Intravenous D‑allose administration improves blood glucose control by maintaining insulin secretion in diabetic mice with transplanted islets.

Although pancreatic islet transplantation outcomes have improved, further refinements are required to extend the insulin withdrawal period. The present study examined whether intravenous D-allose administration improves insulin secretion when pancreatic islets are transplanted into type 1 diabetes model mice. Alterations in casual blood glucose levels, intraperitoneal glucose tolerance test (IPGGT) results, the number of apoptotic cells in the engrafted cells, and caspase 3, heme oxygenase 1 and nitric oxide synthase 2 (NOS2) expression in the engrafted cells were examined using the following groups of type 1 diabetic model mice with transplanted pancreatic islets: Mice that received an intravenous injection of D-allose (D-group) and those that received physiological saline as a control (C-group). The mice in the D-group had significantly lower casual blood sugar levels for a longer duration than those in the C-group. Regarding IPGGT, mice treated with D-allose exhibited smaller changes in blood glucose levels compared with untreated mice. Consequently, the incremental area under the curve of glucose in D-allose-treated mice was significantly lower than that in D-allose-untreated mice. No difference was observed in the number of engrafted cells between the groups. NOS2 mRNA expression in the engrafted cells of the D-group tended to be higher than that in the C-group. In conclusion, intravenous administration of D-allose significantly improved hyperglycemia and maintained stable blood glucose levels in type 1 diabetic mice after islet transplantation. Since there was no difference in the number of engrafted cells or apoptotic cells with or without intravenous D-allose administration, D-allose was considered to be effective in maintaining the cellular function of insulin secretion.