Focus on periodontal disease and colorectal carcinoma

Experimental Inoculation of Aggregatibacter actinomycetemcomitans and Streptococcus gordonii and Its Impact on Alveolar Bone Loss and Oral and Gut Microbiomes

Oral bacteria are implicated not only in oral diseases but also in gut dysbiosis and inflammatory conditions throughout the body. The periodontal pathogen Aggregatibacter actinomycetemcomitans (Aa) often occurs in complex oral biofilms with Streptococcus gordonii (Sg), and this interaction might influence the pathogenic potential of this pathogen. This study aims to assess the impact of oral inoculation with Aa, Sg, and their association (Aa+Sg) on alveolar bone loss, oral microbiome, and their potential effects on intestinal health in a murine model. Sg and/or Aa were orally administered to C57Bl/6 mice, three times per week, for 4 weeks. Aa was also injected into the gingiva three times during the initial experimental week. After 30 days, alveolar bone loss, expression of genes related to inflammation and mucosal permeability in the intestine, serum LPS levels, and the composition of oral and intestinal microbiomes were determined. Alveolar bone resorption was detected in Aa, Sg, and Aa+Sg groups, although Aa bone levels did not differ from that of the SHAM-inoculated group. Il-1β expression was upregulated in the Aa group relative to the other infected groups, while Il-6 expression was downregulated in infected groups. Aa or Sg downregulated the expression of tight junction genes Cldn 1, Cldn 2, Ocdn, and Zo-1 whereas infection with Aa+Sg led to their upregulation, except for Cldn 1. Aa was detected in the oral biofilm of the Aa+Sg group but not in the gut. Infections altered oral and gut microbiomes. The oral biofilm of the Aa group showed increased abundance of Gammaproteobacteria, Enterobacterales, and Alloprevotella, while Sg administration enhanced the abundance of Alloprevotella and Rothia. The gut microbiome of infected groups showed reduced abundance of Erysipelotrichaceae. Infection with Aa or Sg disrupts both oral and gut microbiomes, impacting oral and gut homeostasis. While the combination of Aa with Sg promotes Aa survival in the oral cavity, it mitigates the adverse effects of Aa in the gut, suggesting a beneficial role of Sg associations in gut health.

Chronic Stress and Depression in Periodontitis and Peri-Implantitis: A Narrative Review on Neurobiological, Neurobehavioral and Immune-Microbiome Interplays and Clinical Management Implications

Besides the well-known systemic factors for periodontal and peri-implant diseases, additional co-factors, such as chronic stress and depression, may also affect disease onset and progression as well as treatment responsiveness. Neurobiological and neurobehavioral pathogenic links between chronic stress and depression, on the one side, and periodontitis and peri-implantitis, on the other side, which have been little investigated and principally related to necrotizing periodontal disease, have been reviewed, along with their putative interconnections with periodontal immune-microbiome balance. Rising evidence suggest that dysregulated neurobiological and neurobehavioral factors, as well as periodontal immune-microbiome unbalance, all related to chronic stress and depression, may crucially interact and thus represent contributing factors in the genesis and worsening not only of necrotizing periodontal lesions, but also of chronic periodontitis and peri-implantitis. Such potential interconnections may be even more relevant in recurrent and aggressive cases of periodontal and peri-implant disease, which are frequently refractory to therapy, and may, if corroborated, coherently pave the way for personalized prevention and treatment strategies, possibly targeting immune-microbiome unbalance and neurobehavioral factors and focusing on neurobiological ones, especially in chronically stressed and depressed subjects with periodontitis and peri-implantitis.

A Noninvasive Risk Stratification Tool Build Using an Artificial Intelligence Approach for Colorectal Polyps Based on Annual Checkup Data

Colorectal cancer is the leading cause of cancer-related deaths worldwide, and early detection has proven to be an effective method for reducing mortality. The machine learning method can be implemented to build a noninvasive stratifying tool that helps identify patients with potential colorectal precancerous lesions (polyps). This study aimed to develop a noninvasive risk-stratified tool for colorectal polyps in asymptomatic, healthy participants. A total of 20,129 consecutive asymptomatic patients who underwent a health checkup between January 2005 and August 2007 were recruited. Positive relationships between noninvasive risk factors, such as age, Helicobacter pylori infection, hypertension, gallbladder polyps/stone, and BMI and colorectal polyps were observed (p < 0.0001), regardless of sex, whereas significant findings were noted in men with tooth disease (p = 0.0053). A risk stratification tool was developed, for colorectal polyps, that considers annual checkup results from noninvasive examinations. For the noninvasive stratified tool, the area under the receiver operating characteristic curve (AUC) of obese females (males) aged <50 years was 91% (83%). In elderly patients (>50 years old), the AUCs of the stratifying tools were >85%. Our results indicate that the risk stratification tool can be built by using random forest and serve as an efficient noninvasive tool to identify patients requiring colonoscopy.

