Carrageenan Gum and Adherent Invasive Escherichia coli in a Piglet Model of Inflammatory Bowel Disease: Impact on Intestinal Mucosa-associated Microbiota

Abstract

Inflammatory bowel diseases (IBD) including Crohn's disease (CD), and ulcerative colitis (UC), are chronic conditions characterized by chronic intestinal inflammation. Adherent invasive Escherichia coli (AIEC) pathotype has been increasingly implicated in the etiopathogenesis of IBD. In a 21-day study, we investigated the effects of AIEC strain UM146 inoculation on microbiota profile of the ileal, cecal, ascending and descending colon in a pig model of experimental colitis. Carrageenan gum (CG) was used to induce colitis in weaner piglets whereas AIEC strain UM146 previously isolated from a CD patient was included to investigate a cause or consequence effect in IBD. Treatments were: (1) control; (2) CG; (3) AIEC strain UM146; and (4) CG+UM146. Pigs in groups 2 and 4 received 1% CG in drinking water from day 1 of the study while pigs in groups 3 and 4 were inoculated with UM146 on day 8. Following euthanization on day 21, tissue mucosal scrapings were collected and used for DNA extraction. The V4 region of bacterial 16S rRNA gene was then subjected to Illumina sequencing. Microbial diversity, composition, and the predicted functional metagenome were determined in addition to short chain fatty acids profiles in the digesta and inflammatory cytokines in the intestinal tissue. CG-induced colitis decreased bacterial species richness and shifted community composition. At the phylum level, an increase in Proteobacteria and Deferribacteres and a decrease in Firmicutes, Actinobacteria, and Bacteroidetes were observed in CG and CGUM146 compared to control and UM146. The metabolic capacity of the microbiome was also altered in CG and CGUM146 compared to UM146 and control in the colon. We demonstrated that CG resulted in bacterial dysbiosis and shifted community composition similar to what has been previously observed in IBD patients. However, AIEC strain UM146 alone did not cause any clear changes compared to CG or control in our experimental IBD pig model.

Acute dextran sulfate sodium (DSS)‐induced colitis promotes gut microbial dysbiosis in mice

“…However, data on members of p. Bacteroidetes are more ambiguous, and thus, inconsistent findings have been reported for their presence in IBD compared to healthy controls [72][73][74][75][76][77]. Moreover, although still under investigations, some bacteria that were characteristic of DSS in the fecal samples, such as Helicobacter hepaticus and the f. Enterobacteriaceae, specifically g. Escherichia, have been implicated in IBD patients and in animal models of IBD [8,31,32,37,76,78]. Similar findings for increased levels of Enterobacteriaceae have also been reported in murine colitis, and after antibiotic treatment or infection by enteric pathogens [44,79,80].…”

Adherent-invasive Escherichia coli in inflammatory bowel disease

“…Western diets are rich in polysaccharides and contain high levels of maltodextrin, which could contribute to dysbiosis and IBD susceptibility 180. Additionally, carrageenan gum (sulfated polysaccharide used as a stabiliser and bulking agent)181 and the commonly used emulsifiers polysorbate-80114 and carboxymethylcellulose,182 ha also been shown to influence bacterial adhesion, host mucosal homeostasis and gut microbiota composition and localization. This promotes the development of low-grade inflammation and favours AIEC colonisation of the gut mucosa.…”

Home Enteral Nutrition: Updates, Trends, and Challenges

“…A study of children who had undergone fundoplication showed improvement in gagging, retching, and bowel function after being transitioned to pureed food diets via gastrostomy bolus feeds 21 . Additionally, there is new evidence that large quantities of carrageenan, emulsifiers, and maltodextrin in the diet have negative effects on the microbiota, 22 , 23 particularly among patients with inflammatory bowel disease.…”