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Sarkar C, Lipinski MM. Glycerophospholipid dysregulation after traumatic brain injury. Neurochem Int 2024; 175:105701. [PMID: 38428503 PMCID: PMC11040658 DOI: 10.1016/j.neuint.2024.105701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 02/17/2024] [Accepted: 02/18/2024] [Indexed: 03/03/2024]
Abstract
Brain tissue is highly enriched in lipids, the majority of which are glycerophospholipids. Glycerophospholipids are the major constituents of cellular membranes and play an important role in maintaining integrity and function of cellular and subcellular structures. Any changes in glycerophospholipid homeostasis can adversely affect brain functions. Traumatic brain injury (TBI), an acquired injury caused by the impact of external forces to the brain, triggers activation of secondary biochemical events that include perturbation of lipid homeostasis. Several studies have demonstrated glycerophospholipid dysregulation in the brain and circulation after TBI. This includes spatial and temporal changes in abundance and distribution of glycerophospholipids in the injured brain. This is at least in part mediated by TBI-induced oxidative stress and by activation of lipid metabolism pathways involved in tissue repairing. In this review, we discuss current advances in understanding of the mechanisms and implications of glycerophospholipid dysregulation following TBI.
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Affiliation(s)
- Chinmoy Sarkar
- Shock, Trauma and Anesthesiology Research (STAR) Center, Department of Anesthesiology, Baltimore, MD, 21201, USA.
| | - Marta M Lipinski
- Shock, Trauma and Anesthesiology Research (STAR) Center, Department of Anesthesiology, Baltimore, MD, 21201, USA; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
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2
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Karimy JK, Newville JC, Sadegh C, Morris JA, Monuki ES, Limbrick DD, McAllister Ii JP, Koschnitzky JE, Lehtinen MK, Jantzie LL. Outcomes of the 2019 hydrocephalus association workshop, "Driving common pathways: extending insights from posthemorrhagic hydrocephalus". Fluids Barriers CNS 2023; 20:4. [PMID: 36639792 PMCID: PMC9838022 DOI: 10.1186/s12987-023-00406-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 01/05/2023] [Indexed: 01/15/2023] Open
Abstract
The Hydrocephalus Association (HA) workshop, Driving Common Pathways: Extending Insights from Posthemorrhagic Hydrocephalus, was held on November 4 and 5, 2019 at Washington University in St. Louis. The workshop brought together a diverse group of basic, translational, and clinical scientists conducting research on multiple hydrocephalus etiologies with select outside researchers. The main goals of the workshop were to explore areas of potential overlap between hydrocephalus etiologies and identify drug targets that could positively impact various forms of hydrocephalus. This report details the major themes of the workshop and the research presented on three cell types that are targets for new hydrocephalus interventions: choroid plexus epithelial cells, ventricular ependymal cells, and immune cells (macrophages and microglia).
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Affiliation(s)
- Jason K Karimy
- Department of Family Medicine, Mountain Area Health Education Center - Boone, North Carolina, 28607, USA
| | - Jessie C Newville
- Department of Pediatrics and Neurosurgery, Johns Hopkins Children's Center, Johns Hopkins School of Medicine, Baltimore, MD, 21287, USA
| | - Cameron Sadegh
- Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, MA, Boston, 02114, USA
- Department of Pathology, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Jill A Morris
- National Institute of Neurological Disorders and Stroke, Neuroscience Center, National Institutes of Health, 6001 Executive Blvd, NSC Rm 2112, Bethesda, MD, 20892, USA
| | - Edwin S Monuki
- Departments of Pathology & Laboratory Medicine and Developmental & Cell Biology, University of California Irvine, Irvine, CA, 92697, USA
| | - David D Limbrick
- Departments of Neurosurgery and Pediatrics, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
| | - James P McAllister Ii
- Departments of Neurosurgery and Pediatrics, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
| | | | - Maria K Lehtinen
- Department of Pathology, Boston Children's Hospital, Boston, MA, 02115, USA.
| | - Lauren L Jantzie
- Department of Pediatrics and Neurosurgery, Johns Hopkins Children's Center, Johns Hopkins School of Medicine, Baltimore, MD, 21287, USA.
- Kennedy Krieger Institute, Baltimore, MD, 21287, USA.
