51
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Finger CE, Moreno-Gonzalez I, Gutierrez A, Moruno-Manchon JF, McCullough LD. Age-related immune alterations and cerebrovascular inflammation. Mol Psychiatry 2022; 27:803-818. [PMID: 34711943 PMCID: PMC9046462 DOI: 10.1038/s41380-021-01361-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 09/20/2021] [Accepted: 10/12/2021] [Indexed: 12/11/2022]
Abstract
Aging is associated with chronic systemic inflammation, which contributes to the development of many age-related diseases, including vascular disease. The world's population is aging, leading to an increasing prevalence of both stroke and vascular dementia. The inflammatory response to ischemic stroke is critical to both stroke pathophysiology and recovery. Age is a predictor of poor outcomes after stroke. The immune response to stroke is altered in aged individuals, which contributes to the disparate outcomes between young and aged patients. In this review, we describe the current knowledge of the effects of aging on the immune system and the cerebral vasculature and how these changes alter the immune response to stroke and vascular dementia in animal and human studies. Potential implications of these age-related immune alterations on chronic inflammation in vascular disease outcome are highlighted.
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Affiliation(s)
- Carson E. Finger
- Department of Neurology, McGovern Medical School, UTHealth Science Center at Houston, Houston, TX USA
| | - Ines Moreno-Gonzalez
- Department of Neurology, McGovern Medical School, UTHealth Science Center at Houston, Houston, TX USA ,grid.10215.370000 0001 2298 7828Department of Cell Biology, Genetics and Physiology, Instituto de Investigacion Biomedica de Malaga-IBIMA, Faculty of Sciences, Malaga University, Malaga, Spain ,grid.418264.d0000 0004 1762 4012Biomedical Research Networking Center on Neurodegenerative Diseases (CIBERNED), Malaga, Spain
| | - Antonia Gutierrez
- grid.10215.370000 0001 2298 7828Department of Cell Biology, Genetics and Physiology, Instituto de Investigacion Biomedica de Malaga-IBIMA, Faculty of Sciences, Malaga University, Malaga, Spain ,grid.418264.d0000 0004 1762 4012Biomedical Research Networking Center on Neurodegenerative Diseases (CIBERNED), Malaga, Spain
| | - Jose Felix Moruno-Manchon
- Department of Neurology, McGovern Medical School, UTHealth Science Center at Houston, Houston, TX USA
| | - Louise D. McCullough
- Department of Neurology, McGovern Medical School, UTHealth Science Center at Houston, Houston, TX USA
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52
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Hu Y, Tao W. Microenvironmental Variations After Blood-Brain Barrier Breakdown in Traumatic Brain Injury. Front Mol Neurosci 2021; 14:750810. [PMID: 34899180 PMCID: PMC8662751 DOI: 10.3389/fnmol.2021.750810] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Accepted: 10/18/2021] [Indexed: 12/12/2022] Open
Abstract
Traumatic brain injury (TBI) is linked to several pathologies. The blood-brain barrier (BBB) breakdown is considered to be one of the initial changes. Further, the microenvironmental alteration following TBI-induced BBB breakdown can be multi-scaled, constant, and dramatic. The microenvironmental variations after disruption of BBB includes several pathological changes, such as cerebral blood flow (CBF) alteration, brain edema, cerebral metabolism imbalances, and accumulation of inflammatory molecules. The modulation of the microenvironment presents attractive targets for TBI recovery, such as reducing toxic substances, inhibiting inflammation, and promoting neurogenesis. Herein, we briefly review the pathological alterations of the microenvironmental changes following BBB breakdown and outline potential interventions for TBI recovery based on microenvironmental modulation.
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Affiliation(s)
- Yue Hu
- School of Chinese Medicine, School of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Weiwei Tao
- School of Chinese Medicine, School of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, China.,Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Nanjing University of Chinese Medicine, Nanjing, China
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53
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Ivanova E, Corona C, Eleftheriou CG, Stout RF, Körbelin J, Sagdullaev BT. AAV-BR1 targets endothelial cells in the retina to reveal their morphological diversity and to deliver Cx43. J Comp Neurol 2021; 530:1302-1317. [PMID: 34811744 DOI: 10.1002/cne.25277] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 11/13/2021] [Accepted: 11/16/2021] [Indexed: 12/15/2022]
Abstract
Endothelial cells (ECs) are key players in the development and maintenance of the vascular tree, the establishment of the blood-brain barrier and control of blood flow. Disruption in ECs is an early and active component of vascular pathogenesis. However, our ability to selectively target ECs in the CNS for identification and manipulation is limited. Here, in the mouse retina, a tractable model of the CNS, we utilized a recently developed AAV-BR1 system to identify distinct classes of ECs along the vascular tree using a GFP reporter. We then developed an inducible EC-specific ectopic Connexin 43 (Cx43) expression system using AAV-BR1-CAG-DIO-Cx43-P2A-DsRed2 in combination with a mouse line carrying inducible CreERT2 in ECs. We targeted Cx43 because its loss has been implicated in microvascular impairment in numerous diseases such as diabetic retinopathy and vascular edema. GFP-labeled ECs were numerous, evenly distributed along the vascular tree and their morphology was polarized with respect to the direction of blood flow. After tamoxifen induction, ectopic Cx43 was specifically expressed in ECs. Similarly to endogenous Cx43, ectopic Cx43 was localized at the membrane contacts of ECs and it did not affect tight junction proteins. The ability to enhance gap junctions in ECs provides a precise and potentially powerful tool to treat microcirculation deficits, an early pathology in numerous diseases.
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Affiliation(s)
- Elena Ivanova
- Burke Neurological Institute, White Plains, New York, USA.,Brain and Mind Research Institute, Weill Cornell Medicine, White Plains, New York, USA
| | - Carlo Corona
- Burke Neurological Institute, White Plains, New York, USA
| | | | - Randy F Stout
- Department of Biomedical Sciences, The New York Institute of Technology College of Osteopathic Medicine, Old Westbury, New York, USA
| | - Jakob Körbelin
- Department of Oncology, Hematology, and Bone Marrow Transplantation, University Medical Center Hamburg-Eppendorf, Hamburg, USA
| | - Botir T Sagdullaev
- Burke Neurological Institute, White Plains, New York, USA.,Brain and Mind Research Institute, Weill Cornell Medicine, White Plains, New York, USA.,Department of Ophthalmology, Weill Cornell Medicine, White Plains, New York, USA
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54
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Hakim MA, Behringer EJ. Methyl-Beta-Cyclodextrin Restores K IR Channel Function in Brain Endothelium of Female Alzheimer's Disease Mice. J Alzheimers Dis Rep 2021; 5:693-703. [PMID: 34755043 PMCID: PMC8543374 DOI: 10.3233/adr-210016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/09/2021] [Indexed: 12/12/2022] Open
Abstract
Background: As the sixth-leading cause of death in the United States, Alzheimer’s disease (AD) entails deteriorating endothelial control of blood flow throughout the brain. In particular, reduced inward-rectifying K+ (KIR) channel function in animal models of aging and AD compromises endothelial function and optimal perfusion of brain parenchyma. Deficient endothelial KIR channels may result from aberrant interaction with plasma membrane cholesterol as a primary regulator of membrane fluidity and ion channels. Objective: We tested the hypothesis that mild methyl-β-cyclodextrin (MβCD) treatment to reduce membrane cholesterol may restore endothelial KIR channel function in brain endothelium of old AD mice. Methods: Membrane potential was continuously measured in isolated endothelial tubes from posterior cerebral arteries of young (1 to 3 months) and old (16 to 19 months) female 3xTg-AD mice before and after mild treatment with the cholesterol-removing agent MβCD (1 mmol/L). Elevated extracellular potassium ([K+]E; 15 mmol/L) and NS309 (1μmol/L) activated KIR and Ca2+-activated K+ (SKCa/IKCa) channels respectively before and after MβCD treatment. Results: SKCa/IKCa channel function for producing hyperpolarization remained stable regardless of age group and MβCD treatment (ΔVm: ∼–33 mV). However, as deficient during AD, KIR channel function was restored (ΔVm: –9±1 mV) versus pre-MβCD conditions (–5±1 mV); a progressive effect that reached –14±1 mV hyperpolarization at 60 min following MβCD washout. Conclusion: In female animals, MβCD treatment of brain endothelium selectively restores KIR versus SKCa/IKCa channel function during AD. Thus, the endothelial cholesterol-KIR channel interface is a novel target for ameliorating perfusion of the AD brain.
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Affiliation(s)
- Md A Hakim
- Basic Sciences, Loma Linda University, Loma Linda, CA, USA
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55
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Lourenço CF, Laranjinha J. Nitric Oxide Pathways in Neurovascular Coupling Under Normal and Stress Conditions in the Brain: Strategies to Rescue Aberrant Coupling and Improve Cerebral Blood Flow. Front Physiol 2021; 12:729201. [PMID: 34744769 PMCID: PMC8569710 DOI: 10.3389/fphys.2021.729201] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 09/20/2021] [Indexed: 01/04/2023] Open
Abstract
The brain has impressive energy requirements and paradoxically, very limited energy reserves, implying its huge dependency on continuous blood supply. Aditionally, cerebral blood flow must be dynamically regulated to the areas of increased neuronal activity and thus, of increased metabolic demands. The coupling between neuronal activity and cerebral blood flow (CBF) is supported by a mechanism called neurovascular coupling (NVC). Among the several vasoactive molecules released by glutamatergic activation, nitric oxide (•NO) is recognized to be a key player in the process and essential for the development of the neurovascular response. Classically, •NO is produced in neurons upon the activation of the glutamatergic N-methyl-D-aspartate (NMDA) receptor by the neuronal isoform of nitric oxide synthase and promotes vasodilation by activating soluble guanylate cyclase in the smooth muscle cells of the adjacent arterioles. This pathway is part of a more complex network in which other molecular and cellular intervenients, as well as other sources of •NO, are involved. The elucidation of these interacting mechanisms is fundamental in understanding how the brain manages its energy requirements and how the failure of this process translates into neuronal dysfunction. Here, we aimed to provide an integrated and updated perspective of the role of •NO in the NVC, incorporating the most recent evidence that reinforces its central role in the process from both viewpoints, as a physiological mediator and a pathological stressor. First, we described the glutamate-NMDA receptor-nNOS axis as a central pathway in NVC, then we reviewed the link between the derailment of the NVC and neuronal dysfunction associated with neurodegeneration (with a focus on Alzheimer's disease). We further discussed the role of oxidative stress in the NVC dysfunction, specifically by decreasing the •NO bioavailability and diverting its bioactivity toward cytotoxicity. Finally, we highlighted some strategies targeting the rescue or maintenance of •NO bioavailability that could be explored to mitigate the NVC dysfunction associated with neurodegenerative conditions. In line with this, the potential modulatory effects of dietary nitrate and polyphenols on •NO-dependent NVC, in association with physical exercise, may be used as effective non-pharmacological strategies to promote the •NO bioavailability and to manage NVC dysfunction in neuropathological conditions.
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Affiliation(s)
- Cátia F Lourenço
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - João Laranjinha
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
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56
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Valenzuela F, Rana M, Sitaram R, Uribe S, Eblen-Zajjur A. Non-Invasive Functional Evaluation of the Human Spinal Cord by Assessing the Peri-Spinal Neurovascular Network With Near Infrared Spectroscopy. IEEE Trans Neural Syst Rehabil Eng 2021; 29:2312-2321. [PMID: 34705650 DOI: 10.1109/tnsre.2021.3123587] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Current medical care lacks an effective functional evaluation for the spinal cord. Magnetic resonance imaging and computed tomography mainly provide structural information of the spinal cord, while spinal somatosensory evoked potentials are limited by a low signal to noise ratio. We developed a non-invasive approach based on near-infrared spectroscopy in dual-wavelength (760 and 850 nm for deoxy- or oxyhemoglobin respectively) to record the neurovascular response (NVR) of the peri-spinal vascular network at the 7th cervical and 10th thoracic vertebral levels of the spinal cord, triggered by unilateral median nerve electrical stimulation (square pulse, 5-10 mA, 5 ms, 1 pulse every 4 minutes) at the wrist. Amplitude, rise-time, and duration of NVR were characterized in 20 healthy participants. A single, painless stimulus was able to elicit a high signal-to-noise ratio and multi-segmental NVR (mainly from Oxyhemoglobin) with a fast rise time of 6.18 [4.4-10.4] seconds (median [Percentile 25-75]) followed by a slow decay phase for about 30 seconds toward the baseline. Cervical NVR was earlier and larger than thoracic and no left/right asymmetry was detected. Stimulus intensity/NVR amplitude fitted to a 2nd order function. The characterization and feasibility of the peri-spinal NVR strongly support the potential clinical applications for a functional assessment of spinal cord lesions.
