Modulation of the renin-angiotensin-aldosterone system in heart failure

Development and Validation of a Protein Risk Score for Mortality in Heart Failure : A Community Cohort Study

BACKGROUND

Heart failure (HF) is a complex clinical syndrome with high mortality. Current risk stratification approaches lack precision. High-throughput proteomics could improve risk prediction. Its use in clinical practice to guide the management of patients with HF depends on validation and evidence of clinical benefit.

OBJECTIVE

To develop and validate a protein risk score for mortality in patients with HF.

DESIGN

Community-based cohort.

SETTING

Southeast Minnesota.

PARTICIPANTS

Patients with HF enrolled between 2003 and 2012 and followed through 2021.

MEASUREMENTS

A total of 7289 plasma proteins in 1351 patients with HF were measured using the SomaScan Assay (SomaLogic). A protein risk score was derived using least absolute shrinkage and selection operator regression and temporal validation in patients enrolled between 2003 and 2007 (development cohort) and 2008 and 2012 (validation cohort). Multivariable Cox regression was used to examine the association between the protein risk score and mortality. The performance of the protein risk score to predict 5-year mortality risk was assessed using calibration plots, decision curves, and relative utility analyses and compared with a clinical model, including the Meta-Analysis Global Group in Chronic Heart Failure mortality risk score and N-terminal pro-B-type natriuretic peptide.

RESULTS

The development (n = 855; median age, 78 years; 50% women; 29% with ejection fraction <40%) and validation cohorts (n = 496; median age, 76 years; 45% women; 33% with ejection fraction <40%) were mostly similar. In the development cohort, 38 unique proteins were selected for the protein risk score. Independent of ejection fraction, the protein risk score demonstrated good calibration, reclassified mortality risk particularly at the extremes of the risk distribution, and showed greater clinical utility compared with the clinical model.

LIMITATION

Participants were predominantly of European ancestry, potentially limiting the generalizability of the findings to different patient populations.

CONCLUSION

Validation of the protein risk score demonstrated good calibration and evidence of predicted benefits to stratify the risk for death in HF superior to that of clinical methods. Further studies are needed to prospectively evaluate the score's performance in diverse populations and determine risk thresholds for interventions.

PRIMARY FUNDING SOURCE

Division of Intramural Research at the National Heart, Lung, and Blood Institute of the National Institutes of Health.

Biomarkers of Volume Overload and Edema in Heart Failure With Reduced Ejection Fraction

From a pathogenetic point of view, heart failure (HF) is characterized by the activation of several neurohumoral pathways with a role in maintaining the cardiac output and the adequate perfusion pressure in target organs and tissues. Decreased cardiac output in HF with reduced ejection fraction causes activation of the sympathetic nervous system, the renin angiotensin aldosterone system, arginine-vasopressin system, natriuretic peptides, and endothelin, all of which cause water and salt retention in the body. As a result, patients will present clinically as the main symptoms: dyspnea and peripheral edema caused by fluid redistribution to the lungs and/or by fluid overload. By studying these pathophysiological mechanisms, biomarkers with a prognostic and therapeutic role in the management of edema were identified in patients with HF with low ejection fraction. This review aims to summarize the current data from the specialty literature of such biomarkers with a role in the pathogenesis of edema in HF with low ejection fraction. These biomarkers may be the basis for risk stratification and the development of new therapeutic means in the treatment of edema in these patients.

From Genetic Mutations to Molecular Basis of Heart Failure Treatment: An Overview of the Mechanism and Implication of the Novel Modulators for Cardiac Myosin

Heart failure (HF) is a syndrome encompassing several important etiologies that lead to the imbalance between oxygen demand and supply. Despite the usage of guideline-directed medical therapy for HF has shown better outcomes, novel therapeutic strategies are desirable, especially for patients with preserved or mildly reduced left ventricular ejection fraction. In this regard, understanding the molecular basis for cardiomyopathies is expected to fill in the knowledge gap and generate new therapies to improve prognosis for HF. This review discusses an evolutionary mechanism designed to regulate cardiac contraction and relaxation through the most often genetically determined cardiomyopathies associated with HF. In addition, both the myosin inhibitor and myosin activator are promising new treatments for cardiomyopathies. A comprehensive review from genetic mutations to the molecular basis of direct sarcomere modulators will help shed light on future studies for a better characterization of HF etiologies and potential therapeutic targets.

