-
Journal of Alzheimer's Disease Reports 2021Alzheimer's disease (AD) is a chronic neurodegenerative disease that accounts for more than 50% of all dementia cases worldwide. There is wide consensus on the risk...
BACKGROUND
Alzheimer's disease (AD) is a chronic neurodegenerative disease that accounts for more than 50% of all dementia cases worldwide. There is wide consensus on the risk factors of AD; however, a clear etiology remains unknown. Evidence suggests that the inflammatory-mediated disease model, such as that found with periodontal disease due to (), plays a role in AD progression.
OBJECTIVE
This study aims to systematically review the literature on the association between to AD, and to identify the homogeneity of the methods used across studies to measure involvement in AD.
METHODS
We systematically searched studies on Cochrane library, Ovid Medline, PubMed, Web of Science, WHOLIS, Google Scholar databases, and reference lists of identified studies.
RESULTS
6 studies out of 636 identified records fulfilled all eligibility criteria. Results showed no clear pathophysiology of AD due to and its various virulence factors. No consensus was found in the literature pertaining to the method of measurement of AD or and its virulence factors.
CONCLUSION
The included studies suggest that bacteria play a role in the process of systemic inflammation which leads to cerebrospinal fluid inflammation and indirectly cause hastening of AD onset and progression. Our included studies revealed heterogeneity in the methodologies of measurement of AD and/or and its virulence factors, which opens discussion about the benefits and weakness of possible standardization.
PubMed: 34755046
DOI: 10.3233/ADR-200237 -
Frontiers in Cellular and Infection... 2021The development of periodontitis is associated with an imbalanced subgingival microbial community enriched with species such as the traditionally classified red-complex... (Meta-Analysis)
Meta-Analysis
The development of periodontitis is associated with an imbalanced subgingival microbial community enriched with species such as the traditionally classified red-complex bacteria (, , and ). Saliva has been suggested as an alternative to subgingival plaque for the microbial analysis due to its easy and non-invasive collection. This systematic review aims to determine whether the levels of red-complex bacteria assessed using saliva reflect those in subgingival plaque from periodontitis patients. The MEDLINE, EMBASE, and Cochrane Library databases were searched up to April 30, 2021. Studies were considered eligible if microbial data of at least one of the red-complex species were reported in both saliva and subgingival plaque from periodontitis patients, based on DNA-based methods. Of the 17 included studies, 4 studies used 16S rRNA gene sequencing techniques, and the rest used PCR-based approaches. The detection frequency of each red-complex species in periodontitis patients was reported to be > 60% in most studies, irrespective of samples types. Meta-analyses revealed that both detection frequencies and relative abundances of red-complex bacteria in saliva were significantly lower than those in subgingival plaque. Moreover, the relative abundances of all 3 bacterial species in saliva showed significantly positive correlation with those in subgingival plaque. In conclusion, current evidence suggests that one-time saliva sampling cannot replace subgingival plaque for microbial analysis of the red-complex bacteria in periodontitis patients. Given the positive microbial associations between saliva and subgingival plaque, a thorough review of longitudinal clinical studies is needed to further assess the role of saliva.
Topics: Aggregatibacter actinomycetemcomitans; Humans; Periodontitis; Porphyromonas gingivalis; RNA, Ribosomal, 16S; Saliva; Treponema denticola
PubMed: 34692561
DOI: 10.3389/fcimb.2021.727732 -
International Journal of Environmental... Sep 2021The hypothesis of an infectious connection from the oro-pharyngeal sphere to the brain underlines the interest in analyzing the link between periodontal disease and... (Review)
Review
The hypothesis of an infectious connection from the oro-pharyngeal sphere to the brain underlines the interest in analyzing the link between periodontal disease and Alzheimer's disease. The aim of this systematic review was to examine the link between Alzheimer's disease and periodontal disease in patients aged 65 and over. Databases (PubMed (MEDLINE), the Cochrane Library, and Embase) were analyzed for relevant references up to 21 June 2021. The authors independently selected the studies and extracted the data. The quality of included studies was checked using the National Institutes of Health's quality assessment tools. Five studies were included. The selected studies described in their results an increase in in Alzheimer's disease patients (adjusted = 0.02), and its incidence was linked to and (adjusted HR = 1.22 (1.04-1.43), = 0.012) as well as (crude HR = 2.0 (1.1-3.8)). The presence of periodontitis at baseline was associated with a six-fold increase in the rate of cognitive decline over a 6-month follow-up period (ADAS-Cog mean change = 2.9 ± 6.6). The current review suggests an association between periodontal disease and Alzheimer's disease. The treatment of periodontal disease could be a way to explore Alzheimer's disease prevention.
Topics: Alzheimer Disease; Brain; Cognitive Dysfunction; Humans; Periodontal Diseases; Periodontitis
PubMed: 34501899
DOI: 10.3390/ijerph18179312 -
Frontiers in Pharmacology 2021At the initial part of the gastrointestinal tract, multiple tissues serve the normal function of food delivery. Periodontal structures are integral elements of these.... (Review)
Review
At the initial part of the gastrointestinal tract, multiple tissues serve the normal function of food delivery. Periodontal structures are integral elements of these. When they deteriorate, it is extremely challenging to regenerate and reconstruct them. The conventional intervention for periodontal disease is scaling and root planning with the aim of reducing pathogenic bacteria. However, periodontal pathogens can rapidly recolonize treated areas. Probiotics have been proposed as novel tools for managing oral health by suppressing pathogenic bacteria through their anti-inflammatory effect, but the available data are controversial. Therefore, we performed a meta-analysis to study the effect of probiotics on periodontal pathogenic bacteria. The study was registered in PROSPERO under registration number CRD42018094903. A comprehensive literature search from four electronic databases (PubMed, Cochrane CENTRAL, Embase, and Web of Science) yielded nine eligible records for statistical analysis. Studies measuring bacterial counts in saliva and supra- and subgingival plaque were included. Bacterial counts were analyzed using standard mean difference (SMD) and by a random effects model with the DerSimonian-Laird estimation. The results showed a significant decrease in the overall count of in the probiotic-treated group compared to the control at 4 weeks (SMD: -0.28; 95% CI: -0.56--0.01; = 0.045) but not later. Analyzing the bacterial counts in subgroups, namely, in saliva and supra- and subgingival plaque, separately, yielded no significant difference. Probiotics had no significant effect on the overall count of at 4 weeks (SMD: -0.02; 95% CI: -0.35-0.31; = 0.914) or later. Subgroup analysis also revealed no significant difference between treatment and control groups nor did probiotics significantly decrease the overall and subgroup bacterial counts of , , and . Our data support the beneficial effect of probiotics in reducing counts, but not of other key periodontal pathogenic bacteria in periodontal disease patients. However, due to the complex mechanism associated with periodontal disease and the limitations of the available studies, there is a further need for well-designed randomized clinical trials to assess the efficacy of probiotics.
PubMed: 34447307
DOI: 10.3389/fphar.2021.682656 -
Scientific Reports Aug 2021Understanding changes in oral flora during pregnancy, its association to maternal health, and its implications to birth outcomes is essential. We searched PubMed,... (Meta-Analysis)
Meta-Analysis
Understanding changes in oral flora during pregnancy, its association to maternal health, and its implications to birth outcomes is essential. We searched PubMed, Embase, Web of Science, and Cochrane Library in May 2020 (updated search in April and June 2021), and conducted a systematic review and meta-analyses to assess the followings: (1) oral microflora changes throughout pregnancy, (2) association between oral microorganisms during pregnancy and maternal oral/systemic conditions, and (3) implications of oral microorganisms during pregnancy on birth outcomes. From 3983 records, 78 studies were included for qualitative assessment, and 13 studies were included in meta-analysis. The oral microflora remains relatively stable during pregnancy; however, pregnancy was associated with distinct composition/abundance of oral microorganisms when compared to postpartum/non-pregnant status. Oral microflora during pregnancy appears to be influenced by oral and systemic conditions (e.g. gestational diabetes mellitus, pre-eclampsia, etc.). Prenatal dental care reduced the carriage of oral pathogens (e.g. Streptococcus mutans). The Porphyromonas gingivalis in subgingival plaque was more abundant in women with preterm birth. Given the results from meta-analyses were inconclusive since limited studies reported outcomes on the same measuring scale, more future studies are needed to elucidate the association between pregnancy oral microbiota and maternal oral/systemic health and birth outcomes.
Topics: Female; Humans; Microbiota; Mouth; Periodontal Diseases; Pregnancy; Pregnancy Outcome; Premature Birth; Publication Bias; Risk
PubMed: 34413437
DOI: 10.1038/s41598-021-96495-1 -
Cancer Epidemiology, Biomarkers &... Oct 2020The microbiome has been hypothesized to play a role in cancer development. Because of the diversity of published data, an overview of available epidemiologic evidence...
