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Bonney SK, Nielson CD, Sosa MJ, Bonnar O, Shih AY. Capillary regression leads to sustained local hypoperfusion by inducing constriction of upstream transitional vessels. Proc Natl Acad Sci U S A 2024; 121:e2321021121. [PMID: 39236241 PMCID: PMC11406265 DOI: 10.1073/pnas.2321021121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 08/07/2024] [Indexed: 09/07/2024] Open
Abstract
In the brain, a microvascular sensory web coordinates oxygen delivery to regions of neuronal activity. This involves a dense network of capillaries that send conductive signals upstream to feeding arterioles to promote vasodilation and blood flow. Although this process is critical to the metabolic supply of healthy brain tissue, it may also be a point of vulnerability in disease. Deterioration of capillary networks is a feature of many neurological disorders and injuries and how this web is engaged during vascular damage remains unknown. We performed in vivo two-photon microscopy on young adult mural cell reporter mice and induced focal capillary injuries using precise two-photon laser irradiation of single capillaries. We found that ~59% of the injuries resulted in regression of the capillary segment 7 to 14 d following injury, and the remaining repaired to reestablish blood flow within 7 d. Injuries that resulted in capillary regression induced sustained vasoconstriction in the upstream arteriole-capillary transition (ACT) zone at least 21 days postinjury in both awake and anesthetized mice. The degree of vasomotor dynamics was chronically attenuated in the ACT zone consequently reducing blood flow in the ACT zone and in secondary, uninjured downstream capillaries. These findings demonstrate how focal capillary injury and regression can impair the microvascular sensory web and contribute to cerebral hypoperfusion.
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Affiliation(s)
- Stephanie K Bonney
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA 98101
| | - Cara D Nielson
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA 98101
- Graduate Program in Neuroscience, University of Washington, Seattle, WA 98195
| | - Maria J Sosa
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA 98101
| | - Orla Bonnar
- MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02129
| | - Andy Y Shih
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA 98101
- Department of Pediatrics, University of Washington, Seattle, WA 98195
- Department of Bioengineering, University of Washington, Seattle, WA 98195
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2
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Bonney SK, Nielson CD, Sosa MJ, Shih AY. Capillary regression leads to sustained local hypoperfusion by inducing constriction of upstream transitional vessels. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.28.564529. [PMID: 37961686 PMCID: PMC10635020 DOI: 10.1101/2023.10.28.564529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
In the brain, a microvascular sensory web coordinates oxygen delivery to regions of neuronal activity. This involves a dense network of capillaries that send conductive signals upstream to feeding arterioles to promote vasodilation and blood flow. Although this process is critical to the metabolic supply of healthy brain tissue, it may also be a point of vulnerability in disease. Deterioration of capillary networks is a hallmark of many neurological disorders and how this web is engaged during vascular damage remains unknown. We performed in vivo two-photon microscopy on young adult mural cell reporter mice and induced focal capillary injuries using precise two-photon laser irradiation of single capillaries. We found that ∼63% of the injuries resulted in regression of the capillary segment 7-14 days following injury, and the remaining repaired to re-establish blood flow within 7 days. Injuries that resulted in capillary regression induced sustained vasoconstriction in the upstream arteriole-capillary transition (ACT) zone at least 21 days post-injury in both awake and anesthetized mice. This abnormal vasoconstriction involved attenuation of vasomotor dynamics and uncoupling from mural cell calcium signaling following capillary regression. Consequently, blood flow was reduced in the ACT zone and in secondary, uninjured downstream capillaries. These findings demonstrate how capillary injury and regression, as often seen in age-related neurological disease, can impair the microvascular sensory web and contribute to cerebral hypoperfusion. SIGNIFICANCE Deterioration of the capillary network is a characteristic of many neurological diseases and can exacerbate neuronal dysfunction and degeneration due to poor blood perfusion. Here we show that focal capillary injuries can induce vessel regression and elicit sustained vasoconstriction in upstream transitional vessels that branch from cortical penetrating arterioles. This reduces blood flow to broader, uninjured regions of the same microvascular network. These findings suggest that widespread and cumulative damage to brain capillaries in neurological disease may broadly affect blood supply and contribute to hypoperfusion through their remote actions.
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3
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Epp R, Glück C, Binder NF, El Amki M, Weber B, Wegener S, Jenny P, Schmid F. The role of leptomeningeal collaterals in redistributing blood flow during stroke. PLoS Comput Biol 2023; 19:e1011496. [PMID: 37871109 PMCID: PMC10621965 DOI: 10.1371/journal.pcbi.1011496] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 11/02/2023] [Accepted: 09/03/2023] [Indexed: 10/25/2023] Open
Abstract
Leptomeningeal collaterals (LMCs) connect the main cerebral arteries and provide alternative pathways for blood flow during ischaemic stroke. This is beneficial for reducing infarct size and reperfusion success after treatment. However, a better understanding of how LMCs affect blood flow distribution is indispensable to improve therapeutic strategies. Here, we present a novel in silico approach that incorporates case-specific in vivo data into a computational model to simulate blood flow in large semi-realistic microvascular networks from two different mouse strains, characterised by having many and almost no LMCs between middle and anterior cerebral artery (MCA, ACA) territories. This framework is unique because our simulations are directly aligned with in vivo data. Moreover, it allows us to analyse perfusion characteristics quantitatively across all vessel types and for networks with no, few and many LMCs. We show that the occlusion of the MCA directly caused a redistribution of blood that was characterised by increased flow in LMCs. Interestingly, the improved perfusion of MCA-sided microvessels after dilating LMCs came at the cost of a reduced blood supply in other brain areas. This effect was enhanced in regions close to the watershed line and when the number of LMCs was increased. Additional dilations of surface and penetrating arteries after stroke improved perfusion across the entire vasculature and partially recovered flow in the obstructed region, especially in networks with many LMCs, which further underlines the role of LMCs during stroke.
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Affiliation(s)
- Robert Epp
- Institute of Fluid Dynamics, ETH Zurich, Zurich, Switzerland
| | - Chaim Glück
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Nadine Felizitas Binder
- Deptartment of Neurology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Mohamad El Amki
- Deptartment of Neurology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Susanne Wegener
- Deptartment of Neurology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Patrick Jenny
- Institute of Fluid Dynamics, ETH Zurich, Zurich, Switzerland
| | - Franca Schmid
- Institute of Fluid Dynamics, ETH Zurich, Zurich, Switzerland
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
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4
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Murata J, Unekawa M, Kudo Y, Kotani M, Kanno I, Izawa Y, Tomita Y, Tanaka KF, Nakahara J, Masamoto K. Acceleration of the Development of Microcirculation Embolism in the Brain due to Capillary Narrowing. Stroke 2023; 54:2135-2144. [PMID: 37309687 DOI: 10.1161/strokeaha.122.042416] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 05/05/2023] [Indexed: 06/14/2023]
Abstract
BACKGROUND Cerebral microvascular obstruction is critically involved in recurrent stroke and decreased cerebral blood flow with age. The obstruction must occur in the capillary with a greater resistance to perfusion pressure through the microvascular networks. However, little is known about the relationship between capillary size and embolism formation. This study aimed to determine whether the capillary lumen space contributes to the development of microcirculation embolism. METHODS To spatiotemporally manipulate capillary diameters in vivo, transgenic mice expressing the light-gated cation channel protein ChR2 (channelrhodopsin-2) in mural cells were used. The spatiotemporal changes in the regional cerebral blood flow in response to the photoactivation of ChR2 mural cells were first characterized using laser speckle flowgraphy. Capillary responses to optimized photostimulation were then examined in vivo using 2-photon microscopy. Finally, microcirculation embolism due to intravenously injected fluorescent microbeads was compared under conditions with or without photoactivation of ChR2 mural cells. RESULTS Following transcranial photostimulation, the stimulation intensity-dependent decrease in cerebral blood flow centered at the irradiation was observed (14%-49% decreases relative to the baseline). The cerebrovascular response to photostimulation showed significant constriction of the cerebral arteries and capillaries but not of the veins. As a result of vasoconstriction, a temporal stall of red blood cell flow occurred in the capillaries of the venous sides. The 2-photon excitation of a single ChR2 pericyte demonstrated the partial shrinkage of capillaries (7% relative to the baseline) around the stimulated cell. With the intravenous injection of microbeads, the occurrence of microcirculation embolism was significantly enhanced (11% increases compared to the control) with photostimulation. CONCLUSIONS Capillary narrowing increases the risk of developing microcirculation embolism in the venous sides of the cerebral capillaries.
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Affiliation(s)
- Juri Murata
- Graduate School of Informatics and Engineering (J.M., Y.K., M.K., K.M.), University of Electro-Communications, Tokyo, Japan
| | - Miyuki Unekawa
- Department of Neurology (M.U., Y.I., Y.T., J.N.), Keio University School of Medicine, Tokyo, Japan
| | - Yuya Kudo
- Graduate School of Informatics and Engineering (J.M., Y.K., M.K., K.M.), University of Electro-Communications, Tokyo, Japan
| | - Maho Kotani
- Graduate School of Informatics and Engineering (J.M., Y.K., M.K., K.M.), University of Electro-Communications, Tokyo, Japan
| | - Iwao Kanno
- Department of Functional Brain Imaging, National Institutes for Quantum Science and Technology, Chiba, Japan (I.K.)
| | - Yoshikane Izawa
- Department of Neurology (M.U., Y.I., Y.T., J.N.), Keio University School of Medicine, Tokyo, Japan
| | - Yutaka Tomita
- Department of Neurology (M.U., Y.I., Y.T., J.N.), Keio University School of Medicine, Tokyo, Japan
- Tomita Hospital, Aichi, Japan (Y.T.)
| | - Kenji F Tanaka
- Division of Brain Sciences, Institute for Advanced Medical Research (K.F.T.), Keio University School of Medicine, Tokyo, Japan
| | - Jin Nakahara
- Department of Neurology (M.U., Y.I., Y.T., J.N.), Keio University School of Medicine, Tokyo, Japan
| | - Kazuto Masamoto
- Graduate School of Informatics and Engineering (J.M., Y.K., M.K., K.M.), University of Electro-Communications, Tokyo, Japan
- Center for Neuroscience and Biomedical Engineering (K.M.), University of Electro-Communications, Tokyo, Japan
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5
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Althammer F, Roy RK, Kirchner MK, Campos-Lira E, Whitley KE, Davis S, Montanez J, Ferreira-Neto HC, Danh J, Feresin R, Biancardi VC, Zafar U, Parent MB, Stern JE. Angiotensin II-Mediated Neuroinflammation in the Hippocampus Contributes to Neuronal Deficits and Cognitive Impairment in Heart Failure Rats. Hypertension 2023; 80:1258-1273. [PMID: 37035922 PMCID: PMC10192104 DOI: 10.1161/hypertensionaha.123.21070] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 03/22/2023] [Indexed: 04/11/2023]
Abstract
BACKGROUND Heart failure (HF) is a debilitating disease affecting >64 million people worldwide. In addition to impaired cardiovascular performance and associated systemic complications, most patients with HF suffer from depression and substantial cognitive decline. Although neuroinflammation and brain hypoperfusion occur in humans and rodents with HF, the underlying neuronal substrates, mechanisms, and their relative contribution to cognitive deficits in HF remains unknown. METHODS To address this critical gap in our knowledge, we used a well-established HF rat model that mimics clinical outcomes observed in the human population, along with a multidisciplinary approach combining behavioral, electrophysiological, neuroanatomical, molecular and systemic physiological approaches. RESULTS Our studies support neuroinflammation, hypoperfusion/hypoxia, and neuronal deficits in the hippocampus of HF rats, which correlated with the progression and severity of the disease. An increased expression of AT1aRs (Ang II [angiotensin II] receptor type 1a) in hippocampal microglia preceded the onset of neuroinflammation. Importantly, blockade of AT1Rs with a clinically used therapeutic drug (Losartan), and delivered in a clinically relevant manner, efficiently reversed neuroinflammatory end points (but not hypoxia ones), resulting in turn in improved cognitive performance in HF rats. Finally, we show than circulating Ang II can leak and access the hippocampal parenchyma in HF rats, constituting a possible source of Ang II initiating the neuroinflammatory signaling cascade in HF. CONCLUSIONS In this study, we identified a neuronal substrate (hippocampus), a mechanism (Ang II-driven neuroinflammation) and a potential neuroprotective therapeutic target (AT1aRs) for the treatment of cognitive deficits in HF.
