1
|
Bergs J, Morr AS, Silva RV, Infante-Duarte C, Sack I. The Networking Brain: How Extracellular Matrix, Cellular Networks, and Vasculature Shape the In Vivo Mechanical Properties of the Brain. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2402338. [PMID: 38874205 DOI: 10.1002/advs.202402338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 05/22/2024] [Indexed: 06/15/2024]
Abstract
Mechanically, the brain is characterized by both solid and fluid properties. The resulting unique material behavior fosters proliferation, differentiation, and repair of cellular and vascular networks, and optimally protects them from damaging shear forces. Magnetic resonance elastography (MRE) is a noninvasive imaging technique that maps the mechanical properties of the brain in vivo. MRE studies have shown that abnormal processes such as neuronal degeneration, demyelination, inflammation, and vascular leakage lead to tissue softening. In contrast, neuronal proliferation, cellular network formation, and higher vascular pressure result in brain stiffening. In addition, brain viscosity has been reported to change with normal blood perfusion variability and brain maturation as well as disease conditions such as tumor invasion. In this article, the contributions of the neuronal, glial, extracellular, and vascular networks are discussed to the coarse-grained parameters determined by MRE. This reductionist multi-network model of brain mechanics helps to explain many MRE observations in terms of microanatomical changes and suggests that cerebral viscoelasticity is a suitable imaging marker for brain disease.
Collapse
Affiliation(s)
- Judith Bergs
- Department of Radiology, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Anna S Morr
- Department of Radiology, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Rafaela V Silva
- Experimental and Clinical Research Center, a cooperation between the Max Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité - Universitätsmedizin Berlin, Lindenberger Weg 80, 13125, Berlin, Germany
- Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, ECRC Experimental and Clinical Research Center, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Straße 10, 13125, Berlin, Germany
| | - Carmen Infante-Duarte
- Experimental and Clinical Research Center, a cooperation between the Max Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité - Universitätsmedizin Berlin, Lindenberger Weg 80, 13125, Berlin, Germany
- Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, ECRC Experimental and Clinical Research Center, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Straße 10, 13125, Berlin, Germany
| | - Ingolf Sack
- Department of Radiology, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
| |
Collapse
|
2
|
Barrasa-Ramos S, Dessalles CA, Hautefeuille M, Barakat AI. Mechanical regulation of the early stages of angiogenesis. J R Soc Interface 2022; 19:20220360. [PMID: 36475392 PMCID: PMC9727679 DOI: 10.1098/rsif.2022.0360] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Favouring or thwarting the development of a vascular network is essential in fields as diverse as oncology, cardiovascular disease or tissue engineering. As a result, understanding and controlling angiogenesis has become a major scientific challenge. Mechanical factors play a fundamental role in angiogenesis and can potentially be exploited for optimizing the architecture of the resulting vascular network. Largely focusing on in vitro systems but also supported by some in vivo evidence, the aim of this Highlight Review is dual. First, we describe the current knowledge with particular focus on the effects of fluid and solid mechanical stimuli on the early stages of the angiogenic process, most notably the destabilization of existing vessels and the initiation and elongation of new vessels. Second, we explore inherent difficulties in the field and propose future perspectives on the use of in vitro and physics-based modelling to overcome these difficulties.
