Intersection between macrophages and periodontal pathogens in periodontitis

Periodontitis is a chronic infectious disease characterized by loss of periodontal attachment and resorption of alveolar bone. Dysregulated oral microbial community is the initial factor of periodontitis and causes excessive infiltration of immune cells in periodontal tissues. Macrophage, as an important part of the innate immune system, interacts continually with oral pathogens. Macrophages can recognize and phagocytize pathogens and apoptotic neutrophils and produce the specialized pro-resolving mediators (SPMs) playing an important role in maintaining the homeostasis of tissue microenvironment. However, macrophages may also induce abnormal immune responses with the overstimulation from pathogens, leading to the destruction of periodontal tissues and alveolar bone. Looking for targeted drugs that can regulate the activities of oral pathogens and the functions of macrophages provides a new idea for periodontitis treatment. This review summarizes the interaction between macrophages and periodontal pathogens in periodontitis, focusing on the pro-inflammation and anti-inflammation phenotypes of macrophages, and briefly concludes potential new methods of periodontitis therapy targeted at oral pathogens and macrophages.