bwge2017

Authors
S. VAN STEENBERGEN (1), S. BIAN (2), V. BALLET (1), S. VERMEIRE (1), G. VAN ASSCHE (1), A. GILS (2), M. FERRANTE (3) / [1] University Hospitals Leuven, KU Leuven, Leuven, Belgium, Department of Gastroenterology and Hepatology, [2] KU Leuven, Leuven, Belgium, Laboratory for Therapeutic and Diagnostic Antibodies, [3] University Hospitals Leuven, KU Leuven, Leuven, Belgium, Department of Gastroenterology

Introduction
Although dose escalation is widely used to optimize anti-TNF therapy in case of relapse, less is known about possibilities to de-escalate therapy in patients with Crohn’s disease (CD) who are in clinical remission. Dose de-escalation may not only have beneficial economic consequences, it may possibly also decrease adverse events.

Aim

In this retrospective study, the outcome of dose de-escalation to adalimumab (ADM) 40 mg every three weeks (ETW) in patients with CD was studied.

Methods
Out of 703 patients treated with ADM for moderate-to-severe CD in a tertiary referral center, we selected all patients who had received maintenance therapy with ADM 40 mg ETW with serum levels (SL) available before and after dose de-escalation. A sex- and age-matched control group consisted of patients continuing ADM 40mg EOW. ADM SL were measured using RIDASCREEN® monitoring kit (R-biopharm AG). In addition, patient reported outcome (PRO2), C-reactive protein (CRP) and serum albumin were collected. Other baseline variables included disease behavior, disease location, smoking behavior, concomitant therapy, bodyweight, and body mass index. ROC curve analyses were performed to define cut off values for continuous variables. Mann-Whitney U, Wilcoxon Signed Rank test, and Cox regression were performed using SPSS 23.0

Results
We identified 40 patients (11 male, median age 37 years) who dose de-escalated to ADM 40 mg ETW for ADM-related AE (n=1), ADM SL >7µg/mL (n=8), or both (n=31). Most frequently reported AE were skin manifestations (47%), arthralgia (22%) and frequent infectious episodes (22%). Compared to the control population, ADM SL dropped significantly within four months, but without associated clinical or biochemical changes. During a median follow-up of 24 months, 65% of patients maintained clinical response, but 35% needed dose escalation back to ADM 40mg EOW because of clinical relapse (n=8), ADM SL dropping to <4µg/mL (n=2), or both (n=4). CRP <3.5mg/L at dose de-escalation was independently associated with dose escalation free survival [Odds ratio 6.28 (95%CI 1.83-21.59), p=0.004]. We could not define a minimal ADM SL to consider or maintain dose de-escalation. In 53% of 32 patients dose de-escalation was associated with a complete disappearance of AE and this after a median of 4 months (8/15 skin manifestation, 3/7 arthralgia, 5/7 frequent infectious episodes).
Study population (n=40):Median (IQR) ADM serum level:   T0 12.0 (9.4-14.4) µg/mL – T1 7.9 (5.8-10.7) µg/mL   (p<0.001)Median (IQR) C-reactive protein:   T0 1.4 (0.6-3.5) mg/L – T1 1.3 (0.6-5.1) mg/L   (p=0.188)Median (IQR) serum albumin:   T0 44.0 (42.2-46.9) g/L – T1 43.7 (41.5-47.3) g/L   (p=0.533)Median (IQR) PRO2:   T0 0.0 (0.0-6.0) – T1 2.0 (0.0-8.5)   (p=0.027)
Control group (n=40):Median (IQR) ADM serum level:   T0 9.6 (8.1-11.1) µg/mL – T1 10.1 (8.0-11.7) µg/mL (p=1.000)Median (IQR) C-reactive protein:   T0 1.2 (0.4-3.0) mg/L – T1 1.9 (1.0-3.6) mg/L (p=0.020)Median (IQR) serum albumin:   T0 44.9 (43.0-47.1) g/L – T1 45.3 (43.3-47.1) g/L (p=0.876)Median (IQR) PRO2:   T0 0.0 (0.0-4.8) – T1 2.0 (0.0-7.0) (p=0.007)

Conclusions
In this retrospective cohort analysis, 65% of patients were able to continue ADM therapy at a dose of 40 mg ETW for a median of 24 months. Furthermore, in half of the patients who experienced ADM related AE at baseline, the AE disappeared completely. Regardless of ADM serum levels, disease remission should be objectively assessed prior to dose de-escalation, since an elevated baseline CRP predicted relapse following de-escalation with subsequent need for increase of ADM dose. 

