Triiodothyronine protects infarcted myocardium by reducing apoptosis and preserving mitochondria

Area of Science:

• Cardiology
• Endocrinology
• Molecular Biology

Background:

• Myocardial infarction (MI) is a major cause of heart failure.
• Thyroid hormone (TH) signaling is crucial for cardiac function and recovery.
• Current TH therapies for cardiac patients have inconsistent outcomes and unclear mechanisms.

Purpose of the Study:

• To evaluate the long-term cardioprotective effects of acute triiodothyronine (T3) administration post-MI.
• To investigate the molecular mechanisms underlying T3's cardioprotective actions.
• To assess T3's impact on left ventricle (LV) remodeling and function after infarction.

Main Methods:

• A cryoinjury mouse model of left ventricle (LV) infarction was used.
• Two doses of triiodothyronine (T3) were administered immediately after injury and 24 hours later.
• Echocardiography and molecular analyses were performed 28 days post-injury.

Main Results:

• T3 administration significantly reduced scar expansion and prevented LV hypertrophy.
• Improved LV remodeling and function were observed 28 days post-MI.
• T3 reduced apoptosis in the peri-infarcted area and prevented mitochondrial damage by inhibiting acylcarnitine accumulation.

Conclusions:

• Acute T3 treatment following MI demonstrates significant long-term benefits for LV function and remodeling.
• T3's cardioprotective effects are mediated by reduced apoptosis and preserved mitochondrial integrity.
• This study supports T3 as a potential therapeutic agent for improving post-MI recovery.