151
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Evans TA, Barkauskas DS, Silver J. Intravital imaging of immune cells and their interactions with other cell types in the spinal cord: Experiments with multicolored moving cells. Exp Neurol 2019; 320:112972. [PMID: 31234058 DOI: 10.1016/j.expneurol.2019.112972] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 05/25/2019] [Accepted: 06/04/2019] [Indexed: 12/25/2022]
Abstract
Intravital imaging of the immune system is a powerful technique for studying biology of the immune response in the spinal cord using a variety of disease models ranging from traumatic injury to autoimmune disorders. Here, we will discuss specific technical aspects as well as many intriguing biological phenomena that have been revealed with the use of intravital imaging for investigation of the immune system in the spinal cord. We will discuss surgical techniques for exposing and stabilizing the spine that are critical for obtaining images, visualizing immune and CNS cells with genetically expressed fluorescent proteins, fluorescent labeling techniques and briefly discuss some of the challenges of image analysis.
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Affiliation(s)
- Teresa A Evans
- Department of Pediatrics, Stanford University, Stanford, CA, USA.
| | | | - Jerry Silver
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
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152
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Sancho M, Fabris S, Hald BO, Brett SE, Sandow SL, Poepping TL, Welsh DG. Membrane Lipid-K
IR
2.x Channel Interactions Enable Hemodynamic Sensing in Cerebral Arteries. Arterioscler Thromb Vasc Biol 2019; 39:1072-1087. [DOI: 10.1161/atvbaha.119.312493] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Objective—
Inward rectifying K
+
(K
IR
) channels are present in cerebral arterial smooth muscle and endothelial cells, a tandem arrangement suggestive of a dynamic yet undiscovered role for this channel. This study defined whether distinct pools of cerebral arterial K
IR
channels were uniquely modulated by membrane lipids and hemodynamic stimuli.
Approach and Results—
A Ba
2+
-sensitive K
IR
current was isolated in smooth muscle and endothelial cells of rat cerebral arteries; molecular analyses subsequently confirmed K
IR
2.1/K
IR
2.2 mRNA and protein expression in both cells. Patch-clamp electrophysiology next demonstrated that each population of K
IR
channels was sensitive to key membrane lipids and hemodynamic stimuli. In this regard, endothelial K
IR
was sensitive to phosphatidylinositol 4,5-bisphosphate content, with depletion impairing the ability of laminar shear stress to activate this channel pool. In contrast, smooth muscle K
IR
was sensitive to membrane cholesterol content, with sequestration blocking the ability of pressure to inhibit channel activity. The idea that membrane lipids help confer shear stress and pressure sensitivity of K
IR
channels was confirmed in intact arteries using myography. Virtual models integrating structural/electrical observations reconceptualized K
IR
as a dynamic regulator of membrane potential working in concert with other currents to set basal tone across a range of shear stresses and intravascular pressures.
Conclusions—
The data show for the first time that specific membrane lipid-K
IR
interactions enable unique channel populations to sense hemodynamic stimuli and drive vasomotor responses to set basal perfusion in the cerebral circulation.
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Affiliation(s)
- Maria Sancho
- From the Department of Physiology and Pharmacology, Robarts Research Institute (M.S., S.F., S.E.B., D.G.W.), University of Western Ontario, London, Canada
| | - Sergio Fabris
- From the Department of Physiology and Pharmacology, Robarts Research Institute (M.S., S.F., S.E.B., D.G.W.), University of Western Ontario, London, Canada
| | - Bjorn O. Hald
- Department of Neuroscience, Translational Neurobiology, University of Copenhagen, Denmark (B.O.H.)
| | - Suzanne E. Brett
- From the Department of Physiology and Pharmacology, Robarts Research Institute (M.S., S.F., S.E.B., D.G.W.), University of Western Ontario, London, Canada
| | - Shaun L. Sandow
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Queensland, Australia (S.L.S.)
| | - Tamie L. Poepping
- Department of Physics and Astronomy (T.L.P.), University of Western Ontario, London, Canada
| | - Donald G. Welsh
- From the Department of Physiology and Pharmacology, Robarts Research Institute (M.S., S.F., S.E.B., D.G.W.), University of Western Ontario, London, Canada
- Department of Physiology and Pharmacology, University of Calgary, Alberta, Canada (D.G.W.)
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153
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He J, Lu H, Young L, Deng R, Callow D, Tong S, Jia X. Real-time quantitative monitoring of cerebral blood flow by laser speckle contrast imaging after cardiac arrest with targeted temperature management. J Cereb Blood Flow Metab 2019; 39:1161-1171. [PMID: 29283290 PMCID: PMC6547180 DOI: 10.1177/0271678x17748787] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Brain injury is the main cause of mortality and morbidity after cardiac arrest (CA). Changes in cerebral blood flow (CBF) after reperfusion are associated with brain injury and recovery. To characterize the relative CBF (rCBF) after CA, 14 rats underwent 7 min asphyxia-CA and were randomly treated with 6 h post-resuscitation normothermic (36.5-37.5℃) or hypothermic- (32-34℃) targeted temperature management (TTM) (N = 7). rCBF was monitored by a laser speckle contrast imaging (LSCI) technique. Brain recovery was evaluated by neurologic deficit score (NDS) and quantitative EEG - information quantity (qEEG-IQ). There were regional differences in rCBF among veins of distinct cerebral areas and heterogeneous responses among the three components of the vascular system. Hypothermia immediately following return of spontaneous circulation led to a longer hyperemia duration (19.7 ± 1.8 vs. 12.7 ± 0.8 min, p < 0.01), a lower rCBF (0.73 ± 0.01 vs. 0.79 ± 0.01; p < 0.001) at the hypoperfusion phase, a better NDS (median [25th-75th], 74 [61-77] vs. 49 [40-77], p < 0.01), and a higher qEEG-IQ (0.94 ± 0.02 vs. 0.77 ± 0.02, p < 0.001) compared with normothermic TTM. High resolution LSCI technique demonstrated hypothermic TTM extends hyperemia duration, delays onset of hypoperfusion phase and lowered rCBF, which is associated with early restoration of electrophysiological recovery and improved functional outcome after CA.
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Affiliation(s)
- Junyun He
- 1 Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Hongyang Lu
- 2 School of Biomedical Engineering, Shanghai Jiaotong University, Shanghai, China
| | - Leanne Young
- 1 Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, USA.,3 Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ruoxian Deng
- 1 Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, USA.,3 Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Daniel Callow
- 1 Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Shanbao Tong
- 2 School of Biomedical Engineering, Shanghai Jiaotong University, Shanghai, China
| | - Xiaofeng Jia
- 1 Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, USA.,3 Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,4 Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, USA.,5 Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA.,6 Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
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154
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Joseph A, Guevara-Torres A, Schallek J. Imaging single-cell blood flow in the smallest to largest vessels in the living retina. eLife 2019; 8:45077. [PMID: 31084705 PMCID: PMC6516827 DOI: 10.7554/elife.45077] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 04/15/2019] [Indexed: 01/15/2023] Open
Abstract
Tissue light scatter limits the visualization of the microvascular network deep inside the living mammal. The transparency of the mammalian eye provides a noninvasive view of the microvessels of the retina, a part of the central nervous system. Despite its clarity, imperfections in the optics of the eye blur microscopic retinal capillaries, and single blood cells flowing within. This limits early evaluation of microvascular diseases that originate in capillaries. To break this barrier, we use 15 kHz adaptive optics imaging to noninvasively measure single-cell blood flow, in one of the most widely used research animals: the C57BL/6J mouse. Measured flow ranged four orders of magnitude (0.0002-1.55 µL min-1) across the full spectrum of retinal vessel diameters (3.2-45.8 µm), without requiring surgery or contrast dye. Here, we describe the ultrafast imaging, analysis pipeline and automated measurement of millions of blood cell speeds.
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Affiliation(s)
- Aby Joseph
- Institute of Optics, University of Rochester, New York, United States.,Center for Visual Science, University of Rochester, New York, United States
| | - Andres Guevara-Torres
- Institute of Optics, University of Rochester, New York, United States.,Center for Visual Science, University of Rochester, New York, United States
| | - Jesse Schallek
- Center for Visual Science, University of Rochester, New York, United States.,Flaum Eye Institute, University of Rochester, New York, United States.,Department of Neuroscience, University of Rochester, New York, United States
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155
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In vivo neurovascular response to focused photoactivation of Channelrhodopsin-2. Neuroimage 2019; 192:135-144. [DOI: 10.1016/j.neuroimage.2019.01.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 12/31/2018] [Accepted: 01/14/2019] [Indexed: 01/03/2023] Open
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156
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Wei W, Li Y, Xie Z, Deegan AJ, Wang RK. Spatial and Temporal Heterogeneities of Capillary Hemodynamics and Its Functional Coupling During Neural Activation. IEEE TRANSACTIONS ON MEDICAL IMAGING 2019; 38:1295-1303. [PMID: 30489265 PMCID: PMC6563900 DOI: 10.1109/tmi.2018.2883244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The cerebral vascular system provides a means to meet the constant metabolic needs of neuronal activities in the brain. Within the cerebral capillary bed, the interactions of spatial and temporal hemodynamics play a deterministic role in oxygen diffusion, however, the progression of which remains unclear. Taking the advantages of high-spatiotemporal resolution of optical coherence tomography capillary velocimetry designed with the eigen-decomposition statistical analysis, we investigated intrinsic red blood cell (RBC) velocities and their spatiotemporal adjustment within the capillaries permeating mouse cerebral cortex during electrical stimulation of contralateral hind paw. We found that the mean capillary transit velocity (mCTV) is increased and its temporal fluctuation bandwidth (TFB) is broadened within hind-paw somatosensory cortex. In addition, the degree to which the mCTV is increased negatively correlates with resting state mCTV, and the degree to which the TFB is increased negatively correlates with both the resting state mCTV and the TFB. In order to confirm the changes are due to hemodynamic regulation, we performed angiographic analyses and found that the vessel density remains almost constant, suggesting the observed functional activation does not involve recruitment of reserved capillaries. To further differentiate the contributions of the mCTV and the TFB to the spatiotemporally coupled hemodynamics, changes in the mCTV and TBF of the capillary flow were modeled and investigated through a Monte Carlo simulation. The results suggest that neural activation evokes the spatial transit time homogenization within the capillary bed, which is regulated via both the heterogeneous acceleration of RBC flow and the heterogeneous increase of temporal RBC fluctuation, ensuring sufficient oxygenation during functional hyperemia.
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157
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Dong F, Chilian WM, Yin L. Knowns and unknowns of coronary artery development and anomalies. Int J Cardiol 2019; 281:40-41. [PMID: 30722959 PMCID: PMC6948020 DOI: 10.1016/j.ijcard.2019.01.073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 01/14/2019] [Accepted: 01/18/2019] [Indexed: 10/27/2022]
Affiliation(s)
- Feng Dong
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA
| | - William M Chilian
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Liya Yin
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA.
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158
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Koletar MM, Dorr A, Brown ME, McLaurin J, Stefanovic B. Refinement of a chronic cranial window implant in the rat for longitudinal in vivo two-photon fluorescence microscopy of neurovascular function. Sci Rep 2019; 9:5499. [PMID: 30940849 PMCID: PMC6445076 DOI: 10.1038/s41598-019-41966-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 03/19/2019] [Indexed: 12/13/2022] Open
Abstract
Longitudinal studies using two–photon fluorescence microscopy (TPFM) are critical for facilitating cellular scale imaging of brain morphology and function. Studies have been conducted in the mouse due to their relatively higher transparency and long term patency of a chronic cranial window. Increasing availability of transgenic rat models, and the range of established behavioural paradigms, necessitates development of a chronic preparation for the rat. However, surgical craniotomies in the rat present challenges due to craniotomy closure by wound healing and diminished image quality due to inflammation, restricting most rat TPFM experiments to acute preparations. Long-term patency is enabled by employing sterile surgical technique, minimization of trauma with precise tissue handling during surgery, judicious selection of the size and placement of the craniotomy, diligent monitoring of animal physiology and support throughout the surgery, and modification of the home cage for long-term preservation of cranial implants. Immunohistochemical analysis employing the glial fibrillary acidic protein (GFAP) and ionized calcium-binding adaptor molecule-1 (Iba-1) showed activation and recruitment of astrocytes and microglia/macrophages directly inferior to the cranial window at one week after surgery, with more diffuse response in deeper cortical layers at two weeks, and amelioration around four weeks post craniotomy. TPFM was conducted up to 14 weeks post craniotomy, reaching cortical depths of 400 µm to 600 µm at most time-points. The rate of signal decay with increasing depth and maximum cortical depth attained had greater variation between individual rats at a single time-point than within a rat across time.
