Interaction of Macrophages with Bone Healing Microenvironment: Mechanism and Biomaterials.

Extensive bone fractures, which can seriously impact both health and quality of life, cannot easily heal naturally, especially if the patient has an underlying medical condition or is aging. The most promising approach to addressing such fractures is bone regeneration through bone tissue engineering. Bone regeneration is a complex process that consists of three distinct phases: inflammation, repair, and remodeling. Macrophages play a bridging role between the various cells involved in each stage of bone regeneration, interacting with different microenvironments and advancing the bone healing process. Although the origin and function of macrophages have been extensively studied, the mechanisms underlying their interaction with the bone healing microenvironment remain unexplored, including the association of microenvironmental changes with macrophage reprogramming and the role of macrophages in cells in the microenvironment. This review summarizes the bone regeneration process and recent advances in research on interactions between macrophages and the bone healing microenvironment and discusses novel biological strategies to promote bone regeneration by modulating macrophages for the treatment of bone injury and loss.

Polarized Macrophages in Periodontitis: Characteristics, Function, and Molecular Signaling.

Periodontitis (PD) is a common chronic infectious disease. The local inflammatory response in the host may cause the destruction of supporting periodontal tissue. Macrophages play a variety of roles in PD, including regulatory and phagocytosis. Moreover, under the induction of different factors, macrophages polarize and form different functional phenotypes. Among them, M1-type macrophages with proinflammatory functions and M2-type macrophages with anti-inflammatory functions are the most representative, and both of them can regulate the tendency of the immune system to exert proinflammatory or anti-inflammatory functions. M1 and M2 macrophages are involved in the destructive and reparative stages of PD. Due to the complex microenvironment of PD, the dynamic development of PD, and various local mediators, increasing attention has been given to the study of macrophage polarization in PD. This review summarizes the role of macrophage polarization in the development of PD and its research progress.

Alteration of salivary microbiome in periodontitis with or without type-2 diabetes mellitus and metformin treatment.

We aimed to explore the effects of type-2 diabetes mellitus (T2DM) and hypoglycemic therapy on the salivary microbiome in periodontitis patients and identify the potential salivary micro-biomarker for the early warning of T2DM. Saliva samples were collected from healthy individuals (Health), periodontitis patients (P), T2DM patients, periodontitis patients with T2DM (DAP), and DAP patients treated with Metformin (Met). Samples were determined by16S rRNA gene sequencing. 29 phyla, 322 genera, and 333 species of salivary microbiome were annotated. Compared to the Health group, the P and DAP group showed a significantly higher diversity of saliva microbiota, while the T2DM and Met group had no significant difference in microbial abundance but showed a trend of increasing diversity. Other than well-known periodontitis-inducing pathogens, the proportion of Prevotella copri, Alloprevotella rava, and Ralstonia pickettii, etc. were also significantly increased in periodontitis patients with or without T2DM. After effective glycemic control, the abundance of Prevotella copri, Alloprevotella rava, Ralstonia pickettii, etc. decreased in periodontitis patients with companion T2DM. The accuracies of the classification models in differentiating Health-vs.-P, DAP-vs.-P, and T2DM-vs.-P were 100%, 96.3%, and 98.1%, respectively. Hypoglycemic therapy could reconstruct the saliva microbiota and hence improve the localized conditions of diabetes patients with periodontitis.