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Cui F, Mi H, Wang R, Du Y, Li F, Chang S, Su Y, Liu A, Shi M. The effect of chronic intermittent hypobaric hypoxia improving liver damage in metabolic syndrome rats through ferritinophagy. Pflugers Arch 2023; 475:1251-1263. [PMID: 37747537 DOI: 10.1007/s00424-023-02860-6] [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: 05/18/2023] [Revised: 08/31/2023] [Accepted: 09/12/2023] [Indexed: 09/26/2023]
Abstract
Studies have confirmed that hepatic iron overload is one of the important factors causing liver damage in the metabolic syndrome (MS). As a special form of autophagy, ferritinophagy is involved in the regulation of iron metabolism. Our previous studies have shown that chronic intermittent hypobaric hypoxia (CIHH) can improve the iron metabolism disorder. The aim of this study was to investigate how CIHH improves liver damage through ferritinophagy in MS rats. Male Sprague-Dawley rats aged 8-10 weeks were randomly divided into four groups: control (CON), CIHH (exposed to hypoxia at a simulated altitude of 5000 m for 28 days, 6 h daily), MS model (induced by a 16-week high-fat diet and 10% fructose water feeding), and MS + CIHH (exposed to CIHH after a 16-week MS inducement) groups. Liver index, liver function, iron content, tissue morphology, oxidative stress, ferritinophagy, ferroptosis, and iron metabolism-related protein expression were measured, and the ferritinophagy flux in the liver was further analyzed. Compared with CON rats, MS rats had an increased liver index, damaged liver tissue and function, increased iron content and iron deposition, disrupted iron metabolism, significantly increased oxidative stress indicators in the liver, significantly upregulated expression of ferroptosis-related proteins, and downregulated expression of nuclear receptor coactivator 4 (NCOA4) and ferritinophagy flux. After CIHH treatment, the degree of liver damage and various abnormal indicators in MS rats were significantly improved. CIHH may improve liver damage by promoting NCOA4-mediated ferritinophagy, reducing iron overload and oxidative stress, and thereby alleviating ferroptosis in MS rats.
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Affiliation(s)
- Fang Cui
- Department of Clinical Laboratory, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei Province, 050000, People's Republic of China
- Department of Electron Microscope Laboratory, Hebei Medical University, Shijiazhuang, 050017, People's Republic of China
| | - Haichao Mi
- Department of Clinical Laboratory, Linyi People's Hospital, Linyi, 276003, People's Republic of China
| | - Ruotong Wang
- Department of Clinical Laboratory, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei Province, 050000, People's Republic of China
| | - Yutao Du
- Department of Clinical Laboratory, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei Province, 050000, People's Republic of China
| | - Fan Li
- Department of Pathology, Hebei Medical University, Shijiazhuang, 050017, People's Republic of China
| | - Shiyang Chang
- Department of Histology and Embryology, Hebei Medical University, Shijiazhuang, 050017, People's Republic of China
| | - Yangchen Su
- College of Basic Medicine, Hebei Medical University, Shijiazhuang, 050017, People's Republic of China
| | - Aijing Liu
- Department of Rheumatology and Immunology, The Second Hospital of Hebei Medical University, Shijiazhuang, 050000, People's Republic of China
| | - Min Shi
- Department of Clinical Laboratory, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei Province, 050000, People's Republic of China.
- Hebei Key Laboratory of Laboratory Medicine, Shijiazhuang, 050017, People's Republic of China.
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Burtscher J, Citherlet T, Camacho-Cardenosa A, Camacho-Cardenosa M, Raberin A, Krumm B, Hohenauer E, Egg M, Lichtblau M, Müller J, Rybnikova EA, Gatterer H, Debevec T, Baillieul S, Manferdelli G, Behrendt T, Schega L, Ehrenreich H, Millet GP, Gassmann M, Schwarzer C, Glazachev O, Girard O, Lalande S, Hamlin M, Samaja M, Hüfner K, Burtscher M, Panza G, Mallet RT. Mechanisms underlying the health benefits of intermittent hypoxia conditioning. J Physiol 2023. [PMID: 37860950 DOI: 10.1113/jp285230] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Accepted: 10/11/2023] [Indexed: 10/21/2023] Open
Abstract
Intermittent hypoxia (IH) is commonly associated with pathological conditions, particularly obstructive sleep apnoea. However, IH is also increasingly used to enhance health and performance and is emerging as a potent non-pharmacological intervention against numerous diseases. Whether IH is detrimental or beneficial for health is largely determined by the intensity, duration, number and frequency of the hypoxic exposures and by the specific responses they engender. Adaptive responses to hypoxia protect from future hypoxic or ischaemic insults, improve cellular resilience and functions, and boost mental and physical performance. The cellular and systemic mechanisms producing these benefits are highly complex, and the failure of different components can shift long-term adaptation to maladaptation and the development of pathologies. Rather than discussing in detail the well-characterized individual responses and adaptations to IH, we here aim to summarize and integrate hypoxia-activated mechanisms into a holistic picture of the body's adaptive responses to hypoxia and specifically IH, and demonstrate how these mechanisms might be mobilized for their health benefits while minimizing the risks of hypoxia exposure.
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Affiliation(s)
- Johannes Burtscher
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Tom Citherlet
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Alba Camacho-Cardenosa
- Department of Physical Education and Sports, Faculty of Sports Science, Sport and Health University Research Institute (iMUDS), University of Granada, Granada, Spain
| | - Marta Camacho-Cardenosa
- Clinical Management Unit of Endocrinology and Nutrition - GC17, Maimónides Biomedical Research Institute of Cordoba (IMIBIC), Reina Sofía University Hospital, Córdoba, Spain
| | - Antoine Raberin
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Bastien Krumm
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Erich Hohenauer
- Rehabilitation and Exercise Science Laboratory (RES lab), Department of Business Economics, Health and Social Care, University of Applied Sciences and Arts of Southern Switzerland, Landquart, Switzerland
- International University of Applied Sciences THIM, Landquart, Switzerland
- Department of Neurosciences and Movement Science, University of Fribourg, Fribourg, Switzerland
| | - Margit Egg
- Institute of Zoology, University of Innsbruck, Innsbruck, Austria
| | - Mona Lichtblau
- Department of Pulmonology, University Hospital Zurich, Zurich, Switzerland
- University of Zurich, Zurich, Switzerland
| | - Julian Müller
- Department of Pulmonology, University Hospital Zurich, Zurich, Switzerland
- University of Zurich, Zurich, Switzerland
| | - Elena A Rybnikova
- Pavlov Institute of Physiology, Russian Academy of Sciences, St Petersburg, Russia
| | - Hannes Gatterer
- Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
- Institute for Sports Medicine, Alpine Medicine and Health Tourism (ISAG), UMIT TIROL-Private University for Health Sciences and Health Technology, Hall in Tirol, Austria
| | - Tadej Debevec
- Faculty of Sport, University of Ljubljana, Ljubljana, Slovenia
- Department of Automatics, Biocybernetics and Robotics, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Sebastien Baillieul
- Service Universitaire de Pneumologie Physiologie, University of Grenoble Alpes, Inserm, Grenoble, France
| | | | - Tom Behrendt
- Chair Health and Physical Activity, Department of Sport Science, Institute III, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Lutz Schega
- Chair Health and Physical Activity, Department of Sport Science, Institute III, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Hannelore Ehrenreich
- Clinical Neuroscience, University Medical Center and Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Grégoire P Millet
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Max Gassmann
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zürich, Zurich, Switzerland
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
- Universidad Peruana Cayetano Heredia (UPCH), Lima, Peru
| | - Christoph Schwarzer
- Institute of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Oleg Glazachev
- Department of Normal Physiology, N.V. Sklifosovsky Institute of Clinical Medicine, I. M. Sechenov First Moscow State Medical University, Moscow, Russia
| | - Olivier Girard
- School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Crawley, Western Australia, Australia
| | - Sophie Lalande
- Department of Kinesiology and Health Education, University of Texas at Austin, Austin, TX, USA
| | - Michael Hamlin
- Department of Tourism, Sport and Society, Lincoln University, Christchurch, New Zealand
| | - Michele Samaja
- Department of Health Science, University of Milan, Milan, Italy
| | - Katharina Hüfner
- Department of Psychiatry, Psychotherapy, Psychosomatics and Medical Psychology, University Hospital for Psychiatry II, Medical University of Innsbruck, Innsbruck, Austria
| | - Martin Burtscher
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Gino Panza
- The Department of Health Care Sciences, Program of Occupational Therapy, Wayne State University, Detroit, MI, USA
- John D. Dingell VA Medical Center Detroit, Detroit, MI, USA
| | - Robert T Mallet
- Department of Physiology & Anatomy, University of North Texas Health Science Center, Fort Worth, TX, USA
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Sharafkhaneh A, Agrawal R, Nambi V, BaHammam A, Razjouyan J. Obesity paradox or hypoxia preconditioning: How obstructive sleep apnea modifies the Obesity-MI relationship. Sleep Med 2023; 110:132-136. [PMID: 37574613 PMCID: PMC10529841 DOI: 10.1016/j.sleep.2023.07.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 07/17/2023] [Accepted: 07/27/2023] [Indexed: 08/15/2023]
Abstract
OBJECTIVES The objective of this study was to evaluate the interaction between obesity and obstructive sleep apnea on acute MI in hospital mortality. METHODS This retrospective cohort study utilized Veterans Health Administration data from years 1999-2020. Participants were categorized according to their body mass index (BMI) to non-obese (BMI <30) and obese (BMI ≥30) groups. Clinical obstructive sleep apnea (SA) diagnosis was confirmed using ICD9/10 codes and the study subgroups included non-obese with no obstructive sleep apnea (nOB-nSA), non-Obese with obstructive sleep apnea (nOB-SA), obese with no obstructive sleep apnea (OB-nSA), and obese with obstructive sleep apnea (OB-SA). The primary outcome was odds ratio of in-hospital mortality during the hospitalization with acute MI as the principal diagnosis adjusted for age, gender, race, ethnicity, and Charlson comorbidity index (CCI) with the nOB-nSA group as the comparison group. RESULTS Among 72,036 veterans with acute-MI hospitalization, individuals with obesity and obstructive sleep apnea (OB-SA) had the lowest in-hospital mortality rate (1.0%) compared to those without obesity and obstructive sleep apnea (nOB-nSA, 2.8%), with obesity but without obstructive sleep apnea (OB-nSA, 2.4%), and with obesity and obstructive sleep apnea (nOB-SA, 1.4%). The adjusted odds ratio for mortality, compared to nOB-nSA, was 9% higher but not significant in OB-nSA (aOR, 1.09, 95%CI: 0.95, 1.25), 46% lower in OB-nSA (aOR, 0.54, 95%CI: 0.45, 0.66), and 52% lower in OB-SA (aOR, 0.48: 95%CI: 0.41, 0.57). CONCLUSION Our data suggest that the association between obesity and improved survival in acute MI is largely driven by the presence of sleep apnea.
