Pathophysiology of sickle cell disease: role of cellular and genetic modifiers

The Multifaceted Roles of BACH1 in Disease: Implications for Biological Functions and Therapeutic Applications

BTB domain and CNC homolog 1 (BACH1) belongs to the family of basic leucine zipper proteins and is expressed in most mammalian tissues. It can regulate its own expression and play a role in transcriptionally activating or inhibiting downstream target genes. It has a crucial role in various biological processes, such as oxidative stress, cell cycle, heme homeostasis, and immune regulation. Recent research highlights BACH1's significant regulatory roles in a series of conditions, including stem cell pluripotency maintenance and differentiation, growth, senescence, and apoptosis. BACH1 is closely associated with cardiovascular diseases and contributes to angiogenesis, atherosclerosis, restenosis, pathological cardiac hypertrophy, myocardial infarction, and ischemia/reperfusion (I/R) injury. BACH1 promotes tumor cell proliferation and metastasis by altering tumor metabolism and the epithelial-mesenchymal transition phenotype. Moreover, BACH1 appears to show an adverse role in diseases such as neurodegenerative diseases, gastrointestinal disorders, leukemia, pulmonary fibrosis, and skin diseases. Inhibiting BACH1 may be beneficial for treating these diseases. This review summarizes the role of BACH1 and its regulatory mechanism in different cell types and diseases, proposing that precise targeted intervention of BACH1 may provide new strategies for human disease prevention and treatment.

Unlocking the link between haptoglobin polymorphism and noninfectious human diseases: insights and implications

Haptoglobin (Hp) is a polymorphic protein that was initially described as a hemoglobin (Hb)-binding protein. The major functions of Hp are to scavenge Hb, prevent iron loss, and prevent heme-based oxidation. Hp regulates angiogenesis, nitric oxide homeostasis, immune responses, and prostaglandin synthesis. Genetic polymorphisms in the Hp gene give rise to different phenotypes, including Hp 1-1, Hp 2-1, and Hp 2-2. Extensive research has been conducted to investigate the association between Hp polymorphisms and several medical conditions including cardiovascular disease, inflammatory bowel disease, cancer, transplantation, and hemoglobinopathies. Generally, the Hp 2-2 phenotype is associated with increased disease risk and poor outcomes. Over the years, the Hp 2 allele has spread under genetic pressures. Individuals with the Hp 2-2 phenotype generally exhibit lower levels of CD163 expression in macrophages. The decreased expression of CD163 may be associated with the poor antioxidant capacity in the serum of subjects carrying the Hp 2-2 phenotype. However, the Hp 1-1 phenotype may confer protection in some cases. The Hp1 allele has strong antioxidant, anti-inflammatory, and immunomodulatory properties. It is important to note that the benefits of the Hp1 allele may vary depending on genetic and environmental factors as well as the specific disease or condition under consideration. Therefore, the Hp1 allele may not necessarily confer advantages in all situations, and its effects may be context-dependent. This review highlights the current understanding of the role of Hp polymorphisms in cardiovascular disease, inflammatory bowel disease, cancer, transplantation, hemoglobinopathies, and polyuria.

Anti-inflammatory cytokines in sickle cell disease

Sickle cell disease (SCD) is a well-studied monogenetic disease with an established chronic inflammatory component. The paradigm shift towards inflammation has made the pathophysiology of SCD even more complex. Studies have shown that an imbalance between the pro-inflammatory and anti-inflammatory cytokines in SCD exists; however, the reports are skewed toward the pro-inflammatory mediators. We enumerate recent in vitro and in vivo studies on anti-inflammatory cytokines in SCD patients, and discuss the biology of anti-inflammatory cytokines including the already reported IL-2, TGF-β, and IL-10 as well as the recently discovered IL-27, IL-35 and IL-37. This review will improve the understanding of the pathophysiology of SCD and aid in the search of new therapeutic options for patients with SCD.

Operational analysis of the national sickle cell screening programme in the Republic of Uganda

Background

Sickle cell anaemia is a common global life-threatening haematological disorder. Most affected births occur in sub-Saharan Africa where children usually go undiagnosed and die early in life. Uganda’s national sickle cell screening programme was developed in response to a 2014 sickle cell surveillance study that documented a high disease prevalence.

Objective

This study describes the temporal and financial aspects of Uganda’s 2014–2019 sickle cell screening programme.

Methods

National sickle cell screening data from Uganda’s Central Public Health Laboratories were used to calculate turn-around times (TATs) from sample collection to delivery, testing, and result reporting for blood samples collected from February 2014 to March 2019. The parameters affecting specific TATs were assessed. The exact programme expenditures were analysed to determine cost per test and per positive sickle cell disease case detected.

Results

A total of 278 651 samples were analysed. The median TAT from sample collection to laboratory receipt was 8 days (interquartile range [IQR]: 6–12), receipt to testing was 3 days (IQR: 1–7), and testing to result reporting was 6 days (IQR: 3–12). Altogether, the sample continuum averaged 16 days (IQR: 11–24). Lower level healthcare facilities were associated with longer sample delivery TATs. Calendar months (January and December) and larger sample volumes impacted testing and result reporting TATs. The cost per test was $4.46 (United States dollars [USD]) and $483.74 USD per positive case detected.

Conclusion

Uganda’s sickle cell screening programme is efficient and cost-effective. Universal newborn screening is the best strategy for detecting sickle cell anaemia in Uganda.

Interleukin-1 receptor inhibition reduces stroke size in a murine model of sickle cell disease

Sickle cell disease (SCD) is associated with chronic hemolytic anemia and a heightened inflammatory state. The causal role of inflammatory pathways in stroke associated with SCD is unclear. Therefore, the hypothesis that deletion of the non-hematopoietic interleukin-1 receptor (IL-1R) pool may be beneficial in SCD was pursued. Since potential deleterious effects of IL-1R signaling in SCD could be mediated via downstream production of interleukin-6 (IL-6), the role of the nonhematopoietic IL-6 pool was also addressed. Bone marrow transplantation (BMT) from SCD to wild-type (WT) recipient mice was used to generate SCD mice (Wt,SCDbmt). In order to generate mice with nonhematopoietic deficiency of IL-1R or IL-6, SCD marrow was transplanted into IL-1R deficient (IL1R-/-,SCDbmt) or IL-6 deficient recipients (IL6-/-, SCDbmt). Blood counts, reticulocytes, soluble E-selectin (sEsel), and IL-6 levels were analyzed 14-15 weeks post-BMT. Ischemic stroke was induced by middle cerebral artery (MCA) photothrombosis at 16 weeks post-BMT. A separate group of Wt,SCDbmt mice was given the IL-1R inhibitor, anakinra, following stroke induction. Seventy-two hours after MCA occlusion, stroke volume was assessed by staining brain sections with 2,3,5-triphenyltetrazolium chloride. Formalin-fixed brain sections were also stained for macrophages with MAC3, for endothelial activation with ICAM-1, and for loss of blood brain barrier integrity with fibrin (ogen) staining. All SCD mice generated by BMT were anemic and the severity of anemia was not different between Wt,SCDbmt, IL1R-/-,SCDbmt, and IL-6-/-,SCDbmt mice. Three days following MCA occlusion, stroke volume was significantly reduced in IL1R-/-,SCDbmt mice compared to Wt,SCDbmt mice and IL6-/-,SCDbmt mice. Plasma levels of sEsel were lower in IL1R-/-,SCDbmt compared to Wt,SCDbmt and IL-6-/-,SCDbmt mice. Post-stroke treatment of Wt,SCDbmt mice with anakinra decreased stroke size, leukocyte infiltration, ICAM-1 expression, and fibrin(ogen) accumulation compared to vehicle-treated mice. Deficiency of non-hematopoietic IL-1R or treatment with an IL-1R antagonist is sufficient to confer protection against the increased stroke size associated with SCD. These effects of IL1R deficiency are associated with reduced endothelial activation, leukocyte infiltration, and blood brain barrier disruption, and are independent of non-hematopoietic IL-6 signaling.

