Reconstructing human kidney microvasculature for the study of kidney injury

Kidney peritubular capillaries are particularly susceptible to rarefaction and regeneration-limited after exposure to toxins or injuries. Studying these kidney microvessels remain challenging, primarily resulting from difficulties imaging in vivo, as well as isolating and culturing kidney microvascular cells in vitro, in particular in a three-dimensional (3D) microenvironment with proper hemodynamics. Here, we developed methods to isolate, purify, and characterize human kidney peritubular microvascular endothelial cells (hKMECs), and reconstituted a 3D kidney microvasculature in collagen matrix. Compared to other endothelial cells, isolated hKMECs are very sensitive to VEGF for survival and growth, and have a high vasculogenic but low angiogenic potential. Under flow, they formed a fenestrated endothelium with a comprehensive permeability barrier. When exposed to calcineurin inhibitors, hKMECs formed microvessels displayed cell retraction, broken fenestrae, and swollen endothelium, which led to a thrombogenic luminal wall and erythrocytes extravasations into the subendothelial space. Our study recapitulated the human kidney microvascular structure and function, and shed lights on potential mechanistic studies of kidney specific injuries and diseases. Expression levels for human kidney microvascular cells (n=3) were compared to human umbilical vein endothelial cells (n=3)