1
|
Zhang Z, Wu X, Zou Z, Shen M, Liu Q, Zhangsun Z, Zhao H, Lei W, Wang Z, Dong Y, Yang Y. Heat Stroke: Pathogenesis, diagnosis, and current treatment. Ageing Res Rev 2024:102409. [PMID: 38986844 DOI: 10.1016/j.arr.2024.102409] [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: 02/05/2024] [Revised: 07/02/2024] [Accepted: 07/04/2024] [Indexed: 07/12/2024]
Abstract
Recently, the incidence of heat-related illnesses has exhibited a steadily upward trend, closely associated with several environmental factors such as climate change and air pollution. The progression of heat-related illnesses is a continuous process and can progress to the terminal period when it transforms into heat stroke, the most severe form. Heat stroke is markedly by a core body temperature above 40°C and central nervous system dysfunction. Current knowledge suggests that the pathogenesis of heat stroke is complex and varied, including inflammatory response, oxidative stress, cell death, and coagulation dysfunction. This review consolidated recent research progress on the pathophysiology and pathogenesis of heat stroke, with a focus on the related molecular mechanisms. In addition, we reviewed common strategies and sorted out the drugs in various preclinical stages for heat stroke, aiming to offer a comprehensive research roadmap for more in-depth researches into the mechanisms of heat stroke and the reduction in the mortality of heat stroke in the future.
Collapse
Affiliation(s)
- Zhe Zhang
- Xi'an Key Laboratory of Innovative Drug Research for Heart Failure, Northwest University First Hospital, Faculty of Life Sciences and Medicine, Northwest University, 229 Taibai North Road, Xi'an, China
| | - Xiaopeng Wu
- Xi'an Key Laboratory of Innovative Drug Research for Heart Failure, Northwest University First Hospital, Faculty of Life Sciences and Medicine, Northwest University, 229 Taibai North Road, Xi'an, China
| | - Zheng Zou
- Department of Neurosurgery, The General Hospital of Northern Theater Command, No. 83, Wenhua Road, Shenhe District, Shenyang, Liaoning 110016, China
| | - Mingzhi Shen
- Department of General Medicine, Hainan Hospital of Chinese PLA General Hospital, 80 Jianglin Road, Hainan, China
| | - Qiong Liu
- Xi'an Key Laboratory of Innovative Drug Research for Heart Failure, Northwest University First Hospital, Faculty of Life Sciences and Medicine, Northwest University, 229 Taibai North Road, Xi'an, China
| | - Ziyin Zhangsun
- Xi'an Key Laboratory of Innovative Drug Research for Heart Failure, Northwest University First Hospital, Faculty of Life Sciences and Medicine, Northwest University, 229 Taibai North Road, Xi'an, China
| | - Huadong Zhao
- Department of General Surgery, Tangdu Hospital, The Airforce Medical University, 1 Xinsi Road, Xi'an, China
| | - Wangrui Lei
- Xi'an Key Laboratory of Innovative Drug Research for Heart Failure, Northwest University First Hospital, Faculty of Life Sciences and Medicine, Northwest University, 229 Taibai North Road, Xi'an, China
| | - Zheng Wang
- Department of Cardiothoracic Surgery, Central Theater Command General Hospital of Chinese People's Liberation Army, 627 Wuluo Road, Wuhan, China
| | - Yushu Dong
- Department of Neurosurgery, The General Hospital of Northern Theater Command, No. 83, Wenhua Road, Shenhe District, Shenyang, Liaoning 110016, China.
| | - Yang Yang
- Xi'an Key Laboratory of Innovative Drug Research for Heart Failure, Northwest University First Hospital, Faculty of Life Sciences and Medicine, Northwest University, 229 Taibai North Road, Xi'an, China.
| |
Collapse
|
2
|
Wen J, Cheng J, Wang L, Li C, Zou Y, Wu J, Liu J. Dynamic molecular choreography induced by acute heat exposure in human males: a longitudinal multi-omics profiling study. Front Public Health 2024; 12:1384544. [PMID: 38813424 PMCID: PMC11135052 DOI: 10.3389/fpubh.2024.1384544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 05/02/2024] [Indexed: 05/31/2024] Open
Abstract
Introduction Extreme heat events caused by occupational exposure and heat waves are becoming more common. However, the molecular changes underlying the response to heat exposure in humans remain to be elucidated. Methods This study used longitudinal multi-omics profiling to assess the impact of acute heat exposure (50°C for 30 min) in 24 subjects from a mine rescue team. Intravenous blood samples were collected before acute heat exposure (baseline) and at 5 min, 30 min, 1 h, and 24 h after acute heat exposure (recovery). In-depth multi-omics profiling was performed on each sample, including plasma proteomics (untargeted) and metabolomics (untargeted). Results After data curation and annotation, the final dataset contained 2,473 analytes, including 478 proteins and 1995 metabolites. Time-series analysis unveiled an orchestrated molecular choreography of changes involving the immune response, coagulation, acid-base balance, oxidative stress, cytoskeleton, and energy metabolism. Further analysis through protein-protein interactions and network analysis revealed potential regulators of acute heat exposure. Moreover, novel blood-based analytes that predicted change in cardiopulmonary function after acute heat exposure were identified. Conclusion This study provided a comprehensive investigation of the dynamic molecular changes that underlie the complex physiological processes that occur in human males who undergo heat exposure. Our findings will help health impact assessment of extreme high temperature and inspire future mechanistic and clinical studies.