Frequency of beta S globin gene haplotypes among sickle cell patients in Nigeria

Objective

To determine the frequency of beta s globin gene haplotypes in Nigerian patients with sickle cell disease (SCD) and to measure their correlation with clinical and haematological characteristics.

Methods

This study enrolled patients with SCD and collected their peripheral blood for restriction fragment length polymorphism analysis in order to identify five polymorphic sites in the β-globin gene cluster.

Results

A total of 245 homozygous SCD patients (490 alleles) were included in the study. Among the analysed alleles, 426 (86.9%) had the Benin (BEN) haplotype; 19 (3.9%) had the Senegal (SEN) haplotype; 31 (6.3%) had the Cameroon haplotype; five (1.0%) had the Bantu/Central African Republic haplotype; and nine 9 (1.8%) had atypical haplotypes. No significant association was observed between the haplotypes and haematological events, although patients with the BEN/SEN haplotype showed improved red blood cell counts, haemoglobin levels and red blood cell width index. No significant association was observed between the haplotypes and the three clinical manifestations, although patients with the BEN/SEN haplotype showed a four-fold lower frequency of painful episodes.

Conclusion

These findings suggest that the SEN haplotype combined with the BEN haplotype might contribute toward a better haematological profile and milder clinical severity in SCD.

Automated Oxygen Gradient Ektacytometry: A Novel Biomarker in Sickle Cell Anemia

Sickle cell anemia (SCA) is a hereditary hemoglobinopathy with a variable phenotype. There is no single biomarker that adequately predicts disease severity and can be used to monitor treatment response in patients in clinical trials and clinical care. The use of clinical outcomes, such as vaso-occlusive crises (VOC), requires long and expensive studies, sometimes with inconclusive results. To address these limitations, there are several biomarkers under study to improve the ability to predict complications and assess treatment response in both clinical and research settings. Oxygen gradient ektacytometry, also called as oxygenscan, is an assay that measures the effects of deoxygenation and reoxygenation on red blood cell (RBC) deformability and is gaining popularity in SCA research, because it captures the dynamic sickling capacity of a patient’s RBCs as they are subjected to an oxygen gradient under steady shear stress. We describe here the oxygenscan methodology and evaluate the correlation between oxygenscan parameters and more well-known biomarkers of SCA such as fetal hemoglobin (HbF), F-cells, and dense red blood cells (DRBCs). Our data indicate that the oxygenscan curve is affected by all these parameters and the result incorporates the effects of %HbF, %F-cells, RBC hydration, and RBC membrane deformability.

Associations between TGF-β1 Levels and Markers of Hemolysis, Inflammation, and Tissue Remodeling in Pediatric Sickle Cell Patients

Transforming growth factor beta (TGF-β) is a cytokine with important involvement in biological processes related to the pathogenesis of sickle cell disease (SCD), including endothelial and vascular dysfunction, inflammation, and hematopoietic homeostasis. This study is aimed at investigating associations between levels of TGF-β1 and classical laboratory biomarkers and inflammatory mediators, as well as the tissue inhibitor of metalloproteases-1 (TIMP-1) and matrix metalloproteinase-9 (MMP-9), in pediatric patients (n = 123) with SCD in steady state: 84 with sickle cell anemia (HbSS) and 39 with hemoglobin SC disease (HbSC). A healthy control (HC) group of 59 individuals was also included. Hematological and biochemical analyses were carried out using electronic methods. TGF-β1, TIMP-1, and MMP-9 plasma quantifications were performed by ELISA. TGF-β1 plasma levels were higher in HbSS individuals than in HbSC and HC. In individuals with HbSS, TGF-β1 levels were positively correlated with red blood cells, hemoglobin, hematocrit, platelets, and TIMP-1. In addition, HbSS individuals with TGF-β1 levels above the median (≥72.29 ng/mL) also presented increased monocyte counts and decreased albumin levels. In patients with HbSC, TGF-β1 levels were positively correlated with leukocytes, eosinophils, lymphocytes, monocytes, and platelets, as well as levels of TIMP-1, VLDL-C, triglycerides, heme, and AST. Additionally, HbSC individuals with TGF-β1 levels above the median (≥47.80 ng/mL) presented increased leukocyte and platelet counts, as well as increased levels of triglycerides, VLDL-C, MMP-9, and TIMP-1, and decreased HDL-C. Our findings suggest that TGF-β1 may play important roles in vascular remodeling, vasculopathy, angiogenesis, and inflammation in pediatric patients with SCD.

Alpha thalassemia, but not βS-globin haplotypes, influence sickle cell anemia clinical outcome in a large, single-center Brazilian cohort

Alpha thalassemia and beta-globin haplotype are considered classical genetic disease modifiers in sickle cell anemia (SCA) causing clinical heterogeneity. Nevertheless, their functional impact on SCA disease emergence and progression remains elusive. To better understand the role of alpha thalassemia and beta-globin haplotype in SCA, we performed a retrospective study evaluating the clinical manifestations of 614 patients. The univariate analysis showed that the presence of alpha-thalassemia -3.7-kb mutation (αα/-α and -α/-α) decreased the risk of stroke development (p = 0.046), priapism (p = 0.033), and cholelithiasis (p = 0.021). Furthermore, the cumulative incidence of stroke (p = 0.023) and cholelithiasis (p = 0.006) was also significantly lower for patients carrying the alpha thalassemia -3.7-kb mutation. No clinical effects were associated with the beta-globin haplotype analysis, which could be explained by the relatively homogeneous haplotype composition in our cohort. Our results reinforce that alpha thalassemia can provide protective functions against hemolysis-related symptoms in SCA. Although, several genetic modifiers can impact the inflammatory state of SCA patients, the alpha thalassemia mutation remains one of the most recurrent genetic aberration and should therefore always be considered first.

Inflammatory Dendritic Cells Contribute to Regulate the Immune Response in Sickle Cell Disease

Sickle cell disease (SCD), one of the most common hemoglobinopathies worldwide, is characterized by a chronic inflammatory component, with systemic release of inflammatory cytokines, due to hemolysis and vaso-occlusive processes. Patients with SCD demonstrate dysfunctional T and B lymphocyte responses, and they are more susceptible to infection. Although dendritic cells (DCs) are the main component responsible for activating and polarizing lymphocytic function, and are able to produce pro-inflammatory cytokines found in the serum of patients with SCD, minimal studies have thus far been devoted to these cells. In the present study, we identified the subpopulations of circulating DCs in patients with SCD, and found that the bloodstream of the patients showed higher numbers and percentages of DCs than that of healthy individuals. Among all the main DCs subsets, inflammatory DCs (CD14⁺ DCs) were responsible for this rise and correlated with higher reticulocyte count. The patients had more activated monocyte-derived DCs (mo-DCs), which produced MCP-1, IL-6, and IL-8 in culture. We found that a CD14⁺ mo-DC subset present in culture from some of the patients was the more activated subset and was mainly responsible for cytokine production, and this subset was also responsible for IL-17 production in co-culture with T lymphocytes. Finally, we suggest an involvement of heme oxygenase in the upregulation of CD14 in mo-DCs from the patients, indicating a potential mechanism for inducing inflammatory DC differentiation from circulating monocytes in the patients, which correlated with inflammatory cytokine production, T lymphocyte response skewing, and reticulocyte count.

