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Inflammatory bowel diseases (IBDs) can be associated with various musculoskeletal (IBD-MSK) manifestations that could be difficult to classify for gastroenterologists. We aimed to evaluate the characteristics of patients with IBD-MSK and the prevalence of spondyloarthritis (SpA). In this observational cross-sectional study, we included patients with IBD-MSK complaints (peripheral or back pain). All patients underwent a standardized rheumatology evaluation including clinical, biological and imaging evaluations (MRI of spine and sacroiliac joints and ultrasonography of enthesis). We included 183 IBD patients (60.7% women; median [interquartile range] age 45 [36-56] years); 159 (87%) had joint pain. In 43 (23.5%) and 25/175 (14.3%) patients, enthesis abnormalities were found on ultrasonography and sacroiliitis on MRI, respectively. SpA was diagnosed in 54 (29.5%) patients. IBD-related arthralgia and degenerative spine disease were diagnosed in 105 (57.4%) and 72 (39.3%) patients. Sixteen (29.6%) SpA patients initiated a new conventional synthetic disease modifying anti-rheumatic drug (DMARD). A biologic DMARD was initiated in 10 patients or changed in 3. More than half of IBD-MSK patients had IBD-related arthralgia, and about one-third had definite SpA. Ultrasonography of enthesis and systematic MRI of sacroiliac joints seem useful for SpA classification and differential diagnosis in these patients who often have musculoskeletal pain complaints. Therapeutics were changed in most patients, which highlights the need for a multidisciplinary approach for managing IBD with extra-intestinal symptoms., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: Vedolizumab clinical decision support tool (VDZ-CDST) predicts response to vedolizumab, but whether this tool also predicts efficacy of other drugs in Crohn's disease (CD) is unknown. This study aimed to assess the value of VDZ-CDST to predict vedolizumab and ustekinumab efficacy in patients with CD., Patients and Methods: We included consecutive CD patients refractory or intolerant to anti-TNF who started either vedolizumab or ustekinumab in 5 university hospitals between May 2014 and August 2018. The main end points were the rates of clinical remission and steroid-free clinical remission (SFCR) in each group of VDZ-CDST at week 48., Results: One hundred eighty patients were included; 94 received vedolizumab (VDZ-CDST ≤13: 32; VDZ-CDST >13 and ≤19: 52; VDZ-CDST >19: 10), and 86 received ustekinumab (VDZ-CDST ≤13: 16; VDZ-CDST >13 and ≤19: 60; VDZ-CDST >19: 10). At week 48 in the vedolizumab group, clinical remission and SFCR were reached in 9.4% with a VDZ-CDST ≤13, in 38.5% and 28.8% with a VDZ-CDST >13 and ≤19, respectively, and in 80.0% with a VDZ-CDST >19 (P < 0.0001 and P < 0.0001, respectively). In the ustekinumab cohort, clinical remission and SFCR were reached in 43.8% and 37.5% with a VDZ-CDST ≤13, in 55.0% and 50.0% with a VDZ-CDST >13 and ≤19, and 50.0% with a VDZ-CDST >19, respectively (P = 0.65 and P = 0.46, respectively). VDZ-CDST identified SFCR with an area under the curve of 0.69 (95% CI, 0.57-0.82) for vedolizumab and 0.52 (95% CI, 0.40-0.65) for ustekinumab., Conclusion: The VDZ-CDST predicts clinical remission and SFCR at week 48 for vedolizumab but not for ustekinumab in CD patients refractory or intolerant to anti-TNF., (© 2021 Crohn’s & Colitis Foundation. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Autologous hematopoietic cell transplantation (AHCT) is a new treatment option for patients with severe autoimmune diseases (AD), based on the use of intensive or myeloablative chemotherapy to eradicate the pathogenic autoreactive immune cells and to allow the installation of a new and tolerant immune system during immune reconstitution process. Immune reconstitution analysis after AHCT is required for patients clinical follow-up and to further identify biological and immunological markers of the clinical response to develop individualized AHCT protocols. These MATHEC-SFGM-TC good clinical practice guidelines were developed by a multidisciplinary group of experts including members of the french reference center for stem Cell Therapy in Auto-immune Diseases (MATHEC), hematologists from the French speaking Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC) and experts in immune monitoring and biobanking. The objectives are to provide practical recommandations for immune monitoring and biobanking of samples in patients with AD undergoing AHCT, for routine care purposes and investigational studies., (Copyright © 2021 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.)

