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Cerri DH, Albaugh DL, Walton LR, Katz B, Wang TW, Chao THH, Zhang W, Nonneman RJ, Jiang J, Lee SH, Etkin A, Hall CN, Stuber GD, Shih YYI. Distinct neurochemical influences on fMRI response polarity in the striatum. Nat Commun 2024; 15:1916. [PMID: 38429266 PMCID: PMC10907631 DOI: 10.1038/s41467-024-46088-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 02/13/2024] [Indexed: 03/03/2024] Open
Abstract
The striatum, known as the input nucleus of the basal ganglia, is extensively studied for its diverse behavioral roles. However, the relationship between its neuronal and vascular activity, vital for interpreting functional magnetic resonance imaging (fMRI) signals, has not received comprehensive examination within the striatum. Here, we demonstrate that optogenetic stimulation of dorsal striatal neurons or their afferents from various cortical and subcortical regions induces negative striatal fMRI responses in rats, manifesting as vasoconstriction. These responses occur even with heightened striatal neuronal activity, confirmed by electrophysiology and fiber-photometry. In parallel, midbrain dopaminergic neuron optogenetic modulation, coupled with electrochemical measurements, establishes a link between striatal vasodilation and dopamine release. Intriguingly, in vivo intra-striatal pharmacological manipulations during optogenetic stimulation highlight a critical role of opioidergic signaling in generating striatal vasoconstriction. This observation is substantiated by detecting striatal vasoconstriction in brain slices after synthetic opioid application. In humans, manipulations aimed at increasing striatal neuronal activity likewise elicit negative striatal fMRI responses. Our results emphasize the necessity of considering vasoactive neurotransmission alongside neuronal activity when interpreting fMRI signal.
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Affiliation(s)
- Domenic H Cerri
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Daniel L Albaugh
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Lindsay R Walton
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Brittany Katz
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Tzu-Wen Wang
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Tzu-Hao Harry Chao
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Weiting Zhang
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Randal J Nonneman
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Jing Jiang
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, USA
- Department of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, IA, USA
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, IA, USA
- Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Sung-Ho Lee
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Amit Etkin
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, USA
- Alto Neuroscience, Los Altos, CA, USA
| | - Catherine N Hall
- Sussex Neuroscience, University of Sussex, Falmer, United Kingdom
- School of Psychology, University of Sussex, Falmer, United Kingdom
| | - Garret D Stuber
- Center for Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, WA, USA
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA
- Department of Pharmacology, University of Washington, Seattle, WA, USA
| | - Yen-Yu Ian Shih
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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2
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Han F, Liu X, Mailman RB, Huang X, Liu X. Resting-state global brain activity affects early β-amyloid accumulation in default mode network. Nat Commun 2023; 14:7788. [PMID: 38012153 PMCID: PMC10682457 DOI: 10.1038/s41467-023-43627-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 11/14/2023] [Indexed: 11/29/2023] Open
Abstract
It remains unclear why β-amyloid (Aβ) plaque, a hallmark pathology of Alzheimer's disease (AD), first accumulates cortically in the default mode network (DMN), years before AD diagnosis. Resting-state low-frequency ( < 0.1 Hz) global brain activity recently was linked to AD, presumably due to its role in glymphatic clearance. Here we show that the preferential Aβ accumulation in the DMN at the early stage of Aβ pathology was associated with the preferential reduction of global brain activity in the same regions. This can be partly explained by its failure to reach these regions as propagating waves. Together, these findings highlight the important role of resting-state global brain activity in early preferential Aβ deposition in the DMN.
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Affiliation(s)
- Feng Han
- Department of Biomedical Engineering, The Pennsylvania State University, State College, PA, USA
| | - Xufu Liu
- Department of Biomedical Engineering, The Pennsylvania State University, State College, PA, USA
| | - Richard B Mailman
- Departments of Neurology and Pharmacology, Translational Brain Research Center, Pennsylvania State University College of Medicine and Milton S. Hershey Medical Center, Hershey, PA, USA
| | - Xuemei Huang
- Departments of Neurology and Pharmacology, Translational Brain Research Center, Pennsylvania State University College of Medicine and Milton S. Hershey Medical Center, Hershey, PA, USA
- Departments of Radiology, Neurosurgery, and Kinesiology, Translational Brain Research Center, Pennsylvania State University and Milton S. Hershey Medical Center, Hershey, PA, USA
- Institute for Computational and Data Sciences, The Pennsylvania State University, State College, PA, USA
| | - Xiao Liu
- Department of Biomedical Engineering, The Pennsylvania State University, State College, PA, USA.
- Institute for Computational and Data Sciences, The Pennsylvania State University, State College, PA, USA.
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3
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Liu X. Decoupling Between Brain Activity and Cerebrospinal Fluid Movement in Neurological Disorders. J Magn Reson Imaging 2023:10.1002/jmri.29148. [PMID: 37991132 PMCID: PMC11109023 DOI: 10.1002/jmri.29148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 11/08/2023] [Accepted: 11/09/2023] [Indexed: 11/23/2023] Open
Abstract
Recent research has identified a link between the global mean signal of resting-state functional MRI (fMRI) and macro-scale cerebrospinal fluid movement, indicating the potential link between this resting-state dynamic and brain waste clearance. Consistent with this notion, the strength of this coupling has been associated with multiple neurodegenerative disease pathologies, especially the build-up of toxic proteins. This article aimed to review the latest advancements in this research area, emphasizing studies on spontaneous global brain activity that is tightly linked to the global mean resting-state fMRI signal, and aimed to discuss potential mechanisms through which this activity and associated physiological modulations might affect brain waste clearance. The available evidence supports the presence of a highly organized global brain activity that is linked to arousal and memory systems. This global brain dynamic, along with its associated physiological modulations, has the potential to influence brain waste clearance through multiple pathways through multiple pathways. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: Stage 3.
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Affiliation(s)
- Xiao Liu
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
- Institute for Computational and Data Sciences, The Pennsylvania State University, University Park, PA, 16802, USA
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4
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Han F, Lee J, Chen X, Ziontz J, Ward T, Landau SM, Baker SL, Harrison TM, Jagust WJ. Global brain activity and its coupling with cerebrospinal fluid flow is related to tau pathology. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.12.557492. [PMID: 37745434 PMCID: PMC10515801 DOI: 10.1101/2023.09.12.557492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Amyloid-β (Aβ) and tau deposition constitute Alzheimer's disease (AD) neuropathology. Cortical tau deposits first in the entorhinal cortex and hippocampus and then propagates to neocortex in an Aβ-dependent manner. Tau also tends to accumulate earlier in higher-order association cortex than in lower-order primary sensory-motor cortex. While previous research has examined the production and spread of tau, little attention has been paid to its clearance. Low-frequency (<0.1 Hz) global brain activity during the resting state is coupled with cerebrospinal fluid (CSF) flow and potentially reflects glymphatic clearance. Here we report that tau deposition in subjects with evaluated Aβ, accompanied by cortical thinning and cognitive decline, is strongly associated with decreased coupling between CSF flow and global brain activity. Substantial modulation of global brain activity is also manifested as propagating waves of brain activation between higher- and lower-order regions, resembling tau spreading. Together, the findings suggest an important role of resting-state global brain activity in AD tau pathology.
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Affiliation(s)
- Feng Han
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, USA
| | - JiaQie Lee
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, USA
| | - Xi Chen
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, USA
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Jacob Ziontz
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, USA
| | - Tyler Ward
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, USA
| | - Susan M Landau
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, USA
| | | | - Theresa M Harrison
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, USA
| | - William J Jagust
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, USA
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA
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5
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Blood-brain barrier leakage in Alzheimer's disease: From discovery to clinical relevance. Pharmacol Ther 2022; 234:108119. [PMID: 35108575 PMCID: PMC9107516 DOI: 10.1016/j.pharmthera.2022.108119] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/14/2022] [Accepted: 01/18/2022] [Indexed: 12/16/2022]
Abstract
Alzheimer's disease (AD) is the most common form of dementia. AD brain pathology starts decades before the onset of clinical symptoms. One early pathological hallmark is blood-brain barrier dysfunction characterized by barrier leakage and associated with cognitive decline. In this review, we summarize the existing literature on the extent and clinical relevance of barrier leakage in AD. First, we focus on AD animal models and their susceptibility to barrier leakage based on age and genetic background. Second, we re-examine barrier dysfunction in clinical and postmortem studies, summarize changes that lead to barrier leakage in patients and highlight the clinical relevance of barrier leakage in AD. Third, we summarize signaling mechanisms that link barrier leakage to neurodegeneration and cognitive decline in AD. Finally, we discuss clinical relevance and potential therapeutic strategies and provide future perspectives on investigating barrier leakage in AD. Identifying mechanistic steps underlying barrier leakage has the potential to unravel new targets that can be used to develop novel therapeutic strategies to repair barrier leakage and slow cognitive decline in AD and AD-related dementias.
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6
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Hatakeyama N, Unekawa M, Murata J, Tomita Y, Suzuki N, Nakahara J, Takuwa H, Kanno I, Matsui K, Tanaka KF, Masamoto K. Differential pial and penetrating arterial responses examined by optogenetic activation of astrocytes and neurons. J Cereb Blood Flow Metab 2021; 41:2676-2689. [PMID: 33899558 PMCID: PMC8504944 DOI: 10.1177/0271678x211010355] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A variety of brain cells participates in neurovascular coupling by transmitting and modulating vasoactive signals. The present study aimed to probe cell type-dependent cerebrovascular (i.e., pial and penetrating arterial) responses with optogenetics in the cortex of anesthetized mice. Two lines of the transgenic mice expressing a step function type of light-gated cation channel (channelrhodopsine-2; ChR2) in either cortical neurons (muscarinic acetylcholine receptors) or astrocytes (Mlc1-positive) were used in the experiments. Photo-activation of ChR2-expressing astrocytes resulted in a widespread increase in cerebral blood flow (CBF), extending to the nonstimulated periphery. In contrast, photo-activation of ChR2-expressing neurons led to a relatively localized increase in CBF. The differences in the spatial extent of the CBF responses are potentially explained by differences in the involvement of the vascular compartments. In vivo imaging of the cerebrovascular responses revealed that ChR2-expressing astrocyte activation led to the dilation of both pial and penetrating arteries, whereas ChR2-expressing neuron activation predominantly caused dilation of the penetrating arterioles. Pharmacological studies showed that cell type-specific signaling mechanisms participate in the optogenetically induced cerebrovascular responses. In conclusion, pial and penetrating arterial vasodilation were differentially evoked by ChR2-expressing astrocytes and neurons.
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Affiliation(s)
- Nao Hatakeyama
- Graduate School of Informatics and Engineering, University of Electro-Communications, Tokyo, Japan
| | - Miyuki Unekawa
- Department of Neurology, Keio University School of Medicine, Tokyo, Japan
| | - Juri Murata
- Graduate School of Informatics and Engineering, University of Electro-Communications, Tokyo, Japan
| | - Yutaka Tomita
- Department of Neurology, Keio University School of Medicine, Tokyo, Japan.,Tomita Hospital, Aichi, Japan
| | - Norihiro Suzuki
- Department of Neurology, Keio University School of Medicine, Tokyo, Japan.,Shonan Keiiku Hospital, Kanagawa, Japan
| | - Jin Nakahara
- Department of Neurology, Keio University School of Medicine, Tokyo, Japan
| | - Hiroyuki Takuwa
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, Chiba, Japan
| | - Iwao Kanno
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, Chiba, Japan
| | - Ko Matsui
- Super-Network Brain Physiology, Graduate School of Life Sciences, Tohoku University, Miyagi, Japan
| | - Kenji F Tanaka
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - Kazuto Masamoto
- Graduate School of Informatics and Engineering, University of Electro-Communications, Tokyo, Japan.,Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, Chiba, Japan.,Center for Neuroscience and Biomedical Engineering, University of Electro-Communications, Tokyo, Japan
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7
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Lee J, Stile CL, Bice AR, Rosenthal ZP, Yan P, Snyder AZ, Lee JM, Bauer AQ. Opposed hemodynamic responses following increased excitation and parvalbumin-based inhibition. J Cereb Blood Flow Metab 2021; 41:841-856. [PMID: 33736512 PMCID: PMC7983494 DOI: 10.1177/0271678x20930831] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 03/24/2020] [Accepted: 04/30/2020] [Indexed: 02/05/2023]
Abstract
Understanding cellular contributions to hemodynamic activity is essential for interpreting blood-based brain mapping signals. Optogenetic studies examining cell-specific influences on local hemodynamics have reported that excitatory activity results in cerebral perfusion and blood volume increase, while inhibitory activity contributes to both vasodilation and vasoconstriction. How specific subpopulations of interneurons regulate the brain's blood supply is less examined. Parvalbumin interneurons are the largest subpopulation of GABAergic neurons in the brain, critical for brain development, plasticity, and long-distance excitatory neurotransmission. Despite their essential role in brain function, the contribution of parvalbumin neurons to neurovascular coupling has been relatively unexamined. Using optical intrinsic signal imaging and laser speckle contrast imaging, we photostimulated awake and anesthetized transgenic mice expressing channelrhodopsin under a parvalbumin promoter. Increased parvalbumin activity reduced local oxygenation, cerebral blood volume, and cerebral blood flow. These "negative" hemodynamic responses were consistent within and across mice and reproducible across a broad range of photostimulus parameters. However, the sign and magnitude of the hemodynamic response resulting from increased parvalbumin activity depended on the type and level of anesthesia used. Opposed hemodynamic responses following increased excitation or parvalbumin-based inhibition suggest unique contributions from different cell populations to neurovascular coupling.
