Survival and cardioprotective benefits of long-term blueberry enriched diet in dilated cardiomyopathy following myocardial infarction in rats

Abstract

Background: Despite remarkable progress in treatment of chronic heart failure (CHF) over the last two decades, mortality, personal suffering and cost remain staggering, and effective interventions are still a challenge. Previously we reported that a blueberry-enriched diet (BD) attenuated necroapoptosis and inflammation in periinfarct area in a rat model of myocardial infarction (MI).

Objectives: To test the hypothesis that BD will attenuate the course of CHF, including mortality and cardiac remodeling during the first year after induction of MI in rats.

Method and results: Two weeks after coronary artery ligation, rats were divided into two groups of similar average MI size, measured by echocardiography, and then 12-mo dietary regimens were initiated as follows: ad libitum regular diet (control, CD, n = 27) and isocaloric food with 2% blueberry supplement (BD, n = 27) also available ad libitum. These dietary groups were compared to each other and to sham group (SH). Mortality over the 12 mo was reduced by 22% in BD compared with CD (p<0.01). In the course of developing CHF, BD had no effect on the body weight, heart rate or blood pressure. Bi-monthly Echo revealed significant attenuation of the LV chamber remodeling, LV posterior wall thinning, and MI expansion in BD compared with CD. In fact, BD arrested the MI expansion.

Conclusion: This is the first experimental evidence that a blueberry-enriched diet has positive effects on the course of CHF and thus warrants consideration for clinical evaluation.

Figure 1. 12-mo survival after MI.

Kaplan-Meier survival curves following induction of MI in a sham operated group (SH- n = 10), and two groups with MI maintained on control diet (CD - n = 27) or blueberry-enriched diet (BD - n = 27).

Figure 2. Effect of blueberry-enriched diet on basic physiological parameters.

Body weight (A), heart rate (B), and arterial blood pressure (C). Note, results of blood pressure measurements are not available for the first 2 time points.

Figure 3. Effect of blueberry-enriched diet on MI expansion.

MI expansion was measured by echocardiography (A, B) and histologically (C) in all animals and in animals that survived 12 months following induction of MI.

Figure 4. Effect of blueberry-enriched diet on cardiac remodeling.

LV end-diastolic volume (left panels), end-systolic volume (middle panels), and ejection fraction (right panels) estimated by bi-monthly Echo during 12 months following induction of MI in rats maintained on control or blueberry-enriched diets. Upper panels - all animals. Lower panels - only animals that survived 12 months following induction of MI.

Figure 5. Effect of blueberry-enriched diet on cardiac remodeling.

LV mass (A) and posterior wall thickness (B) estimated by bi-monthly Echo during 12 months following induction of MI in rats maintained on control or blueberry-enriched diets and in sham operated rats.