Increased plasma levels epithelial cell-derived neutrophil-activating peptide 78/CXCL5 in periodontitis patients undergoing supportive therapy

The role of periodontitis in cancer development, with a focus on oral cancers

Periodontitis is a severe gum infection that begins as gingivitis and can lead to gum recession, bone loss, and tooth loss if left untreated. It is primarily caused by bacterial infection, which triggers inflammation and the formation of periodontal pockets. Notably, periodontitis is associated with systemic health issues and has been linked to heart disease, diabetes, respiratory diseases, adverse pregnancy outcomes, and cancers. Accordingly, the presence of chronic inflammation and immune system dysregulation in individuals with periodontitis significantly contributes to the initiation and progression of various cancers, particularly oral cancers. These processes promote genetic mutations, impair DNA repair mechanisms, and create a tumor-supportive environment. Moreover, the bacteria associated with periodontitis produce harmful byproducts and toxins that directly damage the DNA within oral cells, exacerbating cancer development. In addition, chronic inflammation not only stimulates cell proliferation but also inhibits apoptosis, causes DNA damage, and triggers the release of pro-inflammatory cytokines. Collectively, these factors play a crucial role in the progression of cancer in individuals affected by periodontitis. Further, specific viral and bacterial agents, such as hepatitis B and C viruses, human papillomavirus (HPV), Helicobacter pylori (H. pylori), and Porphyromonas gingivalis, contribute to cancer development through distinct mechanisms. Bacterial infections have systemic implications for cancer development, while viral infections provoke immune and inflammatory responses that can lead to genetic mutations. This review will elucidate the link between periodontitis and cancers, particularly oral cancers, exploring their underlying mechanisms to provide insights for future research and treatment advancements.

Thyrotropin inhibits osteogenic differentiation of human periodontal ligament stem cells

BACKGROUND AND OBJECTIVE

Periodontal ligament stem cells (PDLSCs) are derived from the periodontal ligament and have the characteristics of pluripotent differentiation, including osteogenesis, and are one of the important seed cells in oral tissue engineering. Thyrotropin (TSH) has been shown to regulate bone metabolism independently of thyroid hormone, including the fate of osteoblasts and osteoclasts, but whether it affects osteogenic differentiation of PDLSCs is unknown.

MATERIALS AND METHODS

PDLSCs were isolated and cultured from human periodontal ligament and grown in osteogenic medium (containing sodium β-glycerophosphate, ascorbic acid, and dexamethasone). Recombinant human TSH was added to the culture medium. Osteogenic differentiation of PDLSCs was assessed after 14 days by staining with alkaline phosphatase and alizarin red and by detection of osteogenic differentiation genes. Differentially expressed genes (DEGs) in PDLSCs under TSH were detected by high-throughput sequencing. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyzed the biological functions and signaling pathways involved in DEGs.

RESULTS

We found that osteogenic differentiation of PDLSCs was significantly inhibited in the presence of TSH: including decreased calcium nodule formation, decreased alkaline phosphatase levels, and decreased collagen synthesis. Using high-throughput sequencing, we found changes in the expression of some osteogenesis-related genes, which may be the reason that TSH inhibits osteogenic differentiation of PDLSCs.

CONCLUSION

Unless TSH is ≥10 mU/L, patients with subclinical hypothyroidism usually do not undergo thyroxine supplementation therapy. However, in this work, we found that elevated TSH inhibited the osteogenic differentiation of PDLSCs. Therefore, correction of TSH levels in patients with subclinical hypothyroidism may be beneficial to improve orthodontic, implant, and periodontitis outcomes in these patients.

CXCL5, CXCL8, and CXCL10 regulation by bacteria and mechanical forces in periodontium

OBJECTIVE

The aim of the present study was to evaluate the expressions of CXCL5, CXCL8, and CXCL10 in periodontal cells and tissues in response to microbial signals and/or biomechanical forces.

METHODS

Human gingival biopsies from inflamed and healthy sites were used to examine the chemokine expressions and protein levels by real-time PCR and immunohistochemistry. The chemokines were also investigated in gingival biopsies from rats submitted to experimental periodontitis and/or tooth movement. Furthermore, chemokine levels were determined in human periodontal fibroblasts stimulated by the periodontopathogen Fusobacterium nucleatum and/or constant tensile forces (CTS) by real-time PCR and ELISA. Additionally, gene expressions were evaluated in periodontal fibroblasts exposed to F. nucleatum and/or CTS in the presence and absence of a MAPK inhibitor by real-time PCR.

RESULTS

Increased CXCL5, CXCL8, and CXCL10 levels were observed in human and rat gingiva from sites of inflammation as compared with periodontal health. The rat experimental periodontitis caused a significant (p<0.05) increase in alveolar bone resorption, which was further enhanced when combined with tooth movement. In vitro, F. nucleatum caused a significant upregulation of CXCL5, CXCL8, and CXCL10 at 1 day. Once the cells were exposed simultaneously to F. nucleatum and CTS, the chemokines regulation was significantly enhanced. The transcriptional findings were also observed at protein level. Pre-incubation with the MEK1/2 inhibitor significantly (p<0.05) inhibited the stimulatory actions of F. nucleatum either alone or in combination with CTS on the expression levels of CXCL5, CXCL8, and CXCL10 at 1d.

