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Notley SR, Mitchell D, Taylor NAS. A century of exercise physiology: concepts that ignited the study of human thermoregulation. Part 4: evolution, thermal adaptation and unsupported theories of thermoregulation. Eur J Appl Physiol 2024; 124:147-218. [PMID: 37796290 DOI: 10.1007/s00421-023-05262-9] [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: 02/06/2023] [Accepted: 06/13/2023] [Indexed: 10/06/2023]
Abstract
This review is the final contribution to a four-part, historical series on human exercise physiology in thermally stressful conditions. The series opened with reminders of the principles governing heat exchange and an overview of our contemporary understanding of thermoregulation (Part 1). We then reviewed the development of physiological measurements (Part 2) used to reveal the autonomic processes at work during heat and cold stresses. Next, we re-examined thermal-stress tolerance and intolerance, and critiqued the indices of thermal stress and strain (Part 3). Herein, we describe the evolutionary steps that endowed humans with a unique potential to tolerate endurance activity in the heat, and we examine how those attributes can be enhanced during thermal adaptation. The first of our ancestors to qualify as an athlete was Homo erectus, who were hairless, sweating specialists with eccrine sweat glands covering almost their entire body surface. Homo sapiens were skilful behavioural thermoregulators, which preserved their resource-wasteful, autonomic thermoeffectors (shivering and sweating) for more stressful encounters. Following emigration, they regularly experienced heat and cold stress, to which they acclimatised and developed less powerful (habituated) effector responses when those stresses were re-encountered. We critique hypotheses that linked thermoregulatory differences to ancestry. By exploring short-term heat and cold acclimation, we reveal sweat hypersecretion and powerful shivering to be protective, transitional stages en route to more complete thermal adaptation (habituation). To conclude this historical series, we examine some of the concepts and hypotheses of thermoregulation during exercise that did not withstand the tests of time.
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Affiliation(s)
- Sean R Notley
- Defence Science and Technology Group, Department of Defence, Melbourne, Australia
- School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Duncan Mitchell
- Brain Function Research Group, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa
- School of Human Sciences, University of Western Australia, Crawley, Australia
| | - Nigel A S Taylor
- Research Institute of Human Ecology, College of Human Ecology, Seoul National University, Seoul, Republic of Korea.
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2
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Wang F, Wilson TE, Deng Q. Special issue: Advancement in human and animal thermoregulation dedicated to the memory of Dr. Christopher J. Gordon. J Therm Biol 2023; 113:103525. [PMID: 37055129 DOI: 10.1016/j.jtherbio.2023.103525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 02/16/2023] [Indexed: 02/24/2023]
Affiliation(s)
- Faming Wang
- Division of Animal and Human Health Engineering, Department of Biosystems, KU Leuven, Leuven, 3001, Belgium.
| | - Thad E Wilson
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY, USA; Department of Epidemiology & Environmental Health, University of Kentucky College of Public Health, Lexington, KY, USA
| | - Qihong Deng
- School of Public Health, Zhengzhou University, Zhengzhou, China
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3
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Whole-body cryostimulation in obesity. A scoping review. J Therm Biol 2022; 106:103250. [DOI: 10.1016/j.jtherbio.2022.103250] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 03/18/2022] [Accepted: 04/30/2022] [Indexed: 12/12/2022]
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4
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Voronova IP. 5-HT Receptors and Temperature Homeostasis. Biomolecules 2021; 11:1914. [PMID: 34944557 PMCID: PMC8699715 DOI: 10.3390/biom11121914] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/11/2021] [Accepted: 12/16/2021] [Indexed: 12/28/2022] Open
Abstract
The present review summarizes the data concerning the influence of serotonin (5-HT) receptors on body temperature in warm-blooded animals and on processes associated with its maintenance. This review includes the most important part of investigations from the first studies to the latest ones. The established results on the pharmacological activation of 5-HT1A, 5-HT3, 5-HT7 and 5-HT2 receptor types are discussed. Such activation of the first 3 type of receptors causes a decrease in body temperature, whereas the 5-HT2 activation causes its increase. Physiological mechanisms leading to changes in body temperature as a result of 5-HT receptors' activation are discussed. In case of 5-HT1A receptor, they include an inhibition of shivering and non-shivering thermogenesis, as well simultaneous increase of peripheral blood flow, i.e., the processes of heat production and heat loss. The physiological processes mediated by 5-HT2 receptor are opposite to those of the 5-HT1A receptor. Mechanisms of 5-HT3 and 5-HT7 receptor participation in these processes are yet to be studied in more detail. Some facts indicating that in natural conditions, without pharmacological impact, these 5-HT receptors are important links in the system of temperature homeostasis, are also discussed.
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Affiliation(s)
- Irina P. Voronova
- Department of Thermophysiology, Scientific Research Institute of Neurosciences and Medicine, 630117 Novosibirsk, Russia
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Fang H, Kang L, Abbas Z, Hu L, Chen Y, Tan X, Wang Y, Xu Q. Identification of key Genes and Pathways Associated With Thermal Stress in Peripheral Blood Mononuclear Cells of Holstein Dairy Cattle. Front Genet 2021; 12:662080. [PMID: 34178029 PMCID: PMC8222911 DOI: 10.3389/fgene.2021.662080] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 05/10/2021] [Indexed: 12/30/2022] Open
Abstract
The objectives of the present study were to identify key genes and biological pathways associated with thermal stress in Chinese Holstein dairy cattle. Hence, we constructed a cell-model, applied various molecular biology experimental techniques and bioinformatics analysis. A total of 55 candidate genes were screened from published literature and the IPA database to examine its regulation under cold (25°C) or heat (42°C) stress in PBMCs. We identified 29 (3 up-regulated and 26 down-regulated) and 41 (15 up-regulated and 26 down-regulated) significantly differentially expressed genes (DEGs) (fold change ≥ 1.2-fold and P < 0.05) after cold and heat stress treatments, respectively. Furthermore, bioinformatics analyses confirmed that major biological processes and pathways associated with thermal stress include protein folding and refolding, protein phosphorylation, transcription factor binding, immune effector process, negative regulation of cell proliferation, autophagy, apoptosis, protein processing in endoplasmic reticulum, estrogen signaling pathway, pathways related to cancer, PI3K- Akt signaling pathway, and MAPK signaling pathway. Based on validation at the cellular and individual levels, the mRNA expression of the HIF1A gene showed upregulation during cold stress and the EIF2A, HSPA1A, HSP90AA1, and HSF1 genes showed downregulation after heat exposure. The RT-qPCR and western blot results revealed that the HIF1A after cold stress and the EIF2A, HSPA1A, HSP90AA1, and HSF1 after heat stress had consistent trend changes at the cellular transcription and translation levels, suggesting as key genes associated with thermal stress response in Holstein dairy cattle. The cellular model established in this study with PBMCs provides a suitable platform to improve our understanding of thermal stress in dairy cattle. Moreover, this study provides an opportunity to develop simultaneously both high-yielding and thermotolerant Chinese Holstein cattle through marker-assisted selection.
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Affiliation(s)
- Hao Fang
- Institute of Life Sciences and Bio-Engineering, Beijing Jiaotong University, Beijing, China
| | - Ling Kang
- Institute of Life Sciences and Bio-Engineering, Beijing Jiaotong University, Beijing, China
| | - Zaheer Abbas
- Institute of Life Sciences and Bio-Engineering, Beijing Jiaotong University, Beijing, China
| | - Lirong Hu
- Key Laboratory of Animal Genetics, Breeding and Reproduction, MARA, National Engineering Laboratory for Animal Breeding, Beijing Engineering Technology Research Center of Raw Milk Quality and Safety Control, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Yumei Chen
- Institute of Life Sciences and Bio-Engineering, Beijing Jiaotong University, Beijing, China
| | - Xiao Tan
- Institute of Life Sciences and Bio-Engineering, Beijing Jiaotong University, Beijing, China
| | - Yachun Wang
- Key Laboratory of Animal Genetics, Breeding and Reproduction, MARA, National Engineering Laboratory for Animal Breeding, Beijing Engineering Technology Research Center of Raw Milk Quality and Safety Control, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Qing Xu
- Institute of Life Sciences and Bio-Engineering, Beijing Jiaotong University, Beijing, China
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Fischl H, McManus D, Oldenkamp R, Schermelleh L, Mellor J, Jagannath A, Furger A. Cold-induced chromatin compaction and nuclear retention of clock mRNAs resets the circadian rhythm. EMBO J 2020; 39:e105604. [PMID: 33034091 PMCID: PMC7667876 DOI: 10.15252/embj.2020105604] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 08/28/2020] [Accepted: 08/29/2020] [Indexed: 12/22/2022] Open
Abstract
Cooling patients to sub‐physiological temperatures is an integral part of modern medicine. We show that cold exposure induces temperature‐specific changes to the higher‐order chromatin and gene expression profiles of human cells. These changes are particularly dramatic at 18°C, a temperature synonymous with that experienced by patients undergoing controlled deep hypothermia during surgery. Cells exposed to 18°C exhibit largely nuclear‐restricted transcriptome changes. These include the nuclear accumulation of mRNAs encoding components of the negative limbs of the core circadian clock, most notably REV‐ERBα. This response is accompanied by compaction of higher‐order chromatin and hindrance of mRNPs from engaging nuclear pores. Rewarming reverses chromatin compaction and releases the transcripts into the cytoplasm, triggering a pulse of negative limb gene proteins that reset the circadian clock. We show that cold‐induced upregulation of REV‐ERBα is sufficient to trigger this reset. Our findings uncover principles of the cellular cold response that must be considered for current and future applications involving therapeutic deep hypothermia.
