The epoxyeicosatrienoic pathway is intact in endothelial and smooth muscle cells exposed to aldosterone excess

Abstract

Objectives: Endothelial dysfunction (ED) is considered to be a major driver of the increased incidence of cardiovascular disease in primary aldosteronism (PA). Whether the epoxyeicosatrienoic acid (EET) pathway, involving the release of beneficial endothelium-derived lipid mediators, contributes to ED in PA is unknown. Preclinical evidence suggests this pathway to be relevant in the pathogenesis in various models of experimental hypertension. In addition, an orally available soluble epoxide hydrolase inhibitor, which halts the breakdown of EETs, has already passed a phase 1 clinical trial. We, therefore, exposed primary human coronary artery endothelial cells to 1 nM aldosterone. Methods: We used qPCR to investigate changes in the expression levels of essential genes for the synthesis and degradation of EETs as well as mass spectrometry to determine endothelial synthetic capacity to release EETs upon stimulation. We also assessed primary human coronary artery smooth muscle cells for expression of putative EET receptor ion channels or downstream mediators as well as for the calcium response to EETs using calcium imaging. Results: No major aldosterone-related expression changes were detected on the endothelial as well as the smooth muscle side. Stimulated release of endothelial EETs was unaffected. Likewise, the smooth muscle calcium response was unchanged after aldosterone excess. Conclusions: The EET pathway is not negatively affected by increased aldosterone concentrations as seen in PA. Modulating the EET pathway with therapeutic intent in patients with PA might therefore be assessed in future preclinical and clinical trials to address ED.