Alterations in macrophage polarization play a key role in control and development of periodontal diseases

Abstract

Periodontitis is a chronic inflammatory disease driven by complex interplays between a dysbiotic oral microbiome and a dysregulated host inflammatory response that results in the destruction of the tooth-supporting apparatus. Among the inflammatory cells involved in the pathogenesis of periodontitis, macrophages are recruited early on to sites of periodontal infection. These cells can polarize in different phenotypes that mediate the initiation and resolution of inflammatory responses, as well as in tissue healing. Macrophage phenotypic plasticity is thought to play a critical role in the induction and resolution of inflammation and may be compromised in patients with chronic inflammatory diseases. Here, we reviewed the role of macrophage polarization in periodontal disease and therapy.

Keywords: Gingivitis; immunomodulation; inflammation; macrophages; periodontitis.

Figure 1

Macrophage phenotypic modulation as a strategy in periodontal therapy and regeneration. The immunomodulation of macrophage phenotypes from M1 to M2 (alternative activation) promotes the release of anti-inflammatory cytokines, growth factors and lipid mediators, and arginase 1 expression, which are involved in the resolution of the inflammatory process and wound healing. Just as a sustained increase in the M1 macrophage population can lead to exaggerated inflammation and inflammation-driven periodontal destruction, immunomodulation toward the M2 phenotype favors the resolution of inflammation and osteoclastogenesis and improves the outcomes of regenerative periodontal treatments through recruitment and activation of multiple mesenchymal cell types. IL-4 – Interleukin-4, IL-10 – Interleukin-10; IL-13 – Interleukin-13; ARG1 – Arginase 1; TGF-β – Transforming growth factor-β, VEGF – Vascular endothelial growth factor, EGF – Epidermal growth factor; PDGF – Platelet-derived growth factor; 15d-PGJ2 – Anti-inflammatory lipid mediators 15-deoxy-delta-12,14-prostaglandin J2; MSC – Mesenchymal stem cells