Association Between Mineralocorticoid Receptor Antagonist Use and Outcome in Myocardial Infarction Patients With Heart Failure

The choroidal nervous system: a link between mineralocorticoid receptor and pachychoroid

Central serous chorioretinopathy (CSCR) belongs to the pachychoroid spectrum, a pathological phenotype of the choroidal vasculature, in which blood flow is under the choroidal nervous system (ChNS) regulation. The pathogenesis of CSCR is multifactorial, with the most recognised risk factor being intake of glucocorticoids, which activate both the gluco- and the mineralocorticoid (MR) receptors. As MR over-activation is pathogenic in the retina and choroid, it could mediate the pathogenic effects of glucocorticoids in CSCR. But the role of MR signalling in pachychoroid is unknown and whether it affects the ChNS has not been explored. Using anatomo-neurochemical characterisation of the ChNS in rodents and humans, we discovered that beside innervation of arteries, choroidal veins and choriocapillaris are also innervated, suggesting that the entire choroidal vasculature is under neural control. The numerous synapses together with calcitonin gene-related peptide (CGRP) vesicles juxtaposed to choroidal macrophages indicate a neuro-immune crosstalk. Using ultrastructural approaches, we show that transgenic mice overexpressing human MR, display a pachychoroid-like phenotype, with signs of choroidal neuropathy including myelin abnormalities, accumulation and enlargement of mitochondria and nerves vacuolization. Transcriptomic analysis of the RPE/choroid complex in the transgenic mice reveals regulation of corticoids target genes, known to intervene in nerve pathophysiology, such as Lcn2, rdas1/dexras1, S100a8 and S100a9, rabphilin 3a (Rph3a), secretogranin (Scg2) and Kinesin Family Member 5A (Kif5a). Genes belonging to pathways related to vasculature development, hypoxia, epithelial cell apoptosis, epithelial mesenchymal transition, and inflammation, support the pachychoroid phenotype and highlight downstream molecular targets. Hypotheses on the imaging phenotype of pachychoroid in humans are put forward in the light of these new data. Our results provide evidence that MR overactivation causes a choroidal neuropathy that could explain the pachychoroid phenotype found in transgenic mice overexpressing human MR. In patients with pachychoroid and CSCR in which systemic dysautonomia has been demonstrated, MR-induced choroidal neuropathy could be the missing link between corticoids and pachychoroid.

Cardiovascular Disease in Obstructive Sleep Apnea: Putative Contributions of Mineralocorticoid Receptors

Obstructive sleep apnea (OSA) is a chronic and highly prevalent condition that is associated with oxidative stress, inflammation, and fibrosis, leading to endothelial dysfunction, arterial stiffness, and vascular insulin resistance, resulting in increased cardiovascular disease and overall mortality rates. To date, OSA remains vastly underdiagnosed and undertreated, with conventional treatments yielding relatively discouraging results for improving cardiovascular outcomes in OSA patients. As such, a better mechanistic understanding of OSA-associated cardiovascular disease (CVD) and the development of novel adjuvant therapeutic targets are critically needed. It is well-established that inappropriate mineralocorticoid receptor (MR) activation in cardiovascular tissues plays a causal role in a multitude of CVD states. Clinical studies and experimental models of OSA lead to increased secretion of the MR ligand aldosterone and excessive MR activation. Furthermore, MR activation has been associated with worsened OSA prognosis. Despite these documented relationships, there have been no studies exploring the causal involvement of MR signaling in OSA-associated CVD. Further, scarce clinical studies have exclusively assessed the beneficial role of MR antagonists for the treatment of systemic hypertension commonly associated with OSA. Here, we provide a comprehensive overview of overlapping mechanistic pathways recruited in the context of MR activation- and OSA-induced CVD and propose MR-targeted therapy as a potential avenue to abrogate the deleterious cardiovascular consequences of OSA.

Real-world evidence for steroidal mineralocorticoid receptor antagonists in patients with chronic kidney disease

Background

Mineralocorticoid receptor antagonists (MRAs) were shown to delay chronic kidney disease (CKD) progression in patients with hypertension and/or heart failure (HF) and proteinuria.

Objective

We conducted a systematic literature review on real-world evidence to identify the literature gaps related to the efficacy and safety outcomes of MRAs administered to CKD patients.

Results

A total of 751 records were identified of which, 23 studies (26 publications) were analyzed. Studies included heterogeneous populations, including the overall CKD, CKD and diabetes, CKD and HF, and CKD and a history of cardiovascular disease. Most of the studies were small and non-rigorous, resulting in a notable lack of evidence in these populations. In the overall CKD population, steroidal MRAs resulted in a significant or sustained eGFR reduction but no efficacy in delaying progression to end-stage kidney disease. No cardiovascular protection was found. Results for all-cause mortality and hospitalization for HF were inconsistent; however, the longest follow-up studies indicate similar or lower incidence for spironolactone non-users. Most results consistently reported a higher incidence of hyperkalemia among patients on steroidal MRAs in all CKD stages, and side effects led to high discontinuation rates in the real-world setting.

Conclusions

Despite the limited availability of evidence on the effectiveness and safety of steroidal MRAs in CKD patients and subgroups with diabetes, HF or history of cardiovascular disease, MRAs were shown to have a limited effect on renal and cardiovascular outcomes. Gaps in the evidence regarding the efficacy and safety of MRAs are particularly relevant in diabetic CKD patients; therefore, further research is warranted.

Pre- and Post-Conditioning of the Heart: An Overview of Cardioprotective Signaling Pathways

Since the discovery of ischemic pre- and post-conditioning, more than 30 years ago, the knowledge about the mechanisms and signaling pathways involved in these processes has significantly increased. In clinical practice, on the other hand, such advancement has yet to be seen. This article provides an overview of ischemic pre-, post-, remote, and pharmacological conditioning related to the heart. In addition, we reviewed the cardioprotective signaling pathways and therapeutic agents involved in the above-mentioned processes, aiming to provide a comprehensive evaluation of the advancements in the field. The advancements made over the last decades cannot be ignored and with the exponential growth in techniques and applications. The future of pre- and post-conditioning is promising.