In Vitro self-organized three-dimensional model of the blood-brain barrier microvasculature

The blood-brain barrier (BBB) protects the human brain from external aggressions. Despite it great importance, very few in vitro models of the BBB reproducing its complex organization are yet available. Here we fabricated such a three-dimensional (3D) self-organized in vitro model of BBB microvasculature by means of collagen microfibers (CMF) and fibrin gel combination. The interconnected fibres supported human brain microvascular endothelial cell migration and the formation of a capillary-like network with lumen diameter close to in vivo values. Fibrin, a protein involved in blood vessel repair, favored further the 3D conformation of brain microvascular endothelial cells, astrocytes and pericytes, ensured gel cohesion and avoided shrinkage. The maturation of the BBB microvasculatures network was stimulated by both the CMF and the fibrin in the hydrogel. Expression of essential tight junction proteins, carriers and transporters were validated in regards to bidimensional simple coculture. The volume of gel drops was easily tunable to fit in 96 well-plates. D-Mannitol cytotoxicity and impacts on microvascular network were evaluated, as an example of the pertinence of this 3D BBB capillary model for screening applications.