Safety and efficacy of monthly high-dose vitamin D3 supplementation in children and adolescents with sickle cell disease

Little is known about the impact of vitamin D supplementation on hand grip strength (HGS) and health-related quality of life (HRQoL) in children and adolescents with sickle cell disease (SCD). We aimed to evaluate the safety and efficacy of monthly high-dose vitamin D3 supplementation and its implications on bone mineral density (BMD), HGS, and HRQoL in patients with SCD and healthy controls. The study included 42 children with SCD and 42 healthy matched controls. The study participants were supplemented with high-dose monthly oral vitamin D3. Changes in the serum level of 25(OH) vitamin D3, maximum HGS, and BMD from baseline to 6 months were assessed, and the HRQoL questionnaire and Childhood Health Assessment Questionnaire (CHAQ) were used to evaluate the functional capacity. At baseline, SCD subjects had poorer growth status indicated by negative Z scores. Suboptimal BMD was detected by significantly lower Z score, and lower HGS and worse HRQL parameters were found compared to the controls (P < 0.001). Median 25(OH) vitamin D3 was significantly lower in SCD patients compared to controls (16.5 vs. 28 ng/mL, respectively (P < 0.001)). After 6 months of vitamin D supplementation, there was significant improvement in the DEXA Z-score (P < 0.001), limitation of physical health (P = 0.02), pain scores (P < 0.001), and CHAQ grades (P = 0.01) in SCD patients. A significant improvement in HGS (P < 0.001 and P = 0.005) as well as the CHAQ score (P < 0.001 and P = 0.003) was detected in the SCD group and controls, respectively. There were no reported clinical adverse events (AEs) or new concomitant medications (CMs) during the study duration, and safe levels of Ca and 25 (OH) D3 were observed at 3 and 6 months for both groups. There was a significant positive correlation between HGS and total physical score (r = 0.831, P < 0.001) and a negative correlation with CHAQ score (r =  - 0.685, P < 0.001). We also detected a significant positive correlation between vitamin D levels at 6 months and HGS (r = 0.584, P < 0.001), pain score (r = 0.446, P < 0.001), and a negative correlation with CHAQ score (r =  - 0.399, P < 0.001).   Conclusion: Monthly oral high-dose vitamin D supplementation was safe and effective in improving vitamin D levels, HGS, and HRQoL in SCD children and healthy subjects, and BMD scores in SCD patients. Further randomized controlled trials are warranted to assess an optimal dosing strategy and to investigate the impact on clinically significant outcomes in children and adolescents with SCD and their healthy counterparts.   Trial registration: ClinicalTrials.gov , identifier NCT06274203, date of registration: 23/02/2024, retrospectively registered. What is known: • Several studies have reported a high prevalence of vitamin D deficiency and suboptimal bone mineral density (BMD) in sickle cell disease (SCD) patients. • Musculoskeletal dysfunction is reported in SCD patients with a negative impact on physical activity and health-related quality of life (HRQL). • Little is known regarding the impact of vitamin D3 supplementation in children and adolescents with SCD. What is new: • We found that monthly oral high-dose vitamin D3 supplementation was safe, tolerated, and effective in improving serum vitamin D levels, HGS, BMD scores, and HRQL in SCD patients.

Sterile inflammation induces vasculopathy and chronic lung injury in murine sickle cell disease

