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Mousavi Z, Karimi Z, Wong A, Cheraghloo N, Bagheri H, Bagheri R. Comparison of enjoyment and energy expenditure of exergame with and without blood flow restriction in men and women. Sci Rep 2024; 14:9030. [PMID: 38641659 PMCID: PMC11031571 DOI: 10.1038/s41598-024-59379-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 04/10/2024] [Indexed: 04/21/2024] Open
Abstract
This study compared the effects of blood flow restriction (BFR) on intensity and perceived enjoyment during an exergame. Fourteen healthy young participants engaged in a boxing exergame for 20 min, with or without BFR, across two sessions. Perceived enjoyment levels were assessed using the Physical Activity Enjoyment Scale. Heart rate was monitored, and energy expenditure (EE) during exercise was calculated. A mixed model analysis of variance with repeated measures was used to evaluate differences in EE and enjoyment between exergame conditions (with and without BFR) as well as the interaction effects of these protocols with gender. Although not statistically significant, perceived enjoyment decreased with BFR inclusion for both genders. No significant differences were observed between men and women for both protocols. Regarding EE, there was no significant difference between the two groups (with and without BFR). However, a significant main effect of gender was found, with men exhibiting higher EE values in both protocols compared to women. In conclusion, exergames incorporating BFR impact perceptual responses, particularly perceived enjoyment. Furthermore, significant gender differences in EE were found, with men displaying higher values.
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Affiliation(s)
- Zeynabalsadat Mousavi
- Nutrition and Food Service, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran
| | - Zohreh Karimi
- Department of Physical Education and Sport Sciences, Science and Research Branch, Islamic Azad University, Tehran, Iran.
| | - Alexei Wong
- Department of Health and Human Performance, Marymount University, Arlington, USA
| | - Neda Cheraghloo
- Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Hessan Bagheri
- Department of General Psychology, Islamic Azad University, South Tehran Branch, Tehran, Iran
| | - Reza Bagheri
- Department of Exercise Physiology, University of Isfahan, Isfahan, Iran
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Ye Q, Li J, Ren WJ, Zhang Y, Wang T, Rubini P, Yin HY, Illes P, Tang Y. Astrocyte activation in hindlimb somatosensory cortex contributes to electroacupuncture analgesia in acid-induced pain. Front Neurol 2024; 15:1348038. [PMID: 38633538 PMCID: PMC11021577 DOI: 10.3389/fneur.2024.1348038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 03/11/2024] [Indexed: 04/19/2024] Open
Abstract
Background Several studies have confirmed the direct relationship between extracellular acidification and the occurrence of pain. As an effective pain management approach, the mechanism of electroacupuncture (EA) treatment of acidification-induced pain is not fully understood. The purpose of this study was to assess the analgesic effect of EA in this type of pain and to explore the underlying mechanism(s). Methods We used plantar injection of the acidified phosphate-buffered saline (PBS; pH 6.0) to trigger thermal hyperalgesia in male Sprague-Dawley (SD) rats aged 6-8 weeks. The value of thermal withdrawal latency (TWL) was quantified after applying EA stimulation to the ST36 acupoint and/or chemogenetic control of astrocytes in the hindlimb somatosensory cortex. Results Both EA and chemogenetic astrocyte activation suppressed the acid-induced thermal hyperalgesia in the rat paw, whereas inhibition of astrocyte activation did not influence the hyperalgesia. At the same time, EA-induced analgesia was blocked by chemogenetic inhibition of astrocytes. Conclusion The present results suggest that EA-activated astrocytes in the hindlimb somatosensory cortex exert an analgesic effect on acid-induced pain, although these astrocytes might only moderately regulate acid-induced pain in the absence of EA. Our results imply a novel mode of action of astrocytes involved in EA analgesia.
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Affiliation(s)
- Qing Ye
- International Joint Research Centre on Purinergic Signalling, School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Jie Li
- Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Wen-Jing Ren
- International Joint Research Centre on Purinergic Signalling, School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Ying Zhang
- International Joint Research Centre on Purinergic Signalling, School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Tao Wang
- Chongqing Traditional Chinese Medicine Hospital, Chongqing, China
| | - Patrizia Rubini
- International Joint Research Centre on Purinergic Signalling, School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Hai-Yan Yin
- International Joint Research Centre on Purinergic Signalling, School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Peter Illes
- International Joint Research Centre on Purinergic Signalling, School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Rudolf Boehm Institute of Pharmacology and Toxicology, University of Leipzig, Leipzig, Germany
| | - Yong Tang
- International Joint Research Centre on Purinergic Signalling, School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Acupuncture and Chronobiology Key Laboratory of Sichuan Province, School of Health and Rehabilitation, Chengdu University of Traditional Chinese Medicine, Chengdu, China
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Starkweather AR, Xu W, Gnall KE, Emrich M, Garnsey CL, Magin ZE, Wu W, Fetta J, Groessl EJ, Park C. Testing Biological and Psychological Pathways of Emotion Regulation as a Primary Mechanism of Action in Yoga Interventions for Chronic Low Back Pain: Protocol for a Randomized Controlled Trial. JMIR Res Protoc 2024; 13:e56016. [PMID: 38483469 PMCID: PMC10979342 DOI: 10.2196/56016] [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: 01/11/2024] [Revised: 02/02/2024] [Accepted: 02/05/2024] [Indexed: 03/27/2024] Open
Abstract
BACKGROUND Interventions that promote adaptive emotion regulation (ER) skills reduce pain in patients with chronic pain; however, whether the effects of yoga practice on chronic low back pain (CLBP) are due to improvements in ER remains to be examined. OBJECTIVE This study will test whether the effects of yoga on CLBP (improved pain severity and interference) are mediated by improved ER, the extent to which effects are related to specific aspects of ER, and the role of pain sensitization as a mediator or moderator of effects. In this study, pain sensitization will be assessed by quantitative sensory testing and gene expression profiles to examine whether pain sensitization moderates yoga's effects on pain or whether yoga and ER abilities reduce pain sensitization, leading to decreased pain severity and interference. METHODS For this 2-arm parallel group blinded randomized controlled trial, we will enroll 204 adults with CLBP who will be randomized to receive the yoga (n=102) or a control stretching and strengthening (n=102) intervention, which are delivered via web-based synchronous biweekly 75-minute sessions over 12 weeks. Participants are encouraged to practice postures or exercises for 25 minutes on other days using accessible prerecorded practice videos that are sent to participants digitally. Participants will be assessed at 5 time points: baseline, midintervention (6 weeks), postintervention (12 weeks), and 3- and 6-month follow-ups. Assessments of ER, pain severity and interference, pain sensitivity including somatosensory and gene expression profiles, and physical strength and flexibility will be conducted at each visit. The fidelity of the interventions is assessed using a manualized checklist to evaluate recorded group sessions to ensure consistent instructor delivery. RESULTS The primary outcome will be the mean change in pain severity as measured by the Brief Pain Inventory-Short Form at 12 weeks. The primary mechanism of action is ER measured by change in the Difficulties in Emotion Regulation Scale total score. Secondary outcomes include pain sensitivity, physical strength and flexibility, pain interference, and quality of life. A mediation path analysis and series of moderated mediation path analyses will be conducted to test the study hypotheses. As of January 2024, we have enrolled 138 participants. We expect the study to be completed by May 2025. CONCLUSIONS The study will provide important data for evaluating whether improvements in ER are responsible for reduced pain perception and pain sensitivity as well as increased quality of life in the context of chronic pain. The study findings have important implications for determining the mechanism of action for yoga and possibly other mind-body interventions as nonpharmacological therapies for pain management. The results of the study will inform the content, delivery, and measures for intervention trials involving yoga as a modality for relieving pain and improving function. TRIAL REGISTRATION ClinicalTrials.gov NCT04678297; https://clinicaltrials.gov/study/NCT04678297. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID) DERR1-10.2196/56016.
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Affiliation(s)
- Angela R Starkweather
- Department of Biobehavioral Nursing Science, College of Nursing, University of Florida, Gainesville, FL, United States
| | - Wanli Xu
- School of Nursing, University of Connecticut, Storrs, CT, United States
| | - Katherine E Gnall
- Department of Psychological Sciences, University of Connecticut, Storrs, CT, United States
| | - Mariel Emrich
- Department of Psychological Sciences, University of Connecticut, Storrs, CT, United States
| | - Camille L Garnsey
- Department of Psychological Sciences, University of Connecticut, Storrs, CT, United States
| | - Zachary E Magin
- Department of Psychological Sciences, University of Connecticut, Storrs, CT, United States
| | - Weizi Wu
- School of Nursing, University of Connecticut, Storrs, CT, United States
| | - Joseph Fetta
- Department of Biobehavioral Nursing Science, College of Nursing, University of Florida, Gainesville, FL, United States
| | - Erik J Groessl
- Herbert Wertheim School of Public Health & Human Longevity Science, University of California San Diego, San Diego, CA, United States
- Veteran's Affairs San Diego Health System, San Diego, CA, United States
| | - Crystal Park
- Department of Psychological Sciences, University of Connecticut, Storrs, CT, United States
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Sas D, Gaudel F, Verdier D, Kolta A. Hyperexcitability of muscle spindle afferents in jaw-closing muscles in experimental myalgia: Evidence for large primary afferents involvement in chronic pain. Exp Physiol 2024; 109:100-111. [PMID: 38103003 PMCID: PMC10988680 DOI: 10.1113/ep090769] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Accepted: 11/30/2023] [Indexed: 12/17/2023]
Abstract
The goals of this review are to improve understanding of the aetiology of chronic muscle pain and identify new targets for treatments. Muscle pain is usually associated with trigger points in syndromes such as fibromyalgia and myofascial syndrome, and with small spots associated with spontaneous electrical activity that seems to emanate from fibers inside muscle spindles in EMG studies. These observations, added to the reports that large-diameter primary afferents, such as those innervating muscle spindles, become hyperexcitable and develop spontaneous ectopic firing in conditions leading to neuropathic pain, suggest that changes in excitability of these afferents might make an important contribution to the development of pathological pain. Here, we review evidence that the muscle spindle afferents (MSAs) of the jaw-closing muscles become hyperexcitable in a model of chronic orofacial myalgia. In these afferents, as in other large-diameter primary afferents in dorsal root ganglia, firing emerges from fast membrane potential oscillations that are supported by a persistent sodium current (INaP ) mediated by Na+ channels containing the α-subunit NaV 1.6. The current flowing through NaV 1.6 channels increases when the extracellular Ca2+ concentration decreases, and studies have shown that INaP -driven firing is increased by S100β, an astrocytic protein that chelates Ca2+ when released in the extracellular space. We review evidence of how astrocytes, which are known to be activated in pain conditions, might, through their regulation of extracellular Ca2+ , contribute to the generation of ectopic firing in MSAs. To explain how ectopic firing in MSAs might cause pain, we review evidence supporting the hypothesis that cross-talk between proprioceptive and nociceptive pathways might occur in the periphery, within the spindle capsule.
