Study of the gut microbiome in Egyptian patients with active ulcerative colitis

Gut commensal Alistipes shahii improves experimental colitis in mice with reduced intestinal epithelial damage and cytokine secretion

The commensal bacterium Alistipes shahii is a core microbe of the human gut microbiome and its abundance is negatively correlated with inflammatory bowel diseases (IBDs). However, its fundamental role in regulating inflammatory response remains unknown. Using a dextran sulfate sodium (DSS)-induced colitis mouse model, we examined the effect of A. shahii strain As360 intervention on host inflammatory response and found that A. shahii As360 alleviated disease activity index, colon shortening, and colonic histopathological lesion. The levels of tight junction proteins (mainly ZO1 and claudin-1) were decreased in DSS-induced colitis mice, whereas the levels of these proteins were elevated in colitis mice with A. shahii As360 treatment. In addition, A. shahii As360 treatment led to alterations in cytokine release, especially an increase of IL10. It also led to reduced expressions of mtor and Nlrp3 and increased expression of mTOR inhibitor Ddit4 at the transcriptional level. 16S rRNA amplicon sequencing found that Bacteroides, a producer of short-chain fatty acids (SCFAs), was enriched in the fecal samples of mice with A. shahii treatment. Metabolic analyses found that, following A. shahii As360 treatment, the SCFAs in the fecal content was increased whereas lactic acid was decreased in the cecal content. These findings suggest that supplementation with A. shahii As360 is a promising strategy to prevent colitis.IMPORTANCEAs one of the core microbes and keystone species in the human gut, Alistipes shahii has the potential to inhibit inflammation and improve inflammatory bowel diseases (IBDs) conditions. In this study, we experimentally demonstrated that oral administration of A. shahii As360 alleviated symptoms of colitis, altered the release of cellular inflammatory factors, reduced the intestinal epithelial barrier damage, and changed gut microbiota and fecal metabolites. These findings provide a deeper understanding of the beneficial effects of A. shahii and its perspective for better strategies to prevent IBD.

Correlation between gut microbiota dysbiosis, metabolic syndrome and breast cancer

Breast cancer is a widespread cancer with a high death rate globally. The incidence of breast cancer is expected to increase, particularly in low and middle-income countries due to environmental factors and lifestyle changes. Several risk factors, such as age, family history, hormonal and reproductive factors, have been identified to influence breast cancer development. Metabolic syndrome, is a metabolic disorder that has also been linked to breast cancer risk. The gut microbiome has been suggested as one of the environmental factors leading to breast cancer. The human microbiome is mainly colonized in the intestine by various bacterial species, including Lactobacillus, Bifidobacterium, and Streptococcus and protect the host against pathogenic microorganisms and regulate the immune system. This study included 50 female breast cancer patients and 50 healthy controls with matched ages. Stool fresh samples were taken from test and control groups and stored at - 20 °C until further investigations. DNA of the bacteria in stool samples was extracted using reverse transcription-quantitative polymerase chain reaction to check for the bacterial 16s rRNA gene. The exclusion criteria included other malignancies, recent intestinal surgery, infectious diarrhea, prolonged use of antibiotics, substance addiction, and pregnancy or lactation. Our findings exhibited that breast cancer patients had a higher incidence of metabolic syndrome (60%) compared to cancer-free controls (40%). Furthermore, breast cancer patients had significantly lower Bifidobacterium and Lactobacillus counts than the controls. No significant difference was found in Streptococcus counts between groups. These findings support the relationship between breast cancer and metabolic syndrome and suggest the potential involvement of Lactobacillus and Bifidobacterium in breast cancer pathophysiology. Our study supports the relation between breast cancer and disorder of metabolic syndrome and suggests the potential involvement of Lactobacillus and Bifidobacterium in breast cancer pathophysiology. Further research is necessary to investigate the complex interactions between genes, the environment, and the gut microbiome in breast cancer development. Understanding these interactions could lead to the progress of novel strategies for breast cancer prevention and treatment.

Long-read 16S rRNA amplicon sequencing reveals microbial characteristics in patients with colorectal adenomas and carcinoma lesions in Egypt

BACKGROUND

Colorectal cancer (CRC) is among the five leading causes of cancer incidence and mortality. During the past decade, the role of the gut microbiota and its dysbiosis in colorectal tumorigenesis has been emphasized. Metagenomics and amplicon-based microbiome profiling provided insights into the potential role of microbial dysbiosis in the development of CRC.

AIM

To address the scarcity of information on differential microbiome composition of tumor tissue in comparison to adenomas and the lack of such data from Egyptian patients with CRC.

