Global, regional, and national prevalence and mortality burden of sickle cell disease, 2000-2021: a systematic analysis from the Global Burden of Disease Study 2021

A miniaturized wash-free microfluidic assay for electrical impedance-based assessment of red blood cell-mediated microvascular occlusion

The production of HbS - an abnormal hemoglobin (Hb) - in sickle cell disease (SCD) results in poorly deformable red blood cells (RBCs) that are prone to microcapillary occlusion, causing tissue ischemia and organ damage. Novel treatments, including gene therapy, may reduce SCD morbidity, but methods to functionally evaluate RBCs remain limited. Previously, we presented the microfluidic impedance red cell assay (MIRCA) for rapid assessment of RBC deformability, employing electrical impedance-based readout to measure RBC occlusion of progressively narrowing micropillar openings. We describe herein the design, development, validation, and clinical utility of the next-generation MIRCA assay, featuring enhanced portability, rapidity, and usability. It incorporates a miniaturized impedance analyzer and features a simplified wash-free operation that yields an occlusion index (OI) within 15 min as a new metric for RBC occlusion. We show a correlation between OI and percent fetal hemoglobin (%HbF), other laboratory biomarkers of RBC hemolysis, and SCD severity. To demonstrate the assay's versatility, we tested RBC samples from treatment-naïve SCD patients in Uganda that yielded OI levels similar to those from hydroxyurea (HU)-treated patients in the U.S., highlighting the role of %HbF in protecting against microcapillary occlusion independent of other pharmacological effects. The MIRCA assay could also identify a subset of HU-treated patients with high occlusion risks, suggesting that they may require treatment adjustments including a second-line therapy to improve their outcomes. This work demonstrates the potential of the MIRCA assay for accelerated evaluation of RBC health, function, and therapeutic effect in an ex vivo model of the microcapillary networks.

Impacts of oxidative stress and anti-oxidants on the development, pathogenesis, and therapy of sickle cell disease: A comprehensive review

Sickle cell disease (SCD) is the most severe monogenic hemoglobinopathy caused by a single genetic mutation that leads to repeated polymerization and depolymerization of hemoglobin resulting in intravascular hemolysis, cell adhesion, vascular occlusion, and ischemia-reperfusion injury. Hemolysis causes oxidative damage indirectly by generating reactive oxygen species through various pathophysiological mechanisms, which include hemoglobin autoxidation, endothelial nitric oxide synthase uncoupling, reduced nitric oxide bioavailability, and elevated levels of asymmetric dimethylarginine. Red blood cells have a built-in anti-oxidant system that includes enzymes like sodium dismutase, catalase, and glutathione peroxidase, along with free radical scavenging molecules, such as vitamin C, vitamin E, and glutathione, which help them to fight oxidative damage. However, these anti-oxidants may not be sufficient to prevent the effects of oxidative stress in SCD patients. Therefore, in line with a recent FDA request that the focus to be placed on the development of innovative therapies for SCD that address the root cause of the disease, there is a need for therapies that target oxidative stress and restore redox balance in SCD patients. This review summarizes the current state of knowledge regarding the role of oxidative stress in SCD and the potential benefits of anti-oxidant therapies. It also discusses the challenges and limitations of these therapies and suggests future directions for research and development.

Sickle cell disease and infertility risks: implications for counseling and care of affected girls and women

INTRODUCTION

Sickle cell disease (SCD), its treatments and cures present infertility risks. Fertility counseling is broadly indicated for affected girls and women and fertility preservation may appeal to some. Several streams of evidence suggest that the reproductive lifespan of women with SCD is reduced. Pregnancy is associated with high miscarriage rates. There are enduring questions about the effects of highly effective hydroxyurea treatment on female fertility. Current conditioning regimens for gene therapy or hematopoietic stem cell transplant are gonadotoxic. Fertility preservation methods exist as non-experimental standards of care for girls and women. Clinicians are challenged to overcome multifactorial barriers to incorporate fertility counseling and fertility preservation care into routine SCD care.

AREAS COVERED

Here we provide a narrative review of existing evidence regarding fertility and infertility risks in girls and women with SCD and consider counseling implications of existing evidence.

EXPERT OPINION

Addressing fertility for girls and women with SCD requires engaging concerns that emerge across the lifespan, acknowledging uncertainty and identifying barriers to care, some of which may be insurmountable without public policy changes. The contemporary SCD care paradigm can offer transformative SCD treatments alongside comprehensive counselling that addresses fertility risks and fertility preservation opportunities.

Biased agonism of protease-activated receptor-1 regulates thromboinflammation in murine sickle cell disease

ABSTRACT

Sickle cell disease (SCD) is a hereditary hemoglobinopathy marked by hemolytic anemia and vaso-occlusive events (VOEs). Chronic endothelial activation, inflammation, and coagulation activation contribute to vascular congestion, VOEs, and end-organ damage. Coagulation proteases such as thrombin and activated protein C (APC) modulate inflammation and endothelial dysfunction by activating protease-activated receptor 1 (PAR1), a G-protein-coupled receptor. Thrombin cleaves PAR1 at Arg41, while APC cleaves PAR1 at Arg46, initiating either proinflammatory or cytoprotective signaling, respectively, a signaling conundrum known as biased agonism. Our prior research established the role of thrombin and PAR1 in vascular stasis in an SCD mouse model. However, the role of APC and APC-biased PAR1 signaling in thrombin generation, inflammation, and endothelial activation in SCD remains unexplored. Inhibition of APC in SCD mice increased thrombin generation, inflammation, and endothelial activation during both steady state and tumor necrosis factor α challenge. To dissect the individual contributions of thrombin-PAR1 and APC-PAR1 signaling, we used transgenic mice with point mutations at 2 PAR1 cleavage sites, ArgR41Gln (R41Q) imparting insensitivity to thrombin and Arg46Gln (R46Q) imparting insensitivity to APC. Sickle bone marrow chimeras expressing PAR1-R41Q exhibited reduced thrombo-inflammatory responses compared with wild type PAR1 or PAR1-R46Q mice. These findings highlight the potential benefit of reducing thrombin-dependent PAR1 activation while preserving APC-PAR1 signaling in SCD thromboinflammation. These results also suggest that pharmacological strategies promoting biased PAR1 signaling could effectively mitigate vascular complications associated with SCD.

Metabolic Bone Diseases Affecting Tooth Eruption: A Narrative Review

Tooth eruption is an essential process for the development of the oral and maxillofacial system. Several inherited and acquired diseases might affect this tightly regulated process, resulting in premature, delayed, or even failed tooth eruption. The purpose of this article is to review the literature and the clinical parameters of metabolic bone diseases that affect tooth eruption. It examines the physiological aspects of tooth eruption and the pathophysiological changes induced by metabolic bone diseases, including changes in bone metabolism, density, and structure. The search strategy for this review included an electronic search in PubMed, Google Scholar, Medline, Scopus, and the Cochrane Library using the following keywords: "metabolic bone diseases", "tooth eruption", "delayed tooth eruption", and each reported disease in combination with "tooth eruption disorders", covering publications up to March 2024 and limited to English-language sources. Understanding the influence of metabolic bone diseases on tooth eruption is crucial for managing both dental and skeletal manifestations associated with these disorders. This review suggests that a multidisciplinary approach to treatment may significantly improve oral outcomes for patients suffering from such conditions. Clinicians should be aware of the specific dental abnormalities that may arise and consider comprehensive evaluations and individualized treatment plans. These findings underscore the need for further research into targeted therapies that address these abnormalities.

Screening for sickle cell disease: focus on newborn investigations

Drepanocytosis is a genetic disease relevant for its epidemiological, clinical and socio-economic aspects. In our country the prevalence is highly uneven with peaks in former malaria areas, but migration flows in recent years have led to significant changes. In this document we review the screening programs currently existing in Italy with particular emphasis on newborn screening, which in other countries around the world, including within Europe, is at most universal and mandatory. The essential laboratory issues are reviewed, from sampling aspects (cord blood or peripheral), to the analytical (analytical methods dedicated to neonatal screening and adult carrier detection) and post analytical (reporting, informative) ones. An economic analysis based on data collected in the province of Modena is also proposed, clearly showing that neonatal screening is also beneficial from an economic point of view.

Reviewing the impact of hydroxyurea on DNA methylation and its potential clinical implications in sickle cell disease

Hydroxyurea (HU) is the most common drug therapy for sickle cell disease (SCD). The clinical benefits of HU derive from its upregulation of fetal hemoglobin (HbF), which reduces aggregation of the mutated sickle hemoglobin protein (HbS) and reduces SCD symptoms and complications. However, some individuals do not respond to HU, or stop responding over time. Unfortunately, current understanding of the mechanism of action of HU is limited, hindering the ability of clinicians to identify those patients who will respond to HU and to optimize treatment for those receiving HU. Given that epigenetic modifications are essential to erythropoiesis and HbF expression, we hypothesize that some effects of HU may be mediated by epigenetic modifications, specifically DNA methylation. However, few studies have investigated this possibility and the effects of HU on DNA methylation remain relatively understudied. In this review, we discuss the evidence linking HU treatment to DNA methylation changes and associated gene expression changes, with an emphasis on studies that were performed in individuals with SCD. Overall, although HU can affect DNA methylation, research on these changes and their clinical effects remains limited. Further study is likely to contribute to our understanding of hematopoiesis and benefit patients suffering from SCD.

