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Taylor E, Hill RP, Létourneau D. Modeling the impact of spatial oxygen heterogeneity on radiolytic oxygen depletion during FLASH radiotherapy. Phys Med Biol 2022; 67. [PMID: 35576920 DOI: 10.1088/1361-6560/ac702c] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 05/16/2022] [Indexed: 12/12/2022]
Abstract
Purpose.It has been postulated that the delivery of radiotherapy at ultra-high dose rates ('FLASH') reduces normal tissue toxicities by depleting them of oxygen. The fraction of normal tissue and cancer cells surviving radiotherapy depends on dose and oxygen levels in an exponential manner and even a very small fraction of tissue at low oxygen levels can determine radiotherapy response. To quantify the differential impact of FLASH radiotherapy on normal and tumour tissues, the spatial heterogeneity of oxygenation in tissue should thus be accounted for.Methods.The effect of FLASH on radiation-induced normal and tumour tissue cell killing was studied by simulating oxygen diffusion, metabolism, and radiolytic oxygen depletion (ROD) over domains with simulated capillary architectures. To study the impact of heterogeneity, two architectural models were used: (1) randomly distributed capillaries and (2) capillaries forming a regular square lattice array. The resulting oxygen partial pressure distribution histograms were used to simulate normal and tumour tissue cell survival using the linear quadratic model of cell survival, modified to incorporate oxygen-enhancement ratio effects. The ratio ('dose modifying factors') of conventional low-dose-rate dose and FLASH dose at iso-cell survival was computed and compared with empirical iso-toxicity dose ratios.Results.Tumour cell survival was found to be increased by FLASH as compared to conventional radiotherapy, with a 0-1 order of magnitude increase for expected levels of tumour hypoxia, depending on the relative magnitudes of ROD and tissue oxygen metabolism. Interestingly, for the random capillary model, the impact of FLASH on well-oxygenated (normal) tissues was found to be much greater, with an estimated increase in cell survival by up to 10 orders of magnitude, even though reductions in mean tissue partial pressure were modest, less than ∼7 mmHg for the parameter values studied. The dose modifying factor for normal tissues was found to lie in the range 1.2-1.7 for a representative value of normal tissue oxygen metabolic rate, consistent with preclinical iso-toxicity results.Conclusions.The presence of very small nearly hypoxic regions in otherwise well-perfused normal tissues with high mean oxygen levels resulted in a greater proportional sparing of normal tissue than tumour cells during FLASH irradiation, possibly explaining empirical normal tissue sparing and iso-tumour control results.
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Affiliation(s)
- Edward Taylor
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Ontario, Canada.,Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
| | - Richard P Hill
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Ontario, Canada.,Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Daniel Létourneau
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Ontario, Canada.,Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
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Malinova V, Iliev B, Tsogkas I, Rohde V, Psychogios MN, Mielke D. Assessment of tissue permeability by early CT perfusion as a surrogate parameter for early brain injury after subarachnoid hemorrhage. J Neurosurg 2020; 133:808-813. [PMID: 31443075 DOI: 10.3171/2019.5.jns19765] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Accepted: 05/30/2019] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The severity of early brain injury (EBI) after aneurysmal subarachnoid hemorrhage (aSAH) correlates with delayed cerebral ischemia (DCI) and outcome. A disruption of the blood-brain barrier is part of EBI pathophysiology. The aim of this study was to assess tissue permeability (PMB) by CT perfusion (CTP) in the acute phase after aSAH and its impact on DCI and outcome. METHODS CTP was performed on day 3 after aSAH. Qualitative and quantitative analyses of all CTP parameters, including PMB, were performed. The areas with increased PMB were documented. The value of an early PMB increase as a predictor of DCI and outcome according to the modified Rankin Scale (mRS) grade 3 to 24 months after aSAH was assessed. Possible associations of increased PMB with the Subarachnoid Hemorrhage Early Brain Edema Score (SEBES) and with early perfusion deficits, as radiographic EBI markers, were evaluated. RESULTS A total of 69 patients were enrolled in the study. An increased PMB on early CTP was detected in 10.1% (7/69) of all patients. A favorable outcome (mRS grade ≤ 2) occurred in 40.6% (28/69) of all patients. DCI was detected in 25% (17/69) of all patients. An increased PMB was a predictor of DCI (logistic regression, p = 0.03) but not of outcome (logistic regression, p = 0.40). The detection of increased PMB predicted DCI with a sensitivity of 25%, a specificity of 94%, a positive predictive value of 57%, and a negative predictive value of 79% (chi-square test p = 0.03). Early perfusion deficits were seen in 68.1% (47/69) of the patients, a finding that correlated with DCI (p = 0.005) but not with the outcome. No correlation was found between the SEBES and increased PMB. CONCLUSIONS Changes in PMB can be detected by early CTP after aSAH, which correlates with DCI. Future studies are needed to evaluate the time course of PMB changes and their interaction with therapeutic measures.
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Affiliation(s)
| | | | - Ioannis Tsogkas
- 2Neuroradiology, Georg-August-University, Göttingen, Germany; and
| | | | - Marios-Nikos Psychogios
- 2Neuroradiology, Georg-August-University, Göttingen, Germany; and
- 3Department of Neuroradiology, University Hospital Basel, Switzerland
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Abstract
Haemoglobin is released into the CNS during the breakdown of red blood cells after intracranial bleeding. Extracellular free haemoglobin is directly neurotoxic. Haemoglobin scavenging mechanisms clear haemoglobin and reduce toxicity; these mechanisms include erythrophagocytosis, haptoglobin binding of haemoglobin, haemopexin binding of haem and haem oxygenase breakdown of haem. However, the capacity of these mechanisms is limited in the CNS, and they easily become overwhelmed. Targeting of haemoglobin toxicity and scavenging is, therefore, a rational therapeutic strategy. In this Review, we summarize the neurotoxic mechanisms of extracellular haemoglobin and the peculiarities of haemoglobin scavenging pathways in the brain. Evidence for a role of haemoglobin toxicity in neurological disorders is discussed, with a focus on subarachnoid haemorrhage and intracerebral haemorrhage, and emerging treatment strategies based on the molecular pathways involved are considered. By focusing on a fundamental biological commonality between diverse neurological conditions, we aim to encourage the application of knowledge of haemoglobin toxicity and scavenging across various conditions. We also hope that the principles highlighted will stimulate research to explore the potential of the pathways discussed. Finally, we present a consensus opinion on the research priorities that will help to bring about clinical benefits.
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McConnell HL, Li Z, Woltjer RL, Mishra A. Astrocyte dysfunction and neurovascular impairment in neurological disorders: Correlation or causation? Neurochem Int 2019; 128:70-84. [PMID: 30986503 DOI: 10.1016/j.neuint.2019.04.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 04/08/2019] [Accepted: 04/09/2019] [Indexed: 12/14/2022]
Abstract
The neurovascular unit, consisting of neurons, astrocytes, and vascular cells, has become the focus of much discussion in the last two decades and emerging literature now suggests an association between neurovascular dysfunction and neurological disorders. In this review, we synthesize the known and suspected contributions of astrocytes to neurovascular dysfunction in disease. Throughout the brain, astrocytes are centrally positioned to dynamically mediate interactions between neurons and the cerebral vasculature, and play key roles in blood-brain barrier maintenance and neurovascular coupling. It is increasingly apparent that the changes in astrocytes in response to a variety of insults to brain tissue -collectively referred to as "reactive astrogliosis" - are not just an epiphenomenon restricted to morphological alterations, but comprise functional changes in astrocytes that contribute to the phenotype of neurological diseases with both beneficial and detrimental effects. In the context of the neurovascular unit, astrocyte dysfunction accompanies, and may contribute to, blood-brain barrier impairment and neurovascular dysregulation, highlighting the need to determine the exact nature of the relationship between astrocyte dysfunction and neurovascular impairments. Targeting astrocytes may represent a new strategy in combinatorial therapeutics for preventing the mismatch of energy supply and demand that often accompanies neurological disorders.