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Affiliation(s)
- Joonhyuk Lee
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Chloe L Stile
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Annie R Bice
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Zachary P Rosenthal
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Ping Yan
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Abraham Z Snyder
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Jin-Moo Lee
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
- Department of Biomedical Engineering, Washington University School of Medicine, St. Louis, MO, USA
| | - Adam Q Bauer
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
- Department of Biomedical Engineering, Washington University School of Medicine, St. Louis, MO, USA
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8
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Temeyer KB, Schlechte KG, Olafson PU, Drolet BS, Tidwell JP, Osbrink WLA, Showler AT, Gross AD, Pérez de León AA. Association of Salivary Cholinesterase With Arthropod Vectors of Disease. JOURNAL OF MEDICAL ENTOMOLOGY 2020; 57:1679-1685. [PMID: 32459332 DOI: 10.1093/jme/tjaa096] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Indexed: 06/11/2023]
Abstract
Acetylcholinesterase (AChE) was previously reported to be present in saliva of the southern cattle tick, Rhipicephalus (Boophilus) microplus (Canestrini), with proposed potential functions to 1) reduce acetylcholine toxicity during rapid engorgement, 2) modulate host immune responses, and 3) to influence pathogen transmission and establishment in the host. Potential modulation of host immune responses might include participation in salivary-assisted transmission and establishment of pathogens in the host as has been reported for a number of arthropod vector-borne diseases. If the hypothesis that tick salivary AChE may alter host immune responses is correct, we reasoned that similar cholinesterase activities might be present in saliva of additional arthropod vectors. Here, we report the presence of AChE-like activity in the saliva of southern cattle ticks, Rhipicephalus (Boophilus) microplus; the lone star tick, Amblyomma americanum (Linnaeus); Asian tiger mosquitoes, Aedes albopictus (Skuse); sand flies, Phlebotomus papatasi (Scopoli); and biting midges, Culicoides sonorensis Wirth and Jones. Salivary AChE-like activity was not detected for horn flies Haematobia irritans (L.), stable flies Stomoxys calcitrans (L.), and house flies Musca domestica L. Salivary cholinesterase (ChE) activities of arthropod vectors of disease-causing agents exhibited various Michaelis-Menten KM values that were each lower than the KM value of bovine serum AChE. A lower KM value is indicative of higher affinity for substrate and is consistent with a hypothesized role in localized depletion of host tissue acetylcholine potentially modulating host immune responses at the arthropod bite site that may favor ectoparasite blood-feeding and alter host defensive responses against pathogen transmission and establishment.
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Affiliation(s)
- Kevin B Temeyer
- Knipling-Bushland U.S. Livestock Insects Research Laboratory, USDA-ARS, Kerrville, TX
| | - Kristie G Schlechte
- Knipling-Bushland U.S. Livestock Insects Research Laboratory, USDA-ARS, Kerrville, TX
| | - Pia U Olafson
- Knipling-Bushland U.S. Livestock Insects Research Laboratory, USDA-ARS, Kerrville, TX
| | - Barbara S Drolet
- Arthropod-Borne Animal Diseases Research Unit, Center for Grain and Animal Health Research, USDA-ARS, Manhattan, KS
| | - Jason P Tidwell
- Cattle Fever Tick Research Laboratory, USDA-ARS, Edinburg, TX
| | - Weste L A Osbrink
- Knipling-Bushland U.S. Livestock Insects Research Laboratory, USDA-ARS, Kerrville, TX
| | - Allan T Showler
- Knipling-Bushland U.S. Livestock Insects Research Laboratory, USDA-ARS, Kerrville, TX
| | - Aaron D Gross
- Molecular Physiology and Toxicology Laboratory, Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA
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9
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Rane S, Koh N, Oakley J, Caso C, Zabetian CP, Cholerton B, Montine TJ, Grabowski T. Arterial spin labeling detects perfusion patterns related to motor symptoms in Parkinson's disease. Parkinsonism Relat Disord 2020; 76:21-28. [PMID: 32559629 PMCID: PMC7554132 DOI: 10.1016/j.parkreldis.2020.05.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 02/25/2020] [Accepted: 05/08/2020] [Indexed: 10/24/2022]
Abstract
INTRODUCTION Imaging neurovascular disturbances in Parkinson's disease (PD) is an excellent measure of disease severity. Indeed, a disease-specific regional pattern of abnormal metabolism has been identified using positron emission tomography. Only a handful of studies, however, have applied perfusion MRI to detect this disease pattern. Our goal was to replicate the evaluation of a PD-related perfusion pattern using scaled subprofile modeling/principal component analysis (SSM-PCA). METHODS We applied arterial spin labeling (ASL) MRI for this purpose. Uniquely, we assessed this pattern separately in PD individuals ON and OFF dopamine medications. We further compared the existence of these patterns and their strength in each individual with their Movement Disorder Society-Unified Parkinson's Disease Rating Scale motor (MDS-UPDRS) scores, cholinergic tone as indexed by short-term afferent inhibition (SAI), and other neuropsychiatric tests. RESULTS We observed a PD-related perfusion pattern that was similar to previous studies. The patterns were observed in both ON and OFF states but only the pattern in the OFF condition could significantly (AUC=0.72) differentiate between PD and healthy subjects. In the ON condition, PD subjects were similar to controls from a CBF standpoint (AUC=0.45). The OFF pattern prominently included the posterior cingulate, precentral region, precuneus, and the subcallosal cortex. Individual principal components from the ON and OFF states were strongly associated with MDS-UPDRS scores, SAI amplitude and latency. CONCLUSION Using ASL, our study identified patterns of abnormal perfusion in PD and were associated with disease symptoms.
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Affiliation(s)
- Swati Rane
- Integrated Brain Imaging Center, Radiology, University of Washington Medical Center, Seattle, WA, USA.
| | - Natalie Koh
- Integrated Brain Imaging Center, Radiology, University of Washington Medical Center, Seattle, WA, USA
| | - John Oakley
- Department of Neurology, University of Washington Medical Center, Seattle, WA, USA
| | - Christina Caso
- Integrated Brain Imaging Center, Radiology, University of Washington Medical Center, Seattle, WA, USA
| | - Cyrus P Zabetian
- Department of Neurology, University of Washington Medical Center, Seattle, WA, USA; Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA
| | - Brenna Cholerton
- Department of Pathology, Stanford University, Stanford, CA, 94305, USA
| | - Thomas J Montine
- Department of Pathology, Stanford University, Stanford, CA, 94305, USA
| | - Thomas Grabowski
- Integrated Brain Imaging Center, Radiology, University of Washington Medical Center, Seattle, WA, USA
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10
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Suzuki T, Waki H, Imai K, Hisajima T. Electroacupuncture of the Ophthalmic Branch of the Trigeminal Nerve: Effects on Prefrontal Cortex Blood Flow. Med Acupunct 2020; 32:143-149. [PMID: 32595821 DOI: 10.1089/acu.2019.1406] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Objective: The current authors observed enhanced cerebral blood flow (CBF) in the prefrontal cortex (PFC) in response to 100-Hz electroacupuncture (EA) stimulation of the ophthalmic branch of the trigeminal nerve. However, it is not yet clear if responsiveness to 100-Hz EA depends on stimulus intensity. This study examined the effects of stimulus strength on PFC CBF during 100-Hz EA of the ophthalmic branch of the trigeminal nerve. Materials and Methods: Twelve subjects underwent 3 acupuncture sessions: I, control, no stimulation; II, 0.1 mA EA; and III, 0.2 mA EA). Needles were inserted 1 cm lateral of the head median line; the anterior insertion point was on the front hairline and the posterior insertion point was ∼7 cm behind the hairline. Stimulation frequency was set to 100-Hz. PFC CBF was measured in terms of oxygenated, deoxygenated, and total hemoglobin (OxyHb, DeoxyHb, TotalHb, respectively), using 16-channel (Ch) near-infrared spectroscopy. Results: Stimulation of 0.2 mA was associated with significant elevation of OxyHb levels in the 0.1 mA condition in Chs 6, 10, and 12. Ch 2-6, 10, 12 signals were notably higher than in the control condition. Stimulation of 0.2 mA and 0.1 mA were associated with significant declines in DeoxyHb levels, compared to the control condition in Ch 4. Finally, 0.2 mA stimulation in Chs 12 and 13 was associated with significant elevation of TotalHb levels in the control condition. Conclusions: Using 0.2-mA stimulation, 100-Hz EA of the ophthalmic nerve enhances PFC CBF more strongly than 0.1-mA stimulation.
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Affiliation(s)
- Takuya Suzuki
- Graduate School of Health Sciences, Teikyo Heisei University, Toshima-ku, Tokyo, Japan
| | - Hideaki Waki
- Faculty of Health Care, Teikyo Heisei University, Toshima-ku, Tokyo, Japan.,Research Institute of Oriental Medicine, Toshima-ku, Tokyo, Japan
| | - Kenji Imai
- Faculty of Health Care, Teikyo Heisei University, Toshima-ku, Tokyo, Japan.,Research Institute of Oriental Medicine, Toshima-ku, Tokyo, Japan
| | - Tatsuya Hisajima
- Faculty of Health Care, Teikyo Heisei University, Toshima-ku, Tokyo, Japan.,Research Institute of Oriental Medicine, Toshima-ku, Tokyo, Japan
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11
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Blood pressure variability and outcome after acute intracerebral hemorrhage. J Neurol Sci 2020; 413:116766. [PMID: 32151850 DOI: 10.1016/j.jns.2020.116766] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 02/24/2020] [Accepted: 03/01/2020] [Indexed: 01/12/2023]
Abstract
Intracerebral hemorrhage (ICH) is life threatening neurologic event that results in significant rate of morbidity and mortality. Unfortunately, several randomized clinical trials aiming at limiting the hematoma expansion (HE) in the acute phase of ICH have not shown significant effects in improving the functional outcomes. Blood pressure variability (BPV) is common following ICH. High BPs have been associated with increased risk of bleeding and HE. Conversely, recurrent sudden decrease in BP promote perihematomal ischemia. However, it is still not clear weather BPV causes adverse prognosis following ICH or large ICHs cause fluctuations in BP. In the current review, we will discuss the mechanistic pathophysiology of BPV and the evidence regarding the role of BPV on the ICH outcomes.
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12
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Yu X, Ji C, Shao A. Neurovascular Unit Dysfunction and Neurodegenerative Disorders. Front Neurosci 2020; 14:334. [PMID: 32410936 PMCID: PMC7201055 DOI: 10.3389/fnins.2020.00334] [Citation(s) in RCA: 113] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 03/20/2020] [Indexed: 12/11/2022] Open
Abstract
The neurovascular unit (NVU), composed of vascular cells, glial cells, and neurons, is the minimal functional unit of the brain. The NVU maintains integrity of the blood–brain barrier (BBB) and regulates supply of the cerebral blood flow (CBF), both of which are keys to maintaining normal brain function. BBB dysfunction and a decreased CBF are early pathophysiological changes in neurodegenerative disorders, such as Alzheimer’s disease (AD), Parkinson’s disease (PD), and amyotrophic lateral sclerosis (ALS). In this review, we primarily focus on the NVU in AD as much research has been performed on the connection between NVU dysfunction and AD. We also discuss the role of NVU dysfunction in the pathophysiological mechanisms of PD and ALS. As most neurodegenerative diseases are difficult to treat, we discuss several potential drug targets that focus on the NVU that may inform novel vascular-targeted therapies for AD, PD, and ALS.
