Differentiation of Adipose Tissue-Derived CD34+/CD31-Cells into Endothelial Cells In Vitro

In this study, CD34(+)/CD31(-) progenitor cells were isolated from the stromal vascular fraction (SVF) of adipose tissue using magnetic activated cell sorting. The endothelial differentiation capability of these cells in vitro was evaluated by culturing them in vascular endothelial growth factor (VEGF)-induced medium for 14 days. Viability, proliferation, differentiation, and tube formation of these cells were evaluated. Cell viability study revealed that both undifferentiated and endothelial-differentiated cells remained healthy for 14 days. However, the proliferation rate was higher in undifferentiated cells compared to endothelial-differentiated ones. Upregulation of endothelial characteristic genes (von Willebrand factor (vWF) and VE-cadherin) was observed in 2D culture. However, PECAM (CD31) was only found to be upregulated after the cells had formed tube-like structures in 3D Matrigel culture. These results indicate that adipose-derived CD34(+)/CD31(-) cells when cultured in VEGF-induced medium, are capable differentiation into endothelial-like lineages. Tube formation of the cells started 3 h after seeding the cells on Matrigel and formed more stable and connected network 24 h post-seeding in presence of VEGF. Lay Summary In this work, endothelial differentiation capability of CD34(+)/CD31(-) cells isolated from adipose tissue was evaluated. The results showed that these cells can be successfully differentiated into endothelial cells in vitro in the presence of VEGF. Vascularization is crucial for the survival of the cells and formation of new tissues in engineered tissue constructs. Therefore, finding a proper source of progenitor cells capable of endothelial differentiation is of substantial importance in tissue engineering for the vascularization of large-volume complex tissues. CD34(+)/CD31(-) cells can be easily harvested from adipose tissues in abundance unlike other mesenchymal stem cells such as bone marrow stem cells, which makes them advantageous for vascularization in tissue engineering.