Murine sickle cell disease (SCD) results in damage to multiple organs, likely mediated first by vasculopathy. While the mechanisms inducing vascular damage remain to be determined, nitric oxide bioavailability and sterile inflammation are both considered to play major roles in vasculopathy. Here, we investigate the effects of high mobility group box-1 (HMGB1), a pro-inflammatory damage-associated molecular pattern (DAMP) molecule on endothelial-dependent vasodilation and lung morphometrics, a structural index of damage in sickle (SS) mice. SS mice were treated with either phosphate-buffered saline (PBS), hE-HMGB1-BP, an hE dual-domain peptide that binds and removes HMGB1 from the circulation via the liver, 1-[4-(aminocarbonyl)-2-methylphenyl]-5-[4-(1H-imidazol-1-yl)phenyl]-1H-pyrrole-2-propanoic acid (N6022) or N-acetyl-lysyltyrosylcysteine amide (KYC) for three weeks. Human umbilical vein endothelial cells (HUVEC) were treated with recombinant HMGB1 (r-HMGB1), which increases S-nitrosoglutathione reductase (GSNOR) expression by ∼80%, demonstrating a direct effect of HMGB1 to increase GSNOR. Treatment of SS mice with hE-HMGB1-BP reduced plasma HMGB1 in SS mice to control levels and reduced GSNOR expression in facialis arteries isolated from SS mice by ∼20%. These changes were associated with improved endothelial-dependent vasodilation. Treatment of SS mice with N6022 also improved vasodilation in SS mice suggesting that targeting GSNOR also improves vasodilation. SCD decreased protein nitrosothiols (SNOs) and radial alveolar counts (RAC) and increased GSNOR expression and mean linear intercepts (MLI) in lungs from SS mice. The marked changes in pulmonary morphometrics and GSNOR expression throughout the lung parenchyma in SS mice were improved by treating with either hE-HMGB1-BP or KYC. These data demonstrate that murine SCD induces vasculopathy and chronic lung disease by an HMGB1- and GSNOR-dependent mechanism and suggest that HMGB1 and GSNOR might be effective therapeutic targets for reducing vasculopathy and chronic lung disease in humans with SCD.

Structure-based computational design of novel covalent binders for the treatment of sickle cell disease

The quest in finding an everlasting panacea to the pernicious impact of sickle cell disease (SCD) in the society hit a turn of success since the recent discovery of a small molecule reversible covalent inhibitor, Voxelotor. A drug that primarily promotes the stability of oxygenated hemoglobin and inhibit the polymerization of HbS by enhancing hemoglobin's affinity for oxygen has opened a new frontier in drug discovery and development. Despite eminent efforts made to reproduce small molecules with better therapeutic targets, none has been successful. To this end, we employed the use of structure-based computational techniques with emphasis on the electrophilic warhead group of Voxelotor to harness novel covalent binders that could elicit better therapeutic response against HbS. The PubChem database and DataWarrior software were used to design random molecules using Voxelotor's electrophilic functionality. Following the compilation of these chemical entities, a high-throughput covalent docking-based virtual screening campaign was conducted which revealed three (Compound_166, Compound_2301, and Compound_2335) putative druglike candidates with higher baseline energy value compared to the standard drug. Subsequently, in silico ADMET profiling was carried out to evaluate their pharmacokinetics and pharmacodynamics properties, and their stability was evaluated for 1 μs (1 μs) using molecular dynamics simulation. Finally, to prioritize these compounds for further development in drug discovery, MM/PBSA calculations was employed to evaluate their molecular interactions and solvation energy within the HbS protein. Despite the admirable druglike and stability properties of these compounds, further experimental validations are required to establish their preclinical relevance for drug development.

A Patient Presents for Dental Extraction and Goes into Sickle Cell Crisis in the Dental Chair

Sickle Cell Disease is an inherited autosomal recessive hemoglobinopathy associated with multiorgan damage. This single gene disorder involves one DNA base pair alteration, producing HbS. The sickle-shaped cells form when deoxygenated in the capillaries. The resulting RBC stasis leads to ischemia and pain, and acute and chronic organ damage. Patients with SCD presenting to a dental office need careful examination to rule out any current infections, neurologic deficits, or other organ involvement before formulating a dental treatment plan to avoid prolonged and complicated procedures. Early intervention and dental anxiety management are key to the dental treatment of patients with SCD.

Silent Cerebral Infarcts in Iraqi Patients with Sickle Cell Disease

Silent ischemic infarcts have been reported to be the most frequent neurological abnormalities in sickle cell disease (SCD) in several studies worldwide. However, no previous studies investigated this neurological disorder in Iraqi SCD patients. To address this issue, a total of 52 patients with a median age of 20 years (range 10-46) and including 46.2% males were enrolled. Patients were clinically evaluated and their records were reviewed. They had full blood and reticulocyte counts, hemoglobin F estimation, serum lactic dehydrogenase and bilirubin assayed, as well as brain magnetic resonance imaging (MRI) to screen for silent cerebral infarcts. Six out of the 52 patients (11.5%) had silent cerebral infarcts, all of which were in the deep white matter, ranging from 6 to 10 mm in their largest diameters. There were no significant differences in age, sex, or sickle cell genotype between those with silent cerebral infarcts and those without it. Those with silent cerebral infarcts had lower median hemoglobin, higher reticulocytes and lower pain frequencies than those without it, yet again this was not significant. Follow up MRI in four out of the six silent infarct patients showed no additional lesions and no increase in size of the original ones after six to eight months. In conclusion, it appears that the frequency of silent cerebral infarcts in Iraqi SCD patients is lower than the bulk of the literature from other populations. Further studies to screen for genetic polymorphisms that may explain this lower rate may be informative.

