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Sandy-Hindmarch O, Molina-Alvarez M, Wiberg A, Furniss D, Schmid AB. Higher densities of T-lymphocytes in the subsynovial connective tissue of people with carpal tunnel syndrome. PLoS One 2024; 19:e0300046. [PMID: 38451901 PMCID: PMC10919581 DOI: 10.1371/journal.pone.0300046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 02/20/2024] [Indexed: 03/09/2024] Open
Abstract
Symptoms in people with carpal tunnel syndrome (CTS) are traditionally attributed to neural tissue, but recent studies suggest that the subsynovial connective tissue (SSCT) may also play a role in CTS. The SSCT undergoes fibrotic thickening which is generally described as "non-inflammatory" based on basic histology. This study uses immunohistochemistry to determine the presence of macrophages and T-cells within SSCT and their relationship with symptoms in people with CTS. SSCT was collected from twenty people with CTS and eight controls undergoing wrist fracture surgery. Immunohistochemical quantification of CD3+ T-cells and CD68+ macrophage densities as well as CD4+/CD8+ T-cell subpopulations were compared between groups using independent t-tests. Spearman correlations were used to identify associations between immune cell densities and CTS symptom scores. The density of CD3+ T-cells was significantly higher in SSCT of people with CTS compared to controls (CTS mean 26.7 (SD 13.7); controls 6.78 (6.3), p = 0.0005) while the density of CD68+ macrophages was lower (CTS mean 9.5 (SD 6.0); controls 17.7 (8.2), p = 0.0058). Neither CD68+ nor CD3+ cell densities correlated with symptom scores. In contrast to previous assumptions, our data show that the SSCT in the carpal tunnel in both people with CTS and controls is not devoid of immune cells. Whereas the higher density of CD68+ macrophages in control participants may be associated with their early recruitment after acute fracture, CD3+ cells within the SSCT may play a role in chronic CTS.
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Affiliation(s)
- Oliver Sandy-Hindmarch
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Miguel Molina-Alvarez
- Department of Basic Health Sciences, Area of Pharmacology, Nutrition and Bromatology, Universidad Rey Juan Carlos, Madrid, Spain
| | - Akira Wiberg
- Nuffield Department of Orthopaedics, Rheumatology, and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom
| | - Dominic Furniss
- Nuffield Department of Orthopaedics, Rheumatology, and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom
| | - Annina B. Schmid
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
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2
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Cherng JH, Chang SJ, Tsai HD, Chun CF, Fan GY, Reeves KD, Lam KHS, Wu YT. The Potential of Glucose Treatment to Reduce Reactive Oxygen Species Production and Apoptosis of Inflamed Neural Cells In Vitro. Biomedicines 2023; 11:1837. [PMID: 37509477 PMCID: PMC10376532 DOI: 10.3390/biomedicines11071837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 06/24/2023] [Accepted: 06/24/2023] [Indexed: 07/30/2023] Open
Abstract
Neuroinflammation is a key feature in the pathogenesis of entrapment neuropathies. Clinical trial evidence suggests that perineural injection of glucose in water at entrapment sites has therapeutic benefits beyond a mere mechanical effect. We previously demonstrated that 12.5-25 mM glucose restored normal metabolism in human SH-SYFY neuronal cells rendered metabolically inactive from TNF-α exposure, a common initiator of neuroinflammation, and reduced secondary elevation of inflammatory cytokines. In the present study, we measured the effects of glucose treatment on cell survival, ROS activity, gene-related inflammation, and cell cycle regulation in the presence of neurogenic inflammation. We exposed SH-SY5Y cells to 10 ng/mL of TNF-α for 24 h to generate an inflammatory environment, followed by 24 h of exposure to 3.125, 6.25, 12.5, and 25 mM glucose. Glucose exposure, particularly at 12.5 mM, preserved apoptotic SH-SY5Y cell survival following a neuroinflammatory insult. ROS production was substantially reduced, suggesting a ROS scavenging effect. Glucose treatment significantly increased levels of CREB, JNK, and p70S6K (p < 0.01), pointing to antioxidative and anti-inflammatory actions through components of the MAPK family and Akt pathways but appeared underpowered (n = 6) to reach significance for NF-κB, p38, ERK1/2, Akt, and STAT5 (p < 0.05). Cell regulation analysis indicated that glucose treatment recovered/restored function in cells arrested in the S or G2/M-phases. In summary, glucose exposure in vitro restores function in apoptotic nerves after TNF-α exposure via several mechanisms, including ROS scavenging and enhancement of MAPK family and Akt pathways. These findings suggest that glucose injection about entrapped peripheral nerves may have several favorable biochemical actions that enhance neuronal cell function.