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Affiliation(s)
- Ferdinand Althammer
- Center for Neuroinflammation and Cardiometabolic Diseases,
Georgia State University, GA, USA
| | - Ranjan K. Roy
- Center for Neuroinflammation and Cardiometabolic Diseases,
Georgia State University, GA, USA
| | - Matthew K. Kirchner
- Center for Neuroinflammation and Cardiometabolic Diseases,
Georgia State University, GA, USA
| | - Elba Campos-Lira
- Center for Neuroinflammation and Cardiometabolic Diseases,
Georgia State University, GA, USA
- Neuroscience Institute, Georgia State University, GA,
USA
| | | | - Steven Davis
- Neuroscience Institute, Georgia State University, GA,
USA
| | - Juliana Montanez
- Center for Neuroinflammation and Cardiometabolic Diseases,
Georgia State University, GA, USA
| | | | - Jessica Danh
- Department of Nutrition, Georgia State University, Atlanta,
GA 30302, USA
| | - Rafaela Feresin
- Department of Nutrition, Georgia State University, Atlanta,
GA 30302, USA
| | - Vinicia Campana Biancardi
- Anatomy, Physiology, & Pharmacology, College of
Veterinary Medicine, Auburn University, Auburn, AL, USA
| | - Usama Zafar
- Center for Neuroinflammation and Cardiometabolic Diseases,
Georgia State University, GA, USA
- Neuroscience Institute, Georgia State University, GA,
USA
| | - Marise B. Parent
- Center for Neuroinflammation and Cardiometabolic Diseases,
Georgia State University, GA, USA
- Neuroscience Institute, Georgia State University, GA,
USA
- Department of Psychology, Georgia State University,
Atlanta, GA 30302, USA
| | - Javier E. Stern
- Center for Neuroinflammation and Cardiometabolic Diseases,
Georgia State University, GA, USA
- Neuroscience Institute, Georgia State University, GA,
USA
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6
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Barkaway A, Attwell D, Korte N. Immune-vascular mural cell interactions: consequences for immune cell trafficking, cerebral blood flow, and the blood-brain barrier. NEUROPHOTONICS 2022; 9:031914. [PMID: 35581998 PMCID: PMC9107322 DOI: 10.1117/1.nph.9.3.031914] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 04/13/2022] [Indexed: 06/15/2023]
Abstract
Brain barriers are crucial sites for cerebral energy supply, waste removal, immune cell migration, and solute exchange, all of which maintain an appropriate environment for neuronal activity. At the capillary level, where the largest area of brain-vascular interface occurs, pericytes adjust cerebral blood flow (CBF) by regulating capillary diameter and maintain the blood-brain barrier (BBB) by suppressing endothelial cell (EC) transcytosis and inducing tight junction expression between ECs. Pericytes also limit the infiltration of circulating leukocytes into the brain where resident microglia confine brain injury and provide the first line of defence against invading pathogens. Brain "waste" is cleared across the BBB into the blood, phagocytosed by microglia and astrocytes, or removed by the flow of cerebrospinal fluid (CSF) through perivascular routes-a process driven by respiratory motion and the pulsation of the heart, arteriolar smooth muscle, and possibly pericytes. "Dirty" CSF exits the brain and is probably drained around olfactory nerve rootlets and via the dural meningeal lymphatic vessels and possibly the skull bone marrow. The brain is widely regarded as an immune-privileged organ because it is accessible to few antigen-primed leukocytes. Leukocytes enter the brain via the meninges, the BBB, and the blood-CSF barrier. Advances in genetic and imaging tools have revealed that neurological diseases significantly alter immune-brain barrier interactions in at least three ways: (1) the brain's immune-privileged status is compromised when pericytes are lost or lymphatic vessels are dysregulated; (2) immune cells release vasoactive molecules to regulate CBF, modulate arteriole stiffness, and can plug and eliminate capillaries which impairs CBF and possibly waste clearance; and (3) immune-vascular interactions can make the BBB leaky via multiple mechanisms, thus aggravating the influx of undesirable substances and cells. Here, we review developments in these three areas and briefly discuss potential therapeutic avenues for restoring brain barrier functions.
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Affiliation(s)
- Anna Barkaway
- University College London, Department of Neuroscience, Physiology and Pharmacology, London, United Kingdom
| | - David Attwell
- University College London, Department of Neuroscience, Physiology and Pharmacology, London, United Kingdom
| | - Nils Korte
- University College London, Department of Neuroscience, Physiology and Pharmacology, London, United Kingdom
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Guo RB, Dong YF, Yin Z, Cai ZY, Yang J, Ji J, Sun YQ, Huang XX, Xue TF, Cheng H, Zhou XQ, Sun XL. Iptakalim improves cerebral microcirculation in mice after ischemic stroke by inhibiting pericyte contraction. Acta Pharmacol Sin 2022; 43:1349-1359. [PMID: 34697419 PMCID: PMC9160281 DOI: 10.1038/s41401-021-00784-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 09/23/2021] [Indexed: 02/07/2023] Open
Abstract
Pericytes are present tight around the intervals of capillaries, play an essential role in stabilizing the blood-brain barrier, regulating blood flow and immunomodulation, and persistent contraction of pericytes eventually leads to impaired blood flow and poor clinical outcomes in ischemic stroke. We previously show that iptakalim, an ATP-sensitive potassium (K-ATP) channel opener, exerts protective effects in neurons, and glia against ischemia-induced injury. In this study we investigated the impacts of iptakalim on pericytes contraction in stroke. Mice were subjected to cerebral artery occlusion (MCAO), then administered iptakalim (10 mg/kg, ip). We showed that iptakalim administration significantly promoted recovery of cerebral blood flow after cerebral ischemia and reperfusion. Furthermore, we found that iptakalim significantly inhibited pericytes contraction, decreased the number of obstructed capillaries, and improved cerebral microcirculation. Using a collagen gel contraction assay, we demonstrated that cultured pericytes subjected to oxygen-glucose deprivation (OGD) consistently contracted from 3 h till 24 h during reoxygenation, whereas iptakalim treatment (10 μM) notably restrained pericyte contraction from 6 h during reoxygenation. We further showed that iptakalim treatment promoted K-ATP channel opening via suppressing SUR2/EPAC1 complex formation. Consequently, it reduced calcium influx and ET-1 release. Taken together, our results demonstrate that iptakalim, targeted K-ATP channels, can improve microvascular disturbance by inhibiting pericyte contraction after ischemic stroke. Our work reveals that iptakalim might be developed as a promising pericyte regulator for treatment of stroke.
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Affiliation(s)
- Ruo-bing Guo
- grid.89957.3a0000 0000 9255 8984Neuroprotective Drug Discovery Key Laboratory, Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing, 211166 China
| | - Yin-feng Dong
- grid.410745.30000 0004 1765 1045Nanjing University of Chinese Medicine, The Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, 210029 China
| | - Zhi Yin
- grid.412676.00000 0004 1799 0784The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029 China
| | - Zhen-yu Cai
- grid.89957.3a0000 0000 9255 8984Neuroprotective Drug Discovery Key Laboratory, Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing, 211166 China
| | - Jin Yang
- grid.89957.3a0000 0000 9255 8984Neuroprotective Drug Discovery Key Laboratory, Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing, 211166 China
| | - Juan Ji
- grid.89957.3a0000 0000 9255 8984Neuroprotective Drug Discovery Key Laboratory, Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing, 211166 China
| | - Yu-qin Sun
- grid.89957.3a0000 0000 9255 8984Neuroprotective Drug Discovery Key Laboratory, Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing, 211166 China
| | - Xin-xin Huang
- grid.412676.00000 0004 1799 0784The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029 China
| | - Teng-fei Xue
- grid.89957.3a0000 0000 9255 8984Neuroprotective Drug Discovery Key Laboratory, Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing, 211166 China
| | - Hong Cheng
- grid.412676.00000 0004 1799 0784The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029 China
| | - Xi-qiao Zhou
- grid.410745.30000 0004 1765 1045Nanjing University of Chinese Medicine, The Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, 210029 China
| | - Xiu-lan Sun
- grid.89957.3a0000 0000 9255 8984Neuroprotective Drug Discovery Key Laboratory, Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing, 211166 China ,grid.410745.30000 0004 1765 1045Nanjing University of Chinese Medicine, The Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, 210029 China
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8
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Korte N, Ilkan Z, Pearson CL, Pfeiffer T, Singhal P, Rock JR, Sethi H, Gill D, Attwell D, Tammaro P. The Ca2+-gated channel TMEM16A amplifies capillary pericyte contraction and reduces cerebral blood flow after ischemia. J Clin Invest 2022; 132:e154118. [PMID: 35316222 PMCID: PMC9057602 DOI: 10.1172/jci154118] [Citation(s) in RCA: 49] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 03/16/2022] [Indexed: 11/26/2022] Open
Abstract
Pericyte-mediated capillary constriction decreases cerebral blood flow in stroke after an occluded artery is unblocked. The determinants of pericyte tone are poorly understood. We show that a small rise in cytoplasmic Ca2+ concentration ([Ca2+]i) in pericytes activated chloride efflux through the Ca2+-gated anion channel TMEM16A, thus depolarizing the cell and opening voltage-gated calcium channels. This mechanism strongly amplified the pericyte [Ca2+]i rise and capillary constriction evoked by contractile agonists and ischemia. In a rodent stroke model, TMEM16A inhibition slowed the ischemia-evoked pericyte [Ca2+]i rise, capillary constriction, and pericyte death; reduced neutrophil stalling; and improved cerebrovascular reperfusion. Genetic analysis implicated altered TMEM16A expression in poor patient recovery from ischemic stroke. Thus, pericyte TMEM16A is a crucial regulator of cerebral capillary function and a potential therapeutic target for stroke and possibly other disorders of impaired microvascular flow, such as Alzheimer's disease and vascular dementia.
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Affiliation(s)
- Nils Korte
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, United Kingdom
| | - Zeki Ilkan
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Claire L. Pearson
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Thomas Pfeiffer
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, United Kingdom
| | - Prabhav Singhal
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, United Kingdom
| | - Jason R. Rock
- Center for Regenerative Medicine, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Huma Sethi
- Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | - Dipender Gill
- Department of Epidemiology and Biostatistics, St Mary’s Hospital, Imperial College London, London, United Kingdom
| | - David Attwell
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, United Kingdom
| | - Paolo Tammaro
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
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9
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Barzegar M, Stokes KY, Chernyshev O, Kelley RE, Alexander JS. The Role of the ACE2/MasR Axis in Ischemic Stroke: New Insights for Therapy. Biomedicines 2021; 9:1667. [PMID: 34829896 PMCID: PMC8615891 DOI: 10.3390/biomedicines9111667] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 11/02/2021] [Accepted: 11/08/2021] [Indexed: 12/15/2022] Open
Abstract
Ischemic stroke remains the leading cause of neurologically based morbidity and mortality. Current stroke treatment is limited to two classes of FDA-approved drugs: thrombolytic agents (tissue plasminogen activator (tPA)) and antithrombotic agents (aspirin and heparin), which have a narrow time-window (<4.5 h) for administration after onset of stroke symptoms. While thrombolytic agents restore perfusion, they carry serious risks for hemorrhage, and do not influence damage responses during reperfusion. Consequently, stroke therapies that can suppress deleterious effects of ischemic injury are desperately needed. Angiotensin converting enzyme-2 (ACE2) has been recently suggested to beneficially influence experimental stroke outcomes by converting the vasoconstrictor Ang II into the vasodilator Ang 1-7. In this review, we extensively discuss the protective functions of ACE2-Ang (1-7)-MasR axis of renin angiotensin system (RAS) in ischemic stroke.
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Affiliation(s)
- Mansoureh Barzegar
- Molecular and Cellular Physiology, Ochsner-LSU Health Sciences Center, Shreveport, LA 71130-3932, USA; (M.B.); (K.Y.S.)
| | - Karen Y. Stokes
- Molecular and Cellular Physiology, Ochsner-LSU Health Sciences Center, Shreveport, LA 71130-3932, USA; (M.B.); (K.Y.S.)
| | - Oleg Chernyshev
- Neurology, Ochsner-LSU Health Sciences Center, Shreveport, LA 71130-3932, USA; (O.C.); (R.E.K.)
| | - Roger E. Kelley
- Neurology, Ochsner-LSU Health Sciences Center, Shreveport, LA 71130-3932, USA; (O.C.); (R.E.K.)
| | - Jonathan S. Alexander
- Molecular and Cellular Physiology, Ochsner-LSU Health Sciences Center, Shreveport, LA 71130-3932, USA; (M.B.); (K.Y.S.)
- Neurology, Ochsner-LSU Health Sciences Center, Shreveport, LA 71130-3932, USA; (O.C.); (R.E.K.)
- Medicine, LSU Health Center, 1501 Kings Highway, Shreveport, LA 71130-3932, USA
- Oral and Maxillofacial Surgery, Ochsner-LSU Health Sciences Center, Shreveport, LA 71130-3932, USA
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10
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David H, Ughetto A, Gaudard P, Plawecki M, Paiyabhroma N, Zub E, Colson P, Richard S, Marchi N, Sicard P. Experimental Myocardial Infarction Elicits Time-Dependent Patterns of Vascular Hypoxia in Peripheral Organs and in the Brain. Front Cardiovasc Med 2021; 7:615507. [PMID: 33585582 PMCID: PMC7873295 DOI: 10.3389/fcvm.2020.615507] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 12/21/2020] [Indexed: 11/13/2022] Open
Abstract
Aims: Microvascular alterations occurring after myocardial infarction (MI) may represent a risk factor for multi-organ failure. Here we used in vivo photoacoustic (PA) imaging to track and define the changes in vascular oxygen saturation (sO2) occurring over time after experimental MI in multiple peripheral organs and in the brain. Methods and Results: Experimental MI was obtained in BALB/c mice by permanent ligation of the left anterior descending artery. PA imaging (Vevo LAZR-X) allowed tracking mouse-specific sO2 kinetics in the cardiac left ventricular (LV) anterior wall, brain, kidney, and liver at 4 h, 1 day, and 7 days post-MI. Here we reported a correlation between LV sO2 and longitudinal anterior myocardial strain after MI (r = −0.44, p < 0.0001, n = 96). Acute LV dysfunction was associated with global hypoxia, specifically a decrease in sO2 level in the brain (−5.9%), kidney (−6.4%), and liver (−7.3%) at 4 and 24 h post-MI. Concomitantly, a preliminary examination of capillary NG2DsRed pericytes indicated cell rarefication in the heart and kidney. While the cardiac tissue was persistently impacted, sO2 levels returned to pre-MI levels in the brain and in peripheral organs 7 days after MI. Conclusions: Collectively, our data indicate that experimental MI elicits precise trajectories of vascular hypoxia in peripheral organs and in the brain. PA imaging enabled the synchronous tracking of oxygenation in multiple organs and occurring post-MI, potentially enabling a translational diagnostic modality for the identification of vascular modifications in this disease setting.
