Linkage of Fibroblast Growth Factor 23 and Phosphate in Serum: Phosphate and Fibroblast Growth Factor 23 Reduction by Increasing Dose of Sevelamer.

Background: High serum phosphate and fibroblast growth factor-23 (FGF-23) levels are well-recognized independent risk factors of mortality and morbidity in patients with chronic kidney diseases (CKDs). Sevelamer, as a phosphate chelating agent, reduces serum phosphate and FGF-23 levels produced by bone osteocytes. This study aimed to determine the best dose at which sevelamer could successfully reduce serum phosphate and FGF-23 levels in rat models of adenine-induced CKD.

Methods: CKD was induced using adenine. Healthy and CKD-induced rats were divided into 6 groups as follows: healthy controls; CKD controls; rats treated with 1%, 2%, and 3% sevelamer for CKDs; and healthy rats administered 3% sevelamer. Biochemical factors and serum FGF-23 levels were measured using spectrophotometry and enzyme-linked immunosorbent assay methods.

Results: Serum phosphate levels were best decreased in rats receiving 3% sevelamer in their diet (5.91±1.48 mg/dL vs. 8.09±1.70 mg/dL, <0.05) compared with the CKD control rats. A dose-dependent decrease in serum FGF-23 levels was observed, and the most significant results were obtained in rats receiving 3% sevelamer compared with the CKD control rats (142.60±83.95 pg/mL vs. 297.15±131.10 pg/mL, <0.01).

Conclusions: Higher sevelamer doses significantly reduced serum phosphate and FGF-23 levels in adenine-induced CKD rats.