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Sato F, Nakamura Y, Ma S, Kochi T, Hisaoka-Nakashima K, Wang D, Liu K, Wake H, Nishibori M, Morioka N. Central high mobility group box-1 induces mechanical hypersensitivity with spinal microglial activation in a mouse model of hemi-Parkinson's disease. Biomed Pharmacother 2021; 145:112479. [PMID: 34915668 DOI: 10.1016/j.biopha.2021.112479] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 11/30/2021] [Accepted: 11/30/2021] [Indexed: 02/07/2023] Open
Abstract
Parkinson's disease (PD) patients often complain of pain, but this problem has been neglected and is poorly understood. High mobility group box-1 (HMGB1), an alarmin/damage-associated molecular patterns protein, is increased in the cerebrospinal fluid in PD patients. However, little is known of the relationship between HMGB1 and pain associated with PD. Here, we investigated the role of central HMGB1 in the regulation of nociceptive hypersensitivity in a mouse model of PD. Male ddY mice were microinjected unilaterally with 6-hydroxydopamine (6OHDA) into the striatum. These hemi-PD mice were treated with anti-HMGB1 neutralizing antibody (nAb; 10 µg in 10 µL) by intranasal (i.n.) administration. The mechanical hypersensitivity of the hind paws was evaluated with the von Frey test. Spinal microglial activity was analyzed by immunostaining for ionized calcium-binding adapter molecule 1. The 6OHDA-administered mice displayed unilateral loss of dopamine neurons in the substantia nigra and mechanical hypersensitivity in both hind paws. Moreover, spinal microglia were activated in these hemi-PD mice. Twenty-eight days after the 6OHDA injections, repeated i.n., but not systemic, treatment with anti-HMGB1 nAb inhibited the bilateral mechanical hypersensitivity and spinal microglial activation. However, the anti-HMGB1 nAb did not ameliorate the dopamine neuron loss. Moreover, intracerebroventricular injection with recombinant HMGB1 induced mechanical hypersensitivity. These findings indicate that HMGB1 is involved in the maintenance of nociceptive symptoms in hemi-PD mice via spinal microglial activation. Therefore, central HMGB1 may have potential as a therapeutic target for pain associated with PD.
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Affiliation(s)
- Fumiaki Sato
- Department of Pharmacology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Japan
| | - Yoki Nakamura
- Department of Pharmacology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Japan.
| | - Simeng Ma
- Department of Pharmacology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Japan
| | - Takahiro Kochi
- Department of Pharmacology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Japan; Department of Dental Anesthesiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Japan
| | - Kazue Hisaoka-Nakashima
- Department of Pharmacology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Japan
| | - Dengli Wang
- Department of Pharmacology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Japan
| | - Keyue Liu
- Department of Pharmacology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Japan
| | - Hidenori Wake
- Department of Pharmacology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Japan; Department of Pharmacology, Faculty of Medicine, Kindai University, Japan
| | - Masahiro Nishibori
- Department of Pharmacology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Japan
| | - Norimitsu Morioka
- Department of Pharmacology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Japan.
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Arun P, Rossetti F, DeMar JC, Wang Y, Batuure AB, Wilder DM, Gist ID, Morris AJ, Sabbadini RA, Long JB. Antibodies Against Lysophosphatidic Acid Protect Against Blast-Induced Ocular Injuries. Front Neurol 2020; 11:611816. [PMID: 33384658 PMCID: PMC7769950 DOI: 10.3389/fneur.2020.611816] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 11/24/2020] [Indexed: 01/18/2023] Open
Abstract
Exposure to blast overpressure waves is implicated as the major cause of ocular injuries and resultant visual dysfunction in veterans involved in recent combat operations. No effective therapeutic strategies have been developed so far for blast-induced ocular dysfunction. Lysophosphatidic acid (LPA) is a bioactive phospholipid generated by activated platelets, astrocytes, choroidal plexus cells, and microglia and is reported to play major roles in stimulating inflammatory processes. The levels of LPA in the cerebrospinal fluid have been reported to increase acutely in patients with traumatic brain injury (TBI) as well as in a controlled cortical impact (CCI) TBI model in mice. In the present study, we have evaluated the efficacy of a single intravenous administration of a monoclonal LPA antibody (25 mg/kg) given at 1 h post-blast for protection against injuries to the retina and associated ocular dysfunctions. Our results show that a single 19 psi blast exposure significantly increased the levels of several species of LPA in blood plasma at 1 and 4 h post-blast. The anti-LPA antibody treatment significantly decreased glial cell activation and preserved neuronal cell morphology in the retina on day 8 after blast exposure. Optokinetic measurements indicated that anti-LPA antibody treatment significantly improved visual acuity in both eyes on days 2 and 6 post-blast exposure. Anti-LPA antibody treatment significantly increased rod photoreceptor and bipolar neuronal cell signaling in both eyes on day 7 post-blast exposure. These results suggest that blast exposure triggers release of LPAs, which play a major role promoting blast-induced ocular injuries, and that a single early administration of anti-LPA antibodies provides significant protection.
