Relationship between glycemic control and collagen-linked advanced glycosylation end products in type I diabetes

To evaluate the relationship between glycemic control over a 3-yr period and tissue levels of advanced glycosylation end products. The development of renal failure, blindness, and generalized vascular occlusion continue to be the most serious ravages of diabetes. Tissue glycosylation and AGEs are felt to play an important role in the development of these sequelae, but no data are available on the relationship between AGEs and long-term glycemic control.

We studied 48 subjects with type I diabetes. Glycemic control was determined by mean levels of HbA1, and AGEs were determined on collagenase digests of skin collagen by fluorescence at excitation/emission readings of 335/385 and 370/440 nm.

To evaluate the relationship between glycemic control and AGE levels, control was classified as good (< or = 8.5%), fair (> 8.5% but < or = 10%), or poor (> 10%) on the basis of mean HbA1 levels during 1- and 3-yr periods. Analysis of the mean AGE levels for each level of glycemic control over 1-3 yr showed that AGEs differed significantly across categories of glycemic control (P = 0.04 and 0.003), with the lowest AGE levels associated with good and the highest with poor glycemic control. The relationship also was highly significant when adjusted for age, sex, and duration of diabetes, and when examined by Pearson's correlation coefficients (P = 0.02 and 0.008).

Finding a relationship between glycemic control over 1-3 yr and tissue levels of AGEs suggests that AGEs can be modified and possibly reversed by improved glucose levels.