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Liu N, Chen Y, Wang Y, Wu S, Wang J, Qi L, Deng T, Xia L. The underlying mechanisms of DNA methylation in high salt memory in hypertensive vascular disease. Sci Rep 2024; 14:925. [PMID: 38195688 PMCID: PMC10776617 DOI: 10.1038/s41598-024-51279-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 01/03/2024] [Indexed: 01/11/2024] Open
Abstract
This study demonstrates the effect and DNA methylation-related mechanisms of a high-salt diet and salt memory-induced hypertension and vasculopathy. Thirty Sprague Dawley rats were randomly divided into a control (CON) group (n = 6) and a modeling group (n = 24). A 12% NaCl solution (1 mL/100 g) was intragastrically administered for 60 consecutive days for modeling. An increase in blood pressure up to 140 mmHg was considered successful modeling. Twelve of fifteen successfully modeled rats were randomly selected and divided into a High Salt Diet (HSD) group and a High Salt Memory (HSM) group (n = 6). Rats in HSD group were intragastrically administered a 12% NaCl solution, while rats in HSM group were administered a 3% NaCl solution twice a day for 30 days. At the end of the intervention, blood pressure and the serum levels of ET-1, NO, TNF-α and IL-1β were measured. RRBS-heavy sulfite sequencing technology was selected for DNA methylation analysis. The systolic blood pressure of rats in the HSD group and HSM group was significantly higher than that in the CON group. Compared with those in the CON group, the serum levels of ET-1 in the HSM group and the serum levels of NO in the HSD group and HSM group were significantly increased. The methylation level of the CON group was lower than that of the HSD group and the HSM group, and there was no significant difference between the HSD group and the HSM group. The methylation level of Myoz3 was downregulated in the HSD group and HSM group. The methylation level of Fgd3 were upregulated in HSD group and downregulated in the HSM group. The methylation levels of AC095693.1, Adamts3, PDGFA and PDGFRα were downregulated in the HSD group and upregulated in the HSM group. According to the GO database, the differentially methylated genes were significantly enriched in the coordination of cell function, genetic development, and RNA transcription. There were three main metabolic pathways that were enriched in the differentially expressed genes between the groups: the PI3K-Akt signaling pathway, MAPK signaling pathway, and Hippo signaling pathway. Excessive salt intake may cause hypertension and vascular damage, and this damage may continue after the reduction of salt intake. Therefore, salt memory phenomenon exists, and this memory effect may be correlated with the levels of DNA methylation.
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Affiliation(s)
- Nannan Liu
- College of Health and Rehabilitation, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Yixiao Chen
- College of Health and Rehabilitation, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Yuhan Wang
- Child Mental Health Research Center, Nanjing Brain Hospital Affiliated of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Sha Wu
- College of Health and Rehabilitation, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Jie Wang
- College of Health and Rehabilitation, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Luming Qi
- College of Health and Rehabilitation, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Tingting Deng
- College of Nursing, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Lina Xia
- College of Health and Rehabilitation, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, 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: 0] [Impact Index Per Article: 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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Mancardi D, Ottolenghi S, Attanasio U, Tocchetti CG, Paroni R, Pagliaro P, Samaja M. Janus, or the Inevitable Battle Between Too Much and Too Little Oxygen. Antioxid Redox Signal 2022; 37:972-989. [PMID: 35412859 DOI: 10.1089/ars.2021.0232] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Significance: Oxygen levels are key regulators of virtually every living mammalian cell, under both physiological and pathological conditions. Starting from embryonic and fetal development, through the growth, onset, and progression of diseases, oxygen is a subtle, although pivotal, mediator of key processes such as differentiation, proliferation, autophagy, necrosis, and apoptosis. Hypoxia-driven modifications of cellular physiology are investigated in depth or for their clinical and translational relevance, especially in the ischemic scenario. Recent Advances: The mild or severe lack of oxygen is, undoubtedly, related to cell death, although abundant evidence points at oscillating oxygen levels, instead of permanent low pO2, as the most detrimental factor. Different cell types can consume oxygen at different rates and, most interestingly, some cells can shift from low to high consumption according to the metabolic demand. Hence, we can assume that, in the intracellular compartment, oxygen tension varies from low to high levels depending on both supply and consumption. Critical Issues: The positive balance between supply and consumption leads to a pro-oxidative environment, with some cell types facing hypoxia/hyperoxia cycles, whereas some others are under fairly constant oxygen tension. Future Directions: Within this frame, the alterations of oxygen levels (dysoxia) are critical in two paradigmatic organs, the heart and brain, under physiological and pathological conditions and the interactions of oxygen with other physiologically relevant gases, such as nitric oxide, can alternatively contribute to the worsening or protection of ischemic organs. Further, the effects of dysoxia are of pivotal importance for iron metabolism. Antioxid. Redox Signal. 37, 972-989.
