Glycosaminoglycans urinary excretion as a marker of the early stages of diabetic nephropathy and the disease progression

Abstract

Diabetes mellitus affects the metabolism of several components of extra-cellular matrix, including glycosaminoglycans (GAG). Alterations in the metabolism of GAG may play an important role in the development of diabetic complications. Consequently, the relationship between diabetic nephropathy and urinary GAG excretion has been estimated in 86 diabetic patients (33 type 1 diabetes mellitus (DM), 53 type 2 DM) in comparison to 30 healthy controls (Figure 1). GAG concentration in 24-h urine samples has been determined by precipitation with cetylpyridinum chloride and potassium acetate in ethanol followed by a fluorometric test with 2-Hexadecyl-9H-pyrido(4,3b)indolium Bromide. Diabetic subjects excrete significantly more GAG than the control group (66.47 mg/24 h vs 50.11 mg/24 h). A marked difference in urinary GAG excretion between diabetic patients with nephropathy (74.66 +/- 7.5 mg/24 h) and without nephropathy (50.13 +/- 5.37 mg/24 h) has been detected. With diabetic nephropathy, patients with a longer history of GAG excretion experience an increase. An increased urinary GAG excretion has been detected in patients with microalbuminuria or macroalbuminuria. In conclusion, it can be stated that all patients with DM compared to the control group show an increase in GAG excretion independent of diabetes duration. Urinary GAG excretion positively correlates with the duration of diabetic nephropathy. The assessment of GAG excretion values may be useful for determining the early stages of diabetic nephropathy and the progression of the disease.