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Intermittent cold exposure enhances fat accumulation in mice.

Yoo HS, Qiao L, Bosco C, Leong LH, Lytle N, Feng GS, Chi NW, Shao J - PLoS ONE (2014)

Bottom Line: Due to its high energy consuming characteristics, brown adipose tissue (BAT) has been suggested as a key player in energy metabolism.Surprisingly, we found that ICE actually increased adiposity despite enhancing Ucp1 expression in BAT and inducing beige adipocytes in subcutaneous white adipose tissue.ICE did not alter basal systemic insulin sensitivity, but it increased liver triglyceride content and secretion rate as well as blood triglyceride levels.

View Article: PubMed Central - PubMed

Affiliation: Department of Pediatrics, University of California San Diego, La Jolla, California, United States of America.

ABSTRACT
Due to its high energy consuming characteristics, brown adipose tissue (BAT) has been suggested as a key player in energy metabolism. Cold exposure is a physiological activator of BAT. Intermittent cold exposure (ICE), unlike persistent exposure, is clinically feasible. The main objective of this study was to investigate whether ICE reduces adiposity in C57BL/6 mice. Surprisingly, we found that ICE actually increased adiposity despite enhancing Ucp1 expression in BAT and inducing beige adipocytes in subcutaneous white adipose tissue. ICE did not alter basal systemic insulin sensitivity, but it increased liver triglyceride content and secretion rate as well as blood triglyceride levels. Gene profiling further demonstrated that ICE, despite suppressing lipogenic gene expression in white adipose tissue and liver during cold exposure, enhanced lipogenesis between the exposure periods. Together, our results indicate that despite enhancing BAT recruitment, ICE in mice increases fat accumulation by stimulating de novo lipogenesis.

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Related in: MedlinePlus

ICE increases BAT recruitment and has no effects on basal energy expenditure or insulin sensitivity.After 12 days of ICE, samples were collected at 9AM after overnight recovery at room temperature in the fed state. Interscapular brown adipose tissue weight (A) and Ucp1 protein levels (B) were compared between Con and ICE mice. (C) Inguinal fat pads were collected for hematoxylin and eosin staining. BAT-like structures or beige cells are marked with blue arrows. (D) Ucp1 mRNA levels in inguinal fat. (E)Basal blood glucose, (H) TG and (I) FFA. F&G, after 12 days of ICE, insulin challenge test and glucose tolerance test were carried out after an overnight fasting at room temperature. J&K, indirect calorimetry was performed on the same male mice before and after ICE treatment. ICE-treated mice were allowed to recover overnight at room temperature. VO2 was normalized to lean body mass. Data shown are mean ±SEM, n = 4–6.
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pone-0096432-g002: ICE increases BAT recruitment and has no effects on basal energy expenditure or insulin sensitivity.After 12 days of ICE, samples were collected at 9AM after overnight recovery at room temperature in the fed state. Interscapular brown adipose tissue weight (A) and Ucp1 protein levels (B) were compared between Con and ICE mice. (C) Inguinal fat pads were collected for hematoxylin and eosin staining. BAT-like structures or beige cells are marked with blue arrows. (D) Ucp1 mRNA levels in inguinal fat. (E)Basal blood glucose, (H) TG and (I) FFA. F&G, after 12 days of ICE, insulin challenge test and glucose tolerance test were carried out after an overnight fasting at room temperature. J&K, indirect calorimetry was performed on the same male mice before and after ICE treatment. ICE-treated mice were allowed to recover overnight at room temperature. VO2 was normalized to lean body mass. Data shown are mean ±SEM, n = 4–6.

Mentions: Similar to results from cold acclimation studies [26], ICE mice exhibited a significant expansion of interscapular BAT mass and an upregulation of Ucp1 expression in that tissue compared to control mice (Fig. 2A&B). Moreover, their inguinal fat pads contained more beige cells or brown fat-like structure (Fig. 2C) and expressed more Ucp1 mRNA than control (Fig. 2D). These results indicate that ICE treatment increases BAT recruitment.