Periodontal and Peri-Implant Diseases and Systemically Administered Statins: A Systematic Review

Hyperlipidemia is a well-recognized risk factor for cardiovascular disease, which, in turn, acts as a contributory factor in periodontitis development. Periodontitis has been associated with benign tumors and cancers and withseveral disorders, including hyperlipidemia. Correspondingly, periodontal treatment may exert a positive effect on lipid metabolism, although opposite evidence has also been reported. As a counterpart, the therapy for hyperlipidemia, conventionally based on statins, has been proposed to positively affect periodontal conditions, mainly due to statin pleiotropic effects, reducing periodontal inflammation and promoting osseointegration. Therefore, the present systematic review aimed to evaluate, in subjects with untreated periodontitis and peri-implant disease (Population), the effect of routine systemically administered statins (Intervention), compared to non-statin use (Comparison), on periodontal parameters around natural teeth and implants (Outcome). Discordant results were found in periodontal parameters, and the current lack of such data related to peri-implant tissues and to alveolar bone loss highlights the need for further studies on the topic, potentially paving the way for a more comprehensive approach to periodontitis and peri-implantitis management. Indeed, the validation of the beneficial effect provided by systemically delivered statins on periodontal and peri-implant tissues may direct recall scheduling, predict response to therapy and, therefore, guide treatment strategies of periodontal and peri-implant treatments in statin users.

Two-Sample Mendelian Randomization Analysis of Associations Between Periodontal Disease and Risk of Cancer

Background

Observational studies indicate that periodontal disease may increase the risk of colorectal, lung, and pancreatic cancers. Using a 2-sample Mendelian randomization (MR) analysis, we assessed whether a genetic predisposition index for periodontal disease was associated with colorectal, lung, or pancreatic cancer risks.

Methods

Our primary instrument included single nucleotide polymorphisms with strong genome-wide association study evidence for associations with chronic, aggressive, and/or severe periodontal disease (rs729876, rs1537415, rs2738058, rs12461706, rs16870060, rs2521634, rs3826782, and rs7762544). We used summary-level genetic data for colorectal cancer (n = 58 131 cases; Genetics and Epidemiology of Colorectal Cancer Consortium, Colon Cancer Family Registry, and Colorectal Transdisciplinary Study), lung cancer (n = 18 082 cases; International Lung Cancer Consortium), and pancreatic cancer (n = 9254 cases; Pancreatic Cancer Consortia). Four MR approaches were employed for this analysis: random-effects inverse-variance weighted (primary analyses), Mendelian Randomization-Pleiotropy RESidual Sum and Outlier, simple median, and weighted median. We conducted secondary analyses to determine if associations varied by cancer subtype (colorectal cancer location, lung cancer histology), sex (colorectal and pancreatic cancers), or smoking history (lung and pancreatic cancer). All statistical tests were 2-sided.

Results

The genetic predisposition index for chronic or aggressive periodontitis was statistically significantly associated with a 3% increased risk of colorectal cancer (per unit increase in genetic index of periodontal disease; P = .03), 3% increased risk of colon cancer (P = .02), 4% increased risk of proximal colon cancer (P = .01), and 3% increased risk of colorectal cancer among females (P = .04); however, it was not statistically significantly associated with the risk of lung cancer or pancreatic cancer, overall or within most subgroups.

Conclusions

Genetic predisposition to periodontitis may be associated with colorectal cancer risk. Further research should determine whether increased periodontitis prevention and increased cancer surveillance of patients with periodontitis is warranted.

Bacterial community structure alterations within the colorectal cancer gut microbiome

BACKGROUND

Colorectal cancer is a leading cause of cancer-related deaths worldwide. The human gut microbiome has become an active area of research for understanding the initiation, progression, and treatment of colorectal cancer. Despite multiple studies having found significant alterations in the carriage of specific bacteria within the gut microbiome of colorectal cancer patients, no single bacterium has been unequivocally connected to all cases. Whether alterations in species carriages are the cause or outcome of cancer formation is still unclear, but what is clear is that focus should be placed on understanding changes to the bacterial community structure within the cancer-associated gut microbiome.

