Harald Peeters

Microscopic gut inflammation in axial spondyloarthritis: a multiparametric predictive model

Objective To assess the rates and explore predictors of microscopic gut inflammation in a cohort of patients with axial and peripheral spondyloarthritis (SpA). Methods Ileocolonoscopy was performed in 65 patients with axial and peripheral SpA from the Gent Inflammatory Arthritis and spoNdylitis cohorT. Histopathological analysis and scoring were performed by an experienced pathologist. Results Overall, 46.2% of the patients with SpA showed microscopic gut inflammation. In axial SpA, the following parameters were independently associated with gut involvement: male sex (OR=8.9, p=0.035); high disease activity measured by the Bath Ankylosing Spondylitis Disease Activity Index (OR=2.05, p=0.032); restricted spinal mobility measured by the Bath Ankylosing Spondylitis Metrology Index (OR=1.94, p=0.009); and younger age (OR=0.85, p=0.013). No clear association was found for human leucocyte antigen-B27 status, presence of peripheral arthritis, enthesitis, uveitis, psoriasis, intake of non-steroidal anti-inflammatory drugs and family history of SpA. The prevalence of gut inflammation in non-radiographic axial SpA and ankylosing spondylitis was comparable. Conclusions The prevalence of microscopic gut inflammation in SpA remains unaltered over time. Younger age (shorter symptom duration), progressive disease, male sex and higher disease activity are independently associated with microscopic gut inflammation in axial SpA.

Adalimumab dose escalation and dose de-escalation success rate and predictors in a large national cohort of Crohn's patients

BACKGROUND AND AIMS Adalimumab is efficacious in inducing and maintaining remission in Crohns disease but dose escalation is needed in 30-40% after 1 year. Attempts for dose de-escalation have not been studied. This study aimed to assess the need for, predictors, and outcome of dose escalation and de-escalation in a large cohort of adalimumab treated Crohns patients. METHODS All consecutive patients treated with open label adalimumab for active Crohns disease from the participating centres were included in this cohort study. A detailed retrospective chart review was performed to look for possible factors predicting outcome. RESULTS Eighty four percent of 720 patients had a primary response and were followed up for a median of 14 months. Thirty four percent needed escalation after a median of 7 months (0-55 months). Multivariate predictors for dose escalation were the following: prior anti-TNF use (p<0.0001), no concomitant azathioprine or <3 m (p<0.02) and abnormal CRP at start (p<0.05). Dose escalation re-induced response for at least 6 months in 67%. Only abnormal CRP at start correlated with failure of dose escalation (p=0.02). Dose de-escalation was attempted in 54% and was successful in 63%. After a median follow-up of 14 m adalimumab was discontinued in 29% of patients. CONCLUSION In this study real life nationwide cohort of Crohns patients treated with adalimumab dose escalation was needed in 34% and was successful in 67%. Dose de-escalation was attempted in 54% and was successful in 63%. Overall 71% of patients maintained long term response on adalimumab.

Hydroxylase Inhibition Abrogates TNF-α–Induced Intestinal Epithelial Damage by Hypoxia-Inducible Factor-1–Dependent Repression of FADD

Hydroxylase inhibitors stabilize hypoxia-inducible factor-1 (HIF-1), which has barrier-protective activity in the gut. Because the inflammatory cytokine TNF-α contributes to inflammatory bowel disease in part by compromising intestinal epithelial barrier integrity, hydroxylase inhibition may have beneficial effects in TNF-α–induced intestinal epithelial damage. The hydroxylase inhibitor dimethyloxalylglycin (DMOG) was tested in a murine model of TNF-α–driven chronic terminal ileitis. DMOG-treated mice experienced clinical benefit and showed clear attenuation of chronic intestinal inflammation compared with that of vehicle-treated littermates. Additional in vivo and in vitro experiments revealed that DMOG rapidly restored terminal ileal barrier function, at least in part through prevention of TNF-α–induced intestinal epithelial cell apoptosis. Subsequent transcriptional studies indicated that DMOG repressed Fas-associated death domain protein (FADD), a critical adaptor molecule in TNFR-1-mediated apoptosis, in an HIF-1α–dependent manner. Loss of this FADD repression by HIF-1α-targeting small interfering RNA significantly diminished the antiapoptotic action of DMOG. Additional molecular studies led to the discovery of a previously unappreciated HIF-1 binding site in the FADD promoter, which controls repression of FADD during hypoxia. As such, the results reported in this study allowed the identification of an innate mechanism that protects intestinal epithelial cells during (inflammatory) hypoxia, by direct modulation of death receptor signaling. Hydroxylase inhibition could represent a promising alternative treatment strategy for hypoxic inflammatory diseases, including inflammatory bowel disease.