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Affiliation(s)
- Daniele Mancardi
- Department of Clinical and Biological Sciences, University of Torino, Turin, Italy
| | - Sara Ottolenghi
- Department of Health Sciences, University of Milano, Milan, Italy
- School of Medicine and Surgery, University of Milano Bicocca, Milan, Italy
| | - Umberto Attanasio
- Cardio-Oncology Unit, Department of Translational Medical Sciences, Federico II University, Naples, Italy
| | - Carlo Gabriele Tocchetti
- Cardio-Oncology Unit, Department of Translational Medical Sciences, Federico II University, Naples, Italy
- Interdepartmental Center for Clinical and Translational Research (CIRCET), Federico II University, Naples, Italy
- Interdepartmental Hypertension Research Center (CIRIAPA), Federico II University, Naples, Italy
- Center for Basic and Clinical Immunology Research (CISI), Federico II University, Naples, Italy
| | - Rita Paroni
- Department of Health Sciences, University of Milano, Milan, Italy
| | - Pasquale Pagliaro
- Department of Clinical and Biological Sciences, University of Torino, Turin, Italy
| | - Michele Samaja
- Department of Health Sciences, University of Milano, Milan, Italy
- MAGI GROUP, San Felice del Benaco, Italy
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Walkowski B, Kleibert M, Majka M, Wojciechowska M. Insight into the Role of the PI3K/Akt Pathway in Ischemic Injury and Post-Infarct Left Ventricular Remodeling in Normal and Diabetic Heart. Cells 2022; 11:cells11091553. [PMID: 35563860 PMCID: PMC9105930 DOI: 10.3390/cells11091553] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/28/2022] [Accepted: 05/03/2022] [Indexed: 02/07/2023] Open
Abstract
Despite the significant decline in mortality, cardiovascular diseases are still the leading cause of death worldwide. Among them, myocardial infarction (MI) seems to be the most important. A further decline in the death rate may be achieved by the introduction of molecularly targeted drugs. It seems that the components of the PI3K/Akt signaling pathway are good candidates for this. The PI3K/Akt pathway plays a key role in the regulation of the growth and survival of cells, such as cardiomyocytes. In addition, it has been shown that the activation of the PI3K/Akt pathway results in the alleviation of the negative post-infarct changes in the myocardium and is impaired in the state of diabetes. In this article, the role of this pathway was described in each step of ischemia and subsequent left ventricular remodeling. In addition, we point out the most promising substances which need more investigation before introduction into clinical practice. Moreover, we present the impact of diabetes and widely used cardiac and antidiabetic drugs on the PI3K/Akt pathway and discuss the molecular mechanism of its effects on myocardial ischemia and left ventricular remodeling.
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Affiliation(s)
- Bartosz Walkowski
- Laboratory of Centre for Preclinical Research, Department of Experimental and Clinical Physiology, Medical University of Warsaw, Banacha 1b, 02-097 Warsaw, Poland; (B.W.); (M.W.)
| | - Marcin Kleibert
- Laboratory of Centre for Preclinical Research, Department of Experimental and Clinical Physiology, Medical University of Warsaw, Banacha 1b, 02-097 Warsaw, Poland; (B.W.); (M.W.)
- Correspondence: (M.K.); (M.M.)
| | - Miłosz Majka
- Laboratory of Centre for Preclinical Research, Department of Experimental and Clinical Physiology, Medical University of Warsaw, Banacha 1b, 02-097 Warsaw, Poland; (B.W.); (M.W.)
- Correspondence: (M.K.); (M.M.)
| | - Małgorzata Wojciechowska
- Laboratory of Centre for Preclinical Research, Department of Experimental and Clinical Physiology, Medical University of Warsaw, Banacha 1b, 02-097 Warsaw, Poland; (B.W.); (M.W.)
- Invasive Cardiology Unit, Independent Public Specialist Western Hospital John Paul II, Daleka 11, 05-825 Grodzisk Mazowiecki, Poland
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5
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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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6
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Lopez-Pascual A, Trayhurn P, Martínez JA, González-Muniesa P. Oxygen in Metabolic Dysfunction and Its Therapeutic Relevance. Antioxid Redox Signal 2021; 35:642-687. [PMID: 34036800 DOI: 10.1089/ars.2019.7901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Significance: In recent years, a number of studies have shown altered oxygen partial pressure at a tissue level in metabolic disorders, and some researchers have considered oxygen to be a (macro) nutrient. Oxygen availability may be compromised in obesity and several other metabolism-related pathological conditions, including sleep apnea-hypopnea syndrome, the metabolic syndrome (which is a set of conditions), type 2 diabetes, cardiovascular disease, and cancer. Recent Advances: Strategies designed to reduce adiposity and its accompanying disorders have been mainly centered on nutritional interventions and physical activity programs. However, novel therapies are needed since these approaches have not been sufficient to counteract the worldwide increasing rates of metabolic disorders. In this regard, intermittent hypoxia training and hyperoxia could be potential treatments through oxygen-related adaptations. Moreover, living at a high altitude may have a protective effect against the development of abnormal metabolic conditions. In addition, oxygen delivery systems may be of therapeutic value for supplying the tissue-specific oxygen requirements. Critical Issues: Precise in vivo methods to measure oxygenation are vital to disentangle some of the controversies related to this research area. Further, it is evident that there is a growing need for novel in vitro models to study the potential pathways involved in metabolic dysfunction to find appropriate therapeutic targets. Future Directions: Based on the existing evidence, it is suggested that oxygen availability has a key role in obesity and its related comorbidities. Oxygen should be considered in relation to potential therapeutic strategies in the treatment and prevention of metabolic disorders. Antioxid. Redox Signal. 35, 642-687.
