Mortality in sickle cell disease. Life expectancy and risk factors for early death

Pregnancy and assisted reproductive technology use in Australian female transfusion-dependent haemoglobinopathy patients: a 20-year retrospective analysis

BACKGROUND

In the last few decades, the life expectancy of patients with transfusion-dependent thalassaemia (TDT) and sickle cell disease (SCD) has improved significantly, in part because of improved iron chelation. Fertility challenges and pregnancy complications have historically limited reproductive options in this group; however, improved multi-disciplinary care has made infertility a chronic disease complication requiring attention. Despite this, there are very few reports and no Australian data describing fertility and pregnancy outcomes in this population.

AIMS

To identify the rate of assisted reproductive technologies (ART) utilisation in our female transfusion-dependent haemoglobinopathy patients and to establish the nature of maternal and neonatal complications in this cohort.

METHODS

A 20-year retrospective analysis (1997-2017) at an Australian centre captured data on conception rates, use of assisted reproductive techniques (ART), and pregnancy and neonatal outcomes in female transfusion-dependent haemoglobinopathy patients.

RESULTS

Conception was attempted in 14 women (11 TDT and three SCD) during the study period. A total of 28 pregnancies resulting in 25 live births were recorded. ART supported 13 conceptions. A positive association was not identified between elevated mean serum ferritin and ART use; however, all patients with an established diagnosis of hypogonadotropic hypogonadism (HH) required ART. Maternal complications included gestational diabetes mellitus and post-partum haemorrhage. There were no cardiac complications. Two-thirds of women underwent lower segment caesarean section, with prematurity complicating 20% of births. There were no neonatal or maternal deaths.

CONCLUSION

Pregnancy is an achievable goal for women with transfusion-dependent haemoglobinopathies, although the support of ART may be required in a subset of patients.

An Update on the Application of CRISPR Technology in Clinical Practice

The CRISPR/Cas system, an innovative gene-editing tool, is emerging as a promising technique for genome modifications. This straightforward technique was created based on the prokaryotic adaptive immune defense mechanism and employed in the studies on human diseases that proved enormous therapeutic potential. A genetically unique patient mutation in the process of gene therapy can be corrected by the CRISPR method to treat diseases that traditional methods were unable to cure. However, introduction of CRISPR/Cas9 into the clinic will be challenging because we still need to improve the technology's effectiveness, precision, and applications. In this review, we first describe the function and applications of the CRISPR-Cas9 system. We next delineate how this technology could be utilized for gene therapy of various human disorders, including cancer and infectious diseases and highlight the promising examples in the field. Finally, we document current challenges and the potential solutions to overcome these obstacles for the effective use of CRISPR-Cas9 in clinical practice.

Structural Insights into the DNA-Binding Mechanism of BCL11A: The Integral Role of ZnF6

The transcription factor BCL11A is a critical regulator of the switch from fetal hemoglobin (HbF: α 2 γ 2 ) to adult hemoglobin (HbA: α 2 β 2 ) during development. BCL11A binds at a cognate recognition site (TGACCA) in the γ-globin gene promoter and represses its expression. DNA-binding is mediated by a triple zinc finger domain, designated ZnF456. Here, we report comprehensive investigation of ZnF456, leveraging X-ray crystallography and NMR to determine the structures in both the presence and absence of DNA. We delve into the dynamics and mode of interaction with DNA. Moreover, we discovered that the last zinc finger of BCL11A (ZnF6) plays a special role in DNA binding and γ-globin gene repression. Our findings help account for some rare γ-globin gene promoter mutations that perturb BCL11A binding and lead to increased HbF in adults (hereditary persistence of fetal hemoglobin). Comprehending the DNA binding mechanism of BCL11A opens avenues for the strategic, structure-based design of novel therapeutics targeting sickle cell disease and β-thalassemia.

Genetic variants and effect modifiers of QT interval prolongation in patients with sickle cell disease

BACKGROUND

Sickle cell disease (SCD) is a common inherited blood disorder among African Americans (AA), with premature mortality which has been associated with prolongation of the heart rate-corrected QT interval (QTc), a known risk factor for sudden cardiac death. Although numerous genetic variants have been identified as contributors to QT interval prolongation in the general population, their impact on SCD patients remains unclear. This study used an unweighted polygenic risk score (PRS) to validate the previously identified associations between SNPs and QTc interval in SCD patients, and to explore possible interactions with other factors that prolong QTc interval in AA individuals with SCD.

METHODS

In SCD patients, candidate genetic variants associated with the QTc interval were genotyped. To identify any risk SNPs that may be correlated with QTc interval prolongation, linear regression was employed, and an unweighted PRS was subsequently constructed. The effect of PRS on the QTc interval was evaluated using linear regression, while stratification analysis was used to assess the influence of serum alanine transaminase (ALT), a biomarker for liver disease, on the PRS effect. We also evaluated the PRS with the two subcomponents of QTc, the QRS and JTc intervals.

RESULTS

Out of 26 candidate SNPs, five risk SNPs were identified for QTc duration under the recessive model. For every unit increase in PRS, the QTc interval prolonged by 4.0 ms (95% CI: [2.0, 6.1]; p-value: <0.001) in the additive model and 9.4 ms in the recessive model (95% CI: [4.6, 14.1]; p-value: <0.001). Serum ALT showed a modification effect on PRS-QTc prolongation under the recessive model. In the normal ALT group, each PRS unit increased QTc interval by 11.7 ms (95% CI: [6.3, 17.1]; p-value: 2.60E-5), whereas this effect was not observed in the elevated ALT group (0.9 ms; 95% CI: [-7.0, 8.8]; p-value: 0.823).

CONCLUSION

Several candidate genetic variants are associated with QTc interval prolongation in SCD patients, and serum ALT acts as a modifying factor. The association of a CPS1 gene variant in both QTc and JTc duration adds to NOS1AP as evidence of involvement of the urea cycle and nitric oxide metabolism in cardiac repolarization in SCD. Larger replication studies are needed to confirm these findings and elucidate the underlying mechanisms.

Characterizing epigenetic aging in an adult sickle cell disease cohort

ABSTRACT

Sickle cell disease (SCD) affects ∼100 000 predominantly African American individuals in the United States, causing significant cellular damage, increased disease complications, and premature death. However, the contribution of epigenetic factors to SCD pathophysiology remains relatively unexplored. DNA methylation (DNAm), a primary epigenetic mechanism for regulating gene expression in response to the environment, is an important driver of normal cellular aging. Several DNAm epigenetic clocks have been developed to serve as a proxy for cellular aging. We calculated the epigenetic ages of 89 adults with SCD (mean age, 30.64 years; 60.64% female) using 5 published epigenetic clocks: Horvath, Hannum, PhenoAge, GrimAge, and DunedinPACE. We hypothesized that in chronic disease, such as SCD, individuals would demonstrate epigenetic age acceleration, but the results differed depending on the clock used. Recently developed clocks more consistently demonstrated acceleration (GrimAge, DunedinPACE). Additional demographic and clinical phenotypes were analyzed to explore their association with epigenetic age estimates. Chronological age was significantly correlated with epigenetic age in all clocks (Horvath, r = 0.88; Hannum, r = 0.89; PhenoAge, r = 0.85; GrimAge, r = 0.88; DunedinPACE, r = 0.34). The SCD genotype was associated with 2 clocks (PhenoAge, P = .02; DunedinPACE, P < .001). Genetic ancestry, biological sex, β-globin haplotypes, BCL11A rs11886868, and SCD severity were not associated. These findings, among the first to interrogate epigenetic aging in adults with SCD, demonstrate epigenetic age acceleration with recently developed epigenetic clocks but not older-generation clocks. Further development of epigenetic clocks may improve their predictive ability and utility for chronic diseases such as SCD.

Differential clinical characteristics across traditional Chinese medicine (TCM) Syndromes in patients with sickle cell disease

Background

Pain is a common, debilitating, and poorly understood complication of sickle cell disease (SCD). The need for clinical pain management of SCD is largely unmet and relies on opioids as the main therapeutic option, which leads to a decreased quality of life (QoL). According to the literature, acupuncture has shown certain therapeutic effects for pain management in SCD. However, these clinical studies lack the guidance of Traditional Chinese Medicine (TCM) Syndrome Differentiation principles for treatment.

Aim

To characterize differences in clinical presentation amongst TCM diagnosed Syndromes in SCD patients.

Method

Fifty-two patients with SCD and 28 age- and sex-matched healthy controls (HCs) were enrolled in an ongoing trial of acupuncture. Each participant completed a series of questionnaires on pain, physical function, fatigue, sleep, anxiety, depression and QoL and underwent cold- and pressure-based quantitative sensory testing at baseline. Data on prescription opioid use over the 12 months prior to study enrollment was used to calculate mean daily morphine milligram equivalents (MME). Differences among the three TCM Syndromes were analyzed by one-way ANOVA followed by Tukey post hoc testing. Two-sample t-tests were used to compare SCD and HC groups.