Clinical significance of mutational variants in beta and alpha genes in patients with hemoglobinopathies from two large Greek centers: a complex interplay between genotype and phenotype

Hemoglobinopathies affect patients in the wider Mediterranean area consisting of 4 distinct subgroups: beta thalassemia major (TM), beta thalassemia intermedia (TI), sickle cell disease (SCD) and hemoglobin H disease (alpha thalassemia). The clinical spectrum varies from mild to severe. Complex interactions between genes and environmental factors form the clinical manifestations. There is an unmet need to clarify these multifactorial mechanisms. This is the first Greek study describing mutational alleles (HBB and HBA1/HBA2 gene variants) in 217 patients with hemoglobinopathies of two large centers in Greece (Larissa and Athens) and associating particular genotypes or gene variants with clinical manifestations (transfusion frequency, complications). Thus, the complex interplay between corresponding genotypes and phenotypes was investigated. Our results are in accordance with previous national studies with limited variations, due to regional prevalence of specific gene variants, as expected. It is also a description of the prevalence of hemoglobinopathies in the Greek population. The type and prevalence of beta and alpha globin gene variants differ significantly among countries. We also confirm the well-known observation of many studies that in our beta thalassemic or SCD patients, co-inheritance of variants in the alpha globin genes, leading to absence or reduction of alpha globin synthesis were associated with milder clinical course, whereas the inheritance of additional alpha genes (triplication) led to a more severe clinical phenotype. In cases in whom the genotype and phenotype did not correlate, factors like the function or modification of possible regulatory genes or additional nutritional-environmental effects should be investigated. KEY MESSAGES: • This is the first Greek study, fully molecularly defining the beta and alpha mutational alleles in 217 patients with hemoglobinopathies of two large centers in Greece and correlating particular genotypes or gene variants with clinical manifestations (transfusion frequency, complications). • In the beta thalassemic or SCD patients of our cohort, co-inheritance of variants in the alpha globin genes, leading to absence or reduction of alpha globin synthesis were associated with milder clinical course (confirmation of a well-known previous observation). • The inheritance of additional alpha genes (triplication) led to a more severe clinical phenotype (confirmation of a well known previous observation). • The function or modification of possible regulatory genes should be investigated in cases in whom the genotype and phenotype did not correlate.

Comparison of CAT and short forms for PROMIS pain and physical health domains in children with sickle cell disease

BACKGROUND

Pain and physical health domains included in Patient-Reported Outcomes Measurement Information System® (PROMIS®) can be administered as short forms (SF) or as computer adaptive tests (CAT). CAT is ideal in many settings but cannot be administered without specialized technology. We compared SF and CAT to identify items for customized SFs to improve the SF performance for children with sickle cell disease (SCD).

METHODS

Eligible children 8-17 years old were administered CATs for 5 domains of physical health and 2 domains of pain, followed by any items on the corresponding SF that were not included in the CAT assessments. We describe the range of scores on the CAT and SFs, including the percentage of participants with floor or ceiling effects using the SF. The agreement and correlation between CAT and SF scores were assessed using Bland-Altman plots. Items frequently offered on CAT that had variable responses and were not already present on SF are recommended as additional items for customized SFs.

RESULTS

Among 90 children with SCD, there were strong correlations between CAT and SF scores (Concordance Correlation Coefficient > 0.8) however, the SFs for fatigue, mobility, strength impact, pain behavior, and pain interference had substantial floor/ceiling effects. Fatigue, mobility, physical stress experience, and pain behavior domains had items that were frequently offered on CAT, variable responses, and were not present on the SF.