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Affiliation(s)
- Harry Fischl
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - David McManus
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Roel Oldenkamp
- Department of Biochemistry, University of Oxford, Oxford, UK
| | | | - Jane Mellor
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Aarti Jagannath
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - André Furger
- Department of Biochemistry, University of Oxford, Oxford, UK
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Ripamonte GC, Bernardes-Ribeiro M, Patrone LGA, Vicente MC, Bícego KC, Gargaglioni LH. Functional role for preoptic CB1 receptors in breathing and thermal control. Neurosci Lett 2020; 732:135021. [PMID: 32454147 DOI: 10.1016/j.neulet.2020.135021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 04/12/2020] [Accepted: 04/27/2020] [Indexed: 11/30/2022]
Abstract
The anteroventral preoptic region (AVPO) of the hypothalamus is involved in both temperature and breathing regulation. This area densely express cannabinoid receptors type 1 (CB1) that modulate both excitatory and inhibitory synaptic transmission. However, it is still unknown if the endocannabinoid system located in the AVPO participates in breathing control and thermoregulation. Therefore, we tested the participation of CB1 in the AVPO in the modulation of ventilation and thermal control during normoxia and hypoxia. To this end, body temperature (Tb) of Wistar rats was monitored by datallogers and ventilation (VE) by whole body plethysmography before and after intra-AVPO microinjection of AM-251 (CB1 antagonist, 50 and 100 pmol) followed by 60 min of hypoxia exposure (7% O2). Intra-AVPO microinjection of the higher dose of AM-251 increased VE but did not change Tb under resting conditions. Exposure of rats to 7% of inspired oxygen evoked typical hypoxia-induced anapyrexia and hyperventilation after vehicle microinjection. The higher dose of the cannabinoid antagonist increased the hypoxia-induced hyperventilation, in the same magnitude as observed under normoxic condition, whereas the drop in Tb elicited by hypoxia was attenuated. Therefore, the present results demonstrate that the endocannabinoid system acting on CB1 receptors in the AVPO exerts a tonic inhibitory modulation on breathing but seem not be involved in thermoregulation during resting conditions. In addition, activation of CB1 receptors in the AVPO stimulate thermal response during hypoxia, reducing energetically expensive responses, such as the hypoxic hyperventilation.
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Affiliation(s)
- Gabriel C Ripamonte
- Department of Animal Morphology and Physiology, Sao Paulo State University, UNESP/FCAV at Jaboticabal, SP, Brazil
| | - Mariana Bernardes-Ribeiro
- Department of Animal Morphology and Physiology, Sao Paulo State University, UNESP/FCAV at Jaboticabal, SP, Brazil
| | - Luis Gustavo A Patrone
- Department of Animal Morphology and Physiology, Sao Paulo State University, UNESP/FCAV at Jaboticabal, SP, Brazil
| | - Mariane C Vicente
- Department of Animal Morphology and Physiology, Sao Paulo State University, UNESP/FCAV at Jaboticabal, SP, Brazil
| | - Kênia C Bícego
- Department of Animal Morphology and Physiology, Sao Paulo State University, UNESP/FCAV at Jaboticabal, SP, Brazil
| | - Luciane H Gargaglioni
- Department of Animal Morphology and Physiology, Sao Paulo State University, UNESP/FCAV at Jaboticabal, SP, Brazil.
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8
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Morita H, Kaji H, Ueta Y, Abe C. Understanding vestibular-related physiological functions could provide clues on adapting to a new gravitational environment. J Physiol Sci 2020; 70:17. [PMID: 32169037 PMCID: PMC7069930 DOI: 10.1186/s12576-020-00744-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 03/03/2020] [Indexed: 12/16/2022]
Abstract
The peripheral vestibular organs are sensors for linear acceleration (gravity and head tilt) and rotation. Further, they regulate various body functions, including body stability, ocular movement, autonomic nerve activity, arterial pressure, body temperature, and muscle and bone metabolism. The gravitational environment influences these functions given the highly plastic responsiveness of the vestibular system. This review demonstrates that hypergravity or microgravity induces changes in vestibular-related physiological functions, including arterial pressure, muscle and bone metabolism, feeding behavior, and body temperature. Hopefully, this review contributes to understanding how human beings can adapt to a new gravitational environment, including the moon and Mars, in future.
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Affiliation(s)
- Hironobu Morita
- Department of Physiology, Gifu University Graduate School of Medicine, Gifu, 501-1194, Japan.
| | - Hiroshi Kaji
- Department of Physiology and Regenerative Medicine, Faculty of Medicine, Kindai University, Osakasayama, 589-8511, Japan
| | - Yoichi Ueta
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, 807-8555, Japan
| | - Chikara Abe
- Department of Physiology, Gifu University Graduate School of Medicine, Gifu, 501-1194, Japan
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9
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The origin, significance and plasticity of the thermoeffector thresholds: Extrapolation between humans and laboratory rodents. J Therm Biol 2019; 85:102397. [DOI: 10.1016/j.jtherbio.2019.08.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Revised: 08/05/2019] [Accepted: 08/05/2019] [Indexed: 01/07/2023]
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10
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Silva ABC, Wrobel LC, Ribeiro FL. A thermoregulation model for whole body cooling hypothermia. J Therm Biol 2018; 78:122-130. [DOI: 10.1016/j.jtherbio.2018.08.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 08/22/2018] [Accepted: 08/24/2018] [Indexed: 11/30/2022]
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11
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Kirby AM, Fairman GD, Pamenter ME. Atypical behavioural, metabolic and thermoregulatory responses to hypoxia in the naked mole rat (Heterocephalus glaber
). J Zool (1987) 2018. [DOI: 10.1111/jzo.12542] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Alexia M Kirby
- Department of Biology; University of Ottawa; Ottawa ON Canada
| | | | - Matthew E Pamenter
- Department of Biology; University of Ottawa; Ottawa ON Canada
- Brain and Mind Research Institute; University of Ottawa; Ottawa ON Canada
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12
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Abstract
Heat exchange processes between the body and the environment are introduced. The definition of the thermoneutral zone as the ambient temperature range within which body temperature (Tb) regulation is achieved only by nonevaporative processes is explained. Thermoreceptors, thermoregulatory effectors (both physiologic and behavioral), and neural pathways and Tb signals that connect receptors and effectors into a thermoregulation system are reviewed. A classification of thermoeffectors is proposed. A consensus concept is presented, according to which the thermoregulation system is organized as a dynamic federation of independent thermoeffector loops. While the activity of each effector is driven by a unique combination of deep (core) and superficial (shell) Tbs, the regulated variable of the system can be viewed as a spatially distributed Tb with a heavily represented core and a lightly represented shell. Core Tb is the main feedback; it is always negative. Shell Tbs (mostly of the hairy skin) represent the auxiliary feedback, which can be negative or positive, and which decreases the system's response time and load error. Signals from the glabrous (nonhairy) skin about the temperature of objects in the environment serve as feedforward signals for various behaviors. Physiologic effectors do not use feedforward signals. The system interacts with other homeostatic systems by "meshing" with their loops. Coordination between different thermoeffectors is achieved through the common controlled variable, Tb. The term balance point (not set point) is used for a regulated level of Tb. The term interthreshold zone is used for a Tb range in which no effectors are activated. Thermoregulatory states are classified, based on whether: Tb is increased (hyperthermia) or decreased (hypothermia); the interthreshold zone is narrow (homeothermic type of regulation) or wide (poikilothermic type); and the balance point is increased (fever) or decreased (anapyrexia). During fever, thermoregulation can be either homeothermic or poikilothermic; anapyrexia is always a poikilothermic state. The biologic significance of poikilothermic states is discussed. As an example of practical applications of the concept presented, thermopharmacology is reviewed. Thermopharmacology uses drugs to modulate specific temperature signals at the level of a thermoreceptor (transient receptor potential channel).
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Garami A, Steiner AA, Romanovsky AA. Fever and hypothermia in systemic inflammation. HANDBOOK OF CLINICAL NEUROLOGY 2018; 157:565-597. [PMID: 30459026 DOI: 10.1016/b978-0-444-64074-1.00034-3] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Systemic inflammation-associated syndromes (e.g., sepsis and septic shock) often have high mortality and remain a challenge in emergency medicine. Systemic inflammation is usually accompanied by changes in body temperature: fever or hypothermia. In animal studies, systemic inflammation is often modeled by administering bacterial lipopolysaccharide, which triggers autonomic and behavioral thermoeffector responses and causes either fever or hypothermia, depending on the dose and ambient temperature. Fever and hypothermia are regulated changes of body temperature, which correspond to mild and severe forms of systemic inflammation, respectively. Mediators of fever and hypothermia are called endogenous pyrogens and cryogens; they are produced when the innate immune system recognizes an infectious pathogen. Upon an inflammatory challenge, hepatic and pulmonary macrophages (and later brain endothelial cells) start to release lipid mediators, of which prostaglandin (PG) E2 plays the key role, and cytokines. Blood PGE2 enters the brain and triggers fever. At later stages of fever, PGE2 synthesized within the blood-brain barrier maintains fever. In both cases, PGE2 is synthesized by cyclooxygenase-2 and microsomal PGE2synthase-1. Mediators of hypothermia are not well established. Both fever and hypothermia are beneficial host defense responses. Based on evidence from studies in laboratory animals and clinical trials in humans, fever is beneficial for fighting mild infection. Based mainly on animal studies, hypothermia is beneficial in severe systemic inflammation and infection.
