Prebiotic fructans have greater impact on luminal microbiology and CD3+ T cells in healthy siblings than patients with Crohn's disease: A pilot study investigating the potential for primary prevention of inflammatory bowel disease.

BACKGROUND & AIMS: Siblings of people with Crohn's disease (CD) share aspects of the disease phenotype (raised faecal calprotectin, altered microbiota), which are markers of risk for their own development of CD. The aim was to determine whether supplementation with prebiotic oligofructose/inulin induces a prebiotic response and impacts the risk phenotype in CD patients and siblings. METHODS: Patients with inactive CD (n = 19, CD activity index <150) and 12 of their unaffected siblings (with calprotectin >50 µg/g) ingested oligofructose/inulin (15 g/day) for three weeks. Faecal microbiota (qPCR), intestinal permeability (lactulose-rhamnose test), blood T cells (flow-cytometry) and calprotectin (ELISA) were measured at baseline and follow-up. RESULTS: Following oligofructose/inulin, calprotectin did not significantly change in patients (baseline mean 537 SD 535 µg/g; follow-up mean 974 SD 1318 µg/g, p = 0.08) or siblings (baseline mean 73 SD 90 µg/g: follow up mean 58 SD 72 µg/g, p = 0.62). Faecal Bifidobacteria and Bifidobacterium longum increased in patients and siblings; Bifidobacterium adolescentis and Roseburia spp. increased only in siblings. Compared with patients, siblings had a greater magnitude change in Bifidobacteria (+14.6% vs +0.4%, p = 0.028), B. adolescentis (+1.1% vs 0.0% p = 0.006) and Roseburia spp. (+1.5% vs -0.1% p = 0.004). Intestinal permeability decreased significantly in patients after oligofructose/inulin to a level that was similar to siblings. Blood T cell abundance reduced in siblings but not patients following oligofructose/inulin. CONCLUSIONS: Oligofructose/inulin supplementation did not significantly impact calprotectin, but the prebiotic effect was more marked in healthy siblings compared with patients with inactive CD and was associated with alterations in other CD risk markers. Future research should focus on dietary intervention, including with prebiotics, in the primary prevention of CD.

Azathioprine therapy selectively ablates human Vδ2⁺ T cells in Crohn's disease.

Tumor-derived and bacterial phosphoantigens are recognized by unconventional lymphocytes that express a Vγ9Vδ2 T cell receptor (Vδ2 T cells) and mediate host protection against microbial infections and malignancies. Vδ2 T cells are absent in rodents but readily populate the human intestine, where their function is largely unknown. Here, we assessed Vδ2 T cell phenotype and function by flow cytometry in blood and intestinal tissue from Crohn's disease patients (CD patients) and healthy controls. Blood from CD patients included an increased percentage of gut-tropic integrin ß7-expressing Vδ2 T cells, while "Th1-committed" CD27-expressing Vδ2 T cells were selectively depleted. A corresponding population of CD27+ Vδ2 T cells was present in mucosal biopsies from CD patients and produced elevated levels of TNFα compared with controls. In colonic mucosa from CD patients, Vδ2 T cell production of TNFα was reduced by pharmacological blockade of retinoic acid receptor-α (RARα) signaling, indicating that dietary vitamin metabolites can influence Vδ2 T cell function in inflamed intestine. Vδ2 T cells were ablated in blood and tissue from CD patients receiving azathioprine (AZA) therapy, and posttreatment Vδ2 T cell recovery correlated with time since drug withdrawal and inversely correlated with patient age. These results indicate that human Vδ2 T cells exert proinflammatory effects in CD that are modified by dietary vitamin metabolites and ablated by AZA therapy, which may help resolve intestinal inflammation but could increase malignancy risk by impairing systemic tumor surveillance.

Probiotic and prebiotic use in patients with inflammatory bowel disease: a case-control study.

BACKGROUND: The use of complementary and alternative medicine in inflammatory bowel disease (IBD) has been extensively studied. However, the use of probiotics and prebiotics is poorly documented, despite evidence of efficacy of particular probiotic strains in specific forms of IBD. METHODS: A case-control study comprising interviewer-administered questionnaires was conducted in IBD patients and healthy controls. Data regarding use and knowledge of probiotics and prebiotics, demographic, and clinical information were collected. RESULTS: In total, 334 participants (234 IBD, 100 controls) were interviewed. Significantly more IBD patients than controls had ever used probiotics to manage their health (Crohn's disease [CD] 43%, ulcerative colitis [UC] 51%, controls 21%, P < 0.001). Prebiotic use was negligible. On logistic regression analysis, having UC (odds ratio [OR] 4.30, 95% confidence interval [CI] 2.27-8.12) or CD (OR 3.05, 95% CI 1.66-5.60) were the strongest predictors of probiotic use. Within IBD patients the strongest predictor of probiotic use was current steroid use (OR 2.4, 95% CI 1.11-5.18). IBD patients had greater probiotic knowledge scores than controls (P = 0.003), although 20% of IBD probiotic users could not provide a definition of a probiotic. Less than half of IBD probiotic users discussed probiotic use with healthcare professionals, with commercial advertising being the primary source of information. CONCLUSIONS: Patients with IBD use probiotics to manage their health but frequently choose strains without evidence of efficacy in IBD. Patients rely on nonclinical sources of information and often do not disclose probiotic use to healthcare professionals. Conventional healthcare providers should inquire about probiotic use among their patients and offer evidence-based advice.