Background: Ileal pouch-anal anastomosis (IPAA) is the standard of care after total proctocolectomy for ulcerative colitis (UC). However, inflammation often develops in the pouch, leading to acute or recurrent/chronic pouchitis (R/CP). MicroRNAs (miRNA) are used as accurate diagnostic and predictive biomarkers in many human diseases, including inflammatory bowel diseases. Therefore, we aimed to identify an miRNA-based biomarker to predict the occurrence of R/CP in patients with UC after colectomy and IPAA., Methods: We conducted a retrospective study in 3 tertiary centers in France. We included patients with UC who had undergone IPAA with or without subsequent R/CP. Paraffin-embedded biopsies collected from the terminal ileum during the proctocolectomy procedure were used for microarray analysis of miRNA expression profiles. Deep neural network-based classifiers were used to identify biomarkers predicting R/CP using miRNA expression and relevant biological and clinical factors in a discovery cohort of 29 patients. The classification algorithm was tested in an independent validation cohort of 28 patients., Results: A combination of 11 miRNA expression profiles and 3 biological/clinical factors predicted the outcome of R/CP with 88% accuracy (area under the curve = 0.94) in the discovery cohort. The performance of the classification algorithm was confirmed in the validation cohort with 88% accuracy (area under the curve = 0.90). Apoptosis, cytoskeletal regulation by Rho GTPase, and fibroblast growth factor signaling were the most dysregulated targets of the 11 selected miRNAs., Conclusions: We developed and validated a computational miRNA-based algorithm for accurately predicting R/CP in patients with UC after IPAA., (© 2021 Crohn’s & Colitis Foundation. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Aims: The aims of this study were to describe outcomes in patients with Crohn's disease who fail anti-tumor necrosis factor (TNF) and either vedolizumab or ustekinumab., Methods: Multicenter, retrospective study of 100 patients with Crohn's disease who failed anti-TNF and either vedolizumab or ustekinumab from 2015 to 2019. Using multivariable Cox regression, we sought to identify factors associated with need for surgery., Results: 75 patients received a third line treatment, resulting in 23 (30.7%) clinical remission at week 48. Among the 71 patients included after vedolizumab failure, 46 received ustekinumab, resulting in 46 (28.3%) clinical remission; 13 patients were retreated with an anti-TNF, resulting in 13 (46.2%) clinical remission. Among the 29 patients included after ustekinumab failure, 12 were retreated with an anti-TNF, resulting in 2 (16.7%) clinical remission. The rate of surgery-free survival at 48 weeks was 76.5% (95% confidence interval 68.4% - 85.4%). In multivariable analysis, ileal disease localization (hazard ratio 9.0, 95% confidence interval 1.0-81.9) was associated with a higher risk of surgery., Conclusion: In patients with Crohn's disease who have failed anti-TNF and either vedolizumab or ustekinumab, at week 48, the surgery rate is 23.5% and the remission rate after a third line biologic therapy is 30.7%., Competing Interests: Declaration of Competing Interest LK, JK and AM declare no competing interest. AA received honoraria from Abbvie, Hospira, Takeda, Gilead, Biocodex, Janssen, Tillotts, Ferring and MSD. XT received honoraria from Abbvie, MSD, Takeda, Ferring, Norgine and Janssen. MA received honoraria from Abbvie, MSD, Janssen, Takeda, Pfizer, Novartis, Ferring, Tillotts, Celgene and Genentech/Roche. YB received honoraria from Abbvie, Biogaran, Boehringer Ingelheim, Celgene, Ferring, Gilead, Hospira, Janssen, Mayoly-Spindler, MSD, Norgine, Pfizer, Roche, Samsung Bioepis, Sandoz, Sanofi, Shire, Takeda, UCB. LB received honoraria from Janssen, Pfizer, Allergan, AbbVie, Janssen, MSD, Ferring Pharmaceuticals, Mayoly-Spindler, Takeda and Tillotts, and research support from Abbott, Ferring Pharmaceuticals, Hospira-Pfizer, Janssen, MSD, Takeda and Tillotts. FC received honoraria from Amgen, BMS, Enterome, Ferring, Janssen, Medtronic, Pfizer, Pharmacosmos and Roche as well as lecture fees from Abbvie, Astra, BMS, Ferring, Janssen, MSD, Pfizer, Pileje, Takeda and Tillotts., (Copyright © 2020. Published by Elsevier Ltd.)