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Affiliation(s)
- Hélène David
- INSERM, CNRS, Université de Montpellier, PHYMEDEXP, Montpellier, France.,Department of Anesthesiology and Critical Care Medicine, Arnaud de Villeneuve Hospital, CHU Montpellier, Montpellier, France
| | - Aurore Ughetto
- INSERM, CNRS, Université de Montpellier, PHYMEDEXP, Montpellier, France.,Department of Anesthesiology and Critical Care Medicine, Arnaud de Villeneuve Hospital, CHU Montpellier, Montpellier, France
| | - Philippe Gaudard
- INSERM, CNRS, Université de Montpellier, PHYMEDEXP, Montpellier, France.,Department of Anesthesiology and Critical Care Medicine, Arnaud de Villeneuve Hospital, CHU Montpellier, Montpellier, France
| | - Maëlle Plawecki
- INSERM, CNRS, Université de Montpellier, PHYMEDEXP, Montpellier, France.,CHU Lapeyronie, Département de Biochimie, Montpellier, France
| | | | - Emma Zub
- Cerebrovascular and Glia Research, Department of Neuroscience, Institute of Functional Genomics (UMR 5203 CNRS - U 1191 INSERM, University of Montpellier), Montpellier, France
| | - Pascal Colson
- Department of Anesthesiology and Critical Care Medicine, Arnaud de Villeneuve Hospital, CHU Montpellier, Montpellier, France.,Montpellier University, INSERM, CNRS, Institut de Génomique Fonctionnelle, Montpellier, France
| | - Sylvain Richard
- INSERM, CNRS, Université de Montpellier, PHYMEDEXP, Montpellier, France
| | - Nicola Marchi
- Cerebrovascular and Glia Research, Department of Neuroscience, Institute of Functional Genomics (UMR 5203 CNRS - U 1191 INSERM, University of Montpellier), Montpellier, France
| | - Pierre Sicard
- INSERM, CNRS, Université de Montpellier, PHYMEDEXP, Montpellier, France.,IPAM, BioCampus Montpellier, CNRS, INSERM, Université de Montpellier, Montpellier, France
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11
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Tanaka K, Matsumoto S, Yamada T, Yamasaki R, Suzuki M, Kido MA, Kira JI. Reduced Post-ischemic Brain Injury in Transient Receptor Potential Vanilloid 4 Knockout Mice. Front Neurosci 2020; 14:453. [PMID: 32477057 PMCID: PMC7235376 DOI: 10.3389/fnins.2020.00453] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Accepted: 04/14/2020] [Indexed: 12/25/2022] Open
Abstract
Background and Purpose In the acute phase of ischemia-reperfusion, hypoperfusion associated with ischemia and reperfusion in microvascular regions and disruption of the blood-brain barrier (BBB) contribute to post-ischemic brain injury. We aimed to clarify whether brain injury following transient middle cerebral artery occlusion (tMCAO) is ameliorated in Transient receptor potential vanilloid 4 knockout (Trpv4-/- ) mice. Methods tMCAO was induced in wild-type (WT) and Trpv4-/- mice aged 8-10 weeks. Ischemia-induced lesion volume was evaluated by 2,3,5-triphenyltetrazolium chloride staining at 24 h post-tMCAO. Tissue water content and Evans blue leakage in the ipsilateral hemisphere and a neurological score were evaluated at 48 h post-tMCAO. Transmission electron microscopy (TEM) was performed to assess the morphological changes in microvasculature in the ischemic lesions at 6 h post-tMCAO. Results Compared with WT mice, Trpv4-/- mice showed reduced ischemia-induced lesion volume and reduced water content and Evans blue leakage in the ipsilateral hemisphere alongside milder neurological symptoms. The loss of zonula occludens-1 and occludin proteins in the ipsilateral hemisphere was attenuated in Trpv4-/- mice. TEM revealed that parenchymal microvessels in the ischemic lesion were compressed and narrowed by the swollen endfeet of astrocytes in WT mice, but these effects were markedly ameliorated in Trpv4-/- mice. Conclusion The present results demonstrate that TRPV4 contributes to post-ischemic brain injury. The preserved microcirculation and BBB function shortly after reperfusion are the key neuroprotective roles of TRPV4 inhibition, which represents a promising target for the treatment of acute ischemic stroke.
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Affiliation(s)
- Koji Tanaka
- Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Shoji Matsumoto
- Department of Comprehensive Strokology, School of Medicine, Fujita Health University, Toyoake, Japan
| | - Takeshi Yamada
- Department of Neurology, Saiseikai Fukuoka General Hospital, Fukuoka, Japan
| | - Ryo Yamasaki
- Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Makoto Suzuki
- Department of Pharmacology, Division of Molecular Pharmacology, Jichi Medical University, Shimotsuke, Japan
| | - Mizuho A Kido
- Department of Anatomy and Physiology, Faculty of Medicine, Saga University, Saga, Japan
| | - Jun-Ichi Kira
- Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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12
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Asano N, Hishiyama S, Ishiyama T, Kotoda M, Matsukawa T. Effects of β 1-adrenergic receptor blockade on the cerebral microcirculation in the normal state and during global brain ischemia/reperfusion injury in rabbits. BMC Pharmacol Toxicol 2020; 21:13. [PMID: 32085806 PMCID: PMC7035637 DOI: 10.1186/s40360-020-0394-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Accepted: 02/16/2020] [Indexed: 11/27/2022] Open
Abstract
Background Although recent studies using experimental models of ischemic brain injury indicate that systemically-administered β1-blockers have potential protective effects on the cerebrovascular system, the precise mechanisms remain unclear. In addition to their cardiovascular effects, water-soluble β1-blockers can pass the blood–brain barrier and may exert their vascular action on cerebral microvessels. The aim of this study was to investigate the direct effects of β1-blockade on the cerebral microvasculature both in the normal state and ischemia/reperfusion state using the cranial window method. Methods The closed cranial window method was used to visualize the cerebral microcirculation and changes in the pial arteriole diameter in adult male rabbits. In the first experiment, various concentrations of the selective β1-blocker landiolol were administered into the cranial window to evaluate the dose-response. In the second experiment, the effect of β1-blockade on the brain during ischemic/reperfusion injury was investigated. Global brain ischemia/reperfusion was induced by clamping the brachiocephalic, left common carotid, and left subclavian arteries for 15 min. Either landiolol or artificial cerebrospinal fluid was infused 5 min after initiation of ischemia through 120 min after reperfusion. Pial arteriole diameter and hemodynamic and physiological parameters were recorded before ischemia, during ischemia, and 5, 10, 20, 40, 60, 80, 100, and 120 min after reperfusion. Results In the first experiment, topical administration of landiolol at higher concentrations produced slight pial arteriole dilation (10− 8 mol/L: 4.3 ± 3.4%, 10− 6 mol/L: 8.0 ± 5.8%, 10− 4 mol/L: 7.3 ± 4.0%). In the second experiment, the topical administration of landiolol significantly dilated the pial arteriole diameters during ischemia/reperfusion injury (ischemia: 30.6 ± 38.6%, 5 min: 47.3 ± 42.2%, 10 min: 47.8 ± 34.2%, 20 min: 38.0 ± 39.0%). There were no statistical differences in hemodynamic and physiological parameters between the landiolol and control groups. Conclusions The blockade of β1-adrenergic receptors induced significant vasodilation of pial arterioles during ischemia/reperfusion injury. By contrast, only a slight dilation of the arterioles was observed in the normal state, indicating that ischemic cerebral microvessels are more susceptible to the vasodilatory effect induced by selective blockade of β1-adrenergic receptors than normal microvessels.
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Affiliation(s)
- Nobumasa Asano
- Department of Anesthesiology, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan
| | - Sohei Hishiyama
- Department of Anesthesiology, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan
| | - Tadahiko Ishiyama
- Department of Anesthesiology, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan
| | - Masakazu Kotoda
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, 3 Blackfan Circle, Boston, MA, 02115, USA.
| | - Takashi Matsukawa
- Department of Anesthesiology, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan
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13
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Caporarello N, D’Angeli F, Cambria MT, Candido S, Giallongo C, Salmeri M, Lombardo C, Longo A, Giurdanella G, Anfuso CD, Lupo G. Pericytes in Microvessels: From "Mural" Function to Brain and Retina Regeneration. Int J Mol Sci 2019; 20:ijms20246351. [PMID: 31861092 PMCID: PMC6940987 DOI: 10.3390/ijms20246351] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/13/2019] [Accepted: 12/14/2019] [Indexed: 12/13/2022] Open
Abstract
Pericytes are branched cells located in the wall of capillary blood vessels that are found throughout the body, embedded within the microvascular basement membrane and wrapping endothelial cells, with which they establish a strong physical contact. Pericytes regulate angiogenesis, vessel stabilization, and contribute to the formation of both the blood-brain and blood-retina barriers by Angiopoietin-1/Tie-2, platelet derived growth factor (PDGF) and transforming growth factor (TGF) signaling pathways, regulating pericyte-endothelial cell communication. Human pericytes that have been cultured for a long period give rise to multilineage progenitor cells and exhibit mesenchymal stem cell (MSC) features. We focused our attention on the roles of pericytes in brain and ocular diseases. In particular, pericyte involvement in brain ischemia, brain tumors, diabetic retinopathy, and uveal melanoma is described. Several molecules, such as adenosine and nitric oxide, are responsible for pericyte shrinkage during ischemia-reperfusion. Anti-inflammatory molecules, such as IL-10, TGFβ, and MHC-II, which are increased in glioblastoma-activated pericytes, are responsible for tumor growth. As regards the eye, pericytes play a role not only in ocular vessel stabilization, but also as a stem cell niche that contributes to regenerative processes in diabetic retinopathy. Moreover, pericytes participate in melanoma cell extravasation and the genetic ablation of the PDGF receptor reduces the number of pericytes and aberrant tumor microvessel formation with important implications for therapy efficacy. Thanks to their MSC features, pericytes could be considered excellent candidates to promote nervous tissue repair and for regenerative medicine.
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Affiliation(s)
- Nunzia Caporarello
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA;
| | - Floriana D’Angeli
- Section of Medical Biochemistry, Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, 95123 Catania, Italy; (F.D.); (M.T.C.); (A.L.); (G.G.)
| | - Maria Teresa Cambria
- Section of Medical Biochemistry, Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, 95123 Catania, Italy; (F.D.); (M.T.C.); (A.L.); (G.G.)
| | - Saverio Candido
- Section of General and Clinical Pathology and Oncology, Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, 95123 Catania, Italy;
| | - Cesarina Giallongo
- Section of Haematology, Department of General Surgery and Medical-Surgical Specialties, University of Catania, 95123 Catania, Italy;
| | - Mario Salmeri
- Section of Microbiology, Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, 95123 Catania, Italy; (M.S.); (C.L.)
| | - Cinzia Lombardo
- Section of Microbiology, Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, 95123 Catania, Italy; (M.S.); (C.L.)
| | - Anna Longo
- Section of Medical Biochemistry, Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, 95123 Catania, Italy; (F.D.); (M.T.C.); (A.L.); (G.G.)
| | - Giovanni Giurdanella
- Section of Medical Biochemistry, Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, 95123 Catania, Italy; (F.D.); (M.T.C.); (A.L.); (G.G.)
| | - Carmelina Daniela Anfuso
- Section of Medical Biochemistry, Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, 95123 Catania, Italy; (F.D.); (M.T.C.); (A.L.); (G.G.)
- Correspondence: (G.L.); (C.D.A.); Tel.: +39-095-4781158 (G.L.); +39-095-4781170 (C.D.A.)
| | - Gabriella Lupo
- Section of Medical Biochemistry, Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, 95123 Catania, Italy; (F.D.); (M.T.C.); (A.L.); (G.G.)
- Correspondence: (G.L.); (C.D.A.); Tel.: +39-095-4781158 (G.L.); +39-095-4781170 (C.D.A.)
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14
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Vendel E, Rottschäfer V, de Lange ECM. The need for mathematical modelling of spatial drug distribution within the brain. Fluids Barriers CNS 2019; 16:12. [PMID: 31092261 PMCID: PMC6521438 DOI: 10.1186/s12987-019-0133-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 04/19/2019] [Indexed: 12/17/2022] Open
Abstract
The blood brain barrier (BBB) is the main barrier that separates the blood from the brain. Because of the BBB, the drug concentration-time profile in the brain may be substantially different from that in the blood. Within the brain, the drug is subject to distributional and elimination processes: diffusion, bulk flow of the brain extracellular fluid (ECF), extra-intracellular exchange, bulk flow of the cerebrospinal fluid (CSF), binding and metabolism. Drug effects are driven by the concentration of a drug at the site of its target and by drug-target interactions. Therefore, a quantitative understanding is needed of the distribution of a drug within the brain in order to predict its effect. Mathematical models can help in the understanding of drug distribution within the brain. The aim of this review is to provide a comprehensive overview of system-specific and drug-specific properties that affect the local distribution of drugs in the brain and of currently existing mathematical models that describe local drug distribution within the brain. Furthermore, we provide an overview on which processes have been addressed in these models and which have not. Altogether, we conclude that there is a need for a more comprehensive and integrated model that fills the current gaps in predicting the local drug distribution within the brain.
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Affiliation(s)
- Esmée Vendel
- Mathematical Institute, Leiden University, Niels Bohrweg 1, 2333CA, Leiden, The Netherlands
| | - Vivi Rottschäfer
- Mathematical Institute, Leiden University, Niels Bohrweg 1, 2333CA, Leiden, The Netherlands
| | - Elizabeth C M de Lange
- Leiden Academic Centre for Drug Research, Einsteinweg 55, 2333CC, Leiden, The Netherlands.
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15
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Li L, Poloyac SM, Watkins SC, St. Croix CM, Alexander H, Gibson GA, Loughran PA, Kirisci L, Clark RSB, Kochanek PM, Vazquez AL, Manole MD. Cerebral microcirculatory alterations and the no-reflow phenomenon in vivo after experimental pediatric cardiac arrest. J Cereb Blood Flow Metab 2019; 39:913-925. [PMID: 29192562 PMCID: PMC6501505 DOI: 10.1177/0271678x17744717] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 09/29/2017] [Accepted: 10/25/2017] [Indexed: 01/02/2023]
Abstract
Decreased cerebral blood flow (CBF) after cardiac arrest (CA) contributes to secondary ischemic injury in infants and children. We previously reported cortical hypoperfusion with tissue hypoxia early in a pediatric rat model of asphyxial CA. In order to identify specific alterations as potential therapeutic targets to improve cortical hypoperfusion post-CA, we characterize the CBF alterations at the cortical microvascular level in vivo using multiphoton microscopy. We hypothesize that microvascular constriction and disturbances of capillary red blood cell (RBC) flow contribute to cortical hypoperfusion post-CA. After resuscitation from 9 min asphyxial CA, transient dilation of capillaries and venules at 5 min was followed by pial arteriolar constriction at 30 and 60 min (19.6 ± 1.3, 19.3 ± 1.2 µm at 30, 60 min vs. 22.0 ± 1.2 µm at baseline, p < 0.05). At the capillary level, microcirculatory disturbances were highly heterogeneous, with RBC stasis observed in 25.4% of capillaries at 30 min post-CA. Overall, the capillary plasma mean transit time was increased post-CA by 139.7 ± 51.5%, p < 0.05. In conclusion, pial arteriolar constriction, the no-reflow phenomenon and increased plasma transit time were observed post-CA. Our results detail the microvascular disturbances in a pediatric asphyxial CA model and provide a powerful platform for assessing specific vascular-targeted therapies.
