The Effect of Age on Human Adipose-Derived Stem Cells

Abstract

Background: Adipose-derived mesenchymal stem cells are a robust, multipotent cell source. They are easily harvested and exhibit promise in a variety of regenerative applications. The purpose of this study was to evaluate the aging impact on adipose-derived mesenchymal stem cells, relating to morphology, senescent properties, growth factor expression, and osteogenesis. Methods: Cells obtained from distinct age groups (infant, adult, and elderly) were cultured. Morphology was examined using microscopy, and cell surface markers were interrogated using flow cytometry. Telomere length was measured using real-time polymerase chain reaction. Expression of pertinent angiogenic and osteogenic growth factors was compared. Osteogenic capability was investigated further by evaluating induction response, and by quantification of mRNA expression of RUNX-2 and osteocalcin. Results: The same isolating ratio of mesenchymal stem cells was derived from each donor, regardless of age. The infant adipose-derived stem cells exhibited elongated spindle morphology and increased telomere length compared with older cells. Angiogenic factors were more highly expressed by infant cells, whereas osteogenic expression was similar among all ages. Response to osteogenic induction was more profound in infant than in older stem cells, as evidenced by alkaline phosphatase and alizarin red staining, as was bone-related gene expression. Conclusions: Adipose-derived mesenchymal stem cells are available across all age groups. Infant-derived cells are morphologically spindle-shaped, with long telomeres, and exhibit enhanced angiogenic and osteogenic capabilities compared with older cells. Conversely, all age groups exhibit similar osteogenic paracrine activity, and the authors posit that clinical applicability is conserved during the adult to elderly period.