Determinants of the haemoglobin level in patients with sickle cell disease living in sub-Saharan Africa: Major impact of the country of residence and independent effects of leucocyte and platelet counts and haemolysis

The degree of anaemia in sickle cell disease (SCD) is a well-known contributor to morbidity and mortality. We aimed to explore the factors affecting haemoglobin (Hb) level in African SCD patients, considering haemolysis biomarkers (LDH and bilirubin level, and reticulocyte count), leucocyte and platelet counts and socio-demographic characteristics (gender, age group, country of residence and BMI). The research was part of the CADRE multinational cohort and involved 3699 SCD patients living in Mali, Senegal, Ivory Coast, Democratic Republic of Congo, Gabon and Cameroon: 2936 SS/Sβ0, 587 SC and 176 Sβ + patients with median Hb level of 8, 11.3 and 11.2 g/dL respectively (p < 0.001). In multivariate analysis conducted in 1394 SS/Sβ0 patients, living in Cameroon, female gender, lower BMI, higher haemolysis markers (especially LDH) and higher leucocyte and platelet counts were independently associated with lower Hb level (all p < 0.05). In 497 SC and 156 Sβ + patients, female gender (p < 0.001), lower BMI (p < 0.05) and higher platelet counts (p < 0.001) were independently associated with lower Hb level. Anaemia in African SCD patients is not only associated with haemolysis but also with the country of residence, lower BMI and leucocyte or platelet counts which might reflect inflammation related to infectious burden in the region.

Hydroxyurea dose optimisation for children with sickle cell anaemia in sub-Saharan Africa (REACH): extended follow-up of a multicentre, open-label, phase 1/2 trial

BACKGROUND

Realizing Effectiveness Across Continents with Hydroxyurea (REACH) is an open-label non-randomised trial of hydroxyurea (hydroxycarbamide) in children with sickle cell anaemia in sub-Saharan Africa. The short-term results of REACH on safety, feasibility, and effectiveness of hydroxyurea were published previously. In this paper we report results from extended hydroxyurea treatment in the REACH cohort up to 8 years.

METHODS

In this open-label, non-randomised, phase 1/2 trial, participants were recruited from four clinical sites in Kilifi, Kenya; Mbale, Uganda; Luanda, Angola; and Kinshasa, Democratic Republic of Congo. Eligible children were 1-10 years old with documented haemoglobin SS or haemoglobin Sβ zero thalassaemia, weighing at least 10 kg. Participants received fixed-dose hydroxyurea of 17.5 (±2.5) mg/kg per day for 6 months (fixed-dose phase), followed by 6 months of dose escalation (2·5-5·0 mg/kg increments every 8 weeks) as tolerated, up to 20-35 mg/kg per day (maximum tolerated dose; MTD), defined as mild myelosuppression. After the MTD was reached, hydroxyurea dosing was optimised for each participant on the basis of changes in bodyweight and laboratory values over time (MTD with optimisation phase). After completion of the first 12 months, children with an acceptable toxicity profile and favourable responses were given the opportunity to continue hydroxyurea until the age of 18 years. The safety and feasibility results after 3 years has been reported previously. Here, haematological responses, clinical events, and toxicity rates were compared across the dosing phases (fixed-dose hydroxyurea vs MTD with optimisation phase) as protocol-specified outcomes. REACH is registered on ClinicalTrials.gov (NCT01966731) and is ongoing.

FINDINGS

We enrolled 635 children between July 4, 2014, and Nov 11, 2016. 606 children were given hydroxyurea and 522 (86%; 266 [51%] boys and 256 [49%] girls) received treatment for a median of 93 months (IQR 84-97) with 4340 patient-years of treatment. The current (Oct 5, 2023) mean dose is 28·2 (SD 5·2) mg/kg per day with an increased mean haemoglobin concentration (7·3 [SD 1·1] g/dL at baseline to 8·5 [1·5] g/dL) and mean fetal haemoglobin level (10·9% [SD 6·8] to 23·3% [9·5]) and decreased absolute neutrophil count (6·8 [3·0] × 109 cells per L to 3·6 [2·2] × 109 cells per L). Incidence rate ratios (IRR) comparing MTD with fixed-dose hydroxyurea indicate decreased vaso-occlusive episodes (0·60; 95% CI 0·52-0·70; p<0·0001), acute chest syndrome events (0·21; 0·13-0·33; p<0·0001), recurrent stroke events (0·27; 0·07-1·06; p=0·061), malaria infections (0·58; 0·46-0·72; p<0·0001), non-malarial infections (0·52; 0·46-0·58; p<0·0001), serious adverse events (0·42; 0·27-0·67; p<0·0001), and death (0·70; 0·25-1·97; p=0·50). Dose-limiting toxicity rates were similar between the fixed-dose (24·1 per 100 patient-years) and MTD phases (23·2 per 100 patient-years; 0·97; 0·70-1·35; p=0·86). Grade 3 and 4 adverse events were infrequent (18·5 per 100 patient-years) and included malaria infection, non-malarial infections, vaso-occlusive pain, and acute chest syndrome. Serious adverse events were uncommon (3·6 per 100 patient-years) and included malaria infections, parvovirus-associated anaemia, sepsis, and stroke, with no treatment-related deaths.

INTERPRETATION

Hydroxyurea dose escalation to MTD with dose optimisation significantly improved clinical responses and treatment outcomes, without increasing toxicities in children with sickle cell anaemia in sub-Saharan Africa.

FUNDING

US National Heart, Lung, and Blood Institute and Cincinnati Children's Research Foundation.

Beyond pulmonary embolism: Alternative diagnosis and incidental findings on CT pulmonary angiography in sickle cell disease

BACKGROUND

Sickle cell disease (SCD) is a genetic hematological disorder associated with severe complications, such as vaso-occlusive crises, acute chest syndrome (ACS), and an increased risk of thromboembolic events, including pulmonary embolism (PE). The diagnosis of PE in SCD patients presents challenges due to the overlapping symptoms with other pulmonary conditions. Our previous study revealed that nearly 96% of computed tomography pulmonary angiography (CTPA) scans in SCD patients were negative for PE, highlighting a gap in understanding the significance of CTPA findings when PE is absent.

METHODS

In this retrospective follow-up study conducted at the Salmaniya Medical Complex in Bahrain, we examined SCD patients with HbSS genotypes who underwent CTPA from January 1, 2018, to December 31, 2021, for suspected PE, but the results were negative. The aim of this study was to identify alternative diagnoses and incidental findings from CTPA scans. Experienced radiologists reviewed the CTPA images and reports to assess potential alternative diagnoses and incidental findings, incorporating an additional analysis of chest X-rays to evaluate the diagnostic value of CTPA. Incidental findings were classified based on their location and clinical significance.

RESULTS

Among the 230 evaluated SCD patients (average age 39.7 years; 53% male) who were CTPA negative for PE, 142 (61.7%) had identifiable alternative diagnoses, primarily pneumonia (49.1%). Notably, 88.0% of these alternative diagnoses had been previously suggested by chest radiographs. Furthermore, incidental findings were noted in 164 (71.3%) patients, with 11.0% deemed clinically significant, necessitating immediate action, and 87.8% considered potentially significant, requiring further assessment. Notable incidental findings included thoracic abnormalities such as cardiomegaly (12.2%) and an enlarged pulmonary artery (11.3%), as well as upper abdominal pathologies such as hepatomegaly (19.6%), splenomegaly (20.9%), and gallstones (10.4%).

CONCLUSION

This study underscores the limited additional diagnostic yield of CTPA for identifying alternative diagnoses to PE in SCD patients, with the majority of diagnoses, such as pneumonia, already suggested by chest radiographs. The frequent incidental findings, most of which necessitate further evaluation, highlight the need for a cautious and tailored approach to using CTPA in the SCD population.