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Affiliation(s)
- Juin-Hong Cherng
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei 11490, Taiwan
- Department and Graduate Institute of Biology and Anatomy, National Defense Medical Center, Taipei 11490, Taiwan
- Department of Biomedical Engineering, Chung Yuan Christian University, Taoyuan 320314, Taiwan
| | - Shu-Jen Chang
- Department and Graduate Institute of Biology and Anatomy, National Defense Medical Center, Taipei 11490, Taiwan
- Laboratory of Adult Stem Cell and Tissue Regeneration, National Defense Medical Center, Taipei 11490, Taiwan
| | - Hsin-Da Tsai
- Laboratory of Adult Stem Cell and Tissue Regeneration, National Defense Medical Center, Taipei 11490, Taiwan
| | - Chung-Fang Chun
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei 11490, Taiwan
| | - Gang-Yi Fan
- Department and Graduate Institute of Biology and Anatomy, National Defense Medical Center, Taipei 11490, Taiwan
- Laboratory of Adult Stem Cell and Tissue Regeneration, National Defense Medical Center, Taipei 11490, Taiwan
| | | | - King Hei Stanley Lam
- The Hong Kong Institute of Musculoskeletal Medicine, Hong Kong
- Department of Family Medicine, The Chinese University of Hong Kong, Hong Kong
- Department of Family Medicine, The University of Hong Kong, Hong Kong
- Center for Regional Anesthesia and Pain Medicine, Chung Shan Medical University Hospital, Taichung 402, Taiwan
| | - Yung-Tsan Wu
- Department of Physical Medicine and Rehabilitation, Tri-Service General Hospital, School of Medicine, National Defense Medical Center, Taipei 11490, Taiwan
- Integrated Pain Management Center, Tri-Service General Hospital, School of Medicine, National Defense Medical Center, Taipei 11490, Taiwan
- Department of Research and Development, School of Medicine, National Defense Medical Center, Taipei 11490, Taiwan
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Malik T, Malik A, Abd-Elsayed A. Pathophysiology of Work-Related Neuropathies. Biomedicines 2023; 11:1745. [PMID: 37371842 DOI: 10.3390/biomedicines11061745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 06/12/2023] [Accepted: 06/15/2023] [Indexed: 06/29/2023] Open
Abstract
Work-related injuries are common. The cost of these injuries is around USD 176 billion to USD 350 billion a year. A significant number of work-related injuries involve nerve damage or dysfunction. Injuries may heal with full recovery of function, but those involving nerve damage may result in significant loss of function or very prolonged recovery. While many factors can predispose a person to suffer nerve damage, in most cases, it is a multifactorial issue that involves both intrinsic and extrinsic factors. This makes preventing work-related injuries hard. To date, no evidence-based guidelines are available to clinicians to evaluate work-related nerve dysfunction. While the symptoms range from poor endurance to cramping to clear loss of motor and sensory functions, not all nerves are equally vulnerable. The common risk factors for nerve damage are a superficial location, a long course, an acute change in trajectory along the course, and coursing through tight spaces. The pathophysiology of acute nerve injury is well known, but that of chronic nerve injury is much less well understood. The two most common mechanisms of nerve injury are stretching and compression. Chronic mild to moderate compression is the most common mechanism of nerve injury and it elicits a characteristic response from Schwann cells, which is different from the one when nerve is acutely injured. It is important to gain a better understanding of work-related nerve dysfunction, both from health and from regulatory standpoints. Currently, management depends upon etiology of nerve damage, recovery is often poor if nerves are badly damaged or treatment is not instituted early. This article reviews the current pathophysiology of chronic nerve injury. Chronic nerve injury animal models have contributed a lot to our understanding but it is still not complete. Better understanding of chronic nerve injury pathology will result in identification of novel and more effective targets for pharmacological interventions.