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Affiliation(s)
- Margaret M Koletar
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario, M4N 3M5, Canada.
| | - Adrienne Dorr
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario, M4N 3M5, Canada
| | - Mary E Brown
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario, M4N 3M5, Canada
| | - JoAnne McLaurin
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario, M4N 3M5, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A1, Canada
| | - Bojana Stefanovic
- Department of Medical Biophysics, University of Toronto, 610 University Avenue, Toronto, Ontario, M5G 2M9, Canada.,Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario, M4N 3M5, Canada
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159
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Wang H, Yin Y, Gong D, Hong L, Wu G, Jiang Q, Wang C, Blinder P, Long S, Han F, Lu Y. Cathepsin B inhibition ameliorates leukocyte-endothelial adhesion in the BTBR mouse model of autism. CNS Neurosci Ther 2019; 25:476-485. [PMID: 30328295 PMCID: PMC6488924 DOI: 10.1111/cns.13074] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 08/30/2018] [Accepted: 09/17/2018] [Indexed: 01/08/2023] Open
Abstract
AIMS Autism spectrum disorder (ASD) is a wide range of neurodevelopmental disorders involving deficits in social interaction and communication. Unfortunately, autism remains a scientific and clinical challenge owing to the lack of understanding the cellular and molecular mechanisms underlying it. This study aimed to investigate the pathophysiological mechanism underlying leukocyte-endothelial adhesion in autism-related neurovascular inflammation. METHODS Male BTBR T+tf/J mice were used as an autism model. The dynamic pattern of leukocyte-endothelial adhesion in mouse cerebral vessels was detected by two-photon laser scanning microscopy (TPLSM). Using FACS, RT-PCR, and Western blotting, we explored the expression of cell adhesion molecules, the mRNA expression of endothelial chemokine, the protein levels of cathepsin B, and inflammatory mediators. RESULTS We found a significant increase in leukocyte-endothelial adhesion in BTBR mice, accompanied by elevated expression of the adhesion molecule neutrophils CD11b and endothelial ICAM-1. Our data further indicate that elevated neutrophil cathepsin B levels contribute to elevated endothelial chemokine CXCL7 levels in BTBR mice. The pharmacological inhibition of cathepsin B reverses the enhanced leukocyte-endothelial adhesion in the cerebral vessels of autistic mice. CONCLUSION Our results revealed the prominent role of cathepsin B in modulating leukocyte-endothelial adhesion during autism-related neurovascular inflammation and identified a promising novel approach for autism treatment.
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Affiliation(s)
- Huan Wang
- Key Laboratory of Carbohydrate and Lipid Metabolism Research, College of Life Science and TechnologyDalian UniversityDalianChina
- Institute of Pharmacology and Toxicology, College of Pharmaceutical SciencesZhejiang UniversityHangzhouChina
| | - Yi‐Xuan Yin
- Institute of Pharmacology and Toxicology, College of Pharmaceutical SciencesZhejiang UniversityHangzhouChina
- School of MedicineZhejiang University City CollegeHangzhouChina
| | - Dong‐Mei Gong
- Institute of Pharmacology and Toxicology, College of Pharmaceutical SciencesZhejiang UniversityHangzhouChina
- School of MedicineZhejiang University City CollegeHangzhouChina
| | - Ling‐Juan Hong
- Institute of Pharmacology and Toxicology, College of Pharmaceutical SciencesZhejiang UniversityHangzhouChina
| | - Gang Wu
- Institute of Pharmacology and Toxicology, College of Pharmaceutical SciencesZhejiang UniversityHangzhouChina
| | - Quan Jiang
- Institute of Pharmacology and Toxicology, College of Pharmaceutical SciencesZhejiang UniversityHangzhouChina
| | - Cheng‐Kun Wang
- Institute of Pharmacology and Toxicology, College of Pharmaceutical SciencesZhejiang UniversityHangzhouChina
| | - Pablo Blinder
- Department of Neurobiology, George S. Wise Faculty of Life Sciences, Sagol School for NeuroscienceTel‐Aviv UniversityTel AvivIsrael
| | - Sen Long
- Institute of Pharmacology and Toxicology, College of Pharmaceutical SciencesZhejiang UniversityHangzhouChina
- Department of Pharmacy, Hangzhou No.7 People's HospitalMental Health Center Zhejiang University school of MedicineHangzhouChina
| | - Feng Han
- Institute of Pharmacology and Toxicology, College of Pharmaceutical SciencesZhejiang UniversityHangzhouChina
- Key Laboratory of Cardiovascular & Cerebrovascular Medicine, School of PharmacyNanjing Medical UniversityNanjingChina
| | - Ying‐Mei Lu
- School of MedicineZhejiang University City CollegeHangzhouChina
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160
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De Niz M, Nacer A, Frischknecht F. Intravital microscopy: Imaging host-parasite interactions in the brain. Cell Microbiol 2019; 21:e13024. [PMID: 30830993 DOI: 10.1111/cmi.13024] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 02/14/2019] [Accepted: 02/24/2019] [Indexed: 12/31/2022]
Abstract
Intravital fluorescence microscopy (IVM) is a powerful technique for imaging multiple organs, including the brain of living mice and rats. It enables the direct visualisation of cells in situ providing a real-life view of biological processes that in vitro systems cannot. In addition, to the technological advances in microscopy over the last decade, there have been supporting innovations in data storage and analytical packages that enable the visualisation and analysis of large data sets. Here, we review the advantages and limitations of techniques predominantly used for brain IVM, including thinned skull windows, open skull cortical windows, and a miniaturised optical system based on microendoscopic probes that can be inserted into deep tissues. Further, we explore the relevance of these techniques for the field of parasitology. Several protozoan infections are associated with neurological symptoms including Plasmodium spp., Toxoplasma spp., and Trypanosoma spp. IVM has led to crucial findings on these parasite species, which are discussed in detail in this review.
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Affiliation(s)
- Mariana De Niz
- Institute of Cell Biology, University of Bern, Bern, Switzerland.,Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasglow, UK
| | - Adéla Nacer
- Division of Bacteriology, National Institute for Biological Standards and Control, Medicines and Healthcare products Regulatory Agency, EN63QG, Potters Bar, UK
| | - Friedrich Frischknecht
- Parasitology-Centre for Infectious Diseases, University of Heidelberg Medical School, Heidelberg, Germany
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161
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Berthiaume AA, Grant RI, McDowell KP, Underly RG, Hartmann DA, Levy M, Bhat NR, Shih AY. Dynamic Remodeling of Pericytes In Vivo Maintains Capillary Coverage in the Adult Mouse Brain. Cell Rep 2019; 22:8-16. [PMID: 29298435 DOI: 10.1016/j.celrep.2017.12.016] [Citation(s) in RCA: 126] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 11/01/2017] [Accepted: 12/03/2017] [Indexed: 12/16/2022] Open
Abstract
Direct contact and communication between pericytes and endothelial cells is critical for maintenance of cerebrovascular stability and blood-brain barrier function. Capillary pericytes have thin processes that reach hundreds of micrometers along the capillary bed. The processes of adjacent pericytes come in close proximity but do not overlap, yielding a cellular chain with discrete territories occupied by individual pericytes. Little is known about whether this pericyte chain is structurally dynamic in the adult brain. Using in vivo two-photon imaging in adult mouse cortex, we show that while pericyte somata were immobile, the tips of their processes underwent extensions and/or retractions over days. The selective ablation of single pericytes provoked exuberant extension of processes from neighboring pericytes to contact uncovered regions of the endothelium. Uncovered capillary regions had normal barrier function but were dilated until pericyte contact was regained. Pericyte structural plasticity may be critical for cerebrovascular health and warrants detailed investigation.
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Affiliation(s)
- Andrée-Anne Berthiaume
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Roger I Grant
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Konnor P McDowell
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Robert G Underly
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC 29425, USA
| | - David A Hartmann
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Manuel Levy
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Narayan R Bhat
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Andy Y Shih
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC 29425, USA; Center for Biomedical Imaging, Medical University of South Carolina, Charleston, SC 29425, USA.
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162
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Haft-Javaherian M, Fang L, Muse V, Schaffer CB, Nishimura N, Sabuncu MR. Deep convolutional neural networks for segmenting 3D in vivo multiphoton images of vasculature in Alzheimer disease mouse models. PLoS One 2019; 14:e0213539. [PMID: 30865678 PMCID: PMC6415838 DOI: 10.1371/journal.pone.0213539] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 02/22/2019] [Indexed: 11/20/2022] Open
Abstract
The health and function of tissue rely on its vasculature network to provide reliable blood perfusion. Volumetric imaging approaches, such as multiphoton microscopy, are able to generate detailed 3D images of blood vessels that could contribute to our understanding of the role of vascular structure in normal physiology and in disease mechanisms. The segmentation of vessels, a core image analysis problem, is a bottleneck that has prevented the systematic comparison of 3D vascular architecture across experimental populations. We explored the use of convolutional neural networks to segment 3D vessels within volumetric in vivo images acquired by multiphoton microscopy. We evaluated different network architectures and machine learning techniques in the context of this segmentation problem. We show that our optimized convolutional neural network architecture with a customized loss function, which we call DeepVess, yielded a segmentation accuracy that was better than state-of-the-art methods, while also being orders of magnitude faster than the manual annotation. To explore the effects of aging and Alzheimer's disease on capillaries, we applied DeepVess to 3D images of cortical blood vessels in young and old mouse models of Alzheimer's disease and wild type littermates. We found little difference in the distribution of capillary diameter or tortuosity between these groups, but did note a decrease in the number of longer capillary segments (>75μm) in aged animals as compared to young, in both wild type and Alzheimer's disease mouse models.
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Affiliation(s)
- Mohammad Haft-Javaherian
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States of America
| | - Linjing Fang
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States of America
| | - Victorine Muse
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States of America
| | - Chris B. Schaffer
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States of America
| | - Nozomi Nishimura
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States of America
| | - Mert R. Sabuncu
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States of America
- School of Electrical and Computer Engineering, Cornell University, Ithaca, NY, United States of America
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163
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Anzabi M, Angleys H, Aamand R, Ardalan M, Mouridsen K, Rasmussen PM, Sørensen JCH, Plesnila N, Østergaard L, Iversen NK. Capillary flow disturbances after experimental subarachnoid hemorrhage: A contributor to delayed cerebral ischemia? Microcirculation 2019; 26:e12516. [DOI: 10.1111/micc.12516] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 08/21/2018] [Accepted: 11/12/2018] [Indexed: 01/22/2023]
Affiliation(s)
- Maryam Anzabi
- Department of Clinical Medicine; Center of Functionally Integrative Neuroscience (CFIN); Aarhus University; Aarhus Denmark
| | - Hugo Angleys
- Department of Clinical Medicine; Center of Functionally Integrative Neuroscience (CFIN); Aarhus University; Aarhus Denmark
| | - Rasmus Aamand
- Department of Clinical Medicine; Center of Functionally Integrative Neuroscience (CFIN); Aarhus University; Aarhus Denmark
| | - Maryam Ardalan
- Department of Clinical Medicine; Center of Functionally Integrative Neuroscience (CFIN); Aarhus University; Aarhus Denmark
- Department of Clinical Medicine; Translational Neuropsychiatry Unit; Aarhus University; Aarhus Denmark
| | - Kim Mouridsen
- Department of Clinical Medicine; Center of Functionally Integrative Neuroscience (CFIN); Aarhus University; Aarhus Denmark
| | - Peter Mondrup Rasmussen
- Department of Clinical Medicine; Center of Functionally Integrative Neuroscience (CFIN); Aarhus University; Aarhus Denmark
| | | | - Nikolaus Plesnila
- Institute for Stroke and Dementia Research (ISD); University of Munich Medical Center; Munich Germany
| | - Leif Østergaard
- Department of Clinical Medicine; Center of Functionally Integrative Neuroscience (CFIN); Aarhus University; Aarhus Denmark
- Department of Neuroradiology; Aarhus University Hospital; Aarhus Denmark
| | - Nina Kerting Iversen
- Department of Clinical Medicine; Center of Functionally Integrative Neuroscience (CFIN); Aarhus University; Aarhus Denmark
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164
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In vivo imaging for neurovascular disease research. Arch Pharm Res 2019; 42:263-273. [PMID: 30756309 DOI: 10.1007/s12272-019-01128-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 01/29/2019] [Indexed: 01/10/2023]
Abstract
Connections between various cell types in the brain enable cognitive function. The neurovascular unit is a structure composed of different cell types that regulate neurovascular coupling, blood-brain barrier permeability, and other interactions with peripheral systems. The relationship among the components of the neurovascular unit is complex and difficult to study without the use of in vivo neurovascular disease imaging. In this review, we introduce principles and examples of various in vivo optical imaging techniques including laser Doppler flowmetry, laser speckle contrast imaging, intrinsic optical signal imaging, optical coherence tomography, and two-photon microscopy. Furthermore, we introduce recent advances of in vivo imaging and future directions for promoting neurovascular disease research.
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165
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Gandhi R, Tsoumpas C. Preclinical Imaging Biomarkers for Postischaemic Neurovascular Remodelling. CONTRAST MEDIA & MOLECULAR IMAGING 2019; 2019:3128529. [PMID: 30863220 PMCID: PMC6378027 DOI: 10.1155/2019/3128529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 11/22/2018] [Accepted: 12/04/2018] [Indexed: 11/30/2022]
Abstract
In the pursuit of understanding the pathological alterations that underlie ischaemic injuries, such as vascular remodelling and reorganisation, there is a need for recognising the capabilities and limitations of in vivo imaging techniques. Thus, this review presents contemporary published research of imaging modalities that have been implemented to study postischaemic neurovascular changes in small animals. A comparison of the technical aspects of the various imaging tools is included to set the framework for identifying the most appropriate methods to observe postischaemic neurovascular remodelling. A systematic search of the PubMed® and Elsevier's Scopus databases identified studies that were conducted between 2008 and 2018 to explore postischaemic neurovascular remodelling in small animal models. Thirty-five relevant in vivo imaging studies are included, of which most made use of magnetic resonance imaging or positron emission tomography, whilst various optical modalities were also utilised. Notably, there is an increasing trend of using multimodal imaging to exploit the most beneficial properties of each imaging technique to elucidate different aspects of neurovascular remodelling. Nevertheless, there is still scope for further utilising noninvasive imaging tools such as contrast agents or radiotracers, which will have the ability to monitor neurovascular changes particularly during restorative therapy. This will facilitate more successful utility of the clinical imaging techniques in the interpretation of neurovascular reorganisation over time.
