EVALUATION OF THE OSTEOGENIC AND ENDOTHELIAL DIFFERENTIATION POTENTIAL OF SSEA-4 SUBPOPULATION OF ADIPOSE DERIVED STEM CELLS

Human Adipose-Derived Stem Cells (hASCs), an underappreciated source of stem cells, might consist in a new cell poll for tissue engineering (TE) applications, including bone TE. Furthermore, these cells can be harvested in a large number with low morbidity and their developmental plasticity was already proven both in vivo and in vitro. SSEA-4, an early stem cell marker is known to be expressed by hASCs though in a low percentage. Considering the pluripotency of SSEA-4 cells, we examined whether the SSEA-4 + hASCs could differentiate into the endothelial and the osteogenic lineages, aiming to develop a new strategy for promoting the vascularization of bone TE constructs. Analysis by immunocytochemistry and flow cytometry demonstrated the ability of SSEA-4 + hASCs cells to rapidly acquire stable endothelial features (CD31, CD34, CD105 and vWF expression), whilst formation of tubular structures resembling capillary like organization when seeded in Matrigel confirmed their in vitro functional competence. Also, the presence of scavenger receptors for Dil-ac-LDL is consistent with the characteristic of endothelial cells. Furthermore, SSEA-4 + hASCs subpopulation was found suitable for osteogenic differentiation. An upregulation of osteogenensis related genes (osteocalcin-OPN and osteopontin-OCN) was observed which was confirmed also by means on immunocytochemistry. Matrix mineralization was also revealed by Alizarin Red.