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Kalyani P, Lippa SM, Werner JK, Amyot F, Moore CB, Kenney K, Diaz-Arrastia R. Phosphodiesterase-5 (PDE-5) Inhibitors as Therapy for Cerebrovascular Dysfunction in Chronic Traumatic Brain Injury. Neurotherapeutics 2023; 20:1629-1640. [PMID: 37697134 PMCID: PMC10684467 DOI: 10.1007/s13311-023-01430-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/22/2023] [Indexed: 09/13/2023] Open
Abstract
Multiple phase III randomized controlled trials (RCTs) for pharmacologic interventions in traumatic brain injury (TBI) have failed despite promising results in experimental models. The heterogeneity of TBI, in terms of pathomechanisms and impacted brain structures, likely contributes to these failures. Biomarkers have been recommended to identify patients with relevant pathology (predictive biomarkers) and confirm target engagement and monitor therapy response (pharmacodynamic biomarkers). Our group focuses on traumatic cerebrovascular injury as an understudied endophenotype of TBI and is validating a predictive and pharmacodynamic imaging biomarker (cerebrovascular reactivity; CVR) in moderate-severe TBI. We aim to extend these studies to milder forms of TBI to determine the optimal dose of sildenafil for maximal improvement in CVR. We will conduct a phase II dose-finding study involving 160 chronic TBI patients (mostly mild) using three doses of sildenafil, a phosphodiesterase-5 (PDE-5) inhibitor. The study measures baseline CVR and evaluates the effect of escalating sildenafil doses on CVR improvement. A 4-week trial of thrice daily sildenafil will assess safety, tolerability, and clinical efficacy. This dual-site 4-year study, funded by the Department of Defense and registered in ClinicalTrials.gov (NCT05782244), plans to launch in June 2023. Biomarker-informed RCTs are essential for developing effective TBI interventions, relying on an understanding of underlying pathomechanisms. Traumatic microvascular injury (TMVI) is an attractive mechanism which can be targeted by vaso-active drugs such as PDE-5 inhibitors. CVR is a potential predictive and pharmacodynamic biomarker for targeted interventions aimed at TMVI. (Trial registration: NCT05782244, ClinicalTrials.gov ).
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Affiliation(s)
- Priyanka Kalyani
- Department of Neurology, University of Pennsylvania, 3400 Spruce St, Philadelphia, PA, 19104, USA.
| | - Sara M Lippa
- Walter Reed National Military Medical Center, The National Intrepid Center of Excellence, Palmer Rd S, Bethesda, MD, 20814, USA
- Department of Neuroscience, Uniformed Services University Health Sciences, 4301, Jones Bridge Rd, Bethesda, MD, 20814, USA
| | - J Kent Werner
- Walter Reed National Military Medical Center, The National Intrepid Center of Excellence, Palmer Rd S, Bethesda, MD, 20814, USA
- Department of Neuroscience, Uniformed Services University Health Sciences, 4301, Jones Bridge Rd, Bethesda, MD, 20814, USA
| | - Franck Amyot
- Walter Reed National Military Medical Center, The National Intrepid Center of Excellence, Palmer Rd S, Bethesda, MD, 20814, USA
| | - Carol B Moore
- Department of Neuroscience, Uniformed Services University Health Sciences, 4301, Jones Bridge Rd, Bethesda, MD, 20814, USA
| | - Kimbra Kenney
- Department of Neuroscience, Uniformed Services University Health Sciences, 4301, Jones Bridge Rd, Bethesda, MD, 20814, USA
| | - Ramon Diaz-Arrastia
- Department of Neurology, University of Pennsylvania, 3400 Spruce St, Philadelphia, PA, 19104, USA
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ElHady AK, El-Gamil DS, Abdel-Halim M, Abadi AH. Advancements in Phosphodiesterase 5 Inhibitors: Unveiling Present and Future Perspectives. Pharmaceuticals (Basel) 2023; 16:1266. [PMID: 37765073 PMCID: PMC10536424 DOI: 10.3390/ph16091266] [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: 07/12/2023] [Revised: 08/25/2023] [Accepted: 09/05/2023] [Indexed: 09/29/2023] Open
Abstract
Phosphodiesterase 5 (PDE5) inhibitors presented themselves as important players in the nitric oxide/cGMP pathway, thus exerting a profound impact on various physiological and pathological processes. Beyond their well-known efficacy in treating male erectile dysfunction (ED) and pulmonary arterial hypertension (PAH), a plethora of studies have unveiled their significance in the treatment of a myriad of other diseases, including cognitive functions, heart failure, multiple drug resistance in cancer therapy, immune diseases, systemic sclerosis and others. This comprehensive review aims to provide an updated assessment of the crucial role played by PDE5 inhibitors (PDE5-Is) as disease-modifying agents taking their limiting side effects into consideration. From a medicinal chemistry and drug discovery perspective, the published PDE5-Is over the last 10 years and their binding characteristics are systemically discussed, and advancement in properties is exposed. A persistent challenge encountered with these agents lies in their limited isozyme selectivity; considering this obstacle, this review also highlights the breakthrough development of the recently reported PDE5 allosteric inhibitors, which exhibit an unparalleled level of selectivity that was rarely achievable by competitive inhibitors. The implications and potential impact of these novel allosteric inhibitors are meticulously explored. Additionally, the concept of multi-targeted ligands is critically evaluated in relation to PDE5-Is by inspecting the broader spectrum of their molecular interactions and effects. The objective of this review is to provide insight into the design of potent, selective PDE5-Is and an overview of their biological function, limitations, challenges, therapeutic potentials, undergoing clinical trials, future prospects and emerging uses, thus guiding upcoming endeavors in both academia and industry within this domain.
