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Edrisnia H, Sharbatdar M. Numerical analysis of the effect of Syringomyelia on cerebrospinal fluid dynamics. Heliyon 2024; 10:e37067. [PMID: 39319127 PMCID: PMC11419872 DOI: 10.1016/j.heliyon.2024.e37067] [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: 06/22/2024] [Revised: 08/19/2024] [Accepted: 08/27/2024] [Indexed: 09/26/2024] Open
Abstract
Spinal cord enlargement (SCE) includes conditions such as Syringomyelia, tumors, and tumor-like cases of demyelination, edema, or inflammation. These conditions involve fluid-filled cysts, known as syrinx, or masses of tissue, referred to as tumors, which cause increased pressure within the spinal cord (SC) and obstruct cerebrospinal fluid (CSF) circulation. To assess the impact of SCE location and diameter, we constructed fifteen computational SC models, each featuring a SCE placed in one of five probable locations with 20 %, 40 %, and 60 % stenosis. Our objective was to investigate how the location, diameter, and length of the SCE influence CSF velocity pattern and to identify the most critical location in the SC associated with this condition. The results indicated a velocity increase of 0.5 cm/(s) near models with 60 % stenosis. Importantly, SCE located from T1 to T5 exhibit a more pronounced reduction, exceeding 6.5, in the Womersley number. Our finding suggests that this region is the most vulnerable for SCE formation due to its significant impact on fluid circulation. The identification of specific locations within the SC associated with heightened risk can contribute to an improved understanding, treatment and management of SCE.
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Affiliation(s)
- Hadis Edrisnia
- Faculty of Mechanical Engineering, K. N. Toosi University of Technology, Tehran, 19991-43344, Iran
| | - Mahkame Sharbatdar
- Faculty of Mechanical Engineering, K. N. Toosi University of Technology, Tehran, 19991-43344, Iran
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2
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Torlakcik H, Sevim S, Alves P, Mattmann M, Llacer-Wintle J, Pinto M, Moreira R, Flouris AD, Landers FC, Chen XZ, Puigmartí-Luis J, Boehler Q, Mayor TS, Kim M, Nelson BJ, Pané S. Magnetically Guided Microcatheter for Targeted Injection of Magnetic Particle Swarms. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2404061. [PMID: 39119930 DOI: 10.1002/advs.202404061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 07/26/2024] [Indexed: 08/10/2024]
Abstract
The initial delivery of small-scale magnetic devices such as microrobots is a key, but often overlooked, aspect for their use in clinical applications. The deployment of these devices within the dynamic environment of the human body presents significant challenges due to their dispersion caused by circulatory flows. Here, a method is introduced to effectively deliver a swarm of magnetic nanoparticles in fluidic flows. This approach integrates a magnetically navigated robotic microcatheter equipped with a reservoir for storing the magnetic nanoparticles. The microfluidic flow within the reservoir facilitates the injection of magnetic nanoparticles into the fluid stream, and a magnetic field gradient guides the swarm through the oscillatory flow to a target site. The microcatheter and reservoir are engineered to enable magnetic steering and injection of the magnetic nanoparticles. To demonstrate this approach, experiments are conducted utilizing a spinal cord phantom simulating intrathecal catheter delivery for applications in the central nervous system. These results demonstrate that the proposed microcatheter successfully concentrates nanoparticles near the desired location through the precise manipulation of magnetic field gradients, offering a promising solution for the controlled deployment of untethered magnetic micro-/nanodevices within the complex physiological circulatory systems of the human body.
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Affiliation(s)
- Harun Torlakcik
- Multi-Scale Robotics Lab, Institute of Robotics and Intelligent Systems, ETH Zurich, Tannenstrasse 3, Zurich, 8092, Switzerland
| | - Semih Sevim
- Multi-Scale Robotics Lab, Institute of Robotics and Intelligent Systems, ETH Zurich, Tannenstrasse 3, Zurich, 8092, Switzerland
| | - Pedro Alves
- Transport Phenomena Research Centre (CEFT), Engineering Faculty, Porto University, Porto, 4200, Portugal
- Associate Laboratory in Chemical Engineering (ALICE), Engineering Faculty, Porto University, Porto, 4200, Portugal
| | - Michael Mattmann
- Multi-Scale Robotics Lab, Institute of Robotics and Intelligent Systems, ETH Zurich, Tannenstrasse 3, Zurich, 8092, Switzerland
| | - Joaquim Llacer-Wintle
- Multi-Scale Robotics Lab, Institute of Robotics and Intelligent Systems, ETH Zurich, Tannenstrasse 3, Zurich, 8092, Switzerland
| | | | | | - Andreas D Flouris
- FAME Laboratory, Department of Exercise Science, University of Thessaly, Trikala, Karies, 42100, Greece
| | - Fabian C Landers
- Multi-Scale Robotics Lab, Institute of Robotics and Intelligent Systems, ETH Zurich, Tannenstrasse 3, Zurich, 8092, Switzerland
| | - Xiang-Zhong Chen
- Institute of Optoelectronics, State Key Laboratory of Photovoltaic Science and Technology, Shanghai Frontiers Science Research Base of Intelligent Optoelectronics and Perception, Fudan University, Shanghai, 200433, P. R. China
- Yiwu Research Institute of Fudan University, Yiwu, 322000, P. R. China
| | - Josep Puigmartí-Luis
- Departament de Ciència dels Materials i Química Física, Institut de Química Teòrica i Computacional, University of Barcelona, Martí i Franquès, 1, Barcelona, 08028, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, Barcelona, 08010, Spain
| | - Quentin Boehler
- Multi-Scale Robotics Lab, Institute of Robotics and Intelligent Systems, ETH Zurich, Tannenstrasse 3, Zurich, 8092, Switzerland
| | - Tiago Sotto Mayor
- Transport Phenomena Research Centre (CEFT), Engineering Faculty, Porto University, Porto, 4200, Portugal
- Associate Laboratory in Chemical Engineering (ALICE), Engineering Faculty, Porto University, Porto, 4200, Portugal
| | - Minsoo Kim
- Multi-Scale Robotics Lab, Institute of Robotics and Intelligent Systems, ETH Zurich, Tannenstrasse 3, Zurich, 8092, Switzerland
| | - Bradley J Nelson
- Multi-Scale Robotics Lab, Institute of Robotics and Intelligent Systems, ETH Zurich, Tannenstrasse 3, Zurich, 8092, Switzerland
| | - Salvador Pané
- Multi-Scale Robotics Lab, Institute of Robotics and Intelligent Systems, ETH Zurich, Tannenstrasse 3, Zurich, 8092, Switzerland
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3
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Hladky SB, Barrand MA. Regulation of brain fluid volumes and pressures: basic principles, intracranial hypertension, ventriculomegaly and hydrocephalus. Fluids Barriers CNS 2024; 21:57. [PMID: 39020364 PMCID: PMC11253534 DOI: 10.1186/s12987-024-00532-w] [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: 12/16/2023] [Accepted: 03/21/2024] [Indexed: 07/19/2024] Open
Abstract
The principles of cerebrospinal fluid (CSF) production, circulation and outflow and regulation of fluid volumes and pressures in the normal brain are summarised. Abnormalities in these aspects in intracranial hypertension, ventriculomegaly and hydrocephalus are discussed. The brain parenchyma has a cellular framework with interstitial fluid (ISF) in the intervening spaces. Framework stress and interstitial fluid pressure (ISFP) combined provide the total stress which, after allowing for gravity, normally equals intracerebral pressure (ICP) with gradients of total stress too small to measure. Fluid pressure may differ from ICP in the parenchyma and collapsed subarachnoid spaces when the parenchyma presses against the meninges. Fluid pressure gradients determine fluid movements. In adults, restricting CSF outflow from subarachnoid spaces produces intracranial hypertension which, when CSF volumes change very little, is called idiopathic intracranial hypertension (iIH). Raised ICP in iIH is accompanied by increased venous sinus pressure, though which is cause and which effect is unclear. In infants with growing skulls, restriction in outflow leads to increased head and CSF volumes. In adults, ventriculomegaly can arise due to cerebral atrophy or, in hydrocephalus, to obstructions to intracranial CSF flow. In non-communicating hydrocephalus, flow through or out of the ventricles is somehow obstructed, whereas in communicating hydrocephalus, the obstruction is somewhere between the cisterna magna and cranial sites of outflow. When normal outflow routes are obstructed, continued CSF production in the ventricles may be partially balanced by outflow through the parenchyma via an oedematous periventricular layer and perivascular spaces. In adults, secondary hydrocephalus with raised ICP results from obvious obstructions to flow. By contrast, with the more subtly obstructed flow seen in normal pressure hydrocephalus (NPH), fluid pressure must be reduced elsewhere, e.g. in some subarachnoid spaces. In idiopathic NPH, where ventriculomegaly is accompanied by gait disturbance, dementia and/or urinary incontinence, the functional deficits can sometimes be reversed by shunting or third ventriculostomy. Parenchymal shrinkage is irreversible in late stage hydrocephalus with cellular framework loss but may not occur in early stages, whether by exclusion of fluid or otherwise. Further studies that are needed to explain the development of hydrocephalus are outlined.