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Affiliation(s)
- Richa Gandhi
- Department of Biomedical Imaging Science, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds LS2 9NL, West Yorkshire, UK
| | - Charalampos Tsoumpas
- Department of Biomedical Imaging Science, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds LS2 9NL, West Yorkshire, UK
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166
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Zhang C, Tabatabaei M, Bélanger S, Girouard H, Moeini M, Lu X, Lesage F. Astrocytic endfoot Ca 2+ correlates with parenchymal vessel responses during 4-AP induced epilepsy: An in vivo two-photon lifetime microscopy study. J Cereb Blood Flow Metab 2019; 39:260-271. [PMID: 28792278 PMCID: PMC6365602 DOI: 10.1177/0271678x17725417] [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: 12/28/2022]
Abstract
Neurovascular coupling (NVC) underlying the local increase in blood flow during neural activity forms the basis of functional brain imaging and is altered in epilepsy. Because astrocytic calcium (Ca2+) signaling is involved in NVC, this study investigates the role of this pathway in epilepsy. Here, we exploit 4-AP induced epileptic events to show that absolute Ca2+ concentration in cortical astrocyte endfeet in vivo correlates with the diameter of precapillary arterioles during neural activity. We simultaneously monitored free Ca2+ concentration in astrocytic endfeet with the Ca2+-sensitive indicator OGB-1 and diameter of adjacent arterioles in the somatosensory cortex of adult mice by two-photon fluorescence lifetime measurements following 4-AP injection. Our results reveal that, regardless of the mechanism by which astrocytic endfoot Ca2+ was elevated during epileptic events, increases in Ca2+ associated with vasodilation for each individual ictal event in the focus. In the remote area, increases in Ca2+ correlated with vasoconstriction at the onset of seizure and vasodilation during the later part of the seizure. Furthermore, a slow increase in absolute Ca2+ with time following multiple seizures was observed, which in turn, correlated with a trend of arteriolar constriction both at the epileptic focus and remote areas.
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Affiliation(s)
- Cong Zhang
- 1 Department of Electrical Engineering, École Polytechnique de Montréal, Montreal, Canada.,2 Montreal Heart Institute, Montreal, Quebec, Canada
| | - Maryam Tabatabaei
- 3 Department of Computer Engineering, École Polytechnique de Montréal, Montreal, Canada
| | - Samuel Bélanger
- 1 Department of Electrical Engineering, École Polytechnique de Montréal, Montreal, Canada
| | - Hélène Girouard
- 4 Department of Pharmacology, University of Montreal, Montreal, Canada
| | - Mohammad Moeini
- 1 Department of Electrical Engineering, École Polytechnique de Montréal, Montreal, Canada.,2 Montreal Heart Institute, Montreal, Quebec, Canada
| | - Xuecong Lu
- 1 Department of Electrical Engineering, École Polytechnique de Montréal, Montreal, Canada.,2 Montreal Heart Institute, Montreal, Quebec, Canada
| | - Frédéric Lesage
- 1 Department of Electrical Engineering, École Polytechnique de Montréal, Montreal, Canada.,2 Montreal Heart Institute, Montreal, Quebec, Canada
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167
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Hyacinth HI, Sugihara CL, Spencer TL, Archer DR, Shih AY. Higher prevalence of spontaneous cerebral vasculopathy and cerebral infarcts in a mouse model of sickle cell disease. J Cereb Blood Flow Metab 2019; 39:342-351. [PMID: 28925802 PMCID: PMC6365608 DOI: 10.1177/0271678x17732275] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Stroke is a dramatic complication of sickle cell disease (SCD), which is associated with cerebral vasculopathies including moya moya, intravascular thrombi, cerebral hyperemia, and increased vessel tortuosity. The spontaneous occurrence of these pathologies in the sickle cell mouse model has not been described. Here, we studied Townes humanized sickle cell and age-matched control mice that were 13 months old. We used in vivo two-photon microscopy to assess blood flow dynamics, vascular topology, and evidence of cerebral vasculopathy. Results showed that compared to controls, sickle cell mice had significantly higher red blood cell (RBC) velocity (0.73 mm/s vs. 0.55 mm/s, p = 0.013), capillary vessel diameter (4.84 µM vs. 4.50 µM, p = 0.014), and RBC volume flux (0.015 nL/s vs. 0.010 nL/s, p = 0.021). Also, sickle cell mice had significantly more tortuous capillary vessels ( p < 0.0001) and significantly shorter capillary vessel branches ( p = 0.0065) compared to controls. Sickle cell mice also had significantly higher number of capillary occlusive events (3.4% vs. 1.9%, p < 0.0001) and RBC stalls (3.8% vs. 2.1%, p < 0.0001) in the cerebral capillary bed. In post-mortem immunohistochemical analyses, sickle cell mice had a 2.5-fold higher frequency of cortical microinfarcts compared to control mice. Our results suggest that aged Townes sickle cell mice spontaneously develop SCD-associated cerebral vasculopathy.
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Affiliation(s)
- Hyacinth I Hyacinth
- 1 Department of Pediatrics, Aflac Cancer and Blood Disorder Center of Children's Healthcare of Atlanta and Emory University, Atlanta, GA, USA
| | - Courtney L Sugihara
- 2 Neuroscience and Behavioral Biology Program, Emory University, Atlanta, GA, USA
| | - Thomas L Spencer
- 3 Department of Mechanical Engineering, Georgia Technical Institute, Atlanta, GA, USA
| | - David R Archer
- 1 Department of Pediatrics, Aflac Cancer and Blood Disorder Center of Children's Healthcare of Atlanta and Emory University, Atlanta, GA, USA
| | - Andy Y Shih
- 4 Department of Neurosciences, Medical University of South Carolina, Charleston, SC, USA.,5 Center for Biomedical Imaging, Medical University of South Carolina, Charleston, SC, USA
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168
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Cao R, Zhang C, Mitkin VV, Lankford MF, Li J, Zuo Z, Meyer CH, Goyne CP, Ahlers ST, Stone JR, Hu S. Comprehensive Characterization of Cerebrovascular Dysfunction in Blast Traumatic Brain Injury Using Photoacoustic Microscopy. J Neurotrauma 2019; 36:1526-1534. [PMID: 30501547 DOI: 10.1089/neu.2018.6062] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Blast traumatic brain injury (bTBI) is a leading contributor to combat-related injuries and death. Although substantial emphasis has been placed on blast-induced neuronal and axonal injuries, co-existing dysfunctions in the cerebral vasculature, particularly the microvasculature, remain poorly understood. Here, we studied blast-induced cerebrovascular dysfunctions in a rat model of bTBI (blast overpressure: 187.8 ± 18.3 kPa). Using photoacoustic microscopy (PAM), we quantified changes in cerebral hemodynamics and metabolism-including blood perfusion, oxygenation, flow, oxygen extraction fraction, and the metabolic rate of oxygen-4 h post-injury. Moreover, we assessed the effect of blast exposure on cerebrovascular reactivity (CVR) to vasodilatory stimulation. With vessel segmentation, we extracted these changes at the single-vessel level, revealing their dependence on vessel type (i.e., artery vs. vein) and diameter. We found that bTBI at this pressure level did not induce pronounced baseline changes in cerebrovascular diameter, blood perfusion, oxygenation, flow, oxygen extraction, and metabolism, except for a slight sO2 increase in small veins (<45 μm) and blood flow increase in large veins (≥45 μm). In contrast, this blast exposure almost abolished CVR, including arterial dilation, flow upregulation, and venous sO2 increase. This study is the most comprehensive assessment of cerebrovascular structure and physiology in response to blast exposure to date. The observed impairment in CVR can potentially cause cognitive decline due to the mismatch between cognitive metabolic demands and vessel's ability to dynamically respond to meet the demands. Also, the impaired CVR can lead to increased vulnerability of the brain to metabolic insults, including hypoxia and ischemia.
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Affiliation(s)
- Rui Cao
- 1 Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia
| | - Chenchu Zhang
- 1 Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia
| | - Vladimir V Mitkin
- 2 Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia
| | - Miles F Lankford
- 3 Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, Virginia
| | - Jun Li
- 4 Department of Anesthesiology, University of Virginia, Charlottesville, Virginia
| | - Zhiyi Zuo
- 4 Department of Anesthesiology, University of Virginia, Charlottesville, Virginia
| | - Craig H Meyer
- 1 Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia
| | - Christopher P Goyne
- 2 Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia
| | - Stephen T Ahlers
- 5 Operational and Undersea Medicine Directorate, Naval Medical Research Center, Silver Spring, Maryland
| | - James R Stone
- 3 Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, Virginia
| | - Song Hu
- 1 Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia
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169
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Paquette T, Leblond H, Piché M. Isoflurane anesthesia does not affect spinal cord neurovascular coupling: evidence from decerebrated rats. J Physiol Sci 2019; 69:13-21. [PMID: 29600499 PMCID: PMC10717246 DOI: 10.1007/s12576-018-0607-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 03/22/2018] [Indexed: 01/22/2023]
Abstract
Neurological examination remains the primary clinical investigation in patients with spinal cord injury. However, neuroimaging methods such as functional magnetic resonance imaging (fMRI) are promising tools for following functional changes in the course of injury, disease and rehabilitation. However, the relationship between neuronal activity and blood flow in the spinal cord on which fMRI relies has been largely overlooked. The objective of this study was to examine neurovascular coupling in the spinal cord of decerebrated rats during electrical stimulation of the sciatic nerve with and without isoflurane anesthesia (1.2%). Local field potentials (LFP) and spinal cord blood flow (SCBF) were recorded simultaneously in the lumbosacral enlargement. Isoflurane did not significantly alter LFP (p = 0.53) and SCBF (p = 0.57) amplitude. Accordingly, neurovascular coupling remained comparable with or without isoflurane anesthesia (p = 0.39). These results support the use of isoflurane in rodents to investigate nociceptive functions of the spinal cord using fMRI.
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Affiliation(s)
- Thierry Paquette
- Department of Chiropractic, Université du Québec à Trois-Rivières, 3351 Boul. Des Forges, C.P. 500, Trois-Rivières, QC, Canada, G9A 5H7
- CogNAC Research Group, Université du Québec à Trois-Rivières, 3351 Boul. Des Forges, C.P. 500, Trois-Rivières, QC, Canada, G9A 5H7
- Department of Anatomy, Université du Québec à Trois-Rivières, 3351 Boul. Des Forges, C.P. 500, Trois-Rivières, QC, Canada, G9A 5H7
| | - Hugues Leblond
- CogNAC Research Group, Université du Québec à Trois-Rivières, 3351 Boul. Des Forges, C.P. 500, Trois-Rivières, QC, Canada, G9A 5H7
- Department of Anatomy, Université du Québec à Trois-Rivières, 3351 Boul. Des Forges, C.P. 500, Trois-Rivières, QC, Canada, G9A 5H7
| | - Mathieu Piché
- Department of Chiropractic, Université du Québec à Trois-Rivières, 3351 Boul. Des Forges, C.P. 500, Trois-Rivières, QC, Canada, G9A 5H7.
- CogNAC Research Group, Université du Québec à Trois-Rivières, 3351 Boul. Des Forges, C.P. 500, Trois-Rivières, QC, Canada, G9A 5H7.
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170
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DeStefano JG, Jamieson JJ, Linville RM, Searson PC. Benchmarking in vitro tissue-engineered blood-brain barrier models. Fluids Barriers CNS 2018; 15:32. [PMID: 30514389 PMCID: PMC6280508 DOI: 10.1186/s12987-018-0117-2] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 11/11/2018] [Indexed: 12/13/2022] Open
Abstract
The blood–brain barrier (BBB) plays a key role in regulating transport into and out of the brain. With increasing interest in the role of the BBB in health and disease, there have been significant advances in the development of in vitro models. The value of these models to the research community is critically dependent on recapitulating characteristics of the BBB in humans or animal models. However, benchmarking in vitro models is surprisingly difficult since much of our knowledge of the structure and function of the BBB comes from in vitro studies. Here we describe a set of parameters that we consider a starting point for benchmarking and validation. These parameters are associated with structure (ultrastructure, wall shear stress, geometry), microenvironment (basement membrane and extracellular matrix), barrier function (transendothelial electrical resistance, permeability, efflux transport), cell function (expression of BBB markers, turnover), and co-culture with other cell types (astrocytes and pericytes). In suggesting benchmarks, we rely primarily on imaging or direct measurements in humans and animal models.
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Affiliation(s)
- Jackson G DeStefano
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA.,Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - John J Jamieson
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA.,Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Raleigh M Linville
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA.,Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Peter C Searson
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA. .,Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, USA. .,120 Croft Hall, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD, 21218, USA.
