Macrophage mediators and mechanisms in cardiovascular disease.

Macrophages are major players in myocardial infarction (MI) and atherosclerosis, two major cardiovascular diseases (CVD). Atherosclerosis is caused by the buildup of cholesterol-rich lipoproteins in blood vessels, causing inflammation, vascular injury, and plaque formation. Plaque rupture or erosion can cause thrombus formation resulting in inadequate blood flow to the heart muscle and MI. Inflammation, particularly driven by macrophages, plays a central role in both atherosclerosis and MI. Recent integrative approaches of single-cell analysis-based classifications in both murine and human atherosclerosis as well as experimental MI showed overlap in origin, diversity, and function of macrophages in the aorta and the heart. We here discuss differences and communalities between macrophages in the heart and aorta at steady state and in atherosclerosis or upon MI. We focus on markers, mediators, and functional states of macrophage subpopulations. Recent trials testing anti-inflammatory agents show a major benefit in reducing the inflammatory burden of CVD patients, but highlight a necessity for a broader understanding of immune cell ontogeny and heterogeneity in CVD. The novel insights into macrophage biology in CVD represent exciting opportunities for the development of novel treatment strategies against CVD.