Tissue Destruction In Periodontitis Research Articles

Inflammation indices in association with periodontitis and cancer.

Inflammation is a complex physiological process that plays a pivotal role in many if not all pathological conditions, including infectious as well as inflammatory diseases, like periodontitis and autoimmune disorders. Inflammatory response to periodontal biofilms and tissue destruction in periodontitis is associated with the release of inflammatory mediators. Chronic inflammation can promote the development of cancer. Persistence of inflammatory mediators plays a crucial role in this process. Quantification and monitoring of the severity of inflammation in relation to cancer is essential. Periodontitis is mainly quantified based on the severity and extent of attachment loss and/or pocket probing depth, in addition with bleeding on probing. In recent years, studies started to investigate inflammation indices in association with periodontal diseases. To date, only few reviews have been published focusing on the relationship between blood cell count, inflammation indices, and periodontitis. This review presents a comprehensive overview of different systemic inflammation indices, their methods of measurement, and the clinical applications in relation to periodontitis and cancer. This review outlines the physiological basis of inflammation and the underlying cellular and molecular mechanisms of the parameters described. Key inflammation indices are commonly utilized in periodontology such as the neutrophil to lymphocyte ratio. Inflammation indices like the platelet to lymphocyte ratio, platelet distribution width, plateletcrit, red blood cell distribution width, lymphocyte to monocyte ratio, delta neutrophil index, and the systemic immune inflammation index are also used in hospital settings and will be discussed. The clinical roles and limitations, relationship to systemic diseases as well as their association to periodontitis and treatment response are described.

Neural epidermal growth factor-like 1 protein (Nell-1) alleviates periodontal tissue destruction in periodontitis by regulating the ratio of M2/M1 macrophage phenotypes

BackgroundPeriodontitis is a common oral disease with high prevalence worldwide. Neural epidermal growth factor-like 1 protein (Nell-1) has recently been reported to have anti-inflammation effects and may be a drug candidate for osteoarthritis. However, its immunotherapeutic effects in periodontitis remain unknown. Therefore, this study aimed to investigate the effects of Nell-1 on periodontitis in terms of macrophage polarization and analyze its possible underlying mechanism. MethodsA rat ligation-induced experimental periodontitis model was established and locally injected with Nell-1 (n = 6/group). Periodontal tissue destruction and macrophage polarization in vivo were analyzed using micro-CT, histology analysis, and western blot. Enzyme-linked immunosorbent assay was used to evaluate serum inflammatory cytokines. Then, the RAW 264.7 macrophage cells were treated with lipopolysaccharide (LPS), Nell-1, and the c-Jun N-terminal kinases (JNK) inhibitor (SP600125). RT-PCR, western blot, and flow cytometry were performed to further analyze the effect of Nell-1 on macrophage polarization and the underlying mechanism in vitro. ResultsLocal treatment with Nell-1 significantly alleviated the destruction of alveolar bone and fibers in periodontitis, and upregulated the ratio of M2/M1 macrophages in periodontal tissues (P < 0.05). In vitro, Nell-1 at the concentrations of 200 and 500 ng/mL could significantly inhibit the expression of M1-related inflammatory factors in LPS-stimulated macrophages, and increase the expression of M2-related markers, regulating the macrophage phenotype switch into M2 (P < 0.05). The mRNA of JNK and relative protein level of phospho-JNK/JNK were also upregulated by Nell-1 (P < 0.05). Additionally, the JNK inhibitor (SP600125) could reverse the effect of Nell-1 on macrophage polarization (P < 0.05). ConclusionsNell-1 could modulate the ratio of M2/M1 macrophages possibly through the JNK/MAPK signaling pathway, subsequently attenuating the inflammation and destruction of periodontal tissues caused by periodontitis.