TGFBR3 Polymorphisms (rs1805110 and rs7526590) Are Associated with Laboratory Biomarkers and Clinical Manifestations in Sickle Cell Anemia

Individuals with sickle cell anemia (SCA) present chronic anemia, hemolysis, an exacerbated inflammatory response, and heterogeneous clinical complications, which may be modulated by the transforming growth factor beta (TGF-β) pathway. Thus, we aimed to investigate polymorphisms (rs1805110 and rs7526590) of the transforming growth factor beta receptor III gene (TGFBR3) with regard to laboratory biomarkers and clinical manifestations in individuals with SCA. Hematological, biochemical, immunological, and genetic analyses were carried out, as well as serum endothelin-1 measurements. The minor allele (A) of the TGFBR3 rs1805110 polymorphism was associated with increased hemoglobin, hematocrit, reticulocyte counts, total cholesterol, low-density lipoprotein, uric acid, and endothelin levels, as well as decreased platelet distribution width (PDW) and the occurrence of bone alterations. The minor allele (T) of TGFBR3 rs7526590 was associated with increased red cell distribution width, PDW, alkaline phosphatase, aspartate aminotransferase, total and indirect bilirubin, and lactate dehydrogenase levels, as well as lower ferritin levels and the occurrence of leg ulcers. Our data suggest that the minor allele (A) of TGFBR3 rs1805110 is associated with inflammation and bone alterations, while the minor allele (T) of TGFBR3 rs7526590 is related to hemolysis and the occurrence of leg ulcers.

Hydroxyurea Scavenges Free Radicals and Induces the Expression of Antioxidant Genes in Human Cell Cultures Treated With Hemin

The excessive release of heme during hemolysis contributes to the severity of sickle cell anemia (SCA) by exacerbating hemoglobin S (HbS) autoxidation, inflammation and systemic tissue damage. The present study investigated the effect of hydroxyurea (HU) on free radical neutralization and its stimulation of antioxidant genes in human peripheral blood mononuclear cells (PBMC) and human umbilical vein endothelial cells (HUVEC) in the presence or absence of hemin. HU (100 and 200 μM) significantly reduced the production of intracellular reactive oxygen species (ROS) induced by hemin at 70 μM in HUVEC. HUVECs treated with HU+hemin presented significant increases in nitric oxide (NO) production in culture supernatants. HU alone or in combination with hemin promoted the induction of superoxide dismutase-1 (SOD1) and glutathione disulfide-reductase (GSR) in HUVECs and PBMCs, and glutathione peroxidase (GPX1) in PBMCs. Microarray analysis performed in HUVECs indicated that HU induces increased expression of genes involved in the antioxidant response system: SOD2, GSR, microsomal glutathione S-transferase (MGST1), glutathione S-transferase mu 2 (GSTM2), carbonyl reductase 1 (CBR1) and klotho B (KLB). Significant increases in expression were observed in genes with kinase activity: protein kinase C beta (PRKCB), zeta (PRKCZ) and phosphatidylinositol-4-phosphate 3-kinase catalytic subunit type 2 beta (PIK3C2B). HU also induced a significant increase in expression of the gene p62/sequestosome (p62/SQSTM1) and a significant decrease in the expression of the transcriptional factor BACH1 in HUVECs. Upstream analysis predicted the activation of Jun, miR-155-5p and mir-141-3p. These results suggest that HU directly scavenges free radicals and induces the expression of antioxidant genes via induction of the Nrf2 signaling pathway.

Leucocytosis and Asymptomatic Urinary Tract Infections in Sickle Cell Patients at a Tertiary Hospital in Zambia

Sickle cell anaemia (SCA) is an inherited disease resulting from mutations in the β-globin chain of adult haemoglobin that results in the formation of homozygous sickle haemoglobin. It is associated with several complications including an altered blood picture and damage in multiple organs, including the kidneys. Kidney disease is seen in most patients with SCA and may affect glomerular and/or tubular function, thereby putting these patients at risk of urinary tract infections. However, there is a paucity of data on the prevalence of urinary tract infections (UTIs) among SCA patients in Zambia. This study aimed to determine the prevalence of UTIs and haematological and kidney function profiles among SCA patients at the University Teaching Hospitals, Lusaka, Zambia. This was a cross-sectional study conducted between April and July 2019 involving 78 SCA patients who presented at the UTH. Blood and midstream urine samples were collected from each participant using the standard specimen collection procedures. Full blood counts and kidney function tests were determined using Sysmex XT-4000i haematology analyser and the Pentra C200 by Horiba, respectively. Bacterial profiles of the urine samples were determined using conventional microbiological methods. We found that all the measured patients' haemoglobin (Hb) levels fell below the WHO-recommended reference range with a minimum of 5 g/dl, a maximum of 10.5 g/dl, and a mean of 8 ± 1 g/dl. Fifty percent of the participants had moderate anaemia, while the other 50% had severe anaemia. The minimum WBC count of the participants was 0.02 × 10⁹/L with a maximum of 23.36 × 10⁹/L and a mean of 13.48 ± 3.87 × 10⁹/L. Using the one-way analysis of variance test, we found no significant difference in mean WBC count and Hb concentration across various age-group categories that we defined. Bacteriuria was found in 25% of participants. The most common bacterial isolates were Staphylococcus aureus (32%) and coagulase-negative Staphylococci (32%). Klebsiella pneumoniae was 16%. We found no significant association between bacterial isolates and white blood cell count, age groups, sex, and anaemia severity p = 0.41. None of the participants were diagnosed with kidney disease. There was a high prevalence of asymptomatic UTIs among SCA patients at UTH, which, when coupled with the marked leukocytosis and anaemia, may negatively impact the clinical outcome of the patients. Therefore, we recommend close monitoring of sickle cell patients in Zambia for such conditions to improve patients' outcomes.

Hemoglobin SS Nigerian Woman First Diagnosed at the Age of 52 years with Manifestation Mimicking Tuberculosis of the Spine

Sickle cell anemia (SCA) is an inherited disorder of hemoglobin due to the presence of abnormal hemoglobin in a homozygous state. Manifestation is usually in infancy or early childhood due to gradual decrease in hemoglobin F level as age advances. Diagnosis in middle age is unusual. We present a woman who was diagnosed of SCA for the first time at middle age. The aim was to bring to the knowledge of physicians that patients with SCA can also present late so high index of suspicion is required to make diagnosis. A 52-year-old woman presented to orthopedic clinic with complaints of generalized bone pain and low back pain. There was no history of trauma prior to the onset of the pain. There was no associated fever, weight loss, loss of appetite, nor weakness of the lower limbs. X-ray of the spine done showed wedge collapse of the 12^th thoracic and first lumbar vertebrae with posterior angulation of the thoracolumbar junction giving dorsal kyphosis. Her mode of presentation raised a suspicion of tuberculosis of the spine to rule out multiple myeloma. However, investigations for tuberculosis and multiple myeloma were all negative. This necessitated the investigation for SCA and the diagnosis was confirmed. The diagnosis of SCA is usually made in infancy or early childhood. High index of suspicion is required to make the diagnosis at middle age.

Bioinformatics and Translation Elongation

Codon usage depends on mutation bias, tRNA-mediated selection, and the need for high efficiency and accuracy in translation. One codon in a synonymous codon family is often strongly over-used, especially in highly expressed genes, which often leads to a high dN/dS ratio because dS is very small. Many different codon usage indices have been proposed to measure codon usage and codon adaptation. Sense codon could be misread by release factors and stop codons misread by tRNAs, which also contribute to codon usage in rare cases. This chapter outlines the conceptual framework on codon evolution, illustrates codon-specific and gene-specific codon usage indices, and presents their applications. A new index for codon adaptation that accounts for background mutation bias (Index of Translation Elongation) is presented and contrasted with codon adaptation index (CAI) which does not consider background mutation bias. They are used to re-analyze data from a recent paper claiming that translation elongation efficiency matters little in protein production. The reanalysis disproves the claim.

