Klotho Level as a Marker of Low Bone Mineral Density in Egyptian Sickle Cell Disease Patients.

Bone involvement of sickle cell disease (SCD) patients varies from acute clinical manifestations of painful vaso-occlusive crises or osteomyelitis to more chronic affection of bone mineral density (BMD) and debilitating osteonecrosis and osteoporosis. Secreted klotho protein is involved in calcium (Ca) reabsorption in the kidney. This study aimed to measure serum klotho levels in children with SCD to determine the possibility of using it as a marker of low BMD in children with SCD in correlation with a dual-energy radiograph absorptiometry scan. This study included 60 sickle disease patients and 30 age-matched and sex-matched control participants without SCD. A highly statistically significant difference was found between patients with normal BMD and those with low BMD, with serum Ca and klotho levels being lower in the latter group. Klotho serum level correlated positively with both serum Ca and BMD. Serum klotho level showed 94.9% sensitivity and 95.2% specificity in the detection of low BMD. Both serum Ca and klotho serum levels may be useful markers for detection of low BMD related to SCD with high sensitivity and specificity; however, klotho may be a better indicator as it is less affected by the nutritional and endocrinal status of patients or by intake of Ca supplements.

A pilot study of the effect of rivaroxaban in sickle cell anemia.

INTRODUCTION: The contribution of coagulation activation to the pathogenesis of sickle cell disease (SCD) remains incompletely defined. We evaluated the efficacy and safety of rivaroxaban, an oral direct factor Xa inhibitor, in subjects with sickle cell anemia. MATERIALS AND METHODS: In this pilot, single-center, randomized, double-blind, placebo-controlled, crossover study, eligible subjects with sickle cell anemia received rivaroxaban or placebo. The effect of rivaroxaban on coagulation activation, endothelial activation, inflammation, and microvascular blood flow was evaluated. RESULTS: Fourteen patients (HbSS - 14; females - 9) with mean age of 38 ± 10.6 years were randomized to receive rivaroxaban 20 mg daily or placebo for 4 weeks and, following a 2-week washout phase, were "crossed-over" to the treatment arm opposite to which they were initially assigned. Mean adherence to treatment with rivaroxaban, assessed by pill counts, was 85.6% in the first treatment period and 93.6% in the second period. Treatment with rivaroxaban resulted in a decrease from baseline of thrombin-antithrombin complex versus placebo (-34.4 ug/L [95% CI: -69.4, 0.53] vs. 0.35 ug/L [95% CI: -3.8, 4.5], p = .08), but the difference was not statistically significant. No significant differences were observed in changes from baseline of D-dimer, inflammatory, and endothelial activation markers or measures of microvascular blood flow. Rivaroxaban was well tolerated. CONCLUSIONS: Rivaroxaban was safe but did not significantly decrease coagulation activation, endothelial activation, or inflammation. Rivaroxaban did not improve microvascular blood flow. Adequately powered studies are required to further evaluate the efficacy of rivaroxaban in SCD. Clinicaltrials.gov Identifier: NCT02072668.

Anti-sickling activities of two isolated compounds from the root of Combretum racemosum P. beauv. (Combretaceae).

ETHNOPHARMACOLOGICAL RELEVANCE: Evaluation of plants such as Combretum racemosum with claimed traditional use in the management of sickle cell anaemia in Nigeria and other parts of West Africa could serve as a useful research strategy in the search for potential anti-sickling drugs and templates. AIM OF THE STUDY: This study aimed at evaluating the antisickling potential of C. racemosum by activity-guided purification and isolation of its active constituents. MATERIALS AND METHODS: Crude methanol extract of the root of C. racemosum and the fractions obtained by partitioning with chloroform, ethyl acetate, and aqueous were investigated for anti-sickling activity against sodium metabisulphite induced sickling of sickle cell haemoglobin (HbSS). Repeated chromatographic separations were conducted on the most active chloroform fraction to purify and isolate bioactive compounds for further tests for anti-sickling activity. The characterization of the isolated compounds was done by mass spectrometry (FD+MS) and nuclear magnetic resonance (1HNMR) spectroscopy. RESULTS: The chloroform fraction (FA) (% sickled erythrocyte ranged from 3.0 to 34.1) exhibited better anti-sickling activity than aqueous (% sickled erythrocyte ranged from 38.9 to 51.5) as well as the crude methanol (% sickled erythrocyte ranged from 19.1 to 30.4). Hence, the phytochemical investigation was focused on the chloroform fraction, which led to the identification of two ellagic acid derivatives (3,3',4'-tri-O-methyl ellagic acid (A) and 3,3'-di-O- methyl ellagic acid (B). The two isolated compounds possessed good, comparable anti-sickling activities with compound A exhibiting a slightly better in vitro activity. CONCLUSION: This paper reports for the first time anti-sickling principles from C. racemosum and therefore, provided some justification for the ethnomedicinal use of the plant in the management of sickle cell disease.

Quail (Coturnix japonica) egg attenuated 2-butoxyethanol-induced enzymatic dysregulation, disseminated thrombosis and hemolytic impairment in female wistar rats.

