What are the promoters of renal stone formation? Promoters of renal stone formation are poorly characterized but are believed to be primarily urinary mucoproteins and glycosaminoglycans. Under certain conditions, promoters enhance the formation of renal stones.
What is nephrocalcin, and what role does it play in the formation of renal stones? Nephrocalcin is an anionic protein produced by the proximal renal tubule and Henle’s loop. It usually inhibits the nucleation, crystal growth, and aggregation phases of stone formation. However, nephrocalcin isolated from some stone formers has defective structure and function and …
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. …
What are the chemical precursors of renal stones? Relatively high concentrations of salt and acid solutes determine crystalluria and stone formation. Calcium oxalate is most common and is supersaturated to four to five times its solubility in normal urine. Other precursors are calcium phosphate (hydroxyapatite) and calcium phosphate monohydrate (brushite). Uric acid, cystine, struvite (magnesium …
What pathophysiologic factors influence the formation of renal stones? Renal stones result from hereditary or acquired disorders causing supersaturation of stone precursors, deficiency of stone inhibitors, and possibly excess promoters. Supersaturation causes crystallization with mineral precursors, such as calcium and oxalate. Calcium oxalate crystals bind to anionic sialic acid–containing glycoproteins on the apical surfaces of …
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What is the process of renal stone formation? Renal stone formation occurs in six steps: (1) Initially, urinary crystallization or precipitation of sparingly soluble salts and acids occurs. (2) Nucleation follows as crystals and urinary matrix ions form a stable framework for crystal enlargement through (3) growth and (4) aggregation. After the crystals sufficiently enlarge …
What conditions are associated with both renal stone disease and hypercalciuria? Calcium stones account for 80% of all kidney stones. Approximately 40% to 50% of calcium stone formers have hypercalciuria. Of those with hypercalciuria, 40% have IH, 5% have primary hyperparathyroidism, and 3% have renal tubular acidosis. Other causes of hypercalciuria include excessive dietary vitamin …
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