A microfluidic device for assessment of E-selectin-mediated neutrophil recruitment to inflamed endothelium and prediction of therapeutic response in sickle cell disease.

Neutrophil recruitment to the inflamed endothelium is a multistep process and is of utmost importance in the development of the hallmark vaso-occlusive crisis in sickle cell disease (SCD). However, there lacks a standardized, clinically feasible approach for assessing neutrophil recruitment to the inflamed endothelium for individualized risk stratification and therapeutic response prediction in SCD. Here, we describe a microfluidic device functionalized with E-selectin, a critical endothelial receptor for the neutrophil recruitment process, as a strategy to assess neutrophil binding under physiologic flow in normoxia and clinically relevant hypoxia in SCD. We show that hypoxia significantly enhances neutrophil binding to E-selectin and promotes the formation of neutrophil-platelet aggregates. Moreover, we identified two distinct patient populations: a more severe clinical phenotype with elevated lactate dehydrogenase levels and absolute reticulocyte counts but lowered fetal hemoglobin levels associated with constitutively less neutrophil binding to E-selectin. Mechanistically, we demonstrate that the extent of neutrophil activation correlates with membrane L-selectin shedding, resulting in the loss of ligand interaction sites with E-selectin. We also show that inhibition of E-selectin significantly reduces leukocyte recruitment to activated endothelial cells. Our findings add mechanistic insight into neutrophil-endothelial interactions under hypoxia and provide a clinically feasible means for assessing neutrophil binding to E-selectin using clinical whole blood samples, which can help guide therapeutic decisions for SCD patients.

Mental health assessment of youth with sickle cell disease and their primary caregivers during the COVID-19 pandemic.

Youth with sickle cell disease (SCD) and their caregivers are susceptible to stress and depression, perhaps exacerbated by pandemic-associated health and economic concerns. Most of the 50 youth-caregiver dyads enrolled in the multisite trial, Hydroxyurea Adherence for Personal Best in Sickle Cell Treatment (HABIT), took an online survey of self-reported mental health symptoms and food insecurity during the 2020 COVID-19 pandemic. Compared to largely pre-pandemic results, prevalence of mental health symptoms in dyad members appeared to have shifted: fewer youth and more caregivers were affected during the pandemic; many of both groups lacked optimism. Pandemic/post-pandemic screening of youth with SCD for mental health symptoms and food insecurity appears warranted.

Building access to care in adult sickle cell disease: defining models of care, essential components, and economic aspects.

Sickle cell disease (SCD) is the most common inherited blood disorder in the United States. It is a medically and socially complex, multisystem illness that affects individuals throughout the lifespan. Given improvements in care, most children with SCD survive into adulthood. However, access to adult sickle cell care is poor in many parts of the United States, resulting in increased acute care utilization, disjointed care delivery, and early mortality for patients. A dearth of nonmalignant hematology providers, the lack of a national SCD registry, and the absence of a centralized infrastructure to facilitate comparative quality assessment compounds these issues. As part of a workshop designed to train health care professionals in the skills necessary to establish clinical centers focused on the management of adults living with SCD, we defined an SCD center, elucidated required elements of a comprehensive adult SCD center, and discussed different models of care. There are also important economic impacts of these centers at an institutional and health system level. As more clinicians are trained in providing adult-focused SCD care, center designation will enhance the ability to undertake quality improvement and compare outcomes between SCD centers. Activities will include an assessment of the clinical effectiveness of expanded access to care, the implementation of SCD guidelines, and the efficacy of newly approved targeted medications. Details of this effort are provided.

Serial assessment of laser Doppler flow during acute pain crises in sickle cell disease.

Changes in basal laser Doppler flowmetry (LDF) of skin blood flow in sickle cell disease are reported to have pathophysiologic relevance in pain crisis. This is the first study to strictly control for LDF variability in determining the value of serial, basal (unprovoked) skin LDF as a practical method to assess resolution of acute pain crisis in sickle cell patients. Daily LDF measurements were repeated on the exact same skin areas of the calf and forehead throughout each of 12 hospital admissions for uncomplicated acute pain crisis. A progressive increase in perfusion was observed in the calf throughout hospitalization as pain crisis resolved, but measurement reproducibility in the calf was poor. Reproducibility in the forehead was better, but no significant trend over time in perfusion was seen. There was no significant correlation between perfusion and pain scores over time. There was also no significant pattern of LDF oscillations over time. In conclusion, only perfusion units and not oscillatory patterns of LDF have probable pathophysiological significance in sickle cell disease vaso-occlusion. The reproducibility of basal skin LDF specifically in sickle cell disease needs to be confirmed.