Urinary factors affecting renal stone disease

This study investigates the physicochemical aspects of calcium oxalate (CaOx) crystallization by the mixed suspension mixed product removal (MSMPR) system -- a continuous crystallization system. Total urinary glycoproteins (GPs) were shown to promote CaOx crystallization. Although whole urinary glycosaminoglyans (GAGs) showed no significant differences on CaOx crystallization, individual GAGs showed that chondroitin sulphate and heparan sulphate promoted the CaOx crystallization while hyaluronan (HA) promoted the formation of smaller CaOx crystals.;Active stone-former (SF) and post-treated SF groups had lower total urinary GAGs excretion but increased proportion of urinary HA than that of the normal controls indicating that urinary GAGs and HA are probably protective/risk factors for the occurrence and recurrence of renal stone disease.;This study suggested the possible events during subclinical CaOx renal stone disease. HA was secreted during CaOx induced cell injury and the injured cells will also secrete IL-1beta as the inflammatory cytokine. This can eventually lead to further HA secretion as well as CD44 expression (HA receptor) that can interact with the HA being secreted for CaOx crystal attachment and retention for stone formation.;Melamine renal stone disease incident in Chinese infants in late 2007 lead to the concern on how melamine affected renal stone disease. The physicochemical nature of melamine in urine was studied by the MSMPR system. Melamine was found to crystallize in normal acidic urinary pH (pH 6.0) and interacted with other lithogenic salts. Presence of melamine significantly enhanced the precipitation of calcium oxalate while the presence of uric acid significantly reduced melamine crystallization.;The main pathogen of urinary tract infection (UTI) -- E. coli on melamine crystallization that common in children was studied and found that it promotes melamine crystallization.;Currently prescribed therapeutic agents including potassium citrate and sodium bicarbonate on melamine crystallization were investigated and found that both of them did significantly reduce melamine crystallization.;Shi Wei is one of the Traditional Chinese medicines (TCM) used for treating renal stones. This study showed that human urine after Shi Wei supplementation had significant acute inhibitory effect on melamine crystallization but the effect was diminished or even levelled off after 1 week supplementation.