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Danielski LG, Giustina AD, Gava FF, Barichello T, Petronilho F. The Many Faces of Astrocytes in the Septic Brain. Mol Neurobiol 2022; 59:7229-7235. [PMID: 36136265 DOI: 10.1007/s12035-022-03027-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 08/31/2022] [Indexed: 10/14/2022]
Abstract
Sepsis is a life-threatening organ dysfunction that is caused by a dysregulated host response to infection. Surviving patients have cognitive and memory damage that started during sepsis. These neurologic damages have been associated with increased BBB permeability and microglial activation. However, a few discrete studies have seen over the years pointing to the potential role of astrocytes in the pathophysiology of neurological damage after sepsis. The purpose of this article is to review information on the potential role of astrocytes during sepsis, as well as to provoke further studies in this area. These published articles show astrocytic activation after sepsis; they also evidence the release of inflammatory mediators by these cells. In this sense, the role of astrocytes should be better elucidated during sepsis progression.
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Affiliation(s)
- Lucinéia Gainski Danielski
- Laboratory of Neurobiology of Inflammatory and Metabolic Processes, Graduate Program in Health Sciences, Health Sciences Unit, University of South Santa Catarina, Tubarao, SC, Brazil.,Laboratory of Experimental Neurology, Graduate Program in Health Sciences, Health Sciences Unit, University of Southern Santa Catarina, Criciuma, SC, Brazil
| | - Amanda Della Giustina
- School of Nutrition Sciences, Faculty of Health Sciences, University of Ottawa, Ottawa, Canada
| | - Fernanda Frederico Gava
- Laboratory of Experimental Neurology, Graduate Program in Health Sciences, Health Sciences Unit, University of Southern Santa Catarina, Criciuma, SC, Brazil
| | - Tatiana Barichello
- Laboratory of Experimental Pathophysiology, Graduate Program in Health Sciences, Health Sciences Unit, University of Southern Santa Catarina, Criciuma, SC, Brazil.,Faillace Department of Psychiatry and Behavioral Sciences, McGovern Medical School, Translational Psychiatry Program, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, 77054, USA
| | - Fabricia Petronilho
- Laboratory of Experimental Neurology, Graduate Program in Health Sciences, Health Sciences Unit, University of Southern Santa Catarina, Criciuma, SC, Brazil.
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2
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Pathogenesis of sepsis-associated encephalopathy: more than blood-brain barrier dysfunction. Mol Biol Rep 2022; 49:10091-10099. [PMID: 35639274 DOI: 10.1007/s11033-022-07592-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 05/11/2022] [Indexed: 12/19/2022]
Abstract
Sepsis-associated encephalopathy is a common neurological complication of sepsis and is responsible for higher mortality and poorer long-term outcomes in septic patients. Sepsis-associated encephalopathy symptoms can range from mild delirium to deep coma, which occurs in up to 70% of patients in intensive care units. The pathological changes in the brain associated with sepsis include cerebral ischaemia, cerebral haemorrhage, abscess and progressive multifocal necrotic leukoencephalopathy. Several mechanisms are involved in the pathogenesis of sepsis-associated encephalopathy, such as blood-brain barrier dysfunction, cerebral blood flow impairment, glial cell activation, leukocyte transmigration, and neurotransmitter disturbances. These events are interrelated and influence each other, therefore they do not act as independent factors. This review is focused on new evidence showing the pathological process of sepsis-associated encephalopathy.
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3
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Barbosa-Silva MC, Lima MN, Battaglini D, Robba C, Pelosi P, Rocco PRM, Maron-Gutierrez T. Infectious disease-associated encephalopathies. Crit Care 2021; 25:236. [PMID: 34229735 PMCID: PMC8259088 DOI: 10.1186/s13054-021-03659-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 06/28/2021] [Indexed: 02/07/2023] Open
Abstract
Infectious diseases may affect brain function and cause encephalopathy even when the pathogen does not directly infect the central nervous system, known as infectious disease-associated encephalopathy. The systemic inflammatory process may result in neuroinflammation, with glial cell activation and increased levels of cytokines, reduced neurotrophic factors, blood-brain barrier dysfunction, neurotransmitter metabolism imbalances, and neurotoxicity, and behavioral and cognitive impairments often occur in the late course. Even though infectious disease-associated encephalopathies may cause devastating neurologic and cognitive deficits, the concept of infectious disease-associated encephalopathies is still under-investigated; knowledge of the underlying mechanisms, which may be distinct from those of encephalopathies of non-infectious cause, is still limited. In this review, we focus on the pathophysiology of encephalopathies associated with peripheral (sepsis, malaria, influenza, and COVID-19), emerging therapeutic strategies, and the role of neuroinflammation.
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Affiliation(s)
- Maria C Barbosa-Silva
- Laboratory of Immunopharmacology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Fiocruz, Av. Brasil, 4365, Pavilhão 108, sala 45, Manguinhos, Rio de Janeiro, RJ, 21040-360, Brazil
| | - Maiara N Lima
- Laboratory of Immunopharmacology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Fiocruz, Av. Brasil, 4365, Pavilhão 108, sala 45, Manguinhos, Rio de Janeiro, RJ, 21040-360, Brazil
| | - Denise Battaglini
- Anesthesia and Intensive Care, San Martino Policlinico Hospital, IRCCS for Oncology and Neuroscience, Genoa, Italy
| | - Chiara Robba
- Anesthesia and Intensive Care, San Martino Policlinico Hospital, IRCCS for Oncology and Neuroscience, Genoa, Italy
- Department of Surgical Sciences and Integrated Diagnostics (DISC), University of Genoa, Genoa, Italy
| | - Paolo Pelosi
- Anesthesia and Intensive Care, San Martino Policlinico Hospital, IRCCS for Oncology and Neuroscience, Genoa, Italy
- Department of Surgical Sciences and Integrated Diagnostics (DISC), University of Genoa, Genoa, Italy
| | - Patricia R M Rocco
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- National Institute of Science and Technology for Regenerative Medicine, Rio de Janeiro, Rio de Janeiro, Brazil
- Rio de Janeiro Network on Neuroinflammation, Carlos Chagas Filho Foundation for Supporting Research in the State of Rio de Janeiro (FAPERJ), Rio de Janeiro, Brazil
| | - Tatiana Maron-Gutierrez
- Laboratory of Immunopharmacology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Fiocruz, Av. Brasil, 4365, Pavilhão 108, sala 45, Manguinhos, Rio de Janeiro, RJ, 21040-360, Brazil.
- Rio de Janeiro Network on Neuroinflammation, Carlos Chagas Filho Foundation for Supporting Research in the State of Rio de Janeiro (FAPERJ), Rio de Janeiro, Brazil.
- National Institute of Science and Technology on Neuroimmunomodulation, Rio de Janeiro, Rio de Janeiro, Brazil.
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4
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Chen Y, Qin C, Huang J, Tang X, Liu C, Huang K, Xu J, Guo G, Tong A, Zhou L. The role of astrocytes in oxidative stress of central nervous system: A mixed blessing. Cell Prolif 2020; 53:e12781. [PMID: 32035016 PMCID: PMC7106951 DOI: 10.1111/cpr.12781] [Citation(s) in RCA: 141] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Revised: 12/17/2019] [Accepted: 01/20/2020] [Indexed: 02/05/2023] Open
Abstract
Central nervous system (CNS) maintains a high level of metabolism, which leads to the generation of large amounts of free radicals, and it is also one of the most vulnerable organs to oxidative stress. Emerging evidences have shown that, as the key homeostatic cells in CNS, astrocytes are deeply involved in multiple aspects of CNS function including oxidative stress regulation. Besides, the redox level in CNS can in turn affect astrocytes in morphology and function. The complex and multiple roles of astrocytes indicate that their correct performance is crucial for the normal functioning of the CNS, and its dysfunction may result in the occurrence and progression of various neurological disorders. To date, the influence of astrocytes in CNS oxidative stress is rarely reviewed. Therefore, in this review we sum up the roles of astrocytes in redox regulation and the corresponding mechanisms under both normal and different pathological conditions.