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Affiliation(s)
- Amir Sharafkhaneh
- Department of Medicine, Baylor College of Medicine, Houston, TX, USA; Pulmonary, Critical Care and Sleep Medicine Section, Medical Care Line, Michael E. DeBakey VA Medical Center, Houston, TX, USA.
| | - Ritwick Agrawal
- Department of Medicine, Baylor College of Medicine, Houston, TX, USA; Pulmonary, Critical Care and Sleep Medicine Section, Medical Care Line, Michael E. DeBakey VA Medical Center, Houston, TX, USA
| | - Vijay Nambi
- Department of Medicine, Baylor College of Medicine, Houston, TX, USA; Cardiology Section, Medical Care Line, Michael E. DeBakey VA Medical Center, Houston, TX, USA
| | - Ahmed BaHammam
- Department of Medicine, University Sleep Disorders Center and Pulmonary Service, King Saud University, Riyadh, Saudi Arabia; Strategic Technologies Program of the National Plan for Sciences and Technology and Innovation in the Kingdom of Saudi Arabia, Saudi Arabia
| | - Javad Razjouyan
- Department of Medicine, Baylor College of Medicine, Houston, TX, USA; Center for Innovations in Quality, Effectiveness, and Safety, Michael E. DeBakey VA Medical Center, Houston, TX, USA; South Central Mental Illness Research, Education, and Clinical Center, Houston, TX, USA; Big Data Scientist Training Enhancement Program (BD-STEP), VA Office of Research and Development, Washington, DC, USA
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Yuan H, Liu J, Gu Y, Ji X, Nan G. Intermittent hypoxia conditioning as a potential prevention and treatment strategy for ischemic stroke: Current evidence and future directions. Front Neurosci 2022; 16:1067411. [PMID: 36507357 PMCID: PMC9732261 DOI: 10.3389/fnins.2022.1067411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 11/11/2022] [Indexed: 11/26/2022] Open
Abstract
Ischemic stroke (IS) is the leading cause of disability and death worldwide. Owing to the aging population and unhealthy lifestyles, the incidence of cerebrovascular disease is high. Vascular risk factors include hypertension, diabetes, dyslipidemia, and obesity. Therefore, in addition to timely and effective reperfusion therapy for IS, it is crucial to actively control these risk factors to reduce the incidence and recurrence rates of IS. Evidence from human and animal studies suggests that moderate intermittent hypoxia (IH) exposure is a promising therapeutic strategy to ameliorate common vascular risk factors and comorbidities. Given the complex pathophysiological mechanisms underlying IS, effective treatment must focus on reducing injury in the acute phase and promoting repair in the recovery phase. Therefore, this review discusses the preclinical perspectives on IH conditioning as a potential treatment for neurovascular injury and highlights IH pre and postconditioning strategies for IS. Hypoxia conditioning reduces brain injury by increasing resistance to acute ischemic and hypoxic stress, exerting neuroprotective effects, and promoting post-injury repair and regeneration. However, whether IH produces beneficial effects depends not only on the hypoxic regimen but also on inter-subject differences. Therefore, we discuss the factors that may influence the effectiveness of IH treatment, including age, sex, comorbidities, and circadian rhythm, which can be used to help identify the optimal intervention population and treatment protocols for more accurate, individualized clinical translation. In conclusion, IH conditioning as a non-invasive, non-pharmacological, systemic, and multi-targeted intervention can not only reduce brain damage after stroke but can also be applied to the prevention and functional recovery of IS, providing brain protection at different stages of the disease. It represents a promising therapeutic strategy. For patients with IS and high-risk groups, IH conditioning is expected to develop as an adjunctive clinical treatment option to reduce the incidence, recurrence, disability, and mortality of IS and to reduce disease burden.
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Affiliation(s)
- Honghua Yuan
- Department of Neurology, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Jia Liu
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, China
| | - Yuhang Gu
- Department of Neurology, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Xunming Ji
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, China,Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China,*Correspondence: Xunming Ji,
| | - Guangxian Nan
- Department of Neurology, China-Japan Union Hospital of Jilin University, Changchun, China,Guangxian Nan,
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Luo B, Li Y, Zhu M, Cui J, Liu Y, Liu Y. Intermittent Hypoxia and Atherosclerosis: From Molecular Mechanisms to the Therapeutic Treatment. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:1438470. [PMID: 35965683 PMCID: PMC9365608 DOI: 10.1155/2022/1438470] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Revised: 07/12/2022] [Accepted: 07/20/2022] [Indexed: 12/24/2022]
Abstract
Intermittent hypoxia (IH) has a dual nature. On the one hand, chronic IH (CIH) is an important pathologic feature of obstructive sleep apnea (OSA) syndrome (OSAS), and many studies have confirmed that OSA-related CIH (OSA-CIH) has atherogenic effects involving complex and interacting mechanisms. Limited preventive and treatment methods are currently available for this condition. On the other hand, non-OSA-related IH has beneficial or detrimental effects on the body, depending on the degree, duration, and cyclic cycle of hypoxia. It includes two main states: intermittent hypoxia in a simulated plateau environment and intermittent hypoxia in a normobaric environment. In this paper, we compare the two types of IH and summarizes the pathologic mechanisms and research advances in the treatment of OSA-CIH-induced atherosclerosis (AS), to provide evidence for the systematic prevention and treatment of OSAS-related AS.
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Affiliation(s)
- Binyu Luo
- National Clinical Research Center for Chinese Medicine Cardiology, Xiyuan Hospital, Chinese Academy of Chinese Medical Sciences, Beijing 100091, China
| | - Yiwen Li
- National Clinical Research Center for Chinese Medicine Cardiology, Xiyuan Hospital, Chinese Academy of Chinese Medical Sciences, Beijing 100091, China
| | - Mengmeng Zhu
- National Clinical Research Center for Chinese Medicine Cardiology, Xiyuan Hospital, Chinese Academy of Chinese Medical Sciences, Beijing 100091, China
| | - Jing Cui
- National Clinical Research Center for Chinese Medicine Cardiology, Xiyuan Hospital, Chinese Academy of Chinese Medical Sciences, Beijing 100091, China
| | - Yanfei Liu
- The Second Department of Gerontology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing 100091, China
| | - Yue Liu
- National Clinical Research Center for Chinese Medicine Cardiology, Xiyuan Hospital, Chinese Academy of Chinese Medical Sciences, Beijing 100091, China
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Chen R, Zhao D, Wu Q, Chen X, Lin J, Wang D, Chen M, Lin J, Zheng Z. Mild Intermittent Hypoxia: A New Treatment Approach for Patients with Obstructive Sleep Apnea and Hypertension. Am J Respir Crit Care Med 2022; 206:122-123. [PMID: 35476716 PMCID: PMC9954325 DOI: 10.1164/rccm.202201-0134le] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Riken Chen
- The First Affiliated Hospital of Guangzhou Medical UniversityGuangzhou, Guangdong, China,State Key Laboratory of Respiratory DiseaseGuangzhou, Guangdong, China,Guangzhou Institute of Respiratory DiseaseGuangzhou, Guangdong, China,National Clinical Research Center for Respiratory DiseaseGuangzhou, Guangdong, China
| | - Dongxing Zhao
- The First Affiliated Hospital of Guangzhou Medical UniversityGuangzhou, Guangdong, China,State Key Laboratory of Respiratory DiseaseGuangzhou, Guangdong, China,Guangzhou Institute of Respiratory DiseaseGuangzhou, Guangdong, China,National Clinical Research Center for Respiratory DiseaseGuangzhou, Guangdong, China
| | - Qinglan Wu
- Central People's Hospital of ZhanjiangZhanjiang, Guangdong, China
| | - Xiaojuan Chen
- Medical College of Jiaying UniversityMeizhou, Guangdong, China
| | - Jiangpeng Lin
- The First Affiliated Hospital of Guangzhou Medical UniversityGuangzhou, Guangdong, China,State Key Laboratory of Respiratory DiseaseGuangzhou, Guangdong, China,Guangzhou Institute of Respiratory DiseaseGuangzhou, Guangdong, China,National Clinical Research Center for Respiratory DiseaseGuangzhou, Guangdong, China
| | - Donghao Wang
- The First Affiliated Hospital of Guangzhou Medical UniversityGuangzhou, Guangdong, China,State Key Laboratory of Respiratory DiseaseGuangzhou, Guangdong, China,Guangzhou Institute of Respiratory DiseaseGuangzhou, Guangdong, China,National Clinical Research Center for Respiratory DiseaseGuangzhou, Guangdong, China
| | - Mingdi Chen
- The Second Affiliated Hospital of Guangdong Medical UniversityZhanjiang, Guangdong, China
| | - Junyan Lin
- The First Affiliated Hospital of Guangzhou Medical UniversityGuangzhou, Guangdong, China,State Key Laboratory of Respiratory DiseaseGuangzhou, Guangdong, China,Guangzhou Institute of Respiratory DiseaseGuangzhou, Guangdong, China,National Clinical Research Center for Respiratory DiseaseGuangzhou, Guangdong, China
| | - Zhenzhen Zheng
- The Second Affiliated Hospital of Guangdong Medical UniversityZhanjiang, Guangdong, China,Corresponding author (e-mail: )
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González-Candia A, Candia AA, Paz A, Mobarec F, Urbina-Varela R, del Campo A, Herrera EA, Castillo RL. Cardioprotective Antioxidant and Anti-Inflammatory Mechanisms Induced by Intermittent Hypobaric Hypoxia. Antioxidants (Basel) 2022; 11:antiox11061043. [PMID: 35739940 PMCID: PMC9220055 DOI: 10.3390/antiox11061043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Revised: 05/05/2022] [Accepted: 05/06/2022] [Indexed: 11/25/2022] Open
Abstract
More than 80 million people live and work (in a chronic or intermittent form) above 2500 masl, and 35 million live in the Andean Mountains. Furthermore, in Chile, it is estimated that 100,000 people work in high-altitude shifts, where stays in the lowlands are interspersed with working visits in the highlands. Acute exposure to high altitude has been shown to induce oxidative stress in healthy human lowlanders due to increased free radical formation and decreased antioxidant capacity. However, intermittent hypoxia (IH) induces preconditioning in animal models, generating cardioprotection. Here, we aim to describe the responses of a cardiac function to four cycles of intermittent hypobaric hypoxia (IHH) in a rat model. The twelve adult Wistar rats were randomly divided into two equal groups, a four-cycle of IHH and a normobaric hypoxic control. Intermittent hypoxia was induced in a hypobaric chamber in four continuous cycles (1 cycle = 4 days of hypoxia + 4 days of normoxia), reaching a barometric pressure equivalent to 4600 m of altitude (428 Torr). At the end of the fourth cycle, cardiac structural and functional variables were also determined by echocardiography; furthermore, cardiac oxidative stress biomarkers (4-Hydroxynonenal, HNE; nitrotyrosine, NT), antioxidant enzymes, and NLRP3 inflammasome panel expression are also determined. Our results show a higher ejection and a shortening fraction of the left ventricle function by the end of the fourth cycle. Furthermore, cardiac tissue presented a decreased expression of antioxidant proteins. However, a decrease in IL-1β, TNF-αn, and oxidative stress markers is observed in IHH compared to normobaric hypoxic controls. Non-significant differences were found in protein levels of NLRP3 and caspase-1. IHH exposure determines structural and functional heart changes. These findings suggest that initial states of IHH are beneficial for cardiovascular function and protection.