Clinical and genetic factors associated with sacroiliitis in Crohn's disease

Background and Aim:  Radiographic sacroiliitis (SI), often asymptomatic, is considered the most frequent extra‐intestinal manifestation (EIM) of Crohns disease (CD). Data on the association of SI with other clinical features of CD are limited. Association of SI with CARD15 polymorphisms has recently been suggested. In a multicenter study, we investigated the association of SI in CD patients with clinical phenotypes, other EIM and CARD15 polymorphisms.

CARD15 variants determine a disturbed early response of monocytes to adherent-invasive Escherichia coli strain LF82 in Crohn's disease.

Caspase activation and recruitment domain 15 (CARD15) and Toll‐like receptor 4 (TLR4) are respectively intracellular and membrane‐bound receptors for bacterial cell wall components [respectively muramyl dipeptide (MDP) and lipopolysaccharide (LPS)]. Polymorphisms in CARD15 and TLR4 have been linked with Crohns disease (CD). Adherent‐invasive Escherichia coli (AIEC) strains with particular adhesion and invasion characteristics have been specifically associated with CD ileal mucosa. The aim of this study was to investigate the functional impact of these polymorphisms on monocytes in patients with CD, in response to MDP, LPS and AIEC strain LF82. Monocytes were isolated from 40 patients with CD using magnetic cell sorting, stimulated with LPS or MDP or infected with AIEC. IL‐1β, IL‐6, IL‐8, IL‐10, IL‐12 and tumour necrosis factor alpha induction was assessed using quantitative real time–polymerase chain reaction, Cytometric Bead Array and ELISA. Bacterial intracellular survival and replication was assessed using a gentamicin protection assay. Results were linked with the presence of CARD15 and TLR4 polymorphisms. Monocytes of patients with CARD15 polymorphisms showed an early reduced cytokine response (IL‐1β, IL‐6 and IL‐10) to infection with AIEC, which was restored after 20 h. A gene–dose effect was seen, comparing wild‐types, heterozygotes and homozygotes. We found no differences in intracellular survival and replication of AIEC. Heterozygous carriage of TLR4 polymorphisms did not influence monocyte response. In conclusion, patients with CD carrying CARD15 polymorphisms show a disturbed early inflammatory monocyte response after infection with AIEC strain LF82. For the first time, a functional defect was detected in single heterozygous carriers. These findings reflect the potential role of a genetically altered host response to disease‐related bacteria in the pathogenesis of CD.

Limitations of extensive TPMT genotyping in the management of azathioprine-induced myelosuppression in IBD patients

