Cytokine responses against periodontal infection: protective and destructive roles

Role of Salivary Biomarkers IL-1β and MMP-8 in Early Detection and Staging of Periodontal Disease

Background: Periodontal disease is a chronic inflammatory condition affecting the supporting tissues of the teeth. Early diagnosis is crucial for preventing severe complications. This study investigates and compares the utility of two salivary biomarkers, interleukin-1 beta (IL-1β) and matrix metalloproteinase-8 (MMP-8), in the early detection and staging of periodontal disease. Methods: This study included 189 patients, all of whom were evaluated both clinically and biologically. Each participant provided unstimulated saliva samples, which were analyzed using ELISA methods to quantify IL-1β and MMP-8 levels. Clinical periodontal data, including probing depth (3.9 ± 0.6 mm), clinical attachment loss (3.4 ± 0.6 mm), and Plaque Index (2.35 ± 0.55), were collected for all subjects. Biomarker concentrations were then correlated with these clinical parameters and with disease severity, classified according to the 2018 EFP/AAP criteria. Results: IL-1β levels (210 ± 95 pg/mL) were strongly associated with early gingival inflammation, while MMP-8 levels (185 ± 140 ng/mL) correlated with periodontal tissue destruction (p < 0.01). MMP-8 showed a higher sensitivity for diagnosing advanced stages (p = 0.002), whereas IL-1β was more effective in detecting early inflammatory changes (p = 0.01). Logistic regression identified MMP-8 as a significant predictor of advanced disease (coefficient 0.85, p < 0.001) and IL-1β as an indicator of early inflammation (coefficient 0.25, p = 0.02). Conclusions: Both biomarkers are valuable tools for the diagnosis and staging of periodontal disease. MMP-8 is relevant for identifying advanced cases, while IL-1β supports early detection. Their combined use may enhance diagnostic accuracy and guide personalized periodontal care.

Encapsulated Chlorhexidine Gel Use in Adolescents Undergoing Orthodontic Treatment: A Randomised Trial

INTRODUCTION

The majority of orthodontic patients present with plaquebiofilm and related manifestations in the early stages of active fixed orthodontic appliance use.

AIMS

To evaluate the effects of a slow-delivery chlorhexidine:beta-cyclodextrin (Cx:β-Cd) gel compared with those of free Cx free formulations on clinical parameters in patients undergoing treatment with fixed orthodontic appliances.

METHODS

Patients aged 12-18 years received prophylaxis and scaling and were randomised to treatment groups in a double-blinded manner. They were treated with Cx:β-Cd, Cx, or placebo gel for 15 or 30 days. Bleeding on probing and the visible plaque index were recorded, and gingival crevicular fluid samples were collected for the assessment of cytokine expression.

RESULTS

At 15 days, the Cx:β-Cd group exhibited significantly less BOP than did the Cx and control groups (P < 0.001; n = 116). At 15 days, notable decreases in tumour necrosis factor-α and interferon-γ expression, as well as a substantial increase in interleukin-10 expression, were observed in the Cx:β-Cd and Cx groups relative to the control group (P < 0.05). The molecular encapsulation gel resulted in greater saliva Cx concentrations than did the free Cx gel released concentrations of 800 ng g-1.

CONCLUSION

Cx:β-Cd gel is effective for the slow delivery of Cx, improving the gingival health of adolescents undergoing orthodontic treatment.

CLINICAL RELEVANCE

A single application of encapsulated Cx gel, was a more effective antiseptic than a free Cx application in fixed orthodontice appliance wearers.

Evaluation of Salivary Il-38 Levels in Periodontitis: A Cross-Sectional Study

The goal of the current study was to assess levels of salivary interleukin (IL)-38, IL-1β, and IL-10 in various periodontal clinical conditions. In total, 60 (20 healthy, 20 gingivitis, and 20 stage II-III, grade A-B periodontitis) subjects were included in the study. Demographic and clinical periodontal parameters were recorded. Samples were examined for IL-38, IL-1β, and IL-10 levels by means of enzyme-linked immunosorbent assay. Results demonstrated that the periodontitis group had significantly lower salivary IL-38 levels (P < 0.05) than the healthy group. Salivary IL-10 levels did not differ significantly between the groups (P > 0.05). The salivary IL-1β levels of gingivitis (P < 0.001) and periodontitis groups (P < 0.01) were significantly higher than those of the healthy group. The present study indicated that IL-38 level is decreased in periodontal disease. The results suggested a possible role of IL-38 in the periodontal inflammation process. Clarifying the mechanisms of IL-38 in the inflammatory process may contribute to the development of novel treatment strategies in periodontal diseases.

Circulating interleukin-27 is associated with the risk of chronic periodontitis and allergic rhinitis: A Mendelian randomization analysis

BACKGROUND

Chronic periodontitis (CP) and allergic rhinitis (AR) have attracted wide attention as global public health problems with high incidence. Recent studies have shown that circulating interleukin-27 (IL-27) is associated with the risk of CP and AR. The aim of this study is to analyze the causal effect between them using Mendelian randomization (MR).

METHODS

Bidirectional MR analyses were performed with the use of publicly available genome-wide association study (GWAS) data. Summary data on circulating IL-27, CP, and AR published in genome-wide association studies were collected. Instrumental variables (IV) were extracted using assumptions of correlation, independence and exclusivity as criteria. Inverse variance weighting (IVW) was used as the main method, combined with weighted median method (WM) and MR-Egger and other MR Analysis methods for causal inference of exposure and outcome. Cochran's Q and MR-Egger intercept were used for sensitivity analysis.

RESULTS

The IVW study showed a causal effect between increased circulating IL-27 levels and increased risk of CP (OR = 1.14, 95%CI = 1.02-1.26, p = .020). Similarly, the increase of circulating IL-27 level had a causal effect on the decreased risk of AR (OR = 0.88, 95%CI = 0.80-0.97, p = .012). In addition, IVW study found that there was a causal between the increased risk of CP and circulating IL-27 level (OR = 1.05, 95%CI = 1.01-1.10, p = .016). However, there was no significant causal relationship between the risk of AR and circulating IL-27 levels (OR = 0.97, 95%CI = 0.91-1.02, p = .209). no significant heterogeneity or horizontal pleiotropy was found in sensitivity analysis.

CONCLUSIONS

There is a causal effect between circulating IL-27 level and CP, AR, which will help to find new ideas and methods for the diagnosis and treatment of CP and AR.

Resolution of peri-implant mucositis following standard treatment: A prospective split-mouth study

BACKGROUND

Peri-implant mucositis (PIM) is a pathological precursor of peri-implantitis, but its pattern of conversion to peri-implantitis is unclear and complicated to diagnose clinically, while none of the available protocols yield complete disease resolution. The aim of this study was the evaluation of PIM responsiveness to standard anti-infective mechanical treatment (AIMT) at clinical and biomarker levels, and estimation of the diagnostic capacity of bone markers as surrogate endpoints and predictors.

METHODS

Systemically healthy outpatients presenting one implant exhibiting clinical signs of inflammation confined within the soft tissue (PIM) and one healthy control (HC) implant at a non-adjacent position were included. Clinical parameters and peri-implant crevicular fluid samples were collected baseline and 6 months following mechanical therapy, to assess the levels of RANKL, OPG, and IGFBP2. PIM clustering was performed using machine learning algorithms.

RESULTS

Overall, 38 patients met the inclusion criteria. Therapy resulted in the reduction of all clinical and biological indicators, but respective values remained significantly higher compared to HC. Clinical examination noted 30% disease resolution at the 6-month follow-up, while 43% showed no active bone resorption. OPG showed positive prognostic value for treatment outcome, while the clustering based on active bone resorption did not differ in terms of therapeutic effectiveness.

CONCLUSION

AIMT is effective in reducing the clinical and biological indicators of PIM, but complete clinical resolution was achieved in only 30% of the cases. Around one third of PIM patients exhibited active bone resorption bellow clinical detectability that was not associated with disease progression and poor treatment responsiveness.

Cytokine levels in the gingival crevicular fluid and their association with periodontal status of down syndrome patients: a cross-sectional study

OBJECTIVE

To evaluate cytokine levels of interleukin (IL)-1β, IL-4, IL-6, IL-17a, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ in the gingival crevicular fluid (GCF) of periodontal sites in individuals with Down syndrome (DS) and analyze their relationship with clinical periodontal parameters.

MATERIALS AND METHODS

A cross-sectional study was conducted with 49 DS patients and 32 individuals without DS (non-DS group). Periodontal probing depth (PPD), clinical attachment level (CAL), bleeding on probing (BoP), and visible plaque index (VPI) were evaluated. The periodontal sites were classified as shallow, moderate, and deep. GCF was collected in all shallow sites and, when present, in moderate and deep sites for the analysis of cytokine levels. The cytokines, IL-1β, IL-4, IL-6, IL-17a, TNF-α, and IFN-γ, were quantified using the Luminex® automatic analyzer system.

RESULTS

The DS group presented greater severity of periodontitis compared to the non-DS group (P = 0.005). The DS group showed a significant direct correlation of IL-1β and an inverse correlation of IFN-γ and IL-14 with all periodontal variables. In the analysis stratified by periodontal pocket depth, we observed a higher level of IFN-γ, IL-17a, IL-1β, and IL-6 in the shallow sites, and IL-17a, IL-1β, and IL-6 in deep pockets of DS group individuals. Multivariate models showed that higher levels of IL-1β, IL-4, IL-6, and IL-17a were associated with Down syndrome even after adjusting for periodontal status, sex, and age.

