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Lyons SA, McClelland GB. Highland deer mice support increased thermogenesis in response to chronic cold hypoxia by shifting uptake of circulating fatty acids from muscles to brown adipose tissue. J Exp Biol 2024; 227:jeb247340. [PMID: 38506250 PMCID: PMC11057874 DOI: 10.1242/jeb.247340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 03/14/2024] [Indexed: 03/21/2024]
Abstract
During maximal cold challenge (cold-induced V̇O2,max) in hypoxia, highland deer mice (Peromyscus maniculatus) show higher rates of circulatory fatty acid delivery compared with lowland deer mice. Fatty acid delivery also increases with acclimation to cold hypoxia (CH) and probably plays a major role in supporting the high rates of thermogenesis observed in highland deer mice. However, it is unknown which tissues take up these fatty acids and their relative contribution to thermogenesis. The goal of this study was to determine the uptake of circulating fatty acids into 24 different tissues during hypoxic cold-induced V̇O2,max, by using [1-14C]2-bromopalmitic acid. To uncover evolved and environment-induced changes in fatty acid uptake, we compared lab-born and -raised highland and lowland deer mice, acclimated to either thermoneutral (30°C, 21 kPa O2) or CH (5°C, 12 kPa O2) conditions. During hypoxic cold-induced V̇O2,max, CH-acclimated highlanders decreased muscle fatty acid uptake and increased uptake into brown adipose tissue (BAT) relative to thermoneutral highlanders, a response that was absent in lowlanders. CH acclimation was also associated with increased activities of enzymes citrate synthase and β-hydroxyacyl-CoA dehydrogenase in the BAT of highlanders, and higher levels of fatty acid translocase CD36 (FAT/CD36) in both populations. This is the first study to show that cold-induced fatty acid uptake is distributed across a wide range of tissues. Highland deer mice show plasticity in this fatty acid distribution in response to chronic cold hypoxia, and combined with higher rates of tissue delivery, this contributes to their survival in the cold high alpine environment.
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Affiliation(s)
- Sulayman A. Lyons
- Department of Biology, McMaster University, Hamilton, ON, Canada, L8S 4K1
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2
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Alemany M. The Metabolic Syndrome, a Human Disease. Int J Mol Sci 2024; 25:2251. [PMID: 38396928 PMCID: PMC10888680 DOI: 10.3390/ijms25042251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 01/29/2024] [Accepted: 01/31/2024] [Indexed: 02/25/2024] Open
Abstract
This review focuses on the question of metabolic syndrome (MS) being a complex, but essentially monophyletic, galaxy of associated diseases/disorders, or just a syndrome of related but rather independent pathologies. The human nature of MS (its exceptionality in Nature and its close interdependence with human action and evolution) is presented and discussed. The text also describes the close interdependence of its components, with special emphasis on the description of their interrelations (including their syndromic development and recruitment), as well as their consequences upon energy handling and partition. The main theories on MS's origin and development are presented in relation to hepatic steatosis, type 2 diabetes, and obesity, but encompass most of the MS components described so far. The differential effects of sex and its biological consequences are considered under the light of human social needs and evolution, which are also directly related to MS epidemiology, severity, and relations with senescence. The triggering and maintenance factors of MS are discussed, with especial emphasis on inflammation, a complex process affecting different levels of organization and which is a critical element for MS development. Inflammation is also related to the operation of connective tissue (including the adipose organ) and the widely studied and acknowledged influence of diet. The role of diet composition, including the transcendence of the anaplerotic maintenance of the Krebs cycle from dietary amino acid supply (and its timing), is developed in the context of testosterone and β-estradiol control of the insulin-glycaemia hepatic core system of carbohydrate-triacylglycerol energy handling. The high probability of MS acting as a unique complex biological control system (essentially monophyletic) is presented, together with additional perspectives/considerations on the treatment of this 'very' human disease.
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Affiliation(s)
- Marià Alemany
- Faculty of Biology, Universitat de Barcelona, 08028 Barcelona, Catalonia, Spain
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3
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Lyons SA, McClelland GB. Thermogenesis is supported by high rates of circulatory fatty acid and triglyceride delivery in highland deer mice. J Exp Biol 2022; 225:275398. [PMID: 35552735 DOI: 10.1242/jeb.244080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 05/06/2022] [Indexed: 10/18/2022]
Abstract
Highland native deer mice (Peromyscus maniculatus) have greater rates of lipid oxidation during maximal cold challenge in hypoxia (hypoxic cold-induced V˙O2max) compared to their lowland conspecifics. Lipid oxidation is also increased in deer mice acclimated to simulated high altitude (cold hypoxia), regardless of altitude ancestry. The underlying lipid metabolic pathway traits responsible for sustaining maximal thermogenic demand in deer mice is currently unknown. The objective of this study was to characterize key steps in the lipid oxidation pathway in highland and lowland deer mice acclimated to control (23oC, 21kPa O2) or cold hypoxic (5oC, 12kPa O2) conditions. We hypothesized that capacities for lipid delivery and tissue uptake will be greater in highlanders and further increase with cold hypoxia acclimation. With the transition from rest to hypoxic cold-induced V˙O2max, both highland and lowland deer mice showed increased plasma glycerol concentrations and fatty acid availability. Interestingly, cold hypoxia acclimation led to increased plasma triglyceride concentrations at cold-induced V˙O2max, but only in highlanders. Highlanders also had significantly greater delivery rates of circulatory free fatty acids and triglycerides due to higher plasma flow rates at cold-induced V˙O2max. We found no population or acclimation differences in fatty acid translocase (FAT/CD36) abundance in the gastrocnemius or brown adipose tissue, suggesting fatty acid uptake across membranes is not limiting during thermogenesis. Our data indicate that circulatory lipid delivery plays a major role in supporting the high thermogenic rates observed in highland versus lowland deer mice.