Background: There is no head-to-head trial comparing ustekinumab and vedolizumab in patients with Crohn's disease (CD) refractory to anti-tumour necrosis factor (anti-TNF)., Aim: To compare the effectiveness and safety of ustekinumab and vedolizumab in patients with CD refractory to anti-TNF in a multicentre retrospective observational cohort., Methods: All consecutive patients with CD refractory or intolerant to anti-TNF who initiated either vedolizumab or ustekinumab were included between May 2014 and August 2018. Clinical remission, steroid-free clinical remission (SFCR) and treatment persistence were assessed at week 48 with intention-to-treat analysis and propensity scores weighted comparison., Results: A total of 239 patients were included, 107 received ustekinumab and 132 received vedolizumab. At week 48, ustekinumab was associated with a higher clinical remission rate (54.4% vs 38.3%; odds ratios, OR = 1.92, 95% CI [1.09-3.39]) and treatment persistence (71.5% vs 49.7%; OR = 2.54, 95% CI [1.40-4.62]) than vedolizumab. The rate of SFCR did not differ significantly between ustekinumab and vedolizumab (44.7% vs 34.0%; OR = 1.57, 95% CI [0.88-2.79]). Subgroup analyses showed that ustekinumab was associated with a higher clinical remission rates at week 48 in patients with ileal location (OR = 3.49, 95% CI [1.33-9.17) and penetrating behaviour (OR = 6.58, 95% CI [1.91-22.68]). Regardless of the treatment group, combination therapy at initiation was associated with a higher clinical remission rate at week 48 (OR = 1.93, 95% CI [1.09-3.43])., Conclusion: This study suggests that ustekinumab is associated with a higher rate of clinical remission and treatment persistence than vedolizumab after 48 weeks of follow-up, in patients with CD refractory or intolerant to anti-TNF. The rate of SFCR was not significantly different., (© 2020 John Wiley & Sons Ltd.)

T cell clonal expansions are present in the inflamed mucosa of patients with Crohn's disease (CD) and may be implicated in postoperative recurrence after ileocolonic resection., Methods: T cell receptor (TCR) analysis was performed in 57 patients included in a prospective multicentre cohort. Endoscopic recurrence was defined by a Rutgeerts score >i0. DNA and mRNA were extracted from biopsies collected from the surgical specimen and endoscopy, and analysed by high throughput sequencing and microarray, respectively., Results: TCR repertoire in the mucosa of patients with CD displayed diverse clonal expansions. Active smokers at time of surgery had a significantly increased proportion of clonal expansions as compared with non-smokers (25.9%vs17.9%, p=0.02). The percentage of high frequency clones in the surgical specimen was significantly higher in patients with recurrence and correlated with postoperative endoscopic recurrence (area under the curve (AUC) 0.69, 95% CI 0.54 to 0.83). All patients with clonality above 26.8% (18/57) had an endoscopic recurrence. These patients with a high clonality were more frequently smokers than patients with a low clonality (61% vs 23%, p=0.005). The persistence of a similar TCR repertoire at postoperative endoscopy was associated with smoking and disease recurrence. Patients with high clonality showed increased expression of genes associated with CD8 T cells and reduced expression of inflammation-related genes. Expanded clones were found predominantly in the CD8 T cell compartment., Conclusion: Clonal T cell expansions are implicated in postoperative endoscopic recurrence. CD patients with increased proportion of clonal T cell expansions in the ileal mucosa represent a subgroup associated with smoking and where pathogenesis appears as T cell driven., Trial Registration Number: NCT03458195., Competing Interests: Competing interests: MA received honoraria from Abbvie, MSD, Janssen, Takeda, Pfizer, Novartis, Ferring, Tillots, Celgene and Genentech/Roche. SN received honoraria from MSD, Abbvie, Takeda, Janssen, HAC Pharma, Tillots, Ferring and Novartis. AB received honoraria from MSD, Abbvie, Ferring, Takeda, Vifor Pharma, Sanofi‐Aventis, Hospira and Janssen. BP received honoraria from