Influence of quail egg on pathologies has increased research interests and series of investigations are currently being done on its influence against these pathologies. The influence of quail egg against 2-butoxyethanol induced hemolysis and disseminated thrombosis was investigated to determine the enzymatic regulations that ensue in the amelioration of deleterious hemolytic and disseminated thrombosis displayed in female Wistar rats. Quail egg was separated into three (3) components (extracts)-quail egg yolk water soluble (QYWS) and fat soluble (QYFS), and albumen extract (QA) and the inorganic and organic compositions were characterized. Depranocytotic assaults was achieved by 250 mg/kg of 2-Butoxyethanol administered for 4 days, the clinical observation revealed a dark purple-red discoloration on the distal tails of the rats and therapeutic applications followed with 1000 mg/kg BWT of QYWS, QYFS and QA, and 15 mg/kg BWT of hydroxyurea. Morphological evaluation, haematological estimations and biochemical evaluations of the influence on the activities of sphingosine kinase-1, RNase, red cell carbonic anhydrase, lactate dehydrogenase, glutathione peroxidase and caspase-3, vis a vis the concentrations of sphingosine-1 phosphate, selenium and zinc (plasma and urine). In vitro anti-inflammatory influence of quail egg components were investigated against hemolysis and key enzymes of inflammation-cycloxygenase, lipoxygenase and ß-glucuronidase. The in vitro anti-inflammatory effects of QYWS, QYFS and QA were concentration dependent from 200 to 800 µg/ml against hemolysis and the key enzymes of inflammation. The characterization of inorganic and organic bioactive composition of the yolk and albumen revealed the presence of folic acid, cobalamin, pyridine, riboflavin, ascorbic acid as well as vitamins D and E, selenium, zinc, iron and calcium. These had reflected in the attenuation of the induced hemolytic and disseminated thrombosis by regulations of enzymes linked to the infarction, apoptosis and oxidative stress characterized in sickle cell index.

Comparison of two vitamin D supplementation strategies in children with sickle cell disease: a randomized controlled trial.

Previously, we showed that nearly 70% of children followed in our sickle cell disease (SCD) clinic were vitamin D- deficient and had low vitamin intake with poor use of supplements. We compared the change in serum 25-hydroxyvitamin D [25(OH)D], safety and clinical impact of two vitamin D supplementation regimens in children with SCD. Children (5-17 years, all genotypes) were randomized to a single bolus of vitamin D3 (300 000 IU; n = 18) or placebo (n = 20). All children received a prescription for daily 1 000 IU vitamin D3 . Serum 25(OH)D and calcium, urinary calcium/creatinine ratio, musculoskeletal pain, quality of life, haematology and bone markers were assessed at baseline and three months post intervention. Bolus administration led to a greater rise in 25(OH)D levels from baseline compared to placebo (20 ± 16 nmol/l vs. 2 ± 19 nmol/l; P = 0·003) and correction of vitamin D deficiency. No hypercalcaemia nor hypercalciuria occurred during the study, but more children in the bolus group experienced gastrointestinal symptoms within the first month (P = 0·04). There were no differences between groups for other outcomes. The use of a high-dose vitamin D bolus combined with daily 1 000 IU vitamin D3 was more efficient in raising 25(OH)D levels than daily supplementation alone in children with SCD.

VZHE-039, a novel antisickling agent that prevents erythrocyte sickling under both hypoxic and anoxic conditions.

Sickle cell disease (SCD) results from a hemoglobin (Hb) mutation ßGlu6 → ßVal6 that changes normal Hb (HbA) into sickle Hb (HbS). Under hypoxia, HbS polymerizes into rigid fibers, causing red blood cells (RBCs) to sickle; leading to numerous adverse pathological effects. The RBC sickling is made worse by the low oxygen (O2) affinity of HbS, due to elevated intra-RBC concentrations of the natural Hb effector, 2,3-diphosphoglycerate. This has prompted the development of Hb modifiers, such as aromatic aldehydes, with the intent of increasing Hb affinity for O2 with subsequent prevention of RBC sickling. One such molecule, Voxelotor was recently approved by U.S. FDA to treat SCD. Here we report results of a novel aromatic aldehyde, VZHE-039, that mimics both the O2-dependent and O2-independent antisickling properties of fetal hemoglobin. The latter mechanism of action-as elucidated through crystallographic and biological studies-is likely due to disruption of key intermolecular contacts necessary for stable HbS polymer formation. This dual antisickling mechanism, in addition to VZHE-039 metabolic stability, has translated into significantly enhanced and sustained pharmacologic activities. Finally, VZHE-039 showed no significant inhibition of several CYPs, demonstrated efficient RBC partitioning and high membrane permeability, and is not an efflux transporter (P-gp) substrate.

Iron stores in pregnant women with sickle cell disease: a systematic review.