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Affiliation(s)
- Sulayman A Lyons
- Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | - Grant B McClelland
- Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada
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Manfredi LH. Overheating or overcooling: heat transfer in the spot to fight against the pandemic obesity. Rev Endocr Metab Disord 2021; 22:665-680. [PMID: 33000381 DOI: 10.1007/s11154-020-09596-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/17/2020] [Indexed: 12/25/2022]
Abstract
The prevalence of obesity has nearly doubled worldwide over the past three and a half decades, reaching pandemic status. Obesity is associated with decreased life expectancy and with an increased risk of metabolic, cardiovascular, nervous system diseases. Hence, understanding the mechanisms involved in the onset and development of obesity is mandatory to promote planned health actions to revert this scenario. In this review, common aspects of cold exposure, a process of heat generation, and exercise, a process of heat dissipation, will be discussed as two opposite mechanisms of obesity, which can be oversimplified as caloric conservation. A common road between heat generation and dissipation is the mobilization of Free Faty Acids (FFA) and Carbohydrates (CHO). An increase in energy expenditure (immediate effect) and molecular/metabolic adaptations (chronic effect) are responses that depend on SNS activity in both conditions of heat transfer. This cycle of using and removing FFA and CHO from blood either for heat or force generation disrupt the key concept of obesity: energy accumulation. Despite efforts in making the anti-obesity pill, maybe it is time to consider that the world's population is living at thermoneutrality since temperature-controlled places and the lack of exercise are favoring caloric accumulation.
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Affiliation(s)
- Leandro Henrique Manfredi
- Graduate Program in Biomedical Sciences, Federal University of Fronteira Sul, Chapecó, Santa Catarina, Brazil.
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Lyons SA, Tate KB, Welch KC, McClelland GB. Lipid oxidation during thermogenesis in high-altitude deer mice ( Peromyscus maniculatus). Am J Physiol Regul Integr Comp Physiol 2021; 320:R735-R746. [PMID: 33729020 DOI: 10.1152/ajpregu.00266.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
When at their maximum thermogenic capacity (cold-induced V̇o2max), small endotherms reach levels of aerobic metabolism as high, or even higher, than running V̇o2max. How these high rates of thermogenesis are supported by substrate oxidation is currently unclear. The appropriate utilization of metabolic fuels that could sustain thermogenesis over extended periods may be important for survival in cold environments, like high altitude. Previous studies show that high capacities for lipid use in high-altitude deer mice may have evolved in concert with greater thermogenic capacities. The purpose of this study was to determine how lipid utilization at both moderate and maximal thermogenic intensities may differ in high- and low-altitude deer mice, and strictly low-altitude white-footed mice. We also examined the phenotypic plasticity of lipid use after acclimation to cold hypoxia (CH), conditions simulating high altitude. We found that lipids were the primary fuel supporting both moderate and maximal rates of thermogenesis in both species of mice. Lipid oxidation increased threefold in mice from 30°C to 0°C, consistent with increases in oxidation of [13C]palmitic acid. CH acclimation led to an increase in [13C]palmitic acid oxidation at 30°C but did not affect total lipid oxidation. Lipid oxidation rates at cold-induced V̇o2max were two- to fourfold those at 0°C and increased further after CH acclimation, especially in high-altitude deer mice. These are the highest mass-specific lipid oxidation rates observed in any land mammal. Uncovering the mechanisms that allow for these high rates of oxidation will aid our understanding of the regulation of lipid metabolism.
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Affiliation(s)
- Sulayman A Lyons
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Kevin B Tate
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Kenneth C Welch
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
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Dawson NJ, Alza L, Nandal G, Scott GR, McCracken KG. Convergent changes in muscle metabolism depend on duration of high-altitude ancestry across Andean waterfowl. eLife 2020; 9:e56259. [PMID: 32729830 PMCID: PMC7494360 DOI: 10.7554/elife.56259] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 07/23/2020] [Indexed: 01/07/2023] Open
Abstract
High-altitude environments require that animals meet the metabolic O2 demands for locomotion and thermogenesis in O2-thin air, but the degree to which convergent metabolic changes have arisen across independent high-altitude lineages or the speed at which such changes arise is unclear. We examined seven high-altitude waterfowl that have inhabited the Andes (3812-4806 m elevation) over varying evolutionary time scales, to elucidate changes in biochemical pathways of energy metabolism in flight muscle relative to low-altitude sister taxa. Convergent changes across high-altitude taxa included increased hydroxyacyl-coA dehydrogenase and succinate dehydrogenase activities, decreased lactate dehydrogenase, pyruvate kinase, creatine kinase, and cytochrome c oxidase activities, and increased myoglobin content. ATP synthase activity increased in only the longest established high-altitude taxa, whereas hexokinase activity increased in only newly established taxa. Therefore, changes in pathways of lipid oxidation, glycolysis, and mitochondrial oxidative phosphorylation are common strategies to cope with high-altitude hypoxia, but some changes require longer evolutionary time to arise.
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Affiliation(s)
- Neal J Dawson
- Department of Biology, McMaster UniversityHamiltonCanada
- Department of Biology University of MiamiCoral GablesUnited States
| | - Luis Alza
- Department of Biology University of MiamiCoral GablesUnited States
- University of Alaska Museum and Institute of Arctic Biology, University of Alaska FairbanksFairbanksUnited States
- Centro de Ornitología y Biodiversidad - CORBIDILimaPeru
| | | | - Graham R Scott
- Department of Biology, McMaster UniversityHamiltonCanada
| | - Kevin G McCracken
- Department of Biology University of MiamiCoral GablesUnited States
- University of Alaska Museum and Institute of Arctic Biology, University of Alaska FairbanksFairbanksUnited States
- Centro de Ornitología y Biodiversidad - CORBIDILimaPeru
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Sciences, University of MiamiMiamiUnited States
- Human Genetics and Genomics, Hussman Institute for Human Genomics, University of Miami Miller School of MedicineMiamiUnited States
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Havighorst A, Zhang Y, Farmaki E, Kaza V, Chatzistamou I, Kiaris H. Differential regulation of the unfolded protein response in outbred deer mice and susceptibility to metabolic disease. Dis Model Mech 2019; 12:dmm.037242. [PMID: 30733237 PMCID: PMC6398494 DOI: 10.1242/dmm.037242] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 01/28/2019] [Indexed: 01/10/2023] Open
Abstract
Endoplasmic reticulum (ER) stress has been causatively linked to the onset of various pathologies. However, whether and how inherent variations in the resulting unfolded protein response (UPR) affect predisposition to ER-stress-associated metabolic conditions remains to be established. By using genetically diverse deer mice (Peromyscus maniculatus) as a model, we show that the profile of tunicamycin-induced UPR in fibroblasts isolated at puberty varies between individuals and predicts deregulation of lipid metabolism and diet-induced hepatic steatosis later in life. Among the different UPR targets tested, CHOP (also known as Ddit3) more consistently predicted elevated plasma cholesterol and hepatic steatosis. Compared with baseline levels or inducibility, the maximal intensity of the UPR following stimulation best predicts the onset of pathology. Differences in the expression profile of the UPR recorded in cells from different populations of deer mice correlate with the varying response to ER stress in altitude adaptation. Our data suggest that the response to ER stress in cultured cells varies among individuals, and its profile early in life might predict the onset of ER-stress-associated disease in the elderly. This article has an associated First Person interview with the first author of the paper. Summary: By using genetically diverse deer mice, we show that the expression of different chaperones is highly coordinated in individual animals and its profile predicts the onset of metabolic pathology.