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Affiliation(s)
| | - Alejandro A. Candia
- Laboratory of Vascular Function & Reactivity, Pathophysiology Program, ICBM, Faculty of Medicine, Universidad de Chile, Santiago 7500922, Chile; (A.A.C.); (A.P.); (F.M.)
- Department for the Woman and Newborn Health Promotion, Universidad de Chile, Santiago 7500922, Chile
| | - Adolfo Paz
- Laboratory of Vascular Function & Reactivity, Pathophysiology Program, ICBM, Faculty of Medicine, Universidad de Chile, Santiago 7500922, Chile; (A.A.C.); (A.P.); (F.M.)
| | - Fuad Mobarec
- Laboratory of Vascular Function & Reactivity, Pathophysiology Program, ICBM, Faculty of Medicine, Universidad de Chile, Santiago 7500922, Chile; (A.A.C.); (A.P.); (F.M.)
| | - Rodrigo Urbina-Varela
- Laboratorio de Fisiología y Bioenergética Celular, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Santiago 7820436, Chile; (R.U.-V.); (A.d.C.)
| | - Andrea del Campo
- Laboratorio de Fisiología y Bioenergética Celular, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Santiago 7820436, Chile; (R.U.-V.); (A.d.C.)
| | - Emilio A. Herrera
- Laboratory of Vascular Function & Reactivity, Pathophysiology Program, ICBM, Faculty of Medicine, Universidad de Chile, Santiago 7500922, Chile; (A.A.C.); (A.P.); (F.M.)
- International Center for Andean Studies (INCAS), University of Chile, Putre 1070000, Chile
- Correspondence: (E.A.H.); or (R.L.C.); Tel.: +56-982-337-566 (R.L.C.)
| | - Rodrigo L. Castillo
- Departamento de Medicina Interna Oriente, Facultad de Medicina, Universidad de Chile, Santiago 7500922, Chile
- Unidad de Paciente Crítico, Hospital del Salvador, Santiago 7500922, Chile
- Correspondence: (E.A.H.); or (R.L.C.); Tel.: +56-982-337-566 (R.L.C.)
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Zhang G, Zhou Y, Cao Z, Cheng X, Yue X, Zhao T, Zhao M, Zhao Y, Fan M, Zhu L. Preliminary Intermittent Hypoxia Training Alleviates the Damage of Sustained Normobaric Hypoxia on Human Hematological Indexes and Cerebral White Matter. High Alt Med Biol 2022; 23:273-283. [PMID: 35486840 DOI: 10.1089/ham.2021.0166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Zhang, Guangbo, Yanzhao Zhou, Zhengtao Cao, Xiang Cheng, Xiangpei Yue, Tong Zhao, Ming Zhao, Yongqi Zhao, Ming Fan, and Lingling Zhu. Preliminary intermittent hypoxia training alleviates the damage of sustained normobaric hypoxia on human hematological indexes and cerebral white matter. High Alt Med Biol. 00:000-000, 2022. Study Objectives: We aimed to examine the effects of preliminary intermittent hypoxia training (IHT) on human hematological indexes and cerebral white matter (WM) after exposure to a simulated altitude of 4,300 m. Methods: We recruited 20 young healthy volunteers. Participants were then randomized to either the IHT group (n = 10) or the control group (n = 10). We measured the physiological function of the control group at sea level and after exposure to a simulated altitude of 4,300 m, respectively. The IHT group performed the above tests at three time points: before and after hypoxia training, and after exposure to a simulated altitude of 4,300 m, respectively. Results: We found that mean SpO2 during day 10 of hypoxia training showed a significant increase compared with mean SpO2 on day 1 (88.3% ± 1.5% vs. 90.0% ± 1.6%, p < 0.05), and erythrocyte P50 of post-training was significantly increased compared with pretraining (37.8 ± 2.9 mmHg vs. 45.9 ± 6.4 mmHg, p < 0.05). Mean SpO2 measures after acute exposure to high altitude exhibited a significant difference, with the IHT group showing significantly greater SpO2 than the control group (73.8% ± 3.7% vs. 77.4% ± 3.2%, p < 0.05), and the Lake Louise Score was also lower than the control group (2.55 ± 2.1 vs. 6.67 ± 2.5, p < 0.05). After daily IHT, brain-derived neurotrophic factor plasma levels of participants in the IHT group did not change but significantly increased in response to high-altitude hypoxia (103.5% ± 70.4% vs. 29.7% ± 73.2%, p < 0.05). Interleukin-10 (IL-10) plasma level did not change before and after IHT in the IHT group, whereas the IL-10 plasma level of the control group after high-altitude exposure was significantly higher. Furthermore, we found that fractional anisotropy values in the left corticospinal tract and splenium of the corpus callosum in the IHT group were significantly higher than those in the control group after high-altitude hypoxia. Conclusions: These results demonstrate that IHT alleviates the damage of sustained normobaric hypoxia on human hematological indexes and cerebral WM.
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Affiliation(s)
- Guangbo Zhang
- Department of Neurobiology, Collaborative Innovation Center for Brain Disorders, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China.,Department of Brain Protection and Plasticity, Beijing Institute of Basic Medical Sciences, Beijing, China.,Department of Neurology, Kangjixintu Hospital, Renqiu, China
| | - Yanzhao Zhou
- Department of Brain Protection and Plasticity, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Zhengtao Cao
- Department of Biomedical Engineering, Air Force Medical Center, PLA, Beijing, China
| | - Xiang Cheng
- Department of Brain Protection and Plasticity, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Xiangpei Yue
- Department of Brain Protection and Plasticity, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Tong Zhao
- Department of Brain Protection and Plasticity, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Ming Zhao
- Department of Brain Protection and Plasticity, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Yongqi Zhao
- Department of Brain Protection and Plasticity, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Ming Fan
- Department of Neurobiology, Collaborative Innovation Center for Brain Disorders, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China.,Department of Brain Protection and Plasticity, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Lingling Zhu
- Department of Brain Protection and Plasticity, Beijing Institute of Basic Medical Sciences, Beijing, China
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9
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Naryzhnaya NV, Maslov LN, Derkachev IA, Ma H, Zhang Y, Prasad NR, Singh N, Fu F, Pei JM, Sarybaev A, Sydykov A. The effect of adaptation to hypoxia on cardiac tolerance to ischemia/reperfusion. J Biomed Res 2022:1-25. [PMID: 37183617 PMCID: PMC10387748 DOI: 10.7555/jbr.36.20220125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The acute myocardial infarction (AMI) and sudden cardiac death (SCD), both associated with acute cardiac ischemia, are one of the leading causes of adult death in economically developed countries. The development of new approaches for the treatment and prevention of AMI and SCD remains the highest priority for medicine. A study on the cardiovascular effects of chronic hypoxia (CH) may contribute to the development of these methods. Chronic hypoxia exerts both positive and adverse effects. The positive effects are the infarct-reducing, vasoprotective, and antiarrhythmic effects, which can lead to the improvement of cardiac contractility in reperfusion. The adverse effects are pulmonary hypertension and right ventricular hypertrophy. This review presents a comprehensive overview of how CH enhances cardiac tolerance to ischemia/reperfusion. It is an in-depth analysis of the published data on the underlying mechanisms, which can lead to future development of the cardioprotective effect of CH. A better understanding of the CH-activated protective signaling pathways may contribute to new therapeutic approaches in an increase of cardiac tolerance to ischemia/reperfusion.
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10
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Ou W, Liang Y, Qin Y, Wu W, Xie M, Zhang Y, Zhang Y, Ji L, Yu H, Li T. Hypoxic acclimation improves cardiac redox homeostasis and protects heart against ischemia-reperfusion injury through upregulation of O-GlcNAcylation. Redox Biol 2021; 43:101994. [PMID: 33964586 PMCID: PMC8121980 DOI: 10.1016/j.redox.2021.101994] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 04/11/2021] [Accepted: 04/22/2021] [Indexed: 02/05/2023] Open
Abstract
Ischemia-reperfusion (I/R) injury is detrimental to cardiovascular system. Alteration in glucose metabolism has been recognized as an important adaptive response under hypoxic conditions. However, the biological benefits underlying this metabolic phenotype remain to be elucidated. This study was designed to investigate the impact of hypoxic acclimation (HA) on cardiac I/R injury and the antioxidative mechanism(s). Male adult mice were acclimated in a hypoxic chamber (10% oxygen [O2]) for 8 h/day for 14 days, and then subjected to cardiac I/R injury by ligation of left anterior descending coronary artery for 30 min and reperfusion for 24 h or 7 days. Our results showed that HA attenuated oxidative stress and reduced infarct size in the I/R hearts. This cardioprotective effect is coupled with an elevation of protein O-linked N-acetylglucosamine (O-GlcNAc) modification partially due to inflammatory stimulation. Hyperglycosylation activated glucose-6-phosphate dehydrogenase (G6PDH), the rate-limiting enzyme in the pentose phosphate pathway, resulting in an upregulation of NADPH/NADP+ and GSH/GSSG couples and enhancement of redox homeostasis in the heart. Pharmacological suppression of O-GlcNAcylation totally abolished the influence of HA on the G6PDH activity, redox balance and post-I/R damage in the hearts and cultured cardiomyocytes, whereby augmentation of O-GlcNAcylation further enhanced the benefits, suggesting a central role of O-GlcNAcylation in HA-initiated antioxidative and cardioprotective effects. These findings, therefore, identified HA as a promising anti-I/R strategy for the heart and proposed O-GlcNAc modification of G6PDH as a therapeutic target in ischemic heart disease.
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Affiliation(s)
- Wei Ou
- Laboratory of Mitochondria and Metabolism, Department of Anesthesiology, National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, 610041, China; Laboratory of Anesthesia and Critical Care Medicine, West China Hospital of Sichuan University, Chengdu, 610041, China; Department of Anesthesiology, Nanchong Central Hospital, Nanchong, 637000, China
| | - Yu Liang
- Laboratory of Mitochondria and Metabolism, Department of Anesthesiology, National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, 610041, China; Laboratory of Anesthesia and Critical Care Medicine, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Yu Qin
- Department of Anesthesiology, The General Hospital of Western Theater Command, Chengdu, 610083, China
| | - Wei Wu
- Department of Anesthesiology, The General Hospital of Western Theater Command, Chengdu, 610083, China
| | - Maodi Xie
- Laboratory of Mitochondria and Metabolism, Department of Anesthesiology, National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, 610041, China; Laboratory of Anesthesia and Critical Care Medicine, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Yabing Zhang
- Laboratory of Mitochondria and Metabolism, Department of Anesthesiology, National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, 610041, China; Laboratory of Anesthesia and Critical Care Medicine, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Yarong Zhang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China
| | - Liwei Ji
- Laboratory of Mitochondria and Metabolism, Department of Anesthesiology, National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, 610041, China; Laboratory of Anesthesia and Critical Care Medicine, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Haiyang Yu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China
| | - Tao Li
- Laboratory of Mitochondria and Metabolism, Department of Anesthesiology, National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, 610041, China; Laboratory of Anesthesia and Critical Care Medicine, West China Hospital of Sichuan University, Chengdu, 610041, China.
