From metabolic to epigenetic: Insight into trained macrophages in atherosclerosis (Review)

Atherosclerosis (AS) is a chronic inflammatory disease caused by the deposition of lipoproteins and sequent immune responses. Within the atherosclerotic plaque, macrophages are the most abundant immune cells and play a great part as protagonists and promoters of AS. In the past decade, the concept of 'trained immunity' has emerged, which highlights the memory characteristics of innate immunity, thus opening up a new avenue of research. Evidence suggests that trained immunity may regulate the onset and progression of AS with trained macrophages playing an important and dynamic role in atherogenesis. The present review provided a summary of concepts related to trained immunity and its relationship with AS. Furthermore, different phenotypes of macrophages responding to various stimuli within the atherosclerotic plaque were presented, along with the complex mechanisms of metabolic and epigenetic reprogramming in the cells. Finally, several promising therapeutic approaches for AS cardiovascular disease were discussed, which may shed light on new clinical strategies.