Acute care utilization among individuals with sickle cell disease and related cardiopulmonary and renal complications.

Cardiopulmonary and renal end organ (CPR) complications are associated with early mortality among individuals with sickle cell disease (SCD). However, there is limited knowledge regarding acute care utilization for individuals with SCD and CPR complications. Our objective was to determine the prevalence of CPR complications in a state specific SCD population and compare acute care utilization among individuals with and without CPR complications. We leveraged 2017-2020 data for individuals with SCD identified by the Sickle Cell Data Collection program in Wisconsin. The prevalence of CPR complications is determined for distinct age groups. Generalized linear models adjusted for age compared the rate of acute care visits/person/year among individuals who had cardiopulmonary only, renal only, both cardiopulmonary and renal, or no CPR complications. There were 1378 individuals with SCD, 52% females, mean (SD) age 28.3 (18.5) years; 48% had at least one CPR complication during the study period. The prevalence of CPR complications was higher in adults (69%) compared to pediatric (15%) and transition (51%) groups. Individuals with SCD and cardiopulmonary complications had higher acute visit rates than those without CPR complications (5.4 (IQR 5.0-5.8) vs 2.4 (IQR 2.1-2.5), p <0.001)). Acute care visit rates were similar between individuals with SCD who had renal only complications and no CPR complications (2.7 (IQR 2.5-3.0) vs 2.4 (2.1-2.5), p = 0.24). The high acute care visit rates, especially for those with cardiopulmonary complications, warrant further investigation to understand risk factors for CPR complications, the underlying reasons and identify effective disease management strategies.

Isoquercetin for thromboinflammation in sickle cell disease: a randomized double-blind placebo-controlled trial.

ABSTRACT: Data from a small trial in patients with cancer suggest that isoquercetin (IQ) treatment lowered thrombosis biomarkers and prevented clinical thrombosis, but, to our knowledge, no studies of IQ have been conducted to target thromboinflammation in adults with sickle cell disease (SCD). We conducted a randomized, double-blind, placebo-controlled trial in adults with steady-state SCD (hemoglobin SS [HbSS], HbSß0thal, HbSß+thal, or HbSC). The primary outcome was the change in plasma soluble P-selectin (sP-selectin) after treatment compared with baseline, analyzed in the intention-to-treat population. Between November 2019 and July 2022, 46 patients (aged 40 ± 11 years, 56% female, 75% under hydroxyurea treatment) were randomized to receive IQ (n = 23) or placebo (n = 23). IQ was well tolerated and all the adverse events (AEs; n = 21) or serious AEs (n = 14) recorded were not attributable to the study drug. The mean posttreatment change for sP-selectin showed no significant difference between the treatment groups (IQ, 0.10 ± 6.53 vs placebo, 0.74 ± 4.54; P = .64). In patients treated with IQ, whole-blood coagulation (P = .03) and collagen-induced platelet aggregation (P = .03) were significantly reduced from the baseline. Inducible mononuclear cell tissue factor gene expression and plasma protein disulfide isomerase reductase activity were also significantly inhibited (P = .003 and P = .02, respectively). Short-term fixed-dose IQ in patients with SCD was safe with no off-target bleeding and was associated with changes from the baseline in the appropriate direction for several biomarkers of thromboinflammation. The trial was registered at www.clinicaltrials.gov as #NCT04514510.

COVID-19 and venous thromboembolism risk in patients with sickle cell disease.

Venous thromboembolism (VTE) is a life-threatening complication observed among patients with sickle cell disease (SCD) and also among those with severe COVID-19 infection. Although prior studies show that patients with SCD are at risk of severe COVID-19 illness, it remains unclear if COVID-19 infection further increases VTE risk for this population. We hypothesized that patients with SCD hospitalized for COVID-19 would have higher VTE rates than those hospitalized for other causes. Using electronic health record data from a multisite research network, TriNetX, we identified 2 groups of patients with SCD hospitalized during 2020: (1) with COVID-19 and (2) without COVID-19. We compared VTE rates using risk ratios estimated based on adjusted Poisson regression model with log link and robust error variances. Of the 281 SCD patients hospitalized with COVID-19 and 4873 SCD patients hospitalized without COVID-19 , 35 (12.46%) and 418 (8.58%) had incident VTE within 6 months of the index hospitalization respectively. After adjusting for differences in baseline characteristics, no significant differences in VTE rates within 6 months were found between the 2 groups (adjusted relative risk, 1.06 [95% confidence interval, 0.79-1.41]). These data suggest that hospitalization with COVID-19 does not further increase VTE risk in patients with SCD.