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Affiliation(s)
- Ahmed K. ElHady
- School of Life and Medical Sciences, University of Hertfordshire Hosted by Global Academic Foundation, New Administrative Capital, Cairo 11865, Egypt;
| | - Dalia S. El-Gamil
- Department of Chemistry, Faculty of Pharmacy, Ahram Canadian University, Cairo 12451, Egypt;
| | - Mohammad Abdel-Halim
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy and Biotechnology, German University in Cairo, Cairo 11835, Egypt;
| | - Ashraf H. Abadi
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy and Biotechnology, German University in Cairo, Cairo 11835, Egypt;
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3
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Wang Q, Shin B, Oh S, Shin YS, Na DL, Kim KW. A pilot study to explore the effect of udenafil on cerebral hemodynamics in older adults. Ann Clin Transl Neurol 2023; 10:933-943. [PMID: 37013976 PMCID: PMC10270257 DOI: 10.1002/acn3.51774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 03/17/2023] [Accepted: 03/18/2023] [Indexed: 04/05/2023] Open
Abstract
OBJECTIVE Phosphodiesterase-5 inhibitors (PDE5Is) enhance vasodilation. We investigated the effects of PDE5I on cerebral hemodynamics during cognitive tasks using functional near-infrared spectroscopy (fNIRS). METHODS This study used a crossover design. Twelve cognitively healthy men participants (mean age, 59 ± 3 years; range, 55-65 years) were recruited and randomly assigned to the experimental or control arm, then the experimental and control arm were exchanged after 1 week. Udenafil 100 mg was administered to participants in the experimental arm once daily for 3 days. We measured the fNIRS signal during the resting state and four cognitive tasks three times for each participant: at baseline, in the experimental arm, and in the control arm. RESULTS Behavioral data did not show a significant difference between the experimental and control arms. The fNIRS signal showed significant decreases in the experimental arm compared to the control arm during several cognitive tests: verbal fluency test (left dorsolateral prefrontal cortex, T = -3.02, p = 0.014; left frontopolar cortex, T = -4.37, p = 0.002; right dorsolateral prefrontal cortex, T = -2.59, p = 0.027), Korean-color word Stroop test (left orbitofrontal cortex, T = -3.61, p = 0.009), and social event memory test (left dorsolateral prefrontal cortex, T = -2.35, p = 0.043; left frontopolar cortex, T = -3.35, p = 0.01). INTERPRETATION Our results showed a paradoxical effect of udenafil on cerebral hemodynamics in older adults. This contradicts our hypothesis, but it suggests that fNIRS is sensitive to changes in cerebral hemodynamics in response to PDE5Is.
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Affiliation(s)
- Qi Wang
- Medical SchoolJeonbuk National UniversityJeonjuSouth Korea
| | - Byoung‐Soo Shin
- Department of NeurologyJeonbuk National University Medical School and HospitalJeonjuSouth Korea
- Research Institute of Clinical Medicine of Jeonbuk National University‐Biomedical Research Institute of Jeonbuk National University HospitalJeonjuSouth Korea
| | - Sun‐Young Oh
- Department of NeurologyJeonbuk National University Medical School and HospitalJeonjuSouth Korea
- Research Institute of Clinical Medicine of Jeonbuk National University‐Biomedical Research Institute of Jeonbuk National University HospitalJeonjuSouth Korea
| | - Yu Seob Shin
- Research Institute of Clinical Medicine of Jeonbuk National University‐Biomedical Research Institute of Jeonbuk National University HospitalJeonjuSouth Korea
- Department of UrologyJeonbuk National University Medical School and HospitalJeonjuSouth Korea
| | - Duk L. Na
- Department of NeurologySungkyunkwan University School of Medicine, Samsung Medical CenterSeoulSouth Korea
| | - Ko Woon Kim
- Department of NeurologyJeonbuk National University Medical School and HospitalJeonjuSouth Korea
- Research Institute of Clinical Medicine of Jeonbuk National University‐Biomedical Research Institute of Jeonbuk National University HospitalJeonjuSouth Korea
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4
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Gaggi NL, Ware JB, Dolui S, Brennan D, Torrellas J, Wang Z, Whyte J, Diaz-Arrastia R, Kim JJ. Temporal dynamics of cerebral blood flow during the first year after moderate-severe traumatic brain injury: A longitudinal perfusion MRI study. Neuroimage Clin 2023; 37:103344. [PMID: 36804686 PMCID: PMC9969322 DOI: 10.1016/j.nicl.2023.103344] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 02/01/2023] [Accepted: 02/04/2023] [Indexed: 02/13/2023]
Abstract
Traumatic brain injury (TBI) is associated with alterations in cerebral blood flow (CBF), which may underlie functional disability and precipitate TBI-induced neurodegeneration. Although it is known that chronic moderate-severe TBI (msTBI) causes decreases in CBF, the temporal dynamics during the early chronic phase of TBI remain unknown. Using arterial spin labeled (ASL) perfusion magnetic resonance imaging (MRI), we examined longitudinal CBF changes in 29 patients with msTBI at 3, 6, and 12 months post-injury in comparison to 35 demographically-matched healthy controls (HC). We investigated the difference between the two groups and the within-subject time effect in the TBI patients using whole-brain voxel-wise analysis. Mean CBF in gray matter (GM) was lower in the TBI group compared to HC at 6 and 12 months post-injury. Within the TBI group, we identified widespread regional decreases in CBF from 3 to 6 months post-injury. In contrast, there were no regions with decreasing CBF from 6 to 12 months post-injury, indicating stabilization of hypoperfusion. There was instead a small area of increase in CBF observed in the right precuneus. These CBF changes were not accompanied by cortical atrophy. The change in CBF was correlated with change in executive function from 3 to 6 months post-injury in TBI patients, suggesting functional relevance of CBF measures. Understanding the time course of TBI-induced hypoperfusion and its relationship with cognitive improvement could provide an optimal treatment window to benefit long-term outcome.