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57
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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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58
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Claassen JAHR, Thijssen DHJ, Panerai RB, Faraci FM. Regulation of cerebral blood flow in humans: physiology and clinical implications of autoregulation. Physiol Rev 2021; 101:1487-1559. [PMID: 33769101 PMCID: PMC8576366 DOI: 10.1152/physrev.00022.2020] [Citation(s) in RCA: 289] [Impact Index Per Article: 96.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Brain function critically depends on a close matching between metabolic demands, appropriate delivery of oxygen and nutrients, and removal of cellular waste. This matching requires continuous regulation of cerebral blood flow (CBF), which can be categorized into four broad topics: 1) autoregulation, which describes the response of the cerebrovasculature to changes in perfusion pressure; 2) vascular reactivity to vasoactive stimuli [including carbon dioxide (CO2)]; 3) neurovascular coupling (NVC), i.e., the CBF response to local changes in neural activity (often standardized cognitive stimuli in humans); and 4) endothelium-dependent responses. This review focuses primarily on autoregulation and its clinical implications. To place autoregulation in a more precise context, and to better understand integrated approaches in the cerebral circulation, we also briefly address reactivity to CO2 and NVC. In addition to our focus on effects of perfusion pressure (or blood pressure), we describe the impact of select stimuli on regulation of CBF (i.e., arterial blood gases, cerebral metabolism, neural mechanisms, and specific vascular cells), the interrelationships between these stimuli, and implications for regulation of CBF at the level of large arteries and the microcirculation. We review clinical implications of autoregulation in aging, hypertension, stroke, mild cognitive impairment, anesthesia, and dementias. Finally, we discuss autoregulation in the context of common daily physiological challenges, including changes in posture (e.g., orthostatic hypotension, syncope) and physical activity.
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Affiliation(s)
- Jurgen A H R Claassen
- Department of Geriatrics, Radboud University Medical Center, Donders Institute for Brain, Cognition, and Behaviour, Nijmegen, The Netherlands
| | - Dick H J Thijssen
- Department of Physiology, Radboud Institute for Health Sciences, Nijmegen, The Netherlands
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- >National Institute for Health Research Leicester Biomedical Research Centre, University of Leicester, Leicester, United Kingdom
| | - Frank M Faraci
- Departments of Internal Medicine, Neuroscience, and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, Iowa
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59
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Abstract
The cerebral microcirculation undergoes dynamic changes in parallel with the development of neurons, glia, and their energy metabolism throughout gestation and postnatally. Cerebral blood flow (CBF), oxygen consumption, and glucose consumption are as low as 20% of adult levels in humans born prematurely but eventually exceed adult levels at ages 3 to 11 years, which coincide with the period of continued brain growth, synapse formation, synapse pruning, and myelination. Neurovascular coupling to sensory activation is present but attenuated at birth. By 2 postnatal months, the increase in CBF often is disproportionately smaller than the increase in oxygen consumption, in contrast to the relative hyperemia seen in adults. Vascular smooth muscle myogenic tone increases in parallel with developmental increases in arterial pressure. CBF autoregulatory response to increased arterial pressure is intact at birth but has a more limited range with arterial hypotension. Hypoxia-induced vasodilation in preterm fetal sheep with low oxygen consumption does not sustain cerebral oxygen transport, but the response becomes better developed for sustaining oxygen transport by term. Nitric oxide tonically inhibits vasomotor tone, and glutamate receptor activation can evoke its release in lambs and piglets. In piglets, astrocyte-derived carbon monoxide plays a central role in vasodilation evoked by glutamate, ADP, and seizures, and prostanoids play a large role in endothelial-dependent and hypercapnic vasodilation. Overall, homeostatic mechanisms of CBF regulation in response to arterial pressure, neuronal activity, carbon dioxide, and oxygenation are present at birth but continue to develop postnatally as neurovascular signaling pathways are dynamically altered and integrated. © 2021 American Physiological Society. Compr Physiol 11:1-62, 2021.
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60
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Imaging faster neural dynamics with fast fMRI: A need for updated models of the hemodynamic response. Prog Neurobiol 2021; 207:102174. [PMID: 34525404 DOI: 10.1016/j.pneurobio.2021.102174] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 07/30/2021] [Accepted: 09/08/2021] [Indexed: 12/20/2022]
Abstract
Fast fMRI enables the detection of neural dynamics over timescales of hundreds of milliseconds, suggesting it may provide a new avenue for studying subsecond neural processes in the human brain. The magnitudes of these fast fMRI dynamics are far greater than predicted by canonical models of the hemodynamic response. Several studies have established nonlinear properties of the hemodynamic response that have significant implications for fast fMRI. We first review nonlinear properties of the hemodynamic response function that may underlie fast fMRI signals. We then illustrate the breakdown of canonical hemodynamic response models in the context of fast neural dynamics. We will then argue that the canonical hemodynamic response function is not likely to reflect the BOLD response to neuronal activity driven by sparse or naturalistic stimuli or perhaps to spontaneous neuronal fluctuations in the resting state. These properties suggest that fast fMRI is capable of tracking surprisingly fast neuronal dynamics, and we discuss the neuroscientific questions that could be addressed using this approach.
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61
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Schaeffer S, Iadecola C. Revisiting the neurovascular unit. Nat Neurosci 2021; 24:1198-1209. [PMID: 34354283 PMCID: PMC9462551 DOI: 10.1038/s41593-021-00904-7] [Citation(s) in RCA: 235] [Impact Index Per Article: 78.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 06/30/2021] [Indexed: 02/06/2023]
Abstract
The brain is supplied by an elaborate vascular network that originates extracranially and reaches deep into the brain. The concept of the neurovascular unit provides a useful framework to investigate how neuronal signals regulate nearby microvessels to support the metabolic needs of the brain, but it does not consider the role of larger cerebral arteries and systemic vasoactive signals. Furthermore, the recently emerged molecular heterogeneity of cerebrovascular cells indicates that there is no prototypical neurovascular unit replicated at all levels of the vascular network. Here, we examine the cellular and molecular diversity of the cerebrovascular tree and the relative contribution of systemic and brain-intrinsic factors to neurovascular function. Evidence supports the concept of a 'neurovascular complex' composed of segmentally diverse functional modules that implement coordinated vascular responses to central and peripheral signals to maintain homeostasis of the brain. This concept has major implications for neurovascular regulation in health and disease and for brain imaging.
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62
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Treatment with the BCL-2/BCL-xL inhibitor senolytic drug ABT263/Navitoclax improves functional hyperemia in aged mice. GeroScience 2021; 43:2427-2440. [PMID: 34427858 PMCID: PMC8599595 DOI: 10.1007/s11357-021-00440-z] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 08/11/2021] [Indexed: 12/13/2022] Open
Abstract
Moment-to-moment adjustment of regional cerebral blood flow to neuronal activity via neurovascular coupling (NVC or "functional hyperemia") has a critical role in maintenance of healthy cognitive function. Aging-induced impairment of NVC responses importantly contributes to age-related cognitive decline. Advanced aging is associated with increased prevalence of senescent cells in the cerebral microcirculation, but their role in impaired NVC responses remains unexplored. The present study was designed to test the hypothesis that a validated senolytic treatment can improve NVC responses and cognitive performance in aged mice. To achieve this goal, aged (24-month-old) C57BL/6 mice were treated with ABT263/Navitoclax, a potent senolytic agent known to eliminate senescent cells in the aged mouse brain. Mice were behaviorally evaluated (radial arms water maze) and NVC was assessed by measuring CBF responses (laser speckle contrast imaging) in the somatosensory whisker barrel cortex evoked by contralateral whisker stimulation. We found that NVC responses were significantly impaired in aged mice. ABT263/Navitoclax treatment improved NVC response, which was associated with significantly improved hippocampal-encoded functions of learning and memory. ABT263/Navitoclax treatment did not significantly affect endothelium-dependent acetylcholine-induced relaxation of aorta rings. Thus, increased presence of senescent cells in the aged brain likely contributes to age-related neurovascular uncoupling, exacerbating cognitive decline. The neurovascular protective effects of ABT263/Navitoclax treatment highlight the preventive and therapeutic potential of senolytic treatments (as monotherapy or as part of combination treatment regimens) as effective interventions in patients at risk for vascular cognitive impairment (VCI).
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63
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Rosehart AC, Longden TA, Weir N, Fontaine JT, Joutel A, Dabertrand F. Prostaglandin E 2 Dilates Intracerebral Arterioles When Applied to Capillaries: Implications for Small Vessel Diseases. Front Aging Neurosci 2021; 13:695965. [PMID: 34483880 PMCID: PMC8414797 DOI: 10.3389/fnagi.2021.695965] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 06/15/2021] [Indexed: 11/24/2022] Open
Abstract
Prostaglandin E2 (PGE2) has been widely proposed to mediate neurovascular coupling by dilating brain parenchymal arterioles through activation of prostanoid EP4 receptors. However, our previous report that direct application of PGE2 induces an EP1-mediated constriction strongly argues against its direct action on arterioles during neurovascular coupling, the mechanisms sustaining functional hyperemia. Recent advances have highlighted the role of capillaries in sensing neuronal activity and propagating vasodilatory signals to the upstream penetrating parenchymal arteriole. Here, we examined the effect of capillary stimulation with PGE2 on upstream arteriolar diameter using an ex vivo capillary-parenchymal arteriole preparation and in vivo cerebral blood flow measurements with two-photon laser-scanning microscopy. We found that PGE2 caused upstream arteriolar dilation when applied onto capillaries with an EC50 of 70 nM. The response was inhibited by EP1 receptor antagonist and was greatly reduced, but not abolished, by blocking the strong inward-rectifier K+ channel. We further observed a blunted dilatory response to capillary stimulation with PGE2 in a genetic mouse model of cerebral small vessel disease with impaired functional hyperemia. This evidence casts previous findings in a different light, indicating that capillaries are the locus of PGE2 action to induce upstream arteriolar dilation in the control of brain blood flow, thereby providing a paradigm-shifting view that nonetheless remains coherent with the broad contours of a substantial body of existing literature.
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Affiliation(s)
- Amanda C. Rosehart
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Thomas A. Longden
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, Baltimore, MD, United States
| | - Nick Weir
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, Baltimore, MD, United States
| | - Jackson T. Fontaine
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Anne Joutel
- INSERM, UMR 1266, GHU Paris Psychiatrie et Neurosciences, Institute of Psychiatry and Neuroscience of Paris, University of Paris, Paris, France
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, VT, United States
| | - Fabrice Dabertrand
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Department of Pharmacology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
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64
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Tarantini S, Nyúl-Tóth Á, Yabluchanskiy A, Csipo T, Mukli P, Balasubramanian P, Ungvari A, Toth P, Benyo Z, Sonntag WE, Ungvari Z, Csiszar A. Endothelial deficiency of insulin-like growth factor-1 receptor (IGF1R) impairs neurovascular coupling responses in mice, mimicking aspects of the brain aging phenotype. GeroScience 2021; 43:2387-2394. [PMID: 34383203 PMCID: PMC8599783 DOI: 10.1007/s11357-021-00405-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 06/15/2021] [Indexed: 11/27/2022] Open
Abstract
Age-related impairment of neurovascular coupling (NVC; or "functional hyperemia") compromises moment-to-moment adjustment of regional cerebral blood flow to increased neuronal activity and thereby contributes to the pathogenesis of vascular cognitive impairment (VCI). Previous studies established a causal link among age-related decline in circulating levels of insulin-like growth factor-1 (IGF-1), neurovascular dysfunction and cognitive impairment. Endothelium-mediated microvascular dilation plays a central role in NVC responses. To determine the functional consequences of impaired IGF-1 input to cerebromicrovascular endothelial cells, endothelium-mediated NVC responses were studied in a novel mouse model of accelerated neurovascular aging: mice with endothelium-specific knockout of IGF1R (VE-Cadherin-CreERT2/Igf1rf/f). Increases in cerebral blood flow in the somatosensory whisker barrel cortex (assessed using laser speckle contrast imaging through a cranial window) in response to contralateral whisker stimulation were significantly attenuated in VE-Cadherin-CreERT2/Igf1rf/f mice as compared to control mice. In VE-Cadherin-CreERT2/Igf1rf/f mice, the effects of the NO synthase inhibitor L-NAME were significantly decreased, suggesting that endothelium-specific disruption of IGF1R signaling impairs the endothelial NO-dependent component of NVC responses. Collectively, these findings provide additional evidence that IGF-1 is critical for cerebromicrovascular endothelial health and maintenance of normal NVC responses.
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Affiliation(s)
- Stefano Tarantini
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 731042, USA
- International Training Program in Geroscience, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 731042, USA
- Peggy and Charles Stephenson Cancer Center, Oklahoma City, OK, 73104, USA
- Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary
| | - Ádám Nyúl-Tóth
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 731042, USA
- International Training Program in Geroscience, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 731042, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary
- International Training Program in Geroscience, Institute of Biophysics, Biological Research Centre, Eötvös Loránd Research Network (ELKH), Szeged, Hungary
| | - Andriy Yabluchanskiy
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 731042, USA
- International Training Program in Geroscience, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 731042, USA
- Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Tamas Csipo
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 731042, USA
- International Training Program in Geroscience, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 731042, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary
| | - Peter Mukli
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 731042, USA
- International Training Program in Geroscience, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 731042, USA
- International Training Program in Geroscience, Department of Physiology, Semmelweis University, Budapest, Hungary
| | - Priya Balasubramanian
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 731042, USA
| | - Anna Ungvari
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 731042, USA
| | - Peter Toth
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary
- Department of Neurosurgery, University of Pécs Clinical Center, 72359, Pecs, Baranya, Hungary
| | - Zoltan Benyo
- Vascular Cognitive Impairment and Neurodegeneration Program, Department of Translational Medicine, Semmelweis University, Budapest, Hungary
| | - William E Sonntag
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 731042, USA
| | - Zoltan Ungvari
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 731042, USA
- International Training Program in Geroscience, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 731042, USA
- Peggy and Charles Stephenson Cancer Center, Oklahoma City, OK, 73104, USA
- Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary
| | - Anna Csiszar
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 731042, USA.
- International Training Program in Geroscience, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 731042, USA.
- Peggy and Charles Stephenson Cancer Center, Oklahoma City, OK, 73104, USA.
- Vascular Cognitive Impairment and Neurodegeneration Program, Department of Translational Medicine, Semmelweis University, Budapest, Hungary.
- Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences, Center 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA.
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Zhang W, Davis CM, Zeppenfeld DM, Golgotiu K, Wang MX, Haveliwala M, Hong D, Li Y, Wang RK, Iliff JJ, Alkayed NJ. Role of endothelium-pericyte signaling in capillary blood flow response to neuronal activity. J Cereb Blood Flow Metab 2021; 41:1873-1885. [PMID: 33853406 PMCID: PMC8327110 DOI: 10.1177/0271678x211007957] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Local blood flow in the brain is tightly coupled to metabolic demands, a phenomenon termed functional hyperemia. Both capillaries and arterioles contribute to the hyperemic response to neuronal activity via different mechanisms and timescales. The nature and specific signaling involved in the hyperemic response of capillaries versus arterioles, and their temporal relationship are not fully defined. We determined the time-dependent changes in capillary flux and diameter versus arteriolar velocity and flow following whisker stimulation using optical microangiography (OMAG) and two-photon microscopy. We further characterized depth-resolved responses of individual capillaries versus capillary networks. We hypothesized that capillaries respond first to neuronal activation, and that they exhibit a coordinated response mediated via endothelial-derived epoxyeicosatrienoates (EETs) acting on pericytes. To visualize peri-capillary pericytes, we used Tie2-GFP/NG2-DsRed mice, and to determine the role of endothelial-derived EETs, we compared cerebrovascular responses to whisker stimulation between wild-type mice and mice with lower endothelial EETs (Tie2-hsEH). We found that capillaries respond immediately to neuronal activation in an orchestrated network-level manner, a response attenuated in Tie2-hsEH and inhibited by blocking EETs action on pericytes. These results demonstrate that capillaries are first responders during functional hyperemia, and that they exhibit a network-level response mediated via endothelial-derived EETs' action on peri-capillary pericytes.
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Affiliation(s)
- Wenri Zhang
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA
| | - Catherine M Davis
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA
| | - Douglas M Zeppenfeld
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA
| | - Kirsti Golgotiu
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA
| | - Marie X Wang
- Mental Illness Research, Education and Clinical Center, VA Puget Sound Health Care Center, Seattle, WA, USA.,Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, WA, USA
| | - Mariya Haveliwala
- Mental Illness Research, Education and Clinical Center, VA Puget Sound Health Care Center, Seattle, WA, USA.,Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, WA, USA
| | - Daniel Hong
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA
| | - Yuandong Li
- Department of Bioengineering, University of Washington School of Medicine, Seattle, WA, USA
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington School of Medicine, Seattle, WA, USA
| | - Jeffrey J Iliff
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA.,Mental Illness Research, Education and Clinical Center, VA Puget Sound Health Care Center, Seattle, WA, USA.,Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, WA, USA
| | - Nabil J Alkayed
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA.,Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA
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66
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István L, Czakó C, Élő Á, Mihály Z, Sótonyi P, Varga A, Ungvári Z, Csiszár A, Yabluchanskiy A, Conley S, Csipő T, Lipecz Á, Kovács I, Nagy ZZ. Imaging retinal microvascular manifestations of carotid artery disease in older adults: from diagnosis of ocular complications to understanding microvascular contributions to cognitive impairment. GeroScience 2021; 43:1703-1723. [PMID: 34100219 PMCID: PMC8492863 DOI: 10.1007/s11357-021-00392-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 05/24/2021] [Indexed: 02/06/2023] Open
Abstract
Carotid artery stenosis (CAS) is a consequence of systemic atherosclerotic disease affecting the aging populations of the Western world. CAS is frequently associated with cognitive impairment. However, the mechanisms contributing to the development of vascular cognitive impairment (VCI) associated with CAS are multifaceted and not fully understood. In addition to embolization and decreased blood flow due to the atherosclerotic lesion in the carotid artery, microcirculatory dysfunction in the cerebral circulation also plays a critical role in CAS-related VCI. To better understand the microvascular contributions to cognitive decline associated with CAS and evaluate microvascular protective effects of therapeutic interventions, it is essential to examine the structural and functional changes of the microvessels in the central nervous system (CNS). However, there are some limitations of in vivo brain vascular imaging modalities. The retinal microvasculature provides a unique opportunity to study pathogenesis of cerebral small vessel disease and VCI, because the cerebral circulation and the retinal circulation share similar anatomy, physiology and embryology. Similar microvascular pathologies may manifest in the brain and the retina, thus ocular examination can be used as a noninvasive screening tool to investigate pathological changes in the CNS associated with CAS. In this review, ocular signs of CAS and the retinal manifestations of CAS-associated microvascular dysfunction are discussed. The advantages and limitation of methods that are capable of imaging the ocular circulation (including funduscopy, fluorescein angiography, Doppler sonography, optical coherence tomography [OCT] and optical coherence tomography angiography [OCTA]) are discussed. The potential use of dynamic retinal vessel analysis (DVA), which allows for direct visualization of neurovascular coupling responses in the CNS, for understanding microvascular contributions to cognitive decline in CAS patients is also considered.
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Affiliation(s)
- Lilla István
- Department of Ophthalmology, Semmelweis University, 39 Mária Street, 1085, Budapest, Hungary
| | - Cecilia Czakó
- Department of Ophthalmology, Semmelweis University, 39 Mária Street, 1085, Budapest, Hungary
| | - Ágnes Élő
- Department of Ophthalmology, Semmelweis University, 39 Mária Street, 1085, Budapest, Hungary
| | - Zsuzsanna Mihály
- Department of Vascular & Endovascular Surgery, Semmelweis University, Budapest, Hungary
| | - Péter Sótonyi
- Department of Vascular & Endovascular Surgery, Semmelweis University, Budapest, Hungary
| | - Andrea Varga
- Department of Vascular & Endovascular Surgery, Semmelweis University, Budapest, Hungary
| | - Zoltán Ungvári
- Department of Biochemistry and Molecular Biology, Vascular Cognitive Impairment and Neurodegeneration Program, Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary
- Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- International Training Program in Geroscience, Theoretical Medicine Doctoral School/Departments of Medical Physics and Informatics & Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary
| | - Anna Csiszár
- Department of Biochemistry and Molecular Biology, Vascular Cognitive Impairment and Neurodegeneration Program, Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- International Training Program in Geroscience, Theoretical Medicine Doctoral School/Departments of Medical Physics and Informatics & Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Translational Medicine, Semmelweis University, Budapest, Hungary
| | - Andriy Yabluchanskiy
- Department of Biochemistry and Molecular Biology, Vascular Cognitive Impairment and Neurodegeneration Program, Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary
- Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Shannon Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Tamás Csipő
- Department of Biochemistry and Molecular Biology, Vascular Cognitive Impairment and Neurodegeneration Program, Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary
| | - Ágnes Lipecz
- Department of Ophthalmology, Semmelweis University, 39 Mária Street, 1085, Budapest, Hungary
- Department of Biochemistry and Molecular Biology, Vascular Cognitive Impairment and Neurodegeneration Program, Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary
- Department of Ophthalmology, Josa Andras Hospital, Nyiregyhaza, Hungary
| | - Illés Kovács
- Department of Ophthalmology, Semmelweis University, 39 Mária Street, 1085, Budapest, Hungary.
- Department of Ophthalmology, Weill Cornell Medical College, New York City, NY, USA.
- Department of Clinical Ophtalmology, Faculty of Health Sciences, Semmelweis University, Budapest, Hungary.
| | - Zoltán Zsolt Nagy
- Department of Ophthalmology, Semmelweis University, 39 Mária Street, 1085, Budapest, Hungary
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67
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Yang F, Li J, Song Y, Zhao M, Niemeyer JE, Luo P, Li D, Lin W, Ma H, Schwartz TH. Mesoscopic Mapping of Ictal Neurovascular Coupling in Awake Behaving Mice Using Optical Spectroscopy and Genetically Encoded Calcium Indicators. Front Neurosci 2021; 15:704834. [PMID: 34366781 PMCID: PMC8343016 DOI: 10.3389/fnins.2021.704834] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 06/30/2021] [Indexed: 11/13/2022] Open
Abstract
Unambiguously identifying an epileptic focus with high spatial resolution is a challenge, especially when no anatomic abnormality can be detected. Neurovascular coupling (NVC)-based brain mapping techniques are often applied in the clinic despite a poor understanding of ictal NVC mechanisms, derived primarily from recordings in anesthetized animals with limited spatial sampling of the ictal core. In this study, we used simultaneous wide-field mesoscopic imaging of GCamp6f and intrinsic optical signals (IOS) to record the neuronal and hemodynamic changes during acute ictal events in awake, behaving mice. Similar signals in isoflurane-anesthetized mice were compared to highlight the unique characteristics of the awake condition. In awake animals, seizures were more focal at the onset but more likely to propagate to the contralateral hemisphere. The HbT signal, derived from an increase in cerebral blood volume (CBV), was more intense in awake mice. As a result, the “epileptic dip” in hemoglobin oxygenation became inconsistent and unreliable as a mapping signal. Our data indicate that CBV-based imaging techniques should be more accurate than blood oxygen level dependent (BOLD)-based imaging techniques for seizure mapping in awake behaving animals.
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Affiliation(s)
- Fan Yang
- Department of Neurology, The First Hospital of Jilin University, Changchun, China.,Department of Neurological Surgery, Brain and Mind Research Institute, New York Presbyterian Hospital, Weill Cornell Medicine of Cornell University, New York, NY, United States
| | - Jing Li
- Department of Neurology, The First Hospital of Jilin University, Changchun, China.,Department of Neurological Surgery, Brain and Mind Research Institute, New York Presbyterian Hospital, Weill Cornell Medicine of Cornell University, New York, NY, United States
| | - Yan Song
- School of Nursing, Beihua University, Jilin City, China
| | - Mingrui Zhao
- Department of Neurological Surgery, Brain and Mind Research Institute, New York Presbyterian Hospital, Weill Cornell Medicine of Cornell University, New York, NY, United States
| | - James E Niemeyer
- Department of Neurological Surgery, Brain and Mind Research Institute, New York Presbyterian Hospital, Weill Cornell Medicine of Cornell University, New York, NY, United States
| | - Peijuan Luo
- Department of Neurology, The First Hospital of Jilin University, Changchun, China.,Department of Neurological Surgery, Brain and Mind Research Institute, New York Presbyterian Hospital, Weill Cornell Medicine of Cornell University, New York, NY, United States
| | - Dan Li
- Department of Radiology, The First Hospital of Jilin University, Changchun, China
| | - Weihong Lin
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Hongtao Ma
- Department of Neurological Surgery, Brain and Mind Research Institute, New York Presbyterian Hospital, Weill Cornell Medicine of Cornell University, New York, NY, United States
| | - Theodore H Schwartz
- Department of Neurological Surgery, Brain and Mind Research Institute, New York Presbyterian Hospital, Weill Cornell Medicine of Cornell University, New York, NY, United States
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68
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Rungta RL, Zuend M, Aydin AK, Martineau É, Boido D, Weber B, Charpak S. Diversity of neurovascular coupling dynamics along vascular arbors in layer II/III somatosensory cortex. Commun Biol 2021; 4:855. [PMID: 34244604 PMCID: PMC8270975 DOI: 10.1038/s42003-021-02382-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 06/10/2021] [Indexed: 11/08/2022] Open
Abstract
The spatial-temporal sequence of cerebral blood flow (CBF), cerebral blood volume (CBV) and blood velocity changes triggered by neuronal activation is critical for understanding functional brain imaging. This sequence follows a stereotypic pattern of changes across different zones of the vasculature in the olfactory bulb, the first relay of olfaction. However, in the cerebral cortex, where most human brain mapping studies are performed, the timing of activity evoked vascular events remains controversial. Here we utilized a single whisker stimulation model to map out functional hyperemia along vascular arbours from layer II/III to the surface of primary somatosensory cortex, in anesthetized and awake Thy1-GCaMP6 mice. We demonstrate that sensory stimulation triggers an increase in blood velocity within the mid-capillary bed and a dilation of upstream large capillaries, and the penetrating and pial arterioles. We report that under physiological stimulation, response onset times are highly variable across compartments of different vascular arbours. Furthermore, generating transfer functions (TFs) between neuronal Ca2+ and vascular dynamics across different brain states demonstrates that anesthesia decelerates neurovascular coupling (NVC). This spatial-temporal pattern of vascular events demonstrates functional diversity not only between different brain regions but also at the level of different vascular arbours within supragranular layers of the cerebral cortex.
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Affiliation(s)
- Ravi L Rungta
- INSERM U1128, Laboratory of Neurophysiology and New Microscopy, Université Paris Descartes, Paris, France.
- Faculté de Médecine Dentaire, Université de Montréal, Montréal, QC, Canada.
- Centre Interdisciplinaire de Recherche sur le Cerveau et l'Apprentissage, Université de Montréal, Montréal, QC, Canada.
- Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, QC, Canada.
| | - Marc Zuend
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Ali-Kemal Aydin
- INSERM U1128, Laboratory of Neurophysiology and New Microscopy, Université Paris Descartes, Paris, France
- INSERM, CNRS, Institut de la Vision, Sorbonne Université, Paris, France
| | - Éric Martineau
- Faculté de Médecine Dentaire, Université de Montréal, Montréal, QC, Canada
- Centre Interdisciplinaire de Recherche sur le Cerveau et l'Apprentissage, Université de Montréal, Montréal, QC, Canada
- Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, QC, Canada
| | - Davide Boido
- INSERM U1128, Laboratory of Neurophysiology and New Microscopy, Université Paris Descartes, Paris, France
- NeuroSpin, Bat. 145, Commissariat à l'Energie Atomique ' Saclay Center, Gif-sur-Yvette, France
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Serge Charpak
- INSERM U1128, Laboratory of Neurophysiology and New Microscopy, Université Paris Descartes, Paris, France.
