251
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Cornelius NR, Nishimura N, Suh M, Schwartz TH, Doerschuk PC. A mathematical model relating cortical oxygenated and deoxygenated hemoglobin flows and volumes to neural activity. J Neural Eng 2015; 12:046013. [PMID: 26045465 DOI: 10.1088/1741-2560/12/4/046013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To describe a toolkit of components for mathematical models of the relationship between cortical neural activity and space-resolved and time-resolved flows and volumes of oxygenated and deoxygenated hemoglobin motivated by optical intrinsic signal imaging (OISI). APPROACH Both blood flow and blood volume and both oxygenated and deoxygenated hemoglobin and their interconversion are accounted for. Flow and volume are described by including analogies to both resistive and capacitive electrical circuit elements. Oxygenated and deoxygenated hemoglobin and their interconversion are described by generalization of Kirchhoff's laws based on well-mixed compartments. MAIN RESULTS Mathematical models built from this toolkit are able to reproduce experimental single-stimulus OISI results that are described in papers from other research groups and are able to describe the response to multiple-stimuli experiments as a sublinear superposition of responses to the individual stimuli. SIGNIFICANCE The same assembly of tools from the toolkit but with different parameter values is able to describe effects that are considered distinctive, such as the presence or absence of an initial decrease in oxygenated hemoglobin concentration, indicating that the differences might be due to unique parameter values in a subject rather than different fundamental mechanisms.
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Affiliation(s)
- Nathan R Cornelius
- Department of Biomedical Engineering, Weill Hall, Cornell University, Ithaca, NY 14853, USA
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252
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Huo BX, Greene SE, Drew PJ. Venous cerebral blood volume increase during voluntary locomotion reflects cardiovascular changes. Neuroimage 2015; 118:301-12. [PMID: 26057593 DOI: 10.1016/j.neuroimage.2015.06.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 05/05/2015] [Accepted: 06/03/2015] [Indexed: 01/08/2023] Open
Abstract
Understanding how changes in the cardiovascular system contribute to cerebral blood flow (CBF) and volume (CBV) increases is critical for interpreting hemodynamic signals. Here we investigated how systemic cardiovascular changes affect the cortical hemodynamic response during voluntary locomotion. In the mouse, voluntary locomotion drives an increase in cortical CBF and arterial CBV that is localized to the forelimb/hindlimb representation in the somatosensory cortex, as well as a diffuse venous CBV increase. To determine if the heart rate increases that accompany locomotion contribute to locomotion-induced CBV and CBF increases, we occluded heart rate increases with the muscarinic cholinergic receptor antagonist glycopyrrolate, and reduced heart rate with the β1-adrenergic receptor antagonist atenolol. We quantified the effects of these cardiovascular manipulations on CBV and CBF dynamics by comparing the hemodynamic response functions (HRF) to locomotion across these conditions. Neither the CBF HRF nor the arterial component of the CBV HRF was significantly affected by pharmacological disruption of the heart rate. In contrast, the amplitude and spatial extent of the venous component of the CBV HRF were decreased by atenolol. These results suggest that the increase in venous CBV during locomotion was partially driven by peripheral cardiovascular changes, whereas CBF and arterial CBV increases associated with locomotion reflect central processes.
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Affiliation(s)
- Bing-Xing Huo
- Center for Neural Engineering Department of Engineering Science and Mechanics
| | - Stephanie E Greene
- Center for Neural Engineering Department of Engineering Science and Mechanics
| | - Patrick J Drew
- Center for Neural Engineering Department of Engineering Science and Mechanics; Department of Neurosurgery Pennsylvania State University, University Park, PA 16802, USA.
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253
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Tsai PS, Mateo C, Field JJ, Schaffer CB, Anderson ME, Kleinfeld D. Ultra-large field-of-view two-photon microscopy. OPTICS EXPRESS 2015; 23:13833-47. [PMID: 26072755 PMCID: PMC4523368 DOI: 10.1364/oe.23.013833] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 05/09/2015] [Accepted: 05/11/2015] [Indexed: 05/18/2023]
Abstract
We present a two-photon microscope that images the full extent of murine cortex with an objective-limited spatial resolution across an 8 mm by 10 mm field. The lateral resolution is approximately 1 µm and the maximum scan speed is 5 mm/ms. The scan pathway employs large diameter compound lenses to minimize aberrations and performs near theoretical limits. We demonstrate the special utility of the microscope by recording resting-state vasomotion across both hemispheres of the murine brain through a transcranial window and by imaging histological sections without the need to stitch.
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Affiliation(s)
- Philbert S. Tsai
- Department of Physics, University of California at San Diego, La Jolla, California, USA
| | - Celine Mateo
- Department of Physics, University of California at San Diego, La Jolla, California, USA
| | - Jeffrey J. Field
- Department of Electrical & Computer Engineering, Colorado State University, Fort Collins, Colorado, USA
| | - Chris B. Schaffer
- Department of Biomedical Engineering, Cornell University, Ithaca, New York, USA
| | - Matthew E. Anderson
- Department of Physics, San Diego State University, San Diego, California, USA
| | - David Kleinfeld
- Department of Physics, University of California at San Diego, La Jolla, California, USA
- Section of Neurobiology, University of California, La Jolla, California, USA
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254
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Wang H, Hong LJ, Huang JY, Jiang Q, Tao RR, Tan C, Lu NN, Wang CK, Ahmed MM, Lu YM, Liu ZR, Shi WX, Lai EY, Wilcox CS, Han F. P2RX7 sensitizes Mac-1/ICAM-1-dependent leukocyte-endothelial adhesion and promotes neurovascular injury during septic encephalopathy. Cell Res 2015; 25:674-90. [PMID: 25998681 PMCID: PMC4456628 DOI: 10.1038/cr.2015.61] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Revised: 02/10/2015] [Accepted: 03/12/2015] [Indexed: 12/15/2022] Open
Abstract
Septic encephalopathy (SE) is a critical factor determining sepsis mortality. Vascular inflammation is known to be involved in SE, but the molecular events that lead to the development of encephalopathy remain unclear. Using time-lapse in vivo two-photon laser scanning microscopy, we provide the first direct evidence that cecal ligation and puncture in septic mice induces microglial trafficking to sites adjacent to leukocyte adhesion on inflamed cerebral microvessels. Our data further demonstrate that septic injury increased the chemokine CXCL1 level in brain endothelial cells by activating endothelial P2RX7 and eventually enhanced the binding of Mac-1 (CD11b/CD18)-expressing leukocytes to endothelial ICAM-1. In turn, leukocyte adhesion upregulated endothelial CX3CL1, thereby triggering microglia trafficking to the injured site. The sepsis-induced increase in endothelial CX3CL1 was abolished in CD18 hypomorphic mutant mice. Inhibition of the P2RX7 pathway not only decreased endothelial ICAM-1 expression and leukocyte adhesion but also prevented microglia overactivation, reduced brain injury, and consequently doubled the early survival of septic mice. These results demonstrate the role of the P2RX7 pathway in linking neurovascular inflammation to brain damage in vivo and provide a rationale for targeting endothelial P2RX7 for neurovascular protection during SE.
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Affiliation(s)
- Huan Wang
- 1] Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China [2] Key Laboratory of Carbohydrate and Lipid Metabolism Research, College of Life Science and Technology, Dalian University, Dalian, Liaoning 116622, China
| | - Ling-Juan Hong
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Ji-Yun Huang
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Quan Jiang
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Rong-Rong Tao
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Chao Tan
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Nan-Nan Lu
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Cheng-Kun Wang
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Muhammad M Ahmed
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Ying-Mei Lu
- School of Medicine, Zhejiang University City College, Hangzhou, Zhejiang 310015, China
| | - Zhi-Rong Liu
- Department of Neurology, Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, Zhejiang 310009, China
| | - Wei-Xing Shi
- Department of Basic Sciences, Loma Linda University Health Schools of Medicine, Pharmacy, and Behavioral Health, Loma Linda, CA 92350, USA
| | - En-Yin Lai
- Department of Physiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Christopher S Wilcox
- Hypertension, Kidney, and Vascular Research Center, Georgetown University Medical Center, Washington DC 20007, USA
| | - Feng Han
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
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255
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Tang P, Zhang Y, Chen C, Ji X, Ju F, Liu X, Gan WB, He Z, Zhang S, Li W, Zhang L. In vivo two-photon imaging of axonal dieback, blood flow, and calcium influx with methylprednisolone therapy after spinal cord injury. Sci Rep 2015; 5:9691. [PMID: 25989524 PMCID: PMC4437044 DOI: 10.1038/srep09691] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 03/17/2015] [Indexed: 12/30/2022] Open
Abstract
Severe spinal cord injury (SCI) can cause neurological dysfunction and paralysis. However, the early dynamic changes of neurons and their surrounding environment after SCI are poorly understood. Although methylprednisolone (MP) is currently the standard therapeutic agent for treating SCI, its efficacy remains controversial. The purpose of this project was to investigate the early dynamic changes and MP's efficacy on axonal damage, blood flow, and calcium influx into axons in a mouse SCI model. YFP H-line and Thy1-GCaMP transgenic mice were used in this study. Two-photon microscopy was used for imaging of axonal dieback, blood flow, and calcium influx post-injury. We found that MP treatment attenuated progressive damage of axons, increased blood flow, and reduced calcium influx post-injury. Furthermore, microglia/macrophages accumulated in the lesion site after SCI and expressed the proinflammatory mediators iNOS, MCP-1 and IL-1β. MP treatment markedly inhibited the accumulation of microglia/macrophages and reduced the expression of the proinflammatory mediators. MP treatment also improved the recovery of behavioral function post-injury. These findings suggest that MP exerts a neuroprotective effect on SCI treatment by attenuating progressive damage of axons, increasing blood flow, reducing calcium influx, and inhibiting the accumulation of microglia/macrophages after SCI.
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Affiliation(s)
- Peifu Tang
- Department of Orthopedics, the General Hospital of Chinese People's Liberation Army, Beijing, China, 100853
| | - Yiling Zhang
- 1] Department of Orthopedics, the General Hospital of Chinese People's Liberation Army, Beijing, China, 100853 [2] Key Laboratory of Chemical Genomics, Shenzhen Graduate School, Peking University, Shenzhen, China, 518055
| | - Chao Chen
- 1] Department of Orthopedics, the General Hospital of Chinese People's Liberation Army, Beijing, China, 100853 [2] Key Laboratory of Chemical Genomics, Shenzhen Graduate School, Peking University, Shenzhen, China, 518055
| | - Xinran Ji
- Department of Orthopedics, the General Hospital of Chinese People's Liberation Army, Beijing, China, 100853
| | - Furong Ju
- School of Life Sciences, Lanzhou University, Lanzhou, China, 73000
| | - Xingyu Liu
- Beijing YouAn Hospital, Capital Medical University, Beijing, China, 100069
| | - Wen-Biao Gan
- 1] Key Laboratory of Chemical Genomics, Shenzhen Graduate School, Peking University, Shenzhen, China, 518055 [2] Skirball Institute, Department of Neuroscience and Physiology, New York University School of Medicine, New York, USA, 10016
| | - Zhigang He
- F.M. Kirby Program in Neuroscience, Children's Hospital Boston, Harvard Medical School, Boston, Massachusetts, USA, 02115
| | - Shengxiang Zhang
- School of Life Sciences, Lanzhou University, Lanzhou, China, 73000
| | - Wei Li
- Key Laboratory of Chemical Genomics, Shenzhen Graduate School, Peking University, Shenzhen, China, 518055
| | - Lihai Zhang
- Department of Orthopedics, the General Hospital of Chinese People's Liberation Army, Beijing, China, 100853
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256
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Shirey MJ, Smith JB, Kudlik DE, Huo BX, Greene SE, Drew PJ. Brief anesthesia, but not voluntary locomotion, significantly alters cortical temperature. J Neurophysiol 2015; 114:309-22. [PMID: 25972579 DOI: 10.1152/jn.00046.2015] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 05/11/2015] [Indexed: 11/22/2022] Open
Abstract
Changes in brain temperature can alter electrical properties of neurons and cause changes in behavior. However, it is not well understood how behaviors, like locomotion, or experimental manipulations, like anesthesia, alter brain temperature. We implanted thermocouples in sensorimotor cortex of mice to understand how cortical temperature was affected by locomotion, as well as by brief and prolonged anesthesia. Voluntary locomotion induced small (∼ 0.1 °C) but reliable increases in cortical temperature that could be described using a linear convolution model. In contrast, brief (90-s) exposure to isoflurane anesthesia depressed cortical temperature by ∼ 2 °C, which lasted for up to 30 min after the cessation of anesthesia. Cortical temperature decreases were not accompanied by a concomitant decrease in the γ-band local field potential power, multiunit firing rate, or locomotion behavior, which all returned to baseline within a few minutes after the cessation of anesthesia. In anesthetized animals where core body temperature was kept constant, cortical temperature was still > 1 °C lower than in the awake animal. Thermocouples implanted in the subcortex showed similar temperature changes under anesthesia, suggesting these responses occur throughout the brain. Two-photon microscopy of individual blood vessel dynamics following brief isoflurane exposure revealed a large increase in vessel diameter that ceased before the brain temperature significantly decreased, indicating cerebral heat loss was not due to increased cerebral blood vessel dilation. These data should be considered in experimental designs recording in anesthetized preparations, computational models relating temperature and neural activity, and awake-behaving methods that require brief anesthesia before experimental procedures.
