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Liu S, Liu F, Lin Z, Yin W, Fang S, Piao Y, Liu L, Shen Y. Identification of cortical arteries and veins in awake mice using two-photon microscopy. J Anat 2024. [PMID: 39034848 DOI: 10.1111/joa.14110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 06/03/2024] [Accepted: 06/28/2024] [Indexed: 07/23/2024] Open
Abstract
Distinguishing arteries from veins in the cerebral cortex is critical for studying hemodynamics under pathophysiological conditions, which plays an important role in the diagnosis and treatment of various vessel-related diseases. However, due to the complexity of the cerebral vascular network, it is challenging to identify arteries and veins in vivo. Here, we demonstrate an artery-vein separation method that employs a combination of multiple scanning modes of two-photon microscopy and a custom-designed stereoscopic fixation device for mice. In this process, we propose a novel method for determining the line scanning direction, which allows us to determine the blood flow directions. The vasculature branches have been identified using an optimized z-stack scanning mode, followed by the separation of blood vessel types according to the directions of blood flow and branching patterns. Using this strategy, the penetrating arterioles and penetrating venules in awake mice could be accurately identified and the type of cerebral thrombus has been also successfully isolated without any empirical knowledge or algorithms. Our research presents a new, more accurate, and efficient method for cortical artery-vein separation in awake mice, providing a useful strategy for the application of two-photon microscopy in the study of cerebrovascular pathophysiology.
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Affiliation(s)
- Shuangshuang Liu
- Core Facilities, Zhejiang University School of Medicine, Hangzhou, China
| | - FangYue Liu
- School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhaoxiaonan Lin
- Core Facilities, Zhejiang University School of Medicine, Hangzhou, China
| | - Wei Yin
- Core Facilities, Zhejiang University School of Medicine, Hangzhou, China
| | - Sanhua Fang
- Core Facilities, Zhejiang University School of Medicine, Hangzhou, China
| | - Ying Piao
- College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, China
| | - Li Liu
- Core Facilities, Zhejiang University School of Medicine, Hangzhou, China
| | - Yi Shen
- School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, China
- NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou, China
- National Health and Disease Human Brain Tissue Resource Center, Hangzhou, China
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Broggini T, Duckworth J, Ji X, Liu R, Xia X, Mächler P, Shaked I, Munting LP, Iyengar S, Kotlikoff M, van Veluw SJ, Vergassola M, Mishne G, Kleinfeld D. Long-wavelength traveling waves of vasomotion modulate the perfusion of cortex. Neuron 2024; 112:2349-2367.e8. [PMID: 38781972 PMCID: PMC11257831 DOI: 10.1016/j.neuron.2024.04.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 03/28/2024] [Accepted: 04/30/2024] [Indexed: 05/25/2024]
Abstract
Brain arterioles are active, multicellular complexes whose diameters oscillate at ∼ 0.1 Hz. We assess the physiological impact and spatiotemporal dynamics of vaso-oscillations in the awake mouse. First, vaso-oscillations in penetrating arterioles, which source blood from pial arterioles to the capillary bed, profoundly impact perfusion throughout neocortex. The modulation in flux during resting-state activity exceeds that of stimulus-induced activity. Second, the change in perfusion through arterioles relative to the change in their diameter is weak. This implies that the capillary bed dominates the hydrodynamic resistance of brain vasculature. Lastly, the phase of vaso-oscillations evolves slowly along arterioles, with a wavelength that exceeds the span of the cortical mantle and sufficient variability to establish functional cortical areas as parcels of uniform phase. The phase-gradient supports traveling waves in either direction along both pial and penetrating arterioles. This implies that waves along penetrating arterioles can mix, but not directionally transport, interstitial fluids.
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Affiliation(s)
- Thomas Broggini
- Department of Physics, University of California, San Diego, La Jolla, CA 92093, USA; Goethe University Frankfurt, Department of Neurosurgery, 60528 Frankfurt am Main, Germany; Frankfurt Cancer Institute, Goethe University Frankfurt, 60528 Frankfurt am Main, Germany
| | - Jacob Duckworth
- Department of Physics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Xiang Ji
- Department of Physics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Rui Liu
- Department of Physics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Xinyue Xia
- Halıcıoğlu Data Science Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Philipp Mächler
- Department of Physics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Iftach Shaked
- Department of Physics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Leon Paul Munting
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Satish Iyengar
- Department of Statistics, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Michael Kotlikoff
- College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Susanne J van Veluw
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
| | | | - Gal Mishne
- Halıcıoğlu Data Science Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - David Kleinfeld
- Department of Physics, University of California, San Diego, La Jolla, CA 92093, USA; Department of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA.
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Bagheri M, Habibzadeh S, Moeini M. Transient Changes in Cerebral Tissue Oxygen, Glucose, and Temperature by Microstrokes: A Computational Study. Microcirculation 2024:e12872. [PMID: 38944839 DOI: 10.1111/micc.12872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Revised: 05/09/2024] [Accepted: 06/08/2024] [Indexed: 07/02/2024]
Abstract
OBJECTIVE This study focuses on evaluating the disruptions in key physiological parameters during microstroke events to assess their severity. METHODS A mathematical model was developed to simulate the changes in cerebral tissue pO2, glucose concentration, and temperature due to blood flow interruptions. The model considers variations in baseline cerebral blood flow (CBF), capillary density, and blood oxygen/glucose levels, as well as ambient temperature changes. RESULTS Simulations indicate that complete blood flow obstruction still allows for limited glucose availability, supporting nonoxidative metabolism and potentially exacerbating lactate buildup and acidosis. Partial obstructions decrease tissue pO2, with minimal impact on glucose level, which can remain almost unchanged or even slightly increase. Reduced CBF, capillary density, or blood oxygen due to aging or disease enhances hypoxia risk at lower obstruction levels, with capillary density having a significant effect on stroke severity by influencing both pO2 and glucose levels. Conditions could lead to co-occurrence of hypoxia/hypoglycemia or hypoxia/hyperglycemia, each worsening outcomes. Temperature effects were minimal in deep brain regions but varied near the skull by 0.2-0.8°C depending on ambient temperature. CONCLUSIONS The model provides insights into the conditions driving severe stroke outcomes based on estimated levels of hypoxia, hypoglycemia, hyperglycemia, and temperature changes.
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Affiliation(s)
- Marzieh Bagheri
- Department of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
| | - Sajjad Habibzadeh
- Department of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
| | - Mohammad Moeini
- Department of Biomedical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
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Stefanski M, Arora Y, Cheung M, Dutta A. Modal Analysis of Cerebrovascular Effects for Digital Health Integration of Neurostimulation Therapies-A Review of Technology Concepts. Brain Sci 2024; 14:591. [PMID: 38928591 PMCID: PMC11201600 DOI: 10.3390/brainsci14060591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2024] [Revised: 05/31/2024] [Accepted: 06/04/2024] [Indexed: 06/28/2024] Open
Abstract
Transcranial electrical stimulation (tES) is increasingly recognized for its potential to modulate cerebral blood flow (CBF) and evoke cerebrovascular reactivity (CVR), which are crucial in conditions like mild cognitive impairment (MCI) and dementia. This study explores the impact of tES on the neurovascular unit (NVU), employing a physiological modeling approach to simulate the vascular response to electric fields generated by tES. Utilizing the FitzHugh-Nagumo model for neuroelectrical activity, we demonstrate how tES can initiate vascular responses such as vasoconstriction followed by delayed vasodilation in cerebral arterioles, potentially modulated by a combination of local metabolic demands and autonomic regulation (pivotal locus coeruleus). Here, four distinct pathways within the NVU were modeled to reflect the complex interplay between synaptic activity, astrocytic influences, perivascular potassium dynamics, and smooth muscle cell responses. Modal analysis revealed characteristic dynamics of these pathways, suggesting that oscillatory tES may finely tune the vascular tone by modulating the stiffness and elasticity of blood vessel walls, possibly by also impacting endothelial glycocalyx function. The findings underscore the therapeutic potential vis-à-vis blood-brain barrier safety of tES in modulating neurovascular coupling and cognitive function needing the precise modulation of NVU dynamics. This technology review supports the human-in-the-loop integration of tES leveraging digital health technologies for the personalized management of cerebral blood flow, offering new avenues for treating vascular cognitive disorders. Future studies should aim to optimize tES parameters using computational modeling and validate these models in clinical settings, enhancing the understanding of tES in neurovascular health.
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Affiliation(s)
- Marcel Stefanski
- School of Engineering, University of Lincoln, Lincoln LN6 7TS, UK
| | - Yashika Arora
- Department of Biomedical Engineering, University at Buffalo, Buffalo, NY 14228, USA
| | - Mancheung Cheung
- Department of Biomedical Engineering, University at Buffalo, Buffalo, NY 14228, USA
| | - Anirban Dutta
- School of Engineering, University of Lincoln, Lincoln LN6 7TS, UK
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Hunt RD, Cipolla MJ. Chronic hypertension alters the relationship between collateral blood flow, cortical cerebral blood flow, and brain tissue oxygenation. J Cereb Blood Flow Metab 2024:271678X241258569. [PMID: 38806143 DOI: 10.1177/0271678x241258569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
This study measured the relationship between pial collateral (leptomeningeal anastomoses, LMA) flow, intraparenchymal cortical cerebral blood flow (cCBF) and brain tissue oxygenation (btO2) during acute ischemic stroke to investigate how pial flow translates to downstream cCBF and btO2 and examined how this relationship is altered in hypertension. Proximal transient middle cerebral artery occlusion (tMCAO) was performed in male Wistar (n = 8/group) and Spontaneously Hypertensive Rats (SHR, n = 8/group). A combination laser Doppler-oxygen probe was placed within the expected cortical peri-infarct in addition to a surface laser doppler probe which measured LMA flow. Phenylephrine (PE) was infused 30 minutes into tMCAO to increase blood pressure (BP) by 30% for 10 minutes and assessed CBF autoregulation. During the initial 30-minute period of tMCAO, btO2 and cCBF were lower in SHR compared to Wistar rats (btO2: 11.5 ± 10.5 vs 17.5 ± 10.8 mmHg and cCBF: -29.7 ± 23.3% vs -17.8 ± 41.9%); however, LMA flow was similar between groups. The relationship between LMA flow, cCBF and btO2 were interdependent in Wistar rats. However, this relationship was disrupted in SHR rats and partially restored by induced hypertension. This study provides evidence that cCBF and btO2 were diminished during tMCAO in chronic hypertension, and that induced hypertension was beneficial regardless of hypertensive status.
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Affiliation(s)
- Ryan D Hunt
- Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - Marilyn J Cipolla
- Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA
- Department of Electrical and Biomedical Engineering, University of Vermont, College of Engineering and Mathematical Sciences, Burlington, VT, USA
- Department of Pharmacology, University of Vermont, Larner College of Medicine, Burlington, VT, USA
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA
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Dreier JP, Joerk A, Uchikawa H, Horst V, Lemale CL, Radbruch H, McBride DW, Vajkoczy P, Schneider UC, Xu R. All Three Supersystems-Nervous, Vascular, and Immune-Contribute to the Cortical Infarcts After Subarachnoid Hemorrhage. Transl Stroke Res 2024:10.1007/s12975-024-01242-z. [PMID: 38689162 DOI: 10.1007/s12975-024-01242-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 03/12/2024] [Accepted: 03/14/2024] [Indexed: 05/02/2024]
Abstract
The recently published DISCHARGE-1 trial supports the observations of earlier autopsy and neuroimaging studies that almost 70% of all focal brain damage after aneurysmal subarachnoid hemorrhage are anemic infarcts of the cortex, often also affecting the white matter immediately below. The infarcts are not limited by the usual vascular territories. About two-fifths of the ischemic damage occurs within ~ 48 h; the remaining three-fifths are delayed (within ~ 3 weeks). Using neuromonitoring technology in combination with longitudinal neuroimaging, the entire sequence of both early and delayed cortical infarct development after subarachnoid hemorrhage has recently been recorded in patients. Characteristically, cortical infarcts are caused by acute severe vasospastic events, so-called spreading ischemia, triggered by spontaneously occurring spreading depolarization. In locations where a spreading depolarization passes through, cerebral blood flow can drastically drop within a few seconds and remain suppressed for minutes or even hours, often followed by high-amplitude, sustained hyperemia. In spreading depolarization, neurons lead the event, and the other cells of the neurovascular unit (endothelium, vascular smooth muscle, pericytes, astrocytes, microglia, oligodendrocytes) follow. However, dysregulation in cells of all three supersystems-nervous, vascular, and immune-is very likely involved in the dysfunction of the neurovascular unit underlying spreading ischemia. It is assumed that subarachnoid blood, which lies directly on the cortex and enters the parenchyma via glymphatic channels, triggers these dysregulations. This review discusses the neuroglial, neurovascular, and neuroimmunological dysregulations in the context of spreading depolarization and spreading ischemia as critical elements in the pathogenesis of cortical infarcts after subarachnoid hemorrhage.
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Affiliation(s)
- Jens P Dreier
- Center for Stroke Research Berlin, Campus Charité Mitte, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117, Berlin, Germany.
- Department of Experimental Neurology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.
- Department of Neurology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.
- Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany.
- Einstein Center for Neurosciences Berlin, Berlin, Germany.
| | - Alexander Joerk
- Department of Neurology, Jena University Hospital, Jena, Germany
| | - Hiroki Uchikawa
- Barrow Aneurysm & AVM Research Center, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA
| | - Viktor Horst
- Center for Stroke Research Berlin, Campus Charité Mitte, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117, Berlin, Germany
- Institute of Neuropathology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Coline L Lemale
- Center for Stroke Research Berlin, Campus Charité Mitte, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117, Berlin, Germany
- Department of Experimental Neurology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Helena Radbruch
- Institute of Neuropathology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Devin W McBride
- The Vivian L. Smith Department of Neurosurgery, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Peter Vajkoczy
- Department of Neurosurgery, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Ulf C Schneider
- Department of Neurosurgery, Cantonal Hospital of Lucerne and University of Lucerne, Lucerne, Switzerland
| | - Ran Xu
- Department of Neurosurgery, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- DZHK, German Centre for Cardiovascular Research, Berlin, Germany
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Jamshidi M, Ventimiglia T, Sudres P, Zhang C, Lesage F, Rooney W, Schwartz D, Linninger AA. Impact of stalling events on microcirculatory hemodynamics in the aged brain. Microcirculation 2024; 31:e12845. [PMID: 38265175 PMCID: PMC11014774 DOI: 10.1111/micc.12845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 12/11/2023] [Accepted: 01/05/2024] [Indexed: 01/25/2024]
Abstract
OBJECTIVE The role of cerebral microvasculature in cognitive dysfunction can be investigated by identifying the impact of blood flow on cortical tissue oxygenation. In this paper, the impact of capillary stalls on microcirculatory characteristics such as flow and hematocrit (Ht) in the cortical angioarchitecture is studied. METHODS Using a deterministic mathematical model to simulate blood flow in a realistic mouse cortex, hemodynamics parameters, including pressure, flow, vessel diameter-adjustable hematocrit, and transit time are calculated as a function of stalling events. RESULTS Using a non-linear plasma skimming model, it is observed that Ht increases in the penetrating arteries from the pial vessels as a function of cortical depth. The incidence of stalling on Ht distribution along the blood network vessels shows reduction of RBCs around the tissue near occlusion sites and decreased Ht concentration downstream from the blockage points. Moreover, upstream of the occlusion, there is a noticeable increase of the Ht, leading to larger flow resistance due to higher blood viscosity. We predicted marked changes in transit time behavior due to stalls which match trends observed in mice in vivo. CONCLUSIONS These changes to blood cell quantity and quality may be implicated in the development of Alzheimer's disease and contribute to the course of the illness.
