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Mohamed B, Yarlagadda K, Self Z, Simon A, Rigueiro F, Sohooli M, Eisenschenk S, Doré S. Obstructive Sleep Apnea and Stroke: Determining the Mechanisms Behind their Association and Treatment Options. Transl Stroke Res 2024; 15:239-332. [PMID: 36922470 DOI: 10.1007/s12975-023-01123-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 01/02/2023] [Accepted: 01/02/2023] [Indexed: 03/18/2023]
Abstract
Sleep-disordered breathing (SDB) can be a sequela of stroke caused by vascular injury to vital respiratory centers, cerebral edema, and increased intracranial pressure of space-occupying lesions. Likewise, obstructive sleep apnea (OSA) contributes to increased stroke risk through local mechanisms such as impaired ischemic cerebrovascular response and systemic effects such as promoting atherosclerosis, hypercoagulability, cardiac arrhythmias, vascular-endothelial dysfunction, and metabolic syndrome. The impact of OSA on stroke outcomes has been established, yet it receives less attention in national guidelines on stroke management than hyperglycemia and blood pressure dysregulation. Furthermore, whether untreated OSA worsens stroke outcomes is not well-described in the literature. This scoping review provides an updated investigation of the correlation between OSA and stroke, including inter-relational pathophysiology. This review also highlights the importance of OSA treatment and its role in stroke outcomes. Knowledge of pathophysiology, the inter-relationship between these common disorders, and the impact of OSA therapy on outcomes affect the clinical management of patients with acute ischemic stroke. In addition, understanding the relationship between stroke outcomes and pre-existing OSA will allow clinicians to predict outcomes while treating acute stroke.
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Affiliation(s)
- Basma Mohamed
- Department of Anesthesiology, Center for Translational Research in Neurodegenerative Disease, University of Florida College of Medicine, Gainesville, FL, 32610, USA
| | - Keerthi Yarlagadda
- Department of Anesthesiology, Center for Translational Research in Neurodegenerative Disease, University of Florida College of Medicine, Gainesville, FL, 32610, USA
| | - Zachary Self
- Department of Anesthesiology, Center for Translational Research in Neurodegenerative Disease, University of Florida College of Medicine, Gainesville, FL, 32610, USA
| | - Alexandra Simon
- Department of Anesthesiology, Center for Translational Research in Neurodegenerative Disease, University of Florida College of Medicine, Gainesville, FL, 32610, USA
| | - Frank Rigueiro
- Department of Anesthesiology, Center for Translational Research in Neurodegenerative Disease, University of Florida College of Medicine, Gainesville, FL, 32610, USA
| | - Maryam Sohooli
- Department of Anesthesiology, Center for Translational Research in Neurodegenerative Disease, University of Florida College of Medicine, Gainesville, FL, 32610, USA
| | - Stephan Eisenschenk
- Department of Neurology, University of Florida College of Medicine, Gainesville, FL, 32610, USA
| | - Sylvain Doré
- Department of Anesthesiology, Center for Translational Research in Neurodegenerative Disease, University of Florida College of Medicine, Gainesville, FL, 32610, USA.
- Department of Neurology, University of Florida College of Medicine, Gainesville, FL, 32610, USA.
- Departments of Neurology, Psychiatry, Pharmaceutics, and Neuroscience, Center for Translational Research in Neurodegenerative Disease, McKnight Brain Institute, University of Florida College of Medicine, Gainesville, FL, 32610, USA.
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Colucci ACM, Tassinari ID, Loss EDS, de Fraga LS. History and Function of the Lactate Receptor GPR81/HCAR1 in the Brain: A Putative Therapeutic Target for the Treatment of Cerebral Ischemia. Neuroscience 2023; 526:144-163. [PMID: 37391123 DOI: 10.1016/j.neuroscience.2023.06.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 06/21/2023] [Accepted: 06/24/2023] [Indexed: 07/02/2023]
Abstract
GPR81 is a G-protein coupled receptor (GPCR) discovered in 2001, but deorphanized only 7 years later, when its affinity for lactate as an endogenous ligand was demonstrated. More recently, GPR81 expression and distribution in the brain were also confirmed and the function of lactate as a volume transmitter has been suggested since then. These findings shed light on a new function of lactate acting as a signaling molecule in the central nervous system, in addition to its well-known role as a metabolic fuel for neurons. GPR81 seems to act as a metabolic sensor, coupling energy metabolism, synaptic activity, and blood flow. Activation of this receptor leads to Gi-mediated downregulation of adenylyl cyclase and subsequent reduction in cAMP levels, regulating several downstream pathways. Recent studies have also suggested the potential role of lactate as a neuroprotective agent, mainly under brain ischemic conditions. This effect is usually attributed to the metabolic role of lactate, but the underlying mechanisms need further investigation and could be related to lactate signaling via GPR81. The activation of GPR81 showed promising results for neuroprotection: it modulates many processes involved in the pathophysiology of ischemia. In this review, we summarize the history of GPR81, starting with its deorphanization; then, we discuss GPR81 expression and distribution, signaling transduction cascades, and neuroprotective roles. Lastly, we propose GPR81 as a potential target for the treatment of cerebral ischemia.
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Affiliation(s)
- Anna Clara Machado Colucci
- Laboratório de Neurobiologia e Metabolismo (NeuroMet), Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul (UFRGS), Rua Ramiro Barcelos, 2600, lab. 660, Porto Alegre, Brazil; Programa de Pós-Graduação em Ciências Biológicas: Fisiologia, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul (UFRGS), Rua Ramiro Barcelos, 2600, Porto Alegre, Brazil; Centro de Pesquisa Experimental, Hospital de Clínicas de Porto Alegre (HCPA), Rua Ramiro Barcelos, 2350, Porto Alegre, Brazil
| | - Isadora D'Ávila Tassinari
- Laboratório de Neurobiologia e Metabolismo (NeuroMet), Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul (UFRGS), Rua Ramiro Barcelos, 2600, lab. 660, Porto Alegre, Brazil; Programa de Pós-Graduação em Ciências Biológicas: Fisiologia, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul (UFRGS), Rua Ramiro Barcelos, 2600, Porto Alegre, Brazil; Centro de Pesquisa Experimental, Hospital de Clínicas de Porto Alegre (HCPA), Rua Ramiro Barcelos, 2350, Porto Alegre, Brazil
| | - Eloísa da Silveira Loss
- Laboratório de Endocrinologia Experimental (LABENEX), Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul (UFRGS), Rua Ramiro Barcelos, 2600, lab. 660, Porto Alegre, Brazil; Programa de Pós-Graduação em Ciências Biológicas: Fisiologia, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul (UFRGS), Rua Ramiro Barcelos, 2600, Porto Alegre, Brazil
| | - Luciano Stürmer de Fraga
- Laboratório de Neurobiologia e Metabolismo (NeuroMet), Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul (UFRGS), Rua Ramiro Barcelos, 2600, lab. 660, Porto Alegre, Brazil; Programa de Pós-Graduação em Ciências Biológicas: Fisiologia, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul (UFRGS), Rua Ramiro Barcelos, 2600, Porto Alegre, Brazil; Centro de Pesquisa Experimental, Hospital de Clínicas de Porto Alegre (HCPA), Rua Ramiro Barcelos, 2350, Porto Alegre, Brazil.
