101
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Sciortino VM, Tran A, Sun N, Cao R, Sun T, Sun YY, Yan P, Zhong F, Zhou Y, Kuan CY, Lee JM, Hu S. Longitudinal cortex-wide monitoring of cerebral hemodynamics and oxygen metabolism in awake mice using multi-parametric photoacoustic microscopy. J Cereb Blood Flow Metab 2021; 41:3187-3199. [PMID: 34304622 PMCID: PMC8669277 DOI: 10.1177/0271678x211034096] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Multi-parametric photoacoustic microscopy (PAM) has emerged as a promising new technique for high-resolution quantification of hemodynamics and oxygen metabolism in the mouse brain. In this work, we have extended the scope of multi-parametric PAM to longitudinal, cortex-wide, awake-brain imaging with the use of a long-lifetime (24 weeks), wide-field (5 × 7 mm2), light-weight (2 g), dual-transparency (i.e., light and ultrasound) cranial window. Cerebrovascular responses to the window installation were examined in vivo, showing a complete recovery in 18 days. In the 22-week monitoring after the recovery, no dura thickening, skull regrowth, or changes in cerebrovascular structure and function were observed. The promise of this technique was demonstrated by monitoring vascular and metabolic responses of the awake mouse brain to ischemic stroke throughout the acute, subacute, and chronic stages. Side-by-side comparison of the responses in the ipsilateral (injury) and contralateral (control) cortices shows that despite an early recovery of cerebral blood flow and an increase in microvessel density, a long-lasting deficit in cerebral oxygen metabolism was observed throughout the chronic stage in the injured cortex, part of which proceeded to infarction. This longitudinal, functional-metabolic imaging technique opens new opportunities to study the chronic progression and therapeutic responses of neurovascular diseases.
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Affiliation(s)
- Vincent M Sciortino
- Department of Biomedical Engineering, 2358University of Virginia, University of Virginia, Charlottesville, VA, USA
| | - Angela Tran
- Department of Biology, 2358University of Virginia, University of Virginia, Charlottesville, VA, USA
| | - Naidi Sun
- Department of Biomedical Engineering, 2358University of Virginia, University of Virginia, Charlottesville, VA, USA.,Department of Neurology, Washington University in St. Louis, St. Louis, MO, USA
| | - Rui Cao
- Department of Biomedical Engineering, 2358University of Virginia, University of Virginia, Charlottesville, VA, USA
| | - Tao Sun
- Department of Biomedical Engineering, 2358University of Virginia, University of Virginia, Charlottesville, VA, USA.,Department of Neurology, Washington University in St. Louis, St. Louis, MO, USA
| | - Yu-Yo Sun
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Ping Yan
- Department of Neuroscience, 2358University of Virginia, University of Virginia, Charlottesville, VA, USA
| | - Fenghe Zhong
- Department of Biomedical Engineering, 2358University of Virginia, University of Virginia, Charlottesville, VA, USA.,Department of Neurology, Washington University in St. Louis, St. Louis, MO, USA
| | - Yifeng Zhou
- Department of Biomedical Engineering, 2358University of Virginia, University of Virginia, Charlottesville, VA, USA.,Department of Neurology, Washington University in St. Louis, St. Louis, MO, USA
| | - Chia-Yi Kuan
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Jin-Moo Lee
- Department of Neuroscience, 2358University of Virginia, University of Virginia, Charlottesville, VA, USA.,Department of Neurology, Washington University in St. Louis, St. Louis, MO, USA
| | - Song Hu
- Department of Biomedical Engineering, 2358University of Virginia, University of Virginia, Charlottesville, VA, USA.,Department of Neurology, Washington University in St. Louis, St. Louis, MO, USA
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102
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Wei H, Frey AM, Jasanoff A. Molecular fMRI of neurochemical signaling. J Neurosci Methods 2021; 364:109372. [PMID: 34597714 DOI: 10.1016/j.jneumeth.2021.109372] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/23/2021] [Accepted: 09/25/2021] [Indexed: 12/12/2022]
Abstract
Magnetic resonance imaging (MRI) is the most widely applied technique for brain-wide measurement of neural function in humans and animals. In conventional functional MRI (fMRI), brain signaling is detected indirectly, via localized activity-dependent changes in regional blood flow, oxygenation, and volume, to which MRI contrast can be readily sensitized. Although such hemodynamic fMRI methods are powerful tools for analysis of brain activity, they lack specificity for the many molecules and cell types that play functionally distinct roles in neural processing. A suite of techniques collectively known to as "molecular fMRI," addresses this limitation by permitting MRI-based detection of specific molecular processes in deep brain tissue. This review discusses how molecular fMRI is coming to be used in the study of neurochemical dynamics that mediate intercellular communication in the brain. Neurochemical molecular fMRI is a potentially powerful approach for mechanistic analysis of brain-wide function, but the techniques are still in early stages of development. Here we provide an overview of the major advances and results that have been achieved to date, as well as directions for further development.
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Affiliation(s)
- He Wei
- Department of Biological Engineering, Massachusetts Institute of Technology, United States
| | - Abigail M Frey
- Department of Chemical Engineering, Massachusetts Institute of Technology, United States
| | - Alan Jasanoff
- Department of Biological Engineering, Massachusetts Institute of Technology, United States; Department of Brain & Cognitive Sciences, Massachusetts Institute of Technology, United States; Department of Nuclear Science & Engineering, Massachusetts Institute of Technology, United States.
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103
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Chen C, She Z, Tang P, Qin Z, He J, Qu JY. Study of neurovascular coupling by using mesoscopic and microscopic imaging. iScience 2021; 24:103176. [PMID: 34693226 PMCID: PMC8511898 DOI: 10.1016/j.isci.2021.103176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 07/02/2021] [Accepted: 09/22/2021] [Indexed: 12/05/2022] Open
Abstract
Neuronal activation is often accompanied by the regulation of cerebral hemodynamics via a process known as neurovascular coupling (NVC) which is essential for proper brain function and has been observed to be disrupted in a variety of neuropathologies. A comprehensive understanding of NVC requires imaging capabilities with high spatiotemporal resolution and a field-of-view that spans different orders of magnitude. Here, we present an approach for concurrent multi-contrast mesoscopic and two-photon microscopic imaging of neurovascular dynamics in the cortices of live mice. We investigated the spatiotemporal correlation between sensory-evoked neuronal and vascular responses in the auditory cortices of living mice using four imaging modalities. Our findings unravel drastic differences in the NVC at the regional and microvascular levels and the distinctive effects of different brain states on NVC. We further investigated the brain-state-dependent changes of NVC in large cortical networks and revealed that anesthesia and sedation caused spatiotemporal disruption of NVC. Concurrent mesoscopic and microscopic imaging of neurovascular dynamics Spatiotemporal characteristics of neurovascular responses across multiple scales Distinct effects of anesthesia and sedation on neurovascular coupling Cortex-wide correlation of neuronal activity and cerebral hemodynamics
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Affiliation(s)
- Congping Chen
- Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China.,State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China.,Center of Systems Biology and Human Health, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China
| | - Zhentao She
- Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China.,State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China.,Center of Systems Biology and Human Health, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China
| | - Peng Tang
- Department of Neuroscience (NS), City University of Hong Kong, Hong Kong, P.R. China.,Centre for Regenerative Medicine and Health, Hong Kong Institute of Science & Innovation, Chinese Academy of Sciences, Hong Kong SAR, P.R. China
| | - Zhongya Qin
- Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China.,State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China.,Center of Systems Biology and Human Health, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China
| | - Jufang He
- Department of Neuroscience (NS), City University of Hong Kong, Hong Kong, P.R. China
| | - Jianan Y Qu
- Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China.,State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China.,Center of Systems Biology and Human Health, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China
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104
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Shapira R, Gdalyahu A, Gottfried I, Sasson E, Hadanny A, Efrati S, Blinder P, Ashery U. Hyperbaric oxygen therapy alleviates vascular dysfunction and amyloid burden in an Alzheimer's disease mouse model and in elderly patients. Aging (Albany NY) 2021; 13:20935-20961. [PMID: 34499614 PMCID: PMC8457592 DOI: 10.18632/aging.203485] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 08/10/2021] [Indexed: 04/21/2023]
Abstract
Vascular dysfunction is entwined with aging and in the pathogenesis of Alzheimer's disease (AD) and contributes to reduced cerebral blood flow (CBF) and consequently, hypoxia. Hyperbaric oxygen therapy (HBOT) is in clinical use for a wide range of medical conditions. In the current study, we exposed 5XFAD mice, a well-studied AD model that presents impaired cognitive abilities, to HBOT and then investigated the therapeutical effects using two-photon live animal imaging, behavioral tasks, and biochemical and histological analysis. HBOT increased arteriolar luminal diameter and elevated CBF, thus contributing to reduced hypoxia. Furthermore, HBOT reduced amyloid burden by reducing the volume of pre-existing plaques and attenuating the formation of new ones. This was associated with changes in amyloid precursor protein processing, elevated degradation and clearance of Aß protein and improved behavior of 5XFAD mice. Hence, our findings are consistent with the effects of HBOT being mediated partially through a persistent structural change in blood vessels that reduces brain hypoxia. Motivated by these findings, we exposed elderly patients with significant memory loss at baseline to HBOT and observed an increase in CBF and improvement in cognitive performances. This study demonstrates HBOT efficacy in hypoxia-related neurological conditions, particularly in AD and aging.
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Affiliation(s)
- Ronit Shapira
- School of Neurobiology, Biochemistry and Biophysics, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel-Aviv, Israel
| | - Amos Gdalyahu
- School of Neurobiology, Biochemistry and Biophysics, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel-Aviv, Israel
| | - Irit Gottfried
- School of Neurobiology, Biochemistry and Biophysics, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel-Aviv, Israel
| | - Efrat Sasson
- Sagol Center for Hyperbaric Medicine and Research, Assaf Harofeh Medical Center, Be’er Ya’akov, Israel
| | - Amir Hadanny
- Sagol Center for Hyperbaric Medicine and Research, Assaf Harofeh Medical Center, Be’er Ya’akov, Israel
| | - Shai Efrati
- Sagol School of Neuroscience, Tel Aviv University, Tel-Aviv, Israel
- Sackler School of Medicine, Tel Aviv University, Tel-Aviv, Israel
- Sagol Center for Hyperbaric Medicine and Research, Assaf Harofeh Medical Center, Be’er Ya’akov, Israel
| | - Pablo Blinder
- School of Neurobiology, Biochemistry and Biophysics, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel-Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, Tel-Aviv, Israel
| | - Uri Ashery
- School of Neurobiology, Biochemistry and Biophysics, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel-Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, Tel-Aviv, Israel
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105
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Liu K, Zhu J, Chang Y, Lin Z, Shi Z, Li X, Chen X, Lin C, Pan S, Huang K. Attenuation of cerebral edema facilitates recovery of glymphatic system function after status epilepticus. JCI Insight 2021; 6:e151835. [PMID: 34494549 PMCID: PMC8492308 DOI: 10.1172/jci.insight.151835] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 07/15/2021] [Indexed: 11/17/2022] Open
Abstract
Status epilepticus (SE) is a neurological emergency usually accompanied by acute cerebral edema and long-term cognitive impairment, and is characterized by neurodegeneration and aberrant hyperphosphorylated tau protein (p-tau) aggregation. The glia-lymphatic (glymphatic) system plays a central role in facilitating the clearance of metabolic waste from the brain, but its relationship with cerebral edema and cognitive dysfunction after SE is unclear. We hypothesized that cerebral edema after SE might impair glymphatic system function through compression, thus leading to impaired removal of metabolic waste, and ultimately affecting long-term cognitive function. Our results showed that glymphatic system function was temporarily impaired, as evidenced by 2-photon imaging, MRI enhancement, imaging of brain sections, and astrocytic water channel aquaporin 4 (AQP4) protein polarization. The severity of cerebral edema on MRI correlated well with glymphatic system dysfunction within 8 days following SE. Moreover, when cerebral edema was alleviated by glibenclamide treatment or genetic deletion of Trpm4, post-SE glymphatic system function recovered earlier, along with fewer p-tau–deposited neurons and neuronal degeneration and better cognitive function. These findings suggest that SE-induced cerebral edema may cause glymphatic system dysfunction and render the post-SE brain vulnerable to p-tau aggregation and neurocognitive impairment.
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Affiliation(s)
- Kewei Liu
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Juan Zhu
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yuan Chang
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Zhenzhou Lin
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Zhu Shi
- Department of Neurology, Dongguan Hospital, Southern Medical University, Dongguan, China
| | - Xing Li
- Department of Neurology, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, Guangdong, China
| | - Xing Chen
- Department of Neurology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Chuman Lin
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Suyue Pan
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Kaibin Huang
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou, China
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106
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Chen X, Jiang Y, Choi S, Pohmann R, Scheffler K, Kleinfeld D, Yu X. Assessment of single-vessel cerebral blood velocity by phase contrast fMRI. PLoS Biol 2021; 19:e3000923. [PMID: 34499636 PMCID: PMC8454982 DOI: 10.1371/journal.pbio.3000923] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 09/21/2021] [Accepted: 07/28/2021] [Indexed: 12/30/2022] Open
Abstract
Current approaches to high-field functional MRI (fMRI) provide 2 means to map hemodynamics at the level of single vessels in the brain. One is through changes in deoxyhemoglobin in venules, i.e., blood oxygenation level-dependent (BOLD) fMRI, while the second is through changes in arteriole diameter, i.e., cerebral blood volume (CBV) fMRI. Here, we introduce cerebral blood flow-related velocity-based fMRI, denoted CBFv-fMRI, which uses high-resolution phase contrast (PC) MRI to form velocity measurements of flow. We use CBFv-fMRI in measure changes in blood velocity in single penetrating microvessels across rat parietal cortex. In contrast to the venule-dominated BOLD and arteriole-dominated CBV fMRI signals, CBFv-fMRI is comparable from both arterioles and venules. A single fMRI platform is used to map changes in blood pO2 (BOLD), volume (CBV), and velocity (CBFv). This combined high-resolution single-vessel fMRI mapping scheme enables vessel-specific hemodynamic mapping in animal models of normal and diseased states and further has translational potential to map vascular dementia in diseased or injured human brains with ultra-high-field fMRI.
