Association of Heat Production with ^sup 18^F-FDG Accumulation in Murine Brown Adipose Tissue After Stress

• Published in: The Journal of nuclear medicine (1978) Vol. 52; no. 10; p. 1616
• Main Authors: Carter, Edward A, Bonab, Ali A, Paul, Kasie, Yerxa, John, Tompkins, Ronald G, Fischman, Alan J
• Format: Journal Article
• Language: English
• Published: New York Society of Nuclear Medicine 01.10.2011
• Subjects: Body fat; Cold; Heat detection; Laboratory animals
• ISSN: 0161-5505; 1535-5667

Previous studies have demonstrated that cold stress results in increased accumulation of ^sup 18^F-FDG in brown adipose tissue (BAT). Although it has been assumed that this effect is associated with increased thermogenesis by BAT, direct measurements of this phenomenon have not been reported. In the current investigation, we evaluated the relationship between stimulation of ^sup 18^F-FDG accumulation in BAT by 3 stressors and heat production measured in vivo by thermal imaging. Male SKH-1 hairless mice were subjected to full-thickness thermal injury (30% of total body surface area), cold stress (4°C for 24 h), or cutaneous wounds. Groups of 6 animals with each treatment were kept fasting overnight and injected with ^sup 18^F-FDG. Sixty minutes after injection, the mice were sacrificed, and biodistribution was measured. Other groups of 6 animals subjected to the 3 stressors were studied by thermal imaging, and the difference in temperature between BAT and adjacent tissue was recorded (ΔT). Additional groups of 6 animals were studied by both thermal imaging and ^sup 18^F-FDG biodistribution in the same animals. Accumulation of ^sup 18^F-FDG in BAT was significantly (P < 0.0001) increased by all 3 treatments (burn, ~5-fold; cold, ~15-fold; and cutaneous wound, ~15-fold), whereas accumulation by adjacent white adipose tissue was unchanged. Compared with sham control mice, in animals exposed to all 3 stressors, ΔTs showed significant (P < 0.001) increases. The ΔT between stressor groups was not significant; however, there was a highly significant linear correlation (r^sup 2^ = 0.835, P < 0.0001) between the Δ^sub T^ measured in BAT versus adjacent tissue and ^sup 18^F-FDG accumulation. These results establish, for the first time to our knowledge, that changes in BAT temperature determined in vivo by thermal imaging parallel increases in ^sup 18^F-FDG accumulation. [PUBLICATION ABSTRACT]