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Affiliation(s)
- Dar'ya Sas
- Département de NeurosciencesUniversité de MontréalMontréalQuébecCanada
- Centre Interdisciplinaire de Recherche sur le Cerveau et l'Apprentissage (CIRCA)MontréalQuébecCanada
| | - Fanny Gaudel
- Département de NeurosciencesUniversité de MontréalMontréalQuébecCanada
- Centre Interdisciplinaire de Recherche sur le Cerveau et l'Apprentissage (CIRCA)MontréalQuébecCanada
| | - Dorly Verdier
- Département de NeurosciencesUniversité de MontréalMontréalQuébecCanada
- Centre Interdisciplinaire de Recherche sur le Cerveau et l'Apprentissage (CIRCA)MontréalQuébecCanada
| | - Arlette Kolta
- Département de NeurosciencesUniversité de MontréalMontréalQuébecCanada
- Centre Interdisciplinaire de Recherche sur le Cerveau et l'Apprentissage (CIRCA)MontréalQuébecCanada
- Faculté de Médecine DentaireUniversité de MontréalMontréalQuébecCanada
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Hayashi K, Lesnak JB, Plumb AN, Rasmussen LA, Sluka KA. P2X7-NLRP3-Caspase-1 signaling mediates activity-induced muscle pain in male but not female mice. Pain 2023; 164:1860-1873. [PMID: 36930885 PMCID: PMC10363217 DOI: 10.1097/j.pain.0000000000002887] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 12/23/2022] [Indexed: 03/19/2023]
Abstract
ABSTRACT We developed an animal model of activity-induced muscle pain that is dependent on local macrophage activation and release of interleukin-1β (IL-1β). Activation of purinergic type 2X (P2X) 7 receptors recruits the NOD-like receptor protein (NLRP) 3 and activates Caspase-1 to release IL-1β. We hypothesized that pharmacological blockade of P2X7, NLRP3, and Caspase-1 would prevent development of activity-induced muscle pain in vivo and release of IL-1β from macrophages in vitro. The decrease in muscle withdrawal thresholds in male, but not female, mice was prevented by the administration of P2X7, NLRP3, and Caspase-1 inhibitors before induction of the model, whereas blockade of IL-1β before induction prevented muscle hyperalgesia in both male and female mice. Blockade of P2X7, NLRP3, Capsase-1, or IL-1β 24 hours, but not 1 week, after induction of the model alleviated muscle hyperalgesia in male, but not female, mice. mRNA expression of P2X7, NLRP3, Caspase-1, and IL-1β from muscle was increased 24 hours after induction of the model in both male and female mice. Using multiplex, increases in IL-1β induced by combining adenosine triphosphate with pH 6.5 in lipopolysaccharide-primed male and female macrophages were significantly lower with the presence of inhibitors of P2X7 (A740003), NLRP3 (MCC950), and Caspase-1 (Z-WEHD-FMK) when compared with the vehicle. The current data suggest the P2X7/NLRP3/Caspase-1 pathway contributed to activity-induced muscle pain initiation and early maintenance phases in male but not female, and not in late maintenance phases in male mice.
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Affiliation(s)
- Kazuhiro Hayashi
- Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, IA, USA
| | - Joseph B. Lesnak
- Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, IA, USA
| | - Ashley N. Plumb
- Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, IA, USA
| | - Lynn A. Rasmussen
- Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, IA, USA
| | - Kathleen A. Sluka
- Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, IA, USA
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Santos EJ, Giddings AN, Kandil FA, Negus SS. Climbing behavior by mice as an endpoint for preclinical assessment of drug effects in the absence and presence of pain. FRONTIERS IN PAIN RESEARCH 2023; 4:1150236. [PMID: 37139343 PMCID: PMC10149664 DOI: 10.3389/fpain.2023.1150236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 03/27/2023] [Indexed: 05/05/2023] Open
Abstract
This study evaluated climbing in mice as a tool to assess the expression and treatment of pain-related behavioral depression in male and female ICR mice. Mice were videotaped during 10-min sessions in a vertical plexiglass cylinder with wire mesh walls, and "Time Climbing" was scored by observers blind to treatments. Initial validation studies demonstrated that baseline climbing was stable across repeated days of testing and depressed by intraperitoneal injection of dilute lactic acid (IP acid) as an acute pain stimulus. Additionally, IP acid-induced depression of climbing was blocked by the positive-control non-steroidal anti-inflammatory drug (NSAID) ketoprofen but not by the negative control kappa opioid receptor agonist U69593. Subsequent studies examined effects of single-molecule opioids (fentanyl, buprenorphine, naltrexone) and of fixed-proportion fentanyl/naltrexone mixtures (10:1, 3.2:1, and 1:1) that vary in their efficacy at the mu opioid receptor (MOR). Opioids administered alone produced a dose- and efficacy-dependent decrease in climbing, and fentanyl/naltrexone-mixture data indicated that climbing in mice is especially sensitive to disruption by even low-efficacy MOR activation. Opioids administered as a pretreatment to IP acid failed to block IP acid-induced depression of climbing. Taken together, these findings support the utility of climbing in mice as an endpoint to evaluate candidate-analgesic effectiveness both to (a) produce undesirable behavioral disruption when the test drug is administered alone, and (b) produce a therapeutic blockade of pain-related behavioral depression. The failure of MOR agonists to block IP acid-induced depression of climbing likely reflects the high sensitivity of climbing to disruption by MOR agonists.
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Affiliation(s)
| | | | | | - S. Stevens Negus
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, United States
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Chiu HY, Su IW, Yu YW, Chen YC, Chen CC, Lin JH. Soreness or sng: a common symptom with differential clinical impact from pain in degenerative lumbar spine diseases. BMJ Open Qual 2023; 12:e001982. [PMID: 36690383 PMCID: PMC9872478 DOI: 10.1136/bmjoq-2022-001982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 01/06/2023] [Indexed: 01/25/2023] Open
Abstract
INTRODUCTION Soreness is a common complaint in patients who receive lumbar spine surgery (LSS) for degenerative lumbar spine diseases (DLSD). However, soreness is not assessed independently and its impacts on outcomes of LSS remains largely unknown. Sng(pronounced sә-ng, ) in Chinese language is the word with the closest meaning to soreness, and Chinese-speaking people naturally use sng to describe their non-pain 'soreness' symptom. This study was aimed to investigate the prevalence and impacts of soreness or sng on outcome of LSS by introducing Visual Analogue Scale (VAS) of sng on back and leg. MATERIALS AND METHODS This prospective cohort study recruited patients who receive LSS for DLSD. Participants completed the patient-reported outcome measures at 1 week before and 1 years after LSS. The patient-reported outcome measures included (1) VAS for back pain, leg pain, back sng and leg sng, (2) Oswestry Disability Index (ODI) and (3) RAND 36-item Short Form Health Survey. The minimal clinical important difference (MCID) of ODI and physical component health-related quality of life (HRQoL) was used. RESULTS A total of 258 consecutive patients were included and 50 dropped out at follow-up. Preoperatively, the prevalence of sng was comparable to pain both on back and leg; postoperatively, the prevalence of sng was higher than pain. Leg and back sng were associated with preoperative and postoperative mental HRQoL, respectively. The reduction of sng on back and leg were significantly less than pain postoperatively. Leg sng was the only symptom independently associated with attaining MCID. CONCLUSION Soreness or sng should be assessed independently from pain in patients receiving LSS for DLSD because soreness or sng had substantial clinical impacts on the outcome of LSS.
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Affiliation(s)
- Hsiao-Yen Chiu
- School of Nursing, Taipei Medical University, Taipei, Taiwan
- Department of Nursing, Taipei Medical University Hospital, Taipei, Taiwan
| | - I-Wen Su
- Neurobiology & Cognitive Science Center, National Taiwan University, Taipei, Taiwan
- Graduate Institute of Brain and Mind Sciences, National Taiwan University, Taipei City, Taiwan
- Graduate Institute of Linguistics, National Taiwan University, Taipei City, Taiwan
| | - Yu-Wen Yu
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
- Neuroscience research center, Taipei Medical University, Taipei, Taiwan
| | - Yi-Chen Chen
- Department of Neurosurgery, Taipei Medical University Hospital, Taipei, Taiwan
| | - Chih-Cheng Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
- Neuroscience research center, Taipei Medical University, Taipei, Taiwan
| | - Jiann-Her Lin
- Neuroscience research center, Taipei Medical University, Taipei, Taiwan
- Department of Neurosurgery, Taipei Medical University Hospital, Taipei, Taiwan
- Division of Neurosurgery, Department of Surgery, School of Medicine, Taipei Medical University, Taipei, Taiwan
- Taipei Neuroscience Institute, Taipei Medical University, Taipei, Taiwan
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Central Sensitization Is Associated with Inferior Patient-Reported Outcomes and Increased Osteotomy Site Pain in Patients Undergoing Medial Opening-Wedge High Tibial Osteotomy. MEDICINA (KAUNAS, LITHUANIA) 2022; 58:medicina58121752. [PMID: 36556954 PMCID: PMC9783071 DOI: 10.3390/medicina58121752] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 11/22/2022] [Accepted: 11/29/2022] [Indexed: 12/04/2022]
Abstract
Background and Objectives: Studies have shown that centrally sensitized patients have worse clinical outcomes following total knee arthroplasty (TKA) than non-centrally sensitized patients. It is unclear whether central sensitization (CS) affects patient-reported outcomes (PROs) and/or level of osteotomy site pain in patients undergoing medial opening-wedge high tibial osteotomy (MOWHTO). The purpose of this study was to determine whether CS is associated with PROs and osteotomy site pain following MOWHTO. Materials and Methods: A retrospective evaluation was conducted on 140 patients with varus knee osteoarthritis (OA) who were treated with MOWHTO and monitored for two years. Before surgery, the Central Sensitization Inventory (CSI) was used to assess CS status, and a CSI of 40 or higher was considered indicative of CS. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and pain visual analogue scale (VAS) were used to assess PROs. The minimal clinically important difference (MCID) for the WOMAC was set as 4.2 for the pain subscore, 1.9 for the stiffness subscore, 10.1 for the function subscore, and 16.1 for the total based on the results of a previous study. The WOMAC score, pain VAS score of the osteotomy site, and the achievement rates of WOMAC MCID were compared between the CS and non-CS groups. Results: Thirty-seven patients were assigned to the CS group, whereas 84 were assigned to the non-CS group. Before surgery, the CS group showed a higher WOMAC score than the non-CS group (58.7 vs. 49.4, p < 0.05). While there was a statistically significant improvement in WOMAC subscores (pain, stiffness, function, and total) for both groups at two years after surgery (all p < 0.05), the CS group had a higher WOMAC score than the non-CS group (37.1 vs. 21.8, p < 0.05). The CS group showed significantly inferior results in pre- and postoperative changes of WOMAC subscores (pain, function, and total) relative to the non-CS group (all p < 0.05). In addition, pain at the osteotomy site was more severe in the CS group than in the non-CS group at two years after surgery (4.8 vs. 2.2, p < 0.05). Patients with CS had worse MCID achievement rates across the board for WOMAC pain, function, and total scores (all p < 0.05) compared to the non-CS group. Conclusions: Centrally sensitized patients following MOWHTO had worse PROs and more severe osteotomy site pain compared to non-centrally sensitized patients. Furthermore, the WOMAC MCID achievement rate of patients with CS was lower than that of patients without CS. Therefore, appropriate preoperative counseling and perioperative pain management are necessary for patients with CS undergoing MOWHTO. Level of Evidence: Level III, case-control study.
