Mineralocorticoid receptor antagonist treatment of established pulmonary arterial hypertension improves interventricular dependence in the SU5416-hypoxia rat model

Current Overview of the Biology and Pharmacology in Sugen/Hypoxia-Induced Pulmonary Hypertension in Rats

The Sugen 5416/hypoxia (Su/Hx) rat model of pulmonary arterial hypertension (PAH) demonstrates most of the distinguishing features of PAH in humans, including increased wall thickness and obstruction of the small pulmonary arteries along with plexiform lesion formation. Recently, significant advancement has been made describing the epidemiology, genomics, biochemistry, physiology, and pharmacology in Su/Hx challenge in rats. For example, there are differences in the overall reactivity to Su/Hx challenge in different rat strains and only female rats respond to estrogen treatments. These conditions are also encountered in human subjects with PAH. Also, there is a good translation in both the biochemical and metabolic pathways in the pulmonary vasculature and right heart between Su/Hx rats and humans, particularly during the transition from the adaptive to the nonadaptive phase of right heart failure. Noninvasive techniques such as echocardiography and magnetic resonance imaging have recently been used to evaluate the progression of the pulmonary vascular and cardiac hemodynamics, which are important parameters to monitor the efficacy of drug treatment over time. From a pharmacological perspective, most of the compounds approved clinically for the treatment of PAH are efficacious in Su/Hx rats. Several compounds that show efficacy in Su/Hx rats have advanced into phase II/phase III studies in humans with positive results. Results from these drug trials, if successful, will provide additional treatment options for patients with PAH and will also further validate the excellent translation that currently exists between Su/Hx rats and the human PAH condition.

Management of Pulmonary Hypertension in the Context of Heart Failure with Preserved Ejection Fraction

PURPOSE OF REVIEW

To review the current evidence and modalities for treating pulmonary hypertension (PH) in heart failure with preserved ejection fraction (HFpEF).

RECENT FINDINGS

In recent years, several therapies have been developed that improve morbidity in HFpEF, though these studies have not specifically studied patients with PF-HFpEF. Multiple trials of therapies specifically targeting the pulmonary vasculature such as phosphodiesterase (PDE) inhibitors, prostacyclin analogs, endothelin receptor antagonists (ERA), and soluble guanylate cyclase stimulators have also been conducted. However, these therapies demonstrated lack of consistency in improving hemodynamics or functional outcomes in PH-HFpEF. There is limited evidence to support the use of pulmonary vasculature-targeting therapies in PH-HFpEF. The mainstay of therapy remains the treatment of the underlying HFpEF condition. There is emerging evidence that newer HF therapies such as sodium-glucose transporter 2 inhibitors and angiotensin-receptor-neprilysin inhibitors are associated with improved hemodynamics and quality of life of patients with PH-HFpEF. There is also a growing realization that more robust phenotyping PH and right ventricular (RV) function may hold promise for therapeutic strategies for patients with PH-HFpEF.

Recent progress in unraveling cardiovascular complications associated with primary aldosteronism: a succinct review

This comprehensive review offers a thorough exploration of recent advancements in our understanding of the intricate cardiovascular complications associated with Primary Aldosteronism (PA). PA encompasses a spectrum of conditions characterized by hypertension and excessive production of aldosterone operating independently of the renin-angiotensin system. Given its association with an elevated risk of cardiovascular and cerebrovascular complications, as well as a higher incidence of metabolic syndrome in comparison to individuals with essential hypertension (EH), an accurate diagnosis of PA is of paramount importance. This review delves into the intricate interplay between PA and cardiovascular health and focuses on the key pathophysiological mechanisms contributing to adverse cardiac outcomes. The impact of different treatment modalities on cardiovascular health is also examined, offering insights into potential therapeutic approaches. By highlighting the significance of recognizing PA as a significant contributor to cardiovascular morbidity, this review emphasizes the need for improved screening, early diagnosis, and tailored management strategies to both enhance patient care and mitigate the burden of cardiovascular diseases. The findings presented herein underscore the growing importance of PA in the context of cardiovascular medicine and emphasize the potential for translating these insights into targeted interventions to improve patient outcomes.