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Affiliation(s)
- Stephen B Hladky
- Department of Pharmacology, Tennis Court Rd, Cambridge, CB2 1PD, UK.
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4
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Alaminos-Quesada J, Gutiérrez-Montes C, Coenen W, Sánchez A. Stationary flow driven by non-sinusoidal time-periodic pressure gradients in wavy-walled channels. APPLIED MATHEMATICAL MODELLING 2023; 122:693-705. [PMID: 37485297 PMCID: PMC10359023 DOI: 10.1016/j.apm.2023.06.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/25/2023]
Abstract
The classical problem of secondary flow driven by a sinusoidally varying pressure gradient is extended here to address periodic pressure gradients of complex waveform, which are present in many oscillatory physiological flows. A slender two-dimensional wavy-walled channel is selected as a canonical model problem. Following standard steady-streaming analyses, valid for small values of the ratio ε of the stroke length of the pulsatile motion to the channel wavelength, the spatially periodic flow is described in terms of power-law expansions of ε , with the Womersley number assumed to be of order unity. The solution found at leading order involves a time-periodic velocity with a zero time-averaged value at any given point. As in the case of a sinusoidal pressure gradient, effects of inertia enter at the following order to induce a steady flow in the form of recirculating vortices with zero net flow rate. An improved two-term asymptotic description of this secondary flow is sought by carrying the analysis to the following order. It is found that, when the pressure gradient has a waveform with multiple harmonics, the resulting velocity corrections display a nonzero flow rate, not present in the single-frequency case, which enables stationary convective transport along the channel. Direct numerical simulations for values of ε of order unity are used to investigate effects of inertia and delineate the range of validity of the asymptotic limit ε ≪ 1 . The comparisons of the time-averaged velocity obtained numerically with the two-term asymptotic description reveals that the latter remains remarkably accurate for values of ε exceeding 0.5. As an illustrative example, the results of the model problem are used to investigate the cerebrospinal-fluid flow driven along the spinal canal by the cardiac and respiratory cycles, characterized by markedly non-sinusoidal waveforms.
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Affiliation(s)
- J. Alaminos-Quesada
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, 92093-0411, California, USA
| | - C. Gutiérrez-Montes
- Department of Mechanical and Mining Engineering, University of Jaén, 23071, Spain
- Andalusian Institute for Earth System Research, University of Jaén, Campus de las Lagunillas, 23071 Jaén, Spain
| | - W. Coenen
- Grupo de Mecánica de Fluidos, Universidad Carlos III de Madrid, Leganés, 28911, Spain
| | - A.L. Sánchez
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, 92093-0411, California, USA
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5
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Alaminos-Quesada J, Lawrence J, Coenen W, Sánchez A. Oscillating viscous flow past a streamwise linear array of circular cylinders. JOURNAL OF FLUID MECHANICS 2023; 959:A39. [PMID: 37206991 PMCID: PMC10191390 DOI: 10.1017/jfm.2023.178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
This paper addresses the viscous flow developing about an array of equally spaced identical circular cylinders aligned with an incompressible fluid stream whose velocity oscillates periodically in time. The focus of the analysis is on harmonically oscillating flows with stroke lengths that are comparable to or smaller than the cylinder radius, such that the flow remains two-dimensional, time-periodic and symmetric with respect to the centreline. Specific consideration is given to the limit of asymptotically small stroke lengths, in which the flow is harmonic at leading order, with the first-order corrections exhibiting a steady-streaming component, which is computed here along with the accompanying Stokes drift. As in the familiar case of oscillating flow over a single cylinder, for small stroke lengths, the associated time-averaged Lagrangian velocity field, given by the sum of the steady-streaming and Stokes-drift components, displays recirculating vortices, which are quantified for different values of the two relevant controlling parameters, namely, the Womersley number and the ratio of the inter-cylinder distance to the cylinder radius. Comparisons with results of direct numerical simulations indicate that the description of the Lagrangian mean flow for infinitesimally small values of the stroke length remains reasonably accurate even when the stroke length is comparable to the cylinder radius. The numerical integrations are also used to quantify the streamwise flow rate induced by the presence of the cylinder array in cases where the periodic surrounding motion is driven by an anharmonic pressure gradient, a problem of interest in connection with the oscillating flow of cerebrospinal fluid around the nerve roots located along the spinal canal.
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Affiliation(s)
- J. Alaminos-Quesada
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA 92093, USA
| | - J.J. Lawrence
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA 92093, USA
| | - W. Coenen
- Grupo de Mecánica de Fluidos, Departamento de Ingeniería Térmica y de Fluidos, Universidad Carlos III de Madrid, 28911 Leganés, Madrid, Spain
| | - A.L. Sánchez
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA 92093, USA
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6
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Pan S, Yang PH, DeFreitas D, Ramagiri S, Bayguinov PO, Hacker CD, Snyder AZ, Wilborn J, Huang H, Koller GM, Raval DK, Halupnik GL, Sviben S, Achilefu S, Tang R, Haller G, Quirk JD, Fitzpatrick JAJ, Esakky P, Strahle JM. Gold nanoparticle-enhanced X-ray microtomography of the rodent reveals region-specific cerebrospinal fluid circulation in the brain. Nat Commun 2023; 14:453. [PMID: 36707519 PMCID: PMC9883388 DOI: 10.1038/s41467-023-36083-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 01/12/2023] [Indexed: 01/28/2023] Open
Abstract
Cerebrospinal fluid (CSF) is essential for the development and function of the central nervous system (CNS). However, the brain and its interstitium have largely been thought of as a single entity through which CSF circulates, and it is not known whether specific cell populations within the CNS preferentially interact with the CSF. Here, we develop a technique for CSF tracking, gold nanoparticle-enhanced X-ray microtomography, to achieve micrometer-scale resolution visualization of CSF circulation patterns during development. Using this method and subsequent histological analysis in rodents, we identify previously uncharacterized CSF pathways from the subarachnoid space (particularly the basal cisterns) that mediate CSF-parenchymal interactions involving 24 functional-anatomic cell groupings in the brain and spinal cord. CSF distribution to these areas is largely restricted to early development and is altered in posthemorrhagic hydrocephalus. Our study also presents particle size-dependent CSF circulation patterns through the CNS including interaction between neurons and small CSF tracers, but not large CSF tracers. These findings have implications for understanding the biological basis of normal brain development and the pathogenesis of a broad range of disease states, including hydrocephalus.
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Affiliation(s)
- Shelei Pan
- Department of Neurosurgery, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Peter H Yang
- Department of Neurosurgery, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Dakota DeFreitas
- Department of Neurosurgery, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Sruthi Ramagiri
- Department of Neurosurgery, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Peter O Bayguinov
- Washington University Center for Cellular Imaging, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Carl D Hacker
- Department of Neurosurgery, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Abraham Z Snyder
- Department of Radiology, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
- Department of Neurology, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Jackson Wilborn
- Department of Neurosurgery, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Hengbo Huang
- Department of Radiology, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Gretchen M Koller
- Department of Neurosurgery, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Dhvanii K Raval
- Department of Neurosurgery, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Grace L Halupnik
- Department of Neurosurgery, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Sanja Sviben
- Washington University Center for Cellular Imaging, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Samuel Achilefu
- Department of Biomedical Engineering, UT Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Rui Tang
- Department of Radiology, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Gabriel Haller
- Department of Neurosurgery, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
- Department of Neurology, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
- Department of Genetics, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - James D Quirk
- Department of Radiology, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - James A J Fitzpatrick
- Washington University Center for Cellular Imaging, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
- Department of Neuroscience, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
- Department of Cell Biology and Physiology, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Prabagaran Esakky
- Department of Neurosurgery, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Jennifer M Strahle
- Department of Neurosurgery, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA.
- Department of Orthopedic Surgery, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA.
- Department of Pediatrics, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA.