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11
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Xie L, Zhen P, Yu F, Yu X, Qian H, Yang F, Tong J. Effects of sleep apnea hypopnea syndromes on cardiovascular events: a systematic review and meta-analysis. Sleep Breath 2021; 26:5-15. [PMID: 33772396 DOI: 10.1007/s11325-021-02294-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 12/13/2020] [Accepted: 01/05/2021] [Indexed: 11/30/2022]
Abstract
PURPOSE Previous studies suggest that sleep apnea hypopnea syndrome (SAHS) is an independent risk factor that contributes to certain cardiovascular events. However, there are studies arguing that patients with SAHS had lower peak troponin levels when suffering cardiovascular events compared to patients without SAHS, which indicates that there may potentially be a protective effect of SAHS. This meta-analysis aimed to assess the impact of SAHS on cardiovascular events. METHODS Databases were searched for studies that examined cardiac biomarkers or reported angiographic data when patients with SAHS experienced cardiovascular events. The data about peak cardiac biomarkers and angiographic coronary lesion were extracted and then used to compute the pooled standardized mean difference (SMD) and 95% confidence interval (95% CI). RESULTS Among 26 studies included in the meta-analysis, there was not a definite difference between the SAHS group and the control group for troponins (SMD, 0.05; 95% CI, [- 0.16, 0.26]), creatine kinase (SMD, - 0.08; 95% CI, [- 0.38, 0.22]), and CK-MB (SMD, - 0.11; 95% CI, [- 0.51, 0.29]). However, patients with SAHS revealed worse coronary lesion condition grading via both Gensini score (SMD, 0.63; 95% CI, [0.31, 0.95]) and SYNTAX score (SMD, 0.99; 95% CI, [0.31-1.67]). CONCLUSIONS Ischemic preconditioning induced by the intermittent hypoxia at the early stage could generate a cardiac protection effect, which would then benefit SAHS patients encountering a major adverse cardiovascular event.
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Affiliation(s)
- Liang Xie
- School of Medicine, Southeast University, Nanjing, China.,Jinling Hospitial, School of Medicine, Nanjing University, Nanjing, China
| | - Penghao Zhen
- School of Medicine, Southeast University, Nanjing, China.,Department of Cardiology, Zhongda Hospital, Nanjing, China
| | - Fuchao Yu
- School of Medicine, Southeast University, Nanjing, China.,Department of Cardiology, Zhongda Hospital, Nanjing, China
| | - Xiaojin Yu
- School of Public Health, Southeast University, 87 Dingjiaqiao, Nanjing, China
| | - Hai Qian
- Center of Drug Discovery, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Fang Yang
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biomedical Sciences and Medical Engineering, Southeast University, Nanjing, China
| | - Jiayi Tong
- School of Medicine, Southeast University, Nanjing, China. .,Department of Cardiology, Zhongda Hospital, Nanjing, China.
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12
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[Into thin air - Altitude training and hypoxic conditioning: From athlete to patient]. Rev Mal Respir 2021; 38:404-417. [PMID: 33722445 DOI: 10.1016/j.rmr.2021.02.066] [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: 07/12/2019] [Accepted: 10/15/2020] [Indexed: 11/20/2022]
Abstract
INTRODUCTION Hypoxic exposure should be considered as a continuum, the effects of which depend on the dose and individual response to hypoxia. Hypoxic conditioning (HC) represents an innovative and promising strategy, ranging from improved human performance to therapeutic applications. STATE OF THE ART With the aim of improving sports performance, the effectiveness of hypoxic exposure, whether natural or simulated, is difficult to demonstrate because of the large variability of the protocols used. In therapeutics, the benefits of HC are described in many pathological conditions such as obesity or cardiovascular pathologies. If the HC benefits from a strong preclinical rationale, its application to humans remains limited. PERSPECTIVES Advances in training and acclimation will require greater personalization and precise periodization of hypoxic exposures. For patients, the harmonization of HC protocols, the identification of biomarkers and the development and subsequent validation of devices allowing a precise control of the hypoxic stimulus are necessary steps for the development of HC. CONCLUSIONS From the athlete to the patient, HC represents an innovative and promising field of research, ranging from the improvement of human performance to the prevention and treatment of certain pathologies.
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13
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Jarrard CP, Nagel MJ, Stray-Gundersen S, Tanaka H, Lalande S. Hypoxic preconditioning attenuates ischemia-reperfusion injury in young healthy adults. J Appl Physiol (1985) 2021; 130:846-852. [DOI: 10.1152/japplphysiol.00772.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ischemia-reperfusion injury induced by restoration of blood flow following occlusion impairs flow-mediated dilation, a marker of endothelium-dependent vasodilation. In young healthy adults, exposure to intermittent hypoxia, consisting of alternating short bouts of breathing hypoxic and normoxic air, before an ischemia-reperfusion injury significantly attenuated the reduction in flow-mediated dilation. Thus, hypoxic preconditioning represents a potential strategy to mitigate the effect of ischemia-reperfusion injury associated with ischemic events.
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Affiliation(s)
- Caitlin P. Jarrard
- Department of Kinesiology and Health Education, The University of Texas at Austin, Austin, Texas
| | - Mercedes J. Nagel
- Department of Kinesiology and Health Education, The University of Texas at Austin, Austin, Texas
| | - Sten Stray-Gundersen
- Department of Kinesiology and Health Education, The University of Texas at Austin, Austin, Texas
| | - Hirofumi Tanaka
- Department of Kinesiology and Health Education, The University of Texas at Austin, Austin, Texas
| | - Sophie Lalande
- Department of Kinesiology and Health Education, The University of Texas at Austin, Austin, Texas
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14
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Hu K, Deng W, Yang J, Wei Y, Wen C, Li X, Chen Q, Ke D, Li G. Intermittent hypoxia reduces infarct size in rats with acute myocardial infarction: a systematic review and meta-analysis. BMC Cardiovasc Disord 2020; 20:422. [PMID: 32962654 PMCID: PMC7507284 DOI: 10.1186/s12872-020-01702-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 09/09/2020] [Indexed: 11/20/2022] Open
Abstract
Background To determine whether intermittent hypoxia (IH) can reduce the infarct size (IS) after acute myocardial infarction (AMI) in rats. Methods Articles were identified in PubMed, EMBASE and the Web of Science and were included if they evaluated the effect of IH on the changes in the infarcted area after AMI in rats. Results A preliminary search identified 3633 articles and 29 data sets from 23 articles (12 in vivo, 16 in vitro). The IS decreased after AMI in IH rats both in vitro (SMD -1.46, 95% CI [− 2.37, − 0.55]; I2 = 85.6%, P = 0.000) and in vivo (SMD -1.43, 95% CI [− 2.05, − 0.82], I2 = 73.6%, P = 0.000). Sensitivity analysis indicated that IH had a strong protective effect against myocardial infarction, and the hypoxia concentration was significantly correlated with the change in IS after AMI. Conclusion IH can reduce IS after AMI in rats. This effect of IH may be related to the dose of hypoxia, and the oxygen concentration may be one of the most important influencing factors.
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Affiliation(s)
- Ke Hu
- Department of Nephrology, The Second Affiliated Hospital of Chongqing Medical University, No. 74, Linjiang Road, Yuzhong District, Chongqing, 400010, China
| | - Wei Deng
- Department of Geriatrics, The Second Affiliated Hospital of Chongqing Medical University, No. 74, Linjiang Road, Yuzhong District, Chongqing, 400010, China.
| | - Jing Yang
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, No. 74, Linjiang Road, Yuzhong District, Chongqing, 400010, China
| | - Yu Wei
- Department of Geriatrics, The Second Affiliated Hospital of Chongqing Medical University, No. 74, Linjiang Road, Yuzhong District, Chongqing, 400010, China
| | - Chaolin Wen
- Department of Geriatrics, The Second Affiliated Hospital of Chongqing Medical University, No. 74, Linjiang Road, Yuzhong District, Chongqing, 400010, China
| | - Xingsheng Li
- Department of Geriatrics, The Second Affiliated Hospital of Chongqing Medical University, No. 74, Linjiang Road, Yuzhong District, Chongqing, 400010, China
| | - Qingwei Chen
- Department of Geriatrics, The Second Affiliated Hospital of Chongqing Medical University, No. 74, Linjiang Road, Yuzhong District, Chongqing, 400010, China
| | - Dazhi Ke
- Department of Geriatrics, The Second Affiliated Hospital of Chongqing Medical University, No. 74, Linjiang Road, Yuzhong District, Chongqing, 400010, China
| | - Guiqiong Li
- Department of Geriatrics, The Second Affiliated Hospital of Chongqing Medical University, No. 74, Linjiang Road, Yuzhong District, Chongqing, 400010, China
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15
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Ryan S, Cummins EP, Farre R, Gileles-Hillel A, Jun JC, Oster H, Pepin JL, Ray DW, Reutrakul S, Sanchez-de-la-Torre M, Tamisier R, Almendros I. Understanding the pathophysiological mechanisms of cardiometabolic complications in obstructive sleep apnoea: towards personalised treatment approaches. Eur Respir J 2020; 56:13993003.02295-2019. [PMID: 32265303 DOI: 10.1183/13993003.02295-2019] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 03/15/2020] [Indexed: 12/19/2022]
Abstract
In January 2019, a European Respiratory Society research seminar entitled "Targeting the detrimental effects of sleep disturbances and disorders" was held in Dublin, Ireland. It provided the opportunity to critically review the current evidence of pathophysiological responses of sleep disturbances, such as sleep deprivation, sleep fragmentation or circadian misalignment and of abnormalities in physiological gases such as oxygen and carbon dioxide, which occur frequently in respiratory conditions during sleep. A specific emphasis of the seminar was placed on the evaluation of the current state of knowledge of the pathophysiology of cardiovascular and metabolic diseases in obstructive sleep apnoea (OSA). Identification of the detailed mechanisms of these processes is of major importance to the field and this seminar offered an ideal platform to exchange knowledge, and to discuss pitfalls of current models and the design of future collaborative studies. In addition, we debated the limitations of current treatment strategies for cardiometabolic complications in OSA and discussed potentially valuable alternative approaches.
