bims-conane Biomed News
on Congenital anemias
Issue of 2024–09–15
fourteen papers selected by
João Conrado Khouri dos Santos, Universidade de São Paulo



  1. Annu Rev Pharmacol Toxicol. 2024 Sep 11.
      Sickle cell disease (SCD) is a hereditary blood disorder characterized by the presence of abnormal hemoglobin molecules and thus distortion (sickling) of the red blood cells. SCD causes chronic pain and organ damage and shortens life expectancy. Gene therapy emerges as a potentially curative approach for people with SCD who lack a matched sibling donor for hematopoietic stem cell transplantation. Here, we review recent progress in gene therapy for SCD and focus on innovative technologies that target the genetic roots of the disease. We also review the challenges associated with gene therapy, including oncogenic risks, and the need for refined delivery methods. Despite these hurdles, the rapidly evolving landscape of gene therapy for SCD raises hope for a paradigm shift in the treatment of this debilitating disease. As research progresses, a deeper understanding of the molecular mechanisms involved and continuous improvements in gene-editing technologies promise to bring gene therapy for SCD closer to mainstream clinical application, offering a transformative, curative option for patients with this genetic disorder.
    DOI:  https://doi.org/10.1146/annurev-pharmtox-022124-022000
  2. Curr Opin Hematol. 2024 Aug 27.
       PURPOSE OF REVIEW: The human spleen clears the blood from circulating microorganisms and red blood cells (RBCs) displaying alterations. This review analyzes how generic mechanisms by which the spleen senses RBC, such pitting, trapping and erythrophagocytosis, impact the pathogenesis of twos major spleen-related diseases, malaria and sickle cell disease (SCD).
    RECENT FINDINGS: Scintigraphy, functional histology, comparison of circulating and splenic RBC, ex-vivo perfusion of human spleens and in-silico modeling enable relevant exploration of how the spleen retains and processes RBC in health and disease. Iterative cross-validations between medical observations, in-vitro experiments and in-silico modeling point to mechanical sensing of RBC as a central event in both conditions. Spleen congestion is a common pathogenic process explaining anemia and splenomegaly, the latter carrying a risk of severe complications such as acute splenic sequestration crisis and hypersplenism in SCD. Sickling of hemoglobin S-containing RBC may contribute but not trigger these complications.
    SUMMARY: Ongoing progress in the exploration and understanding of spleen-related complications in malaria and SCD open the way to optimized prognosis evaluation and therapeutic applications.
    DOI:  https://doi.org/10.1097/MOH.0000000000000839
  3. Mediterr J Hematol Infect Dis. 2024 ;16(1): e2024068
      In the last ten years, a consistent number of clinical studies have evaluated different gene approaches for the treatment of patients with sickle cell disease (SCD) and transfusion-dependent β-thalassemia (TDT). Initial studies of gene therapy for hemoglobinopathies involved the use of lentiviral vectors to add functional copies of the gene encoding β-globin in defective CD34 cells; more recently, gene editing techniques have been used involving either CRISPR-Cas9, transcription activation-like effector protein nuclease, zinc finger nuclease, and base editing to either induce fetal hemoglobin production at therapeutic levels or to genetically repair the underlying molecular defect causing the disease. Here, we review recent gene editing studies that have started the development of a new era in the treatment of hemoglobinopathies and, in general, monoallelic hereditary diseases.
