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Fruekilde SK, Bailey CJ, Lambertsen KL, Clausen BH, Carlsen J, Xu NL, Drasbek KR, Gutiérrez-Jiménez E. Disturbed microcirculation and hyperaemic response in a murine model of systemic inflammation. J Cereb Blood Flow Metab 2022; 42:2303-2317. [PMID: 35999817 PMCID: PMC9670001 DOI: 10.1177/0271678x221112278] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Systemic inflammation affects cognitive functions and increases the risk of dementia. This phenomenon is thought to be mediated in part by cytokines that promote neuronal survival, but the continuous exposure to which may lead to neurodegeneration. The effects of systemic inflammation on cerebral blood vessels, and their provision of adequate oxygen to support critical brain parenchymal cell functions, remains unclear. Here, we demonstrate that neurovascular coupling is profoundly disturbed in lipopolysaccharide (LPS) induced systemic inflammation in awake mice. In the 24 hours following LPS injection, the hyperaemic response of pial vessels to functional activation was attenuated and delayed. Concurrently, under steady-state conditions, the capillary network displayed a significant increase in the number of capillaries with blocked blood flow, as well as increased duration of 'capillary stalls'-a phenomenon previously reported in animal models of stroke and Alzheimer's disease pathology. We speculate that vascular changes and impaired oxygen availability may affect brain functions following acute systemic inflammation and contribute to the long-term risk of neurodegenerative changes associated with chronic, systemic inflammation.
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Affiliation(s)
- Signe Kirk Fruekilde
- Center for Functionally Integrative Neuroscience (CFIN), Department of Clinical Medicine, 1006Aarhus University, Aarhus C, Denmark.,Sino-Danish Center for Education and Research (SDC), University of Chinese Academy of Sciences, Beijing, P.R. China
| | - Christopher J Bailey
- Center for Functionally Integrative Neuroscience (CFIN), Department of Clinical Medicine, 1006Aarhus University, Aarhus C, Denmark.,Sino-Danish Center for Education and Research (SDC), University of Chinese Academy of Sciences, Beijing, P.R. China
| | - Kate Lykke Lambertsen
- Department of Neurobiology Research, Institute of Molecular Medicine, 6174University of Southern Denmark, Odense C, Denmark.,BRIDGE - Brain Research - Inter-Disciplinary Guided Excellence, Department of Clinical Research, 6174University of Southern Denmark, Odense C, Denmark.,Department of Neurology, Odense University Hospital, Odense C, Denmark
| | - Bettina Hjelm Clausen
- Department of Neurobiology Research, Institute of Molecular Medicine, 6174University of Southern Denmark, Odense C, Denmark.,BRIDGE - Brain Research - Inter-Disciplinary Guided Excellence, Department of Clinical Research, 6174University of Southern Denmark, Odense C, Denmark
| | - Jasper Carlsen
- Research Unit for Molecular Medicine (MMF), Department of Clinical Medicine, 1006Aarhus University, Aarhus N, Denmark
| | - Ning-Long Xu
- Sino-Danish Center for Education and Research (SDC), University of Chinese Academy of Sciences, Beijing, P.R. China.,Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, P.R. China
| | - Kim Ryun Drasbek
- Center for Functionally Integrative Neuroscience (CFIN), Department of Clinical Medicine, 1006Aarhus University, Aarhus C, Denmark.,Sino-Danish Center for Education and Research (SDC), University of Chinese Academy of Sciences, Beijing, P.R. China
| | - Eugenio Gutiérrez-Jiménez
- Center for Functionally Integrative Neuroscience (CFIN), Department of Clinical Medicine, 1006Aarhus University, Aarhus C, Denmark
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Chen Y, Galea I, Macdonald RL, Wong GKC, Zhang JH. Rethinking the initial changes in subarachnoid haemorrhage: Focusing on real-time metabolism during early brain injury. EBioMedicine 2022; 83:104223. [PMID: 35973388 PMCID: PMC9396538 DOI: 10.1016/j.ebiom.2022.104223] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 07/17/2022] [Accepted: 07/30/2022] [Indexed: 11/16/2022] Open
Abstract
Over the last two decades, neurological researchers have uncovered many pathophysiological mechanisms associated with subarachnoid haemorrhage (SAH), with early brain injury and delayed cerebral ischaemia both contributing to morbidity and mortality. The current dilemma in SAH management inspired us to rethink the nature of the insult in SAH: sudden bleeding into the subarachnoid space and hypoxia due to disturbed cerebral circulation and increased intracranial pressure, generating exogenous stimuli and subsequent pathophysiological processes. Exogenous stimuli are defined as factors which the brain tissue is not normally exposed to when in the healthy state. Intersections of these initial pathogenic factors lead to secondary brain injury with related metabolic changes after SAH. Herein, we summarized the current understanding of efforts to monitor and analyse SAH-related metabolic changes to identify those precise pathophysiological processes and potential therapeutic strategies; in particular, we highlight the restoration of normal cerebrospinal fluid circulation and the normalization of brain-blood interface physiology to alleviate early brain injury and delayed neurological deterioration after SAH.
