Cytokine expression in periodontal health and disease

Maintaining a protective state for human periodontal tissue

Periodontitis, caused by infection with periodontal pathogens, is primarily characterized by inflammatory bone resorption and destruction of connective tissue. Simply describing periodontitis as a specific bacterial infection cannot completely explain the various periodontal tissue destruction patterns observed. Periodontal tissue damage is thought to be caused by various factors. In recent years, research goals for periodontal pathogens have shifted from searching for specific pathogens to investigating mechanisms that damage periodontal tissues. Bacteria interact directly with the host in several ways, influencing expression and activity of molecules that evade host defenses, and destroying local tissues and inhibiting their repair. The host's innate and acquired immune systems are important defense mechanisms that protect periodontal tissues from attack and invasion of periodontal pathogens, thus preventing infection. Innate and acquired immunity have evolved to confront the microbial challenge, forming a seamless defense network in periodontal tissues. In the innate immune response, host cells quickly detect, via specialized receptors, macromolecules and nucleic acids present on bacterial cell walls, and this triggers a protective, inflammatory response. The work of this subsystem of host immunity is performed mainly by phagocytes, beta-defensin, and the complement system. In addition, the first line of defense in oral innate immunity is the junctional epithelium, which acts as a physical barrier to the entry of oral bacteria and other nonself substances. In the presence of a normal flora, junctional epithelial cells differentiate actively and proliferate apically, with concomitant increase in chemotactic factor expression recruiting neutrophils. These immune cells play an important role in maintaining homeostasis and the protective state in periodontal tissue because they eliminate unwanted bacteria over time. Previous studies indicate a mechanism for attracting immune cells to periodontal tissue with the purpose of maintaining a protective state; although this mechanism can function without bacteria, it is enhanced by the normal flora. A better understanding of the relationship between the protective state and its disruption in periodontal disease could lead to the development of new treatment strategies for periodontal disease.

The effect of zirconia and titanium surfaces on biofilm formation and on host-derived immunological parameters

The aim of this study was to analyse the effect of zirconia and titanium surfaces on biofilm formation and host-derived parameters. Studies comparing zirconia and titanium surfaces were selected up to September 1, 2019. The outcome measures were surface roughness, contact angle, bacterial count, bacterial adherence, biofilm thickness, bacterial distribution, and specifically investigated biofilm and specific host-derived immunological parameters. Random-effects meta-analyses of in vitro and in vivo studies were conducted. A total of 39 studies were included for data extraction. In the systematic review data, 10 studies stated that zirconia accumulated less initial oral biofilm parameters, 16 investigations showed negligible inter-material differences, and only one study showed that zirconia attracted the most biofilm. However, in the meta-analysis, the bacterial coverage was found to be significantly superior for zirconia surfaces (P< 0.00001); the other outcome measures did not show any statistically significant differences between zirconia and titanium for the remaining parameters and the studies presented a substantial degree of heterogeneity. Overall, on the basis of the meta-analysis, the current data situation does not allow a clear preference for the use of zirconia or titanium.

Mechanisms involved in regulation of periodontal ligament cell production of pro-inflammatory cytokines: Implications in periodontitis

It is well recognized that human periodontal ligament cells (PDL cells) may represent local immune cells of the periodontal tissues. However, it is unclear whether they represent “true” immune cells, since they can produce pro‐inflammatory cytokines not only after stimulation with bacterial lipopolysaccharides but also in response to other stimuli such as mechanical stress. Stimulation with bacterial lipopolysaccharides strongly enhances PDL cell production of pro‐inflammatory cytokines through activation of toll‐like receptors and NF‐κB signaling. Less information is available regarding putative modulators of cytokine production and their mechanisms of action in PDL cells. The anti‐inflammatory glucocorticoid dexamethasone reduces lipopolysaccharide‐induced PDL cell production of cytokines. Recent observations show that vitamin D and the antimicrobial peptide LL‐37 antagonize lipopolysaccharide‐stimulated PDL cell production of pro‐inflammatory cytokines. Secretory leukocyte protease inhibitor is endogenously expressed by PDL cells, and this protein negatively regulates PDL cell‐evoked cytokine production. More information and knowledge about the regulation of PDL cell production of cytokines may clarify the role of PDL cells in oral innate immunity and their importance in periodontitis.

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.

Association between Uremic Toxin Concentrations and Bone Mineral Density after Kidney Transplantation

Although uremic osteoporosis is a component of mineral and bone disorder in chronic kidney disease, uremic toxin (UT) concentrations in patients with end-stage kidney disease and bone mineral density (BMD) changes after kidney transplantation have not previously been described. We hypothesized that elevated UT concentrations at the time of transplantation could have a negative impact on bone during the early post-transplantation period. Hence, we sought to determine whether concentrations of UTs (trimethylamine-N-oxide, indoxylsulfate, p-cresylsulfate, p-cresylglucuronide, indole-3-acetic acid, hippuric acid, and 3-carboxy-4-methyl-5-propyl-furanpropionic acid) upon transplantation are predictive markers for (i) osteoporosis one month after transplantation, and (ii) a BMD decrease and the occurrence of fractures 12 and 24 months after kidney transplantation. Between 2012 and 2018, 310 kidney transplant recipients were included, and dual-energy X-ray absorptiometry was performed 1, 12, and 24 months after transplantation. The UT concentrations upon transplantation were determined by reverse-phase high-performance liquid chromatography. Indoxylsulfate concentrations upon transplantation were positively correlated with BMD one month after transplantation for the femoral neck but were not associated with osteoporosis status upon transplantation. Concentrations of the other UTs upon transplantation were not associated with osteoporosis or BMD one month after transplantation. None of the UT concentrations were associated with BMD changes and the occurrence of osteoporotic fractures 12 and 24 months after transplantation. Hence, UT concentrations at the time of kidney transplantation were not predictive markers of osteoporosis or fractures.

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.

Association between obesity and periodontitis in Australian adults: A single mediation analysis

BACKGROUND

Obesity and periodontitis are conditions with high burden and cost. This study aims to unfold the proposed pathways through which the effect of obesity in the presence of health behaviors (dental visiting behavior and diabetes) increases the risk of periodontitis?

METHODS

The effect decomposition analysis using potential outcome approach was used to determine obesity-related periodontitis risk using the Australian National Survey of Adult Oral Health 2004 to 2006. A single mediation analysis for exposure, "physical-inactivity induced obesity," mediator "dental visiting behavior (a de facto measure of healthy behaviors)," outcome "periodontitis," and confounders "age, sex, household income, level of education, self-reported diabetes, alcohol-intake and smoking," was constructed for subset of 3,715 participants, aged ≥30 years. Proposed pathways were set independently for each risk factor and in synergy. The STATA 15 Paramed library was used for analysis. Sensitivity analysis was conducted to detect unmeasured confounding using non-parametric approach.

RESULTS

The average treatment effect of physical inactivity induced obesity to periodontitis is 14%. Pathway effect analysis using potential outcomes illustrated that the effect of obesity on periodontitis that was not mediated through poor dental visiting behavior was 10%. Indirect effect of obesity-mediated through poor dental visiting behavior on periodontitis was 3%.

