Innate Immune Cells in the Adipose Tissue in Health and Metabolic Disease

• Published in: Journal of innate immunity Vol. 14; no. 1; pp. 4 - 30
• Main Authors: Michailidou, Zoi, Gomez-Salazar, Mario, Alexaki, Vasileia Ismini
• Format: Journal Article
• Language: English
• Published: Basel, Switzerland S. Karger AG 01.01.2022; Karger Publishers
• Subjects: Adipose Tissue; chronic inflammation; Diabetes Mellitus, Type 2; endothelium; Humans; hypoxia; Immunity, Innate; Inflammation; innate immune cells; Insulin Resistance; Killer Cells, Natural; Metabolic Diseases; obesity; physical exercise; Review; Review Article; Physical exercise; Obesity; Adipose tissue; Chronic inflammation; Innate immune cells; Hypoxia; Endothelium
• ISSN: 1662-811X; 1662-8128
• DOI: 10.1159/000515117

Metabolic disorders, such as obesity, type 2 diabetes mellitus, and nonalcoholic fatty liver disease, are characterized by chronic low-grade tissue and systemic inflammation. During obesity, the adipose tissue undergoes immunometabolic and functional transformation. Adipose tissue inflammation is driven by innate and adaptive immune cells and instigates insulin resistance. Here, we discuss the role of innate immune cells, that is, macrophages, neutrophils, eosinophils, natural killer cells, innate lymphoid type 2 cells, dendritic cells, and mast cells, in the adipose tissue in the healthy (lean) and diseased (obese) state and describe how their function is shaped by the obesogenic microenvironment, and humoral, paracrine, and cellular interactions. Moreover, we particularly outline the role of hypoxia as a central regulator in adipose tissue inflammation. Finally, we discuss the long-lasting effects of adipose tissue inflammation and its potential reversibility through drugs, caloric restriction, or exercise training.