Impact of Aging on the Characterization of Brown and White Adipose Tissue-Derived Stem Cells in Mice

Adipose tissue enriched with adipose tissue-derived stem cells (ASCs) is often used for stem cell-based therapies. However, the characteristics of ASCs from different types of adipose tissue have varying biochemical and functional properties. We aimed to investigate how age affected the biological and functional characteristics of ASCs from brown (BAT) and white adipose tissue (WAT). ASCs were obtained and cultured from mouse BAT and WAT at different ages: young (2 months of age) and older mice (22 months of age). Mesenchymal markers were characterized by flow cytometry, and cell proliferation, apoptosis, differentiation potential, senescence, and metabolism were then determined. The percentage of WAT was higher in elderly mice, and the percentage of BAT was higher in young mice. All ASC sample phenotypes were characterized as CD29+/CD44+/CD105+/CD45-; the proliferation rate was not statistically different among all age groups. However, the number of senescent cells and the percentage of apoptosis in elderly mouse ASCs were significantly increased, and the ability of osteogenic and lipogenic differentiation was decreased in these same animals. In addition, ASCs from young mice were more inclined to undergo osteogenic differentiation, especially BAT-ASCs, whose gene expression of fat-consuming components was also significantly higher than of WAT-ASCs. The results indicated that ASCs derived from both WAT and BAT possessed different characteristics of fat metabolism and cell differentiation relative to the osteo- and adipolineages. In particular, because BAT-ASCs from young mice contributed to fat consumption, if used for cell grafting, they may potentially be attractive vehicles for treating obesity.