Phenotypic heterogeneity of cardiac macrophages during wound healing following myocardial infarction: perspectives in clinical research

Purpose. Myocardial regeneration is one of the most ambitious goals in prevention of adverse cardiac remodeling. Macrophages play a key role in transition from inflammatory to regenerative phase during wound healing following myocardial infarction (MI). We have accumulated data on macrophage properties ex vivo and in cell culture. However, there is no clear information about phenotypic heterogeneity of cardiac macrophages in patients with MI. The purpose of the project was to assess cardiac macrophage infiltration during wound healing following myocardial infarction in clinical settings taking into consideration experimental knowledge. Material and Methods. The study included 41 patients with fatal MI type 1. In addition to routine analysis, macrophages infiltration was assessed by immunohistochemistry. We used CD68 as a marker for the cells of the macrophage lineage, while CD163, CD206, and stabilin-1 were considered as M2 macrophage biomarkers. Nine patients who died from noncardiovascular causes comprised the control group. Results. The intensity of cardiac macrophage infiltration was higher during the regenerative phase than during the inflammatory phase. Results of immunohistochemical analysis demonstrated the presence of phenotypic heterogeneity of cardiac macrophages in patients with MI. We noticed that numbers of CD68+, CD163+, CD206+, and stabilin-1+ macrophages depended on MI phase. Conclusion. Our study supports prospects for implementation of macrophage phenotyping in clinic practice. Improved understanding of phenotypic heterogeneity might become the basis of a method to predict adverse cardiac remodeling and the first step in developing myocardial regeneration target therapy.