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Affiliation(s)
- Xing Yu
- Department of Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Caihong Ji
- Department of Neurology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Anwen Shao
- Department of Neurosurgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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13
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Vinciguerra L, Lanza G, Puglisi V, Fisicaro F, Pennisi M, Bella R, Cantone M. Update on the Neurobiology of Vascular Cognitive Impairment: From Lab to Clinic. Int J Mol Sci 2020; 21:E2977. [PMID: 32340195 PMCID: PMC7215552 DOI: 10.3390/ijms21082977] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 04/20/2020] [Accepted: 04/21/2020] [Indexed: 02/07/2023] Open
Abstract
In the last years, there has been a significant growth in the literature exploring the pathophysiology of vascular cognitive impairment (VCI). As an "umbrella term" encompassing any degree of vascular-related cognitive decline, VCI is deemed to be the most common cognitive disorder in the elderly, with a significant impact on social and healthcare expenses. Interestingly, some of the molecular, biochemical, and electrophysiological abnormalities detected in VCI seem to correlate with disease process and progression, eventually promoting an adaptive plasticity in some patients and a maladaptive, dysfunctional response in others. However, the exact relationships between vascular lesion, cognition, and neuroplasticity are not completely understood. Recent findings point out also the possibility to identify a panel of markers able to predict cognitive deterioration in the so-called "brain at risk" for vascular or mixed dementia. This will be of pivotal importance when designing trials of disease-modifying drugs or non-pharmacological approaches, including non-invasive neuromodulatory techniques. Taken together, these advances could make VCI a potentially preventable cause of both vascular and degenerative dementia in late life. This review provides a timely update on the recent serological, cerebrospinal fluid, histopathological, imaging, and neurophysiological studies on this "cutting-edge" topic, including the limitations, future perspectives and translational implications in the diagnosis and management of VCI patients.
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Affiliation(s)
- Luisa Vinciguerra
- Department of Neurology and Stroke Unit, ASST Cremona, 26100 Cremona, Italy; (L.V.); (V.P.)
| | - Giuseppe Lanza
- Department of Surgery and Medical-Surgical Specialties, University of Catania, 95123 Catania, Italy
- Department of Neurology IC, Oasi Research Institute – IRCCS, 94018 Troina, Italy
| | - Valentina Puglisi
- Department of Neurology and Stroke Unit, ASST Cremona, 26100 Cremona, Italy; (L.V.); (V.P.)
| | - Francesco Fisicaro
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy; (F.F.); (M.P.)
| | - Manuela Pennisi
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy; (F.F.); (M.P.)
| | - Rita Bella
- Department of Medical and Surgical Sciences and Advanced Technologies, University of Catania, 95123 Catania, Italy;
| | - Mariagiovanna Cantone
- Department of Neurology, Sant’Elia Hospital, ASP Caltanissetta, 93100 Caltanissetta, Italy;
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14
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Update on the Neurobiology of Vascular Cognitive Impairment: From Lab to Clinic. Int J Mol Sci 2020. [PMID: 32340195 DOI: 10.3390/ijms21082977.] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
In the last years, there has been a significant growth in the literature exploring the pathophysiology of vascular cognitive impairment (VCI). As an "umbrella term" encompassing any degree of vascular-related cognitive decline, VCI is deemed to be the most common cognitive disorder in the elderly, with a significant impact on social and healthcare expenses. Interestingly, some of the molecular, biochemical, and electrophysiological abnormalities detected in VCI seem to correlate with disease process and progression, eventually promoting an adaptive plasticity in some patients and a maladaptive, dysfunctional response in others. However, the exact relationships between vascular lesion, cognition, and neuroplasticity are not completely understood. Recent findings point out also the possibility to identify a panel of markers able to predict cognitive deterioration in the so-called "brain at risk" for vascular or mixed dementia. This will be of pivotal importance when designing trials of disease-modifying drugs or non-pharmacological approaches, including non-invasive neuromodulatory techniques. Taken together, these advances could make VCI a potentially preventable cause of both vascular and degenerative dementia in late life. This review provides a timely update on the recent serological, cerebrospinal fluid, histopathological, imaging, and neurophysiological studies on this "cutting-edge" topic, including the limitations, future perspectives and translational implications in the diagnosis and management of VCI patients.
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15
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Parker DB, Razlighi QR. Task-evoked Negative BOLD Response and Functional Connectivity in the Default Mode Network are Representative of Two Overlapping but Separate Neurophysiological Processes. Sci Rep 2019; 9:14473. [PMID: 31597927 PMCID: PMC6785640 DOI: 10.1038/s41598-019-50483-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 08/30/2019] [Indexed: 01/21/2023] Open
Abstract
The topography of the default mode network (DMN) can be obtained with one of two different functional magnetic resonance imaging (fMRI) methods: either from the spontaneous but organized synchrony of the low-frequency fluctuations in resting-state fMRI (rs-fMRI), known as "functional connectivity", or from the consistent and robust deactivations in task-based fMRI (tb-fMRI), here referred to as the "negative BOLD response" (NBR). These two methods are fundamentally different, but their results are often used interchangeably to describe the brain's resting-state, baseline, or intrinsic activity. While the DMN was initially defined by consistent task-based decreases in blood flow in a set of specific brain regions using PET imaging, recently nearly all studies on the DMN employ functional connectivity in rs-fMRI. In this study, we first show the high level of spatial overlap between NBR and functional connectivity of the DMN extracted from the same tb-fMRI scan; then, we demonstrate that the NBR in putative DMN regions can be significantly altered without causing any change in their overlapping functional connectivity. Furthermore, we present evidence that in the DMN, the NBR is more closely related to task performance than the functional connectivity. We conclude that the NBR and functional connectivity of the DMN reflect two separate but overlapping neurophysiological processes, and thus should be differentiated in studies investigating brain-behavior relationships in both healthy and diseased populations. Our findings further raise the possibility that the macro-scale networks of the human brain might internally exhibit a hierarchical functional architecture.
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Affiliation(s)
- David B Parker
- Department of Biomedical Engineering, Columbia University, New York, NY, 10027, USA
| | - Qolamreza R Razlighi
- Department of Biomedical Engineering, Columbia University, New York, NY, 10027, USA.
- Department of Neurology, College of Physicians and Surgeons, Columbia University Medial Center, New York, NY, 10032, USA.
- Taub Institute for research on Alzheimer's disease and the aging brain, Columbia University Medical Center, New York, NY, 10032, USA.
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16
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Fanoudi S, Alavi MS, Hosseini M, Sadeghnia HR. Nigella sativa and thymoquinone attenuate oxidative stress and cognitive impairment following cerebral hypoperfusion in rats. Metab Brain Dis 2019; 34:1001-1010. [PMID: 31016464 DOI: 10.1007/s11011-019-00394-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Accepted: 02/04/2019] [Indexed: 11/28/2022]
Abstract
Nigella sativa, a plant widely used in traditional medicine, possesses anti-inflammatory, antioxidant and neuroprotective properties. In the present study, we investigated the effect of hydroalcoholic extract of N. sativa seeds (NSE) and its active constituent, thymoquinone (TQ), on learning and memory deficits, hippocampal acetylcholine esterase (AChE) activity, and markers of redox status, mainly lipid peroxidation and superoxide dismutase (SOD) activity following cerebral hypoperfusion in rats. Cerebral hypoperfusion was induced by permanent occlusion of bilateral common carotid arteries (2VO). Male Wistar rats were administered either a vehicle (sham group: 10 ml/kg/day, ip), NSE (100, 200, and 400 mg/kg/day, ip), TQ (10, 20, and 40 mg/kg/day, ip), or donepezil (5 mg/kg/day, ip) for 10 days (three days before and seven days after ligation). Spatial learning and memory deficits were investigated using the Morris water maze (MWM) task. 2VO produced significant learning and memory deficits as evidenced by increased latency time to reach the hidden platform, increased swimming time, and decreased time spent in the target quadrant in the probe trial in the MWM task. There was also a significant increase in the lipid peroxidation level and AChE activity, and a significant decrease in SOD activity in the hippocampal portion of hypoperfused rats, as compared with the sham group. Treatment with NSE (400 mg/kg/day; p < 0.001) and TQ (40 mg/kg/day; p < 0.001), as well as donepezil significantly prevented learning and memory impairments and alleviated changes in the hippocampal lipid peroxide level and SOD and AChE activities in this model. In conclusion, our data suggest that N. sativa and thymoquinone have a beneficial role in cerebrovascular insufficiency states and dementia.
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Affiliation(s)
- Sahar Fanoudi
- Pharmacological Research Center of Medicinal Plants, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohaddeseh S Alavi
- Division of Neurocognitive Sciences, Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mahmoud Hosseini
- Division of Neurocognitive Sciences, Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hamid R Sadeghnia
- Pharmacological Research Center of Medicinal Plants, Mashhad University of Medical Sciences, Mashhad, Iran.
- Division of Neurocognitive Sciences, Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
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17
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On the existence of mechanoreceptors within the neurovascular unit of the mammalian brain. Brain Struct Funct 2019; 224:2247-2267. [PMID: 31190162 DOI: 10.1007/s00429-019-01863-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 03/16/2019] [Indexed: 10/26/2022]
Abstract
We describe a set of perivascular interneurons (PINs) with series of fibro-vesicular complexes (FVCs) throughout the gray matter of the adult rabbit and rat brains. PIN-FVCs are ubiquitous throughout the brain vasculature as detected in Golgi-impregnated specimens. Most PINs are small, aspiny cells with short or long (> 1 mm) axons that split and travel along arterial blood vessels. Upon ramification, axons form FVCs around the arising vascular branches; then, paired axons run parallel to the vessel wall until another ramification ensues, and a new FVC is formed. Cytologically, FVCs consist of clusters of perivascular bulbs (PVBs) encircling the precapillary and capillary wall surrounded by end-feet and the extracellular matrix of endothelial cells and pericytes. A PVB contains mitochondria, multivesicular bodies, and granules with a membranous core, similar to Meissner corpuscles and other mechanoreceptors. Some PVBs form asymmetrical, axo-spinous synapses with presumptive adjacent neurons. PINs appear to correspond to the type 1 nNOS-positive neurons whose FVCs co-label with markers of sensory fiber-terminals surrounded by astrocytic end-feet. The PIN is conserved in adult cats and rhesus monkey specimens. The location, ubiquity throughout the vasculature of the mammalian brain, and cytological organization of the PIN-FVCs suggests that it is a sensory receptor intrinsic to the mammalian neurovascular unit that corresponds to an afferent limb of the sensorimotor feed-back mechanism controlling local blood flow.
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18
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Govindpani K, McNamara LG, Smith NR, Vinnakota C, Waldvogel HJ, Faull RL, Kwakowsky A. Vascular Dysfunction in Alzheimer's Disease: A Prelude to the Pathological Process or a Consequence of It? J Clin Med 2019; 8:E651. [PMID: 31083442 PMCID: PMC6571853 DOI: 10.3390/jcm8050651] [Citation(s) in RCA: 111] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 04/29/2019] [Accepted: 05/06/2019] [Indexed: 12/19/2022] Open
Abstract
Alzheimer's disease (AD) is the most prevalent form of dementia. Despite decades of research following several theoretical and clinical lines, all existing treatments for the disorder are purely symptomatic. AD research has traditionally been focused on neuronal and glial dysfunction. Although there is a wealth of evidence pointing to a significant vascular component in the disease, this angle has been relatively poorly explored. In this review, we consider the various aspects of vascular dysfunction in AD, which has a significant impact on brain metabolism and homeostasis and the clearance of β-amyloid and other toxic metabolites. This may potentially precede the onset of the hallmark pathophysiological and cognitive symptoms of the disease. Pathological changes in vessel haemodynamics, angiogenesis, vascular cell function, vascular coverage, blood-brain barrier permeability and immune cell migration may be related to amyloid toxicity, oxidative stress and apolipoprotein E (APOE) genotype. These vascular deficits may in turn contribute to parenchymal amyloid deposition, neurotoxicity, glial activation and metabolic dysfunction in multiple cell types. A vicious feedback cycle ensues, with progressively worsening neuronal and vascular pathology through the course of the disease. Thus, a better appreciation for the importance of vascular dysfunction in AD may open new avenues for research and therapy.
