Plasma nitric oxide level in heart failure secondary to left ventricular diastolic dysfunction

C-Reactive Protein, Interleukin-6, Trimethylamine-N-Oxide, Syndecan-1, Nitric Oxide, and Tumor Necrosis Factor Receptor-1 in Heart Failure with Preserved Versus Reduced Ejection Fraction: a Meta-Analysis

PURPOSE OF REVIEW

The purpose of this review was to synthesize the evidence on non-traditional biomarkers from proteomic and metabolomic studies that may distinguish heart failure (HF) with preserved ejection fraction (HFpEF) from heart failure with reduced ejection fraction (HFrEF) and non-HF.

RECENT FINDINGS

Understanding the pathophysiology of HFpEF continues to be challenging. A number of inflammatory and metabolic biomarkers that have recently been suggested to be involved include C-reactive protein (CRP), interleukin-6 (IL-6), trimethylamine-N-oxide (TMAO), syndecan-1 (SDC-1), nitric oxide (NO), and tumor necrosis factor receptor-1 (TNFR-1). A systematic search was conducted using Medline, EMBASE, and Web of Science with search terms such as "HFpEF," "metabolomics," and "proteomics," and a meta-analysis was conducted. The results demonstrate significantly higher levels of TMAO, CRP, SDC-1, and IL-6 in HFpEF compared to controls without HF and significantly higher levels of TMAO and CRP in HFrEF compared to controls. The results further suggest that HFpEF might be distinguishable from HFrEF based on higher levels of IL-6 and lower levels of SDC-1 and NO. These data may reflect pathophysiological differences between HFpEF and HFrEF.

Biomarkers for Heart Failure in Asia

Contributions from the Asian biomedical community to knowledge of biomarkers in heart failure have grown rapidly since 2000. Japan has made world-leading contributions in the discovery and application of cardiac natriuretic peptides as biomarkers in heart failure, but there has been rapid growth in reports from China. Contributions also come from Taiwan, South Korea, Singapore, and Hong Kong. Centers in Asia have established clinical cohorts providing powerful platforms for the discovery and validation of biomarkers in heart failure. This century, Asian enquiry into biomarkers in heart failure will include peptides, cytokines, metabolites, nucleic acids, and other analytes.

The NO/ONOO-cycle as the central cause of heart failure

The NO/ONOO-cycle is a primarily local, biochemical vicious cycle mechanism, centered on elevated peroxynitrite and oxidative stress, but also involving 10 additional elements: NF-κB, inflammatory cytokines, iNOS, nitric oxide (NO), superoxide, mitochondrial dysfunction (lowered energy charge, ATP), NMDA activity, intracellular Ca(2+), TRP receptors and tetrahydrobiopterin depletion. All 12 of these elements have causal roles in heart failure (HF) and each is linked through a total of 87 studies to specific correlates of HF. Two apparent causal factors of HF, RhoA and endothelin-1, each act as tissue-limited cycle elements. Nineteen stressors that initiate cases of HF, each act to raise multiple cycle elements, potentially initiating the cycle in this way. Different types of HF, left vs. right ventricular HF, with or without arrhythmia, etc., may differ from one another in the regions of the myocardium most impacted by the cycle. None of the elements of the cycle or the mechanisms linking them are original, but they collectively produce the robust nature of the NO/ONOO-cycle which creates a major challenge for treatment of HF or other proposed NO/ONOO-cycle diseases. Elevated peroxynitrite/NO ratio and consequent oxidative stress are essential to both HF and the NO/ONOO-cycle.

Diminished global arginine bioavailability as a metabolic defect in chronic systolic heart failure

BACKGROUND

Systemic alterations in arginine bioavailability occur in heart failure (HF) patients with more advanced myocardial dysfunction and poorer clinical outcomes, and they improve with beta-blocker therapy.

METHODS AND RESULTS

We measured fasting plasma levels of L-arginine and related biogenic amine metabolites in 138 stable symptomatic HF patients with left ventricular ejection fraction ≤35% and comprehensive echocardiographic evaluation. Long-term adverse clinical outcomes (death and cardiac transplantation) were followed for 5 years. Lower global arginine bioavailability ratio (GABR; ratio of L-arginine to L-ornithine + L-citrulline) was associated with higher plasma natriuretic peptide levels, more advanced left ventricular diastolic dysfunction, and more severe right ventricular systolic dysfunction (all P < .001). Patients taking beta-blockers had significantly higher GABR than those not taking beta-blockers (0.86 [interquartile range (IQR) 0.68-1.17] vs 0.61 [0.44-0.89]; P < .001). Subjects with higher GABR experienced fewer long-term adverse clinical events (hazard ratio 0.61 [95% confidence interval 0.43-0.84]; P = .002). In an independent beta-blocker naïve patient cohort, GABR increased following long-term (6 month) beta-blocker therapy (0.89 [IQR 0.52-1.07] to 0.97 [0.81-1.20]; P = .019).

