Rapid Induction of Osteogenic Markers in Mesenchymal Stem Cells by Adipose-Derived Stromal Vascular Fraction Cells.

BACKGROUND/AIMS: Stromal vascular fraction (SVF) cells are a mixed cell population, and their regenerative capacity has been validated in various therapeutic models. The purpose of this study was to investigate the regenerative mechanisms utilized by implanted SVF cells. Using an in vitro co-culture system, we sought to determine whether SVF implantation into impaired tissue affects endogenous mesenchymal stem cell (MSC) differentiation; MSCs can differentiate into a variety of cell types, and they have a strong regenerative capacity despite their low numbers in impaired tissue.

METHODS: Adipose-derived SVF cells obtained from four donors were co-cultured with bone marrow-derived MSCs, and the differential expression of osteogenic markers and osteogenic differentiation inducers over time was analyzed in mono-cultured MSCs and MSCs co-cultured with SVF cells.

RESULTS: The co-cultivation of MSCs with SVF cells significantly and mutually induced the expression of osteogenic-specific markers via paracrine and/or autocrine regulation but did not induce adipocyte, chondrocyte or myoblast marker expression. More surprisingly, subsequent osteogenesis and/or comparable effects were rapidly induced within 48 h.

CONCLUSION: To the best of our knowledge, this is the first study in which osteogenesis and/or comparable effects were rapidly induced in bone marrow-derived MSCs and adipose-derived SVF cells through co-cultivation. Our findings suggest that the positive effects of SVF implantation into impaired bone may be attributed to the rapid induction of MSC osteogenesis, and the transplantation of co-cultured and preconditioned SVF cells and/or MSCs may be more effective than the transplantation of untreated cells for the treatment of bone defects.