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Qiu X, Li L, Wei J, An X, Ampadu JA, Zheng W, Yu C, Peng C, Li X, Cai X. The protective role of Nrf2 on cognitive impairment in chronic intermittent hypoxia and sleep fragmentation mice. Int Immunopharmacol 2023; 116:109813. [DOI: 10.1016/j.intimp.2023.109813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 01/13/2023] [Accepted: 01/28/2023] [Indexed: 02/16/2023]
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Krakovski MA, Arora N, Jain S, Glover J, Dombrowski K, Hernandez B, Yadav H, Sarma AK. Diet-microbiome-gut-brain nexus in acute and chronic brain injury. Front Neurosci 2022; 16:1002266. [PMID: 36188471 PMCID: PMC9523267 DOI: 10.3389/fnins.2022.1002266] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 08/29/2022] [Indexed: 11/13/2022] Open
Abstract
In recent years, appreciation for the gut microbiome and its relationship to human health has emerged as a facilitator of maintaining healthy physiology and a contributor to numerous human diseases. The contribution of the microbiome in modulating the gut-brain axis has gained significant attention in recent years, extensively studied in chronic brain injuries such as Epilepsy and Alzheimer’s Disease. Furthermore, there is growing evidence that gut microbiome also contributes to acute brain injuries like stroke(s) and traumatic brain injury. Microbiome-gut-brain communications are bidirectional and involve metabolite production and modulation of immune and neuronal functions. The microbiome plays two distinct roles: it beneficially modulates immune system and neuronal functions; however, abnormalities in the host’s microbiome also exacerbates neuronal damage or delays the recovery from acute injuries. After brain injury, several inflammatory changes, such as the necrosis and apoptosis of neuronal tissue, propagates downward inflammatory signals to disrupt the microbiome homeostasis; however, microbiome dysbiosis impacts the upward signaling to the brain and interferes with recovery in neuronal functions and brain health. Diet is a superlative modulator of microbiome and is known to impact the gut-brain axis, including its influence on acute and neuronal injuries. In this review, we discussed the differential microbiome changes in both acute and chronic brain injuries, as well as the therapeutic importance of modulation by diets and probiotics. We emphasize the mechanistic studies based on animal models and their translational or clinical relationship by reviewing human studies.
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Affiliation(s)
| | - Niraj Arora
- Department of Neurology, University of Missouri, Columbia, MO, United States
| | - Shalini Jain
- Department of Neurosurgery and Brain Repair, University of South Florida, Tampa, FL, United States
| | - Jennifer Glover
- Department of Neurosurgery and Brain Repair, University of South Florida, Tampa, FL, United States
| | - Keith Dombrowski
- Department of Neurosurgery and Brain Repair, University of South Florida, Tampa, FL, United States
| | - Beverly Hernandez
- Clinical Nutrition Services, Tampa General Hospital, Tampa, FL, United States
| | - Hariom Yadav
- Department of Neurosurgery and Brain Repair, University of South Florida, Tampa, FL, United States
- USF Center for Microbiome Research, Microbiomes Institute, University of South Florida, Tampa, FL, United States
- *Correspondence: Hariom Yadav,
| | - Anand Karthik Sarma
- Wake Forest University School of Medicine, Winston-Salem, NC, United States
- Department of Neurology, Atrium Health Wake Forest Baptist, Winston-Salem, NC, United States
- Anand Karthik Sarma,
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Hellas JA, Andrew RD. Neuronal Swelling: A Non-osmotic Consequence of Spreading Depolarization. Neurocrit Care 2021; 35:112-134. [PMID: 34498208 PMCID: PMC8536653 DOI: 10.1007/s12028-021-01326-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 08/04/2021] [Indexed: 01/22/2023]
Abstract
An acute reduction in plasma osmolality causes rapid uptake of water by astrocytes but not by neurons, whereas both cell types swell as a consequence of lost blood flow (ischemia). Either hypoosmolality or ischemia can displace the brain downwards, potentially causing death. However, these disorders are fundamentally different at the cellular level. Astrocytes osmotically swell or shrink because they express functional water channels (aquaporins), whereas neurons lack functional aquaporins and thus maintain their volume. Yet both neurons and astrocytes immediately swell when blood flow to the brain is compromised (cytotoxic edema) as following stroke onset, sudden cardiac arrest, or traumatic brain injury. In each situation, neuronal swelling is the direct result of spreading depolarization (SD) generated when the ATP-dependent sodium/potassium ATPase (the Na+/K+ pump) is compromised. The simple, and incorrect, textbook explanation for neuronal swelling is that increased Na+ influx passively draws Cl- into the cell, with water following by osmosis via some unknown conduit. We first review the strong evidence that mammalian neurons resist volume change during acute osmotic stress. We then contrast this with their dramatic swelling during ischemia. Counter-intuitively, recent research argues that ischemic swelling of neurons is non-osmotic, involving ion/water cotransporters as well as at least one known amino acid water pump. While incompletely understood, these mechanisms argue against the dogma that neuronal swelling involves water uptake driven by an osmotic gradient with aquaporins as the conduit. Promoting clinical recovery from neuronal cytotoxic edema evoked by spreading depolarizations requires a far better understanding of molecular water pumps and ion/water cotransporters that act to rebalance water shifts during brain ischemia.
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Affiliation(s)
- Julia A Hellas
- Center for Neuroscience Studies, Queen's University, Kingston, ON, K7L 3N6, Canada.
| | - R David Andrew
- Center for Neuroscience Studies, Queen's University, Kingston, ON, K7L 3N6, Canada
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Yu X, Zhang R, Wei C, Gao Y, Yu Y, Wang L, Jiang J, Zhang X, Li J, Chen X. MCT2 overexpression promotes recovery of cognitive function by increasing mitochondrial biogenesis in a rat model of stroke. Anim Cells Syst (Seoul) 2021; 25:93-101. [PMID: 34234890 PMCID: PMC8118516 DOI: 10.1080/19768354.2021.1915379] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 02/07/2021] [Accepted: 03/26/2021] [Indexed: 10/27/2022] Open
Abstract
Monocarboxylate transporter 2 (MCT2) is the predominant monocarboxylate transporter expressed by neurons. MCT2 plays an important role in brain energy metabolism. Stroke survivors are at high risk of cognitive impairment. We reported previously that stroke-induced cognitive impairment was related to impaired energy metabolism. In the present study, we report that cognitive function was impaired after stroke in rats. We found that MCT2 expression, but not that of MCT1 or MCT4, was markedly decreased in the rat hippocampus at 7 and 28 days after transient middle cerebral artery occlusion (tMCAO). Moreover, MCT2 overexpression promoted recovery of cognitive function after stroke. The molecular mechanism underlying these effects may be related to an increase in adenosine monophosphate-activated protein kinase-mediated mitochondrial biogenesis induced by overexpression of MCT2. Our findings suggest that MCT2 activation ameliorates cognitive impairment after stroke.
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Affiliation(s)
- Xiaorong Yu
- Department of Neurology, The Affiliated Jiangning Hospital with Nanjing Medical University, Nanjing, People's Republic of China
| | - Rui Zhang
- Department of Neurology, The Affiliated Jiangning Hospital with Nanjing Medical University, Nanjing, People's Republic of China
| | - Cunsheng Wei
- Department of Neurology, The Affiliated Jiangning Hospital with Nanjing Medical University, Nanjing, People's Republic of China
| | - Yuanyuan Gao
- Department of General Practice, The Affiliated Jiangning Hospital with Nanjing Medical University, Nanjing, People's Republic of China
| | - Yanhua Yu
- Department of Neurology, The Affiliated Jiangning Hospital with Nanjing Medical University, Nanjing, People's Republic of China
| | - Lin Wang
- Department of Neurology, The Affiliated Jiangning Hospital with Nanjing Medical University, Nanjing, People's Republic of China
| | - Junying Jiang
- Department of Neurology, The Affiliated Jiangning Hospital with Nanjing Medical University, Nanjing, People's Republic of China
| | - Xuemei Zhang
- Department of Neurology, The Affiliated Jiangning Hospital with Nanjing Medical University, Nanjing, People's Republic of China
| | - Junrong Li
- Department of Neurology, The Affiliated Jiangning Hospital with Nanjing Medical University, Nanjing, People's Republic of China
| | - Xuemei Chen
- Department of Neurology, The Affiliated Jiangning Hospital with Nanjing Medical University, Nanjing, People's Republic of China
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7
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Felmlee MA, Jones RS, Rodriguez-Cruz V, Follman KE, Morris ME. Monocarboxylate Transporters (SLC16): Function, Regulation, and Role in Health and Disease. Pharmacol Rev 2020; 72:466-485. [PMID: 32144120 DOI: 10.1124/pr.119.018762] [Citation(s) in RCA: 168] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The solute carrier family 16 (SLC16) is comprised of 14 members of the monocarboxylate transporter (MCT) family that play an essential role in the transport of important cell nutrients and for cellular metabolism and pH regulation. MCTs 1-4 have been extensively studied and are involved in the proton-dependent transport of L-lactate, pyruvate, short-chain fatty acids, and monocarboxylate drugs in a wide variety of tissues. MCTs 1 and 4 are overexpressed in a number of cancers, and current investigations have focused on transporter inhibition as a novel therapeutic strategy in cancers. MCT1 has also been used in strategies aimed at enhancing drug absorption due to its high expression in the intestine. Other MCT isoforms are less well characterized, but ongoing studies indicate that MCT6 transports xenobiotics such as bumetanide, nateglinide, and probenecid, whereas MCT7 has been characterized as a transporter of ketone bodies. MCT8 and MCT10 transport thyroid hormones, and recently, MCT9 has been characterized as a carnitine efflux transporter and MCT12 as a creatine transporter. Expressed at the blood brain barrier, MCT8 mutations have been associated with an X-linked intellectual disability, known as Allan-Herndon-Dudley syndrome. Many MCT isoforms are associated with hormone, lipid, and glucose homeostasis, and recent research has focused on their potential roles in disease, with MCTs representing promising novel therapeutic targets. This review will provide a summary of the current literature focusing on the characterization, function, and regulation of the MCT family isoforms and on their roles in drug disposition and in health and disease. SIGNIFICANCE STATEMENT: The 14-member solute carrier family 16 of monocarboxylate transporters (MCTs) plays a fundamental role in maintaining intracellular concentrations of a broad range of important endogenous molecules in health and disease. MCTs 1, 2, and 4 (L-lactate transporters) are overexpressed in cancers and represent a novel therapeutic target in cancer. Recent studies have highlighted the importance of MCTs in glucose, lipid, and hormone homeostasis, including MCT8 in thyroid hormone brain uptake, MCT12 in carnitine transport, and MCT11 in type 2 diabetes.