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Affiliation(s)
- Heather L McConnell
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, United States
| | - Zhenzhou Li
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, United States; Department of Anesthesiology, General Hospital of Ningxia Medical University, Yinchuan City, China
| | - Randall L Woltjer
- Department of Neuropathology, Oregon Health & Science University, Portland, OR, United States
| | - Anusha Mishra
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, United States.
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Neural Vascular Mechanism for the Cerebral Blood Flow Autoregulation after Hemorrhagic Stroke. Neural Plast 2017; 2017:5819514. [PMID: 29104807 PMCID: PMC5634612 DOI: 10.1155/2017/5819514] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 09/11/2017] [Indexed: 12/21/2022] Open
Abstract
During the initial stages of hemorrhagic stroke, including intracerebral hemorrhage and subarachnoid hemorrhage, the reflex mechanisms are activated to protect cerebral perfusion, but secondary dysfunction of cerebral flow autoregulation will eventually reduce global cerebral blood flow and the delivery of metabolic substrates, leading to generalized cerebral ischemia, hypoxia, and ultimately, neuronal cell death. Cerebral blood flow is controlled by various regulatory mechanisms, including prevailing arterial pressure, intracranial pressure, arterial blood gases, neural activity, and metabolic demand. Evoked by the concept of vascular neural network, the unveiled neural vascular mechanism gains more and more attentions. Astrocyte, neuron, pericyte, endothelium, and so forth are formed as a communicate network to regulate with each other as well as the cerebral blood flow. However, the signaling molecules responsible for this communication between these new players and blood vessels are yet to be definitively confirmed. Recent evidence suggested the pivotal role of transcriptional mechanism, including but not limited to miRNA, lncRNA, exosome, and so forth, for the cerebral blood flow autoregulation. In the present review, we sought to summarize the hemodynamic changes and underline neural vascular mechanism for cerebral blood flow autoregulation in stroke-prone state and after hemorrhagic stroke and hopefully provide more systematic and innovative research interests for the pathophysiology and therapeutic strategies of hemorrhagic stroke.
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Terpolilli NA, Brem C, Bühler D, Plesnila N. Are We Barking Up the Wrong Vessels? Stroke 2015; 46:3014-9. [DOI: 10.1161/strokeaha.115.006353] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 05/21/2015] [Indexed: 12/31/2022]
Affiliation(s)
- Nicole Angela Terpolilli
- From the Department of Neurosurgery (N.A.T.), Department of Neuroradiology (C.B.), Institute for Stroke and Dementia Research (D.B., N.P.), and Munich Cluster for Systems Neurology (SyNergy) (N.P.), University of Munich Medical Center, Munich, Germany
| | - Christian Brem
- From the Department of Neurosurgery (N.A.T.), Department of Neuroradiology (C.B.), Institute for Stroke and Dementia Research (D.B., N.P.), and Munich Cluster for Systems Neurology (SyNergy) (N.P.), University of Munich Medical Center, Munich, Germany
| | - Dominik Bühler
- From the Department of Neurosurgery (N.A.T.), Department of Neuroradiology (C.B.), Institute for Stroke and Dementia Research (D.B., N.P.), and Munich Cluster for Systems Neurology (SyNergy) (N.P.), University of Munich Medical Center, Munich, Germany
| | - Nikolaus Plesnila
- From the Department of Neurosurgery (N.A.T.), Department of Neuroradiology (C.B.), Institute for Stroke and Dementia Research (D.B., N.P.), and Munich Cluster for Systems Neurology (SyNergy) (N.P.), University of Munich Medical Center, Munich, Germany
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The evolving roles of pericyte in early brain injury after subarachnoid hemorrhage. Brain Res 2015; 1623:110-22. [PMID: 25982598 DOI: 10.1016/j.brainres.2015.05.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Revised: 05/02/2015] [Accepted: 05/04/2015] [Indexed: 12/21/2022]
Abstract
Despite accumulated understanding on the mechanisms of early brain injury and improved management of subarachnoid hemorrhage (SAH), it is still one of the serious and refractory health problems around the world. Traditionally, pericyte, served as capillary contraction handler, is recently considered as the main participant of microcirculation regulation in SAH pathophysiology. However, accumulate evidences indicate that pericyte is much more than we already know. Therefore, we briefly review the characteristics, regulation pathways and functions of pericyte, aim to summarize the evolving new pathophysiological roles of pericyte that are implicated in early brain injury after SAH and to improve our understanding in order to explore potential novel therapeutic options for patients with SAH. This article is part of a Special Issue entitled SI: Cell Interactions In Stroke.
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Pathological mechanisms underlying aneurysmal subarachnoid haemorrhage and vasospasmElsevier Ltd. J Clin Neurosci 2015; 22:1-5. [DOI: 10.1016/j.jocn.2014.05.025] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 04/27/2014] [Accepted: 05/04/2014] [Indexed: 11/18/2022]
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Kikkawa Y, Kurogi R, Sasaki T. The single and double blood injection rabbit subarachnoid hemorrhage model. Transl Stroke Res 2014; 6:88-97. [PMID: 25381219 DOI: 10.1007/s12975-014-0375-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 09/25/2014] [Accepted: 10/22/2014] [Indexed: 12/27/2022]
Abstract
Over the past 30 years, the rabbit subarachnoid hemorrhage model (SAH) has been used for investigating the post-hemorrhage pathology, especially with respect to understanding of the mechanisms of cerebral vasospasm. However, the molecular mechanisms of cerebral vasospasm remain to be elucidated. Furthermore, it is not clear whether the rabbit SAH model is suitable for the investigation of pathological conditions other than cerebral vasospasm, such as early brain injury. Therefore, the properties of the rabbit SAH model need to be validated, and the reasons for using the rabbit should be clarified. This review explores the settings and technical issues of establishing a rabbit cisterna magna single and double blood injection SAH model and discusses the characteristics and feasibilities of the models.
