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Angiotensin converting enzyme inhibitor prevents left ventricular remodelling after myocardial infarction in angiotensin II type 1 receptor knockout mice
  1. M Yoshiyama1,
  2. Y Nakamura1,
  3. T Omura1,
  4. Y Izumi2,
  5. R Matsumoto1,
  6. S Oda1,
  7. K Takeuchi1,
  8. S Kim2,
  9. H Iwao2,
  10. J Yoshikawa1
  1. 1Department of Internal Medicine and Cardiology, Graduate School of Medicine, Osaka City University, Osaka, Japan
  2. 2Department of Pharmacology, Graduate School of Medicine, Osaka City University
  1. Correspondence to:
    Dr Minoru Yoshiyama
    Department of Internal Medicine and Cardiology, Graduate School of Medicine, Osaka City University, 1-4-3, Asahi-machi, Abeno-ku, Osaka, 545-8585, Japan;


Background: It is well known that angiotensin converting enzyme (ACE) inhibitors and angiotensin II type 1 (AT1) receptor blockers (ARBs) prevent left ventricular (LV) remodelling after myocardial infarction (MI). However, it is still not clear whether inhibition of the AT1 receptor is enough to prevent LV remodelling after MI.

Objective: To elucidate the effects of ACE inhibitors that are not mediated by the AT1 receptor on LV remodelling, MI was experimentally induced in wild-type (WT-MI) mice and AT1 receptor knockout (KO-MI) mice.

Methods: Mice were divided into six groups: WT-control, KO-control, WT-MI, KO-MI, WT-MI treated with an ACE inhibitor, and KO-MI treated with an ACE inhibitor. Four weeks after MI, cardiac function was assessed by Doppler echocardiography and non-infarcted myocardial mRNA expression by northern blot analysis.

Results: Cardiac function decreased significantly in the MI groups compared with the sham operated groups. Additionally, in the MI groups end diastolic dimension, E wave velocity, the ratio of peak velocity of E wave to A wave, deceleration rate of E wave, and mRNA expression of atrial natriuretic peptide, brain natriuretic peptide, and collagens I and III increased significantly compared with the sham groups. LV remodelling after MI was prevented in KO-MI mice compared with WT-MI mice. ACE inhibitor administration significantly attenuated progressive LV remodelling in both WT and KO-MI groups.

Conclusion: ACE inhibitors can prevent the LV remodelling process that accompanies cardiac dysfunction after MI, even in AT1 KO mice. These findings suggest that ACE inhibitors prevent LV remodelling after MI by mechanisms other than inhibition of angiotensin AT1 receptor mediated effects.

  • ACE, angiotensin converting enzyme
  • ANP, atrial natriuretic peptide
  • ARB, angiotensin II type 1 receptor blocker
  • AT1, angiotensin II type 1
  • BNP, brain natriuretic peptide
  • CHARM, candesartan in heart failure–assessment of reduction in mortality and morbidity
  • %FS, percentage of fractional shortening
  • KO, knockout
  • LV, left ventricular
  • MI, myocardial infarction
  • RV, right ventricular
  • Val-HefT, valsartan heart failure trial
  • WT, wild type
  • Doppler echocardiography
  • angiotensin II type 1 receptor knockout mice
  • cardiac genes
  • left ventricular remodelling
  • myocardial infarction

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