title: Evaluation of intestinal phosphate binding to improve the safety profile of oral sodium phosphate bowel cleansing.
abstract: Prior to colonoscopy, bowel cleansing is performed for which frequently oral sodium phosphate (OSP) is used. OSP results in significant hyperphosphatemia and cases of acute kidney injury (AKI) referred to as acute phosphate nephropathy (APN; characterized by nephrocalcinosis) are reported after OSP use, which led to a US-FDA warning. To improve the safety profile of OSP, it was evaluated whether the side-effects of OSP could be prevented with intestinal phosphate binders. Hereto a Wistar rat model of APN was developed. OSP administration (2 times 1.2 g phosphate by gavage) with a 12h time interval induced bowel cleansing (severe diarrhea) and significant hyperphosphatemia (21.79 ± 5.07 mg/dl 6h after the second OSP dose versus 8.44 ± 0.97 mg/dl at baseline). Concomitantly, serum PTH levels increased fivefold and FGF-23 levels showed a threefold increase, while serum calcium levels significantly decreased from 11.29 ± 0.53 mg/dl at baseline to 8.68 ± 0.79 mg/dl after OSP. OSP administration induced weaker NaPi-2a staining along the apical proximal tubular membrane. APN was induced: serum creatinine increased (1.5 times baseline) and nephrocalcinosis developed (increased renal calcium and phosphate content and calcium phosphate deposits on Von Kossa stained kidney sections). Intestinal phosphate binding (lanthanum carbonate or aluminum hydroxide) was not able to attenuate the OSP induced side-effects. In conclusion, a clinically relevant rat model of APN was developed. Animals showed increased serum phosphate levels similar to those reported in humans and developed APN. No evidence was found for an improved safety profile of OSP by using intestinal phosphate binders.
authors: Laboratory of Pathophysiology, University of Antwerp, Antwerp, Belgium.
authors: Stef
authors: S
authors: Robijn
authors: Laboratory of Pathophysiology, University of Antwerp, Antwerp, Belgium.
authors: Benjamin A
authors: BA
authors: Vervaet
authors: Laboratory of Pathophysiology, University of Antwerp, Antwerp, Belgium.
authors: Patrick C
authors: PC
authors: D'Haese
authors: Laboratory of Pathophysiology, University of Antwerp, Antwerp, Belgium.
authors: Anja
authors: A
authors: Verhulst
mesh_terms: D058186:Acute Kidney Injury / Q000139:chemically induced*; D000284:Administration, Oral; D000536:Aluminum Hydroxide / Q000008:administration & dosage; D000818:Animals; D003113:Colonoscopy; D004195:Disease Models, Animal; D000089703:Fibroblast Growth Factor-23; D054559:Hyperphosphatemia / Q000139:chemically induced*; D007677:Kidney Function Tests; D007811:Lanthanum / Q000008:administration & dosage; D008297:Male; D010710:Phosphates / Q000008:administration & dosage / Q000009:adverse effects*; D051381:Rats; D017208:Rats, Wistar
chemical_list: C000717427:FGF23 protein, human; D010710:Phosphates; C119467:lanthanum carbonate; D000536:Aluminum Hydroxide; D007811:Lanthanum; D000089703:Fibroblast Growth Factor-23; C018279:sodium phosphate