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Affiliation(s)
- Yuichiro Kikkawa
- Department of Neurosurgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan,
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10
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Zhang JH. Vascular neural network in subarachnoid hemorrhage. Transl Stroke Res 2014; 5:423-8. [PMID: 24986148 DOI: 10.1007/s12975-014-0355-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 06/19/2014] [Indexed: 02/06/2023]
Affiliation(s)
- John H Zhang
- Department of Neurosurgery, Loma Linda University School of Medicine, Loma Linda, CA, 92350, USA,
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11
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Subarachnoid Hemorrhage: a Review of Experimental Studies on the Microcirculation and the Neurovascular Unit. Transl Stroke Res 2014; 5:174-89. [DOI: 10.1007/s12975-014-0323-4] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 12/20/2013] [Accepted: 01/03/2014] [Indexed: 11/29/2022]
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12
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Westermaier T, Stetter C, Raslan F, Vince GH, Ernestus RI. Brain edema formation correlates with perfusion deficit during the first six hours after experimental subarachnoid hemorrhage in rats. EXPERIMENTAL & TRANSLATIONAL STROKE MEDICINE 2012; 4:8. [PMID: 22551223 PMCID: PMC3398845 DOI: 10.1186/2040-7378-4-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2011] [Accepted: 05/02/2012] [Indexed: 11/23/2022]
Abstract
Background Severe brain edema is observed in a number of patients suffering from subarachnoid hemorrhage (SAH). Little is known about its pathogenesis and time-course in the first hours after SAH. This study was performed to investigate the development of brain edema and its correlation with brain perfusion after experimental SAH. Methods Male Sprague–Dawley rats, randomly assigned to one of six groups (n = 8), were subjected to SAH using the endovascular filament model or underwent a sham operation. Animals were sacrificed 15, 30, 60, 180 or 360 minutes after SAH. Intracranial pressure (ICP), mean arterial blood pressure (MABP), cerebral perfusion pressure (CPP) and bilateral local cerebral blood flow (LCBF) were continuously measured. Brain water content (BWC) was determined by the wet/dry-weight method. Results After SAH, CPP and LCBF rapidly decreased. The decline of LCBF markedly exceeded the decline of CPP and persisted until the end of the observation period. BWC continuously increased. A significant correlation was observed between the BWC and the extent of the perfusion deficit in animals sacrificed after 180 and 360 minutes. Conclusions The significant correlation with the perfusion deficit after SAH suggests that the development of brain edema is related to the extent of ischemia and acute vasoconstriction in the first hours after SAH.
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Affiliation(s)
- Thomas Westermaier
- Department of Neurosurgery, University of Würzburg, Josef-Schneider-Str, 11, Würzburg, 97080, Germany.
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Zhuang Z, Zhou ML, You WC, Zhu L, Ma CY, Sun XJ, Shi JX. Hydrogen-rich saline alleviates early brain injury via reducing oxidative stress and brain edema following experimental subarachnoid hemorrhage in rabbits. BMC Neurosci 2012; 13:47. [PMID: 22587664 PMCID: PMC3436733 DOI: 10.1186/1471-2202-13-47] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2011] [Accepted: 04/10/2012] [Indexed: 12/31/2022] Open
Abstract
Background Increasing experimental and clinical data indicate that early brain injury (EBI) after subarachnoid hemorrhage (SAH) largely contributes to unfavorable outcomes, and it has been proved that EBI following SAH is closely associated with oxidative stress and brain edema. The present study aimed to examine the effect of hydrogen, a mild and selective cytotoxic oxygen radical scavenger, on oxidative stress injury, brain edema and neurology outcome following experimental SAH in rabbits. Results The level of MDA, caspase-12/3 and brain water content increased significantly at 72 hours after experimental SAH. Correspondingly, obvious brain injury was found in the SAH group by terminal deoxynucleotidyl transferase-mediated uridine 5’-triphosphate-biotin nick end-labeling (TUNEL) and Nissl staining. Similar results were found in the SAH + saline group. In contrast, the upregulated level of MDA, caspase-12/3 and brain edema was attenuated and the brain injury was substantially alleviated in the hydrogen treated rabbits, but the improvement of neurology outcome was not obvious. Conclusion The results suggest that treatment with hydrogen in experimental SAH rabbits could alleviate brain injury via decreasing the oxidative stress injury and brain edema. Hence, we conclude that hydrogen possesses the potential to be a novel therapeutic agent for EBI after SAH.
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Affiliation(s)
- Zong Zhuang
- Department of Neurosurgery, Jinling Hospital, School of Medicine, Nanjing University, 305 East Zhongshan Road, Nanjing, 210002, Jiangsu Province, China
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Thal SC, Sporer S, Klopotowski M, Thal SE, Woitzik J, Schmid-Elsaesser R, Plesnila N, Zausinger S. Brain edema formation and neurological impairment after subarachnoid hemorrhage in rats. J Neurosurg 2009; 111:988-94. [DOI: 10.3171/2009.3.jns08412] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
Global cerebral edema is an independent risk factor for early death and poor outcome after subarachnoid hemorrhage (SAH). In the present study, the time course of brain edema formation, neurological deficits, and neuronal cell loss were investigated in the rat filament SAH model.
Methods
Brain water content and neurological deficits were determined in rats randomized to sham (1-, 24-, or 48-hour survival), SAH by endovascular perforation (1-, 24-, or 48-hour survival), or no surgery (control). The neuronal cell count (CA1–3) was quantified in a separate set of SAH (6-, 24-, 48-, or 72-hour survival) and shamoperated animals.
Results
Brain water content increased significantly 24 (80.2 ± 0.4% [SAH] vs 79.2 ± 0.1% [sham]) and 48 hours (79.8 ± 0.2% [SAH] vs 79.3 ± 0.1% [sham]) after SAH. The neuroscore was significantly worse after SAH (33 ± 15 [24 hours after SAH] vs 0 ± 0 points [sham]) and correlated with the extent of brain edema formation (r = 0.96, p < 0.001). No hippocampal damage was present up to 72 hours after SAH.
Conclusions
Brain water content and neurological dysfunction reached a maximum at 24 hours after SAH. This time point, therefore, seems to be optimal to test the effects of therapeutic interventions on brain edema formation. Neuronal cell loss was not present in CA1–3 up to 72 hours of SAH. Therefore, morphological damage needs to be evaluated at later time points.