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Affiliation(s)
- Amanda Havighorst
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, SC 29208-3402, USA
| | - Youwen Zhang
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, SC 29208-3402, USA
| | - Elena Farmaki
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, SC 29208-3402, USA
| | - Vimala Kaza
- Peromyscus Genetic Stock Center, University of South Carolina, Columbia, SC 29208-3402, USA
| | - Ioulia Chatzistamou
- Department of Pathology, Microbiology and Immunology, School of Medicine, University of South Carolina, Columbia, SC 29208-3402, USA
| | - Hippokratis Kiaris
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, SC 29208-3402, USA .,Peromyscus Genetic Stock Center, University of South Carolina, Columbia, SC 29208-3402, USA
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Guilherme A, Pedersen DJ, Henriques F, Bedard AH, Henchey E, Kelly M, Morgan DA, Rahmouni K, Czech MP. Neuronal modulation of brown adipose activity through perturbation of white adipocyte lipogenesis. Mol Metab 2018; 16:116-125. [PMID: 30005879 PMCID: PMC6157614 DOI: 10.1016/j.molmet.2018.06.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 06/13/2018] [Accepted: 06/25/2018] [Indexed: 01/14/2023] Open
Abstract
OBJECTIVE Crosstalk between adipocytes and local neurons may be an important regulatory mechanism to control energy homeostasis. We previously reported that perturbation of adipocyte de novo lipogenesis (DNL) by deletion of fatty acid synthase (FASN) expands sympathetic neurons within white adipose tissue (WAT) and stimulates the appearance of "beige" adipocytes. Here we tested whether WAT DNL activity can also influence neuronal regulation and thermogenesis in brown adipose tissue (BAT). METHODS AND RESULTS Induced deletion of FASN in all adipocytes in mature mice (iAdFASNKO) enhanced sympathetic innervation and neuronal activity as well as UCP1 expression in both WAT and BAT. This increased sympathetic innervation could be observed at both 22 °C and 30 °C, indicating it is not a response to heat loss but rather adipocyte signaling. In contrast, selective ablation of FASN in brown adipocytes of mice (iUCP1FASNKO) failed to modulate sympathetic innervation and the thermogenic program in BAT. Surprisingly, DNL in brown adipocytes was also dispensable in maintaining euthermia when UCP1FASNKO mice were cold-exposed. CONCLUSION These results indicate that DNL in white adipocytes influences long distance signaling to BAT, which can modify BAT sympathetic innervation and expression of genes involved in thermogenesis.
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Affiliation(s)
- Adilson Guilherme
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - David J Pedersen
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Felipe Henriques
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Alexander H Bedard
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Elizabeth Henchey
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Mark Kelly
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Donald A Morgan
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, 52242, USA
| | - Kamal Rahmouni
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, 52242, USA
| | - Michael P Czech
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, 01605, USA.
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9
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McClelland GB, Scott GR. Evolved Mechanisms of Aerobic Performance and Hypoxia Resistance in High-Altitude Natives. Annu Rev Physiol 2018; 81:561-583. [PMID: 30256727 DOI: 10.1146/annurev-physiol-021317-121527] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Comparative physiology studies of high-altitude species provide an exceptional opportunity to understand naturally evolved mechanisms of hypoxia resistance. Aerobic capacity (VO2max) is a critical performance trait under positive selection in some high-altitude taxa, and several high-altitude natives have evolved to resist the depressive effects of hypoxia on VO2max. This is associated with enhanced flux capacity through the O2 transport cascade and attenuation of the maladaptive responses to chronic hypoxia that can impair O2 transport. Some highlanders exhibit elevated rates of carbohydrate oxidation during exercise, taking advantage of its high ATP yield per mole of O2. Certain highland native animals have also evolved more oxidative muscles and can sustain high rates of lipid oxidation to support thermogenesis. The underlying mechanisms include regulatory adjustments of metabolic pathways and to gene expression networks. Therefore, the evolution of hypoxia resistance in high-altitude natives involves integrated functional changes in the pathways for O2 and substrate delivery and utilization by mitochondria.