CONCLUSIONS

Adding items to the SFs for the fatigue, mobility, physical stress experience, and pain behavior domains may improve these domains' SFs performance for children with SCD.

The efficacy of maternal health education and maternal screening on knowledge and the uptake of infant screening for sickle cell disease in Dar-Es-Salaam, Tanzania; a quasi experimental study

BACKGROUND

Globally, Sickle cell disease (SCD) is one of the most common genetic disease with high childhood mortality. Early identification of babies with SCD through newborn screening (NBS) and linking them to care are among the recommended interventions. The purpose of this study was to assess the efficacy of maternal health education and maternal screening for SCD on knowledge and the uptake of infant screening for SCD among mother-infant pairs attending antenatal clinics at Government health facilities in Dar-es-salaam, Tanzania.  METHODS: This study was a pre-test post-test, quasi-experimental which involved pregnant women attending antenatal clinics at three hospitals; Mbagala hospital, Sinza hospital and Buguruni health center in Dar Es Salaam. A structured questionnaire was used in data collection. Knowledge on SCD was assessed for all participants before and after two sessions of health education. Participants in Mbagala and Buguruni were also screened for SCD using Sickle SCAN point-of-care test (BioMedomics Inc, USA). The efficacy for health education intervention was computed as the post-intervention minus baseline knowledge score. For proportions, a two-sample z-test was used. Univariate and multivariate logistic regression were used to analyze the efficacy of health education intervention and also predictors of infant diagnosis.  RESULTS: For two sessions of health education intervention, a total of 467 pregnant women completed the sessions. During antenatal visits, a total of 218 were screened for SCD. The proportion of participants with good knowledge of SCD had significantly increased to 85.9% from 12.4% at baseline following the education intervention. In multivariate analysis, sharing the received education on SCD was an independent predictor of the efficacy of health education intervention. Maternal occupation, maternal SCD status as well as sharing the received education on SCD were independent predictors of the uptake of SCD infant diagnosis.

CONCLUSION

This study has demonstrated that maternal health education and maternal screening for SCD are feasible and efficacious interventions in raising knowledge and improving the uptake of infant diagnosis for SCD. These interventions are strongly recommended to be included in the comprehensive care package for pregnant women attending antenatal clinics, particularly in areas with a high burden of SCD.

Association of sickle cell disease with anthropometric indices among under-five children: evidence from 2018 Nigeria Demographic and Health Survey

BACKGROUND

Malnutrition continues to affect under-five children in Africa to an overwhelming proportion. The situation is further compounded by the burden of sickle cell disease (SCD). However, association of SCD with stunting, wasting, and underweight in a nationally representative sample of under-five children remains unexplored. We aimed to describe prevalence of undernutrition by sickle cell status, to evaluate its association with growth faltering ascertained by anthropometric indices, and to explore mediating role of hemoglobin.

METHODS

We availed data from the 2018 Nigeria Demographic and Health Survey (DHS) and the sample comprised 11,233 children aged 6-59 months who were successfully genotyped for SCD. The DHS employed a two-stage, stratified sampling strategy. SickleSCAN rapid diagnostic test was used for SCD genotyping. Z-scores of length/height-for-age (HAZ), weight-for-height (WHZ), and weight-for-age (WAZ) were computed against the 2006 World Health Organization Child Growth Standards. We fitted logistic regression models to evaluate association of SCD with stunting, wasting, and underweight. Mediation analysis was performed to capture the indirect effect of and proportion of total effect mediated through hemoglobin level in SCD-anthropometric indices association.

RESULTS

Prevalences of stunting, wasting, and underweight among children with SCD were 55.4% (54.5-56.4), 9.1% (8.6-9.7), and 38.9% (38.0-39.8), respectively. The odds of stunting were 2.39 times higher (adjusted odds ratio (aOR) 2.39, 95% CI: 1.26-4.54) among sickle children than those with normal hemoglobin. SCD was also significantly associated with underweight (aOR 2.64, 95% CI: 1.25-5.98), but not with wasting (aOR: 1.60, 95% CI 0.85-3.02). Association of SCD with all three anthropometric indices was significantly mediated through hemoglobin level: for SCD-HAZ, the adjusted indirect effect (aIE) was - 0.328 (95% CI: - 0.387, - 0.270); for SCD-WHZ, the aIE was - 0.080 (95% CI: - 0.114, - 0.050); and for SCD-WAZ, the aIE was - 0.245 (95% CI: - 0.291, - 0.200).