    Keywords:  Gene editing; Hemoglobinopathies; Sickle Cell Anemia; Thalassemia; gene therapy
    DOI:  https://doi.org/10.4084/MJHID.2024.068
  4. Blood Adv. 2024 Sep 12. pii: bloodadvances.2024013504. [Epub ahead of print]
      In a Phase 1 study (NCT04000165), we established proof-of-concept for activating pyruvate kinase (PK) in sickle cell disease (SCD) as a viable anti-sickling therapy. AG-348 (mitapivat), a PK activator, increased adenosine triphosphate (ATP) and decreased 2,3- diphosphoglycerate levels while patients were on treatment in line with the mechanism of the drug. We noted that the increased hemoglobin persisted for 4 weeks after stopping AG-348 until the end of study (EOS). Here, we investigated the pathways modulated by activating PK that may contribute to the improved red blood cell (RBC) survival after AG-348 cessation. We evaluated frozen whole blood samples taken at multiple timepoints from the patients in the Phase 1 study, from which RBC ghosts were isolated and analyzed by Western blotting for tyrosine-phosphorylation of band 3 (Tyr-p-bd3), ankyrin-1 and intact (active) protein tyrosine phosphatase 1B (PTP1B) levels. We observed a significant dose-dependent decrease in mean Tyr-p-bd3 from baseline in the subjects, accompanied by increase in levels of membrane-associated ankyrin-1 and intact PTP1B, all of which returned to near baseline by EOS. As PTP1B is cleaved (inactivated) by intracellular Ca2+-dependent calpain, we next measured the effect of AG-348 on ATP production and calpain activity, and the plasma membrane Ca2+ ATPase pump (PMCA)-mediated efflux kinetics in HbAA and HbSS erythrocytes. AG-348 treatment increased ATP levels, decreased calpain activity, and increased Ca2+ efflux. Altogether, our data indicate that ATP increase is a key mechanism underlying the increase in hemoglobin levels upon PK activation in SCD.
    DOI:  https://doi.org/10.1182/bloodadvances.2024013504
  5. Front Hematol. 2023 ;pii: 1040720. [Epub ahead of print]2
       Background: Sickle cell disease (SCD) is a severe hereditary form of anemia that contributes between 50% and 80% of under-five mortality in Africa. Eleven thousand babies are born with SCD annually in Tanzania, ranking 4th after Nigeria, the Democratic Republic of Congo and India. The absence of well-described SCD cohorts is a major barrier to health research in SCD in Africa.
    Objective: This paper describes the Sickle Pan African Consortium (SPARCO) database in Tanzania, from the development, design of the study instruments, data collection, analysis of data and management of data quality issues.
    Methods: The SPARCO registry used existing Muhimbili Sickle Cell Cohort (MSC) study case report forms (CRF) and later harmonized data elements from the SickleInAfrica consortium to develop Research Electronic Data Capture (REDCap) instruments. Patients were enrolled through various strategies, including mass screening following media sensitization and health education events during World Sickle Cell Day each June and the SCD awareness month in September. Additional patients were identified through active surveillance of previously participating patients in the MSC.
    Results: Three thousand eight hundred patients were enrolled between October 2017 and May 2021. Of these, 1,946 (51.21%) were males and 1,864 (48.79%) were females. The hemoglobin phenotype distribution was 3,762 (99%) HbSS, 3 (0.08%) HbSC and 35 (0.92%) HbSb +thalassemia. Hemoglobin levels, admission history, blood transfusion and painful events were recorded from December 2017 to May 2021.
    Conclusion: The Tanzania SPARCO registry will improve healthcare for SCD in Africa through the facilitation of collaborative data-driven research for SCD.
    Keywords:  REDCap; Tanzania; case report form; data science; registry; sickle cell disease
    DOI:  https://doi.org/10.3389/frhem.2023.1040720
  6. Hematology. 2024 Dec;29(1): 2399361
       OBJECTIVE: The α-globin fusion gene between the HBA2 and HBAP1 genes, is clinically important in thalassemia screening because this fusion gene can cause severe hemoglobin (Hb) H disease when combined with α0 -thalassemia (α0 -thal). In this study, we evaluate the red blood cell parameters of α-thalassemia fusion gene in southern China.
    METHOD: Study samples suspected of α-thalassemia fusion gene were collected and confirmed by PCR-sequencing from one medical lab center in southern China. Their genotypes and phenotypes were analyzed.
    RESULTS: A total of 266 cases of α-thalassemia fusion gene were confirmed in our lab from 2017 to 2023, most of them were from Hainan province (169 cases) and Huadu district of Guangzhou (21 cases), the nationality of 143 cases from Hainan was identified, with 71.3% (102/143) being from the Li minority. The Hb, MCV, MCH for αα/(αα)fusion in adult males were 143.5±11.83g/L, 81.51±4.39 fl, and 26.26±1.29 pg, respectively; and in females, they were 126.69±12.89 g/L, 80.10±4.05 fl, 25.8±2.04 pg, respectively. All 12 cases (αα) Fusion/ --SEA showed anemia with decreased Hb, MCV and MCH.