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171
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Watanabe N, Sasaki S, Masamoto K, Hotta H. Vascular Gap Junctions Contribute to Forepaw Stimulation-Induced Vasodilation Differentially in the Pial and Penetrating Arteries in Isoflurane-Anesthetized Rats. Front Mol Neurosci 2018; 11:446. [PMID: 30559647 PMCID: PMC6286957 DOI: 10.3389/fnmol.2018.00446] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 11/19/2018] [Indexed: 12/25/2022] Open
Abstract
Somatosensory stimulation causes dilation of the pial and penetrating arteries and an increase in cerebral blood flow (CBF) in the representative region of the somatosensory cortex. As an underlying mechanism for such stimulation-induced increases in CBF, cerebral artery dilation has been thought to propagate in the vascular endothelium from the parenchyma to the brain surface. Vascular gap junctions may propagate vasodilation. However, the contribution of vascular gap junctions to cerebrovascular regulation induced by somatosensory stimulation is largely unknown. The aim of the present study was to investigate the contribution of vascular gap junctions to the regulation of the pial and penetrating arteries during neuronal activity attributed to somatosensory stimulation. Experiments were performed on male Wistar rats (age: 7-10 weeks) with artificial ventilation under isoflurane anesthesia. For somatosensory stimulation, the left forepaw was electrically stimulated (1.5 mA, 0.5 ms and 10 Hz, for 5 s). The artery in the forelimb area of the right somatosensory cortex was imaged through a cranial window using a two-photon microscope and the diameter was measured. Carbenoxolone (CBX) was intravenously (i.v.) administered, at a dose of 100 mg/kg, to block vascular gap junctions. The forepaw electrical stimulation increased the diameter of the pial and penetrating arteries by 7.0% and 5.0% of the pre-stimulus diameter, respectively, without changing the arterial pressure. After CBX administration, the change in pial artery diameter during forepaw stimulation was attenuated to 3.2%. However, changes in the penetrating artery were not significantly affected. CBF was measured using a laser speckle flowmeter, together with somatosensory-evoked potential (SEP) recorded in the somatosensory cortex. The extent of CBF increase (by 24.1% of the pre-stimulus level) and amplitude of SEP were not affected by CBX administration. The present results suggest that vascular gap junctions, possibly on the endothelium, contribute to pial artery dilation during neuronal activity induced by somatosensory stimulation.
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Affiliation(s)
- Nobuhiro Watanabe
- Department of Autonomic Neuroscience, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Satoshi Sasaki
- Department of Autonomic Neuroscience, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.,Graduate School of Informatics and Engineering, The University of Electro-Communications, Tokyo, Japan
| | - Kazuto Masamoto
- Department of Autonomic Neuroscience, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.,Graduate School of Informatics and Engineering, The University of Electro-Communications, Tokyo, Japan.,Brain Science Inspired Life Support Research Center, The University of Electro-Communications, Tokyo, Japan
| | - Harumi Hotta
- Department of Autonomic Neuroscience, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
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172
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Simulations of blood as a suspension predicts a depth dependent hematocrit in the circulation throughout the cerebral cortex. PLoS Comput Biol 2018; 14:e1006549. [PMID: 30452440 PMCID: PMC6277127 DOI: 10.1371/journal.pcbi.1006549] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 12/03/2018] [Accepted: 10/05/2018] [Indexed: 12/11/2022] Open
Abstract
Recent advances in modeling oxygen supply to cortical brain tissue have begun to elucidate the functional mechanisms of neurovascular coupling. While the principal mechanisms of blood flow regulation after neuronal firing are generally known, mechanistic hemodynamic simulations cannot yet pinpoint the exact spatial and temporal coordination between the network of arteries, arterioles, capillaries and veins for the entire brain. Because of the potential significance of blood flow and oxygen supply simulations for illuminating spatiotemporal regulation inside the cortical microanatomy, there is a need to create mathematical models of the entire cerebral circulation with realistic anatomical detail. Our hypothesis is that an anatomically accurate reconstruction of the cerebrocirculatory architecture will inform about possible regulatory mechanisms of the neurovascular interface. In this article, we introduce large-scale networks of the murine cerebral circulation spanning the Circle of Willis, main cerebral arteries connected to the pial network down to the microcirculation in the capillary bed. Several multiscale models were generated from state-of-the-art neuroimaging data. Using a vascular network construction algorithm, the entire circulation of the middle cerebral artery was synthesized. Blood flow simulations indicate a consistent trend of higher hematocrit in deeper cortical layers, while surface layers with shorter vascular path lengths seem to carry comparatively lower red blood cell (RBC) concentrations. Moreover, the variability of RBC flux decreases with cortical depth. These results support the notion that plasma skimming serves a self-regulating function for maintaining uniform oxygen perfusion to neurons irrespective of their location in the blood supply hierarchy. Our computations also demonstrate the practicality of simulating blood flow for large portions of the mouse brain with existing computer resources. The efficient simulation of blood flow throughout the entire middle cerebral artery (MCA) territory is a promising milestone towards the final aim of predicting blood flow patterns for the entire brain. The brain’s astonishing cognitive capacity depends on the coordination between neurons and the cerebral circulation, a system known as the neurovascular unit. The spatial and temporal coupling between these two networks is the object of intense research. However, the concise anatomical description of the cerebral circulation has so far been intractable. This paper introduces a methodology for the in silico creation of realistic models for the entire cerebral circulation. This innovation incorporates topological data from several neuroimaging modalities covering three lengths scales as input into a computer algorithm, which assembles anatomically accurate circulatory networks. When simulating blood flow as red blood cells suspended in plasma for experimental and synthetic cortical network models, we discovered that red blood cells tend to be more concentrated in deeper layers of the cortex compared to the surface. RBC fluxes are more homogenous in deeper layers. The phenomenon of depth dependent red blood cell supply supports the notion that the intricate architecture of the cortical microcirculation serves a self-regulating function to maintain uniform oxygen perfusion to neurons. We also demonstrate the practicality of predicting blood flow patterns for the entire brain with existing computer power.
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173
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Shabir O, Berwick J, Francis SE. Neurovascular dysfunction in vascular dementia, Alzheimer's and atherosclerosis. BMC Neurosci 2018; 19:62. [PMID: 30333009 PMCID: PMC6192291 DOI: 10.1186/s12868-018-0465-5] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 10/10/2018] [Indexed: 11/10/2022] Open
Abstract
Efficient blood supply to the brain is of paramount importance to its normal functioning and improper blood flow can result in potentially devastating neurological consequences. Cerebral blood flow in response to neural activity is intrinsically regulated by a complex interplay between various cell types within the brain in a relationship termed neurovascular coupling. The breakdown of neurovascular coupling is evident across a wide variety of both neurological and psychiatric disorders including Alzheimer’s disease. Atherosclerosis is a chronic syndrome affecting the integrity and function of major blood vessels including those that supply the brain, and it is therefore hypothesised that atherosclerosis impairs cerebral blood flow and neurovascular coupling leading to cerebrovascular dysfunction. This review will discuss the mechanisms of neurovascular coupling in health and disease and how atherosclerosis can potentially cause cerebrovascular dysfunction that may lead to cognitive decline as well as stroke. Understanding the mechanisms of neurovascular coupling in health and disease may enable us to develop potential therapies to prevent the breakdown of neurovascular coupling in the treatment of vascular brain diseases including vascular dementia, Alzheimer’s disease and stroke.
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Affiliation(s)
- Osman Shabir
- The Neurovascular and Neuroimaging Research Group, Alfred Denny Building, The University of Sheffield, Western Bank, Sheffield, S10 2TN, UK.
| | - Jason Berwick
- The Neurovascular and Neuroimaging Research Group, Alfred Denny Building, The University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Sheila E Francis
- Department of Infection, Immunity and Cardiovascular Disease, The University of Sheffield, Medical School, Beech Hill Road, Sheffield, S10 2RX, UK
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174
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Taylor S, Mehina E, White E, Reeson P, Yongblah K, Doyle KP, Brown CE. Suppressing Interferon-γ Stimulates Microglial Responses and Repair of Microbleeds in the Diabetic Brain. J Neurosci 2018; 38:8707-8722. [PMID: 30201775 PMCID: PMC6596226 DOI: 10.1523/jneurosci.0734-18.2018] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 07/06/2018] [Accepted: 08/06/2018] [Indexed: 12/15/2022] Open
Abstract
Microcirculatory damage is a common complication for those with vascular risk factors, such as diabetes. To resolve vascular insults, the brain's immune cells (microglia) must rapidly envelop the site of injury. Currently, it is unknown whether Type 1 diabetes, a condition associated with chronic immune system dysfunction, alters microglial responses to damage and what mechanisms are responsible. Using in vivo two-photon microscopy in adult male mice, we show that microglial envelopment of laser-induced cerebral microbleeds is diminished in a hyperglycemic mouse model of Type 1 diabetes, which could not be fully rescued with chronic insulin treatment. Microglia were important for vessel repair because reduced microglial accumulation in diabetic mice or near-complete depletion in healthy controls was associated with greater secondary leakage of the damaged vessel. Broadly suppressing inflammation with dexamethasone in diabetic mice but not healthy controls, significantly enhanced microglial responses to microbleeds and attenuated secondary vessel leakage. These enhancements were associated with changes in IFN-γ signaling because dexamethasone suppressed abnormally high levels of IFN-γ protein levels in brain and blood serum of diabetic mice. Further, blocking IFN-γ in diabetic mice with neutralizing antibodies restored normal microglial chemotaxic responses and purinoceptor P2ry12 gene expression, as well as mitigated secondary leakage. These results suggest that abnormal IFN-γ signaling disrupts microglial function in the diabetic brain, and that immunotherapies targeting IFN-γ can stimulate microglial repair of damaged vessels.SIGNIFICANCE STATEMENT Although Type 1 diabetes is an established risk factor for vascular complications, such as microbleeds, and is known to hinder wound healing in the body, no study has examined how diabetes impacts the brain's innate immune reparative response (involving cells called microglia) to vascular injury. Here we show that microglial responses to brain microbleeds were diminished in diabetic animals, which also exacerbated secondary leakage from damaged vessels. These impairments were related to abnormally high levels of the proinflammatory cytokine IFN-γ because reducing IFN-γ with immunosuppressant drugs or blocking antibodies helped restore normal microglial responses and repair of damaged vessels. These data highlight the use of IFN-γ modulating therapeutics to enhance vascular repair in at-risk populations.
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Affiliation(s)
- Stephanie Taylor
- Division of Medical Sciences, University of Victoria, Victoria, British Columbia V8P 5C2, Canada
| | - Eslam Mehina
- Division of Medical Sciences, University of Victoria, Victoria, British Columbia V8P 5C2, Canada
| | - Emily White
- Division of Medical Sciences, University of Victoria, Victoria, British Columbia V8P 5C2, Canada
| | - Patrick Reeson
- Division of Medical Sciences, University of Victoria, Victoria, British Columbia V8P 5C2, Canada
| | - Kevin Yongblah
- Division of Medical Sciences, University of Victoria, Victoria, British Columbia V8P 5C2, Canada
| | - Kristian P Doyle
- Department of Immunobiology, University of Arizona College of Medicine, Tucson, Arizona 85724, and
| | - Craig E Brown
- Division of Medical Sciences, University of Victoria, Victoria, British Columbia V8P 5C2, Canada,
- Department of Psychiatry, University of British Columbia, Vancouver, British Columbia V6T 2A1, Canada
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175
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Lee S, Kang BM, Kim JH, Min J, Kim HS, Ryu H, Park H, Bae S, Oh D, Choi M, Suh M. Real-time in vivo two-photon imaging study reveals decreased cerebro-vascular volume and increased blood-brain barrier permeability in chronically stressed mice. Sci Rep 2018; 8:13064. [PMID: 30166586 PMCID: PMC6117335 DOI: 10.1038/s41598-018-30875-y] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 08/07/2018] [Indexed: 01/15/2023] Open
Abstract
Chronic stress disrupts brain homeostasis and adversely affects the cerebro-vascular system. Even though the effects of chronic stress on brain system have been extensively studied, there are few in vivo dynamic studies on the effects of chronic stress on the cerebro-vascular system. In this study, the effects of chronic stress on cerebral vasculature and BBB permeability were studied using in vivo two-photon (2p) microscopic imaging with an injection of fluorescence-conjugated dextran. Our real-time 2p imaging results showed that chronic stress reduced the vessel diameter and reconstructed vascular volume, regardless of vessel type and branching order. BBB permeability was investigated with two different size of tracers. Stressed animals exhibited a greater BBB permeability to 40-kDa dextran, but not to 70-kDa dextran, which is suggestive of weakened vascular integrity following stress. Molecular analysis revealed significantly higher VEGFa mRNA expression and a reduction in claudin-5. In summary, chronic stress decreases the size of cerebral vessels and increases BBB permeability. These results may suggest that the sustained decrease in cerebro-vascular volume due to chronic stress leads to a hypoxic condition that causes molecular changes such as VEGF and claudin-5, which eventually impairs the function of BBB.
