Changes in brown adipose tissues and coxsackievirus B pathogenesis in mice on acute and chronic cold exposure

1970 ◽  
Vol 16 (9) ◽  
pp. 833-839 ◽  
Author(s):  
E. I. Grodums ◽  
G. Dempster

On acute cold exposure the normal brown adipose cells in the mouse interscapular pad underwent morphological changes apparently as a result of loss and redistribution of the intracellular lipid globules; on continued cold exposure the globules increased in numbers and size. If adult female mice were inoculated with coxsackievirus B-3 during acute cold exposure and returned to normal room temperature soon afterwards, the viral damage in the brown adipose tissues was seriously aggravated; if on the other hand they were left in the cold for the duration of the infection, the damage was aggravated to a lesser degree. Finally, if cold-acclimated mice were inoculated the lesion was localized in one area of the pad.In contrast, the myocardial damage was aggravated only in those mice which were inoculated during acute cold exposure and left in the cold. The cox. B-3 pathogenesis in the brain showed no clear-cut variations resulting from changes in the ambient temperature. The infectious amount of virus recovered from the heart and brain appeared to be greater and persist longer, if the mice were subjected to a prolonged cold exposure.The cold exposure, however, failed completely to increase the age susceptibility of mice to cox. B-2.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Haruka Kimura ◽  
Tomohisa Nagoshi ◽  
Yuhei Oi ◽  
Akira Yoshii ◽  
Yoshiro Tanaka ◽  
...  

AbstractIncreasing evidence suggests natriuretic peptides (NPs) coordinate inter-organ metabolic crosstalk with adipose tissues and play a critical role in energy metabolism. We recently reported A-type NP (ANP) raises intracellular temperature in cultured adipocytes in a low-temperature-sensitive manner. We herein investigated whether exogenous ANP-treatment exerts a significant impact on adipose tissues in vivo. Mice fed a high-fat-diet (HFD) or normal-fat-diet (NFD) for 13 weeks were treated with or without ANP infusion subcutaneously for another 3 weeks. ANP-treatment significantly ameliorated HFD-induced insulin resistance. HFD increased brown adipose tissue (BAT) cell size with the accumulation of lipid droplets (whitening), which was suppressed by ANP-treatment (re-browning). Furthermore, HFD induced enlarged lipid droplets in inguinal white adipose tissue (iWAT), crown-like structures in epididymal WAT, and hepatic steatosis, all of which were substantially attenuated by ANP-treatment. Likewise, ANP-treatment markedly increased UCP1 expression, a specific marker of BAT, in iWAT (browning). ANP also further increased UCP1 expression in BAT with NFD. Accordingly, cold tolerance test demonstrated ANP-treated mice were tolerant to cold exposure. In summary, exogenous ANP administration ameliorates HFD-induced insulin resistance by attenuating hepatic steatosis and by inducing adipose tissue browning (activation of the adipose tissue thermogenic program), leading to in vivo thermogenesis during cold exposure.


1984 ◽  
Vol 4 (11) ◽  
pp. 933-940 ◽  
Author(s):  
Stewart W. Mercer ◽  
Paul Trayhurn

Genetically obese (ob/ob) mice develop insulin resistance in brown adipose tissue during the fifth week of life. Prior to this, at 26 days of age, oh/oh mice show a substantial increase in GDP binding to brownadipose-tissue mitochondria during acute cold exposure. When insulin resistance in brown fat develops, by 35 days of age, the increase in GDP binding in response to cold is markedly reduced. Studies with 2-deoxyglucose suggest that insulin resistance in brown adipose tissue could impair thermogenic responsiveness during acute cold exposure by limiting the ability of the tissue to take up glucose.


