Cell specific differences between human adipose-derived and mesenchymal-stromal cells despite similar differentiation potentials.

Stromal cells from bone marrow and adipose tissue are attractive sources of adult progenitors for cell-based therapy. However, whether those cell populations represent intrinsically different cell types is still largely under debate. The aim of this study was to systematically and quantitatively compare adipose-derived stromal cells (ADSC) and bone marrow-derived multipotent mesenchymal-stromal cells (BM-MSC). The quantitative comparison was realized using Taqman Low Density Array, 2D electrophoresis and differentiation functional assays in vitro. Furthermore, cells engineered to express TGFbeta1 were injected into the intra-articular space of mouse knee joints in order to determine whether they were able to form new differentiated tissues in vivo. Our data revealed cell specific differences at transcriptional and proteomic levels between both cell types according to their tissue origin as well as functional differences in their differentiation processes towards adipogenic, osteogenic and chondrogenic programs. Nevertheless, in vitro as well as in vivo ADSC displayed the same ability than MSC to differentiate towards chondrocytes/osteoblasts, comforting the status of both cell sources as promising regenerative cells. In summary, our observations indicate that ADSC and MSC are fundamentally different cell types and differently committed cells.