Relationship between Dynamics of TNF-α and Its Soluble Receptors in Saliva and Periodontal Health State

Dynamic changes in macrophage polarization during the resolution phase of periodontal disease

AIM

Polarization of macrophages (Mφ) is a well-controlled axis with considerable consequences in both the pro-inflammatory and resolution phases of inflammation. We aimed to determine if periodontal therapy may instigate M1 to M2 Mφ polarization favoring resolution of inflammation within periodontal tissues.

METHODS

Gingival biopsies were excised from subjects diagnosed with Stage III, Grade B periodontitis before and 4-6 weeks after nonsurgical periodontal therapy. Total RNA was isolated and pro- and anti-inflammatory markers associated with Mφ polarization assessed by RT-qPCR. Mice were subject to ligature-induced periodontitis and gingival tissues collected after 8 days in-situ or 10 days after ligature removal and M1 and M2 Mφ markers examined by RT-qPCR and flow cytometry.

RESULTS

In human samples, improvement in clinical parameters posttherapy correlates with reduced bacterial burden, downregulation in M1 (TNF-α, STAT1, CXCL10, and miR-155), and elevated levels of M2 (STAT6, TGM2, CCL22, and IL-10) Mφ markers. In a murine model of resolution of LIP, we observed reduced levels of M1 Mφ markers cox2, iNOS2, F4/80+CD80+, and F4/80+CD86+ and elevated levels of M2-like Mφ markers tgm2, arg1, F4/80+CD206+ and F4/80+CD163+ corroborated human findings.

CONCLUSION

Resolution of periodontal inflammation is associated with M1 to M2 Mφ polarization after nonsurgical periodontal therapy. Assessment of Mφ markers can provide relevant clinical information on the successful response of periodontal therapy and may be used to target nonresponders.

SARS-CoV-2, periodontal pathogens, and host factors: The trinity of oral post-acute sequelae of COVID-19

COVID-19 as a pan-epidemic is waning but there it is imperative to understand virus interaction with oral tissues and oral inflammatory diseases. We review periodontal disease (PD), a common inflammatory oral disease, as a driver of COVID-19 and oral post-acute-sequelae conditions (PASC). Oral PASC identifies with PD, loss of teeth, dysgeusia, xerostomia, sialolitis-sialolith, and mucositis. We contend that PD-associated oral microbial dysbiosis involving higher burden of periodontopathic bacteria provide an optimal microenvironment for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. These pathogens interact with oral epithelial cells activate molecular or biochemical pathways that promote viral adherence, entry, and persistence in the oral cavity. A repertoire of diverse molecules identifies this relationship including lipids, carbohydrates and enzymes. The S protein of SARS-CoV-2 binds to the ACE2 receptor and is activated by protease activity of host furin or TRMPSS2 that cleave S protein subunits to promote viral entry. However, PD pathogens provide additional enzymatic assistance mimicking furin and augment SARS-CoV-2 adherence by inducing viral entry receptors ACE2/TRMPSS, which are poorly expressed on oral epithelial cells. We discuss the mechanisms involving periodontopathogens and host factors that facilitate SARS-CoV-2 infection and immune resistance resulting in incomplete clearance and risk for 'long-haul' oral health issues characterising PASC. Finally, we suggest potential diagnostic markers and treatment avenues to mitigate oral PASC.

Dietary inflammatory index in relation to salivary cytokine concentrations and periodontitis: A cross-sectional analysis

AIM

To examine the associations of dietary inflammatory index (DII) with salivary cytokine concentrations and periodontitis after controlling for body mass index (BMI), socio-demographic factors and lifestyle.

MATERIALS AND METHODS

Subgroups from two Finnish surveys, DILGOM 2007 and Health 2000, were included (total n = 727). The DII scores were calculated based on a food frequency questionnaire. Periodontal status was assessed with a cumulative risk score in DILGOM 2007 and by pocket depth measurement in Health 2000. From saliva, interleukin (IL)-1β, IL-1 receptor antagonist, IL-6, IL-8, IL-10 and tumour necrosis factor (TNF)-α concentrations were measured.