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Affiliation(s)
- Andras Garami
- Institute for Translational Medicine, Medical School, University of Pécs, Pécs, Hungary.
| | - Alexandre A Steiner
- Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Andrej A Romanovsky
- Thermoregulation and Systemic Inflammation Laboratory (FeverLab), Trauma Research, St. Joseph's Hospital and Medical Center, Phoenix, AZ, United States
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Li H, Chen RK, Tang Y, Meurer W, Shih AJ. An experimental study and finite element modeling of head and neck cooling for brain hypothermia. J Therm Biol 2017; 71:99-111. [PMID: 29301706 DOI: 10.1016/j.jtherbio.2017.10.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 10/31/2017] [Accepted: 10/31/2017] [Indexed: 11/28/2022]
Abstract
Reducing brain temperature by head and neck cooling is likely to be the protective treatment for humans when subjects to sudden cardiac arrest. This study develops the experimental validation model and finite element modeling (FEM) to study the head and neck cooling separately, which can induce therapeutic hypothermia focused on the brain. Anatomically accurate geometries based on CT images of the skull and carotid artery are utilized to find the 3D geometry for FEM to analyze the temperature distributions and 3D-printing to build the physical model for experiment. The results show that FEM predicted and experimentally measured temperatures have good agreement, which can be used to predict the temporal and spatial temperature distributions of the tissue and blood during the head and neck cooling process. Effects of boundary condition, perfusion, blood flow rate, and size of cooling area are studied. For head cooling, the cooling penetration depth is greatly depending on the blood perfusion in the brain. In the normal blood flow condition, the neck internal carotid artery temperature is decreased only by about 0.13°C after 60min of hypothermia. In an ischemic (low blood flow rate) condition, such temperature can be decreased by about 1.0°C. In conclusion, decreasing the blood perfusion and metabolic reduction factor could be more beneficial to cool the core zone. The results also suggest that more SBC researches should be explored, such as the optimization of simulation and experimental models, and to perform the experiment on human subjects.
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Affiliation(s)
- Hui Li
- Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA; Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, China; Electronic Paper Display Institute, South China Normal University, Guangzhou 510006, China.
| | - Roland K Chen
- Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164-2920, USA
| | - Yong Tang
- Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, China
| | - William Meurer
- Department of Emergency Medicine, Department of Neurology, Michigan Center for Integrative Research in Critical Care, University of Michigan Health System, Ann Arbor, MI 48109-5303, USA
| | - Albert J Shih
- Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
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15
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Socała K, Nieoczym D, Kowalczuk-Vasilev E, Wyska E, Wlaź P. Increased seizure susceptibility and other toxicity symptoms following acute sulforaphane treatment in mice. Toxicol Appl Pharmacol 2017; 326:43-53. [PMID: 28412310 DOI: 10.1016/j.taap.2017.04.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/09/2017] [Accepted: 04/11/2017] [Indexed: 10/19/2022]
Abstract
Activation of Nrf2 with sulforaphane has recently gained attention as a new therapeutic approach in the treatment of many diseases, including epilepsy. As a plant-derived compound, sulforaphane is considered to be safe and well-tolerated. It is widely consumed, also by patients suffering from seizure and taking antiepileptic drugs, but no toxicity profile of sulforaphane exists. Since many natural remedies and dietary supplements may increase seizure risk and potentially interact with antiepileptic drugs, the aim of our study was to investigate the acute effects of sulforaphane on seizure thresholds and activity of some first- and second-generation antiepileptic drugs in mice. In addition, some preliminary toxicity profile of sulforaphane in mice after intraperitoneal injection was evaluated. The LD50 value of sulforaphane in mice was estimated at 212.67mg/kg, while the TD50 value - at 191.58mg/kg. In seizure tests, sulforaphane at the highest dose tested (200mg/kg) significantly decreased the thresholds for the onset of the first myoclonic twitch and generalized clonic seizure in the iv PTZ test as well as the threshold for the 6Hz-induced psychomotor seizure. At doses of 10-200mg/kg, sulforaphane did not affect the threshold for the iv PTZ-induced forelimb tonus or the threshold for maximal electroshock-induced hindlimb tonus. Interestingly, sulforaphane (at 100mg/kg) potentiated the anticonvulsant efficacy of carbamazepine in the maximal electroshock seizure test. This interaction could have been pharmacokinetic in nature, as sulforaphane increased concentrations of carbamazepine in both serum and brain tissue. The toxicity study showed that high doses of sulforaphane produced marked sedation (at 150-300mg/kg), hypothermia (at 150-300mg/kg), impairment of motor coordination (at 200-300mg/kg), decrease in skeletal muscle strength (at 250-300mg/kg), and deaths (at 200-300mg/kg). Moreover, blood analysis showed leucopenia in mice injected with sulforaphane at 200mg/kg. In conclusion, since sulforaphane was proconvulsant at a toxic dose, the safety profile and the risk-to-benefit ratio of sulforaphane usage in epileptic patients should be further evaluated.
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Affiliation(s)
- Katarzyna Socała
- Department of Animal Physiology, Institute of Biology and Biochemistry, Maria Curie-Skłodowska University, Lublin, Poland.
| | - Dorota Nieoczym
- Department of Animal Physiology, Institute of Biology and Biochemistry, Maria Curie-Skłodowska University, Lublin, Poland
| | | | - Elżbieta Wyska
- Department of Pharmacokinetics and Physical Pharmacy, Jagiellonian University Medical College, Kraków, Poland
| | - Piotr Wlaź
- Department of Animal Physiology, Institute of Biology and Biochemistry, Maria Curie-Skłodowska University, Lublin, Poland
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Central activation of the A 1 adenosine receptor in fed mice recapitulates only some of the attributes of daily torpor. J Comp Physiol B 2017; 187:835-845. [PMID: 28378088 DOI: 10.1007/s00360-017-1084-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 11/02/2016] [Accepted: 03/07/2017] [Indexed: 01/23/2023]
Abstract
Mice enter bouts of daily torpor, drastically reducing metabolic rate, core body temperature (T b), and heart rate (HR), in response to reduced caloric intake. Because central adenosine activation has been shown to induce a torpor-like state in the arctic ground squirrel, and blocking the adenosine-1 (A1) receptor prevents daily torpor, we hypothesized that central activation of the A1 adenosine receptors would induce a bout of natural torpor in mice. To test the hypothesis, mice were subjected to four different hypothermia bouts: natural torpor, forced hypothermia (FH), isoflurane-anesthesia, and an intracerebroventricular injection of the selective A1 receptor agonist N6-cyclohexyladenosine (CHA). All conditions induced profound hypothermia. T b fell more rapidly in the FH, isoflurane-anesthesia, and CHA conditions compared to torpor, while mice treated with CHA recovered at half the rate of torpid mice. FH, isoflurane-anesthesia, and CHA-treated mice exhibited a diminished drop in HR during entry into hypothermia as compared to torpor. Mice in all conditions except CHA shivered while recovering from hypothermia, and only FH mice shivered substantially while entering hypothermia. Circulating lactate during the hypothermic bouts was not significantly different between the CHA and torpor conditions, both of which had lower than baseline lactate levels. Arrhythmias were largely absent in the FH and isoflurane-anesthesia conditions, while skipped beats were observed in natural torpor and periodic extended (>1 s) HR pauses in the CHA condition. Lastly, the hypothermic bouts showed distinct patterns of gene expression, with torpor characterized by elevated hepatic and cardiac Txnip expression and all other hypothermic states characterized by elevated c-Fos and Egr-1 expression. We conclude that CHA-induced hypothermia and natural torpor are largely different physiological states.
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Morrison SA, Ciuha U, Zavec-Pavlinić D, Eiken O, Mekjavic IB. The effect of a Live-high Train-high exercise regimen on behavioural temperature regulation. Eur J Appl Physiol 2016; 117:255-265. [PMID: 28025662 DOI: 10.1007/s00421-016-3515-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 12/08/2016] [Indexed: 11/28/2022]
Abstract
PURPOSE Acute hypoxia alters the threshold for sensation of cutaneous thermal stimuli. We hypothesised that hypoxia-induced alterations in cutaneous temperature sensation may lead to modulation of the perception of temperature, ultimately influencing behavioural thermoregulation and that the magnitude of this effect could be influenced by daily physical training. METHODS Fourteen men were confined 10 days to a normobaric hypoxic environment (PIO2 = 88.2 ± 0.6 mmHg, corresponding to 4175 m elevation). Subjects were randomly assigned to a non-exercising (Live-high, LH, N = 6), or exercising group (Live-high Train-high, LH-TH, N = 8) comprised of 1-h bouts of cycle ergometry, twice daily, at a work-rate equivalent to 50% hypoxic peak power output. A subset of subjects (N = 5) also completed a control trial under normoxic conditions. The thermal comfort zone (TCZ) was determined in normoxia, and during hypoxic confinement days 2 (HC2) and 10 (HC10) in both groups using a water-perfused suit in which water temperature was regulated by the subjects within a range, they deemed thermally comfortable. Mean skin temperature and proximal-distal temperature gradients (two sites: forearm-fingertip, calf-toe) were recorded each minute throughout the 60-min protocol. RESULTS The average width of the TCZ did not differ between the control group (9.0 ± 6.9 °C), and the LH and LH-TH groups on days HC2 (7.2 ± 4.2 °C) and HC10 (10.2 ± 7.5 °C) of the hypoxic exposure (p = 0.256). [Formula: see text] was marginally higher on HC2 (35.9 ± 1.0 °C) compared to control (34.9 ± 0.8 °C, p = 0.040), but not on HC10 (35.6 ± 1.0 °C), reflecting the responses of hand perfusion. CONCLUSION There was a little systematic effect of hypoxia or exercise training on TCZ magnitude or boundary temperatures.
