Differences In Oral Microbiome Research Articles

Microbiome, socioeconomic status (SES), fiber intake, and response to checkpoint inhibitor therapy in patients with non-small cell lung cancer (NSCLC): A pilot study.

e14710 Background: Lung cancer affects a disproportional number of socioeconomically disadvantaged patients (pts). Responses to checkpoint inhibitor therapy (CIT) vary. Microbiome diversity may correlate with benefit from CIT. High fiber diets lead to microbiome diversity. We hypothesize that unexplained lung cancer disparities may be in part due to differences in microbiome diversity determined by unhealthy dietary patterns dictated by lower SES. Methods: Following IRB review, 25 pts with metastatic NSCLC starting CIT-based treatment were enrolled. Pre-treatment oral and fecal samples were collected. 24-hour dietary recalls were obtained. SES index was calculated based on education, employment, housing and annual income. High fiber intake was defined as > 20 g/day. Best treatment response per RECIST 1.1 was assessed. Microbial 16s rRNA were sequenced with Illumina MiSeq platform. Sequence analyses utilized QIIME 2 with DADA2 plugin. Taxonomic assignments used the Greengenes database. Microbiome composition was analyzed by calculating alpha diversity (Chao1, Shannon diversity and Simpson index), beta diversity and differential abundance of microbial compositions. Hierarchical linear model was constructed for each SES variable with and without biological covariates. Results: Pts with samples >1000 operational taxonomic unit (OTU) levels were included (N = 22) in the analysis. 50% were male, median age was 71, 36% (8/22) were of Black race and 23% (5/22) were of low SES. Median fiber intake was 11.9 grams. Males had higher alpha diversity than females (p=.038). Pts with high fiber intake had greater fecal Proteobacteria compared to low fiber intake pts (p<0.05). Bacteroides and Firmicutes fecal levels were significantly different for all pts compared to Human Microbiome Project (HMP) reported normal levels (p<0.01). Actinobacteria and Proteobacteria levels for low-fiber intake pts were also significantly elevated compared to HMP normal levels (p<0.05). There were no differences observed in microbiome when comparing SES index. However, high SES index patients had elevated fecal levels of Actinobacteria, Firmicutes and Proteobacteria and lower levels of Bacteroides compared to HMP levels. There was a trend towards higher alpha diversity of oral samples in partial responders pts compared to those with stable or progression of the disease (p=0.08). Conclusions: Pts with metastatic NSCLC exhibited different microbial composition compared to HMP normal levels. Associations between SES and microbial distribution in such pts warrant further investigation. Increased sample size is needed to better determine differences in oral microbiome in responders to immunotherapy and better evaluate the role of sex in this setting.

Altered composition of the oral microbiome in integrin beta 6-deficient mouse

ABSTRACT In periodontal disease (PD), bacterial biofilms suppress β6 integrin expression transforming growth factor-β1 signaling, resulting in gingival inflammation and bone loss. β6 integrin-null (Itgb6−/− ) mice develop spontaneous PD. The aim of this study was to unravel potential differences in oral microbiome in wild-type (WT) and Itgb6−/− FVB mice. Mouse oral microbiome was analyzed from 3- and 6-month-old WT and Itgb6−/− . The periodontal inflammation and spontaneous bone loss were present in 3-month-old and advanced in 6-month-old Itgb6−/− mice. The observed amplicon sequence variants (ASVs) of alpha diversity showed close similarity in 3-month-old and 6-month-old Itgb6−/− mice. Chao1 and ACE methods revealed that the microbiome in Itgb6−/− mice showed less diversity compared to the WT. UniFrac Principal Coordinate analyses (PCoA) showed a clear spatial segregation and clustering between Itgb6−/− and WT mice in general, and between 3-month- and 6-month-old WT mice. Weighted PCoA showed the tight clustering and distinct separation of individual mouse samples within Itgb6−/− and WT. The most abundant microbial classes varied between the sample groups. However, the genus Aggregatibacter significantly increased in the 6-month-old Itgb6−/− mice. β6 integrin-deficient mice develop periodontal inflammation that may relate to dysbiosis in the microbiome that further promotes the disease process.

Variations in oral microbiome profiles in rheumatoid arthritis and osteoarthritis with potential biomarkers for arthritis screening

The key to arthritis management is early diagnosis and treatment to prevent further joint destruction and maximize functional ability. Osteoarthritis (OA) and rheumatoid arthritis (RA) are two common types of arthritis that the primary care provider must differentiate, in terms of diagnosis and treatment. Effective and non-invasive strategies for early detection and disease identification are sorely needed. Growing evidence suggests that RA has a correlation with oral microbiome and may be affected by its dynamic variations. There is already a study comparing oral microbiome in patients with RA and OA, however, it did not screen for potential biomarkers for arthritis. In this study, we assessed the oral microbiome in saliva samples from 110 RA patients, 67 OA patients and 155 healthy subjects, using 16S rRNA gene amplicon sequencing. The structure and differences in oral microbiome between RA, OA and healthy subjects were analyzed. Eight oral bacterial biomarkers were identified to differentiate RA from OA. This report provides proof of oral microbiota as an informative source for discovering non-invasive biomarkers for arthritis screening.