1
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Abdel-Hady EA. Chromium picolinate supplementation improves cardiac performance in hypoxic rats. Acta Cardiol 2024; 79:387-397. [PMID: 36044000 DOI: 10.1080/00015385.2022.2041782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 12/02/2021] [Accepted: 02/09/2022] [Indexed: 11/01/2022]
Abstract
BACKGROUND Conditions associated with chronic hypoxia increase morbidity and mortality attributable to cardiovascular complications. Myocardial hypoxia is a common feature in several diseases including: stroke, infarction, anaemia, chronic lung diseases, obstructive sleep apnoea and cyanotic congenital heart defects. The present study was planned to investigate the cardiovascular effects of chronic intermittent hypoxia and its association with increased myocardial oxidative stress. In addition, to evaluate the protective effect of chromium supplementation, aiming at achieving an alternative that may enable to devise a therapy for hypoxic patients. METHODS Male rats were allocated into three groups: control group (normoxic), untreated hypoxic group (exposed to hypoxia 8 h/day, 5 days/week for 6 weeks) and hypoxic group supplemented with chromium picolinate (90 µg/kg/day by gavage). Rats were subjected to measurement of body weight, haematocrit value, mean arterial blood pressure, heart rate and ECG recording. Cardiac activities of isolated hearts were studied on Langendorff preparation under basal conditions and in response to ischaemia/reperfusion. Thereafter, cardiac weights were determined and cardiac tissue catalase activity as well as malondialdhyde level were assessed. RESULTS Significant results were obtained upon exposure to hypoxia including; low body weight, increased haematocrit, elevated blood pressure, left ventricular hypertrophy and impaired cardiac activities, basally and in response to ischaemia/reperfusion challenges, associated with increased oxidative stress in cardiac tissue. At the same time, chromium supplementation increased body weight, lowered blood pressure, reduced ventricular hypertrophy and significantly improved the cardiac performance. CONCLUSION Chromium supplementation confers protection against hypoxia-induced cardiovascular dysfunction by improvement of the antioxidant capacity.
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Affiliation(s)
- Enas A Abdel-Hady
- Physiology Department, Faculty of Medicine, Ain Shams University, Cairo, Egypt
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2
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Supriya R, Gao Y, Gu Y, Baker JS. Role of Exercise Intensity on Th1/Th2 Immune Modulations During the COVID-19 Pandemic. Front Immunol 2021; 12:761382. [PMID: 35003073 PMCID: PMC8727446 DOI: 10.3389/fimmu.2021.761382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 12/07/2021] [Indexed: 12/02/2022] Open
Abstract
The COVID-19 pandemic has led to several pioneering scientific discoveries resulting in no effective solutions with the exception of vaccination. Moderate exercise is a significant non-pharmacological strategy, to reduce the infection-related burden of COVID-19, especially in patients who are obese, elderly, and with additional comorbidities. The imbalance of T helper type 1 (Th1) or T helper type 2 (Th2) cells has been well documented among populations who have suffered as a result of the COVID-19 pandemic, and who are at maximum risk of infection and mortality. Moderate and low intensity exercise can benefit persons at risk from the disease and survivors by favorable modulation in Th1/Th2 ratios. Moreover, in COVID-19 patients, mild to moderate intensity aerobic exercise also increases immune system function but high intensity aerobic exercise may have adverse effects on immune responses. In addition, sustained hypoxia in COVID-19 patients has been reported to cause organ failure and cell death. Hypoxic conditions have also been highlighted to be triggered in COVID-19-susceptible individuals and COVID-19 survivors. This suggests that hypoxia inducible factor (HIF 1α) might be an important focus for researchers investigating effective strategies to minimize the effects of the pandemic. Intermittent hypoxic preconditioning (IHP) is a method of exposing subjects to short bouts of moderate hypoxia interspersed with brief periods of normal oxygen concentrations (recovery). This methodology inhibits the production of pro-inflammatory factors, activates HIF-1α to activate target genes, and subsequently leads to a higher production of red blood cells and hemoglobin. This increases angiogenesis and increases oxygen transport capacity. These factors can help alleviate virus induced cardiopulmonary hemodynamic disorders and endothelial dysfunction. Therefore, during the COVID-19 pandemic we propose that populations should engage in low to moderate exercise individually designed, prescribed and specific, that utilizes IHP including pranayama (yoga), swimming and high-altitude hiking exercise. This would be beneficial in affecting HIF-1α to combat the disease and its severity. Therefore, the promotion of certain exercises should be considered by all sections of the population. However, exercise recommendations and prescription for COVID-19 patients should be structured to match individual levels of capability and adaptability.
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Affiliation(s)
- Rashmi Supriya
- Faculty of Sports Science, Ningbo University, Zhejiang, China
- Centre for Health and Exercise Science Research, Department of Sport, Physical Education and Health, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR, China
- *Correspondence: Rashmi Supriya,
| | - Yang Gao
- Faculty of Sports Science, Ningbo University, Zhejiang, China
- Centre for Health and Exercise Science Research, Department of Sport, Physical Education and Health, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR, China
| | - Yaodong Gu
- Faculty of Sports Science, Ningbo University, Zhejiang, China
- Centre for Health and Exercise Science Research, Department of Sport, Physical Education and Health, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR, China
| | - Julien S. Baker
- Faculty of Sports Science, Ningbo University, Zhejiang, China
- Centre for Health and Exercise Science Research, Department of Sport, Physical Education and Health, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR, China
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3
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Chacon-Barahona JA, Salladay-Perez IA, Lanning NJ. Lung Adenocarcinoma Transcriptomic Analysis Predicts Adenylate Kinase Signatures Contributing to Tumor Progression and Negative Patient Prognosis. Metabolites 2021; 11:metabo11120859. [PMID: 34940617 PMCID: PMC8705281 DOI: 10.3390/metabo11120859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 11/30/2021] [Indexed: 11/16/2022] Open
Abstract
The ability to detect and respond to hypoxia within a developing tumor appears to be a common feature amongst most cancers. This hypoxic response has many molecular drivers, but none as widely studied as Hypoxia-Inducible Factor 1 (HIF-1). Recent evidence suggests that HIF-1 biology within lung adenocarcinoma (LUAD) may be associated with expression levels of adenylate kinases (AKs). Using LUAD patient transcriptome data, we sought to characterize AK gene signatures related to lung cancer hallmarks, such as hypoxia and metabolic reprogramming, to identify conserved biological themes across LUAD tumor progression. Transcriptomic analysis revealed perturbation of HIF-1 targets to correlate with altered expression of most AKs, with AK4 having the strongest correlation. Enrichment analysis of LUAD tumor AK4 gene signatures predicts signatures involved in pyrimidine, and by extension, nucleotide metabolism across all LUAD tumor stages. To further discriminate potential drivers of LUAD tumor progression within AK4 gene signatures, partial least squares discriminant analysis was used at LUAD stage-stage interfaces, identifying candidate genes that may promote LUAD tumor growth or regression. Collectively, these results characterize regulatory gene networks associated with the expression of all nine human AKs that may contribute to underlying metabolic perturbations within LUAD and reveal potential mechanistic insight into the complementary role of AK4 in LUAD tumor development.
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Affiliation(s)
- Jonathan A. Chacon-Barahona
- Department of Biological Sciences, California State University, Los Angeles, CA 90032, USA; (J.A.C.-B.); (I.A.S.-P.)
| | - Ivan A. Salladay-Perez
- Department of Biological Sciences, California State University, Los Angeles, CA 90032, USA; (J.A.C.-B.); (I.A.S.-P.)
- Molecular Biology Interdepartmental Program, University of California, Los Angeles, CA 94701, USA
| | - Nathan James Lanning
- Department of Biological Sciences, California State University, Los Angeles, CA 90032, USA; (J.A.C.-B.); (I.A.S.-P.)
- Correspondence: ; Tel.: +1-(323)-343-2092
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4
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Chen L, Shi D, Guo M. The roles of PKC-δ and PKC-ε in myocardial ischemia/reperfusion injury. Pharmacol Res 2021; 170:105716. [PMID: 34102229 DOI: 10.1016/j.phrs.2021.105716] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 05/01/2021] [Accepted: 06/03/2021] [Indexed: 01/14/2023]
Abstract
Ischemia and reperfusion (I/R) cause a reduction in arterial blood supply to tissues, followed by the restoration of perfusion and consequent reoxygenation. The reestablishment of blood flow triggers further damage to ischemic tissue through reactive oxygen species (ROS) accumulation, interference with cellular ion homeostasis, opening of mitochondrial permeability transition pores (mPTPs) and promotion of cell death (apoptosis or necrosis). PKC-δ and PKC-ε, belonging to a family of serine/threonine kinases, have been demonstrated to play important roles during I/R injury in cardiovascular diseases. However, the cardioprotective mechanisms of PKC-δ and PKC-ε in I/R injury have not been elaborated until now. This article discusses the roles of PKC-δ and PKC-ε during myocardial I/R in redox regulation (redox signaling and oxidative stress), cell death (apoptosis and necrosis), Ca2+ overload, and mitochondrial dysfunction.