BACKGROUND: Gradual improvements in the management of sickle cell disease (SCD), have led to an increase in the number of women with SCD who reach the age of procreation. However, evidence on the iron status of pregnant women with sickle cell disease (PWSCD) remains inconclusive. We conducted the first systematic review on the prevalence, determinants and maternal/foetal outcomes of iron deficiency anaemia among PWSCD. METHODS: We searched MEDLINE, EMBASE, Global Health, Africa Index Medicus, the Cochrane library databases and reference lists of retrieved publications for studies describing the iron status of PWSCD. The literature search was done over a period of 1 month, with no language or date restrictions applied. Data were extracted on a Microsoft excel sheet. Two authors assessed all included studies for methodological quality and risk of bias. RESULTS: A total of 710 reports were identified for title and article screening. Five retained studies were conducted before or during the 90s and included 67 participants. After quality assessment, the observational studies were designated to have a "fair" quality assessment while the randomised control trial had an "unclear" quality assessment. The prevalence of iron deficiency anaemia among PWSCD varied by study design and diagnostic method. The overall prevalence ranged from 6.67-83.33%. None of the studies provided evidence on factors associated with iron deficiency anaemia and the randomized trial reported no difference in outcomes between PWSCD who had iron supplementation and those who did not. CONCLUSION: Evidence on factors associated with iron deficiency anaemia among PWSCD and maternal/foetal outcomes in PWSCD who have iron deficiency anaemia is poor. The studies included in this review suggests that iron deficiency anaemia may be highly prevalent in PWSCD but due to the very small sample sizes and varied study designs, this evidence is inconclusive. The review shows that there is a need for more studies with robust designs and adequate sample sizes to assess the disease burden of iron deficiency anaemia in PWSCD.

Discovery of Novel Fetal Hemoglobin Inducers through Small Chemical Library Screening.

The screening of chemical libraries based on cellular biosensors is a useful approach to identify new hits for novel therapeutic targets involved in rare genetic pathologies, such as ß-thalassemia and sickle cell disease. In particular, pharmacologically mediated stimulation of human γ-globin gene expression, and increase of fetal hemoglobin (HbF) production, have been suggested as potential therapeutic strategies for these hemoglobinopathies. In this article, we screened a small chemical library, constituted of 150 compounds, using the cellular biosensor K562.GR, carrying enhanced green fluorescence protein (EGFP) and red fluorescence protein (RFP) genes under the control of the human γ-globin and ß-globin gene promoters, respectively. Then the identified compounds were analyzed as HbF inducers on primary cell cultures, obtained from ß-thalassemia patients, confirming their activity as HbF inducers, and suggesting these molecules as lead compounds for further chemical and biological investigations.

In vitro assessment of the anti-sickling properties of Buchholzia coriacea and Mucuna pruriens seed extracts.

Sickle cell disease is a group of diseases inherited through the gene and it affects the haemoglobin in the red blood cell. This study investigated the methanol seed extract of Buchholzia coriacea for possible in vitro anti-sickling effects and also determined the effect of Mucuna pruriens seed extract on the solubility and oxygen-binding rate of sickle cell haemoglobin. Sickle cell blood was collected from sickle cell disease patients with subsequent addition of 2% sodium metabisulphite to cause more sickling. Varying concentrations of the seed extracts (50%, 25%, 12.5% and 6.25%) were added to the pre-treated blood for these in vitro assays. The results showed that the extract of Buchholzia coriacea significantly (P < 0.05) inhibited sickling at all concentrations with the highest percentage inhibition of 73.3 ± 5.8, reversed sickled erythrocytes at all concentrations with the highest percentage reversal of 83.3 ± 5.8 and significantly (P < 0.05) inhibited polymerisation at all concentrations used in comparison to the parallel control. The extract of Mucuna pruriens seed significantly (P < 0.05) increased the solubility of sickle haemoglobin at 50%, 25%, 12.5% and 6.25% concentrations, increased Fe2+/Fe3+ ratio from 1.7 (control) to 12.2 (50% concentration) and reduced osmotic fragility (at 12.5% and 6.25% concentrations) when compared with parallel control. The results indicate the feasibility of the seed extracts as promising agents in the management of sickle cell disease.

Phytomedicines (medicines derived from plants) for sickle cell disease.