AZGP1 Aggravates Macrophage M1 Polarization and Pyroptosis in Periodontitis

Periodontal tissue destruction in periodontitis is a consequence of the host inflammatory response to periodontal pathogens, which could be aggravated in the presence of type 2 diabetes mellitus (T2DM). Accumulating evidence highlights the intricate involvement of macrophage-mediated inflammation in the pathogenesis of periodontitis under both normal and T2DM conditions. However, the underlying mechanism remains elusive. Alpha-2-glycoprotein 1 (AZGP1), a glycoprotein featuring an MHC-I domain, has been implicated in both inflammation and metabolic disorders. In this study, we found that AZGP1 was primarily colocalized with macrophages in periodontitis tissues. AZGP1 was increased in periodontitis compared with controls, which was further elevated when accompanied by T2DM. Adeno-associated virus-mediated overexpression of Azgp1 in the periodontium significantly enhanced periodontal inflammation and alveolar bone loss, accompanied by elevated M1 macrophages and pyroptosis in murine models of periodontitis and T2DM-associated periodontitis, while Azgp1-/- mice exhibited opposite effects. In primary bone marrow–derived macrophages stimulated by lipopolysaccharide (LPS) or LPS and palmitic acid (PA), overexpression or knockout of Azgp1 markedly upregulated or suppressed, respectively, the expression of macrophage M1 markers and key components of the NLR Family Pyrin Domain Containing 3 (NLRP3)/caspase-1 signaling. Moreover, conditioned medium from Azgp1-overexpressed macrophages under LPS or LPS+PA stimulation induced higher inflammatory activation and lower osteogenic differentiation in human periodontal ligament stem cells (hPDLSCs). Furthermore, elevated M1 polarization and pyroptosis in macrophages and associated detrimental effects on hPDLSCs induced by Azgp1 overexpression could be rescued by NLRP3 or caspase-1 inhibition. Collectively, our study elucidated that AZGP1 could aggravate periodontitis by promoting macrophage M1 polarization and pyroptosis through the NLRP3/casapse-1 pathway, which was accentuated in T2DM-associated periodontitis. This finding deepens the understanding of AZGP1 in the pathogenesis of periodontitis and suggests AZGP1 as a crucial link mediating the adverse effects of diabetes on periodontal inflammation.

CCL5's Role in Periodontal Disease: A Narrative Review.

Persistent host inflammatory and immune responses to biofilm play a critical role in the mechanisms that govern soft and hard tissue destruction in periodontal disease. Among the less explored facets of these mechanisms are chemokines, including CCL5 (C-C motif chemokine ligand 5), also known as RANTES (regulated on activation, normal T cell expressed and secreted), a proinflammatory CC subfamily chemokine synthesized by T lymphocytes. Despite its importance, there is currently no comprehensive review of the role of CCL5 in periodontitis in the literature. Therefore, this paper aims to fill this gap by summarizing the existing knowledge on the involvement of CCL5 in the onset and progression of periodontitis. In addition, we aim to stimulate interest in this relatively overlooked factor among periodontitis researchers, potentially accelerating the development of drugs targeting CCL5 or its receptors. The review examines the association of CCL5 with periodontitis risk factors, including aging, cigarette smoking, diabetes, and obesity. It discusses the involvement of CCL5 in pathological processes during periodontitis, such as connective tissue and bone destruction. The data show that CCL5 expression is observed in affected gums and gingival crevicular fluid of periodontitis patients, with bacterial activity contributing significantly to this increase, but the reviewed studies of the association between CCL5 expression and periodontal disease have yielded inconclusive results. Although CCL5 has been implicated in the pathomechanism of periodontitis, a comprehensive understanding of its molecular mechanisms and significance remains elusive, hindering the development of drugs targeting this chemokine or its receptors.

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 invivo. 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.

Osteoimmunology in Periodontitis and Orthodontic Tooth Movement.