AbbVie, MSD, Takeda, Janssen, Bioagaran and Ferring. MF received honoraria from AbbVie, MSD, Takeda, Janssen, Pfizer, Ferring and Boehringer. HS received unrestricted study grants: Danone, Biocodex and Enterome; board membership, consultancy, or lecture fees: Carenity, Abbvie, Astellas, Danone, Ferring, Mayoly Spindler, MSD, Novartis, Roche, Tillots, Enterome, Maat, BiomX, Biose, Novartis and Takeda; cofunder of Nextbiotix. XT received honoraria from Abbvie, MSD, Takeda, Ferring, Norgine and Janssen. PS received honoraria from Takeda, MSD, Biocodex, Ferring and Abbvie, and non-financial support from Takeda. CA, MN, HB, VC, AMC, AS, CS and NB declare no competing interest., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Background and Aims: Faecal diversion [FD] can be proposed in patients with refractory anoperineal Crohn's disease [APCD]. This study aimed to assess long-term results of this strategy, following the advent of the anti-tumour necrosis factor [TNF] era., Methods: All patients who underwent FD for refractory APCD between 2005 and 2017 were included, excluding patients with a history of ileal pouch-anal anastomosis. A multivariate analysis regarding absence of stoma reversal [SR] was performed., Results: A total of 65 consecutive patients who underwent FD for APCD (comprising anoperineal fistula [n = 40, 62%], rectovaginal fistula [n = 21, 32%], fissures and/or ulceration [n = 9, 14%], and/or anal stricture [n = 5, 8%]) were included. At the time of FD, 34 patients [52%] presented with small bowel Crohn's disease [CD] involvement, 29 [45%] with colonic involvement, and 19 [29%] with rectal involvement. Following FD, 54 patients [83%] were treated with anti-TNF therapy, prescribed for isolated APCD [n = 10, 15%] or luminal CD with APCD [n = 44, 68%]. After a mean follow-up of 49 ± 29 [7-120] months, SR was not possible in 32 patients [49%], including 17 patients [26%] requiring a subsequent proctectomy with abdominoperineal excision. In multivariate analysis, rectal CD involvement was the only independent factor associated with a reduced rate of SR (odds ratio: 4.0 [1.153-14.000]; p = 0.029), and anti-TNF therapy had no impact on SR rate., Conclusions: FD can be performed in selected patients with refractory APCD, to avoid abdominoperineal resection. However, this strategy should be proposed with caution in patients presenting with rectal CD involvement. Anti-TNF therapy has no impact on SR rate., (Copyright © 2018 European Crohn’s and Colitis Organisation (ECCO). Published by Oxford University Press. All rights reserved. 
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Yersinia are common contaminants of food products, but their prevalence in the human gut is poorly documented. Yersinia have been implicated in Crohn's Disease (CD, an inflammatory bowel disease) however their role in CD is controversial. We performed highly sensitive PCR assays of specific sequences for the gyrB gene of Y. aldovae, Y. bercovieri, Y. enterocolitica, Y. intermedia, Y. mollaretii and the inv gene of Y. pseudotuberculosis . We analyzed a total of 470 ileal samples taken from 338 participants (262 CD patients and 76 controls) belonging to three independent cohorts. All patients and controls were phenotyped and genotyped for the main CD susceptibility variants: NOD2, ATG16L1 , and IRGM . Yersinia were found in 7.7% of ileal samples (respectively 7.9 and 7.6% in controls and CD patients) corresponding to 10% of participants (respectively 11.8 and 9.5% in controls and CD patients). Y. enterocolitica, Y. pseudotuberculosis and Y. intermedia were the most frequently identified species. The bacteria were more frequent in resected specimens, lymph nodes and Peyer's patches. Yersinia were no more likely to be detected in CD tissues than tissues from inflammatory and non-inflammatory controls. CD patients treated with immunosuppressants were less likely to be Yersinia carriers. In conclusion, this work shows that Yersinia species are frequently found at low levels in the human ileum in health and disease. The role of Yersinia species in this ecosystem should now be explored.

