1. Department of Gastroenterology and Hepatology and
2. Hubrecht Institute for Developmental Biology and Stem Cell Research, 3584 CT Utrecht, The Netherlands
3. University Medical Centre Utrecht, 3584 CX Utrecht, The Netherlands
4. Present address: Department of Gastroenterology and Hepatology, University Medical Centre, Utrecht, 3584 CX Utrecht, The Netherlands
5. Department of Surgery, Erasmus MC, University Medical Centre Rotterdam, 3015 CE Rotterdam, The Netherlands
6. Present address: Department of Microbiology, Tergooiziekenhuizen, 1201 DA Hilversum, The Netherlands