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Affiliation(s)
- Peethambaran Arun
- Blast-Induced Neurotrauma Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Franco Rossetti
- Blast-Induced Neurotrauma Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - James C DeMar
- Blast-Induced Neurotrauma Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Ying Wang
- Blast-Induced Neurotrauma Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Andrew B Batuure
- Blast-Induced Neurotrauma Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Donna M Wilder
- Blast-Induced Neurotrauma Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Irene D Gist
- Blast-Induced Neurotrauma Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Andrew J Morris
- Division of Cardiovascular Medicine, Lexington VA Medical Center, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Roger A Sabbadini
- Department of Biology, San Diego State University, San Diego, CA, United States
| | - Joseph B Long
- Blast-Induced Neurotrauma Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States
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Inoue D, Furubayashi T, Tanaka A, Sakane T, Sugano K. Effect of Cerebrospinal Fluid Circulation on Nose-to-Brain Direct Delivery and Distribution of Caffeine in Rats. Mol Pharm 2020; 17:4067-4076. [PMID: 32955898 DOI: 10.1021/acs.molpharmaceut.0c00495] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Direct drug delivery from nose to brain has drawn much attention as an effective strategy for the treatment of central nervous system diseases. After intranasal administration, drug molecules can be directly delivered from the nose to the brain. However, the detailed mechanism for this direct delivery to the brain has not been elucidated. In the present study, the effect of the activation of the cerebral fluid circulation (the glymphatic system) on the efficacy of direct delivery from nose to brain was investigated. Because the glymphatic system is activated by some anesthetic regimens, the differences in brain delivery and the pharmacokinetics under anesthetic and conscious conditions were compared in rats. Under urethane anesthesia, direct delivery from the nose to the brain was facilitated, whereas the brain uptake from the systemic circulation via the blood-brain barrier was decreased. In addition, both the brain uptake of caffeine injected into the subarachnoid cerebrospinal fluid (CSF) and the extracerebral clearance of caffeine after intrastriatal injection were enhanced under anesthesia. For intranasal administration, caffeine was transported directly from the nose to the CSF and then delivered into the brain parenchyma by the CSF circulation. The results obtained in the present study clarified that the direct delivery from nose to brain could be facilitated by anesthesia. These findings suggest that fluid circulation in the brain can contribute to a wider cerebral distribution of the drug after direct delivery from nose to brain.
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Affiliation(s)
- Daisuke Inoue
- Molecular Pharmaceutics Laboratory, College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga 525-8577, Japan.,Department of Pharmaceutics, School of Pharmacy, Shujitsu University, 1-6-1 Nishigawara, Naka-ku, Okayama 703-8516, Japan
| | - Tomoyuki Furubayashi
- Department of Pharmaceutics, School of Pharmacy, Shujitsu University, 1-6-1 Nishigawara, Naka-ku, Okayama 703-8516, Japan.,Laboratory of Pharmaceutical Technology, Kobe Pharmaceutical University, 4-19-1 Motoyamakita-machi, Higashinada, Kobe 658-8558, Japan
| | - Akiko Tanaka
- Laboratory of Pharmaceutical Technology, Kobe Pharmaceutical University, 4-19-1 Motoyamakita-machi, Higashinada, Kobe 658-8558, Japan
| | - Toshiyasu Sakane
- Laboratory of Pharmaceutical Technology, Kobe Pharmaceutical University, 4-19-1 Motoyamakita-machi, Higashinada, Kobe 658-8558, Japan
| | - Kiyohiko Sugano
- Molecular Pharmaceutics Laboratory, College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga 525-8577, Japan