Toreview the role of the immune cells and their interaction with cells found in gingiva, periodontal ligament, and bone that leads to net bone loss in periodontitis or bone remodeling in orthodontic tooth movement. Periodontal disease is one of the most common oral diseases causing inflammation in the soft and hard tissues of the periodontium and is initiated by bacteria that induce a host response. Although the innate and adaptive immune response function cooperatively to prevent bacterial dissemination, they also play a major role in gingival inflammation and destruction of the connective tissue, periodontal ligament, and alveolar bone characteristic of periodontitis. The inflammatory response istriggered by bacteria or their products that bind to pattern recognition receptors that induce transcription factoractivityto stimulatecytokine and chemokineexpression. Epithelial, fibroblast/stromal, and resident leukocytes play a key role in initiating the host response and contribute to periodontal disease. Single-cell RNA-seq (scRNA-seq) experiments have added new insight into the roles of various cell types in the response to bacterial challenge. This response is modified by systemic conditions such as diabetes and smoking. In contrast to periodontitis, orthodontic tooth movement (OTM) is a sterile inflammatory response induced by mechanical force. Orthodontic force application stimulates acute inflammatory responses in the periodontal ligament and alveolar bone stimulated by cytokines and chemokines that produce bone resorption on the compression side. On the tension side, orthodontic forces induce the production of osteogenic factors, stimulating new bone formation. A number ofdifferent celltypes, cytokines, and signaling/pathways are involved in this complex process. Inflammatory and mechanical force-induced bone remodeling involves bone resorption and bone formation. The interaction of leukocytes with host stromal cells and osteoblastic cells plays a key role in both initiating the inflammatory events as well as inducing a cellular cascade that results in remodeling in orthodontic tooth movement or in tissue destruction in periodontitis.

Probing antibacterial drugs for Fusobacterium nucleatum subsp. nucleatum ATCC 25586 targeting UDP-N-acetylglucosamine 1-carboxyltransferase.

Fusobacterium nucleatum is a Gram-negative anaerobic bacteria that is commonly found in oral cavities and is associated with connective tissue destruction in periodontitis. UDP-N-acetylglucosamine 1-carboxyltransferase with enzyme commission number 2.5.1.7 is a transferases enzyme that plays a role in bacterial pathogenesis. Inhibiting binding sites of UDP-N-acetylglucosamine 1-carboxyltransferase is needed to find potential antibiotic candidates for periodontitis treatment. Hence, the research aimed to present potential UDP-N-acetylglucosamine 1-carboxyltransferase inhibiting compounds through molecular docking simulation by in silico analysis. DrugBank database was used to obtain the antibacterial candidates, which were further screened computationally using the AutoDock Vina program on Google Colab Pro. The top nine compounds yielded binding affinity ranging from -12.1 to -12.8 kcal/mol, with conivaptan as one of the three compounds having the highest binding affinity. Molecular dynamic study revealed that the ligand-protein complex for conivaptan had root-mean-square deviation values of 0.05-1.1 nm, indicating likeliness for stable interaction. Our findings suggest that conivaptan is the potent UDP-N-acetylglucosamine 1-carboxyltransferase inhibitor, hence its efficacy against periodontitis-causing bacteria.

Anti-Inflammatory Effects of (3S)-Vestitol on Peritoneal Macrophages.

The isoflavone (3S)-vestitol, obtained from red propolis, has exhibited anti-inflammatory, antimicrobial, and anti-caries activity; however, few manuscripts deal with its anti-inflammatory mechanisms in macrophages. The objective is to elucidate the anti-inflammatory mechanisms of (3S)-vestitol on those cells. Peritoneal macrophages of C57BL6 mice, stimulated with lipopolysaccharide, were treated with 0.37 to 0.59 µM of (3S)-vestitol for 48 h. Then, nitric oxide (NO) quantities, macrophages viability, the release of 20 cytokines and the transcription of several genes related to cytokine production and inflammatory response were evaluated. The Tukey–Kramer variance analysis test statistically analyzed the data. (3S)-vestitol 0.55 µM (V55) lowered NO release by 60% without altering cell viability and diminished IL-1β, IL-1α, G-CSF, IL-10 and GM-CSF levels. V55 reduced expression of Icam-1, Wnt5a and Mmp7 (associated to inflammation and tissue destruction in periodontitis) and Scd1, Scd2, Egf1 (correlated to atherosclerosis). V55 increased expression of Socs3 and Dab2 genes (inhibitors of cytokine signaling and NF-κB pathway), Apoe (associated to atherosclerosis control), Igf1 (encoder a protein with analogous effects to insulin) and Fgf10 (fibroblasts growth factor). (3S)-vestitol anti-inflammatory mechanisms involve cytokines and NF-κB pathway inhibition. Moreover, (3S)-vestitol may be a candidate for future in vivo investigations about the treatment/prevention of persistent inflammatory diseases such as atherosclerosis and periodontitis.