RESULTS

By applying a novel set of analyses on 252 previously published whole-genome shotgun sequenced fecal samples from healthy and late-stage colorectal cancer subjects, we identify taxonomic, functional, and structural changes within the cancer-associated human gut microbiome. Bacterial association networks constructed from these data exhibited widespread differences in the underlying bacterial community structure between healthy and colorectal cancer associated gut microbiomes. Within the cancer-associated ecosystem, bacterial species were found to form associations with other species that are taxonomically and functionally dissimilar to themselves, as well as form modules functionally geared towards potential changes in the tumor-associated ecosystem. Bacterial community profiling of these samples revealed a significant increase in species diversity within the cancer-associated gut microbiome, and an elevated relative abundance of species classified as originating from the oral microbiome including, but not limited to, Fusobacterium nucleatum, Peptostreptococcus stomatis, Gemella morbillorum, and Parvimonas micra. Differential abundance analyses of community functional capabilities revealed an elevation in functions linked to virulence factors and peptide degradation, and a reduction in functions involved in amino-acid biosynthesis within the colorectal cancer gut microbiome.

CONCLUSIONS

We utilize whole-genome shotgun sequenced fecal samples provided from a large cohort of late-stage colorectal cancer and healthy subjects to identify a number of potentially important taxonomic, functional, and structural alterations occurring within the colorectal cancer associated gut microbiome. Our analyses indicate that the cancer-associated ecosystem influences bacterial partner selection in the native microbiota, and we highlight specific oral bacteria and their associations as potentially relevant towards aiding tumor progression.

Oral and Fecal Microbiome in Molar-Incisor Pattern Periodontitis

In order to improve our understanding on the microbial complexity associated with Grade C/molar-incisor pattern periodontitis (GC/MIP), we surveyed the oral and fecal microbiomes of GC/MIP and compared to non-affected individuals (Control). Seven Afro-descendants with GC/MIP and seven age/race/gender-matched controls were evaluated. Biofilms from supra/subgingival sites (OB) and feces were collected and submitted to 16S rRNA sequencing. Aggregatibacter actinomycetemcomitans (Aa) JP2 clone genotyping and salivary nitrite levels were determined. Supragingival biofilm of GC/MIP presented greater abundance of opportunistic bacteria. Selenomonas was increased in subgingival healthy sites of GC/MIP compared to Control. Synergistetes and Spirochaetae were more abundant whereas Actinobacteria was reduced in OB of GC/MIP compared to controls. Aa abundance was 50 times higher in periodontal sites with PD≥ 4 mm of GC/MIP than in controls. GC/MIP oral microbiome was characterized by a reduction in commensals such as Kingella, Granulicatella, Haemophilus, Bergeyella, and Streptococcus and enrichment in periodontopathogens, especially Aa and sulfate reducing Deltaproteobacteria. The oral microbiome of the Aa JP2-like+ patient was phylogenetically distant from other GC/MIP individuals. GC/MIP presented a higher abundance of sulfidogenic bacteria in the feces, such as Desulfovibrio fairfieldensis, Erysipelothrix tonsillarum, and Peptostreptococcus anaerobius than controls. These preliminary data show that the dysbiosis of the microbiome in Afro-descendants with GC/MIP was not restricted to affected sites, but was also observed in supragingival and subgingival healthy sites, as well as in the feces. The understanding on differences of the microbiome between healthy and GC/MIP patients will help in developing strategies to improve and monitor periodontal treatment.

The Association between Periodontitis and Human Colorectal Cancer: Genetic and Pathogenic Linkage

Periodontitis has been associated with an increased risk of and mortality associated with human colorectal cancer (CRC). Current evidence attributes such an association to the direct and indirect effects of virulence factors belonging to periodontal pathogens, to inflammatory mediators and to genetic factors. The aims of the study were to assess the existence of a genetic linkage between periodontitis and human CRC, to identify genes considered predominant in such a linkage, thus named leader genes, and to determine pathogenic mechanisms related to the products of leader genes. Genes linking periodontitis and CRC were identified and classified in order of predominance, through an experimental investigation, performed via computer simulation, employing the leader gene approach. Pathogenic mechanisms relating to leader genes were determined through cross-search databases. Of the 83 genes linking periodontitis and CRC, 12 were classified as leader genes and were pathogenically implicated in cell cycle regulation and in the immune-inflammatory response. The current results, obtained via computer simulation and requiring further validation, support the existence of a genetic linkage between periodontitis and CRC. Cell cycle dysregulation and the alteration of the immuno-inflammatory response constitute the pathogenic mechanisms related to the products of leader genes.

