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Dive into the research topics where Pieter Demetter is active.

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Featured researches published by Pieter Demetter.


International Journal of Cancer | 2008

Stromal myofibroblasts are drivers of invasive cancer growth

Olivier De Wever; Pieter Demetter; Marcus Mareel; Marc Bracke

Tissue integrity is maintained by the stroma in physiology. In cancer, however, tissue invasion is driven by the stroma. Myofibroblasts and cancer‐associated fibroblasts are important components of the tumor stroma. The origin of myofibroblasts remains controversial, although fibroblasts and bone marrow‐derived precursors are considered to be the main progenitor cells. Myofibroblast reactions also occur in fibrosis. Therefore, we wonder whether nontumorous myofibroblasts have different characteristics and different origins as compared to tumor‐associated myofibroblasts. The mutual interaction between cancer cells and myofibroblasts is dependent on multiple invasive growth‐promoting factors, through direct cell–cell contacts and paracrine signals. Since fibrosis is a major side effect of radiotherapy, we address the question how the main methods of cancer management, including chemotherapy, hormonotherapy and surgery affect myofibroblasts and by inference the surrogate endpoints invasion and metastasis.


Hepatology | 2009

The interleukin‐17 pathway is involved in human alcoholic liver disease

Arnaud Lemmers; Christophe Moreno; Thierry Gustot; Raphaël Maréchal; Delphine Degré; Pieter Demetter; Patricia de Nadai; Albert Geerts; Eric Quertinmont; Vincent Vercruysse; Olivier Le Moine; Jacques Devière

Immune dysregulations in alcoholic liver diseases are still unclear, especially regarding alcoholic hepatitis inflammatory burst. Interleukin‐17 (IL‐17) is known to enhance neutrophil recruitment. We studied the IL‐17 pathway in alcoholic cirrhosis and alcoholic hepatitis. Patients with alcoholic liver disease were compared with patients with chronic hepatitis C virus (HCV) infection or autoimmune liver disease and with healthy controls. IL‐17 plasma levels and peripheral blood mononuclear cell secretion were assessed by enzyme‐linked immunosorbent assay (ELISA) and T cell phenotype by flow cytometry. IL‐17 staining and co‐staining with CD3 and myeloperoxidase were performed on liver biopsy specimens. IL‐17 receptor expression was studied on liver biopsies and in human hepatic stellate cells as well as their response to recombinant IL‐17 by chemotaxis assays. IL‐17 plasma levels were dramatically increased in alcoholic liver disease patients. Peripheral blood mononuclear cells of patients with alcoholic liver disease produced higher amounts of IL‐17, and their CD4+ T lymphocytes disclosed an IL‐17–secreting phenotype. In the liver, IL‐17–secreting cells contributed to inflammatory infiltrates in alcoholic cirrhosis, and alcoholic hepatitis foci disclosed many IL‐17+ cells, including T lymphocytes and neutrophils. In alcoholic liver disease, liver IL‐17+ cells infiltrates correlated to model for end‐stage liver disease score, and in alcoholic hepatitis to modified discriminant function. IL‐17 receptor was expressed in alcoholic liver disease by hepatic stellate cells, and these cells recruited neutrophils after IL‐17 stimulation in a dose‐dependent manner through IL‐8 and growth related oncogen α (GRO‐α) secretion in vitro. Conclusion: Human alcoholic liver disease is characterized by the activation of the IL‐17 pathway. In alcoholic hepatitis, liver infiltration with IL‐17–secreting cell infiltrates is a key feature that might contribute to liver neutrophil recruitment. (Clinical trials number NCT00610597). (HEPATOLOGY 2009;49:646–657.)


Arthritis & Rheumatism | 2001

Immunomodulatory effects of anti-tumor necrosis factor alpha therapy on synovium in spondylarthropathy: histologic findings in eight patients from an open-label pilot study.