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Mechanisms and manifestations in musculoskeletal pain: from experimental to clinical pain settings. Pain 2022; 163:S29-S45. [PMID: 35984370 DOI: 10.1097/j.pain.0000000000002690] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 05/09/2022] [Indexed: 01/18/2023]
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10
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Páez O, Segura-Chama P, Almanza A, Pellicer F, Mercado F. Properties and Differential Expression of H + Receptors in Dorsal Root Ganglia: Is a Labeled-Line Coding for Acid Nociception Possible? Front Physiol 2021; 12:733267. [PMID: 34764880 PMCID: PMC8576393 DOI: 10.3389/fphys.2021.733267] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 10/05/2021] [Indexed: 11/13/2022] Open
Abstract
Pain by chemical irritants is one of the less well-described aspects of nociception. The acidic substance is the paradigm of the chemical noxious compound. An acidic insult on cutaneous, subcutaneous and muscle tissue results in pain sensation. Acid (or H+) has at least two main receptor channels in dorsal root ganglia (DRG) nociceptors: the heat receptor transient receptor potential vanilloid 1 (TRPV1) and the acid-sensing ionic channels (ASICs). TRPV1 is a low-sensitivity H+ receptor, whereas ASIC channels display a higher H+ sensitivity of at least one order of magnitude. In this review, we first describe the functional and structural characteristics of these and other H+-receptor candidates and the biophysics of their responses to low pH. Additionally, we compile reports of the expression of these H+-receptors (and other possible complementary proteins) within the DRG and compare these data with mRNA expression profiles from single-cell sequencing datasets for ASIC3, ASIC1, transient receptor potential Ankiryn subtype 1 (TRPA1) and TRPV1. We show that few nociceptor subpopulations (discriminated by unbiased classifications) combine acid-sensitive channels. This comparative review is presented in light of the accumulating evidence for labeled-line coding for most noxious sensory stimuli.
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Affiliation(s)
- Omar Páez
- Laboratorio de Fisiología Celular, Dirección de Investigaciones en Nuerociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Ciudad de México, Mexico
| | - Pedro Segura-Chama
- Laboratorio de Fisiología Celular, Dirección de Investigaciones en Nuerociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Ciudad de México, Mexico
- Cátedras CONACyT, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Ciudad de México, Mexico
| | - Angélica Almanza
- Laboratorio de Fisiología Celular, Dirección de Investigaciones en Nuerociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Ciudad de México, Mexico
| | - Francisco Pellicer
- Laboratorio de Neurofisiología Integrativa, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Ciudad de México, Mexico
| | - Francisco Mercado
- Laboratorio de Fisiología Celular, Dirección de Investigaciones en Nuerociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Ciudad de México, Mexico
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Sinclair P, Kadhum M, Paton B. Tolerance to Intermittent vs. Continuous Blood Flow Restriction Training: A meta-Analysis. Int J Sports Med 2021; 43:3-10. [PMID: 34535020 DOI: 10.1055/a-1537-9886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The proven beneficial effects of low-load blood flow restriction training on strength gain has led to further exploration into its application during rehabilitation, where the traditional use of heavy loads may not be feasible. With current evidence showing that low-load blood flow restriction training may be less well tolerated than heavy-load resistance training, this review was conducted to decipher whether intermittently deflating the pressure cuff during rest intervals of a training session improves tolerance to exercise, without compromising strength. Four databases were searched for randomized controlled trials that compared the effect of intermittent versus continuous blood flow restriction training on outcomes of exercise tolerance or strength in adults. Nine studies were identified, with six included in the meta-analysis. No significant difference in rate of perceived exertion was found (SMD-0.06, 95% CI-0.41 to 0.29, p=0.73, I 2=80%). Subgroup analysis excluding studies that introduced bias showed a shift towards favoring the use of intermittent blood flow restriction training (SMD-0.42, 95% CI-0.87 to 0.03, p=0.07, I 2=0%). There was no significant difference in strength gain. Intermittent cuff deflations during training intervals does not improve tolerance to exercise during blood flow restriction training.
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Affiliation(s)
- Pierre Sinclair
- Department of Institute of Sports and Exercise Health (ISEH), University College London, London, United Kingdom of Great Britain and Northern Ireland
| | - Murtaza Kadhum
- Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences (NDORMS), University of Oxford, Oxford, United Kingdom of Great Britain and Northern Ireland
| | - Bruce Paton
- Department of Institute of Sports and Exercise Health (ISEH), University College London, London, United Kingdom of Great Britain and Northern Ireland
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12
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Palsson TS, Doménech-García V, Boudreau SS, Graven-Nielsen T. Pain referral area is reduced by remote pain. Eur J Pain 2021; 25:1804-1814. [PMID: 33987881 DOI: 10.1002/ejp.1792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 05/02/2021] [Indexed: 11/10/2022]
Abstract
BACKGROUND Endogenous pain inhibitory mechanisms are known to reduce pain intensity, but whether they influence the size and distribution of pain referral is unclear. This study aimed to determine if referred pain is reduced by applying a remote, conditioning painful stimulus. METHODS Twenty-four healthy men participated in this randomized, crossover study with a control and conditioning session. Referred pain was induced from the infraspinatus muscle (dominant side) by a painful pressure for 60 s. When applying pressure, the intensity was adjusted to a local pain intensity of 7/10 on a numerical rating scale. In the conditioning session, tonic painful pressure was simultaneously applied to the non-dominant leg during induction of referred pain. The area of referred pain was drawn onto a digital body chart and size extracted for data analysis. RESULTS For the total group and in a subgroup with distinct patterns of referred pain (n = 15/24), the pain area perceived in the back and front+back was smaller during the conditioning compared with the control (p < 0.05). No significant difference was found between sessions in a subgroup only demonstrating local pain (n = 9/24). CONCLUSIONS Engaging the descending noxious inhibitory control reduced the size of pain areas predominately when distinct pain referral was present. Assuming a conditioning effect of descending inhibitory control acting on dorsal horn neurons, these findings may indicate that mechanisms underlying pain referral can be modulated by endogenous control. The findings may indicate that referred pain may be a useful proxy to evaluate sensitivity of central pain mechanisms as previously suggested. SIGNIFICANCE The current results indicate a link between endogenous inhibition and pain referral. Descending inhibitory control effects on pain referral support a spinal mechanism involved in pain referral. Future studies should investigate whether the spatial characteristics of referred pain (e.g. size, frequency of affected body regions and distribution away from the primary nociceptive stimulus) can useful to evaluate the efficiency of endogenous pain modulation.
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Affiliation(s)
- Thorvaldur S Palsson
- Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Victor Doménech-García
- Department of Physiotherapy, Faculty of Health Sciences, Universidad San Jorge, Villanueva de Gállego, Zaragoza, Spain
| | - Shellie S Boudreau
- Center For Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Thomas Graven-Nielsen
- Center For Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
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13
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Fibromyalgia: Pathogenesis, Mechanisms, Diagnosis and Treatment Options Update. Int J Mol Sci 2021; 22:ijms22083891. [PMID: 33918736 PMCID: PMC8068842 DOI: 10.3390/ijms22083891] [Citation(s) in RCA: 194] [Impact Index Per Article: 64.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 04/06/2021] [Accepted: 04/07/2021] [Indexed: 12/13/2022] Open
Abstract
Fibromyalgia is a syndrome characterized by chronic and widespread musculoskeletal pain, often accompanied by other symptoms, such as fatigue, intestinal disorders and alterations in sleep and mood. It is estimated that two to eight percent of the world population is affected by fibromyalgia. From a medical point of view, this pathology still presents inexplicable aspects. It is known that fibromyalgia is caused by a central sensitization phenomenon characterized by the dysfunction of neuro-circuits, which involves the perception, transmission and processing of afferent nociceptive stimuli, with the prevalent manifestation of pain at the level of the locomotor system. In recent years, the pathogenesis of fibromyalgia has also been linked to other factors, such as inflammatory, immune, endocrine, genetic and psychosocial factors. A rheumatologist typically makes a diagnosis of fibromyalgia when the patient describes a history of pain spreading in all quadrants of the body for at least three months and when pain is caused by digital pressure in at least 11 out of 18 allogenic points, called tender points. Fibromyalgia does not involve organic damage, and several diagnostic approaches have been developed in recent years, including the analysis of genetic, epigenetic and serological biomarkers. Symptoms often begin after physical or emotional trauma, but in many cases, there appears to be no obvious trigger. Women are more prone to developing the disease than men. Unfortunately, the conventional medical therapies that target this pathology produce limited benefits. They remain largely pharmacological in nature and tend to treat the symptomatic aspects of various disorders reported by the patient. The statistics, however, highlight the fact that 90% of people with fibromyalgia also turn to complementary medicine to manage their symptoms.
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14
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Palsson TS, Boudreau SA, Ortiz Lucas M, Bravo Esteban-Herreros E, Garrigós-Pedrón M, Herrero P, Doménech-García V. The Area of Pressure-Induced Referred Pain Is Dependent on the Intensity of the Suprathreshold Stimulus: An Explorative Study. PAIN MEDICINE 2021; 22:663-669. [PMID: 33123739 DOI: 10.1093/pm/pnaa377] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE To investigate the pain referral area (number of pixels) and extent (vector length) as elicited from increasing intensities of pressure-induced pain at the shoulder. DESIGN Cross-sectional design. SETTING Clinical laboratory setting. PARTICIPANTS Twenty-two healthy men and women participated in two experimental sessions. METHODS Delayed onset of muscle soreness (DOMS) was induced in the dominant shoulder and assessed 24 hours later. Participants rated the level of DOMS on a 6-point Likert scale. Four different intensities (pressure pain threshold [PPT]+20%, PPT+30%, PPT+40%, and PPT+50%) were applied to the infraspinatus in a randomized, balanced fashion for 60 seconds from low to high intensity or vice versa. The resulting location, area, and extent of referred pain as drawn by the participants on a digital body chart were extracted and expressed in pixels. The extent of pain was defined as the vector length extending from the ipsilateral earlobe to the most distal location of the pain. RESULTS The referred pain area from PPT+20% was smaller than PPT+30%, PPT+40%, and PPT+50%. The extent of referred pain did not differ between the pressure pain intensities. CONCLUSIONS Pressure intensity at PPT+30%, but no more, produces the greatest referred pain area as compared with the traditional pressure intensity of PPT+20%. Thus, the intensity of PPT+30% may be ideal for exploring the mechanisms of referred pain. The extent of the pain represents an independent expression of the intensity of the provoking stimulus and may be more closely related to the location of the stimulus.
