Hepatocyte growth factor levels in the saliva and gingival crevicular fluid in smokers with periodontitis

Necrotizing Gingivitis: Microbial Diversity and Quantification of Protein Secretion in Necrotizing Gingivitis

Necrotizing gingivitis (NG) is a necrotizing periodontal disease that differs from chronic gingivitis (CG). To date, both the microbiological causes and the involved host cytokine response of NG still remain unclear. Here, we investigated corresponding interdental plaque and serum samples from two groups of Chinese patients with CG (n = 21) or NG (n = 21). The microbiota were studied by 16S rRNA Illumina MiSeq sequencing of the microbial metagenome and by assessing quantitatively the abundance of the phylum Bacteroidetes, the genus Prevotella and the species T. forsythia, P. endodontalis, and P. gingivalis using fluorescence in situ hybridization (FISH). With respect to the associated host response, the levels of 30 inflammatory mediators were quantified by multiplex immunoassay analysis. Differential microbial abundance analysis of the two disease groups revealed at the phylum level that Proteobacteria accounted for 67% of the differentially abundant organisms, followed by organisms of Firmicutes (21%) and Actinobacteria (9%). At the species level, significant differences in abundance were seen for 75 species of which 58 species were significantly more abundant in CG patients. Notably, the FISH analysis revealed that Bacteroidetes was the most prevalent phylum in NG. The multiplex cytokine assay showed significant quantitative differences between the disease groups for eight analytes (GM–CSF, G–CSF, IFN–α, IL–4, IL–13, TNF–α, MIG, and HGF). The G–CSF was found to be the most significantly increased inflammatory protein marker in NG. The next-generation sequencing (NGS) data supported the understanding of NG as a multi-microbial infection with distinct differences to CG in regard to the microbial composition.

Local administration of anti-hepatocyte growth factor-neutralizing antibody reverts naturally occurring periodontitis

OBJECTIVES

Periodontitis is a chronic inflammatory process associated with the loss of tooth-supporting tissue. The imbalance of epithelial-mesenchymal signaling is considered to drive disease progression, and hepatocyte growth factor (HGF) is one of the main mediators of this interaction. The aim of this study was to validate the role of HGF in the pathogenesis of periodontitis and to evaluate the effects of anti-HGF neutralizing antibodies.

METHODS

Gingival tissues from cynomolgus monkeys, which naturally develop severe periodontitis, were isolated to establish an in vitro periodontitis model. Periodontitis-affected monkeys were treated by gingival injection of anti-HGF neutralizing antibodies. The therapeutic effects were documented by clinical examination (probing depth and bleeding on probing), histological examination of tissue, and reevaluation of gingival fibroblasts in the in vitro model.

RESULTS

Periodontitis-affected monkeys contain periodontitis-associated fibroblasts (PAFs) with a pro-inflammatory phenotype that induced pronounced collagen degradation in vitro. This degradation was effectively inhibited by anti-HGF-neutralizing antibodies. Locally administered anti-HGF antibody to monkey gingiva clinically improved the severity of periodontitis. This was also reflected in the tissue histology with lower inflammatory cell infiltrates in treated gingiva than in non-treated gingiva. Moreover, fibroblasts isolated from anti-HGF-treated gingiva demonstrated reduced collagen degradation capacity.

CONCLUSIONS

Our study confirmed the central role of HGF in the pathogenesis of severe periodontitis in relevant in vitro and in vivo models. The positive effect of anti-HGF treatment provides a strong rationale for the use of anti-HGF-neutralizing antibodies for the treatment of human periodontitis.

Metabolic Disturbance and Th17/Treg Imbalance Are Associated With Progression of Gingivitis

Objective

This study sought to explore the role of metabolic disturbance in immunoregulation of gingivitis targeting T helper 17 cells (Th17)/regulatory T cell (Treg).