Backgrounds and Aims: The effect of cigarette smoking [CS] is ambivalent since smoking improves ulcerative colitis [UC] while it worsens Crohn's disease [CD]. Although this clinical relationship between inflammatory bowel disease [IBD] and tobacco is well established, only a few experimental works have investigated the effect of smoking on the colonic barrier homeostasis focusing on xenobiotic detoxification genes., Methods: A comprehensive and integrated comparative analysis of the global xenobiotic detoxification capacity of the normal colonic mucosa of healthy smokers [n = 8] and non-smokers [n = 9] versus the non-affected colonic mucosa of UC patients [n = 19] was performed by quantitative real-time polymerase chain reaction [qRT PCR]. The detoxification gene expression profile was analysed in CD patients [n = 18], in smoking UC patients [n = 5], and in biopsies from non-smoking UC patients cultured or not with cigarette smoke extract [n = 8]., Results: Of the 244 detoxification genes investigated, 65 were dysregulated in UC patients in comparison with healthy controls or CD patients. The expression of ≥ 45/65 genes was inversed by CS in biopsies of smoking UC patients in remission and in colonic explants of UC patients exposed to cigarette smoke extract. We devised a network-based data analysis approach for differentially assessing changes in genetic interactions, allowing identification of unexpected regulatory detoxification genes that may play a major role in the beneficial effect of smoking on UC., Conclusions: Non-inflamed colonic mucosa in UC is characterised by a specifically altered detoxification gene network, which is partially restored by tobacco. These mucosal signatures could be useful for developing new therapeutic strategies and biomarkers of drug response in UC., (Copyright © 2016 European Crohn’s and Colitis Organisation (ECCO). Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com)

Background: Aside from cases of backwash ileitis, the ileal mucosa of patients with ulcerative colitis (UC), an idiotypic inflammatory bowel disease, has received little attention despite the fact that colitis is known to trigger alterations in morphology and/or functions of the small intestine remotely., Methods: The ileal mucosa was studied in patients with UC and in a spontaneous model of colitis (Il10/Nox1 mice) mimicking the histological and clinical features of UC and was also studied in acute and chronic murine models of chemically induced colitis. Proliferation and apoptosis were assessed using morphological and immunohistological methods and Western blot analysis. Peyer's patch immune cell subsets were analyzed. Cytokines levels were quantified using quantitative PCR and Luminex xMAP technology. Total RNA from isolated ileal crypts was used for whole genome transcriptome analysis., Results: The most striking features were an increased ileal crypt length associated with an enhanced cell proliferation of the transit-amplifying cells along with activation of the Wnt/β-catenin and MAPkinase pathways. These changes did not result from intestinal inflammation as assessed by histology and/or pro-inflammatory cytokine expression levels. The increased proliferation rate was dependent on the duration but not on the severity of colitis and was observed in different mouse models of colitis, including the Il10/Nox1 model and 2,4,6-trinitrobenzenesulfonic acid-treated mice. Interestingly, the ileal mucosa of patients with UC also displayed longer crypts and enhanced cell proliferation compared with control patients., Conclusions: These data show that despite the absence of inflammation in the small intestine, alterations in the ileal mucosa homeostasis are present in UC.

Background and Aims: Digestive perianastomotic ulcerations (DPAU) have been occasionally reported as late complications of neonatal or childhood surgery., Methods: We report here a series of 14 new cases., Results: Cases were revealed by severe anemia, diarrhea, abdominal pain and growth failure in average 11.5 years after surgery. Ulcerations were most often multiple (n=11), located on the upper part of ileocolonic anastomoses (n=12) and difficult to treat. No granulomas were seen but lymphoid follicles were frequent. In addition, either ASCA or ANCA were positive in 4/9 tested patients and 8/11 genotyped patients exhibited a NOD2 mutation (P<0.0002 when compared to French healthy controls)., Conclusion: Altogether, these findings argue for common physiopathological features between DPAU and Crohn's disease and for a prospective follow-up of selected operated children to explore the early events involved in gut inflammatory lesions., (Copyright © 2014 European Crohn's and Colitis Organisation. Published by Elsevier B.V. All rights reserved.)