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Affiliation(s)
- Michael J Shirey
- Center for Neural Engineering, Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania
| | - Jared B Smith
- Center for Neural Engineering, Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania;
| | - D'Anne E Kudlik
- Center for Neural Engineering, Bioengineering Graduate Program, Pennsylvania State University, University Park, Pennsylvania; and
| | - Bing-Xing Huo
- Center for Neural Engineering, Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania
| | - Stephanie E Greene
- Center for Neural Engineering, Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania
| | - Patrick J Drew
- Center for Neural Engineering, Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania; Department of Neurosurgery, Pennsylvania State University, University Park, Pennsylvania
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257
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Yao J, Wang L, Yang JM, Maslov KI, Wong TTW, Li L, Huang CH, Zou J, Wang LV. High-speed label-free functional photoacoustic microscopy of mouse brain in action. Nat Methods 2015; 12:407-10. [PMID: 25822799 PMCID: PMC4428901 DOI: 10.1038/nmeth.3336] [Citation(s) in RCA: 402] [Impact Index Per Article: 44.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 02/20/2015] [Indexed: 12/20/2022]
Abstract
We present fast functional photoacoustic microscopy (PAM) for three-dimensional high-resolution, high-speed imaging of the mouse brain, complementary to other imaging modalities. We implemented a single-wavelength pulse-width-based method with a one-dimensional imaging rate of 100 kHz to image blood oxygenation with capillary-level resolution. We applied PAM to image the vascular morphology, blood oxygenation, blood flow and oxygen metabolism in both resting and stimulated states in the mouse brain.
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Affiliation(s)
- Junjie Yao
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Lidai Wang
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Joon-Mo Yang
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Konstantin I Maslov
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Terence T W Wong
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Lei Li
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Chih-Hsien Huang
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas, USA
| | - Jun Zou
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas, USA
| | - Lihong V Wang
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
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258
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Park K, You J, Du C, Pan Y. Cranial window implantation on mouse cortex to study microvascular change induced by cocaine. Quant Imaging Med Surg 2015; 5:97-107. [PMID: 25694959 DOI: 10.3978/j.issn.2223-4292.2014.11.31] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 10/31/2014] [Indexed: 11/14/2022]
Abstract
Cocaine-induced stroke is among the most serious medical complications associated with cocaine's abuse. However, the extent to which chronic cocaine may induce silent microischemia predisposing the cerebral tissue to neurotoxicity has not been investigated; in part, because of limitations of current neuroimaging tools, that is, lack of high spatiotemporal resolution and sensitivity to simultaneously measure cerebral blood flow (CBF) in vessels of different calibers quantitatively and over a large field of view (FOV). Optical coherence tomography (OCT) technique allows us to image three dimensional (3D) cerebrovascular network (including artery, vein, and capillary), and provides high resolution angiography of the cerebral vasculature and quantitative CBF velocity (CBFv) within the individual vessels in the network. In order to monitor the neurovascular changes from an in vivo brain along with the chronic cocaine exposure, we have developed an approach of implanting a cranial window on mouse brain to achieve long-term cortical imaging. The cranial window was implanted on sensorimotor cortex area in two animal groups, i.e., control group [saline treatment, ~0.1 cc/10 g/day, intraperitoneal injection (i.p.)] and chronic cocaine group (cocaine treatment, 30 mg/kg/day i.p.). After implantation, the cortex of individual animal was periodically imaged by OCT and stereoscope to provide angiography and quantitative CBFv of the cerebral vascular network, as well as the surface imaging of the brain. We have observed vascular hemodynamic changes (i.e., CBFv changes) induced by the cranial preparation in both animal groups, including the inflammatory response of brain shortly after the surgery (i.e., <5 days) followed by wound-healing process (i.e., >5 days) in the brain. Importantly, by comparing with the control animals, the surgical-related vascular physiology changes in the cortex can be calibrated, so that the cocaine-induced hemodynamic changes in the neurovasculature can be determined in the cocaine animals. Our results demonstrate that this methodology can be used to explore the neurovascular functional changes induced by the brain diseases such as drug addiction.
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Affiliation(s)
- Kicheon Park
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| | - Jiang You
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| | - Congwu Du
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| | - Yingtian Pan
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
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259
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Tran CHT, Gordon GR. Acute two-photon imaging of the neurovascular unit in the cortex of active mice. Front Cell Neurosci 2015; 9:11. [PMID: 25698926 PMCID: PMC4318346 DOI: 10.3389/fncel.2015.00011] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 01/09/2015] [Indexed: 12/31/2022] Open
Abstract
In vivo two-photon scanning fluorescence imaging is a powerful technique to observe physiological processes from the millimeter to the micron scale in the intact animal. In neuroscience research, a common approach is to install an acute cranial window and head bar to explore neocortical function under anesthesia before inflammation peaks from the surgery. However, there are few detailed acute protocols for head-restrained and fully awake animal imaging of the neurovascular unit during activity. This is because acutely performed awake experiments are typically untenable when the animal is naïve to the imaging apparatus. Here we detail a method that achieves acute, deep-tissue two-photon imaging of neocortical astrocytes and microvasculature in behaving mice. A week prior to experimentation, implantation of the head bar alone allows mice to train for head-immobilization on an easy-to-learn air-supported ball treadmill. Following just two brief familiarization sessions to the treadmill on separate days, an acute cranial window can subsequently be installed for immediate imaging. We demonstrate how running and whisking data can be captured simultaneously with two-photon fluorescence signals with acceptable movement artifacts during active motion. We also show possible applications of this technique by (1) monitoring dynamic changes to microvascular diameter and red blood cells in response to vibrissa sensory stimulation, (2) examining responses of the cerebral microcirculation to the systemic delivery of pharmacological agents using a tail artery cannula during awake imaging, and (3) measuring Ca(2+) signals from synthetic and genetically encoded Ca(2+) indicators in astrocytes. This method will facilitate acute two-photon fluorescence imaging in awake, active mice and help link cellular events within the neurovascular unit to behavior.
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Affiliation(s)
- Cam Ha T Tran
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary Calgary, AB, Canada
| | - Grant R Gordon
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary Calgary, AB, Canada
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260
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Atry F, Frye S, Richner TJ, Brodnick SK, Soehartono A, Williams J, Pashaie R. Monitoring Cerebral Hemodynamics Following Optogenetic Stimulation via Optical Coherence Tomography. IEEE Trans Biomed Eng 2015; 62:766-73. [DOI: 10.1109/tbme.2014.2364816] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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261
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Richner TJ, Baumgartner R, Brodnick SK, Azimipour M, Krugner-Higby LA, Eliceiri KW, Williams JC, Pashaie R. Patterned optogenetic modulation of neurovascular and metabolic signals. J Cereb Blood Flow Metab 2015; 35:140-7. [PMID: 25388678 PMCID: PMC4294407 DOI: 10.1038/jcbfm.2014.189] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 09/26/2014] [Accepted: 09/30/2014] [Indexed: 11/09/2022]
Abstract
The hemodynamic and metabolic response of the cortex depends spatially and temporally on the activity of multiple cell types. Optogenetics enables specific cell types to be modulated with high temporal precision and is therefore an emerging method for studying neurovascular and neurometabolic coupling. Going beyond temporal investigations, we developed a microprojection system to apply spatial photostimulus patterns in vivo. We monitored vascular and metabolic fluorescence signals after photostimulation in Thy1-channelrhodopsin-2 mice. Cerebral arteries increased in diameter rapidly after photostimulation, while nearby veins showed a slower smaller response. The amplitude of the arterial response was depended on the area of cortex stimulated. The fluorescence signal emitted at 450/100 nm and excited with ultraviolet is indicative of reduced nicotinamide adenine dinucleotide, an endogenous fluorescent enzyme involved in glycolysis and the citric acid cycle. This fluorescence signal decreased quickly and transiently after optogenetic stimulation, suggesting that glucose metabolism is tightly locked to optogenetic stimulation. To verify optogenetic stimulation of the cortex, we used a transparent substrate microelectrode array to map cortical potentials resulting from optogenetic stimulation. Spatial optogenetic stimulation is a new tool for studying neurovascular and neurometabolic coupling.
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Affiliation(s)
- Thomas J Richner
- Laboratory for Optical and Computational Instrumentation and Department of Biomedical Engineering, University of Wisconsin at Madison, Madison, Wisconsin, USA
| | - Ryan Baumgartner
- Department of Electrical Engineering and Computer Science, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Sarah K Brodnick
- Laboratory for Optical and Computational Instrumentation and Department of Biomedical Engineering, University of Wisconsin at Madison, Madison, Wisconsin, USA
| | - Mehdi Azimipour
- Department of Electrical Engineering and Computer Science, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Lisa A Krugner-Higby
- Laboratory for Optical and Computational Instrumentation and Department of Biomedical Engineering, University of Wisconsin at Madison, Madison, Wisconsin, USA
| | - Kevin W Eliceiri
- Laboratory for Optical and Computational Instrumentation and Department of Biomedical Engineering, University of Wisconsin at Madison, Madison, Wisconsin, USA
| | - Justin C Williams
- Laboratory for Optical and Computational Instrumentation and Department of Biomedical Engineering, University of Wisconsin at Madison, Madison, Wisconsin, USA
| | - Ramin Pashaie
- Department of Electrical Engineering and Computer Science, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
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262
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Letourneur A, Chen V, Waterman G, Drew PJ. A method for longitudinal, transcranial imaging of blood flow and remodeling of the cerebral vasculature in postnatal mice. Physiol Rep 2014; 2:2/12/e12238. [PMID: 25524276 PMCID: PMC4332216 DOI: 10.14814/phy2.12238] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
In the weeks following birth, both the brain and the vascular network that supplies it undergo dramatic alteration. While studies of the postnatal evolution of the pial vasculature and blood flow through its vessels have been previously done histologically or acutely, here we describe a neonatal reinforced thin‐skull preparation for longitudinally imaging the development of the pial vasculature in mice using two‐photon laser scanning microscopy. Starting with mice as young as postnatal day 2 (P2), we are able to chronically image cortical areas >1 mm2, repeatedly for several consecutive days, allowing us to observe the remodeling of the pial arterial and venous networks. We used this method to measure blood velocity in individual vessels over multiple days, and show that blood flow through individual pial venules was correlated with subsequent diameter changes. This preparation allows the longitudinal imaging of the developing mammalian cerebral vascular network and its physiology. We developed a technique to longitudinally image blood vessels in the neonatal mouse cortex transcranially using two‐photon microscopy. The blood vessels on the surface of the brain undergo substantial pruning after birth. Blood flow through a vessel was correlated with the subsequent diameter change of the vessel.