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Affiliation(s)
- Thorvaldur Skuli Palsson
- Department of Health Science and Technology, SMI, Faculty of Medicine, Aalborg University, Aalborg, Denmark
| | - Shellie Ann Boudreau
- Center for Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, SMI, Aalborg University, Aalborg, Denmark
| | | | - Elisabeth Bravo Esteban-Herreros
- Toledo Physiotherapy Research Group (GIFTO), E.U.E. Fisioterapia de Toledo, Universidad de Castilla la Mancha, Ciudad real, Spain
| | - Miriam Garrigós-Pedrón
- Departamento de Fisioterapia, Motion in Brains Research Group, Institute of Neuroscience and Sciences of the Movement (INCIMOV), Centro Superior de Estudios Universitarios La Salle, Universidad Autónoma de Madrid, Madrid, Spain.,Departamento de Ciencias Biomedicas, Facultad de Ciencias de la Salud, Universidad Cardenal Herrera-CEU, CEU Universities, Alfara del Patriarca, Valencia, Spain
| | - Pablo Herrero
- Faculty of Health Sciences, University of Zaragoza, Zaragoza, Spain
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15
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Ford B, Halaki M, Diong J, Ginn KA. Acute experimentally-induced pain replicates the distribution but not the quality or behaviour of clinical appendicular musculoskeletal pain. A systematic review. Scand J Pain 2020; 21:217-237. [PMID: 34387953 DOI: 10.1515/sjpain-2020-0076] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 10/16/2020] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Experimental pain is a commonly used method to draw conclusions about the motor response to clinical musculoskeletal pain. A systematic review was performed to determine if current models of acute experimental pain validly replicate the clinical experience of appendicular musculoskeletal pain with respect to the distribution and quality of pain and the pain response to provocation testing. METHODS A structured search of Medline, Scopus and Embase databases was conducted from database inception to August 2020 using the following key terms: "experimental muscle pain" OR "experimental pain" OR "pain induced" OR "induced pain" OR "muscle hyperalgesia" OR ("Pain model" AND "muscle"). Studies in English were included if investigators induced experimental musculoskeletal pain into a limb (including the sacroiliac joint) in humans, and if they measured and reported the distribution of pain, quality of pain or response to a provocation manoeuvre performed passively or actively. Studies were excluded if they involved prolonged or delayed experimental pain, if temporomandibular, orofacial, lumbar, thoracic or cervical spine pain were investigated, if a full text of the study was not available or if they were systematic reviews. Two investigators independently screened each title and abstract and each full text paper to determine inclusion in the review. Disagreements were resolved by consensus with a third investigator. RESULTS Data from 57 experimental pain studies were included in this review. Forty-six of these studies reported pain distribution, 41 reported pain quality and six detailed the pain response to provocation testing. Hypertonic saline injection was the most common mechanism used to induce pain with 43 studies employing this method. The next most common methods were capsaicin injection (5 studies) and electrical stimulation, injection of acidic solution and ischaemia with three studies each. The distribution of experimental pain was similar to the area of pain reported in clinical appendicular musculoskeletal conditions. The quality of appendicular musculoskeletal pain was not replicated with the affective component of the McGill Pain Questionnaire consistently lower than that typically reported by musculoskeletal pain patients. The response to provocation testing was rarely investigated following experimental pain induction. Based on the limited available data, the increase in pain experienced in clinical populations during provocative maneuvers was not consistently replicated. CONCLUSIONS Current acute experimental pain models replicate the distribution but not the quality of chronic clinical appendicular musculoskeletal pain. Limited evidence also indicates that experimentally induced acute pain does not consistently increase with tests known to provoke pain in patients with appendicular musculoskeletal pain. The results of this review question the validity of conclusions drawn from acute experimental pain studies regarding changes in muscle behaviour in response to pain in the clinical setting.
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Affiliation(s)
- Brendon Ford
- Faculty of Medicine and Health, School of Medical Sciences, The University of Sydney, Sydney, NSW Australia
| | - Mark Halaki
- Faculty of Medicine and Health, School of Health Sciences, The University of Sydney, Sydney, NSWAustralia
| | - Joanna Diong
- Faculty of Medicine and Health, School of Medical Sciences, The University of Sydney, Sydney, NSW Australia
| | - Karen A Ginn
- Faculty of Medicine and Health, School of Medical Sciences, The University of Sydney, Sydney, NSW Australia
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16
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Wang D, Merkle SL, Lee JE, Sluka KA, Rakel B, Graven-Nielsen T, Frey-Law LA. Multisensory Sensitivity is Related to Deep-Tissue but Not Cutaneous Pain Sensitivity in Healthy Individuals. J Pain Res 2020; 13:2493-2508. [PMID: 33116791 PMCID: PMC7548328 DOI: 10.2147/jpr.s267972] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 08/29/2020] [Indexed: 12/18/2022] Open
Abstract
PURPOSE Some individuals with chronic pain find daily life sensations (eg, noise, light, or touch) aversive. This amplification of multisensory sensations has been associated with centrally mediated plasticity; for example, greater multisensory sensitivity (MSS) occurs in patients with fibromyalgia than rheumatoid arthritis. However, whether MSS preferentially relates to pain measures which reflect central influences (eg, dynamic quantitative sensory testing (QST) or referred pain), or whether the MSS-pain relationship requires priming from chronic pain, is unknown. Thus, this cross-sectional study investigated the relationships between MSS assessed in a pain-free state and evoked pain sensitivity. METHODS Experimental intramuscular infusion pain and multiple static and dynamic QST were assessed in 465 healthy, pain-free adults: pain thresholds using pressure (PPTs) and heat (HPTs), temporal summation of pain (TSP) using pressure, heat or punctate stimuli, and conditioned pain modulation (CPM) using pressure or heat test stimuli. MSS was assessed using 7 items from Barsky's Somatosensory Amplification Scale. Differences in pain and QST between sex-specific MSS quartiles were assessed, adjusting for multiple comparisons. All participants completed at least one intramuscular infusion condition, but not all were asked to complete each QST (n=166-465). RESULTS Both static and dynamic QST differed between highest and lowest MSS quartiles using pressure stimuli: lower PPTs (adjusted-p<0.01); increased pressure TSP (adjusted-p=0.02); lower pressure CPM (adjusted-p=0.01). However, none of the heat or punctate QST measures (HPTs, TSP, or CPM) differed between MSS quartiles (adjusted-p>0.05). Odds of experiencing TSP or referred pain was not greater, whereas CPM was 8-fold less likely, in those with highest MSS. CONCLUSION Normal variation in non-noxious MSS is related to both static and dynamic pain sensitivity, without sensitization associated with chronic pain, but is dependent on the QST stimulus. Thus, common influences on MSS and pain sensitivity may involve central mechanisms but are likely more complex than previously recognized.
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Affiliation(s)
- Dan Wang
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Shannon L Merkle
- United States Army Research Institute of Environmental Medicine (USARIEM), Natick, MA, USA
| | - Jennifer E Lee
- Department of Psychology, Mount Mercy University, Cedar Rapids, IA, USA
- College of Nursing, University of Iowa, Iowa City, IA, USA
| | - Kathleen A Sluka
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Barbara Rakel
- College of Nursing, University of Iowa, Iowa City, IA, USA
| | - Thomas Graven-Nielsen
- Center for Neuroplasticity and Pain (CNAP), SMI, Aalborg University, Aalborg, Denmark
| | - Laura A Frey-Law
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
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17
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Dunn JS, Nagi SS, Mahns DA. Minocycline reduces experimental muscle hyperalgesia induced by repeated nerve growth factor injections in humans: A placebo‐controlled double‐blind drug‐crossover study. Eur J Pain 2020; 24:1138-1150. [DOI: 10.1002/ejp.1558] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 01/28/2020] [Accepted: 03/11/2020] [Indexed: 11/09/2022]
Affiliation(s)
- James S. Dunn
- School of Medicine Western Sydney University Penrith NSW Australia
| | - Saad S. Nagi
- School of Medicine Western Sydney University Penrith NSW Australia
- Department of Biomedical and Clinical Sciences Center for Social and Affective Neuroscience Linköping University Linköping Sweden
| | - David A. Mahns
- School of Medicine Western Sydney University Penrith NSW Australia
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18
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Merrells RJ, Cripps AJ, Chivers PT, Fournier PA. Role of lactic acidosis as a mediator of sprint-mediated nausea. Physiol Rep 2019; 7:e14283. [PMID: 31724342 PMCID: PMC6854110 DOI: 10.14814/phy2.14283] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
This study aims to determine whether there is a relationship between nausea level and lactic acidosis during recovery from sprinting. In all, 13 recreationally active males completed a 60 s bout of maximal intensity cycling. Prior to and for 45 min following exercise, blood pH, pCO2 , and lactate levels were measured together with nausea. In response to sprinting, nausea, lactate, and H+ concentrations increased and remained elevated for at least 10 min (p < .001), whereas pCO2 increased only transiently (p < .001) before falling below pre-exercise levels (p < .001), with all these variables returning toward pre-exercise levels during recovery. Both measures of nausea adopted for analyses (nausea profile, NP; visual analogue scale, VAS), demonstrated significant repeated measures correlation (rmcorr) post-exercise between nausea and plasma lactate (VAS and NPrrm > 0.595, p < .0001) and H+ concentrations (VAS and NPrrm > 0.689, p < .0001), but an inconsistent relationship with pCO2 (VAS rrm = 0.250, p = .040; NP rrm = 0.144, p = .248) and bicarbonate levels (VAS rrm = -0.252, p = .095; NP rrm = -0.397, p = .008). Linear mixed modeling was used to predict the trajectory of nausea over time, with both lactate and H+ concentrations found to be key predictors of nausea (p < .0001). In conclusion, this study reveals a strong positive relationship between nausea and both H+ and lactate concentrations during recovery from sprinting, a finding consistent with H+ and lactate being potential mediators of nausea post-sprinting. However, as the timing of the recovery of both H+ and lactate was delayed, compared to that of nausea, further research is required to confirm these findings and investigate other potential mechanisms.
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Affiliation(s)
- Robert J. Merrells
- School of Human SciencesDivision Sport Science, Exercise and HealthUniversity of Western AustraliaCrawleyAustralia
- School of Health SciencesThe University of Notre Dame AustraliaFremantleAustralia
| | - Ashley J. Cripps
- School of Health SciencesThe University of Notre Dame AustraliaFremantleAustralia
| | - Paola T. Chivers
- Institute for Health ResearchThe University of Notre Dame AustraliaFremantleAustralia
- Exercise Medicine Research Institute & School of Medical and Health SciencesEdith Cowan UniversityJoondalupAustralia
| | - Paul A. Fournier
- School of Human SciencesDivision Sport Science, Exercise and HealthUniversity of Western AustraliaCrawleyAustralia
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19
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Louca Jounger S, Eriksson N, Lindskog H, Oscarsson A, Simonsson V, Ernberg M, Christidis N. Repeated buffered acidic saline infusion in the human masseter muscle as a putative experimental pain model. Sci Rep 2019; 9:15474. [PMID: 31664156 PMCID: PMC6820748 DOI: 10.1038/s41598-019-51670-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 10/04/2019] [Indexed: 12/20/2022] Open
Abstract
This study investigated if repeated buffered acidic saline infusions into the masseter muscles induced muscle pain and mechanical sensitization. Fourteen healthy men participated in this double-blind, randomized, and placebo-controlled study. Two repeated infusions (day 1 and 3) were given in the masseter muscles with either a buffered acidic saline solution (pH 5.2) or an isotonic saline solution (pH 6) as control. After 10 days of wash-out, the experiment was repeated with the other substance. Pressure pain thresholds (PPT), pain intensity, maximum unassisted mouth opening (MUO), and pain drawings were assessed before, directly following, and after each infusion at 5, 15, and 30 min and on day 4 and 7. Fatigue and pain intensity were assessed after a one-minute chewing test 30 min after infusions and day 4 and 7. Acidic saline induced higher pain intensity than control day 3 up to 5 min after infusions, but did not affect PPT. The chewing test did not evoke higher fatigue during chewing or MUO or after acidic saline infusion compared to control. Repeated acidic saline infusions in the masseter muscles induced a short-lasting muscle pain without mechanical hyperalgesia or functional pain. Hence, this model might not be superior to already existing experimental muscle pain models.
