Ganoderma Microsporum Immunomodulatory Protein Alleviates Inflammaging and Oxidative Stress in Diabetes-Associated Periodontitis via Nrf2 Signaling Activation: An In Vitro Study

Periodontitis, characterized by inflammation and loss of periodontal tissue, is a significant health complication for individuals with diabetes mellitus (DM). Buildup of advanced glycation end-products (AGEs) in DM poses an increased risk of periodontitis via inflammaging. Ganoderma immunomodulatory protein (GMI) shows promise in suppressing inflammaging by mitigating oxidative stress and inflammation via Nrf2 modulation. However, its specific protective effects are not fully understood. Thus, this study aimed to investigate GMI's anti-inflammaging properties and its underlying mechanism in diabetic-associated periodontitis (DP). We first simulated DP by culturing human gingival fibroblasts (HGFs) with AGEs and lipopolysaccharides from P. gingivalis (LPS). We then evaluated the impact of GMI on cell proliferation, migration and wound healing. Additionally, we assessed GMI's effects on the components of inflammaging such as reactive oxygen species (ROS) formation, cellular senescence expression, IL-6 and IL-8 secretions, and NF-κB phosphorylation. Next, we explored whether GMI's anti-inflammaging effects are mediated through the Nrf2 pathway by evaluating Nrf2 and HO-1, followed by the assessment of IL-6 and IL-8 post-Nrf2 knockdown. Our findings revealed that GMI treatment suppressed ROS production, cell senescence, IL-6 and IL-8 and NF-κB phosphorylation. Furthermore, GMI upregulated Nrf2/HO-1 expression and its protective effects were reversed when Nrf2 was knocked down. In conclusion, GMI exerts its anti-inflammaging effect via the modulation of the Nrf2/NF-κB signaling axis in DP in vitro, highlighting its potential as an effective adjunct treatment for diabetes-related periodontitis.

Molecular hydrogen suppresses Porphyromonas gingivalis lipopolysaccharide-induced increases in interleukin-1 alpha and interleukin-6 secretion in human gingival cells

Periodontitis is defined as a multifactorial polymicrobial infection accompanied by inflammatory reactions. Porphyromonas gingivalis (Pg) is known as a major pathogen in the initiation and progression of periodontitis, and a major virulence factor is Pg lipopolysaccharide (LPS). Molecular hydrogen (H₂) has been reported to act as a gaseous antioxidant, which suppresses periodontitis progression by decreasing gingival oxidative stress. However, no human periodontitis model has examined the anti-inflammatory effects of H₂. In this study, we examined the effects of H₂ on Pg LPS-induced secretion of 8 types of inflammation markers in a human periodontitis model using human gingival cells with enzyme-linked immunosorbent assays. Our results demonstrated that Pg LPS increased interleukin (IL) 1 alpha (IL-1α) and IL-6 secretion, but H₂ significantly suppressed the secretion of both cytokines without cytotoxicity. H₂ can suppress the production of IL-1α and IL-6, which are identified as cytokines involved in inflammatory reactions in periodontal disease. Thus, H₂ may provide therapeutic applications for periodontitis.

Porphyromonas gingivalis lipopolysaccharides act exclusively through TLR4 with a resilience between mouse and human

Porphyromonas gingivalis is a key bacterium in chronic periodontitis, which is associated with several chronic inflammatory diseases. Lipopolysaccharides from P. gingivalis (Pg LPS) can activate multiple cell types via the production of pro-inflammatory cytokines. The receptors for Pg LPS have initially been reported as TLR2, contrasting with the well-studied TLR4 receptor for E. coli LPS; this observation remains controversial since synthetic Pg lipid A activates TLR4 but not TLR2. Despite this observation, the dogma of Pg LPS-mediated TLR2 activation remains the basis of many hypotheses and result interpretations. In the present work, we aimed at determining whether TLR4 or TLR2, or both, mediate Pg LPS pro-inflammatory activity using Pg LPS with different grades of purity, instead of synthetic lipid A from Pg LPS. Here we show that Pg LPS 1) acts exclusively through TLR4, and 2) are differently recognized by mouse and human TLR4 both in vitro and in vivo. Taken together, our results suggest that Pg LPS activity is mediated exclusively through TLR4 and only weakly induces proinflammatory cytokine secretion in mouse models. Caution should be taken when extrapolating data from mouse systems exposed to Pg or Pg LPS to humans.

Effect of application of a PVP-iodine solution before and during subgingival ultrasonic instrumentation on post-treatment bacteraemia: a randomized single-centre placebo-controlled clinical trial

BACKGROUND

To assess the effect of concomitant subgingival rinsing with 10% PVP-iodine during subgingival instrumentation on the prevalence and magnitude of bacteraemia of oral origin.

MATERIALS AND METHODS

Subgingival instrumentation was performed with water or PVP-iodine rinse in patients with periodontitis. Prior to instrumentation, subjects gargled for 1 min with the allocated liquid. Pockets were then rinsed for 1 min and subgingivally instrumented with liquid-cooled (water/PVP-iodine) ultrasonic scalers (1 min). Two minutes later, a blood sample from the arm vein was drawn using a lysis centrifugation blood culture system for quantitative microbiological analysis. Non-parametric statistical tests were performed to assess differences in the prevalence and extent of bacteraemia between groups.

