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Publications (43)
Light pollution disturbs circadian rhythm, and this can also be deleterious to the heart by increased susceptibility to arrhythmias. Herein, we investigated if rats exposed to continuous light had altered myocardial gene transcripts and/or protein expression which affects arrhythmogenesis. We then assessed if Omacor® supplementation benefitted affe...
Cardiac β-adrenergic overstimulation results in oxidative stress, hypertrophy, ischemia, lesion, and fibrosis rendering the heart vulnerable to malignant arrhythmias. We aimed to explore the anti-arrhythmic efficacy of the anti-oxidative and anti-inflammatory compounds, melatonin, and omega-3, and their mechanisms of actions in normotensive and hyp...
Irradiation of normal tissues leads to acute increase in reactive oxygen/nitrogen species that serve as intra and intercellular signaling to alter cell and tissue function. In the case of chest irradiation it can affect the heart, blood vessels and lungs, with consequent tissue remodelation and adverse side effects and symptoms. This complex proces...
We aimed to explore whether myocardial intercellular channel protein connexin-43 (Cx43) along with PKCε and MMP-2 might be implicated in responses to acute cardiac injury induced by two distinct sub-lethal interventions in Wistar rats. Animals underwent either single chest irradiation at dose of 25 Gy or subcutaneous injection of isoproterenol (ISO...
We aimed to study the impact of altered thyroid status on myocardial expression of electrical coupling protein connexin-43 (Cx43), the susceptibility of rats to ventricular fibrillation (VF) and the effects of antioxidant-rich red palm oil (RPO). Adult male and female euthyroid, hyperthyroid (treated with T3/T4), hypothyroid (treated with methimazo...
Mechanisms underlying atrial fibrillation (AF), the most common
cardiac arrhythmia, particularly in aged population, are not fully
elucidated. We have previously shown an increased propensity of
old guinea pigs (GPs) heart to inducible AF when comparing to
young animals. This study aimed to verify our hypothesis that
susceptibility of aged heart to...
We aimed to explore the effects of melatonin and n-3 polyunsaturated fatty acids (PUFA) supplementation on plasma and aortic nitric oxide (NO) levels in isoproterenol (Iso) affected spontaneously hypertensive (SHR) and Wistar rats. Untreated control rats were compared with Iso injected (118 mg/kg, s.c.) rats, and Iso injected plus supplemented with...
Thyroid hormones are powerful modulators of heart function and susceptibility to arrhythmias via both genomic and non-genomic actions. We aimed to explore expression of electrical coupling protein connexin-43 (Cx43) in the heart of rats with altered thyroid status and impact of omega-3 polyunsaturated fatty acids (omega-3) supplementation. Adult ma...
We aimed to determine the impact of Ca(2+)-related disorders induced in intact animal hearts on ultrastructure of the cardiomyocytes prior to occurrence of severe arrhythmias. Three types of acute experiments were performed that are known to be accompanied by disturbances in Ca(2+) handling. Langedorff-perfused rat or guinea pig hearts subjected to...
Gap junction connexin channels are important determinants of myocardial conduction and synchronization that is crucial for coordinated heart function. One of the main risk factors for cardiovascular events that results in heart attack, congestive heart failure, stroke as well as sudden arrhythmic death is hypertension. Mislocalization and/or dysfun...
Excessive production of oxygen free radicals has been regarded as a causative common denominator of many pathological processes in the animal kingdom. Hydroxyl and nitrosyl radicals represent the major cause of the destruction of biomolecules either by a direct reaction or by triggering a chain reaction of free radicals. Scavenging of free radicals...
Gap-junction connexin (Cx) channels are important determinants of myocardial conduction and synchronization that is crucial for heart function. Hypertension-induced structural remodeling is associated with an increased risk of life-threatening arrhythmias and heart failure in both humans and experimental animals. Recent studies suggest that abnorma...
Intercellular connexin-43 (Cx43) channels are essential for electrical coupling and direct cardiac cell to cell communication to ensure heart function. Expression of Cx43 is altered due to stressful conditions and also affected by the alterations in extracellular matrix. We aimed to explore the effect of chest irradiation on myocardial expression o...
Objectives: Cardioprotective compounds, atorvastatin, melatonin, eicosapentaenoic (EPA) and docosahexaenoic acid (DPA) show antiarrhythmic effects in clinical as well as in experimental studies, but their acute effects are less examined. The aim of the study was to further our understanding of the effects of monitored antiarrhythmic agents and thei...
This review deals with the understanding of the role of key factors of ageing, oxidative stress and inflammation, in relation to development of age-related cardiovascular disease, atrial fibrillation. Increased production of reactive oxygen species and systemic inflammation promote cardiac structural and electrophysiologic remodeling that is crucia...
Previous data suggest that type-1 diabetes mellitus leads to the deterioration of myocardial intercellular communication mediated by connexin-43 (Cx43) channels. We therefore aimed to explore Cx43, PKC signaling and ultrastructure in non-treated and omega-3 fatty acid (omega-3) treated spontaneously diabetic Goto-Kakizaki (GK) rats considered as ty...