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Affiliation(s)
- Sofia Louca Jounger
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, SE-141 04, Huddinge, Sweden. .,Scandinavian Center for Orofacial Neurosciences (SCON), Huddinge, Sweden.
| | - Niklas Eriksson
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, SE-141 04, Huddinge, Sweden
| | - Helena Lindskog
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, SE-141 04, Huddinge, Sweden
| | - Anna Oscarsson
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, SE-141 04, Huddinge, Sweden
| | - Vivian Simonsson
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, SE-141 04, Huddinge, Sweden
| | - Malin Ernberg
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, SE-141 04, Huddinge, Sweden.,Scandinavian Center for Orofacial Neurosciences (SCON), Huddinge, Sweden
| | - Nikolaos Christidis
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, SE-141 04, Huddinge, Sweden.,Scandinavian Center for Orofacial Neurosciences (SCON), Huddinge, Sweden
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20
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Lesnak J, Sluka KA. Chronic non-inflammatory muscle pain: central and peripheral mediators. CURRENT OPINION IN PHYSIOLOGY 2019; 11:67-74. [PMID: 31998857 PMCID: PMC6988739 DOI: 10.1016/j.cophys.2019.06.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Conditions with chronic widespread non-inflammatory muscle pain, such as fibromyalgia, have complex etiologies with numerous proposed mechanisms for their pathophysiology of underlying chronic pain. Advancements in neuroimaging have allowed for the study of brain function and connectivity in humans with these conditions, while development of animal models have allowed for the study of both peripheral and central factors that lead to chronic pain. This article reviews the current literature surrounding the pathophysiology of chronic widespread non-inflammatory muscle pain focusing on both peripheral and central nervous system, as well as immune system, contributions to the development and maintenance of pain. A better understanding of the mechanisms underlying these conditions can allow for improvements in patient education, treatment and outcomes.
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Affiliation(s)
- Joseph Lesnak
- Department of Physical Therapy and Rehabilitation Science, Pain Research Program, 1-242 MEB, University of Iowa, Iowa City, IA 52252, USA
| | - Kathleen A. Sluka
- Department of Physical Therapy and Rehabilitation Science, Pain Research Program, 1-242 MEB, University of Iowa, Iowa City, IA 52252, USA
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21
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da Silva JCG, Silva KF, Domingos-Gomes JR, Batista GR, da Silva Freitas ED, Torres VBC, do Socorro Cirilo-Sousa M. Aerobic exercise with blood flow restriction affects mood state in a similar fashion to high intensity interval exercise. Physiol Behav 2019; 211:112677. [PMID: 31499050 DOI: 10.1016/j.physbeh.2019.112677] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 08/25/2019] [Accepted: 09/05/2019] [Indexed: 11/19/2022]
Abstract
We investigated the acute effects of aerobic exercise with blood flow restriction (BFR) on mood state in American football athletes. Twenty-two male American football athletes were randomly assigned to three experimental conditions: 1) aerobic exercise (AE: 40% VO2max), 2) aerobic exercise with BRF (AE + BFR: 40% VO2 max), and 3) high-intensity interval exercise (HIIE: 80% and 40% VO2max during exercise and the active intervals, respectively). Mood state and total mood disturbance (TMD) were assessed before, immediately post, and 1 h post-exerciser. Ratings of perceived exertion (RPE) were measured 30 min post-exercise. AE + BFR and HIIE significantly (p < 0.05) increased fatigue and tension compared to baseline immediately post-exercise, whereas vigor significantly (p < 0.05) decreased at the same time point for both conditions. TMD increased significantly (p < 0.05) for AE + BFR and HIIE immediately post-exercise and it remained elevated up to 1 h post-exercise for AE + BFR. AE did not significantly (p > 0.05) affect mood state or TMD and it was significantly (p < 0.05) lower than AE + BFR and HIIE. AE + BFR and HIIE also elicited significantly (p < 0.05) greater RPE levels than AE 30 min post-exercise. Therefore, AE + BFR induces acute impairments in mood state and RPE levels in a similar fashion to HIIE.
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Affiliation(s)
- Julio Cesar Gomes da Silva
- Department of Physical Education, Associate Graduate Program in Physical Education UPE/UFPB, João Pessoa, Paraíba, Brazil; Coordination of Physical Education/Professional Master's in Family Health, Nursing and Medical Schools, (FAMENE/FACENE), João Pessoa, Nova Esperança, Paraíba, Brazil; Coordination of Physical Education, Center for Higher Education and Development (CESED/UNIFACISA/FCM/ESAC), Campina Grande, Paraíba, Brazil.
| | - Kalinne Fernandes Silva
- Department of Physical Education, Associate Graduate Program in Physical Education UPE/UFPB, João Pessoa, Paraíba, Brazil
| | - Jarbas Ralison Domingos-Gomes
- Department of Physical Education, Associate Graduate Program in Physical Education UPE/UFPB, João Pessoa, Paraíba, Brazil
| | - Gilmário Ricarte Batista
- Department of Physical Education, Associate Graduate Program in Physical Education UPE/UFPB, João Pessoa, Paraíba, Brazil
| | | | - Vitor Bruno Cavalcanti Torres
- Department of Physical Education, Associate Graduate Program in Physical Education UPE/UFPB, João Pessoa, Paraíba, Brazil; Coordination of Physical Education, Center for Higher Education and Development (CESED/UNIFACISA/FCM/ESAC), Campina Grande, Paraíba, Brazil
| | - Maria do Socorro Cirilo-Sousa
- Department of Physical Education, Associate Graduate Program in Physical Education UPE/UFPB, João Pessoa, Paraíba, Brazil
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22
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Sørensen LB, Gazerani P, Graven-Nielsen T. Nerve growth factor-induced muscle hyperalgesia facilitates ischaemic contraction-evoked pain. Eur J Pain 2019; 23:1814-1825. [PMID: 31314952 DOI: 10.1002/ejp.1455] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 07/01/2019] [Accepted: 07/10/2019] [Indexed: 02/03/2023]
Abstract
BACKGROUND Intramuscular injection of Nerve Growth Factor (NGF) may influence the responsiveness of active chemo-sensitive channels affecting muscle pain sensitivity. This double-blinded crossover study in healthy humans assessed contraction-evoked pain responses and pain sensitivity during acute ischaemia in the tibialis anterior (TA) muscle before and 24 hr after five distributed NGF injections (1 µg, 4 cm interval) compared with control injections (isotonic-saline). METHODS Twenty-one subjects participated in two experimental phases, each including five sessions over 7 days, with a gap of 4 weeks in-between. Muscle pain intensity evoked with daily functional tasks (Likert scale score) was collected using a paper diary. Pain intensity evoked by ischaemic and non-ischaemic contractions numerical rating scale (NRS) was collected at Day0 and Day1. Pressure pain thresholds (PPTs) on the TA were recorded before (Day0), 3 hr, 1, 3, and 7 days post-injection, and after the ischaemic-contractions and post-cuff deflation at Day0 and Day1. RESULTS Increased Likert scores of pain were present for 7 days after NGF compared to control injections (p < .05). Higher NRS pain scores of ischaemic-contractions were seen when contracting the muscle injected with NGF compared to baseline (p = .003) and control (p = .012). Pain during non-ischaemic contractions was not significantly affected by NGF injections. Decreased PPTs were found at 3 hr, Day1 and Day3 post-injection (p < .05) in both conditions. Compared with pre-contractions, PPTs were increased following ischaemic contractions at Day0 (p < .05) and Day1 (p < .05) in both conditions. CONCLUSION This study showed that ischaemic contraction-evoked pain was facilitated in an NGF-sensitized muscle. SIGNIFICANCE Acidification of the muscle environment may affect muscle nociceptors and pain by different mechanisms, including activation of ASIC3 and TRPV1. In this study, pain evoked following ischaemic contractions was increased in the Nerve Growth Factor (NGF)-sensitized muscle compared with non-ischaemic contractions and in the non-sensitized muscle. These findings illustrate that responses of peripheral afferents under ischaemic conditions are altered by a pre-sensitized muscle. This highlights the role of growth factors, including NGF, in peripheral muscle sensitization with clinical implications for ischaemic myalgia.
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Affiliation(s)
- Line Bay Sørensen
- Center for Neuroplasticity and Pain (CNAP), SMI, Faculty of Medicine, Aalborg University, Aalborg, Denmark
| | - Parisa Gazerani
- Biomedicine, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark
| | - Thomas Graven-Nielsen
- Center for Neuroplasticity and Pain (CNAP), SMI, Faculty of Medicine, Aalborg University, Aalborg, Denmark
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Noreña AJ, Fournier P, Londero A, Ponsot D, Charpentier N. An Integrative Model Accounting for the Symptom Cluster Triggered After an Acoustic Shock. Trends Hear 2019; 22:2331216518801725. [PMID: 30249168 PMCID: PMC6156190 DOI: 10.1177/2331216518801725] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Acoustic shocks and traumas sometimes result in a cluster of debilitating symptoms, including tinnitus, hyperacusis, ear fullness and tension, dizziness, and pain in and outside the ear. The mechanisms underlying this large variety of symptoms remain elusive. In this article, we elaborate on the hypothesis that the tensor tympani muscle (TTM), the trigeminal nerve (TGN), and the trigeminal cervical complex (TCC) play a central role in generating these symptoms. We argue that TTM overuse (due to the acoustic shock), TTM overload (due to muscle tension), and ultimately, TTM injury (due to hypoxia and "energy crisis") lead to inflammation, thereby activating the TGN, TCC, and cortex. The TCC is a crossroad structure integrating sensory inputs coming from the head-neck complex (including the middle ear) and projecting back to it. The multimodal integration of the TCC may then account for referred pain outside the ear when the middle ear is inflamed and activates the TGN. We believe that our model proposes a synthetic and explanatory framework to explain the phenomena occurring postacoustic shock and potentially also after other nonauditory causes. Indeed, due to the bidirectional properties of the TCC, musculoskeletal disorders in the region of the head-neck complex, including neck injury due to whiplash or temporomandibular disorders, may impact the middle ear, thereby leading to otic symptoms. This previously unavailable model type is experimentally testable and must be taken as a starting point for identifying the mechanisms responsible for this particular subtype of tinnitus and its associated symptoms.
