1. Gastroenterology Unit, Department of Systems Medicine, University of Rome Tor Vergata, Roma, Italy
2. Gastroenterology and Endoscopy Unit, Edouard Herriot Hospital, Hospices Civils de Lyon, Lyon, France
3. Gastroenterology and Endoscopy Unit, Hospital Centre Cornouaille, Quimper, France
4. Gastroenterology and Endoscopy Unit, Pontchaillou University Hospital, Rennes, France