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Affiliation(s)
- Karan Govindpani
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Laura G McNamara
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Nicholas R Smith
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Chitra Vinnakota
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Henry J Waldvogel
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Richard Lm Faull
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Andrea Kwakowsky
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
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19
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Zuccolo E, Laforenza U, Negri S, Botta L, Berra-Romani R, Faris P, Scarpellino G, Forcaia G, Pellavio G, Sancini G, Moccia F. Muscarinic M5 receptors trigger acetylcholine-induced Ca 2+ signals and nitric oxide release in human brain microvascular endothelial cells. J Cell Physiol 2018; 234:4540-4562. [PMID: 30191989 DOI: 10.1002/jcp.27234] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 07/24/2018] [Indexed: 12/13/2022]
Abstract
Basal forebrain neurons control cerebral blood flow (CBF) by releasing acetylcholine (Ach), which binds to endothelial muscarinic receptors to induce nitric (NO) release and vasodilation in intraparenchymal arterioles. Nevertheless, the mechanism whereby Ach stimulates human brain microvascular endothelial cells to produce NO is still unknown. Herein, we sought to assess whether Ach stimulates NO production in a Ca2+ -dependent manner in hCMEC/D3 cells, a widespread model of human brain microvascular endothelial cells. Ach induced a dose-dependent increase in intracellular Ca2+ concentration ([Ca2+ ]i ) that was prevented by the genetic blockade of M5 muscarinic receptors (M5-mAchRs), which was the only mAchR isoform coupled to phospholipase Cβ (PLCβ) present in hCMEC/D3 cells. A comprehensive real-time polymerase chain reaction analysis revealed the expression of the transcripts encoding for type 3 inositol-1,4,5-trisphosphate receptors (InsP3 R3), two-pore channels 1 and 2 (TPC1-2), Stim2, Orai1-3. Pharmacological manipulation showed that the Ca2+ response to Ach was mediated by InsP3 R3, TPC1-2, and store-operated Ca2+ entry (SOCE). Ach-induced NO release, in turn, was inhibited in cells deficient of M5-mAchRs. Likewise, Ach failed to increase NO levels in the presence of l-NAME, a selective NOS inhibitor, or BAPTA, a membrane-permeant intracellular Ca2+ buffer. Moreover, the pharmacological blockade of the Ca2+ response to Ach also inhibited the accompanying NO production. These data demonstrate for the first time that synaptically released Ach may trigger NO release in human brain microvascular endothelial cells by stimulating a Ca2+ signal via M5-mAchRs.
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Affiliation(s)
- Estella Zuccolo
- Department of Biology and Biotechnology, "Lazzaro Spallanzani," Laboratory of General Physiology, University of Pavia, Pavia, Italy
| | - Umberto Laforenza
- Department of Molecular Medicine, Human Physiology Unit, University of Pavia, Pavia, Italy
| | - Sharon Negri
- Department of Biology and Biotechnology, "Lazzaro Spallanzani," Laboratory of General Physiology, University of Pavia, Pavia, Italy
| | - Laura Botta
- Department of Biology and Biotechnology, "Lazzaro Spallanzani," Laboratory of General Physiology, University of Pavia, Pavia, Italy
| | - Roberto Berra-Romani
- Department of Biomedicine, School of Medicine, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Pawan Faris
- Department of Biology and Biotechnology, "Lazzaro Spallanzani," Laboratory of General Physiology, University of Pavia, Pavia, Italy.,Department of Biology, College of Science, Salahaddin University, Erbil, Iraq
| | - Giorgia Scarpellino
- Department of Biology and Biotechnology, "Lazzaro Spallanzani," Laboratory of General Physiology, University of Pavia, Pavia, Italy
| | - Greta Forcaia
- Department of Experimental Medicine, University of Milano-Bicocca, Monza, Italy
| | - Giorgia Pellavio
- Department of Molecular Medicine, Human Physiology Unit, University of Pavia, Pavia, Italy
| | - Giulio Sancini
- Department of Experimental Medicine, University of Milano-Bicocca, Monza, Italy
| | - Francesco Moccia
- Department of Biology and Biotechnology, "Lazzaro Spallanzani," Laboratory of General Physiology, University of Pavia, Pavia, Italy
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20
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Schulz JM, Al-Khazraji BK, Shoemaker JK. Sodium nitroglycerin induces middle cerebral artery vasodilatation in young, healthy adults. Exp Physiol 2018; 103:1047-1055. [PMID: 29766604 PMCID: PMC6099468 DOI: 10.1113/ep087022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 05/08/2018] [Indexed: 01/03/2023]
Abstract
NEW FINDINGS What is the central question of this study? Nitric oxide causes dilatation in peripheral vessels; however, whether nitric oxide affects basal cerebral artery dilatation has not been explored. What is the main finding and its importance? This study demonstrated that vasodilatation occurs in the right middle cerebral artery in response to exogenous nitric oxide. However, blood velocity decreased and, therefore, overall cerebral blood flow remained unchanged. This study provides new insight into the role of nitric oxide in cerebral blood flow control. ABSTRACT Recent evidence indicates that basal cerebral conduit vessels dilate with hypercapnia, with a nitric oxide (NO) mechanism explaining one way in which parenchymal cerebral arterioles dilate. However, whether NO affects basal cerebral artery dilatation remains unknown. This study quantified the effect of an exogenous NO donor [sodium nitroglycerin (NTG); 0.4 mg sublingual spray] on the right middle cerebral artery (rMCA) cross-sectional area (CSA), blood velocity and overall blood flow. Measures of vessel CSA (7 T magnetic resonance imaging) and MCA blood velocity (transcranial Doppler ultrasound) were made at baseline (BL) and after exogenous NTG or placebo (PLO) administration in young, healthy individuals (n = 10, two males, age range 20-23 years). The CSA increased in the rMCA [BL, 5.2 ± 1.2 mm2 ; PLO, 5.4 ± 1.5 mm2 ; NTG, 6.6 ± 1.5 mm2 , P < 0.05; mean ± SD]. Concurrently, rMCA blood velocity decreased from BL during NTG compared with PLO (BL, 67 ± 10 cm s-1 ; PLO, 62 ± 10 cm s-1 ; NTG, 59 ± 9.3 cm s-1 , P < 0.05; mean ± SD]. However, total MCA blood flow did not change with NTG or PLO [BL, 221 ± 37.4 ml min-1 ; PLO, 218 ± 35.0 ml min-1 ; NTG, 213 ± 46.4 ml min-1 ). Therefore, exogenous NO mediates a dilatory response in the rMCA, but not in its downstream vascular bed.
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Affiliation(s)
- Jenna M Schulz
- School of Physical Therapy, Department of Health Sciences, Western University, London, ON, Canada
| | - Baraa K Al-Khazraji
- School of Kinesiology, Department of Health Sciences, Western University, London, ON, Canada
| | - J Kevin Shoemaker
- Department of Physiology and Pharmacology, Western University, London, ON, Canada.,School of Kinesiology, Department of Health Sciences, Western University, London, ON, Canada
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21
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Chen JJ. Functional MRI of brain physiology in aging and neurodegenerative diseases. Neuroimage 2018; 187:209-225. [PMID: 29793062 DOI: 10.1016/j.neuroimage.2018.05.050] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 05/16/2018] [Accepted: 05/20/2018] [Indexed: 12/14/2022] Open
Abstract
Brain aging and associated neurodegeneration constitute a major societal challenge as well as one for the neuroimaging community. A full understanding of the physiological mechanisms underlying neurodegeneration still eludes medical researchers, fuelling the development of in vivo neuroimaging markers. Hence it is increasingly recognized that our understanding of neurodegenerative processes likely will depend upon the available information provided by imaging techniques. At the same time, the imaging techniques are often developed in response to the desire to observe certain physiological processes. In this context, functional MRI (fMRI), which has for decades provided information on neuronal activity, has evolved into a large family of techniques well suited for in vivo observations of brain physiology. Given the rapid technical advances in fMRI in recent years, this review aims to summarize the physiological basis of fMRI observations in healthy aging as well as in age-related neurodegeneration. This review focuses on in-vivo human brain imaging studies in this review and on disease features that can be imaged using fMRI methods. In addition to providing detailed literature summaries, this review also discusses future directions in the study of brain physiology using fMRI in the clinical setting.
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Affiliation(s)
- J Jean Chen
- Rotman Research Institute at Baycrest Centre, Canada; Department of Medical Biophysics, University of Toronto, Canada.
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22
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Harder DR, Rarick KR, Gebremedhin D, Cohen SS. Regulation of Cerebral Blood Flow: Response to Cytochrome P450 Lipid Metabolites. Compr Physiol 2018; 8:801-821. [PMID: 29687906 DOI: 10.1002/cphy.c170025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
There have been numerous reviews related to the cerebral circulation. Most of these reviews are similar in many ways. In the present review, we thought it important to provide an overview of function with specific attention to details of cerebral arterial control related to brain homeostasis, maintenance of neuronal energy demands, and a unique perspective related to the role of astrocytes. A coming review in this series will discuss cerebral vascular development and unique properties of the neonatal circulation and developing brain, thus, many aspects of development are missing here. Similarly, a review of the response of the brain and cerebral circulation to heat stress has recently appeared in this series (8). By trying to make this review unique, some obvious topics were not discussed in lieu of others, which are from recent and provocative research such as endothelium-derived hyperpolarizing factor, circadian regulation of proteins effecting cerebral blood flow, and unique properties of the neurovascular unit. © 2018 American Physiological Society. Compr Physiol 8:801-821, 2018.
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Affiliation(s)
- David R Harder
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.,Clement J. Zablocki VA Medical Center, Milwaukee, Wisconsin, USA
| | - Kevin R Rarick
- Department of Pediatrics, Division of Critical Care, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Debebe Gebremedhin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Susan S Cohen
- Department of Pediatrics, Division of Neonatology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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23
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Guerra G, Lucariello A, Perna A, Botta L, De Luca A, Moccia F. The Role of Endothelial Ca 2+ Signaling in Neurovascular Coupling: A View from the Lumen. Int J Mol Sci 2018; 19:E938. [PMID: 29561829 PMCID: PMC5979341 DOI: 10.3390/ijms19040938] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 03/16/2018] [Accepted: 03/17/2018] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Neurovascular coupling (NVC) is the mechanism whereby an increase in neuronal activity (NA) leads to local elevation in cerebral blood flow (CBF) to match the metabolic requirements of firing neurons. Following synaptic activity, an increase in neuronal and/or astrocyte Ca2+ concentration leads to the synthesis of multiple vasoactive messengers. Curiously, the role of endothelial Ca2+ signaling in NVC has been rather neglected, although endothelial cells are known to control the vascular tone in a Ca2+-dependent manner throughout peripheral vasculature. METHODS We analyzed the literature in search of the most recent updates on the potential role of endothelial Ca2+ signaling in NVC. RESULTS We found that several neurotransmitters (i.e., glutamate and acetylcholine) and neuromodulators (e.g., ATP) can induce dilation of cerebral vessels by inducing an increase in endothelial Ca2+ concentration. This, in turn, results in nitric oxide or prostaglandin E2 release or activate intermediate and small-conductance Ca2+-activated K⁺ channels, which are responsible for endothelial-dependent hyperpolarization (EDH). In addition, brain endothelial cells express multiple transient receptor potential (TRP) channels (i.e., TRPC3, TRPV3, TRPV4, TRPA1), which induce vasodilation by activating EDH. CONCLUSIONS It is possible to conclude that endothelial Ca2+ signaling is an emerging pathway in the control of NVC.
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Affiliation(s)
- Germano Guerra
- Department of Medicine and Health Sciences "Vincenzo Tiberio", University of Molise, via F. De Santis, 86100 Campobasso, Italy.
| | - Angela Lucariello
- Department of Mental Health and Preventive Medicine, Section of Human Anatomy, University of Campania "L. Vanvitelli", 81100 Naples, Italy.
| | - Angelica Perna
- Department of Medicine and Health Sciences "Vincenzo Tiberio", University of Molise, via F. De Santis, 86100 Campobasso, Italy.
| | - Laura Botta
- Laboratory of General Physiology, Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, via Forlanini 6, 27100 Pavia, Italy.
| | - Antonio De Luca
- Department of Mental Health and Preventive Medicine, Section of Human Anatomy, University of Campania "L. Vanvitelli", 81100 Naples, Italy.
| | - Francesco Moccia
- Laboratory of General Physiology, Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, via Forlanini 6, 27100 Pavia, Italy.
