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Heavener K, Kabra K, Yidenk M, Bradshaw E. IL-1RA Disrupts ATP Activation of P2RX7 in Human Monocyte-Derived Microglia-like Cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.08.588607. [PMID: 38645234 PMCID: PMC11030313 DOI: 10.1101/2024.04.08.588607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
The immune system has a dynamic role in neurodegenerative diseases, and purinergic receptors allow immune cells to recognize neuronal signaling, cell injury, or stress. Purinergic Receptor 7 (P2RX7) can modulate inflammatory cascades and its expression is upregulated in Alzheimer's disease (AD) brain tissue. P2RX7 expression is enriched in microglia, and elevated levels are found in microglia surrounding amyloid-beta plaques in the brain. While P2RX7 is thought to play a role in neurodegenerative diseases, how it modulates pathology and disease progression is not well understood. Here, we utilize a human monocyte-derived microglia-like cell (MDMi) model to interrogate P2RX7 activation and downstream consequences on microglia function. By using MDMi derived from human donors, we can examine how human donor variation impacts microglia function. We assessed P2RX7-driven IL1β and IL18 production and amyloid-beta peptide 1-42 (Aβ1-42) uptake levels. Our results show that ATP-stimulation of MDMi triggers upregulation of IL1β and IL18 expression. This upregulation of cytokine gene expression is blocked with the A740003 P2RX7 antagonist. We find that high extracellular ATP conditions also reduced MDMi capacity for Aβ1-42 uptake, and this loss of function is prevented through A740003 inhibition of P2RX7. In addition, pretreatment of MDMi with IL-1RA limited ATP-driven IL1β and IL18 gene expression upregulation, indicating that ATP immunomodulation of P2RX7 is IL-1R dependent. Aβ1-42 uptake was higher with IL-1RA pretreatment compared to ATP treatment alone, suggesting P2RX7 regulates phagocytic engulfment through IL-1 signaling. Overall, our results demonstrate that P2RX7 is a key response protein for high extracellular ATP in human microglia-like cells, and its function can be modulated by IL-1 signaling. This work opens the door to future studies examining anti-IL-1 biologics to increase the clearance of amyloid-beta.
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Affiliation(s)
- Kelsey Heavener
- Division of Translational Neurobiology, Departments of Neurology Columbia University Medical Center, 630 West 168th Street, New York, NY 10032, USA
- The Carol and Gene Ludwig Center for Research on Neurodegeneration, Departments of Neurology Columbia University Medical Center, 630 West 168th Street, New York, NY 10032, USA
| | - Khushbu Kabra
- Division of Translational Neurobiology, Departments of Neurology Columbia University Medical Center, 630 West 168th Street, New York, NY 10032, USA
- The Carol and Gene Ludwig Center for Research on Neurodegeneration, Departments of Neurology Columbia University Medical Center, 630 West 168th Street, New York, NY 10032, USA
| | - Maedot Yidenk
- Division of Translational Neurobiology, Departments of Neurology Columbia University Medical Center, 630 West 168th Street, New York, NY 10032, USA
- The Carol and Gene Ludwig Center for Research on Neurodegeneration, Departments of Neurology Columbia University Medical Center, 630 West 168th Street, New York, NY 10032, USA
| | - Elizabeth Bradshaw
- Division of Translational Neurobiology, Departments of Neurology Columbia University Medical Center, 630 West 168th Street, New York, NY 10032, USA
- The Carol and Gene Ludwig Center for Research on Neurodegeneration, Departments of Neurology Columbia University Medical Center, 630 West 168th Street, New York, NY 10032, USA
- Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, Departments of Neurology Columbia University Medical Center, 630 West 168th Street, New York, NY 10032, USA
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O'Brien JA, Karrasch JF, Huang Y, Vine EE, Cunningham AL, Harman AN, Austin PJ. Nerve-myeloid cell interactions in persistent human pain: a reappraisal using updated cell subset classifications. Pain 2024; 165:753-771. [PMID: 37975868 DOI: 10.1097/j.pain.0000000000003106] [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: 03/03/2023] [Accepted: 09/04/2023] [Indexed: 11/19/2023]
Abstract
ABSTRACT The past 20 years have seen a dramatic shift in our understanding of the role of the immune system in initiating and maintaining pain. Myeloid cells, including macrophages, dendritic cells, Langerhans cells, and mast cells, are increasingly implicated in bidirectional interactions with nerve fibres in rodent pain models. However, our understanding of the human setting is still poor. High-dimensional functional analyses have substantially changed myeloid cell classifications, with recently described subsets such as epidermal dendritic cells and DC3s unveiling new insight into how myeloid cells interact with nerve fibres. However, it is unclear whether this new understanding has informed the study of human chronic pain. In this article, we perform a scoping review investigating neuroimmune interactions between myeloid cells and peripheral nerve fibres in human chronic pain conditions. We found 37 papers from multiple pain states addressing this aim in skin, cornea, peripheral nerve, endometrium, and tumour, with macrophages, Langerhans cells, and mast cells the most investigated. The directionality of results between studies was inconsistent, although the clearest pattern was an increase in macrophage frequency across conditions, phases, and tissues. Myeloid cell definitions were often outdated and lacked correspondence with the stated cell types of interest; overreliance on morphology and traditional structural markers gave limited insight into the functional characteristics of investigated cells. We therefore critically reappraise the existing literature considering contemporary myeloid cell biology and advocate for the application of established and emerging high-dimensional proteomic and transcriptomic single-cell technologies to clarify the role of specific neuroimmune interactions in chronic pain.
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Affiliation(s)
- Jayden A O'Brien
- Brain and Mind Centre, The University of Sydney, Sydney, Australia
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, Australia
| | - Jackson F Karrasch
- Brain and Mind Centre, The University of Sydney, Sydney, Australia
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, Australia
- Centre for Virus Research, The Westmead Institute for Medical Research, Westmead, Australia
| | - Yun Huang
- Brain and Mind Centre, The University of Sydney, Sydney, Australia
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, Australia
| | - Erica E Vine
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, Australia
- Centre for Virus Research, The Westmead Institute for Medical Research, Westmead, Australia
| | - Anthony L Cunningham
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, Australia
- Centre for Virus Research, The Westmead Institute for Medical Research, Westmead, Australia
| | - Andrew N Harman
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, Australia
- Centre for Virus Research, The Westmead Institute for Medical Research, Westmead, Australia
| | - Paul J Austin
- Brain and Mind Centre, The University of Sydney, Sydney, Australia
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, Australia
- Centre for Virus Research, The Westmead Institute for Medical Research, Westmead, Australia
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3
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The Fetal Type of Posterior Cerebral Artery. MEDICINA (KAUNAS, LITHUANIA) 2023; 59:medicina59020231. [PMID: 36837433 PMCID: PMC9961316 DOI: 10.3390/medicina59020231] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Revised: 01/18/2023] [Accepted: 01/24/2023] [Indexed: 01/28/2023]
Abstract
Background and Objectives: Anatomical variations of the arterial circle of Willis (cW) are common. A posterior cerebral artery (PCA) fed mostly or exclusively from the internal carotid artery is a fetal PCA (FPCA), partial (p-FPCA), or full/complete (f-FPCA), respectively. Because FPCA occurs in different anatomical configurations of the cW sides, we aimed to document in detail these morphological possibilities of FPCA within the cW. Materials and Methods: FPCAs were documented on a retrospective set of 139 computed tomography angiograms. Results: FPCAs were found in thirteen cases, nine males and four females. In 7/13 cases there were two modified sides of the cW. In 5/13 cases there were three altered sides of the cW. Another case with FPCA showed four altered sides of the cW. In 10/13 cases, FPCA was unilateral and in the other three cases it was bilateral. Compared to the overall group, unilateral p-FPCAs were found in 1.43%, while unilateral f-FPCAs were found in 5.75%. A bilateral p-FPCA-f-FPCA combination was found in 0.71% and a bilateral f-FPCA-f-FPCA combination occurred in 1.43%. An anatomically isolated ICA was found in just one case with bilateral f-FPCA (0.71%). In 7/13 FPCA cases there were arterial variants exclusively in the posterior cW. In the other 6/13 FPCA cases, there were variants in both anterior and posterior circulation. There were no statistically significant associations of FPCA with sex or age. The higher prevalence of right-sided FPCA was not statistically significant. Conclusions: Anatomical assessments of cW should be performed on a case-by-case basis, as they may correspond to different cW morphologies.
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Krishnagopal S, Lohse K, Braun R. Stroke recovery phenotyping through network trajectory approaches and graph neural networks. Brain Inform 2022; 9:13. [PMID: 35717640 PMCID: PMC9206968 DOI: 10.1186/s40708-022-00160-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 04/23/2022] [Indexed: 11/23/2022] Open
Abstract
Stroke is a leading cause of neurological injury characterized by impairments in multiple neurological domains including cognition, language, sensory and motor functions. Clinical recovery in these domains is tracked using a wide range of measures that may be continuous, ordinal, interval or categorical in nature, which can present challenges for multivariate regression approaches. This has hindered stroke researchers’ ability to achieve an integrated picture of the complex time-evolving interactions among symptoms. Here, we use tools from network science and machine learning that are particularly well-suited to extracting underlying patterns in such data, and may assist in prediction of recovery patterns. To demonstrate the utility of this approach, we analyzed data from the NINDS tPA trial using the Trajectory Profile Clustering (TPC) method to identify distinct stroke recovery patterns for 11 different neurological domains at 5 discrete time points. Our analysis identified 3 distinct stroke trajectory profiles that align with clinically relevant stroke syndromes, characterized both by distinct clusters of symptoms, as well as differing degrees of symptom severity. We then validated our approach using graph neural networks to determine how well our model performed predictively for stratifying patients into these trajectory profiles at early vs. later time points post-stroke. We demonstrate that trajectory profile clustering is an effective method for identifying clinically relevant recovery subtypes in multidimensional longitudinal datasets, and for early prediction of symptom progression subtypes in individual patients. This paper is the first work introducing network trajectory approaches for stroke recovery phenotyping, and is aimed at enhancing the translation of such novel computational approaches for practical clinical application.
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Affiliation(s)
- Sanjukta Krishnagopal
- Gatsby Computational Neuroscience Unit, University College London, London, W1T 4JG, UK.
| | - Keith Lohse
- Physical Therapy and Neurology, Washington University School of Medicine, 4444 Forest Park Ave., Suite 1101, St. Louis, MO, 63108-2212, USA
| | - Robynne Braun
- Department of Neurology, University of Maryland School of Medicine, 655 W. Baltimore Street, Bressler Research Building, 12th Floor, Baltimore, MD, 21201, USA, on behalf of the GPAS Collaboration, Phenotyping Core
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5
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Gong B, Zhang X, Zahrani AA, Gao W, Ma G, Zhang L, Xue J. Neural tissue engineering: From bioactive scaffolds and in situ monitoring to regeneration. EXPLORATION (BEIJING, CHINA) 2022; 2:20210035. [PMID: 37323703 PMCID: PMC10190951 DOI: 10.1002/exp.20210035] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Accepted: 03/09/2022] [Indexed: 06/17/2023]
Abstract
Peripheral nerve injury is a large-scale problem that annually affects more than several millions of people all over the world. It remains a great challenge to effectively repair nerve defects. Tissue engineered nerve guidance conduits (NGCs) provide a promising platform for peripheral nerve repair through the integration of bioactive scaffolds, biological effectors, and cellular components. Herein, we firstly describe the pathogenesis of peripheral nerve injuries at different orders of severity to clarify their microenvironments and discuss the clinical treatment methods and challenges. Then, we discuss the recent progress on the design and construction of NGCs in combination with biological effectors and cellular components for nerve repair. Afterward, we give perspectives on imaging the nerve and/or the conduit to allow for the in situ monitoring of the nerve regeneration process. We also cover the applications of different postoperative intervention treatments, such as electric field, magnetic field, light, and ultrasound, to the well-designed conduit and/or the nerve for improving the repair efficacy. Finally, we explore the prospects of multifunctional platforms to promote the repair of peripheral nerve injury.