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Affiliation(s)
- Naomi L Gaggi
- City University of New York (CUNY) School of Medicine, Townsend Harris Hall, 160 Convent Avenue, Convent Avenue, New York, NY 10031, United States; City University of New York (CUNY) Graduate Center, 365 5(th) Avenue, New York, NY 10016, United States.
| | - Jeffrey B Ware
- University of Pennsylvania, Perelman School of Medicine, 3400 Civic Center Boulevard, Philadelphia, PA 19104, United States.
| | - Sudipto Dolui
- University of Pennsylvania, Perelman School of Medicine, 3400 Civic Center Boulevard, Philadelphia, PA 19104, United States.
| | - Daniel Brennan
- City University of New York (CUNY) School of Medicine, Townsend Harris Hall, 160 Convent Avenue, Convent Avenue, New York, NY 10031, United States; City University of New York (CUNY) Graduate Center, 365 5(th) Avenue, New York, NY 10016, United States.
| | - Julia Torrellas
- City University of New York (CUNY) School of Medicine, Townsend Harris Hall, 160 Convent Avenue, Convent Avenue, New York, NY 10031, United States.
| | - Ze Wang
- University of Maryland School of Medicine, 655 W Baltimore St. S, Baltimore, MD 21201, United States.
| | - John Whyte
- Moss Rehabilitation Research Institute, 50 Township Line Road, Elkins Park, PA 19027, United States.
| | - Ramon Diaz-Arrastia
- University of Pennsylvania, Perelman School of Medicine, 3400 Civic Center Boulevard, Philadelphia, PA 19104, United States.
| | - Junghoon J Kim
- City University of New York (CUNY) School of Medicine, Townsend Harris Hall, 160 Convent Avenue, Convent Avenue, New York, NY 10031, United States; City University of New York (CUNY) Graduate Center, 365 5(th) Avenue, New York, NY 10016, United States.
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5
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Amyot F, Davis C, Sangobowale M, Moore C, Silverman E, Gandjbakhche A, Diaz-Arrastia R, Kenney K. Cerebrovascular Reactivity Measurement with Functional Near Infrared Spectroscopy. J Vis Exp 2022:10.3791/61284. [PMID: 35723463 PMCID: PMC11189107 DOI: 10.3791/61284] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/22/2024] Open
Abstract
Cerebrovascular reactivity (CVR) is the capacity of blood vessels in the brain to alter cerebral blood flow (either with dilation or constriction) in response to chemical or physical stimuli. The amount of reactivity in the cerebral microvasculature depends on the integrity of the capacitance vasculature and is the primary function of endothelial cells. CVR is, therefore, an indicator of the microvasculature's physiology and overall health. Imaging methods that can measure CVR are available but can be costly, and require magnetic resonance imaging centers and technical expertise. In this study, we used fNIRS technology to monitor changes of oxyhemoglobin (HbO) and deoxyhemoglobin (HbR) in the cerebral microvasculature to assess the CVR of 15 healthy controls (HC) in response to a vasoactive stimulus (inhaled 5% carbon dioxide or CO2). Our results suggest that this is a promising imaging technology that offers a non-invasive, accurate, portable, and cost-effective method of mapping cortical CVR and associated microvasculature function, resulting from a traumatic brain injury or other conditions associated with cerebral microvasculopathy.
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Affiliation(s)
- Franck Amyot
- National Intrepid Center of Excellence, Walter Reed National Military Medical Center;
| | - Cora Davis
- National Intrepid Center of Excellence, Walter Reed National Military Medical Center
| | | | - Carol Moore
- Uniformed Services University of the Health Sciences
| | | | - Amir Gandjbakhche
- The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health
| | | | - Kimbra Kenney
- National Intrepid Center of Excellence, Walter Reed National Military Medical Center; Uniformed Services University of the Health Sciences
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Zinni M, Pansiot J, Léger PL, El Kamouh M, Baud O. Sildenafil-Mediated Neuroprotection from Adult to Neonatal Brain Injury: Evidence, Mechanisms, and Future Translation. Cells 2021; 10:cells10102766. [PMID: 34685745 PMCID: PMC8534574 DOI: 10.3390/cells10102766] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 09/28/2021] [Accepted: 10/07/2021] [Indexed: 12/12/2022] Open
Abstract
Cerebral stroke, traumatic brain injury, and hypoxic ischemic encephalopathy are among the most frequently occurring brain injuries. A complex pathogenesis, characterized by a synergistic interaction between alterations of the cerebrovascular system, cell death, and inflammation, is at the basis of the brain damage that leads to behavioral and neurodevelopmental disabilities in affected subjects. Sildenafil is a selective inhibitor of the enzyme phosphodiesterase 5 (PDE5) that is able to cross the blood-brain barrier. Preclinical data suggest that sildenafil may be a good candidate for the prevention or repair of brain injury in both adults and neonates. The aim of this review is to summarize the evidence supporting the neuroprotective action of sildenafil and discuss the possible benefits of the association of sildenafil with current therapeutic strategies.
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Affiliation(s)
- Manuela Zinni
- Inserm UMR1141 NeuroDiderot, Université de Paris, 75019 Paris, France; (M.Z.); (J.P.); (M.E.K.)
| | - Julien Pansiot
- Inserm UMR1141 NeuroDiderot, Université de Paris, 75019 Paris, France; (M.Z.); (J.P.); (M.E.K.)
| | - Pierre-Louis Léger
- Pediatric and Neonatal Intensive Care Unit, Armand-Trousseau University Hospital, Assistance Publique-Hôpitaux de Paris, Sorbonne University, 75019 Paris, France;
| | - Marina El Kamouh
- Inserm UMR1141 NeuroDiderot, Université de Paris, 75019 Paris, France; (M.Z.); (J.P.); (M.E.K.)