1972 ◽  
Vol 18 (5) ◽  
pp. 577-582
Author(s):  
E. I. Grodums

Coxsackievirus (cox.) B-3 pathogenicity was markedly augmented in weanling and adult mice during a reserpine treatment. In both age groups the mortality rose to 100% after the 1st week of inoculation.In the olfactory bulb of the reserpine-treated weanling mice the score of viral lesions was 80% compared to 2% in the non-treated. In the heart of the reserpine-treated infected mice it was 62%, while it was 40% without reserpine. In the adult mice the viral tissue damage was aggravated in the interscapular brown adipose pad and the olfactory bulb. Moreover, the viral lesions in the reserpine-treated mice in both age groups showed some striking morphological differences when compared with mice injected with the virus only.The recovered virus yielded higher titers in the reserpine-treated mice in both age groups. In the adult reserpine-treated mice the LD50 of the cox. B-3 recovered from the brain and heart were as high as in the weanlings.


2020 ◽  
Author(s):  
Bruno Halpern ◽  
Marcio C Mancini ◽  
Caroline Mendes ◽  
Camila Maria Longo Machado ◽  
Silvana Prando ◽  
...  

Abstract Objective: Melatonin has been shown to increase brown adipose tissue (BAT) mass, which can lead to important metabolic effects, such as bodyweight reduction and glycemic improvement. However, BAT mass can only be measured invasively and. the gold standard for non-invasive measurement of BAT activity is positron emission tomography with 2-deoxy-2-[fluorine-18] fluoro-D-glucose (18F-FDG PET). There is no study, to our knowledge, that has evaluated if melatonin influences BAT activity, measured by this imaging technique in animals. Methods: Three experimental groups of Wistar rats (control, pinealectomy, and pinealectomy replaced with melatonin) had an 18F-FDG PET performed at room temperature and after acute cold exposure. The ratio of increased BAT activity after cold exposure/room temperature was called “acute thermogenic capacity” (ATC) We also measured UCP-1 mRNA expression to correlate with the 18F-FDG PET results. Results: Pinealectomy led to reduced acute thermogenic capacity, compared with the other groups, as well as reduced UCP1 mRNA expression.Conclusion: Melatonin deficiency impairs BAT response when exposed to acute cold exposure. These results can lead to future studies of the influence of melatonin on BAT, in animals and humans, without needing an invasive evaluation of BAT.


1996 ◽  
Vol 271 (5) ◽  
pp. R1115-R1122 ◽  
Author(s):  
R. B. McDonald ◽  
M. Florez-Duquet ◽  
C. Murtagh-Mark ◽  
B. A. Horwitz

We previously showed that, although cold-induced thermoregulation is attenuated in 26-mo-old male Fischer 344 (F344) rats, not all rats this age exhibit the same degree of cold-exposed hypothermia or diminished brown adipose tissue nonshivering thermogenic capacity. Examination of this heterogeneity suggested the hypothesis that it was associated with a difference in the physiological state between aged rats that were maintaining stable body weight versus those showing the rapid weight loss often occurring near the end of the rat's natural life span. To test this, we acutely exposed male F344 rats to cold (4 h at 6 degrees C) beginning at 24 mo of age. This exposure was weekly for the first 2 wk and then on alternate weeks as long as the rat's body weight was stable. If body weight progressively declined for 3-5 consecutive days, the rat's response to the acute cold exposure was again measured, as was that of two additional rats not displaying this rapid loss in body weight. If body temperature decreased during the cold exposure to intraperitoneal temperatures < or = 32.5 degrees C, the rat was killed with pentobarbital sodium and interscapular brown adipose tissue was removed. One of the age-matched controls was also killed at this time. The age at which body weight showed a spontaneous rapid decline ranged from 24.5 to 29 mos. All eight rats displaying spontaneous rapid weight loss had significant hypothermia during the acute cold exposure, whereas none of the eight weight-stable rats did. The development of hypothermia in the spontaneous rapid weight loss group was not, in general, observed before their weight loss. The weight loss and hypothermia were associated with lower levels of brown fat uncoupling protein and significant changes in body fat and protein. These data suggest that the development of senescence-related hypothermia occurs rapidly and is not a simple function of chronological age or the median life span of the animals. Furthermore, these data imply that the rate of aging in terms of maintenance of thermoregulatory homeostasis has both a gradual and rapid component, the latter being associated with a different physiological state than the former.