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Affiliation(s)
- Mohammad Jamshidi
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Thomas Ventimiglia
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Patrice Sudres
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Cong Zhang
- Department of Electrical Engineering, Polytechnique Montréal, Montreal, Canada
| | - Frederic Lesage
- Department of Electrical Engineering, Polytechnique Montréal, Montreal, Canada
| | - William Rooney
- Advanced Imaging Research Center, Oregon Health & Science University, Portland, Oregon, USA
| | - Daniel Schwartz
- Advanced Imaging Research Center, Oregon Health & Science University, Portland, Oregon, USA
| | - Andreas A Linninger
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, Illinois, USA
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois, USA
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8
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Ang PS, Zhang DM, Azizi SA, Norton de Matos SA, Brorson JR. The glymphatic system and cerebral small vessel disease. J Stroke Cerebrovasc Dis 2024; 33:107557. [PMID: 38198946 DOI: 10.1016/j.jstrokecerebrovasdis.2024.107557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 12/28/2023] [Accepted: 01/02/2024] [Indexed: 01/12/2024] Open
Abstract
OBJECTIVES Cerebral small vessel disease is a group of pathologies in which alterations of the brain's blood vessels contribute to stroke and neurocognitive changes. Recently, a neurotoxic waste clearance system composed of perivascular spaces abutting the brain's blood vessels, termed the glymphatic system, has been identified as a key player in brain homeostasis. Given that small vessel disease and the glymphatic system share anatomical structures, this review aims to reexamine small vessel disease in the context of the glymphatic system and highlight novel aspects of small vessel disease physiology. MATERIALS AND METHODS This review was conducted with an emphasis on studies that examined aspects of small vessel disease and on works characterizing the glymphatic system. We searched PubMed for relevant articles using the following keywords: glymphatics, cerebral small vessel disease, arterial pulsatility, hypertension, blood-brain barrier, endothelial dysfunction, stroke, diabetes. RESULTS Cerebral small vessel disease and glymphatic dysfunction are anatomically connected and significant risk factors are shared between the two. These include hypertension, type 2 diabetes, advanced age, poor sleep, obesity, and neuroinflammation. There is clear evidence that CSVD hinders the effective functioning of glymphatic system. CONCLUSION These shared risk factors, as well as the model of cerebral amyloid angiopathy pathogenesis, hint at the possibility that glymphatic dysfunction could independently contribute to the pathogenesis of cerebral small vessel disease. However, the current evidence supports a model of cascading dysfunction, wherein concurrent small vessel and glymphatic injury hinder glymphatic-mediated recovery and promote the progression of subclinical to clinical disease.
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Affiliation(s)
- Phillip S Ang
- University of Chicago Pritzker School of Medicine, Chicago, IL 60637, United States
| | - Douglas M Zhang
- University of Chicago Pritzker School of Medicine, Chicago, IL 60637, United States
| | - Saara-Anne Azizi
- University of Chicago Pritzker School of Medicine, Chicago, IL 60637, United States
| | | | - James R Brorson
- University of Chicago Pritzker School of Medicine, Chicago, IL 60637, United States; Department of Neurology, The University of Chicago, Chicago, IL 60637, United States.
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9
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Shang J, Li W, Zhang H, Wang W, Liu N, Gao D, Wang F, Yan X, Gao C, Sun R, Zhang H, Ma K, Shao F, Zhang J. C-kit controls blood-brain barrier permeability by regulating caveolae-mediated transcytosis after chronic cerebral hypoperfusion. Biomed Pharmacother 2024; 170:115778. [PMID: 38141279 DOI: 10.1016/j.biopha.2023.115778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 10/13/2023] [Accepted: 10/20/2023] [Indexed: 12/25/2023] Open
Abstract
Blood-brain barrier (BBB) dysfunction plays a pivotal role in the pathology of chronic cerebral hypoperfusion (CCH)-related neurodegenerative diseases. Continuous endothelial cells (EC) that line the blood vessels of the brain are important components of the BBB to strictly control the flow of substances and maintain the homeostatic environment of the brain. However, the molecular mechanisms from the perspective of EC-induced BBB dysfunction after CCH are largely unknown. In this study, the BBB function was assessed using immunostaining and transmission electron microscopy. The EC dysfunction profile was screened by using EC enrichment followed by RNA sequencing. After identified the key EC dysfunction factor, C-kit, we used the C-kit inhibition drug (imatinib) and C-kit down-regulation method (AAV-BR1-C-kit shRNA) to verify the role of C-kit on BBB integrity and EC transcytosis after CCH. Furthermore, we also activated C-kit with stem cell factor (SCF) to observe the effects of C-kit on BBB following CCH. We explored that macromolecular proteins entered the brain mainly through EC transcytosis after CCH and caused neuronal loss. Additionally, we identified receptor tyrosine kinase C-kit as a key EC dysfunction molecule. Furthermore, the pharmacological inhibition of C-kit with imatinib counteracted BBB leakage by reducing caveolae-mediated transcytosis. Moreover, treatment with AAV-BR1-C-kit shRNA, which targets brain EC to inhibit C-kit expression, also ameliorated BBB leakage by reducing caveolae-mediated transcytosis. Furthermore, the SCF increased the permeability of the BBB by actively increasing caveolae-mediated transcytosis. This study provides evidence that C-kit is a key BBB permeability regulator through caveolae-mediated transcytosis in EC after CCH.
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Affiliation(s)
- Junkui Shang
- Department of Neurology, Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, Henan 450003, China
| | - Wei Li
- Department of Neurology, Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, Henan 450003, China
| | - Huiwen Zhang
- Department of Neurology, Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, Henan 450003, China
| | - Wan Wang
- Department of Neurology, Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, Henan 450003, China
| | - Ning Liu
- Department of Neurology, Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, Henan 450003, China
| | - Dandan Gao
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, Hubei 430072, China
| | - Fengyu Wang
- Department of Neurology, Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, Henan 450003, China
| | - Xi Yan
- Department of Neurology, Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, Henan 450003, China
| | - Chenhao Gao
- Department of Neurology, Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, Henan 450003, China
| | - Ruihua Sun
- Department of Neurology, Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, Henan 450003, China
| | - Haohan Zhang
- Department of Neurology, Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, Henan 450003, China
| | - Kai Ma
- Department of Neurology, Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, Henan 450003, China
| | - Fengmin Shao
- Department of Neurology, Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, Henan 450003, China; Department of Nephrology, Henan Provincial Key Laboratory of Kidney Disease and Immunology, Henan Provincial People's Hospital, Zhengzhou University People's Hospital, Henan University People's Hospital, Zhengzhou, Henan 450003, China.
| | - Jiewen Zhang
- Department of Neurology, Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, Henan 450003, China.
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Bernardino de Paula R, Wenceslau CF, McCarthy CG. To err, K IR2 that is, on the side of vasodilation in aging. Am J Physiol Heart Circ Physiol 2023; 325:H1415-H1417. [PMID: 37861649 DOI: 10.1152/ajpheart.00670.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 10/19/2023] [Indexed: 10/21/2023]
Affiliation(s)
- Ricardo Bernardino de Paula
- Cardiovascular Translational Research Center and Department of Cell Biology and Anatomy, University of South Carolina School of Medicine, Columbia, South Carolina, United States
| | - Camilla F Wenceslau
- Cardiovascular Translational Research Center and Department of Cell Biology and Anatomy, University of South Carolina School of Medicine, Columbia, South Carolina, United States
| | - Cameron G McCarthy
- Cardiovascular Translational Research Center and Department of Cell Biology and Anatomy, University of South Carolina School of Medicine, Columbia, South Carolina, United States
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Polk FD, Hakim MA, Silva JF, Behringer EJ, Pires PW. Endothelial K IR2 channel dysfunction in aged cerebral parenchymal arterioles. Am J Physiol Heart Circ Physiol 2023; 325:H1360-H1372. [PMID: 37801044 PMCID: PMC10907073 DOI: 10.1152/ajpheart.00279.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 09/27/2023] [Accepted: 09/28/2023] [Indexed: 10/07/2023]
Abstract
Aging is associated with cognitive decline via incompletely understood mechanisms. Cerebral microvascular dysfunction occurs in aging, particularly impaired endothelium-mediated dilation. Parenchymal arterioles are bottlenecks of the cerebral microcirculation, and dysfunction causes a mismatch in nutrient demand and delivery, leaving neurons at risk. Extracellular nucleotides elicit parenchymal arteriole dilation by activating endothelial purinergic receptors (P2Y), leading to opening of K+ channels, including inwardly-rectifying K+ channels (KIR2). These channels amplify hyperpolarizing signals, resulting in dilation. However, it remains unknown if endothelial P2Y and KIR2 signaling are altered in brain parenchymal arterioles during aging. We hypothesized that aging impairs endothelial P2Y and KIR2 function in parenchymal arterioles. We observed reduced dilation to the purinergic agonist 2-methyl-S-ADP (1 µM) in arterioles from Aged (>24-month-old) mice when compared to Young (4-6 months of age) despite similar hyperpolarization in endothelial cells tubes. No differences were observed in vasodilation or endothelial cell hyperpolarization to activation of small- and intermediate-conductance Ca2+-activated K+ channels (KCa2.3 / KCa3.1) by NS309. Hyperpolarization to 15 mM [K+]E was smaller in Aged than Young mice, despite a paradoxical increased dilation in Aged arterioles to 15 mM [K+]E that was unchanged by endothelium removal. KIR2 Inhibition attenuated vasodilatory responses to 15 mM [K+]E and 1 µM 2-me-S-ADP in both Young and Aged arterioles. Further, we observed a significant increase in myogenic tone in Aged parenchymal arterioles, which was not enhanced by endothelium removal. We conclude that aging impairs endothelial KIR2 channel function in the cerebral microcirculation with possible compensation by smooth muscle cells.
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Affiliation(s)
- Felipe D Polk
- Department of Physiology, University of Arizona, Tucson, Arizona, United States
| | - Md A Hakim
- Loma Linda University, Loma Linda, CA, United States
| | - Josiane F Silva
- Physiology, University of Arizona, Tucson, Arizona, United States
| | - Erik J Behringer
- Basic Sciences, Loma Linda University, Loma Linda, CA, United States
| | - Paulo W Pires
- Physiology, University of Arizona, Tucson, AZ, United States
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12
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Fang X, Border JJ, Rivers PL, Zhang H, Williams JM, Fan F, Roman RJ. Amyloid beta accumulation in TgF344-AD rats is associated with reduced cerebral capillary endothelial Kir2.1 expression and neurovascular uncoupling. GeroScience 2023; 45:2909-2926. [PMID: 37326915 PMCID: PMC10643802 DOI: 10.1007/s11357-023-00841-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 05/25/2023] [Indexed: 06/17/2023] Open
Abstract
Alzheimer's disease (AD) exerts a tremendous socio-economic burden worldwide. Although reduced cerebral blood flow is an early and persistent symptom that precedes the loss of cognitive function in AD, the underlying molecular and cellular mechanisms remain unclear. The present study investigated whether capillary endothelial inward rectifier potassium 2 (Kir2.1) expression is reduced in TgF344-AD (AD) rats and contributes to neurovascular uncoupling and cognitive deficits in AD. Three- to fourteen-month-old AD rats expressing mutant human APP and PS1 and age-matched wild-type (WT) F344 rats were studied. AD rats exhibited higher amyloid beta (Aβ) expression in the brain as early as 3 months of age and amyloid plaques by 4 months of age. Functional hyperemic responses induced by whisker stimulation were impaired at 4 months of age, which were exacerbated in 6-month- and 14-month-old AD rats. The expression of Kir2.1 protein was significantly lower in the brains of 6-month-old AD versus WT rats, and Kir2.1 coverage was lower in the cerebral microvasculature of AD than in WT rats. Aβ1-42 reduced the Kir2.1 expression in cultured capillary endothelial cells. Cerebral parenchymal arterioles with attached capillaries exhibited a reduced vasodilator in response to 10 mM K+ applied to capillaries, and constricted less following administration of a Kir2.1 channel blocker, compared to WT vessels. These results indicate that capillary endothelial Kir2.1 expression is reduced and contributes to impaired functional hyperemia in AD rats at early ages, perhaps secondary to elevated Aβ expression.
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Affiliation(s)
- Xing Fang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Jane J Border
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Patrice L Rivers
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Huawei Zhang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Jan Michael Williams
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Fan Fan
- Department of Physiology, Medical College of Georgia, Augusta University, 1462 Laney Walker Blvd, Augusta, GA, 30912, USA.
| | - Richard J Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA.
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13
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Kalyuzhnaya Y, Khaitin A, Demyanenko S. Modeling transient ischemic attack via photothrombosis. Biophys Rev 2023; 15:1279-1286. [PMID: 37974996 PMCID: PMC10643708 DOI: 10.1007/s12551-023-01121-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 08/18/2023] [Indexed: 11/19/2023] Open
Abstract
The health significance of transient ischemic attacks (TIAs) is largely underestimated. Often, TIAs are not given significant importance, and in vain, because TIAs are a predictor of the development of serious cardiovascular diseases and even death. Because of this, and because of the difficulty in diagnosing the disease, TIAs and related microinfarcts are poorly investigated. Photothrombotic models of stroke and TIA allow reproducing the occlusion of small brain vessels, even single ones. When dosing the concentration of photosensitizer, intensity and irradiation time, it is possible to achieve occlusion of well-defined small vessels with high reproducibility, and with the help of modern methods of blood flow assessment it is possible to achieve spontaneous restoration of blood flow without vessel rupture. In this review, we discuss the features of microinfarcts and the contemporary experimental approaches used to model TIA and microinfarcts, with an emphasis on models using the principle of photothrombosis of brain vessels. We review modern techniques for in vivo detection of blood flow in small brain vessels, as well as biomarkers of microinfarcts.