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Affiliation(s)
- Yaxing Chen
- Department of Neurosurgery, West China Medical School, West China Hospital, Sichuan University, Chengdu, China
| | - Chen Qin
- Department of Neurosurgery, West China Medical School, West China Hospital, Sichuan University, Chengdu, China
| | - Jianhan Huang
- Department of Neurosurgery, West China Medical School, West China Hospital, Sichuan University, Chengdu, China
| | - Xin Tang
- Department of Neurosurgery, West China Medical School, West China Hospital, Sichuan University, Chengdu, China
| | - Chang Liu
- Department of Neurosurgery, West China Medical School, West China Hospital, Sichuan University, Chengdu, China
| | - Keru Huang
- Department of Neurosurgery, West China Medical School, West China Hospital, Sichuan University, Chengdu, China
| | - Jianguo Xu
- Department of Neurosurgery, West China Medical School, West China Hospital, Sichuan University, Chengdu, China
| | - Gang Guo
- State Key Laboratory of Biotherapy, West China Medical School, Sichuan University, Chengdu, China
| | - Aiping Tong
- State Key Laboratory of Biotherapy, West China Medical School, Sichuan University, Chengdu, China
| | - Liangxue Zhou
- Department of Neurosurgery, West China Medical School, West China Hospital, Sichuan University, Chengdu, China
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Heming N, Mazeraud A, Verdonk F, Bozza FA, Chrétien F, Sharshar T. Neuroanatomy of sepsis-associated encephalopathy. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2017; 21:65. [PMID: 28320461 PMCID: PMC5360026 DOI: 10.1186/s13054-017-1643-z] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2017. Other selected articles can be found online at http://ccforum.com/series/annualupdate2017. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901. Originally published in the Annual Update in Intensive Care and Emergency Medicine 2017. The number of authors differs in the two versions due to constraints regarding the number of authors in the Annual Update in Intensive Care and Emergency Medicine. In the Annual Update version of the review, the three senior authors appear in the acknowledgement section. In the Critical Care version, these three senior authors appear as full authors of the manuscript. All authors helped draft and revise the manuscript for critical intellectual content.
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Affiliation(s)
- Nicholas Heming
- Assistance Publique Hôpitaux de Paris AP-HP, Réanimation Médicale, Hôpital Raymond Poincaré, 104 boulevard Raymond-Poincaré, 92380, Garches, France.
| | - Aurelien Mazeraud
- Human Histopathology and Animal Models Institut Pasteur, 75015, Paris, France
| | - Franck Verdonk
- Human Histopathology and Animal Models Institut Pasteur, 75015, Paris, France
| | - Fernando A Bozza
- Evandro Chagas National Institute of Infectious Diseases, Fiocruz, Rio de Janeiro, Brazil
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6
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Mazeraud A, Pascal Q, Verdonk F, Heming N, Chrétien F, Sharshar T. Neuroanatomy and Physiology of Brain Dysfunction in Sepsis. Clin Chest Med 2017; 37:333-45. [PMID: 27229649 DOI: 10.1016/j.ccm.2016.01.013] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Sepsis-associated encephalopathy (SAE), a complication of sepsis, is often complicated by acute and long-term brain dysfunction. SAE is associated with electroencephalogram pattern changes and abnormal neuroimaging findings. The major processes involved are neuroinflammation, circulatory dysfunction, and excitotoxicity. Neuroinflammation and microcirculatory alterations are diffuse, whereas excitotoxicity might occur in more specific structures involved in the response to stress and the control of vital functions. A dysfunction of the brainstem, amygdala, and hippocampus might account for the increased mortality, psychological disorders, and cognitive impairment. This review summarizes clinical and paraclinical features of SAE and describes its mechanisms at cellular and structural levels.
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Affiliation(s)
- Aurelien Mazeraud
- Institut Pasteur - Unité Histopathologie Humaine et Modèles Animaux, Département Infection et Épidémiologie, Rue du docteur roux, Paris 75724 Cedex 15, France; Sorbonne Paris Cité, Paris Descartes University, Rue de l'école de médecine, Paris 75006, France; General Intensive Care, Assistance Publique Hopitaux de Paris, Raymond Poincaré Teaching Hosptal, Garches 92380, France
| | - Quentin Pascal
- Institut Pasteur - Unité Histopathologie Humaine et Modèles Animaux, Département Infection et Épidémiologie, Rue du docteur roux, Paris 75724 Cedex 15, France
| | - Franck Verdonk
- Institut Pasteur - Unité Histopathologie Humaine et Modèles Animaux, Département Infection et Épidémiologie, Rue du docteur roux, Paris 75724 Cedex 15, France; Sorbonne Paris Cité, Paris Descartes University, Rue de l'école de médecine, Paris 75006, France
| | - Nicholas Heming
- General Intensive Care, Assistance Publique Hopitaux de Paris, Raymond Poincaré Teaching Hosptal, Garches 92380, France
| | - Fabrice Chrétien
- Institut Pasteur - Unité Histopathologie Humaine et Modèles Animaux, Département Infection et Épidémiologie, Rue du docteur roux, Paris 75724 Cedex 15, France; Sorbonne Paris Cité, Paris Descartes University, Rue de l'école de médecine, Paris 75006, France; Laboratoire de Neuropathologie, Centre Hospitalier Sainte Anne, 1 rue cabanis, Paris 75014, France
| | - Tarek Sharshar
- Institut Pasteur - Unité Histopathologie Humaine et Modèles Animaux, Département Infection et Épidémiologie, Rue du docteur roux, Paris 75724 Cedex 15, France; General Intensive Care, Assistance Publique Hopitaux de Paris, Raymond Poincaré Teaching Hosptal, Garches 92380, France; Versailles-Saint Quentin University, Avenue de Paris, Versailles 78000, France.
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Catalão CHR, Santos-Júnior NN, da Costa LHA, Souza AO, Alberici LC, Rocha MJA. Brain Oxidative Stress During Experimental Sepsis Is Attenuated by Simvastatin Administration. Mol Neurobiol 2016; 54:7008-7018. [PMID: 27796742 DOI: 10.1007/s12035-016-0218-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 10/12/2016] [Indexed: 12/16/2022]
Abstract
During sepsis, brain damage is associated with oxidative stress due to overproduction of reactive oxygen species (ROS). Although there are recent reports about the benefits of statins in experimental sepsis and endotoxemia in peripheral organs, little is known about their effects in the CNS. Here, we investigated the antioxidant properties of simvastatin and its possible neuroprotective role during experimental sepsis. Male Wistar rats (250-300 g) were submitted to cecal ligation and puncture (CLP, n = 34) or remained as non-manipulated (naive, n = 34). Both groups were treated by gavage with simvastatin (20 mg/kg) or an equivalent volume of saline. The animals submitted to CLP were treated 4 days before and 48 h after surgery. One animal group was decapitated and the blood and brain were collected to quantify plasma levels of cytokines and assess astrogliosis and apoptosis in the prefrontal cortex and hippocampus. Another group was perfused with PBS (0.01 M), and the same brain structures were dissected to analyze oxidative damage. The CLP rats treated with simvastatin showed a reduction in nitric oxide (P < 0.05), IL1-β (P < 0.001), IL-6 (P < 0.01), and TBARS levels (P < 0.001) and an increase in catalase activity (P < 0.01), citrate synthase enzyme (P < 0.05), and normalized GSH/GSSG ratio. In addition, the histopathological analysis showed a reduction (P < 0.001) in reactive astrocytes and caspase 3-positive apoptotic cells. The results suggest a possible neuroprotective effect of simvastatin in structures responsible for spatial learning and memory and indicate the need for behavioral studies evaluating the impact on cognitive damage, as frequently seen in patients surviving sepsis.
