Aldosterone levels and inflammatory stimulation in essential hypertensive patients

The role of the mineralocorticoid receptor in immune cells in in cardiovascular disease

Chronic low-grade inflammation and immune cell activation are important mechanisms in the pathophysiology of cardiovascular disease (CVD). Therefore, targeted immunosuppression is a promising novel therapy to lower cardiovascular risk. In this review, we identify the mineralocorticoid receptor (MR) on immune cells as a potential target to modulate inflammation. The MR is present in almost all cells of the cardiovascular system, including immune cells. Activation of the MR in innate and adaptive immune cells induces inflammation which can contribute to CVD, by inducing endothelial dysfunction and hypertension. Moreover, it accelerates atherosclerotic plaque formation and destabilization and impairs tissue regeneration after ischemic events. Identifying the molecular targets for these non-renal actions of the MR provide promising novel cardiovascular drug targets for mineralocorticoid receptor antagonists (MRAs), which are currently mainly applied in hypertension and heart failure.

A Multicenter Study of Neutrophil-to-Lymphocyte Ratio in Primary Aldosteronism

Background

Hypertensive patients with primary aldosteronism (PA) have a higher risk of cardiovascular complications than those with blood pressure-matched essential hypertension. The excess cardiovascular consequences of PA can be attributed to the proinflammatory effect of excessive aldosterone and mineralocorticoid receptor activation in a range of peripheral tissues and cell types. The neutrophil-to-lymphocyte ratio (NLR) is a widely available marker of inflammation which has been shown to predict cardiovascular outcome in the general population. This study aims to evaluate the use of NLR as a potential biomarker of PA and PA severity.

Methods

Patients with PA (n = 355) were identified from 2 large PA databases in Australia and China, while controls (n = 222) were patients with hypertension who were referred for assessment but did not meet the diagnostic criteria for PA. The NLR was retrospectively collected from routine full blood examination, prior to commencement of targeted treatment for PA.

Results

The NLR did not differ between PA patients and hypertensive controls (median 2.3 and 2.4, P = 0.563). However, among patients with PA, the NLR was positively correlated with baseline and post-saline aldosterone levels (r = 0.22 and P < 0.001 for both) and negatively correlated with serum potassium (r = -0.15, P = 0.006). Furthermore, in a logistic regression analysis of data from patients with PA, the NLR predicted the presence of comorbid chronic kidney disease (CKD) (defined as estimated glomerular filtration rate <60 mL/min/1.73m²) with an odds ratio of 1.5 (P = 0.003).

Conclusion

While the NLR did not distinguish PA from controls, it was a marker of PA severity, being associated with aldosterone concentration as well as the presence of CKD. A prospective study is needed to further clarify the role of NLR in predicting end-organ damage associated with PA.

Interplay of pro-inflammatory cytokines, pro-inflammatory microparticles and oxidative stress and recurrent ventricular arrhythmias in elderly patients after coronary stent implantations

BACKGROUND

The roles of pro-inflammatory microparticles, pro-inflammatory cytokines and oxidative stress were unknown in elderly patients with recurrent ventricular arrhythmias (VA). We evaluated whether cross talk between oxidative stress, pro-inflammatory microparticles, and pro-inflammatory cytokines play the roles in elderly patients with recurrent VA after coronary stenting. This research sought to investigate the effects of oxidative stress, pro-inflammatory microparticles, and pro-inflammatory cytokines on recurrent VA in elderly patients after coronary stenting.

METHODS

In this study, we included 613 consecutive elderly patients with recurrent ventricular arrhythmias induced by coronary reocclusions after coronary stenting. We measured CD31⁺ endothelial microparticle (CD31⁺EMP), CD62E⁺ endothelial microparticle (CD62E⁺EMP), high-sensitivity C-reactive protein (hs-CRP), aldosterone (ALD), malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), soluble tumor necrosis factor receptor-1 (sTNFR-1) and soluble tumor necrosis factor receptor-2 (sTNFR-2) in elderly patients with recurrent VA and assessed impacts of pro-inflammatory microparticles, pro-inflammatory cytokines and oxidative stress on recurrent VA in elderly patients after coronary stenting.