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Affiliation(s)
- Shawnda A Morrison
- Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia. .,Faculty of Mathematics, Natural Sciences and Information Technology, University of Primorska, Titov trg 4, 6000, Koper, Slovenia.
| | - Urša Ciuha
- Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia
| | - Daniela Zavec-Pavlinić
- Faculty of Mechanical Engineering, University of Maribor, Smetanova ulica 17, 2000, Maribor, Slovenia
| | - Ola Eiken
- Department of Environmental Physiology, Swedish Aerospace Physiology Centre, Royal Institute of Technology, Berzelius v. 13, Stockholm, Sweden
| | - Igor B Mekjavic
- Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia.,Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
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Schieber AMP, Ayres JS. Thermoregulation as a disease tolerance defense strategy. Pathog Dis 2016; 74:ftw106. [PMID: 27815313 PMCID: PMC5975229 DOI: 10.1093/femspd/ftw106] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 04/03/2016] [Accepted: 11/02/2016] [Indexed: 12/28/2022] Open
Abstract
Physiological responses that occur during infection are most often thought of in terms of effectors of microbial destruction through the execution of resistance mechanisms, due to a direct action of the microbe, or are maladaptive consequences of host-pathogen interplay. However, an examination of the cellular and organ-level consequences of one such response, thermoregulation that leads to fever or hypothermia, reveals that these actions cannot be readily explained within the traditional paradigms of microbial killing or maladaptive consequences of host-pathogen interactions. In this review, the concept of disease tolerance is applied to thermoregulation during infection, inflammation and trauma, and we discuss the physiological consequences of thermoregulation during disease including tissue susceptibility to damage, inflammation, behavior and toxin neutralization.
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Affiliation(s)
- Alexandria M Palaferri Schieber
- The Salk Institute for Biological Studies, Immunobiology and Microbial Pathogenesis, 10010 North Torrey Pines Road, San DIego CA, USA
| | - Janelle S Ayres
- The Salk Institute for Biological Studies, Immunobiology and Microbial Pathogenesis, 10010 North Torrey Pines Road, San DIego CA, USA
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Silva ABC, Laszczyk J, Wrobel LC, Ribeiro FL, Nowak AJ. A thermoregulation model for hypothermic treatment of neonates. Med Eng Phys 2016; 38:988-98. [DOI: 10.1016/j.medengphy.2016.06.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 04/01/2016] [Accepted: 06/09/2016] [Indexed: 11/26/2022]
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Fonseca MT, Rodrigues AC, Cezar LC, Fujita A, Soriano FG, Steiner AA. Spontaneous hypothermia in human sepsis is a transient, self-limiting, and nonterminal response. J Appl Physiol (1985) 2016; 120:1394-401. [PMID: 26989218 DOI: 10.1152/japplphysiol.00004.2016] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Accepted: 03/15/2016] [Indexed: 11/22/2022] Open
Abstract
Hypothermia in sepsis is generally perceived as something dysregulated and progressive although there has been no assessment on the natural course of this phenomenon in humans. This was the first study on the dynamics of hypothermia in septic patients not subjected to active rewarming, and the results were surprising. A sample of 50 subjects presenting with spontaneous hypothermia during sepsis was drawn from the 2005-2012 database of an academic hospital. Hypothermia was defined as body temperature below 36.0°C for longer than 2 h, with at least one reading of 35.5°C or less. The patients presented with 138 episodes of hypothermia, 21 at the time of the sepsis diagnosis and 117 with a later onset. However, hypothermia was uncommon in the final 12 h of life of the patients that succumbed. The majority (97.1%) of the hypothermic episodes were transient and self-limited; the median recovery time was 6 h; body temperature rarely fell below 34.0°C. Bidirectional oscillations in body temperature were evident in the course of hypothermia. Nearly half of the hypothermic episodes had onset in the absence of shock or respiratory distress, and the incidence of hypothermia was not increased during either of these conditions. Usage of antipyretic drugs, sedatives, neuroleptics, or other medications did not predict the onset of hypothermia. In conclusion, hypothermia appears to be a predominantly transient, self-limiting, and nonterminal phenomenon that is inherent to human sepsis. These characteristics resemble those of the regulated hypothermia shown to replace fever in animal models of severe systemic inflammation.
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Affiliation(s)
- Monique T Fonseca
- Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Abner C Rodrigues
- Institute of Mathematics and Statistics, University of São Paulo, São Paulo, Brazil
| | - Luana C Cezar
- Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Andre Fujita
- Institute of Mathematics and Statistics, University of São Paulo, São Paulo, Brazil
| | | | - Alexandre A Steiner
- Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil;
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21
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Accompanying mild hypothermia significantly improved the prognosis of septic mice than artificial mild hypothermia. Am J Emerg Med 2015; 33:1651-8. [DOI: 10.1016/j.ajem.2015.08.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 07/29/2015] [Accepted: 08/02/2015] [Indexed: 02/05/2023] Open
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Dirkes MC, van Gulik TM, Heger M. Survey and critical appraisal of pharmacological agents with potential thermo-modulatory properties in the context of artificially induced hypometabolism. J Clin Transl Res 2015; 1:6-21. [PMID: 30873441 PMCID: PMC6410648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Revised: 07/07/2015] [Accepted: 07/10/2015] [Indexed: 10/27/2022] Open
Abstract
A reduction in body temperature can be achieved by a downward adjustment of the termoneutral zone, a process also described as anapyrexia. Pharmacological induction of anapyrexia could enable numerous applications in medicine. However, little is known about the potential of pharmacological agents to induce anapyrexic signaling. Therefore, a review of literature was performed and over a thousand pharmacologically active compounds were analyzed for their ability to induce anapyrexia in animals. Based on this analysis, eight agents (helium, dimethyl sulfoxide, reserpine, (oxo)tremorine, pentobarbital, (chlor) promazine, insulin, and acetaminophen) were identified as potential anapyrexia-inducing compounds and discussed in detail. The translational pitfalls were also addressed for each candidate compound. Of the agents that were discussed, reserpine, (oxo)tremorine, and (chlor) promazine may possess true anapyrexic properties based on their ability to either affect the thermoneutral zone or its effectors and facilitate hypothermic signaling. However, these properties are currently not unequivocal and warrant further examination in the context of artificially-induced hypometabolism.
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Affiliation(s)
- Marcel C. Dirkes
- Department of Experimental Surgery, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands, Current affiliation: Philips Research, Eindhoven, the Netherlands
| | - Thomas M. van Gulik
- Department of Experimental Surgery, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Michal Heger
- Department of Experimental Surgery, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
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Effect of a pharmacologically induced decrease in core temperature in rats resuscitated from cardiac arrest. Resuscitation 2015; 92:26-31. [PMID: 25906943 DOI: 10.1016/j.resuscitation.2015.04.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 04/01/2015] [Accepted: 04/11/2015] [Indexed: 01/09/2023]
Abstract
AIM Hypothermia is recommended by international guidelines for treatment of unconscious survivors of cardiac arrest to improve neurologic outcomes. However, temperature management is often underutilized because it may be difficult to implement. The present study evaluated the efficacy of pharmacologically induced hypothermia on survival and neurological outcome in rats resuscitated from cardiac arrest. METHODS Cardiac arrest was induced for 10 min in 120 rats. Sixty-one rats were resuscitated and randomized to normothermia, physical cooling or pharmacological hypothermia 5 min after resuscitation. Pharmacological hypothermia rats received a combination of ethanol, vasopressin and lidocaine (HBN-1). Physical hypothermia rats were cooled with intravenous iced saline and cooling pads. Rats in the pharmacological hypothermia group received HBN-1 at ambient temperature (20 °C). Normothermic rats were maintained at 37.3 ± 0.2 °C. RESULTS HBN-1 (p < 0.0001) shortened the time (85 ± 71 min) to target temperature (33.5 °C) versus physical hypothermia (247 ± 142 min). The duration of hypothermia was 17.0 ± 6.8h in the HBN-1 group and 17.3 ± 7.5h in the physical hypothermia group (p = 0.918). Survival (p = 0.034), neurological deficit scores (p < 0.0001) and Morris Water Maze performance after resuscitation (p = 0.041) was improved in the HBN-1 versus the normothermic group. HBN-1 improved survival and early neurological outcome compared to the physical hypothermia group while there was no significant difference in performance in the Morris water maze. CONCLUSION HBN-1 induced rapid and prolonged hypothermia improved survival with good neurological outcomes after cardiac arrest suggesting that pharmacologically induced regulated hypothermia may provide a practical alternative to physical cooling.
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Branco LG, Soriano RN, Steiner AA. Gaseous Mediators in Temperature Regulation. Compr Physiol 2014; 4:1301-38. [DOI: 10.1002/cphy.c130053] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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25
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Katz LM, McGwin G, Gordon CJ. Drug-induced therapeutic hypothermia after asphyxial cardiac arrest in swine. Ther Hypothermia Temp Manag 2014; 2:176-82. [PMID: 24716490 DOI: 10.1089/ther.2012.0017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A feasibility study was performed to compare an investigational drug, HBN-1, to forced cooling to induce hypothermia after resuscitation in a translation model of asphyxial cardiac arrest in swine. Serum and cerebral spinal fluid neuron-specific enolase activity (sNSE and csfNSE) were measured after cardiac arrest as surrogate markers of brain injury. In a block design, swine resuscitated from 10 minutes of asphyxial cardiac arrest were infused intravenously with HBN-1 or iced saline vehicle (forced hypothermia [FH]) 5 to 45 minutes after return of spontaneous circulation (ROSC). External cooling in both groups was added 45 minutes after ROSC until hypothermia (T=4°C below baseline) was attained. Esophageal (core) temperature, shivering, cardiopulmonary parameters, and time to hypothermia after ROSC were monitored. sNSE and csfNSE were measured 180 minutes after ROSC. HBN-1 induced hypothermia significantly lowered temperature compared to FH 5-45 minutes after ROSC (p<0.0001). Time to hypothermia was reduced by HBN-1 (93±6 minutes) compared to FH (177±10 minutes) (p<0.0001). HBN-1 sNSE (0.7±1.9 ng/mL) and csfNSE (17.3±1.9 ng/mL) were lower compared to FH (6±1.6 ng/mL) and (49.7±32.0 ng/mL) (p<0.0001, p=0.022, respectively). There was no shivering with HBN-1 cooling while all FH cooled swine shivered (p<0.0001). The time to reach target hypothermia after cardiac arrest was reduced by nearly 50% with HBN-1 compared to the FH method of inducing hypothermia. Moreover, surrogate biomarkers of brain injury were significantly reduced with HBN-1 as compared to FH. While HBN-1-induced hypothermia shows promise for being neuroprotective, survival studies are needed to confirm these preliminary findings.
