1
|
Mehling K, Becker J, Chen J, Scriba S, Kindl G, Jakubietz R, Sommer C, Hartmannsberger B, Rittner HL. Bilateral deficiency of Meissner corpuscles and papillary microvessels in patients with acute complex regional pain syndrome. Pain 2024:00006396-990000000-00525. [PMID: 38335004 DOI: 10.1097/j.pain.0000000000003168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 11/29/2023] [Indexed: 02/10/2024]
Abstract
ABSTRACT Complex regional pain syndrome (CRPS) presents postinjury with disproportionate pain and neuropathic, autonomic, motor symptoms, and skin texture affection. However, the origin of these multiplex changes is unclear. Skin biopsies offer a window to analyze the somatosensory and vascular system as well as skin trophicity with their protecting barriers. In previous studies, barrier-protective exosomal microRNAs were altered in CRPS. We here postulated that tissue architecture and barrier proteins are already altered at the beginning of CRPS. We analyzed ipsilateral and contralateral skin biopsies of 20 fully phenotyped early CRPS patients compared with 20 age- and sex-matched healthy controls. We established several automated unbiased methods to comprehensively analyze microvessels and somatosensory receptors as well as barrier proteins, including claudin-1, claudin-5, and claudin-19. Meissner corpuscles in the skin were bilaterally reduced in acute CRPS patients with some of them lacking these completely. The number of Merkel cells and the intraepidermal nerve fiber density were not different between the groups. Dermal papillary microvessels were bilaterally less abundant in CRPS, especially in patients with allodynia. Barrier proteins in keratinocytes, perineurium of dermal nerves, Schwann cells, and papillary microvessels were not affected in early CRPS. Bilateral changes in the tissue architecture in early CRPS might indicate a predisposition for CRPS that manifests after injury. Further studies should evaluate whether these changes might be used to identify risk patients for CRPS after trauma and as biomarkers for outcome.
Collapse
Affiliation(s)
- Katharina Mehling
- Department of Anesthesiology, Intensive Care, Emergency and Pain Medicine, Center for Interdisciplinary Pain Medicine, University Hospital Würzburg, Würzburg, Germany
| | - Juliane Becker
- Department of Anesthesiology, Intensive Care, Emergency and Pain Medicine, Center for Interdisciplinary Pain Medicine, University Hospital Würzburg, Würzburg, Germany
| | - Jeremy Chen
- Department of Anesthesiology, Intensive Care, Emergency and Pain Medicine, Center for Interdisciplinary Pain Medicine, University Hospital Würzburg, Würzburg, Germany
| | - Sabrina Scriba
- Department of Anesthesiology, Intensive Care, Emergency and Pain Medicine, Center for Interdisciplinary Pain Medicine, University Hospital Würzburg, Würzburg, Germany
| | - Gudrun Kindl
- Department of Anesthesiology, Intensive Care, Emergency and Pain Medicine, Center for Interdisciplinary Pain Medicine, University Hospital Würzburg, Würzburg, Germany
| | - Rafael Jakubietz
- Department Surgery II, University Hospital Würzburg, Würzburg, Germany
| | - Claudia Sommer
- Department of Neurology, University Hospital Würzburg, Würzburg, Germany
| | - Beate Hartmannsberger
- Department of Anesthesiology, Intensive Care, Emergency and Pain Medicine, Center for Interdisciplinary Pain Medicine, University Hospital Würzburg, Würzburg, Germany
| | - Heike L Rittner
- Department of Anesthesiology, Intensive Care, Emergency and Pain Medicine, Center for Interdisciplinary Pain Medicine, University Hospital Würzburg, Würzburg, Germany
| |
Collapse
|
2
|
Biţă CE, Scorei IR, Vreju AF, Muşetescu AE, Mogoşanu GD, Biţă A, Dinescu VC, Dinescu ŞC, Criveanu C, Bărbulescu AL, Florescu A, Ciurea PL. Microbiota-Accessible Boron-Containing Compounds in Complex Regional Pain Syndrome. MEDICINA (KAUNAS, LITHUANIA) 2023; 59:1965. [PMID: 38004014 PMCID: PMC10673453 DOI: 10.3390/medicina59111965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 10/20/2023] [Accepted: 11/06/2023] [Indexed: 11/26/2023]
Abstract
The microbiota-gut-brain axis has garnered increasing attention in recent years for its role in various health conditions, including neuroinflammatory disorders like complex regional pain syndrome (CRPS). CRPS is a debilitating condition characterized by chronic neuropathic pain, and its etiology and pathophysiology remain elusive. Emerging research suggests that alterations in the gut microbiota composition and function could play a significant role in CRPS development and progression. Our paper explores the implications of microbiota in CRPS and the potential therapeutic role of boron (B). Studies have demonstrated that individuals with CRPS often exhibit dysbiosis, with imbalances in beneficial and pathogenic gut bacteria. Dysbiosis can lead to increased gut permeability and systemic inflammation, contributing to the chronic pain experienced in CRPS. B, an essential trace element, has shown promise in modulating the gut microbiome positively and exerting anti-inflammatory effects. Recent preclinical and clinical studies suggest that B supplementation may alleviate neuropathic pain and improve CRPS symptoms by restoring microbiota balance and reducing inflammation. Our review highlights the complex interplay between microbiota, inflammation, and neuropathic pain in CRPS and underscores the potential of B as a novel therapeutic approach to target the microbiota-gut-brain axis, offering hope for improved management of this challenging condition.
Collapse
Affiliation(s)
- Cristina Elena Biţă
- Department of Rheumatology, University of Medicine and Pharmacy of Craiova, 2 Petru Rareş Street, 200349 Craiova, Romania; (C.E.B.); (A.F.V.); (A.E.M.); (Ş.C.D.); (C.C.); (A.L.B.); (A.F.); (P.L.C.)
| | - Ion Romulus Scorei
- Department of Biochemistry, BioBoron Research Institute, S.C. Natural Research S.R.L., 31B Dunării Street, 207465 Podari, Romania
| | - Ananu Florentin Vreju
- Department of Rheumatology, University of Medicine and Pharmacy of Craiova, 2 Petru Rareş Street, 200349 Craiova, Romania; (C.E.B.); (A.F.V.); (A.E.M.); (Ş.C.D.); (C.C.); (A.L.B.); (A.F.); (P.L.C.)
| | - Anca Emanuela Muşetescu
- Department of Rheumatology, University of Medicine and Pharmacy of Craiova, 2 Petru Rareş Street, 200349 Craiova, Romania; (C.E.B.); (A.F.V.); (A.E.M.); (Ş.C.D.); (C.C.); (A.L.B.); (A.F.); (P.L.C.)
| | - George Dan Mogoşanu
- Department of Pharmacognosy & Phytotherapy, Faculty of Pharmacy, University of Medicine and Pharmacy of Craiova, 2 Petru Rareş Street, 200349 Craiova, Romania; (G.D.M.); (A.B.)
| | - Andrei Biţă
- Department of Pharmacognosy & Phytotherapy, Faculty of Pharmacy, University of Medicine and Pharmacy of Craiova, 2 Petru Rareş Street, 200349 Craiova, Romania; (G.D.M.); (A.B.)
| | - Venera Cristina Dinescu
- Department of Health Promotion and Occupational Medicine, University of Medicine and Pharmacy of Craiova, 2 Petru Rareş Street, 200349 Craiova, Romania;
| | - Ştefan Cristian Dinescu
- Department of Rheumatology, University of Medicine and Pharmacy of Craiova, 2 Petru Rareş Street, 200349 Craiova, Romania; (C.E.B.); (A.F.V.); (A.E.M.); (Ş.C.D.); (C.C.); (A.L.B.); (A.F.); (P.L.C.)
| | - Cristina Criveanu
- Department of Rheumatology, University of Medicine and Pharmacy of Craiova, 2 Petru Rareş Street, 200349 Craiova, Romania; (C.E.B.); (A.F.V.); (A.E.M.); (Ş.C.D.); (C.C.); (A.L.B.); (A.F.); (P.L.C.)
| | - Andreea Lili Bărbulescu
- Department of Rheumatology, University of Medicine and Pharmacy of Craiova, 2 Petru Rareş Street, 200349 Craiova, Romania; (C.E.B.); (A.F.V.); (A.E.M.); (Ş.C.D.); (C.C.); (A.L.B.); (A.F.); (P.L.C.)
| | - Alesandra Florescu
- Department of Rheumatology, University of Medicine and Pharmacy of Craiova, 2 Petru Rareş Street, 200349 Craiova, Romania; (C.E.B.); (A.F.V.); (A.E.M.); (Ş.C.D.); (C.C.); (A.L.B.); (A.F.); (P.L.C.)
| | - Paulina Lucia Ciurea
- Department of Rheumatology, University of Medicine and Pharmacy of Craiova, 2 Petru Rareş Street, 200349 Craiova, Romania; (C.E.B.); (A.F.V.); (A.E.M.); (Ş.C.D.); (C.C.); (A.L.B.); (A.F.); (P.L.C.)
| |
Collapse
|
3
|
Rupp A, Young E, Chadwick AL. Low-dose naltrexone's utility for non-cancer centralized pain conditions: a scoping review. PAIN MEDICINE (MALDEN, MASS.) 2023; 24:1270-1281. [PMID: 37302106 PMCID: PMC10628981 DOI: 10.1093/pm/pnad074] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 05/24/2023] [Accepted: 06/02/2023] [Indexed: 06/13/2023]
Abstract
BACKGROUND At low doses, naltrexone (LDN) has been shown to modulate inflammation through the interruption of microglial cell activation within the central nervous system. One of the most likely contributors to centralized pain is changes in microglial cell processing. Therefore, it has been postulated that LDN can be used to manage patients with pain resulting from central sensitization due to this relationship. This scoping review aims to synthesize the relevant study data for LDN as a novel treatment strategy for various centralized pain conditions. METHODS A comprehensive literature search was conducted in PubMed, Embase, and Google Scholar, guided by the Scale for Assessment of Narrative Review Articles (SANRA) criteria. RESULTS Forty-seven studies related to centralized pain conditions were identified. Many of the studies were case reports/series and narrative reviews, but a few randomized control trials have been conducted. Overall, the body of evidence revealed improvement in patient-reported pain severity and in outcomes related to hyperalgesia, physical function, quality of life, and sleep. Variability in dosing paradigms and the time to patient response was present in the reviewed studies. CONCLUSIONS Evidence synthesized for this scoping review supports the ongoing use of LDN for the treatment of refractory pain in various centralized chronic pain conditions. Upon review of the currently available published studies, it is apparent that further high-quality, well-powered randomized control trials need to be conducted to establish efficacy, standardization for dosing, and response times. In summary, LDN continues to offer promising results in the management of pain and other distressing symptoms in patients with chronic centralized pain conditions.
Collapse
Affiliation(s)
- Adam Rupp
- Department of Physical Medicine and Rehabilitation, University of Kansas Medical Center, Kansas City, KS 66160, United States
| | - Erin Young
- Department of Anesthesiology, University of Kansas Medical Center, Kansas City, KS 66160, United States
| | - Andrea L Chadwick
- Department of Anesthesiology, University of Kansas Medical Center, Kansas City, KS 66160, United States
| |
Collapse
|
4
|
Jia X, Li Z, Shen X, Zhang Y, Zhang L, Zhang L. High-intensity swimming alleviates nociception and neuroinflammation in a mouse model of chronic post-ischemia pain by activating the resolvin E1-chemerin receptor 23 axis in the spinal cord. Neural Regen Res 2023; 18:2535-2544. [PMID: 37282487 PMCID: PMC10360102 DOI: 10.4103/1673-5374.371373] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023] Open
Abstract
Physical exercise effectively alleviates chronic pain associated with complex regional pain syndrome type-I. However, the mechanism of exercise-induced analgesia has not been clarified. Recent studies have shown that the specialized pro-resolving lipid mediator resolvin E1 promotes relief of pathologic pain by binding to chemerin receptor 23 in the nervous system. However, whether the resolvin E1-chemerin receptor 23 axis is involved in exercise-induced analgesia in complex regional pain syndrome type-I has not been demonstrated. In the present study, a mouse model of chronic post-ischemia pain was established to mimic complex regional pain syndrome type-I and subjected to an intervention involving swimming at different intensities. Chronic pain was reduced only in mice that engaged in high-intensity swimming. The resolvin E1-chemerin receptor 23 axis was clearly downregulated in the spinal cord of mice with chronic pain, while high-intensity swimming restored expression of resolvin E1 and chemerin receptor 23. Finally, shRNA-mediated silencing of chemerin receptor 23 in the spinal cord reversed the analgesic effect of high-intensity swimming exercise on chronic post-ischemic pain and the anti-inflammatory polarization of microglia in the dorsal horn of the spinal cord. These findings suggest that high-intensity swimming can decrease chronic pain via the endogenous resolvin E1-chemerin receptor 23 axis in the spinal cord.
