scholarly journals Modulatory Effects of L-Arginine on Methylxanthine-Induced Cardiotoxicity in Rats: A Differential Role for Nitric Oxide (NO)

Author(s):  
Arunabha Ray ◽  
Md Shamsuzzaman ◽  
Jagdish C. Joshi ◽  
Kavita Gulati ◽  
Arunabha Ray

Methylxanthines are potent bronchodilators used in obstructive airway disease like COPD and bronchial asthma, but the narrow therapeutic index and resultant adverse effect profile have restricted their use. Novel beneficial effects and modes of action are now being proposed for these pharmacoeconomically viable agents. Cardiotoxicity is a prominent adverse effect of methylxanthone and thus we investigated possible mechanisms for such toxicity with an aim to devise ameliorative strategies for counteracting such undesirable effects. In view of the cardioprotective role of nitric oxide (NO) and NO mimetics, the present study investigated the possible modulatory role of L-arginine, a NO precursor, in theophylline induced cardiotoxicity in rats, with a view to exploring strategies for facilitating the safe use of this drug. The methylxanthine, aminophylline induced cardiotoxic effects like increased heart rat, raised mean BP, inverted T-waves and prolonged QTc interval (in ECG). These were accompanied by increased levels of cardiac biomarkers like Troponin-I, CPK-MB, and ADMA. Oxidative stress markers like MDA were elevated whereas, antioxidant defence markers like GSH and SOD were suppressed. Co-administration of L-arginine (with aminophylline) had dose-related effects on cardiac function (heart rate, mean BP, ECG changes) and cardiospecific biomarkers (TnI, CPK-MB, ADMA) - the lower dose being protective whereas the higher dose potentiating some of the cardiac effects and cardiospecific/oxidative stress biomarker levels. The results indicate a biphasic involvement of NO in the cardiotoxic effect of theophylline and suggests possible interactions of NO with reactive oxygen species during such modulations of cardiotoxicity.

Antioxidants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1002
Author(s):  
Fabiola Marino ◽  
Mariangela Scalise ◽  
Eleonora Cianflone ◽  
Luca Salerno ◽  
Donato Cappetta ◽  
...  

Over the years strong evidence has been accumulated showing that aerobic physical exercise exerts beneficial effects on the prevention and reduction of cardiovascular risk. Exercise in healthy subjects fosters physiological remodeling of the adult heart. Concurrently, physical training can significantly slow-down or even reverse the maladaptive pathologic cardiac remodeling in cardiac diseases, improving heart function. The underlying cellular and molecular mechanisms of the beneficial effects of physical exercise on the heart are still a subject of intensive study. Aerobic activity increases cardiovascular nitric oxide (NO) released mainly through nitric oxidase synthase 3 activity, promoting endothelium-dependent vasodilation, reducing vascular resistance, and lowering blood pressure. On the reverse, an imbalance between increasing free radical production and decreased NO generation characterizes pathologic remodeling, which has been termed the “nitroso-redox imbalance”. Besides these classical evidence on the role of NO in cardiac physiology and pathology, accumulating data show that NO regulate different aspects of stem cell biology, including survival, proliferation, migration, differentiation, and secretion of pro-regenerative factors. Concurrently, it has been shown that physical exercise generates physiological remodeling while antagonizes pathologic remodeling also by fostering cardiac regeneration, including new cardiomyocyte formation. This review is therefore focused on the possible link between physical exercise, NO, and stem cell biology in the cardiac regenerative/reparative response to physiological or pathological load. Cellular and molecular mechanisms that generate an exercise-induced cardioprotective phenotype are discussed in regards with myocardial repair and regeneration. Aerobic training can benefit cells implicated in cardiovascular homeostasis and response to damage by NO-mediated pathways that protect stem cells in the hostile environment, enhance their activation and differentiation and, in turn, translate to more efficient myocardial tissue regeneration. Moreover, stem cell preconditioning by and/or local potentiation of NO signaling can be envisioned as promising approaches to improve the post-transplantation stem cell survival and the efficacy of cardiac stem cell therapy.


Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 160
Author(s):  
Vladana Domazetovic ◽  
Irene Falsetti ◽  
Caterina Viglianisi ◽  
Kristian Vasa ◽  
Cinzia Aurilia ◽  
...  