Dominique Baeten; Elli Kruithof; Filip Van den Bosch; Pieter Demetter; Nancy Van Damme; Claude Cuvelier; Martine De Vos; Herman Mielants; Eric Veys; Filip De Keyser

OBJECTIVE To assess the effects of treatment with anti-tumor necrosis factor alpha (anti-TNFalpha) on synovial histology in patients with spondylarthropathy (SpA) in order to confirm the effect on peripheral synovitis and to investigate the immunologic mechanisms involved in anti-TNFalpha therapy. METHODS Patients with treatment-resistant SpA were treated with infliximab (5 mg/kg) at weeks 0, 2, and 6 in an open-label pilot study. In 8 patients, synovial biopsy tissues obtained at baseline, week 2, and week 12 were used for histologic and immunohistochemical evaluation. RESULTS In all 8 patients (3 with ankylosing spondylitis, 1 with undifferentiated SpA, and 4 with psoriatic arthritis), there was a clear clinical improvement in the peripheral arthritis after anti-TNFalpha therapy. Histologic analysis of the synovial biopsy tissues indicated that the synovial lining layer thickness tended to decrease, with a significant reduction of CD55+ synoviocytes, at week 12. In the sublining layer, vascularity was reduced at week 12, with a decreased endothelial expression of vascular cell adhesion molecule 1 but not intercellular adhesion molecule 1, platelet endothelial cell adhesion molecule 1, and E-selectin. Although at week 2 and week 12, the number of neutrophils and CD68+ macrophages in the sublining layer was decreased, the overall degree of inflammatory infiltration remained unchanged. This could be related to the lymphocyte infiltration since at week 12, only CD4+ cells (but not CD3+, CD45RO+, and CD8+ cells) tended to decrease, while CD20+ lymphocytes and plasma cells were clearly increased. CONCLUSION The reduction in lining layer thickness, vascularity, and infiltration with neutrophils and macrophages paralleled the beneficial effect of anti-TNFalpha therapy on peripheral synovitis in 8 patients with different subtypes of SpA. The adhesion molecule expression, T cell infiltration, and, most important, B cell infiltration seemed to contrast with previous observations in RA. Although these preliminary data need to be confirmed in a larger cohort, they suggest distinct immunomodulatory mechanisms of anti-TNFalpha in SpA.


Annals of the Rheumatic Diseases | 2000

Comparative study of the synovial histology in rheumatoid arthritis, spondyloarthropathy, and osteoarthritis: influence of disease duration and activity

Dominique Baeten; Pieter Demetter; Claude Cuvelier; F. van den Bosch; Elli Kruithof; N. Van Damme; Gust Verbruggen; Herman Mielants; Eric Veys; F De Keyser

OBJECTIVES To compare the macroscopic and microscopic characteristics of synovial tissue in rheumatoid arthritis (RA), spondyloarthropathy (SpA), and osteoarthritis (OA) after exclusion of possible biases induced by disease duration or activity, or both. METHODS Synovial biopsy specimens were obtained by needle arthroscopy in patients with early RA (n=16), late RA (n=14), early SpA (n=23), and OA (n=12). Macroscopic and microscopic features were scored on a four point scale and analysed as a function of disease duration (early versus late RA), local and systemic disease activity, and diagnosis. RESULTS Except for the maximal synovial lining thickness, no significant differences were seen between early and late RA. For disease activity, synovial histology was only weakly correlated with C reactive protein in RA, but seemed to be strongly dependent on effusion of the biopsied joint in all disease groups. After stratification for local disease activity, no disease related differences were found in patients without joint effusion. In contrast, important differences were found between patients with RA and SpA with active joint effusion. Synovial vascularity was macroscopically increased in SpA versus RA (p=0.017). A straight vessel pattern was only seen in RA, while tortuous vessels were preferentially seen in SpA. Vascularity was also microscopically increased in SpA compared with RA (p=0.031), and correlated with the macroscopic vascularity (rs =0.36, p=0.036). CD3+ (p=0.008), CD4+ (p=0.008), and CD20+ (p=0.024) lymphocytes were overrepresented in RA compared with SpA. The integrin expression in RA was characterised by a decrease of αVβ3 in the synovial lining (p=0.006) and an increase of αVβ5 in the sublining (p<0.001). CONCLUSIONS The immune architecture of the synovial membrane is more dependent on local disease activity than on disease duration. Synovium obtained from clinically affected joints shows important histological differences between RA and SpA.