Collapse
Affiliation(s)
- Xin Jia
- Department of Neurology and Neurological Rehabilitation, Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Medicine, Tongji University, Shanghai, China
| | - Ziyang Li
- Department of Neurology and Neurological Rehabilitation, Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Medicine, Tongji University, Shanghai, China
| | - Xiafeng Shen
- Department of Rehabilitation, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai, China
| | - Yu Zhang
- Key Laboratory of Cellular Physiology (Shanxi Medical University), Ministry of Education, and the Department of Physiology, Shanxi Medical University, Taiyuan, Shanxi Province, China
| | - Li Zhang
- Key Laboratory of Central CNS Regeneration (Ministry of Education), Guangdong-Hong Kong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, Guangdong Province, China
| | - Ling Zhang
- Department of Neurology and Neurological Rehabilitation, Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Medicine, Tongji University, Shanghai, China
| |
Collapse
|
5
|
Wen B, Pan Y, Cheng J, Xu L, Xu J. The Role of Neuroinflammation in Complex Regional Pain Syndrome: A Comprehensive Review. J Pain Res 2023; 16:3061-3073. [PMID: 37701560 PMCID: PMC10493102 DOI: 10.2147/jpr.s423733] [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: 06/16/2023] [Accepted: 08/26/2023] [Indexed: 09/14/2023] Open
Abstract
Complex Regional Pain Syndrome (CRPS) is an excess and/or prolonged pain and inflammation condition that follows an injury to a limb. The pathogenesis of CRPS is multifaceted that remains incompletely understood. Neuroinflammation is an inflammatory response in the peripheral and central nervous systems. Dysregulated neuroinflammation plays a crucial role in the initiation and maintenance of pain and nociceptive neuronal sensitization, which may contribute to the transition from acute to chronic pain and the perpetuation of chronic pain in CRPS. The key features of neuroinflammation encompass infiltration and activation of inflammatory cells and the production of inflammatory mediators in both the central and peripheral nervous systems. This article reviews the role of neuroinflammation in the onset and progression of CRPS from six perspectives: neurogenic inflammation, neuropeptides, glial cells, immune cells, cytokines, and keratinocytes. The objective is to provide insights that can inform future research and development of therapeutic targets for CRPS.
Collapse
Affiliation(s)
- Bei Wen
- Department of Anesthesiology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100730, People’s Republic of China
| | - Yinbing Pan
- Department of Anesthesiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, People’s Republic of China
| | - Jianguo Cheng
- Department of Pain Management, Cleveland Clinic, Cleveland, OH, 44195, USA
- Department of Neuroscience, Cleveland Clinic, Cleveland, OH, 44195, USA
| | - Li Xu
- Department of Anesthesiology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100730, People’s Republic of China
| | - Jijun Xu
- Department of Pain Management, Cleveland Clinic, Cleveland, OH, 44195, USA
- Department of Inflammation and Immunity; Cleveland Clinic, Cleveland, OH, 44195, USA
| |
Collapse
|
6
|
Shibata S, Tagashira H, Nemoto T, Kita S, Kita T, Shinoda Y, Akiyoshi K, Yamaura K, Iwamoto T. Perineural treatment with anti-TNF-α antibody ameliorates persistent allodynia and edema in novel mouse models with complex regional pain syndrome. J Pharmacol Sci 2023; 153:1-11. [PMID: 37524448 DOI: 10.1016/j.jphs.2023.06.003] [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: 02/23/2023] [Revised: 05/31/2023] [Accepted: 06/20/2023] [Indexed: 08/02/2023] Open
Abstract
Complex regional pain syndrome (CRPS) is an intractable chronic pain syndrome with various signs and symptoms including allodynia/hyperalgesia, edema, swelling, and skin abnormalities. However, a definitive therapeutic treatment for CRPS has not been established. In CRPS patients, inflammatory cytokines such as TNF-α and IL-1β have been shown to increase in affected areas, suggesting that these molecules may be potential therapeutic targets for CRPS. Here, we first created a novel CRPS mouse model (CRPS-II-like) via sciatic nerve injury and cast immobilization, which was characterized by mechanical allodynia, local edema, and skin abnormalities, to evaluate the pathophysiology and pharmacotherapy of CRPS. When an anti-TNF-α antibody was consecutively administered near the injured sciatic nerve of CRPS model mice, persistent allodynia and CRPS-related signs in the ipsilateral hindpaw were markedly attenuated to control levels. Perineural administration of anti-TNF-α antibody also suppressed the upregulation of inflammatory cytokines as well as the activation of macrophages and Schwann cells in the injured sciatic nerve. These findings indicate that persistent allodynia and CRPS-related signs in CRPS models are primarily associated with TNF-α-mediated immune responses in injured peripheral nerves, suggesting that perineural treatment with anti-TNF-α antibody might be therapeutically useful.
Collapse
Affiliation(s)
- Shiho Shibata
- Department of Pharmacology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan; Department of Anesthesiology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan
| | - Hideaki Tagashira
- Department of Pharmacology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan
| | - Takayuki Nemoto
- Department of Pharmacology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan.
| | - Satomi Kita
- Department of Pharmacology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan; Department of Pharmacology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, Japan
| | - Tomo Kita
- Department of Pharmacology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan
| | - Yasuharu Shinoda
- Department of Pharmacology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan
| | - Kouzaburo Akiyoshi
- Department of Anesthesiology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan
| | - Ken Yamaura
- Department of Anesthesiology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan; Department of Anesthesiology & Critical Care Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Takahiro Iwamoto
- Department of Pharmacology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan.
| |
Collapse
|
7
|
Wu Q, Cui X, Guan LC, Zhang C, Liu J, Ford NC, He S, Chen X, Cao X, Zang L, Guan Y. Chronic pain after spine surgery: Insights into pathogenesis, new treatment, and preventive therapy. J Orthop Translat 2023; 42:147-159. [PMID: 37823035 PMCID: PMC10562770 DOI: 10.1016/j.jot.2023.07.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 07/12/2023] [Accepted: 07/13/2023] [Indexed: 10/13/2023] Open
Abstract
Chronic pain after spine surgery (CPSS) is often characterized by intractable low back pain and/or radiating leg pain, and has been reported in 8-40% of patients that received lumbar spine surgery. We conducted a literature search of PubMed, MEDLINE/OVID with a focus on studies about the etiology and treatments of CPSS and low back pain. Our aim was to provide a narrative review that would help us better understand the pathogenesis and current treatment options for CPSS. This knowledge will aid in the development of optimal strategies for managing postoperative pain symptoms and potentially curing the underlying etiologies. Firstly, we reviewed recent advances in the mechanistic study of CPSS, illustrated both structural (e.g., fibrosis and scaring) and non-structural factors (e.g., inflammation, neuronal sensitization, glial activation, psychological factor) causing CPSS, and highlighted those having not been given sufficient attention as the etiology of CPSS. Secondly, we summarized clinical evidence and therapeutic perspectives of CPSS. We also presented new insights about the treatments and etiology of CPSS, in order to raise awareness of medical staff in the identification and management of this complex painful disease. Finally, we discussed potential new targets for clinical interventions of CPSS and future perspectives of mechanistic and translational research. CPSS patients often have a mixed etiology. By reviewing recent findings, the authors advocate that clinicians shall comprehensively evaluate each case to formulate a patient-specific and multi-modal pain treatment, and importantly, consider an early intraoperative intervention that may decrease the risk or even prevent the onset of CPSS. Translational potential statement CPSS remains difficult to treat. This review broadens our understanding of clinical therapies and underlying mechanisms of CPSS, and provides new insights which will aid in the development of novel mechanism-based therapies for not only managing the established pain symptoms but also preventing the development of CPSS.
Collapse
Affiliation(s)
- Qichao Wu
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD, 21205, USA
- Department of Orthopedics, Beijing Chaoyang Hospital, Capital Medical University, Beijing, 100149, China
| | - Xiang Cui
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD, 21205, USA
| | - Leo C. Guan
- McDonogh School, Owing Mills, Maryland, 21117, USA
| | - Chi Zhang
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD, 21205, USA
| | - Jing Liu
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD, 21205, USA
| | - Neil C. Ford
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD, 21205, USA
| | - Shaoqiu He
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD, 21205, USA
| | - Xueming Chen
- Department of Orthopedics, Beijing Luhe Hospital, Capital Medical University, Beijing, 100149, China
| | - Xu Cao
- Department of Orthopedics, Johns Hopkins University, School of Medicine, Baltimore, MD, 21205, USA
| | - Lei Zang
- Department of Orthopedics, Beijing Chaoyang Hospital, Capital Medical University, Beijing, 100149, China
| | - Yun Guan
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD, 21205, USA
- Department of Neurological Surgery, Johns Hopkins University, School of Medicine, Baltimore, MD, 21205, USA
| |
Collapse
|
8
|
Liu X, Tang SJ. Pathogenic mechanisms of human immunodeficiency virus (HIV)-associated pain. Mol Psychiatry 2023; 28:3613-3624. [PMID: 37857809 DOI: 10.1038/s41380-023-02294-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 09/25/2023] [Accepted: 10/05/2023] [Indexed: 10/21/2023]
Abstract
Chronic pain is a prevalent neurological complication among individuals living with human immunodeficiency virus (PLHIV) in the post-combination antiretroviral therapy (cART) era. These individuals experience malfunction in various cellular and molecular pathways involved in pain transmission and modulation, including the neuropathology of the peripheral sensory neurons and neurodegeneration and neuroinflammation in the spinal dorsal horn. However, the underlying etiologies and mechanisms leading to pain pathogenesis are complex and not fully understood. In this review, we aim to summarize recent progress in this field. Specifically, we will begin by examining neuropathology in the pain pathways identified in PLHIV and discussing potential causes, including those directly related to HIV-1 infection and comorbidities, such as antiretroviral drug use. We will also explore findings from animal models that may provide insights into the molecular and cellular processes contributing to neuropathology and chronic pain associated with HIV infection. Emerging evidence suggests that viral proteins and/or antiretroviral drugs trigger a complex pathological cascade involving neurons, glia, and potentially non-neural cells, and that interactions between these cells play a critical role in the pathogenesis of HIV-associated pain.
Collapse
Affiliation(s)
- Xin Liu
- Stony Brook University Pain and Analgesia Research Center (SPARC), Stony Brook University, Stony Brook, 11794, NY, USA
- Department of Anesthesiology, Renaissance School of Medicine, Stony Brook University, Stony Brook, 11794, NY, USA
| | - Shao-Jun Tang
- Stony Brook University Pain and Analgesia Research Center (SPARC), Stony Brook University, Stony Brook, 11794, NY, USA.
- Department of Anesthesiology, Renaissance School of Medicine, Stony Brook University, Stony Brook, 11794, NY, USA.
| |
Collapse
|
9
|
De Schoenmacker I, Mollo A, Scheuren PS, Sirucek L, Brunner F, Schweinhardt P, Curt A, Rosner J, Hubli M. Central sensitization in CRPS patients with widespread pain: a cross-sectional study. PAIN MEDICINE (MALDEN, MASS.) 2023; 24:974-984. [PMID: 36946277 PMCID: PMC10391588 DOI: 10.1093/pm/pnad040] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 03/08/2023] [Accepted: 03/20/2023] [Indexed: 03/23/2023]
Abstract
OBJECTIVE Widespread pain hypersensitivity and enhanced temporal summation of pain (TSP) are commonly reported in patients with complex regional pain syndrome (CRPS) and discussed as proxies for central sensitization. This study aimed to directly relate such signs of neuronal hyperexcitability to the pain phenotype of CRPS patients. METHODS Twenty-one CRPS patients and 20 healthy controls (HC) were recruited. The pain phenotype including spatial pain extent (assessed in % body surface) and intensity were assessed and related to widespread pain hypersensitivity, TSP, and psychological factors. Quantitative sensory testing (QST) was performed in the affected, the contralateral and a remote (control) area. RESULTS CRPS patients showed decreased pressure pain thresholds in all tested areas (affected: t(34) = 4.98, P < .001, contralateral: t(35) = 3.19, P = .005, control: t(31) = 2.65, P = .012). Additionally, patients showed increased TSP in the affected area (F(3,111) = 4.57, P = .009) compared to HC. TSP was even more enhanced in patients with a high compared to a low spatial pain extent (F(3,51) = 5.67, P = .008), suggesting pronounced spinal sensitization in patients with extended pain patterns. Furthermore, the spatial pain extent positively correlated with the Bath Body Perception Disturbance Scale (ρ = 0.491; P = .048). CONCLUSIONS Overall, we provide evidence that the pain phenotype in CRPS, that is, spatial pain extent, might be related to sensitization mechanism within the central nociceptive system. This study points towards central neuronal excitability as a potential therapeutic target in patients with more widespread CRPS.