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Affiliation(s)
- Xuming Chen
- High-Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- Department of Neurology, Wuhan University, Renmin Hospital, Wuhan, China
| | - Yuanyuan Jiang
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, United States of America
| | - Sangcheon Choi
- High-Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- Graduate Training Centre of Neuroscience, International Max Planck Research School, University of Tübingen, Tübingen, Germany
| | - Rolf Pohmann
- High-Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Klaus Scheffler
- High-Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- Department for Biomedical Magnetic Resonance, University of Tübingen, Tübingen, Germany
| | - David Kleinfeld
- Department of Physics, University of California at San Diego, La Jolla, California, United States of America
- Section of Neurobiology, University of California at San Diego, La Jolla, California, United States of America
| | - Xin Yu
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, United States of America
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107
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Zhang W, Davis CM, Zeppenfeld DM, Golgotiu K, Wang MX, Haveliwala M, Hong D, Li Y, Wang RK, Iliff JJ, Alkayed NJ. Role of endothelium-pericyte signaling in capillary blood flow response to neuronal activity. J Cereb Blood Flow Metab 2021; 41:1873-1885. [PMID: 33853406 PMCID: PMC8327110 DOI: 10.1177/0271678x211007957] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Local blood flow in the brain is tightly coupled to metabolic demands, a phenomenon termed functional hyperemia. Both capillaries and arterioles contribute to the hyperemic response to neuronal activity via different mechanisms and timescales. The nature and specific signaling involved in the hyperemic response of capillaries versus arterioles, and their temporal relationship are not fully defined. We determined the time-dependent changes in capillary flux and diameter versus arteriolar velocity and flow following whisker stimulation using optical microangiography (OMAG) and two-photon microscopy. We further characterized depth-resolved responses of individual capillaries versus capillary networks. We hypothesized that capillaries respond first to neuronal activation, and that they exhibit a coordinated response mediated via endothelial-derived epoxyeicosatrienoates (EETs) acting on pericytes. To visualize peri-capillary pericytes, we used Tie2-GFP/NG2-DsRed mice, and to determine the role of endothelial-derived EETs, we compared cerebrovascular responses to whisker stimulation between wild-type mice and mice with lower endothelial EETs (Tie2-hsEH). We found that capillaries respond immediately to neuronal activation in an orchestrated network-level manner, a response attenuated in Tie2-hsEH and inhibited by blocking EETs action on pericytes. These results demonstrate that capillaries are first responders during functional hyperemia, and that they exhibit a network-level response mediated via endothelial-derived EETs' action on peri-capillary pericytes.
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Affiliation(s)
- Wenri Zhang
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA
| | - Catherine M Davis
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA
| | - Douglas M Zeppenfeld
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA
| | - Kirsti Golgotiu
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA
| | - Marie X Wang
- Mental Illness Research, Education and Clinical Center, VA Puget Sound Health Care Center, Seattle, WA, USA.,Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, WA, USA
| | - Mariya Haveliwala
- Mental Illness Research, Education and Clinical Center, VA Puget Sound Health Care Center, Seattle, WA, USA.,Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, WA, USA
| | - Daniel Hong
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA
| | - Yuandong Li
- Department of Bioengineering, University of Washington School of Medicine, Seattle, WA, USA
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington School of Medicine, Seattle, WA, USA
| | - Jeffrey J Iliff
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA.,Mental Illness Research, Education and Clinical Center, VA Puget Sound Health Care Center, Seattle, WA, USA.,Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, WA, USA
| | - Nabil J Alkayed
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA.,Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA
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108
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Zhang Q, Gheres KW, Drew PJ. Origins of 1/f-like tissue oxygenation fluctuations in the murine cortex. PLoS Biol 2021; 19:e3001298. [PMID: 34264930 PMCID: PMC8282088 DOI: 10.1371/journal.pbio.3001298] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 05/24/2021] [Indexed: 01/07/2023] Open
Abstract
The concentration of oxygen in the brain spontaneously fluctuates, and the distribution of power in these fluctuations has a 1/f-like spectra, where the power present at low frequencies of the power spectrum is orders of magnitude higher than at higher frequencies. Though these oscillations have been interpreted as being driven by neural activity, the origin of these 1/f-like oscillations is not well understood. Here, to gain insight of the origin of the 1/f-like oxygen fluctuations, we investigated the dynamics of tissue oxygenation and neural activity in awake behaving mice. We found that oxygen signal recorded from the cortex of mice had 1/f-like spectra. However, band-limited power in the local field potential did not show corresponding 1/f-like fluctuations. When local neural activity was suppressed, the 1/f-like fluctuations in oxygen concentration persisted. Two-photon measurements of erythrocyte spacing fluctuations and mathematical modeling show that stochastic fluctuations in erythrocyte flow could underlie 1/f-like dynamics in oxygenation. These results suggest that the discrete nature of erythrocytes and their irregular flow, rather than fluctuations in neural activity, could drive 1/f-like fluctuations in tissue oxygenation.
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Affiliation(s)
- Qingguang Zhang
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- * E-mail: (QZ); (PJD)
| | - Kyle W. Gheres
- Graduate Program in Molecular Cellular and Integrative Biosciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Patrick J. Drew
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Neurosurgery, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- * E-mail: (QZ); (PJD)
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109
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Oka F, Sadeghian H, Yaseen MA, Fu B, Kura S, Qin T, Sakadžić S, Sugimoto K, Inoue T, Ishihara H, Nomura S, Suzuki M, Ayata C. Intracranial pressure spikes trigger spreading depolarizations. Brain 2021; 145:194-207. [PMID: 34245240 PMCID: PMC9126007 DOI: 10.1093/brain/awab256] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 05/29/2021] [Accepted: 06/17/2021] [Indexed: 01/09/2023] Open
Abstract
Spreading depolarizations are highly prevalent and spatiotemporally punctuated events worsening the outcome of brain injury. Trigger factors are poorly understood but may be linked to sudden worsening in supply-demand mismatch in compromised tissue. Sustained or transient elevations in intracranial pressure are also prevalent in the injured brain. Here, using a mouse model of large hemispheric ischaemic stroke, we show that mild and brief intracranial pressure elevations (20 or 30 mmHg for just 3 min) potently trigger spreading depolarizations in ischaemic penumbra (4-fold increase in spreading depolarization occurrence). We also show that 30 mmHg intracranial pressure spikes as brief as 30 s are equally effective. In contrast, sustained intracranial pressure elevations to the same level for 30 min do not significantly increase the spreading depolarization rate, suggesting that an abrupt disturbance in the steady state equilibrium is required to trigger a spreading depolarization. Laser speckle flowmetry consistently showed a reduction in tissue perfusion, and two-photon pO2 microscopy revealed a drop in venous pO2 during the intracranial pressure spikes suggesting increased oxygen extraction fraction, and therefore, worsening supply-demand mismatch. These haemodynamic changes during intracranial pressure spikes were associated with highly reproducible increases in extracellular potassium levels in penumbra. Consistent with the experimental data, a higher rate of intracranial pressure spikes was associated with spreading depolarization clusters in a retrospective series of patients with aneurysmal subarachnoid haemorrhage with strong temporal correspondence. Altogether, our data show that intracranial pressure spikes, even when mild and brief, are capable of triggering spreading depolarizations. Aggressive prevention of intracranial pressure spikes may help reduce spreading depolarization occurrence and improve outcomes after brain injury.
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Affiliation(s)
- Fumiaki Oka
- Neurovascular Research Laboratory, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA,Department of Neurosurgery, Yamaguchi Graduate School of Medicine, Ube, Yamaguchi, 755-8505, Japan,Correspondence to: Fumiaki Oka, MD, PhD Department of Neurosurgery, Yamaguchi Graduate School of Medicine 1-1-1, Minami-Kogushi, Ube, Yamaguchi, 755-8505, Japan E-mail:
| | - Homa Sadeghian
- Neurovascular Research Laboratory, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
| | - Mohammad A Yaseen
- Optics Division, MGH/MIT/HMS Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
| | - Buyin Fu
- Optics Division, MGH/MIT/HMS Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
| | - Sreekanth Kura
- Optics Division, MGH/MIT/HMS Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
| | - Tao Qin
- Neurovascular Research Laboratory, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
| | - Sava Sakadžić
- Optics Division, MGH/MIT/HMS Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
| | - Kazutaka Sugimoto
- Department of Neurosurgery, Yamaguchi Graduate School of Medicine, Ube, Yamaguchi, 755-8505, Japan
| | - Takao Inoue
- Department of Advanced ThermoNeuroBiology, Yamaguchi Graduate School of Medicine, Ube, Yamaguchi, 755-8505, Japan
| | - Hideyuki Ishihara
- Department of Neurosurgery, Yamaguchi Graduate School of Medicine, Ube, Yamaguchi, 755-8505, Japan
| | - Sadahiro Nomura
- Department of Neurosurgery, Yamaguchi Graduate School of Medicine, Ube, Yamaguchi, 755-8505, Japan
| | - Michiyasu Suzuki
- Department of Advanced ThermoNeuroBiology, Yamaguchi Graduate School of Medicine, Ube, Yamaguchi, 755-8505, Japan
| | - Cenk Ayata
- Neurovascular Research Laboratory, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA,Stroke Service, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA,Correspondence may also be addressed to: Cenk Ayata, MD, PhD Massachusetts General Hospital, 149 13th street, Room 6408, Charlestown, MA 02129, USA E-mail:
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110
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Bernier LP, Brunner C, Cottarelli A, Balbi M. Location Matters: Navigating Regional Heterogeneity of the Neurovascular Unit. Front Cell Neurosci 2021; 15:696540. [PMID: 34276312 PMCID: PMC8277940 DOI: 10.3389/fncel.2021.696540] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 05/31/2021] [Indexed: 12/27/2022] Open
Abstract
The neurovascular unit (NVU) of the brain is composed of multiple cell types that act synergistically to modify blood flow to locally match the energy demand of neural activity, as well as to maintain the integrity of the blood-brain barrier (BBB). It is becoming increasingly recognized that the functional specialization, as well as the cellular composition of the NVU varies spatially. This heterogeneity is encountered as variations in vascular and perivascular cells along the arteriole-capillary-venule axis, as well as through differences in NVU composition throughout anatomical regions of the brain. Given the wide variations in metabolic demands between brain regions, especially those of gray vs. white matter, the spatial heterogeneity of the NVU is critical to brain function. Here we review recent evidence demonstrating regional specialization of the NVU between brain regions, by focusing on the heterogeneity of its individual cellular components and briefly discussing novel approaches to investigate NVU diversity.
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Affiliation(s)
- Louis-Philippe Bernier
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Clément Brunner
- Neuro-Electronics Research Flanders, Leuven, Belgium.,Vlaams Instituut voor Biotechnologie, Leuven, Belgium.,Interuniversity Microeletronics Centre, Leuven, Belgium.,Department of Neurosciences, KU Leuven, Leuven, Belgium
| | | | - Matilde Balbi
- Queensland Brain Institute, University of Queensland, Brisbane, QLD, Australia
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111
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Abstract
The distribution of blood throughout the brain is facilitated by highly interconnected capillary networks. However, the steps involved in the construction of these networks has remained unclear. We used in vivo two-photon imaging through noninvasive cranial windows to study the engineering of capillary networks in the cerebral cortex of mouse neonates. We find that angiogenic activity originates at ascending venules, which undergo a burst of sprouting in the second postnatal week. This sprouting activity first establishes long paths to connect venules to blood input from neighboring arterioles, and then expands capillary interconnectivity with a multitude of short-range connections. Our study provides an experimental foundation to understand how capillary networks are shaped in the living mammalian brain during postnatal development. Capillary networks are essential for distribution of blood flow through the brain, and numerous other homeostatic functions, including neurovascular signal conduction and blood–brain barrier integrity. Accordingly, the impairment of capillary architecture and function lies at the root of many brain diseases. Visualizing how brain capillary networks develop in vivo can reveal innate programs for cerebrovascular growth and repair. Here, we use longitudinal two-photon imaging through noninvasive thinned skull windows to study a burst of angiogenic activity during cerebrovascular development in mouse neonates. We find that angiogenesis leading to the formation of capillary networks originated exclusively from cortical ascending venules. Two angiogenic sprouting activities were observed: 1) early, long-range sprouts that directly connected venules to upstream arteriolar input, establishing the backbone of the capillary bed, and 2) short-range sprouts that contributed to expansion of anastomotic connectivity within the capillary bed. All nascent sprouts were prefabricated with an intact endothelial lumen and pericyte coverage, ensuring their immediate perfusion and stability upon connection to their target vessels. The bulk of this capillary expansion spanned only 2 to 3 d and contributed to an increase of blood flow during a critical period in cortical development.
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112
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Tokunaga R, Paquette T, Tsurugizawa T, Leblond H, Piché M. Fasting prevents medetomidine-induced hyperglycaemia and alterations of neurovascular coupling in the somatosensory cortex of the rat during noxious stimulation. Eur J Neurosci 2021; 54:4906-4919. [PMID: 34137097 DOI: 10.1111/ejn.15350] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 05/30/2021] [Accepted: 06/10/2021] [Indexed: 11/28/2022]
Abstract
Medetomidine and isoflurane are commonly used for general anaesthesia in fMRI studies, but they alter cerebral blood flow (CBF) regulation and neurovascular coupling (NVC). In addition, medetomidine induces hypoinsulinemia and hyperglycaemia, which also alter CBF regulation and NVC. Furthermore, sudden changes in arterial pressure induced by noxious stimulation may affect NVC differently under medetomidine and isoflurane anaesthesia, considering their different effects on vascular functions. The first objective of this study was to compare NVC under medetomidine and isoflurane anaesthesia during noxious stimulation. The second objective was to examine whether fasting may improve NVC by reducing medetomidine-induced hyperglycaemia. In male Wister rats, noxious electrical stimulation was applied to the sciatic nerve in fasted or non-fasted animals. CBF and local field potentials (LFP) were recorded in the somatosensory cortex to assess NVC (CBF/LFP ratio). The CBF/LFP ratio was increased by medetomidine compared with isoflurane (p = 0.004), but this effect was abolished by fasting (p = 0.8). Accordingly, medetomidine produced a threefold increase in blood glucose (p < 0.001), but this effect was also abolished by fasting (p = 0.3). This indicates that isoflurane and medetomidine anaesthesia alter NVC differently, but the undesirable glucose dependent effects of medetomidine on NVC can be prevented by fasting.
