TLR4 Expression Is Associated with Left Ventricular Dysfunction in Patients Undergoing Coronary Artery Bypass Surgery

Area of Science:

• Immunology
• Cardiology
• Molecular Biology

Background:

• Toll-like receptor 4 (TLR4) is an innate immune receptor found in immune cells and the heart.
• Immune system activation post-myocardial ischemia releases proinflammatory mediators that can impair heart function.

Purpose of the Study:

• To investigate TLR4 activation in monocytes and heart tissue of patients with coronary artery disease and varying degrees of myocardial dysfunction.
• To assess changes in TLR4 expression before and after coronary artery bypass graft (CABG) surgery.

Main Methods:

• Compared patients with reduced left ventricular ejection fraction (EF ≤ 45%) to those with preserved EF (>45%) undergoing CABG.
• Measured TLR4 expression in peripheral monocytes and heart tissue (right auricle).
• Assessed plasma levels of C-reactive protein, miR-320a, pro BNP, and NOX4.

Main Results:

• Patients with reduced EF showed significantly higher monocyte TLR4 expression compared to preserved EF group.
• Elevated TLR4 gene expression in the right auricle correlated with lower EF, higher NOX4, and higher miR-320a levels.
• Monocyte TLR4 expression decreased in all patients post-CABG, notably in the reduced EF group.

Conclusions:

• TLR4 is activated in monocytes and heart tissue of patients with ischemic heart disease and reduced left ventricular function.
• Coronary revascularization via CABG surgery leads to decreased TLR4 expression.
• TLR4 may play a pathogenic role and serve as a marker for ischemic myocardial dysfunction.