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Plastira I, Joshi L, Bernhart E, Schoene J, Specker E, Nazare M, Sattler W. Small-Molecule Lysophosphatidic Acid Receptor 5 (LPAR5) Antagonists: Versatile Pharmacological Tools to Regulate Inflammatory Signaling in BV-2 Microglia Cells. Front Cell Neurosci 2019; 13:531. [PMID: 31849616 PMCID: PMC6897279 DOI: 10.3389/fncel.2019.00531] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 11/15/2019] [Indexed: 12/30/2022] Open
Abstract
Lysophosphatidic acid (LPA) species in the extracellular environment induce downstream signaling via six different G protein-coupled receptors (LPAR1–6). These signaling cascades are essential for normal brain development and function of the nervous system. However, in response to acute or chronic central nervous system (CNS) damage, LPA levels increase and aberrant signaling events can counteract brain function. Under neuro-inflammatory conditions signaling along the LPA/LPAR5 axis induces a potentially neurotoxic microglia phenotype indicating the need for new pharmacological intervention strategies. Therefore, we compared the effects of two novel small-molecule LPAR5 antagonists on LPA-induced polarization parameters of the BV-2 microglia cell line. AS2717638 is a selective piperidine-based LPAR5 antagonist (IC50 0.038 μM) while compound 3 is a diphenylpyrazole derivative with an IC50 concentration of 0.7 μM in BV-2 cells. Both antagonists compromised cell viability, however, at concentrations above their IC50 concentrations. Both inhibitors blunted LPA-induced phosphorylation of STAT1 and STAT3, p65, and c-Jun and consequently reduced the secretion of pro-inflammatory cyto-/chemokines (IL-6, TNFα, IL-1β, CXCL10, CXCL2, and CCL5) at non-toxic concentrations. Both compounds modulated the expression of intracellular (COX-2 and Arg1) and plasma membrane-located (CD40, CD86, and CD206) polarization markers yet only AS2717638 attenuated the neurotoxic potential of LPA-activated BV-2 cell-conditioned medium towards CATH.a neurons. Our findings from the present in vitro study suggest that the two LPAR5 antagonists represent valuable pharmacological tools to interfere with LPA-induced pro-inflammatory signaling cascades in microglia.
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Affiliation(s)
- Ioanna Plastira
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Lisha Joshi
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Eva Bernhart
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Jens Schoene
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Edgar Specker
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Marc Nazare
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany.,Berlin Institute of Health (BIH), Charite & MDC, Berlin, Germany
| | - Wolfgang Sattler
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria.,Center for Explorative Lipidomics, BioTechMed-Graz, Graz, Austria
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Xu Y. Targeting Lysophosphatidic Acid in Cancer: The Issues in Moving from Bench to Bedside. Cancers (Basel) 2019; 11:cancers11101523. [PMID: 31658655 PMCID: PMC6826372 DOI: 10.3390/cancers11101523] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 10/02/2019] [Accepted: 10/08/2019] [Indexed: 12/16/2022] Open
Abstract
Since the clear demonstration of lysophosphatidic acid (LPA)'s pathological roles in cancer in the mid-1990s, more than 1000 papers relating LPA to various types of cancer were published. Through these studies, LPA was established as a target for cancer. Although LPA-related inhibitors entered clinical trials for fibrosis, the concept of targeting LPA is yet to be moved to clinical cancer treatment. The major challenges that we are facing in moving LPA application from bench to bedside include the intrinsic and complicated metabolic, functional, and signaling properties of LPA, as well as technical issues, which are discussed in this review. Potential strategies and perspectives to improve the translational progress are suggested. Despite these challenges, we are optimistic that LPA blockage, particularly in combination with other agents, is on the horizon to be incorporated into clinical applications.
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Affiliation(s)
- Yan Xu
- Department of Obstetrics and Gynecology, Indiana University School of Medicine, 950 W. Walnut Street R2-E380, Indianapolis, IN 46202, USA.