Effect of Traditional Chinese Medicine Poge Heart-Saving Decoction on Cardiac Function in Heart Failure Rat Model

Background

Poge heart-saving decoction (PHSD) has been used as a medicine treating heart failure in China for many years. The study aimed to explore the effect of PHSD on cardiac function in heart failure conditions and its underlying mechanism.

Methods

Adriamycin was used to induce the model of heart failure (HF) in rats. Sixty rats were randomly divided into six groups: blank control group, sham group, 9.33 g/kg group (low-PHSD, test group), 13.995 g/kg group (moderate-PHSD, test group), 18.66 g/kg group (high-PHSD, test group), and fosinopril group (4.67 mg/kg, comparison test group). Cardiac ultrasound was used to evaluate the cardiac function of the rats, and radioimmunoassay was used to measure aldosterone (ALD) and angiotensin II (AngII) levels in the serum.

Results

Compared with the blank control group, the left ventricular end-diastolic dimension (LVEDd) and left ventricular end-systolic dimension (LVEDs) in the sham group were increased (1.04 ± 0.12 vs. 0.67 ± 0.13 cm; 0.75 ± 0.13 vs. 0.28 ± 0.10 cm; P < 0.05), and the left ventricular ejection fraction was decreased (36.65 ± 5.74 vs. 76.09 ± 4.23%; P < 0.05). The ejection fraction of HF rats was increased in 9.33 g/kg group, 13.995 g/kg group, and 18.66 g/kg group compared with those of the sham group (57.13 ± 1.63, 58.43 ± 1.98, and 59.21 ± 1.37 vs. 36.65 ± 5.74%; P < 0.05). PHSD also improved cardiac function by reducing the LVEDd and LVEDs (0.88 ± 0.11, 0.75 ± 0.13, and 0.72 ± 0.18 vs. 1.04 ± 0.12 cm; 0.62 ± 0.10, 0.63 ± 0.17, and 0.45 ± 0.11 vs. 0.75 ± 0.13 cm; P < 0.05). The levels of ALD and AngII in the serum of rats in the sham group were significantly higher than those in the blank control group (371.58 ± 39.25 vs. 237.12 ± 17.35 μg/L; 232.18 ± 16.33 vs. 159.44 ± 18.42 pg/L; P < 0.05). The ALD and AngII of the rats in all of the three PHSD groups and the fosinopril group were decreased (276.81 ± 25.63, 277.18 ± 21.35, 268.19 ± 19.28, and 271.47 ± 28.96 vs. 371.58 ± 39.25 μg/L; 169.41 ± 27.53, 168.81 ± 19.78, 164.23 ± 21.34, and 174.27 ± 22.84 vs. 232.18 ± 16.33 pg/L; P < 0.05). The histopathological changes of the myocardium in the sham group showed the disorganized fiber, shaded staining, fracture, and zonation. The fracture of the myocardium was relieved in all groups except the sham group and the blank control group.

Conclusion

Therefore, PHSD could shorten LVEDd and LVEDs of rats and reverse ventricular remodeling. The mechanism might be related to the inhibition of the activation level of renin-angiotensin-aldosterone system (especially ALD and AngII) and decreasing the postload of the heart.

QiShenYiQi pill activates autophagy to attenuate reactive myocardial fibrosis via the PI3K/AKT/mTOR pathway

QiShenYiQi pill (QSYQ), a traditional Chinese medicine, is used to treat cardiovascular diseases. However, the dose-effect relationship of its intervention in the reactive myocardial fibrosis is elusive. In this work, rat models of reactive myocardial fibrosis induced by partial abdominal aortic coarctation were constructed and randomly classified into the model group, 3-methyladenine group, rapamycin group, QSYQ low-dose group, QSYQ medium-dose group, QSYQ high-dose group, and sham-operated rats (control group). We revealed that QSYQ lowered the heart mass index (HMI), left ventricular mass index (LVMI), and myocardial collagen volume fraction (CVF) levels in a dose-dependent mechanism. Additionally, QSYQ increased the number of autophagosomes, and the expression of myocardial Beclin-1 and LC3B. In contrast, it reduced the expression of myocardial p62 and decreased the ratios of myocardial p-PI3K/PI3K, p-Akt/Akt, and p-mTOR/mTOR. In conclusion, our results have revealed that QSYQ impacts anti-reactive myocardial fibrosis in a dose-dependent mechanism which is mediated by the activation of myocardial autophagy via the PI3K/AKT/mTOR pathway.