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Affiliation(s)
- Yujie Chen
- Department of Neurosurgery and State Key Laboratory of Trauma, Burn and Combined Injury, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China; CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
| | - Ian Galea
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom
| | - R Loch Macdonald
- Community Neurosciences Institutes, Community Regional Medical Center, Fresno, CA 93701, USA
| | - George Kwok Chu Wong
- Division of Neurosurgery, Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong 999077, China
| | - John H Zhang
- Neuroscience Research Center, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA; Department of Physiology and Pharmacology, Loma Linda University School of Medicine, Loma Linda, CA 92354, USA.
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Faulhaber LD, D’Costa O, Shih AY, Gust J. Antibody-based in vivo leukocyte label for two-photon brain imaging in mice. NEUROPHOTONICS 2022; 9:031917. [PMID: 35637871 PMCID: PMC9128835 DOI: 10.1117/1.nph.9.3.031917] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 04/21/2022] [Indexed: 06/15/2023]
Abstract
Significance: To study leukocyte-endothelial interactions in a living system, robust and specific leukocyte labeling techniques are needed for in vivo two-photon microscopy of the cerebral microvasculature. Aim: We tested fluorophore-conjugated anti-CD45.2 monoclonal antibodies (mAb) to optimize dosing and two-photon imaging parameters for leukocyte labeling in healthy mice and a venous microstroke model. Approach: We retro-orbitally injected anti-CD45.2 mAb at 0.04, 0.4, and 2 mg / kg into BALB/c mice and used flow cytometry to analyze antibody saturation. Leukocyte labeling in the cortical microvasculature was examined by two-photon imaging. We also tested the application of CD45.2 mAb in a pathological leukocyte-endothelial adhesion model by photothrombotically occluding cortical penetrating venules. Results: We found that 0.4 mg / kg of anti-CD45.2 antibody intravenously was sufficient to label 95% of circulating leukocytes. There was no depletion of circulating leukocytes after 24 h at the dosages tested. Labeled leukocytes could be observed as deep as 550 μ m from the cortical surface. The antibody reliably labeled rolling, crawling, and adherent leukocytes in venules around the stroke-affected tissues. Conclusion: We show that the anti-CD45.2 mAb is a robust reagent for acute labeling of leukocytes during in vivo two-photon microscopy of the cortical microvasculature.