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Affiliation(s)
| | | | - Mariusz Klopotowski
- 4First Department of Coronary Artery Disease, Institute of Cardiology, Warsaw, Poland
| | | | - Johannes Woitzik
- 3Center of Stroke Research Berlin, and Department of Neurosurgery, Charité—Univeristätsmedizin Berlin, Germany; and
| | | | - Nikolaus Plesnila
- 1Institute for Surgical Research,
- 2Department of Neurosurgery, University of Munich Medical Center–Grosshadern, Munich
| | - Stefan Zausinger
- 2Department of Neurosurgery, University of Munich Medical Center–Grosshadern, Munich
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Thal SC, Sporer S, Schmid-Elsaesser R, Plesnila N, Zausinger S. Inhibition of bradykinin B2 receptors before, not after onset of experimental subarachnoid hemorrhage prevents brain edema formation and improves functional outcome. Crit Care Med 2009; 37:2228-34. [DOI: 10.1097/ccm.0b013e3181a068fc] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Ishikawa M, Kusaka G, Yamaguchi N, Sekizuka E, Nakadate H, Minamitani H, Shinoda S, Watanabe E. PLATELET AND LEUKOCYTE ADHESION IN THE MICROVASCULATURE AT THE CEREBRAL SURFACE IMMEDIATELY AFTER SUBARACHNOID HEMORRHAGE. Neurosurgery 2009; 64:546-53; discussion 553-4. [DOI: 10.1227/01.neu.0000337579.05110.f4] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Mami Ishikawa
- Department of Neurosurgery, Saitama Medical Center, Jichi Medical University, Saitama, Japan
| | - Gen Kusaka
- Department of Neurosurgery, Saitama Medical Center, Jichi Medical University, Saitama, Japan
| | - Noriyuki Yamaguchi
- Department of Neurosurgery, National Hospital Organization, Saitama Hospital, Saitama, Japan
| | - Eiichi Sekizuka
- Department of Internal Medicine, National Hospital Organization, Saitama Hospital, Saitama, Japan
| | - Hiromichi Nakadate
- Graduate School of Science and Technology, Keio University, Tokyo, Japan
| | | | - Soji Shinoda
- Department of Neurosurgery, Saitama Medical Center, Jichi Medical University, Saitama, Japan
| | - Eiju Watanabe
- Department of Neurosurgery, Jichi Medical University, Tochigi, Japan
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Niikawa S, Yasokawa Y, Ito T. Development of early cerebral swelling in surgically treated ruptured aneurysm of acute stage, its significance, and management. J Stroke Cerebrovasc Dis 2008; 14:58-66. [PMID: 17904002 DOI: 10.1016/j.jstrokecerebrovasdis.2004.12.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2004] [Revised: 11/15/2004] [Accepted: 11/22/2004] [Indexed: 10/25/2022] Open
Abstract
The present study includes 38 patients treated surgically for ruptured aneurysm manifesting subarachnoid hemorrhage without intracerebral hematoma, evaluating clinical grade at admission, secondary development and management of early cerebral swelling, subsequent complications such as cerebral infarction caused by vasospasm, and clinical outcome. Six of 32 patients treated by early surgery within 24 hours developed critical cerebral swelling in the early period after SAH. Five of these 6 patients received barbiturate therapy. Two patients died of advancing cerebral swelling. Three of 5 patients who received barbiturate therapy showed good recovery without any neurologic deficit, 1 suffered intellectual impairment, and the other 1 died. Serial computed tomography (CT), CT angiography, and dynamic CT evaluated elapsing of cerebral swelling, progression of cerebral vasospasm, and change of cerebral blood perfusion (flow) in 2 patients who suffered early cerebral swelling. In these 2 patients, progression or persistence of vasospasm was recorded for a longer period, whereas the cerebral swelling resolved within a short period. Cerebral infarction caused by vasospasm was seen in 8 of these 38 surgical cases, and hydrocephalus was seen in 15 of 38 cases. All 4 survivors after early cerebral swelling developed hydrocephalus and underwent shunting. Development of cerebral swelling in patients with ruptured aneurysm greatly affects outcome. Although barbiturate therapy is useful for the treatment of patients who suffer serious cerebral swelling, improvements in management may be required.
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Affiliation(s)
- Shuji Niikawa
- Department of Neurosurgery, Sumi Memorial Hospital, Gifu, Japan
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Mocco J, Prickett CS, Komotar RJ, Connolly ES, Mayer SA. Potential mechanisms and clinical significance of global cerebral edema following aneurysmal subarachnoid hemorrhage. Neurosurg Focus 2007; 22:E7. [PMID: 17613238 DOI: 10.3171/foc.2007.22.5.8] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
✓In an attempt to elucidate the pathophysiology and clinical significance of global cerebral edema (GCE) following aneurysmal subarachnoid hemorrhage (SAH), the authors explored potential mechanisms and reviewed findings associated with this phenomenon. Admission computed tomography (CT) scans show GCE in up to 20% of patients experiencing aneurysmal SAH. This edema is likely to have been initiated by transient global ischemia, as indicated by an association between ictal loss of consciousness and the development of edema. A further cascade of events, including a rise in intracranial pressure and compromise of the blood–brain barrier, are also likely contributors. Clinically, GCE on CT after aneurysmal SAH is predictive of a poor outcome. Further investigation is needed to gain a full understanding of edema development following SAH, with the hope that the knowledge can be used to influence treatment positively and improve outcome.
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Affiliation(s)
- J Mocco
- Department of Neurosurgery, Columbia University, New York, New York 10032, USA.
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Schöller K, Trinkl A, Klopotowski M, Thal SC, Plesnila N, Trabold R, Hamann GF, Schmid-Elsaesser R, Zausinger S. Characterization of microvascular basal lamina damage and blood-brain barrier dysfunction following subarachnoid hemorrhage in rats. Brain Res 2007; 1142:237-46. [PMID: 17303089 DOI: 10.1016/j.brainres.2007.01.034] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2006] [Revised: 01/11/2007] [Accepted: 01/11/2007] [Indexed: 10/23/2022]
Abstract
Vasogenic brain edema is one of the major determinants for mortality following subarachnoid hemorrhage (SAH). Although the formation of vasogenic brain edema occurs on the microvascular level by opening of endothelial tight junctions and disruption of the basal lamina, microvascular changes following experimental SAH are poorly characterized. The aim of the present study was therefore to investigate the time course of blood-brain barrier (BBB) dysfunction and basal lamina damage following SAH as a basis for the better understanding of the pathophysiology of SAH. SAH was induced in Sprague-Dawley rats by an endovascular filament. Animals were sacrificed 6, 24, 48, and 72 h thereafter (n=9 per group). Microvascular basal lamina damage was quantified by collagen type IV immunostaining. Western blotting was used to quantify collagen IV protein content and bovine serum albumin (BSA) extravasation as a measure for basal lamina damage and blood-brain barrier disruption, respectively. BSA Western blot revealed significant (p<0.05) BBB opening in the cerebral cortex ipsilateral to the hemorrhage beginning 6 h and peaking 48 h after SAH. Significant (p<0.05) basal lamina damage occurred with gradual increase from 24 to 72 h. Basal lamina damage correlated significantly with BBB dysfunction (r=-0.63; p=0.0001). Microvascular damage as documented by collagen IV degradation and albumin extravasation is a long lasting and ongoing process following SAH. Due to its delayed manner microvascular damage may be prone for therapeutic interventions. However, further investigations are needed to determine the molecular mechanisms responsible for basal lamina degradation and hence damage of the microvasculature following SAH.
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Affiliation(s)
- Karsten Schöller
- Department of Neurosurgery, University of Munich Medical Center-Grosshadern, Ludwig-Maximilians-University, Munich, Germany
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20
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Ostrowski RP, Colohan AR, Zhang JH. Molecular mechanisms of early brain injury after subarachnoid hemorrhage. Neurol Res 2006; 28:399-414. [PMID: 16759443 DOI: 10.1179/016164106x115008] [Citation(s) in RCA: 204] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
OBJECTIVES Increasing body of experimental and clinical data indicates that early brain injury after initial bleeding largely contributes to unfavorable outcome after subarachnoid hemorrhage (SAH). This review presents molecular mechanisms underlying brain injury at its early stages after SAH. METHODS PubMed was searched using term 'subarachnoid hemorrhage' and key words referring to molecular and cellular pathomechanisms of SAH-induced early brain injury. RESULTS The authors reviewed intracranial phenomena and molecular agents that contribute to the early development of pathological sequelae of SAH in cerebral and vascular tissues, including cerebral ischemia and its interactions with injurious blood components, blood-brain barrier disruption, brain edema and apoptosis. DISCUSSION It is believed that detailed knowledge of molecular signaling pathways after SAH will serve to improve therapeutic interventions. The most promising approach is the protection of neurovascular unit including anti-apoptosis therapy.
