Inflammation of the calcified aortic valve in cardiac patients is associated with activation of the local aldosterone system, promoting oxidative stress–driven pathological responses
S Hmadeh, R B Basso, A M Mroueh, A T Trimaille, H M Muzammel, M M Mortada, T A M Mai, T M H Hoang, M P P Pieper, M K Kindo, O M Morel, V S K Schini-KerthAbstract
Introduction
Low-grade inflammation is a major contributor to the development and progression of calcified aortic stenosis (AS). Inflammatory activity within calcified valves is heterogeneous, with high-grade inflammation involving activation of the AT1R/NADPH oxidase/SGLT1/2 axis that drives pro-inflammatory, pro-calcific, pro-remodeling, and fibrotic responses. Although angiotensin and aldosterone pathways are closely interconnected, the role of aldosterone synthase (AS) in mediating inflammatory and oxidative processes within human calcified aortic valves remains insufficiently understood.
Aim
To evaluate aldosterone-mediated pro-oxidant responses in the calcified aortic valve and in peripheral blood mononuclear cells (PBMCs) of patients with aortic stenosis.
Methods
Pathological aortic valves and PBMCs were collected from patients undergoing surgical aortic valve replacement at the University Hospital of Strasbourg. Protein expression was assessed by Western blot, and in situ localization within valve tissue was examined by immunofluorescence staining. ROS production was measured using dihydroethidium (DHE) staining. In PBMCs, glucose uptake was quantified using 2-NBDG, and aldosterone release by ELISA.
Results
ROS levels were increased 1.7-fold in calcified aortic valve regions compared with non-calcified areas, and this augmented oxidative activity was significantly attenuated by NAC, losartan, VAS-2870, empagliflozin, eplerenone, and FAD286. Exogenous aldosterone markedly enhanced ROS production in non-calcified valves, an effect fully reversed by the same inhibitors, whereas calcified valves were unresponsive to aldosterone stimulation. Calcified valves demonstrated a pronounced upregulation of aldosterone synthase (AS), with immunofluorescence analyses localizing AS predominantly to CD68-positive macrophages. PBMCs from aortic stenosis patients exhibited elevated ROS generation and increased glucose uptake, both of which were significantly reduced by NAC, losartan, VAS-2870, empagliflozin, eplerenone, and FAD286. Combined inhibition with FAD286 (1 nM) and empagliflozin (10 nM) produced a synergistic suppression of ROS and glucose uptake, as confirmed by synergy analysis. AS expression in PBMCs from aortic stenosis patients was higher than in healthy controls, and was downregulated by VAS-2870, empagliflozin, and FAD286, and slightly by losartan. ELISA quantification showed aldosterone release was elevated in PBMCs from aortic stenosis patients relative to healthy subjects, markedly reduced by FAD286 whereas empagliflozin and eplerenone had minor effects.
Conclusion
Aldosterone synthase is upregulated in calcified aortic valves, particularly within infiltrating macrophages, and promotes pro-oxidant and metabolic dysregulation in both valve tissue and PBMCs. These findings suggest that aldosterone signaling contributes to the progression of calcified aortic stenosis and represents a potential therapeutic target.