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Affiliation(s)
- Annelise Letourneur
- Department of Engineering Science and Mechanics, Center for Neural Engineering, Pennsylvania State University, University Park, Pennsylvania CNRS, CEA, Université de Caen Basse-Normandie, UMR 6301 ISTCT, CERVOxy. GIP CYCERON, Caen, France
| | - Victoria Chen
- Department of Engineering Science and Mechanics, Center for Neural Engineering, Pennsylvania State University, University Park, Pennsylvania
| | - Gar Waterman
- Department of Engineering Science and Mechanics, Center for Neural Engineering, Pennsylvania State University, University Park, Pennsylvania
| | - Patrick J Drew
- Department of Engineering Science and Mechanics, Center for Neural Engineering, Pennsylvania State University, University Park, Pennsylvania Department of Neurosurgery, Pennsylvania State University, University Park, Pennsylvania
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263
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Lauer FM, Kaemmerer E, Meckel T. Single molecule microscopy in 3D cell cultures and tissues. Adv Drug Deliv Rev 2014; 79-80:79-94. [PMID: 25453259 DOI: 10.1016/j.addr.2014.10.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 09/20/2014] [Accepted: 10/03/2014] [Indexed: 12/19/2022]
Abstract
From the onset of the first microscopic visualization of single fluorescent molecules in living cells at the beginning of this century, to the present, almost routine application of single molecule microscopy, the method has well-proven its ability to contribute unmatched detailed insight into the heterogeneous and dynamic molecular world life is composed of. Except for investigations on bacteria and yeast, almost the entire story of success is based on studies on adherent mammalian 2D cell cultures. However, despite this continuous progress, the technique was not able to keep pace with the move of the cell biology community to adapt 3D cell culture models for basic research, regenerative medicine, or drug development and screening. In this review, we will summarize the progress, which only recently allowed for the application of single molecule microscopy to 3D cell systems and give an overview of the technical advances that led to it. While initially posing a challenge, we finally conclude that relevant 3D cell models will become an integral part of the on-going success of single molecule microscopy.
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Affiliation(s)
- Florian M Lauer
- Membrane Dynamics, Department of Biology, Technische Universität Darmstadt, Schnittspahnstrasse 3-5, 64287 Darmstadt, Germany
| | - Elke Kaemmerer
- Membrane Dynamics, Department of Biology, Technische Universität Darmstadt, Schnittspahnstrasse 3-5, 64287 Darmstadt, Germany; Institute of Health and Biomedical Innovation, Science and Engineering Faculty, Queensland University of Technology, 60 Musk Ave, Kelvin Grove, 4059 QLD, Brisbane, Australia
| | - Tobias Meckel
- Membrane Dynamics, Department of Biology, Technische Universität Darmstadt, Schnittspahnstrasse 3-5, 64287 Darmstadt, Germany.
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264
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Crowe SE, Ellis-Davies GCR. Longitudinal in vivo two-photon fluorescence imaging. J Comp Neurol 2014; 522:1708-27. [PMID: 24214350 DOI: 10.1002/cne.23502] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 10/15/2013] [Accepted: 10/15/2013] [Indexed: 12/29/2022]
Abstract
Fluorescence microscopy is an essential technique for the basic sciences, especially biomedical research. Since the invention of laser scanning confocal microscopy in the 1980s, which enabled imaging both fixed and living biological tissue with 3D precision, high-resolution fluorescence imaging has revolutionized biological research. Confocal microscopy, by its very nature, has one fundamental limitation. Due to the confocal pinhole, deep tissue fluorescence imaging is not practical. In contrast (no pun intended), two-photon fluorescence microscopy allows, in principle, the collection of all emitted photons from fluorophores in the imaged voxel, dramatically extending our ability to see deep into living tissue. Since the development of transgenic mice with genetically encoded fluorescent protein in neocortical cells in 2000, two-photon imaging has enabled the dynamics of individual synapses to be followed for up to 2 years. Since the initial landmark contributions to this field in 2002, the technique has been used to understand how neuronal structure are changed by experience, learning, and memory and various diseases. Here we provide a basic summary of the crucial elements that are required for such studies, and discuss many applications of longitudinal two-photon fluorescence microscopy that have appeared since 2002.
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Affiliation(s)
- Sarah E Crowe
- Department of Neuroscience, Mount Sinai School of Medicine, New York, NY, 10029
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265
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Sironi L, Bouzin M, Inverso D, D'Alfonso L, Pozzi P, Cotelli F, Guidotti LG, Iannacone M, Collini M, Chirico G. In vivo flow mapping in complex vessel networks by single image correlation. Sci Rep 2014; 4:7341. [PMID: 25475129 PMCID: PMC4256590 DOI: 10.1038/srep07341] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 11/17/2014] [Indexed: 01/10/2023] Open
Abstract
We describe a novel method (FLICS, FLow Image Correlation Spectroscopy) to extract flow speeds in complex vessel networks from a single raster-scanned optical xy-image, acquired in vivo by confocal or two-photon excitation microscopy. Fluorescent flowing objects produce diagonal lines in the raster-scanned image superimposed to static morphological details. The flow velocity is obtained by computing the Cross Correlation Function (CCF) of the intensity fluctuations detected in pairs of columns of the image. The analytical expression of the CCF has been derived by applying scanning fluorescence correlation concepts to drifting optically resolved objects and the theoretical framework has been validated in systems of increasing complexity. The power of the technique is revealed by its application to the intricate murine hepatic microcirculatory system where blood flow speed has been mapped simultaneously in several capillaries from a single xy-image and followed in time at high spatial and temporal resolution.
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Affiliation(s)
- Laura Sironi
- Università degli Studi di Milano-Bicocca, Physics Department, Piazza della Scienza 3, I-20126, Milan, Italy
| | - Margaux Bouzin
- Università degli Studi di Milano-Bicocca, Physics Department, Piazza della Scienza 3, I-20126, Milan, Italy
| | - Donato Inverso
- 1] Division of Immunology, Transplantation and Infectious Diseases, IRCCS San Raffaele Scientific Institute, I-20132, Milan, Italy [2] Vita-Salute San Raffaele University, I-20132, Milan, Italy
| | - Laura D'Alfonso
- Università degli Studi di Milano-Bicocca, Physics Department, Piazza della Scienza 3, I-20126, Milan, Italy
| | - Paolo Pozzi
- Università degli Studi di Milano-Bicocca, Physics Department, Piazza della Scienza 3, I-20126, Milan, Italy
| | - Franco Cotelli
- Università degli Studi di Milano, Department of Life Sciences, Via Celoria 26, I-20133, Milan, Italy
| | - Luca G Guidotti
- Division of Immunology, Transplantation and Infectious Diseases, IRCCS San Raffaele Scientific Institute, I-20132, Milan, Italy
| | - Matteo Iannacone
- 1] Division of Immunology, Transplantation and Infectious Diseases, IRCCS San Raffaele Scientific Institute, I-20132, Milan, Italy [2] Vita-Salute San Raffaele University, I-20132, Milan, Italy
| | - Maddalena Collini
- Università degli Studi di Milano-Bicocca, Physics Department, Piazza della Scienza 3, I-20126, Milan, Italy
| | - Giuseppe Chirico
- Università degli Studi di Milano-Bicocca, Physics Department, Piazza della Scienza 3, I-20126, Milan, Italy
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266
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Huo BX, Gao YR, Drew PJ. Quantitative separation of arterial and venous cerebral blood volume increases during voluntary locomotion. Neuroimage 2014; 105:369-79. [PMID: 25467301 DOI: 10.1016/j.neuroimage.2014.10.030] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 10/07/2014] [Accepted: 10/12/2014] [Indexed: 12/14/2022] Open
Abstract
Voluntary locomotion is accompanied by large increases in cortical activity and localized increases in cerebral blood volume (CBV). We sought to quantitatively determine the spatial and temporal dynamics of voluntary locomotion-evoked cerebral hemodynamic changes. We measured single vessel dilations using two-photon microscopy and cortex-wide changes in CBV-related signal using intrinsic optical signal (IOS) imaging in head-fixed mice freely locomoting on a spherical treadmill. During bouts of locomotion, arteries dilated rapidly, while veins distended slightly and recovered slowly. The dynamics of diameter changes of both vessel types could be captured using a simple linear convolution model. Using these single vessel measurements, we developed a novel analysis approach to separate out spatially and temporally distinct arterial and venous components of the location-specific hemodynamic response functions (HRF) for IOS. The HRF of each pixel of was well fit by a sum of a fast arterial and a slow venous component. The HRFs of pixels in the limb representations of somatosensory cortex had a large arterial contribution, while in the frontal cortex the arterial contribution to the HRF was negligible. The venous contribution was much less localized, and was substantial in the frontal cortex. The spatial pattern and amplitude of these HRFs in response to locomotion in the cortex were robust across imaging sessions. Separating the more localized arterial component from the diffuse venous signals will be useful for dealing with the dynamic signals generated by naturalistic stimuli.
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Affiliation(s)
- Bing-Xing Huo
- Center for Neural Engineering, Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA 16802, United States
| | - Yu-Rong Gao
- Center for Neural Engineering, Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA 16802, United States; Neuroscience Graduate Program, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, United States
| | - Patrick J Drew
- Center for Neural Engineering, Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA 16802, United States; Neuroscience Graduate Program, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, United States; Department of Neurosurgery, Pennsylvania State University, University Park, PA 16802, United States.
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267
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Fumagalli S, Ortolano F, De Simoni MG. A close look at brain dynamics: Cells and vessels seen by in vivo two-photon microscopy. Prog Neurobiol 2014; 121:36-54. [DOI: 10.1016/j.pneurobio.2014.06.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 06/17/2014] [Accepted: 06/29/2014] [Indexed: 01/11/2023]
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268
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Yeh C, Soetikno B, Hu S, Maslov KI, Wang LV. Microvascular quantification based on contour-scanning photoacoustic microscopy. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:96011. [PMID: 25223708 PMCID: PMC4164706 DOI: 10.1117/1.jbo.19.9.096011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 08/27/2014] [Indexed: 05/04/2023]
Abstract
Accurate quantification of microvasculature remains of interest in fundamental pathophysiological studies and clinical trials. Current photoacoustic microscopy can noninvasively quantify properties of the microvasculature, including vessel density and diameter, with a high spatial resolution. However, the depth range of focus (i.e., focal zone) of optical-resolution photoacoustic microscopy (OR-PAM) is often insufficient to encompass the depth variations of features of interest—such as blood vessels—due to uneven tissue surfaces. Thus, time-consuming image acquisitions at multiple different focal planes are required to maintain the region of interest in the focal zone. We have developed continuous three-dimensional motorized contour-scanning OR-PAM, which enables real-time adjustment of the focal plane to track the vessels’ profile. We have experimentally demonstrated that contour scanning improves the signal-to-noise ratio of conventional OR-PAM by as much as 41% and shortens the image acquisition time by 3.2 times. Moreover, contour-scanning OR-PAM more accurately quantifies vessel density and diameter, and has been applied to studying tumors with uneven surfaces.
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Affiliation(s)
- Chenghung Yeh
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, St. Louis, Missouri 63130, United States
| | - Brian Soetikno
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, St. Louis, Missouri 63130, United States
| | - Song Hu
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, St. Louis, Missouri 63130, United States
- University of Virginia, Department of Biomedical Engineering, PO Box 800759, Charlottesville, Virginia 22908, United States
| | - Konstantin I. Maslov
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, St. Louis, Missouri 63130, United States
| | - Lihong V. Wang
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, St. Louis, Missouri 63130, United States
- Address all correspondence to: Lihong V. Wang, E-mail:
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269
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Hong G, Diao S, Chang J, Antaris AL, Chen C, Zhang B, Zhao S, Atochin DN, Huang PL, Andreasson KI, Kuo CJ, Dai H. Through-skull fluorescence imaging of the brain in a new near-infrared window. NATURE PHOTONICS 2014; 8:723-730. [PMID: 27642366 PMCID: PMC5026222 DOI: 10.1038/nphoton.2014.166] [Citation(s) in RCA: 596] [Impact Index Per Article: 59.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 06/23/2014] [Indexed: 05/17/2023]
Abstract
To date, brain imaging has largely relied on X-ray computed tomography and magnetic resonance angiography with limited spatial resolution and long scanning times. Fluorescence-based brain imaging in the visible and traditional near-infrared regions (400-900 nm) is an alternative but currently requires craniotomy, cranial windows and skull thinning techniques, and the penetration depth is limited to 1-2 mm due to light scattering. Here, we report through-scalp and through-skull fluorescence imaging of mouse cerebral vasculature without craniotomy utilizing the intrinsic photoluminescence of single-walled carbon nanotubes in the 1.3-1.4 micrometre near-infrared window. Reduced photon scattering in this spectral region allows fluorescence imaging reaching a depth of >2 mm in mouse brain with sub-10 micrometre resolution. An imaging rate of ~5.3 frames/s allows for dynamic recording of blood perfusion in the cerebral vessels with sufficient temporal resolution, providing real-time assessment of blood flow anomaly in a mouse middle cerebral artery occlusion stroke model.
