Tissue Resident Macrophages in the Heart in Cardiovascular Disease
The innate immune cells known as macrophages can be found in tissues throughout the body, where they perform many functions. Macrophages do not just find and destroy pathogens and potentially problematic cells, they also help to coordinate regeneration from injury. They can take on pro-inflammatory or anti-inflammatory states depending on circumstances. Researchers are interested in finding ways to reduce inflammation and promote greater regeneration by manipulating macrophage state and activities, and here the focus is on macrophages resident in the heart, an organ that exhibits relatively little regenerative capacity following injury.
Macrophages are essential factors of the body's innate immune system and mononuclear phagocyte system and are widely present in the structure of the tissues, including the heart. Cardiac macrophages play an integral physiological role to regulate the physiological and pathological processes of the cardiovascular system. Resident macrophages are heterogeneous and plastic, and multiple subsets with different phenotypes and functions are present in the same tissue and are involved in different pathophysiological processes. There is increasing evidence suggesting that cardiac-resident macrophage populations play a critical role in regulating heart development, electrical conduction, and ventricular remodelling processes.
The mechanisms used by cardiac macrophages to influence cardiovascular disease (CVD) vary and include both direct and indirect interactions with other cardiac cells. In particular, the identification of specific targets for cardiac resident macrophages to regulate CVD would be crucial. Due to the development of various exogenous (using delivery of toxic substances, blocking antibodies and small interfering RNAs) and genetic methods (transgenic methods) to broadly and specifically target these macrophage populations, this has provided us with the opportunity to understand the function of various cardiac and pericardial macrophages. Relatively few studies have addressed therapies targeting cardiac resident macrophages in patients with CVD although mechanistic knowledge about cardiac resident macrophages and their contribution to cardiovascular risk have accumulated in recent years.