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Witkin JM, Shafique H, Cerne R, Smith JL, Marini AM, Lipsky RH, Delery E. Mechanistic and therapeutic relationships of traumatic brain injury and γ-amino-butyric acid (GABA). Pharmacol Ther 2024; 256:108609. [PMID: 38369062 DOI: 10.1016/j.pharmthera.2024.108609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Revised: 01/18/2024] [Accepted: 02/01/2024] [Indexed: 02/20/2024]
Abstract
Traumatic brain injury (TBI) is a highly prevalent medical condition for which no medications specific for the prophylaxis or treatment of the condition as a whole exist. The spectrum of symptoms includes coma, headache, seizures, cognitive impairment, depression, and anxiety. Although it has been known for years that the inhibitory neurotransmitter γ-amino-butyric acid (GABA) is involved in TBI, no novel therapeutics based upon this mechanism have been introduced into clinical practice. We review the neuroanatomical, neurophysiological, neurochemical, and neuropharmacological relationships of GABA neurotransmission to TBI with a view toward new potential GABA-based medicines. The long-standing idea that excitatory and inhibitory (GABA and others) balances are disrupted by TBI is supported by the experimental data but has failed to invent novel methods of restoring this balance. The slow progress in advancing new treatments is due to the complexity of the disorder that encompasses multiple dynamically interacting biological processes including hemodynamic and metabolic systems, neurodegeneration and neurogenesis, major disruptions in neural networks and axons, frank brain lesions, and a multitude of symptoms that have differential neuronal and neurohormonal regulatory mechanisms. Although the current and ongoing clinical studies include GABAergic drugs, no novel GABA compounds are being explored. It is suggested that filling the gap in understanding the roles played by specific GABAA receptor configurations within specific neuronal circuits could help define new therapeutic approaches. Further research into the temporal and spatial delivery of GABA modulators should also be useful. Along with GABA modulation, research into the sequencing of GABA and non-GABA treatments will be needed.
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Affiliation(s)
- Jeffrey M Witkin
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent Hospital, Indianapolis, IN, USA; Departments of Neuroscience and Trauma Research, Ascension St. Vincent Hospital, Indianapolis, IN, USA; RespireRx Pharmaceuticals Inc, Glen Rock, NJ, USA.
| | | | - Rok Cerne
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent Hospital, Indianapolis, IN, USA; RespireRx Pharmaceuticals Inc, Glen Rock, NJ, USA; Department of Anatomy and Cell Biology, Indiana University/Purdue University, Indianapolis, IN, USA
| | - Jodi L Smith
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent Hospital, Indianapolis, IN, USA
| | - Ann M Marini
- Department of Neurology, Program in Neuroscience, and Molecular and Cellular Biology Program, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Robert H Lipsky
- Department of Neurology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Elizabeth Delery
- College of Osteopathic Medicine, Marian University, Indianapolis, IN, USA.
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Bylicky MA, Mueller GP, Day RM. Mechanisms of Endogenous Neuroprotective Effects of Astrocytes in Brain Injury. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:6501031. [PMID: 29805731 PMCID: PMC5901819 DOI: 10.1155/2018/6501031] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 02/19/2018] [Indexed: 12/11/2022]
Abstract
Astrocytes, once believed to serve only as "glue" for the structural support of neurons, have been demonstrated to serve critical functions for the maintenance and protection of neurons, especially under conditions of acute or chronic injury. There are at least seven distinct mechanisms by which astrocytes protect neurons from damage; these are (1) protection against glutamate toxicity, (2) protection against redox stress, (3) mediation of mitochondrial repair mechanisms, (4) protection against glucose-induced metabolic stress, (5) protection against iron toxicity, (6) modulation of the immune response in the brain, and (7) maintenance of tissue homeostasis in the presence of DNA damage. Astrocytes support these critical functions through specialized responses to stress or toxic conditions. The detoxifying activities of astrocytes are essential for maintenance of the microenvironment surrounding neurons and in whole tissue homeostasis. Improved understanding of the mechanisms by which astrocytes protect the brain could lead to the development of novel targets for the development of neuroprotective strategies.