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Affiliation(s)
- Carlos Henrique Rocha Catalão
- Department of Neurosciences and Behavioral Sciences of Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Nilton Nascimento Santos-Júnior
- Department of Neurosciences and Behavioral Sciences of Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Luís Henrique Angenendt da Costa
- Department of Neurosciences and Behavioral Sciences of Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Anderson Oliveira Souza
- Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Luciane Carla Alberici
- Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Maria José Alves Rocha
- Department of Morphology, Physiology and Basic Pathology, School of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
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8
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Michels M, Steckert AV, Quevedo J, Barichello T, Dal-Pizzol F. Mechanisms of long-term cognitive dysfunction of sepsis: from blood-borne leukocytes to glial cells. Intensive Care Med Exp 2015; 3:30. [PMID: 26515197 PMCID: PMC4626467 DOI: 10.1186/s40635-015-0066-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 10/21/2015] [Indexed: 12/12/2022] Open
Abstract
Several mechanisms are associated with brain dysfunction during sepsis; one of the most important are activation of microglia and astrocytes. Activation of glial cells induces changes in permeability of the blood-brain barrier, secretion of inflammatory cytokines, and these alterations could induce neuronal dysfunction. Furthermore, blood-borne leukocytes can also reach the brain and participate in inflammatory response. Mechanisms involved in sepsis-associated brain dysfunction were revised here, focusing in neuroinflammation and involvement of blood-borne leukocytes and glial cells in this process.
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Affiliation(s)
- Monique Michels
- Laboratory of Experimental Pathophysiology, Graduate Program in Health Sciences, Health Sciences Unit, University of Southern Santa Catarina, Criciúma, SC, 88806-000, Brazil.
| | - Amanda V Steckert
- Laboratory of Neurosciences, Graduate Program in Health Sciences, Health Sciences Unit, University of Southern Santa Catarina, Criciúma, SC, Brazil.
| | - João Quevedo
- Laboratory of Neurosciences, Graduate Program in Health Sciences, Health Sciences Unit, University of Southern Santa Catarina, Criciúma, SC, Brazil.
- Center for Translational Psychiatry, Department of Psychiatry and Behavioral Sciences, Medical School, The University of Texas at Houston, Houston, TX, USA.
| | - Tatiana Barichello
- Laboratory of Neurosciences, Graduate Program in Health Sciences, Health Sciences Unit, University of Southern Santa Catarina, Criciúma, SC, Brazil.
- Center for Translational Psychiatry, Department of Psychiatry and Behavioral Sciences, Medical School, The University of Texas at Houston, Houston, TX, USA.
| | - Felipe Dal-Pizzol
- Laboratory of Experimental Pathophysiology, Graduate Program in Health Sciences, Health Sciences Unit, University of Southern Santa Catarina, Criciúma, SC, 88806-000, Brazil.
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Huang YN, Ho YJ, Lai CC, Chiu CT, Wang JY. 1,25-Dihydroxyvitamin D3 attenuates endotoxin-induced production of inflammatory mediators by inhibiting MAPK activation in primary cortical neuron-glia cultures. J Neuroinflammation 2015; 12:147. [PMID: 26259787 PMCID: PMC4532256 DOI: 10.1186/s12974-015-0370-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 07/29/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Neuroinflammation occurs in insulted regions of the brain and may be due to reactive oxygen species (ROS), nitric oxide (NO), cytokines, and chemokines produced by activated glia. Excessive production of neurotoxic molecules causes further neuronal damage. Low levels of vitamin D3 are a risk factor for various brain diseases. METHODS Using the bacterial endotoxin, lipopolysaccharide (LPS), to induce neuroinflammation in primary cortical neuron-glia cultures, we investigated how 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) affected neuroinflammation. RESULTS LPS (100 ng/ml) induced the accumulation of nitrite and the production of ROS, interleukin (IL)-6, and macrophage inflammatory protein (MIP)-2 in time-dependent manners. Inhibition of p38 and extracellular signal-regulated kinase (ERK) but not c-Jun N-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) by 20 μM of SB203580, PD98059, and SP600125, significantly reduced LPS-induced ROS production, NO accumulation, and inducible NO synthase (iNOS) expression, respectively. LPS-induced IL-6 and MIP-2 were significantly attenuated by inhibition of p38, ERK, and JNK MAPK. Cotreatment with 1,25(OH)2D3 attenuated LPS-induced ROS production, NO accumulation, and iNOS expression in concentration-dependent manners. 1,25(OH)2D3 also reduced LPS-induced production of IL-6 and MIP-2. Similarly, iNOS, IL-6, and MIP-2 mRNA expression in cells treated with LPS significantly increased, whereas this effect was attenuated by 1,25(OH)2D3. Moreover, LPS-induced phosphorylation of p38, ERK, and JNK MAPK was significantly inhibited by 1,25(OH)2D3. CONCLUSIONS Our findings indicate that 1,25(OH)2D3 reduced the LPS-stimulated production of inflammatory molecules in neuron-glia cultures by inhibiting MAPK pathways and the production of downstream inflammatory molecules. We suggest that 1,25(OH)2D3 can be used to alleviate neuroinflammation in various brain injuries.
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Affiliation(s)
- Ya-Ni Huang
- Department of Nursing, Hsin Sheng Junior College of Medical Care and Management, Taoyuan City, Taiwan.
| | - Yi-Jung Ho
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan. .,Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan.
| | - Chien-Cheng Lai
- Division of Orthopedics, Department of Surgery, Far Eastern Memorial Hospital, New Taipei City, Taiwan.
| | - Chien-Tsai Chiu
- Department of Neurosurgery, En Chu Kong Hospital, New Taipei City, Taiwan.
| | - Jia-Yi Wang
- Graduate Institute of Medical Sciences and Department of Physiology, College of Medicine, Taipei Medical University, 250 Wu-Hsing Street, Taipei, 110, Taiwan.
