Gut virome-colonising Orthohepadnavirus genus is associated with ulcerative colitis pathogenesis and induces intestinal inflammation in vivo

OBJECTIVES

Ulcerative colitis (UC) is a chronic inflammatory disorder of unknown aetiology. Gut virome dysbiosis is fundamental in UC progression, although its role in the early phases of the disease is far from fully understood. Therefore, we sought to investigate the role of a virome-associated protein encoded by the Orthohepadnavirus genus, the hepatitis B virus X protein (HBx), in UC aetiopathogenesis.

DESIGN

HBx positivity of UC patient-derived blood and gut mucosa was assessed by RT-PCR and Sanger sequencing and correlated with clinical characteristics by multivariate analysis. Transcriptomics was performed on HBx-overexpressing endoscopic biopsies from healthy donors.C57BL/6 mice underwent intramucosal injections of liposome-conjugated HBx-encoding plasmids or the control, with or without antibiotic treatment. Multidimensional flow cytometry analysis was performed on colonic samples from HBx-treated and control animals. Transepithelial electrical resistance measurement, proliferation assay, chromatin immunoprecipitation assay with sequencing and RNA-sequencing were performed on in vitro models of the gut barrier. HBx-silencing experiments were performed in vitro and in vivo.

RESULTS

HBx was detected in about 45% of patients with UC and found to induce colonic inflammation in mice, while its silencing reverted the colitis phenotype in vivo. HBx acted as a transcriptional regulator in epithelial cells, provoking barrier leakage and altering both innate and adaptive mucosal immunity ex vivo and in vivo.

CONCLUSION

This study described HBx as a contributor to the UC pathogenesis and provides a new perspective on the virome as a target for tailored treatments.

Protective Effect and Mechanisms of Eckol on Chronic Ulcerative Colitis Induced by Dextran Sulfate Sodium in Mice

The use of functional foods and their bioactive components is receiving increasing attention as a complementary and alternative therapy for chronic ulcerative colitis (UC). This study explored the protective effect and mechanisms of Eckol, a seaweed-derived bioactive phlorotannin, on the dextran sodium sulfate (DSS)-induced chronic UC in mice. Eckol (0.5-1.0 mg/kg) reduced DSS-enhanced disease activity indexes, and alleviated the shortening of colon length and colonic tissue damage in chronic UC mice. The contents of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 were significantly decreased, and the level of anti-inflammatory IL-10 was enhanced in the serum and colonic tissues collected from Eckol-treated mice compared with the DSS controls. Eckol administration significantly reduced the number of apoptotic cells and the expression of cleaved Caspase-3, and increased the B-cell lymphoma-2 (Bcl-2)/B-cell lymphoma-2- associated X (Bax) ratio in DSS-challenged colons. There were more cluster of differentiation (CD)11c⁺ dendritic cells and CD8⁺ T cells, and less CD4⁺ T cells infiltrated to inflamed colonic tissues in the Eckol-treated groups. Expression of colonic Toll-like receptor 4 (TLR4), nuclear factor kappa-B (NF-κB) p65, phosphorylated-signal transducer and activator of transcription (pSTAT)3 was significantly down-regulated by Eckol compared with the DSS-challenged group. In conclusion, our data suggest that Eckol appeared to be a potential functional food ingredient for protection against chronic UC. The anti-colitis mechanisms of Eckol might be attributed to the down-regulation of the TLR4/NF-κB/STAT3 pathway, inhibition of inflammation and apoptosis, as well as its immunoregulatory activity.

Proposed pathway for therapeutic drug monitoring and dose escalation of vedolizumab

Vedolizumab is a gut-selective monoclonal antibody approved for the management of Crohn's disease and ulcerative colitis. The available data demonstrate a favourable response to dose escalation in patients with primary non-response or secondary loss of response to vedolizumab. While therapeutic drug monitoring has a proven clinical utility for tumour necrosis factor antagonists, the available guidance for therapeutic drug monitoring and dose escalation of vedolizumab is rather limited. The present review proposes a practical algorithm to use vedolizumab trough levels in the management of treatment failure. Therapeutic drug monitoring can differentiate underexposed patients from those with mechanistic failure. Underdosed patients can respond to dose escalation instead of unnecessarily switching to other treatment modalities. We also review the safety and potential cost-effectiveness of vedolizumab dose escalation, the role of antidrug antibodies and the possible applicability of this strategy to subcutaneous vedolizumab.

