1. Gastroenterology and Endoscopy Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
2. Postgraduate School of Gastroenterology, Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Milan, Italy
3. Department of Biomedical and Clinical Sciences “L. Sacco”, University of Milan, Milan, Italy