Results

TCM diagnosis criteria classified SCD patients into one of three TCM Syndromes: (a) Equal; (b) Deficiency; and (c) Stagnation. The Stagnation group exhibited higher pain interference, physical dysfunction, nociplastic pain, fatigue, anxiety, depression, MME consumption and lower sleep quality and QoL compared to the Equal group. Few differences were observed between HCs and the Equal SCD group across outcomes. Deficiency and Stagnation groups were differentiated with observed- and patient-reported clinical manifestations.

Conclusion

These findings suggest that TCM diagnosed Syndromes in SCD can be differentially characterized using validated objective and patient-reported outcomes. Because characteristics of pain and co-morbidities in each SCD patient are unique, targeting specific TCM "Syndromes" may facilitate treatment effectiveness with a Syndrome-based personalized treatment plan that conforms to TCM principles. These findings lay the foundation for the development of tailored acupuncture interventions based on TCM Syndromes for managing pain in SCD. Larger samples are required to further refine and validate TCM diagnostic criteria for SCD.

Acute Chest Syndrome: A Bibliometric Analysis of the Top 100 Most Cited Articles

Acute chest syndrome (ACS) is a major cause of morbidity and mortality in patients with SCD (SCD). The analysis of research productivity and trends in ACS may serve as a valuable guide for investigators, institutions, and funding agencies to plan the future directions of research. The current review aims to evaluate the productivity and trends of publications related to ACS in adults by analyzing the top 100 most cited articles. A bibliometric analysis of the top 100 most cited articles related to ACS in adults was conducted on May 20, 2021. The Scopus database was searched to identify the top-cited articles. The following term was applied: "acute chest syndrome" in the fields of title, abstract, and keyword. The most cited article received a total of 776 citations, while the least cited received a total of 10 citations. Over half of the identified articles received 35 citations or less. The articles originated in 12 different countries; the overwhelming majority of articles originated in the United States (n = 75), with small contributions from developing countries with a high prevalence of sickle cell disease. Blood and American Journal of Hematology published the largest number of articles, with nine articles each. The Author "Vichinsky, E.P." has the largest contribution with a total of 10 articles. The plethora of the highly cited articles were Observational studies, while randomized controlled trials were represented by seven articles. The present study demonstrates that research in ACS may be receiving less attention than it should. Therefore, research empowerment and adequate funding are of paramount importance to improve research productivity and quality. Additionally, more collaborative efforts should be encouraged to reduce the gap between developed and developing countries.

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, α2β2) 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 β-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 β-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.

Vaso-occlusive crisis pain intensity, frequency, and duration: which best correlates with health-related quality of life in adolescents and adults with sickle cell disease?

ABSTRACT

In a cross-sectional analysis of baseline data from a randomized clinical trial, we studied 198 adolescents and adults aged 15+ with sickle cell disease. Interest was in assessing the relative strengths of the relationship of vaso-occlusive crisis (VOC) pain domains of intensity, frequency, and duration, with health-related quality of life (HRQOL). Variation in psychosocial, physical function, and pain expression domains of HRQOL was partially explained by frequency, intensity, and duration of VOC pain, separately and together, over and above differences in age, sex, genotype, and organ system damage. However, no single domain measure accounted for more than an additional partial R2 of 12.5% alone. Vaso-occlusive crisis pain frequency explained the most variation, when simultaneously considering VOC intensity and duration, except for stiffness , where duration was most predictive. Yet VOC pain intensity, and even VOC duration, also contributed to variability in HRQOL. We recommend that for most purposes, because all 3 VOC pain domains contribute to variability in HRQOL, all 3 domains should be assessed and interventions should be targeted to improve all 3 domains to maximize HRQOL outcomes (Clinical Trial Registration: ClinicalTrials.gov Identifier: NCT02197845 ).

Bach1 inhibitor HPP-D mediates γ-globin gene activation in sickle erythroid progenitors

Sickle cell disease (SCD) is the most common β-hemoglobinopathy caused by various mutations in the adult β-globin gene resulting in sickle hemoglobin production, chronic hemolytic anemia, pain, and progressive organ damage. The best therapeutic strategies to manage the clinical symptoms of SCD is the induction of fetal hemoglobin (HbF) using chemical agents. At present, among the Food and Drug Administration-approved drugs to treat SCD, hydroxyurea is the only one proven to induce HbF protein synthesis, however, it is not effective in all people. Therefore, we evaluated the ability of the novel Bach1 inhibitor, HPP-D to induce HbF in KU812 cells and primary sickle erythroid progenitors. HPP-D increased HbF and decreased Bach1 protein levels in both cell types. Furthermore, chromatin immunoprecipitation assay showed reduced Bach1 and increased NRF2 binding to the γ-globin promoter antioxidant response elements. We also observed increased levels of the active histone marks H3K4Me1 and H3K4Me3 supporting an open chromatin configuration. In primary sickle erythroid progenitors, HPP-D increased γ-globin transcription and HbF positive cells and reduced sickled erythroid progenitors under hypoxia conditions. Collectively, our data demonstrate that HPP-D induces γ-globin gene transcription through Bach1 inhibition and enhanced NRF2 binding in the γ-globin promoter antioxidant response elements.

Biopsychosocial Factors Associated With Pain and Pain-Related Outcomes in Adults and Children With Sickle Cell Disease: A Multivariable Analysis of the GRNDaD Multicenter Registry

Pain is the primary symptomatic manifestation of sickle cell disease (SCD), an inherited hemoglobinopathy. The characteristics that influence pain experiences and outcomes in SCD are not fully understood. The primary objective of this study was to use multivariable modeling to examine associations of biopsychosocial variables with a disease-specific measure of pain interference known as pain impact. We conducted a secondary analysis of data from the Global Research Network for Data and Discovery national SCD registry. A total of 657 children and adults with SCD were included in the analysis. This sample was 60% female with a median age of 34 (interquartile range 26-42 years) and a chronic pain prevalence of 64%. The model accounted for 58% of the variance in pain impact. Low social (P < .001) and emotional (P < .001) functioning, increasing age (P = .004), low income (P < .001), and high acute painful episodes (P = .007) were most strongly associated with high pain impact in our multivariable model. Additionally, multivariable modeling of pain severity and physical function in 2 comparable samples of registry participants revealed that increasing age and low social functioning were also strongly associated with higher pain severity and low physical functioning. Overall, the results suggest that social and emotional functioning are more strongly associated with pain impact in individuals with SCD than previously studied biological modifiers such as SCD genotype, hemoglobin, and percentage fetal hemoglobin. Future research using longitudinally collected data is needed to confirm these findings. PERSPECTIVE: This study reveals that psychosocial (ie, social and emotional functioning) and demographic (ie, age) variables may play an important role in predicting pain and pain-related outcomes in SCD. Our findings can inform future multicenter prospective longitudinal studies aimed at identifying modifiable psychosocial predictors of adverse pain outcomes in SCD.

A mass spectrometry assay for detection of endogenous and lentiviral engineered hemoglobin in cultured cells and sickle cell disease mice

Sickle cell disease (SCD) results from a sequence defect in the β-globin chain of adult hemoglobin (HbA) leading to expression of sickle hemoglobin (HbS). It is traditionally diagnosed by cellulose-acetate hemoglobin electrophoresis or high-performance liquid chromatography. While clinically useful, these methods have both sensitivity and specificity limitations. We developed a novel mass spectrometry (MS) method for the rapid, sensitive and highly quantitative detection of endogenous human β-globin and sickle hβ-globin, as well as lentiviral-encoded therapeutic hβAS3-globin in cultured cells and small quantities of mouse peripheral blood. The MS methods were used to phenotype homozygous HbA (AA), heterozygous HbA-HbS (AS) and homozygous HbS (SS) Townes SCD mice and detect lentiviral vector-encoded hβAS3-globin in transduced mouse erythroid cell cultures and transduced human CD34+ cells after erythroid differentiation. hβAS3-globin was also detected in peripheral blood 6 weeks post-transplant of transduced Townes SS bone marrow cells into syngeneic Townes SS mice and persisted for over 20 weeks post-transplant. As several genome-editing and gene therapy approaches for severe hemoglobin disorders are currently in clinical trials, this MS method will be useful for patient assessment before treatment and during follow-up.

Renal outcomes in pediatric patients with sickle cell disease: a single center experience in Saudi Arabia

Background

Sickle cell nephropathy (SCN) is a significant complication of sickle cell disease (SCD) with an asymptomatic onset in childhood and potential progression to chronic kidney disease (CKD). The clinical findings of SCN include hyposthenuria, hematuria, proteinuria, hyperfiltration, and CKD. Data on renal manifestation among patients with SCD in Saudi Arabia is lacking. Therefore, this study aimed to evaluate renal outcomes in patients with SCD who visited a hematology clinic at the National Guard Hospital, Jeddah.

Methods

We conducted a retrospective chart review of renal complications in patients with SCD who are within 0-14 years of age and on regular follow-ups at the pediatric hematology clinic in King Abdulaziz Medical City-Jeddah, Saudi Arabia.