Perioperative Management of Sickle Cell Disease

Over 30 million people worldwide have sickle cell disease (SCD). Emergent and non-emergent surgical procedures in SCD have been associated with relatively increased risks of peri-operative mortality, vaso-occlusive (painful) crisis, acute chest syndrome, post-operative infections, congestive heart failure, cerebrovascular accident and acute kidney injury. Pre-operative assessment must include a careful review of the patient’s known crisis triggers, baseline hematologic profile, usual transfusion requirements, pre-existing organ dysfunction and opioid use. Use of preoperative blood transfusions should be selective and decisions individualized based on the baseline hemoglobin, surgical procedure and anticipated volume of blood loss. Intra- and post-operative management should focus on minimizing hypoxia, hypothermia, acidosis, and intravascular volume depletion. Pre- and post-operative incentive spirometry use should be encouraged.

Adult Sickle Cell Anaemia Patients in Bone Pain Crisis have Elevated Pro-Inflammatory Cytokines

Background and Objectives

Inflammatory markers that influence bone pain crisis (BPC) and other complications of sickle cell anaemia (SCA) are numerous and play various roles. This study determined the plasma levels of tumour necrosis factor (TNF) - α, interleukin - 8 (IL-8), and endothelin - 1 (ET-1) in adult SCA patients during BPC and in steady state. In addition, the plasma levels of these cytokines were correlated with the severity of BPC of the patients.

Methods and Materials

Sixty adult SCA patients (30 during BPC and 30 during steady state) and 30 haemoglobin A controls were enrolled for this cross-sectional study. The severity of BPC was assessed clinically, and questionnaires were filled. Plasma levels of TNF- α, IL-8 and ET-1 were quantified by ELISA, and haematological parameters were determined using a 5-part auto-analyzer. Plasma levels were correlated with the severity of bone pain crisis. Results were considered statistically significant if p<0.05.

Results

Plasma TNF-α, IL-8, and ET-1 were significantly elevated in the BPC group than in the steady state group and the controls. Plasma TNF-α, IL-8 and ET-1 were markedly higher in the severe BPC groups than the steady state and control groups, There was a positive correlation between TNF-α and ET-1 in the bone pain crisis group.

Conclusion

Elevated levels of plasma TNF-α, IL-8, and ET-1 further establish the chronic inflammatory state in SCA and equally affirm their significant contribution, not only to pathogenesis but also to the severity of pain in SCA.

Electrical impedance microflow cytometry with oxygen control for detection of sickle cells

Polymerization of intracellular sickle hemoglobin induced by low oxygen tension has been recognized as a primary determinant of the pathophysiologic manifestations in sickle cell disease. Existing flow cytometry techniques for detection of sickle cells are typically based on fluorescence markers or cellular morphological analysis. Using microfluidics and electrical impedance spectroscopy, we develop a new, label-free flow cytometry for non-invasive measurement of single cells under controlled oxygen level. We demonstrate the capability of this new technique by determining the electrical impedance differential of normal red blood cells obtained from a healthy donor and sickle cells obtained from three sickle cell patients, under normoxic and hypoxic conditions and at three different electrical frequencies, 156 kHz, 500 kHz and 3 MHz. Under normoxia, normal cells and sickle cells can be separated completely using electrical impedance at 156 kHz and 500 kHz but not at 3 MHz. Sickle cells, intra-patient and inter-patient show significantly different electrical impedance between normoxia and hypoxia at all three frequencies. This study shows a proof of concept that electrical impedance signal can be used as an indicator of the disease state of a red blood cell as well as the cell sickling events in sickle cell disease. Electrical impedance-based microflow cytometry with oxygen control is a new method that can be potentially used for sickle cell disease diagnosis and monitoring.

Iron overload in hematological disorders

While most common symptom of impairment of iron homeostasis is iron deficiency anemia, some hematological disorders are associated with iron overload (IO). These disorders are related mainly to chronic severe hemolytic anemia, where red blood cells (RBC) or their precursors are destroyed prematurely (hemolyzed), leading to anemia that cannot be compensated by increased production of new RBC. In such cases, IO is mainly due to repeated RBC transfusions and/or increased uptake of iron in the gastrointestinal tract. Normally, iron is present in the plasma and in the cells bound to compounds that render it redox inactive. Iron overload leaves a fraction of the iron free (labile iron pool) and redox active, leading to the generation of excess free radicals such as the reactive oxygen species. This condition upsets the cellular redox balance between oxidants and antioxidants, leading to oxidative stress. The free radicals bind to various cellular components, thereby becoming toxic to vital organs. Oxidative stress may also affect blood cells, such as RBC, platelets and neutrophils, exacerbating the anemia, and causing recurrent infections and thrombotic events, respectively. The toxic effect of IO can be decreased by treating the patients with iron chelators that enter cells, bind free iron and remove it from the body through the urine and feces. Iron toxicity may be also ameliorated by treatment with anti-oxidants that scavenge free radicals and/or correct their damage. The use of iron chelators is widely accepted when started in young patients with severe chronic anemia, but is still debatable as a therapeutic modality for older patients suffering from IO due to myelodysplastic syndromes. It should be noted that in addition to preventing iron toxicity, some compounds with iron chelator activity may also benefit other aspects of hematological disorders. These aspects include stimulation of platelet production, inhibition of leukemic cell proliferation and induction of their differentiation. Compounds with such multiple activities may prove beneficial for at least some patients with leukemia and myelodysplastic syndromes.

Influence of serum 25-hydroxyvitamin D on the rate of pain episodes in Nigerian children with sickle cell anaemia

BACKGROUND

In sickle cell disease (SCD), symptoms of vitamin D deficiency (VDD) and chronic pain can overlap.

AIM

To examine the relationship between serum vitamin D levels and the frequency of acute pain episodes.

METHODS

In this cross-sectional study, serum 25-hydroxyvitamin D (25-OHD) was assayed by high-performance liquid chromatography, and its influence on the number of significant pain episodes was examined by bivariate and logistic regression analyses.

RESULTS

The mean (SD) serum 25-OHD level in 123 children with SCD (HbSS) was 105.8 (24.1) nmol/L (range 37.5-155.8). Fourteen patients (11.4%) either had a deficient (1.6%) or insufficient (9.8%) level. None had severe VDD. All the children with sub-optimal vitamin D experienced pain, as did 69.7% of those with normal vitamin D [14 (100%) vs 76 (69.7%), 95% CI 0.7-0.9, p = 0.04]. The mean serum vitamin D level in the 90 patients with at least one pain episode [103.1 (25.2) nmol/L] was significantly lower than the 113.1 (19.3) nmol/L in the 33 without a pain episode (95% CI 1.3-7.8, p = 0.04). The frequency of pain correlated inversely with the serum 25-OHD level. Serum levels of vitamin D (OR 1.2, 95% CI 1.3-1.7, p = 0.04) and fetal haemoglobin concentration (OR 1.6, 95% CI 1.1-1.4, p = 0.02) predicted significant pain episodes.

CONCLUSION

In children with SCD, there is a possible association between depressed serum vitamin D levels and increased frequency of acute pain episodes. Vitamin D supplements should be considered in patients with low levels and frequent episodes of pain.