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Affiliation(s)
- Tariq Malik
- Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, B6/319 CSC, Madison, WI 53792-3272, USA
| | - Ahmed Malik
- Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, B6/319 CSC, Madison, WI 53792-3272, USA
| | - Alaa Abd-Elsayed
- Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, B6/319 CSC, Madison, WI 53792-3272, USA
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Schmid AB, Fundaun J, Tampin B. [Entrapment neuropathies: a contemporary approach to pathophysiology, clinical assessment, and management : German version]. Schmerz 2021; 35:419-433. [PMID: 34505948 DOI: 10.1007/s00482-021-00584-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/16/2021] [Indexed: 10/20/2022]
Abstract
Entrapment neuropathies such as carpal tunnel syndrome, radiculopathies, or radicular pain are the most common peripheral neuropathies and also the most common cause for neuropathic pain. Despite their high prevalence, they often remain challenging to diagnose and manage in a clinical setting. Summarising the evidence from both preclinical and clinical studies, this review provides an update on the aetiology and pathophysiology of entrapment neuropathies. Potenzial mechanisms are put in perspective with clinical findings. The contemporary assessment is discussed and diagnostic pitfalls highlighted. The evidence for the noninvasive and surgical management of common entrapment neuropathies is summarised and future areas of research are identified.
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Affiliation(s)
- Annina B Schmid
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford University, West Wing Level 6, OX3 9DU, Oxford, Großbritannien.
| | - Joel Fundaun
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford University, West Wing Level 6, OX3 9DU, Oxford, Großbritannien.,High Country Physical Therapy, Laramie, WY, USA
| | - Brigitte Tampin
- Department of Physiotherapy, Sir Charles Gairdner Hospital, Perth, Westaustralien, Australien.,School of Physiotherapy and Exercise Science, Curtin University, Westaustralien, Australien.,Fakultät Wirtschafts- und Sozialwissenschaften, Hochschule Osnabrück, Osnabrück, Deutschland
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5
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Schmid AB, Fundaun J, Tampin B. Entrapment neuropathies: a contemporary approach to pathophysiology, clinical assessment, and management. Pain Rep 2020; 5:e829. [PMID: 32766466 PMCID: PMC7382548 DOI: 10.1097/pr9.0000000000000829] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 05/04/2020] [Accepted: 05/30/2020] [Indexed: 12/18/2022] Open
Abstract
Entrapment neuropathies such as carpal tunnel syndrome, radiculopathies, or radicular pain are the most common peripheral neuropathies and also the most common cause for neuropathic pain. Despite their high prevalence, they often remain challenging to diagnose and manage in a clinical setting. Summarising the evidence from both preclinical and clinical studies, this review provides an update on the aetiology and pathophysiology of entrapment neuropathies. Potential mechanisms are put in perspective with clinical findings. The contemporary assessment is discussed and diagnostic pitfalls highlighted. The evidence for the noninvasive and surgical management of common entrapment neuropathies is summarised and future areas of research are identified.
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Affiliation(s)
- Annina B. Schmid
- Nuffield Department of Clinical Neurosciences, Oxford University, Oxford, United Kingdom
| | - Joel Fundaun
- Nuffield Department of Clinical Neurosciences, Oxford University, Oxford, United Kingdom
- High Country Physical Therapy, Laramie, WY, USA
| | - Brigitte Tampin
- Department of Physiotherapy, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
- School of Physiotherapy and Exercise Science, Curtin University, Western Australia, Australia
- Faculty of Business Management and Social Sciences, Hochschule Osnabrück, University of Applied Sciences, Osnabrück, Germany
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6
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Van Steenwinckel J, Auvynet C, Sapienza A, Reaux-Le Goazigo A, Combadière C, Melik Parsadaniantz S. Stromal cell-derived CCL2 drives neuropathic pain states through myeloid cell infiltration in injured nerve. Brain Behav Immun 2015; 45:198-210. [PMID: 25449579 DOI: 10.1016/j.bbi.2014.10.016] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 10/18/2014] [Accepted: 10/18/2014] [Indexed: 12/24/2022] Open
Abstract
Neuropathic pain resulting from peripheral nerve injury involves many persistent neuroinflammatory processes including inflammatory chemokines that control leukocyte trafficking and activate resident cells. Several studies have shown that CCL2 chemokine, a potent attractant of monocytes, and its cognate receptor, CCR2, play a critical role in regulating nociceptive processes during neuropathic pain. However, the role of CCL2 in peripheral leukocyte infiltration-associated neuropathic pain remains poorly understood. In particular, the contribution of individual CCL2-expressing cell populations (i.e. stromal and leukocytes) to immune cell recruitment into the injured nerve has not been established. Here, in preclinical model of peripheral neuropathic pain (i.e. chronic constriction injury of the sciatic nerve), we have demonstrated that, CCL2 content was increased specifically in nerve fibers. This upregulation of CCL2 correlated with local monocyte/macrophage infiltration and pain processing. Furthermore, sciatic intraneural microinjection of CCL2 in naïve animals triggered long-lasting pain behavior associated with local monocyte/macrophage recruitment. Using a specific CCR2 antagonist and mice with a CCL2 genetic deletion, we have also established that the CCL2/CCR2 axis drives monocyte/macrophage infiltration and pain hypersensitivity in the CCI model. Finally, specific deletion of CCL2 in stromal or immune cells respectively using irradiated bone marrow-chimeric CCI mice demonstrated that stromal cell-derived CCL2 (in contrast to CCL2 immune cell-derived) tightly controls monocyte/macrophage recruitment into the lesion and plays a major role in the development of neuropathic pain. These findings demonstrate that in chronic pain states, CCL2 expressed by sciatic nerve cells predominantly drove local neuro-immune interactions and pain-related behavior through CCR2 signaling.