- Laboratoire de Physiologie et Génomique des Poissons-INRAE, 35700 Rennes, France
| | - Olivier Baud
- Laboratory of Child Growth and Development, University of Geneva, 1211 Geneva, Switzerland
- Division of Neonatology and Pediatric Intensive Care, Children’s University Hospital of Geneva, 1211 Geneva, Switzerland
- Correspondence: ; Tel.: +41-795-534-204
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7
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Xu L, Ware JB, Kim JJ, Shahim P, Silverman E, Magdamo B, Dabrowski C, Wesley L, Le MD, Morrison J, Zamore H, Lynch CE, Petrov D, Chen HI, Schuster J, Diaz-Arrastia R, Sandsmark DK. Arterial Spin Labeling Reveals Elevated Cerebral Blood Flow with Distinct Clusters of Hypo- and Hyperperfusion after Traumatic Brain Injury. J Neurotrauma 2021; 38:2538-2548. [PMID: 34115539 PMCID: PMC8403182 DOI: 10.1089/neu.2020.7553] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Imaging detection of brain perfusion alterations after traumatic brain injury (TBI) may provide prognostic insights. In this study, we used arterial spin labeling (ASL) to quantify cross-sectional and longitudinal changes in cerebral blood flow (CBF) after TBI and correlated changes with clinical outcome. We analyzed magnetic resonance imaging scans from adult participants with TBI requiring hospitalization in the acute (2 weeks post-injury, n = 33) and chronic (6 months post-injury, n = 16) phases, with 13 participants scanned longitudinally at both time points. We also analyzed 18 age- and sex-matched healthy controls. Whole-brain CBF maps were derived using a three-dimensional pseudo-continuous arterial spin label technique. Mean CBF across tissue-based regions (whole brain, gray matter, and white matter) was compared cross-sectionally and longitudinally. In addition, individual-level clusters of abnormal perfusion were identified using voxel-based z-score analysis of relative CBF maps, and number and volume of abnormally hypo- and hyperperfused clusters were assessed cross-sectionally and longitudinally. Finally, all CBF measures were correlated with clinical outcome measures. Mean global and gray matter CBF were significantly elevated in acute and chronic TBI participants compared to controls. Participants with better outcome at 6 months post-injury tended to have higher CBF in the acute phase compared to those with poorer outcome. Acute TBI participants had a significantly greater volume of hypo- and hyperperfused brain tissue compared to controls, with these regions partially normalizing by the chronic phase. Our findings demonstrate global elevation of CBF with focal hypo- and hyperperfusion in the early post-injury period and suggest a reparative role for acute elevation in CBF post-TBI.
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Affiliation(s)
- Linda Xu
- The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Jeffrey B. Ware
- The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Junghoon J. Kim
- CUNY School of Medicine, The City College of New York, New York, New York, USA
| | | | - Erika Silverman
- The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Brigid Magdamo
- The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Cian Dabrowski
- The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Leroy Wesley
- The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - My Duyen Le
- The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Justin Morrison
- The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Hannah Zamore
- The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Cillian E. Lynch
- The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Dmitriy Petrov
- The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - H. Isaac Chen
- The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - James Schuster
- The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Ramon Diaz-Arrastia
- The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Danielle K. Sandsmark
- The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
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8
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Barlow KM, Iyer K, Yan T, Scurfield A, Carlson H, Wang Y. Cerebral Blood Flow Predicts Recovery in Children with Persistent Post-Concussion Symptoms after Mild Traumatic Brain Injury. J Neurotrauma 2021; 38:2275-2283. [PMID: 33430707 PMCID: PMC9009764 DOI: 10.1089/neu.2020.7566] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Persistent post-concussion symptoms (PPCS) following pediatric mild traumatic brain injury (mTBI) are associated with differential changes in cerebral blood flow (CBF). Given its potential as a therapeutic target, we examined CBF changes during recovery in children with PPCS. We hypothesized that CBF would decrease and that such decreases would mirror clinical recovery. In a prospective cohort study, 61 children and adolescents (mean age 14 [standard deviation = 2.6] years; 41% male) with PPCS were imaged with three-dimensional (3D) pseudo-continuous arterial spin-labelled (pCASL) magnetic resonance imaging (MRI) at 4-6 and 8-10 weeks post-injury. Exclusion criteria included any significant past medical history and/or previous concussion within the past 3 months. Twenty-three participants had clinically recovered at the time of the second scan. We found that relative and mean absolute CBF were higher in participants with poor recovery, 44.0 (95% confidence interval [CI]: 43.32, 44.67) than in those with good recovery, 42.19 (95% CI: 41.77, 42.60) mL/min/100 g gray tissue and decreased over time (β = -1.75; p < 0.001). The decrease was greater in those with good recovery (β = 2.29; p < 0.001) and predicted outcome in 77% of children with PPCS (odds ratio [OR] 0.54, 95% CI: 0.36, 0.80; p = 0.002). Future studies are warranted to validate the utility of CBF as a useful predictive biomarker of outcome in PPCS.
