Tracking Human Adipose‐Derived Stem Cells (hASCs) in an Ex Vivo Microvascular Network Model

Abstract

Models that mimic angiogenesis are valuable for the investigation of underlying mechanisms and the pre-clinical development of therapies. We have recently demonstrated that the rat mesentery culture model offers the potential for time-lapse investigation of mechanistic cell–cell interactions at specific locations across intact blood and lymphatic microvascular networks ex vivo. The objective of this study was to demonstrate the capability of the rat mesentery culture model to track exogenously delivered human adipose-derived stem cell (hASC) migration and differentiation dynamics within an intact microvascular network. RFP-transfected hASCs were seeded onto the harvested adult Wistar rat mesenteric tissues and cultured for 3 or 5 days. In separate studies, RFP-transfected hASCs were pre-positioned in “cell spots” (~40 cells per spot) via laser direct write cell printing on the tissues and cultured up to 5 days. Lectin labeling of endothelial cells on day 0 and later time points enabled time-lapse imaging of cells during angiogenesis. For both cell delivery approaches, cells integrated within the tissues and displayed elongated morphologies. A subset of hASCs adopted a perivascular location typical of vascular pericytes. The laser direct write printing studies confirmed cell migration. Our results establish an ex vivo model for evaluating the initial differentiation, growth and migration dynamics of stem cells in an intact microvascular network scenario.