Influence of in vitro cultivation on the integration of cell-matrix constructs after subcutaneous implantation

Dynamic cultivation of scaffolds loaded with undifferentiated stem cells can lead toward osteogenic differentiation in vivo. The aim of this study was to examine the influence of different in vitro cultivation setups on the integration of cell-matrix constructs after subcutaneous implantation. Human mesenchymal stem cells (hMSC) were inoculated on clinically approved scaffolds. These cell-matrix constructs were then cultured under static (12 hours or 14 days) or dynamic (14 days) conditions, followed by paravertebral subcutaneous implantation in athymic nude mice. After 2 weeks and 12 weeks the constructs and selected organs were harvested for histological evaluation, and qualitative and quantitative polymerase chain reaction (PCR). Histological analysis showed good integration of cell-matrix constructs independent of culture conditions and a differential effect of static and dynamic in vitro culture on fat cell formation in vivo. Human DNA (hDNA) was detected in explanted cell-matrix constructs at all time points with a significant decrease in human cells on the constructs compared to the initial amount of cells seeded. No hDNA was detected in the explanted organs. In conclusion, we could prove the survival of hMSC on scaffolds after in vitro cultivation and consecutive implantation in vivo. While the amount of adipose tissue increased after static cultivation, we could not achieve osteogenic differentiation.