bims-sicedi 2024-12-01 papers

Int J Mol Sci. 2024 Nov 05. pii: 11886. [Epub ahead of print]25(22):

Genetic Modifiers of Hemoglobin Expression from a Clinical Perspective in Hemoglobinopathy Patients with Beta Thalassemia and Sickle Cell Disease.

International Hemoglobinopathy Research Network (INHERENT)

Hemoglobinopathies, namely β-thalassemia and sickle cell disease (SCD), are hereditary diseases, characterized by molecular genetic aberrations in the beta chains of hemoglobin. These defects affect the normal production of hemoglobin with severe anemia due to less or no amount of beta globins in patients with β-thalassemia (quantitative disorder), while SCD is a serious disease in which a mutated form of hemoglobin distorts the red blood cells into a crescent shape at low oxygen levels (qualitative disorder). Despite the revolutionary progress in recent years with the approval of gene therapy and gene editing for specific patients, there is an unmet need for highlighting the mechanisms influencing hemoglobin production and for the development of novel drugs and targeted therapies. The identification of the transcription factors and other genetic modifiers of hemoglobin expression is of utmost importance for discovering novel therapeutic approaches for patients with hemoglobinopathies. The aim of this review is to describe these complex molecular mechanisms and pathways affecting hemoglobin expression and to highlight the relevant investigational approaches or pharmaceutical interventions focusing on restoring the hemoglobin normal function by linking the molecular background of the disease with the clinical perspective. All the associated drugs increasing the hemoglobin expression in patients with hemoglobinopathies, along with gene therapy and gene editing, are also discussed.

Keywords: DNA methylation; HbA2 (α2δ2); adult (α2β2) hemoglobin (HbA); fetal (α2γ2) hemoglobin (HbF); gene editing; gene therapy; genetic modifiers; hemoglobin expression; hemoglobinopathies; hereditary persistence of fetal hemoglobin (HPFH); histone modification; hydroxyurea (HU); sickle cell disease (SCD); β-thalassemia; γ-globin gene expression

DOI: https://doi.org/10.3390/ijms252211886

Int J Mol Sci. 2024 Nov 15. pii: 12290. [Epub ahead of print]25(22):

Accompanying Hemoglobin Polymerization in Red Blood Cells in Patients with Sickle Cell Disease Using Fluorescence Lifetime Imaging.

Fernanda Aparecida Borges da Silva, João Batista Florindo, Amilcar Castro de Mattos, Fernando Ferreira Costa, Irene Lorand-Metze, Konradin Metze.

In recent studies, it has been shown that fluorescence lifetime imaging (FLIM) may reveal intracellular structural details in unstained cytological preparations that are not revealed by standard staining procedures. The aim of our investigation was to examine whether FLIM images could reveal areas suggestive of polymerization in red blood cells (RBCs) of sickle cell disease (SCD) patients. We examined label-free blood films using auto-fluorescence FLIM images of 45 SCD patients and compared the results with those of 27 control persons without hematological disease. All control RBCs revealed homogeneous cytoplasm without any foci. Rounded non-sickled RBCs in SCD showed between zero and three small intensively fluorescent dots with higher lifetime values. In sickled RBCs, we found additionally larger irregularly shaped intensively fluorescent areas with increased FLIM values. These areas were interpreted as equivalent to polymerized hemoglobin. The rounded, non-sickled RBCs of SCD patients with homogeneous cytoplasm were not different from those of the erythrocytes of control patients in light microscopy. Yet, variables from the local binary pattern-transformed matrix of the FLIM values per pixel showed significant differences between non-sickled RBCs and those of control cells. In a linear discriminant analysis, using local binary pattern-transformed texture features (mean and entropy) of the erythrocyte cytoplasm of normal appearing cells, the final model could distinguish between SCD patients and control persons with an accuracy of 84.7% of the patients. When the classification was based on the examination of a single rounded erythrocyte, an accuracy of 68.5% was achieved. Employing the Linear Discriminant Analysis classifier method for machine learning, the accuracy was 68.1%. We believe that our study shows that FLIM is able to disclose the topography of the intracellular polymerization process of hemoglobin in sickle cell disease and that the images are compatible with the theory of the two-step nucleation. Furthermore, we think that the presented technique may be an interesting tool for the investigation of therapeutic inhibition of polymerization.

Keywords: auto-fluorescence; fluorescence lifetime imaging; hemoglobin; machine learning; polymerization

DOI: https://doi.org/10.3390/ijms252212290

Blood Adv. 2024 Nov 27. pii: bloodadvances.2024013693. [Epub ahead of print]

Is Allogeneic Transplantation for Sickle Cell Disease Still Relevant in the Era of Gene Therapy?

Richard J Jones, Adetola A Kassim, Robert A Brodsky, Michael R DeBaun.