Ex vivo culture resting time impacts transplantation outcomes of genome-edited human hematopoietic stem and progenitor cells in xenograft mouse models

Ex vivo resting culture is a standard procedure following genome editing in hematopoietic stem and progenitor cells (HSPCs). However, prolonged culture may critically affect cell viability and stem cell function. We investigated whether varying durations of culture resting times impact the engraftment efficiency of human CD34+ HSPCs edited at the BCL11A enhancer, a key regulator in the expression of fetal hemoglobin. We employed electroporation to introduce CRISPR-Cas9 components for BCL11A enhancer editing and compared outcomes with nonelectroporated (NEP) and electroporated-only (EP) control groups. Post-electroporation, we monitored cell viability, death rates, and the frequency of enriched hematopoietic stem cell (HSC) fractions (CD34+CD90+CD45RA- cells) over a 48-hour period. Our findings reveal that while the NEP group showed an increase in cell numbers 24 hours post-electroporation, both EP and BCL11A-edited groups experienced significant cell loss. Although CD34+ cell frequency remained high in all groups for up to 48 hours post-electroporation, the frequency of the HSC-enriched fraction was significantly lower in the EP and edited groups compared to the NEP group. In NBSGW xenograft mouse models, both conditioned with busulfan and nonconditioned, we found that immediate transplantation post-electroporation led to enhanced engraftment without compromising editing efficiency. Human glycophorin A+ (GPA+) red blood cells (RBCs) sorted from bone marrow of all BCL11A edited mice exhibited similar levels of γ-globin expression, regardless of infusion time. Our findings underscore the critical importance of optimizing the culture duration between genome editing and transplantation. Minimizing this interval may significantly enhance engraftment success and minimize cell loss without compromising editing efficiency. These insights offer a pathway to improve the success rates of genome editing in HSPCs, particularly for conditions like sickle cell disease.

A Pharmacist-Managed Hydroxyurea Prescribing Protocol Improves Uptake and Optimization among Patients with Sickle Cell Disease

Sickle cell disease (SCD) is a common genetic disorder with potentially serious sequelae that can be effectively treated with hydroxyurea. Despite its favorable benefit-risk profile, hydroxyurea uptake in patients with SCD is low. A pilot study was conducted at the Southern Alberta Rare Blood and Bleeding Disorders (SARBBDs) Comprehensive Care Program between January 2020 and September 2023 to assess the implementation of a pharmacist-led protocol for supporting the uptake of hydroxyurea among eligible patients with SCD and optimizing its dosing. The protocol standardized the prescription, monitoring, dose titration, and patient counselling by a clinic pharmacist. The number of patients enrolled in the SARBBDs program increased from 98 in January 2020 to 168 in 2023. During this period, the proportion of patients on hydroxyurea increased from 37.8% to 62.5%, the proportion of patients on hydroxyurea who were at a maximum tolerated dose (MTD) increased from 35.1% to 63.8%, and the average hemoglobin F level increased from 13.9% to 19.7%. The mean time to reach MTD was 10 months and required eight pharmacist interventions, six laboratory assessments, and three dose increases. Hydroxyurea continuation rates were high, with most discontinuations resulting from loss to follow-up or transition to a transfusion management strategy. This real-world pilot study demonstrated that implementation of a pharmacist-led prescribing and monitoring protocol nearly doubled hydroxyurea uptake and achievement of MTD in patients with SCD managed in a rare blood disorders clinic.

End Organ Affection in Sickle Cell Disease

Sickle cell disease is an orphan disease affecting ethnic minorities and characterized by profound systemic manifestations. Although around 100,000 individuals with SCD are living in the US, the exact number of individuals is unknown, and it is considered an orphan disease. This single-gene disorder leads to red blood cell sickling and the deoxygenation of hemoglobin, resulting in hemolysis. SCD is associated with acute complications such as vaso-occlusive crisis, infections, and chronic target organ complications such as pulmonary disease and renal failure. While genetic therapy holds promise to alter the fundamental disease process, the major challenge in the field remains the target end organ damage and ways to mitigate or reverse it. Here, we provide an overview of the clinical manifestations and pathogenesis with a focus on end-organ damage and current therapeutic options, including recent FDA-approved stem cell and gene editing therapies.

Pseudoxanthoma elasticum - Genetics, pathophysiology, and clinical presentation

Pseudoxanthoma elasticum (PXE) is an autosomal-recessively inherited multisystem disease. Mutations in the ABCC6-gene are causative, coding for a transmembrane transporter mainly expressed in hepatocytes, which promotes the efflux of adenosine triphosphate (ATP). This results in low levels of plasma inorganic pyrophosphate (PPi), a critical anti-mineralization factor. The clinical phenotype of PXE is characterized by the effects of elastic fiber calcification in the skin, the cardiovascular system, and the eyes. In the eyes, calcification of Bruch's membrane results in clinically visible lesions, including peau d'orange, angioid streaks, and comet tail lesions. Frequently, patients must be treated for secondary macular neovascularization. No effective therapy is available for treating the cause of PXE, but several promising approaches are emerging. Finding appropriate outcome measures remains a significant challenge for clinical trials in this slowly progressive disease. This review article provides an in-depth summary of the current understanding of PXE and its multi-systemic manifestations. The article offers a detailed overview of the ocular manifestations, including their morphological and functional consequences, as well as potential complications. Lastly, previous and future clinical trials of causative treatments for PXE are discussed.

Predictors of health-related quality of life in a large cohort of adult patients living with sickle cell disease in France: the DREPAtient study

Background

Sickle cell disease (SCD) is an inherited autosomal recessive disorder exhibiting a range of symptoms and acute and/or chronic complications that affect the quality of life. This study aimed to assess health-related quality of life (HRQoL) and to identify the associated factors in adult patients with SCD in France.

Methods

DREPAtient is a cross-sectional, multicenter study conducted from June 2020 to April 2021 in France and in certain French overseas territories where SCD is highly prevalent. Sociodemographic and clinical data were collected online. HRQoL was assessed by the French version of the 36-Item Short Form Survey (SF-36) questionnaire. HRQoL determinants were identified using multivariable linear regression analysis.

Results

In total, 570 participants were included, mostly women (68.9%), with a mean age of 33.3 (±10.7) years. The highest mean score HRQoL was found in the Physical functioning domain (67.5 ± 21.8) and the lowest mean score in the General Health perception domain (37.7 ± 20.3). The mean score of the physical composite (PCS) and mental composite (MCS) of SF-36 summary scores was 40.6 ± 8.9 and 45.3 ± 9.8, respectively. Participants receiving oxygen therapy (β = -3.20 [95%CI: -5.56; -0.85]), those with a history of femoral osteonecrosis (-3.09 [-4.64; -1.53]), those hospitalized for vaso-occlusive crisis (VOC) or acute chest syndrome (ACS) (-2.58 [-3.93; -1.22]), those with chronic complications (-2.33 [-4.04; -0.62]), female participants (-2.17 [-3.65; -0.69]), those with psychological follow-up (-2.13 [-3.59; -0.67]), older participants (-1.69 [-3.28; -0.09]), and those receiving painkillers (-1.61 [-3.16; -0.06]) reported worse PCS score. By contrast, those who had completed secondary or high school (4.36 [2.41; 6.31]) and those with stable financial situation (2.85 [0.94, 4.76]) reported better PCS scores. Worse MCS scores were reported among participants with psychological follow-up (-2.54 [-4.28; -0.80]) and those hospitalized for VOC/ACS in the last 12 months (-2.38 [-3.99; -0.77]), while those who had relatives' support (5.27 [1.92; 8.62]) and those with stable financial situation (4.95 [2.65; 7.26]) reported better MCS scores.

Conclusion

Adults with major SCD reported poor physical and mental HRQoL scores. Hospitalization for VOC/ACS, chronic complications, use of painkillers, perceived financial situation, and support from relatives are important predictors of HRQoL in SCD patients. Interventions to improve HRQoL outcomes SCD should be considered.

Autologous gene therapy for hemoglobinopathies: From bench to patient's bedside

In recent years, a growing number of clinical trials have been initiated to evaluate gene therapy approaches for the treatment of patients with transfusion-dependent β-thalassemia and sickle cell disease (SCD). Therapeutic modalities being assessed in these trials utilize different molecular techniques, including lentiviral vectors to add functional copies of the gene encoding the hemoglobin β subunit in defective cells and CRISPR-Cas9, transcription activator-like effector protein nuclease, and zinc finger nuclease gene editing strategies to either directly address the underlying genetic cause of disease or induce fetal hemoglobin production by gene disruption. Here, we review the mechanisms of action of these various gene addition and gene editing approaches and describe the status of clinical trials designed to evaluate the potentially for these approaches to provide one-time functional cures to patients with transfusion-dependent β-thalassemia and SCD.

New Horizons in Emergency Department Management of Pediatric Sickle Cell Disease

Sickle cell disease (SCD) is an important topic for emergency medicine audiences because complications of the disease account for a large proportion of hematologic emergencies that are seen in the emergency department each year. Early recognition and aggressive management of emergency complications of SCD can help to reduce the morbidity and mortality associated with this disease. While the treatment recommendations for some complications of SCD are based on expert opinion, there has been advancement in the understanding of the pathogenesis of the disease and evidence regarding the treatment options available for managing acute complications. This continuing medical education article will provide a summary of the clinical manifestation and management of the most common acute complications of SCD: infection, vaso-occlusive episode, acute chest syndrome, splenic sequestration, stroke, and priapism.

