1
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Gao Z. Strategies for enhanced gene delivery to the central nervous system. NANOSCALE ADVANCES 2024; 6:3009-3028. [PMID: 38868835 PMCID: PMC11166101 DOI: 10.1039/d3na01125a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Accepted: 04/12/2024] [Indexed: 06/14/2024]
Abstract
The delivery of genes to the central nervous system (CNS) has been a persistent challenge due to various biological barriers. The blood-brain barrier (BBB), in particular, hampers the access of systemically injected drugs to parenchymal cells, allowing only a minimal percentage (<1%) to pass through. Recent scientific insights highlight the crucial role of the extracellular space (ECS) in governing drug diffusion. Taking into account advancements in vectors, techniques, and knowledge, the discussion will center on the most notable vectors utilized for gene delivery to the CNS. This review will explore the influence of the ECS - a dynamically regulated barrier-on drug diffusion. Furthermore, we will underscore the significance of employing remote-control technologies to facilitate BBB traversal and modulate the ECS. Given the rapid progress in gene editing, our discussion will also encompass the latest advances focused on delivering therapeutic editing in vivo to the CNS tissue. In the end, a brief summary on the impact of Artificial Intelligence (AI)/Machine Learning (ML), ultrasmall, soft endovascular robots, and high-resolution endovascular cameras on improving the gene delivery to the CNS will be provided.
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Affiliation(s)
- Zhenghong Gao
- Mechanical Engineering, The University of Texas at Dallas USA
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2
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Xu R, Bestmann S, Treeby BE, Martin E. Strategies and safety simulations for ultrasonic cervical spinal cord neuromodulation. Phys Med Biol 2024; 69:125011. [PMID: 38788727 DOI: 10.1088/1361-6560/ad506f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 05/24/2024] [Indexed: 05/26/2024]
Abstract
Objective. Focused ultrasound spinal cord neuromodulation has been demonstrated in small animals. However, most of the tested neuromodulatory exposures are similar in intensity and exposure duration to the reported small animal threshold for possible spinal cord damage. All efforts must be made to minimize the risk and assure the safety of potential human studies, while maximizing potential treatment efficacy. This requires an understanding of ultrasound propagation and heat deposition within the human spine.Approach. Combined acoustic and thermal modelling was used to assess the pressure and heat distributions produced by a 500 kHz source focused to the C5/C6 level via two approaches (a) the posterior acoustic window between vertebral posterior arches, and (b) the lateral intervertebral foramen from which the C6 spinal nerve exits. Pulse trains of fifty 0.1 s pulses (pulse repetition frequency: 0.33 Hz, free-field spatial peak pulse-averaged intensity: 10 W cm-2) were simulated for four subjects and for ±10 mm translational and ±10∘rotational source positioning errors.Main results.Target pressures ranged between 20%-70% of free-field spatial peak pressures with the posterior approach, and 20%-100% with the lateral approach. When the posterior source was optimally positioned, peak spine heating values were below 1 ∘C, but source mispositioning resulted in bone heating up to 4 ∘C. Heating with the lateral approach did not exceed 2 ∘C within the mispositioning range. There were substantial inter-subject differences in target pressures and peak heating values. Target pressure varied three to four-fold between subjects, depending on approach, while peak heating varied approximately two-fold between subjects. This results in a nearly ten-fold range between subjects in the target pressure achieved per degree of maximum heating.Significance. This study highlights the utility of trans-spine ultrasound simulation software and need for precise source-anatomy positioning to assure the subject-specific safety and efficacy of focused ultrasound spinal cord therapies.
