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Leppert J, Küchler J, Wagner A, Hinselmann N, Ditz C. Prospective Observational Study of Volatile Sedation with Sevoflurane After Aneurysmal Subarachnoid Hemorrhage Using the Sedaconda Anesthetic Conserving Device. Neurocrit Care 2024; 41:498-510. [PMID: 38485879 DOI: 10.1007/s12028-024-01959-7] [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: 11/06/2023] [Accepted: 02/09/2024] [Indexed: 06/22/2024]
Abstract
BACKGROUND Volatile sedation is still used with caution in patients with acute brain injury because of safety concerns. We analyzed the effects of sevoflurane sedation on systemic and cerebral parameters measured by multimodal neuromonitoring in patients after aneurysmal subarachnoid hemorrhage (aSAH) with normal baseline intracranial pressure (ICP). METHODS In this prospective observational study, we analyzed a 12-h period before and after the switch from intravenous to volatile sedation with sevoflurane using the Sedaconda Anesthetic Conserving Device with a target Richmond Agitation Sedation Scale score of - 5 to - 4. ICP, cerebral perfusion pressure (CPP), brain tissue oxygenation (PBrO2), metabolic values of cerebral microdialysis, systemic cardiopulmonary parameters, and the administered drugs before and after the sedation switch were analyzed. RESULTS We included 19 patients with a median age of 61 years (range 46-78 years), 74% of whom presented with World Federation of Neurosurgical Societies grade 4 or 5 aSAH. We observed no significant changes in the mean ICP (9.3 ± 4.2 vs. 9.7 ± 4.2 mm Hg), PBrO2 (31.0 ± 13.2 vs. 32.2 ± 12.4 mm Hg), cerebral lactate (5.0 ± 2.2 vs. 5.0 ± 1.9 mmol/L), pyruvate (136.6 ± 55.9 vs. 134.1 ± 53.6 µmol/L), and lactate/pyruvate ratio (37.4 ± 8.7 vs. 39.8 ± 9.2) after the sedation switch to sevoflurane. We found a significant decrease in mean arterial pressure (MAP) (88.6 ± 7.6 vs. 86.3 ± 5.8 mm Hg) and CPP (78.8 ± 8.5 vs. 76.6 ± 6.6 mm Hg) after the initiation of sevoflurane, but the decrease was still within the physiological range requiring no additional hemodynamic support. CONCLUSIONS Sevoflurane appears to be a feasible alternative to intravenous sedation in patients with aSAH without intracranial hypertension, as our study did not show negative effects on ICP, cerebral oxygenation, or brain metabolism. Nevertheless, the risk of a decrease of MAP leading to a consecutive CPP decrease should be considered.
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Affiliation(s)
- Jan Leppert
- Department of Neurosurgery, University Hospital of Schleswig-Holstein, Campus Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany
| | - Jan Küchler
- Department of Neurosurgery, University Hospital of Schleswig-Holstein, Campus Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany
| | - Andreas Wagner
- Department of Neurosurgery, University Hospital of Schleswig-Holstein, Campus Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany
| | - Niclas Hinselmann
- Department of Neurosurgery, University Hospital of Schleswig-Holstein, Campus Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany
| | - Claudia Ditz
- Department of Neurosurgery, University Hospital of Schleswig-Holstein, Campus Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany.
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Mosneag IE, Flaherty SM, Wykes RC, Allan SM. Stroke and Translational Research - Review of Experimental Models with a Focus on Awake Ischaemic Induction and Anaesthesia. Neuroscience 2024; 550:89-101. [PMID: 38065289 DOI: 10.1016/j.neuroscience.2023.11.034] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 11/28/2023] [Accepted: 11/30/2023] [Indexed: 12/17/2023]
Abstract
Animal models are an indispensable tool in the study of ischaemic stroke with hundreds of drugs emerging from the preclinical pipeline. However, all of these drugs have failed to translate into successful treatments in the clinic. This has brought into focus the need to enhance preclinical studies to improve translation. The confounding effects of anaesthesia on preclinical stroke modelling has been raised as an important consideration. Various volatile and injectable anaesthetics are used in preclinical models during stroke induction and for outcome measurements such as imaging or electrophysiology. However, anaesthetics modulate several pathways essential in the pathophysiology of stroke in a dose and drug dependent manner. Most notably, anaesthesia has significant modulatory effects on cerebral blood flow, metabolism, spreading depolarizations, and neurovascular coupling. To minimise anaesthetic complications and improve translational relevance, awake stroke induction has been attempted in limited models. This review outlines anaesthetic strategies employed in preclinical ischaemic rodent models and their reported cerebral effects. Stroke related complications are also addressed with a focus on infarct volume, neurological deficits, and thrombolysis efficacy. We also summarise routinely used focal ischaemic stroke rodent models and discuss the attempts to induce some of these models in awake rodents.
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Affiliation(s)
- Ioana-Emilia Mosneag
- Division of Neuroscience, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom; Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science Centre, Northern Care Alliance NHS Foundation Trust, University of Manchester, Manchester, United Kingdom.
| | - Samuel M Flaherty
- Division of Neuroscience, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom; Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science Centre, Northern Care Alliance NHS Foundation Trust, University of Manchester, Manchester, United Kingdom
| | - Robert C Wykes
- Division of Neuroscience, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom; Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science Centre, Northern Care Alliance NHS Foundation Trust, University of Manchester, Manchester, United Kingdom; Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Stuart M Allan
- Division of Neuroscience, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom; Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science Centre, Northern Care Alliance NHS Foundation Trust, University of Manchester, Manchester, United Kingdom
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Ates N, Caglayan A, Balcikanli Z, Sertel E, Beker MC, Dilsiz P, Caglayan AB, Celik S, Dasdelen MF, Caglayan B, Yigitbasi T, Ozbek H, Doeppner TR, Hermann DM, Kilic E. Phosphorylation of PI3K/Akt at Thr308, but not MAPK kinase, mediates lithium-induced neuroprotection against cerebral ischemia in mice. Exp Neurol 2022; 351:113996. [PMID: 35122865 DOI: 10.1016/j.expneurol.2022.113996] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 12/31/2021] [Accepted: 01/27/2022] [Indexed: 11/30/2022]
Abstract
Lithium, in addition to its effect on acute and long-term bipolar disorder, is involved in neuroprotection after ischemic stroke. Yet, its mechanism of action is still poorly understood, which was only limited to its modulatory effect on GSK pathway. Therefore, we initially analyzed the dose-dependent effects of lithium on neurological deficits, infarct volume, brain edema and blood-brain barrier integrity, along with neuronal injury and survival in mice subjected to focal cerebral ischemia. Thereafter, we investigated the involvement of the PI3K/Akt and MEK signal transduction pathways and their components. Our observations revealed that 2 mmol/kg lithium significantly improved post-ischemic brain tissue survival. Although, 2 mmol/kg lithium had no negative effect on brain microcirculation, 5 and 20 mmol/kg lithium reduced brain perfusion. Furthermore, supratherapeutic dose of lithium in 20 mmol/kg lead to animal death. In addition, improvement of brain perfusion with L-arginine, did not change the effect of 5 mmol/kg lithium on brain injury. Additionally, post-stroke blood-brain barrier leakage, hemodynamic impairment and apoptosis have been reversed by lithium treatment. Interestingly, lithium-induced neuroprotection was associated with increased phosphorylation of Akt at Thr308 and suppressed GSK-3β phosphorylation at Ser9 residue. Lithium upregulated Erk-2 and downregulated JNK-2 phosphorylation. To distinguish whether neuroprotective effects of lithium are modulated by PI3K/Akt or MEK, we sequentially blocked these pathways and demonstrated that the neuroprotective activity of lithium persisted during MEK/ERK inhibition, whereas PI3K/Akt inhibition abolished neuroprotection. Collectively, we demonstrated lithium exerts its post-stroke neuroprotective activity via the PI3K/Akt pathway, specifically via Akt phosphorylation at Thr308, but not via MEK/ERK.
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Affiliation(s)
- Nilay Ates
- Istanbul Medipol University, Regenerative and Restorative Medical Research Center, Istanbul, Turkey; Istanbul Medipol University, Faculty of Medicine, Dept. of Pharmacology, Istanbul, Turkey
| | - Aysun Caglayan
- Istanbul Medipol University, Regenerative and Restorative Medical Research Center, Istanbul, Turkey; Istanbul Medipol University, Faculty of Medicine, Dept. of Physiology, Istanbul, Turkey
| | - Zeynep Balcikanli
- Istanbul Medipol University, Regenerative and Restorative Medical Research Center, Istanbul, Turkey; Istanbul Medipol University, Faculty of Medicine, Dept. of Physiology, Istanbul, Turkey
| | - Elif Sertel
- Istanbul Medipol University, Regenerative and Restorative Medical Research Center, Istanbul, Turkey; Istanbul Medipol University, Faculty of Medicine, Dept. of Physiology, Istanbul, Turkey
| | - Mustafa Caglar Beker
- Istanbul Medipol University, Regenerative and Restorative Medical Research Center, Istanbul, Turkey; Istanbul Medipol University, Faculty of Medicine, Dept. of Physiology, Istanbul, Turkey
| | - Pelin Dilsiz
- Istanbul Medipol University, Regenerative and Restorative Medical Research Center, Istanbul, Turkey; Istanbul Medipol University, Faculty of Medicine, Dept. of Pharmacology, Istanbul, Turkey
| | - Ahmet Burak Caglayan
- Istanbul Medipol University, Regenerative and Restorative Medical Research Center, Istanbul, Turkey; Istanbul Medipol University, Faculty of Medicine, Dept. of Physiology, Istanbul, Turkey
| | - Süleyman Celik
- Istanbul Medipol University, Regenerative and Restorative Medical Research Center, Istanbul, Turkey; Istanbul Medipol University, Faculty of Medicine, Dept. of Physiology, Istanbul, Turkey
| | - Muhammed Furkan Dasdelen
- Istanbul Medipol University, Regenerative and Restorative Medical Research Center, Istanbul, Turkey; Istanbul Medipol University, Faculty of Medicine, Dept. of Physiology, Istanbul, Turkey
| | - Berrak Caglayan
- Istanbul Medipol University, Regenerative and Restorative Medical Research Center, Istanbul, Turkey; Istanbul Medipol University, International School of Medicine, Dept. of Medical Biology, Istanbul, Turkey
| | - Türkan Yigitbasi
- Istanbul Medipol University, Faculty of Medicine, Dept. of Biochemistry, Istanbul, Turkey
| | - Hanefi Ozbek
- Istanbul Medipol University, Faculty of Medicine, Dept. of Pharmacology, Istanbul, Turkey
| | - Thorsten Roland Doeppner
- Istanbul Medipol University, Regenerative and Restorative Medical Research Center, Istanbul, Turkey; University Medical Center Göttingen, Department of Neurology, Göttingen, Germany
| | - Dirk Matthias Hermann
- University Hospital Essen, University of Duisburg-Essen, Department of Neurology, Essen, Germany
| | - Ertugrul Kilic
- Istanbul Medipol University, Regenerative and Restorative Medical Research Center, Istanbul, Turkey; Istanbul Medipol University, Faculty of Medicine, Dept. of Physiology, Istanbul, Turkey.
