The role of mineralocorticoid receptor antagonists (MRAs) in very old patients with heart failure

Frailty, Sarcopenia, Cachexia, and Malnutrition in Heart Failure

With global aging, the number of patients with heart failure has increased markedly. Heart failure is a complex condition intricately associated with aging, organ damage, frailty, and cognitive decline, resulting in a poor prognosis. The relationship among frailty, sarcopenia, cachexia, malnutrition, and heart failure has recently received considerable attention. Although these conditions are distinct, they often exhibit a remarkably close relationship. Overlapping diagnostic criteria have been observed in the recently proposed guidelines and position statements, suggesting that several of these conditions may coexist in patients with heart failure. Therefore, a comprehensive understanding of these conditions is essential, and interventions must not only target these conditions individually, but also provide comprehensive management strategies. This review article provides an overview of the epidemiology, diagnostic methods, overlap, and prognosis of frailty, sarcopenia, cachexia, and malnutrition in patients with heart failure, incorporating insights from the FRAGILE-HF study data. Additionally, based on existing literature, this article discusses the impact of these conditions on the effectiveness of guideline-directed medical therapy for patients with heart failure. While recognizing these conditions early and promptly implementing interventions may be advantageous, further data, particularly from well-powered, large-scale, randomized controlled trials, are necessary to refine personalized treatment strategies for patients with heart failure.

Proteomic Analysis of Hypoxia-Induced Senescence of Human Bone Marrow Mesenchymal Stem Cells

Methods

Hypoxia in hBMSCs was induced for 0, 4, and 12 hours, and cellular senescence was evaluated by senescence-associated β-galactosidase (SA-β-gal) staining. Tandem mass tag (TMT) labeling was combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) for differential proteomic analysis of hypoxia in hBMSCs. Parallel reaction monitoring (PRM) analysis was used to validate the candidate proteins. Verifications of signaling pathways were evaluated by western blotting. Cell apoptosis was evaluated using Annexin V/7-AAD staining by flow cytometry. The production of reactive oxygen species (ROS) was detected by the fluorescent probe 2,7-dichlorodihydrofluorescein diacetate (DCFH-DA).

Results

Cell senescence detected by SA-β-gal activity was higher in the 12-hour hypoxia-induced group. TMT analysis of 12-hour hypoxia-induced cells identified over 6000 proteins, including 686 differentially expressed proteins. Based on biological pathway analysis, we found that the senescence-associated proteins were predominantly enriched in the cancer pathways, PI3K-Akt pathway, and cellular senescence signaling pathways. CDK1, CDK2, and CCND1 were important nodes in PPI analyses. Moreover, the CCND1, UQCRH, and COX7C expressions were verified by PRM. Hypoxia induction for 12 hours in hBMSCs reduced CCND1 expression but promoted ROS production and cell apoptosis. Such effects were markedly reduced by the PI3K agonist, 740 Y-P, and attenuated by LY294002.

Conclusions

Hypoxia of hBMSCs inhibited CCND1 expression but promoted ROS production and cell apoptosis through activating the PI3K-dependent signaling pathway. These findings provided a detailed characterization of the proteomic profiles related to hypoxia-induced senescence of hBMSCs and facilitated our understanding of the molecular mechanisms leading to stem cell senescence.

Posttranslational Modifications of the Mineralocorticoid Receptor and Cardiovascular Aging

During aging, the cardiovascular system is especially prone to a decline in function and to life-expectancy limiting diseases. Cardiovascular aging is associated with increased arterial stiffness and vasoconstriction as well as left ventricular hypertrophy and reduced diastolic function. Pathological changes include endothelial dysfunction, atherosclerosis, fibrosis, hypertrophy, inflammation, and changes in micromilieu with increased production of reactive oxygen and nitrogen species. The renin-angiotensin-aldosterone-system is an important mediator of electrolyte and blood pressure homeostasis and a key contributor to pathological remodeling processes of the cardiovascular system. Its effects are partially conveyed by the mineralocorticoid receptor (MR), a ligand-dependent transcription factor, whose activity increases during aging and cardiovascular diseases without correlating changes of its ligand aldosterone. There is growing evidence that the MR can be enzymatically and non-enzymatically modified and that these modifications contribute to ligand-independent modulation of MR activity. Modifications reported so far include phosphorylation, acetylation, ubiquitination, sumoylation and changes induced by nitrosative and oxidative stress. This review focuses on the different posttranslational modifications of the MR, their impact on MR function and degradation and the possible implications for cardiovascular aging and diseases.