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Affiliation(s)
- Ryota Tokunaga
- Department of Anatomy, Université du Québec à Trois-Rivières, Trois-Rivières, Quebec, Canada
| | - Thierry Paquette
- Department of Anatomy, Université du Québec à Trois-Rivières, Trois-Rivières, Quebec, Canada
| | - Tomokazu Tsurugizawa
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Hugues Leblond
- Department of Anatomy, Université du Québec à Trois-Rivières, Trois-Rivières, Quebec, Canada
| | - Mathieu Piché
- Department of Anatomy, Université du Québec à Trois-Rivières, Trois-Rivières, Quebec, Canada
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113
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Wang HL, Chen JW, Yang SH, Lo YC, Pan HC, Liang YW, Wang CF, Yang Y, Kuo YT, Lin YC, Chou CY, Lin SH, Chen YY. Multimodal Optical Imaging to Investigate Spatiotemporal Changes in Cerebrovascular Function in AUDA Treatment of Acute Ischemic Stroke. Front Cell Neurosci 2021; 15:655305. [PMID: 34149359 PMCID: PMC8209306 DOI: 10.3389/fncel.2021.655305] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 05/10/2021] [Indexed: 01/03/2023] Open
Abstract
Administration of 12-(3-adamantan-1-yl-ureido)-dodecanoic acid (AUDA) has been demonstrated to alleviate infarction following ischemic stroke. Reportedly, the main effect of AUDA is exerting anti-inflammation and neovascularization via the inhibition of soluble epoxide hydrolase. However, the major contribution of this anti-inflammation and neovascularization effect in the acute phase of stroke is not completely elucidated. To investigate the neuroprotective effects of AUDA in acute ischemic stroke, we combined laser speckle contrast imaging and optical intrinsic signal imaging techniques with the implantation of a lab-designed cranial window. Forepaw stimulation was applied to assess the functional changes via measuring cerebral metabolic rate of oxygen (CMRO2) that accompany neural activity. The rats that received AUDA in the acute phase of photothrombotic ischemia stroke showed a 30.5 ± 8.1% reduction in the ischemic core, 42.3 ± 15.1% reduction in the ischemic penumbra (p < 0.05), and 42.1 ± 4.6% increase of CMRO2 in response to forepaw stimulation at post-stroke day 1 (p < 0.05) compared with the control group (N = 10 for each group). Moreover, at post-stroke day 3, increased functional vascular density was observed in AUDA-treated rats (35.9 ± 1.9% higher than that in the control group, p < 0.05). At post-stroke day 7, a 105.4% ± 16.4% increase of astrocytes (p < 0.01), 30.0 ± 10.9% increase of neurons (p < 0.01), and 65.5 ± 15.0% decrease of microglia (p < 0.01) were observed in the penumbra region in AUDA-treated rats (N = 5 for each group). These results suggested that AUDA affects the anti-inflammation at the beginning of ischemic injury and restores neuronal metabolic rate of O2 and tissue viability. The neovascularization triggered by AUDA restored CBF and may contribute to ischemic infarction reduction at post-stroke day 3. Moreover, for long-term neuroprotection, astrocytes in the penumbra region may play an important role in protecting neurons from apoptotic injury.
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Affiliation(s)
- Han-Lin Wang
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Jia-Wei Chen
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Shih-Hung Yang
- Department of Mechanical Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Yu-Chun Lo
- The Ph.D. Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Han-Chi Pan
- National Laboratory Animal Center, Taipei, Taiwan
| | - Yao-Wen Liang
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Ching-Fu Wang
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Yi Yang
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Yun-Ting Kuo
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Yi-Chen Lin
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Chin-Yu Chou
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Sheng-Huang Lin
- Department of Neurology, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan.,Department of Neurology, School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - You-Yin Chen
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan.,The Ph.D. Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
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114
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Wang Z, Liu J, Liu X, Guo X, Li T, Pang R, Duan M. Perfusion microvessel density in the cerebral cortex of septic rats is negatively correlated with endothelial microparticles in circulating plasma. Metab Brain Dis 2021; 36:1029-1036. [PMID: 33625638 DOI: 10.1007/s11011-021-00702-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 02/17/2021] [Indexed: 10/22/2022]
Abstract
In sepsis, endothelial microparticles (EMPs) released from endothelial cells (ECs) participate in microcirculation dysfunction through pro-coagulant and pro-inflammatory effects, which can lead to sepsis-associated brain dysfunction. However, the relationship between EMPs and cerebral cortical perfusion microvessel density has not been explored. A closed cranial window was created in rats who were tended to until the cerebral cortex edema caused by preparation of the cranial window subsided, and the microvessel density was stable. A cecal ligation and puncture (CLP) sepsis procedure was then performed on day 6, post-surgery. At 12 and 24 h after the CLP, cerebral cortical perfusion microvessel density was measured with optical coherence tomography angiography (OCTA), followed by measurement of EMPs to evaluate the relationship between these factors. Microvessel density changed from 46.38 % ± 7.65 % on the day of surgery to 35.87 % ± 11.05 % on the second day and 36.71 % ± 11.38 % on the third day after surgery, and then increased daily. The microvessel density decreased to 27.20 % ± 8.50 % 24 h after CLP, which was significantly lower than that immediately and 12 h after CLP (P < 0.001). EMPs increased progressively at 12 and 24 h after CLP. Moreover, there was a negative correlation between EMPs and microvessel density (r=-0.56, P = 0.01). Edema and microvessel density decreased in the local cerebral cortex of the window and then gradually recovered after cranial window surgery. In sepsis, the perfusion microvessel density of the cerebral cortex negatively correlated with the EMPs. Therefore, the perfusion microvessel density can be indirectly evaluated by detecting the plasma EMP level.
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Affiliation(s)
- Zhenzhou Wang
- Department of Critical Care Medicine, Beijing Friendship Hospital, Capital Medical University, No. 95 Yong An Road, Xi Cheng District, Beijing, 100050, China
| | - Jingfeng Liu
- Department of Critical Care Medicine, Beijing Friendship Hospital, Capital Medical University, No. 95 Yong An Road, Xi Cheng District, Beijing, 100050, China
| | - Xi Liu
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, China
| | - Xinjie Guo
- Department of Critical Care Medicine, Beijing Friendship Hospital, Capital Medical University, No. 95 Yong An Road, Xi Cheng District, Beijing, 100050, China
| | - Tian Li
- Department of Critical Care Medicine, Beijing Friendship Hospital, Capital Medical University, No. 95 Yong An Road, Xi Cheng District, Beijing, 100050, China
| | - Ran Pang
- Department of Critical Care Medicine, Beijing Friendship Hospital, Capital Medical University, No. 95 Yong An Road, Xi Cheng District, Beijing, 100050, China
| | - Meili Duan
- Department of Critical Care Medicine, Beijing Friendship Hospital, Capital Medical University, No. 95 Yong An Road, Xi Cheng District, Beijing, 100050, China.
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115
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Sugashi T, Yuki H, Niizawa T, Takuwa H, Kanno I, Masamoto K. Three-dimensional microvascular network reconstruction from in vivo images with adaptation of the regional inhomogeneity in the signal-to-noise ratio. Microcirculation 2021; 28:e12697. [PMID: 33786951 DOI: 10.1111/micc.12697] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 02/19/2021] [Accepted: 03/22/2021] [Indexed: 11/27/2022]
Abstract
OBJECTIVE Quantification of angiographic images with two-photon laser scanning fluorescence microscopy (2PLSM) relies on proper segmentation of the vascular images. However, the images contain inhomogeneities in the signal-to-noise ratio (SNR) arising from regional effects of light scattering and absorption. The present study developed a semiautomated quantification method for volume images of 2PLSM angiography by adjusting the binarization threshold according to local SNR along the vessel centerlines. METHODS A phantom model made with fluorescent microbeads was used to incorporate a region-dependent binarization threshold. RESULTS The recommended SNR for imaging was found to be 4.2-10.6 that provide the true size of imaged objects if the binarization threshold was fixed at 50% of SNR. However, angiographic images in the mouse cortex showed variable SNR up to 45 over the depths. To minimize the errors caused by variable SNR and a spatial extent of the imaged objects in an axial direction, the microvascular networks were three-dimensionally reconstructed based on the cross-sectional diameters measured along the vessel centerline from the XY-plane images with adapted binarization threshold. The arterial volume was relatively constant over depths of 0-500 µm, and the capillary volume (1.7% relative to the scanned volume) showed the larger volumes than the artery (0.8%) and vein (0.6%). CONCLUSIONS The present methods allow consistent segmentation of microvasculature by adapting the local inhomogeneity in the SNR, which will be useful for quantitative comparison of the microvascular networks, such as under disease conditions where SNR in the 2PLSM images varies over space and time.
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Affiliation(s)
- Takuma Sugashi
- Department of Mechanical Engineering and Intelligent Systems, Graduate School of Informatics and Engineering, University of Electro-Communications, Chofu, Japan
| | - Hiroya Yuki
- Department of Mechanical Engineering and Intelligent Systems, Graduate School of Informatics and Engineering, University of Electro-Communications, Chofu, Japan
| | - Tomoya Niizawa
- Department of Mechanical Engineering and Intelligent Systems, Graduate School of Informatics and Engineering, University of Electro-Communications, Chofu, Japan
| | - Hiroyuki Takuwa
- Functional Brain Imaging Research, National Institute of Radiological Sciences, Chiba, Japan
| | - Iwao Kanno
- Functional Brain Imaging Research, National Institute of Radiological Sciences, Chiba, Japan
| | - Kazuto Masamoto
- Department of Mechanical Engineering and Intelligent Systems, Graduate School of Informatics and Engineering, University of Electro-Communications, Chofu, Japan.,Functional Brain Imaging Research, National Institute of Radiological Sciences, Chiba, Japan.,Center for Neuroscience and Biomedical Engineering, University of Electro-Communications, Chofu, Japan
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116
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Brain capillary pericytes exert a substantial but slow influence on blood flow. Nat Neurosci 2021; 24:633-645. [PMID: 33603231 PMCID: PMC8102366 DOI: 10.1038/s41593-020-00793-2] [Citation(s) in RCA: 204] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 12/23/2020] [Indexed: 01/30/2023]
Abstract
The majority of the brain's vasculature is composed of intricate capillary networks lined by capillary pericytes. However, it remains unclear whether capillary pericytes influence blood flow. Using two-photon microscopy to observe and manipulate brain capillary pericytes in vivo, we find that their optogenetic stimulation decreases lumen diameter and blood flow, but with slower kinetics than similar stimulation of mural cells on upstream pial and precapillary arterioles. This slow vasoconstriction was inhibited by the clinically used vasodilator fasudil, a Rho-kinase inhibitor that blocks contractile machinery. Capillary pericytes were also slower to constrict back to baseline following hypercapnia-induced dilation, and slower to dilate towards baseline following optogenetically induced vasoconstriction. Optical ablation of single capillary pericytes led to sustained local dilation and a doubling of blood cell flux selectively in capillaries lacking pericyte contact. These data indicate that capillary pericytes contribute to basal blood flow resistance and slow modulation of blood flow throughout the brain.
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117
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Andoh M, Koyama R. Assessing Microglial Dynamics by Live Imaging. Front Immunol 2021; 12:617564. [PMID: 33763064 PMCID: PMC7982483 DOI: 10.3389/fimmu.2021.617564] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 02/16/2021] [Indexed: 12/13/2022] Open
Abstract
Microglia are highly dynamic in the brain in terms of their ability to migrate, proliferate, and phagocytose over the course of an individual's life. Real-time imaging is a useful tool to examine how microglial behavior is regulated and how it affects the surrounding environment. However, microglia are sensitive to environmental stimuli, so they possibly change their state during live imaging in vivo, mainly due to surgical damage, and in vitro due to various effects associated with culture conditions. Therefore, it is difficult to perform live imaging without compromising the properties of the microglia under physiological conditions. To overcome this barrier, various experimental conditions have been developed; recently, it has become possible to perform live imaging of so-called surveillant microglia in vivo, ex vivo, and in vitro, although there are various limitations. Now, we can choose in vivo, ex vivo, or in vitro live imaging systems according to the research objective. In this review, we discuss the advantages and disadvantages of each experimental system and outline the physiological significance and molecular mechanisms of microglial behavior that have been elucidated by live imaging.
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Affiliation(s)
- Megumi Andoh
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Ryuta Koyama
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
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118
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McDowell KP, Berthiaume AA, Tieu T, Hartmann DA, Shih AY. VasoMetrics: unbiased spatiotemporal analysis of microvascular diameter in multi-photon imaging applications. Quant Imaging Med Surg 2021; 11:969-982. [PMID: 33654670 PMCID: PMC7829163 DOI: 10.21037/qims-20-920] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 11/17/2020] [Indexed: 01/13/2023]
Abstract
BACKGROUND Multi-photon imaging of the cerebrovasculature provides rich data on the dynamics of cortical arterioles, capillaries, and venules. Vascular diameter is the major determinant of blood flow resistance, and is the most commonly quantified metric in studies of the cerebrovasculature. However, there is a lack of accessible and easy-to-use methods to quantify vascular diameter in imaging data. METHODS We created VasoMetrics, a macro written in ImageJ/Fiji for spatiotemporal analysis of microvascular diameter. The key feature of VasoMetrics is rapid analysis of many evenly spaced cross-sectional lines along the vessel of interest, permitting the extraction of numerous diameter measurements from individual vessels. Here we demonstrated the utility of VasoMetrics by analyzing in vivo multi-photon imaging stacks and movies collected from lightly sedated mice, as well as data from optical coherence tomography angiography (OCTA) of human retina. RESULTS Compared to the standard approach, which is to measure cross-sectional diameters at arbitrary points along a vessel, VasoMetrics accurately reported spatiotemporal features of vessel diameter, reduced measurement bias and time spent analyzing data, and improved the reproducibility of diameter measurements between users. VasoMetrics revealed the dynamics in pial arteriole diameters during vasomotion at rest, as well as changes in capillary diameter before and after pericyte ablation. Retinal arteriole diameter was quantified from a human retinal angiogram, providing proof-of-principle that VasoMetrics can be applied to contrast-enhanced clinical imaging of microvasculature. CONCLUSIONS VasoMetrics is a robust macro for spatiotemporal analysis of microvascular diameter in imaging applications.