Treatment of non-erosive reflux disease and dynamics of the esophageal microbiome: a prospective multicenter study

Non-erosive reflux disease (NERD) pathogenesis has not been thoroughly evaluated. Here, we assessed the response of patients with NERD to proton pump inhibitor (PPI) therapy; changes in the microbiome and biologic marker expression in the esophageal mucosa were also evaluated. Patients with NERD (n = 55) received esomeprazole (20 mg) for eight weeks. The treatment response was evaluated at baseline, week four, and week eight. Esophageal mucosal markers and oropharyngeal and esophageal microbiomes were analyzed in patients who underwent upper gastrointestinal endoscopy at screening (n = 18). Complete and partial response rates at week eight were 60.0% and 32.7% for heartburn, and 61.8% and 29.1% for regurgitation, respectively. The expressions of several inflammatory cytokines, including IL-6, IL-8, and NF-κB, were decreased at week eight. Streptococcus, Haemophilus, Prevotella, Veillonella, Neisseria, and Granulicatella were prevalent regardless of the time-point (baseline vs. week eight) and organ (oropharynx vs. esophagus). The overall composition of oropharyngeal and esophageal microbiomes showed significant difference (P = 0.004), which disappeared after PPI therapy. In conclusion, half-dose PPI therapy for eight weeks could effectively control NERD symptoms. The expression of several inflammatory cytokines was reduced in the esophagus, and oropharyngeal and esophageal microbiomes in patients with NERD showed significant difference. However, the microbial compositions in the oropharynx and esophagus were not affected by PPI therapy in this study. Impact of PPI on the microbiome in patients with NERD should be more investigated in future studies.

Exploring Esophageal Microbiomes in Esophageal Diseases: A Systematic Review

Studies that investigated esophageal microbiomes are limited when compared to those on intestinal microbiomes. Nevertheless, several studies have investigated the relationship between esophageal microbiomes and various esophageal diseases, owing to the advancement of next-generation sequencing techniques. Streptococcus is the most common bacterial taxon in a normal esophagus. Additionally, Haemophilus, Neisseria, Prevotella, and Veillonella are also found. However, gram-negative bacteria, including Prevotella, are more abundant in a diseased esophagus, such as in gastroesophageal reflux disease and Barrett’ esophagus. This systematic review aims to summarize current evidences on esophageal microbiomes in various esophageal diseases.

Preoperative Neutrophil Lymphocyte Ratio Can Be Used as a Predictor of Prognosis in Patients With Adenocarcinoma of the Esophagogastric Junction: A Systematic Review and Meta Analysis

Objective: Neutrophil lymphocyte ratio (NLR), Lymphocyte mononuclear cell ratio (LMR), and Platelet lymphocyte ratio (PLR) can be used as various prognostic factors for malignant tumors, but the value of prognosis for patients with adenocarcinoma of the esophagogastric junction (AEG) has not been determined. This study used meta-analysis to assess the value of these indicators in the evaluation of AEG prognosis. Methods: Relevant literatures on the prognostic relationship between NLR, LMR, PLR, and AEG was retrieved from PubMed, Web of Science, Embase, Cochrane Library, Cochrane Central Register of Controlled Trials, Wanfang data, and Chinese National Knowledge Infrastructure. The search time from database establishment to June 30, 2019. The language is limited to English and Chinese. Data was analyzed using Stata 15.0 software. Result: Six retrospective studies were included, five of them involved NLR and six of them involved PLR. No LMR literature that adequately satisfied the conditions was retrieved. Increased NLR was significantly associated with a significant reduction in overall survival (OS), cancer-specific survival (CSS), or disease specific survival (DSS) in patients with AEG [hazard ratio (HR) = 1.545, 95% CI: 1.096-2.179, P < 0.05]. Subgroup analysis showed that NLR had significant value in the prognosis of both Chinese and Non-Chinese patients (P = 0.009 vs. P = 0.000). NLR had significant prognostic value for ≥3 and <3 groups (P = 0.022 vs. P = 0.000). NLR has a significant prognostic value for samples ≥500 and <500 (P = 0.000 vs. P = 0.022). NLR and OS/CSS/DSS single factor meta-regression showed that regional NLR cut-off values and sample size may be the source of heterogeneity in AEG patients (all P < 0.05). There was no significant association between elevated PLR and OS in patients with AEG (HR = 1.117, 95% CI: 0.960-1.300, P > 0.05). PLR had no significant prognostic value for both Chinese and UK patients (P = 0.282 vs. P = 0.429). PLR had no significant prognostic value for ≥150 group and <150 group (P = 0.141 and P = 0.724). No significant prognostic value was found in either the 300 group and <300 group (P = 0.282 vs. P = 0.429). Conclusion: Preoperative NLR rise was an adverse prognostic indicator of AEG. High-risk patients should be treated promptly. The results showed that PLR was not recommended as a prognostic indicator of AEG.

