Targeted inhibition of activin receptor-like kinase 5 signaling attenuates cardiac dysfunction following myocardial infarction

Sih Min Tan, Yuan Zhang, Kim A. Connelly, Richard E. Gilbert, Darren J. Kelly

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Abstract

Following myocardial infarction (MI), the heart undergoes a pathological process known as remodeling, which in many instances results in cardiac dysfunction and ultimately heart failure and death. Transforming growth factor-β (TGF-β) is a key mediator in the pathogenesis of cardiac remodeling following MI. We thus aimed to inhibit TGF-β signaling using a novel orally active TGF-β type I receptor [activin receptor-like kinase 5 (ALK5)] inhibitor (GW788388) to attenuate left ventricular remodeling and cardiac dysfunction in a rat model of MI. Sprague-Dawley rats underwent left anterior descending coronary artery ligation to induce experimental MI and then were randomized to receive GW788388 at a dosage of 50 mg·kg -1·day-1 or vehicle 1 wk after surgery. After 4 wk of treatment, echocardiography was performed before the rats were euthanized. Animals that received left anterior descending coronary artery ligation demonstrated systolic dysfunction, Smad2 activation, myofibroblasts accumulation, collagen deposition, and myocyte hypertrophy (all P < 0.05). Treatment with GW788388 signifi-cantly attenuated systolic dysfunction in the MI animals, together with the attenuation of the activated (phosphorylated) Smad2 (P < 0.01), α-smooth muscle actin (P < 0.001), and collagen I (P < 0.05) in the noninfarct zone of MI rats. Cardiomyocyte hypertrophy in MI hearts was also attenuated by ALK5 inhibition (P < 0.05). In brief, treatment with a novel TGF-β type I receptor inhibitor, GW788388, significantly reduced TGF-β activity, leading to the attenuation of systolic dysfunction and left ventricular remodeling in an experimental rat model of MI.

Original languageEnglish
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume298
Issue number5
DOIs
Publication statusPublished - May 2010
Externally publishedYes

Keywords

  • Cardiac remodeling
  • Heart failure
  • Interstitial fibrosis

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