An oral carbon monoxide-releasing molecule protects against acute hyperhemolysis in sickle cell disease.

ABSTRACT: Acute hyperhemolysis is a severe life-threatening complication in patients with sickle cell disease (SCD) that may occur during delayed hemolytic transfusion reaction (DHTR), or vaso-occlusive crises associated with multiorgan failure. Here, we developed in vitro and in vivo animal models to mimic endothelial damage during the early phase of hyperhemolysis in SCD. We then used the carbon monoxide (CO)-releasing molecule CORM-401 and examined its effects against endothelial activation, damage, and inflammation inflicted by hemolysates containing red blood cell membrane-derived particles. The in vitro results revealed that CORM-401: (1) prevented the upregulation of relevant proinflammatory and proadhesion markers controlled by the NF-κB enhancer of activated B cells, and (2) abolished the expression of the nuclear factor erythroid-2-related factor 2 (Nrf2) that regulates the inducible antioxidant cell machinery. We also show in SCD mice that CORM-401 protects against hemolysate-induced acute damage of target organs such as the lung, liver, and kidney through modulation of NF-κB proinflammatory and Nrf2 antioxidant pathways. Our data demonstrate the efficacy of CORM-401 as a novel therapeutic agent to counteract hemolysate-induced organ damage during hyperhemolysis in SCD. This approach might be considered as possible preventive treatment in high-risk situations such as patients with SCD with history of DHTR.

Endurance training improves oxygen uptake/demand mismatch, metabolic flexibility and recovery in patients with sickle cell disease.

Patients with sickle cell disease (SCD) display lower slope coefficients of the oxygen uptake (V̇O2) versus work rate (W) relationship (delineating an O2 uptake/demand mismatch) and a poor metabolic flexibility. Because endurance training improves the microvascular network and increases the activity of oxidative enzymes, including one involved in lipid oxidation, endurance training might improve the slope coefficient of the V̇O2 versus W curve and the metabolic flexibility of SCD patients. Endurance training may also contribute to improve patients' post-exercise cardiopulmonary and metabolic recovery. Fifteen patients with SCD performed a submaximal incremental test on a cycle ergometer before (SIT1) and after (SIT2) 8 weeks of endurance training. Minute ventilation (V̇ E), ventilation rate, heart rate, V̇O2, carbon dioxide production (V̇CO2), respiratory exchange ratio, carbohydrate/lipid utilization and partitioning (including %Lipidox) and blood lactate concentration were measured during and after SIT1 and SIT2. At baseline, the slope coefficient of the V̇O2 versus W curve positively correlated with total hemoglobin, mean corpuscular hemoglobin and percentage of HbF. After training, the slope coefficient of the V̇O2 versus W curve was significantly higher and the increase in blood lactate concentration was delayed. If patients' energy metabolism apparently relied largely on carbohydrate sources during SIT1, %Lipidox tended to increase at low exercise intensities during SIT2, supporting a training-induced improvement of metabolic flexibility in patients with SCD. Post-exercise recovery of ventilation rate, V̇ E/V̇CO2, heart rate and blood lactate concentration was faster after training. We concluded that exercise training in patients with SCD: (i) ameliorated the oxygen uptake/ demand mismatch, (ii) blunted the metabolic inflexibility, and (iii) improved post-exercise cardiopulmonary and metabolic responses.

Impact of hospitalized vaso-occlusive crises in the previous calendar year on mortality and complications in adults with sickle cell disease: a French population-based study.

Background: Historically, sickle cell disease (SCD) patients experiencing frequent hospitalized vaso-occlusive crises (HVOC) have been associated with increased mortality, yet recent data reflecting the widespread use of hydroxyurea and advancements in disease management remain limited. Our study aims to assess the association between HVOC and mortality or severe complications in patients with SCD in this new treatment landscape. Methods: This was a retrospective observational cohort study using the French national health data system. Between 01-01-2012 and 12-31-2018, all SCD patients ≥16 years old (ICD-10 codes D57.0-2) were included and followed until 12-31-2018. HVOC was defined as a hospitalization of ≥1 night with primary diagnosis of SCD with crisis, following an emergency room visit. The association between HVOC and severe complications was assessed with a Cox proportional hazards model. Findings: In total, 8018 patients (56.6% females; 4538/8018) were included. The 2018 SCD standardized one-year period prevalence was 17.9 cases/100,000 person-years [17.4; 18.3]. The mean rate was 0.84 (1.88) HVOC/person-year. In 2018, 70% (5323/7605), 22% (1671/7605), and 8% (611/7605) of patients experienced 0, 1-2, or 3+ HVOCs, respectively. The median survival time between HVOCs was 415 days [386; 439]. Overall, 312 patients died (3.9%) with a mean age of 49.8 (19.4). Compared to patients without HVOC, the hazard ratios of death in patients with 1-2 or 3+ HVOCs the year prior to death were 1.67 [1.21; 2.30] and 3.70 [2.30; 5.93], respectively. Incidence of acute chest syndrome, pulmonary embolism, osteonecrosis, and sepsis increased with the HVOCs category, but not stroke. In 2018, 29.5% (180/611) of patients with 3+ HVOCs did not take hydroxyurea. Interpretation: Patients must be closely monitored during their hospitalizations to intensify treatment and check treatment compliance. Innovative therapies are also required. Funding: The study was funded by Novartis.