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Sullender CT, Richards LM, He F, Luan L, Dunn AK. Dynamics of isoflurane-induced vasodilation and blood flow of cerebral vasculature revealed by multi-exposure speckle imaging. J Neurosci Methods 2022; 366:109434. [PMID: 34863840 PMCID: PMC9258779 DOI: 10.1016/j.jneumeth.2021.109434] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 11/12/2021] [Accepted: 11/29/2021] [Indexed: 10/19/2022]
Abstract
BACKGROUND Anesthetized animal models are used extensively during neurophysiological and behavioral studies despite systemic effects from anesthesia that undermine both accurate interpretation and translation to awake human physiology. The majority of work examining the impact of anesthesia on cerebral blood flow (CBF) has been restricted to before and after measurements with limited spatial resolution. NEW METHOD We used multi-exposure speckle imaging (MESI), an advanced form of laser speckle contrast imaging (LSCI), to characterize the dynamics of isoflurane anesthesia induction on cerebral vasculature and blood flow in the mouse brain. RESULTS The large anatomical changes caused by isoflurane are depicted with wide-field imagery and video highlighting the induction of general anesthesia. Within minutes of exposure, both vessel diameter and blood flow increased drastically compared to the awake state and remained elevated for the duration of imaging. An examination of the dynamics of anesthesia induction reveals that blood flow increased faster in arteries than in veins or parenchyma regions. COMPARISON WITH EXISTING METHODS MESI offers robust hemodynamic measurements across large fields-of-view and high temporal resolutions sufficient for continuous visualization of cerebrovascular events featuring major changes in blood flow. CONCLUSION The large alterations caused by isoflurane anesthesia to the cortical vasculature and CBF are readily characterized using MESI. These changes are unrepresentative of normal physiology and provide further evidence that neuroscience experiments would benefit from transitioning to un-anesthetized awake animal models.
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Affiliation(s)
- Colin T Sullender
- Department of Biomedical Engineering, University of Texas at Austin, 107 W. Dean Keeton Street Stop C0800, Austin, TX 78712, United States
| | - Lisa M Richards
- Department of Biomedical Engineering, University of Texas at Austin, 107 W. Dean Keeton Street Stop C0800, Austin, TX 78712, United States
| | - Fei He
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, United States
| | - Lan Luan
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, United States; Department of Bioengineering, Rice University, 6100 Main Street, Houston, TX 77005, United States
| | - Andrew K Dunn
- Department of Biomedical Engineering, University of Texas at Austin, 107 W. Dean Keeton Street Stop C0800, Austin, TX 78712, United States.
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Sheng R, Chen JL, Qin ZH. Cerebral conditioning: Mechanisms and potential clinical implications. BRAIN HEMORRHAGES 2021. [DOI: 10.1016/j.hest.2021.08.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
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Distinctive effect of anesthetics on the effect of limb remote ischemic postconditioning following ischemic stroke. PLoS One 2020; 15:e0227624. [PMID: 31945776 PMCID: PMC6964983 DOI: 10.1371/journal.pone.0227624] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 12/24/2019] [Indexed: 12/17/2022] Open
Abstract
Limb remote ischemic postconditioning (LRIP) has been reported as an effective method to reduce the induced experimental stroke damage after ischemic reperfusion (IR) injury. Studies suggest that anesthetics used during induction of ischemic stroke can reduce IR injury, which could affect the actual mechanisms of neuroprotection by LRIP. This study focuses on the comparative effects of anesthetics such as isoflurane and ketamine-xylazine on ischemic injury when used during LRIP. Adult C57BL/6 mice were anesthetized by isoflurane or halothane, and transient middle cerebral artery occlusion (MCAO) was induced through insertion of the filament. Under isoflurane or ketamine-xylazine anesthesia, LRIP was performed after 90 min of reperfusion by carrying out three cycles of 5 min ischemia/5 min reperfusion of the bilateral hind limbs for one session per day for a total of 3 days. Results showed that the use of different anesthetics—isoflurane or ketamine-xylazine—during LRIP had no effects on body weight. However, LRIP was able to improve neurological function as observed by the neurological deficit score in ischemic mice. Interestingly, the neurological deficit in the group where ketamine-xylazine was used was better than the group where isoflurane was used during LRIP. Furthermore, the LRIP was able to prolong the period of the ischemic mice on the rotarod and this effect was more significant in the groups where ketamine-xylazine was used during LRIP. Moreover, LRIP significantly attenuated the infarction volume; however, this effect was independent of the anesthetic used during LRIP. From these results, we conclude that ischemic mice that were subjected to LRIP under ketamine-xylazine anesthesia had better neurological deficit outcomes after stroke.
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Uddin O, Studlack PE, Parihar S, Keledjian K, Cruz A, Farooq T, Shin N, Gerzanich V, Simard JM, Keller A. Chronic pain after blast-induced traumatic brain injury in awake rats. NEUROBIOLOGY OF PAIN (CAMBRIDGE, MASS.) 2019; 6:100030. [PMID: 31223145 PMCID: PMC6565615 DOI: 10.1016/j.ynpai.2019.100030] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 02/14/2019] [Accepted: 04/01/2019] [Indexed: 12/14/2022]
Abstract
Explosive blast-induced traumatic brain injury (blast-TBI) in military personnel is a leading cause of injury and persistent neurological abnormalities, including chronic pain. We previously demonstrated that chronic pain after spinal cord injury results from central sensitization in the posterior thalamus (PO). The presence of persistent headaches and back pain in veterans with blast-TBI suggests a similar involvement of thalamic sensitization. Here, we tested the hypothesis that pain after blast-TBI is associated with abnormal increases in activity of neurons in PO thalamus. We developed a novel model with two unique features: (1) blast-TBI was performed in awake, un-anesthetized rats, to simulate the human experience and to eliminate confounds of anesthesia and surgery inherent in other models; (2) only the cranium, rather than the entire body, was exposed to a collimated blast wave, with the blast wave striking the posterior cranium in the region of the occipital crest and foramen magnum. Three weeks after blast-TBI, rats developed persistent, ongoing spontaneous pain. Contrary to our hypothesis, we found no significant differences in the activity of PO neurons, or of neurons in the spinal trigeminal nucleus. There were also no significant changes in gliosis in either of these structures. This novel model will allow future studies on the pathophysiology of chronic pain after blast-TBI.
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Affiliation(s)
- Olivia Uddin
- Department of Anatomy and Neurobiology and Program in Neuroscience, University of Maryland School of Medicine, 20 Penn St, HSF-II S251, Baltimore, MD, USA
| | - Paige E. Studlack
- Department of Anatomy and Neurobiology and Program in Neuroscience, University of Maryland School of Medicine, 20 Penn St, HSF-II S251, Baltimore, MD, USA
| | - Saitu Parihar
- Department of Anatomy and Neurobiology and Program in Neuroscience, University of Maryland School of Medicine, 20 Penn St, HSF-II S251, Baltimore, MD, USA
| | - Kaspar Keledjian
- Department of Neurosurgery, University of Maryland School of Medicine, 10 S Pine St, MSTF 634B, Baltimore, MD, USA
| | - Alexis Cruz
- Department of Anatomy and Neurobiology and Program in Neuroscience, University of Maryland School of Medicine, 20 Penn St, HSF-II S251, Baltimore, MD, USA
| | - Tayyiaba Farooq
- Department of Anatomy and Neurobiology and Program in Neuroscience, University of Maryland School of Medicine, 20 Penn St, HSF-II S251, Baltimore, MD, USA
| | - Naomi Shin
- Department of Anatomy and Neurobiology and Program in Neuroscience, University of Maryland School of Medicine, 20 Penn St, HSF-II S251, Baltimore, MD, USA
| | - Volodymyr Gerzanich
- Department of Neurosurgery, University of Maryland School of Medicine, 10 S Pine St, MSTF 634B, Baltimore, MD, USA
| | - J. Marc Simard
- Department of Neurosurgery, University of Maryland School of Medicine, 10 S Pine St, MSTF 634B, Baltimore, MD, USA
- Department of Pathology, University of Maryland School of Medicine, 10 S Pine St, MSTF, Room 634B, Baltimore, MD, USA
- Department of Physiology, University of Maryland School of Medicine, 10 S Pine St, MSTF, Room 634B, Baltimore, MD, USA
| | - Asaf Keller
- Department of Anatomy and Neurobiology and Program in Neuroscience, University of Maryland School of Medicine, 20 Penn St, HSF-II S251, Baltimore, MD, USA
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Isoflurane Preconditioning Attenuates Brain Injury Induced by Electromagnetic Pulse via the TLR4/NF κB Signaling Pathway. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:9653494. [PMID: 30723536 PMCID: PMC6339739 DOI: 10.1155/2019/9653494] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 10/15/2018] [Accepted: 10/24/2018] [Indexed: 12/27/2022]
Abstract
Electromagnetic pulse (EMP) is a unique type of electromagnetic radiation, and EMP exposure causes a series of biological effects. The nervous system is sensitive to EMP. We studied the neuroprotective effects of isoflurane preconditioning against EMP exposure and used hematoxylin-eosin staining (HE) to observe the effects of electromagnetic pulse and isoflurane preconditioning on neurons. Inflammatory cytokines were detected by enzyme-linked immunosorbent assay (ELISA). Western blotting was used to detect the expression of caspase-3, CD11b, TLR4, and NFκBp65. We found that after EMP exposure, the number of abnormal neurons had increased, and the expression of caspase-3, CD11b, TLR4, and NFκBp65 had also increased. Isoflurane preconditioning can reverse the above phenomenon. Moreover, we found that isoflurane preconditioning can reduce neuronal apoptosis and improve cognitive impairment induced by EMP. These findings indicate that isoflurane preconditioning can protect neurons in the cerebral cortex from EMP exposure, alleviate the inflammatory reaction and cell apoptosis, and improve cognitive impairment induced by EMP. These effects may occur through the downregulation of the TLR4/NFκB signaling pathway and the inhibition of microglial activation.
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TASK channels contribute to neuroprotective action of inhalational anesthetics. Sci Rep 2017; 7:44203. [PMID: 28276488 PMCID: PMC5343576 DOI: 10.1038/srep44203] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 02/06/2017] [Indexed: 01/13/2023] Open
Abstract
Postconditioning with inhalational anesthetics can reduce ischemia-reperfusion brain injury, although the cellular mechanisms for this effect have not been determined. The current study was designed to test if TASK channels contribute to their neuroprotective actions. Whole cell recordings were used to examine effects of volatile anesthetic on TASK currents in cortical neurons and to verify loss of anesthetic-activated TASK currents from TASK−/− mice. A transient middle cerebral artery occlusion (tMCAO) model was used to establish brain ischemia-reperfusion injury. Quantitative RT-PCR analysis revealed that TASK mRNA was reduced by >90% in cortex and hippocampus of TASK−/− mice. The TASK−/− mice showed a much larger region of infarction than C57BL/6 J mice after tMCAO challenge. Isoflurane or sevoflurane administered after the ischemic insult reduced brain infarct percentage and neurological deficit scores in C57BL/6 J mice, these effect were reduced in TASK−/− mice. Whole cell recordings revealed that the isoflurane-activated background potassium current observed in cortical pyramidal neurons from wild type mice was conspicuously reduced in TASK−/− mice. Our studies demonstrate that TASK channels can limit ischemia-reperfusion damage in the cortex, and postconditioning with volatile anesthetics provides neuroprotective actions that depend, in part, on activation of TASK currents in cortical neurons.