Circulating mitochondrial DNA is a proinflammatory DAMP in sickle cell disease.

The pathophysiology of sickle cell disease (SCD) is driven by chronic inflammation fueled by damage associated molecular patterns (DAMPs). We show that elevated cell-free DNA (cfDNA) in patients with SCD is not just a prognostic biomarker, it also contributes to the pathological inflammation. Within the elevated cfDNA, patients with SCD had a significantly higher ratio of cell-free mitochondrial DNA (cf-mtDNA)/cell-free nuclear DNA compared with healthy controls. Additionally, mitochondrial DNA in patient samples showed significantly disproportionately increased hypomethylation compared with healthy controls, and it was increased further in crises compared with steady-state. Using flow cytometry, structured illumination microscopy, and electron microscopy, we showed that circulating SCD red blood cells abnormally retained their mitochondria and, thus, are likely to be the source of the elevated cf-mtDNA in patients with SCD. Patient plasma containing high levels of cf-mtDNA triggered the formation of neutrophil extracellular traps (NETs) that was substantially reduced by inhibition of TANK-binding kinase 1, implicating activation of the cGAS-STING pathway. cf-mtDNA is an erythrocytic DAMP, highlighting an underappreciated role for mitochondria in sickle pathology. These trials were registered at www.clinicaltrials.gov as #NCT00081523, #NCT03049475, and #NCT00047996.

The molecular basis for the prothrombotic state in sickle cell disease.

The genetic and molecular basis of sickle cell disease (SCD) has long since been characterized but the pathophysiological basis is not entirely defined. How a red cell hemolytic disorder initiates inflammation, endothelial dysfunction, coagulation activation and eventually leads to vascular thrombosis, is yet to be elucidated. Recent evidence has demonstrated a high frequency of unprovoked/recurrent venous thromboembolism (VTE) in SCD, with an increased risk of mortality among patients with a history of VTE. Here, we thoroughly review the molecular basis for the prothrombotic state in SCD, specifically highlighting emerging evidence for activation of overlapping inflammation and coagulation pathways, that predispose to venous thromboembolism. We share perspectives in managing venous thrombosis in SCD, highlighting innovative therapies with the potential to influence the clinical course of disease and reduce thrombotic risk, while maintaining an acceptable safety profile.

Post-translational modification as a response to cellular stress induced by hemoglobin oxidation in sickle cell disease.

Intracellular oxidative stress and oxidative modification of sickle hemoglobin (HbS) play a role in sickle cell disease (SCD) pathogenesis. Recently, we reported that Hb-dependent oxidative stress induced post-translational modifications (PTMs) of Hb and red blood cell (RBC) membrane proteins of transgenic SCD mice. To identify the mechanistic basis of these protein modifications, we followed in vitro oxidative changes occurring in intracellular Hb obtained from RBCs and RBC-derived microparticles (MPs) from the blood of 23 SCD patients (HbSS) of which 11 were on, and 12, off hydroxyurea (HU) treatment, and 5 ethnic matched controls. We used mass spectrometry-based proteomics to characterize these oxidative PTMs on a cross-sectional group of these patients (n = 4) and a separate subgroup of patients (n = 2) studied prior to initiation and during HU treatment. Collectively, these data indicated that band-3 and its interaction network involved in MPs formation exhibited more protein phosphorylation and ubiquitination in SCD patients than in controls. HU treatment reversed these oxidative PTMs back to level observed in controls. These PTMs were also confirmed using orthogonal immunoprecipitation experiments. Moreover, we observed specific markers reflective of oxidative stress, including irreversible oxidation of ßCys93 and ubiquitination of Hb ßLys145 (and ßLys96). Overall, these studies strongly suggest that extensive erythrocyte membrane protein phosphorylation and ubiquitination are involved in SCD pathogenesis and provide further insight into the multifaceted effects of HU treatment.

Sickle Cell Disease: A Paradigm for Venous Thrombosis Pathophysiology.

Venous thromboembolism (VTE) is an important cause of vascular morbidity and mortality. Many risk factors have been identified for venous thrombosis that lead to alterations in blood flow, activate the vascular endothelium, and increase the propensity for blood coagulation. However, the precise molecular and cellular mechanisms that cause blood clots in the venous vasculature have not been fully elucidated. Patients with sickle cell disease (SCD) demonstrate all the risk factors for venous stasis, activated endothelium, and blood hypercoagulability, making them particularly vulnerable to VTE. In this review, we will discuss how mouse models have elucidated the complex vascular pathobiology of SCD. We review the dysregulated pathways of inflammation and coagulation in SCD and how the resultant hypercoagulable state can potentiate thrombosis through down-regulation of vascular anticoagulants. Studies of VTE pathogenesis using SCD mouse models may provide insight into the intersection between the cellular and molecular processes involving inflammation and coagulation and help to identify novel mechanistic pathways.