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Affiliation(s)
- Lila D. Faulhaber
- Center for Developmental Biology and Regenerative Medicine, Seattle, Washington, United States
- Seattle Children’s Research Institute, Center for Integrative Brain Research, Seattle, Washington, United States
| | - Olivia D’Costa
- Seattle Children’s Research Institute, Center for Integrative Brain Research, Seattle, Washington, United States
| | - Andy Y. Shih
- Center for Developmental Biology and Regenerative Medicine, Seattle, Washington, United States
- University of Washington, Department of Pediatrics, Seattle, Washington, United States
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Juliane Gust
- Seattle Children’s Research Institute, Center for Integrative Brain Research, Seattle, Washington, United States
- University of Washington, Department of Neurology, Seattle, Washington, United States
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Solár P, Zamani A, Lakatosová K, Joukal M. The blood-brain barrier and the neurovascular unit in subarachnoid hemorrhage: molecular events and potential treatments. Fluids Barriers CNS 2022; 19:29. [PMID: 35410231 PMCID: PMC8996682 DOI: 10.1186/s12987-022-00312-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/24/2022] [Indexed: 12/12/2022] Open
Abstract
The response of the blood-brain barrier (BBB) following a stroke, including subarachnoid hemorrhage (SAH), has been studied extensively. The main components of this reaction are endothelial cells, pericytes, and astrocytes that affect microglia, neurons, and vascular smooth muscle cells. SAH induces alterations in individual BBB cells, leading to brain homeostasis disruption. Recent experiments have uncovered many pathophysiological cascades affecting the BBB following SAH. Targeting some of these pathways is important for restoring brain function following SAH. BBB injury occurs immediately after SAH and has long-lasting consequences, but most changes in the pathophysiological cascades occur in the first few days following SAH. These changes determine the development of early brain injury as well as delayed cerebral ischemia. SAH-induced neuroprotection also plays an important role and weakens the negative impact of SAH. Supporting some of these beneficial cascades while attenuating the major pathophysiological pathways might be decisive in inhibiting the negative impact of bleeding in the subarachnoid space. In this review, we attempt a comprehensive overview of the current knowledge on the molecular and cellular changes in the BBB following SAH and their possible modulation by various drugs and substances.
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Affiliation(s)
- Peter Solár
- Department of Anatomy, Cellular and Molecular Neurobiology Research Group, Faculty of Medicine, Masaryk University, 625 00, Brno, Czech Republic
- Department of Neurosurgery, Faculty of Medicine, Masaryk University and St. Anne's University Hospital Brno, Pekařská 53, 656 91, Brno, Czech Republic
| | - Alemeh Zamani
- Department of Anatomy, Cellular and Molecular Neurobiology Research Group, Faculty of Medicine, Masaryk University, 625 00, Brno, Czech Republic
| | - Klaudia Lakatosová
- Department of Anatomy, Cellular and Molecular Neurobiology Research Group, Faculty of Medicine, Masaryk University, 625 00, Brno, Czech Republic
| | - Marek Joukal
- Department of Anatomy, Cellular and Molecular Neurobiology Research Group, Faculty of Medicine, Masaryk University, 625 00, Brno, Czech Republic.
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Dienel A, Hong SH, Guzman J, Kumar TP, Blackburn SL, McBride DW. Confirming Subarachnoid Hemorrhage Induction in the Endovascular Puncture Mouse Model. BRAIN HEMORRHAGES 2022. [DOI: 10.1016/j.hest.2022.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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Dienel A, Kumar T P, Blackburn SL, McBride DW. Role of platelets in the pathogenesis of delayed injury after subarachnoid hemorrhage. J Cereb Blood Flow Metab 2021; 41:2820-2830. [PMID: 34112003 PMCID: PMC8756481 DOI: 10.1177/0271678x211020865] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Aneurysmal subarachnoid hemorrhage (aSAH) patients develop delayed cerebral ischemia and delayed deficits (DCI) within 2 weeks of aneurysm rupture at a rate of approximately 30%. DCI is a major contributor to morbidity and mortality after SAH. The cause of DCI is multi-factorial with contributions from microthrombi, blood vessel constriction, inflammation, and cortical spreading depolarizations. Platelets play central roles in hemostasis, inflammation, and vascular function. Within this review, we examine the potential roles of platelets in microthrombi formation, large artery vasospasm, microvessel constriction, inflammation, and cortical spreading depolarization. Evidence from experimental and clinical studies is provided to support the role(s) of platelets in each pathophysiology which contributes to DCI. The review concludes with a suggestion for future therapeutic targets to prevent DCI after aSAH.
