Macrophages: A review of their role in wound healing and their therapeutic use.

Macrophages are mononuclear phagocytes established during embryogenesis and derived from the yolk sac or the fetal liver but also recruited from the blood and bone marrow under proliferative inflammatory conditions (such as tissue repair). Most importantly, they take on distinct phenotypes and functions crucial to healing upon localization in the wound. The objective of this review is to summarize recent findings in regard to the cellular mechanisms of macrophages and chronic wounds. Advances in the potential use of macrophage therapy have arisen based, in part, on the fact that early recruitment of macrophages is critical to wound healing. Higher quality evidence is needed to support the use of macrophage therapy for chronic wound types, as is a better understanding of the signaling related to macrophage polarization, activation of macrophages, and their effect of mechanisms of repair. An evaluation of the currently available research on mechanism of action may lead to a better understanding of the signaling processes of the many macrophage phenotypes, as well as their roles and outcomes in wound healing, which could then guide the development and eventual widespread use of macrophage therapies.