Human bone marrow-derived mesenchymal stem cells play a role as a vascular pericyte in the reconstruction of human BBB on the angiogenesis microfluidic chip.

A blood-brain barrier (BBB) on a chip similar to the in vivo BBB is important for evaluating the efficacy of reparative cell therapeutics for ischemic stroke in vitro. In this study, we established human BBB-like microvasculature on an angiogenesis microfluidic chip and analyzed the role of human pericytes (hPCs) and human astrocytes (hACs) on the architecture of human brain microvascular endothelial cells (hBMEC)-derived microvasculature on a chip. We found that human bone marrow mesenchymal stem cells (hBM-MSCs) play a role as perivascular pericytes in tight BBB reformation with a better vessel-constrictive capacity than that of hPCs, providing evidence of reparative stem cells on BBB repair rather than a paracrine effect. We also demonstrated that pericytes play an important role in vessel constriction, and astrocytes may induce the maturation of a capillary network. Higher expression of VEGF, SDF-1α, PDGFRβ, N-cadherin, and α-SMA in hBM-MSCs than in hPCs and their subsequent downregulation with hBMEC co-culture suggest that hBM-MSCs may be better recruited and engaged in the BBB-microvasculature than hPCs. Collectively, the human BBB on a chip may be adopted as an alternative to evaluate in vitro cellular behavior and the engagement of cell therapeutics in BBB regeneration and may also be used for studying stroke.