Influence of donor age on the differentiation and division capacity of human adipose-derived stem cells

BACKGROUND Human adipose-derived stromal/stem cells (hASCs) are one of the most useful types of mesenchymal stromal/stem cells, which are adult multipotent cells with great therapeutic potential for the treatment of several diseases. However, for successful clinical application, it is critical that high-quality cells can be obtained. Diverse factors seem to be able to influence cell quality and performance, especially factors related to donors' intrinsic characteristics, such as age. Nevertheless, there is no consensus regarding this characteristic, and there is conflicting information in the literature. AIM To investigate the growth kinetics and differentiation potential of adipose-derived stem cells isolated from the lipoaspirates of elderly and young donors. METHODS hASCs were harvested from liposuctioned adipose tissue obtained from female donors (aged 20-70 years). Cells were distributed into two groups according to age range: old hASCs (oASCs, >= 55 years, n = 9) and young hASCs (yASCs, <= 35 years, n = 9). For each group, immunophenotypic characterization was performed by flow cytometry. Population doubling time was assessed over seven days. For adipogenic potential evaluation, lipid deposits were assessed after 7 d, 14 d and 21 d of adipogenic induction. Osteogenic potential was verified by analyzing cell mineralization after 14 d, 21 d and 28 d of osteogenic induction. mRNA expression of PPAR.2, CEBPA and Runx2 were detected by quantitative reverse transcription polymerase chain reaction. RESULTS hASCs were successfully obtained, cultured, and grouped according to their age: yASCs (26.33 +/- 4.66 years old) and oASCs (64.78 +/- 4.58 years old). After maintenance of the cells in culture, there were no differences in morphology between cells from the young and old donors. Additionally, both groups showed classical immunophenotypic characteristics of mesenchymal stem/stromal cells. The average doubling time indicated that yASCs (4.09 +/- 0.94 d) did not significantly differ from oASCs (4.19 +/- 1.29 d). Concerning differentiation potential, after adipogenic and osteogenic induction, yASCs and oASCs were able to differentiate to greater levels than the noninduced control cells. However, no differences were found in the differentiation efficiency of yASCs and oASCs in adipogenesis or osteogenesis. Additionally, the mRNA expression of PPAR gamma 2, CEBPA and Runx2 were similar in yASCs and oASCs. CONCLUSION Our findings suggest that age does not seem to significantly affect the cell division or adipogenic or osteogenic differentiation ability of adipose-derived stem cells isolated from lipoaspirates.