Advanced glycosylation end products in skin, serum, saliva and urine and its association with complications of patients with type 2 diabetes mellitus

The accumulation of advanced glycation end products (AGEs) has a key role in the pathophysiology of diabetes complications. Comparison of AGEs measurement in serum, skin, saliva and urine has not been reported. To compare AGEs in serum, skin, saliva and urine in patients with Type 2 diabetes mellitus, with complications at different stages. We examined 50 patients with Type 2 diabetes mellitus (40 women and 10 men) grouped according to the progression of neuropathy, nephropathy and retinopathy. The AGEs content in serum, skin, saliva and urine was measured by spectrofluorometry HPLC. The patients had a mean age of 56.5 +/- 7.7 yr and 12.8 +/- 6.7 yr since diagnosis. AGEs in skin correlated with years since diagnosis (p = 0.0005). AGEs in serum, skin and saliva increased with the progression of complications, nevertheless, in urine a trend to diminution was found. In the group with end-stage renal disease (ESRD), AGEs in serum increased in greater proportion. In order to account for the decreased AGEs clearance, we corrected the values for creatinine levels, and AGEs in skin gave a better association with complications. The AGEs measurement in skin, serum and saliva are useful to evaluate diabetes complications. AGEs in skin are associated with years since diagnosis of diabetes. Correction for renal function might discriminate AGEs in situ formation from accumulation.