The Urinary Excretion of Glycosaminoglycans in Non-Insulin Dependent Diabetics

Abstract

The urinary excretion rate of glycosaminoglycans (GAGs) was measured in timed-overnight urine samples from 154 non-insulin dependent diabetics (NIDDM) without overt diabetic nephropathy, and in those of 45 normal controls, using the dye-binding method of Alcian-blue 8GX. Albumin excretion rate (AER) was also measured in the same samples. The GAGs excretion rate in NIDDM was significantly higher than in the controls (p<0.005). In microalbuminuric patients (20<AER<200μg/min), GAGs excretion was significantly higher than in normoalbuminuric patients (AER<20μg/min). GAGs excretion rate did not correlate with diabetic duration, Hb Ai c levels, and blood pressure, however it directly correlated with creatinin clearance in normoalbuminuric patients without retinopathy. GAGs excretion in normoalbuminuric patients with proliferative relinopathy was significantly higer than that in normoalbuminuric patients with other stages of diabetic retinopathy (p<0.001). These results suggest that an abnomal metabolism of GAGs occurred in NIDDM with microangiopathy, and that an increase in GAGs excretion in microalbuminuric patients might reflect a reduction of anionic charge in the glomerular basement membrane. Further study is required to determine the effect of long-term metabolic control on GAGs excretion.