MATERIALS AND METHODS

Long-read nanopore sequencing of 16S rRNA amplicons was used to profile the colonic microbiota from fresh colonoscopic biopsy samples of Egyptian patients with CRC and patients with colonic polyps.

RESULTS

Species richness of CRC lesions was significantly higher than that in colonic polyps (p-value = 0.0078), while evenness of the CRC group was significantly lower than the colonic polyps group (p-value = 0.0055). Both species richness and Shannon diversity index of the late onset CRC samples were significantly higher than those of the early onset ones. The Firmicutes-to-Bacteroidetes (F/B) ratio was significantly higher in the CRC group than in the colonic polyps group (p-value = 0.0054), and significantly higher in samples from early-onset CRC. The Enterococcus spp. were significantly overabundant in patients with rectal cancer and early-onset CRC, while Staphylococcus spp. were significantly higher in patients with sigmoid cancer and late-onset CRC. In addition, the relative abundance of Fusobacterium nucleatum was significantly higher in CRC patients.

CONCLUSION

Differentiating trends were identified at phylum, genus, and species levels, despite the inter-individual differences. In summary, this study addressed the microbial dysbiosis associated with CRC and colonic polyps groups, paving the way for a better understanding of the pathogenesis of early and late-onset CRC in Egyptian patients.

Selenium Yeast Alleviates Dextran Sulfate Sodium-Induced Chronic Colitis in Mice by Reducing Proinflammatory Cytokines and Regulating the Gut Microbiota and Their Metabolites

Background

Inflammatory bowel disease (IBD) is a chronic recurrent gastrointestinal inflammatory disease. Selenium has been reported to have therapeutic potential in IBD. Selenium yeast is a common selenium supplement that is convenient to access. This study explored the effect of selenium yeast on dextran sulfate sodium- (DSS-)induced chronic colitis in mice.

Methods

Mice were randomly divided into four groups: the control group, selenium yeast group, chronic colitis group, and chronic colitis+selenium yeast group (n=6). Mice were killed on the 26th day. The disease activity index (DAI) score and histological damage score were calculated. Cytokines, serum selenium, colonic tissue selenium, gut microbiota and their metabolites short-chain fatty acids (SCFAs) were evaluated.

Results

Selenium yeast lowered IL-1β, IL-6, TNF-α, IL-17A, IL-22 and IFN-γ (P<0.05). In addition, selenium yeast significantly elevated Turicibacter, Bifidobacterium, Allobaculum, Prevotella, Halomonas, Adlercreutzia (P<0.05), and butyric acid (P<0.05).

Conclusion

Selenium yeast could improve DSS-induced chronic colitis in mice by regulating cytokines, gut microbiota and their metabolites.

Comparison of microbial communities and the profile of sulfate-reducing bacteria in patients with ulcerative colitis and their association with bowel diseases: a pilot study

Considerable evidence has accumulated regarding the molecular relationship between gut microbiota (GM) composition and the onset (clinical presentation and prognosis of ulcerative colitis (UC)). In addition, it is well documented that short-chain fatty acid (SCFA)-producing bacteria may play a fundamental role in maintaining an anti-inflammatory intestinal homeostasis, but sulfate- and sulfite reducing bacteria may be responsible for the production of toxic metabolites, such as hydrogen sulfide and acetate. Hence, the present study aimed to assess the GM composition - focusing on sulfate-reducing bacteria (SRB) - in patients with severe, severe-active and moderate UC. Each one of the six enrolled patients provided two stool samples in the following way: one sample was cultivated in a modified SRB-medium before 16S rRNA sequencing and the other was not cultivated. Comparative phylogenetic analysis was conducted on each sample. Percentage of detected gut microbial genera showed considerable variation based on the patients' disease severity and cultivation in the SRB medium. In detail, samples without cultivation from patients with moderate UC showed a high abundance of the genera Bacteroides, Bifidobacterium and Ruminococcus, but after SRB cultivation, the dominant genera were Bacteroides, Klebsiella and Bilophila. On the other hand, before SRB cultivation, the main represented genera in patients with severe UC were Escherichia-Shigella, Proteus, Methanothermobacter and Methanobacterium. However, after incubation in the SRB medium Bacteroides, Proteus, Alistipes and Lachnoclostridium were predominant. Information regarding GM compositional changes in UC patients may aid the development of novel therapeutic strategies (e.g., probiotic preparations containing specific bacterial strains) to counteract the mechanisms of virulence of harmful bacteria and the subsequent inflammatory response that is closely related to the pathogenesis of inflammatory bowel diseases.