CONCLUSIONS

The direct effect of physical inactivity induced obesity on periodontitis was higher than the indirect effect of obesity on periodontitis through dental visiting behavior. Establishing a pathway of causal relationship for obesity and periodontitis could help in developing management strategies that focuses on mediators.

Effect of Orento, a Traditional Japanese Medicine, on IL-6, IL-8 Secretion, Type 1 Collagen Production and Alkaline Phosphatase Secretion in the Human Osteosarcoma Cell Line Saos-2

Background: Orento, a traditional Japanese medicine, is known as Kampo medicine in Japan. We investigated the possible efficacy of Kampo medicine for periodontal disease. In this study, we examined the in vitro effects of orento on the proliferation of the inflammatory cytokines interleukin (IL)-6 and IL-8, the production of type 1 collagen, and the secretion of alkaline phosphatase (ALP) in the human osteosarcoma cell line Saos-2 (Saos-2 cells). Methods: The proliferation of Saos-2 cells was assessed by MTT assay. IL-6 and IL-8 levels, type 1 collagen production and ALP secretion were evaluated using enzyme-linked immunosorbent assay and ALP assays. Saos-2 cells were treated with or without 0.1, 1, 10, 100 and 1000 μg/mL of orento for 24 h. Results: Orento (10 μg/mL) significantly induced the proliferation of Saos-2 cells. At this concentration, orento suppressed IL-6 and IL-8 and enhanced type 1 collagen production and ALP secretion. Conclusions: These results indicate that orento controls the IL-6 and IL-8 secretion and cellular metabolism of osteoblasts, resulting in the secretion of early bone-related biomarkers.

Electronic cigarette liquid substances propylene glycol and vegetable glycerin induce an inflammatory response in gingival epithelial cells

Information on the effects of propylene glycol (PG) and vegetable glycerin (VG) and on cytotoxicity and subsequent activation of the biological mediators is limited in periodontal diseases. This study analyzes the effect of unflavored PG/VG alone or in combination with nicotine on gingival epithelial cells. The cells were exposed to different PG/VG (± nicotine) concentrations for 24 h and cytotoxicity was evaluated by calorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromid assay. The expressions of interleukin (IL)-6, IL-8, and matrix metalloproteinases (MMPs)-9 were measured using an enzyme-linked immunosorbent assay and a western blotting. Stimulation with PG/VG mixtures reduced cell viability compared to nonexposed controls (p < 0.05). Adding PG/VG increased the levels of IL-6, IL-8, and MMP-9, and the amount of PG had more biological impact compared to the VG amount. The nicotine augmented this effect compared to its nicotine-free counterparts. In western blotting result, MMP-9 was clearly activated in almost all samples. These findings suggest that the main constituents PG/VG are cytotoxic and able to induce biological response in gingival cells in vitro. Despite being advertised as less harmful than conventional cigarettes, electronic cigarette liquid pose certain risks on periodontal cells. Awareness about the effects of electronic cigarettes on periodontal diseases must be increased.

T helper 17 cell-related cytokines in serum and saliva during management of periodontitis

AIM

T helper (Th)17 cells are implicated in the pathogenesis of periodontitis. This study investigated the effect of periodontal management on fifteen Th17-related cytokines in serum and saliva in periodontitis patients.

MATERIALS AND METHODS

Periodontal parameters, serum and saliva were collected from 40 healthy controls and 54 periodontitis subjects before treatment, and 3-, 6- and 12-months post-treatment. Cytokine concentrations of 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 were determined by Luminex assay.

RESULTS

IL-1β, IL-6, sCD40L and TNF-α in serum, and IL-1β, IL-6, IL-25 and IL-31 in saliva were significantly higher at baseline compared to health and decreased with treatment. In contrast, serum IL-31 was significantly lower at baseline compared to health and increased with treatment. In addition, salivary IL-10, IL-17A, IL-17F, IL-23, IL-33, IFN-γ and TNF-α also displayed treatment-related reduction. Correlation networks showed that cytokines in saliva displayed a higher number of correlations compared to serum in periodontitis.

CONCLUSION

Treatment generally decreased cytokine concentrations except for serum IL-31 which showed a treatment-related increase. Serum cytokine concentrations may not be reflective of salivary cytokines. Saliva may be a better medium for cytokine detection compared to serum. Serum IL-31 and salivary IL-1β, IL-6, IL-10 and TNF-α were significant predictors for mean probing depth and may be potential biomarkers of interest in the pathogenesis of periodontitis.

IL-1β strengthens the physical barrier in gingival epithelial cells

Periodontitis is one of the most common oral diseases worldwide and is caused by a variety of interactions between oral bacteria and the host. Here, pathogens induce inflammatory host responses that cause the secretion of proinflammatory cytokines such as IL-1β, IL-6, and IL-8 by oral epithelial cells. In various systems, it has been shown that inflammation compromises physical barriers, which enables bacteria to invade the tissue. In this study, we investigated the barrier properties of the oral mucosa under physiological and inflamed conditions. For this purpose, we assessed the influence of IL-1β on the transepithelial electrical resistance and in particular on tight junctions in vitro in human stratified squamous epithelium models. Indirect immunofluorescence and western blot analyses were performed to investigate localization and expression of tight junction proteins in primary gingival cells, immortalized gingival cells and native gingiva. Furthermore, the TEER of gingival keratinocytes was assessed. The results showed that IL-1β led to strengthening of the gingival keratinocyte barrier. This was demonstrated by an increase in TEER, the upregulation of TJ proteins, and an increase in the formation of TJ strands. The IL-1β-mediated upregulation of occludin was prevented by the NF-κB inhibitor BAY 11-7085. These observations provide insights into host responses in the early stages of periodontal disease and offer information about TJ formation in human gingival epithelial cells under physiological and inflammatory conditions. Comprehensive knowledge of the physical barrier during inflammation may help in developing strategies to effectively target the inflammatory barrier to improve the bioavailability of drugs for the treatment of periodontitis.

CD19+ CD24hi CD38hi Regulatory B Cells and Memory B Cells in Periodontitis: Association with Pro-Inflammatory and Anti-Inflammatory Cytokines

Regulatory B cells (Bregs) are unique subpopulations of B cells with immune-regulating or immune-suppressing properties and play a role in peripheral tolerance. Due to the current limitations of human Breg studies among periodontal diseases, in the present study, we tried to analyze the change in circulating Bregs, pro-inflammatory, and anti-inflammatory cytokines in patients with periodontitis. Peripheral blood from 55 patients with stage 2 periodontitis and 20 healthy controls was analyzed using flow cytometry to evaluate the frequency of CD19⁺CD24⁺CD38⁺ Breg cells. ELISA was used to assess the serum levels of the pro-inflammatory cytokines, including interleukins (IL)-1β, IL-6, TNF-α, and anti-inflammatory cytokines including IL-10, IL-35, and TGF-β. Increased proportions of Breg cells were observed in patients with stage 2 periodontitis compared to controls. Serum levels of cytokines were significantly higher in patients with periodontitis compared to controls. A significant positive correlation was observed between the frequencies of Breg cells and IL35 levels, IL10 levels, and TGF-β. In conclusion, our results suggest that the increase in peripheral Breg cells and serum cytokine levels among periodontitis patients seems to be closely associated with disease progression, a possible link between periodontitis, and systemic inflammatory process.