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Liang J, Wu S, Xie W, He H. Ketamine ameliorates oxidative stress-induced apoptosis in experimental traumatic brain injury via the Nrf2 pathway. DRUG DESIGN DEVELOPMENT AND THERAPY 2018; 12:845-853. [PMID: 29713142 PMCID: PMC5907785 DOI: 10.2147/dddt.s160046] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Background Ketamine can act as a multifunctional neuroprotective agent by inhibiting oxidative stress, cellular dysfunction, and apoptosis. Although it has been proven to be effective in various neurologic disorders, the mechanism of the treatment of traumatic brain injury (TBI) is not fully understood. The aim of this study was to investigate the neuroprotective function of ketamine in models of TBI and the potential role of the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway in this putative protective effect. Materials and methods Wild-type male mice were randomly assigned to five groups: Sham group, Sham + ketamine group, TBI group, TBI + vehicle group, and TBI + ketamine group. Marmarou’s weight drop model in mice was used to induce TBI, after which either ketamine or vehicle was administered via intraperitoneal injection. After 24 h, the brain samples were collected for analysis. Results Ketamine significantly ameliorated secondary brain injury induced by TBI, including neurological deficits, brain water content, and neuronal apoptosis. In addition, the levels of malondialdehyde (MDA), glutathione peroxidase (GPx), and superoxide dismutase (SOD) were restored by the ketamine treatment. Western blotting and immunohistochemistry showed that ketamine significantly increased the level of Nrf2. Furthermore, administration of ketamine also induced the expression of Nrf2 pathway-related downstream factors, including hemeoxygenase-1 and quinine oxidoreductase-1, at the pre- and post-transcriptional levels. Conclusion Ketamine exhibits neuroprotective effects by attenuating oxidative stress and apoptosis after TBI. Therefore, ketamine could be an effective therapeutic agent for the treatment of TBI.
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Affiliation(s)
- Jinwei Liang
- Department of Anesthesiology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian Province, People's Republic of China
| | - Shanhu Wu
- Department of Anesthesiology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian Province, People's Republic of China
| | - Wenxi Xie
- Department of Anesthesiology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian Province, People's Republic of China
| | - Hefan He
- Department of Anesthesiology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian Province, People's Republic of China
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Meidahl AC, Eisenried A, Klukinov M, Cao L, Tzabazis AZ, Yeomans DC. Intranasal Oxytocin Attenuates Reactive and Ongoing, Chronic Pain in a Model of Mild Traumatic Brain Injury. Headache 2017; 58:545-558. [PMID: 29266199 DOI: 10.1111/head.13248] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/05/2017] [Indexed: 11/30/2022]
Abstract
BACKGROUND Approximately 1.7 million Americans sustain a traumatic brain injury (TBI) each year and chronic pain is a common complication. OBJECTIVE We studied the effects of intranasally administered oxytocin as a potential treatment for chronic pain in an animal model of mild TBI. METHODS The lateral fluid percussion model of mild TBI was chosen for this purpose and after exposure to mild TBI the rats (n = 12) developed hind paw and facial allodynia compared to sham animals (n = 6). Oxytocin or a vehicle was afterwards administered intranasally and reactive pain was assessed by hind paw and facial von Frey testing. Some animals received the oxytocin receptor antagonist, atosiban, in addition to oxytocin/vehicle treatment (n = 12). The effect of oxytocin on ongoing and spontaneous pain was examined through conditioned place preference testing. To determine whether the effects of intranasal oxytocin could be attributed to delivery via the peripheral blood stream, some TBI animals received an intravenous injection of the same oxytocin dose that was given intranasally. ELISA immunoassays were carried out (n = 6) to measure concentrations of oxytocin in the trigeminal ganglia, pons, spinal cord, and olfactory bulb after intranasal administration and evaluate the most likely route of entry. RESULTS These studies confirmed that the fluid percussion model can be used to study post-TBI facial allodynia. Oxytocin attenuated both reactive and spontaneous, ongoing non-reactive pain following mild TBI for at least 3-4 hours after intranasal administration by binding to OT or VA1-receptors most likely by a peri-trigeminal nerve mediated uptake. CONCLUSIONS Intranasal oxytocin attenuates measures of reactive and non-reactive pain in a model of mild TBI and may represent a novel treatment for chronic pain in TBI patients.
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Affiliation(s)
- Anders C Meidahl
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, School of Medicine, Stanford, CA, USA
| | - Andreas Eisenried
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, School of Medicine, Stanford, CA, USA
| | - Michael Klukinov
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, School of Medicine, Stanford, CA, USA
| | - Longhui Cao
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, School of Medicine, Stanford, CA, USA
| | - Alexander Z Tzabazis
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, School of Medicine, Stanford, CA, USA
| | - David C Yeomans
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, School of Medicine, Stanford, CA, USA
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