Mortality in sickle cell disease

Transsulfuration pathway activation attenuates oxidative stress and ferroptosis in sickle primary erythroblasts and transgenic mice

The transsulfuration (TSS) pathway is an alternative source of cysteine for glutathione synthesis. Little of the TSS pathway in antioxidant capacity in sickle cell disease (SCD) is known. Here, we evaluate the effects of TSS pathway activation through cystathionine beta-synthase (CBS) to attenuate reactive oxygen species (ROS) and ferroptosis stresses in SCD. A vital contribution of the TSS pathway in sustaining cysteine levels is detected only under hemin exposure or physiological but not supraphysiological cystine supplement. Mechanistic studies show that hemin suppresses CBS expression to inhibit the TSS pathway and de novo cysteine biosynthesis. By contrast, the expression of CBS is inducible by dimethyl fumarate (DMF) through nuclear factor erythroid 2-related factor 2 (NRF2) activation and CpG islands DNA hydroxymethylation. DMF induces the expression of L-2-hydroxyglutarate dehydrogenase (L2HGDH) to downregulate L-2-hydroxyglutarate (L2HG) and increase global and locus-specific DNA hydroxymethylation levels. This DMF-upregulated DNA hydroxymethylation affects CBS locus chromatin structure modifications and upregulates gene expression. Our results suggest that CBS of the TSS pathway plays an important role in maintaining cysteine levels under restricted cystine availability or excess hemin exposure, and CBS upregulation by DMF increases the cellular glutathione levels to protect against ROS and ferroptosis stress in SCD.

Unexpected Death of a Sickle Cell Disease Patient: A Case Report and Literature Review

Sickle cell disease (SCD) is an autosomal recessive genetic disorder characterized by the abnormal formation of sickle hemoglobin (HbS). Under conditions of deoxygenation, HbS undergoes polymerization, resulting in microvascular occlusion, tissue hypoxia, and infarction. The elevated mortality rate associated with SCD is primarily attributed to complications such as sepsis, acute chest syndrome, stroke, acute multiorgan failure, and pulmonary hypertension. Despite advancements in awareness and treatments, preventing mortality in young individuals with SCD remains a formidable challenge. In an effort to shed light on these challenges, we present a case of unexpected death associated with SCD to emphasize the pressing need for continued research and intervention strategies to improve patient outcomes.

Simvastatin-Mediated Nrf2 Activation Induces Fetal Hemoglobin and Antioxidant Enzyme Expression to Ameliorate the Phenotype of Sickle Cell Disease

Sickle cell disease (SCD) is a pathophysiological condition of chronic hemolysis, oxidative stress, and elevated inflammation. The transcription factor Nrf2 is a master regulator of oxidative stress. Here, we report that the FDA-approved oral agent simvastatin, an inhibitor of hydroxymethyl-glutaryl coenzyme A reductase, significantly activates the expression of Nrf2 and antioxidant enzymes. Simvastatin also induces fetal hemoglobin expression in SCD patient primary erythroid progenitors and a transgenic mouse model. Simvastatin alleviates SCD symptoms by decreasing hemoglobin S sickling, oxidative stress, and inflammatory stress in erythroblasts. Particularly, simvastatin increases cellular levels of cystine, the precursor for the biosynthesis of the antioxidant reduced glutathione, and decreases the iron content in SCD mouse spleen and liver tissues. Mechanistic studies suggest that simvastatin suppresses the expression of the critical histone methyltransferase enhancer of zeste homolog 2 to reduce both global and gene-specific histone H3 lysine 27 trimethylation. These chromatin structural changes promote the assembly of transcription complexes to fetal γ-globin and antioxidant gene regulatory regions in an antioxidant response element-dependent manner. In summary, our findings suggest that simvastatin activates fetal hemoglobin and antioxidant protein expression, modulates iron and cystine/reduced glutathione levels to improve the phenotype of SCD, and represents a therapeutic strategy for further development.

A Stress and Pain Self-management mHealth App for Adult Outpatients With Sickle Cell Disease: Protocol for a Randomized Controlled Study

BACKGROUND

This paper describes the research protocol for a randomized controlled trial of a self-management intervention for adults diagnosed with sickle cell disease (SCD). People living with SCD experience lifelong recurrent episodes of acute and chronic pain, which are exacerbated by stress.

OBJECTIVE

This study aims to decrease stress and improve SCD pain control with reduced opioid use through an intervention with self-management relaxation exercises, named You Cope, We Support (YCWS). Building on our previous findings from formative studies, this study is designed to test the efficacy of YCWS on stress intensity, pain intensity, and opioid use in adults with SCD.

