Human Intestinal Lumen and Mucosa-Associated Microbiota in Patients with Colorectal Cancer

Abstract

Recent reports have suggested the involvement of gut microbiota in the progression of colorectal cancer (CRC). We utilized pyrosequencing based analysis of 16S rRNA genes to determine the overall structure of microbiota in patients with colorectal cancer and healthy controls; we investigated microbiota of the intestinal lumen, the cancerous tissue and matched noncancerous normal tissue. Moreover, we investigated the mucosa-adherent microbial composition using rectal swab samples because the structure of the tissue-adherent bacterial community is potentially altered following bowel cleansing. Our findings indicated that the microbial structure of the intestinal lumen and cancerous tissue differed significantly. Phylotypes that enhance energy harvest from diets or perform metabolic exchange with the host were more abundant in the lumen. There were more abundant Firmicutes and less abundant Bacteroidetes and Proteobacteria in lumen. The overall microbial structures of cancerous tissue and noncancerous tissue were similar; howerer the tumor microbiota exhibited lower diversity. The structures of the intestinal lumen microbiota and mucosa-adherent microbiota were different in CRC patients compared to matched microbiota in healthy individuals. Lactobacillales was enriched in cancerous tissue, whereas Faecalibacterium was reduced. In the mucosa-adherent microbiota, Bifidobacterium, Faecalibacterium, and Blautia were reduced in CRC patients, whereas Fusobacterium, Porphyromonas, Peptostreptococcus, and Mogibacterium were enriched. In the lumen, predominant phylotypes related to metabolic disorders or metabolic exchange with the host, Erysipelotrichaceae, Prevotellaceae, and Coriobacteriaceae were increased in cancer patients. Coupled with previous reports, these results suggest that the intestinal microbiota is associated with CRC risk and that intestinal lumen microflora potentially influence CRC risk via cometabolism or metabolic exchange with the host. However, mucosa-associated microbiota potentially affects CRC risk primarily through direct interaction with the host.

Gut microbiome compositional and functional differences between tumor and non-tumor adjacent tissues from cohorts from the US and Spain

“…Additionally, tumor tissues showed a lower, although non statistically significant, diversity and species richness than adjacent tissues confirming previous studies reporting a decrease of diversity and species richness associated with CRC. 42,43 A reduced microbial diversity has been considered an undesirable effect of globalization and its concomitant diet rich in fat, protein, and sugar, and depleted of non-digestible fibers and microorganisms. Few studies have attempted to compare the gut microbiome of humans originating from different geographic locations.…”

Dynamic changes of the luminal and mucosa-associated gut microbiota during and after antibiotic therapy with paromomycin

“…Moreover, Blautia showed a reduction in mucosa-adherent samples of patients suffering from colorectal cancer and hepatic encephalopathy. [43][44][45][46] OTU abundance and potential activity do not necessarily conform to each other Abundance and potential activity are well correlated in most significant OTUs (Table 2). However, this was not the case for some OTUs representing Eubacterium, Ruminococcus torques, Blautia, C. hiranonis, Clostridium spp.…”

Fecal Bacterial Composition of the Endangered Yangtze Finless Porpoises Living Under Captive and Semi-natural Conditions

“…negatively affecting the health status of the host, such as malnutrition, colorectal cancer, obesity, diabetes, and cardiovascular disease, many of which are metabolic diseases [5,20,40,46,52]. This association between gut flora and diseases has aided in our understanding of the importance of gut microbiota in the health of the host.…”