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Affiliation(s)
- Karen M. Barlow
- Children's Health Research Centre, University of Queensland, Brisbane, Queensland, Australia
- Queensland Children's Hospital, Children's Health Queensland, Brisbane, Queensland, Australia
- Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Kartik Iyer
- Children's Health Research Centre, University of Queensland, Brisbane, Queensland, Australia
| | - Tingting Yan
- Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Alex Scurfield
- Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Helen Carlson
- Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Yang Wang
- Department of Radiology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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9
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Haber M, Amyot F, Lynch CE, Sandsmark DK, Kenney K, Werner JK, Moore C, Flesher K, Woodson S, Silverman E, Chou Y, Pham D, Diaz-Arrastia R. Imaging biomarkers of vascular and axonal injury are spatially distinct in chronic traumatic brain injury. J Cereb Blood Flow Metab 2021; 41:1924-1938. [PMID: 33444092 PMCID: PMC8327117 DOI: 10.1177/0271678x20985156] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 10/07/2020] [Accepted: 12/06/2020] [Indexed: 11/17/2022]
Abstract
Traumatic Brain Injury (TBI) is associated with both diffuse axonal injury (DAI) and diffuse vascular injury (DVI), which result from inertial shearing forces. These terms are often used interchangeably, but the spatial relationships between DAI and DVI have not been carefully studied. Multimodal magnetic resonance imaging (MRI) can help distinguish these injury mechanisms: diffusion tensor imaging (DTI) provides information about axonal integrity, while arterial spin labeling (ASL) can be used to measure cerebral blood flow (CBF), and the reactivity of the Blood Oxygen Level Dependent (BOLD) signal to a hypercapnia challenge reflects cerebrovascular reactivity (CVR). Subjects with chronic TBI (n = 27) and healthy controls (n = 14) were studied with multimodal MRI. Mean values of mean diffusivity (MD), fractional anisotropy (FA), CBF, and CVR were extracted for pre-determined regions of interest (ROIs). Normalized z-score maps were generated from the pool of healthy controls. Abnormal ROIs in one modality were not predictive of abnormalities in another. Approximately 9-10% of abnormal voxels for CVR and CBF also showed an abnormal voxel value for MD, while only 1% of abnormal CVR and CBF voxels show a concomitant abnormal FA value. These data indicate that DAI and DVI represent two distinct TBI endophenotypes that are spatially independent.
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Affiliation(s)
- Margalit Haber
- Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - Franck Amyot
- National Intrepid Center of Excellence, Walter Reed National Military Medical Center, Bethesda, MD, USA
| | - Cillian E Lynch
- Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - Danielle K Sandsmark
- Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - Kimbra Kenney
- National Intrepid Center of Excellence, Walter Reed National Military Medical Center, Bethesda, MD, USA
- Department of Neurology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - John K Werner
- Department of Neurology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Carol Moore
- Department of Neurology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Kelley Flesher
- Department of Neurology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Sarah Woodson
- Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - Erika Silverman
- Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - Yiyu Chou
- Center for Neuroscience and Regenerative Medicine, Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, USA
| | - Dzung Pham
- Center for Neuroscience and Regenerative Medicine, Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, USA
| | - Ramon Diaz-Arrastia
- Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
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10
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Lynch CE, Eisenbaum M, Algamal M, Balbi M, Ferguson S, Mouzon B, Saltiel N, Ojo J, Diaz-Arrastia R, Mullan M, Crawford F, Bachmeier C. Impairment of cerebrovascular reactivity in response to hypercapnic challenge in a mouse model of repetitive mild traumatic brain injury. J Cereb Blood Flow Metab 2021; 41:1362-1378. [PMID: 33050825 PMCID: PMC8142124 DOI: 10.1177/0271678x20954015] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Incidences of repetitive mild TBI (r-mTBI), like those sustained by contact sports athletes and military personnel, are thought to be a risk factor for development of neurodegenerative disorders. Those suffering from chronic TBI-related illness demonstrate deficits in cerebrovascular reactivity (CVR), the ability of the cerebral vasculature to respond to a vasoactive stimulus. CVR is thus an important measure of traumatic cerebral vascular injury (TCVI), and a possible in vivo endophenotype of TBI-related neuropathogenesis. We combined laser speckle imaging of CVR in response to hypercapnic challenge with neurobehavioral assessment of learning and memory, to investigate if decreased cerebrovascular responsiveness underlies impaired cognitive function in our mouse model of chronic r-mTBI. We demonstrate a profile of blunted hypercapnia-evoked CVR in the cortices of r-mTBI mice like that of human TBI, alongside sustained memory and learning impairment, without biochemical or immunohistopathological signs of cerebral vessel laminar or endothelium constituent loss. Transient decreased expression of alpha smooth muscle actin and platelet-derived growth factor receptor β, indicative of TCVI, is obvious only at the time of the most pronounced CVR deficit. These findings implicate CVR as a valid preclinical measure of TCVI, perhaps useful for developing therapies targeting TCVI after recurrent mild head trauma.
