinical diagnosis of FA needs to be confirmed by testing cells for sensitivity to cross-linking agents in a chromosomal breakage test. As a second step, DNA testing can be employed to elucidate the genetic subtype of the patient and to identify the familial mutations. This knowledge allows preimplantation genetic diagnosis (PGD) and enables prenatal DNA testing in future pregnancies. Although simultaneous testing of all FA genes by next generation sequencing will be possible in the near future, this technique will not be available immediately for all laboratories. In addition, in populations with strong founder mutations, a limited test using Sanger sequencing and MLPA will be a cost-effective alternative. We describe a strategy and optimized conditions for the screening of FANCA, FANCB, FANCC, FANCE, FANCF, and FANCG and present the results obtained in a cohort of 54 patients referred to our diagnostic service since 2008. In addition, the follow up with respect to genetic counseling and carrier screening in the families is discussed.

Induction of Fetal Hemoglobin In Vivo Mediated by a Synthetic γ-Globin Zinc Finger Activator

Fri, 15 Jun 2012 15:32:40 +0000

Sickle cell disease (SCD) and β-thalassemia patients are phenotypically normal if they carry compensatory hereditary persistence of fetal hemoglobin (HPFH) mutations that result in increased levels of fetal hemoglobin (HbF, γ-globin chains) in adulthood. Thus, research has focused on manipulating the reactivation of γ-globin gene expression during adult definitive erythropoiesis as the most promising therapy to treat these hemoglobinopathies. Artificial transcription factors (ATFs) are synthetic proteins designed to bind at a specific DNA sequence and modulate gene expression. The artificial zinc finger gg1-VP64 was designed to target the −117 region of the Aγ-globin gene proximal promoter and activate expression of this gene. Previous studies demonstrated that HbF levels were increased in murine chemical inducer of dimerization (CID)-dependent bone marrow cells carrying a human β-globin locus yeast artificial chromosome (β-YAC) transgene and in CD34+ erythroid progenitor cells from normal donors and β-thalassemia patients. Herein, we report that gg1-VP64 increased γ-globin gene expression in vivo, in peripheral blood samples from gg1-VP64 β-YAC double-transgenic (bigenic) mice. Our results demonstrate that ATFs function in an animal model to increase gene expression. Thus, this class of reagent may be an effective gene therapy for treatment of some inherited diseases.

Sickling Cells, Cyclic Nucleotides, and Protein Kinases: The Pathophysiology of Urogenital Disorders in Sickle Cell Anemia

Mário Angelo Claudino and Kleber Yotsumoto Fertrin — Wed, 13 Jun 2012 15:25:51 +0000

Sickle cell anemia is one of the best studied inherited diseases, and despite being caused by a single point mutation in the HBB gene, multiple pleiotropic effects of the abnormal hemoglobin S production range from vaso-occlusive crisis, stroke, and pulmonary hypertension to osteonecrosis and leg ulcers. Urogenital function is not spared, and although priapism is most frequently remembered, other related clinical manifestations have been described, such as nocturia, enuresis, increased frequence of lower urinary tract infections, urinary incontinence, hypogonadism, and testicular infarction. Studies on sickle cell vaso-occlusion and priapism using both in vitro and in vivo models have shed light on the pathogenesis of some of these events. The authors review what is known about the deleterious effects of sickling on the genitourinary tract and how the role of cyclic nucleotides signaling and protein kinases may help understand the pathophysiology underlying these manifestations and develop novel therapies in the setting of urogenital disorders in sickle cell disease.

Fanconi Anemia Proteins and Their Interacting Partners: A Molecular Puzzle

Tagrid Kaddar and Madeleine Carreau — Tue, 12 Jun 2012 13:50:58 +0000

In recent years, Fanconi anemia (FA) has been the subject of intense investigations, primarily in the DNA repair research field. Many discoveries have led to the notion of a canonical pathway, termed the FA pathway, where all FA proteins function sequentially in different protein complexes to repair DNA cross-link damages. Although a detailed architecture of this DNA cross-link repair pathway is emerging, the question of how a defective DNA cross-link repair process translates into the disease phenotype is unresolved. Other areas of research including oxidative metabolism, cell cycle progression, apoptosis, and transcriptional regulation have been studied in the context of FA, and some of these areas were investigated before the fervent enthusiasm in the DNA repair field. These other molecular mechanisms may also play an important role in the pathogenesis of this disease. In addition, several FA-interacting proteins have been identified with roles in these “other” nonrepair molecular functions. Thus, the goal of this paper is to revisit old ideas and to discuss protein-protein interactions related to other FA-related molecular functions to try to give the reader a wider perspective of the FA molecular puzzle.