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Affiliation(s)
- Melanie A Felmlee
- Department of Pharmaceutics and Medicinal Chemistry, Thomas J. Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, California (M.A.F.); Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, State University of New York, Buffalo, New York (R.S.J., V.R.-C., M.E.M.); and Certara Strategic Consulting, Certara USA, Princeton, New Jersey (K.E.F.)
| | - Robert S Jones
- Department of Pharmaceutics and Medicinal Chemistry, Thomas J. Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, California (M.A.F.); Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, State University of New York, Buffalo, New York (R.S.J., V.R.-C., M.E.M.); and Certara Strategic Consulting, Certara USA, Princeton, New Jersey (K.E.F.)
| | - Vivian Rodriguez-Cruz
- Department of Pharmaceutics and Medicinal Chemistry, Thomas J. Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, California (M.A.F.); Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, State University of New York, Buffalo, New York (R.S.J., V.R.-C., M.E.M.); and Certara Strategic Consulting, Certara USA, Princeton, New Jersey (K.E.F.)
| | - Kristin E Follman
- Department of Pharmaceutics and Medicinal Chemistry, Thomas J. Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, California (M.A.F.); Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, State University of New York, Buffalo, New York (R.S.J., V.R.-C., M.E.M.); and Certara Strategic Consulting, Certara USA, Princeton, New Jersey (K.E.F.)
| | - Marilyn E Morris
- Department of Pharmaceutics and Medicinal Chemistry, Thomas J. Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, California (M.A.F.); Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, State University of New York, Buffalo, New York (R.S.J., V.R.-C., M.E.M.); and Certara Strategic Consulting, Certara USA, Princeton, New Jersey (K.E.F.)
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Zhang Y, Cao H, Qiu X, Xu D, Chen Y, Barnes GN, Tu Y, Gyabaah AT, Gharbal AHAA, Peng C, Cai J, Cai X. Neuroprotective Effects of Adenosine A1 Receptor Signaling on Cognitive Impairment Induced by Chronic Intermittent Hypoxia in Mice. Front Cell Neurosci 2020; 14:202. [PMID: 32733207 PMCID: PMC7363980 DOI: 10.3389/fncel.2020.00202] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 06/09/2020] [Indexed: 12/18/2022] Open
Abstract
Obstructive sleep apnea-hypopnea syndrome (OSAHS) is a breathing disorder associated with cognitive impairment. However, the mechanisms leading to cognitive deficits in OSAHS remain uncertain. In this study, a mouse model of chronic intermittent hypoxia (CIH) exposures were applied for simulating the deoxygenation-reoxygenation events occurring in OSAHS. The conventional adenosine A1 receptor gene (A1R) knockout mice and the A1R agonist CCPA- or antagonist DPCPX-administrated mice were utilized to determine the precise function of A1R signaling in the process of OSAHS-relevant cognitive impairment. We demonstrated that CIH induced morphological changes and apoptosis in hippocampal neurons. Further, CIH blunted hippocampal long-term potentiation (LTP) and resulted in learning/memory impairment. Disruption of adenosine A1R exacerbated morphological, cellular, and functional damage induced by CIH. In contrast, activation of adenosine A1R signaling reduced morphological changes and apoptosis of hippocampal neurons, promoted LTP, and enhanced learning and memory. A1Rs may up-regulate protein kinase C (PKC) and its subtype PKC-ζ through the activation of Gα(i) improve spatial learning and memory disorder induced by CIH in mice. Taken together, A1R signaling plays a neuroprotective role in CIH-induced cognitive dysfunction and pathological changes in the hippocampus.
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Affiliation(s)
- Yichun Zhang
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, China
| | - Hongchao Cao
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, China.,Department of Internal Medicine, Hwa Mei Hospital, University of Chinese Academy of Sciences (Ningbo No. 2 Hospital), Ningbo, China
| | - Xuehao Qiu
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, China
| | - Danfen Xu
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, China
| | - Yifeng Chen
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, China
| | - Gregory N Barnes
- Department of Neurology, University of Louisville School of Medicine, Louisville, KY, United States.,Department of Pediatrics, Pediatric Research Institute, University of Louisville School of Medicine, Louisville, KY, United States
| | - Yunjia Tu
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, China
| | - Adwoa Takyiwaa Gyabaah
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, China
| | | | - Chenlei Peng
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, China.,Department of Internal Medicine, Hwa Mei Hospital, University of Chinese Academy of Sciences (Ningbo No. 2 Hospital), Ningbo, China
| | - Jun Cai
- Department of Pediatrics, Pediatric Research Institute, University of Louisville School of Medicine, Louisville, KY, United States
| | - Xiaohong Cai
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, China
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Wang H, Shi X, Schenck H, Hall JR, Ross SE, Kline GP, Chen S, Mallet RT, Chen P. Intermittent Hypoxia Training for Treating Mild Cognitive Impairment: A Pilot Study. Am J Alzheimers Dis Other Demen 2020; 35:1533317519896725. [PMID: 31902230 PMCID: PMC10624018 DOI: 10.1177/1533317519896725] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Although intermittent hypoxia training (IHT) has proven effective against various clinical disorders, its impact on mild cognitive impairment (MCI) is unknown. This pilot study examined IHT's safety and therapeutic efficacy in elderly patients with amnestic MCI (aMCI). Seven patients with aMCI (age 69 ± 3 years) alternately breathed 10% O2 and room-air, each 5 minutes, for 8 cycles/session, 3 sessions/wk for 8 weeks. The patients' resting arterial pressures fell by 5 to 7 mm Hg (P < .05) and cerebral tissue oxygenation increased (P < .05) following IHT. Intermittent hypoxia training enhanced hypoxemia-induced cerebral vasodilation (P < .05) and improved mini-mental state examination and digit span scores from 25.7 ± 0.4 to 27.7 ± 0.6 (P = .038) and from 24.7 ± 1.2 to 26.1 ± 1.3 (P = .047), respectively. California verbal learning test score tended to increase (P = .102), but trail making test-B and controlled oral word association test scores were unchanged. Adaptation to moderate IHT may enhance cerebral oxygenation and hypoxia-induced cerebrovasodilation while improving short-term memory and attention in elderly patients with aMCI.
