Adipose mesenchymal stem cells promote the function and survival of islet graft during co-transplantation

Objective To explore the function and survival of islet grafts during co-transplantation with adipose mesenchymal stem cells (AMSCs) in diabetic mice. Methods After human AMSCs and islet cells were isolated, purified and then subcutaneously co-transplanted into nude mice with diabetes mellitus. Four groups of AMSCs + islet co-transplantation, islet transplantation alone, phosphate buffered solution (PBS) and normal control mice were designated. Islet cell activity and apoptosis/revascularization degree of islet grafts were observed by immunohistochemical double staining of insulin, factor associated suicide (Fas) and CD31 antibody. The blood glucose and serum insulin levels of mice and the survival time of islet grafts were compared. Results The blood glucose and serum insulin levels of diabetic mice analyzed by multivariate analysis in AMSCs + islet co-transplantation group were better than those in islet transplantation alone group (P<0.05). The mean survival time (MST) of islet grafts was longer in AMSCs + islet co-transplantation group than that in islet transplantation alone group [(81.33±7.58) vs. (58.17±6.91) days] (P<0.05). At Day 7 post-transplantation, insulin staining intensity of islet grafts was higher in AMSCs + islet co-transplantation group than that in islet transplantation alone group while Fas staining intensity of islet grafts was lower. And mean microvascular density (MVD) of islet grafts per square millimeter was higher in AMSCs + islet co-transplantation group than that in islet transplantation alone group [(21.8±5.6) vs. (14.6±4.1)] (P<0.05). Conclusions Co-transplantation with AMSCs may improve the function of islet grafts, prolong its survival and promote its revascularization. Key words: Islet of Langerhans transplantation; Adipose mesenchymal stem cells; Diabetes mellitus