Background: Nicotinamide phosphoribosyltransferase (Nampt) is an enzyme involved in nicotinamide adenine dinucleotide biosynthesis. Nampt functions as gatekeeper of energy status and survival in cardiac myocytes in animal models of ischemia-reperfusion and might regulate inflammatory processes. Therefore, we performed for the 1st time a clinical study to determine the effects of Nampt on cardiac function in patients with nonischemic dilated (DCM) and inflammatory (DCMi) cardiomyopathy.
Methods and results: A total of 113 patients were enrolled in the study and classified into control (n = 25), DCM (n = 38), and DCMi (n = 50) groups. Cardiac functional and inflammatory parameters as well as plasma Nampt and cardiac mRNA and protein Nampt expression were determined at baseline and follow-up after 6 months. Patients with DCM (1.04 ± 0.8 ng/mL; P < .001) and DCMi (1.07 ± 0.7 ng/mL; P < .001) showed significantly increased Nampt plasma concentrations at baseline compared with the control group (0.57 ± 0.5 ng/mL). Patients with higher Nampt concentrations in both heart failure groups showed significant better improvement of cardiac functional parameters (correlation between Nampt plasma levels and the change of left ventricular ejection fraction after 6 months: DCM: r = 0.698, P < .001; DCMi: r = 0.503, P < .001). Moreover, cardiac inflammation did not influence Nampt expression, and Nampt concentrations did not modulate cardiac inflammation in DCMi. A multivariate linear regression model revealed high plasma Nampt expression to contribute to better improvement of cardiac function in patients of both heart failure groups. Moreover, heart failure patients with high plasma Nampt levels showed suppressed cardiac TNF-α and IL-6 mRNA expression after 6 months' follow-up as well as lower B-type natriuretic peptide levels compared with heart failure patients with low Nampt plasma concentrations.
Conclusions: High Nampt expression in patients with nonischemic DCM and DCMi is associated with a favorable outcome and improvement in functional status.
Keywords: Nampt; cardiomyopathy; heart failure.
Copyright © 2015 Elsevier Inc. All rights reserved.