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Affiliation(s)
- Hong Wang
- Departments of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, USA
- Shanghai University of Medicine & Health Sciences, Shanghai, China
| | - Xiangrong Shi
- Departments of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, USA
- Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Hannah Schenck
- Departments of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - James R. Hall
- Departments of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, USA
- Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Sarah E. Ross
- Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, TX, USA
- Department of Internal Medicine, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Geoffrey P. Kline
- Department of Internal Medicine, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Shande Chen
- Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Robert T. Mallet
- Departments of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Peijie Chen
- Shanghai University of Sport, Shanghai, China
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10
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Liu W, Zhang W, Wang T, Wu J, Zhong X, Gao K, Liu Y, He X, Zhou Y, Wang H, Zeng H. Obstructive sleep apnea syndrome promotes the progression of aortic dissection via a ROS- HIF-1α-MMPs associated pathway. Int J Biol Sci 2019; 15:2774-2782. [PMID: 31853217 PMCID: PMC6909961 DOI: 10.7150/ijbs.34888] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 08/20/2019] [Indexed: 01/25/2023] Open
Abstract
Aims: Obstructive sleep apnea syndrome (OSAS) has been increasingly recognized as an independent risk factor for aortic dissection (AD) and it is strongly associated with the extent of intermittent hypoxia and re-oxygenation (IH). This study aimed to clarify role of ROS- HIF-1α-MMPs pathway in the pathogenesis of AD and whether the HIF-1α inhibitor attenuates AD formation. Methods and results: 8-week-old male ApoE-/- mice were given β-aminopropionitrile at a concentration of 0.1 % for 3 weeks and infused via osmotic mini pumps with either saline or 2,500 ng/min/kg angiotensin II (Ang II) for 2 weeks. To mimic the OSAS, one group was exposed to IH, which consisted of alternating cycles of 20.9% O2/8% O2 FiO2 (30 episodes per hour) with 20 s at the nadir FiO2 during the 12-h light phase, 2 weeks before Ang II infusion. After Ang II infusion, we assessed remodeling in the aorta by echocardiography, histological and immunohistochemical analysis. IH treatment resulted in significant enlargement of the luminal area, destruction of the media, marked thickening of the adventitia, higher incidence of AD formation and lower survival rate in compared with the Ang II only group. Moreover, IH exposure markedly increased the aortic ROS production and subsequent HIF-1α expression, which in turn promoted the expressions of VEGF, MMP2 and MMP9 and finally leading to the progression of AD. Besides, in vitro study confirmed that IH induced HIF-1α expression plays an important role in the induction of MMPs and that is regulated by the PI3K/AKT/FRAP pathway. Intriguingly, a selective HIF-1α inhibitor KC7F2 could significantly ameliorate IH exposure induced aforementioned deleterious effects in vitro and in vivo.Conclusion: OSAS induced IH can promote the occurrence and progression of AD via a ROS- HIF-1α-MMPs associated pathway. The selective HIF-1α inhibitor KC7F2 could be a novel therapeutic agent for AD patient with OSAS.
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Affiliation(s)
- Wanjun Liu
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, PR China
- Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan, 430030, PR China
| | - Wenjun Zhang
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, PR China
- Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan, 430030, PR China
| | - Tao Wang
- Department of Cardiology, Affiliated Hospital of Weifang Medical University, Weifang, Shandong, 261000, PR China
| | - Jinhua Wu
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, PR China
- Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan, 430030, PR China
| | - Xiaodan Zhong
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, PR China
- Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan, 430030, PR China
| | - Kun Gao
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, PR China
- Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan, 430030, PR China
| | - Yujian Liu
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, PR China
- Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan, 430030, PR China
| | - Xingwei He
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, PR China
- Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan, 430030, PR China
| | - Yiwu Zhou
- Department of Forensic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, PR China
| | - Hongjie Wang
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, PR China
- Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan, 430030, PR China
- ✉ Corresponding author: Hongjie Wang, , Tel. +86-27-8369-3794, Fax: +86-27-8366-3186; Hesong Zeng, , Tel. +86-27-8369-2850, Fax: +86-27-8366-3186
| | - Hesong Zeng
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, PR China
- Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan, 430030, PR China
- ✉ Corresponding author: Hongjie Wang, , Tel. +86-27-8369-3794, Fax: +86-27-8366-3186; Hesong Zeng, , Tel. +86-27-8369-2850, Fax: +86-27-8366-3186
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11
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Poonit ND, Zhang YC, Ye CY, Cai HL, Yu CY, Li T, Cai XH. Chronic intermittent hypoxia exposure induces kidney injury in growing rats. Sleep Breath 2017; 22:453-461. [PMID: 29124628 DOI: 10.1007/s11325-017-1587-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 09/21/2017] [Accepted: 10/20/2017] [Indexed: 11/29/2022]
Abstract
OBJECTIVE The objectives of this paper are to examine the effect of chronic intermittent hypoxia (CIH) on the morphological changes in the kidney of growing rats and to explore the mechanisms underlying the CIH-induced renal damage. METHODS Forty Sprague-Dawley rats were randomly divided into two groups: 2 and 4 weeks CIH groups (2IH, 4IH), and in the control group 2 and 4 weeks air-stimulated groups (2C, 4C), with 10 rats in each group. Pathological changes of renal tissue were observed by HE staining, PAS staining, and Masson staining. Real-time PCR method was used to detect the mRNA expression of HIF-1α, CuZnSOD/ZnSOD, and MnSOD in renal tissue. RESULTS (1) Intermittent hypoxia (IH) caused morphological damage in the kidney. Hypertrophy of epithelial cells in the kidney tubules and dilation in the glomeruli were observed under light microscope in HE and PAS stain, especially in 4IH group. Masson staining showed no significant fibrotic response in the IH groups. (2) Compared with the corresponding control groups, the levels of serum SOD were significantly lower in CIH groups, and especially in 4IH group. The mRNA expression of Cu/ZnSOD and MnSOD in CIH groups decreased significantly as compared to control groups. The mRNA levels of HIF-1α in the kidney were significantly higher in CIH groups than those in the corresponding control groups. CONCLUSION Oxidative stress played a critical role in renal damage by up-regulating HIF-1α transcription and down-regulating Cu/ZnSOD and MnSOD transcription after chronic intermittent hypoxia exposure in growing rats.
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Affiliation(s)
- Neha-Devi Poonit
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 109 Xueyuan Western Road, Wenzhou, Zhejiang, 325027, People's Republic of China
| | - Yi-Chun Zhang
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 109 Xueyuan Western Road, Wenzhou, Zhejiang, 325027, People's Republic of China
| | - Chu-Yuan Ye
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 109 Xueyuan Western Road, Wenzhou, Zhejiang, 325027, People's Republic of China
| | - Hui-Lin Cai
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 109 Xueyuan Western Road, Wenzhou, Zhejiang, 325027, People's Republic of China
| | - Chen-Yi Yu
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 109 Xueyuan Western Road, Wenzhou, Zhejiang, 325027, People's Republic of China
| | - Ting Li
- The Children's Hospital, Zhejiang University School Of Medicine, Hangzhou, 310000, China
| | - Xiao-Hong Cai
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 109 Xueyuan Western Road, Wenzhou, Zhejiang, 325027, People's Republic of China. .,Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325027, China.
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12
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Yoo DY, Park JH, Lee KY, Kwon HJ, Jung HY, Kim JW, Kim DW, Choi JH, Moon SM, Yoon YS, Won MH, Hwang IK. Temporal and spatial changes of monocarboxylate transporter 4 expression in the hippocampal CA1 region following transient forebrain ischemia in the Mongolian gerbil. Mol Med Rep 2017; 15:4225-4230. [PMID: 28440446 DOI: 10.3892/mmr.2017.6508] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 02/13/2017] [Indexed: 11/06/2022] Open
Abstract
Transient forebrain ischemia depletes glucose and oxygen levels in the brain. In this pathological condition, lactate serves an important role in cellular metabolism as the end product of glycolysis. The present study investigated the expression of monocarboxylate transporter 4 (MCT4) in lactate metabolism in the hippocampal CA1 region following induction of transient forebrain ischemia. MCT4 immunoreactivity was detected in CA1 pyramidal cells of the sham-operated group. Animals from the ischemic group exhibited a transient decrease in MCT4 immunoreactivity in the CA1 region between 30 min and 3 h following ischemia compared with the sham‑operated group. The initial decrease in immunoreactivity observed between 30 min and 3 h following ischemia was followed by an increase at 2 days after the treatment. A significant increase in MCT4 immunoreactivity levels was observed 2 days after ischemia compared with the sham‑operated group. Limited MCT4 immunoreactivity was observed in the pyramidal neurons 3 days after ischemia. At 4‑10 days after ischemia, MCT4 immunoreactivity was detected in the strata radiatum, oriens and pyramidale. Furthermore, MCT4 immunoreactivity levels in the CA1 region exhibited a time‑dependent increase following ischemia. The results indicated that there were transient alterations observed in the localization of MCT4 following the induction of ischemia, and further studies are required to investigate the association between MCT4 expression and lactate metabolism in providing energy to the post‑ischemic brain.