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Affiliation(s)
- Rui Xu
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, London, United Kingdom
| | - Sven Bestmann
- Department of Clinical and Movement Neuroscience, University College London, London, United Kingdom
| | - Bradley E Treeby
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Eleanor Martin
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, London, United Kingdom
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3
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Song W, Jayaprakash N, Saleknezhad N, Puleo C, Al-Abed Y, Martin JH, Zanos S. Transspinal Focused Ultrasound Suppresses Spinal Reflexes in Healthy Rats. Neuromodulation 2024; 27:614-624. [PMID: 37530695 DOI: 10.1016/j.neurom.2023.04.476] [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: 07/19/2022] [Revised: 04/26/2023] [Accepted: 04/29/2023] [Indexed: 08/03/2023]
Abstract
OBJECTIVES Low-intensity, focused ultrasound (FUS) is an emerging noninvasive neuromodulation approach, with improved spatial and temporal resolution and penetration depth compared to other noninvasive electrical stimulation strategies. FUS has been used to modulate circuits in the brain and the peripheral nervous system, however, its potential to modulate spinal circuits is unclear. In this study, we assessed the effect of trans-spinal FUS (tsFUS) on spinal reflexes in healthy rats. MATERIALS AND METHODS tsFUS targeting different spinal segments was delivered for 1 minute, under anesthesia. Monosynaptic H-reflex of the sciatic nerve, polysynaptic flexor reflex of the sural nerve, and withdrawal reflex tested with a hot plate were measured before, during, and after tsFUS. RESULTS tsFUS reversibly suppresses the H-reflex in a spinal segment-, acoustic pressure- and pulse-repetition frequency (PRF)-dependent manner. tsFUS with high PRF augments the degree of homosynaptic depression of the H-reflex observed with paired stimuli. It suppresses the windup of components of the flexor reflex associated with slower, C-afferent, but not faster, A- afferent fibers. Finally, it increases the latency of the withdrawal reflex. tsFUS does not elicit neuronal loss in the spinal cord. CONCLUSIONS Our study provides evidence that tsFUS reversibly suppresses spinal reflexes and suggests that tsFUS could be a safe and effective strategy for spinal cord neuromodulation in disorders associated with hyperreflexia, including spasticity after spinal cord injury and painful syndromes.
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Affiliation(s)
- Weiguo Song
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Naveen Jayaprakash
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Nafiseh Saleknezhad
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Chris Puleo
- General Electric Research, Niskayuna, NY, USA
| | - Yousef Al-Abed
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - John H Martin
- Department of Molecular, Cellular, and Biomedical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, USA
| | - Stavros Zanos
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, USA; Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY; Elmezzi Graduate School of Molecular Medicine, Manhasset, NY.
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4
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Perolina E, Meissner S, Raos B, Harland B, Thakur S, Svirskis D. Translating ultrasound-mediated drug delivery technologies for CNS applications. Adv Drug Deliv Rev 2024; 208:115274. [PMID: 38452815 DOI: 10.1016/j.addr.2024.115274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 02/18/2024] [Accepted: 03/01/2024] [Indexed: 03/09/2024]
Abstract
Ultrasound enhances drug delivery into the central nervous system (CNS) by opening barriers between the blood and CNS and by triggering release of drugs from carriers. A key challenge in translating setups from in vitro to in vivo settings is achieving equivalent acoustic energy delivery. Multiple devices have now been demonstrated to focus ultrasound to the brain, with concepts emerging to also target the spinal cord. Clinical trials to date have used ultrasound to facilitate the opening of the blood-brain barrier. While most have focused on feasibility and safety considerations, therapeutic benefits are beginning to emerge. To advance translation of these technologies for CNS applications, researchers should standardise exposure protocol and fine-tune ultrasound parameters. Computational modelling should be increasingly used as a core component to develop both in vitro and in vivo setups for delivering accurate and reproducible ultrasound to the CNS. This field holds promise for transformative advancements in the management and pharmacological treatment of complex and challenging CNS disorders.
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Affiliation(s)
- Ederlyn Perolina
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Auckland 1023, New Zealand
| | - Svenja Meissner
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Auckland 1023, New Zealand
| | - Brad Raos
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Auckland 1023, New Zealand
| | - Bruce Harland
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Auckland 1023, New Zealand
| | - Sachin Thakur
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Auckland 1023, New Zealand
| | - Darren Svirskis
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Auckland 1023, New Zealand.
