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Lidington D, Wan H, Bolz SS. Cerebral Autoregulation in Subarachnoid Hemorrhage. Front Neurol 2021; 12:688362. [PMID: 34367053 PMCID: PMC8342764 DOI: 10.3389/fneur.2021.688362] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 06/25/2021] [Indexed: 12/28/2022] Open
Abstract
Subarachnoid hemorrhage (SAH) is a devastating stroke subtype with a high rate of mortality and morbidity. The poor clinical outcome can be attributed to the biphasic course of the disease: even if the patient survives the initial bleeding emergency, delayed cerebral ischemia (DCI) frequently follows within 2 weeks time and levies additional serious brain injury. Current therapeutic interventions do not specifically target the microvascular dysfunction underlying the ischemic event and as a consequence, provide only modest improvement in clinical outcome. SAH perturbs an extensive number of microvascular processes, including the “automated” control of cerebral perfusion, termed “cerebral autoregulation.” Recent evidence suggests that disrupted cerebral autoregulation is an important aspect of SAH-induced brain injury. This review presents the key clinical aspects of cerebral autoregulation and its disruption in SAH: it provides a mechanistic overview of cerebral autoregulation, describes current clinical methods for measuring autoregulation in SAH patients and reviews current and emerging therapeutic options for SAH patients. Recent advancements should fuel optimism that microvascular dysfunction and cerebral autoregulation can be rectified in SAH patients.
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Affiliation(s)
- Darcy Lidington
- Department of Physiology, University of Toronto, Toronto, ON, Canada.,Toronto Centre for Microvascular Medicine at the Ted Rogers Centre for Heart Research Translational Biology and Engineering Program, University of Toronto, Toronto, ON, Canada
| | - Hoyee Wan
- Department of Physiology, University of Toronto, Toronto, ON, Canada.,Toronto Centre for Microvascular Medicine at the Ted Rogers Centre for Heart Research Translational Biology and Engineering Program, University of Toronto, Toronto, ON, Canada
| | - Steffen-Sebastian Bolz
- Department of Physiology, University of Toronto, Toronto, ON, Canada.,Toronto Centre for Microvascular Medicine at the Ted Rogers Centre for Heart Research Translational Biology and Engineering Program, University of Toronto, Toronto, ON, Canada.,Heart & Stroke/Richard Lewar Centre of Excellence for Cardiovascular Research, University of Toronto, Toronto, ON, Canada
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202
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Stackhouse TL, Mishra A. Neurovascular Coupling in Development and Disease: Focus on Astrocytes. Front Cell Dev Biol 2021; 9:702832. [PMID: 34327206 PMCID: PMC8313501 DOI: 10.3389/fcell.2021.702832] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/09/2021] [Indexed: 12/14/2022] Open
Abstract
Neurovascular coupling is a crucial mechanism that matches the high energy demand of the brain with a supply of energy substrates from the blood. Signaling within the neurovascular unit is responsible for activity-dependent changes in cerebral blood flow. The strength and reliability of neurovascular coupling form the basis of non-invasive human neuroimaging techniques, including blood oxygen level dependent (BOLD) functional magnetic resonance imaging. Interestingly, BOLD signals are negative in infants, indicating a mismatch between metabolism and blood flow upon neural activation; this response is the opposite of that observed in healthy adults where activity evokes a large oversupply of blood flow. Negative neurovascular coupling has also been observed in rodents at early postnatal stages, further implying that this is a process that matures during development. This rationale is consistent with the morphological maturation of the neurovascular unit, which occurs over a similar time frame. While neurons differentiate before birth, astrocytes differentiate postnatally in rodents and the maturation of their complex morphology during the first few weeks of life links them with synapses and the vasculature. The vascular network is also incomplete in neonates and matures in parallel with astrocytes. Here, we review the timeline of the structural maturation of the neurovascular unit with special emphasis on astrocytes and the vascular tree and what it implies for functional maturation of neurovascular coupling. We also discuss similarities between immature astrocytes during development and reactive astrocytes in disease, which are relevant to neurovascular coupling. Finally, we close by pointing out current gaps in knowledge that must be addressed to fully elucidate the mechanisms underlying neurovascular coupling maturation, with the expectation that this may also clarify astrocyte-dependent mechanisms of cerebrovascular impairment in neurodegenerative conditions in which reduced or negative neurovascular coupling is noted, such as stroke and Alzheimer’s disease.
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Affiliation(s)
- Teresa L Stackhouse
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, United States
| | - Anusha Mishra
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, United States.,Knight Cardiovascular Institute, Oregon Health & Sciences University, Portland, OR, United States
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203
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Peinkhofer C, Martial C, Cassol H, Laureys S, Kondziella D. The evolutionary origin of near-death experiences: a systematic investigation. Brain Commun 2021; 3:fcab132. [PMID: 34240053 PMCID: PMC8260963 DOI: 10.1093/braincomms/fcab132] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/18/2021] [Accepted: 05/05/2021] [Indexed: 11/28/2022] Open
Abstract
Near-death experiences are known from all parts of the world, various times and
numerous cultural backgrounds. This universality suggests that near-death
experiences may have a biological origin and purpose. Adhering to a
preregistered protocol, we investigate the hypothesis that thanatosis, aka
death-feigning, a last-resort defense mechanism in animals, is the evolutionary
origin of near-death experiences. We first show that thanatosis is a highly
preserved survival strategy occurring at all major nodes in a cladogram ranging
from insects to humans. We then show that humans under attack by animal, human
and ‘modern’ predators can experience both thanatosis and
near-death experiences, and we further show that the phenomenology and the
effects of the two overlap. In summary, we build a line of evidence suggesting
that thanatosis is the evolutionary foundation of near-death experiences and
that their shared biological purpose is the benefit of survival. We propose that
the acquisition of language enabled humans to transform these events from
relatively stereotyped death-feigning under predatory attacks into the rich
perceptions that form near-death experiences and extend to non-predatory
situations.
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Affiliation(s)
- Costanza Peinkhofer
- Department of Neurology, Rigshospitalet, Copenhagen University Hospital, Copenhagen 2100, Denmark
| | - Charlotte Martial
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège 4000, Belgium
| | - Helena Cassol
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège 4000, Belgium
| | - Steven Laureys
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège 4000, Belgium
| | - Daniel Kondziella
- Department of Neurology, Rigshospitalet, Copenhagen University Hospital, Copenhagen 2100, Denmark
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204
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Oka F, Sadeghian H, Yaseen MA, Fu B, Kura S, Qin T, Sakadžić S, Sugimoto K, Inoue T, Ishihara H, Nomura S, Suzuki M, Ayata C. Intracranial pressure spikes trigger spreading depolarizations. Brain 2021; 145:194-207. [PMID: 34245240 PMCID: PMC9126007 DOI: 10.1093/brain/awab256] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 05/29/2021] [Accepted: 06/17/2021] [Indexed: 01/09/2023] Open
Abstract
Spreading depolarizations are highly prevalent and spatiotemporally punctuated events worsening the outcome of brain injury. Trigger factors are poorly understood but may be linked to sudden worsening in supply-demand mismatch in compromised tissue. Sustained or transient elevations in intracranial pressure are also prevalent in the injured brain. Here, using a mouse model of large hemispheric ischaemic stroke, we show that mild and brief intracranial pressure elevations (20 or 30 mmHg for just 3 min) potently trigger spreading depolarizations in ischaemic penumbra (4-fold increase in spreading depolarization occurrence). We also show that 30 mmHg intracranial pressure spikes as brief as 30 s are equally effective. In contrast, sustained intracranial pressure elevations to the same level for 30 min do not significantly increase the spreading depolarization rate, suggesting that an abrupt disturbance in the steady state equilibrium is required to trigger a spreading depolarization. Laser speckle flowmetry consistently showed a reduction in tissue perfusion, and two-photon pO2 microscopy revealed a drop in venous pO2 during the intracranial pressure spikes suggesting increased oxygen extraction fraction, and therefore, worsening supply-demand mismatch. These haemodynamic changes during intracranial pressure spikes were associated with highly reproducible increases in extracellular potassium levels in penumbra. Consistent with the experimental data, a higher rate of intracranial pressure spikes was associated with spreading depolarization clusters in a retrospective series of patients with aneurysmal subarachnoid haemorrhage with strong temporal correspondence. Altogether, our data show that intracranial pressure spikes, even when mild and brief, are capable of triggering spreading depolarizations. Aggressive prevention of intracranial pressure spikes may help reduce spreading depolarization occurrence and improve outcomes after brain injury.
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Affiliation(s)
- Fumiaki Oka
- Neurovascular Research Laboratory, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA,Department of Neurosurgery, Yamaguchi Graduate School of Medicine, Ube, Yamaguchi, 755-8505, Japan,Correspondence to: Fumiaki Oka, MD, PhD Department of Neurosurgery, Yamaguchi Graduate School of Medicine 1-1-1, Minami-Kogushi, Ube, Yamaguchi, 755-8505, Japan E-mail:
| | - Homa Sadeghian
- Neurovascular Research Laboratory, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
| | - Mohammad A Yaseen
- Optics Division, MGH/MIT/HMS Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
| | - Buyin Fu
- Optics Division, MGH/MIT/HMS Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
| | - Sreekanth Kura
- Optics Division, MGH/MIT/HMS Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
| | - Tao Qin
- Neurovascular Research Laboratory, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
| | - Sava Sakadžić
- Optics Division, MGH/MIT/HMS Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
| | - Kazutaka Sugimoto
- Department of Neurosurgery, Yamaguchi Graduate School of Medicine, Ube, Yamaguchi, 755-8505, Japan
| | - Takao Inoue
- Department of Advanced ThermoNeuroBiology, Yamaguchi Graduate School of Medicine, Ube, Yamaguchi, 755-8505, Japan
| | - Hideyuki Ishihara
- Department of Neurosurgery, Yamaguchi Graduate School of Medicine, Ube, Yamaguchi, 755-8505, Japan
| | - Sadahiro Nomura
- Department of Neurosurgery, Yamaguchi Graduate School of Medicine, Ube, Yamaguchi, 755-8505, Japan
| | - Michiyasu Suzuki
- Department of Advanced ThermoNeuroBiology, Yamaguchi Graduate School of Medicine, Ube, Yamaguchi, 755-8505, Japan
| | - Cenk Ayata
- Neurovascular Research Laboratory, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA,Stroke Service, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA,Correspondence may also be addressed to: Cenk Ayata, MD, PhD Massachusetts General Hospital, 149 13th street, Room 6408, Charlestown, MA 02129, USA E-mail:
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205
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Yu Z, Li W, Lan J, Hayakawa K, Ji X, Lo EH, Wang X. EphrinB2-EphB2 signaling for dendrite protection after neuronal ischemia in vivo and oxygen-glucose deprivation in vitro. J Cereb Blood Flow Metab 2021; 41:1744-1755. [PMID: 33325764 PMCID: PMC8221775 DOI: 10.1177/0271678x20973119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
In order to rescue neuronal function, neuroprotection should be required not only for the neuron soma but also the dendrites. Here, we propose the hypothesis that ephrin-B2-EphB2 signaling may be involved in dendritic degeneration after ischemic injury. A mouse model of focal cerebral ischemia with middle cerebral artery occlusion (MCAO) method was used for EphB2 signaling test in vivo. Primary cortical neuron culture and oxygen-glucose deprivation were used to assess EphB2 signaling in vitro. siRNA and soluble ephrin-B2 ectodomain were used to block ephrin-B2-Ephb2 signaling. In the mouse model of focal cerebral ischemia and in neurons subjected to oxygen-glucose deprivation, clustering of ephrin-B2 with its receptor EphB2 was detected. Phosphorylation of EphB2 suggested activation of this signaling pathway. RNA silencing of EphB2 prevented neuronal death and preserved dendritic length. To assess therapeutic potential, we compared the soluble EphB2 ectodomain with the NMDA antagonist MK801 in neurons after oxygen-glucose deprivation. Both agents equally reduced lactate dehydrogenase release as a general marker of neurotoxicity. However, only soluble EphB2 ectodomain protected the dendrites. These findings provide a proof of concept that ephrin-B2-EphB2 signaling may represent a novel therapeutic target to protect both the neuron soma as well as dendrites against ischemic injury.
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Affiliation(s)
- Zhanyang Yu
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Wenlu Li
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Jing Lan
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China.,Cerebrovascular Research Institute, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Kazuhide Hayakawa
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Xunming Ji
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China.,Cerebrovascular Research Institute, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Eng H Lo
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Xiaoying Wang
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA.,Clinical Neuroscience Research Center, Department of Neurosurgery, Tulane University School of Medicine, New Orleans, LA, USA
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206
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Szabó Í, Varga VÉ, Dvorácskó S, Farkas AE, Körmöczi T, Berkecz R, Kecskés S, Menyhárt Á, Frank R, Hantosi D, Cozzi NV, Frecska E, Tömböly C, Krizbai IA, Bari F, Farkas E. N,N-Dimethyltryptamine attenuates spreading depolarization and restrains neurodegeneration by sigma-1 receptor activation in the ischemic rat brain. Neuropharmacology 2021; 192:108612. [PMID: 34023338 DOI: 10.1016/j.neuropharm.2021.108612] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 04/23/2021] [Accepted: 05/13/2021] [Indexed: 12/19/2022]
Abstract
Dimethyltryptamine (DMT), an endogenous ligand of sigma-1 receptors (Sig-1Rs), acts against systemic hypoxia, but whether DMT may prevent cerebral ischemic injury is unexplored. Here global forebrain ischemia was created in anesthetized rats and aggravated with the induction of spreading depolarizations (SDs) and subsequent short hypoxia before reperfusion. Drugs (DMT, the selective Sig-1R agonist PRE-084, the Sig-1R antagonist NE-100, or the serotonin receptor antagonist asenapine) were administered intravenously alone or in combination while physiological variables and local field potential from the cerebral cortex was recorded. Neuroprotection and the cellular localization of Sig-1R were evaluated with immunocytochemistry. Plasma and brain DMT content was measured by 2D-LC-HRMS/MS. The affinity of drugs for cerebral Sig-1R was evaluated with a radioligand binding assay. Both DMT and PRE-084 mitigated SDs, counteracted with NE-100. Further, DMT attenuated SD when co-administered with asenapine, compared to asenapine alone. DMT reduced the number of apoptotic and ferroptotic cells and supported astrocyte survival. The binding affinity of DMT to Sig-1R matched previously reported values. Sig-1Rs were associated with the perinuclear cytoplasm of neurons, astrocytes and microglia, and with glial processes. According to these data, DMT may be considered as adjuvant pharmacological therapy in the management of acute cerebral ischemia.
