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 μg/mL versus 18 ± 11 μg/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.
Highlights
The role and presence of brown adipose tissue (BAT) in humans is intriguing, but far to be clearly understood
Active BAT was firstly described through 18F-FDG positron emission tomography (PET) in patients affected by adrenal phaeochromocytoma (PHEO) as intense uptake by BAT reduced after removal of PHEO [4, 5] PHEO may represent a unique model in vivo for the evaluation of BAT in subjects exposed to high levels of catecholamine, which represent important regulator of BAT
We found a positive correlation between serum adiponectin and vanilly mandelic acid (VMA) values (r = 0.60, P < 0.01) in all patients with PHEO
Summary
The role and presence of brown adipose tissue (BAT) in humans is intriguing, but far to be clearly understood. BAT in humans might play an important role in thermogenesis and possibly energy expenditure [1]. Recent findings suggest that BAT may be more prevalent and active in adult humans than ever thought [2]. BAT is normally present in the human fetus, gradually decreasing over the first decade of life [3]. Remnants of BAT in adults are usually found in the neck, mediastinum, axilla, retroperitoneum, paravertebral regions, and abdominal wall [3]. Active BAT was firstly described through 18F-FDG positron emission tomography (PET) in patients affected by adrenal phaeochromocytoma (PHEO) as intense uptake by BAT reduced after removal of PHEO [4, 5] PHEO may represent a unique model in vivo for the evaluation of BAT in subjects exposed to high levels of catecholamine, which represent important regulator of BAT
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