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5
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Xu R, Treeby BE, Martin E. Safety Review of Therapeutic Ultrasound for Spinal Cord Neuromodulation and Blood-Spinal Cord Barrier Opening. ULTRASOUND IN MEDICINE & BIOLOGY 2024; 50:317-331. [PMID: 38182491 DOI: 10.1016/j.ultrasmedbio.2023.11.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 11/07/2023] [Accepted: 11/10/2023] [Indexed: 01/07/2024]
Abstract
New focused ultrasound spinal cord applications have emerged, particularly those improving therapeutic agent delivery to the spinal cord via blood-spinal cord barrier opening and the neuromodulation of spinal cord tracts. One hurdle in the development of these applications is safety. It may be possible to use safety trends from seminal and subsequent works in focused ultrasound to guide the development of safety guidelines for spinal cord applications. We collated data from decades of pre-clinical studies and illustrate a clear relationship between damage, time-averaged spatial peak intensity and exposure duration. This relationship suggests a thermal mechanism underlies ultrasound-induced spinal cord damage. We developed minimum and mean thresholds for damage from these pre-clinical studies. When these thresholds were plotted against the parameters used in recent pre-clinical ultrasonic spinal cord neuromodulation studies, the majority of the neuromodulation studies were near or above the minimum threshold. This suggests that a thermal neuromodulatory effect may exist for ultrasonic spinal cord neuromodulation, and that the thermal dose must be carefully controlled to avoid damage to the spinal cord. By contrast, the intensity-exposure duration threshold had no predictive value when applied to blood-spinal cord barrier opening studies that employed injected contrast agents. Most blood-spinal cord barrier opening studies observed slight to severe damage, except for small animal studies that employed an active feedback control method to limit pressures based on measured bubble oscillation behavior. The development of new focused ultrasound spinal cord applications perhaps reflects the recent success in the development of focused ultrasound brain applications, and recent work has begun on the translation of these technologies from brain to spinal cord. However, a great deal of work remains to be done, particularly with respect to developing and accepting safety standards for these applications.
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Affiliation(s)
- Rui Xu
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK.
| | - Bradley E Treeby
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - Eleanor Martin
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK
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6
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Nouraein S, Lee S, Saenz VA, Del Mundo HC, Yiu J, Szablowski JO. Acoustically targeted noninvasive gene therapy in large brain volumes. Gene Ther 2024; 31:85-94. [PMID: 37696982 DOI: 10.1038/s41434-023-00421-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 08/23/2023] [Accepted: 08/31/2023] [Indexed: 09/13/2023]
Abstract
Focused Ultrasound Blood-Brain Barrier Opening (FUS-BBBO) can deliver adeno-associated viral vectors (AAVs) to treat genetic disorders of the brain. However, such disorders often affect large brain regions. Moreover, the applicability of FUS-BBBO in the treatment of brain-wide genetic disorders has not yet been evaluated. Herein, we evaluated the transduction efficiency and safety of opening up to 105 sites simultaneously. Increasing the number of targeted sites increased gene delivery efficiency at each site. We achieved transduction of up to 60% of brain cells with comparable efficiency in the majority of the brain regions. Furthermore, gene delivery with FUS-BBBO was safe even when all 105 sites were targeted simultaneously without negative effects on animal weight or neuronal loss. To evaluate the application of multi-site FUS-BBBO for gene therapy, we used it for gene editing using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (Cas9) system and found effective gene editing, but also a loss of neurons at the targeted sites. Overall, this study provides a brain-wide map of transduction efficiency, shows the synergistic effect of multi-site targeting on transduction efficiency, and is the first example of large brain volume gene editing after noninvasive gene delivery with FUS-BBBO.
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Affiliation(s)
- Shirin Nouraein
- Department of Bioengineering, Rice University, Houston, TX, 77030, USA
- Rice Neuroengineering Initiative, Rice University, Houston, TX, 77030, USA
- Synthetic, Systems, and Physical Biology Program, Rice University, Houston, TX, 77005, USA
| | - Sangsin Lee
- Department of Bioengineering, Rice University, Houston, TX, 77030, USA
- Rice Neuroengineering Initiative, Rice University, Houston, TX, 77030, USA
| | - Vidal A Saenz
- Department of Bioengineering, Rice University, Houston, TX, 77030, USA
| | | | - Joycelyn Yiu
- Department of Bioengineering, Rice University, Houston, TX, 77030, USA
| | - Jerzy O Szablowski
- Department of Bioengineering, Rice University, Houston, TX, 77030, USA.
- Rice Neuroengineering Initiative, Rice University, Houston, TX, 77030, USA.
- Synthetic, Systems, and Physical Biology Program, Rice University, Houston, TX, 77005, USA.
