Doença falciforme: cuidado com pessoas com úlcera da perna nos serviços de atenção à saúde / Sickle cell disease: caring for people with leg ulcers in heal-thcare services / Enfermedad falciforme: cuidado de personas con úlcera de pierna en los servicios de atención a la salud

Objetivo: identificar o local e os cuidados diretos recebidos por pessoas com úlceras da perna por doença falciforme nos serviços de atenção à saúde. Método: estudo transversal, realizado em 11 centros, no período de agosto de 2019 a abril de 2020. Fizeram parte do estudo 72 pessoas com úlcera da perna ativa. O estudo foi aprovado pelo Comitê de Ética em Pesquisa. Resultado: apresentavam anemia falciforme 91,7% dos participantes, com mediana de três anos de existência da úlcera; 77,8% eram redicivantes; 40,3% compravam os insumos; 66,7% trocavam o próprio curativo no domicílio; 52,8% realizavam uma ou mais trocas diárias; 45,8% dos tratamentos foram prescritos pelo médico; 37,5% eram pomada (colagenase ou antibiótico); 89% não utilizavam compressão para o manejo do edema. Conclusão: a maioria dos participantes não estava inserida na Rede de Atenção à Saúde para o tratamento da úlcera, e não recebia assistência sistematizada e nem insumos apropriados.

Objective: to identify the location and direct care received by people with leg ulcers due to sickle cell disease in health care services. Method: a cross-sectional study carried out in 11 centers from August 2019 to April 2020. The study included 72 people with active leg ulcers. The study was approved by the Research Ethics Committee. Results: a total of 91.7% of the participants had sickle cell anemia, with a median of three years of ulcer existence; 77.8% were recurrent; 40.3% bought the supplies; 66.7% changed their own dressings at home; 52.8% did one or more changes a day; 45.8% of the treatments were prescribed by physician; 37.5% were ointments (collagenase or antibiotics); and 89% did not use compression to manage edema. Conclusion: most of the participants were not included in the Health Care Network for ulcer treatment and did not receive systematized care or appropriate supplies.

Objetivo: identificar el lugar y los cuidados directos recibidos por personas con úlceras de pierna por enfermedad falciforme en los servicios de atención a la salud. Método: estudio transversal, realizado en 11 centros, en el período de agosto de 2019 a abril de 2020. Participaron 72 personas con úlcera de pierna activa. El estudio fue aprobado por el Comité de Ética en Investigación. Resultado: presentaban anemia falciforme 91,7% de los participantes, con una mediana de tres años de existencia de la úlcera; 77,8% eran recidivantes; 40,3% compraban los insumos; 66,7% cambiaban su propio vendaje en el domicilio; 52,8% realizaban uno o más cambios diarios; 45,8% de los tratamientos fueron prescritos por el médico; 37,5% eran pomada (colagenasa o antibiótico); y 89% no utilizaban compresión para el manejo del edema. Conclusión: la mayoría de los participantes no estaba integrada en la Red de Atención a la Salud para el tratamiento de la úlcera, y no recibía asistencia sistematizada ni insumos apropiados.

Reproductive Health Assessment and Reports of Fertility Counseling in Pediatric and Adolescent Patients with Sickle Cell Disease After Hematopoietic Cell Transplantation.