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Affiliation(s)
- Amaya Lopez-Pascual
- Department of Nutrition, Food Science and Physiology, School of Pharmacy and Nutrition, Centre for Nutrition Research, University of Navarra, Pamplona, Spain.,Neuroendocrine Cell Biology, Lund University Diabetes Centre, Lund University, Malmö, Sweden
| | - Paul Trayhurn
- Obesity Biology Unit, University of Liverpool, Liverpool, United Kingdom.,Clore Laboratory, The University of Buckingham, Buckingham, United Kingdom
| | - J Alfredo Martínez
- Department of Nutrition, Food Science and Physiology, School of Pharmacy and Nutrition, Centre for Nutrition Research, University of Navarra, Pamplona, Spain.,IdiSNA, Navarra Institute for Health Research, Pamplona, Spain.,CIBERobn Physiopathology of Obesity and Nutrition, Centre of Biomedical Research Network, ISCIII, Madrid, Spain.,Precision Nutrition and Cardiometabolic Health, IMDEA Food, Madrid Institute for Advanced Studies, Madrid, Spain
| | - Pedro González-Muniesa
- Department of Nutrition, Food Science and Physiology, School of Pharmacy and Nutrition, Centre for Nutrition Research, University of Navarra, Pamplona, Spain.,IdiSNA, Navarra Institute for Health Research, Pamplona, Spain.,CIBERobn Physiopathology of Obesity and Nutrition, Centre of Biomedical Research Network, ISCIII, Madrid, Spain
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7
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Reinero M, Beghetti M, Tozzi P, Segesser LKV, Samaja M, Milano G. Nitric Oxide-cGMP Pathway Modulation in an Experimental Model of Hypoxic Pulmonary Hypertension. J Cardiovasc Pharmacol Ther 2021; 26:665-676. [PMID: 33969747 PMCID: PMC8547238 DOI: 10.1177/10742484211014162] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Manipulation of nitric oxide (NO) may enable control of progression and treatment of pulmonary hypertension (PH). Several approaches may modulate the NO-cGMP pathway in vivo. Here, we investigate the effectiveness of 3 modulatory sites: (i) the amount of l-arginine; (ii) the size of plasma NO stores that stimulate soluble guanylate cyclase; (iii) the conversion of cGMP into inactive 5′-GMP, with respect to hypoxia, to test the effectiveness of the treatments with respect to hypoxia-induced PH. Male rats (n = 80; 10/group) maintained in normoxic (21% O2) or hypoxic chambers (10% O2) for 14 days were subdivided in 4 sub-groups: placebo, l-arginine (20 mg/ml), the NO donor molsidomine (15 mg/kg in drinking water), and phoshodiesterase-5 inhibitor sildenafil (1.4 mg/kg in 0.3 ml saline, i.p.). Hypoxia depressed homeostasis and increased erythropoiesis, heart and right ventricle hypertrophy, myocardial fibrosis and apoptosis inducing pulmonary remodeling. Stimulating anyone of the 3 mechanisms that enhance the NO-cGMP pathway helped rescuing the functional and morphological changes in the cardiopulmonary system leading to improvement, sometimes normalization, of the pressures. None of the treatments affected the observed parameters in normoxia. Thus, the 3 modulatory sites are essentially similar in enhancing the NO-cGMP pathway, thereby attenuating the hypoxia-related effects that lead to pulmonary hypertension.
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Affiliation(s)
- Melanie Reinero
- Department Cœur-Vaisseaux, Cardiac Surgery Center, 30635University Hospital of Lausanne, Lausanne, Switzerland
| | - Maurice Beghetti
- Unité de Cardiologie Pédiatrique, 30538University Hospital of Geneva and Centre Universitaire Romand de Cardiologie et Chirurgie Cardiaque Pédiatrique University of Geneva and Lausanne, Switzerland
| | - Piergiorgio Tozzi
- Department Cœur-Vaisseaux, Cardiac Surgery Center, 30635University Hospital of Lausanne, Lausanne, Switzerland
| | - Ludwig K von Segesser
- Department of Surgery and Anesthesiology, Cardio-Vascular Research, Lausanne, Switzerland
| | - Michele Samaja
- Department of Health Science, 9304University of Milano, Milan, Italy
| | - Giuseppina Milano
- Department Cœur-Vaisseaux, Cardiac Surgery Center, 30635University Hospital of Lausanne, Lausanne, Switzerland
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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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9
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Naryzhnaya NV, Ma HJ, Maslov LN. The involvement of protein kinases in the cardioprotective effect of chronic hypoxia. Physiol Res 2020; 69:933-945. [PMID: 33129243 DOI: 10.33549/physiolres.934439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The purpose of this review is to analyze the involvement of protein kinases in the cardioprotective mechanism induced by chronic hypoxia. It has been reported that chronic intermittent hypoxia contributes to increased expression of the following kinases in the myocardium: PKCdelta, PKCalpha, p-PKCepsilon, p-PKCalpha, AMPK, p-AMPK, CaMKII, p-ERK1/2, p-Akt, PI3-kinase, p-p38, HK-1, and HK-2; whereas, chronic normobaric hypoxia promotes increased expression of the following kinases in the myocardium: PKCepsilon, PKCbetaII, PKCeta, CaMKII, p-ERK1/2, p-Akt, p-p38, HK-1, and HK-2. However, CNH does not promote enhanced expression of the AMPK and JNK kinases. Adaptation to hypoxia enhances HK-2 association with mitochondria and causes translocation of PKCdelta, PKCbetaII, and PKCeta to the mitochondria. It has been shown that PKCdelta, PKCepsilon, ERK1/2, and MEK1/2 are involved in the cardioprotective effect of chronic hypoxia. The role of other kinases in the cardioprotective effect of adaptation to hypoxia requires further research.
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Affiliation(s)
- N V Naryzhnaya
- Cardiology Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk, Russia.