- Applied Physics Program, Rice University, Houston, TX, 77005, USA.
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7
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Xu B, Zhang D, Yang B, Chen X, Jin Z, Qin X, Ma G, Sun K, Zhu L, Wei X, Yin H. Emerging trends in the blood spinal-cord barrier: A bibliometric analysis. Medicine (Baltimore) 2024; 103:e37125. [PMID: 38306548 PMCID: PMC10843562 DOI: 10.1097/md.0000000000037125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 01/10/2024] [Indexed: 02/04/2024] Open
Abstract
BACKGROUND The blood-spinal cord barrier (BSCB) is a unique protective barrier located between the circulatory system and the central nervous system. BSCB plays a vital role in various diseases. However, there is little systematic research and recording in this field by bibliometrics analysis. We aim to visualize this field through bibliometrics to analyze the hotspots and trends of BSCB and in order to facilitate an understanding of future developments in basic and clinical research. METHODS To conduct a bibliometric study of original publications and their references, the keywords Blood Spinal-Cord Barrier and BSCB are searched and filtered from the Web of Science database (2000-2022), focusing on citations, authors, journals, and countries/regions. Additionally, clustering of the references and co-citation analysis was completed, including a total of 1926 articles and comments. RESULTS From the results, 193 authors were identified, among which Sharma Hs played a key role. As far as the analysis result of the clustering of the references is concerned, the most common type in cluster analysis is spinal cord injury (SCI) which is a current and developing research field. The keywords are also the specific content under these clusters. The most influential organization is Univ Calif San Francisco, and "Proceedings of The National Academy of Sciences of The United States of America" magazine is the most cited magazine. CONCLUSION SUBSECTIONS The research on BSCB is booming focusing mainly on "BSCB in SCI" including "activation," "pathway," and "drug delivery" which is also the trend of future research.
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Affiliation(s)
- Bo Xu
- Wangjing Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Dian Zhang
- Wangjing Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- Graduate School, Beijing University of Chinese Medicine, Beijing, China
| | - Bowen Yang
- Wangjing Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Xin Chen
- Wangjing Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Zhefeng Jin
- Wangjing Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Xiaokuan Qin
- Wangjing Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Guoliang Ma
- Wangjing Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Kai Sun
- Wangjing Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Liguo Zhu
- Wangjing Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- Beijing Key Laboratory of Bone Setting Technology of Traditional Chinese Medicine, Beijing, China
| | - Xu Wei
- Wangjing Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - He Yin
- Wangjing Hospital, China Academy of Chinese Medical Sciences, Beijing, China
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8
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Frizado AP, O'Reilly MA. A numerical investigation of passive acoustic mapping for monitoring bubble-mediated focused ultrasound treatment of the spinal cord. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2023; 153:2271. [PMID: 37092915 DOI: 10.1121/10.0017836] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 03/28/2023] [Indexed: 05/03/2023]
Abstract
Focused ultrasound (FUS) combined with intravenous microbubbles (MBs) has been shown to increase drug delivery to the spinal cord in animal models. Eventual clinical translation of such a technique in the sensitive spinal cord requires robust treatment monitoring to ensure efficacy, localization, safety, and provide key intraprocedural feedback. Here, the use of passive acoustic mapping (PAM) of MB emissions with a spine-specific detector array in the context of transvertebral FUS sonications is investigated in silico. Using computed tomography-derived human vertebral geometry, transvertebral detection of MBs is evaluated over varying source locations with and without phase and amplitude corrections (PACs). The impact of prefocal cavitation is studied by simulating concurrent cavitation events in the canal and pre-laminar region. Spatially sensitive application of phase and amplitude is used to balance signal strengths emanating from different axial depths in combination with multiple dynamic ranges to elicit multisource viewing. Collectively, the results of this study encourage the use of PAM in transvertebral FUS applications with PACs to not only localize sources originating in the spinal canal but also multiple sources of innate amplitude mismatches when corrective methods are applied.