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7
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Vandenbulcke S, De Pauw T, Dewaele F, Degroote J, Segers P. Computational fluid dynamics model to predict the dynamical behavior of the cerebrospinal fluid through implementation of physiological boundary conditions. Front Bioeng Biotechnol 2022; 10:1040517. [PMID: 36483773 PMCID: PMC9722737 DOI: 10.3389/fbioe.2022.1040517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 11/11/2022] [Indexed: 10/22/2023] Open
Abstract
Cerebrospinal fluid (CSF) dynamics play an important role in maintaining a stable central nervous system environment and are influenced by different physiological processes. Multiple studies have investigated these processes but the impact of each of them on CSF flow is not well understood. A deeper insight into the CSF dynamics and the processes impacting them is crucial to better understand neurological disorders such as hydrocephalus, Chiari malformation, and intracranial hypertension. This study presents a 3D computational fluid dynamics (CFD) model which incorporates physiological processes as boundary conditions. CSF production and pulsatile arterial and venous volume changes are implemented as inlet boundary conditions. At the outlets, 2-element windkessel models are imposed to simulate CSF compliance and absorption. The total compliance is first tuned using a 0D model to obtain physiological pressure pulsations. Then, simulation results are compared with in vivo flow measurements in the spinal subarachnoid space (SAS) and cerebral aqueduct, and intracranial pressure values reported in the literature. Finally, the impact of the distribution of and total compliance on CSF pressures and velocities is evaluated. Without respiration effects, compliance of 0.17 ml/mmHg yielded pressure pulsations with an amplitude of 5 mmHg and an average value within the physiological range of 7-15 mmHg. Also, model flow rates were found to be in good agreement with reported values. However, when adding respiration effects, similar pressure amplitudes required an increase of compliance value to 0.51 ml/mmHg, which is within the range of 0.4-1.2 ml/mmHg measured in vivo. Moreover, altering the distribution of compliance over the four different outlets impacted the local flow, including the flow through the foramen magnum. The contribution of compliance to each outlet was directly proportional to the outflow at that outlet. Meanwhile, the value of total compliance impacted intracranial pressure. In conclusion, a computational model of the CSF has been developed that can simulate CSF pressures and velocities by incorporating boundary conditions based on physiological processes. By tuning these boundary conditions, we were able to obtain CSF pressures and flows within the physiological range.
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Affiliation(s)
- Sarah Vandenbulcke
- Institute of Biomedical Engineering and Technology (IBiTech-bioMMeda), Department of Electronics and Information Systems, Ghent University, Ghent, Belgium
| | - Tim De Pauw
- Department of Neurosurgery, Ghent University Hospital, Ghent, Belgium
| | - Frank Dewaele
- Department of Neurosurgery, Ghent University Hospital, Ghent, Belgium
| | - Joris Degroote
- Department of Electromechanical Systems and Metal Engineering, Ghent University, Ghent, Belgium
| | - Patrick Segers
- Institute of Biomedical Engineering and Technology (IBiTech-bioMMeda), Department of Electronics and Information Systems, Ghent University, Ghent, Belgium
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8
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Gutiérrez-Montes C, Coenen W, Vidorreta M, Sincomb S, Martínez-Bazán C, Sánchez AL, Haughton V. Effect of Normal Breathing on the Movement of CSF in the Spinal Subarachnoid Space. AJNR Am J Neuroradiol 2022; 43:1369-1374. [PMID: 35981761 PMCID: PMC9451622 DOI: 10.3174/ajnr.a7603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 06/24/2022] [Indexed: 01/26/2023]
Abstract
BACKGROUND AND PURPOSE Forced respirations reportedly have an effect on CSF movement in the spinal canal. We studied respiratory-related CSF motion during normal respiration. MATERIALS AND METHODS Six healthy subjects breathed at their normal rate with a visual guide to ensure an unchanging rhythm. Respiratory-gated phase-contrast MR flow images were acquired at 5 selected axial planes along the spine. At each spinal level, we computed the flow rate voxelwise in the spinal canal, together with the associated stroke volume. From these data, we computed the periodic volume changes of spinal segments. A phantom was used to quantify the effect of respiration-related magnetic susceptibility changes on the velocity data measured. RESULTS At each level, CSF moved cephalad during inhalation and caudad during expiration. While the general pattern of fluid movement was the same in the 6 subjects, the flow rates, stroke volumes, and spine segment volume changes varied among subjects. Peak flow rates ranged from 0.60 to 1.59 mL/s in the cervical region, 0.46 to 3.17 mL/s in the thoracic region, and 0.75 to 3.64 mL/s in the lumbar region. The differences in flow rates along the canal yielded cyclic volume variations of spine segments that were largest in the lumbar spine, ranging from 0.76 to 3.07 mL among subjects. In the phantom study, flow velocities oscillated periodically during the respiratory cycle by up to 0.02 cm/s or 0.5%. CONCLUSIONS Respiratory-gated measurements of the CSF motion in the spinal canal showed cyclic oscillatory movements of spinal fluid correlated to the breathing pattern.
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Affiliation(s)
- C Gutiérrez-Montes
- From the Department of Mechanical and Mining Engineering (C.G.-M.), University of Jaén, Jaén, Andalucía, Spain
| | - W Coenen
- Grupo de Mecánica de Fluidos, Departamento de Ingeniería Térmica y de Fluidos (W.C.), Universidad Carlos III de Madrid, Madrid, Spain
| | | | - S Sincomb
- Department of Mechanical and Aerospace Engineering (S.S., A.L.S.), University of California San Diego, San Diego, California
| | - C Martínez-Bazán
- Department of Structural Mechanics and Hydraulic Engineering (C.M.-B.), University of Granada, Granada, Spain
| | - A L Sánchez
- Department of Mechanical and Aerospace Engineering (S.S., A.L.S.), University of California San Diego, San Diego, California
| | - V Haughton
- Department of Radiology (V.H.), School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin
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9
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Yepes-Calderon F, McComb JG. Accurate image-based CSF volume calculation of the lateral ventricles. Sci Rep 2022; 12:12115. [PMID: 35840587 PMCID: PMC9287564 DOI: 10.1038/s41598-022-15995-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Accepted: 07/04/2022] [Indexed: 11/28/2022] Open
Abstract
The size/volume of the brain’s ventricles is essential in diagnosing and treating many neurological disorders, with various forms of hydrocephalus being some of the most common. Initial ventricular size and changes, if any, in response to disease progression or therapeutic intervention are monitored by serial imaging methods. Significant variance in ventricular size is readily noted, but small incremental changes can be challenging to appreciate. We have previously reported using artificial intelligence to determine ventricular volume. The values obtained were compared with those calculated using the inaccurate manual segmentation as the “gold standard”. This document introduces a strategy to measure ventricular volumes where manual segmentation is not employed to validate the estimations. Instead, we created 3D printed models that mimic the lateral ventricles and measured those 3D models’ volume with a tuned water displacement device. The 3D models are placed in a gel and taken to the magnetic resonance scanner. Images extracted from the phantoms are fed to an artificial intelligence-based algorithm. The volumes yielded by the automation must equal those yielded by water displacement to assert validation. Then, we provide certified volumes for subjects in the age range (1–114) months old and two hydrocephalus patients.
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Affiliation(s)
- Fernando Yepes-Calderon
- Science Based Platforms LLC, R&D, 604 Beach CT, Fort Pierce, 34950, USA. .,GYM Group SA, R&D, Carrera 78A 6-58, Cali, Valle del Cauca, 76001, Colombia.
| | - J Gordon McComb
- Division of Neurosurgery, Children Hospital Los Angeles, Los Angeles , 90027, USA.,Keck School of Medicine, University of Southern California, Los Angeles, 90033, USA
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10
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Seiner A, Burla GKR, Shrestha D, Bowen M, Horvath JD, Martin BA. Investigation of Human Intrathecal Solute Transport Dynamics Using a Novel in vitro Cerebrospinal Fluid System Analog. FRONTIERS IN NEUROIMAGING 2022; 1:879098. [PMID: 37555174 PMCID: PMC10406265 DOI: 10.3389/fnimg.2022.879098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 05/24/2022] [Indexed: 08/10/2023]
Abstract
BACKGROUND Understanding the relationship between cerebrospinal fluid (CSF) dynamics and intrathecal drug delivery (ITDD) injection parameters is essential to improve treatment of central nervous system (CNS) disorders. METHODS An anatomically detailed in vitro model of the complete CSF system was constructed. Patient-specific cardiac- and respiratory-induced CSF oscillations were input to the model in the subarachnoid space and within the ventricles. CSF production was input at the lateral ventricles and CSF absorption at the superior sagittal sinus. A model small molecule simulated drug product containing fluorescein was imaged within the system over a period of 3-h post-lumbar ITDD injections and used to quantify the impact of (a) bolus injection volume and rate, (b) post-injection flush volume, rate, and timing, (c) injection location, and (d) type of injection device. For each experiment, neuraxial distribution of fluorescein in terms of spatial temporal concentration, area-under-the-curve (AUC), and percent of injected dose (%ID) to the brain was quantified at a time point 3-h post-injection. RESULTS For all experiments conducted with ITDD administration in the lumbar spine, %ID to the brain did not exceed 11.6% at a time point 3-h post-injection. Addition of a 12 mL flush slightly increased solute transport to the brain up to +3.9%ID compared to without a flush (p < 0.01). Implantation of a lumbar catheter with the tip at an equivalent location to the lumbar placed needle, but with rostral tip orientation, resulted in a small improvement of 1.5%ID to the brain (p < 0.05). An increase of bolus volume from 5 to 20 mL improved solute transport to the brain from 5.0 to 6.3%ID, but this improvement was not statistically significant. Increasing bolus injection rate from 5 to 13.3 mL/min lacked improvement of solute transport to the brain, with a value of 6.3 compared to 5.7%ID. CONCLUSION The in vitro modeling approach allowed precisely controlled and repeatable parametric investigation of ITDD injection protocols and devices. In combination, the results predict that parametric changes in lumbar spine ITDD-injection related parameters and devices can alter %ID to the brain and be tuned to optimize therapeutic benefit to CNS targets.