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Bayerl SH, Nieminen-Kelhä M, Broggini T, Vajkoczy P, Prinz V. Lateral Chronic Cranial Window Preparation Enables In Vivo Observation Following Distal Middle Cerebral Artery Occlusion in Mice. J Vis Exp 2016. [PMID: 28060307 DOI: 10.3791/54701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Focal cerebral ischemia (i.e., ischemic stroke) may cause major brain injury, leading to a severe loss of neuronal function and consequently to a host of motor and cognitive disabilities. Its high prevalence poses a serious health burden, as stroke is among the principal causes of long-term disability and death worldwide1. Recovery of neuronal function is, in most cases, only partial. So far, treatment options are very limited, in particular due to the narrow time window for thrombolysis2,3. Determining methods to accelerate recovery from stroke remains a prime medical goal; however, this has been hampered by insufficient mechanistic insights into the recovery process. Experimental stroke researchers frequently employ rodent models of focal cerebral ischemia. Beyond the acute phase, stroke research is increasingly focused on the sub-acute and chronic phase following cerebral ischemia. Most stroke researchers apply permanent or transient occlusion of the MCA in mice or rats. In patients, occlusions of the MCA are among the most frequent causes of ischemic stroke4. Besides proximal occlusion of the MCA using the filament model, surgical occlusion of the distal MCA is probably the most frequently used model in experimental stroke research5. Occlusion of a distal (to the branching of the lenticulo-striate arteries) MCA branch typically spares the striatum and primarily affects the neocortex. Vessel occlusion can be permanent or transient. High reproducibility of lesion volume and very low mortality rates with respect to the long-term outcome are the main advantages of this model. Here, we demonstrate how to perform a chronic cranial window (CW) preparation lateral to the sagittal sinus, and afterwards how to surgically induce a distal stroke underneath the window using a craniotomy approach. This approach can be applied for sequential imaging of acute and chronic changes following ischemia via epi-illuminating, confocal laser scanning, and two-photon intravital microscopy.
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Affiliation(s)
- Simon H Bayerl
- Department of Neurosurgery and Center for Stroke-research Berlin (CSB), Charité-Universitätsmedizin
| | - Melina Nieminen-Kelhä
- Department of Neurosurgery and Center for Stroke-research Berlin (CSB), Charité-Universitätsmedizin
| | | | - Peter Vajkoczy
- Department of Neurosurgery and Center for Stroke-research Berlin (CSB), Charité-Universitätsmedizin
| | - Vincent Prinz
- Department of Neurosurgery and Center for Stroke-research Berlin (CSB), Charité-Universitätsmedizin;
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Constantinides C, Murphy K. Molecular and Integrative Physiological Effects of Isoflurane Anesthesia: The Paradigm of Cardiovascular Studies in Rodents using Magnetic Resonance Imaging. Front Cardiovasc Med 2016; 3:23. [PMID: 27525256 PMCID: PMC4965459 DOI: 10.3389/fcvm.2016.00023] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 07/04/2016] [Indexed: 12/19/2022] Open
Abstract
To-this-date, the exact molecular, cellular, and integrative physiological mechanisms of anesthesia remain largely unknown. Published evidence indicates that anesthetic effects are multifocal and occur in a time-dependent and coordinated manner, mediated via central, local, and peripheral pathways. Their effects can be modulated by a range of variables, and their elicited end-effect on the integrative physiological response is highly variable. This review summarizes the major cellular and molecular sites of anesthetic action with a focus on the paradigm of isoflurane (ISO) - the most commonly used anesthetic nowadays - and its use in prolonged in vivo rodent studies using imaging modalities, such as magnetic resonance imaging (MRI). It also presents established evidence for normal ranges of global and regional physiological cardiac function under ISO, proposes optimal, practical methodologies relevant to the use of anesthetic protocols for MRI and outlines the beneficial effects of nitrous oxide supplementation.
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Affiliation(s)
- Christakis Constantinides
- Chi Biomedical Ltd., Nicosia, Cyprus; Division of Cardiovascular Medicine, University of Oxford, Oxford, UK
| | - Kathy Murphy
- Division of Biomedical Sciences, University of Oxford , Oxford , UK
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Abstract
Despite more than 30 years of aggressive neuroprotective research by many investigators, neuropsychological deficit after cardiac surgery remains an important cause of postoperative morbidity. Although the neurological outcome is a result of a multifactorial etiology, many physicians world-wide have recognized the importance of this problem, and extensive efforts have been made in attempting to minimize the incidence of neurological and neurocognitive dysfunction. Pharmacological intervention is one of the important potential methods of neuroprotection during cardiac surgery. In vitro studies have identified drugs that are effective protectants against focal cerebral ischemia, hemorrhage, and global ischemia. However, at present there is no solid agreement on the need for prophylactic neuroprotectants in cardiac surgery. Researchers and clinicians must become more cognizant of the pitfalls and paradoxes that have arisen in attempting to translate the results of animal studies into clinical trial, with regard to neuroprotective therapy during cardiac surgery. There is an extensive need for new pharmacological approaches directed at reducing neurologic and neurocognitive injury during cardiac surgery. This article reviews past and present neuroprotective efforts and interventions during cardiac surgery.
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Affiliation(s)
- Yuji Kadoi
- Department of Anesthesiology, Gunma University, Graduate School of Medicine, Gunma, Japan.
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Poinsatte K, Selvaraj UM, Ortega SB, Plautz EJ, Kong X, Gidday JM, Stowe AM. Quantification of neurovascular protection following repetitive hypoxic preconditioning and transient middle cerebral artery occlusion in mice. J Vis Exp 2015:e52675. [PMID: 25993394 DOI: 10.3791/52675] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Experimental animal models of stroke are invaluable tools for understanding stroke pathology and developing more effective treatment strategies. A 2 week protocol for repetitive hypoxic preconditioning (RHP) induces long-term protection against central nervous system (CNS) injury in a mouse model of focal ischemic stroke. RHP consists of 9 stochastic exposures to hypoxia that vary in both duration (2 or 4 hr) and intensity (8% and 11% O2). RHP reduces infarct volumes, blood-brain barrier (BBB) disruption, and the post-stroke inflammatory response for weeks following the last exposure to hypoxia, suggesting a long-term induction of an endogenous CNS-protective phenotype. The methodology for the dual quantification of infarct volume and BBB disruption is effective in assessing neurovascular protection in mice with RHP or other putative neuroprotectants. Adult male Swiss Webster mice were preconditioned by RHP or duration-equivalent exposures to 21% O2 (i.e. room air). A 60 min transient middle cerebral artery occlusion (tMCAo) was induced 2 weeks following the last hypoxic exposure. Both the occlusion and reperfusion were confirmed by transcranial laser Doppler flowmetry. Twenty-two hr after reperfusion, Evans Blue (EB) was intravenously administered through a tail vein injection. 2 hr later, animals were sacrificed by isoflurane overdose and brain sections were stained with 2,3,5- triphenyltetrazolium chloride (TTC). Infarcts volumes were then quantified. Next, EB was extracted from the tissue over 48 hr to determine BBB disruption after tMCAo. In summary, RHP is a simple protocol that can be replicated, with minimal cost, to induce long-term endogenous neurovascular protection from stroke injury in mice, with the translational potential for other CNS-based and systemic pro-inflammatory disease states.
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Affiliation(s)
- Katherine Poinsatte
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center
| | - Uma Maheswari Selvaraj
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center
| | - Sterling B Ortega
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center
| | - Erik J Plautz
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center
| | - Xiangmei Kong
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center
| | - Jeffrey M Gidday
- Department of Neurological Surgery, Washington University School of Medicine
| | - Ann M Stowe
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center;
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Bai J, Lyden PD. Revisiting Cerebral Postischemic Reperfusion Injury: New Insights in Understanding Reperfusion Failure, Hemorrhage, and Edema. Int J Stroke 2015; 10:143-52. [DOI: 10.1111/ijs.12434] [Citation(s) in RCA: 151] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 11/14/2014] [Indexed: 01/11/2023]
Abstract
Cerebral postischemic reperfusion injury is defined as deterioration of ischemic brain tissue that parallels and antagonizes the benefits of restoring cerebral circulation after therapeutic thrombolysis for acute ischemic stroke. To understand the paradox of injury caused by treatment, we first emphasize the phenomenon in which recanalization of an occluded artery does not lead to tissue reperfusion. Additionally, no-reflow after recanalization may be due to injury of the neurovascular unit, distal microthrombosis, or both, and certainly worsens outcome. We examine the mechanism of molecular and sub-cellular damage in the neurovascular unit, notably oxidative stress, mitochondrial dysfunction, and apoptosis. At the level of the neurovascular unit, which mediates crosstalk between the damaged brain and systemic responses in blood, we summarize emerging evidence demonstrating that individual cell components play unique and cumulative roles that lead to damage of the blood–brain barrier and neurons. Furthermore, we review the latest developments in establishing a link between the immune system and microvascular dysfunction during ischemic reperfusion. Progress in assessing reperfusion injury has also been made, and we review imaging studies using various magnetic resonance imaging modalities. Lastly, we explore potential treatment approaches, including ischemic preconditioning, postconditioning, pharmacologic agents, and hypothermia.
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Affiliation(s)
- Jilin Bai
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Patrick D. Lyden
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
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15
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Yu CL, Zhou H, Chai AP, Yang YX, Mao RR, Xu L. Whole-scale neurobehavioral assessments of photothrombotic ischemia in freely moving mice. J Neurosci Methods 2014; 239:100-7. [PMID: 25455338 DOI: 10.1016/j.jneumeth.2014.10.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 10/08/2014] [Accepted: 10/09/2014] [Indexed: 01/14/2023]
Abstract
BACKGROUND Neurobehavioral assessments have been considered as an essential component of preclinical research in ischemic stroke. However, real-time neurobehavioral evaluation is seldom applied during ischemia induction as it is usually accompanied with anesthesia. NEW METHOD We induced photothrombosis in freely moving mice after one-week recovery from cannula implantation surgeries. After rose bengal (RB) injection (100 mg/kg, i.p.), photothrombosis was induced in freely moving mice by 473 nm laser irradiation through the cannulas implanted into unilateral primary motor cortex beforehand. Mice received nimodipine (15 mg/kg, i.p.), a widely used anti-ischemic agent, or vehicle before irradiation. Motor coordination and equilibrium were evaluated by rotarod and rung walk tests throughout the whole process of ischemia. Endurance capacity was assessed by treadmill at 1 day and 7 days after irradiation. Mice were decapitated at different time points post irradiation for TTC (2,3,5-triphenyltetrazolium chloride) staining. RESULTS Consistent with the results of TTC staining, motor deficits firstly occurred at 15-min post irradiation and aggravated 1-day later, while the capacity improved 3-days later and partially recovered 7-days post irradiation. And, the recovery process was accelerated by nimodipine application. COMPARISON WITH EXISTING METHODS This method established a precise linkage between focal brain ischemia development and neurobehavioral deficits throughout a full scale of photothrombosis, which avoided the confounding factors of anesthetics and surgeries on neurobehavioral assessments, as infarct was induced in freely moving mice. CONCLUSIONS This method with high temporal and spatial resolution will be an optimal model for neurobehavioral evaluation in preclinical anti-ischemic drug screening.
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Affiliation(s)
- Cheng-Long Yu
- School of Life Sciences, University of Science and Technology of China, Hefei 230027, China; Key Laboratory of Animal Models and Human Disease Mechanisms, and KIZ/CUHK Joint Laboratory of Bioresources and Molecular Research in Common Disease, and Laboratory of Learning and Memory, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Heng Zhou
- School of Life Sciences, University of Science and Technology of China, Hefei 230027, China; Key Laboratory of Animal Models and Human Disease Mechanisms, and KIZ/CUHK Joint Laboratory of Bioresources and Molecular Research in Common Disease, and Laboratory of Learning and Memory, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - An-Ping Chai
- Key Laboratory of Animal Models and Human Disease Mechanisms, and KIZ/CUHK Joint Laboratory of Bioresources and Molecular Research in Common Disease, and Laboratory of Learning and Memory, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Yue-Xiong Yang
- Key Laboratory of Animal Models and Human Disease Mechanisms, and KIZ/CUHK Joint Laboratory of Bioresources and Molecular Research in Common Disease, and Laboratory of Learning and Memory, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Rong-Rong Mao
- Key Laboratory of Animal Models and Human Disease Mechanisms, and KIZ/CUHK Joint Laboratory of Bioresources and Molecular Research in Common Disease, and Laboratory of Learning and Memory, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China.
| | - Lin Xu
- School of Life Sciences, University of Science and Technology of China, Hefei 230027, China; Key Laboratory of Animal Models and Human Disease Mechanisms, and KIZ/CUHK Joint Laboratory of Bioresources and Molecular Research in Common Disease, and Laboratory of Learning and Memory, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China.