Intermittent cold exposure enhances fat accumulation in mice.

Yoo HS, Qiao L, Bosco C, Leong LH, Lytle N, Feng GS, Chi NW, Shao J - PLoS ONE (2014)

ICE increases BAT recruitment and has no effects on basal energy expenditure or insulin sensitivity.After 12 days of ICE, samples were collected at 9AM after overnight recovery at room temperature in the fed state. Interscapular brown adipose tissue weight (A) and Ucp1 protein levels (B) were compared between Con and ICE mice. (C) Inguinal fat pads were collected for hematoxylin and eosin staining. BAT-like structures or beige cells are marked with blue arrows. (D) Ucp1 mRNA levels in inguinal fat. (E)Basal blood glucose, (H) TG and (I) FFA. F&G, after 12 days of ICE, insulin challenge test and glucose tolerance test were carried out after an overnight fasting at room temperature. J&K, indirect calorimetry was performed on the same male mice before and after ICE treatment. ICE-treated mice were allowed to recover overnight at room temperature. VO2 was normalized to lean body mass. Data shown are mean ±SEM, n = 4–6.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4008632&req=5

pone-0096432-g002: ICE increases BAT recruitment and has no effects on basal energy expenditure or insulin sensitivity.After 12 days of ICE, samples were collected at 9AM after overnight recovery at room temperature in the fed state. Interscapular brown adipose tissue weight (A) and Ucp1 protein levels (B) were compared between Con and ICE mice. (C) Inguinal fat pads were collected for hematoxylin and eosin staining. BAT-like structures or beige cells are marked with blue arrows. (D) Ucp1 mRNA levels in inguinal fat. (E)Basal blood glucose, (H) TG and (I) FFA. F&G, after 12 days of ICE, insulin challenge test and glucose tolerance test were carried out after an overnight fasting at room temperature. J&K, indirect calorimetry was performed on the same male mice before and after ICE treatment. ICE-treated mice were allowed to recover overnight at room temperature. VO2 was normalized to lean body mass. Data shown are mean ±SEM, n = 4–6.
Mentions: Similar to results from cold acclimation studies [26], ICE mice exhibited a significant expansion of interscapular BAT mass and an upregulation of Ucp1 expression in that tissue compared to control mice (Fig. 2A&B). Moreover, their inguinal fat pads contained more beige cells or brown fat-like structure (Fig. 2C) and expressed more Ucp1 mRNA than control (Fig. 2D). These results indicate that ICE treatment increases BAT recruitment.

Bottom Line: Due to its high energy consuming characteristics, brown adipose tissue (BAT) has been suggested as a key player in energy metabolism.Surprisingly, we found that ICE actually increased adiposity despite enhancing Ucp1 expression in BAT and inducing beige adipocytes in subcutaneous white adipose tissue.ICE did not alter basal systemic insulin sensitivity, but it increased liver triglyceride content and secretion rate as well as blood triglyceride levels.

View Article: PubMed Central - PubMed

Affiliation: Department of Pediatrics, University of California San Diego, La Jolla, California, United States of America.

ABSTRACT
Due to its high energy consuming characteristics, brown adipose tissue (BAT) has been suggested as a key player in energy metabolism. Cold exposure is a physiological activator of BAT. Intermittent cold exposure (ICE), unlike persistent exposure, is clinically feasible. The main objective of this study was to investigate whether ICE reduces adiposity in C57BL/6 mice. Surprisingly, we found that ICE actually increased adiposity despite enhancing Ucp1 expression in BAT and inducing beige adipocytes in subcutaneous white adipose tissue. ICE did not alter basal systemic insulin sensitivity, but it increased liver triglyceride content and secretion rate as well as blood triglyceride levels. Gene profiling further demonstrated that ICE, despite suppressing lipogenic gene expression in white adipose tissue and liver during cold exposure, enhanced lipogenesis between the exposure periods. Together, our results indicate that despite enhancing BAT recruitment, ICE in mice increases fat accumulation by stimulating de novo lipogenesis.

Show MeSH
Related in: MedlinePlus