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Affiliation(s)
- Bowen Gong
- Beijing Laboratory of Biomedical MaterialsBeijing University of Chemical TechnologyBeijingChina
- State Key Laboratory of Organic–Inorganic CompositesBeijing University of Chemical TechnologyBeijingChina
| | - Xindan Zhang
- Beijing Laboratory of Biomedical MaterialsBeijing University of Chemical TechnologyBeijingChina
- State Key Laboratory of Organic–Inorganic CompositesBeijing University of Chemical TechnologyBeijingChina
| | - Ahmed Al Zahrani
- Department of Mechanical and Materials EngineeringUniversity of JeddahJeddahSaudi Arabia
| | - Wenwen Gao
- Department of RadiologyChina–Japan Friendship HospitalBeijingChina
| | - Guolin Ma
- Department of RadiologyChina–Japan Friendship HospitalBeijingChina
| | - Liqun Zhang
- Beijing Laboratory of Biomedical MaterialsBeijing University of Chemical TechnologyBeijingChina
- State Key Laboratory of Organic–Inorganic CompositesBeijing University of Chemical TechnologyBeijingChina
| | - Jiajia Xue
- Beijing Laboratory of Biomedical MaterialsBeijing University of Chemical TechnologyBeijingChina
- State Key Laboratory of Organic–Inorganic CompositesBeijing University of Chemical TechnologyBeijingChina
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6
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Ford ZK, Reker AN, Chen S, Kadakia F, Bunk A, Davidson S. Cannabinoid Receptor 1 Expression in Human Dorsal Root Ganglia and CB13-Induced Bidirectional Modulation of Sensory Neuron Activity. FRONTIERS IN PAIN RESEARCH 2022; 2:721332. [PMID: 35295508 PMCID: PMC8915700 DOI: 10.3389/fpain.2021.721332] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 10/08/2021] [Indexed: 12/23/2022] Open
Abstract
Cannabinoid receptors have been identified as potential targets for analgesia from studies on animal physiology and behavior, and from human clinical trials. Here, we sought to improve translational understanding of the mechanisms of cannabinoid-mediated peripheral analgesia. Human lumbar dorsal root ganglia were rapidly recovered from organ donors to perform physiological and anatomical investigations into the potential for cannabinoids to mediate analgesia at the level of the peripheral nervous system. Anatomical characterization of in situ gene expression and immunoreactivity showed that 61 and 53% of human sensory neurons express the CB1 gene and receptor, respectively. Calcium influx evoked by the algogen capsaicin was measured by Fura-2AM in dissociated human sensory neurons pre-exposed to the inflammatory mediator prostaglandin E2 (PGE2) alone or together with CB13 (1 μM), a cannabinoid agonist with limited blood–brain barrier permeability. Both a higher proportion of neurons and a greater magnitude of response to capsaicin were observed after exposure to CB13, indicating cannabinoid-mediated sensitization. In contrast, membrane properties measured by patch-clamp electrophysiology demonstrated that CB13 suppressed excitability and reduced action potential discharge in PGE2-pre-incubated sensory neurons, suggesting the suppression of sensitization. This bidirectional modulation of sensory neuron activity suggests that cannabinoids may suppress overall membrane excitability while simultaneously enhancing responsivity to TRPV1-mediated stimuli. We conclude that peripherally restricted cannabinoids may have both pro- and anti-nociceptive effects in human sensory neurons.
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Affiliation(s)
- Zachary K Ford
- Neuroscience Graduate Program, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - Ashlie N Reker
- Department of Anesthesiology and Pain Research Center, University of Cincinnati, College of Medicine, Cincinnati, OH, United States
| | - Sisi Chen
- Department of Anesthesiology and Pain Research Center, University of Cincinnati, College of Medicine, Cincinnati, OH, United States
| | - Feni Kadakia
- Neuroscience Graduate Program, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - Alexander Bunk
- Neuroscience Graduate Program, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - Steve Davidson
- Neuroscience Graduate Program, College of Medicine, University of Cincinnati, Cincinnati, OH, United States.,Department of Anesthesiology and Pain Research Center, University of Cincinnati, College of Medicine, Cincinnati, OH, United States
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7
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Balogh M, Janjic JM, Shepherd AJ. Targeting Neuroimmune Interactions in Diabetic Neuropathy with Nanomedicine. Antioxid Redox Signal 2022; 36:122-143. [PMID: 34416821 PMCID: PMC8823248 DOI: 10.1089/ars.2021.0123] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Significance: Diabetes is a major source of neuropathy and neuropathic pain that is set to continue growing in prevalence. Diabetic peripheral neuropathy (DPN) and pain associated with diabetes are not adequately managed by current treatment regimens. Perhaps the greatest difficulty in treating DPN is the complex pathophysiology, which involves aspects of metabolic disruption and neurotrophic deficits, along with neuroimmune interactions. There is, therefore, an urgent need to pursue novel therapeutic options targeting the key cellular and molecular players. Recent Advances: To that end, cellular targeting becomes an increasingly compelling drug delivery option as our knowledge of neuroimmune interactions continues to mount. These nanomedicine-based approaches afford a potentially unparalleled specificity and longevity of drug targeting, using novel or established compounds, all while minimizing off-target effects. Critical Issues: The DPN therapeutics directly targeted at the nervous system make up the bulk of currently available treatment options. However, there are significant opportunities based on the targeting of non-neuronal cells and neuroimmune interactions in DPN. Future Directions: Nanomedicine-based agents represent an exciting opportunity for the treatment of DPN with the goals of improving the efficacy and safety profile of analgesia, as well as restoring peripheral neuroregenerative capacity. Antioxid. Redox Signal. 36, 122-143.
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Affiliation(s)
- Mihály Balogh
- Division of Internal Medicine, Department of Symptom Research, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Jelena M Janjic
- Graduate School of Pharmaceutical Sciences, School of Pharmacy, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Andrew J Shepherd
- Division of Internal Medicine, Department of Symptom Research, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
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8
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Ruel HLM, Watanabe R, Evangelista MC, Beauchamp G, Auger JP, Segura M, Steagall PV. Pain burden, sensory profile and inflammatory cytokines of dogs with naturally-occurring neuropathic pain treated with gabapentin alone or with meloxicam. PLoS One 2020; 15:e0237121. [PMID: 33253197 PMCID: PMC7703878 DOI: 10.1371/journal.pone.0237121] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 11/10/2020] [Indexed: 11/20/2022] Open
Abstract
Canine neuropathic pain (NeuP) has been poorly investigated. This study aimed to evaluate the pain burden, sensory profile and inflammatory cytokines in dogs with naturally-occurring NeuP. Twenty-nine client-owned dogs with NeuP were included in a prospective, partially masked, randomized crossover clinical trial, and treated with gabapentin/placebo/gabapentin-meloxicam or gabapentin-meloxicam/placebo/gabapentin (each treatment block of 7 days; total 21 days). Pain scores, mechanical (MNT) and electrical (ENT) nociceptive thresholds and descending noxious inhibitory controls (DNIC) were assessed at baseline, days 7, 14, and 21. DNIC was evaluated using ΔMNT (after-before conditioning stimulus). Positive or negative ΔMNT corresponded to inhibitory or facilitatory pain profiles, respectively. Pain scores were recorded using the Client Specific Outcome Measures (CSOM), Canine Brief Pain Inventory (CBPI), and short-form Glasgow Composite Measure Pain Scale (CMPS-SF). Data from baseline were compared to those of sixteen healthy controls. ΔMNT, but not MNT and ENT, was significantly larger in controls (2.3 ± 0.9 N) than in NeuP (-0.2 ± 0.7 N). The percentage of dogs with facilitatory sensory profile was similar at baseline and after placebo (61.5–63%), and between controls and after gabapentin (33.3–34.6%). The CBPI scores were significantly different between gabapentin (CBPI pain and CBPI overall impression) and/or gabapentin-meloxicam (CBPI pain and interference) when compared with baseline, but not placebo. The CBPI scores were not significantly different between placebo and baseline. The concentration of cytokines was not different between groups or treatments. Dogs with NeuP have deficient inhibitory pain mechanisms. Pain burden was reduced after gabapentin and/or gabapentin-meloxicam when compared with baseline using CBPI and CMPS-SF scores. However, these scores were not superior than placebo, nor placebo was superior to baseline evaluations. A caregiver placebo effect may have biased the results.
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Affiliation(s)
- Hélène L. M. Ruel
- Department of Clinical Sciences, Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada
| | - Ryota Watanabe
- Department of Clinical Sciences, Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada
| | - Marina C. Evangelista
- Department of Clinical Sciences, Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada
| | - Guy Beauchamp
- Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada
| | - Jean-Philippe Auger
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Centre (CRIPA), Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada
| | - Mariela Segura
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Centre (CRIPA), Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada
| | - Paulo V. Steagall
- Department of Clinical Sciences, Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada
- * E-mail:
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9
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Ultramicronized Palmitoylethanolamide and Paracetamol, a New Association to Relieve Hyperalgesia and Pain in a Sciatic Nerve Injury Model in Rat. Int J Mol Sci 2020; 21:ijms21103509. [PMID: 32429243 PMCID: PMC7278943 DOI: 10.3390/ijms21103509] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 05/12/2020] [Accepted: 05/13/2020] [Indexed: 12/20/2022] Open
Abstract
Inflammation is known to be an essential trigger of the pathological changes that have a critical impact on nerve repair and regeneration; moreover, damage to peripheral nerves can cause a loss of sensory function and produces persistent neuropathic pain. To date, various potential approaches for neuropathic pain have focused on controlling neuroinflammation. The aim of this study was to investigate the neuroprotective effects of a new association of ultramicronized Palmitoylethanolamide (PEAum), an Autacoid Local Injury Antagonist Amide (ALIAmide) with analgesic and anti-inflammatory properties, with Paracetamol, a common analgesic, in a rat model of sciatic nerve injury (SNI). The association of PEAum-Paracetamol, in a low dose (5 mg/kg + 30 mg/kg), was given by oral gavage daily for 14 days after SNI. PEAum-Paracetamol association was able to reduce hyperalgesia, mast cell activation, c-Fos and nerve growth factor (NGF) expression, neural histological damage, cytokine release, and apoptosis. Furthermore, the analgesic action of PEAum-Paracetamol could act in a synergistic manner through the inhibition of the NF-κB pathway, which leads to a decrease of cyclooxygenase 2-dependent prostaglandin E2 (COX-2/PGE2) release. In conclusion, we demonstrated that PEAum associated with Paracetamol was able to relieve pain and neuroinflammation after SNI in a synergistic manner, and this therapeutic approach could be relevant to decrease the demand of analgesic drugs.