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Affiliation(s)
- Arnaud J Noreña
- 1 Aix-Marseille Université, UMR CNRS 7260, Laboratoire Neurosciences Intégratives et Adaptatives-Centre Saint-Charles, Marseille, France
| | - Philippe Fournier
- 1 Aix-Marseille Université, UMR CNRS 7260, Laboratoire Neurosciences Intégratives et Adaptatives-Centre Saint-Charles, Marseille, France
| | - Alain Londero
- 2 Service ORL et CCF, Hôpital Européen G. Pompidou, Paris, France
| | - Damien Ponsot
- 3 Académie de Lyon-Lycée Germaine Tillion, Sain-Bel, France
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Gregory NS, Gautam M, Benson CJ, Sluka KA. Acid Sensing Ion Channel 1a (ASIC1a) Mediates Activity-induced Pain by Modulation of Heteromeric ASIC Channel Kinetics. Neuroscience 2018; 386:166-174. [PMID: 29964154 DOI: 10.1016/j.neuroscience.2018.06.033] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 06/15/2018] [Accepted: 06/19/2018] [Indexed: 12/20/2022]
Abstract
Chronic muscle pain is acutely worsened by exercise. Acid sensing ion channels (ASIC) are heteromeric channels expressed in muscle sensory neurons that detect decreases in pH. We have previously shown ASIC3 is important in activity-induced hyperalgesia. However, ASICs form heteromers with ASIC1a being a key component in sensory neurons. Therefore, we studied the role of ASIC1a in mice using behavioral pharmacology and genetic deletion in a model of activity-induced hyperalgesia. We found ASIC1a-/- mice developed mechanical hyperalgesia similar to wild-type mice, but antagonism of ASIC1a, with psalmotoxin, prevented development of mechanical hyperalgesia in wild-type mice, but not in ASIC1a-/- mice. To explain this discrepancy, we then performed electrophysiology studies of ASICs and examined the effects of psalmotoxin on ASIC heteromers. We expressed ASIC1a, 2 and 3 heteromers or ASIC1 and 3 heteromers in CHO cells, and examined the effects of psalmotoxin on pH sensitivity. Psalmotoxin significantly altered the properties of ASIC hetomeric channels. Specifically, in ASIC1a/2/3 heteromers, psalmotoxin slowed the kinetics of desensitization, slowed the recovery from desensitization, and inhibited pH-dependent steady-state desensitization, but had no effect on pH-evoked current amplitudes. We found a different pattern in ASIC1a/3 heteromers. There was a significant leftward shift in the pH dose response of steady-state desensitization and decrease in pH-evoked current amplitudes. These results suggest that blockade of ASIC1a modulates the kinetics of heteromeric ASICs to prevent development of activity-induced hyperalgesia. These data suggest ASIC1a is a key subunit in heteromeric ASICs and may be a pharmacological target for treatment of musculoskeletal pain.
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Affiliation(s)
- Nicholas S Gregory
- Department of Physical Therapy and Rehabilitation Science, The University of Iowa, Iowa City, IA 52242, United States; Department of Neuroscience, The University of Iowa, Iowa City, IA 52242, United States; Pain Research Program, The University of Iowa, Iowa City, IA 52242, United States
| | - Mamta Gautam
- Department of Internal Medicine, The University of Iowa, Iowa City, IA 52242, United States; Pain Research Program, The University of Iowa, Iowa City, IA 52242, United States; Veterans Medical Center, Iowa City, IA, United States
| | - Christopher J Benson
- Department of Neuroscience, The University of Iowa, Iowa City, IA 52242, United States; Department of Internal Medicine, The University of Iowa, Iowa City, IA 52242, United States; Pain Research Program, The University of Iowa, Iowa City, IA 52242, United States; Veterans Medical Center, Iowa City, IA, United States
| | - Kathleen A Sluka
- Department of Physical Therapy and Rehabilitation Science, The University of Iowa, Iowa City, IA 52242, United States; Department of Neuroscience, The University of Iowa, Iowa City, IA 52242, United States; Pain Research Program, The University of Iowa, Iowa City, IA 52242, United States.
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25
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James G, Sluka KA, Blomster L, Hall L, Schmid AB, Shu CC, Little CB, Melrose J, Hodges PW. Macrophage polarization contributes to local inflammation and structural change in the multifidus muscle after intervertebral disc injury. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2018; 27:1744-1756. [PMID: 29948327 DOI: 10.1007/s00586-018-5652-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Revised: 05/13/2018] [Accepted: 06/01/2018] [Indexed: 12/19/2022]
Abstract
PURPOSE Intervertebral disk (IVD) lesion and its subsequent degeneration have a profound effect on the multifidus muscle. The subacute/early chronic phase of multifidus remodeling after IVD lesion has been proposed to be regulated by inflammatory processes. The balance between pro-inflammatory (M1) and anti-inflammatory (M2) macrophages plays an important role in maintaining tissue integrity after injury. The localization, polarization of macrophage subtypes and their mediation of the pro-inflammatory cytokine tumor necrosis factor (TNF) are unknown in paraspinal muscles during IVD degeneration. A sheep model of IVD degeneration was used to investigate the role of macrophages and TNF in the structural alterations that occur within the multifidus muscle. METHODS Anterolateral lesions were induced at L3-4 IVD in sheep. Multifidus muscle tissue at L4 was harvested 3 and 6 months after lesion and used for immunofluorescence assays to examine total macrophage number, macrophage polarization between M1 and M2, and to assess the localization of TNF expression in muscle, adipose and connective tissues from injured and naïve control animals. RESULTS A greater proportion of M1 macrophages is present in muscle at both 3 and 6 months after IVD lesion, and adipose tissue at 6 months. Total number of macrophages is unchanged. At 6 months, expression of TNF is increased in adipose and connective tissue and the proportion of TNF expressed by M1 macrophages is increased. CONCLUSIONS These data support the proposal that macrophages and TNF (pro-inflammatory cytokine) play an active role in the subacute/early chronic phase of remodeling in muscle, adipose and connective tissues of the multifidus during IVD degeneration. This presents a novel target for treatment. These slides can be retrieved under Electronic Supplementary Material.
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Affiliation(s)
- Gregory James
- Centre of Clinical Research Excellence in Spinal Pain, Injury and Health, School of Health and Rehabilitation Sciences, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Kathleen A Sluka
- Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, IA, USA
| | - Linda Blomster
- Centre of Clinical Research Excellence in Spinal Pain, Injury and Health, School of Health and Rehabilitation Sciences, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Leanne Hall
- Centre of Clinical Research Excellence in Spinal Pain, Injury and Health, School of Health and Rehabilitation Sciences, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Annina B Schmid
- Centre of Clinical Research Excellence in Spinal Pain, Injury and Health, School of Health and Rehabilitation Sciences, University of Queensland, Brisbane, QLD, 4072, Australia.,Nuffield Department of Clinical Neurosciences, Oxford University, Oxford, UK
| | - Cindy C Shu
- Raymond Purves Bone and Joint Research Laboratories, Kolling Institute of Medical Research, Institute of Bone and Joint Research, The Royal North Shore Hospital, University of Sydney, St Leonards, NSW, Australia
| | - Christopher B Little
- Raymond Purves Bone and Joint Research Laboratories, Kolling Institute of Medical Research, Institute of Bone and Joint Research, The Royal North Shore Hospital, University of Sydney, St Leonards, NSW, Australia
| | - James Melrose
- Raymond Purves Bone and Joint Research Laboratories, Kolling Institute of Medical Research, Institute of Bone and Joint Research, The Royal North Shore Hospital, University of Sydney, St Leonards, NSW, Australia.,Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Australia
| | - Paul W Hodges
- Centre of Clinical Research Excellence in Spinal Pain, Injury and Health, School of Health and Rehabilitation Sciences, University of Queensland, Brisbane, QLD, 4072, Australia.
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26
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Gazerani P, Cairns BE. Activation of rat masticatory muscle afferent fibres by acidic pH. Somatosens Mot Res 2018; 35:86-94. [PMID: 29848210 DOI: 10.1080/08990220.2018.1473246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
Previous research findings have suggested an important role for acid sensing ion channels (ASICs) in muscle pain mechanisms. This study was conducted to determine if masticatory muscle afferent fibres express ASICs, if there are sex differences in this expression, and to compare the effects of low pH and hypertonic saline on afferent fibres that innervate the masticatory muscle in vivo. Immunohistochemistry methods were applied to examine the expression of ASICs in trigeminal ganglion neurons, while in vivo electrophysiology techniques were employed to examine changes in masticatory muscle afferent fibre excitability. Both ASIC1 and ASIC3 were expressed by predominantly larger masticatory muscle ganglion neurons, but the frequency of ASIC3 expression (56%) was significantly greater than ASIC1 (35%). No sex-related differences in expression were identified. Injection of pH 5.8, but not pH 6.8, phosphate buffered saline evoked afferent discharges that were significantly greater than those evoked by pH 7.4 buffer (control). Since ASIC3 channels are not activated until the pH is around 6, these results indicate that activation of both channels contributes to excitation of masticatory muscle afferent fibres. The results further show that many masticatory muscle afferent fibres, which respond to low pH, are low threshold mechanoreceptors. These findings may explain why injection of low pH solutions into the masticatory muscles of healthy humans is not associated with significant muscle pain.
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Affiliation(s)
- Parisa Gazerani
- a Department of Health Science and Technology, Faculty of Medicine , Aalborg University , Aalborg East , Denmark
| | - Brian Edwin Cairns
- a Department of Health Science and Technology, Faculty of Medicine , Aalborg University , Aalborg East , Denmark.,b Faculty of Pharmaceutical Sciences , The University of British Columbia , Vancouver , Canada
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27
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Exploration of Quantitative Sensory Testing in Latent Trigger Points and Referred Pain Areas. Clin J Pain 2018; 34:409-414. [DOI: 10.1097/ajp.0000000000000560] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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28
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Acid-induced experimental knee pain and hyperalgesia in healthy humans. Exp Brain Res 2017; 236:587-598. [PMID: 29250706 DOI: 10.1007/s00221-017-5155-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 12/14/2017] [Indexed: 01/08/2023]
Abstract
Inflammation and the related acidity in peri-articular structures may be involved in pain generation and hyperalgesia in knee osteoarthritis. This study investigated pain and associated hyperalgesia provoked by infusion of acidic saline into the infrapatellar fat pad. Twenty-eight subjects participated in two sessions in which acidic saline (AS, pH 5) or neutral saline (NS, pH 7.4) were infused into the infrapatellar fat pad for 15 min. Pain intensity, pain area, mechanical and thermal sensitivity, and maximal voluntary knee extension force were recorded. Repeated infusions were performed in 14 subjects. Infusion of AS caused significantly higher pain intensity, larger pain areas, induced hyperalgesia around the infused knee, and reduced extension force. No significant pain facilitation or spreading of hyperalgesia was found after repeated infusions as compared with single infusions. Acidic saline infused into the infrapatellar fat pad provoked pain and localized mechanical hyperalgesia. Thus, this acid-induced pain model may mimic the early-stage responses to tissue injury of knee osteoarthritis.
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29
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Wang K, Luo Y, Asaki T, Graven-Nielsen T, Cairns BE, Arendt-Nielsen T, Arendt-Nielsen L. Acid-induced experimental muscle pain and hyperalgesia with single and repeated infusion in human forearm. Scand J Pain 2017; 17:260-266. [DOI: 10.1016/j.sjpain.2017.07.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 06/19/2017] [Accepted: 07/05/2017] [Indexed: 11/17/2022]
Abstract
Abstract
Background and purpose
Acid has long been thought to play an important role in the pain process. Animal study showed that repeated acid stimulation induced central sensitization. The purpose of the study is to investigate muscle pain and hyperalgesia evoked byintramuscular infusion of saline at different pH levels, and to compare the effect of a single versus repeated acid infusions.
