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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Effects of Dietary Phosphate on Adynamic Bone Disease in Rats with Chronic Kidney Disease - Role of Sclerostin?

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Author(s):
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Ferreira, Juliana C. [1] ; Ferrari, Guaraciaba O. [1] ; Neves, Katia R. [1] ; Cavallari, Raquel T. [1] ; Dominguez, Wagner V. [1] ; dos Reis, Luciene M. [1] ; Graciolli, Fabiana G. [1] ; Oliveira, Elizabeth C. [1] ; Liu, Shiguang [2] ; Sabbagh, Yves [2] ; Jorgetti, Vanda [1] ; Schiavi, Susan [2] ; Moyses, Rosa M. A. [1]
Total Authors: 13
Affiliation:
[1] Univ Sao Paulo, Div Nephrol, Dept Internal Med, Sao Paulo - Brazil
[2] Genzyme Corp, Sanofi Genzyme R&D Ctr, Framingham, MA - USA
Total Affiliations: 2
Document type: Journal article
Source: PLoS One; v. 8, n. 11 NOV 13 2013.
Web of Science Citations: 29
Abstract

High phosphate intake is known to aggravate renal osteodystrophy along various pathogenetic pathways. Recent studies have raised the possibility that dysregulation of the osteocyte Wnt/beta-catenin signaling pathway is also involved in chronic kidney disease (CKD)-related bone disease. We investigated the role of dietary phosphate and its possible interaction with this pathway in an experimental model of adynamic bone disease (ABD) in association with CKD and hypoparathyroidism. Partial nephrectomy (Nx) and total parathyroidectomy (PTx) were performed in male Wistar rats. Control rats with normal kidney and parathyroid function underwent sham operations. Rats were divided into three groups and underwent pair-feeding for 8 weeks with diets containing either 0.6% or 1.2% phosphate: sham 0.6%, Nx+PTx 0.6%, and Nx+ PTx 1.2%. In the two Nx+ PTx groups, serum creatinine increased and blood ionized calcium decreased compared with sham control group. They also presented hyperphosphatemia and reduced serum parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23) levels. Fractional urinary excretion of phosphate increased in Nx+ PTx 1.2% rats despite lower PTH and FGF23 levels than in sham group. These biochemical changes were accompanied by a decrease in bone formation rates. The Nx+ PTx 1.2% group had lower bone volume (BV/TV), higher osteoblast and osteocyte apoptosis, and higher SOST and Dickkopf-1 gene expression than the Nx +PTx 0.6% group. Nx+ PTx 0.6% rat had very low serum sclerostin levels, and Nx+ PTx 1.2% had intermediate sclerostin levels compared with sham group. Finally, there was a negative correlation between BV/TV and serum sclerostin. These results suggest that high dietary phosphate intake decreases bone volume in an experimental model of CKD-ABD, possibly via changes in SOST expression through a PTH-independent mechanism. These findings could have relevance for the clinical setting of CKD-ABD in patients who low turnover bone disease might be attenuated by optimal control of phosphate intake and/or absorption. (AU)