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10
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Jang Y, Kim M, Hwang SW. Molecular mechanisms underlying the actions of arachidonic acid-derived prostaglandins on peripheral nociception. J Neuroinflammation 2020; 17:30. [PMID: 31969159 PMCID: PMC6975075 DOI: 10.1186/s12974-020-1703-1] [Citation(s) in RCA: 101] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 01/06/2020] [Indexed: 12/30/2022] Open
Abstract
Arachidonic acid-derived prostaglandins not only contribute to the development of inflammation as intercellular pro-inflammatory mediators, but also promote the excitability of the peripheral somatosensory system, contributing to pain exacerbation. Peripheral tissues undergo many forms of diseases that are frequently accompanied by inflammation. The somatosensory nerves innervating the inflamed areas experience heightened excitability and generate and transmit pain signals. Extensive studies have been carried out to elucidate how prostaglandins play their roles for such signaling at the cellular and molecular levels. Here, we briefly summarize the roles of arachidonic acid-derived prostaglandins, focusing on four prostaglandins and one thromboxane, particularly in terms of their actions on afferent nociceptors. We discuss the biosynthesis of the prostaglandins, their specific action sites, the pathological alteration of the expression levels of related proteins, the neuronal outcomes of receptor stimulation, their correlation with behavioral nociception, and the pharmacological efficacy of their regulators. This overview will help to a better understanding of the pathological roles that prostaglandins play in the somatosensory system and to a finding of critical molecular contributors to normalizing pain.
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Affiliation(s)
- Yongwoo Jang
- Department of Psychiatry and Program in Neuroscience, McLean Hospital, Harvard Medical School, Belmont, MA, 02478, USA.,Department of Biomedical Engineering, Hanyang University, Seoul, 04763, South Korea
| | - Minseok Kim
- Department of Biomedical Sciences, Korea University, Seoul, 02841, South Korea
| | - Sun Wook Hwang
- Department of Biomedical Sciences, Korea University, Seoul, 02841, South Korea. .,Department of Physiology, College of Medicine, Korea University, Seoul, 02841, South Korea.
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11
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Luzhansky ID, Sudlow LC, Brogan DM, Wood MD, Berezin MY. Imaging in the repair of peripheral nerve injury. Nanomedicine (Lond) 2019; 14:2659-2677. [PMID: 31612779 PMCID: PMC6886568 DOI: 10.2217/nnm-2019-0115] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 08/20/2019] [Indexed: 12/25/2022] Open
Abstract
Surgical intervention followed by physical therapy remains the major way to repair damaged nerves and restore function. Imaging constitutes promising, yet underutilized, approaches to improve surgical and postoperative techniques. Dedicated methods for imaging nerve regeneration will potentially provide surgical guidance, enable recovery monitoring and postrepair intervention, elucidate failure mechanisms and optimize preclinical procedures. Herein, we present an outline of promising innovations in imaging-based tracking of in vivo peripheral nerve regeneration. We emphasize optical imaging because of its cost, versatility, relatively low toxicity and sensitivity. We discuss the use of targeted probes and contrast agents (small molecules and nanoparticles) to facilitate nerve regeneration imaging and the engineering of grafts that could be used to track nerve repair. We also discuss how new imaging methods might overcome the most significant challenges in nerve injury treatment.
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Affiliation(s)
- Igor D Luzhansky
- Department of Radiology, Washington University School of Medicine, St Louis, MO 63110, USA
- The Institute of Materials Science & Engineering, Washington University, St Louis, MO 63130, USA
| | - Leland C Sudlow
- Department of Radiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - David M Brogan
- Department of Orthopedic Surgery, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Matthew D Wood
- Department of Surgery, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Mikhail Y Berezin
- Department of Radiology, Washington University School of Medicine, St Louis, MO 63110, USA
- The Institute of Materials Science & Engineering, Washington University, St Louis, MO 63130, USA
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12
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Benzothiophenes as Potent Analgesics Against Neuropathic Pain. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1112:245-254. [PMID: 30637702 DOI: 10.1007/978-981-13-3065-0_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Neuropathic pain arises because of neuronal injury. Unlike inflammatory pain which can be managed by classical nonsteroid anti-inflammatory drugs (NSAIDs), neuropathic pain is difficult to treat. The classical NSAIDs work through inhibition of cyclooxygenase 2 (COX2) enzyme. However, COX2 inhibitors are insufficient to treat neuropathic pain. Hence, it becomes important to explore for novel molecules acting through cell surface molecules like ion channels, for the treatment of neuropathic pain. We investigated multiple bromobenzothiophene carboxamides for their efficacy against neuropathic pain. Interestingly, AS6 was found to be very effective in treating neuropathic pain through inhibition of Kv4.3 ion channel. AS6 also reduced the COX2 overexpression associated with neuropathic pain. These results as well as results from our previous study indicate that AS6 can be a potent antinociceptive agent against both inflammatory and neuropathic pain.
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Li QB, Chang L, Ye F, Luo QH, Tao YX, Shu HH. Role of spinal cyclooxygenase-2 and prostaglandin E2 in fentanyl-induced hyperalgesia in rats. Br J Anaesth 2019; 120:827-835. [PMID: 29576123 DOI: 10.1016/j.bja.2017.11.103] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 11/20/2017] [Accepted: 11/29/2017] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Accumulated evidence suggests that spinal cyclooxygenase-2 (COX-2) and prostaglandin E2 (PGE2) may be implicated in the development of opioid-induced hyperalgesia. METHODS Rats received subcutaneous fentanyl injections at different doses (20-80 μg kg-1), four separate times at 15-min intervals. Some rats only received fentanyl (60 μg kg-1 × 4 doses) with or without surgical incision. Fentanyl-induced hyperalgesia was evaluated via a tail-pressure or paw-withdrawal test. The concentrations of spinal COX-2, EP-1 receptor (EP-1R) mRNA, and PGE2 were measured. The effects of the COX-2 inhibitor, parecoxib (intraperitoneal 10 mg kg-1), or the EP-1R antagonist, SC51089 (intraperitoneal 100 μg kg-1), on hyperalgesia and spinal PGE2 were examined. RESULTS Acute repeated injections of fentanyl dose-dependently induced mechanical hyperalgesia, which reached a peak at the 1st day and persisted for 1-4 days postinjection. This hyperalgesia could be partly or totally prevented by the pretreatment of either parecoxib or SC51089. Consistently, the levels of spinal COX-2 mRNA and PGE2 were also dose-dependently increased, reaching a peak at the first day and persisting for 2 days postinjection. Pretreatment with parecoxib could block the increase in spinal PGE2 and had no effects on spinal COX-2 and EP-1R mRNA. Fentanyl injection enhanced incision-induced mechanical and thermal hyperalgesia. CONCLUSIONS Acute repeated fentanyl administration dose-dependently produced mechanical hyperalgesia and augmented surgery induced postoperative hyperalgesia. This behavioural change was paralleled with an increase in spinal COX-2 mRNA and PGE2 after fentanyl administration. Inhibition of COX-2 or blockade of EP-1R can partly or totally prevent hyperalgesia.
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Affiliation(s)
- Q B Li
- Department of Anesthesiology, Guangdong Second Provincial General Hospital, Guangzhou, Guangdong, China; Department of Anesthesiology, First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China; Department of Anesthesiology, Tianjin Children's Hospital, Tianjin, China
| | - L Chang
- Department of Anesthesiology, Guangdong Second Provincial General Hospital, Guangzhou, Guangdong, China
| | - F Ye
- Department of Anesthesiology, First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Q H Luo
- Department of Anesthesiology, Guangdong Second Provincial General Hospital, Guangzhou, Guangdong, China
| | - Y X Tao
- Department of Anesthesiology, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA; Neuroscience Research Institute, Zhengzhou University Academy of Medical Science, Zhengzhou, Henan, China
| | - H H Shu
- Department of Anesthesiology, Guangdong Second Provincial General Hospital, Guangzhou, Guangdong, China.
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González-Ramos G, Cohen EV, Luce V, González MJ. Clinical social work in the care of Parkinson's disease: role, functions, and opportunities in integrated health care. SOCIAL WORK IN HEALTH CARE 2019; 58:108-125. [PMID: 31307342 DOI: 10.1080/00981389.2018.1544600] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 10/15/2018] [Accepted: 11/01/2018] [Indexed: 06/10/2023]
Abstract
Healthcare reform, including the focus on chronic illness, the growing role of neuroscience, the emphasis on collaborative interprofessional care, and more recently, on integrated medical and behavioral healthcare, have important implications for social work education and practice. Parkinson's disease, a chronic neurodegenerative illness exemplifying these trends, is an area in which social workers are increasingly involved. This paper provides (1) an overview of Parkinson's disease and its complexity, (2) a summary of role and functions identified in a survey of health social workers working with Parkinson's disease and/or neurology, and (3) education and practice recommendations for the social work profession.
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Affiliation(s)
| | - Elaine V Cohen
- a Silver School of Social Work , New York University , New York , USA
| | - Virge Luce
- a Silver School of Social Work , New York University , New York , USA
| | - Manny J González
- b School of Social Work, College for Design and Social Inquiry , Florida Atlantic University , Boca Raton , USA
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Granulocyte-macrophage colony-stimulating factor receptor expression in clinical pain disorder tissues and role in neuronal sensitization. Pain Rep 2018; 3:e676. [PMID: 30534627 PMCID: PMC6181465 DOI: 10.1097/pr9.0000000000000676] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 06/25/2018] [Accepted: 07/06/2018] [Indexed: 11/26/2022] Open
Abstract
Supplemental Digital Content is Available in the Text. Introduction: Granulocyte-macrophage colony-stimulating factor receptor (GM-CSFR) is highly expressed in peripheral macrophages and microglia, and is involved in arthritis and cancer pain in animal models. However, there is limited information on GM-CSFR expression in human central nervous system (CNS), peripheral nerves, or dorsal root ganglia (DRG), particularly in chronic pain conditions. Objectives: Immunohistochemistry was used to quantify GM-CSFR expression levels in human tissues, and functional sensory effects of GM-CSF were studied in cultured DRG neurons. Results: Granulocyte-macrophage colony-stimulating factor receptor was markedly increased in microglia at lesional sites of multiple sclerosis spinal cords (P = 0.01), which co-localised with macrophage marker CD68 (P = 0.009). In human DRG, GM-CSFR was expressed in a subset of small/medium diameter cells (30%) and few large cells (10%), with no significant change in avulsion-injured DRG. In peripheral nerves, there was a marked decrease in axonal GM-CSFR after chronic painful nerve injury (P = 0.004) and in painful neuromas (P = 0.0043); CD-68–positive macrophages were increased (P = 0.017) but did not appear to express GM-CSFR. Although control synovium showed absent GM-CSFR immunostaining, this was markedly increased in macrophages of painful osteoarthritis knee synovium. Granulocyte-macrophage colony-stimulating factor receptor was expressed in 17 ± 1.7% of small-/medium-sized cultured adult rat DRG neurons, and in 27 ± 3.3% of TRPV1-positive neurons. Granulocyte-macrophage colony-stimulating factor treatment sensitized capsaicin responses in vitro, which were diminished by p38 MAPK or TrkA inhibitors. Conclusion: Our findings support GM-CSFR as a therapeutic target for pain and hypersensitivity in clinical CNS and peripheral inflammatory conditions. Although GM-CSFR was decreased in chronic painful injured peripheral nerves, it could mediate CNS neuroinflammatory effects, which deserves study.