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10
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Huang YN, Lai CC, Chiu CT, Lin JJ, Wang JY. L-ascorbate attenuates the endotoxin-induced production of inflammatory mediators by inhibiting MAPK activation and NF-κB translocation in cortical neurons/glia Cocultures. PLoS One 2014; 9:e97276. [PMID: 24983461 PMCID: PMC4077707 DOI: 10.1371/journal.pone.0097276] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 04/17/2014] [Indexed: 01/25/2023] Open
Abstract
In response to acute insults to the central nervous system, such as pathogen invasion or neuronal injuries, glial cells become activated and secrete inflammatory mediators such as nitric oxide (NO), cytokines, and chemokines. This neuroinflammation plays a crucial role in the pathophysiology of chronic neurodegenerative diseases. Endogenous ascorbate levels are significantly decreased among patients with septic encephalopathy. Using the bacterial endotoxin lipopolysaccharide (LPS) to induce neuroinflammation in primary neuron/glia cocultures, we investigated how L-ascorbate (vitamin C; Vit. C) affected neuroinflammation. LPS (100 ng/ml) induced the expression of inducible NO synthase (iNOS) and the production of NO, interleukin (IL)-6, and macrophage inflammatory protein-2 (MIP-2/CXCL2) in a time-dependent manner; however, cotreatment with Vit. C (5 or 10 mM) attenuated the LPS-induced iNOS expression and production of NO, IL-6, and MIP-2 production. The morphological features revealed after immunocytochemical staining confirmed that Vit. C suppressed LPS-induced astrocytic and microglial activation. Because Vit. C can be transported into neurons and glia via the sodium-dependent Vit. C transporter-2, we examined how Vit. C affected LPS-activated intracellular signaling in neuron/glia cocultures. The results indicated the increased activation (caused by phosphorylation) of mitogen-activated protein kinases (MAPKs), such as p38 at 30 min and extracellular signal-regulated kinases (ERKs) at 180 min after LPS treatment. The inhibition of p38 and ERK MAPK suppressed the LPS-induced production of inflammatory mediators. Vit. C also inhibited the LPS-induced activation of p38 and ERK. Combined treatments of Vit. C and the inhibitors of p38 and ERK yielded no additional inhibition compared with using the inhibitors alone, suggesting that Vit. C functions through the same signaling pathway (i.e., MAPK) as these inhibitors. Vit. C also reduced LPS-induced IκB-α degradation and NF-κB translocation. Thus, Vit. C suppressed the LPS-stimulated production of inflammatory mediators in neuron/glia cocultures by inhibiting the MAPK and NF-κB signaling pathways.
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Affiliation(s)
- Ya-Ni Huang
- Department of Nursing, Hsin Sheng Junior College of Medical Care and Management, Taoyuan, Taiwan
| | - Chien-Cheng Lai
- Division of Orthopedics, Department of Surgery, Far Eastern Memorial Hospital, New Taipei City, Taiwan
| | - Chien-Tsai Chiu
- Department of Neurosurgery, En Chu Kong Hospital, New Taipei City, Taiwan
| | - Jhen-Jhe Lin
- Graduate Institute of Medical Sciences and Department of Physiology, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Jia-Yi Wang
- Graduate Institute of Medical Sciences and Department of Physiology, College of Medicine, Taipei Medical University, Taipei, Taiwan
- * E-mail:
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11
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Cisternas P, Silva-Alvarez C, Martínez F, Fernandez E, Ferrada L, Oyarce K, Salazar K, Bolaños JP, Nualart F. The oxidized form of vitamin C, dehydroascorbic acid, regulates neuronal energy metabolism. J Neurochem 2014; 129:663-71. [PMID: 24460956 DOI: 10.1111/jnc.12663] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 01/06/2014] [Accepted: 01/09/2014] [Indexed: 11/30/2022]
Abstract
Vitamin C is an essential factor for neuronal function and survival, existing in two redox states, ascorbic acid (AA), and its oxidized form, dehydroascorbic acid (DHA). Here, we show uptake of both AA and DHA by primary cultures of rat brain cortical neurons. Moreover, we show that most intracellular AA was rapidly oxidized to DHA. Intracellular DHA induced a rapid and dramatic decrease in reduced glutathione that was immediately followed by a spontaneous recovery. This transient decrease in glutathione oxidation was preceded by an increase in the rate of glucose oxidation through the pentose phosphate pathway (PPP), and a concomitant decrease in glucose oxidation through glycolysis. DHA stimulated the activity of glucose-6-phosphate dehydrogenase, the rate-limiting enzyme of the PPP. Furthermore, we found that DHA stimulated the rate of lactate uptake by neurons in a time- and dose-dependent manner. Thus, DHA is a novel modulator of neuronal energy metabolism by facilitating the utilization of glucose through the PPP for antioxidant purposes.
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Affiliation(s)
- Pedro Cisternas
- Laboratorio de Neurobiología, Departamento de Biología Celular, Centro de Microscopía Avanzada CMA BIOBIO, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
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12
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Bioenergetics, mitochondrial dysfunction, and oxidative stress in the pathophysiology of septic encephalopathy. Shock 2013; 39 Suppl 1:10-6. [PMID: 23481496 DOI: 10.1097/shk.0b013e31828fade1] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Sepsis is a major cause of mortality and morbidity in intensive care units. Acute and long-term brain dysfunctions have been demonstrated both in experimental models and septic patients. Sepsis-associated encephalopathy is an early and frequent manifestation but is underdiagnosed, because of the absence of specific biomarkers and of confounding factors such as sedatives used in the intensive care unit. Sepsis-associated encephalopathy may have acute and long-term consequences including development of autonomic dysfunction, delirium, and cognitive impairment. The mechanisms of sepsis-associated encephalopathy involve mitochondrial and vascular dysfunctions, oxidative stress, neurotransmission disturbances, inflammation, and cell death. Here we review specific evidence that links bioenergetics, mitochondrial dysfunction, and oxidative stress in the setting of brain dysfunctions associated to sepsis.
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Chen JY, Chang CY, Lan KM, Sheu MJ, Lu CL, Hu ML. Is peptic ulcer disease a risk factor of postherpetic neuralgia in patients with herpes zoster? Med Hypotheses 2013; 81:834-8. [PMID: 24074834 DOI: 10.1016/j.mehy.2013.09.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 08/29/2013] [Accepted: 09/09/2013] [Indexed: 01/21/2023]
Abstract
Postherpetic neuralgia is the most common complication of herpes zoster which is caused by a reactivation of latent varicella zoster virus. The pathogenesis of postherpetic neuralgia may involve peripheral and central mechanisms. Reported risk factors for postherpetic neuralgia include female gender, old age, diminished cell-mediated immunity and nutritional deficiencies. Based on our clinical observation which revealed that peptic ulcer disease (PUD) is one of the common comorbidities in patients with postherpetic neuralgia, we hypothesize that herpes zoster patients with PUD may be at a greater risk for the development of postherpetic neuralgia due to their impaired cellular immunity and depressed nutritional status. Major causes of PUD include Helicobacter pylori infection and usage of ulcerogenic medications. Patients with H. pylori infection may develop T cell dysfunctions and nutritional deficiencies including vitamin C, iron, cobalamin, carotenes and alpha-tocopherol. Ulcerogenic medications such as nonsteroidal anti-inflammatory drugs and steroids have been found not only to be ulcerogenic but also immunosuppressive to T cells. In addition, usage of steroids and nonsteroidal anti-inflammatory drugs may cause deficiencies of alpha-tocopherol, carotenes, cobalamin, iron, zinc and vitamin C. Vitamin C, carotenes and alpha-tocopherol are anti-inflammatory and the major oxidant scavengers in the aqua phase and biomembranes. Deficiencies of these nutrients may induce dysregulated inflammation and oxidative damage leading to neuropathic pain in patients with herpes zoster. Furthermore, nutrient deficiencies including zinc, iron, cobalamin and vitamin C are associated with dysregulation of Ca(v)3.2 T-channels and N-methyl-D-aspartate receptors, upregulation of nitric oxide synthase, the increase of nitric oxide formation and dysfunction of central norepinephrine inhibitory pain pathway. Prospective cohort studies are suggested to test the hypothesis. We further propose that a follow-up study that contains two groups of herpes zoster patients, i.e., with or without gastroendoscopy-proven PUD, be conducted to determine their incidence of postherpetic neuralgia. In addition, despite of the high proportion of zoster patients having been treated with antiviral therapies, prevention and treatment of postherpetic neuralgia remain challenging in clinical practice. The potential risk of postherpetic neuralgia in zoster patients with PUD could mean that physicians need to pay more attention to the comorbidity--PUD in patients with herpes zoster and treat PUD earlier in order to prevent the development of postherpetic neuralgia.
