(20-06-13) Dietary omega-3 fatty acids attenuate myocardial arrhythmogenic factors and propensity of the heart to lethal arrhythmias

Dietary omega-3 fatty acids attenuate myocardial arrhythmogenic factors and propensity of the heart to lethal arrhythmias in a rodent model of human essential hypertension.

Radosinska J, Bacova B, Knezl V, Benova T, Zurmanova J, Soukup T, Arnostova P, Slezak J, Gonçalvesova E, Tribulova N.
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aInstitute for Heart Research, Slovak Academy of Sciences bFaculty of Medicine, Institute of Physiology, Comenius University cInstitute of Experimental Pharmacology and Toxicology, Slovak Academy of Sciences, Bratislava, Slovakia dFaculty of Science, Department of Physiology, Charles University eInstitute of Physiology, v.v.i., Academy of Sciences of Czech Republic, Prague, Czech Republic fThe National Cardiovascular Institute, Bratislava, Slovakia *Jana Radosinska and Barbara Bacova contributed equally to the writing of the article.
Abstract
OBJECTIVE:: Hypertension-induced myocardial remodeling is known to be associated with increased risk for malignant arrhythmias and alterations in electrical coupling protein, connexin-43 (Cx43), may be involved. We investigated whetheromega-3 fatty acids intake affects abnormalities of Cx43 as well as protein kinase C (PKC) signaling and myosin heavy chain (MyHC) profile at the early and late stage of hypertension in the context of the heart's susceptibility to ventricular fibrillation and ability to restore sinus rhythm. METHODS:: Untreated young and old male spontaneously hypertensive rats (SHRs) and age-matched normotensive rats were compared with animals supplemented by omega-3 (eicosapentaneoic acid + docosahexaneoic acid, 200 mg/kg body weight/day) for 2 months. Left ventricular tissues were taken for examination of subcellular integrity of gap junctions, Cx43 mRNA and protein expression, PKCε and PKCδ as well as MyHC determination. Electrically inducible ventricular fibrillation and sinus rhythm restoration (SRR) were examined on Langedorff-perfused heart preparation. RESULTS:: Omega-3 intake significantly reduced cardiovascular risk factors, suppressed inducible ventricular fibrillation, and facilitated SRR in hypertensive rats. Supplementation attenuated lateralization and internalization of Cx43, suppressed elevated Cx43 mRNA, enhanced total Cx43 protein expression and/or expression of its functional phosphorylated forms as well as the expression of cardioprotective PKC-ε and suppressed pro-apoptotic PKC-δ isoform. Moreover, the omega-3 diet normalized MyHC profiles in SHR at early stage of disease and old nonhypertensive rats, but failed to do so in old SHR at late stage of disease. CONCLUSION:: Findings suggest that amelioration of myocardial Cx43-related abnormalities, positive modulation of PKC pathways, and normalization of MyHC can significantly contribute to the antiarrhythmic effects of omega-3 in rat model mimicking human essential hypertension. Our results support the prophylactic use of omega-3 to minimize cardiovascular risk and sudden arrhythmic death.

Source: J Hypertens. 2013 May 28. [Epub ahead of print]

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