title: Advanced glycation endproducts in human diabetic and non-diabetic cataractous lenses.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Ophthalmology, Zagreb University Hospital Center, Zagreb, Croatia.
authors.forename: Rajko
authors.initials: R
authors.lastname: Pokupec
authors.forename: Miro
authors.initials: M
authors.lastname: Kalauz
authors.forename: Niksa
authors.initials: N
authors.lastname: Turk
authors.forename: Zdenka
authors.initials: Z
authors.lastname: Turk
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002386:Cataract / Q000378:metabolism*; D003920:Diabetes Mellitus / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D017127:Glycation End Products, Advanced / Q000378:metabolism*; D006801:Humans; D007908:Lens, Crystalline / Q000378:metabolism*; D008297:Male; D008875:Middle Aged
chemical_list: D017127:Glycation End Products, Advanced