Figure 2.

The Role of Macrophage Phenotypes in Wound Healing. Acute wounds progress through the phases of inflammation, proliferation and remodeling as they heal. In inflammation, pro-inflammatory macrophages are present. Their role is to phagocytose dead cells and bacteria and prepare the wound for healing. In proliferation, pro-wound healing macrophages are present. They secrete factors that aid in angiogenesis, formation of granulation tissue, collagen deposition, and reepithelialization. In remodeling, pro-resolving macrophages aid in breakdown of the provisional granulation tissue to allow for maturation of collagen and strengthening of the newly regenerated skin. Below the diagrams are the general roles and timing of different macrophage phenotypes during the wound healing process. Differences between in vivo and in vitro classifications are separated by the dashed line, however similar roles can be seen between many of the phenotypes. The timing is an estimate based on the role of each phenotype, and has not been experimentally confirmed.