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Affiliation(s)
- Akari Seiner
- Department of Chemical and Biological Engineering, University of Idaho, Moscow, ID, United States
| | | | - Dev Shrestha
- Department of Chemical and Biological Engineering, University of Idaho, Moscow, ID, United States
| | - Mayumi Bowen
- Genentech, Inc., A Member of the Roche Group, South San Francisco, CA, United States
| | - Joshua D. Horvath
- Genentech, Inc., A Member of the Roche Group, South San Francisco, CA, United States
| | - Bryn A. Martin
- Department of Chemical and Biological Engineering, University of Idaho, Moscow, ID, United States
- Alcyone Therapeutics Inc., Lowell, MA, United States
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11
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de Freitas RM, Capogrosso M, Nomura T, Milosevic M. Optimizing sensory fiber activation during cervical transcutaneous spinal stimulation using different electrode configurations: A computational analysis. Artif Organs 2022; 46:2015-2026. [PMID: 35642297 DOI: 10.1111/aor.14323] [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: 02/25/2022] [Revised: 04/21/2022] [Accepted: 05/18/2022] [Indexed: 11/30/2022]
Abstract
BACKGROUND Cervical transcutaneous spinal cord stimulation (tSCS) is a rehabilitation tool which has been used to promote upper-limb motor recovery after spinal cord injury. Importantly, optimizing sensory fiber activation at specific spinal segments could enable activity-dependent neuromodulation during rehabilitation. METHODS An anatomically realistic cervical tSCS computational model was used to analyze the activation of α-motor and Aα-sensory fibers at C7 and C8 spinal segments using nine cathode electrode configurations. Specifically, the cathode was simulated at three vertebral level positions: C6, C7, and T1; and in three sizes: 5.0 x 5.0, 3.5 x 3.5; and 2.5 x 2.5 cm2 , while the anode was on the anterior neck. Finite element method was used to estimate the electric potential distribution along α-motor and Aα-sensory fibers, and computational models were applied to simulate the fiber membrane dynamics during tSCS. The minimum stimulation intensity necessary to activate the fibers (activation threshold) was estimated and compared across cathode configurations in an effort to optimize sensory fiber activation. RESULTS Our results showed that nerve fibers at both C7 and C8 spinal segments were recruited at lower stimulation intensities when the cathode was positioned over the C7 or T1 vertebra compared with the C6 position. Sensory fibers were activated at lower stimulation intensities using smaller electrodes, which could also affect the degree of nerve fiber activation across different positions. Importantly, Aα-sensory fibers were consistently recruited before α-motor fibers. CONCLUSIONS These results imply that cathode positioning could help optimize preferential activation of hand muscles during cervical tSCS.
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Affiliation(s)
- Roberto M de Freitas
- Graduate School of Engineering Science, Department of Mechanical Science and Bioengineering, Osaka University, Japan
| | - Marco Capogrosso
- Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, USA.,Rehab and Neural Engineering Labs, University of Pittsburgh, Pittsburgh, USA.,Department of Bioengineering, University of Pittsburgh, Pittsburgh, USA
| | - Taishin Nomura
- Graduate School of Engineering Science, Department of Mechanical Science and Bioengineering, Osaka University, Japan
| | - Matija Milosevic
- Graduate School of Engineering Science, Department of Mechanical Science and Bioengineering, Osaka University, Japan
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12
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Saleh MAA, Bloemberg JS, Elassaiss-Schaap J, de Lange ECM. Drug Distribution in Brain and Cerebrospinal Fluids in Relation to IC 50 Values in Aging and Alzheimer's Disease, Using the Physiologically Based LeiCNS-PK3.0 Model. Pharm Res 2022; 39:1303-1319. [PMID: 35606598 PMCID: PMC9246802 DOI: 10.1007/s11095-022-03281-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 04/27/2022] [Indexed: 12/02/2022]
Abstract
Background Very little knowledge exists on the impact of Alzheimer’s disease on the CNS target site pharmacokinetics (PK). Aim To predict the CNS PK of cognitively healthy young and elderly and of Alzheimer’s patients using the physiologically based LeiCNS-PK3.0 model. Methods LeiCNS-PK3.0 was used to predict the PK profiles in brain extracellular (brainECF) and intracellular (brainICF) fluids and cerebrospinal fluid of the subarachnoid space (CSFSAS) of donepezil, galantamine, memantine, rivastigmine, and semagacestat in young, elderly, and Alzheimer’s patients. The physiological parameters of LeiCNS-PK3.0 were adapted for aging and Alzheimer’s based on an extensive literature search. The CNS PK profiles at plateau for clinical dose regimens were related to in vitro IC50 values of acetylcholinesterase, butyrylcholinesterase, N-methyl-D-aspartate, or gamma-secretase. Results The PK profiles of all drugs differed between the CNS compartments regarding plateau levels and fluctuation. BrainECF, brainICF and CSFSAS PK profile relationships were different between the drugs. Aging and Alzheimer’s had little to no impact on CNS PK. Rivastigmine acetylcholinesterase IC50 values were not reached. Semagacestat brain PK plateau levels were below the IC50 of gamma-secretase for half of the interdose interval, unlike CSFSAS PK profiles that were consistently above IC50. Conclusion This study provides insights into the relations between CNS compartments PK profiles, including target sites. CSFSAS PK appears to be an unreliable predictor of brain PK. Also, despite extensive changes in blood-brain barrier and brain properties in Alzheimer’s, this study shows that the impact of aging and Alzheimer’s pathology on CNS distribution of the five drugs is insignificant. Supplementary Information The online version contains supplementary material available at 10.1007/s11095-022-03281-3.
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Affiliation(s)
- Mohammed A A Saleh
- Division of Systems Pharmacology and Pharmacy, Leiden Academic Center for Drug Research, Leiden University, Leiden, The Netherlands
| | - Julia S Bloemberg
- Division of Systems Pharmacology and Pharmacy, Leiden Academic Center for Drug Research, Leiden University, Leiden, The Netherlands
| | - Jeroen Elassaiss-Schaap
- Division of Systems Pharmacology and Pharmacy, Leiden Academic Center for Drug Research, Leiden University, Leiden, The Netherlands
- PD-value B.V., Houten, The Netherlands
| | - Elizabeth C M de Lange
- Division of Systems Pharmacology and Pharmacy, Leiden Academic Center for Drug Research, Leiden University, Leiden, The Netherlands.
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13
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de Freitas RM, Capogrosso M, Nomura T, Milosevic M. Preferential activation of proprioceptive and cutaneous sensory fibers compared to motor fibers during cervical transcutaneous spinal cord stimulation: A computational study. J Neural Eng 2022; 19. [PMID: 35472720 DOI: 10.1088/1741-2552/ac6a7c] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 04/25/2022] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Cervical transcutaneous spinal cord stimulation (tSCS) is a promising technology that can support motor function recovery of upper-limbs after spinal cord injury. Its efficacy may depend on the ability to recruit sensory afferents, conveying excitatory inputs onto motoneurons. Therefore, understanding its physiological mechanisms is critical to accelerate its development towards clinical applications. In this study, we used an anatomically realistic cervical tSCS computational model to compare α-motor, Aα-sensory, and Aβ-sensory fiber activation thresholds and activation sites. APPROACH We developed a 3D geometry of the cervical body and tSCS electrodes with a cathode centred at the C7 spinous process and an anode placed over the anterior neck. The geometrical model was used to estimate the electric potential distributions along motor and sensory fiber trajectories at the C7 spinal level using a finite element method. We implemented dedicated motor and sensory fiber models to simulate the α-motor and Aα-sensory fibers using 12, 16, and 20 µm diameter fibers, and Aβ-sensory fibers using 6, 9, and 12 µm diameter fibers. We estimated nerve fiber activation thresholds and sites for a 2 ms monophasic stimulating pulse and compared them across the fiber groups. MAIN RESULTS Our results showed lower activation thresholds of Aα- and Aβ-sensory fibers compared with α-motor fibers, suggesting preferential sensory fiber activation. We also found no differences between activation thresholds of Aα-sensory and large Aβ-sensory fibers, implying their co-activation. The activation sites were located at the dorsal and ventral root levels. SIGNIFICANCE Using a realistic computational model, we demonstrated preferential activation of dorsal root Aα- and Aβ-sensory fibers compared with ventral root α-motor fibers during cervical tSCS. These findings suggest high proprioceptive and cutaneous contributions to neural activations during cervical tSCS, which inform the underlying mechanisms of upper-limb functional motor recovery.