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Affiliation(s)
- Juliette Van Steenwinckel
- UMR 1141 INSERM, Hôpital Robert Debré, F-75019, Paris, France; Université Paris Diderot, Faculté de Médecine, F-75019, Paris, France; PremUP, 75014 Paris, France
| | - Constance Auvynet
- Sorbonne Universités, UPMC Université Paris 06, CR7, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris). 91 Bd de l'hôpital, F-75013, Paris, France; Inserm, U1135, CIMI-Paris, 91 Bd de l'hôpital, F-75013, Paris, France; CNRS, ERL 8255, CIMI-Paris, 91 Bd de l'hôpital, F-75013, Paris, France
| | - Anaïs Sapienza
- Sorbonne Universités, UPMC Université Paris 06, Institut de la vision, équipe S12, 17 rue Moreau, F-75012, Paris, France; UMR_S 968 INSERM, 17 rue Moreau, F-75012, Paris, France; UMR 7210 CNRS, 17 rue Moreau, F-75012, Paris, France
| | - Annabelle Reaux-Le Goazigo
- Sorbonne Universités, UPMC Université Paris 06, Institut de la vision, équipe S12, 17 rue Moreau, F-75012, Paris, France; UMR_S 968 INSERM, 17 rue Moreau, F-75012, Paris, France; UMR 7210 CNRS, 17 rue Moreau, F-75012, Paris, France
| | - Christophe Combadière
- Sorbonne Universités, UPMC Université Paris 06, CR7, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris). 91 Bd de l'hôpital, F-75013, Paris, France; Inserm, U1135, CIMI-Paris, 91 Bd de l'hôpital, F-75013, Paris, France; CNRS, ERL 8255, CIMI-Paris, 91 Bd de l'hôpital, F-75013, Paris, France
| | - Stéphane Melik Parsadaniantz
- Sorbonne Universités, UPMC Université Paris 06, Institut de la vision, équipe S12, 17 rue Moreau, F-75012, Paris, France; UMR_S 968 INSERM, 17 rue Moreau, F-75012, Paris, France; UMR 7210 CNRS, 17 rue Moreau, F-75012, Paris, France.
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7
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Geuna S. The sciatic nerve injury model in pre-clinical research. J Neurosci Methods 2015; 243:39-46. [PMID: 25629799 DOI: 10.1016/j.jneumeth.2015.01.021] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 01/15/2015] [Accepted: 01/16/2015] [Indexed: 12/15/2022]
Abstract
In the pre-clinical view, the study of peripheral nerve repair and regeneration still needs to be carried out in animal models due to the structural complexity of this organ which can be only partly simulated in vitro. The far most used experimental model is based on the injury of the sciatic nerve, the largest nerve trunk in mammals. In this paper, the potential application of the sciatic nerve injury model in pre-clinical research is critically reviewed. This paper is aimed at helping researchers in properly employing this in vivo model for the study of nerve repair and regeneration as well as interpreting the results in a clinical translation perspective.
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Affiliation(s)
- Stefano Geuna
- Neuroscience Institute of the Cavalieri Ottolenghi Foundation & Department of Clinical and Biological Sciences, University of Turin, Italy.