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Affiliation(s)
- Guosong Hong
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | - Shuo Diao
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | - Junlei Chang
- Division of Hematology, School of Medicine, Stanford University, Stanford, California 94305, USA
| | - Alexander L Antaris
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | - Changxin Chen
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | - Bo Zhang
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | - Su Zhao
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | - Dmitriy N Atochin
- Cardiovascular Research Center and Cardiology Division, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Paul L Huang
- Cardiovascular Research Center and Cardiology Division, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Katrin I Andreasson
- Department of Neurology and Neurological Sciences, Stanford University Medical Center, Stanford, California 94305, USA
| | - Calvin J Kuo
- Division of Hematology, School of Medicine, Stanford University, Stanford, California 94305, USA
| | - Hongjie Dai
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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270
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You J, Du C, Volkow ND, Pan Y. Optical coherence Doppler tomography for quantitative cerebral blood flow imaging. BIOMEDICAL OPTICS EXPRESS 2014; 5:3217-30. [PMID: 25401033 PMCID: PMC4230874 DOI: 10.1364/boe.5.003217] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 07/28/2014] [Accepted: 08/04/2014] [Indexed: 05/03/2023]
Abstract
Optical coherence Doppler tomography (ODT) is a promising neurotechnique that permits 3D imaging of the cerebral blood flow (CBF) network; however, quantitative CBF velocity (CBFv) imaging remains challenging. Here we present a simple phase summation method to enhance slow capillary flow detection sensitivity without sacrificing dynamic range for fast flow and vessel tracking to improve angle correction for absolute CBFv quantification. Flow phantom validation indicated that the CBFv quantification accuracy increased from 15% to 91% and the coefficient of variation (CV) decreased 9.3-fold; in vivo mouse brain validation showed that CV decreased 4.4-/10.8- fold for venular/arteriolar flows. ODT was able to identify cocaine-elicited microischemia and quantify CBFv disruption in branch vessels and capillaries that otherwise would have not been possible.
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Affiliation(s)
- Jiang You
- Department of Biomedical Engineering Stony Brook University, Stony Brook, NY 11794, USA
| | - Congwu Du
- Department of Biomedical Engineering Stony Brook University, Stony Brook, NY 11794, USA
| | - Nora D. Volkow
- National Institute on Drug Abuse, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yingtian Pan
- Department of Biomedical Engineering Stony Brook University, Stony Brook, NY 11794, USA
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271
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Guo L, Wong MS. Multiphoton excited fluorescent materials for frequency upconversion emission and fluorescent probes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:5400-5428. [PMID: 24981591 DOI: 10.1002/adma.201400084] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 04/17/2014] [Indexed: 06/03/2023]
Abstract
Recent progress in developing various strategies for exploiting efficient MPA fluorophores for two emerging technological MPA applications including frequency upconversion photoluminescence and lasing as well as 2PA fluorescence bioimaging and biosensing are presented. An intriguing application of MPA frequency-upconverted lasing offers opportunity for the fabrication of high-energy coherent light sources in the blue region which could create new advantages and breakthroughs in various laser-based applications. In addition, multiphoton excitation has led to considerable progress in the development of advanced diagnostic and therapeutic treatments; further advancement is anticipated with the emergence of various versatile 2PA fluorescence probes. It is widely appreciated that the two-photon excitation offers significant advantages for the biological fluorescence imaging and sensing which includes higher spatial resolution, less photobleaching and photodamage as well as deeper tissue penetration as compared to the one-photon excited microscopy. To be practically useful, the 2PA fluorescent probes for biological applications are required to have a site-specificity, a high fluorescence quantum yield, proper two-photon excitation and subsequent emission wavelengths, good photodecomposition stability, water solubility, and biocompatibility besides large 2PA action cross-sections.
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Affiliation(s)
- Lei Guo
- Institute of Molecular Functional Materials+, Department of Chemistry and Institute of Advanced Materials, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR, China
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272
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Martin C. Contributions and complexities from the use of in vivo animal models to improve understanding of human neuroimaging signals. Front Neurosci 2014; 8:211. [PMID: 25191214 PMCID: PMC4137227 DOI: 10.3389/fnins.2014.00211] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Accepted: 07/01/2014] [Indexed: 01/18/2023] Open
Abstract
Many of the major advances in our understanding of how functional brain imaging signals relate to neuronal activity over the previous two decades have arisen from physiological research studies involving experimental animal models. This approach has been successful partly because it provides opportunities to measure both the hemodynamic changes that underpin many human functional brain imaging techniques and the neuronal activity about which we wish to make inferences. Although research into the coupling of neuronal and hemodynamic responses using animal models has provided a general validation of the correspondence of neuroimaging signals to specific types of neuronal activity, it is also highlighting the key complexities and uncertainties in estimating neural signals from hemodynamic markers. This review will detail how research in animal models is contributing to our rapidly evolving understanding of what human neuroimaging techniques tell us about neuronal activity. It will highlight emerging issues in the interpretation of neuroimaging data that arise from in vivo research studies, for example spatial and temporal constraints to neuroimaging signal interpretation, or the effects of disease and modulatory neurotransmitters upon neurovascular coupling. We will also give critical consideration to the limitations and possible complexities of translating data acquired in the typical animals models used in this area to the arena of human fMRI. These include the commonplace use of anesthesia in animal research studies and the fact that many neuropsychological questions that are being actively explored in humans have limited homologs within current animal models for neuroimaging research. Finally we will highlighting approaches, both in experimental animals models (e.g. imaging in conscious, behaving animals) and human studies (e.g. combined fMRI-EEG), that mitigate against these challenges.
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Affiliation(s)
- Chris Martin
- Department of Psychology, The University of Sheffield Sheffield, UK
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273
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Aswendt M, Adamczak J, Tennstaedt A. A review of novel optical imaging strategies of the stroke pathology and stem cell therapy in stroke. Front Cell Neurosci 2014; 8:226. [PMID: 25177269 PMCID: PMC4132298 DOI: 10.3389/fncel.2014.00226] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 07/22/2014] [Indexed: 12/17/2022] Open
Abstract
Transplanted stem cells can induce and enhance functional recovery in experimental stroke. Invasive analysis has been extensively used to provide detailed cellular and molecular characterization of the stroke pathology and engrafted stem cells. But post mortem analysis is not appropriate to reveal the time scale of the dynamic interplay between the cell graft, the ischemic lesion and the endogenous repair mechanisms. This review describes non-invasive imaging techniques which have been developed to provide complementary in vivo information. Recent advances were made in analyzing simultaneously different aspects of the cell graft (e.g., number of cells, viability state, and cell fate), the ischemic lesion (e.g., blood-brain-barrier consistency, hypoxic, and necrotic areas) and the neuronal and vascular network. We focus on optical methods, which permit simple animal preparation, repetitive experimental conditions, relatively medium-cost instrumentation and are performed under mild anesthesia, thus nearly under physiological conditions. A selection of recent examples of optical intrinsic imaging, fluorescence imaging and bioluminescence imaging to characterize the stroke pathology and engrafted stem cells are discussed. Special attention is paid to novel optimal reporter genes/probes for genetic labeling and tracking of stem cells and appropriate transgenic animal models. Requirements, advantages and limitations of these imaging platforms are critically discussed and placed into the context of other non-invasive techniques, e.g., magnetic resonance imaging and positron emission tomography, which can be joined with optical imaging in multimodal approaches.
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Affiliation(s)
| | | | - Annette Tennstaedt
- In-vivo-NMR Laboratory, Max Planck Institute for Neurological Research, KölnGermany
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274
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Hammer DX, Lozzi A, Abliz E, Greenbaum N, Agrawal A, Krauthamer V, Welle CG. Longitudinal vascular dynamics following cranial window and electrode implantation measured with speckle variance optical coherence angiography. BIOMEDICAL OPTICS EXPRESS 2014; 5:2823-36. [PMID: 25136505 PMCID: PMC4133009 DOI: 10.1364/boe.5.002823] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 07/14/2014] [Accepted: 07/18/2014] [Indexed: 05/18/2023]
Abstract
Speckle variance optical coherence angiography (OCA) was used to characterize the vascular tissue response from craniotomy, window implantation, and electrode insertion in mouse motor cortex. We observed initial vasodilation ~40% greater than original diameter 2-3 days post-surgery (dps). After 4 weeks, dilation subsided in large vessels (>50 µm diameter) but persisted in smaller vessels (25-50 µm diameter). Neovascularization began 8-12 dps and vessel migration continued throughout the study. Vasodilation and neovascularization were primarily associated with craniotomy and window implantation rather than electrode insertion. Initial evidence of capillary re-mapping in the region surrounding the implanted electrode was manifest in OCA image dissimilarity. Further investigation, including higher resolution imaging, is required to validate the finding. Spontaneous lesions also occurred in many electrode animals, though the inception point appeared random and not directly associated with electrode insertion. OCA allows high resolution, label-free in vivo visualization of neurovascular tissue, which may help determine any biological contribution to chronic electrode signal degradation. Vascular and flow-based biomarkers can aid development of novel neural prostheses.
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275
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Urban A, Mace E, Brunner C, Heidmann M, Rossier J, Montaldo G. Chronic assessment of cerebral hemodynamics during rat forepaw electrical stimulation using functional ultrasound imaging. Neuroimage 2014; 101:138-49. [PMID: 25008960 DOI: 10.1016/j.neuroimage.2014.06.063] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 06/10/2014] [Accepted: 06/27/2014] [Indexed: 01/29/2023] Open
Abstract
Functional ultrasound imaging is a method recently developed to assess brain activity via hemodynamics in rodents. Doppler ultrasound signals allow the measurement of cerebral blood volume (CBV) and red blood cells' (RBCs') velocity in small vessels. However, this technique originally requires performing a large craniotomy that limits its use to acute experiments only. Moreover, a detailed description of the hemodynamic changes that underlie functional ultrasound imaging has not been described but is essential for a better interpretation of neuroimaging data. To overcome the limitation of the craniotomy, we developed a dedicated thinned skull surgery for chronic imaging. This procedure did not induce brain inflammation nor neuronal death as confirmed by immunostaining. We successfully acquired both high-resolution images of the microvasculature and functional movies of the brain hemodynamics on the same animal at 0, 2, and 7 days without loss of quality. Then, we investigated the spatiotemporal evolution of the CBV hemodynamic response function (HRF) in response to sensory-evoked electrical stimulus (1 mA) ranging from 1 (200 μs) to 25 pulses (5s). Our results indicate that CBV HRF parameters such as the peak amplitude, the time to peak, the full width at half-maximum and the spatial extent of the activated area increase with stimulus duration. Functional ultrasound imaging was sensitive enough to detect hemodynamic responses evoked by only a single pulse stimulus. We also observed that the RBC velocity during activation could be separated in two distinct speed ranges with the fastest velocities located in the upper part of the cortex and slower velocities in deeper layers. For the first time, functional ultrasound imaging demonstrates its potential to image brain activity chronically in small animals and offers new insights into the spatiotemporal evolution of cerebral hemodynamics.