Results

Among the 140 patients with SCD, 99 met the inclusion criteria. The median age at diagnosis was 18 (1-108) months. Two SCD phenotypes were observed, with 82 (83%) patients having sickle cell anemia (HbSS) and 17 (17%) having HbS/B+ thalassemia. Of the total patients, 92 (93%) were administered hydroxyurea (HU), with a median starting age of 48 (9-168) months. The most common renal complication observed during routine urinalysis was hematuria (38%), followed by proteinuria (11%). After stratifying the sample into four age groups (0-3 years old, 4-7 years old, 8-11 years old, and 12-14 years old), the mean glomerular filtration rate (GFR) values were 96.16, 101.36, 112.69, and 120.11 ml/min/1.73 m2 respectively. Renal imaging revealed abnormal findings in 27 (29%) patients. The most common abnormality observed on US was increased echogenicity (43%).

Conclusion

SCN is a significant complication of SCD. In this study, we assessed the renal outcomes in pediatric patients with SCD. After analyzing the clinical findings of SCN, we concluded that the presence of renal complications in pediatric patients presented a progressive pattern.

The challenge of clinical end points in sickle cell disease

As most patients with sickle cell disease (SCD) do not have access to curative therapies, the availability of drug therapies that can modify disease severity remains highly desirable. Despite an increased understanding of the pathophysiology of SCD, only 4 drugs are approved by the US Food and Drugs Administration. Most drug trials in SCD have involved the use of acute pain episodes as the primary clinical end point. These studies have typically been to prevent or shorten the duration of such episodes. To date, no drug has received regulatory approval for shortening the duration of acute vaso-occlusive complications, likely highlighting the complex pathophysiology of acute pain episodes. Trials to prevent acute pain episodes have largely evaluated those episodes requiring health care use as a surrogate end point. However, with differences in culture and health care practices among countries, health care use may not reliably predict clinically important effects on acute pain episodes. This article discusses issues related to the use of health care use as the primary end point for prevention trials of acute pain episodes and highlights the importance of evaluating patient-reported outcomes as well as other SCD-related complications as outcome measures.

miR-365-3p mediates BCL11A and SOX6 erythroid-specific coregulation: A new player in HbF activation

Hemoglobin switching is a complex biological process not yet fully elucidated. The mechanism regulating the suppression of fetal hemoglobin (HbF) expression is of particular interest because of the positive impact of HbF on the course of diseases such as β-thalassemia and sickle cell disease, hereditary hemoglobin disorders that affect the health of countless individuals worldwide. Several transcription factors have been implicated in the control of HbF, of which BCL11A has emerged as a major player in HbF silencing. SOX6 has also been implicated in silencing HbF and is critical to the silencing of the mouse embryonic hemoglobins. BCL11A and SOX6 are co-expressed and physically interact in the erythroid compartment during differentiation. In this study, we observe that BCL11A knockout leads to post-transcriptional downregulation of SOX6 through activation of microRNA (miR)-365-3p. Downregulating SOX6 by transient ectopic expression of miR-365-3p or gene editing activates embryonic and fetal β-like globin gene expression in erythroid cells. The synchronized expression of BCL11A and SOX6 is crucial for hemoglobin switching. In this study, we identified a BCL11A/miR-365-3p/SOX6 evolutionarily conserved pathway, providing insights into the regulation of the embryonic and fetal globin genes suggesting new targets for treating β-hemoglobinopathies.

Using disease-modifying therapies in sickle cell disease

As curative therapy using allogeneic hematopoietic stem cell transplantation as well as gene therapy and gene editing remains inaccessible to most patients with sickle cell disease, the availability of drug therapies that are safe, efficacious, and affordable is highly desirable. Increasing progress is being made in developing drug therapies based on our understanding of disease pathophysiology. Four drugs, hydroxyurea, L-glutamine, crizanlizumab, and voxelotor, are currently approved by the US Food and Drug Administration, with multiple others at various stages of testing. With the limited efficacy of individual agents, combinations of agents will likely be required for optimal outcomes.

Overview of the Association Between the Pathophysiology, Types, and Management of Sickle Cell Disease and Stroke

Sickle cell disease (SCD) is a genetic blood disorder that affects hemoglobin and increases stroke risk, particularly in childhood. This review examines the pathophysiological association between SCD and stroke, the classification of stroke types, risk factors, diagnosis, management, prevention, and prognosis. A comprehensive literature search was conducted via PubMed, Scopus, and Cochrane databases. Relevant studies on SCD and stroke pathophysiology, classification, epidemiology, diagnosis, treatment, and prevention were identified. Sickle cell disease causes red blood cells to become rigid and sickle-shaped, obstructing blood vessels. Recurrent sickling alters cerebral blood flow and damages vessel walls, often leading to ischemic or hemorrhagic strokes (HS). These occur most frequently in childhood, with ischemic strokes (IS) being more common. Key risk factors include a prior transient ischemic attack (TIA), low hemoglobin, and a high leukocyte count. Neuroimaging is essential for diagnosis and determining stroke type. Primary prevention centers on blood transfusions and hydroxyurea for those at high risk. Acute treatment involves promptly restoring blood flow and managing complications. However, significant knowledge gaps remain regarding stroke mechanisms, optimizing screening protocols, and improving long-term outcomes. This review synthesizes current evidence on SCD and stroke to highlight opportunities for further research and standardizing care protocols across institutions. Ultimately, a holistic perspective is critical for mitigating the high risk of debilitating strokes in this vulnerable patient population.

Illness Intrusiveness in Adults with Sickle Cell Disease: The Role of Fatigue

Chronic illness experiences often interfere with daily functioning (a concept known as illness intrusiveness) and health-related quality of life (HRQoL). However, less is known about the role of specific symptoms in predicting illness intrusiveness in sickle cell disease (SCD). This exploratory study examined associations between common SCD-related symptoms (i.e., pain, fatigue, depression, and anxiety), illness intrusiveness, and HRQoL among adults with SCD (n = 60). Illness intrusiveness significantly correlated with fatigue severity (r = .39, p = .002), depression severity (r = .45, p < .001), anxiety severity (r = .41, p = .001), physical HRQoL (r = - .53, p < .001), and mental HRQoL (r = - .44, p < .001). Multiple regression revealed a significant overall model, (R2 = .28, F(4, 55) = 5.21, p = .001), with fatigue, but not pain, depression, or anxiety, significantly predicting illness intrusiveness (β = .29, p = .036). Results suggest that fatigue may be a primary factor contributing to illness intrusiveness-a determinant of HRQoL-in individuals with SCD. Given the limited sample size, larger confirmatory studies are warranted.

Fatty acid nitroalkenes - Multi-target agents for the treatment of sickle cell disease

Sickle cell disease (SCD) is a hereditary hematological disease with high morbidity and mortality rates worldwide. Despite being monogenic, SCD patients display a plethora of disease-associated complications including anemia, oxidative stress, sterile inflammation, vaso-occlusive crisis-related pain, and vasculopathy, all of which contribute to multiorgan dysfunction and failure. Over the past decade, numerous small molecule drugs, biologics, and gene-based interventions have been evaluated; however, only four disease-modifying drug therapies are presently FDA approved. Barriers regarding effectiveness, accessibility, affordability, tolerance, and compliance of the current polypharmacy-based disease-management approaches are challenging. As such, there is an unmet pharmacological need for safer, more efficacious, and logistically accessible treatment options for SCD patients. Herein, we evaluate the potential of small molecule nitroalkenes such as nitro-fatty acid (NO2-FA) as a therapy for SCD. These agents are electrophilic and exert anti-inflammatory and tissue repair effects through an ability to transiently post-translationally bind to and modify transcription factors, pro-inflammatory enzymes and cell signaling mediators. Preclinical and clinical studies affirm safety of the drug class and a murine model of SCD reveals protection against inflammation, fibrosis, and vascular dysfunction. Despite protective cardiac, renal, pulmonary, and central nervous system effects of nitroalkenes, they have not previously been considered as therapy for SCD. We highlight the pathways targeted by this drug class, which can potentially prevent the end-organ damage associated with SCD and contrast their prospective therapeutic benefits for SCD as opposed to current polypharmacy approaches.

