Bone marrow- and subcutaneous adipose tissue-derived mesenchymal stem cells: differences and similarities.

Bone marrow (BM) and subcutaneous adipose tissue (Ad) are both considered being prospective sources of MSC for therapeutic applications. However, functional properties and therapeutic efficacy of MSC derived from different tissues of the same patient are still poorly investigated. In our study, BM-MSC and F-MSC cultures from 43 adult donors were evaluated in successive passages for immunophenotype, secretion of VEGF, SDF1, MCP1, IL6 and TGFβ1, frequency of colony-forming units (CFU-F), frequency of adipo- and osteo-progenitors (CFU-Ad, CFU-Ost), and for onset of in vitro replicative senescence. We have demonstrated that at early passages (P2-P4 or up to 14-15 in vitro population doublings) BM- and Ad- derived MSC cultures are comparable in such important characteristics as proliferation rate (population doubling time: 3.4±0.2% in BM-MSC, 3±0.3% in F-MSC), clonogenity (CFU-F frequency: 32±5% in BM-MSC, 31±5% in F-MSC), differentiation potential (CFU-Ad frequency: 10.4±2% in BM-MSC, 13±3% in F-MSC; CFU-Ost frequency: 18.5±5.5% in BM-MSC, 18±5% in F-MSC), but differ significantly in abundance of CD146⁺ fraction within the sample (25±5% in BM-MSC, 7±3% in F-MSC) and in a level of VEGF, SDF-1, MCP1 and TGFβ1 secretion. We have also demonstrated that BM-MSC enter senescence after P3-4 while most of F-MSC did not show senescence features up to P6-8. Together, these data demonstrate that specific properties of MSC from different sources should be always taken into account, when developing and optimizing the specific protocols for MSC expansion and evaluation for each particular clinical application.