APLN and heart failure: Apelinergic gene expression levels are altered in conditions of hypertension, e.g., myocardium aplnr/apln levels are down-regulated in experimental heart failure in Dahl salt-sensitive rats (Iwanaga et al., 2006) and decreased aplnr/apln levels are seen in the heart and aorta of SHRs compared to normotensive rats (Zhong et al., 2005), while aplnr/apln levels and apelin/APJ protein are up-regulated in the PVN of SHR (Zhang et al., 2014), reflecting a differential peripheral vs. central expression pattern.