Aldosterone and Mineralocorticoid Receptor Signaling as Determinants of Cardiovascular and Renal Injury: From Hans Selye to the Present

Background: A full understanding of the mechanisms of action of aldosterone and its interaction with the mineralocorticoid receptor (MR) allows a theoretical framework to predict the therapeutic potential of MR antagonists (MRAs) in CKD, and heart failure with reduced ejection fraction. Summary: The initial focus on the mechanisms of action of aldosterone was directed primarily on its role in modulating renal excretory function. In contrast, many recent studies have demonstrated a wider and expanded role for aldosterone in modulating inflammation, collagen formation, fibrosis, and necrosis. Increasing evidence has accrued that implicates the pathophysiological overactivation of the MR as a major determinant of progression of CKD. By promoting inflammation and fibrosis, MR overactivation constitutes a pivotal determinant of CKD progression and its associated morbidity and mortality. In accord with this mechanism of action, blockade of the MR is currently being investigated as a novel treatment regimen to slow the progression of CKD. The recently reported FIDELIO-DKD (FInerenone in reducing kiDnEy faiLure and dIsease prOgression in Diabetic Kidney Disease) study demonstrated that patients with CKD and type 2 diabetes who were treated with finerenone (a novel nonsteroidal MRA) manifested a lower risk of a composite primary outcome event compared with patients in the placebo arm (defined as kidney failure, or a sustained decrease of ≥40% in the estimated glomerular filtration rate from baseline, or death from renal causes). In addition, patients in the finerenone group also manifested a lower risk of a key secondary outcome event (defined as death from cardiovascular causes, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for heart failure). Key Messages: Based on the success of the FIDELIO-DKD study, future studies should be implemented testing the hypothesis that a wide array of nondiabetic CKD is modulated by overactivation of the MR, and consequently may be amenable to treatment with novel nonsteroidal MRAs. Future studies are encouraged to elucidate the clinical implications of the interplay of nonsteroidal MRAs and the components of the renin-angiotensin cascade. The unique and recently reported interrelationship of fibroblast growth factor (FGF23) and aldosterone may also constitute a propitious subject for future investigation.