Vitamin E, a fat-soluble compound, possesses both antioxidant and non-antioxidant properties. In this study we evaluated, in intestinal HT29 cells, the role of natural tocopherols, α-Toc and δ-Toc, and two semi-synthetic derivatives, namely bis-δ-Toc sulfide (δ-Toc)2S and bis-δ-Toc disulfide (δ-Toc)2S2, on TNFα-induced oxidative stress, and intercellular adhesion molecule-1 (ICAM-1) and claudin-2 (Cl-2) expression. The role of tocopherols was compared to that of N-acetylcysteine (NAC), an antioxidant precursor of glutathione synthesis. The results show that all tocopherol containing derivatives used, prevented TNFα-induced oxidative stress and the increase of ICAM-1 and Cl-2 expression, and that (δ-Toc)2S and (δ-Toc)2S2 are more effective than δ-Toc and α-Toc. The beneficial effects demonstrated were due to tocopherol antioxidant properties, but suppression of TNFα-induced Cl-2 expression seems not only to be related with antioxidant ability. Indeed, while ICAM-1 expression is strongly related to the intracellular redox state, Cl-2 expression is TNFα-up-regulated by both redox and non-redox dependent mechanisms. Since ICAM-1 and Cl-2 increase intestinal bowel diseases, and cause excessive recruitment of immune cells and alteration of the intestinal barrier, natural and, above all, semi-synthetic tocopherols may have a potential role as a therapeutic support against intestinal chronic inflammation, in which TNFα represents an important proinflammatory mediator.


2010 ◽  
Vol 63 (11-12) ◽  
pp. 827-832 ◽  
Author(s):  
Tatjana Radosavljevic ◽  
Dusan Mladenovic ◽  
Danijela Vucevic ◽  
Rada Jesic-Vukicevic

Introduction. Paracetamol is an effective analgesic/antipyretic drug when used at therapeutic doses. However, the overdose of paracetamol can cause severe liver injury and liver necrosis. The mechanism of paracetamol-induced liver injury is still not completely understood. Reactive metabolite formation, depletion of glutathione and alkylation of proteins are the triggers of inhibition of mitochondrial respiration, adenosine triphosphate depletion and mitochondrial oxidant stress leading to hepatocellular necrosis. Role of oxidative stress in paracetamol-induced liver injury. The importance of oxidative stress in paracetamol hepatotoxicity is controversial. Paracetamol induced liver injury cause the formation of reactive oxygen species. The potent sources of reactive oxygen are mitochondria, neutrophils, Kupffer cells and the enzyme xatnine oxidase. Free radicals lead to lipid peroxidation, enzymatic inactivation and protein oxidation. Role of mitochondria in paracetamol-induced oxidative stress. The production of mitochondrial reactive oxygen species is increased, and the glutathione content is decreased in paracetamol overdose. Oxidative stress in mitochondria leads to mito?chondrial dysfunction with adenosine triphosphate depletion, increase mitochondrial permeability transition, deoxyribonu?cleic acid fragmentation which contribute to the development of hepatocellular necrosis in the liver after paracetamol overdose. Role of Kupffer cells in paracetamol-induced liver injury. Paracetamol activates Kupffer cells, which then release numerous cytokines and signalling molecules, including nitric oxide and superoxide. Kupffer cells are important in peroxynitrite formation. On the other hand, the activated Kupffer cells release anti-inflammatory cytokines. Role of neutrophils in paracetamol-induced liver injury. Paracetamol-induced liver injury leads to the accumulation of neutrophils, which release lysosomal enzymes and generate superoxide anion radicals through the enzyme nicotinamide adenine dinucleotide phosphate oxidase. Hydrogen peroxide, which is influenced by the neutrophil-derived enzyme myeloperoxidase, generates hypochlorus acid as a potent oxidant. Role of peroxynitrite in paracetamol-induced oxidative stress. Superoxide can react with nitric oxide to form peroxynitrite, as a potent oxidant. Nitrotyrosine is formed by the reaction of tyrosine with peroxynitrite in paracetamol hepatotoxicity. Conclusion. Overdose of paracetamol may produce severe liver injury with hepatocellular necrosis. The most important mechanisms of cell injury are metabolic activation of paracetamol, glutathione depletion, alkylation of proteins, especially mitochondrial proteins, and formation of reactive oxygen/nitrogen species.


1997 ◽  
Vol 19 (9-10) ◽  
pp. 599-605 ◽  
Author(s):  
H. Farghali ◽  
S. Hynie ◽  
Z. Vohnikova ◽  
K. Masek

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Yanti Octavia ◽  
Elza v Deel ◽  
Monique d Waard ◽  
Martine d Boer ◽  
An Moens ◽  
...  

