1. Department of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University, Düsseldorf 40225, Germany
2. Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, Düsseldorf 40225, Germany
3. German Center for Diabetes Research (DZD e.V.), Düsseldorf 40225, Germany;