Sickle cell disease biochip: a functional red blood cell adhesion assay for monitoring sickle cell disease

Abstract

Sickle cell disease (SCD) afflicts millions of people worldwide and is associated with considerable morbidity and mortality. Chronic and acute vaso-occlusion are the clinical hallmarks of SCD and can result in pain crisis, widespread organ damage, and early movtality. Even though the molecular underpinnings of SCD were identified more than 60 years ago, there are no molecular or biophysical markers of disease severity that are feasibly measured in the clinic. Abnormal cellular adhesion to vascular endothelium is at the root of vaso-occlusion. However, cellular adhesion is not currently evaluated clinically. Here, we present a clinically applicable microfluidic device (SCD biochip) that allows serial quantitative evaluation of red blood cell (RBC) adhesion to endothelium-associated protein-immobilized microchannels, in a closed and preprocessing-free system. With the SCD biochip, we have analyzed blood samples from more than 100 subjects and have shown associations between the measured RBC adhesion to endothelium-associated proteins (fibronectin and laminin) and individual RBC characteristics, including hemoglobin content, fetal hemoglobin concentration, plasma lactate dehydrogenase level, and reticulocyte count. The SCD biochip is a functional adhesion assay, reflecting quantitative evaluation of RBC adhesion, which could be used at baseline, during crises, relative to various long-term complications, and before and after therapeutic interventions.

Emerging point-of-care technologies for sickle cell disease screening and monitoring

“…Adhesion to the endothelium may prolong delay time, and increase polymer formation and fragility as the RBC passes through the vasculature 51 . Furthermore, an association between hemolysis and increased SCD RBC adhesion to components of the endothelium/sub-endothelial surface has been shown recently 34 .…”

“…Though being the first discovered molecular disease, SCD has been known to be highly complex due to its heterogeneous characteristics in pathophysiology, making it hard to pinpoint the underlining biological mechanisms. Many facets of SCD pathophysiology have been investigated, including hemoglobin polymerization 20–22 , cellular deformability 23–28 , adhesion 25, 29–34 , hemodynamic changes 35, 36 , and clinical heterogeneity 6, 7 .…”

“…Key clinical and experimental studies in SCD literature, performed via flow chambers or ex vivo rat mesocecum 29, 30, 54, 56 , have shown that RBC adhesion and deformability, WBC adhesion and activation 57 , and endothelial activation contribute to the pathogenesis of vaso-occlusion 33, 56, 58, 59 and may correlate with disease severity 34, 48, 60, 61 . Abnormal RBC adhesion to endothelium has associated with disease activity 34, 48 and has diminished with treatment 34, 62 , with variable but elevated adhesion at clinical baseline. Associations with clinical status have shown using FACS analysis of membrane protein components 63–65 .…”

“…Associations with clinical status have shown using FACS analysis of membrane protein components 63–65 . However, few longitudinal measurements of adhesion at baseline and with therapy have been performed due to lack of convenient reproducible adhesion assays 30, 34 .…”

Anemia falciforme: uma revisão acerca da doença, novos métodos diagnósticos e tratamento

“…Além do genótipo, a hemoglobina fetal (HbF) é um outro fator que interfere na gravidade da doença pois modula a polimerização da hemoglobina S. Um estudo caso-controle realizado por Alapan et al (2016) no hospital universitário de Cleveland, Ohio, utilizou mais de 100 amostras de sangue e avaliou o nível de HbF no sangue e a adesividade endotelial das hemácias de pacientes diagnosticados com anemia falciforme com genótipos HbSS, HbSC e HbSC/S β + e de indivíduos saudáveis (genótipo HbAA). Para quantificar essa adesividade foi utilizado um biochip que simula os microvasos fisiológicos.…”