The Journal of Pathology | 2002

Macrophages expressing the scavenger receptor CD163: a link between immune alterations of the gut and synovial inflammation in spondyloarthropathy.

Dominique Baeten; Pieter Demetter; Claude Cuvelier; Elli Kruithof; Nancy Van Damme; Martine De Vos; Eric Veys; Filip De Keyser

The objective of this study was to investigate CD163+ macrophages in the synovial membrane of patients with spondyloarthropathy (SpA). Immunohistochemistry was performed on synovium of 17 SpA and 18 rheumatoid arthritis (RA) patients, on colonic biopsies of 16 SpA patients and ten healthy controls, and on paired synovial biopsies of eight SpA patients, before and after anti‐TNFα therapy. Phenotype and cytokine production were analysed by flow cytometry. CD163+ macrophages were increased in the synovial lining and sublining in SpA versus RA, as well as in colonic lamina propria in SpA versus controls. The number of CD163+ macrophages in the synovial sublining correlated with C‐reactive protein levels and erythrocyte sedimentation rate. Paralleling the increase of CD163, HLA‐DR was increased in the synovial lining and sublining of SpA. In contrast, the co‐stimulatory molecules CD80 and CD86 and the dendritic cell markers CD1a and CD83 were scarce in SpA synovium. Flow cytometry indicated that CD163+ macrophages expressed high levels of HLA‐DR and could produce in vitro tumour necrosis factor α (TNFα) but not interleukin‐10 (IL‐10). Finally, anti‐TNFα therapy in vivo induced a decrease of CD163+ macrophages in the synovial lining and sublining. In conclusion, macrophages expressing the scavenger receptor CD163 are increased in synovium and in colonic mucosa in SpA, highlighting the relationship between joint and gut in this disease. The correlation with inflammatory parameters, the expression of HLA‐DR, the production of TNFα but not IL‐10, and the reduction by anti‐TNFα therapy support a role for CD163+ macrophages in the synovial inflammation in SpA. Copyright


Mucosal Immunology | 2010

Orally administered L. lactis secreting an anti-TNF Nanobody demonstrate efficacy in chronic colitis

Klaas Vandenbroucke; H de Haard; Els Beirnaert; Torsten Dreier; Marc Lauwereys; Lynn Huyck; J. Van Huysse; Pieter Demetter; Lothar Steidler; Erik Remaut; Claude Cuvelier; Pieter Rottiers

Inflammatory bowel disease (IBD) is a chronic inflammatory gastrointestinal disorder. Systemic treatment of IBD patients with anti-tumor necrosis factor (TNF)-α antibodies has proven to be a highly promising approach, but several drawbacks remain, including side effects related to systemic administration and high cost of treatment. Lactococcus lactis was engineered to secrete monovalent and bivalent murine (m)TNF-neutralizing Nanobodies as therapeutic proteins. These therapeutic proteins are derived from fragments of heavy-chain camelid antibodies and are more stable than conventional antibodies. L. lactis-secreted anti-mTNF Nanobodies neutralized mTNF in vitro. Daily oral administration of Nanobody-secreting L. lactis resulted in local delivery of anti-mTNF Nanobodies at the colon and significantly reduced inflammation in mice with dextran sulfate sodium (DSS)-induced chronic colitis. In addition, this approach was also successful in improving established enterocolitis in interleukin 10 (IL10)–/– mice. Finally, L. lactis-secreted anti-mTNF Nanobodies did not interfere with systemic Salmonella infection in colitic IL10–/– mice.In conclusion, this report details a new therapeutic approach for treatment of chronic colitis, involving in situ secretion of anti-mTNF Nanobodies by orally administered L. lactis bacteria. Therapeutic application of these engineered bacteria could eventually lead to more effective and safer management of IBD in humans.


