1. Diabetes Division St. Josef-Hospital, Ruhr University Bochum, Bochum, Germany
2. Department of General and Visceral Surgery, St. Josef-Hospital, Ruhr University Bochum, Bochum, Germany
3. David Geffen School of Medicine, University of California, Los Angeles, CA, US
4. Institue of Pathology, Ruhr University Bochum, Bochum, Germany
5. Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, UK