Decreased Myocardial Dendritic Cells is Associated With Impaired Reparative Fibrosis and Development of Cardiac Rupture After Myocardial Infarction in Humans

BACKGROUND Dendritic cells (DC) play pivotal roles in regulating the immune system and inflammatory response. We previously reported DC infiltration in the infarcted heart and its immunoprotective roles in the post-infarction healing process after experimental myocardial infarction (MI). However, its clinical significance has not been determined. METHODS AND RESULTS The degree of DC infiltration and its correlation with the post-infarction healing process in the human infarcted heart were investigated in 24 autopsy subjects after ST-elevation MI. Patients were divided into two groups according to the presence (n=13) or absence (n=11) of cardiac rupture. The numbers of infiltrated DC and macrophages and the extent of fibrosis in the infarcted area were examined. In the rupture group, CD68(+) macrophage infiltration was increased and CD209(+) DC, and CD11c(+) DC infiltration and the extent of reparative fibrosis were decreased compared with the non-rupture group, under matched baseline characteristics including the time from onset to death and use of revascularization. Furthermore, there was a significant positive correlation between the number of infiltrating CD209(+) DC, and CD11c(+) DC and the extent of reparative fibrosis. CONCLUSIONS Decreased number of DC in human-infarcted myocardial tissue was associated with increased macrophage infiltration, impaired reparative fibrosis, and the development of cardiac rupture after MI. These findings suggest a protective role of DC in post-MI inflammation and the subsequent healing process.