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Affiliation(s)
- Laurence M Katz
- 1 Department Emergency Medicine, University of North Carolina School of Medicine , Chapel Hill, North Carolina
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26
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Abstract
Homeostasis, the dominant explanatory framework for physiological regulation, has undergone significant revision in recent years, with contemporary models differing significantly from the original formulation. Allostasis, an alternative view of physiological regulation, goes beyond its homeostatic roots, offering novel insights relevant to our understanding and treatment of several chronic health conditions. Despite growing enthusiasm for allostasis, the concept remains diffuse, due in part to ambiguity as to how the term is understood and used, impeding meaningful translational and clinical research on allostasis. Here, we provide a more focused understanding of homeostasis and allostasis by explaining how both play a role in physiological regulation, and a critical analysis of regulation suggests how homeostasis and allostasis can be distinguished. Rather than focusing on changes in the value of a regulated variable (e.g., body temperature, body adiposity, or reward), research investigating the activity and relationship among the multiple regulatory loops that influence the value of these regulated variables may be the key to distinguishing homeostasis and allostasis. The mechanisms underlying physiological regulation and dysregulation are likely to have important implications for health and disease.
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Affiliation(s)
- Douglas S. Ramsay
- Department of Oral Health Sciences, University of Washington, Seattle, Washington, USA
- Department of Orthodontics, University of Washington, Seattle, Washington, USA
- Department of Pediatric Dentistry, University of Washington, Seattle, Washington, USA
| | - Stephen C. Woods
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati Medical Center, Cincinnati, Ohio, USA
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27
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Kwiatkoski M, Soriano RN, da Silva GSF, Francescato HD, Coimbra TM, Glass ML, Carnio EC, Branco LGS. Endogenous preoptic hydrogen sulphide attenuates hypoxia-induced hyperventilation. Acta Physiol (Oxf) 2014; 210:913-27. [PMID: 24119224 DOI: 10.1111/apha.12177] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2013] [Revised: 07/06/2013] [Accepted: 09/26/2013] [Indexed: 11/27/2022]
Abstract
AIM We hypothesized that hydrogen sulphide (H2 S), acting specifically in the anteroventral preoptic region (AVPO - an important integrating site of thermal and cardiorespiratory responses to hypoxia in which H2 S synthesis has been shown to be increased under hypoxic conditions), modulates the hypoxic ventilatory response. METHODS To test this hypothesis, we measured pulmonary ventilation (V˙E) and deep body temperature of rats before and after intracerebroventricular (icv) or intra-AVPO microinjection of aminooxyacetate (AOA; CBS inhibitor) or Na2 S (H2 S donor) followed by 60 min of hypoxia exposure (7% O2 ). Furthermore, we assessed the AVPO levels of H2 S of rats exposed to hypoxia. Control rats were kept under normoxia. RESULTS Microinjection of vehicle, AOA or Na2 S did not change V˙E under normoxic conditions. Hypoxia caused an increase in ventilation, which was potentiated by microinjection of AOA because of a further augmented tidal volume. Conversely, treatment with Na2 S significantly attenuated this response. The in vivo H2 S data indicated that during hypoxia the lower the deep body temperature the smaller the degree of hyperventilation. Under hypoxia, H2 S production was found to be increased in the AVPO, indicating that its production is responsive to hypoxia. The CBS inhibitor attenuated the hypoxia-induced increase in the H2 S synthesis, suggesting an endogenous synthesis of the gas. CONCLUSION These data provide solid evidence that AVPO H2 S production is stimulated by hypoxia, and this gaseous messenger exerts an inhibitory modulation of the hypoxic ventilatory response. It is probable that the H2 S modulation of hypoxia-induced hyperventilation is at least in part in proportion to metabolism.
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Affiliation(s)
- M. Kwiatkoski
- Medical School of Ribeirão Preto; University of São Paulo; Ribeirão Preto SP Brazil
| | - R. N. Soriano
- Nursing School of Ribeirão Preto; University of São Paulo; Ribeirão Preto SP Brazil
- Dental School of Ribeirão Preto; University of São Paulo; Ribeirão Preto SP Brazil
| | - G. S. F. da Silva
- Dental School of Ribeirão Preto; University of São Paulo; Ribeirão Preto SP Brazil
| | - H. D. Francescato
- Medical School of Ribeirão Preto; University of São Paulo; Ribeirão Preto SP Brazil
| | - T. M. Coimbra
- Medical School of Ribeirão Preto; University of São Paulo; Ribeirão Preto SP Brazil
| | - M. L. Glass
- Medical School of Ribeirão Preto; University of São Paulo; Ribeirão Preto SP Brazil
| | - E. C. Carnio
- Nursing School of Ribeirão Preto; University of São Paulo; Ribeirão Preto SP Brazil
| | - L. G. S. Branco
- Dental School of Ribeirão Preto; University of São Paulo; Ribeirão Preto SP Brazil
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Khan SA, Chiu GS, Dubin JA. Therapeutic Hypothermia: Quantification of the Transition of Core Body Temperature Using the Flexible Mixture Bent-Cable Model for Longitudinal Data. AUST NZ J STAT 2014. [DOI: 10.1111/anzs.12047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Shahedul A. Khan
- Department of Mathematics and Statistics; University of Saskatchewan; Saskatoon SK S7N 5E6 Canada
| | - Grace S. Chiu
- CSIRO Computational Informatics; GPO Box 664 Canberra ACT 2601 Australia
- Department of Statistics and Actuarial Science; University of Waterloo; Waterloo ON N2L 3G1 Canada
| | - Joel A. Dubin
- Department of Statistics and Actuarial Science; University of Waterloo; Waterloo ON N2L 3G1 Canada
- School of Public Health and Health Systems; University of Waterloo; Waterloo ON N2L 3G1 Canada
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Bowers J, Terrien J, Clerget-Froidevaux MS, Gothié JD, Rozing MP, Westendorp RGJ, van Heemst D, Demeneix BA. Thyroid hormone signaling and homeostasis during aging. Endocr Rev 2013; 34:556-89. [PMID: 23696256 DOI: 10.1210/er.2012-1056] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Studies in humans and in animal models show negative correlations between thyroid hormone (TH) levels and longevity. TH signaling is implicated in maintaining and integrating metabolic homeostasis at multiple levels, notably centrally in the hypothalamus but also in peripheral tissues. The question is thus raised of how TH signaling is modulated during aging in different tissues. Classically, TH actions on mitochondria and heat production are obvious candidates to link negative effects of TH to aging. Mitochondrial effects of excess TH include reactive oxygen species and DNA damage, 2 factors often considered as aging accelerators. Inversely, caloric restriction, which can retard aging from nematodes to primates, causes a rapid reduction of circulating TH, reducing metabolism in birds and mammals. However, many other factors could link TH to aging, and it is these potentially subtler and less explored areas that are highlighted here. For example, effects of TH on membrane composition, inflammatory responses, stem cell renewal and synchronization of physiological responses to light could each contribute to TH regulation of maintenance of homeostasis during aging. We propose the hypothesis that constraints on TH signaling at certain life stages, notably during maturity, are advantageous for optimal aging.
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Affiliation(s)
- J Bowers
- Muséum national d'Histoire Naturelle, Laboratoire de Physiologie Générale et Comparée, Unité Mixte de Recherche, Centre National de la Recherche Scientifique 7221, 75231 Paris cedex 5, France
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Jain K, Suryakumar G, Prasad R, Singh SN, Ganju L. Myocardial ER chaperone activation and protein degradation occurs due to synergistic, not individual, cold and hypoxic stress. Biochimie 2013; 95:1897-908. [PMID: 23816873 DOI: 10.1016/j.biochi.2013.06.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 06/19/2013] [Indexed: 11/25/2022]
Abstract
Environmental stress at high altitude affects the myocardium at the physiological and molecular level. Characterized by hypobaric hypoxia and low temperatures, the cumulative impact of these stressors on the protein folding homeostasis in the heart is yet unexplored. The present study evaluates the collective effect of cold and hypoxia on the myocardial protein oxidation and activation of the endoplasmic reticulum (ER) stress response. Adult rats were exposed to either a singular acute stress of cold (10 °C; C), hypobaric hypoxia (7620 m; H) or simultaneously to both cold and hypobaric hypoxia (CH) for 6 h. Hypoxic stress amplified the free radical generation in H and CH groups, leading to enhanced HIF-1α expression. Coupled to cold stress, reduced oxygen availability caused substantial protein oxidative modifications, as well as cardiac tissue injury and matrix remodeling, evident in the histological staining. Presence of oxidized proteins caused a significant upregulation in expression of ER chaperones GRP78 and PDI in the cold hypoxia exposed animals. Enhanced proteolytic activity signaled the removal of misfolded proteins. Linked intricately to cellular stress response, cell survival kinases were expressed higher in CH group; however apoptotic CHOP (C/EBP homologous protein) expression remained unaltered. Administration of ER stress inducer, tunicamycin along with cold hypoxic stress, caused a discernible increase in protein oxidation and GRP78 expression, along with a significant elevation in proteasome and apoptotic activity. Highlighting the significance of a synergistic, rather than individual, effect of low oxygen and temperature on the protein folding machinery, our study provides evidence for the activation of ER stress response in the myocardium under acute high altitude stress.