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Affiliation(s)
- Li Chen
- Peking University Traditional Chinese Medicine Clinical Medical School (Xi yuan), Beijing, China; National Clinical Research Center for Chinese Medicine Cardiology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Dazhuo Shi
- National Clinical Research Center for Chinese Medicine Cardiology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China.
| | - Ming Guo
- National Clinical Research Center for Chinese Medicine Cardiology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China.
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5
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Cai M, Chen X, Shan J, Yang R, Guo Q, Bi X, Xu P, Shi X, Chu L, Wang L. Intermittent Hypoxic Preconditioning: A Potential New Powerful Strategy for COVID-19 Rehabilitation. Front Pharmacol 2021; 12:643619. [PMID: 33995053 PMCID: PMC8120309 DOI: 10.3389/fphar.2021.643619] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 03/15/2021] [Indexed: 01/08/2023] Open
Abstract
COVID-19 is a highly infectious respiratory virus, which can proliferate by invading the ACE2 receptor of host cells. Clinical studies have found that the virus can cause dyspnea, pneumonia and other cardiopulmonary system damage. In severe cases, it can lead to respiratory failure and even death. Although there are currently no effective drugs or vaccines for the prevention and treatment of COVID-19, the patient’s prognosis recovery can be effectively improved by ameliorating the dysfunction of the respiratory system, cardiovascular systems, and immune function. Intermittent hypoxic preconditioning (IHP) as a new non-drug treatment has been applied in the clinical and rehabilitative practice for treating chronic obstructive pulmonary disease (COPD), diabetes, coronary heart disease, heart failure, hypertension, and other diseases. Many clinical studies have confirmed that IHP can improve the cardiopulmonary function of patients and increase the cardiorespiratory fitness and the tolerance of tissues and organs to ischemia. This article introduces the physiological and biochemical functions of IHP and proposes the potential application plan of IHP for the rehabilitation of patients with COVID-19, so as to provide a better prognosis for patients and speed up the recovery of the disease. The aim of this narrative review is to propose possible causes and pathophysiology of COVID-19 based on the mechanisms of the oxidative stress, inflammation, and immune response, and to provide a new, safe and efficacious strategy for the better rehabilitation from COVID-19.
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Affiliation(s)
- Ming Cai
- Shanghai University of Medicine and Health Sciences Affiliated Zhoupu Hospital, Shanghai, China
| | - Xuan Chen
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
| | - Jieling Shan
- Department of Ultrasound, Huashan Hospital, Fudan University, Shanghai, China
| | - Ruoyu Yang
- College of Rehabilitation Science, Shanghai University of Medicine and Health Sciences, Shanghai, China
| | - Qi Guo
- Shanghai University of Medicine and Health Sciences Affiliated Zhoupu Hospital, Shanghai, China
| | - Xia Bi
- Shanghai University of Medicine and Health Sciences Affiliated Zhoupu Hospital, Shanghai, China
| | - Ping Xu
- College of Rehabilitation Science, Shanghai University of Medicine and Health Sciences, Shanghai, China
| | - Xiangrong Shi
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, United States
| | - Lixi Chu
- College of Rehabilitation Science, Shanghai University of Medicine and Health Sciences, Shanghai, China.,Shanghai Sunshine Rehabilitation Center, Shanghai, China
| | - Liyan Wang
- College of Rehabilitation Science, Shanghai University of Medicine and Health Sciences, Shanghai, China
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6
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Shi ZJ, Cheng M, Liu YC, Fan XR, Zhang Y, Wei Y. Effect of chronic intermittent hypobaric hypoxia on heart rate variability in conscious rats. Clin Exp Pharmacol Physiol 2019; 47:60-66. [PMID: 31454428 DOI: 10.1111/1440-1681.13170] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 08/22/2019] [Indexed: 01/09/2023]
Abstract
To examine the effect of chronic intermittent hypobaric hypoxia (CIHH) on heart rate variability (HRV), male adult Sprague Dawley rats were exposed to hypoxia (oxygen 11.1%) in a hypobaric chamber for 42 days, 6 hours each day, simulating an altitude of 5000 m. The body weight and blood pressure of rats were recorded once a week, electrocardiograms were analyzed continuously using biotelemetry, before, during and after CIHH treatment each day, and HRV was evaluated using spectrum analysis. No significant difference of body weight and blood pressure was found between CIHH and control rats. After 4 weeks of CIHH treatment, total power (TP) and very low-frequency component (VLF) were lower in CIHH rats than in control rats under hypobaric hypoxia condition. During CIHH treatment, low frequency (LF) was higher in 1 week and lower in 5-6 weeks in CIHH rats than control rats under hypobaric hypoxia, but not normoxic conditions. The high-frequency component (HF) was not changed during CIHH treatment, so LF/HF increased initially, and then recovered under the hypobaric hypoxia condition following 3 weeks of CIHH treatment. In addition, the HR was increased in CIHH rats after 4 weeks of CIHH treatment compared with control rats. Furthermore, HRV was altered significantly in control rats, but not in CIHH rats exposed to acute normobaric hypoxia. These data suggest that CIHH treatment modulates cardiac autonomic activity adaptively and inhibits the acute normobaric hypoxia-induced changes in HRV.
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Affiliation(s)
- Zhang-Jing Shi
- Department of Cardiology, The First Affiliated Hospital of Southwest Medical University, Luzhou, China.,Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Ming Cheng
- Aerospace Center Hospital, Beijing, China
| | - Ying-Cai Liu
- Department of Cardiology, The First Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Xin-Rong Fan
- Department of Cardiology, The First Affiliated Hospital of Southwest Medical University, Luzhou, China.,Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Yi Zhang
- Department of Physiology, Hebei Medical University, Shijiazhuang, China
| | - Yan Wei
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China.,Department of Physiology, Hebei Medical University, Shijiazhuang, China
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7
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Chang JC, Lien CF, Lee WS, Chang HR, Hsu YC, Luo YP, Jeng JR, Hsieh JC, Yang KT. Intermittent Hypoxia Prevents Myocardial Mitochondrial Ca 2+ Overload and Cell Death during Ischemia/Reperfusion: The Role of Reactive Oxygen Species. Cells 2019; 8:cells8060564. [PMID: 31181855 PMCID: PMC6627395 DOI: 10.3390/cells8060564] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 06/01/2019] [Accepted: 06/05/2019] [Indexed: 12/24/2022] Open
Abstract
It has been documented that reactive oxygen species (ROS) contribute to oxidative stress, leading to diseases such as ischemic heart disease. Recently, increasing evidence has indicated that short-term intermittent hypoxia (IH), similar to ischemia preconditioning, could yield cardioprotection. However, the underlying mechanism for the IH-induced cardioprotective effect remains unclear. The aim of this study was to determine whether IH exposure can enhance antioxidant capacity, which contributes to cardioprotection against oxidative stress and ischemia/reperfusion (I/R) injury in cardiomyocytes. Primary rat neonatal cardiomyocytes were cultured in IH condition with an oscillating O2 concentration between 20% and 5% every 30 min. An MTT assay was conducted to examine the cell viability. Annexin V-FITC and SYTOX green fluorescent intensity and caspase 3 activity were detected to analyze the cell death. Fluorescent images for DCFDA, Fura-2, Rhod-2, and TMRM were acquired to analyze the ROS, cytosol Ca2+, mitochondrial Ca2+, and mitochondrial membrane potential, respectively. RT-PCR, immunocytofluorescence staining, and antioxidant activity assay were conducted to detect the expression of antioxidant enzymes. Our results show that IH induced slight increases of O2−· and protected cardiomyocytes against H2O2- and I/R-induced cell death. Moreover, H2O2-induced Ca2+ imbalance and mitochondrial membrane depolarization were attenuated by IH, which also reduced the I/R-induced Ca2+ overload. Furthermore, treatment with IH increased the expression of Cu/Zn SOD and Mn SOD, the total antioxidant capacity, and the activity of catalase. Blockade of the IH-increased ROS production abolished the protective effects of IH on the Ca2+ homeostasis and antioxidant defense capacity. Taken together, our findings suggest that IH protected the cardiomyocytes against H2O2- and I/R-induced oxidative stress and cell death through maintaining Ca2+ homeostasis as well as the mitochondrial membrane potential, and upregulation of antioxidant enzymes.
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Affiliation(s)
- Jui-Chih Chang
- Department of Surgery, Buddhist Tzu Chi General Hospital, Hualien 97002, Taiwan.
- School of Medicine, Tzu Chi University, Hualien 97004, Taiwan.
| | - Chih-Feng Lien
- Institute of Medical Sciences, Tzu Chi University, Hualien 97004, Taiwan.
| | - Wen-Sen Lee
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.
| | - Huai-Ren Chang
- School of Medicine, Tzu Chi University, Hualien 97004, Taiwan.
- Division of Cardiology, Department of Internal Medicine, Buddhist Tzu Chi General Hospital, Hualien 97002, Taiwan.
| | - Yu-Cheng Hsu
- Master Program in Medical Physiology, School of Medicine, Tzu Chi University, Hualien 97004, Taiwan.
| | - Yu-Po Luo
- Department of Surgery, Buddhist Tzu Chi General Hospital, Hualien 97002, Taiwan.
| | - Jing-Ren Jeng
- School of Medicine, Tzu Chi University, Hualien 97004, Taiwan.
