E Louis

Centre Hospitalier Universitaire de Liège, Luik, Wallonia, Belgium

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Publications (180)665.3 Total impact

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    ABSTRACT: Pancreatic ductal adenocarcinoma is characterized by a high rate of early metastatic relapse. Surgical resection is still recognized as the cornerstone upfront therapy. However, reported 5 years survival rates are inferior to 20-25% even when surgery is followed by chemotherapy. Margins involvement on the surgical specimen (50 to 85%) and lymph node involvement (around 70%) both strongly impact survival. Median survivals are close to those of locally advanced diseases treated by chemotherapy or chemoradiotherapy, 15 to 16 months. This review focuses on adverse prognostic factors, post-operative outcomes and their impact on multimodality therapy completion rates and survivals in patients undergoing upfront surgery. Current data and emerging results from neoadjuvant series could lead to a change in the therapeutic strategy.
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    ABSTRACT: Off-line sample prefractionations applied prior to biomarker discovery proteomics are options to enable more protein identifications and detect low-abundance proteins. This work compared five commercial methods efficiency to raw serum analysis using label-free proteomics. The variability of the protein quantities determined for each process was similar to the unprefractionated serum. A 49% increase in protein identifications and 12.2% of reliable quantification were obtained. A 61 times lower limit of protein quantitation was reached compared to protein concentrations observed in raw serum. The concentrations of detected proteins were confronted to estimated reference values.
    EuPA Open Proteomics 07/2015; 9. DOI:10.1016/j.euprot.2015.07.009

  • Acta gastro-enterologica Belgica 06/2015; 78(1):26-9. · 0.91 Impact Factor
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    ABSTRACT: Background/Purpose: Immune-mediated inflammatory disorders (IMIDs) share many genetic risk factors. Pleiotropy may exist at different levels and most of the underlying mechanisms are still to be uncovered. GWAS have identified hundreds of risk loci for IMIDs but causative genes have been identified in only a handful of cases. Recent fine-mapping efforts indicate that only a minority of risk variants are coding. This suggests that most risk variants will be regulatory hence affecting disease risk via eQTL effects. Methods: To aid in the identification of causative genes for IMIDs, we generated transcriptome information (HT12 arrays) for six blood cell types (CD4, CD8, CD19, CD14, CD15 and platelets) and intestinal biopsies at three anatomical locations (ileum, colon, rectum) for 350 healthy Caucasians. The same individuals were genotyped with SNP arrays interrogating > 700K variants, augmented by imputation from the 1KG project. To detect cis-eQTL we tested variants within 0.5 megabase windows centered on the tested probe. The nominal p-value of the best SNP within a cis-window was Sidak-corrected for the window-specific number of independent tests. The corresponding best, Sidak-corrected p-values for each probe were jointly used to estimate their respective false discovery rate.To identify likely causative genes in GWAS identified risk loci variants and also better understand pleiotropic effects, we (i) developed a method that quantifies the correlation between “disease association pattern” (DAP) and “eQTL association pattern” (EAP) and provides an empirical estimate of its significance, and (ii) evaluated the effect of fitting known risk variants as covariates in the eQTL analysis following Nica et al. (2010). We applied both approaches to celiac disease (CE) and rheumatoid arthritis (RA) and the second one to type one diabetes (T1D), multiple sclerosis (MS), systemic lupus erythematosus (SLE), ankylosing spondylitis (AS) and psoriasis (PSO). Results: We detected > 16000 significant cis-eQTL, with a degree of sharing between cell types ranging from 38 to 90% highlighting the utility of our multi-tissue panel. GWAS variants were drivers of ciseQTL effects across the different tissues in 399 tests (23.6%), mostly in CD4 cells, and pinpointing 64 new gene-disease associations (3.7%). The number of shared loci and shared eQTL were highly correlated (rho=0.66).RA and SLE showed the highest degree of sharing. Conclusions: We identified new potential candidate genes for IMIDs and characterized pleiotropic effects through ciseQTL mapping in GWAS loci. These findings could shed a light on IMIDs pathogenesis and co-occurrence. Latest results will be presented.
    cold spring harbor laboratory THE BIOLOGY OF GENOMES; 05/2015
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    ABSTRACT: The therapeutic armamentarium in Crohn's disease includes mesalazine, steroids (including topical drugs), anti-metabolites (purines, methotrexate), anti-TNFα antibodies and, more recently, selective inhibitors of lymphocytes homing (vedolizumab). The efficacy of these drugs has been shown in pivotal phase 3 placebo-controlled trials and meta-analyses. However, the use of these drugs in routine practice still remains ill-defined. Those are rather the cohort studies, natural history data and therapeutic strategy trials that help the clinician to determine, for each individual patient, the treatment leading to an optimal benefit/risk profile, aiming at moving from evidence-based medicine towards personalized medicine.
    Revue médicale de Liège 05/2015; 70(5-6):316-20.
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    ABSTRACT: Background We aimed to investigate the 163 known loci and top SNP associated with inflammatory Bowel Disease (IBD) in a non- Caucasian Moroccan IBD cohort. Methods We genotyped 549 non- Caucasian Moroccan individuals with 285 IBD patients (211 Crohn's disease (CD), 63 Ulcerative colitis (UC) and 11 Indeterminate colitis (IC)) and 264 controls on custom designed Immunochips from ILLUMINA®. We considered the 163 loci and top SNPs associated with IBD in Caucasian individuals and negative controls matched for the minor allele frequencies (MAF). After quality controls, association analysis was done using PLINK and population stratification was corrected using the first five principal components as covariates. Simulation tests with random groups of SNP (outside the 163 loci and matched for MAF) and regions (outside the 163 IBD loci and matched for the number of independent tests) were used to test the significance of the results. Results We identified 10 regions significantly associated with IBD and UC (Table1). “Table 1: ten top SNP/loci significantly associated with IBD and UC” Surprisingly, none of NOD2 variants were found to be associated with IBD moroccan population. Increasing the sample size of the used cohort will definitively help to detect more IBD loci/SNPs associated with Moroccan IBD. Conclusion This is the first genetic study conducted in a large population of Moroccan IBD patients. Ten loci/top SNP were significantly associated with IBD and UC. Interestingly, none of the NOD2 variants were found to be associated to CD/UC and Moroccan IBD.
    ECCO 2015; 02/2015

