Kidney Stones Research Today is a free monthly online journal that collates and summarizes the latest research about Kidney Stones, including details on causes, symptoms, treatment, diagnosis of nephrolithiasis, calculi.

Mechanism of formation of human calcium oxalate renal stones on Randall's plaque.

Evan AP, Coe FL, Lingeman JE, Shao Y, Sommer AJ, Bledsoe SB, Anderson JC, Worcester EM

Department of Anatomy and Cell Biology, Indiana University, School of Medicine, Indianapolis, Indiana 46223, USA. evan@anatomy.iupui.edu

Although calcium oxalate (CaOx) renal stones are known to grow attached to renal papillae, and specifically to regions of papillae that contain Randall's plaque (interstitial apatite deposits), the mechanisms of stone overgrowth on plaque are not known. To investigate the problem, we have obtained biopsy specimens from two stone patients that included an attached stone along with its tissue base and have studied the ultrastructural features of the attachment point using light and transmission electron microscopy, Fourier transform infrared spectroscopy (mu-FTIR), and immunohistochemical analysis. The epithelium is disrupted at the attachment site. The denuded plaque that borders on the urinary space attracts an envelope of ribbon-like laminates of crystal and organic matrix arising from urine ions and molecules. Into the matrix of this ribbon grow amorphous apatite crystals that merge with and give way to the usual small apatite crystals imbedded in stone matrix; eventually CaOx crystals admix with apatite and become the predominant solid phase. Over time, urine calcium and oxalate ions gradually overgrow on the large crystals forming the attached stone.

Published 17 September 2007 in Anat Rec (Hoboken), 290(10): 1315-23.
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