A decrease in the abundance and biodiversity of intestinal bacteria within the dominant phylum Firmicutes has been observed repeatedly in Crohn disease patients.
Dr Sokol and colleagues from France determined the composition of the mucosa-associated microbiota of Crohn’s disease patients at the time of surgical resection and 6 months later using FISH analysis.
The research team found that a reduction of a major member of Firmicutes, Faecalibacterium prausnitzii, is associated with a higher risk of postoperative recurrence of ileal Crohn’s disease.
A lower proportion of F. prausnitzii on resected ileal Crohn mucosa also was associated with endoscopic recurrence at 6 months.
To evaluate the immunomodulatory properties of F. prausnitzii, the team analyzed the anti-inflammatory effects of F. prausnitzii in both in vitro and in vivo colitis in mice.
In Caco-2 cells transfected with a reporter gene for NF-kappaB activity, F. prausnitzii had no effect on interleukin-1beta-induced NF-kappaB activity, whereas the supernatant abolished it.
The team noted that in vitro peripheral blood mononuclear cell stimulation by F. prausnitzii led to significantly lower interleukin-12 and interferon-gamma production levels and higher secretion of interleukin-10.
|F. prausnitzii exhibits anti-inflammatory effects on colitis models|
The researchers demonstrated that oral administration of either live F. prausnitzii or its supernatant markedly reduced the severity of colitis and tended to correct the dysbiosis associated with colitis.
F. prausnitzii exhibits anti-inflammatory effects on colitis models, partly due to secreted metabolites able to block NF-kappaB activation and interleukin-8 production.
Dr Sokol’s team comments, “The results suggest that counterbalancing dysbiosis using F. prausnitzii as a probiotic is a promising strategy in Crohn’s disease treatment."