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Affiliation(s)
- Silke Ryan
- Pulmonary and Sleep Disorders Unit, St Vincent's University Hospital, Dublin, Ireland .,School of Medicine, Conway Institute, University College Dublin, Dublin, Ireland
| | - Eoin P Cummins
- School of Medicine, Conway Institute, University College Dublin, Dublin, Ireland
| | - Ramon Farre
- Unitat de Biofísica i Bioenginyeria, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona-IDIBAPS, and CIBER Enfermedades Respiratorias, Barcelona, Spain
| | - Alex Gileles-Hillel
- Pediatric Pulmonology and Sleep Unit, Dept of Pediatrics, and The Wohl Institute for Translational Medicine, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Jonathan C Jun
- Pulmonary and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Henrik Oster
- Institute of Neurobiology, University of Lübeck, Lübeck, Germany
| | | | - David W Ray
- NIHR Oxford Biomedical Research Centre, John Radcliffe Hospital, Oxford, UK.,Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, UK
| | - Sirimon Reutrakul
- Division of Endocrinology, Diabetes, and Metabolism, Dept of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Manuel Sanchez-de-la-Torre
- Group of Precision Medicine in Chronic Diseases, Hospital Arnau de Vilanova-Santa Maria, IRBLleida, Lleida, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Renaud Tamisier
- HP2 INSERM U1042, Université Grenoble Alpes, Grenoble, France
| | - Isaac Almendros
- Unitat de Biofísica i Bioenginyeria, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona-IDIBAPS, and CIBER Enfermedades Respiratorias, Barcelona, Spain
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16
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Wang H, Shi X, Schenck H, Hall JR, Ross SE, Kline GP, Chen S, Mallet RT, Chen P. Intermittent Hypoxia Training for Treating Mild Cognitive Impairment: A Pilot Study. Am J Alzheimers Dis Other Demen 2020; 35:1533317519896725. [PMID: 31902230 PMCID: PMC10624018 DOI: 10.1177/1533317519896725] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Although intermittent hypoxia training (IHT) has proven effective against various clinical disorders, its impact on mild cognitive impairment (MCI) is unknown. This pilot study examined IHT's safety and therapeutic efficacy in elderly patients with amnestic MCI (aMCI). Seven patients with aMCI (age 69 ± 3 years) alternately breathed 10% O2 and room-air, each 5 minutes, for 8 cycles/session, 3 sessions/wk for 8 weeks. The patients' resting arterial pressures fell by 5 to 7 mm Hg (P < .05) and cerebral tissue oxygenation increased (P < .05) following IHT. Intermittent hypoxia training enhanced hypoxemia-induced cerebral vasodilation (P < .05) and improved mini-mental state examination and digit span scores from 25.7 ± 0.4 to 27.7 ± 0.6 (P = .038) and from 24.7 ± 1.2 to 26.1 ± 1.3 (P = .047), respectively. California verbal learning test score tended to increase (P = .102), but trail making test-B and controlled oral word association test scores were unchanged. Adaptation to moderate IHT may enhance cerebral oxygenation and hypoxia-induced cerebrovasodilation while improving short-term memory and attention in elderly patients with aMCI.
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Affiliation(s)
- Hong Wang
- Departments of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, USA
- Shanghai University of Medicine & Health Sciences, Shanghai, China
| | - Xiangrong Shi
- Departments of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, USA
- Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Hannah Schenck
- Departments of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - James R. Hall
- Departments of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, USA
- Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Sarah E. Ross
- Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, TX, USA
- Department of Internal Medicine, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Geoffrey P. Kline
- Department of Internal Medicine, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Shande Chen
- Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Robert T. Mallet
- Departments of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Peijie Chen
- Shanghai University of Sport, Shanghai, China
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17
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Serebrovska ZO, Serebrovska TV, Kholin VA, Tumanovska LV, Shysh AM, Pashevin DA, Goncharov SV, Stroy D, Grib ON, Shatylo VB, Bachinskaya NY, Egorov E, Xi L, Dosenko VE. Intermittent Hypoxia-Hyperoxia Training Improves Cognitive Function and Decreases Circulating Biomarkers of Alzheimer's Disease in Patients with Mild Cognitive Impairment: A Pilot Study. Int J Mol Sci 2019; 20:E5405. [PMID: 31671598 PMCID: PMC6862463 DOI: 10.3390/ijms20215405] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 10/23/2019] [Accepted: 10/24/2019] [Indexed: 12/15/2022] Open
Abstract
Alzheimer's disease (AD) affects not only the central nervous system, but also peripheral blood cells including neutrophils and platelets, which actively participate in pathogenesis of AD through a vicious cycle between platelets aggregation and production of excessive amyloid beta (Aβ). Platelets adhesion on amyloid plaques also increases the risk of cerebral microcirculation disorders. Moreover, activated platelets release soluble adhesion molecules that cause migration, adhesion/activation of neutrophils and formation of neutrophil extracellular traps (NETs), which may damage blood brain barrier and destroy brain parenchyma. The present study examined the effects of intermittent hypoxic-hyperoxic training (IHHT) on elderly patients with mild cognitive impairment (MCI), a precursor of AD. Twenty-one participants (age 51-74 years) were divided into three groups: Healthy Control (n = 7), MCI+Sham (n = 6), and MCI+IHHT (n = 8). IHHT was carried out five times per week for three weeks (total 15 sessions). Each IHHT session consisted of four cycles of 5-min hypoxia (12% FIO2) and 3-min hyperoxia (33% FIO2). Cognitive parameters, Aβ and amyloid precursor protein (APP) expression, microRNA 29, and long non-coding RNA in isolated platelets as well as NETs in peripheral blood were investigated. We found an initial decline in cognitive function indices in both MCI+Sham and MCI+IHHT groups and significant correlations between cognitive test scores and the levels of circulating biomarkers of AD. Whereas sham training led to no change in these parameters, IHHT resulted in the improvement in cognitive test scores, along with significant increase in APP ratio and decrease in Aβ expression and NETs formation one day after the end of three-week IHHT. Such effects on Aβ expression and NETs formation remained more pronounced one month after IHHT. In conclusion, our results from this pilot study suggested a potential utility of IHHT as a new non-pharmacological therapy to improve cognitive function in pre-AD patients and slow down the development of AD.
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Affiliation(s)
- Zoya O Serebrovska
- Department of General and Molecular Pathophysiology, Bogomoletz Institute of Physiology, Kyiv 01024, Ukraine.
| | | | - Viktor A Kholin
- Department of Age Physiology and Pathology of Nervous System, Chebotarev Institute of Gerontology NAMS of Ukraine, Kyiv 04114, Ukraine.
| | - Lesya V Tumanovska
- Department of General and Molecular Pathophysiology, Bogomoletz Institute of Physiology, Kyiv 01024, Ukraine.
| | - Angela M Shysh
- Department of General and Molecular Pathophysiology, Bogomoletz Institute of Physiology, Kyiv 01024, Ukraine.
| | - Denis A Pashevin
- Department of General and Molecular Pathophysiology, Bogomoletz Institute of Physiology, Kyiv 01024, Ukraine.
| | - Sergii V Goncharov
- Department of General and Molecular Pathophysiology, Bogomoletz Institute of Physiology, Kyiv 01024, Ukraine.
| | - Dmytro Stroy
- Department of General and Molecular Pathophysiology, Bogomoletz Institute of Physiology, Kyiv 01024, Ukraine.
| | - Oksana N Grib
- Department of Clinical Physiology and Pathology of Internal Organs, Chebotarev Institute of Gerontology NAMS of Ukraine, Kyiv 04114, Ukraine.
| | - Valeriy B Shatylo
- Department of Clinical Physiology and Pathology of Internal Organs, Chebotarev Institute of Gerontology NAMS of Ukraine, Kyiv 04114, Ukraine.
| | - Natalia Yu Bachinskaya
- Department of Age Physiology and Pathology of Nervous System, Chebotarev Institute of Gerontology NAMS of Ukraine, Kyiv 04114, Ukraine.
| | - Egor Egorov
- CellAir Constructions GmbH, Schorndorf 73614, Germany.
| | - Lei Xi
- Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA 23298-0204, USA.
| | - Victor E Dosenko
- Department of General and Molecular Pathophysiology, Bogomoletz Institute of Physiology, Kyiv 01024, Ukraine.
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18
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Jung ME, Mallet RT. Intermittent hypoxia training: Powerful, non-invasive cerebroprotection against ethanol withdrawal excitotoxicity. Respir Physiol Neurobiol 2018; 256:67-78. [PMID: 28811138 PMCID: PMC5825251 DOI: 10.1016/j.resp.2017.08.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Revised: 07/24/2017] [Accepted: 08/08/2017] [Indexed: 12/12/2022]
Abstract
Ethanol intoxication and withdrawal exact a devastating toll on the central nervous system. Abrupt ethanol withdrawal provokes massive release of the excitatory neurotransmitter glutamate, which over-activates its postsynaptic receptors, causing intense Ca2+ loading, p38 mitogen activated protein kinase activation and oxidative stress, culminating in ATP depletion, mitochondrial injury, amyloid β deposition and neuronal death. Collectively, these mechanisms produce neurocognitive and sensorimotor dysfunction that discourages continued abstinence. Although the brain is heavily dependent on blood-borne O2 to sustain its aerobic ATP production, brief, cyclic episodes of moderate hypoxia and reoxygenation, when judiciously applied over the course of days or weeks, evoke adaptations that protect the brain from ethanol withdrawal-induced glutamate excitotoxicity, mitochondrial damage, oxidative stress and amyloid β accumulation. This review summarizes evidence from ongoing preclinical research that demonstrates intermittent hypoxia training to be a potentially powerful yet non-invasive intervention capable of affording robust, sustained neuroprotection during ethanol withdrawal.
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Affiliation(s)
- Marianna E Jung
- Center for Neuroscience Discovery, University of North Texas Health Science Center, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107-2699, USA.
| | - Robert T Mallet
- Institute for Cardiovascular and Metabolic Diseases, University of North Texas Health Science Center, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107-2699, USA.
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Mallet RT, Manukhina EB, Ruelas SS, Caffrey JL, Downey HF. Cardioprotection by intermittent hypoxia conditioning: evidence, mechanisms, and therapeutic potential. Am J Physiol Heart Circ Physiol 2018; 315:H216-H232. [PMID: 29652543 DOI: 10.1152/ajpheart.00060.2018] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The calibrated application of limited-duration, cyclic, moderately intense hypoxia-reoxygenation increases cardiac resistance to ischemia-reperfusion stress. These intermittent hypoxic conditioning (IHC) programs consistently produce striking reductions in myocardial infarction and ventricular tachyarrhythmias after coronary artery occlusion and reperfusion and, in many cases, improve contractile function and coronary blood flow. These IHC protocols are fundamentally different from those used to simulate sleep apnea, a recognized cardiovascular risk factor. In clinical studies, IHC improved exercise capacity and decreased arrhythmias in patients with coronary artery or pulmonary disease and produced robust, persistent, antihypertensive effects in patients with essential hypertension. The protection afforded by IHC develops gradually and depends on β-adrenergic, δ-opioidergic, and reactive oxygen-nitrogen signaling pathways that use protein kinases and adaptive transcription factors. In summary, adaptation to intermittent hypoxia offers a practical, largely unrecognized means of protecting myocardium from impending ischemia. The myocardial and perhaps broader systemic protection provided by IHC clearly merits further evaluation as a discrete intervention and as a potential complement to conventional pharmaceutical and surgical interventions.