Sickle cell disease (SCD) is the most common inherited blood disease. Disease-modifying therapy and supportive care have improved the survival of children with SCD in the United States and Europe. Yet, adults with SCD continue to have high risks of morbidity and early death. Recently, two FDA-approved genetic therapies offer the potential for a short-term decrease in acute vaso-occlusive pain events if not cure. Allogeneic hematopoietic cell transplantation (alloHCT) is also curative, but until recently was constrained by limited donor availability and the risks of graft-versus-host disease, graft rejection, and death. Importantly, recent advances have attenuated these barriers. Here, we discuss the current state of therapies with curative intent for SCD. Both genetic therapy and alloHCT offer the potential for cure for most with SCD. However, the cost (about five times higher), the current need for myeloablation, and associated late-health effects may make genetic therapies less favorable choices than alloHCT.

DOI: https://doi.org/10.1182/bloodadvances.2024013693

Transfusion. 2024 Nov 24.

Adding hydroxyurea to chronic transfusion therapy for sickle cell anemia reduces transfusion burden.

Robert Sheppard Nickel, Stefanie Margulies, Karuna Panchapakesan, Elizabeth Chorvinsky, Gustavo Nino, Marcin Gierdalski, James Bost, Naomi L C Luban, Jennifer Webb.

BACKGROUND: Chronic red blood cell (RBC) transfusion is an established therapy to prevent stroke in patients with sickle cell anemia (SCA). It is unclear if adding daily hydroxyurea treatment to chronic transfusion is beneficial.
STUDY DESIGN AND METHODS: We conducted a phase 2 clinical trial (NCT03644953) investigating the addition of dose-escalated hydroxyurea to chronic transfusion for patients with SCA receiving simple chronic transfusion for stroke prevention. Simple chronic transfusion therapy was administered as per the same protocol before and after hydroxyurea treatment in which the volume transfused was dependent on the pretransfusion hemoglobin (Hb).
RESULTS: A total of 14 participants enrolled with nine completing one year of combination hydroxyurea and transfusion (HAT) therapy after reaching hydroxyurea target dose. No participant who discontinued the study prematurely had a serious adverse event attributed to HAT. Among the nine participants who completed the study, eight participants achieved a reduction in RBC transfusion volume with a median reduction of -19.4 mL/kg/year (interquartile range -31.8, -2.8 mL/kg/year), p = .02, when comparing pre- and post-HAT time periods. With the addition of hydroxyurea participants had a significant increase in pretransfusion Hb S% but this was balanced by an increased Hb F% and decreased lactate dehydrogenase. One participant developed a pretransfusion Hb >11 g/dL and Hb S > 45% that required holding hydroxyurea and changing to partial manual exchange transfusions. No patient had evidence of cerebrovascular disease progression.
DISCUSSION: Hydroxyurea added to chronic transfusion therapy for patients with SCA is feasible and decreases RBC transfusion volume requirements.

Keywords: blood conservation; chronic transfusion; hydroxyurea; sickle cell disease; stroke prevention

DOI: https://doi.org/10.1111/trf.18073

Science. 2024 Nov 29. 386(6725): 1010-1018

A tetramer of BCL11A is required for stable protein production and fetal hemoglobin silencing.

Ge Zheng, Maolu Yin, Stuti Mehta, I-Te Chu, Stacy Wang, Alia AlShaye, Kirstin Drainville, Altantsetseg Buyanbat, Frédérique Bienfait, Karin Tenglin, Qian Zhu, Stuart H Orkin.

Down-regulation of BCL11A protein reverses the fetal (HbF, α2γ2) to adult (HbA, α2β2) hemoglobin switch and is exploited in gene-based therapy for hemoglobin disorders. Because of reliance on ex vivo cell manipulation and marrow transplant, such therapies cannot lessen disease burden. To develop new small-molecule approaches, we investigated the state of BCL11A protein in erythroid cells. We report that tetramer formation mediated by a single zinc finger (ZnF0) is required for production of steady-state protein. Beyond its role in protein stability, the tetramer state is necessary for γ-globin gene repression, because an engineered monomer fails to engage a critical co-repressor complex. These aspects of BCL11A protein production identify tetramer formation as a vulnerability for HbF silencing and provide opportunities for drug discovery.

DOI: https://doi.org/10.1126/science.adp3025

BMJ Open. 2024 Nov 28. 14(11): e084825

Protocol for a multicentric, double-blind, randomised controlled trial of hyperbaric oxygen therapy (HBOT) versus sham for treating vaso-occlusive crisis (VOC) in sickle cell disease (SCD) in patients aged 8 years or older (HBOT-SCD study).