Laboratory and Genetic Biomarkers Associated with Cerebral Blood Flow Velocity in Hemoglobin SC Disease

Reference values for cerebral blood flow velocity (CBFV) in hemoglobin SC disease (HbSC) have not been established. We aimed to investigate associations between laboratory and genetic biomarkers associated with CBFV in HbSC children. Sixty-eight HbSC children were included; CBFV was analyzed by transcranial Doppler, and the time-averaged maximum mean velocity (TAMMV) was estimated. Hematological, biochemical, immunological, and genetic analyses were performed. TAMMV was negatively correlated with red blood cell count (RBC) count, hemoglobin, hematocrit, and direct bilirubin (DB), yet positively correlated with monocytes and ferritin. We found that children with TAMMV ≥ 128 cm/s had decreased red blood cell distribution width (RDW) and nitric oxide metabolite (NOx) concentration. Children with TAMMV ≥ 143.50 cm/s had decreased hemoglobin and hematocrit, as well as increased ferritin levels. Decreased hemoglobin, hematocrit, RDW, and NOx and increased ferritin were detected in children with TAMMV ≥ 125.75 cm/s. The CAR haplotype was associated with higher TAMMV. In association analyses, RBC, hemoglobin, hematocrit, RDW, monocyte, DB, NOx, and ferritin, as well as the CAR haplotype, were found to be associated with higher TAMMV in HbSC children. Multivariate analysis suggested that high TAMMV was independently associated with hematocrit, RDW, and NOx. Additional studies are warranted to validate the establishment of a cutoff value of 125.75 cm/s associated with elevated TAMMV in HbSC children.

Transcranial Doppler in hemoglobin SC disease

BACKGROUND

Stroke is a severe clinical disorder in sickle cell disease (SCD), and few studies have evaluated transcranial Doppler (TCD) flow velocities in hemoglobin SC disease (HbSC). The guidelines for stroke risk are based on evaluations in sickle cell anemia (SCA) or HbS/β thalassemia.

PROCEDURE

In this study, we compare cerebral blood flow in patients with SCD stratified by genotypes. A total of 1,664 pediatric patients with SCD underwent TCD velocity screening, and the time-averaged maximum mean velocity (TAMM) was determined in the middle cerebral artery (MCA), anterior cerebral artery (ACA), and distal intracranial internal carotid artery (ICA).

RESULTS

Abnormal velocities were not identified in the ACA; therefore, we only use ICA and MCA velocities. TAMM from the left and right in the ICA and MCA was 134.3 ± 32.0 and 134.4 ± 32.6 cm/s in patients with SCA, and 105.2 ± 20.6 and 104.7 ± 20.0 cm/s in the patients with HbSC, respectively. Mean TAMM between right and left ICA/MCA was 134.5 ± 30.5 cm/s in the SCA group, and 104.9 ± 19.3 cm/s in the HbSC group. Notably, our data show that TCD velocities were significantly lower among the patients with HbSC compared to SCA. TAMM was negatively correlated with hemoglobin and hematocrit in both genotypes.

CONCLUSION

These results suggest that a different cut-off value for abnormal TCD velocities could be considered for patients with HbSC. Additional studies are warranted to determine the actual risk of stroke in HbSC genotype associated with this possible TCD risk value.

Relationship between serum 25-hydroxyvitamin D and inflammatory cytokines in paediatric sickle cell disease

BACKGROUND

Alteration in the concentration of inflammatory cytokines may contribute to pathogenesis in sickle cell anaemia (SCA). Vitamin D may suppress pro-inflammatory cytokines and enhance anti-inflammatory cytokines.

OBJECTIVE

To compare steady state levels of pro-and anti-inflammatory cytokines of Nigerian SCA children with age- and sex-matched healthy controls, and determine the relationship with 25-hydroxyvitamin-D (25-OHD). Effects of three months of vitamin D supplementation on cytokines of SCA children with suboptimal 25-OHD were also evaluated.

METHODS

Serum 25-OHD, IL-1β, 2, 6, 8, 11, 12, 13, 17, 18 of 95 SCA children and 75 matched controls were determined using HPLC. The 12 SCA children with suboptimal 25-OHD received 2000IU of vitamin D daily for 3months, and their post supplementation cytokines and 25-OHD levels were compared with the baseline values.

RESULTS

IL-2, 6, 8, 12, 17 and 18 were higher in SCA children than the controls (p≤0.001), but no significant variation in IL-11 and 13 (p=0.131 and 0.057 respectively). Patients with suboptimal serum 25-OHD had higher IL-6, 8 and 18 (p=0.003, 0.010 and 0.002 respectively) and lower levels of IL-11 (p=0.005). Significant positive treatment effects were observed: post-supplementation, serum 25-OHD increased by 23.3ng/mL, p<0.001; proinflammatory cytokines IL-2, 6, 8, 17 and 18 (p<0.001) were reduced and anti-inflammatory cytokine IL-11 was increased, p<0.001.

CONCLUSIONS

Suboptimal 25OHD is associated with enhanced levels of pro-inflammatory markers in children with SCA. Three months of daily vitamin D supplementation reversed the trend. Hence; Vitamin D supplementation may reduce the inflammatory milieu and serve as an anti-inflammatory agent in the management of SCA.

Nasopharyngeal and Oropharyngeal Colonization by Staphylococcus aureus and Streptococcus pneumoniae and Prognostic Markers in Children with Sickle Cell Disease from the Northeast of Brazil

We investigated the nasopharynx and oropharynx microbiota in sickle cell disease (SCD) to identify the microorganisms, antibiotic sensitivity, prevalent serotypes, and association of with laboratorial markers. Oropharynx/nasopharynx secretions were investigated in 143 SCD children aging 6 months to 17 years. Pathogens were isolated using standard procedures, and laboratorial markers were performed by automated methods. Staphylococcus aureus (S. aureus) was isolated from nasopharynx and oropharynx of 64 and of 17 SCD children respectively. Streptococcus pneumoniae (S. pneumoniae) was isolated from the nasopharynx and oropharynx of eight SCD patients. Serotypes of S. pneumoniae were 19F, 23F, and 14. All isolates were susceptible to penicillin, and patients whose nasopharynx and oropharynx were colonized by S. pneumoniae had high concentrations of aspartate transaminase, alanine transaminase, and ferritin. S. pneumoniae isolated were not penicillin-resistant serotypes suggesting that the use of penicillin for prophylaxis and/or treatment of infections is safe. Our finding of colonization and laboratory evaluation in SCD patients suggests that microorganisms are involved in the modulation of chronic inflammatory. The association of colonized microorganisms and laboratorial markers suggest a new approach to these patients follow-up, and additional studies of microorganism colonization and their association with SCD patients' clinical outcome will improve control and prevention strategies.

Long-Term Engraftment and Fetal Globin Induction upon BCL11A Gene Editing in Bone-Marrow-Derived CD34+ Hematopoietic Stem and Progenitor Cells

To develop an effective and sustainable cell therapy for sickle cell disease (SCD), we investigated the feasibility of targeted disruption of the BCL11A gene, either within exon 2 or at the GATAA motif in the intronic erythroid-specific enhancer, using zinc finger nucleases in human bone marrow (BM) CD34⁺ hematopoietic stem and progenitor cells (HSPCs). Both targeting strategies upregulated fetal globin expression in erythroid cells to levels predicted to inhibit hemoglobin S polymerization. However, complete inactivation of BCL11A resulting from bi-allelic frameshift mutations in BCL11A exon 2 adversely affected erythroid enucleation. In contrast, bi-allelic disruption of the GATAA motif in the erythroid enhancer of BCL11A did not negatively impact enucleation. Furthermore, BCL11A exon 2-edited BM-CD34⁺ cells demonstrated a significantly reduced engraftment potential in immunodeficient mice. Such an adverse effect on HSPC function was not observed upon BCL11A erythroid-enhancer GATAA motif editing, because enhancer-edited CD34⁺ cells achieved robust long-term engraftment and gave rise to erythroid cells with elevated levels of fetal globin expression when chimeric BM was cultured ex vivo. Altogether, our results support further clinical development of the BCL11A erythroid-specific enhancer editing in BM-CD34⁺ HSPCs as an autologous stem cell therapy in SCD patients.

