Macrophages are a type of immune cell that can be found in most organs in the body. They remove harmful substances and dead cells from tissues, and contribute to homeostasis — stability among bodily systems.
Macrophages are metabolically plastic, meaning they can change their metabolism and function to match the needs of different organ environments. Their function may also be affected by changing environments.
For example, macrophages transition from a dormant to an inflammatory state in fatty tissue in obese individuals. This inflammatory state eventually contributes to conditions including metabolic syndrome, insulin resistance, and non-alcoholic fatty liver disease.