BACKGROUND: Advanced glycation endproduct (AGE) formation is thought to contribute to aging and cataract formation in the lens. In this study, we evaluated AGE immunoreactivity in human diabetic (n=14) and nondiabetic (n=31) cataractous lenses in relation to high-molecular-weight (HMW) protein content, which is believed to contribute to the onset of cataract. METHODS: AGE immunoreactivity was detected in alkali-soluble individual lens samples. Competitive ELISA with polyclonal anti-AGE antibody was performed to estimate AGEs. SDS-PAGE was used to detect changes in lens protein composition on the basis of molecular size. RESULTS: Regression analysis of data from nondiabetic lenses showed a significant correlation between lens AGE content and patient age (r=0.665, P<0.001). The curve exhibited exponential regression ( y=0.272.e(0.025x)). The level of nonspecified AGEs measured in diabetic lenses showed an overall increase compared with nondiabetic lenses (4.03+/-1.85 vs 1.78+/-0.71 AU/mg protein, P<0.0078). SDS-PAGE showed the occurrence of HMW proteins in both diabetic and nondiabetic lens samples. However, in diabetic patients, who had a higher level of AGEs, a significantly higher proportion of HMW proteins was also observed. The levels of AGE and percent of HMW aggregates showed a very significant correlation ( r=0.68, P<0.007) in the diabetic group, whereas in nondiabetics the correlation, although positive, did not reach statistical significance. CONCLUSION: The AGE distribution, with a higher proportion in the samples of lenses rich in HMW aggregates, corroborates the hypothesis that the advanced glycation process might have a role in degenerative changes in eye lens, which in diabetic patients occur vigorously and much earlier than in those without diabetes.
BACKGROUND: Advanced glycation endproduct (AGE) formation is thought to contribute to aging and cataract formation in the lens. In this study, we evaluated AGE immunoreactivity in humandiabetic (n=14) and nondiabetic (n=31) cataractous lenses in relation to high-molecular-weight (HMW) protein content, which is believed to contribute to the onset of cataract. METHODS: AGE immunoreactivity was detected in alkali-soluble individual lens samples. Competitive ELISA with polyclonal anti-AGE antibody was performed to estimate AGEs. SDS-PAGE was used to detect changes in lens protein composition on the basis of molecular size. RESULTS: Regression analysis of data from nondiabetic lenses showed a significant correlation between lens AGE content and patient age (r=0.665, P<0.001). The curve exhibited exponential regression ( y=0.272.e(0.025x)). The level of nonspecified AGEs measured in diabetic lenses showed an overall increase compared with nondiabetic lenses (4.03+/-1.85 vs 1.78+/-0.71 AU/mg protein, P<0.0078). SDS-PAGE showed the occurrence of HMW proteins in both diabetic and nondiabetic lens samples. However, in diabeticpatients, who had a higher level of AGEs, a significantly higher proportion of HMW proteins was also observed. The levels of AGE and percent of HMW aggregates showed a very significant correlation ( r=0.68, P<0.007) in the diabetic group, whereas in nondiabetics the correlation, although positive, did not reach statistical significance. CONCLUSION: The AGE distribution, with a higher proportion in the samples of lenses rich in HMW aggregates, corroborates the hypothesis that the advanced glycation process might have a role in degenerative changes in eye lens, which in diabeticpatients occur vigorously and much earlier than in those without diabetes.
Authors: A W Stitt; J E Moore; J A Sharkey; G Murphy; D A Simpson; R Bucala; H Vlassara; D B Archer Journal: Invest Ophthalmol Vis Sci Date: 1998-12 Impact factor: 4.799
Authors: I Dineli Bras; Carmen M H Colitz; Donna F Kusewitt; Heather Chandler; Ping Lu; Anne J Gemensky-Metzler; David A Wilkie Journal: Graefes Arch Clin Exp Ophthalmol Date: 2007-02 Impact factor: 3.117