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Affiliation(s)
- Y.N. Kalyuzhnaya
- Southern Federal University, Academy of Biology and Biotechnology, Rostov-on-Don, Russia
| | - A.M. Khaitin
- Southern Federal University, Academy of Biology and Biotechnology, Rostov-on-Don, Russia
| | - S.V. Demyanenko
- Southern Federal University, Academy of Biology and Biotechnology, Rostov-on-Don, Russia
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14
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Epp R, Glück C, Binder NF, El Amki M, Weber B, Wegener S, Jenny P, Schmid F. The role of leptomeningeal collaterals in redistributing blood flow during stroke. PLoS Comput Biol 2023; 19:e1011496. [PMID: 37871109 PMCID: PMC10621965 DOI: 10.1371/journal.pcbi.1011496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 11/02/2023] [Accepted: 09/03/2023] [Indexed: 10/25/2023] Open
Abstract
Leptomeningeal collaterals (LMCs) connect the main cerebral arteries and provide alternative pathways for blood flow during ischaemic stroke. This is beneficial for reducing infarct size and reperfusion success after treatment. However, a better understanding of how LMCs affect blood flow distribution is indispensable to improve therapeutic strategies. Here, we present a novel in silico approach that incorporates case-specific in vivo data into a computational model to simulate blood flow in large semi-realistic microvascular networks from two different mouse strains, characterised by having many and almost no LMCs between middle and anterior cerebral artery (MCA, ACA) territories. This framework is unique because our simulations are directly aligned with in vivo data. Moreover, it allows us to analyse perfusion characteristics quantitatively across all vessel types and for networks with no, few and many LMCs. We show that the occlusion of the MCA directly caused a redistribution of blood that was characterised by increased flow in LMCs. Interestingly, the improved perfusion of MCA-sided microvessels after dilating LMCs came at the cost of a reduced blood supply in other brain areas. This effect was enhanced in regions close to the watershed line and when the number of LMCs was increased. Additional dilations of surface and penetrating arteries after stroke improved perfusion across the entire vasculature and partially recovered flow in the obstructed region, especially in networks with many LMCs, which further underlines the role of LMCs during stroke.
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Affiliation(s)
- Robert Epp
- Institute of Fluid Dynamics, ETH Zurich, Zurich, Switzerland
| | - Chaim Glück
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Nadine Felizitas Binder
- Deptartment of Neurology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Mohamad El Amki
- Deptartment of Neurology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Susanne Wegener
- Deptartment of Neurology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Patrick Jenny
- Institute of Fluid Dynamics, ETH Zurich, Zurich, Switzerland
| | - Franca Schmid
- Institute of Fluid Dynamics, ETH Zurich, Zurich, Switzerland
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
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15
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Zedde M, Grisendi I, Assenza F, Vandelli G, Napoli M, Moratti C, Lochner P, Seiffge DJ, Piazza F, Valzania F, Pascarella R. The Venular Side of Cerebral Amyloid Angiopathy: Proof of Concept of a Neglected Issue. Biomedicines 2023; 11:2663. [PMID: 37893037 PMCID: PMC10604278 DOI: 10.3390/biomedicines11102663] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 09/23/2023] [Accepted: 09/25/2023] [Indexed: 10/29/2023] Open
Abstract
Small vessel diseases (SVD) is an umbrella term including several entities affecting small arteries, arterioles, capillaries, and venules in the brain. One of the most relevant and prevalent SVDs is cerebral amyloid angiopathy (CAA), whose pathological hallmark is the deposition of amyloid fragments in the walls of small cortical and leptomeningeal vessels. CAA frequently coexists with Alzheimer's Disease (AD), and both are associated with cerebrovascular events, cognitive impairment, and dementia. CAA and AD share pathophysiological, histopathological and neuroimaging issues. The venular involvement in both diseases has been neglected, although both animal models and human histopathological studies found a deposition of amyloid beta in cortical venules. This review aimed to summarize the available information about venular involvement in CAA, starting from the biological level with the putative pathomechanisms of cerebral damage, passing through the definition of the peculiar angioarchitecture of the human cortex with the functional organization and consequences of cortical arteriolar and venular occlusion, and ending to the hypothesized links between cortical venular involvement and the main neuroimaging markers of the disease.
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Affiliation(s)
- Marialuisa Zedde
- Neurology Unit, Stroke Unit, AUSL-IRCCS di Reggio Emilia, Via Amendola 2, 42122 Reggio Emilia, Italy
| | - Ilaria Grisendi
- Neurology Unit, Stroke Unit, AUSL-IRCCS di Reggio Emilia, Via Amendola 2, 42122 Reggio Emilia, Italy
| | - Federica Assenza
- Neurology Unit, Stroke Unit, AUSL-IRCCS di Reggio Emilia, Via Amendola 2, 42122 Reggio Emilia, Italy
| | - Gabriele Vandelli
- Neurology Unit, Stroke Unit, AUSL-IRCCS di Reggio Emilia, Via Amendola 2, 42122 Reggio Emilia, Italy
| | - Manuela Napoli
- Neuroradiology Unit, AUSL-IRCCS di Reggio Emilia, Via Amendola 2, 42122 Reggio Emilia, Italy
| | - Claudio Moratti
- Neuroradiology Unit, AUSL-IRCCS di Reggio Emilia, Via Amendola 2, 42122 Reggio Emilia, Italy
| | - Piergiorgio Lochner
- Department of Neurology, Saarland University Medical Center, 66421 Homburg, Germany;
| | - David J. Seiffge
- Department of Neurology, Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland
| | - Fabrizio Piazza
- CAA and AD Translational Research and Biomarkers Laboratory, School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900 Monza, Italy;
| | - Franco Valzania
- Neurology Unit, Stroke Unit, AUSL-IRCCS di Reggio Emilia, Via Amendola 2, 42122 Reggio Emilia, Italy
| | - Rosario Pascarella
- Neuroradiology Unit, AUSL-IRCCS di Reggio Emilia, Via Amendola 2, 42122 Reggio Emilia, Italy
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16
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Peleli M, Lyngso KS, Poulsen FR, Hansen PBL, Papapetropoulos A, Stubbe J. Inhibition of cystathionine-gamma lyase dampens vasoconstriction in mouse and human intracerebral arterioles. Acta Physiol (Oxf) 2023; 239:e14021. [PMID: 37555636 DOI: 10.1111/apha.14021] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 06/11/2023] [Accepted: 07/04/2023] [Indexed: 08/10/2023]
Abstract
AIM In extracerebral vascular beds cystathionine-gamma lyase (CSE) activity plays a vasodilatory role but the role of this hydrogen sulfide (H2 S) producing enzyme in the intracerebral arterioles remain poorly understood. We hypothesized a similar function in the intracerebral arterioles. METHODS Intracerebral arterioles were isolated from wild type C57BL/6J mouse (9-12 months old) brains and from human brain biopsies. The function (contractility and secondary dilatation) of the intracerebral arterioles was tested ex vivo by pressure myography using a perfusion set-up. Reverse transcription polymerase chain reaction was used for detecting CSE expression. RESULTS CSE is expressed in human and mouse intracerebral arterioles. CSE inhibition with L-propargylglycine (PAG) significantly dampened the K+ -induced vasoconstriction in intracerebral arterioles of both species (% of maximum contraction: in human control: 45.4 ± 2.7 versus PAG: 27 ± 5.2 and in mouse control: 50 ± 1.5 versus PAG: 33 ± 5.2) but did not affect the secondary dilatation. This effect of PAG was significantly reversed by the H2 S donor sodium hydrosulfide (NaSH) in human (PAG + NaSH: 38.8 ± 7.2) and mouse (PAG + NaSH: 41.7 ± 3.1) arterioles, respectively. The endothelial NO synthase (eNOS) inhibitor, Nω-Nitro-l-arginine methyl ester (L-NAME), and the inhibitor of soluble guanylate cyclase (sGC), 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) reversed the effect of PAG on the K+ -induced vasoconstriction in the mouse arterioles and attenuated the K+ -induced secondary dilatation significantly. CONCLUSION CSE contributes to the K+ -induced vasoconstriction via a mechanism involving H2 S, eNOS, and sGC whereas the secondary dilatation is regulated by eNOS and sGC but not by CSE.
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Affiliation(s)
- Maria Peleli
- Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
- Laboratory of Pharmacology, Department of Pharmacy, National and Kapodistrian University of Athens, Athens, Greece
- Clinical, Experimental Surgery and Translational Research Center, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Kristina S Lyngso
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Frantz Rom Poulsen
- Department of Neurosurgery, Odense University Hospital, Odense, Denmark
- Department of Clinical Research, University of Southern Denmark and BRIDGE (Brain Research-Interdisciplinary Guided Excellence), Odense, Denmark
- OPEN - Odense Patient Data Explorative Network, Odense, Denmark
| | - Pernille B L Hansen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Andreas Papapetropoulos
- Laboratory of Pharmacology, Department of Pharmacy, National and Kapodistrian University of Athens, Athens, Greece
- Clinical, Experimental Surgery and Translational Research Center, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Jane Stubbe
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
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17
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Jeffrey DA, Russell A, Guerrero MB, Fontaine JT, Romero P, Rosehart AC, Dabertrand F. Estrogen regulates myogenic tone in hippocampal arterioles by enhanced basal release of nitric oxide and endothelial SK Ca channel activity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.15.553442. [PMID: 37645715 PMCID: PMC10462022 DOI: 10.1101/2023.08.15.553442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Arteries and arterioles exhibit myogenic tone, a partially constricted state that allows further constriction or dilation in response to moment-to-moment fluctuations in blood pressure. The vascular endothelium that lines the internal surface of all blood vessels controls a wide variety of essential functions, including the contractility of the adjacent smooth muscle cells by providing a tonic vasodilatory influence. Studies conducted on large (pial) arteries on the surface of the brain have shown that estrogen lowers myogenic tone in female mice by enhancing nitric oxide (NO) release from the endothelium, however, whether this difference extends to the intracerebral microcirculation remains ambiguous. The existing incomplete picture of sex differences in cerebrovascular physiology combined with a deficiency in treatments that fully restore cognitive function after cerebrovascular accidents places heavy emphasis on the necessity to investigate myogenic tone regulation in the microcirculation from both male and female mice. We hypothesized that sex-linked hormone regulation of myogenic tone extends its influence on the microcirculation level, and sought to characterize it in isolated arterioles from the hippocampus, a major cognitive brain area. Using diameter measurements both in vivo (acute cranial window vascular diameter) and ex vivo (pressure myography experiments), we measured lower myogenic tone responses in hippocampal arterioles from female than male mice. By using a combined surgical and pharmacological approach, we found myogenic tone in ovariectomized (OVX) female mice matches that of males, as well as in endothelium-denuded arterioles. Interestingly, eNOS inhibition induced a larger constriction in female arterioles but only partially abolished the difference in tone. We identified that the remnant difference was mediated by a higher activity and expression of the small-conductance Ca 2+ -sensitive K + (SK) channels. Collectively, these data indicate that eNOS and SK channels exert greater vasodilatory influence over myogenic tone in female mice at physiological pressures.
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18
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Li J, Wu X, Fu Y, Nie H, Tang Z. Two-photon microscopy: application advantages and latest progress for in vivo imaging of neurons and blood vessels after ischemic stroke. Rev Neurosci 2023; 34:559-572. [PMID: 36719181 DOI: 10.1515/revneuro-2022-0127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Accepted: 01/02/2023] [Indexed: 02/01/2023]
Abstract
Two-photon microscopy (TPM) plays an important role in the study of the changes of the two important components of neurovascular units (NVU) - neurons and blood vessels after ischemic stroke (IS). IS refers to sudden neurological dysfunction caused by focal cerebral ischemia, which is one of the leading causes of death and disability worldwide. TPM is a new and rapidly developing high-resolution real-time imaging technique used in vivo that has attracted increasing attention from scientists in the neuroscience field. Neurons and blood vessels are important components of neurovascular units, and they undergo great changes after IS to respond to and compensate for ischemic injury. Here, we introduce the characteristics and pre-imaging preparations of TPM, and review the common methods and latest progress of TPM in the neuronal and vascular research for injury and recovery of IS in recent years. With the review, we clearly recognized that the most important advantage of TPM in the study of ischemic stroke is the ability to perform chronic longitudinal imaging of different tissues at a high resolution in vivo. Finally, we discuss the limitations of TPM and the technological advances in recent years.
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Affiliation(s)
- Jiarui Li
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, P. R. China
| | - Xuan Wu
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, P. R. China
| | - Yu Fu
- Department of Geriatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, P. R. China
| | - Hao Nie
- Department of Geriatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, P. R. China
| | - Zhouping Tang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, P. R. China
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19
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Inoue Y, Shue F, Bu G, Kanekiyo T. Pathophysiology and probable etiology of cerebral small vessel disease in vascular dementia and Alzheimer's disease. Mol Neurodegener 2023; 18:46. [PMID: 37434208 PMCID: PMC10334598 DOI: 10.1186/s13024-023-00640-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 06/28/2023] [Indexed: 07/13/2023] Open
Abstract
Vascular cognitive impairment and dementia (VCID) is commonly caused by vascular injuries in cerebral large and small vessels and is a key driver of age-related cognitive decline. Severe VCID includes post-stroke dementia, subcortical ischemic vascular dementia, multi-infarct dementia, and mixed dementia. While VCID is acknowledged as the second most common form of dementia after Alzheimer's disease (AD) accounting for 20% of dementia cases, VCID and AD frequently coexist. In VCID, cerebral small vessel disease (cSVD) often affects arterioles, capillaries, and venules, where arteriolosclerosis and cerebral amyloid angiopathy (CAA) are major pathologies. White matter hyperintensities, recent small subcortical infarcts, lacunes of presumed vascular origin, enlarged perivascular space, microbleeds, and brain atrophy are neuroimaging hallmarks of cSVD. The current primary approach to cSVD treatment is to control vascular risk factors such as hypertension, dyslipidemia, diabetes, and smoking. However, causal therapeutic strategies have not been established partly due to the heterogeneous pathogenesis of cSVD. In this review, we summarize the pathophysiology of cSVD and discuss the probable etiological pathways by focusing on hypoperfusion/hypoxia, blood-brain barriers (BBB) dysregulation, brain fluid drainage disturbances, and vascular inflammation to define potential diagnostic and therapeutic targets for cSVD.
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Affiliation(s)
- Yasuteru Inoue
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Francis Shue
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Guojun Bu
- SciNeuro Pharmaceuticals, Rockville, MD 20850 USA
| | - Takahisa Kanekiyo
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
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20
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Urner TM, Cowdrick KR, Brothers RO, Boodooram T, Zhao H, Goyal V, Sathialingam E, Quadri A, Turrentine K, Akbar MM, Triplett SE, Bai S, Buckley EM. Normative cerebral microvascular blood flow waveform morphology assessed with diffuse correlation spectroscopy. BIOMEDICAL OPTICS EXPRESS 2023; 14:3635-3653. [PMID: 37497521 PMCID: PMC10368026 DOI: 10.1364/boe.489760] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/05/2023] [Accepted: 05/20/2023] [Indexed: 07/28/2023]
Abstract
Microvascular cerebral blood flow exhibits pulsatility at the cardiac frequency that carries valuable information about cerebrovascular health. This study used diffuse correlation spectroscopy to quantify normative features of these waveforms in a cohort of thirty healthy adults. We demonstrate they are sensitive to changes in vascular tone, as indicated by pronounced morphological changes with hypercapnia. Further, we observe significant sex-based differences in waveform morphology, with females exhibiting higher flow, greater area-under-the-curve, and lower pulsatility. Finally, we quantify normative values for cerebral critical closing pressure, i.e., the minimum pressure required to maintain flow in a given vascular region.