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Affiliation(s)
- Sohee Lee
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, 16419, Republic of Korea
| | - Bok-Man Kang
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, 16419, Republic of Korea.,Department of Biomedical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Jae Hwan Kim
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, 16419, Republic of Korea.,Biomedical Institute for Convergence at SKKU (BICS), Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Jiwoong Min
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, 16419, Republic of Korea.,Department of Biomedical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Hyung Seok Kim
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, 16419, Republic of Korea.,Department of Biomedical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Hyunwoo Ryu
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, 16419, Republic of Korea.,Department of Biomedical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Hyejin Park
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, 16419, Republic of Korea.,Biomedical Institute for Convergence at SKKU (BICS), Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea.,Department of Biological Science, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Sungjun Bae
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, 16419, Republic of Korea.,Department of Biomedical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Daehwan Oh
- Biomedical Institute for Convergence at SKKU (BICS), Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Myunghwan Choi
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, 16419, Republic of Korea.,Department of Biomedical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea.,Biomedical Institute for Convergence at SKKU (BICS), Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Minah Suh
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, 16419, Republic of Korea. .,Department of Biomedical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea. .,Biomedical Institute for Convergence at SKKU (BICS), Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea. .,Samsung Advanced Institute of Health Science and Technology (SAIHST), Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea.
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176
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Yuan Y, Wang Z, Wang X, Yan J, Liu M, Li X. Low-Intensity Pulsed Ultrasound Stimulation Induces Coupling Between Ripple Neural Activity and Hemodynamics in the Mouse Visual Cortex. Cereb Cortex 2018; 29:3220-3223. [DOI: 10.1093/cercor/bhy187] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Indexed: 12/19/2022] Open
Abstract
Abstract
Several studies have separately investigated neural activities and hemodynamic responses induced by low-intensity pulsed ultrasound stimulation (LIPUS), less is known about their coupling under LIPUS. This study aims to investigate the neurovascular coupling with LIPUS by measuring neural activity and hemodynamics. We found that the relative power and sample entropy of local field potential at the ripple band have a significant correlation to relative cerebral blood flow over time (correlation coefficients: 0.66 ± 0.13 [P < 0.01] and −0.58 ± 0.11 [P < 0.05]). These results demonstrate that LIPUS can induce neurovascular coupling in the mouse visual cortex.
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Affiliation(s)
- Yi Yuan
- Institute of Electrical Engineering, Yanshan University, Qinhuangdao, China
| | - Zhijie Wang
- Institute of Electrical Engineering, Yanshan University, Qinhuangdao, China
| | - Xingran Wang
- Institute of Electrical Engineering, Yanshan University, Qinhuangdao, China
| | - Jiaqing Yan
- College of Electrical and Control Engineering, North China University of Technology, Beijing, China
| | - Mengyang Liu
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna , Austria
| | - Xiaoli Li
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China
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177
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Jones JS, Small DM, Nishimura N. In Vivo Calcium Imaging of Cardiomyocytes in the Beating Mouse Heart With Multiphoton Microscopy. Front Physiol 2018; 9:969. [PMID: 30108510 PMCID: PMC6079295 DOI: 10.3389/fphys.2018.00969] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Accepted: 07/02/2018] [Indexed: 12/22/2022] Open
Abstract
Background: Understanding the microscopic dynamics of the beating heart has been challenging due to the technical nature of imaging with micrometer resolution while the heart moves. The development of multiphoton microscopy has made in vivo, cell-resolved measurements of calcium dynamics and vascular function possible in motionless organs such as the brain. In heart, however, studies of in vivo interactions between cells and the native microenvironment are behind other organ systems. Our goal was to develop methods for intravital imaging of cardiac structural and calcium dynamics with microscopic resolution. Methods: Ventilated mice expressing GCaMP6f, a genetically encoded calcium indicator, received a thoracotomy to provide optical access to the heart. Vasculature was labeled with an injection of dextran-labeled dye. The heart was partially stabilized by a titanium probe with a glass window. Images were acquired at 30 frames per second with spontaneous heartbeat and continuously running, ventilated breathing. The data were reconstructed into three-dimensional volumes showing tissue structure, vasculature, and GCaMP6f signal in cardiomyocytes as a function of both the cardiac and respiratory cycle. Results: We demonstrated the capability to simultaneously measure calcium transients, vessel size, and tissue displacement in three dimensions with micrometer resolution. Reconstruction at various combinations of cardiac and respiratory phase enabled measurement of regional and single-cell cardiomyocyte calcium transients (GCaMP6f fluorescence). GCaMP6f fluorescence transients in individual, aberrantly firing cardiomyocytes were also quantified. Comparisons of calcium dynamics (rise-time and tau) at varying positions within the ventricle wall showed no significant depth dependence. Conclusion: This method enables studies of coupling between contraction and excitation during physiological blood perfusion and breathing at high spatiotemporal resolution. These capabilities could lead to a new understanding of normal and disease function of cardiac cells.
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Affiliation(s)
- Jason S Jones
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States
| | - David M Small
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States
| | - Nozomi Nishimura
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States
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178
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Kelly P, Hudry E, Hou SS, Bacskai BJ. In Vivo Two Photon Imaging of Astrocytic Structure and Function in Alzheimer's Disease. Front Aging Neurosci 2018; 10:219. [PMID: 30072889 PMCID: PMC6060286 DOI: 10.3389/fnagi.2018.00219] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 06/26/2018] [Indexed: 12/17/2022] Open
Abstract
The physiological function of the neurovascular unit is critically dependent upon the complex structure and functions of astrocytes for optimal preservation of cerebral homeostasis. While it has been shown that astrocytes exhibit aberrant changes in both structure and function in transgenic murine models of Alzheimer’s disease (AD), it is not fully understood how this altered phenotype contributes to the pathogenesis of AD or whether this alteration predicts a therapeutic target in AD. The mechanisms underlying the spatiotemporal relationship between astrocytes, neurons and the vasculature in their orchestrated regulation of local cerebral flow in active brain regions has not been fully elucidated in brain physiology and in AD. As there is an incredible urgency to identify therapeutic targets that are well-tolerated and efficacious in protecting the brain against the pathological impact of AD, here we use the current body of literature to evaluate the hypothesis that pathological changes in astrocytes are central to the pathogenesis of AD. We also examine the current tools available to assess astrocytic calcium signaling in the living murine brain as it has an important role in the complex interaction between astrocytes, neurons and the vasculature. Furthermore, we discuss the altered function of astrocytes in their interaction with neurons in the preservation of glutamate homeostasis and additionally address the role of astrocytes at the vascular interface and their contribution to functional hyperemia within the living murine brain in health and in AD.
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Affiliation(s)
- Patricia Kelly
- Massachusetts Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Harvard University, Boston, MA, United States
| | - Eloise Hudry
- Massachusetts Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Harvard University, Boston, MA, United States
| | - Steven S Hou
- Massachusetts Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Harvard University, Boston, MA, United States
| | - Brian J Bacskai
- Massachusetts Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Harvard University, Boston, MA, United States
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179
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Stimulation-induced increases in cerebral blood flow and local capillary vasoconstriction depend on conducted vascular responses. Proc Natl Acad Sci U S A 2018; 115:E5796-E5804. [PMID: 29866853 DOI: 10.1073/pnas.1707702115] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Functional neuroimaging, such as fMRI, is based on coupling neuronal activity and accompanying changes in cerebral blood flow (CBF) and metabolism. However, the relationship between CBF and events at the level of the penetrating arterioles and capillaries is not well established. Recent findings suggest an active role of capillaries in CBF control, and pericytes on capillaries may be major regulators of CBF and initiators of functional imaging signals. Here, using two-photon microscopy of brains in living mice, we demonstrate that stimulation-evoked increases in synaptic activity in the mouse somatosensory cortex evokes capillary dilation starting mostly at the first- or second-order capillary, propagating upstream and downstream at 5-20 µm/s. Therefore, our data support an active role of pericytes in cerebrovascular control. The gliotransmitter ATP applied to first- and second-order capillaries by micropipette puffing induced dilation, followed by constriction, which also propagated at 5-20 µm/s. ATP-induced capillary constriction was blocked by purinergic P2 receptors. Thus, conducted vascular responses in capillaries may be a previously unidentified modulator of cerebrovascular function and functional neuroimaging signals.
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180
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Michelson NJ, Vazquez AL, Eles JR, Salatino JW, Purcell EK, Williams JJ, Cui XT, Kozai TDY. Multi-scale, multi-modal analysis uncovers complex relationship at the brain tissue-implant neural interface: new emphasis on the biological interface. J Neural Eng 2018; 15:033001. [PMID: 29182149 PMCID: PMC5967409 DOI: 10.1088/1741-2552/aa9dae] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVE Implantable neural electrode devices are important tools for neuroscience research and have an increasing range of clinical applications. However, the intricacies of the biological response after implantation, and their ultimate impact on recording performance, remain challenging to elucidate. Establishing a relationship between the neurobiology and chronic recording performance is confounded by technical challenges related to traditional electrophysiological, material, and histological limitations. This can greatly impact the interpretations of results pertaining to device performance and tissue health surrounding the implant. APPROACH In this work, electrophysiological activity and immunohistological analysis are compared after controlling for motion artifacts, quiescent neuronal activity, and material failure of devices in order to better understand the relationship between histology and electrophysiological outcomes. MAIN RESULTS Even after carefully accounting for these factors, the presence of viable neurons and lack of glial scarring does not convey single unit recording performance. SIGNIFICANCE To better understand the biological factors influencing neural activity, detailed cellular and molecular tissue responses were examined. Decreases in neural activity and blood oxygenation in the tissue surrounding the implant, shift in expression levels of vesicular transporter proteins and ion channels, axon and myelin injury, and interrupted blood flow in nearby capillaries can impact neural activity around implanted neural interfaces. Combined, these tissue changes highlight the need for more comprehensive, basic science research to elucidate the relationship between biology and chronic electrophysiology performance in order to advance neural technologies.
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Affiliation(s)
| | - Alberto L Vazquez
- Department of Bioengineering, University of Pittsburgh
- Department of Radiology, University of Pittsburgh
- Center for the Neural Basis of Cognition, University of Pittsburgh
- Center for Neuroscience, University of Pittsburgh
| | - James R Eles
- Department of Bioengineering, University of Pittsburgh
- Center for the Neural Basis of Cognition, University of Pittsburgh
| | | | - Erin K Purcell
- Department of Biomedical Engineering, Michigan State University
| | | | - X. Tracy Cui
- Department of Bioengineering, University of Pittsburgh
- Center for the Neural Basis of Cognition, University of Pittsburgh
- McGowan Institute of Regenerative Medicine, University of Pittsburgh
| | - Takashi DY Kozai
- Department of Bioengineering, University of Pittsburgh
- Center for the Neural Basis of Cognition, University of Pittsburgh
- Center for Neuroscience, University of Pittsburgh
- McGowan Institute of Regenerative Medicine, University of Pittsburgh
- NeuroTech Center, University of Pittsburgh Brain Institute
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181
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Gómez CA, Sutin J, Wu W, Fu B, Uhlirova H, Devor A, Boas DA, Sakadžić S, Yaseen MA. Phasor analysis of NADH FLIM identifies pharmacological disruptions to mitochondrial metabolic processes in the rodent cerebral cortex. PLoS One 2018; 13:e0194578. [PMID: 29561904 PMCID: PMC5862490 DOI: 10.1371/journal.pone.0194578] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 03/06/2018] [Indexed: 01/20/2023] Open
Abstract
Investigating cerebral metabolism in vivo at a microscopic level is essential for understanding brain function and its pathological alterations. The intricate signaling and metabolic dynamics between neurons, glia, and microvasculature requires much more detailed understanding to better comprehend the mechanisms governing brain function and its disease-related changes. We recently demonstrated that pharmacologically-induced alterations to different steps of cerebral metabolism can be distinguished utilizing 2-photon fluorescence lifetime imaging of endogenous reduced nicotinamide adenine dinucleotide (NADH) fluorescence in vivo. Here, we evaluate the ability of the phasor analysis method to identify these pharmacological metabolic alterations and compare the method's performance with more conventional nonlinear curve-fitting analysis. Visualization of phasor data, both at the fundamental laser repetition frequency and its second harmonic, enables resolution of pharmacologically-induced alterations to mitochondrial metabolic processes from baseline cerebral metabolism. Compared to our previous classification models based on nonlinear curve-fitting, phasor-based models required fewer parameters and yielded comparable or improved classification accuracy. Fluorescence lifetime imaging of NADH and phasor analysis shows utility for detecting metabolic alterations and will lead to a deeper understanding of cerebral energetics and its pathological changes.
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Affiliation(s)
- Carlos A. Gómez
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States of America
| | - Jason Sutin
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States of America
| | - Weicheng Wu
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States of America
| | - Buyin Fu
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States of America
| | - Hana Uhlirova
- Department of Neurosciences and Radiology, UC San Diego, La Jolla, CA, United States of America
- Central European Institute of Technology, Brno University of Technology, Brno, Czech Republic
| | - Anna Devor
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States of America
- Department of Neurosciences and Radiology, UC San Diego, La Jolla, CA, United States of America
| | - David A. Boas
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States of America
| | - Sava Sakadžić
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States of America
| | - Mohammad A. Yaseen
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States of America
- * E-mail:
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182
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Neumann J, Henneberg S, von Kenne S, Nolte N, Müller AJ, Schraven B, Görtler MW, Reymann KG, Gunzer M, Riek-Burchardt M. Beware the intruder: Real time observation of infiltrated neutrophils and neutrophil-Microglia interaction during stroke in vivo. PLoS One 2018; 13:e0193970. [PMID: 29543836 PMCID: PMC5854356 DOI: 10.1371/journal.pone.0193970] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 02/22/2018] [Indexed: 01/08/2023] Open
Abstract
Inflammation plays an important role in the pathogenesis of ischemic stroke including an acute and prolonged inflammatory process. The role of neutrophil granulocytes as first driver of the immune reaction from the blood site is under debate due to controversial findings. In bone marrow chimeric mice we were able to study the dynamics of tdTomato-expressing neutrophils and GFP-expressing microglia after photothrombosis using intravital two-photon microscopy. We demonstrate the infiltration of neutrophils into the brain parenchyma and confirm a long-lasting contact between neutrophils and microglia as well as an uptake of neutrophils by microglia clearing the brain from peripheral immune cells.