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Affiliation(s)
- Grant B McClelland
- Department of Biology, McMaster University, Hamilton, Ontario L8S 4K1, Canada;
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, Ontario L8S 4K1, Canada;
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McClelland GB, Lyons SA, Robertson CE. Fuel Use in Mammals: Conserved Patterns and Evolved Strategies for Aerobic Locomotion and Thermogenesis. Integr Comp Biol 2018; 57:231-239. [PMID: 28859408 DOI: 10.1093/icb/icx075] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
SYNOPSIS Effective aerobic locomotion depends on adequate delivery of oxygen and an appropriate allocation of metabolic substrates. The use of metabolic substrates during exercise follows a predictive pattern of lipid and carbohydrate oxidation that is similar in lowland native cursorial mammals. We have found that in two highland lineages of mice (Phyllotis and Peromyscus) the fuel use pattern is shifted to a greater reliance on carbohydrates compared to their lowland conspecifics and congenerics. However, there is variation between lineages in the importance of phenotypic plasticity in the expression of this metabolic phenotype. Moreover, this metabolic phenotype is independent of running aerobic capacity and can also be independent of thermogenic capacity. For example, wild-caught mice from a highland population of deer mice (Peromyscus maniculatus) housed in warm normoxic laboratory conditions maintain higher maximum cold-induced oxygen consumption in acute hypoxia than lowland congenerics, but shivering and non-shivering thermogenesis is supported by high rates of lipid oxidation. This is reflected in the consistently higher activities of oxidative and fatty acid oxidation enzymes in the gastrocnemius of highland deer mice compared to lowlanders, which are resistant to hypoxia acclimation. While a fixed trait in muscle aerobic capacity may reflect the pervasive and unremitting low PO2 at high altitudes, muscle capacities for substrate oxidation may be more flexible to match appropriate substrate use with changing energetic demands. How shivering thermogenesis and locomotion potentially interact in the matching of muscle metabolic capacities to appropriate substrate use is unclear. Perhaps it is possible that shivering serves as "training" to ensure muscles have the capacity to support locomotion or visa-versa.
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Affiliation(s)
- Grant B McClelland
- Department of Biology, McMaster University, Hamilton, ON, Canada L8S 4K1
| | - Sulayman A Lyons
- Department of Biology, McMaster University, Hamilton, ON, Canada L8S 4K1
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Machado FSM, Zhang Z, Su Y, de Goede P, Jansen R, Foppen E, Coimbra CC, Kalsbeek A. Time-of-Day Effects on Metabolic and Clock-Related Adjustments to Cold. Front Endocrinol (Lausanne) 2018; 9:199. [PMID: 29755411 PMCID: PMC5932155 DOI: 10.3389/fendo.2018.00199] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 04/10/2018] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Daily cyclic changes in environmental conditions are key signals for anticipatory and adaptive adjustments of most living species, including mammals. Lower ambient temperature stimulates the thermogenic activity of brown adipose tissue (BAT) and skeletal muscle. Given that the molecular components of the endogenous biological clock interact with thermal and metabolic mechanisms directly involved in the defense of body temperature, the present study evaluated the differential homeostatic responses to a cold stimulus at distinct time-windows of the light/dark-cycle. METHODS Male Wistar rats were subjected to a single episode of 3 h cold ambient temperature (4°C) at one of 6 time-points starting at Zeitgeber Times 3, 7, 11, 15, 19, and 23. Metabolic rate, core body temperature, locomotor activity (LA), feeding, and drinking behaviors were recorded during control and cold conditions at each time-point. Immediately after the stimulus, rats were euthanized and both the soleus and BAT were collected for real-time PCR. RESULTS During the light phase (i.e., inactive phase), cold exposure resulted in a slight hyperthermia (p < 0.001). Light phase cold exposure also increased metabolic rate and LA (p < 0.001). In addition, the prevalence of fat oxidative metabolism was attenuated during the inactive phase (p < 0.001). These metabolic changes were accompanied by time-of-day and tissue-specific changes in core clock gene expression, such as DBP (p < 0.0001) and REV-ERBα (p < 0.01) in the BAT and CLOCK (p < 0.05), PER2 (p < 0.05), CRY1 (p < 0.05), CRY2 (p < 0.01), and REV-ERBα (p < 0.05) in the soleus skeletal muscle. Moreover, genes involved in substrate oxidation and thermogenesis were affected in a time-of-day and tissue-specific manner by cold exposure. CONCLUSION The time-of-day modulation of substrate mobilization and oxidation during cold exposure provides a clear example of the circadian modulation of physiological and metabolic responses. Interestingly, after cold exposure, time-of-day mostly affected circadian clock gene expression in the soleus muscle, despite comparable changes in LA over the light-dark-cycle. The current findings add further evidence for tissue-specific actions of the internal clock in different peripheral organs such as skeletal muscle and BAT.
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Affiliation(s)
- Frederico Sander Mansur Machado
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Amsterdam, Netherlands
- Department of Physiology and Biophysics, Biological Sciences Institute, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Zhi Zhang
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Amsterdam, Netherlands
- Laboratory of Endocrinology, Department of Clinical Chemistry, Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands
| | - Yan Su
- Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Amsterdam, Netherlands
- Laboratory of Endocrinology, Department of Clinical Chemistry, Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands
| | - Paul de Goede
- Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Amsterdam, Netherlands
- Laboratory of Endocrinology, Department of Clinical Chemistry, Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands
| | - Remi Jansen
- Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Amsterdam, Netherlands
- Laboratory of Endocrinology, Department of Clinical Chemistry, Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands
| | - Ewout Foppen
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Department of Clinical Chemistry, Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands
| | - Cândido Celso Coimbra
- Department of Physiology and Biophysics, Biological Sciences Institute, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Andries Kalsbeek
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Amsterdam, Netherlands
- Laboratory of Endocrinology, Department of Clinical Chemistry, Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands
- *Correspondence: Andries Kalsbeek,
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12
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Lau DS, Connaty AD, Mahalingam S, Wall N, Cheviron ZA, Storz JF, Scott GR, McClelland GB. Acclimation to hypoxia increases carbohydrate use during exercise in high-altitude deer mice. Am J Physiol Regul Integr Comp Physiol 2017; 312:R400-R411. [PMID: 28077391 DOI: 10.1152/ajpregu.00365.2016] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 12/13/2016] [Accepted: 01/05/2017] [Indexed: 12/24/2022]
Abstract
The low O2 experienced at high altitude is a significant challenge to effective aerobic locomotion, as it requires sustained tissue O2 delivery in addition to the appropriate allocation of metabolic substrates. Here, we tested whether high- and low-altitude deer mice (Peromyscus maniculatus) have evolved different acclimation responses to hypoxia with respect to muscle metabolism and fuel use during submaximal exercise. Using F1 generation high- and low-altitude deer mice that were born and raised in common conditions, we assessed 1) fuel use during exercise, 2) metabolic enzyme activities, and 3) gene expression for key transporters and enzymes in the gastrocnemius. After hypoxia acclimation, highland mice showed a significant increase in carbohydrate oxidation and higher relative reliance on this fuel during exercise at 75% maximal O2 consumption. Compared with lowland mice, highland mice had consistently higher activities of oxidative and fatty acid oxidation enzymes in the gastrocnemius. In contrast, only after hypoxia acclimation did activities of hexokinase increase significantly in the muscle of highland mice to levels greater than lowland mice. Highland mice also responded to acclimation with increases in muscle gene expression for hexokinase 1 and 2 genes, whereas both populations increased mRNA expression for glucose transporters. Changes in skeletal muscle with acclimation suggest that highland mice had an increased capacity for the uptake and oxidation of circulatory glucose. Our results demonstrate that highland mice have evolved a distinct mode of hypoxia acclimation that involves an increase in carbohydrate use during exercise.