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Affiliation(s)
- Alan Urban
- Université Paris Descartes Sorbonne Paris Cité, Centre de Psychiatrie et Neurosciences, INSERM S894, Centre Hospitalier Sainte-Anne, Paris, France.
| | - Emilie Mace
- 1A Allée des bois de Gagny, 93340 Le Raincy, France
| | - Clément Brunner
- Université Paris Descartes Sorbonne Paris Cité, Centre de Psychiatrie et Neurosciences, INSERM S894, Centre Hospitalier Sainte-Anne, Paris, France
| | - Marc Heidmann
- Université Paris Descartes Sorbonne Paris Cité, Centre de Psychiatrie et Neurosciences, INSERM S894, Centre Hospitalier Sainte-Anne, Paris, France
| | - Jean Rossier
- Université Paris Descartes Sorbonne Paris Cité, Centre de Psychiatrie et Neurosciences, INSERM S894, Centre Hospitalier Sainte-Anne, Paris, France
| | - Gabriel Montaldo
- Université Paris Descartes Sorbonne Paris Cité, Centre de Psychiatrie et Neurosciences, INSERM S894, Centre Hospitalier Sainte-Anne, Paris, France
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276
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Gao YR, Drew PJ. Determination of vessel cross-sectional area by thresholding in Radon space. J Cereb Blood Flow Metab 2014; 34:1180-7. [PMID: 24736890 PMCID: PMC4083381 DOI: 10.1038/jcbfm.2014.67] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Revised: 03/25/2014] [Accepted: 03/26/2014] [Indexed: 11/09/2022]
Abstract
The cross-sectional area of a blood vessel determines its resistance, and thus is a regulator of local blood flow. However, the cross-sections of penetrating vessels in the cortex can be non-circular, and dilation and constriction can change the shape of the vessels. We show that observed vessel shape changes can introduce large errors in flux calculations when using a single diameter measurement. Because of these shape changes, typical diameter measurement approaches, such as the full-width at half-maximum (FWHM) that depend on a single diameter axis will generate erroneous results, especially when calculating flux. Here, we present an automated method--thresholding in Radon space (TiRS)--for determining the cross-sectional area of a convex object, such as a penetrating vessel observed with two-photon laser scanning microscopy (2PLSM). The thresholded image is transformed back to image space and contiguous pixels are segmented. The TiRS method is analogous to taking the FWHM across multiple axes and is more robust to noise and shape changes than FWHM and thresholding methods. We demonstrate the superior precision of the TiRS method with in vivo 2PLSM measurements of vessel diameter.
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Affiliation(s)
- Yu-Rong Gao
- 1] Center for Neural Engineering, Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania, USA [2] Neuroscience Graduate Program, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Patrick J Drew
- 1] Center for Neural Engineering, Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania, USA [2] Neuroscience Graduate Program, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA [3] Department of Neurosurgery, Pennsylvania State University, University Park, Pennsylvania, USA
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277
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Abstract
After a century of false hopes, recent studies have placed the concept of diaschisis at the centre of the understanding of brain function. Originally, the term 'diaschisis' was coined by von Monakow in 1914 to describe the neurophysiological changes that occur distant to a focal brain lesion. In the following decades, this concept triggered widespread clinical interest in an attempt to describe symptoms and signs that the lesion could not fully explain. However, the first imaging studies, in the late 1970s, only partially confirmed the clinical significance of diaschisis. Focal cortical areas of diaschisis (i.e. focal diaschisis) contributed to the clinical deficits after subcortical but only rarely after cortical lesions. For this reason, the concept of diaschisis progressively disappeared from the mainstream of research in clinical neurosciences. Recent evidence has unexpectedly revitalized the notion. The development of new imaging techniques allows a better understanding of the complexity of brain organization. It is now possible to reliably investigate a new type of diaschisis defined as the changes of structural and functional connectivity between brain areas distant to the lesion (i.e. connectional diaschisis). As opposed to focal diaschisis, connectional diaschisis, focusing on determined networks, seems to relate more consistently to the clinical findings. This is particularly true after stroke in the motor and attentional networks. Furthermore, normalization of remote connectivity changes in these networks relates to a better recovery. In the future, to investigate the clinical role of diaschisis, a systematic approach has to be considered. First, emerging imaging and electrophysiological techniques should be used to precisely map and selectively model brain lesions in human and animals studies. Second, the concept of diaschisis must be applied to determine the impact of a focal lesion on new representations of the complexity of brain organization. As an example, the evaluation of remote changes in the structure of the connectome has so far mainly been tested by modelization of focal brain lesions. These changes could now be assessed in patients suffering from focal brain lesions (i.e. connectomal diaschisis). Finally, and of major significance, focal and non-focal neurophysiological changes distant to the lesion should be the target of therapeutic strategies. Neuromodulation using transcranial magnetic stimulation is one of the most promising techniques. It is when this last step will be successful that the concept of diaschisis will gain all the clinical respectability that could not be obtained in decades of research.
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Affiliation(s)
- Emmanuel Carrera
- 1 Department of Clinical Neurosciences, University Hospital, Geneva, Switzerland2 Department of Psychiatry, Madison, Wisconsin, USA
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278
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Dorand RD, Barkauskas DS, Evans TA, Petrosiute A, Huang AY. Comparison of intravital thinned skull and cranial window approaches to study CNS immunobiology in the mouse cortex. INTRAVITAL 2014; 3:e29728. [PMID: 25568834 PMCID: PMC4283137 DOI: 10.4161/intv.29728] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2014] [Revised: 06/06/2014] [Accepted: 06/25/2014] [Indexed: 01/11/2023]
Abstract
Fluorescent imaging coupled with high-resolution femto-second pulsed infrared lasers allows for interrogation of cellular interactions deeper in living tissues than ever imagined. Intra-vital imaging of the central nervous system (CNS) has provided insights into neuronal development, synaptic transmission, and even immune interactions. In this review we will discuss the two most common intravital approaches for studying the cerebral cortex in the live mouse brain for pre-clinical studies, the thinned skull and cranial window techniques, and focus on the advantages and drawbacks of each approach. In addition, we will discuss the use of neuronal physiologic parameters as determinants of successful surgical and imaging preparation.
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Affiliation(s)
- R Dixon Dorand
- Department of Pathology; Case Western Reserve University School of Medicine; Cleveland, Ohio USA
| | - Deborah S Barkauskas
- Department of Biomedical Engineering; Case Western Reserve University School of Medicine; Cleveland, Ohio USA
| | - Teresa A Evans
- Department of Neurosciences; Case Western Reserve University School of Medicine; Cleveland, Ohio USA
| | - Agne Petrosiute
- Department of Pediatrics; Case Western Reserve University School of Medicine; Cleveland, Ohio USA
| | - Alex Y Huang
- Department of Pathology; Case Western Reserve University School of Medicine; Cleveland, Ohio USA
- Department of Biomedical Engineering; Case Western Reserve University School of Medicine; Cleveland, Ohio USA
- Department of Pediatrics; Case Western Reserve University School of Medicine; Cleveland, Ohio USA
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279
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Desjardins M, Berti R, Lefebvre J, Dubeau S, Lesage F. Aging-related differences in cerebral capillary blood flow in anesthetized rats. Neurobiol Aging 2014; 35:1947-55. [PMID: 24612672 DOI: 10.1016/j.neurobiolaging.2014.01.136] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 01/09/2014] [Accepted: 01/27/2014] [Indexed: 11/30/2022]
Abstract
Age-related decreases in baseline cerebral blood flow have been measured with various imaging modalities, however, the contribution of capillary flow to this phenomenon remain to elucidate. This study used 2-photon laser scanning fluorescence microscopy to measure capillary diameter, red blood cell speed, and flux in individual capillaries in the sensory-motor cortex of 12 adult (3-month-old) and 12 old (24-month-old) male Long-Evans rats under isoflurane anesthesia. The average (± standard deviation) diameter and speed over 921 capillaries were 6.4 ± 1.4 μm and 1.3 ± 1.1 mm/s, respectively. Red blood cell speed and flux were significantly higher, by 48% and 15%, respectively, in old compared with young animals (p < 5%). The diameter also showed a similar tendency (7% higher, p = 5.7%). Furthermore, capillary hematocrit and density were significantly lower in the older group (p < 5%), by 32% and 20%, respectively.
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Affiliation(s)
- Michèle Desjardins
- Department de Génie Électrique, Institut de Génie Biomédical, École Polytechnique de Montréal, Montréal, Quebec, Canada; Montreal Heart Institute, Montréal, Quebec, Canada.
| | - Romain Berti
- Department de Génie Électrique, Institut de Génie Biomédical, École Polytechnique de Montréal, Montréal, Quebec, Canada; Montreal Heart Institute, Montréal, Quebec, Canada
| | - Joël Lefebvre
- Department de Génie Électrique, Institut de Génie Biomédical, École Polytechnique de Montréal, Montréal, Quebec, Canada; Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Simon Dubeau
- Department de Génie Électrique, Institut de Génie Biomédical, École Polytechnique de Montréal, Montréal, Quebec, Canada; Montreal Heart Institute, Montréal, Quebec, Canada
| | - Frédéric Lesage
- Department de Génie Électrique, Institut de Génie Biomédical, École Polytechnique de Montréal, Montréal, Quebec, Canada; Montreal Heart Institute, Montréal, Quebec, Canada; Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
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280
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Abstract
Stroke usually affects people with underlying medical conditions. In particular, diabetics are significantly more likely to have a stroke and the prognosis for recovery is poor. Because diabetes is associated with degenerative changes in the vasculature of many organs, we sought to determine how hyperglycemia affects blood flow dynamics after an ischemic stroke. Longitudinal in vivo two-photon imaging was used to track microvessels before and after photothrombotic stroke in a diabetic mouse model. Chronic hyperglycemia exacerbated acute (3-7 d) ischemia-induced increases in blood flow velocity, vessel lumen diameter, and red blood cell flux in peri-infarct regions. These changes in blood flow dynamics were most evident in superficial blood vessels within 500 μm from the infarct, rather than deeper or more distant cortical regions. Long-term imaging of diabetic mice not subjected to stroke indicated that these acute stroke-related changes in vascular function could not be attributed to complications from hyperglycemia alone. Treating diabetic mice with insulin immediately after stroke resulted in less severe alterations in blood flow within the first 7 d of recovery, but had more variable results at later time points. Analysis of microvessel branching patterns revealed that stroke led to a pruning of microvessels in peri-infarct cortex, with very few instances of sprouting. These results indicate that chronic hyperglycemia significantly affects the vascular response to ischemic stroke and that insulin only partially mitigates these changes. The combination of these acute and chronic alterations in blood flow dynamics could underlie diabetes-related deficits in cortical plasticity and stroke recovery.
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281
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Xue S, Gong H, Jiang T, Luo W, Meng Y, Liu Q, Chen S, Li A. Indian-ink perfusion based method for reconstructing continuous vascular networks in whole mouse brain. PLoS One 2014; 9:e88067. [PMID: 24498247 PMCID: PMC3907580 DOI: 10.1371/journal.pone.0088067] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 01/05/2014] [Indexed: 11/18/2022] Open
Abstract
The topology of the cerebral vasculature, which is the energy transport corridor of the brain, can be used to study cerebral circulatory pathways. Limited by the restrictions of the vascular markers and imaging methods, studies on cerebral vascular structure now mainly focus on either observation of the macro vessels in a whole brain or imaging of the micro vessels in a small region. Simultaneous vascular studies of arteries, veins and capillaries have not been achieved in the whole brain of mammals. Here, we have combined the improved gelatin-Indian ink vessel perfusion process with Micro-Optical Sectioning Tomography for imaging the vessel network of an entire mouse brain. With 17 days of work, an integral dataset for the entire cerebral vessels was acquired. The voxel resolution is 0.35×0.4×2.0 µm(3) for the whole brain. Besides the observations of fine and complex vascular networks in the reconstructed slices and entire brain views, a representative continuous vascular tracking has been demonstrated in the deep thalamus. This study provided an effective method for studying the entire macro and micro vascular networks of mouse brain simultaneously.