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Affiliation(s)
- Írisz Szabó
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged; Korányi Fasor 9, Szeged, 6720, Hungary.
| | - Viktória É Varga
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged; Korányi Fasor 9, Szeged, 6720, Hungary.
| | - Szabolcs Dvorácskó
- Laboratory of Chemical Biology, Institute of Biochemistry, Biological Research Centre, Temesvári Krt 62, Szeged, 6726, Hungary; Department of Medical Chemistry, Faculty of Medicine, University of Szeged, Dóm Tér 8, Szeged, 6720, Hungary.
| | - Attila E Farkas
- Neurovascular Unit Research Group, Molecular Neurobiology Research Unit, Institute of Biophysics, Biological Research Centre, Temesvári Krt 62, Szeged, 6726, Hungary.
| | - Tímea Körmöczi
- Department of Medical Chemistry, Faculty of Medicine, University of Szeged, Dóm Tér 8, Szeged, 6720, Hungary; Institute of Pharmaceutical Analysis, Faculty of Pharmacy, University of Szeged, Somogyi U 4, Szeged, 6720, Hungary.
| | - Róbert Berkecz
- Department of Medical Chemistry, Faculty of Medicine, University of Szeged, Dóm Tér 8, Szeged, 6720, Hungary; Institute of Pharmaceutical Analysis, Faculty of Pharmacy, University of Szeged, Somogyi U 4, Szeged, 6720, Hungary.
| | - Szilvia Kecskés
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged; Korányi Fasor 9, Szeged, 6720, Hungary.
| | - Ákos Menyhárt
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged; Korányi Fasor 9, Szeged, 6720, Hungary.
| | - Rita Frank
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged; Korányi Fasor 9, Szeged, 6720, Hungary.
| | - Dóra Hantosi
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged; Korányi Fasor 9, Szeged, 6720, Hungary.
| | - Nicholas V Cozzi
- Neuropharmacology Laboratory, University of Wisconsin School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA; Alexander Shulgin Research Institute, 1483 Shulgin Road, Lafayette, CA, 94549, USA.
| | - Ede Frecska
- Department of Psychiatry, Faculty of Medicine, University of Debrecen, Nagyerdei Krt 94, Debrecen, 4032, Hungary.
| | - Csaba Tömböly
- Laboratory of Chemical Biology, Institute of Biochemistry, Biological Research Centre, Temesvári Krt 62, Szeged, 6726, Hungary.
| | - István A Krizbai
- Neurovascular Unit Research Group, Molecular Neurobiology Research Unit, Institute of Biophysics, Biological Research Centre, Temesvári Krt 62, Szeged, 6726, Hungary; Institute of Life Sciences, UVVG, 94 Bulevardul Revoluției, Arad, 310025, Romania.
| | - Ferenc Bari
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged; Korányi Fasor 9, Szeged, 6720, Hungary.
| | - Eszter Farkas
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged; Korányi Fasor 9, Szeged, 6720, Hungary.
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207
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O’Hare L, Asher JM, Hibbard PB. Migraine Visual Aura and Cortical Spreading Depression-Linking Mathematical Models to Empirical Evidence. Vision (Basel) 2021; 5:30. [PMID: 34200625 PMCID: PMC8293461 DOI: 10.3390/vision5020030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/15/2021] [Accepted: 05/24/2021] [Indexed: 01/10/2023] Open
Abstract
This review describes the subjective experience of visual aura in migraine, outlines theoretical models of this phenomenon, and explores how these may be linked to neurochemical, electrophysiological, and psychophysical differences in sensory processing that have been reported in migraine with aura. Reaction-diffusion models have been used to model the hallucinations thought to arise from cortical spreading depolarisation and depression in migraine aura. One aim of this review is to make the underlying principles of these models accessible to a general readership. Cortical spreading depolarisation and depression in these models depends on the balance of the diffusion rate between excitation and inhibition and the occurrence of a large spike in activity to initiate spontaneous pattern formation. We review experimental evidence, including recordings of brain activity made during the aura and attack phase, self-reported triggers of migraine, and psychophysical studies of visual processing in migraine with aura, and how these might relate to mechanisms of excitability that make some people susceptible to aura. Increased cortical excitability, increased neural noise, and fluctuations in oscillatory activity across the migraine cycle are all factors that are likely to contribute to the occurrence of migraine aura. There remain many outstanding questions relating to the current limitations of both models and experimental evidence. Nevertheless, reaction-diffusion models, by providing an integrative theoretical framework, support the generation of testable experimental hypotheses to guide future research.
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Affiliation(s)
- Louise O’Hare
- Division of Psychology, Nottingham Trent University, Nottingham NG1 4FQ, UK
| | - Jordi M. Asher
- Department of Psychology, University of Essex, Colchester CO4 3SQ, UK; (J.M.A.); (P.B.H.)
| | - Paul B. Hibbard
- Department of Psychology, University of Essex, Colchester CO4 3SQ, UK; (J.M.A.); (P.B.H.)
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208
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Hofmann BB, Fischer I, Engel A, Jannusch K, Donaldson DM, Karadag C, van Lieshout JH, Beseoglu K, Muhammad S, Turowski B, Hänggi D, Kamp MA, Rubbert C. MTT Heterogeneity in Perfusion CT Imaging as a Predictor of Outcome after Aneurysmal SAH. AJNR Am J Neuroradiol 2021; 42:1387-1395. [PMID: 34083263 DOI: 10.3174/ajnr.a7169] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 03/09/2021] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Impairment of tissue oxygenation caused by inhomogeneous microscopic blood flow distribution, the so-called capillary transit time heterogeneity, is thought to contribute to delayed cerebral ischemia after aneurysmal SAH but has so far not been systematically evaluated in patients. We hypothesized that heterogeneity of the MTT, derived from CTP parameters, would give insight into the clinical course of patients with aneurysmal SAH and may identify patients at risk of poor outcome. MATERIALS AND METHODS We retrospectively analyzed the heterogeneity of the MTT using the coefficient of variation in CTP scans from 132 patients. A multivariable logistic regression model was used to model the dichotomized mRS outcome. Linear regression was used to eliminate variables with high linear dependence. T tests were used to compare the means of 2 groups. Furthermore, the time of the maximum coefficient of variation for MTT after bleeding was evaluated for correlation with the mRS after 6 months. RESULTS On average, each patient underwent 5.3 CTP scans during his or her stay. Patients with high coefficient of variation for MTT presented more often with higher modified Fisher (P = .011) and World Federation of Neurosurgical Societies grades (P = .014). A high coefficient of variation for MTT at days 3-21 after aneurysmal SAH correlated significantly with a worse mRS score after 6 months (P = .016). We found no correlation between the time of the maximum coefficient of variation for MTT after bleeding and the patients' outcomes after 6 months (P = .203). CONCLUSIONS Heterogeneity of MTT in CTP after aneurysmal SAH correlates with the patients' outcomes. Because the findings are in line with the pathophysiologic concept of the capillary transit time heterogeneity, future studies should seek to verify the coefficient of variation for MTT as a potential imaging biomarker for outcome.
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Affiliation(s)
- B B Hofmann
- From the Department of Neurosurgery (B.B.H., I.F., A.E., D.M.D., C.K., J.H.v.L., K.B., S.M., D.H., M.A.K.), Medical Faculty, University Düsseldorf, Düsseldorf, Germany
| | - I Fischer
- From the Department of Neurosurgery (B.B.H., I.F., A.E., D.M.D., C.K., J.H.v.L., K.B., S.M., D.H., M.A.K.), Medical Faculty, University Düsseldorf, Düsseldorf, Germany
| | - A Engel
- From the Department of Neurosurgery (B.B.H., I.F., A.E., D.M.D., C.K., J.H.v.L., K.B., S.M., D.H., M.A.K.), Medical Faculty, University Düsseldorf, Düsseldorf, Germany
| | - K Jannusch
- Department of Diagnostic and Interventional Radiology (K.J., B.T., C.R.), Medical Faculty, University Düsseldorf, Düsseldorf, Germany
| | - D M Donaldson
- From the Department of Neurosurgery (B.B.H., I.F., A.E., D.M.D., C.K., J.H.v.L., K.B., S.M., D.H., M.A.K.), Medical Faculty, University Düsseldorf, Düsseldorf, Germany
| | - C Karadag
- Medical Faculty (C.K.), University Düsseldorf, Düsseldorf, Germany
| | - J H van Lieshout
- From the Department of Neurosurgery (B.B.H., I.F., A.E., D.M.D., C.K., J.H.v.L., K.B., S.M., D.H., M.A.K.), Medical Faculty, University Düsseldorf, Düsseldorf, Germany
| | - K Beseoglu
- From the Department of Neurosurgery (B.B.H., I.F., A.E., D.M.D., C.K., J.H.v.L., K.B., S.M., D.H., M.A.K.), Medical Faculty, University Düsseldorf, Düsseldorf, Germany
| | - S Muhammad
- From the Department of Neurosurgery (B.B.H., I.F., A.E., D.M.D., C.K., J.H.v.L., K.B., S.M., D.H., M.A.K.), Medical Faculty, University Düsseldorf, Düsseldorf, Germany
| | - B Turowski
- Department of Diagnostic and Interventional Radiology (K.J., B.T., C.R.), Medical Faculty, University Düsseldorf, Düsseldorf, Germany
| | - D Hänggi
- From the Department of Neurosurgery (B.B.H., I.F., A.E., D.M.D., C.K., J.H.v.L., K.B., S.M., D.H., M.A.K.), Medical Faculty, University Düsseldorf, Düsseldorf, Germany
| | - M A Kamp
- From the Department of Neurosurgery (B.B.H., I.F., A.E., D.M.D., C.K., J.H.v.L., K.B., S.M., D.H., M.A.K.), Medical Faculty, University Düsseldorf, Düsseldorf, Germany
| | - C Rubbert
- Department of Diagnostic and Interventional Radiology (K.J., B.T., C.R.), Medical Faculty, University Düsseldorf, Düsseldorf, Germany
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209
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Abstract
Our brains consist of 80% water, which is continuously shifted between different compartments and cell types during physiological and pathophysiological processes. Disturbances in brain water homeostasis occur with pathologies such as brain oedema and hydrocephalus, in which fluid accumulation leads to elevated intracranial pressure. Targeted pharmacological treatments do not exist for these conditions owing to our incomplete understanding of the molecular mechanisms governing brain water transport. Historically, the transmembrane movement of brain water was assumed to occur as passive movement of water along the osmotic gradient, greatly accelerated by water channels termed aquaporins. Although aquaporins govern the majority of fluid handling in the kidney, they do not suffice to explain the overall brain water movement: either they are not present in the membranes across which water flows or they appear not to be required for the observed flow of water. Notably, brain fluid can be secreted against an osmotic gradient, suggesting that conventional osmotic water flow may not describe all transmembrane fluid transport in the brain. The cotransport of water is an unconventional molecular mechanism that is introduced in this Review as a missing link to bridge the gap in our understanding of cellular and barrier brain water transport.
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Affiliation(s)
- Nanna MacAulay
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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210
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Recober A. Pathophysiology of Migraine. ACTA ACUST UNITED AC 2021; 27:586-596. [PMID: 34048393 DOI: 10.1212/con.0000000000000983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE OF REVIEW This article summarizes the current understanding of the pathophysiology of migraine, including some controversial aspects of the underlying mechanisms of the disorder. RECENT FINDINGS Recent functional neuroimaging studies focusing on the nonpainful symptoms of migraine have identified key areas of the central nervous system implicated in the early phases of a migraine attack. Clinical studies of spontaneous and provoked migraine attacks, together with preclinical studies using translational animal models, have led to a better understanding of the disease and the development of disease-specific and targeted therapies. SUMMARY Our knowledge of the pathophysiology of migraine has advanced significantly in the past decades. Current evidence supports our understanding of migraine as a complex cyclical brain disorder that likely results from dysfunctional sensory processing and dysregulation of homeostatic mechanisms. This article reviews the underlying mechanisms of the clinical manifestations of each phase of the migraine cycle.
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van Putten MJ, Fahlke C, Kafitz KW, Hofmeijer J, Rose CR. Dysregulation of Astrocyte Ion Homeostasis and Its Relevance for Stroke-Induced Brain Damage. Int J Mol Sci 2021; 22:5679. [PMID: 34073593 PMCID: PMC8198632 DOI: 10.3390/ijms22115679] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/21/2021] [Accepted: 05/22/2021] [Indexed: 12/14/2022] Open
Abstract
Ischemic stroke is a leading cause of mortality and chronic disability. Either recovery or progression towards irreversible failure of neurons and astrocytes occurs within minutes to days, depending on remaining perfusion levels. Initial damage arises from energy depletion resulting in a failure to maintain homeostasis and ion gradients between extra- and intracellular spaces. Astrocytes play a key role in these processes and are thus central players in the dynamics towards recovery or progression of stroke-induced brain damage. Here, we present a synopsis of the pivotal functions of astrocytes at the tripartite synapse, which form the basis of physiological brain functioning. We summarize the evidence of astrocytic failure and its consequences under ischemic conditions. Special emphasis is put on the homeostasis and stroke-induced dysregulation of the major monovalent ions, namely Na+, K+, H+, and Cl-, and their involvement in maintenance of cellular volume and generation of cerebral edema.
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Affiliation(s)
- Michel J.A.M. van Putten
- Department of Clinical Neurophysiology, University of Twente, 7522 NB Enschede, The Netherlands; (M.J.A.M.v.P.); (J.H.)
| | - Christoph Fahlke
- Institut für Biologische Informationsprozesse, Molekular-und Zellphysiologie (IBI-1), Forschungszentrum Jülich, 52425 Jülich, Germany;
| | - Karl W. Kafitz
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany;
| | - Jeannette Hofmeijer
- Department of Clinical Neurophysiology, University of Twente, 7522 NB Enschede, The Netherlands; (M.J.A.M.v.P.); (J.H.)
| | - Christine R. Rose
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany;
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212
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Li J, Song G, Jin Q, Liu L, Yang L, Wang Y, Zhang X, Zhao Z. The α2δ-1/NMDA receptor complex is involved in brain injury after intracerebral hemorrhage in mice. Ann Clin Transl Neurol 2021; 8:1366-1375. [PMID: 34032393 PMCID: PMC8283164 DOI: 10.1002/acn3.51372] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 03/15/2021] [Accepted: 04/15/2021] [Indexed: 12/12/2022] Open
Abstract
Background Intracerebral hemorrhage (ICH), a common cerebrovascular disease, seriously threatens human health and has severe secondary injuries, while existing treatment methods have many limitations. α2δ‐1 is a subunit of voltage‐gated Ca2+ channels (VGCCs) and can act on glutamate receptor N‐methyl‐D‐aspartate receptors (NMDARs) to relieve neuropathic pain. Methods We first performed ICH modeling on WT mice and Cacna2d1 knockout (KO) mice. The expression levels of GluN1 and α2δ‐1 were measured by Western blot and q‐PCR, and the interaction between the two proteins was evaluated by co‐precipitation. The neuronal apoptosis was detected by the TUNEL assay, and the expression levels of inflammatory factors were assessed by ELISA. The nerve functions of mice were evaluated using behavioral experiments including corner turn test and forelimb use asymmetry. Cerebral hematoma was indicated by brain water content and lesion volume. Results ICH up‐regulated the expression levels of α2δ‐1 and GluN1. KO of Cacna2d1 significantly reduced the ICH‐induced apoptosis. The treatment of gabapentin on α2δ‐1 also significantly reduced the occurrence of apoptosis. KO of Cacna2d1 also reduced the ICH‐induced levels of inflammatory factors. Furthermore, neural functions were also significantly improved. Conclusion Cacna2d1 KO alleviates cerebral hematoma in ICH mice, exhibits a significant regulating effect on its secondary injuries such as neuronal apoptosis and inflammation, and restores the nerve functions of ICH mice. Loss of Cacna2d1 can provide useful therapeutic clues for ICH treatment.
