In Vivo Effects of Dermatan Sulfate After Intravenous Injection in Calcium-Oxalate Stone Formers

Abstract

Several reports have suggested that glycosaminoglycans (GAG) inhibit the formation of calcium-containing stones through their restraining effects on growth and aggregation of calcium-oxalate (CaOx) crystals (1). In particular, recent research on the mechanism of GAG inhibition has shown that it takes place because of the binding of the GAG to the crystal surface which results in inhibition of crystal growth and aggregation. These in vitro results have encouraged clinical studies to test different GAG preparations as prophylactic agents in CaOx nephrolithiasis. In the majority of these trials, the drug efficacy has been evaluated by comparing the stone episode rate before and after medication (2). However, very little is known about the influence of these treatments on urine supersaturation with calcium salts, and the type of crystalluria. It was thought of interest, therefore, to study crystals in the urine of patients undergoing treatment with natural polysaccharides. The particular GAG chosen for this in vivo experiment was a multi-sulfated dermatan (MSD) previously characterized for its in vitro inhibitory activity in regard to CaOx crystal growth, anticoagulant activity, and urinary excretion after intravenous (i.v.) administration in normal human volunteers (3).