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Affiliation(s)
- Cillian E Lynch
- The Roskamp Institute, Sarasota, FL, USA.,Department of Life Sciences, The Open University, Milton Keynes, UK.,James A. Haley Veteran's Administration, Tampa, FL, USA.,Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Maxwell Eisenbaum
- The Roskamp Institute, Sarasota, FL, USA.,Department of Life Sciences, The Open University, Milton Keynes, UK
| | - Moustafa Algamal
- The Roskamp Institute, Sarasota, FL, USA.,Department of Life Sciences, The Open University, Milton Keynes, UK
| | - Matilde Balbi
- Department of Psychiatry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Scott Ferguson
- The Roskamp Institute, Sarasota, FL, USA.,Department of Life Sciences, The Open University, Milton Keynes, UK
| | - Benoit Mouzon
- The Roskamp Institute, Sarasota, FL, USA.,Department of Life Sciences, The Open University, Milton Keynes, UK.,James A. Haley Veteran's Administration, Tampa, FL, USA
| | | | - Joseph Ojo
- The Roskamp Institute, Sarasota, FL, USA.,Department of Life Sciences, The Open University, Milton Keynes, UK.,James A. Haley Veteran's Administration, Tampa, FL, USA
| | - Ramon Diaz-Arrastia
- Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Mike Mullan
- The Roskamp Institute, Sarasota, FL, USA.,Department of Life Sciences, The Open University, Milton Keynes, UK
| | - Fiona Crawford
- The Roskamp Institute, Sarasota, FL, USA.,Department of Life Sciences, The Open University, Milton Keynes, UK.,James A. Haley Veteran's Administration, Tampa, FL, USA
| | - Corbin Bachmeier
- The Roskamp Institute, Sarasota, FL, USA.,Department of Life Sciences, The Open University, Milton Keynes, UK.,Bay Pines VA Healthcare System, Bay Pines, FL, USA
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11
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Amyot F, Lynch CE, Ollinger J, Werner JK, Silverman E, Moore C, Davis C, Turtzo LC, Diaz-Arrastia R, Kenney K. Cerebrovascular Reactivity Measures Are Associated With Post-traumatic Headache Severity in Chronic TBI; A Retrospective Analysis. Front Physiol 2021; 12:649901. [PMID: 34054569 PMCID: PMC8155500 DOI: 10.3389/fphys.2021.649901] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 03/17/2021] [Indexed: 01/03/2023] Open
Abstract
OBJECTIVE To characterize the relationship between persistent post-traumatic headache (pPTH) and traumatic cerebrovascular injury (TCVI) in chronic traumatic brain injury (TBI). Cerebrovascular reactivity (CVR), a measure of the cerebral microvasculature and endothelial cell function, is altered both in individuals with chronic TBI and migraine headache disorder (Amyot et al., 2017; Lee et al., 2019b). The pathophysiologies of pPTH and migraine are believed to be associated with chronic microvascular dysfunction. We therefore hypothesize that TCVI may contribute to the underlying migraine-like mechanism(s) of pPTH. MATERIALS AND METHODS 22 moderate/severe TBI participants in the chronic stage (>6 months) underwent anatomic and functional magnetic resonance imaging (fMRI) scanning with hypercapnia gas challenge to measure CVR as well as the change in CVR (ΔCVR) after single-dose treatment of a specific phosphodiesterase-5 (PDE-5) inhibitor, sildenafil, which potentiates vasodilation in response to hypercapnia in impaired endothelium, as part of a Phase2a RCT of sildenafil in chronic TBI (NCT01762475). CVR and ΔCVR measures of each participant were compared with the individual's pPTH severity measured by the headache impact test-6 (HIT-6) survey. RESULTS There was a moderate correlation between HIT-6 and both CVR and ΔCVR scores [Spearman's correlation = -0.50 (p = 0.018) and = 0.46 (p = 0.03), respectively], indicating that a higher headache burden is associated with decreased endothelial function in our chronic TBI population. CONCLUSION There is a correlation between PTH and CVR in chronic moderate-severe TBI. This relationship suggests that chronic TCVI may underlie the pathobiology of pPTH. Further, our results suggest that novel treatment strategies that target endothelial function and vascular health may be beneficial in refractory pPTH.
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Affiliation(s)
- Franck Amyot
- National Intrepid Center of Excellence, Walter Reed National Military Medical Center, Bethesda, MD, United States
| | - Cillian E. Lynch
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - John Ollinger
- National Intrepid Center of Excellence, Walter Reed National Military Medical Center, Bethesda, MD, United States
| | - J. Kent Werner
- Department of Neurology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - E. Silverman
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Carol Moore
- Department of Neurology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Cora Davis
- National Intrepid Center of Excellence, Walter Reed National Military Medical Center, Bethesda, MD, United States
| | - L. Christine Turtzo
- National Institutes of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Ramon Diaz-Arrastia
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Kimbra Kenney
- National Intrepid Center of Excellence, Walter Reed National Military Medical Center, Bethesda, MD, United States
- Department of Neurology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
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12
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Griffin AD, Turtzo LC, Parikh GY, Tolpygo A, Lodato Z, Moses AD, Nair G, Perl DP, Edwards NA, Dardzinski BJ, Armstrong RC, Ray-Chaudhury A, Mitra PP, Latour LL. Traumatic microbleeds suggest vascular injury and predict disability in traumatic brain injury. Brain 2020; 142:3550-3564. [PMID: 31608359 DOI: 10.1093/brain/awz290] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 07/15/2019] [Accepted: 07/28/2019] [Indexed: 12/14/2022] Open
Abstract
Traumatic microbleeds are small foci of hypointensity seen on T2*-weighted MRI in patients following head trauma that have previously been considered a marker of axonal injury. The linear appearance and location of some traumatic microbleeds suggests a vascular origin. The aims of this study were to: (i) identify and characterize traumatic microbleeds in patients with acute traumatic brain injury; (ii) determine whether appearance of traumatic microbleeds predict clinical outcome; and (iii) describe the pathology underlying traumatic microbleeds in an index patient. Patients presenting to the emergency department following acute head trauma who received a head CT were enrolled within 48 h of injury and received a research MRI. Disability was defined using Glasgow Outcome Scale-Extended ≤6 at follow-up. All magnetic resonance images were interpreted prospectively and were used for subsequent analysis of traumatic microbleeds. Lesions on T2* MRI were stratified based on 'linear' streak-like or 'punctate' petechial-appearing traumatic microbleeds. The brain of an enrolled subject imaged acutely was procured following death for evaluation of traumatic microbleeds using MRI targeted pathology methods. Of the 439 patients enrolled over 78 months, 31% (134/439) had evidence of punctate and/or linear traumatic microbleeds on MRI. Severity of injury, mechanism of injury, and CT findings were associated with traumatic microbleeds on MRI. The presence of traumatic microbleeds was an independent predictor of disability (P < 0.05; odds ratio = 2.5). No differences were found between patients with punctate versus linear appearing microbleeds. Post-mortem imaging and histology revealed traumatic microbleed co-localization with iron-laden macrophages, predominately seen in perivascular space. Evidence of axonal injury was not observed in co-localized histopathological sections. Traumatic microbleeds were prevalent in the population studied and predictive of worse outcome. The source of traumatic microbleed signal on MRI appeared to be iron-laden macrophages in the perivascular space tracking a network of injured vessels. While axonal injury in association with traumatic microbleeds cannot be excluded, recognizing traumatic microbleeds as a form of traumatic vascular injury may aid in identifying patients who could benefit from new therapies targeting the injured vasculature and secondary injury to parenchyma.
