1. Department of Surgery; University Hospital Düsseldorf; Düsseldorf Germany
2. Translational Centre for Regenerative Medicine; University of Leipzig; Leipzig Germany
3. Department of Radiology; University Hospital Düsseldorf; Leipzig Germany
4. Medical Research Council Centre for Regenerative Medicine; University of Edinburgh; Edinburgh UK
5. Department of Surgery; University Hospital Leipzig; Düsseldorf Germany
6. The Transplant Institute and Division of Gastroenterology; Beth Israel Deaconess Medical Center; Harvard University; Boston MA USA