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10
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Li X, Yang T, Sun Z. Hormesis in Health and Chronic Diseases. Trends Endocrinol Metab 2019; 30:944-958. [PMID: 31521464 PMCID: PMC6875627 DOI: 10.1016/j.tem.2019.08.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 08/12/2019] [Accepted: 08/16/2019] [Indexed: 12/25/2022]
Abstract
'What doesn't kill you makes you stronger'. Hormesis, the paradoxical beneficial effects of low-dose stressors, can be better defined as the biphasic dose-effect or time-effect relationship for any substance. Here we review hormesis-like phenomena in the context of chronic diseases for many substances, including lifestyle factors and endocrine factors. Intermittent or pulsatile exposure can generate opposite effects compared with continuous exposure. An initial exposure can elicit an adaptive stress response with long-lasting protection against subsequent exposures. Early-life stress can increase resilience in later life and lack of stress can lead to vulnerability. Many stressors are naturally occurring and are required for healthy growth or homeostasis, which exemplifies how 'illness is the doorway to health'.
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Affiliation(s)
- Xin Li
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, Baylor College of Medicine, Houston, TX, USA
| | - Tingting Yang
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, Baylor College of Medicine, Houston, TX, USA; Department of Pediatrics, Children's Nutrition Research Center, Baylor College of Medicine, Houston, TX, USA
| | - Zheng Sun
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, Baylor College of Medicine, Houston, TX, USA; Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA.
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11
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Macrophage migration inhibitory factor plays an essential role in ischemic preconditioning-mediated cardioprotection. Clin Sci (Lond) 2019; 133:665-680. [PMID: 30804219 DOI: 10.1042/cs20181013] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 01/26/2019] [Accepted: 02/22/2019] [Indexed: 12/23/2022]
Abstract
Ischemic preconditioning (IPC) is an endogenous protection strategy against myocardial ischemia-reperfusion (I/R) injury. Macrophage migration inhibitory factor (MIF) released from the myocardium subjected to brief periods of ischemia confers cardioprotection. We hypothesized that MIF plays an essential role in IPC-induced cardioprotection. I/R was induced either ex vivo or in vivo in male wild-type (WT) and MIF knockout (MIFKO) mice with or without proceeding IPC (three cycles of 5-min ischemia and 5-min reperfusion). Indices of myocardial injury, regional inflammation and cardiac function were determined to evaluate the extent of I/R injury. Activations of the reperfusion injury salvage kinase (RISK) pathway, AMP-activated protein kinase (AMPK) and their downstream components were investigated to explore the underlying mechanisms. IPC conferred prominent protection in WT hearts evidenced by reduced infarct size (by 33-35%), myocyte apoptosis and enzymatic markers of tissue injury, ROS production, inflammatory cell infiltration and MCP1/CCR2 expression (all P<0.05). IPC also ameliorated cardiac dysfunction both ex vivo and in vivo These protective effects were abolished in MIFKO hearts. Notably, IPC mediated further activations of RISK pathway, AMPK and the membrane translocation of GLUT4 in WT hearts. Deletion of MIF blunted these changes in response to IPC, which is the likely basis for the absence of protective effects of IPC against I/R injury. In conclusion, MIF plays a critical role in IPC-mediated cardioprotection under ischemic stress by activating RISK signaling pathway and AMPK. These results provide an insight for developing a novel therapeutic strategy that target MIF to protect ischemic hearts.
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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: 58] [Impact Index Per Article: 9.7] [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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13
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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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Casieri V, Matteucci M, Cavallini C, Torti M, Torelli M, Lionetti V. Long-term Intake of Pasta Containing Barley (1-3)Beta-D-Glucan Increases Neovascularization-mediated Cardioprotection through Endothelial Upregulation of Vascular Endothelial Growth Factor and Parkin. Sci Rep 2017; 7:13424. [PMID: 29044182 PMCID: PMC5647408 DOI: 10.1038/s41598-017-13949-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 10/03/2017] [Indexed: 01/17/2023] Open
Abstract
Barley (1-3)β-D-Glucan (BBG) enhances angiogenesis. Since pasta is very effective in providing a BBG-enriched diet, we hypothesized that the intake of pasta containing 3% BBG (P-BBG) induces neovascularization-mediated cardioprotection. Healthy adult male C57BL/6 mice fed P-BBG (n = 15) or wheat pasta (Control, n = 15) for five-weeks showed normal glucose tolerance and cardiac function. With a food intake similar to the Control, P-BBG mice showed a 109% survival rate (P < 0.01 vs. Control) after cardiac ischemia (30 min)/reperfusion (60 min) injury. Left ventricular (LV) anion superoxide production and infarct size in P-BBG mice were reduced by 62 and 35% (P < 0.0001 vs. Control), respectively. The capillary and arteriolar density of P-BBG hearts were respectively increased by 12 and 18% (P < 0.05 vs. Control). Compared to the Control group, the VEGF expression in P-BBG hearts was increased by 87.7% (P < 0.05); while, the p53 and Parkin expression was significantly increased by 125% and cleaved caspase-3 levels were reduced by 33% in P-BBG mice. In vitro, BBG was required to induce VEGF, p53 and Parkin expression in human umbelical vascular endothelial cells. Moreover, the BBG-induced Parkin expression was not affected by pifithrin-α (10 uM/7days), a p53 inhibitor. In conclusion, long-term dietary supplementation with P-BBG confers post-ischemic cardioprotection through endothelial upregulation of VEGF and Parkin.
