Activation of inducible NOS in peripheral vessels and outcomes in heart failure patients

Association of serum nitric oxide metabolite level with mortality in patients undergoing coronary angiography

BACKGROUND

Nitric oxide (NO) is a relevant molecule for vascular homeostasis. The level of serum NO metabolites (NOx), which consist of nitrite and nitrate, has been investigated as an alternative biomarker of NO production, but its clinical value has not yet been determined.

METHODS AND RESULTS

143 patients (66 ± 12 years old) were followed up after coronary catheterization. During a median (inter-quartile range) observation period of 6.13 (3.32-9.21) years, there were 20 (14 %) all-cause deaths, including 11 (8 %) cardiovascular deaths, 17 (12 %) major adverse cardiovascular events, and 17 (12 %) hospital admissions for heart failure. Median NOx level was 34.5 μmol/L (23.9-54.3). NOx was a risk factor for all-cause death [hazard ratio (HR) by unit increase, 1.010, 95 % confidence interval (CI) 1.001-1.018; p = 0.021] and heart failure (HR 1.010, CI 1.001-1.019; p = 0.029). Even after adjustment for age, sex, coronary risk factors, C-reactive protein, log-transformed brain natriuretic peptide, estimated glomerular filtration rate, and nitrate treatment, NOx was a risk factor for all-cause death (HR 1.015, CI 1.004-1.027; p = 0.008) and admission with heart failure (HR 1.018, CI 1.005-1.018, p = 0.007).

CONCLUSIONS

An increase in serum NOx level does not herald a benign clinical course but is an independent predictor of high risk of any-cause mortality and heart failure.

Bacopa monniera extract mitigates isoproterenol-induced cardiac stress via Nrf2/Keap1/NQO1 mediated pathway

The present study was aimed to investigate the effect of standardised hydroalcoholic extract of Bacopa monniera (BME) against isoproterenol (ISO) induced cardiac stress. Isoproterenol (85 mg/kg body weight) was administered intraperitoneally to induce cardiac stress in rats. Bacopa monniera extract (BME75 and 150 mg/kg) was orally administered for 21 days followed by ISO on 22nd and 23rd experimental days. ISO caused significant cardiac damage, which was concomitant with increased apoptosis and attenuated expressions of Nrf2, HO-1, and regulating apoptotic protein expressions of Bax, Bcl2 and NOS2. Treatment with BME in rats significantly improved cardiac dysfunction by maintaining cardiac rhythm, myocardial integrity. Decreased oxidative stress by restored expressions of Nrf2, NQO1 and HO-1 followed by elevating antioxidant enzymes and total glutathione levels. Our present results suggest that the BME treatment strengthening the endogenous defence system through Nrf2 modulation and played a key role against cardiac oxidative stress induced by ISO in rats.

Inflammation in Human Heart Failure: Major Mediators and Therapeutic Targets

Inflammation has been recognized as a major pathophysiological contributor to the entire spectrum of human heart failure (HF), including HF with reduced ejection fraction, HF with preserved ejection fraction, acute HF and cardiogenic shock. Nevertheless, the results of several trials attempting anti-inflammatory strategies in HF patients have not been consistent or motivating and the clinical implementation of anti-inflammatory treatments for HF still requires larger and longer trials, as well as novel and/or more specific drugs. The present work reviews the different inflammatory mechanisms contributing to each type of HF, the major inflammatory mediators involved, namely tumor necrosis factor alpha, the interleukins 1, 6, 8, 10, 18, and 33, C-reactive protein and the enzymes myeloperoxidase and inducible nitric oxide synthase, and their effects on heart function. Furthermore, several trials targeting these mediators or involving other anti-inflammatory treatments in human HF are also described and analyzed. Future therapeutic advances will likely involve tailored anti-inflammatory treatments according to the patient's inflammatory profile, as well as the development of resolution pharmacology aimed at stimulating resolution of inflammation pathways in HF.

Role of non-coding RNAs in cardiotoxicity of chemotherapy

The long-time paradoxical situation of non-coding RNAs (ncRNAs) has been terminated for they emerge as executive at full spectrum of gene expression and translation. More recently, it has been demonstrated that some ncRNAs apparently are associated with chemotherapy, causing cardiotoxicity, which taint long-term recovery of patients in growing body of evidence. The current review focused on up-to-date knowledge on regulation change and molecular signaling of ncRNAs, at mean time evaluate their potentials as diagnostic biomarkers or therapeutic targets to monitor and protect cardio function.