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Affiliation(s)
- Jingchen Li
- Department of Neurosurgery, The Second Hospital of Hebei Medical University, No. 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, China
| | - Guoqiang Song
- Department of Neurosurgery, The Second Hospital of Hebei Medical University, No. 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, China
| | - Qianxu Jin
- Department of Neurosurgery, The Second Hospital of Hebei Medical University, No. 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, China
| | - Liqiang Liu
- Department of Neurosurgery, The Second Hospital of Hebei Medical University, No. 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, China
| | - Liang Yang
- Department of Neurosurgery, The Second Hospital of Hebei Medical University, No. 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, China
| | - Yuanyu Wang
- Department of Neurosurgery, The Second Hospital of Hebei Medical University, No. 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, China
| | - Xuesong Zhang
- Department of Neurosurgery, The Second Hospital of Hebei Medical University, No. 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, China
| | - Zongmao Zhao
- Department of Neurosurgery, The Second Hospital of Hebei Medical University, No. 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, China
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Chen J, Tang P, Fu X. Cilostazol administration for subarachnoid hemorrhage: A meta-analysis of randomized controlled trials. J Clin Neurosci 2021; 89:305-310. [PMID: 34119285 DOI: 10.1016/j.jocn.2021.04.044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 03/22/2021] [Accepted: 04/30/2021] [Indexed: 11/18/2022]
Abstract
INTRODUCTION The efficacy of cilostazol administration to treat subarachnoid hemorrhage remains controversial. We conduct a systematic review and meta-analysis to explore the influence of cilostazol administration on treatment efficacy for subarachnoid hemorrhage. METHODS We have searched PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases through July 2020 for randomized controlled trials (RCTs) assessing the effect of cilostazol administration in patients with subarachnoid hemorrhage. This meta-analysis is performed using the random-effect model. RESULTS Four RCTs involving 405 patients were included in the meta-analysis. Overall, compared with control group for subarachnoid hemorrhage, cilostazol intervention can significantly reduce symptomatic vasospasm (OR = 0.35; 95% CI = 0.21 to 0.60; P = 0.0001) and cerebral infarction (OR = 0.40; 95% CI = 0.22 to 0.73; P = 0.003), as well as improve no or mild angiographic vasospasm (OR = 2.01; 95% CI = 1.19 to 3.42; P = 0.01) and mRS score ≤ 2 (OR = 2.70; 95% CI = 1.09 to 6.71; P = 0.03), but revealed no obvious influence on severe angiographic vasospasm (OR = 0.53; 95% CI = 0.27 to 1.02; P = 0.06). There were no increase in adverse events (OR = 1.17; 95% CI = 0.54 to 2.52; P = 0.69), hemorrhagic events (OR = 0.62; 95% CI = 0.06 to 6.27; P = 0.69) and cardiac events (OR = 2.14; 95% CI = 0.44 to 10.27; P = 0.34) after the cilostazol intervention than control intervention. CONCLUSIONS Cilostazol treatment may be effective to treat subarachnoid hemorrhage in the terms of symptomatic vasospasm, cerebral infarction, no or mild angiographic vasospasm and mRS score ≤ 2.
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Affiliation(s)
- Jinlong Chen
- Department of Critical Care Medicine, Daye People's Hospital, China.
| | - Pingjin Tang
- Operating Room, Suizhou Hospital, Hubei University of Medicine, China.
| | - Xiaojuan Fu
- Chongqing Medical and Pharmaceutical College, China.
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Lourbopoulos A, Mourouzis I, Xinaris C, Zerva N, Filippakis K, Pavlopoulos A, Pantos C. Translational Block in Stroke: A Constructive and "Out-of-the-Box" Reappraisal. Front Neurosci 2021; 15:652403. [PMID: 34054413 PMCID: PMC8160233 DOI: 10.3389/fnins.2021.652403] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 04/06/2021] [Indexed: 12/13/2022] Open
Abstract
Why can we still not translate preclinical research to clinical treatments for acute strokes? Despite > 1000 successful preclinical studies, drugs, and concepts for acute stroke, only two have reached clinical translation. This is the translational block. Yet, we continue to routinely model strokes using almost the same concepts we have used for over 30 years. Methodological improvements and criteria from the last decade have shed some light but have not solved the problem. In this conceptual analysis, we review the current status and reappraise it by thinking "out-of-the-box" and over the edges. As such, we query why other scientific fields have also faced the same translational failures, to find common denominators. In parallel, we query how migraine, multiple sclerosis, and hypothermia in hypoxic encephalopathy have achieved significant translation successes. Should we view ischemic stroke as a "chronic, relapsing, vascular" disease, then secondary prevention strategies are also a successful translation. Finally, based on the lessons learned, we propose how stroke should be modeled, and how preclinical and clinical scientists, editors, grant reviewers, and industry should reconsider their routine way of conducting research. Translational success for stroke treatments may eventually require a bold change with solutions that are outside of the box.
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Affiliation(s)
- Athanasios Lourbopoulos
- Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
- Department of Neurointensive Care Unit, Schoen Klinik Bad Aibling, Bad Aibling, Germany
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig Maximilian University, Munich, Germany
| | - Iordanis Mourouzis
- Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Christodoulos Xinaris
- IRCCS – Istituto di Ricerche Farmacologiche ‘Mario Negri’, Centro Anna Maria Astori, Bergamo, Italy
- University of Nicosia Medical School, Nicosia, Cyprus
| | - Nefeli Zerva
- Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Konstantinos Filippakis
- Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Angelos Pavlopoulos
- Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Constantinos Pantos
- Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
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Cheng S, Mao X, Lin X, Wehn A, Hu S, Mamrak U, Khalin I, Wostrack M, Ringel F, Plesnila N, Terpolilli NA. Acid-Ion Sensing Channel 1a Deletion Reduces Chronic Brain Damage and Neurological Deficits after Experimental Traumatic Brain Injury. J Neurotrauma 2021; 38:1572-1584. [PMID: 33779289 DOI: 10.1089/neu.2020.7568] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Traumatic brain injury (TBI) causes long-lasting neurodegeneration and cognitive impairments; however, the underlying mechanisms of these processes are not fully understood. Acid-sensing ion channels 1a (ASIC1a) are voltage-gated Na+- and Ca2+-channels shown to be involved in neuronal cell death; however, their role for chronic post-traumatic brain damage is largely unknown. To address this issue, we used ASIC1a-deficient mice and investigated their outcome up to 6 months after TBI. ASIC1a-deficient mice and their wild-type (WT) littermates were subjected to controlled cortical impact (CCI) or sham surgery. Brain water content was analyzed 24 h and behavioral outcome up to 6 months after CCI. Lesion volume was assessed longitudinally by magnetic resonance imaging and 6 months after injury by histology. Brain water content was significantly reduced in ASIC1a-/- animals compared to WT controls. Over time, ASIC1a-/- mice showed significantly reduced lesion volume and reduced hippocampal damage. This translated into improved cognitive function and reduced depression-like behavior. Microglial activation was significantly reduced in ASIC1a-/- mice. In conclusion, ASIC1a deficiency resulted in reduced edema formation acutely after TBI and less brain damage, functional impairments, and neuroinflammation up to 6 months after injury. Hence, ASIC1a seems to be involved in chronic neurodegeneration after TBI.
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Affiliation(s)
- Shiqi Cheng
- Institute for Stroke and Dementia Research, Munich University Hospital, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Xiang Mao
- Institute for Stroke and Dementia Research, Munich University Hospital, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Xiangjiang Lin
- Institute for Stroke and Dementia Research, Munich University Hospital, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Antonia Wehn
- Institute for Stroke and Dementia Research, Munich University Hospital, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Senbin Hu
- Institute for Stroke and Dementia Research, Munich University Hospital, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Uta Mamrak
- Institute for Stroke and Dementia Research, Munich University Hospital, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Igor Khalin
- Institute for Stroke and Dementia Research, Munich University Hospital, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Maria Wostrack
- Department of Neurosurgery, Technical University Munich, Munich, Germany
| | - Florian Ringel
- Department of Neurosurgery, University Medical Center Mainz, Mainz, Germany
| | - Nikolaus Plesnila
- Institute for Stroke and Dementia Research, Munich University Hospital, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Nicole A Terpolilli
- Institute for Stroke and Dementia Research, Munich University Hospital, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.,Department of Neurosurgery, Munich University Hospital, Munich, Germany
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216
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Frank R, Bari F, Menyhárt Á, Farkas E. Comparative analysis of spreading depolarizations in brain slices exposed to osmotic or metabolic stress. BMC Neurosci 2021; 22:33. [PMID: 33941084 PMCID: PMC8094470 DOI: 10.1186/s12868-021-00637-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 04/20/2021] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Recurrent spreading depolarizations (SDs) occur in stroke and traumatic brain injury and are considered as a hallmark of injury progression. The complexity of conditions associated with SD in the living brain encouraged researchers to study SD in live brain slice preparations, yet methodological differences among laboratories complicate integrative data interpretation. Here we provide a comparative evaluation of SD evolution in live brain slices, in response to selected SD triggers and in various media, under otherwise standardized experimental conditions. METHODS Rat live coronal brain slices (350 μm) were prepared (n = 51). Hypo-osmotic medium (Na+ content reduced from 130 to 60 mM, HM) or oxygen-glucose deprivation (OGD) were applied to cause osmotic or ischemic challenge. Brain slices superfused with artificial cerebrospinal fluid (aCSF) served as control. SDs were evoked in the control condition with pressure injection of KCl or electric stimulation. Local field potential (LFP) was recorded via an intracortical glass capillary electrode, or intrinsic optical signal imaging was conducted at white light illumination to characterize SDs. TTC and hematoxylin-eosin staining were used to assess tissue damage. RESULTS Severe osmotic stress or OGD provoked a spontaneous SD. In contrast with SDs triggered in aCSF, these spontaneous depolarizations were characterized by incomplete repolarization and prolonged duration. Further, cortical SDs under HM or OGD propagated over the entire cortex and occassionally invaded the striatum, while SDs in aCSF covered a significantly smaller cortical area before coming to a halt, and never spread to the striatum. SDs in HM displayed the greatest amplitude and the most rapid propagation velocity. Finally, spontaneous SD in HM and especially under OGD was followed by tissue injury. CONCLUSIONS While the failure of Na+/K+ ATP-ase is thought to impair tissue recovery from OGD-related SD, the tissue swelling-related hyper excitability and the exhaustion of astrocyte buffering capacity are suggested to promote SD evolution under osmotic stress. In contrast with OGD, SD propagating under hypo-osmotic condition is not terminal, yet it is associated with irreversible tissue injury. Further investigation is required to understand the mechanistic similarities or differences between the evolution of SDs spontaneously occurring in HM and under OGD.
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Affiliation(s)
- Rita Frank
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged, Korányi fasor 9, 6720, Szeged, Hungary
| | - Ferenc Bari
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged, Korányi fasor 9, 6720, Szeged, Hungary
| | - Ákos Menyhárt
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged, Korányi fasor 9, 6720, Szeged, Hungary.
| | - Eszter Farkas
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged, Korányi fasor 9, 6720, Szeged, Hungary.
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Abstract
Aneurysmal subarachnoid hemorrhage is a neurologic emergency that requires immediate patient stabilization and prompt diagnosis and treatment. Early measures should focus on principles of advanced cardiovascular life support. The aneurysm should be evaluated and treated in a comprehensive stroke center by a multidisciplinary team capable of endovascular and, operative approaches. Once the aneurysm is secured, the patient is best managed by a dedicated neurocritical care service to prevent and manage complications, including a syndrome of delayed neurologic decline. The goal of such specialized care is to prevent secondary injury, reduce length of stay, and improve outcomes for survivors of the disease.
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Affiliation(s)
- David Y Chung
- Division of Neurocritical Care, Department of Neurology, Boston Medical Center, Boston, MA, USA; Division of Neurocritical Care, Department of Neurology, Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA; Neurovascular Research Unit, Department of Radiology, Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA.
| | - Mohamad Abdalkader
- Department of Neurology, Boston University School of Medicine, Boston Medical Center, Boston, MA, USA; Department of Neurosurgery, Boston University School of Medicine, Boston Medical Center, Boston, MA, USA; Department of Radiology, Boston University School of Medicine, Boston Medical Center, Boston, MA, USA
| | - Thanh N Nguyen
- Department of Neurology, Boston University School of Medicine, Boston Medical Center, Boston, MA, USA; Department of Neurosurgery, Boston University School of Medicine, Boston Medical Center, Boston, MA, USA; Department of Radiology, Boston University School of Medicine, Boston Medical Center, Boston, MA, USA
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218
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Al-Moujahed A, Tran EM, Azad A, Vail D, Ludwig CA, Pasricha MV, Rosenblatt TR, Callaway NF, Moshfeghi DM. Risk of Retinal Artery Occlusion in Patients with Migraine. Am J Ophthalmol 2021; 225:157-165. [PMID: 33359716 DOI: 10.1016/j.ajo.2020.11.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 10/29/2020] [Accepted: 11/04/2020] [Indexed: 01/03/2023]
Abstract
PURPOSE We sought to determine if migraine is associated with increased risk of retinal artery occlusion (RAO). DESIGN Retrospective cohort study. METHODS We reviewed a large insurance claims database for patients with migraine and matched control subjects without migraine between 2007 and 2016. Cox proportional hazard regression models were used to investigate the association between migraine and risk of all RAO, central RAO (CRAO), branch RAO (BRAO), and "other" RAO, which includes transient and partial RAO. Primary outcome measures included the incidence of all RAO, including CRAO, BRAO, and other RAO, after first migraine diagnosis. RESULT There were 418,965 patients with migraine who met the study criteria and were included in the analysis with the appropriate matched control subjects. Among the 418,965 patients with migraine, 1060 (0.25%) were subsequently diagnosed with RAO, whereas only 335 (0.08%) of the patients without migraine were diagnosed with RAO. The hazard ratio (HR) for incident all RAO in patients with migraine compared with those without migraine was 3.48 (95% confidence interval [CI] 3.07-3.94; P < .0001). This association was consistent across all types of RAO, including CRAO (HR 1.62 [95% CI 1.15-2.28]; P = .004), BRAO (HR 2.09 [95% CI 1.60-2.72]; P < .001), and other types of RAO (HR 4.61 [95% CI 3.94-5.38]; P < .001). Patients with migraine with aura had a higher risk for incident RAO compared with those with migraine without aura (HR 1.58 [95% CI 1.40-1.79]; P < .001). This association was consistent for BRAO (HR 1.43 [95% CI 1.04-1.97]; P < .03) and other types of RAO (HR 1.67 [95% CI 1.45-1.91]; P < .001) but was not statistically significant for CRAO (HR 1.18 [95% CI 0.75-1.87]; P = .475). Significant risk factors for this association included increased age, male sex, acute coronary syndrome, valvular disease, carotid disease, hyperlipidemia, hypertension, retinal vasculitis or inflammation, and systemic lupus erythematosus. CONCLUSIONS Migraine is associated with increased risk of all types of RAO and migraine with aura is associated with increased risk of RAO compared with migraine without aura.
