Cold-induced thermogenesis requires neutral-lipase-mediated intracellular lipolysis in brown adipocytes.
Level 5 - mechanism / opinion, no new human data
Preclinical animal knockout study
PubMed 39566492 · doi:10.1016/j.cmet.2024.10.018
What was done
Researchers evaluated mice with inducible, brown-adipocyte-specific deletion of adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL), termed BAHKO mice. They examined brown adipose tissue morphology and mitochondrial structure, monitored body temperature maintenance during cold exposure under fed and fasted conditions, and measured brown fat oxidative activity and fatty acid metabolism using [11C]-acetate and [11C]-palmitate PET-CT imaging.
What was found
No quantitative values, exact sample sizes, or p-values were reported in the abstract. Brown adipose tissue from BAHKO mice exhibited hypertrophy and increased lipid droplet size with preserved mitochondrial area and density. Body temperature maintenance during cold exposure was compromised in fasted but not fed BAHKO mice, and PET-CT imaging demonstrated abolished cold-induced brown fat oxidative activity alongside impaired fatty acid metabolism.
Why it matters
This study demonstrates that neutral-lipase-mediated intracellular lipolysis within brown adipocytes is necessary for cold-induced non-shivering thermogenesis in mice during fasting, clarifying the substrate requirements for brown fat activation.
Limits
Findings are derived entirely from an inducible mouse knockout model and lack direct human validation. The abstract reports no numerical data, variance estimates, specific exposure temperatures, or animal sample sizes.
Cited by
- supports Under fasted conditions, cold-induced thermogenesis relies on breaking down triglycerides and oxidizing free fatty acids in the mitochondria to produce heat.