Interleukin IL-1B gene polymorphism in Tunisian patients with chronic hepatitis B infection: Association with replication levels

Approaches based on association studies have proven useful in identifying genetic predictors for many diseases, including susceptibility to chronic hepatitis B. In this study we were interested by the IL-1B genetic variants that have been involved in the immune response and we analyzed their role in the susceptibility to develop chronic hepatitis B in the Tunisian population. IL-1B is a potent proinflammatory cytokine that plays an important role in inflammation of the liver. Polymorphic gene IL-1 (-511, +3954) was analyzed in a total of 476 individuals: 236 patients with chronic hepatitis B from different cities of Tunisia recruited in Pasteur Institute between January 2017 and December 2018 and 240 controls. Genomic DNA was obtained using the standard salting-out method and genotyping was performed by polymerase chain reaction (PCR)-restriction fragment length polymorphism. For -511C>T polymorphism a significant association was found between patients and controls when comparing the genotypic (P = 0.007; χ²  = 9.74 and odds ratio [OR] = 0.60; confidence interval [CI] = 0.41-0.89) and allelic (P = 0.001; χ²  = 10.60) frequencies. When the viral load was taken into account a highly significant difference was found (P = 9 × 10^-4 ; χ²  = 10.89). For +3954C>T polymorphism a significant association was found between patients and controls when comparing genotypic (P = 0.0058; χ²  = 7.60 and OR = 1.67; CI = 1.14-2.46) and allelic (P = 0.0029; χ²  = 8.81) frequencies. T allele can be used as a strong marker for hepatitis B virus disease for both polymorphisms.

Odontoblast-like MDPC-23 cells produce pro-inflammatory IL-6 in response to lipoteichoic acid and express the antimicrobial peptide CRAMP

Objective: Odontoblasts are thought to be involved in innate immunity but their precise role in this process is not fully understood. Here, we assess effects of lipopolysaccharide (LPS) and lipoteichoic acid (LTA), produced by Gram-negative and Gram-positive bacteria, respectively, on matrix metalloproteinase-8 (MMP-8), interleukin-6 (IL-6) and cathelin-related antimicrobial peptide (CRAMP) expression in odontoblast-like MDPC-23 cells.Material and methods: Gene activity and protein production was determined by quantitative real-time RT-PCR and ELISA, respectively. Cellular expression of CRAMP was determined by immunocytochemistry.Results: Stimulation with LTA (5 and 25 µg/ml) but not LPS (1 and 5 µg/ml) for 24 h enhanced IL-6 mRNA expression. The LTA-induced up-regulation of IL-6 mRNA levels was associated with increased IL-6 protein levels. Stimulation with either LPS or LTA for 24 h lacked effect on both MMP-8 transcript and protein expression. Immunocytochemistry disclosed that MDPC-23 cells expressed immunoreactivity for CRAMP. MDPC-23 cells showed mRNA expression for CRAMP, but stimulation with either LPS or LTA did not modulate CRAMP transcript expression.Conclusions: We show that MDPC-23 cells possess immune-like cell properties such as LTA-induced IL-6 production and expression of the antimicrobial peptide CRAMP, suggesting that odontoblasts may modulate innate immunity via these mechanisms.

Associations of cytokine levels in gingival crevicular fluid of mobile teeth with clinical improvement after initial periodontal treatment

Studies suggest that analysis of gingival crevicular fluid (GCF) is useful for evaluating periodontal status. In this study, clinical variables related to tooth mobility, and multiple cytokine levels in proximate GCF, were measured at four time points during initial periodontal treatment: before treatment (baseline), after supragingival scaling, after occlusal adjustment, and after scaling and root planing (SRP); 20 teeth from 13 patients with periodontitis were included. Baseline interleukin (IL)-10 level in GCF was significantly higher around teeth that showed substantial improvement in periodontal epithelial surface area (PESA) after SRP than around teeth without PESA improvement. IL-3 and IL-16 levels in GCF at baseline were significantly higher around teeth with a periodontal inflamed surface area (PISA) of 0 mm² after SRP than around teeth without PISA improvement. In addition, baseline IL-7, IL-11, and IL-12p40 levels in GCF were significantly lower around teeth with decreased mobility after occlusal adjustment than around teeth without decreased mobility. These results suggest that pre-treatment cytokine levels in GCF are useful in predicting the effects of initial periodontal treatment.

Molecular inflammation and oxidative stress are shared mechanisms involved in both myocardial infarction and periodontitis

BACKGROUND AND OBJECTIVE

Our aims were to improve the understanding of the pathogenic relationship between cardiovascular diseases and periodontitis and to generate new perspectives in the prevention and treatment of acute myocardial infarction (AMI) and periodontitis. The present study evaluates possible differences in inflammation, oxidative stress, and autophagy markers among subject suffering AMI, periodontitis, or both, to explore possible common pathogenic mechanisms.

MATERIAL AND METHODS

A total of 260 subjects were enrolled in the study: 106 subjects that survived to a first AMI (AMI group) and 154 subjects had no cardiac events in their clinical record (control group). A questionnaire was used to assess age, height, weight, blood pressure, and heart rate. The clinical probing depth, clinical attachment loss, number of remaining teeth, and average number of sites with bleeding on probing were assessed. Lipid peroxidation and protein levels of phosphorylated AMP-activated protein kinase (p-AMPK) and microtubule-associated proteins 1A/1B-light chain 3-II (LC3-II) were determined in isolated peripheral blood mononuclear cells by thiobarbituric acid reactive substances (TBARS) assay and Western blot, respectively. Plasma levels of interleukin-1β were determined using a commercial ELISA kit. All the obtained variables were compared between subjects suffering an AMI with or without periodontitis and control subject periodontal healthy or with periodontitis.

RESULTS

A higher proportion of subjects suffering AMI + periodontitis than only AMI (without periodontitis) was found. Higher levels of TBARS were found in subjects with periodontitis than in subjects without periodontitis in both AMI and control subjects. Positive correlations between IL-1β levels and TBARS and between IL-1β levels and LC3-II were found only in control subjects.

CONCLUSION

Results from the present study are consistent with the suggestion of periodontitis as a potential risk factor for AMI. Periodontitis association with circulating lipid peroxides in both AMI and control subjects were found. The absence of differences in IL-1β levels between AMI subjects (only AMI vs AMI + periodontitis) suggests that oxidative stress could be the main pathogenic link between AMI and periodontitis.

Inflammatory Biomarkers, Microbiome, Depression, and Executive Dysfunction in Alcohol Users

Alcohol-related disorders (ARD) are highly prevalent among Latin American-Caribbean countries. Mental disorders are common comorbidities in individuals with ARD. However, the etiology of the association between ARD and mental disorders remains unclear. We examined the association of inflammatory cytokines, microbiome, and other biomakers with measures of depression, social anxiety, and executive functions. We observed a significant increase in cytokine and chemokine expression levels in saliva and plasma in the alcohol group (AG) samples. Also, the salivary bacterial composition in the AG revealed an abundance of Prevotella. Depression symptomatology was markedly higher in the AG, but social anxiety levels were negligible. AG also exhibited executive dysfunctions, which negatively correlated with increased plasma levels of pro-inflammatory cytokines and increased salivary concentrations of Prevotella bacteria. Our study suggests that chronic alcohol use correlates with executive dysfunction, immune system dysregulation, and dysbiosis of the salivary microbiota. Additional studies are needed to understand the role of the microbiome and inflammation in alcohol use and mental comorbidities.

