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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 .
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Objective To investigate the influence of VEGF165 gene transfection on the revascularization and transplantation effect of islet grafts.Methods The rat islet cells were transfected with lentivirus containing VEGF165 gene (LV-VEGF165) in vitro,then transplanted to the renal capsule of inbred SD male rats with diabetes mellitus.Islet cells transfected with lentivirus marked with AcGFP1 and no VEGF165 gene were set as null vector control group (LV-AcGFP1 group),individual islet cells as blank control group.VEGF165 expression in vivo and in vitro was detected by ELISA.The islet grafts revascularization degree and islet cell activity were observed by immunohistochemical double staining of insulin and CD31 antibody.Blood glucose and insulin level of rats with diabetes mellitus and survival time of islet grafts were compared.Results The VEGF165 concentrations in the LV-VEGF165 group secreted by islet cells in vivo and in vitro were significantly higher than those in the LV-AcGFP1 group and the blank control group (P＜0.01).Mean microvascular density (MVD) of islet grafts per square millimeter in the LV-VEGF165 group was (24.3 ± 3.7),significantly greater than that in the LV-AcGFP1 group (12.4 ± 2.5) and the blank control group (12.4 ± 2.5) (P＜ 0.01).Insulin staining intensity in the LV-VEGF165 group was also higher than that in the LVAcGFP1 group and the blank control group.The blood glucose and insulin levels in rats with diabetes mellitus analyzed by multivariate analysis in the LV-VEGF165 group were controlled more effectively than those in the LV-AcGFP1 group and the blank control group (P＜0.01).The islet grafts mean survival time (MST) after transplantation in the LV-VEGF165 group was longer than that of the LVAcGFP1 group and the blank control group (P＜0).01).Conclusion The VEGF165 gene transfection to islet cells could promote the revascularization of islet grafts and improve the effect of islet transplantation.
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Objective To investigate the revascular and transplanted effects of islet grafts after co-transplantation with vascular endothelial cells ( ECs) in diabetic rats. Methods The rat ECs and islet cells were isolated and purified, then subcutaneously co-transplanted to the inbred SD male rats with diabetes mellitus, the group of islets transplanted alone, group of phosphate buffered solution, and group of normal rats served as control. Islet grafts revascularization degree, islet cells activity and apoptosis were observed by immunohistochemical double staining of CD31, insulin and factor associated suicide (Fas) antibody. The results of intraperitoneal glucose tolerance test (IPGTT) and intraperitoneal insulin tolerance test (IPITT), the blood glucose and insulin levels of the rats and the survival time of the islet grafts were compared. Results The blood glucose concentrations of IPGTT and IPITT, the blood glucose and insulin levels of rats analyzed by multivariate analysis in the ECs and islets transplantation group were better than those in the islets transplantation alone group (P<0.05). The islet grafts mean survival time of the ECs and islets transplantation group was longer than that of the islets transplantation alone group (P<0.05). On the 7th day after transplantation, mean microvascular density of islet grafts per square millimeter in the ECs and islets transplantation group was 26.4 ± 6.1, significantly greater than that in the islets transplantation alone group 18.3 ± 5.7 (P<0.05). In the ECs and islets transplantation group, insulin staining intensity was higher than that in the islets transplantation alone group (P<0.05), while factor associated suicide(Fas) staining intensity was lower than that in the islets transplantation alone group ( P<0. 05 ). Conclusion Co-transplantation with ECs could promote the revascularization of islet grafts and improve the effect of islet transplantation.
