Topography, Composition and Structure of Incipient Randall Plaque at the Nanoscale Level

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• 作者：Cé ; cile Verrier^b ; ^c ; Dominique Bazin^d ; ^h ; Lé ; a Huguet^b ; Odile Sté ; phan^h ; Alexandre Gloter^h ; Marie-Christine Verpont^b ; Vincent Frochot^e ; Jean-Philippe Haymann^b ; ^e ; Isabelle Brocheriou^b ; ^f ; Olivier Traxer^a ; ^g ; Michel Daudon^b ; ^e ; Emmanuel Letavernier^b ; ^e ; ^{emmanuel.letavernier@tnn.aphp.fr" class="auth_mail" title="E-mail the corresponding author}
• 关键词：kidney medulla ; nephrolithiasis ; calcium phosphate ; nanoparticles ; calcinosis
• 刊名：The Journal of Urology
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：196
• 期：5
• 页码：1566-1574
• 全文大小：4464 K

文摘

Randall identified calcium phosphate plaques in renal papillae as the origin of kidney stones. However, little is known about the early steps of Randall plaque formation preceding the onset of urolithiasis. Our objective was to characterize the composition and the initial formation site of incipient Randall plaque in nonstone forming, living patients.

Materials and Methods

Median patient age was 67.7 years. A total of 54 healthy papillae from kidneys removed for cancer and without stones were analyzed by immunohistochemistry and von Kossa staining, field emission-scanning electron microscopy with energy dispersive x-ray analysis, μ-Fourier transform infrared spectroscopy, cryo-transmission electron microscopy coupled to selected area electron diffraction and electron energy loss spectroscopy.

Results

Incipient Randall plaque was observed in 72.7% of kidneys. As expected, carbonated apatite was the main component of microcalcifications but amorphous calcium phosphate and whitlockite were identified in 80% and 40% of papillae, respectively. Incipient plaques were noted in the deepest part of the papillae around the loop of Henle tip as well as around the vasa recta, representing 62.4% and 37.2% of microcalcifications, respectively. Plaques were rarely close to collecting ducts. At the nanoscale level incipient calcifications were often composed of several nanocrystals in organic material that looked like microvesicles.

Conclusions

Incipient Randall plaque is frequent. It appears not only at the extreme tip of the renal papillae around the hairpin structure of the loop of Henle but also around the vasa recta. Nanoscale analyses suggest a local nucleation process promoting nanocrystal growth in a supersaturated milieu. In addition, plaques contain various calcium and magnesium phosphates, and not only carbonated apatite.