Pain Frequency and Health Care Utilization Patterns in Women with Sickle Cell Disease Experiencing Menstruation-Associated Pain Crises

Background: Pain crises in sickle cell disease (SCD) lead to high rates of health care utilization. Historically, women have reported higher pain burdens than men, with recent studies showing a temporal association between pain crisis and menstruation. However, health care utilization patterns of SCD women with menstruation-associated pain crises have not been reported. We studied the frequency, severity, and health care utilization of menstruation-associated pain crises in SCD women. Materials and Methods: A multinational, cross-sectional cohort study of the SCD phenotype was executed using a validated questionnaire and medical chart review from the Consortium for the Advancement of Sickle Cell Research (CASiRe) cohort. Total number of pain crises, emergency room/day hospital visits, and hospitalizations were collected from a subcohort of 178 SCD women within the past 6 months and previous year. Results: Thirty-nine percent of women reported menstruation-associated pain crises in their lifetime. These women were significantly more likely to be hospitalized compared with those who did not (mean 1.70 vs. 0.67, p = 0.0005). Women reporting menstruation-associated pain crises in the past 6 months also experienced increased hospitalizations compared with those who did not (mean 1.71 vs. 0.75, p = 0.0016). Forty percent of women reported at least four menstruation-associated pain crises in the past 6 months. Conclusions: Nearly 40% of SCD women have menstruation-associated pain crises. Menstruation-associated pain crises are associated with high pain burden and increased rates of hospitalization. Strategies are needed to address health care disparities within gynecologic care in SCD.

Prevalence and Impact of HMOX1 Polymorphism (rs2071746: A > T) in Indian Sickle Cell Disease Patients

Introduction  Fetal hemoglobin (HbF) levels play significant role in lowering down the morbidity and mortality in sickle cell disease (SCD) patients. Coinheritance of heme oxygenase-1 (HMOX1) rs2071746:A > T polymorphism may contribute to variable HbF levels in Indian SCD patients. Objective  This study was aimed to evaluate the role of HMOX1 polymorphism and its impact on HbF level in Indian SCD patients. Materials and Methods  One-hundred twenty confirmed cases of SCD and 50 healthy controls were recruited. Their mean age was 11.5 ± 8.6 years (range: 3-23 years). Quantification of Hb, HbA2, HbF, and HbS was done by capillary zone electrophoresis. Allele-specific polymerase chain reaction was used to genotype HMOX1 (rs2071746:A > T) gene polymorphism. Results  Out of the 120 cases of SCD, 65 were hemoglobin sickle-shaped (HbSS) and 55 were sickle-beta thalassemia (Sβ). Out of 65 HbSS patients, 29 (44.6%) were heterozygous (AT), 20 (30.76%) were homozygous (TT), and 16 (24.61%) were found wild-type (AA) genotype. Out of 55 Sβ, 22 (40%) were heterozygous, 18 (32%) were homozygous and 15 (28%) were wild-type. Patients carrying HMOX1 (rs2071746:A > T), AT, and TT genotypes had less anemia, painful crisis, splenomegaly, hepatomegaly, jaundice, and blood transfusion. HbF level was found higher in TT genotype (in HbSS the HbF levels was 25.1 ± 4.4; in sickle-beta thalassemia the HbF levels was 36.1 ± 4.7) than wild-type(AA) and was statistically significant ( p -value <0.001). Conclusion  The TT genotype of the rs2071746:A > T polymorphism was associated with increased levels of Hb F ( p  < 0.001). It can serve as a HbF modifier in Indian sickle cell diseases patients.

Provider prescription of hydroxyurea in youth and adults with sickle cell disease: A review of prescription barriers and facilitators

Sickle cell disease (SCD) is an inherited red blood cell disorder associated with frequent painful events and organ damage. Hydroxyurea (HU) is the recommended evidence-based treatment of SCD. However, among patients eligible for HU, prescription rates are low. Utilizing a scoping review approach, we summarized and synthesized relevant findings regarding provider barriers and facilitators to the prescription of HU in youth and adults with SCD and provided suggestions for future implementation strategies to improve prescription rates. Relevant databases were searched using specified search terms. Articles reporting provider barriers and/or facilitators to prescribing HU were included. A total of 10 studies met the inclusion criteria. Common barriers to the prescription of HU identified by providers included: doubts around patients' adherence to HU and their engaging in required testing, concerns about side effects, lack of knowledge, cost and patient concerns about side effects. Facilitators to the prescription of HU included beliefs in the effectiveness of HU, provider demographics and knowledge. Findings suggest significant provider biases exist, particularly in the form of negative perceptions towards patients' ability to adhere to taking HU and engaging in the required follow-up. Improving provider knowledge and attitudes towards HU and SCD may help improve low prescription rates.

VWF-ADAMTS13 axis dysfunction in children with sickle cell disease treated with hydroxycarbamide vs blood transfusion

Previous studies have reported elevated von Willebrand factor (VWF) levels in patients with sickle cell disease (SCD) and demonstrated a key role for the VWF-ADAMTS13 axis in the pathobiology of SCD vaso-occlusion. Although blood transfusion is the gold standard for stroke prevention in SCD, the biological mechanisms underpinning its improved efficacy compared with hydroxycarbamide are not fully understood. We hypothesized that the improved efficacy of blood transfusion might relate to differences in VWF-ADAMTS13 axis dysfunction. In total, 180 children with a confirmed diagnosis of SCD (hemoglobin SS) on hydroxycarbamide (n = 96) or blood transfusion (n = 84) were included. Despite disease-modifying treatment, plasma VWF and VWF propeptide were elevated in a significant proportion of children with SCD (33% and 47%, respectively). Crucially, all VWF parameters were significantly higher in the hydroxycarbamide compared with the blood transfusion cohort (P < .05). Additionally, increased levels of other Weibel-Palade body-stored proteins, including factor VIII (FVIII), angiopoietin-2, and osteoprotegerin were observed, indicated ongoing endothelial cell activation. Children treated with hydroxycarbamide also had higher FVIII activity and enhanced thrombin generation compared with those in the blood transfusion cohort (P < .001). Finally, hemolysis markers strongly correlated with VWF levels (P < .001) and were significantly reduced in the blood transfusion cohort (P < .001). Cumulatively, to our knowledge, our findings demonstrate for the first time that despite treatment, ongoing dysfunction of the VWF-ADAMTS13 axis is present in a significant subgroup of pediatric patients with SCD, especially those treated with hydroxycarbamide.

Associating a standardized reporting tool for chest radiographs with clinical complications in pediatric acute chest syndrome

BACKGROUND

Acute chest syndrome (ACS) is an important cause of morbidity in sickle cell disease (SCD). A standardized tool for reporting chest radiographs in pediatric SCD patients did not previously exist.

OBJECTIVE

To analyze the interobserver agreement among pediatric radiologists' interpretations for pediatric ACS chest radiographs utilizing a standardized reporting tool. We also explored the association of radiographic findings with ACS complications.

METHODS

This was a retrospective cohort study of pediatric ACS admissions from a single institution in 2019. ICD-10 codes identified 127 ACS admissions. Two radiologists independently interpreted the chest radiographs utilizing a standardized reporting tool, a third radiologist adjudicated discrepancies, and κ analysis assessed interobserver agreement. Clinical outcomes were correlated with chest radiograph findings utilizing Pearsons' χ2 , t tests, and Mann-Whitney U tests. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated.

RESULTS

Interobserver agreement was moderate to near-perfect across variables, with κ analysis showing near-perfect agreement for opacity reported in the right upper lobe (0.84), substantial agreement for right lower lobe (0.63), and vertebral bony changes (0.72), with moderate agreement for all other reported variables. On the initial chest radiograph, an opacity located in the left lower lobe (LLL) correlated with pediatric intensive care unit transfer (p = .03). Pleural effusion on the initial chest radiograph had a 3.98 OR (95% CI: 1.35-11.74) of requiring blood products and a 10.67 OR (95% CI: 3.62-31.39) for noninvasive ventilation.

CONCLUSION

The standardized reporting tool showed moderate to near-perfect agreement between radiologists. LLL opacity, and pleural effusion were associated with increased risk of ACS complications.

Sickle cell disease classification using deep learning

This paper presents a transfer and deep learning based approach to the classification of Sickle Cell Disease (SCD). Five transfer learning models such as ResNet-50, AlexNet, MobileNet, VGG-16 and VGG-19, and a sequential convolutional neural network (CNN) have been implemented for SCD classification. ErythrocytesIDB dataset has been used for training and testing the models. In order to make up for the data insufficiency of the erythrocytesIDB dataset, advanced image augmentation techniques are employed to ensure the robustness of the dataset, enhance dataset diversity and improve the accuracy of the models. An ablation experiment using Random Forest and Support Vector Machine (SVM) classifiers along with various hyperparameter tweaking was carried out to determine the contribution of different model elements on their predicted accuracy. A rigorous statistical analysis was carried out for evaluation and to further evaluate the model's robustness, an adversarial attack test was conducted. The experimental results demonstrate compelling performance across all models. After performing the statistical tests, it was observed that MobileNet showed a significant improvement (p = 0.0229), while other models (ResNet-50, AlexNet, VGG-16, VGG-19) did not (p > 0.05). Notably, the ResNet-50 model achieves remarkable precision, recall, and F1-score values of 100 % for circular, elongated, and other cell shapes when experimented with a smaller dataset. The AlexNet model achieves a balanced precision (98 %) and recall (99 %) for circular and elongated shapes. Meanwhile, the other models showcase competitive performance.