CONCLUSION

The findings suggest that people with DS have greater periodontal impairment and higher levels of cytokines in GCF, even in sites having clinical periodontal parameters similar to those of individuals without DS. These data reiterate the concept of an altered and less effective immune response in the population with DS in the face of a periodontal microbial challenge.

CLINICAL RELEVANCE

Elevated periodontal inflammation burden can be observed with higher cytokine levels in the gingival crevicular fluid of people with Down syndrome, especially IL-1, IL-4, IL-6, and IL-17, regardless of the stage of periodontitis.

Utility of gingival crevicular fluid components for periodontal diagnosis

Periodontal diseases are highly prevalent chronic diseases, and severe periodontitis creates functional and esthetic problems and decreases self-esteem for a large percentage of the older population worldwide. In many cases of periodontitis, there is no distinct tell-tale pain that motivates a patient to seek treatment, rather the signs become clinically detectable late, and typically when the disease has progressed to a problematic level for the life of the dentition. Early periodontal screening and diagnostics tools will provide early recognition of periodontal diseases and facilitate timely management of the disease to reduce tooth loss. To this goal, gingival crevicular fluid is easily sampled, can be repeatedly and non-invasively collected, and can be tested for potential biomarkers. Moreover, the site specificity of periodontal diseases enhances the usefulness of gingival crevicular fluid sampled from specific sites as a biofluid for diagnosis and longitudinal monitoring of periodontal diseases. The present review aimed to provide up-to-date information on potential diagnostic biomarkers with utility that can be assayed from gingival crevicular fluid samples, focusing on what is new and useful and providing only general historic background textually and in a tabulated format.

Oral Fluid Biomarkers for Peri-Implantitis: A Scoping Review

Peri-implantitis, a prevalent complication in dental implant therapy, poses a significant threat to long-term implant success. The identification of reliable biomarkers for the early detection and monitoring of peri-implantitis is crucial for timely intervention and improved treatment outcomes. Salivary and peri-implant sulcular fluid (PISF) biomarkers have become promising diagnostic tools in the field of implant dentistry. This scoping review aims to explore current studies in the literature on salivary and PISF biomarkers for peri-implantitis. A systematic search was conducted on 2 databases (PubMed and Scopus) to identify relevant studies published up to January 2023. A total of 86 articles were included, which underwent data extraction and analysis. Several biomarkers have been investigated in salivary and PISF samples for association with peri-implantitis. Investigations included a wide range of biomarkers, including inflammatory markers, matrix metalloproteinases and bone loss markers. The findings suggested that certain salivary and PISF biomarkers demonstrated potential in distinguishing healthy peri-implant conditions from peri-implantitis. Elevated levels of proinflammatory cytokines, such as interleukin-1β (IL-1β) and interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-α), and matrix metalloproteinases, have been consistently associated with peri-implantitis. Additionally, alterations in bone loss markers have shown potential as indicators of disease progression and treatment response. In conclusion, this scoping review provides an overview of current knowledge on salivary and PISF biomarkers for peri-implantitis. The identified biomarkers are promising as noninvasive diagnostic tools for early detection, monitoring, and personalised management of peri-implantitis. Future studies should focus on establishing standardised protocols and conducting well-designed clinical trials to validate the diagnostic accuracy and clinical relevance of these biomarkers.

Er:YAG laser suppresses pro-inflammatory cytokines expression and inflammasome in human periodontal ligament fibroblasts with Porphyromonas gingivalis-lipopolysaccharide stimulation

Background/purpose

Periodontitis is an inflammatory condition of the tooth-supporting structures triggered by the host's immune response towards the bacterial deposits around the teeth. It is well acknowledged that pro-inflammatory interleukin (IL)-6, IL-8, MCP-1 as well as the NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome, are the key modulators in the activation of this response. Erbium-doped yttrium-aluminium-garnet (Er:YAG) laser, a solid-state crystal laser have been commonly used in the treatment of periodontal diseases. However, little is understood about the molecular mechanism of the Er:YAG laser, especially in targeting the host immune response brought on by periodontal pathogens. Hence, the current study focused on the protective effects of Er:YAG laser on periodontitis in-vitro in terms of pro-inflammatory cytokines, chemokines and NLRP3 inflammasome expressions.

Materials and methods

Human periodontal ligament fibroblast (PDLFs) were first stimulated with lipopolysaccharides (LPS) from P. gingivalis (Pg-LPS) to simulate periodontitis. Cells were then irradiated with Er:YAG laser of ascending energy densities (3.6-6.3 J/cm2), followed by cell proliferation and wound healing assay. Next, the effects of Er:YAG laser on the expressions of IL-6, IL-8, MCP-1, NLRP3, and cleaved GSDMD were examined.

Results

Pg-LPS was found to reduce cell's proliferation rate and wound healing ability in PDLFs and these were rescued by Er:YAG laser irradiation. In addition, LPS stimuli resulted in a marked upregulation in the secretion of IL-6, IL-8 and MCP-1 as well as the mRNA and protein expression of NLRP3 and cleaved-GSDMD protein whereas Er:YAG laser suppressed the elicited phenomena.

Conclusion

To our knowledge, this is the first study to look into the laser's implication on the NLRP3 inflammasome in periodontitis models. Our study reveals a crucial role of Er:YAG laser in ameliorating periodontitis in-vitro through the modulation of IL-6, IL-8, MCP-1 and the NLRP3 inflammasome and highlights that the control of the NLRP3 inflammasome may become a potential approach for periodontitis.

Gene variants for the WNT pathway are associated with severity in periodontal disease

OBJECTIVE

Studies of Wnt variants-related to bone resorption in periodontitis are limited. The aim of this study was to establish the genotype and allele frequency of gene variants associated with the Wnt pathway in systemically healthy individuals with and without periodontitis (PD).

MATERIALS AND METHODS

One hundred fifty-seven systemically healthy individuals were evaluated, 90 with PD and 67 without PD. Periodontal clinical indexes, serological and clinical indices of inflammation, and the following variants associated with the Wnt pathway: DKK, SOST, LRP5, and KREMEN were analyzed by high resolution melting and confirmed by Sanger sequencing.

RESULTS

In the PD-free group, 67.2% of the individuals presented the variant for DKKrs1896367 (p = 0.008) and 82.6% had the variant for KREMEN rs132274 (p = 0.016). The heterozygous variant for the DKK rs1896367 polymorphism was associated with the absence of PD and lower severity OR: 0.33 (CI95% 0.15-0.70) and OR: 0.24 (CI95% 0.11-0.53), respectively. Similarly, KREMEN rs132274 was the homozygous variant associated with the absence of PD (OR: 0.33 (CI95% 0.13-0.88)). On the contrary, 85.6% of individuals with PD presented a variant for DKK rs1896368 (p = 0.042), all suffering severe forms of periodontitis.

CONCLUSION

The presence of DKKrs1896367 and KREMENrs132274 variants in individuals without PD suggests that these single nucleotide polymorphisms could be protective factors for bone loss in PD. A very interesting finding is that the DKKrs1896368 variant was found in a high percentage of severe cases, suggesting that the presence of this variant may be related to the severe bone loss observed in PD.

Plasmon resonance biosensor for interleukin-1β point-of-care determination: A tool for early periodontitis diagnosis

Among pro-inflammatory cytokines, Interleukin-1β is crucially involved in several inflammatory-based diseases and even cancer. Increased Interleukin-1β levels in oral fluids have been proposed as an early marker of periodontitis, a broadly diffused chronic inflammatory condition of periodontal-supporting tissues, leading eventually to tooth loss. We describe the development of a portable surface-plasmon-resonance-based optical fiber probe suitably coated with an anti-Interleukin-1β antibody monolayer. A pico-nanomolar linear range of determination was obtained in both buffer solution and saliva with a rapid (3 min) incubation and high selectivity in presence of interferents. Higher Interleukin-1β concentration in the saliva of a periodontitis patient compared to a healthy control was determined. These measurements were validated by an automated ELISA system. Our results sustain the potential applicability of the proposed SPR-POF as diagnostic point-of-care device for real-time monitoring of salivary Interleukin-1β, that can support early detection of oral inflammatory-based pathologies and rapid and timely therapeutic decisions.

Notopterol Inhibits the NF-κB Pathway and Activates the PI3K/Akt/Nrf2 Pathway in Periodontal Tissue

Notopterol, an active component isolated from the traditional Chinese medicine Notopterygium incisum Ting ex H.T. Chang, exerts anti-inflammatory activity in rheumatoid arthritis. However, its roles in suppression of inflammatory insults and halting progression of tissue destruction in periodontitis remain elusive. In this study, we reveal that notopterol can inhibit osteoclastogenesis, thereby limiting alveolar bone loss in vivo. In vitro results demonstrated that notopterol administration inhibited synthesis of inflammatory mediators such as IL-1β, IL-32, and IL-8 in LPS-stimulated human gingival fibroblasts. Mechanistically, notopterol inhibits activation of the NF-κB signaling pathway, which is considered a prototypical proinflammatory signaling pathway. RNA sequencing data revealed that notopterol activates the PI3K/protein kinase B (Akt)/NF-E2-related factor 2 (Nrf2) signaling pathway in LPS-stimulated human gingival fibroblasts, a phenomenon validated via Western blot assay. Additionally, notopterol treatment suppressed reactive oxygen species levels by upregulating the expression of antioxidant genes, including heme oxygenase 1 (HO-1), NAD(P)H quinone oxidoreductase 1 (NQO1), catalase (CAT), and glutathione reductase (GSR), indicating that notopterol confers protection against oxidative stress. Notably, inhibition of Akt activity by the potent inhibitor, MK-2206, partially attenuated both anti-inflammatory and antioxidant effects of notopterol. Collectively, these results raise the possibility that notopterol relieves periodontal inflammation by suppressing and activating the NF-κB and PI3K/AKT/Nrf2 signaling pathways in periodontal tissue, respectively, suggesting its potential as an efficacious treatment therapy for periodontitis.