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8
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Barbe MF, Gallagher S, Massicotte VS, Tytell M, Popoff SN, Barr-Gillespie AE. The interaction of force and repetition on musculoskeletal and neural tissue responses and sensorimotor behavior in a rat model of work-related musculoskeletal disorders. BMC Musculoskelet Disord 2013; 14:303. [PMID: 24156755 PMCID: PMC3924406 DOI: 10.1186/1471-2474-14-303] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 10/22/2013] [Indexed: 12/01/2022] Open
Abstract
Background We examined the relationship of musculoskeletal risk factors underlying force and repetition on tissue responses in an operant rat model of repetitive reaching and pulling, and if force x repetition interactions were present, indicative of a fatigue failure process. We examined exposure-dependent changes in biochemical, morphological and sensorimotor responses occurring with repeated performance of a handle-pulling task for 12 weeks at one of four repetition and force levels: 1) low repetition with low force, 2) high repetition with low force, 3) low repetition with high force, and 4) high repetition with high force (HRHF). Methods Rats underwent initial training for 4–6 weeks, and then performed one of the tasks for 12 weeks, 2 hours/day, 3 days/week. Reflexive grip strength and sensitivity to touch were assayed as functional outcomes. Flexor digitorum muscles and tendons, forelimb bones, and serum were assayed using ELISA for indicators of inflammation, tissue stress and repair, and bone turnover. Histomorphometry was used to assay macrophage infiltration of tissues, spinal cord substance P changes, and tissue adaptative or degradative changes. MicroCT was used to assay bones for changes in bone quality. Results Several force x repetition interactions were observed for: muscle IL-1alpha and bone IL-1beta; serum TNFalpha, IL-1alpha, and IL-1beta; muscle HSP72, a tissue stress and repair protein; histomorphological evidence of tendon and cartilage degradation; serum biomarkers of bone degradation (CTXI) and bone formation (osteocalcin); and morphological evidence of bone adaptation versus resorption. In most cases, performance of the HRHF task induced the greatest tissue degenerative changes, while performance of moderate level tasks induced bone adaptation and a suggestion of muscle adaptation. Both high force tasks induced median nerve macrophage infiltration, spinal cord sensitization (increased substance P), grip strength declines and forepaw mechanical allodynia by task week 12. Conclusions Although not consistent in all tissues, we found several significant interactions between the critical musculoskeletal risk factors of force and repetition, consistent with a fatigue failure process in musculoskeletal tissues. Prolonged performance of HRHF tasks exhibited significantly increased risk for musculoskeletal disorders, while performance of moderate level tasks exhibited adaptation to task demands.
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Affiliation(s)
- Mary F Barbe
- Department of Anatomy and Cell Biology, Temple University School of Medicine, 3500 North Broad St, Philadelphia 19140, PA, USA.
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Local and remote immune-mediated inflammation after mild peripheral nerve compression in rats. J Neuropathol Exp Neurol 2013; 72:662-80. [PMID: 23771220 DOI: 10.1097/nen.0b013e318298de5b] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
After experimental nerve injuries that extensively disrupt axons, such as chronic constriction injury, immune cells invade the nerve, related dorsal root ganglia (DRGs), and spinal cord, leading to hyperexcitability, raised sensitivity, and pain. Entrapment neuropathies, such as carpal tunnel syndrome, involve minimal axon damage, but patients often report widespread symptoms. To understand the underlying pathology, a tube was placed around the sciatic nerve in 8-week-old rats, leading to progressive mild compression as the animals grew. Immunofluorescence was used to examine myelin and axonal integrity, glia, macrophages, and T lymphocytes in the nerve, L5 DRGs, and spinal cord after 12 weeks. Tubes that did not constrict the nerve when applied caused extensive and ongoing loss of myelin, together with compromise of small-, but not large-, diameter axons. Macrophages and T lymphocytes infiltrated the nerve and DRGs. Activated glia proliferated in DRGs but not in spinal cord. Histologic findings were supported by clinical hyperalgesia to blunt pressure and cold allodynia. Tubes that did not compress the nerve induced only minor local inflammation. Thus, progressive mild nerve compression resulted in chronic local and remote immune-mediated inflammation depending on the degree of compression. Such neuroinflammation may explain the widespread symptoms in patients with entrapment neuropathies.
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Abstract
Peripheral nerve injuries are common conditions, with broad-ranging groups of symptoms depending on the severity and nerves involved. Although much knowledge exists on the mechanisms of injury and regeneration, reliable treatments that ensure full functional recovery are scarce. This review aims to summarize various ways these injuries are classified in light of decades of research on peripheral nerve injury and regeneration.
