Hydroxyproline Influence on Oxalate Metabolism

Primary hyperoxaluria is an inborn error of metabolism that results in marked overproduction of oxalate by the liver. The excess oxalate causes kidney failure and can cause severe systemic disease due to oxalate deposition in multiple body tissues. Metabolic pathways that lead to oxalate are poorly understood, but recent evidence suggests that hydroxyproline may play a role. Sources of hydroxyproline include the diet and bone turnover. If hydroxyproline can be confirmed as a significant factor in primary hyperoxaluria, diet modification might be of value in reducing the severity of disease. This protocol, in which hydroxyproline labelled with a cold isotope is infused intravenously in patients with primary hyperoxaluria, will allow the researchers to measure the amount of oxalate produced from hydroxyproline. The contribution of hydroxyproline metabolism to the amount of oxalate excreted in urine in will be able to be determined for patients with each of the known types of primary hyperoxaluria.