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Affiliation(s)
- Tara M Urner
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30322, USA
| | - Kyle R Cowdrick
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30322, USA
| | - Rowan O Brothers
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30322, USA
| | - Tisha Boodooram
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30322, USA
| | - Hongting Zhao
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30322, USA
| | - Vidisha Goyal
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30322, USA
| | - Eashani Sathialingam
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30322, USA
| | - Ayesha Quadri
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30322, USA
| | - Katherine Turrentine
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30322, USA
| | - Mariam M Akbar
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30322, USA
| | - Sydney E Triplett
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30322, USA
| | - Shasha Bai
- Department of Pediatrics, Emory School of Medicine, Atlanta, GA 30322, USA
| | - Erin M Buckley
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30322, USA
- Department of Pediatrics, Emory School of Medicine, Atlanta, GA 30322, USA
- Children's Research Scholar, Children's Healthcare of Atlanta, 2015 Uppergate Dr., Atlanta, GA 30322, USA
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21
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Hwang J, Koun S, Ha Y, Jung JM. Zebrafish thrombosis models according to the location of thrombus formation. ANNALS OF TRANSLATIONAL MEDICINE 2023; 11:309. [PMID: 37404988 PMCID: PMC10316102 DOI: 10.21037/atm-22-1265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 04/14/2023] [Indexed: 07/06/2023]
Abstract
Background Ischemic stroke becomes a major cause of death and disability. It can develop due to intravascular or cardiac thromboemboli. Animal models that reflect diverse stroke mechanisms remain under development. Using photochemical thrombosis, we developed a feasible zebrafish model according to the thrombus location (intracerebral vs. intracardiac). We validated the model using real-time imaging and thrombolytic agent. Methods We used transgenic zebrafish larvae (flk:gfp), which express specific fluorescence in endothelial cells. We injected Rose Bengal, a photosensitizer as a mixture of photosensitizer, and a fluorescent agent into the cardinal vein of the larvae. We then evaluated real-time thrombosis in vivo by inducing thrombosis through exposure to a confocal laser (560 nm) and staining the blood flow (RITC-dextran). We validated intracerebral and intracardiac thrombotic models with checking the activity of tissue plasminogen activator (tPA). Results The photochemical agent induced the formation of intracerebral thrombi in transgenic zebrafish. Real-time imaging techniques confirmed the formation of the thrombi. The damage and apoptosis of the vessel's endothelial cells were seen in the in vivo model. An intracardiac thrombosis model was developed by the same method using photothrombosis, and the model was validated through thrombolysis by tPA. Conclusions We developed and validated two zebrafish thrombosis models that are readily available, cost-effective, and intuitive for assessing the efficacy of thrombolytic agents. These models can be used for a broad spectrum of future studies, such as screening and efficacy assessment of new antithrombotic agents.
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Affiliation(s)
- Jinwook Hwang
- Department of Thoracic and Cardiovascular Surgery, Korea University Ansan Hospital, Korea University College of Medicine, Ansan, Republic of Korea
| | - Soonil Koun
- Biomedical Research Center, Korea University Ansan Hospital, Korea University College of Medicine, Ansan, Republic of Korea
| | - Youngran Ha
- Department of Neurology, Korea University Ansan Hospital, Korea University College of Medicine, Ansan, Republic of Korea
| | - Jin-Man Jung
- Department of Neurology, Korea University Ansan Hospital, Korea University College of Medicine, Ansan, Republic of Korea
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22
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Deán-Ben XL, Robin J, Nozdriukhin D, Ni R, Zhao J, Glück C, Droux J, Sendón-Lago J, Chen Z, Zhou Q, Weber B, Wegener S, Vidal A, Arand M, El Amki M, Razansky D. Deep optoacoustic localization microangiography of ischemic stroke in mice. Nat Commun 2023; 14:3584. [PMID: 37328490 PMCID: PMC10275987 DOI: 10.1038/s41467-023-39069-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 05/24/2023] [Indexed: 06/18/2023] Open
Abstract
Super-resolution optoacoustic imaging of microvascular structures deep in mammalian tissues has so far been impeded by strong absorption from densely-packed red blood cells. Here we devised 5 µm biocompatible dichloromethane-based microdroplets exhibiting several orders of magnitude higher optical absorption than red blood cells at near-infrared wavelengths, thus enabling single-particle detection in vivo. We demonstrate non-invasive three-dimensional microangiography of the mouse brain beyond the acoustic diffraction limit (<20 µm resolution). Blood flow velocity quantification in microvascular networks and light fluence mapping was also accomplished. In mice affected by acute ischemic stroke, the multi-parametric multi-scale observations enabled by super-resolution and spectroscopic optoacoustic imaging revealed significant differences in microvascular density, flow and oxygen saturation in ipsi- and contra-lateral brain hemispheres. Given the sensitivity of optoacoustics to functional, metabolic and molecular events in living tissues, the new approach paves the way for non-invasive microscopic observations with unrivaled resolution, contrast and speed.
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Affiliation(s)
- Xosé Luís Deán-Ben
- Institute of Pharmacology and Toxicology and Institute for Biomedical Engineering, Faculty of Medicine, University of Zurich, Zurich, Switzerland.
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland.
| | - Justine Robin
- Institute of Pharmacology and Toxicology and Institute for Biomedical Engineering, Faculty of Medicine, University of Zurich, Zurich, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland
| | - Daniil Nozdriukhin
- Institute of Pharmacology and Toxicology and Institute for Biomedical Engineering, Faculty of Medicine, University of Zurich, Zurich, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland
| | - Ruiqing Ni
- Institute of Pharmacology and Toxicology and Institute for Biomedical Engineering, Faculty of Medicine, University of Zurich, Zurich, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland
- Zurich Neuroscience Center, Zurich, Switzerland
| | - Jim Zhao
- Institute of Pharmacology and Toxicology and Institute for Biomedical Engineering, Faculty of Medicine, University of Zurich, Zurich, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland
| | - Chaim Glück
- Experimental Imaging and Neuroenergetics, Institute of Pharmacology and Toxicology, University of Zurich, and Zurich Neuroscience Center, Zurich, Switzerland
| | - Jeanne Droux
- Zurich Neuroscience Center, Zurich, Switzerland
- Department of Neurology, University Hospital and University of Zurich and University of Zurich, Zurich, Switzerland
| | - Juan Sendón-Lago
- Experimental Biomedicine Centre (CEBEGA), University of Santiago de Compostela, Santiago de Compostela, Spain
| | - Zhenyue Chen
- Institute of Pharmacology and Toxicology and Institute for Biomedical Engineering, Faculty of Medicine, University of Zurich, Zurich, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland
| | - Quanyu Zhou
- Institute of Pharmacology and Toxicology and Institute for Biomedical Engineering, Faculty of Medicine, University of Zurich, Zurich, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland
| | - Bruno Weber
- Experimental Imaging and Neuroenergetics, Institute of Pharmacology and Toxicology, University of Zurich, and Zurich Neuroscience Center, Zurich, Switzerland
| | - Susanne Wegener
- Zurich Neuroscience Center, Zurich, Switzerland
- Department of Neurology, University Hospital and University of Zurich and University of Zurich, Zurich, Switzerland
| | - Anxo Vidal
- Center for Research in Molecular Medicine and Chronic Diseases (CiMUS), University of Santiago de Compostela, Santiago de Compostela, Spain
| | - Michael Arand
- Institute of Pharmacology and Toxicology and Institute for Biomedical Engineering, Faculty of Medicine, University of Zurich, Zurich, Switzerland
| | - Mohamad El Amki
- Zurich Neuroscience Center, Zurich, Switzerland
- Department of Neurology, University Hospital and University of Zurich and University of Zurich, Zurich, Switzerland
| | - Daniel Razansky
- Institute of Pharmacology and Toxicology and Institute for Biomedical Engineering, Faculty of Medicine, University of Zurich, Zurich, Switzerland.
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland.
- Zurich Neuroscience Center, Zurich, Switzerland.
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23
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Fang X, Tang C, Zhang H, Border JJ, Liu Y, Shin SM, Yu H, Roman RJ, Fan F. Longitudinal characterization of cerebral hemodynamics in the TgF344-AD rat model of Alzheimer's disease. GeroScience 2023; 45:1471-1490. [PMID: 36933144 PMCID: PMC10400494 DOI: 10.1007/s11357-023-00773-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 03/12/2023] [Indexed: 03/19/2023] Open
Abstract
Alzheimer's disease (AD) is a global healthcare crisis. The TgF344-AD rat is an AD model exhibiting age-dependent AD pathological hallmarks. We confirmed that AD rats developed cognitive deficits at 6 months without alteration of any other major biophysical parameters. We longitudinally characterized cerebral hemodynamics in AD rats at 3, 4, 6, and 14 months. The myogenic responses of the cerebral arteries and arterioles were impaired at 4 months of age in the AD rats. Consistent with the ex vivo results, the AD rat exhibited poor autoregulation of surface and deep cortical cerebral blood flow 2 months preceding cognitive decline. The dysfunction of cerebral hemodynamics in AD is exacerbated with age associated with reduced cerebral perfusion. Further, abolished cell contractility contributes to cerebral hemodynamics imbalance in AD. This may be attributed to enhanced ROS production, reduced mitochondrial respiration and ATP production, and disrupted actin cytoskeleton in cerebral vascular contractile cells.
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Affiliation(s)
- Xing Fang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Chengyun Tang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
- Department of Physiology, Medical College of Georgia, Augusta University, 1462 Laney Walker Blvd, Augusta, GA, 30912, USA
| | - Huawei Zhang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Jane J Border
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Yedan Liu
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Seung Min Shin
- Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI, 53226, USA
| | - Hongwei Yu
- Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI, 53226, USA
| | - Richard J Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA.
- Department of Physiology, Medical College of Georgia, Augusta University, 1462 Laney Walker Blvd, Augusta, GA, 30912, USA.
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24
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Bennett HC, Zhang Q, Wu YT, Chon U, Pi HJ, Drew PJ, Kim Y. Aging drives cerebrovascular network remodeling and functional changes in the mouse brain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.23.541998. [PMID: 37305850 PMCID: PMC10257218 DOI: 10.1101/2023.05.23.541998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Aging is the largest risk factor for neurodegenerative disorders, and commonly associated with compromised cerebrovasculature and pericytes. However, we do not know how normal aging differentially impacts the vascular structure and function in different brain areas. Here we utilize mesoscale microscopy methods (serial two-photon tomography and light sheet microscopy) and in vivo imaging (wide field optical spectroscopy and two-photon imaging) to determine detailed changes in aged cerebrovascular networks. Whole-brain vascular tracing showed an overall ~10% decrease in vascular length and branching density, and light sheet imaging with 3D immunolabeling revealed increased arteriole tortuosity in aged brains. Vasculature and pericyte densities showed significant reductions in the deep cortical layers, hippocampal network, and basal forebrain areas. Moreover, in vivo imaging in awake mice identified delays in neurovascular coupling and disrupted blood oxygenation. Collectively, we uncover regional vulnerabilities of cerebrovascular network and physiological changes that can mediate cognitive decline in normal aging.
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Affiliation(s)
- Hannah C Bennett
- Department of Neural and Behavioral Sciences, The Pennsylvania State University, Hershey, PA, 17033, USA
- Equal contribution
| | - Qingguang Zhang
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, 16802, USA
- Equal contribution
| | - Yuan-Ting Wu
- Department of Neural and Behavioral Sciences, The Pennsylvania State University, Hershey, PA, 17033, USA
| | - Uree Chon
- Department of Neural and Behavioral Sciences, The Pennsylvania State University, Hershey, PA, 17033, USA
| | - Hyun-Jae Pi
- Department of Neural and Behavioral Sciences, The Pennsylvania State University, Hershey, PA, 17033, USA
| | - Patrick J Drew
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, 16802, USA
- Biomedical Engineering, Biology, and Neurosurgery, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Yongsoo Kim
- Department of Neural and Behavioral Sciences, The Pennsylvania State University, Hershey, PA, 17033, USA
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, 16802, USA
- Lead contact
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25
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Zhu L, Wang M, Liu Y, Fu P, Zhang W, Zhang H, Roe AW, Xi W. Single-microvessel occlusion produces lamina-specific microvascular flow vasodynamics and signs of neurodegenerative change. Cell Rep 2023; 42:112469. [PMID: 37141094 DOI: 10.1016/j.celrep.2023.112469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 01/12/2023] [Accepted: 04/18/2023] [Indexed: 05/05/2023] Open
Abstract
Recent studies have highlighted the importance of understanding the architecture and function of microvasculature, and dysfunction of these microvessels may underlie neurodegenerative disease. Here, we utilize a high-precision ultrafast laser-induced photothrombosis (PLP) method to occlude single capillaries and then quantitatively study the effects on vasodynamics and surrounding neurons. Analysis of the microvascular architecture and hemodynamics after single-capillary occlusion reveals distinct changes upstream vs. downstream branches, which shows rapid regional flow redistribution and local downstream blood-brain barrier (BBB) leakage. Focal ischemia via capillary occlusions surrounding labeled target neurons induces dramatic and rapid lamina-specific changes in neuronal dendritic architecture. Further, we find that micro-occlusion at two different depths within the same vascular arbor results in distinct effects on flow profiles in layers 2/3 vs layer 4. The current results reveal laminar-scale regulation distinctions in microinfarct response and raise the possibility that relatively greater impacts on microvascular function contribute to cognitive decline in neurodegenerative disease.
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Affiliation(s)
- Liang Zhu
- Interdisciplinary Institute of Neuroscience and Technology (ZIINT), The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310020, China; Interdisciplinary Institute of Neuroscience and Technology (ZIINT), College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou 310027, China
| | - Mengqi Wang
- Interdisciplinary Institute of Neuroscience and Technology (ZIINT), The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310020, China
| | - Yin Liu
- Interdisciplinary Institute of Neuroscience and Technology (ZIINT), The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310020, China
| | - Peng Fu
- Interdisciplinary Institute of Neuroscience and Technology (ZIINT), The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310020, China
| | - Weijie Zhang
- Interdisciplinary Institute of Neuroscience and Technology (ZIINT), College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou 310027, China
| | - Hequn Zhang
- Interdisciplinary Institute of Neuroscience and Technology (ZIINT), The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310020, China
| | - Anna Wang Roe
- Interdisciplinary Institute of Neuroscience and Technology (ZIINT), The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310020, China; MOE Frontier Science Center for Brain Research and Brain Machine Integration, Zhejiang University, Hangzhou 310058, China; Key Laboratory of Biomedical Engineering of the Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou 310027, China.
| | - Wang Xi
- Interdisciplinary Institute of Neuroscience and Technology (ZIINT), The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310020, China; MOE Frontier Science Center for Brain Research and Brain Machine Integration, Zhejiang University, Hangzhou 310058, China; Key Laboratory of Biomedical Engineering of the Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou 310027, China.