Collapse
Affiliation(s)
- Sara Barrasa-Ramos
- LadHyX, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, Palaiseau, France
| | - Claire A. Dessalles
- LadHyX, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, Palaiseau, France
| | - Mathieu Hautefeuille
- Laboratoire de Biologie du Développement (UMR7622), Institut de Biologie Paris Seine, Sorbonne Université, Paris, France,Facultad de Ciencias, Universidad Nacional Autónoma de México, CDMX, Mexico
| | - Abdul I. Barakat
- LadHyX, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, Palaiseau, France
| |
Collapse
|
3
|
Zhang Z, Hwang M, Kilbaugh TJ, Sridharan A, Katz J. Cerebral microcirculation mapped by echo particle tracking velocimetry quantifies the intracranial pressure and detects ischemia. Nat Commun 2022; 13:666. [PMID: 35115552 PMCID: PMC8814032 DOI: 10.1038/s41467-022-28298-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 01/14/2022] [Indexed: 12/26/2022] Open
Abstract
Affecting 1.1‰ of infants, hydrocephalus involves abnormal accumulation of cerebrospinal fluid, resulting in elevated intracranial pressure (ICP). It is the leading cause for brain surgery in newborns, often causing long-term neurologic disabilities or even death. Since conventional invasive ICP monitoring is risky, early neurosurgical interventions could benefit from noninvasive techniques. Here we use clinical contrast-enhanced ultrasound (CEUS) imaging and intravascular microbubble tracking algorithms to map the cerebral blood flow in hydrocephalic pediatric porcine models. Regional microvascular perfusions are quantified by the cerebral microcirculation (CMC) parameter, which accounts for the concentration of micro-vessels and flow velocity in them. Combining CMC with hemodynamic parameters yields functional relationships between cortical micro-perfusion and ICP, with correlation coefficients exceeding 0.85. For cerebral ischemia cases, the nondimensionalized cortical micro-perfusion decreases by an order of magnitude when ICP exceeds 50% of the MAP. These findings suggest that CEUS-based CMC measurement is a plausible noninvasive method for assessing the ICP and detecting ischemia.
Collapse
Affiliation(s)
- Zeng Zhang
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Misun Hwang
- Department of Radiology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Todd J Kilbaugh
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Anush Sridharan
- Department of Radiology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Joseph Katz
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, USA.
| |
Collapse
|
4
|
Herthum H, Dempsey SCH, Samani A, Schrank F, Shahryari M, Warmuth C, Tzschätzsch H, Braun J, Sack I. Superviscous properties of the in vivo brain at large scales. Acta Biomater 2021; 121:393-404. [PMID: 33326885 DOI: 10.1016/j.actbio.2020.12.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 12/08/2020] [Accepted: 12/10/2020] [Indexed: 12/28/2022]
Abstract
There is growing awareness that brain mechanical properties are important for neural development and health. However, published values of brain stiffness differ by orders of magnitude between static measurements and in vivo magnetic resonance elastography (MRE), which covers a dynamic range over several frequency decades. We here show that there is no fundamental disparity between static mechanical tests and in vivo MRE when considering large-scale properties, which encompass the entire brain including fluid filled compartments. Using gradient echo real-time MRE, we investigated the viscoelastic dispersion of the human brain in, so far, unexplored dynamic ranges from intrinsic brain pulsations at 1 Hz to ultralow-frequency vibrations at 5, 6.25, 7.8 and 10 Hz to the normal frequency range of MRE of 40 Hz. Surprisingly, we observed variations in brain stiffness over more than two orders of magnitude, suggesting that the in vivo human brain is superviscous on large scales with very low shear modulus of 42±13 Pa and relatively high viscosity of 6.6±0.3 Pa∙s according to the two-parameter solid model. Our data shed light on the crucial role of fluid compartments including blood vessels and cerebrospinal fluid (CSF) for whole brain properties and provide, for the first time, an explanation for the variability of the mechanical brain responses to manual palpation, local indentation, and high-dynamic tissue stimulation as used in elastography.
Collapse
|
5
|
Driver ID, Traat M, Fasano F, Wise RG. Most Small Cerebral Cortical Veins Demonstrate Significant Flow Pulsatility: A Human Phase Contrast MRI Study at 7T. Front Neurosci 2020; 14:415. [PMID: 32431591 PMCID: PMC7214844 DOI: 10.3389/fnins.2020.00415] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 04/06/2020] [Indexed: 12/22/2022] Open
Abstract
Phase contrast MRI (pcMRI) has been used to investigate flow pulsatility in cerebral arteries, larger cerebral veins, and the cerebrospinal fluid (CSF). Such measurements of intracranial pulsatility and compliance are beginning to inform understanding of the pathophysiology of conditions including normal pressure hydrocephalus, multiple sclerosis, and dementias. We demonstrate the presence of flow pulsatility in small cerebral cortical veins, for the first time using pcMRI at 7 T, with the aim of improving our understanding of the hemodynamics of this little-studied vascular compartment. A method for establishing where venous flow is pulsatile is introduced, revealing significant pulsatility in 116 out of 146 veins, across eight healthy participants, assessed in parietal and frontal regions. Distributions of pulsatility index (PI) and pulse waveform delay were characterized, indicating a small, but statistically significant (p < 0.05), delay of 59 ± 41 ms in cortical veins with respect to the superior sagittal sinus, but no differences between veins draining different arterial supply territories. Measurements of pulsatility in smaller cortical veins, a hitherto unstudied compartment closer to the capillary bed, could lead to a better understanding of intracranial compliance and cerebrovascular (patho)physiology.
