Figure 2.

Effects of OSA on macrophages derived from adipose tissues and tumors. Tissue macrophages are composed of different subpopulations exerting different physiological properties. The two well-known subtypes are: M1 (classically activated macrophages) with pro-inflammatory properties, and M2 (alternatively activated macrophages) with anti-inflammatory properties. Macrophages are capable of dynamic inter-conversion depending on the immediate environment in which they evolve, and obesity or OSA increases tissue infiltration of macrophages and polarization towards the M1 phenotype (A). During tumor progression, circulating monocytes and macrophages are actively recruited into tumors where they alter the tumor microenvironment to accelerate tumor progression. The M1 macrophage is involved in the inflammatory response, pathogen clearance, and antitumor immunity. In contrast, the M2 macrophage influences an anti-inflammatory response, wound healing, and pro-tumorigenic properties (B).