Carotenoids and Periodontal Infection

Periodontitis is a polymicrobial infectious disease that leads to inflammation of the gingiva, resulting in teeth loss by various causes such as inflammation-mediated bone resorption. Recently, many investigators have reported that the periodontitis resulting from persistent low-grade infection of Gram-negative bacteria such as Porphyromonas gingivalis (Pg) is associated with increased atherosclerosis, diabetes mellitus, and other systemic diseases through blood stream. On the other hand, carotenoids belong among phytochemicals that are responsible for different colors of the foods. It is important to examine whether carotenoids are effective to the inhibition of periodontal infection/inflammation cascades. This review summarizes the advanced state of knowledge about suppression of periodontal infection by several carotenoids. A series of findings suggest that carotenoids intake may provide novel strategy for periodontitis treatment, although further study will be needed.

Between Innovation and Standardization, Is There Still a Room for Scientific Reports? The Rise of a Formatting Tradition in Periodontal Research

Everybody, regardless of their role, is aware that biomedical research is rapidly evolving, and the demand for reproducibility is increasing together with the amount of novel information. “Before reproducibility must come pre-producibility” “Checklists work to improve science”, just to quote some of the articles querying how to find a new bridge between ethics in science and the urgency for publishing. Looking for papers on anti-inflammatory compounds in periodontics, we came across a significant number of articles that could be considered a prototype of a consistent study format. The literature on the testing of active compounds on lipopolysaccharides- (LPS)-induced inflammation in gingival fibroblasts was searched to identify studies that followed a consistent format, to better understand their similarities and assess the appropriateness of their methods. Several studies were identified with a degree of similarity in their methods and formatting that was so high that it was possible to rule out that it was due to chance, and a format template common to these studies was outlined. Although this was most likely beyond the intentions of their authors, these studies may pose the basis for an in-vitro testing standard for anti-inflammatory compounds; however, the dangers of acritical uniformity are also apparent.

Role of gingival mesenchymal stem cell exosomes in macrophage polarization under inflammatory conditions

OBJECTIVE

Exosomes have been shown to play a strong role in intercellular communication. While GMSCs have been extensively studied, less research exists on exosomes derived from GMSCs, especially on how exosomes affect macrophages. This study aimed to investigate the impact of GMSC-derived exosomes on macrophage polarization and phenotype under inflammatory conditions.

METHODS

Exosomes were isolated from GMSCs-conditioned media by ultracentrifugation (UC) and characterized by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA) and western blot (WB). In vitro, GMSC-derived exosomes were co-incubated with macrophages for 24 h in the absence or presence of M1 polarizing conditions in the six-well plate. The protein and mRNA expression levels of M1 and M2 macrophage markers were detected and the supernatants were collected for an enzyme-linked immunosorbent assay (ELISA).

RESULTS

Exosomes were successfully isolated from GMSCs. Macrophages co-cultured with exosomes showed significantly decreased levels of the M1 markers Tumor Necrosis Factor-α (TNF-α), Interleukin-12 (IL-12), CD86 and Interleukin-1β (IL-1β). By contrast, M2 marker Interleukin-10 (IL-10) levels moderately increased. Meanwhile, similar results were acquired in the cell culture supernatants.

CONCLUSION

GMSC-derived exosomes may promote M1 macrophage transformation into M2 macrophages, reducing the pro-inflammatory factors produced by M1 macrophages.

Lymphatic growth factors are expressed in human gingiva and upregulated in gingival fibroblasts after stimulation

BACKGROUND

The lymphatic growth factors vascular endothelial growth factor (VEGF)-C and -D are important for maintenance and growth of lymphatic vessels (lymphangiogenesis), but their localization in human gingiva is unknown. This study investigated the expression of VEGF-C and -D in human gingiva and isolated human gingival fibroblasts (HGFs). In addition, the localization of their main receptor VEGFR-3 was explored.

METHODS

Non-inflamed gingiva from six donors was used for immunohistochemistry or isolation of HGFs. HGFs were stimulated with either E.coli lipopolysaccharide (LPS) or IL-6/soluble IL-6 receptor (sIL-6R) complex for 1, 6, and 24 hours. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to quantify the relative changes in gene expression of VEGF-A, -C, and -D and enzyme-linked immunosorbent assay (ELISA) for quantification of protein levels.

RESULTS

VEGF-C, -D and VEGFR-3 were seen in keratinocytes, blood vessels and in scattered single cells in gingiva. VEGFR-3 was also found in lymphatic vessels and VEGF-C in cells with fibroblastic appearance. Gene analysis showed no expression of VEGF-D in the HGFs, but showed constitutive expression of VEGF-C and -A. Stimulation of HGFs with LPS or IL-6/sIL-6R complex was followed by gene upregulation of VEGF-C and -A and increased protein levels in cell culture supernatant (P ≤0.05).

CONCLUSIONS

The localization of VEGF-C, -D, and VEGFR-3 expression imply that signaling via VEGFR-3 is linked to vascular homeostasis and keratinocyte function under normal conditions in gingiva. Inflammatory stimulation of HGFs upregulates VEGF-C and -A expression and may contribute to angiogenesis and lymphangiogenesis.

Interleukin-10 and Interleukin-1β Cytokines Expression in Leukocytes of Patients with Chronic Peri-Mucositis

BACKGROUND The purpose of the present research is to analyze the effect of polyphenols and flavonoids substrat (PFS) from plants Calendula officinalis, Salvia fruticosa, Achillea millefolium, and propolis as immunomodulatory in the production of interleukin (IL)-1ß and IL-10 in peripheral blood leukocytes medium (PBLM) in patients who were diagnosed with mucositis of peri-implant tissue compared to patients with healthy implant tissue. It was hypothesized that IL-1ß and IL-10 contribute to the inflammation processes noticed in the diseases of peri-implant tissues. MATERIAL AND METHODS Sixty non-smoking patients were included in this study: patients with healthy implants (HP group) and patients with peri-implant mucositis (MP group). Peri-mucositis was diagnosed by radiologic and clinical examination. The PBLM from MP were treated with PFS at various concentrations. The levels of IL-10 and IL-1ß excreted by the PBLM stimulated and unstimulated with viable Porphyromonas gingivalis test-tube were committed by the enzyme amplified immunoassay sensitivity method. RESULTS Unstimulated and stimulated PBLM and treatment with 5.0 mg/mL or 10.0 mg/mL of PFS in the MP group produced significantly higher levels IL-10 (P<0.001) that analogous mediums of the HP group. The levels of IL-1ß decreased more considerably in the stimulated PBLM of the MP group than in those of HP group (P<0.001) after the treatment with PFS at only 10.0 mg/mL concentration. CONCLUSIONS Theses results suggest that the solution of PFS might offer a new potential for the development of a new therapeutic path to prevent and treat peri-implant mucositis.