Materials and Methods

A total of 20 gingivitis patients and 19 healthy volunteers were recruited. Quantitative real time polymerase chain reaction (qRT-PCR) was used to evaluate expression patterns of Forkhead box protein P3 (Foxp3), transforming growth factor-β (TGF-β), retinoid-related orphan receptor-gammat (RORγt) and interleukin 17A (IL-17A) in the peripheral blood lymphocytes of subjects across the two groups. Moreover, the enzyme-linked immunosorbent assay (ELISA) technique was used to detect levels of TGF-β, IL-4, IL-6,TL-10 and L-17A secreted in the plasma as well as the SIgA secreted in saliva. Flow cytometry was used to detect the percentage of CD4⁺CD25⁺ Foxp3⁺Treg cells and the percentage of CD4⁺IL-17A⁺ Th17 cells in whole blood of subjects in both groups. Gas chromatography-mass spectrometry (GC-MS) was employed to analyze the plasma metabolites in the gingivitis patient group. Statistical analysis was applied to determine whether the plasma metabolites and related metabolic pathways significantly differed between gingivitis patients and healthy controls. Ingenuity pathway analysis (IPA) was employed to identify the potential relation between the metabolites and the Th17 and Treg related pathway.

Results

The percentages of CD4⁺IL17A⁺Th17 cells and IL-17 significantly increased in the peripheral blood in the gingivitis group. Moreover, the upregulation of IL-17A mRNA and RORγt mRNA were also found in the gingivitis group. However, the percentage of CD4⁺CD25⁺ Foxp3⁺Treg cells and Foxp3 mRNA in the whole blood did not significantly change. However, TGF-β mRNA as well as TGF-β, IL-4, IL-6, IL-10 in the periperial blood and SIgA in the saliva were higher in the gingivitis group. Notably, that the ratio of Th17/Treg cells was significantly increased during peripheral circulation. Furthermore, we identified 18 different metabolites which were differentially expressed in plasma between the gingivitis and healthy control groups. Notably, the levels of cholesterol, glycerol 1-octadecanoate, d-glucose, uric acid, cyclohexaneacetic acid, 3-pyridine, tryptophan, and undecane 2,4-dimethyl were significantly up-regulated. whereas the levels of lactic acid, glycine, linoleic acid, monopalmitic acid, glycerol, palmitic acid, pyruvate, 1-(3-methylbutyl)-2,3,4,6-tetramethylbenzene, 1 5-anhydro d-altrol, and boric acid were down-regulated in the gingivitis group, relative to healthy controls. IPA showed that these metabolites are connected to IL17 signaling, TGF-B signaling, and IL10 signaling, which are related closely to Th17 and Treg pathway.

Conclusion

Overall, these results showed that disturbance to glycolysis as well as amino and fatty acid metabolism are associated with Th17/Treg balance in gingivitis. Impaired immunometabolism may influence some periodontally involved systemic diseases, hence it is a promising strategy in targeted development of treatment therapies.

Central Regulatory Role of Cytokines in Periodontitis and Targeting Options

BACKGROUND

Periodontitis is an immune-inflammatory disease that leads to the progressive destruction of bone and connective tissue in the periodontal area. The cytokine network plays a primary role in tissue homeostasis, the recruitment of immune cells to control the pathogenic impact and the regulation of osteoclastic function, thus modulating the intensity and duration of the immune response. This review provides an update on the main cytokines implicated in the pathogenesis and progression of periodontitis and their targeting potential in order to enrich current treatment options.

METHODS

A structured search of bibliographic databases (PubMed, MEDLINE, Scopus) was performed for peer-reviewed cytokine studies focused on periodontitis the last ten years. A qualitative content analysis was performed in screened papers and a critical discussion of main findings is provided.

RESULTS

An altered cytokine profile has been detected in periodontitis patients and the interplay of pro-inflammatory and/or anti-inflammatory cytokines has been associated with disease pathogenesis. Among the most prominent pro-inflammatory cytokines, TNF-α, IL-1β, IL-17, IL-6 and the chemokines CXCL-6, CXCL-8 are overexpressed in periodontitis patients and correlate with disease progression. On the other hand, the anti-inflammatory IL-4 and IL- 11 levels are reduced while IL-12 and IFN-γ expression play a dual role in periodontal disease. Current periodontitis treatment strategies include selective antibiotics, antimicrobial photodynamic therapy and probiotics, which can modulate the cytokine network and when applied in combination with specific anti-cytokine agents can exert additional beneficial effects.

CONCLUSION

It is evident that cytokines play a central regulatory role in the inflammatory process and immune cell response that underlies bone destruction in periodontitis. Specific cytokine targeting should be considered as a complementary therapeutic scheme to current periodontal management.