The potential role of P.gingivalis in gastrointestinal cancer: a mini review

Bacterial infection may be involved in the entire process of tissue carcinogenesis by directly or indirectly affecting the occurrence and development of tumors. Porphyromonas gingivalis (P.gingivalis) is an important pathogen causing periodontitis. Periodontitis may promote the occurrence of various tumors. Gastrointestinal tumors are common malignant tumors with high morbidity, high mortality, and low early diagnosis rate. With the rapid development of molecularbiotechnology, the role of P.gingivalis in digestive tract tumors has been increasingly explored. This article reviews the correlation between P.gingivalis and gastrointestinal cancer and the pathogenesis of the latter. The relationship among P.gingivalis, periodontal disease, and digestive tract tumors must be clarifiedthrough a multi-center, prospective, large-scale study.

Evaluation of cancer risk in patients with periodontal diseases

Background/aim

In this study, we aimed to assess the cancer risk among patients with periodontal disease.

Materials and methods

Patients diagnosed with periodontal diseases at Hacettepe University between 2007 and 2012 were included and data on the diagnosis of any cancer after periodontal disease were collected from patient files. The age- and sex-standardized incidence rates (SIRs) were calculated using Turkish National Cancer Registry 2013 data.

Results

A total of 5199 patients were included. Median follow-up was 7.2 years. Patients with periodontal diseases had 17% increased risk of cancer compared with the expected counts for the corresponding age and sex groups (SIR: 1.17; 95% CI: 1.04–1.3, P = 0.006). The increased cancer risk was statistically significant in women (SIR: 1.24; 95% CI: 1.05–1.45, P = 0.008) but not in men. Among women with periodontal disease, the risks of breast cancer (SIR: 2.19) and head and neck cancer (SIR: 4.71) were significantly increased. Among men, the risks of prostate cancer (SIR: 1.84), head and neck cancer (SIR: 3.55), and hematological cancers (SIR: 1.76) were significantly increased.

Conclusion

This study showed that periodontal diseases were associated with increased risk of several cancers. Besides other well-known benefits for health, the provision of oral/dental health should be considered and employed as a cancer prevention measure.

Analysis of Fusobacterium nucleatum and Streptococcus gallolyticus in saliva of colorectal cancer patients

Aim: The aim of the study was to examine the prevalence and amount of Fusobacterium nucleatum (Fn), Porphyromonas gingivalis (Pg) and Streptococcus gallolyticus (Sg) in the saliva of colorectal cancer (CRC) patients and controls. Methods: PCR analyses performed in 71 CRC patients and 77 controls. Results: Saliva samples of patients had higher amounts of Fn (p = 0.001) and Sg (p < 0.001) compared with controls. Amount of Fn and Sg were lower in the microsatellite instability (+) group. Evaluation of salivary Sg amount by receiver operating characteristics analysis found to have diagnostic value for CRC (AUC: 0.84, 95% CI: 0.72-0.96). Conclusion: We found higher amounts of Fn and Sg in the saliva of CRC patients. Salivary Sg could helpful in distinction of CRC.

Oral Health and Cancer

Purpose of review

Recently published studies have provided new evidence for a role of oral health on risk of cancer. This review summarizes the latest research on this topic, including several new cohort studies that have examined associations on periodontal disease and cancer risk.

Recent findings

The most consistent findings for associations with periodontal disease have been observed for lung cancer; five out of seven studies have reported statistically significant increases in risk of lung cancer. For pancreatic, colorectal and head and neck cancers, the associations are less consistent across studies, and the overall summary relative risk estimates are not statistically significant. However, these associations remain of interest, given the limitations of existing data (i.e., measurement error in periodontal disease assessment and small sample sizes), and growing support for biological mechanisms on how bacteria previously linked to periodontal disease may play a role in carcinogenesis.

Summary

Future studies need improved assessment of periodontal disease in population- based studies to determine if heterogeneity of current studies resides with measurement error. Periodontal disease treatment and prevention may turn out to be important targetable cancer prevention strategies.