METHODS

A randomized controlled trial of the short-term (8 weeks) and long-term (6 months) effects of YCWS on stress, pain, and opioid use will be conducted with 170 adults with SCD. Patients will be randomized based on 1:1 ratio (stratified on pain intensity [≤5 or >5]) to be either in the experimental (self-monitoring of outcomes, alerts or reminders, and use of YCWS [relaxation and distraction exercises and support]) or control (self-monitoring of outcomes and alerts or reminders) group. Patients will be asked to report outcomes daily. During weeks 1 to 8, patients in both groups will receive system-generated alerts or reminders via phone call, text, or email to facilitate data entry (both groups) and intervention use support (experimental). If the participant does not enter data after 24 hours, the study support staff will contact them for data entry troubleshooting (both groups) and YCWS use (experimental). We will time stamp and track patients' web-based activities to understand the study context and conduct exit interviews on the acceptability of system-generated and staff support. This study was approved by our institutional review board.

RESULTS

This study was funded by the National Institute of Nursing Research of the National Institutes of Health in 2020. The study began in March 2021 and will be completed in June 2025. As of April 2022, we have enrolled 45.9% (78/170) of patients. We will analyze the data using mixed effects regression models (short term and long term) to account for the repeated measurements over time and use machine learning to construct and evaluate prediction models. Owing to the COVID-19 pandemic, the study was modified to allow for mail-in consent process, internet-based consent process via email or Zoom videoconference, devices delivered by FedEx, and training via Zoom videoconference.

CONCLUSIONS

We expect the intervention group to report reductions in pain intensity (primary outcome; 0-10 scale) and in stress intensity (0-10 scale) and opioid use (Wisepill event medication monitoring system), which are secondary outcomes. Our study will contribute to advancing the use of nonopioid therapy such as guided relaxation and distraction techniques for managing SCD pain.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04484272; https://clinicaltrials.gov/ct2/show/NCT04484272.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/33818.

Cross-cultural adaptation of the Pain Medication Questionnaire for use in Brazil

BACKGROUND

The Pain Medication Questionnaire (PMQ) assesses the risk of opioid abuse in people with non-oncological chronic pain.

METHODS

This is a methodological study conducted at a hemotherapy centre in Recife, Pernambuco state, Brazil. A Cross-cultural adaptation was carried out by a committee of nine specialists, and we applied the PMQ to a pre-final sample of 40 individuals with sickle cell anemia, in addition to a sociodemographic and clinical questionnaire.

RESULTS

The mean agreement indexes for PMQ equivalences were the following: semantic (0.996), idiomatic (0.970), experiential (0.991), conceptual (0.953), language clarity (0.991), practical relevance (0.906), and theoretical relevance (0.945). Assessment of the PMQ showed that 50% of participants obtained a score equivalent to medium risk of opioid abuse. Cronbach's alpha coefficient for the adapted PMQ instrument was 0.705, ranging from 0.641 to 0.736 among its items.

CONCLUSION

The cross-cultural adaptation of the Pain Medication Questionnaire was satisfactory and easy to apply in the Brazilian population. It is clinically relevant, contributing professional practice and enlightening patients with sickle cell anemia on their behavioral dynamics with respect to opioid consumption. It will also contribute to teaching and research, because it is a useful tool for investigating the risk of abusive behavior in people with chronic pain.

Predictors of mortality in adults with Sickle cell disease admitted to intensive care unit in Bahrain

OBJECTIVE

Sickle cell disease (SCD) is one of the most common genetic blood disorders in Bahrain. However, there is a paucity of data regarding the clinical presentation of SCD patients who require ICU admission. This study aimed to describe the epidemiological data of SCD patients admitted to the ICU and to identify predictors of mortality in order to help intensivists identify patients at most risk.

METHOD

This study used a retrospective, descriptive, and correlational design. Records of 210 SCD patients admitted to the ICU in Salmaniya Medical Complex (SMC) were reviewed.

RESULTS

210 patient with SCD were admitted to ICU during study period. The main reason for ICU admission was acute chest syndrome. The mortality rate of SCD patients in the ICU was 12.7%. The four significant predictors of mortality were age, number of previous hospitalizations, length of stay, and need of renal replacement therapy. Non-survivors were older than survivors (M=38.6 vs. M=30.3years, U=1685, z=-2.2, P=0.025), were less frequently hospitalized (M=19 vs. M=46 times, U=1274, z=-3.7, P=0.000), had shorter lengths of stay in the ICU (M=3.1 vs. M=5.5days, U=1145, z=-4, P=0.000), and more likely to require renal replacement therapy the p=0.0297 than the survivors. The combined effect of these predictors was modelled with cox regression and found to be statistically significant. Gender, presence of comorbid conditions, level of hemoglobin on admission, and need for blood transfusions were not found to be predictors for mortality.