    CONCLUSION: The carriers of α-globin fusion gene heterozygotes are clinically silent and exhibit an α+ phenotype. Individuals with (αα)Fusion/--SEA show apparent anemia. This α-globin fusion gene is relatively common in southern China, specifically among the Li minority of Hainan province. Therefore, it should be taken into account for genetic counseling purposes.
    Keywords:  China; Guangdong, -α4.2; HBA2; Thalassemia; gene testing; genotype; α-globin gene fusion
    DOI:  https://doi.org/10.1080/16078454.2024.2399361
  7. Medicine (Baltimore). 2024 Sep 06. 103(36): e39475
       BACKGROUND: In the present review, we aimed to synthesize evidence from studies on the safety and effectiveness of prophylactic blood transfusion in pregnant women with sickle cell disease.
    MATERIAL AND METHODS: To gather relevant information, we conducted systematic electronic searches of databases such as SCOPUS, Medline via PubMed, Web of Science, and Cochrane Central Register of Controlled Trials. We included both retrospective and prospective studies that examined the impact of prophylactic blood transfusions during pregnancy. The collected data were analyzed using Review Manager, version 5.3.
    RESULTS: The review included 15 cohort studies. The overall findings indicated a preference for the prophylactic blood transfusion group over the control group across several key parameters. Specifically, the prophylactic group demonstrated lower rates of maternal mortality (odds ratio [OR] = 0.33; 95% confidence interval [CI] = 0.10-1.13; P = .08), reduced incidence of vaso-occlusive painful events (OR = 0.31; 95% CI = 0.14-0.73; P = .007), fewer pulmonary complications (OR = 0.21; 95% CI = 0.08-0.53; P = .001), decreased perinatal mortality (OR = 0.35; 95% CI = 0.17-0.75; P = .03), and lower likelihood of preterm birth (OR = 0.67; 95% CI = 0.47-0.96; P = .02). Notably, statistically significant heterogeneities were observed in the pooled effect estimates.
    CONCLUSION: The present meta-analysis indicated that prophylactic blood transfusion in pregnant women with sickle cell disease may improve maternal and fetal outcomes. However, substantial variations in the methodology and transfusion protocols among the included studies limited the credibility of the current evidence supporting the routine clinical use of prophylactic transfusion for SCD during pregnancy.
    DOI:  https://doi.org/10.1097/MD.0000000000039475
  8. Cureus. 2024 Aug;16(8): e66628
      Sickle cell disease includes various inherited hemoglobinopathies due to the production of abnormal hemoglobin molecules. This can lead to significant clinical complications and sequelae. Hemoglobin SC (HbSC) is a notable variant of SCD, requiring early diagnosis and management to prevent severe outcomes. This case report highlights the critical need for SCD screening, particularly among immigrant populations where current U.S. guidelines do not mandate arrival screening. We present the case of a West African male, age 45, with chronic osteomyelitis, who developed a life-threatening pulmonary embolism (PE) due to peripherally inserted central catheter (PICC line) thrombosis, triggering a hemolytic crisis and thereby revealing HbSC disease. The authors of this report advocate for routine SCD screening in high-risk populations through targeted screening programs. Through multidisciplinary management and public health initiatives, we can address the gap in screening and ensure early detection and treatment of SCD in vulnerable populations.
    Keywords:  acute pulmonary embolism; deep vein thrombosis (dvt); general internal medicine; hemoglobin sc disease; osteomyelitis; sickle cell complications; sickle cell crisis; sickle cell disease: scd; upper extremity dvt
    DOI:  https://doi.org/10.7759/cureus.66628
  9. J Pediatr (Rio J). 2024 Sep 06. pii: S0021-7557(24)00110-4. [Epub ahead of print]
       OBJECTIVE: This study aimed to investigate the epidemiological trends of Pediatric Sickle Cell Disease (SCD) in Brazil over the period 2008-2022, with a focus on understanding the incidence, mortality rates, and associated healthcare costs. The study explored potential associations between patient characteristics and the occurrence of crises in pediatric SCD cases.