CONCLUSIONS

Our data provide original evidence that biomechanical strain further increases the stimulatory actions of periodontal bacteria on the expressions of these chemokines. Therefore, biomechanical loading in combination with periodontal infection may lead to stronger recruitment of immunoinflammatory cells to the periodontium, which might result in an aggravation of periodontal inflammation and destruction.

Periodontitis and oral cancer - current concepts of the etiopathogenesis

Gingival tissues are attacked by oral pathogens which can induce inflammatory reactions. The immune-inflammatory responses play essential roles in the patient susceptibility to periodontal diseases. There is a wealth of evidence indicating a link between chronic inflammation and risk of malignant transformation of the affected oral epithelium. Periodontitis is associated with an increased risk of developing chronic systemic conditions including autoimmune diseases and different types of cancers. Besides, some risk factors such as smoking, alcohol consumption and human papilloma virus have been found to be associated with both periodontitis and oral cancer. This review article aimed to study the current concepts in pathogenesis of chronic periodontitis and oral cancer by reviewing the related articles.

Antibiofilm peptides against oral biofilms

The oral cavity is a major entry point for bacteria and other microorganisms. Oral biofilms are formed by mixed communities of microorganisms embedded in an exopolysaccharide matrix. Biofilms forming on dental hard or soft tissue are the major cause of caries and endodontic and periodontal disease. Human oral biofilms exhibit high resistance to antimicrobial agents. Antibiofilm peptides constitute a diverse class of host-defense molecules that act to combat invasion and infection with biofilms. Different in vitro and in vivo biofilm models with quantitative analysis have been established to provide predictable platforms for the evaluation of the antibiofilm effect of oral antibiofilm peptides. These peptides have engendered considerable interest in the past decades as potential alternatives to traditional disinfecting agents due to their ability to target bacterial biofilms specifically, leading to the prevention of biofilm formation and destruction of pre-existing biofilms by Gram-positive and -negative bacterial pathogens and fungi. At the same time, challenges associated with the application of these antibiofilm peptides in dental practice also exist. The production of effective, nontoxic, and stable antibiofilm peptides is desired in both academic and industrial fields. This review focuses on the antibiofilm properties of current synthetic peptides and their application in different areas of dentistry.

The Influence of Glycated Hemoglobin on the Cross Susceptibility Between Type 1 Diabetes Mellitus and Periodontal Disease

BACKGROUND

Periodontal disease is a major complication of type 1 diabetes mellitus (T1DM). The aim of the present study is to investigate the relationship between glycated hemoglobin and circulating levels of interleukin (IL)-6, IL-8, and C-X-C motif chemokine ligand 5 (CXCL5) in non-smoking patients suffering from T1DM, with and without periodontitis. In addition, to determine the effect of advanced glycation end products (AGE) in the presence and absence of Porphyromonas gingivalis lipopolysaccharide (LPS) on IL-6, IL-8, and CXCL5 expression by THP-1 monocytes and OKF6/TERT-2 cells.

METHODS

There were 104 participants in the study: 19 healthy volunteers, 23 patients with periodontitis, 28 patients with T1DM, and 34 patients with T1DM and periodontitis. Levels of blood glucose/glycated hemoglobin (International Federation of Clinical Chemistry [IFCC]) were determined by high-performance liquid chromatography. Levels of IL-6, IL-8, and CXCL5 in plasma were determined by enzyme-linked immunosorbent assay (ELISA). In vitro stimulation of OKF6/TERT-2 cells and THP-1 monocytes was performed with combinations of AGE and P. gingivalis LPS. Changes in expression of IL-6, IL-8, and CXCL5 were monitored by ELISA and real-time polymerase chain reaction.

RESULTS

Patients with diabetes and periodontitis had higher plasma levels of IL-8 than patients with periodontitis alone. Plasma levels of IL-8 correlated significantly with IFCC units, clinical probing depth, and attachment loss. AGE and LPS, alone or in combination, stimulated IL-6, IL-8, and CXCL5 expression in both OKF6/TERT-2 cells and THP-1 monocytes.

CONCLUSIONS

Elevated plasma levels of IL-8 potentially contribute to the cross-susceptibility between periodontitis and T1DM. P. gingivalis LPS and AGE in combination caused significantly greater expression of IL-6, IL-8, and CXCL5 from THP-1 monocytes and OKF6/TERT-2 cells than LPS alone.

Chemokine function in periodontal disease and oral cavity cancer

The chemotactic cytokines, or chemokines, comprise a superfamily of polypeptides with a wide range of activities that include recruitment of immune cells to sites of infection and inflammation, as well as stimulation of cell proliferation. As such, they function as antimicrobial molecules and play a central role in host defenses against pathogen challenge. However, their ability to recruit leukocytes and potentiate or prolong the inflammatory response may have profound implications for the progression of oral diseases such as chronic periodontitis, where tissue destruction may be widespread. Moreover, it is increasingly recognized that chronic inflammation is a key component of tumor progression. Interaction between cancer cells and their microenvironment is mediated in large part by secreted factors such as chemokines, and serves to enhance the malignant phenotype in oral and other cancers. In this article, we will outline the biological and biochemical mechanisms of chemokine action in host–microbiome interactions in periodontal disease and in oral cancer, and how these may overlap and contribute to pathogenesis.

