Age-related changes of p75 Neurotrophin receptor-positive adipose-derived stem cells

Background: The existence of multipotent stem cells in subcutaneous adipose tissue has been reported. We previously confirmed that p75 neurotrophin receptor (p75NTR; CD271)-positive cells in subcutaneous adipose tissue possessed multipotency, although changes of the characteristics in p75NTR-positive adipose-derived stem cells (ASCs) with aging remain unclear. Objective: To investigate the effect of aging on p75NTR-positive ASCs. Methods: The number of p75NTR-positive ASCs in subcutaneous adipose tissue of ICR mice aged 3-24 weeks was analyzed by immunostaining and flow cytometry. Subsequently, the cells were isolated and their ability to attach to the cell culture dish, proliferation rate (doubling time) and the expression of senescence-associated β-galactosidase (SA-β gal), a cellular senescence marker, were assessed. Age-related changes in the differentiation potential of p75NTR-positive cells in adipogenic, osteogenic, chondrogenic and myogenic lineage were also investigated. Results: The number of ASCs per unit of tissue weight in adipose tissue and the attachment rate of isolated cells decreased with aging. No difference in the cell proliferation rate and the percentage of SA-β gal-positive cells was detected. Although the efficacy of differentiation into adipogenic and osteogenic lineages slightly decreased with aging, the differentiation potential into chondrogenic and myogenic lineages was not changed. Conclusion: The number of ASCs per unit of tissue weight decreased in aged mice. However, the cells possessed proliferation and differentiation potentials almost equal to those of young mice even though the differentiation potentials showed a tendency of decrease. These results raise the possibility that stem cell functions, self-renewal and multipotency, are maintained regardless of aging.