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Affiliation(s)
- Robert T Mallet
- Department of Integrative Physiology and Anatomy, University of North Texas Health Science Center , Fort Worth, Texas
| | - Eugenia B Manukhina
- Department of Integrative Physiology and Anatomy, University of North Texas Health Science Center , Fort Worth, Texas.,Institute of General Pathology and Pathophysiology, Russian Academy of Medical Sciences , Moscow , Russian Federation.,School of Medical Biology South Ural State University , Chelyabinsk , Russian Federation
| | - Steven Shea Ruelas
- Department of Integrative Physiology and Anatomy, University of North Texas Health Science Center , Fort Worth, Texas
| | - James L Caffrey
- Department of Integrative Physiology and Anatomy, University of North Texas Health Science Center , Fort Worth, Texas
| | - H Fred Downey
- Department of Integrative Physiology and Anatomy, University of North Texas Health Science Center , Fort Worth, Texas.,School of Medical Biology South Ural State University , Chelyabinsk , Russian Federation
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Intermittent hypoxia-generated ROS contributes to intracellular zinc regulation that limits ischemia/reperfusion injury in adult rat cardiomyocyte. J Mol Cell Cardiol 2018; 118:122-132. [PMID: 29577873 DOI: 10.1016/j.yjmcc.2018.03.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 03/05/2018] [Accepted: 03/21/2018] [Indexed: 12/20/2022]
Abstract
Intermittent hypoxia (IH) has been shown to exert cardioprotective effects against ischemia/reperfusion (I/R) injury through the preservation of ion homeostasis. I/R dramatically elevated cytosolic Zn2+ and caused cardiomyocyte death. However, the role of IH exposure in the relationship between Zn2+ regulation and cardioprotection is still unclear. The aim of the present study was to study whether IH exposure could help in intracellular Zn2+ regulation, hence contributing to cardioprotection against I/R injury. Adult rat cardiomyocytes were exposed to IH (5% O2, 5% CO2 and balanced N2) for 30 min followed by 30 min of normoxia (21% O2, 5% CO2 and balanced N2). Changes in intracellular Zn2+ concentration were determined using a Zn2+-specific fluorescent dye, FluoZin-3 or RhodZin-3. Fluorescence was monitored under an inverted fluorescent or confocal microscope. The results demonstrated that I/R or 2,2'-dithiodipyridine (DTDP), a reactive disulphide compound, induced Zn2+ release from metallothioneins (MTs), subsequently causing cytosolic Zn2+ overload, which in turn increased intracellular Zn2+ entry into the mitochondria via a Ca2+ uniporter, hence inducing mitochondrial membrane potential loss, and eventually led to cell death. However, the cytosolic Zn2+ overload and cell death caused by I/R or DTDP was significantly reduced by treatment of cardiomyocytes with IH. The findings from this study suggest that IH might exert its cardioprotective effect through reducing the I/R-induced cytosolic Zn2+ overload and cell death in cardiomyocytes.
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21
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Aguilar M, González-Candia A, Rodríguez J, Carrasco-Pozo C, Cañas D, García-Herrera C, Herrera EA, Castillo RL. Mechanisms of Cardiovascular Protection Associated with Intermittent Hypobaric Hypoxia Exposure in a Rat Model: Role of Oxidative Stress. Int J Mol Sci 2018; 19:ijms19020366. [PMID: 29373484 PMCID: PMC5855588 DOI: 10.3390/ijms19020366] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 01/08/2018] [Accepted: 01/09/2018] [Indexed: 12/25/2022] Open
Abstract
More than 140 million people live and works (in a chronic or intermittent form) above 2500 m worldwide and 35 million live in the Andean Mountains. Furthermore, in Chile, it is estimated that 55,000 persons work in high altitude shifts, where stays at lowlands and interspersed with working stays at highlands. Acute exposure to high altitude has been shown to induce oxidative stress in healthy human lowlanders, due to an increase in free radical formation and a decrease in antioxidant capacity. However, in animal models, intermittent hypoxia (IH) induce preconditioning, like responses and cardioprotection. Here, we aimed to describe in a rat model the responses on cardiac and vascular function to 4 cycles of intermittent hypobaric hypoxia (IHH). Twelve adult Wistar rats were randomly divided into two equal groups, a four-cycle of IHH, and a normobaric hypoxic control. Intermittent hypoxia was induced in a hypobaric chamber in four continuous cycles (1 cycle = 4 days hypoxia + 4 days normoxia), reaching a barometric pressure equivalent to 4600 m of altitude (428 Torr). At the end of the first and fourth cycle, cardiac structural, and functional variables were determined by echocardiography. Thereafter, ex vivo vascular function and biomechanical properties were determined in femoral arteries by wire myography. We further measured cardiac oxidative stress biomarkers (4-Hydroxy-nonenal, HNE; nytrotirosine, NT), reactive oxygen species (ROS) sources (NADPH and mitochondrial), and antioxidant enzymes activity (catalase, CAT; glutathione peroxidase, GPx, and superoxide dismutase, SOD). Our results show a higher ejection and shortening fraction of the left ventricle function by the end of the 4th cycle. Further, femoral vessels showed an improvement of vasodilator capacity and diminished stiffening. Cardiac tissue presented a higher expression of antioxidant enzymes and mitochondrial ROS formation in IHH, as compared with normobaric hypoxic controls. IHH exposure determines a preconditioning effect on the heart and femoral artery, both at structural and functional levels, associated with the induction of antioxidant defence mechanisms. However, mitochondrial ROS generation was increased in cardiac tissue. These findings suggest that initial states of IHH are beneficial for cardiovascular function and protection.
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Affiliation(s)
- Miguel Aguilar
- Programa de Fisiopatología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago 7500922, Chile.
| | - Alejandro González-Candia
- Programa de Fisiopatología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago 7500922, Chile.
| | - Jorge Rodríguez
- Programa de Fisiopatología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago 7500922, Chile.
- Departamento de Kinesiología, Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile.
| | - Catalina Carrasco-Pozo
- Discovery Biology, Griffith Institute for Drug Discovery, Griffith University, Brisbane, QLD 4222, Australia.
- Departamento de Nutrición, Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile.
| | - Daniel Cañas
- Departamento de Ingeniería Mecánica, Facultad de Ingeniería, Universidad de Santiago de Chile, Santiago 9170125, Chile.
| | - Claudio García-Herrera
- Departamento de Ingeniería Mecánica, Facultad de Ingeniería, Universidad de Santiago de Chile, Santiago 9170125, Chile.
| | - Emilio A Herrera
- Programa de Fisiopatología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago 7500922, Chile.
- International Center for Andean Studies, Universidad de Chile, Putre, Chile.
| | - Rodrigo L Castillo
- Programa de Fisiopatología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago 7500922, Chile.
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Kiss A, Tratsiakovich Y, Mahdi A, Yang J, Gonon AT, Podesser BK, Pernow J. Vagal nerve stimulation reduces infarct size via a mechanism involving the alpha-7 nicotinic acetylcholine receptor and downregulation of cardiac and vascular arginase. Acta Physiol (Oxf) 2017; 221:174-181. [PMID: 28238218 DOI: 10.1111/apha.12861] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 12/17/2016] [Accepted: 02/21/2017] [Indexed: 02/05/2023]
Abstract
AIMS Vagal nerve stimulation (VNS) protects from myocardial and vascular injury following myocardial ischaemia and reperfusion (IR) via a mechanism involving activation of alpha-7 nicotinic acetylcholine receptor (α7 nAChR) and reduced inflammation. Arginase is involved in development of myocardial IR injury driven by inflammatory mediators. The aim of the study was to clarify whether VNS downregulates myocardial and vascular arginase via a mechanism involving activation of α7 nAChR following myocardial IR. METHODS Anaesthetized rats were randomized to (i) sham-operated, (ii) control IR (30-min ischaemia and 2-h reperfusion, (iii) VNS throughout IR, (iv) the arginase inhibitor nor-NOHA+IR, (v) nor-NOHA+VNS+IR, (vi) selective α7 nAChR blockade by methyllycaconitine (MLA) followed by VNS throughout IR and (vii) MLA+IR. RESULTS Infarct size was reduced by VNS compared to control IR (41 ± 3% vs. 67 ± 2% of the myocardium at risk, P < 0.001). Myocardial IR increased myocardial and aortic arginase activity 1.7- and 3.1-fold respectively (P < 0.05). VNS attenuated the increase in arginase activity compared to control IR both in the myocardium and aorta (P < 0.05). MLA partially abolished the cardioprotective effect of VNS and completely abrogated the effect of VNS on arginase activity. Arginase inhibition combined with VNS did not further reduce infarct size. CONCLUSION Vagal nerve stimulation reduced infarct size and reversed the upregulation of arginase induced by IR both in the myocardium and aorta via a mechanism depending on α7 nAChR activation. The data suggest that the cardioprotective effect of VNS is mediated via reduction in arginase activity.
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Affiliation(s)
- A. Kiss
- Department of Medicine; Unit of Cardiology; Karolinska Institutet; Heart and Vascular Theme; Karolinska University Hospital; Stockholm Sweden
- Ludwig Boltzmann Cluster for Cardiovascular Research at the Center for Biomedical Research; Medical University of Vienna; Vienna Austria
| | - Y. Tratsiakovich
- Department of Medicine; Unit of Cardiology; Karolinska Institutet; Heart and Vascular Theme; Karolinska University Hospital; Stockholm Sweden
| | - A. Mahdi
- Department of Medicine; Unit of Cardiology; Karolinska Institutet; Heart and Vascular Theme; Karolinska University Hospital; Stockholm Sweden
| | - J. Yang
- Department of Medicine; Unit of Cardiology; Karolinska Institutet; Heart and Vascular Theme; Karolinska University Hospital; Stockholm Sweden
| | - A. T. Gonon
- Department of Medicine; Unit of Cardiology; Karolinska Institutet; Heart and Vascular Theme; Karolinska University Hospital; Stockholm Sweden
| | - B. K. Podesser
- Ludwig Boltzmann Cluster for Cardiovascular Research at the Center for Biomedical Research; Medical University of Vienna; Vienna Austria
| | - J. Pernow
- Department of Medicine; Unit of Cardiology; Karolinska Institutet; Heart and Vascular Theme; Karolinska University Hospital; Stockholm Sweden
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δ-Opioid receptors: Pivotal role in intermittent hypoxia-augmentation of cardiac parasympathetic control and plasticity. Auton Neurosci 2016; 198:38-49. [PMID: 27498137 DOI: 10.1016/j.autneu.2016.07.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 07/12/2016] [Accepted: 07/22/2016] [Indexed: 01/08/2023]
Abstract
BACKGROUND Intermittent hypoxia training (IHT) produces robust myocardial protection against ischemia-reperfusion induced infarction and arrhythmias. Blockade of this cardioprotection by antagonism of either β1-adrenergic or δ-opioid receptors (δ-OR) suggests autonomic and/or opioidergic adaptations. PURPOSE To test the hypothesis that IHT shifts cardiac autonomic balance toward greater cholinergic and opioidergic influence. METHODS Mongrel dogs completed 20d IHT, non-hypoxic sham training, or IHT with the δ-OR antagonist naltrindole (200μg/kgsc). The vagolytic effect of the δ-OR agonist met-enkephalin-arg-phe delivered by sinoatrial microdialysis was evaluated following IHT. Sinoatrial, atrial and left ventricular biopsies were analyzed for changes in δ-OR, the neurotrophic monosialoganglioside, GM-1, and cholinergic and adrenergic markers. RESULTS IHT enhanced vagal bradycardia vs. sham dogs (P<0.05), and blunted the δ2-OR mediated vagolytic effect of met-enkephalin-arg-phe. The GM-1 labeled fibers overlapped strongly with cholinergic markers, and IHT increased the intensity of both signals (P<0.05). IHT increased low and high intensity vesicular acetylcholine transporter labeling of sinoatrial nodal fibers (P<0.05) suggesting an increase in parasympathetic arborization. IHT reduced select δ-OR labeled fibers in both the atria and sinoatrial node (P<0.05) consistent with moderation of the vagolytic δ2-OR signaling described above. Furthermore, blockade of δ-OR signaling with naltrindole during IHT increased the protein content of δ-OR (atria and ventricle) and vesicular acetylcholine transporter (atria) vs. sham and untreated IHT groups. IHT also reduced the sympathetic marker, tyrosine hydroxylase in ventricle (P<0.05). SUMMARY IHT shifts cardiac autonomic balance in favor of parasympathetic control via adaptations in opioidergic, ganglioside, and adrenergic systems.