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16
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Seto A, Taylor S, Trudeau D, Swan I, Leung J, Reeson P, Delaney KR, Brown CE. Induction of ischemic stroke in awake freely moving mice reveals that isoflurane anesthesia can mask the benefits of a neuroprotection therapy. FRONTIERS IN NEUROENERGETICS 2014; 6:1. [PMID: 24765075 PMCID: PMC3982055 DOI: 10.3389/fnene.2014.00001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 03/15/2014] [Indexed: 11/13/2022]
Abstract
Anesthetics such as isoflurane are commonly used to sedate experimental animals during the induction of stroke. Since these agents are known to modulate synaptic excitability, inflammation and blood flow, they could hinder the development and discovery of new neuroprotection therapies. To address this issue, we developed a protocol for inducing photothrombotic occlusion of cerebral vessels in fully conscious mice and tested two potential neuroprotectant drugs (a GluN2B or α4β2 nicotinic receptor antagonist). Our data show in vehicle treated mice that just 20 min of exposure to isoflurane during stroke induction can significantly reduce ischemic cortical damage relative to mice that were awake during stroke. When comparing potential stroke therapies, none provided any level of neuroprotection if the stroke was induced with anesthesia. However, if mice were fully conscious during stroke, the α4β2 nicotinic receptor antagonist reduced ischemic damage by 23% relative to vehicle treated controls, whereas the GluN2B antagonist had no significant effect. These results suggest that isoflurane anesthesia can occlude the benefits of certain stroke treatments and warrant caution when using anesthetics for pre-clinical testing of neuroprotective agents.
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Affiliation(s)
- Angela Seto
- Division of Medical Sciences, University of Victoria Victoria, BC, Canada ; Department of Biology, University of Victoria Victoria, BC, Canada
| | - Stephanie Taylor
- Division of Medical Sciences, University of Victoria Victoria, BC, Canada
| | - Dustin Trudeau
- Division of Medical Sciences, University of Victoria Victoria, BC, Canada
| | - Ian Swan
- Department of Biology, University of Victoria Victoria, BC, Canada
| | - Jay Leung
- Department of Biology, University of Victoria Victoria, BC, Canada
| | - Patrick Reeson
- Division of Medical Sciences, University of Victoria Victoria, BC, Canada
| | - Kerry R Delaney
- Department of Biology, University of Victoria Victoria, BC, Canada
| | - Craig E Brown
- Division of Medical Sciences, University of Victoria Victoria, BC, Canada ; Department of Biology, University of Victoria Victoria, BC, Canada ; Department of Psychiatry, University of British Columbia Vancouver, BC, Canada
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Abstract
A transient, ischemia-resistant phenotype known as "ischemic tolerance" can be established in brain in a rapid or delayed fashion by a preceding noninjurious "preconditioning" stimulus. Initial preclinical studies of this phenomenon relied primarily on brief periods of ischemia or hypoxia as preconditioning stimuli, but it was later realized that many other stressors, including pharmacologic ones, are also effective. This review highlights the surprisingly wide variety of drugs now known to promote ischemic tolerance, documented and to some extent mechanistically characterized in preclinical animal models of stroke. Although considerably more experimentation is needed to thoroughly validate the ability of any currently identified preconditioning agent to protect ischemic brain, the fact that some of these drugs are already clinically approved for other indications implies that the growing enthusiasm for translational success in the field of pharmacologic preconditioning may be well justified.
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18
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Speetzen LJ, Endres M, Kunz A. Bilateral common carotid artery occlusion as an adequate preconditioning stimulus to induce early ischemic tolerance to focal cerebral ischemia. J Vis Exp 2013:e4387. [PMID: 23685461 DOI: 10.3791/4387] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
There is accumulating evidence, that ischemic preconditioning - a non-damaging ischemic challenge to the brain - confers a transient protection to a subsequent damaging ischemic insult. We have established bilateral common carotid artery occlusion as a preconditioning stimulus to induce early ischemic tolerance to transient focal cerebral ischemia in C57Bl6/J mice. In this video, we will demonstrate the methodology used for this study.
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Affiliation(s)
- Lukas Julius Speetzen
- Department of Neurology, Center for Stroke Research Berlin, Charité - Universitätsmedizin Berlin, Germany
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19
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Tang Q, Han R, Xiao H, Shi L, Shen J, Lun Q, Li J. Role of suture diameter and vessel insertion position in the establishment of the middle cerebral artery occlusion rat model. Exp Ther Med 2013; 5:1603-1608. [PMID: 23837039 PMCID: PMC3702724 DOI: 10.3892/etm.2013.1046] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 01/21/2013] [Indexed: 11/12/2022] Open
Abstract
The aim of the present study was to explore the role of suture diameter and vessel insertion position in the preparation of the middle cerebral artery occlusion (MCAO) rat model. A total of 84 Sprague-Dawley rats (weighing 250–300 g) were randomly divided to three groups: group A (type 1.0, suture diameter 0.16–0.17 mm and tip 0.21–0.22 mm); group B (type 2.0; suture diameter, 0.22–0.23 mm; tip, 0.27–0.28 mm); and group C (type 3.0; suture diameter, 0.28–0.29 mm; and tip, 0.33–0.34 mm). The animals in each group were then subdivided into two subgroups, one of which received a nylon line inserted through the external carotid artery (ECA insertion), while the other received the nylon line through the common carotid artery (CCA insertion) subsequent to a middle or lateral neck incision. The neurological deficit score was evaluated at 4, 8, 24, 48 and 72 h post-surgery. The ischemic brain tissue was stained by 2,3,5-triphenyltetrazolium chloride (TTC) to evaluate the extent of the infarct volume. The cerebral edema rate, cerebral infarction volume rate, relative standard deviation (RSD) of the cerebral infarction rate and the success rate were also assessed. The rectal temperature, PaO2, PaCO2, pH, blood pressure and blood glucose levels were controlled and did not vary between the group types. The results suggested that suture diameter and insertion route affected the infarct volume and success rate in the establishment of the suture MCAO rat model. Furthermore, the MCAO model with a 0.22–0.23 mm diameter suture and CCA insertion route provided the highest success rate in the SD rats.
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Affiliation(s)
- Qiqiang Tang
- Department of Neurology, Affiliated Provincial Hospital of Anhui Medical University; Hefei, Anhui 230032, P.R. China
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20
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Lee HJ, Suh JK, Song HH, Jeong MA, Yeom JH, Kim DW. Antioxidant effects of methylprednisolone and hydrocortisone on the impairment of endothelium dependent relaxation induced by reactive oxygen species in rabbit abdominal aorta. Korean J Anesthesiol 2013; 64:54-60. [PMID: 23372887 PMCID: PMC3558650 DOI: 10.4097/kjae.2013.64.1.54] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 10/12/2012] [Accepted: 10/13/2012] [Indexed: 12/03/2022] Open
Abstract
Background The reperfusion following ischemia produces reactive oxygen species (ROS). We studied the influences of methylprednisolone (MPD) and hydrocortisone (CRT) on ROS effects using the endothelium of rabbit abdominal aorta. Methods Isolated rabbit aortic rings were suspended in an organ bath filled with Krebs-Henseleit (K-H) solution. After precontraction with norepinephrine, changes in arterial tension were recorded following the cumulative administration of acetylcholine (ACh). The percentages of ACh-induced relaxation of aortic rings before and after exposure to ROS, generated by electrolysis of K-H solution, were used as the control and experimental values, respectively. The aortic rings were pretreated with MPD or CRT at the same concentrations, and the effects of these agents were compared with the effects of ROS scavenger inhibitors: superoxide dismutase inhibitor, diethylthiocarbamate (DETCA), and the catalase inhibitor, 3-amino-1,2,4-triazole (3AT). Results Both MPD and CRT maintained endothelium-dependent relaxation induced by ACh in a dose-related manner in spite of ROS attack. The restored ACh-induced relaxation of MPD and CRT group was not attenuated by pretreatment of 3AT and DETCA. Conclusions MPD and CRT preserve the endothelium-dependent vasorelaxation against the attack of ROS, in a dose-related manner. Endothelial protection mechanisms of MPD and CRT may be not associated with hydrogen peroxide and superoxide scavenging.
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Affiliation(s)
- Hee Jong Lee
- Department of Anesthesiology and Pain Medicine, Hanyang University Hospital, Seoul, Korea
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21
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Bösel J, Purrucker JC, Nowak F, Renzland J, Schiller P, Pérez EB, Poli S, Brunn B, Hacke W, Steiner T. Volatile isoflurane sedation in cerebrovascular intensive care patients using AnaConDa(®): effects on cerebral oxygenation, circulation, and pressure. Intensive Care Med 2012; 38:1955-64. [PMID: 23096426 DOI: 10.1007/s00134-012-2708-8] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Accepted: 08/12/2012] [Indexed: 12/11/2022]
Abstract
PURPOSE The anesthetic-conserving device AnaConDa(®), a miniature vaporizer, allows volatile sedation in the intensive care unit (ICU). We investigated the effects of isoflurane sedation on cerebral and systemic physiology parameters in neuromonitored ICU stroke patients. METHODS Included in the study were 19 consecutive ventilated patients with intracerebral hemorrhage (12), subarachnoid hemorrhage (4), and ischemic stroke (3) who were switched from intravenous propofol or midazolam to inhalative isoflurane sedation for an average of 3.5 days. During the sedation transition, the following parameters were assessed: mean arterial pressure (MAP), intracranial pressure (ICP), cerebral perfusion pressure (CPP), middle cerebral artery mean flow velocity (MFV) and cerebral fractional tissue oxygen extraction (FTOE), as well as systemic cardiopulmonary parameters and administered drugs. RESULTS After the first hour, mean ICP showed an increase of 2.1 mmHg that was not clinically relevant. Likewise, MFV did not change. MAP and CPP, however, decreased by 6.5 and 6.3 mmHg, respectively. FTOE was reduced slightly from 0.24 to 0.21 (p = 0.03). Over an observation period of 12 h, ICP remained stable, while MAP and thus CPP showed distinct decreases (CPP: -10 mmHg at 6 h, p < 0.001; -7.5 mmHg at 12 h, p = 0.005, when compared to preswitch levels) despite a 1.5-fold increase in vasopressor administration. CONCLUSIONS We suggest that that it is possible to reach sufficient sedation levels in cerebrovascular ICU patients by applying volatile isoflurane long-term without a relevant increase in ICP, if baseline ICP values are low or only moderately elevated. However, caution should be exercised in view of isoflurane's decreasing effect on MAP and CPP. Multimodal neuromonitoring is strongly recommended when applying this off-label sedation method.
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Affiliation(s)
- Julian Bösel
- Department of Neurology, University of Heidelberg, Heidelberg, Germany.