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Affiliation(s)
- Kanika Jain
- Cellular Biochemistry Group, Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi 110054, India
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Abstract
The hypometabolic state of torpor is a widely utilized and well-orchestrated response to food shortage. A new study shows that the melatonin-related orphan receptor GPR50 plays an important function in metabolic regulation for entry into torpor.
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Affiliation(s)
- Steven J Swoap
- Department of Biology, Williams College, Williamstown, MA 01267, USA.
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Miller E, Markiewicz Ł, Saluk J, Majsterek I. Effect of short-term cryostimulation on antioxidative status and its clinical applications in humans. Eur J Appl Physiol 2012; 112:1645-52. [PMID: 21874554 PMCID: PMC3324698 DOI: 10.1007/s00421-011-2122-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Accepted: 08/08/2011] [Indexed: 11/10/2022]
Abstract
Whole body cryostimulation (WBCT) is becoming popular in medicine and sport as an adjuvant form of treatment since late 1970s. Only a few works concerning antioxidant protection after WBCT have been published. The aim of this study was to determine the effect of a ten 3-min-long exposures (one exposure per day) to cryogenic temperature (-130 °C) on the level of total antioxidant status (TAS), activity of selected antioxidant enzyme superoxide dismutase (SOD) and main non-enzymatic antioxidant-uric acid (UA) in WBCT study group (man n = 24; female n = 22) and non-WBCT control subjects (man n = 22; female n = 26). Moreover, we evaluated the lipid peroxidation measured as thiobarbituric acid reactive substances products. Their blood samples were collected twice at an interval of 10 days in both study group and control subjects. The activity of antioxidant enzyme and lipid peroxidation was assayed in erythrocytes, while the concentration of uric acid was measured in plasma. After completing a total of ten WBCT sessions a significant increase (p < 0.001) of TAS and UA levels in plasma (p < 0.001) in comparison to non-WBCT was observed. Our data showed that there was statistically significant increase of the activities of SOD in erythrocytes obtained from WBCT study group compared to non-WBCT controls after 10 days of treatment (p < 0.001). It was concluded that expositions to extremely low temperatures use in cryostimulation improve the antioxidant capacity of organism.
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Affiliation(s)
- Elżbieta Miller
- Rehabilitation Ward, III General Hospital in Lodz, Milionowa 14, Lodz, Poland
- Łyżwiarska 31, 94-124 Lodz, Poland
| | - Łukasz Markiewicz
- Department of Chemistry and Clinical Biochemistry, Medical University of Lodz, Pl. Hallera 1, Lodz, Poland
| | - Joanna Saluk
- Department of General Biochemistry, University of Lodz, Banacha 12/16, Lodz, Poland
| | - Ireneusz Majsterek
- Department of Chemistry and Clinical Biochemistry, Medical University of Lodz, Pl. Hallera 1, Lodz, Poland
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Sant’Anna G, Laptook AR, Shankaran S, Bara R, McDonald SA, Higgins RD, Tyson JE, Ehrenkranz RA, Das A, Goldberg RN, Walsh MC. Phenobarbital and temperature profile during hypothermia for hypoxic-ischemic encephalopathy. J Child Neurol 2012; 27:451-7. [PMID: 21960671 PMCID: PMC3530920 DOI: 10.1177/0883073811419317] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Data from the whole-body hypothermia trial was analyzed to examine the effects of phenobarbital administration prior to cooling (+PB) on the esophageal temperature (T (e)) profile, during the induction phase of hypothermia. A total of 98 infants were analyzed. At enrollment, +PB infants had a higher rate of severe hypoxic-ischemic encephalopathy and clinical seizures and lower T (e) and cord pH than infants that have not received phenobarbital (-PB). There was a significant effect of phenobarbital itself and an interaction between phenobarbital and time in the T (e) profile. Mean T (e) in the +PB group was lower than in the -PB group, and the differences decreased over time. In +PB infants, the time to surpass target T (e) of 33.5°C and to reach the minimum T (e) during overshoot were shorter. In conclusion, the administration of phenobarbital before cooling was associated with changes that may reflect a reduced thermogenic response associated with barbiturates.
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Affiliation(s)
| | | | | | | | | | - Rosemary D. Higgins
- Eunice Kennedy Shriver National Institute of Child Health and Human Development
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Dae MW. Hypothermia and percutaneous coronary intervention during acute myocardial infarction. Interv Cardiol 2012. [DOI: 10.2217/ica.12.14] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Rezvani AH, Timofeeva O, Sexton HG, DeCuir D, Xiao Y, Gordon CJ, Kellar KJ, Levin ED. Effects of sazetidine-A, a selective α4β2* nicotinic receptor desensitizing agent, on body temperature regulation in mice and rats. Eur J Pharmacol 2012; 682:110-7. [PMID: 22387853 DOI: 10.1016/j.ejphar.2012.02.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 02/07/2012] [Accepted: 02/15/2012] [Indexed: 01/06/2023]
Abstract
Nicotine-induced hypothermia is well established, but the nicotinic receptor actions underlying this effect are not clear. Nicotine causes activation and desensitization at a variety of nicotinic receptor subtypes. Sazetidine-A [6-(5(((S)-azetidine-2-yl)methoxy)pyridine-3-yl)hex-5-yn-1-ol] is a novel compound that potently and selectively desensitizes α4β2* nicotinic receptors. The main goal of this study was to investigate the effects of sazetidine-A, on core body temperature (Tc) in mice and rats. Sazetidine-A effects on Tc and the interactions of sazetidine-A with nicotine and selective nicotinic antagonists were investigated to determine the receptor actions underlying nicotine-induced hypothermia. Adult male mice were injected with different dose of nicotine (0.2, 0.4 and 0.8 mg/kg), sazetidine-A (0.3, 1, and 3mg/kg), a mixture of nicotine (0.4 or 0.8 mg/kg) and sazetidine-A (0.3 or 0.6 mg/kg) or saline and Tc was monitored telemetrically. In another set of experiments, the interaction between sazetidine-A and dihydro-β-erythroidine (DHβE), an α4β2* nicotinic receptors antagonist, and methyllycaconitine (MLA), an α7 antagonist, was investigated. Tc of mice was monitored following DHβE (1, 3 and 6 mg/kg), a combination of DHβE (3mg/kg) and sazetidine-A (0.6 mg/kg), MLA (1.5, 3 or 6 mg/kg) or combination of MLA (6 mg/kg) and sazetidine (0.6 mg/kg) or saline. The acute effect of sazetidine-A (1, 3, and 6 mg/kg) on rats Tc was also studied. Acute sazetidine-A caused a pronounced and long-lasting hypothermia in mice; Tc decreased to about 28°C at 100 min and recovered within 230 min. The hypothermic effect of sazetidine in rats was much less in magnitude (about 3°C) and shorter in duration compared with that in mice. Nicotine co-administration with low doses of sazetidine potentiated the magnitude and duration of hypothermia in mice. The α4β2* nicotinic receptors antagonist DHβE significantly prolonged sazetidine-A-induced hypothermia but did not increase its depth. The α7 antagonist MLA caused a modest degree of hypothermia with relatively short duration in mice. MLA failed to counteract the sazetidine-A-induced hypothermia. Overall, our results show that pharmacological modulation of α4β2* nicotinic receptors elicits changes in body temperature that may involve desensitization of these receptors.
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Affiliation(s)
- Amir H Rezvani
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA.
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Mitra P, Brownstone RM. An in vitro spinal cord slice preparation for recording from lumbar motoneurons of the adult mouse. J Neurophysiol 2011; 107:728-41. [PMID: 22031766 DOI: 10.1152/jn.00558.2011] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The development of central nervous system slice preparations for electrophysiological studies has led to an explosion of knowledge of neuronal properties in health and disease. Studies of spinal motoneurons in these preparations, however, have been largely limited to the early postnatal period, as adult motoneurons are vulnerable to the insults sustained by the preparation. We therefore sought to develop an adult spinal cord slice preparation that permits recording from lumbar motoneurons. To accomplish this, we empirically optimized the composition of solutions used during preparation in order to limit energy failure, reduce harmful ionic fluxes, mitigate oxidative stress, and prevent excitotoxic cell death. In addition to other additives, this involved the use of ethyl pyruvate, which serves as an effective nutrient and antioxidant. We also optimized and incorporated a host of previously published modifications used for other in vitro preparations, such as the use of polyethylene glycol. We provide an in-depth description of the preparation protocol and discuss the rationale underlying each modification. By using this protocol, we obtained stable whole cell patch-clamp recordings from identified fluorescent protein-labeled motoneurons in adult slices; here, we describe the firing properties of these adult motoneurons. We propose that this preparation will allow further studies of how motoneurons integrate activity to produce adult motor behaviors and how pathological processes such as amyotrophic lateral sclerosis affect these neurons.