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Affiliation(s)
- Roberto M de Freitas
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, 560-8531, JAPAN
| | - Marco Capogrosso
- University of Pittsburgh, 3520, Fifth Av., Pittsburgh, Pennsylvania, 15261, UNITED STATES
| | - Taishin Nomura
- Department of Mechanical Science and Bioengineering, Osaka University, Machikaneyama 1-3, Toyonaka City, Osaka 560- 8531, Toyonaka, 5608531, JAPAN
| | - Matija Milosevic
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, J520, Toyonaka, Osaka, 560-8531, JAPAN
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14
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Khani M, Burla GKR, Sass LR, Arters ON, Xing T, Wu H, Martin BA. Human in silico trials for parametric computational fluid dynamics investigation of cerebrospinal fluid drug delivery: impact of injection location, injection protocol, and physiology. Fluids Barriers CNS 2022; 19:8. [PMID: 35090516 PMCID: PMC8796513 DOI: 10.1186/s12987-022-00304-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 01/03/2022] [Indexed: 11/11/2022] Open
Abstract
Background Intrathecal drug delivery has a significant role in pain management and central nervous system (CNS) disease therapeutics. A fluid-physics based tool to assist clinicians in choosing specific drug doses to the spine or brain may help improve treatment schedules. Methods This study applied computational fluid dynamics (CFD) and in vitro model verification to assess intrathecal drug delivery in an anatomically idealized model of the human CSF system with key anatomic features of the CNS. Key parameters analyzed included the role of (a) injection location including lumbar puncture (LP), cisterna magna (CM) and intracerebroventricular (ICV), (b) LP injection rate, injection volume, and flush volume, (c) physiologic factors including cardiac-induced and deep respiration-induced CSF stroke volume increase. Simulations were conducted for 3-h post-injection and used to quantify spatial–temporal tracer concentration, regional area under the curve (AUC), time to maximum concentration (Tmax), and maximum concentration (Cmax), for each case. Results CM and ICV increased AUC to brain regions by ~ 2 logs compared to all other simulations. A 3X increase in bolus volume and addition of a 5 mL flush both increased intracranial AUC to the brain up to 2X compared to a baseline 5 mL LP injection. In contrast, a 5X increase in bolus rate (25 mL/min) did not improve tracer exposure to the brain. An increase in cardiac and respiratory CSF movement improved tracer spread to the brain, basal cistern, and cerebellum up to ~ 2 logs compared to the baseline LP injection. Conclusion The computational modeling approach provides ability to conduct in silico trials representative of CSF injection protocols. Taken together, the findings indicate a strong potential for delivery protocols to be optimized to reach a target region(s) of the spine and/or brain with a needed therapeutic dose. Parametric modification of bolus rate/volume and flush volume was found to have impact on tracer distribution; albeit to a smaller degree than injection location, with CM and ICV injections resulting in greater therapeutic dose to brain regions compared to LP. CSF stroke volume and frequency both played an important role and may potentially have a greater impact than the modest changes in LP injection protocols analyzed such as bolus rate, volume, and flush. Supplementary Information The online version contains supplementary material available at 10.1186/s12987-022-00304-4.
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15
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Sadekar SS, Bowen M, Cai H, Jamalian S, Rafidi H, Shatz‐Binder W, Lafrance‐Vanasse J, Chan P, Meilandt WJ, Oldendorp A, Sreedhara A, Daugherty A, Crowell S, Wildsmith KR, Atwal J, Fuji RN, Horvath J. Translational approaches for brain delivery of biologics via cerebrospinal fluid. Clin Pharmacol Ther 2022; 111:826-834. [PMID: 35064573 PMCID: PMC9305158 DOI: 10.1002/cpt.2531] [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: 09/21/2021] [Accepted: 01/04/2022] [Indexed: 11/14/2022]
Abstract
Delivery of biologics via cerebrospinal fluid (CSF) has demonstrated potential to access the tissues of the central nervous system (CNS) by circumventing the blood‐brain barrier and blood‐CSF barrier. Developing an effective CSF drug delivery strategy requires optimization of multiple parameters, including choice of CSF access point, delivery device technology, and delivery kinetics to achieve effective therapeutic concentrations in the target brain region, whereas also considering the biologic modality, mechanism of action, disease indication, and patient population. This review discusses key preclinical and clinical examples of CSF delivery for different biologic modalities (antibodies, nucleic acid‐based therapeutics, and gene therapy) to the brain via CSF or CNS access routes (intracerebroventricular, intrathecal‐cisterna magna, intrathecal‐lumbar, intraparenchymal, and intranasal), including the use of novel device technologies. This review also discusses quantitative models of CSF flow that provide insight into the effect of fluid dynamics in CSF on drug delivery and CNS distribution. Such models can facilitate delivery device design and pharmacokinetic/pharmacodynamic translation from preclinical species to humans in order to optimize CSF drug delivery to brain regions of interest.
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Affiliation(s)
- Shraddha S Sadekar
- Genentech Research and Early Development Genentech, Inc., a member of the Roche Group 1 DNA Way South San Francisco CA 94080 USA
| | - Mayumi Bowen
- Pharma Technical Development. Genentech, Inc, a member of the Roche Group 1 DNA Way South San Francisco CA 94080 USA
| | - Hao Cai
- Genentech Research and Early Development Genentech, Inc., a member of the Roche Group 1 DNA Way South San Francisco CA 94080 USA
| | - Samira Jamalian
- Genentech Research and Early Development Genentech, Inc., a member of the Roche Group 1 DNA Way South San Francisco CA 94080 USA
| | - Hanine Rafidi
- Genentech Research and Early Development Genentech, Inc., a member of the Roche Group 1 DNA Way South San Francisco CA 94080 USA
| | - Whitney Shatz‐Binder
- Genentech Research and Early Development Genentech, Inc., a member of the Roche Group 1 DNA Way South San Francisco CA 94080 USA
| | - Julien Lafrance‐Vanasse
- Genentech Research and Early Development Genentech, Inc., a member of the Roche Group 1 DNA Way South San Francisco CA 94080 USA
| | - Pamela Chan
- Genentech Research and Early Development Genentech, Inc., a member of the Roche Group 1 DNA Way South San Francisco CA 94080 USA
| | - William J. Meilandt
- Genentech Research and Early Development Genentech, Inc., a member of the Roche Group 1 DNA Way South San Francisco CA 94080 USA
| | - Amy Oldendorp
- Genentech Research and Early Development Genentech, Inc., a member of the Roche Group 1 DNA Way South San Francisco CA 94080 USA
| | - Alavattam Sreedhara
- Pharma Technical Development. Genentech, Inc, a member of the Roche Group 1 DNA Way South San Francisco CA 94080 USA
| | - Ann Daugherty
- Pharma Technical Development. Genentech, Inc, a member of the Roche Group 1 DNA Way South San Francisco CA 94080 USA
| | - Susan Crowell
- Genentech Research and Early Development Genentech, Inc., a member of the Roche Group 1 DNA Way South San Francisco CA 94080 USA
| | - Kristin R. Wildsmith
- Clinical pharmacology and translational medicine Neurology business Eisai, Nutley NJ 07110 USA
| | - Jasvinder Atwal
- Genentech Research and Early Development Genentech, Inc., a member of the Roche Group 1 DNA Way South San Francisco CA 94080 USA
| | - Reina N. Fuji
- Genentech Research and Early Development Genentech, Inc., a member of the Roche Group 1 DNA Way South San Francisco CA 94080 USA
| | - Josh Horvath
- Pharma Technical Development. Genentech, Inc, a member of the Roche Group 1 DNA Way South San Francisco CA 94080 USA
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16
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Zahid AM, Martin B, Collins S, Oshinski JN, Ethier CR. Quantification of arterial, venous, and cerebrospinal fluid flow dynamics by magnetic resonance imaging under simulated micro-gravity conditions: a prospective cohort study. Fluids Barriers CNS 2021; 18:8. [PMID: 33579319 PMCID: PMC7879666 DOI: 10.1186/s12987-021-00238-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 12/24/2020] [Accepted: 01/11/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Astronauts undergoing long-duration spaceflight are exposed to numerous health risks, including Spaceflight-Associated Neuro-Ocular Syndrome (SANS), a spectrum of ophthalmic changes that can result in permanent loss of visual acuity. The etiology of SANS is not well understood but is thought to involve changes in cerebrovascular flow dynamics in response to microgravity. There is a paucity of knowledge in this area; in particular, cerebrospinal fluid (CSF) flow dynamics have not been well characterized under microgravity conditions. Our study was designed to determine the effect of simulated microgravity (head-down tilt [HDT]) on cerebrovascular flow dynamics. We hypothesized that microgravity conditions simulated by acute HDT would result in increases in CSF pulsatile flow. METHODS In a prospective cohort study, we measured flow in major cerebral arteries, veins, and CSF spaces in fifteen healthy volunteers using phase contrast magnetic resonance (PCMR) before and during 15° HDT. RESULTS We found a decrease in all CSF flow variables [systolic peak flow (p = 0.009), and peak-to-peak pulse amplitude (p = 0.001)]. Cerebral arterial average flow (p = 0.04), systolic peak flow (p = 0.04), and peak-to-peak pulse amplitude (p = 0.02) all also significantly decreased. We additionally found a decrease in average cerebral arterial flow (p = 0.040). Finally, a significant increase in cerebral venous cross-sectional area under HDT (p = 0.005) was also observed. CONCLUSIONS These results collectively demonstrate that acute application of -15° HDT caused a reduction in CSF flow variables (systolic peak flow and peak-to-peak pulse amplitude) which, when coupled with a decrease in average cerebral arterial flow, systolic peak flow, and peak-to-peak pulse amplitude, is consistent with a decrease in cardiac-related pulsatile CSF flow. These results suggest that decreases in cerebral arterial inflow were the principal drivers of decreases in CSF pulsatile flow.