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219
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Amoo M, Henry J, Pender N, Brennan P, Campbell M, Javadpour M. Blood-brain barrier permeability imaging as a predictor for delayed cerebral ischaemia following subarachnoid haemorrhage. A narrative review. Acta Neurochir (Wien) 2021; 163:1457-1467. [PMID: 33404877 DOI: 10.1007/s00701-020-04670-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 12/01/2020] [Indexed: 01/17/2023]
Abstract
BACKGROUND Aneurysmal subarachnoid haemorrhage is associated with significant morbidity and mortality due to the myriad of complications contributing to early brain injury and delayed cerebral ischaemia. There is increasing interest in the exploration of the association between blood-brain barrier integrity and risks of delayed cerebral ischaemia and poor outcomes. Despite recent advances in cerebral imaging, radiographic imaging of blood-brain barrier disruption, as a biomarker for outcome prediction, has not been adopted in clinical practice. METHODS We performed a narrative review by searching for articles describing molecular changes or radiological identification of changes in BBB permeability following subarachnoid haemorrhage (SAH) on MEDLINE. Preclinical studies were analysed if reported structural changes and clinical studies were included if they investigated for radiological markers of BBB disruption and its correlation with delayed cerebral ischaemia. RESULTS There is ample preclinical evidence to suggest that there are structural changes in BBB permeability following SAH. The available clinical literature has demonstrated correlations between permeability imaging and outcomes following aneurysmal subarachnoid haemorrhage (aSAH). CONCLUSION Radiological biomarkers offer a potential non-invasive prognostication tool and may also allow early identifications of patients who may be at risk of DCI.
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220
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Adrenergic inhibition facilitates normalization of extracellular potassium after cortical spreading depolarization. Sci Rep 2021; 11:8150. [PMID: 33854148 PMCID: PMC8047013 DOI: 10.1038/s41598-021-87609-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 03/31/2021] [Indexed: 01/31/2023] Open
Abstract
Cortical spreading depolarization (CSD) is a propagating wave of tissue depolarization characterized by a large increase of extracellular potassium concentration and prolonged subsequent electrical silencing of neurons. Waves of CSD arise spontaneously in various acute neurological settings, including migraine aura and ischemic stroke. Recently, we have reported that pan-inhibition of adrenergic receptors (AdRs) facilitates the normalization of extracellular potassium after acute photothrombotic stroke in mice. Here, we have extended that mechanistic study to ask whether AdR antagonists also modify the dynamics of KCl-induced CSD and post-CSD recovery in vivo. Spontaneous neural activity and KCl-induced CSD were visualized by cortex-wide transcranial Ca2+ imaging in G-CaMP7 transgenic mice. AdR antagonism decreased the recurrence of CSD waves and accelerated the post-CSD recovery of neural activity. Two-photon imaging revealed that astrocytes exhibited aberrant Ca2+ signaling after passage of the CSD wave. This astrocytic Ca2+ activity was diminished by the AdR antagonists. Furthermore, AdR pan-antagonism facilitated the normalization of the extracellular potassium level after CSD, which paralleled the recovery of neural activity. These observations add support to the proposal that neuroprotective effects of AdR pan-antagonism arise from accelerated normalization of extracellular K+ levels in the setting of acute brain injury.
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221
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Maruhashi T, Higashi Y. An overview of pharmacotherapy for cerebral vasospasm and delayed cerebral ischemia after subarachnoid hemorrhage. Expert Opin Pharmacother 2021; 22:1601-1614. [PMID: 33823726 DOI: 10.1080/14656566.2021.1912013] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Introduction: Survival from aneurysmal subarachnoid hemorrhage has increased in the past few decades. However, functional outcome after subarachnoid hemorrhage is still suboptimal. Delayed cerebral ischemia (DCI) is one of the major causes of morbidity.Areas covered: Mechanisms underlying vasospasm and DCI after aneurysmal subarachnoid hemorrhage and pharmacological treatment are summarized in this review.Expert opinion: Oral nimodine, an L-type dihydropyridine calcium channel blocker, is the only FDA-approved drug for the prevention and treatment of neurological deficits after aneurysmal subarachnoid hemorrhage. Fasudil, a potent Rho-kinase inhibitor, has also been shown to improve the clinical outcome and has been approved in some countries for use in patients with aneurysmal subarachnoid hemorrhage. Although other drugs, including nicardipine, cilostazol, statins, clazosentan, magnesium and heparin, have been expected to have beneficial effects on DCI, there has been no convincing evidence supporting the routine use of those drugs in patients with aneurysmal subarachnoid hemorrhage in clinical practice. Further elucidation of the mechanisms underlying DCI and the development of effective therapeutic strategies for DCI, including combination therapy, are necessary to further improve the functional outcome and mortality after subarachnoid hemorrhage.
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Affiliation(s)
- Tatsuya Maruhashi
- Department of Cardiovascular Regeneration and Medicine, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
| | - Yukihito Higashi
- Department of Cardiovascular Regeneration and Medicine, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan.,Division of Regeneration and Medicine, Medical Center for Translational and Clinical Research, Hiroshima University Hospital, Hiroshima, Japan
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Tamim I, Chung DY, de Morais AL, Loonen ICM, Qin T, Misra A, Schlunk F, Endres M, Schiff SJ, Ayata C. Spreading depression as an innate antiseizure mechanism. Nat Commun 2021; 12:2206. [PMID: 33850125 PMCID: PMC8044138 DOI: 10.1038/s41467-021-22464-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 03/15/2021] [Indexed: 12/16/2022] Open
Abstract
Spreading depression (SD) is an intense and prolonged depolarization in the central nervous systems from insect to man. It is implicated in neurological disorders such as migraine and brain injury. Here, using an in vivo mouse model of focal neocortical seizures, we show that SD may be a fundamental defense against seizures. Seizures induced by topical 4-aminopyridine, penicillin or bicuculline, or systemic kainic acid, culminated in SDs at a variable rate. Greater seizure power and area of recruitment predicted SD. Once triggered, SD immediately suppressed the seizure. Optogenetic or KCl-induced SDs had similar antiseizure effect sustained for more than 30 min. Conversely, pharmacologically inhibiting SD occurrence during a focal seizure facilitated seizure generalization. Altogether, our data indicate that seizures trigger SD, which then terminates the seizure and prevents its generalization.
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Affiliation(s)
- Isra Tamim
- Neurovascular Research Unit, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Charité-Universitätsmedizin Berlin, Klinik und Hochschulambulanz für Neurologie und Centrum für Schlaganfallforschung Berlin (CSB), Berlin, Germany
| | - David Y Chung
- Neurovascular Research Unit, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Andreia Lopes de Morais
- Neurovascular Research Unit, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Inge C M Loonen
- Neurovascular Research Unit, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Tao Qin
- Neurovascular Research Unit, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Amrit Misra
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Frieder Schlunk
- Charité-Universitätsmedizin Berlin, Klinik und Hochschulambulanz für Neurologie und Centrum für Schlaganfallforschung Berlin (CSB), Berlin, Germany
| | - Matthias Endres
- Charité-Universitätsmedizin Berlin, Klinik und Hochschulambulanz für Neurologie und Centrum für Schlaganfallforschung Berlin (CSB), Berlin, Germany
| | - Steven J Schiff
- Center for Neural Engineering, Departments of Engineering Science and Mechanics and Physics, The Pennsylvania State University, State College, PA, USA
| | - Cenk Ayata
- Neurovascular Research Unit, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
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223
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Masvidal-Codina E, Smith TM, Rathore D, Gao Y, Illa X, Prats-Alfonso E, Corro ED, Calia AB, Rius G, Martin-Fernandez I, Guger C, Reitner P, Villa R, Garrido JA, Guimerà-Brunet A, Wykes RC. Characterization of optogenetically-induced cortical spreading depression in awake mice using graphene micro-transistor arrays. J Neural Eng 2021; 18. [PMID: 33690187 DOI: 10.1088/1741-2552/abecf3] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 03/09/2021] [Indexed: 11/11/2022]
Abstract
Objective.The development of experimental methodology utilizing graphene micro-transistor arrays to facilitate and advance translational research into cortical spreading depression (CSD) in the awake brain.Approach.CSDs were reliably induced in awake nontransgenic mice using optogenetic methods. High-fidelity DC-coupled electrophysiological mapping of propagating CSDs was obtained using flexible arrays of graphene soultion-gated field-effect transistors (gSGFETs).Main results.Viral vectors targetted channelrhopsin expression in neurons of the motor cortex resulting in a transduction volume ⩾1 mm3. 5-10 s of continous blue light stimulation induced CSD that propagated across the cortex at a velocity of 3.0 ± 0.1 mm min-1. Graphene micro-transistor arrays enabled high-density mapping of infraslow activity correlated with neuronal activity suppression across multiple frequency bands during both CSD initiation and propagation. Localized differences in the CSD waveform could be detected and categorized into distinct clusters demonstrating the spatial resolution advantages of DC-coupled recordings. We exploited the reliable and repeatable induction of CSDs using this preparation to perform proof-of-principle pharmacological interrogation studies using NMDA antagonists. MK801 (3 mg kg-1) suppressed CSD induction and propagation, an effect mirrored, albeit transiently, by ketamine (15 mg kg-1), thus demonstrating this models' applicability as a preclinical drug screening platform. Finally, we report that CSDs could be detected through the skull using graphene micro-transistors, highlighting additional advantages and future applications of this technology.Significance.CSD is thought to contribute to the pathophysiology of several neurological diseases. CSD research will benefit from technological advances that permit high density electrophysiological mapping of the CSD waveform and propagation across the cortex. We report anin vivoassay that permits minimally invasive optogenetic induction, combined with multichannel DC-coupled recordings enabled by gSGFETs in the awake brain. Adoption of this technological approach could facilitate and transform preclinical investigations of CSD in disease relevant models.
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Affiliation(s)
- Eduard Masvidal-Codina
- Institut de Microelectrònica de Barcelona, IMB-CNM (CSIC), Esfera UAB, Bellaterra 08193, Spain.,Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Madrid 28029, Spain
| | - Trevor M Smith
- Department of Clinical and Experimental Epilepsy, Queen Square Institute of Neurology, University College London, London WC1N 3BG, United Kingdom
| | - Daman Rathore
- Department of Clinical and Experimental Epilepsy, Queen Square Institute of Neurology, University College London, London WC1N 3BG, United Kingdom
| | - Yunan Gao
- Department of Clinical and Experimental Epilepsy, Queen Square Institute of Neurology, University College London, London WC1N 3BG, United Kingdom
| | - Xavi Illa
- Institut de Microelectrònica de Barcelona, IMB-CNM (CSIC), Esfera UAB, Bellaterra 08193, Spain.,Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Madrid 28029, Spain
| | - Elisabet Prats-Alfonso
- Institut de Microelectrònica de Barcelona, IMB-CNM (CSIC), Esfera UAB, Bellaterra 08193, Spain.,Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Madrid 28029, Spain
| | - Elena Del Corro
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, Barcelona 08193, Spain
| | - Andrea Bonaccini Calia
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, Barcelona 08193, Spain
| | - Gemma Rius
- Institut de Microelectrònica de Barcelona, IMB-CNM (CSIC), Esfera UAB, Bellaterra 08193, Spain
| | - Iñigo Martin-Fernandez
- Institut de Microelectrònica de Barcelona, IMB-CNM (CSIC), Esfera UAB, Bellaterra 08193, Spain.,Universitat Autònoma de Barcelona, Bellaterra 08193, Spain
| | - Christoph Guger
- g.tec medical engineering GmbH, Guger Technologies OG, 8020 Graz, Austria
| | - Patrick Reitner
- g.tec medical engineering GmbH, Guger Technologies OG, 8020 Graz, Austria
| | - Rosa Villa
- Institut de Microelectrònica de Barcelona, IMB-CNM (CSIC), Esfera UAB, Bellaterra 08193, Spain.,Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Madrid 28029, Spain
| | - Jose A Garrido
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, Barcelona 08193, Spain.,ICREA, Barcelona 08010, Spain
| | - Anton Guimerà-Brunet
- Institut de Microelectrònica de Barcelona, IMB-CNM (CSIC), Esfera UAB, Bellaterra 08193, Spain.,Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Madrid 28029, Spain
| | - Rob C Wykes
- Department of Clinical and Experimental Epilepsy, Queen Square Institute of Neurology, University College London, London WC1N 3BG, United Kingdom.,Nanomedicine Lab, Faculty of Biology Medicine and Geoffrey Jefferson Brain Research Centre, University of Manchester, Manchester M13 9PT, United Kingdom
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224
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Rass V, Helbok R. How to diagnose delayed cerebral ischaemia and symptomatic vasospasm and prevent cerebral infarction in patients with subarachnoid haemorrhage. Curr Opin Crit Care 2021; 27:103-114. [PMID: 33405414 DOI: 10.1097/mcc.0000000000000798] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PURPOSE OF REVIEW Delayed cerebral ischaemia (DCI) complicates the clinical course of patients with subarachnoid haemorrhage (SAH) in 20--30% and substantially worsens outcome. In this review, we describe a multimodal diagnostic approach based on underlying mechanisms of DCI and provide treatment options with a special focus on the most recently published literature. RECENT FINDINGS Symptomatic vasospasm refers to clinical deterioration in the presence of vasospasm whereas DCI constitutes multiple causes. Pathophysiologic mechanisms underlying DCI range beyond large vessel vasospasm from neuroinflammation, to microthromboembolism, impaired cerebral autoregulation, cortical spreading depolarizations and many others. The current definition of DCI can be challenged by these mechanisms. We propose a pragmatic approach using a combination of clinical examination, cerebral ultrasonography, neuroimaging modalities and multimodal neuromonitoring to trigger therapeutic interventions in the presence of DCI. In addition to prophylactic nimodipine and management principles to improve oxygen delivery and decrease the brain metabolic demand, other specific interventions include permissive hypertension, intra-arterial application of calcium channel blockers and in selected patients angioplasty. SUMMARY The complex pathophysiology underlying DCI urges for a multimodal diagnostic approach triggering targeted interventions. Novel treatment concepts still have to be proven in large trials.