Can the delta neutrophil ındex be used as a preliminary biomarker ın the evaluation of periodontal disease: a pilot study.

Objective:Tissue destruction in periodontal diseases is related to inflammatory mediators in the host. However, it is unknown whether a relationship between delta neutrophil index (DNI) and neutrophil-lymphocyte ratio (NLR) in Stage 3 Grade A patients occurs. This cross-sectional study aimed to investigate the relationship between periodontal disease and DNI and NLR.Methodology:The study included 74 systemically healthy, non-smoking adults separated into 3 groups. Group 1: 26 subjects with good periodontal health, Group 2: 26 subjects with gingivitis, and Group 3: 22 subjects with Stage 3 Grade A periodontitis. After determining which group the patient will be included in, a clinical periodontal examination was made of each patient and pocket depth (PD), clinical attachment level (CAL), gingival index (GI), bleeding on probing (BOP) and plaque index (PI) parameters were measured. Venous blood samples were taken and examined with an automatic hematology analyzer for DNI, immature granulocytes (IG), NLR, C-reactive protein (CRP), procalcitonin, neutrophil count and lymphocyte count.Results:DNI, IG, CRP, and neutrophil count were observed to be highest in Group 3, followed by Group 2, and the difference between the groups in these parameters was determined to be statistically significant (p<0.001, p<0.001, p=0.046, p=0.016). DNI, IG, CRP and neutrophil count were observed to be positively correlated with periodontal parameters.Conclusion:The findings of this study support the role of DNI as a new biomarker for periodontal diseases. DNI may better reflect the systemic level of stage 3 grade A periodontitis than traditional inflammatory markers.

Role of High Mobility Group Box 1 and Receptor for Advanced Glycation End Products in the Periodontal Disease Pathogenesis- A Review

Periodontitis is a multifactorial chronic inflammatory disease associated with increased secretion of several proinflammatory mediators such as Interleukin-1β (IL-1β), Interleukin-6 (IL-6), Interleukin-17 (IL-17), Tumour Necrosis Factor-α (TNF-α), Prostaglandins (PGs) in response to increased bacterial load on the tooth surface and within the gingival sulcus leading to the destruction of both hard and soft tissue of the periodontium. The Receptor for Advanced Glycation End-products (RAGE) binds multiple ligands, has a transmembrane configuration and is a part of the immunoglobulin receptor family. In healthy individuals RAGE is expressed at lower levels when compared to those with periodontitis and diabetes mellitus. Binding of RAGE to its ligands plays a key role in the inflammatory reactions that lead to disruption of a multitude of cellular processes. One such RAGE ligand involved in inducing hyperinflammatory phenotype is High Mobility Group Box 1 (HMGB1). HMGB1 is a chromatin binding protein predominantly localised in the nucleus and is associated with multiple functions such as Deoxyribonucleic Acid (DNA) repair, nuclear homeostasis, genome stability. In the presence of stressors, it migrates extracellularly and behaves like a Damage Associated Molecular Pattern (DAMP), has chemokine and cytokine activity. Extracellular HMGB1 binds to Toll Like Receptors (TLR)- 2,4 and RAGE, the HMGB1-RAGE interaction in particular has been associated with hyper inflammatory responses and currently hypothesised to be a bigger player in the pathogenesis of periodontitis as well as diabetes associated periodontitis. Therefore, understanding thoroughly the molecular mechanisms driving the tissue destruction in periodontal disease will effectively enable novel therapeutic drug based interventions based on interrupting the HMGB1-RAGE axis which in turn could mitigate the inflammation mediated tissue destruction.