NAIL: an evolutionarily conserved lncRNA essential for licensing coordinated activation of p38 and NFκB in colitis

OBJECTIVE

NFκB is the key modulator in inflammatory disorders. However, the key regulators that activate, fine-tune or shut off NFκB activity in inflammatory conditions are poorly understood. In this study, we aim to investigate the roles that NFκB-specific long non-coding RNAs (lncRNAs) play in regulating inflammatory networks.

DESIGN

Using the first genetic-screen to identify NFκB-specific lncRNAs, we performed RNA-seq from the p65^-/- and Ikkβ^-/- mouse embryonic fibroblasts and report the identification of an evolutionary conserved lncRNA designated mNAIL (mice) or hNAIL (human). hNAIL is upregulated in human inflammatory disorders, including UC. We generated mNAIL^ΔNFκB mice, wherein deletion of two NFκB sites in the proximal promoter of mNAIL abolishes its induction, to study its function in colitis.

RESULTS

NAIL regulates inflammation via sequestering and inactivating Wip1, a known negative regulator of proinflammatory p38 kinase and NFκB subunit p65. Wip1 inactivation leads to coordinated activation of p38 and covalent modifications of NFκB, essential for its genome-wide occupancy on specific targets. NAIL enables an orchestrated response for p38 and NFκB coactivation that leads to differentiation of precursor cells into immature myeloid cells in bone marrow, recruitment of macrophages to inflamed area and expression of inflammatory genes in colitis.

CONCLUSION

NAIL directly regulates initiation and progression of colitis and its expression is highly correlated with NFκB activity which makes it a perfect candidate to serve as a biomarker and a therapeutic target for IBD and other inflammation-associated diseases.

Multicentre randomised controlled trial on virtual chromoendoscopy in the detection of neoplasia during colitis surveillance high-definition colonoscopy (the VIRTUOSO trial)

BACKGROUND

Longstanding colonic IBD increases the risk of developing colorectal cancer. The utility of chromoendoscopy with standard-definition white light technology has been established. However, the use of high-definition virtual chromoendoscopy (HDV) in colitis surveillance remains undefined.

OBJECTIVE

To compare the performance of HDV (i-scan OE mode 2) with high-definition white light (HDWL) for detection of neoplasia in patients with IBD undergoing surveillance colonoscopy. Additionally, we assessed the utility of protocol-guided quadrantic non-targeted biopsies.

DESIGN

A multioperator randomised controlled trial was carried out in two centres in the UK. Total of 188 patients (101 men, mean age 54) with longstanding ulcerative or Crohn's colitis were randomised, prior to starting the surveillance colonoscopy, to using either HDV (n=94) or HDWL (n=94) on withdrawal. Targeted and quadrantic non-targeted biopsies were taken in both arms per-randomisation protocol. The primary outcome was the difference in neoplasia detection rate (NDR) between HDV and HDWL.

RESULTS

There was no significant difference between HDWL and HDV for neoplasia detection. The NDR was not significantly different for HDWL (24.2%) and HDV (14.9%) (p=0.14). All intraepithelial neoplasia (IEN) detected contained low-grade dysplasia only. A total of 6751 non-targeted biopsies detected one IEN only. The withdrawal time was similar in both arms of the study; median of 24 min (HDWL) versus 25.5 min (HDV).

CONCLUSION

HDV and HDWL did not differ significantly in the detection of neoplasia. Almost all neoplasia were detected on targeted biopsy or resection. Quadrantic non-targeted biopsies have negligible additional gain.

TRIAL REGISTRATION NUMBER

Clinical Trial.gov ID NCT02822352.

Asian Organization for Crohn's and Colitis and Asia Pacific Association of Gastroenterology practice recommendations for medical management and monitoring of inflammatory bowel disease in Asia

Inflammatory bowel disease (IBD) has increased in incidence and prevalence in Asian countries since the end of the 20th century. Moreover, differences in the cause, phenotypes, and natural history of IBD between the East and West have been recognized. Therefore, the Asian Organization for Crohn's and Colitis and the Asia Pacific Association of Gastroenterology have established recommendations on medical management of IBD in Asia. Initially, the committee members drafted 40 recommendations, which were then assessed according to Grading of Recommendations Assessment, Development and Evaluation. Eight statements were rejected as this indicated that consensus had not been reached. The recommendations encompass pretreatment evaluation; medical management of active IBD; medical management of IBD in remission; management of IBD during the periconception period and pregnancy; surveillance strategies for colitis-associated cancer; monitoring side effects of thiopurines and methotrexate; and infections in IBD.