Collapse
Affiliation(s)
- Ian D Driver
- Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, Cardiff, United Kingdom
| | - Maarika Traat
- Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, Cardiff, United Kingdom.,Institute of Psychology, University of Tartu, Tartu, Estonia
| | | | - Richard G Wise
- Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, Cardiff, United Kingdom.,Department of Neuroscience, Imaging and Clinical Sciences, "G. D'Annunzio University" of Chieti-Pescara, Chieti, Italy.,Institute for Advanced Biomedical Technologies, "G. D'Annunzio University" of Chieti-Pescara, Chieti, Italy
| |
Collapse
|
6
|
Schrank F, Warmuth C, Tzschätzsch H, Kreft B, Hirsch S, Braun J, Elgeti T, Sack I. Cardiac-gated steady-state multifrequency magnetic resonance elastography of the brain: Effect of cerebral arterial pulsation on brain viscoelasticity. J Cereb Blood Flow Metab 2020; 40:991-1001. [PMID: 31142226 PMCID: PMC7181097 DOI: 10.1177/0271678x19850936] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 03/29/2019] [Accepted: 04/22/2019] [Indexed: 12/12/2022]
Abstract
In-vivo brain viscoelasticity measured by magnetic resonance elastography (MRE) is a sensitive imaging marker for long-term biophysical changes in brain tissue due to aging and disease; however, it is still unknown whether MRE can reveal short-term periodic alterations of brain viscoelasticity related to cerebral arterial pulsation (CAP). We developed cardiac-gated steady-state MRE (ssMRE) with spiral readout and stroboscopic sampling of continuously induced mechanical vibrations in the brain at 20, 31.25, and 40 Hz frequencies. Maps of magnitude |G*| and phase ϕ of the complex shear modulus were generated by multifrequency dual visco-elasto inversion with a temporal resolution of 40 ms over 4 s. The method was tested in 12 healthy volunteers. During cerebral systole, |G*| decreased by 6.6 ± 1.9% (56 ± 22 Pa, p < 0.001, mean ± SD), whereas ϕ increased by 0.5 ± 0.5% (0.006 ± 0.005 rad, p = 0.002). The effect size of CAP-induced softening slightly decreased with age by 0.10 ± 0.05% per year (p = 0.04), indicating lower cerebral vascular compliance in older individuals. Our data show for the first time that the brain softens and becomes more viscous during systole, possibly due to an effect of CAP-induced arterial expansion and increased blood volume on effective-medium tissue properties. This sensitivity to vascular-solid tissue interactions makes ssMRE potentially useful for detection of cerebral vascular disease.