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Affiliation(s)
- Jen-Yin Chen
- Department of Anesthesiology, Chi Mei Medical Center, Tainan, Taiwan; Department of Food Science and Applied Biotechnology, National Chung Hsing University, Taichung, Taiwan; Department of the Senior Citizen Service Management, Chia Nan University of Pharmacy and Science, Tainan, Taiwan
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Adam N, Kandelman S, Mantz J, Chrétien F, Sharshar T. Sepsis-induced brain dysfunction. Expert Rev Anti Infect Ther 2013; 11:211-21. [PMID: 23409826 DOI: 10.1586/eri.12.159] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Systemic infection is often revealed by or associated with brain dysfunction, which is characterized by alteration of consciousness, ranging from delirium to coma, seizure or focal neurological signs. Its pathophysiology involves an ischemic process, secondary to impairment of cerebral perfusion and its determinants and a neuroinflammatory process that includes endothelial activation, alteration of the blood-brain barrier and passage of neurotoxic mediators. Microcirculatory dysfunction is common to these two processes. This brain dysfunction is associated with increased mortality, morbidity and long-term cognitive disability. Its diagnosis relies essentially on neurological examination that can lead to specific investigations, including electrophysiological testing or neuroimaging. In practice, cerebrospinal fluid analysis is indisputably required when meningitis is suspected. Hepatic, uremic or respiratory encephalopathy, metabolic disturbances, drug overdose, sedative or opioid withdrawal, alcohol withdrawal delirium or Wernicke's encephalopathy are the main differential diagnoses. Currently, treatment consists mainly of controlling sepsis. The effects of insulin therapy and steroids need to be assessed. Various drugs acting on sepsis-induced blood-brain barrier dysfunction, brain oxidative stress and inflammation have been tested in septic animals but not yet in patients.
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Affiliation(s)
- Nicolas Adam
- General Intensive Care Unit, Raymond Poincaré Teaching Hospital, University of Versailles Saint-Quentin en Yvelines, 104 Boulevard Raymond Poincaré, 92380 Garches, France
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Abstract
Bacterial bloodstream infection causes septic syndromes that range from systemic inflammatory response syndrome (SIRS) and encephalopathy to severe sepsis and septic shock. Microvascular dysfunction, comprising impaired capillary blood flow and arteriolar responsiveness, precedes multiple organ failure. Vitamin C (ascorbate) levels are low in critically ill patients. The impact of ascorbate administered orally is moderate because of its limited bioavailability. However, intravenous injection of ascorbate raises plasma and tissue concentrations of the vitamin and may decrease morbidity. In animal models of polymicrobial sepsis, intravenous ascorbate injection restores microvascular function and increases survival. The protection of capillary blood flow and arteriolar responsiveness by ascorbate may be mediated by inhibition of oxidative stress, modulation of intracellular signaling pathways, and maintenance of homeostatic levels of nitric oxide. Ascorbate scavenges reactive oxygen species (ROS) and also inhibits the NADPH oxidase that synthesizes superoxide in microvascular endothelial cells. The resulting changes in redox-sensitive signaling pathways may diminish endothelial expression of inducible nitric oxide synthase (iNOS), tissue factor and adhesion molecules. Ascorbate also regulates nitric oxide concentration by releasing nitric oxide from adducts and by acting through tetrahydrobiopterin (BH4) to stimulate endothelial nitric oxide synthase (eNOS). Therefore, it may be possible to improve microvascular function in sepsis by using intravenous vitamin C as an adjunct therapy.
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Affiliation(s)
- John X Wilson
- Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY, 14214-8028, USA,
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Des pathologies encéphaliques à connaître — L'encéphalopathie associée au sepsis et ses diagnostics différentiels. MEDECINE INTENSIVE REANIMATION 2011. [DOI: 10.1007/s13546-010-0118-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Checinski A, Polito A, Friedman D, Siami S, Annane D, Sharshar T. Sepsis-associated encephalopathy and its differential diagnosis. FUTURE NEUROLOGY 2010. [DOI: 10.2217/fnl.10.62] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Sepsis-associated encephalopathy (SAE) is defined as a diffuse cerebral dysfunction resulting from the systemic inflammatory response to an infection without direct infestation of the CNS. Although the pathophysiology of SAE is as yet unknown, some mechanisms have been suggested that involve BBB disruption as a consequence of proinflammatory mediators’ effects on endothelial cells. This leads to an increased passage of neurotoxic and proinflammatory mediators into the brain parenchyma, as well as an impairment of the movements of oxygen and metabolites through the BBB. Both neurons and glial cells are affected, resulting in neural functioning and neurotransmission impairment. The clinical translation of this process is an alteration of consciousness and awareness. SAE is a frequent condition in septic patients. Despite being considered reversible, SAE appears to be associated with long-term cognitive impairment. Detection and diagnosis can be challenging; it requires daily neurological assessment with the assistance of clinical scores. Use of biomarkers and neurophysiological testing is discussed. The aim of this article is to provide practical tools for detection of SAE, as well as an updated overview of its pathophysiology and therapeutic perspectives.
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Affiliation(s)
- Anthony Checinski
- General Intensive Care Unit, Raymond Poincaré Teaching Hospital (AP-HP), University of Versailles Saint-Quentin en Yvelines 104, Boulevard Raymond Poincaré, 92380 Garches, France
| | - Andrea Polito
- General Intensive Care Unit, Raymond Poincaré Teaching Hospital (AP-HP), University of Versailles Saint-Quentin en Yvelines 104, Boulevard Raymond Poincaré, 92380 Garches, France
| | - Diane Friedman
- General Intensive Care Unit, Raymond Poincaré Teaching Hospital (AP-HP), University of Versailles Saint-Quentin en Yvelines 104, Boulevard Raymond Poincaré, 92380 Garches, France
| | - Shidasp Siami
- Department of Intensive Care Medicine, Hospital of Sud Essonne, Etampes, France
| | - Djillali Annane
- General Intensive Care Unit, Raymond Poincaré Teaching Hospital (AP-HP), University of Versailles Saint-Quentin en Yvelines 104, Boulevard Raymond Poincaré, 92380 Garches, France
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Abstract
Sepsis is often complicated by an acute and reversible deterioration of mental status, which is associated with increased mortality and is consistent with delirium but can also be revealed by a focal neurologic sign. Sepsis-associated encephalopathy is accompanied by abnormalities of electroencephalogram and somatosensory-evoked potentials, increased in biomarkers of brain injury (i.e., neuron-specific enolase, S-100 beta-protein) and, frequently, by neuroradiological abnormalities, notably leukoencephalopathy. Its mechanism is highly complex, resulting from both inflammatory and noninflammatory processes that affect all brain cells and induce blood-brain barrier breakdown, dysfunction of intracellular metabolism, brain cell death, and brain injuries. Its diagnosis relies essentially on neurologic examination that can lead one to perform specific neurologic tests. Electroencephalography is required in the presence of seizure; neuroimaging in the presence of seizure, focal neurologic signs or suspicion of cerebral infection; and both when encephalopathy remains unexplained. In practice, cerebrospinal fluid analysis should be performed if there is any doubt of meningitis. Hepatic, uremic, or respiratory encephalopathy, metabolic disturbances, drug overdose, withdrawal of sedatives or opioids, alcohol withdrawal delirium, and Wernicke's encephalopathy are the main differential diagnoses of sepsis-associated encephalopathy. Patient management is based mainly on controlling infection, organ system failure, and metabolic homeostasis, at the same time avoiding neurotoxic drugs.