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Affiliation(s)
- Ari Dienel
- The Vivian L. Smith Department of Neurosurgery, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Peeyush Kumar T
- The Vivian L. Smith Department of Neurosurgery, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Spiros L Blackburn
- The Vivian L. Smith Department of Neurosurgery, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Devin W McBride
- The Vivian L. Smith Department of Neurosurgery, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, USA
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Hokari M, Shimbo D, Uchida K, Gekka M, Asaoka K, Itamoto K. Characteristics of MRI Findings after Subarachnoid Hemorrhage and D-Dimer as a Predictive Value for Early Brain Injury. J Stroke Cerebrovasc Dis 2021; 31:106073. [PMID: 34689052 DOI: 10.1016/j.jstrokecerebrovasdis.2021.106073] [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: 05/27/2021] [Revised: 08/14/2021] [Accepted: 08/16/2021] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The pathological mechanisms of early brain injury (EBI) have remained obscure. Several studies have reported on the neuroradiological findings of EBI. However, to our knowledge, no study has attempted to explore the mechanism of EBI after subarachnoid hemorrhage (SAH). Therefore, this study evaluates whether the initial plasma D-dimer levels were associated with EBI, classifies magnetic resonance imaging (MRI) findings, and speculates about the mechanism of EBI. METHODS This study included 97 patients hospitalized within 24 h from the onset of nontraumatic SAH. The patients underwent MRI within 0-5 days from onset (before vasospasm) to detect EBI. EBI was radiologically defined as diffusion-weighted imaging (DWI)-positive lesions that appear dark on apparent diffusion coefficient maps, excluding procedure-related lesions. EBI, plasma D-dimer levels, and clinical features were retrospectively investigated. RESULTS Elevated D-dimer levels were associated with poor outcomes. Patients with EBI had significantly higher D-dimer levels than those without EBI. EBI was detected in 24 patients (27.3%) of all, and in 22 (45%) of 49 patients with World Federation of Neurosurgical Societies (WFNS) grade 4-5 SAH. EBI was frequently observed in the paramedian frontal lobe. There were several types of the pathology in EBI, including widespread symmetrical cerebral cortex lesions, focal cortex lesions, periventricular injury, and other lesions impossible to classify due to unknown mechanisms such as thrombotic complication and microcirculatory disturbance, ultra-early spasm, and spreading depolarization. CONCLUSIONS This study suggests that D-dimer levels predict poor outcomes in patients with SAH and that EBI was associated high D-dimer levels.
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Affiliation(s)
- Masaaki Hokari
- Department of Neurosurgery, Teine Keijinkai Hospital, Sapporo, Hokkaido.