- Division of Cardiology, Department of Internal Medicine, Buddhist Tzu Chi General Hospital, Hualien 97002, Taiwan.
| | - Jen-Che Hsieh
- School of Medicine, Tzu Chi University, Hualien 97004, Taiwan.
- Division of Cardiology, Department of Internal Medicine, Buddhist Tzu Chi General Hospital, Hualien 97002, Taiwan.
| | - Kun-Ta Yang
- Department of Physiology, School of Medicine, Tzu Chi University, Hualien 97004, Taiwan.
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8
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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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9
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Bu HM, Yang CY, Wang ML, Ma HJ, Sun H, Zhang Y. K(ATP) channels and MPTP are involved in the cardioprotection bestowed by chronic intermittent hypobaric hypoxia in the developing rat. J Physiol Sci 2015; 65:367-76. [PMID: 25862574 PMCID: PMC10717084 DOI: 10.1007/s12576-015-0376-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 03/18/2015] [Indexed: 10/23/2022]
Abstract
The aim of this study was to explore the mechanism underlying the cardioprotection bestowed by chronic intermittent hypobaric hypoxia (CIHH) against ischemia/reperfusion (I/R) injury in developing rats. Neonatal male rats were subjected to CIHH treatments that simulated an altitude of 3000 m a.s.l. for 28 days (CIHH28) and 42 days (CIHH42), respectively, or no treatment (control). The left ventricular function of isolated hearts was evaluated. The ultra-microstructure, superoxide dismutase (SOD) activity and total anti-oxidation capacity (TAC) of the myocardium were determined. The basic left ventricular function remained unchanged in CIHH rats, except for an increased coronary flow. The recovery of cardiac function from I/R, however, was much better in CIHH rats than in control rats. Compared to control rats, CIHH rats had much higher SOD levels and TAC, and the ultra-microstructure damage to mitochondria was considerably less. The cardiac protection of CIHH was canceled out by glibenclamide, an inhibitor of the ATP-sensitive potassium (K(ATP)) channel, 5-hydroxydecanoate, an inhibitor of mitochondrial K(ATP) (mitoKATP), and atractyloside, an opener of the mitochondrial permeability transition pore (MPTP). To the contrary, diazoxide, an opener of mitoKATP, and cyclosporin A, a blocker of MPTP opening, induced cardioprotection in control rats. These results suggest that CIHH protects the heart against I/R injury in developing rats through opening of the K(ATP) channel and inhibiting of opening of the MPTP.
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Affiliation(s)
- Hui-min Bu
- Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 China
- Department of Physiology, Xuzhou Medical College, Xuzhou, 221004 China
| | - Chang-ying Yang
- Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 China
| | - Mei-ling Wang
- Electrophysiological Department, Central Hospital of Cangzhou, Cangzhou, 061001 China
| | - Hui-jie Ma
- Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 China
- Hebei Collaborative Innovation Center for Cardio-cerebrovascular Disease, Shijiazhuang, 050000 China
| | - Hong Sun
- Department of Physiology, Xuzhou Medical College, Xuzhou, 221004 China
| | - Yi Zhang
- Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 China
- Hebei Collaborative Innovation Center for Cardio-cerebrovascular Disease, Shijiazhuang, 050000 China
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10
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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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11
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Herrera EA, Farías JG, González-Candia A, Short SE, Carrasco-Pozo C, Castillo RL. Ω3 Supplementation and intermittent hypobaric hypoxia induce cardioprotection enhancing antioxidant mechanisms in adult rats. Mar Drugs 2015; 13:838-60. [PMID: 25658050 PMCID: PMC4344605 DOI: 10.3390/md13020838] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 01/13/2015] [Accepted: 01/16/2015] [Indexed: 01/29/2023] Open
Abstract
Intermittent hypobaric hypoxia (IH) is linked with oxidative stress, impairing cardiac function. However, early IH also activate cardio-protective mechanisms. Omega 3 fatty acids (Ω3) induce cardioprotection by reducing infarct size and reinforcing antioxidant defenses. The aim of this work was to determine the combined effects of IH and Ω3 on cardiac function; oxidative balance and inflammatory state. Twenty-eight rats were randomly divided into four groups: normobaric normoxia (N); N + Ω3 (0.3 g·kg−1·day−1); IH; and IH + Ω3. IH was induced by 4 intercalate periods of hypoxia (4 days)—normoxia (4 days) in a hypobaric chamber during 32 days. At the end of the exposure, hearts were mounted in a Langendorff system and subjected to 30 min of ischemia followed by 120 min of reperfusion. In addition, we determined HIF-1α and ATP levels, as well as oxidative stress by malondialdehyde and nitrotyrosine quantification. Further, the expression of the antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase was determined. NF-kappaB and myeloperoxidase levels were assessed in the hearts. Relative to N hearts, IH improved left ventricular function (Left ventricular developed pressure: N; 21.8 ± 3.4 vs. IH; 42.8 ± 7.1 mmHg; p < 0.05); reduced oxidative stress (Malondialdehyde: N; 14.4 ± 1.8 vs. IH; 7.3 ± 2.1 μmol/mg prot.; p < 0.05); and increased antioxidant enzymes expression. Supplementation with Ω3 induces similar responses as IH group. Our findings suggest that both, IH and Ω3 in an independent manner, induce functional improvement by antioxidant and anti-inflammatory mechanisms, establishing cardio-protection.
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Affiliation(s)
- Emilio A Herrera
- Programa de Fisiopatología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile.
| | - Jorge G Farías
- Departamento de Ingeniería Química, Facultad de Ingeniería y Ciencias, Universidad de la Frontera, Temuco 4811230, Chile.
| | - Alejandro González-Candia
- Programa de Fisiopatología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile.
| | - Stefania E Short
- Departamento de Ingeniería Química, Facultad de Ingeniería y Ciencias, Universidad de la Frontera, Temuco 4811230, Chile.
| | - Catalina Carrasco-Pozo
- Departamento de Nutrición, Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile.
| | - Rodrigo L Castillo
- Programa de Fisiopatología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile.
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12
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Li R, Luo X, Wu J, Thangthaeng N, Jung ME, Jing S, Li L, Ellis DZ, Liu L, Ding Z, Forster MJ, Yan LJ. Mitochondrial Dihydrolipoamide Dehydrogenase is Upregulated in Response to Intermittent Hypoxic Preconditioning. Int J Med Sci 2015; 12:432-40. [PMID: 26078703 PMCID: PMC4466405 DOI: 10.7150/ijms.11402] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Accepted: 05/13/2015] [Indexed: 01/06/2023] Open
Abstract
Intermittent hypoxia preconditioning (IHP) has been shown to protect neurons against ischemic stroke injury. Studying how proteins respond to IHP may identify targets that can help fight stroke. The objective of the present study was to investigate whether mitochondrial dihydrolipoamide dehydrogenase (DLDH) would respond to IHP and if so, whether such a response could be linked to neuroprotection in ischemic stroke injury. To do this, we subjected male rats to IHP for 20 days and measured the content and activity of DLDH as well as the three α-keto acid dehydrogenase complexes that contain DLDH. We also measured mitochondrial electron transport chain enzyme activities. Results show that DLDH content was indeed upregulated by IHP and this upregulation did not alter the activities of the three α-keto acid dehydrogenase complexes. Results also show that the activities of the five mitochondrial complexes (I-V) were not altered either by IHP. To investigate whether IHP-induced DLDH upregulation is linked to neuroprotection against ischemic stroke injury, we subjected both DLDH deficient mouse and DLDH transgenic mouse to stroke surgery followed by measurement of brain infarction volume. Results indicate that while mouse deficient in DLDH had exacerbated brain injury after stroke, mouse overexpressing human DLDH also showed increased brain injury after stroke. Therefore, the physiological significance of IHP-induced DLDH upregulation remains to be further investigated.