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Affiliation(s)
- Konnor P. McDowell
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, WA, USA
| | - Andrée-Anne Berthiaume
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, WA, USA
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Taryn Tieu
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, WA, USA
| | - David A. Hartmann
- Department of Neurology & Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Andy Y. Shih
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, WA, USA
- Department of Pediatrics, University of Washington, Seattle, WA, USA
- Department of Bioengineering, University of Washington, Seattle, WA, USA
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119
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Rolfes L, Riek-Burchardt M, Pawlitzki M, Minnerup J, Bock S, Schmidt M, Meuth SG, Gunzer M, Neumann J. Neutrophil granulocytes promote flow stagnation due to dynamic capillary stalls following experimental stroke. Brain Behav Immun 2021; 93:322-330. [PMID: 33486002 DOI: 10.1016/j.bbi.2021.01.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 01/08/2021] [Accepted: 01/11/2021] [Indexed: 12/01/2022] Open
Abstract
Flow stagnation of peri-ischemic capillaries due to dynamic leukocyte stalls has been described to be a contributor to ongoing penumbral injury in transient brain ischemia, but has not been investigated in permanent experimental stroke so far. Moreover, it is discussed that obstructing neutrophils are involved in this process; however, their contribution has not yet been proven. Here, we characterize the dynamics of neutrophil granulocytes in two models of permanent stroke (photothrombosis and permanent middle cerebral artery occlusion) using intravital two-photon fluorescence microscopy. Different to previous studies on LysM-eGFP+ cells we additionally apply a transgenic mouse model with tdTomato-expressing neutrophils to avoid interference from additional immune cell subsets. We identify repetitively occurring capillary stalls of varying duration promoted by neutrophils in both models of permanent cerebral ischemia, validating the suitability of our new transgenic mouse model in determining neutrophil occlusion formation in vivo. Flow cytometric analysis of peripheral blood (PB) and brain tissue from mice subjected to photothrombosis reveal an increase in the total proportion of neutrophils, with selective upregulation of endothelial adherence markers in the PB. In conclusion, the dynamic microcirculatory stall phenomenon that is described after transient ischemia followed by reperfusion also occurs after permanent small- or large-vessel stroke and is clearly attributable to neutrophils.
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Affiliation(s)
- Leoni Rolfes
- Department of Neurology with Institute of Translational Neurology, University Hospital Münster, Germany.
| | | | - Marc Pawlitzki
- Department of Neurology with Institute of Translational Neurology, University Hospital Münster, Germany; Department of Neurology, Otto-von-Guericke University, Magdeburg, Germany.
| | - Jens Minnerup
- Department of Neurology with Institute of Translational Neurology, University Hospital Münster, Germany.
| | - Stefanie Bock
- Department of Neurology with Institute of Translational Neurology, University Hospital Münster, Germany.
| | - Mariella Schmidt
- Department of Neurology with Institute of Translational Neurology, University Hospital Münster, Germany.
| | - Sven G Meuth
- Department of Neurology with Institute of Translational Neurology, University Hospital Münster, Germany; Department of Neurology, University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, Germany.
| | - Matthias Gunzer
- Institute for Experimental Immunology and Imaging, University Hospital Essen, Germany.
| | - Jens Neumann
- Department of Neurology, Otto-von-Guericke University, Magdeburg, Germany.
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120
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Yasukagawa M, Shimada A, Shiozaki S, Tobita S, Yoshihara T. Phosphorescent Ir(III) complexes conjugated with oligoarginine peptides serve as optical probes for in vivo microvascular imaging. Sci Rep 2021; 11:4733. [PMID: 33637825 PMCID: PMC7910296 DOI: 10.1038/s41598-021-84115-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 01/27/2021] [Indexed: 02/06/2023] Open
Abstract
Imaging the vascular structures of organ and tumor tissues is extremely important for assessing various pathological conditions. Herein we present the new vascular imaging probe BTQ-Rn (n = 8, 12, 16), a phosphorescent Ir(III) complex containing an oligoarginine peptide as a ligand. This microvasculature staining probe can be chemically synthesized, unlike the commonly used tomato lectins labeled with a fluorophore such as fluorescein isothiocyanate (FITC). Intravenous administration of BTQ-R12 to mice and subsequent confocal luminescence microscope measurements enabled in vivo vascular imaging of tumors and various organs, including kidney, liver and pancreas. Dual color imaging of hepatic tissues of living mice fed a high-fat diet using BTQ-R12 and the lipid droplet-specific probe PC6S revealed small and large lipid droplets in the hepatocytes, causing distortion of the sinusoidal structure. BTQ-R12 selectively stains vascular endothelium and thus allows longer-term vascular network imaging compared to fluorescent dextran with a molecular weight of 70 kDa that circulate in the bloodstream. Furthermore, time-gated measurements using this phosphorescent vascular probe enabled imaging of blood vessel structures without interference from autofluorescence.
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Affiliation(s)
- Mami Yasukagawa
- grid.256642.10000 0000 9269 4097Department of Chemistry and Chemical Biology, Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515 Japan
| | - Aya Shimada
- grid.256642.10000 0000 9269 4097Department of Chemistry and Chemical Biology, Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515 Japan
| | - Shuichi Shiozaki
- grid.256642.10000 0000 9269 4097Department of Chemistry and Chemical Biology, Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515 Japan
| | - Seiji Tobita
- grid.256642.10000 0000 9269 4097Department of Chemistry and Chemical Biology, Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515 Japan
| | - Toshitada Yoshihara
- grid.256642.10000 0000 9269 4097Department of Chemistry and Chemical Biology, Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515 Japan
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121
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Hartung G, Badr S, Moeini M, Lesage F, Kleinfeld D, Alaraj A, Linninger A. Voxelized simulation of cerebral oxygen perfusion elucidates hypoxia in aged mouse cortex. PLoS Comput Biol 2021; 17:e1008584. [PMID: 33507970 PMCID: PMC7842915 DOI: 10.1371/journal.pcbi.1008584] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 11/30/2020] [Indexed: 12/13/2022] Open
Abstract
Departures of normal blood flow and metabolite distribution from the cerebral microvasculature into neuronal tissue have been implicated with age-related neurodegeneration. Mathematical models informed by spatially and temporally distributed neuroimage data are becoming instrumental for reconstructing a coherent picture of normal and pathological oxygen delivery throughout the brain. Unfortunately, current mathematical models of cerebral blood flow and oxygen exchange become excessively large in size. They further suffer from boundary effects due to incomplete or physiologically inaccurate computational domains, numerical instabilities due to enormous length scale differences, and convergence problems associated with condition number deterioration at fine mesh resolutions. Our proposed simple finite volume discretization scheme for blood and oxygen microperfusion simulations does not require expensive mesh generation leading to the critical benefit that it drastically reduces matrix size and bandwidth of the coupled oxygen transfer problem. The compact problem formulation yields rapid and stable convergence. Moreover, boundary effects can effectively be suppressed by generating very large replica of the cortical microcirculation in silico using an image-based cerebrovascular network synthesis algorithm, so that boundaries of the perfusion simulations are far removed from the regions of interest. Massive simulations over sizeable portions of the cortex with feature resolution down to the micron scale become tractable with even modest computer resources. The feasibility and accuracy of the novel method is demonstrated and validated with in vivo oxygen perfusion data in cohorts of young and aged mice. Our oxygen exchange simulations quantify steep gradients near penetrating blood vessels and point towards pathological changes that might cause neurodegeneration in aged brains. This research aims to explain mechanistic interactions between anatomical structures and how they might change in diseases or with age. Rigorous quantification of age-related changes is of significant interest because it might aide in the search for imaging biomarkers for dementia and Alzheimer’s disease. Brain function critically depends on the maintenance of physiological blood supply and metabolism in the cortex. Disturbances to adequate perfusion have been linked to age-related neurodegeneration. However, the precise correlation between age-related hemodynamic changes and the resulting decline in oxygen delivery is not well understood and has not been quantified. Therefore, we introduce a new compact, and therefore highly scalable, computational method for predicting the physiological relationship between hemodynamics and cortical oxygen perfusion for large sections of the cortical microcirculation. We demonstrate the novel mesh generation-free (MGF), multi-scale simulation approach through realistic in vivo case studies of cortical microperfusion in the mouse brain. We further validate mechanistic correlations and a quantitative relationship between blood flow and brain oxygenation using experimental data from cohorts of young, middle aged and old mouse brains. Our computational approach overcomes size and performance limitations of previous unstructured meshing techniques to enable the prediction of oxygen tension with a spatial resolution of least two orders of magnitude higher than previously possible. Our simulation results support the hypothesis that structural changes in the microvasculature induce hypoxic pockets in the aged brain that are absent in the healthy, young mouse.
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Affiliation(s)
- Grant Hartung
- Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Shoale Badr
- Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Mohammad Moeini
- Polytechnique Montréal, Department of Electrical Engineering, Montreal, Canada
| | - Frédéric Lesage
- Polytechnique Montréal, Department of Electrical Engineering, Montreal, Canada
| | - David Kleinfeld
- Department of Physics, University of California San Diego, San Diego, California, United States of America
| | - Ali Alaraj
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Andreas Linninger
- Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois, United States of America
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois, United States of America
- * E-mail:
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122
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Underly RG, Shih AY. Rapid, Nitric Oxide Synthesis-Dependent Activation of MMP-9 at Pericyte Somata During Capillary Ischemia in vivo. Front Physiol 2021; 11:619230. [PMID: 33505320 PMCID: PMC7830159 DOI: 10.3389/fphys.2020.619230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 12/10/2020] [Indexed: 11/28/2022] Open
Abstract
Nitric oxide serves essential roles in normal vascular physiology, but paradoxically contributes to vascular pathology in disease. During brain ischemia, aberrant nitric oxide levels can cause cellular injury through induction of nitrosative/oxidative stress and post-translational activation of matrix-metalloproteinase-9 (MMP-9). We recently demonstrated that brain pericyte somata were associated with very early and localized MMP-9 activation along capillaries during cerebral ischemia, leading to focal blood-brain barrier disruption. Here, we tested whether this effect was dependent upon nitric oxide production. In vivo two-photon imaging was used to directly visualize MMP9 activity using a FITC-gelatin probe and leakage of intravenous dye during photothrombotically induced capillary ischemia. Results showed that the NOS inhibitor, L-NIL, at concentrations affecting both iNOS and constitutive NOS isoforms, attenuated capillary leakage at pericyte soma-specific locations and substantially reduced FITC-gelatin cleavage. We also found that combined administration of L-NIL and anisomycin, an inhibitor of protein synthesis, led to near complete elimination of FITC-gelatin cleavage and vascular leakage. These results indicate that both nitric oxide synthase and new protein synthesis are involved in the rapid activation of MMP-9 at somata of capillary pericytes during ischemia.
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Affiliation(s)
- Robert G Underly
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States
| | - Andy Y Shih
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States.,Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, United States.,Department of Pediatrics, University of Washington, Seattle, WA, United States.,Department of Bioengineering, University of Washington, Seattle, WA, United States
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123
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Network community structure and resilience to localized damage: Application to brain microcirculation. BRAIN MULTIPHYSICS 2021. [DOI: 10.1016/j.brain.2021.100028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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124
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Transcranial chronic optical access to longitudinally measure cerebral blood flow. J Neurosci Methods 2020; 350:109044. [PMID: 33340556 DOI: 10.1016/j.jneumeth.2020.109044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 12/10/2020] [Accepted: 12/11/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND The regulation of cerebral blood flow is critical for normal brain functioning, and many physiological and pathological conditions can have long-term impacts on cerebral blood flow. However, minimally invasive tools to study chronic changes in animal models are limited. NEW METHOD We developed a minimally invasive surgical technique (cyanoacrylate skull, CAS) allowing us to image cerebral blood flow longitudinally through the intact mouse skull using laser speckle imaging. RESULTS With CAS we were able to detect acute changes in cerebral blood flow induced by hypercapnic challenge. We were also able to image cerebral blood flow dynamics with laser speckle imaging for over 100 days. Furthermore, the relative cerebral blood flow remained stable in mice from 30 days to greater than 100 days after the surgery. COMPARISON WITH EXISTING METHODS Previously, achieving continuous long-term optical access to measure cerebral blood flow in individual vessels in a mouse model involved invasive surgery. In contrast, the CAS technique presented here is relatively non-invasive, as it allows stable optical access through an intact mouse skull. CONCLUSIONS The CAS technique allows researcher to chronically measure cerebral blood flow dynamics for a significant portion of a mouse's lifespan. This approach may be useful for studying changes in blood flow due to cerebral pathology or for examining the therapeutic effects of modifying cerebral blood flow in mouse models relevant to human disease.