The homeostasis and therapeutic applications of innate and adaptive immune cells in periodontitis

OBJECTIVES

Periodontitis (PD) is one of the most common dental disorders. This chronic oral inflammation is caused by complicated interrelations between bacterial infections, dysregulated immune reactions, and environmental risk factors. A dysregulated immune response can lead to inflammatory bone resorption by allowing the recruitment of pro-inflammatory immune cells to the periodontal tissues.

SUBJECTS

The recruitment of innate and adaptive immune cells in PD initiates the acute and following chronic inflammatory processes. The inflamed tissues, on the other hand, can be restored if the anti-inflammatory lineages are predominantly established in the periodontal tissues. Therefore, we aimed to review the published literature to provide an overview of the existing knowledge about the role of immune cells in PD, as well as their possible therapeutic applications.

RESULTS

Experimental studies showed that drugs/systems that negatively regulate inflammatory cells in the body, as well as interventions aimed at increasing the number of anti-inflammatory cells such as Tregs and Bregs, can both help in the healing process of PD.

CONCLUSION

Targeting immune cells or their positive/negative manipulations has been demonstrated to be an effective therapeutic method. However, to use this sort of immunotherapy in humans, further pre-clinical investigations, as well as randomized clinical trials, are required.

Modeling periodontal host-microbe interactions using vascularized gingival connective tissue equivalents

Gingival connective tissue and its vasculature play a crucial role in the host's immune response against the periodontal microbiome and serve as a bridge between the oral and systemic environments. However, there is a lack of representative models that mimic the complex features of vascularized gingival connective tissue and its interaction with the periodontal microbiome, hindering our understanding of periodontal health and disease. Towards this pursuit, we present the characterization of vascularized gingival connective tissue equivalents (CTEs) as a model to study the interactions between oral biofilm colonizers and gingival tissues in healthy and diseased states. Whole-mount immunolabeling and label-free confocal reflectance microscopy of human fibrin-based matrix embedded with gingival fibroblasts and microvascular endothelial cells demonstrated the generation of bi-cellular vascularized gingival CTEs. Next, we investigated the response of the vascularized gingival CTEs to early, intermediate, and late oral biofilm colonizers. Despite colonization, the early colonizers did not elicit any significant change in the production of the cytokines and chemokines by the CTEs representative of the commensal and homeostatic state. In contrast, intermediate and late colonizers representing a transition to a diseased state exhibited connective tissue and vascular invasion, and elicited a differential immune response accompanied by increased monocyte migration. The culture supernatants produced by the vascularized gingival CTEs in response to early and intermediate colonizers polarized macrophages towards an immunomodulatory M2-like phenotype which activates and protects the host, while the late colonizers polarized towards a pro-inflammatory M1-like phenotype. Lastly,in silicoanalysis showed a high strength of associations between the proteins and transcripts investigated with periodontitis and vascular diseases. In conclusion, the vascularized gingival CTEs provide a biomimeticin vitroplatform to study host-microbiome interactions and innate immune response in periodontal health and diseased states, which potentially paves the way toward the development and assessment of novel periodontal therapeutics.

Zingerone-Induced Autophagy Suppresses IL-1β Production by Increasing the Intracellular Killing of Aggregatibacter actinomycetemcomitans in THP-1 Macrophages

Periodontitis is caused by the inflammation of tooth-supporting tissue by pathogens such as Aggregatibacter actinomycetemcomitans. Interleukin-1β (IL-1β), a pro-inflammatory cytokine, triggers a series of inflammatory reactions and promotes bone resorption. The aim of this study was to examine the molecular mechanism and anti-inflammatory function of zingerone, a dietary phenolic found in Zingiber officinale, on periodontal inflammation induced by A. actinomycetemcomitans. Zingerone attenuated A. actinomycetemcomitans-induced nitric oxide (NO) production by inhibiting the expression of inducible nitric oxide synthase (iNOS) in THP-1 macrophages. Zingerone also inhibited the expression of tumor necrosis factor (TNF)-α, IL-1β, and their signal pathway molecules including the toll-like receptor (TLR)/mitogen-activated protein kinase (MAPKase). In particular, zingerone suppressed the expression of absent in melanoma 2 (AIM2) inflammasome components on IL-1β production. Moreover, zingerone enhanced autophagosome formation and the expressions of autophagy-associated molecules. Interestingly, zingerone reduced the intracellular survival of A. actinomycetemcomitans. This was blocked by an autophagy inhibitor, which reversed the decrease in IL-1β production by zingerone. Finally, zingerone alleviated alveolar bone absorption in an A. actnomycetemcomitans-induced periodontitis mice model. Our data suggested that zingerone has potential use as a treatment for periodontal inflammation induced by A. actinomycetemcomitans.

Salivary cytokine expression after non-surgical periodontal therapy in smokers: 12-month follow-up

BACKGROUND

Diverse smoking trajectories may influence cytokine expression after non-surgical periodontal therapy and supportive periodontal care. Thus, we aimed to describe cytokine profiles in periodontal healing after periodontal therapy in smokers.

METHODS

A smoking cessation program and non-surgical periodontal therapy were offered to 80 smokers with periodontitis. Smoking trajectories (quitters/light, moderate, heavy) were observed. The association of salivary interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, interferon-gamma (IFN-γ), and tumor necrosis factor-alpha (TNF-α) with smoking trajectories and periodontal outcomes was determined using mixed-effects linear regression.

RESULTS

Among quitters/light smokers, IL-1β was associated with an increase in mean periodontal pocket depth (PPD) and mean clinical attachment level (CAL). IL-6 was associated with a decrease in mean PPD and CAL in heavy smokers, whereas IL-8 was associated with a decrease in PPD among moderate smokers. TNFα was associated with a reduction in mean PPD and CAL among quitters/light smokers, while among moderate smokers, TNFα was associated with an increase in mean PPD and CAL. IL-12 and IL-13 were associated with a decrease in mean PPD in moderate smokers.

CONCLUSION

Our findings suggest that distinctive smoking exposures induce differential cytokine expression, which, in turn, seems to influence periodontal repair.

DNA damage-inducible transcript 3 deficiency promotes bone resorption in murine periodontitis models

BACKGROUND AND OBJECTIVE

Periodontitis is a multifactorial inflammatory disease that leads to the destruction of supporting structures of the teeth. DNA damage-inducible transcript 3 (DDIT3) plays crucial roles in cell survival and differentiation. DDIT3 regulates bone mass and osteoclastogenesis in femur. However, the role of DDIT3 in periodontitis has not been elucidated. This research aimed to explore the role and mechanisms of DDIT3 in periodontitis.

METHODS

DDIT3 gene knockout (KO) mice were generated using a CRISPR/Cas9 system. Experimental periodontitis models were established to explore the role of DDIT3 in periodontitis. The expression of DDIT3 in periodontal tissues was detected by quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry (IHC). The alveolar bone phenotypes were observed by micro-CT and stereomicroscopy. The inflammation levels and osteoclast activity were examined by histological staining, immunostaining, and qRT-PCR. Bone marrow-derived macrophages (BMMs) were isolated to confirm the effects of DDIT3 on osteoclast formation and function in vitro.

RESULTS

The increased expression of DDIT3 in murine inflamed periodontal tissues was detected. DDIT3 knockout aggravated alveolar bone loss and enhanced expression levels of inflammatory cytokines in murine periodontitis models. Increased osteoclast formation and higher expression levels of osteoclast-specific markers were observed in the inflamed periodontal tissues of KO mice. In vitro, DDIT3 deficiency promoted the formation of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated osteoclasts and the bone resorption activity of mature osteoclasts.

CONCLUSIONS

Our results demonstrate that DDIT3 deletion aggravated alveolar bone loss in experimental periodontitis through enhanced inflammatory reactions and osteoclastogenesis. The anti-inflammation and the inhibition of bone loss by DDIT3 in murine periodontitis provides a potential novel therapeutic strategy for periodontitis.

A dual functional polypeptide with antibacterial and anti-inflammatory properties for the treatment of periodontitis

Periodontitis has been reported as the sixth most prevalent disease in human beings. This destructive disease is closely related to systemic diseases. Existing local drug delivery systems for periodontitis suffer from poor antibacterial effect and drug resistance. Inspired by the pathogenesis of periodontitis, we implemented a strategy to construct a dual functional polypeptide LL37-C15, which exhibited remarkable antibacterial effect against P. gingivalis and A. actinomycetemcomitans. In addition, LL37-C15 inhibits the release of pro-inflammatory cytokines by controlling the inflammatory pathway and reversing macrophage M1. Furthermore, the anti-inflammatory effect of LL37-C15 was also verified in vivo in a periodontitis rat model through the morphometry and histological observations of alveolar bone, hematoxylin-eosin, and Trap staining in gingival tissue. The results of molecular dynamics simulations showed that LL37-C15 could selectively destroy the bacterial cell membrane and protect the animal cell membrane in a self-destructive manner. The results showed that the polypeptide LL37-C15, as a novel promising therapeutic agent, exhibited a great potential for the periodontitis management. What's more, this dual functional polypeptide provides a promising strategy for building a multifunctional therapeutic platform against the inflammation and other diseases.

