1 Department of Liver and Gastrointestinal Diseases, Biodonostia Health Research Institute, Donostia University Hospital, University of the Basque Country (UPV/EHU), San Sebastian, Spain.
2 National Institute for the Study of Liver and Gastrointestinal Diseases, CIBERehd, Instituto de Salud Carlos III, Madrid, Spain.
3 IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.