Conditioning regimens for hematopoietic cell transplant (HCT) in patients with sickle cell disease (SCD) place patients at risk for reproductive health issues. The purpose of this study was to assess reproductive health and reports of fertility counseling in patients with SCD who received a transplant. This was a secondary analysis of gonadal hormone production, future infertility risk assessment, and parent-proxy/patient reports of fertility counseling in SCD transplant recipients who are currently pubertal and were enrolled in the Atlanta sites of the Sickle Cell Transplant Evaluation of Long-term and Late Effects Registry (STELLAR) between May 2017 and October 2023. Clinical information was abstracted from medical records and reproductive health survey data from the STELLAR database. Descriptive statistics were reported as median (interquartile range [IQR]) or percentages. There were 20 females and 12 males in the study population. Females were median (IQR) 19.6 (9.4) years old and males 20.8 (11.4) years old at the time of the study. Transplants most commonly occurred in the decade 2010 to 2019 at 10.7 (4.8) years old for females and 11.1 (4.1) years old for males. Most participants received bone marrow stem cells (95.0% females, 100.0% males) from matched sibling donors (90.0% females, 100.0% males). Participants received one of seven HCT conditioning regimens with cyclophosphamide equivalent doses ranging from 3388 to 9706 mg/m2. The majority of females (90.0%) had diminished ovarian reserve with low anti-Mullerian hormone levels, and 61.1% had premature ovarian insufficiency with two follicle-stimulating hormone levels (FSH) ≥40 mIU/mL post-HCT. All males had normal testosterone levels, but 63.6% had elevated FSH levels suggestive of impaired spermatogenesis post-HCT. Parent proxies (for patients <18 years old) and patients ≥18 years old completed surveys 9.0 years (5.2) and 7.9 years (9.3) since HCT in females and males respectively. Twenty-five percent of parent proxies and 45% of patients reported that they had not been informed by a healthcare provider of the risk of infertility post-transplant. There are high rates of gonadal dysfunction post-HCT, but many parent proxies and patients do not recall being told of the risk for future infertility. More effective methods of education are warranted to ensure SCD patients and their families clearly understand the risk for reproductive health issues post-HCT.

Ferroptosis as an emerging target in sickle cell disease.

Sickle cell disease (SCD) is an inherited hemoglobin disorder marked by red blood cell sickling, resulting in severe anemia, painful episodes, extensive organ damage, and shortened life expectancy. In SCD, increased iron levels can trigger ferroptosis, a specific type of cell death characterized by reactive oxygen species (ROS) and lipid peroxide accumulation, leading to damage and organ impairments. The intricate interplay between iron, ferroptosis, inflammation, and oxidative stress in SCD underscores the necessity of thoroughly understanding these processes for the development of innovative therapeutic strategies. This review highlights the importance of balancing the complex interactions among various factors and exploitation of the knowledge in developing novel therapeutics for this devastating disease.

Towards genomic medicine: a tailored next-generation sequencing panel for hydroxyurea pharmacogenomics in Tanzania.

BACKGROUND: Pharmacogenomics of hydroxyurea is an important aspect in the management of sickle cell disease (SCD), especially in the era of genomic medicine. Genetic variations in loci associated with HbF induction and drug metabolism are prime targets for hydroxyurea (HU) pharmacogenomics, as these can significantly impact the therapeutic efficacy and safety of HU in SCD patients. METHODS: This study involved designing of a custom panel targeting BCL11A, ARG2, HBB, HBG1, WAC, HBG2, HAO2, MYB, SAR1A, KLF10, CYP2C9, CYP2E1 and NOS1 as potential HU pharmacogenomics targets. These genes were selected based on their known roles in HbF induction and HU metabolism. The panel was designed using the Illumina Design Studio (Illumina, San Diego, CA, USA) and achieved a total coverage of 96% of all genomic targets over a span of 51.6 kilobases (kb). This custom panel was then sequenced using the Illumina MiSeq platform to ensure high coverage and accuracy. RESULTS: We are reporting a successfully designed Illumina (MiSeq) HU pharmacogenomics custom panel encompassing 51.6 kilobases. The designed panel achieved greater than 1000x amplicon coverage which is sufficient for genomic analysis. CONCLUSIONS: This study provides a valuable tool for research in HU pharmacogenomics, especially in Africa where SCD is highly prevalent, and personalized medicine approaches are crucial for improving patient outcomes. The custom-designed Illumina (MiSeq) panel, with its extensive coverage and high sequencing depth, provides a robust platform for studying genetic variations associated with HU response. This panel can contribute to the development of tailored therapeutic strategies, ultimately enhancing the management of SCD through more effective and safer use of hydroxyurea.

Perinatal risk factors and neurocognitive outcomes in children and adolescents with sickle cell disease.

