High glucose induces early senescence in adipose-derived stem cells by accelerating p16 and mTOR

Abstract

Introduction: The senescence of stem cells is the primary reason that causes aging of stem cell-containing tissues. Some hypotheses have suggested that high glucose concentration in diabetic patients is the main factor that causes senescence of cells in those patients. This study aimed to evaluate the effects of high glucose concentrations on the senescence of adipose-derived stem cells (ADSCs).
 Methods: ADSCs were isolated and expanded from human adipose tissues. They were characterized and confirmed as mesenchymal stem cells (MSCs) by expression of surface markers, their shape, and in vitro differentiation potential. They were then cultured in 3 different media- that contained 17.5 mM, 35 mM, or 55 mM of D-glucose. The senescent status of ADSCs was recorded by the expression of the enzyme beta-galactosidase, cell proliferation, and doubling time. Real-time RT-PCR was used to evaluate the expression of p16, p21, p53 and mTOR.
 Results: The results showed that high glucose concentrations (35 mM and 55 mM) in the culture medium induced senescence of human ADSCs. The ADSCs could progress to the senescent status quicker than those cultured in the lower glucose-containing medium (17.5 mM). The senescent state was related to the up-regulation of p16 and mTOR genes.
 Conclusion: These results suggest that high glucose in culture medium can trigger the expression of p16 and mTOR genes which cause early senescence in ADSCs. Therefore, ADSCs should be cultured in low glucose culture medium, or normal glucose concentration, to extend their life in vitro as well as in vivo.