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Affiliation(s)
- Jens Neumann
- Department of Neurology, Medical Faculty, Otto-von-Guericke University Magdeburg, Germany
- * E-mail: (MRB); (JN)
| | - Sophie Henneberg
- Institute for Experimental Immunology and Imaging, Medical Faculty, Essen, University Duisburg-Essen, Germany
| | - Susanne von Kenne
- Department of Neurology, Medical Faculty, Otto-von-Guericke University Magdeburg, Germany
| | - Niklas Nolte
- Institute for Molecular and Clinical Immunology, Medical Faculty, Otto-von-Guericke University Magdeburg, Germany
| | - Andreas J. Müller
- Institute for Molecular and Clinical Immunology, Medical Faculty, Otto-von-Guericke University Magdeburg, Germany
- Helmholtz Center for Infection Research, Braunschweig, Germany
| | - Burkhart Schraven
- Institute for Molecular and Clinical Immunology, Medical Faculty, Otto-von-Guericke University Magdeburg, Germany
| | - Michael W. Görtler
- Department of Neurology, Medical Faculty, Otto-von-Guericke University Magdeburg, Germany
| | - Klaus G. Reymann
- Project Group Neuropharmacology, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Matthias Gunzer
- Institute for Experimental Immunology and Imaging, Medical Faculty, Essen, University Duisburg-Essen, Germany
| | - Monika Riek-Burchardt
- Institute for Molecular and Clinical Immunology, Medical Faculty, Otto-von-Guericke University Magdeburg, Germany
- * E-mail: (MRB); (JN)
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183
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Manglani M, McGavern DB. Intravital Imaging of Neuroimmune Interactions Through a Thinned Skull. ACTA ACUST UNITED AC 2018; 120:24.2.1-24.2.12. [PMID: 29512146 DOI: 10.1002/cpim.46] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Innate and adaptive immune interactions within the central nervous system (CNS) and surrounding meninges contribute significantly to neural homeostasis as well as a variety of different neurological disorders. Two-photon laser scanning microscopy is a deep tissue imaging technique that provides a means to image immune cell dynamics and interactions in the living CNS with high spatial and temporal resolution. Optical access to the brain and meninges can be achieved through the creation of thinned skull windows, which can be made without inducing damage and inflammation in the underlying tissue. This protocol provides guidance on how to create a thinned skull window without causing CNS injury. We also describe a highly reproducible method to induce a mild traumatic brain injury using the thinned skull approach. © 2018 by John Wiley & Sons, Inc.
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Affiliation(s)
- Monica Manglani
- Viral Immunology and Intravital Imaging Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland.,Medical Scientist Training Program, Pennsylvania State College of Medicine, Hershey, Pennsylvania
| | - Dorian B McGavern
- Viral Immunology and Intravital Imaging Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
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184
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Rasmussen PM, Smith AF, Sakadžić S, Boas DA, Pries AR, Secomb TW, Østergaard L. Model-based inference from microvascular measurements: Combining experimental measurements and model predictions using a Bayesian probabilistic approach. Microcirculation 2018; 24. [PMID: 27987383 DOI: 10.1111/micc.12343] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 12/12/2016] [Indexed: 01/23/2023]
Abstract
OBJECTIVE In vivo imaging of the microcirculation and network-oriented modeling have emerged as powerful means of studying microvascular function and understanding its physiological significance. Network-oriented modeling may provide the means of summarizing vast amounts of data produced by high-throughput imaging techniques in terms of key, physiological indices. To estimate such indices with sufficient certainty, however, network-oriented analysis must be robust to the inevitable presence of uncertainty due to measurement errors as well as model errors. METHODS We propose the Bayesian probabilistic data analysis framework as a means of integrating experimental measurements and network model simulations into a combined and statistically coherent analysis. The framework naturally handles noisy measurements and provides posterior distributions of model parameters as well as physiological indices associated with uncertainty. RESULTS We applied the analysis framework to experimental data from three rat mesentery networks and one mouse brain cortex network. We inferred distributions for more than 500 unknown pressure and hematocrit boundary conditions. Model predictions were consistent with previous analyses, and remained robust when measurements were omitted from model calibration. CONCLUSION Our Bayesian probabilistic approach may be suitable for optimizing data acquisition and for analyzing and reporting large data sets acquired as part of microvascular imaging studies.
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Affiliation(s)
- Peter M Rasmussen
- Department of Clinical Medicine, Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University Hospital, Aarhus, Denmark
| | - Amy F Smith
- Institut de Mécanique des Fluides de Toulouse (IMFT) - Université de Toulouse, CNRS-INPT-UPS, Toulouse, France
| | - Sava Sakadžić
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - David A Boas
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA.,Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, USA
| | - Axel R Pries
- Department of Physiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Timothy W Secomb
- Department of Physiology, University of Arizona, Tucson, AZ, USA
| | - Leif Østergaard
- Department of Clinical Medicine, Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University Hospital, Aarhus, Denmark.,Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark
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185
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Kirschen GW, Kéry R, Liu H, Ahamad A, Chen L, Akmentin W, Kumar R, Levine J, Xiong Q, Ge S. Genetic dissection of the neuro-glio-vascular machinery in the adult brain. Mol Brain 2018; 11:2. [PMID: 29335006 PMCID: PMC5769320 DOI: 10.1186/s13041-017-0345-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 12/21/2017] [Indexed: 12/30/2022] Open
Abstract
The adult brain actively controls its metabolic homeostasis via the circulatory system at the blood brain barrier interface. The mechanisms underlying the functional coupling from neuron to vessel remain poorly understood. Here, we established a novel method to genetically isolate the individual components of this coupling machinery using a combination of viral vectors. We first discovered a surprising non-uniformity of the glio-vascular structure in different brain regions. We carried out a viral injection screen and found that intravenous Canine Adenovirus 2 (CAV2) preferentially targeted perivascular astrocytes throughout the adult brain, with sparing of the hippocampal hilus from infection. Using this new intravenous method to target astrocytes, we selectively ablated these cells and observed severe defects in hippocampus-dependent contextual memory and the metabolically regulated process of hippocampal neurogenesis. Combined with AAV9 targeting of neurons and endothelial cells, all components of the neuro-glio-vascular machinery can be simultaneously labeled for genetic manipulation. Together, we demonstrate a novel method, which we term CATNAP (CAV/AAV Targeting of Neurons and Astrocytes Perivascularly), to target and manipulate the neuro-glio-vascular machinery in the adult brain.
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Affiliation(s)
- Gregory W Kirschen
- Medical Scientist Training Program, Stony Brook, New York, USA.,Department of Neurobiology & Behavior, SUNY Stony Brook, Stony Brook, NY, 11794, USA
| | - Rachel Kéry
- Medical Scientist Training Program, Stony Brook, New York, USA.,Department of Neurobiology & Behavior, SUNY Stony Brook, Stony Brook, NY, 11794, USA
| | - Hanxiao Liu
- Department of Neurobiology & Behavior, SUNY Stony Brook, Stony Brook, NY, 11794, USA
| | - Afrinash Ahamad
- School of Health Technology & Management, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Liang Chen
- Department of Neurobiology & Behavior, SUNY Stony Brook, Stony Brook, NY, 11794, USA
| | - Wendy Akmentin
- Department of Neurobiology & Behavior, SUNY Stony Brook, Stony Brook, NY, 11794, USA
| | - Ramya Kumar
- Department of Neurobiology & Behavior, SUNY Stony Brook, Stony Brook, NY, 11794, USA
| | - Joel Levine
- Department of Neurobiology & Behavior, SUNY Stony Brook, Stony Brook, NY, 11794, USA
| | - Qiaojie Xiong
- Department of Neurobiology & Behavior, SUNY Stony Brook, Stony Brook, NY, 11794, USA.
| | - Shaoyu Ge
- Department of Neurobiology & Behavior, SUNY Stony Brook, Stony Brook, NY, 11794, USA.
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186
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Peyrounette M, Davit Y, Quintard M, Lorthois S. Multiscale modelling of blood flow in cerebral microcirculation: Details at capillary scale control accuracy at the level of the cortex. PLoS One 2018; 13:e0189474. [PMID: 29324784 PMCID: PMC5764267 DOI: 10.1371/journal.pone.0189474] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 11/28/2017] [Indexed: 11/19/2022] Open
Abstract
Aging or cerebral diseases may induce architectural modifications in human brain microvascular networks, such as capillary rarefaction. Such modifications limit blood and oxygen supply to the cortex, possibly resulting in energy failure and neuronal death. Modelling is key in understanding how these architectural modifications affect blood flow and mass transfers in such complex networks. However, the huge number of vessels in the human brain—tens of billions—prevents any modelling approach with an explicit architectural representation down to the scale of the capillaries. Here, we introduce a hybrid approach to model blood flow at larger scale in the brain microcirculation, based on its multiscale architecture. The capillary bed, which is a space-filling network, is treated as a porous medium and modelled using a homogenized continuum approach. The larger arteriolar and venular trees, which cannot be homogenized because of their fractal-like nature, are treated as a network of interconnected tubes with a detailed representation of their spatial organization. The main contribution of this work is to devise a proper coupling model at the interface between these two components. This model is based on analytical approximations of the pressure field that capture the strong pressure gradients building up in the capillaries connected to arterioles or venules. We evaluate the accuracy of this model for both very simple architectures with one arteriole and/or one venule and for more complex ones, with anatomically realistic tree-like vessels displaying a large number of coupling sites. We show that the hybrid model is very accurate in describing blood flow at large scales and further yields a significant computational gain by comparison with a classical network approach. It is therefore an important step towards large scale simulations of cerebral blood flow and lays the groundwork for introducing additional levels of complexity in the future.
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Affiliation(s)
- Myriam Peyrounette
- Institut de Mécanique des Fluides de Toulouse, IMFT, Université de Toulouse, CNRS - Toulouse, France
| | - Yohan Davit
- Institut de Mécanique des Fluides de Toulouse, IMFT, Université de Toulouse, CNRS - Toulouse, France
| | - Michel Quintard
- Institut de Mécanique des Fluides de Toulouse, IMFT, Université de Toulouse, CNRS - Toulouse, France
| | - Sylvie Lorthois
- Institut de Mécanique des Fluides de Toulouse, IMFT, Université de Toulouse, CNRS - Toulouse, France
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States of America
- * E-mail:
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187
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Bollu T, Cornelius NR, Sunwoo J, Nishimura N, Schaffer CB, Doerschuk PC. Experimentally constrained circuit model of cortical arteriole networks for understanding flow redistribution due to occlusion and neural activation. J Cereb Blood Flow Metab 2018; 38:38-44. [PMID: 29130779 PMCID: PMC5757444 DOI: 10.1177/0271678x17741086] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Computations are described which estimate flows in all branches of the cortical surface arteriole network from two-photon excited fluorescence (2PEF) microscopy images which provide the network topology and, in selected branches red blood cell (RBC) speeds and lumen diameters. Validation is done by comparing the flow predicted by the model with experimentally measured flows and by comparing the predicted flow redistribution in the network due to single-vessel strokes with experimental observations. The model predicts that tissue is protected from RBC flow decreases caused by multiple occlusions of surface arterioles but not penetrating arterioles. The model can also be used to study flow rerouting due to vessel dilations and constrictions.
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Affiliation(s)
- Tejapratap Bollu
- 1 Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA
| | - Nathan R Cornelius
- 1 Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA
| | - John Sunwoo
- 1 Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA
| | - Nozomi Nishimura
- 1 Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA
| | - Chris B Schaffer
- 1 Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA
| | - Peter C Doerschuk
- 1 Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA.,2 School of Electrical and Computer Engineering, Cornell University, Ithaca, NY, USA
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188
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Zhang JH, Obenaus A, Liebeskind DS, Tang J, Hartman R, Pearce WJ. Recanalization, reperfusion, and recirculation in stroke. J Cereb Blood Flow Metab 2017; 37:3818-3823. [PMID: 28925323 PMCID: PMC5718333 DOI: 10.1177/0271678x17732695] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Recirculation, from arterial inflow routes through venous outflow pathways, was conceptualized in stroke research 50 years ago. As new technologies were developed, blocked arteries could be reopened, capillaries could be reperfused, and the use of recanalization and reperfusion grew to dominate therapeutic strategies. These approaches overwhelmingly focused on restoration of arterial and capillary inflow, but not on veins even though venous disorders may initiate or exacerbate brain injury. In this commentary, we advance the term "recirculation" after "recanalization" and "reperfusion" as a primary concept of stroke pathophysiology that targets the restoration of both the arterial and venous cerebral circulations.