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Affiliation(s)
- Dae Young Yoo
- Department of Anatomy and Cell Biology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
| | - Joon Ha Park
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Kwon Young Lee
- Department of Anatomy, College of Veterinary Medicine, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Hyun Jung Kwon
- Department of Biochemistry and Molecular Biology, Research Institute of Oral Sciences, College of Dentistry, Gangneung‑Wonju National University, Gangneung, Gangwon 25457, Republic of Korea
| | - Hyo Young Jung
- Department of Anatomy and Cell Biology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
| | - Jong Whi Kim
- Department of Anatomy and Cell Biology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
| | - Dae Won Kim
- Department of Biochemistry and Molecular Biology, Research Institute of Oral Sciences, College of Dentistry, Gangneung‑Wonju National University, Gangneung, Gangwon 25457, Republic of Korea
| | - Jung Hoon Choi
- Department of Anatomy, College of Veterinary Medicine, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Seung Myung Moon
- Department of Neurosurgery, Dongtan Sacred Heart Hospital, College of Medicine, Hallym University, Hwaseong, Gyeonggi 18450, Republic of Korea
| | - Yeo Sung Yoon
- Department of Anatomy and Cell Biology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
| | - Moo-Ho Won
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - In Koo Hwang
- Department of Anatomy and Cell Biology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
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13
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Scott GF, Nguyen AQ, Cherry BH, Hollrah RA, Salinas I, Williams AG, Ryou MG, Mallet RT. Featured Article: Pyruvate preserves antiglycation defenses in porcine brain after cardiac arrest. Exp Biol Med (Maywood) 2017; 242:1095-1103. [PMID: 28361585 DOI: 10.1177/1535370217703353] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Cardiac arrest (CA) and cardiocerebral resuscitation (CCR)-induced ischemia-reperfusion imposes oxidative and carbonyl stress that injures the brain. The ischemic shift to anaerobic glycolysis, combined with oxyradical inactivation of glyceraldehyde 3-phosphate dehydrogenase (GAPDH), provokes excessive formation of the powerful glycating agent, methylglyoxal. The glyoxalase (GLO) system, comprising the enzymes glyoxalase 1 (GLO1) and GLO2, utilizes reduced glutathione (GSH) supplied by glutathione reductase (GR) to detoxify methylglyoxal resulting in reduced protein glycation. Pyruvate, a natural antioxidant that augments GSH redox status, could sustain the GLO system in the face of ischemia-reperfusion. This study assessed the impact of CA-CCR on the cerebral GLO system and pyruvate's ability to preserve this neuroprotective system following CA. Domestic swine were subjected to 10 min CA, 4 min closed-chest CCR, defibrillation and 4 h recovery, or to a non-CA sham protocol. Sodium pyruvate or NaCl control was infused (0.1 mmol/kg/min, intravenous) throughout CCR and the first 60 min recovery. Protein glycation, GLO1 content, and activities of GLO1, GR, and GAPDH were analyzed in frontal cortex biopsied at 4 h recovery. CA-CCR produced marked protein glycation which was attenuated by pyruvate treatment. GLO1, GR, and GAPDH activities fell by 86, 55, and 30%, respectively, after CA-CCR with NaCl infusion. Pyruvate prevented inactivation of all three enzymes. CA-CCR sharply lowered GLO1 monomer content with commensurate formation of higher molecular weight immunoreactivity; pyruvate preserved GLO1 monomers. Thus, ischemia-reperfusion imposed by CA-CCR disabled the brain's antiglycation defenses. Pyruvate preserved these enzyme systems that protect the brain from glycation stress. Impact statement Recent studies have demonstrated a pivotal role of protein glycation in brain injury. Methylglyoxal, a by-product of glycolysis and a powerful glycating agent in brain, is detoxified by the glutathione-catalyzed glyoxalase (GLO) system, but the impact of cardiac arrest (CA) and cardiocerebral resuscitation (CCR) on the brain's antiglycation defenses is unknown. This study in a swine model of CA and CCR demonstrated for the first time that the intense cerebral ischemia-reperfusion imposed by CA-resuscitation disabled glyoxalase-1 and glutathione reductase (GR), the source of glutathione for methylglyoxal detoxification. Moreover, intravenous administration of pyruvate, a redox-active intermediary metabolite and antioxidant in brain, prevented inactivation of glyoxalase-1 and GR and blunted protein glycation in cerebral cortex. These findings in a large mammal are first evidence of GLO inactivation and the resultant cerebral protein glycation after CA-resuscitation, and identify novel actions of pyruvate to minimize protein glycation in postischemic brain.
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Affiliation(s)
- Gary F Scott
- 1 Institute for Cardiovascular and Metabolic Diseases, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Anh Q Nguyen
- 1 Institute for Cardiovascular and Metabolic Diseases, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Brandon H Cherry
- 1 Institute for Cardiovascular and Metabolic Diseases, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Roger A Hollrah
- 1 Institute for Cardiovascular and Metabolic Diseases, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Isabella Salinas
- 2 Department of Biological Sciences, St. Mary's University, San Antonio, TX 78228, USA
| | - Arthur G Williams
- 1 Institute for Cardiovascular and Metabolic Diseases, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Myoung-Gwi Ryou
- 3 Department of Medical Laboratory Sciences, Tarleton State University, Fort Worth, TX 76107, USA
| | - Robert T Mallet
- 1 Institute for Cardiovascular and Metabolic Diseases, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
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14
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Gemel J, Su Z, Gileles-Hillel A, Khalyfa A, Gozal D, Beyer EC. Intermittent hypoxia causes NOX2-dependent remodeling of atrial connexins. BMC Cell Biol 2017; 18:7. [PMID: 28124622 PMCID: PMC5267331 DOI: 10.1186/s12860-016-0117-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Obstructive sleep apnea has been linked to the development of heart disease and arrhythmias, including atrial fibrillation. Since altered conduction through gap junction channels can contribute to the pathogenesis of such arrhythmias, we examined the abundance and distributions of the major cardiac gap junction proteins, connexin40 (Cx40) and connexin43 (Cx43) in mice treated with sleep fragmentation or intermittent hypoxia (IH) as animal models of the components of obstructive sleep apnea. RESULTS Wild type C57BL/6 mice or mice lacking NADPH 2 (NOX2) oxidase activity (gp91phox(-/Y)) were exposed to room air or to SF or IH for 6 weeks. Then, the mice were sacrificed, and atria and ventricles were immediately dissected. The abundances of Cx40 or Cx43 in atria and ventricles were unaffected by SF. In contrast, immunoblots showed that the abundance of atrial Cx40 and Cx43 and ventricular Cx43 were reduced in mice exposed to IH. qRT-PCR demonstrated significant reductions of atrial Cx40 and Cx43 mRNAs. Immunofluorescence microscopy revealed that the abundance and size of gap junctions containing Cx40 or Cx43 were reduced in atria by IH treatment of mice. However, no changes of connexin abundance or gap junction size/abundance were observed in IH-treated NOX2-null mice. CONCLUSIONS These results demonstrate that intermittent hypoxia (but not sleep fragmentation) causes reductions and remodeling of atrial Cx40 and Cx43. These alterations may contribute to the substrate for atrial fibrillation that develops in response to obstructive sleep apnea. Moreover, these connexin changes are likely generated in response to reactive oxygen species generated by NOX2.
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Affiliation(s)
- Joanna Gemel
- Department of Pediatrics, University of Chicago, 900 E. 57th St. KCBD 5152, Chicago, IL, 60637, USA
| | - Zihan Su
- Present address: Williams College, Williamstown, MA, USA
| | - Alex Gileles-Hillel
- Present address: Department of Pediatrics, Hadassah-Hebrew University Medical Center, Mt. Scopus, Jerusalem, Israel
| | - Abdelnaby Khalyfa
- Department of Pediatrics, University of Chicago, 900 E. 57th St. KCBD 5152, Chicago, IL, 60637, USA
| | - David Gozal
- Department of Pediatrics, University of Chicago, 900 E. 57th St. KCBD 5152, Chicago, IL, 60637, USA
| | - Eric C Beyer
- Department of Pediatrics, University of Chicago, 900 E. 57th St. KCBD 5152, Chicago, IL, 60637, USA.