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ABSTRACT:Objective For preparation of vascularized islets , to isolate and culture human adipose derived stem cells , investigate the role of adipose derived stem cells (ADSCs ) in promoting the proliferation and vascularization of human umbilical vein endothelial cells (HUVECs ) co‐cultured in vitro , and explore its mechanism .Methods ADSCs and HUVECs were isolated by collagenase digestion method ,then cultured ,and identified by morphology ,immunofluorescence or multi‐directional differentiation .The co‐culture system of ADSCs and HUVECs was established , HUVECs cultured alone were set up for control group . The proliferation , vascularization and concentration of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (b‐FGF)in the supernatant were compared between the two groups .Results The third generational ADSCs had uniform long spindle fiberous morphology and multi‐directional differentiational function . Immunofluorescence test of surface antigens on ADSCs revealed CD44/CD49d (+ ) ,CD31/CD34 (-) ,on HUVECs CD31/vWF (+ ) . High vascular density was found when co‐cultured in Matrigel of ADSCs and HUVECs than alone of HUVECs .Growth curve shown at days 3 , 4 and 5 of the logarithmic phase , HUVECs count in co‐culture group of ADSCs and HUVECs was (4 .52 ± 0 .31) × 104 ,(7 .18 ± 0 .45) × 104 ,and (8 .23 ± 0 .36) × 104 under indirect co‐culture condition , while that in individual HUVECs group was (2 .71 ± 0 .25) × 104 ,(4 .87 ± 0 .26) × 104 ,and (6 .86 ± 0 .33) × 104 ( P<0 .01) .Population doubling time of HUVECs was shorter in co‐culture group than in individual group .Also ,the OD value of HUVECs was higher in co‐culture group than in individual group when cultured at days 1 ,3 ,5 and 7 ( P<0 .01) .When cultured at days 3 ,7 and 13 ,the concentration of VEGF and b‐FGF in the supernatant was higher in co‐culture group than in individual group ( P< 0 .01 ) . Conclusion ADSCs can promote the proliferation and vascularization of HUVECs in vitro co‐culture conditions by secreting or increasing the HUVECs secretion of VEGF and b‐FGF .
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Objective To isolate and culture human adipose-derived stem cells (hADSCs),investigate the influence of hADSCs on the cellular morphology,survival rate,and function of human islet cells under the in vitro non-contact co-culture conditions,and explore its mechanism.Method hADSCs were isolated by collagenase digestion method,then cultured,and identified by morphology,immunofluorescence and multi-directional differentiation.Adult islet cells were separated and purified by Liberase enzyme and Ficoll 400,then divided into co-culture group and individual group.The cellular growth morphology of islet cells was observed by inverted phase contrast microscope.The survival rate of islet cells,insulin secretory volume,insulin stimulation index and concentration of growth factor in the supernatant were compared between the two groups.Result hADSCs of the third generation showed uniform long spindle fibrocyte-like morphology,and had multi-directional differentiational potentials of osteogenesis and adipogenesis.Immunofluorescence test of surface antigens on hADSCs revealed CD44 + and CD49d +,CD31-,CD34-and CD106-.After 14-day culture,the islet cellular morphology in co-culture group was more intact than that in individual group.The survival rate of islet cells in co-culture group was (82.83 + 2.32) ％,and that in individual group was (53.00 + 2.82) ％ (P＜0.01).Insulin secretory volumes were (23.66 + 2.11) and (7.82 +1.09) mU/L respectively in co-culture group and individual group under high glucose concentration,and 13.22 + 0.77 and 6.40 + 0.44 mU/L respectively under low glucose concentration (P＜0.01 for all).Insulin stimulation index was decreased from 1.67 + 0.10 (at 3rd day) to 1.77 + 0.13 (at 14th day) in co-culture group,and from (1.67 + 0.10) (at 3rd day) to (1.77 + 0.13) (at 14th day) in individual group (P＜0.01).After 14-day culture,the concentrations of HGF,TGF-β,VEGF and bFGF in the supernatant were higher in co-culture group than in individual group (P＜0.01).Conclusion hADSCs were isolated and cultured successfully from adult adipose tissue.They could increase the survival rate and improve the function of islet cells when co-culture with the adult islet cells in vitro through secreting HGF,TGF-β,VEGF and b-FGF.