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Affiliation(s)
- Allison D Griffin
- Center for Neuroscience and Regenerative Medicine, Bethesda, Maryland, USA.,Acute Cerebrovasular Diagnostics Unit of the National Institute of Neurologic Disorders and Stroke, Bethesda, Maryland, USA
| | - L Christine Turtzo
- Acute Cerebrovasular Diagnostics Unit of the National Institute of Neurologic Disorders and Stroke, Bethesda, Maryland, USA
| | - Gunjan Y Parikh
- R. Adams Cowley Shock Trauma Center, Program in Trauma, University of Maryland School of Medicine, Baltimore, USA.,Division of Neurocritical Care and Emergency Neurology, Department of Neurology, University of Maryland School of Medicine, Baltimore, USA
| | | | - Zachary Lodato
- Center for Neuroscience and Regenerative Medicine, Bethesda, Maryland, USA.,Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, USA
| | - Anita D Moses
- Center for Neuroscience and Regenerative Medicine, Bethesda, Maryland, USA.,Acute Cerebrovasular Diagnostics Unit of the National Institute of Neurologic Disorders and Stroke, Bethesda, Maryland, USA
| | - Govind Nair
- National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, USA
| | - Daniel P Perl
- Center for Neuroscience and Regenerative Medicine, Bethesda, Maryland, USA.,Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Nancy A Edwards
- Surgical Neurology Branch of the National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, USA
| | - Bernard J Dardzinski
- Center for Neuroscience and Regenerative Medicine, Bethesda, Maryland, USA.,Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Regina C Armstrong
- Center for Neuroscience and Regenerative Medicine, Bethesda, Maryland, USA.,Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Abhik Ray-Chaudhury
- Surgical Neurology Branch of the National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, USA
| | - Partha P Mitra
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, USA
| | - Lawrence L Latour
- Center for Neuroscience and Regenerative Medicine, Bethesda, Maryland, USA.,Acute Cerebrovasular Diagnostics Unit of the National Institute of Neurologic Disorders and Stroke, Bethesda, Maryland, USA
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13
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Amyot F, Kenney K, Spessert E, Moore C, Haber M, Silverman E, Gandjbakhche A, Diaz-Arrastia R. Assessment of cerebrovascular dysfunction after traumatic brain injury with fMRI and fNIRS. NEUROIMAGE-CLINICAL 2019; 25:102086. [PMID: 31790877 PMCID: PMC6909332 DOI: 10.1016/j.nicl.2019.102086] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 11/07/2019] [Accepted: 11/09/2019] [Indexed: 11/26/2022]
Abstract
Traumatic cerebral vascular injury (TCVI) is a frequent, but under-recognized, endophenotype of traumatic brain injury (TBI). It likely contributes to functional deficits after TBI and TBI-related chronic disability, and represents an attractive target for targeted therapeutic interventions. The aim of this prospective study is to assess microvascular injury/dysfunction in chronic TBI by measuring cerebral vascular reactivity (CVR) by 2 methods, functional magnetic resonance imaging (fMRI) and functional Near InfraRed Spectroscopy (fNIRS) imaging, as each has attractive features relevant to clinical utility. 42 subjects (27 chronic TBI, 15 age- and gender-matched non-TBI volunteers) were enrolled and underwent outpatient CVR testing by 2 methods, MRI-BOLD and fNIRS, each with hypercapnia challenge, a neuropsychological testing battery, and symptom survey questionnaires. Chronic TBI subjects showed a significant reduction in global CVR compared to HC (p < 0.0001). Mean CVR measures by fMRI were 0.225 ± 0.014 and 0.183 ± 0.026 %BOLD/mmHg for non-TBI and TBI subjects respectively and 12.3 ± 1.8 and 9.2 ± 1.7 mM/mmHg by fNIRS for non-TBI versus TBI subjects respectively. Global CVR measured by fNIRS imaging correlates with results by MRI-BOLD (R = 0.5). Focal CVR deficits seen on CVR maps by fMRI are also observed in the same areas by fNIRS in the frontal regions. Global CVR is significantly lower in chronic TBI patients and is reliably measured by both fMRI and fNIRS, the former with better spatial and the latter with better temporal resolution. Both methods show promise as non-invasive measures of CVR function and microvascular integrity after TBI.