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Affiliation(s)
- Verena Rass
- Department of Neurology, Medical University of Innsbruck, Anichstrasse, Innsbruck, Austria
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225
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Neuromonitoring After Cardiac Arrest: Can Twenty-First Century Medicine Personalize Post Cardiac Arrest Care? Neurol Clin 2021; 39:273-292. [PMID: 33896519 DOI: 10.1016/j.ncl.2021.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Cardiac arrest survivors comprise a heterogeneous population, in which the etiology of arrest, systemic and neurologic comorbidities, and sequelae of post-cardiac arrest syndrome influence the severity of secondary brain injury. The degree of secondary neurologic injury can be modifiable and is influenced by factors that alter cerebral physiology. Neuromonitoring techniques provide tools for evaluating the evolution of physiologic variables over time. This article reviews the pathophysiology of hypoxic-ischemic brain injury, provides an overview of the neuromonitoring tools available to identify risk profiles for secondary brain injury, and highlights the importance of an individualized approach to post cardiac arrest care.
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226
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Schlabitz S, Monni L, Ragot A, Dipper-Wawra M, Onken J, Holtkamp M, Fidzinski P. Spatiotemporal Correlation of Epileptiform Activity and Gene Expression in vitro. Front Mol Neurosci 2021; 14:643763. [PMID: 33859552 PMCID: PMC8042243 DOI: 10.3389/fnmol.2021.643763] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 03/03/2021] [Indexed: 11/14/2022] Open
Abstract
Epileptiform activity alters gene expression in the central nervous system, a phenomenon that has been studied extensively in animal models. Here, we asked whether also in vitro models of seizures are in principle suitable to investigate changes in gene expression due to epileptiform activity and tested this hypothesis mainly in rodent and additionally in some human brain slices. We focused on three genes relevant for seizures and epilepsy: FOS proto-oncogene (c-Fos), inducible cAMP early repressor (Icer) and mammalian target of rapamycin (mTor). Seizure-like events (SLEs) were induced by 4-aminopyridine (4-AP) in rat entorhinal-hippocampal slices and by 4-AP/8 mM potassium in human temporal lobe slices obtained from surgical treatment of epilepsy. SLEs were monitored simultaneously by extracellular field potentials and intrinsic optical signals (IOS) for 1–4 h, mRNA expression was quantified by real time PCR. In rat slices, both duration of SLE exposure and SLE onset region were associated with increased expression of c-Fos and Icer while no such association was shown for mTor expression. Similar to rat slices, c-FOS induction in human tissue was increased in slices with epileptiform activity. Our results indicate that irrespective of limitations imposed by ex vivo conditions, in vitro models represent a suitable tool to investigate gene expression. Our finding is of relevance for the investigation of human tissue that can only be performed ex vivo. Specifically, it presents an important prerequisite for future studies on transcriptome-wide and cell-specific changes in human tissue with the goal to reveal novel candidates involved in the pathophysiology of epilepsy and possibly other CNS pathologies.
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Affiliation(s)
- Sophie Schlabitz
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Neurology with Experimental Neurology, Clinical and Experimental Epileptology, Berlin, Germany
| | - Laura Monni
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Neurology with Experimental Neurology, Clinical and Experimental Epileptology, Berlin, Germany
| | - Alienor Ragot
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Neurology with Experimental Neurology, Clinical and Experimental Epileptology, Berlin, Germany
| | - Matthias Dipper-Wawra
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Neurology with Experimental Neurology, Clinical and Experimental Epileptology, Berlin, Germany
| | - Julia Onken
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Neurosurgery, Berlin, Germany
| | - Martin Holtkamp
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Neurology with Experimental Neurology, Clinical and Experimental Epileptology, Berlin, Germany.,Epilepsy-Center Berlin-Brandenburg, Institute for Diagnostics of Epilepsy, Berlin, Germany
| | - Pawel Fidzinski
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Neurology with Experimental Neurology, Clinical and Experimental Epileptology, Berlin, Germany.,Epilepsy-Center Berlin-Brandenburg, Institute for Diagnostics of Epilepsy, Berlin, Germany.,Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, NeuroCure Cluster of Excellence, Neuroscience Research Center, Berlin, Germany
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227
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Tóth R, Farkas AE, Krizbai IA, Makra P, Bari F, Farkas E, Menyhárt Á. Astrocyte Ca 2+ Waves and Subsequent Non-Synchronized Ca 2+ Oscillations Coincide with Arteriole Diameter Changes in Response to Spreading Depolarization. Int J Mol Sci 2021; 22:ijms22073442. [PMID: 33810538 PMCID: PMC8037646 DOI: 10.3390/ijms22073442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/11/2021] [Accepted: 03/23/2021] [Indexed: 11/16/2022] Open
Abstract
Spreading depolarization (SD) is a wave of mass depolarization that causes profound perfusion changes in acute cerebrovascular diseases. Although the astrocyte response is secondary to the neuronal depolarization with SD, it remains to be explored how glial activity is altered after the passage of SD. Here, we describe post-SD high frequency astrocyte Ca2+ oscillations in the mouse somatosensory cortex. The intracellular Ca2+ changes of SR101 labeled astrocytes and the SD-related arteriole diameter variations were simultaneously visualized by multiphoton microscopy in anesthetized mice. Post-SD astrocyte Ca2+ oscillations were identified as Ca2+ events non-synchronized among astrocytes in the field of view. Ca2+ oscillations occurred minutes after the Ca2+ wave of SD. Furthermore, fewer astrocytes were involved in Ca2+ oscillations at a given time, compared to Ca2+ waves, engaging all astrocytes in the field of view simultaneously. Finally, our data confirm that astrocyte Ca2+ waves coincide with arteriolar constriction, while post-SD Ca2+ oscillations occur with the peak of the SD-related vasodilation. This is the first in vivo study to present the post-SD astrocyte Ca2+ oscillations. Our results provide novel insight into the spatio-temporal correlation between glial reactivity and cerebral arteriole diameter changes behind the SD wavefront.
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Affiliation(s)
- Réka Tóth
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged, Korányi fasor 9, 6720 Szeged, Hungary; (R.T.); (P.M.); (F.B.)
| | - Attila E. Farkas
- Neurovascular Unit Research Group, Molecular Neurobiology Research Unit, Institute of Biophysics, Biological Research Centre, Eötvös Loránd Research Network (ELKH), Temesvári krt 62, 6726 Szeged, Hungary; (A.E.F.); (I.A.K.)
| | - István A. Krizbai
- Neurovascular Unit Research Group, Molecular Neurobiology Research Unit, Institute of Biophysics, Biological Research Centre, Eötvös Loránd Research Network (ELKH), Temesvári krt 62, 6726 Szeged, Hungary; (A.E.F.); (I.A.K.)
- Institute of Life Sciences, Vasile Goldis Western University, Revolutiei Blvd no. 94, 310025 Arad, Romania
| | - Péter Makra
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged, Korányi fasor 9, 6720 Szeged, Hungary; (R.T.); (P.M.); (F.B.)
| | - Ferenc Bari
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged, Korányi fasor 9, 6720 Szeged, Hungary; (R.T.); (P.M.); (F.B.)
| | - Eszter Farkas
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged, Korányi fasor 9, 6720 Szeged, Hungary; (R.T.); (P.M.); (F.B.)
- Correspondence: (E.F.); (Á.M.); Tel.: +36-62-545-971 (E.F.); +36-62-545-364 (Á.M.)
| | - Ákos Menyhárt
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged, Korányi fasor 9, 6720 Szeged, Hungary; (R.T.); (P.M.); (F.B.)
- Correspondence: (E.F.); (Á.M.); Tel.: +36-62-545-971 (E.F.); +36-62-545-364 (Á.M.)
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228
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Different effects of monophasic pulses and biphasic pulses applied by a bipolar stimulation electrode in the rat hippocampal CA1 region. Biomed Eng Online 2021; 20:25. [PMID: 33750406 PMCID: PMC7942171 DOI: 10.1186/s12938-021-00862-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Accepted: 03/01/2021] [Indexed: 11/10/2022] Open
Abstract
Background Electrical pulse stimulations have been applied in brain for treating certain diseases such as movement disorders. High-frequency stimulations (HFS) of biphasic pulses have been used in clinic stimulations, such as deep brain stimulation (DBS), to minimize the risk of tissue damages caused by the electrical stimulations. However, HFS sequences of monophasic pulses have often been used in animal experiments for studying neuronal responses to the stimulations. It is not clear yet what the differences of the neuronal responses to the HFS of monophasic pulses from the HFS of biphasic pulses are. Methods To investigate the neuronal responses to the two types of pulses, orthodromic-HFS (O-HFS) and antidromic-HFS (A-HFS) of biphasic and monophasic pulses (1-min) were delivered by bipolar electrodes, respectively, to the Schaffer collaterals (i.e., afferent fibers) and the alveus fibers (i.e., efferent fibers) of the rat hippocampal CA1 region in vivo. Evoked population spikes of CA1 pyramidal neurons to the HFSs were recorded in the CA1 region. In addition, single pulses of antidromic- and orthodromic-test stimuli were applied before and after HFSs to evaluate the baseline and the recovery of neuronal activity, respectively. Results Spreading depression (SD) appeared during sequences of 200-Hz monophasic O-HFS with a high incidence (4/5), but did not appear during corresponding 200-Hz biphasic O-HFS (0/6). A preceding burst of population spikes appeared before the SD waveforms. Then, the SD propagated slowly, silenced neuronal firing temporarily and resulted in partial recovery of orthodromically evoked population spikes (OPS) after the end of O-HFS. No SD events appeared during the O-HFS with a lower frequency of 100 Hz of monophasic or biphasic pulses (0/5 and 0/6, respectively), neither during the A-HFS of 200-Hz pulses (0/9). The antidromically evoked population spikes (APS) after 200-Hz biphasic A-HFS recovered to baseline level within ~ 2 min. However, the APS only recovered partially after the 200-Hz A-HFS of monophasic pulses. Conclusions The O-HFS with a higher frequency of monophasic pulses can induce the abnormal neuron activity of SD and the A-HFS of monophasic pulses can cause a persisting attenuation of neuronal excitability, indicating neuronal damages caused by monophasic stimulations in brain tissues. The results provide guidance for proper stimulation protocols in clinic and animal experiments.
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229
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Intravenous milrinone for treatment of delayed cerebral ischaemia following subarachnoid haemorrhage: a pooled systematic review. Neurosurg Rev 2021; 44:3107-3124. [PMID: 33682040 DOI: 10.1007/s10143-021-01509-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 01/26/2021] [Accepted: 02/22/2021] [Indexed: 10/22/2022]
Abstract
Small trials have demonstrated promising results utilising intravenous milrinone for the treatment of delayed cerebral ischaemia (DCI) after subarachnoid haemorrhage (SAH). Here we summarise and contextualise the literature and discuss the future directions of intravenous milrinone for DCI. A systematic, pooled analysis of literature was performed in accordance with the PRISMA statement. Methodological rigour was analysed using the MINORS criteria. Extracted data included patient population; treatment protocol; and clinical, radiological, and functional outcome. The primary outcome was clinical resolution of DCI. Eight hundred eighteen patients from 10 single-centre, observational studies were identified. Half (n = 5) of the studies were prospective and all were at high risk of bias. Mean age was 52 years, and females (69%) outnumbered males. There was a similar proportion of low-grade (WFNS 1-2) (49.7%) and high-grade (WFNS 3-5) (50.3%) SAH. Intravenous milrinone was administered to 523/818 (63.9%) participants. Clinical resolution of DCI was achieved in 375/424 (88%), with similar rates demonstrated with intravenous (291/330, 88%) and combined intra-arterial-intravenous (84/94, 89%) therapy. Angiographic response was seen in 165/234 (71%) receiving intravenous milrinone. Hypotension (70/303, 23%) and hypokalaemia (31/287, 11%) were common drug effects. Four cases (0.5%) of drug intolerance occurred. Good functional outcome was achieved in 271/364 (74%) patients. Cerebral infarction attributable to DCI occurred in 47/250 (19%), with lower rates in asymptomatic spasm. Intravenous milrinone is a safe and feasible therapy for DCI. A signal for efficacy is demonstrated in small, low-quality trials. Future research should endeavour to establish the optimal protocol and dose, prior to a phase-3 study.