Males with sickle cell disease have higher risks of cerebrovascular disease, increased inflammation, and a reduced response to hydroxyurea

Biological sex is important. Male sex is associated with worse outcomes in most measures, including cerebrovascular disease, hospital admissions, and blood transfusions, but not survival. Females also appear to have a better response to hydroxyurea therapy, reduced markers of inflammation, and better liver function.

Exploration de l’hémolyse associée à la drépanocytose et perspectives thérapeutiques spécifiques

Sickle Cell Anemia is a disease with a strong vascular tropism. Beyond anemia, the pathophysiological mechanisms responsible for hemolysis, directly affect both acute and chronic vascular damages, thus resulting in a systemic disease. Understanding the different types of hemolysis underline the need for novel specific biomarkers. Targeted therapeutic approaches for these pathophysiological pathways are necessary to improve Sickle Cell patients' prognosis. Finally, given its complexity, Sickle Cell Disease is often used as a "proof of concept" for other pathologies. It seems likely that the rapidly evolving knowledge in this field will also benefit other diseases. © 2023 Société nationale française de médecine interne (SNFMI). Published by Elsevier Masson SAS. All rights reserved.

Combining PTCy and ATG for GvHD prophylaxis in non-malignant diseases

Bone marrow transplantation for non-malignant diseases such as aplastic anemia and hemoglobinopathies is a burgeoning clinical area. The goal of these transplants is to correct the hematopoietic defect with as little toxicity as possible. This requires mitigation of transplant-specific toxicities such as graft versus host disease, given this is not needed in non-malignant disorders. This review details current clinical outcomes in the field with a focus on post-transplantation cyclophosphamide and anti-thymoglobulin as intensive graft versus host disease prophylaxis to achieve that goal.

Successes and challenges in clinical gene therapy

Despite the ups and downs in the field over three decades, the science of gene therapy has continued to advance and provide enduring treatments for increasing number of diseases. There are active clinical trials approaching a variety of inherited and acquired disorders of different organ systems. Approaches include ex vivo modification of hematologic stem cells (HSC), T lymphocytes and other immune cells, as well as in vivo delivery of genes or gene editing reagents to the relevant target cells by either local or systemic administration. In this article, we highlight success and ongoing challenges in three areas of high activity in gene therapy: inherited blood cell diseases by targeting hematopoietic stem cells, malignant disorders using immune effector cells genetically modified with chimeric antigen receptors, and ophthalmologic, neurologic, and coagulation disorders using in vivo administration of adeno-associated virus (AAV) vectors. In recent years, there have been true cures for many of these diseases, with sustained clinical benefit that exceed those from other medical approaches. Each of these treatments faces ongoing challenges, namely their high one-time costs and the complexity of manufacturing the therapeutic agents, which are biological viruses and cell products, at pharmacologic standards of quality and consistency. New models of reimbursement are needed to make these innovative treatments widely available to patients in need.

Differential clinical characteristics across traditional Chinese medicine (TCM) syndromes in patients with sickle cell disease

Background

Pain is a common, debilitating, and poorly understood complication of sickle cell disease (SCD). The need for clinical pain management of SCD is largely unmet and relies on opioids as the main therapeutic option, which leads to a decreased quality of life (QoL). According to the literature, acupuncture has shown certain therapeutic effects for pain management in SCD. However, these clinical studies lack the guidance of Traditional Chinese Medicine (TCM) Syndrome Differentiation principles for treatment.

Aim

To characterize differences in clinical presentation amongst TCM-diagnosed syndromes in SCD patients.

Method

52 patients with SCD and 28 age- and sex-matched healthy controls (HCs) were enrolled in an ongoing trial of acupuncture. Each participant completed a series of questionnaires on pain, physical function, fatigue, sleep, anxiety, depression, and QoL and underwent cold- and pressure-based quantitative sensory testing at baseline. Data on prescription opioid use over the 12 months prior to study enrollment was used to calculate mean daily morphine milligram equivalents (MME). Differences among the three TCM syndromes were analyzed by one-way ANOVA followed by Tukey post hoc testing. Two-sample t-tests were used to compare SCD and HC groups.

Results

TCM diagnosis criteria classified SCD patients into one of three TCM syndromes: a) Equal; b) Deficiency; and c) Stagnation. The Stagnation group exhibited higher pain interference, physical dysfunction, nociplastic pain, fatigue, anxiety, depression, MME consumption, and lower sleep quality and QoL compared to the Equal group. Few differences were observed between HCs and the Equal SCD group across outcomes. Deficiency and Stagnation groups were differentiated with observed- and patient-reported clinical manifestations.

Conclusion

These findings suggest that TCM-diagnosed syndromes in SCD can be differentially characterized using validated objective and patient-reported outcomes. Because characteristics of pain and co-morbidities in each SCD patient are unique, targeting specific TCM "syndromes" may facilitate treatment effectiveness with a syndrome-based personalized treatment plan that conforms to TCM principles. These findings lay the foundation for the development of tailored acupuncture interventions based on TCM syndromes for managing pain in SCD. Larger samples are required to further refine and validate TCM diagnostic criteria for SCD.

Understanding multi-level barriers to medication adherence among adults living with sickle cell disease

There is limited research that identifies and examines multi-level barriers to medication adherence among adults with Sickle Cell Disease (SCD); Identify multi-level barriers to medication adherence among adults with SCD; and Examine the relationship between multi-level barriers and medication adherence levels. A cross-sectional study included 130 adults (ages ≥ 18 years old) living with SCD who receive treatment/care from one of the 10 adult SCD clinics within the Networking California for sickle cell care initiative. Study measures included the medication adherence report scale (Professor Rob Horne), Beliefs about Medicine Questionnaire (Professor Rob Horne), and patient reported outcomes measurement information system. Participants reported barriers to medication adherence across 3 levels: Community-level barriers (e.g., COVID-19 pandemic); Institutional-level barriers (e.g., bad experiences with the health care system); and Individual-level barriers (e.g., beliefs and depression severity). Depression severity and patient concerns about SCD medication were inversely correlated with medication adherence (rs = -0.302, P < .001; rs = -0.341, P < .001 respectively). Patient beliefs about the necessity of SCD medication were insignificantly correlated with medication adherence (rs = 0.065, P = .464). Medication adherence was higher among patients who had fewer adherence barriers than multiple adherence barriers (Median medication adherence: fewer barriers = 22 vs multiple barrier = 20.50, P = .085), suggesting clinical significance although statistically insignificant. Identifying multi-level adherence barriers and examining their relationship with medication adherence will help develop targeted public health strategies to promote improved medication adherence and wellness among adults with SCD.

Genetic Variation and Sickle Cell Disease Severity: A Systematic Review and Meta-Analysis

Importance

Sickle cell disease (SCD) is a monogenic disorder, yet clinical outcomes are influenced by additional genetic factors. Despite decades of research, the genetics of SCD remain poorly understood.

Objective

To assess all reported genetic modifiers of SCD, evaluate the design of associated studies, and provide guidelines for future analyses according to modern genetic study recommendations.

Data Sources

PubMed, Web of Science, and Scopus were searched through May 16, 2023, identifying 5290 publications.

Study Selection

At least 2 reviewers identified 571 original, peer-reviewed English-language publications reporting genetic modifiers of human SCD phenotypes, wherein the outcome was not treatment response, and the comparison was not between SCD subtypes or including healthy controls.

Data Extraction and Synthesis

Data relevant to all genetic modifiers of SCD were extracted, evaluated, and presented following STREGA and PRISMA guidelines. Weighted z score meta-analyses and pathway analyses were conducted.

Main Outcomes and Measures

Outcomes were aggregated into 25 categories, grouped as acute complications, chronic conditions, hematologic parameters or biomarkers, and general or mixed measures of SCD severity.

Results

The 571 included studies reported on 29 670 unique individuals (50% ≤ 18 years of age) from 43 countries. Of the 17 757 extracted results (4890 significant) in 1552 genes, 3675 results met the study criteria for meta-analysis: reported phenotype and genotype, association size and direction, variability measure, sample size, and statistical test. Only 173 results for 62 associations could be cross-study combined. The remaining associations could not be aggregated because they were only reported once or methods (eg, study design, reporting practice) and genotype or phenotype definitions were insufficiently harmonized. Gene variants regulating fetal hemoglobin and α-thalassemia (important markers for SCD severity) were frequently identified: 19 single-nucleotide variants in BCL11A, HBS1L-MYB, and HBG2 were significantly associated with fetal hemoglobin (absolute value of Z = 4.00 to 20.66; P = 8.63 × 10-95 to 6.19 × 10-5), and α-thalassemia deletions were significantly associated with increased hemoglobin level and reduced risk of albuminuria, abnormal transcranial Doppler velocity, and stroke (absolute value of Z = 3.43 to 5.16; P = 2.42 × 10-7 to 6.00 × 10-4). However, other associations remain unconfirmed. Pathway analyses of significant genes highlighted the importance of cellular adhesion, inflammation, oxidative and toxic stress, and blood vessel regulation in SCD (23 of the top 25 Gene Ontology pathways involve these processes) and suggested future research areas.