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22
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Dalrymple SL, Becker RE, Zhou H, DeWeese TL, Isaacs JT. Tasquinimod prevents the angiogenic rebound induced by fractionated radiation resulting in an enhanced therapeutic response of prostate cancer xenografts. Prostate 2012; 72:638-48. [PMID: 21837778 PMCID: PMC4086682 DOI: 10.1002/pros.21467] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Accepted: 07/05/2011] [Indexed: 01/04/2023]
Abstract
BACKGROUND Tasquinimod is a novel inhibitor of tumor angiogenesis which enhances therapeutic efficacy when combined with androgen ablation and/or taxane-based chemotherapies in pre-clinical prostate cancer models. It has entered registration Phase III evaluation for the treatment of castration resistant prostate cancer. Since tasquinimod suppresses the angiogenic switch induced by tumor hypoxia as prostate cancers outgrow their blood supply, this raises the issue of whether tasquinimod also suppresses the angiogenic rebound induced by fractionated radiation thereby enhancing therapeutic response to fractionated radiation. METHODS Human endothelial and prostate cancer cells in culture and human prostate cancer xenografts growing in castrated male nude mice were evaluated for their response to radiation alone and in combination with tasquinimod. RESULTS At clinically relevant drug levels, tasquinimod significantly (P < 0.05) enhances anti-cancer efficacy of fractionated radiation with optimal timing for initiating daily tasquinimod treatment being after completion of the fractionated radiation. CONCLUSIONS Based upon cell culture studies and tumor tissue oxygenation (i.e., pO(2)), tumor vascular volume, and tumor blood vessel density measurements, the mechanism for such enhancement and optimal timing involves tasquinimod's ability to prevent the angiogenic rebound induced by fractionated radiation.
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Affiliation(s)
- Susan L Dalrymple
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
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Meybohm P, Gruenewald M, Albrecht M, Müller C, Zitta K, Foesel N, Maracke M, Tacke S, Schrezenmeir J, Scholz J, Bein B. Pharmacological postconditioning with sevoflurane after cardiopulmonary resuscitation reduces myocardial dysfunction. Crit Care 2011; 15:R241. [PMID: 22011328 PMCID: PMC3334792 DOI: 10.1186/cc10496] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 09/07/2011] [Accepted: 10/19/2011] [Indexed: 11/22/2022] Open
Abstract
Introduction In this study, we sought to examine whether pharmacological postconditioning with sevoflurane (SEVO) is neuro- and cardioprotective in a pig model of cardiopulmonary resuscitation. Methods Twenty-two pigs were subjected to cardiac arrest. After 8 minutes of ventricular fibrillation and 2 minutes of basic life support, advanced cardiac life support was started. After successful return of spontaneous circulation (N = 16), animals were randomized to either (1) propofol (CONTROL) anesthesia or (2) SEVO anesthesia for 4 hours. Neurological function was assessed 24 hours after return of spontaneous circulation. The effects on myocardial and cerebral damage, especially on inflammation, apoptosis and tissue remodeling, were studied using cellular and molecular approaches. Results Animals treated with SEVO had lower peak troponin T levels (median [IQR]) (CONTROL vs SEVO = 0.31 pg/mL [0.2 to 0.65] vs 0.14 pg/mL [0.09 to 0.25]; P < 0.05) and improved left ventricular systolic and diastolic function compared to the CONTROL group (P < 0.05). SEVO was associated with a reduction in myocardial IL-1β protein concentrations (0.16 pg/μg total protein [0.14 to 0.17] vs 0.12 pg/μg total protein [0.11 to 0.14]; P < 0.01), a reduction in apoptosis (increased procaspase-3 protein levels (0.94 arbitrary units [0.86 to 1.04] vs 1.18 arbitrary units [1.03 to 1.28]; P < 0.05), increased hypoxia-inducible factor (HIF)-1α protein expression (P < 0.05) and increased activity of matrix metalloproteinase 9 (P < 0.05). SEVO did not, however, affect neurological deficit score or cerebral cellular and molecular pathways. Conclusions SEVO reduced myocardial damage and dysfunction after cardiopulmonary resuscitation in the early postresuscitation period. The reduction was associated with a reduced rate of myocardial proinflammatory cytokine expression, apoptosis, increased HIF-1α expression and increased activity of matrix metalloproteinase 9. Early administration of SEVO may not, however, improve neurological recovery.
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Affiliation(s)
- Patrick Meybohm
- Department of Anaesthesiology and Intensive Care Medicine, Schleswig-Holstein University Hospital, Campus Kiel, Schwanenweg 21, D-24105 Kiel, Germany.
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Yung LM, Wei Y, Qin T, Wang Y, Smith CD, Waeber C. Sphingosine kinase 2 mediates cerebral preconditioning and protects the mouse brain against ischemic injury. Stroke 2011; 43:199-204. [PMID: 21980199 DOI: 10.1161/strokeaha.111.626911] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND AND PURPOSE Cerebral preconditioning provides insights into endogenous mechanisms that protect the brain from ischemic injury. Hypoxia and the anesthetic isoflurane are powerful preconditioning agents. Recent data show that sphingosine 1-phosphate receptor stimulation improves outcome in rodent models of stroke. Endogenous sphingosine 1-phosphate levels are controlled by the expression and activity of sphingosine kinases (SPK). We hypothesize that SPK upregulation mediates preconditioning induced by isoflurane and hypoxia and reduces ischemic injury. METHODS Male wild-type C57BL/J, SPK1(-/-) and SPK2(-/-) mice were exposed to isoflurane or hypoxia preconditioning before transient middle cerebral artery occlusion. Infarct volume and neurological outcome were measured 24 hours later. SPK inhibitors (SKI-II and ABC294640) were used to test the involvement of SPK2. Expressions of SPK1, SPK2, and hypoxia-inducible factor 1α were determined. Primary cultures of mouse cortical neurons were exposed to isoflurane before glutamate- or hydrogen peroxide-induced cell death. RESULTS Isoflurane preconditioning and hypoxia preconditioning significantly reduced infarct volume and improved neurological outcome in wild-type and SPK1(-/-) mice but not in SPK2(-/-) mice. Pretreatment with SKI-II or ABC294640 abolished the isoflurane preconditioning-induced tolerance. Western blot showed a rapid and sustained increase in SPK2 level, whereas SPK1 level was similar between preconditioned mice and controls. Hypoxia-inducible factor 1α was upregulated in wild-type isoflurane-preconditioned mice but not in SPK2(-/-). Isoflurane preconditioning protected primary neurons against cell death, which was abolished in ABC294640-treated cells. CONCLUSIONS Applying genetic and pharmacological approaches, we demonstrate that neuronal SPK2 isoform plays an important role in cerebral preconditioning.
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Affiliation(s)
- Lai Ming Yung
- Stroke and Neurovascular Regulation Laboratory, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
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Ansari S, Azari H, McConnell DJ, Afzal A, Mocco J. Intraluminal middle cerebral artery occlusion (MCAO) model for ischemic stroke with laser doppler flowmetry guidance in mice. J Vis Exp 2011:2879. [PMID: 21587164 DOI: 10.3791/2879] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Stroke is the third leading cause of death and the leading cause of disability in the world, with an estimated cost of near $70 billion in the United States in 2009. The intraluminal middle cerebral artery occlusion (MCAO) model was developed by Koizumi in 1986 to simulate this impactful human pathology in the rat. A modification of the MCAO method was later presented by Longa. Both techniques have been widely used to identify molecular mechanisms of brain injury resulting from ischemic stroke and potential therapeutic modalities. This relatively noninvasive method in rats has been extended to use in mice to take advantage of transgenic and knockout strains. To model focal cerebral ischemia, an intraluminal suture is advanced via the internal carotid artery to occlude the base of the MCA. Retracting the suture after a specified period of time mimics spontaneous reperfusion, but the suture can also be permanently retained. This video will be demonstrating the two major approaches for performing intraluminal MCAO procedure in mice in a stepwise fashion, as well as providing insights for potential drawbacks and pitfalls. The ischemic brain tissue will subsequently be stained by 2,3,5-triphenyltetrazolium chloride (TTC) to evaluate the extent of cerebral infarction.
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Affiliation(s)
- Saeed Ansari
- Department of Neurosurgery, University of Florida, USA.
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26
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Engel O, Kolodziej S, Dirnagl U, Prinz V. Modeling stroke in mice - middle cerebral artery occlusion with the filament model. J Vis Exp 2011:2423. [PMID: 21248698 PMCID: PMC3182649 DOI: 10.3791/2423] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Stroke is among the most frequent causes of death and adult disability, especially in highly developed countries. However, treatment options to date are very limited. To meet the need for novel therapeutic approaches, experimental stroke research frequently employs rodent models of focal cerebral ischaemia. Most researchers use permanent or transient occlusion of the middle cerebral artery (MCA) in mice or rats. Proximal occlusion of the middle cerebral artery (MCA) via the intraluminal suture technique (so called filament or suture model) is probably the most frequently used model in experimental stroke research. The intraluminal MCAO model offers the advantage of inducing reproducible transient or permanent ischaemia of the MCA territory in a relatively non-invasive manner. Intraluminal approaches interrupt the blood flow of the entire territory of this artery. Filament occlusion thus arrests flow proximal to the lenticulo-striate arteries, which supply the basal ganglia. Filament occlusion of the MCA results in reproducible lesions in the cortex and striatum and can be either permanent or transient. In contrast, models inducing distal (to the branching of the lenticulo-striate arteries) MCA occlusion typically spare the striatum and primarily involve the neocortex. In addition these models do require craniectomy. In the model demonstrated in this article, a silicon coated filament is introduced into the common carotid artery and advanced along the internal carotid artery into the Circle of Willis, where it blocks the origin of the middle cerebral artery. In patients, occlusions of the middle cerebral artery are among the most common causes of ischaemic stroke. Since varying ischemic intervals can be chosen freely in this model depending on the time point of reperfusion, ischaemic lesions with varying degrees of severity can be produced. Reperfusion by removal of the occluding filament at least partially models the restoration of blood flow after spontaneous or therapeutic (tPA) lysis of a thromboembolic clot in humans. In this video we will present the basic technique as well as the major pitfalls and confounders which may limit the predictive value of this model.
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Affiliation(s)
- Odilo Engel
- Department for Experimental Neurology, Center for Stroke Research Berlin, Charité Universitätsmedizin
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Bhuiyan MIH, Kim YJ. Mechanisms and prospects of ischemic tolerance induced by cerebral preconditioning. Int Neurourol J 2010; 14:203-12. [PMID: 21253330 PMCID: PMC3021810 DOI: 10.5213/inj.2010.14.4.203] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Accepted: 12/14/2010] [Indexed: 12/20/2022] Open
Abstract
In the brain, brief episodes of ischemia induce tolerance against a subsequent severe episode of ischemia. This phenomenon of endogenous neuroprotection is known as preconditioning-induced ischemic tolerance. The purpose of this review is to summarize the current state of knowledge about mechanisms and potential applications of cerebral preconditioning and ischemic tolerance. Articles related to the terms ischemic preconditioning and ischemic tolerance were systematically searched via MEDLINE/PubMed, and articles published in English related to the nervous system were selected and analyzed. The past two decades have provided interesting insights into the molecular mechanisms of this neuroprotective phenomenon. Although both rapid and delayed types of tolerance have been documented in experimental settings, the delayed type has been found to be more prominent in the case of neuronal ischemic tolerance. Many intracellular signaling pathways have been implicated regarding ischemic preconditioning. Most of these are associated with membrane receptors, kinase cascades, and transcription factors. Moreover, ischemic tolerance can be induced by exposing animals or cells to diverse types of endogenous and exogenous stimuli that are not necessarily hypoxic or ischemic in nature. These cross-tolerances raise the hope that, in the future, it will be possible to pharmacologically activate or mimic ischemic tolerance in the human brain. Another promising approach is remote preconditioning in which preconditioning of one organ or system leads to the protection of a different (remote) organ that is difficult to target, such as the brain. The preconditioning strategy and related interventions can confer neuroprotection in experimental ischemia, and, thus, have promise for practical applications in cases of vascular neurosurgery and endo-vascular therapy.
