Porous membranes promote endothelial differentiation of adipose-derived stem cells and perivascular interactions

Abstract

Efforts to create physiologically relevant microenvironments for cell differentiation have led to the creation of three-dimensional (3D) support matrices with varying physical and chemical properties. In an effort to simplify the complexity of these matrices, while maintaining their unique permeable nature, we investigated the culture and differentiation of adipose-derived stem cells (ADSCs) on porous membranes. Membranes offer many of the benefits of a 3D matrix, but simplify cell seeding, imaging, analysis and post-differentiation recovery. After inducing the differentiation of ADSCs into endothelial cells (ECs), the cells cultured on porous substrates produce more branch points and greater tube length in angiogenesis assays compared to the cells cultured on non-porous controls. While we confirm that ADSCs can be induced with vascular endothelial growth factor to express endothelial adhesion molecule CD31 (PECAM-1), only when co-cultured across a membrane with human umbilical vein endothelial cells (HUVECs), do a subset of ADSCs show appropriate CD31 distribution along cell boundaries. Others have recently described that mesenchymal stem cells derive from perivascular cells including pericytes, which are known to wrap circumferentially around microvessels. We used ultrathin porous membranes to permit limited physical interactions between polarized HUVECs and ADSCs. In this arrangement, we found that the majority of ADSCs aligned perpendicular to the polarized HUVECs even though contact between the cell types was limited by pores less than 500 nm in diameter. Together, this ADSC pericyte behavior in combination with the ability to differentiate into ECs shows the potential versatility of ADSCs in the engineering of vascular networks. © 2014 Biomedical Engineering Society.