Serum prorenin levels and diabetic retinopathy in type 2 diabetes: new method to measure serum level of prorenin using antibody activating direct kinetic assay.

AIM To investigate the serum levels of prorenin and its correlation with the severity of diabetic retinopathy (DR). METHODS 248 patients with diabetes and 108 control subjects were divided into four groups: no-DR (n = 146), no proliferative diabetic retinopathy (no-PDR) (n = 78), PDR (n = 24), and controls (n = 108). Serum levels of prorenin from all subjects were measured using the new antibody activating direct kinetic (AAD-PR) assay. The serum prorenin levels were compared among the groups. RESULTS The serum levels of prorenin in the control, no-DR, no-PDR, and PDR groups, respectively, were 109.1 (66.1), 194.6 (160.4), 271.5 (220.3), and 428.4 (358.4) pg/ml (mean (SD)). Prorenin in the PDR group was remarkably high compared with the control and no-DR groups (p<0.0001) and with the no-PDR group (p = 0.002). Serum levels of prorenin increased with increasingly severe retinopathy. No correlation was found between the prorenin level and the duration of disease or HbA(1c). CONCLUSIONS The serum levels of prorenin in patients with PDR were found to be markedly high using the AAD-PR assay. Increased levels of prorenin in diabetes may have an important role in the pathogenesis of DR.