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Chi L, Du K, Liu D, Bo Y, Li W. Electroacupuncture brain protection during ischemic stroke: A role for the parasympathetic nervous system. J Cereb Blood Flow Metab 2018; 38:479-491. [PMID: 28281385 PMCID: PMC5851138 DOI: 10.1177/0271678x17697988] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 01/09/2017] [Accepted: 02/07/2017] [Indexed: 12/19/2022]
Abstract
The demand for using parasympathetic activation for stroke therapy is unmet. In the current study, we investigated whether the neuroprotection provided by electroacupuncture (EA) in an experimental stroke model was associated with activation of the parasympathetic nervous system (PNS). The results showed that parasympathetic dysfunction (PD), performed as unilateral vagotomy combined with peripheral atropine, attenuated both the functional benefits of EA and its effects in improving cerebral perfusion, reducing infarct volume, and hindering apoptosis, neuronal and peripheral inflammation, and oxidative stress. Most importantly, EA rats showed a dramatically less reduction in the mRNA level of choline acetyltransferase, five subtypes of muscarinic receptors and α7nAChR, suggesting the inhibition of the impairment of the central cholinergic system; EA also activated dorsal motor nucleus of the vagus, the largest source of parasympathetic pre-ganglionic neurons in the lower brainstem (detected by c-fos immunohistochemistry), and PD suppressed these changes. These findings indicated EA may serve as an alternative modality of PNS activation for stroke therapy.
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Affiliation(s)
- Laiting Chi
- Department of Anesthesiology, Second Affiliated Hospital of Harbin Medical University, Harbin, China
- Heilongjiang Province Key Lab of Research on Anesthesiology and Critical Care Medicine, Harbin, China
| | - Kairong Du
- Department of Anesthesiology, Second Affiliated Hospital of Harbin Medical University, Harbin, China
- Heilongjiang Province Key Lab of Research on Anesthesiology and Critical Care Medicine, Harbin, China
| | - Dongdong Liu
- Department of Anesthesiology, Second Affiliated Hospital of Harbin Medical University, Harbin, China
- Heilongjiang Province Key Lab of Research on Anesthesiology and Critical Care Medicine, Harbin, China
| | - Yulong Bo
- Department of Anesthesiology, Second Affiliated Hospital of Harbin Medical University, Harbin, China
- Heilongjiang Province Key Lab of Research on Anesthesiology and Critical Care Medicine, Harbin, China
| | - Wenzhi Li
- Department of Anesthesiology, Second Affiliated Hospital of Harbin Medical University, Harbin, China
- Heilongjiang Province Key Lab of Research on Anesthesiology and Critical Care Medicine, Harbin, China
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Reduced substantia innominata volume mediates contributions of microvascular and macrovascular disease to cognitive deficits in Alzheimer's disease. Neurobiol Aging 2018; 66:23-31. [PMID: 29505952 DOI: 10.1016/j.neurobiolaging.2018.01.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 01/29/2018] [Accepted: 01/31/2018] [Indexed: 01/06/2023]
Abstract
The relationships between cholinergic system damage and cerebrovascular disease are not entirely understood. Here, we investigate associations between atrophy of the substantia innominata (SI; the origin of cortical cholinergic projections) and measures of large and small vessel disease; specifically, elongation of the juxtaposed internal carotid artery termination and Cholinergic Pathways Hyperintensity scores (CHIPS). The study (n = 105) consisted of patients with Alzheimer's disease (AD) and/or subcortical ischemic vasculopathy, and elderly controls. AD and subcortical ischemic vasculopathy groups showed greater impingement of the carotid termination on the SI and smaller SI volumes. Both carotid termination elongation and CHIPS were associated independently with smaller SI volumes in those with and without AD. Atrophy of the SI mediated effects of carotid termination elongation on language and memory functions and the effect of CHIPS on attention/working memory. In conclusion, SI atrophy was related to cerebrovascular disease of the large and small vessels and to cognitive deficits in people with and without AD.
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Kheirbakhsh R, Haddadi M, Muhammadnejad A, Abdollahi A, Shahi F, Amanpour-Gharaei B, Abrahim-Habibi A, Barati T, Amanpour S. Long-term behavioral, histological, biochemical and hematological evaluations of amyloid beta-induced Alzheimer’s disease in rat. Acta Neurobiol Exp (Wars) 2018. [DOI: 10.21307/ane-2018-004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Hall CN, Howarth C, Kurth-Nelson Z, Mishra A. Interpreting BOLD: towards a dialogue between cognitive and cellular neuroscience. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0348. [PMID: 27574302 DOI: 10.1098/rstb.2015.0348] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/11/2016] [Indexed: 12/11/2022] Open
Abstract
Cognitive neuroscience depends on the use of blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) to probe brain function. Although commonly used as a surrogate measure of neuronal activity, BOLD signals actually reflect changes in brain blood oxygenation. Understanding the mechanisms linking neuronal activity to vascular perfusion is, therefore, critical in interpreting BOLD. Advances in cellular neuroscience demonstrating differences in this neurovascular relationship in different brain regions, conditions or pathologies are often not accounted for when interpreting BOLD. Meanwhile, within cognitive neuroscience, the increasing use of high magnetic field strengths and the development of model-based tasks and analyses have broadened the capability of BOLD signals to inform us about the underlying neuronal activity, but these methods are less well understood by cellular neuroscientists. In 2016, a Royal Society Theo Murphy Meeting brought scientists from the two communities together to discuss these issues. Here, we consolidate the main conclusions arising from that meeting. We discuss areas of consensus about what BOLD fMRI can tell us about underlying neuronal activity, and how advanced modelling techniques have improved our ability to use and interpret BOLD. We also highlight areas of controversy in understanding BOLD and suggest research directions required to resolve these issues.This article is part of the themed issue 'Interpreting BOLD: a dialogue between cognitive and cellular neuroscience'.
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Affiliation(s)
| | - Clare Howarth
- Department of Psychology, University of Sheffield, Sheffield, UK
| | - Zebulun Kurth-Nelson
- Max Planck UCL Centre for Computational Psychiatry and Ageing Research, University College London, London, UK
| | - Anusha Mishra
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
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28
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Sommer JB, Bach A, Malá H, Strømgaard K, Mogensen J, Pickering DS. Effects of the dimeric PSD-95 inhibitor UCCB01-144 on functional recovery after fimbria-fornix transection in rats. Pharmacol Biochem Behav 2017; 161:62-67. [PMID: 28943199 DOI: 10.1016/j.pbb.2017.09.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Revised: 08/22/2017] [Accepted: 09/18/2017] [Indexed: 01/05/2023]
Abstract
Pharmacological inhibition of PSD-95 is a promising therapeutic strategy in the treatment of stroke, and positive effects of monomeric and dimeric PSD-95 inhibitors have been reported in numerous studies. However, whether therapeutic effects will generalize to other types of acute brain injury such as traumatic brain injury (TBI), which has pathophysiological mechanisms in common with stroke, is currently uncertain. We have previously found a lack of neuroprotective effects of dimeric PSD-95 inhibitors in the controlled cortical impact model of TBI in rats. However, as no single animal model is currently able to mimic the complex and heterogeneous pathophysiology of TBI, it is necessary to assess treatment effects across a range of models. In this preliminary study we investigated the neuroprotective abilities of the dimeric PSD-95 inhibitor UCCB01-144 after fimbria-fornix (FF) transection in rats. UCCB01-144 or saline was injected into the lateral tail vein of rats immediately after sham surgery or FF-transection, and effects on spatial delayed alternation in a T-maze were assessed over a 28-day period. Task acquisition was significantly impaired in FF-transected animals, but there were no significant effects of UCCB01-144 on spatial delayed alternation after FF-transection or sham surgery, although decelerated learning curves were seen after treatment with UCCB01-144 in FF-transected animals. The results of the present study are consistent with previous research showing a lack of neuroprotective effects of PSD-95 inhibition in experimental models of TBI.
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Affiliation(s)
- Jens Bak Sommer
- Department of Drug Design and Pharmacology, University of Copenhagen, Denmark; The Unit for Cognitive Neuroscience (UCN), Department of Psychology, University of Copenhagen, Denmark.
| | - Anders Bach
- Department of Drug Design and Pharmacology, University of Copenhagen, Denmark.
| | - Hana Malá
- The Unit for Cognitive Neuroscience (UCN), Department of Psychology, University of Copenhagen, Denmark.
| | - Kristian Strømgaard
- Department of Drug Design and Pharmacology, University of Copenhagen, Denmark.
| | - Jesper Mogensen
- The Unit for Cognitive Neuroscience (UCN), Department of Psychology, University of Copenhagen, Denmark.
| | - Darryl S Pickering
- Department of Drug Design and Pharmacology, University of Copenhagen, Denmark.
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Sokolov AY, Murzina AA, Osipchuk AV, Lyubashina OA, Amelin AV. Cholinergic mechanisms of headaches. NEUROCHEM J+ 2017. [DOI: 10.1134/s1819712417020131] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Sweeney MD, Ayyadurai S, Zlokovic BV. Pericytes of the neurovascular unit: key functions and signaling pathways. Nat Neurosci 2017; 19:771-83. [PMID: 27227366 DOI: 10.1038/nn.4288] [Citation(s) in RCA: 689] [Impact Index Per Article: 98.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 02/29/2016] [Indexed: 12/12/2022]
Abstract
Pericytes are vascular mural cells embedded in the basement membrane of blood microvessels. They extend their processes along capillaries, pre-capillary arterioles and post-capillary venules. CNS pericytes are uniquely positioned in the neurovascular unit between endothelial cells, astrocytes and neurons. They integrate, coordinate and process signals from their neighboring cells to generate diverse functional responses that are critical for CNS functions in health and disease, including regulation of the blood-brain barrier permeability, angiogenesis, clearance of toxic metabolites, capillary hemodynamic responses, neuroinflammation and stem cell activity. Here we examine the key signaling pathways between pericytes and their neighboring endothelial cells, astrocytes and neurons that control neurovascular functions. We also review the role of pericytes in CNS disorders including rare monogenic diseases and complex neurological disorders such as Alzheimer's disease and brain tumors. Finally, we discuss directions for future studies.
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Affiliation(s)
- Melanie D Sweeney
- Department of Physiology and Biophysics, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA.,Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
| | - Shiva Ayyadurai
- Systems Biology Group, CytoSolve Research Division, Cambridge, Massachusetts, USA
| | - Berislav V Zlokovic
- Department of Physiology and Biophysics, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA.,Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
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31
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Zuccolo E, Lim D, Kheder DA, Perna A, Catarsi P, Botta L, Rosti V, Riboni L, Sancini G, Tanzi F, D'Angelo E, Guerra G, Moccia F. Acetylcholine induces intracellular Ca 2+ oscillations and nitric oxide release in mouse brain endothelial cells. Cell Calcium 2017; 66:33-47. [PMID: 28807148 DOI: 10.1016/j.ceca.2017.06.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 06/05/2017] [Accepted: 06/10/2017] [Indexed: 01/29/2023]
Abstract
Basal forebrain neurons increase cortical blood flow by releasing acetylcholine (Ach), which stimulates endothelial cells (ECs) to produce the vasodilating gasotransmitter, nitric oxide (NO). Surprisingly, the mechanism whereby Ach induces NO synthesis in brain microvascular ECs is unknown. An increase in intracellular Ca2+ concentration recruits a multitude of endothelial Ca2+-dependent pathways, such as Ca2+/calmodulin endothelial NO synthase (eNOS). The present investigation sought to investigate the role of intracellular Ca2+ signaling in Ach-induced NO production in bEND5 cells, an established model of mouse brain microvascular ECs, by conventional imaging of cells loaded with the Ca2+-sensitive dye, Fura-2/AM, and the NO-sensitive fluorophore, DAF-DM diacetate. Ach induced dose-dependent Ca2+ oscillations in bEND5 cells, 300 μM being the most effective dose to generate a prolonged Ca2+ burst. Pharmacological manipulation revealed that Ach-evoked Ca2+ oscillations required metabotropic muscarinic receptor (mAchR) activation and were patterned by a complex interplay between repetitive ER Ca2+ release via inositol-1,4,5-trisphosphate receptors (InsP3Rs) and store-operated Ca2+ entry (SOCE). A comprehensive real time-polymerase chain reaction analysis demonstrated the expression of the transcripts encoding for M3-mAChRs, InsP3R1 and InsP3R3, Stim1-2 and Orai2. Next, we found that Ach-induced NO production was hindered by L-NAME, a selective NOS inhibitor, and BAPTA, a membrane permeable intracellular Ca2+ buffer. Moreover, Ach-elicited NO synthesis was blocked by the pharmacological abrogation of the accompanying Ca2+ spikes. Overall, these data shed novel light on the molecular mechanisms whereby neuronally-released Ach controls neurovascular coupling in blood microvessels.