    METHODS: A cross-sectional study was conducted, analyzing national annual rates of pediatric SCD hospitalizations using data from the FioCruz platform. Descriptive and inferential analyses, including time series and ARIMA regression, were employed. Economic dimensions were assessed using cost categorization. The study followed STROBE reporting guidelines.
    RESULTS: Data on 81,942 pediatric SCD hospitalizations were collected, with a predominance of crisis-related cases (74.08 %). Males and children under five years old were most affected. Regional disparities were observed, with the Southwest region recording the highest hospitalization rates. ICU costs were higher for crisis-related hospitalizations. Mortality rates were significantly higher for crisis-related cases (p < 0.001), with ARIMA regression indicating a significant association between hospitalizations for crisis-related cases and mortality.
    CONCLUSION: This study highlights the significant burden of pediatric SCD in Brazil, particularly crisis-related cases, suggesting a need for focused interventions. By prioritizing early detection, equitable access to healthcare, and evidence-based interventions, Brazil can mitigate the burden of SCD and improve patient outcomes. These findings contribute to informing public health policies and interventions aimed at addressing the challenges of pediatric SCD management in Brazil.
    Keywords:  Cost of illness; Global health; Pediatric; Public health; Sickle cell anemia
    DOI:  https://doi.org/10.1016/j.jped.2024.07.010
  10. Medicine (Baltimore). 2024 Sep 06. 103(36): e39358
       RATIONALE: Fanconi anemia (FA) is a hereditary disease caused by mutations in the genes involved in the DNA damage repair pathway. The FANCA gene is the most commonly pathogenic gene, accounting for more than 60% of all causative genes.
    PATIENT CONCERNS: The clinical case is a 3-year-old boy showed mild anemia and scattered bleeding spots the size of a needle tip all over his body.
    DIAGNOSES: Compound heterozygous mutation was identified in the FANCA gene in the FA case: c.1A > T from the father in exon 1; the deletion of chr16: 89857810-89858476 (exon13-14 del) from the mother; finally, the patient was diagnosed as Fanconi anemia.
    INTERVENTION: After diagnosis, the child received chemotherapy (Ara-C + Flu + Cy + ATG). Then, the hematopoietic stem cell transplantation and unrelated umbilical cord blood transfusion were performed.
    OUTCOMES: The child is recovering well and is in regular follow-up.
    CONCLUSION AND LESSONS: The discovery of new mutations in the FANCA gene enriches the genetic profile of FA and helps clinicians to further understand this disease and guide genetic counseling and prenatal diagnosis. Whole-exome sequencing is a powerful tool for diagnosing FA.
    DOI:  https://doi.org/10.1097/MD.0000000000039358
  11. Blood Adv. 2024 Sep 09. pii: bloodadvances.2024013333. [Epub ahead of print]
      β-thalassemia is an iron-loading anemia caused by homozygous mutation of the hemoglobin subunit β (HBB) gene. In β-thalassemia intermedia (βTI), a non-transfusion-dependent form of the disease, iron overload is caused by excessive absorption of dietary iron due to inappropriately low production of the iron-regulatory hormone hepcidin. Low hepcidin stabilizes the iron exporter ferroportin (FPN) on the basolateral membrane of enterocytes. High FPN activity may deplete intracellular iron and enhance expression of the predominant iron importer divalent metal-ion transporter 1 (DMT1). In mice, DMT1 mediates normal iron absorption under physiological conditions and excessive iron absorption in pathological iron overload (e.g., hereditary hemochromatosis). Here, we hypothesized that DMT1 drives elevated iron absorption in βTI. Accordingly, we crossed Hbbth3/+ mice, a pre-clinical model of βTI, with intestine-specific DMT1 KO mice. Ablation of intestinal DMT1 in Hbbth3/+ mice caused a pathophysiological shift from iron overload to an iron-deficiency phenotype with exacerbated anemia. DMT1 is thus required for iron absorption and iron loading in Hbbth3/+ mice. Based upon these outcomes, we further logically postulated that in vivo knockdown of intestinal DMT1 would mitigate iron loading in Hbbth3/+ mice. Ginger-derived, lipid nanoparticles carrying DMT1-specific (or control) siRNAs were administered by oral, intragastric gavage to 4-week-old Hbbth3/+ mice daily for 16 days. siRNA treatment reduced DMT1 expression by >80% and blunted iron loading, as indicated by significant reductions in liver iron and serum ferritin (which reflect body iron stores). These notable experimental outcomes establish intestinal DMT1 as a plausible therapeutic target to mitigate iron overload in βTI.