Conclusions and Relevance

The findings of this comprehensive systematic review and meta-analysis of all published genetic modifiers of SCD indicated that implementation of standardized phenotypes, statistical methods, and reporting practices should accelerate discovery and validation of genetic modifiers and development of clinically actionable genetic profiles.

Pain management in adult patients with sickle cell disease in the emergency department: how does current practice compare with existing standards of care?

PURPOSE

Sickle cell disease (SCD) is an inherited blood disorder with a natural course punctuated by acute complications including painful vaso-occlusive episodes. The objectives were: (1) to determine what proportion of patients with SCD receive opioids within 30 min of triage as recommended by the current clinical recommendations and quality standard; and (2) to identify facilitators to timely opioid administration for patients with SCD.

METHODS

This was a retrospective observational study. The primary outcome was the proportion of visits in which patients received opioid analgesia within 30 min of triage. Secondary outcomes were time in minutes from triage to any analgesic administration and time from triage to first opioid administration. Patient demographics and ED encounter characteristics were included as potential associated variables.

RESULTS

There were 236 patient visits (by 103 patients) that met inclusion criteria. Patients received opioid analgesia within 30 min of triage in only 5.2% of visits. The median time from triage to opioid analgesia was 80 (IQR = 49.0, 125.5) minutes. Using an order set and receiving opioid analgesia prior to physician assessment were both associated with shorter times to opioid analgesia.

CONCLUSION

Existing recommendations are that opioid analgesia be provided within 30 min of triage for patients with SCD and VOEs. Our data show this target is rarely met, even in a department in which SCD VOEs are a common presenting concern. The association of earlier opioid analgesia with order set use and administration prior to physician assessment highlights potential avenues for improving time to analgesia.

Understanding Sickle cell disease: Causes, symptoms, and treatment options

Sickle cell disease (SCD) is a hereditary blood disorder characterized by the production of abnormal hemoglobin molecules that cause red blood cells to take on a crescent or sickle shape. This condition affects millions of people worldwide, particularly those of African, Mediterranean, Middle Eastern, and South Asian descent. This paper aims to provide an overview of SCD by exploring its causes, symptoms, and available treatment options. The primary cause of SCD is a mutation in the gene responsible for producing hemoglobin, the protein that carries oxygen in red blood cells. This mutation has abnormal hemoglobin called hemoglobin S, which causes red blood cells to become stiff and sticky, leading to various health complications. Patients with SCD may experience recurrent pain, fatigue, anemia, and increased infection susceptibility. Treatment options for SCD focus on managing symptoms and preventing complications. This includes pain management with analgesics, hydration, and blood transfusions to improve oxygen delivery. Hydroxyurea, a medication that increases the production of fetal hemoglobin, is commonly used to reduce the frequency and severity of pain crises. Additionally, bone marrow or stem cell transplants can cure select individuals with severe SCD. Finally, understanding the causes, symptoms, and treatment options for SCD is crucial for healthcare professionals, patients, and their families. It enables early diagnosis, effective symptom management, and improved quality of life for individuals with this chronic condition.

Genetic reversal of the globin switch concurrently modulates both fetal and sickle hemoglobin and reduces red cell sickling

We previously reported initial clinical results of post-transcriptional gene silencing of BCL11A expression (NCT03282656) reversing the fetal to adult hemoglobin switch. A goal of this approach is to increase fetal hemoglobin (HbF) expression while coordinately reducing sickle hemoglobin (HbS) expression. The resulting combinatorial effect should prove effective in inhibiting HbS polymerization at lower physiologic oxygen values thereby mitigating disease complications. Here we report results of exploratory single-cell analysis of patients in which BCL11A is targeted molecularly and compare results with cells of patients treated with hydroxyurea (HU), the current standard of care. We use single-cell assays to assess HbF, HbS, oxygen saturation, and hemoglobin polymer content in RBCs for nine gene therapy trial subjects (BCLshmiR, median HbF% = 27.9) and compare them to 10 HU-treated subjects demonstrating high and comparable levels of HbF (HU High Responders, median HbF% = 27.0). All BCL11A patients achieved the primary endpoint for NCT03282656, which was defined by an absolute neutrophil count greater than or equal to 0.5 × 109 cells/L for three consecutive days, achieved within 7 weeks following infusion. Flow cytometric assessment of single-RBC HbF and HbS shows fewer RBCs with high HbS% that would be most susceptible to sickling in BCLshmiR vs. HU High Responders: median 42% of RBCs with HbS%>70% in BCLshmiR vs. 61% in HU High Responders (p = 0.004). BCLshmiR subjects also demonstrate more RBCs resistant to HbS polymerization at lower physiologic oxygen tension: median 32% vs. 25% in HU High Responders (p = 0.006). Gene therapy-induced BCL11A down-regulation reverses the fetal-to-adult hemoglobin switch and induces RBCs with higher HbF%, lower HbS%, and greater resistance to deoxygenation-induced polymerization in clinical trial subjects compared with a cohort of highly responsive hydroxyurea-treated subjects.

Single nucleotide polymorphisms and sickle cell disease-related pain: a systematic review

Background

Scientists have speculated genetic variants may contribute to an individual's unique pain experience. Although research exists regarding the relationship between single nucleotide polymorphisms and sickle cell disease-related pain, this literature has not been synthesized to help inform future precision health research for sickle cell disease-related pain. Our primary aim of this systematic review was to synthesize the current state of scientific literature regarding single nucleotide polymorphisms and their association with sickle cell disease-related pain.

Methods

Using the Prisma guidelines, we conducted our search between December 2021-April 2022. We searched PubMed, Web of Science, CINAHL, and Embase databases (1998-2022) and selected all peer-reviewed articles that included reports of associations between single nucleotide polymorphisms and sickle cell disease-related pain outcomes.

Results

Our search yielded 215 articles, 80 of which were duplicates, and after two reviewers (GG, JD) independently screened the 135 non-duplicate articles, we retained 22 articles that met the study criteria. The synthesis of internationally generated evidence revealed that this scientific area remains predominantly exploratory in nature, with only three studies reporting sufficient power for genetic association. Sampling varied across studies with a range of children to older adults with SCD. All of the included articles (n = 22) examined acute pain, while only nine of those studies also examined chronic pain.

Conclusion

Currently, the evidence implicating genetic variation contributing to acute and chronic sickle cell disease-related pain is characterized by modestly powered candidate-gene studies using rigorous SCD-pain outcomes. Effect sizes and directions vary across studies and are valuable for informing the design of future studies. Further research is needed to replicate these associations and extend findings with hypothesis-driven research to inform precision health research.

Evaluating the impact of sickle cell disease on COVID-19 susceptibility and severity: a retrospective cohort study based on electronic health record

Background

Sickle cell trait/disease (SCT/SCD) are enriched among Black people and associated with various comorbidities. The overrepresentation of these characteristics prevents traditional regression approach obtaining convincing evidence for the independent effect of SCT/SCD on other health outcomes. This study aims to investigate the association between SCT/SCD and COVID-19-related outcomes using causal inference approaches that balance the covariate.

Methods

We leveraged electronic health record (EHR) data from the University of Chicago Medicine between March 2020 and December 2021. Demographic characteristics were retrieved. Medical conditions were identified using ICD-10 codes. Five approaches, including two traditional regression approaches (unadjusted and adjusted) and three causal inference approaches [covariate balancing propensity score (CBPS) matching, CBPS weighting, and CBPS adjustment], were employed.

Results

A total of 112,334 patients were included in the study, among which 504 had SCT and 388 SCD. Patients with SCT/SCD were more likely to be non-Hispanic Black people, younger, female, non-smokers, and had a diagnosis of diabetes, heart failure, asthma, and cerebral infarction. Causal inference approaches achieved a balanced distribution of these covariates while traditional approaches failed. Across these approaches, SCD was consistently associated with COVID-19-related pneumonia (odds ratios (OR) estimates, 3.23 (95% CI: 2.13-4.89) to 2.57 (95% CI: 1.10-6.00)) and pain (OR estimates, 6.51 (95% CI: 4.68-9.06) to 2.47 (95% CI: 1.35-4.49)). While CBPS matching suggested an association between SCD and COVID-19-related acute respiratory distress syndrome (OR = 2.01, 95% CI: 0.97-4.17), this association was significant in other approaches (OR estimates, 2.96 (95% CI: 1.69-5.18) to 2.50 (95% CI: 1.43-4.37)). No association was observed between SCT and COVID-19-related outcomes in causal inference approaches.

Conclusion

Using causal inference approaches, we provide comprehensive evidence for the link between SCT/SCD and COVID-19-related outcomes.