| | - Daisuke Shimbo
- Department of Neurosurgery, Teine Keijinkai Hospital, Sapporo, Hokkaido
| | - Kazuki Uchida
- Department of Neurosurgery, Teine Keijinkai Hospital, Sapporo, Hokkaido
| | - Masayuki Gekka
- Department of Neurosurgery, Teine Keijinkai Hospital, Sapporo, Hokkaido
| | - Katsuyuki Asaoka
- Department of Neurosurgery, Teine Keijinkai Hospital, Sapporo, Hokkaido
| | - Koji Itamoto
- Department of Neurosurgery, Teine Keijinkai Hospital, Sapporo, Hokkaido
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8
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Wang DL, Lin P, Lin ZY, Zheng SF, Shang-Guan HC, Kang DZ, Chen GR, Zhang YB, Wen CS, Lin YX, Yao PS. Lower Hemoglobin Levels Are Associated with Acute Seizures in Patients with Ruptured Cerebral Aneurysms. World Neurosurg 2019; 127:e1237-e1241. [DOI: 10.1016/j.wneu.2019.04.115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 04/11/2019] [Accepted: 04/12/2019] [Indexed: 11/25/2022]
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9
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Neutrophil adhesion in brain capillaries reduces cortical blood flow and impairs memory function in Alzheimer's disease mouse models. Nat Neurosci 2019; 22:413-420. [PMID: 30742116 PMCID: PMC6508667 DOI: 10.1038/s41593-018-0329-4] [Citation(s) in RCA: 276] [Impact Index Per Article: 55.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 12/17/2018] [Indexed: 01/18/2023]
Abstract
Cerebral blood flow (CBF) reductions in Alzheimer’s disease (AD) patients and related mouse models have been recognized for decades, but the underlying mechanisms and resulting consequences on AD pathogenesis remain poorly understood. In APP/PS1 and 5xFAD mice we found that an increased number of cortical capillaries had stalled blood flow as compared to wildtype animals, largely due to neutrophils that adhered in capillary segments and blocked blood flow. Administration of antibodies against the neutrophil marker Ly6G reduced the number of stalled capillaries, leading to an immediate increase in CBF and to rapidly improved performance in spatial and working memory tasks. This study identified a novel cellular mechanism that explains the majority of the CBF reduction seen in two mouse models of AD and demonstrated that improving CBF rapidly improved short-term memory function. Restoring cerebral perfusion by preventing neutrophil adhesion may provide a novel strategy for improving cognition in AD patients.
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10
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Spaide RF, Fujimoto JG, Waheed NK, Sadda SR, Staurenghi G. Optical coherence tomography angiography. Prog Retin Eye Res 2018; 64:1-55. [PMID: 29229445 PMCID: PMC6404988 DOI: 10.1016/j.preteyeres.2017.11.003] [Citation(s) in RCA: 992] [Impact Index Per Article: 165.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 11/20/2017] [Accepted: 11/22/2017] [Indexed: 02/07/2023]
Abstract
Optical coherence tomography (OCT) was one of the biggest advances in ophthalmic imaging. Building on that platform, OCT angiography (OCTA) provides depth resolved images of blood flow in the retina and choroid with levels of detail far exceeding that obtained with older forms of imaging. This new modality is challenging because of the need for new equipment and processing techniques, current limitations of imaging capability, and rapid advancements in both imaging and in our understanding of the imaging and applicable pathophysiology of the retina and choroid. These factors lead to a steep learning curve, even for those with a working understanding dye-based ocular angiography. All for a method of imaging that is a little more than 10 years old. This review begins with a historical account of the development of OCTA, and the methods used in OCTA, including signal processing, image generation, and display techniques. This forms the basis to understand what OCTA images show as well as how image artifacts arise. The anatomy and imaging of specific vascular layers of the eye are reviewed. The integration of OCTA in multimodal imaging in the evaluation of retinal vascular occlusive diseases, diabetic retinopathy, uveitis, inherited diseases, age-related macular degeneration, and disorders of the optic nerve is presented. OCTA is an exciting, disruptive technology. Its use is rapidly expanding in clinical practice as well as for research into the pathophysiology of diseases of the posterior pole.
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Affiliation(s)
- Richard F Spaide
- Vitreous, Retina, Macula Consultants of New York, New York, NY, United States.