BACKGROUND: The literature on cognitive and academic outcomes for children with sickle cell disease (SCD) who experience perinatal risk factors is limited. We aimed to evaluate if low birthweight (LBW), gestational age, and history of neonatal intensive care unit (NICU) admission were associated with neurocognitive functioning, grade retention, or receipt of early intervention or formal educational support in children with SCD. PROCEDURES: This prospective birth cohort study included 336 participants, ages 8-18, with SCD, who received cognitive testing as part of standard of care and whose caregivers completed behavioral rating scales. Multivariable generalized linear regression models were used to examine associations between perinatal risks and outcome variables, after adjusting for demographic and medical covariates. RESULTS: The prevalence of NICU admission and LBW were 12.03% and 13.50%, respectively. Lower birthweight, earlier gestational age, and NICU admission were associated with worse working memory performance and receipt of early intervention services. Lower birthweight and NICU admission were also associated with slower processing speed. History of NICU admission was associated with caregiver ratings of hyperactivity and emotional dysregulation. The effects of perinatal risk factors on neurocognitive, academic, or educational outcomes were not dependent on SCD genotype. CONCLUSIONS: History of LBW or NICU admission was associated with worse cognitive outcomes and increased use of early intervention services among children with SCD. Early identification of perinatal risk factors will help identify children who will benefit from formal developmental or neuropsychological evaluations to manage the comorbidity of SCD and perinatal risks and facilitate increased intervention.

MRI-confirmed cochlear artery infarct clinically diagnosed in a patient with sickle cell disease: a case report.

PURPOSE: To corroborate the vascular etiology of sudden sensorineural hearing loss (SNHL) utilizing magnetic resonance imaging (MRI). PATIENT: A 24-year-old male with a history of sickle cell disease experienced sudden SNHL and right horizontal nystagmus, without accompanying vertigo. INTERVENTION: Audiometric evaluation revealed left-sided SNHL, predominantly affecting high frequencies. Video head impulse testing demonstrated isolated dysfunction of the left posterior semicircular canal. An urgent brain MRI identified a recent punctiform ischemic stroke in the frontal region. A subsequent MRI, conducted with a 4-hour delay and post-contrast enhancement, highlighted a hyperintense signal within the left cochlear region and the left posterior semicircular canal. CONCLUSION: The investigative results substantiate an infarction in the territory of the cochlear artery, precipitated by a vaso-occlusive event, thereby reinforcing the vascular hypothesis of cochleovestibular artery syndrome. This case underscores the congruence between clinical observations and delayed post-contrast MRI findings.

Safety and efficacy of L-Glutamine in reducing the frequency of acute complications among patients with sickle cell disease: A randomized controlled study.

To evaluate the safety and efficacy of L-glutamine in reducing vaso-occlusive crisis (VOC) and improving cerebral arterial blood flow in children with sickle cell disease (SCD). This is an interventional randomized controlled trial that recruited sixty SCD patients, aged 9.2 ± 3.7 years, who had at least two VOCs during the last 12 months and on a stable dose of hydroxyurea. They were randomly assigned in a 1:1 ratio to receive glutamine (0.3 gm/kg/dose/12h) orally for 24 weeks or the standard of care (SOC). All patients had VOCs in the last year > 3, those on glutamine had a higher number of VOCs and hospitalization for VOC in the last year. There was a decreasing trend in the number, severity, and hospitalization of VOC and a significantly lower cumulative number of VOCs and hospitalizations in the glutamine group than in SOC (p = 0.008, p < 0.001 respectively). Time-averaged mean maximum velocity for the glutamine group had a marginal increase in both middle cerebral arteries, all values remained normal within a normal range, and in both internal carotid arteries, values increased from abnormally low to normal ranges at week 24. Glutamine reduced the number of VOCs and severity and may have a potentially favorable impact on the cerebral arterial flow velocities.

Pain sensitisation in patients with sickle cell disease: A preliminary study.

