Polarization of monocyte-derived M1-like and M2-like macrophages in patients with ST-segment elevation myocardial infarction

Background: M1-like and M2-like macrophages are found in acute myocardial infarction, but their activation during and after ST-segment elevation myocardial infarction (STEMI) in humans is unclear. Methods: Circulating cytokines were measured in 50 patients sampled on day 1 (STEMI) and day 5 (post-STEMI), and healthy subjects ( n = 22). Moreover, monocyte-derived M1-like and M2-like macrophages from the three groups were polarized and activated to analyze their phenotype and function ( n = 14/group). Results: STEMI and post-STEMI patients showed elevated levels of CD80, CD86 and inflammatory cytokines such as TNF-α in M1-like macrophages, whereas the levels of CD36, CD206, and anti-inflammatory cytokines such as IL-10 were elevated in M2-like macrophages. Additionally, compared with the conditioned medium of M2-like macrophages, that of M1-like macrophages induced the expression of molecules such as CD54 and CD31 on HUVECs in STEMI and post-STEMI patients. Finally, the levels of pro- and anti-inflammatory cytokines and MMP-9 in M1-like and M2-like macrophages were similar in the plasma of STEMI and post-STEMI patients, whereas the plasma level of IL-6 was decreased in post-STEMI patients. Conclusions: M1-like and M2-like macrophages may participate simultaneously in STEMI and post-STEMI by secreting cytokines and metalloproteinases and through endothelial activation. Furthermore, these cells may contribute to the circulating cytokine microenvironment in these patients.