Baicalin suppresses lipopolysaccharide-induced matrix metalloproteinase expression: action via the mitogenactivated protein kinase and nuclear factor κB-related protein signaling pathway

Periodontal disease is an inflammatory disease that affects the destruction of the bone supporting the tooth and connective tissues surrounding it. Periodontal ligament fibroblasts (PDLFs) induce overexpression of matrix metalloproteinase (MMP) involved in periodontal diseaseʼs inflammatory destruction. Osteoclasts take part in physiological bone remodeling, but they are also involved in bone destruction in many kinds of bone diseases, including osteoporosis and periodontal disease. This study examined the effect of baicalin on proteolytic enzymesʼ production and secretion of inflammatory cytokines in PDLFs and RAW 264.7 cells under the lipopolysaccharide (LPS)-induced inflammatory conditions. Baicalin inhibited the expression of the protein, MMP-1 and MMP-2, without affecting PDLFs’ cell viability, suggesting its possibility because of the inhibition of phosphorylation activation of mitogen-activated protein kinase’s p38, and the signal transduction process of nuclear factor κB (NFκB)-related protein. Also, baicalin reduced the expression of MMP-8 and MMP-9 in RAW 264.7 cells. This reduction is thought to be due to the inhibition of the signal transduction process of NFκB-related proteins affected by inhibiting p65RelA phosphorylation. Also, baicalin inhibited the secretion of nitric oxide and interleukin-6 induced by LPS in RAW 264.7 cells. These results suggest that baicalin inhibits connective tissue destruction in periodontal disease. The inhibition of periodontal tissue destruction may be a therapeutic strategy for treating inflammatory periodontal-diseased patients.

Inflammasome dysregulation in human gingival fibroblasts in response to periodontal pathogens.

Uncontrolled production of Interleukin-1β (IL-1β), a major proinflammatory cytokine, is associated with tissue destruction in periodontal disease. IL-1β production is controlled by inflammasomes which are multiprotein regulatory complexes. The current study aimed to elucidate potential regulatory pathways by monitoring the effects of periodontal pathogens Fusobacterium nucleatum (Fn) and Porphyromonas gingivalis (Pg) on inflammasomes and their regulators in human gingival fibroblasts (HGFs) in vitro. HGFs were exposed to Fn and Pg alone or in combination for 24hr at a multiplicity of infection of 100, ±30min exposure with 5mM adenosine triphosphate (ATP) incubation. Gene expression of NLRP3 and AIM2, inflammasome regulatory proteins POP1, CARD16 and TRIM16, and inflammasome components ASC and CASPASE 1, and IL-1β, were evaluated by RT-PCR. Pro- and mature IL-1β levels were monitored intracellularly by immunocytochemistry and extracellularly by ELISA. Fn+ATP significantly upregulated NLRP3, AIM2, IL-1β, ASC, and CASPASE 1; however, it downregulated POP1 and TRIM16. Pg+ATP downregulated NLRP3, ASC, POP1, but upregulated IL-1β and CARD16. Pg+Fn+ATP significantly upregulated AIM2, IL-1β and CARD16, and downregulated POP1, TRIM16, and CASPASE 1. Pg+ATP exposure significantly increased pro- and mature IL-1β production. Bacterial exposure with ATP may deregulate IL-1β by dysregulating inflammasomes and their regulators in HGFs.

Proteolysis of Gingival Keratinocyte Cell Surface Proteins by Gingipains Secreted From Porphyromonas gingivalis - Proteomic Insights Into Mechanisms Behind Tissue Damage in the Diseased Gingiva.

Porphyromonas gingivalis, the main etiologic agent of periodontitis, secretes cysteine proteases named gingipains. HRgpA and RgpB gingipains have Arg-specificity, while Kgp gingipain is Lys-specific. Together they can cleave an array of proteins and importantly contribute to the development of periodontitis. In this study we focused on gingipain-exerted proteolysis at the cell surface of human gingival epithelial cells [telomerase immortalized gingival keratinocytes (TIGK)] in order to better understand the molecular mechanisms behind tissue destruction in periodontitis. Using mass spectrometry, we investigated the whole sheddome/degradome of TIGK cell surface proteins by P. gingivalis strains differing in gingipain expression and by purified gingipains, and performed the first global proteomic analysis of gignpain proteolysis at the membrane. Incubation of TIGK cells with P. gingivalis resulted in massive degradation of proteins already at low multiplicity of infection, whereas incubating cells with purified gingipains resulted in more discrete patterns, indicative of a combination of complete degradation and shedding of membrane proteins. Most of the identified gingipain substrates were molecules involved in adhesion, suggesting that gingipains may cause tissue damage through cleavage of cell contacts, resulting in cell detachment and rounding, and consequently leading to anoikis. However, HRgpA and RgpB gingipains differ in their mechanism of action. While RgpB rapidly degraded the proteins, HRgpA exhibited a much slower proteolysis indicative of ectodomain shedding, as demonstrated for the transferrin receptor protein 1 (TFRC). These results reveal a molecular underpinning to P. gingivalis-induced tissue destruction and enhance our knowledge of the role of P. gingivalis proteases in the pathobiology of periodontitis. Proteomics data are available via ProteomeXchange with identifier PXD015679.