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Affiliation(s)
- Lingjue Li
- Center of Clinical Pharmaceutical
Sciences,
University
of Pittsburgh, PA, USA
- School of Pharmacy,
University
of Pittsburgh, PA, USA
| | - Samuel M Poloyac
- Center of Clinical Pharmaceutical
Sciences,
University
of Pittsburgh, PA, USA
- School of Pharmacy,
University
of Pittsburgh, PA, USA
| | - Simon C Watkins
- Center for Biologic Imaging,
University
of Pittsburgh, PA, USA
| | | | - Henry Alexander
- Safar Center for Resuscitation Research,
University
of Pittsburgh, PA, USA
| | | | | | | | - Robert SB Clark
- Safar Center for Resuscitation Research,
University
of Pittsburgh, PA, USA
- Department of Critical Care Medicine,
University
of Pittsburgh, PA, USA
| | - Patrick M Kochanek
- Safar Center for Resuscitation Research,
University
of Pittsburgh, PA, USA
- Department of Critical Care Medicine,
University
of Pittsburgh, PA, USA
- Department of Pediatrics,
University
of Pittsburgh, PA, USA
| | | | - Mioara D Manole
- Safar Center for Resuscitation Research,
University
of Pittsburgh, PA, USA
- Department of Critical Care Medicine,
University
of Pittsburgh, PA, USA
- Department of Pediatrics,
University
of Pittsburgh, PA, USA
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16
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Erdener ŞE, Tang J, Sajjadi A, Kılıç K, Kura S, Schaffer CB, Boas DA. Spatio-temporal dynamics of cerebral capillary segments with stalling red blood cells. J Cereb Blood Flow Metab 2019; 39:886-900. [PMID: 29168661 PMCID: PMC6501506 DOI: 10.1177/0271678x17743877] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Optical coherence tomography (OCT) allows label-free imaging of red blood cell (RBC) flux within capillaries with high spatio-temporal resolution. In this study, we utilized time-series OCT-angiography to demonstrate interruptions in capillary RBC flux in mouse brain in vivo. We noticed ∼7.5% of ∼200 capillaries had at least one stall in awake mice with chronic windows during a 9-min recording. At any instant, ∼0.45% of capillaries were stalled. Average stall duration was ∼15 s but could last over 1 min. Stalls were more frequent and longer lasting in acute window preparations. Further, isoflurane anesthesia in chronic preparations caused an increase in the number of stalls. In repeated imaging, the same segments had a tendency to stall again over a period of one month. In awake animals, functional stimulation decreased the observance of stalling events. Stalling segments were located distally, away from the first couple of arteriolar-side capillary branches and their average RBC and plasma velocities were lower than nonstalling capillaries within the same region. This first systematic analysis of capillary RBC stalls in the brain, enabled by rapid and continuous volumetric imaging of capillaries with OCT-angiography, will lead to future investigations of the potential role of stalling events in cerebral pathologies.
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Affiliation(s)
- Şefik Evren Erdener
- 1 Optics Division, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Jianbo Tang
- 1 Optics Division, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Amir Sajjadi
- 1 Optics Division, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Kıvılcım Kılıç
- 2 Neurophotonics Center, Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Sreekanth Kura
- 1 Optics Division, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Chris B Schaffer
- 3 Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA
| | - David A Boas
- 1 Optics Division, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA.,2 Neurophotonics Center, Department of Biomedical Engineering, Boston University, Boston, MA, USA
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17
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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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18
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Ata MM, Ashour AS, Guo Y, Elnaby MMA. Centroid tracking and velocity measurement of white blood cell in video. Health Inf Sci Syst 2018; 6:20. [PMID: 30425827 DOI: 10.1007/s13755-018-0060-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 10/16/2018] [Indexed: 11/25/2022] Open
Abstract
Automated blood cells tracking system has a vital role as the tracking process reflects the blood cell characteristics and indicates several diseases. Blood cells tracking is challenging due to the non-rigid shapes of the blood cells, and the variability in their videos along with the existence of different moving objects in the blood. To tackle such challenges, we proposed a green star based centroid (GSBC) moving white blood cell (WBC) tracking algorithm to measure its velocity and draw its trajectory. The proposed cell tracking system consists of two stages, namely WBC detection and blob analysis, and fine tuning the tracking process by determine the centroid of the WBC, and mark the centroid for further fine tracking and to exclude the bacteria from the bounding box. Furthermore, the speed and the trajectory of the WBC motion are recorded and plotted. In the experiments, an optical flow technique is compared with the proposed tracking system showing the superiority of the proposed system as the optical flow method failed to track the WBC. The proposed system identified the WBC accurately, while the optical flow identified all other objects lead to its disability to track the WBC.
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Affiliation(s)
- Mohamed Maher Ata
- Misr Higher Institute of Engineering and Technology, Mansoura, Egypt
| | - Amira S Ashour
- 2Department of Electronics and Electrical Communications Engineering, Faculty of Engineering, Tanta University, Tanta, Egypt
| | - Yanhui Guo
- 3Department of Computer Science, University of Illinois at Springfield, Springfield, IL USA
| | - Mustafa M Abd Elnaby
- 2Department of Electronics and Electrical Communications Engineering, Faculty of Engineering, Tanta University, Tanta, Egypt
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19
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Engedal TS, Hjort N, Hougaard KD, Simonsen CZ, Andersen G, Mikkelsen IK, Boldsen JK, Eskildsen SF, Hansen MB, Angleys H, Jespersen SN, Pedraza S, Cho TH, Serena J, Siemonsen S, Thomalla G, Nighoghossian N, Fiehler J, Mouridsen K, Østergaard L. Transit time homogenization in ischemic stroke - A novel biomarker of penumbral microvascular failure? J Cereb Blood Flow Metab 2018; 38:2006-2020. [PMID: 28758524 PMCID: PMC6259320 DOI: 10.1177/0271678x17721666] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Cerebral ischemia causes widespread capillary no-flow in animal studies. The extent of microvascular impairment in human stroke, however, is unclear. We examined how acute intra-voxel transit time characteristics and subsequent recanalization affect tissue outcome on follow-up MRI in a historic cohort of 126 acute ischemic stroke patients. Based on perfusion-weighted MRI data, we characterized voxel-wise transit times in terms of their mean transit time (MTT), standard deviation (capillary transit time heterogeneity - CTH), and the CTH:MTT ratio (relative transit time heterogeneity), which is expected to remain constant during changes in perfusion pressure in a microvasculature consisting of passive, compliant vessels. To aid data interpretation, we also developed a computational model that relates graded microvascular failure to changes in these parameters. In perfusion-diffusion mismatch tissue, prolonged mean transit time (>5 seconds) and very low cerebral blood flow (≤6 mL/100 mL/min) was associated with high risk of infarction, largely independent of recanalization status. In the remaining mismatch region, low relative transit time heterogeneity predicted subsequent infarction if recanalization was not achieved. Our model suggested that transit time homogenization represents capillary no-flow. Consistent with this notion, low relative transit time heterogeneity values were associated with lower cerebral blood volume. We speculate that low RTH may represent a novel biomarker of penumbral microvascular failure.
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Affiliation(s)
- Thorbjørn S Engedal
- 1 Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University, Aarhus University Hospital, Aarhus C, Denmark.,2 Department of Neuroradiology, Aarhus University Hospital, Nørrebrogade 44, 8000 Aarhus C, Denmark
| | - Niels Hjort
- 3 Department of Neurology Aarhus University Hospital, Aarhus C, Denmark
| | | | - Claus Z Simonsen
- 3 Department of Neurology Aarhus University Hospital, Aarhus C, Denmark
| | - Grethe Andersen
- 3 Department of Neurology Aarhus University Hospital, Aarhus C, Denmark
| | - Irene Klærke Mikkelsen
- 1 Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University, Aarhus University Hospital, Aarhus C, Denmark
| | - Jens K Boldsen
- 1 Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University, Aarhus University Hospital, Aarhus C, Denmark
| | - Simon F Eskildsen
- 1 Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University, Aarhus University Hospital, Aarhus C, Denmark
| | - Mikkel B Hansen
- 1 Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University, Aarhus University Hospital, Aarhus C, Denmark
| | - Hugo Angleys
- 1 Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University, Aarhus University Hospital, Aarhus C, Denmark
| | - Sune N Jespersen
- 1 Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University, Aarhus University Hospital, Aarhus C, Denmark.,4 Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | | | - Tae H Cho
- 6 Hospices Civils de Lyon, Lyon, France
| | | | | | - Götz Thomalla
- 7 University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | | | - Jens Fiehler
- 7 University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Kim Mouridsen
- 1 Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University, Aarhus University Hospital, Aarhus C, Denmark
| | - Leif Østergaard
- 1 Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University, Aarhus University Hospital, Aarhus C, Denmark.,2 Department of Neuroradiology, Aarhus University Hospital, Nørrebrogade 44, 8000 Aarhus C, Denmark
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20
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Cheng J, Korte N, Nortley R, Sethi H, Tang Y, Attwell D. Targeting pericytes for therapeutic approaches to neurological disorders. Acta Neuropathol 2018; 136:507-523. [PMID: 30097696 PMCID: PMC6132947 DOI: 10.1007/s00401-018-1893-0] [Citation(s) in RCA: 152] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 07/30/2018] [Accepted: 07/31/2018] [Indexed: 12/13/2022]
Abstract
Many central nervous system diseases currently lack effective treatment and are often associated with defects in microvascular function, including a failure to match the energy supplied by the blood to the energy used on neuronal computation, or a breakdown of the blood–brain barrier. Pericytes, an under-studied cell type located on capillaries, are of crucial importance in regulating diverse microvascular functions, such as angiogenesis, the blood–brain barrier, capillary blood flow and the movement of immune cells into the brain. They also form part of the “glial” scar isolating damaged parts of the CNS, and may have stem cell-like properties. Recent studies have suggested that pericytes play a crucial role in neurological diseases, and are thus a therapeutic target in disorders as diverse as stroke, traumatic brain injury, migraine, epilepsy, spinal cord injury, diabetes, Huntington’s disease, Alzheimer’s disease, diabetes, multiple sclerosis, glioma, radiation necrosis and amyotrophic lateral sclerosis. Here we report recent advances in our understanding of pericyte biology and discuss how pericytes could be targeted to develop novel therapeutic approaches to neurological disorders, by increasing blood flow, preserving blood–brain barrier function, regulating immune cell entry to the CNS, and modulating formation of blood vessels in, and the glial scar around, damaged regions.
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Affiliation(s)
- Jinping Cheng
- Department of Neurology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107 Yan Jiang Xi Rd, Guangzhou, 510120, People's Republic of China
| | - Nils Korte
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Ross Nortley
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Huma Sethi
- Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, Queen Square, London, WC1N 3BG, UK
| | - Yamei Tang
- Department of Neurology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107 Yan Jiang Xi Rd, Guangzhou, 510120, People's Republic of China.
| | - David Attwell
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.
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21
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O'Farrell FM, Mastitskaya S, Hammond-Haley M, Freitas F, Wah WR, Attwell D. Capillary pericytes mediate coronary no-reflow after myocardial ischaemia. eLife 2017; 6:29280. [PMID: 29120327 PMCID: PMC5705208 DOI: 10.7554/elife.29280] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 11/08/2017] [Indexed: 12/22/2022] Open
Abstract
After cardiac ischaemia, a prolonged decrease of coronary microvascular perfusion often occurs even after flow is restored in an upstream artery. This 'no-reflow' phenomenon worsens patient prognosis. In the brain, after stroke, a similar post-ischaemic 'no-reflow' has been attributed to capillary constriction by contractile pericytes. We now show that occlusion of a rat coronary artery, followed by reperfusion, blocks 40% of cardiac capillaries and halves perfused blood volume within the affected region. Capillary blockages colocalised strongly with pericytes, where capillary diameter was reduced by 37%. The pericyte relaxant adenosine increased capillary diameter by 21% at pericyte somata, decreased capillary block by 25% and increased perfusion volume by 57%. Thus, cardiac pericytes constrict coronary capillaries and reduce microvascular blood flow after ischaemia, despite re-opening of the culprit artery. Cardiac pericytes are therefore a novel therapeutic target in ischaemic heart disease. Heart attacks occur when one of the arteries supplying blood to the heart muscle becomes blocked, usually by a blood clot. Doctors unblock the artery and insert an expanding metal cage called a stent to keep it unblocked. This restores blood flow through the artery. Unfortunately, blood flow often does not return to smaller downstream blood vessels called capillaries. This can lead to further damage to the heart. Scientists have not been able to find a way to reliably open up those capillaries after a heart attack because it is not clear exactly what is keeping them closed. Muscle-like cells called pericytes, which wrap around the capillaries, are one possible culprit for the blockages. Pericytes narrow capillaries in the brain after stroke in animal experiments. These cells are also present on heart capillaries, but scientists do not know much about them. Now, O’Farrell, Mastitskaya, Hammond-Haley et al. show that pericytes are partly responsible for limiting blood flow in capillaries after a heart attack in rats. In the experiments, blood flow through an artery feeding the hearts of anaesthetized rats was restricted, simulating a heart attack. After the blood flow was later restored, 40% of the animal’s capillaries remained blocked. Many blockages occurred near pericytes that had narrowed the capillary preventing blood flow. Treating the rats with a drug called adenosine, which relaxes the pericytes, reduced capillary blockages and increased blood flow in the heart. Although adenosine could help to restore blood flow in the capillaries after a heart attack, it may also relax muscles around arteries and lower blood pressure, and so it may not be an ideal treatment. More studies are needed to determine whether drugs that target only the pericytes could complement existing heart attack treatments that unblock the arteries. If these studies are successful, pericyte-targeting drugs might prevent serious complications after a heart attack, including heart failure, heart rhythm abnormalities and future heart attacks.
