SP277
FGF-23, SKLOTHO AND SCLEROSTIN IN ASPECT OF VASCULAR CALCIFICATION IN RUSSIAN CHRONIC KIDNEY DISEASE PATIENTS

INTRODUCTION AND AIMS: Cardiovascular calcification (CVC) is a major contributor to the high incidence of cardiovascular events (CVE) in chronic kidney disease (CKD). Early CVC markers are actively sought now in CKD for cardio-renoprotective strategy optimization. Few studies examined novel CKD specific factors in parallel. No data are available from Russian CKD patients. We have conducted a cross-sectional study of FGF-23 (sFGF-23), Klotho (sKlotho) and sclerostin (sScl) serum levels along with traditional CKD-related factors such as serum phosphate (sP) and parathyroid hormone (PTH) and some general factors such as blood pressure, and examined their independent association with CVC in CKD patients.

METHODS: 131 CKD stage 1-5D patients were examined. In addition to routine laboratory tests, sFGF-23 (human FGF-23 ELISA (Merck Millipore) kit using monoclonal antibodies to the native human FGF-23 molecule), sKlotho (human soluble alfa-Klotho Assay (IBL-Takara), sScl (human ELISA kit , Biomedica) were measured. Pulse wave velocity (PWV) and central (aortic) blood pressure (by «Sphygmocor», Australia), cardiac (valvular) calcification score (by Echocardiography, semiquantitative scale), and aortic calcinosis score (by abdominal aorta radiography in lateral projection - Kauppila method) were performed.

RESULTS: In univariate analysis, all the factors of interest (sFGF-23, sKlotho, sScl) and also traditional CKD-related factors (sP, PTH and eGFR itself) as well as general factors (CSBP) were associated with PWV, aortic and valvular calcification. After multivariate analysis, including eGFR, was performed, sKlotho, sFGF-23, sP and CSBP results remained unchanged. The effects of sScl were lost except for the PWV, and the effects of eGFR were lost except for the presence of vascular calcification. PTH was associated only with valvular calcification. After subdividing the cohort by eGFR above or below 45 ml/min/1.73m2 the factors most associated with CVC in the former were: CSBP and sKlotho, while in the latter subgroup these main factors were: CSBP, sKlotho, FGF-23 and sP.

CONCLUSIONS: In early CKD stages (eGFR> 45 ml/min/1.73m2), the main independent factors associated with CVC were not only the same for general population such as CSBP, but also sKlotho, while for the subgroup with eGFR<45 ml/min/1.73m2, these main CVC factors were: CSBP, sKlotho, FGF-23 and sP.