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26
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Qiu B, Zhao Z, Wang N, Feng Z, Chen XJ, Chen W, Sun W, Ge WP, Wang Y. A systematic observation of vasodynamics from different segments along the cerebral vasculature in the penumbra zone of awake mice following cerebral ischemia and recanalization. J Cereb Blood Flow Metab 2023; 43:665-679. [PMID: 36524693 PMCID: PMC10108196 DOI: 10.1177/0271678x221146128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 11/09/2022] [Accepted: 11/14/2022] [Indexed: 12/23/2022]
Abstract
Different segments of the cerebral vascular network may react distinctly to brain ischemia and recanalization. However, there are limited systematic observations of these vascular responses in mice under a physiological state following ischemic stroke. Herein, we aimed to investigate the vasodynamics among several segments along the cerebral vessels in awake mice following cerebral ischemia/recanalization via two-photon imaging. Plasma in the blood vessels were labelled with fluorescein isothiocyanate dextran. Smooth muscle cells and pericytes were labelled via a genetic mouse line (PDGFRβ-tdTomato). We observed a no-reflow phenomenon in downstream microcirculation, and the vasodynamics of different segments of larger cerebral vessels varied in the penumbra area following cerebral ischemia-reperfusion. Despite obtaining reperfusion from the middle cerebral artery, there were significant constrictions of the downstream blood vessels in the ischemic penumbra zone. Interestingly, we observed an extensive constriction of the capillaries 3 hours following recanalization, both at the site covered by pericyte soma and by the pericyte process alone. In addition, we did not observe a significant positive correlation between the changed capillary diameter and pericyte coverage along the capillary. Taken together, abnormal constrictions and vasodynamics of cerebral large and small vessels may directly contribute to microcirculation failure following recanalization in ischemic stroke.
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Affiliation(s)
- Baoshan Qiu
- Department of Neurology, Beijing Tiantan
Hospital, Capital Medical University, Beijing, China
- Chinese Institute for Brain Research,
Beijing, China
| | - Zichen Zhao
- Department of Neurology, Beijing Tiantan
Hospital, Capital Medical University, Beijing, China
- Chinese Institute for Brain Research,
Beijing, China
| | - Nan Wang
- Department of Neurology, Beijing Tiantan
Hospital, Capital Medical University, Beijing, China
- Chinese Institute for Brain Research,
Beijing, China
| | - Ziyan Feng
- Chinese Institute for Brain Research,
Beijing, China
| | - Xing-jun Chen
- Chinese Institute for Brain Research,
Beijing, China
- Academy for Advanced Interdisciplinary
Studies (AAIS), Peking University, Beijing, China
| | - Weiqi Chen
- Department of Neurology, Beijing Tiantan
Hospital, Capital Medical University, Beijing, China
| | - Wenzhi Sun
- Chinese Institute for Brain Research,
Beijing, China
- School of Basic Medical Sciences, Capital
Medical University, Beijing, China
| | - Woo-ping Ge
- Chinese Institute for Brain Research,
Beijing, China
| | - Yilong Wang
- Department of Neurology, Beijing Tiantan
Hospital, Capital Medical University, Beijing, China
- Chinese Institute for Brain Research,
Beijing, China
- China National Clinical Research Centre for
Neurological Diseases, Beijing, China
- Advanced Innovation Centre for Human Brain
Protection, Capital Medical University, Beijing, China
- National Centre for Neurological Diseases,
Beijing, China
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27
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Liu Z, He B, Wang X, Peng J, Sun Q, Luo C. Deep cortical microinfarction induced by femtosecond laser in mice: Long-term secondary pathological changes in corresponding superficial cortex. Neurosci Lett 2023; 802:137170. [PMID: 36898650 DOI: 10.1016/j.neulet.2023.137170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 02/19/2023] [Accepted: 03/06/2023] [Indexed: 03/11/2023]
Abstract
BACKGROUND AND PURPOSE Previous studies have explored the clinical consequences of cortical microinfarction, mainly age-related cognitive decline. However, functional impairment of deep cortical microinfarction remains poorly understood. Based on anatomical knowledge and previous research, we infer that damage to the deep cortex may lead to cognitive deficits and communication impairment between the superficial cortex and thalamus. This study aimed to develop a new model of deep cortical microinfarction based on femtosecond laser ablation of a perforating artery. METHODS Twenty-eight mice were anesthetized with isoflurane, and a cranial window was thinned using a microdrill. Intensively focused femtosecond laser pulses were used to produce perforating arteriolar occlusions and ischemic brain damage was examined using histological analysis. RESULTS Occlusion of different perforating arteries induced different types of cortical microinfarctions. Blocking the perforating artery, which enters the cerebral cortex vertically and has no branches within 300 μm below, can result in deep cortical microinfarction. Moreover, this model showed neuronal loss and microglial activation in the lesions as well as dysplasia of nerve fibers and β-amyloid deposition in the corresponding superficial cortex. CONCLUSIONS We present here a new model of deep cortical microinfarction in mice, in which specific perforating arteries are selectively occluded by a femtosecond laser, and we preliminarily observe several long-term effects related to cognition. This animal model is helpful in investigating the pathophysiology of deep cerebral microinfarction. However, further clinical and experimental studies are required to explore deep cortical microinfarctions in greater molecular and physiological detail.
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Affiliation(s)
- Zhoujing Liu
- Department of Neurology, The Seventh Affiliated Hospital, Sun Yat-Sen University, No. 628 Zhenyuan Road, Shenzhen 518017, China
| | - Baixuan He
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-Sen University, No. 107 Yan Jiang West Road, Guangzhou 510120, China
| | - Xuemin Wang
- Department of Neurology, The Seventh Affiliated Hospital, Sun Yat-Sen University, No. 628 Zhenyuan Road, Shenzhen 518017, China
| | - Jiamin Peng
- Department of Neurology, The Seventh Affiliated Hospital, Sun Yat-Sen University, No. 628 Zhenyuan Road, Shenzhen 518017, China
| | - Qiaosong Sun
- Department of Neurology, The Seventh Affiliated Hospital, Sun Yat-Sen University, No. 628 Zhenyuan Road, Shenzhen 518017, China.
| | - Chuanming Luo
- Department of Neurology, The Seventh Affiliated Hospital, Sun Yat-Sen University, No. 628 Zhenyuan Road, Shenzhen 518017, China.
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28
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Kara B, Gordon MN, Gifani M, Dorrance AM, Counts SE. Vascular and Nonvascular Mechanisms of Cognitive Impairment and Dementia. Clin Geriatr Med 2023; 39:109-122. [PMID: 36404024 PMCID: PMC10062062 DOI: 10.1016/j.cger.2022.07.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Aging, familial gene mutations, and genetic, environmental, and modifiable lifestyle risk factors predispose individuals to cognitive impairment or dementia by influencing the efficacy of multiple, often interdependent cellular and molecular homeostatic pathways mediating neuronal, glial, and vascular integrity and, ultimately, cognitive status. This review summarizes data from foundational and recent breakthrough studies to highlight common and differential vascular and nonvascular pathogenic mechanisms underlying the progression of Alzheimer disease, vascular dementia, frontotemporal dementia, and dementia with Lewy bodies.
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Affiliation(s)
- Betul Kara
- Department of Translational Neuroscience, Michigan State University, 400 Monroe Avenue Northwest, Grand Rapids, MI 49503, USA
| | - Marcia N Gordon
- Department of Translational Neuroscience, Michigan State University, 400 Monroe Avenue Northwest, Grand Rapids, MI 49503, USA
| | - Mahsa Gifani
- Department of Translational Neuroscience, Michigan State University, 400 Monroe Avenue Northwest, Grand Rapids, MI 49503, USA
| | - Anne M Dorrance
- Department of Pharmacology and Toxicology, Michigan State University, 1355 Bogue Street, East Lansing, MI 48824, USA
| | - Scott E Counts
- Department of Translational Neuroscience, Michigan State University, 400 Monroe Avenue Northwest, Grand Rapids, MI 49503, USA; Department of Family Medicine, Michigan State University, 15 Michigan Street Northeast, Grand Rapids, MI 49503, USA; Hauenstein Neurosciences Center, Mercy Health Saint Mary's Medical Center, 20 Jefferson Avenue Southeast, Grand Rapids, MI 49503, USA.
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29
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Wang S, Tang C, Liu Y, Border JJ, Roman RJ, Fan F. Impact of impaired cerebral blood flow autoregulation on cognitive impairment. FRONTIERS IN AGING 2022; 3:1077302. [PMID: 36531742 PMCID: PMC9755178 DOI: 10.3389/fragi.2022.1077302] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 11/23/2022] [Indexed: 11/16/2023]
Abstract
Although the causes of cognitive impairment are multifactorial, emerging evidence indicates that cerebrovascular dysfunction plays an essential role in dementia. One of the most critical aspects of cerebrovascular dysfunction is autoregulation of cerebral blood flow (CBF), mainly mediated by the myogenic response, which is often impaired in dementia individuals with comorbidities, such as diabetes and hypertension. However, many unsolved questions remain. How do cerebrovascular networks coordinately modulate CBF autoregulation in health and disease? Does poor CBF autoregulation have an impact on cognitive impairment, and what are the underlying mechanisms? This review summarizes the cerebral vascular structure and myogenic (a three-phase model), metabolic (O2, CO2, adenosine, and H+), and endothelial (shear stress) factors in the regulation of CBF; and the consequences of CBF dysautoregulation. Other factors contributing to cerebrovascular dysfunction, such as impaired functional hyperemia and capillary abnormalities, are included as well. Moreover, this review highlights recent studies from our lab in terms of novel mechanisms involved in CBF autoregulation and addresses a hypothesis that there is a three-line of defense for CBF autoregulation in the cerebral vasculature.
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Affiliation(s)
- Shaoxun Wang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, United States
| | - Chengyun Tang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, United States
| | - Yedan Liu
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, United States
| | - Jane J Border
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, United States
| | - Richard J Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, United States
| | - Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, United States
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30
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Seiffge DJ, Polymeris AA, Law ZK, Krishnan K, Zietz A, Thilemann S, Werring D, Al-Shahi Salman R, Dineen RA, Engelter ST, Bath PM, Sprigg N, Lyrer P, Peters N. Cerebral Amyloid Angiopathy and the Risk of Hematoma Expansion. Ann Neurol 2022; 92:921-930. [PMID: 36054211 PMCID: PMC9804369 DOI: 10.1002/ana.26481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 08/09/2022] [Accepted: 08/12/2022] [Indexed: 01/05/2023]
Abstract
OBJECTIVE We assessed whether hematoma expansion (HE) and favorable outcome differ according to type of intracerebral hemorrhage (ICH). METHODS Among participants with ICH enrolled in the TICH-2 (Tranexamic Acid for Hyperacute Primary Intracerebral Haemorrhage) trial, we assessed baseline scans for hematoma location and presence of cerebral amyloid angiopathy (CAA) using computed tomography (CT, simplified Edinburgh criteria) and magnetic resonance imaging (MRI; Boston criteria) and categorized ICH as lobar CAA, lobar non-CAA, and nonlobar. The main outcomes were HE and favorable functional outcome. We constructed multivariate regression models and assessed treatment effects using interaction terms. RESULTS A total of 2,298 out of 2,325 participants were included with available CT (98.8%; median age = 71 years, interquartile range = 60-80 years; 1,014 female). Additional MRI was available in 219 patients (9.5%). Overall, 1,637 participants (71.2%) had nonlobar ICH; the remaining 661 participants (28.8%) had lobar ICH, of whom 202 patients had lobar CAA-ICH (8.8%, 173 participants according to Edinburgh and 29 participants according to Boston criteria) and 459 did not (lobar non-CAA, 20.0%). For HE, we found a significant interaction of lobar CAA ICH with time from onset to randomization (increasing risk with time, pinteraction < 0.001) and baseline ICH volume (constant risk regardless of volume, pinteraction < 0.001) but no association between type of ICH and risk of HE or favorable outcome. Tranexamic acid significantly reduced the risk of HE (adjusted odds ratio = 0.7, 95% confidence interval = 0.6-1.0, p = 0.020) without statistically significant interaction with type of ICH (pinteraction = 0.058). Tranexamic acid was not associated with favorable outcome. INTERPRETATION Risk of HE in patients with lobar CAA-ICH was not independently increased but seems to have different dynamics compared to other types of ICH. The time window for treatment of CAA-ICH to prevent HE may be longer. ANN NEUROL 2022;92:921-930.
