The Insulin–Like Growth Factor (IGF) System and Type 1 Diabetic Retinopathy During Pregnancy

Abstract

Abstract: : Purpose: To find out whether the levels of insulin–like growth factor–I (IGF–I), insulin–like growth factor binding protein–1 (IGFBP–1), highly phosphorylated insulin–like growth factor binding protein–1 (hpIGFBP–1) and insulin–like growth factor binding protein–3 (IGFBP–3 ) are related to progression of diabetic retinopathy (DR) during pregnancy and postpartum. Methods: In a prospective study of 42 pregnant women with Type 1 diabetes and 9 nondiabetic controls, DR was graded from fundus photographs. Levels of serum total IGF–I, two different phosphoisoform patterns of IGFBP–1 and IGFBP–3 were measured during the first and third trimester of pregnancy and 3 months postpartum. Results: Both the levels of serum total IGF–I (p<0.0001) and IGFBP–3 (p=0.003) were lower in diabetic than in the nondiabetic women during pregnancy and postpartum (repeated measures ANOVA between the groups). Additionally, the IGF–I and IGFBP–3 levels tended to be lower in those diabetic women with more severe DR at baseline than in those with less severe DR. There were no statistically significant differences in levels of IGF–I and IGFBP–3 in those diabetic women with progression of DR compared to those without. No statistical differences appeared in IGFBP–1 phoshoisoform patterns between the groups. Conclusions:In diabetic women, mean serum levels of IGF–1 and IGFBP–3 are lower than in nondiabetic controls during pregnancy and/or postpartum. Since there was no clear connection between insulin–like growth factor system and progression of DR during pregnancy, it is unlikely that these substances mediate the tendency of DR to progress during pregnancy.

Keywords: diabetic retinopathy • retina