BACKGROUND: Responses to experimental pain have suggested central and peripheral sensitisation in adult patients with sickle cell disease (SCD). Recent studies have proposed an algometry-derived dynamic measure of pain sensitisation, slowly repeated evoked pain (SREP), which is useful in the discrimination of painful conditions related to central sensitisation. Pain and fatigue are two symptoms that affect the general functioning of patients with SCD most significantly, however, research about experimental dynamic pain measures and their relation to the main symptoms of SCD (pain and fatigue) is still scarce. OBJECTIVE: This preliminary study aimed to test the utility of the SREP protocol for detecting pain sensitisation in patients with SCD, and to evaluate the associations of pain sensitisation, pain threshold, and pain tolerance with the main clinical symptoms of SCD, pain and fatigue. METHODS: Twenty-two female outpatients with SCD and 20 healthy women participated. Pain threshold, pain tolerance, and pain sensitisation were assessed by algometry in the fingernail. Clinical pain, fatigue, anxiety, depression and pain catastrophizing were evaluated. RESULTS: No group differences were found in pain threshold and tolerance. However, using the SREP protocol, pain sensitisation was greater in patients than in healthy participants, even after controlling for psychological variables and body mass index. Pain threshold and tolerance were inversely associated with fatigue levels in the SCD group, with pain tolerance being the main predictor. CONCLUSIONS: Pain threshold and tolerance did not discriminate between patients and healthy individuals, but were useful for predicting fatigue severity in SCD. The SREP protocol provides a useful dynamic measure of pain for the discrimination and detection of enhanced pain sensitisation in patients with SCD, which could contribute to more personalised pain evaluations and treatment for these patients.

Healthcare Professionals' Knowledge, Attitudes, and Practices in the Assessment, and Management of Sickle-Cell Disease: A Meta-Aggregative Review.

BACKGROUND: Sickle Cell Disease (SCD) presents significant health challenges globally. Despite its prevalence in diverse geographical regions, there is a paucity of literature synthesizing evidence on healthcare professionals' knowledge, attitudes, and practices (KAP) toward SCD assessment and management. This meta-aggregative review systematically examined and synthesized existing qualitative research to elucidate healthcare professionals' KAP regarding SCD assessment and management. METHODS: This meta-aggregative review followed Aromataris and Pearson's guidelines and the PRISMA framework for systematic review reporting. The search was conducted in Scopus, PubMed, Embase, CINAHL Web of Science, Google Scholar, Dimensions AI, and HINARI. Quality appraisal was performed using the Joanna Briggs Institute tool. RESULTS: Healthcare professionals (HCPs) demonstrate varying levels of KAP toward SCD assessment and management. Studies reveal low-to-moderate levels of general knowledge among HCPs, with nurses often exhibiting poorer understanding than physicians. Deficiencies in awareness of specific interventions, such as chemoprophylaxis and prenatal diagnosis, are noted, along with gaps in SCD assessment and diagnosis, particularly in pain management and premarital screening. Attitudes toward SCD patients vary, and practices reveal inconsistencies and deficiencies, including inadequate nutritional counseling and barriers in emergency departments. However, interventions aimed at improving HCPs' KAP show promise in enhancing understanding and attitudes toward SCD, suggesting potential avenues for improvement. CONCLUSIONS: Educational initiatives targeted at both student nurses and practicing healthcare providers, coupled with the implementation of standardized protocols and guidelines, can enhance knowledge acquisition and promote consistent, high-quality care delivery. Future studies should improve the quality of their methods in this area of study.

The role of ultra-widefield imaging with navigated central and peripheral cross-sectional and three-dimensional swept source optical coherence tomography in ophthalmology: Clinical applications.

PURPOSE: To assess central and peripheral retinal and choroidal diseases using ultra-widefield (UWF) fundus imaging in combination with navigated central and peripheral cross-sectional and three-dimensional (3D) swept source optical coherence tomography (SS-OCT) scans. METHODS: Retrospective study involving 332 consecutive patients, with a nearly equal distribution of males and females. The mean age of patients was 52 years (range 18-92 years). Average refractive error was -3.80 D (range +7.75 to -20.75 D). RESULTS: The observations in this study demonstrate the efficacy of peripheral navigated SS-OCT in assessing various ocular conditions. The technology provides high-quality images of the peripheral vitreous, vitreoretinal interface, retina, and choroid, enabling visualization of vitreous floaters and opacities, retinal holes and tears, pigmented lesions, and peripheral retinal degenerations. 3D OCT scans enhance the visualization of these abnormalities and improve diagnostic and therapeutic decisions. CONCLUSION: Navigated central and peripheral cross-sectional and 3D SS-OCT scans offer significant complementary benefits in the assessment and management of retinal diseases. Their addition to UWF imaging provides a comprehensive view of central and peripheral ocular structures, aiding in early detection, precise anatomical measurements, and objective monitoring of disease progression. In addition, this technology serves as a valuable tool for patient education, a teaching tool for trainees, and documentation for medico-legal purposes.