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Affiliation(s)
- Ron M G Menorca
- School of Medicine and Dentistry, University of Rochester Medical Center, 601 Elmwood Avenue, Box 665, Rochester, NY 14642, USA
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11
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Chang YW, Winkelstein BA. Schwann Cell Proliferation and Macrophage Infiltration Are Evident at Day 14 after Painful Cervical Nerve Root Compression in the Rat. J Neurotrauma 2011; 28:2429-38. [DOI: 10.1089/neu.2011.1918] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Yu-Wen Chang
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Beth A. Winkelstein
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania
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12
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Chew DJ, Carlstedt T, Shortland PJ. A comparative histological analysis of two models of nerve root avulsion injury in the adult rat. Neuropathol Appl Neurobiol 2011; 37:613-32. [DOI: 10.1111/j.1365-2990.2011.01176.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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13
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Dubový P. Wallerian degeneration and peripheral nerve conditions for both axonal regeneration and neuropathic pain induction. Ann Anat 2011; 193:267-75. [PMID: 21458249 DOI: 10.1016/j.aanat.2011.02.011] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2011] [Revised: 02/15/2011] [Accepted: 02/16/2011] [Indexed: 12/29/2022]
Abstract
Wallerian degeneration is a cascade of stereotypical events in reaction to injury of nerve fibres. These events consist of cellular and molecular alterations, including macrophage invasion, activation of Schwann cells, as well as neurotrophin and cytokine upregulation. This review focuses on cellular and molecular changes distal to various types of peripheral nerve injury which simultaneously contribute to axonal regeneration and neuropathic pain induction. In addition to the stereotypical events of Wallerian degeneration, various types of nerve damage provide different conditions for both axonal regeneration and neuropathic pain induction. Wallerian degeneration of injured peripheral nerve is associated with an inflammatory response including rapid upregulation of the immune signal molecules like cytokines, chemokines and transcription factors with both beneficial and detrimental effects on nerve regeneration or neuropathic pain induction. A better understanding of the molecular interactions between the immune system and peripheral nerve injury would open the possibility for targeting these inflammatory mediators in therapeutic interventions. Understanding the pleiotropic effects of cytokines/chemokines, however, requires investigating their highly specific pathways and precise points of action.
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Affiliation(s)
- Petr Dubový
- Department of Anatomy, Division of Neuroanatomy, Faculty of Medicine and Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 3, Brno, Czech Republic.
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14
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Frieboes LR, Palispis WA, Gupta R. Nerve compression activates selective nociceptive pathways and upregulates peripheral sodium channel expression in Schwann cells. J Orthop Res 2010; 28:753-61. [PMID: 20014316 DOI: 10.1002/jor.21047] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Chronic nerve compression (CNC) injuries, such as carpal tunnel syndrome, are common musculoskeletal conditions that affect patients with debilitating loss of sensory function and pain. Although early detection and treatment are important, our understanding of pain-related molecular mechanisms remains largely unclear. Here we investigate these mechanisms using an animal model for CNC injury. To confirm that CNC injury induces pain, we assessed expression of c-fos, a gene that is rapidly expressed in spinal sensory afferents in response to painful peripheral stimuli, and TNF-alpha and IL-6, two proinflammatory cytokines that are crucial to development of inflammatory-mediated pain. Results show c-fos upregulation 1-2 weeks postinjury in the absence of TNF-alpha or IL-6 expression, indicating increased neural sensitivity without an inflammatory response. This is consistent with previous studies that showed no morphologic evidence of inflammation in the CNC model. Surprisingly, we also found de novo expression of Na(V)1.8, a sodium channel linked to the development of neuropathic pain, in endoneurial Schwann cells following injury. Until now, Na(V)1.8 expression was thought to be restricted to sensory neurons. CNC injury appears to be a unique model of noninflammatory neuropathic pain. Further investigation of the underlying molecular basis could yield promising targets for early diagnosis and treatment.
