Adipose tissue macrophages: phenotypic plasticity and diversity in lean and obese states

• Published in: Current opinion in clinical nutrition and metabolic care Vol. 14; no. 4; p. 341
• Main Authors: Morris, David L, Singer, Kanakadurga, Lumeng, Carey N
• Format: Journal Article
• Language: English
• Published: England 01.07.2011
• Subjects: Adipose Tissue - cytology; Adipose Tissue - physiopathology; Animals; CD11c Antigen - metabolism; Ceramides - metabolism; Fibrosis; Humans; Inflammation - physiopathology; Lectins, C-Type - metabolism; Lipodystrophy - physiopathology; Lipolysis; Macrophages - metabolism; Mannose-Binding Lectins - metabolism; Mice; Mice, Obese; Obesity - physiopathology; Phenotype; Receptors, Cell Surface - metabolism; Thinness - physiopathology; Triglycerides - metabolism
• ISSN: 1473-6519
• DOI: 10.1097/MCO.0b013e328347970b

Proinflammatory adipose tissue macrophages (ATMs) contribute to obesity-associated disease morbidity. We will provide an update of the current state of knowledge regarding the phenotypic and functional diversity of ATMs in lean and obese mice and humans. The phenotypic diversity of ATMs is now known to include more than two types requiring an expansion of the simple concept of an M2 to M1 shift with obesity. Potential functions for ATMs now include the regulation of fibrosis and response to acute lipolysis in states of caloric restriction. Novel pathways that can potentiate ATM action have been identified, which include inflammasome activation and the response to lipodystrophic adipose tissue. Studies provide a new appreciation for the ability of ATMs to respond dynamically to the adipose tissue microenvironment. ATMs play a key role in shaping the inflammatory milieu within adipose tissue, and it is now apparent that ATM heterogeneity is acutely shaped by the adipose tissue environment. To account for the new findings, we propose a new nomenclature for ATM subtypes that takes into account their diversity.