Matrix metalloproteinases regulate extracellular levels of SDF-1/CXCL12, IL-6 and VEGF in hydrogen peroxide-stimulated human periodontal ligament fibroblasts

Periodontitis is a highly prevalent infectious disease characterized by the progressive inflammatory destruction of tooth-supporting structures, leading to tooth loss. The underling molecular mechanisms of the disease are incompletely understood, precluding the development of more efficient screening, diagnostic and therapeutic approaches. We investigated the interrelation of three known effector mechanisms of the cellular response to periodontal infection, namely reactive oxygen species (ROS), matrix metalloproteinases (MMPs) and cytokines in primary cell cultures of human periodontal ligament fibroblast (hPDLF). We demonstrated that ROS increase the activity/levels of gelatinolytic MMPs, and stimulate cytokine secretion in hPDLF. Additionally, we proved that MMPs possesses immune modulatory capacity, regulating the secreted levels of cytokines in ROS-stimulated hPDLF cultures. This evidence provides further insight in the molecular pathogenesis of periodontitis, contributing to the future development of more effective therapies.

Development of an in vitro periodontal biofilm model for assessing antimicrobial and host modulatory effects of bioactive molecules

Background

Inflammation within the oral cavity occurs due to dysregulation between microbial biofilms and the host response. Understanding how different oral hygiene products influence inflammatory properties is important for the development of new products. Therefore, creation of a robust host-pathogen biofilm platform capable of evaluating novel oral healthcare compounds is an attractive option. We therefore devised a multi-species biofilm co-culture model to evaluate the naturally derived polyphenol resveratrol (RSV) and gold standard chlorhexidine (CHX) with respect to anti-biofilm and anti-inflammatory properties.

Methods

An in vitro multi-species biofilm containing S. mitis, F. nucleatum, P. gingivalis and A. actinomycetemcomitans was created to represent a disease-associated biofilm and the oral epithelial cell in OKF6-TERT2. Cytotoxicity studies were performed using RSV and CHX. Multi-species biofilms were either treated with either molecule, or alternatively epithelial cells were treated with these prior to biofilm co-culture. Biofilm composition was evaluated and inflammatory responses quantified at a transcriptional and protein level.

Results

CHX was toxic to epithelial cells and multi-species biofilms at concentrations ranging from 0.01-0.2%. RSV did not effect multi-species biofilm composition, but was toxic to epithelial cells at concentrations greater than 0.01%. In co-culture, CHX-treated biofilms resulted in down regulation of the inflammatory chemokine IL-8 at both mRNA and protein level. RSV-treated epithelial cells in co-culture were down-regulated in the release of IL-8 protein, but not mRNA.

Conclusions

CHX possesses potent bactericidal properties, which may impact downstream inflammatory mediators. RSV does not appear to have bactericidal properties against multi-species biofilms, however it did appear to supress epithelial cells from releasing inflammatory mediators. This study demonstrates the potential to understand the mechanisms by which different oral hygiene products may influence gingival inflammation, thereby validating the use of a biofilm co-culture model.

Matrix metalloproteinases and myeloperoxidase in gingival crevicular fluid provide site-specific diagnostic value for chronic periodontitis

AIM

To identify the diagnostic accuracy of gingival crevicular fluid (GCF) candidate biomarkers to discriminate periodontitis from the inflamed and healthy sites, and to compare the performance of two independent matrix metalloproteinase (MMP)-8 immunoassays.

MATERIALS AND METHODS

Cross sectional study. GCF (N = 58 sites) was collected from healthy, gingivitis and chronic periodontitis volunteers and analysed for levels of azurocidin, chemokine ligand 5, MPO, TIMP-1 MMP-13 and MMP-14 by ELISA or activity assays. MMP-8 was assayed by immunofluorometric assay (IFMA) and ELISA. Statistical analysis was performed using linear mixed-effects models and Bayesian statistics in R and Stata V11.

RESULTS

MMP-8, MPO, azurocidin and total MMP-13 and MMP-14 were higher in periodontitis compared to gingivitis and healthy sites (p < 0.05). A very high correlation between MPO and MMP-8 was evident in the periodontitis group (r = 0.95, p < 0.0001). MPO, azurocidin and total levels of MMP-8, MMP-13 and MMP-14 showed high diagnostic accuracy (≥0.90), but only MMP-8 and MPO were significantly higher in the periodontitis versus gingivitis sites. MMP-8 determined by IFMA correlated more strongly with periodontal status and showed higher diagnostic accuracy than ELISA.

CONCLUSIONS

MPO and collagenolytic MMPs are highly discriminatory biomarkers for site-specific diagnosis of periodontitis. The comparison of two quantitative MMP-8 methods demonstrated IFMA to be more accurate than ELISA.