New Horizons in Emergency Department Management of Pediatric Sickle Cell Disease

ABSTRACT

Sickle cell disease (SCD) is an important topic for emergency medicine audiences because complications of the disease account for a large proportion of hematologic emergencies that are seen in the emergency department each year. Early recognition and aggressive management of emergency complications of SCD can help to reduce the morbidity and mortality associated with this disease. Although the treatment recommendations for some complications of SCD are based on expert opinion, there has been advancement in the understanding of the pathogenesis of the disease and evidence regarding the treatment options available for managing acute complications. This continuing medical education article will provide a summary of the clinical manifestation and management of the most common acute complications of SCD: infection, vaso-occlusive episode, acute chest syndrome, splenic sequestration, stroke, and priapism.

Mesenchymal Stem Cell Therapy for Bone Repair of Human Hip Osteonecrosis with Bilateral Match-Control Evaluation: Impact of Tissue Source, Cell Count, Disease Stage, and Volume Size on 908 Hips

We investigated the impact of mesenchymal stem cell (MSC) therapy on treating bilateral human hip osteonecrosis, analyzing 908 cases. This study assesses factors such as tissue source and cell count, comparing core decompression with various cell therapies. This research emphasizes bone repair according to pre-treatment conditions and the specificities of cell therapy in osteonecrosis repair, indicating a potential for improved bone repair strategies in hips without femoral head collapse. This study utilized a single-center retrospective analysis to investigate the efficacy of cellular approaches in the bone repair of osteonecrosis. It examined the impact on bone repair of tissue source (autologous bone marrow concentrate, allogeneic expanded, autologous expanded), cell quantity (from none in core decompression alone to millions in cell therapy), and osteonecrosis stage and volume. Excluding hips with femoral head collapse, it focused on patients who had bilateral hip osteonecrosis, both pre-operative and post-operative MRIs, and a follow-up of over five years. The analysis divided these patients into seven groups based on match control treatment variations in bilateral hip osteonecrosis, primarily investigating the outcomes between core decompression, washing effect, and different tissue sources of MSCs. Younger patients (<30 years) demonstrated significantly better repair volumes, particularly in stage II lesions, than older counterparts. Additionally, bone repair volume increased with the number of implanted MSCs up to 1,000,000, beyond which no additional benefits were observed. No significant difference was observed in repair outcomes between different sources of MSCs (BMAC, allogenic, or expanded cells). The study also highlighted that a 'washing effect' was beneficial, particularly for larger-volume osteonecrosis when combined with core decompression. Partial bone repair was the more frequent event observed, while total bone repair of osteonecrosis was rare. The volume and stage of osteonecrosis, alongside the number of injected cells, significantly affected treatment outcomes. In summary, this study provides comprehensive insights into the effectiveness and variables influencing the use of mesenchymal stem cells in treating human hip osteonecrosis. It emphasizes the potential of cell therapy while acknowledging the complexity and variability of results based on factors such as age, cell count, and disease stage.

Impact of hospitalized vaso-occlusive crises in the previous calendar year on mortality and complications in adults with sickle cell disease: a French population-based study

Background

Historically, sickle cell disease (SCD) patients experiencing frequent hospitalized vaso-occlusive crises (HVOC) have been associated with increased mortality, yet recent data reflecting the widespread use of hydroxyurea and advancements in disease management remain limited. Our study aims to assess the association between HVOC and mortality or severe complications in patients with SCD in this new treatment landscape.

Methods

This was a retrospective observational cohort study using the French national health data system. Between 01-01-2012 and 12-31-2018, all SCD patients ≥16 years old (ICD-10 codes D57.0-2) were included and followed until 12-31-2018. HVOC was defined as a hospitalization of ≥1 night with primary diagnosis of SCD with crisis, following an emergency room visit. The association between HVOC and severe complications was assessed with a Cox proportional hazards model.

Findings

In total, 8018 patients (56.6% females; 4538/8018) were included. The 2018 SCD standardized one-year period prevalence was 17.9 cases/100,000 person-years [17.4; 18.3]. The mean rate was 0.84 (1.88) HVOC/person-year. In 2018, 70% (5323/7605), 22% (1671/7605), and 8% (611/7605) of patients experienced 0, 1-2, or 3+ HVOCs, respectively. The median survival time between HVOCs was 415 days [386; 439]. Overall, 312 patients died (3.9%) with a mean age of 49.8 (19.4). Compared to patients without HVOC, the hazard ratios of death in patients with 1-2 or 3+ HVOCs the year prior to death were 1.67 [1.21; 2.30] and 3.70 [2.30; 5.93], respectively. Incidence of acute chest syndrome, pulmonary embolism, osteonecrosis, and sepsis increased with the HVOCs category, but not stroke. In 2018, 29.5% (180/611) of patients with 3+ HVOCs did not take hydroxyurea.

Interpretation

Patients must be closely monitored during their hospitalizations to intensify treatment and check treatment compliance. Innovative therapies are also required.

Funding

The study was funded by Novartis.

Prevalence and predictors of iron deficiency anaemia among children with sickle cell disease in Dodoma, Tanzania: a cross-sectional study

BACKGROUND

Patients with sickle cell disease (SCD) are prone to iron profile derangements. This study aimed to determine the prevalence of iron deficiency anaemia (IDA) and their predictors among children with SCD aged between 6 months and 14 years. Assessment of the prevalence of IDA and its predictors helps to understand ways of alleviating the magnitude of the problem so as to prevent possible complications such as shortness of breath and chest pain.

METHODS

This was a cross-sectional analytical hospital-based study which included 174 patients with SCD attending SCD clinics at St. Gema hospital and Dodoma regional referral hospital in Dodoma city from October 2020 to March 2021. The cut-off points for detection of IDA was serum ferritin level < 30 µg/L and low mean corpuscular volume (MCV) for age. Data were analyzed using SPSS software version 25.0. Multivariate logistic regression analysis was used to determine the predictors of IDA. P-value less than 0.05 was considered significant.

RESULTS

The prevalence of IDA in this study was (16.1%, n = 28). Family income of less than 70,000/= TZS/month (AOR = 2.2, 95% CI = 1.07-2.49, p = 0.023), being transfused with blood less than 3 times from the time of being diagnosed with SCD (AOR = 5.5, 95% CI = 1.03-8.91, p = 0.046), and eating red meat at least once per month (AOR = 3.60, 95% CI = 1.37-9.46, p = 0.010) remained the independent predictors of IDA in multivariate regression analysis.

CONCLUSION

The findings of this study have shown that, support of families with children suffering from SCD in terms of financial support for improving medical services including optimal blood transfusion and affordability of diet which is rich in iron such as red meat is imperative.

Factors associated with adverse outcome among children with sickle cell disease admitted to the pediatric intensive care unit: an observational cohort

BACKGROUND

Sickle cell disease (SCD) is one of the most frequent inherited diseases in the world. Over the last decades, in high-income countries, an important decrease in mortality have been observed due to the improvement of care. However, children with SCD can become critically ill and require admission in Pediatric Intensive Care Units (PICU). The purpose of this study was to describe the epidemiology of children with SCD admitted to PICU for acute crisis and to identify factors associated with adverse outcome (AO).

METHODS

We conducted a retrospective study in a Tertiary Hospital in France including all consecutive children with SCD admitted to PICU between January 1st, 2009 and December 31, 2019. We collected baseline patient's characteristics, clinical and biological data as well as treatments and life sustaining therapies used in the PICU. Patients were defined as experiencing AO in case of death during stay and/or need for invasive mechanical ventilation (MV) and/or for non-invasive ventilation (NIV) for more than 3 days and/or need for vasopressors and/or need for renal replacement therapy.

RESULTS

We included 579 admissions in 395 patients, mainly of SS genotype (90%) with a median age of 9.2 years [5.5-13.4] and a median baseline hemoglobin of 8.0 g/dl (7.5-8.8). The two main reasons for admission were acute chest syndrome (ACS) (n = 331, 57%) and vaso-occlusive crisis refractory to first line therapy (n = 99, 17%). Half of patients required NIV and 47 (8%) required MV. The overall length of stay was 3 days [1-4] and seven (1%) patients died during PICU stay.There was a total of 113 (20%) admissions with AO and on multivariable analysis, baseline hemoglobin < 8 g/dL, history of bronchial obstruction and admission for ACS were associated with AO. There was no difference in the proportion of hydroxyurea treatment or exchange transfusion program between patients with AO and the other patients.

CONCLUSIONS

Baseline hemoglobin < 8 g/dL, history of bronchial obstruction and admission for ACS were the strongest risk factors for severe evolution in SCD children admitted to PICU. These factors could be taken into consideration when choosing the adequate therapeutic options.