  • Acta gastro-enterologica Belgica 01/2015; 78:26-29. · 0.91 Impact Factor
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    ABSTRACT: Lifetime prevalence of inflammatory bowel disease (IBD) is reaching an alarming rate of >1/400 in industrialized societies. Improved understanding of disease pathogenesis is essential to develop more effective preventive, diagnostic and therapeutic measures. Genome-wide association studies (GWAS) have identified ~ 160 risk loci contributing to inherited predisposition to IBD, leading to the identification of new perturbed pathways and potential drug targets. Nevertheless, causative genes and variants remain unknown for the vast majority of risk loci. GWAS loci are likely to be regulatory and therefore alter expression levels of other genes. We hypothesize that if an IBD associated SNP is an expression quantitative loci (eQTL)-the " disease-association pattern " (DAP) should mirror the " eQTL association pattern " (EAP) of the causative gene if looking in the right target tissue(s). With this premise, our project aims to detect causative genes implicated in IBD's susceptibility through the evaluation of trans-eQTLs within GWAS loci. To this purpose, nine blood cell types and ileal, colonic and rectal biopsies have been collected for 330 healthy individuals of Northern European descent. All individuals have been genotyped with the OmniExpress Illumina array interrogating > 700K genetic variants. Transcriptome analysis has been conducted for all individuals and all cell/tissue types using Illumina HT12 arrays interrogating > 47,000 transcripts. Genotype and transcriptome data have undergone rigorous quality control. Transcriptome data have been pretreated variance stabilizing transformation, QQ normalization and correction for random and fixed effects in each cell type. Only expression probes mapped against Refseq have been considered. Genomic positions have been recovered and probes mapping to more than one genomic position (taking into account splice junctions with Tophat software) with a 96% identity have been discarded. Trans-eQTL mapping will be conducted on a SNP-by-SNP basis using linear regression (additive model) with PLINK software. In order to circumvent genome wide multiple testing penalty, we will test for a given SNP in the genome, any evidence for an excess of low p-values when testing its effect on the expression of genes located on other chromosomes or far away on the same chromosome. Confirmation of putative multigene transregulators will afterwards be performed by RNAseq experiments. We will then quantify the resemblance between DAP in the 160 GWAS-identified risk loci (raw data from IIBDGC plus imputed data) and " multigene trans-EAP " with Spearman's rank correlation. We will also evaluate the biological relevance of this list by performing a network analysis after adding the identified trans targets to the list of previously identified positional candidate genes (mapping to GWAS-identified IBD risk loci). Finally, as a the ultimate proof of causality, the selected genes will be resequenced in 3,000 IBD cases and 3,000 controls, using 600 DNA pools of 10 individuals with Illumina Truseq Amplicon. With this strategy, we expect to detect new causative variants that may constitute new drug targets for IBD. Latest results will be presented.
    BeMGI, Auditoire Léon Fredericq GIGA building B34, Level 5 University of Liège Avenue de l’Hopital 1 4000 Liège (Sart Tilman), Belgium; 04/2014
  • J Tack · E Louis · V Persy · D Urbain ·
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    ABSTRACT: Acid peptic diseases such as peptic ulcer and gastrointestinal reflux disease have a high prevalence; they can have an important impact on the patient's quality of life and generate a considerable health care cost. Proton pump inhibitors are the most potent pharmacological inhibitors of gastric acid secretion currently available and are the mainstay medical therapy for acid peptic diseases. This review provides primary care clinicians with best practice guidelines for optimal use of these drugs.
    Revue médicale de Liège 03/2014; 69(3):139-45.
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    ABSTRACT: Our goals were to assess the prevalence of biological and tissue remission in routine practice in Crohn's disease, and to evaluate the correlation between biological or tissue remission and clinical or demographic characteristics as well as their impact on disease outcome. We performed a retrospective monocenter study. Biological remission was defined by a CRP < 5 mg/I. Tissue remission was defined by the absence of ulcer at endoscopy and/or absence of signs of acute inflammation at MRI. Association with demographic, clinical and laboratory markers was studied by logistic regression models and rates of relapses, hospitalizations and surgeries were compared using the logrank test. Among the 263 patients included, 147 were in clinical remission; 102/147 (69%) were in biological remission. Fifty-six patients also had morphological evaluation: 37 (66%) were in tissue remission. Biological remission was associated with older age, higher hemoglobin and lower BMI. Tissue remission was associated with older age, lower platelets count, absence of previous surgery, and the use of immunosuppressant. Time-to-relapse was significantly longer in patients with biological remission and in patients with tissue remission as compared to patients without biological or tissue remission. Among the patients in clinical remission seen as outpatients, two thirds were either in biological and/or tissue remission. Biological and/or tissue remission was associated with a better outcome than clinical remission alone.
    Acta gastro-enterologica Belgica 03/2014; 77(1):41-6. · 0.91 Impact Factor