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125
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Imaging and optogenetic modulation of vascular mural cells in the live brain. Nat Protoc 2020; 16:472-496. [PMID: 33299155 DOI: 10.1038/s41596-020-00425-w] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 09/24/2020] [Indexed: 12/17/2022]
Abstract
Mural cells (smooth muscle cells and pericytes) are integral components of brain blood vessels that play important roles in vascular formation, blood-brain barrier maintenance, and regulation of regional cerebral blood flow (rCBF). These cells are implicated in conditions ranging from developmental vascular disorders to age-related neurodegenerative diseases. Here we present complementary tools for cell labeling with transgenic mice and organic dyes that allow high-resolution intravital imaging of the different mural cell subtypes. We also provide detailed methodologies for imaging of spontaneous and neural activity-evoked calcium transients in mural cells. In addition, we describe strategies for single- and two-photon optogenetics that allow manipulation of the activity of individual and small clusters of mural cells. Together with measurements of diameter and flow in individual brain microvessels, calcium imaging and optogenetics allow the investigation of pericyte and smooth muscle cell physiology and their role in regulating rCBF. We also demonstrate the utility of these tools to investigate mural cells in the context of Alzheimer's disease and cerebral ischemia mouse models. Thus, these methods can be used to reveal the functional and structural heterogeneity of mural cells in vivo, and allow detailed cellular studies of the normal function and pathophysiology of mural cells in a variety of disease models. The implementation of this protocol can take from several hours to days depending on the intended applications.
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126
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Watson AN, Berthiaume AA, Faino AV, McDowell KP, Bhat NR, Hartmann DA, Shih AY. Mild pericyte deficiency is associated with aberrant brain microvascular flow in aged PDGFRβ +/- mice. J Cereb Blood Flow Metab 2020; 40:2387-2400. [PMID: 31987006 PMCID: PMC7820684 DOI: 10.1177/0271678x19900543] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The receptor tyrosine kinase PDGFRβ is essential for pericyte migration to the endothelium. In mice lacking one allele of PDGFRβ (PDGFRβ+/-), previous reports have described an age-dependent loss of pericytes in the brain, leading to cerebrovascular dysfunction and subsequent neurodegeneration reminiscent of that seen in Alzheimer's disease and vascular dementia. We examined 12-20-month-old PDGFRβ+/- mice to better understand how pericyte loss affects brain microvascular structure and perfusion in vivo. We observed a mild reduction of cortical pericyte number in PDGFRβ+/- mice (27% fewer cell bodies) compared to controls, but no decrease in pericyte coverage of the endothelium. This mild degree of pericyte loss caused no discernable change in cortical microvascular density, length, basal diameter or reactivity to hypercapnia. Yet, it was associated with an increase in basal blood cell velocity, primarily in pre-capillary arterioles. Taken together, our results suggest that mild pericyte loss can lead to aberrant cerebral blood flow despite a lack of apparent effect on microvascular structure and reactivity.
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Affiliation(s)
- Ashley N Watson
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Andree-Anne Berthiaume
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA.,Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, USA
| | - Anna V Faino
- Children's Core for Biomedical Statistics, Seattle Children's Research Institute, Seattle, WA, USA
| | - Konnor P McDowell
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA.,Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, USA
| | - Narayan R Bhat
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - David A Hartmann
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Andy Y Shih
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA.,Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, USA.,Children's Core for Biomedical Statistics, Seattle Children's Research Institute, Seattle, WA, USA.,Department of Pediatrics, University of Washington, Seattle, WA, USA
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127
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Fan JL, Rivera JA, Sun W, Peterson J, Haeberle H, Rubin S, Ji N. High-speed volumetric two-photon fluorescence imaging of neurovascular dynamics. Nat Commun 2020; 11:6020. [PMID: 33243995 PMCID: PMC7693336 DOI: 10.1038/s41467-020-19851-1] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 10/13/2020] [Indexed: 02/02/2023] Open
Abstract
Understanding the structure and function of vasculature in the brain requires us to monitor distributed hemodynamics at high spatial and temporal resolution in three-dimensional (3D) volumes in vivo. Currently, a volumetric vasculature imaging method with sub-capillary spatial resolution and blood flow-resolving speed is lacking. Here, using two-photon laser scanning microscopy (TPLSM) with an axially extended Bessel focus, we capture volumetric hemodynamics in the awake mouse brain at a spatiotemporal resolution sufficient for measuring capillary size and blood flow. With Bessel TPLSM, the fluorescence signal of a vessel becomes proportional to its size, which enables convenient intensity-based analysis of vessel dilation and constriction dynamics in large volumes. We observe entrainment of vasodilation and vasoconstriction with pupil diameter and measure 3D blood flow at 99 volumes/second. Demonstrating high-throughput monitoring of hemodynamics in the awake brain, we expect Bessel TPLSM to make broad impacts on neurovasculature research.
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Affiliation(s)
- Jiang Lan Fan
- University of California, Berkeley, CA, USA.,University of California, San Francisco, CA, USA
| | - Jose A Rivera
- Department of Physics, University of California, Berkeley, CA, USA
| | - Wei Sun
- Thorlabs Imaging Systems, Sterling, VA, USA
| | | | | | - Sam Rubin
- Thorlabs Imaging Systems, Sterling, VA, USA.,LightPath Technologies Inc., Orlando, FL, USA
| | - Na Ji
- Department of Physics, University of California, Berkeley, CA, USA. .,Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA. .,Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA. .,Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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128
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Validation of red blood cell flux and velocity estimations based on optical coherence tomography intensity fluctuations. Sci Rep 2020; 10:19584. [PMID: 33177606 PMCID: PMC7658245 DOI: 10.1038/s41598-020-76774-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Accepted: 11/02/2020] [Indexed: 01/03/2023] Open
Abstract
We present a validation of red blood cell flux and speed measurements based on the passage of erythrocytes through the OCT’s focal volume. We compare the performance of the so-called RBC-passage OCT technique to co-localized and simultaneously acquired two-photon excitation fluorescence microscopy (TPEF) measurements. Using concurrent multi-modal imaging, we show that fluctuations in the OCT signal display highly similar features to TPEF time traces. Furthermore, we demonstrate an overall difference in RBC flux and speed of 2.5 ± 3.27 RBC/s and 0.12 ± 0.67 mm/s (mean ± S.D.), compared to TPEF. The analysis also revealed that the OCT RBC flux estimation is most accurate between 20 RBC/s to 60 RBC/s, and is severely underestimated at fluxes beyond 80 RBC/s. Lastly, our analysis shows that the RBC speed estimations increase in accuracy as the speed decreases, reaching a difference of 0.16 ± 0.25 mm/s within the 0–0.5 mm/s speed range.
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129
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Turner KL, Gheres KW, Proctor EA, Drew PJ. Neurovascular coupling and bilateral connectivity during NREM and REM sleep. eLife 2020; 9:62071. [PMID: 33118932 PMCID: PMC7758068 DOI: 10.7554/elife.62071] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 10/28/2020] [Indexed: 12/11/2022] Open
Abstract
To understand how arousal state impacts cerebral hemodynamics and neurovascular coupling, we monitored neural activity, behavior, and hemodynamic signals in un-anesthetized, head-fixed mice. Mice frequently fell asleep during imaging, and these sleep events were interspersed with periods of wake. During both NREM and REM sleep, mice showed large increases in cerebral blood volume ([HbT]) and arteriole diameter relative to the awake state, two to five times larger than those evoked by sensory stimulation. During NREM, the amplitude of bilateral low-frequency oscillations in [HbT] increased markedly, and coherency between neural activity and hemodynamic signals was higher than the awake resting and REM states. Bilateral correlations in neural activity and [HbT] were highest during NREM, and lowest in the awake state. Hemodynamic signals in the cortex are strongly modulated by arousal state, and changes during sleep are substantially larger than sensory-evoked responses.
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Affiliation(s)
- Kevin L Turner
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, United States.,Center for Neural Engineering, The Pennsylvania State University, University Park, United States
| | - Kyle W Gheres
- Center for Neural Engineering, The Pennsylvania State University, University Park, United States.,Graduate Program in Molecular, Cellular, and Integrative Biosciences, The Pennsylvania State University, University Park, United States
| | - Elizabeth A Proctor
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, United States.,Center for Neural Engineering, The Pennsylvania State University, University Park, United States.,Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, United States.,Department of Neurosurgery, Penn State College of Medicine, Hershey, United States.,Department of Pharmacology, Penn State College of Medicine, Hershey, United States
| | - Patrick J Drew
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, United States.,Center for Neural Engineering, The Pennsylvania State University, University Park, United States.,Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, United States.,Department of Neurosurgery, Penn State College of Medicine, Hershey, United States
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130
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Marques Neto SR, Castiglione RC, da Silva TCB, Paes LDS, Pontes A, Oliveira DF, Ferraz EB, Ade Caldas CC, Nascimento JHM, Bouskela E. Effects of high intensity interval training on neuro-cardiovascular dynamic changes and mitochondrial dysfunction induced by high-fat diet in rats. PLoS One 2020; 15:e0240060. [PMID: 33095799 PMCID: PMC7584217 DOI: 10.1371/journal.pone.0240060] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 09/18/2020] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND AND AIMS Mitochondrial swelling is involved in the pathogenesis of many human diseases associated with oxidative stress including obesity. One of the strategies for prevention of deleterious effects related to obesity and overweight is engaging in regular physical activity, of which high intensity interval training (HIIT) is efficient in promoting biogenesis and improving the function of mitochondria. Therefore, our aims were to investigate the effects of HIIT on metabolic and neuro-cardiovascular dynamic control and mitochondrial swelling induced by high-fat diet (HFD). METHODS AND RESULTS Twenty-three male Wistar rats (60 - 80g) were divided into 4 subgroups: control (C), HIIT, HFD and HFD+HIIT. The whole experimentation period lasted for 22 weeks and HIIT sessions were performed 5 days a week during the last 4 weeks. At the end of the experiments, fasting glucose and insulin tolerance tests were performed. Cerebral microcirculation was analyzed using cortical intravital microscopy for capillary diameter and functional density. Cardiac function and ergoespirometric parameters were also investigated. Mitochondrial swelling was evaluated on brain and heart extracts. HFD promoted an increase on body adiposity (p<0.001), fasting glucose levels (p<0.001), insulin resistance index (p<0.05), cardiac hypertrophy index (p<0.05) and diastolic blood pressure (p<0.05), along with worsened cardiac function (p<0.05), reduced functional cerebral capillary density (p<0.05) and its diameter (p<0.01), and heart and brain mitochondrial function (p<0.001). HFD did not affect any ergoespirometric parameter. After 4 weeks of training, HIIT was able to improve cardiac hypertrophy index, diastolic blood pressure, cerebral functional capillary density (p<0.01) and heart and brain mitochondrial swelling (p<0.001). CONCLUSION In animals subjected to HFD, HIIT ameliorated both cerebral mitochondrial swelling and functional capillary density, but it did not improve cardiovascular function suggesting that the cardiovascular dysfunction elicited by HFD was not due to heart mitochondrial swelling.
