Relationship of lens advanced glycosylation end products with diabetic retinopathy

Abstract

Background The generation of advanced glycosylation end products (AGEs) is one of the most important characteristics in diabetes mellitus (DM). Its role in diabetic eye disease is still unclear. Objective This study was to investigate the changes of AGE levels in human cataractous lens in diabetic patients and further explore the relationship of lens AGEs with early diabetic retinopathy (DR). Methods This study protocol was approved by Ethic Committee of He Eye Hospital.A cases controlled clinical study was carried out.Forty human nuclei were obtained from 40 cataract patients during the phacoemulcification in He Eye Hospital from August to December 2014, with the nuclear hardness of Ⅲ-Ⅳ grades (Emery grading). The eyes were divided into non-DM (NDM) group and DM group, and the DM group was further divided into non-DR (NDR) group, non-proliferative DR (NPDR) group and proliferative DR (PDR) group.Lens AGE level was quantitatively detected by ELISA. Results The content of pentosidine was (31.90±5.00), (35.83±4.22) and (38.59±5.11)pg/ml, and that of carboxymethyl lysine (CML) was (18.82±3.84), (19.65±2.12) and (23.77±4.73)μg/L, and that of imidazolone was (13.12±2.71), (14.48±2.01) and (15.37±2.74)pg/ml in the NDR group, NPDR group and PDR group, respectively, which was significantly higher than (27.69±1.53)pg/ml, (11.36±1.47)μg/L and (10.21±0.54)pg/ml in the NDM group (all at P 0.05). The positive correlations were found between CML content and pentosidine content (r=0.623, P=0.000), between CML content and imidazolone content (r=0.717, P=0.000) as well as between pentosidine content and imidazolone content (r=0.669, P=0.000). Conclusions The levels of pentosidine, CML and imidazolone in cataractous lens are obviously elevated in the DM patients.The levels of pentosidine and CML in the lens are gradually raised as the aggravation of DR.AGEs might be a potential maker for the assessment of diabetes. Key words: Diabetes mellitus; Advanced glycosylation end product/metabolism; Diabetic retinopathy; Cataract