Sphingosine kinase activity and sphingosine-1-phosphate in the inflamed human periodontium

OBJECTIVES

This study evaluated changes in the levels of Sphingosine-1-Phosphate (S1P) and Sphingosine Kinase (SPHK) activity in response to non-surgical periodontal treatment in humans.

METHODS

Diseased (n = 65) and healthy sites (n = 72) were screened in 18 patients with localized periodontitis stage II or III. Periodontal clinical parameters were recorded, and the gingival crevicular fluid (GCF) collected at baseline, 30 and 90 days of non-surgical treatment. Internal control sites without attachment loss/bleeding were sampled at baseline and after 90 days of treatment. SPHK activity and S1P levels and SPHK 1/2 isoforms were determined in the GCF at different time points using ELISA.

RESULTS

Non-surgical treatment caused significant improvement in all periodontal clinical parameters (p < 0.01). Activity of SPHK and S1P levels was decreased (p < 0.05) 30 days after treatment and continued up to 90 days (p < 0.01); control sites remained unchanged throughout the study and resembled treated sites at 3 months (p > 0.05). SPHK1 levels presented decrease after periodontal treatment (p < 0.001). SPHK2 levels were lower than SPHK1 (p < 0.001) and remained unchanged.

CONCLUSIONS

S1P levels and SPHK activity decreased within 3 months of non-surgical periodontal treatment, which were correlated with improvements in periodontal parameters. Only SPHK1 levels varied significantly in the states of health and disease.

Is Periodontitis Associated with Age-Related Cognitive Impairment? The Systematic Review, Confounders Assessment and Meta-Analysis of Clinical Studies

It has been suggested that molecular pathological mechanisms responsible for periodontitis can be linked with biochemical alterations in neurodegenerative disorders. Hypothetically, chronic systemic inflammation as a response to periodontitis plays a role in the etiology of cognitive impairment. This study aimed to determine whether periodontitis (PDS) is a risk factor for age-related cognitive impairment (ACI) based on evidence of clinical studies. A comprehensive, structured systematic review of existing data adhering to the Preferred Reporting Items for Systematic Review and Meta Analyses (PRISMA) guidelines was carried out. Five electronic databases, PubMed, Embase, Scopus, Web of Science, and Cochrane, were searched for key terms published in peer-reviewed journals until January 2021. The Newcastle-Ottawa scale was used to assess the quality of studies and risk of bias. The primary and residual confounders were explored and evaluated. A meta-analysis synthesizing quantitative data was carried out using a random-effects model. Seventeen clinical studies were identified, including 14 cohort, one cross-sectional, and two case-control studies. Study samples ranged from 85 to 262,349 subjects, with follow-up between 2 and 32 years, and age above 45 years, except for two studies. The findings of studies suggesting the PDS-ACI relationship revealed substantial differences in design and methods. A noticeable variation related to the treatment of confounders was observed. Quality assessment unveiled a moderate quality of evidence and risk of bias. The subgroups meta-analysis and pooled sensitivity analysis of results from seven eligible studies demonstrated overall that the presence of PDS is associated with an increased risk of incidence of cognitive impairment (OR = 1.36, 95% CI 1.03-1.79), particularly dementia (OR = 1.39, 95% CI 1.02-1.88) and Alzheimer's disease (OR = 1.03 95% CI 0.98-1.07)). However, a considerable heterogeneity of synthesized data (I2 = 96%) and potential publication bias might affect obtained results. While there is a moderate statistical association between periodontitis and dementia, as well as Alzheimer's disease, the risk of bias in the evidence prevents conclusions being drawn about the role of periodontitis as a risk factor for age-related cognitive impairment.

Dual-functional composite scaffolds for inhibiting infection and promoting bone regeneration

The treatment of infected bone defects is an intractable problem in orthopedics. It comprises two critical parts, namely that of infection control and bone defect repair. According to these two core tasks during treatment, the ideal approach of simultaneously controlling infection and repairing bone defects is promising treatment strategy. Several engineered biomaterials and drug delivery systems with dual functions of anti-bacterial action and ostogenesis-promotion have been developed and demonstrated excellent therapeutic effects. Compared with the conventional treatment method, the dual-functional composite scaffold can provide one-stage treatment avoiding multiple surgeries, thereby remarkably simplifying the treatment process and reducing the treatment time, overcoming the disadvantages of conventional bone transplantation. In this review, the impaired bone repair ability and its specific mechanisms in the microenvironment of pathogen infection and excessive inflammation were analyzed, providing a theoretical basis for the treatment of infectious bone defects. Furthermore, we discussed the composite dual-functional scaffold composed of a combination of antibacterial and osteogenic material. Finally, a series of advanced drug delivery systems with antibacterial and bone-promoting capabilities were summarized and discussed. This review provides a comprehensive understanding for the microenvironment of infectious bone defects and leading-edge design strategies for the antibacterial and bone-promoting dual-function scaffold, thus providing clinically significant treatment methods for infectious bone defects.

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Antibacterial and bone-promoting dual-function scaffolds are ideal strategies for treatment of infectious bone defects.

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The effect of infection on bone repair was summarized in detail from four important aspects.

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A variety of dual-function scaffolds based on antibacterial and osteogenic materials were discussed.

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Dual-function drug delivery systems promoting repair of infectious bone defects by locally releasing functional agents.

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Leading-edge design strategies, challenges and prospects for dual-functional biomaterials were provided.

Ultra-small molybdenum-based nanodots as an antioxidant platform for effective treatment of periodontal disease

Periodontal disease (PD) is a local inflammatory disease with high morbidity, manifesting tissue destruction results from inflammation of the host immune response to bacterial antigens and irritants. The supportive function of connective tissue and skeletal tissue can be jeopardized without prompt and effective intervention, representing the major cause of tooth loss. However, traditional treatments exhibited great limitations, such as low efficacies, causing serious side effects and recurrent inflammatory episodes. As a major defense mechanism, reactive oxygen species (ROS) play important roles in the pathological progression of PD. Antioxidant therapy is widely believed to be an effective strategy for ROS-triggered diseases, including oxidative stress-induced PD. Most antioxidants can only scavenge one or a few limited kinds of ROS and cannot handle all kinds. In addition, current antioxidant nanomaterials present limitations associated with toxicity, low stability, and poor biocompatibility. To this end, we develop ultra-small molybdenum-based nanodots (MoNDs) with strong ROS in oxidative stress-induced PD. To the best of our knowledge, this is the first time that MoNDs have been used for PD. In the present study, MoNDs have shown extremely good therapeutic effects as ROS scavengers. Spectroscopic and in vitro experiments provided strong evidence for the roles of MoNDs in eliminating multiple ROS and inhibiting ROS-induced inflammatory responses. In addition, the mouse model of PD was established and demonstrated the feasibility of MoNDs as powerful antioxidants. It can alleviate periodontal inflammation by scavenging multiple ROS without obvious side effects and exhibit good biocompatibility. Thus, this newly developed nanomedicine is effective in scavenging ROS and inhibiting M1 phenotypic polarization, which provides promising candidates for the treatment of PD.

Concise Total Synthesis of (+)-Lanceolactone A: Revision of Absolute Stereochemistry

A chiral-pool protecting-group-free five-step total synthesis of tetranorsesquiterpenoide (+)-lanceolactone A and all of its four stereoisomers using (S)-(+)-, and (R)-(-)-linalool (coriandrol) as building blocks is disclosed. The key steps involved in this synthetic route are regioselective ozonolysis, Au(I)-catalyzed cycloisomerization-induced construction of furan from alleneone, and dye-sensitized photo-oxidation (through ¹O₂; singlet oxygen) of hydroxyalkyl-tethered furan to access oxaspirolactone. After a thorough evaluation of electronic circular dichroism (ECD) and optical rotation data of all possible stereoisomers, the absolute configuration of natural lanceolactone A at the C4 and C7 positions has been assigned as (+)-(4S,7S), which is an enantiomer to the initially proposed structure (+)-(4R,7R). Further, these investigations led us to extend Feringa and Gawronski's CD correlation method to [5,5]- and [6,5]-oxaspirolactones.

Biological Activity of Copaiba in Damage to the Alveolar Bone in a Model of Periodontitis Induced in Rats

Several studies have investigated the effects of natural products in the treatment of diseases. Traditional Amazonian populations commonly use copaiba due to its well-known anti-inflammatory, antibacterial, and healing properties. In this study, we aimed to investigate the effects of systemic administration of copaiba oleoresin (Copaifera reticulata Ducke) on ligature-induced periodontitis in rats. To do so, 21 adult rats were divided into three groups (n = 7 each): a control group, ligature-induced periodontitis group, and ligature-induced periodontitis group treated with copaiba oleoresin (200 mg/kg/day). The ligature remained from day 0 to 14, and the copaiba oleoresin was administered via oral gavage during the last seven days. On day 14, the animals were euthanized, and mandibles were collected for histopathological evaluation and microcomputed tomography analysis. Our data showed that the administration of copaiba considerably reduced the inflammatory profile. Moreover, copaiba oleoresin limited alveolar bone loss, increased trabecular thickness and bone-to-tissue volume ratio, and decreased the number of trabeculae compared with those of the untreated experimental periodontitis group. Our findings provide pioneering evidence that supports the potential of copaiba oleoresin in reducing periodontitis-induced alveolar bone damage in rats.

Effects of Periodontal Treatment on Levels of Proinflammatory Cytokines in Patients with Chronic Periodontitis: A Meta-Analysis

Background

During the progression of chronic periodontitis (CP), changes in the levels of inflammatory factors are detected in serum and gingival sulcus fluid (GCF). The aim of this meta-analysis was to systematically evaluate the effect of periodontal treatment on GCF and serum proinflammatory cytokines (IL-6, TNF-α, and IL-8) in patients with CP.