Collapse
Affiliation(s)
- Iara De Schoenmacker
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, 8008 Zurich, Switzerland
| | - Anna Mollo
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, 8008 Zurich, Switzerland
| | - Paulina Simonne Scheuren
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, 8008 Zurich, Switzerland
| | - Laura Sirucek
- Integrative Spinal Research, Department of Chiropractic Medicine, University Hospital Balgrist, University of Zurich, 8008 Zurich, Switzerland
| | - Florian Brunner
- Physical Medicine and Rheumatology, Balgrist University Hospital, 8008 Zurich, Switzerland
| | - Petra Schweinhardt
- Integrative Spinal Research, Department of Chiropractic Medicine, University Hospital Balgrist, University of Zurich, 8008 Zurich, Switzerland
- Alan Edward Center for Research on Pain, McGill University, Montreal, Quebec, Canada
| | - Armin Curt
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, 8008 Zurich, Switzerland
| | - Jan Rosner
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, 8008 Zurich, Switzerland
- Department of Neurology, University Hospital Bern, Inselspital, University of Bern, Bern, Switzerland
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Michèle Hubli
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, 8008 Zurich, Switzerland
| |
Collapse
|
10
|
McGinnis A, Ji RR. The Similar and Distinct Roles of Satellite Glial Cells and Spinal Astrocytes in Neuropathic Pain. Cells 2023; 12:965. [PMID: 36980304 PMCID: PMC10047571 DOI: 10.3390/cells12060965] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 03/19/2023] [Accepted: 03/20/2023] [Indexed: 03/30/2023] Open
Abstract
Preclinical studies have identified glial cells as pivotal players in the genesis and maintenance of neuropathic pain after nerve injury associated with diabetes, chemotherapy, major surgeries, and virus infections. Satellite glial cells (SGCs) in the dorsal root and trigeminal ganglia of the peripheral nervous system (PNS) and astrocytes in the central nervous system (CNS) express similar molecular markers and are protective under physiological conditions. They also serve similar functions in the genesis and maintenance of neuropathic pain, downregulating some of their homeostatic functions and driving pro-inflammatory neuro-glial interactions in the PNS and CNS, i.e., "gliopathy". However, the role of SGCs in neuropathic pain is not simply as "peripheral astrocytes". We delineate how these peripheral and central glia participate in neuropathic pain by producing different mediators, engaging different parts of neurons, and becoming active at different stages following nerve injury. Finally, we highlight the recent findings that SGCs are enriched with proteins related to fatty acid metabolism and signaling such as Apo-E, FABP7, and LPAR1. Targeting SGCs and astrocytes may lead to novel therapeutics for the treatment of neuropathic pain.
Collapse
Affiliation(s)
- Aidan McGinnis
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Ru-Rong Ji
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| |
Collapse
|
11
|
Su PYP, Zhang L, He L, Zhao N, Guan Z. The Role of Neuro-Immune Interactions in Chronic Pain: Implications for Clinical Practice. J Pain Res 2022; 15:2223-2248. [PMID: 35957964 PMCID: PMC9359791 DOI: 10.2147/jpr.s246883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 07/19/2022] [Indexed: 11/23/2022] Open
Affiliation(s)
- Po-Yi Paul Su
- Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, CA, USA
| | - Lingyi Zhang
- Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, CA, USA
- Department of Anesthesiology, the First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, People’s Republic of China
| | - Liangliang He
- Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, CA, USA
- Department of Pain Management, Xuanwu Hospital, Capital Medical University, Beijing, People’s Republic of China
| | - Na Zhao
- Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, CA, USA
| | - Zhonghui Guan
- Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, CA, USA
- Correspondence: Zhonghui Guan, Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, CA, USA, Tel +415.885.7246, Fax +415.885.7575, Email
| |
Collapse
|
12
|
Lee B, Di Pietro F, Henderson LA, Austin PJ. Altered basal ganglia infraslow oscillation and resting functional connectivity in complex regional pain syndrome. J Neurosci Res 2022; 100:1487-1505. [PMID: 35441738 PMCID: PMC9543905 DOI: 10.1002/jnr.25057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 04/03/2022] [Accepted: 04/05/2022] [Indexed: 11/06/2022]
Abstract
Complex regional pain syndrome (CRPS) is a painful condition commonly accompanied by movement disturbances and often affects the upper limbs. The basal ganglia motor loop is central to movement, however, non-motor basal ganglia loops are involved in pain, sensory integration, visual processing, cognition, and emotion. Systematic evaluation of each basal ganglia functional loop and its relation to motor and non-motor disturbances in CRPS has not been investigated. We recruited 15 upper limb CRPS and 45 matched healthy control subjects. Using functional magnetic resonance imaging, infraslow oscillations (ISO) and resting-state functional connectivity in motor and non-motor basal ganglia loops were investigated using putamen and caudate seeds. Compared to controls, CRPS subjects displayed increased ISO power in the putamen contralateral to the CRPS affected limb, specifically, in contralateral putamen areas representing the supplementary motor area hand, motor hand, and motor tongue. Furthermore, compared to controls, CRPS subjects displayed increased resting connectivity between these putaminal areas as well as from the caudate body to cortical areas such as the primary motor cortex, supplementary and cingulate motor areas, parietal association areas, and the orbitofrontal cortex. These findings demonstrate changes in basal ganglia loop function in CRPS subjects and may underpin motor disturbances of CRPS.
Collapse
Affiliation(s)
- Barbara Lee
- School of Medical Sciences and Brain and Mind Centre, University of Sydney, Camperdown, New South Wales, Australia
| | - Flavia Di Pietro
- Curtin Medical School, Faculty of Health Sciences, Curtin University, Bentley, Western Australia, Australia.,Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, Australia
| | - Luke A Henderson
- School of Medical Sciences and Brain and Mind Centre, University of Sydney, Camperdown, New South Wales, Australia
| | - Paul J Austin
- School of Medical Sciences and Brain and Mind Centre, University of Sydney, Camperdown, New South Wales, Australia
| |
Collapse
|
13
|
Choi S, Kim K, Kwon M, Bai SJ, Cha M, Lee BH. Modulation of Neuropathic Pain by Glial Regulation in the Insular Cortex of Rats. Front Mol Neurosci 2022; 15:815945. [PMID: 35493331 PMCID: PMC9043281 DOI: 10.3389/fnmol.2022.815945] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 02/22/2022] [Indexed: 12/12/2022] Open
Abstract
The insular cortex (IC) is known to process pain information. However, analgesic effects of glial inhibition in the IC have not yet been explored. The aim of this study was to investigate pain alleviation effects after neuroglia inhibition in the IC during the early or late phase of pain development. The effects of glial inhibitors in early or late phase inhibition in neuropathic pain were characterized in astrocytes and microglia expressions in the IC of an animal model of neuropathic pain. Changes in withdrawal responses during different stages of inhibition were compared, and morphological changes in glial cells with purinergic receptor expressions were analyzed. Inhibition of glial cells had an analgesic effect that persisted even after drug withdrawal. Both GFAP and CD11b/c expressions were decreased after injection of glial inhibitors. Morphological alterations of astrocytes and microglia were observed with expression changes of purinergic receptors. These findings indicate that inhibition of neuroglia activity in the IC alleviates chronic pain, and that purinergic receptors in glial cells are closely related to chronic pain development.
Collapse
Affiliation(s)
- Songyeon Choi
- Department of Physiology, Yonsei University College of Medicine, Seoul, South Korea
- Department of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul, South Korea
| | - Kyeongmin Kim
- Department of Physiology, Yonsei University College of Medicine, Seoul, South Korea
- Department of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul, South Korea
| | - Minjee Kwon
- Department of Nursing, Kyungil University, Gyeongsan, South Korea
| | - Sun Joon Bai
- Department of Anesthesiology and Pain Medicine, Yonsei University College of Medicine, Seoul, South Korea
| | - Myeounghoon Cha
- Department of Physiology, Yonsei University College of Medicine, Seoul, South Korea
- *Correspondence: Myeounghoon Cha,
| | - Bae Hwan Lee
- Department of Physiology, Yonsei University College of Medicine, Seoul, South Korea
- Department of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul, South Korea
- Bae Hwan Lee,
| |
Collapse
|
14
|
Okumo T, Takayama Y, Maruyama K, Kato M, Sunagawa M. Senso-Immunologic Prospects for Complex Regional Pain Syndrome Treatment. Front Immunol 2022; 12:786511. [PMID: 35069559 PMCID: PMC8767061 DOI: 10.3389/fimmu.2021.786511] [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: 09/30/2021] [Accepted: 12/13/2021] [Indexed: 12/14/2022] Open
Abstract
Complex regional pain syndrome (CRPS) is a chronic pain syndrome that occurs in tissue injuries as the result of surgery, trauma, or ischemia. The clinical features of this severely painful condition include redness and swelling of the affected skin. Intriguingly, it was recently suggested that transient receptor potential ankyrin 1 (TRPA1) is involved in chronic post-ischemia pain, a CRPS model. TRPA1 is a non-selective cation channel expressed in calcitonin gene-related peptide (CGRP)-positive primary nociceptors that becomes highly activated in ischemic conditions, leading to the generation of pain. In this review, we summarize the history of TRPA1 and its involvement in pain sensation, inflammation, and CRPS. Furthermore, bone atrophy is also thought to be a characteristic clinical sign of CRPS. The altered bone microstructure of CRPS patients is thought to be caused by aggravated bone resorption via enhanced osteoclast differentiation and activation. Although TRPA1 could be a target for pain treatment in CRPS patients, we also discuss the paradoxical situation in this review. Nociceptor activation decreases the risk of bone destruction via CGRP secretion from free nerve endings. Thus, TRPA1 inhibition could cause severe bone atrophy. However, the suitable therapeutic strategy is controversial because the pathologic mechanisms of bone atrophy in CRPS are unclear. Therefore, we propose focusing on the remission of abnormal bone turnover observed in CRPS using a recently developed concept: senso-immunology.
Collapse
Affiliation(s)
- Takayuki Okumo
- Department of Physiology, Showa University School of Medicine, Shinagawa, Japan
| | - Yasunori Takayama
- Department of Physiology, Showa University School of Medicine, Shinagawa, Japan
| | - Kenta Maruyama
- Department of Physiology, Showa University School of Medicine, Shinagawa, Japan.,Division of Cell Signaling, National Institute for Physiological Sciences, Natural Institutes for Natural Sciences, Okazaki, Japan
| | - Mami Kato
- Department of Physiology, Showa University School of Medicine, Shinagawa, Japan.,Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Masataka Sunagawa
- Department of Physiology, Showa University School of Medicine, Shinagawa, Japan
| |
Collapse
|
15
|
Mechanistic Insight into the Effects of Curcumin on Neuroinflammation-Driven Chronic Pain. Pharmaceuticals (Basel) 2021; 14:ph14080777. [PMID: 34451874 PMCID: PMC8397941 DOI: 10.3390/ph14080777] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 08/03/2021] [Accepted: 08/04/2021] [Indexed: 12/22/2022] Open
Abstract
Chronic pain is a persistent and unremitting condition that has immense effects on patients' quality of life. Studies have shown that neuroinflammation is associated with the induction and progression of chronic pain. The activation of microglia and astrocytes is the major hallmark of spinal neuroinflammation leading to neuronal excitability in the projection neurons. Excessive activation of microglia and astrocytes is one of the major contributing factors to the exacerbation of pain. However, the current chronic pain treatments, mainly by targeting the neuronal cells, remain ineffective and unable to meet the patients' needs. Curcumin, a natural plant product found in the Curcuma genus, improves chronic pain by diminishing the release of inflammatory mediators from the spinal glia. This review details the role of curcumin in microglia and astrocytes both in vitro and in vivo and how it improves pain. We also describe the mechanism of curcumin by highlighting the major glia-mediated cascades in pain. Moreover, the role of curcumin on inflammasome and epigenetic regulation is discussed. Furthermore, we discuss the strategies used to improve the efficacy of curcumin. This review illustrates that curcumin modulating microglia and astrocytes could assure the treatment of chronic pain by suppressing spinal neuroinflammation.
