Early hydroxyurea use is neuroprotective in children with sickle cell anemia

Factors associated with adverse outcome among children with sickle cell disease admitted to the pediatric intensive care unit: an observational cohort

BACKGROUND

Sickle cell disease (SCD) is one of the most frequent inherited diseases in the world. Over the last decades, in high-income countries, an important decrease in mortality have been observed due to the improvement of care. However, children with SCD can become critically ill and require admission in Pediatric Intensive Care Units (PICU). The purpose of this study was to describe the epidemiology of children with SCD admitted to PICU for acute crisis and to identify factors associated with adverse outcome (AO).

METHODS

We conducted a retrospective study in a Tertiary Hospital in France including all consecutive children with SCD admitted to PICU between January 1st, 2009 and December 31, 2019. We collected baseline patient's characteristics, clinical and biological data as well as treatments and life sustaining therapies used in the PICU. Patients were defined as experiencing AO in case of death during stay and/or need for invasive mechanical ventilation (MV) and/or for non-invasive ventilation (NIV) for more than 3 days and/or need for vasopressors and/or need for renal replacement therapy.

RESULTS

We included 579 admissions in 395 patients, mainly of SS genotype (90%) with a median age of 9.2 years [5.5-13.4] and a median baseline hemoglobin of 8.0 g/dl (7.5-8.8). The two main reasons for admission were acute chest syndrome (ACS) (n = 331, 57%) and vaso-occlusive crisis refractory to first line therapy (n = 99, 17%). Half of patients required NIV and 47 (8%) required MV. The overall length of stay was 3 days [1-4] and seven (1%) patients died during PICU stay.There was a total of 113 (20%) admissions with AO and on multivariable analysis, baseline hemoglobin < 8 g/dL, history of bronchial obstruction and admission for ACS were associated with AO. There was no difference in the proportion of hydroxyurea treatment or exchange transfusion program between patients with AO and the other patients.

CONCLUSIONS

Baseline hemoglobin < 8 g/dL, history of bronchial obstruction and admission for ACS were the strongest risk factors for severe evolution in SCD children admitted to PICU. These factors could be taken into consideration when choosing the adequate therapeutic options.

Montreal cognitive assessment in Brazilian adults with sickle cell disease: The burdens of poor sociocultural background

Sickle cell disease (SCD) patients are at higher risk of developing silent cerebral infarcts and overt stroke, which may reflect cognitive impairment, functional limitations, and worse quality of life. The cognitive function of Brazilian adult SCD patients (n = 124; 19-70 years; 56 men; 79 SS, 28 SC, 10 S/β0, 7 S/β+) was screened through Montreal Cognitive Assessment (MoCA) and correlated the results with possible predictive factors for test performance, including sociocultural, clinical, laboratory data and brain imaging. The Median MoCA score was 23 (8-30); 70% had a 25-or-less score, suggesting some level of cognitive impairment. There were no significant associations between MoCA results and any clinical or laboratory data in SS and SC patients; however, a significant correlation (P = 0.03) with stroke was found in HbS/β-thalassemic patients. Correlations were further detected according to sociodemographic conditions, such as age (r = -0.316; P < 0.001), age at first job (r = 0.221; P = 0.018), personal (r = 0.23; P = 0.012) and per capita familiar incomes (r = 0.303; P = 0.001), personal (r = 0.61; P = 0), maternal (r = 0.536; P = 0), and paternal educational status (r = 0.441; P = 0). We further sought independent predictors of performance using multivariable regressions and increased education was an independent predictor of better scores in MoCA (0.8099, 95% confidence interval [CI]: 0.509-1.111). Brain imaging analysis showed significant and progressive atrophy in important cerebral areas related to memory, learning, and executive function. These data point to the high prevalence and impact of cognitive decline in adult SCD patients, mirrored in brain atrophic areas. It is also possible to observe the influence of sociodemographic conditions on patients' cognitive performances and the need for creating focused therapeutic plans that address these deficiencies. Moreover, the absence of a significant correlation of MoCA values with stroke in the SS and SC groups may be related to the worst sociocultural and economic conditions of the Brazilian African descent population, in which the impact of low educational stimulation on cognitive function can outweigh even the anatomical damage caused by the disease.

The evolving treatment landscape for children with sickle cell disease

Sickle cell disease is the most common inherited pathological haemoglobinopathy. Over the past 30 years, disease-related morbidity and mortality have improved in high-income countries due to advances in preventive care and treatments. Established disease-modifying therapies, such as hydroxyurea (hydrocarbamide), are continuing to have an important role in the treatment of sickle cell disease, and newer agents also show promise. In the past 5 years, the US Food and Drug Administration approved three additional sickle cell disease-modifying medications, and new gene therapies have been developed as an alternative curative treatment to haematopoietic stem-cell transplantation. In this Review, we discuss the current treatment landscape for paediatric sickle cell disease and emerging innovations in care. We also review the need for close, long-term management for children receiving newer therapies and the importance of ongoing investment in people with sickle cell disease in low-income and middle-income countries.