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Affiliation(s)
- Daphne S Lau
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Alex D Connaty
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Sajeni Mahalingam
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Nastashya Wall
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Zachary A Cheviron
- Division of Biological Sciences, University of Montana, Missoula, Montana; and
| | - Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
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Stager M, Swanson DL, Cheviron ZA. Regulatory mechanisms of metabolic flexibility in the dark-eyed junco (Junco hyemalis). J Exp Biol 2015; 218:767-77. [DOI: 10.1242/jeb.113472] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
ABSTRACT
Small temperate birds reversibly modify their aerobic performance to maintain thermoregulatory homeostasis under seasonally changing environmental conditions and these physiological adjustments may be attributable to changes in the expression of genes in the underlying regulatory networks. Here, we report the results of an experimental procedure designed to gain insight into the fundamental mechanisms of metabolic flexibility in the dark-eyed junco (Junco hyemalis). We combined genomic transcriptional profiles with measures of metabolic enzyme activities and whole-animal thermogenic performance from juncos exposed to four 6-week acclimation treatments that varied in temperature (cold, 3°C; warm, 24°C) and photoperiod (short day, 8 h light:16 h dark; long day, 16 h light:8 h dark). Cold-acclimated birds increased thermogenic capacity compared with warm-acclimated birds, and this enhanced performance was associated with upregulation of genes involved in muscle hypertrophy, angiogenesis, and lipid transport and oxidation, as well as with catabolic enzyme activities. These physiological changes occurred over ecologically relevant timescales, suggesting that birds make regulatory adjustments to interacting, hierarchical pathways in order to seasonally enhance thermogenic capacity.
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Affiliation(s)
- Maria Stager
- Department of Animal Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - David L. Swanson
- Department of Biology, University of South Dakota, Vermillion, SD 57069, USA
| | - Zachary A. Cheviron
- Department of Animal Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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Mottillo EP, Balasubramanian P, Lee YH, Weng C, Kershaw EE, Granneman JG. Coupling of lipolysis and de novo lipogenesis in brown, beige, and white adipose tissues during chronic β3-adrenergic receptor activation. J Lipid Res 2014; 55:2276-86. [PMID: 25193997 DOI: 10.1194/jlr.m050005] [Citation(s) in RCA: 204] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Chronic activation of β3-adrenergic receptors (β3-ARs) expands the catabolic activity of both brown and white adipose tissue by engaging uncoupling protein 1 (UCP1)-dependent and UCP1-independent processes. The present work examined de novo lipogenesis (DNL) and TG/glycerol dynamics in classic brown, subcutaneous "beige," and classic white adipose tissues during sustained β3-AR activation by CL 316,243 (CL) and also addressed the contribution of TG hydrolysis to these dynamics. CL treatment for 7 days dramatically increased DNL and TG turnover similarly in all adipose depots, despite great differences in UCP1 abundance. Increased lipid turnover was accompanied by the simultaneous upregulation of genes involved in FAS, glycerol metabolism, and FA oxidation. Inducible, adipocyte-specific deletion of adipose TG lipase (ATGL), the rate-limiting enzyme for lipolysis, demonstrates that TG hydrolysis is required for CL-induced increases in DNL, TG turnover, and mitochondrial electron transport in all depots. Interestingly, the effect of ATGL deletion on induction of specific genes involved in FA oxidation and synthesis varied among fat depots. Overall, these studies indicate that FAS and FA oxidation are tightly coupled in adipose tissues during chronic adrenergic activation, and this effect critically depends on the activity of adipocyte ATGL.
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Affiliation(s)
- Emilio P Mottillo
- Center for Integrative Metabolic and Endocrine Research, Wayne State University School of Medicine, Detroit, MI
| | - Priya Balasubramanian
- Center for Integrative Metabolic and Endocrine Research, Wayne State University School of Medicine, Detroit, MI
| | - Yun-Hee Lee
- Center for Integrative Metabolic and Endocrine Research, Wayne State University School of Medicine, Detroit, MI
| | - Changren Weng
- Center for Integrative Metabolic and Endocrine Research, Wayne State University School of Medicine, Detroit, MI
| | - Erin E Kershaw
- Division of Endocrinology, Department of Medicine, University of Pittsburgh, Pittsburgh, PA
| | - James G Granneman
- Center for Integrative Metabolic and Endocrine Research, Wayne State University School of Medicine, Detroit, MI Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI
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Vucetic M, Stancic A, Otasevic V, Jankovic A, Korac A, Markelic M, Velickovic K, Golic I, Buzadzic B, Storey KB, Korac B. The impact of cold acclimation and hibernation on antioxidant defenses in the ground squirrel (Spermophilus citellus): an update. Free Radic Biol Med 2013; 65:916-924. [PMID: 24013092 DOI: 10.1016/j.freeradbiomed.2013.08.188] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 08/14/2013] [Accepted: 08/28/2013] [Indexed: 01/07/2023]
Abstract
Any alteration in oxidative metabolism is coupled with a corresponding response by an antioxidant defense (AD) in appropriate subcellular compartments. Seasonal hibernators pass through circannual metabolic adaptations that allow them to either maintain euthermy (cold acclimation) or enter winter torpor with body temperature falling to low values. The present study aimed to investigate the corresponding pattern of AD enzyme protein expressions associated with these strategies in the main tissues involved in whole animal energy homeostasis: brown and white adipose tissues (BAT and WAT, respectively), liver, and skeletal muscle. European ground squirrels (Spermophilus citellus) were exposed to low temperature (4 ± 1 °C) and then divided into two groups: (1) animals fell into torpor (hibernating group) and (2) animals stayed active and euthermic for 1, 3, 7, 12, or 21 days (cold-exposed group). We examined the effects of cold acclimation and hibernation on the tissue-dependent protein expression of four enzymes which catalyze the two-step detoxification of superoxide to water: superoxide dismutase 1 and 2 (SOD 1 and 2), catalase (CAT), and glutathione peroxidase (GSH-Px). The results showed that hibernation induced an increase of AD enzyme protein expressions in BAT and skeletal muscle. However, AD enzyme contents in liver were largely unaffected during torpor. Under these conditions, different WAT depots responded by elevating the amounts of specific enzymes, as follows: SOD 1 in retroperitoneal WAT, GSH-Px in gonadal WAT, and CAT in subcutaneous WAT. Similar perturbations of AD enzymes contents were seen in all tissues during cold acclimation, often in a time-dependent manner. It can be concluded that BAT and muscle AD capacity undergo the most dramatic changes during both cold acclimation and hibernation, while liver is relatively unaffected by either condition. Additionally, this study provides a basis for further metabolic study that will illuminate the causes of these tissue-specific AD responses, particularly the novel finding of distinct responses by different WAT depots in hibernators.