Are SGLT-2 Inhibitors the Future of Heart Failure Treatment? The EMPEROR-Preserved and EMPEROR-Reduced Trials

Heart failure is frequently associated with diabetes, and therapies which reduce mortality in people with heart failure and reduced ejection fraction (HFrEF) are often limited to drugs which modulate the renin-angiotensin-aldosterone system or heart rate control and occasionally to device therapy. Treatment is even more challenging in people with heart failure and preserved ejection fraction (HFpEF), with currently no approved therapy demonstrating a mortality-improving effect, limiting treatment to diuretics for the alleviation of the symptoms of fluid overload and risk factor management. Previous cardiovascular outcome trials for sodium-glucose co-transporter-2 (SGLT-2) inhibitors have demonstrated significant favourable outcomes for cardiovascular disease, heart failure hospitalisation and all-cause mortality. The aim of the nearly completed EMPEROR-preserved and EMPEROR-reduced trials is to determine the impact of empagliflozin on cardiovascular and heart failure outcomes in people with HFpEF or HFrEF with or without diabetes. The trials will add substantially to our understanding of SGLT-2 inhibitors in the treatment of HFrEF and may have major implications for the treatment of people with HFpEF. The study will also be powered to address the impact of empagliflozin on changes in renal function in people with and without diabetes and incident diabetes in the participants without diabetes at baseline. In this article we discuss the rationale for using SGLT-2 inhibitors in people with heart failure and explore the potential findings and importance of the ongoing EMPEROR-preserved and EMPEROR-reduced trials.

Normalizing Plasma Renin Activity in Experimental Dilated Cardiomyopathy: Effects on Edema, Cachexia, and Survival

Heart failure (HF) patients frequently have elevated plasma renin activity. We examined the significance of elevated plasma renin activity in a translationally-relevant model of dilated cardiomyopathy (DCM), which replicates the progressive stages (A–D) of human HF. Female mice with DCM and elevated plasma renin activity concentrations were treated with a direct renin inhibitor (aliskiren) in a randomized, blinded fashion beginning at Stage B HF. By comparison to controls, aliskiren treatment normalized pathologically elevated plasma renin activity (p < 0.001) and neprilysin levels (p < 0.001), but did not significantly alter pathological changes in plasma aldosterone, angiotensin II, atrial natriuretic peptide, or corin levels. Aliskiren improved cardiac systolic function (ejection fraction, p < 0.05; cardiac output, p < 0.01) and significantly reduced the longitudinal development of edema (extracellular water, p < 0.0001), retarding the transition from Stage B to Stage C HF. The normalization of elevated plasma renin activity reduced the loss of body fat and lean mass (cachexia/sarcopenia), p < 0.001) and prolonged survival (p < 0.05). In summary, the normalization of plasma renin activity retards the progression of experimental HF by improving cardiac systolic function, reducing the development of systemic edema, cachexia/sarcopenia, and mortality. These data suggest that targeting pathologically elevated plasma renin activity may be beneficial in appropriately selected HF patients.

