Sex-based differences in the manifestations and complications of sickle cell disease: Report from the Sickle Cell Disease Implementation Consortium

Persistent albuminuria and chronic kidney disease in adults with sickle cell anaemia: Results from a multicenter natural history study

Clinical and laboratory correlates of chronic kidney disease (CKD) in sickle cell anaemia remain incompletely defined. In a multicenter cohort study, we evaluated the prevalence of persistent albuminuria (PA) and characteristics associated with PA, albumin-creatinine ratio (ACR) and decreased estimated glomerular filtration rate (eGFR) using logistic, linear and multinomial regression models, respectively. Of 269 participants (median age: 30 years; 57.2% females), the prevalence of PA was 35.7%. Using baseline ACR values of <100 and ≥100 mg/g, the probabilities of PA were 30.0% and 94.6%, respectively. In multivariable logistic regression analyses, male sex (β = 0.80 [SE = 0.36], p = 0.024) and ACE inhibitors/ARBs use (β = 1.54 [SE = 0.43], p < 0.001) were associated with higher likelihoods of PA, while higher haemoglobin (β = -0.33 [SE = 0.13], p = 0.009) and HbF (β = -0.04 [SE = 0.02], p = 0.041) were associated with lower likelihoods of PA. In multivariable multinomial regression analyses, older age (β = 0.06 [SE = 0.02], p = 0.004) and higher alkaline phosphatase (β = 0.01 [SE = 0.00], p = 0.004) were associated with higher odds of having eGFR 60-90 versus eGFR>90 mL/min/1.73 m2 using the cystatin C-based CKD-EPI-2012 equation. Additionally, higher systolic blood pressure (β = 0.11 [SE = 0.03], p = 0.001) and blood urea nitrogen (β = 0.45 [SE = 0.12], p < 0.001) were associated with higher odds, while higher haemoglobin (β = -1.22 [SE = 0.43], p = 0.004) was associated with lower odds of having eGFR<60 versus eGFR>90 mL/min/1.73 m2. PA and decreased eGFR are associated with measures of disease severity and comorbid conditions (Clinicaltrials.gov Identifier: NCT03277547).

Short-term air pollution levels and sickle cell disease hospital encounters in South Carolina: A case-crossover analysis

BACKGROUND

Sickle cell disease (SCD) is a genetic disorder and symptoms may be sensitive to environmental stressors. Although it has been hypothesized that exposure to outdoor air pollution could trigger acute SCD events, evidence is limited.

METHODS

We obtained SCD administrative data on hospital encounters in South Carolina from 2002 to 2019. We estimated outdoor air pollutant (particulate matter<2.5 μm (PM2.5), ozone (O3), and PM2.5 elemental carbon (EC) concentrations at residential zip codes using spatio-temporal models. Using a random bi-directional, fixed-interval case-crossover study design, we investigated the relationship between air pollution exposure over 1-, 3-, 5-, 9-, and14-day periods with SCD hospital encounters.

RESULTS

We studied 8410 patients with 144,129 hospital encounters. We did not observe associations among all patients with SCD and adults for PM2.5, O3, and EC. We observed positive associations among children for 9- and 14-day EC (OR: 1.05 (95% confidence interval (CI): 1.02, 1.08) and OR: 1.05 (95% CI: 1.02, 1.09), respectively) and 9- and 14-day O3 (OR: 1.04 (95%CI: 1.00, 1.08)) for both.

CONCLUSIONS

Our findings suggest that short-term (within two-weeks) levels of EC and O3 and may be associated with SCD hospital encounters among children. Two-pollutant model results suggest that EC is more likely responsible for effects on SCD than O3. More research is needed to confirm our findings.

Effects of hydroxyurea on fertility in male and female sickle cell disease patients. A systemic review and meta-analysis

BACKGROUND

Evidence supports the benefits of hydroxyurea (HU) in adults with sickle cell disease (SCD), but reservations remain due to long-term concerns of fertility. Retrospective analysis of clinical records of SCD patients (haemoglobin SS genotype) have identified gender-related differences in disease progression. This could inform risk stratification during SCD at diagnosis with the possibility to guide therapeutic decisions.

METHODS

This systemic review and meta-analysis evaluated fertility parameters in both children (aged ≥ 6 years) and adults with SCD receiving HU therapy. Studies were sourced from PubMed and EMBASE from inception to July 2023. A total of 160 potentially relevant articles were identified.

