Endothelial epoxyeicosatrienoic acid release is intact in aldosterone excess

Endothelial dysfunction (ED) is considered to be a major driver of the increased incidence of cardiovascular disease in primary aldosteronism (PA). The functionality of the epoxyeicosatrienoic acid (EET) pathway, involving the release of beneficial endothelium-derived lipid mediators, in PA is unknown. Evidence suggests this pathway to be disturbed in various models of experimental hypertension. We therefore assessed EET production in primary human coronary artery endothelial cells exposed to aldosterone excess and measured circulating EET in patients with PA.

We used qPCR to investigate changes in the expression levels of essential genes for the synthesis and degradation of EET, calcium imaging to address the functional impact on overall endothelial function, as well as mass spectrometry to determine endothelial synthetic capacity to release EET upon stimulation. RNA-seq was performed to gain further mechanistic insights. Eicosanoid concentrations in patient's plasma were also determined by mass spectrometry.

Aldosterone, while eliciting proinflammatory VCAM1 expression and disturbed calcium response to acetylcholine, did not negatively affect stimulated release of endothelial EET. Likewise, no differences were observed in eicosanoid concentrations in plasma from patients with PA when compared to essential hypertensive controls. However, an inhibitor of soluble epoxide hydrolase abrogated aldosterone-mediated VCAM1 induction and led to a normalized endothelial calcium response probably by restoring expression of CHRNE.

EET release appears intact despite aldosterone excess. Epoxide hydrolase inhibition may revert aldosterone-induced functional changes in endothelial cells. These findings indicate a potential new therapeutic principle to address ED, which should be explored in future preclinical and clinical trials.