[Isolation of urinary heparan sulfate and chondroitin sulfate and their inhibitory activity of calcium oxalate crystal growth].

Urinary heparan sulfate (U-HS) and chondroitin sulfate (U-ChS) were isolated and partially purified using two steps of anion-exchange chromatography (DE-52 and Dowex 1 x 2). Uronic acid content of these urinary glycosaminoglycans (GAGs) and commercial heparan sulfate (C-HS) and chondroitin-6-sulfate (C-C6S) was as follows; U-HS: 22.4%, U-ChS: 32.0%, C-HS: 41.6%, C-C6S: 36.0%. The inhibitory activity of these GAGs on calcium oxalate crystal growth was examined using the crystal-seed system described by Koide et al. The influence of uric acid on the inhibitory activity of the GAGs was also studied. U-HS and U-ChS exhibited nearly equal inhibitory activity to their respective commercial preparations. The inhibitory activity of U-HS was stronger than that of U-ChS. Uric acid suppressed the inhibitory activity of both, and the degree of suppression was stronger in U-ChS than in U-HS. The molecular weight of the urinary GAGs was compared to that of the commercial chondroitin-6-sulfate (C6S; m.w. between 40,000 and 80,000) by gel-filtration using Sephacryl S-300HR. C6S was eluted slightly behind the void volume. U-ChS was eluted much behind C6S. Therefore, the molecular weight of U-ChS was thought to be much smaller than that of C6S. U-HS was eluted into two peaks; the first one at the void volume and the second one between the peaks of C6S and U-ChS. These findings indicate the possibility that part of U-HS exists in the form of proteoglycan.