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Affiliation(s)
| | - Marco Matteucci
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Claudia Cavallini
- ATTRE (Advanced Therapies and Tissue Regeneration) Laboratory, Innovation Accelerator CNR, Bologna, Italy
| | - Milena Torti
- Research and Development Unit, Pastificio Attilio Matromauro Granoro s.r.l, Corato, Italy
| | - Michele Torelli
- Research and Development Unit, Pastificio Attilio Matromauro Granoro s.r.l, Corato, Italy
| | - Vincenzo Lionetti
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy. .,UOS Anesthesia and Intensive Care, Fondazione Toscana "G. Monasterio", Pisa, Italy.
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15
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Favre S, Gambini E, Nigro P, Scopece A, Bianciardi P, Caretti A, Pompilio G, Corno AF, Vassalli G, von Segesser LK, Samaja M, Milano G. Sildenafil attenuates hypoxic pulmonary remodelling by inhibiting bone marrow progenitor cells. J Cell Mol Med 2016; 21:871-880. [PMID: 27860185 PMCID: PMC5387166 DOI: 10.1111/jcmm.13026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 09/26/2016] [Indexed: 01/26/2023] Open
Abstract
The recruitment of bone marrow (BM)-derived progenitor cells to the lung is related to pulmonary remodelling and the pathogenesis of pulmonary hypertension (PH). Although sildenafil is a known target in PH treatment, the underlying molecular mechanism is still elusive. To test the hypothesis that the therapeutic effect of sildenafil is linked to the reduced recruitment of BM-derived progenitor cells, we induced pulmonary remodelling in rats by two-week exposure to chronic hypoxia (CH, 10% oxygen), a trigger of BM-derived progenitor cells. Rats were treated with either placebo (saline) or sildenafil (1.4 mg/kg/day ip) during CH. Control rats were kept in room air (21% oxygen) with no treatment. As expected, sildenafil attenuated the CH-induced increase in right ventricular systolic pressure and right ventricular hypertrophy. However, sildenafil suppressed the CH-induced increase in c-kit+ cells in the adventitia of pulmonary arteries. Moreover, sildenafil reduced the number of c-kit+ cells that colocalize with tyrosine kinase receptor 2 (VEGF-R2) and CD68 (a marker for macrophages), indicating a positive effect on moderating hypoxia-induced smooth muscle cell proliferation and inflammation without affecting the pulmonary levels of hypoxia-inducible factor (HIF)-1α. Furthermore, sildenafil depressed the number of CXCR4+ cells. Collectively, these findings indicate that the improvement in pulmonary haemodynamic by sildenafil is linked to decreased recruitment of BM-derived c-kit+ cells in the pulmonary tissue. The attenuation of the recruitment of BM-derived c-kit+ cells by sildenafil may provide novel therapeutic insights into the control of pulmonary remodelling.
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Affiliation(s)
- Shirley Favre
- Laboratory of Cardiovascular Research, Department of Surgery and Anesthesiology, University Hospital Lausanne, Lausanne, Switzerland
| | - Elisa Gambini
- Vascular Biology and Regenerative Medicine Unit, Centro Cardiologico Monzino-IRCCS, Milan, Italy
| | - Patrizia Nigro
- Vascular Biology and Regenerative Medicine Unit, Centro Cardiologico Monzino-IRCCS, Milan, Italy
| | - Alessandro Scopece
- Vascular Biology and Regenerative Medicine Unit, Centro Cardiologico Monzino-IRCCS, Milan, Italy
| | | | - Anna Caretti
- Department of Health Science, University of Milan, Milan, Italy
| | - Giulio Pompilio
- Vascular Biology and Regenerative Medicine Unit, Centro Cardiologico Monzino-IRCCS, Milan, Italy
| | | | - Giuseppe Vassalli
- Laboratory of Molecular and Cellular Cardiology, Departments of Cardiology and Heart Surgery, Lausanne, Switzerland
| | - Ludwig K von Segesser
- Laboratory of Cardiovascular Research, Department of Surgery and Anesthesiology, University Hospital Lausanne, Lausanne, Switzerland
| | - Michele Samaja
- Department of Health Science, University of Milan, Milan, Italy
| | - Giuseppina Milano
- Laboratory of Cardiovascular Research, Department of Surgery and Anesthesiology, University Hospital Lausanne, Lausanne, Switzerland.,Vascular Biology and Regenerative Medicine Unit, Centro Cardiologico Monzino-IRCCS, Milan, Italy
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Remifentanil Preconditioning Reduces Postischemic Myocardial Infarction and Improves Left Ventricular Performance via Activation of the Janus Activated Kinase-2/Signal Transducers and Activators of Transcription-3 Signal Pathway and Subsequent Inhibition of Glycogen Synthase Kinase-3β in Rats. Crit Care Med 2016; 44:e131-45. [PMID: 26468894 DOI: 10.1097/ccm.0000000000001350] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVES Remifentanil preconditioning attenuates myocardial ischemia reperfusion injury, but the underlying mechanism is incompletely understood. The Janus activated kinase-2 (JAK2)/signal transducers and activators of transcription-3 (STAT3) and phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathways are critical in both ischemic and pharmacologic preconditioning cardioprotection, which involve the inactivation of glycogen synthase kinase-3β. We hypothesized that remifentanil preconditioning confers cardioprotection via the JAK2/STAT3 and/or PI3K/Akt activation-mediated glycogen synthase kinase-3β inhibition. DESIGN Pharmacologic intervention. SETTING Research laboratory. SUBJECTS Male Sprague-Dawley rats. INTERVENTIONS In vivo and in vitro treatments. MEASUREMENTS AND MAIN RESULTS Male Sprague-Dawley rats (n = 6 per group) were sham operated or subjected to myocardial ischemia reperfusion injury. The JAK2 inhibitor AG490 (3 mg/kg), the PI3K inhibitor wortmannin (15 μg/kg), or the glycogen synthase kinase-3β inhibitor SB216763 (600 μg/kg) were given before inducing in vivo myocardial ischemia reperfusion injury achieved by occluding coronary artery for 30 minutes followed by 120 minutes of reperfusion in the absence or presence of remifentanil preconditioning (6 μg/kg/min). Also, isolated rat hearts were Langendorff perfused and subjected to 30 minutes of global ischemia and 120 minutes of reperfusion without or with remifentanil preconditioning (100 ng/mL) in the presence or absence of AG490 and/or SB216763. Isolated rat cardiomyocytes and H9C2 cells were subjected to hypoxia/reoxygenation alone or in combination with AG490 (100 μM), wortmannin (100 nM), or SB216763 (3 μM) without or with remifentanil preconditioning (2.5 μM). Remifentanil preconditioning reduced postischemic myocardial infarction and hemodynamic dysfunction induced by myocardial ischemia reperfusion injury concomitant with increased phosphorylation of STAT3 at tyr-705 (p-STAT3) and glycogen synthase kinase-3β but not Akt. AG490 but not wortmannin cancelled remifentanil preconditioning cardioprotection, and SB216763 restored it despite the presence of AG490. In Langendorff-perfused hearts, AG490-mediated cancellation of remifentanil preconditioning cardioprotection in attenuating postischemic myocardial infarction and creatinine kinase-MB release was reverted by concomitant administration of SB216763. Remifentanil preconditioning also attenuated posthypoxic cardiomyocyte injury and increased p-STAT3 and glycogen synthase kinase-3β in isolated primary cardiomyocytes and H9C2 cells. STAT3 gene knockdown with specific synthetic RNA cancelled remifentanil preconditioning cardioprotection, whereas glycogen synthase kinase-3β gene knockdown, which per se did not affect STAT3 under hypoxia/reoxygenation condition, preserved remifentanil preconditioning cardioprotection regardless of STAT3 abrogation. CONCLUSIONS Remifentanil preconditioning confers cardioprotection primarily via activation of JAK2/STAT3 signaling that can function independent of PI3K/Akt activation. Glycogen synthase kinase-3β is a critical downstream effector of remifentanil preconditioning cardioprotection.
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Trzepizur W, Gaceb A, Arnaud C, Ribuot C, Levy P, Martinez MC, Gagnadoux F, Andriantsitohaina R. Vascular and hepatic impact of short-term intermittent hypoxia in a mouse model of metabolic syndrome. PLoS One 2015; 10:e0124637. [PMID: 25993257 PMCID: PMC4436258 DOI: 10.1371/journal.pone.0124637] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 03/17/2015] [Indexed: 01/25/2023] Open
Abstract
Background Experimental models of intermittent hypoxia (IH) have been developed during the last decade to investigate the consequences of obstructive sleep apnea. IH is usually associated with detrimental metabolic and vascular outcomes. However, paradoxical protective effects have also been described depending of IH patterns and durations applied in studies. We evaluated the impact of short-term IH on vascular and metabolic function in a diet-induced model of metabolic syndrome (MS). Methods Mice were fed either a standard diet or a high fat diet (HFD) for 8 weeks. During the final 14 days of each diet, animals were exposed to either IH (1 min cycle, FiO2 5% for 30s, FiO2 21% for 30s; 8 h/day) or intermittent air (FiO2 21%). Ex-vivo vascular reactivity in response to acetylcholine was assessed in aorta rings by myography. Glucose, insulin and leptin levels were assessed, as well as serum lipid profile, hepatic mitochondrial activity and tissue nitric oxide (NO) release. Results Mice fed with HFD developed moderate markers of dysmetabolism mimicking MS, including increased epididymal fat, dyslipidemia, hepatic steatosis and endothelial dysfunction. HFD decreased mitochondrial complex I, II and IV activities and increased lactate dehydrogenase (LDH) activity in liver. IH applied to HFD mice induced a major increase in insulin and leptin levels and prevented endothelial dysfunction by restoring NO production. IH also restored mitochondrial complex I and IV activities, moderated the increase in LDH activity and liver triglyceride accumulation in HFD mice. Conclusion In a mouse model of MS, short-term IH increases insulin and leptin levels, restores endothelial function and mitochondrial activity and limits liver lipid accumulation.