CONCLUSION

Acute chest syndrome was the main reason for SCD patients to be admitted to the ICU. Older age, less frequent hospitalization, shorter stays in the ICU, and the need for renal replacement therapy were found to be indicators of high mortality rate SCD patients.

Brief communication: oxygen isotopes as a biomarker for sickle-cell disease? Results from transgenic mice expressing human hemoglobin S genes

The origins of sickle-cell disease (SCD) are well understood, as are its evolutionary pressures on humans and pathological presentation. However, because it has not been possible to identify SCD in archaeological contexts, its biocultural effects on past populations are unknown. Previous research investigating oxygen isotope fractionation during respiration among anemics suggests that oxygen isotopes in bone apatite may provide a biological marker for SCD in skeletal remains. This pilot study reports δ(18) O ratios in bone apatite of transgenic laboratory mice expressing human SCD globins and compares them to healthy control mice. The δ(18) O ratios of sick mice are significantly lower than those of healthy mice (-5.6‰ vs. -4.5‰; P = 0.002), and the sickest mice exhibit the lowest ratios of all (mean δ(18) O = -5.8‰). These preliminary results suggest that this method may be usefully applied to skeletal materials of past human populations whose diets and water sources do not differ substantially.

Long-term outcomes in patients with sickle cell disease and frequent vaso-occlusive crises

BACKGROUND

The frequency of vaso-occlusive crises correlates with mortality in patients with sickle cell disease (SCD). We examined the degree to which a high number of hospitalization days for these events affected survival.

PATIENTS AND METHODS

We reviewed data for 58 adult patients with SCD (mean age, 29.9 +/- 7.3 years) treated at our hospital between 1986 and 1994 who had at least 100 hospitalization days during any of these years. Their mean follow up period was 6.65 years (median, 6.84 years; range, 0.15-14.51 years).

RESULTS

Thirty-five patients (60.3%) died during follow-up. In multivariate analysis that included age, gender, and numbers of transfusions and hospitalization days, only age was significantly associated with mortality. The National Cooperative Study of Sickle Cell Disease (CSSCD) estimates the 10-year mortality at 15% for all 20-year old SS patients and also for all 30-year-old women. For 30-year-old men, the CSSCD estimated a 10-year mortality of about 28%. Thus, the 60.3% mortality of our patients after a median follow-up of only 6.84 years was substantially higher. Fifty-one patients were still alive after 1992, when hydroxyurea became available for SCD. The median survival of 15 hydroxyurea-treated patients was 7.3 years, compared with 4.3 years in 36 patients who did not take the drug.

CONCLUSIONS

Mortality for patients with SCD with a high number of hospitalization days was much higher than that expected for patients with SCD in general. There was a (nonsignificant) trend for longer survival in these severely ill patients if they took hydroxyurea.

A randomized trial of captopril for microalbuminuria in normotensive adults with sickle cell anemia

PURPOSE

Nephropathy is a common complication of sickle cell anemia and is often preceded by proteinurea. Our aim was to evaluate the effect of angiotensin-converting enzyme inhibition on microalbuminuria in sickle cell patients.

PATIENTS AND METHODS

We performed a randomized, double-blind, placebo-controlled trial in 22 normotensive patients with sickle cell anemia and persistent microalbuminuria. Patients received captopril (25 mg/day) or placebo and were followed up for 6 months. Albuminuria, blood pressure, and serum creatinine and hemoglobin concentrations were measured at baseline and at 1, 3, and 6 months. The primary outcome variable was the 6-month change in albuminuria between the two groups.

RESULTS

Baseline albuminuria was 121 (SD 66) mg per 24 hours in the captopril group and 107 (SD 86) mg per 24 hours in the placebo group. Microalbuminuria decreased from baseline in the captopril group but increased in the placebo group. The mean absolute change and the mean percentage change in microalbuminuria were significantly different between the two groups at 6 months (absolute change -45 mg per 24 hours in the captopril group versus +18 mg per 24 hours in the placebo group, P <0.01; and percentage change -37% in the captopril group versus +17% in the placebo group, P <0.01). The 95% confidence intervals (CI) for the difference in albuminuria between the two groups were 63 (CI 40 to 86) mg per 24 hours for the mean absolute change and 54% (CI 22% to 85%) for the mean percentage change. Blood pressure decreased slightly from baseline in captopril-treated patients and did not change in the placebo group. The change was significantly different between the two groups only for diastolic blood pressure at 6 months (P <0.01).

CONCLUSION

Captopril reduces albuminuria and slightly decreases blood pressure in patients with sickle cell anemia. More studies are required to demonstrate the sustained benefit on protein excretion.