A Unique Case of a Compound Heterozygosity of Hemoglobin Korle-Bu and Sickle Cell Trait in a Military Trainee.

Hemoglobin Korle-Bu (Hb KB) is a rare and likely under-reported hemoglobin (Hb) variant resulting from an unusual point mutation on the beta-globin chain. Hb KB is typically clinically silent, and there are limited reports of Hb KB heterozygosity compounded with other hemoglobinopathies that can present with varying clinical phenotypes. Here, we report a case of compound Hb KB heterozygosity with Hb S in an asymptomatic military trainee with a positive sickle cell screening test. Hb capillary and gel electrophoresis predicted a compound Hb S/D-Punjab overlap, which foretells a severe clinical phenotype. Sequencing of the Hb beta gene HBB demonstrated Hb KB, allowing for a diagnosis that fit his asymptomatic clinical phenotype and allowed for retention in the military.

Sickle Cell Screening in Adults: A Current Review of Point-of-Care Testing.

In adults, the sickle cell solubility test (SCST) is the most common screening test to determine the presence of hemoglobin S (HbS) within a blood sample. The assay is inexpensive, rapid, highly sensitive and specific. However, the SCST cannot accurately quantify the level of HbS in a test sample and requires confirmatory testing to distinguish between sickle trait and sickle cell disease. Despite these limitations, it remains the standard screening tool for HbS in a variety of settings such as screening in the US military or by the National Collegiate Athletic Association. With an increased awareness of the importance of screening for sickle cell in adults, we herein describe the current sensitivity, specificity, positive predictive value, and negative predictive value of this test. We also review overall clinical utility of this laboratory measure and briefly discuss new point-of-care techniques designed to overcome the SCST's shortcomings.

Empowering sickle cell disease care: the rise of TechnoRehabLab in Sub-Saharan Africa for enhanced patient's perspectives.

Sickle-cell Disease (SCD) is a major public health problem in Africa, and there are significant obstacles to its comprehensive management, particularly in terms of access to appropriate healthcare. This calls for inventive approaches to improve patients' prospects. Among the major challenges to be met are the primary and secondary prevention of certain serious complications associated with the disease, such as neurocognitive, motor and respiratory functional disorders. This perspective argues for the rapid creation of specific, cost-effective, technology-supported rehabilitation centres to advance SCD care, identify patients at high risk of stroke and implement tailored rehabilitation strategies. The TechnoRehabLab in Lubumbashi illustrates this shift in thinking by using cutting-edge technologies such as virtual reality (VR), serious games and mobile health to create a comprehensive and easily accessible rehabilitation framework. Diagnostic tools used to perform functional assessment can be used to identify cognitive, balance and walking deficits respectively. Transcranial Doppler enables early detection of sickle cell cerebral vasculopathy, making it possible to provide early and appropriate treatment. VR technology and serious games enable effective rehabilitation and cognitive stimulation, which is particularly advantageous for remote or community-based rehabilitation. In the context of African countries where there is a glaring disparity in access to digital resources, the TechnoRehabLab serves as a tangible example, demonstrating the flexibility and accessibility of technology-assisted rehabilitation. This perspective is an urgent call to governments, non-governmental organisations and the international community to allocate resources to the replication and expansion of similar facilities across Africa.

Selectins in Biology and Human Disease: Opportunity in E-selectin Antagonism.

Selectins are cell adhesion proteins discovered in the 1980s. As C-type lectins, selectins contain an essential calcium ion in the ligand-binding pocket and recognize the isomeric tetrasaccharides sialyl Lewisx (sLex) and sialyl Lewisa (sLea). Three selectins, E-selectin, P-selectin, and L-selectin, play distinct, complementary roles in inflammation, hematopoiesis, and tumor biology. They have been implicated in the pathology of diverse inflammatory disorders, and several selectin antagonists have been tested clinically. E-selectin plays a unique role in leukocyte activation, making it an attractive target for intervention, for example, in sickle cell disease (SCD). This review summarizes selectin biology and pathology, structure and ligand binding, and selectin antagonists that have reached clinical testing with an emphasis on E-selectin.

Emergency department 30-Day emergency department revisits among people with sickle cell disease: Variations in characteristics.