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Affiliation(s)
- Songchao Xue
- Britton Chance Center for Biomedical Photonics, Huazhong University of Science and Technology-Wuhan National Laboratory for Optoelectronics, Wuhan, China
- MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Hui Gong
- Britton Chance Center for Biomedical Photonics, Huazhong University of Science and Technology-Wuhan National Laboratory for Optoelectronics, Wuhan, China
- MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Tao Jiang
- Britton Chance Center for Biomedical Photonics, Huazhong University of Science and Technology-Wuhan National Laboratory for Optoelectronics, Wuhan, China
- MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Weihua Luo
- Britton Chance Center for Biomedical Photonics, Huazhong University of Science and Technology-Wuhan National Laboratory for Optoelectronics, Wuhan, China
- MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Yuanzheng Meng
- Britton Chance Center for Biomedical Photonics, Huazhong University of Science and Technology-Wuhan National Laboratory for Optoelectronics, Wuhan, China
- MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Qian Liu
- Britton Chance Center for Biomedical Photonics, Huazhong University of Science and Technology-Wuhan National Laboratory for Optoelectronics, Wuhan, China
- MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Shangbin Chen
- Britton Chance Center for Biomedical Photonics, Huazhong University of Science and Technology-Wuhan National Laboratory for Optoelectronics, Wuhan, China
- MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Anan Li
- Britton Chance Center for Biomedical Photonics, Huazhong University of Science and Technology-Wuhan National Laboratory for Optoelectronics, Wuhan, China
- MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
- * E-mail:
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282
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Desjardins M, Berti R, Pouliot P, Dubeau S, Lesage F. Multimodal study of the hemodynamic response to hypercapnia in anesthetized aged rats. Neurosci Lett 2014; 563:33-7. [PMID: 24480251 DOI: 10.1016/j.neulet.2014.01.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 01/13/2014] [Accepted: 01/17/2014] [Indexed: 10/25/2022]
Abstract
With aging, the brain undergoes changes in metabolism and perfusion, both of which influence the widely used blood-oxygenation-level-dependent (BOLD) MRI signal. To isolate the vascular effects associated with age, this study measured the response to a hypercapnic challenge using different imaging modalities in 19 young (3 months-old) and 13 old (24 months-old) Long-Evans rats. Intrinsic optical imaging was used to measure oxy (HbO), deoxy (HbR) and total (HbT) hemoglobin concentration changes, laser speckle for cerebral blood flow (CBF) changes, and MRI for the BOLD signal. Older rats had smaller HbO (41% smaller), HbT (50%) and CBF (34%) responses, but the temporal dynamics did not exhibit significant age differences. The ratio of CBV to CBF responses was also smaller in older adults, potentially indicating a change in the compliance of vessels.
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Affiliation(s)
- Michèle Desjardins
- Institut de Génie Biomédical, Dpt. de Génie Électrique, École Polytechnique de Montréal, C.P. 6079, succ. Centre-ville, Montréal, QC, H3C 3A7, Canada; Montreal Heart Institute, 5000 rue Bélanger, Montréal, QC, H1T 1C8, Canada.
| | - Romain Berti
- Institut de Génie Biomédical, Dpt. de Génie Électrique, École Polytechnique de Montréal, C.P. 6079, succ. Centre-ville, Montréal, QC, H3C 3A7, Canada; Montreal Heart Institute, 5000 rue Bélanger, Montréal, QC, H1T 1C8, Canada
| | - Philippe Pouliot
- Institut de Génie Biomédical, Dpt. de Génie Électrique, École Polytechnique de Montréal, C.P. 6079, succ. Centre-ville, Montréal, QC, H3C 3A7, Canada; Montreal Heart Institute, 5000 rue Bélanger, Montréal, QC, H1T 1C8, Canada
| | - Simon Dubeau
- Institut de Génie Biomédical, Dpt. de Génie Électrique, École Polytechnique de Montréal, C.P. 6079, succ. Centre-ville, Montréal, QC, H3C 3A7, Canada; Montreal Heart Institute, 5000 rue Bélanger, Montréal, QC, H1T 1C8, Canada
| | - Frédéric Lesage
- Institut de Génie Biomédical, Dpt. de Génie Électrique, École Polytechnique de Montréal, C.P. 6079, succ. Centre-ville, Montréal, QC, H3C 3A7, Canada; Montreal Heart Institute, 5000 rue Bélanger, Montréal, QC, H1T 1C8, Canada
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283
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Niklass S, Stoyanov S, Garz C, Bueche CZ, Mencl S, Reymann K, Heinze HJ, Carare RO, Kleinschnitz C, Schreiber S. Intravital imaging in spontaneously hypertensive stroke-prone rats-a pilot study. EXPERIMENTAL & TRANSLATIONAL STROKE MEDICINE 2014; 6:1. [PMID: 24461046 PMCID: PMC3996193 DOI: 10.1186/2040-7378-6-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 01/19/2014] [Indexed: 12/02/2022]
Abstract
Background There is growing evidence that endothelial failure and subsequent blood brain barrier (BBB) breakdown initiate cerebral small vessel disease (CSVD) pathology. In spontaneously hypertensive stroke-prone rats (SHRSP) endothelial damage is indicated by intraluminal accumulations of erythrocytes (erythrocyte thrombi) that are not observed with current magnetic resonance imaging techniques. Two-photon microscopy (2 PM) offers the potential for real-time direct detection of the small vasculature. Thus, within this pilot study we investigated the sensitivity of 2 PM to detect erythrocyte thrombi expressing initiating CSVD phenomena in vivo. Methods Eight SHRSP and 13 Wistar controls were used for in vivo imaging and subsequent histology with haematoxylin-eosin (HE). For 2 PM, cerebral blood vessels were labeled by fluorescent Dextran (70 kDa) applied intraorbitally. The correlation between vascular erythrocyte thrombi observed by 2 PM and HE-staining was assessed. Artificial surgical damage and parenchymal Dextran distribution were analyzed postmortem. Results Dextran was distributed within the small vessel walls and co-localized with IgG. Artificial surgical damage was comparable between SHRSP and Wistar controls and mainly affected the small vasculature. In fewer than 20% of animals there was correlation between erythrocyte thrombi as observed with 2 PM and histologically with HE. Conclusions Contrary to our initial expectations, there was little agreement between intravital 2 PM imaging and histology for the detection of erythrocyte thrombi. Two-photon microscopy is a valuable technique that complements but does not replace the value of conventional histology.
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Affiliation(s)
- Solveig Niklass
- Department of Neurology, Otto-von-Guericke-University, Leipziger Strasse 44, 39120 Magdeburg, Germany.
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284
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Choi WJ, Wang RK. Volumetric cutaneous microangiography of human skin in vivo by VCSEL swept-source optical coherence tomography. QUANTUM ELECTRONICS 2014; 44:740. [PMID: 25635163 PMCID: PMC4307845 DOI: 10.1070/qe2014v044n08abeh015542] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Three-dimensional (3D) assessment of cutaneous microcirculation in human skin is essential in the identification of disease states in skin or other organs. Few 3D imaging techniques have revealed the skin micro-vasculatures non-invasively and with sufficient imaging depth. Here, we demonstrate volumetric cutaneous microangiography of the human skin in vivo that utilizes a 1.3 µm high-speed swept-source optical coherence tomography (SS-OCT). The swept source is based on a MEMS tunable vertical cavity surface emission laser (VCSEL) that is advantageous in terms of long coherence length over 50 mm and 100 nm spectral bandwidth that enables the visualization of microstructures within a few mm from the skin surface. We show that skin microvasculature can be delineated in 3D SS-OCT images using ultrahigh-sensitive optical microangiography (UHS-OMAG) with a correlation mapping mask, providing a contrast enhanced blood perfusion map with capillary flow sensitivity. 3D microangiograms of a healthy human finger are shown with distinct cutaneous vessel architectures from different dermal layers and even within hypodermis. These findings suggest that the OCT microangiography could be a beneficial biomedical assay to assess cutaneous vascular functions in clinic.
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Affiliation(s)
| | - Ruikang K. Wang
- Address all correspondence to: Ruikang K. Wang, University of Washington, Department of Bioengineering, Seattle, Washington 98195; Tel: +1 206-616-5025; Fax: +1 206-685-3300;
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285
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Abstract
Laser speckle contrast imaging (LSCI) is a powerful tool capable of acquiring detailed maps of blood flow in arteries and veins on the cortical surface. Based on the blurring of laser speckle patterns by the motion of blood cells, LSCI can be combined with a variety of optical imaging preparations to acquire high-spatiotemporal resolution images of blood flow, and track changes in blood flow over time, using relatively simple instrumentation. Here, we describe methods for LSCI of cerebral blood flow via a thin skull imaging preparation in mice or rats. This preparation allows precise semiquantitative mapping of changes in blood flow over time using straightforward surgical protocols and equipment.
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Affiliation(s)
- Ian R Winship
- Centre for Neuroscience, University of Alberta, Edmonton, AB, Canada
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286
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Winship IR, Armitage GA, Ramakrishnan G, Dong B, Todd KG, Shuaib A. Augmenting collateral blood flow during ischemic stroke via transient aortic occlusion. J Cereb Blood Flow Metab 2014; 34:61-71. [PMID: 24045399 PMCID: PMC3887343 DOI: 10.1038/jcbfm.2013.162] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 08/20/2013] [Accepted: 08/23/2013] [Indexed: 11/09/2022]
Abstract
Collateral circulation provides an alternative route for blood flow to reach ischemic tissue during a stroke. Blood flow through the cerebral collaterals is a critical predictor of clinical prognosis after stroke and response to recanalization, but data on collateral dynamics and collateral therapeutics are lacking. Here, we investigate the efficacy of a novel approach to collateral blood flow augmentation to increase collateral circulation by optically recording blood flow in leptomeningeal collaterals in a clinically relevant model of ischemic stroke. Using high-resolution laser speckle contrast imaging (LSCI) during thromboembolic middle cerebral artery occlusion (MCAo), we demonstrate that transiently diverting blood flow from peripheral circulation towards the brain via intra-aortic catheter and balloon induces persistent increases in blood flow through anastomoses between the anterior and middle cerebral arteries. Increased collateral flow restores blood flow in the distal middle cerebral artery segments to baseline levels during aortic occlusion and persists for over 1 hour after removal of the aortic balloon. Given the importance of collateral circulation in predicting stroke outcome and response to treatment, and the potential of collateral flow augmentation as an adjuvant or stand-alone therapy for acute ischemic stroke, this data provide support for further development and translation of collateral therapeutics including transient aortic occlusion.
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Affiliation(s)
- Ian R Winship
- 1] Centre for Neuroscience, University of Alberta, Edmonton, Alberta, Canada [2] Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
| | - Glenn A Armitage
- 1] Centre for Neuroscience, University of Alberta, Edmonton, Alberta, Canada [2] Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
| | - Gomathi Ramakrishnan
- 1] Centre for Neuroscience, University of Alberta, Edmonton, Alberta, Canada [2] Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
| | - Bin Dong
- 1] Centre for Neuroscience, University of Alberta, Edmonton, Alberta, Canada [2] Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
| | - Kathryn G Todd
- 1] Centre for Neuroscience, University of Alberta, Edmonton, Alberta, Canada [2] Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
| | - Ashfaq Shuaib
- 1] Centre for Neuroscience, University of Alberta, Edmonton, Alberta, Canada [2] Department of Medicine, Division of Neurology, University of Alberta, Edmonton, Alberta, Canada
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287
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Bink DI, Ritz K, Aronica E, van der Weerd L, Daemen MJAP. Mouse models to study the effect of cardiovascular risk factors on brain structure and cognition. J Cereb Blood Flow Metab 2013; 33:1666-84. [PMID: 23963364 PMCID: PMC3824184 DOI: 10.1038/jcbfm.2013.140] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 06/24/2013] [Accepted: 07/16/2013] [Indexed: 12/13/2022]
Abstract
Recent clinical data indicates that hemodynamic changes caused by cardiovascular diseases such as atherosclerosis, heart failure, and hypertension affect cognition. Yet, the underlying mechanisms of the resulting vascular cognitive impairment (VCI) are poorly understood. One reason for the lack of mechanistic insights in VCI is that research in dementia primarily focused on Alzheimer's disease models. To fill in this gap, we critically reviewed the published data and various models of VCI. Typical findings in VCI include reduced cerebral perfusion, blood-brain barrier alterations, white matter lesions, and cognitive deficits, which have also been reported in different cardiovascular mouse models. However, the tests performed are incomplete and differ between models, hampering a direct comparison between models and studies. Nevertheless, from the currently available data we conclude that a few existing surgical animal models show the key features of vascular cognitive decline, with the bilateral common carotid artery stenosis hypoperfusion mouse model as the most promising model. The transverse aortic constriction and myocardial infarction models may be good alternatives, but these models are as yet less characterized regarding the possible cerebral changes. Mixed models could be used to study the combined effects of different cardiovascular diseases on the deterioration of cognition during aging.