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Affiliation(s)
- David J Seiffge
- Department of Neurology, Inselspital University Hospital and University of Bern, Bern, Switzerland
| | - Alexandros A Polymeris
- Department of Neurology and Stroke Center, University Hospital Basel and University of Basel, Basel, Switzerland
| | - Zhe Kang Law
- Stroke Trials Unit, University of Nottingham, Nottingham, UK.,Department of Medicine, National University of Malaysia, Bangi, Malaysia
| | - Kailash Krishnan
- Stroke Trials Unit, University of Nottingham, Nottingham, UK.,Stroke, Nottingham University Hospitals National Health Service Trust, Nottingham, UK
| | - Annaelle Zietz
- Department of Neurology and Stroke Center, University Hospital Basel and University of Basel, Basel, Switzerland
| | - Sebastian Thilemann
- Department of Neurology and Stroke Center, University Hospital Basel and University of Basel, Basel, Switzerland
| | - David Werring
- Stroke Research Centre, University College London Queen Square Institute of Neurology, London, UK
| | | | - Robert A Dineen
- Radiological Sciences, University of Nottingham, Nottingham, UK.,National Institute for Health Research Nottingham Biomedical Research Centre, Nottingham, UK
| | - Stefan T Engelter
- Department of Neurology and Stroke Center, University Hospital Basel and University of Basel, Basel, Switzerland.,Neurology and Neurorehabilitation, University Hospital for Geriatric Medicine Felix Platter, University of Basel, Basel, Switzerland
| | - Philip M Bath
- Stroke Trials Unit, University of Nottingham, Nottingham, UK.,Stroke, Nottingham University Hospitals National Health Service Trust, Nottingham, UK
| | - Nikola Sprigg
- Stroke Trials Unit, University of Nottingham, Nottingham, UK.,Stroke, Nottingham University Hospitals National Health Service Trust, Nottingham, UK
| | - Philippe Lyrer
- Department of Neurology and Stroke Center, University Hospital Basel and University of Basel, Basel, Switzerland
| | - Nils Peters
- Department of Neurology and Stroke Center, University Hospital Basel and University of Basel, Basel, Switzerland.,Neurology and Neurorehabilitation, University Hospital for Geriatric Medicine Felix Platter, University of Basel, Basel, Switzerland.,Stroke Center, Hirslanden Clinic, Zürich, Switzerland
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Blackwell JA, Silva JF, Louis EM, Savu A, Largent-Milnes TM, Brooks HL, Pires PW. Cerebral arteriolar and neurovascular dysfunction after chemically induced menopause in mice. Am J Physiol Heart Circ Physiol 2022; 323:H845-H860. [PMID: 36149767 PMCID: PMC9602916 DOI: 10.1152/ajpheart.00276.2022] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 09/20/2022] [Accepted: 09/20/2022] [Indexed: 12/14/2022]
Abstract
Cognitive decline is linked to decreased cerebral blood flow, particularly in women after menopause. Impaired cerebrovascular function precedes the onset of dementia, possibly because of reduced functional dilation in parenchymal arterioles. These vessels are bottlenecks of the cerebral microcirculation, and dysfunction can limit functional hyperemia in the brain. Large-conductance Ca2+-activated K+ channels (BKCa) are the final effectors of several pathways responsible for functional hyperemia, and their expression is modulated by estrogen. However, it remains unknown whether BKCa function is altered in cerebral parenchymal arterioles after menopause. Using a chemically induced model of menopause, the 4-vinylcyclohexene diepoxide (VCD) model, which depletes follicles while maintaining intact ovaries, we hypothesized that menopause would be associated with reduced functional vasodilatory responses in cerebral parenchymal arterioles of wild-type mice via reduced BKCa function. Using pressure myography of isolated parenchymal arterioles, we observed that menopause (Meno) induced a significant increase in spontaneous myogenic tone. Endothelial function, assessed as nitric oxide production and dilation after cholinergic stimulation or endothelium-dependent hyperpolarization pathways, was unaffected by Meno. BKCa function was significantly impaired in Meno compared with control, without changes in voltage-gated K+ channel activity. Cerebral functional hyperemia, measured by laser-speckle contrast imaging during whisker stimulation, was significantly blunted in Meno mice, without detectable changes in basal perfusion. However, behavioral testing identified no change in cognition. These findings suggest that menopause induces cerebral microvascular and neurovascular deficits.NEW & NOTEWORTHY Cerebral parenchymal arterioles from menopause mice showed increased myogenic tone. We identified an impairment in smooth muscle cell BKCa channel activity, without a reduction in endothelium-dependent dilation or nitric oxide production. Microvascular dysfunction was associated with a reduction in neurovascular responses after somatosensory stimulation. Despite the neurovascular impairment, cognitive abilities were maintained in menopausal mice.
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Affiliation(s)
- Jade A Blackwell
- Department of Physiology, University of Arizona, Tucson, Arizona
| | - Josiane F Silva
- Department of Physiology, University of Arizona, Tucson, Arizona
| | - Emma M Louis
- Department of Physiology, University of Arizona, Tucson, Arizona
| | - Andrea Savu
- Department of Physiology, University of Arizona, Tucson, Arizona
| | - Tally M Largent-Milnes
- Department of Pharmacology, University of Arizona, Tucson, Arizona
- Bio5 Institute, University of Arizona, Tucson, Arizona
| | - Heddwen L Brooks
- Department of Physiology, University of Arizona, Tucson, Arizona
- Bio5 Institute, University of Arizona, Tucson, Arizona
- Sarver Heart Center, University of Arizona, Tucson, Arizona
| | - Paulo W Pires
- Department of Physiology, University of Arizona, Tucson, Arizona
- Bio5 Institute, University of Arizona, Tucson, Arizona
- Sarver Heart Center, University of Arizona, Tucson, Arizona
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Xue Y, Georgakopoulou T, van der Wijk AE, Józsa TI, van Bavel E, Payne SJ. Quantification of hypoxic regions distant from occlusions in cerebral penetrating arteriole trees. PLoS Comput Biol 2022; 18:e1010166. [PMID: 35930591 PMCID: PMC9385041 DOI: 10.1371/journal.pcbi.1010166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 08/17/2022] [Accepted: 07/14/2022] [Indexed: 11/18/2022] Open
Abstract
The microvasculature plays a key role in oxygen transport in the mammalian brain. Despite the close coupling between cerebral vascular geometry and local oxygen demand, recent experiments have reported that microvascular occlusions can lead to unexpected distant tissue hypoxia and infarction. To better understand the spatial correlation between the hypoxic regions and the occlusion sites, we used both in vivo experiments and in silico simulations to investigate the effects of occlusions in cerebral penetrating arteriole trees on tissue hypoxia. In a rat model of microembolisation, 25 μm microspheres were injected through the carotid artery to occlude penetrating arterioles. In representative models of human cortical columns, the penetrating arterioles were occluded by simulating the transport of microspheres of the same size and the oxygen transport was simulated using a Green’s function method. The locations of microspheres and hypoxic regions were segmented, and two novel distance analyses were implemented to study their spatial correlation. The distant hypoxic regions were found to be present in both experiments and simulations, and mainly due to the hypoperfusion in the region downstream of the occlusion site. Furthermore, a reasonable agreement for the spatial correlation between hypoxic regions and occlusion sites is shown between experiments and simulations, which indicates the good applicability of in silico models in understanding the response of cerebral blood flow and oxygen transport to microemboli. The brain function depends on the continuous oxygen supply through the bloodstream inside the microvasculature. Occlusions in the microvascular network will disturb the oxygen delivery in the brain and result in hypoxic tissues that can lead to infarction and cognitive dysfunction. To aid in understanding the formation of hypoxic tissues caused by micro-occlusions in the penetrating arteriole trees, we use rodent experiments and simulations of human vascular networks to study the spatial correlations between the hypoxic regions and the occlusion locations. Our results suggest that hypoxic regions can form distally from the occlusion site, which agrees with the previous observations in the rat brain. These distant hypoxic regions are primarily due to the lack of blood flow in the brain tissues downstream of the occlusion. Moreover, a reasonable agreement of the spatial relationship is found between the experiments and the simulations, which indicates the applicability of in silico models to study the effects of microemboli on the brain tissue.
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Affiliation(s)
- Yidan Xue
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, United Kingdom
| | - Theodosia Georgakopoulou
- Department of Biomedical Engineering and Physics, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - Anne-Eva van der Wijk
- Department of Biomedical Engineering and Physics, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - Tamás I. Józsa
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, United Kingdom
| | - Ed van Bavel
- Department of Biomedical Engineering and Physics, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - Stephen J. Payne
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, United Kingdom
- Institute of Applied Mechanics, National Taiwan University, Taipei, Taiwan
- * E-mail:
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Singh AA, Kharwar A, Dandekar MP. A Review on Preclinical Models of Ischemic Stroke: Insights Into the Pathomechanisms and New Treatment Strategies. Curr Neuropharmacol 2022; 20:1667-1686. [PMID: 34493185 PMCID: PMC9881062 DOI: 10.2174/1570159x19666210907092928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 07/21/2021] [Accepted: 08/26/2021] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Stroke is a serious neurovascular problem and the leading cause of disability and death worldwide. The disrupted demand to supply ratio of blood and glucose during cerebral ischemia develops hypoxic shock, and subsequently necrotic neuronal death in the affected regions. Multiple causal factors like age, sex, race, genetics, diet, and lifestyle play an important role in the occurrence as well as progression of post-stroke deleterious events. These biological and environmental factors may be contributed to vasculature variable architecture and abnormal neuronal activity. Since recombinant tissue plasminogen activator is the only clinically effective clot bursting drug, there is a huge unmet medical need for newer therapies for the treatment of stroke. Innumerous therapeutic interventions have shown promise in the experimental models of stroke but failed to translate it into clinical counterparts. METHODS Original publications regarding pathophysiology, preclinical experimental models, new targets and therapies targeting ischemic stroke have been reviewed since the 1970s. RESULTS We highlighted the critical underlying pathophysiological mechanisms of cerebral stroke and preclinical stroke models. We discuss the strengths and caveats of widely used ischemic stroke models, and commented on the potential translational problems. We also describe the new emerging treatment strategies, including stem cell therapy, neurotrophic factors and gut microbiome-based therapy for the management of post-stroke consequences. CONCLUSION There are still many inter-linked pathophysiological alterations with regards to stroke, animal models need not necessarily mimic the same conditions of stroke pathology and newer targets and therapies are the need of the hour in stroke research.
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Affiliation(s)
- Aditya A. Singh
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, Balanagar, TS 500037, India
| | - Akash Kharwar
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, Balanagar, TS 500037, India
| | - Manoj P. Dandekar
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, Balanagar, TS 500037, India,Address correspondence to this author at the Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, Balanagar, TS 500037, India; Tel: +91-40-23074750; E-mail:
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Jeffrey DA, Fontaine JT, Dabertrand F. Ex vivo capillary-parenchymal arteriole approach to study brain pericyte physiology. NEUROPHOTONICS 2022; 9:031919. [PMID: 36278784 PMCID: PMC9225307 DOI: 10.1117/1.nph.9.3.031919] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 06/01/2022] [Indexed: 06/16/2023]
Abstract
Significance Vascular mural cells, defined as smooth muscle cells (SMCs) and pericytes, influence brain microcirculation, but how they contribute is not fully understood. Most approaches used to investigate pericyte and capillary interactions include ex vivo retinal/slice preparations or in vivo two-photon microscopy. However, neither method adequately captures mural cell behavior without interfering neuronal tissue. Thus, there is a need to isolate vessels with their respective mural cells to study functional and pathological changes. Aim The aim of our work was to implement an ex vivo method that recapitulates vessel dynamics in the brain. Approach Expanding upon our established ex vivo capillary-parenchymal arteriole (CaPA) preparation, we isolated and pressurized arteriole-capillary branches. Using Alexa Fluor™ 633 Hydrazide, we distinguished arterioles (containing elastin) versus capillaries (lacking elastin). In addition, our transgenic SMMHC-GCaMP6f mice allowed for us to visualize mural cell morphology andCa 2 + signals. Lastly, isolated microvasculature was cultured in DMEM media (up to 72 h), mounted, and pressurized using our CaPA preparation. Results U46619 induced a decrease in capillary lumen diameter using both a bath perfusion and local application. In addition, U46619 increasedCa 2 + signaling both globally and locally in contractile pericytes. In our SMMHC-GCaMP6f mice, we saw that thin strand pericytes had sparse processes while contractile pericytes had long, thick processes that wrapped around the lumen of the capillary. Fresh and cultured pericytes constricted in response to U46619 to the same level, and upstream arteriolar dilation induced by capillary stimulation with 10 mMK + remained unchanged by culture conditions adding another application of longer treatment to our approach. Conclusion Our ex vivo CaPA methodology facilitates observation of arteriolar SMC and pericyte dynamic changes in real-time without environmental factors. This method will help to better understand how mural cells differ based on microvasculature location.
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Affiliation(s)
- Danielle A. Jeffrey
- University of Colorado Anschutz Medical Campus, Department of Anesthesiology, Aurora, Colorado, United States
| | - Jackson T. Fontaine
- University of Colorado Anschutz Medical Campus, Department of Anesthesiology, Aurora, Colorado, United States
| | - Fabrice Dabertrand
- University of Colorado Anschutz Medical Campus, Department of Anesthesiology, Aurora, Colorado, United States
- University of Colorado Anschutz Medical Campus, Department of Pharmacology, Aurora, Colorado, United States
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Lansdell TA, Chambers LC, Dorrance AM. Endothelial Cells and the Cerebral Circulation. Compr Physiol 2022; 12:3449-3508. [PMID: 35766836 DOI: 10.1002/cphy.c210015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Endothelial cells form the innermost layer of all blood vessels and are the only vascular component that remains throughout all vascular segments. The cerebral vasculature has several unique properties not found in the peripheral circulation; this requires that the cerebral endothelium be considered as a unique entity. Cerebral endothelial cells perform several functions vital for brain health. The cerebral vasculature is responsible for protecting the brain from external threats carried in the blood. The endothelial cells are central to this requirement as they form the basis of the blood-brain barrier. The endothelium also regulates fibrinolysis, thrombosis, platelet activation, vascular permeability, metabolism, catabolism, inflammation, and white cell trafficking. Endothelial cells regulate the changes in vascular structure caused by angiogenesis and artery remodeling. Further, the endothelium contributes to vascular tone, allowing proper perfusion of the brain which has high energy demands and no energy stores. In this article, we discuss the basic anatomy and physiology of the cerebral endothelium. Where appropriate, we discuss the detrimental effects of high blood pressure on the cerebral endothelium and the contribution of cerebrovascular disease endothelial dysfunction and dementia. © 2022 American Physiological Society. Compr Physiol 12:3449-3508, 2022.
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Affiliation(s)
- Theresa A Lansdell
- Department of Pharmacology and Toxicology, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, 48824, USA
| | - Laura C Chambers
- Department of Pharmacology and Toxicology, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, 48824, USA
| | - Anne M Dorrance
- Department of Pharmacology and Toxicology, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, 48824, USA
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Choi WJ, Li Y, Wang RK, Kim JK. Automated counting of cerebral penetrating vessels using optical coherence tomography images of a mouse brain in vivo. Med Phys 2022; 49:5225-5235. [PMID: 35616390 DOI: 10.1002/mp.15775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 05/17/2022] [Accepted: 05/17/2022] [Indexed: 11/08/2022] Open
Abstract
RATIONALE AND OBJECTIVES Penetrating blood vessels emanating from cortical surface vasculature and lying deep in the cortex are essential vascular conduits for the shuttling of blood from superficial pial vessels to the capillary beds in parenchyma for the nourishment of neuronal brain tissues. Locating and counting the penetrating vessels is beneficial for the quantification of a course of ischemia in blood occlusive events such as stroke. This paper seeks to demonstrate and validate a method for automated penetrating vessel counting that uses optical coherence tomography (OCT). MATERIALS AND METHODS This paper proposes an OCT method that effectively identifies and grades the cortical penetrating vessels in perfusion. The key to the proposed method is the harnessing of vascular features found in the penetrating vessels, which are distinctive from those of other vessels. In particular, with an increase in the light attenuation and flow turbulence, the contrast in the mean projection of the OCT datacube decreases, whereas that in the maximum projection of the Doppler frequency variance datacube increases. By multiplying the inversion of the former with the latter, its binary thresholding is sufficient to highlight the penetrating vessels and allows for their counting over the projection image. RESULTS A computational method that leverages the decrease in mean OCT projection intensity and the increase in Doppler frequency variance at the penetrating vessel is developed. It successfully identifies and counts penetrating vessels with a high accuracy of over 87%. The penetrating vessel density is observed to be significantly reduced in the mouse model of focal ischemic stroke. CONCLUSION The OCT analysis is effective for counting penetrating blood vessels in mice brains and may be applied to the rapid diagnosis and treatment of stroke in stroke models of small animals. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Woo June Choi
- School of Electrical and Electronics Engineering, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul, 06974, Korea
| | - Yuandong Li
- Department of Bioengineering, University of Washington, Seattle, WA, 98195, USA
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, WA, 98195, USA
| | - Jun Ki Kim
- Department of Convergence Medicine, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Seoul, 05505, Korea.,Asan Institute for Life Science, Asan Medical Center, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Korea
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Kedarasetti RT, Drew PJ, Costanzo F. Arterial vasodilation drives convective fluid flow in the brain: a poroelastic model. Fluids Barriers CNS 2022; 19:34. [PMID: 35570287 PMCID: PMC9107702 DOI: 10.1186/s12987-022-00326-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 03/29/2022] [Indexed: 01/26/2023] Open
Abstract
The movement of fluid into, through, and out of the brain plays an important role in clearing metabolic waste. However, there is controversy regarding the mechanisms driving fluid movement in the fluid-filled paravascular spaces (PVS), and whether the movement of metabolic waste in the brain extracellular space (ECS) is primarily driven by diffusion or convection. The dilation of penetrating arterioles in the brain in response to increases in neural activity (neurovascular coupling) is an attractive candidate for driving fluid circulation, as it drives deformation of the brain tissue and of the PVS around arteries, resulting in fluid movement. We simulated the effects of vasodilation on fluid movement into and out of the brain ECS using a novel poroelastic model of brain tissue. We found that arteriolar dilations could drive convective flow through the ECS radially outward from the arteriole, and that this flow is sensitive to the dynamics of the dilation. Simulations of sleep-like conditions, with larger vasodilations and increased extracellular volume in the brain showed enhanced movement of fluid from the PVS into the ECS. Our simulations suggest that both sensory-evoked and sleep-related arteriolar dilations can drive convective flow of cerebrospinal fluid not just in the PVS, but also into the ECS through the PVS around arterioles.
