ROLE OF ADVANCED GLYCATION END-PRODUCTS (AGE) IN LATE DIABETIC COMPLICATIONS

To evaluate accumulation of advanced glycation end-products (AGE) in d iabetes and its possible correlation with late diabetic complications, AGE levels were measured by spectrofluorimetry in eye lens and sciati c nerve proteins and isolated tail tendon collagen of rats with experi mental diabetes of 3- and 6-month duration. The values obtained were c ompared to those from age-matched control rats and correlated with cat aract presence and somatosensory evoked potential (SEP) alterations. D iabetic animals had increased AGE levels in all tissues at both times; cataract developed in 29% of diabetic rats at 3 months and in 57% at 6 months; SEP conduction velocity was reduced in diabetic animals both at 3 (54.5 +/- 1.8 S.E.M. m/s vs. 73.9 +/- 1.0, P < 0.0001) and 6 mon ths (59.5 +/- 1.4 vs. 71.5 +/- 1.6, P < 0.0001) from diabetes inductio n. No eye lens AGE level differences were observed when cataract prese nce was considered. Interestingly, in diabetic rats, increased sciatic nerve AGE levels were associated with reduced SEP. These data show th at: (1) AGE levels are increased as early as 3 months from development of hyperglycemia; (2) other factors, in addition to an enhanced rate of fluorescent AGE formation, might play important roles in the pathog enesis of diabetic cataract; (3) increased peripheral nerve AGE levels are associated with SEP alterations.