People with sickle cell disease (SCD) often have emergency department (ED) revisits. The characteristics of people with SCD with ED revisits were assessed in this study using Medicaid administrative claims data from California and Georgia, representing 2794 and 3641 individuals with SCD, respectively. In both states, those with 6+ primary care provider (PCP) encounters had the highest percentage of ED revisits. In California, those with 6+ hematology encounters had the lowest percentage of individuals with an ED revisit; in Georgia, those with 1-2 hematology encounters. Increasing access to hematologic care may reduce ED revisits among people with SCD.

A critical review of therapeutic interventions in sickle cell disease: Progress and challenges.

Sickle cell disease (SCD) is an autosomal recessive genetic disorder that occurs due to the point mutation in the ß-globin gene, which results in the formation of sickle hemoglobin (HbS) in the red blood cells (RBCs). When HbS is exposed to an oxygen-depleted environment, it polymerizes, resulting in hemolysis, vaso-occlusion pain, and impaired blood flow. Still, there is no affordable cure for this inherited disease. Approved medications held promise but were met with challenges due to limited patient tolerance and undesired side effects, thereby inhibiting their ability to enhance the quality of life across various individuals with SCD. Progress has been made in understanding the pathophysiology of SCD during the past few decades, leading to the discovery of novel targets and therapies. However, there is a compelling need for research to discover medications with improved efficacy and reduced side effects. Also, more clinical investigations on various drug combinations with different mechanisms of action are needed. This review comprehensively presents therapeutic approaches for SCD, including those currently available or under investigation. It covers fundamental aspects of the disease, such as epidemiology and pathophysiology, and provides detailed discussions on various disease-modifying agents. Additionally, expert insights are offered on the future development of pharmacotherapy for SCD.

Sickle cell disease in Indian tribal population: Findings of a multi-centre Indian SCD registry.

BACKGROUND: Sickle cell disease (SCD) registries provide crucial real-world data on demographics, epidemiology, healthcare, patient outcomes, and treatment efficacy. This paper presents findings from the Indian SCD Registry (ISCDR) on clinical manifestations, crisis episodes, disease management, and healthcare utilization in patients with SCD from 12 primary health centres (PHCs) in six tribal districts of India. METHODS: The ISCDR was introduced along with a three-tier screening process. Its Android-based application incorporates two electronic case report forms for patient data collection over one year. This paper presents a year's data from the ISCDR's 324 patients with SCD. RESULTS: Patients with SCD, aged one to 65 years, exhibited varied clinical manifestations. Most patients (85.2 %) were unaware of their SCD status before enrolling in ISCDR. Moderate to severe anaemia was prevalent (66.05 % and 30.56 %, respectively). Pain was a common complaint (80.86 %; CI: 76.17-85.00), while symptoms of stroke included sudden severe headaches (34.57 %; CI: 29.40-40.02). Common splenic sequestration symptoms included stomach pain (42.90 %; CI: 37.44-48.49) and abdominal tenderness (13.27 %; CI: 9.77-17.46), as a sign. Healthcare utilization was high, with 96.30 % receiving treatment and 83.64 % consuming hydroxyurea. Hospitalization occurred for 38.27 % (CI: 32.95-43.81), and 12.04 % (CI: 8.70-16.09) had blood transfusion during last year. CONCLUSIONS: ISCDR serves as a dynamic digital database on SCD epidemiology, clinical aspects, treatment and healthcare utilization. Notably, many patients lacked prior awareness of their SCD status, underscoring the need for improved awareness and care management. Integrating the registry into the national programme can streamline treatment implementation, prioritize management approaches, and optimize individual benefits.

Retrospective Cohort Study of Sickle Cell Disease and Large Vessel Retinal Vascular Occlusion Risk in a National US Database.