Ulcerative colitis (UC) is a chronic inflammatory bowel disease affecting the rectum which progressively extents. Its etiology remains unknown and the number of treatments available is limited. Studies of UC patients have identified an unbalanced endoplasmic reticulum (ER) stress in the non-inflamed colonic mucosa. Animal models with impaired ER stress are sensitive to intestinal inflammation, suggesting that an unbalanced ER stress could cause inflammation. However, there are no ER stress-regulating strategies proposed in the management of UC partly because of the lack of relevant preclinical model mimicking the disease. Here we generated the IL10/Nox1dKO mouse model which combines immune dysfunction (IL-10 deficiency) and abnormal epithelium (NADPH oxidase 1 (Nox1) deficiency) and spontaneously develops a UC-like phenotype with similar complications (colorectal cancer) than UC. Our data identified an unanticipated combined role of IL10 and Nox1 in the fine-tuning of ER stress responses in goblet cells. As in humans, the ER stress was unbalanced in mice with decreased eIF2α phosphorylation preceding inflammation. In IL10/Nox1dKO mice, salubrinal preserved eIF2α phosphorylation through inhibition of the regulatory subunit of the protein phosphatase 1 PP1R15A/GADD34 and prevented colitis. Thus, this new experimental model highlighted the central role of epithelial ER stress abnormalities in the development of colitis and defined the defective eIF2α pathway as a key pathophysiological target for UC. Therefore, specific regulators able to restore the defective eIF2α pathway could lead to the molecular remission needed to treat UC.

Background & Aims: Ulcerative colitis (UC) is a chronic inflammatory disorder that affects the colonic epithelium. Epidemiology studies indicate an environmental component is involved in pathogenesis, although the primary changes in the digestive epithelium that cause an uncontrolled inflammatory response are not known. Animal studies have shown that altered endoplasmic reticulum (ER) stress response initiates intestinal inflammation in epithelial tissues, but abnormalities associated with ER stress have not been identified in patients with UC., Methods: Using immunoblotting, real-time polymerase chain reaction, immunohistochemistry, and immunofluorescence analyses, we assessed ER stress signaling in uninflammed colonic mucosa from patients with UC and controls. Genome-wide microarray analysis of actively translated polysome-bound messenger RNA was performed using samples of unaffected mucosa from patients with UC, and data were compared with those from controls., Results: Inositol-requiring kinase and activating transcription factor signaling pathways were activated in inactive colonic epithelium from patients with UC; these mediate proinflammatory and regenerative responses. Blocking phosphorylation of the translation initiation factor 2 (eIF2α), which mediates the integrated stress response, deregulated initiation of translation and reduced the numbers of stress granules in colonic epithelial cells from patients with UC. Genome-wide microarray analysis of actively translated, polysome-bound messenger RNA from patients revealed changes in protein translation that altered colonic epithelial barrier function (levels of detoxification and antioxidant enzymes and proteins that regulate the cell cycle, cell-cell adhesion, and secretion), compared with controls., Conclusions: Colonic mucosa samples from patients with UC have defects in the eIF2α pathway that controls protein translation and the cell stress response. This pathway might be investigated to identify new therapeutic targets for patients with UC., (Copyright © 2011 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Background: The aim was to evaluate the value of magnetic resonance imaging (MRI) findings in Crohn's disease (CD) in correlation with pathological inflammatory score using surgical pathology analysis as a reference method., Methods: CD patients who were to undergo bowel resection surgery underwent MR enterography before surgery. The CD pathological inflammatory score of the surgical specimens was classified into three grades: mild or nonactive CD, moderately active CD, and severely active CD; fibrosis was also classified into three grades: mild, moderate, and severe. Mural and extramural MRI findings were correlated with pathological inflammatory and fibrosis grades., Results: Fifty-three consecutive patients were included retrospectively. The mean delay between MRI and surgery was 24 days (range 1-90, median 14). The CD pathological inflammatory score was graded as follows: grade 0 (11 patients, 21%), grade 1 (15 patients, 28%), and grade 2 (27 patients, 51%). MRI findings significantly associated with pathological inflammatory grading were wall thickness (P < 0.0001), degree of wall enhancement on delayed phase (P < 0.0001), pattern of enhancement on both parenchymatous (P = 0.02), and delayed phase, (P = 0.008), T2 relative hypersignal wall (P < 0.0001), blurred wall enhancement (P = 0.018), comb sign (P = 0.004), fistula (P < 0.0001), and abscess (P = 0.049). The inflammation score correlated with the fibrosis score (r = 0.63, P = 0.0001)., Conclusions: Our study identified MRI findings significantly associated with surgical pathological inflammation. These lesions are considered potentially reversible and may be efficiently treated medically. We also showed that fibrosis was closely and positively related to inflammation., (Copyright © 2010 Crohn's & Colitis Foundation of America, Inc.)