Methods

Literature searches were performed through PubMed, Web of Science, Embase, China National Knowledge Infrastructure (CNKI), and Wanfang Database. Randomized controlled trials comparing cytokine levels in periodontal treatment (experimental group) and control group between 2015 and 2020 were included.

Results

There were a total of 13 studies included with 1220 patients. There were 630 cases in the experimental group and 590 cases in the control group. The meta-analysis showed that IL-6 levels in the GCF (SMD = −2.88, 95% CI (-3.68, -2.09), P < 0.001) and serum (SMD = −1.27, 95% CI (-1.72, -0.81), P < 0.001) were significantly lower in the experimental group compared with those before treatment. In addition, IL-8 levels in the GCF (SMD = −2.08, 95% CI (-3.40, -0.76), P < 0.001) and serum (SMD = −1.73, 95% CI (-2.76, -0.70), P < 0.001) were decreased after periodontal treatment, but more than that, a decrease was observed in TNF-α levels of GCF (SMD = −3.98, 95% CI (-5.23, -2.73), P < 0.001) and serum (SMD = −1.80, 95% CI (-3.16, -0.45), P < 0.001) after treatment.

Conclusion

After periodontal therapy, the proinflammatory cytokines in the GCF and serum of patients with CP were significantly decreased compared with those before treatment, and the efficacy was remarkable.

Sec-O-Glucosylhamaudol Inhibits RANKL-Induced Osteoclastogenesis by Repressing 5-LO and AKT/GSK3β Signaling

Sec-O-glucosylhamaudol (SOG), an active flavonoid compound derived from the root of Saposhnikovia divaricata (Turcz. ex Ledeb.) Schischk., exhibits analgesic, anti-inflammatory, and high 5-lipoxygenase (5-LO) inhibitory effects. However, its effect on osteoclastogenesis was unclear. We demonstrated that SOG markedly attenuated RANKL-induced osteoclast formation, F-actin ring formation, and mineral resorption by reducing the induction of key transcription factors NFATc1, c-Fos, and their target genes such as TRAP, CTSK, and DC-STAMP during osteoclastogenesis. Western blotting showed that SOG significantly inhibited the phosphorylation of AKT and GSK3β at the middle–late stage of osteoclastogenesis without altering calcineurin catalytic subunit protein phosphatase-2β-Aα expression. Moreover, GSK3β inhibitor SB415286 partially reversed SOG-induced inhibition of osteoclastogenesis, suggesting that SOG inhibits RANKL-induced osteoclastogenesis by activating GSK3β, at least in part. 5-LO gene silencing by small interfering RNA in mouse bone marrow macrophages markedly reduced RANKL-induced osteoclastogenesis by inhibiting NFATc1. However, it did not affect the phosphorylation of AKT or GSK3β, indicating that SOG exerts its inhibitory effects on osteoclastogenesis by suppressing both the independent 5-LO pathway and AKT-mediated GSK3β inactivation. In support of this, SOG significantly improved bone destruction in a lipopolysaccharide-induced mouse model of bone loss. Taken together, these results suggest a potential therapeutic effect for SOG on osteoclast-related bone lysis disease.

Specific inflammatory osteoclast precursors induced during chronic inflammation give rise to highly active osteoclasts associated with inflammatory bone loss

Elevated osteoclast (OC) activity is a major contributor to inflammatory bone loss (IBL) during chronic inflammatory diseases. However, the specific OC precursors (OCPs) responding to inflammatory cues and the underlying mechanisms leading to IBL are poorly understood. We identified two distinct OCP subsets: Ly6C^hiCD11b^hi inflammatory OCPs (iOCPs) induced during chronic inflammation, and homeostatic Ly6C^hiCD11b^lo OCPs (hOCPs) which remained unchanged. Functional and proteomic characterization revealed that while iOCPs were rare and displayed low osteoclastogenic potential under normal conditions, they expanded during chronic inflammation and generated OCs with enhanced activity. In contrast, hOCPs were abundant and manifested high osteoclastogenic potential under normal conditions but generated OCs with low activity and were unresponsive to the inflammatory environment. Osteoclasts derived from iOCPs expressed higher levels of resorptive and metabolic proteins than those generated from hOCPs, highlighting that different osteoclast populations are formed by distinct precursors. We further identified the TNF-α and S100A8/A9 proteins as key regulators that control the iOCP response during chronic inflammation. Furthermore, we demonstrated that the response of iOCPs but not that of hOCPs was abrogated in tnf-α^-/- mice, in correlation with attenuated IBL. Our findings suggest a central role for iOCPs in IBL induction. iOCPs can serve as potential biomarkers for IBL detection and possibly as new therapeutic targets to combat IBL in a wide range of inflammatory conditions.

Association of the Unstimulated Whole Salivary Cytokine IL-1β Levels with Initial, Moderate and Severe Periodontitis. A Case Control Study

Periodontitis (P) is a highly prevalent inflammatory disease of the oral cavity. The objective of the study was to evaluate the stages of pro-inflammatory cytokine IL-1β in initial, moderate and severe periodontitis. One hundred and twenty two patients were included in the study. Periodontitis subjects had at least 20 natural teeth and ≥8 sites with pocket depths of >4 mm and clinical attachment loss (CAL). A questionnaire was used with respect to the socio demographic parameters which included age, gender, ethnicity, education, marital, residence and occupation. To categorize the severity of the disease, teeth were assessed for, Plaque index (PI), Bleeding on probing (BOP), CAL, missing tooth, tooth mobility and bone loss. Unstimulated whole saliva (UWS) was collected and Interleukin-1β (IL-1β) cytokine levels were analyzed using enzyme linked immunosorbent assay with microplate reader at 450 nm. Clinical parameters and salivary cytokine concentrations were assessed using one-way analysis of variance, whereas a correlation of cases with gender and severity of periodontitis was evaluated using chi-square test. Fifty-nine patients were healthy controls and 63 were periodontitis patients Thirty two percent (n = 20) had initial periodontitis, 40% (n = 25) suffered from moderate and 29% (n = 18) had severe periodontitis. Periodontitis subgroups were significantly different with regards to age and gender (p < 0.001). The mean PPD and CAL among the periodontitis patients (PPD, 3.52 ± 1.25 mm; CAL, 4.04 ± 1.64 mm) were significantly compromised (p < 0.05) compared to healthy controls (PPD, 1.52 ± 0.73 mm; CAL, 0.08 ± 0.28 mm). Increased levels of IL-1β were associated with high CAL and PPD findings. UWS IL-1β levels were higher in periodontitis patients compared to healthy individuals. In addition, cases of severe periodontitis showed significantly higher UWS IL-1β levels compared to initial and moderate periodontitis patients. Comparative levels of salivary IL-1β can be potentially used as a diagnostic tool for periodontitis identification and disease progression along with clinical parameters.

Eriodictyol Suppresses Porphyromonas gingivalis-Induced Reactive Oxygen Species Production by Gingival Keratinocytes and the Inflammatory Response of Macrophages

Porphyromonas gingivalis is a key pathogen of periodontitis, an inflammatory disease that affects the tooth-supporting tissues. The aim of the present study was to investigate the effects of the flavanone eriodictyol on P. gingivalis-induced reactive oxygen species (ROS) production by gingival keratinocytes and the inflammatory response of macrophages. Porphyromonas gingivalis and H2O2 acted synergistically to induce ROS production by keratinocytes. The presence of eriodictyol significantly attenuated ROS production in a dose-dependent manner. We used a macrophage model to show that eriodictyol decreases the secretion of IL-1β, IL-6, IL-8, and TNF-α induced by P. gingivalis. Evidence has been brought that this anti-inflammatory property of eriodictyol may be related to its ability to prevent the activation of the NF-κB signaling pathway by P. gingivalis. This periodontal pathogen was also found to be a potent inducer of matrix metalloproteinase (MMP) production by macrophages, including MMP-2, MMP-8, and MMP-9. Eriodictyol dose-dependently inhibited the production of all three MMPs. Lastly, eriodictyol inhibited the catalytic activity of both MMP-9 and P. gingivalis collagenase. In conclusion, eriodictyol may be a potential therapeutic agent for preventing and/or treating periodontal disease due to its antioxidant, anti-inflammatory, and anti-proteinase properties.

Implication of thyroid function in periodontitis: a nationwide population-based study

Possible links between periodontitis and various cardiometabolic and autoimmune diseases have been advocated on the basis of chronic inflammation or oxidative stress. However, the association between periodontitis and thyroid dysfunction is under-researched. Participants without previous thyroid disease or ongoing thyroid-related medication were included from a nationwide population-level survey. Participants were categorized into tertiles of thyroid stimulating hormone (TSH) levels (first tertile < 1.76 mIU/L; second tertile 1.76-2.83 mIU/L; third tertile > 2.83 mIU/L), and periodontal condition was assessed using the Community Periodontal Index. Of the total of 5468 participants, 1423 had periodontitis (26%). A significant difference in the weighted prevalence of periodontitis according to TSH tertiles was observed, with the highest prevalence in the first tertile (26.5%) and the lowest prevalence in the third tertile (20.9%, p = 0.003). Subjects in the first TSH tertile had higher odds for periodontitis than those in the third tertile (OR 1.36, 95% CI 1.10-1.68; p for trend = 0.005) after adjusting for covariates. This association was consistent across subgroups and within sensitivity analyses among subjects without specific factors affecting thyroid function or diseases reported to be related to periodontitis. The present study demonstrated that low TSH levels were associated with significantly higher odds for periodontitis.

