Dysbiosis of gut microbiota during fecal stream diversion in patients with colorectal cancer

Abstract

Background The effect of fecal stream diversion on the gut microbiota is still uncertain. The present study was designed to assess the effect of fecal stream diversion on the composition of the gut microbiota in patients with colorectal cancer. We included patients undergoing left-sided colorectal cancer surgery with (ileostomy group) or without (control group) diverting ileostomy. Fecal samples were collected from 10 patients in each group before surgery (t1) and after ileostomy repair in the ileostomy group and 6–12 months after the initial surgery in the control group (t2). The fecal microbiota was assessed using 16S rRNA sequencing, and changes in the composition of the fecal microbiota were compared between the two groups. Results Alpha diversity analysis revealed that the complexity of fecal microbiota decreased between t1 and t2 only in the ileostomy group. Beta diversity analysis also showed dissimilarity between t1 and t2 only in the ileostomy group. The composition of the microbiota was similar between the two groups at t1. However, at t2, the ileostomy group had lower proportion of beneficial bacteria (Lachnospiraceae, 3.8% vs. 29.9%, p < 0.001; Ruminococcaceae, 0.6% vs. 18.4%, p < 0.001; Blautia, 0.1% vs. 9.1%, p < 0.001; Faecalibacterium, 0.2% vs. 7.5%, p < 0.001) and a higher proportion of harmful bacteria (Proteobacteria, 17.9% vs. 5.1%, p = 0.006; Clostridium, 16.2% vs. 1.1%, p = 0.013; Streptococcus, 17.7% vs. 1.6%, p = 0.002) than the control group. Conclusions Fecal stream diversion was closely associated with less diversity and dysbiosis of the gut microbiota.

Association between the gut microbiota, inflammatory factors, and colorectal cancer: evidence from Mendelian randomization analysis

“…The relationship between the gut microbiota and digestive tract cancer has been a topic of considerable interest. Increasing evidence suggests that the microbiota may play a significant role in the pathogenesis of digestive tract cancer, including influencing host immune responses, metabolite production, chronic inflammation, and intestinal mucosal barrier function ( Zou et al, 2018 ; Fan et al, 2021 ; Lee et al, 2023 ). Factors such as inflammation and bacterial infection may cause a shift from the symbiotic state of the gut microbiota to a pro-carcinogenic configuration ( Weinberg and Marshall, 2019 ).…”

Elucidating the causal association between gut microbiota and intrahepatic cholangiocarcinoma through Mendelian randomization analysis

“…This gut microbiota exists in symbiosis with the gut mucosa and provides critical immunologic, metabolic, and gastrointestinal protective functions in healthy individuals ( Wang Q. et al, 2023 ). A reduction in microbial biodiversity within the gut microbiota could elevate susceptibility to diverse diseases, including the development of malignancies such as cancers ( Lee et al, 2023 ; Rajapakse et al, 2023 ). Similarly, there has been substantial research concerning the role of the gut microbiota in the occurrence and progression of ICC, as well as its implications for diagnosis and treatment strategies ( Zhang et al, 2022 ; Pomyen et al, 2023 ).…”

“…Increased Veillonellaceae may accelerate hepatic steatosis by producing carbohydrates and short-chain fatty acids. However, it can also generate carbon monoxide and hydrogen sulfide, which have toxic effects on both normal hepatocytes and bile duct cells, potentially contributing to the development of liver cancer ( Fukui, 2019 ; Demir et al, 2020 ; Lee et al, 2023 ). Although Alistipes is predominantly found in the intestinal tract of healthy humans, it has also been isolated from the bloodstream, appendix, and abdominal regions, highlighting its potential opportunistic pathogenic role in human diseases ( Shkoporov et al, 2015 ; Parker et al, 2020 ).…”