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Affiliation(s)
- Silvio R. Marques Neto
- Laboratory for Clinical and Experimental Research on Vascular Biology (BioVasc), Biomedical Center, State University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
- Physical Activity Sciences Laboratory (LACAF), Physical Activity Sciences Postgraduate Program, Salgado de Oliveira University (UNIVERSO), Niteroi, RJ, Brazil
- Exercise Physiology Laboratory, School of Physical Education, Estácio de Sá University, Rio de Janeiro, RJ, Brazil
- Health Science School, Universidade do Grande Rio, Duque de Caxias, RJ, Brazil
| | - Raquel C. Castiglione
- Laboratory for Clinical and Experimental Research on Vascular Biology (BioVasc), Biomedical Center, State University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Teresa C. B. da Silva
- Laboratory for Clinical and Experimental Research on Vascular Biology (BioVasc), Biomedical Center, State University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
- Health Science School, Universidade do Grande Rio, Duque de Caxias, RJ, Brazil
| | - Lorena da S. Paes
- Laboratory for Clinical and Experimental Research on Vascular Biology (BioVasc), Biomedical Center, State University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Aiza Pontes
- Laboratory for Clinical and Experimental Research on Vascular Biology (BioVasc), Biomedical Center, State University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Dahienne F. Oliveira
- Cardiac Electrophysiology Laboratory, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Emanuelle B. Ferraz
- Cardiac Electrophysiology Laboratory, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Carla Christina Ade Caldas
- Physical Activity Sciences Laboratory (LACAF), Physical Activity Sciences Postgraduate Program, Salgado de Oliveira University (UNIVERSO), Niteroi, RJ, Brazil
| | - José Hamilton M. Nascimento
- Cardiac Electrophysiology Laboratory, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Eliete Bouskela
- Laboratory for Clinical and Experimental Research on Vascular Biology (BioVasc), Biomedical Center, State University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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131
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Takahashi T, Zhang H, Kawakami R, Yarinome K, Agetsuma M, Nabekura J, Otomo K, Okamura Y, Nemoto T. PEO-CYTOP Fluoropolymer Nanosheets as a Novel Open-Skull Window for Imaging of the Living Mouse Brain. iScience 2020; 23:101579. [PMID: 33083745 PMCID: PMC7554658 DOI: 10.1016/j.isci.2020.101579] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/20/2020] [Accepted: 09/15/2020] [Indexed: 01/30/2023] Open
Abstract
In vivo two-photon deep imaging with a broad field of view has revealed functional connectivity among brain regions. Here, we developed a novel observation method that utilizes a polyethylene-oxide-coated CYTOP (PEO-CYTOP) nanosheet with a thickness of ∼130 nm that exhibited a water retention effect and a hydrophilized adhesive surface. PEO-CYTOP nanosheets firmly adhered to brain surfaces, which suppressed bleeding from superficial veins. By taking advantage of the excellent optical properties of PEO-CYTOP nanosheets, we performed in vivo deep imaging in mouse brains at high resolution. Moreover, PEO-CYTOP nanosheets enabled to prepare large cranial windows, achieving in vivo imaging of neural structure and Ca2+ elevation in a large field of view. Furthermore, the PEO-CYTOP nanosheets functioned as a sealing material, even after the removal of the dura. These results indicate that this method would be suitable for the investigation of neural functions that are composed of interactions among multiple regions. PEO-CYTOP nanosheet enables in vivo deep brain imaging in a vast field of view The 130 nm thickness and the hydrophilized surface realize the strong adhesiveness Suppressions of bleeding from the surface and inflammation in long-term are achieved The vast and transparent cranial window with natural curvature of the surface
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Affiliation(s)
- Taiga Takahashi
- Biophotonics Research Group, Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Higashiyama 5-1, Myodaiji, Okazaki, Aichi 444-8787, Japan.,Division of Biophotonics, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Higashiyama 5-1, Myodaiji, Okazaki, Aichi 444-8787, Japan.,School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Higashiyama 5-1, Myodaiji, Okazaki, Aichi 444-8787, Japan.,Research Institute for Electronic Science, Hokkaido University, Hokkaido, Kita 20 Nishi 10, Kita-ku, Sapporo, Hokkaido 001-0020, Japan.,Graduate School of Information Science and Technology Hokkaido University, Hokkaido, Kita 20 Nishi 10, Kita-ku, Sapporo, Hokkaido 001-0020, Japan
| | - Hong Zhang
- Department of Applied Chemistry, School of Engineering, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292, Japan.,Micro/Nano Technology Center, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292, Japan
| | - Ryosuke Kawakami
- Research Institute for Electronic Science, Hokkaido University, Hokkaido, Kita 20 Nishi 10, Kita-ku, Sapporo, Hokkaido 001-0020, Japan.,Graduate School of Information Science and Technology Hokkaido University, Hokkaido, Kita 20 Nishi 10, Kita-ku, Sapporo, Hokkaido 001-0020, Japan.,Department of Molecular Medicine for Pathogenesis, Graduate School of Medicine Ehime University, Shitsukawa 454, Toon, Ehime 791-0295, Japan
| | - Kenji Yarinome
- Course of Applied Science, Graduate School of Engineering, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292, Japan
| | - Masakazu Agetsuma
- Division of Homeostatic Development, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, 444-8585, Japan
| | - Junichi Nabekura
- School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Higashiyama 5-1, Myodaiji, Okazaki, Aichi 444-8787, Japan.,Division of Homeostatic Development, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, 444-8585, Japan
| | - Kohei Otomo
- Biophotonics Research Group, Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Higashiyama 5-1, Myodaiji, Okazaki, Aichi 444-8787, Japan.,Division of Biophotonics, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Higashiyama 5-1, Myodaiji, Okazaki, Aichi 444-8787, Japan.,School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Higashiyama 5-1, Myodaiji, Okazaki, Aichi 444-8787, Japan.,Research Institute for Electronic Science, Hokkaido University, Hokkaido, Kita 20 Nishi 10, Kita-ku, Sapporo, Hokkaido 001-0020, Japan.,Graduate School of Information Science and Technology Hokkaido University, Hokkaido, Kita 20 Nishi 10, Kita-ku, Sapporo, Hokkaido 001-0020, Japan
| | - Yosuke Okamura
- Department of Applied Chemistry, School of Engineering, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292, Japan.,Micro/Nano Technology Center, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292, Japan.,Course of Applied Science, Graduate School of Engineering, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292, Japan
| | - Tomomi Nemoto
- Biophotonics Research Group, Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Higashiyama 5-1, Myodaiji, Okazaki, Aichi 444-8787, Japan.,Division of Biophotonics, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Higashiyama 5-1, Myodaiji, Okazaki, Aichi 444-8787, Japan.,School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Higashiyama 5-1, Myodaiji, Okazaki, Aichi 444-8787, Japan.,Research Institute for Electronic Science, Hokkaido University, Hokkaido, Kita 20 Nishi 10, Kita-ku, Sapporo, Hokkaido 001-0020, Japan.,Graduate School of Information Science and Technology Hokkaido University, Hokkaido, Kita 20 Nishi 10, Kita-ku, Sapporo, Hokkaido 001-0020, Japan
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Xiong J, Wang W, Wang C, Zhong C, Ruan R, Mao Z, Liu Z. Visualizing Peroxynitrite in Microvessels of the Brain with Stroke Using an Engineered Highly Specific Fluorescent Probe. ACS Sens 2020; 5:3237-3245. [PMID: 33092345 DOI: 10.1021/acssensors.0c01555] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Stroke is one of the leading causes of death and disability in the world, which is associated with malfunction of reactive oxygen species and reactive nitrogen species (ROS/RNS) in cerebral microvessels. In vivo monitoring these species, such as ONOO-, with high selectivity in stroke process is of great significance for early diagnoses and therapies of the disease. Herein, by engineering an indoline-2,3-dione moiety as the recognizing domain, we proposed a novel fluorescence probe Rd-PN2 with highly specific response toward ONOO-, even in the coexistence of other ROS/RNS with high concentration. Rd-PN2 showed high sensitivity and reaction speed in response to ONOO- and exhibited satisfying performances in tracking the endogenously generated ONOO- in living cells and zebrafish. Accordingly, Rd-PN2 can furnish real-time and in vivo visualizing of ONOO- in cerebral microvessels of mice with ischemic and hemorrhagic strokes under two-photon microscopy. This work presented a precisely modulated fluorescence probe for real-time visualizing of ONOO- production in cerebral micovessels, which will also help to acquire more accurate information in the studies of ONOO- functions in the future.
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Affiliation(s)
- Jianhua Xiong
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials & Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, China
| | - Weiwei Wang
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials & Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, China
| | - Caixia Wang
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials & Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, China
| | - Cheng Zhong
- Hubei Key Laboratory on Organic and Polymeric Optoelectronic Materials, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, Hubei 430072, China
| | - Renqiang Ruan
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials & Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, China
| | - Zhiqiang Mao
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials & Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, China
| | - Zhihong Liu
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials & Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, China
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133
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Echagarruga CT, Gheres KW, Norwood JN, Drew PJ. nNOS-expressing interneurons control basal and behaviorally evoked arterial dilation in somatosensory cortex of mice. eLife 2020; 9:e60533. [PMID: 33016877 PMCID: PMC7556878 DOI: 10.7554/elife.60533] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 10/02/2020] [Indexed: 12/19/2022] Open
Abstract
Cortical neural activity is coupled to local arterial diameter and blood flow. However, which neurons control the dynamics of cerebral arteries is not well understood. We dissected the cellular mechanisms controlling the basal diameter and evoked dilation in cortical arteries in awake, head-fixed mice. Locomotion drove robust arterial dilation, increases in gamma band power in the local field potential (LFP), and increases calcium signals in pyramidal and neuronal nitric oxide synthase (nNOS)-expressing neurons. Chemogenetic or pharmocological modulation of overall neural activity up or down caused corresponding increases or decreases in basal arterial diameter. Modulation of pyramidal neuron activity alone had little effect on basal or evoked arterial dilation, despite pronounced changes in the LFP. Modulation of the activity of nNOS-expressing neurons drove changes in the basal and evoked arterial diameter without corresponding changes in population neural activity.
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Affiliation(s)
| | - Kyle W Gheres
- Molecular, Cellular, and Integrative Biology Graduate Program, Pennsylvania State UniversityUniversity ParkUnited States
| | - Jordan N Norwood
- Cell and Developmental Biology Graduate Program, Pennsylvania State UniversityUniversity ParkUnited States
| | - Patrick J Drew
- Bioengineering Graduate Program, Pennsylvania State UniversityUniversity ParkUnited States
- Molecular, Cellular, and Integrative Biology Graduate Program, Pennsylvania State UniversityUniversity ParkUnited States
- Cell and Developmental Biology Graduate Program, Pennsylvania State UniversityUniversity ParkUnited States
- Departments of Engineering Science and Mechanics, Biomedical Engineering, and Neurosurgery, Pennsylvania State UniversityUniversity ParkUnited States
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134
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He Y, Wang M, Yu X. High spatiotemporal vessel-specific hemodynamic mapping with multi-echo single-vessel fMRI. J Cereb Blood Flow Metab 2020; 40:2098-2114. [PMID: 31696765 PMCID: PMC7786852 DOI: 10.1177/0271678x19886240] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
High-resolution fMRI enables noninvasive mapping of the hemodynamic responses from individual penetrating vessels in animal brains. Here, a 2D multi-echo single-vessel fMRI (MESV-fMRI) method has been developed to map the fMRI signal from arterioles and venules with a 100 ms sampling rate at multiple echo times (TE, 3-30 ms) and short acquisition windows (<1 ms). The T2*-weighted signal shows the increased extravascular effect on venule voxels as a function of TE. In contrast, the arteriole voxels show an increased fMRI signal with earlier onset than venules voxels at the short TE (3 ms) with increased blood inflow and volume effects. MESV-fMRI enables vessel-specific T2* mapping and presents T2*-based fMRI time courses with higher contrast-to-noise ratios (CNRs) than the T2*-weighted fMRI signal at a given TE. The vessel-specific T2* mapping also allows semi-quantitative estimation of the oxygen saturation levels (Y) and their changes (ΔY) at a given blood volume fraction upon neuronal activation. The MESV-fMRI method enables vessel-specific T2* measurements with high spatiotemporal resolution for better modeling of the fMRI signal based on the hemodynamic parameters.
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Affiliation(s)
- Yi He
- Translational Neuroimaging and Neural Control Group, High Field Magnetic Resonance Department, Max Planck Institute for Biological Cybernetics, Tuebingen, Germany.,Graduate Training Centre of Neuroscience, International Max Planck Research School, University of Tuebingen, Tuebingen, Germany.,Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
| | - Maosen Wang
- Translational Neuroimaging and Neural Control Group, High Field Magnetic Resonance Department, Max Planck Institute for Biological Cybernetics, Tuebingen, Germany.,Graduate Training Centre of Neuroscience, International Max Planck Research School, University of Tuebingen, Tuebingen, Germany
| | - Xin Yu
- Translational Neuroimaging and Neural Control Group, High Field Magnetic Resonance Department, Max Planck Institute for Biological Cybernetics, Tuebingen, Germany.,Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
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135
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Li R, Ng TS, Garlin MA, Weissleder R, Miller MA. Understanding the in vivo Fate of Advanced Materials by Imaging. ADVANCED FUNCTIONAL MATERIALS 2020; 30:1910369. [PMID: 38545084 PMCID: PMC10972611 DOI: 10.1002/adfm.201910369] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 02/09/2020] [Indexed: 11/13/2024]
Abstract
Engineered materials are ubiquitous in biomedical applications ranging from systemic drug delivery systems to orthopedic implants, and their actions unfold across multiple time- and length-scales. The efficacy and safety of biologics, nanomaterials, and macroscopic implants are all dictated by the same general principles of pharmacology as apply to small molecule drugs, comprising how the body affects materials (pharmacokinetics, PK) and conversely how materials affect the body (pharmacodynamics, PD). Imaging technologies play an increasingly insightful role in monitoring both of these processes, often simultaneously: translational macroscopic imaging modalities such as MRI and PET/CT offer whole-body quantitation of biodistribution and structural or molecular response, while ex vivo approaches and optical imaging via in vivo (intravital) microscopy reveal behaviors at subcellular resolution. In this review, the authors survey developments in imaging the in situ behavior of systemically and locally administered materials, with a particular focus on using microscopy to understand transport, target engagement, and downstream host responses at a single-cell level. The themes of microenvironmental influence, controlled drug release, on-target molecular action, and immune response, especially as mediated by macrophages and other myeloid cells are examined. Finally, the future directions of how new imaging technologies may propel efficient clinical translation of next-generation therapeutics and medical devices are proposed.
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Affiliation(s)
- Ran Li
- Center for Systems Biology, Massachusetts General Hospital Research Institute
| | - Thomas S.C. Ng
- Center for Systems Biology, Massachusetts General Hospital Research Institute
| | - Michelle A. Garlin
- Center for Systems Biology, Massachusetts General Hospital Research Institute
| | - Ralph Weissleder
- Center for Systems Biology, Massachusetts General Hospital Research Institute
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School
- Department of Systems Biology, Harvard Medical School
| | - Miles A. Miller
- Center for Systems Biology, Massachusetts General Hospital Research Institute
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School
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136
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Medin aggregation causes cerebrovascular dysfunction in aging wild-type mice. Proc Natl Acad Sci U S A 2020; 117:23925-23931. [PMID: 32900929 DOI: 10.1073/pnas.2011133117] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Medin is the most common amyloid known in humans, as it can be found in blood vessels of the upper body in virtually everybody over 50 years of age. However, it remains unknown whether deposition of Medin plays a causal role in age-related vascular dysfunction. We now report that aggregates of Medin also develop in the aorta and brain vasculature of wild-type mice in an age-dependent manner. Strikingly, genetic deficiency of the Medin precursor protein, MFG-E8, eliminates not only vascular aggregates but also prevents age-associated decline of cerebrovascular function in mice. Given the prevalence of Medin aggregates in the general population and its role in vascular dysfunction with aging, targeting Medin may become a novel approach to sustain healthy aging.
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137
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Regeneration of the neurogliovascular unit visualized in vivo by transcranial live-cell imaging. J Neurosci Methods 2020; 343:108808. [DOI: 10.1016/j.jneumeth.2020.108808] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 06/02/2020] [Accepted: 06/11/2020] [Indexed: 12/15/2022]
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138
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Kedarasetti RT, Turner KL, Echagarruga C, Gluckman BJ, Drew PJ, Costanzo F. Functional hyperemia drives fluid exchange in the paravascular space. Fluids Barriers CNS 2020; 17:52. [PMID: 32819402 PMCID: PMC7441569 DOI: 10.1186/s12987-020-00214-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 08/09/2020] [Indexed: 12/20/2022] Open
Abstract
The brain lacks a conventional lymphatic system to remove metabolic waste. It has been proposed that directional fluid movement through the arteriolar paravascular space (PVS) promotes metabolite clearance. We performed simulations to examine if arteriolar pulsations and dilations can drive directional CSF flow in the PVS and found that arteriolar wall movements do not drive directional CSF flow. We propose an alternative method of metabolite clearance from the PVS, namely fluid exchange between the PVS and the subarachnoid space (SAS). In simulations with compliant brain tissue, arteriolar pulsations did not drive appreciable fluid exchange between the PVS and the SAS. However, when the arteriole dilated, as seen during functional hyperemia, there was a marked exchange of fluid. Simulations suggest that functional hyperemia may serve to increase metabolite clearance from the PVS. We measured blood vessels and brain tissue displacement simultaneously in awake, head-fixed mice using two-photon microscopy. These measurements showed that brain deforms in response to pressure changes in PVS, consistent with our simulations. Our results show that the deformability of the brain tissue needs to be accounted for when studying fluid flow and metabolite transport.