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230
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Petzold GC, Dreier JP. Spreading depolarization evoked by endothelin-1 is inhibited by octanol but not by carbenoxolone. BRAIN HEMORRHAGES 2021. [DOI: 10.1016/j.hest.2020.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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231
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Balança B, Desmurs L, Grelier J, Perret-Liaudet A, Lukaszewicz AC. DAMPs and RAGE Pathophysiology at the Acute Phase of Brain Injury: An Overview. Int J Mol Sci 2021; 22:ijms22052439. [PMID: 33670976 PMCID: PMC7957733 DOI: 10.3390/ijms22052439] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 02/17/2021] [Accepted: 02/23/2021] [Indexed: 12/14/2022] Open
Abstract
Early or primary injury due to brain aggression, such as mechanical trauma, hemorrhage or is-chemia, triggers the release of damage-associated molecular patterns (DAMPs) in the extracellular space. Some DAMPs, such as S100B, participate in the regulation of cell growth and survival but may also trigger cellular damage as their concentration increases in the extracellular space. When DAMPs bind to pattern-recognition receptors, such as the receptor of advanced glycation end-products (RAGE), they lead to non-infectious inflammation that will contribute to necrotic cell clearance but may also worsen brain injury. In this narrative review, we describe the role and ki-netics of DAMPs and RAGE at the acute phase of brain injury. We searched the MEDLINE database for “DAMPs” or “RAGE” or “S100B” and “traumatic brain injury” or “subarachnoid hemorrhage” or “stroke”. We selected original articles reporting data on acute brain injury pathophysiology, from which we describe DAMPs release and clearance upon acute brain injury, and the implication of RAGE in the development of brain injury. We will also discuss the clinical strategies that emerge from this overview in terms of biomarkers and therapeutic perspectives
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Affiliation(s)
- Baptiste Balança
- Department of Neurological Anesthesiology and Intensive Care Medicine, Hospices Civils de Lyon, Hôpital Pierre Wertheimer, 69500 Bron, France;
- Team TIGER, Lyon Neuroscience Research Centre, Inserm U1028, CNRS UMR 5292, 69500 Bron, France
- Correspondence: ; Tel.: +33-6-2391-0594
| | - Laurent Desmurs
- Clinical Chemistry and Molecular Biology Laboratory, Hospices Civils de Lyon, Hôpital Pierre Wertheimer, 69500 Bron, France; (L.D.); (A.P.-L.)
| | - Jérémy Grelier
- Department of Neurological Anesthesiology and Intensive Care Medicine, Hospices Civils de Lyon, Hôpital Pierre Wertheimer, 69500 Bron, France;
| | - Armand Perret-Liaudet
- Clinical Chemistry and Molecular Biology Laboratory, Hospices Civils de Lyon, Hôpital Pierre Wertheimer, 69500 Bron, France; (L.D.); (A.P.-L.)
- Team BIORAN, Lyon Neuroscience Research Centre, Inserm U1028, CNRS UMR 5292, 69500 Bron, France
| | - Anne-Claire Lukaszewicz
- Department of Neurological Anesthesiology and Intensive Care Medicine, Hospices Civils de Lyon, Hôpital Edouard Herriot, 69003 Lyon, France;
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Bohara S, Garg K, Singh Rajpal PM, Kasliwal M. Role of Cilostazol in Prevention of Vasospasm After Aneurysmal Subarachnoid Hemorrhage-A Systematic Review, Meta-Analysis, and Trial Sequential Analysis. World Neurosurg 2021; 150:161-170. [PMID: 33631387 DOI: 10.1016/j.wneu.2021.02.069] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/14/2021] [Accepted: 02/15/2021] [Indexed: 11/17/2022]
Abstract
OBJECTIVE Cerebral vasospasm is a common complication after aneurysmal subarachnoid hemorrhage (aSAH). Many drugs have been tried to mitigate cerebral vasospasm and delayed cerebral ischemia. Cilostazol, a selective inhibitor of phosphodiesterase 3, is a promising agent in preventing cerebral vasospasm and delayed cerebral ischemia after aSAH. The objective of this article was to ascertain the effect of cilostazol on cerebral vasospasm after aSAH by performing meta-analysis and trial sequential analysis. METHODS A systematic search of the literature was performed, and all the eligible randomized controlled trials were included in the meta-analysis and trial sequential analysis. RESULTS A total of 454 articles were identified using the search criteria. Six articles were selected for systematic review and the 4 randomized controlled trials were included in the meta-analysis. The pooled odds ratio for symptomatic vasospasm, new-onset infarct, and angiographic vasospasm was 0.35 (95% confidence interval [CI], 0.21-0.59; P < 0.0001), 0.38 (95% CI, 0.21-0.66; P = 0.0007) and 0.49 (95% CI, 0.31-0.80; P = 0.004), respectively. The pooled risk ratio for unfavorable outcome was 0.52 (95% CI, 0.37-0.74; P = 0.0003). CONCLUSIONS Cilostazol decreases the prevalence of symptomatic vasospasm, new-onset infarct, and angiographic vasospasm when administered after aSAH. Trial sequential analysis increased the precision of our results because the defined thresholds of effect were met by the available studies. However, further studies involving patients from other geographic areas are required to confirm the generalization of the results.
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Affiliation(s)
- Sandeep Bohara
- Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, India
| | - Kanwaljeet Garg
- Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, India.
| | | | - Manish Kasliwal
- Department of Neurological Surgery, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
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233
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Telles JPM, Welling LC, Coelho ACSDS, Rabelo NN, Teixeira MJ, Figueiredo EG. Cortical spreading depolarization and ketamine: a short systematic review. Neurophysiol Clin 2021; 51:145-151. [PMID: 33610431 DOI: 10.1016/j.neucli.2021.01.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/26/2021] [Accepted: 01/27/2021] [Indexed: 11/25/2022] Open
Abstract
INTRODUCTION Cortical spreading depolarization (SD) describes pathological waves characterized by an almost complete sustained depolarization of neurons and astrocytes that spreads throughout the cortex. In this study, we carried out a qualitative review of all available evidence, clinical and preclinical, on the use of ketamine in SD. METHODS We performed a systematic review of Medline, with no restrictions regarding publishing date or language, in search of articles reporting the use of ketamine in SD. The search string was composed of "ketamine," "spreading," "depolarization," and "depression" in both (AND) and (OR) combinations. RESULTS Twenty studies were included in the final synthesis. Many studies showed that ketamine effectively blocks SD in rats, swine, and humans. The first prospective randomized trial was published in 2018. Ten patients with severe traumatic brain injury or subarachnoid hemorrhage were enrolled, and ketamine showed a significant, dose-dependent effect on the reduction of SD. CONCLUSION The available evidence from preclinical studies is helping to translate the role of ketamine in blocking spreading depolarizations to clinical practice, in the settings of migraine with aura, traumatic brain injury, subarachnoid hemorrhage, and hemorrhagic and ischemic stroke. More randomized controlled trials are needed to determine whether interrupting the ketamine-blockable SDs effectively leads to an improvement in outcome and to assess the real occurrence of adverse effects.
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Affiliation(s)
- João Paulo Mota Telles
- Division of Neurosurgery, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HC-FMUSP), Brazil
| | | | | | - Nícollas Nunes Rabelo
- Division of Neurosurgery, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HC-FMUSP), Brazil
| | - Manoel Jacobsen Teixeira
- Division of Neurosurgery, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HC-FMUSP), Brazil
| | - Eberval Gadelha Figueiredo
- Division of Neurosurgery, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HC-FMUSP), Brazil.
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234
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Passlick S, Rose CR, Petzold GC, Henneberger C. Disruption of Glutamate Transport and Homeostasis by Acute Metabolic Stress. Front Cell Neurosci 2021; 15:637784. [PMID: 33603647 PMCID: PMC7884476 DOI: 10.3389/fncel.2021.637784] [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: 12/04/2020] [Accepted: 01/11/2021] [Indexed: 01/02/2023] Open
Abstract
High-affinity, Na+-dependent glutamate transporters are the primary means by which synaptically released glutamate is removed from the extracellular space. They restrict the spread of glutamate from the synaptic cleft into the perisynaptic space and reduce its spillover to neighboring synapses. Thereby, glutamate uptake increases the spatial precision of synaptic communication. Its dysfunction and the entailing rise of the extracellular glutamate concentration accompanied by an increased spread of glutamate result in a loss of precision and in enhanced excitation, which can eventually lead to neuronal death via excitotoxicity. Efficient glutamate uptake depends on a negative resting membrane potential as well as on the transmembrane gradients of the co-transported ions (Na+, K+, and H+) and thus on the proper functioning of the Na+/K+-ATPase. Consequently, numerous studies have documented the impact of an energy shortage, as occurring for instance during an ischemic stroke, on glutamate clearance and homeostasis. The observations range from rapid changes in the transport activity to altered expression of glutamate transporters. Notably, while astrocytes account for the majority of glutamate uptake under physiological conditions, they may also become a source of extracellular glutamate elevation during metabolic stress. However, the mechanisms of the latter phenomenon are still under debate. Here, we review the recent literature addressing changes of glutamate uptake and homeostasis triggered by acute metabolic stress, i.e., on a timescale of seconds to minutes.
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Affiliation(s)
- Stefan Passlick
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, Duesseldorf, Germany
| | - Gabor C Petzold
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.,Division of Vascular Neurology, University Hospital Bonn, Bonn, Germany
| | - Christian Henneberger
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany.,German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.,Institute of Neurology, University College London, London, United Kingdom
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235
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Fritch CD, Qeadan F, Shuttleworth CW, Carlson AP. Spreading depolarization occurs in repeating, recognizable, patient-specific patterns after human brain injury. Brain Inj 2021; 35:299-303. [PMID: 33529080 DOI: 10.1080/02699052.2020.1861480] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Background and Objective: Electrocorticographic (ECoG) measurement of spreading depolarization (SD) has led to significant advances in understanding of injury progression in neuro ICU patients. However, SD can be difficult to recognize in ECoG regions with high artifact. Heuristics for ECoG analysis within these regions would be highly valuable.Methods: Patients requiring craniotomy following subarachnoid hemorrhage, malignant hemispheric stroke, or traumatic brain injury were enrolled in this study. ECoG leads were placed intraoperatively and scoring of SDs was completed twice; once using traditional criteria and again with the intention of finding SD patterns. Utilizing covariance structures, graphical overlay and various measures surrounding DC shift, SDs were evaluated for patterns.Results: SD patterns were consistently observed and were unique to each patient and lead placement. No more than five different patterns were noted for any given patient, and statistical analysis utilizing covariance structures revealed high intra-pattern consistency.Conclusion: This validation of internal patient specific patterns offers more insight into ECoG readings of high artifact regions. This, in addition to traditional SD scoring heuristics, offers another scoring tool for the neuro-ICU care of patient experiencing SD. Furthermore, description of neurologic disease by its SD patterns may offer a new direction for precision medicine.
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Affiliation(s)
- Chanju D Fritch
- Department of Neurosurgery, University of New Mexico, Albuquerque, New Mexico, USA
| | - Fares Qeadan
- Department of Family and Preventive Medicine, University of Utah, Salt Lake City, Utah, USA
| | | | - Andrew P Carlson
- Department of Neurosurgery, University of New Mexico, Albuquerque, New Mexico, USA
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Schoknecht K, Kikhia M, Lemale CL, Liotta A, Lublinsky S, Mueller S, Boehm-Sturm P, Friedman A, Dreier JP. The role of spreading depolarizations and electrographic seizures in early injury progression of the rat photothrombosis stroke model. J Cereb Blood Flow Metab 2021; 41:413-430. [PMID: 32241203 PMCID: PMC7812510 DOI: 10.1177/0271678x20915801] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Spreading depolarization (SD) and seizures are pathophysiological events associated with cerebral ischemia. Here, we investigated their role for injury progression in the cerebral cortex. Cerebral ischemia was induced in anesthetized male Wistar rats using the photothrombosis (PT) stroke model. SD and spontaneous neuronal activity were recorded in the presence of either urethane or ketamine/xylazine anesthesia. Blood-brain barrier (BBB) permeability, cerebral perfusion, and cellular damage were assessed through a cranial window and repeated intravenous injection of fluorescein sodium salt and propidium iodide until 4 h after PT. Neuronal injury and early lesion volume were quantified by stereological cell counting and manual and automated assessment of ex vivo T2-weighted magnetic resonance imaging. Onset SDs originated at the thrombotic core and invaded neighboring cortex, whereas delayed SDs often showed opposite propagation patterns. Seizure induction by 4-aminopyridine caused no increase in lesion volume or neuronal injury in urethane-anesthetized animals. Ketamine/xylazine anesthesia was associated with a lower number of onset SDs, reduced lesion volume, and neuronal injury despite a longer duration of seizures. BBB permeability increase inversely correlated with the number of SDs at 3 and 4 h after PT. Our results provide further evidence that ketamine may counteract the early progression of ischemic injury.
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Affiliation(s)
- Karl Schoknecht
- Center for Stroke Research Berlin (CSB), Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Experimental Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Neuroscience Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Institute for Neurophysiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Carl-Ludwig-Institute for Physiology, Medical Faculty, University of Leipzig, Leipzig, Germany
| | - Majed Kikhia
- Department of Experimental Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Einstein Center for Neurosciences Berlin, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Coline L Lemale
- Center for Stroke Research Berlin (CSB), Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Experimental Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Agustin Liotta
- Neuroscience Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Institute for Neurophysiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Anesthesiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Svetlana Lublinsky
- Departments of Physiology & Cell Biology, Cognitive & Brain Sciences, the Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Susanne Mueller
- Center for Stroke Research Berlin (CSB), Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Experimental Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,NeuroCure Cluster of Excellence and Charité Core Facility 7T Experimental MRIs, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Philipp Boehm-Sturm
- Center for Stroke Research Berlin (CSB), Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Experimental Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,NeuroCure Cluster of Excellence and Charité Core Facility 7T Experimental MRIs, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Alon Friedman
- Departments of Physiology & Cell Biology, Cognitive & Brain Sciences, the Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel.,Department of Medical Neuroscience, Dalhousie University, Halifax, Canada
| | - Jens P Dreier
- Center for Stroke Research Berlin (CSB), Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Experimental Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Einstein Center for Neurosciences Berlin, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Bernstein Center for Computational Neuroscience Berlin, Humboldt-Universität zu Berlin, Germany
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237
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Candelario-Jalil E, Paul S. Impact of aging and comorbidities on ischemic stroke outcomes in preclinical animal models: A translational perspective. Exp Neurol 2021; 335:113494. [PMID: 33035516 PMCID: PMC7874968 DOI: 10.1016/j.expneurol.2020.113494] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 09/25/2020] [Accepted: 10/02/2020] [Indexed: 12/16/2022]
Abstract
Ischemic stroke is a highly complex and devastating neurological disease. The sudden loss of blood flow to a brain region due to an ischemic insult leads to severe damage to that area resulting in the formation of an infarcted tissue, also known as the ischemic core. This is surrounded by the peri-infarct region or penumbra that denotes the functionally impaired but potentially salvageable tissue. Thus, the penumbral tissue is the main target for the development of neuroprotective strategies to minimize the extent of ischemic brain damage by timely therapeutic intervention. Given the limitations of reperfusion therapies with recombinant tissue plasminogen activator or mechanical thrombectomy, there is high enthusiasm to combine reperfusion therapy with neuroprotective strategies to further reduce the progression of ischemic brain injury. Till date, a large number of candidate neuroprotective drugs have been identified as potential therapies based on highly promising results from studies in rodent ischemic stroke models. However, none of these interventions have shown therapeutic benefits in stroke patients in clinical trials. In this review article, we discussed the urgent need to utilize preclinical models of ischemic stroke that more accurately mimic the clinical conditions in stroke patients by incorporating aged animals and animal stroke models with comorbidities. We also outlined the recent findings that highlight the significant differences in stroke outcome between young and aged animals, and how major comorbid conditions such as hypertension, diabetes, obesity and hyperlipidemia dramatically increase the vulnerability of the brain to ischemic damage that eventually results in worse functional outcomes. It is evident from these earlier studies that including animal models of aging and comorbidities during the early stages of drug development could facilitate the identification of neuroprotective strategies with high likelihood of success in stroke clinical trials.
