1. Sam and Ann Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio
2. Geriatric Research, Education & Clinical Center, South Texas Veterans Health Care System , San Antonio, Texas , USA
3. Division of Endocrinology and Kogod Center on Aging , Mayo Clinic, Rochester, Minnesota , USA
4. Department of Physiology and Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania , Philadelphia , USA
5. Translational Gerontology Branch, Experimental Gerontology Section, National Institute on Aging, National Institutes of Health , Baltimore, Maryland , USA
6. Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, Cedars Sinai Medical Center , Los Angeles, California , USA