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Mao Y, Zhuang Z, Chen Y, Zhang X, Shen Y, Lin G, Wu R. Imaging of glutamate in acute traumatic brain injury using chemical exchange saturation transfer. Quant Imaging Med Surg 2019; 9:1652-1663. [PMID: 31728309 DOI: 10.21037/qims.2019.09.08] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Background Chemical exchange saturation transfer (CEST) is an important contrast mechanism in the field of magnetic resonance imaging. Herein, we used CEST for glutamate (GluCEST) imaging to evaluate the Glu alterations in acute mild to moderate traumatic brain injury (TBI) and correlated such alterations with the cognitive outcome at 1-month postinjury. Methods Thirty-two patients with well-documented mild-to-moderate TBI and 15 healthy controls (HC group) underwent 3.0-Tesla magnetic resonance imaging (MRI) with GluCEST, and magnetic resonance spectroscopy (MRS) scans. The Montreal Cognitive Assessment (MoCA) examination was administered to all study subjects at 1-month postinjury for cognitive outcome acquisition and divided TBI patients into patients with good cognitive outcome (GCO group) and with poor cognitive outcome (PCO group). Results The GluCEST% values for the occipital gray matter (OGM) and bilateral parietooccipital white matter (PWM) were higher in the PCO group compared with the HC and GCO groups (P<0.05), whereas the GluCEST% value showed no significant differences between the GCO and HC groups (P>0.05). In comparison with HCs, TBI patients had a significantly increased GluCEST% value for the OGM and bilateral PWM (P<0.05). GluCEST performed better than MRS in the prediction of cognitive outcome for TBI patients (P<0.05). Conclusions Glu is significantly increased in acute TBI and strongly correlates with the cognitive outcome at 1month postinjury. GluCEST may supply new insight into TBI and help to improve the accuracy of short-term outcome prediction.
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Affiliation(s)
- Yifei Mao
- Department of Medical Imaging, The Second Affiliated Hospital, Medical College of Shantou University, Shantou 515041, China.,Department of Radiology, Shenzhen Maternity and Child Healthcare Hospital, Shenzhen 518028, China
| | - Zerui Zhuang
- Department of Neurosurgery, The Second Affiliated Hospital, Medical College of Shantou University, Shantou 515041, China
| | - Yanzi Chen
- Department of Medical Imaging, The Second Affiliated Hospital, Medical College of Shantou University, Shantou 515041, China
| | - Xiaolei Zhang
- Department of Neurosurgery, The Second Affiliated Hospital, Medical College of Shantou University, Shantou 515041, China
| | - Yuanyu Shen
- Department of Medical Imaging, The Second Affiliated Hospital, Medical College of Shantou University, Shantou 515041, China
| | - Guisen Lin
- Department of Medical Imaging, The Second Affiliated Hospital, Medical College of Shantou University, Shantou 515041, China
| | - Renhua Wu
- Department of Medical Imaging, The Second Affiliated Hospital, Medical College of Shantou University, Shantou 515041, China
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Zeiler FA, Thelin EP, Helmy A, Czosnyka M, Hutchinson PJA, Menon DK. A systematic review of cerebral microdialysis and outcomes in TBI: relationships to patient functional outcome, neurophysiologic measures, and tissue outcome. Acta Neurochir (Wien) 2017; 159:2245-2273. [PMID: 28988334 PMCID: PMC5686263 DOI: 10.1007/s00701-017-3338-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 09/19/2017] [Indexed: 12/22/2022]
Abstract
OBJECTIVE To perform a systematic review on commonly measured cerebral microdialysis (CMD) analytes and their association to: (A) patient functional outcome, (B) neurophysiologic measures, and (C) tissue outcome; after moderate/severe TBI. The aim was to provide a foundation for next-generation CMD studies and build on existing pragmatic expert guidelines for CMD. METHODS We searched MEDLINE, BIOSIS, EMBASE, Global Health, Scopus, Cochrane Library (inception to October 2016). Strength of evidence was adjudicated using GRADE. RESULTS (A) Functional Outcome: 55 articles were included, assessing outcome as mortality or Glasgow Outcome Scale (GOS) at 3-6 months post-injury. Overall, there is GRADE C evidence to support an association between CMD glucose, glutamate, glycerol, lactate, and LPR to patient outcome at 3-6 months. (B) Neurophysiologic Measures: 59 articles were included. Overall, there currently exists GRADE C level of evidence supporting an association between elevated CMD measured mean LPR, glutamate and glycerol with elevated ICP and/or decreased CPP. In addition, there currently exists GRADE C evidence to support an association between elevated mean lactate:pyruvate ratio (LPR) and low PbtO2. Remaining CMD measures and physiologic outcomes displayed GRADE D or no evidence to support a relationship. (C) Tissue Outcome: four studies were included. Given the conflicting literature, the only conclusion that can be drawn is acute/subacute phase elevation of CMD measured LPR is associated with frontal lobe atrophy at 6 months. CONCLUSIONS This systematic review replicates previously documented relationships between CMD and various outcome, which have driven clinical application of the technique. Evidence assessments do not address the application of CMD for exploring pathophysiology or titrating therapy in individual patients, and do not account for the modulatory effect of therapy on outcome, triggered at different CMD thresholds in individual centers. Our findings support clinical application of CMD and refinement of existing guidelines.
