From Mouth to Brain: Distinct Supragingival Plaque Microbiota Composition in Cerebral Palsy Children With Caries

Oral microbiome dysbiosis may be associated with intra cranial aneurysms

BACKGROUND

Although the etiology of aneurysms remains elusive, recent advances in high-throughput sequencing technology and ongoing human microbiome investigations suggest a potential link between microbiome composition and the onset of various human diseases.

OBJECTIVE

This study aimed to utilize high-throughput 16 S rRNA gene sequencing to analyze the oral flora bacterial profiles of individuals, comparing patients with intracranial aneurysms to a healthy control group. Importantly, we sought to identify differences in the oral microbiota and offer novel insights and methods for early diagnosis and identification of intracranial aneurysms.

METHOD

Saliva samples were collected from 60 patients with cerebral aneurysms (case group) and 130 healthy individuals (control group). The V3-V4 region of the bacterial 16 S rRNA gene was amplified and sequenced using the HiSeq high-throughput sequencing platform to establish the bacterial profile. Sequencing data were analyzed using QIIME2 and Metastats software to compare composition differences and relative abundance at the phylum and genus levels in the oral microbiota of the two groups.

RESULTS

Significant differences in oral microbiota composition were observed between patients in the case and control groups (P < 0.05). Genus-level identification highlighted key positions occupied by Eubacterium, Saccharimonadaceae, Rothia, Gemella, Streptococcus, Lactobacillales, Phocaeicola, Bacteroides, Saccharimonadales, and Abiotrophia.

CONCLUSION

This study revealed noteworthy distinctions in the composition, abundance, and diversity of oral microbiota between intracranial aneurysm patients and healthy controls. These disparities suggest a potential correlation between oral microbiota and the development of intracranial aneurysms, offering new avenues for early diagnosis and intervention. However, limitations such as a small sample size, lack of prospective design, and absence of causal inference warrant further validation and exploration.

Probiotic Lactobacillus fermentum TSF331, Lactobacillus reuteri TSR332, and Lactobacillus plantarum TSP05 improved liver function and uric acid management-A pilot study

Metabolic-associated fatty liver disease (MAFLD) is predominantly associated with metabolic disturbances representing aberrant liver function and increased uric acid (UA) levels. Growing evidences have suggested a close relationship between metabolic disturbances and the gut microbiota. A placebo-controlled, double-blinded, randomized clinical trial was therefore conducted to explore the impacts of daily supplements with various combinations of the probiotics, Lactobacillus fermentum TSF331, Lactobacillus reuteri TSR332, and Lactobacillus plantarum TSP05 with a focus on liver function and serum UA levels. Test subjects with abnormal levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and UA were recruited and randomly allocated into six groups. Eighty-two participants successfully completed the 60-day intervention without any dropouts or occurrence of adverse events. The serum AST, ALT, and UA levels were significantly reduced in all treatment groups (P < 0.05). The fecal microbiota analysis revealed the intervention led to an increase in the population of commensal bacteria and a decrease in pathobiont bacteria, especially Bilophila wadsworthia. The in vitro study indicated the probiotic treatments reduced lipid accumulation and inflammatory factor expressions in HepG2 cells, and also promoted UA excretion in Caco-2 cells. The supplementation of multi-strain probiotics (TSF331, TSR332, and TSP05) together can improve liver function and UA management and may have good potential in treating asymptomatic MAFLD. Trial registration. The trial was registered in the US Library of Medicine (clinicaltrials.gov) with the number NCT06183801 on December 28, 2023.

From teeth to brain: dental caries causally affects the cortical thickness of the banks of the superior temporal sulcus

OBJECTIVES

Dental caries is one of the most prevalent oral diseases and causes of tooth loss. Cross-sectional studies observed epidemiological associations between dental caries and brain degeneration disorders, while it is unknown whether dental caries causally affect the cerebral structures. This study tested whether genetically proxied DMFS (the sum of Decayed, Missing, and Filled tooth Surfaces) causally impacts the brain cortical structure using Mendelian randomization (MR).

METHODS

The summary-level GWAS meta-analysis data from the GLIDE consortium were used for DMFS, including 26,792 participants. ENIGMA (Enhancing NeuroImaging Genetics through Meta Analysis) consortium GWAS summary data of 51,665 patients were used for brain structure. This study estimated the causal effects of DMFS on the surface area (SA) and thickness (TH) of the global cortex and functional cortical regions accessed by magnetic resonance imaging (MRI). Inverse-variance weighted (IVW) was used as the primary estimate, the MR pleiotropy residual sum and outlier (MR-PRESSO), the MR-Egger intercept test, and leave-one-out analyses were used to examine the potential horizontal pleiotropy.

RESULTS

Genetically proxied DMFS decreases the TH of the banks of the superior temporal sulcus (BANSSTS) with or without global weighted (weighted, β = - 0.0277 mm, 95% CI: - 0.0470 mm to - 0.0085 mm, P = 0.0047; unweighted, β = - 0.0311 mm, 95% CI: - 0.0609 mm to - 0.0012 mm, P = 0.0412). The causal associations were robust in various sensitivity analyses.