RESULTS

Four studies were included that evaluated the effects of HU on sperm parameters in males. A further 4 studies assessed anti-mullerian hormone (AMH) levels and ovarian reserves in females. Differences from baseline values were used to identify compromised fertility. Amongst males, HU treatment negatively impacted the concentration of spermatozoa (MD = -15.48 million/mL; 95% CI: [-20.69, -10.26]; p< 0.001), which continued following treatment cessation (MD = -20.09 million/mL; 95% CI: [-38.78, -1.40]; P = 0.04). HU treatment also led to lower total sperm counts (MD = -105.87 million; 95% CI: [-140.61, -71.13]; P< 0.001) which persisted after treatment (MD = -53.05 million; 95% CI: [-104.96, -1.14]; P = 0.05). Sperm volume, initial forward motility and morphology were unaffected by HU treatment. In females, HU treatment decreased the mean AMH levels 1.83 (95% CI [1.42, 2.56]. A total of 18.2.% patients treated with HU showed reduced ovarian reserves.

INTERPRETATION & CONCLUSIONS

This systemic review and meta-analysis suggest that the use of HU for SCD impacts seminal fluid parameters in males and can diminish AMH levels and ovarian reserves in females.

Predictors of health-related quality of life in a large cohort of adult patients living with sickle cell disease in France: the DREPAtient study

Background

Sickle cell disease (SCD) is an inherited autosomal recessive disorder exhibiting a range of symptoms and acute and/or chronic complications that affect the quality of life. This study aimed to assess health-related quality of life (HRQoL) and to identify the associated factors in adult patients with SCD in France.

Methods

DREPAtient is a cross-sectional, multicenter study conducted from June 2020 to April 2021 in France and in certain French overseas territories where SCD is highly prevalent. Sociodemographic and clinical data were collected online. HRQoL was assessed by the French version of the 36-Item Short Form Survey (SF-36) questionnaire. HRQoL determinants were identified using multivariable linear regression analysis.

Results

In total, 570 participants were included, mostly women (68.9%), with a mean age of 33.3 (±10.7) years. The highest mean score HRQoL was found in the Physical functioning domain (67.5 ± 21.8) and the lowest mean score in the General Health perception domain (37.7 ± 20.3). The mean score of the physical composite (PCS) and mental composite (MCS) of SF-36 summary scores was 40.6 ± 8.9 and 45.3 ± 9.8, respectively. Participants receiving oxygen therapy (β = -3.20 [95%CI: -5.56; -0.85]), those with a history of femoral osteonecrosis (-3.09 [-4.64; -1.53]), those hospitalized for vaso-occlusive crisis (VOC) or acute chest syndrome (ACS) (-2.58 [-3.93; -1.22]), those with chronic complications (-2.33 [-4.04; -0.62]), female participants (-2.17 [-3.65; -0.69]), those with psychological follow-up (-2.13 [-3.59; -0.67]), older participants (-1.69 [-3.28; -0.09]), and those receiving painkillers (-1.61 [-3.16; -0.06]) reported worse PCS score. By contrast, those who had completed secondary or high school (4.36 [2.41; 6.31]) and those with stable financial situation (2.85 [0.94, 4.76]) reported better PCS scores. Worse MCS scores were reported among participants with psychological follow-up (-2.54 [-4.28; -0.80]) and those hospitalized for VOC/ACS in the last 12 months (-2.38 [-3.99; -0.77]), while those who had relatives' support (5.27 [1.92; 8.62]) and those with stable financial situation (4.95 [2.65; 7.26]) reported better MCS scores.

Conclusion

Adults with major SCD reported poor physical and mental HRQoL scores. Hospitalization for VOC/ACS, chronic complications, use of painkillers, perceived financial situation, and support from relatives are important predictors of HRQoL in SCD patients. Interventions to improve HRQoL outcomes SCD should be considered.

Sickle cell disease iPSC-derived sensory neurons exhibit increased excitability and sensitization to patient plasma

ABSTRACT

Individuals living with sickle cell disease (SCD) experience severe recurrent acute and chronic pain. Challenges to gaining mechanistic insight into pathogenic SCD pain processes include differential gene expression and function of sensory neurons between humans and mice with SCD, and extremely limited availability of neuronal tissues from patients with SCD. Here, we used induced pluripotent stem cells (iPSCs), derived from patients with SCD, differentiated into sensory neurons (SCD iSNs) to begin to overcome these challenges. We characterize key gene expression and function of SCD iSNs to establish a model to investigate intrinsic and extrinsic factors that may contribute to SCD pain. Despite similarities in receptor gene expression, SCD iSNs show pronounced excitability using patch clamp electrophysiology. Furthermore, we find that plasma taken from patients with SCD during acute pain associated with a vaso-occlusive event increases the calcium responses to the nociceptive stimulus capsaicin in SCD iSNs compared with those treated with paired plasma from patients with SCD at steady state baseline or healthy control plasma samples. We identified high levels of the polyamine spermine in baseline and acute pain states of plasma from patients with SCD, which sensitizes SCD iSNs to subthreshold concentrations of capsaicin. Together, these data identify potential intrinsic mechanisms within SCD iSNs that may extend beyond a blood-based pathology.