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Affiliation(s)
- Ravi Teja Kedarasetti
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, USA
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, USA
| | - Kevin L Turner
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, USA
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Christina Echagarruga
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, USA
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Bruce J Gluckman
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, USA
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, USA
- Department of Neurosurgery, The Pennsylvania State University, University Park, PA, USA
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Patrick J Drew
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, USA.
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, USA.
- Department of Neurosurgery, The Pennsylvania State University, University Park, PA, USA.
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA.
| | - Francesco Costanzo
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, USA.
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, USA.
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA.
- Department of Mathematics, The Pennsylvania State University, University Park, PA, USA.
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139
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Non-invasive in-vivo 3-D imaging of small animals using spatially filtered enhanced truncated-correlation photothermal coherence tomography. Sci Rep 2020; 10:13743. [PMID: 32792647 PMCID: PMC7426848 DOI: 10.1038/s41598-020-70815-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 06/30/2020] [Indexed: 11/08/2022] Open
Abstract
We present enhanced truncated-correlation phototothermal coherence tomography (eTC-PCT) for non-invasive three-dimensional imaging of small animals. Tumor detection is reported in a mouse thigh by injecting cancerous cells in the thigh followed by eTC-PCT imaging. Detection of the tumor 3 days after injection may lead to potential for using the eTC-PCT method for cancer treatment studies. eTC-PCT was also applied successfully to non-invasive in-vivo mouse brain structural imaging. A unique spatial-gradient-gate adaptive filter was introduced in a scanned mode along the (x,y) coordinates of camera images from different sub-cranial depths, revealing absorber true spatial extent from diffusive photothermal images and restoring pre-diffusion lateral image resolution beyond the Rayleigh criterion limit in diffusion-wave imaging science. The spatial resolution and contrast enhancement demonstrated in photothermal in-vivo and ex-vivo images of the mouse brain revealed not only vascular structures but also other brain structures, such as the brain hemispheres, cerebellum, and olfactory lobes.
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140
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Fu X, Sompol P, Brandon JA, Norris CM, Wilkop T, Johnson LA, Richards CI. In Vivo Single-Molecule Detection of Nanoparticles for Multiphoton Fluorescence Correlation Spectroscopy to Quantify Cerebral Blood Flow. NANO LETTERS 2020; 20:6135-6141. [PMID: 32628854 PMCID: PMC8405275 DOI: 10.1021/acs.nanolett.0c02280] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We present the application of multiphoton in vivo fluorescence correlation spectroscopy (FCS) of fluorescent nanoparticles for the measurement of cerebral blood flow with excellent spatial and temporal resolution. Through the detection of single nanoparticles within the complex vessel architecture of a live mouse, this new approach enables the quantification of nanoparticle dynamics occurring within the vasculature along with simultaneous measurements of blood flow properties in the brain. In addition to providing high resolution blood flow measurements, this approach enables real-time quantification of nanoparticle concentration, degradation, and transport. This method is capable of quantifying flow rates at each pixel with submicron resolution to enable monitoring of dynamic changes in flow rates in response to changes in the animal's physiological condition. Scanning the excitation beam using FCS provides pixel by pixel mapping of flow rates with subvessel resolution across capillaries 300 μm deep in the brains of mice.
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Affiliation(s)
- Xu Fu
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Pradoldej Sompol
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky 40536, United States
| | - Jason A Brandon
- Department of Physiology, University of Kentucky, Lexington, Kentucky 40536, United States
| | - Christopher M Norris
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky 40536, United States
| | - Thomas Wilkop
- Light Microscopy Core, University of Kentucky, Lexington, Kentucky 40536, United States
| | - Lance A Johnson
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky 40536, United States
- Department of Physiology, University of Kentucky, Lexington, Kentucky 40536, United States
| | - Christopher I Richards
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
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141
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Wang Y, Liang G, Liu F, Chen Q, Xi L. A Long-Term Cranial Window for High-Resolution Photoacoustic Imaging. IEEE Trans Biomed Eng 2020; 68:706-711. [PMID: 32746074 DOI: 10.1109/tbme.2020.3012663] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE In this study, we introduce the design, fabrication, and assessment of an optically and acoustically transparent, long-term and biocompatible cranial window for high-resolution photoacoustic microscopy of rat cerebral cortex. METHODS The cranial window is fabricated with a polydimethylsiloxane (PDMS) layer bonded with a glass ring (outer diameter: 8 mm, inner diameter: 5 mm) via air plasma cleaning. A detailed comparison of image quality was performed with the implantation of cranial windows using different thicknesses of the PDMS film, and the cover glass. In addition, long-term in vivo monitoring of rat cerebral cortex was conducted to evaluate the stability of the cranial window. Furthermore, we successfully applied this window for longitudinal photoacoustic imaging in freely moving rats. RESULTS Based on a detailed evaluation, the cranial window fabricated with PDMS has a better imaging quality compared with a conventional cover-glass-based cranial window. The optimal film thickness is 50 μm considering the elastic deforming capability of PDMS. The cranial window maintained good quality for 21 and 12 days in anesthetized and free moving rats, respectively. CONCLUSION The cranial window has a good imaging quality for both anesthetized and behaving rats, enabling long-term, high-resolution, and steady photoacoustic imaging of cerebral vasculatures. SIGNIFICANCE Based on the studies of both anesthetized and behaving rats, the proposed cranial window has the potential to be used in the longitudinal in vivo study of chronic brain diseases in freely moving rodents.
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142
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Portörő I, Mukli P, Kocsis L, Hermán P, Caccia D, Perrella M, Mozzarelli A, Ronda L, Mathe D, Eke A. Model-based evaluation of the microhemodynamic effects of PEGylated HBOC molecules in the rat brain cortex: a laser speckle imaging study. BIOMEDICAL OPTICS EXPRESS 2020; 11:4150-4175. [PMID: 32923034 PMCID: PMC7449705 DOI: 10.1364/boe.388089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 04/24/2020] [Accepted: 05/04/2020] [Indexed: 06/11/2023]
Abstract
Hemoglobin-based oxygen carriers (HBOCs) were developed with the aim of substituting transfusions in emergency events. However, they exhibit adverse events, such as nitric oxide (NO) scavenging, vasoactivity, enhanced platelet aggregation, presently hampering their clinical application. The impact of two prototypical PEGylated HBOCs, Euro-PEG-Hb and PEG-HbO2, endowed by different oxygen affinities and hydrodynamic volumes, was assessed on the cerebrocortical parenchymal microhemodynamics, and extravasation through the blood-brain-barrier (BBB) by laser speckle contrast imaging (LSCI) method and near-infrared (NIR) imaging, respectively. By evaluating voxel-wise cerebrocortical red blood cell velocity, non-invasively for its mean kernel-wise value ( v ¯ RBC ), and model-derived kernel-wise predictions for microregional tissue hematocrit, THt, and fractional change in hematocrit-corrected vascular resistance, R', as measures of potential adverse effects (enhanced platelet aggregation and vasoactivity, respectively) we found i) no significant difference between tested HBOCs in the systemic and microregional parameters, and in the relative spatial dispersion of THt, and R' as additional measures of HBOC-related adverse effects, and ii) no extravasation through BBB by Euro-PEG-Hb. We conclude that Euro-PEG-Hb does not exhibit adverse effects in the brain microcirculation that could be directly attributed to NO scavenging.
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Affiliation(s)
- István Portörő
- Institute of Translational Medicine, Semmelweis University, Hungary
- These authors contributed equally to this work
| | - Péter Mukli
- Institute of Translational Medicine, Semmelweis University, Hungary
- Department of Physiology, Semmelweis University, Hungary
- These authors contributed equally to this work
| | - László Kocsis
- Institute of Translational Medicine, Semmelweis University, Hungary
| | - Péter Hermán
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT 06520, USA
| | - Dario Caccia
- Department of Biomedical Science and Technology, University of Milan, Italy
- Department of Food and Drug, University of Parma, Italy
| | - Michele Perrella
- Department of Biomedical Science and Technology, University of Milan, Italy
| | - Andrea Mozzarelli
- Department of Food and Drug, University of Parma, Italy
- Institute of Biophysics, National Research Council, Pisa, Italy
- Biopharmanet-TEC, University of Parma, Italy
| | - Luca Ronda
- Institute of Biophysics, National Research Council, Pisa, Italy
- Biopharmanet-TEC, University of Parma, Italy
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Domokos Mathe
- CROmed Research and Service Centers Ltd., Budapest, Hungary
| | - Andras Eke
- Institute of Translational Medicine, Semmelweis University, Hungary
- Department of Physiology, Semmelweis University, Hungary
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143
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Kedarasetti RT, Drew PJ, Costanzo F. Arterial pulsations drive oscillatory flow of CSF but not directional pumping. Sci Rep 2020; 10:10102. [PMID: 32572120 PMCID: PMC7308311 DOI: 10.1038/s41598-020-66887-w] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 05/28/2020] [Indexed: 01/05/2023] Open
Abstract
The brain lacks a traditional lymphatic system for metabolite clearance. The existence of a "glymphatic system" where metabolites are removed from the brain's extracellular space by convective exchange between interstitial fluid (ISF) and cerebrospinal fluid (CSF) along the paravascular spaces (PVS) around cerebral blood vessels has been controversial. While recent work has shown clear evidence of directional flow of CSF in the PVS in anesthetized mice, the driving force for the observed fluid flow remains elusive. The heartbeat-driven peristaltic pulsation of arteries has been proposed as a probable driver of directed CSF flow. In this study, we use rigorous fluid dynamic simulations to provide a physical interpretation for peristaltic pumping of fluids. Our simulations match the experimental results and show that arterial pulsations only drive oscillatory motion of CSF in the PVS. The observed directional CSF flow can be explained by naturally occurring and/or experimenter-generated pressure differences.
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Affiliation(s)
- Ravi Teja Kedarasetti
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, United States
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, United States
| | - Patrick J Drew
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, United States
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, United States
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, United States
- Department of Neurosurgery, The Pennsylvania State University, University Park, PA, United States
| | - Francesco Costanzo
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, United States.
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, United States.
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, United States.
- Department of Mathematics, The Pennsylvania State University, University Park, PA, United States.
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144
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Park SY, Matte A, Jung Y, Ryu J, Anand WB, Han EY, Liu M, Carbone C, Melisi D, Nagasawa T, Locascio JJ, Lin CP, Silberstein LE, De Franceschi L. Pathologic angiogenesis in the bone marrow of humanized sickle cell mice is reversed by blood transfusion. Blood 2020; 135:2071-2084. [PMID: 31990287 PMCID: PMC7273832 DOI: 10.1182/blood.2019002227] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 01/18/2020] [Indexed: 12/27/2022] Open
Abstract
Sickle cell disease (SCD) is a monogenic red blood cell (RBC) disorder with high morbidity and mortality. Here, we report, for the first time, the impact of SCD on the bone marrow (BM) vascular niche, which is critical for hematopoiesis. In SCD mice, we find a disorganized and structurally abnormal BM vascular network of increased numbers of highly tortuous arterioles occupying the majority of the BM cavity, as well as fragmented sinusoidal vessels filled with aggregates of erythroid and myeloid cells. By in vivo imaging, sickle and control RBCs have significantly slow intravascular flow speeds in sickle cell BM but not in control BM. In sickle cell BM, we find increased reactive oxygen species production in expanded erythroblast populations and elevated levels of HIF-1α. The SCD BM exudate exhibits increased levels of proangiogenic growth factors and soluble vascular cell adhesion molecule-1. Transplantation of SCD mouse BM cells into wild-type mice recapitulates the SCD vascular phenotype. Our data provide a model of SCD BM, in which slow RBC flow and vaso-occlusions further diminish local oxygen availability in the physiologic hypoxic BM cavity. These events trigger a milieu that is conducive to aberrant vessel growth. The distorted neovascular network is completely reversed by a 6-week blood transfusion regimen targeting hemoglobin S to <30%, highlighting the plasticity of the vascular niche. A better insight into the BM microenvironments in SCD might provide opportunities to optimize approaches toward efficient and long-term hematopoietic engraftment in the context of curative therapies.
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Affiliation(s)
- Shin-Young Park
- Transfusion Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA
| | - Alessandro Matte
- Department of Medicine, University of Verona and Azienda Ospedaliera Universitaria Integrata Verona, Verona, Italy
| | - Yookyung Jung
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science, Seoul, Republic of Korea
- Center for Systems Biology and Wellman Center for Photomedicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA
| | - Jina Ryu
- Transfusion Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA
| | - Wilson Babu Anand
- Department of Medicine, University of Verona and Azienda Ospedaliera Universitaria Integrata Verona, Verona, Italy
| | - Eun-Young Han
- Transfusion Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA
| | - Min Liu
- Transfusion Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA
| | - Carmine Carbone
- Department of Medicine, University of Verona and Azienda Ospedaliera Universitaria Integrata Verona, Verona, Italy
| | - Davide Melisi
- Department of Medicine, University of Verona and Azienda Ospedaliera Universitaria Integrata Verona, Verona, Italy
| | - Takashi Nagasawa
- Laboratory of Stem Cell Biology and Developmental Immunology, Graduate School of Frontier Biosciences and Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Joseph J Locascio
- Massachusetts Alzheimer's Disease Research Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA; and
| | - Charles P Lin
- Center for Systems Biology and Wellman Center for Photomedicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA
| | - Leslie E Silberstein
- Transfusion Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA
- Harvard Stem Cell Institute, Cambridge, MA
| | - Lucia De Franceschi
- Department of Medicine, University of Verona and Azienda Ospedaliera Universitaria Integrata Verona, Verona, Italy
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145
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Sancho M, Welsh DG. K IR channels in the microvasculature: Regulatory properties and the lipid-hemodynamic environment. CURRENT TOPICS IN MEMBRANES 2020; 85:227-259. [PMID: 32402641 DOI: 10.1016/bs.ctm.2020.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Basal tone and perfusion control is set in cerebral arteries by the sensing of pressure and flow, key hemodynamic stimuli. These forces establish a contractile foundation within arterial networks upon which local neurovascular stimuli operate. This fundamental process is intimately tied to arterial VM and the rise in cytosolic [Ca2+] by the graded opening of voltage-operated Ca2+ channels. Arterial VM is in turn controlled by a dynamic interaction among several resident ion channels, KIR being one of particular significance. As the name suggests, KIR displays strong inward rectification, retains a small outward component, potentiated by extracellular K+ and blocked by micromolar Ba2+. Cerebrovascular KIR is unique from other K+ currents as it is present in both smooth muscle and endothelium yet lacking in classical regulatory modulation. Such observations have fostered the view that KIR is nothing more than a background conductance, activated by extracellular K+ and which passively facilitates dilation. Recent work in cell model systems has; however, identified two membrane lipids, phosphatidylinositol 4,5-bisphosphate (PIP2) and cholesterol, that interact with KIR2.x, to stabilize the channel in the preferred open or silent state, respectively. Translating this unique form of regulation, recent studies have demonstrated that specific lipid-protein interactions enable unique KIR populations to sense distinct hemodynamic stimuli and set basal tone. This review summarizes the current knowledge of vascular KIR channels and how the lipid and hemodynamic impact their activity.