Models of care for sickle cell disease in low-income and lower-middle-income countries: a scoping review

Sickle cell disease has a growing global burden falling primarily on low-income countries (LICs) and lower-middle-income countries (LMICs) where comprehensive care is often insufficient, particularly in rural areas. Integrated care models might be beneficial for improving access to care in areas with human resource and infrastructure constraints. As part of the Centre for Integration Science's ongoing efforts to define, systematise, and implement integrated care delivery models for non-communicable diseases (NCDs), this Review explores models of care for sickle cell disease in LICs and LMICs. We identified 99 models from 136 studies, primarily done in tertiary, urban facilities in LMICs. Except for two models of integrated care for concurrent treatment of other conditions, sickle cell disease care was mostly provided in specialised clinics, which are low in number and accessibility. The scarcity of published evidence of models of care for sickle cell disease and integrated care in rural settings of LICs and LMICs shows a need to implement more integrated models to improve access, particularly in rural areas. PEN-Plus, a model of decentralised, integrated care for severe chronic non-communicable diseases, provides an approach to service integration that could fill gaps in access to comprehensive sickle cell disease care in LICs and LMICs.

Sickle Cell Disease in an Older Adult Population: A Retrospective Review of Health Care Resource Utilization

Sickle cell disease (SCD) has a history of health inequity, as patients with SCD are primarily Black and often marginalized from the health care system. Although recent health care and treatment advancements have prolonged life expectancy, it may be insufficient to support the complex needs of the growing population of older adults with SCD. This retrospective study used a cohort (N = 812) of Medicare Advantage beneficiaries 45 years and older (ages: 45-54, 55-64, 65-74, 75-89) with SCD to identify associations of SCD-related complications and comorbidities with emergency department (ED) visits, potentially avoidable ED visits, all-cause hospitalization, and potentially avoidable hospitalizations, 2018-2020. The 75-89 age group had lower odds of an ED visit (OR 0.56; 95% CI 0.32-1.00), 65-74 age group had lower odds of an ED visit (OR 0.49; 95% CI 0.31-0.78) and hospitalization (OR 0.50; 95% CI 0.31-0.79), compared with the 45-54 age group. Acute chest syndrome was associated with increased odds of an ED visit (OR 2.02; 95% CI 1.10-3.71), avoidable ED visit (OR 1.87; 95% CI 1.14-3.06), and hospitalization (OR 3.61; 95% CI 2.06-6.31). Pain was associated with increased odds of an ED visit (OR 2.64; 95% CI 1.85-3.76), an avoidable ED visit (OR 3.08; 95% CI 1.90-4.98), hospitalization (OR 1.51; 95% CI 1.02-2.24), and avoidable hospitalization (OR 6.42; 95% CI 1.74-23.74). Older adults with SCD have been living with SCD for decades, often while managing pain crises and complications associated increased incidence of an ED visit and hospitalization. The characteristics and needs of this population must continue to be examined to increase preventative care and reduce costly emergent health care resource utilization.

Proliferative Sickle Cell Retinopathy: A Patient and a Physician's Perspective on Quality of Life and Quality of Eye Care

The impact of visual impairment in the context of sickle cell disease is poorly understood. Despite the significant advancements over the past three decades in retinal imaging and in the understanding of molecular mechanisms that drive retinal neovascularization, there has been little improvement in the management of proliferative sickle cell retinopathy. This article is co-authored by a patient impacted by proliferative sickle cell retinopathy. She highlights her personal experience of sight loss from proliferative sickle cell retinopathy and the impact on her daily life and mental health. Subsequent to diagnosis and management of proliferative sickle cell retinopathy, she continues to live with irreversible sight loss and provides crucial insight from a patient's perspective into the broad lack of high-quality educational materials online and lack of understanding of the disease within the clinical community. This article aims to provide a strong narrative to emphasize the need for further qualitative and quantitative research in this area, to bring about the holistic step-change required to improve visual outcomes and eyecare for people with sickle cell disease.

Real-world evidence of the burden of sickle cell disease: a 5-year longitudinal study at a Brazilian reference center

INTRODUCTION

Sickle cell disease (SCD) is an inherited and multisystem blood disorder characterized by hemolytic anemia, vaso-occlusive crises (VOCs), progressive multiorgan damage and increased mortality. In Brazil, it is one of the most common monogenic diseases afflicting 60,000 to 100,000 individuals, however, there are sparse epidemiological data, as well as information on the utilization of public healthcare resources.

METHOD

This was a 5-year (2016 - 2020) retrospective study conducted at one Brazilian reference center on SCD - Santa Casa de Sao Paulo, in Sao Paulo, Brazil.

RESULTS

Among a total of 100 eligible adult patients, the median age was 31.0 years old, 84% of the patients were aged between 18 and 45 years old; 59% were women and 91% presented the genotype HbSS. The number of hematologist and non-hematologist visits at the outpatient unit were 2,198 and 1,436, respectively. The number of hospital ER visits was 758, of which 51% required 864 days of hospitalization. The main cause for seeking hospital medical care was the VOCs. The numbers and ratios of VOCs were: 1 to 10 VOCs, 64%; 11 to 20, 15%, and; 21 or more, 1%. There was a statistically significant difference between the number of VOCs and hospitalizations, as well as infection.

CONCLUSION

Results indicate the burden of SCD on Brazilian patients' daily lives, the impact of VOCs on public healthcare resources, the importance of having a national surveillance program to improve resource utilization and clinical outcomes of patients with SCD and the urgent need for the revitalizing of the current national comprehensive SCD care programs.

Long-Term Ovarian Function Assessment After Haematopoietic Stem Cell Transplantation in Female Sickle Cell Anaemia Survivors

BACKGROUND

Haematopoietic stem cell transplantation (HSCT) is a potentially curative treatment for sickle cell anaemia (SCA). While HSCT offers the possibility of disease remission, it can also lead to long-term complications, including gonadal dysfunction and premature menopause.

METHODS

We conducted a retrospective cohort study of female survivors who had hydroxyurea therapy and those who underwent post-HSCT follow-up for SCA at a teaching hospital in Lagos, Nigeria, between January 2019 and December 2022. Participants were eligible if they were at least five years post-HSCT or hydroxyurea treatment and had available serum samples for markers of ovarian function measurement. Demographic and clinical data were collected from the hospital register and patients' medical records. Serum levels of oestradiol, luteinizing hormone (LH), follicle-stimulating hormone (FSH), and anti-Müllerian hormone (AMH) were measured using the Abbott Architect i1000SR chemiluminescent immunoassay analyzer (Abbott Diagnostics, Abbott Park, IL). Descriptive statistics and inferential analyses were used to assess the relationship between markers of ovarian function (FSH and AMH) and clinical parameters.

RESULTS

There were statistically significant differences in the median serum levels of all the assessed endocrine hormones between the HSCT and non-HSCT (hydroxyurea) groups of SCA survivors. Up to 82.6% of the SCA survivors experienced ovarian dysfunction after HSCT treatment. Impaired ovarian function in SCA survivors was associated with a longer median follow-up duration than in SCA survivors who had normal ovarian function (12.0 vs. 7.5 years, p = 0.048). There were higher odds of impaired ovarian function in the SCA survivors who had myeloablative regimens than in those who had reduced intensity conditioning regimens (94.1% vs. 50.0%, p = 0.040).

CONCLUSION

Our study highlights the significant impact of HSCT on long-term ovarian function in female SCA survivors. However, further prospective studies with larger sample sizes and longer follow-up periods are required to confirm our findings and elucidate the factors influencing ovarian function in SCA survivors of HSCT. In addition, studies are also needed to further elucidate the optimal transplant protocols and fertility preservation strategies to minimize gonadal toxicity and preserve reproductive potential in female SCA patients undergoing HSCT.

Endline assessment of knowledge about sickle cell disease among the tribal community of Chhotaudepur district of Gujarat

Sickle cell disease (SCD) is a significant public health concern in India, with one of the highest disability burdens worldwide. For the success of the disease prevention and control program that aims to reduce prevalence through health promotion and screening, the public's prior knowledge of the disease is important. Hence, this study was conducted to assess baseline knowledge of the disease and effects of health education and community mobilization program in the SCD endemic tribal community of Gujarat. This quasi-experimental study was conducted in three phases at Chhotaudepur district of Gujarat, India. Knowledge of the community was assessed through the administration of pretested quantitative questionnaire in 1646 and 1631 individuals respectively during formative and evaluation phases. Differences between the proportions of two phases were statistically assessed by chi-square tests. Despite 75.3% of respondents having heard of SCD before, only 20% could perceive the correct cause. It was improved by 42% post-intervention. During the evaluation, 83% respondents recognized the most common symptom of extreme pain, whereas 86.8% identified the correct diagnostic method. Seventy-seven percent respondents reported modern medicine as a treatment for SCD at endline. Knowledge and awareness about SCD were found inadequate in the community. However, health education intervention strategies effectively improved knowledge related to the disease and its causes, diagnosis, and treatment. Hence, urgent action is required to incorporate community mobilization and awareness generation strategies to mitigate the disease burden.

Early Cholecystectomy in Patients with Sickle Cell Disease with Uncomplicated Cholelithiasis Is Associated with Better Outcomes

BACKGROUND

Up to 85% of patients with sickle cell disease (SCD) will develop gallstones by their third decade. Cholecystectomy is the most commonly performed procedure in these patients. Cholecystectomy is recommended for patients with SCD with symptomatic cholelithiasis and leads to lower morbidity. No contemporary large studies have evaluated this recommendation or associated clinical outcomes. This study evaluates clinical outcomes after cholecystectomy in patients with SCD and cholelithiasis with specific advanced clinical presentations.

