Chronic adipose tissue inflammation: all immune cells on the stage

• Different immune cells in visceral adipose tissue are actively involved in inflammatory processes during obesity.
• Their recruitment to adipose tissue and distinct cytokine profile is a hallmark of obesity/type 2 diabetes and can be targeted for therapeutic purposes.

Inflammation is indispensable for host homeostasis against invading pathogens and efficient wound healing upon tissue malfunction and has to be tightly controlled by various mechanisms to limit excess responses harmful to host tissues. A myriad of disease conditions ranging from type 2 diabetes (T2D) to neurodegenerative and cardiovascular disorders are now shown to progress due to persistent, unresolved inflammation in metabolic tissues such as adipose, liver, pancreas, muscle, and brain. However, their underlying mechanisms are incompletely understood. The actions of innate and adaptive immune cells in these ailments are increasingly appreciated so much so that a new research area called ‘immunometabolism’ has emerged. In this review, we will highlight the fundamental roles of various immune cells in adipose tissue during the initiation and progression of obesity-induced inflammation and discuss potential anti-inflammatory therapies from different mechanistic points of view.