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Siami S, Polito A, Sharshar T. Sepsis-associated Encephalopathy. Intensive Care Med 2009. [DOI: 10.1007/978-0-387-92278-2_74] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Saura J. Microglial cells in astroglial cultures: a cautionary note. J Neuroinflammation 2007; 4:26. [PMID: 17937799 PMCID: PMC2140055 DOI: 10.1186/1742-2094-4-26] [Citation(s) in RCA: 172] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2007] [Accepted: 10/15/2007] [Indexed: 01/25/2023] Open
Abstract
Primary rodent astroglial-enriched cultures are the most popular model to study astroglial biology in vitro. From the original methods described in the 1970's a great number of minor modifications have been incorporated into these protocols by different laboratories. These protocols result in cultures in which the astrocyte is the predominant cell type, but astrocytes are never 100% of cells in these preparations. The aim of this review is to bring attention to the presence of microglia in astroglial cultures because, in my opinion, the proportion of and the role that microglial cells play in astroglial cultures are often underestimated. The main problem with ignoring microglia in these cultures is that relatively minor amounts of microglia can be responsible for effects observed on cultures in which the astrocyte is the most abundant cell type. If the relative contributions of astrocytes and microglia are not properly assessed an observed effect can be erroneously attributed to the astrocytes. In order to illustrate this point the case of NO production in activated astroglial-enriched cultures is examined. Lipopolysaccharide (LPS) induces nitric oxide (NO) production in astroglial-enriched cultures and this effect is very often attributed to astrocytes. However, a careful review of the published data suggests that LPS-induced NO production in rodent astroglial-enriched cultures is likely to be mainly microglial in origin. This review considers cell culture protocol factors that can affect the proportion of microglial cells in astroglial cultures, strategies to minimize the proportion of microglia in these cultures, and specific markers that allow the determination of such microglial proportions.
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Affiliation(s)
- Josep Saura
- Department of Cerebral Ischaemia and Neurodegeneration, Institute for Biomedical Research of Barcelona (IIBB), CSIC, IDIBAPS, 08036-Barcelona, Spain.
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Fransson LA, Mani K. Novel aspects of vitamin C: how important is glypican-1 recycling? Trends Mol Med 2007; 13:143-9. [PMID: 17344097 DOI: 10.1016/j.molmed.2007.02.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2006] [Revised: 02/06/2007] [Accepted: 02/22/2007] [Indexed: 02/04/2023]
Abstract
The reduced form of vitamin C, ascorbic acid, is well known for its function as an antioxidant and as a protective agent against scurvy. However, many recent studies indicate other functions for vitamin C in mammalian cells. Novel findings provide possible explanations for observed beneficial effects of a high intake of vitamin C on cell growth, gene transcription, host resistance to infection, uptake of polyamines and clearance of misfolded proteins. Vitamin C exerts its effects indirectly via hypoxia-inducible factor, nitric oxide synthase and the heparan sulfate proteoglycan glypican-1, which is deglycanated in a vitamin C- and copper-dependent reaction.
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Affiliation(s)
- Lars-Ake Fransson
- Department of Experimental Medical Science, Division of Neuroscience, Glycobiology Group, Biomedical Centre A13, Lund University, Lund, Sweden. lars-ake@
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Barichello T, Fortunato JJ, Vitali AM, Feier G, Reinke A, Moreira JCF, Quevedo J, Dal-Pizzol F. Oxidative variables in the rat brain after sepsis induced by cecal ligation and perforation. Crit Care Med 2006; 34:886-9. [PMID: 16505668 DOI: 10.1097/01.ccm.0000201880.50116.12] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The underlying mechanisms of the changes in mental status, septic encephalopathy, and long-term cognitive symptoms in sepsis survivors have only been defined in part. The present study was undertaken to assess different variables of oxidative stress in several brain structures after cecal ligation and perforation in the rat. DESIGN Prospective animal study. SETTING Animal basic science laboratory. SUBJECTS Male Wistar rats, weighing 250-350 g. INTERVENTIONS Rats were subjected to cecal ligation and perforation (sepsis group) with saline resuscitation (at 50 mL/kg immediately and 12 hrs after cecal ligation and perforation) or sham operation (control group). MEASUREMENTS AND MAIN RESULTS Oxidative damage, assessed by the thiobarbituric acid reactive species and the protein carbonyl assays, occurred early (after 6 hrs) in the course of sepsis development in the hippocampus, cerebellum, and cortex. At longer times after sepsis induction (12-96 hrs), there was no evidence of oxidative damage in all analyzed structures. Except for the striatum, earlier in sepsis development (6 hrs) we demonstrated an increase in superoxide dismutase activity without a proportional increase in catalase activity with a consequent increase in the relation of superoxide dismutase/catalase. The balance between these enzymes was restored in the studied structures 12-96 hrs after sepsis induction. CONCLUSIONS The short-term oxidative damage demonstrated here could participate in the development of central nervous system symptoms during sepsis development, or even septic encephalopathy. The alterations in the superoxide dismutase/catalase relation were temporally related to the occurrence or not of oxidative damage in the central nervous system.
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Affiliation(s)
- Tatiana Barichello
- Laboratório de Neurociências, Universidade do Extremo Sul Catarinense, Criciúma, SC, Brazil
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Dragan M, Dixon SJ, Jaworski E, Chan TS, O'brien PJ, Wilson JX. Coenzyme Q(1) depletes NAD(P)H and impairs recycling of ascorbate in astrocytes. Brain Res 2006; 1078:9-18. [PMID: 16499885 DOI: 10.1016/j.brainres.2006.01.068] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2005] [Revised: 01/17/2006] [Accepted: 01/18/2006] [Indexed: 12/13/2022]
Abstract
Ascorbate is an important antioxidant in the brain. Astrocytes are capable of recycling ascorbate by taking up and then reducing its oxidation product dehydroascorbic acid (DHAA) using reducing equivalents derived from NAD(P)H. Astrocytes also contain NAD(P)H-dependent quinone reductases, such as NAD(P)H:quinone oxidoreductase (NQO1), which are capable of reducing coenzyme Q and its analogs. Short-chain coenzyme Q analogs have been proposed as therapeutic agents for neurodegenerative illnesses, but they may cause oxidative stress by non-enzymatic redox cycling or enzyme-dependent depletion of NAD(P)H. Therefore, we tested the hypothesis that the short-chain coenzyme Q analog coenzyme Q(1) (CoQ(1), ubiquinone-5) decreases intracellular NAD(P)H levels in astrocytes and impairs the ability of these cells to replace extracellular DHAA with ascorbate (i.e., ascorbate recycling). We observed that CoQ(1) inhibited the production of intra- and extracellular ascorbate by primary rat astrocytes incubated with DHAA in glucose-free medium. Reduction of CoQ(1) to CoQ(1)H(2) by astrocytes was partially blocked by the NQO1 inhibitor dicumarol but was not affected by DHAA. The inhibition of ascorbate recycling by CoQ(1) was attenuated by dicumarol and was abolished by glucose. CoQ(1) lowered intracellular levels of reactive oxygen species, as measured by oxidation of 2',7'-dichlorofluorescin but also produced marked decreases in the concentrations of NADH and NADPH. We conclude that in astrocytes CoQ(1) recycling depletes NAD(P)H and inhibits ascorbate recycling when glucose metabolism is limited. Because DHAA can cause cell-lethal oxidative stress in neurons and ascorbate produced by astrocytes may be neuroprotective, coenzyme Q analogs may adversely affect brain function through this novel mechanism.