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15
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Hoshino D, Setogawa S, Kitaoka Y, Masuda H, Tamura Y, Hatta H, Yanagihara D. Exercise-induced expression of monocarboxylate transporter 2 in the cerebellum and its contribution to motor performance. Neurosci Lett 2016; 633:1-6. [DOI: 10.1016/j.neulet.2016.09.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 09/05/2016] [Accepted: 09/09/2016] [Indexed: 12/18/2022]
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16
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Jha MK, Lee IK, Suk K. Metabolic reprogramming by the pyruvate dehydrogenase kinase-lactic acid axis: Linking metabolism and diverse neuropathophysiologies. Neurosci Biobehav Rev 2016; 68:1-19. [PMID: 27179453 DOI: 10.1016/j.neubiorev.2016.05.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 04/11/2016] [Accepted: 05/09/2016] [Indexed: 12/12/2022]
Abstract
Emerging evidence indicates that there is a complex interplay between metabolism and chronic disorders in the nervous system. In particular, the pyruvate dehydrogenase (PDH) kinase (PDK)-lactic acid axis is a critical link that connects metabolic reprogramming and the pathophysiology of neurological disorders. PDKs, via regulation of PDH complex activity, orchestrate the conversion of pyruvate either aerobically to acetyl-CoA, or anaerobically to lactate. The kinases are also involved in neurometabolic dysregulation under pathological conditions. Lactate, an energy substrate for neurons, is also a recently acknowledged signaling molecule involved in neuronal plasticity, neuron-glia interactions, neuroimmune communication, and nociception. More recently, the PDK-lactic acid axis has been recognized to modulate neuronal and glial phenotypes and activities, contributing to the pathophysiologies of diverse neurological disorders. This review covers the recent advances that implicate the PDK-lactic acid axis as a novel linker of metabolism and diverse neuropathophysiologies. We finally explore the possibilities of employing the PDK-lactic acid axis and its downstream mediators as putative future therapeutic strategies aimed at prevention or treatment of neurological disorders.
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Affiliation(s)
- Mithilesh Kumar Jha
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 PLUS KNU Biomedical Convergence Program, Kyungpook National University School of Medicine, Daegu, Republic of Korea; Department of Neurology, Division of Neuromuscular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - In-Kyu Lee
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Kyoungho Suk
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 PLUS KNU Biomedical Convergence Program, Kyungpook National University School of Medicine, Daegu, Republic of Korea.
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17
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Rosafio K, Castillo X, Hirt L, Pellerin L. Cell-specific modulation of monocarboxylate transporter expression contributes to the metabolic reprograming taking place following cerebral ischemia. Neuroscience 2016; 317:108-20. [DOI: 10.1016/j.neuroscience.2015.12.052] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 12/17/2015] [Accepted: 12/29/2015] [Indexed: 01/23/2023]
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18
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Sapin E, Peyron C, Roche F, Gay N, Carcenac C, Savasta M, Levy P, Dematteis M. Chronic Intermittent Hypoxia Induces Chronic Low-Grade Neuroinflammation in the Dorsal Hippocampus of Mice. Sleep 2015; 38:1537-46. [PMID: 26085297 DOI: 10.5665/sleep.5042] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Indexed: 12/21/2022] Open
Abstract
STUDY OBJECTIVES Obstructive sleep apnea (OSA) induces cognitive impairment that involves intermittent hypoxia (IH). Because OSA is recognized as a low-grade systemic inflammatory disease and only some patients develop cognitive deficits, we investigated whether IH-related brain consequences shared similar pathophysiology and required additional factors such as systemic inflammation to develop. DESIGN Nine-week-old male C57BL/6J mice were exposed to 1 day, 6 or 24 w of IH (alternating 21-5% FiO2 every 30 sec, 8 h/day) or normoxia. Microglial changes were assessed in the functionally distinct dorsal (dH) and ventral (vH) regions of the hippocampus using Iba1 immunolabeling. Then the study concerned dH, as vH only tended to be lately affected. Seven proinflammatory and anti-inflammatory cytokine messenger RNA (mRNA) were assessed at all time points using semiquantitative real-time reverse transcription polymerase chain reaction (RT-PCR). Similar mRNA analysis was performed after 6 w IH or normoxia associated for the past 3 w with repeated intraperitoneal low-dose lipopolysaccharide or saline. MEASUREMENTS AND RESULTS Chronic (6, 24 w) but not acute IH induced significant microglial changes in dH only, including increased density and morphological features of microglia priming. In dH, acute but not chronic IH increased IL-1β and RANTES/CCL5 mRNA, whereas the other cytokines remained unchanged. In contrast, chronic IH plus lipopolysaccharide increased interleukin (IL)-6 and IL10 mRNA whereas lipopolysaccharide alone did not affect these cytokines. CONCLUSION The obstructive sleep apnea component intermittent hypoxia (IH) causes low-grade neuroinflammation in the dorsal hippocampus of mice, including early but transient cytokine elevations, delayed but long-term microglial changes, and cytokine response alterations to lipopolysaccharide inflammatory challenge. These changes may contribute to IH-induced cognitive impairment and pathological brain aging.
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Affiliation(s)
- Emilie Sapin
- Université Grenoble Alpes, Grenoble, F-38042, France.,INSERM U1042, Laboratoire HP2, Grenoble, F-38042, France
| | - Christelle Peyron
- INSERM U1028, CNRS UMR 5292, Lyon Neuroscience Research Center, Team SLEEP, F-69372, France.,Université Claude Bernard Lyon 1, Lyon, F-69372, France
| | - Frédéric Roche
- CHU, Hôpital Nord, Service de Physiologie Clinique et de l'Exercice, Saint-Etienne, F-42270, France.,Université Jean Monnet, Saint-Etienne, F-42023, France
| | - Nadine Gay
- INSERM U1028, CNRS UMR 5292, Lyon Neuroscience Research Center, Team SLEEP, F-69372, France.,Université Claude Bernard Lyon 1, Lyon, F-69372, France
| | - Carole Carcenac
- Université Grenoble Alpes, Grenoble, F-38042, France.,INSERM U836, Grenoble Institut des Neurosciences, équipe 10, Grenoble, F-38042, France
| | - Marc Savasta
- Université Grenoble Alpes, Grenoble, F-38042, France.,INSERM U836, Grenoble Institut des Neurosciences, équipe 10, Grenoble, F-38042, France
| | - Patrick Levy
- Université Grenoble Alpes, Grenoble, F-38042, France.,INSERM U1042, Laboratoire HP2, Grenoble, F-38042, France.,CHU, Hôpital Michallon, Laboratoires du Sommeil et EFCR, Grenoble F-38043, France
| | - Maurice Dematteis
- Université Grenoble Alpes, Grenoble, F-38042, France.,INSERM U1042, Laboratoire HP2, Grenoble, F-38042, France.,CHU, Hôpital Michallon, Addictologie, Pôle Pluridisciplinaire de Médecine, Grenoble F-38043, France
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19
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Mifflin S, Cunningham JT, Toney GM. Neurogenic mechanisms underlying the rapid onset of sympathetic responses to intermittent hypoxia. J Appl Physiol (1985) 2015; 119:1441-8. [PMID: 25997944 DOI: 10.1152/japplphysiol.00198.2015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 05/19/2015] [Indexed: 11/22/2022] Open
Abstract
Sleep apnea (SA) leads to metabolic abnormalities and cardiovascular dysfunction. Rodent models of nocturnal intermittent hypoxia (IH) are used to mimic arterial hypoxemias that occur during SA. This mini-review focuses on our work examining central nervous system (CNS) mechanisms whereby nocturnal IH results in increased sympathetic nerve discharge (SND) and hypertension (HTN) that persist throughout the 24-h diurnal period. Within the first 1-2 days of IH, arterial pressure (AP) increases even during non-IH periods of the day. Exposure to IH for 7 days biases nucleus tractus solitarius (NTS) neurons receiving arterial chemoreceptor inputs toward increased discharge, providing a substrate for persistent activation of sympathetic outflow. IH HTN is blunted by manipulations that reduce angiotensin II (ANG II) signaling within the forebrain lamina terminalis suggesting that central ANG II supports persistent IH HTN. Inhibition of the hypothalamic paraventricular nucleus (PVN) reduces ongoing SND and acutely lowers AP in IH-conditioned animals. These findings support a role for the PVN, which integrates information ascending from NTS and descending from the lamina terminalis, in sustaining IH HTN. In summary, our findings indicate that IH rapidly and persistently activates a central circuit that includes the NTS, forebrain lamina terminalis, and the PVN. Our working model holds that NTS neuromodulation increases transmission of arterial chemoreceptor inputs, increasing SND via connections with PVN and rostral ventrolateral medulla. Increased circulating ANG II sensed by the lamina terminalis generates yet another excitatory drive to PVN. Together with adaptations intrinsic to the PVN, these responses to IH support rapid onset neurogenic HTN.