Decreased risk of underdosing with continuous infusion versus intermittent administration of cefotaxime in patients with sickle cell disease and acute chest syndrome.

OBJECTIVE: Underdosing of antibiotics is common in patients with sickle cell disease (SCD). We hypothesized that in critically-ill patients with SCD receiving cefotaxime during acute chest syndrome, the continuous infusion may outperform the intermittent administration in achieving pharmacokinetic/pharmacodynamic targets. DESIGN: Prospective before-after study. SETTINGS: Intensive-care unit of a French teaching hospital and sickle cell disease referral center. PATIENTS: Sixty consecutive episodes of severe acute chest syndrome in 58 adult patients with sickle cell disease. INTERVENTIONS: Patients were treated with intermittent administration during the first period (April 2016 -April 2018) and with continuous infusion during the second period (May 2018 -August 2019). MEASUREMENTS AND MAIN RESULTS: We included 60 episodes of acute chest syndrome in 58 patients (29 [25-34] years, 37/58 (64%) males). Daily dose of cefotaxime was similar between groups (59 [48-88] vs. 61 [57-64] mg/kg/day, p = 0.84). Most patients (>75%) presented a glomerular hyperfiltration with no difference between groups (p = 0.25). More patients had a cefotaxime trough level ≥2 mg/L with continuous infusion than intermittent administration: 28 (93%) vs. 5 (16%), p<0.001. The median residual concentration was higher in the continuous infusion than intermittent administration group: 10.5 [7.4-13.3] vs. 0 [0-0] mg/L, p<0.001. No infection relapse was observed in the entire cohort. Hospital length of stay was similar between groups. CONCLUSION: As compared to intermittent administration, continuous infusion of cefotaxime maximizes the pharmacokinetic/pharmacodynamic parameters in patients with SCD. The clinical outcome did not differ between the two administration methods; however, the study was underpowered to detect such a difference.

Determinants of cognitive dysfunction in adults with sickle cell-related stroke or suspected neurological morbidity.

ABSTRACT: The prognosis of sickle cell disease (SCD) in adults is determined primarily by damage to targeted organs such as the brain. Cognitive dysfunction in SCD is a common chronic neurological manifestation, but studies remain mostly descriptive in adults. The objective of this study was to better characterize the cognitive profile and the association between cognitive dysfunction and brain lesions. We included adult patients with SCD referred for a neurological assessment. An adapted battery of neuropsychological tests was used to assess cognitive deficits. Brain or arterial abnormalities were assessed using brain magnetic resonance imaging/magnetic resonance angiography and a cervical and transcranial Doppler ultrasound. The cognitive profile of 96 patients was characterized by deficits in processing speed (58%), short-term memory (34%), and working memory (24%). Brain infarcts were found in 56% of patients and intracranial vasculopathy in 49%. Twenty percent of patients had no brain abnormalities. Processing speed dysfunction was associated with territorial infarcts (odds ratio [OR], 3.1; P = .03) and education outside of France (OR, 4.7; P = .02). Short-term memory dysfunction was associated with territorial infarcts (OR, 3.4; P = .01) and a low educational level (OR, 8.2; P = .01). Working memory dysfunction was associated with a low educational level (OR, 4.3; P = .05) and vasculopathy (OR, 3.7; P = .03). Cognitive dysfunction appears to be a hallmark sign of SCD, particularly for adults with sickle cell-related stroke or suspected neurological morbidity. Assessment of such dysfunction could be used in longitudinal follow-up and clinical trials.

THromboprophylaxis In Sickle Cell Disease with central venous catheters (THIS): an internal pilot randomised controlled trial protocol.