Effect of a Community Health Worker-Delivered Parental Education and Counseling Intervention on Anemia Cure Rates in Rural Indian Children: A Pragmatic Cluster Randomized Clinical Trial.

IMPORTANCE: Iron deficiency anemia, the largest cause of anemia worldwide, adversely affects cognitive development in children. Moreover, the imperceptible childhood anemia prevalence reduction in response to anemia control measures is associated with tremendous social and economic cost. OBJECTIVE: To evaluate the effects of community-based parental education/counseling when combined with usual treatment on children's anemia cure rate. DESIGN, SETTING, AND PARTICIPANTS: A pragmatic cluster randomized clinical trial in children aged 12 to 59 months from 55 villages from the rural Chamrajnagar district in southern India was conducted between November 2014 and July 2015; 6-month follow-up ended in January 2016. Villages were randomly assigned to either usual treatment (n = 27) or to the intervention (n = 28). Among 1144 participating children, 534 were diagnosed as having anemia (hemoglobin levels <11 g/dL and >7.9 g/dL; to convert to grams per liter, multiply by 10) and constituted the study sample in this analysis. Data were analyzed between July 2016 and September 2017. INTERVENTIONS: Iron and folic acid (IFA), 20 mg/d, 5 times daily per week, for 5 months (usual treatment) or health worker-delivered education/counseling combined with usual treatment (intervention). MAIN OUTCOMES AND MEASURES: The primary outcome was anemia cure rate defined as hemoglobin level at or greater than 11 g/dL during follow-up. RESULTS: Of the children included in the study, the mean age was 30 months, with a slightly higher ratio of boys to girls. Of 534 children with anemia (intervention n = 303; usual treatment n = 231), 517 were reassessed after 6 months (intervention n = 298; usual treatment n = 219) while 17 were lost to follow-up (intervention n = 5 and usual treatment n = 12). Anemia cure rate was higher in children in the intervention group compared with children receiving usual treatment (55.7% [n = 166 of 298] vs 41.4% [n = 90 of 219]). The risk ratio derived through multilevel logistic regression was 1.37 (95% CI, 1.04-1.70); the model-estimated risk difference was 15.1% (95% CI, 3.9-26.3). Intervention-group children demonstrated larger mean hemoglobin increments (difference, intervention vs control: 0.25 g/dL; 95% CI, 0.07-0.44 g/dL) and improved IFA adherence (61.7%; 95% CI, 56.2-67.3 vs 48.4%; 95% CI, 41.7-55.1 consumed >75% of tablets provided). Adverse events were mild (intervention: 26.8%; 95% CI, 21.8-31.9 vs usual treatment: 21%; 95% CI, 15.6-26.4). To cure 1 child with anemia, 7 mothers needed to be counseled (number needed to treat: 7; 95% CI, 4-26). CONCLUSIONS AND RELEVANCE: Parental education and counseling by a community health worker achieved perceivable gains in curing childhood anemia. Policy makers should consider this approach to enhance population level anemia control. TRIAL REGISTRATION: ISRCTN identifier: ISRCTN68413407.

A Growing Population of Older Adults with Sickle Cell Disease.

In countries with organized access to health care, survival of patients with sickle cell disease (SCD) has greatly improved, shifting the burden of care from a pediatrician to an internal medicine physician. As a consequence, cumulative disease complications related to chronic vasculopathy are becoming more apparent, adding to organ dysfunction from physiologic aging. The time has come for us to reevaluate the approach to managing the older adult with SCD by putting a greater emphasis on geriatric conditions while proactively considering curative options once previously offered only to younger patients, with comprehensive annual assessments and joint clinics with relevant specialists.

Interactions of an Anti-Sickling Drug with Hemoglobin in Red Blood Cells from a Patient with Sickle Cell Anemia.