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Affiliation(s)
- Andrew Paul Frizado
- Department of Physical Sciences, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario, M4N 3M5, Canada
| | - Meaghan Anne O'Reilly
- Department of Physical Sciences, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario, M4N 3M5, Canada
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9
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Bhimreddy M, Routkevitch D, Hersh AM, Mohammadabadi A, Menta AK, Jiang K, Weber-Levine C, Davidar AD, Punnoose J, Kempski Leadingham KM, Doloff JC, Tyler B, Theodore N, Manbachi A. Disruption of the Blood-Spinal Cord Barrier using Low-Intensity Focused Ultrasound in a Rat Model. J Vis Exp 2023:10.3791/65113. [PMID: 36971451 PMCID: PMC10986840 DOI: 10.3791/65113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023] Open
Abstract
Low-intensity focused ultrasound (LIFU) uses ultrasonic pulsations at lower intensities than ultrasound and is being tested as a reversible and precise neuromodulatory technology. Although LIFU-mediated blood-brain barrier (BBB) opening has been explored in detail, no standardized technique for blood-spinal cord barrier (BSCB) opening has been established to date. Therefore, this protocol presents a method for successful BSCB disruption using LIFU sonication in a rat model, including descriptions of animal preparation, microbubble administration, target selection and localization, as well as BSCB disruption visualization and confirmation. The approach reported here is particularly useful for researchers who need a fast and cost-effective method to test and confirm target localization and precise BSCB disruption in a small animal model with a focused ultrasound transducer, evaluate the BSCB efficacy of sonication parameters, or explore applications for LIFU at the spinal cord, such as drug delivery, immunomodulation, and neuromodulation. Optimizing this protocol for individual use is recommended, especially for advancing future preclinical, clinical, and translational work.
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Affiliation(s)
- Meghana Bhimreddy
- Department of Neurosurgery, Johns Hopkins University School of Medicine
| | - Denis Routkevitch
- Department of Neurosurgery, Johns Hopkins University School of Medicine; Department of Biomedical Engineering, Johns Hopkins University; HEPIUS Innovation Laboratory, Johns Hopkins University School of Medicine
| | - Andrew M Hersh
- Department of Neurosurgery, Johns Hopkins University School of Medicine
| | - Ali Mohammadabadi
- Department of Neurosurgery, Johns Hopkins University School of Medicine; HEPIUS Innovation Laboratory, Johns Hopkins University School of Medicine
| | - Arjun K Menta
- Department of Neurosurgery, Johns Hopkins University School of Medicine
| | - Kelly Jiang
- Department of Neurosurgery, Johns Hopkins University School of Medicine
| | | | - A Daniel Davidar
- Department of Neurosurgery, Johns Hopkins University School of Medicine
| | - Joshua Punnoose
- Department of Neurosurgery, Johns Hopkins University School of Medicine; Department of Biomedical Engineering, Johns Hopkins University; HEPIUS Innovation Laboratory, Johns Hopkins University School of Medicine
| | - Kelley M Kempski Leadingham
- Department of Neurosurgery, Johns Hopkins University School of Medicine; HEPIUS Innovation Laboratory, Johns Hopkins University School of Medicine
| | - Joshua C Doloff
- Department of Biomedical Engineering, Johns Hopkins University
| | - Betty Tyler
- Department of Neurosurgery, Johns Hopkins University School of Medicine
| | - Nicholas Theodore
- Department of Neurosurgery, Johns Hopkins University School of Medicine; HEPIUS Innovation Laboratory, Johns Hopkins University School of Medicine
| | - Amir Manbachi
- Department of Neurosurgery, Johns Hopkins University School of Medicine; Department of Biomedical Engineering, Johns Hopkins University; HEPIUS Innovation Laboratory, Johns Hopkins University School of Medicine; Department of Electrical Engineering and Computer Science, Johns Hopkins University; Department of Mechanical Engineering, Johns Hopkins University; Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University;
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10
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Hersh AM, Jallo GI, Shimony N. Surgical approaches to intramedullary spinal cord astrocytomas in the age of genomics. Front Oncol 2022; 12:982089. [PMID: 36147920 PMCID: PMC9485889 DOI: 10.3389/fonc.2022.982089] [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: 06/30/2022] [Accepted: 08/11/2022] [Indexed: 11/25/2022] Open
