Cardiac Mast Cells: Underappreciated Immune Cells in Cardiovascular Homeostasis and Disease.

Mast cells are multifarious immune cells with complex roles in tissue homeostasis and disease. They produce a plethora of mediators that play roles in inflammation, angiogenesis, lymphangiogenesis, and tissue remodeling. Recent insights into the heterogeneity of cardiac mast cell (CMC) subpopulations have renewed interest in their functional diversity in homeostasis and disease. They are located within the human heart in the myocardium, in atherosclerotic plaques, in the aortic valve, and in close proximity to nerves. Their plasticity enables different and even opposite functions in response to changing tissue contexts. These characteristics render CMCs intriguing, with a dichotomous role in protecting against, or accelerating, cardiovascular diseases. Future work should aim to identify CMC subsets, which could reveal novel therapeutic opportunities for cardiovascular disorders.