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Affiliation(s)
- Michelle A. Bylicky
- Department of Anatomy, Physiology, and Genetics, The Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - Gregory P. Mueller
- Department of Anatomy, Physiology, and Genetics, The Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - Regina M. Day
- Department of Pharmacology and Molecular Therapeutics, The Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
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Nägeli M, Fasshauer M, Sommerfeld J, Fendel A, Brandi G, Stover JF. Prolonged continuous intravenous infusion of the dipeptide L-alanine- L-glutamine significantly increases plasma glutamine and alanine without elevating brain glutamate in patients with severe traumatic brain injury. Crit Care 2014; 18:R139. [PMID: 24992948 PMCID: PMC4227121 DOI: 10.1186/cc13962] [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: 06/24/2013] [Accepted: 06/02/2014] [Indexed: 01/21/2023] Open
Abstract
INTRODUCTION Low plasma glutamine levels are associated with worse clinical outcome. Intravenous glutamine infusion dose- dependently increases plasma glutamine levels, thereby correcting hypoglutaminemia. Glutamine may be transformed to glutamate which might limit its application at a higher dose in patients with severe traumatic brain injury (TBI). To date, the optimal glutamine dose required to normalize plasma glutamine levels without increasing plasma and cerebral glutamate has not yet been defined. METHODS Changes in plasma and cerebral glutamine, alanine, and glutamate as well as indirect signs of metabolic impairment reflected by increased intracranial pressure (ICP), lactate, lactate-to-pyruvate ratio, electroencephalogram (EEG) activity were determined before, during, and after continuous intravenous infusion of 0.75 g L-alanine-L-glutamine which was given either for 24 hours (group 1, n = 6) or 5 days (group 2, n = 6) in addition to regular enteral nutrition. Lab values including nitrogen balance, urea and ammonia were determined daily. RESULTS Continuous L-alanine-L-glutamine infusion significantly increased plasma and cerebral glutamine as well as alanine levels, being mostly sustained during the 5 day infusion phase (plasma glutamine: from 295 ± 62 to 500 ± 145 μmol/ l; brain glutamine: from 183 ± 188 to 549 ± 120 μmol/ l; plasma alanine: from 327 ± 91 to 622 ± 182 μmol/ l; brain alanine: from 48 ± 55 to 89 ± 129 μmol/ l; p < 0.05, ANOVA, post hoc Dunn's test). CONCLUSIONS High dose L-alanine-L-glutamine infusion (0.75 g/ kg/ d up to 5 days) increased plasma and brain glutamine and alanine levels. This was not associated with elevated glutamate or signs of potential glutamate-mediated cerebral injury. The increased nitrogen load should be considered in patients with renal and hepatic dysfunction. TRIAL REGISTRATION Clinicaltrials.gov NCT02130674. Registered 5 April 2014.
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Affiliation(s)
- Mirjam Nägeli
- Surgical Intensive Care Medicine, University Hospital Zuerich, Raemistrasse 100, Zuerich 8091, Switzerland
| | - Mario Fasshauer
- Surgical Intensive Care Medicine, University Hospital Zuerich, Raemistrasse 100, Zuerich 8091, Switzerland
| | - Jutta Sommerfeld
- Surgical Intensive Care Medicine, University Hospital Zuerich, Raemistrasse 100, Zuerich 8091, Switzerland
| | - Angela Fendel
- Surgical Intensive Care Medicine, University Hospital Zuerich, Raemistrasse 100, Zuerich 8091, Switzerland
| | - Giovanna Brandi
- Surgical Intensive Care Medicine, University Hospital Zuerich, Raemistrasse 100, Zuerich 8091, Switzerland
| | - John F Stover
- Surgical Intensive Care Medicine, University Hospital Zuerich, Raemistrasse 100, Zuerich 8091, Switzerland
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Vuille-Dit-Bille RN, Ha-Huy R, Stover JF. Changes in plasma phenylalanine, isoleucine, leucine, and valine are associated with significant changes in intracranial pressure and jugular venous oxygen saturation in patients with severe traumatic brain injury. Amino Acids 2011; 43:1287-96. [DOI: 10.1007/s00726-011-1202-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Accepted: 12/09/2011] [Indexed: 01/31/2023]
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Windmiller JR, Valdés-Ramírez G, Zhou N, Zhou M, Miller PR, Jin C, Brozik SM, Polsky R, Katz E, Narayan R, Wang J. Bicomponent Microneedle Array Biosensor for Minimally-Invasive Glutamate Monitoring. ELECTROANAL 2011. [DOI: 10.1002/elan.201100361] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Zhou N, Windmiller JR, Valdés-Ramírez G, Zhou M, Halámek J, Katz E, Wang J. Enzyme-based NAND gate for rapid electrochemical screening of traumatic brain injury in serum. Anal Chim Acta 2011; 703:94-100. [PMID: 21843680 DOI: 10.1016/j.aca.2011.07.023] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2011] [Revised: 07/05/2011] [Accepted: 07/12/2011] [Indexed: 11/26/2022]
Abstract
We report on the development of a rapid enzyme logic gate-based electrochemical assay for the assessment of traumatic brain injury (TBI). The concept harnesses a biocatalytic cascade that emulates the functionality of a Boolean NAND gate in order to process relevant physiological parameters in the biochemical domain. The enzymatic backbone ensures that a high-fidelity diagnosis of traumatic brain injury can be tendered in a rapid fashion when the concentrations of key serum-based biomarkers reach pathological levels. The excitatory neurotransmitter glutamate and the enzyme lactate dehydrogenase were used here as clinically-relevant input TBI biomarkers, in connection to the low-potential detection of the NADH product in the presence of methylene green at a glassy carbon electrode. A systematic optimization of the gate and the entire protocol has resulted in the effective discrimination between the physiological and pathological logic levels. Owing to its robust design, the enzyme-based logic gate mitigates potential interferences from both physiological and electroactive sources and is able to perform direct measurements in human serum samples. Granted further detailed clinical validation, this proof-of-concept study demonstrates the potential of the electrochemical assay to aid in the rapid and decentralized diagnosis of TBI.