Collapse
Affiliation(s)
- Jirui Wen
- Department of Otolaryngology-Head and Neck Surgery, Deep Underground Space Medical Center, West China Hospital, Sichuan University, Guoxuexiang, Chengdu, China
- Jinping Deep Underground Frontier Science and Dark Matter Key Laboratory of Sichuan Province, Liangshan, China
- State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering, Sichuan University, Chengdu, China
| | - Juan Cheng
- Department of Otolaryngology-Head and Neck Surgery, Deep Underground Space Medical Center, West China Hospital, Sichuan University, Guoxuexiang, Chengdu, China
| | - Ling Wang
- Department of Otolaryngology-Head and Neck Surgery, Deep Underground Space Medical Center, West China Hospital, Sichuan University, Guoxuexiang, Chengdu, China
- Jinping Deep Underground Frontier Science and Dark Matter Key Laboratory of Sichuan Province, Liangshan, China
| | - Can Li
- Department of Otolaryngology-Head and Neck Surgery, Deep Underground Space Medical Center, West China Hospital, Sichuan University, Guoxuexiang, Chengdu, China
| | - Yuhao Zou
- Department of Otolaryngology-Head and Neck Surgery, Deep Underground Space Medical Center, West China Hospital, Sichuan University, Guoxuexiang, Chengdu, China
| | - Jiang Wu
- Department of Otolaryngology-Head and Neck Surgery, Deep Underground Space Medical Center, West China Hospital, Sichuan University, Guoxuexiang, Chengdu, China
- Jinping Deep Underground Frontier Science and Dark Matter Key Laboratory of Sichuan Province, Liangshan, China
- Med-X Center for Manufacturing, Sichuan University, Chengdu, China
| | - Jifeng Liu
- Department of Otolaryngology-Head and Neck Surgery, Deep Underground Space Medical Center, West China Hospital, Sichuan University, Guoxuexiang, Chengdu, China
- Jinping Deep Underground Frontier Science and Dark Matter Key Laboratory of Sichuan Province, Liangshan, China
| |
Collapse
|
3
|
Xie J, Wang L, Xu Y, Ma Y, Zhang L, Yin W, Huang Y. Exertional heat stroke-induced changes in gut microbiota cause cognitive impairment in mice. BMC Microbiol 2024; 24:134. [PMID: 38654189 PMCID: PMC11040997 DOI: 10.1186/s12866-024-03276-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 03/25/2024] [Indexed: 04/25/2024] Open
Abstract
BACKGROUND The incidence of exertional heat stroke (EHS) escalates during periods of elevated temperatures, potentially leading to persistent cognitive impairment postrecovery. Currently, effective prophylactic or therapeutic measures against EHS are nonexistent. METHODS The selection of days 14 and 23 postinduction for detailed examination was guided by TEM of neuronal cells and HE staining of intestinal villi and the hippocampal regions. Fecal specimens from the ileum and cecum at these designated times were analyzed for changes in gut microbiota and metabolic products. Bioinformatic analyses facilitated the identification of pivotal microbial species and metabolites. The influence of supplementing these identified microorganisms on behavioral outcomes and the expression of functional proteins within the hippocampus was subsequently assessed. RESULTS TEM analyses of neurons, coupled with HE staining of intestinal villi and the hippocampal region, indicated substantial recovery in intestinal morphology and neuronal injury on Day 14, indicating this time point for subsequent microbial and metabolomic analyses. Notably, a reduction in the Lactobacillaceae family, particularly Lactobacillus murinus, was observed. Functional annotation of 16S rDNA sequences suggested diminished lipid metabolism and glycan biosynthesis and metabolism in EHS models. Mice receiving this intervention (EHS + probiotics group) exhibited markedly reduced cognitive impairment and increased expression of BDNF/TrKB pathway molecules in the hippocampus during behavioral assessment on Day 28. CONCLUSION Probiotic supplementation, specifically with Lactobacillus spp., appears to mitigate EHS-induced cognitive impairment, potentially through the modulation of the BDNF/TrKB signaling pathway within the hippocampus, illustrating the therapeutic potential of targeting the gut-brain axis.
Collapse
Affiliation(s)
- Jiangang Xie
- Department of Interventional Vascular, Xi'an No.3 Hospital, the Affiliated Hospital of Northwest University, Xi'an, Shaanxi Province, 710018, China
| | - Linxiao Wang
- College of Life Sciences, Northwest University, Xi'an, 710127, China
| | - Yunyun Xu
- Department of Emergency, Xijing Hospital, Air Force Medical University, Xi'an, Shaanxi Province, 710000, China
| | - Yuexiang Ma
- Department of Emergency, Xijing Hospital, Air Force Medical University, Xi'an, Shaanxi Province, 710000, China
| | - Lingqin Zhang
- Department of Emergency, Xijing Hospital, Air Force Medical University, Xi'an, Shaanxi Province, 710000, China
| | - Wen Yin
- Department of Emergency, Xijing Hospital, Air Force Medical University, Xi'an, Shaanxi Province, 710000, China.
| | - Yang Huang
- Department of Emergency, Xijing Hospital, Air Force Medical University, Xi'an, Shaanxi Province, 710000, China.
| |
Collapse
|
4
|
Murray KO, Brant JO, Spradlin RA, Thome T, Laitano O, Ryan TE, Riva A, Kladde MP, Clanton TL. Exertional heat stroke causes long-term skeletal muscle epigenetic reprogramming, altered gene expression, and impaired satellite cell function in mice. Am J Physiol Regul Integr Comp Physiol 2024; 326:R160-R175. [PMID: 38047316 DOI: 10.1152/ajpregu.00226.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 11/26/2023] [Accepted: 11/26/2023] [Indexed: 12/05/2023]
Abstract
The effect of exertional heat stroke (EHS) exposure on skeletal muscles is incompletely understood. Muscle weakness is an early symptom of EHS but is not considered a major target of multiorgan injury. Previously, in a preclinical mouse model of EHS, we observed the vulnerability of limb muscles to a second EHS exposure, suggesting hidden processes contributing to declines in muscle resilience. Here, we evaluated the possible molecular origins of EHS-induced declines in muscle resilience. Female C57BL/6 mice [total n = 56; 28/condition, i.e., EHS and exercise control (EXC)] underwent forced wheel running at 37.5°C/40% relative humidity until symptom limitation (unconsciousness). EXC mice exercised identically at room temperature (22-23°C). After 1 mo of recovery, the following were assessed: 1) specific force and caffeine-induced contracture in soleus (SOL) and extensor digitorum longus (EDL) muscles; 2) transcriptome and DNA methylome responses in gastrocnemius (GAST); and 3) primary satellite cell function (proliferation and differentiation). There were no differences in specific force in either SOL or EDL from EXC. Only EHS solei exhibited lower caffeine sensitivity. EHS GAST exhibited higher RNA expression of genes encoding structural proteins of slow fibers, heat shock proteins, and myogenesis. A total of ∼2,500 differentially methylated regions of DNA that could potentially affect many cell functions were identified. Primary satellite cells exhibited suppressed proliferation rates but normal differentiation responses. Results demonstrate long-term changes in skeletal muscles 1 mo after EHS that could contribute to declines in muscle resilience. Skeletal muscle may join other, more recognized tissues considered vulnerable to long-term effects of EHS.NEW & NOTEWORTHY Exertional heat stroke (EHS) in mice induces long-term molecular and functional changes in limb muscle that could reflect a loss of "resilience" to further stress. The phenotype was characterized by altered caffeine sensitivity and suppressed satellite cell proliferative potential. This was accompanied by changes in gene expression and DNA methylation consistent with ongoing muscle remodeling and stress adaptation. We propose that EHS may induce a prolonged vulnerability of skeletal muscle to further stress or injury.
