(Hypertension. 2008;51:540.)
© 2008 American Heart Association, Inc.
Original Articles Part 2 |
From the Medical Faculty of the Charité (R.F., R.D., S.F., F.H., A.G., I.S., U.B.Z., E.S., A.S., F.C.L., D.N.M.), Experimental and Clinical Research Center, Franz Volhard Clinic and HELIOS Klinikum Berlin-Buch, Berlin, Germany; Max-Delbrueck-Center for Molecular Medicine (F.Q., M.M., R.P., A.H., F.C.L., W-H.S., D.N.M.), Berlin-Buch, Germany; Medical School of Hannover (J-K.P.), Hannover, Germany.
Correspondence to Robert Fischer, Experimental and Clinical Research Center, Max-Delbrueck-Center, Lindenberger Weg 80, 13125 Berlin, Germany. E-mail robert.fischer{at}charite.de
We compared the effect n-3 polyunsaturated fatty acids (PUFAs) with direct renin inhibition on electrophysiological remodeling in angiotensin II–induced cardiac injury. We treated double-transgenic rats expressing the human renin and angiotensinogen genes (dTGRs) from week 4 to 7 with n-3 PUFA ethyl-esters (Omacor; 25-g/kg diet) or a direct renin inhibitor (aliskiren; 3 mg/kg per day). Sprague-Dawley rats were controls. We performed electrocardiographic, magnetocardiographic, and programmed electrical stimulation. Dietary n-3 PUFAs increased the cardiac content of eicosapentaenoic and docosahexaenoic acid. At week 7, mortality in dTGRs was 31%, whereas none of the n-3 PUFA- or aliskiren-treated dTGRs died. Systolic blood pressure was modestly reduced in n-3 PUFA-treated (180±3 mm Hg) compared with dTGRs (208±5 mm Hg). Aliskiren-treated dTGRs and Sprague-Dawley rats were normotensive (110±3 and 119±6 mm Hg, respectively). Both n-3 PUFA–treated and untreated dTGRs showed cardiac hypertrophy and increased atrial natriuretic peptide levels. Prolonged QRS and QTc intervals and increased T-wave dispersion in dTGRs were reduced by n-3 PUFAs or aliskiren. Both treatments reduced arrhythmia induction from 75% in dTGRs to 17% versus 0% in Sprague-Dawley rats. Macrophage infiltration and fibrosis were reduced by n-3 PUFAs and aliskiren. Connexin 43, a mediator of intermyocyte conduction, was redistributed to the lateral cell membranes in dTGRs. n-3 PUFAs and aliskiren restored normal localization to the intercalated disks. Thus, n-3 PUFAs and aliskiren improved electrical remodeling, arrhythmia induction, and connexin 43 expression, despite a 70-mm Hg difference in blood pressure and the development of cardiac hypertrophy.
Key Words: angiotensin II renin inhibition n-3 PUFA arrhythmias magnetocardiography
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