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brown adipose tissue

Anatomy: - thermogenic adipose tissue found in interscapular regions, the mediastinum & other regions - in human adults, the largest depot of brown fat is stored above the clavicles [3] Physiology: - it is most abundant in hibernating animals but also occurs in humans, especially newborns. - the thermogenic properties & brown color may be due to mitochondria in which electron transport is uncoupled from production of stored energy in the form of ATP. - brown fat protects against glucose intolerance & vascular disease [2] - humans with brown fat have - lower blood glucose & serum triglyceride levels & higher HDL cholesterol levels - lower rates of type 2 diabetes, dyslipidemia, coronary artery disease, atrial fibrillation/flutter, cerebrovascular disease, congestive heart failure, & hypertension - benefits of having brown fat are most pronounced in overweight or obese persons [2] - sympathetic innervation of browm fat occurs via the Edinger-Westfall nucleus & oculomotor nerve (cranial nerve-3) & maybe the trochlear nerve (cranial nerve 4) [3] - KLF15 maintains white adipocytes selectively within white adipose tissue - deletion of KLF15 is sufficient to induce beige adipocytes (brown fat) [4] - direct regulation of ADRB1 is a molecular mechanism for this Clinical significance: - brown fat deposits in human adults are highly metabolically active but small in size, thus likely contribute little to whole body energy metabolism [3]

Related

mitochondrial brown fat uncoupling protein 1; UCP 1; thermogenin (UCP1, SLC25A7)

General

adipose tissue

References

  1. Stedman's Medical Dictionary 27th ed, Williams & Wilkins, Baltimore, 1999.
  2. Becher T et al. Brown adipose tissue is associated with cardiometabolic health. Nat Med 2021 Jan; 27:58. PMID: 33398160 https://www.nature.com/articles/s41591-020-1126-7
  3. Southwick C Scientists Find the 'On' Switch for Energy-Burning Brown Fat. Medscape. Oct 17, 2023 https://www.medscape.com/s/viewarticle/997453 - Mori S, Beyer RS, Bernardes de Souza B et al Sympathetic innervation of the supraclavicular brown adipose tissue: A detailed anatomical study. PLOS One. 2023. Oct 4 PMID: 37792692 PMCID: PMC10550181 Free PMC article https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0290455
  4. Stewart J Scientists May Finally Know How to Turn White Fat Into Brown. Medscape. July 10, 2024 https://www.medscape.com/viewarticle/scientists-may-finally-know-how-turn-white-fat-brown-2024a1000co9 - Li L, Feldman BJ White adipocytes in subcutaneous fat depots require KLF15 for maintenance in preclinical models. J Clin Invest. 2024 Jul 1;134(13):e172360 PMID: 38949025 PMCID: PMC11213504 Free PMC article.