Acute soft head syndrome in a teenager with sickle cell anemia: A case report

Key Clinical Message

Sickle cell disease (SCD) rarely presents with acute soft head syndrome (ASHS) often posing a diagnostic dilemma. Recovery is typically spontaneous, however, in the context of lack of awareness and limited brain imaging it could potentially lead to poor outcome.

Abstract

ASHS is a rare complication of SCD, invariably occurring near puberty with hitherto elusive pathogenic mechanisms. ASHS often resolves spontaneously on conservative management, however, lack of awareness in the context of limited access to brain imaging could pose diagnostic challenges resulting in inappropriate management and untoward outcome. We present a case of a teenager who presented with subtle symptoms for which the diagnosis of sickle cell anemia (SCA) was delayed until he developed ASHS. LTM was a 16 years old boy with a history of recurrent joints pain since the age of 6 years, with a family history of SCA, but had initial negative sickling test. He presented with episodes of multiple joints pain, unprovoked scalp and left orbital swelling, low-grade fever and mild headache without any evidence for bleeding diathesis. The diagnosis of SCA was confirmed by hemoglobin electrophoresis. Computed tomography (CT) scan of the head revealed subgaleal heamatoma (SGH) and intraorbital haematoma without intracranial hemorrhage (ICH). He was managed conservatively with analgesics and hydration together with antibiotics for associated sepsis with complete resolution of clinical symptoms within 2 weeks. This case represents a rare scenario for a relatively mild SCA phenotype presenting with ASHS whose diagnosis poses an enigma in the resource-limited contex. It is therefore, prudent to recognize ASHS to avoid judicious interventions which could potentially result in untoward clinical outcome.

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.

Pathophysiological characterization of the Townes mouse model for sickle cell disease

A deeper pathophysiologic understanding of available mouse models of sickle cell disease (SCD), such as the Townes model, will help improve preclinical studies. We evaluated groups of Townes mice expressing either normal adult human hemoglobin (HbA), sickle cell trait (HbAS), or SCD (HbS), comparing younger versus older adults, and females versus males. We obtained hematologic parameters in steady-state and hypoxic conditions and evaluated metabolic markers and cytokines from serum. Kidney function was evaluated by measuring the urine protein/creatinine ratio and urine osmolality. In vivo studies included von Frey assay, non-invasive plethysmography, and echocardiography. Histopathological evaluations were performed in lung, liver, spleen, and kidney tissues. HbS mice displayed elevated hemolysis markers and white blood cell counts, with some increases more pronounced in older adults. After extended in vivo hypoxia, hemoglobin, platelet counts, and white blood cell counts decreased significantly in HbS mice, whereas they remained stable in HbA mice. Cytokine analyses showed increased TNF-alpha in HbS mice. Kidney function assays revealed worsened kidney function in HbS mice. The von Frey assay showed a lower threshold to response in the HbS mice than controls, with more noticeable differences in males. Echocardiography in HbS mice suggested left ventricular hypertrophy and dilatation. Plethysmography suggested obstructive lung disease and inflammatory changes in HbS mice. Histopathological studies showed vascular congestion, increased iron deposition, and disruption of normal tissue architecture in HbS mice. These data correlate with clinical manifestations in SCD patients and highlight analyses and groups to be included in preclinical therapeutic studies.

Nutritional Heart Disease and Cardiomyopathies: JACC Focus Seminar 4/4

This JACC Focus Seminar provides an overview of and highlights recently published research on cardiomyopathies and nutritional heart disease that have a higher prevalence in tropical regions. The development of tropical cardiomyopathies and nutritional cardiovascular disease (CVD) is complicated by high rates of poverty, fragmented health care systems, and suboptimal access to health care because of socioeconomic inequalities, leading to the fact that children, adolescents, and young adults are disproportionally affected. Such tropical cardiomyopathies and nutritional CVD that have not been prevalent in high-income countries in the past decades are now reemerging. When treating migrants or refugees, it is important for attending physicians to consider the burden of endemic diseases in the countries of origin and the likelihood that such patients might be affected. In this review, the authors propose an approach for adequate diagnostic work-up leading to appropriate care for those with suspected or confirmed tropical cardiomyopathies and nutritional CVD.