Collapse
Affiliation(s)
- Kevin O Murray
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, Florida, United States
| | - Jason O Brant
- Department of Biostatistics, University of Florida, Gainesville, Florida, United States
- University of Florida Health Cancer Center, University of Florida, Gainesville, Florida, United States
| | - Ray A Spradlin
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, Florida, United States
| | - Trace Thome
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, Florida, United States
| | - Orlando Laitano
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, Florida, United States
| | - Terence E Ryan
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, Florida, United States
| | - Alberto Riva
- University of Florida Health Cancer Center, University of Florida, Gainesville, Florida, United States
- Interdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, Florida, United States
| | - Michael P Kladde
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, Florida, United States
- University of Florida Health Cancer Center, University of Florida, Gainesville, Florida, United States
| | - Thomas L Clanton
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, Florida, United States
| |
Collapse
|
5
|
Hansson E, Broberg K, Wijkström J, Glaser J, Gonzalez-Quiroz M, Ekström U, Abrahamson M, Jakobsson K. An explorative study of inflammation-related proteins associated with kidney injury in male heat-stressed workers. J Therm Biol 2023; 112:103433. [PMID: 36796890 DOI: 10.1016/j.jtherbio.2022.103433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 11/12/2022] [Accepted: 12/15/2022] [Indexed: 01/22/2023]
Abstract
Chronic kidney disease of non-traditional origin (CKDnt) and acute kidney injury (AKI) often affect heat-stressed Mesoamerican manual workers. Inflammation occurs concurrently with AKI in this population, but its role remains unknown. To explore links between inflammation and kidney injury in heat stress, we compared levels of inflammation-related proteins in cutters with and without increasing serum creatinine levels during sugarcane harvest. These sugarcane cutters have previously been identified to be repeatedly exposed to severe heat stress during the five month harvest season. A nested case-control study was conducted among male Nicaraguan sugarcane cutters in a CKDnt hotspot. Cases (n = 30) were defined as having an increase in creatinine of ≥0.3 mg/dL across the five-month harvest. Controls (n = 57) had stable creatinine levels. Ninety-two inflammation-related proteins in serum were measured before and after harvest using Proximity Extension Assays. Mixed linear regression was used to identify differences in protein concentrations between cases and controls before harvest, differential trends during harvest, and association between protein concentrations and the urine kidney injury markers Kidney Injury Molecule (KIM)-1, Monocyte Chemoattractant Protein (MCP)-1 and albumin. One protein, chemokine (C-C motif) ligand 23 (CCL23), was elevated among cases at pre-harvest. Changes in seven inflammation-related proteins (CCL19, CCL23, colony-stimulating factor 1 [CSF1], hepatocyte and fibroblast growth factors [HGF and FGF23], and tumor necrosis factor beta [TNFB] and TNF-related activation-induced cytokine [TRANCE]) were associated with case status and at least two out of three urine kidney injury markers (KIM-1, MCP-1 and albumin). Several of these have been implicated in myofibroblast activation, which likely is an important step in kidney interstitial fibrotic disease such as CKDnt. This study provides an initial exploration of immune system determinants of, and activation during, kidney injury experienced during prolonged heat stress.
Collapse
Affiliation(s)
- Erik Hansson
- School of Public Health and Community Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Sweden; La Isla Network, Washington, D.C., USA.
| | - Karin Broberg
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden; Division of Occupational and Environmental Medicine, Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Julia Wijkström
- Division of Renal Medicine, Department of Clinical Science Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
| | | | - Marvin Gonzalez-Quiroz
- Department of Renal Medicine, University College London, London, United Kingdom; School of Medicine, Universidad Nacional de Chimborazo, Riobamba, Ecuador
| | - Ulf Ekström
- La Isla Network, Washington, D.C., USA; Division of Clinical Chemistry and Pharmacology, Department of Laboratory Medicine, Lund University, Sweden
| | - Magnus Abrahamson
- Division of Clinical Chemistry and Pharmacology, Department of Laboratory Medicine, Lund University, Sweden
| | - Kristina Jakobsson
- School of Public Health and Community Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Sweden; La Isla Network, Washington, D.C., USA
| |
Collapse
|
6
|
Yang J, Gong F, Shi X, Wang F, Qian J, Wan L, Chen Y, Chen H, Tong H. A nomogram based on lymphocyte percentage for predicting hospital mortality in exertional heatstroke patients: a 13-year retrospective study. World J Emerg Med 2023; 14:434-441. [PMID: 37969217 PMCID: PMC10632760 DOI: 10.5847/wjem.j.1920-8642.2023.101] [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: 04/07/2023] [Accepted: 07/28/2023] [Indexed: 11/17/2023] Open
Abstract
BACKGROUND Exertional heatstroke (EHS) is a life-threatening disease without ideal prognostic markers for predicting hospital mortality. METHODS This is a single-center retrospective study. Clinical data from EHS patients admitted to the Intensive Care Unit (ICU) of the General Hospital of Southern Theatre Command between January 1, 2008, and December 31, 2020, were recorded and analyzed. Univariate and multivariate logistic regression were used to identify the factors for mortality. The prediction model was developed with the prognostic markers, and a nomogram was established. RESULTS The study ultimately enrolled 156 patients, and 15 (9.6%) of patients died before discharge. The lymphocyte count (Lym) and percentage (Lym%) were significantly lower in non-survivors (P<0.05). The univariate and multivariate logistic regression analyses indicated that Lym% at the third day of admission (Lym% D3) (OR=0.609, 95%CI: 0.454-0.816) and hematocrit (HCT) (OR=0.908, 95%CI: 0.834-0.988) were independent protective factors for hospital mortality. A nomogram incorporating Lym% D3 with HCT was developed and demonstrated good discrimination and calibration ability. The comparison between the prediction model and scoring systems revealed that the prediction model had the largest area under the curve (AUC) (0.948, 95%CI: 0.900-0.977), with 100.00% sensitivity and 83.69% specificity, and a greater clinical net benefit. CONCLUSION Severe EHS patients had a higher risk of experiencing prolonged lymphopenia. A nomogram based on Lym% D3 and HCT was developed to facilitate early identification and timely treatment of patients with potentially unfavorable prognoses.