CONCLUSIONS

In patients with chronic systolic heart failure, diminished global L-arginine bioavailability is associated with more advanced myocardial dysfunction and poorer long-term adverse clinical outcomes. GABR levels improved with beta-blocker therapy.

The role of exercise on L-arginine nitric oxide pathway in chronic heart failure

Chronic heart failure (CHF) is a pathological state with high morbidity and mortality and the full understanding of its genesis remain to be elucidated. In this syndrome, a cascade of neurohormonal and hemodynamic mechanisms, as well as inflammatory mediators, are activated to improve the impaired cardiac function. Clinical and experimental observations have shown that CHF is associated with a generalized disturbance in endothelium-dependent vasodilation, which may contribute to the progression of ventricular and vascular remodelling in this syndrome. There is also accumulating evidence that disturbances in nitric oxide (NO) availability is involved in the development of heart failure at the systemic and cardiac levels. NO is a ubiquitous signalling molecule which causes potent vasodilation, inhibits platelet activation and regulates the contractile properties of cardiac myocytes. It is generated from the amino acid L-arginine via constitutive and inducible isoforms of the enzyme NO synthase (NOS). There is evidence that exercise, a nonpharmacological tool, improves symptoms, fitness (VO_2peak), quality of life and NO bioavailability in CHF population. This review examines different aspects of the L-arginine-NO pathway and inflammation in the physiopathology of CHF and highlights the important beneficial effects of exercise in this disease.

Recent advances in the understanding of the role of nitric oxide in cardiovascular homeostasis

Nitric oxide synthases (NOS) are the enzymes responsible for nitric oxide (NO) generation. To date, 3 distinct NOS isoforms have been identified: neuronal NOS (NOS1), inducible NOS (NOS2), and endothelial NOS (NOS3). Biochemically, NOS consists of a flavin-containing reductase domain, a heme-containing oxygenase domain, and regulatory sites. NOS catalyse an overall 5-electron oxidation of one Nomega-atom of the guanidino group of L-arginine to form NO and L-citrulline. NO exerts a plethora of biological effects in the cardiovascular system. The basal formation of NO in mitochondria by a mitochondrial NOS seems to be one of the main regulators of cellular respiration, mitochondrial transmembrane potential, and transmembrane proton gradient. This review focuses on recent advances in the understanding of the role of enzyme and enzyme-independent NO formation, regulation of NO bioactivity, new aspects of NO on cardiac function and morphology, and the clinical impact and perspectives of these recent advances in our knowledge on NO-related pathways.

Celiprolol, A Vasodilatory β-Blocker, Inhibits Pressure Overload–Induced Cardiac Hypertrophy and Prevents the Transition to Heart Failure via Nitric Oxide–Dependent Mechanisms in Mice

Background— The blockade of β-adrenergic receptors reduces both mortality and morbidity in patients with chronic heart failure, but the cellular mechanism remains unclear. Celiprolol, a selective β 1 -blocker, was reported to stimulate the expression of endothelial NO synthase (eNOS) in the heart, and NO levels have been demonstrated to be related to myocardial hypertrophy and heart failure. Thus, we aimed to clarify whether celiprolol attenuates both myocardial hypertrophy and heart failure via the NO-signal pathway.

Methods and Results— In rat neonatal cardiac myocytes, celiprolol inhibited protein synthesis stimulated by either isoproterenol or phenylephrine, which was partially suppressed by N G -nitro- l -arginine methyl ester (L-NAME). Four weeks after transverse aortic constriction (TAC) in C57BL/6 male mice, the ratio of heart weight to body weight (mg/g) (8.70±0.42 in TAC, 6.61±0.44 with celiprolol 100 mg · kg −1 · d −1 PO, P <0.01) and the ratio of lung weight to body weight (mg/g) (10.27±1.08 in TAC, 7.11±0.70 with celiprolol 100 mg · kg −1 · d −1 PO, P <0.05) were lower and LV fractional shortening was higher in the celiprolol-treated groups than in the TAC group. All of these improvements were blunted by L-NAME. Celiprolol treatment significantly increased myocardial eNOS and activated phosphorylation of eNOS. Myocardial mRNA levels of natriuretic peptide precursor type B and protein inhibitor of NO synthase, which were increased in the TAC mice, were decreased in the celiprolol-treated mice.