STUDY DESIGN

The Nationwide Inpatient Sample was queried for patients with SCD and gallbladder disease between 2006 and 2015. Patients were divided into groups based on their disease presentation, including uncomplicated cholelithiasis, acute and chronic cholecystitis, and gallstone pancreatitis. Clinical outcomes associated with disease presentation were analyzed. Statistical analysis was performed using the Student's t -test, chi-square test, ANOVA, and logistic regression.

RESULTS

There were 6,662 patients with SCD who presented with cholelithiasis. Median age was 20 (interquartile range 16 to 34) years and 54% were female patients. Cholecystectomy was performed in 1,779 patients with SCD with the most common indication being chronic cholecystitis (44%), followed by uncomplicated cholelithiasis (27%), acute cholecystitis (21%), and choledocholithiasis or gallstone pancreatitis (8%). On multivariable regression, advanced clinical presentation was the strongest predictor of perioperative vaso-occlusive crisis, which was the most common complication. Patients undergoing cholecystectomy for uncomplicated cholelithiasis were at lower risk than those with acute cholecystitis (odds ratio [OR] 2.37; 95% CI 1.64 to 3.41), chronic cholecystitis (OR 1.74; 95% CI 1.26 to 2.4), and choledocholithiasis or gallstone pancreatitis (OR 2.24; 95% CI 1.41 to 3.57).

CONCLUSIONS

Seventy-three percent of patients with SCD have advanced clinical presentation at the time of their cholecystectomy. After cholecystectomy, perioperative vaso-occlusive events were significantly increased in patients with advanced clinical presentation. These data support screening abdominal ultrasounds and early cholecystectomy for cholelithiasis in patients with SCD.

Dental Caries in Children with Sickle Cell Disease and Its Association with the Use of Hydroxyurea and Penicillin Prophylaxis in Dar Es Salaam

Purpose

This comparative study sets out to report dental caries status among individuals with Sickle Cell Disease (HbSS) against those with sickle cell trait (HbSA) and those without the disease (HbAA) as controls. The study further assessed the impact of penicillin chemoprophylaxis and hydroxyurea use on dental caries among Sickle Cell Disease participants.

Methods

This was a comparative cross-sectional study in which 93 children aged 30 to 60 months were recruited. There were 60 participating children who had SCD (HbSS), 17 with SCD trait (HbAS) and 16 were without SCD or SC trait (HbAA). A questionnaire was used to record sociodemographic details including mean age in months and sex and on haemoglobin genotype for all the participants. Specifically, for the participants with HbSS, information on their whether they are taking hydroxyurea (HU), and penicillin chemoprophylaxis was recorded. To assess the prevalence of dental caries, clinical examination of all primary maxillary and mandibular teeth to determine the presence or absence of dental caries lesions was also recorded.

Results

A total of 1197 teeth from 93 children were examined, whereby, 45 (2.4%) of them had dental caries. The participating children with HbAA genotype (6.6%, N=21) had more dental caries than their HbSS counterparts (2.0%, N=24), while none of the participants with HbAS exhibited dental caries. Among the participants with HbSS, males and those who use HU were 3.79 and 3.07 times more likely to have dental caries than their counterparts, female and non-users of HU, respectively.

Conclusion

Dental caries was observed to be low among participants with HbSS when compared to those with HbAA. More research utilizing more robust methodologies is recommended.

Gut Microbiota: Potential Therapeutic Target for Sickle Cell Disease Pain and Complications

Aim

Sickle cell disease has witnessed a 41.4% surge from 2000 to 2021, significantly affecting morbidity and mortality rates, particularly in children from regions with elevated under-5 mortality rates. Gut microbiota dysbiosis is increasingly recognised in SCD, exacerbating complications, particularly chronic pain, marked by significant alterations of proinflammatory bacteria abundance. This review explores the therapeutic potential of Akkermansia muciniphila and Roseburia spp. in alleviating SCD-related complications, emphasising their roles in maintaining gut barrier integrity, reducing inflammation, and modulating immune responses.

Method

A literature search up to November 2023 using PubMed, MEDLINE, and Google Scholar databases explored SCD pathophysiology, gut microbiota composition, Akkermansia muciniphila and Roseburia spp. abundance, pain and gut dysbiosis in SCD, and butyrate therapy.

Result

A. muciniphila and Roseburia spp. supplementation shows promise in alleviating chronic pain by addressing gut dysbiosis, offering new avenues for sustainable SCD management. This approach holds the potential for reducing reliance on reactive treatments and improving overall quality of life. This research underscores the pivotal role of the gut microbiome in SCD, advocating for personalised treatment approaches.

Conclusion

Further exploration and clinical trials are needed to harness the full potential of these gut bacteria for individuals affected by this challenging condition.

Recent developments in the use of pyruvate kinase activators as a new approach for treating sickle cell disease

ABSTRACT

Pyruvate kinase (PK) is a key enzyme in glycolysis, the sole source of adenosine triphosphate, which is essential for all energy-dependent activities of red blood cells. Activating PK shows great potential for treating a broad range of hemolytic anemias beyond PK deficiency, because they also enhance activity of wild-type PK. Motivated by observations of sickle-cell complications in sickle-trait individuals with concomitant PK deficiency, activating endogenous PK offers a novel and promising approach for treating patients with sickle-cell disease.

Self-management needs, strategies and support for sickle cell disease in developing countries: a scoping review protocol

INTRODUCTION

Sickle cell disease (SCD) poses a significant global health burden, particularly affecting individuals in developing countries with constrained healthcare resources. While research on self-management in the context of SCD is emerging, it has predominantly focused on primary studies, and there is a notable dearth of evidence synthesis on SCD self-management in developing countries. This scoping review aims to identify and map self-management needs of individuals living with SCD, the strategies they employed to meet those needs, and the support systems available to them.

METHODS AND ANALYSIS

The review will be conducted following the Arksey and O'Malley's (2005) 29 framework to comprehensively examine the landscape of SCD self-management research. Searches will be performed in PubMed, Scopus, Embase and Dimensions AI, with additional searches in other databases and grey literature. Indexed literature published in English from inception to January 2024 will be included. Reference list from included studies will also be searched manually. Two teams will be constituted to independently screen titles, abstracts and full text against the eligible criteria. Data will be extracted from included studies onto a customised data extraction form.

ETHICS AND DISSEMINATION

Ethical approval is not required for this review due to the fact that it synthesises information from available publications. The findings will be disseminated through publication in a peer-reviewed journal. Also, the findings will possibly be presented at relevant international and national conferences. This protocol has already been registered with the Open Science Framework. The study characteristics such as design and setting will be descriptively analysed and presented as graphs, tables and figures. Thematic analysis will also be conducted based on the study objectives and presented as a narrative summary.

Acute kidney injury is more common in hospitalised children with sickle cell anaemia in Africa

AIM

To document the prevalence, severity, hospital outcome and factors associated with acute kidney injury (AKI) in hospitalised children with sickle cell anaemia (SCA).

METHODS

In this prospective observational study involving children aged 0.5-17 years with SCA requiring hospitalisation, we used serum creatinine level at 0 and 48 h of hospitalisation to determine the presence of AKI.

RESULTS

The study involved 155 children with SCA aged 0.5-17 years with a median (interquartile range) age of 7.8 (4.3-11.0) years. Acute kidney injury occurred in 27 (17.4%) children with 33.3% reaching stage 3. Hepatomegaly (81.5% vs. 55.4%; p = 0.015), splenomegaly (33.3% vs. 10.9%; p = 0.003), dipstick proteinuria (22.2% vs. 5.4%; p = 0.004), and hematuria (29.6% vs. 3.1%; p = <0.001) were more common in those with AKI. In contrast, children with AKI had lower haematocrit (16.9% vs. 22.2%; p = <0.001) and serum bicarbonate (16.7 vs. 19.1 mmoL/L; p = 0.010) compared with those without AKI. Those with AKI had longer hospital stay (median [interquartile range]: 7 [4-12] days vs. 4 [3-6] days; p = 0.008).

CONCLUSION

AKI is common among hospitalised children with AKI and is associated with longer hospital stay.

Unveiling mortality risk factors in paediatric sickle cell disease patients during acute crises in the Democratic Republic of the Congo

Sickle cell disease (SCD) is a significant health burden in the Democratic Republic of the Congo (DRC). This study aims to identify predictive factors of mortality in SCD children admitted to emergency care in Lubumbashi, DRC. We performed a non-interventional cohort follow-up on SCD patients aged 0 to 16 admitted for a "true emergency". Demographic, clinical, and biological data were collected. Univariate and multivariate logistic regression analyses were performed to identify significant risk factors associated with mortality. Among the 121 patients included, 24 died during the follow-up period. Univariate regression revealed age, Mikobi score, referral origin, stroke, and severe infection as significant risk factors. Multivariate analyses identified Hb, WBC, SR, and LDH as predictive factors of mortality. Notably, patients aged 12 to 16 years faced a higher risk, shifting the age of mortality from early to late childhood and adolescence. This study provides valuable insights into mortality risk factors for paediatric SCD patients during acute crises. Early diagnosis, regular follow-up, and therapeutic education are essential to improve patient outcomes and survival rates. These findings contribute to better disease management and targeted interventions, aiming to reduce mortality associated with SCD.