Collapse
Affiliation(s)
- Jiale Yang
- Guangzhou University of Chinese Medicine, Guangzhou 510006, China
- Department of Intensive Care Unit, General Hospital of Southern Theatre Command of PLA, Guangzhou 510010, China
| | - Fanghe Gong
- Department of Neurosurgery, General Hospital of Southern Theatre Command of PLA, Guangzhou 510010, China
| | - Xuezhi Shi
- Department of Intensive Care Unit, General Hospital of Southern Theatre Command of PLA, Guangzhou 510010, China
| | - Fanfan Wang
- Department of Intensive Care Unit, General Hospital of Southern Theatre Command of PLA, Guangzhou 510010, China
| | - Jing Qian
- Guangzhou University of Chinese Medicine, Guangzhou 510006, China
- Department of Intensive Care Unit, General Hospital of Southern Theatre Command of PLA, Guangzhou 510010, China
| | - Lulu Wan
- Guangzhou University of Chinese Medicine, Guangzhou 510006, China
- Department of Intensive Care Unit, General Hospital of Southern Theatre Command of PLA, Guangzhou 510010, China
| | - Yi Chen
- Department of Intensive Care Unit, Dongguan Binhaiwan Central Hospital, Dongguan 523900, China
| | - Huaisheng Chen
- Department of Critical Care Medicine, Shenzhen People’s Hospital, Shenzhen 518020, China
| | - Huasheng Tong
- Guangzhou University of Chinese Medicine, Guangzhou 510006, China
- Department of Intensive Care Unit, General Hospital of Southern Theatre Command of PLA, Guangzhou 510010, China
| |
Collapse
|
7
|
Oki K, Henderson CG, Ward SM, Ward JA, Plamper ML, Mayer TA, Caldwell AR, Leon LR. Identification of therapeutic targets in a murine model of severe exertional heat stroke. Am J Physiol Regul Integr Comp Physiol 2022; 323:R935-R950. [PMID: 36283086 PMCID: PMC9722257 DOI: 10.1152/ajpregu.00150.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 10/20/2022] [Accepted: 10/21/2022] [Indexed: 11/22/2022]
Abstract
Exertional heat stroke (EHS) is a potentially lethal condition resulting from high core body temperatures (TC) in combination with a systemic inflammatory response syndrome (SIRS) with varying degrees of severity across victims, and limited understanding of the underlying mechanism(s). We established a mouse model of severe EHS to identify mechanisms of hyperthermia/inflammation that may be responsible for organ damage. Mice were forced to run on a motorized wheel in a 37.5°C chamber until loss of consciousness and were either removed immediately (exertional heat injury or EHI; TCMax = 42.4 ± 0.2°C) or remained in the chamber an additional 20 min (EHS; TCMax = 42.5 ± 0.4°C). Exercise control mice (ExC) experienced identical procedures to EHS at 25°C. At 3 h post-EHS, there was evidence for an immune/inflammatory response as elevated blood chemokine [interferon γ-induced protein 10 (IP-10), keratinocytes-derived chemokine (KC), macrophage inflammatory proteins (MIP-1α), MIP-1β, MIP-2] and cytokine [granulocyte colony-stimulating factor (G-CSF), interleukins (IL-10), IL-6] levels peaked and were highest in EHS mice compared with EHI and ExC mice. Immunoblotting of organs susceptible to EHS damage indicated that several kinases were sensitive to stress associated with heat/inflammation and exercise; specifically, phosphorylation of liver c-Jun NH2-terminal kinase (JNK) at threonine 183/tyrosine 185 immediately (0 h) postheating related to heat illness severity. We have established a mouse EHS model, and JNK [or its downstream target(s)] could underlie EHS symptomatology, allowing the identification of molecular pathways or countermeasure targets to mitigate heat illness severity, enable complete recovery, and decrease overall EHS-related fatalities.
Collapse
Affiliation(s)
- Kentaro Oki
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Chloe G Henderson
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
- Oak Ridge Institute of Science and Education, Oak Ridge, Tennessee
| | - Shauna M Ward
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Jermaine A Ward
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Mark L Plamper
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Thomas A Mayer
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Aaron R Caldwell
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
- Oak Ridge Institute of Science and Education, Oak Ridge, Tennessee
| | - Lisa R Leon
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| |
Collapse
|
8
|
Alzahrani JM, Murray KO, Gambino BJ, Garcia CK, Sheikh LH, Cusack KJ, Laitano O, Clanton TL. Neuromotor deficits and altered physiological responses to repeated exertional heat stroke exposures in mice. Am J Physiol Regul Integr Comp Physiol 2022; 323:R951-R961. [PMID: 36279505 PMCID: PMC9722251 DOI: 10.1152/ajpregu.00152.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 10/20/2022] [Accepted: 10/20/2022] [Indexed: 11/22/2022]
Abstract
Exertional heat stroke (EHS) is a life-threatening illness that can lead to negative health outcomes. Using a "severe" preclinical mouse model of EHS, we tested the hypotheses that one EHS exposure results in altered susceptibility to a subsequent EHS and reduced neuromotor performance. Female C57BL/6 mice underwent two protocols, 2 wk apart, either an EHS trial (EHS) or a sham exercise control trial (EXC). For EHS, mice ran in a forced running wheel at 37.5°C/40% relative humidity until loss of consciousness, followed by a slow cooling protocol (2 h recovery at 37.5°C). EXC mice exercised equally but in ∼22°C. Mice were randomized into three groups: 1) EXC-EXC (two consecutive EXC, n = 6, 2) EHS-EXC (EHS followed by EXC, n = 5), and 3) EHS-EHS (repeated EHS, n = 9). Mice underwent noninvasive neuromotor and behavioral tests during recovery and isolated soleus force measurements at the end of recovery. At the first EHS, mice reached average peak core temperatures (Tc,max) of 42.4°C, (46% mortality). On the second EHS, average Tc,max was reduced by ∼0.7°C (P < 0.05; mortality 18%). After the first EHS, both EHS-EX and EHS-EHS showed significant reductions in maximum strength (24 h and 1 wk post). After the second EHS, strength, horizontal rotation, hindlimb tone, suspended hindlimb splay, trunk curl, and provoked biting continued to decline in the EHS-EHS group. In conclusion, exposure to a second EHS after 2 wk leads to increased exercise times in the heat, symptom limitation at a lower Tc,max, and greater deficits in neuromotor and behavioral function during recovery.