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Affiliation(s)
- Estella Zuccolo
- Laboratory of General Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy
| | - Dmitry Lim
- Department of Pharmaceutical Sciences, University of Eastern Piedment "Amedeo Avogadro", Novara, Italy
| | - Dlzar Ali Kheder
- Laboratory of General Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy; Department of Biology, University of Zakho, Kurdistan-Region of Iraq, Iraq
| | - Angelica Perna
- Department of Medicine and Health Sciences "Vincenzo Tiberio", University of Molise, Via F. De Santis, 86100 Campobasso, Italy
| | - Paolo Catarsi
- Center for the Study of Myelofibrosis, Research Laboratory of Biotechnology, Foundation IRCCS Policlinico San Matteo, Pavia, Italy
| | - Laura Botta
- Laboratory of General Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy
| | - Vittorio Rosti
- Center for the Study of Myelofibrosis, Research Laboratory of Biotechnology, Foundation IRCCS Policlinico San Matteo, Pavia, Italy
| | - Laura Riboni
- Department of Medical Biotechnology and Translational Medicine, LITA-Segrate, University of Milan, Segrate, 20090 Milan, Italy
| | - Giulio Sancini
- Department of Experimental Medicine, University of Milano-Bicocca, 20900 Monza, Italy
| | - Franco Tanzi
- Laboratory of General Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy
| | - Egidio D'Angelo
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy; Brain Connectivity Center, C. Mondino National Neurological Institute, 27100 Pavia, Italy
| | - Germano Guerra
- Department of Medicine and Health Sciences "Vincenzo Tiberio", University of Molise, Via F. De Santis, 86100 Campobasso, Italy.
| | - Francesco Moccia
- Laboratory of General Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy.
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Serrador JM, Freeman R. Enhanced Cholinergic Activity Improves Cerebral Blood Flow during Orthostatic Stress. Front Neurol 2017; 8:103. [PMID: 28373858 PMCID: PMC5357636 DOI: 10.3389/fneur.2017.00103] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 03/02/2017] [Indexed: 02/05/2023] Open
Abstract
Cerebral blood flow (CBF) and consequently orthostatic tolerance when upright depends on dilation of the cerebral vasculature in the face of reduced perfusion pressure associated with the hydrostatic gradient. However, it is still unclear if cholinergic activation plays a role in this dilation. To determine if enhancing central cholinergic activity with the centrally acting acetylcholinesterase inhibitor, physostigmine would increase CBF when upright compared to the peripherally acting acetylcholinesterase inhibitor, neostigmine, or saline. We performed a randomized double-blind dose-ranging study that took place over 3 days in a hospital-based research lab. Eight healthy controls (six women and two men, mean age, 26 years; range 21–33) were given infusions of physostigmine, neostigmine, or saline on three different days. Five-minute tilts were repeated at baseline (no infusion), Dose 1 (0.2 μg/kg/min physostigmine; 0.1 μg/kg/min neostigmine) and Dose 2 (0.6 μg/kg/min physostigmine or 0.3 μg/kg/min neostigmine), and placebo (0.9% NaCl). Cerebral blood velocity, beat-to-beat blood pressure, and end-tidal CO2 were continuously measured during tilts. Physostigmine (0.6 μg/kg/min) resulted in higher cerebral blood velocity during tilt (90.5 ± 1.5%) than the equivalent neostigmine (85.5 ± 2.6%) or saline (84.8 ± 1.7%) trials (P < 0.05). This increase occurred despite a greater postural hypocapnia, suggesting physostigmine had a direct vasodilatory effect on the cerebral vasculature. Cerebral hypoperfusion induced by repeated tilts was eliminated by infusion of physostigmine not neostigmine. In conclusion, this study provides the first evidence that enhancement of central, not peripheral, cholinergic activity attenuates the physiological decrease in CBF seen during upright tilt. These data support the need for further research to determine if enhancing central cholinergic activity may improve symptoms in patients with symptomatic orthostatic intolerance.
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Affiliation(s)
- Jorge M Serrador
- Department of Pharmacology, Physiology and Neuroscience, Rutgers Biomedical Health Sciences, Newark, NJ, USA; Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Cardiovascular Electronics, National University of Ireland Galway, Galway, Ireland
| | - Roy Freeman
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School , Boston, MA , USA
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Mishra A. Binaural blood flow control by astrocytes: listening to synapses and the vasculature. J Physiol 2016; 595:1885-1902. [PMID: 27619153 DOI: 10.1113/jp270979] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 07/15/2016] [Indexed: 12/28/2022] Open
Abstract
Astrocytes are the most common glial cells in the brain with fine processes and endfeet that intimately contact both neuronal synapses and the cerebral vasculature. They play an important role in mediating neurovascular coupling (NVC) via several astrocytic Ca2+ -dependent signalling pathways such as K+ release through BK channels, and the production and release of arachidonic acid metabolites. They are also involved in maintaining the resting tone of the cerebral vessels by releasing ATP and COX-1 derivatives. Evidence also supports a role for astrocytes in maintaining blood pressure-dependent change in cerebrovascular tone, and perhaps also in blood vessel-to-neuron signalling as posited by the 'hemo-neural hypothesis'. Thus, astrocytes are emerging as new stars in preserving the intricate balance between the high energy demand of active neurons and the supply of oxygen and nutrients from the blood by maintaining both resting blood flow and activity-evoked changes therein. Following neuropathology, astrocytes become reactive and many of their key signalling mechanisms are altered, including those involved in NVC. Furthermore, as they can respond to changes in vascular pressure, cardiovascular diseases might exert previously unknown effects on the central nervous system by altering astrocyte function. This review discusses the role of astrocytes in neurovascular signalling in both physiology and pathology, and the impact of these findings on understanding BOLD-fMRI signals.
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Affiliation(s)
- Anusha Mishra
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
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Chen L, Zhang Y, Li D, Zhang N, Liu R, Han B, Wei C, Liu H, Xu X, Hao J. Everolimus (RAD001) ameliorates vascular cognitive impairment by regulating microglial function via the mTORC1 signaling pathway. J Neuroimmunol 2016; 299:164-171. [PMID: 27725116 DOI: 10.1016/j.jneuroim.2016.09.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 09/05/2016] [Accepted: 09/12/2016] [Indexed: 12/14/2022]
Abstract
Vascular dementia (VaD) is a widely prevalent and devastating disease. Despite the tremendous complexity that limits understanding of the pathophysiology of VaD, microglial dysfunction has been attributed, in part, to immune microenviroment disorder and finally leads to cognitive deficits. Considered the mammalian target of rapamycin complex 1 (mTORC1) is a key player in regulation of glial function, our work focused on whether the mTOR inhibitor everolimus (RAD001) could overcome the destructive microglial function, change the phenotype and ameliorate cognitive decline induced by chronic cerebral hypoperfusion. Strikingly, the results suggest that inhibition of the mTORC1 activity by RAD001 ameliorates VaD by restoring microglia's M1/M2 balance. Therefore, RAD001 may have promise as a therapy for VaD disease.
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Affiliation(s)
- Li Chen
- Department of Neurology and Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin 300052, China; Department of Neurology, Tianjin Huanhu Hospital, Tianjin 300060, China
| | - Yanjun Zhang
- Department of Neurology and Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Daojing Li
- Department of Neurology and Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Nong Zhang
- Department of Neurology and Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Ruiqiong Liu
- Department of Neurology and Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin 300052, China; Tianjin Key Laboratory of Medical Epigenetics, Department of Biochemistry and Molecular Biology, Tianjin Medical University, Tianjin 300070, China
| | - Bin Han
- Department of Neurology and Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Changjuan Wei
- Department of Neurology and Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Haijie Liu
- Department of Neurology and Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Xiaolin Xu
- Department of Neurology, Tianjin Huanhu Hospital, Tianjin 300060, China
| | - Junwei Hao
- Department of Neurology and Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin 300052, China.
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Love S, Miners J. Cerebral Hypoperfusion and the Energy Deficit in Alzheimer's Disease. Brain Pathol 2016; 26:607-17. [PMID: 27327656 PMCID: PMC8028913 DOI: 10.1111/bpa.12401] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 06/21/2016] [Accepted: 05/25/2016] [Indexed: 12/19/2022] Open
Abstract
There is a perfusion deficit in Alzheimer's disease (AD), commencing in the precuneus and spreading to other parts of the cerebral cortex. The deficit anticipates the development of dementia, contributes to brain damage, and is caused by both functional and structural abnormalities of the cerebral vasculature. Most of the abnormalities are probably secondary to the accumulation of Aβ but the consequent hypoperfusion may, in turn, increase Aβ production. In the early stages of disease, abnormalities that cause vasoconstriction predominate. These include cholinergic vascular denervation, inhibition of endothelial nitric oxide synthase, increased production of endothelin-1 production and possibly also of angiotensin II. Patients with AD also have an increased prevalence of structural disease of cerebral microvessels, particularly CAA and capillary damage, and particularly in the later stages of disease these are likely to make an important contribution to the cerebral hypoperfusion. The metabolic abnormalities that cause early vascular dysfunction offer several targets for therapeutic intervention. However, for intervention to be effective it probably needs to be early. Prolonged cerebral hypoperfusion may induce compensatory circulatory changes that are themselves damaging, including hypertension and small vessel disease. This has implications for the use of antihypertensive drugs once there is accumulation of Aβ within the brain.
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Affiliation(s)
- Seth Love
- Dementia Research Group, Institute of Clinical Neurosciences, School of Clinical SciencesUniversity of BristolBristolUnited Kingom
| | - J.Scott Miners
- Dementia Research Group, Institute of Clinical Neurosciences, School of Clinical SciencesUniversity of BristolBristolUnited Kingom
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Filosa JA, Morrison HW, Iddings JA, Du W, Kim KJ. Beyond neurovascular coupling, role of astrocytes in the regulation of vascular tone. Neuroscience 2016; 323:96-109. [PMID: 25843438 PMCID: PMC4592693 DOI: 10.1016/j.neuroscience.2015.03.064] [Citation(s) in RCA: 138] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 03/24/2015] [Accepted: 03/27/2015] [Indexed: 12/22/2022]
Abstract
The brain possesses two intricate mechanisms that fulfill its continuous metabolic needs: cerebral autoregulation, which ensures constant cerebral blood flow over a wide range of arterial pressures and functional hyperemia, which ensures rapid delivery of oxygen and glucose to active neurons. Over the past decade, a number of important studies have identified astrocytes as key intermediaries in neurovascular coupling (NVC), the mechanism by which active neurons signal blood vessels to change their diameter. Activity-dependent increases in astrocytic Ca(2+) activity are thought to contribute to the release of vasoactive substances that facilitate arteriole vasodilation. A number of vasoactive signals have been identified and their role on vessel caliber assessed both in vitro and in vivo. In this review, we discuss mechanisms implicating astrocytes in NVC-mediated vascular responses, limitations encountered as a result of the challenges in maintaining all the constituents of the neurovascular unit intact and deliberate current controversial findings disputing a main role for astrocytes in NVC. Finally, we briefly discuss the potential role of pericytes and microglia in NVC-mediated processes.