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Affiliation(s)
- John H Zhang
- 1 Center for Neuroscience Research, 4608 Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Andre Obenaus
- 1 Center for Neuroscience Research, 4608 Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - David S Liebeskind
- 2 Neurovascular Imaging Research Core and Department of Neurology, UCLA, CA, USA
| | - Jiping Tang
- 1 Center for Neuroscience Research, 4608 Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Richard Hartman
- 1 Center for Neuroscience Research, 4608 Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - William J Pearce
- 1 Center for Neuroscience Research, 4608 Loma Linda University School of Medicine, Loma Linda, CA, USA
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189
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Miller DR, Jarrett JW, Hassan AM, Dunn AK. Deep Tissue Imaging with Multiphoton Fluorescence Microscopy. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2017; 4:32-39. [PMID: 29335679 PMCID: PMC5766275 DOI: 10.1016/j.cobme.2017.09.004] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We present a review of imaging deep-tissue structures with multiphoton microscopy. We examine the effects of light scattering and absorption due to the optical properties of biological sample and identify 1,300 nm and 1,700 nm as ideal excitation wavelengths. We summarize the availability of fluorophores for multiphoton microscopy as well as ultrafast laser sources to excite available fluorophores. Lastly, we discuss the applications of multiphoton microscopy for neuroscience.
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Affiliation(s)
- David R Miller
- Department of Biomedical Engineering, The University of Texas at Austin, 107 W. Dean Keeton C0800, Austin, TX 78712, USA
| | - Jeremy W Jarrett
- Department of Biomedical Engineering, The University of Texas at Austin, 107 W. Dean Keeton C0800, Austin, TX 78712, USA
| | - Ahmed M Hassan
- Department of Biomedical Engineering, The University of Texas at Austin, 107 W. Dean Keeton C0800, Austin, TX 78712, USA
| | - Andrew K Dunn
- Department of Biomedical Engineering, The University of Texas at Austin, 107 W. Dean Keeton C0800, Austin, TX 78712, USA
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190
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Knutsen PM, Mateo C, Kleinfeld D. Precision mapping of the vibrissa representation within murine primary somatosensory cortex. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0351. [PMID: 27574305 DOI: 10.1098/rstb.2015.0351] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/11/2016] [Indexed: 11/12/2022] Open
Abstract
The ability to form an accurate map of sensory input to the brain is an essential aspect of interpreting functional brain signals. Here, we consider the somatotopic map of vibrissa-based touch in the primary somatosensory (vS1) cortex of mice. The vibrissae are represented by a Manhattan-like grid of columnar structures that are separated by inter-digitating septa. The development, dynamics and plasticity of this organization is widely used as a model system. Yet, the exact anatomical position of this organization within the vS1 cortex varies between individual mice. Targeting of a particular column in vivo therefore requires prior mapping of the activated cortical region, for instance by imaging the evoked intrinsic optical signal (eIOS) during vibrissa stimulation. Here, we describe a procedure for constructing a complete somatotopic map of the vibrissa representation in the vS1 cortex using eIOS. This enables precise targeting of individual cortical columns. We found, using C57BL/6 mice, that although the precise location of the columnar field varies between animals, the relative spatial arrangement of the columns is highly preserved. This finding enables us to construct a canonical somatotopic map of the vibrissae in the vS1 cortex. In particular, the position of any column, in absolute anatomical coordinates, can be established with near certainty when the functional representations in the vS1 cortex for as few as two vibrissae have been mapped with eIOS.This article is part of the themed issue 'Interpreting BOLD: a dialogue between cognitive and cellular neuroscience'.
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Affiliation(s)
- Per M Knutsen
- Department of Physics, UC San Diego, La Jolla, CA, USA
| | - Celine Mateo
- Department of Physics, UC San Diego, La Jolla, CA, USA
| | - David Kleinfeld
- Department of Physics, UC San Diego, La Jolla, CA, USA Section of Neurobiology, UC San Diego, La Jolla, CA, USA Department of Electrical and Computer Engineering, UC San Diego, La Jolla, CA, USA
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191
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Bixel MG, Kusumbe AP, Ramasamy SK, Sivaraj KK, Butz S, Vestweber D, Adams RH. Flow Dynamics and HSPC Homing in Bone Marrow Microvessels. Cell Rep 2017; 18:1804-1816. [PMID: 28199850 PMCID: PMC5318670 DOI: 10.1016/j.celrep.2017.01.042] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 11/28/2016] [Accepted: 01/18/2017] [Indexed: 12/17/2022] Open
Abstract
Measurements of flow velocities at the level of individual arterial vessels and sinusoidal capillaries are crucial for understanding the dynamics of hematopoietic stem and progenitor cell homing in the bone marrow vasculature. We have developed two complementary intravital two-photon imaging approaches to determine blood flow dynamics and velocities in multiple vessel segments by capturing the motion of red blood cells. High-resolution spatiotemporal measurements through a cranial window to determine short-time dynamics of flowing blood cells and repetitive centerline scans were used to obtain a detailed flow-profile map with hemodynamic parameters. In addition, we observed the homing of individual hematopoietic stem and progenitor cells and obtained detailed information on their homing behavior. With our imaging setup, we determined flow patterns at cellular resolution, blood flow velocities and wall shear stress in small arterial vessels and highly branched sinusoidal capillaries, and the cellular dynamics of hematopoietic stem and progenitor cell homing.
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Affiliation(s)
- M Gabriele Bixel
- Department of Tissue Morphogenesis, Max Planck Institute for Molecular Biomedicine, 48149 Münster, Germany; Faculty of Medicine, University of Münster, 48149 Münster, Germany.
| | - Anjali P Kusumbe
- Department of Tissue Morphogenesis, Max Planck Institute for Molecular Biomedicine, 48149 Münster, Germany
| | - Saravana K Ramasamy
- Department of Tissue Morphogenesis, Max Planck Institute for Molecular Biomedicine, 48149 Münster, Germany
| | - Kishor K Sivaraj
- Department of Tissue Morphogenesis, Max Planck Institute for Molecular Biomedicine, 48149 Münster, Germany
| | - Stefan Butz
- Department of Vascular Cell Biology, Max Planck Institute for Molecular Biomedicine, 48149 Münster, Germany
| | - Dietmar Vestweber
- Department of Vascular Cell Biology, Max Planck Institute for Molecular Biomedicine, 48149 Münster, Germany
| | - Ralf H Adams
- Department of Tissue Morphogenesis, Max Planck Institute for Molecular Biomedicine, 48149 Münster, Germany; Faculty of Medicine, University of Münster, 48149 Münster, Germany.
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192
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Mateo C, Knutsen PM, Tsai PS, Shih AY, Kleinfeld D. Entrainment of Arteriole Vasomotor Fluctuations by Neural Activity Is a Basis of Blood-Oxygenation-Level-Dependent "Resting-State" Connectivity. Neuron 2017; 96:936-948.e3. [PMID: 29107517 PMCID: PMC5851777 DOI: 10.1016/j.neuron.2017.10.012] [Citation(s) in RCA: 183] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 09/04/2017] [Accepted: 10/05/2017] [Indexed: 01/12/2023]
Abstract
Resting-state signals in blood-oxygenation-level-dependent (BOLD) imaging are used to parcellate brain regions and define "functional connections" between regions. Yet a physiological link between fluctuations in blood oxygenation with those in neuronal signaling pathways is missing. We present evidence from studies on mouse cortex that modulation of vasomotion, i.e., intrinsic ultra-slow (0.1 Hz) fluctuations in arteriole diameter, provides this link. First, ultra-slow fluctuations in neuronal signaling, which occur as an envelope over γ-band activity, entrains vasomotion. Second, optogenetic manipulations confirm that entrainment is unidirectional. Third, co-fluctuations in the diameter of pairs of arterioles within the same hemisphere diminish to chance for separations >1.4 mm. Yet the diameters of arterioles in distant (>5 mm), mirrored transhemispheric sites strongly co-fluctuate; these correlations are diminished in acallosal mice. Fourth, fluctuations in arteriole diameter coherently drive fluctuations in blood oxygenation. Thus, entrainment of vasomotion links neuronal pathways to functional connections.
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Affiliation(s)
- Celine Mateo
- Department of Physics, University of California, San Diego, La Jolla, CA, USA
| | - Per M Knutsen
- Department of Physics, University of California, San Diego, La Jolla, CA, USA
| | - Philbert S Tsai
- Department of Physics, University of California, San Diego, La Jolla, CA, USA
| | - Andy Y Shih
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC, USA
| | - David Kleinfeld
- Department of Physics, University of California, San Diego, La Jolla, CA, USA; Section of Neurobiology, University of California, San Diego, La Jolla, CA, USA.
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193
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Summers PM, Hartmann DA, Hui ES, Nie X, Deardorff RL, McKinnon ET, Helpern JA, Jensen JH, Shih AY. Functional deficits induced by cortical microinfarcts. J Cereb Blood Flow Metab 2017; 37:3599-3614. [PMID: 28090802 PMCID: PMC5669342 DOI: 10.1177/0271678x16685573] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Clinical studies have revealed a strong link between increased burden of cerebral microinfarcts and risk for cognitive impairment. Since the sum of tissue damage incurred by microinfarcts is a miniscule percentage of total brain volume, we hypothesized that microinfarcts disrupt brain function beyond the injury site visible to histological or radiological examination. We tested this idea using a mouse model of microinfarcts, where single penetrating vessels that supply mouse cortex were occluded by targeted photothrombosis. We found that in vivo structural and diffusion MRI reliably reported the acute microinfarct core, based on spatial co-registrations with post-mortem stains of neuronal viability. Consistent with our hypothesis, c-Fos assays for neuronal activity and in vivo imaging of single vessel hemodynamics both reported functional deficits in viable peri-lesional tissues beyond the microinfarct core. We estimated that the volume of tissue with functional deficit in cortex was at least 12-fold greater than the volume of the microinfarct core. Impaired hemodynamic responses in peri-lesional tissues persisted at least 14 days, and were attributed to lasting deficits in neuronal circuitry or neurovascular coupling. These data show how individually miniscule microinfarcts could contribute to broader brain dysfunction during vascular cognitive impairment and dementia.
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Affiliation(s)
- Philipp M Summers
- 1 Department of Neurosciences, Medical University of South Carolina, Charleston, SC, USA
| | - David A Hartmann
- 1 Department of Neurosciences, Medical University of South Carolina, Charleston, SC, USA
| | - Edward S Hui
- 2 Department of Diagnostic Radiology, The University of Hong Kong, Hong Kong
| | - Xingju Nie
- 3 Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA.,4 Center for Biomedical Imaging, Medical University of South Carolina, Charleston, SC, USA
| | - Rachael L Deardorff
- 3 Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA.,4 Center for Biomedical Imaging, Medical University of South Carolina, Charleston, SC, USA
| | - Emilie T McKinnon
- 3 Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA.,4 Center for Biomedical Imaging, Medical University of South Carolina, Charleston, SC, USA
| | - Joseph A Helpern
- 1 Department of Neurosciences, Medical University of South Carolina, Charleston, SC, USA.,3 Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA.,4 Center for Biomedical Imaging, Medical University of South Carolina, Charleston, SC, USA
| | - Jens H Jensen
- 3 Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA.,4 Center for Biomedical Imaging, Medical University of South Carolina, Charleston, SC, USA
| | - Andy Y Shih
- 1 Department of Neurosciences, Medical University of South Carolina, Charleston, SC, USA.,4 Center for Biomedical Imaging, Medical University of South Carolina, Charleston, SC, USA
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194
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Disturbances in the control of capillary flow in an aged APP swe/PS1ΔE9 model of Alzheimer's disease. Neurobiol Aging 2017; 62:82-94. [PMID: 29131981 DOI: 10.1016/j.neurobiolaging.2017.10.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 10/04/2017] [Accepted: 10/06/2017] [Indexed: 02/08/2023]
Abstract
Vascular changes are thought to contribute to the development of Alzheimer's disease, and both cerebral blood flow and its responses during neural activation are reduced before Alzheimer's disease symptoms onset. One hypothetical explanation is that capillary dysfunction reduces oxygen extraction efficacy. This study compares the morphology and hemodynamics of the microvasculature in the somatosensory cortex of 18-month-old APPSWE/PS1ΔE9 (transgenic [Tg]) mice and wild-type (WT) littermates. In particular, the extent to which their capillary transit times homogenize during functional activation was measured and compared. Capillary length density was similar in both groups but capillary blood flow during rest was lower in the Tg mice, indicating that cortical oxygen availability is reduced. The capillary hemodynamic response to functional activation was larger, and lasted longer in Tg mice than in WT mice. The homogenization of capillary transit times during functional activation, which we previously demonstrated in young mice, was absent in the Tg mice. This study demonstrates that both neurovascular coupling and capillary function are profoundly disturbed in aged Tg and WT mice.
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195
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Jang H, Huang S, Hammer DX, Wang L, Rafi H, Ye M, Welle CG, Fisher JAN. Alterations in neurovascular coupling following acute traumatic brain injury. NEUROPHOTONICS 2017; 4:045007. [PMID: 29296629 PMCID: PMC5741992 DOI: 10.1117/1.nph.4.4.045007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 11/28/2017] [Indexed: 06/07/2023]
Abstract
Following acute traumatic brain injury (TBI), timely transport to a hospital can significantly improve the prognosis for recovery. There is, however, a dearth of quantitative biomarkers for brain injury that can be rapidly acquired and interpreted in active, field environments in which TBIs are frequently incurred. We explored potential functional indicators for TBI that can be noninvasively obtained through portable detection modalities, namely optical and electrophysiological approaches. By combining diffuse correlation spectroscopy with colocalized electrophysiological measurements in a mouse model of TBI, we observed concomitant alterations in sensory-evoked cerebral blood flow (CBF) and electrical potentials following controlled cortical impact. Injury acutely reduced the peak amplitude of both electrophysiological and CBF responses, which mostly recovered to baseline values within 30 min, and intertrial variability for these parameters was also acutely altered. Notably, the postinjury dynamics of the CBF overshoot and undershoot amplitudes differed significantly; whereas the amplitude of the initial peak of stimulus-evoked CBF recovered relatively rapidly, the ensuing undershoot did not appear to recover within 30 min of injury. Additionally, acute injury induced apparent low-frequency oscillatory behavior in CBF ([Formula: see text]). Histological assessment indicated that these physiological alterations were not associated with any major, persisting anatomical changes. Several time-domain features of the blood flow and electrophysiological responses showed strong correlations in recovery kinetics. Overall, our results reveal an array of stereotyped, injury-induced alterations in electrophysiological and hemodynamic responses that can be rapidly obtained using a combination of portable detection techniques.