Protein diets with the role of immune and gut microbial regulation alleviate DSS-induced chronic ulcerative colitis

The association between diet and inflammatory bowel disease (IBD) has been confirmed. However, the role of protein consumption in IBD remains controversial. This research aimed to explore the effects of milk-based protein (MBP), potato protein (PP), and mixed protein (MP) on the recovery of mice with dextran sulfate sodium (DSS)-induced ulcerative colitis (UC). MP alleviated UC symptoms through reducing colon shortening and tissue damage, decreasing neutrophil infiltration, maintaining the mucous layer integrity, and suppressing the expression of TNF-α, IL-17A, IL-6, and IL-1β. MBP and PP decreased the colon shortening and IL-1β levels but PP increased the MUC2 expression. Additionally, the gut microbial structure and composition were altered after different proteins supplement. Compared to DSS-treated mice, MP-treated mice showed that increased abundances in Coprococcus and Bifidobacterium and decreased abundances in Sutterella, Lactobacillus, and Akkermansia. MBP increased the proportion of Bifidobacterium and reduced Sutterella, but PP increased Ruminococcus and Bifidobacterium and decreased Adlercreutzia. Correspondence analysis of gut microbial composition to determine the effects of protein diets on immune response and pathological characteristics also verified the interaction between gut microbiota and alleviation of colitis. These results provide a theoretical basis for the selection of raw materials for clinical enteral nutrition preparations and potential use for potato protein wastes.

Microbiota fermentation-NLRP3 axis shapes the impact of dietary fibres on intestinal inflammation

OBJECTIVE

Diets rich in fermentable fibres provide an array of health benefits; however, many patients with IBD report poor tolerance to fermentable fibre-rich foods. Intervention studies with dietary fibres in murine models of colonic inflammation have yielded conflicting results on whether fibres ameliorate or exacerbate IBD. Herein, we examined how replacing the insoluble fibre, cellulose, with the fermentable fibres, inulin or pectin, impacted murine colitis resulting from immune dysregulation via inhibition of interleukin (IL)-10 signalling and/or innate immune deficiency (Tlr5KO).

DESIGN

Mice were fed with diet containing either cellulose, inulin or pectin and subjected to weekly injections of an IL-10 receptor (αIL-10R) neutralising antibody. Colitis development was examined by serological, biochemical, histological and immunological parameters.

RESULTS

Inulin potentiated the severity of αIL10R-induced colitis, while pectin ameliorated the disease. Such exacerbation of colitis following inulin feeding was associated with enrichment of butyrate-producing bacteria and elevated levels of caecal butyrate. Blockade of butyrate production by either metronidazole or hops β-acids ameliorated colitis severity in inulin-fed mice, whereas augmenting caecal butyrate via tributyrin increased colitis severity in cellulose containing diet-fed mice. Elevated butyrate levels were associated with increased IL-1β activity, while inhibition of the NOD-like receptor protein 3 by genetic, pharmacologic or dietary means markedly reduced colitis.

CONCLUSION

These results not only support the notion that fermentable fibres have the potential to ameliorate colitis but also caution that, in some contexts, prebiotic fibres can lead to gut dysbiosis and surfeit colonic butyrate that might exacerbate IBD.

Effect of a Milk-Based Fruit Beverage Enriched with Plant Sterols and/or Galactooligosaccharides in a Murine Chronic Colitis Model

The potential anti-inflammatory effect of plant sterols (PS) enriched milk-based fruit beverages (PS, 1 g/100 mL) (MfB) with/without galactooligosaccharides (GOS, 2 g/100 mL) (MfB-G) in an experimental mice model of chronic ulcerative colitis was evaluated. Beverages were orally administered to mice every day by gavage to achieve PS and GOS doses of 35 and 90 mg/kg, respectively, and experimental colitis was induced by giving mice drinking water ad libitum containing 2% (w/v) dextran sulphate sodium (DSS) for 7 days, alternating with periods without DSS up to the end of the study (56 days). MfB beverage showed significant reduction of symptoms associated to ulcerative colitis and improved the colon shortening and mucosal colonic damage, but it was not able to reduce the increase of myeloperoxidase levels produced by DSS. MfB-G showed higher incidence of bloody feces and loss of stool consistency than MfB, as well as high levels of immune cells infiltration in colon tissue and myeloperoxidase. Therefore, PS-enriched milk-based fruit beverage could be an interesting healthy food to extend the remission periods of the diseases and the need to evaluate, in a pre-clinical model, the anti-inflammatory effect of the combination of bioactive compounds in the context of a whole food matrix.