Awareness of Periodontal Medicine among Medical Students at a Tertiary Care Center

Introduction: Tissue destruction of supporting periodontal tissues is mediated by an overreactive immune inflammatory response to bacteria in the subgingival environment. Tissue destruction in periodontitis occurs by the stimulatory action of pro inflammatory cytokines and proteolytic enzymes released by neutrophils, macrophages, and the action of bone resorption mediators, all of which are being regulated by B and T cells. Periodontitis act as a focus of infection and bacteria metastases through blood stream to various vital organs like heart, lungs, joints and amniotic fluid.&#x0D; Objective: To assess the awareness of periodontal medicine among medical students at a tertiary care center in Kathmandu.&#x0D; Methods: A total of 115 subjects were taken for the present study. Data was collected using a questionnaire which included questions used to assess the knowledge about periodontal diseases and its possible effects on systemic conditions.&#x0D; Results: Out of the total participants, 58 (50.4%) said that periodontal disease was not related to coronary heart diseases. Only 14 (12.2%) had an idea about the association of pre-term birth and periodontitis. While 86 (74.8%) knew the impact of diabetes on periodontium, only 34 (29.6%) said that there was an association between periodontitis and hospital acquired pneumonia.&#x0D; Conclusion: Knowledge about the association of periodontal disease with various systemic conditions is not satisfactory among the various medical students of this hospital.

Granulocyte colony stimulating factor (G-CSF) regulates neutrophils infiltration and periodontal tissue destruction in an experimental periodontitis

Although granulocyte colony-stimulating factor(G-CSF) has pathogenic roles in several immune inflammatory diseases, its role in periodontitis has not been investigated. Here we detected local expression of G-CSF using public datasets in the Gene Expression Omnibus (GEO) database, and immune cell infiltration into gingival tissue was estimated based on single-sample gene set enrichment analysis (ssGSEA). G-CSF expression and neutrophil infiltration were also confirmed by human gingival biopsies analysis. Moreover, anti-G-CSF neutralizing antibody was locally administrated to investigate the effects of G-CSF neutralization on neutrophils infiltration and periodontal tissue destruction in periodontitis mice model. Two public datasets (GSE10334 and GSE16134), which included 424 patients with periodontitis and 133 health controls, were used in the analysis. Markedly increased immune cell infiltration and G-CSF expression in gingival tissues were found in the periodontitis group as compared to the control group. The higher expression of G-CSF was correlated with higher infiltration of immune cells, especially with neutrophil infiltration. Analysis of gingival biopsies further confirmed high neutrophil infiltration and G-CSF expression. In addition, anti-G-CSF antibody-treated mice with periodontitis showed significantly reduced alveolar bone resorption and neutrophil infiltration when compared with periodontitis mice treated with isotype control antibody. Also, anti-G-CSF antibody treatment significantly reduced mRNA expression of CXC chemokines (CXCL1, CXCL2 and CXCL3), interleukin 1β (IL-1β), IL-6, matrix metalloproteinases 9, receptor activator of nuclear factor κB ligand/osteoprotegerin (RANKL/OPG) ratio and osteoclasts number in periodontal tissues. In summary, neutrophil infiltration and G-CSF expression levels were significantly increased in inflamed gingival tissues. G-CSF neutralization in periodontal inflammation could alleviate neutrophil infiltration and periodontal tissue destruction in experimental periodontitis.