- INSERM, CNRS, Institut de la Vision, Sorbonne Université, Paris, France.
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Yabluchanskiy A, Nyul-Toth A, Csiszar A, Gulej R, Saunders D, Towner R, Turner M, Zhao Y, Abdelkari D, Rypma B, Tarantini S. Age-related alterations in the cerebrovasculature affect neurovascular coupling and BOLD fMRI responses: Insights from animal models of aging. Psychophysiology 2021; 58:e13718. [PMID: 33141436 PMCID: PMC9166153 DOI: 10.1111/psyp.13718] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 08/10/2020] [Accepted: 09/28/2020] [Indexed: 12/11/2022]
Abstract
The present and future research efforts in cognitive neuroscience and psychophysiology rely on the measurement, understanding, and interpretation of blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) to effectively investigate brain function. Aging and age-associated pathophysiological processes change the structural and functional integrity of the cerebrovasculature which can significantly alter how the BOLD signal is recorded and interpreted. In order to gain an improved understanding of the benefits, drawbacks, and methodological implications for BOLD fMRI in the context of cognitive neuroscience, it is crucial to understand the cellular and molecular mechanism of age-related vascular pathologies. This review discusses the multifaceted effects of aging and the contributions of age-related pathologies on structural and functional integrity of the cerebral microcirculation as they has been investigated in animal models of aging, including age-related alterations in neurovascular coupling responses, cellular and molecular mechanisms involved in microvascular damage, vascular rarefaction, blood-brain barrier disruption, senescence, humoral deficiencies as they relate to, and potentially introduce confounding factors in the interpretation of BOLD fMRI.
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Affiliation(s)
- Andriy Yabluchanskiy
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Adam Nyul-Toth
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA,Institute of Biophysics, Biological Research Centre, Szeged, Hungary
| | - Anna Csiszar
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Rafal Gulej
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, Oklahoma, OK, USA
| | - Debra Saunders
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, Oklahoma, OK, USA
| | - Rheal Towner
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, Oklahoma, OK, USA
| | - Monroe Turner
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, TX, USA
| | - Yuguang Zhao
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, TX, USA
| | - Dema Abdelkari
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, TX, USA
| | - Bart Rypma
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, TX, USA,Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Stefano Tarantini
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA,International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary,Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
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70
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Bracko O, Cruz Hernández JC, Park L, Nishimura N, Schaffer CB. Causes and consequences of baseline cerebral blood flow reductions in Alzheimer's disease. J Cereb Blood Flow Metab 2021; 41:1501-1516. [PMID: 33444096 PMCID: PMC8221770 DOI: 10.1177/0271678x20982383] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 10/27/2020] [Accepted: 11/16/2020] [Indexed: 12/23/2022]
Abstract
Reductions of baseline cerebral blood flow (CBF) of ∼10-20% are a common symptom of Alzheimer's disease (AD) that appear early in disease progression and correlate with the severity of cognitive impairment. These CBF deficits are replicated in mouse models of AD and recent work shows that increasing baseline CBF can rapidly improve the performance of AD mice on short term memory tasks. Despite the potential role these data suggest for CBF reductions in causing cognitive symptoms and contributing to brain pathology in AD, there remains a poor understanding of the molecular and cellular mechanisms causing them. This review compiles data on CBF reductions and on the correlation of AD-related CBF deficits with disease comorbidities (e.g. cardiovascular and genetic risk factors) and outcomes (e.g. cognitive performance and brain pathology) from studies in both patients and mouse models, and discusses several potential mechanisms proposed to contribute to CBF reductions, based primarily on work in AD mouse models. Future research aimed at improving our understanding of the importance of and interplay between different mechanisms for CBF reduction, as well as at determining the role these mechanisms play in AD patients could guide the development of future therapies that target CBF reductions in AD.
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Affiliation(s)
- Oliver Bracko
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA
| | - Jean C Cruz Hernández
- Center for Systems Biology and Wellman Center for Photomedicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Laibaik Park
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY, USA
| | - Nozomi Nishimura
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA
| | - Chris B Schaffer
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA
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71
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Zimmerman B, Rypma B, Gratton G, Fabiani M. Age-related changes in cerebrovascular health and their effects on neural function and cognition: A comprehensive review. Psychophysiology 2021; 58:e13796. [PMID: 33728712 PMCID: PMC8244108 DOI: 10.1111/psyp.13796] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 01/11/2021] [Accepted: 02/08/2021] [Indexed: 12/11/2022]
Abstract
The process of aging includes changes in cellular biology that affect local interactions between cells and their environments and eventually propagate to systemic levels. In the brain, where neurons critically depend on an efficient and dynamic supply of oxygen and glucose, age-related changes in the complex interaction between the brain parenchyma and the cerebrovasculature have effects on health and functioning that negatively impact cognition and play a role in pathology. Thus, cerebrovascular health is considered one of the main mechanisms by which a healthy lifestyle, such as habitual cardiorespiratory exercise and a healthful diet, could lead to improved cognitive outcomes with aging. This review aims at detailing how the physiology of the cerebral vascular system changes with age and how these changes lead to differential trajectories of cognitive maintenance or decline. This provides a framework for generating specific mechanistic hypotheses about the efficacy of proposed interventions and lifestyle covariates that contribute to enhanced cognitive well-being. Finally, we discuss the methodological implications of age-related changes in the cerebral vasculature for human cognitive neuroscience research and propose directions for future experiments aimed at investigating age-related changes in the relationship between physiology and cognitive mechanisms.
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Affiliation(s)
- Benjamin Zimmerman
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Bart Rypma
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX, USA
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Gabriele Gratton
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Department of Psychology, University of Illinois at Urbana-Champaign, Champaign, IL, USA
- Neuroscience Program, University of Illinois at Urbana-Champaign, Champaign, IL, USA
| | - Monica Fabiani
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Department of Psychology, University of Illinois at Urbana-Champaign, Champaign, IL, USA
- Neuroscience Program, University of Illinois at Urbana-Champaign, Champaign, IL, USA
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72
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Precapillary sphincters and pericytes at first-order capillaries as key regulators for brain capillary perfusion. Proc Natl Acad Sci U S A 2021; 118:2023749118. [PMID: 34155102 DOI: 10.1073/pnas.2023749118] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Rises in local neural activity trigger local increases of cerebral blood flow, which is essential to match local energy demands. However, the specific location of microvascular flow control is incompletely understood. Here, we used two-photon microscopy to observe brain microvasculature in vivo. Small spatial movement of a three-dimensional (3D) vasculature makes it challenging to precisely measure vessel diameter at a single x-y plane. To overcome this problem, we carried out four-dimensional (x-y-z-t) imaging of brain microvessels during exposure to vasoactive molecules in order to constrain the impact of brain movements on the recordings. We demonstrate that rises in synaptic activity, acetylcholine, nitric oxide, cyclic guanosine monophosphate, ATP-sensitive potassium channels, and endothelin-1 exert far greater effects on brain precapillary sphincters and first-order capillaries than on penetrating arterioles or downstream capillaries, but with similar kinetics. The high level of responsiveness at precapillary sphincters and first-order capillaries was matched by a higher level of α-smooth muscle actin in pericytes as compared to penetrating arterioles and downstream capillaries. Mathematical modeling based on 3D vasculature reconstruction showed that precapillary sphincters predominantly regulate capillary blood flow and pressure as compared to penetrating arterioles and downstream capillaries. Our results confirm a key role for precapillary sphincters and pericytes on first-order capillaries as sensors and effectors of endothelium- or brain-derived vascular signals.
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73
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Zhao Y, Liu P, Turner MP, Abdelkarim D, Lu H, Rypma B. The neural-vascular basis of age-related processing speed decline. Psychophysiology 2021; 58:e13845. [PMID: 34115388 DOI: 10.1111/psyp.13845] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 04/14/2021] [Accepted: 04/19/2021] [Indexed: 12/12/2022]
Abstract
Most studies examining neurocognitive aging are based on the blood-oxygen level-dependent signal obtained during functional magnetic resonance imaging (fMRI). The physiological basis of this signal is neural-vascular coupling, the process by which neurons signal cerebrovasculature to dilate in response to an increase in active neural metabolism due to stimulation. These fMRI studies of aging rely on the hemodynamic equivalence assumption that this process is not disrupted by physiologic deterioration associated with aging. Studies of neural-vascular coupling challenge this assumption and show that neural-vascular coupling is closely related to cognition. In this review, we put forward a theory of processing speed decline in aging and how it is related to age-related neural-vascular coupling changes based on the results of studies elucidating the relationships between cognition, cerebrovascular dynamics, and aging.
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Affiliation(s)
- Yuguang Zhao
- School of Behavioral and Brain Sciences, Center for Brain Health, University of Texas at Dallas, Richardson, TX, USA
| | - Peiying Liu
- School of Medicine, Department of Radiology, Johns Hopkins University, Baltimore, MD, USA
| | - Monroe P Turner
- School of Behavioral and Brain Sciences, Center for Brain Health, University of Texas at Dallas, Richardson, TX, USA
| | - Dema Abdelkarim
- School of Behavioral and Brain Sciences, Center for Brain Health, University of Texas at Dallas, Richardson, TX, USA
| | - Hanzhang Lu
- School of Medicine, Department of Radiology, Johns Hopkins University, Baltimore, MD, USA
| | - Bart Rypma
- School of Behavioral and Brain Sciences, Center for Brain Health, University of Texas at Dallas, Richardson, TX, USA
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74
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Shaw K, Bell L, Boyd K, Grijseels DM, Clarke D, Bonnar O, Crombag HS, Hall CN. Neurovascular coupling and oxygenation are decreased in hippocampus compared to neocortex because of microvascular differences. Nat Commun 2021; 12:3190. [PMID: 34045465 PMCID: PMC8160329 DOI: 10.1038/s41467-021-23508-y] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 04/26/2021] [Indexed: 02/04/2023] Open
Abstract
The hippocampus is essential for spatial and episodic memory but is damaged early in Alzheimer's disease and is very sensitive to hypoxia. Understanding how it regulates its oxygen supply is therefore key for designing interventions to preserve its function. However, studies of neurovascular function in the hippocampus in vivo have been limited by its relative inaccessibility. Here we compared hippocampal and visual cortical neurovascular function in awake mice, using two photon imaging of individual neurons and vessels and measures of regional blood flow and haemoglobin oxygenation. We show that blood flow, blood oxygenation and neurovascular coupling were decreased in the hippocampus compared to neocortex, because of differences in both the vascular network and pericyte and endothelial cell function. Modelling oxygen diffusion indicates that these features of the hippocampal vasculature may restrict oxygen availability and could explain its sensitivity to damage during neurological conditions, including Alzheimer's disease, where the brain's energy supply is decreased.
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Affiliation(s)
- K Shaw
- School of Psychology and Sussex Neuroscience, University of Sussex, Falmer, Brighton, United Kingdom
| | - L Bell
- School of Psychology and Sussex Neuroscience, University of Sussex, Falmer, Brighton, United Kingdom
| | - K Boyd
- School of Psychology and Sussex Neuroscience, University of Sussex, Falmer, Brighton, United Kingdom
| | - D M Grijseels
- School of Psychology and Sussex Neuroscience, University of Sussex, Falmer, Brighton, United Kingdom
| | - D Clarke
- School of Psychology and Sussex Neuroscience, University of Sussex, Falmer, Brighton, United Kingdom
| | - O Bonnar
- School of Psychology and Sussex Neuroscience, University of Sussex, Falmer, Brighton, United Kingdom
| | - H S Crombag
- School of Psychology and Sussex Neuroscience, University of Sussex, Falmer, Brighton, United Kingdom
| | - C N Hall
- School of Psychology and Sussex Neuroscience, University of Sussex, Falmer, Brighton, United Kingdom.
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75
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Chico TJA, Kugler EC. Cerebrovascular development: mechanisms and experimental approaches. Cell Mol Life Sci 2021; 78:4377-4398. [PMID: 33688979 PMCID: PMC8164590 DOI: 10.1007/s00018-021-03790-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 02/04/2021] [Accepted: 02/12/2021] [Indexed: 12/13/2022]
Abstract
The cerebral vasculature plays a central role in human health and disease and possesses several unique anatomic, functional and molecular characteristics. Despite their importance, the mechanisms that determine cerebrovascular development are less well studied than other vascular territories. This is in part due to limitations of existing models and techniques for visualisation and manipulation of the cerebral vasculature. In this review we summarise the experimental approaches used to study the cerebral vessels and the mechanisms that contribute to their development.
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Affiliation(s)
- Timothy J A Chico
- Department of Infection, Immunity and Cardiovascular Disease, Medical School, University of Sheffield, Beech Hill Road, Sheffield, S10 2RX, UK.
- The Bateson Centre, Firth Court, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK.
- Insigneo Institute for in Silico Medicine, The Pam Liversidge Building, Sheffield, S1 3JD, UK.
| | - Elisabeth C Kugler
- Department of Infection, Immunity and Cardiovascular Disease, Medical School, University of Sheffield, Beech Hill Road, Sheffield, S10 2RX, UK.
- The Bateson Centre, Firth Court, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK.
- Insigneo Institute for in Silico Medicine, The Pam Liversidge Building, Sheffield, S1 3JD, UK.