Rationale: Hypokalemia is the most common electrolyte abnormality encountered in clinical practice and enhances the propensity for ventricular fibrillation (VF). Melatonin upregulates the gap junction channels protein, connexin43 (Cx43), rendering the heart more resistant to electricallyinduced VF. We hypothesized that melatonin may protect agai...
Objective: Sustained beta-adrenoceptor activation is deleterious to the heart due to induction of pathological remodeling and compromising cardiomyocytes viability that increase a risk for sudden cardiac death. Our and others studies suggest that melatonin and omega-3 fatty acids are cardioprotective but underlying mechanisms are not fully elucidat...
Melatonin prevents alterations in the gap junction channels formed by connexin-43 (Cx43) rendering the heart more resistant to electricallyinduced ventricular fibrillation (VF) but its properties in others arrhythmogenic scenarios like hypokalemia remain unknouwn. We hypothesized that melatonin may protect against low potassium induced VF in part b...
Defects in intercellular coupling in the heart play a key role in the initiation and persistence of malignant arrhythmias. Such disorders result from abnormal expression and distribution of connexins, the major constituents of cardiac gap junction channels. The alterations of myocardial connexin are well established as a consistent feature of both...
Cardioprotective compounds such as atorvastatin, melatonin, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) exhibit antiarrhythmic potential in clinical and/or experimental conditions but underlying mechanisms are poorly understood. We have previously shown that protection from ventricular fibrillation (VF) due to prolonged treatment wit...
Objectives: It is very well known from experimental as well as clinical studies that the pineal hormone, melatonin, which regulates circadian rhythms, exhibits cardioprotective effects.The goal of the study was to confirm our hypothesis and to explore the antiarrhythmic effects of the supplementation of melatonin in hypertensive and normotensive ra...
Objectives: Myocardial synchronization and proper heart function depends on the expression and subcellular distribution of intercellular connexin-43 (Cx43) channels that are essential for electrical coupling and direct cell-to-cell communication. Radiotherapy is applied to treat cancer but chest irradiation can induce heart disease. We hypothesized...
One of the most widely used methods of treating oncological patients is ionizing radiation therapy. Radiation beam causes damage to the cancer cells which can reduce cancerous mass and leads to recovery of the oncological patients. On the other hand irradiation of other nearby tissues like myocardium can cause some damage which can induce serious h...
Background and purpose: The cardiovascular system is modulated by thyroid hormones and their deficiency or excess in hypo- (HY) or hyperthyroid (TH) status may affect both cardiac function and arrhythmogenesis. We hypothesized that intercellular communication via connexin-43 (Cx43) channels might be implicated. The goal of this study was to explore...
Background: Hypertension remains the most prevalent risk factor that increases propensity of the heart to the malignant arrhythmias due to myocardial remodeling. Data, including ours, suggest that hypertension is accompanied by melatonin and omega-3 FA deficiency but enhanced free radicals production. In turn, high BP was reduced in pts and/or anim...
Background and Purpose: Melatonin in addition to regulation of circadian rhythm exhibits antihypertensive, free radicals scavenging and antiarrhythmic effects as we have shown recently. While melatonin deficiency and lower omega-3 index observed in pts suffering from CHD and hypertension as well as in SHR can contribute to disease progression and p...
This study was designed to examine in vivo functional changes of the heart in the early stages of streptozotocin (STZ)-induced diabetic cardiomyopathy and to evaluate the effects of n-3 PUFA intake. Moreover, we investigated whether modulation of diabetes-related abnormalities of myocardial connexin-43 (Cx43), β-myosin heavy chain (β-MHC), and β1-a...
We hypothesized that the pineal hormone melatonin, which exhibits cardioprotective effects, might affect myocardial expression of cell-to-cell electrical coupling protein connexin-43 (Cx43) and protein kinase C (PKC) signaling, and hence, the propensity of the heart to lethal ventricular fibrillation (VF). Spontaneously hypertensive (SHR) and normo...
Rationale and Purpose: Mechanisms underlying atrial fibrillation (AF) the most common cardiac arrhythmia in aged population are not fully elucidated. We have previously shown that unlike to young the aged guinea pig heart is much prone to develop AF upon repetitive burst stimulation. We hypothesize that in addition to atrial structural remodeling t...
The purpose of this study was to test our hypothesis that red palm oil (RPO) intake may affect abnormalities of myocardial connexin-43 (Cx43) and protein kinase Cε (PKCε) signaling, and consequently the propensity of the spontaneously hypertensive rat heart (SHR) heart to arrhythmias. SHR and Wistar-Kyoto (WKY) rats fed a standard rat chow plus red...
Cardiac connexin-43 (C×43) channels at the gap junctions play a crucial role in synchronizing the myocardium, allowing electrical and molecular signals propagation amongst cardiomyocytes. Previously we have shown that up-regulation of C×43 is most likely involved in the antiarrhythmic mechanisms of omega-3 fatty acids. The aim of this study was to...