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Affiliation(s)
- Wojciech Trzepizur
- INSERM U1063, Sopam, Angers University, F-49045, Angers, France
- Department of Respiratory Diseases, Angers University hospital, Angers, France
- * E-mail:
| | - Abderahim Gaceb
- INSERM U1063, Sopam, Angers University, F-49045, Angers, France
| | - Claire Arnaud
- INSERM U1042, HP2 laboratory, Joseph Fourier University, Grenoble, France
| | - Christophe Ribuot
- INSERM U1042, HP2 laboratory, Joseph Fourier University, Grenoble, France
| | - Patrick Levy
- INSERM U1042, HP2 laboratory, Joseph Fourier University, Grenoble, France
- Laboratoires du Sommeil et EFCR, A. Michallon University Hospital, Grenoble, France
| | | | - Frédéric Gagnadoux
- INSERM U1063, Sopam, Angers University, F-49045, Angers, France
- Department of Respiratory Diseases, Angers University hospital, Angers, France
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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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Güzel D, Dursun AD, Fıçıcılar H, Tekin D, Tanyeli A, Akat F, Topal Çelikkan F, Sabuncuoğlu B, Baştuğ M. Effect of intermittent hypoxia on the cardiac HIF-1/VEGF pathway in experimental type 1 diabetes mellitus. Anatol J Cardiol 2015; 16:76-83. [PMID: 26467365 PMCID: PMC5336740 DOI: 10.5152/akd.2015.5925] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
OBJECTIVE High altitude and hypoxic preconditioning have cardioprotective effects by increasing coronary vascularity, reducing post-ischemic injury, and improving cardiac function. Our purpose was to examine if intermittent hypoxia treatment has any restoring effects related to the possible role of the HIF-1/VEGF pathway on diabetic cardiomyopathy. METHODS Wistar Albino male rats (n=34) were divided into four groups: control (C), intermittent hypoxia (IH), diabetes mellitus (DM), and diabetes mellitus plus intermittent hypoxia (DM+IH). Following a streptozotocin (STZ) injection (50 mg/kg, i.p.), blood glucose levels of 250 mg/dL and above were considered as DM. IH and DM+IH groups were exposed to hypoxia 6 h/day for 42 days at a pressure corresponding to 3000 m altitude. Twenty-four hours after the IH protocol, hearts were excised. Hematoxylin and eosin-stained apical parts of the left ventricles were evaluated. Hypoxia inducible factor-1 (HIF-1), vascular endothelial growth factor 164 (VEGF164), and VEGF188 polymerase chain reaction products were run in agarose gel electrophoresis. Band density analysis of UV camera images was performed using Image J. The data were compared by one-way ANOVA, repeated measures two-way ANOVA, and the Kruskal-Wallis test. RESULTS The percent weight change was lower in the DM group than in the controls (p=0.004). The tissue injury was the highest in the DM group and the least in the IH group. Diabetes decreased, whereas the IH treatment increased the vascularity. A decrease was observed in the VEGF188 mRNA levels in the DM+IH group compared with the C group, but there were no difference in HIF-1α and VEGF164 mRNA levels between the groups. CONCLUSION The IH treatment restored the diabetic effects on the heart by reducing tissue injury and increasing the capillarity without transcriptional changes in HIF-1/VEGF correspondingly.
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Affiliation(s)
- Derya Güzel
- Department of Physiology, Faculty of Medicine, Sakarya University; Sakarya-Turkey.
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Samaja M, Milano G. Editorial - Hypoxia and Reoxygenation: From Basic Science to Bedside. Front Pediatr 2015; 3:86. [PMID: 26539421 PMCID: PMC4609843 DOI: 10.3389/fped.2015.00086] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Accepted: 09/30/2015] [Indexed: 12/30/2022] Open
Affiliation(s)
- Michele Samaja
- Department of Health Science, University of Milan , Milan , Italy
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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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Hypoxia training attenuates left ventricular remodeling in rabbit with myocardial infarction. JOURNAL OF GERIATRIC CARDIOLOGY : JGC 2014; 11:237-44. [PMID: 25278973 PMCID: PMC4178516 DOI: 10.11909/j.issn.1671-5411.2014.03.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 05/12/2014] [Accepted: 06/10/2014] [Indexed: 11/21/2022]
Abstract
Objective Previous studies showed that hypoxia preconditioning could protect cardiac function against subsequent myocardial infarction injury. However, the effect of hypoxia on left ventricular after myocardial infarction is still unclear. This study therefore aims to investigate the effects of hypoxia training on left ventricular remodeling in rabbits post myocardial infarction. Methods Adult male rabbits were randomly divided into three groups: group SO (sham operated), group MI (myocardial infarction only) and group MI-HT (myocardial infarction plus hypoxia training). Myocardial infarction was induced by left ventricular branch ligation. Hypoxia training was performed in a hypobaric chamber (having equivalent condition at an altitude of 4000 m, FiO214.9%) for 1 h/day, 5 days/week for four weeks. At the endpoints, vascular endothelial growth factor (VEGF) in the plasma was measured. Infarct size and capillary density were detected by histology. Left ventricular remodeling and function were assessed by echocardiography. Results After the 4-week experiment, compared with the group SO, plasma VEGF levels in groups MI (130.27 ± 18.58 pg/mL, P < 0.01) and MI-HT (181.93 ± 20.29 pg/mL, P < 0.01) were significantly increased. Infarct size in Group MI-HT (29.67% ± 7.73%) was deceased remarkably, while its capillary density (816.0 ± 122.2/mm2) was significantly increased. For both groups MI and MI-HT, left ventricular end-diastolic and end-systolic dimensions were increased whereas left ventricular ejection fraction was decreased. However, compared with group MI, group MI-HT diminished left ventricular end-diastolic (15.86 ± 1.09 mm, P < 0.05) and end-systolic dimensions (12.10 ± 1.20 mm, P < 0.01) significantly and improved left ventricular ejection fraction (54.39 ± 12.74 mm, P < 0.05). Conclusion Hypoxia training may improve left ventricular function and reduce remodeling via angiogenesis in rabbits with MI.