BACKGROUND: Sickle cell disease, a common recessively inherited haemoglobin disorder, affects people from sub-Saharan Africa, the Middle East, Mediterranean basin, Indian subcontinent, Caribbean and South America. It is associated with complications and a reduced life expectancy. Phytomedicines (medicine derived from plants in their original state) encompass many of the plant remedies from traditional healers which the populations most affected would encounter. Laboratory research and limited clinical trials have suggested positive effects of phytomedicines both in vivo and in vitro. However, there has been little systematic appraisal of their benefits. This is an updated version of a previously published Cochrane Review. OBJECTIVES: To assess the benefits and risks of phytomedicines in people with sickle cell disease of all types, of any age, in any setting. SEARCH METHODS: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Trials Register, the International Standard Randomised Controlled Trial Number Register (ISRCTN), the Allied and Complimentary Medicine Database (AMED), ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). Dates of most recent searches: Cochrane Cystic Fibrosis and Genetic Disorders Haemoglobinopathies Trials Register: 17 March 2020; ISRCTN: 19 April 2020; AMED: 18 May 2020; ClinicalTrials.gov: 24 April 2020; and the WHO ICTRP: 27 July 2017. SELECTION CRITERIA: Randomised or quasi-randomised trials with participants of all ages with sickle cell disease, in all settings, comparing the administration of phytomedicines, by any mode to placebo or conventional treatment, including blood transfusion and hydroxyurea. DATA COLLECTION AND ANALYSIS: Both authors independently assessed trial quality and extracted data. MAIN RESULTS: Three trials (212 participants) of three phytomedicines: Niprisan® (also known as Nicosan®), Ciklavit® and a powdered extract of Pfaffia paniculata were included. The Phase IIB (pivotal) trial suggests that Niprisan® may be effective in reducing episodes of severe painful sickle cell disease crisis over a six-month period (low-quality evidence). It did not appear to affect the risk of severe complications or the level of anaemia (low-quality evidence). The single trial of Cajanus cajan (Ciklavit®) reported a possible benefit to individuals with painful crises, and a possible adverse effect (non-significant) on the level of anaemia (low-quality evidence). We are uncertain of the effect of Pfaffia paniculata on the laboratory parameters and symptoms of SCD (very low-quality of evidence). No adverse effects were reported with Niprisan® and Pfaffia paniculata (low- to very low-quality evidence). AUTHORS' CONCLUSIONS: While Niprisan® appeared to be safe and effective in reducing severe painful crises over a six-month follow-up period, further trials are required to assess its role in managing people with SCD and the results of its multicentre trials are awaited. Currently, no conclusions can be made regarding the efficacy of Ciklavit® and the powdered root extract of Pfaffia paniculata in managing SCD. Based on the published results for Niprisan® and in view of the limitations in data collection and analysis of the three trials, phytomedicines may have a potential beneficial effect in reducing painful crises in SCD. This needs to be further validated in future trials. More trials with improved study design and data collection are required on the safety and efficacy of phytomedicines used in managing SCD.

Automated exchange compared to manual and simple blood transfusion attenuates rise in ferritin level after 1 year of regular blood transfusion therapy in chronically transfused children with sickle cell disease.

BACKGROUND: Optimal strategies for regular blood transfusion therapy are not well defined in sickle cell disease (SCD). This analysis tested the hypothesis that in the first of year of regular transfusions, when chelation therapy use is minimal, automated exchange transfusion would be the superior method for attenuating the rise in ferritin levels compared to simple and manual exchange transfusions. STUDY DESIGN AND METHODS: The Silent Cerebral Infarct Multi-Center Clinical Trial randomly allocated children with SCD and silent cerebral infarcts to receive standard care or regular transfusions with a target pre-transfusion HbS concentration ≤ 30% and minimum hemoglobin level > 9.0 g/dL. Participants with at least nine transfusions and sufficient ferritin testing in the first year of the trial were included in a planned secondary analysis. Ferritin levels by the end of the first study year were compared between participants receiving automatic exchange transfusion, manual exchange transfusion, and simple transfusion. RESULTS: A total of 83 participants were analyzed. During the first year of the study, 75.9% of the participants had >80% of transfusions via one transfusion method. At baseline no significant differences in ferritin levels were observed in the three transfusion groups (p = 0.1). After 1 year of transfusions the median (interquartile range) ferritin levels in the simple transfusion (n = 40), manual exchange transfusion (n = 34) and automatic exchange transfusion (n = 9) groups were 1800 ng/mL (1426-2204 ng/mL), 1530 ng/mL (1205-1805 ng/mL), and 355 ng/mL (179-579 ng/mL), respectively (p < 0.001). CONCLUSION: Automated exchange transfusion, when compared to other transfusion methods, is the optimal transfusion strategy for attenuating increase in ferritin levels in children with SCD.

Folic acid supplementation in children with sickle cell disease: study protocol for a double-blind randomized cross-over trial.

BACKGROUND: Sickle cell disease (SCD) is a genetic disorder which causes dysfunctional red blood cells (RBC) and is thought to increase requirements for folate, an essential B vitamin, due to increased RBC production and turnover in the disease. High-dose supplementation with 1-5 mg/d folic acid, synthetic folate, has been the standard recommendation for children with SCD. There is concern about whether children with SCD need such high doses of folic acid, following mandatory folic acid fortification of enriched grains in Canada, and advancements in medical therapies which extend the average lifespan of RBCs. In animal and human studies, high folic acid intakes (1 mg/d) have been associated with accelerated growth of some cancers, and the biological effects of circulating unmetabolized folic acid (UMFA), which can occur with doses of folic acid ≥ 0.2 mg/d, are not fully understood. The objective of this study is to determine efficacy of, and alterations in folate metabolism from high-dose folic acid in children with SCD during periods of folic acid supplementation versus no supplementation. METHODS: In this double-blind randomized controlled cross-over trial, children with SCD (n = 36, aged 2-19 years) will be randomized to either receive 1 mg/d folic acid, the current standard of care, or a placebo for 12 weeks. After a 12-week washout period, treatments will be reversed. Total folate concentrations (serum and RBC), different folate forms (including UMFA), folate-related metabolites, and clinical outcomes will be measured at baseline and after treatment periods. The sum of the values measured in the two periods will be calculated for each subject and compared across the two sequence groups by means of a test for independent samples for the primary (RBC folate concentrations) and secondary (UMFA) outcomes. Dietary intake will be measured at the beginning of each study period. DISCUSSION: As the first rigorously designed clinical trial in children with SCD, this trial will inform and assess current clinical practice, with the ultimate goal of improving nutritional status of children with SCD. TRIAL REGISTRATION: ClinicalTrials.gov NCT04011345 . Registered on July 8, 2019.