Bioinformatics and Drug Discovery

Bioinformatic analysis can not only accelerate drug target identification and drug candidate screening and refinement, but also facilitate characterization of side effects and predict drug resistance. High-throughput data such as genomic, epigenetic, genome architecture, cistromic, transcriptomic, proteomic, and ribosome profiling data have all made significant contribution to mechanismbased drug discovery and drug repurposing. Accumulation of protein and RNA structures, as well as development of homology modeling and protein structure simulation, coupled with large structure databases of small molecules and metabolites, paved the way for more realistic protein-ligand docking experiments and more informative virtual screening. I present the conceptual framework that drives the collection of these high-throughput data, summarize the utility and potential of mining these data in drug discovery, outline a few inherent limitations in data and software mining these data, point out news ways to refine analysis of these diverse types of data, and highlight commonly used software and databases relevant to drug discovery.

Ocular manifestations of sickle cell disease and genetic susceptibility for refractive errors

PURPOSE

Sickle cell disease (SCD) is the most common and serious form of an inherited blood disorder that lead to higher risk of early mortality. SCD patients are at high risk for developing multiorgan acute and chronic complications linked with significant morbidity and mortality. Some of the ophthalmological complications of SCD include retinal changes, refractive errors, vitreous hemorrhage, and abnormalities of the cornea.

MATERIALS AND METHODS

The present study includes 96 SCD patients. A dilated comprehensive eye examination was performed to know the status of retinopathy. Refractive errors were measured in all patients. In patients with >10 years of age, cycloplegia was not performed before autorefractometry. A subset of fifty patients' genotyping was done for NOS3 27-base pair (bp) variable number of tandem repeat (VNTR) and IL4 intron-3 VNTR polymorphisms using polymerase chain reaction-electrophoresis. Chi-square test was performed to test the association between the polymorphisms and refractive errors.

RESULTS

The results of the present study revealed that 63.5% of patients have myopia followed by 19.8% hyperopia. NOS3 27-bp VNTR genotypes significantly deviated from Hardy-Weinberg equilibrium (P < 0.0001). Although IL4 70-bp VNTR increased the risk of developing refractive errors, it is not statistically significant. However, NOS3 27-bp VNTR significantly reduced the risk of development of myopia.

CONCLUSION

In summary, our study documents the prevalence of refractive errors along with some retinal changes in Indian SCD patients. Further, this study demonstrates that the NOS3 VNTR contributes to the susceptibility to development of myopia in SCD cases.

Hemoglobinopathies and Leg Ulcers

Major hemoglobinopathies, including sickle cell anemia, are becoming a global health issue. Leg ulcers are the most common cutaneous manifestation of sickle cell disease and an important contributor to morbidity burden in this population. Leg ulcers following sickling disorders are extremely painful, and hard to heal. The clinical evidence for the optimal management of these ulcers is limited. Treating the cause and the strategies to prevent sickling are the mainstay of treatment. The basic principles of wound bed preparation and compression therapy is beneficial in these patients.

Haptoglobin gene polymorphisms and interleukin-6 and -8 levels in patients with sickle cell anemia

Background

Haptoglobin genotypes, and interleukin-6 and -8 participate in the pathophysiology of sickle cell anemia. The expression of cytokines is regulated by genetic mechanisms however the effect of haptoglobin polymorphisms on these cytokines is not fully understood. This study aimed to compare the frequency of haptoglobin genotypes and the interleukin-6 and -8 concentrations in sickle cell anemia patients and controls to investigate the association between haptoglobin genotypes and cytokine levels.

Methods

Sixty sickle cell anemia patients and 74 healthy individuals were analyzed. Haptoglobin genotypes were determined by multiplex polymerase chain reaction, and the interleukin-6 and -8 levels by enzyme linked immunosorbent assay. The association between haptoglobin genotypes and cytokines was investigated by statistical tests.

Results

Hp2-1 was the most common genotype in both the cases and controls while Hp1-1 was less frequent among sickle cell anemia patients. Interleukin-6 and -8 levels were higher in patients than controls (p-value <0.0001). There was no significant difference in interleukin-6 and -8 concentrations between the genotypes (p-value >0.05). A similar trend was observed among the controls.

Conclusion

Although, levels of interleukin-6 and -8 were higher in the sickle cell anemia patients, they appeared not to be related to the haptoglobin genotypes. Further investigations are necessary to identify factors responsible for increased secretion of the interleukin-6 and -8 pro-inflammatory cytokines in patients with sickle cell anemia.

Pattern of hemolysis parameters and association with fetal hemoglobin in sickle cell anemia patients in steady state

Objective

This study aimed to evaluate the influence of fetal hemoglobin (Hb F) on hemolysis biomarkers in sickle cell anemia patients.

Methods

Fifty adult sickle cell anemia patients were included in the study. All patients were taking hydroxyurea for at least six months and were followed at the outpatient clinic of a hospital in Fortaleza, Ceará, Brazil. The control group consisted of 20 hemoglobin AA individuals. The reticulocyte count was performed by an automated methodology, lactate dehydrogenase and uric acid were measured by spectrophotometry and arginase I by enzyme-linked immunosorbent assay (ELISA). The presence of Hb S was detected by high-performance liquid chromatography. The level of significance was set for a p-value <0.05.

Results

A significant increase was observed in the reticulocyte count and lactate dehydrogenase, uric acid and arginase I levels in sickle cell anemia patients compared to the control group (p-value <0.05). Patients having Hb F levels greater than 10% showed a significant decrease in the reticulocyte count, arginase I and lactate dehydrogenase. A significant decrease was observed in arginase I levels in patients taking hydroxyurea at a dose greater than 20 mg/kg/day.

Conclusion

The results of this study show that sickle cell anemia patients have increases in the hemolysis biomarkers, lactate dehydrogenase, reticulocyte count, arginase I, uric acid and increases in Hb F can reduce the reticulocyte count and arginase I and lactate dehydrogenase levels.

Interleukin-1β and interleukin-6 gene polymorphisms are associated with manifestations of sickle cell anemia

Sickle cell anemia (SCA), a disorder characterized by both acute and chronic inflammation, exhibits substantial phenotypic variability. Interleukin-1 beta (IL-1β) and IL-6 are important in acute and chronic diseases, and their single nucleotide polymorphisms (SNPs) have been considered as predictors of prognosis in several inflammatory conditions. This study aims at exploring possible association of IL-1β and IL-6 SNPs as potential genetic modifiers and or predictors of SCA clinical and laboratory phenotypes. This cross-sectional study involved 107 SCA patients and 110 age, sex and ethnicity-matched healthy individuals. The SNPs were identified by PCR-RFLP for IL-1β (-511C>T and +3954C>T) and IL-6 (-597G>A and -174G>C) genes. Associations between these SNPs and the clinical and laboratory profiles of patients with SCA were then determined. Allelic and genotypic frequencies of IL-1β and IL-6 SNPs between patients with SCA and controls were similar and followed HWE. IL-1β +3954C>T SNP was associated with increased risk of osteonecrosis, elevated pulmonary arterial pressure and lower absolute reticulocyte count, while IL-6 -597G>A was associated with higher likelihood of retinopathy and leg ulcer. These data indicate that IL-1β and IL-6 gene SNPs are associated with SCA complications among Brazilian patients and may act as genetic predictors of SCA clinical heterogeneity.