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Affiliation(s)
- Fergus M O'Farrell
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Svetlana Mastitskaya
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Matthew Hammond-Haley
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Felipe Freitas
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Wen Rui Wah
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - David Attwell
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
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22
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3D morphological analysis of the mouse cerebral vasculature: Comparison of in vivo and ex vivo methods. PLoS One 2017; 12:e0186676. [PMID: 29053753 PMCID: PMC5650181 DOI: 10.1371/journal.pone.0186676] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2016] [Accepted: 10/05/2017] [Indexed: 02/06/2023] Open
Abstract
Ex vivo 2-photon fluorescence microscopy (2PFM) with optical clearing enables vascular imaging deep into tissue. However, optical clearing may also produce spherical aberrations if the objective lens is not index-matched to the clearing material, while the perfusion, clearing, and fixation procedure may alter vascular morphology. We compared in vivo and ex vivo 2PFM in mice, focusing on apparent differences in microvascular signal and morphology. Following in vivo imaging, the mice (four total) were perfused with a fluorescent gel and their brains fructose-cleared. The brain regions imaged in vivo were imaged ex vivo. Vessels were segmented in both images using an automated tracing algorithm that accounts for the spatially varying PSF in the ex vivo images. This spatial variance is induced by spherical aberrations caused by imaging fructose-cleared tissue with a water-immersion objective. Alignment of the ex vivo image to the in vivo image through a non-linear warping algorithm enabled comparison of apparent vessel diameter, as well as differences in signal. Shrinkage varied as a function of diameter, with capillaries rendered smaller ex vivo by 13%, while penetrating vessels shrunk by 34%. The pial vasculature attenuated in vivo microvascular signal by 40% 300 μm below the tissue surface, but this effect was absent ex vivo. On the whole, ex vivo imaging was found to be valuable for studying deep cortical vasculature.
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23
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Animal models of ischaemic stroke and characterisation of the ischaemic penumbra. Neuropharmacology 2017; 134:169-177. [PMID: 28923277 DOI: 10.1016/j.neuropharm.2017.09.022] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 09/08/2017] [Accepted: 09/13/2017] [Indexed: 02/07/2023]
Abstract
Over the past forty years, animal models of focal cerebral ischaemia have allowed us to identify the critical cerebral blood flow thresholds responsible for irreversible cell death, electrical failure, inhibition of protein synthesis, energy depletion and thereby the lifespan of the potentially salvageable penumbra. They have allowed us to understand the intricate biochemical and molecular mechanisms within the 'ischaemic cascade' that initiate cell death in the first minutes, hours and days following stroke. Models of permanent, transient middle cerebral artery occlusion and embolic stroke have been developed each with advantages and limitations when trying to model the complex heterogeneous nature of stroke in humans. Yet despite these advances in understanding the pathophysiological mechanisms of stroke-induced cell death with numerous targets identified and drugs tested, a lack of translation to the clinic has hampered pre-clinical stroke research. With recent positive clinical trials of endovascular thrombectomy in acute ischaemic stroke the stroke community has been reinvigorated, opening up the potential for future translation of adjunctive treatments that can be given alongside thrombectomy/thrombolysis. This review discusses the major animal models of focal cerebral ischaemia highlighting their advantages and limitations. Acute imaging is crucial in longitudinal pre-clinical stroke studies in order to identify the influence of acute therapies on tissue salvage over time. Therefore, the methods of identifying potentially salvageable ischaemic penumbra are discussed. This article is part of the Special Issue entitled 'Cerebral Ischemia'.
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24
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Shimbo D, Abumiya T, Kurisu K, Osanai T, Shichinohe H, Nakayama N, Kazumata K, Nakamura H, Shimuzu H, Houkin K. Superior Microvascular Perfusion of Infused Liposome-Encapsulated Hemoglobin Prior to Reductions in Infarctions after Transient Focal Cerebral Ischemia. J Stroke Cerebrovasc Dis 2017; 26:2994-3003. [PMID: 28843805 DOI: 10.1016/j.jstrokecerebrovasdis.2017.07.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 07/20/2017] [Accepted: 07/25/2017] [Indexed: 10/19/2022] Open
Abstract
BACKGROUND The development of cerebral infarction after transient ischemia is attributed to postischemic delayed hypoperfusion in the microvascular region. In the present study, we assessed the microvascular perfusion capacity of infused liposome-encapsulated hemoglobin (LEH) in a therapeutic approach for transient middle cerebral artery occlusion (tMCAO). METHODS Two-hour middle cerebral artery occlusion rats were immediately subjected to intra-arterial infusion of LEH (LEH group) or saline (vehicle group) or no treatment (control group), and then to recanalization. Neurological findings, infarct and edema progression, microvascular endothelial dysfunction, and inflammatory reactions were compared between the 3 groups after 24 hours of reperfusion. Microvascular perfusion in the early phase of reperfusion was evaluated by hemoglobin immunohistochemistry and transmission electron microscopy. RESULTS The LEH group achieved significantly better results in all items evaluated than the other groups. Hemoglobin immunohistochemistry revealed that the number of hemoglobin-positive microvessels was significantly greater in the LEH group than in the other groups (P < .01), with microvascular perfusion being more likely in narrow microvessels (≤5 µm in diameter). An electron microscopic examination revealed that microvessels in the control group were compressed and narrowed by swollen astrocyte end-feet, whereas those in the LEH group had a less deformed appearance and contained LEH particles and erythrocytes. CONCLUSION The results of the present study demonstrated that the infusion of LEH reduced infarctions after tMCAO with more hemoglobin-positive and less deformed microvessels at the early phase of reperfusion, suggesting that the superiority of the microvascular perfusion of LEH mediates its neuroprotective effects.
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Affiliation(s)
- Daisuke Shimbo
- Department of Neurosurgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Takeo Abumiya
- Department of Neurosurgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
| | - Kota Kurisu
- Department of Neurosurgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Toshiya Osanai
- Department of Neurosurgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Hideo Shichinohe
- Department of Neurosurgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Naoki Nakayama
- Department of Neurosurgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Ken Kazumata
- Department of Neurosurgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Hideki Nakamura
- Department of Dermatology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Hiroshi Shimuzu
- Department of Dermatology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Kiyohiro Houkin
- Department of Neurosurgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan
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25
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Shintani N, Ishiyama T, Kotoda M, Asano N, Sessler DI, Matsukawa T. The effects of Y-27632 on pial microvessels during global brain ischemia and reperfusion in rabbits. BMC Anesthesiol 2017; 17:38. [PMID: 28270098 PMCID: PMC5341179 DOI: 10.1186/s12871-017-0331-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 02/24/2017] [Indexed: 11/29/2022] Open
Abstract
Background Global brain ischemia-reperfusion during propofol anesthesia provokes persistent cerebral pial constriction. Constriction is likely mediated by Rho-kinase. Cerebral vasoconstriction possibly exacerbates ischemic brain injury. Because Y-27632 is a potent Rho-kinase inhibitor, it should be necessary to evaluate its effects on cerebral pial vessels during ischemia—reperfusion period. We therefore tested the hypotheses that Y-27632 dilates cerebral pial arterioles after the ischemia-reperfusion injury, and evaluated the time-course of cerebral pial arteriolar status after the ischemia-reperfusion. Methods Japanese white rabbits were anesthetized with propofol, and a closed cranial window inserted over the left hemisphere. Global brain ischemia was produced by clamping the brachiocephalic, left common carotid, and left subclavian arteries for 15 min. Rabbits were assigned to cranial window perfusion with: (1) artificial cerebrospinal fluid (Control group, n = 7); (2) topical infusion of Y-27632 10−6 mol · L−1 for 30 min before the initiation of global brain ischemia (Pre group, n = 7); (3) topical infusion of Y-27632 10−6 mol · L−1 starting 30 min before ischemia and continuing throughout the study period (Continuous group, n = 7); and, (4) topical infusion of Y-27632 10−6 mol · L−1 starting 10 min after the ischemia and continuing until the end of the study (Post group, n = 7). Cerebral pial arterial and venule diameters were recorded 30 min before ischemia, just before arterial clamping, 10 min after clamping, and 5, 10, 20, 40, 60, 80, 100, and 120 min after unclamping. Results Mean arterial blood pressure and blood glucose concentration increased significantly after global brain ischemia except in the Continuous group. In the Pre and Continuous groups, topical application of Y-27632 produced dilation of large (mean 18–19%) and small (mean; 25–29%) pial arteries, without apparent effect on venules. Compared with the Control and Pre groups, arterioles were significantly dilated during the reperfusion period in the Continuous and Post groups (mean at 120 min: 5–8% in large arterioles and 11–12% in small arterioles). Conclusions Y-27632 dilated cerebral pial arterioles during reperfusion. Y-27632 may enhance recovery from ischemia by preventing arteriolar vasoconstriction during reperfusion.
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Affiliation(s)
- Noriyuki Shintani
- Surgical Center, University of Yamanashi Hospital, 1110 Shimokato, Chuo, 409-3898, Yamanashi, Japan.
| | - Tadahiko Ishiyama
- Surgical Center, University of Yamanashi Hospital, 1110 Shimokato, Chuo, 409-3898, Yamanashi, Japan
| | - Masakazu Kotoda
- Department of Anesthesiology, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, 409-3898, Yamanashi, Japan
| | - Nobumasa Asano
- Department of Anesthesiology, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, 409-3898, Yamanashi, Japan
| | - Daniel I Sessler
- Department of Outcomes Research, Cleveland Clinic, Anesthesiology Institute, Cleveland, OH, USA
| | - Takashi Matsukawa
- Department of Anesthesiology, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, 409-3898, Yamanashi, Japan
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26
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Siegel JS, Snyder AZ, Ramsey L, Shulman GL, Corbetta M. The effects of hemodynamic lag on functional connectivity and behavior after stroke. J Cereb Blood Flow Metab 2016; 36:2162-2176. [PMID: 26661223 PMCID: PMC5363662 DOI: 10.1177/0271678x15614846] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 09/02/2015] [Accepted: 10/06/2015] [Indexed: 01/22/2023]
Abstract
Stroke disrupts the brain's vascular supply, not only within but also outside areas of infarction. We investigated temporal delays (lag) in resting state functional magnetic resonance imaging signals in 130 stroke patients scanned two weeks, three months and 12 months post stroke onset. Thirty controls were scanned twice at an interval of three months. Hemodynamic lag was determined using cross-correlation with the global gray matter signal. Behavioral performance in multiple domains was assessed in all patients. Regional cerebral blood flow and carotid patency were assessed in subsets of the cohort using arterial spin labeling and carotid Doppler ultrasonography. Significant hemodynamic lag was observed in 30% of stroke patients sub-acutely. Approximately 10% of patients showed lag at one-year post-stroke. Hemodynamic lag corresponded to gross aberrancy in functional connectivity measures, performance deficits in multiple domains and local and global perfusion deficits. Correcting for lag partially normalized abnormalities in measured functional connectivity. Yet post-stroke FC-behavior relationships in the motor and attention systems persisted even after hemodynamic delays were corrected. Resting state fMRI can reliably identify areas of hemodynamic delay following stroke. Our data reveal that hemodynamic delay is common sub-acutely, alters functional connectivity, and may be of clinical importance.
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Affiliation(s)
- Joshua S Siegel
- Departments of Neurology, Washington University School of Medicine, Washington University, St. Louis, MO, USA
| | - Abraham Z Snyder
- Departments of Neurology, Washington University School of Medicine, Washington University, St. Louis, MO, USA.,Mallinckrodt Institute of Radiology, Washington University School of Medicine, Washington University, St. Louis, MO, USA
| | - Lenny Ramsey
- Departments of Neurology, Washington University School of Medicine, Washington University, St. Louis, MO, USA
| | - Gordon L Shulman
- Departments of Neurology, Washington University School of Medicine, Washington University, St. Louis, MO, USA
| | - Maurizio Corbetta
- Departments of Neurology, Washington University School of Medicine, Washington University, St. Louis, MO, USA.,Mallinckrodt Institute of Radiology, Washington University School of Medicine, Washington University, St. Louis, MO, USA.,Anatomy & Neurobiology at Washington University School of Medicine, Washington University, St. Louis, MO, USA
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27
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Stokum JA, Gerzanich V, Simard JM. Molecular pathophysiology of cerebral edema. J Cereb Blood Flow Metab 2016; 36:513-38. [PMID: 26661240 PMCID: PMC4776312 DOI: 10.1177/0271678x15617172] [Citation(s) in RCA: 357] [Impact Index Per Article: 44.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 10/21/2015] [Accepted: 10/22/2015] [Indexed: 12/25/2022]
Abstract
Advancements in molecular biology have led to a greater understanding of the individual proteins responsible for generating cerebral edema. In large part, the study of cerebral edema is the study of maladaptive ion transport. Following acute CNS injury, cells of the neurovascular unit, particularly brain endothelial cells and astrocytes, undergo a program of pre- and post-transcriptional changes in the activity of ion channels and transporters. These changes can result in maladaptive ion transport and the generation of abnormal osmotic forces that, ultimately, manifest as cerebral edema. This review discusses past models and current knowledge regarding the molecular and cellular pathophysiology of cerebral edema.
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Affiliation(s)
- Jesse A Stokum
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, USA
| | - Volodymyr Gerzanich
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, USA
| | - J Marc Simard
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, USA Department of Pathology, University of Maryland School of Medicine, Baltimore, USA Department of Physiology, University of Maryland School of Medicine, Baltimore, USA
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28
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Attwell D, Mishra A, Hall CN, O'Farrell FM, Dalkara T. What is a pericyte? J Cereb Blood Flow Metab 2016; 36:451-5. [PMID: 26661200 PMCID: PMC4759679 DOI: 10.1177/0271678x15610340] [Citation(s) in RCA: 420] [Impact Index Per Article: 52.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 09/10/2015] [Indexed: 01/06/2023]
Abstract
Pericytes, spatially isolated contractile cells on capillaries, have been reported to control cerebral blood flow physiologically, and to limit blood flow after ischaemia by constricting capillaries and then dying. Paradoxically, a recent paper dismisses the idea of pericytes controlling cerebral blood flow, despite confirming earlier data showing a role for pericytes. We show that these discrepancies are apparent rather than real, and depend on the new paper defining pericytes differently from previous reports. An objective definition of different sub-classes of pericyte along the capillary bed is needed to develop novel therapeutic approaches for stroke and disorders caused by pericyte malfunction.
