Objectives: We examined the effects of the flavanol (-)-epicatechin on short- and long-term infarct size and left ventricular (LV) structure and function after permanent coronary occlusion (PCO) and the potential involvement of the protective protein kinase B (AKT)/extracellular signal-related kinase (ERK) signaling pathways.
Background: (-)-epicatechin reduces blood pressure in hypertensive patients and limits infarct size in animal models of myocardial ischemia-reperfusion injury. However, nothing is known about its effects on infarction after PCO.
Methods: (-)-epicatechin (1 mg/kg daily) treatment was administered via oral gavage to 250 g male rats for 10 days before PCO and was continued afterward. The PCO controls received water. Sham animals underwent thoracotomy and treatment in the absence of PCO. Immunoblots assessed AKT/ERK involvement 2 h after PCO. The LV morphometric features and function were measured 48 h and 3 weeks after PCO.
Results: In the 48-h group, treatment reduced infarct size by 52%. There were no differences in hemodynamics among the different groups (heart rate and aortic and LV pressures). Western blots revealed no differences in AKT or ERK phosphorylation levels. At 3 weeks, PCO control animals demonstrated significant increases in LV end-diastolic pressure, heart and body weight, and LV chamber diameter versus sham. The PCO plus (-)-epicatechin group values were comparable with those of the sham plus (-)-epicatechin group. Treatment resulted in a 33% decrease in myocardial infarction size. The LV pressure-volume curves demonstrated a right shift in control PCO animals, whereas the (-)-epicatechin curves were comparable with those of the sham group. The LV scar area strains were significantly improved with (-)-epicatechin.
Conclusions: These results demonstrate the unique capacity of (-)-epicatechin to confer cardioprotection in the setting of a severe form of myocardial ischemic injury. Protection is sustained over time and preserves LV structure and function. The cardioprotective mechanism(s) of (-)-epicatechin seem to be unrelated to AKT or ERK activation. (-)-epicatechin warrants further investigation as a cardioprotectant.
Copyright (c) 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.