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Affiliation(s)
- Milica Vucetic
- University of Belgrade, Institute for Biological Research "Sinisa Stankovic," Department of Physiology, Bulevar despota Stefana 142, 11060 Belgrade, Serbia
| | - Ana Stancic
- University of Belgrade, Institute for Biological Research "Sinisa Stankovic," Department of Physiology, Bulevar despota Stefana 142, 11060 Belgrade, Serbia
| | - Vesna Otasevic
- University of Belgrade, Institute for Biological Research "Sinisa Stankovic," Department of Physiology, Bulevar despota Stefana 142, 11060 Belgrade, Serbia
| | - Aleksandra Jankovic
- University of Belgrade, Institute for Biological Research "Sinisa Stankovic," Department of Physiology, Bulevar despota Stefana 142, 11060 Belgrade, Serbia
| | - Aleksandra Korac
- University of Belgrade, Faculty of Biology, Center for Electron Microscopy, Belgrade, Serbia
| | - Milica Markelic
- University of Belgrade, Faculty of Biology, Center for Electron Microscopy, Belgrade, Serbia
| | - Ksenija Velickovic
- University of Belgrade, Faculty of Biology, Center for Electron Microscopy, Belgrade, Serbia
| | - Igor Golic
- University of Belgrade, Faculty of Biology, Center for Electron Microscopy, Belgrade, Serbia
| | - Biljana Buzadzic
- University of Belgrade, Institute for Biological Research "Sinisa Stankovic," Department of Physiology, Bulevar despota Stefana 142, 11060 Belgrade, Serbia
| | - Kenneth B Storey
- Carleton University, Department of Biology, Ottawa, Ontario, Canada
| | - Bato Korac
- University of Belgrade, Institute for Biological Research "Sinisa Stankovic," Department of Physiology, Bulevar despota Stefana 142, 11060 Belgrade, Serbia.
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Cheviron ZA, Connaty AD, McClelland GB, Storz JF. Functional genomics of adaptation to hypoxic cold-stress in high-altitude deer mice: transcriptomic plasticity and thermogenic performance. Evolution 2013; 68:48-62. [PMID: 24102503 DOI: 10.1111/evo.12257] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 08/16/2013] [Indexed: 12/14/2022]
Abstract
In species that are distributed across steep environmental gradients, adaptive variation in physiological performance may be attributable to transcriptional plasticity in underlying regulatory networks. Here we report the results of common-garden experiments that were designed to elucidate the role of regulatory plasticity in evolutionary adaptation to hypoxic cold-stress in deer mice (Peromyscus maniculatus). We integrated genomic transcriptional profiles with measures of metabolic enzyme activities and whole-animal thermogenic performance under hypoxia in highland (4350 m) and lowland (430 m) mice from three experimental groups: (1) wild-caught mice that were sampled at their native elevations; (2) wild-caught/lab-reared mice that were deacclimated to low-elevation conditions in a common-garden lab environment; and (3) the F(1) progeny of deacclimated mice that were maintained under the same low-elevation common-garden conditions. In each experimental group, highland mice exhibited greater thermogenic capacities than lowland mice, and this enhanced performance was associated with upregulation of transcriptional modules that influence several hierarchical steps in the O(2) cascade, including tissue O(2) diffusion (angiogenesis) and tissue O(2) utilization (metabolic fuel use and cellular oxidative capacity). Most of these performance-related transcriptomic changes occurred over physiological and developmental timescales, suggesting that regulatory plasticity makes important contributions to fitness-related physiological performance in highland deer mice.
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Affiliation(s)
- Zachary A Cheviron
- Department of Animal Biology, University of Illinois, 515 Morrill Hall, 505 S. Goodwin Avenue, Urbana, Illinois, 61801.
