Oral administration of Lactobacillus casei DG® after ileostomy closure in restorative proctocolectomy: a randomized placebo-controlled trial (microbiota and immune microenvironment in pouchitis -MEP1)

Abstract

Pouchitis is an idiopathic inflammatory disease that may occur in ileal pouches, and it can lead to ileal pouch failure. This was a single-center, randomized, double-blinded, placebo-controlled trial that assessed the effect of Lactobacillus casei (L. casei) DG®, a probiotic strain, on the ileal pouch mucosa to determine the crosstalk between microbiota and mucosal immune system. Fifty-two patients undergoing restorative proctocolectomy were recruited and randomly assigned to receive a daily oral supplementation of L. casei DG® (n = 26) or placebo (n = 26) for 8 weeks from the ileostomy closure (T0) to a pouch endoscopy after 8 weeks (T1) and 1 year (T2). Ileal pouch mucosa samples were collected at T0, T1, and T2. At T1, the L. casei DG®-supplemented group showed a significant reduction of inflammatory cytokines levels compared to T0 baseline levels in the pouch mucosa, whereas in the placebo group cytokines levels resulted stable. In conclusion, probiotic manipulation of mucosal microbiota by L. casei DG®-supplementation after stoma closure in patients who underwent restorative proctocolectomy has a beneficial impact on the ileal pouch microenvironment. Registration number: NCT03136419 (http://www.clinicaltrials.gov).

Keywords: Probiotics; ileal pouch-anal anastomosis; inflammatory bowel disease; microbiota; pouchitis.

Figure 1.

CONSORT flow diagram for enrollment, allocation, follow-up, and analysis.

Figure 2.

Inflammatory cytokines network in the pouch. (a) IL1β, IL6, and TNFα levels within pouch mucosa at T1 in the two arms of the study. (b) IL1β, IL6, and TNFα levels within pouch mucosa at T0 and T1 in the two arms of the study.

Figure 3.

Cells subpopulations within pouch mucosa. (a) Frequency of patients with positive and negative delta T1-T0 of activated dendritic cells in the two arms of the study. (b) Correlation between activated dendritic cell rate and activated T helper lymphocytes rate. (c) CD1a+CD80+ cells rate and MFI, CD163+CD80+ cells MFI, and CD163+CD40+ cells rate in pouch mucosa at T0 and T1 in the two arms of the study.

Figure 4.

Mucosa-adherent microbiota in the pouch. Box plot of T0 and T1 α-diversity in placebo and L. casei DG treated patients at the ASV level according to Pielou Evenness (a), richness (b), and Shannon Index (c). Plot of Bray-Curtis β-diversity Index at T0 and T1 in terms of ASV according to treatment (d). (e) Frequency of patients with positive and negative delta T1-T0 of Bifidobacterium spp. In the two arms of the study. (f) Relative abundance of the 30 most abundant genera, presented according to randomization group at T0 and T1.

Figure 5.

Clinical effect of L. casei DG supplementation. (a) PDAI and mPDAI at T1 in the two arms of the study (b) high Δ_T1-T0 CD1a+Cd80+ and (c) Δ_T1-T0CD163+Cd80+ cell MFI levels are associated with pouchitis onset. Kaplan-Meier survival curves of high and low Δ_T1-T0 CD1a+Cd80+ and CD163+Cd80+ cell MFI. (d) Number of pouchitis episodes and of (e) pouchitis duration (weeks) in patients with high and low Δ_T1-T0 CD1a+Cd80+ and CD163+Cd80+ cell MFI.