Targeting hepatocyte growth factor in epithelial-stromal interactions in an in vitro experimental model of human periodontitis

Periodontitis is a chronic inflammatory disease leading to progressive connective tissue degradation and loss of the tooth-supporting bone. Clinical and experimental studies suggest that hepatocyte growth factor (HGF) is involved in the dysregulated fibroblast–epithelial cell interactions in periodontitis. The aim of this study was to explore effects of HGF to impact fibroblast-induced collagen degradation. A patient-derived experimental cell culture model of periodontitis was applied. Primary human epithelial cells and fibroblasts isolated from periodontitis-affected gingiva were co-cultured in a three-dimensional collagen gel. The effects of HGF neutralizing antibody on collagen gel degradation were tested and transcriptome analyses were performed. HGF neutralizing antibody attenuated collagen degradation and elicited expression changes of genes related to extracellular matrix (ECM) and cell adhesion, indicating that HGF signaling inhibition leads to extensive impact on cell–cell and cell–ECM interactions. Our study highlights a potential role of HGF in periodontitis. Antagonizing HGF signaling by a neutralizing antibody may represent a novel approach for periodontitis treatment.

Effect of Nonsurgical Treatment on Salivary HGF Levels in Population with Periodontal Disease: A Quasi-experimental Study

Aim

To assess the effect of nonsurgical treatment on salivary hepatocyte growth factor (sHGF) levels in a population with periodontal disease: a quasi-experimental study.

Methods

Eighty-one patients (aged 30–70 years) were divided into three groups based on the gingival index, probing depth, clinical attachment loss, and radiographic evidence of bone loss: healthy (group I), gingivitis (group II), and chronic periodontitis (group III). Saliva samples were collected from these groups at baseline. At 8 weeks, saliva samples were collected again from group II and group III after the patients went through nonsurgical periodontal treatment. The levels of HGF were estimated using enzyme-linked immunosorbent assay (ELISA). The clinical parameters and HGF levels among all groups were analyzed using a one-way analysis of variance (ANOVA) using SPSS 17 version.

Results

At baseline, the highest mean HGF concentration in saliva was observed for group III (3455.83 ± 1463.44 pg/mL), and the least in group I (469.43 ± 317.13 pg/mL). Following nonsurgical periodontal treatment, the mean HGF concentration decreased significantly in group III and group II (p < 0.05). A significant positive correlation between clinical parameters and HGF levels was also seen (p < 0.05).

Conclusion

HGF concentration showed a positive correlation with the progression of periodontal disease.

Clinical significance

Following nonsurgical periodontal therapy, the levels of HGF decreased significantly, suggesting that HGF could be useful for monitoring the response to periodontal therapy.

How to cite this article

Alreja D, Rao JR, Kataria S, et al. Effect of Nonsurgical Treatment on Salivary HGF Levels in Population with Periodontal Disease: A Quasi-experimental Study. Euroasian J Hepato-Gastroenterol 2020;10(2):51–55.

Comparative evaluation of salivary hepatocyte growth factor in smokers and non-smokers with chronic periodontitis

AIM

Hepatocyte growth factor (HGF) is a multifunctional cytokine with a wide range of actions, and plays a role in periodontal disease (PD) progression. Smoking significantly increases the risk for PD progression. Thus, aim of the present study was to estimate salivary HGF levels of non-smokers and smokers with chronic periodontitis (CP) and to compare its levels before and after therapy.

METHODS

A total of 75 participants were recruited and divided into three groups: group 1 included 25 healthy participants, group 2 included 25 non-smokers with CP, and group 3 included 25 smokers with CP. Salivary HGF levels were estimated by enzyme-linked immunosorbent assay and correlated with clinical parameters before and after treatment.

RESULTS

Salivary HGF levels of non-smokers and smokers with CP were significantly higher than the control group. There was a significant reduction in salivary HGF in smokers and non-smokers with CP after non-surgical periodontal therapy (NSPT).

CONCLUSION

Salivary HGF levels positively correlated with PD progression and smoking status. A significant reduction in HGF levels was seen after NSPT. Thus, within limits, it can be suggested that HGF plays a role in PD progression and can be used as a diagnostic biomarker to detect disease activity. Salivary HGF levels could also be useful to monitor response to periodontal therapy.