Blood transfusion for preventing primary and secondary stroke in people with sickle cell disease.

BACKGROUND: Sickle cell disease is one of the commonest severe monogenic disorders in the world, due to the inheritance of two abnormal haemoglobin (beta globin) genes. Sickle cell disease can cause severe pain, significant end-organ damage, pulmonary complications, and premature death. Stroke affects around 10% of children with sickle cell anaemia (HbSS). Chronic blood transfusions may reduce the risk of vaso-occlusion and stroke by diluting the proportion of sickled cells in the circulation. This is an update of a Cochrane Review first published in 2002, and last updated in 2017. OBJECTIVES: To assess risks and benefits of chronic blood transfusion regimens in people with sickle cell disease for primary and secondary stroke prevention (excluding silent cerebral infarcts). SEARCH METHODS: We searched for relevant trials in the Cochrane Library, MEDLINE (from 1946), Embase (from 1974), the Transfusion Evidence Library (from 1980), and ongoing trial databases; all searches current to 8 October 2019. We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Trials Register: 19 September 2019. SELECTION CRITERIA: Randomised controlled trials comparing red blood cell transfusions as prophylaxis for stroke in people with sickle cell disease to alternative or standard treatment. There were no restrictions by outcomes examined, language or publication status. DATA COLLECTION AND ANALYSIS: Two authors independently assessed trial eligibility and the risk of bias and extracted data. MAIN RESULTS: We included five trials (660 participants) published between 1998 and 2016. Four of these trials were terminated early. The vast majority of participants had the haemoglobin (Hb)SS form of sickle cell disease. Three trials compared regular red cell transfusions to standard care in primary prevention of stroke: two in children with no previous long-term transfusions; and one in children and adolescents on long-term transfusion. Two trials compared the drug hydroxyurea (hydroxycarbamide) and phlebotomy to long-term transfusions and iron chelation therapy: one in primary prevention (children); and one in secondary prevention (children and adolescents). The quality of the evidence was very low to moderate across different outcomes according to GRADE methodology. This was due to the trials being at a high risk of bias due to lack of blinding, indirectness and imprecise outcome estimates. Red cell transfusions versus standard care Children with no previous long-term transfusions Long-term transfusions probably reduce the incidence of clinical stroke in children with a higher risk of stroke (abnormal transcranial doppler velocities or previous history of silent cerebral infarct), risk ratio 0.12 (95% confidence interval 0.03 to 0.49) (two trials, 326 participants), moderate quality evidence. Long-term transfusions may: reduce the incidence of other sickle cell disease-related complications (acute chest syndrome, risk ratio 0.24 (95% confidence interval 0.12 to 0.48)) (two trials, 326 participants); increase quality of life (difference estimate -0.54, 95% confidence interval -0.92 to -0.17) (one trial, 166 participants); but make little or no difference to IQ scores (least square mean: 1.7, standard error 95% confidence interval -1.1 to 4.4) (one trial, 166 participants), low quality evidence. We are very uncertain whether long-term transfusions: reduce the risk of transient ischaemic attacks, Peto odds ratio 0.13 (95% confidence interval 0.01 to 2.11) (two trials, 323 participants); have any effect on all-cause mortality, no deaths reported (two trials, 326 participants); or increase the risk of alloimmunisation, risk ratio 3.16 (95% confidence interval 0.18 to 57.17) (one trial, 121 participants), very low quality evidence. Children and adolescents with previous long-term transfusions (one trial, 79 participants) We are very uncertain whether continuing long-term transfusions reduces the incidence of: stroke, risk ratio 0.22 (95% confidence interval 0.01 to 4.35); or all-cause mortality, Peto odds ratio 8.00 (95% confidence interval 0.16 to 404.12), very low quality evidence. Several review outcomes were only reported in one trial arm (sickle cell disease-related complications, alloimmunisation, transient ischaemic attacks). The trial did not report neurological impairment, or quality of life. Hydroxyurea and phlebotomy versus red cell transfusions and chelation Neither trial reported on neurological impairment, alloimmunisation, or quality of life. Primary prevention, children (one trial, 121 participants) Switching to hydroxyurea and phlebotomy may have little or no effect on liver iron concentrations, mean difference -1.80 mg Fe/g dry-weight liver (95% confidence interval -5.16 to 1.56), low quality evidence. We are very uncertain whether switching to hydroxyurea and phlebotomy has any effect on: risk of stroke (no strokes); all-cause mortality (no deaths); transient ischaemic attacks, risk ratio 1.02 (95% confidence interval 0.21 to 4.84); or other sickle cell disease-related complications (acute chest syndrome, risk ratio 2.03 (95% confidence interval 0.39 to 10.69)), very low quality evidence. Secondary prevention, children and adolescents (one trial, 133 participants) Switching to hydroxyurea and phlebotomy may: increase the risk of sickle cell disease-related serious adverse events, risk ratio 3.10 (95% confidence interval 1.42 to 6.75); but have little or no effect on median liver iron concentrations (hydroxyurea, 17.3 mg Fe/g dry-weight liver (interquartile range 10.0 to 30.6)); transfusion 17.3 mg Fe/g dry-weight liver (interquartile range 8.8 to 30.7), low quality evidence. We are very uncertain whether switching to hydroxyurea and phlebotomy: increases the risk of stroke, risk ratio 14.78 (95% confidence interval 0.86 to 253.66); or has any effect on all-cause mortality, Peto odds ratio 0.98 (95% confidence interval 0.06 to 15.92); or transient ischaemic attacks, risk ratio 0.66 (95% confidence interval 0.25 to 1.74), very low quality evidence. AUTHORS' CONCLUSIONS: There is no evidence for managing adults, or children who do not have HbSS sickle cell disease. In children who are at higher risk of stroke and have not had previous long-term transfusions, there is moderate quality evidence that long-term red cell transfusions reduce the risk of stroke, and low quality evidence they also reduce the risk of other sickle cell disease-related complications. In primary and secondary prevention of stroke there is low quality evidence that switching to hydroxyurea with phlebotomy has little or no effect on the liver iron concentration. In secondary prevention of stroke there is low-quality evidence that switching to hydroxyurea with phlebotomy increases the risk of sickle cell disease-related events. All other evidence in this review is of very low quality.