Spatiotemporal Dysfunction of the Vascular Permeability Barrier in Transgenic Mice with Sickle Cell Disease

Samit Ghosh, Fang Tan, and Solomon F. Ofori-Acquah — Tue, 12 Jun 2012 13:14:24 +0000

Sickle cell disease (SCD) is characterized by chronic intravascular hemolysis that generates excess cell-free hemoglobin in the blood circulation. Hemoglobin causes multiple endothelial dysfunctions including increased vascular permeability, impaired reactivity to vasoactive agonists, and increased adhesion of leukocytes to the endothelium. While the adhesive and vasomotor defects of SCD associated with cell-free hemoglobin are well defined, the vascular permeability phenotype remains poorly appreciated. We addressed this issue in two widely used and clinically relevant mouse models of SCD. We discovered that the endothelial barrier is normal in most organs in the young but deteriorates with aging particularly in the lung. Indeed, middle-aged sickle mice developed pulmonary edema revealing for the first time similarities in the chronic permeability phenotypes of the lung in mice and humans with SCD. Intravenous administration of lysed red blood cells into the circulation of sickle mice increased vascular permeability significantly in the lung without impacting permeability in other organs. Thus, increased vascular permeability is an endothelial dysfunction of SCD with the barrier in the lung likely the most vulnerable to acute inflammation.

Hematopoietic Stem Cell Function in a Murine Model of Sickle Cell Disease

Mon, 04 Jun 2012 13:44:21 +0000

Previous studies have shown that the sickle environment is highly enriched for reactive oxygen species (ROS). We examined the oxidative effects of sickle cell disease on hematopoietic stem cell function in a sickle mouse model. In vitro colony-forming assays showed a significant decrease in progenitor colony formation derived from sickle compared to control bone marrow (BM). Sickle BM possessed a significant decrease in the KSL (c-kit+, Sca-1+, Lineage−) progenitor population, and cell cycle analysis showed that there were fewer KSL cells in the G0 phase of the cell cycle compared to controls. We found a significant increase in both lipid peroxidation and ROS in sickle-derived KSL cells. In vivo analysis demonstrated that normal bone marrow cells engraft with increased frequency into sickle mice compared to control mice. Hematopoietic progenitor cells derived from sickle mice, however, demonstrated significant impairment in engraftment potential. We observed partial restoration of engraftment by n-acetyl cysteine (NAC) treatment of KSL cells prior to transplantation. Increased intracellular ROS and lipid peroxidation combined with improvement in engraftment following NAC treatment suggests that an altered redox environment in sickle mice affects hematopoietic progenitor and stem cell function.

Integrating Interactive Web-Based Technology to Assess Adherence and Clinical Outcomes in Pediatric Sickle Cell Disease

Mon, 04 Jun 2012 10:12:39 +0000

Research indicates that the quality of the adherence assessment is one of the best predictors for improving clinical outcomes. Newer technologies represent an opportunity for developing high quality standardized assessments to assess clinical outcomes such as patient experience of care but have not been tested systematically in pediatric sickle cell disease (SCD). The goal of the current study was to pilot an interactive web-based tool, the Take-Charge Program, to assess adherence to clinic visits and hydroxyurea (HU), barriers to adherence, solutions to overcome these barriers, and clinical outcomes in 43 patients with SCD age 6–21 years. Results indicate that the web-based tool was successfully integrated into the clinical setting while maintaining high patient satisfaction (>90%). The tool provided data consistent with the medical record, staff report, and/or clinical lab data. Participants reported that forgetting and transportation were major barriers for adherence to both clinic attendance and HU. A greater number of self-reported barriers (𝑃<.01) and older age (𝑃<.05) were associated with poorer clinic attendance and HU adherence. In summary, the tool represents an innovative approach to integrate newer technology to assess adherence and clinical outcomes for pediatric patients with SCD.