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Affiliation(s)
- Frederick A. Zeiler
- Section of Neurosurgery, Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3A 1R9 Canada
- Clinician Investigator Program, University of Manitoba, Winnipeg, Canada
- Department of Anesthesia, Addenbrooke’s Hospital, University of Cambridge, Cambridge, UK
| | - Eric Peter Thelin
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0QQ UK
- Department of Clinical Neuroscience, Neurosurgical Research Laboratory, Karolinska University Hospital, Building R2:02, Karolinska Institutet, S-17176 Stockholm, Sweden
| | - Adel Helmy
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0QQ UK
| | - Marek Czosnyka
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0QQ UK
- Section of Brain Physics, Division of Neurosurgery, University of Cambridge, Cambridge, CB2 0QQ UK
| | - Peter J. A. Hutchinson
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0QQ UK
| | - David K. Menon
- Department of Anesthesia, Addenbrooke’s Hospital, University of Cambridge, Cambridge, UK
- Neurosciences Critical Care Unit, Addenbrooke’s Hospital, Cambridge, UK
- Queens’ College, Cambridge, UK
- National Institute for Health Research, Southampton, UK
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Tolias CM, Bullock MR. Critical appraisal of neuroprotection trials in head injury: what have we learned? NeuroRx 2005; 1:71-9. [PMID: 15717008 PMCID: PMC534913 DOI: 10.1602/neurorx.1.1.71] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
To date, despite very encouraging preclinical results, almost all phase II/III clinical neuroprotection trials in traumatic brain injury (TBI) have failed to show any consistent improvement in outcome for TBI patients. To understand the reasons behind such developments we need to review and evaluate the evolution of trial design as a result of our changing understanding of the pathophysiology of brain cell death and progress of translational research from the laboratory bench to the bedside. This paper attempts to critically appraise these neuroprotection trials, rationalize the paucity of effectiveness, review any recent developments in the field, and try to draw some conclusions on how to move forward.
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Affiliation(s)
- Christos M Tolias
- Division of Neurosurgery, Medical College of Virginia, Virginia Commonwealth University, Richmond, Virginia 23298-0631, USA
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Delorenzo RJ, Sun DA, Deshpande LS. Cellular mechanisms underlying acquired epilepsy: the calcium hypothesis of the induction and maintainance of epilepsy. Pharmacol Ther 2005; 105:229-66. [PMID: 15737406 PMCID: PMC2819430 DOI: 10.1016/j.pharmthera.2004.10.004] [Citation(s) in RCA: 202] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2004] [Accepted: 10/12/2004] [Indexed: 01/22/2023]
Abstract
Epilepsy is one of the most common neurological disorders. Although epilepsy can be idiopathic, it is estimated that up to 50% of all epilepsy cases are initiated by neurological insults and are called acquired epilepsy (AE). AE develops in 3 phases: (1) the injury (central nervous system [CNS] insult), (2) epileptogenesis (latency), and (3) the chronic epileptic (spontaneous recurrent seizure) phases. Status epilepticus (SE), stroke, and traumatic brain injury (TBI) are 3 major examples of common brain injuries that can lead to the development of AE. It is especially important to understand the molecular mechanisms that cause AE because it may lead to innovative strategies to prevent or cure this common condition. Recent studies have offered new insights into the cause of AE and indicate that injury-induced alterations in intracellular calcium concentration levels [Ca(2+)](i) and calcium homeostatic mechanisms play a role in the development and maintenance of AE. The injuries that cause AE are different, but they share a common molecular mechanism for producing brain damage-an increase in extracellular glutamate concentration that causes increased intracellular neuronal calcium, leading to neuronal injury and/or death. Neurons that survive the injury induced by glutamate and are exposed to increased [Ca(2+)](i) are the cellular substrates to develop epilepsy because dead cells do not seize. The neurons that survive injury sustain permanent long-term plasticity changes in [Ca(2+)](i) and calcium homeostatic mechanisms that are permanent and are a prominent feature of the epileptic phenotype. In the last several years, evidence has accumulated indicating that the prolonged alteration in neuronal calcium dynamics plays an important role in the induction and maintenance of the prolonged neuroplasticity changes underlying the epileptic phenotype. Understanding the role of calcium as a second messenger in the induction and maintenance of epilepsy may provide novel insights into therapeutic advances that will prevent and even cure AE.
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Affiliation(s)
- Robert J Delorenzo
- Department of Neurology, Virginia Commonwealth University, School of Medicine, Richmond, VA 23298-0599, USA.
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Benjamin RK, Hochberg FH, Fox E, Bungay PM, Elmquist WF, Stewart CF, Gallo JM, Collins JM, Pelletier RP, de Groot JF, Hickner RC, Cavus I, Grossman SA, Colvin OM. Review of microdialysis in brain tumors, from concept to application: first annual Carolyn Frye-Halloran symposium. Neuro Oncol 2004; 6:65-74. [PMID: 14769143 PMCID: PMC1871970 DOI: 10.1215/s1152851703000103] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
In individuals with brain tumors, pharmacodynamic and pharmacokinetic studies of therapeutic agents have historically used analyses of drug concentrations in serum or cerebrospinal fluid, which unfortunately do not necessarily reflect concentrations within the tumor and adjacent brain. This review article introduces to neurological and medical oncologists, as well as pharmacologists, the application of microdialysis in monitoring drug metabolism and delivery within the fluid of the interstitial space of brain tumor and its surroundings. Microdialysis samples soluble molecules from the extracellular fluid via a semipermeable membrane at the tip of a probe. In the past decade, it has been used predominantly in neurointensive care in the setting of brain trauma, vasospasm, epilepsy,and intracerebral hemorrhage. At the first Carolyn Frye-Halloran Symposium held at Massachusetts General Hospital in March 2002, the concept of microdialysis was extended to specifically address its possible use in treating brain tumor patients. In doing so we provide a rationale for the use of this technology by a National Cancer Institute consortium, New Approaches to Brain Tumor Therapy, to measure levels of drugs in brain tissue as part of phase 1 trials.
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Affiliation(s)
- Ramsis K Benjamin
- Brain Tumor Center, Massachusetts General Hospital, Boston, MA 02114, USA.
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