Porphyromonas gingivalis lipopolysaccharide promotes T- helper 17 cell differentiation from human CD4+ naïve T cells via toll-like receptor-2 in vitro

ObjectivesThe persistence of T-helper 17 (Th17) cells has been shown to support chronic inflammation and mediate tissue destruction in periodontitis. However, little is known regarding the underlying mechanisms that regulate Th17 cell differentiation in the periodontal inflammatory context. The objective of this study was to explore the possible effect and mechanism of lipopolysaccharide (LPS) from Porphyromonas gingivalis on Th17 cell differentiation. MethodsActivated human CD4+CD45RA+ naïve T cells were stimulated with different doses of LPS from virulent and avirulent P. gingivalis strains combined with Th17 driven cytokines in vitro. Flow cytometry was used to analyze the differentiation ratio of Th17 cells. IL-17A protein expression and IL-17, retinoid-related orphan receptor C (RORC) and toll-like receptor 2 (TLR2) mRNA transcription were analysed by ELISA and real-time qPCR, respectively. The role of TLR2 in Th17 cell differentiation was further confirmed by TLR2 blocking assay. ResultsLPS from P. gingivalis (Pg-LPS) up-regulated Th17 cell differentiation ratios, expression of IL-17 and RORC mRNA, and IL-17 concentration in culture supernatant, with 0.1 μg/mL LPS from the virulent P. gingivalis strain being the most effectively. Furthermore, Pg-LPS also up-regulated expression of TLR2 on T cells during Th17 differentiation, and the differentiation was attenuated by treatment with TLR2 antibody. ConclusionsThese results suggest that Pg-LPS promotes Th17 cell differentiation in vitro, and TLR2 signalling may be involved in this process. LPS from the virulent P. gingivalis strain up-regulated Th17 cell differentiation more effectively, which may be associated with the pathogenicity of different P. gingivalis strains.

THE INFLUENCE OF THYROID HORMONES ON PROTEIN OXIDATIVE MODIFICATION IN CASE OF EXPERIMENTAL PERIODONTITIS

Introduction. The inflammatory-dystrophic process in periodontium is accompanied by its hypoxia, which causes the activation of free radical oxidation processes. Tissue destruction in periodontal diseases is considered to be the result of an altered inflammatory/immune response to microbial plaque and involves massive release of neutrophils, reactive oxygen species and enzymes.&#x0D; The aim of the study – to establish the protein oxidative modification in blood and periodontium in case of periodontitis combined with hyper- and hypothyroidism in rats.&#x0D; Research Methods. Experimental studies were carry out on 48 mature male, nonliner, white rats, which were divided into the following groups: І – control animals; ІІ – animals with periodontitis; ІІІ – animals with periodontitis combined with hyperthyroidism; IV – animals with periodontitis combined with hypothyroidism. Protein oxidative modification (POM) was determined in blood serum and periodontium homogenate by the method of I.F. Meschyshyn.&#x0D; Results and Discussion. The results of our studies showed that the intensity of the processes of protein oxidative modification was significantly increased in animals of all experimental groups vs control group. The content of aldehyde- and ketone derivatives of the alkali nature changed more pronounced than the content of aldehyde and ketone derivatives of neutral nature.&#x0D; Conclusions. Thus, the experimental periodontitis is accompanied by a marked increase in the intensity of the protein oxidative modifications both in the homogenate of periodontal tissues and in the blood serum. Imbalance of thyroid hormones increases oxidative stress in experimental periodontitis, especially pronounced in hyperthyroidism.

Pattern recognition receptor polymorphisms in early periodontitis.

Even though bacteria trigger inflammation, most of the tissue destruction in periodontitis is due to the host inflammatory response. In addition to immunological events that drive development of early periodontitis, numerous environmental factors like genetics and smoking play a role. We investigated whether the carriage of selected single nucleotide polymorphisms (SNP) of toll-like receptors (TLR), NOD-like receptors (NLR) and RIG-I-like receptors (RLR) was associated with the diagnosis of early periodontitis in a case-control study. Adolescents with positive (n=87) and negative (n=73) diagnosis for periodontitis had blood samples taken. All participants were genotyped for 42 SNP in the genes encoding TLR1-10, NOD1-2, DDX58, and IFIH1 using multiplex assays. Associations between SNP and periodontitis diagnosis were tested. TLR1-rs5743611 showed protective effect for periodontitis (CC versus GG and GC, P=0.01, odds ratio [OR] 0.10, 95% confidence interval [CI] 0.01-0.78). Carriage of the TLR4-rs7873784 was associated with higher odds for periodontitis (GG versus CC and GC, P=0.05, OR 2.30, 95% CI 1.00-5.63; GG versus GC, P=0.05, OR 2.46, 95% CI 1.01-5.99). In male participants, reduced susceptibility to periodontitis was observed in carriers of TLR7-rs3853839 (CC versus GG and CG, P=0.02, OR 0.30, 95% CI 0.11-0.85) and TLR8-rs3764879 (CC versus GG and CG, P=0.02, OR 0.31, 95% CI 0.12-0.82). Associations were maintained after adjustments for sex, smoking habits, and mother´s education. This study demonstrated an association between TLR1-rs5743611, TLR4-rs7873784, TLR7-rs3853839, and TLR8-rs3764879 and susceptibility to periodontitis in adolescents.