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Affiliation(s)
- Rongrong Li
- 1. Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA ; 2. Department of Anethesiology, the First Affiliated Hospital of Nanjing University, Nanjing, Jiangsu province, China, 210029
| | - Xiaoting Luo
- 1. Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA ; 3. Department of Biochemistry and Molecular Biology, Gannan Medical University, Ganzhou, Jiangxi province, China, 341000
| | - Jinzi Wu
- 1. Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Nopporn Thangthaeng
- 4. Department of Pharmacology and Neurosciences, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Marianna E Jung
- 4. Department of Pharmacology and Neurosciences, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Siqun Jing
- 1. Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA ; 5. College of Life Sciences and Technology, Xinjiang University, Urumqi, Xinjiang, China, 830046
| | - Linya Li
- 1. Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Dorette Z Ellis
- 1. Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Li Liu
- 6. Department of Geriatrics, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China 210029
| | - Zhengnian Ding
- 2. Department of Anethesiology, the First Affiliated Hospital of Nanjing University, Nanjing, Jiangsu province, China, 210029
| | - Michael J Forster
- 4. Department of Pharmacology and Neurosciences, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Liang-Jun Yan
- 1. Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
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13
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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: 281] [Impact Index Per Article: 28.1] [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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14
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Mapanga RF, Joseph D, Symington B, Garson KL, Kimar C, Kelly-Laubscher R, Essop M. Detrimental effects of acute hyperglycaemia on the rat heart. Acta Physiol (Oxf) 2014; 210:546-64. [PMID: 24286628 DOI: 10.1111/apha.12184] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 08/27/2013] [Accepted: 10/19/2013] [Indexed: 01/08/2023]
Abstract
AIM Hyperglycaemia is an important risk factor for acute myocardial infarction. It can lead to increased induction of non-oxidative glucose pathways (NOGPs) - polyol and hexosamine biosynthetic pathways, advanced glycation end products and protein kinase C - that may contribute to cardiovascular diseases onset. However, the precise underlying mechanisms remain poorly understood. Here we hypothesized that acute hyperglycaemia increases myocardial oxidative stress and NOGP activation resulting in cardiac dysfunction during ischaemia-reperfusion and that inhibition of, and/or shunting flux away from NOGPs [by benfotiamine (BFT) treatment], leads to cardioprotection. METHODS We employed several experimental systems: (i) Isolated rat hearts were perfused ex vivo with Krebs-Henseleit buffer containing 33 mm glucose vs. controls (11 mm glucose) ± global ischaemia and reperfusion ± BFT (first 20 min of reperfusion); (ii) Infarct size determination as per the ischaemic protocol, but with regional ischaemia and reperfusion ± BFT treatment; in separate experiments, NOGP inhibitors were also employed for (i) and (ii); and (iii) In vivo coronary ligations performed on streptozotocin-treated rats ± BFT treatment (early reperfusion). RESULTS Acute hyperglycaemia generated myocardial oxidative stress, NOGP activation and apoptosis, but caused no impairment of cardiac function during pre-ischaemia, thereby priming hearts for later damage. Following ischaemia-reperfusion (under hyperglycaemic conditions), such effects were exacerbated together with cardiac contractile dysfunction. Moreover, inhibition of respective NOGPs and shunting away by BFT treatment (in part) improved cardiac function during ischaemia-reperfusion. CONCLUSION Coordinate NOGP activation in response to acute hyperglycaemia results in contractile dysfunction during ischaemia-reperfusion, allowing for the development of novel cardioprotective agents.
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Affiliation(s)
- R. F. Mapanga
- Cardio-Metabolic Research Group (CMRG); Department of Physiological Sciences; Stellenbosch University; Stellenbosch South Africa
| | - D. Joseph
- Cardio-Metabolic Research Group (CMRG); Department of Physiological Sciences; Stellenbosch University; Stellenbosch South Africa
| | - B. Symington
- Cardio-Metabolic Research Group (CMRG); Department of Physiological Sciences; Stellenbosch University; Stellenbosch South Africa
| | - K.-L. Garson
- Cardio-Metabolic Research Group (CMRG); Department of Physiological Sciences; Stellenbosch University; Stellenbosch South Africa
| | - C. Kimar
- Cardio-Metabolic Research Group (CMRG); Department of Physiological Sciences; Stellenbosch University; Stellenbosch South Africa
| | - R. Kelly-Laubscher
- Department of Human Biology; Faculty of Health Sciences; University of Cape Town; Observatory South Africa
| | - M.Faadiel Essop
- Cardio-Metabolic Research Group (CMRG); Department of Physiological Sciences; Stellenbosch University; Stellenbosch South Africa
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15
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Wang Z, Si LY. Hypoxia-inducible factor-1α and vascular endothelial growth factor in the cardioprotective effects of intermittent hypoxia in rats. Ups J Med Sci 2013; 118:65-74. [PMID: 23441597 PMCID: PMC3633332 DOI: 10.3109/03009734.2013.766914] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 12/11/2012] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVE This study investigated the effects of short-term intermittent hypoxia (IH) preconditioning on cardiac structure and function in rats and the influence of ischemia reperfusion (I/R) injury. Special attention was then paid to the involvement of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF). METHODS Wistar rats were given IH treatment for 1, 7, 14, or 28 days. Some of them were thereafter subject to myocardial infarction surgery. Right ventricle systolic pressure (RVSP), myocardial capillary density (CD), and mRNA/protein expression of HIF-1α, VEGF, and Bcl-2 in rat myocardial tissue were determined. Apoptotic cell number was determined by TUNEL staining, and concentrations of malondialdehyde (MDA) and superoxide dismutase (SOD) were measured. RESULTS IH treatment for 1, 7, 14, and 28 days reduced the myocardial infarction size, whereas IH for 28 days increased the RVSP, ratio of right to left ventricle weight (RV/LV+S), and CD. IH up-regulated the mRNA and protein levels of HIF-1α, VEGF, and Bcl-2 both under normal and I/R conditions. The induced expression of HIF-1α and VEGF by IH reached a peak after 7 days of treatment. Moreover, IH for 28 days induced cardiomyocyte apoptosis, whereas prior treatment with IH for 1, 7, 14, and 28 days all markedly attenuated the apoptosis effected by the subsequent I/R injury. IH also decreased the concentrations of MDA but increased those of SOD in myocardial tissue of both in normal rats and following I/R. CONCLUSIONS The present study demonstrates that short-term IH protects the heart from I/R injury through inhibiting apoptosis and oxidative stress. The up-regulation of HIF-1α and VEGF by short-term IH may participate in the cardioprotective effect of IH.
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Affiliation(s)
- Zhang Wang
- Department of Geriatrics, The First Affiliated Hospital, Third Military Medical University, Chongqing, China
| | - Liang-Yi Si
- Department of Geriatrics, The First Affiliated Hospital, Third Military Medical University, Chongqing, China
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16
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Sanchis-Gomar F, Viña J, Lippi G. Intermittent hypobaric hypoxia applicability in myocardial infarction prevention and recovery. J Cell Mol Med 2012; 16:1150-4. [PMID: 22151473 PMCID: PMC4365893 DOI: 10.1111/j.1582-4934.2011.01508.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Intermittent hypobaric hypoxia (IHH) has been the focus of important research in cardioprotection, and it has been associated with several mechanisms. Intermittent hypobaric hypoxia inhibits prolyl hydroxylases (PHD) activity, increasing the stabilization of hypoxia-inducible factor-1 (HIF-1) and activating crucial adaptative genes. It has been hence suggested that IHH might be a simple intervention, which may offer a thoughtful benefits to patients with acute myocardial infarction and no complications. Nevertheless, several doubts exist as to whether IHH is a really safe technique, with little to no complications in post-myocardial infarction patients. Intermittent hypobaric hypoxia might produce instead unfavourable changes such as impairment of vascular hemodynamics and hypertensive response, increased risk of hemoconcentration and thrombosis, cardiac rhythm perturbations, coronary artery disease and heart failure, insulin resistance, steatohepatitis and even high-altitude pulmonary oedema in susceptible or nonacclimatized patients. Although intermittent and chronic exposures seem effective in cardioprotection, IHH safety issues have been mostly overlooked, so that assorted concerns should be raised about the opportunity to use IHH in the post-myocardial infarction period. Several IHH protocols used in some studies were also aggressive, which would hamper their widespread introduction within the clinical practice. As such, further research is needed before IHH can be widely advocated in myocardial infarction prevention and recovery.
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Affiliation(s)
- Fabian Sanchis-Gomar
- Faculty of Medicine, Department of Physiology, University of Valencia, Valencia, Spain.
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17
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Cardiac response to chronic intermittent hypoxia with a transition from adaptation to maladaptation: the role of hydrogen peroxide. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2012; 2012:569520. [PMID: 22685619 PMCID: PMC3364002 DOI: 10.1155/2012/569520] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 03/20/2012] [Indexed: 12/13/2022]
Abstract
Obstructive sleep apnea (OSA) is a highly prevalent respiratory disorder of sleep, and associated with chronic intermittent hypoxia (CIH). Experimental evidence indicates that CIH is a unique physiological state with potentially “adaptive” and “maladaptive” consequences for cardio-respiratory homeostasis. CIH is also a critical element accounting for most of cardiovascular complications of OSA. Cardiac response to CIH is time-dependent, showing a transition from cardiac compensative (such as hypertrophy) to decompensating changes (such as failure). CIH-provoked mild and transient oxidative stress can induce adaptation, but severe and persistent oxidative stress may provoke maladaptation. Hydrogen peroxide as one of major reactive oxygen species plays an important role in the transition of adaptive to maladaptive response to OSA-associated CIH. This may account for the fact that although oxidative stress has been recognized as a driver of cardiac disease progression, clinical interventions with antioxidants have had little or no impact on heart disease and progression. Here we focus on the role of hydrogen peroxide in CIH and OSA, trying to outline the potential of antioxidative therapy in preventing CIH-induced cardiac damage.
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18
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Anderson JD, Honigman B. The effect of altitude-induced hypoxia on heart disease: do acute, intermittent, and chronic exposures provide cardioprotection? High Alt Med Biol 2011; 12:45-55. [PMID: 21452965 DOI: 10.1089/ham.2010.1021] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
With the global prevalence of heart disease continuing to increase and large populations living at altitude around the world, we review the concept of altitude and cardioprotection. Current epidemiologic data, as well as the basic science and molecular mechanisms involved in acute, intermittent, and chronic exposure to altitude, are discussed. Intermittent and chronic exposures have been demonstrated to increase coronary vasculature, decrease infarction size, and provide more efficient metabolism and better cardiac functional recovery postischemia. Mechanisms demonstrated in these situations include those mediated by the hypoxia inducible factor, as well as reactive oxygen species, certain ion channels, and protein kinases. Although current epidemiologic studies are difficult to interpret owing to many confounders, many studies point to the possibility that living at altitude provides cardiovascular protection. Further research is needed to determine if the bench studies showing mechanisms consistent with cardioprotection translate to the population living at altitude.
