What are the main inhibitors of renal stone formation, and how do they work?
Inhibitors include urinary citrate, pyrophosphate, magnesium, nephrocalcin, uropontin, glycosaminoglycans, and Tamm-Horsfall protein. Most inhibitors bind crystal precursors; for example, citrate binds calcium, making it less available to bind to oxalate. Inhibitors improve solubility and impair precipitation, nucleation, crystal growth, or aggregation. They also compete with stone precursor minerals, such as calcium oxalate, for binding to the apical surfaces of epithelial cells and inhibit epithelial cell adhesion and internalization of calcium oxalate crystals. Finally, inhibitors impair stone precursor transformation into a focus for crystallization and stone growth.