ABSTRACT
According to our current view of calcium oxylate (CaOx) stone formation, subepithelial deposits (plaques) and intratubular plugs of CaP (HAP) are considered to be of great importance. It also is obvious that without a sufficient renal supply of phosphate, no intratubular or interstitial CaP precipitates will form. Despite these conclusions, we need a more complete understanding of how and where the initial CaP precipitation takes place. Such information is necessary to elucidate the exact role of phosphate in patients with calcium oxalate stone disease. Irrespective of our shortcomings so far, there is sufficient evidence that phosphate needs appropriate attention.
In this chapter some mechanisms that might underlie the development of CaP solid phases and their role in subsequent crystallization of CaOx are discussed briefly. Dietary phosphate thus apparently has stone-promoting properties, but intestinal phosphate also forms complexes with calcium and reduces calcium absorption. Moreover, urinary pyrophosphate is a crystallization inhibitor.
Increased research efforts are highly desirable in order to better understand when, where, and how pathological precipitation of CaP occurs and how it possibly can be counteracted.
