Roles of Macrophage Subtypes in Bowel Anastomotic Healing and Anastomotic Leakage

Figure 1

Polarization of macrophages in normal healing of anastomosis. Inactivated macrophages can be stimulated by various stimuli (e.g., PAMP, DAMP/IL-4, and IL-13/apoptotic cell) and polarize into M1- or M2- (M2a, M2c) type macrophages during different phases of normal anastomotic healing. Differentiated macrophages express a variety of cytokines (e.g., IL-1β, IL-6, IL-10, and TNF-α), growth factors (e.g., VEGF), and enzymes (MMPs). These biochemical substances acting upon tissues contribute to tissue repair and remodeling. PAMP: pathogen-associated modifying patterns; DAMP: damage-associated modifying patterns; IL: interleukin; TNF-α: tumor necrosis factor-α; VEGF: vascular endothelial growth factor; MMPs: matrix metalloproteinases.