A distinctive subgingival microbiome in patients with periodontitis and Alzheimer's disease compared with cognitively unimpaired periodontitis patients

Oral Microbiota and Porphyromonas gingivalis Kgp Genotypes Altered in Parkinson's Disease with Mild Cognitive Impairment

Cognitive impairment (CI) is a common complication of the non-motor symptoms in Parkinson's disease (PD), including PD with mild cognitive impairment (PD-MCI) and PD dementia. Recent studies reported the oral dysbiosis in PD and CI, respectively. Porphyromonas gingivalis (P. gingivalis), a pathogen of oral dysbiosis, plays an important role in PD, whose lysine-gingipain (Kgp) could lead to AD-type pathologies. No previous study investigated the composition of oral microbiota and role of P. gingivalis in PD-MCI. This study aimed to investigate the differences of oral microbiota composition, P. gingivalis copy number, and Kgp genotypes among PD-MCI, PD with normal cognition (PD-NC) and periodontal status-matched control (PC) groups. The oral bacteria composition, the copy number of P. gingivalis, and the Kgp genotypes in gingival crevicular fluid from PD-MCI, PD-NC, and PC were analyzed using 16S ribosomal RNA sequencing, quantitative real-time PCR, and MseI restriction. We found that the structures of oral microbiota in PD-MCI group were significantly different compared to that in PD-NC and PC group. The relative abundances of Prevotella, Lactobacillus, Megasphaera, Atopobium, and Howardella were negatively correlated with cognitive score. Moreover, there was a significant difference of Kgp genotypes among the three groups. The predominant Kgp genotypes of P. gingivalis in the PD-MCI group were primarily Kgp II, whereas in the PD-NC group, it was mainly Kgp I. The Kgp II correlated with lower MMSE and MoCA scores, which suggested that Kgp genotypes II is related to cognitive impairment in PD.

Association of Oral Microbiome Diversity and All-Cause Mortality in the General US Population and in Individuals With Chronic Diseases: A Prospective Cohort Study

AIM

To investigate whether oral microbiome diversity is associated with all-cause mortality in the general US population and in individuals with chronic diseases.

MATERIALS AND METHODS

We included 8224 individuals with oral microbiome diversity data from the National Health and Nutrition Examination Survey (2009-2012), representing 164,000,205 US adults, using a survey-weighted analysis method. Cox regression analyses were performed to identify the association between oral microbiome diversity and all-cause mortality.

RESULTS

During a survey-weighted mean follow-up period of 8.86 years, 429 all-cause deaths (survey-weighted number: 7,124,920) occurred in 8224 participants. Cox regression analysis revealed that higher oral microbiome diversity was significantly associated with a lower all-cause mortality risk. Significant differences in all-cause mortality risk were observed among the different clusters based on oral microbiome β-diversity (log-rank p < 0.001). Subgroup analyses revealed that the oral microbiome diversity was independently associated with all-cause mortality in individuals with diabetes mellitus and hypertension. A multivariate logistic regression model showed that current smoking and antibiotic use were significantly associated with lower oral microbiome α diversity.

CONCLUSIONS

Higher oral microbiome diversity was significantly associated with a lower all-cause mortality risk in the general US population and in individuals with diabetes mellitus and hypertension.

Research Trends in the Comorbidity Between Periodontitis and Neurodegenerative Diseases

INTRODUCTION AND AIMS

Evidence suggests an association between periodontitis and neurodegenerative diseases, but a comprehensive analysis of research trends remains absent. Therefore, we aim to identify research trends and hotspots on the comorbidity between periodontitis and neurodegenerative diseases, understand mechanisms, provide guidance for subsequent studies and show its clinical translational possibility.

METHODS

A bibliometric analysis covering 1982 to 2023 was conducted using the Web of Science Core Collection. English-language articles range from January 1, 1982 to November 30, 2023 were analyzed. Data were downloaded on November 30, 2023 and analyzed on December, 2023. Data visualization and statistical analysis were performed to identify trends of annual publications, countries, sources, institutions, authors, most cited articles, and keywords by using Microsoft Excel, VOSviewer, Citespace, R-bibliometrix and Origin Pro.

