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This Article Full Text Full Text (PDF) All Versions of this Article: 294/5/F1109    most recent 00620.2007v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Khan, S. R. Articles by Glenton, P. A. Search for Related Content PubMed PubMed Citation Articles by Khan, S. R. Articles by Glenton, P. A.

Calcium oxalate crystal deposition in kidneys of hypercalciuric mice with disrupted type IIa sodium-phosphate cotransporter

Department of Pathology, Immunology, and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, Florida

Submitted 29 December 2007 ; accepted in final form 9 March 2008

The most common theories about the pathogenesis of idiopathic kidney stones consider precipitation of calcium phosphate (CaP) within the kidneys critical for the development of the disease. We decided to test the hypothesis that a CaP substrate can promote the deposition of calcium oxalate (CaOx) in the kidneys. Experimental hyperoxaluria was induced by feeding glyoxylate to male mice with knockout (KO) of NaP_i IIa (Npt2a), a sodium-phosphate cotransporter. Npt2a KO mice are hypercalciuric and produce CaP deposits in their renal tubules. Experimental hyperoxaluria led to CaOx crystalluria in both the hypercalciuric KO mice and the normocalciuric control B6 mice. Only the KO mice produced CaOx crystal deposits in their kidneys, but the CaOx crystals deposited separately from the CaP deposits. Perhaps CaP deposits were not available for a CaOx overgrowth. These results also validate earlier animal model observations that showed that CaP substrate is not required for renal deposition of CaOx and that other factors, such as local supersaturation, may be involved. The absence of CaOx deposition in the B6 mice despite extreme hyperoxaluria also signifies the importance of both calcium and oxalate in the development of CaOx nephrolithiasis.

hypercalciuria; hyperoxaluria; Randall's plaque; Npt2a knockout mice