Cardioprotective mechanisms of phytochemicals against doxorubicin-induced cardiotoxicity

Doxorubicin (DOX) is an anthracycline antibiotic, which is effectively used in the treatment of different malignancies, such as leukemias and lymphomas. Its most serious side effect is dose-dependent cardiotoxicity, which occurs through inducing oxidative stress apoptosis. Due to the myelosuppressive effect of dexrazoxane, a commonly-used drug to alleviate DOX-induced cardiotoxicity, researchers investigated the potential of phytochemicals for prophylaxis and treatment of this condition. Phytochemicals are plant chemicals that have protective or disease preventive properties. Preclinical trials have shown antioxidant properties for several plant extracts, such as those of Aerva lanata, Aronia melanocarpa, Astragalus polysaccharide, and Bombyx mori plants. Other plant extracts showed an ability to inhibit apoptosis, such as those of Astragalus polysaccharide, Azadirachta indica, Bombyx mori, and Allium stavium plants. Unlike synthetic agents, phytochemicals do not impair the clinical activity of DOX and they are particularly safe for long-term use. In this review, we summarized the results of preclinical trials that investigated the cardioprotective effects of phytochemicals against DOX-induced cardiotoxicity. Future human trials are required to translate these cardioprotective mechanisms into practical clinical implications.

Cardioprotective and hepatoprotective effects of Citrus hystrix peels extract on rats model

OBJECTIVE

To observe the combination effect of doxorubicin and Citrus hystrix (kaffir lime's) peel ethanolic extract (ChEE) on blood serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity and cardio-hepato-histopathology of female Sprague Dawley rats.

METHODS

Doxorubicin and ChEE (5 rats per group) were administered in five groups of 3 rats each for 11 d. Group I: doxorubicin (dox) 4.67 mg/kg body weight; Group II: dox+ChEE 500 mg/kg body weight; Group III: dox+ChEE 1 000 mg/kg body weight; Group IV: ChEE 1 000 mg/kg body weight; Group V: untreated (control).

RESULTS

ChEE repaired cardiohistopathology profile of doxorubicin induced cardiotoxicity and hepatotoxicity rats, but did not repair neither hepatohistopathology profile nor reduce serum activity of ALT and AST.

CONCLUSION

ChEE has potency to be developed as cardioprotector agent in chemotherapy.

Ginkgo biloba extract individually inhibits JNK activation and induces c-Jun degradation in human chondrocytes: potential therapeutics for osteoarthritis

Osteoarthritis (OA) is a common joint disorder with varying degrees of inflammation. The ideal anti-OA drug should have immunomodulatory effects while at the same time having limited or no toxicity. We examined the anti-inflammatory effects of Ginkgo biloba extract (EGb) in interleukin-1 (IL-1)-stimulated human chondrocytes. Chondrocytes were prepared from cartilage specimens taken from patients with osteoarthritis who had received total hip or total knee replacement. The concentrations of chemokines and the degree of cell migration were determined by ELISA and chemotaxis assays, respectively. The activation of inducible nitric oxide synthase (iNOS), mitogen-activated protein kinases (MAPKs), activator protein-1 (AP-1), and nuclear factor-kappaB (NF-κB) was determined by immunoblotting, immunohistochemistry, and electrophoretic mobility shift assay. We found that EGb inhibited IL-1-induced production of chemokines, which in turn resulted in attenuation of THP-1 cell migration toward EGb-treated cell culture medium. EGb also suppressed IL-1-stimulated iNOS expression and release of nitric oxide (NO). The EGb-mediated suppression of the iNOS-NO pathway correlated with the attenuation of activator protein-1 (AP-1) but not nuclear factor-kappaB (NF-κB) DNA-binding activity. Of the mitogen-activated protein kinases (MAPKs), EGb inhibited only c-Jun N-terminal kinase (JNK). Unexpectedly, EGb selectively caused degradation of c-Jun protein. Further investigation revealed that EGb-mediated c-Jun degradation was preceded by ubiquitination of c-Jun and could be prevented by the proteosome inhibitor MG-132. The results imply that EGb protects against chondrocyte degeneration by inhibiting JNK activation and inducing ubiquitination-dependent c-Jun degradation. Although additional research is needed, our results suggest that EGb is a potential therapeutic agent for the treatment of OA.

Nitric oxide-mediated coronary flow regulation in patients with coronary artery disease: recent advances

Nitric oxide (NO) formed via endothelial NO synthase (eNOS) plays crucial roles in the regulation of coronary blood flow through vasodilatation and decreased vascular resistance, and in inhibition of platelet aggregation and adhesion, leading to the prevention of coronary circulatory failure, thrombosis, and atherosclerosis. Endothelial function is impaired by several pathogenic factors including smoking, chronic alcohol intake, hypercholesterolemia, obesity, hyperglycemia, and hypertension. The mechanisms underlying endothelial dysfunction include reduced NO synthase (NOS) expression and activity, decreased NO bioavailability, and increased production of oxygen radicals and endogenous NOS inhibitors. Atrial fibrillation appears to be a risk factor for endothelial dysfunction. Endothelial dysfunction is an important predictor of coronary artery disease (CAD) in humans. Penile erectile dysfunction, associated with impaired bioavailability of NO produced by eNOS and neuronal NOS, is also considered to be highly predictive of ischemic heart disease. There is evidence suggesting an important role of nitrergic innervation in coronary blood flow regulation. Prophylactic and therapeutic measures to eliminate pathogenic factors inducing endothelial and nitrergic nerve dysfunction would be quite important in preventing the genesis and development of CAD.