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Affiliation(s)
- Franck Amyot
- Department of Neurology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA; Center for Neuroscience and Regenerative Medicine, Department of Neurology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA.
| | - Kimbra Kenney
- Department of Neurology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA; Center for Neuroscience and Regenerative Medicine, Department of Neurology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - Emily Spessert
- Department of Neurology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA; Center for Neuroscience and Regenerative Medicine, Department of Neurology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - Carol Moore
- Department of Neurology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA; Center for Neuroscience and Regenerative Medicine, Department of Neurology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - Margalit Haber
- Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia
| | - Erika Silverman
- Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia
| | - Amir Gandjbakhche
- Section on Analytical and Functional Biophotonics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Ramon Diaz-Arrastia
- Center for Neuroscience and Regenerative Medicine, Department of Neurology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA; Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia
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14
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Sandsmark DK, Bashir A, Wellington CL, Diaz-Arrastia R. Cerebral Microvascular Injury: A Potentially Treatable Endophenotype of Traumatic Brain Injury-Induced Neurodegeneration. Neuron 2019; 103:367-379. [PMID: 31394062 PMCID: PMC6688649 DOI: 10.1016/j.neuron.2019.06.002] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 05/10/2019] [Accepted: 06/03/2019] [Indexed: 02/08/2023]
Abstract
Traumatic brain injury (TBI) is one the most common human afflictions, contributing to long-term disability in survivors. Emerging data indicate that functional improvement or deterioration can occur years after TBI. In this regard, TBI is recognized as risk factor for late-life neurodegenerative disorders. TBI encompasses a heterogeneous disease process in which diverse injury subtypes and multiple molecular mechanisms overlap. To develop precision medicine approaches where specific pathobiological processes are targeted by mechanistically appropriate therapies, techniques to identify and measure these subtypes are needed. Traumatic microvascular injury is a common but relatively understudied TBI endophenotype. In this review, we describe evidence of microvascular dysfunction in human and animal TBI, explore the role of vascular dysfunction in neurodegenerative disease, and discuss potential opportunities for vascular-directed therapies in ameliorating TBI-related neurodegeneration. We discuss the therapeutic potential of vascular-directed therapies in TBI and the use and limitations of preclinical models to explore these therapies.
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Affiliation(s)
| | - Asma Bashir
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada; Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada
| | - Cheryl L Wellington
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada; Djavad Mowafaghian Centre for Brain Health, School of Biomedical Engineering, University of British Columbia, Vancouver, BC, Canada
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15
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Haber M, Amyot F, Kenney K, Meredith-Duliba T, Moore C, Silverman E, Podell J, Chou YY, Pham DL, Butman J, Lu H, Diaz-Arrastia R, Sandsmark D. Vascular Abnormalities within Normal Appearing Tissue in Chronic Traumatic Brain Injury. J Neurotrauma 2018; 35:2250-2258. [PMID: 29609518 DOI: 10.1089/neu.2018.5684] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Abstract
Magnetic resonance imaging (MRI) is a powerful tool for visualizing traumatic brain injury(TBI)-related lesions. Trauma-induced encephalomalacia is frequently identified by its hyperintense appearance on fluid-attenuated inversion recovery (FLAIR) sequences. In addition to parenchymal lesions, TBI commonly results in cerebral microvascular injury, but its anatomical relationship to parenchymal encephalomalacia is not well characterized. The current study utilized a multi-modal MRI protocol to assess microstructural tissue integrity (by mean diffusivity [MD] and fractional aniosotropy [FA]) and altered vascular function (by cerebral blood flow [CBF] and cerebral vascular reactivity [CVR]) within regions of visible encephalomalacia and normal appearing tissue in 27 chronic TBI (minimum 6 months post-injury) subjects. Fifteen subjects had visible encephalomalacias whereas 12 did not have evident lesions on MRI. Imaging from 14 age-matched healthy volunteers were used as controls. CBF was assessed by arterial spin labeling (ASL) and CVR by measuring the change in blood-oxygen-level-dependent (BOLD) MRI during a hypercapnia challenge. There was a significant reduction in FA, CBF, and CVR with a complementary increase in MD within regions of FLAIR-visible encephalomalacia (p < 0.05 for all comparisons). In normal-appearing brain regions, only CVR was significantly reduced relative to controls (p < 0.05). These findings indicate that vascular dysfunction represents a TBI endophenotype that is distinct from structural injury detected using conventional MRI, may be present even in the absence of visible structural injury, and persists long after trauma. CVR may serve as a useful diagnostic and pharmacodynamic imaging biomarker of traumatic microvascular injury.
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Affiliation(s)
- Margalit Haber
- 1 Department of Neurology, University of Pennsylvania Perelman School of Medicine , Philadelphia, Pennsylvania
| | - Franck Amyot
- 6 National Intrepid Center of Excellence, Walter Reed National Military Medical Center, Bethesda, Maryland
| | - Kimbra Kenney
- 2 Department of Neurology, Uniformed Services University of the Health Sciences , Bethesda, Maryland
| | - Tawny Meredith-Duliba
- 1 Department of Neurology, University of Pennsylvania Perelman School of Medicine , Philadelphia, Pennsylvania
| | - Carol Moore
- 2 Department of Neurology, Uniformed Services University of the Health Sciences , Bethesda, Maryland
| | - Erika Silverman
- 1 Department of Neurology, University of Pennsylvania Perelman School of Medicine , Philadelphia, Pennsylvania
| | - Jamie Podell
- 1 Department of Neurology, University of Pennsylvania Perelman School of Medicine , Philadelphia, Pennsylvania
| | - Yi-Yu Chou
- 3 Center for Neuroscience and Regenerative Medicine , Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland
| | - Dzung L Pham
- 3 Center for Neuroscience and Regenerative Medicine , Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland
| | - John Butman
- 4 National Institutes of Health , Clinical Center, Radiology and Imaging Sciences, Bethesda, Maryland
| | - Hanzhang Lu
- 5 Department of Radiology, Johns Hopkins University Baltimore , Maryland
| | - Ramon Diaz-Arrastia
- 1 Department of Neurology, University of Pennsylvania Perelman School of Medicine , Philadelphia, Pennsylvania
| | - Danielle Sandsmark
- 1 Department of Neurology, University of Pennsylvania Perelman School of Medicine , Philadelphia, Pennsylvania
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