The impact of Hydroxyurea on the rates of Vaso-occlusive crises in patients with sickle cell disease in Saudi Arabia: a single-center study

BACKGROUND

Vaso-occlusive crises (VOCs) are acute and common painful complication of sickle cell disease (SCD), and are the main reason behind the frequent emergency department visits among SCD patients. Hydroxyurea (HU) is an old and commonly used medication that demonstrated its effectiveness in reducing the risk of VOCs and the incidence of hospitalization. Although multiple studies have examined the impact of HU on the rates of VOCs, few have explored its effectiveness among SCD patients in Saudi Arabia.

METHODS

This was a single-center retrospective cohort study in which the electronic medical records of patients with SCD who have not had any previous exposure to HU prior to the initiation of HU treatment for ≥12 months were recruited. Paired t-test was conducted to examine the difference in the rates of VOCs, and levels of hemoglobin (Hgb), hematocrit (HCT), and platelet counts (PLT Ct) prior to the initiation of HU therapy and 12 months later. Multiple linear regression was conducted to examine whether age, gender, use of opioid analgesics, Hgb, HCT, and PLT Ct levels predict higher or lower rates of VOCs.

RESULTS

One hundred and fifty-six patients met the inclusion criteria and were included in the analysis. About 51% of the patients were males, and their mean age was 12.69 years. The mean HU dosage was 16.52 mg/kg/day, and the mean reduction in the rate of VOCs was 1.36 events per patient per year (95% CI [1.03-1.70], p < 0.0001) after the initiation of HU. Females were more likely to have greater reduction in the rates of VOCs in comparison to their male counterparts (β-estimate = 12.85, 95% CI [0.759-24.93], p = 0.0374).

CONCLUSION

The use of HU results in a significant reduction in the rates of VOCs and emergency department visits. Future studies with robust research designs should be conducted to further examine the impact of HU on VOCs, hospitalization, and length of stay as well as compare HU to other newly approved medications for SCD, such as crizanlizumab.

Haematological actions of androgens

In this review, we discuss the effects on androgens on the haemopoietic system, focussing largely on the effects of testosterone on erythropoiesis. Stimulation of erythropoiesis is one of the most consistent effects of testosterone treatment observed in clinical trials. In men with anaemia this effect can be beneficial. Conversely, erythrocytosis is one of the most common adverse effects of testosterone treatment with a relative risk of 8.14 (95% CI: 1.87-35.40) estimated by a recent meta-analysis of randomised placebo controlled clinical trials. A reduction in haemoglobin is commonly seen in men receiving androgen deprivation therapy for prostate cancer, and in transwomen receiving gender affirming therapy to reduce serum testosterone. While mechanisms by which androgens regulate erythropoiesis are not fully understood, it is likely that effects on erythropoietic progenitor cells and erythropoietin are involved, with secondary effects on iron metabolism. In contrast, whether androgens exert clinically relevant effects on white blood cells and on platelets requires further study.

Risk of vaso-occlusive episode after exposure to corticosteroids in patients with sickle cell disease

Vaso-occlusive episodes (VOEs) are a major concern in patients with sickle cell disease (SCD). Exposure to systemic corticosteroids has been suspected to increase the occurrence of VOEs in case reports or series. No comparative study has been conducted to investigate this risk, which is still debated. Several clinical trials demonstrated the effectiveness of corticosteroids for the treatment of VOEs, but with increased rates of readmission. The aim of the study was to assess the risk of hospitalization for VOE associated with exposure to systemic corticosteroids in patients with SCD. We used a case-case-time-control design in a nationwide population-based cohort built in the French national health insurance database between 2010 and 2018. The population included all patients with SCD with at least 1 hospitalization for VOE. Corticosteroids were identified using out-of-hospital dispensing data. The outcome was the first hospitalization for VOE. The case-case-time-control design induces self-adjustment for time-invariant confounders, including genotype. Analyses were adjusted for time-dependent confounders (infections, red blood transfusions) and stratified by exposure to hydroxyurea. Overall, 5151 patients were included in the main analysis. Corticosteroid exposure was significantly associated with the occurrence of hospitalizations for VOEs: adjusted odds ratio, 3.8; 95% confidence interval [CI], 2.4-5.6). In patients exposed to hydroxyurea, the adjusted odds ratio was 2.6 (95% CI, 1.1-6.4); it was 4.0 (95% CI, 2.5-6.3) in unexposed patients. These results were consistent in children and adults. In conclusion, systemic corticosteroids were associated to an increased risk of hospitalization for VOEs and should be limited in patients with SCD.