Renin Activity in Heart Failure with Reduced Systolic Function-New Insights

Regardless of the cause, symptomatic heart failure (HF) with reduced ejection fraction (rEF) is characterized by pathological activation of the renin–angiotensin–aldosterone system (RAAS) with sodium retention and extracellular fluid expansion (edema). Here, we review the role of active renin, a crucial, upstream enzymatic regulator of the RAAS, as a prognostic and diagnostic plasma biomarker of heart failure with reduced ejection fraction (HFrEF) progression; we also discuss its potential as a pharmacological bio-target in HF therapy. Clinical and experimental studies indicate that plasma renin activity is elevated with symptomatic HFrEF with edema in patients, as well as in companion animals and experimental models of HF. Plasma renin activity levels are also reported to be elevated in patients and animals with rEF before the development of symptomatic HF. Modulation of renin activity in experimental HF significantly reduces edema formation and the progression of systolic dysfunction and improves survival. Thus, specific assessment and targeting of elevated renin activity may enhance diagnostic and therapeutic precision to improve outcomes in appropriate patients with HFrEF.

Central Chemoreceptor Sensitivity Is Not Enhanced in Contemporary Patients With Chronic Systolic Heart Failure Receiving Optimal Treatment

BACKGROUND

Clinical and prognostic consequences of enhanced central chemosensitivity in the contemporary optimally treated patients with chronic heart failure (CHF) are unknown.

METHODS AND RESULTS

We studied central chemosensitivity (defined as hypercapnic ventilatory response [HCVR; L/min/mmHg]) in 161 CHF patients (mean left ventricular ejection fraction [LVEF] 31 ± 6%, all receiving a combination of angiotensin-converting enzyme inhibitor/angiotensin receptor blocker and beta-blocker) and 55 sex- and age-matched healthy controls. HCVR did not differ between CHF patients and controls (median 0.63 vs 0.57 L/min^-1/mmHg^-1, P = .76). When the CHF patients were divided into tertiles according to their HCVR values, there were no significant differences in clinical characteristics (except for ischemic etiology, which was more frequent in those with the highest HCVR), results of the cardiopulmonary exercise testing, and indices of heart rate variability. During the follow-up (median 28 months, range 1-48 months, ≥15 months in all survivors), 21 patients died. HCVR was not related to survival in the Cox proportional hazards analysis.

CONCLUSIONS

Central chemosensitivity is not enhanced in contemporary, optimally treated CHF patients and its assessment does not provide significant clinical or prognostic information.

Multiple comparison procedure and modeling: a versatile tool for evaluating dose-response relationships in veterinary pharmacology - a case study with furosemide

Congestive heart failure (CHF) is a leading cause of mortality with an increasing prevalence in human and canine populations. While furosemide is a loop diuretic prescribed for the majority of CHF patients to reduce fluid retention, it also activates the renin-angiotensin aldosterone system (RAAS) which further contributes to the accelerated progression of heart failure. Our objective was to quantify the effect of furosemide on diuresis, renin activity (RA), and aldosterone (AL) in dogs, using a combined multiple comparisons and model-based approach (MCP-Mod). Twenty-four healthy beagle dogs were allocated to four treatment groups (saline vs. furosemide 1, 2, and 4 mg/kg i.m., q12 h for 5 days). Data from RA and AL values at furosemide trough concentrations, as well as 24-h Diuresis, were analyzed using the MCP-Mod procedure. A combination of E_max models adequately described the dose-response relationships of furosemide for the various endpoints. The dose-response curves of RA and AL were found to be well in agreement, with an apparent shallower slope compared with 24-h Diuresis. The research presented herein constitutes the first application of MCP-Mod in Veterinary Medicine. Our data show that furosemide produces a submaximal effect on diuresis at doses lower than those identified to activate the circulating RAAS.

Combination of angiotensin II and l-NG-nitroarginine methyl ester exacerbates mitochondrial dysfunction and oxidative stress to cause heart failure