Authors
S. RAEVENS (1), A. PARIDAENS (1), S. LEFERE (1), C. CASTELEYN (2), B. JONCKX (3), X. VERHELST (1), H. VAN VLIERBERGHE (1), C. VAN STEENKISTE (1), A. GEERTS (1), L. DEVISSCHER (1), I. COLLE (1) / [1] Ghent University, Ghent, Belgium, Gastroenterology-Hepatology, [2] Ghent University, Ghent, Belgium, Morphology, Veterinary Medicine, [3] ThromboGenics NV, Heverlee, Belgium, /
Introduction Hepatopulmonary syndrome (HPS) is a severe pulmonary complication of liver disease, without medical treatment to date. Pulmonary angiogenesis is known to contribute to HPS pathogenesis and has only been studied in rats till now. However, the majority of experimental interventions requires a mouse model to study disease pathogenesis and future therapeutic options.
Aim
Our aim was to establish a mouse model for HPS and to investigate the potential to counteract pathological angiogenesis in this model as therapeutic strategy for HPS.
Methods Eight-week-old Swiss mice underwent common bile duct ligation (CBDL) or sham surgery and were sacrificed 6 weeks later. HPS was confirmed by hypoxemia on arterial blood gas analysis and intrapulmonary shunting by arterial detection of intravenously injected fluorescent labeled microspheres. Liver and lung tissue was collected in order to study liver fibrosis, pulmonary angiogenesis and inflammation. Scanning electron microscopy (SEM) was performed on vascular corrosion casts to visualize the pulmonary vasculature during cirrhosis ex vivo. Anti-PlGF antibodies (aPlGF Ab, 25 mg/kg 2x/week, ThromboGenics), administered from week 0-6 post-surgery, were tested for their potential to inhibit angiogenesis and ameliorate pulmonary function in CBDL mice.
Results CBDL significantly induced liver fibrosis 6 weeks post-surgery compared to sham, as previously reported. CBDL mice suffered from hypoxemia (mean PaO2 63.2±9.2 mmHg vs. 92.2±6.7 mmHg in control mice, P=0.03) and intrapulmonary shunting as demonstrated by significantly more fluorescent-labeled spheres in their arterial blood compared to sham controls. CBDL resulted in enhanced pulmonary angiogenesis, evidenced by increased pulmonary CD105 and von Willebrand Factor (vWF) immunoreactivity (both P<0.0001) and elevated pulmonary PlGF protein expression (P=0.0072), along with induction of pulmonary monocyte chemoattractant protein 1 (MCP-1) (P=0.0017), compared to control surgery. In addition, SEM revealed regions of disorganized pulmonary angio-architecture in lungs of cirrhotic mice compared to shams. Preventive aPlGF Ab administration effectively neutralized pulmonary PlGF, which resulted in reduced pulmonary CD105 (P=0.007) and vWF immunopositivity (P=0.0049), and decreased pulmonary MCP-1 expression (P=0.06), compared to IgG control treatment in CBDL mice. Moreover, PlGF inhibition led to partial normalization of the pulmonary vascular network as demonstrated by SEM on lung vascular casts. Importantly, mice treated with aPlGF showed normal gas exchange, reflected by physiological PaO2 levels (P=0.025), compared to IgG-treated CBDL mice which suffered from hypoxemia.
Conclusions Pharmacological PlGF inhibition counteracts pulmonary angiogenesis and inflammation and is able to inhibit experimental HPS development in mice. Future research will have to reveal if aPlGF Ab might be an attractive therapeutic strategy for human HPS patients.

Authors
L. WAUTERS (1), V. VAN DER VOORT (2), P. DOBBELS (2), K. HENDRICKX (2), V. CASNEUF (2), J. VANDERVOORT (2) / [1] UZ Leuven, Leuven, Belgium, Gastroenterology, [2] OLV Aalst, Aalst, Belgium, Gastroenterology

Introduction
The impact of antithrombotics on immunochemical fecal occult blood testing (iFOBT) for colorectal cancer (CRC) screening in the general population remains unclear.