Effect of porous tantalum on the biological response of human peripheral mononuclear cells exposed to Porphyromonas gingivalis

AIM

To evaluate biological behavior of human peripheral mononuclear cells (PBMC) in contact with porous tantalum (PT) and Porphyromonas gingivalis (Pg).

METHODS

Pg was incubated for 8 hours. The groups formed were: PBMC (control), PBMC + PT, PBMC + Pg and PBMC + PT + Pg. Cell viability was evaluated using MTT assay. The morphology and adhesion of PBMC to PT was evaluated using scanning electron microscopy. Expression of interleukin (IL)-10, transforming growth factor (TGF)-β, matrix metallopeptidase (MMP)-9 and receptor activator of nuclear factor-κΒ ligand (RANKL) was determined by enzyme-linked immunosorbent assay.

RESULTS

MTT assay revealed that PT did not interfere in the mitochondrial activity of PBMC (P > .05). Scanning electron microscopy showed the adherence of PBMC to PT. IL-10 levels in PBMC + PT were similar to PBMC and lower than PBMC + Pg. TGF-β levels in PBMC + PT were higher than PBMC and PBMC + Pg. MMP-9 levels in PBMC + PT were similar to PBMC and lower than PBMC + Pg and PBMC + PT + Pg. RANKL levels in PBMC + PT were lower than in PBMC.

CONCLUSION

PT did not affect PBMC viability, allowed cell adhesion, reduced expression of RANKL and enhanced TGF-β in comparison with the control group.

Catechin ameliorates Porphyromonas gingivalis-induced inflammation via the regulation of TLR2/4 and inflammasome signaling

BACKGROUND

Porphyromonas gingivalis is a major periodontopathogen found in patients with chronic periodontitis that can lead to alveolar bone or tooth loss. Interleukin-1β (IL-1β), a proinflammatory cytokine, is most relevant to the pathogenesis of periodontitis. Catechin is one of the main polyphenol compounds found in green tea and possesses a range of health benefits. This study examined the anti-inflammatory effects of catechin in THP-1-derived macrophages infected with P. gingivalis as well as its effects on P. gingivalis-induced periodontitis in a mouse model.

METHODS

The cytokine levels and relevant protein expression in THP-1 cells were measured using an enzyme-linked immunosorbent assay and Western blot analysis, respectively. An apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) pyroptosome formation was measured by confocal laser scanning microscopy. Micro-computed tomography was used to determine the level of bone loss induced by a P. gingivalis oral infection.

RESULTS

Catechin attenuated the production of IL-1β by inhibiting pro-IL-1β expression via the downregulation of nuclear factor-κB, p38 mitogen-activated protein kinase, and Toll-like receptor signaling. In addition, catechin inhibited the activation of inflammasomes induced by P. gingivalis, but did not affect the growth of P. gingivalis. Catechin reduced the level of alveolar bone loss in a P. gingivalis-induced periodontitis mouse model.

CONCLUSION

Catechin possesses anti-inflammatory properties by reducing the level of IL-1β production, suggesting that it can potentially be used for the prevention and treatment of periodontal inflammation caused by P. gingivalis.

Pathological Characteristics of Periodontal Disease in Patients with Chronic Kidney Disease and Kidney Transplantation

Chronic kidney disease (CKD) is recognized as an irreversible reduction of functional nephrons and leads to an increased risk of various pathological conditions, including cardiovascular disease and neurological disorders, such as coronary artery calcification, hypertension, and stroke. In addition, CKD patients have impaired immunity against bacteria and viruses. Conversely, kidney transplantation (KT) is performed for patients with end-stage renal disease as a renal replacement therapy. Although kidney function is almost normalized by KT, immunosuppressive therapy is essential to maintain kidney allograft function and to prevent rejection. However, these patients are more susceptible to infection due to the immunosuppressive therapy required to maintain kidney allograft function. Thus, both CKD and KT present disadvantages in terms of suppression of immune function. Periodontal disease is defined as a chronic infection and inflammation of oral and periodontal tissues. Periodontal disease is characterized by the destruction of connective tissues of the periodontium and alveolar bone, which may lead to not only local symptoms but also systemic diseases, such as cardiovascular diseases, diabetes, liver disease, chronic obstructive pulmonary disease, and several types of cancer. In addition, the prevalence and severity of periodontal disease are significantly associated with mortality. Many researchers pay special attention to the pathological roles and clinical impact of periodontal disease in patients with CKD or KT. In this review, we provide information regarding important modulators of periodontal disease to better understand the relationship between periodontal disease and CKD and/or KT. Furthermore; we evaluate the impact of periodontal disease on various pathological conditions in patients with CKD and KT. Moreover, pathogens of periodontal disease common to CKD and KT are also discussed. Finally, we examine the importance of periodontal care in these patients. Thus, this review provides a comprehensive overview of the pathological roles and clinical significance of periodontal disease in patients with CKD and KT.

In Vitro Performance of Bioinspired Phenolic Nanocoatings for Endosseous Implant Applications

In the quest for finding new strategies to enhance tissue integration and to reduce the risk of bacterial colonization around endosseous implants, we report the application of auto-oxidative phenolic coatings made of tannic acid and pyrogallol to titanium surfaces. The functionalized surfaces were screened for their biological performance using cultures of primary human osteoblasts and biofilm-forming bioluminescent staphylococci S. epidermidis Xen43 and S. aureus Xen29. No toxic effect of the coatings on osteoblasts was detected. While tannic acid coatings seemed to induce a delay in osteoblast maturation, they revealed anti-inflammatory potential. Similar effects were observed for pyrogallol coatings deposited for 24 h. Thin pyrogallol coatings deposited for 2 h seemed to promote osteoblast maturation and revealed increased calcium deposition. The effects on osteoblast were found to be related to the release of phenolic compounds from the surfaces. While the phenolic coatings could not inhibit staphylococcal biofilm formation on the titanium surfaces, released phenolic compounds had an inhibitory effect the growth of planktonic bacteria. In conclusion, the assessed coating systems represent a versatile functionalization method which exhibit promising effects for endosseous implant applications.

Aliskiren Attenuates the Inflammatory Response and Wound Healing Process in Diabetic Mice With Periodontal Disease