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Affiliation(s)
| | - Youn Jung Kim
- Kyung Hee University College of Nursing Science, Seoul, Korea
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Lee SY, Suh JK, Choi JH, Jeon WJ, Cheong MA. Effect of ketorolac and diclofenac on the impairment of endothelium-dependent relaxation induced by reactive oxygen species in rabbit abdominal aorta. Korean J Anesthesiol 2010; 59:196-202. [PMID: 20877705 PMCID: PMC2946038 DOI: 10.4097/kjae.2010.59.3.196] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Revised: 05/19/2010] [Accepted: 05/21/2010] [Indexed: 11/12/2022] Open
Abstract
Background Reactive oxygen species (ROS) induce lipid peroxidation and tissue damage in endothelium. We studied the influences of ketorolac and diclofenac on ROS effects using the endothelium of rabbit abdominal aorta. Methods Isolated rabbit aortic rings were suspended in an organ bath filled with Krebs-Henseleit (K-H) solution bubbled with 5% CO2 and 95% O2 at 37.5℃. After being stimulated to contract with phenylephrine (PE, 10-6 M), changes in arterial tension were recorded following the cumulative administration of acetylcholine (ACh, 3 × 10-8 to 10-6 M). The percentages of ACh-induced relaxation of aortic rings before and after exposure to ROS, generated by electrolysis of K-H solution, were used as the control and experimental values, respectively. The aortic rings were pretreated with ketorolac or diclofenac at the same concentrations (10-5 M to 3 × 10-4 M), and the effects of these agents were compared with the effects of ROS scavengers: catalase, mannitol, sodium salicylate and deferoxamine and the catalase inhibitor, 3-amino-1,2,4-triazole (3AT). Results Both ketorolac and diclofenac maintained endothlium-dependent relaxation induced by ACh in a dose-related manner inspite of ROS attack (P < 0.05 vs. control value). The 3AT pretreated ketorolac (3 × 10-3 M) group was decreased more significantly than un-pretreated ketorolac (P < 0.05). Conclusions These findings suggest that ketorlac and diclofenac preserve the endothelium-dependent vasorelaxation against the attack of ROS, in a concentration-related manner. One of the endothelial protection mechanisms of ketorolac may be hydrogen peroxide scavenging.
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Affiliation(s)
- Seung Yoon Lee
- Department of Anesthesiology and Pain Medicine, College of Medicine, Jeju University, Jeju, Korea
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Lee JM, Suh JK, Jeong JS, Cho SY, Kim DW. Antioxidant effect of lidocaine and procaine on reactive oxygen species-induced endothelial dysfunction in the rabbit abdominal aorta. Korean J Anesthesiol 2010; 59:104-10. [PMID: 20740215 PMCID: PMC2926425 DOI: 10.4097/kjae.2010.59.2.104] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Revised: 05/06/2010] [Accepted: 05/06/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Reactive oxygen species (ROS) induce lipid peroxidation and tissue damage in the endothelium. We tested the antioxidant effect of lidocaine and procaine on ROS-induced endothelial damage in the rabbit aorta. METHODS Aortic rings isolated from rabbits were suspended in an organ bath filled with Krebs-Henseleit (K-H) solution bubbled with 5% CO(2) and 95% O(2) at 37.5. After precontraction with phenylephrine (PE, 10(-6) M), changes in tension were recorded following a cumulative administration of acetylcholine (ACh 3 x 10(-8) to 10(-6) M). Differences were measured as percentages of ACh-induced relaxation of aortic rings before and after exposure to ROS as generated by electrolysis of the K-H solution. The aortic rings were pretreated with lidocaine or procaine (10(-5) M to 3 x 10(-3) M) to compare their effects, as well as ROS scavengers, catalase, mannitol, sodium salicylate, and deferoxamine, and a catalase inhibitor, 3-amino-1,2,4-triazole (3AT). RESULTS Lidocaine and procaine dose-dependently maintained endothelium-dependent relaxation induced by ACh despite ROS activity (P < 0.05 vs control value). The 3AT pretreated procaine (3 x 10(-3) M) group decreased more significantly than the un-pretreated procaine group (P < 0.05). CONCLUSIONS These findings suggest that lidocaine and procaine dose-dependently preserve endothelium-dependent vasorelaxation against ROS attack, potentially via hydrogen peroxide scavenging.
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Affiliation(s)
- Jae Myeong Lee
- Department of Anesthesiology and Pain Medicine, College of Medicine, Catholic University of Korea, Seoul, Korea
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Harten SK, Ashcroft M, Maxwell PH. Prolyl hydroxylase domain inhibitors: a route to HIF activation and neuroprotection. Antioxid Redox Signal 2010; 12:459-80. [PMID: 19737089 DOI: 10.1089/ars.2009.2870] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract Ischemic stroke is a major cause of death worldwide, and current therapeutic options are very limited. Preconditioning with an ischemic or hypoxic insult is beneficial in experimental models of ischemic stroke. Ischemia/hypoxia results in activation of numerous transcription factors, including hypoxia inducible factor (HIF), which is a master regulator of oxygen homeostasis. HIF activation induces a diverse range of target genes, encompassing a wide variety of cellular processes; including angiogenesis, energy metabolism, cell survival, radical production/scavenging, iron metabolism, stem cell homing, and differentiation. Inhibition of HIF prolyl hydroxylase domain (PHD) enzymes results in activation of HIF and is likely to mimic, at least in part, the effects of hypoxia preconditioning. A caveat is that not all consequences of HIF activation will be beneficial and some could even be deleterious. Nevertheless, PHD inhibitors may be therapeutically useful in the treatment of stroke. Prototype PHD inhibitors have shown promising results in preclinical models.
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Affiliation(s)
- Sarah K Harten
- Division of Medicine, Rayne Institute, University College London, University Street, London, United Kingdom.
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Liu XQ, Sheng R, Qin ZH. The neuroprotective mechanism of brain ischemic preconditioning. Acta Pharmacol Sin 2009; 30:1071-80. [PMID: 19617892 DOI: 10.1038/aps.2009.105] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Brain ischemia is one of the most common causes of death and the leading cause of adult disability in the world. Brain ischemic preconditioning (BIP) refers to a transient, sublethal ischemia which results in tolerance to later, otherwise lethal, cerebral ischemia. Many attempts have been made to understand the molecular and cellular mechanisms underlying the neuroprotection offered by ischemic preconditioning. Many studies have shown that neuroprotective mechanisms may involve a series of molecular regulatory pathways including activation of the N-methyl-D-aspartate (NMDA) and adenosine receptors; activation of intracellular signaling pathways such as mitogen activated protein kinases (MAPK) and other protein kinases; upregulation of Bcl-2 and heat shock proteins (HSPs); and activation of the ubiquitin-proteasome pathway and the autophagic-lysosomal pathway. A better understanding of the processes that lead to cell death after stroke as well as of the endogenous neuroprotective mechanisms by which BIP protects against brain ischemic insults could help to develop new therapeutic strategies for this devastating neurological disease. The purpose of the present review is to summarize the neuroprotective mechanisms of BIP and to discuss the possibility of mimicking ischemic preconditioning as a new strategy for preventive treatment of ischemia.
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Ritz MF, Schmidt P, Mendelowitsch A. EFFECTS OF ISOFLURANE ON GLUTAMATE AND TAURINE RELEASES, BRAIN SWELLING AND INJURY DURING TRANSIENT ISCHEMIA AND REPERFUSION. Int J Neurosci 2009; 116:191-202. [PMID: 16393884 DOI: 10.1080/00207450500341555] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The volatile anesthetic agent isoflurane was thought to provide neuroprotection against ischemic damage; however, this effect remains controversial. Using the middle cerebral artery occlusion model and intracerebral microdialysis, the authors monitored the variations of glutamate and taurine concentrations in the extra-cellular space in male rats anesthetized with pentobarbital or isoflurane. Brain injury and edema were evaluated 24 h after ischemia. Isoflurane prevented the ischemia-induced efflux of glutamate and reduced the release of taurine. No difference in the size of the brain lesions was observed with both anesthetics, and isoflurane induced the formation of a bigger brain edema and reduced taurine release. These results suggest that inhibiting glutamate release during ischemia may not be sufficient to improve brain outcome after transient ischemia.
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Affiliation(s)
- Marie-Françoise Ritz
- Department of Research, Neurosurgery Laboratory, University Hospital, Basel, Switzerland.
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Dirnagl U, Becker K, Meisel A. Preconditioning and tolerance against cerebral ischaemia: from experimental strategies to clinical use. Lancet Neurol 2009; 8:398-412. [PMID: 19296922 DOI: 10.1016/s1474-4422(09)70054-7] [Citation(s) in RCA: 455] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Neuroprotection and brain repair in patients after acute brain damage are still major unfulfilled medical needs. Pharmacological treatments are either ineffective or confounded by adverse effects. Consequently, endogenous mechanisms by which the brain protects itself against noxious stimuli and recovers from damage are being studied. Research on preconditioning, also known as induced tolerance, over the past decade has resulted in various promising strategies for the treatment of patients with acute brain injury. Several of these strategies are being tested in randomised clinical trials. Additionally, research into preconditioning has led to the idea of prophylactically inducing protection in patients such as those undergoing brain surgery and those with transient ischaemic attack or subarachnoid haemorrhage who are at high risk of brain injury in the near future. In this Review, we focus on the clinical issues relating to preconditioning and tolerance in the brain; specifically, we discuss the clinical situations that might benefit from such procedures. We also discuss whether preconditioning and tolerance occur naturally in the brain and assess the most promising candidate strategies that are being investigated.
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Affiliation(s)
- Ulrich Dirnagl
- Department of Neurology, Center for Stroke Research, Charite Universitätsmedizin Berlin, Charitéplatz, D-10098, Berlin, Germany.
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Wegener S, Wong EC. Longitudinal MRI studies in the isoflurane-anesthetized rat: long-term effects of a short hypoxic episode on regulation of cerebral blood flow as assessed by pulsed arterial spin labelling. NMR IN BIOMEDICINE 2008; 21:696-703. [PMID: 18275045 DOI: 10.1002/nbm.1243] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
MRI is a powerful tool for measuring cerebral blood flow (CBF) longitudinally. However, most animal studies require anesthesia, potentially interfering with normal physiology. Isoflurane anesthesia was used here to study CBF regulation during repetitive scanning in rats. MR perfusion images were acquired using FAIR (flow-sensitive alternating inversion recovery) arterial spin labeling, and absolute CBF was calculated. CBF changes in response to a hypoxic (12% O2) and hypercapnic (5% CO2) gas stimulus were monitored. Hypercapnia led to a robust increase in CBF compared with baseline (195.5+/-21.5 vs 123.6+/-17.9 ml/100 g/min), and hypoxia caused a smaller non-significant increase in mean CBF values (145.4+/-13.4 ml/100 g/min). Strikingly, when measurements were repeated 5 days later, CBF was dramatically reduced in hypoxia (93.2+/-8.1 ml/100 g/min) compared with the first imaging session. Without application of the hypoxic and hypercapnic gases during the first MRI, baseline CBF and CBF changes in response to hypoxia at the second MRI were similar to naive rats. Blood gas analyses revealed a slight reduction in arterial oxygenation during the second period of anesthesia compared with the first. These findings indicate that, in isoflurane-anesthetized rats, even a short hypoxic episode can have long-lasting effects on cerebrovascular regulation.