Methods
Twenty healthy subjects received infusions of buffered saline (pH 5.0, 6.0, and 7.4) into the brachioradialis muscle in a randomized order. Twelve of the subjects received repeated infusions. The subjects rated the pain intensity on visual analogue scale (VAS). Thermal pain sensitivity, and pressure pain threshold (PPT) were assessed in both arm before, during, immediately after, one hour after, and one day after the infusion. A McGill Pain Questionnaire and pain mapping were completed after each infusion.
Results
The pH 5 solution caused significantly higher pain and larger areas than pH 6.0 or 7.4. The local PPTs were significantly decreased (hyperalgesia) during and immediately after infusion of all three solutions. No significant differences were detected between the first and second infusion.
Conclusions
The intensity of acid-induced muscle pain is pH-dependent. All three solutions induced pressure hyperalgesia at the infusion site. Repeated infusions did not induce increased pain or prolonged hyperalgesia as compared with a single injection. Human intramuscular acidic saline infusion could not produce chronic pain model.
Implications
The acid-induced pain model may reflect the early stage responses to tissue injury of clinical conditions. Repeated intramuscular acidic saline injection model of prolonged hyperalgesia in rodents could not be translated into a human for modelling chronic musculoskeletal pain.
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Affiliation(s)
- Kelun Wang
- SMI , Department of Health Science and Technology, Faculty of Medicine , Aalborg University , Aalborg , Denmark
| | - Yi Luo
- SMI , Department of Health Science and Technology, Faculty of Medicine , Aalborg University , Aalborg , Denmark
| | - Toshiyuki Asaki
- SMI , Department of Health Science and Technology, Faculty of Medicine , Aalborg University , Aalborg , Denmark
| | - Thomas Graven-Nielsen
- Center for Neuroplasticity and Pain (CNAP), SMI , Department of Health Science and Technology , Aalborg University , Aalborg , Denmark
| | - Brian E. Cairns
- SMI , Department of Health Science and Technology, Faculty of Medicine , Aalborg University , Aalborg , Denmark
- Center for Neuroplasticity and Pain (CNAP), SMI , Department of Health Science and Technology , Aalborg University , Aalborg , Denmark
| | - Thomas Arendt-Nielsen
- SMI , Department of Health Science and Technology, Faculty of Medicine , Aalborg University , Aalborg , Denmark
| | - Lars Arendt-Nielsen
- SMI , Department of Health Science and Technology, Faculty of Medicine , Aalborg University , Aalborg , Denmark
- Center for Neuroplasticity and Pain (CNAP), SMI , Department of Health Science and Technology , Aalborg University , Aalborg , Denmark
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Acid-Sensing Ion Channels as Potential Therapeutic Targets in Neurodegeneration and Neuroinflammation. Mediators Inflamm 2017; 2017:3728096. [PMID: 29056828 PMCID: PMC5625748 DOI: 10.1155/2017/3728096] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Revised: 07/29/2017] [Accepted: 08/13/2017] [Indexed: 12/21/2022] Open
Abstract
Acid-sensing ion channels (ASICs) are a family of proton-sensing channels that are voltage insensitive, cation selective (mostly permeable to Na+), and nonspecifically blocked by amiloride. Derived from 5 genes (ACCN1-5), 7 subunits have been identified, 1a, 1b, 2a, 2b, 3, 4, and 5, that are widely expressed in the peripheral and central nervous system as well as other tissues. Over the years, different studies have shown that activation of these channels is linked to various physiological and pathological processes, such as memory, learning, fear, anxiety, ischemia, and multiple sclerosis to name a few, so their potential as therapeutic targets is increasing. This review focuses on recent advances that have helped us to better understand the role played by ASICs in different pathologies related to neurodegenerative diseases, inflammatory processes, and pain.
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Abstract
Fibromyalgia appears to present in subgroups with regard to biological pain induction, with primarily inflammatory, neuropathic/neurodegenerative, sympathetic, oxidative, nitrosative, or muscular factors and/or central sensitization. Recent research has also discussed glial activation or interrupted dopaminergic neurotransmission, as well as increased skin mast cells and mitochondrial dysfunction. Therapy is difficult, and the treatment options used so far mostly just have the potential to address only one of these aspects. As ambroxol addresses all of them in a single substance and furthermore also reduces visceral hypersensitivity, in fibromyalgia existing as irritable bowel syndrome or chronic bladder pain, it should be systematically investigated for this purpose. Encouraged by first clinical observations of two working groups using topical or oral ambroxol for fibromyalgia treatments, the present paper outlines the scientific argument for this approach by looking at each of the aforementioned aspects of this complex disease and summarizes putative modes of action of ambroxol. Nevertheless, at this point the evidence basis for ambroxol is not strong enough for clinical recommendation.
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Affiliation(s)
- Kai-Uwe Kern
- Institute of Pain Medicine/Pain Practice, Wiesbaden, Germany
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32
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Araújo-Filho HG, Pereira EWM, Rezende MM, Menezes PP, Araújo AAS, Barreto RSS, Martins AOBPB, Albuquerque TR, Silva BAF, Alcantara IS, Coutinho HDM, Menezes IRA, Quintans-Júnior LJ, Quintans JSS. D-limonene exhibits superior antihyperalgesic effects in a β-cyclodextrin-complexed form in chronic musculoskeletal pain reducing Fos protein expression on spinal cord in mice. Neuroscience 2017; 358:158-169. [PMID: 28673718 DOI: 10.1016/j.neuroscience.2017.06.037] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 06/12/2017] [Accepted: 06/21/2017] [Indexed: 10/19/2022]
Abstract
Chronic musculoskeletal pain is one of the main symptoms found in Fibromyalgia with unclear etiology and limited pharmacological treatment. The aim of this study was to complex LIM in β-cyclodextrin (LIM-βCD) and then evaluate its antihyperalgesic effect in an animal model of chronic musculoskeletal pain. Differential scanning calorimetry and scanning electron microscopy was used for the characterization of the inclusion complex. Male Swiss mice were used for experimental procedures where mechanical hyperalgesia, thermal hyperalgesia, muscular strength, Fos immunofluorescence was studied after induction of hyperalgesia. Mechanism of action was also investigated through tail flick test and capsaicin-induced nociception. Endothermic events and morphological changes showed that the slurry complex method was the best method for the complexation. After induction of hyperalgesia, the oral administration of LIM-βCD (50mg/kg) significantly increased the paw withdrawal threshold compared to uncomplexed limonene. Fos immunofluorescence showed that both compounds significantly decreased the number of Fos-positive cells in the dorsal horn. In nociceptive tests, FLU was able to reverse the antinociceptive effect of LIM-βCD. After intraplantar administration of capsaicin, LIM was able to significantly decrease time to lick. LIM-βCD has antihyperalgesic action superior to its uncomplexed form, with possible action in the dorsal horn of the spinal cord. These results suggest the possible applicability of LIM, uncomplexed or complexed with βCD, in conditions such as FM and neuropathic pain, for which there are currently only limited pharmacological options.
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Affiliation(s)
- Heitor G Araújo-Filho
- Laboratory of Neuroscience and Pharmacological Assays (LANEF). Department of Physiology, Federal University of Sergipe, São Cristóvão, SE, Brazil
| | - Erik W M Pereira
- Laboratory of Neuroscience and Pharmacological Assays (LANEF). Department of Physiology, Federal University of Sergipe, São Cristóvão, SE, Brazil
| | - Marília M Rezende
- Laboratory of Neuroscience and Pharmacological Assays (LANEF). Department of Physiology, Federal University of Sergipe, São Cristóvão, SE, Brazil
| | - Paula P Menezes
- Department of Pharmacy, Federal University of Sergipe, São Cristóvão, SE, Brazil
| | - Adriano A S Araújo
- Department of Pharmacy, Federal University of Sergipe, São Cristóvão, SE, Brazil
| | - Rosana S S Barreto
- Department of Health Education, Federal University of Sergipe, Largato, SE, Brazil
| | | | - Thaís R Albuquerque
- Department of Biological Chemistry, Regional University of Crato, Crato, CE, Brazil
| | - Bruno A F Silva
- Department of Biological Chemistry, Regional University of Crato, Crato, CE, Brazil
| | - Isabel S Alcantara
- Department of Biological Chemistry, Regional University of Crato, Crato, CE, Brazil
| | | | - Irwin R A Menezes
- Department of Biological Chemistry, Regional University of Crato, Crato, CE, Brazil
| | - Lucindo J Quintans-Júnior
- Laboratory of Neuroscience and Pharmacological Assays (LANEF). Department of Physiology, Federal University of Sergipe, São Cristóvão, SE, Brazil
| | - Jullyana S S Quintans
- Laboratory of Neuroscience and Pharmacological Assays (LANEF). Department of Physiology, Federal University of Sergipe, São Cristóvão, SE, Brazil.
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Abdelhamid RE, Sluka KA. ASICs Mediate Pain and Inflammation in Musculoskeletal Diseases. Physiology (Bethesda) 2016; 30:449-59. [PMID: 26525344 DOI: 10.1152/physiol.00030.2015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Chronic musculoskeletal pain is debilitating and affects ∼ 20% of adults. Tissue acidosis is present in painful musculoskeletal diseases like rheumatoid arthritis. ASICs are located on skeletal muscle and joint nociceptors as well as on nonneuronal cells in the muscles and joints, where they mediate nociception. This review discusses the properties of different types of ASICs, factors affecting their pH sensitivity, and their role in musculoskeletal hyperalgesia and inflammation.
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Affiliation(s)
- Ramy E Abdelhamid
- Department of Physical Therapy and Rehabilitation Science, Neuroscience Graduate Program, Pain Research Program, University of Iowa, Iowa City, Iowa
| | - Kathleen A Sluka
- Department of Physical Therapy and Rehabilitation Science, Neuroscience Graduate Program, Pain Research Program, University of Iowa, Iowa City, Iowa
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34
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Munkholm TK, Arendt-Nielsen L. The interaction between NGF-induced hyperalgesia and acid-provoked pain in the infrapatellar fat pad and tibialis anterior muscle of healthy volunteers. Eur J Pain 2016; 21:474-485. [PMID: 27634419 DOI: 10.1002/ejp.941] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/12/2016] [Indexed: 11/08/2022]
Abstract
BACKGROUND Tissue pH is lowered in inflamed tissues, and the increased proton concentration activates acid-sensing ion channels (ASICs), contributing to pain and hyperalgesia. ASICs can be upregulated by nerve growth factor (NGF). The aim of this study was to investigate two new human experimental pain models combining NGF- and acid-induced pain in a randomized, controlled, double-blind study. METHODS In experiment 1, volunteers (N = 16) received an injection of either NGF or isotonic saline in each infrapatellar fat pad (IFP). One day after 5 mL of phosphate-buffered acidic saline was infused into each IFP at a rate of 20 mL/h. In experiment 2, the tibialis anterior (TA) muscle of additional volunteers (N = 16) was examined, following the same procedure except that the volume and infusion rate of acid were different (10 mL, 30 mL/h). Continuous pain ratings were recorded during and after acid infusions. In addition, soreness scores on a Likert scale and pressure pain thresholds (PPTs) were assessed. RESULTS The PPT of the IFP was significantly decreased at the NGF injection site on day 1, but acid-provoked pain ratings and the change in PPT from pre- to postinfusion between the knees were similar. In the muscle pain model, local mechanical hyperalgesia developed 3 h after the NGF injection and a significant additional decrease in PPT was found after acid infusion compared to preinfusion. CONCLUSIONS NGF sensitization in the IFP was not facilitated by acid, whereas an acid-provoked enhancement of muscle hyperalgesia was found. NGF sensitization of adipose tissue responds differently to acid provocation compared to muscle tissue. SIGNIFICANCE Quantification of two novel pain models combining NGF and acid. Hyperalgesia developed after NGF injection in the infrapatellar fat pad, but it was not facilitated by acid provocation. Contrary, NGF-induced hyperalgesia in muscle tissue was enhanced by acid.
