Innate immunity represents the semi-specific first line of defense and provides the initial host response to tissue injury, trauma, and pathogens. Innate immunity activates the adaptive immunity, and both act highly regulated together to establish and maintain tissue homeostasis. Any dysregulation of this interaction can result in chronic inflammation and autoimmunity and is thought to be a major underlying cause in the initiation and progression of highly prevalent immune-mediated inflammatory diseases (IMIDs) such as psoriasis, rheumatoid arthritis, inflammatory bowel diseases among others, and periodontitis. Th1 and Th2 cells of the adaptive immune system are the major players in the pathogenesis of IMIDs. In addition, Th17 cells, their key cytokine IL-17, and IL-23 seem to play pivotal roles. This review aims to provide an overview of the current knowledge about the differentiation of Th17 cells and the role of the IL-17/IL-23 axis in the pathogenesis of IMIDs. Moreover, it aims to review the association of these IMIDs with periodontitis and briefly discusses the therapeutic potential of agents that modulate the IL-17/IL-23 axis.

In periodontitis patients, dysbiosis of the oral microbiota is not only found at clinically diseased periodontal sites but also at clinically healthy periodontal sites, buccal mucosae, tongue, and saliva. The present study evaluated the safety and efficacy of an oral microbiota transplant (OMT) for the treatment of periodontitis in dogs. Eighteen systemically healthy beagle dogs with naturally occurring periodontitis were enrolled in the study and randomly assigned to a test or control group. A 4-y-old, periodontally healthy female beagle dog served as a universal OMT donor. To reduce periodontal inflammation, all dogs received full-mouth mechanical debridement of teeth and mucosae 2 wk before baseline. At baseline, full-mouth mechanical debridement was repeated and followed by adjunctive subgingival and oral irrigation with 0.1% NaOCl. Subsequently, test dogs were inoculated with an OMT from the healthy donor. No daily oral hygiene was performed after OMT transplantation. Adverse events were assessed throughout the observation period. Clinical examinations were performed and whole-mouth oral microbiota samples were collected at week 2, baseline, week 2, and week 12. The composition of oral microbiota samples was analyzed using high-throughput 16S ribosomal RNA gene amplicon sequencing followed by taxonomic assignment and downstream bioinformatic and statistical analyses. Results demonstrated that the intergroup difference in the primary outcome measure, probing pocket depth at week 12, was statistically insignificant. However, the single adjunctive OMT had an additional effect on the oral microbiota composition compared to the full-mouth mechanical and antimicrobial debridement alone. The OMT resulted in an “ecological shift” toward the composition of the donor microbiota, but this was transient in nature and was not observed at week 12. No local or systemic adverse events were observed throughout the study period. The results indicate that OMT may modulate the microbiota composition in dogs with naturally occurring periodontitis and can be applied safely.

Objectives: Indicators of oral and periodontal diseases have previously been associated with handgrip strength and muscle mass and function in older adults in several populations. However, research in middle-aged adults on the relationship between periodontitis and handgrip strength and skeletal muscle mass – another important indicator of sarcopenia – has been limited. This study investigated the association between periodontitis and sarcopenia indicators in middle-aged adults from a U.S. population. Materials and Methods: Adults with complete periodontal and whole-body dual x-ray absorptiometry examinations from the 2013–2014 wave of the National Health and Nutrition Examination Survey (NHANES) were analysed using fully adjusted multiple linear regression models for associations between periodontitis diagnosis and severity and skeletal muscle mass index (SMMI) and combined handgrip strength (cHGS). Results: A subset of 1,912 individuals with a complete periodontal examination and whole-body dual x-ray absorptiometry scan from the NHANES 2013–2014 main cohort (n = 10,683) were included in the analysis. The median age of the participants was 43 years. Overall, 32% of the participants (n = 612) were determined to have periodontitis. Of these, 513 (26.8%) had non-severe (mild or moderate) periodontitis, and 99 (5.2%) had severe periodontitis. Both non-severe and severe periodontitis showed significant associations with cHGS (ß = -2.28, 95% CI -3.57–-0.98 and ß = -2.84, 95% CI -5.37–-0.31, respectively), but not with SMMI. Conclusion: The findings of the current study indicate that periodontitis and handgrip strength are interrelated. The present study highlights the need of further prospective research to investigate the nature and direction of the relationship between periodontitis and sarcopenia indicators. Clinical relevance: Future studies can support the screening, prevention and clinical management of sarcopenia and periodontitis, and emphasize the interdisciplinary and complementary approach between the disciplines of geriatric medicine and periodontology.