Background: Elabela (ELA) is a recently identified apelin receptor agonist essential for cardiac
development, but its biology and therapeutic potential are unclear. In humans, ELA transcripts are
detected in embryonic stem cells, induced pluripotent stem cells, kidney, heart and blood vessels. ELA
through the apelin (APJ) receptor promotes angiogenesis in vitro, relaxes murine aortic blood vessels
and attenuates high blood pressure in vivo. The APJ receptor when bound to its original ligand, apelin,
exerts peripheral vasodilatory and positive inotropic effects, conferring cardioprotection in vivo.
Methods: This study initially assessed endogenous ELA expression in normal and diseased rats and
then characterized the effects of long-term ELA gene delivery by adeno-associated virus serotype 9
(AAV9) vectors on cardiorenal function in Dahl salt-sensitive rats (DS) on a high-salt diet over 3
Results: Endogenous ELA was predominantly expressed in the kidneys, especially in the renal collecting
duct cells and was not affected by disease. Rat ELA was overexpressed in the heart via AAV9 vector
by a single intravenous injection. ELA-treated animals showed delayed onset of blood pressure elevation.
Prior to high-salt diet, a reduction in the fractional sodium and chloride excretion was observed
in rats given the AAV9-ELA vector. After three months on a high-salt diet, ELA preserved glomerular
architecture, decreased renal fibrosis and suppressed expression of fibrosis-associated genes in the kidneys.
Conclusion: ELA is constitutively expressed in renal collecting ducts in rats. Sustained AAV-ELA expression
may offer a potential long-term therapy for hypertension and renal remodeling.