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21
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Bermueller C, Thal SC, Plesnila N, Schmid-Elsaesser R, Kreimeier U, Zausinger S. Hypertonic fluid resuscitation from subarachnoid hemorrhage in rats: A comparison between small volume resuscitation and mannitol. J Neurol Sci 2006; 241:73-82. [PMID: 16343544 DOI: 10.1016/j.jns.2005.10.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2005] [Revised: 10/21/2005] [Accepted: 10/24/2005] [Indexed: 10/25/2022]
Abstract
OBJECTIVE Death and severe morbidity after subarachnoid hemorrhage (SAH) are mainly caused by global cerebral ischemia through increased intracranial pressure (ICP) and decreased cerebral blood flow (CBF). We have recently demonstrated neuroprotective effects of small volume resuscitation (7.5% saline in combination with 6% dextran 70) in an animal model of SAH, leading to normalization of increased ICP, reduced morphological damage and improved neurological recovery. In the present study, we compared the concept of small volume resuscitation represented by two clinically licenced hypertonic-hyperoncotic saline solutions with the routinely used hyperosmotic agent-mannitol-and investigated their effects on ICP, CBF, neurological recovery and morphological damage after SAH in rats. METHODS 60 dextran-resistant Wistar rats were subjected to SAH by an endovascular filament. ICP, MABP (mean arterial blood pressure) and bilateral local CBF were continuously recorded. All animals were randomly assigned to four groups: (I) NaCl 0.9% (4 ml/kg bw), (II) 7.5% NaCl+6% dextran 70 (4 ml/kg bw), (III) 7.2% NaCl+HES 200,000 (4 ml/kg bw) and (IV) 20% mannitol (9.33 ml/kg bw) given 30 min after SAH. Neurological deficits were assessed on days 1, 3 and 7 after SAH. The morphological damage was evaluated on day 7 after SAH. RESULTS The induction of SAH resulted in an immediate ICP increase to 46.6+/-3.2 mm Hg (mean+/-S.E.M.) and 29.6+/-1.3 (mean+/-S.E.M.) mm Hg 90 min post-SAH. While a treatment with both hypertonic saline solutions (II, III) decreased ICP as well as the 20% mannitol solution, only the group treated with hypertonic saline and dextran 70 (II) showed an increase of ipsilateral CBF for 20 min after the infusion and significantly more surviving neurons in the motorcortex and caudoputamen. Mortality was reduced from 60% (I) and 73% (III and IV), respectively, to 40% in group II. CONCLUSION Of all hypertonic solutions investigated, small volume resuscitation with NaCl 7.5% in combination with 6% dextran 70 evolved to be most effective in terms of reducing the initial harmful sequelae of SAH, leading to lowered ICP and less morphological damage after SAH in the rat.
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Affiliation(s)
- Christian Bermueller
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Ulm, D-89070 Ulm, Germany.
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22
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Sehba FA, Mostafa G, Friedrich V, Bederson JB. Acute microvascular platelet aggregation after subarachnoid hemorrhage. J Neurosurg 2005; 102:1094-100. [PMID: 16028769 DOI: 10.3171/jns.2005.102.6.1094] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT The mechanisms underlying acute cerebral ischemia after subarachnoid hemorrhage (SAH) are not well established. Platelets aggregate within major cerebral vessels hours after SAH, but this has not been studied in the microvasculature. Platelet aggregates within the microvasculature could mechanically obstruct the lumen and initiate events that injure vessel structure. In the present study the authors examined the hypothesis that platelets aggregate within the cerebral microvasculature acutely after SAH. METHODS Subarachnoid hemorrhage was induced in the rat by using the endovascular perforation model. The animals were killed between 10 minutes and 48 hours after SAH. Immunostaining for the platelet surface receptor glycoprotein (GP)IIb/IIIa, which mediates platelet aggregation, was used to detect platelet aggregation. Sham-operated animals were used as controls. The GPIIb/IIIa immunoreactive platelet aggregates were abundant in the microvasculature of the basal and frontal cortex, striatum, and hippocampus 10 minutes after SAH. These aggregates decreased in number from 1 to 6 hours post-SAH and then increased to a peak at 24 hours. No immunoreactive aggregates were observed 48 hours after SAH. CONCLUSIONS The data indicate that widespread platelet aggregation occurs very rapidly in response to SAH followed by a decrease within 6 hours and a subsequent increase 24 hours after SAH. Microvascular platelet aggregates may contribute to decreased cerebral blood flow and ischemic injury after SAH via a number of mechanisms.
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Affiliation(s)
- Fatima A Sehba
- Department of Neurosurgery, Mount Sinai School of Medicine, New York, New York 10029-6574, USA.
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23
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Harrod CG, Bendok BR, Batjer HH. Prediction of Cerebral Vasospasm in Patients Presenting with Aneurysmal Subarachnoid Hemorrhage: A Review. Neurosurgery 2005; 56:633-54; discussion 633-54. [PMID: 15792502 DOI: 10.1227/01.neu.0000156644.45384.92] [Citation(s) in RCA: 157] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2004] [Accepted: 01/07/2005] [Indexed: 12/20/2022] Open
Abstract
Abstract
OBJECTIVE:
Cerebral vasospasm is a devastating medical complication of aneurysmal subarachnoid hemorrhage (SAH). It is associated with high morbidity and mortality rates, even after the aneurysm has been treated. A substantial amount of experimental and clinical research has been conducted in an effort to predict and prevent its occurrence. This research has contributed to significant advances in the understanding of the mechanisms leading to cerebral vasospasm. The ability to accurately and consistently predict the onset of cerebral vasospasm, however, has been challenging. This topic review describes the various methodologies and approaches that have been studied in an effort to predict the occurrence of cerebral vasospasm in patients presenting with SAH.
METHODS:
The English-language literature on the prediction of cerebral vasospasm after aneurysmal SAH was reviewed using the MEDLINE PubMed (1966–present) database.
RESULTS:
The risk factors, diagnostic imaging, bedside monitoring approaches, and pathological markers that have been evaluated to predict the occurrence of cerebral vasospasm after SAH are presented.
CONCLUSION:
To date, a large blood burden is the only consistently demonstrated risk factor for the prediction of cerebral vasospasm after SAH. Because vasospasm is such a multifactorial problem, attempts to predict its occurrence will probably require several different approaches and methodologies, as is done at present. Future improvements in the prevention of cerebral vasospasm from aneurysmal SAH will most likely require advances in our understanding of its pathophysiology and our ability to predict its onset.
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Affiliation(s)
- Christopher G Harrod
- Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA.
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24
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Sehba FA, Mostafa G, Knopman J, Friedrich V, Bederson JB. Acute alterations in microvascular basal lamina after subarachnoid hemorrhage. J Neurosurg 2004; 101:633-40. [PMID: 15481718 DOI: 10.3171/jns.2004.101.4.0633] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object. Aneurysmal subarachnoid hemorrhage (SAH) causes acute and delayed ischemic brain injuries. The mechanisms of acute ischemic injury following SAH are poorly understood, although an acute increase in microvascular permeability has been noted. The integrity of cerebral microvessels is maintained in part by components of basal lamina: collagen IV, elastin, lamina, and so forth. Destruction of basal lamina components by collagenases and matrix metalloproteinases (MMPs), especially MMP-9, has been known to occur in other ischemic models. The authors assessed the integrity of cerebral microvasculature after acute SAH by examining collagen IV and MMP-9 levels and collagenase activity in the microvessels.
Methods. Subarachnoid hemorrhage was induced in rats through endovascular perforation of the intracranial bifurcation of the internal carotid artery. Animals were killed 10 minutes to 48 hours after SAH or sham operation (time-matched controls). Levels of collagen IV and MMP-9 were studied in the microvasculature by performing immunoperoxidase and immunofluorescence staining, and collagenase activity was assessed by in situ zymography.