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Janjic JM, Vasudeva K, Saleem M, Stevens A, Liu L, Patel S, Pollock JA. Low-dose NSAIDs reduce pain via macrophage targeted nanoemulsion delivery to neuroinflammation of the sciatic nerve in rat. J Neuroimmunol 2018. [PMID: 29519721 DOI: 10.1016/j.jneuroim.2018.02.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Neuroinflammation involving macrophages elevates Prostaglandin E2, associated with neuropathic pain. Treatment with non-steroidal anti-inflammatory drugs (NSAIDs) inhibits cyclooxygenase, reducing PGE2. However, NSAIDs cause physiological complications. We developed nanoemulsions incorporating celecoxib and near infrared dye. Intravenous injected nanoemulsion is incorporated into monocytes that accumulate at the injury; revealed in live animals by fluorescence. A single dose (celecoxib 0.24 mg/kg) provides targeted delivery in chronic constriction injury rats, resulting in significant reduction in the visualized inflammation, infiltration of macrophages, COX-2 and PGE2. Animals exhibit relief from hypersensitivity persisting at least four-days. The total body burden of drug is reduced by >2000 fold over oral drug delivery.
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Affiliation(s)
- Jelena M Janjic
- Graduate School of Pharmaceutical Sciences, School of Pharmacy, Duquesne University, Pittsburgh, PA 15282, United States; Chronic Pain Research Consortium, Duquesne University, Pittsburgh, PA 15282, United States.
| | - Kiran Vasudeva
- Chronic Pain Research Consortium, Duquesne University, Pittsburgh, PA 15282, United States; Department of Biological Sciences, Bayer School of Natural & Environmental Science, Duquesne University, Pittsburgh, PA 15282, United States.
| | - Muzamil Saleem
- Chronic Pain Research Consortium, Duquesne University, Pittsburgh, PA 15282, United States; Department of Biological Sciences, Bayer School of Natural & Environmental Science, Duquesne University, Pittsburgh, PA 15282, United States.
| | - Andrea Stevens
- Chronic Pain Research Consortium, Duquesne University, Pittsburgh, PA 15282, United States; Department of Biological Sciences, Bayer School of Natural & Environmental Science, Duquesne University, Pittsburgh, PA 15282, United States.
| | - Lu Liu
- Graduate School of Pharmaceutical Sciences, School of Pharmacy, Duquesne University, Pittsburgh, PA 15282, United States; Chronic Pain Research Consortium, Duquesne University, Pittsburgh, PA 15282, United States.
| | - Sravan Patel
- Graduate School of Pharmaceutical Sciences, School of Pharmacy, Duquesne University, Pittsburgh, PA 15282, United States; Chronic Pain Research Consortium, Duquesne University, Pittsburgh, PA 15282, United States.
| | - John A Pollock
- Chronic Pain Research Consortium, Duquesne University, Pittsburgh, PA 15282, United States; Department of Biological Sciences, Bayer School of Natural & Environmental Science, Duquesne University, Pittsburgh, PA 15282, United States.
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Chu LW, Chen JY, Wu PC, Wu BN. Atorvastatin prevents neuroinflammation in chronic constriction injury rats through nuclear NFκB downregulation in the dorsal root ganglion and spinal cord. ACS Chem Neurosci 2015; 6:889-98. [PMID: 25874913 DOI: 10.1021/acschemneuro.5b00032] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Atorvastatin, traditionally used to treat hyperlipidemia, belongs to a class of 3-hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA) reductase inhibitors. This study investigated the antineuroinflammatory and antihyperalgesic effects of atorvastatin in dorsal root ganglia (DRG) and spinal cord for chronic constriction injury (CCI) neuropathic pain in rats. Fifty-four Sprague-Dawley rats were divided into three groups including sham, CCI, and CCI+atorvastatin. Rats were orally administered atorvastatin (10 mg/kg/day) once daily for 2 weeks after surgery and sacrificed at days 3, 7, and 14. All animals were assessed for mechanical allodynia and thermal hyperalgesia in both hindpaws. Western blotting, immunofluorescence, and enzyme-linked immunosorbent assay (ELISA) were used to detect inflammatory proteins and proinflammatory cytokines at day 7 after surgery. Pain behaviors were significantly reduced in the CCI+atorvastatin group compared to the CCI group. Atorvastatin attenuated CCI-induced inflammatory mediators (pAkt/Akt, COX-2, iNOS, EP1, and EP4) and reduced proinflammatory cytokines TNF-α and IL-1β levels in DRG and spinal cord. Atorvastatin also inhibited nuclear pNFκB activation. Double immunofluorescent staining further demonstrated that pNFκB proteins were decreased by atorvastatin in DRG satellite cells and spinal microglia. Atorvastatin may primarily inhibit the nuclear translocation of pNFκB to prevent CCI-induced peripheral neuropathic pain. Atorvastatin exhibits antineuroinflammatory and antinociceptive properties in the central and peripheral nerve systems.
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Affiliation(s)
| | - Jun-Yih Chen
- Division of Neurosurgery, Kaohsiung Veterans General Hospital, Kaohsiung 813, Taiwan
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Efstathiou MA, Stefanakis M, Savva C, Giakas G. Effectiveness of neural mobilization in patients with spinal radiculopathy: A critical review. J Bodyw Mov Ther 2015; 19:205-12. [DOI: 10.1016/j.jbmt.2014.08.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 08/08/2014] [Accepted: 08/10/2014] [Indexed: 02/08/2023]
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Lau YM, Wong SC, Tsang SW, Lau WK, Lu AP, Zhang H. Cellular sources of cyclooxygenase-1 and -2 up-regulation in the spinal dorsal horn after spinal nerve ligation. Neuropathol Appl Neurobiol 2015; 40:452-63. [PMID: 23899306 DOI: 10.1111/nan.12078] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Accepted: 07/29/2013] [Indexed: 12/30/2022]
Abstract
AIMS Recent studies suggested that the development of neuropathic pain associated with neural injury may be partly due to up-regulation of cyclooxygenase (COX) in the central nervous system. However, the cellular sources of COX-1 and COX-2 up-regulation following nerve injury are unclear. METHODS We investigated the spinal cellular sources of COX-1 and COX-2 in association with allodynia following L5 spinal nerve ligation (SNL). RESULTS Post-SNL pain-related behaviour was shown by increased sensitivity to mechanical stimulation. There was a significant increase in both COX-1 and COX-2 immunoreactivity (P < 0.01) on the ipsilateral side of spinal dorsal horn. Double immunofluorescence labelling demonstrated that COX-1 immunoreactive cells colocalized chiefly with dorsal horn neuronal nuclei and microglia, whereas COX-2 was expressed in neuronal cytoplasm. CONCLUSION These findings demonstrate that while spinal dorsal horn neurones are important source of COX-1 and COX-2 after nerve injury, microglia also contribute to the pathogenesis of neuropathic pain, partly by producing additional COX-1.
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Affiliation(s)
- Yee Man Lau
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong, China
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Pathak NN, Balaganur V, Lingaraju MC, More AS, Kant V, Kumar D, Kumar D, Tandan SK. Antihyperalgesic and anti-inflammatory effects of atorvastatin in chronic constriction injury-induced neuropathic pain in rats. Inflammation 2014; 36:1468-78. [PMID: 23872719 DOI: 10.1007/s10753-013-9688-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Atorvastatin is a 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase inhibitor used in treatment of hypercholesterolemia and prevention of coronary heart disease. The aim of this study is to investigate the antihyperalgesic and anti-inflammatory effects of atorvastatin (3, 10, and 30 mg/kg by oral gavages for 14 days) in chronic constriction injury (CCI) model of neuropathic pain in rats. CCI caused significant increase in tumor necrosis factor-α, interleukin 1 beta, prostaglandin E2, along with matrix metalloproteases (MMP-2) and nerve growth factor (NGF) levels in sciatic nerve and spinal cord concomitant with mechanical and thermal hyperalgesia, which were significantly reduced by oral administration of atorvastatin for 14 days as compared to CCI rats. Our study demonstrated that atorvastatin attenuates neuropathic pain through inhibition of cytokines, MMP-2, and NGF in sciatic nerve and spinal cord suggesting that atorvastatin could be an additional therapeutic strategy in management of neuropathic pain.
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Affiliation(s)
- Nitya N Pathak
- Division of Pharmacology and Toxicology, Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, 243 122, India
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Barr GA, Hunter DA. Interactions between glia, the immune system and pain processes during early development. Dev Psychobiol 2014; 56:1698-710. [PMID: 24910104 DOI: 10.1002/dev.21229] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 05/15/2014] [Indexed: 01/10/2023]
Abstract
Pain is a serious problem for infants and children and treatment options are limited. Moreover, infants born prematurely or hospitalized for illness likely have concurrent infection that activates the immune system. It is now recognized that the immune system in general and glia in particular influence neurotransmission and that the neural bases of pain are intimately connected to immune function. We know that injuries that induce pain activate immune function and suppressing the immune system alleviates pain. Despite this advance in our understanding, virtually nothing is known of the role that the immune system plays in pain processing in infants and children, even though pain is a serious clinical issue in pediatric medicine. This brief review summarizes the existing data on immune-neural interactions in infants, providing evidence for the immaturity of these interactions.
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Affiliation(s)
- Gordon A Barr
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, 19104.