2003 ◽  
Vol 81 (7) ◽  
pp. 747-751 ◽  
Author(s):  
Alessio Sullo ◽  
Guglielmo Brizzi ◽  
Nicola Maffulli

Serotonin (5-HT) and thyroid hormones are part of a complex system modulating eating behaviour and energy expenditure. 5'-Deiodinase (5'-D) converts the relatively inactive thyroxine (T4) to triiodothyronine (T3), and its activity is an indirect measure of T3 production in peripheral tissues, particularly in the brain, intrascapular brown adipose tissue (IBAT), heart, liver, and kidney. We evaluated the effect of 5-HT on 5'-D activity during basal conditions and after short (30 min) cold exposure (thyroid stimulating hormone stimulation test, TST). 5'-D activity was assessed in the liver, heart, brain, kidney, and IBAT. TST increases 5'-D activity in the brain, heart, and IBAT and decreases it in kidney, leaving it unchanged in the liver. 5-HT alone did not modify 5'-D activity in the organs under study but decreased it in the IBAT, heart, and brain when injected before the TST was administered. Our results confirm the important role of 5-HT in thermoregulation, given its peripheral site of action, in modulating heat production controlling intracellular T3 production. These effects are more evident when heat production is upregulated during cold exposure in organs containing type II 5'-D, such as the brain, heart, and IBAT, which are able to modify their function during conditions that alter energy balance. In conclusion, 5-HT may also act peripherally directly on the thyroid and organs containing type II 5'-D, thus controlling energy expenditure through heat production.Key words: serotonin, deiodinase activity, thyroid hormone, brown adipose tissue, thermogenesis, rat organs.


2008 ◽  
Vol 294 (4) ◽  
pp. E688-E697 ◽  
Author(s):  
G. Medina-Gomez ◽  
R. M. Calvo ◽  
M.-J. Obregon

Triiodothyroacetic acid (TRIAC) is a physiological product of triiodothyronine (T3) metabolism, with high affinity for T3 nuclear receptors. Its interest stems from its potential thermogenic effects. Thus this work aimed 1) to clarify these thermogenic effects mediated by TRIAC vs. T3 in vivo and 2) to determine whether they occurred predominantly in adipose tissues. To examine this, control rats were infused with equimolar T3 or TRIAC doses (0.8 or 4 nmol·100 g body wt−1·day−1) or exposed for 48 h to cold. Both T3 doses and only the highest TRIAC dose inhibited plasma and pituitary thyroid-stimulating hormone (TSH) and thyroxine (T4) in plasma and tissues. Interestingly, the lower TRIAC dose marginally inhibited plasma T4. T3 infusion increased plasma and tissue T3 in a tissue-specific manner. The highest TRIAC dose increased TRIAC concentrations in plasma and tissues, decreasing plasma T3. TRIAC concentrations in tissues were <10% those of T3. Under cold exposure or high T3 doses, TRIAC increased only in white adipose tissue (WAT). Remarkably, only the lower TRIAC dose activated thermogenesis, inducing ectopic uncoupling protein (UCP)-1 expression in WAT and maximal increases in UCP-1, UCP-2, and lipoprotein lipase (LPL) expression in brown adipose tissue (BAT), inhibiting UCP-2 in muscle and LPL in WAT. TRIAC, T3, and cold exposure inhibited leptin secretion and mRNA in WAT. In summary, TRIAC, at low doses, induces thermogenic effects in adipose tissues without concomitant inhibition of TSH or hypothyroxinemia, suggesting a specific role regulating energy balance. This selective effect of TRIAC in adipose tissues might be considered a potential tool to increase energy metabolism.


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