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Affiliation(s)
- Magdalena Dragan
- Department of Physiology and Pharmacology, Faculty of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada N6A 5C1
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Wilson JX, Dragan M. Sepsis inhibits recycling and glutamate-stimulated export of ascorbate by astrocytes. Free Radic Biol Med 2005; 39:990-8. [PMID: 16198226 DOI: 10.1016/j.freeradbiomed.2005.05.020] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2005] [Revised: 05/04/2005] [Accepted: 05/12/2005] [Indexed: 11/29/2022]
Abstract
Sepsis causes brain dysfunction. Because neurotransmission requires high ascorbate and low dehydroascorbic acid (DHAA) concentrations in brain extracellular fluid, the effect of septic insult on ascorbate recycling (i.e., uptake and reduction of DHAA) and export was investigated in primary rat and mouse astrocytes. DHAA raised intracellular ascorbate to physiological levels but extracellular ascorbate only slightly. Septic insult by lipopolysaccharide and interferon-gamma increased ascorbate recycling in astrocytes permeabilized with saponin but decreased it in those with intact plasma membrane. The decrease was due to inhibition of the glucose transporter (GLUT1) that translocates DHAA because septic insult slowed uptake of the nonmetabolizable GLUT1 substrate 3-O-methylglucose. Septic insult also abolished stimulation by glutamate of ascorbate export. Specific nitric oxide synthase (NOS) inhibitors and nNOS and iNOS deficiency failed to alter the effects of septic insult. Inhibitors of NADPH oxidase generally did not protect against septic insult, because only one of those tested (diphenylene iodonium) increased GLUT1 activity and ascorbate recycling. We conclude that astrocytes take up DHAA and use it to synthesize ascorbate that is exported in response to glutamate. This mechanism may provide the antioxidant on demand to neurons under normal conditions, but it is attenuated after septic insult.
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Affiliation(s)
- John X Wilson
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada N6A 5C1.
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Kuo SM, Tan CH, Dragan M, Wilson JX. Endotoxin increases ascorbate recycling and concentration in mouse liver. J Nutr 2005; 135:2411-6. [PMID: 16177205 PMCID: PMC1343533 DOI: 10.1093/jn/135.10.2411] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Sublethal exposure to Escherichia coli endotoxin [lipopolysaccharide (LPS)] attenuates the lethal effects of subsequent insults associated with oxidative stress, such as higher LPS dose, septic peritonitis, and ischemia. Because administration of the antioxidant ascorbate protects against these same insults and injection of dehydroascorbic acid (DHAA) protects against ischemia, the hypothesis that sublethal LPS increases endogenous ascorbate concentration and recycling (i.e., synthesis from DHAA) was tested. Injection of LPS [5 x 10(6) endotoxin units/kg body weight, i.p.] in mice caused a temporary inhibition of food intake, which was significant by 20 h and recovered within 3 d. LPS increased ascorbate concentration in adrenal gland, heart, kidney, and liver. LPS had similar effects in wild-type and Slc23a2+/- mice despite the latter's deficiency in the ascorbate transporter SVCT2. In liver, the ascorbate response to LPS was not accompanied by change in glutathione concentration. LPS decreased gulonolactone oxidase activity, which is rate-limiting for de novo synthesis of ascorbate from glucose, but increased the rate of DHAA reduction to ascorbate. In conclusion, sublethal endotoxin increases ascorbate recycling in liver and ascorbate concentration in liver, adrenal gland, heart, and kidney. The enhanced rate of ascorbate production from DHAA may protect these organs against the reactive oxygen species produced by subsequent, potentially lethal challenges.
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Affiliation(s)
| | | | | | - John X. Wilson
- Correspondence: Dr. John X. Wilson, Department of Exercise and Nutrition Sciences, University at Buffalo, Kimball Tower, Room 410, Buffalo, NY 14214-8028, USA. Tel: (716) 829-2941 extension 408. Fax: (716) 829-2428. E-mail:
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Abstract
Ascorbic acid and dehydroascorbic acid (DHAA, oxidized vitamin C) are dietary sources of vitamin C in humans. Both nutrients are absorbed from the lumen of the intestine and renal tubules by, respectively, enterocytes and renal epithelial cells. Subsequently vitamin C circulates in the blood and enters all of the other cells of the body. Concerning flux across the plasma membrane, simple diffusion of ascorbic acid plays only a small or negligible role. More important are specific mechanisms of transport and metabolism that concentrate vitamin C intracellularly to enhance its function as an enzyme cofactor and antioxidant. The known transport mechanisms are facilitated diffusion of DHAA through glucose-sensitive and -insensitive transporters, facilitated diffusion of ascorbate through channels, exocytosis of ascorbate in secretory vesicles, and secondary active transport of ascorbate through the sodium-dependent vitamin C transporters SVCT1 and SVCT2 proteins that are encoded by the genes Slc23a1 and Slc23a2, respectively. Evidence is reviewed indicating that these transport pathways are regulated under physiological conditions and altered by aging and disease.
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Affiliation(s)
- John X Wilson
- Department of Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, Buffalo, New York 14214-3079, USA.
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Yao HH, Ding JH, Zhou F, Wang F, Hu LF, Sun T, Hu G. Enhancement of glutamate uptake mediates the neuroprotection exerted by activating group II or III metabotropic glutamate receptors on astrocytes. J Neurochem 2005; 92:948-61. [PMID: 15686497 DOI: 10.1111/j.1471-4159.2004.02937.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We investigated whether the activation of astroglial group II and III metabotropic glutamate receptors (mGluRs) could exert neuroprotective effects and whether the neuroprotection was related to glutamate uptake. Our results showed that the activation of astroglial group II or III mGluRs exerted neuroprotection against 1-methyl-4-phenylpyridinium (MPP+) astroglial conditioned medium-induced neurotoxicity in midbrain neuron cultures. Furthermore, MPP+ decreased glutamate uptake of primary astrocytes and C6 glioma cells, which was recovered by activating group II or III mGluRs. Specific group II or III mGluRs antagonists completely abolished the neuroprotective effects and the enhancement of glutamate uptake of their respective agonists. Our results showed that the primary cultured rat astrocytes and C6 glioma cells expressed receptor proteins for group II mGluR2/3, group III mGluR4, mGluR6 and mGluR7. C6 glioma cells expressed mRNA for group II mGluR3, group III mGluR4, mGluR6, mGluR7 and mGluR8. In conclusion, we confirmed that the activation of astroglial mGluRs exerted neuroprotection, and demonstrated that the mechanism underlying this protective role was at least partially related to the enhancement of glutamate uptake.
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Affiliation(s)
- Hong-Hong Yao
- Department of Pharmacology & Neurobiology, Nanjing Medical University, Nanjing City, Jiangsu Province, China
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Fernandes A, Silva RFM, Falcão AS, Brito MA, Brites D. Cytokine production, glutamate release and cell death in rat cultured astrocytes treated with unconjugated bilirubin and LPS. J Neuroimmunol 2004; 153:64-75. [PMID: 15265664 DOI: 10.1016/j.jneuroim.2004.04.007] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2004] [Revised: 04/21/2004] [Accepted: 04/21/2004] [Indexed: 11/19/2022]
Abstract
In hyperbilirubinemic newborns, sepsis is considered a risk factor for kernicterus. Evidence shows that injury to astrocytes triggers cytokine release. We examined the effects of unconjugated bilirubin (UCB) alone, or in combination with LPS, on the release of glutamate and cytokines from astrocytes in conditions inducing less than 10% of cell death. UCB leads to an increase of extracellular glutamate and highly enhances the release of TNF-alpha and IL-1beta, while inhibiting the production of IL-6. LPS potentiates immunostimulatory properties of UCB. These results point out the role of cytokines and provide a basis for the significance of sepsis in UCB encephalopathy.