CONCLUSIONS

Dental caries causally decrease the cerebral cortical thickness of the BANKSSTS, a cerebral cortical region crucial for language-related functions, and is the most affected brain region in Alzheimer's disease. This investigation provides the first evidence that dental caries causally affects brain structure, proving the existence of teeth-brain axes. This study also suggested that clinicians should highlight the causal effects of dental caries on brain disorders during the diagnosis and treatments, the cortical thickness of BANKSSTS is a promising diagnostic measurement for dental caries-related brain degeneration.

Bacterial extracellular vesicles in biofluids as potential diagnostic biomarkers

INTRODUCTION

Extracellular vesicles (EVs) are spherical membrane-derived lipid bilayers released by cells. The human microbiota consists of trillions of microorganisms, with bacteria being the largest group secreting microbial EVs. The discovery of bacterial EVs (BEVs) has garnered interest among researchers as potential diagnostic markers, given that the microbiota is known to be associated with various diseases and EVs carry important macromolecular cargo for intercellular interaction.

AREAS COVERED

The differential bacterial composition identified from BEVs isolated from biofluids between patients and healthy controls may be valuable for detecting diseases. Therefore, BEVs may serve as novel diagnostic markers. Literature search on PubMed and Google Scholar databases was conducted. In this special report, we outline the commonly used approach for investigating BEVs in biofluids, the 16S ribosomal RNA gene sequencing of V3-V4 hypervariable regions, and the recent studies exploring the potential of BEVs as biomarkers for various diseases.

EXPERT OPINION

The emerging field of BEVs offers new possibilities for the diagnosis of various types of diseases, although there remain issues that need to be resolved in this research area to implement BEVs in clinical applications. Hence, it is important for future studies to take these challenges into consideration when investigating the diagnostic value of BEVs.

The impact of Er:YAG laser combined with fluoride treatment on the supragingival plaque microbiome in children with multiple caries: a dynamic study

BACKGROUND

As a minimally invasive tool for caries prevention tool, the pulsed erbium:yttrium-aluminum-garnet (Er:YAG) laser is being used in a large number of studies. Microorganisms are extremely vital in the occurrence and development of dental caries. However, the impact of Er:YAG laser irradiation combined with fluoride on the dynamic microbial changes that occur in dental plaques is still uncertain. In this study, we examined the effect of an Er:YAG laser combined with fluorine on supragingival microbial composition and diversity in children with multiple caries.

METHODS

In this study, dental plaque samples (n = 48) were collected from 12 children with over 8 filled teeth. Supragingival plaques from left mandibular molars before (CB) and after fluoride treatment (CA) and right mandibular molars before (EB) and after fluoride+Er:YAG laser treatment (EA) were collected from each patient. In CB and EB groups, the samples were collected just before the treatments. In CA and EA groups, the samples were collected 1 month after treatments. Then, all specimens were subjected to 16S rRNA high-throughput sequencing to investigate the changes in microbial composition and diversity in mandibular molar supragingival plaques before and after fluoride or fluoride+Er:YAG laser treatment.

RESULTS

The dental plaque microbial diversity was higher in the EA group than in the EB group (baseline levels), and the microbial composition changed in EA group compared with EB group (P < 0.05). The levels of microorganisms associated with caries occurrence, including Proteobacteria, Fusobacteria, and Bacteroidetes, declined, while the levels of Faecacterium, Fastidiosipila, Vibrio, and Shewanella increased in EA group compared with EB group. The declines in Firmicutes, Streptococcus, Fusobacterium, and Veillonella levels were significantly lower in the EA group than in the CA group.

CONCLUSION

The combined application of the Er:YAG laser and fluoride may be more effective than using fluoride alone in reducing the proportion of cariogenic bacteria, increasing the diversity of plaque microorganisms, and further promoting the microecological balance.

Correlations between gastrointestinal and oral microbiota in children with cerebral palsy and epilepsy

We here studied the correlation between gut and oral microbiota in children with cerebral palsy and Epilepsy (CPE). We enrolled 27 children with this condition from the social welfare center of Longgang District, collected their oral plaque and stool samples, and analyzed their gut microbiota (GM) and oral microbiota (OM) through 16S rRNA gene sequencing. Taxonomical annotation revealed that the levels of Firmicutes and Bacteroides in the oral cavity were significantly lower in CPE children than in healthy children, whereas the abundance of Actinomycetes increased significantly in CPE children. In addition, Prevotella, Fusobacterium, and Neisseria were the top three abundant genera, representing 15.49%, 9.34%, and 7.68% of the OM and suggesting potential correlations with caries, periodontitis, and malnutrition. For the GM, Bifidobacterium, Bacteroides, and Prevotella were the top three abundant genera in CPE children and probably contributed to the development of chronic inflammation and malnutrition. Furthermore, the OM and GM correlated with each other closely, and the bacterial components of these microbiota in CPE children were remarkably different from those in healthy children, such as Bifidobacterium, Fusobacterium, Bacteroides, and Neisseria. Conclusively, dysbiotic OM can translocate to the intestinal tract and induce GM dysbiosis, suggesting the consistency between OM and GM variations. Altered oral and gut microbial structures have potential impacts on the occurrence of clinical diseases such as periodontitis, caries, and malnutrition.