RESULTS

Of the 19 samples in each group, oral-borne bacteraemia was detected in 10 of the control and 2 of the test samples. With an average of 3.0 [1; 5] colony forming units, significantly less bacteria and bacteraemia were found in the test group compared to the controls (12.2 [1; 46]) (p = 0.003). Anaerobic bacteria were not found in the test group.

CONCLUSIONS

Bacteraemia after subgingival instrumentation with concomitant PVP-iodine rinsing is reduced but not eliminated. Therefore, it might be recommended for patients at a high risk of endocarditis or infection of endoprostheses. However, preventive antibiotic treatment should not be omitted.

Determination of periodontopathogens in patients with Cri du chat syndrome

Objectives: Cri du chat syndrome is a genetic alteration associated with some oral pathologies. However, it has not been described previously any clinical relationship between the periodontal disease and the syndrome. The purpose of this comparative study was to compare periodontopathogenic flora in a group with Cri du chat syndrome and another without the síndrome, to assess a potential microbiological predisposition to suffer a periodontitis. Study Design: The study compared nineteen subjects with Cri du chat Syndrome with a control group of nineteen patients without it. All patients were clinically evaluated by periodontal probing, valuing the pocket depth, the clinical attachmente level and bleeding on probing. There were no significant differences between both groups. Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia and Treponema denticola were detected by multiplex-PCR using 16S rDNA (microIDENT). Results: When A. actinomycetemcomitans, P. gingivalis, P. intermedia and T. denticola were compared, no statistically significant differences were found between the two groups (p>0.05). The value of T. forsythia was significantly higher for Cri du chat syndrome (31.6%) than for the control group (5.3%). The odds ratio for T. forsythia was 8.3. Conclusions: In the present study T. forsythia is associated with Cri du chat syndrome subjects and not with healthy subjects.

Key words:Cri du Chat syndrome, periodontal health, microbiology, special care dentistry.

Effects of aging on endotoxin tolerance induced by lipopolysaccharides derived from Porphyromonas gingivalis and Escherichia coli

BACKGROUND

Periodontitis is a bacterially induced chronic inflammatory disease. Exposure of the host to periodontal pathogens and their virulence factors induces a state of hyporesponsiveness to subsequent stimulations, termed endotoxin tolerance. Aging has a profound effect on immune response to bacteria challenge. The aim of this study was to explore the effects of aging on endotoxin tolerance induced by Porphyromonas gingivalis (P. gingivalis) lipopolysaccharide (LPS) and Escherichia coli (E. coli) LPS in murine peritoneal macrophages.

METHODOLOGY/PRINCIPAL FINDINGS

We studied the cytokine production (TNF-α and IL-10) and Toll-like receptor 2, 4 (TLR2, 4) gene and protein expressions in peritoneal macrophages from young (2-month-old) and middle-aged (12-month-old) ICR mice following single or repeated P. gingivalis LPS or E. coli LPS stimulation. Pretreatment of peritoneal macrophages with P. gingivalis LPS or E. coli LPS resulted in a reduction in TNF-α production and an increase in IL-10 production upon secondary stimulation (p<0.05), and the markedly lower levels of TNF-α and higher levels of IL-10 were observed in macrophages from young mice compared with those from middle-aged mice (p<0.05). In addition, LPS restimulations also led to the significantly lower expression levels of TLR2, 4 mRNA and protein in macrophages from young mice (p<0.05).

CONCLUSIONS/SIGNIFICANCE

Repeated LPS stimulations triggered endotoxin tolerance in peritoneal macrophages and the ability to develop tolerance in young mice was more excellent. The impaired ability to develop endotoxin tolerance resulted from aging might be related to TLR2, 4 and might lead to the incontrollable periodontal inflammation in older adults.

Stage of hepatocellular carcinoma is associated with periodontitis

AIM

Periodontitis induces overproduction of reactive oxygen species (ROS). This state increases circulating ROS levels and may affect hepatocellular carcinoma (HCC). The Japan Integrated Stage (JIS) score is a novel staging system for HCC. The objective of the present study was to compare JIS scores in HCC patients with and without periodontitis.

MATERIAL AND METHODS

We recruited 64 HCC patients comprising 31 chronic periodontitis subjects (HCC + P) and 33 periodontally healthy controls (HCC + H). Their JIS scores were recorded. Serum levels of reactive oxygen metabolites (ROM) from HCC + P, HCC + H and healthy age- and gender-matched subjects with healthy gingiva (control, n = 15) were also assessed for circulating ROS levels.

RESULTS

The HCC + P and HCC + H groups had similar body mass index, habitual drinking and tobacco exposure data. The HCC + P group showed higher JIS scores than the HCC + H group (p = 0.027). Both the HCC + P and HCC + H groups had higher serum levels of ROM than controls (p < 0.001), while serum levels of ROM in the HCC + P group were a further 25.8% higher than those in the HCC + H group (p < 0.001).

CONCLUSION

HCC patients with periodontitis had higher JIS score and circulating ROS level than HCC patients without periodontitis.