Background: Ulcerative Colitis (UC) and Crohn's Disease (CD) are two chronic Inflammatory Bowel Diseases (IBD) affecting the intestinal mucosa. Current understanding of IBD pathogenesis points out the interplay of genetic events and environmental cues in the dysregulated immune response. We hypothesized that dysregulated microRNA (miRNA) expression may contribute to IBD pathogenesis. miRNAs are small, non-coding RNAs which prevent protein synthesis through translational suppression or mRNAs degradation, and regulate several physiological processes., Methodology/findings: Expression of mature miRNAs was studied by Q-PCR in inactive colonic mucosa of patients with UC (8), CD (8) and expressed relative to that observed in healthy controls (10). Only miRNAs with highly altered expression (>5 or <0.2 -fold relative to control) were considered when Q-PCR data were analyzed. Two subsets of 14 (UC) and 23 (CD) miRNAs with highly altered expression (5.2->100 -fold and 0.05-0.19 -fold for over- and under- expression, respectively; 0.001

The homeostatic self-renewal of the colonic epithelium requires coordinated regulation of the canonical Wnt/beta-catenin and Notch signaling pathways to control proliferation and lineage commitment of multipotent stem cells. However, the molecular mechanisms by which the Wnt/beta-catenin and Notch1 pathways interplay in controlling cell proliferation and fate in the colon are poorly understood. Here we show that NADPH oxidase 1 (NOX1), a reactive oxygen species (ROS)-producing oxidase that is highly expressed in colonic epithelial cells, is a pivotal determinant of cell proliferation and fate that integrates Wnt/beta-catenin and Notch1 signals. NOX1-deficient mice reveal a massive conversion of progenitor cells into postmitotic goblet cells at the cost of colonocytes due to the concerted repression of phosphatidylinositol 3-kinase (PI3K)/AKT/Wnt/beta-catenin and Notch1 signaling. This conversion correlates with the following: (i) the redox-dependent activation of the dual phosphatase PTEN, causing the inactivation of the Wnt pathway effector beta-catenin, and (ii) the downregulation of Notch1 signaling that provokes derepression of mouse atonal homolog 1 (Math1) expression. We conclude that NOX1 controls the balance between goblet and absorptive cell types in the colon by coordinately modulating PI3K/AKT/Wnt/beta-catenin and Notch1 signaling. This finding provides the molecular basis for the role of NOX1 in cell proliferation and postmitotic differentiation.

Background: The mucosa-associated bacteria (MAB) are suspected of being involved in the pathogenesis of Crohn's disease. We analyzed and compared the MAB in noninflamed and inflamed ileal mucosa of Crohn's disease patients (n = 22)., Methods: Tissue samples from the inflamed ileal mucosa and from the adjacent noninflamed ileal mucosa were taken from surgical resection specimens. The MAB were investigated using fluorescence in situ hybridization with 7 group-specific probes and temporal temperature gradient gel electrophoresis (TTGE)., Results: Samples from both noninflamed and inflamed mucosa were obtained from 15 patients. The distribution of the bacterial populations was not different between noninflamed and inflamed mucosa. The Bacteroidetes phylum was dominant and accounted for 29% of MAB (0%-74%) in noninflamed tissues and 32% (0%-70%) in inflamed areas. The gamma Proteobacteria represented 12% (0%-70%) of MAB both in noninflamed and inflamed areas. The Clostridium coccoides group (Firmicutes phylum) represented 15% of MAB in noninflamed tissues versus 7% in inflamed areas. For most of the patients the similarity index between TTGE paired profiles was very high., Conclusion: The dominant MAB do not differ between noninflamed and inflamed ileal mucosa in Crohn's disease. This argues against a localized dysbiosis to explain the patchy distribution of mucosal lesions.