Journal of Clinical Oncology | 2015

Adjuvant Fluorouracil, Leucovorin, and Oxaliplatin in Stage II to III Colon Cancer: Updated 10-Year Survival and Outcomes According to BRAF Mutation and Mismatch Repair Status of the MOSAIC Study

Thierry André; Armand de Gramont; Dewi Vernerey; Benoist Chibaudel; Franck Bonnetain; Annemilai Tijeras-Raballand; Aurelie Scriva; Tamas Hickish; Josep Tabernero; Jean-Luc Van Laethem; Maria Banzi; E. Maartense; Einat Shacham Shmueli; Göran Carlsson; Werner Scheithauer; Demetris Papamichael; Marcus Möehler; Stefania Landolfi; Pieter Demetter; Soudhir Colote; Christophe Tournigand; Christophe Louvet; Alex Duval; Jean Francois Flejou; Aimery de Gramont

PURPOSE The MOSAIC (Multicenter International Study of Oxaliplatin/Fluorouracil/Leucovorin in the Adjuvant Treatment of Colon Cancer) study has demonstrated 3-year disease-free survival (DFS) and 6-year overall survival (OS) benefit of adjuvant oxaliplatin in stage II to III resected colon cancer. This update presents 10-year OS and OS and DFS by mismatch repair (MMR) status and BRAF mutation. METHODS Survival actualization after 10-year follow-up was performed in 2,246 patients with resected stage II to III colon cancer. We assessed MMR status and BRAF mutation in 1,008 formalin-fixed paraffin-embedded specimens. RESULTS After a median follow-up of 9.5 years, 10-year OS rates in the bolus/infusional fluorouracil plus leucovorin (LV5FU2) and LV5FU2 plus oxaliplatin (FOLFOX4) arms were 67.1% versus 71.7% (hazard ratio [HR], 0.85; P = .043) in the whole population, 79.5% versus 78.4% for stage II (HR, 1.00; P = .980), and 59.0% versus 67.1% for stage III (HR, 0.80; P = .016) disease. Ninety-five patients (9.4%) had MMR-deficient (dMMR) tumors, and 94 (10.4%) had BRAF mutation. BRAF mutation was not prognostic for OS (P = .965), but dMMR was an independent prognostic factor (HR, 2.02; 95% CI, 1.15 to 3.55; P = .014). HRs for DFS and OS benefit in the FOLFOX4 arm were 0.48 (95% CI, 0.20 to 1.12) and 0.41 (95% CI, 0.16 to 1.07), respectively, in patients with stage II to III dMMR and 0.50 (95% CI, 0.25 to 1.00) and 0.66 (95% CI, 0.31 to 1.42), respectively, in those with BRAF mutation. CONCLUSION The OS benefit of oxaliplatin-based adjuvant chemotherapy, increasing over time and with the disease severity, was confirmed at 10 years in patients with stage II to III colon cancer. These updated results support the use of FOLFOX in patients with stage III disease, including those with dMMR or BRAF mutation.


Journal of Clinical Pathology | 2012

Mucinous subtype as prognostic factor in colorectal cancer: a systematic review and meta-analysis.

Johanna Verhulst; Liesbeth Ferdinande; Pieter Demetter; Wim Ceelen

Background Mucinous adenocarcinoma (MAC) of the colorectum has been known and studied for many years. The prognostic significance of this histological subtype remains controversial. The authors reviewed the prognostic significance of mucinous differentiation in colorectal cancer. Materials and methods A systematic web-based search was performed using Web of Knowledge and Medline. Articles published in English, German or French which used the WHO definition of MAC and described cohort studies, case–control studies or cross-sectional studies comparing survival in patients with MAC and adenocarcinoma (AC) not otherwise specified were included. Data on first author, year of publication, country, number of patients included, prevalence of MAC, % stage IV disease, % disease located in the proximal colon, mean age at presentation, % male patients and 5-year overall survival were extracted from individual studies. A fixed-effects meta-analysis model was used for analysis. The primary outcome was survival, expressed as the HR. Differences between categorical outcome parameters were quantified using the RR and corresponding 95% CI. Results 44 studies and 222 256 patients were included. The RR for proximal disease versus distal disease was 1.55 (95% CI 1.53 to 1.58). Mucinous differentiation was less frequent in male subjects (RR 0.93 (95% CI 0.91 to 0.94)). Interestingly, the prevalence of stage IV disease was similar in MAC and AC (RR 0.99 (95% CI 0.96 to 1.02)). Thirty-five articles were included in the survival analysis. A worse survival in MAC versus AC was demonstrated (HR 1.05 (95% CI 1.02 to 1.08)). Conversely, three out of four studies reported a better survival in MAC with microsatellite instability (MSI). Due to heterogeneity a meta-analysis on the effect of MSI was not possible. Conclusion MAC more often originates from the right colon and is less frequent in male subjects. The authors did not identify a difference in the proportion of stage IV patients at presentation. Mucinous differentiation results in a 2–8% increased hazard of death, which persists after correction for stage. More research is needed to define the interaction between mucinous differentiation, MSI and outcome.


