1. Department of Internal Medicine, Division of Endocrinology, Diabetology, Vascular Disease, Nephrology and Clinical Chemistry, University of Tübingen, Tübingen, Germany
2. Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany
3. German Center for Diabetes Research, Munich-Neuherberg, Germany
4. Section on Experimental Radiology, Department of Diagnostic and Interventional Radiology, University of Tübingen, Tübingen, Germany
5. Institute of Pathology, University of Tübingen, Tübingen, Germany
6. Department of Molecular Biology, Max-Planck-Institute of Biochemistry, Martinsried, Germany