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mTOR Attenuation with Rapamycin Reverses Neurovascular Uncoupling and Memory Deficits in Mice Modeling Alzheimer's Disease. J Neurosci 2021; 41:4305-4320. [PMID: 33888602 DOI: 10.1523/jneurosci.2144-20.2021] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 02/19/2021] [Accepted: 03/02/2021] [Indexed: 02/07/2023] Open
Abstract
Vascular dysfunction is a universal feature of aging and decreased cerebral blood flow has been identified as an early event in the pathogenesis of Alzheimer's disease (AD). Cerebrovascular dysfunction in AD includes deficits in neurovascular coupling (NVC), a mechanism that ensures rapid delivery of energy substrates to active neurons through the blood supply. The mechanisms underlying NVC impairment in AD, however, are not well understood. We have previously shown that mechanistic/mammalian target of rapamycin (mTOR) drives cerebrovascular dysfunction in models of AD by reducing the activity of endothelial nitric oxide synthase (eNOS), and that attenuation of mTOR activity with rapamycin is sufficient to restore eNOS-dependent cerebrovascular function. Here we show mTOR drives NVC impairments in an AD model through the inhibition of neuronal NOS (nNOS)- and non-NOS-dependent components of NVC, and that mTOR attenuation with rapamycin is sufficient to restore NVC and even enhance it above WT responses. Restoration of NVC and concomitant reduction of cortical amyloid-β levels effectively treated memory deficits in 12-month-old hAPP(J20) mice. These data indicate that mTOR is a critical driver of NVC dysfunction and underlies cognitive impairment in an AD model. Together with our previous findings, the present studies suggest that mTOR promotes cerebrovascular dysfunction in AD, which is associated with early disruption of nNOS activation, through its broad negative impact on nNOS as well as on non-NOS components of NVC. Our studies highlight the potential of mTOR attenuation as an efficacious treatment for AD and potentially other neurologic diseases of aging.SIGNIFICANCE STATEMENT Failure of the blood flow response to neuronal activation [neurovascular coupling (NVC)] in a model of AD precedes the onset of AD-like cognitive symptoms and is driven, to a large extent, by mammalian/mechanistic target of rapamycin (mTOR)-dependent inhibition of nitric oxide synthase activity. Our studies show that mTOR also drives AD-like failure of non-nitric oxide (NO)-mediated components of NVC. Thus, mTOR attenuation may serve to treat AD, where we find that neuronal NO synthase is profoundly reduced early in disease progression, and potentially other neurologic diseases of aging with cerebrovascular dysfunction as part of their etiology.
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Negri S, Faris P, Soda T, Moccia F. Endothelial signaling at the core of neurovascular coupling: The emerging role of endothelial inward-rectifier K + (K ir2.1) channels and N-methyl-d-aspartate receptors in the regulation of cerebral blood flow. Int J Biochem Cell Biol 2021; 135:105983. [PMID: 33894355 DOI: 10.1016/j.biocel.2021.105983] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 04/08/2021] [Accepted: 04/19/2021] [Indexed: 12/21/2022]
Abstract
Neurovascular coupling (NVC) represents the mechanisms whereby an increase in neuronal activity (NA) may lead to local vasodilation and increase in regional cerebral blood flow (CBF). It has long been thought that neurons and astrocytes generate the vasoactive mediators regulating local changes in CBF, whereas cerebrovascular endothelial cells are not able to directly sense NA. Unexpectedly, recent evidence demonstrated that brain microvascular endothelial cells may sense NA through inward-rectifier K+ (Kir2.1) channels and may detect synaptic activity via N-methyl-d-aspartate (NMDA) receptors (NMDARs). In the present perspective, therefore, we discuss the hypothesis that endothelial Kir2.1 channels and NMDARs play a key role in NVC and in CBF regulation, which is crucial to unravel the cellular and molecular underpinnings of blood oxygen level-dependent signals.
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Affiliation(s)
- Sharon Negri
- Department of Biology and Biotechnology "Lazzaro Spallanzani", Laboratory of General Physiology, University of Pavia, Pavia, Italy
| | - Pawan Faris
- Department of Biology and Biotechnology "Lazzaro Spallanzani", Laboratory of General Physiology, University of Pavia, Pavia, Italy
| | - Teresa Soda
- Department of Brain and Behavioral Sciences, University if Pavia, Pavia, Italy
| | - Francesco Moccia
- Department of Biology and Biotechnology "Lazzaro Spallanzani", Laboratory of General Physiology, University of Pavia, Pavia, Italy.
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Neumaier F, Kotliar K, Haeren RHL, Temel Y, Lüke JN, Seyam O, Lindauer U, Clusmann H, Hescheler J, Schubert GA, Schneider T, Albanna W. Retinal Vessel Responses to Flicker Stimulation Are Impaired in Ca v 2.3-Deficient Mice-An in-vivo Evaluation Using Retinal Vessel Analysis (RVA). Front Neurol 2021; 12:659890. [PMID: 33927686 PMCID: PMC8076560 DOI: 10.3389/fneur.2021.659890] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 03/17/2021] [Indexed: 12/30/2022] Open
Abstract
Objective: Metabolic demand increases with neuronal activity and adequate energy supply is ensured by neurovascular coupling (NVC). Impairments of NVC have been reported in the context of several diseases and may correlate with disease severity and outcome. Voltage-gated Ca2+-channels (VGCCs) are involved in the regulation of vasomotor tone. In the present study, we compared arterial and venous responses to flicker stimulation in Cav2.3-competent (Cav2.3[+/+]) and -deficient (Cav2.3[-/-]) mice using retinal vessel analysis. Methods: The mice were anesthetized and the pupil of one eye was dilated by application of a mydriaticum. An adapted prototype of retinal vessel analyzer was used to perform dynamic retinal vessel analysis. Arterial and venous responses were quantified in terms of the area under the curve (AUCart/AUCven) during flicker application, mean maximum dilation (mMDart/mMDven) and time to maximum dilation (tMDart/tMDven) during the flicker, dilation at flicker cessation (DFCart/DFCven), mean maximum constriction (mMCart/mMCven), time to maximum constriction (tMCart/tMCven) after the flicker and reactive magnitude (RMart/RMven). Results: A total of 33 retinal scans were conducted in 22 Cav2.3[+/+] and 11 Cav2.3[-/-] mice. Cav2.3[-/-] mice were characterized by attenuated and partially reversed arterial and venous responses, as reflected in significantly lower AUCart (p = 0.031) and AUCven (p = 0.047), a trend toward reduced DFCart (p = 0.100), DFCven (p = 0.100), mMDven (p = 0.075), and RMart (p = 0.090) and a trend toward increased tMDart (p = 0.096). Conclusion: To our knowledge, this is the first study using a novel, non-invasive analysis technique to document impairment of retinal vessel responses in VGCC-deficient mice. We propose that Cav2.3 channels could be involved in NVC and may contribute to the impairment of vasomotor responses under pathophysiological conditions.
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Affiliation(s)
- Felix Neumaier
- Department of Neurosurgery, RWTH Aachen University, Aachen, Germany
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Jülich, Germany
- Institute of Radiochemistry and Experimental Molecular Imaging, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Konstantin Kotliar
- Department of Medical Engineering and Technomathematics, FH Aachen University of Applied Sciences, Aachen, Germany
| | | | - Yasin Temel
- Department of Neurosurgery, Maastricht University Medical Center, Maastricht, Netherlands
| | - Jan Niklas Lüke
- Institute for Neurophysiology, University of Cologne, Cologne, Germany
| | - Osama Seyam
- Department of Medical Engineering and Technomathematics, FH Aachen University of Applied Sciences, Aachen, Germany
| | - Ute Lindauer
- Department of Neurosurgery, RWTH Aachen University, Aachen, Germany
- Tranlational Neurosurgery and Neurobiology, RWTH Aachen University, Aachen, Germany
| | - Hans Clusmann
- Department of Neurosurgery, RWTH Aachen University, Aachen, Germany
| | - Jürgen Hescheler
- Institute for Neurophysiology, University of Cologne, Cologne, Germany
| | | | - Toni Schneider
- Institute for Neurophysiology, University of Cologne, Cologne, Germany
| | - Walid Albanna
- Department of Neurosurgery, RWTH Aachen University, Aachen, Germany
- Institute for Neurophysiology, University of Cologne, Cologne, Germany
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79
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Tarantini S, Balasubramanian P, Yabluchanskiy A, Ashpole NM, Logan S, Kiss T, Ungvari A, Nyúl-Tóth Á, Schwartzman ML, Benyo Z, Sonntag WE, Csiszar A, Ungvari Z. IGF1R signaling regulates astrocyte-mediated neurovascular coupling in mice: implications for brain aging. GeroScience 2021; 43:901-911. [PMID: 33674953 PMCID: PMC8110646 DOI: 10.1007/s11357-021-00350-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 03/01/2021] [Indexed: 12/13/2022] Open
Abstract
Aging is associated with a significant deficiency in circulating insulin-like growth factor-1 (IGF-1), which has an important role in the pathogenesis of age-related vascular cognitive impairment (VCI). Impairment of moment-to-moment adjustment of regional cerebral blood flow via neurovascular coupling (NVC) importantly contributes to VCI. Previous studies established a causal link between circulating IGF-1 deficiency and neurovascular dysfunction. Release of vasodilator mediators from activated astrocytes plays a key role in NVC. To determine the impact of impaired IGF-1 signaling on astrocytic function, astrocyte-mediated NVC responses were studied in a novel mouse model of astrocyte-specific knockout of IGF1R (GFAP-CreERT2/Igf1rf/f) and accelerated neurovascular aging. We found that mice with disrupted astrocytic IGF1R signaling exhibit impaired NVC responses, decreased stimulated release of the vasodilator gliotransmitter epoxy-eicosatrienoic acids (EETs), and upregulation of soluble epoxy hydrolase (sEH), which metabolizes and inactivates EETs. Collectively, our findings provide additional evidence that IGF-1 promotes astrocyte health and maintains normal NVC, protecting cognitive health.
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Affiliation(s)
- Stefano Tarantini
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Reynolds Oklahoma Center on Aging, Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA.
- International Training Program in Geroscience, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.
- Peggy and Charles Stephenson Cancer Center, Oklahoma City, OK, 73104, USA.
- Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary.
| | - Priya Balasubramanian
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Reynolds Oklahoma Center on Aging, Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA
| | - Andriy Yabluchanskiy
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Reynolds Oklahoma Center on Aging, Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA
- International Training Program in Geroscience, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
- Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Nicole M Ashpole
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Reynolds Oklahoma Center on Aging, Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA
- Pharmacology Division, Department of BioMolecular Sciences, University of Mississippi School of Pharmacy, Oxford, MS, USA
| | - Sreemathi Logan
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Reynolds Oklahoma Center on Aging, Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA
- Department of Rehabilitation Sciences, College of Allied Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73117, USA
| | - Tamas Kiss
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Reynolds Oklahoma Center on Aging, Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA
- International Training Program in Geroscience, Theoretical Medicine Doctoral School/Departments of Medical Physics and Informatics & Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary
| | - Anna Ungvari
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Reynolds Oklahoma Center on Aging, Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA
| | - Ádám Nyúl-Tóth
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Reynolds Oklahoma Center on Aging, Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA
- International Training Program in Geroscience, Institute of Biophysics, Biological Research Centre, Eötvös Loránd Research Network (ELKH), Szeged, Hungary
- Vascular Cognitive Impairment and Neurodegeneration Program/HCEMM, Department of Translational Medicine, Semmelweis University, Budapest, Hungary
| | - Michal L Schwartzman
- Department of Pharmacology, New York Medical College School of Medicine, Valhalla, NY, USA
| | - Zoltan Benyo
- Vascular Cognitive Impairment and Neurodegeneration Program/HCEMM, Department of Translational Medicine, Semmelweis University, Budapest, Hungary
| | - William E Sonntag
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Reynolds Oklahoma Center on Aging, Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA
| | - Anna Csiszar
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Reynolds Oklahoma Center on Aging, Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA
- International Training Program in Geroscience, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
- Peggy and Charles Stephenson Cancer Center, Oklahoma City, OK, 73104, USA
- International Training Program in Geroscience, Theoretical Medicine Doctoral School/Departments of Medical Physics and Informatics & Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary
- Vascular Cognitive Impairment and Neurodegeneration Program/HCEMM, Department of Translational Medicine, Semmelweis University, Budapest, Hungary
| | - Zoltan Ungvari
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Reynolds Oklahoma Center on Aging, Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA
- International Training Program in Geroscience, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
- Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary
- International Training Program in Geroscience, Theoretical Medicine Doctoral School/Departments of Medical Physics and Informatics & Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary
- Vascular Cognitive Impairment and Neurodegeneration Program/HCEMM, Department of Translational Medicine, Semmelweis University, Budapest, Hungary
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Thakore P, Alvarado MG, Ali S, Mughal A, Pires PW, Yamasaki E, Pritchard HA, Isakson BE, Tran CHT, Earley S. Brain endothelial cell TRPA1 channels initiate neurovascular coupling. eLife 2021; 10:63040. [PMID: 33635784 PMCID: PMC7935492 DOI: 10.7554/elife.63040] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 02/25/2021] [Indexed: 02/07/2023] Open
Abstract
Cerebral blood flow is dynamically regulated by neurovascular coupling to meet the dynamic metabolic demands of the brain. We hypothesized that TRPA1 channels in capillary endothelial cells are stimulated by neuronal activity and instigate a propagating retrograde signal that dilates upstream parenchymal arterioles to initiate functional hyperemia. We find that activation of TRPA1 in capillary beds and post-arteriole transitional segments with mural cell coverage initiates retrograde signals that dilate upstream arterioles. These signals exhibit a unique mode of biphasic propagation. Slow, short-range intercellular Ca2+ signals in the capillary network are converted to rapid electrical signals in transitional segments that propagate to and dilate upstream arterioles. We further demonstrate that TRPA1 is necessary for functional hyperemia and neurovascular coupling within the somatosensory cortex of mice in vivo. These data establish endothelial cell TRPA1 channels as neuronal activity sensors that initiate microvascular vasodilatory responses to redirect blood to regions of metabolic demand.