RESULTS

A total of 1,238 articles from 1982 to 2023 on the comorbidity between periodontitis and neurodegenerative diseases were identified. Annual publications showed an upward trend. The United States, University College of London, BRAIN and Shy, Michael E. were the leading nation, affiliation, source and author, respectively. The United States, NEUROLOGY, and Curtis Maurice A. were the most cited nation, source, and author. Keywords network analysis highlighted 'Charcot-Marie-Tooth Disease', 'Alzheimer's Disease' and 'Periodontitis' as focal points. Detection of keywords citation bursts demonstrated 'Porphyromonas gingivalis' and 'Cognitive Dysfunction' as hot topics in recent research.

CONCLUSIONS

In recent years, emerging interests of the comorbidity between periodontitis and neurodegenerative diseases (NDs) are growing. Our study enhances the understanding of recent research trends of periodontitis and NDs and provides valuable perspectives within this expanding field, offering new insights into research trends regarding the interplay between 'Porphyromonas gingivalis' and 'Cognitive Dysfunction'. Further research of the molecular mechanisms between P. gingivalis-induced periodontitis, neuroinflammation, that leads neurodegeneration are clearly warranted.

Frequency of Fimbrial Gene Types I, Ib, and II in Clinical Strains of Porphyromonas gingivalis Characterized From Periodontitis Patients

Objective Porphyromonas gingivalis (P. gingivalis) is considered the predominant pathogen in association with different stages of periodontitis, and fim genes play a vital role in adherence and colonization. This study is thus aimed to detect the prevalence of P. gingivalis and the frequency of fim gene types among the clinical strains isolated from periodontitis patients. Methods Plaque samples (N = 45) were collected from patients with three different stages of periodontitis (n = 15 in each group). All the samples were inoculated onto sterile anaerobic blood agar and were processed anaerobically using a GasPak system at 37°C for five to seven days. Standard microbiological techniques were used to identify P. gingivalis. Genomic DNA was extracted, and polymerase chain reaction (PCR) was carried out to detect the frequency of three fim gene types, using specific primers. Results P. gingivalis was more prevalent in Group III (93.3%), followed by 26.7% in Group II, and 13.3% in Group I. Maximum isolates were seen in the age group of 40-50, with no significance within the genders. fim type I was frequent in Group III (78.5% (n = 11)), followed by 0.25% (n = 1) under Group II, with no other fim types in the other groups.  Conclusion Prevalence of P. gingivalis and frequency of fim genes, in association with its virulence, were observed. Periodical monitoring of such virulence genes would aid in the theranostic approach to combat the complications caused by P. gingivalis in periodontitis cases.

Ecological competition in the oral mycobiome of Hispanic adults living in Puerto Rico associates with periodontitis

Background: Fungi are a major component of the human microbiome that only recently received attention. The imbalance of indigenous fungal communities and environmental fungi present in the oral cavity may have a role in oral dysbiosis, which could exacerbate oral inflammatory diseases. Methods: We performed a cross-sectional study and recruited 88 participants aged 21 to 49 from sexually transmitted infection clinics in Puerto Rico. A full-mouth periodontal examination following the NHANES protocol defined periodontal severity (CDC/AAP). ITS2 (fungal) genes were amplified and sequenced for mycobiota characterization of yeast and environmental fungi. Environmental outdoor spore levels were measured daily by the American Academy of Allergy Asthma and Immunology San Juan station and defined by quartiles as spore scores. Results: Our data indicate polymicrobial colonization of yeast and environmental fungi in the oral cavity. Dominant taxa associated with periodontal disease included Saccharomyces cerevisiae, Rigidoporus vinctus, and Aspergillus penicilloides, while Candida albicans were found to be ubiquitous. Fungal aerosols were found to impact the oral cavity biofilm, likely due to competition and neutralization by inhaled outdoor and indoor fungal spores. Conclusion: To our knowledge, this is the first report showcasing the ecological competition of measured outdoor environmental fungi with the human oral mycobiota.