P0096RENAL EXPRESSION AND CIRCULATING LEVELS OF CANONICAL WNT PATHWAY INHIBITORS IN THE EXPERIMENTAL MODEL OF EARLY CHRONIC KIDNEY DISEASE

Abstract

Abstract Background and Aims Molecular mechanisms implicated in the initial stages of inorganic phosphate (Pi) imbalance in chronic kidney disease (CKD) remain poorly understood. The aim of the study was to evaluate whether canonical Wnt pathway inhibitors (iWnt) involved in early response to Pi retention in CKD. Method Mild CKD was induced by 3/4 nephrectomy (NE, n=10) in spontaneously hypertensive rats (SHR) fed rat chow diet containing 0.8 % phosphate. Controls were sham operated SHR (SO, n=9). Duration of experimental exposure (NE or SO) was 4 months. Creatinine (Cr), albumin/ creatinine ratio (Alb/Cr), inorganic phosphate (Pi), fractional (FEPi) and daily Pi excretion (uPi24), intact parathyroid hormone (PTH), fibroblast growth factor 23 (FGF23), Klotho protein, sclerostin (SOST) and Dickkopf-1 (DKK1), SOST and DKK1 mRNA expression in kidney, renal interstitial fibrosis (RF) were analyzed. Results Levels of Alb/Cr, serum Cr, RF and indices of Pi exchange in the experimental model corresponded to mild CKD with Pi retention (Table). No differences were observed in serum levels of Klotho, FGF23 and PTH in experimental group vs controls (Table). Serum SOST and DKK1 concentrations were significantly higher in NE group while the kidney expression of SOST and DKK1 mRNAs decreased compared to SO (Table). Conclusion Early stages of experimental CKD are characterized by increased serum concentrations of sclerostin and Dickkopf-1 in the absence of Klotho, FGF23 or PTH levels alterations. The increase of circulating iWnt levels seems not to be associated with their renal biosynthesis and likely have a bone origin.