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Manukhina EB, Downey HF, Shi X, Mallet RT. Intermittent hypoxia training protects cerebrovascular function in Alzheimer's disease. Exp Biol Med (Maywood) 2016; 241:1351-63. [PMID: 27190276 DOI: 10.1177/1535370216649060] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Alzheimer's disease (AD) is a leading cause of death and disability among older adults. Modifiable vascular risk factors for AD (VRF) include obesity, hypertension, type 2 diabetes mellitus, sleep apnea, and metabolic syndrome. Here, interactions between cerebrovascular function and development of AD are reviewed, as are interventions to improve cerebral blood flow and reduce VRF. Atherosclerosis and small vessel cerebral disease impair metabolic regulation of cerebral blood flow and, along with microvascular rarefaction and altered trans-capillary exchange, create conditions favoring AD development. Although currently there are no definitive therapies for treatment or prevention of AD, reduction of VRFs lowers the risk for cognitive decline. There is increasing evidence that brief repeated exposures to moderate hypoxia, i.e. intermittent hypoxic training (IHT), improve cerebral vascular function and reduce VRFs including systemic hypertension, cardiac arrhythmias, and mental stress. In experimental AD, IHT nearly prevented endothelial dysfunction of both cerebral and extra-cerebral blood vessels, rarefaction of the brain vascular network, and the loss of neurons in the brain cortex. Associated with these vasoprotective effects, IHT improved memory and lessened AD pathology. IHT increases endothelial production of nitric oxide (NO), thereby increasing regional cerebral blood flow and augmenting the vaso- and neuroprotective effects of endothelial NO. On the other hand, in AD excessive production of NO in microglia, astrocytes, and cortical neurons generates neurotoxic peroxynitrite. IHT enhances storage of excessive NO in the form of S-nitrosothiols and dinitrosyl iron complexes. Oxidative stress plays a pivotal role in the pathogenesis of AD, and IHT reduces oxidative stress in a number of experimental pathologies. Beneficial effects of IHT in experimental neuropathologies other than AD, including dyscirculatory encephalopathy, ischemic stroke injury, audiogenic epilepsy, spinal cord injury, and alcohol withdrawal stress have also been reported. Further research on the potential benefits of IHT in AD and other brain pathologies is warranted.
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Affiliation(s)
- Eugenia B Manukhina
- University of North Texas Health Science Center, Fort Worth, TX 76107-2699, USA Institute of General Pathology and Pathophysiology, Moscow 125315, Russian Federation
| | - H Fred Downey
- University of North Texas Health Science Center, Fort Worth, TX 76107-2699, USA
| | - Xiangrong Shi
- University of North Texas Health Science Center, Fort Worth, TX 76107-2699, USA
| | - Robert T Mallet
- University of North Texas Health Science Center, Fort Worth, TX 76107-2699, USA
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Mateika JH, Komnenov D. Intermittent hypoxia initiated plasticity in humans: A multipronged therapeutic approach to treat sleep apnea and overlapping co-morbidities. Exp Neurol 2016; 287:113-129. [PMID: 27170208 DOI: 10.1016/j.expneurol.2016.05.011] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 03/18/2016] [Accepted: 05/03/2016] [Indexed: 10/21/2022]
Abstract
Over the past three decades exposure to intermittent hypoxia (IH) has generally been considered a stimulus associated with a number of detrimental outcomes. However, there is sufficient evidence to link IH to many beneficial outcomes but they have largely been ignored, particularly in the field of sleep medicine in the United States. Recent reviews have postulated that this apparent contradiction is related to the severity and duration of exposure to IH; mild forms of IH initiate beneficial outcomes while severe forms of IH are coupled to detrimental consequences. In the present review we explore the role that IH has in initiating respiratory plasticity and the potential this form of plasticity has to mitigate obstructive sleep apnea (OSA) in humans. In taking this approach, we address the possibility that IH could serve as an adjunct therapy coupled with continuous positive airway pressure (CPAP) to treat OSA. Our working hypothesis is that exposure to mild IH leads to respiratory plasticity that manifests in increased stability of the upper airway, which could ultimately reduce the CPAP required to treat OSA. In turn, this reduction could increase CPAP compliance and extend the length of treatment each night, which might improve the magnitude of outcome measures. Improved treatment compliance coupled with the direct effect that IH has on numerous overlapping conditions (i.e. asthma, chronic obstructive pulmonary disease, spinal cord injury) may well lead to substantial improvements that exceed outcomes following treatment with CPAP alone. Overall, this review will consider evidence from the published literature which suggests that IH could serve as an effective multipronged therapeutic approach to treat sleep apnea and its overlapping co-morbidities.
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Affiliation(s)
- Jason H Mateika
- John D. Dingell Veterans Affairs Medical Center, Detroit, MI 48201, United States; Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, United States; Department of Internal Medicine, Wayne State University School of Medicine, Detroit, MI 48201, United States.
| | - Dragana Komnenov
- John D. Dingell Veterans Affairs Medical Center, Detroit, MI 48201, United States; Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, United States
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26
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Sforza E, Roche F. Chronic intermittent hypoxia and obstructive sleep apnea: an experimental and clinical approach. HYPOXIA (AUCKLAND, N.Z.) 2016; 4:99-108. [PMID: 27800512 PMCID: PMC5085272 DOI: 10.2147/hp.s103091] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Obstructive sleep apnea (OSA) is a prevalent sleep disorder considered as an independent risk factor for cardiovascular consequences, such as systemic arterial hypertension, ischemic heart disease, cardiac arrhythmias, metabolic disorders, and cognitive dysfunction. The pathogenesis of OSA-related consequence is assumed to be chronic intermittent hypoxia (IH) inducing alterations at the molecular level, oxidative stress, persistent systemic inflammation, oxygen sensor activation, and increase of sympathetic activity. Overall, these mechanisms have an effect on vessel permeability and are considered to be important factors for explaining vascular, metabolic, and cognitive OSA-related consequences. The present review attempts to examine together the research paradigms and clinical studies on the effect of acute and chronic IH and the potential link with OSA. We firstly describe the literature data on the mechanisms activated by acute and chronic IH at the experimental level, which are very helpful and beneficial to explaining OSA consequences. Then, we describe in detail the effect of IH in patients with OSA that we can consider "the human model" of chronic IH. In this way, we can better understand the specific pathophysiological mechanisms proposed to explain the consequences of IH in OSA.
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Affiliation(s)
- Emilia Sforza
- Service de Physiologie Clinique et de l’Exercice, Pole NOL, CHU, EA SNA-EPIS 4607, Faculté de Médecine J. Lisfranc, UJM Saint-Etienne, Université de Lyon, Saint-Etienne, France
| | - Fréderic Roche
- Service de Physiologie Clinique et de l’Exercice, Pole NOL, CHU, EA SNA-EPIS 4607, Faculté de Médecine J. Lisfranc, UJM Saint-Etienne, Université de Lyon, Saint-Etienne, France
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27
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Farías JG, Herrera EA, Carrasco-Pozo C, Sotomayor-Zárate R, Cruz G, Morales P, Castillo RL. Pharmacological models and approaches for pathophysiological conditions associated with hypoxia and oxidative stress. Pharmacol Ther 2015; 158:1-23. [PMID: 26617218 DOI: 10.1016/j.pharmthera.2015.11.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Hypoxia is the failure of oxygenation at the tissue level, where the reduced oxygen delivered is not enough to satisfy tissue demands. Metabolic depression is the physiological adaptation associated with reduced oxygen consumption, which evidently does not cause any harm to organs that are exposed to acute and short hypoxic insults. Oxidative stress (OS) refers to the imbalance between the generation of reactive oxygen species (ROS) and the ability of endogenous antioxidant systems to scavenge ROS, where ROS overwhelms the antioxidant capacity. Oxidative stress plays a crucial role in the pathogenesis of diseases related to hypoxia during intrauterine development and postnatal life. Thus, excessive ROS are implicated in the irreversible damage to cell membranes, DNA, and other cellular structures by oxidizing lipids, proteins, and nucleic acids. Here, we describe several pathophysiological conditions and in vivo and ex vivo models developed for the study of hypoxic and oxidative stress injury. We reviewed existing literature on the responses to hypoxia and oxidative stress of the cardiovascular, renal, reproductive, and central nervous systems, and discussed paradigms of chronic and intermittent hypobaric hypoxia. This systematic review is a critical analysis of the advantages in the application of some experimental strategies and their contributions leading to novel pharmacological therapies.
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Affiliation(s)
- Jorge G Farías
- Facultad de Ingeniería y Ciencias, Departamento de Ingeniería Química, Universidad de la Frontera, Casilla 54-D, Temuco, Chile
| | - Emilio A Herrera
- Programa de Fisiopatología, ICBM, Facultad de Medicina, Universidad de Chile, Chile; International Center for Andean Studies (INCAS), Universidad de Chile, Chile
| | | | - Ramón Sotomayor-Zárate
- Centro de Neurobiología y Plasticidad Cerebral (CNPC), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Chile
| | - Gonzalo Cruz
- Centro de Neurobiología y Plasticidad Cerebral (CNPC), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Chile
| | - Paola Morales
- Programa de Farmacología Molecular y Clínica, ICBM, Facultad de Medicina, Universidad de Chile, Chile
| | - Rodrigo L Castillo
- Programa de Fisiopatología, ICBM, Facultad de Medicina, Universidad de Chile, Chile.
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HOLZEROVÁ K, HLAVÁČKOVÁ M, ŽURMANOVÁ J, BORCHERT G, NECKÁŘ J, KOLÁŘ F, NOVÁK F, NOVÁKOVÁ O. Involvement of PKCε in Cardioprotection Induced by Adaptation to Chronic Continuous Hypoxia. Physiol Res 2015; 64:191-201. [DOI: 10.33549/physiolres.932860] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Continuous normobaric hypoxia (CNH) renders the heart more tolerant to acute ischemia/reperfusion injury. Protein kinase C (PKC) is an important component of the protective signaling pathway, but the contribution of individual PKC isoforms under different hypoxic conditions is poorly understood. The aim of this study was to analyze the expression of PKCε after the adaptation to CNH and to clarify its role in increased cardiac ischemic tolerance with the use of PKCε inhibitory peptide KP-1633. Adult male Wistar rats were exposed to CNH (10 % O2, 3 weeks) or kept under normoxic conditions. The protein level of PKCε and its phosphorylated form was analyzed by Western blot in homogenate, cytosolic and particulate fractions; the expression of PKCε mRNA was measured by RT-PCR. The effect of KP-1633 on cell viability and lactate dehydrogenase (LDH) release was analyzed after 25-min metabolic inhibition followed by 30-min re-energization in freshly isolated left ventricular myocytes. Adaptation to CNH increased myocardial PKCε at protein and mRNA levels. The application of KP-1633 blunted the hypoxia-induced salutary effects on cell viability and LDH release, while control peptide KP-1723 had no effect. This study indicates that PKCε is involved in the cardioprotective mechanism induced by CNH.
