Defective Intercellular Adhesion Complex in Myocardium Predisposes to Infarct Rupture in Humans Original Research Article

Objectives Our goal was to evaluate intercellular adhesion complex proteins in myocardium in human infarct rupture. Background Infarct rupture, a fatal complication of myocardial infarction (MI), has been attributed to a defective cell adhesion complex in a transgenic mouse model. Methods Heart samples were collected from autopsies from infarct rupture and control (nonrupture) MI patients. Both infarcted and remote areas were included. Cell adhesion proteins including αE-catenin, β-catenin, γ-catenin, and N-cadherin were characterized by immunohistochemistry and immunoblotting. Genetic analysis was undertaken to evaluate mutations and polymorphisms in the αE-catenin gene. In addition, infarct rupture was studied in transgenic mice heterozygous for αE-catenin C-terminal deficiency, mimicking the situation in human infarct rupture patients. Results No αE-catenin was detected in 70% of remote samples of infarct rupture hearts compared with 20% in control MI by immunohistochemistry. The immunoblot analysis confirmed a significant reduction in remote areas, and complete absence of αE-catenin in infarct areas from infarct rupture patients. No mutation or polymorphism of the αE-catenin gene was discovered. Other cell adhesion proteins were not significantly affected in remote areas of infarct rupture hearts. Three-fourths of the heterozygous αE-catenin C-terminal truncated mice died of infarct rupture, compared with one-fourth of the wild-type littermates. Conclusions The data show a reduced expression and defective localization of αE-catenin in the intercalated disc region in patients dying of infarct rupture. The mechanism of lower expression of αE-catenin remains to be elucidated.