Gene profile of soluble growth factors involved in angiogenesis, in an adipose-derived stromal cell/endothelial cell co-culture, 3D gel model

Objectives: The aim of this study was to investigate gene expressions of growth factors for angiogenesis, in a three-dimensional (3D) gel populated with adipose-derived stromal cells (ASCs) and endothelial cells (ECs) in co-culture. Materials and methods: The 3D gel, mixed with green fluorescent protein (GFP)-positive ASCs and DsRed-Express-positive ECs, 1:1 ratio, was established in vitro. The phenomenon of angiogenesis was observed using confocal microscopy. To detect gene expressions for growth factor proteins in both ASCs and ECs, transwell co-culture was used, and cell lysate samples were collected at 1, 3, 5 and 7 days. Semi-quantitative polymerase chain reaction (PCR) was conducted to quantify mRNA expressions of the growth factors. Results: Angiogenesis was first observed in the gels by 7 days post-implantation. Over this time in ECs, genes coding for VEGFA/B, IGF-1, HIF-1 alpha, FGF-1/-2 and BMP-5/-7 significantly increased. Meanwhile in ASCs, genes coding for VEGFA/B, IGF-1, HIF-1 alpha, FGF-1/-2 and BMP-6 also were significantly enhanced. In particular, increased amounts of IGF-1 and HIF-1 alpha in both ECs and ASCs were prominent relative to other factors. Conclusions: Contact co-culture with ASCs and ECs at 1:1 ratio, in the 3D gel promoted angiogenesis; non-contact co-culture further confirmed gene expressions for growth factors, VEGFA/B, IGF-1, HIF-1 alpha and FGF-1/-2 in both ASCs and ECs; BMP-5/-7 in ECs and BMP-6 in ASCs were also confirmed. This establishment of growth factor expression seemed to be responsible for enhancement of angiogenesis. This indicates that these factors could be utilized as targets for engineered angiogenesis.