BACKGROUND. Mirabegron is a β3-adrenergic receptor (β3-AR) agonist approved only for the treatment of overactive bladder. Encouraging preclinical results suggest that β3-AR agonists could also improve obesity-related metabolic disease by increasing brown adipose tissue (BAT) thermogenesis, white adipose tissue (WAT) lipolysis, and insulin sensitivity. METHODS. We treated 14 healthy women of diverse ethnicity, 27.5 ± 1.1 y, BMI 25.4 ± 1.2 kg/m2, with 100 mg mirabegron (Myrbetriq extended-release tablet, Astellas Pharma) for four weeks, open-label. The primary endpoint was the change in BAT metabolic activity as measured by [18F]-2-fluoro-D-2-deoxy-D-glucose (18F-FDG) positron emission tomography/computed tomography (PET/CT). Secondary endpoints included resting energy expenditure (REE), plasma metabolites, and glucose and insulin metabolism as assessed by frequently sampled intravenous glucose tolerance test. RESULTS. Chronic mirabegron therapy increased BAT metabolic activity. Whole-body REE was higher, without changes in body weight or composition. Additionally, there were elevations in plasma levels of the beneficial lipoprotein biomarkers high-density lipoprotein (HDL) and ApoA1, as well as total bile acids. Adiponectin, a WAT-derived hormone that has anti-diabetic and anti-inflammatory capabilities, increased with acute treatment and was 35% higher at study completion. Finally, an intravenous glucose tolerance test demonstrated higher insulin sensitivity, glucose effectiveness, and insulin secretion. CONCLUSION. These findings indicate that human BAT metabolic activity can be increased after chronic pharmacological stimulation with mirabegron and support the investigation of β3-AR agonists as a treatment for metabolic disease. TRIAL REGISTRATION. Clinicaltrials.gov NCT03049462. FUNDING. This work was supported by the Intramural Research Program of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), DK075112, DK075116, DK071013, and DK071014.
Alana E. O'Mara, James W. Johnson, Joyce D. Linderman, Robert J. Brychta, Suzanne McGehee, Laura A. Fletcher, Yael A. Fink, Devika Kapuria, Thomas M. Cassimatis, Nathan Kelsey, Cheryl Cero, Zahraa Abdul-Sater, Francesca Piccinini, Alison S. Baskin, Brooks P. Leitner, Hongyi Cai, Corina M. Millo, William Dieckmann, Mary Walter, Norman B. Javitt, Yaron Rotman, Peter J. Walter, Marilyn Ader, Richard N. Bergman, Peter Herscovitch, Kong Y. Chen, Aaron M. Cypess