Analysis of vascular distribution and growth factors in human gingival tissue associated with periodontal probing depth

Vascular Changes and Hypoxia in Periodontal Disease as a Link to Systemic Complications

The hypoxic microenvironment caused by oral pathogens is the most important cause of the disruption of dynamic hemostasis between the oral microbiome and the immune system. Periodontal infection exacerbates the inflammatory response with increased hypoxia and causes vascular changes. The chronicity of inflammation becomes systemic as a link between oral and systemic diseases. The vascular network plays a central role in controlling infection and regulating the immune response. In this review, we focus on the local and systemic vascular network change mechanisms of periodontal inflammation and the pathological processes of inflammatory diseases. Understanding how the vascular network influences the pathology of periodontal diseases and the systemic complication associated with this pathology is essential for the discovery of both local and systemic proactive control mechanisms.

Dynamic analysis of Porphyromonas gingivalis invasion into blood capillaries during the infection process in host tissues using a vascularized three-dimensional human gingival model

Porphyromonas gingivalis, the pathogen of periodontal disease, is thought to be involved in various diseases throughout the body via gingival tissue blood capillaries. However, the dynamic analysis of the infection mechanism, particularly the deep invasion process of the gingival tissue, has not yet been elucidated because of the lack of both in vivo and in vitro models. In this study, we developed a vascularized three-dimensional (3D) gingival model with an epithelial barrier expressing cell-cell junctions using collagen microfibers (CMFs) to enable the dynamic analysis of the P. gingivalis invasion process. Lipid raft disruption experiments in the gingival epithelial cell layer demonstrated that P. gingivalis migrates into the deeper epithelium via the intercellular pathway rather than intracellular routes. P. gingivalis was shown to invade the 3D gingival model, being found inside blood capillaries during two days of culture. Notably, the number of bacteria had increased greatly at least two days later, whereas the mutant P. gingivalis lacking the cysteine proteases, gingipains, showed a significantly lower number of survivors. The secretion of interleukin-6 (IL-6) from the gingival tissue decreased during the two days of infection with the wild type P. gingivalis, but the opposite was found for the mutant suggesting that P. gingivalis infection disturbs IL-6 secretion at an early stage. By allowing the dynamic observation of the P. gingivalis invasion from the epithelial cell layer into the blood capillaries for the first time, this model will be a powerful tool for the development of novel therapeutics against periodontal infection related diseases.

Sulfonylureas for Treatment of Periodontitis-Diabetes Comorbidity-Related Complications: Killing Two Birds With One Stone

Periodontitis is one of the most prevalent oral inflammatory diseases leading to teeth loss and oral health problems in adults. Periodontitis mainly affects periodontal tissue by affecting the host immune system and bone homeostasis. Moreover, periodontitis is associated with various systemic diseases. Diabetes is a metabolic disease with systemic effects. Both periodontitis and diabetes are common inflammatory diseases, and comorbidity of two diseases is linked to exacerbation of the pathophysiology of both diseases. Since bacterial dysbiosis is mainly responsible for periodontitis, antibiotics are widely used drugs to treat periodontitis in clinics. However, the outcomes of antibiotic treatments in periodontitis are not satisfactory. Therefore, the application of anti-inflammatory drugs in combination with antibiotics could be a treatment option for periodontitis-diabetes comorbidity. Anti-diabetic drugs usually have anti-inflammatory properties and have shown beneficial effects on periodontitis. Sulfonylureas, insulin secretagogues, are the earliest and most widely used oral hypoglycemic drugs used for type-2 diabetes. Studies have found that sulfonylurea drugs can play a certain role in the mitigation of periodontitis and inflammation. This article reviews the effects of sulfonylurea drugs on the mitigation of periodontitis-diabetes comorbidity-related inflammation, bone loss, and vascular growth as well as the involved molecular mechanisms. We discuss the possibility of a new application of sulfonylureas (old drug) to treat periodontitis-diabetes comorbidity.

Multispecies biofilms and host responses: "discriminating the trees from the forest"

Periodontal diseases reflect a tissue destructive process of the hard and soft tissues of the periodontium that are initiated by the accumulation of multispecies bacterial biofilms in the subgingival sulcus. This accumulation, in both quantity and quality of bacteria, results in a chronic immunoinflammatory response of the host to control this noxious challenge, leading to collateral damage of the tissues. As knowledge of the characteristics of the host-bacterial interactions in the oral cavity has expanded, new knowledge has become available on the complexity of the microbial challenge and the repertoire of host responses to this challenge. Recent results from the Human Microbiome Project continue to extend the array of taxa, genera, and species of bacteria that inhabit the multiple niches in the oral cavity; however, there is rather sparse information regarding variations in how host cells discriminate commensal from pathogenic species, as well as how the host response is affected by the three-dimensional architecture and interbacterial interactions that occur in the oral biofilms. This review provides some insights into these processes by including existing literature on the biology of nonoral bacterial biofilms, and the more recent literature just beginning to document how the oral cavity responds to multispecies biofilms.