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Murai N, Tsukamoto M, Tamura S, Aoki T, Matsuoka N. Antinociceptive effects of AS1069562, the (+)-isomer of indeloxazine, on spinal hypersensitivity induced by intrathecal injection of prostaglandin in mice: Comparison with duloxetine and amitriptyline. Eur J Pharmacol 2014; 733:54-61. [DOI: 10.1016/j.ejphar.2014.03.038] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 02/25/2014] [Accepted: 03/16/2014] [Indexed: 10/25/2022]
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Avila-Martin G, Galan-Arriero I, Ferrer-Donato A, Busquets X, Gomez-Soriano J, Escribá PV, Taylor J. Oral 2-hydroxyoleic acid inhibits reflex hypersensitivity and open-field-induced anxiety after spared nerve injury. Eur J Pain 2014; 19:111-22. [PMID: 24824524 DOI: 10.1002/ejp.528] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/06/2014] [Indexed: 12/19/2022]
Abstract
BACKGROUND Recently, fatty acids have been shown to modulate sensory function in animal models of neuropathic pain. In this study, the antinociceptive effect of 2-hydroxyoleic acid (2-OHOA) was assessed following spared nerve injury (SNI) with reflex and cerebrally mediated behavioural responses. METHODS Initial antinociceptive behavioural screening of daily administration of 2-OHOA (400 mg/kg, p.o.) was assessed in Wistar rats by measuring hindlimb reflex hypersensitivity to von Frey and thermal plate stimulation up to 7 days after SNI, while its modulatory effect on lumbar spinal dorsal horn microglia reactivity was assessed with OX-42 immunohistochemistry. In vitro the effect of 2-OHOA (120 μM) on cyclooxygenase protein expression (COX-2/COX-1 ratio) in lipopolysaccharide-activated macrophage cells was tested with Western blot analysis. Finally, the effects of 2-OHOA treatment on the place escape aversion paradigm (PEAP) and the open-field-induced anxiety test were tested at 21 days following nerve injury compared with vehicle-treated sham and pregabalin-SNI (30 mg/kg, p.o.) control groups. RESULTS Oral 2-OHOA significantly reduced ipsilateral mechanical and thermal hypersensitivity up to 7 days after SNI. Additionally 2-OHOA decreased the COX-2/COX-1 ratio in lipopolysaccharide-activated macrophage cells and OX-42 expression within the ipsilateral lumbar spinal dorsal horn 7 days after SNI. 2-OHOA significantly restored inner-zone exploration in the open-field test compared with the vehicle-treated sham group at 21 days after SNI. CONCLUSIONS Oral administration of the modified omega 9 fatty acid, 2-OHOA, mediates antinociception and prevents open-field-induced anxiety in the SNI model in Wistar rats, which is mediated by an inhibition of spinal dorsal horn microglia activation.
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Affiliation(s)
- G Avila-Martin
- Sensorimotor Function Group, SESCAM, Hospital Nacional de Parapléjicos, Toledo, Spain
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Zhu X, Li Q, Chang R, Yang D, Song Z, Guo Q, Huang C. Curcumin alleviates neuropathic pain by inhibiting p300/CBP histone acetyltransferase activity-regulated expression of BDNF and cox-2 in a rat model. PLoS One 2014; 9:e91303. [PMID: 24603592 PMCID: PMC3946321 DOI: 10.1371/journal.pone.0091303] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 02/10/2014] [Indexed: 12/31/2022] Open
Abstract
The management of neuropathic pain is still a major challenge because of its unresponsiveness to most common treatments. Curcumin has been reported to play an active role in the treatment of various neurological disorders, such as neuropathic pain. Curcumin has long been recognized as a p300/CREB-binding protein (CBP) inhibitor of histone acetyltransferase (HAT) activity. However, this mechanism has never been investigated for the treatment of neuropathic pain with curcumin. The aim of the present study was to investigate the anti-nociceptive role of curcumin in the chronic constriction injury (CCI) rat model of neuropathic pain. Furthermore, with this model we investigated the effect of curcumin on P300/CBP HAT activity-regulated release of the pro-nociceptive molecules, brain-derived neurotrophic factor (BDNF) and cyclooxygenase-2 (Cox-2). Treatment with 40 and 60 mg/kg body weight curcumin for 7 consecutive days significantly attenuated CCI-induced thermal hyperalgesia and mechanical allodynia, whereas 20 mg/kg curcumin showed no significant analgesic effect. Chromatin immunoprecipitation analysis revealed that curcumin dose-dependently reduced the recruitment of p300/CBP and acetyl-Histone H3/acetyl-Histone H4 to the promoter of BDNF and Cox-2 genes. A similar dose-dependent decrease of BDNF and Cox-2 in the spinal cord was also observed after curcumin treatment. These results indicated that curcumin exerted a therapeutic role in neuropathic pain by down-regulating p300/CBP HAT activity-mediated gene expression of BDNF and Cox-2.
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Affiliation(s)
- Xiaoyan Zhu
- Department of Anesthesiology, Xiangya Hospital of Central South University, Changsha, China
| | - Qian Li
- Department of Anesthesiology, Xiangya Hospital of Central South University, Changsha, China
| | - Ruimin Chang
- Liver Cancer Laboratory, Xiangya Hospital of Central South University, Changsha, China
| | - Dong Yang
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zongbing Song
- Department of Anesthesiology, Xiangya Hospital of Central South University, Changsha, China
| | - Qulian Guo
- Department of Anesthesiology, Xiangya Hospital of Central South University, Changsha, China
| | - Changsheng Huang
- Department of Anesthesiology, Xiangya Hospital of Central South University, Changsha, China
- * E-mail:
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Bodkin JV, Fernandes ES. TRPV1 and SP: key elements for sepsis outcome? Br J Pharmacol 2013; 170:1279-92. [PMID: 23145480 PMCID: PMC3838676 DOI: 10.1111/bph.12056] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Revised: 10/10/2012] [Accepted: 11/04/2012] [Indexed: 12/30/2022] Open
Abstract
UNLABELLED Sensory neurons play important roles in many disorders, including inflammatory diseases, such as sepsis. Sepsis is a potentially lethal systemic inflammatory reaction to a local bacterial infection, affecting thousands of patients annually. Although associated with a high mortality rate, sepsis outcome depends on the severity of systemic inflammation, which can be directly influenced by several factors, including the immune response of the patient. Currently, there is a lack of effective drugs to treat sepsis, and thus there is a need to develop new drugs to improve sepsis outcome. Several mediators involved in the formation of sepsis have now been identified, but the mechanisms underlying the pathology remain poorly understood. The transient receptor potential vanilloid 1 (TRPV1) receptor and the neuropeptide substance P (SP) have recently been demonstrated as important targets for sepsis and are located on sensory neurones and non-neuronal cells. Herein, we highlight and review the importance of sensory neurones for the modulation of sepsis, with specific focus on recent findings relating to TRPV1 and SP, with their distinct abilities to alter the transition from local to systemic inflammation and also modify the overall sepsis outcome. We also emphasize the protective role of TRPV1 in this context. LINKED ARTICLES This article is part of a themed section on Neuropeptides. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2013.170.issue-7.
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Petho G, Reeh PW. Sensory and signaling mechanisms of bradykinin, eicosanoids, platelet-activating factor, and nitric oxide in peripheral nociceptors. Physiol Rev 2013; 92:1699-775. [PMID: 23073630 DOI: 10.1152/physrev.00048.2010] [Citation(s) in RCA: 191] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Peripheral mediators can contribute to the development and maintenance of inflammatory and neuropathic pain and its concomitants (hyperalgesia and allodynia) via two mechanisms. Activation or excitation by these substances of nociceptive nerve endings or fibers implicates generation of action potentials which then travel to the central nervous system and may induce pain sensation. Sensitization of nociceptors refers to their increased responsiveness to either thermal, mechanical, or chemical stimuli that may be translated to corresponding hyperalgesias. This review aims to give an account of the excitatory and sensitizing actions of inflammatory mediators including bradykinin, prostaglandins, thromboxanes, leukotrienes, platelet-activating factor, and nitric oxide on nociceptive primary afferent neurons. Manifestations, receptor molecules, and intracellular signaling mechanisms of the effects of these mediators are discussed in detail. With regard to signaling, most data reported have been obtained from transfected nonneuronal cells and somata of cultured sensory neurons as these structures are more accessible to direct study of sensory and signal transduction. The peripheral processes of sensory neurons, where painful stimuli actually affect the nociceptors in vivo, show marked differences with respect to biophysics, ultrastructure, and equipment with receptors and ion channels compared with cellular models. Therefore, an effort was made to highlight signaling mechanisms for which supporting data from molecular, cellular, and behavioral models are consistent with findings that reflect properties of peripheral nociceptive nerve endings. Identified molecular elements of these signaling pathways may serve as validated targets for development of novel types of analgesic drugs.
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Affiliation(s)
- Gábor Petho
- Pharmacodynamics Unit, Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Pécs, Pécs, Hungary
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Role of inflammation and cytokines in peripheral nerve regeneration. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2013; 108:173-206. [PMID: 24083435 DOI: 10.1016/b978-0-12-410499-0.00007-1] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This chapter provides a review of immune reactions involved in classic as well as alternative methods of peripheral nerve regeneration, and mainly with a view to understanding their beneficial effects. Axonal degeneration distal to nerve damage triggers a cascade of inflammatory events alongside injured nerve fibers known as Wallerian degeneration (WD). The early inflammatory reactions of WD comprise the complement system, arachidonic acid metabolites, and inflammatory mediators that are related to myelin fragmentation and activation of Schwann cells. Fine-tuned upregulation of the cytokine/chemokine network by Schwann cells activates resident and hematogenous macrophages to complete the clearance of axonal and myelin debris and stimulate regrowth of axonal sprouts. In addition to local effects, immune reactions of neuronal bodies and glial cells are also implicated in the survival and conditioning of neurons to regenerate severed nerves. Understanding of the cellular and molecular interactions between the immune system and peripheral nerve injury opens new possibilities for targeting inflammatory mediators to improve functional reinnervation.
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Ruan D, So SP. Screening and identification of dietary oils and unsaturated fatty acids in inhibiting inflammatory prostaglandin E2 signaling in fat stromal cells. Altern Ther Health Med 2012; 12:143. [PMID: 22938033 PMCID: PMC3532401 DOI: 10.1186/1472-6882-12-143] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 08/23/2012] [Indexed: 12/18/2022]
Abstract
Background The molecular mechanisms of dietary oils (such as fish oil) and unsaturated fatty acids, which are widely used by the public for anti-inflammation and vascular protection, have not been settled yet. In this study, prostaglandin E2 (PGE2)-mediated calcium signaling was used to screen dietary oils and eight unsaturated fatty acids for identification of their anti-inflammatory mechanisms. Isolated fat/stromal cells expressing endogenous PGE2 receptors and an HEK293 cell line specifically expressing the recombinant human PGE2 receptor subtype-1 (EP1) were cultured and used in live cell calcium signaling assays. The different dietary oils and unsaturated fatty acids were used to affect cell signaling under the specific stimulation of a pathological amount of inflammatory PGE2. Results It was identified that fish oil best inhibited the PGE2 signaling in the primary cultured stromal cells. Second, docosahexaenoic acid (DHA), found in abundance in fish oil, was identified as a key factor of inhibition of PGE2 signaling. Eicosapentaenoic acid (EPA), another major fatty acid found in fish oil and tested in this study was found to have small effect on EP1 signaling. The study suggested one of the four PGE2 subtype receptors, EP1 as the key target for the fish oil and DHA target. These findings were further confirmed by using the recombinant EP1 expressed in HEK293 cells as a target. Conclusion This study demonstrated the new mechanism behind the positive effects of dietary fish oils in inhibiting inflammation originates from the rich concentration of DHA, which can directly inhibit the inflammatory EP1-mediated PGE2 receptor signaling, and that the inflammatory response stimulated by PGE2 in the fat stromal cells, which directly related to metabolic diseases, could be down regulated by fish oil and DHA. These findings also provided direct evidence to support the use of dietary oils and unsaturated fatty acids for protection against heart disease, pain, and cancer resulted from inflammatory PGE2.