CONCLUSION

We presented compelling evidence of the negative impact of SCD on anthropometric indices of nutritional status of under-five children. Integration of a nutrition-oriented approach into a definitive SCD care package and its nationwide implementation could bring promising results by mitigating the nutritional vulnerability of children with SCD.

Feasibility of establishing a network of community health workers to support care of people with sickle cell disease in Kumasi, Ghana

Globally, sickle cell disease (SCD) is a common, yet often neglected, non-communicable disease. Community health worker (CHW) interventions have been shown to improve outcomes for chronic diseases but have not been evaluated with SCD. This study assessed the interest in and feasibility of establishing a network of CHWs to support care of people with SCD in Kumasi, Ghana. Using in-depth interviews with key stakeholders (N = 15) identified through purposive and snowball sampling from January to March 2020, we gathered focused information about interest in and feasibility of establishing a network of CHWs. Respondents were chosen for their knowledge and oversight of health services for people with SCD. Latent content analysis was used to examine the data. Participants expressed interest in establishing a network of CHWs to better support care for people with SCD. Three primary themes emerged from the data: (1) support by CHWs could be beneficial for people with SCD; (2) using existing CHW networks for SCD services would be best; and (3) funding of expanded CHW network might be a problem. We advocate for the mobilization of resources to expand the current network of CHWs to include a focus on SCD in Kumasi, Ghana. Participants believe that it is feasible to use CHWs to improve care outcomes of people with SCD. There is potential for findings from this exploratory project to be adapted and implemented in other settings throughout sub-Saharan Africa, as well as areas of higher income countries where there are higher proportions of people living with sickle cell.

Influence of rs1042713 and rs1042714 polymorphisms of β2-adrenergic receptor gene with erythrocyte cAMP in sickle cell disease patients from Odisha State, India

The vaso-occlusive crisis (VOCs) in sickle cell disease (SCD) is often associated with stress. Epinephrine released during stress acts via beta 2-adrenergic receptors (β2-AR or ADRB2) to stimulate the synthesis of cyclic adenosine monophosphate (cAMP) in the red blood cells (RBCs). Higher cAMP levels promote adhesion of sickled RBCs to vascular endothelium, a major contributor for VOCs. Several single-nucleotide polymorphisms (SNPs) of the β2-AR gene have been reported; two of them at codon 16 (rs1042713) and codon 27 (rs1042714) have been extensively studied for their clinical relevance. Therefore, we assessed the influence of polymorphism at these two sites of the β2-AR gene on the RBC cAMP concentrations with and without epinephrine stimulation in SCD subjects. We determined the frequency distribution of different genotypes of codon 16 and codon 27 of the β2-AR gene using the Sanger sequencing method in the SCD subjects. We measured the RBC-cAMP levels at baseline and after stimulation with epinephrine, to ascertain the influence of different genotypes in determining cAMP levels. There was no difference in the socio-demographic and hematological indicators in different genotypes of both codon 16 and 27. In the sham-treated erythrocytes, the cAMP levels were significantly different with three genotypes of codon 16 (F = 3.39, P = 0.036; one way ANOVA) but not with different genotypes of codon 27. A significant increase in cAMP levels was noticed with epinephrine treatment in all genotypes of codons 16 and 27 (P = 0.001; Wilcoxon signed-rank test). However, the extent of increase in the epinephrine-treated cAMP values from the sham-treated (baseline) cAMP values was significantly different between the three genotypes of codon 16 (H = 8.74; P = 0.012; Kruskal-Wallis test) but not in codon 27 genotypes. Polymorphism in codon 16 (rs1042713) of the β2-AR gene influences cAMP concentrations in the RBC both before and after epinephrine treatment. Higher cAMP levels may lead to increased adhesion of sickle cell RBCs to vascular endothelium and may increase the frequency of VOCs.