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Affiliation(s)
- Steve Mifflin
- Department of Integrative Physiology and Anatomy, Cardiovascular Research Institute, University of North Texas Health Science Center, Fort Worth, Texas; and
| | - J Thomas Cunningham
- Department of Integrative Physiology and Anatomy, Cardiovascular Research Institute, University of North Texas Health Science Center, Fort Worth, Texas; and
| | - Glenn M Toney
- Department of Physiology, University of Texas Health Science Center, San Antonio, Texas
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Patyar S, Patyar RR. Correlation between Sleep Duration and Risk of Stroke. J Stroke Cerebrovasc Dis 2015; 24:905-11. [DOI: 10.1016/j.jstrokecerebrovasdis.2014.12.038] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 12/27/2014] [Accepted: 12/31/2014] [Indexed: 10/23/2022] Open
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21
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Li R, Luo X, Wu J, Thangthaeng N, Jung ME, Jing S, Li L, Ellis DZ, Liu L, Ding Z, Forster MJ, Yan LJ. Mitochondrial Dihydrolipoamide Dehydrogenase is Upregulated in Response to Intermittent Hypoxic Preconditioning. Int J Med Sci 2015; 12:432-40. [PMID: 26078703 PMCID: PMC4466405 DOI: 10.7150/ijms.11402] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Accepted: 05/13/2015] [Indexed: 01/06/2023] Open
Abstract
Intermittent hypoxia preconditioning (IHP) has been shown to protect neurons against ischemic stroke injury. Studying how proteins respond to IHP may identify targets that can help fight stroke. The objective of the present study was to investigate whether mitochondrial dihydrolipoamide dehydrogenase (DLDH) would respond to IHP and if so, whether such a response could be linked to neuroprotection in ischemic stroke injury. To do this, we subjected male rats to IHP for 20 days and measured the content and activity of DLDH as well as the three α-keto acid dehydrogenase complexes that contain DLDH. We also measured mitochondrial electron transport chain enzyme activities. Results show that DLDH content was indeed upregulated by IHP and this upregulation did not alter the activities of the three α-keto acid dehydrogenase complexes. Results also show that the activities of the five mitochondrial complexes (I-V) were not altered either by IHP. To investigate whether IHP-induced DLDH upregulation is linked to neuroprotection against ischemic stroke injury, we subjected both DLDH deficient mouse and DLDH transgenic mouse to stroke surgery followed by measurement of brain infarction volume. Results indicate that while mouse deficient in DLDH had exacerbated brain injury after stroke, mouse overexpressing human DLDH also showed increased brain injury after stroke. Therefore, the physiological significance of IHP-induced DLDH upregulation remains to be further investigated.
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Affiliation(s)
- Rongrong Li
- 1. Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA ; 2. Department of Anethesiology, the First Affiliated Hospital of Nanjing University, Nanjing, Jiangsu province, China, 210029
| | - Xiaoting Luo
- 1. Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA ; 3. Department of Biochemistry and Molecular Biology, Gannan Medical University, Ganzhou, Jiangxi province, China, 341000
| | - Jinzi Wu
- 1. Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Nopporn Thangthaeng
- 4. Department of Pharmacology and Neurosciences, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Marianna E Jung
- 4. Department of Pharmacology and Neurosciences, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Siqun Jing
- 1. Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA ; 5. College of Life Sciences and Technology, Xinjiang University, Urumqi, Xinjiang, China, 830046
| | - Linya Li
- 1. Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Dorette Z Ellis
- 1. Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Li Liu
- 6. Department of Geriatrics, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China 210029
| | - Zhengnian Ding
- 2. Department of Anethesiology, the First Affiliated Hospital of Nanjing University, Nanjing, Jiangsu province, China, 210029
| | - Michael J Forster
- 4. Department of Pharmacology and Neurosciences, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Liang-Jun Yan
- 1. Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
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Akhan G, Songu M, Ayik SO, Altay C, Kalemci S. Correlation between hippocampal sulcus width and severity of obstructive sleep apnea syndrome. Eur Arch Otorhinolaryngol 2014; 272:3763-8. [PMID: 25502740 DOI: 10.1007/s00405-014-3422-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 11/28/2014] [Indexed: 12/28/2022]
Abstract
The aim of the present study was to evaluate the relationship between obstructive sleep apnea syndrome (OSAS) severity and the hippocampal sulcus width in a cohort of subjects with OSAS and controls. A total of 149 OSAS patients and 60 nonapneic controls were included in the study. Overnight polysomnograpy was performed in all patients. Hippocampal sulcus width of the patients was measured by a radiologist blinded to the diagnosis of the patients. Other variables noted for each patient were as follows: gender, age, body mass index, apnea hypopnea index, Epworth sleepiness scale, sleep efficacy, mean saturation, lowest O2 saturation, longest apnea duration, neck circumference, waist circumference, hip circumference. A total of 149 OSAS patients were divided into three groups: mild OSAS (n = 54), moderate OSAS (n = 40), severe OSAS (n = 55) groups. The control group consisted of patients with AHI <5 (n = 60). Hippocampal sulcus width was 1.6 ± 0.83 mm in the control group; while 1.9 ± 0.81 mm in mild OSAS, 2.1 ± 0.60 mm in moderate OSAS, and 2.9 ± 0.58 mm in severe OSAS groups (p < 0.001). Correlation analysis of variables revealed that apnea hypopnea index (rs = 0.483, p < 0.001) was positively correlated with hippocampal sulcus width. Our findings demonstrated that severity of OSAS might be associated with various pathologic mechanisms including increased hippocampal sulcus width.
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Affiliation(s)
- Galip Akhan
- Faculty of Medicine, Department of Neurology, Izmir Katip Celebi University, Izmir, Turkey
| | - Murat Songu
- Department of Otorhinolaryngology, Ataturk Training and Research Hospital, Izmir Katip Celebi University, Izmir, Turkey.
| | - Sibel Oktem Ayik
- Faculty of Medicine, Department of Chest Diseases, Izmir Katip Celebi University, Izmir, Turkey
| | - Canan Altay
- Faculty of Medicine, Department of Radiology, Dokuz Eylul University, Izmir, Turkey
| | - Serdar Kalemci
- Faculty of Medicine, Department of Chest Diseases, Mugla University, Mugla, Turkey
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Shen Z, Jiang L, Yuan Y, Deng T, Zheng YR, Zhao YY, Li WL, Wu JY, Gao JQ, Hu WW, Zhang XN, Chen Z. Inhibition of G protein-coupled receptor 81 (GPR81) protects against ischemic brain injury. CNS Neurosci Ther 2014; 21:271-9. [PMID: 25495836 DOI: 10.1111/cns.12362] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 10/24/2014] [Accepted: 10/26/2014] [Indexed: 01/08/2023] Open
Abstract
AIM Lactates accumulate in ischemic brains. G protein-coupled receptor 81 (GPR81) is an endogenous receptor for lactate. We aimed to explore whether lactate is involved in ischemic injury via activating GPR81. METHODS N2A cells were transfected with GFP-GPR81 plasmids 24 h previously, and then treated with GPR81 antagonist 3-hydroxy-butyrate (3-OBA) alone or cotreated with agonists lactate or 3, 5-dihydroxybenzoic acid (3, 5-DHBA) during 3 h of oxygen-glucose deprivation (OGD). Adult male C57BL/6J mice and primary cultured cortical neurons were treated with 3-OBA at the onset of middle cerebral artery occlusion (MCAO) or OGD, respectively. RESULTS The GPR81 overexpression increased the cell vulnerability to ischemic injury. And GPR81 antagonism by 3-OBA significantly prevented cell death and brain injury after OGD and MCAO, respectively. Furthermore, inhibition of GPR81 reversed ischemia-induced apoptosis and extracellular signal-regulated kinase (ERK) signaling may be involved in the neuroprotection. CONCLUSIONS G protein-coupled receptor 81 (GPR81) inhibition attenuated ischemic neuronal death. Lactate may aggravate ischemic brain injury by activating GPR81. GPR81 antagonism might be a novel therapeutic strategy for the treatment of cerebral ischemia.