AIMS: Beneficial effects of aerobic exercise training are widely recognized. However, previously we discovered that the positive effects of exercise depend on the underlying cause of cardiac failure. Here we tested the hypothesis that endothelial nitric oxide synthase (eNOS) dependent regulation of the balance between nitric oxide and superoxide (O2•-) is critically involved in determining the effects of exercise. METHODS: Mice were exposed to 8 weeks of voluntary wheel running exercise training (EX) or sedentary housing (SED) immediately following myocardial infarction (MI), pressure overload from a transverse aortic constriction (TAC), or sham (SH) surgery. Subsequently, left ventricular (LV) ejection fraction (EF) was measured by echocardiography and Picrosirius Red staining was performed to measure collagen content. Additionally, total and NOS-dependent LV O2•- were measured using lucigenin-enhanced chemiluminescence without or with NOS inhibitor, L-NAME. eNOS uncoupling was evaluated by determining eNOS monomer dimer protein ratio and peroxynitrite (ONOO-) levels were measured through luminol-enhanced chemiluminescence. RESULTS: Cardiac dysfunction and fibrosis were ameliorated by exercise in MI but not in TAC mice (Table 1). MI and TAC both increased LV O2•- levels. Strikingly, EX diminished O2•- generation in MI, but exacerbated O2•- generation in TAC (Table 1). Furthermore, the EX-induced increase in O2•- levels in TAC were largely NOS-dependent. Accordingly, MI and TAC-induced eNOS uncoupling was normalized by EX in MI but aggravated in TAC mice (Table 1). Similarly, increased ONOO- levels following MI and TAC were diminished by EX in MI, but exacerbated by EX in TAC (Table 1). CONCLUSIONS: EX reduces eNOS-mediated cardiac oxidative stress in MI. In contrast, beneficial effects of EX are lacking in cardiac pressure-overload following TAC, due to EX-induced aggravation of ONOO- formation, eNOS uncoupling and concomitant oxidative stress.


Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Ghulam Akbar ◽  
Marwan Badri ◽  
Catherine Prince ◽  
Wajeeha Saeed ◽  
Ghazi Mirrani ◽  
...  

Introduction: Takostubo cardiomyopathy (TK) and STEMI in the proximal to mid LAD territory (LAD-S) may have similar clinical, ECG and echocardiographic presentation. The two can only be differentiated using coronary angiography. Hypothesis: We hypothesized that the ratio of serum BNP to troponin-I(TnI) will help in distinguishing TK from LAD-S. Previously it has been studied in TK and STEMI from any coronary artery lesion. This is the first study to tease out LAD-S and TK by using BNP/TnI ratio . Methods: We retrospectively compared patients who presented with LAD-S and patients with TK (confirmed with non-obstructive coronary angiography, classic echocardiographic appearance and subsequent improvement of LV function). Patients who did not have BNP and TnI available were excluded. Results: Out of 313 patients with LAD-S and 464 with possible TK, 39 and 62 patients were included respectively. Mean BNP and TnI levels were 788, 57.6ng/dl and 923, 3.4ng/dl in LAD-S and TK respectively. A BNP/TnI ratio of ≤6.4 was 100% sensitive and 41% specific to diagnose LAD-S, and therefore has 100% negative predictive value. A BNP/TnI ratio of ≥2388 was 80% sensitive and 93% specific for diagnosing TK. Conclusion: BNP/TnI ratio <6.4 is reliable to rule out TK and lead to the diagnosis of LAD-S in patients with typical echocardiographic findings. Further, larger observational studies are needed to validate the use of biomarkers for this purpose.


2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Ketab E. Al-Otaibi ◽  
Abdulrahman M. Al Elaiwi ◽  
Mohammad Tariq ◽  
Abdulrahman K. Al-Asmari

Contrast media- (CM-) induced nephropathy is a serious complication of radiodiagnostic procedures. Available data suggests that the development of prophylaxis strategies is limited by poor understanding of pathophysiology of CM-induced nephropathy. Present study was designed to determine the role of oxidative stress, myeloperoxidase, and nitric oxide in the pathogenesis of iohexol model of nephropathy and its modification with simvastatin (SSTN). Adult Sprague Dawley rats were divided into seven groups. After 24 h of water deprivation, all the rats except in control and SSTN-only groups were injected (10 ml/kg) with 25% glycerol. After 30 min, SSTN (15, 30, and 60 mg/kg) was administered orally, daily for 4 days. Twenty-four hours after the glycerol injection, iohexol was infused (8 ml/kg) through femoral vein over a period of 2 min. All the animals were sacrificed on day 5 and blood and kidneys were collected for biochemical and histological studies. The results showed that SSTN dose dependently attenuated CM-induced rise of creatinine, urea, and structural abnormalities suggesting its nephroprotective effect. A significant increase in oxidative stress (increased lipid hydroperoxides and reduced glutathione levels) and myeloperoxidase (MPO) and decreased nitric oxide in CM group were reversed by SSTN. These findings support the use of SSTN to combat CM-induced nephrotoxicity.


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