Little change occurred in collagen IV and MMP-9 immunostaining or collagenase activity at 10 minutes or 1 hour after SAH. Starting 3 hours after SAH, collagen IV immunostaining was reduced or eliminated along segments of microvessels whereas MMP-9 staining was segmentally increased. These effects reached a maximum at 6 hours and returned toward those values in sham-operated controls at 48 hours.
Conclusions. Results of this study demonstrated an acute loss of collagen IV from the cerebral microvasculature after SAH and indicated that MMP-9 contributes to this event. The loss of collagen IV might contribute to the known failure of the blood—brain barrier after SAH.
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Affiliation(s)
- Fatima A Sehba
- Departments of Neurosurgery and Neurobiology, Mount Sinai School of Medicine, New York, New York 10029-6574, USA.
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25
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Zausinger S, Thal SC, Kreimeier U, Messmer K, Schmid-Elsaesser R. Hypertonic Fluid Resuscitation from Subarachnoid Hemorrhage in Rats. Neurosurgery 2004; 55:679-86; discussion 686-7. [PMID: 15335436 DOI: 10.1227/01.neu.0000134558.28977.ee] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2003] [Accepted: 02/24/2004] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE Increased intracranial pressure (ICP) and decreased cerebral blood flow leading to global cerebral ischemia are the primary causes of death after severe subarachnoid hemorrhage (SAH). Hypertonic saline has been demonstrated to exert neuroprotective properties after traumatic brain injury by osmotic mobilization of parenchymal water and improvement of microcirculation. We used a rat model to investigate the effects of hypertonic fluid resuscitation after SAH on ICP, cerebral blood flow, body weight, neurological recovery, and morphological damage. METHODS Sixty rats were subjected to SAH induced by an endovascular filament. ICP and local cerebral blood flow were recorded continuously. Animals were assigned to three groups: 1) NaCl 0.9%; 2) NaCl 7.5% (4 ml/kg); and 3) NaCl 7.5% plus 6% dextran 70 (4 ml/kg) given 30 minutes after SAH. Body weight and neurological deficits were assessed daily. Morphological damage was evaluated on Day 7. RESULTS SAH resulted in an immediate increase of ICP to approximately 60 mm Hg initially, and then to approximately 30 mm Hg for the next 90 minutes. Although NaCl 7.5% alone and in combination with dextran led to an immediate, significant, and lasting decrease of ICP to 15 to 20 mm Hg, only the combined therapy significantly increased body weight and improved neurological recovery. Furthermore, the group that received combined therapy exhibited significantly more surviving neurons in hippocampus, cortex, caudoputamen, and cerebellum. Mortality was reduced nonsignificantly, from approximately 65% in groups I and II to 35% in Group III. CONCLUSION Treatment with NaCl 7.5% plus 6% dextran 70 is significantly effective for reducing the initial harmful sequelae of SAH. The regimen resulted in lowered ICP, improved neurological recovery, and less morphological damage after SAH in the rat.
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Affiliation(s)
- Stefan Zausinger
- Department of Neurosurgery, Ludwig-Maximilians-Universität, Klinikum Grosshadern, Munich, Germany.
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26
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Niesen WD, Rosenkranz M, Schummer W, Weiller C, Sliwka U. Cerebral Venous Flow Velocity Predicts Poor Outcome in Subarachnoid Hemorrhage. Stroke 2004; 35:1873-8. [PMID: 15178822 DOI: 10.1161/01.str.0000132195.17366.2b] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background and Purpose—
Predictors of clinical outcome in aneurysmal subarachnoid hemorrhage (SAH) vary in reliability. Measurement of cerebral venous hemodynamics by transcranial color-coded duplexsonography (TCCS) has become of increasing interest lately, and correlation with intracranial pressure (ICP) seems to be high. The aim of the presented study was to assess changes of cerebral venous hemodynamics in SAH and evaluate its relationship with clinical outcome.
Methods—
We performed sequential TCCS of venous peak flow velocities (vp-FVs) in the transversal sinus in 28 consecutive patients with aneurysmal SAH (Hunt and Hess scale 1 to 5). Measurement was initiated at onset of arterial vasospasm up to 5 days after SAH. All patients had a continuous ICP monitoring. Clinical outcome was evaluated with the modified ranking scale (MRS) 30 days after SAH. Patients were divided according to outcome: group I good recovery (MRS 0-III) and group II poor outcome (death or MRS IV-V). Maximum vp-FV, time-averaged vp-FV (mv-FV), and ICP were compared between groups.
Results—
Vp-FV and mv-FV as well as ICP of group II exceeded values of group I (
P
<0.001 for all 3 parameters). Vp-FV showed a positive correlation with ICP (
r
=0.63;
P
<0.001). A vp-FV exceeding 35.4 cm/s (sensitivity 100%; specificity 90.9%), an mv-FV exceeding 27.3 cm/s (sensitivity 94.1%; specificity 81.8%), and an ICP exceeding 24 mm Hg (sensitivity 87.5%; specificity 81.8%) predicted poor outcome (receiver operating characteristic analysis).
Conclusions—
Increased ICP values correlate with increased venous flow velocities. In SAH, increased ICP and increased venous flow velocities are associated with poor outcome. Flow velocity of the transversal sinus is a highly sensitive, reliable, and early predictor of outcome in SAH.
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Affiliation(s)
- Wolf-Dirk Niesen
- Department of Neurology, Universitätsklinikum Eppendorf, Hamburg, Germany.
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27
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Kusaka G, Ishikawa M, Nanda A, Granger DN, Zhang JH. Signaling pathways for early brain injury after subarachnoid hemorrhage. J Cereb Blood Flow Metab 2004; 24:916-25. [PMID: 15362722 DOI: 10.1097/01.wcb.0000125886.48838.7e] [Citation(s) in RCA: 245] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Few studies have examined the signaling pathways that contribute to early brain injury after subarachnoid hemorrhage (SAH). Using a rat SAH model, the authors explored the role of vascular endothelial growth factor (VEGF) and mitogen-activation protein kinase (MAPK) in early brain injury. Male Sprague-Dawley rats (n = 172) weighing 300 to 350 g were used for the experimental SAH model, which was induced by puncturing the bifurcation of the left anterior cerebral and middle cerebral arteries. The blood-brain barrier (BBB), brain edema, intracranial pressure, and mortality were evaluated at 24 hours after SAH. The phosphorylation of VEGF and different MAPK subgroups (ERK1/2, p38, and JNK) were examined in both the cortex and the major cerebral arteries. Experimental SAH increased intracranial pressure, BBB permeability, and brain edema and produced high mortality. SAH induced phosphorylation of VEGF and MAPKs in the cerebral arteries and, to a lesser degree, in the cortex. PP1, an Src-family kinase inhibitor, reduced BBB permeability, brain edema, and mortality and decreased the phosphorylation of VEGF and MAPKs. The authors conclude that VEGF contributes to early brain injury after SAH by enhancing the activation of the MAPK pathways, and that the inhibition of these pathways might offer new treatment strategies for SAH.