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Affiliation(s)
- Zhe Shen
- Department of Pharmacology, Key Laboratory of Medical Neurobiology of The Ministry of Health of China, Zhejiang Province Key Laboratory of Neurobiology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
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Endoplasmic reticulum stress plays critical role in brain damage after chronic intermittent hypoxia in growing rats. Exp Neurol 2014; 257:148-56. [PMID: 24810321 DOI: 10.1016/j.expneurol.2014.04.029] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 04/17/2014] [Accepted: 04/28/2014] [Indexed: 01/08/2023]
Abstract
Obstructive sleep apnea hypopnea syndrome (OSAHS) in children is associated with multiple system morbidities. Cognitive dysfunction as a result of central nervous system complication has been reported in children with OSAHS. However, the underlying mechanisms are poorly understood. Endoplasmic reticulum stress (ERS)-related apoptosis plays an important role in various diseases of the central nervous system, but very little is known about the role of ERS in mediating pathophysiological reactions to cognitive dysfunction in OSAHS. Chronic intermittent hypoxia (CIH) exposures, modeling OSAHS, across 2 and 4weeks in growing rats made more reference memory errors, working memory errors and total memory errors in the 8-Arm radial maze task, increased significantly TUNEL positive cells, upregulated the unfolded protein response in the hippocampus and prefrontal cortex as evidenced by increased phosphorylation of PKR-like endoplasmic reticulum kinase, inositol-requiring enzyme l and some downstream products. A selective inhibitor of eukaryotic initiation factor-2a dephosphorylation, salubrinal, prevented C/EBP-homologous protein activation in the hippocampus and prefrontal cortex throughout hypoxia/reoxygenation exposure. Our findings suggest that ERS mediated cell apoptosis may be one of the underlying mechanisms of cognitive dysfunction in OSAHS children. Further, a specific ERS inhibitor Salubrinal should be tested for neuroprotection against CIH-induced injury.
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Nguyen AQ, Cherry BH, Scott GF, Ryou MG, Mallet RT. Erythropoietin: powerful protection of ischemic and post-ischemic brain. Exp Biol Med (Maywood) 2014; 239:1461-75. [PMID: 24595981 DOI: 10.1177/1535370214523703] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Ischemic brain injury inflicted by stroke and cardiac arrest ranks among the leading causes of death and long-term disability in the United States. The brain consumes large amounts of metabolic substrates and oxygen to sustain its energy requirements. Consequently, the brain is exquisitely sensitive to interruptions in its blood supply, and suffers irreversible damage after 10-15 min of severe ischemia. Effective treatments to protect the brain from stroke and cardiac arrest have proven elusive, due to the complexities of the injury cascades ignited by ischemia and reperfusion. Although recombinant tissue plasminogen activator and therapeutic hypothermia have proven efficacious for stroke and cardiac arrest, respectively, these treatments are constrained by narrow therapeutic windows, potentially detrimental side-effects and the limited availability of hypothermia equipment. Mounting evidence demonstrates the cytokine hormone erythropoietin (EPO) to be a powerful neuroprotective agent and a potential adjuvant to established therapies. Classically, EPO originating primarily in the kidneys promotes erythrocyte production by suppressing apoptosis of proerythroid progenitors in bone marrow. However, the brain is capable of producing EPO, and EPO's membrane receptors and signaling components also are expressed in neurons and astrocytes. EPO activates signaling cascades that increase the brain's resistance to ischemia-reperfusion stress by stabilizing mitochondrial membranes, limiting formation of reactive oxygen and nitrogen intermediates, and suppressing pro-inflammatory cytokine production and neutrophil infiltration. Collectively, these mechanisms preserve functional brain tissue and, thus, improve neurocognitive recovery from brain ischemia. This article reviews the mechanisms mediating EPO-induced brain protection, critiques the clinical utility of exogenous EPO to preserve brain threatened by ischemic stroke and cardiac arrest, and discusses the prospects for induction of EPO production within the brain by the intermediary metabolite, pyruvate.
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Affiliation(s)
- Anh Q Nguyen
- Department of Integrative Physiology and Cardiovascular Research Institute, University of North Texas Health Science Center, Fort Worth, TX 76107-2699
| | - Brandon H Cherry
- Department of Integrative Physiology and Cardiovascular Research Institute, University of North Texas Health Science Center, Fort Worth, TX 76107-2699
| | - Gary F Scott
- Department of Integrative Physiology and Cardiovascular Research Institute, University of North Texas Health Science Center, Fort Worth, TX 76107-2699
| | - Myoung-Gwi Ryou
- Department of Integrative Physiology and Cardiovascular Research Institute, University of North Texas Health Science Center, Fort Worth, TX 76107-2699
| | - Robert T Mallet
- Department of Integrative Physiology and Cardiovascular Research Institute, University of North Texas Health Science Center, Fort Worth, TX 76107-2699
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Lim DC, Pack AI. Obstructive sleep apnea and cognitive impairment: addressing the blood-brain barrier. Sleep Med Rev 2014; 18:35-48. [PMID: 23541562 PMCID: PMC3758447 DOI: 10.1016/j.smrv.2012.12.003] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Revised: 12/21/2012] [Accepted: 12/24/2012] [Indexed: 12/14/2022]
Abstract
Increasing data support a connection between obstructive sleep apnea (OSA) and cognitive impairment but a causal link has yet to be established. Although neuronal loss has been linked to cognitive impairment, emerging theories propose that changes in synaptic plasticity can cause cognitive impairment. Studies demonstrate that disruption to the blood-brain barrier (BBB), which is uniquely structured to tightly maintain homeostasis inside the brain, leads to changes in the brain's microenvironment and affects synaptic plasticity. Cyclical intermittent hypoxia is a stressor that could disrupt the BBB via molecular responses already known to occur in either OSA patients or animal models of intermittent hypoxia. However, we do not yet know if or how intermittent hypoxia can cause cognitive impairment by mechanisms operating at the BBB. Therefore, we propose that initially, adaptive homeostatic responses at the BBB occur in response to increased oxygen and nutrient demand, specifically through regulation of influx and efflux BBB transporters that alter microvessel permeability. We further hypothesize that although these responses are initially adaptive, these changes in BBB transporters can have long-term consequences that disrupt the brain's microenvironment and alter synaptic plasticity leading to cognitive impairment.
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Affiliation(s)
- Diane C Lim
- Department of Medicine, Division of Sleep Medicine, and Center for Sleep and Circadian Neurobiology, University of Pennsylvania, 125 South 31st Street, Suite 2100, Philadelphia, PA 19104, USA.
| | - Allan I Pack
- Department of Medicine, Division of Sleep Medicine, and Center for Sleep and Circadian Neurobiology, University of Pennsylvania, 125 South 31st Street, Suite 2100, Philadelphia, PA 19104, USA.
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Vijay N, Morris ME. Role of monocarboxylate transporters in drug delivery to the brain. Curr Pharm Des 2013; 20:1487-98. [PMID: 23789956 DOI: 10.2174/13816128113199990462] [Citation(s) in RCA: 248] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 06/18/2013] [Indexed: 02/08/2023]
Abstract
Monocarboxylate transporters (MCTs) are known to mediate the transport of short chain monocarboxylates such as lactate, pyruvate and butyrate. Currently, fourteen members of this transporter family have been identified by sequence homology, of which only the first four members (MCT1- MCT4) have been shown to mediate the proton-linked transport of monocarboxylates. Another transporter family involved in the transport of endogenous monocarboxylates is the sodium coupled MCTs (SMCTs). These act as a symporter and are dependent on a sodium gradient for their functional activity. MCT1 is the predominant transporter among the MCT isoforms and is present in almost all tissues including kidney, intestine, liver, heart, skeletal muscle and brain. The various isoforms differ in terms of their substrate specificity and tissue localization. Due to the expression of these transporters in the kidney, intestine, and brain, they may play an important role in influencing drug disposition. Apart from endogenous short chain monocarboxylates, they also mediate the transport of exogenous drugs such as salicylic acid, valproic acid, and simvastatin acid. The influence of MCTs on drug pharmacokinetics has been extensively studied for γ-hydroxybutyrate (GHB) including distribution of this drug of abuse into the brain and the results will be summarized in this review. The physiological role of these transporters in the brain and their specific cellular localization within the brain will also be discussed. This review will also focus on utilization of MCTs as potential targets for drug delivery into the brain including their role in the treatment of malignant brain tumors.
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