Prognostic impact of additional mineralocorticoid receptor antagonists in octogenarian heart failure patients

AIMS

Guideline-directed medical therapy (GDMT) including beta-blockers and renin-angiotensin system inhibitors is shown to reduce mortality risk in patients with heart failure (HF) and reduced left ventricular ejection fraction (LVEF). However, there is little evidence about the efficacy of additional administration of mineralocorticoid receptor antagonists (MRAs) with GDMT in patients ≥80 years presenting with HF. We aimed to investigate the prognostic impact of GDMT with MRA in relation to the age of patients with HF.

METHODS AND RESULTS

This observational study included patients admitted for HF with reduced LVEF who were discharged alive; among them, 224 patients were ≥80 years, and 661 patients were <80 years. Both populations were divided into three groups depending on whether they received GDMT with or without MRA or single/no GDMT drugs (GDMT+MRA+, GDMT+MRA-, or non-GDMT, respectively). The primary endpoint was all-cause mortality. In patients ≥80 years, all-cause mortality was the lowest in the GDMT+MRA+ group (log-rank trend, P = 0.034), and no significant differences were observed between the GDMT+MRA- and non-GDMT groups. Multivariate Cox regression analysis revealed that GDMT+MRA+ was superior to GDMT+MRA-, even after adjusting for parameters at discharge (hazard ratio: 0.32, 95% confidence interval: 0.11-0.99). In patients <80 years, GDMT reduced all-cause mortality; however, additional MRA was not associated with an improved outcome.

CONCLUSIONS

The results of this study suggest that additional MRA to GDMT at discharge is one of the therapeutic options for elderly HF patients with reduced LVEF. This finding is not well documented in previous clinical trials.

Mineralocorticoid Receptor Signaling Contributes to Normal Muscle Repair After Acute Injury

Acute skeletal muscle injury is followed by a temporal response of immune cells, fibroblasts, and muscle progenitor cells within the muscle microenvironment to restore function. These same cell types are repeatedly activated in muscular dystrophy from chronic muscle injury, but eventually, the regenerative portion of the cycle is disrupted and fibrosis replaces degenerated muscle fibers. Mineralocorticoid receptor (MR) antagonist drugs have been demonstrated to increase skeletal muscle function, decrease fibrosis, and directly improve membrane integrity in muscular dystrophy mice, and therefore are being tested clinically. Conditional knockout of MR from muscle fibers in muscular dystrophy mice also improves skeletal muscle function and decreases fibrosis. The mechanism of efficacy likely results from blocking MR signaling by its endogenous agonist aldosterone, being produced at high local levels in regions of muscle damage by infiltrating myeloid cells. Since chronic and acute injuries share the same cellular processes to regenerate muscle, and MR antagonists are clinically used for a wide variety of conditions, it is crucial to define the role of MR signaling in normal muscle repair after injury. In this study, we performed acute injuries using barium chloride injections into tibialis anterior muscles both in myofiber MR conditional knockout mice on a wild-type background (MRcko) and in MR antagonist-treated wild-type mice. Steps of the muscle regeneration response were analyzed at 1, 4, 7, or 14 days after injury. Presence of the aldosterone synthase enzyme was also assessed during the injury repair process. We show for the first time aldosterone synthase localization in infiltrating immune cells of normal skeletal muscle after acute injury. MRcko mice had an increased muscle area infiltrated by aldosterone synthase positive myeloid cells compared to control injured animals. Both MRcko and MR antagonist treatment stabilized damaged myofibers and increased collagen infiltration or compaction at 4 days post-injury. MR antagonist treatment also led to reduced myofiber size at 7 and 14 days post-injury. These data support that MR signaling contributes to the normal muscle repair process following acute injury. MR antagonist treatment delays muscle fiber growth, so temporary discontinuation of these drugs after a severe muscle injury could be considered.