OBJECTIVE: To determine if differences exist in the risk of developing large vessel retinal vascular occlusions in patients with sickle cell states. DESIGN: Retrospective cohort study. PARTICIPANTS: Patients with sickle cell disease or trait evaluated by an ophthalmologist were compared to matched controls without sickle cell disease or trait also evaluated by an ophthalmologist. METHODS: This study used deidentified data from a national database (2006-2024), using International Classification of Diseases 10 codes to select for retinal vascular occlusions. Propensity score matching was performed with respect to age, sex, race, ethnicity, smoking, hypertension, diabetes, dyslipidemias, and obesity, resulting in HbSS, HbSC, and sickle cell trait (SCT) cohorts and matched control cohorts. MAIN OUTCOME MEASURES: Risk ratios and 95% confidence intervals (CI) of retinal vascular occlusion diagnosis, including central retinal artery occlusion (CRAO), branch retinal artery occlusion (BRAO), central retinal venous occlusion (CRVO), branch retinal venous occlusion (BRVO), and corneal dystrophy as a negative control, given sickle cell disease or trait. RESULTS: After propensity score matching, HbSS (n=10,802, mean ± standard deviation age of 38.6 ± 20.6 years), HbSC (n=4,296, 34.3 ± 17.8 years), and SCT (n=15,249, 39.8 ± 23.7 years) cohorts were compared to control cohorts (n=10,802, 38.7 ± 20.7 years; n=4,296, 34.6 ± 18.0 years; n=15,249, 39.9 ± 23.8 years, respectively). Patients with sickle cell disease (HbSS) had higher risk of developing any retinal vascular occlusion (RR 2.33; 95% CI 1.82-3.00), CRAO (RR 2.71; 95% CI 1.65-4.47) and BRAO (RR 4.90; 95% CI 2.48-9.67) than matched controls. Patients with HbSC disease had higher risk (RR 3.14; 95% CI 1.95-5.06) of developing any retinal vascular occlusion than matched controls without sickle cell disease. Patients with sickle cell trait did not have higher risk of developing retinal vascular occlusions (RR 1.01; 95% CI 0.81-1.26) than matched controls. CONCLUSIONS: In a retrospective cohort study, patients with HbSS sickle cell disease have an increased risk of developing retinal vascular occlusions, and more specifically CRAO and BRAO compared to patients without sickle cell disease.

Transcriptional Repressor BCL11A in Erythroid Cells.

BCL11A, a zinc finger repressor, is a stage-specific transcription factor that controls the switch from fetal (HbF, α2γ2) to adult (HbA, α2ß2) hemoglobin in erythroid cells. While BCL11A was known as a factor critical for B-lymphoid cell development, its relationship to erythroid cells and HbF arose through genome-wide association studies (GWAS). Subsequent work validated its role as a silencer of γ-globin gene expression in cultured cells and mice. Erythroid-specific loss of BCL11A rescues the phenotype of engineered sickle cell disease (SCD) mice, thereby suggesting that downregulation of BCL11A expression might be beneficial in patients with SCD and ß-thalassemia. Common genetic variation in GWAS resides in an erythroid-specific enhancer within the BCL11A gene that is required for its own expression. CRISPR/Cas9 gene editing of the enhancer revealed a GATA-binding site that confers a large portion of its regulatory function. Disruption of the GATA site leads to robust HbF reactivation. Advancement of a guide RNA targeting the GATA-binding site in clinical trials has recently led to approval of first-in-man use of ex vivo CRISPR editing of hematopoietic stem/progenitor cells (HSPCs) as therapy of SCD and ß-thalassemia. Future challenges include expanding access and infrastructure for delivery of genetic therapy to eligible patients, reducing potential toxicity and costs, exploring prospects for in vivo targeting of hematopoietic stem cells (HSCs), and developing small molecule drugs that impair function of BCL11A protein as an alternative option.

International Society for Cell & Gene Therapy Stem Cell Engineering Committee report on the current state of hematopoietic stem and progenitor cell-based genomic therapies and the challenges faced.

Genetic manipulation of hematopoietic stem cells (HSCs) is being developed as a therapeutic strategy for several inherited disorders. This field is rapidly evolving with several novel tools and techniques being employed to achieve desired genetic changes. While commercial products are now available for sickle cell disease, transfusion-dependent ß-thalassemia, metachromatic leukodystrophy and adrenoleukodystrophy, several challenges remain in patient selection, HSC mobilization and collection, genetic manipulation of stem cells, conditioning, hematologic recovery and post-transplant complications, financial issues, equity of access and institutional and global preparedness. In this report, we explore the current state of development of these therapies and provide a comprehensive assessment of the challenges these therapies face as well as potential solutions.