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Affiliation(s)
- John D Anderson
- Department of Emergency Medicine, Denver Health Medical Center, Denver, Colorado, USA.
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19
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Proteomic analysis of mitochondrial proteins in cardiomyocytes from rats subjected to intermittent hypoxia. Eur J Appl Physiol 2011; 112:1037-46. [PMID: 21735218 DOI: 10.1007/s00421-011-2050-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Accepted: 06/15/2011] [Indexed: 10/18/2022]
Abstract
Intermittent hypoxia (IH) markedly enhances cardiac tolerance against ischemia/reperfusion injury, but its mechanism and molecular basis remain unclear. For exploring the expression of mitochondrial proteins induced by IH, two-dimensional electrophoresis and Thermo Finnigan LTQ mass spectrometer (MS) were applied. After comparing the protein profiles of myocardial mitochondria between IH and normoxic hearts, 14 protein spots were found to be altered more than threefold between the two groups, 11 of which were identified by Finnigan LTQ MS. Among these 11 proteins, 9 were involved in energy metabolism, including 7 that were increased after IH. The latter were identified as aldehyde dehydrogenase, methylmalonate-semialdehyde dehydrogenase, ATP synthase β chain, mitochondrial aconitase, malate dehydrogenase, electron transfer flavoprotein α subunit and sirtuin 5. Two other proteins, ubiquinol-cytochrome C reductase iron-sulfur subunit and aspartate aminotransferase, were decreased after IH. Biochemical tests for energy metabolism in mitochondria supported the proteomic results. IH exposure also increased the expression of a molecular chaperone-heat shock protein 60 and an antioxidant protein, peroxiredoxin 5. These findings will provide clues for understanding the mechanism of IH-induced cardiac protection and may lead to the development of interventional strategies designed to utilize the advantages of IH clinically.
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20
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Guo HC, Guo F, Zhang LN, Zhang R, Chen Q, Li JX, Yin J, Wang YL. Enhancement of Na/K pump activity by chronic intermittent hypobaric hypoxia protected against reperfusion injury. Am J Physiol Heart Circ Physiol 2011; 300:H2280-7. [DOI: 10.1152/ajpheart.01164.2010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Chronic intermittent hypobaric hypoxia (CIHH) has been shown to attenuate intracellular Na+ accumulation and Ca2+ overload during ischemia and reperfusion (I/R), both of which are closely related to the outcome of myocardial damage. Na/K pump plays an essential role in maintaining the equilibrium of intracellular Na+ and Ca2+ during I/R. It has been shown that enhancement of Na/K pump activity by ischemic preconditioning may be involved in the cardiac protection. Therefore, we tested whether Na/K pump was involved in the cardioprotection by CIHH. We found that Na/K pump current in cardiac myocytes of guinea pigs exposed to CIHH increased 1.45-fold. The K 1 and f 1, which reflect the portion of α1-isoform of Na/K pump, dramatically decreased or increased, respectively, in CIHH myocytes. Western blot analysis revealed that CIHH increased the protein expression of the α1-isoform by 76%, whereas the protein expression of the α2-isoform was not changed significantly. Na/K pump current was significantly suppressed in simulated I/R, and CIHH preserved the Na/K pump current. CIHH significantly improved the recovery of cell length and contraction during reperfusion. Furthermore, inhibition of Na/K pump by ouabain attenuated the protective effect afforded by CIHH. Collectively, these data suggest that the increase of Na/K pump activity following CIHH is due to the upregulating α1-isoform of Na/K pump, which may be one of the mechanisms of CIHH against I/R-induced injury.
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Affiliation(s)
- Hui-cai Guo
- Departments of 1Pharmacology and
- Toxicology, Hebei Medical University, Shijiazhuang, China
| | - Fang Guo
- Departments of 1Pharmacology and
| | | | - Rong Zhang
- Toxicology, Hebei Medical University, Shijiazhuang, China
| | - Qing Chen
- Toxicology, Hebei Medical University, Shijiazhuang, China
| | | | - Jian Yin
- Departments of 1Pharmacology and
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21
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Shimoda LA, Polak J. Hypoxia. 4. Hypoxia and ion channel function. Am J Physiol Cell Physiol 2011; 300:C951-67. [PMID: 21178108 PMCID: PMC3093942 DOI: 10.1152/ajpcell.00512.2010] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Accepted: 12/16/2010] [Indexed: 12/19/2022]
Abstract
The ability to sense and respond to oxygen deprivation is required for survival; thus, understanding the mechanisms by which changes in oxygen are linked to cell viability and function is of great importance. Ion channels play a critical role in regulating cell function in a wide variety of biological processes, including neuronal transmission, control of ventilation, cardiac contractility, and control of vasomotor tone. Since the 1988 discovery of oxygen-sensitive potassium channels in chemoreceptors, the effect of hypoxia on an assortment of ion channels has been studied in an array of cell types. In this review, we describe the effects of both acute and sustained hypoxia (continuous and intermittent) on mammalian ion channels in several tissues, the mode of action, and their contribution to diverse cellular processes.
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Affiliation(s)
- Larissa A Shimoda
- Div. of Pulmonary and Critical Care Medicine, Johns Hopkins University, 5501 Hopkins Bayview Circle, Baltimore, MD 21224, USA.
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22
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Up-regulation and redistribution of protein kinase C-δ in chronically hypoxic heart. Mol Cell Biochem 2010; 345:271-82. [DOI: 10.1007/s11010-010-0581-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Accepted: 08/27/2010] [Indexed: 12/29/2022]
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Guan Y, Gao L, Ma HJ, Li Q, Zhang H, Yuan F, Zhou ZN, Zhang Y. Chronic intermittent hypobaric hypoxia decreases β-adrenoceptor activity in right ventricular papillary muscle. Am J Physiol Heart Circ Physiol 2010; 298:H1267-72. [DOI: 10.1152/ajpheart.00410.2009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Chronic intermittent hypobaric hypoxia (CIHH) has an effective cardiac protection against ischemia-reperfusion injury. However, the underlying mechanisms are not fully known. It has been shown that blockade of β-adrenergic receptor exerts anti-arrhythmic action and improves cardiac remodeling in ischemic myocardium. Thus we determined the influence of CIHH on β-adrenergic receptor activity in right ventricular papillary muscle of rats. We found that the action potential duration in right ventricular papillary muscle was significantly longer in CIHH rats than in control rats. Activation of β-adrenergic receptor with dl-isoproterenol dose-dependently increased action potential duration and the contractility in right ventricular papillary muscle. In CIHH rats, the prolonged effect of dl-isoproterenol on action potential duration and the positive inotropic effect were significantly decreased compared with that in control rats. Furthermore, radioligand-binding experiments revealed that the density and affinity of β-adrenergic receptor in right ventricular myocardium was significantly lower in CIHH rats. In addition, Western blot analysis revealed that the membrane-bound G protein Gsα expression level in cardiac myocardium was significantly lower in CIHH rats than that in control rats. Collectively, these data suggest that CIHH suppresses β-adrenergic receptor action in right ventricular papillary muscle through decreasing receptor density and affinity, as well as membrane-bound Gsα. This mechanism may be involved in the cardiac protective effect of CIHH.