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Stancic A, Buzadzic B, Korac A, Otasevic V, Jankovic A, Vucetic M, Markelic M, Velickovic K, Golic I, Korac B. Regulatory role of PGC-1α/PPAR signaling in skeletal muscle metabolic recruitment during cold acclimation. ACTA ACUST UNITED AC 2013; 216:4233-41. [PMID: 23948478 DOI: 10.1242/jeb.089334] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
This study examined the molecular basis of energy-related regulatory mechanisms underlying metabolic recruitment of skeletal muscle during cold acclimation and possible involvement of the l-arginine/nitric oxide-producing pathway. Rats exposed to cold (4±1°C) for periods of 1, 3, 7, 12, 21 and 45 days were divided into three groups: untreated, l-arginine treated and N(ω)-nitro-l-arginine methyl ester (l-NAME) treated. Compared with controls (22±1°C), there was an initial increase in the protein level of 5'-AMP-activated protein kinase α (day 1), followed by an increase in peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) and peroxisome proliferator-activated receptors (PPARs): PPARα and PPARγ from day 1 and PPARδ from day 7 of cold acclimation. Activation of the PGC-1α/PPAR transcription program was accompanied by increased protein expression of the key metabolic enzymes in β-oxidation, the tricarboxylic acid cycle and oxidative phosphorylation, with the exceptions in complex I (no changes) and ATP synthase (decreased at day 1). Cold did not affect hexokinase and GAPDH protein levels, but increased lactate dehydrogenase activity compared with controls (1-45 days). l-arginine sustained, accelerated and/or intensified cold-induced molecular remodeling throughout cold acclimation. l-NAME exerted phase-dependent effects: similar to l-arginine in early cold acclimation and opposite after prolonged cold exposure (from day 21). It seems that upregulation of the PGC-1α/PPAR transcription program early during cold acclimation triggers the molecular recruitment of skeletal muscle underlying the shift to more oxidative metabolism during prolonged cold acclimation. Our results suggest that nitric oxide has a role in maintaining the skeletal muscle oxidative phenotype in late cold acclimation but question its role early in cold acclimation.
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Affiliation(s)
- Ana Stancic
- University of Belgrade, Department of Physiology, Institute for Biological Research 'Sinisa Stankovic', Bulevar despota Stefana 142, 11060 Belgrade, Serbia
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Nault R, Abdul-Fattah H, Mironov GG, Berezovski MV, Moon TW. Assessment of energetic costs of AhR activation by β-naphthoflavone in rainbow trout (Oncorhynchus mykiss) hepatocytes using metabolic flux analysis. Toxicol Appl Pharmacol 2013; 271:86-94. [DOI: 10.1016/j.taap.2013.04.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 03/18/2013] [Accepted: 04/01/2013] [Indexed: 02/01/2023]
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Manfredi LH, Zanon NM, Garófalo MA, Navegantes LCC, Kettelhut IC. Effect of short-term cold exposure on skeletal muscle protein breakdown in rats. J Appl Physiol (1985) 2013; 115:1496-505. [PMID: 23908317 DOI: 10.1152/japplphysiol.00474.2013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Although it is well established that carbohydrate and lipid metabolism are profoundly altered by cold stress, the effects of short-term cold exposure on protein metabolism in skeletal muscle are still poorly understood. Because cold acclimation requires that an organism adjust its metabolic flux, and muscle amino acids may be an important energy source for heat production, we hypothesize that muscle proteolysis is increased and protein synthesis is decreased under such a stress condition. Herein, cold exposure for 24 h decreased rates of protein synthesis and increased overall proteolysis in both soleus and extensor digitorum longus (EDL) muscles, but it did not affect muscle weight. An increase in proteolysis was accompanied by hyperactivity of the ubiquitin-proteasome system (UPS) in both soleus and EDL, and Ca(2+)-dependent proteolysis in EDL. Furthermore, muscles of rats exposed to cold showed increased mRNA and protein levels of atrogin-1 and muscle RING finger enzyme-1 (MuRF1). Additionally, cold stress reduced phosphorylation of Akt and Forkhead box class O1 (FoxO1), a well-known effect that increases FoxO translocation to the nucleus and leads to activation of proteolysis. Plasma insulin levels were lower, whereas catecholamines, corticosterone, and thyroid hormones were higher in cold-exposed rats compared with control rats. The present data provide the first direct evidence that short-term cold exposure for 24 h decreases rates of protein synthesis and increases the UPS and Ca(2+)-dependent proteolytic processes, and increases expression of atrogin-1 and MuRF1 in skeletal muscles of young rats. The activation of atrophy induced by acute cold stress seems to be mediated at least in part through the inactivation of Akt/FoxO signaling and activation of AMP-activated protein kinase.
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Affiliation(s)
- L H Manfredi
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
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Regulatory changes contribute to the adaptive enhancement of thermogenic capacity in high-altitude deer mice. Proc Natl Acad Sci U S A 2012; 109:8635-40. [PMID: 22586089 DOI: 10.1073/pnas.1120523109] [Citation(s) in RCA: 137] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In response to hypoxic stress, many animals compensate for a reduced cellular O(2) supply by suppressing total metabolism, thereby reducing O(2) demand. For small endotherms that are native to high-altitude environments, this is not always a viable strategy, as the capacity for sustained aerobic thermogenesis is critical for survival during periods of prolonged cold stress. For example, survivorship studies of deer mice (Peromyscus maniculatus) have demonstrated that thermogenic capacity is under strong directional selection at high altitude. Here, we integrate measures of whole-organism thermogenic performance with measures of metabolic enzyme activities and genomic transcriptional profiles to examine the mechanistic underpinnings of adaptive variation in this complex trait in deer mice that are native to different elevations. We demonstrate that highland deer mice have an enhanced thermogenic capacity under hypoxia compared with lowland conspecifics and a closely related lowland species, Peromyscus leucopus. Our findings suggest that the enhanced thermogenic performance of highland deer mice is largely attributable to an increased capacity to oxidize lipids as a primary metabolic fuel source. This enhanced capacity for aerobic thermogenesis is associated with elevated activities of muscle metabolic enzymes that influence flux through fatty-acid oxidation and oxidative phosphorylation pathways in high-altitude deer mice and by concomitant changes in the expression of genes in these same pathways. Contrary to predictions derived from studies of humans at high altitude, our results suggest that selection to sustain prolonged thermogenesis under hypoxia promotes a shift in metabolic fuel use in favor of lipids over carbohydrates.