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Affiliation(s)
- Adelaide Fernandes
- Centro de Patogénese Molecular (UBMBE), Faculdade de Farmácia, University of Lisbon, Av. Forças Armadas, 1600-083 Lisbon, Portugal
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Walsh KA, Megyesi JF, Wilson JX, Crukley J, Laubach VE, Hammond RR. Antioxidant protection from HIV-1 gp120-induced neuroglial toxicity. J Neuroinflammation 2004; 1:8. [PMID: 15285794 PMCID: PMC483061 DOI: 10.1186/1742-2094-1-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2004] [Accepted: 05/27/2004] [Indexed: 11/17/2022] Open
Abstract
Background The pathogenesis of HIV-1 glycoprotein 120 (gp120) associated neuroglial toxicity remains unresolved, but oxidative injury has been widely implicated as a contributing factor. In previous studies, exposure of primary human central nervous system tissue cultures to gp120 led to a simplification of neuronal dendritic elements as well as astrocytic hypertrophy and hyperplasia; neuropathological features of HIV-1-associated dementia. Gp120 and proinflammatory cytokines upregulate inducible nitric oxide synthase (iNOS), an important source of nitric oxide (NO) and nitrosative stress. Because ascorbate scavenges reactive nitrogen and oxygen species, we studied the effect of ascorbate supplementation on iNOS expression as well as the neuronal and glial structural changes associated with gp120 exposure. Methods Human CNS cultures were derived from 16–18 week gestation post-mortem fetal brain. Cultures were incubated with 400 μM ascorbate-2-O-phosphate (Asc-p) or vehicle for 18 hours then exposed to 1 nM gp120 for 24 hours. The expression of iNOS and neuronal (MAP2) and astrocytic (GFAP) structural proteins was examined by immunohistochemistry and immunofluorescence using confocal scanning laser microscopy (CSLM). Results Following gp120 exposure iNOS was markedly upregulated from undetectable levels at baseline. Double label CSLM studies revealed astrocytes to be the prime source of iNOS with rare neurons expressing iNOS. This upregulation was attenuated by the preincubation with Asc-p, which raised the intracellular concentration of ascorbate. Astrocytic hypertrophy and neuronal injury caused by gp120 were also prevented by preincubation with ascorbate. Conclusions Ascorbate supplementation prevents the deleterious upregulation of iNOS and associated neuronal and astrocytic protein expression and structural changes caused by gp120 in human brain cell cultures.
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Affiliation(s)
- Kimberley A Walsh
- Department of Pathology, London Health Sciences Centre, University of Western Ontario, London, ON, Canada
| | - Joseph F Megyesi
- Department of Pathology, London Health Sciences Centre, University of Western Ontario, London, ON, Canada
- Department Clinical Neurological Sciences, London Health Sciences Centre, University of Western Ontario, London, ON, Canada
| | - John X Wilson
- Department Physiology, University of Western Ontario, London, ON, Canada
| | - Jeff Crukley
- Department of Pathology, London Health Sciences Centre, University of Western Ontario, London, ON, Canada
| | - Victor E Laubach
- Department of Surgery, University of Virginia Health System, Charlottesville, VA, USA
| | - Robert R Hammond
- Department of Pathology, London Health Sciences Centre, University of Western Ontario, London, ON, Canada
- Department Clinical Neurological Sciences, London Health Sciences Centre, University of Western Ontario, London, ON, Canada
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Wu F, Wilson JX, Tyml K. Ascorbate inhibits iNOS expression and preserves vasoconstrictor responsiveness in skeletal muscle of septic mice. Am J Physiol Regul Integr Comp Physiol 2003; 285:R50-6. [PMID: 12637347 DOI: 10.1152/ajpregu.00564.2002] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Inducible nitric oxide synthase (iNOS) expression in blood vessels contributes to the vascular hyporeactivity characteristic of sepsis. Our previous work demonstrated in vitro that ascorbate inhibits iNOS expression in lipopolysaccharide- and interferon-gamma-stimulated skeletal muscle endothelial cells (ECs) through an antioxidant mechanism. The present study evaluated in vivo the hypothesis that administration of ascorbate decreases oxidative stress, prevents endothelial iNOS expression, and improves vascular reactivity in septic skeletal muscle. Sepsis was induced in C57BL/6 mice by cecal ligation and puncture (CLP). Plasma nitrite and nitrate (NOx) levels were elevated by 6 h after CLP. Prior ascorbate bolus injection (200 mg/kg body wt iv) blocked the elevation of plasma NOx and abolished the expression of iNOS protein and activity in the septic skeletal muscle. We also demonstrated that iNOS mRNA determined by RT-PCR was induced in the microvascular ECs of the muscle at 3 h after CLP. This induction was attenuated by prior ascorbate administration. Ascorbate inhibition of iNOS expression was associated with decreased oxidant levels in the septic muscle. Moreover, ascorbate administration restored partially the baseline arterial pressure and preserved completely the microvascular constriction and arterial pressure responses to norepinephrine in CLP mice. These results suggest that early administration of ascorbate may be a valuable adjunct treatment of sepsis.
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Affiliation(s)
- Feng Wu
- Dept. of Medical Biophysics, University of Western Ontario, London, ON, Canada N6C 5C1
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Wilson JX, Young GB. Progress in clinical neurosciences: sepsis-associated encephalopathy: evolving concepts. Can J Neurol Sci 2003; 30:98-105. [PMID: 12774948 DOI: 10.1017/s031716710005335x] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Systemic sepsis commonly produces brain dysfunction, sepsis-associated encephalopathy, which can vary from a transient, reversible encephalopathy to irreversible brain damage. The encephalopathy in the acute phase clinically resembles many metabolic encephalopathies: a diffuse disturbance in cerebral function with sparing of the brain stem. The severity of the encephalopathy, as reflected in progressive EEG abnormalities, often precedes then parallels dysfunction in other organs. Recent research has revealed a number of potentially important, non-mutually exclusive, mechanisms that have therapeutic implications.
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Affiliation(s)
- John X Wilson
- Department of Physiology, University of Western Ontario, London, Ontario, Canada
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Abstract
Dehydroascorbic acid (DHA) is abundant in the human diet and also is generated from vitamin C (ascorbic acid, AA) in the lumen of the gastrointestinal tract. DHA is absorbed from the lumen of the small intestine and reduced to AA, which subsequently circulates in the blood. Utilization of AA as an antioxidant and enzyme cofactor causes its oxidation to DHA in extracellular fluid and cells. DHA has an important role in many cell types because it can be used to regenerate AA. Both physiological (e.g. insulin, insulin-like growth factor I, cyclic AMP) and pathological (e.g. oxidative stress, diabetes, sepsis) factors alter the transport and metabolic mechanisms responsible for this DHA recycling.
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Affiliation(s)
- John X Wilson
- Department of Physiology, Faculty of Medicine and Dentistry, University of Western Ontario, London, ON, Canada N6A 5C1.
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