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Hong B, Krusche CA, Schwabe K, Friedrich S, Klein R, Krauss JK, Nakamura M. Cyclooxygenase-2 supports tumor proliferation in vestibular schwannomas. Neurosurgery 2012; 68:1112-7. [PMID: 21221032 DOI: 10.1227/neu.0b013e318208f5c7] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Recent studies have shown that cyclooxygenase-2 (COX-2) plays an important role in tumor growth and neovascularization. However, COX-2 expression in vestibular schwannomas (VSs) has not been investigated. OBJECTIVE To analyze the pattern of COX-2 expression in sporadic and neurofibromatosis type 2 (NF2)-associated VSs and its relationship with tumor proliferation and microvessel density. METHODS Fifteen sporadic and 15 NF2-associated VSs were examined for COX-2 expression, microvessel density, and proliferation rate by immunohistochemical methods. Immunohistochemical scores were used to interpret the extent and intensity of COX-2 staining. Microvessel density (MVD) was determined using von Willebrand factor (vWf). Proliferation rate was quantified using Ki-67. The relationship among COX-2 expression, MVD, and proliferation rate was statistically analyzed. RESULTS COX-2 expression was detected in 29 (96.67%) of 30 VSs, with no significant difference between sporadic and NF2-associated VSs (P = .722). In 6 (20%) VSs, COX-2 expression was graded as strong, in 12 (40%) as moderate, and in 11 (36.7%) as weak. VSs with high proliferation showed significantly higher COX-2 expression (P = .015) than VSs with low proliferation. COX-2 expression and MVD did not show specific biological correlations (P = .035). CONCLUSION Our data demonstrate that COX-2 is expressed in VSs. High COX-2 expression in VSs with high proliferation rates suggests that the COX-2 pathway may be involved in the development and growth of VSs.
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Affiliation(s)
- Bujung Hong
- Department of Neurosurgery, Hannover Medical School, Hannover, Germany.
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Ma W, St-Jacques B, Cruz Duarte P. Targeting pain mediators induced by injured nerve-derived COX2 and PGE2 to treat neuropathic pain. Expert Opin Ther Targets 2012; 16:527-40. [DOI: 10.1517/14728222.2012.680955] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Liou JT, Yuan HB, Mao CC, Lai YS, Day YJ. Absence of C-C motif chemokine ligand 5 in mice leads to decreased local macrophage recruitment and behavioral hypersensitivity in a murine neuropathic pain model. Pain 2012; 153:1283-1291. [PMID: 22494919 DOI: 10.1016/j.pain.2012.03.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 02/23/2012] [Accepted: 03/07/2012] [Indexed: 10/28/2022]
Abstract
Accumulated evidence suggests that the C-C motif chemokine ligand 5 (CCL5) modulates migration of inflammatory cells in several pathological conditions. This study tested the hypothesis that lack of CCL5 would modulate the recruitment of inflammatory cells to painful, inflamed sites and could attenuate pain in a murine chronic neuropathic pain model. Nociceptive sensitization, immune cell infiltration, multiple cytokine expression, and opioid peptide expression in damaged nerves were studied in wild-type (CCL5 +/+) and CCL5-deficient (CCL5 -/-) mice after partial sciatic nerve ligation (PSNL). Results indicated that CCL5 -/- mice had less behavioral hypersensitivity after PSNL. Macrophage infiltration and proinflammatory cytokines (tumor necrosis factor-α, interleukin [IL]-1β, IL-6, and interferon-γ) in damaged nerves following PSNL were significantly decreased in CCL5 -/- mice. Conversely, several antiinflammatory cytokine (IL-4 and IL-10) proteins were significantly increased in CCL5 -/- animals and the expression of enkephalin, β-endorphin, and dynorphin mRNA was significantly lower than in wild-type control mice. These results represent the first evidence that CCL5 is capable of regulating the pathway that controls hyperalgesia at the level of the peripheral injured site in a murine chronic neuropathic pain model. We demonstrated that lack of CCL5 modulated cell infiltration and the proinflammatory milieu within the injured nerve. Attenuated behavioral hypersensitivity in CCL5 -/- mice observed in the current study could be a result of decreased macrophage infiltration, mobilization, and functional ability at injured sites. Collectively, the present study results suggest that CCL5 receptor antagonists may ultimately provide a novel class of analgesics for therapeutic intervention in chronic neuropathic pain.
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Affiliation(s)
- Jiin-Tarng Liou
- Department of Anesthesiology, Chang Gung Memorial Hospital, Linkou, Taiwan, ROC Transgenic & Molecular Immunogenetics Laboratory, Chang Gung Memorial Hospital, Linkou, Taiwan, ROC Graduate Institutes of Clinical Medical Sciences, Chang Gung University, Linkou, Taiwan, ROC Department of Anesthesiology, Taipei-Veterans General Hospital and School of Medicine, National Yang-Ming University, Taipei, Taiwan, ROC Department of Medicine, Chang Gung University, Linkou, Taiwan, ROC
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Abstract
Prostaglandin E(2) (PGE(2)), a cyclooxygenase (COX) product, is the best known lipid mediator that contributes to inflammatory pain. Nonsteroidal anti-inflammatory drugs (NSAIDs), inhibitors of COX-1 and/or COX-2, suppress inflammatory pain by reducing generation of prostanoids, mainly PGE(2), while they exhibit gastrointestinal, renal and cardiovascular toxicities. Selective inhibitors of microsomal PGE synthase-1 and subtype-selective antagonists of PGE(2) receptors, particularly EP(1) and EP(4), may be useful as analgesics with minimized side-effects. Protein kinase C (PKC) and PKA downstream of EP(1) and EP(4), respectively, sensitize/activate multiple molecules including transient receptor potential vanilloid-1 (TRPV1) channels, purinergic P2X3 receptors, and voltage-gated calcium or sodium channels in nociceptors, leading to hyperalgesia. PGE(2) is also implicated in neuropathic and visceral pain and in migraine. Thus, PGE(2) has a great impact on pain signals, and pharmacological intervention in upstream and downstream signals of PGE(2) may serve as novel therapeutic strategies for the treatment of intractable pain.
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Affiliation(s)
- Atsufumi Kawabata
- Division of Pharmacology and Pathophysiology, School of Pharmacy, Kinki University, Higashi-Osaka 577–8502, Japan.
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Cruz Duarte P, St-Jacques B, Ma W. Prostaglandin E2 contributes to the synthesis of brain-derived neurotrophic factor in primary sensory neuron in ganglion explant cultures and in a neuropathic pain model. Exp Neurol 2012; 234:466-81. [PMID: 22309829 DOI: 10.1016/j.expneurol.2012.01.021] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2011] [Revised: 01/13/2012] [Accepted: 01/19/2012] [Indexed: 01/31/2023]
Abstract
Brain-derived neurotrophic factor (BDNF) exists in small to medium size neurons in adult rat dorsal root ganglion (DRG) and serves as a modulator at the first synapse of the pain transmission pathway in the spinal dorsal horn. Peripheral nerve injury increases BDNF expression in DRG neurons, an event involved in the genesis of neuropathic pain. In the present study, we tested the hypothesis that prostaglandin E2 (PGE2) over-produced in injured nerves contributes to the up-regulation of BDNF in DRG neurons. Two weeks after partial sciatic nerve ligation (PSNL), BDNF levels in the ipsilateral L4-L6 DRG of injured rats were significantly increased compared to the contralateral side. Perineural injection of a selective cyclooxygenase (COX2) inhibitor or a PGE2 EP4 receptor antagonist not only dose-dependently relieved PSNL elicited mechanical hypersensitivity, but also suppressed the increased BDNF levels in DRG neurons. PSNL shifted BDNF expression in the ipsilateral DRG from small to medium and larger size injured neurons. BDNF is mainly co-expressed with the EP1 and EP4 while moderately with the EP2 and EP3 receptor subtypes in naïve and PSNL rats. PSNL also shifted the expression of EP1-4 receptors to a larger size population of DRG neurons. In DRG explant cultures, a stabilized PGE2 analog 16,16 dimethyl PGE2 (dmPGE2) or the agonists of EP1 and EP4 receptors significantly increased BDNF levels and the phosphorylated protein kinase A (PKA), extracellular signal-regulated kinase (ERK)/mitogen activated protein kinase (MAPK) and cAMP response element binding protein (CREB). The EP1 and EP4 antagonists, a sequester of nerve growth factor (NGF), the inhibitors of PKA and MEK as well as CREB small interfering RNA suppressed dmPGE2-induced BDNF. Taken together, EP1 and EP4 receptor subtypes, PKA, ERK/MAPK and CREB signaling pathways as well as NGF are involved in PGE2-induced BDNF synthesis in DRG neurons. Injured nerve derived-PGE2 contributes to BDNF up-regulation in DRG neurons following nerve injury. Facilitating the synthesis of BDNF in primary sensory neurons is a novel mechanism underlying the role of PGE2 in the genesis of neuropathic pain.
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Liu PY, Lu CL, Wang CC, Lee IH, Hsieh JC, Chen CC, Lee HF, Lin HC, Chang FY, Lee SD. Spinal microglia initiate and maintain hyperalgesia in a rat model of chronic pancreatitis. Gastroenterology 2012; 142:165-173.e2. [PMID: 21963786 DOI: 10.1053/j.gastro.2011.09.041] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 07/21/2011] [Accepted: 09/20/2011] [Indexed: 12/15/2022]
Abstract
BACKGROUND & AIMS The chronic, persistent pain associated with chronic pancreatitis (CP) has many characteristics of neuropathic pain, initiated and maintained by the activation of spinal microglia. We investigated whether activated microglia in the thoracic spinal cord contribute to chronic pain in a rat model of CP. METHODS CP was induced in Sprague-Dawley rats by an intraductal injection of 2% trinitrobenzene sulfonic acid. Hyperalgesia was assessed by the measurement of mechanical sensitivity of the abdomen and nocifensive behavior to electrical stimulation of the pancreas. Three weeks after induction of CP, spinal samples were analyzed by immunostaining and immunoblot analyses for levels of CD11 (a marker of microglia, determined with the antibody OX42) and phosphorylated p38 (P-p38, a marker of activation of p38 mitogen-activated protein kinase signaling). We examined the effects of minocycline (inhibitor of microglia) and fractalkine (microglia-activating factor) on visceral hyperalgesia in rats with CP. RESULTS Rats with CP had increased sensitivity and nociceptive behaviors to mechanical probing of the abdomen and electrical stimulation of the pancreas. The dorsal horn of the thoracic spinal cords of rats with CP contained activated microglia (based on increased staining with OX42), with an ameboid appearance. Levels of P-p38 increased in rats with CP and colocalized with OX42-positive cells. Intrathecal injection of minocycline reversed and prevented the increase of nocifensive behaviors and levels of P-p38 in rats with CP. Fractalkine induced hyperalgesia in rats without CP, which was blocked by minocycline. CONCLUSIONS Activated spinal microglia have important roles in maintaining and initiating chronic pain in a rat model of CP. Microglia might be a target for treatment of hyperalgesia caused by pancreatic inflammation.
