This was a prospective, randomised, double-blind and placebo-controlled trial in children (6-18y) with moderately active distal ulcerative colitis who were concomitantly treated with oral mesalazine. The aim was to investigate the adjunctive effect of the probiotic on inflammation and cytokine expression in the rectal mucosa.
Forty children were enrolled, of whom 31 completed the 8-week study. Lactobacillus reuteri ATCC 55730 (10^10 CFU, n=16) or placebo (n=15) was administered once daily as a rectal enema before bedtime.
The score for the Mayo Disease Activity Index, DAI, (including the criteria stool frequency, bleeding, physician’s assessment of disease activity and mucosal appearance) was evaluated at baseline and on the day after the intake of study product had stopped. The Mayo DAI decreased significantly in the Lactobacillus reuteri group: 3.2 ± 1.3 vs. 8.6 ± 0.8 at baseline (p < 0.01), compared to placebo: 7.1 ± 1.1 vs. 8.7 ± 0.7 (NS); p<0.001 for mean values between groups. The histological score was significantly decreased in the active group: 0.6 ± 0.5 vs. 4.5 ± 0.6 (P < 0.01), but not in the placebo group (2.9 ± 0.8 vs. 4.6 ± 0.6, NS). The mucosal expression of cytokines was evaluated at baseline and after 8 weeks. It was significantly changed only in the Lactobacillus reuteri group: the anti-inflammatory IL-10 increased (p<0.01) whereas the pro-inflammatory IL-1beta, TNF-alpha and IL-8 all decreased (p<0.01). Clinical remission (DAI < 2.0) was achieved in 5 patients (31%) taking the probiotic but in none of the placebo subjects (p<0.05). All patients in the Lactobacillus reuteri group showed a clinical response, defined as a decrease of ≥ 2 points in the Mayo DAI, compared to 53% in the placebo group. No disease flare-ups occurred in any of the groups.
In children with active distal ulcerative colitis, rectal infusion of Lactobacillus reuteri effectively attenuated mucosal inflammation and changed the mucosal expression of cytokines to a less inflammatory pattern.