Clinical Response and Changes of Cytokines and Zonulin Levels in Patients with Diarrhoea-Predominant Irritable Bowel Syndrome Treated withBifidobacterium LongumES1 for 8 or 12 Weeks: A Preliminary Report

Bifidobacterium longum(B. longum) ES1 is a probiotic strain capable of modulating microbiome composition, anti-inflammatory activity and intestinal barrier function. We investigated the use ofB. LongumES1 in the treatment of patients with diarrhoea-predominant irritable bowel syndrome (IBS-D). Sixteen patients were treated for 8 or 12 weeks withB. LongumES1 (1 x 10(9)CFU/day). Serum zonulin and cytokines were measured at baseline (T0) and at the end of therapy (T1). Clinical response to therapy was assessed by IBS Severity Scoring System. Interleukin (IL)-6, IL-8, IL-12p70 and tumor necrosis factor (TNF) alpha levels decreased from T0 to T1, irrespective of treatment duration (p< 0.05), while zonulin levels diminished only in patients treated for 12 weeks (p= 0.036). Clinical response was observed in 5/16 patients (31%): 4/8 (50%) treated for 12 weeks and 1/8 (13%) treated for 8 weeks. Abdominal pain improved only in patients treated for 12 weeks (5/8 vs. 0/8,p= 0.025), while stool consistency improved regardless of therapy duration (p< 0.001). In conclusion, the results of this pilot study showed, in IBS-D patients treated for 12 weeks withB. longumES1, a reduction in the levels of pro-inflammatory cytokines, and intestinal permeability as well as an improvement in gastrointestinal symptoms, but further studies including a placebo-control group are necessary to prove a causal link.