Table 1. Role of macrophage in metabolic control.

Metabolic tissue	Resident macrophage	Physiological/pathological role
Hypothalamus	Microglia	Appetite control
Liver	Kupffer cell	Control of hepatocyte metabolism
		Liver steatosis and fibrosis
		Insulin resistance
Pancreatic islet	Resident macrophage	β cell development
		Islet inflammation and β cell dysfunction
Adipose tissue	Resident macrophage	Lipid handling
		Adipogenesis
		Insulin resistance
Skeletal muscle	Resident macrophage	Regeneration
		Insulin resistance

Resident macrophages in metabolic organs are crucial to metabolic control in the steady state. Impairment in the physiological functions of tissue-resident macrophages, which can occur with aging, may contribute to age-related organ dysfunction. Macrophages may also mediate chronic inflammatory processes and tissue dysfunction in obesity.