A Dutch Fanconi Anemia FANCC Founder Mutation in Canadian Manitoba Mennonites

Mon, 04 Jun 2012 09:08:14 +0000

Fanconi anemia (FA) is a recessive DNA instability disorder associated with developmental abnormalities, bone marrow failure, and a predisposition to cancer. Based on their sensitivity to DNA cross-linking agents, FA cells have been assigned to 15 complementation groups, and the associated genes have been identified. Founder mutations have been found in different FA genes in several populations. The majority of Dutch FA patients belongs to complementation group FA-C. Here, we report 15 patients of Dutch ancestry and a large Canadian Manitoba Mennonite kindred carrying the FANCC c.67delG mutation. Genealogical investigation into the ancestors of the Dutch patients shows that these ancestors lived in four distinct areas in The Netherlands. We also show that the Dutch and Manitoba Mennonite FANCC c.67delG patients share the same haplotype surrounding this mutation, indicating a common founder.

Diagnosis of Fanconi Anemia: Mutation Analysis by Next-Generation Sequencing

Sun, 03 Jun 2012 16:04:46 +0000

Fanconi anemia (FA) is a rare genetic instability syndrome characterized by developmental defects, bone marrow failure, and a high cancer risk. Fifteen genetic subtypes have been distinguished. The majority of patients (≈85%) belong to the subtypes A (≈60%), C (≈15%) or G (≈10%), while a minority (≈15%) is distributed over the remaining 12 subtypes. All subtypes seem to fit within the “classical” FA phenotype, except for D1 and N patients, who have more severe clinical symptoms. Since FA patients need special clinical management, the diagnosis should be firmly established, to exclude conditions with overlapping phenotypes. A valid FA diagnosis requires the detection of pathogenic mutations in a FA gene and/or a positive result from a chromosomal breakage test. Identification of the pathogenic mutations is also important for adequate genetic counselling and to facilitate prenatal or preimplantation genetic diagnosis. Here we describe and validate a comprehensive protocol for the molecular diagnosis of FA, based on massively parallel sequencing. We used this approach to identify BRCA2, FANCD2, FANCI and FANCL mutations in novel unclassified FA patients.

Loss of Ercc1 Results in a Time- and Dose-Dependent Reduction of Proliferating Early Hematopoietic Progenitors

Sun, 03 Jun 2012 14:07:09 +0000

The endonuclease complex Ercc1/Xpf is involved in interstrand crosslink repair and functions downstream of the Fanconi pathway. Loss of Ercc1 causes hematopoietic defects similar to those seen in Fanconi Anemia. Ercc1−/− mice die 3-4 weeks after birth, which prevents long-term follow up of the hematopoietic compartment. We used alternative Ercc1 mouse models to examine the effect of low or absent Ercc1 activity on hematopoiesis. Tie2-Cre-driven deletion of a floxed Ercc1 allele was efficient (>80%) in fetal liver hematopoietic cells. Hematopoietic stem and progenitor cells (HSPCs) with a deleted allele were maintained in mice up to 1 year of age when harboring a wt allele, but were progressively outcompeted when the deleted allele was combined with a knockout allele. Mice with a minimal Ercc1 activity expressed by 1 or 2 hypomorphic Ercc1 alleles have an extended life expectancy, which allows analysis of HSPCs at 10 and 20 weeks of age. The HSPC compartment was affected in all Ercc1-deficient models. Actively proliferating multipotent progenitors were most affected as were myeloid and erythroid clonogenic progenitors. In conclusion, lack of Ercc1 results in a severe competitive disadvantage of HSPCs and is most deleterious in proliferating progenitor cells.

Physiopathology of Bone Modifications in 𝜷-Thalassemia

Wed, 30 May 2012 09:50:19 +0000

β-thalassemia major (βTM) or Cooley anemia is characterized by significantly reduced or absent synthesis of β-globin chains, which induces important pathologic consequences including hemolytic anemia, altered erythropoiesis, and bone marrow overstimulation. The pathogenesis of bone changes in patients with βTM is not yet completely understood. However, an unbalance in bone mineral turnover resulting from increased resorption and suppression of osteoblast activity has been detected in βTM patients. The abnormal regulation of bone metabolism may be related to hormonal and genetic factors, iron overload and iron chelation therapy, nutritional deficits, and decreased levels of physical activity. Here, we review the most recent findings on the physiopathology of bone abnormalities in βTM. Clinical presentation and radiological features of βTM-related bone changes are also discussed.