Collapse
Affiliation(s)
- Felix Schrank
- Department of Radiology, Charité –
Universitätsmedizin Berlin, Berlin, Germany
| | - Carsten Warmuth
- Department of Radiology, Charité –
Universitätsmedizin Berlin, Berlin, Germany
| | - Heiko Tzschätzsch
- Department of Radiology, Charité –
Universitätsmedizin Berlin, Berlin, Germany
| | - Bernhard Kreft
- Department of Radiology, Charité –
Universitätsmedizin Berlin, Berlin, Germany
| | - Sebastian Hirsch
- Berlin Center for Advanced Neuroimaging,
Charité – Universitätsmedizin, Berlin, Germany
| | - Jürgen Braun
- Institute of Medical Informatics,
Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Thomas Elgeti
- Department of Radiology, Charité –
Universitätsmedizin Berlin, Berlin, Germany
| | - Ingolf Sack
- Department of Radiology, Charité –
Universitätsmedizin Berlin, Berlin, Germany
| |
Collapse
|
7
|
Baker WB, Parthasarathy AB, Gannon KP, Kavuri VC, Busch DR, Abramson K, He L, Mesquita RC, Mullen MT, Detre JA, Greenberg JH, Licht DJ, Balu R, Kofke WA, Yodh AG. Noninvasive optical monitoring of critical closing pressure and arteriole compliance in human subjects. J Cereb Blood Flow Metab 2017; 37:2691-2705. [PMID: 28541158 PMCID: PMC5536813 DOI: 10.1177/0271678x17709166] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The critical closing pressure ( CrCP) of the cerebral circulation depends on both tissue intracranial pressure and vasomotor tone. CrCP defines the arterial blood pressure ( ABP) at which cerebral blood flow approaches zero, and their difference ( ABP - CrCP) is an accurate estimate of cerebral perfusion pressure. Here we demonstrate a novel non-invasive technique for continuous monitoring of CrCP at the bedside. The methodology combines optical diffuse correlation spectroscopy (DCS) measurements of pulsatile cerebral blood flow in arterioles with concurrent ABP data during the cardiac cycle. Together, the two waveforms permit calculation of CrCP via the two-compartment Windkessel model for flow in the cerebral arterioles. Measurements of CrCP by optics (DCS) and transcranial Doppler ultrasound (TCD) were carried out in 18 healthy adults; they demonstrated good agreement (R = 0.66, slope = 1.14 ± 0.23) with means of 11.1 ± 5.0 and 13.0 ± 7.5 mmHg, respectively. Additionally, a potentially useful and rarely measured arteriole compliance parameter was derived from the phase difference between ABP and DCS arteriole blood flow waveforms. The measurements provide evidence that DCS signals originate predominantly from arteriole blood flow and are well suited for long-term continuous monitoring of CrCP and assessment of arteriole compliance in the clinic.
Collapse
Affiliation(s)
- Wesley B Baker
- 1 Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, USA
| | - Ashwin B Parthasarathy
- 2 Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, USA.,3 Department of Electrical Engineering, University of South Florida, Tampa, USA
| | - Kimberly P Gannon
- 4 Department of Neurology, University of Pennsylvania, Philadelphia, USA
| | - Venkaiah C Kavuri
- 2 Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, USA
| | - David R Busch
- 5 Division of Neurology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, USA
| | - Kenneth Abramson
- 2 Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, USA
| | - Lian He
- 2 Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, USA
| | | | - Michael T Mullen
- 4 Department of Neurology, University of Pennsylvania, Philadelphia, USA
| | - John A Detre
- 4 Department of Neurology, University of Pennsylvania, Philadelphia, USA
| | - Joel H Greenberg
- 4 Department of Neurology, University of Pennsylvania, Philadelphia, USA
| | - Daniel J Licht
- 5 Division of Neurology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, USA
| | - Ramani Balu
- 4 Department of Neurology, University of Pennsylvania, Philadelphia, USA
| | - W Andrew Kofke
- 1 Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, USA
| | - Arjun G Yodh
- 2 Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, USA
| |
Collapse
|
8
|