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Affiliation(s)
- Susanne Wegener
- Department of Radiology, University of California at San Diego, San Diego, CA 92103, USA.
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Wang L, Traystman RJ, Murphy SJ. Inhalational anesthetics as preconditioning agents in ischemic brain. Curr Opin Pharmacol 2007; 8:104-10. [PMID: 17962069 DOI: 10.1016/j.coph.2007.09.005] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2007] [Revised: 09/14/2007] [Accepted: 09/17/2007] [Indexed: 10/22/2022]
Abstract
While many pharmacological agents have been shown to protect the brain from cerebral ischemia in animal models, none have translated successfully to human patients. One potential clinical neuroprotective strategy in humans may involve increasing the brain's tolerance to ischemia by preischemic conditioning (preconditioning). There are many methods to induce tolerance via preconditioning such as ischemia itself, pharmacological, hypoxia, endotoxin, and others. Inhalational anesthetic agents have also been shown to result in brain preconditioning. Mechanisms responsible for brain preconditioning are many, complex, and unclear and may involve Akt activation, ATP-sensitive potassium channels, and nitric oxide, amongst many others. Anesthetics, however, may play an important and unique role as preconditioning agents, particularly during the perioperative period.
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Affiliation(s)
- Lan Wang
- Oregon Health and Science University, Department of Anesthesiology and Peri-Operative Medicine, 3181 SW Sam Jackson Park Road, Portland, OR 97239-3098, USA
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Burd R, Wachsberger P. Application of radiotherapy and chemotherapy protocols to pre-clinical tumor models. ACTA ACUST UNITED AC 2007; Chapter 14:Unit 14.7. [PMID: 21948166 DOI: 10.1002/0471141755.ph1407s38] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
This unit (1) provides background into understanding how agents that target specific molecules or receptors (molecular-targeted agents), in particular, agents affecting the tumor vasculature (perivasculature network in tumors), interact with and modify radiation therapy; (2) details factors affecting interpretation of results in murine tumor model experiments utilizing radiation therapy and drug combinations; and (3) provides specific protocols for the application of radiation therapy, both alone and in combination with chemotherapy and/or molecular-targeted agents.
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Affiliation(s)
- Randy Burd
- University of Arizona, Tucson, Arizona, USA
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37
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Kitano H, Kirsch JR, Hurn PD, Murphy SJ. Inhalational anesthetics as neuroprotectants or chemical preconditioning agents in ischemic brain. J Cereb Blood Flow Metab 2007; 27:1108-28. [PMID: 17047683 PMCID: PMC2266688 DOI: 10.1038/sj.jcbfm.9600410] [Citation(s) in RCA: 145] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
This review will focus on inhalational anesthetic neuroprotection during cerebral ischemia and inhalational anesthetic preconditioning before ischemic brain injury. The limitations and challenges of past and current research in this area will be addressed before reviewing experimental and clinical studies evaluating the effects of inhalational anesthetics before and during cerebral ischemia. Mechanisms underlying volatile anesthetic neuroprotection and preconditioning will also be examined. Lastly, future directions for inhalational anesthetics and ischemic brain injury will be briefly discussed.
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Affiliation(s)
- Hideto Kitano
- Department of Anesthesiology and Peri-Operative Medicine, Oregon Health and Science University, Portland, Oregon 97239, USA
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Steiger HJ, Hänggi D. Ischaemic preconditioning of the brain, mechanisms and applications. Acta Neurochir (Wien) 2007; 149:1-10. [PMID: 17151832 DOI: 10.1007/s00701-006-1057-1] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2006] [Accepted: 10/11/2006] [Indexed: 01/25/2023]
Abstract
BACKGROUND The concept of ischaemic preconditioning was introduced in the late 1980s. The concept emerged that a brief subcritical ischaemic challenge could mobilize intrinsic protective mechanisms that increased tolerance against subsequent critical ischaemia. Tissues with a high sensitivity against ischaemia, i.e. myocardium and central nervous system, present the most promising targets for therapeutic application of ischaemic preconditioning. During the last years the mechanisms of neuronal preconditioning were systematically studied and a number of molecular regulation pathways were discovered to participate in preconditioning. The purpose of the present review is to survey the actual knowledge on cerebral preconditioning, and to define the practical impact for neurosurgery. METHODS A systematic medline search for the terms preconditioning and postconditioning was filed. Publications related to the nervous system were selected and analysed. FINDINGS Preconditioning can be subdivided into early and late mechanisms, depending on whether the effect appears immediately after the nonlethal stress or with a delay of some hours or days. In general early effects can be linked to adaptation of membrane receptors whereas late effects are the result of gene up- or downregulation. Not only subcritical ischaemia can trigger preconditioning but also hypoxia, hyperthermia, isoflurane and other chemical substances. Although a vast amount of knowledge has been accumulated regarding neural preconditioning, it is unknown whether the effects can be potentiated by pharmacological or hypothermic neuroprotection during the critical ischaemia. Furthermore, although the practical importance of these findings is obvious, the resulting protective manipulations have so far not been transferred into clinical neurosurgery. Postconditioning and remote ischaemic preconditioning are additional emerging concepts. Postconditioning with a series of mechanical interruptions of reperfusion can apparently reduce ischaemic damage. Remote ischaemic preconditioning refers to the concept that transient ischaemia for example of a limb can lead to protection of the myocardium and possibly the brain. CONCLUSION Possible cumulative neuroprotection by preconditioning and pharmacological protection during critical ischaemia should be studied systematically. Easy to apply methods of preconditioning, such as the application of volatile anaesthetics or erythropoietin some hours or days prior to planned temporary ischaemia, should be introduced into the practice of operative neurosurgery.
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Affiliation(s)
- H-J Steiger
- Department of Neurosurgery, University Hospital, Heinrich-Heine University, Düsseldorf, Germany.
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Wen B, Urano M, O'Donoghue JA, Ling CC. Measurements of partial oxygen pressure pO2 using the OxyLite system in R3327-AT tumors under isoflurane anesthesia. Radiat Res 2006; 166:512-8. [PMID: 16953670 DOI: 10.1667/rr3602.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The presence of oxygen-deficient tumor cells is a critical issue in cancer therapy. To identify tumor hypoxia, tissue partial oxygen pressure (pO2) can be measured directly. The OxyLite system allows determination of pO2 in tumors and permits continuous measurements of pO2 at a fixed point. In this study, this system was used to continuously measure pO2 in R3327-AT tumors in animals anesthetized with isoflurane. In addition, continuous pO2 measurement was performed in the muscle in non-tumor-bearing animals. In animals breathing isoflurane balanced by air, tumor pO2 at fixed positions decreased rapidly within 1-2 min of probe positioning but remained stable thereafter. In animals breathing isoflurane balanced by pure oxygen, tumor pO2 was higher and remained high. We also measured pO2 values at multiple positions in R3327-AT tumors of various sizes, with anesthetized animals breathing either air or pure oxygen. Our data showed that the frequency of pO2 measurements below 2.5 or 5.0 mmHg was significantly higher in animals breathing air than in animals breathing pure oxygen. Measurements in different-sized tumors showed that the mean pO2 value decreased as tumor volume increased, with the largest change occurring between tumor volumes of 100 and 200 mm3. Our data demonstrate that the OxyLite system, when used with isoflurane anesthesia, is a valuable tool in the study of tumor hypoxia.
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Affiliation(s)
- Bixiu Wen
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
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Nasu I, Yokoo N, Takaoka S, Takata K, Hoshikawa T, Okada M, Miura Y. The Dose-Dependent Effects of Isoflurane on Outcome from Severe Forebrain Ischemia in the Rat. Anesth Analg 2006; 103:413-8, table of contents. [PMID: 16861426 DOI: 10.1213/01.ane.0000223686.50202.38] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Isoflurane improves outcome against cerebral ischemia in the rat. However, the optimal neuroprotective concentration has not been defined. We examined the effects of different isoflurane concentrations on outcome from severe forebrain ischemia in the rat. Fasted rats were subjected to 0.5, 1.0, 1.5, 2.0, or 2.5 minimum alveolar concentration (MAC) isoflurane during 10 min bilateral carotid occlusion plus systemic hypotension. Each isoflurane concentration was administered only before ischemia. Arterial blood pressure was not pharmacologically manipulated. After ischemia, the anesthetic regimen was changed to fentanyl/nitrous oxide and maintained for 2 h. Pericranial temperature was maintained normothermic during the experiment. Neuromotor score, % dead hippocampal CA1 neurons, and cortical injury were measured 5 days postischemia. Preischemic arterial blood pressure decreased as MAC was increased. Animals administered >1.0 MAC frequently exhibited postischemic seizures resulting in increased mortality. There was no difference among MAC conditions for % dead CA1 neurons (93 approximately 95%). In the cortex, neuronal necrosis was less severe with 0.5 MAC and 1.0 MAC isoflurane relative to >1.0 MAC values. The neuromotor score in the 1.0 MAC isoflurane group was superior to the 2.5 MAC group. Dose-dependent effects of preischemic administration of isoflurane on histologic and behavioral outcome after severe forebrain ischemia were observed. Isoflurane MAC values <1.5 provided superior overall outcome relative to larger isoflurane concentrations.
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Affiliation(s)
- Ikuko Nasu
- Department of Anesthesiology, Yamagata University School of Medicine, Yamagata, Japan
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Dave KR, Saul I, Prado R, Busto R, Perez-Pinzon MA. Remote organ ischemic preconditioning protect brain from ischemic damage following asphyxial cardiac arrest. Neurosci Lett 2006; 404:170-5. [PMID: 16781056 DOI: 10.1016/j.neulet.2006.05.037] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2006] [Revised: 04/26/2006] [Accepted: 05/18/2006] [Indexed: 11/25/2022]
Abstract
Ischemic preconditioning (IPC) is a phenomenon whereby an organ's adaptive transient resistance to a lethal ischemic insult occurs by preconditioning this organ with a sub-lethal/mild ischemic insult of short duration. Besides IPC, recent studies reported that a short sub-lethal ischemia and reperfusion in various organs can induce ischemic tolerance in another organ as well. This phenomenon is known as remote ischemic preconditioning (RPC). In the present study we tested the hypothesis that tolerance for ischemia can be induced in brain by RPC and IPC in a rat model of asphyxial cardiac arrest (ACA). RPC was induced by tightening the upper two-thirds of both hind limbs using a tourniquet for 15 or 30 min and IPC was induced by tightening bilateral carotid artery ligatures for 2 min. Eight minutes of ACA was induced 48 h after RPC or IPC. After 7 day of resuscitation, brains were extracted and examined for histopathological changes. In CA1 hippocampus, the number of normal neurons was 63% lower in cardiac-arrested rats as compared to the control group. The number of normal neurons in the 15 min RPC, 30 min RPC, and IPC groups was higher than the ACA group by 54, 70, and 67%, respectively. This study demonstrates that RPC and IPC are able to provide neuroprotection in a rat model of ACA. Besides direct application of RPC or IPC paradigms, the exploration of the mechanisms of observed neuroprotection by RPC and IPC may also lead to a possible therapy for CA patients.
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Affiliation(s)
- Kunjan R Dave
- Cerebral Vascular Disease Research Center, Department of Neuroscience, University of Miami Miller School of Medicine, FL 33101, USA.