  • C. Pirard · E. Louis · C. Reenaers ·

    Journal of Crohn s and Colitis 02/2014; 8:S137-S138. DOI:10.1016/S1873-9946(14)60302-0 · 6.23 Impact Factor

  • Journal of Crohn s and Colitis 02/2014; 8:S274. DOI:10.1016/S1873-9946(14)60615-2 · 6.23 Impact Factor
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    ABSTRACT: Background and aims In Crohn's disease, correlation between clinical assessment and disease activity at tissue level is weak. Our aim was to evaluate the value of serum calprotectin as a biomarker for Crohn's disease. Methods The STORI trial patients (n = 115) were studied at baseline, in clinical remission before infliximab withdrawal, or at the time of relapse after infliximab withdrawal. Forty healthy controls were also studied. Serum calprotectin level was measured by ELISA. Data were analyzed through correlation analyses, Kaplan Meier curves and Cox model, using available Crohn's Disease Activity Index (CDAI), Crohn's Disease Endoscopic Index of Severity (CDEIS), fecal calprotectin and C-reactive protein levels (hsCRP). Results Median serum calprotectin was 8892 ng/mL (range: 410–125,000 ng/mL) in Crohn disease patients as compared with 1318 ng/mL (range: 215.8–3770 ng/mL) in controls (P < 0.0001). Serum calprotectin was significantly higher for active disease (median = 19,584 ng/mL) than for inactive disease (median = 8353 ng/mL) (P < 0.0001). Serum calprotectin correlated with hsCRP (r = 0.4092, P < 0.0001) and CDAI (r = 0.4442, P < 0.0001), but not with CDEIS, on the contrary to fecal calprotectin (r = 0.6458, 0.5515, 0.2577 with P < 0.0001, P < 0.0001, P = 0.019 respectively). In multivariate analysis, serum calprotectin used as a discrete variable (threshold: 5675 ng/ml), appeared complementary to hsCRP (> 5 mg/l) and fecal calprotectin (> 250 μg/g) to predict relapse after infliximab withdrawal (P = 0.0173, 0.0024 and 0.0002; HR: 3.191, 3.561 and 4.120). Conclusions As a CD biomarker, serum calprotectin has a similar profile as hsCRP. It is also complementary to fecal calprotectin and hsCRP for prediction of relapse after infliximab withdrawal.
    Journal of Crohn s and Colitis 12/2013; 7(12):e678–e683. DOI:10.1016/j.crohns.2013.06.008 · 6.23 Impact Factor
  • J Tack · E Louis · V Persy · D Urbain ·
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    ABSTRACT: Heartburn, reflux and epigastric pain are frequently encountered symptoms in primary care medicine. Acid peptic diseases such as peptic ulcer and gastrointestinal reflux disease have a high prevalence, can have important impact on patient quality of life and represent a considerable health care cost. Proton pump inhibitors (PPIs) are the most potent pharmacological inhibitors of gastric acid secretion currently available and are the mainstay medical therapy for acid peptic diseases. This review summarizes current evidence on treatment of acid-peptic diseases with proton pump inhibitors and provides primary care clinicians with best practice guidelines for optimal use of these drugs.
    Acta gastro-enterologica Belgica 12/2013; 76(4):393-402. · 0.91 Impact Factor
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    ABSTRACT: The thyrogastric autoimmune syndrome (TAS) was described in patients in whom the serum cross-reacted both with gastric parietal cells antigens and thyroid antigens. We report two cases illustrating the spectrum of pathogical features of TAS. The first case associates Hashimoto's thyroiditis and anemia perniciosa,and develops a gastric neuroendocrine tumor during follow up. The second case presents with a Graves' disease and an autoimmune reversible gastritis, secondary to Helicobacter pylori. Whereas type III autoimmune polyendocrinopathy is rare, TAS is frequent in our experience. Some 13% (32/240) of patients that we have prospectively followed affected with thyroiditis have also autoimmune gastritis. Helicobacter pylori is clearly implicated in 16% of autoimmune gastritis cases. Infection, malabsorption and gastritis are potentially reversible after bacterial eradication treatment. In the other 84% of gastritis patients, no histological or serological proof of Helicobacter pylori is found. Gastric autoimmunity is then irreversible, leading to gastric severe atrophy, hypochlorhydria and hypergastrinemia. Hypergastrinemia stimulates enterochromaffin cell hyperplasia, possibly progressing to neuroendocrine tumors. We propose a diagnostic approach to improve the characterization of TAS. We review the literature on the subject and discuss some interesting animal models of infectious gastric autoimmunity.
    Revue médicale de Liège 11/2013; 68(11):579-84.
  • V Ledouble · E Beck · P Peters · A Lamproye · E Louis ·
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    ABSTRACT: There is a long-recognized association between cancer and venous thromboembolism. Venous thrombosis is the most common paraneoplastic complication. We describe a case of rupture of esophageal varices in a patient with a paraneoplastic portal thrombosis. We highlight the links between venous thromboembolism and cancer and also discuss treatment and prognostic factors.
    Revue médicale de Liège 09/2013; 68(7-8):382-6.

  • Annales d Endocrinologie 09/2013; 74(4):294. DOI:10.1016/j.ando.2013.07.171 · 0.87 Impact Factor
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    J. M. Benitez · E. Louis ·

    Alimentary Pharmacology & Therapeutics 09/2013; 38(5). DOI:10.1111/apt.12416 · 5.73 Impact Factor

Publication Stats

3k Citations
665.30 Total Impact Points


  • 1994-2015
    • Centre Hospitalier Universitaire de Liège
      • Department of Pathology
      Luik, Wallonia, Belgium
  • 1998-2013
    • University of Liège
      • • Department of Gastroenterology
      • • Department of Pathology
      • • Department of Pneumology
      Luik, Walloon, Belgium
    • University of Leuven
      Louvain, Flemish, Belgium
  • 2004-2005
    • Free University of Brussels
      • Department of Gastroenterology
      Bruxelles, Brussels Capital Region, Belgium
  • 1998-1999
    • University of Southampton
      Southampton, England, United Kingdom
  • 1995
    • Province de Liège
      Luik, Wallonia, Belgium