Gene expression analysis of neuropeptides in oral mucosa during periodontal disease in non-human primates.

Neuropeptides (NPs) are innate pivotal regulators of the immunoinflammatory response. Nevertheless, their role in the pathogenesis of periodontal disease remains unknown. Changes in gene expression of 10 NPs and 16 NP receptors (NPRs) coincident with the initiation, progression, and resolution of periodontitis were determined. The ligature-induced periodontitis model was used in rhesus monkeys (n=18). Gingival tissue samples were taken at baseline (preligatures), at 2weeks and at 1 month (initiation), and at 3 months (progression) postligation. Ligatures were removed and samples taken 2 months later (resolution). Total RNA was isolated from tissues and NP/NPR gene expression microarray analysis was performed. Gene expression changes were validated by quantitative polymerase chain reaction and immunohistochemistry. Unexpectedly, the expression of pro-inflammatory NPs/NPRs did not change during periodontitis or with resolution. However, increased expression of the anti-inflammatory NPs adrenomedullin (ADM) and galanin (GAL), and the NPRs calcitonin receptor-like (CALCRL) and receptor activity-modifying protein-2 and -3 (RAMP2 and RAMP3) were observed during initiation and progression of disease. The expression of the same NPs/NPRs exhibited a significant positive correlation with both molecular (interleukin-1ß, matrix mettaloproteinase-9, and receptor activator of nuclear factor-kappa B ligand) and clinical measures of gingival inflammation and tissue destruction. Initiation and progression of periodontitis involve significant overexpression of ADM, GAL, CALCRL, RAMP2, and RAMP3. These anti-inflammatory NPs/NPRs could play a role in the unresolved infection and inflammation that normally drives tissue destruction in periodontitis. Both ADM and GAL potentially are new candidates to consider as biomolecules associated with periodontal disease activity.

Level of Interleukin-17 in Gingival Crevicular Fluid of Patients with Chronic Periodontitis

Aim: Interleukin-17 (IL-17) is a proinflammatory cytokine that plays an important role in inflammation and tissue destruction in periodontal disease. This study aimed to assess the level of IL-17 in gingival crevicular fluid (GCF) of patients with chronic periodontitis (CP) and healthy controls. Materials and methods: This case-control study was performed on 30 patients with CP (53 males, 47 females, mean age of 37.2 ± 5.95 years) and 30 healthy controls (53 males, 47 females, mean age of 30.63 ± 5.22 years). The GCF was collected using paper points. A paper point was inserted into the pocket and remained there for 30 seconds. It was then placed in a sterile tube containing 300 µL of phosphate buffered saline and stored at-70° C. Level of IL-17 was measured using enzyme-linked immune sorbent assay (ELISA). The level of IL-17 was compared between the two groups using independent sample t-test at 0.05 level of significance. Results: The mean GCF level of IL-17 was 53.46 pg/L in CP patients and 38.1 pg/L in healthy controls. This difference was statistically significant (p = 0.025). Conclusion: The CP patients had significantly higher GCF level of IL-17 compared to healthy controls. Clinical significance: The finding of this study highlight the role of IL-17 in the pathogenesis of periodontal disease. Within the limitations of the present study, it may be suggested that measurement of GCF level of IL-17 can serve as a bioindicator of periodontal destruction and gingival inflammation. © 2018, Jaypee Brothers Medical Publishers (P) Ltd. All rights reserved.