Relation between insulin secretory capacity and microangiopathy in young diabetic patients in Bangladesh

Abstract

The pathogenesis of diabetic retinopathy is still unclear. The relative role of duration of diabetes, glycemic and insulinemic status in the etiopathogenesis of retinopathy is to be clearly understood. Hypertension, hyperlipidemia, pregnancy and age at diagnosis have been thought to be factors associated with diabetic retinopathy. Taking advantage of the availability of a group of young lean, normotensive and generally normolipidemic subjects in Bangladeshi population, the present study was undertaken to investigate the relationship between insulin secretory capacity and microvascular damage in the pathogenesis of diabetic retinopathy. A total number of 91 diabetic subjects, diabetes diagnosed before the age of 30 years, were recruited form the out-patient Department, BIRDEM Hospital. Diabetic subjects recruited were new- to previously diagnosed cases with duration of diabetes around 8 years. Insulin secretory capacity was assessed by C-peptide and C-peptide was estimated by ELISA method. Urinary albumin was measured by Immunoturbidetric methods. The subjects were grouped on the basis of duration of diabetes and presence (DR) and absence (NDR) of diabetic retinopathy. Subjects were also divided on the basis of albumin-creatinine ratio (ACR) level. ACR level was observed sharply increased with the duration of diabetes and showed a peak after 8 years. In the ACR positive cases 95.25% of diabetic patient had retinopathy. Both retinopathic and ACR positive subjects had low insulin secretory capacity as evident by absolute C-peptide level and C-peptide glucose ratio. Retinopathy was found increased with generalized vasculopathy. Both microvasculopathy and retinopathy seemed to occur at around 8 years. Insulin secretory capacity in particular seemed to have predominant determinant effect in the etiopathogenesis of diabetic retinopathy.