Fig. 4

Severe visceral fat tissue inflammation in response to structural disruption. Excessive enlargement of adipocytes in response to chronic overnutrition eventually causes structural damage with dying adipocytes and cell senescence as hallmarks. The phagocytotic capacity of macrophages is overwhelmed and released DAMPS strongly activate resident immune and endothelial cells resulting in the attraction of virtually all types of immune cells. Their pro-inflammatory activation also stimulates anti-inflammatory activities. Another structural change is the accumulation of senescent cells, mostly macrophages, pre-adipocytes, mature adipocytes, and endothelial cells. Senescent cells secrete pro-inflammatory mediators and enhance the accumulation of immune cells from circulation. ATM, adipose tissue macrophages; DAMP, damage-associated molecular pattern; Mono, monocytes; EC, endothelial cell; CD8⁺, CD8-positive T cells