PB0050 - FGF23 Mediates Cardio-Renal Interaction in Asymptomatic Subjects With Chronic Elevation of Serum High-sensitivity Troponin: Implications for Multisystem Cardio-renal Risk

Background: Chronic troponin elevation is implicated in subclinical athero-thrombosis. Residual renal function is a marker of early atherosclerosis. We previously reported that serum levels of fibroblast growth factor 23 (FGF23), central factor in chronic kidney disease, are associated with left ventricular hypertrophy and increase in myocardial troponin I (TnI) and T (TnT) levels.

Aims: We aimed to evaluate the relationships among FGF23, TnI and TnT in asymptomatic healthy subjects.

Methods: Subjects taking regular physical checkup (n=297), who exhibited all test clinical items in reference range, were studied for systolic blood pressure (SBP), serum high-sensitivity TnI (hs-TnI, CLIA), TnT (hs-TnT, ECLIA), fasting blood sugar (FBS), HDL cholesterol (HDL-C), creatinine (CRE), alanine aminotransferase (ALT) and FGF23 (ELISA). Spearman’s correlation coefficient was calculated. Multiple linear regression analysis (stepwise way) was performed with TnI and TnT as dependent variables. SBP, FBS, HDL-C, CRE, ALT and FGF23 were independent variables.

Results: Hs-TnI levels (range 1.9-81.9 pg/mL) were higher than the 99-percentile of the general population (26.2) in 5 subjects. Hs-TnT levels (range 3.0-30.9) were higher than the 99-percentile of the general population (14.0) in 24 subjects. FGF23 levels (range < 3.0-613.3 pg/mL) were higher than the 99-percentile of the general population (10.0-74.8) in 11 subjects. Age correlated closely with hs-TnI (correlation coefficient r=0.383）and hs-TnT (r=0.687). Multiple linear regression analysis revealed that with hs-TnI as dependent variables, FBS (standard partial regression coefficient ß=0.1339) remained significant determinant. With hs-TnT as dependent variable, SBP (ß=0.242), FGF23 (ß=0.196) and FBS (ß=0.169) remained significant determinant. Hs-TnT remained as determinant of FGF23 after adjusting for CRE.

Conclusion(s): Even in healthy subjects circulating FGF23 levels are associated with modest hs-TnT increase in high normal reference range. A multisystem cardio-renal risk factors should be evaluated in healthy subjects with modest hs-TnT elevation, and FGF23 and hs-TnT can be used as biomarkers in subclinical athero-thrombosis with increased cardio-renal risk.