Assessing Cardiomyocyte DNA Damage Using Cardiovascular Magnetic Resonance T₁ Mapping: Insights From Comparative...

Area of Science:

• Cardiology
• Biomedical Imaging
• Molecular Cardiology

Background:

• DNA damage in cardiomyocytes is a critical factor in heart failure progression, preceding apoptosis and fibrosis.
• Cardiovascular magnetic resonance (CMR) T1 mapping's role in assessing this DNA damage remains unclear.

Purpose of the Study:

• To investigate the relationship between CMR T1 mapping parameters and cardiomyocyte DNA damage in patients with dilated cardiomyopathy (DCM).

Main Methods:

• 36 DCM patients underwent endomyocardial biopsy and serial 3T CMR scans before and after therapy.
• Native and postcontrast T1 mapping were used to quantify extracellular volume (ECV).
• DNA damage (poly(ADP-ribose)) and collagen volume fraction (CVF) were assessed in biopsy specimens.

Main Results:

• Native T1 and ECV strongly correlated with CVF. Native T1 moderately correlated with DNA damage severity, while ECV did not.
• Higher native T1 relative to ECV indicated significant DNA damage.
• Baseline DNA damage, not CVF, predicted myocardial tissue recovery and improved ejection fraction after therapy.

Conclusions:

• Native T1 mapping is effective for detecting both DNA damage and fibrosis in DCM.
• An elevated native T1/ECV ratio suggests early myocardial injury preceding fibrosis.
• DNA damage assessment may have implications for predicting treatment response and myocardial recovery.