The microbiome has been hypothesized to play a role in cancer development. Because of the diversity of published data, an overview of available epidemiologic evidence linking the microbiome with cancer is now needed. We conducted a systematic review using a tailored search strategy in Medline and EMBASE databases to identify and summarize the current epidemiologic literature on the relationship between the microbiome and different cancer outcomes published until December 2019. We identified 124 eligible articles. The large diversity of parameters used to describe microbial composition made it impossible to harmonize the different studies in a way that would allow meta-analysis, therefore only a qualitative description of results could be performed. Fifty studies reported differences in the gut microbiome between patients with colorectal cancer and various control groups. The most consistent findings were for , and being significantly enriched in fecal and mucosal samples from patients with colorectal cancer. For the oral microbiome, significantly increased and decreased abundance was reported for and , respectively, in patients with oral cancer compared with controls. Overall, although there was a large amount of evidence for some of these alterations, most require validation in high-quality, preferably prospective, epidemiologic studies.
Topics: Gastrointestinal Microbiome; Humans; Neoplasms; Risk
PubMed: 32727720
DOI: 10.1158/1055-9965.EPI-20-0288 -
Experimental Dermatology Oct 2021Hidradenitis suppurativa (HS), also known as acne inversa, is a chronic inflammatory skin disease with still largely unknown pathogenesis. While infectious organisms...
Hidradenitis suppurativa (HS), also known as acne inversa, is a chronic inflammatory skin disease with still largely unknown pathogenesis. While infectious organisms have been identified in lesions of the disease since the 1980s, questions remain over the role that bacteria and microbiome play. Recent studies using 16S ribosomal RNA gene sequencing and larger culture-based studies have begun to paint a clearer picture of the microbial world of HS. With this systematic review, we summarize all the work that has been done to date in HS bacteriology, analyse potential pitfalls and limitations of the current studies, and address future directions of investigation. This systematic review attempted to collate and analyse all bacteriology studies done to date. This review was prospectively registered with PROSPERO (1670769) performed in line with the PRISMA checklist. Twenty two studies were identified comprising 862 individual HS patients for culture studies and 206 HS patients for 16S rRNA gene sequencing studies. Methodology tended to be varied, with different sampling, culturing and sequencing methods as well as amount of analysis and stratification of patients. Bacteria identified as elevated in HS lesions in sequencing studies as well as grown from HS lesions in culture studies are identified and discussed. These primarily included the anerobic Gram-negative bacilli Prevotella, Porphyromonas and Fusibacterium, the Gram-positive bacilli Corynebacterium, and the Gram-positive cocci Staphylococcus, Streptococcus and Parvimonas. Potential interactions, as well as work in other disease models with related bacteria are also discussed. Areas of further investigation include in vitro studies of interactions between bacteria and keratinocytes, gut and oral microbiome studies and deep sequencing studies for virulence and phage factors.
Topics: Hidradenitis Suppurativa; Humans; Metagenomics; Microbiota; Skin
PubMed: 32614993
DOI: 10.1111/exd.14141 -
Oral Diseases Jul 2021This systematic review was to evaluate the change of oral microbiome based on next-generation sequencing (NGS)-metagenomic analysis following periodontal interventions... (Review)
Review
OBJECTIVES
This systematic review was to evaluate the change of oral microbiome based on next-generation sequencing (NGS)-metagenomic analysis following periodontal interventions among systematically healthy subjects.
MATERIALS AND METHODS
A structured search strategy consisting of "metagenomics" and "oral diseases" was applied to PubMed, EMBASE, and Web of Science to identify effective papers. The included studies were original studies published in English, using metagenomic approach to analyze the effectiveness of periodontal intervention on oral microbiome among systematically healthy human subjects with periodontitis.
RESULTS
A total of 12 papers were included in this review. Due to the heterogeneity of selected study, quantitative analysis was not performed. The findings as to how alpha diversity changed after interventions were not consistent across studies. Six studies illustrated clear separation of microbial composition between dental plaque samples collected before and after intervention using principal coordinates/component analysis. The most commonly detected genera before intervention were Porphyromonas, Treponema, Tannerella, and Prevotella, while Streptococcus and Actinomyces usually increased and became the dominant genera after intervention. Correlation network analysis revealed that after intervention, the topology of network was different compared to the corresponding pre-interventional samples.