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Affiliation(s)
- David Attwell
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, UK
| | - Anusha Mishra
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, UK
| | - Catherine N Hall
- School of Psychology, University of Sussex, Falmer, Brighton, UK
| | - Fergus M O'Farrell
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, UK
| | - Turgay Dalkara
- Institute of Neurological Sciences and Psychiatry, and Department of Neurology, Faculty of Medicine, Hacettepe University, Sihhiye, Ankara, Turkey
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29
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Garrigue P, Giacomino L, Bucci C, Muzio V, Filannino MA, Sabatier F, Dignat-George F, Pisano P, Guillet B. Single photon emission computed tomography imaging of cerebral blood flow, blood–brain barrier disruption, and apoptosis time course after focal cerebral ischemia in rats. Int J Stroke 2015; 11:117-26. [DOI: 10.1177/1747493015607516] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Background Cerebral ischemia is a leading cause of disability worldwide and no other effective therapy has been validated to date than intravenous thrombolysis. In this context, many preclinical models have been developed and recent advances in preclinical imaging represent promising tools. Thus, we proposed here to characterize in vivo time profiles of cerebral blood flow, blood–brain barrier disruption and apoptosis following a transient middle cerebral artery occlusion in rats using SPECT/CT imaging. Methods Rats underwent a 1-h middle cerebral artery occlusion followed by reperfusion. Cerebral blood flow, blood–brain barrier disruption and apoptosis were evaluated by SPECT/CT imaging using respectively 99mTc-HMPAO, 99mTc-DTPA and the experimental 99mTc-Annexin V-128, up to 14 days after middle cerebral artery occlusion. Histological evaluation of apoptosis has been performed using TUNEL method to validate the 99mTc-Annexin V-128 uptake. Results 99mTc-HMPAO cerebral blood flow evaluation showed hypoperfusion during occlusion, partially restored on days 4 and 7 and sustained up to 14 days after middle cerebral artery occlusion. 99mTc-DTPA SPECT/CT showed a blood–brain barrier disruption starting on day 1 post-middle cerebral artery occlusion, peaking on day 2, with barrier integrity totally restored on day 7. 99mTc-Annexin V-128 SPECT/CT imaging showed significant positive correlation with TUNEL immunohistochemistry and allowed ischemic-induced apoptosis to be detected from day 2 to day 7, peaking on day 3 after middle cerebral artery occlusion. Conclusions Using SPECT/CT imaging, we showed that after transient middle cerebral artery occlusion in rat there was a sustained decrease in cerebral blood flow followed by blood–brain barrier disruption preceding meanwhile apoptosis. Rodent SPECT/CT imaging of cerebral blood flow, blood–brain barrier disruption and apoptosis appears to be an efficient tool for evaluating neuroprotective drugs and regenerative therapies against cerebral ischemia and time-windows for therapeutic intervention.
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Affiliation(s)
- Philippe Garrigue
- INSERM, INSERM UMR_S1076 VRCM Aix-Marseille Université, France
- APHM, Hôpital La Timone, Service de Radiopharmacie, Marseille, France
- CERIMED, Aix-Marseille Université, Marseille, France
| | - Laura Giacomino
- Département Anesthésie-Réanimation adulte, APHM, Aix-Marseille Université, Marseille, France
| | - Chiara Bucci
- Advanced Accelerator Applications, Colleretto Giacosa (TO), Italy
| | - Valeria Muzio
- Advanced Accelerator Applications, Colleretto Giacosa (TO), Italy
| | | | - Florence Sabatier
- INSERM, INSERM UMR_S1076 VRCM Aix-Marseille Université, France
- APHM, Laboratoire de Culture et Thérapie Cellulaire, INSERM, Hôpital La Conception, Marseille, France
| | - Françoise Dignat-George
- INSERM, INSERM UMR_S1076 VRCM Aix-Marseille Université, France
- APHM, Hôpital La Conception, Service d’Hématologie, Marseille, France
| | - Pascale Pisano
- INSERM, INSERM UMR_S1076 VRCM Aix-Marseille Université, France
- APHM, Pôle Pharmacie, Marseille, France
| | - Benjamin Guillet
- INSERM, INSERM UMR_S1076 VRCM Aix-Marseille Université, France
- APHM, Hôpital La Timone, Service de Radiopharmacie, Marseille, France
- CERIMED, Aix-Marseille Université, Marseille, France
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30
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Abstract
A multifunctional microRNA, miR-155, has been recently recognized as an important modulator of numerous biological processes. In our previous in vitro studies, miR-155 was identified as a potential regulator of the endothelial morphogenesis. The present study demonstrates that in vivo inhibition of miR-155 supports cerebral vasculature after experimental stroke. Intravenous injections of a specific miR-155 inhibitor were initiated at 48 h after mouse distal middle cerebral artery occlusion (dMCAO). Microvasculature in peri-infarct area, infarct size, and animal functional recovery were assessed at 1, 2, and 3 weeks after dMCAO. Using in vivo two-photon microscopy, we detected improved blood flow and microvascular integrity in the peri-infarct area of miR-155 inhibitor-injected mice. Electron microscopy revealed that, in contrast to the control group, these animals demonstrated well preserved capillary tight junctions (TJs). Western blot analysis data indicate that improved TJ integrity in the inhibitor-injected animals could be associated with stabilization of the TJ protein ZO-1 and mediated by the miR-155 target protein Rheb. MRI analysis showed significant (34%) reduction of infarct size in miR-155 inhibitor-injected animals at 21 d after dMCAO. Reduced brain injury was confirmed by electron microscopy demonstrating decreased neuronal damage in the peri-infarct area of stroke. Preservation of brain tissue was reflected in efficient functional recovery of inhibitor-injected animals. Based on our findings, we propose that in vivo miR-155 inhibition after ischemia supports brain microvasculature, reduces brain tissue damage, and improves the animal functional recovery. Significance statement: In the present study, we investigated an effect of the in vivo inhibition of a microRNA, miR-155, on brain recovery after experimental cerebral ischemia. To our knowledge, this is the first report describing the efficiency of intravenous anti-miRNA injections in a mouse model of ischemic stroke. The role of miRNAs in poststroke revascularization has been unexplored and in vivo regulation of miRNAs during the subacute phase of stroke has not yet been proposed. Our investigation introduces a new and unexplored approach to cerebral regeneration: regulation of poststroke angiogenesis and recovery through direct modulation of specific miRNA activity. We expect that our findings will lead to the development of novel strategies for regulating neurorestorative processes in the postischemic brain.
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31
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Zinnhardt B, Viel T, Wachsmuth L, Vrachimis A, Wagner S, Breyholz HJ, Faust A, Hermann S, Kopka K, Faber C, Dollé F, Pappata S, Planas AM, Tavitian B, Schäfers M, Sorokin LM, Kuhlmann MT, Jacobs AH. Multimodal imaging reveals temporal and spatial microglia and matrix metalloproteinase activity after experimental stroke. J Cereb Blood Flow Metab 2015; 35:1711-21. [PMID: 26126867 PMCID: PMC4635244 DOI: 10.1038/jcbfm.2015.149] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 05/11/2015] [Accepted: 05/15/2015] [Indexed: 12/12/2022]
Abstract
Stroke is the most common cause of death and disability from neurologic disease in humans. Activation of microglia and matrix metalloproteinases (MMPs) is involved in positively and negatively affecting stroke outcome. Novel, noninvasive, multimodal imaging methods visualizing microglial and MMP alterations were employed. The spatio-temporal dynamics of these parameters were studied in relation to blood flow changes. Micro positron emission tomography (μPET) using [(18)F]BR-351 showed MMP activity within the first days after transient middle cerebral artery occlusion (tMCAo), followed by increased [(18)F]DPA-714 uptake as a marker for microglia activation with a maximum at 14 days after tMCAo. The inflammatory response was spatially located in the infarct core and in adjacent (penumbral) tissue. For the first time, multimodal imaging based on PET, single photon emission computed tomography, and magnetic resonance imaging revealed insight into the spatio-temporal distribution of critical parameters of poststroke inflammation. This allows further evaluation of novel treatment paradigms targeting the postischemic inflammation.
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Affiliation(s)
- Bastian Zinnhardt
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms University Münster, Münster, Germany
| | - Thomas Viel
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms University Münster, Münster, Germany.,Paris Centre de Recherche Cardiovasculaire (PARC), Paris, France
| | - Lydia Wachsmuth
- Department of Clinical Radiology of the University Hospital, Westfälische Wilhelms University Münster, Münster, Germany
| | - Alexis Vrachimis
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms University Münster, Münster, Germany.,Department of Nuclear Medicine of the University Hospital, Westfälische Wilhelms University Münster, Münster, Germany
| | - Stefan Wagner
- Department of Nuclear Medicine of the University Hospital, Westfälische Wilhelms University Münster, Münster, Germany
| | - Hans-Jörg Breyholz
- Department of Nuclear Medicine of the University Hospital, Westfälische Wilhelms University Münster, Münster, Germany
| | - Andreas Faust
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms University Münster, Münster, Germany.,Department of Nuclear Medicine of the University Hospital, Westfälische Wilhelms University Münster, Münster, Germany.,Cells-in-Motion Cluster of Excellence (EXC 1003-CiM), Westfälische Wilhelms University Münster, Münster, Germany
| | - Sven Hermann
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms University Münster, Münster, Germany.,Department of Nuclear Medicine of the University Hospital, Westfälische Wilhelms University Münster, Münster, Germany.,Cells-in-Motion Cluster of Excellence (EXC 1003-CiM), Westfälische Wilhelms University Münster, Münster, Germany
| | - Klaus Kopka
- Department of Nuclear Medicine of the University Hospital, Westfälische Wilhelms University Münster, Münster, Germany.,Cells-in-Motion Cluster of Excellence (EXC 1003-CiM), Westfälische Wilhelms University Münster, Münster, Germany
| | - Cornelius Faber
- Department of Clinical Radiology of the University Hospital, Westfälische Wilhelms University Münster, Münster, Germany.,Cells-in-Motion Cluster of Excellence (EXC 1003-CiM), Westfälische Wilhelms University Münster, Münster, Germany
| | - Frédéric Dollé
- Service Hospitalier Frédéric Joliot, Institut d'Imagerie BioMédicale, CEA, Orsay, France
| | - Sabina Pappata
- Institute of Biostructure and Bioimaging, CNR, Naples, Italy
| | - Anna M Planas
- Institut d'Investigacions Biomèdiques de Barcelona, Consejo Superior de Investigaciones Científicas (CSIC), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | | | - Michael Schäfers
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms University Münster, Münster, Germany.,Department of Nuclear Medicine of the University Hospital, Westfälische Wilhelms University Münster, Münster, Germany.,Cells-in-Motion Cluster of Excellence (EXC 1003-CiM), Westfälische Wilhelms University Münster, Münster, Germany
| | - Lydia M Sorokin
- Cells-in-Motion Cluster of Excellence (EXC 1003-CiM), Westfälische Wilhelms University Münster, Münster, Germany.,Institute of Physiological Chemistry and Pathobiochemistry, Westfälische Wilhelms University Münster, Münster, Germany
| | - Michael T Kuhlmann
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms University Münster, Münster, Germany
| | - Andreas H Jacobs
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms University Münster, Münster, Germany.,Cells-in-Motion Cluster of Excellence (EXC 1003-CiM), Westfälische Wilhelms University Münster, Münster, Germany.,Department of Geriatrics, Johanniter Hospital, Evangelische Kliniken, Bonn, Germany
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32
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On the Role of the Blood Vessel Endothelial Microvilli in the Blood Flow in Small Capillaries. JOURNAL OF BIOPHYSICS 2015; 2015:529746. [PMID: 26604921 PMCID: PMC4641192 DOI: 10.1155/2015/529746] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 10/13/2015] [Indexed: 11/17/2022]
Abstract
Endothelial microvilli that protrude into the capillary lumen, although invisible in the optical microscopy, may play an important role in the blood flow control in the capillaries. Because of the plug effects, the width of the gap between the capillary wall and the blood cell is especially critical for the blood flow dynamics in capillaries, while microvilli located on the capillary wall can easily control the velocity of the blood flow. We report that microvilli in the capillaries of different vertebrate species have similar characteristics and density, suggesting similarities between the respective regulation mechanisms. A simplified physical model of the capillary effective diameter control by the microvilli is presented.
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Ikemoto K, Ishiyama T, Shintani N, Asano N, Sessler DI, Matsukawa T. The effects of topical and intravenous JM-1232(-) on cerebral pial microvessels of rabbits. BMC Anesthesiol 2015; 15:37. [PMID: 25805961 PMCID: PMC4372327 DOI: 10.1186/s12871-015-0016-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 02/24/2015] [Indexed: 11/30/2022] Open
Abstract
Background JM-1232(-) is a novel anesthetic agent which acts through gamma-aminobutyric acid receptors. Cerebral pial vascular effects of JM-1232(-) are unknown. We thus evaluated topical and intravenous effects of JM-1232(-) on cerebral pial microvessels in rabbits, and the extent to which carbon dioxide (CO2) reactivity is preserved. Methods Closed cranial windows were used to visualize cerebral pial circulation in 29 Japanese white rabbits. In the first experiment, the cranial window was superfused with increasing concentrations of JM-1232(-): 10-11, 10-9, 10-7, 10-5 mol/L, n = 8 per concentration. In the second experiment, we examined the effects of an intravenous bolus of 1 mg/kg bolus of JM-1232(-), followed by the continuous infusion at 0.3 mg/kg/minute on cerebral pial vascular alteration (n = 9). In the third, we examined CO2 reactivity of cerebral pial vessels under JM-1232(-) (n = 6) or sevoflurane anesthesia (n = 6). Results Topical application of JM-1232(-) did not change pial venular diameter, and constricted arterials only at the highest concentration. Intravenous administration of JM-1232(-) produced cerebral pial constriction which gradually diminished over time. Under intravenous administration of JM-1232(-) and inhaled sevoflurane, diameters of vessels increased in parallel with CO2 partial pressure. Slopes of linear regression and correlation coefficients in arterioles and venules were comparable for JM-1232(-) anesthesia and sevoflurane anesthesia. Conclusions Topical application of JM-1232(-) had little effect on cerebral pial vessels. Intravenous administration produced vasoconstriction of cerebral pial arterioles and venules, however those changes were clinically unimportant. In addition, JM-1232(-) did not impair CO2 responsiveness. At least from the perspective of vascular reactivity, JM-1232(-) thus appears safe for neurosurgical patients.