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Affiliation(s)
- Arslan M Zahid
- Emory University School of Medicine, Atlanta, GA, USA. .,University of Chicago, 900 S Clark Street, Apt 1001, Chicago, IL, 60605, USA.
| | - Bryn Martin
- Department of Biological Engineering, University of Idaho, Moscow, Idaho, USA.,Alycone Therapeutics, Lowell, MA, USA
| | - Stephanie Collins
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA, USA
| | - John N Oshinski
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA, USA.,Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, USA
| | - C Ross Ethier
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA, USA
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17
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Khani M, Fu AQ, Pluid J, Gibbs CP, Oshinski JN, Xing T, Stewart GR, Zeller JR, Martin BA. Intrathecal catheter implantation decreases cerebrospinal fluid dynamics in cynomolgus monkeys. PLoS One 2020; 15:e0244090. [PMID: 33378399 PMCID: PMC7773283 DOI: 10.1371/journal.pone.0244090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 12/02/2020] [Indexed: 11/23/2022] Open
Abstract
A detailed understanding of the CSF dynamics is needed for design and optimization of intrathecal drug delivery devices, drugs, and protocols. Preclinical research using large-animal models is important to help define drug pharmacokinetics-pharmacodynamics and safety. In this study, we investigated the impact of catheter implantation in the sub-dural space on CSF flow dynamics in Cynomolgus monkeys. Magnetic resonance imaging (MRI) was performed before and after catheter implantation to quantify the differences based on catheter placement location in the cervical compared to the lumbar spine. Several geometric and hydrodynamic parameters were calculated based on the 3D segmentation and flow analysis. Hagen-Poiseuille equation was used to investigate the impact of catheter implantation on flow reduction and hydraulic resistance. A linear mixed-effects model was used in this study to investigate if there was a statistically significant difference between cervical and lumbar implantation, or between two MRI time points. Results showed that geometric parameters did not change statistically across MRI measurement time points and did not depend on catheter location. However, catheter insertion did have a significant impact on the hydrodynamic parameters and the effect was greater with cervical implantation compared to lumbar implantation. CSF flow rate decreased up to 55% with the catheter located in the cervical region. The maximum flow rate reduction in the lumbar implantation group was 21%. Overall, lumbar catheter implantation disrupted CSF dynamics to a lesser degree than cervical catheter implantation and this effect remained up to two weeks post-catheter implantation in Cynomolgus monkeys.
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Affiliation(s)
- Mohammadreza Khani
- Department of Chemical and Biological Engineering, University of Idaho, Moscow, ID, United States of America
- Alcyone Therapeutics, Lowell, MA, United States of America
| | - Audrey Q. Fu
- Department of Statistical Science, University of Idaho, Moscow, ID, United States of America
| | - Joshua Pluid
- Department of Chemical and Biological Engineering, University of Idaho, Moscow, ID, United States of America
| | - Christina P. Gibbs
- Department of Chemical and Biological Engineering, University of Idaho, Moscow, ID, United States of America
| | - John N. Oshinski
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, United States of America
| | - Tao Xing
- Department of Mechanical Engineering, University of Idaho, Moscow, ID, United States of America
| | - Gregory R. Stewart
- Alcyone Therapeutics, Lowell, MA, United States of America
- Voyager Therapeutics, Cambridge, MA, United States of America
| | | | - Bryn A. Martin
- Department of Chemical and Biological Engineering, University of Idaho, Moscow, ID, United States of America
- Alcyone Therapeutics, Lowell, MA, United States of America
- * E-mail:
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18
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Bordoni B, Walkowski S, Ducoux B, Tobbi F. The Cranial Bowl in the New Millennium and Sutherland's Legacy for Osteopathic Medicine: Part 2. Cureus 2020; 12:e10435. [PMID: 33062548 PMCID: PMC7556686 DOI: 10.7759/cureus.10435] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Cranial osteopathic medicine is practiced all over the world, respecting the dictates of the creator, Dr Sutherland. Despite the current manual approach faithfully follows the theoretical and practical bases that make up the cranial model of the last century, there are many scientific evidences that highlight the criticalities of the same model. In the first part we reviewed the role of the meninges and cerebrospinal fluid (CSF), as well as we discussed some rhythms present in the central nervous system; these latter elements are the pillars to support the theoretical idea of the movement of the skull evaluated and palpated by the osteopath. In this second part we will review the mechanical characteristics of other structures that make up the cranial system, highlighting new perspectives for clinical practice, thanks to the most recent data derived from scientific research.
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Affiliation(s)
- Bruno Bordoni
- Physical Medicine and Rehabilitation, Foundation Don Carlo Gnocchi, Milan, ITA
| | - Stevan Walkowski
- Osteopathic Manipulative Medicine, Heritage College of Osteopathic Medicine-Dublin, Dublin, USA
| | - Bruno Ducoux
- Osteopathy, Formation Recherche Osteopathie Prévention, Bordeaux, FRA
| | - Filippo Tobbi
- Osteopathy, Poliambulatorio Medico e Odontoiatrico, Varese, ITA
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19
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Donatelli D, Romagnoli L. Nonreflecting Boundary Conditions for a CSF Model of Fourth Ventricle: Spinal SAS Dynamics. Bull Math Biol 2020; 82:77. [PMID: 32535866 DOI: 10.1007/s11538-020-00749-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 05/15/2020] [Indexed: 11/24/2022]
Abstract
In this paper, we introduce a one-dimensional model for analyzing the cerebrospinal fluid dynamics within the fourth ventricle and the spinal subarachnoid space (SSAS). The model has been derived starting from an original model of Linninger et al. and from the detailed mathematical analysis of two different reformulations. We show the steps of the modelization and the rigorous analysis of the first-order nonlinear hyperbolic system of equations which rules the new CSF model, whose conservative-law form and characteristic form are required for the boundary conditions treatment. By assuming sub-critical flows, for the particular dynamics we are dealing with, the most desirable option is to employ the nonreflecting boundary conditions, that allow the simple wave associated with the outgoing characteristic to exit the computational domain with no reflections. Finally, we carry out some numerical simulations related to different cerebral physiological conditions.
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Affiliation(s)
- Donatella Donatelli
- Department of Information Engineering, Computer Science and Mathematics, University of L'Aquila, 67100, L'Aquila, Italy.
| | - Licia Romagnoli
- Department of Information Engineering, Computer Science and Mathematics, University of L'Aquila, 67100, L'Aquila, Italy
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20
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Khani M, Sass LR, Sharp MK, McCabe AR, Zitella Verbick LM, Lad SP, Martin BA. In vitro and numerical simulation of blood removal from cerebrospinal fluid: comparison of lumbar drain to Neurapheresis therapy. Fluids Barriers CNS 2020; 17:23. [PMID: 32178689 PMCID: PMC7077023 DOI: 10.1186/s12987-020-00185-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 03/06/2020] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Blood removal from cerebrospinal fluid (CSF) in post-subarachnoid hemorrhage patients may reduce the risk of related secondary brain injury. We formulated a computational fluid dynamics (CFD) model to investigate the impact of a dual-lumen catheter-based CSF filtration system, called Neurapheresis™ therapy, on blood removal from CSF compared to lumbar drain. METHODS A subject-specific multiphase CFD model of CSF system-wide solute transport was constructed based on MRI measurements. The Neurapheresis catheter geometry was added to the model within the spinal subarachnoid space (SAS). Neurapheresis flow aspiration and return rate was 2.0 and 1.8 mL/min, versus 0.2 mL/min drainage for lumbar drain. Blood was modeled as a bulk fluid phase within CSF with a 10% initial tracer concentration and identical viscosity and density as CSF. Subject-specific oscillatory CSF flow was applied at the model inlet. The dura and spinal cord geometry were considered to be stationary. Spatial-temporal tracer concentration was quantified based on time-average steady-streaming velocities throughout the domain under Neurapheresis therapy and lumbar drain. To help verify CFD results, an optically clear in vitro CSF model was constructed with fluorescein used as a blood surrogate. Quantitative comparison of numerical and in vitro results was performed by linear regression of spatial-temporal tracer concentration over 24-h. RESULTS After 24-h, tracer concentration was reduced to 4.9% under Neurapheresis therapy compared to 6.5% under lumbar drain. Tracer clearance was most rapid between the catheter aspiration and return ports. Neurapheresis therapy was found to have a greater impact on steady-streaming compared to lumbar drain. Steady-streaming in the cranial SAS was ~ 50× smaller than in the spinal SAS for both cases. CFD results were strongly correlated with the in vitro spatial-temporal tracer concentration under Neurapheresis therapy (R2 = 0.89 with + 2.13% and - 1.93% tracer concentration confidence interval). CONCLUSION A subject-specific CFD model of CSF system-wide solute transport was used to investigate the impact of Neurapheresis therapy on tracer removal from CSF compared to lumbar drain over a 24-h period. Neurapheresis therapy was found to substantially increase tracer clearance compared to lumbar drain. The multiphase CFD results were verified by in vitro fluorescein tracer experiments.