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Affiliation(s)
- J A Filosa
- Georgia Regents University, 1120 15th Street, Augusta, GA 30912, United States.
| | - H W Morrison
- University of Arizona, 1305 N. Martin Avenue, P.O. Box 210203, Tucson, AZ 85721, United States
| | - J A Iddings
- Georgia Regents University, 1120 15th Street, Augusta, GA 30912, United States
| | - W Du
- Georgia Regents University, 1120 15th Street, Augusta, GA 30912, United States
| | - K J Kim
- Georgia Regents University, 1120 15th Street, Augusta, GA 30912, United States
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37
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Innervation of the arterial wall and its modification in atherosclerosis. Auton Neurosci 2015; 193:7-11. [DOI: 10.1016/j.autneu.2015.06.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2015] [Revised: 05/21/2015] [Accepted: 06/17/2015] [Indexed: 01/11/2023]
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Di Marco LY, Venneri A, Farkas E, Evans PC, Marzo A, Frangi AF. Vascular dysfunction in the pathogenesis of Alzheimer's disease--A review of endothelium-mediated mechanisms and ensuing vicious circles. Neurobiol Dis 2015; 82:593-606. [PMID: 26311408 DOI: 10.1016/j.nbd.2015.08.014] [Citation(s) in RCA: 190] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Revised: 07/23/2015] [Accepted: 08/17/2015] [Indexed: 12/17/2022] Open
Abstract
Late-onset dementia is a major health concern in the ageing population. Alzheimer's disease (AD) accounts for the largest proportion (65-70%) of dementia cases in the older population. Despite considerable research effort, the pathogenesis of late-onset AD remains unclear. Substantial evidence suggests that the neurodegenerative process is initiated by chronic cerebral hypoperfusion (CCH) caused by ageing and cardiovascular conditions. CCH causes reduced oxygen, glucose and other nutrient supply to the brain, with direct damage not only to the parenchymal cells, but also to the blood-brain barrier (BBB), a key mediator of cerebral homeostasis. BBB dysfunction mediates the indirect neurotoxic effects of CCH by promoting oxidative stress, inflammation, paracellular permeability, and dysregulation of nitric oxide, a key regulator of regional blood flow. As such, BBB dysfunction mediates a vicious circle in which cerebral perfusion is reduced further and the neurodegenerative process is accelerated. Endothelial interaction with pericytes and astrocytes could also play a role in the process. Reciprocal interactions between vascular dysfunction and neurodegeneration could further contribute to the development of the disease. A comprehensive overview of the complex scenario of interacting endothelium-mediated processes is currently lacking, and could prospectively contribute to the identification of adequate therapeutic interventions. This study reviews the current literature of in vitro and ex vivo studies on endothelium-mediated mechanisms underlying vascular dysfunction in AD pathogenesis, with the aim of presenting a comprehensive overview of the complex network of causative relationships. Particular emphasis is given to vicious circles which can accelerate the process of neurovascular degeneration.
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Affiliation(s)
- Luigi Yuri Di Marco
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, UK.
| | - Annalena Venneri
- Department of Neuroscience, Medical School, University of Sheffield, Sheffield, UK; IRCCS San Camillo Foundation Hospital, Venice, Italy
| | - Eszter Farkas
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Paul C Evans
- Department of Cardiovascular Science, Medical School, University of Sheffield, Sheffield, UK
| | - Alberto Marzo
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), Department of Mechanical Engineering, University of Sheffield, Sheffield, UK
| | - Alejandro F Frangi
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, UK
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Jellinger KA. Pathogenesis and treatment of vascular cognitive impairment. Neurodegener Dis Manag 2014; 4:471-90. [DOI: 10.2217/nmt.14.37] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
SUMMARY Vascular cognitive impairment (VCI) defines a continuum of disorders ranging from mild cognitive impairment to full-blown dementia, attributable to cerebrovascular causes. Major morphological types – multi-infarct encephalopathy, strategic infarct type, subcortical arteriosclerotic leukoencephalopathy, multilacunar state, postischemic encephalopathy – result from systemic, cardiac and local large or small vessel disease. Cognitive decline is commonly caused by widespread small cerebrovascular lesions (CVLs) affecting regions/networks essential for cognition, memory and behavior. CVLs often coexist with Alzheimer-type and other pathologies, which interact in promoting dementia, but in many nondemented elderly individuals, mixed brain pathologies are also present. Due to the high variability of CVLs, no validated clinical and neuropathological criteria for VCI are available. Cholinesterase inhibitors and memantine produce small cognitive improvement but without essential effect. Antihypertensive treatment, cardiovascular control and lifestyle modifications reducing vascular risk factors are essential. Given its growing health, social and economic burden, prevention and treatment of VCI are a major challenge of neuroscience.
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Chen BR, Kozberg MG, Bouchard MB, Shaik MA, Hillman EMC. A critical role for the vascular endothelium in functional neurovascular coupling in the brain. J Am Heart Assoc 2014; 3:e000787. [PMID: 24926076 PMCID: PMC4309064 DOI: 10.1161/jaha.114.000787] [Citation(s) in RCA: 235] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Background The functional modulation of blood flow in the brain is critical for brain health and is the basis of contrast in functional magnetic resonance imaging. There is evident coupling between increases in neuronal activity and increases in local blood flow; however, many aspects of this neurovascular coupling remain unexplained by current models. Based on the rapid dilation of distant pial arteries during cortical functional hyperemia, we hypothesized that endothelial signaling may play a key role in the long‐range propagation of vasodilation during functional hyperemia in the brain. Although well characterized in the peripheral vasculature, endothelial involvement in functional neurovascular coupling has not been demonstrated. Methods and Results We combined in vivo exposed‐cortex multispectral optical intrinsic signal imaging (MS‐OISI) with a novel in vivo implementation of the light‐dye technique to record the cortical hemodynamic response to somatosensory stimulus in rats before and after spatially selective endothelial disruption. We demonstrate that discrete interruption of endothelial signaling halts propagation of stimulus‐evoked vasodilation in pial arteries, and that wide‐field endothelial disruption in pial arteries significantly attenuates the hemodynamic response to stimulus, particularly the early, rapid increase and peak in hyperemia. Conclusions Involvement of endothelial pathways in functional neurovascular coupling provides new explanations for the spatial and temporal features of the hemodynamic response to stimulus and could explain previous results that were interpreted as evidence for astrocyte‐mediated control of functional hyperemia. Our results unify many aspects of blood flow regulation in the brain and body and prompt new investigation of direct links between systemic cardiovascular disease and neural deficits.
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Affiliation(s)
- Brenda R Chen
- Laboratory for Functional Optical Imaging, Departments of Biomedical Engineering and Radiology, Columbia University, New York, 10027, NY (B.R.C., M.G.K., M.B.B., M.A.S., E.C.H.)
| | - Mariel G Kozberg
- Laboratory for Functional Optical Imaging, Departments of Biomedical Engineering and Radiology, Columbia University, New York, 10027, NY (B.R.C., M.G.K., M.B.B., M.A.S., E.C.H.)
| | - Matthew B Bouchard
- Laboratory for Functional Optical Imaging, Departments of Biomedical Engineering and Radiology, Columbia University, New York, 10027, NY (B.R.C., M.G.K., M.B.B., M.A.S., E.C.H.)
| | - Mohammed A Shaik
- Laboratory for Functional Optical Imaging, Departments of Biomedical Engineering and Radiology, Columbia University, New York, 10027, NY (B.R.C., M.G.K., M.B.B., M.A.S., E.C.H.)
| | - Elizabeth M C Hillman
- Laboratory for Functional Optical Imaging, Departments of Biomedical Engineering and Radiology, Columbia University, New York, 10027, NY (B.R.C., M.G.K., M.B.B., M.A.S., E.C.H.)
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Impaired functional organization in the visual cortex of muscarinic receptor knock-out mice. Neuroimage 2014; 98:233-42. [PMID: 24837499 DOI: 10.1016/j.neuroimage.2014.05.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 04/09/2014] [Accepted: 05/07/2014] [Indexed: 11/21/2022] Open
Abstract
Acetylcholine modulates maturation and neuronal activity through muscarinic and nicotinic receptors in the primary visual cortex. However, the specific contribution of different muscarinic receptor subtypes in these neuromodulatory mechanisms is not fully understood. The present study evaluates in vivo the functional organization and the properties of the visual cortex of different groups of muscarinic receptor knock-out (KO) mice. Optical imaging of intrinsic signals coupled to continuous and episodic visual stimulation paradigms was used. Retinotopic maps along elevation and azimuth were preserved among the different groups of mice. However, compared to their wild-type counterparts, the apparent visual field along elevation was larger in M2/M4-KO mice but smaller in M1-KO. There was a reduction in the estimated relative receptive field size of V1 neurons in M1/M3-KO and M1-KO mice. Spatial frequency and contrast selectivity of V1 neuronal populations were affected only in M1/M3-KO and M1-KO mice. Finally, the neuronal connectivity was altered by the absence of M2/M4 muscarinic receptors. All these effects suggest the distinct roles of different subtypes of muscarinic receptors in the intrinsic organization of V1 and a strong involvement of the muscarinic transmission in the detectability of visual stimuli.
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Abstract
The basal forebrain cholinergic system modulates neuronal excitability and vascular tone throughout the cerebral cortex and hippocampus. This system is severely affected in Alzheimer's disease (AD), and drug treatment to enhance cholinergic signaling is widely used as symptomatic therapy in AD. Defining the full morphologies of individual basal forebrain cholinergic neurons has, until now, been technically beyond reach due to their large axon arbor sizes. Using genetically-directed sparse labeling, we have characterized the complete morphologies of basal forebrain cholinergic neurons in the mouse. Individual arbors were observed to span multiple cortical columns, and to have >1000 branch points and total axon lengths up to 50 cm. In an AD model, cholinergic axons were slowly lost and there was an accumulation of axon-derived material in discrete puncta. Calculations based on published morphometric data indicate that basal forebrain cholinergic neurons in humans have a mean axon length of ∼100 meters. DOI:http://dx.doi.org/10.7554/eLife.02444.001 The human brain is made up of roughly 80 to 100 billion neurons, organized into extensive networks. Each neuron consists of a number of components: a cell body, which contains the nucleus; numerous short protrusions from the cell body called dendrites; and a long thin structure called an axon that carries the electrical signals generated in the cell body and the dendrites to the next neuron in the network. One of the most studied networks in the human brain is the basal forebrain network, which is made up of large neurons that communicate with one another using a chemical transmitter called acetylcholine. This network has a key role in cognition, and its neurons are among the first to degenerate in Alzheimer's disease. However, relatively little is known about the structure of these ‘cholinergic’ neurons because their large size makes them difficult to study using standard techniques. Now, Wu et al. have visualized, for the first time, the complete 3D structure of cholinergic neurons in the mouse forebrain. The mice in question had been genetically modified so that only ten or so of their many thousands of cholinergic neurons expressed a distinctive ‘marker’ protein. This made it possible to distinguish these neurons from surrounding brain tissue in order to visualize their structures. The resulting pictures clearly illustrate the neurons' complexity, with individual axons in adult mice displaying up to 1000 branches. Measurements showed that each cholinergic axon in the mouse brain is roughly 30 centimeters long, even though the brain itself is less than 2 centimeters from front to back. Based on measurements by other researchers, Wu et al. calculated that the axons of single cholinergic neurons in the human brain are about 100 meters long on average. The extreme length and complex branching structure of cholinergic forebrain neurons helps to explain why each neuron is able to modulate the activity of many others in the network. It could also explain their vulnerability to degeneration, as the need to transport materials over such long distances may limit the ability of these neurons to respond to damage. DOI:http://dx.doi.org/10.7554/eLife.02444.002
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Affiliation(s)
- Hao Wu
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, United States
| | - John Williams
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Jeremy Nathans
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, United States Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States Department of Opthalmology, Johns Hopkins University School of Medicine, Baltimore, United States
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Willie CK, Tzeng YC, Fisher JA, Ainslie PN. Integrative regulation of human brain blood flow. J Physiol 2014; 592:841-59. [PMID: 24396059 PMCID: PMC3948549 DOI: 10.1113/jphysiol.2013.268953] [Citation(s) in RCA: 564] [Impact Index Per Article: 56.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 12/24/2013] [Indexed: 02/06/2023] Open
Abstract
Herein, we review mechanisms regulating cerebral blood flow (CBF), with specific focus on humans. We revisit important concepts from the older literature and describe the interaction of various mechanisms of cerebrovascular control. We amalgamate this broad scope of information into a brief review, rather than detailing any one mechanism or area of research. The relationship between regulatory mechanisms is emphasized, but the following three broad categories of control are explicated: (1) the effect of blood gases and neuronal metabolism on CBF; (2) buffering of CBF with changes in blood pressure, termed cerebral autoregulation; and (3) the role of the autonomic nervous system in CBF regulation. With respect to these control mechanisms, we provide evidence against several canonized paradigms of CBF control. Specifically, we corroborate the following four key theses: (1) that cerebral autoregulation does not maintain constant perfusion through a mean arterial pressure range of 60-150 mmHg; (2) that there is important stimulatory synergism and regulatory interdependence of arterial blood gases and blood pressure on CBF regulation; (3) that cerebral autoregulation and cerebrovascular sensitivity to changes in arterial blood gases are not modulated solely at the pial arterioles; and (4) that neurogenic control of the cerebral vasculature is an important player in autoregulatory function and, crucially, acts to buffer surges in perfusion pressure. Finally, we summarize the state of our knowledge with respect to these areas, outline important gaps in the literature and suggest avenues for future research.