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Affiliation(s)
- Pei-Yi Liu
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan
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Stemkowski PL, Smith PA. Long-term IL-1β exposure causes subpopulation-dependent alterations in rat dorsal root ganglion neuron excitability. J Neurophysiol 2011; 107:1586-97. [PMID: 22170966 DOI: 10.1152/jn.00587.2011] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The effect of interleukin-1β (IL-1β) on the electrical properties of sensory neurons was assessed at levels and exposure times comparable to those found in animal models of neuropathic pain. Experiments involved whole cell current-clamp recordings from rat dorsal root ganglion (DRG) neurons in defined-medium, neuron-enriched cultures. Five- to six-day exposure to 100 pM IL-1β produced subpopulation-dependent effects on DRG neurons. These included an increase in the excitability of medium-diameter and small-diameter isolectin B(4) (IB(4))-positive neurons that was comparable to that found after peripheral nerve injury. By contrast, a reduction in excitability was observed in large-diameter neurons, while no effect was found in small-diameter IB(4)-negative neurons. Further characterization of changes in medium and small IB(4)-positive neurons revealed that some, but not all, effects of IL-1β were mediated through its receptor, IL-1RI. Although the acute actions of IL-1β on sensory neurons have been well studied and related to acute and/or inflammatory pain, the present study shows how sensory neurons respond to long-term cytokine exposure. Such effects are relevant to understanding processes that contribute to the onset of neuropathic pain.
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St-Jacques B, Ma W. Role of prostaglandin E2 in the synthesis of the pro-inflammatory cytokine interleukin-6 in primary sensory neurons: an in vivo and in vitro study. J Neurochem 2011; 118:841-54. [PMID: 21371033 DOI: 10.1111/j.1471-4159.2011.07230.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Following various types of nerve injury, cyclooxygenase 2 and prostaglandin E2 (PGE2) are universally and chronically up-regulated in injured nerves and contribute to the genesis of neuropathic pain. Persistent high levels of PGE2 likely exert chronic effects on nociceptive dorsal root ganglion (DRG) neurons. In the present study, we tested the hypothesis that injured nerve-derived PGE2 contributes to the up-regulation of the pro-inflammatory cytokine interleukin-6 (IL-6) in DRG neurons following partial sciatic nerve ligation. In naive adult rats, IL-6 was expressed in only a few small size DRG neurons which all co-expressed EP4 receptors. Partial sciatic nerve ligation increased and shifted IL-6 expression from small to medium and large size damaged DRG neurons. Perineural injection of a selective cyclooxygenase 2 inhibitor or a selective EP4 receptor antagonist significantly suppressed the up-regulation of IL-6 in DRG, suggesting that injured nerve derived PGE2 contributes to the de novo synthesis of IL-6 in DRG neurons through EP4 receptors. In cultured sensory ganglion explants, a stabilized PGE2 analog increased IL-6 mRNA and protein levels through the activation of EP4, protein kinase A, protein kinase C, extracellular regulated protein kinase/MAPK, cAMP response element binding protein and NFκB signalling pathways. Taken together, these data indicate that facilitating the de novo synthesis of pain-related cytokines in injured medium and large size DRG neurons is a novel mechanism underlying the role of injured nerve derived PGE2 in the genesis of neuropathic pain.
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Affiliation(s)
- Bruno St-Jacques
- Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada
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Anand P, Shenoy R, Palmer JE, Baines AJ, Lai RYK, Robertson J, Bird N, Ostenfeld T, Chizh BA. Clinical trial of the p38 MAP kinase inhibitor dilmapimod in neuropathic pain following nerve injury. Eur J Pain 2011; 15:1040-8. [PMID: 21576029 DOI: 10.1016/j.ejpain.2011.04.005] [Citation(s) in RCA: 124] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Revised: 03/28/2011] [Accepted: 04/05/2011] [Indexed: 12/21/2022]
Abstract
Current treatments of neuropathic pain arising from conditions such as nerve injury/compression are only partially effective, and limited in their use by side-effects. p38 mitogen-activated protein kinase (MAPK) is involved in the regulation and synthesis of inflammatory mediators, and is the target for a novel class of cytokine-suppressive anti-inflammatory drugs. p38 inhibitors may reduce neuronal sensitisation in preclinical models of neuropathic pain, particularly where there is a substantial inflammatory component. An exploratory, multicentre, double-blind, placebo-controlled, two-period, cross-over trial was undertaken to evaluate the effect of dilmapimod (SB-681323), a selective p38 MAPK inhibitor, on neuropathic pain symptoms and signs. Fifty patients with nerve trauma, radiculopathy or carpal tunnel syndrome were randomised; 43 patients completed the study. Eligible patients received oral dilmapimod and placebo twice daily for 2 weeks, with an intervening washout period of 2-4 weeks. Subjects attended weekly for efficacy and safety assessments, which included evaluation of daily and current pain intensity using an 11-point numerical rating scale (NRS), quantitative sensory testing, allodynia and global impression of change. There was a statistically significant reduction in the primary endpoint of average daily pain score during the second week of treatment among patients treated with dilmapimod (15 mg/day) compared to placebo using NRS [0.80; 95% CI (0.28, 1.33); p=0.0034]. A similar trend for effect was seen in some secondary endpoints. Dilmapimod was well tolerated, with no clinically relevant safety findings. p38 MAPK inhibitors merit further evaluation for neuropathic pain in larger clinical trials, particularly for clinically meaningful analgesic effect size.
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Affiliation(s)
- Praveen Anand
- Peripheral Neuropathy Unit, Hammersmith Hospital, Imperial College, London, UK.
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Hunter DA, Barr GA, Shivers KY, Amador N, Jenab S, Inturrisi C, Quinones-Jenab V. Interactions of estradiol and NSAIDS on carrageenan-induced hyperalgesia. Brain Res 2011; 1382:181-8. [PMID: 21281615 DOI: 10.1016/j.brainres.2011.01.075] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Revised: 01/20/2011] [Accepted: 01/22/2011] [Indexed: 11/28/2022]
Abstract
How exogenous estrogen affects inflammatory responses is poorly understood despite the large numbers of women receiving estrogen-alone hormone therapy. The aim of this study was to determine if estradiol alters injury- or inflammation-induced nociceptive responses after carrageenan administration in females and whether its effects are mediated through cyclo-oxygenase (COX) and prostaglandins (PG). To this end, paw withdrawal latencies and serum levels of PGE2 and PGD2 were measured in rats treated with estradiol (0, 10, 20, and 30%) and/or SC560 (COX-1 inhibitor) or NS398 (COX-2 inhibitor) after intraplantar carrageenan administration. Estradiol significantly increased withdrawal latencies before (baseline condition) and after carrageenan administration to one hindpaw. NS398 was anti-nociceptive only in carrageenan treated animals. SC560 increased withdrawal latencies in both paws at 1 and 5hours after carrageenan administration. Co-administration of estradiol and NS398, but not SC560, was additive except for a prolonged anti-nociceptive effects of estradiol combined with NS398. The anti-nociceptive effect extended beyond that observed with either drug or estradiol alone at the 5-hour time point. Estradiol had no significant effect on PGE2 serum levels, but both COX antagonists decreased them. Although neither estradiol nor the COX inhibitors alone had an effect on PGD2 serum levels, co-administration of NS398 and estradiol significantly elevated PGD2 levels. Taken together, our results suggest that estradiol is anti-nociceptive in the thermal test and reduces carrageenan-induced hyperalgesia. These effects are minimally altered through PG-mediated mechanisms.
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Affiliation(s)
- Deirtra A Hunter
- Hunter College and The Graduate Center, The City University of New York, NY, 10065, USA; New York State Psychiatric Institute, New York, NY, 10032, USA
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Lau W, Lau Y, Zhang H, Wong S, Bian Z. Electroacupuncture versus celecoxib for neuropathic pain in rat SNL model. Neuroscience 2010; 170:655-61. [DOI: 10.1016/j.neuroscience.2010.07.031] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Revised: 07/14/2010] [Accepted: 07/15/2010] [Indexed: 01/22/2023]
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Ma W. Chronic prostaglandin E2 treatment induces the synthesis of the pain-related peptide substance P and calcitonin gene-related peptide in cultured sensory ganglion explants. J Neurochem 2010; 115:363-72. [PMID: 20666934 DOI: 10.1111/j.1471-4159.2010.06927.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Prostaglandin E2 (PGE2) is a well known pain and pro-inflammatory mediator abundantly produced in inflamed tissue. It causes pain by directly exciting nociceptive primary sensory neurons (nociceptors) and indirectly stimulating the release of pain-related peptide substance P (SP) and calcitonin gene-related peptide (CGRP). In an ex vivo culture of sensory ganglion explants, we tested the hypothesis that PGE2 could induce the synthesis of SP and CGRP in nociceptors. A stabilized PGE2 analog, 16,16-dimethyl PGE2, in a concentration- and time-dependent manner, significantly increased mRNA and peptide levels of SP and CGRP. The agonists of EP1 and EP4 receptors also significantly increased SP and CGRP levels. Moreover, 16,16-dimethyl PGE2-induced SP and CGRP were blocked by EP1 and EP4 antagonists as well as the inhibitors of both protein kinase A and protein kinase C. Nerve growth factor was partially involved in PGE2-induced SP and CGRP synthesis. Taken together, these results indicate that PGE2 contributes to the synthesis of SP and CGRP in nociceptors, an event mediated by EP1 and EP4 receptors, nerve growth factor and protein kinase A and protein kinase C signalling pathways. We thus conclude that facilitating the synthesis of pain-related peptides in nociceptors is a novel mechanism underlying the role of PGE2 in nociception and chronic pain states.
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Affiliation(s)
- Weiya Ma
- Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada.
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Cyclooxygenase inhibitors suppress the expression of P2X3 receptors in the DRG and attenuate hyperalgesia following chronic constriction injury in rats. Neurosci Lett 2010; 478:77-81. [DOI: 10.1016/j.neulet.2010.04.069] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2010] [Revised: 04/26/2010] [Accepted: 04/27/2010] [Indexed: 01/27/2023]
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Immunological priming potentiates non-viral anti-inflammatory gene therapy treatment of neuropathic pain. Gene Ther 2009; 16:1210-22. [PMID: 19571887 PMCID: PMC2762489 DOI: 10.1038/gt.2009.79] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
We recently described a non-viral gene therapy paradigm offering long-term resolution of established neuropathic pain in several animal models. Here, the requirements for long term therapeutic effects are described, and evidence is provided for a mechanism of action based on immunological priming of the intrathecal space. Long-term pain reversal was achieved when two intrathecal injections of various naked plasmid DNA doses were separated by 5 hr to 3 days. We demonstrate that an initial DNA injection, regardless of whether a transgene is included, leads to an accumulation of phagocytic innate immune cells. This accumulation coincides with the time in which subsequent DNA injection efficacy is potentiated. We demonstrate the ability of non-coding DNA to induce short term pain reversal that is dependent on endogenous interleukin-10 (IL-10) signaling. Long term efficacy requires the inclusion of an IL-10F129S transgene in the second injection. Blockade of IL-10, via neutralizing antibody, either between the two injections or following the second injection induces therapeutic failure. These results demonstrate that this gene therapy paradigm utilizes an initial “priming” injection of DNA to induce accumulation of phagocytic immune cells, allowing for potentiated efficacy of a subsequent “therapeutic” DNA injection in a time and dose dependent manner.