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Cohen JE, Purcell BP, MacArthur JW, Mu A, Shudo Y, Patel JB, Brusalis CM, Trubelja A, Fairman AS, Edwards BB, Davis MS, Hung G, Hiesinger W, Atluri P, Margulies KB, Burdick JA, Woo YJ. A bioengineered hydrogel system enables targeted and sustained intramyocardial delivery of neuregulin, activating the cardiomyocyte cell cycle and enhancing ventricular function in a murine model of ischemic cardiomyopathy. Circ Heart Fail 2014; 7:619-26. [PMID: 24902740 DOI: 10.1161/circheartfailure.113.001273] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
BACKGROUND Neuregulin-1β (NRG) is a member of the epidermal growth factor family possessing a critical role in cardiomyocyte development and proliferation. Systemic administration of NRG demonstrated efficacy in cardiomyopathy animal models, leading to clinical trials using daily NRG infusions. This approach is hindered by requiring daily infusions and off-target exposure. Therefore, this study aimed to encapsulate NRG in a hydrogel to be directly delivered to the myocardium, accomplishing sustained localized NRG delivery. METHODS AND RESULTS NRG was encapsulated in hydrogel, and release over 14 days was confirmed by ELISA in vitro. Sprague-Dawley rats were used for cardiomyocyte isolation. Cells were stimulated by PBS, NRG, hydrogel, or NRG-hydrogel (NRG-HG) and evaluated for proliferation. Cardiomyocytes demonstrated EdU (5-ethynyl-2'-deoxyuridine) and phosphorylated histone H3 positivity in the NRG-HG group only. For in vivo studies, 2-month-old mice (n=60) underwent left anterior descending coronary artery ligation and were randomized to the 4 treatment groups mentioned. Only NRG-HG-treated mice demonstrated phosphorylated histone H3 and Ki67 positivity along with decreased caspase-3 activity compared with all controls. NRG was detected in myocardium 6 days after injection without evidence of off-target exposure in NRG-HG animals. At 2 weeks, the NRG-HG group exhibited enhanced left ventricular ejection fraction, decreased left ventricular area, and augmented borderzone thickness. CONCLUSIONS Targeted and sustained delivery of NRG directly to the myocardial borderzone augments cardiomyocyte mitotic activity, decreases apoptosis, and greatly enhances left ventricular function in a model of ischemic cardiomyopathy. This novel approach to NRG administration avoids off-target exposure and represents a clinically translatable strategy in myocardial regenerative therapeutics.
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Affiliation(s)
- Jeffrey E Cohen
- From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia
| | - Brendan P Purcell
- From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia
| | - John W MacArthur
- From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia
| | - Anbin Mu
- From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia
| | - Yasuhiro Shudo
- From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia
| | - Jay B Patel
- From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia
| | - Christopher M Brusalis
- From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia
| | - Alen Trubelja
- From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia
| | - Alexander S Fairman
- From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia
| | - Bryan B Edwards
- From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia
| | - Mollie S Davis
- From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia
| | - George Hung
- From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia
| | - William Hiesinger
- From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia
| | - Pavan Atluri
- From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia
| | - Kenneth B Margulies
- From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia
| | - Jason A Burdick
- From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia
| | - Y Joseph Woo
- From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia.
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Jackman KA, Zhou P, Faraco G, Peixoto PM, Coleman C, Voss HU, Pickel V, Manfredi G, Iadecola C. Dichotomous effects of chronic intermittent hypoxia on focal cerebral ischemic injury. Stroke 2014; 45:1460-7. [PMID: 24713530 DOI: 10.1161/strokeaha.114.004816] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
BACKGROUND AND PURPOSE Obstructive sleep apnea, a condition associated with chronic intermittent hypoxia (CIH), carries an increased risk of stroke. However, CIH has been reported to either increase or decrease brain injury in models of focal cerebral ischemia. The factors determining the differential effects of CIH on ischemic injury and their mechanisms remain unclear. Here, we tested the hypothesis that the intensity of the hypoxic challenge determines the protective or destructive nature of CIH by modulating mitochondrial resistance to injury. METHODS Male C57Bl/6J mice were exposed to CIH with 10% or 6% O2 for ≤35 days and subjected to transient middle cerebral artery occlusion. Motor deficits and infarct volume were assessed 3 days later. Intraischemic cerebral blood flow was measured by laser-Doppler flowmetry and resting cerebral blood flow by arterial spin labeling MRI. Ca2+-induced mitochondrial depolarization and reactive oxygen species production were evaluated in isolated brain mitochondria. RESULTS We found that 10% CIH is neuroprotective, whereas 6% CIH exacerbates tissue damage. No differences in resting or intraischemic cerebral blood flow were observed between 6% and 10% CIH. However, 10% CIH reduced, whereas 6% CIH increased, mitochondrial reactive oxygen species production and susceptibility to Ca2+-induced depolarizations. CONCLUSIONS The influence of CIH on the ischemic brain is dichotomous and can be attributed, in part, to changes in the mitochondrial susceptibility to injury. The findings highlight a previously unappreciated complexity in the effect of CIH on the brain, which needs to be considered in evaluating the neurological effect of conditions associated with cyclic hypoxia.
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Affiliation(s)
- Katherine A Jackman
- From the Feil Family Brain and Mind Research Institute (K.A.J., P.Z., G.F., P.M.P., C.C., V.P., G.M., C.I.) and Department of Radiology (H.U.V.), Weill Cornell Medical College, New York; and Department of Natural Sciences, Baruch College, City University of New York (P.M.P.)
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