Molecular and environmental contributors to neurological complications in sickle cell disease

Sickle cell disease (SCD) is an inherited hemoglobinopathy in which affected hemoglobin polymerizes under hypoxic conditions resulting in red cell distortion and chronic hemolytic anemia. SCD affects millions of people worldwide, primarily in Sub-Saharan Africa and the Indian subcontinent. Due to vaso-occlusion of sickled red cells within the microvasculature, SCD affects virtually every organ system and causes significant morbidity and early mortality. The neurological complications of SCD are particularly devastating and diverse, ranging from overt stroke to covert cerebral injury, including silent cerebral infarctions and blood vessel tortuosity. However, even individuals without evidence of neuroanatomical changes in brain imaging have evidence of cognitive deficits compared to matched healthy controls likely due to chronic cerebral hypoxemia and neuroinflammation. In this review, we first examined the biological contributors to SCD-related neurological complications and then discussed the equally important socioenvironmental contributors. We then discuss the evidence for neuroprotection from the two primary disease-modifying therapies, chronic monthly blood transfusions and hydroxyurea, and end with several experimental therapies designed to specifically target these complications.

Therapeutic perspective for children and young adults living with thalassemia and sickle cell disease

Hemoglobinopathies, including thalassemias and sickle cell disease, are the most common monogenic diseases worldwide, with estimated annual births of more than 330,000 affected infants. Hemoglobin disorders account for about 3.4% of deaths in children under 5 years of age. The distribution of these diseases is historically linked to current or previously malaria-endemic regions; however, immigration has led to a worldwide distribution of these diseases, making them a global health problem. During the last decade, new treatment approaches and novel therapies have been proposed, some of which have the potential to change the natural history of these disorders. Indeed, the first erythroid maturation agent, luspatercept, and gene therapy have been approved for beta-thalassemia adult patients. For sickle cell disease, molecules targeting vaso-occlusion and hemoglobin S polymerization include crizanlizumab, which has been approved for patients ≥ 16 years, voxelotor approved for patients ≥ 12 years, and L-glutamine for patients older than 5 years.    Conclusion: We herein present the most recent advances and future perspectives in thalassemia and sickle cell disease treatment, including new drugs, gene therapy, and gene editing, and the current clinical trial status in the pediatric populations. What is Known: • Red blood cell transfusions, iron chelation therapy and hematopoietic stem cell transplantation have been the mainstay of treatment of thalassemia patients for decades. • For sickle cell disease, until 2005, treatment strategies were mostly the same as those for thalassemia, with the option of simple transfusion or exchange transfusion. In 2007, hydroxyurea was approved for patients ≥ 2 years old. What is New: • In 2019, gene therapy with betibeglogene autotemcel (LentiGlobin BB305) was approved for TDT patients ≥ 12 years old non β0/β0 without matched sibling donor. • Starting from 2017 several new drugs, such as L-glutamine (approved only by FDA), crizanlizumab (approved by FDA and EMA for patients ≥ 16 years), and lastly voxelotor (approved by FDA and EMA for patients ≥ 12 years old).

Working memory and school readiness in preschool children with sickle cell disease compared to demographically matched controls

Children diagnosed with sickle cell disease (SCD) are at risk of the development of neurobehavioural problems early in life. Specific impairments in executive function skills, including working memory, have been documented in school-aged children with SCD. These executive skills are known to strongly contribute to early academic skills and preparedness for entering kindergarten. This study examined working memory and school readiness in preschool children with SCD compared to a healthy control group matched for race, sex and parent education. A total of 84 patients diagnosed with SCD (61.9% haemoglobin [Hb]SS/HbSβ0 -thalassaemia) and 168 controls completed testing. The mean (SD) ages of patients and controls at testing were 4.53 (0.38) and 4.44 (0.65) years respectively. The SCD group performed worse than controls on measures of executive function, working memory and school readiness (p < 0.01; Cohen's D range: 0.32-0.39). Measures of working memory were associated with school readiness after accounting for early adaptive development. Multiple linear regression models among patients diagnosed with SCD revealed that college education of the primary caregiver was positively associated with school readiness (p < 0.001) after controlling for sex, genotype, age and early adaptive development. These results highlight the need to implement school readiness interventions in young children diagnosed with SCD emphasising executive function skills.