title: Innate immune environment in ileal pouch mucosa: α5 defensin up-regulation as predictor of chronic/relapsing pouchitis.
abstract: Defensins are small cationic peptides with antibacterial activity expressed in Paneth cells (α-defensins) or generally in intestinal epithelial cells (β-defensins) that have a profound effect on gut microbiota. Chronic pouchitis, which occurs in 5% of patients after restorative proctocolectomy and can cause pouch failure, is associated to a significant increase of Clostridiaceae spp. The aim of this study was to gain further insight in the pathogenesis of pouch dysbiosis by exploring defensin expression. Thirty-two consecutive patients coming for follow-up endoscopy were recruited. On pouch biopsies, we cultured bacteria adherent to the mucosa and determined α- and β-defensins and toll-like receptor-4 and -2 mRNA by quantitative real-time RT-PCR. Serum and mucosal levels of IL-1β, IL-6 and TNF-α were measured with immunometric assays. Faecal lactoferrin was analysed by quantitative ELISA. After a median follow-up of 23 (IQR 20-24) months, the patients were contacted for a reassessment of current and past disease activity. During the follow-up, chronic/relapsing pouchitis was diagnosed in six patients. The mucosal level of α-5 and α-6 defensins correlated with chronic/relapsing pouchitis onset (τ = 0.30, p = 0.034 and τ = 0.28, p = 0.053, respectively). High levels of α-5 defensin resulted to be predictive of chronic/relapsing pouchitis [AUC = 74% (95% CI = 53-89%), p = 0.052]. Patients with high levels of α-5 and α-6 defensins had earlier pouchitis relapses (p = 0.009 and p = 0.034, respectively). High levels of α-5 defensin were associated to a significant risk of chronic/relapsing pouchitis [OR = 10.6 (95% CI = 1.2-97.6), p = 0.027]. At multivariate analysis, the mucosal levels of α-5 defensin and the number of CFU of mucosa-associated Clostridiaceae spp resulted to be independent predictors of chronic/relapsing pouchitis [β = 0.46 (0.18), p = 0.024 and β = 0.44 (0.18), p = 0.027, respectively]. In conclusion, chronic/relapsing pouchitis is associated to increased expression of mucosal HD-5 and to increased antimicrobial activity against Escherichia coli. In patients with chronic/relapsing pouchitis, HD-5 and TLR-4 over-expression is likely to create a hostile environment against Enterobacteriaceae, thus favouring Clostridiaceae spp by decreasing competing bacteria families.
authors: Oncological Surgery Unit, Veneto Institute of Oncology (IOV-IRCCS), via Gattamelata 64, 35128, Padua, Italy. marcoscarpa73@yahoo.it
authors: Marco
authors: M
authors: Scarpa
authors: Alessia
authors: A
authors: Grillo
authors: Melania
authors: M
authors: Scarpa
authors: Paola
authors: P
authors: Brun
authors: Carlo
authors: C
authors: Castoro
authors: Anna
authors: A
authors: Pozza
authors: Donatella
authors: D
authors: Cavallo
authors: Diego
authors: D
authors: Faggian
authors: Cesare
authors: C
authors: Ruffolo
authors: Renata
authors: R
authors: D'Incà
authors: Romeo
authors: R
authors: Bardini
authors: Ignazio
authors: I
authors: Castagliuolo
authors: Imerio
authors: I
authors: Angriman
mesh_terms: D000328:Adult; D000368:Aged; D002908:Chronic Disease; D016360:Clostridioides difficile / Q000254:growth & development; D039021:Colonic Pouches / Q000276:immunology* / Q000382:microbiology; D015169:Colony Count, Microbial; D004926:Escherichia coli / Q000254:growth & development; D005243:Feces / Q000737:chemistry; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007113:Immunity, Innate; D053583:Interleukin-1beta / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D007413:Intestinal Mucosa / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D007781:Lactoferrin / Q000032:analysis; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D019449:Pouchitis / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D011237:Predictive Value of Tests; D012333:RNA, Messenger / Q000378:metabolism*; D012008:Recurrence; D051195:Toll-Like Receptor 2 / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D015854:Up-Regulation; D023084:alpha-Defensins / Q000276:immunology* / Q000378:metabolism*; D023083:beta-Defensins / Q000378:metabolism
chemical_list: C500225:DEFA5 protein, human; C517765:DEFA6 protein, human; D053583:Interleukin-1beta; D015850:Interleukin-6; D012333:RNA, Messenger; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha; D023084:alpha-Defensins; D023083:beta-Defensins; D007781:Lactoferrin