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Affiliation(s)
- Kodai Ikemoto
- Department of Anesthesiology, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo Yamanashi, 409-3898 Japan
| | - Tadahiko Ishiyama
- Surgical Center, University of Yamanashi Hospital, University of Yamanashi, 1110 Shimokato, Chuo Yamanashi, 409-3898 Japan
| | - Noriyuki Shintani
- Department of Anesthesiology, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo Yamanashi, 409-3898 Japan
| | - Nobumasa Asano
- Department of Anesthesiology, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo Yamanashi, 409-3898 Japan
| | - Daniel I Sessler
- Department of Outcomes Research, The Cleveland Clinic, Ohio, USA
| | - Takashi Matsukawa
- Department of Anesthesiology, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo Yamanashi, 409-3898 Japan
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34
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Shui S, Wang X, Chiang JY, Zheng L. Far-infrared therapy for cardiovascular, autoimmune, and other chronic health problems: A systematic review. Exp Biol Med (Maywood) 2015; 240:1257-65. [PMID: 25716016 DOI: 10.1177/1535370215573391] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2014] [Accepted: 12/31/2014] [Indexed: 01/08/2023] Open
Abstract
Physical therapy (physiotherapy), a complementary and alternative medicine therapy, has been widely applied in diagnosing and treating various diseases and defects. Increasing evidence suggests that convenient and non-invasive far-infrared (FIR) rays, a vital type of physiotherapy, improve the health of patients with cardiovascular disease, diabetes mellitus, and chronic kidney disease. Nevertheless, the molecular mechanisms by which FIR functions remain elusive. Hence, the purpose of this study was to review and summarize the results of previous investigations and to elaborate on the molecular mechanisms of FIR therapy in various types of disease. In conclusion, FIR therapy may be closely related to the increased expression of endothelial nitric oxide synthase as well as nitric oxide production and may modulate the profiles of some circulating miRNAs; thus, it may be a beneficial complement to treatments for some chronic diseases that yields no adverse effects.
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Affiliation(s)
- Shanshan Shui
- School of Medical Engineering, Hefei University of Technology, Hefei 230009, China School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China
| | - Xia Wang
- School of Medical Engineering, Hefei University of Technology, Hefei 230009, China
| | - John Y Chiang
- Department of Computer Science & Engineering, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan Department of Healthcare Administration and Medical Informatics, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Lei Zheng
- School of Medical Engineering, Hefei University of Technology, Hefei 230009, China School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China
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35
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Critical cerebral perfusion pressure at high intracranial pressure measured by induced cerebrovascular and intracranial pressure reactivity. Crit Care Med 2015; 42:2582-90. [PMID: 25289933 DOI: 10.1097/ccm.0000000000000655] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES The lower limit of cerebral blood flow autoregulation is the critical cerebral perfusion pressure at which cerebral blood flow begins to fall. It is important that cerebral perfusion pressure be maintained above this level to ensure adequate cerebral blood flow, especially in patients with high intracranial pressure. However, the critical cerebral perfusion pressure of 50 mm Hg, obtained by decreasing mean arterial pressure, differs from the value of 30 mm Hg, obtained by increasing intracranial pressure, which we previously showed was due to microvascular shunt flow maintenance of a falsely high cerebral blood flow. The present study shows that the critical cerebral perfusion pressure, measured by increasing intracranial pressure to decrease cerebral perfusion pressure, is inaccurate but accurately determined by dopamine-induced dynamic intracranial pressure reactivity and cerebrovascular reactivity. DESIGN Cerebral perfusion pressure was decreased either by increasing intracranial pressure or decreasing mean arterial pressure and the critical cerebral perfusion pressure by both methods compared. Cortical Doppler flux, intracranial pressure, and mean arterial pressure were monitored throughout the study. At each cerebral perfusion pressure, we measured microvascular RBC flow velocity, blood-brain barrier integrity (transcapillary dye extravasation), and tissue oxygenation (reduced nicotinamide adenine dinucleotide) in the cerebral cortex of rats using in vivo two-photon laser scanning microscopy. SETTING University laboratory. SUBJECTS Male Sprague-Dawley rats. INTERVENTIONS At each cerebral perfusion pressure, dopamine-induced arterial pressure transients (~10 mm Hg, ~45 s duration) were used to measure induced intracranial pressure reactivity (Δ intracranial pressure/Δ mean arterial pressure) and induced cerebrovascular reactivity (Δ cerebral blood flow/Δ mean arterial pressure). MEASUREMENTS AND MAIN RESULTS At a normal cerebral perfusion pressure of 70 mm Hg, 10 mm Hg mean arterial pressure pulses had no effect on intracranial pressure or cerebral blood flow (induced intracranial pressure reactivity = -0.03 ± 0.07 and induced cerebrovascular reactivity = -0.02 ± 0.09), reflecting intact autoregulation. Decreasing cerebral perfusion pressure to 50 mm Hg by increasing intracranial pressure increased induced intracranial pressure reactivity and induced cerebrovascular reactivity to 0.24 ± 0.09 and 0.31 ± 0.13, respectively, reflecting impaired autoregulation (p < 0.05). By static cerebral blood flow, the first significant decrease in cerebral blood flow occurred at a cerebral perfusion pressure of 30 mm Hg (0.71 ± 0.08, p < 0.05). CONCLUSIONS Critical cerebral perfusion pressure of 50 mm Hg was accurately determined by induced intracranial pressure reactivity and induced cerebrovascular reactivity, whereas the static method failed.
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36
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Bragin DE, Statom GL, Hagberg S, Nemoto EM. Increases in microvascular perfusion and tissue oxygenation via pulsed electromagnetic fields in the healthy rat brain. J Neurosurg 2014; 122:1239-47. [PMID: 25343187 DOI: 10.3171/2014.8.jns132083] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT High-frequency pulsed electromagnetic field stimulation is an emerging noninvasive therapy being used clinically to facilitate bone and cutaneous wound healing. Although the mechanisms of action of pulsed electromagnetic fields (PEMF) are unknown, some studies suggest that its effects are mediated by increased nitric oxide (NO), a well-known vasodilator. The authors hypothesized that in the brain, PEMF increase NO, which induces vasodilation, enhances microvascular perfusion and tissue oxygenation, and may be a useful adjunct therapy in stroke and traumatic brain injury. To test this hypothesis, they studied the effect of PEMF on a healthy rat brain with and without NO synthase (NOS) inhibition. METHODS In vivo two-photon laser scanning microscopy (2PLSM) was used on the parietal cortex of rat brains to measure microvascular tone and red blood cell (RBC) flow velocity in microvessels with diameters ranging from 3 to 50 μm, which includes capillaries, arterioles, and venules. Tissue oxygenation (reduced nicotinamide adenine dinucleotide [NADH] fluorescence) was also measured before and for 3 hours after PEMF treatment using the FDA-cleared SofPulse device (Ivivi Health Sciences, LLC). To test NO involvement, the NOS inhibitor N(G)-nitro-l-arginine methyl ester (L-NAME) was intravenously injected (10 mg/kg). In a time control group, PEMF were not used. Doppler flux (0.8-mm probe diameter), brain and rectal temperatures, arterial blood pressure, blood gases, hematocrit, and electrolytes were monitored. RESULTS Pulsed electromagnetic field stimulation significantly dilated cerebral arterioles from a baseline average diameter of 26.4 ± 0.84 μm to 29.1 ± 0.91 μm (11 rats, p < 0.01). Increased blood volume flow through dilated arterioles enhanced capillary flow with an average increase in RBC flow velocity by 5.5% ± 1.3% (p < 0.01). Enhanced microvascular flow increased tissue oxygenation as reflected by a decrease in NADH autofluorescence to 94.7% ± 1.6% of baseline (p < 0.05). Nitric oxide synthase inhibition by L-NAME prevented PEMF-induced changes in arteriolar diameter, microvascular perfusion, and tissue oxygenation (7 rats). No changes in measured parameters were observed throughout the study in the untreated time controls (5 rats). CONCLUSIONS This is the first demonstration of the acute effects of PEMF on cerebral cortical microvascular perfusion and metabolism. Thirty minutes of PEMF treatment induced cerebral arteriolar dilation leading to an increase in microvascular blood flow and tissue oxygenation that persisted for at least 3 hours. The effects of PEMF were mediated by NO, as we have shown in NOS inhibition experiments. These results suggest that PEMF may be an effective treatment for patients after traumatic or ischemic brain injury. Studies on the effect of PEMF on the injured brain are in progress.
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37
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Effects of levosimendan on hemodynamics, local cerebral blood flow, neuronal injury, and neuroinflammation after asphyctic cardiac arrest in rats. Crit Care Med 2014; 42:e410-9. [PMID: 24633188 DOI: 10.1097/ccm.0000000000000308] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVES Despite advances in cardiac arrest treatment, high mortality and morbidity rates after successful cardiopulmonary resuscitation are still a major clinical relevant problem. The post cardiac arrest syndrome subsumes myocardial dysfunction, impaired microcirculation, systemic inflammatory response, and neurological impairment. The calcium-sensitizer levosimendan was able to improve myocardial function and initial resuscitation success after experimental cardiac arrest/cardiopulmonary resuscitation. We hypothesized that levosimendan exerts beneficial effects on cerebral blood flow, neuronal injury, neurological outcome, and inflammation 24 hours after experimental cardiac arrest/cardiopulmonary resuscitation. DESIGN Laboratory animal study. SETTING University animal research laboratory. SUBJECTS Sixty-one male Sprague-Dawley rats. INTERVENTIONS Animals underwent asphyxial cardiac arrest/cardiopulmonary resuscitation, randomized to groups with levosimendan treatment (bolus 12 µg/kg and infusion for 3 hr [0.3 µg/min/kg]) or vehicle (saline 0.9% bolus and infusion for 3 hr [equivalent fluid volume]). Cardiac index, local cerebral blood flow, and hemodynamic variables were measured for 180 minutes after cardiac arrest/cardiopulmonary resuscitation. Behavioral and neurological evaluations were conducted 24 hours after cardiac arrest/cardiopulmonary resuscitation. Furthermore, neuronal injury, expressed as Fluoro-Jade B-positive cells in the hippocampal formation, cortical and hippocampal inflammatory cytokine gene expression, and blood plasma interleukin-6 values were assessed. MEASUREMENTS AND MAIN RESULTS Treatment with levosimendan reduced neuronal injury and improved neurological outcome after 24 hours of reperfusion and resulted in elevated cardiac index and local cerebral blood flow compared with vehicle after cardiac arrest/cardiopulmonary resuscitation. Mean arterial blood pressure was reduced during the early reperfusion period in the levosimendan group. Cortical and hippocampal inflammatory cytokine gene expression and blood plasma interleukin-6 levels were not influenced. CONCLUSIONS Levosimendan increased cerebral blood flow after experimental cardiac arrest/cardiopulmonary resuscitation. This effect coincided with reduced neuronal injury and improved neurologic outcome. Findings seem to be independent of inflammatory effects because no effects by levosimendan on cerebral or systemic inflammation could be detected. In summary, levosimendan is a promising agent to improve neurological outcome after cardiac arrest/cardiopulmonary resuscitation.
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38
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39
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Hall CN, Reynell C, Gesslein B, Hamilton NB, Mishra A, Sutherland BA, O'Farrell FM, Buchan AM, Lauritzen M, Attwell D. Capillary pericytes regulate cerebral blood flow in health and disease. Nature 2014; 508:55-60. [PMID: 24670647 PMCID: PMC3976267 DOI: 10.1038/nature13165] [Citation(s) in RCA: 1269] [Impact Index Per Article: 126.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 02/19/2014] [Indexed: 01/12/2023]
Abstract
Increases in brain blood flow, evoked by neuronal activity, power neural computation and form the basis of BOLD (blood-oxygen-level-dependent) functional imaging. Whether blood flow is controlled solely by arteriole smooth muscle, or also by capillary pericytes, is controversial. We demonstrate that neuronal activity and the neurotransmitter glutamate evoke the release of messengers that dilate capillaries by actively relaxing pericytes. Dilation is mediated by prostaglandin E2, but requires nitric oxide release to suppress vasoconstricting 20-HETE synthesis. In vivo, when sensory input increases blood flow, capillaries dilate before arterioles and are estimated to produce 84% of the blood flow increase. In pathology, ischaemia evokes capillary constriction by pericytes. We show that this is followed by pericyte death in rigor, which may irreversibly constrict capillaries and damage the blood-brain barrier. Thus, pericytes are major regulators of cerebral blood flow and initiators of functional imaging signals. Prevention of pericyte constriction and death may reduce the long-lasting blood flow decrease that damages neurons after stroke.
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Affiliation(s)
- Catherine N Hall
- Department of Neuroscience, Physiology & Pharmacology University College London, Gower St., London, WC1E 6BT, UK
| | - Clare Reynell
- Department of Neuroscience, Physiology & Pharmacology University College London, Gower St., London, WC1E 6BT, UK
| | - Bodil Gesslein
- Department of Neuroscience & Pharmacology and Center for Healthy Aging, and Department of Clinical Neurophysiology, Glostrup Hospital, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Nicola B Hamilton
- Department of Neuroscience, Physiology & Pharmacology University College London, Gower St., London, WC1E 6BT, UK
| | - Anusha Mishra
- Department of Neuroscience, Physiology & Pharmacology University College London, Gower St., London, WC1E 6BT, UK
| | - Brad A Sutherland
- Acute Stroke Programme, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK
| | - Fergus M O'Farrell
- Department of Neuroscience, Physiology & Pharmacology University College London, Gower St., London, WC1E 6BT, UK
| | - Alastair M Buchan
- Acute Stroke Programme, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK
| | - Martin Lauritzen
- Department of Neuroscience & Pharmacology and Center for Healthy Aging, and Department of Clinical Neurophysiology, Glostrup Hospital, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - David Attwell
- Department of Neuroscience, Physiology & Pharmacology University College London, Gower St., London, WC1E 6BT, UK
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40
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Li M, Then WL, Li L, Shen W. Paper-based device for rapid typing of secondary human blood groups. Anal Bioanal Chem 2013; 406:669-77. [DOI: 10.1007/s00216-013-7494-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 11/04/2013] [Accepted: 11/06/2013] [Indexed: 12/11/2022]
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41
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Weiss HR, Grayson J, Liu X, Barsoum S, Shah H, Chi OZ. Cerebral Ischemia and Reperfusion Increases the Heterogeneity of Local Oxygen Supply/Consumption Balance. Stroke 2013; 44:2553-8. [DOI: 10.1161/strokeaha.113.001172] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Background and Purpose—
After cerebral vessel blockage, local blood flow and O
2
consumption becomes lower and oxygen extraction increases. With reperfusion, blood flow is partially restored. We examined the effects of ischemia-reperfusion on the heterogeneity of local venous oxygen saturation in rats in order to determine the pattern of microregional O
2
supply/consumption balance in reperfusion.