RESULTS

The levels of CD31⁺EMP, CD62E⁺EMP, hs-CRP, ALD, MDA, TNF-α, sTNFR-1 and sTNFR-2 were increased in recurrent malignant ventricular arrhythmia, sustained ventricular tachycardia, multiple ventricular premature beat and left and right ventricular bundle branch block groups (P < 0.001) in elderly patients with coronary reocclusions after coronary stent implantation. Upregulation of pro-inflammatory microparticles, pro-inflammatory cytokines and oxidative stress markers induced recurrent VA in elderly patients after coronary stenting.

CONCLUSIONS

High levels of pro-inflammatory microparticles, pro-inflammatory cytokines and oxidative stress markers were associated with recurrent VA in elderly patients after coronary stenting. Our results suggested that the pro-inflammatory microparticles, pro-inflammatory cytokines and oxidative stress may simultaneously induce and aggravate recurrent VA in elderly patients after coronary stenting.

The mineralocorticoid receptor as a modulator of innate immunity and atherosclerosis

The mineralocorticoid receptor (MR) is a member of the nuclear receptor steroid-binding family. The classical MR ligand aldosterone controls electrolyte and fluid homeostasis after binding in renal epithelial cells. However, more recent evidence suggests that activation of extrarenal MRs by aldosterone negatively impacts cardiovascular health independent of its effects on blood pressure: high levels of aldosterone associate with an increased cardiovascular event rate, where MR antagonists exert beneficial effects on cardiovascular mortality. The most important cause for cardiovascular events is atherosclerosis that is currently considered a low-grade inflammatory disorder of the arterial wall. In this inflammatory process, the innate immune system plays a deciding role, with the monocyte-derived macrophage being the most abundant cell in the atherosclerotic plaque. Intriguingly, both monocytes and macrophages express the MR, and a growing body of evidence shows that these cells are skewed into a pro-inflammatory and pro-atherosclerotic phenotype via MR stimulation. In this review, we detail the current perspective on the role of the monocyte and macrophage MR in atherosclerosis development and provide a comprehensive framework of the effects of MR activation of the innate immune system that might drive the pro-atherosclerotic outcome.

Mineralocorticoid Receptors in the Pathophysiology of Vascular Inflammation and Atherosclerosis

Atherosclerosis is a chronic inflammatory disease of the vasculature that causes significant morbidity and mortality from myocardial infarction, stroke, and peripheral vascular disease. Landmark clinical trials revealed that mineralocorticoid receptor (MR) antagonists improve outcomes in cardiovascular patients. Conversely, enhanced MR activation by the hormone aldosterone is associated with increased risk of MI, stroke, and cardiovascular death. This review summarizes recent advances in our understanding of the role of aldosterone and the MR in the pathogenesis of vascular inflammation and atherosclerosis as it proceeds from risk factor-induced endothelial dysfunction and inflammation to plaque formation, progression, and ultimately rupture with thrombosis, the cause of acute ischemia. The role of the MR in converting cardiac risk factors into endothelial dysfunction, in enhancing leukocyte adhesion and infiltration into the vasculature, in promoting systemic inflammation and vascular oxidative stress, and in plaque destabilization and thrombosis are discussed. A greater understanding of the mechanisms by which the MR promotes atherosclerosis has substantial potential to identify novel treatment targets to improve cardiovascular health and decrease mortality.

Roles of inflammation, oxidative stress, and vascular dysfunction in hypertension

Hypertension is a complex condition and is the most common cardiovascular risk factor, contributing to widespread morbidity and mortality. Approximately 90% of hypertension cases are classified as essential hypertension, where the precise cause is unknown. Hypertension is associated with inflammation; however, whether inflammation is a cause or effect of hypertension is not well understood. The purpose of this review is to describe evidence from human and animal studies that inflammation leads to the development of hypertension, as well as the evidence for involvement of oxidative stress and endothelial dysfunction--both thought to be key steps in the development of hypertension. Other potential proinflammatory conditions that contribute to hypertension-such as activation of the sympathetic nervous system, aging, and elevated aldosterone--are also discussed. Finally, we consider the potential benefit of anti-inflammatory drugs and statins for antihypertensive therapy. The evidence reviewed suggests that inflammation can lead to the development of hypertension and that oxidative stress and endothelial dysfunction are involved in the inflammatory cascade. Aging and aldosterone may also both be involved in inflammation and hypertension. Hence, in the absence of serious side effects, anti-inflammatory drugs could potentially be used to treat hypertension in the future.