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Jeong CW, Ju J, Lee DW, Lee SH, Yoon MH. Lipid-emulsion propofol less attenuates the regulation of body temperature than micro-emulsion propofol or sevoflurane in the elderly. Yonsei Med J 2012; 53:198-203. [PMID: 22187253 PMCID: PMC3250313 DOI: 10.3349/ymj.2012.53.1.198] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
PURPOSE Anesthesia and surgery commonly cause hypothermia, and this caused by a combination of anesthetic-induced impairment of thermoregulatory control, a cold operation room environment and other factors that promote heat loss. All the general anesthetics markedly impair normal autonomic thermoregulatory control. The aim of this study is to evaluate the effect of two different types of propofol versus inhalation anesthetic on the body temperature. MATERIALS AND METHODS In this randomized controlled study, 36 patients scheduled for elective laparoscopic gastrectomy were allocated into three groups; group S (sevoflurane, n=12), group L (lipid-emulsion propofol, n=12) and group M (micro-emulsion propofol, n=12). Anesthesia was maintained with typical doses of the study drugs and all the groups received continuous remifentanil infusion. The body temperature was continuously monitored after the induction of general anesthesia until the end of surgery. RESULTS The body temperature was decreased in all the groups. The temperature gradient of each group (group S, group L and group M) at 180 minutes from induction of anesthesia was 2.5 ± 0.6°C, 1.6 ± 0.5°C and 2.3 ± 0.6°C, respectively. The body temperature of group L was significantly higher than that of group S and group M at 30 minutes and 75 minute after induction of anesthesia, respectively. There were no temperature differences between group S and group M. CONCLUSION The body temperature is maintained at a higher level in elderly patients anesthetized with lipid-emulsion propofol.
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Affiliation(s)
- Cheol Won Jeong
- Departments of Anesthesiology and Pain Medicine, Chonnam National University Medical School, Gwangju, Korea
| | - Jin Ju
- Departments of Anesthesiology and Pain Medicine, Chonnam National University Medical School, Gwangju, Korea
| | - Dae Wook Lee
- Departments of Anesthesiology and Pain Medicine, Chonnam National University Medical School, Gwangju, Korea
| | - Seong Heon Lee
- Departments of Anesthesiology and Pain Medicine, Chonnam National University Medical School, Gwangju, Korea
| | - Myung Ha Yoon
- Departments of Anesthesiology and Pain Medicine, Chonnam National University Medical School, Gwangju, Korea
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Synak M, Zarzeczny R, Górecka M, Langfort J, Kaciuba-Uściłko H, Żernicka E. Fasting increases palmitic acid incorporation into rat hind-limb intramuscular acylglycerols while short-term cold exposure has no effect. ACTA ACUST UNITED AC 2011; 98:359-66. [DOI: 10.1556/aphysiol.98.2011.3.13] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Abstract
Animals must regulate the fluxes of multiple fuels to support changing metabolic rates that result from variation in physiological circumstances. The aim of fuel selection strategies is to exploit the advantages of individual substrates while minimizing the impact of disadvantages. All exercising mammals share a general pattern of fuel selection: at the same %V(O(2,max)) they oxidize the same ratio of lipids to carbohydrates. However, highly aerobic species rely more on intramuscular fuels because energy supply from the circulation is constrained by trans-sarcolemmal transfer. Fuel selection is performed by recruiting different muscles, different fibers within the same muscles or different pathways within the same fibers. Electromyographic analyses show that shivering humans can modulate carbohydrate oxidation either through the selective recruitment of type II fibers within the same muscles or by regulating pathway recruitment within type I fibers. The selection patterns of shivering and exercise are different: at the same %V(O(2,max)), a muscle producing only heat (shivering) or significant movement (exercise) strikes a different balance between lipid and carbohydrate oxidation. Long-distance migrants provide an excellent model to characterize how to increase maximal substrate fluxes. High lipid fluxes are achieved through the coordinated upregulation of mobilization, transport and oxidation by activating enzymes, lipid-solubilizing proteins and membrane transporters. These endurance athletes support record lipolytic rates in adipocytes, use lipoprotein shuttles to accelerate transport and show increased capacity for lipid oxidation in muscle mitochondria. Some migrant birds use dietary omega-3 fatty acids as performance-enhancing agents to boost their ability to process lipids. These dietary fatty acids become incorporated in membrane phospholipids and bind to peroxisome proliferator-activated receptors to activate membrane proteins and modify gene expression.
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Affiliation(s)
- Jean-Michel Weber
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON K1N 6N5, Canada.
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Beaudry JL, McClelland GB. Thermogenesis in CD-1 mice after combined chronic hypoxia and cold acclimation. Comp Biochem Physiol B Biochem Mol Biol 2010; 157:301-9. [PMID: 20659581 DOI: 10.1016/j.cbpb.2010.07.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Revised: 07/19/2010] [Accepted: 07/20/2010] [Indexed: 01/07/2023]
Abstract
Many small mammals thermoregulate through shivering in muscle and/or non-shivering thermogenesis (NST) via brown adipose tissue (BAT) by the actions of mitochondrial uncoupling proteins (UCPs). An up-regulation of these mechanisms would be advantageous in a cold environment but not in conditions of low oxygen as it leads to needless increases in energy expenditure. We examined the chronic effect of 4 weeks of exposure to hypobaric hypoxia (H, 480 mm Hg), cold (C, 5 degrees C) and the combination of the two stressors (HC) compared to normoxic thermoneutral controls (N, 28 degrees C) in male CD-1 mice. We found that hypoxic/cold acclimated mice had significantly lower body temperatures (T(b)) after acclimation along with complete abolishment of diurnal T(b) fluctuations. Capacity for NST was assessed by changes in intrascapular BAT mass, mitochondrial content and UCP1 content per milligram mitochondria. Acclimation caused distinct remodeling of BAT that was reflected in differences in NE-induced increases in oxygen consumption (VO(2)) used to assess NST capacity. Reduction of T(b) in HC acclimated mice was not due to a decreased heat-generating capacity of BAT. VO(2) during an acute temperature challenge (32 to 4 degrees C) in normoxia was similar in all treatment groups compared to controls but thermal conductance was greater in C acclimated mice and T(b) higher in HC acclimated mice. We propose that an overriding inhibition by hypoxia on neural feedback pathways persists even after weeks of acclimation when combined with chronic cold.
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Affiliation(s)
- Jacqueline L Beaudry
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada.
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