Collapse
|
16
|
Mills EP, Keay KA, Henderson LA. Brainstem Pain-Modulation Circuitry and Its Plasticity in Neuropathic Pain: Insights From Human Brain Imaging Investigations. FRONTIERS IN PAIN RESEARCH 2021; 2:705345. [PMID: 35295481 PMCID: PMC8915745 DOI: 10.3389/fpain.2021.705345] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 06/23/2021] [Indexed: 11/17/2022] Open
Abstract
Acute pain serves as a protective mechanism that alerts us to potential tissue damage and drives a behavioural response that removes us from danger. The neural circuitry critical for mounting this behavioural response is situated within the brainstem and is also crucial for producing analgesic and hyperalgesic responses. In particular, the periaqueductal grey, rostral ventromedial medulla, locus coeruleus and subnucleus reticularis dorsalis are important structures that directly or indirectly modulate nociceptive transmission at the primary nociceptive synapse. Substantial evidence from experimental animal studies suggests that plasticity within this system contributes to the initiation and/or maintenance of chronic neuropathic pain, and may even predispose individuals to developing chronic pain. Indeed, overwhelming evidence indicates that plasticity within this circuitry favours pro-nociception at the primary synapse in neuropathic pain conditions, a process that ultimately contributes to a hyperalgesic state. Although experimental animal investigations have been crucial in our understanding of the anatomy and function of the brainstem pain-modulation circuitry, it is vital to understand this system in acute and chronic pain states in humans so that more effective treatments can be developed. Recent functional MRI studies have identified a key role of this system during various analgesic and hyperalgesic responses including placebo analgesia, offset analgesia, attentional analgesia, conditioned pain modulation, central sensitisation and temporal summation. Moreover, recent MRI investigations have begun to explore brainstem pain-modulation circuitry plasticity in chronic neuropathic pain conditions and have identified altered grey matter volumes and functioning throughout the circuitry. Considering the findings from animal investigations, it is likely that these changes reflect a shift towards pro-nociception that ultimately contributes to the maintenance of neuropathic pain. The purpose of this review is to provide an overview of the human brain imaging investigations that have improved our understanding of the pain-modulation system in acute pain states and in neuropathic conditions. Our interpretation of the findings from these studies is often guided by the existing body of experimental animal literature, in addition to evidence from psychophysical investigations. Overall, understanding the plasticity of this system in human neuropathic pain conditions alongside the existing experimental animal literature will ultimately improve treatment options.
Collapse
|
17
|
Abstract
BACKGROUND Pain and depression have a high impact on caring for the people who need palliative care, but both of these are neglected compared with the approach for other symptoms encountered by these patients. AREAS OF UNCERTAINTY There are few studies in humans that support the existence of common neural circuits between depression and pain that also explore the use of drugs with effects in both conditions. More knowledge is needed about the relationship of these clinical entities that will lead to the optimization of the treatment and improvement of quality of life. DATA SOURCES We conducted a search in PubMed to identify relevant articles and reviews that have been published in the last 5 years, concerning the topic of common pathways between depression and pain (2014-April 2019). THERAPEUTIC ADVANCES The connections between the 2 clinical entities start at the level of the cortical regions. The hippocampus is the main site of neural changes, modification of the immune system, neuromodulators, neurotransmitters, and signaling pathways implicated in both conditions. Increased levels of peripheral proinflammatory cytokines and neuroinflammatory changes are related to the physiopathology of these entities. Inflammation links depression and pain by altering neural circuits and changes in their common cortical regions. Antidepressants are used to treat depression and chronic, pain but more experimental studies are needed to determine which antidepressant drugs are the most effective in treating the 2 entities. CONCLUSIONS Pharmacological and nonpharmacological interventions targeting cortical changes in pain and depression are promising, but more clinical studies are needed to validate their usefulness.
Collapse
|
18
|
Role of microglia and P2X4 receptors in chronic pain. Pain Rep 2021; 6:e864. [PMID: 33981920 PMCID: PMC8108579 DOI: 10.1097/pr9.0000000000000864] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/01/2020] [Accepted: 09/08/2020] [Indexed: 12/15/2022] Open
Abstract
This study summarizes current understanding of the role of microglia and P2X4 receptor in chronic pain including neuropathic pain and of their therapeutic potential. Pain plays an indispensable role as an alarm system to protect us from dangers or injuries. However, neuropathic pain, a debilitating pain condition caused by damage to the nervous system, persists for a long period even in the absence of dangerous stimuli or after injuries have healed. In this condition, pain becomes a disease itself rather than the alarm system and is often resistant to currently available medications. A growing body of evidence indicates that microglia, a type of macrophages residing in the central nervous system, play a crucial role in the pathogenesis of neuropathic pain. Whenever microglia in the spinal cord detect a damaging signal within the nervous system, they become activated and cause diverse alterations that change neural excitability, leading to the development of neuropathic pain. For over a decade, several lines of molecular and cellular mechanisms that define microglial activation and subsequently altered pain transmission have been proposed. In particular, P2X4 receptors (a subtype of purinergic receptors) expressed by microglia have been investigated as an essential molecule for neuropathic pain. In this review article, we describe our understanding of the mechanisms by which activated microglia cause neuropathic pain through P2X4 receptors, their involvement in several pathological contexts, and recent efforts to develop new drugs targeting microglia and P2X4 receptors.
Collapse
|
19
|
Midavaine É, Côté J, Marchand S, Sarret P. Glial and neuroimmune cell choreography in sexually dimorphic pain signaling. Neurosci Biobehav Rev 2021; 125:168-192. [PMID: 33582232 DOI: 10.1016/j.neubiorev.2021.01.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 11/03/2020] [Accepted: 01/25/2021] [Indexed: 12/17/2022]
Abstract
Chronic pain is a major global health issue that affects all populations regardless of sex, age, ethnicity/race, or country of origin, leading to persistent physical and emotional distress and to the loss of patients' autonomy and quality of life. Despite tremendous efforts in the elucidation of the mechanisms contributing to the pathogenesis of chronic pain, the identification of new potential pain targets, and the development of novel analgesics, the pharmacological treatment options available for pain management remain limited, and most novel pain medications have failed to achieve advanced clinical development, leaving many patients with unbearable and undermanaged pain. Sex-specific susceptibility to chronic pain conditions as well as sex differences in pain sensitivity, pain tolerance and analgesic efficacy are increasingly recognized in the literature and have thus prompted scientists to seek mechanistic explanations. Hence, recent findings have highlighted that the signaling mechanisms underlying pain hypersensitivity are sexually dimorphic, which sheds light on the importance of conducting preclinical and clinical pain research on both sexes and of developing sex-specific pain medications. This review thus focuses on the clinical and preclinical evidence supporting the existence of sex differences in pain neurobiology. Attention is drawn to the sexually dimorphic role of glial and immune cells, which are both recognized as key players in neuroglial maladaptive plasticity at the origin of the transition from acute pain to chronic pathological pain. Growing evidence notably attributes to microglial cells a pivotal role in the sexually dimorphic pain phenotype and in the sexually dimorphic analgesic efficacy of opioids. This review also summarizes the recent advances in understanding the pathobiology underpinning the development of pain hypersensitivity in both males and females in different types of pain conditions, with particular emphasis on the mechanistic signaling pathways driving sexually dimorphic pain responses.
Collapse
Affiliation(s)
- Élora Midavaine
- Department of Pharmacology-Physiology, Institut de pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada; Centre de recherche du Centre hospitalier universitaire de Sherbrooke, CIUSSS de l'Estrie - CHUS, Sherbrooke, Québec, Canada.
| | - Jérôme Côté
- Department of Pharmacology-Physiology, Institut de pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada; Centre de recherche du Centre hospitalier universitaire de Sherbrooke, CIUSSS de l'Estrie - CHUS, Sherbrooke, Québec, Canada
| | - Serge Marchand
- Department of Pharmacology-Physiology, Institut de pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada; Centre de recherche du Centre hospitalier universitaire de Sherbrooke, CIUSSS de l'Estrie - CHUS, Sherbrooke, Québec, Canada
| | - Philippe Sarret
- Department of Pharmacology-Physiology, Institut de pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada; Centre de recherche du Centre hospitalier universitaire de Sherbrooke, CIUSSS de l'Estrie - CHUS, Sherbrooke, Québec, Canada.
| |
Collapse
|
20
|
Of mice, microglia, and (wo)men: a case series and mechanistic investigation of hydroxychloroquine for complex regional pain syndrome. Pain Rep 2021; 5:e841. [PMID: 33490839 PMCID: PMC7808678 DOI: 10.1097/pr9.0000000000000841] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 06/19/2020] [Accepted: 07/02/2020] [Indexed: 12/27/2022] Open
Abstract
Introduction Complex regional pain syndrome (CRPS) is a condition that occurs after minor trauma characterized by sensory, trophic, and motor changes. Although preclinical studies have demonstrated that CRPS may be driven in part by autoinflammation, clinical use of immune-modulating drugs in CRPS is limited. Hydroxychloroquine (HCQ) is a disease-modifying antirheumatic drug used to treat malaria and autoimmune disorders that may provide benefit in CRPS. Objectives To describe the use of HCQ in patients with refractory CRPS and investigate possible mechanisms of benefit in a mouse model of CRPS. Methods We initiated HCQ therapy in 7 female patients with refractory CRPS undergoing treatment at the Stanford Pain Management Center. We subsequently undertook studies in the mouse tibial fracture-casting model of CRPS to identify mechanisms underlying symptom reduction. We evaluated behavior using mechanical allodynia and spinal cord autoinflammation by immunohistochemistry and enzyme-linked immunosorbent assay. Results We treated 7 female patients with chronic, refractory CRPS with HCQ 200 mg twice daily for 2 months, followed by 200 mg daily thereafter. Two patients stopped HCQ secondary to lack of response or side effects. Overall, HCQ significantly improved average numerical rating scale pain from 6.8 ± 1.1 before HCQ to 3.8 ± 1.9 after HCQ treatment. In the tibial fracture-casting mouse model of CRPS, we observed reductions in allodynia, paw edema, and warmth following daily HCQ treatment starting at 3 weeks after injury. Spinal cord dorsal horn microglial activation and cytokine levels were also reduced by HCQ treatment. Conclusion Together, these preclinical and clinical results suggest that HCQ may benefit patients with CRPS at least in part by modulating autoinflammation and support further investigation into the use of HCQ for CRPS.
Collapse
|
21
|
The Neuroimmunology of Chronic Pain: From Rodents to Humans. J Neurosci 2020; 41:855-865. [PMID: 33239404 DOI: 10.1523/jneurosci.1650-20.2020] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/29/2020] [Accepted: 10/04/2020] [Indexed: 12/11/2022] Open
Abstract
Chronic pain, encompassing conditions, such as low back pain, arthritis, persistent post-surgical pain, fibromyalgia, and neuropathic pain disorders, is highly prevalent but remains poorly treated. The vast majority of therapeutics are directed solely at neurons, despite the fact that signaling between immune cells, glia, and neurons is now recognized as indispensable for the initiation and maintenance of chronic pain. This review highlights recent advances in understanding fundamental neuroimmune signaling mechanisms and novel therapeutic targets in rodent models of chronic pain. We further discuss new technological developments to study, diagnose, and quantify neuroimmune contributions to chronic pain in patient populations.
Collapse
|
22
|
An Investigation into Proteomic Constituents of Cerebrospinal Fluid in Patients with Chronic Peripheral Neuropathic Pain Medicated with Opioids- a Pilot Study. J Neuroimmune Pharmacol 2020; 16:634-650. [PMID: 33219474 DOI: 10.1007/s11481-020-09970-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 10/30/2020] [Indexed: 12/25/2022]
Abstract
The pharmacodynamics of opioids for chronic peripheral neuropathic pain are complex and likely extend beyond classical opioid receptor theory. Preclinical evidence of opioid modulation of central immune signalling has not been identified in vivo in humans. Examining the cerebrospinal fluid (CSF) of patients medicated with opioids is required to identify potential pharmacodynamic mechanisms. We compared CSF samples of chronic peripheral neuropathic pain patients receiving opioids (n = 7) versus chronic peripheral neuropathic pain patients not taking opioids (control group, n = 13). Baseline pain scores with demographics were recorded. Proteome analysis was performed using mass spectrometry and secreted neuropeptides were measured by enzyme-linked immunosorbent assay. Based on Gene Ontology analysis, proteins involved in the positive regulation of nervous system development and myeloid leukocyte activation were increased in patients taking opioids versus the control group. The largest decrease in protein expression in patients taking opioids were related to neutrophil mediated immunity. In addition, notably higher expression levels of neural proteins (85%) and receptors (80%) were detected in the opioid group compared to the control group. This study suggests modulation of CNS homeostasis, possibly attributable to opioids, thus highlighting potential mechanisms for the pharmacodynamics of opioids. We also provide new insights into the immunomodulatory functions of opioids in vivo.
Collapse
|
23
|
Inoue K, Tsuda M. Nociceptive signaling mediated by P2X3, P2X4 and P2X7 receptors. Biochem Pharmacol 2020; 187:114309. [PMID: 33130129 DOI: 10.1016/j.bcp.2020.114309] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/22/2020] [Accepted: 10/27/2020] [Indexed: 12/18/2022]
Abstract
Chronic pain is a debilitating condition that often occurs following peripheral tissue inflammation and nerve injury. This pain, especially neuropathic pain, is a significant clinical problem because of the ineffectiveness of clinically available drugs. Since Burnstock proposed new roles of nucleotides as neurotransmitters, the roles of extracellular ATP and P2 receptors (P2Rs) in pain signaling have been extensively studied, and ATP-P2R signaling has subsequently received much attention as it can provide clues toward elucidating the mechanisms underlying chronic pain and serve as a potential therapeutic target. This review summarizes the literature regarding the role of ATP signaling via P2X3Rs (as well as P2X2/3Rs) in primary afferent neurons and via P2X4Rs and P2X7Rs in spinal cord microglia in chronic pain, and discusses their respective therapeutic potentials.
