Cardioprotective Effects of Dietary Flaxseed Post-Infarction Are Associated with Changes in MicroRNA Expression

Area of Science:

• Cardiovascular Research
• Molecular Biology
• Nutritional Science

Background:

• MicroRNAs (miRNAs) are critical in cardiac remodeling post-myocardial infarction (MI), influencing apoptosis, fibrosis, and arrhythmias.
• Dietary flaxseed has shown cardioprotective effects against MI.
• The specific miRNA targets and mechanisms of flaxseed's cardioprotective action remain to be fully elucidated.

Purpose of the Study:

• To investigate whether dietary flaxseed supplementation modulates specific cardiac microRNAs (miRNAs) following myocardial infarction (MI).
• To test the hypothesis that flaxseed's cardioprotective effects are mediated by regulating miRNAs involved in cardiac remodeling.

Main Methods:

• Rats underwent MI induction via coronary artery ligation and were randomized into groups receiving sham surgery or MI with normal chow, milled flaxseed, flaxseed oil (rich in alpha-linolenic acid - ALA), or flaxseed lignans.
• Supplementation occurred for 2 weeks pre-surgery and 8 weeks post-surgery.
• Cardiac miRNA and collagen I expression levels were analyzed.

Main Results:

• Dietary flaxseed oil supplementation selectively upregulated cardiac expression of miR-133a, miR-135a, and miR-29b.
• The flaxseed oil group exhibited reduced levels of collagen I expression, indicating decreased cardiac fibrosis.
• Milled flaxseed and flax lignan supplementation did not show the same specific miRNA upregulation or collagen reduction.

Conclusions:

• miR-133a, miR-135a, and miR-29b are sensitive to dietary flaxseed oil, likely due to its high alpha-linolenic acid (ALA) content.
• Flaxseed oil's cardioprotective effects post-MI may be attributed to its ability to modulate these specific miRNAs.
• These findings highlight a potential nutritional strategy for managing cardiac remodeling after MI through miRNA regulation.