Reduced plakoglobin immunoreactivity in arrhythmogenic cardiomyopathy: methodological considerations

Area of Science:

• Cardiology
• Pathology
• Molecular Biology

Background:

• Arrhythmogenic cardiomyopathy (AC) is a desmosomal disease often affecting the right ventricle.
• Reduced junctional plakoglobin (JUP) signal at intercalated disks is a potential diagnostic marker for AC.
• Methodological variations in tissue preservation and antibody dilutions may impact JUP signal detection.

Purpose of the Study:

• To investigate the impact of tissue preservation and antibody dilutions on the detection of junctional plakoglobin (JUP) in arrhythmogenic cardiomyopathy (AC).
• To assess the reliability of JUP signal intensity as a diagnostic marker for AC under varying technical conditions.

Main Methods:

• Immunohistochemical analysis of autopsy and biopsy samples from 7 control and 25 AC patients (diagnosed by 2010 Task Force Criteria).
• Comparison of JUP and N-Cadherin signals on cryosections and formalin-fixed tissues.
• Evaluation of different antibody dilutions (e.g., 1:1000, 1:100000) in a blinded experimental setup.

Main Results:

• Reduced JUP signal was observed in 7/10 AC patients using formalin-fixed tissue with a 1:1000 antibody dilution, correctly classifying 77% of individuals.
• The disturbed JUP pattern on cryosections required a significantly higher antibody dilution (1:100000) for unmasking.
• Comparable detection rates were achieved on cryo-fixed (74%) and formalin-fixed (70%) material, provided a highly defined approach.

Conclusions:

• Reduced JUP immunoreactive signal at intercalated disks is detectable in a majority of AC patients.
• Detection of JUP changes is feasible on both cryo- and formalin-fixed tissues.
• Standardized and highly defined methodologies are crucial for reliable JUP detection in AC diagnosis.