S. Cenni

Cytokine production profile in intestinal mucosa of paediatric inflammatory bowel disease

In the recent years, the incidence of inflammatory bowel disease (IBD) has dramatically increased in young subjects, however, the pathogenesis of paediatric IBD is poorly investigated. In this study we aimed to evaluate the cytokine pattern and the phenotype of cytokine producing cells in the intestinal mucosa of paediatric patients affected by Crohn’s disease (CD) or ulcerative colitis (UC) and of non-IBD healthy controls (HC). Cytokine (IL-15, TNF-α, INF-γ) production was analyzed at basal condition and after mitogen stimulation either intracellularly by flow cytometry or in intestinal cell culture supernatants by enzyme-linked immunosorbent assay (ELISA). A higher frequency of enterocytes (EpCam+ cells) was observed in UC patients compared to CD or HC. An expansion of enterocytes producing IL-15 and TNF-α were found in IBD patients compared to HC. A marked expression of IL-15 in the intestinal epithelium of IBD patients was further confirmed by immunohistochemistry. Myeloid dendritic (CD11c+) cells producing TNF-α and INF-γ were increased in IBD biopsies. Unexpectedly, only after a strong mitogen stimulus, as phytohaemagglutinin, the frequency of CD3+ cells producing IFN-γ was increased in IBD compared to control intestinal mucosa. Interestingly, functional studies performed on organ cultures of intestinal biopsies with neutralizing anti-IL-15 monoclonal antibody showed a marked reduction of mononuclear cell activation, proliferation of crypt enterocytes, as well as a reduction of TNF-α release in organ culture supernatants. In conclusion, we found that in the gut mucosa of IBD children both enterocytes and dendritic cells produce proinflammatory cytokines. The over-expression of IL-15 by enterocytes in IBD intestine and the reduced IBD inflammation by IL-15 blockage suggests that this cytokine could be a therapeutic target in IBD.

Impact of Environmental and Familial Factors in a Cohort of Pediatric Patients with Inflammatory Bowel Disease.

Objectives: The primary role of environment on inflammatory bowel disease (IBD) onset has been recently stressed. We aimed to investigate the effect of environmental factors in an IBD pediatric cohort. Methods: A total of 467 subjects (264 IBD and 203 controls) were enrolled. All patients underwent a questionnaire including 5 different groups of environmental risk factors: family history of IBD and autoimmune diseases, perinatal period, home amenities and domestic hygiene, childhood diseases and vaccinations, and diet. Results: In a multivariate model, mothers degree (odds ratio [OR]: 5.5; 2.5–11.6), duration of breast feeding >3rd month (OR: 4.3; 1.6–10.5), fathers employment (OR: 3.7; 1.2–8.7), gluten introduction <6th month (OR: 2.8; 1.5–5), number of siblings <2 (OR: 2.8; 1.5–5.3), and family history of autoimmune diseases (OR: 2.7; 1.4–5.3) were significant risk factors for Crohn disease. Low adherence to Mediterranean diet (OR: 2.3; 1.2–4.5), gluten introduction <6th month (OR: 2.8; 1.6–4.9), and number of siblings <2 (OR: 2; 1.1–3.6) were significant risk factors for ulcerative colitis. Owning pets (OR: 0.3; 0.1–0.7) and bed sharing (OR: 0.2; 0.1–0.6) were protective factors for Crohn disease, whereas owning pets (OR: 0.4; 0.2–0.8) and family parasitosis (OR: 0.07; 0.01–0.4) were protective factors for ulcerative colitis. Conclusions: Our study confirms that environmental factors are closely linked to IBD onset and may partly explain IBD rise in developed countries.

Cannabinoid Receptor 2 Functional Variant Contributes to the Risk for Pediatric Inflammatory Bowel Disease

Goals: We conducted a case-control association analysis to establish the role of a common CB2 functional variant, Q63R, in the susceptibility to inflammatory bowel disease (IBD). Background: Endocannabinoids may limit intestinal inflammation through cannabinoid receptor 1 and/or 2 (CB1, CB2). Study: We genotyped 217 pediatric IBD patients [112 Crohn’s disease (CD), 105 ulcerative colitis (UC)] and 600 controls for the CB2-Q63R variant by Taqman assay. Data were collected from clinical records on age at diagnosis, disease activity, duration and location, extraintestinal manifestations, therapy, clinical relapses, and need for surgery. Results: We found a significant association of the CB2-R63 variant with IBD (allele frequencies, P=0.04; genotype distributions, P=0.0006), in particular with CD (allele frequencies, P=0.002; genotype distributions, P=0.00005) and with UC only for genotype distributions (P=0.03). RR carriers showed an increased risk for developing IBD [odds ratio (OR)=1.82; P=0.0002 for IBD; OR=2.02; P=10−1 for CD; OR=1.63; P=0.02 for UC at 95% confidence interval]. Upon genotype-phenotype evaluation, RR patients showed an increased frequency of moderate-to-severe disease activity at diagnosis in the case of both CD and UC (P=0.01 and P=0.02, respectively) and also an earlier clinical relapse in UC (P=0.04). In UC, all the clinical features related to the CB2 risk allele were still significantly associated with the variant when analyzed using a multivariate logistic regression model (P=0.001). Conclusions: The CB2-Q63R variant contributes to the risk for pediatric IBD, in particular CD. The R63 variant is associated with a more severe phenotype in both UC and CD. Taken together, our data point toward the involvement of the CB2 receptor in the pathogenesis and clinical features of pediatric IBD.

Does Azathioprine induce endoscopic and histologic healing in pediatric inflammatory bowel disease? A prospective, observational study

BACKGROUND The new concept of disease remission for pediatric inflammatory bowel diseases (IBD) implies the achievement of mucosal healing. AIMS We aimed to evaluate endoscopic and histologic healing in children with Ulcerative Colitis (UC) and Crohns disease (CD) in clinical remission after 52 weeks of Azathioprine. METHODS From December 2012 to July 2015 we prospectively enrolled IBD children starting Azathioprine. Enrolled patients in clinical remission underwent colonoscopy after 52 weeks. Macroscopic assessment was described with Mayo score and the simplified endoscopic score for UC and CD, respectively. For microscopic assessment, an average histology score was used. Data on inflammatory markers and fecal calprotectin were also collected. RESULTS Fourty-seven patients were included in the analysis. Endoscopic healing was detected in 20/26 (76.9%) UC children and 10/21 (47.6%) CD patients. Median Mayo score and simplified endoscopic score were significantly decreased at week 52 (p<0.001; p=0.005). Median average histology score was not significantly different at week 52 in both diseases. Fecal calprotectin was directly correlated with simplified endoscopic score (T0: r=0.4, p=0.05; T52: r=0.5, p=0.01), but not with Mayo score. No correlation was found between endoscopic and histologic scores. CONCLUSIONS IBD children under Azathioprine reach endoscopic healing, but not histological remission.