Genome-wide meta-analysis identifies new candidate genes for sickle cell disease nephropathy

Sickle cell disease nephropathy (SCDN), a common SCD complication, is strongly associated with mortality. Polygenic risk scores calculated from recent transethnic meta-analyses of urinary albumin-to-creatinine ratio and estimated glomerular filtration rate (eGFR) trended toward association with proteinuria and eGFR in SCD but the model fit was poor (R2 < 0.01), suggesting that there are likely unique genetic risk factors for SCDN. Therefore, we performed genome-wide association studies (GWAS) for 2 critical manifestations of SCDN, proteinuria and decreased eGFR, in 2 well-characterized adult SCD cohorts, representing, to the best of our knowledge, the largest SCDN sample to date. Meta-analysis identified 6 genome-wide significant associations (false discovery rate, q ≤ 0.05): 3 for proteinuria (CRYL1, VWF, and ADAMTS7) and 3 for eGFR (LRP1B, linc02288, and FPGT-TNNI3K/TNNI3K). These associations are independent of APOL1 risk and represent novel SCDN loci, many with evidence for regulatory function. Moreover, GWAS SNPs in CRYL1, VWF, ADAMTS7, and linc02288 are associated with gene expression in kidney and pathways important to both renal function and SCD biology, supporting the hypothesis that SCDN pathophysiology is distinct from other forms of kidney disease. Together, these findings provide new targets for functional follow-up that could be tested prospectively and potentially used to identify patients with SCD who are at risk, before onset of kidney dysfunction.

Pharmacokinetics and pharmacodynamics of an oral formulation of decitabine and tetrahydrouridine

BACKGROUND

Sickle cell disease (SCD) is caused by an inherited structural abnormality of adult hemoglobin causing polymerization. Fetal hemoglobin interferes with polymerization but is epigenetically silenced by DNA methyltransferase 1 (DNMT1) in adult erythropoiesis. Decitabine depletes DNMT1 and increases fetal and total hemoglobin in SCD patients, but is rapidly catabolized by cytidine deaminase (CDA) in vivo. Tetrahydrouridine (THU) inhibits CDA, safeguarding decitabine.

METHODS

The pharmacokinetics and pharmacodynamics of three oral combination formulations of THU and decitabine, with different coatings producing different delays in decitabine release, were investigated in healthy participants.

RESULTS

Tetrahydrouridine and decitabine were rapidly absorbed into the systemic circulation after a single combination oral dose, with relative bioavailability of decitabine ≥74% in fasted males compared with separate oral administration of THU followed by decitabine 1 h later. THU and decitabine Cmax and area under the plasma concentration versus time curve were higher in females versus males, and fasted versus fed states. Despite sex and food effect on pharmacokinetics, the pharmacodynamic effect of DNMT1 downregulation was comparable in males and females and fasted and fed states. Treatments were well tolerated.

CONCLUSION

Combination oral formulations of THU with decitabine produced pharmacokinetics and pharmacodynamics suitable for oral DNMT1-targeted therapy.

Sex and frequency of pain episodes are associated with acute pain trajectories in adolescents with sickle cell disease

Introduction/Objective

Acute pain episodes are a major cause of health care utilization (HCU) in sickle cell disease (SCD), and adolescence is associated with increased pain frequency. We sought to determine whether there were differences in acute pain trajectories by sex and frequency of pain episodes among adolescents with SCD who presented to the emergency department (ED).

Methods

Retrospective review of electronic health records from a large, multicampus, pediatric SCD program.

Results

Of the 113 adolescents included, the mean age was 16.6 (SD 0.9), 41.6% (n = 47) were female, 77.9% (n = 88) had HbSS or a similarly severe genotype, and 43.4% (n = 49) had ≥3 episodes of HCU for pain, which we defined as having history of high HCU for pain. Those with a history of high HCU for pain had higher mean pain intensity scores at presentation, were more likely to receive either intravenous or intranasal opioids, and were more likely to be hospitalized. In a model considering the 3-way interaction between sex, history of high HCU for pain, and follow-up time from the initial pain intensity score, adjusted for opioid per kilogram body weight, and prescription of hydroxyurea, adolescent female patients with high HCU for pain had the slowest decline in pain intensity during treatment for acute pain in the ED.

Conclusion

Sex and history of high HCU for pain are associated with acute pain trajectories in adolescents with SCD presenting to the ED. These novel findings should be confirmed in future prospective studies.

Nitrite decreases sickle hemoglobin polymerization in vitro independently of methemoglobin formation

The root cause of sickle cell disease (SCD) is the polymerization of sickle hemoglobin (HbS) leading to sickling of red blood cells (RBC). Earlier studies showed that in patients with SCD, high-dose nitrite inhibited sickling, an effect originally attributed to HbS oxidation to methemoglobin-S even though the anti-sickling effect did not correlate with methemoglobin-S levels. Here, we examined the effects of nitrite on HbS polymerization and on methemoglobin formation in a SCD mouse model. In vitro, at concentrations higher than physiologic (>1 μM), nitrite increased the delay time for polymerization of deoxygenated HbS independently of methemoglobin-S formation, which only occurred at much higher concentrations (>300 μM). In vitro, higher nitrite concentrations oxidized 100% of normal hemoglobin A (HbA), but only 70% of HbS. Dimethyl adipimidate, an anti-polymerization agent, increased the fraction of HbS oxidized by nitrite to 82%, suggesting that polymerized HbS partially contributed to the oxidation-resistant fraction of HbS. At low concentrations (10 μM-1 mM), nitrite did not increase the formation of reactive oxygen species but at high concentrations (10 mM) it decreased sickle RBC viability. In SCD mice, 4-week administration of nitrite yielded no significant changes in methemoglobin or nitrite levels in plasma and RBC, however, it further increased leukocytosis. Overall, these data suggest that nitrite at supra-physiologic concentrations has anti-polymerization properties in vitro and that leukocytosis is a potential nitrite toxicity in vivo. Therefore, to determine whether the anti-polymerization effect of nitrite observed in vitro underlies the decreases in sickling observed in patients with SCD, administration of higher nitrite doses is required.

Combinatorial targeting of epigenome-modifying enzymes with decitabine and RN-1 synergistically increases HbF

Increased fetal hemoglobin (HbF) levels reduce the symptoms of sickle cell disease (SCD) and increase the lifespan of patients. Because curative strategies for bone marrow transplantation and gene therapy technologies remain unavailable to a large number of patients, the development of a safe and effective pharmacological therapy that increases HbF offers the greatest potential for disease intervention. Although hydroxyurea increases HbF, a substantial proportion of patients fail to demonstrate an adequate response. Pharmacological inhibitors of DNA methyltransferase (DNMT1) and lysine-specific demethylase 1A (LSD1), 2 epigenome-modifying enzymes associated with the multiprotein corepressor complex recruited to the repressed γ-globin gene, are powerful in vivo inducers of HbF. The hematological side effects of these inhibitors limit feasible clinical exposures. We evaluated whether administering these drugs in combination could reduce the dose and/or time of exposure to any single agent to minimize adverse effects, while achieving additive or synergistic increases in HbF. The DNMT1 inhibitor decitabine (0.5 mg/kg per day) and the LSD1 inhibitor RN-1 (0.25 mg/kg per day) administered in combination 2 days per week produced synergistic increases in F-cells, F-reticulocytes, and γ-globin messenger RNA in healthy baboons. Large increases in HbF and F-cells were observed in healthy, nonanemic, and anemic (phlebotomized) baboons. Combinatorial therapy targeting epigenome-modifying enzymes could thus be a useful strategy for producing larger increases in HbF to modify the clinical course of SCD.

Cognition and education benefits of increased hemoglobin and blood oxygenation in children with sickle cell disease

BACKGROUND

Among individuals with sickle cell disease (SCD), decreased hemoglobin is associated with lower oxygen saturation (SpO2) and increased risk of stroke, both of which are associated with lower intelligence quotient (IQ) scores. Thus, increasing hemoglobin and SpO2 in individuals with SCD may increase IQ and educational attainment.

METHODS

A cohort simulation model was built to determine academic performance and educational attainment based on cognitive function (measured by IQ) of a pediatric SCD cohort randomly assigned to treatment and control groups. The model contained two key stages: childhood (<10 years) and adolescence (≥10 years). In stage 1, increased hemoglobin and increased SpO2 (assigned to the treatment group) were determinants of higher IQ, prevention of IQ deterioration over time. Increased hemoglobin was also a determinant of decreased stroke risk. In stage 2, improvement in adolescent IQ as a result of treatment was a determinant of academic performance.

RESULTS

In a simulated cohort of 2000 children and adolescents with SCD (52.5% female, 50% treated), stroke incidence was predicted to be 44.4% lower among the treated group than the untreated group (4.5% versus 8.1%, respectively). The average IQ among the treated group was estimated to be 91.1 compared with 82.9 in the untreated group (a 9.9% difference; P<0.001). Finally, high school (≥12 years of education) completion rates were estimated to be 64.7% higher among the treated group: 76.1% of the treated group was projected to complete high school compared with 46.2% of the untreated group.

CONCLUSIONS

Our model predicts that an average improvement in hemoglobin of 1.1 g/dL (11 g/L) among individuals with SCD may be associated with improved neurocognition and educational outcomes. These improvements may also generate benefits not captured by our model, including improved quality of life, employment, and income.