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Affiliation(s)
- Christopher K Willie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada V1V 1V7.
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Kur J, Newman EA. Purinergic control of vascular tone in the retina. J Physiol 2014; 592:491-504. [PMID: 24277867 PMCID: PMC3930435 DOI: 10.1113/jphysiol.2013.267294] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 11/18/2013] [Indexed: 12/19/2022] Open
Abstract
Purinergic control of vascular tone in the CNS has been largely unexplored. This study examines the contribution of endogenous extracellular ATP, acting on vascular smooth muscle cells, in controlling vascular tone in the in vivo rat retina. Retinal vessels were labelled by i.v. injection of a fluorescent dye and imaged with scanning laser confocal microscopy. The diameters of primary arterioles were monitored under control conditions and following intravitreal injection of pharmacological agents. Apyrase (500 units ml(-1)), an ATP hydrolysing enzyme, dilated retinal arterioles by 40.4 ± 2.8%, while AOPCP (12.5 mm), an ecto-5'-nucleotidase inhibitor that increases extracellular ATP levels, constricted arterioles by 58.0 ± 3.8% (P < 0.001 for both), demonstrating the importance of ATP in the control of basal vascular tone. Suramin (500 μm), a broad-spectrum P2 receptor antagonist, dilated retinal arterioles by 50.9 ± 3.7% (P < 0.001). IsoPPADS (300 μm) and TNP-ATP (50 μm), more selective P2X antagonists, dilated arterioles by 41.0 ± 5.3% and 55.2 ± 6.1% respectively (P < 0.001 for both). NF023 (50 μm), a potent antagonist of P2X1 receptors, dilated retinal arterioles by 32.1 ± 2.6% (P < 0.001). A438079 (500 μm) and AZ10606120 (50 μm), P2X7 antagonists, had no effect on basal vascular tone (P = 0.99 and P = 1.00 respectively). In the ex vivo retina, the P2X1 receptor agonist α,β-methylene ATP (300 nm) evoked sustained vasoconstrictions of 18.7 ± 3.2% (P < 0.05). In vivo vitreal injection of the gliotoxin fluorocitrate (150 μm) dilated retinal vessels by 52.3 ± 1.1% (P < 0.001) and inhibited the vasodilatory response to NF023 (50 μm, 7.9 ± 2.0%; P < 0.01). These findings suggest that vascular tone in rat retinal arterioles is maintained by tonic release of ATP from the retina. ATP acts on P2X1 receptors, although contributions from other P2X and P2Y receptors cannot be ruled out. Retinal glial cells are a possible source of the vasoconstricting ATP.
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Affiliation(s)
- Joanna Kur
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA.
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Abstract
Rivastigmine is a second-generation cholinesterase inhibitor with selectivity for the CNS, with capacity to inhibit both acetylcholinesterase and butyrylcholinesterase. Rivastigmine is currently approved for the treatment of mild-to-moderate Alzheimer's disease. In addition to its effects on cognition and activities of daily living, rivastigmine appears to be useful in preventing and controlling behavioral and neuropsychiatric manifestations in Alzheimer's disease and dementia with Lewy bodies. This drug profile could be potentially useful in patients with subcortical vascular dementia who often present these symptoms. Small open-label studies of patients with subcortical vascular dementia showed that rivastigmine improved attention, executive function, apathy and other behavioral deficits. Rivastigmine appears to be a promising agent in vascular dementia but its effects remain to be established in double-blind, placebo-controlled clinical trials.
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Affiliation(s)
- Gustavo C Román
- University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, Mail Code 7883, San Antonio, TX 78229 3900, USA.
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Cadotte DW, Cohen-Adad J, Fehlings MG. Visualizing Integrative Functioning in the Human Brainstem and Spinal Cord With Spinal Functional Magnetic Resonance Imaging. Neurosurgery 2013; 60 Suppl 1:102-9. [DOI: 10.1227/01.neu.0000430767.87725.95] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Abstract
Cerebral blood flow is controlled by two crucial processes, cerebral autoregulation (CA) and neurovascular coupling (NVC) or functional hyperemia. Whereas CA ensures constant blood flow over a wide range of systemic pressures, NVC ensures rapid spatial and temporal increases in cerebral blood flow in response to neuronal activation. The focus of this review is to discuss the cellular mechanisms by which astrocytes contribute to the regulation of vascular tone in terms of their participation in NVC and, to a lesser extent, CA. We discuss evidence for the various signaling modalities by which astrocytic activation leads to vasodilation and vasoconstriction of parenchymal arterioles. Moreover, we provide a rationale for the contribution of astrocytes to pressure-induced increases in vascular tone via the vasoconstrictor 20-HETE (a downstream metabolite of arachidonic acid). Along these lines, we highlight the importance of the transient receptor potential channel of the vanilloid family (TRPV4) as a key molecular determinant in the regulation of vascular tone in cerebral arterioles. Finally, we discuss current advances in the technical tools available to study NVC mechanisms in the brain as it relates to the participation of astrocytes.
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Jellinger KA. Pathology and pathogenesis of vascular cognitive impairment-a critical update. Front Aging Neurosci 2013; 5:17. [PMID: 23596414 PMCID: PMC3622231 DOI: 10.3389/fnagi.2013.00017] [Citation(s) in RCA: 205] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 03/24/2013] [Indexed: 12/21/2022] Open
Abstract
Vascular cognitive impairment (VCI) [vascular cognitive disorder (VCD), vascular dementia] describes a continuum of cognitive disorders ranging from mild cognitive impairment (MCI) to dementia, in which vascular brain injury involving regions important for memory, cognition and behavior plays an important role. Clinical diagnostic criteria show moderate sensitivity (ca 50%) and variable specificity (range 64-98%). In Western clinical series, VaD is suggested in 8-10% of cognitively impaired elderly subjects. Its prevalence in autopsy series varies from 0.03 to 58%, with means of 8 to 15% (in Japan 22-35%). Major types of sporadic VaD are multi-infarct encephalopathy, small vessel and strategic infarct type dementias, subcortical arteriosclerotic leukoencephalopathy (SAE) (Binswanger), multilacunar state, mixed cortico-subcortical type, granular cortical atrophy (rare), postischemic encephalopathy, and a mixture of cerebrovascular lesions (CVLs). They result from systemic, cardiac and local large or small vessel disease (SVD); their pathogenesis is multifactorial. Hereditary forms of VaD caused by gene mutations are rare. Cognitive decline is commonly associated with widespread small ischemic vascular lesions involving subcortical brain areas (basal ganglia and hemispheral white matter). The lesions affect neuronal networks involved in cognition, memory, and behavior (thalamo-cortical, striato-subfrontal, cortico-subcortical, limbic systems). CVLs often coexist with Alzheimer-type lesions and other pathologies; 25-80% of elderly demented show mixed pathologies. The lesion pattern of "pure" VaD differs from that in mixed dementia (AD + CVLs) suggesting different pathogenesis of both phenotypes. Minor CVLs, except for severe amyloid angiopathy, appear not essential for cognitive impairment in full-blown AD, while both mild AD-type pathology and SVD may interact synergistically in promoting dementia. However, in a large percentage of non-demented elderly individuals, both AD-related and vascular brain pathologies have been reported. Despite recent suggestions for staging and grading CVLs in specific brain areas, due to the high variability of CVLs associated with cognitive impairment, no validated neuropathological criteria are currently available for VaD and mixed dementia. Further clinico-pathological studies and harmonization of neuropathological procedures are needed to validate the diagnostic criteria for VaD and mixed dementia in order to clarify the impact of CVLs and other coexistent pathologies on cognitive impairment as a basis for further successful therapeutic options.
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Affiliation(s)
- Kurt A. Jellinger
- Institute of Clinical Neurobiology, Medical University of ViennaVienna, Austria
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Furey ML, Drevets WC, Hoffman EM, Frankel E, Speer AM, Zarate CA. Potential of pretreatment neural activity in the visual cortex during emotional processing to predict treatment response to scopolamine in major depressive disorder. JAMA Psychiatry 2013; 70:280-90. [PMID: 23364679 PMCID: PMC3717361 DOI: 10.1001/2013.jamapsychiatry.60] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
CONTEXT The need for improved treatment options for patients with major depressive disorder (MDD) is critical. Faster-acting antidepressants and biomarkers that predict clinical response will facilitate treatment. Scopolamine produces rapid antidepressant effects and thus offers the opportunity to characterize potential biomarkers of treatment response within short periods. OBJECTIVE To determine if baseline brain activity when processing emotional information can predict treatment response to scopolamine in MDD. DESIGN A double-blind, placebo-controlled, crossover study together with repeated functional magnetic resonance imaging, acquired as participants performed face-identity and face-emotion working memory tasks. SETTING National Institute of Mental Health Division of Intramural Research Programs. PARTICIPANTS Fifteen currently depressed outpatients meeting DSM-IV criteria for recurrent MDD and 21 healthy participants, between 18 and 55 years of age. MAIN OUTCOME MEASURE The magnitude of treatment response to scopolamine (percentage of change in the Montgomery-Asberg Depression Rating Scale score between study end and baseline) was correlated with blood oxygen level-dependent (BOLD) signal associated with each working memory component (encode, maintenance, and test) for both identity and emotion tasks. Treatment response also was correlated with change in BOLD response (scopolamine vs baseline). Baseline activity was compared between healthy and MDD groups. RESULTS Baseline BOLD response in the bilateral middle occipital cortex, selectively during the stimulus-processing components of the emotion working memory task (no correlation during the identity task), correlated with treatment response magnitude. Change in BOLD response following scopolamine administration in overlapping areas in the middle occipital cortex while performing the same task conditions also correlated with clinical response. Healthy controls showed higher activity in the same visual regions than patients with MDD during baseline. CONCLUSION These results implicate cholinergic and visual processing dysfunction in the pathophysiology of MDD and suggest that neural response in the visual cortex, selectively to emotional stimuli, may provide a useful biomarker for identifying patients who will respond favorably to scopolamine. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00055575.
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Affiliation(s)
- Maura L Furey
- Experimental Therapeutics and Pathophysiology Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Electroacupuncture acutely improves cerebral blood flow and attenuates moderate ischemic injury via an endothelial mechanism in mice. PLoS One 2013; 8:e56736. [PMID: 23418594 PMCID: PMC3572074 DOI: 10.1371/journal.pone.0056736] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 01/14/2013] [Indexed: 11/19/2022] Open
Abstract
Electroacupuncture (EA) is a novel therapy based on traditional acupuncture combined with modern eletrotherapy that is currently being investigated as a treatment for acute ischemic stroke. Here, we studied whether acute EA stimulation improves tissue and functional outcome following experimentally induced cerebral ischemia in mice. We hypothesized that endothelial nitric oxide synthase (eNOS)-mediated perfusion augmentation was related to the beneficial effects of EA by interventions in acute ischemic injury. EA stimulation at Baihui (GV20) and Dazhui (GV14) increased cerebral perfusion in the cerebral cortex, which was suppressed in eNOS KO, but there was no mean arterial blood pressure (MABP) response. The increased perfusion elicited by EA were completely abolished by a muscarinic acetylcholine receptor (mAChR) blocker (atropine), but not a β-adrenergic receptor blocker (propranolol), an α-adrenergic receptor blocker (phentolamine), or a nicotinic acetylcholine receptor (nAChR) blocker (mecamylamine). In addition, EA increased acetylcholine (ACh) release and mAChR M3 expression in the cerebral cortex. Acute EA stimulation after occlusion significantly reduced infarct volume by 34.5% when compared to a control group of mice at 24 h after 60 min-middle cerebral artery occlusion (MCAO) (moderate ischemic injury), but not 90-min MCAO (severe ischemic injury). Furthermore, the impact of EA on moderate ischemic injury was totally abolished in eNOS KO. Consistent with a smaller infarct size, acute EA stimulation led to prominent improvement of neurological function and vestibule-motor function. Our results suggest that acute EA stimulation after moderate focal cerebral ischemia, but not severe ischemia improves tissue and functional recovery and ACh/eNOS-mediated perfusion augmentation might be related to these beneficial effects of EA by interventions in acute ischemic injury.
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