Impact of thiopurines on the natural history and surgical outcome of ulcerative colitis: a cohort study

OBJECTIVE

Thiopurines are used as maintenance therapy in ulcerative colitis (UC), but whether these drugs influence the natural history of the disease is unknown. We aimed to assess the effect of thiopurines in terms of colectomy, hospital admission, progression in disease extent and anti-tumour necrosis factor (TNF) therapy within 10 years from initiation.

DESIGN

Patients diagnosed with UC within the Örebro University Hospital catchment area, during 1963-2010, who initiated thiopurines (n=253) were included. To overcome the risk of confounding by indication, we compared patients who stopped treatment within 12 months because of an adverse reaction (n=76) with patients who continued therapy or discontinued due to other reasons (n=177) and assessed long-term outcomes using Cox regression with adjustment for potential confounding factors.

RESULTS

The cumulative probability of colectomy within 10 years was 19.5% in tolerant patients compared with 29.0% in intolerant (adjusted HR 0.49; 95% CI 0.21 to 0.73). The probability of hospital admission was 34.0% in tolerant versus 56.2% in intolerant patients (adjusted HR 0.36; 95% CI 0.23 to 0.56). The risk for progression in disease extent was 20.4% in tolerant patients compared with 48.8% in intolerant (adjusted HR 0.47; 95% CI 0.21 to 1.06). Within 10 years, 16.1% of tolerant and 27.5% of intolerant patients received anti-TNF therapy (adjusted HR 0.49; 95% CI 0.26 to 0.92).

CONCLUSION

Based on the novel approach of comparing patients tolerant and intolerant to thiopurines, we reveal that thiopurines have a profound beneficial impact of the natural history and long-term colectomy rates of UC.

Adherent-invasive Escherichia coli in inflammatory bowel disease

Intestinal microbiome dysbiosis has been consistently described in patients with IBD. In the last decades, Escherichia coli, and the adherent-invasive E coli (AIEC) pathotype in particular, has been implicated in the pathogenesis of IBD. Since the discovery of AIEC, two decades ago, progress has been made in unravelling these bacteria characteristics and its interaction with the gut immune system. The mechanisms of adhesion of AIEC to intestinal epithelial cells (via FimH and cell adhesion molecule 6) and its ability to escape autophagy when inside macrophages are reviewed here. We also explore the existing data on the prevalence of AIEC in patients with Crohn's disease and UC, and the association between the presence of AIEC and disease location, activity and postoperative recurrence. Finally, we highlight potential therapeutic strategies targeting AIEC colonisation of gut mucosa, including the use of phage therapy, bacteriocins and antiadhesive molecules. These strategies may open new avenues for the prevention and treatment of IBD in the future.

Seasonal clustering in inflammatory bowel disease: a single centre experience

BACKGROUNDS AND AIMS

External stimuli are considered as possible triggers for the onset of inflammatory bowel disease (IBD), and particularly chronic ulcerative colitis (CUC) in genetically susceptible individuals. Our aims were to investigate monthly clustering-patterns in the onset of symptoms and diagnosis of IBD, as well as health seeking behavior in those individuals.

MATERIALS AND METHODS

Two hundred and eighty-two consecutive patients with IBD were included. Onset of symptoms (month) and delay to diagnosis were analyzed. Kruskal-Wallis and Roger's test were used to analyze for statistical patterns in seasonal clustering.

RESULTS

There were 181 males and 101 females with IBD; mean age: 40 ± 14.7 years (median: 38, range: 14-79 years). The peak number of IBD cases was seen in winter/early spring, with the lowest numbers in autumn, which reached statistical significance in the CUC group (p: 0.029). Seasonal changes were not significantly affected by gender. The time delay to diagnosis from symptom onset was 3.0 ± 2.3 months in males (median: 2, range: 0-12 months) vs 3.2 ± 3.2 months (median: 2, range: 0-18 months) in females (not statistically significant).

CONCLUSION

Our results show a seasonal relation in IBD cases, particularly in CUC, which may suggest external stimuli acting as a precipitant to IBD in susceptible individuals. There was a delay between symptom onset and CUC diagnosis, which was not felt to be clinically significant.