Mitochondrial dysfunction has been implicated as a cause of energy deprivation in heart failure (HF). Herein, we tested individual and combined effects of two pathogenic factors of nonischemic HF, inhibition of nitric oxide synthesis [with l-N(G)-nitroarginine methyl ester (l-NAME)] and hypertension [with angiotensin II (AngII)], on myocardial mitochondrial function, oxidative stress, and metabolic gene expression. l-NAME and AngII were administered individually and in combination to mice for 5 wk. Although all treatments increased blood pressure and reduced cardiac contractile function, the l-NAME + AngII group was associated with the most severe HF, as characterized by edema, hypertrophy, oxidative stress, increased expression of Nppa and Nppb, and decreased expression of Atp2a2 and Camk2b. l-NAME + AngII-treated mice exhibited robust deterioration of cardiac mitochondrial function, as observed by reduced respiratory control ratios in subsarcolemmal mitochondria and reduced state 3 levels in interfibrillar mitochondria for complex I but not for complex II substrates. Cardiac myofibrils showed reduced ADP-supported and oligomycin-inhibited oxygen consumption. Mitochondrial functional impairment was accompanied by reduced mitochondrial DNA content and activities of pyruvate dehydrogenase and complex I but increased H2O2 production and tissue protein carbonyls in hearts from AngII and l-NAME + AngII groups. Microarray analyses revealed the majority of the gene changes attributed to the l-NAME + AngII group. Pathway analyses indicated significant changes in metabolic pathways, such as oxidative phosphorylation, mitochondrial function, cardiac hypertrophy, and fatty acid metabolism in l-NAME + AngII hearts. We conclude that l-NAME + AngII is associated with impaired mitochondrial respiratory function and increased oxidative stress compared with either l-NAME or AngII alone, resulting in nonischemic HF.

What can we learn about treating heart failure from the heart's response to acute exercise? Focus on the coronary microcirculation

Coronary microvascular function and cardiac function are closely related in that proper cardiac function requires adequate oxygen delivery through the coronary microvasculature. Because of the close proximity of cardiomyocytes and coronary microvascular endothelium, cardiomyocytes not only communicate their metabolic needs to the coronary microvasculature, but endothelium-derived factors also directly modulate cardiac function. This review summarizes evidence that the myocardial oxygen balance is disturbed in the failing heart because of increased extravascular compressive forces and coronary microvascular dysfunction. The perturbations in myocardial oxygen balance are exaggerated during exercise and are due to alterations in neurohumoral influences, endothelial function, and oxidative stress. Although there is some evidence from animal studies that the myocardial oxygen balance can partly be restored by exercise training, it is largely unknown to what extent the beneficial effects of exercise training include improvements in endothelial function and/or oxidative stress in the coronary microvasculature and how these improvements are impacted by risk factors such as diabetes, obesity, and hypercholesterolemia.

Identification of the Vasoconstriction-Inhibiting Factor (VIF), a Potent Endogenous Cofactor of Angiotensin II Acting on the Angiotensin II Type 2 Receptor

BACKGROUND

The renin-angiotensin system and especially the angiotensin peptides play a central role in blood pressure regulation. Here, we hypothesize that an as-yet unknown peptide is involved in the action of angiotensin II modulating the vasoregulatory effects as a cofactor.

METHODS AND RESULTS

The peptide with vasodilatory properties was isolated from adrenal glands chromatographically. The effects of this peptide were evaluated in vitro and in vivo, and the receptor affinity was analyzed. The plasma concentration in humans was quantified in patients with chronic kidney disease, patients with heart failure, and healthy control subjects. The amino acid sequence of the peptide from bovine adrenal glands was HSSYEDELSEVL EKPNDQAE PKEVTEEVSSKDAAE, which is a degradation product of chromogranin A. The sequence of the peptide isolated from human plasma was HSGFEDELSEVLENQSSQAELKEAVEEPSSKDVME. Both peptides diminished significantly the vasoconstrictive effect of angiotensin II in vitro. Therefore, we named the peptide vasoconstriction-inhibiting factor (VIF). The vasoregulatory effects of VIF are mediated by the angiotensin II type 2 receptor. VIF impairs angiotensin II-induced phosphorylation of the p38 mitogen-activated protein kinase pathway but not of extracellular-regulated kinase 1/2. The vasodilatory effects were confirmed in vivo. The plasma concentration was significantly increased in renal patients and patients with heart failure.

CONCLUSIONS

VIF is a vasoregulatory peptide that modulates the vasoconstrictive effects of angiotensin II by acting on the angiotensin II type 2 receptor. It is likely that the increase in VIF may serve as a counterregulatory effect to defend against hypertension. The identification of this target may help us to understand the pathophysiology of renal and heart failure and may form a basis for the development of new strategies for the prevention and treatment of cardiovascular disease.