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Affiliation(s)
- Yue Guan
- Department of Physiology, Hebei Medical University, Shijiazhuang, China; and
| | - Lu Gao
- Department of Physiology, Hebei Medical University, Shijiazhuang, China; and
| | - Hui-Jie Ma
- Department of Physiology, Hebei Medical University, Shijiazhuang, China; and
| | - Qian Li
- Department of Physiology, Hebei Medical University, Shijiazhuang, China; and
| | - Hao Zhang
- Department of Physiology, Hebei Medical University, Shijiazhuang, China; and
| | - Fang Yuan
- Department of Physiology, Hebei Medical University, Shijiazhuang, China; and
| | - Zhao-Nian Zhou
- Laboratory of Hypoxic Cardiovascular Physiology, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Yi Zhang
- Department of Physiology, Hebei Medical University, Shijiazhuang, China; and
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24
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Zhang Y, Zhong N, Zhou ZN. Effects of Chronic Intermittent Hypobaric Hypoxia on the L-type Calcium Current in Rat Ventricular Myocytes. High Alt Med Biol 2010; 11:61-7. [DOI: 10.1089/ham.2009.1011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Yi Zhang
- Department of Physiology, Hebei Medical University, Shijiazhuang, China
| | - Ning Zhong
- Gladstone Institutes of Cardiovascular and Neurological Diseases, University of California, San Francisco, California, USA
| | - Zhao-Nian Zhou
- Laboratory of Hypoxia Physiology, Shanghai Institute of Biological Sciences, Chinese Academy of Science, Shanghai, China
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25
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Guo HC, Zhang Z, Zhang LN, Xiong C, Feng C, Liu Q, Liu X, Shi XL, Wang YL. Chronic intermittent hypobaric hypoxia protects the heart against ischemia/reperfusion injury through upregulation of antioxidant enzymes in adult guinea pigs. Acta Pharmacol Sin 2009; 30:947-55. [PMID: 19543301 PMCID: PMC4085733 DOI: 10.1038/aps.2009.57] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Accepted: 04/14/2009] [Indexed: 11/09/2022] Open
Abstract
AIM To investigate the protection and the anti-oxidative mechanism afforded by chronic intermittent hypobaric hypoxia (CIHH) against ischemia/reperfusion (I/R) injury in guinea pig hearts. METHODS Adult male guinea pigs were exposed to CIHH by mimicking a 5000 m high altitude (p(B)=404 mmHg, p(O2)=84 mmHg) in a hypobaric chamber for 6 h/day for 28 days. Langendorff-perfused isolated guinea pig hearts were used to measure variables of left ventricular function during baseline perfusion, ischemia and the reperfusion period. The activity and protein expression of antioxidant enzymes in the left myocardium were evaluated using biochemical methods and Western blotting, respectively. Intracellular reactive oxygen species (ROS) were assessed using ROS-sensitive fluorescence. RESULTS After 30 min of global no-flow ischemia followed by 60 min of reperfusion, myocardial function had better recovery rates in CIHH guinea pig hearts than in control hearts. The activity and protein expression of superoxide dismutase (SOD) and catalase (CAT) were significantly increased in the myocardium of CIHH guinea pigs. Pretreatment of control hearts with an antioxidant mixture containing SOD and CAT exerted cardioprotective effects similar to CIHH. The irreversible CAT inhibitor aminotriazole (ATZ) abolished the cardioprotection of CIHH. Cardiac contractile dysfunction and oxidative stress induced by exogenous hydrogen peroxide (H(2)O(2)) were attenuated by CIHH and CAT. CONCLUSIONS These data suggest that CIHH protects the heart against I/R injury through upregulation of antioxidant enzymes in guinea pig.Acta Pharmacologica Sinica (2009) 30: 947-955; doi: 10.1038/aps.2009.57; published online 22 June 2009.
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Affiliation(s)
- Hui-cai Guo
- Department of Pharmacology, Hebei Medical University, Shijiazhuang 050017, China
| | - Zhe Zhang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang 050017, China
| | - Li-nan Zhang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang 050017, China
| | - Chen Xiong
- Department of Pharmacology, Hebei Medical University, Shijiazhuang 050017, China
| | - Chen Feng
- Department of Pharmacology, Hebei Medical University, Shijiazhuang 050017, China
| | - Qian Liu
- Department of Pharmacology, Hebei Medical University, Shijiazhuang 050017, China
| | - Xu Liu
- Department of Pharmacology, Hebei Medical University, Shijiazhuang 050017, China
| | - Xiao-lu Shi
- Department of Pharmacology, Hebei Medical University, Shijiazhuang 050017, China
| | - Yong-li Wang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang 050017, China
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Yu Z, Wang ZH, Yang HT. Calcium/calmodulin-dependent protein kinase II mediates cardioprotection of intermittent hypoxia against ischemic-reperfusion-induced cardiac dysfunction. Am J Physiol Heart Circ Physiol 2009; 297:H735-42. [PMID: 19525372 DOI: 10.1152/ajpheart.01164.2008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Intermittent high-altitude (IHA) hypoxia-induced cardioprotection against ischemia-reperfusion (I/R) injury is associated with the preservation of sarcoplasmic reticulum (SR) function. Although Ca(2+)/calmodulin (CaM)-dependent protein kinase II (CaMKII) and phosphatase are known to modulate the function of cardiac SR under physiological conditions, the status of SR CaMKII and phosphatase during I/R in the hearts from IHA hypoxic rats is unknown. In the present study, we determined SR and cytosolic CaMKII activity during preischemia and I/R (30 min/30 min) in perfused hearts from normoxic and IHA hypoxic rats. The left ventricular contractile recovery, SR CaMKII activity as well as phosphorylation of phospholamban at Thr(17), and Ca(2+)/CaM-dependent SR Ca(2+)-uptake activity were depressed in the I/R hearts from normoxic rats, whereas these changes were prevented in the hearts from IHA hypoxic rats. Such beneficial effects of IHA hypoxia were lost by treating the hearts with a specific CaMKII inhibitor, KN-93. I/R also depressed cytosolic CaMKII and SR phosphatase activity, but these alterations remained unchanged in IHA hypoxic group. Furthermore, we found that the autophosphorylation at Thr(287), which confers Ca(2+)/CaM-independent activity, was not altered by I/R in both groups. These findings indicate that preservation of SR CaMKII activity plays an important role in the IHA hypoxia-induced cardioprotection against I/R injury via maintaining SR Ca(2+)-uptake activity.
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Affiliation(s)
- Zhuo Yu
- Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Jiao Tong University School of Medicine and Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Ruijin Hospital, Shanghai, China
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Jung ME, Simpkins JW, Wilson AM, Downey HF, Mallet RT. Intermittent hypoxia conditioning prevents behavioral deficit and brain oxidative stress in ethanol-withdrawn rats. J Appl Physiol (1985) 2008; 105:510-7. [PMID: 18499779 DOI: 10.1152/japplphysiol.90317.2008] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Intermittent hypoxia (IH) has been found to protect brain from ischemic injury. We investigated whether IH mitigates brain oxidative stress and behavioral deficits in rats subjected to ethanol intoxication and abrupt ethanol withdrawal (EW). The effects of IH on overt EW behavioral signs, superoxide generation, protein oxidation, and mitochondrial permeability transition pore (PTP) opening were examined. Male rats consumed dextrin or 6.5% (wt/vol) ethanol for 35 days. During the last 20 days, rats were treated with repetitive (5-8 per day), brief (5-10 min) cycles of hypoxia (9.5-10% inspired O2) separated by 4-min normoxia exposures. Cerebellum, cortex, and hippocampus were biopsied on day 35 of the diet or at 24 h of EW. Superoxide and protein carbonyl contents in tissue homogenates and absorbance decline at 540 nm in mitochondrial suspensions served as indicators of oxidative stress, protein oxidation, and PTP opening, respectively. Although IH altered neither ethanol consumption nor blood ethanol concentration, it sharply lowered the severity of EW signs including tremor, tail rigidity, and startle response. Compared with dextrin and ethanol per se, in the three brain regions, EW increased superoxide and protein carbonyl contents and accelerated PTP opening in a manner ameliorated by IH. Administration of antioxidant N-acetylcysteine throughout the IH program abrogated the reductions in EW signs and superoxide content, implicating IH-induced ROS as mediators of the salutary adaptations. We conclude that IH conditioning during chronic ethanol consumption attenuates oxidative damage to the brain and mitigates behavioral abnormalities during subsequent EW. IH-induced ROS may evoke this powerful protection.
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Affiliation(s)
- Marianna E Jung
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, TX 76107-2699, USA
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28
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Abstract
Obstructive sleep apnea (OSA) is associated with cardiovascular diseases such as hypertension through mechanisms involving intermittent hypoxia (IH). However, it is not yet clear whether IH directly affects the heart. In a mouse model of OSA, we found that IH causes time-dependent alterations of the susceptibility of the heart to oxidative stress. Acute IH can exert preconditioning-like cardioprotection, in part, through the transcriptional activation of genes such as bcl-x(L) and gata4. We cloned the mouse gata4 promoter and identified an IH-responsive region. The exposure of mice to prolonged IH results in the increased susceptibility of the heart to ischemia-reperfusion injury by increasing the oxidative stress status. This might resemble conditions of OSA patients. In our mouse model, further exposure to prolonged IH allowed reversal of the enhancement of myocardial damage. Understanding the complex effects of IH on the heart should help ultimately to develop therapeutic strategies against OSA-induced complications.
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Affiliation(s)
- Ah-Mee Park
- Department of Pharmacology, Georgetown University Medical Center, Washington, DC 20057, USA.
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29
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Liimatta E, Kantola AM, Hassinen IE. Dual probe fluorescence monitoring of intracellular free calcium during ischemia in mouse heart by using continuous compensation for pH dependence of the dissociation constant of Fura-2, and the interference of myoglobin. ACTA ACUST UNITED AC 2007; 70:547-54. [PMID: 17316820 DOI: 10.1016/j.jbbm.2007.01.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2006] [Revised: 12/14/2006] [Accepted: 01/05/2007] [Indexed: 11/22/2022]
Abstract
Mitochondrial damage is the main source of cellular injury upon ischemia-reperfusion, and calcium loading has been implicated in this phenomenon. The use of optical probes for calcium monitoring of the intact heart is hampered by internal filter effects of intracellular hemoproteins, endogenous fluorescence, and their sensitivity to pH. We describe here a method for measurement of intracellular free calcium in isolated myoglobin-deficient perfused mouse hearts under conditions of large intracellular pH fluctuations by simultaneous fluorescence monitoring of the calcium-probe Fura-2 and the pH probe BCECF through dual wavelength excitation of both probes. In myoglobin-containing mouse heart endogenous chromophores interfere with Fura-2 fluorometry. It is shown that a paradoxical decrease in Fura-2 fluorescence occurs during ischemia in isolated mouse hearts. Simultaneous recording of BCECF fluorescence (calibrated against pH measurement with phosphorus NMR) and data reduction based on continual recalculation of the apparent dissociation constant of the calcium-probe complex revealed that a marked increase in intracellular free calcium occurs, and that the Fura-2 fluorescence decrease was caused by an increase in dissociation constant due to intracellular acidification. Intracellular free calcium rose almost linearly during a 20-min period of ischemia and returned to basal values rapidly upon the commencement of perfusion.