Ouabain increases iNOS-dependent nitric oxide generation which contributes to the hypertrophic effect of the glycoside: possible role of peroxynitrite formation

In addition to inotropic effects, cardiac glycosides exert deleterious effects on the heart which limit their use for cardiac therapeutics. In this study, we determined the possible contribution of ouabain-induced iNOS stimulation to the resultant hypertrophic as well as cytotoxic effects of the glycoside on cultured adult rat ventricular myocytes. Myocytes were treated with ouabain (50 μM) for up to 24 h. Ouabain significantly increased gene and protein levels of inducible nitric oxide synthase (iNOS) which was associated with significantly increased release of NO from myocytes as well as increased total release of reactive oxygen species (ROS), superoxide anion (O(2) (-)), and increased peroxynitrite formation as assessed by protein tyrosine nitration. Administration of ouabain was also associated with increased levels of myocyte toxicity as determined by myocyte morphology, trypan blue staining and lactate dehydrogenase (LDH) efflux. The nonspecific NOS inhibitor Nω-nitro-L: -arginine methyl ester and the more selective iNOS inhibitor 1400W both abrogated the increase in LDH release but had no significant effect on either morphology or trypan blue staining. Ouabain also significantly increased both myocyte surface area and expression of atrial natriuretic peptide indicating a hypertrophic response with both parameters being completely prevented by NOS inhibition. The effects of iNOS inhibitors were associated with diminished ouabain tyrosine nitration as well as abrogation of ouabain-induced p38 and ERK phosphorylation. Our study shows that ouabain is a potent inducer of NO formation, iNOS upregulation, and increased production of ROS. Inhibition of ouabain-dependent peroxynitrite formation may contribute to the antihypertrophic effect of iNOS inhibition possibly by preventing downstream MAPK activation.

Oxidative stress: a key contributor to diabetic cardiomyopathy

Diabetes and its associated complications are major known health disorders. Diabetes mellitus increases the risk of cardiovascular morbidity and mortality by promoting cardiomyopathy. It appears to arise as a result of the diabetic state, at times independent of vascular or valvular pathology. It manifests initially as asymptomatic diastolic dysfunction, which progresses to symptomatic heart failure. The compliance of the heart wall is decreased and contractile function is impaired. The pathophysiology of diabetic cardiomyopathy is incompletely understood but appears to be multifactorial in origin. Several hypotheses have been proposed, including oxidative stress, inflammation, endothelial dysfunction, metabolic derangements, abnormalities in ion homeostasis, alterations in structural proteins, and interstitial fibrosis. Amongst these various mechanisms, an increase in reactive oxygen species, leading to oxidative stress, has received significant experimental support. This review focuses on the role of oxidative stress in the pathogenesis of diabetic cardiomyopathy and the potential of antioxidant therapy.

CPU86017, a berberine derivative, attenuates cardiac failure through normalizing calcium leakage and downregulated phospholamban and exerting antioxidant activity

AIM

To investigate whether CPU86017, a berberine derivative, attenuates heart failure by blocking calcium influx and exerting its antioxidant activity.

METHODS

Myocardial infarction was induced in male Sprague-Dawley rats for 17 d followed by isoproterenol (ISO) (5 mg/kg, sc) treatment for 5 d to reduce cardiac function. The rats were divided into 5 groups: sham operation, myocardial infarction (MI), MI plus ISO, and co-treated (in mg/kg, po) with either propranolol (PRO, 10) or CPU86017 (80). Hemodynamic measurements were conducted, and measurements of the redox system, calcium handling proteins and endothelin (ET) system in vivo were done. Furthermore, calcium flux studies and PLB immunocytochemistry were conducted in vitro.

RESULTS

Compared to sham operation, HF was evident following MI and further worsened by ISO treatment. This occurred in parallel with downregulated mRNA and protein production of SERCA2a, PLB, and FKBP12.6, and was associated with upregulation of preproET-1, endothelin converting enzyme, and PKA mRNA production in the myocardium in vivo. Calcium leakage was induced by ISO treatment of isolated beating myocytes in vitro. These changes were attenuated by treatment with either PRO or CPU86017. PLB fluorescence in myocytes was downregulated by ISO treatment, and was relieved significantly by treatment with antioxidant aminoguanidine, ascorbic acid or CPU86017 in vitro.

CONCLUSION

HF, calcium leakage, downregulated PLB, FKBP12.6, SERCA2a production, and upregulated PKA were caused by ISO treatment, and were abolished by CPU86017 treatment. The beneficial effects of CPU86017 are attributable to its antioxidant and calcium influx blocking effects.