Methods—
The middle cerebral artery was blocked for 1 hour using the internal carotid approach in 1 group (n=9) and was then reperfused for 2 hours in another group (n=9) of isoflurane-anesthetized rats. Regional cerebral blood flow was determined using a C
14
-iodoantipyrine autoradiographic technique. Regional small vessel arterial and venous oxygen saturations were determined microspectrophotometrically.
Results—
After 1 hour of ischemia, local cerebral blood flow (92±10 versus 50±10 mL/min per 100 g) and O
2
consumption (4.5±0.6 versus 2.7±0.5 mL O
2
/min per 100 g) decreased compared with the contralateral cortex. Oxygen extraction increased (4.7±0.2 versus 5.4±0.3 mL O
2
/100 mL) and the variation in small vein (20–60 μm) O
2
saturation as determined by its coefficient of variation (=100×SD/mean) increased (5.5 versus 10.5). With 2 hours of reperfusion, the blood flow decrement was reduced and O
2
consumption returned to the value in the contralateral cortex. Oxygen extraction remained elevated in the ischemic-reperfused area and the coefficient of variation of small vein O
2
saturation increased further (17.3).
Conclusions—
These data indicated continued reduction of O
2
supply/consumption balance with reperfusion. They also demonstrated many small regions of low oxygenation within the reperfused cortical region.
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Affiliation(s)
- Harvey R. Weiss
- From the Department of Neuroscience and Cell Biology (H.R.W., H.S.) and Department of Anesthesiology (J.G., X.L., S.B., O.Z.C.), Rutgers Robert Wood Johnson Medical School, Piscataway, NJ
| | - Jeremy Grayson
- From the Department of Neuroscience and Cell Biology (H.R.W., H.S.) and Department of Anesthesiology (J.G., X.L., S.B., O.Z.C.), Rutgers Robert Wood Johnson Medical School, Piscataway, NJ
| | - Xia Liu
- From the Department of Neuroscience and Cell Biology (H.R.W., H.S.) and Department of Anesthesiology (J.G., X.L., S.B., O.Z.C.), Rutgers Robert Wood Johnson Medical School, Piscataway, NJ
| | - Sylviana Barsoum
- From the Department of Neuroscience and Cell Biology (H.R.W., H.S.) and Department of Anesthesiology (J.G., X.L., S.B., O.Z.C.), Rutgers Robert Wood Johnson Medical School, Piscataway, NJ
| | - Harsh Shah
- From the Department of Neuroscience and Cell Biology (H.R.W., H.S.) and Department of Anesthesiology (J.G., X.L., S.B., O.Z.C.), Rutgers Robert Wood Johnson Medical School, Piscataway, NJ
| | - Oak Z. Chi
- From the Department of Neuroscience and Cell Biology (H.R.W., H.S.) and Department of Anesthesiology (J.G., X.L., S.B., O.Z.C.), Rutgers Robert Wood Johnson Medical School, Piscataway, NJ
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Wong AD, Ye M, Levy AF, Rothstein JD, Bergles DE, Searson PC. The blood-brain barrier: an engineering perspective. FRONTIERS IN NEUROENGINEERING 2013; 6:7. [PMID: 24009582 PMCID: PMC3757302 DOI: 10.3389/fneng.2013.00007] [Citation(s) in RCA: 380] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 08/07/2013] [Indexed: 12/03/2022]
Abstract
It has been more than 100 years since Paul Ehrlich reported that various water-soluble dyes injected into the circulation did not enter the brain. Since Ehrlich's first experiments, only a small number of molecules, such as alcohol and caffeine have been found to cross the blood-brain barrier, and this selective permeability remains the major roadblock to treatment of many central nervous system diseases. At the same time, many central nervous system diseases are associated with disruption of the blood-brain barrier that can lead to changes in permeability, modulation of immune cell transport, and trafficking of pathogens into the brain. Therefore, advances in our understanding of the structure and function of the blood-brain barrier are key to developing effective treatments for a wide range of central nervous system diseases. Over the past 10 years it has become recognized that the blood-brain barrier is a complex, dynamic system that involves biomechanical and biochemical signaling between the vascular system and the brain. Here we reconstruct the structure, function, and transport properties of the blood-brain barrier from an engineering perspective. New insight into the physics of the blood-brain barrier could ultimately lead to clinical advances in the treatment of central nervous system diseases.
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Affiliation(s)
- Andrew D. Wong
- Department of Materials Science and Engineering, Johns Hopkins UniversityBaltimore, MD, USA
- Institute for Nanobiotechnology, Johns Hopkins UniversityBaltimore, MD, USA
| | - Mao Ye
- Department of Materials Science and Engineering, Johns Hopkins UniversityBaltimore, MD, USA
- Institute for Nanobiotechnology, Johns Hopkins UniversityBaltimore, MD, USA
| | - Amanda F. Levy
- Department of Materials Science and Engineering, Johns Hopkins UniversityBaltimore, MD, USA
- Institute for Nanobiotechnology, Johns Hopkins UniversityBaltimore, MD, USA
| | - Jeffrey D. Rothstein
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins UniversityBaltimore, MD, USA
- Brain Sciences Institute, Johns Hopkins UniversityBaltimore, MD, USA
| | - Dwight E. Bergles
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins UniversityBaltimore, MD, USA
| | - Peter C. Searson
- Department of Materials Science and Engineering, Johns Hopkins UniversityBaltimore, MD, USA
- Institute for Nanobiotechnology, Johns Hopkins UniversityBaltimore, MD, USA
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Acute microvascular changes after subarachnoid hemorrhage and transient global cerebral ischemia. Stroke Res Treat 2013; 2013:425281. [PMID: 23589781 PMCID: PMC3621372 DOI: 10.1155/2013/425281] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 02/26/2013] [Accepted: 02/28/2013] [Indexed: 01/27/2023] Open
Abstract
Subarachnoid hemorrhage and transient global cerebral ischemia result in similar pathophysiological changes in the cerebral microcirculation. These changes include microvascular constriction, increased leukocyte-endothelial interactions, blood brain barrier disruption, and microthrombus formation. This paper will look at various animal and preclinical studies that investigate these various microvascular changes, perhaps providing insight in how these microvessels can be a therapeutic target in both subarachnoid hemorrhage and transient global cerebral ischemia.
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Li L, Tian J, Ballerini D, Li M, Shen W. A study of the transport and immobilisation mechanisms of human red blood cells in a paper-based blood typing device using confocal microscopy. Analyst 2013; 138:4933-40. [DOI: 10.1039/c3an00810j] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Bragin DE, Bush RC, Nemoto EM. Effect of cerebral perfusion pressure on cerebral cortical microvascular shunting at high intracranial pressure in rats. Stroke 2012. [PMID: 23204051 DOI: 10.1161/strokeaha.112.668293] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Recently, we showed that decreasing cerebral perfusion pressure (CPP) from 70 mm Hg to 50 mm Hg and 30 mm Hg by increasing intracranial pressure (ICP) with a fluid reservoir induces a transition from capillary (CAP) to microvascular shunt (MVS) flow in the uninjured rat brain. This transition was associated with tissue hypoxia, increased blood-brain barrier (BBB) permeability, and brain edema. Our aim was to determine whether an increase in CPP would attenuate the transition to MVS flow at high ICP. METHODS Rats were subjected to progressive, step-wise increases in ICP of up to 60 mm Hg by an artificial cerebrospinal fluid reservoir connected to the cisterna magna. CPP was maintained at 50, 60, 70, or 80 mm Hg by intravenous dopamine infusion. Microvascular red blood cell flow velocity, BBB integrity (fluorescein dye extravasation), and tissue oxygenation (nicotinamide adenine dinucleotide) were measured by in vivo 2-photon laser scanning microscopy. Doppler cortical flux, rectal and cranial temperatures, ICP, arterial blood pressure, and gases were monitored. RESULTS The CAP/MVS ratio increased (P<0.05) at higher ICP as CPP was increased from 50 to 80 mm Hg. At an ICP of 30 mm Hg and CPP of 50 mm Hg, the CAP/MVS ratio was 0.6±0.1. At CPP of 60, 70, and 80 mm Hg, the ratio increased to 0.9±0.1, 1.4±0.1, and 1.9±0.1, respectively (mean±SEM; P<0.05). BBB opening and increase of reduced form of nicotinamide adenine dinucleotide occurred at higher ICP as CPP was increased. CONCLUSIONS Increasing CPP at high ICP attenuates the transition from CAP to MVS flow, development of tissue hypoxia, and increased BBB permeability.
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Affiliation(s)
- Denis E Bragin
- Department of Neurosurgery, University of New Mexico School of Medicine, 1 University of New Mexico MSC10-5615, Albuquerque, NM 87131, USA.
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Abstract
Cerebral blood volume (CBV) changes significantly with brain activation, whether measured using positron emission tomography, functional magnetic resonance imaging (fMRI), or optical microscopy. If cerebral vessels are considered to be impermeable, the contents of the skull incompressible, and the skull itself inextensible, task- and hypercapnia-related changes of CBV could produce intolerable changes of intracranial pressure. Because it is becoming clear that CBV may be useful as a well-localized marker of neural activity changes, a resolution of this apparent paradox is needed. We have explored the idea that much of the change in CBV is facilitated by exchange of water between capillaries and surrounding tissue. To this end, we developed a novel hemodynamic boundary-value model and found approximate solutions using a numerical algorithm. We also constructed a macroscopic experimental model of a single capillary to provide biophysical insight. Both experiment and theory model capillary membranes as elastic and permeable. For a realistic change of input pressure, a relative pipe volume change of 21±5% was observed when using the experimental setup, compared with the value of approximately 17±1% when this quantity was calculated from the mathematical model. Volume, axial flow, and pressure changes are in the expected range.
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Effects of a single-dose hypertonic saline hydroxyethyl starch on cerebral blood flow, long-term outcome, neurogenesis, and neuronal survival after cardiac arrest and cardiopulmonary resuscitation in rats*. Crit Care Med 2012; 40:2149-56. [DOI: 10.1097/ccm.0b013e31824e6750] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Frydrychowski AF, Wszedybyl-Winklewska M, Guminski W, Lass P, Bandurski T, Winklewski PJ. Effects of acute hypercapnia on the amplitude of cerebrovascular pulsation in humans registered with a non-invasive method. Microvasc Res 2012; 83:229-36. [DOI: 10.1016/j.mvr.2011.08.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 03/07/2011] [Accepted: 08/13/2011] [Indexed: 11/15/2022]
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Karbowski J. Scaling of brain metabolism and blood flow in relation to capillary and neural scaling. PLoS One 2011; 6:e26709. [PMID: 22053202 PMCID: PMC3203885 DOI: 10.1371/journal.pone.0026709] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Accepted: 10/02/2011] [Indexed: 11/18/2022] Open
Abstract
Brain is one of the most energy demanding organs in mammals, and its total metabolic rate scales with brain volume raised to a power of around 5/6. This value is significantly higher than the more common exponent 3/4 relating whole body resting metabolism with body mass and several other physiological variables in animals and plants. This article investigates the reasons for brain allometric distinction on a level of its microvessels. Based on collected empirical data it is found that regional cerebral blood flow CBF across gray matter scales with cortical volume as , brain capillary diameter increases as , and density of capillary length decreases as . It is predicted that velocity of capillary blood is almost invariant (), capillary transit time scales as , capillary length increases as , and capillary number as , where is typically a small correction for medium and large brains, due to blood viscosity dependence on capillary radius. It is shown that the amount of capillary length and blood flow per cortical neuron are essentially conserved across mammals. These results indicate that geometry and dynamics of global neuro-vascular coupling have a proportionate character. Moreover, cerebral metabolic, hemodynamic, and microvascular variables scale with allometric exponents that are simple multiples of 1/6, rather than 1/4, which suggests that brain metabolism is more similar to the metabolism of aerobic than resting body. Relation of these findings to brain functional imaging studies involving the link between cerebral metabolism and blood flow is also discussed.
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Affiliation(s)
- Jan Karbowski
- Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw, Poland.
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Sutherland BA, Papadakis M, Chen RL, Buchan AM. Cerebral blood flow alteration in neuroprotection following cerebral ischaemia. J Physiol 2011; 589:4105-14. [PMID: 21708904 DOI: 10.1113/jphysiol.2011.209601] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The best neuroprotectant for acute ischaemic stroke would always be the rapid return of oxygen and glucose to physiological levels. This is currently provided by thrombolysis which restores blood flow to the ischaemic region. The attempt to confer neuroprotection by targeting the brain parenchyma has shown promise in experimental stroke models, but has unequivocally failed to translate to the clinic. Neuroprotective therapy primarily targets the biochemical cascade that produces cell death following cerebral ischaemia. However, these agents may also alter signal transduction that controls cerebral blood flow, for example glutamate, which may affect the outcome after ischaemia. In these cases, neuroprotection may potentially be due to the improved access to oxygen and glucose rather than biochemical prevention of cell death. Improvement in cerebral blood flow is an important but often overlooked effect of neuroprotective therapy, analogous to the protective effects of drug-induced hypothermia. This short review will discuss cerebral blood flow alteration and protection of the brain in the context of ischaemic preconditioning, oxygen sensing and thrombolysis. Future neuroprotection studies in cerebral ischaemia require stringent monitoring of cerebral blood flow, plus other physiological parameters. This will increase the chances that any protection observed may be able to translate to human therapy.
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Affiliation(s)
- Brad A Sutherland
- Acute Stroke Programme, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
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