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Affiliation(s)
- Erkki Liimatta
- Department of Medical Biochemistry and Molecular Biology, University of Oulu, Finland
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30
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Li J, Zhang H, Zhu WZ, Yu Z, Guo A, Yang HT, Zhou ZN. Preservation of the pHi during ischemia via PKC by intermittent hypoxia. Biochem Biophys Res Commun 2007; 356:329-33. [PMID: 17359938 DOI: 10.1016/j.bbrc.2007.02.128] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2007] [Accepted: 02/13/2007] [Indexed: 11/23/2022]
Abstract
In intermittent hypoxia adaptation (IHA) rat cardiomyocytes, the relationship between activated protein kinase C and intracellular acidification regulation during ischemia-reperfusion (I/R) was tested. Using [H(+)] indicator BCECF-AM, we analyzed the alterations of intracellular pH (pH(i)) in normoxia and IHA rat cardiomyocytes during I/R. With the time of ischemia, the pH(i) decreased progressively in normal cardiomyocytes, but fewer alterations in IHA myocytes. Treatment of IHA and normoxia cardiomyocytes with 5 microM chelerythrine delayed the pH(i) recovery during post-ischemia. In contrast, the application of 1 microM phorbol 12-myristate 13-acetate in normoxia cardiomyocytes preserved the pH(i) during I/R, which was similar to that in IHA cardiomyocytes. Our data suggest that the stable PKC activation might contribute to preservation of the pH(i), which may be beneficial to maintain cardiac function during I/R in IHA rats.
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Affiliation(s)
- Jun Li
- Laboratory of Molecular Cardiology, Institute of Health Sciences, Shanghai Jiao Tong University School of Medicine (SJTUSM) [corrected] Shanghai 200025, China
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31
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Ostadal B, Kolar F. Cardiac adaptation to chronic high-altitude hypoxia: beneficial and adverse effects. Respir Physiol Neurobiol 2007; 158:224-36. [PMID: 17442631 DOI: 10.1016/j.resp.2007.03.005] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2007] [Revised: 03/06/2007] [Accepted: 03/06/2007] [Indexed: 01/28/2023]
Abstract
This review deals with the capability of the heart to adapt to chronic hypoxia in animals exposed to either natural or simulated high altitude. From the broad spectrum of related issues, we focused on the development and reversibility of both beneficial and adverse adaptive myocardial changes. Particular attention was paid to cardioprotective effects of adaptation to chronic high-altitude hypoxia and their molecular mechanisms. Moreover, interspecies and age differences in the cardiac sensitivity to hypoxia-induced effects in various experimental models were emphasized.
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Affiliation(s)
- B Ostadal
- Centre for Cardiovascular Research, Institute of Physiology, Academy of Sciences of the Czech Republic, Videnska 1083, 142 20 Prague 4, Czech Republic.
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32
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Park AM, Suzuki YJ. Effects of intermittent hypoxia on oxidative stress-induced myocardial damage in mice. J Appl Physiol (1985) 2007; 102:1806-14. [PMID: 17272404 DOI: 10.1152/japplphysiol.01291.2006] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Obstructive sleep apnea is associated with increased risk for cardiovascular diseases. As obstructive sleep apnea is characterized by episodic cycles of hypoxia and normoxia during sleep, we investigated effects of intermittent hypoxia (IH) on ischemia-reperfusion-induced myocardial injury. C57BL/6 mice were subjected to IH (2 min 6% O(2) and 2 min 21% O(2)) for 8 h/day for 1, 2, or 4 wk; isolated hearts were then subjected to ischemia-reperfusion. IH for 1 or 2 wk significantly enhanced ischemia-reperfusion-induced myocardial injury. However, enhanced cardiac damage was not seen in mice treated with 4 wk of IH, suggesting that the heart has adapted to chronic IH. Ischemia-reperfusion-induced lipid peroxidation and protein carbonylation were enhanced with 2 wk of IH, while, with 4 wk, oxidative stress was normalized to levels in animals without IH. H(2)O(2) scavenging activity in adapted hearts was higher after ischemia-reperfusion, suggesting the increased antioxidant capacity. This might be due to the involvement of thioredoxin, as the expression level of this protein was increased, while levels of other antioxidant enzymes were unchanged. In the heart from mice treated with 2 wk of IH, ischemia-reperfusion was found to decrease thioredoxin. Ischemia-reperfusion injury can also be enhanced when thioredoxin reductase was inhibited in control hearts. These results demonstrate that IH changes the susceptibility of the heart to oxidative stress in part via alteration of thioredoxin.
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Affiliation(s)
- Ah-Mee Park
- Dept. of Pharmacology, Georgetown University Medical Center, Washington, DC 20057, USA.
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33
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Yeung HM, Kravtsov GM, Ng KM, Wong TM, Fung ML. Chronic intermittent hypoxia alters Ca2+ handling in rat cardiomyocytes by augmented Na+/Ca2+ exchange and ryanodine receptor activities in ischemia-reperfusion. Am J Physiol Cell Physiol 2007; 292:C2046-56. [PMID: 17267548 DOI: 10.1152/ajpcell.00458.2006] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study examined Ca(2+) handling mechanisms involved in cardioprotection induced by chronic intermittent hypoxia (CIH) against ischemia-reperfusion (I/R) injury. Adult male Sprague-Dawley rats were exposed to 10% inspired O(2) continuously for 6 h daily from 3, 7, and 14 days. In isolated perfused hearts subjected to I/R, CIH-induced cardioprotection was most significant in the 7-day group with less infarct size and lactate dehydrogenase release, compared with the normoxic group. The I/R-induced alterations in diastolic Ca(2+) level, amplitude, time-to-peak, and the decay time of both electrically and caffeine-induced Ca(2+) transients measured by spectrofluorometry in isolated ventricular myocytes of the 7-day CIH group were less than that of the normoxic group, suggesting an involvement of altered Ca(2+) handling of the sarcoplasmic reticulum (SR) and sarcolemma. We further determined the protein expression and activity of (45)Ca(2+) flux of SR-Ca(2+)-ATPase, ryanodine receptor (RyR) and sarcolemmal Na(+)/Ca(2+) exchange (NCX) in ventricular myocytes from the CIH and normoxic groups before and during I/R. There were no changes in expression levels of the Ca(2+)-handling proteins but significant increases in the RyR and NCX activities were remarkable during I/R in the CIH but not the normoxic group. The augmented RyR and NCX activities were abolished, respectively, by PKA inhibitor (0.5 microM KT5720 or 0.5 microM PKI(14-22)) and PKC inhibitor (5 microM chelerythrine chloride or 0.2 microM calphostin C) but not by Ca(2+)/calmodulin-dependent protein kinase II inhibitor KN-93 (1 microM). Thus, CIH confers cardioprotection against I/R injury in rat cardiomyocytes by altered Ca(2+) handling with augmented RyR and NCX activities via protein kinase activation.
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Affiliation(s)
- Hang Mee Yeung
- Dept. of Physiology, University of Hong Kong, Pokfulam, Hong Kong
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Kolár F, Jezková J, Balková P, Breh J, Neckár J, Novák F, Nováková O, Tomásová H, Srbová M, Ost'ádal B, Wilhelm J, Herget J. Role of oxidative stress in PKC-δ upregulation and cardioprotection induced by chronic intermittent hypoxia. Am J Physiol Heart Circ Physiol 2007; 292:H224-30. [PMID: 16936002 DOI: 10.1152/ajpheart.00689.2006] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aim was to determine whether increased oxidative stress during the adaptation to chronic intermittent hypoxia (CIH) plays a role in the induction of improved cardiac ischemic tolerance. Adult male Wistar rats were exposed to CIH in a hypobaric chamber (7,000 m, 8 h/day, 5 days/wk, 24–30 exposures). Half of the animals received antioxidant N-acetylcysteine (NAC; 100 mg/kg) daily before the exposure; the remaining rats received saline. Control rats were kept under normoxia and treated in a corresponding manner. One day after the last exposure (and/or NAC injection), anesthetized animals were subject to 20 min of coronary artery occlusion and 3 h of reperfusion for determination of infarct size. In parallel subgroups, biochemical analyses of the left ventricular myocardium were performed. Adaptation to CIH reduced infarct size from 56.7 ± 4.5% of the area at risk in the normoxic controls to 27.7 ± 4.9%. NAC treatment decreased the infarct size in the controls to 42.0 ± 3.4%, but it abolished the protection provided by CIH (to 41.1 ± 4.9%). CIH decreased the reduced-to-oxidized glutathione ratio and increased the relative amount of PKC isoform-δ in the particulate fraction; NAC prevented these effects. The expression of PKC-ε was decreased by CIH and not affected by NAC. Activities of superoxide dismutase, catalase, and glutathione peroxidase were affected by neither CIH nor NAC treatment. It is concluded that oxidative stress associated with CIH plays a role in the development of increased cardiac ischemic tolerance. The infarct size-limiting mechanism of CIH seems to involve the PKC-δ-dependent pathway but apparently not the increased capacity of major antioxidant enzymes.
