1. Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA
2. Division of Endocrinology and Metabolism, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
3. Department of Cardiology and Angiology, Hannover Medical School, Hannover, Germany
4. Central Microscopy Research Facility, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
5. Division of Cardiovascular Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
6. Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA