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Zhu L, Zhang J, Zhou J, Lu Y, Huang S, Xiao R, Yu X, Zeng X, Liu B, Liu F, Sun M, Dai M, Hao Q, Li J, Wang T, Li T, Hu Q. Mitochondrial transplantation attenuates hypoxic pulmonary hypertension. Oncotarget 2018; 7:48925-48940. [PMID: 27419637 PMCID: PMC5226481 DOI: 10.18632/oncotarget.10596] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Accepted: 06/30/2016] [Indexed: 01/01/2023] Open
Abstract
Mitochondria are essential for the onset of hypoxia-induced pulmonary vasoconstriction and pulmonary vascular-remodeling, two major aspects underlying the development of pulmonary hypertension, an incurable disease. However, hypoxia induces relaxation of systemic arteries such as femoral arteries and mitochondrial heterogeneity controls the distinct responses of pulmonary versus femoral artery smooth muscle cells to hypoxia in vitro. The aim of this study was to determine whether mitochondrial heterogeneity can be experimentally exploited in vivo for a potential treatment against pulmonary hypertension. The intact mitochondria were transplanted into Sprague-Dawley rat pulmonary artery smooth muscle cells in vivo via intravenous administration. The immune-florescent staining and ultrastructural examinations on pulmonary arteries confirmed the intracellular distribution of exogenous mitochondria and revealed the possible mitochondrial transfer from pulmonary artery endothelial cells into smooth muscle cells in part through their intercellular space and intercellular junctions. The transplantation of mitochondria derived from femoral artery smooth muscle cells inhibited acute hypoxia-triggered pulmonary vasoconstriction, attenuated chronic hypoxia-induced pulmonary vascular remodeling, and thus prevented the development of pulmonary hypertension or cured the established pulmonary hypertension in rats exposed to chronic hypoxia. Our findings suggest that mitochondrial transplantation possesses potential implications for exploring a novel therapeutic and preventive strategy against pulmonary hypertension.
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Affiliation(s)
- Liping Zhu
- Department of Pathophysiology, School of Basic Medicine, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China.,Key Laboratory of Pulmonary Diseases of Ministry of Health, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China
| | - Jiwei Zhang
- Department of Pathophysiology, School of Basic Medicine, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China.,Key Laboratory of Pulmonary Diseases of Ministry of Health, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China.,Department of Pathology, Union Hospital, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China
| | - Juan Zhou
- Department of Pathophysiology, School of Basic Medicine, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China.,Key Laboratory of Pulmonary Diseases of Ministry of Health, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China.,Current address: Department of Clinical Laboratory of Xuzhou Central Hospital, Xuzhou, China
| | - Yankai Lu
- Department of Pathophysiology, School of Basic Medicine, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China.,Key Laboratory of Pulmonary Diseases of Ministry of Health, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China
| | - Songling Huang
- Department of Pathophysiology, School of Basic Medicine, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China.,Key Laboratory of Pulmonary Diseases of Ministry of Health, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China
| | - Rui Xiao
- Department of Pathophysiology, School of Basic Medicine, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China.,Key Laboratory of Pulmonary Diseases of Ministry of Health, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China
| | - Xiangyuan Yu
- Department of Pathophysiology, School of Basic Medicine, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China.,Key Laboratory of Pulmonary Diseases of Ministry of Health, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China
| | - Xianqin Zeng
- Department of Pathophysiology, School of Basic Medicine, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China.,Key Laboratory of Pulmonary Diseases of Ministry of Health, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China
| | - Bingxun Liu
- Department of Pathophysiology, School of Basic Medicine, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China.,Key Laboratory of Pulmonary Diseases of Ministry of Health, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China
| | - Fangbo Liu
- Department of Pathophysiology, School of Basic Medicine, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China.,Key Laboratory of Pulmonary Diseases of Ministry of Health, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China
| | - Mengxiang Sun
- Department of Pathophysiology, School of Basic Medicine, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China.,Key Laboratory of Pulmonary Diseases of Ministry of Health, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China
| | - Mao Dai
- Department of Pathophysiology, School of Basic Medicine, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China.,Key Laboratory of Pulmonary Diseases of Ministry of Health, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China
| | - Qiang Hao
- Department of Pathophysiology, School of Basic Medicine, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China.,Key Laboratory of Pulmonary Diseases of Ministry of Health, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China
| | - Jiansha Li
- Key Laboratory of Pulmonary Diseases of Ministry of Health, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China.,Department of Pathology, Tongji Hospital, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China
| | - Tao Wang
- Key Laboratory of Pulmonary Diseases of Ministry of Health, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China.,Department of Respiratory and Critical Care Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China
| | - Tongfei Li
- Department of Pathology, School of Basic Medical Sciences, Hubei University of Medicine, Shiyan, China
| | - Qinghua Hu
- Department of Pathophysiology, School of Basic Medicine, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China.,Key Laboratory of Pulmonary Diseases of Ministry of Health, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China
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Thompson JW, Narayanan SV, Perez-Pinzon MA. Redox signaling pathways involved in neuronal ischemic preconditioning. Curr Neuropharmacol 2013; 10:354-69. [PMID: 23730259 PMCID: PMC3520045 DOI: 10.2174/157015912804143577] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2012] [Revised: 07/23/2012] [Accepted: 08/16/2012] [Indexed: 12/28/2022] Open
Abstract
There is extensive evidence that the restoration of blood flow following cerebral ischemia contributes greatly to the pathophysiology of ischemia mediated brain injury. The initiating stimulus of reperfusion injury is believed to be the excessive production of reactive oxygen (ROS) and nitrogen (RNS) species by the mitochondria. ROS and RNS generation leads to mitochondrial protein, lipid and DNA oxidation which impedes normal mitochondrial physiology and initiates cellular death pathways. However not all ROS and RNS production is detrimental. It has been demonstrated that low levels of ROS production are protective and may serve as a trigger for activation of ischemic preconditioning. Ischemic preconditioning is a neuroprotective mechanism which is activated upon a brief sublethal ischemic exposure and is sufficient to provide protection against a subsequent lethal ischemic insult. Numerous proteins and signaling pathways have been implicated in the ischemic preconditioning neuroprotective response. In this review we examine the origin and mechanisms of ROS and RNS production following ischemic/reperfusion and the role of free radicals in modulating proteins associated with ischemic preconditioning neuroprotection.
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Affiliation(s)
- John W Thompson
- Cerebral Vascular Disease Research Center, Department of Neurology, University of Miami, Miller School of Medicine, Miami, Fl 33136
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3
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Hüttemann M, Lee I, Grossman LI, Doan JW, Sanderson TH. Phosphorylation of mammalian cytochrome c and cytochrome c oxidase in the regulation of cell destiny: respiration, apoptosis, and human disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 748:237-64. [PMID: 22729861 DOI: 10.1007/978-1-4614-3573-0_10] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The mitochondrial oxidative phosphorylation (OxPhos) system not only generates the vast majority of cellular energy, but is also involved in the generation of reactive oxygen species (ROS), and apoptosis. Cytochrome c (Cytc) and cytochrome c oxidase (COX) represent the terminal step of the electron transport chain (ETC), the proposed rate-limiting reaction in mammals. Cytc and COX show unique regulatory features including allosteric regulation, isoform expression, and regulation through cell signaling pathways. This chapter focuses on the latter and discusses all mapped phosphorylation sites based on the crystal structures of COX and Cytc. Several signaling pathways have been identified that target COX including protein kinase A and C, receptor tyrosine kinase, and inflammatory signaling. In addition, four phosphorylation sites have been mapped on Cytc with potentially large implications due to its multiple functions including apoptosis, a pathway that is overactive in stressed cells but inactive in cancer. The role of COX and Cytc phosphorylation is reviewed in a human disease context, including cancer, inflammation, sepsis, asthma, and ischemia/reperfusion injury as seen in myocardial infarction and ischemic stroke.
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Affiliation(s)
- Maik Hüttemann
- Wayne State University School of Medicine, Detroit, MI, USA.
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4
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Hüttemann M, Helling S, Sanderson TH, Sinkler C, Samavati L, Mahapatra G, Varughese A, Lu G, Liu J, Ramzan R, Vogt S, Grossman LI, Doan JW, Marcus K, Lee I. Regulation of mitochondrial respiration and apoptosis through cell signaling: cytochrome c oxidase and cytochrome c in ischemia/reperfusion injury and inflammation. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1817:598-609. [PMID: 21771582 PMCID: PMC3229836 DOI: 10.1016/j.bbabio.2011.07.001] [Citation(s) in RCA: 194] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 06/30/2011] [Accepted: 07/01/2011] [Indexed: 01/09/2023]
Abstract
Cytochrome c (Cytc) and cytochrome c oxidase (COX) catalyze the terminal reaction of the mitochondrial electron transport chain (ETC), the reduction of oxygen to water. This irreversible step is highly regulated, as indicated by the presence of tissue-specific and developmentally expressed isoforms, allosteric regulation, and reversible phosphorylations, which are found in both Cytc and COX. The crucial role of the ETC in health and disease is obvious since it, together with ATP synthase, provides the vast majority of cellular energy, which drives all cellular processes. However, under conditions of stress, the ETC generates reactive oxygen species (ROS), which cause cell damage and trigger death processes. We here discuss current knowledge of the regulation of Cytc and COX with a focus on cell signaling pathways, including cAMP/protein kinase A and tyrosine kinase signaling. Based on the crystal structures we highlight all identified phosphorylation sites on Cytc and COX, and we present a new phosphorylation site, Ser126 on COX subunit II. We conclude with a model that links cell signaling with the phosphorylation state of Cytc and COX. This in turn regulates their enzymatic activities, the mitochondrial membrane potential, and the production of ATP and ROS. Our model is discussed through two distinct human pathologies, acute inflammation as seen in sepsis, where phosphorylation leads to strong COX inhibition followed by energy depletion, and ischemia/reperfusion injury, where hyperactive ETC complexes generate pathologically high mitochondrial membrane potentials, leading to excessive ROS production. Although operating at opposite poles of the ETC activity spectrum, both conditions can lead to cell death through energy deprivation or ROS-triggered apoptosis.
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Affiliation(s)
- Maik Hüttemann
- Wayne State University School of Medicine, Detroit, MI 48201, USA.
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5
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Higgins GC, Beart PM, Nagley P. Oxidative stress triggers neuronal caspase-independent death: endonuclease G involvement in programmed cell death-type III. Cell Mol Life Sci 2009; 66:2773-87. [PMID: 19582370 PMCID: PMC11115579 DOI: 10.1007/s00018-009-0079-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 05/26/2009] [Accepted: 06/17/2009] [Indexed: 10/20/2022]
Abstract
To characterize neuronal death, primary cortical neurons (C57/Black 6 J mice) were exposed to hydrogen peroxide (H2O2) and staurosporine. Both caused cell shrinkage, nuclear condensation, DNA fragmentation and loss of plasma membrane integrity. Neither treatment induced caspase-7 activity, but caspase-3 was activated by staurosporine but not H2O2. Each treatment caused redistribution from mitochondria of both endonuclease G (Endo G) and cytochrome c. Neurons knocked down for Endo G expression using siRNA showed reduction in both nuclear condensation and DNA fragmentation after treatment with H2O2, but not staurosporine. Endo G suppression protected cells against H2O2-induced cell death, while staurosporine-induced death was merely delayed. We conclude that staurosporine induces apoptosis in these neurons, but severe oxidative stress leads to Endo G-dependent death, in the absence of caspase activation (programmed cell death-type III). Therefore, oxidative stress triggers in neurons a form of necrosis that is a systematic cellular response subject to molecular regulation.
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Affiliation(s)
- Gavin C. Higgins
- Department of Biochemistry and Molecular Biology, Monash University, Building 13D, Clayton Campus, Clayton, VIC 3800 Australia
| | - Philip M. Beart
- Florey Neuroscience Institutes and Department of Pharmacology, University of Melbourne, Parkville, VIC Australia
| | - Phillip Nagley
- Department of Biochemistry and Molecular Biology, Monash University, Building 13D, Clayton Campus, Clayton, VIC 3800 Australia
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6
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Yenari M, Kitagawa K, Lyden P, Perez-Pinzon M. Metabolic downregulation: a key to successful neuroprotection? Stroke 2008; 39:2910-7. [PMID: 18658035 DOI: 10.1161/strokeaha.108.514471] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND AND PURPOSE The search for effective neuroprotectants remains frustrating, particularly with regard to specific pharmaceuticals. However, laboratory studies have consistently shown remarkable neuroprotection with 2 nonpharmacological strategies-therapeutic hypothermia and ischemic preconditioning. Recent studies have shown that the mechanism of protection underlying both of these treatments is correlated to downregulation of cellular and tissue metabolism. Thus, understanding the mechanisms underlying such robust protective effects could lead to appropriate translation at the clinical level. In fact, hypothermia is already being used at many centers to improve neurological outcome from cardiac arrest. METHODS A systematic review of both topics is presented in terms of underlying pathophysiological mechanisms and application at the clinical level. RESULTS Although the mechanisms of protection for both therapeutic strategies are multifold, both share features of downregulating metabolism. Both therapeutic strategies are robust neuroprotectants, but translating them to the clinical arena is challenging, though not impossible, and clinical studies have shown or suggest benefits of both treatments. CONCLUSIONS The strategy of metabolic downregulation should be further explored to identify effective neuroprotectants that can be easily applied clinically.
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Affiliation(s)
- Midori Yenari
- Department of Neurology, University of California, San Francisco, San Francisco Veterans Affairs Medical Center, San , San Francisco, CA 94121, USA.
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7
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Perez-Pinzon MA. Mechanisms of neuroprotection during ischemic preconditioning: lessons from anoxic tolerance. Comp Biochem Physiol A Mol Integr Physiol 2006; 147:291-9. [PMID: 17045830 PMCID: PMC2743109 DOI: 10.1016/j.cbpa.2006.08.032] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2006] [Revised: 08/14/2006] [Accepted: 08/14/2006] [Indexed: 11/29/2022]
Abstract
Different physiological adaptations for anoxia resistance have been described in the animal kingdom. These adaptations are particularly important in organs that are highly susceptible to energy deprivation such as the heart and brain. Among vertebrates, turtles are one of the species that are highly tolerant to anoxia. In mammals however, insults such as anoxia, ischemia and hypoglycemia, all cause major histopathological events to the brain. However, in mammals even ischemic or anoxic tolerance is found when a sublethal ischemic/anoxic insult is induced sometime before a lethal ischemic/anoxic insult is induced. This phenomenon is defined as ischemic preconditioning. Better understanding of the mechanisms inducing both anoxic tolerance in turtles or ischemic preconditioning in mammals may provide novel therapeutic interventions that may aide mammalian brain to resist the ravages of cerebral ischemia. In this review, we will summarize some of the mechanisms implemented in both models of tolerance, emphasizing physiological and biochemical similarities.
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Affiliation(s)
- Miguel A Perez-Pinzon
- Cerebral Vascular Disease Research Center, Department of Neurology and Neuroscience, University of Miami Miller School of Medicine, Miami, FL 33101, USA.
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8
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Perez-Pinzon MA, Dave KR, Raval AP. Role of reactive oxygen species and protein kinase C in ischemic tolerance in the brain. Antioxid Redox Signal 2005; 7:1150-7. [PMID: 16115018 DOI: 10.1089/ars.2005.7.1150] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
It is now understood that the mechanisms leading to neuronal cell death after cerebral ischemia are highly complex. A well established fact in this field is that neurons continue to die over days and months after ischemia, and that reperfusion following cerebral ischemia contributes substantially to ischemic injury. It is now well accepted that central to ischemic/reperfusion-induced injury is what occurs to mitochondria hours to days following the ischemic insult. For many years, it has been established that reactive oxygen species (ROS) and reactive nitrogen species (RNS) promote lipid, protein, and DNA oxidation that affects normal cell physiology and eventually leads to neuronal demise. In addition to oxidation of neuronal molecules by ROS and RNS, a novel pathway for molecular modifications has risen from the concept that ROS can activate specific signal transduction pathways that, depending on the insult degree, can lead to either normal plasticity or pathology. Two examples of these pathways could explain why lethal ischemic insults lead to the translocation of protein kinase Cdelta (deltaPKC), which plays a role in apoptosis after cerebral ischemia, or why sublethal ischemic insults, such as in ischemic preconditioning, lead to the translocation of epsilonPKC, which plays a pivotal role in neuroprotection. A better understanding of the mechanisms by which ROS and/or RNS modulate key protein kinases that are involved in signaling pathways that lead to cell death and survival after cerebral ischemia will help devise novel therapeutic strategies.
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Affiliation(s)
- Miguel A Perez-Pinzon
- Cerebral Vascular Disease Research Center, Department of Neurology and Neuroscience, University of Miami Miller School of Medicine, Miami, FL 33101, USA.
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9
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Pérez-Pinzón MA. Neuroprotective effects of ischemic preconditioning in brain mitochondria following cerebral ischemia. J Bioenerg Biomembr 2005; 36:323-7. [PMID: 15377866 DOI: 10.1023/b:jobb.0000041762.47544.ff] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Numerous studies support the hypothesis that reperfusion following cerebral ischemia contributes substantially to ischemic injury and that mitochondrial dysfunction plays a central role. Defining the mechanisms by which mitochondrial dysfunction occurs may be important for the development of new therapies against delayed neuronal cell death. Ischemic preconditioning (IP) increases an organ's resistance to ischemic injury. There are two windows for IPC, one that requires several hours to develop and another one with a rapid setting (rapid window). However, the rapid window only provides neuroprotection for few days. We have recently determined that this lack of chronic protection by the rapid window was due to lack of protection against mitochondrial dysfunction.
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Affiliation(s)
- Miguel A Pérez-Pinzón
- Cerebral Vascular Disease Research Center, Department of Neurology and Neuroscience Program, University of Miami School of Medicine, Miami, Florida 33101, USA.
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10
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Ouyang YB, Giffard RG. Cellular neuroprotective mechanisms in cerebral ischemia: Bcl-2 family proteins and protection of mitochondrial function. Cell Calcium 2005; 36:303-11. [PMID: 15261486 DOI: 10.1016/j.ceca.2004.02.015] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2004] [Accepted: 02/18/2004] [Indexed: 10/26/2022]
Abstract
Mitochondria are central to brain cell response to ischemia, with critical roles in generation of ATP, production of free radicals, and regulation of apoptotic cell death. Changes in the permeability of the outer mitochondrial membrane to regulators of apoptosis can control ischemic cell death and this permeability is directly controlled by the Bcl-2 family of proteins. The Bcl-2 family regulate apoptosis by several mechanisms including affecting the formation of apoptotic protein-conducting pores in the outer mitochondrial membrane. The anti-apoptotic protein Bcl-2 improves neuron survival following various insults, and is protective even when administered after stroke onset in a rat model of focal ischemia. Despite intense study, the precise molecular mechanisms underlying protection by the anti-apoptotic members of the Bcl-2 family are not completely understood. This review focuses on the mechanisms by which Bcl-2 family members control the permeability of the mitochondrial membrane and influence other aspects of mitochondrial function after brain ischemia, concluding with discussion of the potential use of Bcl-2 for the treatment of cerebral ischemia.
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Affiliation(s)
- Yi-Bing Ouyang
- Department of Anesthesia, Stanford University School of Medicine, Grant Building S272, Stanford, CA 94305, USA
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11
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Dave KR, Saul I, Busto R, Ginsberg MD, Sick TJ, Pérez-Pinzón MA. Ischemic preconditioning preserves mitochondrial function after global cerebral ischemia in rat hippocampus. J Cereb Blood Flow Metab 2001; 21:1401-10. [PMID: 11740201 DOI: 10.1097/00004647-200112000-00004] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Ischemic tolerance in brain develops when sublethal ischemic insults occur before "lethal" cerebral ischemia. Two windows for the induction of tolerance by ischemic preconditioning (IPC) have been proposed: one that occurs within 1 hour after IPC, and another that occurs 1 or 2 days after IPC. The authors tested the hypotheses that IPC would reduce or prevent ischemia-induced mitochondrial dysfunction. IPC and ischemia were produced by bilateral carotid occlusions and systemic hypotension (50 mm Hg) for 2 and 10 minutes, respectively. Nonsynaptosomal mitochondria were harvested 24 hours after the 10-minute "test" ischemic insult. No significant changes were observed in the oxygen consumption rates and activities for hippocampal mitochondrial complexes I to IV between the IPC and sham groups. Twenty-four hours of reperfusion after 10 minutes of global ischemia (without IPC) promoted significant decreases in the oxygen consumption rates in presence of substrates for complexes I and II compared with the IPC and sham groups. These data suggest that IPC protects the integrity of mitochondrial oxidative phosphorylation after cerebral ischemia.
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Affiliation(s)
- K R Dave
- Cerebral Vascular Disease Research Center, Department of Neurology, University of Miami School of Medicine, Miami, Florida, USA
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12
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Huang WC, Chen PC, Jou SB, Cheng JT. Protein kinase C and changes in manganese superoxide dismutase gene expression in cultured glial cells. Clin Exp Pharmacol Physiol 2001; 28:822-5. [PMID: 11553022 DOI: 10.1046/j.1440-1681.2001.03529.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
1. To study the role of protein kinase C (PKC) in the increase in manganese superoxide dismutase (Mn-SOD) gene expression following transient hypoxia in glial cells, we examined the mRNA levels of Mn-SOD using northern blot analysis. 2. The Mn-SOD mRNA levels were markedly increased after exposure to nitrogen gas for 5 min. 3. Pretreatment with chelerythrine or GF109203x, inhibitors of PKC, attenuated the increase in Mn-SOD mRNA following hypoxia in a concentration-dependent manner. 4. Incubation with phorbol 12-myristate 13-acetate, the PKC activator, enhanced the increase in Mn-SOD gene expression in response to transient hypoxia. 5. The results suggest that hypoxia increases Mn-SOD gene expression in cultured glial cells mainly through activation of a PKC pathway.
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Affiliation(s)
- W C Huang
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan City, Taiwan
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13
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Sims NR, Anderson MF, Hobbs LM, Kong JY, Phillips S, Powell JA, Zaidan E. Impairment of brain mitochondrial function by hydrogen peroxide. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 2000; 77:176-84. [PMID: 10837913 DOI: 10.1016/s0169-328x(00)00049-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Hydrogen peroxide, at concentrations comparable to those observed under some pathological conditions, produced a concentration-dependent inhibition of state 3 (ADP-stimulated) and uncoupled mitochondrial respiratory activity. The ADP:O ratio was also substantially reduced. In contrast, the organic peroxide, t-butylhydroperoxide at the same concentrations produced no significant changes in respiratory activity. Intramitochondrial glutathione was oxidised to a similar extent in the presence of hydrogen peroxide or t-butylhydroperoxide. Thus, changes in this endogenous antioxidant apparently did not underlie the different responses to these peroxides. The effects of hydrogen peroxide were not altered by deferoxamine indicating that the extramitochondrial generation of hydroxyl radicals was not likely to be involved. However, modifications arising from the generation of hydroxyl radicals within the mitochondria remain a likely contributor to the observed deleterious effects on respiratory function. The inhibitory effects of hydrogen peroxide were greatest when pyruvate plus malate were present as respiratory substrates. Lesser inhibition was seen with glutamate plus malate and no significant inhibitory effects were detected in the presence of succinate. The findings suggest that mitochondrial components involved in pyruvate oxidation were particularly sensitive to the hydrogen peroxide treatment. However, no significant change was seen in activity of either the pyruvate dehydrogenase complex or NADH-ubiquinone oxidoreductase (complex I) when measured directly following treatment of the mitochondria with hydrogen peroxide.
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Affiliation(s)
- N R Sims
- Department of Medical Biochemistry and Centre for Neuroscience, School of Medicine, Flinders University, G.P.O. Box 2100, South Australia, 5001, Adelaide, Australia.
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14
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Pérez-Pinzón MA, Sick TJ, Rosenthal M. Mechanism(s) of mitochondrial hyperoxidation after global cerebral ischemia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2000; 471:175-80. [PMID: 10659145 DOI: 10.1007/978-1-4615-4717-4_21] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Affiliation(s)
- M A Pérez-Pinzón
- Department of Neurology, University of Miami School of Medicine, Florida 33101, USA
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15
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Chang YS, Park WS, Ko SY, Kang MJ, Han JM, Lee M, Choi J. Effects of fasting and insulin-induced hypoglycemia on brain cell membrane function and energy metabolism during hypoxia-ischemia in newborn piglets. Brain Res 1999; 844:135-42. [PMID: 10536269 DOI: 10.1016/s0006-8993(99)01940-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
This study was done to determine the effects of 12 h fasting-induced mild hypoglycemia (blood glucose 60 mg/dl) and insulin-induced moderate hypoglycemia (blood glucose 35 mg/dl) on brain cell membrane function and energy metabolism during hypoxia-ischemia in newborn piglets. Sixty-three ventilated piglets were divided into six groups; normoglycemic control (NC, n=8), fasting-induced mildly hypoglycemic control (FC, n=10), insulin-induced moderately hypoglycemic control (IC, n=10), normoglycemic/hypoxic-ischemic (NH, n=11), fasting-induced mildly hypoglycemic/hypoxic-ischemic (FH, n=12) and insulin-induced moderately hypoglycemic/hypoxic-ischemic (IH, n=12) group. Cerebral hypoxia-ischemia was induced by occlusion of bilateral common carotid arteries and simultaneous breathing with 8% oxygen for 30 min. The brain lactate level was elevated in NH group and this change was attenuated in FH and IH groups. The extent of cerebral lactic acidosis during hypoxic-ischemic insult showed significant positive correlation with blood glucose level (r=0.55, p<0.001). Cerebral Na+, K+-ATPase activity and concentrations of high-energy phosphate compounds were reduced in NH group and these changes were not ameliorated in FH or IH group. Cortical levels of conjugated dienes, measured as an index of lipid peroxidation of brain cell membrane, were significantly elevated in NH, FH and IH groups compared with NC, FC and IC groups and these increases were more profound in FH and IH with respect to NH. Blood glucose concentration showed significant inverse correlation with levels of conjugated dienes (r=-0.35, p<0.05). These findings suggest that, unlike in adults, mild or moderate hypoglycemia, regardless of methods of induction such as fasting or insulin-induced, during cerebral hypoxia-ischemia is not beneficial and may even be harmful in neonates.
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Affiliation(s)
- Y S Chang
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 ILWON-dong, Kangnam-ku, Seoul, South Korea
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16
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Oxygen/glucose deprivation in hippocampal slices: altered intraneuronal elemental composition predicts structural and functional damage. J Neurosci 1999. [PMID: 9880582 DOI: 10.1523/jneurosci.19-02-00619.1999] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Effects of oxygen/glucose deprivation (OGD) on subcellular elemental composition and water content were determined in nerve cell bodies from CA1 areas of rat hippocampal slices. Electron probe x-ray microanalysis was used to measure percentage water and concentrations of Na, P, K, Cl, Mg, and Ca in cytoplasm, nucleus, and mitochondria of cells exposed to normal and oxygen/glucose deficient medium. As an early (2 min) consequence of OGD, evoked synaptic potentials were lost, and K, Cl, P, and Mg concentrations decreased significantly in all morphological compartments. As exposure to in vitro OGD continued, a negative DC shift in interstitial voltage occurred ( approximately 5 min), whereas general elemental disruption worsened in cytoplasm and nucleus (5-42 min). Similar elemental changes were noted in mitochondria, except that Ca levels increased during the first 5 min of OGD and then decreased over the remaining experimental period (12-42 min). Compartmental water content decreased early (2 min), returned to control after 12 min of OGD, and then exceeded control levels at 42 min. After OGD (12 min), perfusion of hippocampal slices with control oxygenated solutions (reoxygenation) for 30 min did not restore synaptic function or improve disrupted elemental composition. Notably, reoxygenated CA1 cell compartments exhibited significantly elevated Ca levels relative to those associated with 42 min of OGD. When slices were incubated at 31 degreesC (hypothermia) during OGD/reoxygenation, neuronal dysfunction and elemental deregulation were minimal. Results show that in vitro OGD causes loss of transmembrane Na, K, and Ca gradients in CA1 neurons of hippocampal slices and that hypothermia can obtund this damaging process and preserve neuronal function.
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17
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Pérez-Pinzón MA, Xu GP, Born J, Lorenzo J, Busto R, Rosenthal M, Sick TJ. Cytochrome C is released from mitochondria into the cytosol after cerebral anoxia or ischemia. J Cereb Blood Flow Metab 1999; 19:39-43. [PMID: 9886353 DOI: 10.1097/00004647-199901000-00004] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Mitochondrial dysfunction may underlie both acute and delayed neuronal cell death resulting from cerebral ischemia. Specifically, postischemic release of mitochondrial constituents such as the pro-apoptotic respiratory chain component cytochrome c could contribute acutely to further mitochondrial dysfunction and to promote delayed neuronal death. Experiments reported here tested the hypothesis that ischemia or severe hypoxia results in release of cytochrome c from mitochondria. Cytochrome c was measured spectrophotometrically from either the cytosolic fraction of cortical brain homogenates after global ischemia plus reperfusion, or from brain slices subjected to severe hypoxia plus reoxygenation. Cytochrome c content in cytosol derived from cerebral cortex was increased after ischemia and reperfusion. In intact hippocampal slices, there was a loss of reducible cytochrome c after hypoxia/ reoxygenation, which is consistent with a decrease of this redox carrier in the mitochondrial pool. These results suggest that cytochrome c is lost to the cytosol after cerebral ischemia in a manner that may contribute to postischemic mitochondrial dysfunction and to delayed neuronal death.
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Affiliation(s)
- M A Pérez-Pinzón
- Department of Neurology, University of Miami School of Medicine, Florida 33101, USA
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18
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Niu CS, Chang CK, Lin LS, Jou SB, Kuo DH, Liao SS, Cheng JT. Modification of superoxide dismutase (SOD) mRNA and activity by a transient hypoxic stress in cultured glial cells. Neurosci Lett 1998; 251:145-8. [PMID: 9726364 DOI: 10.1016/s0304-3940(98)00506-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In order to understand the role of superoxide dismutase (SOD) in response to transient hypoxia or hypoxia-reperfusion in astrocytes, the present study performed an in vitro investigation using rat glial cells in culture. Hypoxia was induced by an incubation with nitrogen gas for 10 min and that followed a further reperfusion with air for 10 min was indicating as hypoxia-normoxia. Activity of SOD was determined by the reduction of nitroblue tetrazolium (NTB). Changes of mRNA for Cu,Zn-SOD or Mn-SOD were also characterized using Northern blotting analysis. Transient hypoxia increased the activity of Mn-SOD but not that of Cu,Zn-SOD in glial cells. Expression of mRNA for SOD was also elevated in cells received hypoxia and the mRNA level for Mn-SOD raised higher than that for Cu,Zn-SOD. In cells received hypoxia-reperfusion, these changes of SOD both the activity and the mRNA level were not observed. Otherwise, the SOD protein amount, both Cu,Zn-SOD and Mn-SOD, identified by Western blotting was not changed in glial cells receiving hypoxic stress or not. The obtained results suggest that gene expression and activity of Mn-SOD in glial cells can be activated in response to the transient hypoxic stress.
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Affiliation(s)
- C S Niu
- Department of Pharmacology, Tzu-Chi Junior College of Nursing, Hualien, Taiwan
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19
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Higuchi T, Graham SH, Fernandez EJ, Rooney WD, Gaspary HL, Weiner MW, Maudsley AA. Effects of severe global ischemia on N-acetylaspartate and other metabolites in the rat brain. Magn Reson Med 1997; 37:851-7. [PMID: 9178235 PMCID: PMC2744638 DOI: 10.1002/mrm.1910370608] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
N-acetylaspartate (NAA) is found exclusively in neurons and their processes in the adult brain. Since the regional distribution of NAA may be imaged using magnetic resonance spectroscopic imaging (1H-MRSI), a regional measure of neuronal density may be noninvasively obtained. The technique may be particularly useful in the diagnosis of diseases where neurons are selectively injured, since these diseases do not result in definitive changes on conventional imaging studies. The goal of this study was to determine whether 1H-MRSI measurement of NAA defects neuronal loss following global ischemia. 1H-MRSI was performed in rats 24 h after global ischemia was induced by bilateral carotid occlusion plus hypotension. 1-H-MRSI showed that NAA was decreased by 28-74% in vulnerable regions, including the cortex, striatum, hippocampus, and, to a lesser extent, the thalamus. No change was observed in the brain stem or cerebellum. Regions where 1H-MRSI observed NAA was decreased also had histological evidence of selective neuronal necrosis and showed marked increase of lactate and alanine. These results show that 1H-MRSI detected loss of NAA in brain regions with selective neuronal loss, suggesting that 1H-MRSI measurements of NAA could detect neuronal loss in a variety of disease states where there is selective neuronal necrosis.
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Affiliation(s)
- T Higuchi
- Department of Radiology, University of California San Francisco, USA
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20
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Pérez-Pinzón MA, Mumford PL, Rosenthal M, Sick TJ. Antioxidants, mitochondrial hyperoxidation and electrical recovery after anoxia in hippocampal slices. Brain Res 1997; 754:163-70. [PMID: 9134972 DOI: 10.1016/s0006-8993(97)00066-8] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Cerebral injury may occur not only during brain ischemia but also during reperfusion afterward. A characteristic event during reperfusion after cerebral ischemia, or reoxygenation after anoxia in hippocampal slices, is hyperoxidation of the electron carriers of the mitochondrial respiratory chain. Earlier studies suggested that mitochondrial hyperoxidation was produced by an oxyradical mechanism and was linked to neuronal damage. Present studies sought to test this hypothesis by determining whether antioxidants could suppress mitochondrial hyperoxidation and improve electrical recovery after anoxia in hippocampal slices. Both 500 microM ascorbate and 50 microM glutathione decreased post-anoxic hyperoxidation of NADH and improved electrical recovery in hippocampal slices. These data support a role of oxygen free radicals in promoting post-anoxic mitochondrial hyperoxidation and electrical failure, and suggest that these effects of anoxia or ischemia may be linked.
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Affiliation(s)
- M A Pérez-Pinzón
- Department of Neurology, University of Miami School of Medicine, FL 33177, USA.
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21
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Kuroda S, Siesjö P, Siesjö BK. Focal Cerebral Ischemia. YEARBOOK OF INTENSIVE CARE AND EMERGENCY MEDICINE 1997. [DOI: 10.1007/978-3-662-13450-4_60] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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22
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Tymianski M, Tator CH. Normal and abnormal calcium homeostasis in neurons: a basis for the pathophysiology of traumatic and ischemic central nervous system injury. Neurosurgery 1996; 38:1176-95. [PMID: 8727150 DOI: 10.1097/00006123-199606000-00028] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Clinical recovery after central nervous system (CNS) trauma or ischemia may be limited by a neural injury process that is triggered and perpetuated at the cellular level, rather than by a lesion amenable to surgical repair. It is widely thought that one such process, a fundamental pathological mechanism initiated by CNS injury, is a disruption of cellular Ca2+ homeostasis. Because of the critical role of Ca2+ ions in regulating innumerable cellular functions, this major homeostatic disturbance is thought to trigger neuronal and axonal degeneration and produce clinical disability. We review those aspects of normal and pathological Ca2+ homeostasis in neurons that relate to neurodegeneration and to the application of neuroprotective strategies for the treatment of CNS injury. In particular, we examine the contribution of Ca(2+)-permeable ionic channels, Ca2+ pumps, intracellular Ca2+ stores, intracellular Ca2+ buffering systems, and the roles of secondary, Ca(2+)-dependent processes in neurodegeneration. A number of hypotheses linking Ca2+ ions and Ca2+ permeable channels to neurotoxicity are discussed with an emphasis on strategies for lessening Ca(2+)-related damage. A number of these strategies may have a future role in the treatment of traumatic and ischemic CNS injury.
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Affiliation(s)
- M Tymianski
- Division of Neurosurgery, Toronto Hospital, Ontario, Canada
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23
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Tymianski M, Tator CH. Normal and Abnormal Calcium Homeostasis in Neurons: A Basis for the Pathophysiology of Traumatic and Ischemic Central Nervous System Injury. Neurosurgery 1996. [DOI: 10.1227/00006123-199606000-00028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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24
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Siesjö BK, Katsura KI, Kristián T, Li PA, Siesjö P. Molecular mechanisms of acidosis-mediated damage. ACTA NEUROCHIRURGICA. SUPPLEMENT 1996; 66:8-14. [PMID: 8780790 DOI: 10.1007/978-3-7091-9465-2_2] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The present article is concerned with mechanisms which are responsible for the exaggerated brain damage observed in hyperglycemic animals subjected to transient global or forebrain ischemia. Since hyperglycemia enchances the production of lactate plus H+ during ischemia, it seems likely that aggravation of damage is due to exaggerated intra- and extracellular acidosis. This contention is supported by results showing a detrimental effect of extreme hypercapnia in normoglycemic rats subjected to transient ischemia or to hypoglycemic coma. Enhanced acidosis may exaggerate ischemic damage by one of three mechanisms: (i) accelerating free radical production via H(+)-dependent reactions, some of which are catalyzed by iron released from protein bindings by a lowering of pH, (ii) by perturbing the intracellular signal transduction pathway, leading to changes in gene expression or protein synthesis, or (iii) by activating endonucleases which cause DNA fragmentation. While activation of endonucleases must affect the nucleus, the targets of free radical attack are not known. Microvessels are considered likely targets of such attack in sustained ischemia and in trauma; however, enhanced acidosis is not known to aggravate microvascular dysfunction, or to induce inflammatory responses at the endothelial-blood interface. A more likely target is the mitochondrion. Thus, if the ischemia is of long duration (30 min) hyperglycemia triggers rapidly developing mitochondrial failure. It is speculated that this is because free radicals damage components of the respiratory chain, leading to a secondary deterioration of oxidative phosphorylation.
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Affiliation(s)
- B K Siesjö
- Laboratory for Experimental Brain Research, University of Lund, Sweden
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25
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Vlessis AA, Goldman RK, Trunkey DD. New concepts in the pathophysiology of oxygen metabolism during sepsis. Br J Surg 1995; 82:870-6. [PMID: 7648095 DOI: 10.1002/bjs.1800820705] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Sepsis is an intriguing pathological condition associated with many complex metabolic and physiological alterations. In this review a novel hypothesis in the pathophysiology of oxygen metabolism during sepsis is explored. It is proposed that the hypermetabolic response to sepsis results from enhanced reactive oxygen generation by phagocytes. Reactive oxygen detoxification by host enzyme systems subsequently leads to alterations in oxidative metabolism. The similarities between the metabolic consequences of reactive oxygen metabolism and the metabolic changes observed during sepsis are outlined. A unified concept is presented to help explain the pathophysiological changes in oxygen metabolism during sepsis.
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Affiliation(s)
- A A Vlessis
- Department of Surgery, Oregon Health Sciences University, Portland, USA
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26
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Sims NR, Zaidan E. Biochemical changes associated with selective neuronal death following short-term cerebral ischaemia. Int J Biochem Cell Biol 1995; 27:531-50. [PMID: 7671133 DOI: 10.1016/1357-2725(95)00026-l] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A brief interruption of blood flow to the brain results in the selective loss of specific subpopulations of neurons. Important advances have been made in recent years in defining the biochemical changes associated with cerebral ischaemia and reperfusion and in identifying physical and chemical interventions capable of modifying the extent of neuronal loss. Neuronal death is not irreversibly determined by the ischaemic period but develops during recirculation over a period of hours or even days in different susceptible neuronal populations. The onset of ischaemia produces a rapid decline in ATP production and an associated major redistribution of ions across the plasma membrane including a large intracellular accumulation of Ca2+ in many neurons. Alterations subsequently develop in many other metabolites. These include a marked and progressive release of neurotransmitters and a rapid accumulation of free fatty acids. Most of these alterations are reversed within the first 20 min to 1 hr of recirculation. The changes essential for initiating damage in neurons destined to die have not been definitively identified although there is some evidence suggesting roles for the intracellular Ca2+ accumulation, the release of the neurotransmitter glutamate and a brief burst of free radical production which occurs during early recirculation. During further recirculation, there are reductions in oxidative glucose metabolism and protein synthesis in many brain regions. Few changes have been detected which distinguish tissue containing ischaemia-susceptible neurons from ischaemia-resistant regions until the development of advanced degeneration and neuronal loss. Subtle changes in cytoplasmic Ca2+ content and a decrease in the respiratory capacity of mitochondria are two changes apparently selectively affecting ischaemia-susceptible regions which could contribute to neuronal loss. The mitochondrial change may be one indicator of a slowly developing post-ischaemic increase in susceptibility to oxidative damage in some cells.
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Affiliation(s)
- N R Sims
- Department of Medical Biochemistry, Flinders University of South Australia, Adelaide
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27
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Musleh W, Bruce A, Malfroy B, Baudry M. Effects of EUK-8, a synthetic catalytic superoxide scavenger, on hypoxia- and acidosis-induced damage in hippocampal slices. Neuropharmacology 1994; 33:929-34. [PMID: 7969813 DOI: 10.1016/0028-3908(94)90191-0] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Anoxia produces deleterious effects on synaptic transmission in the hippocampal slice preparation. A proposed source of damage is the superoxide radical (.O2-) produced during the earlier period of reoxygenation. The present study tested the effects of a synthetic, catalytic superoxide radical scavenger (EUK-8) on CA1 pyramidal cell responses elicited by electrical stimulation of the Schaffer-commissural pathway after severe anoxic episodes. Following reoxygenation, slices incubated with EUK-8 (50 microM) exhibited significantly better recovery of excitatory postsynaptic potentials (EPSPs) than control slices. In addition, repeated episodes of anoxia produced irreversible loss of synaptic transmission in the majority of control slices (93 +/- 7%, n = 15), compared to a small fraction in EUK-8-incubated slices (27 +/- 12%, n = 15). A thiobarbituric acid (TBA) test was used to assess the effect of EUK-8 on lipid peroxidation elicited in hippocampal slices by acidosis and lactic acid (pH 5.0 and 30 mM lactic acid). Incubation in the presence of EUK-8 totally prevented the increase in lipid peroxidation produced by acidosis and lactic acid in both the incubation medium and the slice homogenates. These results indicate that a superoxide scavenger like EUK-8 prevents damage produced by acidosis and anoxia in hippocampal slices and suggest the possibility of using this type of molecule under various pathological conditions.
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Affiliation(s)
- W Musleh
- Neuroscience Program, University of Southern California, Los Angeles 90089-2520
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28
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Copin JC, Ledig M, Tholey G. Almitrine prevents some hypoxia-induced metabolic injury in rat astrocytes. MOLECULAR AND CHEMICAL NEUROPATHOLOGY 1993; 20:97-109. [PMID: 7905267 DOI: 10.1007/bf02815365] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
During reperfusion of ischemic brain tissue, the production of reactive oxygen species initiates several modifications of the astroglial functional and ultrastructural integrity. During 24 h after ischemic treatment, modification of cellular superoxide free radical scavenging systems have been observed in primary culture of rat astroglial cell. Mitochondrial Mn superoxide dismutase activity (Mn-SOD) gradually decreases, whereas that of the cytosolic Cu,Zn form of the enzyme remains unaffected. We observed in parallel a significant decrease of glutamine synthetase (GS), an astrocyte specifically located enzyme. Addition of almitrine (dialylamine-4',6'-triazinyl 2')-1-(bis-parafluoro-benzydryl)-4-piperazine or dibucaine (a phospholipase A2 inhibitor) antagonizes the decrease of Mn-SOD activity, but does not affect modification of GS activity. Combined effects are observed by simultaneous addition of both drugs. Our data demonstrate that almitrine may increase the synthesis of some mitochondrial proteins, like Mn-SOD, and provide support for further study on the therapeutic potential of almitrine in ischemic astroglial cell injury.
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Affiliation(s)
- J C Copin
- Laboratoire de Neurobiologie Ontogenique, Centre de Neurochimie du CNRS, Strasbourg, France
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29
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Abstract
Excitotoxicity and oxidative stress are two phenomena that have been repeatedly described as being implicated in a wide range of disorders of the nervous system. Such disorders include several common idiopathic neurological diseases, traumatic brain injury, and the consequences of exposure to certain neurotoxic agents. While there is evidence that metabolic derangements can lead to these adverse processes, and that these processes may synergize in their damaging effects, the degree of interdependence, and the causal relation between them is not clear. The intent of this review is to delineate potential mechanisms which may unit hyperexcitation to the excessive generation of reactive oxygen species. The degree of linkage between these events appears rather strong. It is likely that excitoxicity frequently leads to a pro-oxidant condition but that high rates of these events appears rather strong. It is likely that excitoxicity frequently leads to a pro-oxidant condition but that high rates of generation of reactive oxygen species are not invariably accompanied by a hyperexcited neuronal state Both excitoxic and 'oxidotoxic' states result from the failure of normal compensatory antiexcitatory and antioxidant mechanisms to maintain cellular homeostasis.
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Affiliation(s)
- S C Bondy
- Department of Community and Environmental Medicine, University of California, Irvine 92717-1825
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30
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Copin JC, Ledig M, Tholey G. Free radical scavenging systems of rat astroglial cells in primary culture: effects of anoxia and drug treatment. Neurochem Res 1992; 17:677-82. [PMID: 1407263 DOI: 10.1007/bf00968004] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Hypoxic injury of rat astroglial cells in primary culture initiates several modifications of their functional integrity. A significant decrease of the cellular oxygen consumption was observed in astrocytes submitted to a 15 h low oxygen pressure. The addition of almitrine (dialylamino-4',6'-triazinyl 2')-1-(bis-parafluorobenzydryl)-4-piperazine, a chemoreceptor agonist, restored almost completely the respiratory activity of the hypoxia treated cells. In order to test the hypothesis that oxygen free radical formation may contribute to the cellular damage resulting from ischemia, the activities of the following antioxidant enzymatic systems have been determined in the cultured astrocytes: Cu,Zn- and Mn-superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), glutathione reductase (GSH-RED), and catalase (CAT). Only a significant and specific decrease of the Mn-SOD activity was observed after the hypoxia-normoxia exposure. The other oxygen radical scavenging systems were not modified. The addition of almitrine antagonized the decrease of the Mn-SOD activity observed in the low oxygen pressure treated cells, but results clearly point-out the importance of oxygen radical production in the astroglial response after hypoxic injury. A beneficial effect of almitrine toward the observed alteration has been underlined. It is suggested that some mitochondrial alterations could be related to some aspects of the astroglial hypoxic stress.
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Affiliation(s)
- J C Copin
- Laboratoire de Neurobiologie Ontogénique, Centre de Neurochimie du CNRS, Strasbourg, France
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31
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32
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Abstract
The inherent biochemical, anatomical and physiological characteristics of the brain make it especially vulnerable to insult. Specifically, some of these characteristics such as myelin and a high energy requirement provide for the introduction of free radical-induced insult. Recently, the biochemistry of free radicals has received considerable attention. It also has become increasingly apparent that many drug and chemical-induced toxicities may be evoked via free radicals and oxidative stress. Major points addressed in this work are the regulation of neural free radical generation by antioxidants and protective enzymes, xenobiotic-induced disruption of cerebral redox status, and specific examples of neurotoxic agent-induced alterations in free radical production as measured by the fluorescent probe dichlorofluorescein. This article considers the thesis that free radical mechanisms may contribute significantly to the properties of several diverse neurotoxic agents and proposes that excess production of free radicals may be common phenomena of neurotoxicity.
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Affiliation(s)
- C P LeBel
- Arthur D. Little, Inc., Toxicology Unit, Cambridge, MA 02140
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33
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Eleff SM, Maruki Y, Monsein LH, Traystman RJ, Bryan RN, Koehler RC. Sodium, ATP, and intracellular pH transients during reversible complete ischemia of dog cerebrum. Stroke 1991; 22:233-41. [PMID: 2003287 DOI: 10.1161/01.str.22.2.233] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We tested the hypotheses that with the onset of cerebral ischemia, massive cellular sodium influx does not occur until adenosine triphosphate is fully depleted and that on reperfusion, neuronal sodium efflux does not occur until adenosine triphosphate is fully restored. We examined the temporal relationships among transcellular sodium, energy metabolism, and intracellular pH with sodium and phosphorus magnetic resonance spectroscopy in a new, hemodynamically stable, brain stem-sparing model of reversible, complete cerebral ischemia in eight anesthetized dogs. Inflation of a neck tourniquet after placement of glue at the tip of the basilar artery resulted in decreased blood flow to the cerebrum from 29 +/- 5 to 0.3 +/- 0.5 ml/min/100 g. Medullary blood flow was not significantly affected, and arterial blood pressure was unchanged. Sodium signal intensity decreased and did not lag behind the fall in adenosine triphosphate. After 12 minutes of ischemia, reperfusion resulted in a more rapid recovery of sodium intensity (12.4 +/- 4.8 minutes) than either adenosine triphosphate (16.5 +/- 3.7 minutes) or intracellular pH (38.9 +/- 1.8 minutes). Because intracellular sodium has a weaker signal than extracellular sodium, the decreased sodium intensity is interpreted as sodium influx and indicates that sodium influx does not require full depletion of adenosine triphosphate. Rapid recovery of sodium intensity during early reperfusion may represent sodium efflux, although increased plasma volume and sodium uptake from plasma may also contribute. If our interpretation of the sodium signal is correct, delayed recovery of adenosine triphosphate may be due to the utilization of adenosine triphosphate for the restoration of transcellular sodium gradient.
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Affiliation(s)
- S M Eleff
- Department of Anesthesiology, Johns Hopkins Medical Institutions, Baltimore, Md
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34
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Vlessis AA, Bartos D, Trunkey D. Importance of spontaneous alpha-ketoacid decarboxylation in experiments involving peroxide. Biochem Biophys Res Commun 1990; 170:1281-7. [PMID: 2390093 DOI: 10.1016/0006-291x(90)90532-r] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The potential role of spontaneous alpha-ketoacid decarboxylation as a source of interference in experiments involving peroxide was investigated. The assay of pyruvate dehydrogenase activity in isolated renal mitochondria was employed as an example. Spontaneous peroxide-induced pyruvate decarboxylation competed significantly with enzymatic decarboxylation at peroxide concentrations greater than 50 microM. Corrected values for enzymatic decarboxylation could be obtained by subtracting spontaneous decarboxylation rates from rates obtained in the presence of mitochondria. At higher peroxide concentrations (greater than 200 microM), reaction product accumulates (acetoacetate) to levels which may have regulatory effects on mitochondrial metabolism. The divalent cations, Ca2+ and Mg2+, both accelerate spontaneous peroxide-induced pyruvate decarboxylation while other components of the assay medium had an inhibitory effect on the reaction. The results are discussed in relation to the currently accepted reaction mechanism. Investigators who perform experiments involving reactive oxygen species should be familiar with this often overlooked reaction.
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Affiliation(s)
- A A Vlessis
- Department of Surgery, Oregon Health Sciences University, Portland, Oregon
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