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Affiliation(s)
- Ravi Teja Kedarasetti
- grid.29857.310000 0001 2097 4281Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA USA ,grid.29857.310000 0001 2097 4281Center for Neural Engineering, Pennsylvania State University, University Park, PA USA
| | - Patrick J. Drew
- grid.29857.310000 0001 2097 4281Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA USA ,grid.29857.310000 0001 2097 4281Center for Neural Engineering, Pennsylvania State University, University Park, PA USA ,grid.29857.310000 0001 2097 4281Department of Biomedical Engineering, Pennsylvania State University, University Park, PA USA ,grid.29857.310000 0001 2097 4281Department of Neurosurgery, Pennsylvania State University, University Park, PA USA
| | - Francesco Costanzo
- grid.29857.310000 0001 2097 4281Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA USA ,grid.29857.310000 0001 2097 4281Center for Neural Engineering, Pennsylvania State University, University Park, PA USA ,grid.29857.310000 0001 2097 4281Department of Biomedical Engineering, Pennsylvania State University, University Park, PA USA ,grid.29857.310000 0001 2097 4281Department of Mathematics, Pennsylvania State University, University Park, PA USA
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Brunner C, Macé E, Montaldo G, Urban A. Quantitative Hemodynamic Measurements in Cortical Vessels Using Functional Ultrasound Imaging. Front Neurosci 2022; 16:831650. [PMID: 35495056 PMCID: PMC9039668 DOI: 10.3389/fnins.2022.831650] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 02/23/2022] [Indexed: 01/17/2023] Open
Abstract
Red blood cell velocity (RBCv), cerebral blood flow (CBF), and volume (CBV) are three key parameters when describing brain hemodynamics. Functional ultrasound imaging is a Doppler-based method allowing for real-time measurement of relative CBV at high spatiotemporal resolution (100 × 110 × 300 μm3, up to 10 Hz) and large scale. Nevertheless, the measure of RBCv and CBF in small cortical vessels with functional ultrasound imaging remains challenging because of their orientation and size, which impairs the ability to perform precise measurements. We designed a directional flow filter to overpass these limitations allowing us to measure RBCv in single vessels using a standard functional ultrasound imaging system without contrast agents (e.g., microbubbles). This method allows to quickly extract the number of vessels in the cortex that was estimated to be approximately 650/cm3 in adult rats, with a 55–45% ratio for penetrating arterioles versus ascending venules. Then, we analyzed the changes in RBCv in these vessels during forepaw stimulation. We observed that ∼40 vessels located in the primary somatosensory forelimb cortex display a significant increase of the RBCv (median ΔRBCv ∼15%, maximal ΔRBCv ∼60%). As expected, we show that RBCv was higher for penetrating arterioles located in the center than in the periphery of the activated area. The proposed approach extends the capabilities of functional ultrasound imaging, which may contribute to a better understanding of the neurovascular coupling at the brain-wide scale.
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Affiliation(s)
- Clément Brunner
- Neuro-Electronics Research Flanders, Leuven, Belgium
- VIB, Leuven, Belgium
- Imec, Leuven, Belgium
- Department of Neuroscience, Faculty of Medicine, KU Leuven, Leuven, Belgium
| | - Emilie Macé
- Brain-Wide Circuits for Behavior Research Group, Max Planck Institute of Neurobiology, Martinsried, Germany
| | - Gabriel Montaldo
- Neuro-Electronics Research Flanders, Leuven, Belgium
- VIB, Leuven, Belgium
- Imec, Leuven, Belgium
- Department of Neuroscience, Faculty of Medicine, KU Leuven, Leuven, Belgium
| | - Alan Urban
- Neuro-Electronics Research Flanders, Leuven, Belgium
- VIB, Leuven, Belgium
- Imec, Leuven, Belgium
- Department of Neuroscience, Faculty of Medicine, KU Leuven, Leuven, Belgium
- *Correspondence: Alan Urban,
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Fan JL, Brassard P, Rickards CA, Nogueira RC, Nasr N, McBryde FD, Fisher JP, Tzeng YC. Integrative cerebral blood flow regulation in ischemic stroke. J Cereb Blood Flow Metab 2022; 42:387-403. [PMID: 34259070 PMCID: PMC8985438 DOI: 10.1177/0271678x211032029] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Optimizing cerebral perfusion is key to rescuing salvageable ischemic brain tissue. Despite being an important determinant of cerebral perfusion, there are no effective guidelines for blood pressure (BP) management in acute stroke. The control of cerebral blood flow (CBF) involves a myriad of complex pathways which are largely unaccounted for in stroke management. Due to its unique anatomy and physiology, the cerebrovascular circulation is often treated as a stand-alone system rather than an integral component of the cardiovascular system. In order to optimize the strategies for BP management in acute ischemic stroke, a critical reappraisal of the mechanisms involved in CBF control is needed. In this review, we highlight the important role of collateral circulation and re-examine the pathophysiology of CBF control, namely the determinants of cerebral perfusion pressure gradient and resistance, in the context of stroke. Finally, we summarize the state of our knowledge regarding cardiovascular and cerebrovascular interaction and explore some potential avenues for future research in ischemic stroke.
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Affiliation(s)
- Jui-Lin Fan
- Manaaki Mānawa - The Centre for Heart Research, Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Patrice Brassard
- Department of Kinesiology, Faculty of Medicine, Université Laval, Québec City, Canada.,Research Center of the Institut universitaire de cardiologie et de pneumologie de Québec, Québec City, Canada
| | - Caroline A Rickards
- Department of Physiology & Anatomy, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Ricardo C Nogueira
- Neurology Department, School of Medicine, Hospital das Clinicas, University of São Paulo, São Paulo, Brazil.,Neurology Department, Hospital Nove de Julho, São Paulo, Brazil
| | - Nathalie Nasr
- Department of Neurology, Toulouse University Hospital, NSERM UMR 1297, Toulouse, France
| | - Fiona D McBryde
- Manaaki Mānawa - The Centre for Heart Research, Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - James P Fisher
- Manaaki Mānawa - The Centre for Heart Research, Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Yu-Chieh Tzeng
- Wellington Medical Technology Group, Department of Surgery and Anaesthesia, University of Otago, Wellington, New Zealand.,Department of Surgery & Anaesthesia, Centre for Translational Physiology, University of Otago, Wellington, New Zealand
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Optical Modalities for Research, Diagnosis, and Treatment of Stroke and the Consequent Brain Injuries. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12041891] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Stroke is the second most common cause of death and third most common cause of disability worldwide. Therefore, it is an important disease from a medical standpoint. For this reason, various studies have developed diagnostic and therapeutic techniques for stroke. Among them, developments and applications of optical modalities are being extensively studied. In this article, we explored three important optical modalities for research, diagnostic, and therapeutics for stroke and the brain injuries related to it: (1) photochemical thrombosis to investigate stroke animal models; (2) optical imaging techniques for in vivo preclinical studies on stroke; and (3) optical neurostimulation based therapy for stroke. We believe that an exploration and an analysis of previous studies will help us proceed from research to clinical applications of optical modalities for research, diagnosis, and treatment of stroke.
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41
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Hartmann DA, Coelho-Santos V, Shih AY. Pericyte Control of Blood Flow Across Microvascular Zones in the Central Nervous System. Annu Rev Physiol 2022; 84:331-354. [PMID: 34672718 PMCID: PMC10480047 DOI: 10.1146/annurev-physiol-061121-040127] [Citation(s) in RCA: 70] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The vast majority of the brain's vascular length is composed of capillaries, where our understanding of blood flow control remains incomplete. This review synthesizes current knowledge on the control of blood flow across microvascular zones by addressing issues with nomenclature and drawing on new developments from in vivo optical imaging and single-cell transcriptomics. Recent studies have highlighted important distinctions in mural cell morphology, gene expression, and contractile dynamics, which can explain observed differences in response to vasoactive mediators between arteriole, transitional, and capillary zones. Smooth muscle cells of arterioles and ensheathing pericytes of the arteriole-capillary transitional zone control large-scale, rapid changes in blood flow. In contrast, capillary pericytes downstream of the transitional zone act on slower and smaller scales and are involved in establishing resting capillary tone and flow heterogeneity. Many unresolved issues remain, including the vasoactive mediators that activate the different pericyte types in vivo, the role of pericyte-endothelial communication in conducting signals from capillaries to arterioles, and how neurological disease affects these mechanisms.
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Affiliation(s)
- David A Hartmann
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, California, USA
| | - Vanessa Coelho-Santos
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, Washington, USA;
- Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | - Andy Y Shih
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, Washington, USA;
- Department of Pediatrics, University of Washington, Seattle, Washington, USA
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
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42
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Dholakia KY, Guevara-Torres A, Feng G, Power D, Schallek J. In Vivo Capillary Structure and Blood Cell Flux in the Normal and Diabetic Mouse Eye. Invest Ophthalmol Vis Sci 2022; 63:18. [PMID: 35138346 PMCID: PMC8842443 DOI: 10.1167/iovs.63.2.18] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Purpose To characterize the early structural and functional changes in the retinal microvasculature in response to hyperglycemia in the Ins2Akita mouse. Methods A custom phase-contrast adaptive optics scanning light ophthalmoscope was used to image retinal capillaries of 9 Ins2Akita positive (hyperglycemic) and 9 Ins2Akita negative (euglycemic) mice from postnatal weeks 5 to 18. A 15 kHz point scan was used to image capillaries and measure red blood cell flux at biweekly intervals; measurements were performed manually. Retinal thickness and fundus photos were captured monthly using a commercial scanning laser ophthalmoscope/optical coherence tomography. Retinal thickness was calculated using a custom algorithm. Blood glucose and weight were tracked throughout the duration of the study. Results Elevated blood glucose (>250 mg/dL) was observed at 4 to 5 weeks of age in Ins2Akita mice and remained elevated throughout the study, whereas euglycemic littermates maintained normal glucose levels. There was no significant difference in red blood cell flux, capillary anatomy, lumen diameter, or occurrence of stalled capillaries between hyperglycemic and euglycemic mice between postnatal weeks 5 and 18. Hyperglycemic mice had a thinner retina than euglycemic littermates (p < 0.001), but retinal thickness did not change with duration of hyperglycemia despite glucose levels that were more than twice times normal. Conclusions In early stages of hyperglycemia, retinal microvasculature structure (lumen diameter, capillary anatomy) and function (red blood cell flux, capillary perfusion) were not impaired despite 3 months of chronically elevated blood glucose. These findings suggest that hyperglycemia alone for 3 months does not alter capillary structure or function in profoundly hyperglycemic mice.
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Affiliation(s)
- Kosha Y Dholakia
- Department of Biomedical Engineering, University of Rochester, Rochester, New York, United States.,Center for Visual Science, University of Rochester, Rochester, New York, United States
| | - Andres Guevara-Torres
- Center for Visual Science, University of Rochester, Rochester, New York, United States.,The Institute of Optics, University of Rochester, Rochester, New York, United States
| | - Guanping Feng
- Department of Biomedical Engineering, University of Rochester, Rochester, New York, United States.,Center for Visual Science, University of Rochester, Rochester, New York, United States
| | - Derek Power
- Center for Visual Science, University of Rochester, Rochester, New York, United States.,Flaum Eye Institute, University of Rochester, Rochester, New York, United States
| | - Jesse Schallek
- Center for Visual Science, University of Rochester, Rochester, New York, United States.,Flaum Eye Institute, University of Rochester, Rochester, New York, United States.,Department of Neuroscience, University of Rochester, Rochester, New York, United States
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43
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De Silva TM, Sobey CG. Cerebral Vascular Biology in Health and Disease. Stroke 2022. [DOI: 10.1016/b978-0-323-69424-7.00001-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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44
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Shao X, Guo F, Shou Q, Wang K, Jann K, Yan L, Toga AW, Zhang P, Wang DJJ. Laminar perfusion imaging with zoomed arterial spin labeling at 7 Tesla. Neuroimage 2021; 245:118724. [PMID: 34780918 PMCID: PMC8727512 DOI: 10.1016/j.neuroimage.2021.118724] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 10/23/2021] [Accepted: 11/11/2021] [Indexed: 10/19/2022] Open
Abstract
Laminar fMRI based on BOLD and CBV contrast at ultrahigh magnetic fields has been applied for studying the dynamics of mesoscopic brain networks. However, the quantitative interpretations of BOLD/CBV fMRI results are confounded by different baseline physiology across cortical layers. Here we introduce a novel 3D zoomed pseudo-continuous arterial spin labeling (pCASL) technique at 7T that offers the capability for quantitative measurements of laminar cerebral blood flow (CBF) both at rest and during task activation with high spatial specificity and sensitivity. We found arterial transit time in superficial layers is ∼100 ms shorter than in middle/deep layers revealing the time course of labeled blood flowing from pial arteries to downstream microvasculature. Resting state CBF peaked in the middle layers which is highly consistent with microvascular density measured from human cortex specimens. Finger tapping induced a robust two-peak laminar profile of CBF increases in the superficial (somatosensory and premotor input) and deep (spinal output) layers of M1, while finger brushing task induced a weaker CBF increase in superficial layers (somatosensory input). This observation is highly consistent with reported laminar profiles of CBV activation on M1. We further demonstrated that visuospatial attention induced a predominant CBF increase in deep layers and a smaller CBF increase on top of the lower baseline CBF in superficial layers of V1 (feedback cortical input), while stimulus driven activity peaked in the middle layers (feedforward thalamic input). With the capability for quantitative CBF measurements both at baseline and during task activation, high-resolution ASL perfusion fMRI at 7T provides an important tool for in vivo assessment of neurovascular function and metabolic activities of neural circuits across cortical layers.