RESULTS

The DII scores did not differ between non-periodontitis and periodontitis participants in pairwise comparison. After adjusting for energy intake, periodontal status, BMI, age, education level, smoking habit and physical activity, DII was not associated with salivary cytokine concentrations. After adjusting for salivary cytokine levels and other confounding factors, DII was associated with periodontitis in the Health 2000 subgroup but not in the DILGOM 2007 subgroup.

CONCLUSIONS

The current data support the evidence that diet is not associated with salivary cytokine levels but may be associated with periodontitis. The association observed between diet and periodontitis is related to factors other than diet-dependent inflammatory tendency in the oral cavity.

Magnolia kobus Extract Inhibits Periodontitis-Inducing Mediators in Porphyromonas gingivalis Lipopolysaccharide-Activated RAW 264.7 Cells

Periodontitis, a disease caused by inflammation of oral bacteria, contributes to the loss of alveolar bone and destruction of connective tissues. Porphyromonas gingivalis, a Gram-negative bacterium, is known to possess important pathogenic factors for periodontal disease. In this study, we investigated the anti-periodontitis effects of Magnolia kobus extract (MKE) and magnolin as a component of Magnolia kobus (MK) in murine macrophage RAW 264.7 cells stimulated with Porphyromonas gingivalis lipopolysaccharide (LPS). Effects of MKE and magnolin on the mechanism of RAW 264.7 cellular inflammation were determined by analyzing nitric oxide (NO) production and Western blot protein expression (n = 3). MKE/magnolin inhibited NO production without affecting cell survival. MKE/magnolin treatment inhibited LPS-induced pro-inflammatory cytokines, expression levels of matrix metalloproteinases (MMPs such as MMP-1, 3, 8, 9, and 13), and protein levels of inflammatory mediators (such as TNF-α, IL-1β, and mPGES-1). MKE/magnolin also suppressed NF-κB activation by inhibiting the TLR4 signaling pathway. These findings suggest that MKE has a therapeutic effect on inflammatory periodontal disease caused by oral bacterium P. gingivalis and that magnolin is a major functional component in the anti-inflammatory effect of MKE.

Oral Microbiome Profiles and Inflammation in Pregnant Women Who Used Orthodontic Appliances

It is common for women to undergo orthodontic treatment during pregnancy, especially through the use of fixed orthodontic devices. In changing the oral microbiome profile, it is crucial to increase the immune responses of pregnant women using fixed orthodontics; however, changes in the microbiomes of pregnant women with orthodontic appliances can be adjusted. Therefore, we aimed to conduct research on the oral cavity microbiome profiles, specifically IL-6 and TNF-α, of pregnant women using fixed orthodontic appliances. We proposed an observational analysis of 30 third-trimester pregnant women. OHI-S was recorded, saliva collection was performed using the passive drool method for IL-6 and TNF-α, and analysis and mucosal swabs were used to determine the oral microbiome profile. Kruskal−Wallis and post hoc Bonferroni tests were used to identify any significant differences with values of p < 0.05. Of these pregnant women, those with orthodontic appliances developed 10 types of bacteria at similar levels (>80%) from the genera Streptococcus, Lactobacillus, and Veillonella. There was no difference between the oral microbiomes of the control group and the pregnant women with a history of orthodontic appliance use. While the level of TNF-α in the women with orthodontic appliances was higher compared with the control group who had never used orthodontic appliances (p < 0.05), there was no difference in the IL-6 levels. The IL-6 and microbiome profile produced normal results, so the use of orthodontic appliances during pregnancy should be allowed with conditions. Pregnant women with orthodontic appliances must keep the oral cavity clean and their appliances well-maintained to avoid oral problems.