Abstract
Intramedullary astrocytomas represent approximately 30%–40% of all intramedullary tumors and are the most common intramedullary tumor in children. Surgical resection is considered the mainstay of treatment in symptomatic patients with neurological deficits. Gross total resection (GTR) can be difficult to achieve as astrocytomas frequently present as diffuse lesions that infiltrate the cord. Therefore, GTR carries a substantial risk of new post-operative deficits. Consequently, subtotal resection and biopsy are often the only surgical options attempted. A midline or paramedian sulcal myelotomy is frequently used for surgical resection, although a dorsal root entry zone myelotomy can be used for lateral tumors. Intra-operative neuromonitoring using D-wave integrity, somatosensory, and motor evoked potentials is critical to facilitating a safe resection. Adjuvant radiation and chemotherapy, such as temozolomide, are often administered for high-grade recurrent or progressive lesions; however, consensus is lacking on their efficacy. Biopsied tumors can be analyzed for molecular markers that inform clinicians about the tumor’s prognosis and response to conventional as well as targeted therapeutic treatments. Stratification of intramedullary tumors is increasingly based on molecular features and mutational status. The landscape of genetic and epigenetic mutations in intramedullary astrocytomas is not equivalent to their intracranial counterparts, with important difference in frequency and type of mutations. Therefore, dedicated attention is needed to cohorts of patients with intramedullary tumors. Targeted therapeutic agents can be designed and administered to patients based on their mutational status, which may be used in coordination with traditional surgical resection to improve overall survival and functional status.
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Affiliation(s)
- Andrew M. Hersh
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - George I. Jallo
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Department of Neurosurgery, Johns Hopkins Medicine, Institute for Brain Protection Sciences, Johns Hopkins All Children’s Hospital, St. Petersburg, FL, United States
- *Correspondence: George I. Jallo,
| | - Nir Shimony
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Department of Surgery, St. Jude Children’s Research Hospital, Memphis, TN, United States
- Le Bonheur Neuroscience Institute, Le Bonheur Children’s Hospital, Memphis, TN, United States
- Department of Neurosurgery, University of Tennessee Health Science Center, Memphis, TN, United States
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11
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Athanassiadis AG, Ma Z, Moreno-Gomez N, Melde K, Choi E, Goyal R, Fischer P. Ultrasound-Responsive Systems as Components for Smart Materials. Chem Rev 2022; 122:5165-5208. [PMID: 34767350 PMCID: PMC8915171 DOI: 10.1021/acs.chemrev.1c00622] [Citation(s) in RCA: 75] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Indexed: 02/06/2023]
Abstract
Smart materials can respond to stimuli and adapt their responses based on external cues from their environments. Such behavior requires a way to transport energy efficiently and then convert it for use in applications such as actuation, sensing, or signaling. Ultrasound can carry energy safely and with low losses through complex and opaque media. It can be localized to small regions of space and couple to systems over a wide range of time scales. However, the same characteristics that allow ultrasound to propagate efficiently through materials make it difficult to convert acoustic energy into other useful forms. Recent work across diverse fields has begun to address this challenge, demonstrating ultrasonic effects that provide control over physical and chemical systems with surprisingly high specificity. Here, we review recent progress in ultrasound-matter interactions, focusing on effects that can be incorporated as components in smart materials. These techniques build on fundamental phenomena such as cavitation, microstreaming, scattering, and acoustic radiation forces to enable capabilities such as actuation, sensing, payload delivery, and the initiation of chemical or biological processes. The diversity of emerging techniques holds great promise for a wide range of smart capabilities supported by ultrasound and poses interesting questions for further investigations.