AKAP-dependent modulation of BCAM/Lu adhesion on normal and sickle cell disease RBCs revealed by force nanoscopy

Human normal and sickle red blood cells (RBCs) adhere with high affinity to the alpha5 chain of laminin (LAMA5) via the basal cell adhesion molecule/Lutheran (BCAM/Lu) receptor, which is implicated in vasoocclusive episodes in sickle cell disease and activated through the cyclic adenosine monophosphate (cAMP) signaling pathway. However, the effect of the cAMP pathway on the expression of active BCAM/Lu receptors at the single-molecule level is unknown. We established an in vitro technique, based on atomic force microscopy, which enables detection of single BCAM/Lu proteins on the RBC surface and measures the unbinding force between BCAM/Lu and LAMA5. We showed that the expression of active BCAM/Lu receptors is higher in homozygous sickle RBCs (SS-RBCs) than normal RBCs and that it is critically dependent on the cAMP signaling pathway on both normal and SS-RBCs. Of importance, we illustrated that A-kinase anchoring proteins are crucial for BCAM/Lu receptor activation. Furthermore, we found that SS-RBCs from hydroxyurea-treated patients show a lower expression of active BCAM/Lu receptors, a lower unbinding force to LAMA5, and insignificant stimulation by epinephrine as compared to SS-RBCs from untreated patients. To our knowledge, these findings may lead to novel antiadhesive targets for vasoocclusive episodes in sickle cell disease.

Hypoxia and inflammation in children with sickle cell disease: implications for hippocampal functioning and episodic memory

Children with sickle cell disease (SCD) suffer from systemic processes (e.g., chronic anemia, recurrent hypoxic-ischemic events, chronic inflammation) that have been associated with neurocognitive impairment in a range of clinical populations, but which have been largely understudied in relation to specific domains of cognitive functioning in children with SCD. This review focuses on episodic memory, as the hippocampus may be especially vulnerable to the systemic processes associated with SCD. The first part of the paper outlines the pathophysiology of SCD and briefly reviews the extant literature on academic and cognitive functioning in children with SCD, emphasizing the dearth of research on episodic memory. Next, the complex systemic processes of hypoxia and inflammation associated with SCD are reviewed, along with research that has associated these processes with hippocampal damage and memory impairment. The paper concludes with suggestions for future research that are informed, in part, by the literature on developmental amnesia.

Explaining additional genetic variation in complex traits

Genome-wide association studies (GWAS) have provided valuable insights into the genetic basis of complex traits, discovering >6000 variants associated with >500 quantitative traits and common complex diseases in humans. The associations identified so far represent only a fraction of those that influence phenotype, because there are likely to be many variants across the entire frequency spectrum, each of which influences multiple traits, with only a small average contribution to the phenotypic variance. This presents a considerable challenge to further dissection of the remaining unexplained genetic variance within populations, which limits our ability to predict disease risk, identify new drug targets, improve and maintain food sources, and understand natural diversity. This challenge will be met within the current framework through larger sample size, better phenotyping, including recording of nongenetic risk factors, focused study designs, and an integration of multiple sources of phenotypic and genetic information. The current evidence supports the application of quantitative genetic approaches, and we argue that one should retain simpler theories until simplicity can be traded for greater explanatory power.

Phenotypic effect of α-globin gene numbers on Indian sickle β-thalassemia patients

BACKGROUND

Sickle cell β-thalassemia is a compound heterozygous state of β-thalassemia and sickle cell anemia. Patient with these conditions showed mild-to-severe clinical phenotype.

OBJECTIVES

The objective of this study was to evaluate the effects of α-globin gene numbers on the phenotype of sickle cell β-thalassemia patients.

MATERIALS AND METHODS

Seventy-five sickle cell β-thalassemia patients were characterized. Clinical, hematological, and molecular characterization was performed in all subjects. Amplified refectory mutation system-polymerase chain reaction was applied for β-thalassemia mutation study while α-genotyping was conducted by Gap-PCR.

RESULTS

Highest frequency of IVS1-5 (33 out of 75 patients) β-thalassemia genotype was recorded. Twenty-eight patients were reported with α-globin chain deletion while four had α-triplications (Anti α-3.7kb). Sickle β-thalassemia patients with α-chain deletions ameliorate hematological and clinical variables.

CONCLUSIONS

This study indicates that the coexistence of α-globin chain deletions showed mild phenotype instead of absence of α-chain deletions while the patients with triplication of α-genes express severe phenotype.

Addition of multimodal therapy to standard management of steady state sickle cell disease

Most people on folic acid to boost erythropoiesis and prophylactic antimicrobials, the standard management of steady state sickle cell disease (SCD), have unacceptable numbers of crises. The objective of this study was to evaluate the effects of adding multimodal therapy with potassium thiocyanate and omega-3 fatty acids to the standard management of steady state SCD. Pre- and post-treatment numbers of crises and other disease indices were compared in 16 HbSS individuals on folic acid and paludrine after 12 months of adding eicosapentaenoic acid 15 mg/kg/day, docosahexaenoic acid 10 mg/kg/day, and potassium thiocyanate 1-2 mL/day, each milliliter of which contained 250 mg of thiocyanate and 100 micrograms of iodine to prevent hypothyroidism: a possible side-effect due to competitive inhibition of the transport of iodide into the thyroid gland by thiocyanate. Median number of crises reduced from 3/yr to 1/yr (P < 0.0001). There was no evidence of impaired thyroid function. Plasma level of tri-iodothyronine improved (P < 0.0001). Steady state full blood count and bilirubin level did not change significantly. The findings suggest that addition of potassium thiocyanate and eicosapentaenoic and docosahexaenoic acids to standard management of steady state SCD reduces the number of crises. This observation needs to be evaluated in larger studies.

An anthropometric and hematological comparison of sickle cell disease children from rural and urban areas

BACKGROUND:

Sickle cell disease (SCD) is a prevalent genetic disorder in India and the rural and urban areas experience distinctly different healthcare facilities. In view of this, a comparative study of SCD-SS pattern children of age 8–15 years from rural and urban areas of Wardha district of Central India was carried out using anthropometric and hematological parameters.

MATERIALS AND METHODS:

The data were collected using standard methods and the results showed a significant (P < 0.05) difference in the mean values for body weight, body mass index (BMI), hemoglobin, hematocrit, and white blood corpuscles (WBC). Statistical analysis of the data was done using SPSS 18.0 software. Individuals were screened by solubility test method. Sickle cell patterns (AS and SS) were determined by using electrophoresis technique.

RESULT:

The SCD-SS children from rural were significantly underweight than those from the urban area of Wardha district. BMI is a good indicator of nutritional status and BMI values of SCD children have less than desired.

CONCLUSION:

The study highlights an urgent need to conduct integrated investigations for SCD population of rural areas covering clinical, nutritional, and social aspects.

Hemorheological risk factors of acute chest syndrome and painful vaso-occlusive crisis in children with sickle cell disease

BACKGROUND

Little is known about the effects of blood rheology on the occurrence of acute chest syndrome and painful vaso-occlusive crises in children with sickle cell anemia and hemoglobin SC disease.

DESIGN AND METHODS

To address this issue, steady-state hemorheological profiles (blood viscosity, red blood cell deformability, aggregation properties) and hematologic parameters were assessed in 44 children with sickle cell anemia and 49 children with hemoglobin SC disease (8-16 years old) followed since birth. Clinical charts were retrospectively reviewed to determine prior acute chest syndrome or vaso-occlusive episodes, and rates of these complications were calculated.

RESULTS

Multivariate analysis revealed that: 1) a higher steady-state blood viscosity was associated with a higher rate of vaso-occlusive crises in children with sickle cell anemia, but not in children with hemoglobin SC disease; 2) a higher steady-state red blood cell disaggregation threshold was associated with previous history of acute chest syndrome in children with hemoglobin SC disease and boys with sickle cell anemia.