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Affiliation(s)
- Pratip Mitra
- Department of Anatomy and Neurobiology, Dalhousie University, Halifax, Nova Scotia, Canada
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Miller E, Mrowicka M, Malinowska K, Mrowicki J, Saluk-Juszczak J, Kędziora J. Effects of whole-body cryotherapy on a total antioxidative status and activities of antioxidative enzymes in blood of depressive multiple sclerosis patients. World J Biol Psychiatry 2011; 12:223-7. [PMID: 21083503 DOI: 10.3109/15622975.2010.518626] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVES Oxidative stress (OS) plays an important role in the pathogenesis of multiple sclerosis (MS). In MS patients depression is often observed. Cryotherapy might have an effect on OS. The aim of this study was to compare the effects of whole body cryotherapy (WBCT) on changes in total antioxidative status (TAS) of plasma and activities of antioxidative enzymes in erythrocytes from depressive and non depressive MS patients. METHODS Twenty-two MS patients with secondary progressive disease course (12 depressive and 10 non depressive) were treated with 10 exposures in a cryochamber. Before and after WBCT the plasma TAS and the activities of superoxide dismutase (SOD) and catalase (CAT) in the erythrocytes were measured. RESULTS The level of TAS in depressive MS group was significantly lower than in non depressive MS (P < 0.0003). WBCT increased the level of TAS in depressive (P < 0.002) more than in non depressive MS patients (P < 0.01). WBCT treatment of MS patients resulted in the significant increase of TAS level in plasma but had no effects on activities of SOD and CAT. CONCLUSIONS Our results indicate that WBCT suppresses OS in MS patients, especially in depressive patients.
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Affiliation(s)
- Elżbieta Miller
- Neurorehabilitation Ward, III General Hospital Lodz, Lodz, Poland.
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Bertolizio G, Mason L, Bissonnette B. Brain temperature: heat production, elimination and clinical relevance. Paediatr Anaesth 2011; 21:347-58. [PMID: 21371165 DOI: 10.1111/j.1460-9592.2011.03542.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Neurological insults are a leading cause of morbidity and mortality, both in adults and especially in children. Among possible therapeutic strategies to limit clinical cerebral damage and improve outcomes, hypothermia remains a promising and beneficial approach. However, its advantages are still debated after decades of use. Studies in adults have generated conflicting results, whereas in children recent data even suggest that hypothermia may be detrimental. Is it because brain temperature physiology is not well understood and/or not applied properly, that hypothermia fails to convince clinicians of its potential benefits? Or is it because hypothermia is not, as believed, the optimal strategy to improve outcome in patients affected with an acute neurological insult? This review article should help to explain the fundamental physiological principles of brain heat production, distribution and elimination under normal conditions and discuss why hypothermia cannot yet be recommended routinely in the management of children affected with various neurological insults.
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Ramsay DS, Seaman J, Kaiyala KJ. Nitrous oxide causes a regulated hypothermia: rats select a cooler ambient temperature while becoming hypothermic. Physiol Behav 2010; 103:79-85. [PMID: 21184766 DOI: 10.1016/j.physbeh.2010.12.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2010] [Revised: 11/24/2010] [Accepted: 12/15/2010] [Indexed: 11/26/2022]
Abstract
An initial administration of 60% nitrous oxide (N(2)O) evokes hypothermia in rats and if the administration continues for more than 1-2h, acute tolerance typically develops such that the initial reduction in core temperature (Tc) reverses and Tc recovers toward control values. Calorimeter studies at normal ambient temperature indicate that hypothermia results from a transient reduction in heat production (HP) combined with an elevation in heat loss. Acute tolerance develops primarily due to progressive increases in HP. Our aim was to determine whether rats provided a choice of ambient temperatures would behaviorally facilitate or oppose N(2)O-induced hypothermia. A gas-tight thermally-graded alleyway (range, 6.7-37.0°C) enabled male Long-Evans rats (n=12) to select a preferred ambient temperature during a 5-hour steady-state administration of 60% N(2)O and a separate paired control gas exposure (order counterbalanced). Tc was measured telemetrically from a sensor surgically implanted into the peritoneal cavity >7days before testing. Internal LED lighting maintained the accustomed day:night cycle (light cycle 0700-1900h) during sessions lasting 45.5h. Rats entered the temperature gradient at 1100h, and the 5-h N(2)O or control gas period did not start until 23h later to provide a long habituation/training period. Food and water were provided ad libitum at the center of the alleyway. The maximum decrease of mean Tc during N(2)O administration occurred at 0.9h and was -2.05±0.25°C; this differed significantly (p<0.0001) from the corresponding Tc change at 0.9h during control gas administration (0.01±0.14°C). The maximum decrease of the mean selected ambient temperature during N(2)O administration occurred at 0.7h and was -13.58±1.61°C; this differed significantly (p<0.0001) from the corresponding mean change in the selected ambient temperature at 0.7h during control gas administration (0.30±1.49°C). N(2)O appears to induce a regulated hypothermia because the selection of a cool ambient temperature facilitates the reduction in Tc. The recovery of Tc during N(2)O administration (i.e., acute tolerance development) could have been facilitated by selection of ambient temperatures that were warmer than those chosen during control administrations, but interestingly, this did not occur.
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Affiliation(s)
- Douglas S Ramsay
- Department of Dental Public Health Sciences, University of Washington, Seattle, WA 98195-7475, USA
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Miller E, Mrowicka M, Malinowska K, Mrowicki J, Saluk-Juszczak J, Kędziora J. The effects of whole-body cryotherapy on oxidative stress in multiple sclerosis patients. J Therm Biol 2010. [DOI: 10.1016/j.jtherbio.2010.08.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Ceulemans AG, Zgavc T, Kooijman R, Hachimi-Idrissi S, Sarre S, Michotte Y. The dual role of the neuroinflammatory response after ischemic stroke: modulatory effects of hypothermia. J Neuroinflammation 2010; 7:74. [PMID: 21040547 PMCID: PMC2988764 DOI: 10.1186/1742-2094-7-74] [Citation(s) in RCA: 230] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Accepted: 11/01/2010] [Indexed: 12/15/2022] Open
Abstract
Neuroinflammation is a key element in the ischemic cascade after cerebral ischemia that results in cell damage and death in the subacute phase. However, anti-inflammatory drugs do not improve outcome in clinical settings suggesting that the neuroinflammatory response after an ischemic stroke is not entirely detrimental. This review describes the different key players in neuroinflammation and their possible detrimental and protective effects in stroke. Because of its inhibitory influence on several pathways of the ischemic cascade, hypothermia has been introduced as a promising neuroprotective strategy. This review also discusses the influence of hypothermia on the neuroinflammatory response. We conclude that hypothermia exerts both stimulating and inhibiting effects on different aspects of neuroinflammation and hypothesize that these effects are key to neuroprotection.
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Affiliation(s)
- An-Gaëlle Ceulemans
- Department of Pharmaceutical Chemistry and Drug Analysis, Research Group Experimental Neuropharmacology, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium
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Branco LGS, Bicego KC, Carnio EC, Pittman QJ. Gaseous neurotransmitters and their role in anapyrexia. Front Biosci (Elite Ed) 2010; 2:948-60. [PMID: 20515766 DOI: 10.2741/e154] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mammals keep their body temperature (Tb) relatively constant even under a wide range of ambient temperature variation. However, in some particular situations it may be beneficial to increase or to decrease Tb. For instance, under hypoxic conditions, a regulated drop in Tb (anapyrexia) takes place which has been reported to be crucial for survival in a number of different species. This review highlights major advances in the research about nitric oxide (NO) and carbon monoxide (CO- where data are relatively less abundant), before focusing on the role played by these gaseous neuromediators in thermoregulation, under the conditions of euthermia and anapyrexia. Available data are consistent with the notion that both NO and CO, acting on the CNS, participate in thermoregulation, with NO decreasing Tb and CO increasing it. However further studies are required before definitive conclusions can be made as to their physiological mechanisms of action.
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Affiliation(s)
- Luiz G S Branco
- Dental School of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil.
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43
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Role of preoptic opioid receptors in the body temperature reduction during hypoxia. Brain Res 2009; 1286:66-74. [DOI: 10.1016/j.brainres.2009.06.039] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2009] [Revised: 06/10/2009] [Accepted: 06/13/2009] [Indexed: 11/16/2022]
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Natah SS, Srinivasan S, Pittman Q, Zhao Z, Dunn JF. Effects of acute hypoxia and hyperthermia on the permeability of the blood-brain barrier in adult rats. J Appl Physiol (1985) 2009; 107:1348-56. [PMID: 19644026 DOI: 10.1152/japplphysiol.91484.2008] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Acute mountain sickness (AMS) develops within a few hours after arrival at high altitude and includes headache, anorexia, nausea, vomiting, and malaise. This afflicts 15-25% of the general tourist population at moderate altitudes. High-altitude cerebral edema (HACE) is considered to be the end stage of severe AMS and has been suggested to be a vasogenic edema, raising the possibility that acute hypoxia may increase blood-brain barrier (BBB) permeability. At present, there are no good small-animal models to study this syndrome. We hypothesize 1) that acute hypoxia can damage the BBB and 2) that rat can be used as a model to study hypoxia-induced changes in BBB permeability, especially if hypoxia-induced hypothermia could be minimized with high ambient temperature (HAT). Male Wistar rats were exposed to 1, 2, and 7 days of hypobaric hypoxia (equivalent to 0.5 atm), and changes in the temperature and BBB permeability were studied. The extravasation of endogenous immunoglobulin G, a large molecule, did not increase during room temperature hypoxia but did increase when hypoxia was combined with HAT. Hypoxia caused a significant increase in the leakage of sodium fluorescein (mol wt 376 Da). The expression of endothelial barrier antigen (EBA), a protein associated with the BBB, was reduced to 50% between 24 and 48 h after exposure to hypoxia, and the loss was exacerbated by HAT. The values almost returned to control levels by 7 days, showing adaptation to hypoxia. Hypoxic rats exhibited sodium fluorescein leakage mainly in focal areas in the brain parenchyma. In conclusion, it is possible to have transient BBB damage through exposure to acute hypoxia, and this damage is exacerbated by increasing body temperature to more of a normothermic value.