CONCLUSION
Existing evidence of metagenomic studies depicts a complex change in oral microbiome after periodontal intervention.
Topics: High-Throughput Nucleotide Sequencing; Humans; Metagenome; Metagenomics; Microbiota; Periodontitis
PubMed: 32390250
DOI: 10.1111/odi.13405 -
Microorganisms May 2020This review aimed to systematically compare microbial profiles of peri-implantitis to those of periodontitis and healthy implants. Therefore, an electronic search in... (Review)
Review
This review aimed to systematically compare microbial profiles of peri-implantitis to those of periodontitis and healthy implants. Therefore, an electronic search in five databases was conducted. For inclusion, studies assessing the microbiome of peri-implantitis in otherwise healthy patients were considered. Literature was assessed for consistent evidence of exclusive or predominant peri-implantitis microbiota. Of 158 potentially eligible articles, data of 64 studies on 3730 samples from peri-implant sites were included in this study. Different assessment methods were described in the studies, namely bacterial culture, PCR-based assessment, hybridization techniques, pyrosequencing, and transcriptomic analyses. After analysis of 13 selected culture-dependent studies, no microbial species were found to be specific for peri-implantitis. After assessment of 28 studies using PCR-based methods and a meta-analysis on 19 studies, a higher prevalence of and (log-odds ratio 4.04 and 2.28, respectively) was detected in peri-implantitis biofilms compared with healthy implants. spp., spp. and spp. were found in all five pyrosequencing studies in healthy-, periodontitis-, and peri-implantitis samples. In conclusion, the body of evidence does not show a consistent specific profile. Future studies should focus on the assessment of sites with different diagnosis for the same patient, and investigate the complex host-biofilm interaction.
PubMed: 32369987
DOI: 10.3390/microorganisms8050661 -
Medicine Apr 2020Periodontal bacteria is the major pathogens in the oral cavity and the main cause of adult chronic periodontitis, but their association with incidence and prognosis in... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Periodontal bacteria is the major pathogens in the oral cavity and the main cause of adult chronic periodontitis, but their association with incidence and prognosis in cancer is controversial. The aim of this study was to evaluate the effect of periodontal bacteria infection on incidence and prognosis of cancer.
METHODS
A systematic literature search of PubMed, Embase, Web of Science, and Cochrane Library databases was performed to obtain 39 studies comprising 7184 participants. The incidence of cancer was evaluated as odd ratios (OR) with a 95% confidence interval (95% CI) using Review Manager 5.2 software. Overall survival, cancer-specific survival and disease-free survival, which were measured as hazard ratios (HR) with a 95% CI using Review Manager 5.2 software.
RESULTS
Our results indicated that periodontal bacteria infection increased the incidence of cancer (OR = 1.25; 95%CI: 1.03-1.52) and was associated with poor overall survival (HR = 1.75; 95% CI: 1.40-2.20), disease-free survival (HR = 2.18; 95%CI: 1.24-3.84) and cancer-specific survival (HR = 1.85, 95%CI: 1.44-2.39). Subgroup analysis indicted that the risk of cancer was associated with Porphyromonas gingivalis (Pg) infection (OR = 2.16; 95%CI: 1.34-3.47) and Prevotella intermedia (Pi) infection (OR = 1.28; 95%CI: 1.01-1.63) but not Tannerella forsythia (Tf) (OR = 1.06; 95%CI: 0.8-1.41), Treponema denticola (Td) (OR = 1.30; 95%CI: 0.99-1.72), Aggregatibacter actinomycetemcomitans (Aa) (OR = 1.00; 95%CI: 0.48-2.08) and Fusobacterium nucleatum (Fn) (OR = 0.61; 95%CI: 0.32-1.16).
CONCLUSION
This meta-analysis revealed periodontal bacteria infection increased the incidence of cancer and predicted poor prognosis of cancer.
Topics: Aggregatibacter actinomycetemcomitans; Bacterial Infections; Chronic Periodontitis; Disease-Free Survival; Fusobacterium nucleatum; Humans; Incidence; Mouth; Neoplasms; Porphyromonas gingivalis; Prevotella intermedia; Prognosis; Risk Assessment; Treponema denticola
PubMed: 32282725
DOI: 10.1097/MD.0000000000019698