CONCLUSIONS

Our results indicate for the first time that the red blood cell aggregation properties may play a role in the pathophysiology of acute chest syndrome in children with hemoglobin SC disease and boys with sickle cell anemia. In addition, whereas greater blood viscosity is associated with a higher rate of vaso-occlusive crises in children with sickle cell anemia, no association was found in children with hemoglobin SC disease, underscoring differences in the etiology of vaso-occlusive crises between sickle cell anemia and hemoglobin SC disease.

Technical desiderata for the integration of genomic data into Electronic Health Records

The era of "Personalized Medicine," guided by individual molecular variation in DNA, RNA, expressed proteins and other forms of high volume molecular data brings new requirements and challenges to the design and implementation of Electronic Health Records (EHRs). In this article we describe the characteristics of biomolecular data that differentiate it from other classes of data commonly found in EHRs, enumerate a set of technical desiderata for its management in healthcare settings, and offer a candidate technical approach to its compact and efficient representation in operational systems.

Development and validation of a pediatric severity index for sickle cell patients

There is no instrument to measure severity of sickle cell disease (SCD) in pediatric patients that is generally accepted. The aim of this study was to develop and validate a severity index for SCD in children. We developed an index consisting of 12 items and tested its validity of the index using data from 92 children. We tested whether different scores were obtained for patients classified by severity both subjectively and objectively by a partially validated existing index. Furthermore, we tested whether the index could differentiate patients classified according to genotype or the number of α-gene deletions and evaluated whether the score on the index was correlated with the average number and days of hospitalizations/year, age and a risk of death score. We explored the effect of three different weighting systems (Score A, B, and C) to summarize these items. All weightings demonstrated a significant difference between the scores of mild, moderate, and severely affected patients, as classified by a subjective rating or with an existing index (P < 0.01). The index clearly differentiated patients by genotype (P < 0.01) or α-gene deletions (P < 0.01). The correlation with hospitalization was moderate. Age and the risk of death score were weakly associated with the pediatric severity index for SCD. This is the first pediatric SCD severity index that was developed and validated using modern clinimetric methodology. The validity and reliability of this index should be further evaluated in a prospective study including a larger cohort, preferably diagnosed at birth.

Increase in surface hydrophobicity of the cataract-associated P23T mutant of human gammaD-crystallin is responsible for its dramatically lower, retrograde solubility

The cataract-associated Pro23 to Thr (P23T) mutation in human gammaD-crystallin (HGD) has a variety of phenotypes and is geographically widespread. Therefore, there is considerable interest in understanding the molecular basis of cataract formation due to this mutation. We showed earlier [Pande, A., et al. (2005) Biochemistry 44, 2491-2500] that the probable basis of opacity in this case is the severely compromised, retrograde solubility and aggregation of P23T relative to HGD. The dramatic solubility change occurs even as the structure of the mutant protein remains essentially unchanged in vitro. We proposed that the retrograde solubility and aggregation of P23T were mediated by net hydrophobic, protein-protein interactions. On the basis of these initial findings for P23T and related mutants, and the subsequent finding that they show atypical phase behavior [McManus, J. J., et al. (2007) Proc. Natl. Acad. Sci. U.S.A. 104, 16856-16861], we concluded that the protein clusters formed in solutions of the mutant proteins were held together by net hydrophobic, anisotropic interactions. Here we show, using chemical probes, that the surface hydrophobicities of these mutants are inversely related to their solubility. Furthermore, by probing the isolated N-terminal domains of HGD and P23T directly, we find that the increase in the surface hydrophobicity of P23T is localized in the N-terminal domain. Modeling studies suggest the presence of sticky patches on the surface of the N-terminal domain that could be engaged in the formation of protein clusters via hydrophobic protein-protein interactions. This work thus provides direct evidence of the dominant role played by net hydrophobic and anisotropic protein-protein interactions in the aggregation of P23T.

Sickle-cell anemia and pulmonary hypertension

PURPOSE

To provide nurse practitioners (NPs) information about sickle-cell disease (SCD) and pulmonary hypertension (PHTN) as a complication. A case study is presented to illustrate the diagnosis of PHTN in a patient with SCD. Clinical manifestations, diagnosis, and interventions for both SCD and PHTN are also discussed.

DATA SOURCE

A literature search to support this case review was conducted in PubMed and SCOPUS using key search words. Specific information for the case study was obtained from a patient in a primary care setting.

CONCLUSION

Pulmonary hypertension is frequently diagnosed secondary to hemoglobinopathies such as SCD. Patients with sickle-cell anemia, a lifelong hereditary hemoglobinopathy, are now surviving into adulthood because of the advances made in treatment. About one third of these patients develop pulmonary hypertension, a complication that carries a 40% mortality rate. Delayed diagnosis can affect the patient's quality of life. Timely diagnosis and referral is imperative, but only if the advanced practitioner is able to recognize this common complication.

IMPLICATIONS FOR PRACTICE

Many patients with SCD are seen in primary care practices. Such is the situation for the patient in this case study. Familiarity with pulmonary hypertension secondary to SCD can increase the awareness of NPs of this potential consequence and initiate early diagnostic evaluation.

Sickle Cell Disease: A Multigenic Perspective of a Single Gene Disorder

The phenotypic heterogeneity of sickle cell disease continues to puzzle clinicians and investigators more than half a century after the elucidation of its molecular basis. Although advances have been made in understanding the influences of globin gene-related factors such as alpha-thalassemia (thal) and high Hb F determinants, these are far from providing a satisfactory explanation to the variation and clinical diversity of sickle cell disease in many cases. The sequencing of the human genome and the development of novel technologies such as high throughput genotyping and analysis of gene expression through cDNA microarrays has made it possible to investigate this diversity with these approaches and identify novel genetic modifiers of sickle cell disease. This brief review focuses on the recent advances in our understanding of the impact of non globin genetic modifiers on the phenotypic diversity of the disease.

Shadows of complexity: what biological networks reveal about epistasis and pleiotropy

Pleiotropy, in which one mutation causes multiple phenotypes, has traditionally been seen as a deviation from the conventional observation in which one gene affects one phenotype. Epistasis, or gene-gene interaction, has also been treated as an exception to the Mendelian one gene-one phenotype paradigm. This simplified perspective belies the pervasive complexity of biology and hinders progress toward a deeper understanding of biological systems. We assert that epistasis and pleiotropy are not isolated occurrences, but ubiquitous and inherent properties of biomolecular networks. These phenomena should not be treated as exceptions, but rather as fundamental components of genetic analyses. A systems level understanding of epistasis and pleiotropy is, therefore, critical to furthering our understanding of human genetics and its contribution to common human disease. Finally, graph theory offers an intuitive and powerful set of tools with which to study the network bases of these important genetic phenomena.

Platelet count as a predictor of the severity of sickle cell disease during pregnancy

Recent evidence implicates the immune system and the clotting mechanisms in the pathophysiology of sickle cell disease (SCD). This study investigates the association of steady state platelet count with the severity of SCD in pregnancy. A total of 40 SCD women who were asymptomatic early in pregnancy were studied retrospectively: 14 remained asymptomatic throughout pregnancy and 26 developed at least one SCD-related complication. The early pregnancy platelet count was compared between the two groups using t-test and its ability to predict SCD-related complications in pregnancy was investigated using Receiver-Operator Characteristics (ROC) curve. Compared with asymptomatic patients, women who developed SCD-related complications had significantly higher early-pregnancy platelet count [328x10(9)/l (95% CI: 268-389) vs 210x10(9)/l (146-275), p < 0.01]. The area under the ROC curve was 76.4% (95% CI 59.7-93.2). These indicate that the platelet count in early pregnancy is significantly higher in SCD patients who subsequently develop SCD-related complications and may be used for screening.