Influence of Gestational Hormones on the Bacteria-Induced Cytokine Response in Periodontitis

Periodontitis is an inflammatory disease that affects the supporting structures of teeth. The presence of a bacterial biofilm initiates a destructive inflammatory process orchestrated by various inflammatory mediators, most notably proinflammatory cytokines, which are upregulated in the gingival crevicular fluid, leading to the formation of periodontal pockets. This represents a well-characterized microbial change during the transition from periodontal health to periodontitis; interestingly, the gestational condition increases the risk and severity of periodontal disease. Although the influence of periodontitis on pregnancy has been extensively reviewed, the relationship between pregnancy and the development/evolution of periodontitis has been little studied compared to the effect of periodontitis on adverse pregnancy outcomes. This review is aimed at summarizing the findings on the pregnancy-proinflammatory cytokine relationship and discussing its possible involvement in the development of periodontitis. We address (1) an overview of periodontal disease, (2) the immune response and possible involvement of proinflammatory cytokines in the development of periodontitis, (3) how bone tissue remodelling takes place with an emphasis on the involvement of the inflammatory response and metalloproteinases during periodontitis, and (4) the influence of hormonal profile during pregnancy on the development of periodontitis. Finally, we believe this review may be helpful for designing immunotherapies based on the stage of pregnancy to control the severity and pathology of periodontal disease.

The -592C>A Variation of IL-10 Gene and Susceptibility to Chronic Periodontitis: A Genetic Association Study and In-Silico Analysis

OBJECTIVES

Chronic periodontitis (CP) is a common inflammatory disorder with a considerable impact of genetic variations in the interleukin family on predisposition to this disease. This study aimed to investigate the association between the -592C>A polymorphism of the interleukin 10 (IL-10) gene with CP risk in an Iranian population. This experimental study was followed by a meta-analysis and in silico examination.

METHODS

In a case-control study, 270 subjects, including 135 patients with CP and 135 healthy controls, were enrolled. The -592C>A genotyping was performed using the PCR-RFLP method. In the meta-analysis, valid databases were systematically searched to identify relevant studies. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were computed to examine the association between -592C>A and CP. In silico analysis was conducted using bioinformatics tools to evaluate the impact of the -592C>A polymorphism on IL-10 gene function.

RESULTS

Our case-control study revealed a significant association between polymorphism and CP risk. Overall, we found significant associations between -592C>A genetic variation and CP and stratified meta-analysis. In silico analysis revealed that this polymorphism could change the pattern of the transcription binding site upstream of the IL-10 gene. It may also alter the hsa-miR-101-3p miRNA-targeted sequence upstream of IL-10.

CONCLUSIONS

Based on our results, the -592C>A variation in IL-10 may be a genetic risk factor for susceptibility to chronic periodontitis. However, further studies in different ethnicities and results adjusted for clinical and demographic characteristics are needed to obtain more accurate deductions.

The Potential Role of RP105 in Regulation of Inflammation and Osteoclastogenesis During Inflammatory Diseases

Inflammatory diseases have a negative impact on bone homeostasis via exacerbated local and systemic inflammation. Bone resorbing osteoclasts are mainly derived from hematopoietic precursors and bone marrow monocytes. Induced osteoclastogenesis during inflammation, autoimmunity, metabolic diseases, and cancers is associated with bone loss and osteoporosis. Proinflammatory cytokines, pathogen-associated molecular patterns, or endogenous pathogenic factors induce osteoclastogenic differentiation by binding to the Toll-like receptor (TLR) family expressed on surface of osteoclast precursors. As a non-canonical member of the TLRs, radioprotective 105 kDa (RP105 or CD180) and its ligand, myeloid differentiation protein 1 (MD1), are involved in several bone metabolic disorders. Reports from literature had demonstrated RP105 as an important activator of B cells, bone marrow monocytes, and macrophages, which regulates inflammatory cytokines release from immune cells. Reports from literature had shown the association between RP105 and other TLRs, and the downstream signaling mechanisms of RP105 with different “signaling-competent” partners in immune cells during different disease conditions. This review is focused to summarize: (1) the role of RP105 on immune cells’ function and inflammation regulation (2) the potential regulatory roles of RP105 in different disease-mediated osteoclast activation and the underlying mechanisms, and (3) the different “signaling-competent” partners of RP105 that regulates osteoclastogenesis.

Phytocystatin CsinCPI-2 Reduces Osteoclastogenesis and Alveolar Bone Loss

Periodontal disease (PD) is a polymicrobial chronic inflammatory condition of the supporting tissues around the teeth, leading to the destruction of surrounding connective tissue. During the progression of PD, osteoclasts play a crucial role in the resorption of alveolar bone that eventually leads to the loss of teeth if the PD is left untreated. Therefore, the development of antiresorptive therapies targeting bone-resorbing cells will significantly benefit the treatment of PD. Here, we demonstrate the inhibitory effect of CsinCPI-2, a novel cysteine peptidase inhibitor from the orange tree, on periodontitis-induced inflammation, alveolar bone loss, and osteoclast differentiation. Using the ligature-induced periodontitis model in mice, we show that treatment with CsinCPI-2 (0.8 µg/g of body weight) significantly reduced inflammatory cell infiltrate in the connective tissue and prevented the loss of alveolar bone mass (BV/TV) caused by PD, effects associated with diminished numbers of TRAP-positive multinucleated cells. Furthermore, CsinCPI-2 significantly downregulated the numbers of inflammatory cells expressing CD3, CD45, MAC387, and IL-1β. In vitro, CsinCPI-2 inhibited RANKL-induced TRAP+ multinucleated osteoclast formation in mouse bone marrow macrophage cultures in a concentration-dependent manner. This effect was not due to cytotoxicity, as demonstrated by the MTT assay. CsinCPI-2 inhibited RANKL-induced mRNA expression of Acp5, Calcr, and Ctsk, as well as the RANKL-induced upregulation of Nfatc1, a crucial transcription factor for osteoclast differentiation. Based on our findings, CsinCPI-2 prevents bone loss induced by PD by controlling the inflammatory process and acting directly on osteoclastogenesis, suggesting an interesting potential for CsinCPI-2 in the strategy for PD treatment.

Osteogenic Differentiation of Mesenchymal Stem Cells via Curcumin-Containing Nanoscaffolds

The diverse pleiotropic pharmacological effects of curcumin nanoformulations have turned it into an attractive natural compound in different health-related problems. A great body of evidence has shown the impact of curcumin and its nanoformulations on the differentiation of stem cells. The current review highlights cellular and molecular mechanisms connected with the osteogenic differentiation of mesenchymal stem cells (MSCs) in the scaffolds benefiting from the presence of nanocurcumin pointing toward the role of inhibitory or stimulant signal transduction pathways in detail. Moreover, the effects of different concentrations as well as the structural modifications of curcumin on the differentiation of MSCs have been addressed.

Human gingiva-derived mesenchymal stem cells promote osteogenic differentiation through their immunosuppressive function

OBJECTIVES

Human gingiva-derived mesenchymal stem cells (GMSCs) have emerged as a new MSC population exhibiting robust immune regulatory functions, multipotent differentiation potential, and regenerative ability. However, the effects of GMSCs on T cells remain unexplored. Herein, we aimed to evaluate whether GMSCs promote osteogenic differentiation by regulating immune cells.

METHODS

The GMSC phenotype was confirmed using the colony-forming assay, immunophenotyping, Oil red O staining, and Alizarin red staining. mRNA expression levels of proinflammatory molecules (interleukin-1β [IL-1β] and tumor necrosis factor-α [TNF-α]) and anti-inflammatory factors (IL-10) were measured by quantitative reverse-transcription PCR (qRT-PCR). Then, MC3T3-E1 cells were treated with the collected co-culture supernatant, followed by alkaline phosphatase (ALP) and immunofluorescence staining to evaluate osteogenic differentiation of MC3T3-E1 cells. qRT-PCR and western blotting were employed to analyze the expression levels of osteogenic differentiation proteins, including collagen type I (COL-1), ALP, osteopontin (OPN), and runt-related transcription factor 2 (RUNX2).

RESULTS

GMSCs were successfully isolated and identified. We observed that GMSCs suppressed the activated T-cell function by downregulating IL-1β and TNF-α and upregulating IL-10. Simultaneously, the expression levels of osteogenesis-related genes (COL-1, ALP, OPN, and RUNX2) were markedly lower in the co-culture supernatant and Jurkat T cell supernatant groups than those in the normal culture medium group; however, expression levels were significantly increased in the co-culture supernatant group when compared with the Jurkat T cell supernatant group.

CONCLUSION

Our findings indicate that GMSCs could promote the osteogenic differentiation of MC3T3-E1 cells by inhibiting the biological activity of activated T cells.

Periodontitis in patients with systemic lupus erythematosus: A nation-wide study of 1990 patients

BACKGROUND

The aim of this study was to examine the association between systemic lupus erythematosus (SLE) and periodontitis in Norway during a 10-year period from 2008 through 2017.

METHODS

In this population-based study, 1990 patients were included in the SLE-cohort based on diagnostic codes registered in the Norwegian Patient Registry. The control group (n = 170,332) comprised patients registered with diagnostic codes for non-osteoporotic fractures or hip or knee replacement because of osteoarthritis. The outcome was periodontitis, defined by procedure codes registered in the Control and Payment of Health Refunds database. Logistic regression analyses were performed to estimate odds ratio for periodontitis in patients versus controls adjusted for potential covariates.

