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Sirtuin 3 (SIRT3) is a deacetylase important for antioxidant protection, cell longevity, and aging. We hypothesized that SIRT3 improve oxidative resistance of aged cells and improve cell therapy in aged patients. In vitro , the proliferation and oxidative resistance of human mesenchymal stem cells (hMSCs) significantly declined with age. The expression and activity of antioxidant enzymes, including catalase (CAT) and manganese superoxide dismutase (MnSOD), increased after transfection of SIRT3 in hMSCs from older donors (O-hMSCs). The protein level of Forkhead box O3a (FOXO3a) in nucleus increased after SIRT3 overexpression. The antioxidant capacity of O-hMSCs increased after SIRT3 overexpression. 3-Amino-1,2,4-triazole (3-AT, CAT inhibitor) or diethyldithiocarbamate (DETC, SOD inhibitor) that was used to inhibit CAT or SOD activity significantly blocked the antioxidant function of SIRT3. When two inhibitors were used together, the antioxidant function of SIRT3 almost disappeared. Following myocardial infarction and intramyocardial injections of O-hMSCs in rats in vivo , the survival rate of O-hMSCs increased by SIRT3 transfection. The cardiac function of rats was improved after SIRT3-overexpressed O-hMSC transplantation. The infarct size, collagen content, and expression levels of matrix metalloproteinase 2 (MMP2) and MMP9 decreased. Besides, the protein level of vascular endothelial growth factor A and vascular density increased after cell transplantation with SIRT3-modified O-hMSCs. These results indicate that damage resistance of hMSCs decline with age and SIRT3 might protect O-hMSCs against oxidative damage by activating CAT and MnSOD through transferring FOXO3a into nucleus. Meanwhile, the therapeutic effect of aged hMSC transplantation can be improved by SIRT3 overexpression.

Stem cell transplantation is nearly available for clinical application in the treatment of ischaemic heart disease (IHD), where it may be joined traditional methods (intervention and surgery). The angiogenic ability of seed cells is essential for this applicability. The aim of this study was to reveal the presence of CD34+ angiogenic stem cells in human decidua at the first trimester and to use their strong angiogenic capacity in the treatment of IHD. In vitro, human decidual CD34+ (dCD34+) cells from the first trimester have strong proliferation and clonality abilities. After ruling out the possibility that they were vascular endothelial cells and mesenchymal stem cells (MSCs), dCD34+ cells were found to be able to form tube structures after differentiation. Their angiogenic capacity was obviously superior to that of bone marrow mesenchymal stem cells (BMSCs). At the same time, these cells had immunogenicity similar to that of BMSCs. Following induction of myocardial infarction (MI) in adult rats, infarct size decreased and cardiac function was significantly enhanced after dCD34+ cell transplantation. The survival rate of cells increased, and more neovasculature was found following dCD34+ cell transplantation. Therefore, this study confirms the existence of CD34+ stem cells with strong angiogenic ability in human decidua from the first trimester, which can provide a new option for cell‐based therapies for ischaemic diseases, especially IHD. [ABSTRACT FROM AUTHOR]

Sirtuin 3 (SIRT3) is a deacetylase important for antioxidant protection, cell longevity, and aging. We hypothesized that SIRT3 improve oxidative resistance of aged cells and improve cell therapy in aged patients. In vitro, the proliferation and oxidative resistance of human mesenchymal stem cells (hMSCs) significantly declined with age. The expression and activity of antioxidant enzymes, including catalase (CAT) and manganese superoxide dismutase (MnSOD), increased after transfection of SIRT3 in hMSCs from older donors (O-hMSCs). The protein level of Forkhead box O3a (FOXO3a) in nucleus increased after SIRT3 overexpression. The antioxidant capacity of O-hMSCs increased after SIRT3 overexpression. 3-Amino-1,2,4-triazole (3-AT, CAT inhibitor) or diethyldithiocarbamate (DETC, SOD inhibitor) that was used to inhibit CAT or SOD activity significantly blocked the antioxidant function of SIRT3. When two inhibitors were used together, the antioxidant function of SIRT3 almost disappeared. Following myocardial infarction and intramyocardial injections of O-hMSCs in rats in vivo, the survival rate of O-hMSCs increased by SIRT3 transfection. The cardiac function of rats was improved after SIRT3-overexpressed O-hMSC transplantation. The infarct size, collagen content, and expression levels of matrix metalloproteinase 2 (MMP2) and MMP9 decreased. Besides, the protein level of vascular endothelial growth factor A and vascular density increased after cell transplantation with SIRT3-modified O-hMSCs. These results indicate that damage resistance of hMSCs decline with age and SIRT3 might protect O-hMSCs against oxidative damage by activating CAT and MnSOD through transferring FOXO3a into nucleus. Meanwhile, the therapeutic effect of aged hMSC transplantation can be improved by SIRT3 overexpression. [ABSTRACT FROM AUTHOR]