Collapse
Affiliation(s)
- Jamal M Alzahrani
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, Florida
| | - Kevin O Murray
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, Florida
| | - Bryce J Gambino
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, Florida
| | - Christian K Garcia
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, Florida
| | - Laila H Sheikh
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, Florida
| | - Kevin J Cusack
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, Florida
| | - Orlando Laitano
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, Florida
| | - Thomas L Clanton
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, Florida
| |
Collapse
|
9
|
Murray KO, Brant JO, Kladde MP, Clanton TL. Long-term epigenetic and metabolomic changes in the mouse ventricular myocardium after exertional heat stroke. Physiol Genomics 2022; 54:486-500. [PMID: 36215393 PMCID: PMC9705024 DOI: 10.1152/physiolgenomics.00147.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 10/03/2022] [Accepted: 10/04/2022] [Indexed: 12/15/2022] Open
Abstract
Evidence from human epidemiological studies suggests that exertional heat stroke (EHS) results in an elevated risk of long-term cardiovascular and systemic disease. Previous results using a preclinical mouse model of EHS demonstrated severe metabolic imbalances in ventricular myocardium developing at 9-14 days of recovery. Whether this resolves over time is unknown. We hypothesized that the long-term effects of EHS on the heart reflect retained maladaptive epigenetic responses. In this study, we evaluated genome-wide DNA methylation, RNA-Seq, and metabolomic profiles of the left ventricular myocardium in female C57BL/6 mice, 30 days after EHS (exercise in 37.5°C; n = 7-8), compared with exercise controls. EHS mice ran to loss of consciousness, reaching core temperatures of 42.4 ± 0.2°C. All mice recovered quickly. After 30 days, the left ventricles were rapidly frozen for DNA methyl sequencing, RNA-Seq, and untargeted metabolomics. Ventricular DNA from EHS mice revealed >13,000 differentially methylated cytosines (DMCs) and >900 differentially methylated regions (DMRs; ≥5 DMCs with ≤300 bp between each CpG). Pathway analysis using DMRs revealed alterations in genes regulating basic cell functions, DNA binding, transcription, and metabolism. Metabolomics and mRNA expression revealed modest changes that are consistent with a return to homeostasis. Methylation status did not predict RNA expression or metabolic state at 30 days. We conclude that EHS induces a sustained DNA methylation memory lasting over 30 days of recovery, but ventricular gene expression and metabolism return to a relative homeostasis at rest. Such long-lasting alterations to the DNA methylation landscape could alter responsiveness to environmental or clinical challenges later in life.
Collapse
Affiliation(s)
- Kevin O Murray
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, Florida
| | - Jason O Brant
- Department of Biostatistics, University of Florida, Gainesville, Florida
- University of Florida Health Cancer Center, University of Florida, Gainesville, Florida
| | - Michael P Kladde
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, Florida
- University of Florida Health Cancer Center, University of Florida, Gainesville, Florida
| | - Thomas L Clanton
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, Florida
| |
Collapse
|
10
|
Schlader ZJ, Davis MS, Bouchama A. Biomarkers of heatstroke-induced organ injury and repair. Exp Physiol 2022; 107:1159-1171. [PMID: 35654394 PMCID: PMC9529995 DOI: 10.1113/ep090142] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Accepted: 05/19/2022] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the topic of this review? The status and potential role of novel biological markers (biomarkers) that can help identify the patients at risk of organ injury or long-term complications following heatstroke. What advances does it highlight? Numerous biomarkers were identified related to many aspects of generalized heatstroke-induced cellular injury and tissue damage, and heatstroke-provoked cardiovascular, renal, cerebral, intestinal and skeletal muscle injury. No novel biomarkers were identified for liver or lung injury. ABSTRACT Classic and exertional heatstroke cause acute injury and damage across numerous organ systems. Moreover, heatstroke survivors may sustain long-term neurological, cardiovascular and renal complications with a persistent risk of death. In this context, biomarkers, defined as biological samples obtained from heatstroke patients, are needed to detect early organ injury, and predict outcomes to develop novel organ preservation therapeutic strategies. This narrative review provides preliminary insights that will guide the development and future utilization of these biomarkers. To this end, we have identified numerous biomarkers of widespread heatstroke-associated cellular injury, tissue damage and repair (extracellular heat shock proteins 72 and 60, high mobility group box protein 1, histone H3, and interleukin-1α), and other organ-specific biomarkers including those related to the cardiovascular system (cardiac troponin I, endothelium-derived factors, circulation endothelial cells, adhesion molecules, thrombomodulin and von Willebrand factor antigen), the kidneys (plasma and urinary neutrophil gelatinase-associated lipocalin), the intestines (intestinal fatty acid-binding protein 2), the brain (serum S100β and neuron-specific enolase) and skeletal muscle (creatine kinase, myoglobin). No specific biomarkers have been identified so far for liver or lung injury in heatstroke. Before translating the identified biomarkers into clinical practice, additional preclinical and clinical prospective studies are required to further understand their clinical utility, particularly for the biomarkers related to long-term post-heatstroke health outcomes.
