In vitro model of a vascular stroma for the engineering of vascularized tissues

A major problem for the in vitro engineering of larger tissue equivalents l ike those required in reconstructive surgery is the lack of solutions for s ufficient nutrition and oxygenation. The starting point of our investigatio n was the question of whether the principles of in vitro angiogenesis can b e applied and utilized for tissue engineering. A soft tissue model was deve loped, consisting of human adipose tissue stromal cells and umbilical vein endothelial cells in a fibrin-microcarrier scaffold. Capillary-like structu res were visualized using UEA-I-lectin labelling and confocal laser scannin g microscopy. Length of capillary-like structures was measured in an image analysis system. Under serum-free culture conditions, maintenance of capill ary-like structures was significantly increased in comparison to serum-cont aining cultures. The application of vascular endothelial growth factor (VEG F) resulted in a high initial angiogenic response; long-term stabilization of capillary-like structures could not be achieved, however supplementation with IGF-1 resulted in the highest values and the slightest decrease in le ngth of capillary-like structures, so that the results could be interpreted as an improved stabilization.