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Am J Physiol Regul Integr Comp Physiol. 2018 Apr 1;314(4):R584-R597. doi: 10.1152/ajpregu.00332.2017. Epub 2017 Dec 20.

Removal of interscapular brown adipose tissue increases aortic stiffness despite normal systemic glucose metabolism in mice.

Author information

1
Department of Nutrition and Exercise Physiology, University of Missouri , Columbia, Missouri.
2
Office of Animal Resources, University of Missouri , Columbia, Missouri.
3
Endocrine and Diabetes Division, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California.
4
Department of Medicine, David Geffen School of Medicine, University of California at Los Angeles , Los Angeles, California.
5
Dalton Cardiovascular Research Center, University of Missouri , Columbia, Missouri.
6
Child Health, University of Missouri , Columbia, Missouri.

Abstract

Brown adipose tissue (BAT) is considered protective against obesity and related cardiometabolic dysfunction. Indeed, activation of BAT improves glucose homeostasis and attenuates cardiovascular disease development. However, whether a reduction in BAT mass perturbs metabolic function and increases risk for cardiovascular disease remains largely unknown. To address this question, C57BL/6J male mice underwent a sham procedure or surgical bilateral excision of interscapular BAT (iBATx) and were fed a normal chow or a Western diet for 18 wk, creating four groups ( n = 10/group). Mice were housed at 25°C. As expected, the Western diet increased final body weight and adiposity; however, contrary to our hypothesis, iBATx did not potentiate adiposity independent of diet. Furthermore, iBATx did not affect indexes of glycemic control (HbA1c, fasting glucose and insulin, and glucose area under the curve during a glucose tolerance test) and produced minimal-to-no effects on lipid homeostasis. The absence of metabolic disturbances with iBATx was not attributed to regrowth of iBAT or a "browning" or proliferative compensatory response of other BAT depots. Notably, iBATx caused an increase in aortic stiffness in normal chow-fed mice only, which was associated with an increase in aortic uncoupling protein-1. Collectively, we demonstrated that, at 25°C (i.e., limited thermal stress conditions), a substantial reduction in BAT mass via iBATx does not disrupt systemic glucose metabolism, challenging the current dogma that preservation of BAT is obligatory for optimal metabolic function. However, iBATx caused aortic stiffening in lean mice, hence supporting the existence of an interplay between iBAT and aortic stiffness, independent of alterations in glucose homeostasis.

KEYWORDS:

UCP-1; aortic stiffness; brown adipose tissue; glycemic control; metabolic function

PMID:
29351429
PMCID:
PMC5966817
[Available on 2019-04-01]
DOI:
10.1152/ajpregu.00332.2017
[Indexed for MEDLINE]

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