Vitamin D supplementation for sickle cell disease.

BACKGROUND: Sickle cell disease (SCD) is a genetic chronic haemolytic and pro-inflammatory disorder. With increased catabolism and deficits in energy and nutrient intake, individuals with SCD suffer multiple macro- and micro-nutritional deficiencies, including vitamin D deficiency. This is an update of a previous review. OBJECTIVES: To investigate the effects of vitamin D supplementation in children and adults with SCD and to compare different dose regimens. To determine the effects of vitamin D supplementation on general health (e.g. growth status and health-related quality of life), on musculoskeletal health (including bone mineral density, pain crises, bone fracture and muscle health), on respiratory health (including lung function, acute chest syndrome, acute exacerbation of asthma and respiratory infections) and the safety of vitamin D supplementation. SEARCH METHODS: We searched the Cochrane Haemoglobinopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. Date of last search: 19 March 2020. We also searched database such as PubMed, clinical trial registries and the reference lists of relevant articles and reviews. Date of last search: 14 January 2020. SELECTION CRITERIA: Randomised controlled trials (RCTs) and quasi-RCTs comparing oral administration of any form of vitamin D supplementation at any dose and for any duration to another type or dose of vitamin D or placebo or no supplementation in people with SCD, of all ages, gender, and phenotypes. DATA COLLECTION AND ANALYSIS: Two authors independently extracted the data and assessed the risk of bias of the included studies. They used the GRADE guidelines to assess the quality of the evidence. MAIN RESULTS: Vitamin D versus placebo One double-blind RCT (n = 39) compared oral vitamin D3 (cholecalciferol) supplementation (20 participants) to placebo (19 participants) for six weeks. Only 25 participants completed the full six months of follow-up. The study had a high risk of bias due to incomplete outcome data, but a low risk of bias for randomisation, allocation concealment, blinding (of participants, personnel and outcome assessors) and selective outcome reporting; and an unclear risk of other biases. Vitamin D supplementation probably led to higher serum 25(OH)D levels at eight weeks, mean difference (MD) 29.79 (95% confidence interval (CI) 26.63 to 32.95); at 16 weeks, MD 12.67 (95% CI 10.43 to 14.90); and at 24 weeks, MD 15.52 (95% CI 13.50 to 17.54) (moderate-quality evidence). There was little or no difference in adverse events (tingling of lips or hands) between the vitamin D and placebo groups, risk ratio 3.16 (95% CI 0.14 to 72.84) (low-quality evidence). Vitamin D supplementation probably caused fewer pain days compared to the placebo group at eight weeks, MD -10.00 (95% CI -16.47 to -3.53) (low-quality evidence), but probably led to a lower (worse) health-related quality of life score (change from baseline in physical functioning PedsQL scores); at both 16 weeks, MD -12.56 (95% CI -16.44 to -8.69) and 24 weeks, MD -12.59 (95% CI -17.43 to -7.76), although this may not be the case at eight weeks (low-quality evidence). Vitamin D supplementation regimens compared Two double-blind RCTs (83 participants) compared different regimens of vitamin D. One RCT (n = 62) compared oral vitamin D3 7000 IU/day to 4000 IU/day for 12 weeks, while the second RCT (n = 21) compared oral vitamin D3 100,000 IU/month to 12,000 IU/month for 24 months. Both RCTs had low risk of bias for blinding (of participants, personnel and outcome assessors) and incomplete outcome data, but the risk of selective outcome reporting bias was high. The bias from randomisation and allocation concealment was low in one study but not in the second. There was an unclear risk of other biases. When comparing oral vitamin D 100,000 IU/month to 12,000 IU/month, the higher dose may have resulted in higher serum 25(OH)D levels at one year, MD 16.40 (95% CI 12.59 to 20.21) and at two years, MD 18.96 (95% CI 15.20 to 22.72) (low-quality evidence). There was little or no difference in adverse events between doses (low-quality evidence). There were more episodes of acute chest syndrome in the high-dose group, at one year, MD 0.27 (95% CI 0.02 to 0.52) but there was little or no difference at two years, MD 0.09 (95% CI -0.04 to 0.22) (moderate-quality evidence). At one year and two years there was also little or no difference between the doses in the presence of pain (moderate-quality evidence) or forced expiratory volume in one second % predicted. However, the high-dose group had lower values for % predicted forced vital capacity at both one and two years, MD -7.20% predicted (95% CI -14.15 to -0.25) and MD -7.10% predicted (95% CI -14.03 to -0.17), respectively. There were little or no differences between dose regimens in the muscle health of either hand or the dominant hand. The study comparing oral vitamin D3 7000 IU/day to 4000 IU/day (21 participants) did not provide data for analysis, but median serum 25(OH)D levels were reported to be lower in the low-dose group at both six and 12 weeks. At 12 weeks the median serum parathyroid hormone level was lower in the high-dose group. AUTHORS' CONCLUSIONS: We included three RCTs of varying quality. We consider that the current evidence presented in this review is not of sufficient quality to guide clinical practice. Until further evidence becomes available, clinicians should consider the relevant existing guidelines for vitamin D supplementation and dietary reference intakes for calcium and vitamin D. Well-designed RCTs of parallel design, are required to determine the effects and the safety of vitamin D supplementation as well as to assess the relative benefits of different doses in children and adults with SCD.