BACKGROUND AND AIMS TPMT deficiency is associated with azathioprine (AZA)-induced myelosuppression (MS). However, in one previous study, only about ¼ of MS episodes in Crohns Disease patients under AZA can be attributed to TPMT deficiency. Recently, new TPMT mutations have been described and our aim is to investigate their clinical relevance before and after a first MS episode on thiopurine therapy. METHODS Clinical data from 61 IBD patients having developed MS during AZA therapy were collected. Sequencing analysis was carried out on TPMT cDNA for the presence of all currently known mutations. RESULTS Only TPMT *2, *3A and *3C mutations were found in this cohort. TPMT mutations were observed in 15 out of 61 patients (25%). Four out of 15 were homozygous for a TPMT mutation (low methylator, LM genotype) and 11 were heterozygous (intermediate methylator, IM genotype). Median delays of MS onset were 2, 2.75 and 6months in the LM, IM and HM (high methylator, wild type TPMT) groups, respectively. After the first MS episode, 36 patients resumed thiopurine treatment of which 13 experienced a second MS episode. This second episode was also rarely associated with TPMT mutations. CONCLUSIONS One quarter of MS episodes during AZA were associated with TPMT deficient genotype. After a first leucopenia episode, thiopurine therapy may be resumed in a majority of patients independently of their TPMT genotype.

Altered gut transcriptome in spondyloarthropathy

Background: Intestinal inflammation is a common feature of spondyloarthropathy (SpA) and Crohn’s disease. Inflammation is manifested clinically in Crohn’s disease and subclinically in SpA. However, a fraction of patients with SpA develops overt Crohn’s disease. Aims: To investigate whether subclinical gut lesions in patients with SpA are associated with transcriptome changes comparable to those seen in Crohn’s disease and to examine global gene expression in non-inflamed colon biopsy specimens and screen patients for differentially expressed genes. Methods: Macroarray analysis was used as an initial genomewide screen for selecting a comprehensive set of genes relevant to Crohn’s disease and SpA. This led to the identification of 2625 expressed sequence tags that are differentially expressed in the colon of patients with Crohn’s disease or SpA. These clones, with appropriate controls (6779 in total), were used to construct a glass-based microarray, which was then used to analyse colon biopsy specimens from 15 patients with SpA, 11 patients with Crohn’s disease and 10 controls. Results: 95 genes were identified as differentially expressed in patients with SpA having a history of subclinical chronic gut inflammation and also in patients with Crohn’s disease. Principal component analysis of this filtered set of genes successfully distinguished colon biopsy specimens from the three groups studied. Patients with SpA having subclinical chronic gut inflammation cluster together and are more related to those with Crohn’s disease. Conclusion: The transcriptome in the intestine of patients with SpA differs from that of controls. Moreover, these gene changes are comparable to those seen in patients with Crohn’s disease, confirming initial clinical observations. On the basis of these findings, new (genetic) markers for detection of early Crohn’s disease in patients with SpA can be considered.

Profile of pediatric Crohn's disease in Belgium

AIM A Belgian registry for pediatric Crohns disease, BELCRO, was created. This first report aims at describing disease presentation and phenotype and determining associations between variables at diagnosis and registration in the database. METHODS Through a collaborative network, children with previously established Crohns disease and newly diagnosed children and adolescents (under 18 y of age) were recruited over a 2 year period. Data were collected by 23 centers and entered in a database. Statistical association tests analyzed relationships between variables of interest at diagnosis. RESULTS Two hundred fifty-five patients were included. Median age at diagnosis was 12.5 y (range: 1.6-18 y); median duration of symptoms prior to diagnosis was 3 m (range: 1-12 m). Neonatal history and previous medical history did not influence disease onset nor disease behavior. Fifty three % of these patients presented with a BMI z-score < -1. CRP was an independent predictor of disease severity. Steroids were widely used as initial treatment in moderate to severe and extensive disease. Over time, immunomodulators and biological were prescribed more frequently, reflecting a lower prescription rate for steroids and 5-ASA. A positive family history was the sole significant determinant for earlier use of immunosuppression. CONCLUSION In Belgium, the median age of children presenting with Crohns disease is 12.5 y. Faltering growth, extensive disease and upper GI involvement are frequent. CRP is an independent predictive factor of disease activity. A positive family history appears to be the main determinant for initial treatment choice.