Chronic humeral osteomyelitis in an adult with sickle-cell disease

INTRODUCTION AND IMPORTANCE

The rising incidence of sickle-cell disease in European countries has led to an increase in associated complications. Osteomyelitis, a rare complication in non-traumatic adult cases, poses diagnostic challenges and presents treatment difficulties due to limited cases and studies.

CASE PRESENTATION

A 23-year-old woman diagnosed with sickle-cell disease presented with a six-day fever and painful swelling in the left upper extremity persisting for a fortnight. She had no history of trauma but had experienced a previous episode of bacteremia due to Salmonella, four years prior. Magnetic resonance imaging revealed an intramedullary bone injury with cortical rupture extending into soft tissues, forming a collection that raised clinical suspicion of osteomyelitis, despite negative blood and aspirate cultures. Empiric antibiotic therapy was initiated, followed by surgical debridement of infected tissues. The resulting dead space was filled with antibiotic-coated calcium phosphate beads and tissue grafting. Anatomopathological studies confirmed findings consistent with chronic osteomyelitis. Stabilization of the arm was achieved with an orthopedic brace, and antibiotic administration continued for 6 weeks post-surgery. The injury consolidated 4 months after treatment, and nearly two years later she has not suffered a recurrence.

CLINICAL DISCUSSION

The scarcity of literature implies the absence of clinical guidelines for treating osteomyelitis in these patients. Empirical antibiotic therapy combined with surgery when there are abscesses that need debridement can be an effective approach.

CONCLUSION

Humeral osteomyelitis in sickle-cell disease patients can be effectively managed using a pharmaco-surgical strategy, but it should be tailored to the patient's needs.

Hydroxyurea for secondary stroke prevention in children with sickle cell anaemia: a systematic review of clinical evidence and outcomes

Background

Stroke remains one of the leading complications of sickle cell anaemia (SCA) in children. Traditionally, SCA treatment focused on symptom relief. However, the high incidence of strokes in children has prompted a reevaluation of treatment, particularly hydroxyurea, for secondary stroke prevention. This study assesses hydroxyurea's effectiveness and safety in preventing secondary strokes in paediatric SCA patients.

Methods

This systematic review followed a pre-defined protocol registered with PROSPERO. Comprehensive searches were conducted across PubMed, Embase, Scopus, MEDLINE, Google Scholar, and the Cochrane Library up to August 2023. Studies were included involving paediatric SCA patients at risk of secondary stroke, assessing hydroxyurea as the primary intervention.

Results

A total of six studies meeting inclusion criteria were included. The effectiveness of hydroxyurea in preventing secondary strokes, with variable responses reported across studies. Adverse effects, including mild neutropenia, are associated with hydroxyurea treatment but with variability in reported toxicity levels.

Conclusion

Hydroxyurea holds promise in preventing recurrent strokes in children with SCA, though its efficacy and safety profiles vary among individuals. Optimal dosages and treatment durations require further investigation, necessitating vigilant monitoring of haematological parameters. Future research should refine dosing strategies, consider individual patient characteristics, assess long-term effects, and explore ancillary benefits beyond stroke prevention.

Multicomponent Strategy Improves Human Papillomavirus Vaccination Rates Among Adolescents with Sickle Cell Disease

OBJECTIVE

To evaluate the effectiveness of a vaccine strategy bundle to increase human papillomavirus (HPV) vaccine initiation and completion in a specialty clinic setting.

STUDY DESIGN

Our Hematology clinic utilized an implementation framework from October 1, 2018, to December 31, 2019, involving nurses, nursing coordinators, and clinicians in administering the HPV vaccination series to our adolescent sickle cell sample of nearly 500 patients. The bundle included education for staff on the need for HPV vaccine administration, provider incentives, vaccines offered to patients in SCD clinics, and verification of patients' charts of vaccine completion.

RESULTS

Following the implementation of the bundle, the cumulative incidence of HPV vaccination initiation and completion improved from 28% to 46% and 7% to 49%, respectively. Both rates remained higher postimplementation as well. HPV vaccination series completion was associated with a decreased distance to the health care facility, lower state deprivation rank, and increased hospitalizations.

CONCLUSION

Our clinic's implementation strategy successfully improved vaccine completion rates among adolescents with sickle cell disease (SCD) while continuing to educate staff, patients, and families on the importance of cancer prevention among people living with SCD.

An update review of new therapies in sickle cell disease: the prospects for drug combinations

INTRODUCTION

Sickle cell disease (SCD) is an inherited disorder characterised by polymerisation of deoxygenated haemoglobin S and microvascular obstruction. The cardinal feature is generalised pain referred to as vaso-occlusive crises (VOC), multi-organ damage and premature death. SCD is the most prevalent inherited life-threatening disorders in the world and over 85% of world's 400,000 annual births occur low-and-middle-income countries. Hydroxyurea remained the only approved disease modifying therapy (1998) until the FDA approved L-glutamine (2017), Crizanlizumab and Voxelotor (2019) and gene therapies (Exa-cel and Lovo-cel, 2023).

AREAS COVERED

Clinical trials performed in the last 10 years (November 2013 - November 2023) were selected for the review. They were divided according to the mechanisms of drug action. The following pubmed central search terms [sickle cell disease] or [sickle cell anaemia] Hydroxycarbamide/ Hydroxyurea, L-Glutamine, Voxelotor, Crizanlizumab, Mitapivat, Etavopivat, gene therapy, haematopoietic stem cell transplantation, and combination therapy.

EXPERT OPINION

We recommend future trials of combination therapies for specific complications such as VOCs, chronic pain and renal impairment as well as personalised medicine approach based on phenotype and patient characteristics. Following recent approval of gene therapy for SCD, the challenge is addressing the role of shared decision-making with families, global access and affordability.

The value-based price of transformative gene therapy for sickle cell disease: a modeling analysis

Sickle cell disease (SCD) is an inherited, progressively debilitating blood disorder. Emerging gene therapies (GTx) may lead to a complete remission, the benefits of such can only be realized if GTx is affordable and accessible in the low-and middle-income countries (LMIC) with the greatest SCD burden. To estimate the health impacts and country-specific value-based prices (VBP) of a future gene therapy for SCD using a cost-utility model framework. We developed a lifetime Markov model to compare the costs and health outcomes of GTx versus standard of care for SCD. We modeled populations in seven LMICs and six high-income countries (HICs) estimating lifetime costs and disability-adjusted life-years (DALYs) in comparison to estimates of a country's cost-effectiveness threshold. Each country's unique VBP for GTx was calculated via threshold analysis. Relative to SOC treatment alone, we found that hypothetical GTx reduced the number of people symptomatic with SCD over time leading to fewer DALYs. Across countries, VBPs ranged from $3.6 million (US) to $700 (Uganda). Our results indicate a wide range of GTx prices are required if it is to be made widely available and may inform burden and affordability for 'target product profiles' of GTx in SCD.

Awareness of sickle cell disease among nursing undergraduates in Farasan: Its interference with malaria

Aim

The present study was conducted to generate data on awareness and incidence of sickle cell disease (SCD) and also to adduce the widespread myths peddled about SCD.

Materials and Methods

Students studying in the Department of Nursing were recruited. A pretested, self-administered sickle cell assessment questionnaire was distributed electronically through WhatsApp group to collect necessary data. Participants were screened for malaria by thin blood smear analyses, and their hemoglobin (Hb) contents (g/dL) were determined by Sahli's haemoglobinometer. Statistical analyses were done using Origin (version 8.1, USA). A reliability study was performed for the validity of questionnaire data.

Results

Study participants had significantly high awareness regarding SCDs (89.9%, P < 0.001). Most participants (96.3%) were aware about government policy regarding premarital screening for genetic disorders and replied that the government has strict health policies backed by equally robust laboratory diagnostics. Moreover, none of the participants had SCDs, although their parents had a consanguineous marriage. Thin blood smear analyses of participants did not reveal any cases of Plasmodium falciparum. However, significant percentages (33.1%) were found to be anemic, probably due to their dietary habits and lifestyles, as has been reflected by questionnaire analyses. Furthermore, a very less number of students had knowledge about genetic variations that might occur in malaria-endemic regions after long exposure to offer protection from malaria. Knowledge about management practices was also lacking among study participants (29%).

Conclusion

This research points to the necessity that the nursing study plan should focus on providing specific training on management skills and preventive measures for SCDs, which is of paramount importance.