Williams H. A unifying hypothesis for hydrocephalus and the Chiari malformations part two: The hydrocephalus filling mechanism. Med Hypotheses 2016; 94:30-9. [DOI: 10.1016/j.mehy.2016.06.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 06/04/2016] [Accepted: 06/09/2016] [Indexed: 10/21/2022]
|
9
|
Beggs CB, Magnano C, Shepherd SJ, Belov P, Ramasamy DP, Hagemeier J, Zivadinov R. Dirty-Appearing White Matter in the Brain is Associated with Altered Cerebrospinal Fluid Pulsatility and Hypertension in Individuals without Neurologic Disease. J Neuroimaging 2015; 26:136-43. [DOI: 10.1111/jon.12249] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 03/04/2015] [Indexed: 11/30/2022] Open
Affiliation(s)
- Clive B. Beggs
- Centre for Infection Control and Biophysics; University of Bradford; Bradford UK
- Department of Neurology, Buffalo Neuroimaging Analysis Center, School of Medicine and Biomedical Sciences; University at Buffalo; Buffalo NY
| | - Christopher Magnano
- Department of Neurology, Buffalo Neuroimaging Analysis Center, School of Medicine and Biomedical Sciences; University at Buffalo; Buffalo NY
- MRI Clinical Translational Research Center, School of Medicine and Biomedical Sciences; University at Buffalo; Buffalo NY
| | - Simon J. Shepherd
- Centre for Infection Control and Biophysics; University of Bradford; Bradford UK
| | - Pavel Belov
- Department of Neurology, Buffalo Neuroimaging Analysis Center, School of Medicine and Biomedical Sciences; University at Buffalo; Buffalo NY
| | - Deepa P. Ramasamy
- Department of Neurology, Buffalo Neuroimaging Analysis Center, School of Medicine and Biomedical Sciences; University at Buffalo; Buffalo NY
- MRI Clinical Translational Research Center, School of Medicine and Biomedical Sciences; University at Buffalo; Buffalo NY
| | - Jesper Hagemeier
- Department of Neurology, Buffalo Neuroimaging Analysis Center, School of Medicine and Biomedical Sciences; University at Buffalo; Buffalo NY
| | - Robert Zivadinov
- Department of Neurology, Buffalo Neuroimaging Analysis Center, School of Medicine and Biomedical Sciences; University at Buffalo; Buffalo NY
- MRI Clinical Translational Research Center, School of Medicine and Biomedical Sciences; University at Buffalo; Buffalo NY
| |
Collapse
|
10
|
Shim JW, Sandlund J, Madsen JR. VEGF: a potential target for hydrocephalus. Cell Tissue Res 2014; 358:667-83. [PMID: 25146955 DOI: 10.1007/s00441-014-1978-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 07/28/2014] [Indexed: 12/13/2022]
Abstract
Growth factors are primarily responsible for the genesis, differentiation and proliferation of cells and maintenance of tissues. Given the central role of growth factors in signaling between cells in health and in disease, it is understandable that disruption of growth factor-mediated molecular signaling can cause diverse phenotypic consequences including cancer and neurological conditions. This review will focus on the specific questions of enlarged cerebral ventricles and hydrocephalus. It is also well known that angiogenic factors, such as vascular endothelial growth factor (VEGF), affect tissue permeability through activation of receptors and adhesion molecules; hence, recent studies showing elevations of this factor in pediatric hydrocephalus led to the demonstration that VEGF can induce ventriculomegaly and altered ependyma when infused in animals. In this review, we discuss recent findings implicating the involvement of biochemical and biophysical factors that can induce a VEGF-mimicking effect in communicating hydrocephalus and pay particular attention to the role of the VEGF system as a potential pharmacological target in the treatment of some cases of hydrocephalus. The source of VEGF secretion in the cerebral ventricles, in periventricular regions and during pathologic events including hydrocephalus following hypoxia and hemorrhage is sought. The review is concluded with a summary of potential non-surgical treatments in preclinical studies suggesting several molecular targets including VEGF for hydrocephalus and related neurological disorders.