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Affiliation(s)
- Laura Rummler Frieboes
- Department of Biomedical Engineering, University of California Irvine, 2226 Gillespie Neuroscience Research Facility, Irvine, California 92697, USA
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15
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Dinh P, Hazel A, Palispis W, Suryadevara S, Gupta R. Functional assessment after sciatic nerve injury in a rat model. Microsurgery 2009; 29:644-9. [DOI: 10.1002/micr.20685] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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16
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Pham K, Gupta R. Understanding the mechanisms of entrapment neuropathies. Review article. Neurosurg Focus 2009; 26:E7. [PMID: 19435447 DOI: 10.3171/foc.2009.26.2.e7] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Compression neuropathies are highly prevalent, debilitating conditions with variable functional recovery following surgical decompression. Due to the limited amount of human nerve tissue available for analysis, a number of animal models have been created to help investigators understand the molecular and cellular pathogenesis of chronic nerve compression (CNC) injury. Evidence suggests that CNC injury induces concurrent Schwann cell proliferation and apoptosis in the early stages of the disorder. These proliferating Schwann cells downregulate myelin proteins, leading to local demyelination and remyelination in the region of injury. In addition, the downregulation of myelin proteins, in particular myelin-associated glycoprotein, allows for axonal sprouting. Interestingly, these changes occur in the absence of both morphological and electrophysiological evidence of axonal damage. This is in direct contrast to acute injuries, such as transection or crush, which are characterized by axonal injury followed by Wallerian degeneration. Because the accepted trigger for Schwann cell dedifferentiation is axonal injury, an alternate mechanism for Schwann response must exist in CNC injury. In vitro studies of pure Schwann cells have shown that these cells can respond directly to mechanical stimuli by downregulating myelin proteins and proliferating. These studies suggest that although the reciprocal relationship between neurons and glial cells is maintained, chronic nerve compression injury is a Schwann cell-mediated disease.
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Affiliation(s)
- Khoa Pham
- Department of Orthopaedic Surgery, University of California, Irvine, California, USA
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Mozaffar T, Strandberg E, Abe K, Hilgenberg LG, Smith MA, Gupta R. Neuromuscular junction integrity after chronic nerve compression injury. J Orthop Res 2009; 27:114-9. [PMID: 18655131 PMCID: PMC2670070 DOI: 10.1002/jor.20704] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Chronic nerve compression injuries (CNC) are progressive demyelinating disorders characterized by a gradual decline of the nerve conduction velocity (NCV) in the affected nerve region. CNC injury induces a robust Schwann cell response with axonal sprouting, but without morphologic evidence of axonal injury. We hypothesize that early CNC injury occurs without damage to neuromuscular junction of motor axons. A well-established animal model was used to assess for damage to motor axons. As sprouting is considered a hallmark of regeneration during and after axonal degeneration and sprouting was confirmed visually at 2 weeks in CNC animals, we assessed for axonal degeneration in motor nerves after CNC by evaluating the integrity of the neuromuscular junction. NCV exhibited a gradual progressive decline consistent with the human condition. Compound motor action potential amplitudes decreased slightly immediately and plateaued, indicating that there was not sustained and increasing axonal loss. Sprouting was confirmed using immunofluorescence and by an increase in number of unmyelinated axons and Remak bundles. Blind analysis of the neuromuscular junction showed no difference between control and CNC images, indicating that there was no evidence for end-unit axonal loss in the soleus muscle. Because the progressive decline in NCV was not paired with a similar progressive decline in amplitude, it is likely that axonal loss is not responsible for slowing of action potentials. Blind analysis of the neuromuscular junction provides further evidence that the axonal sprouting seen early after CNC injury is not a consequence of axonal degeneration in the motor nerves.