INTRODUCTION: Individuals with sickle cell disease (SCD) and central venous catheters (CVC) are at high risk for venous thromboembolism (VTE). Minimal data exist regarding the use of anticoagulation as thromboprophylaxis of VTE in this demographic, and as a result, clinical equipoise exists. Prophylactic dose rivaroxaban, a direct oral anticoagulant, is efficacious and safe as thromboprophylaxis in other demographics, and may be an optimal agent in SCD with CVC. Prior to conducting a full clinical trial to assess rivaroxaban as thromboprophylaxis in SCD with CVC, a pilot study is needed to gauge its feasibility. METHODS AND ANALYSIS: THromboprophylaxis In Sickle Cell Disease pilot trial is an investigator-initiated, multicentre, double-blinded, randomised controlled trial (RCT) assessing if it is feasible and safe to conduct an adequately powered RCT comparing rivaroxaban to matching placebo as thromboprophylaxis in those with SCD and CVC. Fifty adult patients with SCD and CVC will be randomised to receive either rivaroxaban 10 mg daily or matching placebo for the duration of the CVC in situ for up to 1 year. After randomisation, follow-up visits will occur every 3 months. The primary outcomes pertain to the feasibility of a full trial and include numbers of eligible and recruited participants. Exploratory outcomes include overall incidence of VTE and bleeding complications, as well as quality of life. If the full trial is feasible, blinding will be maintained and patients in the pilot study will be included in the full trial. ETHICS AND DISSEMINATION: The trial was initially approved by the University Health Network Research Ethics Board (REB) in Toronto, Canada. All sites will obtain approval from their respective REB prior to commencement of study activities. Study results will be disseminated through presentations at medical conferences and peer-reviewed publications. TRIAL REGISTRATION NUMBER: NCT05033314.

Cardiac diastolic maladaptation is associated with the severity of exercise intolerance in sickle cell anemia patients.

This pilot study focusing on Sickle Cell Anemia (SCA) patients offers a comprehensive and integrative evaluation of respiratory, cardiovascular, hemodynamic, and metabolic variables during exercise. Knowing that diastolic dysfunction is frequent in this population, we hypothesize that a lack of cardiac adaptation through exercise might lead to premature increase in blood lactate concentrations in SCA patients, a potential trigger for acute disease complication. SCA patients were prospectively included in PHYSIO-EXDRE study and underwent a comprehensive stress test with a standardized incremental exercise protocol up to 4 mmol L-1 blood lactate concentration (BL4). Gas exchange, capillary lactate concentration and echocardiography were performed at baseline, during stress test (at ∼ 2 mmol L-1) and BL4. The population was divided into two groups and compared according to the median value of percentage of theoretical peak oxygen uptake (% V ˙ O 2 p e a k t h ) at BL4. Twenty-nine patients were included (42 ± 12 years old, 48% of women). Most patients reached BL4 at low-intensity exercise [median value of predicted power output (W) was 37%], which corresponds to daily life activities. The median value of % V ˙ O 2 p e a k t h at BL4 was 39%. Interestingly, diastolic maladaptation using echocardiography during stress test along with hemoglobin concentration were independently associated to early occurrence of BL4. As BL4 occurs for low-intensity exercises, SCA patients may be subject to acidosis-related complications even during their daily life activities. Beyond assessing physical capacities, our study underlines that diastolic maladaptation during exercise is associated with an early increase in blood lactate concentration.

Atrial Arrhythmia in Sickle Cell Anemia Adults: A missing link towards understanding and preventing strokes.

Although sickle cell disease (SCD) patients carry both significant left atrial (LA) remodeling and increased risk of stroke, the prevalence of atrial arrhythmia (AA) has never been prospectively evaluated. This study aims to investigate the prevalence and predictors of atrial arrhythmia in homozygous SCD (SCA). From 2019 to 2022, 130 patients with SCA were referred to the physiology department to specifically analyze cardiac function and prospectively included in the DREPACOEUR registry. They underwent a 24-hour electrocardiogram monitoring (24h-Holter), transthoracic echocardiography, and laboratory tests on the same day. The primary endpoint was the occurrence of AA, defined by the presence of excessive supraventricular ectopic activity (ESVEA) on ECG-Holter (i.e., >720 premature atrial contractions [PACs] or any run ≥ 20 PACs), recent history of paroxysmal atrial fibrillation (AF), or persistent AF. The mean patient age was 45±12 years and 48% of male. Overall, AA was found in 34 (26%) patients. Age (52±9 vs. 42±12 years, P=0.002), LA dilation (LAVi, 71±24 vs. 52±14 ml/m², P<0.001) and history of stroke without underlying cerebral vasculopathy or other defined cause (26% vs. 5%, P=0.009, OR=6.6 [1.4; 30.3]) were independently associated with AA. Age and LAVi correlated with PAC load per 24 hours on ECG-Holter (R=0.56 and 0.33, P<0.001 respectively) and an age over 47 years or a LAVi >55mL/m² could predict AA with a PPV of 33% and a NPV of 92%. AAs are frequent in SCA patients and increase with age and LA remodeling, leading to a major additional risk factor for ischemic stroke. This study provides arguments and means to early screen for AA potentially preventing cerebral complications.