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Affiliation(s)
- Mohammadreza Khani
- Department of Biological Engineering, The University of Idaho, 875 Perimeter Drive, MS 0904, Moscow, ID, 83844-0904, USA
| | - Lucas R Sass
- Department of Biological Engineering, The University of Idaho, 875 Perimeter Drive, MS 0904, Moscow, ID, 83844-0904, USA
| | - M Keith Sharp
- Department of Mechanical Engineering, University of Louisville, 332 Eastern Pkwy, Louisville, KY, 40292, USA
| | - Aaron R McCabe
- Minnetronix Neuro, Inc., 1635 Energy Park Dr, Saint Paul, MN, 55108, USA
| | | | - Shivanand P Lad
- Department of Neurosurgery, Duke University School of Medicine, 3100 Tower Blvd, Durham, NC, 27707, USA
| | - Bryn A Martin
- Department of Biological Engineering, The University of Idaho, 875 Perimeter Drive, MS 0904, Moscow, ID, 83844-0904, USA.
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21
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Jones HC, Keep RF, Drewes LR. CNS fluid and solute movement: physiology, modelling and imaging. Fluids Barriers CNS 2020; 17:12. [PMID: 32019555 PMCID: PMC6998813 DOI: 10.1186/s12987-020-0174-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Hazel C Jones
- Gagle Brook House, Chesterton, Bicester, OX26 1UF, UK.
| | - Richard F Keep
- Department of Neurosurgery, University of Michigan, Ann Arbor, MI, 48105, USA
| | - Lester R Drewes
- Department of Biomedical Sciences, University of Minnesota Medical School Duluth, Duluth, MN, 55812, USA
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22
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Khani M, Sass LR, McCabe AR, Zitella Verbick LM, Lad SP, Sharp MK, Martin BA. Impact of Neurapheresis System on Intrathecal Cerebrospinal Fluid Dynamics: A Computational Fluid Dynamics Study. J Biomech Eng 2020; 142:021006. [PMID: 31343659 PMCID: PMC7104775 DOI: 10.1115/1.4044308] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 07/18/2019] [Indexed: 11/08/2022]
Abstract
It has been hypothesized that early and rapid filtration of blood from cerebrospinal fluid (CSF) in postsubarachnoid hemorrhage patients may reduce hospital stay and related adverse events. In this study, we formulated a subject-specific computational fluid dynamics (CFD) model to parametrically investigate the impact of a novel dual-lumen catheter-based CSF filtration system, the Neurapheresis™ system (Minnetronix Neuro, Inc., St. Paul, MN), on intrathecal CSF dynamics. The operating principle of this system is to remove CSF from one location along the spine (aspiration port), externally filter the CSF routing the retentate to a waste bag, and return permeate (uncontaminated CSF) to another location along the spine (return port). The CFD model allowed parametric simulation of how the Neurapheresis system impacts intrathecal CSF velocities and steady-steady streaming under various Neurapheresis flow settings ranging from 0.5 to 2.0 ml/min and with a constant retentate removal rate of 0.2 ml/min simulation of the Neurapheresis system were compared to a lumbar drain simulation with a typical CSF removal rate setting of 0.2 ml/min. Results showed that the Neurapheresis system at a maximum flow of 2.0 ml/min increased average steady streaming CSF velocity 2× in comparison to lumbar drain (0.190 ± 0.133 versus 0.093 ± 0.107 mm/s, respectively). This affect was localized to the region within the Neurapheresis flow loop. The mean velocities introduced by the flow loop were relatively small in comparison to normal cardiac-induced CSF velocities.
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Affiliation(s)
- Mohammadreza Khani
- Department of Biological Engineering, University of Idaho, Moscow, ID 83844
| | - Lucas R. Sass
- Department of Biological Engineering, University of Idaho, Moscow, ID 83844
| | | | | | - Shivanand P. Lad
- Department of Neurosurgery, Duke University School of Medicine, Durham, NC 27710
| | - M. Keith Sharp
- Department of Mechanical Engineering, University of Louisville, Louisville, KY 40292
| | - Bryn A. Martin
- Department of Biological Engineering, University of Idaho, Moscow, ID 83844
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23
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Sass LR, Khani M, Romm J, Schmid Daners M, McCain K, Freeman T, Carter GT, Weeks DL, Petersen B, Aldred J, Wingett D, Martin BA. Non-invasive MRI quantification of cerebrospinal fluid dynamics in amyotrophic lateral sclerosis patients. Fluids Barriers CNS 2020; 17:4. [PMID: 31959193 PMCID: PMC6971921 DOI: 10.1186/s12987-019-0164-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 12/19/2019] [Indexed: 02/07/2023] Open
Abstract
Background Developing novel therapeutic agents to treat amyotrophic lateral sclerosis (ALS) has been difficult due to multifactorial pathophysiologic processes at work. Intrathecal drug administration shows promise due to close proximity of cerebrospinal fluid (CSF) to affected tissues. Development of effective intrathecal pharmaceuticals will rely on accurate models of how drugs are dispersed in the CSF. Therefore, a method to quantify these dynamics and a characterization of differences across disease states is needed. Methods Complete intrathecal 3D CSF geometry and CSF flow velocities at six axial locations in the spinal canal were collected by T2-weighted and phase-contrast MRI, respectively. Scans were completed for eight people with ALS and ten healthy controls. Manual segmentation of the spinal subarachnoid space was performed and coupled with an interpolated model of CSF flow within the spinal canal. Geometric and hydrodynamic parameters were then generated at 1 mm slice intervals along the entire spine. Temporal analysis of the waveform spectral content and feature points was also completed. Results Comparison of ALS and control groups revealed a reduction in CSF flow magnitude and increased flow propagation velocities in the ALS cohort. Other differences in spectral harmonic content and geometric comparisons may support an overall decrease in intrathecal compliance in the ALS group. Notably, there was a high degree of variability between cases, with one ALS patient displaying nearly zero CSF flow along the entire spinal canal. Conclusion While our sample size limits statistical confidence about the differences observed in this study, it was possible to measure and quantify inter-individual and cohort variability in a non-invasive manner. Our study also shows the potential for MRI based measurements of CSF geometry and flow to provide information about the hydrodynamic environment of the spinal subarachnoid space. These dynamics may be studied further to understand the behavior of CSF solute transport in healthy and diseased states.
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Affiliation(s)
- Lucas R Sass
- Neurophysiological Imaging and Modeling Laboratory, University of Idaho, 875 Perimeter Dr. MS1122, Moscow, ID, 83844, USA
| | - Mohammadreza Khani
- Neurophysiological Imaging and Modeling Laboratory, University of Idaho, 875 Perimeter Dr. MS1122, Moscow, ID, 83844, USA
| | - Jacob Romm
- Neurophysiological Imaging and Modeling Laboratory, University of Idaho, 875 Perimeter Dr. MS1122, Moscow, ID, 83844, USA.,University of Washington School of Medicine, 1959 NE Pacific St, Seattle, WA, 98195, USA
| | - Marianne Schmid Daners
- Product Development Group Zurich, Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland
| | - Kyle McCain
- Neurophysiological Imaging and Modeling Laboratory, University of Idaho, 875 Perimeter Dr. MS1122, Moscow, ID, 83844, USA
| | - Tavara Freeman
- Neurophysiological Imaging and Modeling Laboratory, University of Idaho, 875 Perimeter Dr. MS1122, Moscow, ID, 83844, USA
| | - Gregory T Carter
- St. Luke's Rehabilitation Institute, 711 South Cowley St., Spokane, WA, 99202, USA
| | - Douglas L Weeks
- St. Luke's Rehabilitation Institute, 711 South Cowley St., Spokane, WA, 99202, USA
| | - Brian Petersen
- Inland Imaging PS and LLC, 801 South Stevens St., Spokane, WA, 99204, USA
| | - Jason Aldred
- Selkirk Neurology, 610 South Sherman St. #201, Spokane, WA, 99202, USA
| | - Dena Wingett
- Inland Imaging LLC, 801 South Stevens St., Spokane, WA, 99204, USA
| | - Bryn A Martin
- Neurophysiological Imaging and Modeling Laboratory, University of Idaho, 875 Perimeter Dr. MS1122, Moscow, ID, 83844, USA. .,Biological Engineering, University of Idaho, 875 Perimeter Dr. MS0904, Moscow, ID, 83844-0904, USA.