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Affiliation(s)
- Eduardo Candelario-Jalil
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA.
| | - Surojit Paul
- Department of Neurology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
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238
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Sueiras M, Thonon V, Santamarina E, Sánchez-Guerrero Á, Poca MA, Quintana M, Riveiro M, Sahuquillo J. Cortical Spreading Depression Phenomena Are Frequent in Ischemic and Traumatic Penumbra: A Prospective Study in Patients With Traumatic Brain Injury and Large Hemispheric Ischemic Stroke. J Clin Neurophysiol 2021; 38:47-55. [PMID: 31702708 DOI: 10.1097/wnp.0000000000000648] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
PURPOSE Spreading depolarization (SD) phenomena are waves of neuronal depolarization, which propagate slowly at a velocity of 1 to 5 mm/minute and can occur in patients with ischemic or hemorrhagic stroke, traumatic brain injury, and migraine with aura. They form part of secondary injury, occurring after spreading ischemia. The purposes of this study were to describe the frequency and characteristics of SD phenomena and to define whether a correlation existed between SD and outcome in a group of patients with TBI and large hemispheric ischemic stroke. METHODS This was a prospective observational study of 39 adult patients, 17 with malignant middle cerebral artery infarction and 22 with moderate or severe traumatic brain injury, who underwent decompressive craniectomy and multimodal neuromonitoring including electrocorticography. Identification, classification, and interpretation of SDs were performed using the published recommendations from the Cooperative Study on Brain Injury Depolarization group. The outcomes assessed were functional disability at 6 and 12 months after injury, according to the extended Glasgow outcome scale, Barthel index, and modified Rankin scale. RESULTS Four hundred eighty-three SDs were detected, in 58.9% of the patients. Spreading depolarizations were more common, particularly the isoelectric SD type, in patients with malignant middle cerebral artery infarction (P < 0.04). In 65.21% of patients with SDs on electrocorticography, the "peak" day of depolarization was day 0 (the first 24 hours of recording). Spreading depolarization convulsions were present in 26.08% of patients with SDs. Patients with more SDs and higher depolarization indices scored worse on extended Glasgow outcome scale (6 months) and Barthel index (6 and 12 months) (P < 0.05). CONCLUSIONS Evidence on SD phenomena is important to ensure continued progress in understanding their pathophysiology, in the search for therapeutic targets to avoid additional damage from these secondary injuries.
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Affiliation(s)
- Maria Sueiras
- Department of Clinical Neurophysiology, Vall d'Hebron University Hospital, Barcelona, Spain
- Neurotrauma and Neurosurgery Research Unit (UNINN), Vall d'Hebron Research Institute (VHIR), Barcelona, Spain
- Universitat Autònoma de Barcelona (UAB), Barcelona, Spain
| | - Vanessa Thonon
- Department of Clinical Neurophysiology, Vall d'Hebron University Hospital, Barcelona, Spain
| | - Estevo Santamarina
- Epilepsy Unit, Department of Neurology, Vall d'Hebron University Hospital, Barcelona, Spain
| | - Ángela Sánchez-Guerrero
- Neurotrauma and Neurosurgery Research Unit (UNINN), Vall d'Hebron Research Institute (VHIR), Barcelona, Spain
| | - Maria A Poca
- Neurotrauma and Neurosurgery Research Unit (UNINN), Vall d'Hebron Research Institute (VHIR), Barcelona, Spain
- Universitat Autònoma de Barcelona (UAB), Barcelona, Spain
- Department of Neurosurgery, Vall d'Hebron University Hospital, Barcelona, Spain ; and
| | - Manuel Quintana
- Epilepsy Unit, Department of Neurology, Vall d'Hebron University Hospital, Barcelona, Spain
| | - Marilyn Riveiro
- Neurotrauma Intensive Care Unit, Vall d'Hebron University Hospital, Barcelona, Spain
| | - Juan Sahuquillo
- Neurotrauma and Neurosurgery Research Unit (UNINN), Vall d'Hebron Research Institute (VHIR), Barcelona, Spain
- Universitat Autònoma de Barcelona (UAB), Barcelona, Spain
- Department of Neurosurgery, Vall d'Hebron University Hospital, Barcelona, Spain ; and
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239
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Etminan N, Macdonald RL. Neurovascular disease, diagnosis, and therapy: Subarachnoid hemorrhage and cerebral vasospasm. HANDBOOK OF CLINICAL NEUROLOGY 2021; 176:135-169. [PMID: 33272393 DOI: 10.1016/b978-0-444-64034-5.00009-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The worldwide incidence of spontaneous subarachnoid hemorrhage is about 6.1 per 100,000 cases per year (Etminan et al., 2019). Eighty-five percent of cases are due to intracranial aneurysms. The mean age of those affected is 55 years, and two-thirds of the patients are female. The prognosis is related mainly to the neurologic condition after the subarachnoid hemorrhage and the age of the patient. Overall, 15% of patients die before reaching the hospital, another 20% die within 30 days, and overall 75% are dead or remain disabled. Case fatality has declined by 17% over the last 3 decades. Despite the improvement in outcome probably due to improved diagnosis, early aneurysm repair, administration of nimodipine, and advanced intensive care support, the outcome is not very good. Even among survivors, 75% have permanent cognitive deficits, mood disorders, fatigue, inability to return to work, and executive dysfunction and are often unable to return to their premorbid level of functioning. The key diagnostic test is computed tomography, and the treatments that are most strongly supported by scientific evidence are to undertake aneurysm repair in a timely fashion by endovascular coiling rather than neurosurgical clipping when feasible and to administer enteral nimodipine. The most common complications are aneurysm rebleeding, hydrocephalus, delayed cerebral ischemia, and medical complications (fever, anemia, and hyperglycemia). Management also probably is optimized by neurologic intensive care units and multidisciplinary teams.
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Affiliation(s)
- Nima Etminan
- Department of Neurosurgery, University Hospital Mannheim, University of Heidelberg, Mannheim, Germany
| | - R Loch Macdonald
- Department of Neurological Surgery, University of California San Francisco, San Francisco, CA, United States.
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240
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Zhaba WD, Deji QZ, Deng HJ, Han YL, Gao SQ, Liu XL, Zhou ML. Retinal hypoxia after experimental subarachnoid hemorrhage. Neurosci Lett 2020; 742:135554. [PMID: 33352284 DOI: 10.1016/j.neulet.2020.135554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/17/2020] [Accepted: 12/02/2020] [Indexed: 10/22/2022]
Abstract
BACKGROUND AND PURPOSE The patients who survive subarachnoid hemorrhage (SAH) often have long-term neurological complications. There are no reports about the pathological change of retina after SAH. METHODS An experimental model of SAH was established by injecting autologous blood into the prechiasmatic cistern of Sprague-Dawley rats. Hematoxylin and eosin (HE) staining was performed to show the alternation of morphology in retina after SAH. To detect the retinal new vessels (NVs), CD31 was labelled by immunofluorescence and immunohistochemistry. The time-course expressions of vascular endothelial growth factor (VEGF)-A and hypoxia-inducible factor-1α (HIF-1 α) was also revealed by Western blot analysis. RESULTS A clear reduction of retinal ganglion cells (RGCs) was noticed after SAH. The immunofluorescence and immunohistochemical staining of CD31 reveals a large number of NVs in RGC layer after SAH compared with the normal controls. The level of VEGF-A in the retina after SAH was increased and peaked at 12h and 14 d. The expression of HIF-1α in the retina increased as early as 3 h after SAH, reached a peak at 12 h after SAH. CONCLUSIONS The results showed that SAH induced the retina hypoxia resulting in the reduction of RGCs, increase of NVs and activation of NVs related HIF-1α/VEGF-A pathway.
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Affiliation(s)
- Wang-Dui Zhaba
- Department of Neurosurgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Qu-Zhen Deji
- Department of Ophthalmology, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Hong-Ji Deng
- Department of Neurosurgery, The First Affiliated Hospital, Guangxi Medical University, Nanning, Guangxi, China
| | - Yan-Ling Han
- Department of Neurosurgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Sheng-Qing Gao
- Department of Neurosurgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Xi-Lin Liu
- Graduate School of Wannan Medical College, Wuhu, Anhui, China
| | - Meng-Liang Zhou
- Department of Neurosurgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, China.
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241
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M. Tóth O, Menyhárt Á, Frank R, Hantosi D, Farkas E, Bari F. Tissue Acidosis Associated with Ischemic Stroke to Guide Neuroprotective Drug Delivery. BIOLOGY 2020; 9:biology9120460. [PMID: 33322264 PMCID: PMC7764344 DOI: 10.3390/biology9120460] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 12/02/2020] [Accepted: 12/07/2020] [Indexed: 12/14/2022]
Abstract
Simple Summary Ischemic stroke is caused by the blockade of a blood vessel in the brain. Consequently, the brain region supplied by the blocked vessel suffers brain damage and becomes acidic. Here we provide a summary of the causes and consequences of acid accumulation in the brain tissue. Ischemic stroke requires immediate medical attention to minimize the damage of brain tissue, and to save function. It would be desirable for the medical treatment to target the site of injury selectively, to enrich the site of ongoing injury with the protective agent, and to avoid undesirable side effects at the same time. We propose that acid accumulation at the sight of brain tissue injury can be used to delineate the region that would benefit most from medical treatment. Tiny drug carriers known as nanoparticles may be loaded with drugs that protect the brain tissue. These nanoparticles may be designed to release their drug cargo in response to an acidic environment. This would ensure that the therapeutic agent is directed selectively to the site where it is needed. Ultimately, this approach may offer a new way to treat stroke patients with the hope of more effective therapy, and better stroke outcome. Abstract Ischemic stroke is a leading cause of death and disability worldwide. Yet, the effective therapy of focal cerebral ischemia has been an unresolved challenge. We propose here that ischemic tissue acidosis, a sensitive metabolic indicator of injury progression in cerebral ischemia, can be harnessed for the targeted delivery of neuroprotective agents. Ischemic tissue acidosis, which represents the accumulation of lactic acid in malperfused brain tissue is significantly exacerbated by the recurrence of spreading depolarizations. Deepening acidosis itself activates specific ion channels to cause neurotoxic cellular Ca2+ accumulation and cytotoxic edema. These processes are thought to contribute to the loss of the ischemic penumbra. The unique metabolic status of the ischemic penumbra has been exploited to identify the penumbra zone with imaging tools. Importantly, acidosis in the ischemic penumbra may also be used to guide therapeutic intervention. Agents with neuroprotective promise are suggested here to be delivered selectively to the ischemic penumbra with pH-responsive smart nanosystems. The administered nanoparticels release their cargo in acidic tissue environment, which reliably delineates sites at risk of injury. Therefore, tissue pH-targeted drug delivery is expected to enrich sites of ongoing injury with the therapeutical agent, without the risk of unfavorable off-target effects.
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242
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Ding X, Peng D. Transient Global Amnesia: An Electrophysiological Disorder Based on Cortical Spreading Depression-Transient Global Amnesia Model. Front Hum Neurosci 2020; 14:602496. [PMID: 33363460 PMCID: PMC7753037 DOI: 10.3389/fnhum.2020.602496] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 11/17/2020] [Indexed: 01/09/2023] Open
Abstract
Transient global amnesia (TGA) is a benign memory disorder with etiologies that have been debated for a long time. The prevalence of stressful events before a TGA attack makes it hard to overlook these precipitating factors, given that stress has the potential to organically effect the brain. Cortical spreading depression (CSD) was proposed as a possible cause decades ago. Being a regional phenomenon, CSD seems to affect every aspect of the micro-mechanism in maintaining the homeostasis of the central nervous system (CNS). Corresponding evidence regarding hemodynamic and morphological changes from TGA and CSD have been accumulated separately, but the resemblance between the two has not been systematically explored so far, which is surprising especially considering that CSD had been confirmed to cause secondary damage in the human brain. Thus, by deeply delving into the anatomic and electrophysiological properties of the CNS, the CSD-TGA model may render insights into the basic pathophysiology behind the façade of the enigmatic clinical presentation.
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Affiliation(s)
- Xuejiao Ding
- Department of Neurology, China-Japan Friendship Hospital, Beijing, China
- Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Dantao Peng
- Department of Neurology, China-Japan Friendship Hospital, Beijing, China
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243
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Jaquins-Gerstl A, Michael AC. Dexamethasone-Enhanced Microdialysis and Penetration Injury. Front Bioeng Biotechnol 2020; 8:602266. [PMID: 33364231 PMCID: PMC7752925 DOI: 10.3389/fbioe.2020.602266] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 11/11/2020] [Indexed: 01/25/2023] Open
Abstract
Microdialysis probes, electrochemical microsensors, and neural prosthetics are often used for in vivo monitoring, but these are invasive devices that are implanted directly into brain tissue. Although the selectivity, sensitivity, and temporal resolution of these devices have been characterized in detail, less attention has been paid to the impact of the trauma they inflict on the tissue or the effect of any such trauma on the outcome of the measurements they are used to perform. Factors affecting brain tissue reaction to the implanted devices include: the mechanical trauma during insertion, the foreign body response, implantation method, and physical properties of the device (size, shape, and surface characteristics. Modulation of the immune response is an important step toward making these devices with reliable long-term performance. Local release of anti-inflammatory agents such as dexamethasone (DEX) are often used to mitigate the foreign body response. In this article microdialysis is used to locally deliver DEX to the surrounding brain tissue. This work discusses the immune response resulting from microdialysis probe implantation. We briefly review the principles of microdialysis and the applications of DEX with microdialysis in (i) neuronal devices, (ii) dopamine and fast scan cyclic voltammetry, (iii) the attenuation of microglial cells, (iv) macrophage polarization states, and (v) spreading depolarizations. The difficulties and complexities in these applications are herein discussed.