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Affiliation(s)
- Frantisek Kolár
- Inst. of Physiology, Academy of Sciences of the Czech Republic, Videnska 1083, 142 20 Prague 4, Czech Republic.
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35
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Ramachandran S, Desai NM, Goers TA, Benshoff N, Olack B, Shenoy S, Jendrisak MD, Chapman WC, Mohanakumar T. Improved islet yields from pancreas preserved in perflurocarbon is via inhibition of apoptosis mediated by mitochondrial pathway. Am J Transplant 2006; 6:1696-703. [PMID: 16827873 DOI: 10.1111/j.1600-6143.2006.01368.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Islet transplantation is a treatment option for type I diabetic patients. Preservation of human pancreata prior to islet isolation using two-layer method with perfluorocarbon (PFC) and University of Wisconsin solution (UW) results in twofold increase in islet yields. The objective of this study was to determine the mechanism by which islets undergo apoptosis and determine PFC's effects on this process. Gene array analysis was used to analyze the expression of pro- and anti-apoptotic genes in islets isolated from pancreata preserved under varying conditions. A 12-fold increase in the expression of inhibitor of apoptosis (IAP) and survivin was observed in islets isolated from pancreata preserved in PFC. This was accompanied by decreased expression of BAD (3.7-fold), BAX (2.7-fold) and caspases (5.2-fold). Levels of activated caspase-9 (77.98%), caspase-2 (61.5%), caspase-3 (68.3%) and caspase-8 (37.2%) were also reduced. 'Rescue' of pancreata after storage (12 h) in UW by preservation using PFC also resulted in a down-regulation of pro-apoptotic genes and inhibition of caspase activation. Apoptosis observed in islets from all groups was mainly mitochondria-dependent, mediated by change in redox potential initiated by hypoxia. We demonstrate that reduction in hypoxia of pancreata preserved using PFC leads to significant up-regulation of anti-apoptotic and inhibition of pro-apoptotic genes.
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Affiliation(s)
- S Ramachandran
- Department of Surgery, Washington University School of Medicine, St. Louis, MO, USA
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36
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Chen L, Lu XY, Li J, Fu JD, Zhou ZN, Yang HT. Intermittent hypoxia protects cardiomyocytes against ischemia-reperfusion injury-induced alterations in Ca2+ homeostasis and contraction via the sarcoplasmic reticulum and Na+/Ca2+ exchange mechanisms. Am J Physiol Cell Physiol 2005; 290:C1221-9. [PMID: 16306124 DOI: 10.1152/ajpcell.00526.2005] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have previously demonstrated that intermittent high-altitude (IHA) hypoxia significantly attenuates ischemia-reperfusion (I/R) injury-induced excessive increase in resting intracellular Ca(2+) concentrations ([Ca(2+)](i)). Because the sarcoplasmic reticulum (SR) and Na(+)/Ca(2+) exchanger (NCX) play crucial roles in regulating [Ca(2+)](i) and both are dysfunctional during I/R, we tested the hypothesis that IHA hypoxia may prevent I/R-induced Ca(2+) overload by maintaining Ca(2+) homeostasis via SR and NCX mechanisms. We thus determined the dynamics of Ca(2+) transients and cell shortening during preischemia and I/R injury in ventricular cardiomyocytes from normoxic and IHA hypoxic rats. IHA hypoxia did not affect the preischemic dynamics of Ca(2+) transients and cell shortening, but it significantly suppressed the I/R-induced increase in resting [Ca(2+)](i) levels and attenuated the depression of the Ca(2+) transients and cell shortening during reperfusion. Moreover, IHA hypoxia significantly attenuated I/R-induced depression of the protein contents of SR Ca(2+) release channels and/or ryanodine receptors (RyRs) and SR Ca(2+) pump ATPase (SERCA2) and SR Ca(2+) release and uptake. In addition, a delayed decay rate time constant of Ca(2+) transients and cell shortening of Ca(2+) transients observed during ischemia was accompanied by markedly inhibited NCX currents, which were prevented by IHA hypoxia. These findings indicate that IHA hypoxia may preserve Ca(2+) homeostasis and contraction by preserving RyRs and SERCA2 proteins as well as NCX activity during I/R.
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Affiliation(s)
- Le Chen
- Laboratory of Molecular Cardiology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, and Shanghai Jiao Tong University School of Medicine, 225 Chong Qing Nan Rd., #1 Bldg., Shanghai 200025, China
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37
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Bae S, Zhang L. Gender Differences in Cardioprotection against Ischemia/Reperfusion Injury in Adult Rat Hearts: Focus on Akt and Protein Kinase C Signaling. J Pharmacol Exp Ther 2005; 315:1125-35. [PMID: 16099927 DOI: 10.1124/jpet.105.090803] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Previous studies have reported the sex differences in heart susceptibility to ischemia/reperfusion (I/R) injury, but the mechanisms are not understood. The present study tested the hypothesis that Akt and protein kinase C (PKC)epsilon play an important role in the sexual dimorphism of heart susceptibility to I/R injury. Isolated hearts from 2-month-old male and female rats were subjected to I/R in the Langendorff preparation. The postischemic recovery of left ventricular function was significantly better, and infarct size was significantly smaller in female (37.1 +/- 1.9%) than in male (48.3 +/- 2.3%) hearts after 25-min ischemia followed by 2-h reperfusion. Inhibition of phosphatidylinositol 3-kinase/Akt pathway by wortmannin or PKC by chelerythrine chloride before ischemia significantly reduced postischemic recovery and increased infarct size in female but not male hearts. There were no differences in myocardial protein levels of heat shock protein 70, Akt, and PKCepsilon, respectively, between male and female rats. However, the ratio of phosphorylated (p)-Akt/Akt (0.58 +/- 0.05 versus 0.22 +/- 0.04; P < 0.05) and p-PKCepsilon/PKCepsilon (0.35 +/- 0.03 versus 0.22 +/- 0.02; P < 0.05) was significantly higher in female than in male hearts. In addition, there were significant increases in p-Akt and p-PKCepsilon levels during reperfusion in female but not in male hearts. The results suggest that increased p-Akt and p-PKCepsilon levels in female hearts contribute to the gender-related differences in heart susceptibility to I/R and play an important role in cardioprotection against I/R injury in females.
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Affiliation(s)
- Soochan Bae
- Center for Perinatal Biology, Department of Pharmacology and Physiology, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA
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38
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Xie Y, Zhu Y, Zhu WZ, Chen L, Zhou ZN, Yuan WJ, Yang HT. Role of dual-site phospholamban phosphorylation in intermittent hypoxia-induced cardioprotection against ischemia-reperfusion injury. Am J Physiol Heart Circ Physiol 2005; 288:H2594-602. [PMID: 15637115 DOI: 10.1152/ajpheart.00926.2004] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cardioprotection by intermittent high-altitude (IHA) hypoxia against ischemia-reperfusion (I/R) injury is associated with Ca(2+) overload reduction. Phospholamban (PLB) phosphorylation relieves cardiac sarcoplasmic reticulum (SR) Ca(2+)-pump ATPase, a critical regulator in intracellular Ca(2+) cycling, from inhibition. To test the hypothesis that IHA hypoxia increases PLB phosphorylation and that such an effect plays a role in cardioprotection, we compared the time-dependent changes in the PLB phosphorylation at Ser(16) (PKA site) and Thr(17) (CaMKII site) in perfused normoxic rat hearts with those in IHA hypoxic rat hearts submitted to 30-min ischemia (I30) followed by 30-min reperfusion (R30). IHA hypoxia improved postischemic contractile recovery, reduced the maximum extent of ischemic contracture, and attenuated I/R-induced depression in Ca(2+)-pump ATPase activity. Although the PLB protein levels remained constant during I/R in both groups, Ser(16) phosphorylation increased at I30 and 1 min of reperfusion (R1) but decreased at R30 in normoxic hearts. IHA hypoxia upregulated the increase further at I30 and R1. Thr(17) phosphorylation decreased at I30, R1, and R30 in normoxic hearts, but IHA hypoxia attenuated the depression at R1 and R30. Moreover, PKA inhibitor H89 abolished IHA hypoxia-induced increase in Ser(16) phosphorylation, Ca(2+)-pump ATPase activity, and the recovery of cardiac performance after ischemia. CaMKII inhibitor KN-93 also abolished the beneficial effects of IHA hypoxia on Thr(17) phosphorylation, Ca(2+)-pump ATPase activity, and the postischemic contractile recovery. These findings indicate that IHA hypoxia mitigates I/R-induced depression in SR Ca(2+)-pump ATPase activity by upregulating dual-site PLB phosphorylation, which may consequently contribute to IHA hypoxia-induced cardioprotection against I/R injury.
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Affiliation(s)
- Yan Xie
- Laboratory of Molecular Cardiology, Health Science Center, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences and Shanghai Second Medical Univ., Shanghai, China
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