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Affiliation(s)
- Diewertje I Bink
- Department of Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Katja Ritz
- Department of Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Eleonora Aronica
- Department of Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- SEIN—Stichting Epilepsie Instellingen Nederland, Heemstede, The Netherlands
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, The Netherlands
| | - Louise van der Weerd
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Mat JAP Daemen
- Department of Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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288
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Jeong DC, Tsai PS, Kleinfeld D. All-optical osteotomy to create windows for transcranial imaging in mice. OPTICS EXPRESS 2013; 21:23160-8. [PMID: 24104230 PMCID: PMC3971057 DOI: 10.1364/oe.21.023160] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 08/31/2013] [Accepted: 09/06/2013] [Indexed: 05/20/2023]
Abstract
Surgical procedures as a prelude to optical imaging are a rate-limiting step in experimental neuroscience. Towards automation of these procedures, we describe the use of nonlinear optical techniques to create a thinned skull window for transcranial imaging. Metrology by second harmonic generation was used to map the surfaces of the skull and define a cutting path. Plasma-mediated laser ablation was utilized to cut bone. Mice prepared with these techniques were used to image subsurface cortical vasculature and blood flow. The viability of the brain tissue was confirmed via histological analysis and supports the utility of solely optical techniques for osteotomy and potentially other surgical procedures.
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289
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Liang J, Zhou Y, Maslov KI, Wang LV. Cross-correlation-based transverse flow measurements using optical resolution photoacoustic microscopy with a digital micromirror device. JOURNAL OF BIOMEDICAL OPTICS 2013; 18:096004. [PMID: 24002191 PMCID: PMC3763964 DOI: 10.1117/1.jbo.18.9.096004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 08/09/2013] [Indexed: 05/06/2023]
Abstract
A cross-correlation-based method is proposed to quantitatively measure transverse flow velocity using optical resolution photoacoustic (PA) microscopy enhanced with a digital micromirror device (DMD). The DMD is used to alternately deliver two spatially separated laser beams to the target. Through cross-correlation between the slow-time PA profiles measured from the two beams, the speed and direction of transverse flow are simultaneously derived from the magnitude and sign of the time shift, respectively. Transverse flows in the range of 0.50 to 6.84 mm/s are accurately measured using an aqueous suspension of 10-μm-diameter microspheres, and the root-mean-squared measurement accuracy is quantified to be 0.22 mm/s. The flow measurements are independent of the particle size for flows in the velocity range of 0.55 to 6.49 mm/s, which was demonstrated experimentally using three different sizes of microspheres (diameters: 3, 6, and 10 μm). The measured flow velocity follows an expected parabolic distribution along the depth direction perpendicular to the flow. Both maximum and minimum measurable velocities are investigated for varied distances between the two beams and varied total time for one measurement. This technique shows an accuracy of 0.35 mm/s at 0.3-mm depth in scattering chicken breast, making it promising for measuring flow in biological tissue.
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Affiliation(s)
- Jinyang Liang
- Washington University in St. Louis, Optical Imaging Laboratory, Department of Biomedical Engineering, 1 Brookings Drive, St. Louis, Missouri 63130
| | - Yong Zhou
- Washington University in St. Louis, Optical Imaging Laboratory, Department of Biomedical Engineering, 1 Brookings Drive, St. Louis, Missouri 63130
| | - Konstantin I. Maslov
- Washington University in St. Louis, Optical Imaging Laboratory, Department of Biomedical Engineering, 1 Brookings Drive, St. Louis, Missouri 63130
| | - Lihong V. Wang
- Washington University in St. Louis, Optical Imaging Laboratory, Department of Biomedical Engineering, 1 Brookings Drive, St. Louis, Missouri 63130
- Address all correspondence to: Lihong V. Wang, Washington University in St. Louis, Optical Imaging Laboratory, Department of Biomedical Engineering, 1 Brookings Drive, St. Louis, Missouri 63130. Tel: 314-935-6152; Fax: 314-935-7448; E-mail:
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290
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Myburgh E, Coles JA, Ritchie R, Kennedy PGE, McLatchie AP, Rodgers J, Taylor MC, Barrett MP, Brewer JM, Mottram JC. In vivo imaging of trypanosome-brain interactions and development of a rapid screening test for drugs against CNS stage trypanosomiasis. PLoS Negl Trop Dis 2013; 7:e2384. [PMID: 23991236 PMCID: PMC3749981 DOI: 10.1371/journal.pntd.0002384] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 07/13/2013] [Indexed: 11/18/2022] Open
Abstract
HUMAN AFRICAN TRYPANOSOMIASIS (HAT) MANIFESTS IN TWO STAGES OF DISEASE: firstly, haemolymphatic, and secondly, an encephalitic phase involving the central nervous system (CNS). New drugs to treat the second-stage disease are urgently needed, yet testing of novel drug candidates is a slow process because the established animal model relies on detecting parasitemia in the blood as late as 180 days after treatment. To expedite compound screening, we have modified the GVR35 strain of Trypanosoma brucei brucei to express luciferase, and have monitored parasite distribution in infected mice following treatment with trypanocidal compounds using serial, non-invasive, bioluminescence imaging. Parasites were detected in the brains of infected mice following treatment with diminazene, a drug which cures stage 1 but not stage 2 disease. Intravital multi-photon microscopy revealed that trypanosomes enter the brain meninges as early as day 5 post-infection but can be killed by diminazene, whereas those that cross the blood-brain barrier and enter the parenchyma by day 21 survived treatment and later caused bloodstream recrudescence. In contrast, all bioluminescent parasites were permanently eliminated by treatment with melarsoprol and DB829, compounds known to cure stage 2 disease. We show that this use of imaging reduces by two thirds the time taken to assess drug efficacy and provides a dual-modal imaging platform for monitoring trypanosome infection in different areas of the brain.
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Affiliation(s)
- Elmarie Myburgh
- Wellcome Trust Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Jonathan A. Coles
- Wellcome Trust Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Ryan Ritchie
- Wellcome Trust Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Peter G. E. Kennedy
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Alex P. McLatchie
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Jean Rodgers
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Martin C. Taylor
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Michael P. Barrett
- Wellcome Trust Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- * E-mail:
| | - James M. Brewer
- Wellcome Trust Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Jeremy C. Mottram
- Wellcome Trust Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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291
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Nishimura N, Schaffer CB. Big effects from tiny vessels: imaging the impact of microvascular clots and hemorrhages on the brain. Stroke 2013; 44:S90-2. [PMID: 23709743 DOI: 10.1161/strokeaha.112.679621] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Nozomi Nishimura
- Department of Biomedical Engineering, Cornell University, Ithaca, NY 14850, USA.
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292
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Kazmi SMS, Salvaggio AJ, Estrada AD, Hemati MA, Shaydyuk NK, Roussakis E, Jones TA, Vinogradov SA, Dunn AK. Three-dimensional mapping of oxygen tension in cortical arterioles before and after occlusion. BIOMEDICAL OPTICS EXPRESS 2013; 4:1061-73. [PMID: 23847732 PMCID: PMC3704088 DOI: 10.1364/boe.4.001061] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 06/07/2013] [Accepted: 06/07/2013] [Indexed: 05/21/2023]
Abstract
Occlusions in single cortical microvessels lead to a reduction in oxygen supply, but this decrement has not been able to be quantified in three dimensions at the level of individual vessels using a single instrument. We demonstrate a combined optical system using two-photon phosphorescence lifetime and fluorescence microscopy (2PLM) to characterize the partial pressure of oxygen (pO2) in single descending cortical arterioles in the mouse brain before and after generating a targeted photothrombotic occlusion. Integrated real-time Laser Speckle Contrast Imaging (LSCI) provides wide-field perfusion maps that are used to monitor and guide the occlusion process while 2PLM maps changes in intravascular oxygen tension. We present the technique's utility in highlighting the effects of vascular networking on the residual intravascular oxygen tensions measured after occlusion in three dimensions.
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Affiliation(s)
- S. M. Shams Kazmi
- Department of Biomedical Engineering, The University of Texas at
Austin, 107 W. Dean Keeton C0800, Austin, Texas 78712, USA
| | - Anthony J. Salvaggio
- Department of Biomedical Engineering, The University of Texas at
Austin, 107 W. Dean Keeton C0800, Austin, Texas 78712, USA
| | - Arnold D. Estrada
- Department of Biomedical Engineering, The University of Texas at
Austin, 107 W. Dean Keeton C0800, Austin, Texas 78712, USA
| | - Michael A. Hemati
- Department of Biomedical Engineering, The University of Texas at
Austin, 107 W. Dean Keeton C0800, Austin, Texas 78712, USA
| | - Nazariy K. Shaydyuk
- Department of Biomedical Engineering, The University of Texas at
Austin, 107 W. Dean Keeton C0800, Austin, Texas 78712, USA
| | - Emannuel Roussakis
- Department of Biochemistry and Biophysics, Perelman School of
Medicine, University of Pennsylvania, 3700 Hamilton Walk, Philadelphia, Pennsylvania 19104,
USA
| | - Theresa A. Jones
- Department of Psychology, The University of Texas at Austin, 108 E.
Dean Keeton A8000, Austin, Texas 78712, USA
| | - Sergei A. Vinogradov
- Department of Biochemistry and Biophysics, Perelman School of
Medicine, University of Pennsylvania, 3700 Hamilton Walk, Philadelphia, Pennsylvania 19104,
USA
| | - Andrew K. Dunn
- Department of Biomedical Engineering, The University of Texas at
Austin, 107 W. Dean Keeton C0800, Austin, Texas 78712, USA
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293
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Gong P, Hua R, Zhang Y, Zhao H, Tang Z, Mei X, Zhang M, Cui J, Li C. Hypothermia-induced neuroprotection is associated with reduced mitochondrial membrane permeability in a swine model of cardiac arrest. J Cereb Blood Flow Metab 2013; 33:928-34. [PMID: 23486294 PMCID: PMC3677114 DOI: 10.1038/jcbfm.2013.33] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Increasing evidence has shown that mild hypothermia is neuroprotective for comatose patients resuscitated from cardiac arrest, but the mechanism of this protection is not fully understood. The aim of this study was to determine whether prolonged whole-body mild hypothermia inhibits mitochondrial membrane permeability (MMP) in the cerebral cortex after return of spontaneous circulation (ROSC). Thirty-seven inbred Chinese Wuzhishan minipigs were successfully resuscitated after 8 minutes of untreated ventricular fibrillation (VF) and underwent recovery under normothermic (NT) or prolonged whole-body mild hypothermic (HT; 33°C) conditions for 24 or 72 hours. Cerebral samples from the frontal cortex were collected at 24 and 72 hours after ROSC. Mitochondria were isolated by differential centrifugation. At 24 hours, relative to NT, HT was associated with reductions in opening of the mitochondrial permeability transition pore, release of pro-apoptotic substances from mitochondria, caspase 3 cleavage, apoptosis, and neurologic deficit scores, as well as increases in mitochondrial membrane potential and mitochondrial respiration. Together, these findings suggest that mild hypothermia inhibits ischemia-induced increases in MMP, which may provide neuroprotection against cerebral injury after cardiac arrest.