Inhibition of Band 3 tyrosine phosphorylation: a new mechanism for treatment of sickle cell disease.

Many hypotheses have been proposed to explain how a glutamate to valine substitution in sickle haemoglobin (HbS) can cause sickle cell disease (SCD). We propose and document a new mechanism in which elevated tyrosine phosphorylation of Band 3 initiates sequelae that cause vaso-occlusion and the symptoms of SCD. In this mechanism, denaturation of HbS and release of heme generate intracellular oxidants which cause inhibition of erythrocyte tyrosine phosphatases, thus permitting constitutive tyrosine phosphorylation of Band 3. This phosphorylation in turn induces dissociation of the spectrin-actin cytoskeleton from the membrane, leading to membrane weakening, discharge of membrane-derived microparticles (which initiate the coagulation cascade) and release of cell-free HbS (which consumes nitric oxide) and activates the endothelium to express adhesion receptors). These processes promote vaso-occlusive events which cause SCD. We further show that inhibitors of Syk tyrosine kinase block Band 3 tyrosine phosphorylation, prevent release of cell-free Hb, inhibit discharge of membrane-derived microparticles, increase sickle cell deformability, reduce sickle cell adhesion to human endothelial cells, and enhance sickle cell flow through microcapillaries. In view of reports that imatinib (a Syk inhibitor) successfully treats symptoms of sickle cell disease, we suggest that Syk tyrosine kinase inhibitors warrant repurposing as potential treatments for SCD.

Homocysteine is associated with severity of microvasculopathy in sickle cell disease patients.

The pathophysiology of sickle cell disease (SCD) includes vasculopathy as well as anaemia. Elevated plasma homocysteine is a risk factor for vascular disease and may be associated with increased risk of vascular complications in SCD patients. In the present study, microvascular characteristics were assessed in the bulbar conjunctiva of 18 paediatric and 18 adult SCD patients, using the non-invasive technique of computer-assisted intravital microscopy. A vasculopathy severity index (SI) was computed to quantify the degree of microvasculopathy in each patient. Plasma homocysteine and several of its determinants [serum folate and vitamin B12, plasma pyridoxal-5'-phosphate (vitamin B6 status) and creatinine (kidney function)] were measured. Age was strongly correlated with microvasculopathy in the SCD patients, with the SI increasing about 0·1 unit per one-year increase in age (P < 0·001). After adjusting for age, gender, B-vitamin status and creatinine, homocysteine concentration was directly correlated with severity index (P < 0·05). Age and homocysteine concentration were independent predictors of microvasculopathy in SCD patients. It remains to be determined whether lowering homocysteine concentrations using appropriate B-vitamin supplements (folate and vitamins B12 and B6) - particularly if started early in life - could ameliorate microvasculopathy and its associated complications in SCD patients.

Hydroxyurea can be used in children with sickle cell disease and cerebral vasculopathy for the prevention of chronic complications? A meta-analysis.