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Affiliation(s)
- Pratish Thakore
- Department of Pharmacology, Center for Molecular and Cellular Signaling in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, United States
| | - Michael G Alvarado
- Department of Pharmacology, Center for Molecular and Cellular Signaling in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, United States
| | - Sher Ali
- Department of Pharmacology, Center for Molecular and Cellular Signaling in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, United States
| | - Amreen Mughal
- Department of Pharmacology, College of Medicine, University of Vermont, Burlington, United States
| | - Paulo W Pires
- Department of Physiology, College of Medicine, University of Arizona, Tucson, United States
| | - Evan Yamasaki
- Department of Pharmacology, Center for Molecular and Cellular Signaling in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, United States
| | - Harry At Pritchard
- Department of Pharmacology, Center for Molecular and Cellular Signaling in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, United States.,Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom
| | - Brant E Isakson
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, United States.,Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, United States
| | - Cam Ha T Tran
- Department of Physiology & Cell Biology, Center for Molecular and Cellular Signaling in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, United States
| | - Scott Earley
- Department of Pharmacology, Center for Molecular and Cellular Signaling in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, United States
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81
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Mughal A, Harraz OF, Gonzales AL, Hill-Eubanks D, Nelson MT. PIP 2 Improves Cerebral Blood Flow in a Mouse Model of Alzheimer's Disease. FUNCTION (OXFORD, ENGLAND) 2021; 2:zqab010. [PMID: 33763649 PMCID: PMC7955025 DOI: 10.1093/function/zqab010] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 02/16/2021] [Accepted: 02/16/2021] [Indexed: 02/05/2023]
Abstract
Alzheimer's disease (AD) is a leading cause of dementia and a substantial healthcare burden. Despite this, few treatment options are available for controlling AD symptoms. Notably, neuronal activity-dependent increases in cortical cerebral blood flow (CBF; functional hyperemia) are attenuated in AD patients, but the associated pathological mechanisms are not fully understood at the molecular level. A fundamental mechanism underlying functional hyperemia is activation of capillary endothelial inward-rectifying K+ (Kir2.1) channels by neuronally derived potassium (K+), which evokes a retrograde capillary-to-arteriole electrical signal that dilates upstream arterioles, increasing blood delivery to downstream active regions. Here, using a mouse model of familial AD (5xFAD), we tested whether this impairment in functional hyperemia is attributable to reduced activity of capillary Kir2.1 channels. In vivo CBF measurements revealed significant reductions in whisker stimulation (WS)-induced and K+-induced hyperemic responses in 5xFAD mice compared with age-matched controls. Notably, measurements of whole-cell currents in freshly isolated 5xFAD capillary endothelial cells showed that Kir2.1 current density was profoundly reduced, suggesting a defect in Kir2.1 function. Because Kir2.1 activity absolutely depends on binding of phosphatidylinositol 4,5-bisphosphate (PIP2) to the channel, we hypothesized that capillary Kir2.1 channel impairment could be corrected by exogenously supplying PIP2. As predicted, a PIP2 analog restored Kir2.1 current density to control levels. More importantly, systemic administration of PIP2 restored K+-induced CBF increases and WS-induced functional hyperemic responses in 5xFAD mice. Collectively, these data provide evidence that PIP2-mediated restoration of capillary endothelial Kir2.1 function improves neurovascular coupling and CBF in the setting of AD.
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Affiliation(s)
- Amreen Mughal
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, VT, USA
| | - Osama F Harraz
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, VT, USA,Vermont Center for Cardiovascular and Brain Health, University of Vermont, Burlington, VT, USA
| | - Albert L Gonzales
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, VT, USA,Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, NV, USA
| | - David Hill-Eubanks
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, VT, USA
| | - Mark T Nelson
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, VT, USA,Vermont Center for Cardiovascular and Brain Health, University of Vermont, Burlington, VT, USA,Division of Cardiovascular Sciences, University of Manchester, Manchester, UK,Address correspondence to M.T.N. (e-mail: )
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82
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Moretti R, Giuffré M, Caruso P, Gazzin S, Tiribelli C. Homocysteine in Neurology: A Possible Contributing Factor to Small Vessel Disease. Int J Mol Sci 2021; 22:ijms22042051. [PMID: 33669577 PMCID: PMC7922986 DOI: 10.3390/ijms22042051] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 02/14/2021] [Accepted: 02/15/2021] [Indexed: 12/19/2022] Open
Abstract
Homocysteine (Hcy) is a sulfur-containing amino acid generated during methionine metabolism, accumulation of which may be caused by genetic defects or the deficit of vitamin B12 and folate. A serum level greater than 15 micro-mols/L is defined as hyperhomocysteinemia (HHcy). Hcy has many roles, the most important being the active participation in the transmethylation reactions, fundamental for the brain. Many studies focused on the role of homocysteine accumulation in vascular or degenerative neurological diseases, but the results are still undefined. More is known in cardiovascular disease. HHcy is a determinant for the development and progression of inflammation, atherosclerotic plaque formation, endothelium, arteriolar damage, smooth muscle cell proliferation, and altered-oxidative stress response. Conversely, few studies focused on the relationship between HHcy and small vessel disease (SVD), despite the evidence that mice with HHcy showed a significant end-feet disruption of astrocytes with a diffuse SVD. A severe reduction of vascular aquaporin-4-water channels, lower levels of high-functioning potassium channels, and higher metalloproteinases are also observed. HHcy modulates the N-homocysteinylation process, promoting a pro-coagulative state and damage of the cellular protein integrity. This altered process could be directly involved in the altered endothelium activation, typical of SVD and protein quality, inhibiting the ubiquitin-proteasome system control. HHcy also promotes a constant enhancement of microglia activation, inducing the sustained pro-inflammatory status observed in SVD. This review article addresses the possible role of HHcy in small-vessel disease and understands its pathogenic impact.
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Affiliation(s)
- Rita Moretti
- Department of Medical, Surgical and Health Sciences, University of Trieste, 34149 Trieste, Italy; (M.G.); (P.C.)
- Correspondence:
| | - Mauro Giuffré
- Department of Medical, Surgical and Health Sciences, University of Trieste, 34149 Trieste, Italy; (M.G.); (P.C.)
| | - Paola Caruso
- Department of Medical, Surgical and Health Sciences, University of Trieste, 34149 Trieste, Italy; (M.G.); (P.C.)
| | - Silvia Gazzin
- Italian Liver Foundation, AREA SCIENCE PARK, 34149 Trieste, Italy; (S.G.); (C.T.)
| | - Claudio Tiribelli
- Italian Liver Foundation, AREA SCIENCE PARK, 34149 Trieste, Italy; (S.G.); (C.T.)
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83
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Balasubramanian P, Kiss T, Tarantini S, Nyúl-Tóth Á, Ahire C, Yabluchanskiy A, Csipo T, Lipecz A, Tabak A, Institoris A, Csiszar A, Ungvari Z. Obesity-induced cognitive impairment in older adults: a microvascular perspective. Am J Physiol Heart Circ Physiol 2021; 320:H740-H761. [PMID: 33337961 PMCID: PMC8091942 DOI: 10.1152/ajpheart.00736.2020] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Over two-thirds of individuals aged 65 and older are obese or overweight in the United States. Epidemiological data show an association between the degree of adiposity and cognitive dysfunction in the elderly. In this review, the pathophysiological roles of microvascular mechanisms, including impaired endothelial function and neurovascular coupling responses, microvascular rarefaction, and blood-brain barrier disruption in the genesis of cognitive impairment in geriatric obesity are considered. The potential contribution of adipose-derived factors and fundamental cellular and molecular mechanisms of senescence to exacerbated obesity-induced cerebromicrovascular impairment and cognitive decline in aging are discussed.
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Affiliation(s)
- Priya Balasubramanian
- 1Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Tamas Kiss
- 1Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma,2International Training Program in Geroscience, Theoretical Medicine Doctoral School, Departments of Medical Physics and Informatics & Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary
| | - Stefano Tarantini
- 1Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma,3International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine, Department of Public Health, Semmelweis University, Budapest, Hungary,4Department of Health Promotion Sciences, the Hudson College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Ádám Nyúl-Tóth
- 1Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma,5International Training Program in Geroscience, Institute of Biophysics, Biological Research Centre, Szeged, Hungary
| | - Chetan Ahire
- 1Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Andriy Yabluchanskiy
- 1Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Tamas Csipo
- 1Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma,3International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine, Department of Public Health, Semmelweis University, Budapest, Hungary,6International Training Program in Geroscience, Division of Clinical Physiology, Department of Cardiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Agnes Lipecz
- 1Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma,3International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine, Department of Public Health, Semmelweis University, Budapest, Hungary
| | - Adam Tabak
- 3International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine, Department of Public Health, Semmelweis University, Budapest, Hungary,7Department of Internal Medicine and Oncology, Faculty of Medicine, Semmelweis University, Budapest, Hungary,8Department of Epidemiology and Public Health, University College London, London, United Kingdom
| | - Adam Institoris
- 9Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Anna Csiszar
- 1Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma,2International Training Program in Geroscience, Theoretical Medicine Doctoral School, Departments of Medical Physics and Informatics & Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary
| | - Zoltan Ungvari
- 1Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma,2International Training Program in Geroscience, Theoretical Medicine Doctoral School, Departments of Medical Physics and Informatics & Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary,3International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine, Department of Public Health, Semmelweis University, Budapest, Hungary,4Department of Health Promotion Sciences, the Hudson College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
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84
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Trigiani LJ, Lecrux C, Royea J, Lavoie JL, Lesage F, Pilote L, Hamel E. A Longitudinal Pilot Study on Cognition and Cerebral Hemodynamics in a Mouse Model of Preeclampsia Superimposed on Hypertension: Looking at Mothers and Their Offspring. Front Physiol 2021; 12:611984. [PMID: 33584345 PMCID: PMC7878560 DOI: 10.3389/fphys.2021.611984] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 01/06/2021] [Indexed: 12/20/2022] Open
Abstract
Preeclampsia is a common hypertensive disorder in pregnant women and whose causes and consequences have focused primarily on cardiovascular outcomes on the mother and offspring, often without taking into consideration the possible effects on the brain. One possible cause of preeclampsia has been attributed to alterations in the renin-angiotensin system, which has also been linked to cognitive decline. In this pilot study, we use a transgenic mouse model that chronically overexpresses human angiotensinogen and renin (R+A+ mice) that displayed characteristics of preeclampsia such as proteinuria during gestation. Offspring of these mothers as well as from control mothers were also examined. We were primarily interested in detecting whether cognitive deficits were present in the mothers and offspring in the long term and used a spatial learning and memory task as well as an object recognition task at three timepoints: 3, 8, and 12 months post-partum or post-natal, while measuring blood pressure and performing urine analysis after each timepoint. While we did not find significant deficits in preeclamptic mothers at the later timepoints, we did observe negative consequences in the pups of R+A+ mice that coincided with hemodynamic alterations whereby pups had higher whisker-evoked oxygenated hemoglobin levels and increased cerebral blood flow responses compared to control pups. Our study provides validation of this preeclampsia mouse model for future studies to decipher the underlying mechanisms of long-term cognitive deficits found in offspring.
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Affiliation(s)
- Lianne J Trigiani
- Laboratory of Cerebrovascular Research, Montreal Neurological Institute, McGill University, Montréal, QC, Canada
| | - Clotilde Lecrux
- Laboratory of Cerebrovascular Research, Montreal Neurological Institute, McGill University, Montréal, QC, Canada
| | - Jessika Royea
- Laboratory of Cerebrovascular Research, Montreal Neurological Institute, McGill University, Montréal, QC, Canada
| | - Julie L Lavoie
- Centre de Recherche du Centre Hospitalier de l'Universite de Montreal and School of Kinesiology and physical activity sciences, Université de Montréal, Montréal, QC, Canada
| | - Frédéric Lesage
- Biomedical Engineering Institute, École Polytechnique de Montréal, Montréal, QC, Canada
| | - Louise Pilote
- Department of Medicine, Centre for Outcomes Research and Evaluation, McGill University Health Centre, Montréal, QC, Canada
| | - Edith Hamel
- Laboratory of Cerebrovascular Research, Montreal Neurological Institute, McGill University, Montréal, QC, Canada
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85
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Segura-Collar B, Mata-Martínez P, Hernández-Laín A, Sánchez-Gómez P, Gargini R. Blood-Brain Barrier Disruption: A Common Driver of Central Nervous System Diseases. Neuroscientist 2021; 28:222-237. [PMID: 33446074 DOI: 10.1177/1073858420985838] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The brain is endowed with a unique cellular composition and organization, embedded within a vascular network and isolated from the circulating blood by a specialized frontier, the so-called blood-brain barrier (BBB), which is necessary for its proper function. Recent reports have shown that increments in the permeability of the blood vessels facilitates the entry of toxic components and immune cells to the brain parenchyma and alters the phenotype of the supporting astrocytes. All of these might contribute to the progression of different pathologies such as brain cancers or neurodegenerative diseases. Although it is well known that BBB breakdown occurs due to pericyte malfunctioning or to the lack of stability of the blood vessels, its participation in the diverse neural diseases needs further elucidation. This review summarizes what it is known about BBB structure and function and how its instability might trigger or promote neuronal degeneration and glioma progression, with a special focus on the role of pericytes as key modulators of the vasculature. Moreover, we will discuss some recent reports that highlights the participation of the BBB alterations in glioma growth. This pan-disease analysis might shed some light into these otherwise untreatable diseases and help to design better therapeutic approaches.
