Fig. 1.

ATM accumulation through proliferation, recruitment, and retention. Macrophages accumulate in the adipose tissue through cell division, recruitment and retention. Recruitment can be driven by MCP-1 [112, 117]. Local proliferation occurs especially in the early stage of obesity [111, 113, 114] and is induced by IL-4, IL-6 and MCP-1 [111, 113, 128]. Retention is mediated by direct adhesion of macrophages to adipocytes through the interaction of α4 on macrophages with VCAM-1 on adipocytes [115, 116] and netrin-1, the expression of which is induced in macrophages by palmitate [115]. ATM, adipose tissue macrophage; MCP-1, monocyte chemoattractant protein 1; IL, interleukin; VCAM-1, vascular cell adhesion molecule-1.