title: Brown fat expresses adiponectin in humans.
abstract: The presence of brown adipose tissue (BAT) in humans is unclear. Pheochromocytomas (PHEO) are rare tumors of neuroectodermal origin which occur in 0.1-0.2% of patients with hypertension. We sought to evaluate the presence and activity of BAT surrounding adrenal PHEO in a well-studied sample of 11 patients who were diagnosed with PHEO and then underwent adrenalectomy. Areas of white fat (WAT) and BAT surrounding PHEO were obtained by Laser Capture Microdissection for analysis of uncoupling protein (UCP)-1 and adiponectin mRNA expression. Adiponectin and UCP-1 mRNA levels were significantly higher in BAT than in WAT (0.62 versus 0.15 and 362.4 versus 22.1, resp., P < 0.01 for both). Adiponectin mRNA levels significantly correlated with urinary metanephrines (r = 0.76, P < 0.01), vanilly mandelic acid (VMA) (r = 0.95, P < 0.01), and serum adiponectin levels (r = 0.95, P < 0.01). Serum adiponectin levels significantly decreased (24.2 ± 2  μ g/mL versus 18 ± 11  μ g/mL, P < 0.01) after adrenalectomy in PHEO subjects. This study provides the following findings: (1) BAT surrounding PHEO expresses adiponectin and UCP-1 mRNA, (2) expression of adiponectin mRNA is significantly higher in BAT than in WAT surrounding PHEO, and (3) catecholamines and serum adiponectin levels significantly correlate with BAT UCP-1 and adiponectin mRNA.
authors.affiliation: Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL 33136, USA.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Iacobellis
authors.affiliation: Department of Radiological Sciences, Oncology and Anatomical Pathology, Sapienza University of Rome, 00165 Rome, Italy.
authors.forename: Cira
authors.initials: C
authors.lastname: Di Gioia
authors.affiliation: Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, 155 Viale del Policlinico, 00165 Rome, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Petramala
authors.affiliation: Department of Radiological Sciences, Oncology and Anatomical Pathology, Sapienza University of Rome, 00165 Rome, Italy.
authors.forename: Caterina
authors.initials: C
authors.lastname: Chiappetta
authors.affiliation: Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, 155 Viale del Policlinico, 00165 Rome, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Serra
authors.affiliation: Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, 155 Viale del Policlinico, 00165 Rome, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Zinnamosca
authors.affiliation: Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, 155 Viale del Policlinico, 00165 Rome, Italy.
authors.forename: Cristiano
authors.initials: C
authors.lastname: Marinelli
authors.affiliation: Department of Surgery "P. Valdoni", Sapienza University of Rome, 00165 Rome, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Ciardi
authors.affiliation: Department of Surgery "P. Valdoni", Sapienza University of Rome, 00165 Rome, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: De Toma
authors.affiliation: Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, 155 Viale del Policlinico, 00165 Rome, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Letizia