BMC Cancer | 2010

Epidermal Growth Factor Receptor and K-RAS status in two cohorts of squamous cell carcinomas

Nancy Van Damme; Philippe Deron; Nadine Van Roy; Pieter Demetter; Alain Bols; Jo Van Dorpe; Filip Baert; Jean-Luc Van Laethem; Franki Speleman; Patrick Pauwels; Marc Peeters

BackgroundWith the availability of effective anti-EGFR therapies for various solid malignancies, such as non-cell small lung cancer, colorectal cancer and squamous cell carcinoma of the head and neck, the knowledge of EGFR and K-RAS status becomes clinically important. The aim of this study was to analyse EGFR expression, EGFR gene copy number and EGFR and K-RAS mutations in two cohorts of squamous cell carcinomas, specifically anal canal and tonsil carcinomas.MethodsFormalin fixed, paraffin-embedded tissues from anal and tonsil carcinoma were used. EGFR protein expression and EGFR gene copy number were analysed by means of immunohistochemistry and fluorescence in situ hybridisation. The somatic status of the EGFR gene was investigated by PCR using primers specific for exons 18 through 21. For the K-RAS gene, PCR was performed using exon 2 specific primers.ResultsEGFR immunoreactivity was present in 36/43 (83.7%) of anal canal and in 20/24 (83.3%) of tonsil squamous cell carcinomas. EGFR amplification was absent in anal canal tumours (0/23), but could be identified in 4 of 24 tonsil tumours.From 38 anal canal specimens, 26 specimens were successfully analysed for exon 18, 30 for exon 19, 34 for exon 20 and 30 for exon 21. No EGFR mutations were found in the investigated samples. Thirty samples were sequenced for K-RAS exon 2 and no mutation was identified. From 24 tonsil specimens, 22 were successfully analysed for exon 18 and all 24 specimens for exon 19, 20 and 21. No EGFR mutations were found. Twenty-two samples were sequenced for K-RAS exon 2 and one mutation c.53C > A was identified.ConclusionEGFR mutations were absent from squamous cell carcinoma of the anus and tonsils, but EGFR protein expression was detected in the majority of the cases. EGFR amplification was seen in tonsil but not in anal canal carcinomas. In our investigated panel, only one mutation in the K-RAS gene of a tonsil squamous cell carcinoma was identified. This indicates that EGFR and K-RAS mutation analysis is not useful as a screening test for sensitivity to anti-EGFR therapy in anal canal and tonsil squamous cell carcinoma.


Laryngoscope | 2005

Neutrophil‐Derived Metalloproteinase‐9 Predicts Healing Quality after Sinus Surgery

Jean-Baptiste Watelet; Pieter Demetter; Coraline Claeys; P. Van Cauwenberge; C. Cuvelier; Claus Bachert

Background: In a recent study, we have shown that gelatinase‐B (metalloproteinase [MMP]‐9) in nasal secretions can have both monitoring and predictive value on the healing outcome after functional endoscopic sinus surgery (FESS) to treat chronic rhinosinusitis (CRS) and nasal polyposis (NP). In this work, we aimed to explore the source of MMP‐9 and the influence of inflammation on MMP‐9 expression and release in nasal tissue and secretions during airway remodelling after surgery.

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Dive into the Pieter Demetter's collaboration.

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Claude Cuvelier

Ghent University Hospital

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Laurine Verset

Université libre de Bruxelles

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Isabelle Salmon

Université libre de Bruxelles

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Nancy Van Damme

Ghent University Hospital

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Jacques Devière

Université libre de Bruxelles

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Raphaël Maréchal

Université libre de Bruxelles

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Wim Ceelen

Ghent University Hospital

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Christine Decaestecker

Université libre de Bruxelles

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Nathalie Nagy

Université libre de Bruxelles

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