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Affiliation(s)
- Hyounguk Jang
- New York Medical College, Department of Physiology, Valhalla, New York, United States
- U.S. Food and Drug Administration, Division of Biomedical Physics, Silver Spring, Maryland, United States
| | - Stanley Huang
- U.S. Food and Drug Administration, Division of Biomedical Physics, Silver Spring, Maryland, United States
| | - Daniel X. Hammer
- U.S. Food and Drug Administration, Division of Biomedical Physics, Silver Spring, Maryland, United States
| | - Lin Wang
- New York Medical College, Department of Physiology, Valhalla, New York, United States
| | - Harmain Rafi
- New York Medical College, Department of Physiology, Valhalla, New York, United States
| | - Meijun Ye
- U.S. Food and Drug Administration, Division of Biomedical Physics, Silver Spring, Maryland, United States
| | - Cristin G. Welle
- U.S. Food and Drug Administration, Division of Biomedical Physics, Silver Spring, Maryland, United States
- University of Colorado Denver, Departments of Neurosurgery and Bioengineering, Aurora, Colorado, United States
| | - Jonathan A. N. Fisher
- New York Medical College, Department of Physiology, Valhalla, New York, United States
- U.S. Food and Drug Administration, Division of Biomedical Physics, Silver Spring, Maryland, United States
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196
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Ma J, Ma Y, Dong B, Bandet MV, Shuaib A, Winship IR. Prevention of the collapse of pial collaterals by remote ischemic perconditioning during acute ischemic stroke. J Cereb Blood Flow Metab 2017; 37:3001-3014. [PMID: 27909265 PMCID: PMC5536804 DOI: 10.1177/0271678x16680636] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 09/23/2016] [Accepted: 10/30/2016] [Indexed: 02/05/2023]
Abstract
Collateral circulation is a key variable determining prognosis and response to recanalization therapy during acute ischemic stroke. Remote ischemic perconditioning (RIPerC) involves inducing peripheral ischemia (typically in the limbs) during stroke and may reduce perfusion deficits and brain damage due to cerebral ischemia. In this study, we directly investigated pial collateral flow augmentation due to RIPerC during distal middle cerebral artery occlusion (MCAo) in rats. Blood flow through pial collaterals between the anterior cerebral artery (ACA) and the MCA was assessed in male Sprague Dawley rats using in vivo laser speckle contrast imaging (LSCI) and two photon laser scanning microscopy (TPLSM) during distal MCAo. LSCI and TPLSM revealed that RIPerC augmented collateral flow into distal MCA segments. Notably, while control rats exhibited an initial dilation followed by a progressive narrowing of pial arterioles 60 to 150-min post-MCAo (constricting to 80-90% of post-MCAo peak diameter), this constriction was prevented or reversed by RIPerC (such that vessel diameters increased to 105-110% of post-MCAo, pre-RIPerC diameter). RIPerC significantly reduced early ischemic damage measured 6 h after stroke onset. Thus, prevention of collateral collapse via RIPerC is neuroprotective and may facilitate other protective or recanalization therapies by improving blood flow in penumbral tissue.
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Affiliation(s)
- Junqiang Ma
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
- The First Affiliated Hospital, Shantou University Medical College, Shantou, China
| | - Yonglie Ma
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
| | - Bin Dong
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
| | - Mischa V Bandet
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
| | - Ashfaq Shuaib
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
- Department of Medicine, Division of Neurology, University of Alberta, Edmonton, AB, Canada
| | - Ian R Winship
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
- Ian R Winship, 12-127 Clinical Sciences Building, Edmonton, AB T6G 2R3, Canada.
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197
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Pericytes as Inducers of Rapid, Matrix Metalloproteinase-9-Dependent Capillary Damage during Ischemia. J Neurosci 2017; 37:129-140. [PMID: 28053036 DOI: 10.1523/jneurosci.2891-16.2016] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 10/20/2016] [Accepted: 11/01/2016] [Indexed: 11/21/2022] Open
Abstract
Blood-brain barrier disruption (BBB) and release of toxic blood molecules into the brain contributes to neuronal injury during stroke and other cerebrovascular diseases. While pericytes are builders and custodians of the BBB in the normal brain, their impact on BBB integrity during ischemia remains unclear. We imaged pericyte-labeled transgenic mice with in vivo two-photon microscopy to examine the relationship between pericytes and blood plasma leakage during photothrombotic occlusion of cortical capillaries. Upon cessation of capillary flow, we observed that plasma leakage occurred with three times greater frequency in regions where pericyte somata adjoined the endothelium. Pericyte somata covered only 7% of the total capillary length in cortex, indicating that a disproportionate amount of leakage occurred from a small fraction of the capillary bed. Plasma leakage was preceded by rapid activation of matrix metalloproteinase (MMP) at pericyte somata, which was visualized at high resolution in vivo using a fluorescent probe for matrix metalloproteinase-2/9 activity, fluorescein isothiocyanate (FITC)-gelatin. Coinjection of an MMP-9 inhibitor, but not an MMP-2 inhibitor, reduced pericyte-associated FITC-gelatin fluorescence and plasma leakage. These results suggest that pericytes contribute to rapid and localized proteolytic degradation of the BBB during cerebral ischemia. SIGNIFICANCE STATEMENT Pericytes are a key component of the neurovascular unit and are essential for normal BBB function. However, during acute ischemia, we find that pericytes are involved in creating rapid and heterogeneous BBB disruption in the capillary bed. The mechanism by which pericytes contribute to BBB damage warrants further investigation, as it may yield new therapeutic targets for acute stroke injury and other neurological diseases involving capillary flow impairment.
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198
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Coles JA, Myburgh E, Brewer JM, McMenamin PG. Where are we? The anatomy of the murine cortical meninges revisited for intravital imaging, immunology, and clearance of waste from the brain. Prog Neurobiol 2017; 156:107-148. [PMID: 28552391 DOI: 10.1016/j.pneurobio.2017.05.002] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 04/25/2017] [Accepted: 05/08/2017] [Indexed: 12/15/2022]
Abstract
Rapid progress is being made in understanding the roles of the cerebral meninges in the maintenance of normal brain function, in immune surveillance, and as a site of disease. Most basic research on the meninges and the neural brain is now done on mice, major attractions being the availability of reporter mice with fluorescent cells, and of a huge range of antibodies useful for immunocytochemistry and the characterization of isolated cells. In addition, two-photon microscopy through the unperforated calvaria allows intravital imaging of the undisturbed meninges with sub-micron resolution. The anatomy of the dorsal meninges of the mouse (and, indeed, of all mammals) differs considerably from that shown in many published diagrams: over cortical convexities, the outer layer, the dura, is usually thicker than the inner layer, the leptomeninx, and both layers are richly vascularized and innervated, and communicate with the lymphatic system. A membrane barrier separates them and, in disease, inflammation can be localized to one layer or the other, so experimentalists must be able to identify the compartment they are studying. Here, we present current knowledge of the functional anatomy of the meninges, particularly as it appears in intravital imaging, and review their role as a gateway between the brain, blood, and lymphatics, drawing on information that is scattered among works on different pathologies.
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Affiliation(s)
- Jonathan A Coles
- Centre for Immunobiology, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, Sir Graeme Davis Building, University of Glasgow, Glasgow, G12 8TA, United Kingdom.
| | - Elmarie Myburgh
- Centre for Immunology and Infection Department of Biology, University of York, Wentworth Way, Heslington, York YO10 5DD, United Kingdom
| | - James M Brewer
- Centre for Immunobiology, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, Sir Graeme Davis Building, University of Glasgow, Glasgow, G12 8TA, United Kingdom
| | - Paul G McMenamin
- Department of Anatomy & Developmental Biology, School of Biomedical and Psychological Sciences and Monash Biomedical Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, 10 Chancellor's Walk, Clayton, Victoria, 3800, Australia
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199
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Kyweriga M, Sun J, Wang S, Kline R, Mohajerani MH. A Large Lateral Craniotomy Procedure for Mesoscale Wide-field Optical Imaging of Brain Activity. J Vis Exp 2017. [PMID: 28518107 DOI: 10.3791/52642] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The craniotomy is a commonly performed procedure to expose the brain for in vivo experiments. In mouse research, most labs utilize a small craniotomy, typically 3 mm x 3 mm. This protocol introduces a method for creating a substantially larger 7 mm x 6 mm cranial window exposing most of a cerebral hemisphere over the mouse temporal and parietal cortices (e.g., bregma 2.5 - 4.5 mm, lateral 0 - 6 mm). To perform this surgery, the head must be tilted approximately 30° and much of the temporal muscle must be retracted. Due to the large amount of bone removal, this procedure is intended only for acute experiments with the animal anesthetized throughout the surgery and experiment. The main advantage of this innovative large lateral cranial window is to provide simultaneous access to both medial and lateral areas of the cortex. This large unilateral cranial window can be used to study the neural dynamics between cells, as well as between different cortical areas by combining multi-electrode electrophysiological recordings, imaging of neuronal activity (e.g., intrinsic or extrinsic imaging), and optogenetic stimulation. Additionally, this large craniotomy also exposes a large area of cortical blood vessels, allowing for direct manipulation of the lateral cortical vasculature.
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Affiliation(s)
- Michael Kyweriga
- Canadian Center for Behavioural Neuroscience, University of Lethbridge
| | - Jianjun Sun
- Canadian Center for Behavioural Neuroscience, University of Lethbridge
| | - Sunny Wang
- Canadian Center for Behavioural Neuroscience, University of Lethbridge
| | - Richard Kline
- Canadian Center for Behavioural Neuroscience, University of Lethbridge
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200
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Benbenishty A, Segev-Amzaleg N, Shaashua L, Melamed R, Ben-Eliyahu S, Blinder P. Maintaining unperturbed cerebral blood flow is key in the study of brain metastasis and its interactions with stress and inflammatory responses. Brain Behav Immun 2017; 62:265-276. [PMID: 28219803 PMCID: PMC5420452 DOI: 10.1016/j.bbi.2017.02.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 02/08/2017] [Accepted: 02/16/2017] [Indexed: 12/15/2022] Open
Abstract
Blood-borne brain metastases are associated with poor prognosis, but little is known about the interplay between cerebral blood flow, surgical stress responses, and the metastatic process. The intra-carotid inoculation approach, traditionally used in animal studies, involves permanent occlusion of the common carotid artery (CCA). Herein we introduced a novel intra-carotid inoculation approach that avoids CCA ligation, namely - assisted external carotid artery inoculation (aECAi) - and compared it to the traditional approach in C57/BL6 mice, assessing cerebral blood flow; particle distribution; blood-brain barrier (BBB) integrity; stress, inflammatory and immune responses; and brain tumor retention and growth. Doppler flowmetry and two-photon imaging confirmed that only in the traditional approach regional and capillary cerebral blood flux were significantly reduced. Corticosterone and plasma IL-6 levels were higher in the traditional approach, splenic numbers of NK, CD3+, granulocytes, and dendritic cells were lower, and many of these indices were more profoundly affected by surgical stress in the traditional approach. BBB integrity was unaffected. Administration of spherical beads indicated that CCA ligation significantly limited brain distribution of injected particles, and inoculation of D122-LLC syngeneic tumor cells resulted in 10-fold lower brain tumor-cell retention in the traditional approach. Last, while most of the injected tumor cells were arrested in extra-cranial head areas, our method improved targeting of brain-tissue by 7-fold. This head versus brain distribution difference, commonly overlooked, cannot be detected using in vivo bioluminescent imaging. Overall, it is crucial to maintain unperturbed cerebral blood flow while studying brain metastasis and interactions with stress and inflammatory responses.
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Affiliation(s)
- Amit Benbenishty
- Sagol School of Neuroscience, Tel Aviv University, Israel; Neurobiology Department, George S. Wise Faculty of Life Sciences, Tel Aviv University, Israel; School of Psychological Sciences, Tel Aviv University, Israel
| | - Niva Segev-Amzaleg
- Neurobiology Department, George S. Wise Faculty of Life Sciences, Tel Aviv University, Israel
| | - Lee Shaashua
- School of Psychological Sciences, Tel Aviv University, Israel
| | - Rivka Melamed
- School of Psychological Sciences, Tel Aviv University, Israel
| | - Shamgar Ben-Eliyahu
- Sagol School of Neuroscience, Tel Aviv University, Israel; School of Psychological Sciences, Tel Aviv University, Israel
| | - Pablo Blinder
- Sagol School of Neuroscience, Tel Aviv University, Israel; Neurobiology Department, George S. Wise Faculty of Life Sciences, Tel Aviv University, Israel.
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