[Tuberculoid leprosy revealed by active ulcerative colitis: a case report]

Leprosy is endemic in Senegal. In 2011, there were 73 new cases reported in Dakar. The circumstances of discovery are often dermatologic or neurologic. Few case reports describe an association with chronic inflammatory colitis, probably fortuitous. We report the case of a 30-year-old woman who had a tuberculoid leprosy revealed by active ulcerative colitis. Treatment according to the WHO protocol of leprosy, combined with corticosteroids and then methotrexate, resulted in healing of the leprosy and remission of the colitis.

Antioxidant properties of mesalamine in colitis inhibit phosphoinositide 3-kinase signaling in progenitor cells

BACKGROUND

Mesalamine, 5-aminosalicylic acid (5-ASA), is a potent antioxidant and is known to enhance peroxisome proliferator-activated receptor γ activity in the intestine. Our previous studies suggested reduced Phosphoinositide 3-Kinase (PI3K)/β-catenin signaling as a mechanism for 5-ASA chemoprevention in chronic ulcerative colitis (CUC). We now hypothesize that 5-ASA mediates changes in intestinal epithelial cell (IEC) reactive oxygen species during colitis to affect phosphatase and tensin homolog (PTEN), PI3K, and β-catenin signaling.

METHODS

Here, we examined effects of 5-ASA on oxidant-induced cell signaling pathways in HT-29 cells, IECs from mice, and biopsy tissue from control and CUC patients. Samples were selected to control for inflammation between untreated and 5-ASA-treated CUC patients.

RESULTS

Direct evaluation of IEC in H2O2-stimulated whole colonic crypts indicated that 5-ASA reduces reactive oxygen species levels in lower crypt IECs where long-lived progenitor cells reside. Analysis of biopsies from patient samples revealed that 5-ASA increases expression of the antioxidant catalase in CUC patients. Also, 5-ASA increased nuclear peroxisome proliferator-activated receptor γ protein and target gene expression. Data showed 5-ASA-induced peroxisome proliferator-activated receptor γ DNA binding to the PTEN promoter (chromatin immunoprecipitation) and reduced both phosphorylated and oxidized (inactive) PTEN protein levels. Analysis of patient samples revealed 5-ASA that also reduced levels of active phosphorylated Akt in inflamed colitis tissue. Reduced PI3K/Akt signaling and expression of β-catenin target genes in 5-ASA-treated CUC patients additionally suggests enhanced PTEN activity as well.

CONCLUSIONS

Therefore, 5-ASA reduces CUC-induced reactive oxygen species in colonic progenitor cells and enhances PTEN activity, thus attenuating PI3K/Akt signaling. These data suggest that the antioxidant properties of 5-ASA may be the predominant mechanism for 5-ASA chemoprevention.

Venous thromboembolism after surgery for inflammatory bowel disease: are there modifiable risk factors? Data from ACS NSQIP

BACKGROUND

Although it is commonly reported that IBD patients are at increased risk for venous thromboembolic events, little real-world data exist regarding their postoperative incidence and related outcomes in everyday practice.

OBJECTIVE

We aimed to identify the rate of venous thromboembolism and modifiable risk factors within a large cohort of surgical IBD patients.

DESIGN

We performed a retrospective review of IBD patients who underwent colorectal procedures.

PATIENTS

Patient data were obtained from the American College of Surgeons National Surgical Quality Improvement Program 2004 to 2010 Participant Use Data Files.

MAIN OUTCOME MEASURES

The primary outcomes measured were short-term (30-day) postoperative venous thromboembolism (deep vein thrombosis and pulmonary embolism). Clinical variables were analyzed by univariate and multivariate analyses to identify modifiable risk factors for these events.

RESULTS

A total of 10,431 operations were for Crohn's disease (52.1%) or ulcerative colitis (47.9%), and 242 (2.3%) venous thromboembolic events occurred (178 deep vein thromboses, 46 pulmonary embolisms, 18 both) for a combined rate of 1.4% in Crohn's disease and 3.3% in ulcerative colitis. Deep vein thrombosis and pulmonary embolism each occurred at a mean of 10.8 days postoperatively (range for each, 0-30 days). A multivariate model found that bleeding disorder, steroid use, anesthesia time, emergency surgery, hematocrit <37%,malnutrition, and functional status were potentially modifiable risk factors that remained associated (p < 0.05) with venous thromboembolism on regression analysis. Patients with thromboembolism had longer length of stay (18.8 vs 8.9 days), more complications (41% vs 18%), and a higher risk of death (4% vs 0.9%).