The aim of this study was to characterize the role of local RAS (renin–angiotensin system) in the inflammatory response of normal (N) and diabetic (D) mice with periodontal disease (PD). Diabetes Mellitus (DM) was induced by peritoneal injection of streptozotocin in Balb/c mice. PD was induced by ligature around the first molar in both N and D, irrespective of whether they were treated with aliskiren (50 mg/kg, Alisk). Mandibles were harvested for histomorphometric analyses, and gingival tissue (GT) was collected to evaluate gene expression and extracellular matrix components (ECM). Immunohistochemical (IHC) analyses were used to localize RAS in GT. The production of C-reactive protein (CRP), IL-1β, CXCL2, and CCL8 was evaluated by enzyme-linked immunosorbent assay (ELISA). Renin was found to exacerbate the inflammation and periodontal bone loss at 14 days after PD, and Alisk inhibited this process in GT of N and D. PD increased CRP, CXCL2, CCL8, and IL-1β production in both animals. Alisk could inhibit CRP, CXCL2, and CCL8 primarily in D animals. However, only CCL8 was decreased in N animals after Alisk pretreatment. PD enhanced expression and production of AGT, ACE, AT1R, and AT2R in both N and D. AT1R expression was higher in D with PD, and AT2R expression was higher in N with PD. ACE2 and receptor Mas (MasR) expression and production was elevated in the control group of both animals. PD inhibited ACE2 in N but not in D. MasR expression was unaffected in both N and D with PD. Alisk reduced expression and production of all RAS components in GT of both animals, except for ACE2 in N. RAS staining was observed in all layers of epithelium, basal cell layer, and lamina propria and was higher in N with PD. Col1a1, Col1a2, Col3a1, and fibronectin (Fn1) were increased in both animals with PD. Alisk inhibited Col1a1 and Fn in both animals, Col1a2 was decreased only in D, while levels of Col3a1 remained unchanged in all animal groups. In conclusion, these data demonstrated the presence and functional role of local RAS in GT, exacerbating the inflammatory response, periodontal bone loss, and wound healing processes in both N and D animal groups. In addition, Alisk was able to significantly reduce gingival inflammation, excessive wound healing processes, and periodontal bone loss.

Effects of Er,Cr:YSGG and Diode Lasers on Clinical Parameters and Gingival Crevicular Fluid IL-1β and IL-37 Levels in Generalized Aggressive Periodontitis

Aim

The objective of the current study is to analyze the correlation between cytokine levels and periodontal parameters in aggressive periodontitis patients before and after periodontal treatment that was performed by using two different laser therapies.

Materials and Methods

Twenty-six generalized aggressive periodontitis patients were treated with three different methods (SRP, SRP+diode laser, and SRP+Er,Cr:YSGG laser) applied to three different half-jaws in the same patients. Pre- and posttreatment clinical periodontal parameters and GCF IL-1β and IL-37 levels were measured.

Results

There was a statistically significant decrease (p < 0.05) between pretreatment and posttreatment clinical periodontal parameters and IL-1β and IL-37 levels. When the reduction rates of IL-37 and IL-1β levels after treatment were evaluated, the decrease in IL-37 and IL-1β levels after treatment was lowest in the SRP group and highest in the SRP+Er,Cr:YSGG group. In addition, the amount of decrease in IL-1β in SRP+diode and SRP+Er,Cr:YSGG groups was found to be higher than that in IL-37. Furthermore, there was a positive correlation between IL-37 and IL-1β in all groups (p < 0.01).

Conclusion

Er,Cr:YSGG laser is more effective than diode laser for the treatment of aggressive periodontitis. IL-37 and IL-1β are cytokines that function together and thus must be evaluated together.

Histopathological and biochemical evaluation of the effect of Paeoniflorin on the periodontium during and after periodontitis formation in rats

OBJECTIVES

Appraise the effect of systemic Paeoniflorin (Pae) application on the periodontium during and after induction of experimental periodontitis in the presence of ligature and after its removal.

DESIGN

Seventy male Wistar rats were separated into seven equal groups. The first group was reserved as healthy control group (Group 1: no periodontitis, no medication) and experimental periodontitis was induced with ligature in the remaining rats. In experimental periodontitis groups, Pae or saline was administered systemically in three differet periods; during the experimental periodontitis induction (period 1), after experimental periodontitis induction which ligature removed (period 2) or ligature kept in position (period 3). Only, one of the groups acted as the control periodontitis group and received no treatment. Experimental periodontitis groups were as follows; Group 2: medication in period 1, Group 3: periodontitis and no medication, Group 4: medication in period 2, Group 5: saline application in period 2, Group 6: medication in period 3, Group 7: saline application in period 3. Matrix metalloproteinases-9 (MMP-9) levels and interleukin-10 (IL-10) levels were detected biochemically and histomorphometric analyses were performed. These analyses included measurements of the area of alveolar bone, the level of alveolar bone, and attachment loss.

RESULTS

Area of alveolar bone and IL-10 levels were higher in the Pae-administered groups; level of alveolar bone, attachment loss, and MMP-9 levels were correspondingly lower (P < 0.05). The beneficial effects at histomorphometrical and biochemical levels of Pae were the strongest in the rats that were administered Pae after the removal of ligature.

CONCLUSIONS

Systemically administered Pae had a positive effect on the healing of periodontal tissues. Pae can be used as a new therapeutic agent for periodontal diseases, but microbiology-based studies and more extensive biochemistry-based experimental and clinical studies are needed to address this possibility.

Nonulosonic acids contribute to the pathogenicity of the oral bacterium Tannerella forsythia

Periodontitis is a polymicrobial, biofilm-caused, inflammatory disease affecting the tooth-supporting tissues. It is not only the leading cause of tooth loss worldwide, but can also impact systemic health. The development of effective treatment strategies is hampered by the complicated disease pathogenesis which is best described by a polymicrobial synergy and dysbiosis model. This model classifies the Gram-negative anaerobe Tannerella forsythia as a periodontal pathogen, making it a prime candidate for interference with the disease. Tannerella forsythia employs a protein O-glycosylation system that enables high-density display of nonulosonic acids via the bacterium's two-dimensional crystalline cell surface layer. Nonulosonic acids are sialic acid-like sugars which are well known for their pivotal biological roles. This review summarizes the current knowledge of T. forsythia's unique cell envelope with a focus on composition, biosynthesis and functional implications of the cell surface O-glycan. We have obtained evidence that glycobiology affects the bacterium's immunogenicity and capability to establish itself in the polymicrobial oral biofilm. Analysis of the genomes of different T. forsythia isolates revealed that complex protein O-glycosylation involving nonulosonic acids is a hallmark of pathogenic T. forsythia strains and, thus, constitutes a valuable target for the design of novel anti-infective strategies to combat periodontitis.

Calcium and vitamin D supplementation and/or periodontal therapy in the treatment of periodontitis among Brazilian pregnant women: protocol of a feasibility randomised controlled trial (the IMPROVE trial)

Background

Periodontitis is a common oral inflammation, which is a risk factor for adverse pregnancy outcomes. Intakes of vitamin D and calcium are inversely associated with occurrence and progression of periodontitis. This study aims to assess the feasibility of a multi-component intervention, including provision of milk powder supplemented with calcium and vitamin D and periodontal therapy (PT), for improving maternal periodontal health and metabolic and inflammatory profiles of low-income Brazilian pregnant women with periodontitis.

Methods

The IMPROVE trial is a feasibility randomised controlled trial (RCT) with a 2 × 2 factorial design with a parallel process evaluation. Pregnant women with periodontitis, aged 18–40 years and with < 20 gestational weeks (n = 120) were recruited and randomly allocated into four groups: (1) fortified sachet (vitamin D and calcium) and powdered milk plus PT during pregnancy, (2) placebo sachet and powdered milk plus PT during pregnancy, (3) fortified sachet (vitamin D and calcium) and powdered milk plus PT after delivery and (4) placebo sachet and powdered milk plus PT after delivery. Dentists and participants are blinded to fortification. Acceptability of study design, recruitment strategy, random allocation, data collection procedures, recruitment rate, adherence and attrition rate will be evaluated. Data on serum levels of vitamin D, calcium and inflammatory biomarkers; clinical periodontal measurements; anthropometric measurements; and socio-demographic questionnaires are collected at baseline, third trimester and 6–8 weeks postpartum. Qualitative data are collected using focus group, for analysis of favourable factors and barriers related to study adherence.