Collapse
Affiliation(s)
- Joon W Shim
- Department of Biology, Indiana University-Purdue University Indianapolis, 723 W. Michigan Street SL354, Indianapolis, IN, 46202, USA
| | | | | |
Collapse
|
11
|
Botfield H, Gonzalez AM, Abdullah O, Skjolding AD, Berry M, McAllister JP, Logan A. Decorin prevents the development of juvenile communicating hydrocephalus. ACTA ACUST UNITED AC 2013; 136:2842-58. [PMID: 23983032 DOI: 10.1093/brain/awt203] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
In post-haemorrhagic and other forms of communicating hydrocephalus, cerebrospinal fluid flow and drainage is obstructed by subarachnoid fibrosis in which the potent fibrogenic cytokine transforming growth factor-β has been aetiologically implicated. Here, the hypothesis that the transforming growth factor-β antagonist decorin has therapeutic potential for reducing fibrosis and ventriculomegaly was tested using a rat model of juvenile communicating hydrocephalus. Hydrocephalus was induced by a single basal cistern injection of kaolin in 3-week-old rats, immediately followed by 3 or 14 days of continuous intraventricular infusion of either human recombinant decorin or phosphate-buffered saline (vehicle). Ventricular expansion was measured by magnetic resonance imaging at Day 14. Fibrosis, transforming growth factor-β/Smad2/3 activation and hydrocephalic brain pathology were evaluated at Day 14 and the inflammatory response at Days 3 and 14 by immunohistochemistry and basic histology. Analysis of ventricular size demonstrated the development of hydrocephalus in kaolin-injected rats but also revealed that continuous decorin infusion prevented ventricular enlargement, such that ventricle size remained similar to that in intact control rats. Decorin prevented the increase in transforming growth factor-β1 and phosphorylated Smad2/3 levels throughout the ventricular system after kaolin injection and also inhibited the deposition of the extracellular matrix molecules, laminin and fibronectin in the subarachnoid space. In addition, decorin protected against hydrocephalic brain damage inferred from attenuation of glial and inflammatory reactions. Thus, we conclude that decorin prevented the development of hydrocephalus in juvenile rats by blocking transforming growth factor-β-induced subarachnoid fibrosis and protected against hydrocephalic brain damage. The results suggest that decorin is a potential clinical therapeutic for the treatment of juvenile post-haemorrhagic communicating hydrocephalus.
Collapse
Affiliation(s)
- Hannah Botfield
- Neurotrauma and Neurodegeneration, School of Clinical and Experimental Medicine, University of Birmingham, Edgbaston, B15 2TT, UK.
| | | | | | | | | | | | | |
Collapse
|
12
|
Fushimi Y, Okada T, Yamamoto A, Kanagaki M, Fujimoto K, Togashi K. Timing dependence of peripheral pulse-wave-triggered pulsed arterial spin labeling. NMR IN BIOMEDICINE 2013; 26:1527-1533. [PMID: 23784975 DOI: 10.1002/nbm.2986] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 05/07/2013] [Accepted: 05/14/2013] [Indexed: 06/02/2023]
Abstract
Arterial spin labeling (ASL) has been developed into a useful technique that is capable of quantifying noninvasively local cerebral blood flow (CBF) using the water molecules in arterial blood as diffusible tracers. Pulsed ASL (PASL) is more strongly affected than continuous ASL (CASL) by cardiac pulsation, because the tag bolus is shorter than the cardiac cycle in most cases. No reports have yet clarified the effects of multiple cardiac phases on the quantification of CBF in PASL when triggering is used. Fourteen subjects participated in this study. Peripheral pulse-wave-triggered (PPWT)-ASL was performed at various time points at the carotid artery (delay 0 ms, second point, foot, peak and tail) and compared with nontriggered (NT)-ASL. Regions of interest (ROIs) were applied based on the anterior, middle and posterior cerebral artery (ACA, MCA, PCA) territories, and CBFs were compared among different time points and ROIs. PPWT-ASL strongly affects CBF values compared with NT-ASL in ACA and MCA territories, especially when measured at the foot of the carotid artery flow phase. CBF_NT was assumed to lie approximately between the minimum and maximum CBFs, with clear statistical significance in several ROIs at several time points of PPWT-ASL, and CBF_NT was assumed to resemble 'randomly triggered' PPWT-ASL. In conclusion, PPWT-ASL strongly affects CBF values compared with NT-ASL, particularly at the foot of the carotid artery flow in ACA and MCA territories.
Collapse
Affiliation(s)
- Yasutaka Fushimi
- Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | | | | | | | | | | |
Collapse
|
13
|
Shulyakov AV, Buist RJ, Del Bigio MR. Intracranial Biomechanics of Acute Experimental Hydrocephalus in Live Rats. Neurosurgery 2012; 71:1032-40. [DOI: 10.1227/neu.0b013e3182690a0c] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
|