Collapse
Affiliation(s)
- Kazuhide Inoue
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi, Fukuoka 812-8582, Japan
| | - Makoto Tsuda
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi, Fukuoka 812-8582, Japan; Department of Life Innovation, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi, Fukuoka 812-8582, Japan
| |
Collapse
|
24
|
Cook A, Ghanavatian S, Jowza M. Spontaneous Spread of Limb Complex Regional Pain Syndrome to the Ipsilateral Face With Ultimate Corneal Abrasion: A Case Report. A A Pract 2020; 14:e01301. [DOI: 10.1213/xaa.0000000000001301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
25
|
Cheong Y, Kim M, Kim N, Hwang B. Effect of two-week continuous epidural administration of 2% lidocaine on mechanical allodynia induced by spinal nerve ligation in rats. Anesth Pain Med (Seoul) 2020; 15:334-343. [PMID: 33329833 PMCID: PMC7713833 DOI: 10.17085/apm.20033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 06/30/2020] [Accepted: 06/30/2020] [Indexed: 11/17/2022] Open
Abstract
Background Lidocaine is an effective against certain types of neuropathic pain. This study aimed to investigate whether timing of initiating continuous epidural infusion of lidocaine affected the glial activation and development of neuropathic pain induced by L5/6 spinal nerve ligation (SNL) in rats. Methods Following L5/6 SNL, rats were epidurally infused 2% lidocaine (drug infusion initiated on days 1, and 7 post SNL model establishment) or saline (saline infusion initiated on day 1 post SNL model establishment) continuously for 14 days. Mechanical allodynia of the hind paw to von Frey filament stimuli was determined prior to surgery, postoperative day 3, and once weekly after SNL model establishment. At 7 days after the infusion of saline or lidocaine ended, spinal activation of proinflammatory cytokines and astrocytes was evaluated immunohistochemically, using antibodies to interleukin-6 (IL-6) and glial fibrillary acidic protein (GFAP). Results Continuous epidural administration of 2% lidocaine for 14 days increased the mechanical withdrawal threshold regardless of the difference in timing of initiating lidocaine administration. Epidurally infusing 2% lidocaine inhibited nerve ligation-induced IL-6 and GFAP activation. In the 2% lidocaine infusion group, rats maintained the increased mechanical withdrawal threshold even at 7 days after the discontinuation of 2% lidocaine infusion. Conclusions Continuous epidural administration of 2% lidocaine inhibited the development of SNL-induced mechanical allodynia and suppressed IL-6 and GFAP activation regardless of the difference in timing of initiating lidocaine administration.
Collapse
Affiliation(s)
- Yuseon Cheong
- Department of Anesthesiology and Pain Medicine, Kangwon National University Hospital, Kangwon National University School of Medicine, Chuncheon, Korea
| | - Minsoo Kim
- Department of Anesthesiology and Pain Medicine, Kangwon National University Hospital, Kangwon National University School of Medicine, Chuncheon, Korea
| | - Namyoong Kim
- Department of Anesthesiology and Pain Medicine, Kangwon National University Hospital, Kangwon National University School of Medicine, Chuncheon, Korea
| | - Byeongmun Hwang
- Department of Anesthesiology and Pain Medicine, Kangwon National University Hospital, Kangwon National University School of Medicine, Chuncheon, Korea
| |
Collapse
|
26
|
Longitudinal translocator protein-18 kDa-positron emission tomography imaging of peripheral and central myeloid cells in a mouse model of complex regional pain syndrome. Pain 2020; 160:2136-2148. [PMID: 31095093 PMCID: PMC6527343 DOI: 10.1097/j.pain.0000000000001607] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Supplemental Digital Content is Available in the Text. Longitudinal positron emission tomography of translocator protein-18 kDa revealed early central, and persistent peripheral, myeloid activation in a mouse tibial fracture model of complex regional pain syndrome. Complex regional pain syndrome (CRPS) is a severely disabling disease characterized by pain, temperature changes, motor dysfunction, and edema that most often occurs as an atypical response to a minor surgery or fracture. Inflammation involving activation and recruitment of innate immune cells, including both peripheral and central myeloid cells (ie, macrophages and microglia, respectively), is a key feature of CRPS. However, the exact role and time course of these cellular processes relative to the known acute and chronic phases of the disease are not fully understood. Positron emission tomography (PET) of translocator protein-18 kDa (TSPO) is a method for noninvasively tracking these activated innate immune cells. Here, we reveal the temporal dynamics of peripheral and central inflammatory responses over 20 weeks in a tibial fracture/casting mouse model of CRPS through longitudinal TSPO-PET using [18F]GE-180. Positron emission tomography tracer uptake quantification in the tibia revealed increased peripheral inflammation as early as 2 days after fracture and lasting 7 weeks. Centralized inflammation was detected in the spinal cord and brain of fractured mice at 7 and 21 days after injury. Spinal cord tissue immunofluorescent staining revealed TSPO expression in microglia (CD11b+) at 7 days but was restricted mainly to endothelial cells (PECAM1+) at baseline and 7 weeks. Our data suggest early and persistent peripheral myeloid cell activation and transient central microglial activation are limited to the acute phase of CRPS. Moreover, we show that TSPO-PET can be used to noninvasively monitor the spatiotemporal dynamics of myeloid cell activation in CRPS progression with potential to inform disease phase–specific therapeutics.
Collapse
|
27
|
Di Pietro F, Lee B, Henderson LA. Altered resting activity patterns and connectivity in individuals with complex regional pain syndrome. Hum Brain Mapp 2020; 41:3781-3793. [PMID: 32510695 PMCID: PMC7416050 DOI: 10.1002/hbm.25087] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 05/20/2020] [Accepted: 05/20/2020] [Indexed: 12/20/2022] Open
Abstract
Complex regional pain syndrome (CRPS) is a chronic neuropathic pain disorder that typically occurs in the limbs, usually the upper limb. CRPS usually develops from a peripheral event but its maintenance relies on changes within the central nervous system. While functional abnormalities in the thalamus and primary somatosensory cortex (S1) of the brain are some of the most consistently reported brain findings in CRPS, the mechanisms are yet to be explored in full, not least of all how these two regions interact and how they might relate to clinical deficits, such as the commonly reported poor tactile acuity in this condition. This study recruited 15 upper‐limb CRPS subjects and 30 healthy controls and used functional magnetic resonance imaging (fMRI) to investigate infra‐slow oscillations (ISOs) in critical pain regions of the brain in CRPS. As hypothesised, we found CRPS was associated with increases in resting signal intensity ISOs (0.03–0.06 Hz) in the thalamus contralateral to the painful limb in CRPS subjects. Interestingly, there was no such difference between groups in S1, however CRPS subjects displayed stronger thalamo‐S1 functional connectivity than controls, and this was related to pain. As predicted, CRPS subjects displayed poor tactile acuity on the painful limb which, interestingly, was also related to thalamo‐S1 functional connectivity strength. Our findings provide novel evidence of altered patterns of resting activity and connectivity in CRPS which may underlie altered thalamocortical loop dynamics and the constant perception of pain.
Collapse
Affiliation(s)
- Flavia Di Pietro
- Department of Anatomy and Histology, Brain and Mind Centre, University of Sydney, Sydney, Australia.,School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin University, Perth, Australia
| | - Barbara Lee
- Department of Anatomy and Histology, Brain and Mind Centre, University of Sydney, Sydney, Australia
| | - Luke A Henderson
- Department of Anatomy and Histology, Brain and Mind Centre, University of Sydney, Sydney, Australia
| |
Collapse
|
28
|
Dedek A, Xu J, Kandegedara CM, Lorenzo LÉ, Godin AG, De Koninck Y, Lombroso PJ, Tsai EC, Hildebrand ME. Loss of STEP61 couples disinhibition to N-methyl-d-aspartate receptor potentiation in rodent and human spinal pain processing. Brain 2020; 142:1535-1546. [PMID: 31135041 PMCID: PMC6536915 DOI: 10.1093/brain/awz105] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 02/04/2019] [Accepted: 02/25/2019] [Indexed: 12/13/2022] Open
Abstract
Dysregulated excitability within the spinal dorsal horn is a critical mediator of chronic pain. In the rodent nerve injury model of neuropathic pain, BDNF-mediated loss of inhibition (disinhibition) gates the potentiation of excitatory GluN2B N-methyl-d-aspartate receptor (NMDAR) responses at lamina I dorsal horn synapses. However, the centrality of this mechanism across pain states and species, as well as the molecular linker involved, remain unknown. Here, we show that KCC2-dependent disinhibition is coupled to increased GluN2B-mediated synaptic NMDAR responses in a rodent model of inflammatory pain, with an associated downregulation of the tyrosine phosphatase STEP61. The decreased activity of STEP61 is both necessary and sufficient to prime subsequent phosphorylation and potentiation of GluN2B NMDAR by BDNF at lamina I synapses. Blocking disinhibition reversed the downregulation of STEP61 as well as inflammation-mediated behavioural hypersensitivity. For the first time, we characterize GluN2B-mediated NMDAR responses at human lamina I synapses and show that a human ex vivo BDNF model of pathological pain processing downregulates KCC2 and STEP61 and upregulates phosphorylated GluN2B at dorsal horn synapses. Our results demonstrate that STEP61 is the molecular brake that is lost following KCC2-dependent disinhibition and that the decrease in STEP61 activity drives the potentiation of excitatory GluN2B NMDAR responses in rodent and human models of pathological pain. The ex vivo human BDNF model may thus form a translational bridge between rodents and humans for identification and validation of novel molecular pain targets.
Collapse
Affiliation(s)
- Annemarie Dedek
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada.,Neuroscience Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Jian Xu
- Child Study Center, Yale University School of Medicine, New Haven, CT, USA
| | - Chaya M Kandegedara
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada.,Neuroscience Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | | | - Antoine G Godin
- CERVO Brain Research Centre, Quebec Mental Health Institute, Quebec, QC, Canada.,Department of Psychiatry and Neuroscience, Université Laval, Quebec, QC, Canada
| | - Yves De Koninck
- CERVO Brain Research Centre, Quebec Mental Health Institute, Quebec, QC, Canada.,Department of Psychiatry and Neuroscience, Université Laval, Quebec, QC, Canada.,Graduate Program in Neurobiology, Université Laval, Quebec, QC, Canada
| | - Paul J Lombroso
- Child Study Center, Yale University School of Medicine, New Haven, CT, USA
| | - Eve C Tsai
- Neuroscience Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada.,Brain and Mind Research Institute, University of Ottawa, Ottawa, ON, Canada
| | - Michael E Hildebrand
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada.,Neuroscience Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada.,Brain and Mind Research Institute, University of Ottawa, Ottawa, ON, Canada
| |
Collapse
|
29
|
Lim JSY, Kam PCA. Neuroimmune mechanisms of pain: Basic science and potential therapeutic modulators. Anaesth Intensive Care 2020; 48:167-178. [DOI: 10.1177/0310057x20902774] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
This narrative review aims to describe the role of peripheral and central immune responses to tissue and nerve damage in animal models, and to discuss the use of immunomodulatory agents in clinical practice and their perioperative implications. Animal models of pain have demonstrated that nerve injury activates immune signalling pathways that drive aberrant sensory processes, resulting in neuropathic and chronic pain. This response involves the innate immune system. T lymphocytes are also recruited. Glial cells surrounding the damaged nerves release cytokines and proinflammatory mediators that activate resident immune cells and recruit circulatory immune cells. Toll-like receptors on the glial cells play a crucial role in the pathogenesis of chronic pain. Animal models indicate an immune mechanism of neuropathic pain. Analgesic drugs and anaesthetic agents have varied effects on the neuroimmune interface. Evidence of a neuroimmune interaction is mainly from animal studies. Human studies are required to evaluate the clinical implications of this neuroimmune interaction.
Collapse
Affiliation(s)
- Jessica SY Lim
- Department of Anaesthetics, Royal Prince Alfred Hospital, Sydney, Australia
| | - Peter CA Kam
- Department of Anaesthetics, Royal Prince Alfred Hospital, Sydney, Australia
- Discipline of Anaesthesia, Central Clinical School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| |
Collapse
|
30
|
Dworsky-Fried Z, Kerr BJ, Taylor AMW. Microbes, microglia, and pain. NEUROBIOLOGY OF PAIN 2020; 7:100045. [PMID: 32072077 PMCID: PMC7016021 DOI: 10.1016/j.ynpai.2020.100045] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 01/23/2020] [Accepted: 01/24/2020] [Indexed: 02/08/2023]
Abstract
Explore the connection between the gut microbiome and microglia in chronic pain. Discuss mechanisms by which gut bacteria might influence microglia to contribute to chronic pain. Highlight gaps in knowledge and discuss future directions for the field.