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Affiliation(s)
- Xingfeng Shao
- Laboratory of FMRI Technology (LOFT), USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, 2025 Zonal Ave, Los Angeles, CA 90033, USA
| | - Fanhua Guo
- State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Qinyang Shou
- Laboratory of FMRI Technology (LOFT), USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, 2025 Zonal Ave, Los Angeles, CA 90033, USA
| | - Kai Wang
- Laboratory of FMRI Technology (LOFT), USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, 2025 Zonal Ave, Los Angeles, CA 90033, USA
| | - Kay Jann
- Laboratory of FMRI Technology (LOFT), USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, 2025 Zonal Ave, Los Angeles, CA 90033, USA; Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Lirong Yan
- Laboratory of FMRI Technology (LOFT), USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, 2025 Zonal Ave, Los Angeles, CA 90033, USA; Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Arthur W Toga
- Laboratory of Neuroimaging, USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Peng Zhang
- State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Danny J J Wang
- Laboratory of FMRI Technology (LOFT), USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, 2025 Zonal Ave, Los Angeles, CA 90033, USA; Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.
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45
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de Bortoli T, Boehm-Sturm P, Koch SP, Nieminen-Kelhä M, Wessels L, Mueller S, Ielacqua GD, Klohs J, Vajkoczy P, Hecht N. Three-Dimensional Iron Oxide Nanoparticle-Based Contrast-Enhanced Magnetic Resonance Imaging for Characterization of Cerebral Arteriogenesis in the Mouse Neocortex. Front Neurosci 2021; 15:756577. [PMID: 34899163 PMCID: PMC8662986 DOI: 10.3389/fnins.2021.756577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 11/02/2021] [Indexed: 11/13/2022] Open
Abstract
Purpose: Subsurface blood vessels in the cerebral cortex have been identified as a bottleneck in cerebral perfusion with the potential for collateral remodeling. However, valid techniques for non-invasive, longitudinal characterization of neocortical microvessels are still lacking. In this study, we validated contrast-enhanced magnetic resonance imaging (CE-MRI) for in vivo characterization of vascular changes in a model of spontaneous collateral outgrowth following chronic cerebral hypoperfusion. Methods: C57BL/6J mice were randomly assigned to unilateral internal carotid artery occlusion or sham surgery and after 21 days, CE-MRI based on T2*-weighted imaging was performed using ultra-small superparamagnetic iron oxide nanoparticles to obtain subtraction angiographies and steady-state cerebral blood volume (ss-CBV) maps. First pass dynamic susceptibility contrast MRI (DSC-MRI) was performed for internal validation of ss-CBV. Further validation at the histological level was provided by ex vivo serial two-photon tomography (STP). Results: Qualitatively, an increase in vessel density was observed on CE-MRI subtraction angiographies following occlusion; however, a quantitative vessel tracing analysis was prone to errors in our model. Measurements of ss-CBV reliably identified an increase in cortical vasculature, validated by DSC-MRI and STP. Conclusion: Iron oxide nanoparticle-based ss-CBV serves as a robust, non-invasive imaging surrogate marker for neocortical vessels, with the potential to reduce and refine preclinical models targeting the development and outgrowth of cerebral collateralization.
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Affiliation(s)
- Till de Bortoli
- Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany.,Center for Stroke Research Berlin (CSB), Berlin, Germany
| | - Philipp Boehm-Sturm
- Center for Stroke Research Berlin (CSB), Berlin, Germany.,Department of Experimental Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany.,NeuroCure Cluster of Excellence and Charité Core Facility 7T Experimental MRIs, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Stefan P Koch
- Center for Stroke Research Berlin (CSB), Berlin, Germany.,Department of Experimental Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany.,NeuroCure Cluster of Excellence and Charité Core Facility 7T Experimental MRIs, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Melina Nieminen-Kelhä
- Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany.,Center for Stroke Research Berlin (CSB), Berlin, Germany
| | - Lars Wessels
- Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany.,Center for Stroke Research Berlin (CSB), Berlin, Germany
| | - Susanne Mueller
- Center for Stroke Research Berlin (CSB), Berlin, Germany.,Department of Experimental Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany.,NeuroCure Cluster of Excellence and Charité Core Facility 7T Experimental MRIs, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Giovanna D Ielacqua
- Institute for Biomedical Engineering, University of Zurich and ETH Zürich, Zurich, Switzerland
| | - Jan Klohs
- Institute for Biomedical Engineering, University of Zurich and ETH Zürich, Zurich, Switzerland
| | - Peter Vajkoczy
- Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany.,Center for Stroke Research Berlin (CSB), Berlin, Germany
| | - Nils Hecht
- Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany.,Center for Stroke Research Berlin (CSB), Berlin, Germany
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46
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Qohar UNA, Zanna Munthe-Kaas A, Nordbotten JM, Hanson EA. A nonlinear multi-scale model for blood circulation in a realistic vascular system. ROYAL SOCIETY OPEN SCIENCE 2021; 8:201949. [PMID: 34966547 PMCID: PMC8633777 DOI: 10.1098/rsos.201949] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 10/28/2021] [Indexed: 06/14/2023]
Abstract
In the last decade, numerical models have become an increasingly important tool in biological and medical science. Numerical simulations contribute to a deeper understanding of physiology and are a powerful tool for better diagnostics and treatment. In this paper, a nonlinear multi-scale model framework is developed for blood flow distribution in the full vascular system of an organ. We couple a quasi one-dimensional vascular graph model to represent blood flow in larger vessels and a porous media model to describe flow in smaller vessels and capillary bed. The vascular model is based on Poiseuille's Law, with pressure correction by elasticity and pressure drop estimation at vessels' junctions. The porous capillary bed is modelled as a two-compartment domain (artery and venous) using Darcy's Law. The fluid exchange between the artery and venous capillary bed compartments is defined as blood perfusion. The numerical experiments show that the proposed model for blood circulation: (i) is closely dependent on the structure and parameters of both the larger vessels and of the capillary bed, and (ii) provides a realistic blood circulation in the organ. The advantage of the proposed model is that it is complex enough to reliably capture the main underlying physiological function, yet highly flexible as it offers the possibility of incorporating various local effects. Furthermore, the numerical implementation of the model is straightforward and allows for simulations on a regular desktop computer.
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Affiliation(s)
- Ulin Nuha A. Qohar
- Department of Mathematics, University of Bergen, Allegaten 41, Bergen 5008, Norway
| | | | | | - Erik Andreas Hanson
- Department of Mathematics, University of Bergen, Allegaten 41, Bergen 5008, Norway
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47
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Georgakopoulou T, van der Wijk AE, Bakker ENTP, vanBavel E. Quantitative 3D analysis of tissue damage in a rat model of microembolization. J Biomech 2021; 128:110723. [PMID: 34509910 DOI: 10.1016/j.jbiomech.2021.110723] [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: 04/12/2021] [Revised: 07/16/2021] [Accepted: 08/25/2021] [Indexed: 11/26/2022]
Abstract
There is a discrepancy between successful recanalization and good clinical outcome after endovascular treatment (EVT) in acute ischemic stroke patients. During removal of a thrombus, a shower of microemboli may release and lodge to the distal circulation. The objective of this study was to determine the extent of damage on brain tissue caused by microemboli. In a rat model of microembolization, a mixture of microsphere (MS) sizes (15, 25 and 50 µm diameter) was injected via the left internal carotid artery. A 3D image of the left hemisphere was reconstructed and a point-pattern spatial analysis was applied based on G- and K-functions to unravel the spatial correlation between MS and the induced hypoxia or infarction. We show a spatial correlation between MS and hypoxia or infarction spreading up to a distance of 1000-1500 µm. These results imply that microemboli, which individually may not always be harmful, can interact and result in local areas of hypoxia or even infarction when lodged in large numbers.
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Affiliation(s)
- Theodosia Georgakopoulou
- Amsterdam University Medical Centers, University of Amsterdam, Biomedical Engineering and Physics, Amsterdam Cardiovascular Sciences, Meibergdreef 9, Amsterdam, The Netherlands
| | - Anne-Eva van der Wijk
- Amsterdam University Medical Centers, University of Amsterdam, Biomedical Engineering and Physics, Amsterdam Cardiovascular Sciences, Meibergdreef 9, Amsterdam, The Netherlands
| | - Erik N T P Bakker
- Amsterdam University Medical Centers, University of Amsterdam, Biomedical Engineering and Physics, Amsterdam Cardiovascular Sciences, Meibergdreef 9, Amsterdam, The Netherlands
| | - Ed vanBavel
- Amsterdam University Medical Centers, University of Amsterdam, Biomedical Engineering and Physics, Amsterdam Cardiovascular Sciences, Meibergdreef 9, Amsterdam, The Netherlands.
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48
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Chen C, She Z, Tang P, Qin Z, He J, Qu JY. Study of neurovascular coupling by using mesoscopic and microscopic imaging. iScience 2021; 24:103176. [PMID: 34693226 PMCID: PMC8511898 DOI: 10.1016/j.isci.2021.103176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 07/02/2021] [Accepted: 09/22/2021] [Indexed: 12/05/2022] Open
Abstract
Neuronal activation is often accompanied by the regulation of cerebral hemodynamics via a process known as neurovascular coupling (NVC) which is essential for proper brain function and has been observed to be disrupted in a variety of neuropathologies. A comprehensive understanding of NVC requires imaging capabilities with high spatiotemporal resolution and a field-of-view that spans different orders of magnitude. Here, we present an approach for concurrent multi-contrast mesoscopic and two-photon microscopic imaging of neurovascular dynamics in the cortices of live mice. We investigated the spatiotemporal correlation between sensory-evoked neuronal and vascular responses in the auditory cortices of living mice using four imaging modalities. Our findings unravel drastic differences in the NVC at the regional and microvascular levels and the distinctive effects of different brain states on NVC. We further investigated the brain-state-dependent changes of NVC in large cortical networks and revealed that anesthesia and sedation caused spatiotemporal disruption of NVC. Concurrent mesoscopic and microscopic imaging of neurovascular dynamics Spatiotemporal characteristics of neurovascular responses across multiple scales Distinct effects of anesthesia and sedation on neurovascular coupling Cortex-wide correlation of neuronal activity and cerebral hemodynamics
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Affiliation(s)
- Congping Chen
- Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China.,State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China.,Center of Systems Biology and Human Health, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China
| | - Zhentao She
- Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China.,State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China.,Center of Systems Biology and Human Health, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China
| | - Peng Tang
- Department of Neuroscience (NS), City University of Hong Kong, Hong Kong, P.R. China.,Centre for Regenerative Medicine and Health, Hong Kong Institute of Science & Innovation, Chinese Academy of Sciences, Hong Kong SAR, P.R. China
| | - Zhongya Qin
- Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China.,State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China.,Center of Systems Biology and Human Health, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China
| | - Jufang He
- Department of Neuroscience (NS), City University of Hong Kong, Hong Kong, P.R. China
| | - Jianan Y Qu
- Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China.,State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China.,Center of Systems Biology and Human Health, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China
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49
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Xue Y, El-Bouri WK, Józsa TI, Payne SJ. Modelling the effects of cerebral microthrombi on tissue oxygenation and cell death. J Biomech 2021; 127:110705. [PMID: 34464872 DOI: 10.1016/j.jbiomech.2021.110705] [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: 01/25/2021] [Revised: 07/19/2021] [Accepted: 08/16/2021] [Indexed: 11/29/2022]
Abstract
Thrombectomy, the mechanical removal of a clot, is the most common way to treat ischaemic stroke with large vessel occlusions. However, perfusion cannot always be restored after such an intervention. It has been hypothesised that the absence of reperfusion is at least partially due to the clot fragments that block the downstream vessels. In this paper, we present a new way of quantifying the effects of cerebral microthrombi on oxygen transport to tissue in terms of hypoxia and ischaemia. The oxygen transport was simulated with the Green's function method on physiologically representative microvascular cubes, which was found independent of both microvascular geometry and length scale. The microthrombi occlusions were then simulated in the microvasculature, which were extravasated over time with a new thrombus extravasation model. The tissue hypoxic fraction was fitted as a sigmoidal function of vessel blockage fraction, which was then taken to be a function of time after the formation of microthrombi occlusions. A novel hypoxia-based 3-state cell death model was finally proposed to simulate the hypoxic tissue damage over time. Using the cell death model, the impact of a certain degree of microthrombi occlusions on tissue viability and microinfarct volume can be predicted over time. Quantifying the impact of microthrombi on oxygen transport and tissue death will play an important role in full brain models of ischaemic stroke and thrombectomy.
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Affiliation(s)
- Yidan Xue
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, UK.
| | - Wahbi K El-Bouri
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, UK; Liverpool Centre for Cardiovascular Science, Department of Cardiovascular and Metabolic Medicine, University of Liverpool, Liverpool, UK
| | - Tamás I Józsa
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, UK
| | - Stephen J Payne
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, UK
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50
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Contribution of animal models toward understanding resting state functional connectivity. Neuroimage 2021; 245:118630. [PMID: 34644593 DOI: 10.1016/j.neuroimage.2021.118630] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 08/06/2021] [Accepted: 09/29/2021] [Indexed: 12/27/2022] Open
Abstract
Functional connectivity, which reflects the spatial and temporal organization of intrinsic activity throughout the brain, is one of the most studied measures in human neuroimaging research. The noninvasive acquisition of resting state functional magnetic resonance imaging (rs-fMRI) allows the characterization of features designated as functional networks, functional connectivity gradients, and time-varying activity patterns that provide insight into the intrinsic functional organization of the brain and potential alterations related to brain dysfunction. Functional connectivity, hence, captures dimensions of the brain's activity that have enormous potential for both clinical and preclinical research. However, the mechanisms underlying functional connectivity have yet to be fully characterized, hindering interpretation of rs-fMRI studies. As in other branches of neuroscience, the identification of the neurophysiological processes that contribute to functional connectivity largely depends on research conducted on laboratory animals, which provide a platform where specific, multi-dimensional investigations that involve invasive measurements can be carried out. These highly controlled experiments facilitate the interpretation of the temporal correlations observed across the brain. Indeed, information obtained from animal experimentation to date is the basis for our current understanding of the underlying basis for functional brain connectivity. This review presents a compendium of some of the most critical advances in the field based on the efforts made by the animal neuroimaging community.
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