Exacerbation of diabetic retinopathy following systemic insulin-like growth factor-I. Report of a case

A 19-year-old female had been diagnosed as diabetes mellitus 8 years before. She was identified as type A insulin resistance syndrome. She had hyperinsulinemia and hyperglycemia due to defect in the insulin receptor gene. She was given insulin-like growth factor-I (IGF-I). No retinopathy was present then. The blood sugar level decreased smoothly. Seven months after initiation of the treatment, proliferative retinopathy started to progress. Panretinal photocoagulation failed to prevent disc and retinal neovascularizations. Withdrawal of IGF-I was followed by rapid disappearance of neovascularizations. It appeared that IGF-I decreased the blood sugar level by its insulin-like effect and that it also induced fundus neovascularizations by its growth hormone-like effect on endothelial cells of retinal vessels.