TUBULAR-LIKE STRUCTURE FORMATION OF HUVECS IN A CO-CULTIVATION SYSTEM WITH HMSCS

Stefanie Thoms, Valerie Nkolo Oyono, Rebecca Jonczyk, Thomas Scheper and Cornelia Blume

Institute of Technical Chemistry, Leibniz Universität Hannover, Hannover, Germany

Abstract

Tissue engineering is limited by the lack of vascular networks that ensure a sufficient supply of nutrients and oxygen. Vascular networks consist of endothelial cells that form the inner wall of the vascular channels. In our work, the strategy of generating vascular-like structures is based on co-cultivation of endothelial cells with human mesenchymal adipose-tissue derived stem cells (hMSCs) in a transwell system. Thereby, stem cells are considered as homing cells that influence tubular-like structure formation of HUVECs by production of angiogenetic factors. Parameters like initial cell density of HUVECs, serum concentration, starvation, beginning of co-cultivation after seeding the cells and the use of medium conditioned by stem cells under hypoxic and normoxic conditions were tested in the co-cultivation process. A strong tubular-like structure formation of HUVECs was determined after 7 days of co-cultivation with a higher initial cell density of 8000 HUVECs/cm², a high concentration of 7 % human serum. Co-cultivation was started 3 days after cell seeding. Moreover, screening of the supernatant and lysed cells resulted in an increased expression of selected angiogenic factors such as VEGF-A, VEGFR-1 or the adhesion factor PECAM-1. In vitro formation of tubular-like structures is an important step to develop vascularized tissue engineered grafts.

Keywords: Tissue engineering, vascularization, tubular-like structures, endothelial cells, co-cultivation, hMSCs.