['To investigate islet graft survival and function after co-culture and co-transplantation with vascular endothelial cells (ECs) in diabetic rats.', 'We isolated ECs, and assessed the viability of isolated islets in a group of standard culture and a group of co-culture with ECs. Then we put the diabetic rats in 4 groups: an islet transplantation group, an islet graft with EC transplantation group, an EC transplantation group, and a PBS control group. Blood glucose and insulin concentrations were measured daily. Cell morphology and cell markers were investigated by immunohistochemical staining and electron microscope.', 'Normal morphology was shown in more than 90% of AO/PI staining positive islets while co-cultured with ECs for 7 days. Insulin release assays showed a significantly higher simulation index co-culture except for the first day (P<0.05). There was a significant difference in concentrations of blood glucose and insulin among the 4 groups after 3 days after the transplantation (P<0.05).'] Do [ Endothelial cells promote islet survival and function ]?