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24
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Khani M, Sass LR, Xing T, Keith Sharp M, Balédent O, Martin BA. Anthropomorphic Model of Intrathecal Cerebrospinal Fluid Dynamics Within the Spinal Subarachnoid Space: Spinal Cord Nerve Roots Increase Steady-Streaming. J Biomech Eng 2019; 140:2683234. [PMID: 30003260 DOI: 10.1115/1.4040401] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Indexed: 11/08/2022]
Abstract
Cerebrospinal fluid (CSF) dynamics are thought to play a vital role in central nervous system (CNS) physiology. The objective of this study was to investigate the impact of spinal cord (SC) nerve roots (NR) on CSF dynamics. A subject-specific computational fluid dynamics (CFD) model of the complete spinal subarachnoid space (SSS) with and without anatomically realistic NR and nonuniform moving dura wall deformation was constructed. This CFD model allowed detailed investigation of the impact of NR on CSF velocities that is not possible in vivo using magnetic resonance imaging (MRI) or other noninvasive imaging methods. Results showed that NR altered CSF dynamics in terms of velocity field, steady-streaming, and vortical structures. Vortices occurred in the cervical spine around NR during CSF flow reversal. The magnitude of steady-streaming CSF flow increased with NR, in particular within the cervical spine. This increase was located axially upstream and downstream of NR due to the interface of adjacent vortices that formed around NR.
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Affiliation(s)
- Mohammadreza Khani
- Neurophysiological Imaging and Modeling Laboratory, Department of Biological Engineering, University of Idaho, Moscow, ID 83844 e-mail:
| | - Lucas R Sass
- Neurophysiological Imaging and Modeling Laboratory, Department of Biological Engineering, University of Idaho, Moscow, ID 83844 e-mail:
| | - Tao Xing
- Department of Mechanical Engineering, University of Idaho, Moscow, ID 83844 e-mail:
| | - M Keith Sharp
- Biofluid Mechanics Laboratory, University of Louisville, Louisville, KY 40292 e-mail:
| | - Olivier Balédent
- Bioflow Image, CHU Nord Amiens-Picardie, Amiens 80054, France e-mail:
| | - Bryn A Martin
- Neurophysiological Imaging and Modeling Laboratory, Department of Biological Engineering, University of Idaho, Moscow, ID 83844 e-mail:
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25
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Vendel E, Rottschäfer V, de Lange ECM. The need for mathematical modelling of spatial drug distribution within the brain. Fluids Barriers CNS 2019; 16:12. [PMID: 31092261 PMCID: PMC6521438 DOI: 10.1186/s12987-019-0133-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 04/19/2019] [Indexed: 12/17/2022] Open
Abstract
The blood brain barrier (BBB) is the main barrier that separates the blood from the brain. Because of the BBB, the drug concentration-time profile in the brain may be substantially different from that in the blood. Within the brain, the drug is subject to distributional and elimination processes: diffusion, bulk flow of the brain extracellular fluid (ECF), extra-intracellular exchange, bulk flow of the cerebrospinal fluid (CSF), binding and metabolism. Drug effects are driven by the concentration of a drug at the site of its target and by drug-target interactions. Therefore, a quantitative understanding is needed of the distribution of a drug within the brain in order to predict its effect. Mathematical models can help in the understanding of drug distribution within the brain. The aim of this review is to provide a comprehensive overview of system-specific and drug-specific properties that affect the local distribution of drugs in the brain and of currently existing mathematical models that describe local drug distribution within the brain. Furthermore, we provide an overview on which processes have been addressed in these models and which have not. Altogether, we conclude that there is a need for a more comprehensive and integrated model that fills the current gaps in predicting the local drug distribution within the brain.
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Affiliation(s)
- Esmée Vendel
- Mathematical Institute, Leiden University, Niels Bohrweg 1, 2333CA, Leiden, The Netherlands
| | - Vivi Rottschäfer
- Mathematical Institute, Leiden University, Niels Bohrweg 1, 2333CA, Leiden, The Netherlands
| | - Elizabeth C M de Lange
- Leiden Academic Centre for Drug Research, Einsteinweg 55, 2333CC, Leiden, The Netherlands.
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26
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Keith Sharp M, Carare RO, Martin BA. Dispersion in porous media in oscillatory flow between flat plates: applications to intrathecal, periarterial and paraarterial solute transport in the central nervous system. Fluids Barriers CNS 2019; 16:13. [PMID: 31056079 PMCID: PMC6512764 DOI: 10.1186/s12987-019-0132-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 04/16/2019] [Indexed: 01/22/2023] Open
Abstract
Background As an alternative to advection, solute transport by shear-augmented dispersion within oscillatory cerebrospinal fluid flow was investigated in small channels representing the basement membranes located between cerebral arterial smooth muscle cells, the paraarterial space surrounding the vessel wall and in large channels modeling the spinal subarachnoid space (SSS). Methods Geometries were modeled as two-dimensional. Fully developed flows in the channels were modeled by the Darcy–Brinkman momentum equation and dispersion by the passive transport equation. Scaling of the enhancement of axial dispersion relative to molecular diffusion was developed for regimes of flow including quasi-steady, porous and unsteady, and for regimes of dispersion including diffusive and unsteady. Results Maximum enhancement occurs when the characteristic time for lateral dispersion is matched to the cycle period. The Darcy–Brinkman model represents the porous media as a continuous flow resistance, and also imposes no-slip boundary conditions at the walls of the channel. Consequently, predicted dispersion is always reduced relative to that of a channel without porous media, except when the flow and dispersion are both unsteady. Discussion/conclusions In the basement membranes, flow and dispersion are both quasi-steady and enhancement of dispersion is small even if lateral dispersion is reduced by the porous media to achieve maximum enhancement. In the paraarterial space, maximum enhancement Rmax = 73,200 has the potential to be significant. In the SSS, the dispersion is unsteady and the flow is in the transition zone between porous and unsteady. Enhancement is 5.8 times that of molecular diffusion, and grows to a maximum of 1.6E+6 when lateral dispersion is increased. The maximum enhancement produces rostral transport time in agreement with experiments. Electronic supplementary material The online version of this article (10.1186/s12987-019-0132-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- M Keith Sharp
- Biofluid Mechanics Laboratory, Department of Mechanical Engineering, University of Louisville, Louisville, KY, 40292, USA.
| | - Roxana O Carare
- Faculty of Medicine, Southampton General Hospital, University of Southampton, Southampton, SO16 6YD, UK
| | - Bryn A Martin
- Department of Biological Engineering, University of Idaho, Moscow, ID, 83844, USA
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27
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Khani M, Lawrence BJ, Sass LR, Gibbs CP, Pluid JJ, Oshinski JN, Stewart GR, Zeller JR, Martin BA. Characterization of intrathecal cerebrospinal fluid geometry and dynamics in cynomolgus monkeys (macaca fascicularis) by magnetic resonance imaging. PLoS One 2019; 14:e0212239. [PMID: 30811449 PMCID: PMC6392269 DOI: 10.1371/journal.pone.0212239] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 01/29/2019] [Indexed: 02/08/2023] Open
Abstract
Recent advancements have been made toward understanding the diagnostic and therapeutic potential of cerebrospinal fluid (CSF) and related hydrodynamics. Increased understanding of CSF dynamics may lead to improved detection of central nervous system (CNS) diseases and optimized delivery of CSF based CNS therapeutics, with many proposed therapeutics hoping to successfully treat or cure debilitating neurological conditions. Before significant strides can be made toward the research and development of interventions designed for human use, additional research must be carried out with representative subjects such as non-human primates (NHP). This study presents a geometric and hydrodynamic characterization of CSF in eight cynomolgus monkeys (Macaca fascicularis) at baseline and two-week follow-up. Results showed that CSF flow along the entire spine was laminar with a Reynolds number ranging up to 80 and average Womersley number ranging from 4.1–7.7. Maximum CSF flow rate occurred ~25 mm caudal to the foramen magnum. Peak CSF flow rate ranged from 0.3–0.6 ml/s at the C3-C4 level. Geometric analysis indicated that average intrathecal CSF volume below the foramen magnum was 7.4 ml. The average surface area of the spinal cord and dura was 44.7 and 66.7 cm2 respectively. Subarachnoid space cross-sectional area and hydraulic diameter ranged from 7–75 mm2 and 2–3.7 mm, respectively. Stroke volume had the greatest value of 0.14 ml at an axial location corresponding to C3-C4.
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Affiliation(s)
- Mohammadreza Khani
- Department of Biological Engineering, University of Idaho, Moscow, ID, United States of America
| | - Braden J. Lawrence
- Department of Biological Engineering, University of Idaho, Moscow, ID, United States of America
- School of Medicine, University of Washington, Seattle, WA, United States of America
| | - Lucas R. Sass
- Department of Biological Engineering, University of Idaho, Moscow, ID, United States of America
| | - Christina P. Gibbs
- Department of Biological Engineering, University of Idaho, Moscow, ID, United States of America
| | - Joshua J. Pluid
- Department of Biological Engineering, University of Idaho, Moscow, ID, United States of America
| | - John N. Oshinski
- Department of Radiology, Emory University, Atlanta, GA, United States of America
| | - Gregory R. Stewart
- Axovant, New York, NY, United States of America
- Voyager Therapeutics, Cambridge, MA, United States of America
| | | | - Bryn A. Martin
- Department of Biological Engineering, University of Idaho, Moscow, ID, United States of America
- * E-mail:
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