Table of Contents
Advances in Nephrology
Volume 2014, Article ID 538392, 10 pages
http://dx.doi.org/10.1155/2014/538392
Research Article

Calcium Carbonate versus Sevelamer Hydrochloride as Phosphate Binders after Long-Term Disease Progression in 5/6 Nephrectomized Rats

1School of Medicine, University of Tampere, 33014 Tampere, Finland
2Department of Ophthalmology, Tampere University Hospital, P.O. Box 2000, 33521 Tampere, Finland
3Department of Clinical Chemistry, Etelä-Pohjanmaa Central Hospital Laboratory, 60220 Seinäjoki, Finland
4Department of Pharmacology and Toxicology, Biocenter Oulu, University of Oulu, P.O. Box 5000, 99014 Oulu, Finland
5Department of Internal Medicine, Tampere University Hospital, P.O. Box 2000, 33521 Tampere, Finland

Received 17 May 2014; Revised 2 July 2014; Accepted 5 August 2014; Published 24 August 2014

Academic Editor: Carlos G. Musso

Copyright © 2014 Suvi Törmänen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Our aim was to compare the effects of calcium carbonate and sevelamer-HCl treatments on calcium-phosphate metabolism and renal function in 5/6 nephrectomized (NX) rats so that long-term disease progression preceded the treatment. After 15-week progression, calcium carbonate (3.0%), sevelamer-HCl (3.0%), or control diets (0.3% calcium) were given for 9 weeks. Subtotal nephrectomy reduced creatinine clearance (−40%), plasma calcidiol (−25%), and calcitriol (−70%) and increased phosphate (+37%), parathyroid hormone (PTH) (11-fold), and fibroblast growth factor-23 (FGF-23) (4-fold). In NX rats, calcium carbonate diet increased plasma (+20%) and urinary calcium (6-fold), reduced plasma phosphate (−50%) and calcidiol (−30%), decreased creatinine clearance (−35%) and FGF 23 (−85%), and suppressed PTH without influencing blood pH. In NX rats, sevelamer-HCl increased urinary calcium (4-fold) and decreased creatinine clearance (−45%), PTH (−75%), blood pH (by 0.20 units), plasma calcidiol (−40%), and calcitriol (−65%). Plasma phosphate and FGF-23 were unchanged. In conclusion, when initiated after long-term progression of experimental renal insufficiency, calcium carbonate diet reduced plasma phosphate and FGF-23 while sevelamer-HCl did not. The former induced hypercalcemia, the latter induced acidosis, while both treatments reduced vitamin D metabolites and deteriorated renal function. Thus, delayed initiation influences the effects of these phosphate binders in remnant kidney rats.