A DOG’s View of Fanconi Anemia: Insights from C. elegans

Martin Jones and Ann Rose — Wed, 30 May 2012 08:10:03 +0000

C. elegans provides an excellent model system for the study of the Fanconi Anemia (FA), one of the hallmarks of which is sensitivity to interstrand crosslinking agents. Central to our understanding of FA has been the investigation of DOG-1, the functional ortholog of the deadbox helicase FANCJ. Here we review the current understanding of the unique role of DOG-1 in maintaining stability of G-rich DNA in C. elegans and explore the question of why DOG-1 animals are crosslink sensitive. We propose a dynamic model in which noncovalently linked G-rich structures form and un-form in the presence of DOG-1. When DOG-1 is absent but crosslinking agents are present the G-rich structures are readily covalently crosslinked, resulting in increased crosslinks formation and thus giving increased crosslink sensitivity. In this interpretation DOG-1 is neither upstream nor downstream in the FA pathway, but works alongside it to limit the availability of crosslink substrates. This model reconciles the crosslink sensitivity observed in the absence of DOG-1 function with its unique role in maintaining G-Rich DNA and will help to formulate experiments to test this hypothesis.

Evaluation of Hematological Parameters in Partial Exchange and Packed Cell Transfusion in Treatment of Severe Anemia in Pregnancy

Sudha Salhan, Vrijesh Tripathi, Rajvir Singh, and Harsha S. Gaikwad — Mon, 28 May 2012 10:33:53 +0000

Objectives. Anemia is a major public health problem throughout the world which assumes prominence in pregnant mothers. Patients with severe anemia continue to present themselves at term or in labor. This study was conducted to compare the improvements in hematological parameters of patients receiving partial exchange blood transfusion and transfusion of packed cells without exchange. Methods. One hundred and twenty-five severely anemic antenatal mothers were admitted from outpatient service. Partial exchange transfusion was given to sixty-six patients while fifty-nine received transfusion of packed cells with frusemide cover. Results. The two groups were comparable in terms of age, height, weight, religion, diet, education, occupation of self and husband, and income. Hemoglobin level in Group 1 was comparatively less than Group 2 at prelevel (5.2±1.5 versus 6.6±2.3, 𝑃=0.001) and postlevel (7.2±1.5 versus 8.6±1.8, 𝑃=0.001), respectively, but there was no significant difference between the two modes of transfusion (2.09±1.6 versus 2.01±1.5, 𝑃=0.78). Conclusion. The study produced an equally significant improvement in hematological parameters in partial exchange and packed cell transfusion. Platelet counts were significantly less in partial exchange as compared with packed cell transfusion.

Diagnosis of Fanconi Anemia: Chromosomal Breakage Analysis

Anneke B. Oostra, Aggie W. M. Nieuwint, Hans Joenje, and Johan P. de Winter — Thu, 24 May 2012 15:34:58 +0000

Fanconi anemia (FA) is a rare inherited syndrome with diverse clinical symptoms including developmental defects, short stature, bone marrow failure, and a high risk of malignancies. Fifteen genetic subtypes have been distinguished so far. The mode of inheritance for all subtypes is autosomal recessive, except for FA-B, which is X-linked. Cells derived from FA patients are—by definition—hypersensitive to DNA cross-linking agents, such as mitomycin C, diepoxybutane, or cisplatinum, which becomes manifest as excessive growth inhibition, cell cycle arrest, and chromosomal breakage upon cellular exposure to these drugs. Here we provide a detailed laboratory protocol for the accurate assessment of the FA diagnosis as based on mitomycin C-induced chromosomal breakage analysis in whole-blood cultures. The method also enables a quantitative estimate of the degree of mosaicism in the lymphocyte compartment of the patient.

Targeting the Fanconi Anemia Pathway to Identify Tailored Anticancer Therapeutics

Chelsea Jenkins, Jenny Kan, and Maureen E. Hoatlin — Thu, 24 May 2012 15:30:00 +0000

The Fanconi Anemia (FA) pathway consists of proteins involved in repairing DNA damage, including interstrand cross-links (ICLs). The pathway contains an upstream multiprotein core complex that mediates the monoubiquitylation of the FANCD2 and FANCI heterodimer, and a downstream pathway that converges with a larger network of proteins with roles in homologous recombination and other DNA repair pathways. Selective killing of cancer cells with an intact FA pathway but deficient in certain other DNA repair pathways is an emerging approach to tailored cancer therapy. Inhibiting the FA pathway becomes selectively lethal when certain repair genes are defective, such as the checkpoint kinase ATM. Inhibiting the FA pathway in ATM deficient cells can be achieved with small molecule inhibitors, suggesting that new cancer therapeutics could be developed by identifying FA pathway inhibitors to treat cancers that contain defects that are synthetic lethal with FA.