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Shackelford S, Rauck R, Quessy S, Blum D, Hodge R, Philipson R. A Randomized, Double-Blind, Placebo-Controlled Trial of a Selective COX-2 Inhibitor, GW406381, in Patients With Postherpetic Neuralgia. THE JOURNAL OF PAIN 2009; 10:654-60. [DOI: 10.1016/j.jpain.2009.01.328] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Revised: 01/16/2009] [Accepted: 01/31/2009] [Indexed: 11/26/2022]
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Oshinsky ML. Insights from experimental studies into allodynia and its treatment. Curr Pain Headache Rep 2008; 10:225-30. [PMID: 18778578 DOI: 10.1007/s11916-006-0050-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Migraine is a common disorder that often is accompanied by cutaneous allodynia. Cutaneous allodynia on the head has been linked to sensitization of neurons in the trigeminal nucleus caudalis in animal models of migraine. In addition, migraine with allodynia is refractory to acute treatment with triptans. Understanding the mechanisms of allodynia, preventing its development, and finding effective treatments have become a priority in headache research. This paper reviews recent research on the pathogenesis of headache and the generation of allodynia. We discuss the regions of the nervous system that are involved in generating and maintaining headache pain and allodynia. We also discuss recent advances in the treatment of migraine based on translation research.
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Affiliation(s)
- Michael L Oshinsky
- Department of Neurology, Thomas Jefferson University, 1020 Locust Street, Suite 398 JAH, Philadelphia, PA 19107, USA.
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Ma W, Chabot JG, Vercauteren F, Quirion R. Injured nerve-derived COX2/PGE2 contributes to the maintenance of neuropathic pain in aged rats. Neurobiol Aging 2008; 31:1227-37. [PMID: 18786748 DOI: 10.1016/j.neurobiolaging.2008.08.002] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Revised: 07/15/2008] [Accepted: 08/01/2008] [Indexed: 01/01/2023]
Abstract
Neuropathic pain (NeP) is a debilitating disease afflicting mostly the aged population. Inflammatory responses in injured nerves play a pivotal role in the pathogenesis of NeP. Injured nerve derived cyclooxygenase 2/prostaglandin E2 (COX2/PGE2) contributes to the genesis of NeP at the early stage in young rats. Here we show that COX2/PGE2 is involved in the maintenance of NeP at a chronic stage in aged rats. Eighteen months after partial sciatic nerve ligation (PSNL), NeP remained prominent in aged rats. COX2 expressing macrophages and PGE2 levels were increased in injured nerves. PGE2 receptors (EP1 and EP4) and pain-related ion channel transient receptor potential vanilloid-1 (TRPV1) were increased in the ipsilateral dorsal root ganglion (DRG) neurons of aged PSNL rats. Perineural injection of a selective COX2 inhibitor NS-398 relieved NeP, reversed PSNL increased expression of EP1, EP4 and TRPV1 and suppressed the levels of pain-related peptide substance P and calcitonin gene-related peptide in DRG neurons. These data suggest that injured nerve-derived PGE2 contributes to the maintenance of NeP at the chronic stage in aged rats. Chronically facilitating the synthesis of pain-related molecules in nociceptive DRG neurons is a novel mechanism underpinning the contribution of PGE2.
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Affiliation(s)
- Weiya Ma
- The Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada.
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Volunteer studies in pain research — Opportunities and challenges to replace animal experiments. Neuroimage 2008; 42:467-73. [DOI: 10.1016/j.neuroimage.2008.05.030] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2008] [Revised: 05/19/2008] [Accepted: 05/21/2008] [Indexed: 12/29/2022] Open
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Lundeberg T, Lund I. Is There a Role for Acupuncture in Endometriosis Pain, Or ‘endometrialgia’? Acupunct Med 2008; 26:94-110. [DOI: 10.1136/aim.26.2.94] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Endometriosis is a common cause of pelvic pain in women, many of whom suffer a progression of symptoms over their menstrual life. Symptoms may include combinations of abnormal visceral sensations and emotional distress. Endometriosis pain, or ‘endometrialgia’ often has a negative influence on the ability to work, on family relationships and sense of worth. Endometrialgia is often considered to be a homogeneous sensory entity, mediated by a specialised high threshold sensory system, which extends from the periphery through the spinal cord, brain stem and thalamus to the cerebral cortex. However, multiple mechanisms have been detected in the nervous system responsible for the pain including peripheral sensitisation, phenotypic switches, central sensitisation, ectopic excitability, structural reorganisation, decreased inhibition and increased facilitation, all of which may contribute to the pain. Although the causes of endometrialgia can differ (eg inflammatory, neuropathic and functional), they share some characteristics. Endometrialgia may be evoked by a low intensity, normally innocuous stimulus (allodynia), or it may be an exaggerated and prolonged response to a noxious stimulus (hyperalgesia). The pain may also be spontaneous in the absence of any apparent peripheral stimulus. Oestrogens and prostaglandins probably play key modulatory roles in endometriosis and endometrialgia. Consequently many of the current medical treatments for the condition include oral drugs, like non-steroid anti-inflammatory drugs, contraceptives, progestogens, androgenic agents, gonadotrophin releasing hormone analogues, as well as laparoscopic surgical excision of the endometriosis lesions. However, management of pain in women with endometriosis is currently inadequate for many. Possibly acupuncture and cognitive therapy may be used as an adjunct.
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Affiliation(s)
- Thomas Lundeberg
- Foundation for Acupuncture and Alternative Biological Treatment Methods Sabbatsbergs Hospital Stockholm, Sweden
| | - Iréne Lund
- Department of Physiology and Pharmacology Karolinska Institutet Stockholm, Sweden
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Does COX2-dependent PGE2 play a role in neuropathic pain? Neurosci Lett 2008; 437:165-9. [PMID: 18434017 DOI: 10.1016/j.neulet.2008.02.072] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2007] [Revised: 02/12/2008] [Accepted: 02/21/2008] [Indexed: 11/18/2022]
Abstract
Neuropathic pain (NeP) is a common chronic pain state with unmet medical needs. Due to poorly defined underlying mechanisms, current therapies for NeP are far from satisfactory. Mounting evidence suggests that long-term plasticity in pain signaling pathways underpins the pathogenesis of NeP. Inflammatory responses in injured nerves have been recognized as important events initially sensitizing nociceptive neurons and subsequently inducing long-term plasticity in the dorsal root ganglion. Inflammatory cells such as invading macrophages and Schwann cells produce a wide array of inflammatory mediators. Cyclooxygenase 2-dependent prostaglandin E2 (COX2/PGE2) is one of the important mediator abundantly produced in injured nerves and involved in the genesis of NeP. In this mini-review, we highlight possible novel mechanisms underlying the role of COX2/PGE2 in injured nerves in the genesis of NeP. Long lasting COX2/PGE2 in injured nerves may induce chronic effects on nociceptors to facilitate the synthesis of pain-related molecules by stimulating 'en passant' injured or spared axons. COX2/PGE2 may also induce chronic effects on local inflammatory cells in injured nerves to facilitate the synthesis of inflammatory mediators via autocrine and paracrine pathways. COX2/PGE2 in injured nerves and downstream PGE2 EP receptor signaling should be considered as therapeutic targets to more effectively treat chronic NeP.
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Watkins LR, Hutchinson MR, Milligan ED, Maier SF. "Listening" and "talking" to neurons: implications of immune activation for pain control and increasing the efficacy of opioids. BRAIN RESEARCH REVIEWS 2007; 56:148-69. [PMID: 17706291 PMCID: PMC2245863 DOI: 10.1016/j.brainresrev.2007.06.006] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2007] [Revised: 06/21/2007] [Accepted: 06/26/2007] [Indexed: 01/08/2023]
Abstract
It is recently become clear that activated immune cells and immune-like glial cells can dramatically alter neuronal function. By increasing neuronal excitability, these non-neuronal cells are now implicated in the creation and maintenance of pathological pain, such as occurs in response to peripheral nerve injury. Such effects are exerted at multiple sites along the pain pathway, including at peripheral nerves, dorsal root ganglia, and spinal cord. In addition, activated glial cells are now recognized as disrupting the pain suppressive effects of opioid drugs and contributing to opioid tolerance and opioid dependence/withdrawal. While this review focuses on regulation of pain and opioid actions, such immune-neuronal interactions are broad in their implications. Such changes in neuronal function would be expected to occur wherever immune-derived substances come in close contact with neurons.
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Affiliation(s)
- Linda R Watkins
- Department of Psychology and Center for Neuroscience, University of Colorado at Boulder, Boulder, CO 80309-0345, USA.
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Barclay J, Clark AK, Ganju P, Gentry C, Patel S, Wotherspoon G, Buxton F, Song C, Ullah J, Winter J, Fox A, Bevan S, Malcangio M. Role of the cysteine protease cathepsin S in neuropathic hyperalgesia. Pain 2007; 130:225-234. [PMID: 17250968 DOI: 10.1016/j.pain.2006.11.017] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2006] [Revised: 10/11/2006] [Accepted: 11/29/2006] [Indexed: 11/29/2022]
Abstract
Using a gene expression analysis approach we found that the mRNA encoding the lysosomal cysteine protease cathepsin S (CatS) was up-regulated in rat dorsal root ganglia (DRG) following peripheral nerve injury. CatS protein was expressed in infiltrating macrophages in DRG and near the site of injury. At both sites CatS expression progressively increased from day 3 to day 14 after injury. In naïve rats, intraplantar injection of activated rat recombinant (rr) CatS (0.3, 1 microg/rat) induced a mechanical hyperalgesia that developed within half-an-hour, diminished by 3h and was absent after 24h. Activated rrCathepsin B (CatB) and non-activated rrCatS injected intraplantarly at the same or higher doses than activated rrCatS had no effect on rat nociceptive thresholds. In nerve-injured rats, mechanical hyperalgesia, but not allodynia, was significantly reversed for up to 3h by systemic administration of a non-brain penetrant, irreversible CatS inhibitor (LHVS, 3-30 mg/kg s.c.). Depletion of peripheral macrophages by intravenous injection of liposome encapsulate clodronate (1ml, 5 mg/ml) partially reduced established mechanical hyperalgesia but not allodynia, and abolished the anti-hyperalgesic effect of LHVS. Our results demonstrate a pro-nociceptive effect of CatS and indicate that endogenous CatS released by peripheral macrophages contributes to the maintenance of neuropathic hyperalgesia following nerve injury.
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Affiliation(s)
- Jane Barclay
- Novartis Institutes for Biomedical Research, 5 Gower Place, London WC1E 6BS, UK Department of Functional Genomics, Novartis Institutes for Biomedical Research, 100 Technology Square, Cambridge, MA 02139, USA Wolfson CARD, King's College London, Guy's Campus, London SE1 1UL, UK
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