    DOI:  https://doi.org/10.1182/bloodadvances.2024013333
  12. JAMA Intern Med. 2024 Sep 09.
       Importance: Sickle cell disease (SCD), a clinically heterogenous genetic hemoglobinopathy, is characterized by painful vaso-occlusive episodes (VOEs) that can require hospitalization. Patients admitted with VOEs are often initially resuscitated with normal saline (NS) to improve concurrent hypovolemia, despite preclinical evidence that NS may promote erythrocyte sickling. The comparative effectiveness of alternative volume-expanding fluids (eg, lactated Ringer [LR]) for resuscitation during VOEs is unclear.
    Objective: To compare the effectiveness of LR to NS fluid resuscitation in patients with SCD and VOEs.
    Design, Setting, and Participants: This multicenter cohort study and target trial emulation included inpatient adults with SCD VOEs who received either LR or NS on hospital day 1. The Premier PINC AI database (2016-2022), a multicenter clinical database including approximately 25% of US hospitalizations was used. The analysis took place between October 6, 2023, and June 20, 2024.
    Exposure: Receipt of LR (intervention) or NS (control) on hospital day 1.
    Main Outcome and Measures: The primary outcome was hospital-free days (HFDs) by day 30. Targeted maximum likelihood estimation was used to calculate marginal effect estimates. Heterogeneity of treatment effect was explored in subgroups.
    Results: A total of 55 574 patient encounters where LR (n = 3495) or NS (n = 52 079) was administered on hospital day 1 were included; the median (IQR) age was 30 (25-37) years. Patients who received LR had more HFDs compared with those who received NS (marginal mean difference, 0.4; 95% CI, 0.1-0.6 days). Patients who received LR also had shorter hospital lengths of stay (marginal mean difference, -0.4; 95% CI, -0.7 to -0.1 days) and lower risk of 30-day readmission (marginal risk difference, -5.8%; 95% CI, -9.8% to -1.8%). Differences in HFDs between LR and NS were heterogenous based on fluid volume received: among patients who received less than 2 L, there was no difference in LR vs NS; among those who received 2 or more L, LR was superior to NS.
    Conclusion and Relevance: This cohort study found that, compared with NS, LR had a small but significant improvement in HFDs and secondary outcomes including 30-day readmission. These results suggest that, among patients with VOEs in whom clinicians plan to give volume resuscitation fluids on hospital admission, LR should be preferred over NS.
    DOI:  https://doi.org/10.1001/jamainternmed.2024.4428
  13. Am J Med Qual. 2024 Sep-Oct 01;39(5):39(5): 201-208
      An individualized management program for patients with sickle cell disease (SCD) was created to reduce health care utilization and cost. The program was implemented to standardize the management of patients with SCD. SCD encounters from January 2010 to December 2020 were reviewed for analysis. Preintervention utilization of inpatient, emergency room, and outpatient settings was compared to postintervention. There were 7114 encounters analyzed. Outpatient encounters increased from 36.5% to 70.9%; inpatient encounters decreased from 38.6% to 20.3%; and emergency department visits decreased from 20.3% to 8.8%. The number of high inpatient utilizers decreased 8.4% and the number of individuals who received any emergency care decreased 11.9%. When comparing average charges per time period, the median charge per encounter decreased by $1838 postintervention compared to preintervention. This newly implemented SCD program demonstrated success through shifting the care of the SCD patient to the outpatient setting rather than the emergency department or inpatient hospitalizations.
    DOI:  https://doi.org/10.1097/JMQ.0000000000000199