Circulating factors present in the sera of naturally skinny people may influence cell commitment and adipocyte differentiation of mesenchymal stromal cells

Figure 2 Mesenchymal stromal cell proliferation, cell cycle analysis, apoptosis, and senescence, following treatment with skinny people and normal people sera. A: Cell proliferation of mesenchymal stromal cells (MSCs) was evaluated by a Quick Cell Proliferation Assay Kit II (Biovision, CA, United States) after treatment with normal people (NP) and skinny people (SP) serum; B: Senescence in MSC cultures. Representative microscopic fields of acid beta-galactosidase positive cells (blue) in NP- and SP-serum treated cultures. In the same panel, the graph shows mean percentage value of senescent cells (± SD, n = 3); C: Representative FACS analysis of MSC apoptosis. The experiments were carried out one week after treatment with sera. The assay allows the identification of early (Annexin V + and 7ADD −) and late apoptosis (Annexin V + and 7ADD +). Nevertheless, apoptosis is a continuous process and we calculated the percentage of apoptosis as the sum of early and late apoptotic cells, to avoid a discretional separation between early and late apoptosis. The histogram show the global percentage of Annexin V-positive cells. Data are expressed with standard deviation (n = 3, ^bP < 0.01); D: Representative Cell cycle FACS analysis of MSCs treted with NP and SP serum. Data are expressed with SD (n = 3). MSCs: Mesenchymal stromal cells; NP: Normal people; SP: Skinny people.