We conducted a systematic review for evaluating the impact of hydroxyurea and chronic blood transfusion in children with sickle cell disease (SCD). A search was done in four databases from inception to 2017. Trials enrolling pediatric patients with SCD and cerebral vasculopathy with or without previous episode of stroke and that reported outcomes of occurrence of stroke and other events were included. Trained reviewers determined eligibility, risk of bias, and abstracted data. Random-effects meta-analysis was conducted. We found that the primary outcome was the occurrence of stroke. We found two trials that recruited 254 patients. No difference was found for confirmed stroke occurrence (risk difference 0.04 [95% CI: -0.03 to 0.03]) and for new-onset neurological deficit (risk difference 0.11 [95% CI: -0.00 to 0.21]). Transfusions provided a significant lower risk of vaso-occlussive crisis (risk difference 0.10 [95% CI: 0.001 to 0.20]). Finally, transfusions provided a lower risk of having high concentrations of abnormal hemoglobin S (mean difference 37.94 [95% CI: 27.55 to 48.32]). As a conclusion, transfusions plus chelation therapy might be used instead of hydroxyurea in children with SCD. There is a lack of high-quality research in the care of children with SCD, and therefore a call for action is needed.

Indications for RBC Exchange Transfusion in Patients with Sickle Cell Disease: Revisited.

Clinically, sickle cell disease (SCD) is characterized by chronic hemolytic anemia, recurrent acute vaso-occlusive crises, and progressive multi-organ failure. The management for SCD varies greatly among patients, and in the same patient longitudinally. Some patients may benefit from minimal therapy and infrequent transfusions, while others are transfusion dependent. Transfusion therapy can consist of simple transfusions, which often lead to iron overload and require iron chelation therapy. Simple transfusion, however, cannot reduce HbS levels rapidly, which may be required in certain critical conditions such as acute chest syndrome (ACS) or stroke. On the other hand, red blood cell exchange transfusion (RBCEX) can prevent iron overload and achieve rapid HbS reduction. In RBCEX, the red blood cells (RBCs) of the patient are replaced with normal RBCs, and the removed plasma is returned to the patient with minimal alteration. Plasma of patients with SCD is known to contain increased levels of several inflammatory mediators in the steady state that increase during crises. This finding explains why some patients with severe complications do not respond to RBCEX, but do much better after using plasma exchange in addition to RBCEX, as previously reported. Based on this, a revision of the indications for RBCEX in patents with SCD is recommended. DISCUSSION: In the 1980s and 1990s we used the Haemonetics Corporation's V-50 machine to perform intermittent whole blood (WB) exchange to treat severe complications of sickle cell disease (SCD.) The results were excellent, as previously described [1].

Serum Folate Levels in Patients with Chronic Hemolytic Anemia on Regular Folic Acid Supplementation Before and After Dose Modification.

OBJECTIVE: In light of the recommendation of folic acid supplementation in chronic hemolytic anemia, with possible supratherapeutic dosing and associated side effects, we performed this study to investigate serum folate levels in children with chronic hemolytic anemia. METHODS: Phase 1 was a cross-sectional study of 134 patients in the Pediatric Hematology service, documenting daily dosage and performing serum folate levels. In phase 2, we reduced the dose to 1 mg for 148 patients and repeated the testing after six months. RESULTS: We found very high serum folate levels with Phase 1, with 93.2% above the upper level of normal. In Phase 2, values remained high with 42.5% above the acceptable upper limit. CONCLUSION: Doses of folic acid given to sickle cell and thalassemia patients exceed their actual needs. This should be re-evaluated to strike a balance between benefit and harm, with close monitoring of serum folate levels.

Alterations in serum levels of copper, zinc, and selenium among children with sickle cell anemia

Background/aim: Oxidative stress contributes to pathophysiological dysfunction in sickle cell anemia (SCA). Copper (Cu) is a prooxidant, whereas zinc (Zn) and selenium (Se) are antioxidant trace elements. This study investigates the serum levels of Cu, Zn, and Se among children with SCA. Materials and methods: This cross-sectional study was performed at King Khalid University Hospital, Riyadh. Thirty-three children with SCA in steady state and 33 age- and sex-matched normal healthy children were included in the study. Cu, Zn, and Se levels were measured by inductively coupled plasma-mass spectrometry (ICP-MS) instrument. Results: The median serum Cu levels among SCA patients (1.3 µg/mL) were higher than those of the controls (0.88 µg/mL; P < 0.0001). Zn (0.61 µg/mL) and Se (74 ng/mL) levels among SCA patients, however, were significantly lower than those of the controls (0.94 µg/mL; P < 0.0001) and (91.2 ng/mL; P < 0.0001), respectively. The Cu/Zn ratio among SCA patients (1.92) was higher than that of the controls (0.98). Conclusion: Decreased blood levels of antioxidant trace elements may contribute to the pathophysiology in SCA by promoting oxidative stress. The monitoring of trace element levels in SCA appears to be vital for decreasing morbidity associated with the disorder.