INTRODUCTION: Sickle cell disease (SCD) is one of the most common genetic diseases in the world, annually affecting approximately 310 000 births and causing >100 000 deaths. Vaso-occlusive crisis (VOC) is the most frequent complication of SCD, leading to bone pain, thoracic pain (acute chest syndrome) and/or abdominal spasms. It is the main cause of mortality in patients with SCD, reducing life expectancy. Hyperbaric oxygen therapy (HBOT) is a safe and well-established method of increasing tissue oxygen delivery immediately by up to 10-fold to 20-fold. In the context of VOC, HBOT has the potential to limit sickling. A previous pilot study of nine patients showed the safety and potential benefits of HBOT on VOC-induced pain. Our study aimed to assess the clinical safety and effectiveness of HBOT for treating VOC, its biological mechanisms of actions and its cost-effectiveness.
METHODS AND ANALYSIS: This is a multicentric, triple-blinded, randomised controlled trial. Patients aged 8 years or above with a diagnosed major form of SCD, presenting at one of the participating centres' emergency departments (EDs) with a VOC requiring level 3 analgesia (according to WHO definition), will be eligible. Exclusion criteria are pregnancy, mechanical ventilation, previous history of stroke or prior transcranial Doppler ultrasound anomaly, contraindication to HBOT and the need for above 2 L/min of oxygen. All patients will receive the usual care for VOCs, including hydration, analgesics, normobaric oxygen therapy and when medically indicated, antibiotic therapy and/or transfusions. Within 24 hours of their arrival in the ED (or longer in specific cases), and after obtaining informed consent, patients will be randomised into the HBOT intervention group (2.0 atmosphere absolute (ATA), 90 min, FIO2=1) or the sham group (1.3 ATA, 90 min, FIO2=0.21). After their first HBOT session, patients will return to their acute-care ward. Patients in both arms will undergo a second and third session within 24-36 hours of the first, unless their Visual Analogue Scale (VAS)-pain is ≤2 without use of level 3 analgesics. The difference in the pain-VAS before and after HBOT and other outcomes will be compared between the intervention and sham groups. Our composite primary outcome will be (1) the change in global VAS-pain 6 hours after initiation of HBOT; (2) the number of patients with a VAS-pain score >4 and/or a morphine dosage >1 mg/hour intravenous after the HBOT/sham session. Other outcomes to be reported are morphine usage, length of stay, biological parameters, satisfaction, complications and cost.
ETHICS AND DISSEMINATION: Ethical approval CER Geneva 2019-01707 (last submission V.5.1, 06.15.2023). The results of the studies will be disseminated by several media, including publications in peer-reviewed international medical journals, and presentations at national and/or international conferences.
TRIAL REGISTRATION NUMBER: NCT04978116.

Keywords: Anaemia; Emergency Service, Hospital; INTERNAL MEDICINE

DOI: https://doi.org/10.1136/bmjopen-2024-084825

Cureus. 2024 Oct;16(10): e72269

Vitamin D Deficiency and Avascular Necrosis in Patients With Sickle Cell Disease: A Retrospective Cohort Study.

Abdullah J Tammas, Luluh B Albehlal, Fahad Alabbas.

Introduction Sickle cell disease (SCD) is an inherited hemoglobinopathy with complex multi-systemic involvement. Avascular necrosis (AVN) is a devastating complication among patients with SCD. Vitamin D deficiency (VDD) is a common finding in SCD patients. However, there is a paucity of research that evaluates the potential role of VDD as a risk factor for AVN in patients with SCD. This study aimed to assess the association between VDD and AVN and determine the patterns of presentation, risk factors, diagnosis, and treatment of AVN in patients with SCD. Methods We conducted a retrospective cohort study of consecutive SCD patients diagnosed with VDD from January 2020 to December 2022 at Prince Sultan Medical Military City (PSMMC), Riyadh, Saudi Arabia. Inclusion criteria: (1) adults and children with confirmed SCD and (2) tested for VDD. We excluded patients who underwent bone marrow transplants. The associations were assessed using the chi-square test. Logistic regression was performed to control for confounding. Results The study included 711 eligible patients; 271 (38%) were children. VDD affected 301/711 (42.3%). VDD was noticed in 32.2% and 48.1% of children and adults, respectively. AVN was diagnosed in 127/711 (17.9%) patients. The mean age at AVN diagnosis was 30.9 ± 11 years. The most common presentation of AVN was chronic joint pain (> 95%). The most frequently affected joint was the hip (86%). The majority of patients (76.4%) were late in stage at diagnosis of AVN (III/IV). Patients with a history of VDD were significantly associated with a higher risk of AVN (p < 0.001). Using multivariate logistic regression, SCD patients with VDD have 9.79 times the odds of AVN compared with SCD patients without VDD (OR 9.79; 95% CI: 5.25 - 18.26). Other statistically significant risk factors for AVN included frequent vaso-occlusive crises, older age, history of acute chest syndrome, and high body mass index. Conclusion AVN is a significant cause of morbidity in our SCD cohort. Most of the patients had advanced AVN disease. VDD is an independent risk factor for the occurrence of AVN. Well-designed randomized trials are required to determine the effect of vitamin D supplementation in reducing AVN in patients with SCD.

Keywords: adult; avascular necrosis; avn; children; saudi arabia; scd; sickle cell disease; vdd; vitamin d deficiency

DOI: https://doi.org/10.7759/cureus.72269