Correlated Research Of The Advanced Glycation End-products In Lens And Diabetes Mellitus

Objective: Advanced glycation end-products,also known as AGEs,are a group of stable and irreversible compounds in the body which is formed by the intermediate products produced by the reaction of the amino part of lysine and the carbonyl part of reducing sugar(such as glucose or other reductive monosaccharide),and some other proteins,macromolecular nucleic acid or some lipids.Studies have shown that the proteins in the crystalline lens in the affection of reducing sugar in the aqueous humor,are prone to such reactions.Therefore,there are AGEs existing in the crystalline lens.Some members of the AGEs have the identity of spontaneously generating fluorescence after stimulating,such as Carboxyethyl lysine(CEL),pentosidine,imidazolone,argpytimidine and so on.In this article,our study mainly focuses on the correlation of the amount of AGEs and diabetes and its conplications.Methods: This article is a cross-sectional study,containing 100 patients aged 50-70 years coming to HE eye hospital in Shenyang.There are 40 cases in the non-diabetic group,and 60 cases in the diabetic group,and the latter one is divided into three subgroups,non-diabetic retinopathy group(NDR),non-proliferating diabetic retinopathy group(NPDR)and proliferating diabetic retinopathy group(PDR)respectively.We make a quantitative detection of the autofluorescence of the crystalline lens using the lens autofluorescence biomicroscopy(Clearpath DS120,Freedom Meditech,Inc,San Diego,CA,USA),and a comparison test between groups and subgroups.Results: The Hb A1 c values in the DM group is significantly increased comparing with the NDM group(the mean±SD,respectively,5.485±0.803 and 7.683±1.533,P=0.000).And in the subgroup(NDR group,NPDR group and PDR group,the mean±SD is respectively 6.995±1.437,7.605±1.073 and 8.450±1.718).The difference of independent sample T test between NDM group and NDR group(P=0.003),between NDM group and NPDR group(P=0.000),between NDM group and PDR group(P=0.000),between NDR group and PDR group(P=0.006)are significant.The level of the autofluorescence of the advanced glycation end-products in the crystalline lens is significantly increased in diabetic group comparing with non-diabetic group(the mean±SD,respectively,0.322±0.062 and 0.159±0.032,P=0.000).And in three subgroup in diabetic patients,the level significantly increases in turn(the mean±SD respectively,0.256±0.024,0.319±0.013 and 0.394±0.035,P=0.000).The correlation of glycosylated hemoglobin A1 c and the amount of autofluorescence is significant(correlation coefficient r=0.654,P=0.000).Conclusion: The amount of the autofluorescence of the advanced glycation end-products in the crystalline lens shows significant correlation with the classification of diabetic retinal complications,and is related with the amount of glycosylated hemoglobin A1 c.This is a noninvasive and repeatable test,which can be used in early diagnosis of diabetes and in measuring the risk of diabetes progression.