Abstract 5898: The Reduction of Myocardial Apelin Production in Humans with Systolic Left Ventricular Dysfunction
Apelin is a novel endogenous inotropic, vasodilating peptide that is the ligand for the APJ receptor. Apelin and APJ are widely distributed in the endothelium of number of organs including the heart. Apelin concentrations are reduced in individuals with left ventricular systolic dysfunction (LVSD) and increased in ventricles which remodel favourably following LVADs. However it is not known whether apelin is produced in the heart. We measured the plasma apelin and BNP concentrations in the coronary sinus (CS), aorta (Ao) and renal vein (RV) of 21 individuals with heart failure undergoing right & left heart catheterisation or CRT implantation and compared it with samples from 10 controls that did not have structural heart disease attending for elective EP investigation. In all individuals comparison of paired samples demonstrated a reduction of log BNP from CS to Ao to RV. The log apelin concentration was higher in the CS than Ao however there was no difference between apelin in Ao and RV (Figure 1⇓). In patients with LVSD there was a significant reduction in log CS apelin compared to controls (5.78 +/−0.05 vs 6.08 +/−0.1, p<0.005) but log Ao apelin (5.79 +/− 0.04 vs 5.73 +/− 0.11, p=0.99) and log RV apelin (5.79 +/− 0.14 vs 5.96 +/− 0.13, p=0.41) were no different. BNP was increased in the CS (6.38 +/− 0.21 vs 4.34 +/− 0.26), Ao (5.73 +/− 0.22 vs 3.86 +/−0.31) and RV (5.56 +/− 0.35 vs 3.53+/− 0.27) compared to controls, p<0.0001. For the first time it has been shown that apelin is produced in the heart and that myocardial apelin production is reduced in individuals with LVSD. However, unlike BNP, apelin production is not restricted to the heart in humans.