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Affiliation(s)
- Athanasios G. Athanassiadis
- Micro,
Nano, and Molecular Systems Group, Max Planck
Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Zhichao Ma
- Micro,
Nano, and Molecular Systems Group, Max Planck
Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Nicolas Moreno-Gomez
- Micro,
Nano, and Molecular Systems Group, Max Planck
Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany
- Institute
of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Kai Melde
- Micro,
Nano, and Molecular Systems Group, Max Planck
Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Eunjin Choi
- Micro,
Nano, and Molecular Systems Group, Max Planck
Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany
- Institute
of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Rahul Goyal
- Micro,
Nano, and Molecular Systems Group, Max Planck
Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Peer Fischer
- Micro,
Nano, and Molecular Systems Group, Max Planck
Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany
- Institute
of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
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12
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Xu R, O'Reilly MA. Establishing density-dependent longitudinal sound speed in the vertebral lamina. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2022; 151:1516. [PMID: 35364923 DOI: 10.1121/10.0009316] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 12/26/2021] [Indexed: 06/14/2023]
Abstract
Focused ultrasound treatments of the spinal cord may be facilitated using a phased array transducer and beamforming to correct spine-induced focal aberrations. Simulations can non-invasively calculate aberration corrections using x-ray computed tomography (CT) data that are correlated to density (ρ) and longitudinal sound speed (cL). We aimed to optimize vertebral lamina-specific cL(ρ) functions at a physiological temperature (37 °C) to maximize time domain simulation accuracy. Odd-numbered ex vivo human thoracic vertebrae were imaged with a clinical CT-scanner (0.511 × 0.511 × 0.5 mm), then sonicated with a transducer (514 kHz) focused on the canal via the vertebral lamina. Vertebra-induced signal time shifts were extracted from pressure waveforms recorded within the canals. Measurements were repeated 5× per vertebra, with 2.5 mm vertical vertebra shifts between measurements. Linear functions relating cL with CT-derived density were optimized. The optimized function was cL(ρ)=0.35(ρ-ρw)+ cL,w m/s, where w denotes water, giving the tested laminae a mean bulk density of 1600 ± 30 kg/m3 and a mean bulk cL of 1670 ± 60 m/s. The optimized lamina cL(ρ) function was accurate to λ/16 when implemented in a multi-layered ray acoustics model. This modelling accuracy will improve trans-spine ultrasound beamforming.
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Affiliation(s)
- Rui Xu
- Department of Medical Biophysics, University of Toronto, 101 College Street, Suite 15-701, Toronto, Ontario, M5G 1L7, Canada
| | - Meaghan A O'Reilly
- Physical Sciences Platform, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario, M4N 3M5, Canada
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Kung Y, Chen KY, Liao WH, Hsu YH, Wu CH, Hsiao MY, Huang APH, Chen WS. Facilitating drug delivery in the central nervous system by opening the blood-cerebrospinal fluid barrier with a single low energy shockwave pulse. Fluids Barriers CNS 2022; 19:3. [PMID: 34991647 PMCID: PMC8740485 DOI: 10.1186/s12987-021-00303-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 12/27/2021] [Indexed: 12/19/2022] Open
Abstract
Background The blood-cerebrospinal fluid (CSF) barrier (BCSFB) is critically important to the pathophysiology of the central nervous system (CNS). However, this barrier prevents the safe transmission of beneficial drugs from the blood to the CSF and thus the spinal cord and brain, limiting their effectiveness in treating a variety of CNS diseases. Methods This study demonstrates a method on SD rats for reversible and site-specific opening of the BCSFB via a noninvasive, low-energy focused shockwave (FSW) pulse (energy flux density 0.03 mJ/mm2) with SonoVue microbubbles (2 × 106 MBs/kg), posing a low risk of injury. Results By opening the BCSFB, the concentrations of certain CNS-impermeable indicators (70 kDa Evans blue and 500 kDa FITC-dextran) and drugs (penicillin G, doxorubicin, and bevacizumab) could be significantly elevated in the CSF around both the brain and the spinal cord. Moreover, glioblastoma model rats treated by doxorubicin with this FSW-induced BCSFB (FSW-BCSFB) opening technique also survived significantly longer than untreated controls. Conclusion This is the first study to demonstrate and validate a method for noninvasively and selectively opening the BCSFB to enhance drug delivery into CSF circulation. Potential applications may include treatments for neurodegenerative diseases, CNS infections, brain tumors, and leptomeningeal carcinomatosis. Supplementary Information The online version contains supplementary material available at 10.1186/s12987-021-00303-x.