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Affiliation(s)
- Ping Gong
- Department of Emergency, First Hospital affiliated to Dalian Medical University, Dalian, China
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294
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Kazmi SMS, Parthasarthy AB, Song NE, Jones TA, Dunn AK. Chronic imaging of cortical blood flow using Multi-Exposure Speckle Imaging. J Cereb Blood Flow Metab 2013; 33:798-808. [PMID: 23571277 PMCID: PMC3677120 DOI: 10.1038/jcbfm.2013.57] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Chronic imaging of cerebral blood flow (CBF) is an important tool for investigating vascular remodeling after injury such as stroke. Although techniques such as Laser Speckle Contrast Imaging (LSCI) have emerged as valuable tools for imaging CBF in acute experiments, their utility for chronic measurements or cross-animal comparisons has been limited. Recently, an extension to LSCI called Multi-Exposure Speckle Imaging (MESI) was introduced that increases the quantitative accuracy of CBF images. In this paper, we show that estimates of chronic blood flow are better with MESI than with traditional LSCI. We evaluate the accuracy of the MESI flow estimates using red blood cell (RBC) photographic tracking as an absolute flow calibration in mice over several days. The flow measures computed using the MESI and LSCI techniques were found to be on average 10% and 24% deviant (n=9 mice), respectively, compared with RBC velocity changes. We also map CBF dynamics after photo-thrombosis of selected cortical microvasculature. Correlations of flow dynamics with RBC tracking were closer with MESI (r=0.88) than with LSCI (r=0.65) up to 2 weeks from baseline. With the increased quantitative accuracy, MESI can provide a platform for studying the efficacy of stroke therapies aimed at flow restoration.
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295
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Liao LD, Tsytsarev V, Delgado-Martínez I, Li ML, Erzurumlu R, Vipin A, Orellana J, Lin YR, Lai HY, Chen YY, Thakor NV. Neurovascular coupling: in vivo optical techniques for functional brain imaging. Biomed Eng Online 2013; 12:38. [PMID: 23631798 PMCID: PMC3655834 DOI: 10.1186/1475-925x-12-38] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Accepted: 03/25/2013] [Indexed: 01/21/2023] Open
Abstract
Optical imaging techniques reflect different biochemical processes in the brain, which is closely related with neural activity. Scientists and clinicians employ a variety of optical imaging technologies to visualize and study the relationship between neurons, glial cells and blood vessels. In this paper, we present an overview of the current optical approaches used for the in vivo imaging of neurovascular coupling events in small animal models. These techniques include 2-photon microscopy, laser speckle contrast imaging (LSCI), voltage-sensitive dye imaging (VSDi), functional photoacoustic microscopy (fPAM), functional near-infrared spectroscopy imaging (fNIRS) and multimodal imaging techniques. The basic principles of each technique are described in detail, followed by examples of current applications from cutting-edge studies of cerebral neurovascular coupling functions and metabolic. Moreover, we provide a glimpse of the possible ways in which these techniques might be translated to human studies for clinical investigations of pathophysiology and disease. In vivo optical imaging techniques continue to expand and evolve, allowing us to discover fundamental basis of neurovascular coupling roles in cerebral physiology and pathophysiology.
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Affiliation(s)
- Lun-De Liao
- Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, 28 Medical Drive, #05-COR, Singapore 117456, Singapore
| | - Vassiliy Tsytsarev
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 Penn street, HSF-2, Baltimore, MD 21201, USA
| | - Ignacio Delgado-Martínez
- Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, 28 Medical Drive, #05-COR, Singapore 117456, Singapore
| | - Meng-Lin Li
- Department of Electrical Engineering, National Tsing Hua University, No. 101, Sec. 2, Kuang-Fu Rd, Hsinchu 300, R.O.C, Taiwan
| | - Reha Erzurumlu
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 Penn street, HSF-2, Baltimore, MD 21201, USA
| | - Ashwati Vipin
- Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, 28 Medical Drive, #05-COR, Singapore 117456, Singapore
| | - Josue Orellana
- Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, 28 Medical Drive, #05-COR, Singapore 117456, Singapore
| | - Yan-Ren Lin
- Department of Emergency Medicine, Changhua Christian Hospital, 135 Nanshsiao Street, Changhua 500, R.O.C, Taiwan
| | - Hsin-Yi Lai
- Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan 333, R.O.C, Taiwan
| | - You-Yin Chen
- Department of Biomedical Engineering, National Yang Ming University, No.155, Sec.2, Linong St, Taipei 112, R.O.C, Taiwan
| | - Nitish V Thakor
- Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, 28 Medical Drive, #05-COR, Singapore 117456, Singapore
- Department of Biomedical Engineering, Johns Hopkins University, Traylor 701/720 Rutland Ave, Baltimore, MD 21205, USA
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296
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Mace E, Montaldo G, Osmanski BF, Cohen I, Fink M, Tanter M. Functional ultrasound imaging of the brain: theory and basic principles. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2013; 60:492-506. [PMID: 23475916 DOI: 10.1109/tuffc.2013.2592] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Hemodynamic changes in the brain are often used as surrogates of neuronal activity to infer the loci of brain activity. A major limitation of conventional Doppler ultrasound for the imaging of these changes is that it is not sensitive enough to detect the blood flow in small vessels where the major part of the hemodynamic response occurs. Here, we present a μDoppler ultrasound method able to detect and map the cerebral blood volume (CBV) over the entire brain with an important increase in sensitivity. This method is based on imaging the brain at an ultrafast frame rate (1 kHz) using compounded plane wave emissions. A theoretical model demonstrates that the gain in sensitivity of the μDoppler method is due to the combination of 1) the high signal-to-noise ratio of the gray scale images, resulting from the synthetic compounding of backscattered echoes; and 2) the extensive signal averaging enabled by the high temporal sampling of ultrafast frame rates. This μDoppler imaging is performed in vivo on trepanned rats without the use of contrast agents. The resulting images reveal detailed maps of the rat brain vascularization with an acquisition time as short as 320 ms per slice. This new method is the basis for a real-time functional ultrasound (fUS) imaging of the brain.
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Affiliation(s)
- Emilie Mace
- Institut Langevin, CNRS UMR7587, Inserm U979, Université Paris VII, Ecole Superieure de Physique et de Chimie Industrielles de Paris, Paris, France.
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297
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Radhakrishnan H, Srinivasan VJ. Compartment-resolved imaging of cortical functional hyperemia with OCT angiography. BIOMEDICAL OPTICS EXPRESS 2013; 4:1255-68. [PMID: 24009990 PMCID: PMC3756578 DOI: 10.1364/boe.4.001255] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Revised: 06/10/2013] [Accepted: 06/13/2013] [Indexed: 05/19/2023]
Abstract
Optical Coherence Tomography (OCT) angiography was applied to image functional hyperemia in different vascular compartments in the rat somatosensory cortex. Dynamic backscattering changes, indicative of changes in dynamic red blood cell (dRBC) content, were used to monitor the hemodynamic response. Three-dimensional movies depicting the microvascular response to neuronal activation were created for the first time. An increase in the attenuation coefficient during activation was identified, and a simple normalization procedure was proposed to correct for it. This procedure was applied to determine compartment-resolved backscattering changes caused by dRBC content changes during functional activation. Increases in dRBC content were observed in all vascular compartments (arterial, arteriolar, capillary, and venular), with the largest responses found in the arterial and arteriolar compartments. dRBC content increased with dilation in arteries but with barely detectable dilation in veins. dRBC content increased in capillaries without significant "all or none" capillary recruitment.
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Affiliation(s)
- Harsha Radhakrishnan
- Biomedical Engineering Department, University of California Davis, Davis, CA 95616, USA
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital/Harvard Medical School, Charlestown, MA 02129, USA
| | - Vivek J. Srinivasan
- Biomedical Engineering Department, University of California Davis, Davis, CA 95616, USA
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298
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Shih AY, Blinder P, Tsai PS, Friedman B, Stanley G, Lyden PD, Kleinfeld D. The smallest stroke: occlusion of one penetrating vessel leads to infarction and a cognitive deficit. Nat Neurosci 2013; 16:55-63. [PMID: 23242312 PMCID: PMC3952571 DOI: 10.1038/nn.3278] [Citation(s) in RCA: 230] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 11/15/2012] [Indexed: 11/09/2022]
Abstract
Microinfarctions are present in the aged and injured human brain. Their clinical relevance is controversial, with postulated sequelae ranging from cognitive sparing to vascular dementia. To address the consequences of microinfarcts, we used controlled optical methods to create occlusions of individual penetrating arterioles or venules in rat cortex. Single microinfarcts, targeted to encompass all or part of a cortical column, impaired performance in a macrovibrissa-based behavioral task. Furthermore, the targeting of multiple vessels resulted in tissue damage that coalesced across cortex, even though the intervening penetrating vessels were acutely patent. Post-occlusion administration of memantine, a glutamate receptor antagonist that reduces cognitive decline in Alzheimer's disease, ameliorated tissue damage and perceptual deficits. Collectively, these data imply that microinfarcts likely contribute to cognitive decline. Strategies that have received limited success in the treatment of ischemic injury, which include therapeutics against excitotoxicity, may be successful against the progressive nature of vascular dementia.
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Affiliation(s)
- Andy Y. Shih
- Department of Physics, University of California at San Diego, La Jolla, CA, USA
| | - Pablo Blinder
- Department of Physics, University of California at San Diego, La Jolla, CA, USA
| | - Philbert S. Tsai
- Department of Physics, University of California at San Diego, La Jolla, CA, USA
| | - Beth Friedman
- Department of Pharmacology, University of California at San Diego, La Jolla, CA, USA
| | - Geoffrey Stanley
- Department of Physics, University of California at San Diego, La Jolla, CA, USA
| | - Patrick D. Lyden
- Department of Neurology, Cedars-Sinai Hospital, Los Angeles, CA, USA
| | - David Kleinfeld
- Department of Physics, University of California at San Diego, La Jolla, CA, USA
- Section of Neurobiology, University of California at San Diego, La Jolla, CA, USA
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299
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Abstract
Targeted photothrombosis is a method to occlude individual arterioles and venules that lie on the surface of the cerebral cortex. It has been used to study collateral flow patterns within the pial vascular network following occlusion of single surface vessels (Schaffer et al., 2006; Blinder et al., 2010; Nguyen et al., 2011), as well as to generate localized ischemic strokes following occlusion of single penetrating vessels (Nishimura et al., 2007; Drew et al., 2010; Shih et al., 2013). The intravascular clot is formed by irradiation of a target vessel with a focused green laser after injection of a circulating photosensitizing agent, Rose Bengal (Watson et al., 1985). We briefly describe modifications of custom-designed and commercial two-photon imaging systems required to introduce a green laser for photothrombosis. We further provide instructions on how to occlude a single penetrating arteriole within the somatosensory cortex of an anesthetized mouse.
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Affiliation(s)
- Zachary J Taylor
- Department of Neurosciences, Medical University of South Carolina, Charleston, USA
| | - Andy Y Shih
- Department of Neurosciences, Medical University of South Carolina, Charleston, USA
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300
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Dufour S, Atchia Y, Gad R, Ringuette D, Sigal I, Levi O. Evaluation of laser speckle contrast imaging as an intrinsic method to monitor blood brain barrier integrity. BIOMEDICAL OPTICS EXPRESS 2013; 4:1856-75. [PMID: 24156049 PMCID: PMC3799651 DOI: 10.1364/boe.4.001856] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 06/07/2013] [Accepted: 07/23/2013] [Indexed: 05/19/2023]
Abstract
The integrity of the blood brain barrier (BBB) can contribute to the development of many brain disorders. We evaluate laser speckle contrast imaging (LSCI) as an intrinsic modality for monitoring BBB disruptions through simultaneous fluorescence and LSCI with vertical cavity surface emitting lasers (VCSELs). We demonstrated that drug-induced BBB opening was associated with a relative change of the arterial and venous blood velocities. Cross-sectional flow velocity ratio (veins/arteries) decreased significantly in rats treated with BBB-opening drugs, ≤0.81 of initial values.
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Affiliation(s)
- Suzie Dufour
- The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 King’s College Road, Toronto, ON M5S 3G4, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON M5S 3G9, Canada
| | - Yaaseen Atchia
- The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 King’s College Road, Toronto, ON M5S 3G4, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON M5S 3G9, Canada
| | - Raanan Gad
- The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 King’s College Road, Toronto, ON M5S 3G4, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON M5S 3G9, Canada
| | - Dene Ringuette
- The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 King’s College Road, Toronto, ON M5S 3G4, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON M5S 3G9, Canada
| | - Iliya Sigal
- The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 King’s College Road, Toronto, ON M5S 3G4, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON M5S 3G9, Canada
| | - Ofer Levi
- The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 King’s College Road, Toronto, ON M5S 3G4, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON M5S 3G9, Canada
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