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Affiliation(s)
| | | | | | | | - Ricardo Gargini
- Neurooncology Unit, Instituto de Salud Carlos III-UFIEC, Madrid, Spain
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86
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Poplawsky AJ, Iordanova B, Vazquez AL, Kim SG, Fukuda M. Postsynaptic activity of inhibitory neurons evokes hemodynamic fMRI responses. Neuroimage 2021; 225:117457. [PMID: 33069862 PMCID: PMC7818351 DOI: 10.1016/j.neuroimage.2020.117457] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 09/15/2020] [Accepted: 10/12/2020] [Indexed: 02/08/2023] Open
Abstract
Functional MRI responses are localized to the synaptic sites of evoked inhibitory neurons, but it is unknown whether, or by what mechanisms, these neurons initiate functional hyperemia. Here, the neuronal origins of these hemodynamic responses were investigated by fMRI or local field potential and blood flow measurements during topical application of pharmacological agents when GABAergic granule cells in the rat olfactory bulb were synaptically targeted. First, to examine if postsynaptic activation of these inhibitory neurons was required for neurovascular coupling, we applied an NMDA receptor antagonist during cerebral blood volume-weighted fMRI acquisition and found that responses below the drug application site (up to ~1.5 mm) significantly decreased within ~30 min. Similarly, large decreases in granule cell postsynaptic activities and blood flow responses were observed when AMPA or NMDA receptor antagonists were applied. Second, inhibition of nitric oxide synthase preferentially decreased the initial, fast component of the blood flow response, while inhibitors of astrocyte-specific glutamate transporters and vasoactive intestinal peptide receptors did not decrease blood flow responses. Third, inhibition of GABA release with a presynaptic GABAB receptor agonist caused less reduction of neuronal and blood flow responses compared to the postsynaptic glutamate receptor antagonists. In conclusion, local hyperemia by synaptically-evoked inhibitory neurons was primarily driven by their postsynaptic activities, possibly through NMDA receptor-dependent calcium signaling that was not wholly dependent on nitric oxide.
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Affiliation(s)
| | - Bistra Iordanova
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15203, United States
| | - Alberto L Vazquez
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA 15203, United States; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15203, United States
| | - Seong-Gi Kim
- Center for Neuroscience Imaging Research, Institute for Basic Science, Suwon 440-330, Korea; Department of Biomedical Engineering, Sungkyunkwan University, Suwon, 440-330, Korea
| | - Mitsuhiro Fukuda
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA 15203, United States.
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87
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Tsvetanov KA, Henson RNA, Rowe JB. Separating vascular and neuronal effects of age on fMRI BOLD signals. Philos Trans R Soc Lond B Biol Sci 2021; 376:20190631. [PMID: 33190597 PMCID: PMC7741031 DOI: 10.1098/rstb.2019.0631] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/19/2020] [Indexed: 12/14/2022] Open
Abstract
Accurate identification of brain function is necessary to understand the neurobiology of cognitive ageing, and thereby promote well-being across the lifespan. A common tool used to investigate neurocognitive ageing is functional magnetic resonance imaging (fMRI). However, although fMRI data are often interpreted in terms of neuronal activity, the blood oxygenation level-dependent (BOLD) signal measured by fMRI includes contributions of both vascular and neuronal factors, which change differentially with age. While some studies investigate vascular ageing factors, the results of these studies are not well known within the field of neurocognitive ageing and therefore vascular confounds in neurocognitive fMRI studies are common. Despite over 10 000 BOLD-fMRI papers on ageing, fewer than 20 have applied techniques to correct for vascular effects. However, neurovascular ageing is not only a confound in fMRI, but an important feature in its own right, to be assessed alongside measures of neuronal ageing. We review current approaches to dissociate neuronal and vascular components of BOLD-fMRI of regional activity and functional connectivity. We highlight emerging evidence that vascular mechanisms in the brain do not simply control blood flow to support the metabolic needs of neurons, but form complex neurovascular interactions that influence neuronal function in health and disease. This article is part of the theme issue 'Key relationships between non-invasive functional neuroimaging and the underlying neuronal activity'.
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Affiliation(s)
- Kamen A. Tsvetanov
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0SZ, UK
- Department of Psychology, University of Cambridge, Cambridge CB2 3EB, UK
| | - Richard N. A. Henson
- Department of Psychiatry, University of Cambridge, Cambridge CB2 0SP, UK
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, Cambridge CB2 7EF, UK
| | - James B. Rowe
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0SZ, UK
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, Cambridge CB2 7EF, UK
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88
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Howarth C, Mishra A, Hall CN. More than just summed neuronal activity: how multiple cell types shape the BOLD response. Philos Trans R Soc Lond B Biol Sci 2021; 376:20190630. [PMID: 33190598 PMCID: PMC7116385 DOI: 10.1098/rstb.2019.0630] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/22/2020] [Indexed: 12/11/2022] Open
Abstract
Functional neuroimaging techniques are widely applied to investigations of human cognition and disease. The most commonly used among these is blood oxygen level-dependent (BOLD) functional magnetic resonance imaging. The BOLD signal occurs because neural activity induces an increase in local blood supply to support the increased metabolism that occurs during activity. This supply usually outmatches demand, resulting in an increase in oxygenated blood in an active brain region, and a corresponding decrease in deoxygenated blood, which generates the BOLD signal. Hence, the BOLD response is shaped by an integration of local oxygen use, through metabolism, and supply, in the blood. To understand what information is carried in BOLD signals, we must understand how several cell types in the brain-local excitatory neurons, inhibitory neurons, astrocytes and vascular cells (pericytes, vascular smooth muscle and endothelial cells), and their modulation by ascending projection neurons-contribute to both metabolism and haemodynamic changes. Here, we review the contributions of each cell type to the regulation of cerebral blood flow and metabolism, and discuss situations where a simplified interpretation of the BOLD response as reporting local excitatory activity may misrepresent important biological phenomena, for example with regards to arousal states, ageing and neurological disease. This article is part of the theme issue 'Key relationships between non-invasive functional neuroimaging and the underlying neuronal activity'.
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Affiliation(s)
- Clare Howarth
- Department of Psychology, University of Sheffield, Sheffield S1 2LT, UK
| | - Anusha Mishra
- Department of Neurology, Jungers Center for Neurosciences Research, and Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR 97239, USA
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89
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Li M, Liu Q, Guo R, Yang S, Jiang P, Chen X, Wu J, Cao Y, Wang S. Perinidal Angiogenesis Is a Predictor for Neurovascular Uncoupling in the Periphery of Brain Arteriovenous Malformations: A Task-Based and Resting-State fMRI Study. J Magn Reson Imaging 2020; 54:186-196. [PMID: 33345355 DOI: 10.1002/jmri.27469] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/25/2020] [Accepted: 11/25/2020] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Potential neurovascular uncoupling (NVU) related to perinidal angiogenesis (PA) of brain arteriovenous malformations (AVMs) may cause inappropriate presurgical mapping using functional magnetic resonance imaging (fMRI), resulting in overconfident resection and postoperative morbidity. PURPOSE To evaluate the potential impact of PA upon fMRI blood oxygen level-dependent signal in the periphery of AVMs. STUDY TYPE Prospective. POPULATION Twenty-one patients with AVMs located in the primary sensorimotor cortex (SM1) undergoing task-based fMRI (hand motor), and 19 patients with supratentorial AVMs undergoing resting-state fMRI. FIELD STRENGTH/SEQUENCE 3.0T, echo-planar, time-of-flight, and magnetization-prepared rapid gradient-echo. ASSESSMENT The presence of PA was determined by three observers (Y.C., J.W., and X.C.) according to digital subtraction angiography and MR angiography. Interhemispheric asymmetry of fMRI activations contralateral to hand movements was evaluated with the interhemispheric ratio of the average t-value within ipsilesional SM1 to contralesional SM1. Regional homogeneity (ReHo) and fractional amplitude of low-frequency fluctuations (fALFF) were extracted from ring-shaped perinidal regions and contralateral homologous regions, and the corresponding interhemispheric ratios were calculated. The effect of PA on the interhemispheric asymmetry of motor activations, ReHo, and fALFF was estimated. STATISTICAL TESTS Pearson analysis, paired and independent t-test, multiple linear regression, Friedman test, and factorial analysis of variance were used. RESULTS Motor activations were significantly reduced in ipsilesional SM1 compared to contralesional SM1 (P < 0.05). The presence of PA was the independent predictor of activation loss in ipsilateral SM1(P < 0.05). Furthermore, perinidal regions exhibited reduced ReHo compared to the homologous regions (P < 0.05). PA was significantly associated with the decline of ReHo and fALFF in perinidal regions (P < 0.05, for both). DATA CONCLUSION The presence of PA can predict perinidal NVU that may confound the interpretation of both task-based and resting-state fMRI, highlighting the importance of alternative approaches of brain functional localization in improving treatment of AVMs. LEVEL OF EVIDENCE 2 TECHNICAL EFFICACY STAGE: 2.
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Affiliation(s)
- Maogui Li
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,China National Clinical Research Center for Neurological Diseases, Beijing, China.,Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, China
| | - Qingyuan Liu
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,China National Clinical Research Center for Neurological Diseases, Beijing, China.,Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, China
| | - Rui Guo
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,China National Clinical Research Center for Neurological Diseases, Beijing, China.,Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, China
| | - Shuzhe Yang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,China National Clinical Research Center for Neurological Diseases, Beijing, China.,Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, China
| | - Pengjun Jiang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,China National Clinical Research Center for Neurological Diseases, Beijing, China.,Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, China
| | - Xin Chen
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,China National Clinical Research Center for Neurological Diseases, Beijing, China.,Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, China
| | - Jun Wu
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,China National Clinical Research Center for Neurological Diseases, Beijing, China.,Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, China
| | - Yong Cao
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,China National Clinical Research Center for Neurological Diseases, Beijing, China.,Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, China
| | - Shuo Wang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,China National Clinical Research Center for Neurological Diseases, Beijing, China.,Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, China
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90
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Ross JM, Kim C, Allen D, Crouch EE, Narsinh K, Cooke DL, Abla AA, Nowakowski TJ, Winkler EA. The Expanding Cell Diversity of the Brain Vasculature. Front Physiol 2020; 11:600767. [PMID: 33343397 PMCID: PMC7744630 DOI: 10.3389/fphys.2020.600767] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/10/2020] [Indexed: 12/12/2022] Open
Abstract
The cerebrovasculature is essential to brain health and is tasked with ensuring adequate delivery of oxygen and metabolic precursors to ensure normal neurologic function. This is coordinated through a dynamic, multi-directional cellular interplay between vascular, neuronal, and glial cells. Molecular exchanges across the blood-brain barrier or the close matching of regional blood flow with brain activation are not uniformly assigned to arteries, capillaries, and veins. Evidence has supported functional segmentation of the brain vasculature. This is achieved in part through morphologic or transcriptional heterogeneity of brain vascular cells-including endothelium, pericytes, and vascular smooth muscle. Advances with single cell genomic technologies have shown increasing cell complexity of the brain vasculature identifying previously unknown cell types and further subclassifying transcriptional diversity in cardinal vascular cell types. Cell-type specific molecular transitions or zonations have been identified. In this review, we summarize emerging evidence for the expanding vascular cell diversity in the brain and how this may provide a cellular basis for functional segmentation along the arterial-venous axis.
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Affiliation(s)
- Jayden M. Ross
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA, United States
- Department of Anatomy, University of California, San Francisco, San Francisco, CA, United States
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA, United States
- The Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, United States
| | - Chang Kim
- Department of Anatomy, University of California, San Francisco, San Francisco, CA, United States
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA, United States
- The Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, United States
| | - Denise Allen
- Department of Anatomy, University of California, San Francisco, San Francisco, CA, United States
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA, United States
- The Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, United States
| | - Elizabeth E. Crouch
- Department of Pediatrics, University of California, San Francisco, San Francisco, CA, United States
| | - Kazim Narsinh
- Department of Radiology, University of California, San Francisco, San Francisco, CA, United States
| | - Daniel L. Cooke
- Department of Radiology, University of California, San Francisco, San Francisco, CA, United States
| | - Adib A. Abla
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA, United States
| | - Tomasz J. Nowakowski
- Department of Anatomy, University of California, San Francisco, San Francisco, CA, United States
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA, United States
- The Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, United States
- Department of Radiology, University of California, San Francisco, San Francisco, CA, United States
| | - Ethan A. Winkler
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA, United States
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91
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Chin-Hao Chen R, Atry F, Richner T, Brodnick S, Pisaniello J, Ness J, Suminski AJ, Williams J, Pashaie R. A system identification analysis of optogenetically evoked electrocorticography and cerebral blood flow responses. J Neural Eng 2020; 17:056049. [PMID: 32299067 DOI: 10.1088/1741-2552/ab89fc] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE The main objective of this research was to study the coupling between neural circuits and the vascular network in the cortex of small rodents from system engineering point of view and generate a mathematical model for the dynamics of neurovascular coupling. The model was adopted to implement closed-loop blood flow control algorithms. APPROACH We used a combination of advanced technologies including optogenetics, electrocorticography, and optical coherence tomography to stimulate selected populations of neurons and simultaneously record induced electrocorticography and hemodynamic signals. We adopted system identification methods to analyze the acquired data and investigate the relation between optogenetic neural activation and consequential electrophysiology and blood flow responses. MAIN RESULTS We showed that the developed model, once trained by the acquired data, could successfully regenerate subtle spatio-temporal features of evoked electrocorticography and cerebral blood flow responses following an onset of optogenetic stimulation. SIGNIFICANCE The long term goal of this research is to open a new line for computational analysis of neurovascular coupling particularly in pathologies where the normal process of blood flow regulation in the central nervous system is disrupted including Alzheimer's disease.