RESULTS

Periodontitis was significantly more common in SLE patients compared to controls (OR 1.78, 95% CI 1.47-2.14) and the difference was highest in SLE-patients 20 to 30 years of age (OR 3.24, 95% CI 1.23 - 8.52). The periodontitis rate in SLE patients was in the same range as for patients with diabetes mellitus type 2.

CONCLUSIONS

Patients with SLE had an almost doubled risk of periodontitis compared with the control population, and the difference was most accentuated in the young patients. These findings warrant an increased focus on dental health in SLE-patients.

Fermented milk with Lactobacillus curvatus SMFM2016-NK alleviates periodontal and gut inflammation, and alters oral and gut microbiota

This study aimed to analyze the effect of milk fermented with Lactobacillus curvatus SMFM2016-NK on periodontal diseases and gut health in a rat model. To improve the effect of Lb. curvatus SMFM2016-NK-fermented milk administration for relieving periodontitis, the periodontitis rat models were treated with the following for 4 wk: 10% skim milk (normal), periodontitis + 10% skim milk (negative control), periodontitis + Lactobacillus rhamnosus GG-fermented milk (positive control), and periodontitis + Lb. curvatus SMFM2016-NK-fermented milk (PD+LCFM). Transcriptional analysis of inflammatory cytokines [tumor necrosis factor α (TNF-α), IL-1β, IL-6, and IL-10] was performed via quantitative reverse-transcription PCR. The changes in the oral and gut microbiomes after administering Lb. curvatus SMFM2016-NK-fermented milk were analyzed with metagenomics sequencing using DNA extracted from the oral gingival tissues and feces from the cecum of the rat models. After treatment with Lb. curvatus SMFM2016-NK-fermented milk, the relative gene expression levels of TNFA and IL1B in the gingiva decreased in the PD+LCFM group compared with those in the negative control group. In the oral microbiome, the proportion of the phylum Proteobacteria in the PD+LCFM group was lower than that in the negative control after treatment with Lb. curvatus SMFM2016-NK-fermented milk. For the effect in the gut, the relative gene expression levels of inflammatory cytokines in the colon between the normal and negative control groups were not different; however, the expression levels of TNFA and IL1B in the PD+LCFM and positive control groups, respectively, were lower than those in the negative control group. The composition and diversity of the gut microbiome differed among normal, periodontitis, and Lb. curvatus SMFM2016-NK-fermented milk treatment groups. These results indicate that Lb. curvatus SMFM2016-NK-fermented milk could alleviate periodontal and gut inflammation and change oral and gut microbiota.

Assessment of salivary pro inflammatory cytokines profile level in patients treated with labial and lingual fixed orthodontic appliances

The secretions of certain cytokines, chemokines and growth factors are triggered by orthodontic appliances, which often affect the remodelling of periodontal tissues. Critical cumulative forces are applied by various types of orthodontic appliances to the periodontium. The secretion of such molecules is probably responsible, through molecular and cellular communications, for the optimal resorption of hard tissues in the periodontal setting, which therefore enables the coordination of multiple movements of tooth. This study assessed and compared a wide range of cytokines, cellular marker analysis and defensins present in the saliva samples of human subjected to orthodontic treatment with two different treatment modalities, i.e., conventional lingual and labial fixed orthodontic appliances. A total 40 samples of saliva were obtained, of which 20 were treated with traditional lingual appliances and 20 were treated with labial fixed appliances. After 21 days of treatment, all salivary samples were collected from the subjects. In order to analyse a broad range of soluble cytokine levels in saliva by flow cytometry, a bead-based immunoassay was performed. Cell surface markers were analysed by flow cytometry. Protein levels of saliva for defensins were quantified by ELISA. Non-significant differences were observed in the cytokine levels in the saliva except for the significant effects for CCL2, IL-17A and IL-6. Cellular markers CD45 and CD326 showed high percentage in conventional lingual samples. Defensin levels were found to be lower in conventional lingual patients. Subjects with conventional lingual appliances had significantly higher salivary protein levels of IL-1β, CCL2, IL17A, and IL-6, higher CD45+ and CD326+ cells and lower defensin levels than subjects with fixed labial appliances. The current study provided a clear basis for the development of innovative methods to aid in the improvement of various procedural treatments and orthodontic equipment of next generation.

IL-8 as a Potential Therapeutic Target for Periodontitis and Its Inhibition by Caffeic Acid Phenethyl Ester In Vitro

Salivary levels of interleukin-8 (IL-8) are elevated in patients with periodontitis. Caffeic acid phenethyl ester (CAPE) improves the periodontal status in subjects. However, whether CAPE can reduce IL-8 expression is unclear. We collected saliva to determine proinflammatory cytokine levels and used subgingival calculus and surrounding tissues from patients with periodontitis for oral microbiota analysis via 16s ribosomal RNA gene sequencing. THP-1 cells were stimulated with sterile-filtered saliva from patients, and target gene/protein expression was assessed. IL-8 mRNA expression was analyzed in saliva-stimulated THP-1 cells treated with CAPE and the heme oxygenase-1 (HO-1) inhibitor tin-protoporphyrin (SnPP). In 72 symptomatic individuals, IL-8 was correlated with periodontal inflammation (bleeding on probing, r = 0.45; p < 0.001) and disease severity (bleeding on probing, r = 0.45; p < 0.001) but not with the four oral microbiota species tested. Reduced salivary IL-8 secretion was correlated with effective periodontitis treatment (r = 0.37, p = 0.0013). In THP-1 cells, saliva treatment induced high IL-8 expression and IKK2 and nuclear factor-κB (NF-κB) phosphorylation. However, the IKK inhibitor BMS-345541, NF-κB inhibitor BAY 11-7082, and CAPE attenuated saliva-induced IL-8 expression. CAPE induced HO-1 expression and inhibited IKK2, IκBα, and NF-κB phosphorylation. Blocking HO-1 decreased the anti-inflammatory activity of CAPE. The targeted suppression of IL-8 production using CAPE reduces inflammation and periodontitis.

Maintaining homeostatic control of periodontal bone tissue

Alveolar bone is a unique osseous tissue due to the proximity of dental plaque biofilms. Periodontal health and homeostasis are mediated by a balanced host immune response to these polymicrobial biofilms. Dysbiotic shifts within dental plaque biofilms can drive a proinflammatory immune response state in the periodontal epithelial and gingival connective tissues, which leads to paracrine signaling to subjacent bone cells. Sustained chronic periodontal inflammation disrupts "coupled" osteoclast-osteoblast actions, which ultimately result in alveolar bone destruction. This chapter will provide an overview of alveolar bone physiology and will highlight why the oral microbiota is a critical regulator of alveolar bone remodeling. The ecology of dental plaque biofilms will be discussed in the context that periodontitis is a polymicrobial disruption of host homeostasis. The pathogenesis of periodontal bone loss will be explained from both a historical and current perspective, providing the opportunity to revisit the role of fibrosis in alveolar bone destruction. Periodontal immune cell interactions with bone cells will be reviewed based on our current understanding of osteoimmunological mechanisms influencing alveolar bone remodeling. Lastly, probiotic and prebiotic interventions in the oral microbiota will be evaluated as potential noninvasive therapies to support alveolar bone homeostasis and prevent periodontal bone loss.

Pro-inflammatory cytokine interleukin-6-induced hepcidin, a key mediator of periodontitis-related anemia of inflammation

OBJECTIVES

To investigate whether anemia of inflammation (AI) occurs in periodontitis patients and to further explore underlying pathogenesis of periodontitis-related AI by an experimental periodontitis model.

BACKGROUND

Previous studies have reported periodontitis patients could show a tendency toward AI. However, the relationship between periodontitis and AI remains unclear, and the related pathological mechanisms have not been identified.

MATERIALS AND METHODS

Periodontal clinical parameters, inflammatory markers, and anemia-related indicators were compared between 98 aggressive periodontitis (AgP) patients and 103 healthy subjects. An experimental periodontitis model was induced by ligature placement in mice. The changes in mice inflammatory markers, anemia indicators, hepcidin mRNA expression, and serum hepcidin concentrations were measured. Human and mouse liver cells were treated with interleukin-6 (IL-6) for analyzing the changes in hepcidin expression based on mRNA and protein levels.

RESULTS

AgP patients exhibited higher white blood cell counts, IL-6, and C-reactive protein. Adjusted linear regression analyses showed correlations between AgP and decreased hemoglobin (HGB) and hematocrit (HCT). The ligature-induced periodontitis caused systemic inflammation and elevated IL-6 levels. Lower red blood cell counts, HGB, and HCT were detected, whereas the levels of hepcidin mRNA expression and serum hepcidin concentrations increased. The treatment of hepatocytes with IL-6 induced both hepcidin mRNA expression and hepcidin secretion.

CONCLUSIONS

Systemic inflammation induced by periodontitis leads to an increased risk for AI. IL-6-induced hepcidin could play a central mediator role and act as a key pathologic mechanism. Our results demonstrate periodontitis may be considered as an additional inflammatory disease contributing to the development of AI.

Metabolic syndrome and severe periodontitis were associated in Thai adults: A cross-sectional study

BACKGROUND

Studies support the relationship between metabolic syndrome (MetS) and periodontitis. However, age is the major confounding factor for both conditions. Therefore, this cross-sectional study was performed to investigate the relationship between MetS and severe periodontitis in different Thai adult age groups.

METHODS

Data on the medical history, medical examination, and full mouth oral examination of 5,690 Electricity Generating Authority of Thailand employees aged 25 to 77 years were collected. The prevalence ratio (PR) between risk variables, MetS, and periodontitis was determined using Poisson regression analysis. Moreover, the subgroup analysis and effect modification by age on severe periodontitis were performed.