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Affiliation(s)
- Sirajedin S Natah
- Department of Radiology, University of Calgary, 3330 Hospital Dr., N.W., Calgary, Alberta T2N 4N1, Canada
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In vivo effects of 3-iodocytisine: pharmacological and genetic analysis of hypothermia and evaluation of chronic treatment on nicotinic binding sites. Neuropharmacology 2009; 57:332-42. [PMID: 19481555 DOI: 10.1016/j.neuropharm.2009.05.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2008] [Revised: 05/14/2009] [Accepted: 05/19/2009] [Indexed: 11/23/2022]
Abstract
Several cytisine derivatives have been developed in the search for more selective drugs at nicotinic acetylcholine receptors (nAChR). Binding experiments in transfected cell lines showed that the iodination of cytisine in the position 3 of the pyridone ring increased potency at alpha7-nAChR and to a lesser extent at the alpha4beta2 subtypes, both of which are widely expressed in the brain. However, no in vivo studies have been published on this compound. Inhibition curves presented here using wild type, beta2, and beta4-null mutant mice confirm that 3-IC binds to alpha4beta2 *, alpha7 * and alpha3beta4 * receptors with higher affinity than cytisine (asterisk indicates the receptor may contain additional subunits, Lukas et al., 1999). Intraperitoneal injection of 3-iodocytisine (3-IC) induced considerable dose-dependent hypothermia in DBA/2J and C57BL/6J mice. This response was blocked by mecamylamine and partially inhibited by hexamethonium. beta4-null mice displayed significantly less 3-IC-induced hypothermia than wild-type mice, beta2-null mice were somewhat less affected than wild types, while responses of alpha7 *-null mice were similar to wild types. Mice treated chronically with 3-IC display a marked increase in alpha7 * and alpha4beta2 * binding sites determined by radioligand binding in membrane preparations from cerebral cortex and hippocampus. Quantitative autoradiographic analysis of 28 brain regions of mice treated with 3-IC was consistent with the membrane binding, detecting an increase of cytisine-sensitive [(125)I]epibatidine binding sites, while cytisine-resistant [(125)I]epibatidine sites were unchanged. [(125)I]alpha-Bungarotoxin binding sites also exhibited up-regulation. These results give a first evaluation of in vivo consequences of 3-IC as a potent agonist with marked effects on mice.
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Lucas AD, Lappalainen SK, Wray-Cahen D. Hyperthermia increases the cytotoxicity of many exogenous compounds. Biomed Instrum Technol 2009; 43:73-9. [PMID: 19215178 DOI: 10.2345/0899-8205-43.1.73] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Cytotoxicity testing of extracts from medical device materials is typically conducted at 37 degrees C. It may be more relevant to screen extracts from device materials for in vitro cytotoxicity at temperatures found in febrile patients. To address this, the cytotoxicity of selected chemicals, drugs, and medical device extracts was evaluated in vitro following incubation at normothermic (37 degrees C) and hyperthermic (39 degrees C) conditions. In L929 cells, the percentage of cell death increased from 2-fold to more than 4-fold after chemical exposure when cells were maintained at 39 degrees C. Extracts of some medical devices and materials showed a 10-fold increase in cytotoxicity when cells were maintained at 39 degrees C as compared to 37 degrees C. For many of the substances in this study, exogenous compounds that are toxic at normothermic conditions (37 degrees C) are more cytotoxic under hyperthermic conditions (39 degrees C). The toxicity of compounds was more readily discernable at the higher incubation temperature, even at lower concentrations. In vitro cytotoxicity testing of chemicals and extracts at febrile temperatures can provide more sensitive and relevant biocompatibility tests than under normothermic conditions alone.
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Affiliation(s)
- Anne D Lucas
- US Food and Drug Administration, Center for Device and Radiological Health, Silver Spring, MD 20903, USA.
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47
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Guerra AR, Gargaglioni LH, Noronha-De-Souza CR, Abe AS, Branco LG, Bícego KC. Role of central nitric oxide in behavioral thermoregulation of toads during hypoxia. Physiol Behav 2008; 95:101-7. [DOI: 10.1016/j.physbeh.2008.05.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2008] [Accepted: 05/05/2008] [Indexed: 10/22/2022]
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Swoap SJ. The pharmacology and molecular mechanisms underlying temperature regulation and torpor. Biochem Pharmacol 2008; 76:817-24. [PMID: 18644349 DOI: 10.1016/j.bcp.2008.06.017] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2008] [Revised: 06/02/2008] [Accepted: 06/02/2008] [Indexed: 01/08/2023]
Abstract
The ability to enter a hypometabolic state upon restriction of caloric intake is pivotal for animal survival: balancing the energy budget in endotherms can be a real struggle when food is not available and/or the demand for heat production to maintain homeothermy becomes excessive. Bouts of torpor, characterized by metabolic rates well below a basal metabolic rate and core body temperatures that may be just a few degrees above the ambient temperature, are utilized among many organisms across the animal kingdom, including those that could be described as typical laboratory animals, like the mouse or hamster. Daily heterotherms, which are the focus of this commentary, enter shallow torpor bouts and do so usually under acute food shortage conditions and a relatively cool environment. Due to their small size, the body temperature of these animals is very responsive to food deprivation, pharmacological inhibition of metabolic rate, and cardiovascular depressants. This commentary examines recent developments concerning the neuroendocrine mechanisms in place that may mediate fasting-induced torpor in daily heterotherms. Further this commentary highlights pharmacological induction of hypothermia in small mammals.
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Affiliation(s)
- Steven J Swoap
- Department of Biology, Williams College, Williamstown, MA 01267, USA.
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Ueki S, Miyoshi M, Shido O, Hasegawa J, Watanabe T. Systemic administration of [6]-gingerol, a pungent constituent of ginger, induces hypothermia in rats via an inhibitory effect on metabolic rate. Eur J Pharmacol 2008; 584:87-92. [PMID: 18295202 DOI: 10.1016/j.ejphar.2008.01.031] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2007] [Revised: 01/09/2008] [Accepted: 01/24/2008] [Indexed: 10/22/2022]
Abstract
We investigated the effects of systemic administrations of ginger (Zingiber officinale Roscoe, Zingiberaceae) or its pungent constituent, [6]-gingerol, on resting body temperature in rats. Rats given ginger-containing rat chow for 5 days showed no changes in their day-night cycle of body temperature or physical activity. However, a single intraperitoneal (i.p.) injection of [6]-gingerol (2.5 or 25 mg/kg) induced a rapid, marked drop in body temperature in a dose-related manner, with no change in physical activity. A significant decrease in metabolic rate was observed immediately after an i.p. injection of [6]-gingerol (25 mg/kg), although heat-loss responses underwent no alteration (versus vehicle). These results suggest that in rats: (a) a decrease in metabolic rate is responsible for the [6]-gingerol-induced hypothermia, and (b) [6]-gingerol modulates or interferes with the mechanisms underlying body temperature regulation, while other bioactive constituents of ginger may counteract the hypothermic effect of [6]-gingerol.
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Affiliation(s)
- Shiori Ueki
- Department of Functional, Morphological and Regulatory Science, Tottori University Faculty of Medicine, Yonago, Tottori 683, Japan
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Abstract
Heat stroke is a life-threatening illness that affects all segments of society, including the young, aged, sick, and healthy. The recent high death toll in France (Dorozynski, 2003) and the death of high-profile athletes has increased public awareness of the adverse effects of heat injury. However, the etiology of the long-term consequences of this syndrome remains poorly understood such that preventive/treatment strategies are needed to mitigate its debilitating effects. Cytokines are important modulators of the acute phase response (APR) to stress, infection, and inflammation. Current data implicating cytokines in heat stroke responses are mainly from correlation studies showing elevated plasma levels in heat stroke patients and experimental animal models. Correlation data fall far short of revealing the mechanisms of cytokine actions such that additional research to determine the role of these endogenous substances in the heat stroke syndrome is required. Furthermore, cytokine determinations have occurred mainly at end-stage heat stroke, such that the role of these substances in progression and long-term recovery is poorly understood. Despite several studies implicating cytokines in heat stroke pathophysiology, few studies have examined the protective effect(s) of cytokine antagonism on the morbidity and mortality of heat stroke. This is particularly surprising since heat stroke responses resemble those observed in the endotoxemic syndrome, for which a role for endogenous cytokines has been strongly implicated. The implication of cytokines as mediators of endotoxemia and the presence of circulating endotoxin in heat stroke patients suggests that much knowledge can be gained from applying our current understanding of endotoxemic pathophysiology to the study of heat stroke. Heat shock proteins (HSPs) are highly conserved proteins that function as molecular chaperones for denatured proteins and reciprocally modulate cytokine production in response to stressful stimuli. HSPs have been shown repeatedly to confer protection in heat stroke and injury models. Interactions between HSPs and cytokines have received considerable attention in the literature within the last decade such that a complex pathway of interactions between cytokines, HSPs, and endotoxin is thought to be occurring in vivo in the orchestration of the APR to heat injury. These data suggest that much of the pathophysiologic changes observed with heat stroke are not a consequence of heat exposure, per se, but are representative of interactions among these three (and presumably additional) components of the innate immune response. This chapter will provide an overview of current knowledge regarding cytokine, HSP, and endotoxin interactions in heat stroke pathophysiology. Insight is provided into the potential therapeutic benefit of cytokine neutralization for mitigation of heat stroke morbidity and mortality based on our current understanding of their role in this syndrome.
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Affiliation(s)
- Lisa R Leon
- US Army Research Institute of Environmental Medicine, Thermal and Mountain Medicine Division, Natick, MA 01760-5007, USA.
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