Mineralocorticoid Receptors in Vascular Smooth Muscle: Blood Pressure and Beyond

After half a century of evidence suggesting the existence of mineralocorticoid receptors (MR) in the vasculature, the advent of technology to specifically knockout the MR from smooth muscle cells (SMCs) in mice has elucidated contributions of SMC-MR to cardiovascular function and disease, independent of the kidney. This review summarizes the latest understanding of the molecular mechanisms by which SMC-MR contributes to (1) regulation of vasomotor function and blood pressure to contribute to systemic and pulmonary hypertension; (2) vascular remodeling in response to hypertension, vascular injury, obesity, and aging, and the impact on vascular calcification; and (3) cardiovascular pathologies including aortic aneurysm, heart valve dysfunction, and heart failure. Data are reviewed from in vitro studies using SMCs and in vivo findings from SMC-specific MR-knockout mice that implicate target genes and signaling pathways downstream of SMC-MR. By regulating expression of the L-type calcium channel subunit Cav1.2 and angiotensin II type-1 receptor, SMC-MR contributes to myogenic tone and vasoconstriction, thereby contributing to systemic blood pressure. MR activation also promotes SMC proliferation, migration, production and degradation of extracellular matrix, and osteogenic differentiation by regulating target genes including connective tissue growth factor, osteopontin, bone morphogenetic protein 2, galectin-3, and matrix metallopeptidase-2. By these mechanisms, SMC-MR promotes disease progression in models of aging-associated vascular stiffness, vascular calcification, mitral and aortic valve disease, pulmonary hypertension, and heart failure. While rarely tested, when sexes were compared, the mechanisms of SMC-MR-mediated disease were sexually dimorphic. These advances support targeting SMC-MR-mediated mechanisms to prevent and treat diverse cardiovascular disorders.

Therapeutic targeting of mineralocorticoid receptors in pulmonary hypertension: Insights from basic research

Pulmonary hypertension (PH) is characterized by pulmonary vascular remodeling and associated with adverse outcomes. In patients with PH, plasma aldosterone levels are elevated, suggesting that aldosterone and its receptor, the mineralocorticoid receptor (MR), play an important role in the pathophysiology of PH. The MR plays a crucial role in adverse cardiac remodeling in left heart failure. A series of experimental studies from the past few years indicate that MR activation promotes adverse cellular processes that lead to pulmonary vascular remodeling, including endothelial cell apoptosis, smooth muscle cell (SMC) proliferation, pulmonary vascular fibrosis, and inflammation. Accordingly, in vivo studies have demonstrated that pharmacological inhibition or cell-specific deletion of the MR can prevent disease progression and partially reverse established PH phenotypes. In this review, we summarize recent advances in MR signaling in pulmonary vascular remodeling based on preclinical research and discuss the potential, but also the challenges, in bringing MR antagonists (MRAs) into clinical application.

Emerging vascular cell-specific roles for mineralocorticoid receptor: implications for understanding sex differences in cardiovascular disease

As growing evidence implicates extrarenal mineralocorticoid receptor (MR) in cardiovascular disease (CVD), recent studies have defined both cell- and sex-specific roles. MR is expressed in vascular smooth muscle (SMC) and endothelial cells (ECs). This review integrates published data from the past 5 years to identify novel roles for vascular MR in CVD, with a focus on understanding sex differences. Four areas are reviewed in which there is recently expanded understanding of the cell type- or sex-specific role of MR in 1) obesity-induced microvascular endothelial dysfunction, 2) vascular inflammation in atherosclerosis, 3) pulmonary hypertension, and 4) chronic kidney disease (CKD)-related CVD. The review focuses on preclinical data on each topic describing new mechanistic paradigms, cell type-specific mechanisms, sexual dimorphism if addressed, and clinical implications are then considered. New data support that MR drives vascular dysfunction induced by cardiovascular risk factors via sexually dimorphic mechanisms. In females, EC-MR contributes to obesity-induced endothelial dysfunction by regulating epithelial sodium channel expression and by inhibiting estrogen-induced nitric oxide production. In males with hyperlipidemia, EC-MR promotes large vessel inflammation by genomic regulation of leukocyte adhesion molecules, which is inhibited by the estrogen receptor. In pulmonary hypertension models, MRs in EC and SMC contribute to distinct components of disease pathologies including pulmonary vessel remodeling and RV dysfunction. Despite a female predominance in pulmonary hypertension, sex-specific roles for MR have not been explored. Vascular MR has also been directly implicated in CKD-related vascular dysfunction, independent of blood pressure. Despite these advances, sex differences in MR function remain understudied.