Collapse
Affiliation(s)
- Zachary J. Schlader
- Department of Kinesiology, School of Public Health, Indiana University, Bloomington, IN, USA
| | - Michael S. Davis
- Department of Physiological Sciences, College of Veterinary Medicine, Oklahoma State University, Stillwater, OK, USA
| | - Abderrezak Bouchama
- Department of Experimental Medicine, King Abdullah International Medical Research Center, King Saud bin Abdulaziz University for Health Sciences, Ministry of National Guard — Health Affairs, Riyadh, Saudi Arabia
| |
Collapse
|
11
|
Murray KO, Clanton TL, Horowitz M. Epigenetic responses to heat: From adaptation to maladaptation. Exp Physiol 2022; 107:1144-1158. [PMID: 35413138 PMCID: PMC9529784 DOI: 10.1113/ep090143] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Accepted: 03/25/2022] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the topic of this review? This review outlines the history of research on epigenetic adaptations to heat exposure. The perspective taken is that adaptations reflect properties of hormesis, whereby low, repeated doses of heat induce adaptation (acclimation/acclimatization); whereas brief, life-threatening exposures can induce maladaptive responses. What advances does it highlight? The epigenetic mechanisms underlying acclimation/acclimatization comprise specific molecular programmes on histones that regulate heat shock proteins transcriptionally and protect the organism from subsequent heat exposures, even after long delays. The epigenetic signalling underlying maladaptive responses might rely, in part, on extensive changes in DNA methylation that are sustained over time and might contribute to later health challenges. ABSTRACT Epigenetics plays a strong role in molecular adaptations to heat by producing a molecular memory of past environmental exposures. Moderate heat, over long periods of time, induces an 'adaptive' epigenetic memory, resulting in a condition of 'resilience' to future heat exposures or cross-tolerance to other forms of toxic stress. In contrast, intense, life-threatening heat exposures, such as severe heat stroke, can result in a 'maladaptive' epigenetic memory that can place an organism at risk of later health complications. These cellular memories are coded by post-translational modifications of histones on the nucleosomes and/or by changes in DNA methylation. They operate by inducing changes in the level of gene transcription and therefore phenotype. The adaptive response to heat acclimation functions, in part, by facilitating transcription of essential heat shock proteins and exhibits a biphasic short programme (maintaining DNA integrity, followed by a long-term consolidation). The latter accelerates acclimation responses after de-acclimation. Although less studied, the maladaptive responses to heat stroke appear to be coded in long-lasting changes in DNA methylation near the promoter region of genes involved with basic cell function. Whether these memories are also encoded in histone modifications is not yet known. There is considerable evidence that both adaptive and maladaptive epigenetic responses to heat can be inherited, although most evidence comes from lower organisms. Future challenges include understanding the signalling mechanisms responsible and discovering new ways to promote adaptive responses while suppressing maladaptive responses to heat, as all life forms adapt to life on a warming planet.
Collapse
Affiliation(s)
- Kevin O. Murray
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, USA
| | - Thomas L. Clanton
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Michal Horowitz
- Laboratory of Environmental Physiology, Faculty of Dentistry, The Hebrew University of Jerusalem, Jerusalem, Israel
| |
Collapse
|
12
|
Laitano O, Clanton TL, Leon LR. Heat stroke: physiological challenges and breakthroughs. Exp Physiol 2022; 107:1109-1110. [PMID: 36178301 DOI: 10.1113/ep090566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 09/06/2022] [Indexed: 11/08/2022]
Affiliation(s)
- Orlando Laitano
- College of Health and Human Performance, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Thomas L Clanton
- College of Health and Human Performance, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Lisa R Leon
- College of Health and Human Performance, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| |
Collapse
|
13
|
Cramer MN, Gagnon D, Laitano O, Crandall CG. Human temperature regulation under heat stress in health, disease, and injury. Physiol Rev 2022; 102:1907-1989. [PMID: 35679471 PMCID: PMC9394784 DOI: 10.1152/physrev.00047.2021] [Citation(s) in RCA: 59] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 05/10/2022] [Accepted: 05/28/2022] [Indexed: 12/30/2022] Open
Abstract
The human body constantly exchanges heat with the environment. Temperature regulation is a homeostatic feedback control system that ensures deep body temperature is maintained within narrow limits despite wide variations in environmental conditions and activity-related elevations in metabolic heat production. Extensive research has been performed to study the physiological regulation of deep body temperature. This review focuses on healthy and disordered human temperature regulation during heat stress. Central to this discussion is the notion that various morphological features, intrinsic factors, diseases, and injuries independently and interactively influence deep body temperature during exercise and/or exposure to hot ambient temperatures. The first sections review fundamental aspects of the human heat stress response, including the biophysical principles governing heat balance and the autonomic control of heat loss thermoeffectors. Next, we discuss the effects of different intrinsic factors (morphology, heat adaptation, biological sex, and age), diseases (neurological, cardiovascular, metabolic, and genetic), and injuries (spinal cord injury, deep burns, and heat stroke), with emphasis on the mechanisms by which these factors enhance or disturb the regulation of deep body temperature during heat stress. We conclude with key unanswered questions in this field of research.
Collapse
Affiliation(s)
- Matthew N Cramer
- Defence Research and Development Canada-Toronto Research Centre, Toronto, Ontario, Canada
| | - Daniel Gagnon
- Montreal Heart Institute and School of Kinesiology and Exercise Science, Université de Montréal, Montréal, Quebec, Canada
| | - Orlando Laitano
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Craig G Crandall
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, Texas
| |
Collapse
|
14
|
Bouchama A, Abuyassin B, Lehe C, Laitano O, Jay O, O'Connor FG, Leon LR. Classic and exertional heatstroke. Nat Rev Dis Primers 2022; 8:8. [PMID: 35115565 DOI: 10.1038/s41572-021-00334-6] [Citation(s) in RCA: 120] [Impact Index Per Article: 60.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/20/2021] [Indexed: 12/28/2022]
Abstract
In the past two decades, record-breaking heatwaves have caused an increasing number of heat-related deaths, including heatstroke, globally. Heatstroke is a heat illness characterized by the rapid rise of core body temperature above 40 °C and central nervous system dysfunction. It is categorized as classic when it results from passive exposure to extreme environmental heat and as exertional when it develops during strenuous exercise. Classic heatstroke occurs in epidemic form and contributes to 9-37% of heat-related fatalities during heatwaves. Exertional heatstroke sporadically affects predominantly young and healthy individuals. Under intensive care, mortality reaches 26.5% and 63.2% in exertional and classic heatstroke, respectively. Pathological studies disclose endothelial cell injury, inflammation, widespread thrombosis and bleeding in most organs. Survivors of heatstroke may experience long-term neurological and cardiovascular complications with a persistent risk of death. No specific therapy other than rapid cooling is available. Physiological and morphological factors contribute to the susceptibility to heatstroke. Future research should identify genetic factors that further describe individual heat illness risk and form the basis of precision-based public health response. Prioritizing research towards fundamental mechanism and diagnostic biomarker discovery is crucial for the design of specific management approaches.
