TUNEL: a useful screening method in sudden cardiac death

Area of Science:

• Cardiovascular Pathology
• Cellular Biology
• Forensic Pathology

Background:

• Myocardial ischemia diagnosis relies on identifying cardiac cell death.
• Apoptosis (programmed cell death) is a key cellular process.
• Distinguishing ischemia-induced apoptosis from other causes is clinically important.

Purpose of the Study:

• To evaluate apoptosis detection in myocardial tissue for diagnosing early myocardial ischemia.
• To assess the utility of the terminal deoxynucleotidyl transferase-mediated desoxyuridinetriphosphate nick end-labeling (TUNEL) method in identifying apoptotic changes.

Main Methods:

• Analysis of myocardial tissue from autopsy cases: coronary artery disease (CAD) with infarction, sudden cardiac death without CAD, and controls.
• Histological examination using hematoxylin-erythrosin-saffron, Mallory's PTAH stain, and complement C9 antibodies for necrosis.
• Visualization of apoptotic nuclei using two TUNEL kits on histological sections.

Main Results:

• Apoptotic myocyte nuclei were widespread in the myocardium, not confined to necrotic lesions.
• A mean of 29% of myocyte nuclei showed apoptosis in CAD patients and 24% in sudden cardiac death cases.
• No significant difference in apoptosis rates was observed between patients with and without CAD (p > 0.05).
• TUNEL staining was extensive and appeared early in the myocardium.

Conclusions:

• Apoptosis detection in the heart, particularly using the TUNEL method, shows promise as a screening approach.
• While TUNEL staining is extensive, it's uncertain if all detected apoptosis is directly ischemia-induced.
• The TUNEL method appears valuable for screening in suspected sudden cardiac death cases.