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Affiliation(s)
| | - M. HLAVÁČKOVÁ
- Department of Developmental Cardiology, Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
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Verges S, Chacaroun S, Godin-Ribuot D, Baillieul S. Hypoxic Conditioning as a New Therapeutic Modality. Front Pediatr 2015; 3:58. [PMID: 26157787 PMCID: PMC4476260 DOI: 10.3389/fped.2015.00058] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 06/03/2015] [Indexed: 01/03/2023] Open
Abstract
Preconditioning refers to a procedure by which a single noxious stimulus below the threshold of damage is applied to the tissue in order to increase resistance to the same or even different noxious stimuli given above the threshold of damage. Hypoxic preconditioning relies on complex and active defenses that organisms have developed to counter the adverse consequences of oxygen deprivation. The protection it confers against ischemic attack for instance as well as the underlying biological mechanisms have been extensively investigated in animal models. Based on these data, hypoxic conditioning (consisting in recurrent exposure to hypoxia) has been suggested a potential non-pharmacological therapeutic intervention to enhance some physiological functions in individuals in whom acute or chronic pathological events are anticipated or existing. In addition to healthy subjects, some benefits have been reported in patients with cardiovascular and pulmonary diseases as well as in overweight and obese individuals. Hypoxic conditioning consisting in sessions of intermittent exposure to moderate hypoxia repeated over several weeks may induce hematological, vascular, metabolic, and neurological effects. This review addresses the existing evidence regarding the use of hypoxic conditioning as a potential therapeutic modality, and emphasizes on many remaining issues to clarify and future researches to be performed in the field.
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Affiliation(s)
- Samuel Verges
- Laboratoire HP2, Université Grenoble Alpes , Grenoble , France ; U1042, INSERM , Grenoble , France
| | - Samarmar Chacaroun
- Laboratoire HP2, Université Grenoble Alpes , Grenoble , France ; U1042, INSERM , Grenoble , France
| | - Diane Godin-Ribuot
- Laboratoire HP2, Université Grenoble Alpes , Grenoble , France ; U1042, INSERM , Grenoble , France
| | - Sébastien Baillieul
- Laboratoire HP2, Université Grenoble Alpes , Grenoble , France ; U1042, INSERM , Grenoble , France
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Zhang P, Shi X, Downey HF. Two-week normobaric intermittent-hypoxic exposures stabilize cerebral perfusion during hypocapnia and hypercapnia. Exp Biol Med (Maywood) 2014; 240:961-8. [PMID: 25504012 DOI: 10.1177/1535370214562339] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 10/14/2014] [Indexed: 11/15/2022] Open
Abstract
The effect of moderately extended, intermittent-hypoxia (IH) on cerebral perfusion during changes in CO2 was unknown. Thus, we assessed the changes in cerebral vascular conductance (CVC) and cerebral tissue oxygenation (ScO2) during experimental hypocapnia and hypercapnia following 14-day normobaric exposures to IH (10% O2). CVC was estimated from the ratio of mean middle cerebral arterial blood flow velocity (transcranial Doppler sonography) to mean arterial pressure (tonometry), and ScO2 in the prefrontal cortex was monitored by near-infrared spectroscopy. Changes in CVC and ScO2 during changes in partial pressure of end-tidal CO2 (PETCO2, mass spectrometry) induced by 30-s paced-hyperventilation (hypocapnia) and during 6-min CO2 rebreathing (hypercapnia) were compared before and after 14-day IH exposures in eight young nonsmokers. Repetitive IH exposures reduced the ratio of %ΔCVC/ΔPETCO2 during hypocapnia (1.00 ± 0.13 vs 1.94 ± 0.35 vs %/mmHg, P = 0.026) and the slope of ΔCVC/ΔPETCO2 during hypercapnia (1.79 ± 0.37 vs 2.97 ± 0.64 %/mmHg, P = 0.021), but had no significant effect on ΔScO2/ΔPETCO2. The ventilatory response to hypercapnia during CO2 rebreathing was significantly diminished following 14-day IH exposures (0.83 ± 0.07 vs 1.14 ± 0.09 L/min/mmHg, P = 0.009). We conclude that repetitive normobaric IH exposures significantly diminish variations of cerebral perfusion in response to hypercapnia and hypocapnia without compromising cerebral tissue oxygenation. This IH-induced blunting of cerebral vasoreactivity during CO2 variations helps buffer excessive oscillations of cerebral underperfusion and overperfusion while sustaining cerebral O2 homeostasis.
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Affiliation(s)
- Peizhen Zhang
- Department of Integrative Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA Beijing Sport University, Beijing 100084, China
| | - Xiangrong Shi
- Department of Integrative Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA Cardiovascular Research Institute, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - H Fred Downey
- Department of Integrative Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA Cardiovascular Research Institute, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
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Navarrete-Opazo A, Mitchell GS. Therapeutic potential of intermittent hypoxia: a matter of dose. Am J Physiol Regul Integr Comp Physiol 2014; 307:R1181-97. [PMID: 25231353 DOI: 10.1152/ajpregu.00208.2014] [Citation(s) in RCA: 290] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Intermittent hypoxia (IH) has been the subject of considerable research in recent years, and triggers a bewildering array of both detrimental and beneficial effects in multiple physiological systems. Here, we review the extensive literature concerning IH and its impact on the respiratory, cardiovascular, immune, metabolic, bone, and nervous systems. One major goal is to define relevant IH characteristics leading to safe, protective, and/or therapeutic effects vs. pathogenesis. To understand the impact of IH, it is essential to define critical characteristics of the IH protocol under investigation, including potentially the severity of hypoxia within episodes, the duration of hypoxic episodes, the number of hypoxic episodes per day, the pattern of presentation across time (e.g., within vs. consecutive vs. alternating days), and the cumulative time of exposure. Not surprisingly, severe/chronic IH protocols tend to be pathogenic, whereas any beneficial effects are more likely to arise from modest/acute IH exposures. Features of the IH protocol most highly associated with beneficial vs. pathogenic outcomes include the level of hypoxemia within episodes and the number of episodes per day. Modest hypoxia (9-16% inspired O2) and low cycle numbers (3-15 episodes per day) most often lead to beneficial effects without pathology, whereas severe hypoxia (2-8% inspired O2) and more episodes per day (48-2,400 episodes/day) elicit progressively greater pathology. Accumulating evidence suggests that "low dose" IH (modest hypoxia, few episodes) may be a simple, safe, and effective treatment with considerable therapeutic potential for multiple clinical disorders.
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Affiliation(s)
- Angela Navarrete-Opazo
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin
| | - Gordon S Mitchell
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin
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Zhang P, Downey HF, Chen S, Shi X. Two-week normobaric intermittent hypoxia exposures enhance oxyhemoglobin equilibrium and cardiac responses during hypoxemia. Am J Physiol Regul Integr Comp Physiol 2014; 307:R721-30. [PMID: 25056104 DOI: 10.1152/ajpregu.00191.2014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Intermittent hypoxia (IH) is extensively applied to challenge cardiovascular and respiratory function, and to induce physiological acclimatization. The purpose of this study was to test the hypothesis that oxyhemoglobin equilibrium and tachycardiac responses during hypoxemia were enhanced after 14-day IH exposures. Normobaric-poikilocapnic hypoxia was induced with inhalation of 10% O2 for 5-6 min interspersed with 4 min recovery on eight nonsmokers. Heart rate (HR), arterial O2 saturation (SaO 2), and end-tidal O2 (PetO 2) were continuously monitored during cyclic normoxia and hypoxia. These variables were compared during the first and fifth hypoxic bouts between day 1 and day 14. There was a rightward shift in the oxyhemoglobin equilibrium response following 14-day IH exposures, as indicated by the greater PetO 2 (an index of arterial Po2) at 50% of SaO 2 on day 14 compared with day 1 [33.9 ± 1.5 vs. 28.2 ± 1.3 mmHg (P = 0.005) during the first hypoxic bout and 39.4 ± 2.4 vs. 31.4 ± 1.5 mmHg (P = 0.006) during the fifth hypoxic bout] and by the augmented gains of ΔSaO 2/ΔPetO 2 (i.e., deoxygenation) during PetO 2 from 65 to 40 mmHg in the first (1.12 ± 0.08 vs. 0.80 ± 0.02%/mmHg, P = 0.001) and the fifth (1.76 ± 0.31 vs. 1.05 ± 0.06%/mmHg, P = 0.024) hypoxic bouts. Repetitive IH exposures attenuated (P = 0.049) the tachycardiac response to hypoxia while significantly enhancing normoxic R-R interval variability in low-frequency and high-frequency spectra without changes in arterial blood pressure at rest or during hypoxia. We conclude that 14-day IH exposures enhance arterial O2 delivery and improve vagal control of HR during hypoxic hypoxemia.
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Affiliation(s)
- Peizhen Zhang
- Department of Integrative Physiology, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas; Beijing Sport University, Beijing, China
| | - H Fred Downey
- Department of Integrative Physiology, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas; Cardiovascular Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas; and
| | - Shande Chen
- Department of Biostatistics, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas
| | - Xiangrong Shi
- Department of Integrative Physiology, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas; Cardiovascular Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas; and
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Almendros I, Wang Y, Gozal D. The polymorphic and contradictory aspects of intermittent hypoxia. Am J Physiol Lung Cell Mol Physiol 2014; 307:L129-40. [PMID: 24838748 DOI: 10.1152/ajplung.00089.2014] [Citation(s) in RCA: 128] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Intermittent hypoxia (IH) has been extensively studied during the last decade, primarily as a surrogate model of sleep apnea. However, IH is a much more pervasive phenomenon in human disease, is viewed as a potential therapeutic approach, and has also been used in other disciplines, such as in competitive sports. In this context, adverse outcomes involving cardiovascular, cognitive, metabolic, and cancer problems have emerged in obstructive sleep apnea-based studies, whereas beneficial effects of IH have also been identified. Those a priori contradictory findings may not be as contradictory as initially thought. Indeed, the opposite outcomes triggered by IH can be explained by the specific characteristics of the large diversity of IH patterns applied in each study. The balance between benefits and injury appears to primarily depend on the ability of the organism to respond and activate adaptive mechanisms to IH. In this context, the adaptive or maladaptive responses can be generally predicted by the frequency, severity, and duration of IH. However, the presence of underlying conditions such as hypertension or obesity, as well as age, sex, or genotypic variance, may be important factors tilting the balance between an appropriate homeostatic response and decompensation. Here, the two possible facets of IH as derived from human and experimental animal settings will be reviewed.
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Affiliation(s)
- Isaac Almendros
- Department of Pediatrics, Comer Children's Hospital, Pritzker School of Medicine, The University of Chicago, Chicago, Illinois
| | - Yang Wang
- Department of Pediatrics, Comer Children's Hospital, Pritzker School of Medicine, The University of Chicago, Chicago, Illinois
| | - David Gozal
- Department of Pediatrics, Comer Children's Hospital, Pritzker School of Medicine, The University of Chicago, Chicago, Illinois
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