From ex ovo to in vitro: Xenotransplantation and vascularization of mouse embryonic kidney in microfluidic chip

Abstract

Abstract

Organoids are emerging as a powerful tool to investigate complex biological structures in vitro. Vascularization of organoids is crucial to recapitulate the morphology and function of represented human organ, especially in the case of kidney whose primary function – blood filtration is closely associated with blood circulation. Current in vitro microfluidic approaches have only provided premature vascularization of kidney organoids, whereas in vivo transplantations to animal models are problematic due to ethical problems, with the exception of xenotransplantation to chicken chorioallantoic membrane (CAM). Though CAM could serve as a good environment for vascularization, it could only be used for the time limited by development of the embryo. Here, we propose a novel lab on a chip design that allows organoids of different origin to be cultured and vascularized on CAM, and also allows them to be transferred in vitro conditions when required. Mouse embryonic kidneys cultured on CAM showed enhanced vascularization by intrinsic endothelial cells, and also made connections with the chicken vasculature, as evidenced by blood flowing through them. After chips were transferred in vitro, vasculature inside organoids was successfully maintained. To our knowledge this is the first demonstration of the combination of in vivo and in vitro approaches applied to microfluidic chip design.