Discussion

Oral health and mineral/vitamin supplementation are much overlooked in the public prenatal assistance in Brazil and of scarcity of clinical trials addressing these issues in low and middle-income countries,. To fill this gap the present study was designed to assess the feasibility of a RCT on acceptability of a multi-component intervention combining conventional periodontal treatment and consumption of milk fortified with calcium-vitamin D for improving periodontal conditions and maternal metabolic and inflammation status, among Brazilian low-income pregnant women with periodontitis. Thus, we hope that this relatively low-cost and safe multicomponent intervention can help reduce inflammation, improve maternal periodontal health and metabolic profile and consequently prevent negative gestational outcomes.

Trial registration

NCT, NCT03148483. Registered on May 11, 2017.

Association between Periodontal Disease and Subsequent Sjögren's Syndrome: A Nationwide Population-Based Cohort Study

Xerostomia (dry mouth) is the cardinal symptom of Sjögren’s syndrome (SS), which is an autoimmune disease involving the exocrine glands and other organs. Xerostomia may predispose patients to periodontal disease (PD) and an association between SS and PD has been reported. This association may be bidirectional; therefore, we conducted this study to investigate the risk of SS in patients with PD using data from the National Health Insurance Research Database of Taiwan. A total of 135,190 patients were enrolled in our analysis. In all, 27,041 patients with PD were matched by gender, age, insured region, urbanization and income, with cases and controls in a 1:4 ratio. Both groups were followed and the risks of SS were calculated by Cox proportional hazards regression. Finally, 3292 (2.4%) patients had newly diagnosed SS. Patients with PD had a significantly higher risk of subsequent SS (903 (3.3%) vs. 2389 (2.2%), adjusted hazard 1.47, 95% confidence interval: 1.36–1.59). In conclusion, patients with PD had an approximately 50% increased risk of subsequent SS. Physicians should be aware of the symptoms and signs of SS in patients with PD.

Wine-Derived Phenolic Metabolites in the Digestive and Brain Function

Wine, and specifically red wine, is a beverage with a great chemical complexity comprising a particular combination of phenolic compounds which are directly associated with its health-promoting properties. Wine polyphenols could induce changes in the composition of intestinal microbiota that would affect the production of physiologically active phenolic metabolites modifying the content and phenolic profile at the systemic level. In addition, in the human population, it seems that different “metabotypes”, or patterns of metabolizing wine polyphenols, exist, which would be reflected in the different biological fluids (i.e., plasma, urine and feces) and tissues of the human body. Moreover, wine polyphenols might change the composition of oral microbiota by an antimicrobial action and/or by inhibition of the adhesion of pathogens to oral cells, thus contributing to the maintenance of oral health. In turn, polyphenols and/or its metabolites could have a direct action on brain function, by positively affecting signaling routes involved in stress-induced neuronal response, as well as by preventing neuroticism-like disorders (i.e., anxiety and depression) through anti-inflammatory and epigenetic mechanisms. All of this would condition the positive effects on health derived from moderate wine consumption. This paper reviews all these topics, which are directly related with the effects of wine polyphenols at both digestive and brain level. Further progresses expected in the coming years in these fields are also discussed.

Identification of Genes Differentially Expressed in Simvastatin-Induced Alveolar Bone Formation

Local delivery of simvastatin (SIM) has exhibited potential in preventing inflammation and limiting bone loss associated with experimental periodontitis. The primary aim of this study was to analyze transcriptome changes that may contribute to SIM's reduction of periodontal inflammation and bone loss. We evaluate the global genetic profile and signaling mechanisms induced by SIM on experimental periodontitis bone loss and inflammation. Twenty mature female Sprague Dawley rats were subjected to ligature-induced experimental periodontitis around maxillary second molars (M2) either unilaterally (one side untreated, n = 10) or bilaterally (n = 10). After the ligature removal at day 7, sites were injected with either carrier, pyrophosphate (PPi ×3), 1.5-mg SIM-dose equivalent SIM-pyrophosphate prodrug, or no injection. Three days after ligature removal, animals were euthanized; the M1-M2 interproximal was evaluated with μCT, histology, and protein expression. M2 palatal gingiva was harvested for RNA sequencing. Although ligature alone caused upregulation of proinflammatory and bone catabolic genes and proteins, seen in human periodontitis, SIM-PPi upregulated anti-inflammatory (IL-10, IL-1 receptor-like 1) and bone anabolic (insulin-like growth factor, osteocrin, fibroblast growth factor, and Wnt/ β-catenin) genes. The PPi carrier alone did not have these effects. Genetic profile and signaling mechanism data may help identify enhanced pharmacotherapeutic approaches to limit or regenerate periodontitis bone loss. © 2018 The Authors. JBMR Plus Published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.

Sphingosine-1-Phosphate Receptor 2 Controls Podosome Components Induced by RANKL Affecting Osteoclastogenesis and Bone Resorption

Proinflammatory cytokine production, cell chemotaxis, and osteoclastogenesis can lead to inflammatory bone loss. Previously, we showed that sphingosine-1-phosphate receptor 2 (S1PR2), a G protein coupled receptor, regulates inflammatory cytokine production and osteoclastogenesis. However, the signaling pathways regulated by S1PR2 in modulating inflammatory bone loss have not been elucidated. Herein, we demonstrated that inhibition of S1PR2 by a specific S1PR2 antagonist (JTE013) suppressed phosphoinositide 3-kinase (PI3K), mitogen-activated protein kinases (MAPKs), and nuclear factor kappa-B (NF-κB) induced by an oral bacterial pathogen, Aggregatibacter actinomycetemcomitans, and inhibited the release of IL-1β, IL-6, TNF-α, and S1P in murine bone marrow cells. In addition, shRNA knockdown of S1PR2 or treatment by JTE013 suppressed cell chemotaxis induced by bacteria-stimulated cell culture media. Furthermore, JTE013 suppressed osteoclastogenesis and bone resorption induced by RANKL in murine bone marrow cultures. ShRNA knockdown of S1PR2 or inhibition of S1PR2 by JTE013 suppressed podosome components, including PI3K, Src, Pyk2, integrin β_3, filamentous actin (F-actin), and paxillin levels induced by RANKL in murine bone marrow cells. We conclude that S1PR2 plays an essential role in modulating proinflammatory cytokine production, cell chemotaxis, osteoclastogenesis, and bone resorption. Inhibition of S1PR2 signaling could be a novel therapeutic strategy for bone loss associated with skeletal diseases.