RESULTS

Overall, MetS was significantly associated with severe periodontitis compared with non-severe periodontitis (adjusted PR, 1.11; 95% confidence interval [CI], 1.01 to 1.13). The association was modified by age, with negative effect modification observed on the multiplicative and additive scales. The subgroup analysis revealed a significant relationship between MetS and severe periodontitis only in participants aged <45 years with an adjusted PR of 1.69 (95% CI, 1.29 to 2.21). All MetS components, except hypertension, were associated with severe periodontitis in this group.

CONCLUSIONS

There is a significant relationship between MetS and severe periodontitis in adults aged <45 years. Therefore, attempts to control the risk of MetS and periodontitis should be emphasized for early adults to reduce the incidence of these conditions and related complications when they become elderly.

Intergenerational effects of pre-pregnancy chronic lipopolysaccharide from Porphyromonas gingivalis on the learning, memory and seizure susceptibility of offspring

OBJECTIVE

The aim of this study was to investigate the effects of pre-pregnancy chronic exposure to Porphyromonas gingivalis LPS (Pg LPS) on the learning, memory, and seizure susceptibility of the offspring.

DESIGN

To achieve periodontitis, Pg LPS (5 μg/kg) was injected into the gingival of five female rats every 48 h for three weeks. Five control female rats received saline (0.9 %) and five female were kept intact. The concentrations of TNF-α and IL-6 were measured in the blood samples. One week after the final injection, females were mated with intact males. Following birth and weaning, two male and two female offspring were randomly selected from each mother, and new groups of male and female offspring were defined for behavioral assessments. Morris water maze was used to evaluate spatial memory, shuttle box was used to investigate avoidance memory and a pentylenetetrazole-induced seizure was used to evaluate seizure susceptibility in the offspring.

RESULTS

Spatial learning and avoidance memory significantly decreased in both male and female offspring of Pg LPS-exposed female rats, compared to the control offspring. Latency to reach seizure stages 1 and 2 significantly increased in the male offspring, but not the female offspring of Pg LPS-exposed female, compared to the control offspring. However, no significant difference was found in latency to reach stages 3-5.

CONCLUSION

Pre-pregnancy exposure to Pg LPS could affect some behavioral functions in both male and female offspring intergenerationally.

A polyphenolic cinnamon fraction exhibits anti-inflammatory properties in a monocyte/macrophage model

Periodontal diseases are bacteria-induced inflammatory disorders that lead to the destruction of the tooth-supporting tissues. Active compounds endowed with a capacity to regulate the inflammatory response are regarded as potential therapeutic agents for the treatment of periodontal diseases. The aim of this study was to characterize the anti-inflammatory properties of a polyphenolic cinnamon fraction. Chromatographic and mass spectrometry analyses of the polyphenolic composition of the cinnamon fraction revealed that phenolic acids, flavonoids (flavonols, anthocyanins, flavan-3-ols), and procyanidins make up 9.22%, 0.72%, and 10.63% of the cinnamon fraction, respectively. We used a macrophage model stimulated with lipopolysaccharides (LPS) from either Aggregatibacter actinomycetemcomitans or Escherichia coli to show that the cinnamon fraction dose-dependently reduced IL-6, IL-8, and TNF-α secretion. Evidence was brought that this inhibition of cytokine secretion may result from the ability of the fraction to prevent LPS-induced NF-κB activation. We also showed that the cinnamon fraction reduces LPS binding to monocytes, which may contribute to its anti-inflammatory properties. Lastly, using a competitor assay, it was found that the cinnamon fraction may represent a natural PPAR-γ ligand. Within the limitations of this in vitro study, the cinnamon fraction was shown to exhibit a therapeutic potential for the treatment of periodontal diseases due to its anti-inflammatory properties.

Effect of Pistacia atlantica subsp. kurdica Gum in Experimental Periodontitis Induced in Wistar Rats by Utilization of Osteoclastogenic Bone Markers

The aim of this study was to assess the effect of local application of essential oil of Pistacia atlantica kurdica (EOK) gel in treatment of experimentally induced periodontitis in rats and its effect on osteoclastogenic bone markers. Twenty-four male Wistar rats of 250 to 350 g were used in this study and were allocated into four groups. Control negative (without induced periodontitis), control positive (induced experimental periodontitis left without treatment), treatment control (induced experimental periodontitis and treated with Chlorhexidine gel) and EOK treated group (induced experimental periodontitis treated with EOK gel). The animals were sacrificed after 30 days, and the mandibular central incisor and surrounding tissue were dissected from the mandible and further processed for preparing H&E slides. Inflammatory cells, osteoclast cells, and periodontal ligament (PDL) were examined and measured histologically. Finally, the mean concentrations of both markers, receptor activator of nuclear factor kappa-Β ligand (RANKL) and (Interleukin-1β) IL-1β, were analyzed by ELISA. A significant reduction of inflammatory reaction and osteoclast numbers with improvement of PDL and low mean concentrations of RANKL and IL-1β were seen in the EOK treated group in comparison to the control group and the chlorhexidine group as well. The extract showed a protective effect in the healing of periodontitis that had been induced in rats and decreased bone resorption by down regulation of serum RANKL and IL-1β markers.

Effects of vitamin C local application on ligature-induced periodontitis in diabetic rats

Objective:

This study evaluated the effects of local vitamin C treatment on tissue advanced glycation end products (AGE), interleukin (IL)-6, 8-hydroxy-2-deoxyguanosine (8-OHdG), and matrix metalloproteinases (MMP)-8 in tissues; serum C-terminal telopeptide fragments (CTX); and alveolar bone loss (ABL) in rats.

Methodology:

35 male Sprague Dawley rats were divided equally into five groups: 1) control (C), 2) experimental periodontitis (P), 3) experimental diabetes (D), 4) experimental diabetes and experimental periodontitis (D + P), and 5) experimental diabetes–experimental periodontitis–locally applied vitamin C (D + P + LvitC). Diabetes was induced in rats with alloxan monohydrate, after which periodontitis was induced by ligature placement in the right mandibular first molar teeth for 11 days. In the treatment group, vitamin C was administered locally three times with two-days interval after ligature removal. The animals were sacrificed, and the samples were analyzed histometrically and immunohistochemically.

Results:

CTX, 8-OHdG, and AGE values significantly decreased in the treatment group compared to the D + P group. IL-6 and MMP-8 values decreased in the treatment group compared to the D + P group, but this is not significant. ABL was significantly reduced by the local delivery of vitamin C.

Conclusion:

This study reveals that vitamin C treatment may be beneficial to reduce serum CTX and gingival MMP-8 levels, oxidative stress, inflammation, and AGE accumulation in periodontal tissue. Vitamin C may be an immunomodulator and antioxidant locally applied in the treatment of periodontitis to reduce the adverse effects of diabetes in periodontal tissues.

Induced Experimental Periimplantitis and Periodontitis: What are the Differences in the Inflammatory Response ?

This preliminary study investigates the differences between experimental periodontitis and periimplantitis in a dog model, with a focus on the histopathology, the inflammatory responses and specific immunoregulatory activities, driven by Th1/Th2 positive cells. Twelve dental implants were inserted into the edentulated posterior mandibles of six Beagle dogs and were given twelve weeks time for osseointegration. Experimental periimplantitis and periodontitis (first mandible molar) was then induced using cotton-floss ligatures. Twelve weeks later, alveolar bones were quantitated by cone beam-computer tomography. Histopathological analysis of the inflamed gingiva and of the periodontal tissues was performed by light microscopy, and the Th1/ Th2 cell populations were investigated by flow cytometry. Periimplantitis as well as periodontitis were both found to be associated with pronounced bone resorption effects, both to a similar degree vertically, but with a differential bone resorption pattern mesio-distally, and with a significantly higher and consistent bone resorption result in periimplantitis; however, with a higher variance of bone resorption in periodontitis. The histological appearances of the inflammatory tissues were identical. The percentages of Th1/ Th2 cells in the inflamed gingival tissues of both experimental periimplantitis and periodontitis were also found to be similar. Experimental periodontitis and periimplantitis in the dog model show essentially the same cellular pathology of inflammation. However, bone resorption was found to be significantly higher in periimplantitis; the histopathological changes in the periodontal tissues were similar in both groups, but showed a higher inter-individual variation in periodontitis, and appeared more uniform in periimplantitis. This preliminary study indicates that more focused experimental in-vivo inflammation models need to be developed to better simulate the human pathology in the two different diseases, and in order to have a valuable tool to investigate more specifically how novel treatments/prevention approaches may heal the differential adverse effects on bone tissue and on periodontium in periodontitis and in periimplantitis.

A review of T helper 17 cell-related cytokines in serum and saliva in periodontitis

Periodontitis is a chronic inflammatory disease with a complex underlying immunopathology. Cytokines, as molecular mediators of inflammation, play a role in all stages of disease progression. T helper 17 (Th17) cells are thought to play a role in periodontitis. Th17 cell development and maintenance requires a pro-inflammatory cytokine milieu, with many of the cytokines implicated in the pathogenesis of periodontitis. Serum and saliva are easily accessible biofluids which can represent the systemic and local environment to promote the development of Th17 cells. Here we review human clinical studies that investigate IL-1β, IL-4, IL-6, IL-10, IL-17A, IL-17F, IL-21, IL-22, IL-23, IL-25, IL-31, IL-33, IFN-γ, sCD40L and TNF-α in serum and saliva in periodontitis. We highlight their putative role in the pathogenesis of periodontitis and place them within a wider context of animal and other clinical studies.