Non-insulin-dependent diabetes mellitus-associated changes in serum glycosaminoglycans

It is known that diabetes mellitus affects the metabolism of several components of extracellular matrix, including glycosaminoglycans (GAGs). These changes are believed to play an important role in the development of diabetic complications. An altered GAG metabolism is one of the main causes of diabetes-associated vascular pathology. For these reasons it was decided to evaluate the changes in serum GAGs of patients with non-insulin-dependent diabetes mellitus (NIDDM). The GAGs were isolated from the serum of healthy subjects (control group) and diabetic patients (investigated groups). They were submitted to electrophoretic fractionation and quantitative evaluation by enzymatic methods. It was found that NIDDM is accompanied by a distinct increase in the concentration of serum GAGs. First of all, the concentrations of chondroitin sulphates (ChS) and dermatan sulphate (DS) were found to be elevated. These alterations were much more distinct in patients with a poor metabolic control than in those with a good metabolic control. An increase in ChS and DS fractions was accompanied by nonsignificant elevation in heparan sulphate/heparin (HS/H) level in patients with good metabolic control and by a distinct decrease in HS/H concentration in poorly controlled diabetic subjects. Hyaluronic acid (HA) (undetectable in healthy subjects and in patients with a good metabolic control) was found in trace amounts in poorly controlled diabetic individuals. The obtained data allow to conclude that NIDDM-associated disturbances of tissue GAGs metabolism result in significant alterations in serum GAG composition.