Erythrocyte glucose consumption in insulin-dependent diabetes: effect of metformin in vitro

Erythrocyte glucose consumption in red blood cells from healthy donors or insulin-dependent diabetics with stable glycemia was measured using the 2-deoxyglucose technique. Data showed that the formation of glucose-6P was severely impaired in diabetic red blood cells in both normo- and hyperglycemic incubation conditions. This defect seems to be inherent to the disease. Coincubation with Metformin (6.4 ug/ml) did not modify the G6P levels in RBCs from healthy donors and in RBCs from diabetics when incubated in normoglycemic conditions. However, when diabetics RBCs were incubated in a hyperglycemic medium, addition of Metformin strongly improved the intracellular levels of G6P. The underlying mechanism for the defect and the correction by Metformin remains to be determined. This study shows that also red blood cells may be involved in the failure of glucose homeostasis in diabetes and thus this may represent an additional target for therapy.