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244
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Hecht N, Schrammel M, Neumann K, Müller MM, Dreier JP, Vajkoczy P, Woitzik J. Perfusion-Dependent Cerebral Autoregulation Impairment in Hemispheric Stroke. Ann Neurol 2020; 89:358-368. [PMID: 33219550 DOI: 10.1002/ana.25963] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 11/18/2020] [Accepted: 11/18/2020] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Loss of cerebral autoregulation (CA) plays a key role in secondary neurologic injury. However, the regional distribution of CA impairment after acute cerebral injury remains unclear because, in clinical practice, CA is only assessed within a limited compartment. Here, we performed large-scale regional mapping of cortical perfusion and CA in patients undergoing decompressive surgery for malignant hemispheric stroke. METHODS In 24 patients, autoregulation over the affected hemisphere was calculated based on direct, 15 to 20-minute cortical perfusion measurement with intraoperative laser speckle imaging and mean arterial blood pressure (MAP) recording. Cortical perfusion was normalized against noninfarcted tissue and 6 perfusion categories from 0% to >100% were defined. The interaction between cortical perfusion and MAP was estimated using a linear random slope model and Pearson correlation. RESULTS Cortical perfusion and CA impairment were heterogeneously distributed across the entire hemisphere. The degree of CA impairment was significantly greater in areas with critical hypoperfusion (40-60%: 0.42% per mmHg and 60-80%: 0.46% per mmHg) than in noninfarcted (> 100%: 0.22% per mmHg) or infarcted (0-20%: 0.29% per mmHg) areas (*p < 0.001). Pearson correlation confirmed greater CA impairment at critically reduced perfusion (20-40%: r = 0.67; 40-60%: r = 0.68; and 60-80%: r = 0.68) compared to perfusion > 100% (r = 0.36; *p < 0.05). Tissue integrity had no impact on the degree of CA impairment. INTERPRETATION In hemispheric stroke, CA is impaired across the entire hemisphere to a variable extent. Autoregulation impairment was greatest in hypoperfused and potentially viable tissue, suggesting that precise localization of such regions is essential for effective tailoring of perfusion pressure-based treatment strategies. ANN NEUROL 2021;89:358-368.
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Affiliation(s)
- Nils Hecht
- Department of Neurosurgery, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Center for Stroke Research Berlin (CSB), Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Max Schrammel
- Department of Neurosurgery, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Center for Stroke Research Berlin (CSB), Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Neurosurgery, University of Oldenburg, Oldenburg, Germany
| | - Konrad Neumann
- Institute for Biometry and Clinical Epidemiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Marc-Michael Müller
- Department of Neurosurgery, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Center for Stroke Research Berlin (CSB), Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Anesthesiology, University of Schleswig-Holstein, Kiel, Germany
| | - Jens P Dreier
- Center for Stroke Research Berlin (CSB), Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Experimental Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany.,Einstein Center for Neurosciences Berlin, Berlin, Germany
| | - Peter Vajkoczy
- Department of Neurosurgery, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Center for Stroke Research Berlin (CSB), Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Johannes Woitzik
- Department of Neurosurgery, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Center for Stroke Research Berlin (CSB), Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Neurosurgery, University of Oldenburg, Oldenburg, Germany
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245
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Varga DP, Menyhárt Á, Pósfai B, Császár E, Lénárt N, Cserép C, Orsolits B, Martinecz B, Szlepák T, Bari F, Farkas E, Dénes Á. Microglia alter the threshold of spreading depolarization and related potassium uptake in the mouse brain. J Cereb Blood Flow Metab 2020; 40:S67-S80. [PMID: 31987008 PMCID: PMC7687034 DOI: 10.1177/0271678x19900097] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Selective elimination of microglia from the brain was shown to dysregulate neuronal Ca2+ signaling and to reduce the incidence of spreading depolarization (SD) during cerebral ischemia. However, the mechanisms through which microglia interfere with SD remained unexplored. Here, we identify microglia as essential modulators of the induction and evolution of SD in the physiologically intact brain in vivo. Confocal- and super-resolution microscopy revealed that a series of SDs induced rapid morphological changes in microglia, facilitated microglial process recruitment to neurons and increased the density of P2Y12 receptors (P2Y12R) on recruited microglial processes. In line with this, depolarization and hyperpolarization during SD were microglia- and P2Y12R-dependent. An absence of microglia was associated with altered potassium uptake after SD and increased the number of c-fos-positive neurons, independently of P2Y12R. Thus, the presence of microglia is likely to be essential to maintain the electrical elicitation threshold and to support the full evolution of SD, conceivably by interfering with the extracellular potassium homeostasis of the brain through sustaining [K+]e re-uptake mechanisms.
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Affiliation(s)
- Dániel P Varga
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Ákos Menyhárt
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Balázs Pósfai
- Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary.,Szentágothai János Doctoral School of Neuroscience, Semmelweis University, Budapest, Hungary
| | - Eszter Császár
- Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary.,Szentágothai János Doctoral School of Neuroscience, Semmelweis University, Budapest, Hungary
| | - Nikolett Lénárt
- Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Csaba Cserép
- Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Barbara Orsolits
- Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Bernadett Martinecz
- Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Tamás Szlepák
- Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary.,Szentágothai János Doctoral School of Neuroscience, Semmelweis University, Budapest, Hungary
| | - Ferenc Bari
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Eszter Farkas
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Ádám Dénes
- Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
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246
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High doses of ketamine to improve neuronal edema in subarachnoid hemorrhage: we should consider other undesirable organ targets. Crit Care 2020; 24:362. [PMID: 32552903 PMCID: PMC7304164 DOI: 10.1186/s13054-020-03004-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 05/19/2020] [Indexed: 01/22/2023] Open
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247
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Bu F, Yuan M, Ma D, Zhu Y, Wang M. Inhibition of NR2A reduces calcitonin gene-related peptide gene expression induced by cortical spreading depression in rat amygdala. Neuropeptides 2020; 84:102097. [PMID: 33059243 DOI: 10.1016/j.npep.2020.102097] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 10/04/2020] [Accepted: 10/06/2020] [Indexed: 01/25/2023]
Abstract
Despite robust evidence on the role of calcitonin gene-related peptide (CGRP) in migraine via both central and peripheral actions, relatively less is known about how CGRP in the limbic system is involved in migraine progression. This study investigated whether CGRP production machinery exists in the two key limbic regions including hippocampus and amygdala using cortical spreading depression (CSD) as a model of migraine and whether such alteration by CSD is sensitive to N-methyl-d-aspartate (NMDA) receptor regulation in rats. A single or repetitive CSD was induced by topical application of KCl and monitored using electrophysiological methods. The NR2A-containing NMDA receptor antagonist, NVP-AAM077, or its vehicle, was perfused into the contralateral cerebroventricular ventricle of rat. Quantitative PCR was used to measure CGRP mRNA levels in the ipsilateral and contralateral hippocampus and amygdala after CSD events and compared to respective sham treatments. The results showed that neither a single CSD nor repetitive CSD affected CGRP mRNA levels in both the contralateral and ipsilateral hippocampus at 24 h post CSD induction. Differently, significant elevation of CGRP gene expression was observed in the ipsilateral amygdala at 24 h post multiple CSD, but not contralateral side, and not post-single CSD. Further results showed that the CSD-induced CGRP gene expression in the amygdala was markedly reduced by NVP-AAM077 and this reduction corresponded to a reduced cortical susceptibility to CSD in rats. We conclude that repetitive CSD events induce CGRP gene expression in amygdala, which is sensitive to NR2A regulation.
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Affiliation(s)
- Fan Bu
- Department of Biological Sciences, Centre for Neuroscience, Xi'an Jiaotong-Liverpool University, Suzhou, China
| | - Mingming Yuan
- Department of Biological Sciences, Centre for Neuroscience, Xi'an Jiaotong-Liverpool University, Suzhou, China
| | - Dongqing Ma
- Department of Biological Sciences, Centre for Neuroscience, Xi'an Jiaotong-Liverpool University, Suzhou, China
| | - Ying Zhu
- Department of Biological Sciences, Centre for Neuroscience, Xi'an Jiaotong-Liverpool University, Suzhou, China
| | - Minyan Wang
- Department of Biological Sciences, Centre for Neuroscience, Xi'an Jiaotong-Liverpool University, Suzhou, China.
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248
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Chen S, Xu P, Fang Y, Lenahan C. The Updated Role of the Blood Brain Barrier in Subarachnoid Hemorrhage: From Basic and Clinical Studies. Curr Neuropharmacol 2020; 18:1266-1278. [PMID: 32928088 PMCID: PMC7770644 DOI: 10.2174/1570159x18666200914161231] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/05/2020] [Accepted: 08/05/2020] [Indexed: 12/15/2022] Open
Abstract
Subarachnoid hemorrhage (SAH) is a type of hemorrhagic stroke associated with high mortality and morbidity. The blood-brain-barrier (BBB) is a structure consisting primarily of cerebral microvascular endothelial cells, end feet of astrocytes, extracellular matrix, and pericytes. Post-SAH pathophysiology included early brain injury and delayed cerebral ischemia. BBB disruption was a critical mechanism of early brain injury and was associated with other pathophysiological events. These pathophysiological events may propel the development of secondary brain injury, known as delayed cerebral ischemia. Imaging advancements to measure BBB after SAH primarily focused on exploring innovative methods to predict clinical outcome, delayed cerebral ischemia, and delayed infarction related to delayed cerebral ischemia in acute periods. These predictions are based on detecting abnormal changes in BBB permeability. The parameters of BBB permeability are described by changes in computed tomography (CT) perfusion and magnetic resonance imaging (MRI). Kep seems to be a stable and sensitive indicator in CT perfusion, whereas Ktrans is a reliable parameter for dynamic contrast-enhanced MRI. Future prediction models that utilize both the volume of BBB disruption and stable parameters of BBB may be a promising direction to develop practical clinical tools. These tools could provide greater accuracy in predicting clinical outcome and risk of deterioration. Therapeutic interventional exploration targeting BBB disruption is also promising, considering the extended duration of post-SAH BBB disruption.
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Affiliation(s)
- Sheng Chen
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou,
Zhejiang Province, China
| | - PengLei Xu
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou,
Zhejiang Province, China
| | - YuanJian Fang
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou,
Zhejiang Province, China
| | - Cameron Lenahan
- Burrell College of Osteopathic Medicine, Las Cruces, NM, USA,Center for Neuroscience Research, School of Medicine, Loma Linda University, Loma Linda, CA, USA
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249
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Sadowska M, Mehlhorn C, Średniawa W, Szewczyk ŁM, Szlachcic A, Urban P, Winiarski M, Jabłonka JA. Spreading Depressions and Periinfarct Spreading Depolarizations in the Context of Cortical Plasticity. Neuroscience 2020; 453:81-101. [PMID: 33227236 DOI: 10.1016/j.neuroscience.2020.10.032] [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: 12/21/2019] [Revised: 10/26/2020] [Accepted: 10/27/2020] [Indexed: 11/17/2022]
Abstract
Studies of cortical function-recovery require a comparison between normal and post-stroke conditions that lead to changes in cortical metaplasticity. Focal cortical stroke impairs experience-dependent plasticity in the neighboring somatosensory cortex and usually evokes periinfarct depolarizations (PiDs) - spreading depression-like waves. Experimentally induced spreading depressions (SDs) affect gene expression and some of these changes persist for at least 30 days. In this study we compare the effects of non-stroke depolarizations that impair cortical experience-dependent plasticity to the effects of stroke, by inducing experience-dependent plasticity in rats with SDs or PiDs by a month of contralateral partial whiskers deprivation. We found that whiskers' deprivation after SDs resulted in normal cortical representation enlargement suggesting that SDs and PiDs depolarization have no influence on experience-dependent plasticity cortical map reorganization. PiDs and the MMP-9, -3, -2 or COX-2 proteins, which are assumed to influence metaplasticity in rats after stroke were compared between SDs induced by high osmolarity KCl solution and the PiDs that followed cortical photothrombotic stroke (PtS). We found that none of these factors directly caused cortical post-stroke metaplasticity changes. The only significant difference between stoke and induced SD was a greater imbalance in interhemispheric activity equilibrium after stroke. The interhemispheric interactions that were modified by stroke may therefore be promising targets for future studies of post-stroke experience-dependent plasticity and of recuperation studies.
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Affiliation(s)
- Maria Sadowska
- Laboratory of Animal Physiology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | | | - Władysław Średniawa
- Laboratory of Neuroinformatics, Nencki Institute of Experimental Biology of PAS, Warsaw, Poland; Laboratory of Animal Physiology, Faculty of Biology, University of Warsaw, Warsaw, Poland; College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, Warsaw, Poland
| | - Łukasz M Szewczyk
- Laboratory of Molecular Neurobiology, Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - Aleksandra Szlachcic
- Laboratory of Animal Physiology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Paulina Urban
- Laboratory of Functional and Structural Genomics, Center of New Technologies, University of Warsaw, Warsaw, Poland; College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, Warsaw, Poland
| | - Maciej Winiarski
- Laboratory of Emotions Neurobiology, Nencki Institute of Experimental Biology, PAS, Warsaw, Poland
| | - Jan A Jabłonka
- Laboratory of Animal Physiology, Faculty of Biology, University of Warsaw, Warsaw, Poland.
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250
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Min Rivas F, Liu J, Martell BC, Du T, Mestre H, Nedergaard M, Tithof J, Thomas JH, Kelley DH. Surface periarterial spaces of the mouse brain are open, not porous. J R Soc Interface 2020; 17:20200593. [PMID: 33171075 DOI: 10.1098/rsif.2020.0593] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Fluid-dynamic models of the flow of cerebrospinal fluid in the brain have treated the perivascular spaces either as open (without internal solid obstacles) or as porous. Here, we present experimental evidence that pial (surface) periarterial spaces in mice are essentially open. (1) Paths of particles in the perivascular spaces are smooth, as expected for viscous flow in an open vessel, not diffusive, as expected for flow in a porous medium. (2) Time-averaged velocity profiles in periarterial spaces agree closely with theoretical profiles for viscous flow in realistic models, but not with the nearly uniform profiles expected for porous medium. Because these spaces are open, they have much lower hydraulic resistance than if they were porous. To demonstrate, we compute hydraulic resistance for realistic periarterial spaces, both open and porous, and show that the resistance of the porous spaces are greater, typically by a factor of a hundred or more. The open nature of these periarterial spaces allows significantly greater flow rates and more efficient removal of metabolic waste products.
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Affiliation(s)
- Fatima Min Rivas
- Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627, USA
| | - Jia Liu
- Department of Mechanical Engineering, University of Rochester, Rochester, NY 14627, USA
| | - Benjamin C Martell
- Department of Mechanical Engineering, University of Rochester, Rochester, NY 14627, USA.,Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Ting Du
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Humberto Mestre
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA.,Department of Neurology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA.,Department of Neurology, University of Rochester Medical Center, Rochester, NY 14642, USA.,Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
| | - Jeffrey Tithof
- Department of Mechanical Engineering, University of Rochester, Rochester, NY 14627, USA.,Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
| | - John H Thomas
- Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627, USA.,Department of Mechanical Engineering, University of Rochester, Rochester, NY 14627, USA
| | - Douglas H Kelley
- Department of Mechanical Engineering, University of Rochester, Rochester, NY 14627, USA
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