The Effects of Non-Thermal Atmospheric Pressure Plasma treated Titanium Surface on Behaviors of Oral Soft Tissue Cells

Here, we investigated the possible use of the technology known as non-thermal atmospheric pressure plasma on integration and control of cytokine release of soft tissue on titanium surface. After NTAPP was applied to titanium samples, changes of surface characteristics were measured as topographical features, contact angle, surface tension, and with X-ray photoelectron spectroscopy (XPS). Protein absorption was evaluated using a bovine serum albumin absorption assay. The attachment, viability, morphology, proliferation, and cytokine release of soft tissue on titanium were assessed. No change in topographical features was observed between control and NTAPP-treated groups. However, NTAPP treatment resulted in significant lowering of the contact angle for polar and non-polar liquids and increase of surface tension. Protein absorption was significantly enhanced on the NTAPP-treated samples. Normal soft tissue attachment was improved on the NTAPP-treated groups with good viability. Cellular morphology was improved in NTAPP-treated groups whereas cellular proliferation was not enhanced. There was a significant reduction in the amounts of cytokine release for inflamed IHOK and hTERT-hNOF on the NTAPP-treated groups; except for IL-8 for IHOKs. This study demonstrates that surface functional consequences by NTAPP exposure enhanced behavior of oral soft tissue cells without topographical change.

In vivo evaluation of chitosan based local delivery systems for atorvastatin in treatment of periodontitis

Periodontitis is a local inflammatory disease initiated by bacteria accumulation and results in cytokine mediated alveolar bone resorption and tissue destruction. In this study, the effect of locally delivered atorvastatin (2% w/v) containing chitosan formulations in the treatment of periodontitis was evaluated in rats with ligature induced periodontitis. The levels of interleukin-1beta (IL-1β), IL-6, IL-8, IL-10, transforming growth factor-β1 (TGF-β1), TGF-β2 and TGF-β3 were measured after treatment with formulations. Histomorphometric analysis included the measurements of the area of alveolar bone and the distance between cemento-enamel junction (CEJ) and connective tissue attachment to tooth. Inflammatory and osteoclastic activity scores were given semiquantitatively. Following the administration of atorvastatin, release of pro-inflammatory (IL-1β, IL-6 and IL-8) and anti-inflammatory (TGF-β1 and TGF-β2) cytokines was found to decrease, with a significant alveolar bone healing, when compared to that of control. The anti-inflammatory effect was observed to enhance in presence of chitosan. These findings suggest that chitosan based delivery system for a statin group drug, atorvastatin is a promising for the treatment of periodontal disease.

Development and in vitro evaluation of chitosan based system for local delivery of atorvastatin for treatment of periodontitis

In recent years, statin group drugs have been widely investigated in treatment of periodontal diseases due to their anti-inflammatory effect. The efficacy of statins can be enhanced by local administration into the periodontal pocket by appropriate delivery systems. The aim of our study was to develop a bioadhesive delivery system for local delivery of atorvastatin in treatment of periodontal disease. For this purpose, gel formulations were prepared using different types of chitosan (base and water soluble) and viscosity, bioadhesivity and syringeability of the gels as well as in vitro drug release properties were investigated vitro. Furthermore, anti-inflammatory effect of the formulations was studied in vitro using tumor necrosis factor (TNF)-alfa induced human gingival fibroblast (hGF) cells. Release of proinflammatory (IL-1β, IL-6, IL-8) and anti-inflammatory (TGF-β1, TGF-β2, TGF-β3, IL-10) cytokines were measured after incubating the hGF cells with the formulations. The viscosity of the formulations was found to be suitable for a local application into periodontal pocket. In presence of drug, bioadhesive property of the formulations was found to increase, and bioadhesion force was within the range, which would retain the delivery system at the application site, subsequently maintain drug levels at desired amount for longer period of time. The release of atorvastatin from the gels was found to be slower than that of the solution. The cytokine levels were found to decrease following application of the formulations, and anti-inflammatory effect was observed to enhance in presence of chitosan. No significant differences were found between base and water-soluble chitosan.

Is overweight/obesity a risk factor for periodontitis in young adults and adolescents?: a systematic review

BACKGROUND

Obesity in young adults and adolescents is associated with chronic co-morbidities. This project investigated whether being overweight or obese is a risk factor for periodontitis in adolescents (13-17 years) and young adults (18-34 years).

METHODS

A search of 12 databases was conducted using Medical Subject Headings/Index and Emtree terms. Based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, articles published between 2003 and 2016 were screened that reported periodontal and anthropometric measures. The Newcastle-Ottawa Scale was used to appraise the quality of studies.

RESULTS

Of 25 eligible studies from 12 countries, 17 showed an association between obesity and periodontitis (odds ratios ranged from 1.1 to 4.5). The obesity indicators of body mass index, waist circumference, waist-hip ratio and body fat percentage were significantly associated with measures of periodontitis of bleeding on probing, plaque index, probing depths, clinical attachment loss, calculus, oral hygiene index and community periodontal index. Two prospective cohort studies in the review showed no significant association between obesity and periodontitis, but these studies had limitations of study design and used inappropriate epidemiological diagnostic measures of periodontitis.

CONCLUSION

There was evidence to suggest that obesity is associated with periodontitis in adolescents and young adults. Systematic Review Registration: PROSPERO Registration Number: CRD42016046507.

Sialidase Deficiency in Porphyromonas gingivalis Increases IL-12 Secretion in Stimulated Macrophages Through Regulation of CR3, IncRNA GAS5 and miR-21

Porphyromonas gingivalis (P. gingivalis) is a major periodontal pathogen that can induce an immune response leading to a destructive inflammatory process. During the inflammatory process, interleukin-12 (IL-12) is secreted, correlating with bacterial clearance by macrophages. Bacterial sialidase has recently been shown to influence the synthesis and modification of the macromolecules on its surface, and is associated with the interaction between bacteria and host cells. We have previously constructed a P. gingivalis sialidase gene mutant strain in P. gingivalis W83 (ΔPG0352) and found that ΔPG0352 showed less pathogenicity than the wild-type strain. In this study, U937-differentiated macrophages were stimulated by P. gingivalis W83, ΔPG0352, or PG0352 complemented strain (comΔPG0352). Transmission electron microscopy showed that P. gingivalis caused a loss of membrane integrity in macrophages and the intracellular bacteria were enclosed within endocytic vacuoles. The expression of both IL-12p35 and IL-12p40 genes and the levels of IL-12p70 were significantly higher in U937 stimulated by ΔPG0352 than in those with P. gingivalis W83 and comΔPG0352. In order to explain why ΔPG0352 induced more IL-12 in macrophages, immunofluorescence assays, PCR arrays, and gene silence or overexpression experiments were carried out. Immunofluorescence assays showed that ΔPG0352 induced lower expression of CR3 in macrophages. After CR3 was suppressed, there were no significant differences in the IL-12p70 levels between macrophages stimulated by P. gingivalis W83, ΔPG0352 or comΔPG0352. PCR array experiments showed that miR-21 and lncRNA GAS5 were differentially expressed between macrophages stimulated by P. gingivalis W83 and ΔPG0352, which had been identified by real-time PCR. The results of CR3 blocking and lncRNA GAS5 gene silence or overexpression showed that the difference in IL-12 levels between P. gingivalis W83 and ΔPG0352 groups was associated with CR3, lncRNA GAS5 and miR-21. Thus it can be concluded that the sialidase-deficient strain is more easily cleared by attenuating CR3 activation, reducing the inhibition of lncRNA GAS5, inducing less miR-21 and more IL-12 in macrophages. These results indicate that inhibiting the activity of sialidase in P. gingivalis will cause rapid clearing by macrophages.