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Affiliation(s)
- Maria Sancho
- Robarts Research Institute and the Department of Physiology & Pharmacology, University of Western Ontario, London, ON, Canada
| | - Donald G Welsh
- Robarts Research Institute and the Department of Physiology & Pharmacology, University of Western Ontario, London, ON, Canada.
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146
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Liu H, Chen X, Deng X, Zhuang Z, Tong S, Xie W, Li J, Qiu P, Wang K. In vivo deep-brain blood flow speed measurement through third-harmonic generation imaging excited at the 1700-nm window. BIOMEDICAL OPTICS EXPRESS 2020; 11:2738-2744. [PMID: 32499956 PMCID: PMC7249836 DOI: 10.1364/boe.389662] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 03/14/2020] [Accepted: 04/15/2020] [Indexed: 05/28/2023]
Abstract
Measurement of the hemodynamic physical parameter blood flow speed in the brain in vivo is key to understanding brain physiology and pathology. 2-photon fluorescence microscopy with single blood vessel resolution is typically used, which necessitates injection of toxic fluorescent dyes. Here we demonstrate a label-free nonlinear optical technique, third-harmonic generation microscopy excited at the 1700-nm window, that is promising for such measurement. Using a simple femtosecond laser system based on soliton self-frequency shift, we can measure blood flow speed through the whole cortical grey matter, even down to the white matter layer. Together with 3-photon fluorescence microscopy, we further demonstrate that the blood vessel walls generate strong THG signals, and that plasma and circulating blood cells are mutually exclusive in space. This technique can be readily applied to brain research.
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Affiliation(s)
- Hongji Liu
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Xinlin Chen
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Xiangquan Deng
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Ziwei Zhuang
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Shen Tong
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Weixin Xie
- College of Electronics and information engineering, Shenzhen University, Shenzhen, 518060, China
| | - Jia Li
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Ping Qiu
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Ke Wang
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China
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147
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He XF, Zeng YX, Li G, Feng YK, Wu C, Liang FY, Zhang Y, Lan Y, Xu GQ, Pei Z. Extracellular ASC exacerbated the recurrent ischemic stroke in an NLRP3-dependent manner. J Cereb Blood Flow Metab 2020; 40:1048-1060. [PMID: 31216943 PMCID: PMC7181081 DOI: 10.1177/0271678x19856226] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Using a photothrombotic mouse model of single stroke, we show that a single stroke onset increases the nuclear factor-κB (NF-κB), NLR family CARD domain containing protein 4 (NLRC4), and absent in melanoma 2 (AIM2) inflammasomes, as well as the mRNA levels of NLRP3. Next, using a photothrombotic mouse model of recurrent stroke, we found that recurrent strokes increased the activation of NLRP3, exacerbated the brain damage and the pro-inflammatory response in wild type (WT) mice, but not in NLRP3 knockout (NLRP3 KO) mice. Additionally, we found that apoptosis-associated speck-like protein containing a CARD (ASC) protein level surrounding the infarct area was comparatively increased, but that ASC specks outside of microglia in both the ipsilateral and contralateral of stroke site were decreased in NLRP3 KO mice relative to wild-type (WT) controls, and the number of ASC specks surrounding the second infarct area was positively correlated to the damage scores. Mechanistically, we found that recombinant ASC (RecASC) activated NLRP3 and induced pro-inflammatory responses, exacerbating the outcome of ischemic stroke, in WT mice, but not in NLRP3 KO mice. We therefore conclude that the NLRP3 inflammasome is activated by two attacks of stroke, which act together with ASC to exacerbate recurrent strokes.
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Affiliation(s)
- Xiao-Fei He
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yi-Xuan Zeng
- Department of Neurology, Shenzhen 2nd People's Hospital, The First Affiliated Hospital of Shenzhen University, Health Science Center, Shenzhen, Guangdong, China
| | - Ge Li
- Guangdong Provincial Key Labortory of Labortory Animals, Guangdong Laboratory Animals Monitoring Institute, Guangzhou, China
| | - Yu-Kun Feng
- Department of Neurology, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China
| | - Cheng Wu
- Department of Rehabilitation Medicine, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, China
| | - Feng-Yin Liang
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yu Zhang
- Guangdong Provincial Key Labortory of Labortory Animals, Guangdong Laboratory Animals Monitoring Institute, Guangzhou, China
| | - Yue Lan
- Department of Rehabilitation Medicine, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, China.,Department of Rehabilitation Medicine, The Second Affiliated Hospital of South China University of Technology, Guangzhou, China
| | - Guang-Qing Xu
- Department of Rehabilitation Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,China National Clinical Research Center for Neurological Diseases, Beijing, China
| | - Zhong Pei
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
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148
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Ma J, Ma Y, Shuaib A, Winship IR. Impaired Collateral Flow in Pial Arterioles of Aged Rats During Ischemic Stroke. Transl Stroke Res 2020; 11:243-253. [PMID: 31203565 PMCID: PMC7067739 DOI: 10.1007/s12975-019-00710-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 05/02/2019] [Accepted: 06/05/2019] [Indexed: 02/05/2023]
Abstract
Cerebral collateral circulation and age are critical factors in determining outcome from acute ischemic stroke. Aging may lead to rarefaction of cerebral collaterals, and thereby accelerate ischemic injury by reducing penumbral blood flow. Dynamic changes in pial collaterals after onset of cerebral ischemia may vary with age but have not been extensively studied. Here, laser speckle contrast imaging (LSCI) and two-photon laser scanning microscopy (TPLSM) were combined to monitor cerebral pial collaterals between the anterior cerebral artery (ACA) and the middle cerebral artery (MCA) in young adult and aged male Sprague Dawley rats during distal middle cerebral artery occlusion (dMCAo). Histological analysis showed that aged rats had significantly greater volumes of ischemic damage than young rats. LSCI showed that cerebral collateral perfusion declined over time after stroke in aged and young rats, and that this decline was significantly greater in aged rats. TPLSM demonstrated that pial arterioles narrowed faster after dMCAo in aged rats compared to young adult rats. Notably, while arteriole vessel narrowing was comparable 4.5 h after ischemic onset in aged and young adult rats, red blood cell velocity was stable in young adults but declined over time in aged rats. Overall, red blood cell flux through pial arterioles was significantly reduced at all time-points after 90 min post-dMCAo in aged rats relative to young adult rats. Thus, collateral failure is more severe in aged rats with significantly impaired pial collateral dynamics (reduced diameter, red blood cell velocity, and red blood cell flux) relative to young adult rats.
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Affiliation(s)
- Junqiang Ma
- Neurochemical Research Unit, Department of Psychiatry, Faculty of Medicine and Dentistry, University of Alberta, 12-127 Clinical Sciences Building, Edmonton, AB, T6G 2R3, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
- First Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong, China
| | - Yonglie Ma
- Neurochemical Research Unit, Department of Psychiatry, Faculty of Medicine and Dentistry, University of Alberta, 12-127 Clinical Sciences Building, Edmonton, AB, T6G 2R3, Canada
| | - Ashfaq Shuaib
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
- Division of Neurology, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Ian R Winship
- Neurochemical Research Unit, Department of Psychiatry, Faculty of Medicine and Dentistry, University of Alberta, 12-127 Clinical Sciences Building, Edmonton, AB, T6G 2R3, Canada.
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada.
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149
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Bardet SM, Cortese J, Blanc R, Mounayer C, Rouchaud A. Multiphoton microscopy for pre-clinical evaluation of flow-diverter stents for treating aneurysms. J Neuroradiol 2020; 48:200-206. [PMID: 32205257 DOI: 10.1016/j.neurad.2020.03.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 03/09/2020] [Accepted: 03/10/2020] [Indexed: 12/17/2022]
Abstract
BACKGROUND Conventional histological analyses are the gold standard for the study of aneurysms and vascular pathologies in pre-clinical research. Over the past decade, in vivo and ex vivo imaging using multiphoton microscopy have emerged as powerful pre-clinical tools for detailed tissue analyses that can assess morphology, the extracellular matrix (ECM), cell density and vascularisation. Multiphoton microscopy allows for deeper tissue penetration with minor phototoxicity. OBJECTIVE The present study aimed to demonstrate the current status of multimodality imaging, including multiphoton microscopy, for detailed analyses of neo-endothelialisation and ECM evolution after flow-diverter stent (FDS) treatment in an experimental rabbit model of aneurysms. METHODS Multiphoton microscopy tools for assessing autofluorescence and second harmonic generation (SHG) signals from biological tissues were used to evaluate the endovascular treatment of intracranial aneurysms in an animal model of aneurysms (pig, rabbit). Results from multiphoton microscopy were compared to those from standard histology, electronic and bright field microscopy. CONCLUSIONS The present study describes novel evaluation modes based on multiphoton microscopy for visualising tissue morphology (e.g., collagen, elastin, and cells) to qualify and quantify the extent of neo-intimal formation of covered arteries and device integration into the arterial wall using a rabbit model of intracranial aneurysms treated with FDS.
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Affiliation(s)
- Sylvia M Bardet
- University of Limoges, 123, avenue Albert-Thomas, XLIM UMR CNRS 7252, 87060 Limoges, France.
| | - Jonathan Cortese
- Bichat University Hospital, INSERM U1148-LVTS, Paris, France; Bicetre Hospital, Department of Interventional Neuroradiology, Paris, France
| | - Raphaël Blanc
- Department of Interventional Neuroradiology, Fondation Ophtalmologique Adolphe-de-Rothschild, Paris, France
| | - Charbel Mounayer
- University of Limoges, 123, avenue Albert-Thomas, XLIM UMR CNRS 7252, 87060 Limoges, France; University Hospital, Department of Interventional Neuroradiology, Limoges, France
| | - Aymeric Rouchaud
- University of Limoges, 123, avenue Albert-Thomas, XLIM UMR CNRS 7252, 87060 Limoges, France; University Hospital, Department of Interventional Neuroradiology, Limoges, France.
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150
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Han X, Chai Z, Ping X, Song LJ, Ma C, Ruan Y, Jin X. In vivo Two-Photon Imaging Reveals Acute Cerebral Vascular Spasm and Microthrombosis After Mild Traumatic Brain Injury in Mice. Front Neurosci 2020; 14:210. [PMID: 32210758 PMCID: PMC7077429 DOI: 10.3389/fnins.2020.00210] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Accepted: 02/25/2020] [Indexed: 12/23/2022] Open
Abstract
Mild traumatic brain injury (mTBI), or concussion, is reported to interfere with cerebral blood flow and microcirculation in patients, but our current understanding is quite limited and the results are often controversial. Here we used longitudinal in vivo two-photon imaging to investigate dynamic changes in cerebral vessels and velocities of red blood cells (RBC) following mTBI. Closed-head mTBI induced using a controlled cortical impact device resulted in a significant reduction of dwell time in a Rotarod test but no significant change in water maze test. Cerebral blood vessels were repeatedly imaged through a thinned skull window at baseline, 0.5, 1, 6 h, and 1 day following mTBI. In both arterioles and capillaries, their diameters and RBC velocities were significantly decreased at 0.5, 1, and 6 h after injury, and recovered in 1 day post-mTBI. In contrast, decreases in the diameter and RBC velocity of venules occurred only in 0.5–1 h after mTBI. We also observed formation and clearance of transient microthrombi in capillaries within 1 h post-mTBI. We concluded that in vivo two-photon imaging is useful for studying earlier alteration of vascular dynamics after mTBI and that mTBI induced reduction of cerebral blood flow, vasospasm, and formation of microthrombi in the acute stage following injury. These changes may contribute to early brain functional deficits of mTBI.
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Affiliation(s)
- Xinjia Han
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States.,Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, United States.,Department of Obstetrics and Gynecology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China.,GHM Institute of CNS Regeneration (GHMICR), Jinan University, Guangzhou, China
| | - Zhi Chai
- Neurobiology Research Center, Shanxi Key Laboratory of Innovative Drugs for Serious Illness, College of Basic Medicine, Shaanxi University of Chinese Medicine, Jinzhong, China
| | - Xingjie Ping
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States.,Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Li-Juan Song
- Neurobiology Research Center, Shanxi Key Laboratory of Innovative Drugs for Serious Illness, College of Basic Medicine, Shaanxi University of Chinese Medicine, Jinzhong, China
| | - Cungen Ma
- Neurobiology Research Center, Shanxi Key Laboratory of Innovative Drugs for Serious Illness, College of Basic Medicine, Shaanxi University of Chinese Medicine, Jinzhong, China
| | - Yiwen Ruan
- GHM Institute of CNS Regeneration (GHMICR), Jinan University, Guangzhou, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Xiaoming Jin
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States.,Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, United States
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