The pathophysiology associated with sickle cell disease (SCD) includes hemolytic anemia, vaso-occlusive events, and ultimately end organ damage set off by the polymerization of deoxygenated hemoglobin S (HbS) into long fibers and sickling of red blood cells (RBCs). One approach toward mitigating HbS polymerization is to pharmacologically stabilize the oxygenated (R) conformation of HbS and thereby reduce sickling frequency and SCD pathology. GBT440 is an α-subunit-specific modifying agent that has recently been reported to increase HbS oxygen binding affinity and consequently delay in vitro polymerization. In addition, animal model studies have demonstrated the potential for GBT440 to be a suitable therapeutic for daily oral dosing in humans. Here, we report an optimized method for detecting GBT440 intermediates in human patient hemolysate using a combination of HPLC and mass spectrometry analysis. First, oxygen dissociation curves (ODCs) analyzed from patient blood showed that oxygen affinity increased in a dose dependent manner. Second, HPLC and integrated mass spectrometric analysis collectively confirmed that GBT440 labeling was specific to the α N-terminus thereby ruling out other potential ligand binding sites. Finally, the results from this optimized analytical approach allowed us to detect a stable α-specific GBT440 adduct in the patient's hemolysate in a dose dependent manner. The results and methods presented in this report could therefore potentially help therapeutic monitoring of GBT440 induced oxygen affinity and reveal critical insight into the biophysical properties of GBT440 Hb complexes.

The platelet NLRP3 inflammasome is upregulated in sickle cell disease via HMGB1/TLR4 and Bruton tyrosine kinase.

A key inflammatory mechanism recently identified in platelets involves the Nod-like receptor nucleotide-binding domain leucine-rich repeat containing protein 3 (NLRP3) and Bruton tyrosine kinase (BTK), which control activation of caspase-1 within inflammasome complexes. We investigated platelet caspase-1 activity in the context of sickle cell disease (SCD) directly in platelets isolated from SCD patients (n = 24) and indirectly by incubating platelets from healthy subjects with plasma obtained from SCD patients (n = 20), both in steady state and during an acute pain crisis (paired samples). The platelet NLRP3 inflammasome was upregulated in SCD patients under steady state conditions compared with healthy controls, and it was further upregulated when patients experienced an acute pain crisis. The results were consistent with indirect platelet assays, in which SCD plasma increased caspase-1 activity of platelets from healthy subjects in an NLRP3-dependent fashion. The damage-associated molecular pattern molecule high-mobility group box 1 (HMGB1) was elevated in plasma of SCD subjects compared with healthy controls and correlated with caspase-1 activity in platelets. Pharmacological or antibody-mediated inhibition of HMGB1, Toll-like receptor 4, and BTK interfered with sickle plasma-induced platelet caspase-1 activation. In Townes SCD mice, caspase-1 activity and aggregation of circulating platelets were elevated, which was suppressed by IV injection of an NLRP3 inhibitor and the BTK inhibitor ibrutinib. Activation of the platelet NLRP3 inflammasome in SCD may have diagnostic and therapeutic implications.

Optimizing diagnostic biomarkers of iron deficiency anemia in community-dwelling Indian women and preschool children.

The detection of iron deficiency anemia is challenged by the paucity of diagnostic tests demonstrating high sensitivity and specificity. Using two biomarkers, zinc-protoporphyrin/heme and hepcidin, we established the diagnostic cut-off values for iron deficiency anemia in preschool children and women. We randomly selected non-anemic individuals (n=190; women=90, children=100) and individuals with iron deficiency anemia (n=200; women=100, children=100) from a preexisting cohort of healthy preschool children and their mothers. The diagnostic performance of these biomarkers was estimated by analyzing receiver operating characteristic curves. Diagnostic cut-offs with a high predictive value for iron deficiency anemia were selected. Median zinc-protoporphyrin/heme and hepcidin values in non-anemic children were 49 µmol/mol heme and 42 ng/mL, respectively, and in non-anemic women these values were 66 µmol/mol heme and 17.7ng/mL, respectively. Children and women with iron deficiency anemia had higher zinc-protoporphyrin/heme ratios (children=151 µmol/mol heme and women=155 µmol/mol heme) and lower hepcidin levels (children=1.2ng/mL and women=0.6ng/mL). A zinc-protoporphyrin/heme ratio cut-off >90 µmole/mole heme in children and >107 µmole/mole heme in women was associated with a high diagnostic likelihood for iron deficiency anemia (children, likelihood ratio=20.2: women, likelihood ratio=10.8). Hepcidin cut-off values of ≤6.8ng/mL in children and ≤4.5ng/mL in women were associated with a high diagnostic likelihood for iron deficiency anemia (children, likelihood ratio=14.3: women, likelihood ratio=16.2). The reference ranges and cut-off values identified in this study provide clinicians with guidance for applying these tests to detect iron deficiency anemia. Erythrocyte zinc-protoporphyrin/heme ratio is a valid point-of-care biomarker to diagnose iron deficiency anemia.

GlycA is not a useful biomarker of inflammation in sickle cell disease.

