Next generation personalized blood vessel-on-chip: Mimicking patient-specific pathophysiology in sickle cell disease through blood-derived endothelial progenitors.

Advances in tissue engineering and organ-chip technology have accelerated in vitro research of the vascular system. Incorporating patient-derived endothelial cells either through direct tissue biopsies or stem cell differentiation techniques further enhance the impact of organ-chips on precision medicine. However, these methods pose certain challenges and might be difficult to adopt in lab, thereby limiting the predictive power of organ-chips. Here we report the use of Blood Outgrowth Endothelial Cells (BOECs) directly isolated from patient blood as an alternative to primary and iPSC-derived endothelial cells for organ-chip applications. BOECs exhibit the gold-standard endothelial hallmarks of the "cobblestone" morphology in vitro. When compared to primary HUVECs and iPSC-derived endothelial cells, healthy BOECs reveal similar levels of growth rates, migration capabilities, de novo vessel formation, response to fluid shear stress and exogenous cytokine inflammation in vitro. To study patient-specificity, we derive BOECs from two sickle cell disease (SCD) patients with known differences in clinical severity of the disease. Through next generation RNA sequencing, differential gene expression (DGE) analysis and qRT-PCR, we reveal that SCD patient-derived BOECs are indeed activated and that the more severe SCD patient exhibited a greater magnitude of activation. This is further confirmed by real-time recalcified whole blood perfusion through endothelialized vessel-chips. Blood-derived endothelial cells may be employed in preclinical research for developing more robust and personalized next-generation disease models that can ultimately enable clinicians in identifying individuals at high risk of stroke or cardiovascular complications.