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Sharp FR, Ran R, Lu A, Tang Y, Strauss KI, Glass T, Ardizzone T, Bernaudin M. Hypoxic preconditioning protects against ischemic brain injury. NeuroRx 2005; 1:26-35. [PMID: 15717005 PMCID: PMC534910 DOI: 10.1602/neurorx.1.1.26] [Citation(s) in RCA: 162] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Animals exposed to brief periods of moderate hypoxia (8% to 10% oxygen for 3 hours) are protected against cerebral and cardiac ischemia between 1 and 2 days later. This hypoxia preconditioning requires new RNA and protein synthesis. The mechanism of this hypoxia-induced tolerance correlates with the induction of the hypoxia-inducible factor (HIF), a transcription factor heterodimeric complex composed of inducible HIF-1alpha and constitutive HIF-1beta proteins that bind to the hypoxia response elements in a number of HIF target genes. Our recent studies show that HIF-1alpha correlates with hypoxia induced tolerance in neonatal rat brain. HIF target genes, also induced following hypoxia-induced tolerance, include vascular endothelial growth factor, erythropoietin, glucose transporters, glycolytic enzymes, and many other genes. Some or all of these genes may contribute to hypoxia-induced protection against ischemia. HIF induction of the glycolytic enzymes accounts in part for the Pasteur effect in brain and other tissues. Hypoxia-induced tolerance is not likely to be equivalent to treatment with a single HIF target gene protein since other transcription factors including Egr-1 (NGFI-A) have been implicated in hypoxia regulation of gene expression. Understanding the mechanisms and genes involved in hypoxic tolerance may provide new therapeutic targets to treat ischemic injury and enhance recovery.
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Affiliation(s)
- Frank R Sharp
- Department of Neurology, University of Cincinnati, Ohio 45267, USA.
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Abstract
Endogenous tolerance to cerebral ischemia is nature's strategy for neuroprotection. Exploring the physiologic and molecular mechanism of this phenomenon may give us new means of protection against ischemia and other degenerative disorders. This article reviews the currently available experimental methods to induce ischemic tolerance in the brain and gives a brief summary of the potential mode of action.
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Affiliation(s)
- K J Kapinya
- Department of Experimental Neurology, Medical Faculty Charité, Humboldt-University, Berlin, Germany.
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Tomita Y, Kubis N, Calando Y, Tran Dinh A, Méric P, Seylaz J, Pinard E. Long-term in vivo investigation of mouse cerebral microcirculation by fluorescence confocal microscopy in the area of focal ischemia. J Cereb Blood Flow Metab 2005; 25:858-67. [PMID: 15758950 DOI: 10.1038/sj.jcbfm.9600077] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This study was designed to assess that mouse pial and cortical microcirculation can be monitored in the long term directly in the area of focal ischemia, using in vivo fluorescence microscopy. A closed cranial window was placed over the left parieto-occipital cortex of C57BL/6J mice. Local microcirculation was recorded in real time through the window using laser-scanning confocal fluorescence microscopy after intravenous injection of fluorescent erythrocytes and dextran. The basal velocity of erythrocytes through intraparenchymal capillaries was 0.53+/-0.30 mm/sec (n=121 capillaries in 10 mice). Two branches of the middle cerebral artery were topically cauterized through the window. Blood flow evaluated by laser-Doppler flowmetry in two distinct areas indicated the occurrence of an ischemic core (15.2%+/-5.9% of baseline for at least 2 h) and a penumbral zone. Magnetic resonance imaging and histology were used to characterize the ischemic area at 24 h after occlusion. The infarct volume was 7.3+/-3.2 mm(3) (n=6). Microcirculation was repeatedly videorecorded using fluorescence confocal microscopy over the next month. After the decrease following arterial occlusion, capillary erythrocyte velocity was significantly higher than baseline 1 week later, and attained 0.74+/-0.51 mm/sec (n=76 capillaries in six mice, P<0.005) after 1 month, while venous and capillary network remodeling was assessed, with a marked decrease in tortuosity. Immunohistochemistry revealed a zone of necrotic tissue into the infarct epicenter, with activated astrocytes at its border. Such long-term investigations in ischemic cortex brings new insight into the microcirculatory changes induced by focal ischemia and show the feasibility of long-term fluorescence studies in the mouse cortex.
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Affiliation(s)
- Yutaka Tomita
- Laboratoire de Biologie et Physiologie Moléculaire du Vaisseau, Paris, France
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Warner DS, Sheng H, Batinić-Haberle I. Oxidants, antioxidants and the ischemic brain. ACTA ACUST UNITED AC 2004; 207:3221-31. [PMID: 15299043 DOI: 10.1242/jeb.01022] [Citation(s) in RCA: 415] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Despite numerous defenses, the brain is vulnerable to oxidative stress resulting from ischemia/reperfusion. Excitotoxic stimulation of superoxide and nitric oxide production leads to formation of highly reactive products, including peroxynitrite and hydroxyl radical, which are capable of damaging lipids, proteins and DNA. Use of transgenic mutants and selective pharmacological antioxidants has greatly increased understanding of the complex interplay between substrate deprivation and ischemic outcome. Recent evidence that reactive oxygen/nitrogen species play a critical role in initiation of apoptosis, mitochondrial permeability transition and poly(ADP-ribose) polymerase activation provides additional mechanisms for oxidative damage and new targets for post-ischemic therapeutic intervention. Because oxidative stress involves multiple post-ischemic cascades leading to cell death, effective prevention/treatment of ischemic brain injury is likely to require intervention at multiple effect sites.
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Affiliation(s)
- David S Warner
- Department of Anesthesiology, The Multidisciplinary Neuroprotection Laboratories, Duke University Medical Center, Durham, NC 27710, USA.
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Olson EE, McKeon RJ. Characterization of cellular and neurological damage following unilateral hypoxia/ischemia. J Neurol Sci 2004; 227:7-19. [PMID: 15546586 DOI: 10.1016/j.jns.2004.07.021] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2004] [Revised: 05/07/2004] [Accepted: 07/21/2004] [Indexed: 11/15/2022]
Abstract
Rodent models of stroke are often used to investigate the mechanisms that lead to ischemic neuronal damage. In this study, we used a model of cerebral hypoxia with ischemia to produce unilateral damage in C57Bl/6 mice. Lesion volume, ascertained by TTC staining, increased with longer durations of hypoxia. Additionally, cresyl violet, TUNEL, and FluoroJade staining showed a statistically significant increase in cellular damage in the ipsilateral cortex, CA1 pyramidal layer, and dentate gyrus of the hippocampus of ipsilateral hypoxic/ischemic tissue versus sham tissue. Astrocyte reactivity, determined by GFAP staining, was significantly higher in the ipsilateral H/I cortex and contralateral hippocampus compared to sham cortex and hippocampus, respectively. Increased microglia activation was evident in the H/I-treated cortex and hippocampus versus sham cortex and hippocampus, particularly within areas undergoing degeneration. To examine whether this model produces motor deficits, a battery of tests were administered before and after hypoxia. Following 45 min H/I, locomotor activity, rotarod performance and performance on an inverted wire hang test were all significantly decreased. These data indicate that the histological evidence of neuronal damage is consistent with functional deficits and suggest that this model may be useful for investigating strategies designed to protect neurons from hypoxia/ischemia-induced damage.
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Affiliation(s)
- E E Olson
- Emory University, Department of Cell Biology, Whitehead Biomedical Research Building, 615 Michael Street, Atlanta, GA, 30322, USA
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Karikó K, Weissman D, Welsh FA. Inhibition of toll-like receptor and cytokine signaling--a unifying theme in ischemic tolerance. J Cereb Blood Flow Metab 2004; 24:1288-304. [PMID: 15545925 DOI: 10.1097/01.wcb.0000145666.68576.71] [Citation(s) in RCA: 200] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cerebral ischemia triggers acute inflammation, which exacerbates primary brain damage. Activation of the innate immune system is an important component of this inflammatory response. Inflammation occurs through the action of proinflammatory cytokines, such as TNF, IL-1 beta and IL-6, that alter blood flow and increase vascular permeability, thus leading to secondary ischemia and accumulation of immune cells in the brain. Production of these cytokines is initiated by signaling through Toll-like receptors (TLRs) that recognize host-derived molecules released from injured tissues and cells. Recently, great strides have been made in understanding the regulation of the innate immune system, particularly the signaling mechanisms of TLRs. Negative feedback inhibitors of TLRs and inflammatory cytokines have now been identified and characterized. It is also evident that lipid rafts exist in membranes and play a role in receptor-mediated inflammatory signaling events. In the present review, using this newly available large body of knowledge, we take a fresh look at studies of ischemic tolerance. Based on this analysis, we recognize a striking similarity between ischemic tolerance and endotoxin tolerance, an immune suppressive state characterized by hyporesponsiveness to lipopolysaccharide (LPS). In view of this analogy, and considering recent discoveries related to molecular mechanisms of endotoxin tolerance, we postulate that inhibition of TLR and proinflammatory cytokine signaling contributes critically to ischemic tolerance in the brain and other organs. Ischemic tolerance is a protective mechanism induced by a variety of preconditioning stimuli. Tolerance can be established with two temporal profiles: (i) a rapid form in which the trigger induces tolerance to ischemia within minutes and (ii) a delayed form in which development of protection takes several hours or days and requires de-novo protein synthesis. The rapid form of tolerance is achieved by direct interference with membrane fluidity, causing disruption of lipid rafts leading to inhibition of TLR/cytokine signaling pathways. In the delayed form of tolerance, the preconditioning stimulus first triggers the TLR/cytokine inflammatory pathways, leading not only to inflammation but also to simultaneous upregulation of feedback inhibitors of inflammation. These inhibitors, which include signaling inhibitors, decoy receptors, and anti-inflammatory cytokines, reduce the inflammatory response to a subsequent episode of ischemia. This novel interpretation of the molecular mechanism of ischemic tolerance highlights new avenues for future investigation into the prevention and treatment of stroke and related diseases.
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Affiliation(s)
- Katalin Karikó
- Department of Neurosurgery, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
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Hypoxic preconditioning protects against ischemic brain injury. Neurotherapeutics 2004. [DOI: 10.1007/bf03206565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Abstract
PURPOSE OF REVIEW Brain ischemia is responsible for significant morbidity and mortality associated with cardiovascular surgery, and is the end result of multiple disease states, including cardiac arrest, stroke, and traumatic brain injury. Despite significant resources dedicated to developing neuroprotective strategies, little progress has been made in this regard. Neuronal ischemic preconditioning is an endogenous neuroprotective strategy that provides sustained and robust ischemic tolerance. Identification of the mechanisms responsible for mediating the preconditioning response may offer novel therapeutic targets and further our understanding of the natural adaptations to brain injury. RECENT FINDINGS Recent research efforts have elucidated many intracellular signaling pathways that ultimately lead to ischemic tolerance after a preconditioning stimulus. Most of these are associated with glutamate receptor signal transduction, the intracellular kinases, and several transcription regulators. Microarray analysis has identified several gene families that warrant further investigation to identify novel candidates for neuroprotective therapies. These include genes involved in synaptic architecture and signal propagation, cell cycle and transcription regulators, and mediators of apoptosis such as the heat shock proteins and anti-apoptotic mitochondrial proteins. SUMMARY Neuronal ischemic preconditioning is an endogenous mechanism that leads to robust neuroprotection from ischemia. Identification of the upstream pathways that initiate preconditioning and candidate genes that mediate this phenomenon may offer novel therapeutic targets, with applicability to a variety of disease states and perioperative complications.
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Affiliation(s)
- Daniel P Davis
- Department of Emergency Medicine, University of California, San Diego, California, USA
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