| | - James G Fujimoto
- Department of Electrical Engineering & Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge MA, United States
| | - Nadia K Waheed
- The Department of Ophthalmology, Tufts University School of Medicine, Boston MA, United States
| | - Srinivas R Sadda
- Doheny Eye Institute, University of California - Los Angeles, Los Angeles, CA, United States
| | - Giovanni Staurenghi
- Eye Clinic, Department of Biomedical and Clinical Sciences "Luigi Sacco", Luigi Sacco Hospital, University of Milan, Milan, Italy
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Yu SJ, Buerck JP, O'Rear EA, Whitsett TL. Possible erythrocyte contributions to and exacerbation of the post-thrombolytic no-reflow phenomenon. Biorheology 2018; 54:81-93. [PMID: 29332028 DOI: 10.3233/bir-17144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Reperfusion injury often occurs with therapeutic intervention addressing the arterial occlusions causing acute myocardial infarction and stroke. The no-reflow phenomenon has been ascribed to leukocyte plugging and blood vessel constriction in the microcirculation. OBJECTIVE To assess possible red cell contributions to post-thrombolytic no-reflow phenomenon. METHODS Blood clots were formed by recalcifying 1 ml of citrated fresh human venous blood and then lysed by adding 1,000 units of streptokinase (SK) at several intervals within 1 hour. Red cell deformability was tested by both a microscopic photometric and a filtration technique, viscosity by a cone and plate viscometer, and erythrocyte aggregation by an optical aggregometer. RESULTS Two sampling methods were devised for the microscopic photometric test, both of which indicated increases of erythrocyte stiffness after being lysed from the clot by SK. In accompanying experiments, the viscosity, aggregation and filterability of the post-lytic erythrocytes were assessed. Results indicated increased viscosity in Ringer's, decreased aggregation index and filterability through a 5 μm pore size Nuclepore membrane. CONCLUSION Findings demonstrated that post-lytic changes in red cell deformability do occur which could contribute to the no-reflow phenomenon.
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Affiliation(s)
- Shang-Jen Yu
- Department of Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, OK 73019, USA
| | - James P Buerck
- Department of Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, OK 73019, USA
| | - Edgar A O'Rear
- Department of Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, OK 73019, USA
| | - Thomas L Whitsett
- Department of Medicine, University of Oklahoma Health Science Center, Oklahoma City, OK 73014, USA
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MICROVASCULAR FLOW ABNORMALITIES ASSOCIATED WITH RETINAL VASCULITIS: A Potential of Mechanism of Retinal Injury. Retina 2018; 37:1034-1042. [PMID: 27759582 DOI: 10.1097/iae.0000000000001359] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
PURPOSE To investigate the structural optical coherence tomography and related microvascular flow characteristics in eyes with retinal vasculitis. METHODS Regions involved with perivascular infiltration in eyes with retinal vasculitis, but no evidence of large vessel occlusion were evaluated with optical coherence tomography (OCT), OCT angiography, and fluorescein angiography. RESULTS Ten eyes of 5 patients with a variety of etiologies of retinal vasculitis were evaluated. These patients did not have either cotton wool spots or deeper placoid areas of retinal ischemia. Around large vessels there was perivascular infiltration with leakage and staining seen during fluorescein angiography. Structural OCT showed slight thickening with loss of visualization of normal retinal laminations. OCT angiography showed a lack of flow signal in capillary sized vessels in the same areas. Treatment resulted in a rapid thinning of the affected areas, with the inner and middle layers of the retina becoming thinner than surrounding uninvolved areas. OCT angiography did not show a return of capillary perfusion in these regions. The thickness change in the structural OCT as shown by a heat map had a pattern mimicking the original perivascular infiltration around large retinal vessels. CONCLUSION Capillary level perfusion abnormalities can develop in regions adjacent to large vessel inflammatory infiltrate that result in retinal thinning without the development of usual stigmata of acute microvascular flow obstruction such as cotton wool spots. This suggests that retinal damage may occur in retinal vasculitis that would not be recognized without using OCT-based imaging modalities.
