Cold-activated brown adipose tissue in healthy men

Area of Science:

• Endocrinology
• Metabolism
• Human Physiology

Background:

• Brown adipose tissue (BAT) plays a role in regulating body weight and adaptive thermogenesis in animals.
• Previously, BAT was thought to be physiologically insignificant in adult humans.
• This study systematically examined BAT presence, distribution, and activity in lean and obese men.

Purpose of the Study:

• To investigate the presence and activity of brown adipose tissue in lean and obese adult men.
• To correlate brown adipose tissue activity with body composition and energy metabolism.

Main Methods:

• 24 healthy men (10 lean, 14 overweight/obese) were studied under thermoneutral and cold conditions.
• Brown adipose tissue activity was assessed using integrated 18F-fluorodeoxyglucose positron-emission tomography and computed tomography.
• Body composition and energy expenditure were measured using dual-energy x-ray absorptiometry and indirect calorimetry.

Main Results:

• Brown adipose tissue activity was detected in 96% of subjects during cold exposure, but not at thermoneutrality.
• Overweight/obese subjects exhibited significantly lower BAT activity compared to lean subjects.
• Body mass index (BMI) and body fat percentage negatively correlated with BAT activity, while resting metabolic rate positively correlated.

Conclusions:

• Brown adipose tissue is present and metabolically active in a high percentage of young men.
• Reduced BAT activity in overweight and obese individuals suggests its potential as a therapeutic target for obesity management.