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Affiliation(s)
- Tahseen Mozaffar
- Department of Neurology, 101 The City Drive South, Bldg. 22 C, Route 13, Orange, California 92868,Peripheral Nerve Research Laboratory, 2226 Gillespie Neuroscience Research Facility, University of California, Irvine, Calfornia 92697-4292
| | - Erika Strandberg
- Department of Orthopaedics, 101 The City Drive South, Pavilion III, Orange, California 92868,Peripheral Nerve Research Laboratory, 2226 Gillespie Neuroscience Research Facility, University of California, Irvine, Calfornia 92697-4292
| | - Kazuko Abe
- Department of Orthopaedics, 101 The City Drive South, Pavilion III, Orange, California 92868,Peripheral Nerve Research Laboratory, 2226 Gillespie Neuroscience Research Facility, University of California, Irvine, Calfornia 92697-4292
| | - Lutz G. Hilgenberg
- Department of Anatomy and Neurobiology, 110 Irvine Hall, University of California, Irvine, CA 92697-1280
| | - Martin A. Smith
- Department of Anatomy and Neurobiology, 110 Irvine Hall, University of California, Irvine, CA 92697-1280
| | - Ranjan Gupta
- Department of Orthopaedics, 101 The City Drive South, Pavilion III, Orange, California 92868,Department of Anatomy and Neurobiology, 110 Irvine Hall, University of California, Irvine, CA 92697-1280,Peripheral Nerve Research Laboratory, 2226 Gillespie Neuroscience Research Facility, University of California, Irvine, Calfornia 92697-4292
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Rothman SM, Huang Z, Lee KE, Weisshaar CL, Winkelstein BA. Cytokine mRNA expression in painful radiculopathy. THE JOURNAL OF PAIN 2008; 10:90-9. [PMID: 18848809 DOI: 10.1016/j.jpain.2008.07.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2008] [Revised: 07/18/2008] [Accepted: 07/29/2008] [Indexed: 01/01/2023]
Abstract
UNLABELLED Inflammatory cytokines contribute to lumbar radiculopathy. Regulation of cytokines for transient cervical injuries, with or without longer-lasting inflammation, remains to be defined. The C7 root in the rat underwent compression (10gf), chromic gut suture exposure (chr), or their combination (10gf+chr). Ipsilateral C7 spinal cord and dorsal root ganglia (DRG) were harvested at 1 hour after injury for real-time PCR analysis of IL-1beta, IL-6, and TNF-alpha. Cytokine mRNA increased after all 3 injuries. TNF-alpha mRNA in the DRG was significantly increased over sham after 10gf+chr (P = .026). Spinal IL-1beta was significantly increased over sham after 10gf and 10gf+chr (P < .024); IL-6 was significantly increased after 10gf+chr (P < .024). In separate studies, the soluble TNF-alpha receptor was administered at injury and again at 6 hours in all injury paradigms. Allodynia was assessed and tissue samples were harvested for cytokine PCR. Allodynia significantly decreased with receptor administration for 10gf and 10gf+chr (P < .005). Treatment also significantly decreased IL-1beta and TNF-alpha mRNA in the DRG for 10gf+chr (P < .028) at day 1. Results indicate an acute, robust cytokine response in cervical nerve root injury with varying patterns, dependent on injury type, and that early increases in TNF-alpha mRNA in the DRG may drive pain-related signaling for transient cervical injuries. PERSPECTIVE Inflammatory cytokine mRNA in the DRG and spinal cord are defined after painful cervical nerve root injury. Studies describe a role for TNF-alpha in mediating behavioral sensitivity and inflammatory cytokines in transient painful radiculopathy. Results outline an early response of inflammatory cytokine upregulation in cervical pain.
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Affiliation(s)
- Sarah M Rothman
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6321, USA
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Gray M, Palispis W, Popovich PG, van Rooijen N, Gupta R. Macrophage depletion alters the blood-nerve barrier without affecting Schwann cell function after neural injury. J Neurosci Res 2007; 85:766-77. [PMID: 17266098 DOI: 10.1002/jnr.21166] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Previous work has shown that, during the early phases of chronic nerve compression (CNC) injury, axonal pathology is absent while Schwann cells undergo a dramatic process of cellular turnover with marked proliferation. It is known that macrophages may release Schwann cell mitogens, so we sought to explore the role of macrophages in CNC injury by selectively depleting the population of hematogenously derived macrophages in nerves undergoing CNC injury by injecting clodronate liposomes at days 1, 3, and 6 postinjury and evaluating both the integrity of the blood-nerve barrier (BNB) and Schwann cell function. Integrity of the BNB was evaluated by intravenously injecting Evans blue albumin (EBA), and Schwann cell number was determined via stereologic techniques. The BNB was clearly altered by 2 weeks postinjury and continued to disintegrate at later time points. Macrophage depletion attenuated this response at all observed time points. Quantification of Schwann cell nuclei in CNC nerves showed no differences between compressed sections of macrophage-depleted and nondepleted animals. Although macrophages are largely responsible for the increased vascular permeability associated with CNC injury, it is likely that the Schwann cell response to CNC injury is not influenced by macrophage-derived mitogenic signals but rather must be mediated via alternative mechanisms.
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Affiliation(s)
- Michael Gray
- Department of Orthopaedic Surgery, University of California, Irvine, Irvine, California, USA
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