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Affiliation(s)
- Yi Kung
- Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital & National Taiwan University College of Medicine, Taipei City, Taiwan
| | - Kuan-Yu Chen
- Division of Pulmonology, Department of Internal Medicine, National Taiwan University Hospital and College of Medicine, Taipei City, Taiwan
| | - Wei-Hao Liao
- Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital & National Taiwan University College of Medicine, Taipei City, Taiwan
| | - Yi-Hua Hsu
- Department of Surgery, National Taiwan University Hospital, Taipei City, Taiwan
| | - Chueh-Hung Wu
- Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital & National Taiwan University College of Medicine, Taipei City, Taiwan
| | - Ming-Yen Hsiao
- Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital & National Taiwan University College of Medicine, Taipei City, Taiwan
| | - Abel P-H Huang
- Department of Surgery, National Taiwan University Hospital, Taipei City, Taiwan.
| | - Wen-Shiang Chen
- Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital & National Taiwan University College of Medicine, Taipei City, Taiwan. .,Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Miaoli, Taiwan.
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Fletcher SMP, Choi M, Ramesh R, O'Reilly MA. Focused Ultrasound-Induced Blood-Spinal Cord Barrier Opening Using Short-Burst Phase-Keying Exposures in Rats: A Parameter Study. ULTRASOUND IN MEDICINE & BIOLOGY 2021; 47:1747-1760. [PMID: 33879388 DOI: 10.1016/j.ultrasmedbio.2021.03.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 03/05/2021] [Accepted: 03/12/2021] [Indexed: 06/12/2023]
Abstract
Transient opening of the blood-spinal cord barrier has the potential to improve drug delivery options to the spinal cord. We previously developed short-burst phase-keying exposures to reduce focal depth of field and mitigate standing waves in the spinal canal. However, optimal short-burst phase-keying parameters for drug delivery have not been identified. Here, the effects of pressure, treatment duration, pulse length, burst repetition frequency and burst length on resulting tissue effects were investigated. Increased in situ pressures (0.23-0.33 MPa) led to increased post-treatment T1-weighted contrast enhancement in magnetic resonance imaging (p = 0.015). Increased treatment duration (120 vs. 300 s) led to increased enhancement, but without statistical significance (p = 0.056). Increased burst repetition frequency (20 vs. 40 kHz) yielded a non-significant increase in enhancement (p = 0.064) but corresponded with increased damage observed on histology. No difference was observed in enhancement between pulse lengths of 2 and 10 ms (p = 0.912), corresponding with a sharp drop in the recorded second harmonic signal during the first 2 ms of the pulse. Increasing the burst length from two to five cycles (514 kHz) led to increased enhancement (p = 0.014). Results indicate that increasing the burst length may be the most effective method to enhance drug delivery. Additionally, shorter pulse lengths may allow more interleaved targets, and therefore a larger treatment volume, within one sonication.
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Affiliation(s)
- Stecia-Marie P Fletcher
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
| | - Min Choi
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Ranjith Ramesh
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Meaghan A O'Reilly
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
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Characterization of ultrasound-mediated delivery of trastuzumab to normal and pathologic spinal cord tissue. Sci Rep 2021; 11:4412. [PMID: 33627726 PMCID: PMC7904756 DOI: 10.1038/s41598-021-83874-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 02/08/2021] [Indexed: 01/31/2023] Open
Abstract
Extensive studies on focused ultrasound (FUS)-mediated drug delivery through the blood-brain barrier have been published, yet little work has been published on FUS-mediated drug delivery through the blood-spinal cord barrier (BSCB). This work aims to quantify the delivery of the monoclonal antibody trastuzumab to rat spinal cord tissue and characterize its distribution within a model of leptomeningeal metastases. 10 healthy Sprague-Dawley rats were treated with FUS + trastuzumab and sacrificed at 2-h or 24-h post-FUS. A human IgG ELISA (Abcam) was used to measure trastuzumab concentration and a 12 ± fivefold increase was seen in treated tissue over control tissue at 2 h versus no increase at 24 h. Three athymic nude rats were inoculated with MDA-MB-231-H2N HER2 + breast cancer cells between the meninges in the thoracic region of the spinal cord and treated with FUS + trastuzumab. Immunohistochemistry was performed to visualize trastuzumab delivery, and semi-quantitative analysis revealed similar or more intense staining in tumor tissue compared to healthy tissue suggesting a comparable or greater concentration of trastuzumab was achieved. FUS can increase the permeability of the BSCB, improving drug delivery to specifically targeted regions of healthy and pathologic tissue in the spinal cord. The achieved concentrations within the healthy tissue are comparable to those reported in the brain.
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