Design, synthesis, and optimization of a series of 2-azaspiro[3.3]heptane derivatives as orally bioavailable fetal hemoglobin inducers

Pharmacological reactivation of the γ-globin gene for the production of fetal hemoglobin (HbF) is a promising approach for the management of β-thalassemia and sickle cell disease (SCD). We conducted a phenotypic screen in human erythroid progenitor cells to identify molecules that could induce HbF, which resulted in identification of the hit compound 1. Exploration of structure-activity relationships and optimization of ADME properties led to 2-azaspiro[3.3]heptane derivative 18, which is more rigid and has a unique structure. In vivo using cynomolgus monkeys, compound 18 induced a significant dose-dependent increase in globin switching, with developable properties. Moreover, compound 18 showed no genotoxic effects and was much safer than hydroxyurea. These findings could facilitate the development of effective new therapies for the treatment of β-hemoglobinopathies, including SCD.

Pathophysiology and recent therapeutic insights of sickle cell disease

Sickle cell disease (SCD) is an autosomal recessive blood disorder which occurs due to point mutation in the β-globin chain of hemoglobin. Since the past decades, various therapies have been put forth, which are based on obstructing pathophysiological mechanisms of SCD including inhibition of Gardos channel and cation fluxes which in turn prevents sickle erythrocyte destruction and dehydration. The pharmacological approaches are based on the mechanism of reactivating γ-globin expression by utilizing fetal hemoglobin (HbF)-inducing drugs such as hydroxyurea. In SCD, gene therapy could be considered as a promising tool which involves modifying mutation at the gene-specific target by either promoting insertion or deletion of globins. Although there are various therapies emerged so far in the treatment of SCD, many of them have faced a major setback in most of developing countries in terms of cost, unavailability of expertise, and suitable donor. Therefore, in addition to pathophysiological aspects, this review will discuss new advancements and approaches made in the therapeutic domain of SCD including a viewpoint of modulating hemoglobin in SCD by the intervention of probiotics.

Caring for Africa's sickle cell children: will we rise to the challenge?

BACKGROUND

Most of the world's sickle cell disease (SCD) burden is in Africa, where it is a major contributor to child morbidity and mortality. Despite the low cost of many preventive SCD interventions, insufficient resources have been allocated, and progress in alleviating the SCD burden has lagged behind other public-health efforts in Africa. The recent announcement of massive new funding for research into curative SCD therapies is encouraging in the long term, but over the next few decades, it is unlikely to help Africa's SCD children substantially.

MAIN DISCUSSION

A major barrier to progress has been the absence of large-scale early-life screening. Most SCD deaths in Africa probably occur before cases are even diagnosed. In the last few years, novel inexpensive SCD point-of-care test kits have become widely available and have been deployed successfully in African field settings. These kits could potentially enable universal early SCD screening. Other recent developments are the expansion of the pneumococcal conjugate vaccine towards near-universal coverage, and the demonstrated safety, efficacy, and increasing availability and affordability of hydroxyurea across the continent. Most elements of standard healthcare for SCD children that are already proven to work in the West, could and should now be implemented at scale in Africa. National and continental SCD research and care networks in Africa have also made substantial progress, assembling care guidelines and enabling the deployment and scale-up of SCD public-health systems. Substantial logistical, cultural, and awareness barriers remain, but with sufficient financial and political will, similar barriers have already been overcome in efforts to control other diseases in Africa.

CONCLUSION AND RECOMMENDATIONS

Despite remaining challenges, several high-SCD-burden African countries have the political will and infrastructure for the rapid implementation and scale-up of comprehensive SCD childcare programs. A globally funded effort starting with these countries and expanding elsewhere in Africa and to other high-burden countries, including India, could transform the lives of SCD children worldwide and help countries to attain their Sustainable Development Goals. This endeavor would also require ongoing research focused on the unique needs and challenges of SCD patients, and children in particular, in regions of high prevalence.

Anemias

Anemias continue to present a challenge to the health care profession. Anemia is defined as a reduction in one or more of the RBC indices. Patients presenting with a mild form of anemia may be asymptomatic; however, in more serious cases the anemia can become life threatening. In many cases the clinical presentation also reflects the underlying cause. Anemia may be attributed to various causes, whereas autoimmune RBC destruction may be attributed to intrinsic and extrinsic factors. Laboratory tests are essential in facilitating early detection and differentiation of anemia.