Collapse
Affiliation(s)
- Abderrezak Bouchama
- King Abdullah International Medical Research Center, Experimental Medicine Department, King Saud bin Abdulaziz University for Health Sciences, Ministry of National Guard - Health Affairs, Riyadh, Saudi Arabia.
| | - Bisher Abuyassin
- King Abdullah International Medical Research Center, Experimental Medicine Department, King Saud bin Abdulaziz University for Health Sciences, Ministry of National Guard - Health Affairs, Riyadh, Saudi Arabia
| | - Cynthia Lehe
- King Abdullah International Medical Research Center, Experimental Medicine Department, King Saud bin Abdulaziz University for Health Sciences, Ministry of National Guard - Health Affairs, Riyadh, Saudi Arabia
| | - Orlando Laitano
- Department of Nutrition & Integrative Physiology, College of Health and Human Sciences, Florida State University, Tallahassee, FL, USA
| | - Ollie Jay
- Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
| | - Francis G O'Connor
- Military and Emergency Medicine, Uniformed Services University, Bethesda, MD, USA
| | - Lisa R Leon
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| |
Collapse
|
15
|
Garcia CK, Renteria LI, Leite-Santos G, Leon LR, Laitano O. Exertional heat stroke: pathophysiology and risk factors. BMJ MEDICINE 2022; 1:e000239. [PMID: 36936589 PMCID: PMC9978764 DOI: 10.1136/bmjmed-2022-000239] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 09/06/2022] [Indexed: 12/31/2022]
Abstract
Exertional heat stroke, the third leading cause of mortality in athletes during physical activity, is the most severe manifestation of exertional heat illnesses. Exertional heat stroke is characterised by central nervous system dysfunction in people with hyperthermia during physical activity and can be influenced by environmental factors such as heatwaves, which extend the incidence of exertional heat stroke beyond athletics only. Epidemiological data indicate mortality rates of about 27%, and survivors display long term negative health consequences ranging from neurological to cardiovascular dysfunction. The pathophysiology of exertional heat stroke involves thermoregulatory and cardiovascular overload, resulting in severe hyperthermia and subsequent multiorgan injury due to a systemic inflammatory response syndrome and coagulopathy. Research about risk factors for exertional heat stroke remains limited, but dehydration, sex differences, ageing, body composition, and previous illness are thought to increase risk. Immediate cooling remains the most effective treatment strategy. In this review, we provide an overview of the current literature emphasising the pathophysiology and risk factors of exertional heat stroke, highlighting gaps in knowledge with the objective to stimulate future research.
Collapse
Affiliation(s)
- Christian K Garcia
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Liliana I Renteria
- Department of Nutrition and Integrative Physiology, Florida State University, Tallahassee, FL, USA
| | - Gabriel Leite-Santos
- Department of Nutrition and Integrative Physiology, Florida State University, Tallahassee, FL, USA
| | - Lisa R Leon
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Orlando Laitano
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| |
Collapse
|
16
|
Langan SP, Szymanski MR, Casa DJ. (Can) what does not kill you make you stronger (?). J Appl Physiol (1985) 2021; 131:1850-1851. [PMID: 34898291 DOI: 10.1152/japplphysiol.00741.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Sean P Langan
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, Connecticut
| | - Michael R Szymanski
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, Connecticut
| | - Douglas J Casa
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, Connecticut
| |
Collapse
|
17
|
Caldwell AR, Oki K, Ward SM, Ward JA, Mayer TA, Plamper ML, King MA, Leon LR. Impact of successive exertional heat injuries on thermoregulatory and systemic inflammatory responses in mice. J Appl Physiol (1985) 2021; 131:1469-1485. [PMID: 34528459 DOI: 10.1152/japplphysiol.00160.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The purpose of the study was to determine if repeated exertional heat injuries (EHIs) worsen the inflammatory response. We assessed the impact of a single EHI bout (EHI0) or two separate EHI episodes separated by 1 (EHI1), 3 (EHI3), and 7 (EHI7) days in male C57BL/6J mice (n = 236). To induce EHI, mice underwent a forced running protocol until loss of consciousness or core temperature reached ≥ 42.7°C. Blood and tissue samples were obtained 30 min, 3 h, 1 day, or 7 days after the EHI. We observed that mice undergoing repeated EHI (EHI1, EHI3, and EHI7) had longer running distances before collapse (∼528 m), tolerated higher core temperatures (∼0.18°C higher) before collapse, and had higher minimum core temperature (indicative of injury severity) during recovery relative to EHI0 group (∼2.18°C higher; all P < 0.05). Heat resilience was most pronounced when latency was shortest between EHI episodes (i.e., thermal load and running duration highest in EHI1), suggesting the response diminishes with longer recoveries between EHI events. Furthermore, mice experiencing a second EHI exhibited increased serum and liver HSP70, and lower corticosterone, FABP2, MIP-1β, MIP-2, and IP-10 relative to mice experiencing a single EHI typically at 30 min to 3 h after EHI. Our findings indicate that an EHI event may initiate some adaptive processes that provide acute heat resilience to subsequent EHI conditions. NEW & NOTEWORTHY Mice undergoing repeated exertional heat injuries, within 1 wk of an initial heat injury, appear to have some protective adaptations. During the second exertional heat injury, mice were able to run longer and sustain higher body temperatures before collapse. Despite this, the mice undergoing a second exertional heat injury were more resilient to the heat as evidenced by attenuated minimum body temperature, higher HPS70 (serum and liver), lower corticosterone, and lower FABP2.
Collapse
Affiliation(s)
- Aaron R Caldwell
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts.,Oak Ridge Institute of Science and Education, Oak Ridge, Tennessee
| | - Kentaro Oki
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Shauna M Ward
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Jermaine A Ward
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Thomas A Mayer
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts.,Oak Ridge Institute of Science and Education, Oak Ridge, Tennessee
| | - Mark L Plamper
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Michelle A King
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Lisa R Leon
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| |
Collapse
|
18
|
Roberts WO, Armstrong LE, Sawka MN, Yeargin SW, Heled Y, O'Connor FG. ACSM Expert Consensus Statement on Exertional Heat Illness: Recognition, Management, and Return to Activity. Curr Sports Med Rep 2021; 20:470-484. [PMID: 34524191 DOI: 10.1249/jsr.0000000000000878] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
ABSTRACT Exertional heat stroke (EHS) is a true medical emergency with potential for organ injury and death. This consensus statement emphasizes that optimal exertional heat illness management is promoted by a synchronized chain of survival that promotes rapid recognition and management, as well as communication between care teams. Health care providers should be confident in the definitions, etiologies, and nuances of exertional heat exhaustion, exertional heat injury, and EHS. Identifying the athlete with suspected EHS early in the course, stopping activity (body heat generation), and providing rapid total body cooling are essential for survival, and like any critical life-threatening situation (cardiac arrest, brain stroke, sepsis), time is tissue. Recovery from EHS is variable, and outcomes are likely related to the duration of severe hyperthermia. Most exertional heat illnesses can be prevented with the recognition and modification of well-described risk factors ideally addressed through leadership, policy, and on-site health care.