LIMITATIONS

This study was limited by its retrospective design and its limited generalizability to nonparticipating hospitals.

CONCLUSIONS

Inflammatory bowel disease patients are at increased risk for postoperative venous thromboembolism. Reducing preoperative anemia, steroid use, malnutrition, and anesthesia time may also reduce venous thromboembolism in this at-risk population. Risk-reducing, preventative strategies are needed in this at-risk population.

Developing an instrument to assess the endoscopic severity of ulcerative colitis: the Ulcerative Colitis Endoscopic Index of Severity (UCEIS)

BACKGROUND

Variability in endoscopic assessment necessitates rigorous investigation of descriptors for scoring severity of ulcerative colitis (UC).

OBJECTIVE

To evaluate variation in the overall endoscopic assessment of severity, the intra- and interindividual variation of descriptive terms and to create an Ulcerative Colitis Endoscopic Index of Severity which could be validated.

DESIGN

A two-phase study used a library of 670 video sigmoidoscopies from patients with Mayo Clinic scores 0-11, supplemented by 10 videos from five people without UC and five hospitalised patients with acute severe UC. In phase 1, each of 10 investigators viewed 16/24 videos to assess agreement on the Baron score with a central reader and agreed definitions of 10 endoscopic descriptors. In phase 2, each of 30 different investigators rated 25/60 different videos for the descriptors and assessed overall severity on a 0-100 visual analogue scale. κ Statistics tested inter- and intraobserver variability for each descriptor. A general linear mixed regression model based on logit link and β distribution of variance was used to predict overall endoscopic severity from descriptors.

RESULTS

There was 76% agreement for 'severe', but 27% agreement for 'normal' appearances between phase I investigators and the central reader. In phase 2, weighted κ values ranged from 0.34 to 0.65 and 0.30 to 0.45 within and between observers for the 10 descriptors. The final model incorporated vascular pattern, (normal/patchy/complete obliteration) bleeding (none/mucosal/luminal mild/luminal moderate or severe), erosions and ulcers (none/erosions/superficial/deep), each with precise definitions, which explained 90% of the variance (pR(2), Akaike Information Criterion) in the overall assessment of endoscopic severity, predictions varying from 4 to 93 on a 100-point scale (from normal to worst endoscopic severity).

CONCLUSION

The Ulcerative Colitis Endoscopic Index of Severity accurately predicts overall assessment of endoscopic severity of UC. Validity and responsiveness need further testing before it can be applied as an outcome measure in clinical trials or clinical practice.

PSC-IBD: a unique form of inflammatory bowel disease associated with primary sclerosing cholangitis

BACKGROUND

Inflammatory bowel disease associated with primary sclerosing cholangitis (PSC-IBD) may have a high prevalence of rectal sparing, backwash ileitis, and colorectal neoplasia.

AIMS

To describe the clinical features and outcomes of PSC-IBD and compare these to a group of chronic ulcerative colitis (CUC) patients.

METHODS

The medical records of all patients with PSC-IBD evaluated at the Mayo Clinic Rochester between 1987 and 1992 were abstracted for information on endoscopic and histological features, colorectal neoplasia, surgery, and other clinical outcomes. Patients referred for colorectal neoplasia and those who did not undergo colonoscopy with biopsies were excluded. A control group of CUC patients matched for sex, duration of IBD at first clinic visit, and calendar year of first clinic visit was identified, and similar information was abstracted.

RESULTS

Seventy one PSC-IBD patients and 142 CUC patients without PSC were identified. Rectal sparing and backwash ileitis were more common in the PSC-IBD group (52% and 51%, respectively) than in controls (6% and 7%, respectively). Overall, colorectal neoplasia developed in 18 cases and 15 controls, including 11 cancers (seven cases and four controls). An increased risk of colorectal neoplasia or death was not detected in a matched analysis. Although the cumulative incidence of colorectal neoplasia was higher in cases (33%) than in controls (13%) at five years, this was of borderline statistical significance (p=0.054, unmatched log rank test). Overall survival from first clinic visit was significantly worse among cases (79% v 97%) at five years (p<0.001, unmatched log rank test).

CONCLUSION

PSC-IBD is frequently characterised by rectal sparing and backwash ileitis. Colorectal neoplasia develops in a substantial fraction and overall survival is worse. PSC-IBD may represent a distinct IBD phenotype.