Highly Reactive Isolevuglandins Promote Atrial Fibrillation Caused by Hypertension

Area of Science:

• Cardiovascular Research
• Oxidative Stress Biology
• Molecular Medicine

Background:

• Oxidative damage is linked to atrial fibrillation (AF), but antioxidant therapies have proven ineffective.
• The precise mechanisms driving AF, particularly during hypertension, remain incompletely understood.
• Reactive lipid dicarbonyl metabolites, specifically isolevuglandins (IsoLGs), are emerging as key contributors to cellular damage.

Purpose of the Study:

• To test the hypothesis that isolevuglandins (IsoLGs) are principal drivers of atrial fibrillation (AF) in the context of hypertension.
• To investigate the potential of scavenging IsoLGs as a therapeutic strategy to prevent AF.
• To explore the role of natriuretic peptides and their interaction with IsoLGs in atrial pathology.

Main Methods:

• Utilized a hypertensive murine model to study AF susceptibility.
• Employed stretched atriomyocytes in vitro to investigate cellular mechanisms.
• Administered the dicarbonyl scavenger 2-hydroxybenzylamine (2-HOBA) and its ineffective analog 4-hydroxybenzylamine (4-HOBA).
• Assessed IsoLG adducts, preamyloid oligomers (PAOs), and AF susceptibility.

Main Results:

• The dicarbonyl scavenger 2-hydroxybenzylamine (2-HOBA) effectively prevented IsoLG adducts and preamyloid oligomers (PAOs) in both the murine model and atriomyocytes.
• 2-HOBA treatment significantly reduced AF susceptibility in the hypertensive murine model.
• The ineffective analog 4-hydroxybenzylamine (4-HOBA) demonstrated minimal protective effects.
• Natriuretic peptides were found to generate cytotoxic oligomers, a process exacerbated by IsoLGs, leading to atrial PAO formation.

Conclusions:

• Isolevuglandins (IsoLGs) are identified as principal drivers of atrial fibrillation (AF) during hypertension.
• Scavenging reactive downstream oxidative stress mediators like IsoLGs represents a promising therapeutic approach for AF prevention.
• Targeting IsoLG-mediated pathways offers a novel strategy beyond traditional antioxidant therapies for cardiovascular diseases.