Collapse
Affiliation(s)
- William O Roberts
- Department of Family Medicine and Community Health, University of Minnesota Medical School, Minneapolis, MN
| | | | - Michael N Sawka
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA
| | - Susan W Yeargin
- Department of Exercise Science, University of South Carolina, Columbia, SC
| | - Yuval Heled
- Clinical and Integrative Physiology Unit, Heller Institute of Medical Research, Sheba Medical Center, ISRAEL
| | - Francis G O'Connor
- Consortium for Health and Military Performance, Uniformed Services University of the Health Sciences, Bethesda, MD
| |
Collapse
|
19
|
Weinhouse C. The roles of inducible chromatin and transcriptional memory in cellular defense system responses to redox-active pollutants. Free Radic Biol Med 2021; 170:85-108. [PMID: 33789123 PMCID: PMC8382302 DOI: 10.1016/j.freeradbiomed.2021.03.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 03/12/2021] [Accepted: 03/15/2021] [Indexed: 12/17/2022]
Abstract
People are exposed to wide range of redox-active environmental pollutants. Air pollution, heavy metals, pesticides, and endocrine disrupting chemicals can disrupt cellular redox status. Redox-active pollutants in our environment all trigger their own sets of specific cellular responses, but they also activate a common set of general stress responses that buffer the cell against homeostatic insults. These cellular defense system (CDS) pathways include the heat shock response, the oxidative stress response, the hypoxia response, the unfolded protein response, the DNA damage response, and the general stress response mediated by the stress-activated p38 mitogen-activated protein kinase. Over the past two decades, the field of environmental epigenetics has investigated epigenetic responses to environmental pollutants, including redox-active pollutants. Studies of these responses highlight the role of chromatin modifications in controlling the transcriptional response to pollutants and the role of transcriptional memory, often referred to as "epigenetic reprogramming", in predisposing previously exposed individuals to more potent transcriptional responses on secondary challenge. My central thesis in this review is that high dose or chronic exposure to redox-active pollutants leads to transcriptional memories at CDS target genes that influence the cell's ability to mount protective responses. To support this thesis, I will: (1) summarize the known chromatin features required for inducible gene activation; (2) review the known forms of transcriptional memory; (3) discuss the roles of inducible chromatin and transcriptional memory in CDS responses that are activated by redox-active environmental pollutants; and (4) propose a conceptual framework for CDS pathway responsiveness as a readout of total cellular exposure to redox-active pollutants.
Collapse
Affiliation(s)
- Caren Weinhouse
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, 97214, USA.
| |
Collapse
|
20
|
Incidence of Recurrent Exertional Heat Stroke in a Warm-Weather Road Race. ACTA ACUST UNITED AC 2020; 56:medicina56120720. [PMID: 33371206 PMCID: PMC7766530 DOI: 10.3390/medicina56120720] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 12/15/2020] [Accepted: 12/17/2020] [Indexed: 12/27/2022]
Abstract
Background and Objectives: Exertional heat stroke (EHS) survivors may be more susceptible to subsequent EHS; however, the occurrence of survivors with subsequent EHS episodes is limited. Therefore, the purpose of this study was to evaluate the incidence of participants with repeated EHS (EHS-2+) cases in a warm-weather road race across participation years compared to those who experienced 1 EHS (EHS-1). Materials and Methods: A retrospective observational case series design was utilized. Medical record data from 17-years at the Falmouth Road Race between 2003–2019 were examined for EHS cases. Incidence of EHS-2+ cases per race and average EHS cases per EHS-2+ participant were calculated (mean ± SD) and descriptive factors (rectal temperature (TRE), finish time (FT), Wet Bulb Globe Temperature (WBGT), age, race year) for each EHS was collected. Results: A total of 333 EHS patients from 174,853 finishers were identified. Sixteen EHS-2+ participants (11 males, 5 females, age = 39 ± 16 year) accounted for 11% of the total EHS cases (n = 37/333). EHS-2+ participants had an average of 2.3 EHS cases per person (range = 2–4) and had an incidence rate of 2.6 EHS per 10 races. EHS-2+ participants finished 93 races following initial EHS, with 72 of the races (77%) completed without EHS incident. Initial EHS TRE was not statistically different than subsequent EHS initial TRE (+0.3 ± 0.9 °C, p > 0.050). Initial EHS-2+ participant FT was not statistically different than subsequent EHS FT (−4.2 ± 7.0 min, p > 0.050). The years between first and second EHS was 3.6 ± 3.5 year (Mode: 1, Range: 1–12). Relative risk ratios revealed that EHS patients were at a significantly elevated risk for subsequent EHS episodes 2 years following their initial EHS (relative risk ratio = 3.32, p = 0.050); however, the risk from 3–5 years post initial EHS was not statistically elevated, though the relative risk ratio values remained above 1.26. Conclusions: These results demonstrate that 11% of all EHS cases at the Falmouth Road Race are EHS-2+ cases and that future risk for a second EHS episode at this race is most likely to occur within the first 2 years following the initial EHS incident. After this initial 2-year period, risk for another EHS episode is not significantly elevated. Future research should examine factors to explain individuals who are susceptible to multiple EHS cases, incidence at other races and corresponding prevention strategies both before and after initial EHS.
Collapse
|
21
|
Woods SE. Immunosuppression is associated with epigenetic remodelling in a murine model of exertional heat stroke. J Physiol 2020; 599:1373-1374. [PMID: 33210295 DOI: 10.1113/jp280949] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Affiliation(s)
- Siobhan E Woods
- Human Health and Nutritional Sciences, University of Guelph, Guelph, Canada
| |
Collapse
|
22
|
Horowitz M. Do exertional heat stroke and environmental heat involve epigenetic memory? J Physiol 2020; 599:7-8. [PMID: 33098309 DOI: 10.1113/jp280928] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Michal Horowitz
- Laboratory of Environmental Physiology, The Hebrew University of Jerusalem, Jerusalem, Israel
| |
Collapse
|