Role of Aldosterone and Mineralocorticoid Receptor in Cardiovascular Aging

The mineralocorticoid receptor (MR) was originally identified as a regulator of blood pressure, able to modulate renal sodium handling in response to its principal ligand aldosterone. MR is expressed in several extra-renal tissues, including the heart, vasculature, and adipose tissue. More recent studies have shown that extra-renal MR plays a relevant role in the control of cardiovascular and metabolic functions and has recently been implicated in the pathophysiology of aging. MR activation promotes vasoconstriction and acts as a potent pro-fibrotic agent in cardiovascular remodeling. Aging is associated with increased arterial stiffness and vascular tone, and modifications of arterial structure and function are responsible for these alterations. MR activation contributes to increase blood pressure with aging by regulating myogenic tone, vasoconstriction, and vascular oxidative stress. Importantly, aging represents an important contributor to the increased prevalence of cardiometabolic syndrome. In the elderly, dysregulation of MR signaling is associated with hypertension, obesity, and diabetes, representing an important cause of increased cardiovascular risk. Clinical use of MR antagonists is limited by the adverse effects induced by MR blockade in the kidney, raising the risk of hyperkalaemia in older patients with reduced renal function. Therefore, there is an unmet need for the enhanced understanding of the role of MR in aging and for development of novel specific MR antagonists in the context of cardiovascular rehabilitation in the elderly, in order to reduce relevant side effects.

Emerging Roles of the Mineralocorticoid Receptor in Pathology: Toward New Paradigms in Clinical Pharmacology

The mineralocorticoid receptor (MR) and its ligand aldosterone are the principal modulators of hormone-regulated renal sodium reabsorption. In addition to the kidney, there are several other cells and organs expressing MR, in which its activation mediates pathologic changes, indicating potential therapeutic applications of pharmacological MR antagonism. Steroidal MR antagonists have been used for decades to fight hypertension and more recently heart failure. New therapeutic indications are now arising, and nonsteroidal MR antagonists are currently under development. This review is focused on nonclassic MR targets in cardiac, vascular, renal, metabolic, ocular, and cutaneous diseases. The MR, associated with other risk factors, is involved in organ fibrosis, inflammation, oxidative stress, and aging; for example, in the kidney and heart MR mediates hormonal tissue-specific ion channel regulation. Genetic and epigenetic modifications of MR expression/activity that have been documented in hypertension may also present significant risk factors in other diseases and be susceptible to MR antagonism. Excess mineralocorticoid signaling, mediated by aldosterone or glucocorticoids binding, now appears deleterious in the progression of pathologies that may lead to end-stage organ failure and could therefore benefit from the repositioning of pharmacological MR antagonists.

Baseline characteristics of patients in the treatment of preserved cardiac function heart failure with an aldosterone antagonist trial

BACKGROUND

Treatment of Preserved Cardiac Function with an Aldosterone Antagonist (TOPCAT) is an ongoing randomized controlled trial of spironolactone versus placebo for heart failure with preserved ejection fraction (HFpEF). We sought to describe the baseline clinical characteristics of subjects enrolled in TOPCAT relative to other contemporary observational studies and randomized clinical trials of HFpEF.

METHODS AND RESULTS

Between August 2006 and January 2012, 3445 patients with symptomatic HFpEF from 270 sites in 6 countries were enrolled in TOPCAT. At the baseline study visit, all subjects provided a detailed medical history and underwent physical examination, electrocardiography, quality of life, and laboratory assessment. Key parameters were compared with other large, contemporary HFpEF studies. The mean age was 68.6±9.6 years with a slight female predominance (52%); mean body mass index was 32 kg/m2; and comorbidities were common. History of hypertension (91% prevalence in TOPCAT) exceeded all other major HFpEF clinical trials. However, baseline blood pressure was well controlled (129/76 mm Hg; systolic blood pressure 7-16 mm Hg lower than other similar trials). Other common comorbidities included coronary artery disease (57%), atrial fibrillation (35%), chronic kidney disease (38%) and diabetes mellitus (32%). Self-reported activity levels were low, quality of life scores were comparable with those reported for patients with end-stage renal disease, and the prevalence of moderate or greater depression was 27%.

CONCLUSIONS

TOPCAT subjects share many common characteristics with contemporary HFpEF cohorts. Low activity level, significantly decreased quality of life, and depression were common at baseline in TOPCAT, underscoring the continued unmet need for evidence-based treatment strategies in HFpEF.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. UNIQUE IDENTIFIER: NCT00094302.