Globally, it is estimated that one in five people suffer from chronic pain, with prevalence increasing with age. The pathophysiology of chronic pain encompasses complex sensory, immune, and inflammatory interactions within both the central and peripheral nervous systems. Microglia, the resident macrophages of the central nervous system (CNS), are critically involved in the initiation and persistence of chronic pain. Microglia respond to local signals from the CNS but are also modulated by signals from the gastrointestinal tract. Emerging data from preclinical and clinical studies suggest that communication between the gut microbiome, the community of bacteria residing within the gut, and microglia is involved in producing chronic pain. Targeted strategies that manipulate or restore the gut microbiome have been shown to reduce microglial activation and alleviate symptoms associated with inflammation. These data indicate that manipulations of the gut microbiome in chronic pain patients might be a viable strategy in improving pain outcomes. Herein, we discuss the evidence for a connection between microglia and the gut microbiome and explore the mechanisms by which commensal bacteria might influence microglial reactivity to drive chronic pain.
Collapse
Affiliation(s)
- Zoë Dworsky-Fried
- Department of Pharmacology, University of Alberta, Edmonton T6G2H7, Canada
| | - Bradley J Kerr
- Department of Pharmacology, University of Alberta, Edmonton T6G2H7, Canada.,Neuroscience and Mental Health Institute, University of Alberta, Edmonton T6G2H7, Canada.,Department of Anesthesiology and Pain Medicine, University of Alberta, Edmonton T6G2H7, Canada
| | - Anna M W Taylor
- Department of Pharmacology, University of Alberta, Edmonton T6G2H7, Canada.,Neuroscience and Mental Health Institute, University of Alberta, Edmonton T6G2H7, Canada.,Department of Anesthesiology and Pain Medicine, University of Alberta, Edmonton T6G2H7, Canada
| |
Collapse
|
31
|
Abstract
Astrocytes are critical for maintaining the homeostasis of the CNS. Increasing evidence suggests that a number of neurological and neuropsychiatric disorders, including chronic pain, may result from astrocyte 'gliopathy'. Indeed, in recent years there has been substantial progress in our understanding of how astrocytes can regulate nociceptive synaptic transmission via neuronal-glial and glial-glial cell interactions, as well as the involvement of spinal and supraspinal astrocytes in the modulation of pain signalling and the maintenance of neuropathic pain. A role of astrocytes in the pathogenesis of chronic itch is also emerging. These developments suggest that targeting the specific pathways that are responsible for astrogliopathy may represent a novel approach to develop therapies for chronic pain and chronic itch.
Collapse
|
32
|
Abstract
Neuropathic pain (NP) is an increasingly common chronic pain state and a major health burden, affecting approximately 7% to 10% of the general population. Emerging evidence suggests that genetic factors could partially explain individual susceptibility to NP and the estimated heritability in twins is 37%. The aim of this study was to systematically review and summarize the studies in humans that have investigated the influence of genetic factors associated with NP. We conducted a comprehensive literature search and performed meta-analyses of all the potential genetic variants associated with NP. We reviewed 29 full-text articles and identified 28 genes that were significantly associated with NP, mainly involved in neurotransmission, immune response, and metabolism. Genetic variants in HLA genes, COMT, OPRM1, TNFA, IL6, and GCH1, were found to have an association with NP in more than one study. In the meta-analysis, polymorphisms in HLA-DRB1*13 (odds ratio [OR], 2.96; confidence interval [CI], 1.93-4.56), HLA-DRB1*04 (OR, 1.40; CI, 1.02-1.93), HLA-DQB1*03 (OR, 2.86; CI, 1.57-5.21), HLA-A*33 (OR, 2.32; CI, 1.42-3.80), and HLA-B*44 (OR, 3.17; CI, 2.22-4.55) were associated with significantly increased risk of developing NP, whereas HLA-A*02 (OR, 0.64; CI, 0.47-0.87) conferred reduced risk and neither rs1799971 in OPRM1 (OR, 0.55; CI, 0.27-1.11) nor rs4680 in COMT (OR, 0.95; CI, 0.81-1.13) were significantly associated with NP. These findings demonstrate an important and specific contribution of genetic factors to the risk of developing NP. However, large-scale replication studies are required to validate these candidate genes. Our review also highlights the need for genome-wide association studies with consistent case definition to elucidate the genetic architecture underpinning NP.
Collapse
|
33
|
Diverse Role of Biological Plasticity in Low Back Pain and Its Impact on Sensorimotor Control of the Spine. J Orthop Sports Phys Ther 2019; 49:389-401. [PMID: 31151376 DOI: 10.2519/jospt.2019.8716] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Pain is complex. It is no longer acceptable to consider pain solely as a peripheral phenomenon involving activation of nociceptive neurons. The contemporary understanding of pain involves consideration of different underlying pain mechanisms and an increasing awareness of plasticity in all of the biological systems. Of note, recent advances in technology and understanding have highlighted the critical importance of neuroimmune interactions, both in the peripheral and central nervous systems, and the interaction between the nervous system and body tissues in the development and maintenance of pain, including low back pain (LBP). Further, the biology of many tissues changes when challenged by pain and injury, as reported in a growing body of literature on the biology of muscle, fat, and connective tissue. These advances in understanding of the complexity of LBP have implications for our understanding of pain and its interaction with the motor system, and may change how we consider motor control in the rehabilitation of LBP. This commentary provides a state-of-the-art overview of plasticity of biology in LBP. The paper is divided into 4 parts that address (1) biology of pain mechanisms, (2) neuroimmune interaction in the central nervous system, (3) neuroimmune interaction in the periphery, and (4) brain and peripheral tissue interaction. Each section considers the implications for clinical management of LBP. J Orthop Sports Phys Ther 2019;49(6):389-401. doi:10.2519/jospt.2019.8716.
Collapse
|
34
|
Beazley-Long N, Moss CE, Ashby WR, Bestall SM, Almahasneh F, Durrant AM, Benest AV, Blackley Z, Ballmer-Hofer K, Hirashima M, Hulse RP, Bates DO, Donaldson LF. VEGFR2 promotes central endothelial activation and the spread of pain in inflammatory arthritis. Brain Behav Immun 2018; 74:49-67. [PMID: 29548992 PMCID: PMC6302073 DOI: 10.1016/j.bbi.2018.03.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 03/02/2018] [Accepted: 03/11/2018] [Indexed: 02/01/2023] Open
Abstract
Chronic pain can develop in response to conditions such as inflammatory arthritis. The central mechanisms underlying the development and maintenance of chronic pain in humans are not well elucidated although there is evidence for a role of microglia and astrocytes. However in pre-clinical models of pain, including models of inflammatory arthritis, there is a wealth of evidence indicating roles for pathological glial reactivity within the CNS. In the spinal dorsal horn of rats with painful inflammatory arthritis we found both a significant increase in CD11b+ microglia-like cells and GFAP+ astrocytes associated with blood vessels, and the number of activated blood vessels expressing the adhesion molecule ICAM-1, indicating potential glio-vascular activation. Using pharmacological interventions targeting VEGFR2 in arthritic rats, to inhibit endothelial cell activation, the number of dorsal horn ICAM-1+ blood vessels, CD11b+ microglia and the development of secondary mechanical allodynia, an indicator of central sensitization, were all prevented. Targeting endothelial VEGFR2 by inducible Tie2-specific VEGFR2 knock-out also prevented secondary allodynia in mice and glio-vascular activation in the dorsal horn in response to inflammatory arthritis. Inhibition of VEGFR2 in vitro significantly blocked ICAM-1-dependent monocyte adhesion to brain microvascular endothelial cells, when stimulated with inflammatory mediators TNF-α and VEGF-A165a. Taken together our findings suggest that a novel VEGFR2-mediated spinal cord glio-vascular mechanism may promote peripheral CD11b+ circulating cell transmigration into the CNS parenchyma and contribute to the development of chronic pain in inflammatory arthritis. We hypothesise that preventing this glio-vascular activation and circulating cell translocation into the spinal cord could be a new therapeutic strategy for pain caused by rheumatoid arthritis.
Collapse
Affiliation(s)
- Nicholas Beazley-Long
- Arthritis Research UK Pain Centre & School of Life Sciences, Medical School, University of Nottingham, Nottingham NG7 2UH, UK.
| | - Catherine Elizabeth Moss
- Arthritis Research UK Pain Centre & School of Life Sciences, Medical School, University of Nottingham, Nottingham NG7 2UH, UK
| | - William Robert Ashby
- Arthritis Research UK Pain Centre & School of Life Sciences, Medical School, University of Nottingham, Nottingham NG7 2UH, UK
| | - Samuel Marcus Bestall
- Cancer Biology, School of Medicine, QMC, University of Nottingham, Nottingham NG7 2UH, UK
| | - Fatimah Almahasneh
- Arthritis Research UK Pain Centre & School of Life Sciences, Medical School, University of Nottingham, Nottingham NG7 2UH, UK
| | - Alexandra Margaret Durrant
- Arthritis Research UK Pain Centre & School of Life Sciences, Medical School, University of Nottingham, Nottingham NG7 2UH, UK
| | - Andrew Vaughan Benest
- Cancer Biology, School of Medicine, QMC, University of Nottingham, Nottingham NG7 2UH, UK
| | - Zoe Blackley
- Cancer Biology, School of Medicine, QMC, University of Nottingham, Nottingham NG7 2UH, UK
| | | | - Masanori Hirashima
- Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Japan
| | - Richard Phillip Hulse
- Cancer Biology, School of Medicine, QMC, University of Nottingham, Nottingham NG7 2UH, UK
| | - David Owen Bates
- Cancer Biology, School of Medicine, QMC, University of Nottingham, Nottingham NG7 2UH, UK,COMPARE University of Birmingham and University of Nottingham Midlands, UK
| | - Lucy Frances Donaldson
- Arthritis Research UK Pain Centre & School of Life Sciences, Medical School, University of Nottingham, Nottingham NG7 2UH, UK
| |
Collapse
|
35
|
A new hypothesis for the pathophysiology of complex regional pain syndrome. Med Hypotheses 2018; 119:41-53. [DOI: 10.1016/j.mehy.2018.07.026] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 07/18/2018] [Accepted: 07/27/2018] [Indexed: 12/21/2022]
|
36
|
Birklein F, Ibrahim A, Schlereth T, Kingery WS. The Rodent Tibia Fracture Model: A Critical Review and Comparison With the Complex Regional Pain Syndrome Literature. THE JOURNAL OF PAIN 2018; 19:1102.e1-1102.e19. [PMID: 29684510 PMCID: PMC6163066 DOI: 10.1016/j.jpain.2018.03.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 02/28/2018] [Accepted: 03/30/2018] [Indexed: 12/23/2022]
Abstract
Distal limb fracture is the most common cause of complex regional pain syndrome (CRPS), thus the rodent tibia fracture model (TFM) was developed to study CRPS pathogenesis. This comprehensive review summarizes the published TFM research and compares these experimental results with the CRPS literature. The TFM generated spontaneous and evoked pain behaviors, inflammatory symptoms (edema, warmth), and trophic changes (skin thickening, osteoporosis) resembling symptoms in early CRPS. Neuropeptides, inflammatory cytokines, and nerve growth factor (NGF) have been linked to pain behaviors, inflammation, and trophic changes in the TFM model and proliferating keratinocytes were identified as the primary source of cutaneous cytokines and NGF. Tibia fracture also activated spinal glia and upregulated spinal neuropeptide, cytokine, and NGF expression, and in the brain it changed dendritic architecture. B cell-expressed immunoglobulin M antibodies also contributed to pain behavior, indicating a role for adaptive immunity. These results modeled many findings in early CRPS, but significant differences were also noted. PERSPECTIVE Multiple neuroimmune signaling mechanisms contribute to the pain, inflammation, and trophic changes observed in the injured limb of the rodent TFM. This model replicates many of the symptoms, signs, and pathophysiology of early CRPS, but most post-fracture changes resolve within 5 months and may not contribute to perpetuating chronic CRPS.
