Brief Article
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World J Gastroenterol. Sep 21, 2013; 19(35): 5837-5847
Published online Sep 21, 2013. doi: 10.3748/wjg.v19.i35.5837
Consumption of gluten with gluten-degrading enzyme by celiac patients: A pilot-study
Greetje J Tack, Jolanda MW van de Water, Maaike J Bruins, Engelina MC Kooy-Winkelaar, Jeroen van Bergen, Petra Bonnet, Anita CE Vreugdenhil, Ilma Korponay-Szabo, Luppo Edens, B Mary E von Blomberg, Marco WJ Schreurs, Chris J Mulder, Frits Koning
Greetje J Tack, Jolanda MW van de Water, Chris J Mulder, Department of Gastroenterology and Hepatology, VU University Medical Centre, 1007 MB Amsterdam, The Netherlands
Maaike J Bruins, Luppo Edens, DSM Biotechnology Centre, Alexander Fleminglaan 1, 2613 AX Delft, The Netherlands
Engelina MC Kooy-Winkelaar, Jeroen van Bergen, Frits Koning, Department of Immunohematology and Blood Transfusion, Leiden University Medical Centre, 2300 RC Leiden, The Netherlands
Petra Bonnet, B Mary E von Blomberg, Marco WJ Schreurs, Department of Pathology, VU University Medical Centre, 1007 MB Amsterdam, The Netherlands
Anita CE Vreugdenhil, Department of Paediatrics, University Hospital Maastricht, 6211 LX Maastricht, The Netherlands
Ilma Korponay-Szabo, Department of Paediatrics, University of Debrecen, 6 Debrecen, Hungary
Ilma Korponay-Szabo, Paediatric Research Centre, University of Tampere, FI-33014 Tampere, Finland
Author contributions: Tack GJ and van de Water JMW contributed equally to this work; Tack GJ and van de Water JMW performed the research; Tack GJ, Kooy-Winkelaar EMC, van Bergen J, Bonnet P, Vreugdenhil ACE, Korponay-Szabo I, von Blomberg BME, and Schreurs MWJ contributed to measurements or analyses of the data; Edens L contributed to development of the enzyme; and Bruins MJ, Mulder CJ and Koning F contributed to writing of the manuscript; Tack GJ and van de Water JM contributed equally.
Correspondence to: Greetje J Tack, MD, Department of Gastroenterology and Hepatology, VU University Medical Centre, PO Box 7057, 1007 MB Amsterdam, The Netherlands.
Telephone: +31-20-4440613 Fax: +31-20-4440554
Received: June 11, 2012
Revised: October 5, 2012
Accepted: October 30, 2012
Published online: September 21, 2013

AIM: To assesses the safety and efficacy of Aspergillus niger prolyl endoprotease (AN-PEP) to mitigate the immunogenic effects of gluten in celiac patients.

METHODS: Patients with initial diagnosis of celiac disease as confirmed by positive serology with subtotal or total villous atrophy on duodenal biopsies who adhere to a strict gluten-free diet (GFD) resulting in normalised antibodies and mucosal healing classified as Marsh 0 or I were included. In a randomised double-blind placebo-controlled pilot study, patients consumed toast (approximately 7 g/d gluten) with AN-PEP for 2 wk (safety phase). After a 2-wk washout period with adherence of the usual GFD, 14 patients were randomised to gluten intake with either AN-PEP or placebo for 2 wk (efficacy phase). Measurements at baseline included complaints, quality-of-life, serum antibodies, immunophenotyping of T-cells and duodenal mucosa immunohistology. Furthermore, serum and quality of life questionnaires were collected during and after the safety, washout and efficacy phase. Duodenal biopsies were collected after the safety phase and after the efficacy phase. A change in histological evaluation according to the modified Marsh classification was the primary endpoint.

RESULTS: In total, 16 adults were enrolled in the study. No serious adverse events occurred during the trial and no patients withdrew during the trial. The mean score for the gastrointestinal subcategory of the celiac disease quality (CDQ) was relatively high throughout the study, indicating that AN-PEP was well tolerated. In the efficacy phase, the CDQ scores of patients consuming gluten with placebo or gluten with AN-PEP did not significantly deteriorate and moreover no differences between the groups were observed. During the efficacy phase, neither the placebo nor the AN-PEP group developed significant antibody titers. The IgA-EM concentrations remained negative in both groups. Two patients were excluded from entering the efficacy phase as their mucosa showed an increase of two Marsh steps after the safety phase, yet with undetectable serum antibodies, while 14 patients were considered histologically stable on gluten with AN-PEP. Also after the efficacy phase, no significant deterioration was observed regarding immunohistological and flow cytometric evaluation in the group consuming placebo compared to the group receiving AN-PEP. Furthermore, IgA-tTG deposit staining increased after 2 wk of gluten compared to baseline in four out of seven patients on placebo. In the seven patients receiving AN-PEP, one patient showed increased and one showed decreased IgA-tTG deposits.

CONCLUSION: AN-PEP appears to be well tolerated. However, the primary endpoint was not met due to lack of clinical deterioration upon placebo, impeding an effect of AN-PEP.

Keywords: Celiac disease, Gluten, Enzyme, Prolyl endoprotease, Aspergillus niger prolyl endoprotease, Treatment, Adverse events, efficacy, IgA-tTG intestinal deposits