Flow Perfusion Co-culture of Human Mesenchymal Stem Cells and Endothelial Cells on Biodegradable Polymer Scaffolds

In this study, we investigated the effect of flow perfusion culture on the mineralization of co-cultures of human umbilical vein endothelial cells (HUVECs) and human mesenchymal stem cells (hMSCs). Osteogenically precultured hMSCs were seeded onto electrospun scaffolds in monoculture or a 1:1 ratio with HUVECs, cultured for 7 or 14 days in osteogenic medium under static or flow perfusion conditions, and the resulting constructs were analyzed for cellularity, alkaline phosphatase (ALP) activity and calcium content. In flow perfusion, constructs with monocultures of hMSCs demonstrated higher cellularity and calcium content, but lower ALP activity compared to corresponding static controls. ALP activity was enhanced in co-cultures under flow perfusion conditions, compared to hMSCs alone; however unlike the static controls, the calcium content of the co-cultures in flow perfusion was not different from the corresponding hMSC monocultures. The data suggest that co-cultures of hMSCs and HUVECs did not contribute to enhanced mineralization compared to hMSCs alone under the flow perfusion conditions investigated in this study. However, flow perfusion culture resulted in an enhanced spatial distribution of cells and matrix compared to static cultures, which were limited to a thin surface layer.