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13
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Sasaki K, Mutoh T, Nakamura K, Kojima I, Taki Y, Suarez JI, Ishikawa T. MRI-based in vivo assessment of early cerebral infarction in a mouse filament perforation model of subarachnoid hemorrhage. Neurosci Lett 2017; 653:173-176. [PMID: 28552456 DOI: 10.1016/j.neulet.2017.05.047] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 05/13/2017] [Accepted: 05/22/2017] [Indexed: 11/15/2022]
Abstract
BACKGROUND AND PURPOSE Experimental subarachnoid hemorrhage (SAH) by endovascular filament perforation method is used widely in mice, but it sometimes present acute cerebral infarctions with varied magnitude and anatomical location. This study aimed to determine the prevalence and location of the acute ischemic injury in this experimental model. METHODS Male C57BL/6 mice were subjected to SAH by endovascular perforation. Distribution of SAH was defined by T2*-weighted images within 1h after SAH. Prevalence and location of acute infarction were assessed by diffusion-weighted MR images on day 1 after the induction. RESULTS Among 72 mice successfully acquired post-SAH MR images, 29 (40%) developed acute infarction. Location of the infarcts was classified into either single infarct (ipsilateral cortex, n=12; caudate putamen, n=3; hippocampus, n=1) or multiple lesions (cortex and caudate putamen, n=6; cortex and hippocampus, n=2; cortex, hippocampus and thalamus/hypothalamus, n=3; bilateral cortex, n=2). The mortality rate within 24h was significantly higher in mice with multiple infarcts than those with single lesion (30% versus 0%; P=0.03). Distribution of the ischemic lesion positively correlated with MRI-evidenced SAH grading (r2=0.31, P=0.0002). CONCLUSION Experimental SAH immediately after the vessel perforation can induce acute cerebral infarction in varying vascular territories, resulting in increased mortality. The present model may in part, help researchers to interpret the mechanism of clinically-evidenced early multiple combined infarction.
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Affiliation(s)
- Kazumasu Sasaki
- Research Institute for Brain and Blood Vessels-AKITA, Akita, Japan; Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
| | - Tatsushi Mutoh
- Research Institute for Brain and Blood Vessels-AKITA, Akita, Japan; Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan.
| | | | - Ikuho Kojima
- Research Institute for Brain and Blood Vessels-AKITA, Akita, Japan; Department of Oral Diagnosis & Radiology, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - Yasuyuki Taki
- Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
| | - Jose Ignacio Suarez
- Department of Neurology-Vascular Neurology and Neurocritical Care, Baylor College of Medicine, Houston, TX, USA
| | - Tatsuya Ishikawa
- Research Institute for Brain and Blood Vessels-AKITA, Akita, Japan
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14
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Inotropic support against early brain injury improves cerebral hypoperfusion and outcomes in a murine model of subarachnoid hemorrhage. Brain Res Bull 2016; 130:18-26. [PMID: 28017781 DOI: 10.1016/j.brainresbull.2016.12.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 12/20/2016] [Indexed: 11/23/2022]
Abstract
Early brain injury/ischemia is a recent therapeutic target that contributes to triggering delayed cerebral ischemia (DCI) in the setting of subarachnoid hemorrhage (SAH). This study aimed to determine the role of dobutamine for inotropic cardiac support in improving cerebral blood flow (CBF) and outcomes after experimental SAH, mediated by hypoxia-inducible factor (HIF). Thirty-one mice were subjected to SAH by endovascular perforation, and assigned to either 2% isoflurane postconditioning performed between 1 and 2.5h after SAH induction or concomitant intravenous dobutamine infusion (15μg/kg/min) with or without HIF inhibitor 2-methoxyestradiol (2ME2) (10mg/kg) administered intraperitoneally. Neurobehavioral function was assessed daily by neurological scores and open field testing. DCI was defined 3days later by detecting a new infarction on MRI. Global CBF depression was notable early after SAH, but dobutamine showed significant improvement in CBF, lower incidence of DCI, and better recovery of neuroscores and open field test variables compared with isoflurane postconditioning (P<0.05). CBF over the entire brain on day 1 predicted DCI with a cut-off of 36.5ml/100g/min (80% specificity and 67% sensitivity), with a better area under the curve (0.83 versus 0.75) than the hemispheric CBF measured on the perforated side. The dobutamine-mediated outcomes were attenuated (P<0.05) by 2ME2 pretreatment. The data suggest that cardiac support with dobutamine improves global CBF depression induced by early brain injury, leading to reduced prevalence of DCI and better functional outcomes after experimental SAH, in which HIF may be acting as a critical mediator.
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