Article Text

Download PDFPDF
Translational promise of the apelin–APJ system
  1. Gareth Barnes1,
  2. Alan G Japp2,
  3. David E Newby1,2
  1. 1Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
  2. 2Edinburgh Heart Centre, Royal Infirmary of Edinburgh, Edinburgh, UK
  1. Correspondence to Dr Gareth Barnes, Rm SU305 The Chancellors Building, 49 Little France Crescent, University of Edinburgh, Edinburgh EH16 4SA, UK; gareth.barnes{at}


Apelin, the endogenous ligand for the G-protein-coupled APJ receptor, is emerging as a key hormone in cardiovascular homoeostasis. It is expressed in a diverse range of tissues with particular preponderance for the cardiovascular system, being found in both the heart and vasculature. Apelin is the most potent in vitro inotrope yet identified and causes endothelium- and nitric oxide-dependent vasodilatation. It also appears to have a role in lipid and glucose metabolism as well as fluid homoeostasis. One of the key emerging features of the apelin–APJ system is its interaction with the renin–angiotensin system with the respective receptors sharing marked sequence homology, forming heterodimers, and mediating opposing physiological actions.

To date, both preclinical and limited clinical studies suggest that the apelin–APJ system may have an important role in the pathogenesis of heart failure. Although the apelin–APJ system is downregulated, the inotropic actions of apelin persist and are enhanced in failing hearts without inducing ventricular hypertrophy. In combination with its interaction with the renin–angiotensin system, APJ agonism may provide a new therapeutic target in the treatment of acute and chronic heart failure.

In this review, we highlight key aspects of the apelin–APJ system in health and disease, and consider its translational and therapeutic potential. The diverse actions of the apelin–APJ system have implications for understanding the pathophysiology of, and development of treatments for, several major cardiovascular diseases.

  • Renin-angiotensin system
  • endothelium

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.


  • Funding British Heart Foundation Clinical PhD Training Fellowships to GB (FS/09/019) and AGJ (FS/06/064).

  • Competing interest None.

  • Provenance and peer review Commissioned; externally peer reviewed.