561 Successive Treatment with Cyclosporine and Infliximab in Severe Ulcerative Colitis (UC)

Introduction: Higher 6-tioguanine nucleotide (6TGN) concentrations have been related to higher probabilities of achieving clinical remission on thiopurinic therapy, but that has been hardly applied to clinical practice. Aims: To establish the utility of systematic determination of 6TGN as a marker or predictor of AZA/mercaptopurine (MP) efficacy in IBD patients. Methods: Prospective, multicenter study. Serum 6TGN and 6-methylmercaptopurine ribonucleotides (6MMPR) levels of patients starting AZA/MP for steroid dependence or resistance were periodically monitored during steroid tapering and, after withdrawal, until a new activity flare (persistence of steroid resistance or dependence), or for 6 months in those showing maintenance of clinical response. Thiopurine methyl-transferase (TPMT) activity above 5 U/ml was required. Results: 153 patients were included, and 140 finished the study. Mean age was 36 years (range 16-77), 50% were males, and 72% had Crohns disease. Mean 6TGN levels (and the ratios 6TGN/6MMPR, 6TGN/TPMT) obtained at basal, 2 weeks, and 1, 2, 4 and 6 months after steroid withdrawal were not significantly different between patients that were or were not in clinical remission at each visit. The area under the ROC curve (AUC) evaluating the accuracy of 6TGN levels for the diagnosis of clinical response for each monitoring point was less than 0.7. No cut-off point with useful sensitivity/specificity values was found, including 230 or 260 pmol/8 x 108 (that are commonly proposed in the literature). The AUC assessing the accuracy of the 6TGN determination at 2 weeks, 1, 2 or 4 months after starting AZA/MP to predict the response by the end of the follow-up was also less than 0.7. Once again, no useful cut-off point was found. Thiopurinic-related toxicity was detected in 9 cases (6.4%): No cases of hepatotoxicity were found, and only 3 cases of myelotoxicity were reported. No differences in 6TGN levels were found in patients suffering AZA-related toxicity. Specifically, 6TGN levels could not be related to the risk of developing myelotoxicity. Conclusions: Systematic quantification of thiopurinic metabolites (6TGN/ 6MMPR) in IBD patients receiving AZA/MP with the aim of predicting or assessing treatment response or safety cannot be recommended.

1052 Daily Mesalamine Fails to Prevent Recurrent Diverticulitis in a Large Placebo Controlled Multicenter Trial

3 focus groups of 45 SUDD patients and an expert panel of five gastroenterologists and surgeons. We developed the DV-QOL items based on our literature search and input from focus groups and experts, and obtained feedback from patients about those items in cognitive debriefing interviews. We administered the items to a cohort of SUDD patients with persistent symptoms following a confirmed diverticulitis event. We created scales based on factor analysis and evaluated the scales for reliability and validity. Results: Concept elicitation revealed a range of illness experiences attributed to SUDD. Coding of 20,490 transcribed words yielded 52 codes arranged in a network with 4 first-order condition-related concepts: (1) physical symptoms (e.g., pain, bloating); (2) behaviors (e.g., dietary, physical, and social restrictions); (3) cognitions and concerns (e.g., lack of control, feeling something wrong); and (4) impact and consequences (e.g., frustration, anxiety). Initially, we developed 46 items that reflected these four concepts. Using data from a cross-sectional validation sample of 197 patients, we reduced the DV-QOL to a 24-item instrument. The final instrument demonstrated strong internal consistency (Cronbachs Alpha = 0.95) and a reliable fourfactor solution (Tucker and Lewis Reliability Coefficient = 0.90). In our validation sample, the DV-QOL significantly discriminated between patients with recent (i.e., within last month) versus distant diverticulitis events (effect size of DV-QOL score difference = 0.66), and correlated strongly with both the Short-Form 36 subscales (mean correlation = -0.49) and hospital anxiety and depression (HAD) scores (mean correlation = 0.50). Conclusions: Patients with diverticular disease attribute a wide range of negative psychological, social, and physical symptoms to their condition, even outside of acute attacks. The DV-QOL captures these symptoms in a valid and reliable manner.