Defining global strategies to improve outcomes in sickle cell disease: a Lancet Haematology Commission

All over the world, people with sickle cell disease (an inherited condition) have premature deaths and preventable severe chronic complications, which considerably affect their quality of life, career progression, and financial status. In addition, these people are often affected by stigmatisation or structural racism, which can contribute to stress and poor mental health. Inequalities affecting people with sickle cell disease are also reflected in the distribution of the disease—mainly in sub-Saharan Africa, India, and the Caribbean—whereas interventions, clinical trials, and funding are mostly available in North America, Europe, and the Middle East. Although some of these characteristics also affect people with other genetic diseases, the fate of people with sickle cell disease seems to be particularly unfair. Simple, effective interventions to reduce the mortality and morbidity associated with sickle cell disease are available. The main obstacle preventing better outcomes in this condition, which is a neglected disease, is associated with inequalities impacting the patient populations. The aim of this Commission is to highlight the problems associated with sickle cell disease and to identify achievable goals to improve outcomes both in the short and long term.

The ambition for the management of people with sickle cell disease is that curative treatments become available to every person with the condition. Although this would have seemed unrealistic a decade ago, developments in gene therapy make this potentially achievable, albeit in the distant future. Until these curative technologies are fully developed and become widely available, health-care professionals (with the support of policy makers, funders, etc) should make sure that a minimum standard of care (including screening, prophylaxis against infection, acute medical care, safe blood transfusion, and hydroxyurea) is available to all patients.

In considering what needs to be achieved to reduce the global burden of sickle cell disease and improve the quality of life of patients, this Commission focuses on five key areas: the epidemiology of sickle cell disease (Section 1 ); screening and prevention (Section 2 ); established and emerging treatments for the management of the disease (Section 3 ); cellular therapies with curative potential (Section 4 ); and training and education needs (Section 5 ). As clinicians, researchers, and patients, our objective to reduce the global burden of sickle cell disease aligns with wider public health aims to reduce inequalities, improve health for all, and develop personalised treatment options. We have observed in the past few years some long-awaited momentum following the development of innovative point-of-care testing devices, new approved drugs, and emerging curative options. Reducing the burden of sickle cell disease will require substantial financial and political commitment, but it will impact the lives of millions of patients and families worldwide and the lessons learned in achieving this goal would unarguably benefit society as a whole.

Preliminary construct validity of patient-reported outcomes to assess chronic pain in adults with sickle cell disease

Chronic pain affects 30% to 40% of individuals with sickle cell disease (SCD) and impairs patient functioning. Clinically meaningful, practical, and valid assessment tools for investigation, evaluation, and management of chronic pain are limited, representing a barrier for advancing SCD care. We sought to determine whether patient-reported outcomes (PROs) show preliminary construct validity in identifying individuals with SCD who were a priori defined as suggestive of having chronic pain based on previously published criteria. All individuals completed the Patient-Reported Outcomes Measurement Information System (PROMIS) domains: pain interference, pain behavior, pain quality (nociceptive, neuropathic), fatigue, sleep disturbance, depression, and anxiety; the Adult Sickle Cell Quality of Life Measurement Information System (ASCQ-Me) domains: pain impact and emotional impact; and the painDETECT questionnaire. Thirty-three adults living with SCD were enrolled, and 42.4% had chronic pain. Pain-related PROs scores distinctly differentiated individuals with chronic pain from those without. Individuals with chronic pain had significantly worse pain-related PROs scores: PROMIS pain interference (64.2 vs 54.3), PROMIS pain behavior (63.2 vs 50), and ASCQ-Me pain impact (42.9 vs 53.2). According to published PROMIS clinical cut scores for the pain-related domains, individuals with chronic pain were categorized as having moderate impairment, whereas those without chronic pain had mild or no impairment. Individuals with chronic pain had PRO pain features consistent with neuropathic pain and worse scores in fatigue, depression, sleep disturbance, and emotional impact. Pain-related PROs show preliminary construct validity in differentiating individuals with and without chronic SCD pain and could be used as valuable tools for research and clinical monitoring of chronic pain.

Long-term survival with sickle cell disease: a nationwide cohort study of Medicare and Medicaid beneficiaries

To our knowledge, we report the first population-based period life table, the expected lifetime survival for Medicare and Medicaid beneficiaries with sickle cell disease (SCD), and the disparities in survival by insurance types in the United States. We constructed a retrospective cohort of individuals with diagnosed SCD receiving common care (any real-world patterns of care except transplant) based on nationwide Medicare and Medicaid claim data (2008-2016), covering beneficiaries in all 50 states. We analyzed lifetime survival probabilities using Kaplan-Meier curves and projected life expectancies at various ages for all, stratified by sex and insurance types. Our analysis included 94 616 individuals with SCD that have not undergone any transplant. Life expectancy at birth was 52.6 years (95% confidence interval: 51.9-53.4). Compared with the adults covered by Medicaid only, those covered by Medicare for disabilities or end-stage renal disease and those dually insured by Medicare and Medicaid had significantly worse life expectancy. Similarly, for beneficiaries aged ≥65 years, these 2 insurance types were associated with significantly shorter life expectancy than those enrolled in Medicare old age and survivor's insurance. Our study underscores the persistent life expectancy shortfall for patients with SCD, the burden of premature mortality during adulthood, and survival disparities by insurance status.

A Challenging Case of Severe Sickle Cell Crisis With Multiorgan Involvement: A Case Report

Sickle cell anemia is a chronic and debilitating hemoglobinopathy characterized by the presence of abnormal hemoglobin, resulting in the formation of sickle-shaped red blood cells. This case report presents an unusual case of a 32-year-old female patient with sickle cell anemia who had not experienced any previous sickle cell crises since her diagnosis at the age of four years. Despite a stable clinical history, the patient's condition rapidly deteriorated, leading to septic shock, multiorgan failure, and atypical complications such as neurological impairment and acute kidney injury. Intensive management strategies, including blood exchange, mechanical ventilation, and aggressive antibiotic therapy, were implemented but unfortunately failed to reverse the progressive clinical deterioration. This case underscores the importance of early recognition and a multidisciplinary approach in managing atypical sickle cell crises to optimize patient outcomes. Further research is needed to improve our understanding and management of such presentations.

Emerging Therapies and Advances in Sickle Cell Disease with a Focus on Renal Manifestations

The underlying mechanisms of disease in sickle cell disease (SCD) contribute to a multifaceted nephropathy, commonly manifested as albuminuria. In severe SCD genotypes ( e.g. , Hemoglobin SS [HbSS]), albuminuria and CKD are major predictors of mortality in this population. Therefore, the monitoring and management of renal function is an intrinsic part of comprehensive care in SCD. Management of nephropathy in SCD can be accomplished with SCD-directed therapies and/or CKD-directed therapies. In the past 5 years, novel disease-modifying and palliative therapies have been approved in SCD to target aspects of the disease, such as anemia, inflammation, and vasculopathy. Along with conventional hydroxyurea and chronic transfusion, l -glutamine, crizanlizumab, and voxelotor have all been shown to mitigate some adverse effect of SCD, and their effect on nephropathy is being investigated. CKD-directed therapies such as renin-angiotensin-aldosterone system blockers have long been used in SCD nephropathy; however, more complete long-term studies on benefits are needed. Given the effect of renal disease on survival, further assessment of the mechanisms and efficacy of these SCD-directed or CKD-directed therapeutic agents is essential.

Parental perspective on the risk of infertility and fertility preservation options for children and adolescents with sickle cell disease considering hematopoietic stem cell transplantation

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (HCT) performed in children from human leukocyte antigen (HLA)-identical related donors is associated with very high survival rates and disease-free survival. Patients are exposed to gonadotoxic alkylating agents or irradiation in the HCT conditioning regimen. Consequently, infertility is a major long-term complication of HCT for sickle cell disease (SCD). We sought to understand how caregivers perceive the risk of infertility from HCT, how they perceive the options for fertility preservation, and how this risk perception impacted their decision-making to pursue HCT.

PROCEDURES

We conducted qualitative interviews with primary caregivers after a consultation for HCT for SCD. Data were analyzed using descriptive qualitative analysis.

RESULTS

We interviewed 19 primary caregivers who had attended a consultation with an HCT physician (female, age 25-59 [median 39] years). Eleven participants reported that their child had an available HLA-matched donor. Analysis revealed that (i) mothers were worried about death and graft-versus-host disease from HCT, more than about the risk of infertility; (ii) parents have a realistic understanding of the risk of infertility after HCT and take it into consideration in decision-making; (iii) parents report multiple barriers to fertility preservation.

CONCLUSION

For parents actively considering HCT for their child with SCD, the risk of infertility while important was not a barrier to pursuing HCT. Inconvenience and invasiveness of fertility preservation procedures are some of the barriers to pursuing fertility preservation for their child. Future research must aim at addressing these barriers to fertility preservation.