Aim

To study the rate of false positive iFOBT and detection of CRC or advanced adenoma's in patients with and without antithrombotics or Aspirin alone.

Methods
A prospective cohort of patients undergoing endoscopy for positive iFOBT in 2015 at 3 affiliated centers in Belgium was analyzed. Medical records were reviewed for demographic and clinical variables, including lower GI symptoms, family history of polyps or CRC and antithrombotics (Aspirin and/or Clopidogrel, Dipyridamole, Ticagrelor, novel anticoagulants and vitamin K antagonists). Endoscopy reports were checked for colorectal pathology. Significant findings were defined as CRC or advanced adenoma’s (sessile serrated adenoma and tubular adenoma of >1cm or with high-grade dysplasia). Rates of false positive iFOBT and detection of CRC or advanced adenoma’s were compared in patients with and without antithrombotics or Aspirin alone.

Results
A total of 524 patients (64% male, median (IQR) age 63.2 (60.2 – 66.4) years) with positive iFOBT were included. Colorectal pathology was confirmed in 379/524 (72%) patients and more commonly in males (70% vs. 48%; p= .03) and with positive family history (16% vs. 8%; p= .02). Significant findings were present in 222/379 (59%) patients with colorectal pathology and more frequently with lower GI symptoms (15% vs. 5%; p= .002). Antithrombotics were prescribed in 129/524 (25%) patients and associated with male gender (78% vs. 59%; p= .0001), older age (65.2 (62.2 – 70.3) vs. 62.3 (58.5 – 66.3) years; p= .0001) and lower GI symptoms (18% vs. 11%; p= .04). Aspirin was used in 105/524 (20%) patients and also associated with male gender (81% vs. 60%; p< .05) and older age (64.6 (61.8 – 69.6) vs. 62.4 (58.8 – 66.3) years; p= .0002). The rate of false positive iFOBT (26% vs. 28%; p= .70) and detection of CRC (6% vs. 6%; p= .79) or advanced adenoma’s (40% vs. 35%; p= .32) were similar in patients with or without antithrombotics. The rate of false positive iFOBT (28% vs. 28%; p= 1) and detection of CRC (6% vs. 6%; p= .98) or advanced adenoma’s (42% vs. 35%; p= .21) were similar in patients with or without Aspirin.

Conclusions
Although antithrombotics were mostly prescribed in male and older patients with an inherent higher cancer risk, detection rates of CRC and advanced adenoma’s were similar. Despite the higher rates of lower GI symptoms, antithrombotics did not lead to more false positive iFOBT. Use of antitrombotics or Aspirin alone does not seem to impact the performance of iFOBT for screening of CRC in the general population.