Conclusions— These findings indicated that celiprolol attenuates cardiac myocyte hypertrophy both in vitro and in vivo and halts the process leading from hypertrophy to heart failure. These effects are mediated by a selective β 1 -adrenergic receptor blockade and NO-dependent pathway.

Effect of a cardiac rehabilitation program on left ventricular diastolic function and its relationship to exercise capacity in patients with coronary heart disease: experience from a randomized, controlled study

BACKGROUND

A cardiac rehabilitation and prevention program (CRPP) is a recognized nonpharmacological modality in the management of coronary heart disease (CHD). However, the effect of a CRPP on systolic function of the heart is controversial, and no data exists on diastolic function in CHD. A randomized, controlled study was conducted to address these issues.

METHODS

Patients (n = 269) with recent acute myocardial infarction (n = 193) or after percutaneous coronary intervention (PCI) (n = 76) were randomized to either CRPP (2-hour twice-weekly exercise program for 8 weeks) or conventional therapy (control group). Serial treadmill exercise testing and at-rest echocardiography were performed during phases 1 (baseline), 2 (post-exercise training), and 3 (8-month follow up).

RESULTS

The prevalence of left ventricular (LV) abnormal relaxation pattern (ARP) of diastolic dysfunction was increased in the control group only in phase 3 (65% vs 88%, chi2 = 7.6, P <.01). Significant improvement of individual LV diastolic parameters towards less severe delayed relaxation was also observed in the CRPP group, especially in those with recent acute myocardial infarction or ARP. The gain in exercise capacity was faster and more substantial in the CRPP than the control group (P <.001 for phase 2, P <.05 for phase 3), and was significantly correlated with LV diastolic indices in those with ARP. Exercise training had neutral effects on LV systolic function and rate-pressure product.

CONCLUSIONS

In patients with CHD, CRPP prevented the progression of resting LV diastolic dysfunction, without affecting systolic function. In those with ARP, the improvement of diastolic function predicted the gain in exercise capacity.

Nitric oxide and cardiac function: ten years after, and continuing

Nitric oxide (NO) is produced from virtually all cell types composing the myocardium and regulates cardiac function through both vascular-dependent and -independent effects. The former include regulation of coronary vessel tone, thrombogenicity, and proliferative and inflammatory properties as well as cellular cross-talk supporting angiogenesis. The latter comprise the direct effects of NO on several aspects of cardiomyocyte contractility, from the fine regulation of excitation-contraction coupling to modulation of (presynaptic and postsynaptic) autonomic signaling and mitochondrial respiration. This multifaceted involvement of NO in cardiac physiology is supported by a tight molecular regulation of the three NO synthases, from cellular spatial confinement to posttranslational allosteric modulation by specific interacting proteins, acting in concert to restrict the influence of NO to a particular intracellular target in a stimulus-specific manner. Loss of this specificity, such as produced on excessive NO delivery from inflammatory cells (or cytokine-stimulated cardiomyocytes themselves), may result in profound cellular disturbances leading to heart failure. Future therapeutic manipulations of cardiac NO synthesis will necessarily draw on additional characterization of the cellular and molecular determinants for the net effect of this versatile radical on the cardiomyocyte biology.

Determination of nitrite plus nitrate and malondialdehyde in human plasma: analytical performance and the effect of smoking and exercise

The aim of this study was to evaluate the analytical performance and clinical usefulness of spectrophotometric assays for the measurement of the plasma levels of nitrite plus nitrate (NOx), and malondialdehyde (MDA), as an index of nitric oxide release and lipid peroxidation, respectively. We studied 30 healthy sedentary volunteers, 12 endurance athletes and 12 regular heavy smokers. The lower limit of quantification for plasma NOx concentration was 1 micromol/l, and linearity was observed from 1 to 40 micromol/l of NOx concentration. Variation in replicate samples within or between days was always below 5%. NOx levels were significantly higher in athletes compared to both control subjects and smokers (p<0.05 and p<0.001, respectively), as well as in healthy subjects compared to smokers (p<0.05). The analytical limit of quantification for plasma MDA concentration was 0.03 micromol/l, and linearity was observed from 0.03 to 20 micromol/l of MDA concentration. Variation in replicate samples within or between runs was <5%. Mean MDA concentration was significantly higher in smokers compared to control subjects and athletes (p<0.001). A significant inverse relationship (p<0.001) was observed when comparing NOx with MDA (r=-0.49) or LDL levels (r=-0.30) in the total population. The assays evaluated in this study proved to be sensitive, specific and practicable, and therefore suitable for routine application in clinical chemistry laboratories and/or physiopathological studies involving human blood samples.