INTRODUCTION: Sickle cell disease (SCD) is a multisystemic disorder, the pathology being driven by recurrent inflammation particularly during a vaso-occlusive crisis. GlycA, a composite measure of protein glycation, is a sensitive biomarker for disorders associated with vascular inflammation. We determined the utility of GlycA as a biomarker of inflammation in SCD. METHODS: Stored plasma samples from patients with SCD recruited to two clinical studies were analyzed. One study encompasses 488 patient samples with SCD (HbSS, HbSß0 and HbSC) at steady state and 52 race-matched, healthy controls. The other study included paired plasma samples during steady state and acute pain crisis from (HbSS) patients with SCD. Plasma GlycA was measured using a proton NMR on the Vantera® Clinical Analyzer. We performed analysis comparing patients with SCD, healthy controls, and paired samples analysis. RESULTS: The mean plasma GlycA level was lower in SCD compared with healthy controls (324.6 ± 70.4 µmol/L vs. 386.3 ± 74.6 µmol/L, P < 0.0001). Within the same patient, mean plasma GlycA during acute pain crisis was lower than steady state, although the difference was not significant (300.5 ± 36.3 µmol/L vs 314.2 ± 34.8 µmol/L, P = 0.020). Plasma GlycA correlated inversely with serum LDH (P = 0.009). CONCLUSION: GlycA is not a suitable biomarker of inflammation in SCD. We surmise that its signal is confounded by hemolysis leading to a depletion of haptoglobin, one of the major plasma proteins included in the composite NMR signal. Hemolysis is further exacerbated during an acute pain crisis, hence the lower GlycA levels in crisis compared to steady state.

How I diagnose and treat venous thromboembolism in sickle cell disease.

The incidence of venous thromboembolism (VTE) in adult patients with sickle cell disease (SCD) is high. However, overlapping features between the clinical presentation of VTE and SCD complications and a low index of suspicion for thrombosis can influence patient management decisions. VTE in SCD can therefore present management challenges to the clinical hematologist. Herein, we present 3 distinct clinical vignettes that are representative of our clinical practice with SCD patients. These vignettes are discussed with specific reference to the hypercoagulable state in SCD patients, recent VTE diagnosis and anticoagulant therapy guidelines from the general population, and evaluation of the risk of bleeding as a result of long-term exposure to anticoagulant therapy. We examine current diagnostic and treatment options, highlight limitations of the existing clinical prognostic models that offer personalized guidance regarding the duration of anticoagulation, and propose a clinical approach to guide the decision to extend anticoagulation beyond 3 months.

Lay health workers perceptions of an anemia control intervention in Karnataka, India: a qualitative study.

BACKGROUND: Lay health workers (LHWs) are increasingly used to complement health services internationally. Their perceptions of the interventions they implement and their experiences in delivering community based interventions in India have been infrequently studied. We developed a novel LHW led intervention to improve anemia cure rates in rural community dwelling children attending village day care centers in South India. Since the intervention is delivered by the village day care center LHW, we sought to understand participating LHWs' acceptance of and perspectives regarding the intervention, particularly in relation to factors affecting daily implementation. METHODS: We conducted a qualitative study alongside a cluster randomized controlled trial evaluating a complex community intervention for childhood anemia control in Karnataka, South India. Focus group discussions (FGDs) were conducted with trained LHWs assigned to deliver the educational intervention. These were complemented by non-participant observations of LHWs delivering the intervention. Transcripts of the FGDs were translated and analyzed using the framework analysis method. RESULTS: Several factors made the intervention acceptable to the LHWs and facilitated its implementation including pre-implementation training modules, intervention simplicity, and ability to incorporate the intervention into the routine work schedule. LHWs felt that the intervention impacted negatively on their preexisting workload. Fluctuating relationships with mothers weakened the LHWs position as providers of the intervention and hampered efficient implementation, despite the LHWs' highly valued position in the community. Modifiable barriers to the successful implementation of this intervention were seen at two levels. At a broader contextual level, hindering factors included the LHW being overburdened, inadequately reimbursed, and receiving insufficient employer support. At the health system level, lack of streamlining of LHW duties, inability of LHWs to diagnose anemia and temporary shortfalls in the availability of iron supplements constituted potentially modifiable barriers. CONCLUSION: This qualitative study identified some of the practical challenges as experienced by LHWs while delivering a community health intervention in India. Methodologically, it highlights the value of qualitative research in understanding implementation of complex community interventions. On the contextual level, the results indicate that efficient delivery of community interventions will require streamlining of LHW workloads and improved health system infrastructure support. TRIAL REGISTRATION: This trial was registered with ISRCTN.com (identifier: ISRCTN68413407 ) on 23 September 2013.