Authors
T. ROUSSEF (1), S. VANDE VELDE (2), R. DE BRUYNE (2), M. VAN WINCKEL (3), P. SCHELSTRAETE (4), S. VAN BIERVLIET (5) / [1] Ghent University Hospital, Gent, Belgium, Pediatrics, [2] Ghent University Hospital, Gent, Belgium, Pediatric Gastroenterology and nutrition, [3] Ghent University Hospital, Gent, Belgium, pediatric Gastroenterology and nutrition, [4] Ghent University Hospital, Gent, Belgium, Pediatric pneumology and infectious diseases, [5] Ghent University hospital, Ghent, Belgium, Pediatric gastroenterology and nutrition
Introduction Celiac disease (CD) is an autoimmune disease characterized by immune mediated inflammatory damage of the small intestinal mucosa, precipitated by the ingestion of gluten-containing foods. Nonresponse following Hepatitis B virus (HBV) vaccine in a healthy population is 4-10% and can partially be explained by genetic predisposition, especially Human leukocyte antigen (HLA) DQ2 and DQ8 alleles seem to play a primary role. It is known that more than 95% of celiac patients possess these HLA genotypes. Consequently, a lower immunisation rate after HBV vaccine is seen in celiac patients.
Aim
The aim of this study is to prospectively map the responses to HBV vaccine in children with CD. We also investigated if there is a relationship between the patients’ responses to HBV vaccination and the dietary compliance.
Methods At the moment of annual follow-up, we performed a blood analysis and measured the anti-hepatitis B surface antibodies (antiHBs AB) in children with CD followed at the pediatric gastroenterology department of the Ghent university hospital, between 2015 and 2016. Subjects with antiHBs AB <10 IU/L were considered non-responders. Non-responders were advised to take a single intramuscular HBV vaccine booster. Response was checked at the next annual appointment. Compliance to gluten free diet (GFD) and CD activity were monitored as usual, using serum anti-transglutaminase antibody levels (a-TG AB). The results were compared to the 4-10% non-response reported in literature.
Results 71 children with CD were included of which 24% (n=17) were male. The mean age at diagnosis of CD was 6.1 years (range 1–16 years) and 9.5 years (range 3-17 year) at measurement of antiHBs AB. Of the 31 (43.6%) responders to vaccination, 21 (67.7%) showed low response (10-100 IU/L), 8 (25.8%) intermediate response (100-1000IU/L) and 2 (6.5%) a high response (>1000 IU/L). More than half of the patients were non-responders (40 (56.3%)). Until now, for only 13/40 (32.5%) non-responders, antiHBs AB were available after intramuscular revaccination. Of those 53.8% (n=7) acquired immunity after a single HBV booster. The a-TG AB were still positive in 16/71 (22.5%) CD patients. The a-TG AB ranged from 11-392 U/mL (normal value <7 U/mL). Ten of them were non-responders. Control antiHBs AB titre after booster vaccination was available for 3/10. At control all had normal a-TG AB and 2/3 became responders.
Conclusions Non-responsiveness to HBV vaccination was more frequently found in children with CD compared to the literature reported non-response. Since more than half of the CD patients have an insufficient response to HBV vaccination this should be checked. A single booster injection was able to induce a response in more than 50% of patients. Furthermore, compliance to the prescribed GFD may possibly improve the immune response to HBV vaccination in children with CD.

Authors
T. HOLVOET (1), P. BOSSUYT (2), I. CLEYNEN (3), I. DE KOCK (4), P. HINDRYCKX (1), S. VERMEIRE (3), D. LAUKENS (1), M. DE VOS (1) / [1] Ghent University Hospital, Ghent, Belgium, Gastroenterology, [2] Imelda Hospital, Bonheiden, Belgium, Imelda GI Clinical Research Centre, [3] University Hospitals Leuven, Leuven, Belgium, Gastroenterology, [4] Ghent University Hospital, Ghent, Belgium, Radiology
Introduction Fibrostenosis is a common complication of Crohn’s disease (CD) occurring in about one third of patients. Although the pathophysiology of intestinal fibrosis is incompletely understood, evidence suggests a genetic contribution. Previous genetic association studies and candidate gene studies with fibrostenotic CD were based on clinical definitions which lack both sensitivity, specificity and have a high inter-observer disagreement. Additionally, the recent genotype-phenotype analysis by the IIBDGC did not consider the time to development of fibrostenotic disease.
Aim
As the genetic risk may be more important in patients with early fibrostenosis, in this study we aimed to identify novel genetic markers by focussing on early fibrostenotic disease.
Methods In this multicenter, retrospective nested case-control study, performed at the University Hospitals of Ghent and Leuven, computed tomography (CT) and magnetic resonance imaging (MRI) from CD patients obtained between 2002 and 2016 were examined for the presence of ileal fibrostenotic disease. Patients with early fibrostenosis, defined as a the presence of bowel tickening with luminal narrowing and prestenotic dilatation on CT/MRI occurring within 5 years following diagnosis of ileal or ileocolic disease (Montreal L1 or L3), and with available Illumina Immunochip data were included. The control cohort consisted of inflammatory CD patients, also Montreal L1 or L3, without arguments for fibrostenotic disease after min 10 years follow up. Allelic association was assessed using the PLINK v1.07 software.
Results In total, 3.024 CT or MRI scans of 2.042 CD patients were screened. 112 patients were selected because of positive arguments for fibrostenosis occurring within 5 years of diagnosis. Of these, Immunochip data were available in 60 cases, and 49 (82%) had confirmed stenosis by histopathology. 343 inflammatory CD controls with genotype data were included in the analysis. Of the 156.500 SNPs analysed, only rs35223850 in the MIS18BP1 gene passed genome-wide significance level for association with early fibrostenosis (P-value<3.3x10^-7, OR 3.9, 17.5% vs 5% in cases vs controls respectively). The protein encoding MIS18BP1 is known to bind to the SP1 transcription factor, and has been associated with cardiac, liver and kidney fibrosis. Five additional SNPs reached a statistically suggestive significance level of P<5x10^-6, including rs116630177 in the IL23R gene, which is of particular interest as this gene has previously been associated with systemic sclerosis.
Conclusions This carefully phenotyped study reveals an important role for genetic contribution to early development of fibrostenotic complications in CD. Our data suggest a role for MIS18BP1 and the SP1 transcription factor as well as the IL23 pathway in the pathogenesis of early intestinal fibrosis.