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Affiliation(s)
- Nandi Zhou
- Department of NanoEngineering, University of California at San Diego, La Jolla, 92093-0448, USA
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Clauss R. Neurotransmitters in Coma, Vegetative and Minimally Conscious States, pharmacological interventions. Med Hypotheses 2010; 75:287-90. [DOI: 10.1016/j.mehy.2010.03.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Accepted: 03/06/2010] [Indexed: 12/25/2022]
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Effects of blood glutamate scavenging on cortical evoked potentials. Cell Mol Neurobiol 2010; 30:1101-6. [PMID: 20607387 DOI: 10.1007/s10571-010-9542-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Accepted: 06/23/2010] [Indexed: 10/19/2022]
Abstract
It is well known that traumatic or ischemic brain injury is followed by acute excitotoxicity caused by the presence of abnormally high glutamate (Glu) in brain fluids. It has recently been demonstrated that excess Glu can be eliminated from brain into blood following the intravenous administration of oxaloacetate (OxAc), which, by scavenging blood Glu, induces an enhanced and neuroprotective brain-to-blood Glu efflux. In this study, we subjected rats to intravenous OxAc administration (i.v., 12.5, 25, and 50 mg/kg, respectively), and studied its effects on somatosensory evoked cortical potentials (EPs). Against our expectation, the amplitudes of EPs did not decrease but increased in a dose- and time-dependent manner after OxAc administration. Similar effects were observed when blood Glu scavenging was enhanced by combining OxAc (12.5 mg/kgbw) with recombinant glutamate-oxaloacetate transaminase (GOT, 0.14 nmol/100 g rat). On the basis of these results, we suggest that the changes of amplitudes of the EPs involve not only a glutamatergic but also the weakening of a GABAergic component. We cannot rule out the possibility that OxAc penetrates into the brain and improves mitochondrial functions.
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Zanier ER, Lee SM, Vespa PM, Giza CC, Hovda DA. Increased hippocampal CA3 vulnerability to low-level kainic acid following lateral fluid percussion injury. J Neurotrauma 2003; 20:409-20. [PMID: 12803974 DOI: 10.1089/089771503765355496] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
This study was designed to determine whether a secondary increase in neuronal activity induced by a low dose of kainic acid (KA), a glutamate analogue, exacerbates the anatomical damage in hippocampal regions following a mild lateral fluid percussion (LFP) brain injury. KA (9 mg/kg) was injected intraperitoneally in LFP-injured rats (n = 16) 1 h post-trauma. The neuronal loss in the CA3, CA4, and hilar regions at 7 days was quantified by two-dimensional cell counts. Hippocampal activation 15 min following KA injection was assessed by measuring local glucose metabolic rates (lCMR(glc)). Following LFP + KA, the ipsilateral side exhibited a 62.7%, 75.7%, and 52.1% decrease in the number of CA3, CA4 and hilar neurons, respectively, compared to naive rats (n = 3). These CA3 and CA4 neuronal counts were also significantly decreased compared to LFP + saline (n = 5) and sham + KA (n = 9) groups. The median Racine Score, used to rate the severity of behavioral seizures, was 4 in LFP + KA and 2 in sham + KA groups (p < 0.015), suggesting a reduction in seizure threshold following injury. lCMRglc in CA3 following LFP + KA was 121.8 +/- 2.0 (mean +/- SE) ipsilaterally and 71.5 +/- 5.4 contralaterally (p < 0.0012). No changes were found in the BBB permeability as measured by [(14)C]aminoisobutyric acid in CA3, CA4, and hilar regions. We conclude that the presence of low-level KA 1 h after LFP dramatically increases the extent of hippocampal activation and induces a striking loss of ipsilateral CA3 and CA4 pyramidal neurons. Neuronal excitation during a time of cellular vulnerability may trigger or amplify the cycle of secondary damage in functionally impaired, but potentially viable, tissue.
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Affiliation(s)
- Elisa Roncati Zanier
- Brain Injury Research Center, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
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