Sickle Cell Disease Update: New Treatments and Challenging Nutritional Interventions

Sickle cell disease (SCD), a distinctive and often overlooked illness in the 21st century, is a congenital blood disorder characterized by considerable phenotypic diversity. It comprises a group of disorders, with sickle cell anemia (SCA) being the most prevalent and serious genotype. Although there have been some systematic reviews of global data, worldwide statistics regarding SCD prevalence, morbidity, and mortality remain scarce. In developed countries with a lower number of sickle cell patients, cutting-edge technologies have led to the development of new treatments. However, in developing settings where sickle cell disease (SCD) is more prevalent, medical management, rather than a cure, still relies on the use of hydroxyurea, blood transfusions, and analgesics. This is a disease that affects red blood cells, consequently affecting most organs in diverse manners. We discuss its etiology and the advent of new technologies, but the aim of this study is to understand the various types of nutrition-related studies involving individuals suffering from SCD, particularly in Africa. The interplay of the environment, food, gut microbiota, along with their respective genomes collectively known as the gut microbiome, and host metabolism is responsible for mediating host metabolic phenotypes and modulating gut microbiota. In addition, it serves the purpose of providing essential nutrients. Moreover, it engages in direct interactions with host homeostasis and the immune system, as well as indirect interactions via metabolites. Nutrition interventions and nutritional care are mechanisms for addressing increased nutrient expenditures and are important aspects of supportive management for patients with SCD. Underprivileged areas in Sub-Saharan Africa should be accompanied by efforts to define and promote of the nutritional aspects of SCD. Their importance is key to maintaining well-being and quality of life, especially because new technologies and products remain limited, while the use of native medicinal plant resources is acknowledged.

Targeted, safe, and efficient gene delivery to human hematopoietic stem and progenitor cells in vivo using the engineered AVID adenovirus vector platform

Targeted delivery and cell-type-specific expression of gene-editing proteins in various cell types in vivo represent major challenges for all viral and non-viral delivery platforms developed to date. Here, we describe the development and analysis of artificial vectors for intravascular delivery (AVIDs), an engineered adenovirus-based gene delivery platform that allows for highly targeted, safe, and efficient gene delivery to human hematopoietic stem and progenitor cells (HSPCs) in vivo after intravenous vector administration. Due to a set of refined structural modifications, intravenous administration of AVIDs did not trigger cytokine storm, hepatotoxicity, or thrombocytopenia. Single intravenous administration of AVIDs to humanized mice, grafted with human CD34+ cells, led to up to 20% transduction of CD34+CD38-CD45RA- HSPC subsets in the bone marrow. Importantly, targeted in vivo transduction of CD34+CD38-CD45RA-CD90-CD49f+ subsets, highly enriched for human hematopoietic stem cells (HSCs), reached up to 19%, which represented a 1,900-fold selectivity in gene delivery to HSC-enriched over lineage-committed CD34-negative cell populations. Because the AVID platform allows for regulated, cell-type-specific expression of gene-editing technologies as well as expression of immunomodulatory proteins to ensure persistence of corrected HSCs in vivo, the HSC-targeted AVID platform may enable development of curative therapies through in vivo gene correction in human HSCs after a single intravenous administration.

Haematopoietic stem cell transplantation in children with sickle cell disease: Still to do?

Sickle cell disease affects the whole body through acute and chronic organ damage and results in significant physical and neurological constraints. The report by Cseh et al. demonstrates in a retrospective multinational study that allogeneic haematopoietic stem cell transplantation from HLA-identical siblings using a contemporary conditioning regimen is safe and effective in more than 96% of patients. Commentary on: Cseh et al. Busulfan-fludarabine- or treosulfan-fludarabine-based conditioning before allogeneic HSCT from matched sibling donors in paediatric patients with sickle cell disease: A study on behalf of the EBMT Paediatric Diseases and Inborn Errors Working Parties. Br J Haematol 2024;204:e1-e5. [Correction added on 23 November 2023, after first online publication: In the preceding sentence, the article title and doi have been updated in this version.].

A social profile of deaths related to sickle cell disease in India: a case for an ethical policy response

India accounts for 14.5 percent of the global SCD newborns, roughly over 42,000 a year, second to sub-Saharan Africa. Despite the availability of cheap diagnostic and treatment options, SCD remains a largely neglected disease within healthcare policy and practice. Epidemiological modeling based on small, often dated, regional studies (largely from sub-Saharan Africa) estimate that between 50 and 90 percent of affected children will/die before the age of 5 years. This premise, coupled with targets of reducing under 5 mortality (SDG 4), privileges public health interventions for screening and prevention of new births, undermining investments in long-term health and social care. This paper presents a retrospective, descriptive analysis of the socio-demographic profile of 447 patients diagnosed with sickle cell or sickle-beta thalassemia, who died following admission at a tertiary care entre in India. We used anonymized hospital records of 3,778 sickle cell patients, admitted in pediatric and adult/medical wards between January 2016 and February 2021. A majority of hospital deaths occurred in the second and third decades of life, following a hospital admission for a week. The overall mortality during 2016-2019 was 14% with little gender difference over time. Contrary to our expectations, the number of hospital deaths did not increase during the first year of the COVID-19 pandemic, between 2020 and 2021. The conclusion highlights the importance of longitudinal, socio-demo-graphic data on deaths as providing important insights for identifying ethical policy interventions focused on improving SCD outcomes over time, reducing inequities in access to care, and preventing what might be considered "excess" deaths.

Application of parametric survival analysis to women patients with breast cancer at Jimma University Medical Center

Public health systems in both industrialized and undeveloped countries continue to struggle with the worldwide problem of breast cancer. In sub-Saharan African countries, notably Ethiopia, it is the form of cancer that strikes women the most commonly. Despite the extreme difficulties, the causes of mortality in Ethiopia have not yet been identified. In addition, little study has been done in this area. Therefore, the major objective of this analysis was to pinpoint the factors that were most responsible for the decreased life expectancy of breast cancer patients at the University of Jimma Medical Center. 552 women who had been treated for breast cancer at Jimma University Medical Center between October 2018 and December 2022 were included in this study, which used a retrospective cohort study design and five-year follow-up data. The most frequent and widely used test for comparing the probability of survival curves between several categorical independent variables was the log-rank test. Next, semi-parametric methods for multivariable analysis using the Cox proportional hazards model were used. Furthermore, a parametric strategy that includes fully parametric survival models better achieves the goal of the analysis. Among covariate, age of patient (ϕ = 254.06; 95% CI (3.95, 7.13), P-value = 0.000), patient live in urban (ϕ = 0.84; 95% CI (-0.35,-0.00), P-value = 0.047), preexisting comorbidity (ϕ = 2.46; 95% CI (0.39, 1.41), P-value = 0.001), overweight women cancer patient (ϕ = 0.05; 95% CI(-4.41,-1.57), P-value = 0.000, positive Axillary Node status cancer patient (ϕ = 0.04; 95% CI(-4.45,-1.88), P-value = 0.000), both surgery and chemotropic baseline treatment patient (ϕ = 0.53; 95% CI(-1.12,-0.16), P-value = 0.009) significantly affected the survival of women breast cancer. Age of breast cancer patient, patient education level, place of residence, marital status, pre-existing comorbidity, axillary node status, estrogen receptor, tumor size, body mass index at diagnosis, stage of cancer, and baseline treatment were found to have a significant effect on time to survive for women with breast cancer at the University of Jimma Medical Center, Oromia region, Ethiopia. However, the covariate histologic grade, number of positive lymph nodes involved, and type of hormone used were insignificant to the survival of breast cancer patients.

The range of haploidentical transplant protocols in sickle cell disease: all haplos are not created equally

The ideal curative therapy for sickle cell disease (SCD) must be applicable across all ages and include individuals with strokes and preexisting heart, lung, and kidney disease. Myeloablative, matched sibling donor hematopoietic stem cell transplant (HCT) for children with SCD has shown excellent outcomes over the past 3 decades but has been restricted due to the limited availability of a human leukocyte antigen-matched sibling donor (10%-15%) and increased treatment-related death in adults with myeloablative conditioning. To overcome these 2 significant barriers to curative therapy in SCD, related haploidentical HCT has become an active area of research. The use of related haploidentical donors (first- and second-degree relatives) increases the donor pool to at least 90% of those eligible across the life span. Importantly, most adults, even with strokes or significant comorbidities, can tolerate the nonmyeloablative conditioning regimen without treatment-related death. Since 2013, at least 3 related haploidentical HCT strategies have emerged as potential curative therapies for SCD: (1) a nonmyeloablative, T-cell replete, bone marrow transplant with thiotepa and posttransplant cyclophosphamide with a goal of complete donor chimerism; (2) a nonmyeloablative, in vivo T-cell depletion, using peripheral blood stem cells (PBSCs) with a goal of stable mixed donor-recipient chimerism; and (3) a myeloablative, ex vivo T-cell depletion using PBSCs and advanced-technology graft manipulation, with a goal of complete donor chimerism. We review the similarities, differences, outcomes, and gaps in knowledge with these 3 haploidentical HCT approaches for SCD.