Collapse
Affiliation(s)
- Frank Birklein
- University Medical Center of the Johannes Gutenberg University Mainz, Department of Neurology, Mainz, Germany
| | - Alaa Ibrahim
- University Medical Center of the Johannes Gutenberg University Mainz, Department of Neurology, Mainz, Germany
| | - Tanja Schlereth
- University Medical Center of the Johannes Gutenberg University Mainz, Department of Neurology, Mainz, Germany
| | - Wade S Kingery
- Palo Alto Veterans Institute for Research, Veterans Affairs Palo Alto Health Care System, Palo Alto, California.
| |
Collapse
|
37
|
Ibudilast produces anti-allodynic effects at the persistent phase of peripheral or central neuropathic pain in rats: Different inhibitory mechanism on spinal microglia from minocycline and propentofylline. Eur J Pharmacol 2018; 833:263-274. [DOI: 10.1016/j.ejphar.2018.06.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 06/06/2018] [Accepted: 06/06/2018] [Indexed: 12/13/2022]
|
38
|
Jung YH, Kim H, Jeon SY, Kwon JM, Lee WJ, Kim YC, Jang JH, Choi SH, Lee JY, Kang DH. Brain Metabolites and Peripheral Biomarkers Associated with Neuroinflammation in Complex Regional Pain Syndrome Using [11C]-(R)-PK11195 Positron Emission Tomography and Magnetic Resonance Spectroscopy: A Pilot Study. PAIN MEDICINE 2018; 20:504-514. [DOI: 10.1093/pm/pny111] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Ye-Ha Jung
- Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Korea
| | - Hyeonjin Kim
- Department of Radiology, Seoul National University Hospital, Seoul, Korea
| | - So Yeon Jeon
- Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Korea
| | - Jeong Min Kwon
- Department of Experimental Animal Research, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea
| | - Won Joon Lee
- Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Korea
| | - Yong Chul Kim
- Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul, Korea
| | - Joon Hwan Jang
- Department of Psychiatry, Seoul National University College of Medicine, Seoul, Korea
| | - Soo-Hee Choi
- Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Korea
- Department of Psychiatry and Institute of Human Behavioral Sciences, Seoul National University College of Medicine, Seoul, Korea
| | - Jun-Young Lee
- Department of Psychiatry and Behavioral Science, Seoul National University College of Medicine & SMG-SNU Boramae Medical Center, Seoul, Korea
| | - Do-Hyung Kang
- Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Korea
- Department of Psychiatry, Seoul National University College of Medicine, Seoul, Korea
| |
Collapse
|
39
|
Botulinum Toxin for Central Neuropathic Pain. Toxins (Basel) 2018; 10:toxins10060224. [PMID: 29857568 PMCID: PMC6024683 DOI: 10.3390/toxins10060224] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 05/26/2018] [Accepted: 05/28/2018] [Indexed: 11/17/2022] Open
Abstract
Botulinum toxin (BTX) is widely used to treat muscle spasticity by acting on motor neurons. Recently, studies of the effects of BTX on sensory nerves have been reported and several studies have been conducted to evaluate its effects on peripheral and central neuropathic pain. Central neuropathic pain includes spinal cord injury-related neuropathic pain, post-stroke shoulder pain, multiple sclerosis-related pain, and complex regional pain syndrome. This article reviews the mechanism of central neuropathic pain and assesses the effect of BTX on central neuropathic pain.
Collapse
|
40
|
Durrant A, Swift M, Beazley-Long N. A role for pericytes in chronic pain? Curr Opin Support Palliat Care 2018; 12:154-161. [PMID: 29553988 PMCID: PMC6027993 DOI: 10.1097/spc.0000000000000342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
PURPOSE OF REVIEW The importance of the blood-brain barrier (BBB) and neuroinflammation in neurodegenerative conditions is becoming increasingly apparent, yet very little is known about these neurovascular functions in nonmalignant disease chronic pain. Neural tissue pericytes play critical roles in the formation and maintenance of the BBB. Herein, we review the important roles of neural pericytes and address their potential role in chronic pain. RECENT FINDINGS Pericytes are implicated in the function of neural microvasculature, including BBB permeability, neuroimmune factor secretion and leukocyte transmigration. In addition, the multipotent stem cell nature of pericytes affords pericytes the ability to migrate into neural parenchyma and differentiate into pain-associated cell types. These recent findings indicate that pericytes are key players in pathological BBB disruption and neuroinflammation, and as such pericytes may be key players in chronic pain states. SUMMARY Pericytes play key roles in pathological processes associated with chronic pain. We propose that pericytes may be a therapeutic target for painful diseases that have associated neural vascular dysfunction. Given the paucity of new pharmacotherapies for chronic pain conditions, we hope that this review inspires researchers to unearth the potential role(s) of pericytes in chronic pain sowing the seeds for future new chronic pain therapies.
Collapse
Affiliation(s)
- A.M. Durrant
- Arthritis Research UK Pain Centre & School of Life Sciences, Medical School, University of Nottingham, Nottingham NG7 2UH
| | - M.N Swift
- Arthritis Research UK Pain Centre & School of Life Sciences, Medical School, University of Nottingham, Nottingham NG7 2UH
| | - N. Beazley-Long
- Arthritis Research UK Pain Centre & School of Life Sciences, Medical School, University of Nottingham, Nottingham NG7 2UH
| |
Collapse
|
41
|
Beazley-Long N, Durrant AM, Swift MN, Donaldson LF. The physiological functions of central nervous system pericytes and a potential role in pain. F1000Res 2018; 7:341. [PMID: 29623199 PMCID: PMC5861511 DOI: 10.12688/f1000research.13548.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/16/2018] [Indexed: 12/29/2022] Open
Abstract
Central nervous system (CNS) pericytes regulate critical functions of the neurovascular unit in health and disease. CNS pericytes are an attractive pharmacological target for their position within the neurovasculature and for their role in neuroinflammation. Whether the function of CNS pericytes also affects pain states and nociceptive mechanisms is currently not understood. Could it be that pericytes hold the key to pain associated with CNS blood vessel dysfunction? This article reviews recent findings on the important physiological functions of CNS pericytes and highlights how these neurovascular functions could be linked to pain states.
Collapse
Affiliation(s)
- Nicholas Beazley-Long
- Arthritis Research UK Pain Centre & School of Life Sciences, Medical School, University of Nottingham, Nottingham, UK
| | - Alexandra M Durrant
- Arthritis Research UK Pain Centre & School of Life Sciences, Medical School, University of Nottingham, Nottingham, UK
| | - Matthew N Swift
- Arthritis Research UK Pain Centre & School of Life Sciences, Medical School, University of Nottingham, Nottingham, UK
| | - Lucy F Donaldson
- Arthritis Research UK Pain Centre & School of Life Sciences, Medical School, University of Nottingham, Nottingham, UK
| |
Collapse
|
42
|
Microglia in neuropathic pain: cellular and molecular mechanisms and therapeutic potential. Nat Rev Neurosci 2018; 19:138-152. [DOI: 10.1038/nrn.2018.2] [Citation(s) in RCA: 365] [Impact Index Per Article: 60.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
43
|
Abstract
PURPOSE OF REVIEW The review aims to present the latest research into microglia and their role in pain. RECENT FINDINGS Microglia affect sex and age-dependent differences in pain. The various microglial phenotypes make their involvement in pain more complex but provide more potential as pain modulators. SUMMARY Glial cells, composed of microglia, astrocytes, and oligodendrocytes, outnumber neurons in the central nervous system. The crosstalk between these cells and neurons is now established as participating in the development of chronic pain. There has been a great advance in the description of microglia reactivity from pro to anti-inflammatory phenotypes. The modulation of these phenotypes could be a potential target for pain therapy. Recently, different microglial reactivity between man and woman and between neonates and adults, in response to nerve injury were described, which could explain some of the sex differences in pain sensitivity and the absence of neuropathic pain development in neonates. Clinical trials using microglia as a target have been carried out in various neurological diseases and pain, with limited efficacy in the latter, but there are nonetheless, indications that with some improvement in study strategies microglia could be a future target for pain control.
Collapse
|
44
|
Choi H, Roh D, Yoon S, Choi S, Kwon S, Kang S, Moon J, Han H, Beitz AJ, Lee J. Differential involvement of ipsilateral and contralateral spinal cord astrocyte D-serine in carrageenan-induced mirror-image pain: role of σ1 receptors and astrocyte gap junctions. Br J Pharmacol 2018; 175:558-572. [PMID: 29172248 PMCID: PMC5773966 DOI: 10.1111/bph.14109] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 11/04/2017] [Accepted: 11/17/2017] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE Although we have recently demonstrated that spinal astrocyte gap junctions mediate the development of mirror-image pain (MIP), it is still unclear which astrocyte-derived factor is responsible for the development of MIP and how its production is controlled. In the present study, we focused on the role of ipsilateral versus contralateral D-serine in the development of MIP and investigated the possible involvement of σ1 receptors and gap junctions in astrocyte D-serine production. EXPERIMENTAL APPROACH Following carrageenan injection, mechanical allodynia was tested at various time points to examine the effect of individual drugs. Immunohistochemistry and Western blot analyses were performed to clarify the expression levels of spinal D-serine, serine racemase, σ1 receptors and connexin 43. KEY RESULTS The expression of ipsilateral D-serine was up-regulated during the early phase of inflammation, while contralateral D-serine increased during the later phase of inflammation. The pharmacological inhibition of D-serine during the early phase blocked the development of both ipsilateral and contralateral mechanical allodynia. However, the inhibition of D-serine during the later phase of inflammation blocked contralateral, but not ipsilateral mechanical allodynia. Furthermore, the inhibition of σ1 receptors during the earlier phase of inflammation inhibited the increase in ipsilateral D-serine. Conversely, the blockade of astrocyte gap junctions suppressed the up-regulation of contralateral D-serine during the later phase of inflammation. CONCLUSION AND IMPLICATIONS Spinal astrocyte D-serine plays an important role in the development of mirror-image pain. Furthermore, σ1 receptors and astrocyte gap junction signalling mediate ipsilateral and contralateral D-serine production respectively.
Collapse
Affiliation(s)
- Hoon‐Seong Choi
- Department of Veterinary Physiology, BK21 PLUS Program for Creative Veterinary Science Research, Research Institute for Veterinary Science and College of Veterinary MedicineSeoul National UniversitySeoulKorea
| | - Dae‐Hyun Roh
- Department of Oral Physiology, School of DentistryKyung Hee UniversitySeoulKorea
| | - Seo‐Yeon Yoon
- Pain Cognitive Function Research Center, Department of Brain and Cognitive Sciences, College of Natural SciencesSeoul National UniversitySeoulKorea
| | - Sheu‐Ran Choi
- Department of Veterinary Physiology, BK21 PLUS Program for Creative Veterinary Science Research, Research Institute for Veterinary Science and College of Veterinary MedicineSeoul National UniversitySeoulKorea
| | | | - Suk‐Yun Kang
- KM Fundamental Research DivisionKorea Institute of Oriental MedicineDaejeonKorea
| | - Ji‐Young Moon
- Animal Protection & Welfare DivisionAnimal and Plant Quarantine AgencyGimcheonKorea
| | - Ho‐Jae Han
- Department of Veterinary Physiology, BK21 PLUS Program for Creative Veterinary Science Research, Research Institute for Veterinary Science and College of Veterinary MedicineSeoul National UniversitySeoulKorea
| | - Alvin J Beitz
- Department of Veterinary and Biomedical Sciences, College of Veterinary MedicineUniversity of MinnesotaSaint PaulMNUSA
| | - Jang‐Hern Lee
- Department of Veterinary Physiology, BK21 PLUS Program for Creative Veterinary Science Research, Research Institute for Veterinary Science and College of Veterinary MedicineSeoul National UniversitySeoulKorea
| |
Collapse
|
45
|
Albrecht DS, Normandin MD, Shcherbinin S, Wooten DW, Schwarz AJ, Zürcher NR, Barth VN, Guehl NJ, Akeju O, Atassi N, Veronese M, Turkheimer F, Hooker JM, Loggia ML. Pseudoreference Regions for Glial Imaging with 11C-PBR28: Investigation in 2 Clinical Cohorts. J Nucl Med 2018; 59:107-114. [PMID: 28818984 PMCID: PMC5750517 DOI: 10.2967/jnumed.116.178335] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 07/17/2017] [Indexed: 12/12/2022] Open
Abstract
The translocator protein (TSPO) is a commonly used imaging target to investigate neuroinflammation. Although TSPO imaging demonstrates great promise, its signal exhibits substantial interindividual variability, which needs to be accounted for to uncover group effects that are truly reflective of neuroimmune activation. Recent evidence suggests that relative metrics computed using pseudoreference approaches can minimize within-group variability and increase sensitivity to detect physiologically meaningful group differences. Here, we evaluated various ratio approaches for TSPO imaging and compared them with standard kinetic modeling techniques, analyzing 2 different disease cohorts. Patients with chronic low back pain (cLBP) or amyotrophic lateral sclerosis (ALS) and matching healthy controls received 11C-PBR28 PET scans. The occipital cortex, cerebellum and whole brain were first evaluated as candidate pseudoreference regions by testing for the absence of group differences in SUV and distribution volume (VT) estimated with an arterial input function. The SUV from target regions (cLBP study, thalamus; ALS study, precentral gyrus) was normalized with the SUV from candidate pseudoreference regions (i.e., occipital cortex, cerebellum, and whole brain) to obtain SUVRoccip, SUVRcereb, and SUVRWB The sensitivity to detect group differences in target regions was compared using various SUVR approaches, as well as distribution volume ratio (DVR) estimated with (blDVR) or without arterial input function (refDVR), and VT Additional voxelwise SUVR group analyses were performed. We observed no significant group differences in pseudoreference VT or SUV, excepting whole-brain VT, which was higher in cLBP patients than controls. Target VT elevations in patients (P = 0.028 and 0.051 in cLBP and ALS, respectively) were similarly detected by SUVRoccip and SUVRWB, and by refDVR and blDVR (less reliably by SUVRcereb). In voxelwise analyses, SUVRoccip, but not SUVRcereb, identified regional group differences initially observed with SUVRWB, and in additional areas suspected to be affected in the pathology examined. All ratio metrics were highly cross-correlated, but generally were not associated with VT. Although important caveats need to be considered when using relative metrics, ratio analyses appear to be similarly sensitive to detect pathology-related group differences in 11C-PBR28 signal as classic kinetic modeling techniques. The occipital cortex may be a suitable pseudoreference region, at least for the populations evaluated, pending further validation in larger cohorts.