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Affiliation(s)
- Gen Kusaka
- Department of Neurosurgery, Louisiana State University Health Sciences Center in Shreveport, Shreveport, Louisiana 71130-3932, USA
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Perkins E, Kimura H, Parent AD, Zhang JH. Evaluation of the microvasculature and cerebral ischemia after experimental subarachnoid hemorrhage in dogs. J Neurosurg 2002; 97:896-904. [PMID: 12405379 DOI: 10.3171/jns.2002.97.4.0896] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
OBJECT Whether cerebral vasospasm occurs only in surface vessels or also in parenchymal arterioles is debatable. The present study was undertaken to evaluate comprehensively the microvasculature of the brainstem after experimental subarachnoid hemorrhage (SAH). METHODS Nine mongrel dogs of either sex, each weighing between 18 and 24 kg, underwent double blood injections spaced 48 hours apart; the injections were infused into the cisterna magna immediately after angiography of the basilar arteries (BAs). Three additional dogs assigned to a control group received no blood injections. The dogs were killed on Day 7. Axial sections obtained from the midpontine region of both control dogs and animals subjected to SAH were evaluated with respect to the morphological characteristics of vessels and neurons, and for ultrastructural changes. Severe vasospasm occurred in the BAs of all dogs subjected to SAH. Nevertheless, in these animals, the luminal areas and vessel perimeter in parenchymal arterioles, but not in parenchymal venules, were observed to have increased when compared with those of control dogs (p < 0.01, t-test). No corrugation of the internal elastic lamina was observed and smooth-muscle and endothelial cells remained normal at the ultrastructural level in the dogs with SAH. CONCLUSIONS In this model, vasospasm of the BAs did not extend into the region of the pons to affect the intraparenchymal arterioles. Dilation of the parenchymal arterioles might serve as compensation for reduced blood flow. Thus, no neuronal ischemia or infarction resulted in the pontine region of the brain.
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Affiliation(s)
- Eddie Perkins
- Department of Neurosurgery, University of Mississippi Medical Center, Jackson, USA
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29
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Jabre A, Babikian V, Powsner RA, Spatz EL. Role of single photon emission computed tomography and transcranial Doppler ultrasonography in clinical vasospasm. J Clin Neurosci 2002; 9:400-3. [PMID: 12217668 DOI: 10.1054/jocn.2002.1007] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This report presents our experience with Transcranial Doppler (TCD) ultrasonography and Single Photon Emission Computed Tomography (SPECT) in the assessment of patients with aneurysmal subarachnoid haemorrhage (SAH). It was designed to evaluate clinical vasospasm with both TCD and SPECT and determine their diagnostic value. Twenty-eight consecutive patients were examined with both TCD and SPECT, performed within 24 hours of each other. They had a total of 45 TCDs and 46 SPECT scans. Eight patients (29%) developed clinical vasospasm, noted from day 2 to day 11 post subarachnoid haemorrhage; these patients underwent TCDs and SPECT scans when the diagnosis of vasospasm was made. Twenty patients (71%) did not demonstrate clinical vasospasm throughout their hospital stay and underwent TCDs and SPECT scans within the first 2 weeks of their SAH, mostly between day 2 and day 10, the period of greatest risk for vasospasm. TCD and SPECT sensitivity for clinical vasospasm was 100% and 50% respectively, their specificity was only 20% and 60%. TCD sensitivity for symptomatic vasospasm was found to be excellent, whereas SPECT was not found to be as useful. We conclude that TCD is the preferred method in the evaluation of patients with subarachnoid haemorrhage.
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Affiliation(s)
- Anthony Jabre
- Department of Neurosurgery, Boston University Medical Center, Boston, Massachusetts 02118, USA.
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30
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Claassen J, Carhuapoma JR, Kreiter KT, Du EY, Connolly ES, Mayer SA. Global cerebral edema after subarachnoid hemorrhage: frequency, predictors, and impact on outcome. Stroke 2002; 33:1225-32. [PMID: 11988595 DOI: 10.1161/01.str.0000015624.29071.1f] [Citation(s) in RCA: 391] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
BACKGROUND AND PURPOSE Cerebral edema visualized by CT is often seen after subarachnoid hemorrhage (SAH). Inflammatory or circulatory mechanisms have been postulated to explain this radiographic observation after SAH. We sought to determine the frequency, causes, and impact on outcome of early and delayed global cerebral edema after SAH. METHODS We evaluated the presence of global edema on admission and follow-up CT scans in 374 SAH patients admitted within 5 days of onset to our Neurological Intensive Care Unit between July 1996 and February 2001. Using multivariate analysis, we identified predictors of global cerebral edema and evaluated the impact of global edema on outcome 3 months after onset with the modified Rankin Scale. RESULTS Global edema was present on admission CT scans in 8% (n=29) and developed secondarily in 12% (n=44) of the patients. Global edema on admission was predicted by loss of consciousness at ictus and increasing Hunt-Hess grade. Delayed global edema was predicted by aneurysm size >10 mm, loss of consciousness at ictus, use of vasopressors, and increased SAH sum scores. Thirty-seven percent (n=137) of the patients were dead or severely disabled (modified Rankin Scale 4 to 6) at 3 months. Death or severe disability was predicted by any global edema, aneurysm size >10 mm, loss of consciousness at ictus, increased National Institutes of Health Stroke Scale scores, and older age. CONCLUSIONS Global edema is an independent risk factor for mortality and poor outcome after SAH. Loss of consciousness, which may reflect ictal cerebral circulatory arrest, is a risk factor for admission global edema, and vasopressor-induced hypertension is associated with the development of delayed global edema. Critical care management strategies that minimize edema formation after SAH may improve outcome.
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Affiliation(s)
- Jan Claassen
- Division of Critical Care Neurology, Department of Neurology, Columbia University College of Physicians and Surgeons, New York, NY, USA
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Kreiter KT, Copeland D, Bernardini GL, Bates JE, Peery S, Claassen J, Du YE, Stern Y, Connolly ES, Mayer SA. Predictors of cognitive dysfunction after subarachnoid hemorrhage. Stroke 2002; 33:200-8. [PMID: 11779911 DOI: 10.1161/hs0102.101080] [Citation(s) in RCA: 190] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Cognitive dysfunction is a common and disabling sequela of subarachnoid hemorrhage (SAH). Although several clinical and radiographic findings have been implicated in the pathogenesis of cognitive dysfunction after SAH, few prospective studies have comprehensively and simultaneously evaluated these risk factors. METHODS Between July 1996 and March 2000, we prospectively evaluated 113 of 248 consecutively admitted nontraumatic SAH patients alive at 3 months with a comprehensive neuropsychological evaluation. Summary scores for 8 cognitive domains were calculated to express test performance relative to the entire study population. Clinical and radiographic variables associated with domain-specific cognitive dysfunction were identified with forward stepwise multiple regression, with control for the influence of demographic factors. RESULTS The study participants were younger (P=0.005), less often white (P=0.006), and had better 3-month modified Rankin scores (P=0.001) than those who did not undergo neuropsychological testing. The proportion of subjects who scored in the impaired range (>2 SD below the normative mean) on each neuropsychological test ranged from 10% to 50%. Predictors of cognitive dysfunction in 2 or more domains in the multivariate analysis included global cerebral edema (4 domains), left-sided infarction (3 domains), and lack of a posterior circulation aneurysm (2 domains). Other variables consistently associated with cognitive dysfunction in the univariate analysis included admission Hunt-Hess grade >2 and thick SAH in the anterior interhemispheric and sylvian fissures. CONCLUSIONS Global cerebral edema and left-sided infarction are important risk factors for cognitive dysfunction after SAH. Treatment strategies aimed at reducing neurological injury related to generalized brain swelling, infarction, and clot-related hemotoxicity hold the best promise for improving cognitive outcomes after SAH.