Authors
J. HAAS (1), E. BAUGÉ (1), A. VERRIJKEN (2), S. QUEMENER (1), N. HENNUYER (1), F. LALLOYER (1), A. DEPRINCE (1), C. GHEERAERT (1), R. PAUMELLE-LESTRELIN (1), S. CARON-HOUDE (1), L. VAN GAAL (3), P. LEFEBVRE (1), D. DOMBROWICZ (1), S. FRANCQUE (4), B. STAELS (1) / [1] Institut Pasteur, Lille, France, INSERM U1011, [2] Antwerp University Hospital, Edegem, Belgium, Department of Endocrinology, Diabetology and Metabolism, [3] ANTWERP UNIVERSITY HOSPITAL, Edegem, Belgium, Dept. of Gastroenterology and Hepatology, [4] Antwerp University Hospital, Edegem, Belgium, Dept. of Gastroenterology and Hepatology

Introduction
Nonalcoholic fatty liver disease (NAFLD) is rapidly becoming a major global health problem with its prevalence rising in concert with the epidemic of obesity. Critically, the molecular processes leading to the development of NAFLD and its more severe subtype, non-alcoholic steatohepatitis (NASH), remain poorly understood.

Aim

To identify molecular mechanisms implicated in development and resolution of NASH in humans.

Methods
A cohort of 170 patients covering the spectrum of NAFLD were biopsied at baseline and one year following dietary intervention or bariatric surgery totaling 253 biopsies. The biopsies were scored histologically according to the NAFLD Activity Score (NAS) criteria and each patient received a full clinical workup before and after the intervention. Expression microarray was used to assess gene expression changes in these biopsies and identify genes whose expression was correlated with histological features of NAFLD. In animal studies, acute overexpression of human or murine ApoF was achieved using hydrodynamic injection via tail vain, and adenovirus-mediated shRNA expression was employed for transient knockdown of endogenous Apof. All experiments were performed using wildtype C57BL6/J mice fed a normal chow diet.

Results
In the human biopsies, we identified Apolipoprotein F (ApoF) as the strongest transcript inversely correlated with steatosis score in males (Spearman rho=-0.675, nominal p=7.6x10-8). Upon further investigation, we found ApoF also inversely correlated with lobular inflammation scores (Spearman rho=-0.612, nominal p=2.3x10-6), and hence, significantly reduced in males with NASH. These findings were confirmed using publicly available data from previously published NAFLD cohorts. Following bariatric surgery-mediated resolution of NASH, APOF transcript levels were increased nearly 2-fold (nominal p=3.5x10-4). To determine whether ApoF may play a causative role in NAFLD development, we assessed intracellular lipid metabolism using radiolabeled 14C-oleate. We found that transfecting Apof in Hepa1c1c7 cells led to reduced incorporation of the label into phosphatidylcholine (PC) while incorporation into triglycerides (TG) was unaffected. Due to the requirement of PC for efficient VLDL secretion, we suspected that changes in ApoF may affect plasma lipid levels. Indeed, overexpression of either human or murine ApoF in mice led to reduced plasma TG levels, associated with a reduction in hepatic VLDL production. Conversely, acute knockdown of ApoF led to increased plasma cholesterol levels 7 days post injection combined with increased liver weight.

Conclusions
We have identified ApoF as a transcript whose expression is strongly diminished with NAFLD severity and improves following NASH reversion in humans. Through a combination of animal and cell-based studies we demonstrate that reduced ApoF affects phosphatidylcholine homeostasis and leads to increased plasma cholesterol levels and likely elevated hepatic TGs. These findings highlight the importance of hepatic PC metabolism in the development of NASH and suggest ApoF is a novel player in this setting.