Supplementary Material for: Interaction of Soluble CXC Ligand 16 and Cardiac Injury Markers in Hemodialysis Patients

Background: Recent data suggest that there is a pathogenic role for CXC ligand 16 (CXCL16) in cardiovascular diseases. Little is known about circulating CXCL16 in patients with kidney dysfunction. We explored the relationships of plasma CXCL16 with cardiac injury markers in a group of dialysis patients. Methods: Plasma CXCL16 and C-reactive protein (CRP) were measured in 366 patients who were on maintenance hemodialysis. Cardiac injury was evaluated via measurements of the circulating B-type natriuretic peptide (BNP), N-terminal prohormone of brain natriuretic peptide (NT proBNP), Troponin I (TnI), and Troponin T (TnT). Sixty healthy subjects who were frequency matched with the patients on the basis of age and gender were recruited as healthy controls. Results: The mean age of the patients was 52.5 ± 12.1 years and 56.3% were male. Circulating CXCL16 was significantly higher in the patients than in the controls (patients vs. controls: 477.3 (367.0-647.1) pg/mL vs. 229.5 (203.8-254.5) pg/mL; p < 0.001). The log-transformed (log-) CXCL16 level was correlated with all 4 cardiac markers (log-BNP, log-NTproBNP, log-TnI, and log-TnT) with high levels of significance (all p < 0.001), even after extensive controls for the covariates. In contrast, CRP was correlated only with BNP (marginally) and NT proBNP and was not correlated with troponins. Conclusion: We showed, for the first time, highly significant relationships of circulating CXCL16 level with cardiac injury markers in dialysis patients. Our data suggest that circulating CXCL16 is possibly involved in the pathological process of cardiovascular damage in dialysis patients and may serve as a therapeutic target for cardiac protection in these patients.