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Ohkuma H, Itoh K, Shibata S, Suzuki S. Morphological changes of intraparenchymal arterioles after experimental subarachnoid hemorrhage in dogs. Neurosurgery 1997; 41:230-5; discussion 235-6. [PMID: 9218311 DOI: 10.1097/00006123-199707000-00036] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
OBJECTIVE Morphological and microcirculatory changes in intraparenchymal vessels after subarachnoid hemorrhage (SAH) have not yet been fully clarified. We conducted this experimental study to investigate the serial morphological changes of intraparenchymal arterioles after SAH. METHODS SAH was produced by injecting autologous arterial blood into the cisterna magna twice at 48-hour intervals in 30 dogs. The dogs were killed 3, 7, or 14 days after SAH, and then perfusion-fixed specimens of both anterior sylvian giri were obtained by using two methods. Microvascular corrosion casts produced by arterial injection of polyester resin were examined using scanning electron microscopy, and the widths of 40 arterioles of each animal were measured. Sectioned slices from the brain surface to 500 microns deep were examined by light microscopy, and external diameter, internal diameters, and wall thickness of the arterioles at depths of 50, 200, and 500 microns from the brain surface were morphometrically evaluated in 40 arterioles of each animal. In control animals receiving cisternal injections of mock cerebrospinal fluid (n = 10) and in healthy control animals (n = 10), the same examination and evaluation were performed. RESULTS Corrosion casts of arterioles showed tapered narrowing with folding after SAH, and the width of the arterioles significantly decreased 3 and 7 days after SAH (P < 0.01). Morphometric examination by light microscopy showed a significant decrease of internal diameter of arterioles associated with a significant increase of wall thickness at any depth from the brain surface 3 and 7 days after SAH (P < 0.05 or P < 0.01). These findings improved 14 days after SAH. Control animals receiving cisternal injections of mock cerebrospinal fluid showed no significant differences compared with healthy control animals. CONCLUSION These results suggest that constriction of intraparenchymal arterioles occurs after SAH and may contribute to delayed cerebral ischemia.
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Affiliation(s)
- H Ohkuma
- Department of Neurosurgery, Hirosaki University School of Medicine, Japan
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Piepgras A, Thomé C, Schmiedek P. Characterization of an anterior circulation rat subarachnoid hemorrhage model. Stroke 1995; 26:2347-52. [PMID: 7491662 DOI: 10.1161/01.str.26.12.2347] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
BACKGROUND AND PURPOSE Our aim was to demonstrate the feasibility of an angiographically controlled rat model for the study of macrocirculatory and microcirculatory changes of the anterior intracranial circulation after subarachnoid hemorrhage. METHODS Subarachnoid hemorrhage was induced by transorbital injection of 0.3 mL of nonheparinized autologous arterial blood into the chiasmatic cistern. Changes in regional cerebral blood flow were continuously recorded with the use of laser-Doppler flowmetry over the parietal cortex. Angiographic verification of middle cerebral artery diameter was performed by carotid catheterization at baseline and 2 days after injection of blood or artificial cerebrospinal fluid. We monitored intracranial and systemic blood pressure during and after injections. RESULTS Injection of artificial cerebrospinal fluid in the control group did not change the diameter of the middle cerebral artery. Injection of blood caused a significant arterial narrowing of 17.5%, from 0.37 +/- 0.04 mm to 0.31 +/- 0.04 mm after 2 days (P = .0001). In the control group regional cerebral blood flow decreased to 75.9 +/- 16.8% of preinjection control but quickly recovered to 99.7 +/- 19.4%. Intracranial pressure increased for 5 minutes after the injection to a maximum of 27.3 +/- 8.9 mm Hg, accompanied by a 10% decrease in mean arterial pressure. A fall in cerebral blood flow to 53.1 +/- 26.3% in blood-injected animals that recovered to only 80.7 +/- 16.9% of baseline values during the observation period of 30 minutes was noted. A peak intracranial pressure of 45.7 +/- 11.5 mm Hg occurred 2 minutes after injection with a decrease in mean arterial pressure of 13%, resulting in a markedly lower cerebral perfusion pressure than in the control group. CONCLUSIONS An angiographically controlled model of subarachnoid hemorrhage primarily involving the anterior circulation is feasible in the rat. The resulting narrowing of the middle cerebral artery reflects moderate vasospasm and will allow further microcirculatory studies with cranial windows.
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Affiliation(s)
- A Piepgras
- Department of Neurosurgery, Klinikum Mannheim, Ruprecht-Karls-Universität Heidelberg, Germany
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Kanaiwa H, Kuchiwaki H, Inao S, Sugita K. Changes in the cerebrocortical capillary network following venous sinus occlusion in cats. SURGICAL NEUROLOGY 1995; 44:172-9; discussion 179-80. [PMID: 7502208 DOI: 10.1016/0090-3019(95)00126-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
BACKGROUND Although the important protective effect of venous collateral pathways in sinus occlusion on parenchymal injury has been demonstrated in previous works, the vascular response in the capillary microcirculation itself after cerebral venous occlusion has not been fully elucidated. We examined the morphology of the capillary network after venous occlusion by relating stereologic morphometric parameters to changes in local cerebral blood flow and the development of brain edema. METHODS Experimental venous sinus occlusion was induced by injection of 0.5 mL of cyanoacrylate into the superior sagittal sinus and by immediate ligation of both external jugular veins in chloralose-urethane anesthetized cats (n = 24). Capillaries in the adjacent cortex (marginal and suprasylvian cortex) and remote cortex (piriform cortex) were injected with Evans blue dye 2 minutes before sacrifice at 15-minute and 120-minute postsinus occlusion. The stereologic morphometric parameters including volume density, minimum intercapillary distance, capillary diameter, and number of perfused capillaries were computed on a fluorescence microscopic photograph using an image analysis system. Cerebral blood flow (CBF) was measured by hydrogen clearance method, and brain tissue water content was measured using the dry-wet method. RESULTS In the cortex adjacent to the superior sagittal sinus, the volume density and the number of perfused capillaries were increased significantly (p < 0.02, and p < 0.05, respectively) and the minimum intercapillary distance was decreased significantly (p < 0.02) at 15 minutes after venous occlusion (n = 10). Cerebral blood flow (CBF) was also decreased to 53% of that in the control group (p < 0.01). Although the morphologic parameters returned to the control level by 120 minutes after venous occlusion, the CBF remained decreased after venous occlusion. No change was observed in the water content of the adjacent gray matter at 15 minutes after venous occlusion; however, it was increased (p < 0.05) at 120 minutes. CONCLUSION These results indicate that the recruitment of reserve capillaries occurs during the early phase of venous occlusion. While CBF decreased to half of the control after venous occlusion, capillary perfusion remained above or near the control level until 120 minutes postocclusion, suggesting that venous recruitment would be potentially beneficial in clinical patients in the early stage of venous occlusion.
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Affiliation(s)
- H Kanaiwa
- Department of Neurosurgery, Nagoya University School of Medicine, Japan
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Brain SPECT and transcranial doppler ultrasound in vasospasm-induced delayed cerebral ischemia after subarachnoid hemorrhage. J Stroke Cerebrovasc Dis 1992; 2:12-21. [DOI: 10.1016/s1052-3057(10)80029-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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