Fibroblast growth factor-23 (FGF-23) / soluble Klotho protein (sKlotho) / sclerostin glycoprotein ratio disturbance is a novel risk factor for cardiovascular complications in ESRD patients receiving treatment with regular hemodialysis or hemodiafiltration

Aim: Aim of the study was to explore the role of the FGF-23/sKlotho/sclerostin ratio disturbance in the determining of cardiovascular risk in end stage renal disease (ESRD) patients, receiving treatment with regular hemodialysis (НD) or hemodiafiltration (НDF) online in Russia.

Materials and methods: 42 patients with ESRD, at the age of 18-55 years, treated with HD or HDF on line for at least 6 months, were examined. 22 (52.3%) patients received traditional HD, the remaining 20 (47.7%) - HDF online. In all the patients, in addition to a general examination, the serum levels of FGF-23, sKlotho, sclerostine (by ELISA), their associations with cardiovascular risk factors (left ventricular hypertrophy (LVH), acute coronary syndrome (ACS), serum troponin I levels) with the numbers of techniques (ECG; Eho-CGF (with calculation of left ventricular myocardium mass index (LVMMI), as well as the relative thickness of the walls of the left ventricle (RWT); sphygmography (central (aortal) blood pressure (CBP), subendocardial blood flow (SBF) - by «Sphygmocor»), and the effect of regular HD and HDF on serum levels of the studied markers, were assessed.

Results: An independent effect of FGF-23 on the risk of LVH, as well as on the increase of serum troponin I in the studied ESRD patients [β=3.576 p<0.01, and β=1.115, p<0.05, respectively] was found. Serum Klotho was the factor most associated with the CBP [β=-0.023; p<0.001]. The increased serum sclerostin was correlated with a lower incidence of both reduced SBF [r=0.492; p<0.05], symptoms of coronary heart disease [r=-0.449; p<0.05] and rhythm disturbances [r=-0.446; p<0.05]. In addition, in HD patients higher FGF-23 and lower Klotho and sclerostine serum levels were associated with: inadequate dialysis syndrome (Kt/V <1.1; r=0.463; p<0.05), chronic inflammation (C-reactive protein >10 mg/L; r=0.612; p<0.01), and with a decrease in serum albumin level (<35 g/l; r=0.459; p<0.05). The FGF-23/sKlotho/sclerostin ratio disturbance was more pronounced in patients treated with traditional HD then HDF online. A direct correlation (r=0.445; p<0.05) was established between FGF-23 serum levels and serum phosphorus, which was more pronounced in HD patients (r=0.545; p<0.01).

Conclusion: In HD and HDF ESRD patients, higher serum FGF-23 and lower sKlotho and sclerostin levels were associated with a chronic inflammation, malnutrition, secondary hyperparathyroidism, and may considered as predictors of cardiovascular complications such as LVH, ACS, rhythm disturbances, persisting of subincreased serum troponin I.