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Affiliation(s)
- Rex Chin-Hao Chen
- Electrical Engineering, Computer Science Department, University of Wisconsin-Milwaukee, 3200N Cramer St., Milwaukee, WI, United States of America
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92
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Anfray A, Drieu A, Hingot V, Hommet Y, Yetim M, Rubio M, Deffieux T, Tanter M, Orset C, Vivien D. Circulating tPA contributes to neurovascular coupling by a mechanism involving the endothelial NMDA receptors. J Cereb Blood Flow Metab 2020; 40:2038-2054. [PMID: 31665952 PMCID: PMC7786842 DOI: 10.1177/0271678x19883599] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The increase of cerebral blood flow evoked by neuronal activity is essential to ensure enough energy supply to the brain. In the neurovascular unit, endothelial cells are ideally placed to regulate key neurovascular functions of the brain. Nevertheless, some outstanding questions remain about their exact role neurovascular coupling (NVC). Here, we postulated that the tissue-type plasminogen activator (tPA) present in the circulation might contribute to NVC by a mechanism dependent of its interaction with endothelial N-Methyl-D-Aspartate Receptor (NMDAR). To address this question, we used pharmacological and genetic approaches to interfere with vascular tPA-dependent NMDAR signaling, combined with laser speckle flowmetry, intravital microscopy and ultrafast functional ultrasound in vivo imaging. We found that the tPA present in the blood circulation is capable of potentiating the cerebral blood flow increase induced by the activation of the mouse somatosensorial cortex, and that this effect is mediated by a tPA-dependent activation of NMDAR expressed at the luminal part of endothelial cells of arteries. Although blood molecules, such as acetylcholine, bradykinin or ATP are known to regulate vascular tone and induce vessel dilation, our present data provide the first evidence that circulating tPA is capable of influencing neurovascular coupling (NVC).
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Affiliation(s)
- Antoine Anfray
- Normandie University, UNICAEN, INSERM, UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), GIP Cyceron, Caen, France
| | - Antoine Drieu
- Normandie University, UNICAEN, INSERM, UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), GIP Cyceron, Caen, France
| | - Vincent Hingot
- Institut Langevin, CNRS, INSERM, ESPCI Paris, PSL Research University, Paris, France
| | - Yannick Hommet
- Normandie University, UNICAEN, INSERM, UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), GIP Cyceron, Caen, France
| | - Mervé Yetim
- Normandie University, UNICAEN, INSERM, UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), GIP Cyceron, Caen, France
| | - Marina Rubio
- Normandie University, UNICAEN, INSERM, UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), GIP Cyceron, Caen, France
| | - Thomas Deffieux
- Institut Langevin, CNRS, INSERM, ESPCI Paris, PSL Research University, Paris, France
| | - Mickael Tanter
- Institut Langevin, CNRS, INSERM, ESPCI Paris, PSL Research University, Paris, France
| | - Cyrille Orset
- Normandie University, UNICAEN, INSERM, UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), GIP Cyceron, Caen, France
| | - Denis Vivien
- Normandie University, UNICAEN, INSERM, UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), GIP Cyceron, Caen, France
- CHU Caen, Department of Clinical Research, Caen Normandie University Hospital, Avenue de la Côte de Nacre, Caen, France
- Denis Vivien, INSERM UMR-S U1237 “Physiopathology and Imaging of Neurological Disorders”, University Caen Normandie, GIP Cyceron, Bd Becquerel, BP5229, Caen 14074, France.
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93
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Presa JL, Saravia F, Bagi Z, Filosa JA. Vasculo-Neuronal Coupling and Neurovascular Coupling at the Neurovascular Unit: Impact of Hypertension. Front Physiol 2020; 11:584135. [PMID: 33101063 PMCID: PMC7546852 DOI: 10.3389/fphys.2020.584135] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 09/04/2020] [Indexed: 12/18/2022] Open
Abstract
Components of the neurovascular unit (NVU) establish dynamic crosstalk that regulates cerebral blood flow and maintain brain homeostasis. Here, we describe accumulating evidence for cellular elements of the NVU contributing to critical physiological processes such as cerebral autoregulation, neurovascular coupling, and vasculo-neuronal coupling. We discuss how alterations in the cellular mechanisms governing NVU homeostasis can lead to pathological changes in which vascular endothelial and smooth muscle cell, pericyte and astrocyte function may play a key role. Because hypertension is a modifiable risk factor for stroke and accelerated cognitive decline in aging, we focus on hypertension-associated changes on cerebral arteriole function and structure, and the molecular mechanisms through which these may contribute to cognitive decline. We gather recent emerging evidence concerning cognitive loss in hypertension and the link with vascular dementia and Alzheimer’s disease. Collectively, we summarize how vascular dysfunction, chronic hypoperfusion, oxidative stress, and inflammatory processes can uncouple communication at the NVU impairing cerebral perfusion and contributing to neurodegeneration.
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Affiliation(s)
- Jessica L Presa
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, GA, United States.,Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina
| | - Flavia Saravia
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina
| | - Zsolt Bagi
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Jessica A Filosa
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, GA, United States
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94
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Tau induces PSD95-neuronal NOS uncoupling and neurovascular dysfunction independent of neurodegeneration. Nat Neurosci 2020; 23:1079-1089. [PMID: 32778793 PMCID: PMC7896353 DOI: 10.1038/s41593-020-0686-7] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 07/02/2020] [Indexed: 02/06/2023]
Abstract
Cerebrovascular abnormalities have emerged as a preclinical manifestation of Alzheimer’s disease and frontotemporal dementia, diseases characterized by accumulation of hyperphosphorylated forms of the microtubule associated protein tau. However, it is unclear if tau contributes to these neurovascular alterations independent of neurodegeneration. We report that mice expressing mutated tau exhibit a selective suppression of neural activity-induced cerebral blood flow increases that precedes tau pathology and cognitive impairment. The dysfunction is attributable to reduced vasodilatation of intracerebral arterioles and is reversible by turning down tau production. Mechanistically, the failure of neurovascular coupling involves tau-induced dissociation of neuronal nitric oxide synthase from post synaptic-density-95 and reduced production of the potent vasodilator nitric oxide during glutamatergic synaptic activity. The data identify glutamatergic signaling dysfunction and nitric oxide deficiency as yet-undescribed early manifestations of tau pathobiology independent of neurodegeneration, and provide a mechanism for the neurovascular alterations observed in the preclinical stages of tauopathies.
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95
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Abstract
Sleep maintains the function of the entire body through homeostasis. Chronic sleep deprivation (CSD) is a prime health concern in the modern world. Previous reports have shown that CSD has profound negative effects on brain vasculature at both the cellular and molecular levels, and that this is a major cause of cognitive dysfunction and early vascular ageing. However, correlations among sleep deprivation (SD), brain vascular changes and ageing have barely been looked into. This review attempts to correlate the alterations in the levels of major neurotransmitters (acetylcholine, adrenaline, GABA and glutamate) and signalling molecules (Sirt1, PGC1α, FOXO, P66shc, PARP1) in SD and changes in brain vasculature, cognitive dysfunction and early ageing. It also aims to connect SD-induced loss in the number of dendritic spines and their effects on alterations in synaptic plasticity, cognitive disabilities and early vascular ageing based on data available in scientific literature. To the best of our knowledge, this is the first article providing a pathophysiological basis to link SD to brain vascular ageing.
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96
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Industry compensation and self-reported financial conflicts of interest among authors of highly cited peripheral artery disease studies. J Vasc Surg 2020; 72:673-684. [DOI: 10.1016/j.jvs.2019.09.053] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 09/07/2019] [Indexed: 12/20/2022]
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97
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Abstract
Blood flow in the retina increases in response to light-evoked neuronal activity, ensuring that retinal neurons receive an adequate supply of oxygen and nutrients as metabolic demands vary. This response, termed "functional hyperemia," is disrupted in diabetic retinopathy. The reduction in functional hyperemia may result in retinal hypoxia and contribute to the development of retinopathy. This review will discuss the neurovascular coupling signaling mechanisms that generate the functional hyperemia response in the retina, the changes to neurovascular coupling that occur in diabetic retinopathy, possible treatments for restoring functional hyperemia and retinal oxygen levels, and changes to functional hyperemia that occur in the diabetic brain.
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98
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Vascular contributions to 16p11.2 deletion autism syndrome modeled in mice. Nat Neurosci 2020; 23:1090-1101. [PMID: 32661394 DOI: 10.1038/s41593-020-0663-1] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 06/01/2020] [Indexed: 02/08/2023]
Abstract
While the neuronal underpinnings of autism spectrum disorder (ASD) are being unraveled, vascular contributions to ASD remain elusive. Here, we investigated postnatal cerebrovascular development in the 16p11.2df/+ mouse model of 16p11.2 deletion ASD syndrome. We discover that 16p11.2 hemizygosity leads to male-specific, endothelium-dependent structural and functional neurovascular abnormalities. In 16p11.2df/+ mice, endothelial dysfunction results in impaired cerebral angiogenesis at postnatal day 14, and in altered neurovascular coupling and cerebrovascular reactivity at postnatal day 50. Moreover, we show that there is defective angiogenesis in primary 16p11.2df/+ mouse brain endothelial cells and in induced-pluripotent-stem-cell-derived endothelial cells from human carriers of the 16p11.2 deletion. Finally, we find that mice with an endothelium-specific 16p11.2 deletion (16p11.2ΔEC) partially recapitulate some of the behavioral changes seen in 16p11.2 syndrome, specifically hyperactivity and impaired motor learning. By showing that developmental 16p11.2 haploinsufficiency from endothelial cells results in neurovascular and behavioral changes in adults, our results point to a potential role for endothelial impairment in ASD.
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99
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Neuronal regulation of the blood-brain barrier and neurovascular coupling. Nat Rev Neurosci 2020; 21:416-432. [PMID: 32636528 DOI: 10.1038/s41583-020-0322-2] [Citation(s) in RCA: 173] [Impact Index Per Article: 43.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/21/2020] [Indexed: 12/31/2022]
Abstract
To continuously process neural activity underlying sensation, movement and cognition, the CNS requires a homeostatic microenvironment that is not only enriched in nutrients to meet its high metabolic demands but that is also devoid of toxins that might harm the sensitive neural tissues. This highly regulated microenvironment is made possible by two unique features of CNS vasculature absent in the peripheral organs. First, the blood-blood barrier, which partitions the circulating blood from the CNS, acts as a gatekeeper to facilitate the selective trafficking of substances between the blood and the parenchyma. Second, neurovascular coupling ensures that, following local neural activation, regional blood flow is increased to quickly supply more nutrients and remove metabolic waste. Here, we review how neural and vascular activity act on one another with regard to these two properties.
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100
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Shin P, Yoon JH, Jeong Y, Oh WY. High-speed optical coherence tomography angiography for the measurement of stimulus-induced retrograde vasodilation of cerebral pial arteries in awake mice. NEUROPHOTONICS 2020; 7:030502. [PMID: 32923509 PMCID: PMC7481125 DOI: 10.1117/1.nph.7.3.030502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 08/18/2020] [Indexed: 06/01/2023]
Abstract
Significance: Having a clear understanding of functional hyperemia is crucial for functional brain imaging and neurological disease research. Vasodilation induced by sensory stimulus propagates from the arterioles to the upstream pial arteries in a retrograde fashion. As retrograde vasodilation occurs briefly in the early stage of functional hyperemia, an imaging technique with a high temporal resolution is required for its measurement. Aim: We aimed to present an imaging method to measure stimulus-induced retrograde vasodilation in awake animals. Approach: An imaging method based on optical coherence tomography angiography, which enables a high-speed and label-free vessel diameter measurement, was developed and applied for the investigation. Results: The propagation speed of retrograde vasodilation of pial artery was measured in awake mice. Other characteristics of functional hyperemia such as temporal profile and amplitude of the vascular response were also investigated. Conclusions: Our results provide detailed information of stimulus-induced hemodynamic response in the brain of awake mice and suggest the potential utility of our imaging method for the study of functional hyperemia in normal and diseased brain.
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Affiliation(s)
- Paul Shin
- Korea Advanced Institute of Science and Technology, Department of Mechanical Engineering, Daejeon, Republic of Korea
- Korea Advanced Institute of Science and Technology, KI for Health Science and Technology, Daejeon, Republic of Korea
| | - Jin-Hui Yoon
- Korea Advanced Institute of Science and Technology, KI for Health Science and Technology, Daejeon, Republic of Korea
- Korea Advanced Institute of Science and Technology, Department of Bio and Brain Engineering, Daejeon, Republic of Korea
| | - Yong Jeong
- Korea Advanced Institute of Science and Technology, KI for Health Science and Technology, Daejeon, Republic of Korea
- Korea Advanced Institute of Science and Technology, Department of Bio and Brain Engineering, Daejeon, Republic of Korea
| | - Wang-Yuhl Oh
- Korea Advanced Institute of Science and Technology, Department of Mechanical Engineering, Daejeon, Republic of Korea
- Korea Advanced Institute of Science and Technology, KI for Health Science and Technology, Daejeon, Republic of Korea
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