Collapse
Affiliation(s)
- Daniel S Albrecht
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
- Gordon Center for Medical Imaging, NMMI, Radiology Department, Massachusetts General Hospital & Harvard Medical School, Boston, Massachusetts
| | - Marc D Normandin
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
| | | | - Dustin W Wooten
- Gordon Center for Medical Imaging, NMMI, Radiology Department, Massachusetts General Hospital & Harvard Medical School, Boston, Massachusetts
| | | | - Nicole R Zürcher
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
| | | | - Nicolas J Guehl
- Gordon Center for Medical Imaging, NMMI, Radiology Department, Massachusetts General Hospital & Harvard Medical School, Boston, Massachusetts
| | - Oluwaseun Akeju
- Department of Anesthesiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Nazem Atassi
- Neurological Clinical Research Institute, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts; and
| | - Mattia Veronese
- Department of Neuroimaging, Institute of Psychiatry, King's College London, London, United Kingdom
| | - Federico Turkheimer
- Department of Neuroimaging, Institute of Psychiatry, King's College London, London, United Kingdom
| | - Jacob M Hooker
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
| | - Marco L Loggia
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
| |
Collapse
|
46
|
IL4-10 Fusion Protein Is a Novel Drug to Treat Persistent Inflammatory Pain. J Neurosci 2017; 36:7353-63. [PMID: 27413147 DOI: 10.1523/jneurosci.0092-16.2016] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 05/18/2016] [Indexed: 12/30/2022] Open
Abstract
UNLABELLED Chronic pain is a major clinical problem that is difficult to treat and requires novel therapies. Although most pain therapies primarily target neurons, neuroinflammatory processes characterized by spinal cord and dorsal root ganglion production of proinflammatory cytokines play an important role in persistent pain states and represent potential therapeutic targets. Anti-inflammatory cytokines are attractive candidates to regulate aberrant neuroinflammatory processes, but the therapeutic potential of these cytokines as stand-alone drugs is limited. Their optimal function requires concerted actions with other regulatory cytokines, and their relatively small size causes rapid clearance. To overcome these limitations, we developed a fusion protein of the anti-inflammatory cytokines interleukin 4 (IL4) and IL10. The IL4-10 fusion protein is a 70 kDa glycosylated dimeric protein that retains the functional activity of both cytokine moieties. Intrathecal administration of IL4-10 dose-dependently inhibited persistent inflammatory pain in mice: three IL4-10 injections induced full resolution of inflammatory pain in two different mouse models of persistent inflammatory pain. Both cytokine moieties were required for optimal effects. The IL4-10 fusion protein was more effective than the individual cytokines or IL4 plus IL10 combination therapy and also inhibited allodynia in a mouse model of neuropathic pain. Mechanistically, IL4-10 inhibited the activity of glial cells and reduced spinal cord and dorsal root ganglion cytokine levels without affecting paw inflammation. In conclusion, we developed a novel fusion protein with improved efficacy to treat pain, compared with wild-type anti-inflammatory cytokines. The IL4-10 fusion protein has potential as a treatment for persistent inflammatory pain. SIGNIFICANCE STATEMENT The treatment of chronic pain is a major clinical and societal challenge. Current therapies to treat persistent pain states are limited and often cause major side effects. Therefore, novel analgesic treatments are urgently needed. In search of a novel drug to treat chronic pain, we developed a fusion protein consisting of two prototypic regulatory cytokines, interleukin 4 (IL4) and IL10. The work presented in this manuscript shows that this IL4-10 fusion protein overcomes some major therapeutic limitations of pain treatment with individual cytokines. The IL4-10 fusion protein induces full resolution of persistent inflammatory pain in two different mouse models. These novel findings are significant, as they highlight the IL4-10 fusion protein as a long-needed potential new drug to stop persistent pain states.
Collapse
|
47
|
Mapplebeck JCS, Beggs S, Salter MW. Molecules in pain and sex: a developing story. Mol Brain 2017; 10:9. [PMID: 28270169 PMCID: PMC5341415 DOI: 10.1186/s13041-017-0289-8] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 02/23/2017] [Indexed: 11/17/2022] Open
Abstract
Microglia are dynamic immune cells with diverse roles in maintaining homeostasis of the central nervous system. Dysregulation of microglia has been critically implicated in the genesis of neuropathic pain. Peripheral nerve injury, a common cause of neuropathic pain, engages microglia-neuronal signalling which causes disinhibition and facilitated excitation of spinal nociceptive pathways. However, recent literature indicates that the role of microglia in neuropathic pain is sexually dimorphic, and that female pain processing appears to be independent of microglia, depending rather on T cells. Despite this sex difference, pain signalling in the spinal cord converges downstream of microglia, as NMDAR-mediated facilitated excitation in pain transmitting neurons is consistent between males and females. Determining whether pain signalling is sexually dimorphic in humans and, further, addressing the sex bias in pain research will increase the translational relevance of preclinical findings and advance our understanding of chronic pain in women.
Collapse
Affiliation(s)
- Josiane C S Mapplebeck
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada.,University of Toronto Centre for the Study of Pain, Toronto, ON, Canada
| | - Simon Beggs
- Developmental Neurosciences Programme, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Michael W Salter
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, ON, Canada. .,Department of Physiology, University of Toronto, Toronto, ON, Canada. .,University of Toronto Centre for the Study of Pain, Toronto, ON, Canada.
| |
Collapse
|
48
|
Reversal of TRESK Downregulation Alleviates Neuropathic Pain by Inhibiting Activation of Gliocytes in the Spinal Cord. Neurochem Res 2017; 42:1288-1298. [PMID: 28160200 DOI: 10.1007/s11064-016-2170-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Revised: 11/03/2016] [Accepted: 12/28/2016] [Indexed: 10/20/2022]
Abstract
Despite the consensus that activation of TWIK-related spinal cord K+ (TRESK) might contribute to the pathogenesis of chronic pain, the specific mechanisms underlying the transfer and development of pain signals still remain obscure. In the present study, we validated that TRESK was expressed in neurons instead of glial cells. Furthermore, in the SNI model of neuropathic pain (NP), downregulation of TRESK in spinal cord neurons resulted in upregulation of connexin 36 (Cx36) and connexin 43 (Cx43), both being subtypes of gap junctions in the spinal cord, with gliocytes in the spinal cord activated ultimately. Compared with SNI rats, intrathecal injection of TRESK gene recombinant adenovirus significantly downregulated the expression levels of Cx36 and Cx43 and suppressed the activation of gliocytes in the spinal cord, with hyperalgesia significantly reduced. In conclusion, TRESK contributes to the pathogenesis of NP by upregulation of synaptic transmission and activation of gliocytes.
Collapse
|
49
|
Weinstock LB, Myers TL, Walters AS, Schwartz OA, Younger JW, Chopra PJ, Guarino AH. Identification and Treatment of New Inflammatory Triggers for Complex Regional Pain Syndrome: Small Intestinal Bacterial Overgrowth and Obstructive Sleep Apnea. ACTA ACUST UNITED AC 2017; 6:272-6. [PMID: 26867023 DOI: 10.1213/xaa.0000000000000292] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Complex regional pain syndrome (CRPS) is evoked by conditions that may be associated with local and/or systemic inflammation. We present a case of long-standing CRPS in a patient with Ehlers-Danlos syndrome in which prolonged remission was attained by directing therapy toward concomitant small intestinal bacterial overgrowth, obstructive sleep apnea, and potential increased microglia activity. We theorize that cytokine production produced by small intestinal bacterial overgrowth and obstructive sleep apnea may act as stimuli for ongoing CRPS symptoms. CRPS may also benefit from the properties of low-dose naltrexone that blocks microglia Toll-like receptors and induces production of endorphins that regulate and reduce inflammation.
Collapse
Affiliation(s)
- Leonard B Weinstock
- From the Departments of *Anesthesia and †Internal Medicine, Washington University School of Medicine, St. Louis, Missouri; ‡Specialists in Gastroenterology, LLC, St. Louis, Missouri; §Department of Neurology, Vanderbilt University, Nashville, Tennessee; ‖Sleep and EEG Laboratory, Barnes Jewish West County, BJC Medical Group Center for Sleep Medicine, St. Louis, Missouri; Departments of ¶Psychology, #Anesthesiology, and **Rheumatology, Neuroinflammation, Pain and Fatigue Lab, University of Alabama, Birmingham, Alabama; ††Pain Management Center, Department of Anesthesia, Warren Alpert Medical School of Brown University, Providence, Rhode Island; and ‡‡Department of Anesthesia, Washington University School of Medicine, St. Louis, Missouri
| | | | | | | | | | | | | |
Collapse
|
50
|
Jeon SY, Seo S, Lee JS, Choi SH, Lee DH, Jung YH, Song MK, Lee KJ, Kim YC, Kwon HW, Im HJ, Lee DS, Cheon GJ, Kang DH. [11C]-(R)-PK11195 positron emission tomography in patients with complex regional pain syndrome: A pilot study. Medicine (Baltimore) 2017; 96:e5735. [PMID: 28072713 PMCID: PMC5228673 DOI: 10.1097/md.0000000000005735] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Complex regional pain syndrome (CRPS) is characterized by severe and chronic pain, but the pathophysiology of this disease are not clearly understood. The primary aim of our case-control study was to explore neuroinflammation in patients with CRPS using positron emission tomography (PET), with an 18-kDa translocator protein specific radioligand [C]-(R)-PK11195. [C]-(R)-PK11195 PET scans were acquired for 11 patients with CRPS (30-55 years) and 12 control subjects (30-52 years). Parametric image of distribution volume ratio (DVR) for each participant was generated by applying a relative equilibrium-based graphical analysis. The DVR of [C]-(R)-PK11195 in the caudate nucleus (t(21) = -3.209, P = 0.004), putamen (t(21) = -2.492, P = 0.022), nucleus accumbens (t(21) = -2.218, P = 0.040), and thalamus (t(21) = -2.395, P = 0.026) were significantly higher in CRPS patients than in healthy controls. Those of globus pallidus (t(21) = -2.045, P = 0.054) tended to be higher in CRPS patients than in healthy controls. In patients with CRPS, there was a positive correlation between the DVR of [C]-(R)-PK11195 in the caudate nucleus and the pain score, the visual analog scale (r = 0.661, P = 0.026, R = 0.408) and affective subscales of McGill Pain Questionnaire (r = 0.604, P = 0.049, R = 0.364). We demonstrated that neuroinflammation of CRPS patients in basal ganglia. Our results suggest that microglial pathology can be an important pathophysiology of CRPS. Association between the level of caudate nucleus and pain severity indicated that neuroinflammation in this region might play a key role. These results may be essential for developing effective medical treatments.
Collapse
Affiliation(s)
- So Yeon Jeon
- Department of Neuropsychiatry, Seoul National University Hospital
| | - Seongho Seo
- Department of Nuclear Medicine, Seoul National University College of Medicine
- Department of Brain and Cognitive Science, Seoul National University College of Natural Sciences
| | - Jae Sung Lee
- Department of Nuclear Medicine, Seoul National University College of Medicine
- Department of Brain and Cognitive Science, Seoul National University College of Natural Sciences
- Institute of Radiation Medicine, Medical Research Center
| | - Soo-Hee Choi
- Department of Neuropsychiatry, Seoul National University Hospital
- Department of Psychiatry, Seoul National University College of Medicine
| | - Do-Hyeong Lee
- Department of Neuropsychiatry, Seoul National University Hospital
| | - Ye-Ha Jung
- Department of Neuropsychiatry, Seoul National University Hospital
| | - Man-Kyu Song
- Department of Neuropsychiatry, Seoul National University Hospital
| | - Kyung-Jun Lee
- Department of Neuropsychiatry, Seoul National University Hospital
| | - Yong Chul Kim
- Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul
| | - Hyun Woo Kwon
- Department of Nuclear Medicine, Seoul National University College of Medicine
- Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Suwon, Republic of Korea
| | - Hyung-Jun Im
- Department of Nuclear Medicine, Seoul National University College of Medicine
- Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Suwon, Republic of Korea
| | - Dong Soo Lee
- Department of Nuclear Medicine, Seoul National University College of Medicine
- Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Suwon, Republic of Korea
| | - Gi Jeong Cheon
- Department of Nuclear Medicine, Seoul National University College of Medicine
- Institute of Radiation Medicine, Medical Research Center
| | - Do-Hyung Kang
- Department of Neuropsychiatry, Seoul National University Hospital
- Department of Psychiatry, Seoul National University College of Medicine
| |
Collapse
|