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Affiliation(s)
- T K Munkholm
- Center for Sensory-Motor Interaction (SMI), Aalborg University, Denmark
| | - L Arendt-Nielsen
- Center for Sensory-Motor Interaction (SMI), Aalborg University, Denmark
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Resident Macrophages in Muscle Contribute to Development of Hyperalgesia in a Mouse Model of Noninflammatory Muscle Pain. THE JOURNAL OF PAIN 2016; 17:1081-1094. [PMID: 27377621 DOI: 10.1016/j.jpain.2016.06.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 04/04/2016] [Accepted: 06/21/2016] [Indexed: 01/01/2023]
Abstract
UNLABELLED Macrophages play a role in innate immunity within the body, are located in muscle tissue, and can release inflammatory cytokines that sensitize local nociceptors. In this study we investigate the role of resident macrophages in the noninflammatory muscle pain model induced by 2 pH 4.0 preservative-free sterile saline (pH 4.0) injections 5 days apart in the gastrocnemius muscle. We showed that injecting 2 pH 4.0 injections into the gastrocnemius muscle increased the number of local muscle macrophages, and depleting muscle macrophages with clodronate liposomes before acid injections attenuated the hyperalgesia produced by this model. To further examine the contribution of local macrophages to this hyperalgesia, we injected mice intramuscularly with C34, a toll-like receptor 4 (TLR4) antagonist. When given before the first pH 4.0 injection, C34 attenuated the muscle and tactile hyperalgesia produced by the model. However, when given before the second injection C34 had no effect on the development of hyperalgesia. Then to test whether activation of local macrophages sensitizes nociceptors to normally non-nociceptive stimuli we replaced either the first or second acid injection with the immune cell activator lipopolysaccharide, or the inflammatory cytokine interleukin (IL)-6. Injecting LPS or IL-6 instead of the either the first or second pH 4.0 injection resulted in a dose-dependent increase in paw withdrawal responses and decrease in muscle withdrawal thresholds. The highest doses of LPS and IL-6 resulted in development of hyperalgesia bilaterally. The present study showed that resident macrophages in muscle are key to development of chronic muscle pain. PERSPECTIVE This article presents evidence for the role of macrophages in the development of chronic muscle pain using a mouse model. These data suggest that macrophages could be a potential therapeutic target to prevent transition of acute to chronic muscle pain particularly in tissue acidosis conditions.
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Neurobiology of fibromyalgia and chronic widespread pain. Neuroscience 2016; 338:114-129. [PMID: 27291641 DOI: 10.1016/j.neuroscience.2016.06.006] [Citation(s) in RCA: 396] [Impact Index Per Article: 49.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 06/02/2016] [Accepted: 06/03/2016] [Indexed: 12/13/2022]
Abstract
Fibromyalgia is the current term for chronic widespread musculoskeletal pain for which no alternative cause can be identified. The underlying mechanisms, in both human and animal studies, for the continued pain in individuals with fibromyalgia will be explored in this review. There is a substantial amount of support for alterations of central nervous system nociceptive processing in people with fibromyalgia, and that psychological factors such as stress can enhance the pain experience. Emerging evidence has begun exploring other potential mechanisms including a peripheral nervous system component to the generation of pain and the role of systemic inflammation. We will explore the data and neurobiology related to the role of the CNS in nociceptive processing, followed by a short review of studies examining potential peripheral nervous system changes and cytokine involvement. We will not only explore the data from human subjects with fibromyalgia but will relate this to findings from animal models of fibromyalgia. We conclude that fibromyalgia and related disorders are heterogenous conditions with a complicated pathobiology with patients falling along a continuum with one end a purely peripherally driven painful condition and the other end of the continuum is when pain is purely centrally driven.
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Is rotating between static and dynamic work beneficial for our fatigue state? J Electromyogr Kinesiol 2016; 28:104-13. [DOI: 10.1016/j.jelekin.2016.04.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 03/29/2016] [Accepted: 04/05/2016] [Indexed: 11/17/2022] Open
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Quantitative and Qualitative Responses to Topical Cold in Healthy Caucasians Show Variance between Individuals but High Test-Retest Reliability. PLoS One 2016; 11:e0151972. [PMID: 27007696 PMCID: PMC4805254 DOI: 10.1371/journal.pone.0151972] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 03/07/2016] [Indexed: 01/21/2023] Open
Abstract
Increased sensitivity to cold may be a predictor of persistent pain, but cold pain threshold is often viewed as unreliable. This study aimed to determine the within-subject reliability and between-subject variance of cold response, measured comprehensively as cold pain threshold plus pain intensity and sensation quality at threshold. A test-retest design was used over three sessions, one day apart. Response to cold was assessed at four sites (thenar eminence, volar forearm, tibialis anterior, plantar foot). Cold pain threshold was measured using a Medoc thermode and standard method of limits. Intensity of pain at threshold was rated using a 10cm visual analogue scale. Quality of sensation at threshold was quantified with indices calculated from subjects' selection of descriptors from a standard McGill Pain Questionnaire. Within-subject reliability for each measure was calculated with intra-class correlation coefficients and between-subject variance was evaluated as group coefficient of variation percentage (CV%). Gender and site comparisons were also made. Forty-five healthy adults participated: 20 male, 25 female; mean age 29 (range 18–56) years. All measures at all four test sites showed high within-subject reliability: cold pain thresholds r = 0.92–0.95; pain rating r = 0.93–0.97; McGill pain quality indices r = 0.87–0.85. In contrast, all measures showed wide between-subject variance (CV% between 51.4% and 92.5%). Upper limb sites were consistently more sensitive than lower limb sites, but equally reliable. Females showed elevated cold pain thresholds, although similar pain intensity and quality to males. Females were also more reliable and showed lower variance for all measures. Thus, although there was clear population variation, response to cold for healthy individuals was found to be highly reliable, whether measured as pain threshold, pain intensity or sensation quality. A comprehensive approach to cold response testing therefore may add validity and improve acceptance of this potentially important pain measure.
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Peng Z, Li WG, Huang C, Jiang YM, Wang X, Zhu MX, Cheng X, Xu TL. ASIC3 Mediates Itch Sensation in Response to Coincident Stimulation by Acid and Nonproton Ligand. Cell Rep 2015; 13:387-98. [PMID: 26440887 DOI: 10.1016/j.celrep.2015.09.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Revised: 07/20/2015] [Accepted: 08/31/2015] [Indexed: 11/25/2022] Open
Abstract
The regulation and mechanisms underlying itch sensation are complex. Here, we report a role for acid-sensing ion channel 3 (ASIC3) in mediating itch evoked by certain pruritogens during tissue acidosis. Co-administration of acid with Ser-Leu-Ile-Gly-Arg-Leu-NH2 (SL-NH2) increased scratching behavior in wild-type, but not ASIC3-null, mice, implicating the channel in coincident detection of acidosis and pruritogens. Mechanistically, SL-NH2 slowed desensitization of proton-evoked currents by targeting the previously identified nonproton ligand-sensing domain located in the extracellular region of ASIC3 channels in primary sensory neurons. Ablation of the ASIC3 gene reduced dry-skin-induced scratching behavior and pathological changes under conditions with concomitant inflammation. Taken together, our data suggest that ASIC3 mediates itch sensation via coincident detection of acidosis and nonproton ligands that act at the nonproton ligand-sensing domain of the channel.
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Affiliation(s)
- Zhong Peng
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Wei-Guang Li
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Chen Huang
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Yi-Ming Jiang
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Xiang Wang
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Michael Xi Zhu
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Xiaoyang Cheng
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.
| | - Tian-Le Xu
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.
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Gregory NS, Whitley PE, Sluka KA. Effect of Intramuscular Protons, Lactate, and ATP on Muscle Hyperalgesia in Rats. PLoS One 2015; 10:e0138576. [PMID: 26378796 PMCID: PMC4574767 DOI: 10.1371/journal.pone.0138576] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 09/01/2015] [Indexed: 11/27/2022] Open
Abstract
Chronic muscle pain is a significant health problem leading to disability[1]. Muscle fatigue can exacerbate muscle pain. Metabolites, including ATP, lactate, and protons, are released during fatiguing exercise and produce pain in humans. These substances directly activate purinergic (P2X) and acid sensing ion channels (ASICs) on muscle nociceptors, and when combined, produce a greater increase in neuron firing than when given alone. Whether the enhanced effect of combining protons, lactate, and ATP is the sum of individual effects (additive) or more than the sum of individual effects (synergistic) is unknown. Using a rat model of muscle nociceptive behavior, we tested each of these compounds individually over a range of physiologic and supra-physiologic concentrations. Further, we combined all three compounds in a series of dilutions and tested their effect on muscle nociceptive behavior. We also tested a non-hydrolyzable form of ATP (α,β-meATP) alone and in combination with lactate and acidic pH. Surprisingly, we found no dose-dependent effect on muscle nociceptive behavior for protons, lactate, or ATP when given alone. We similarly found no effect after application of each two-metabolite combination. Only pH 4 saline and α,β-meATP produced hyperalgesia when given alone. When all 3 substances were combined, however, ATP (2.4μm), lactate (10mM), and acidic pH (pH 6.0) produced an enhanced effect greater than the sum of the effects of the individual components, i.e. synergism. α,β me ATP (3nmol), on the other hand, showed no enhanced effects when combined with lactate (10mM) or acidic pH (pH 6.0), i.e. additive. These data suggest that combining fatigue metabolites in muscle produces a synergistic effect on muscle nociception.
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Affiliation(s)
- Nicholas S. Gregory
- Neuroscience Graduate Program, University of Iowa, Iowa City, Iowa, United States of America
| | | | - Kathleen A. Sluka
- Neuroscience Graduate Program, University of Iowa, Iowa City, Iowa, United States of America
- Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, Iowa, United States of America
- * E-mail:
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Sato H, Castrillon E, Cairns B, Bendixen K, Wang K, Nakagawa T, Wajima K, Svensson P. Intramuscular pH modulates glutamate-evoked masseter muscle pain magnitude in humans. Eur J Pain 2015; 20:106-15. [DOI: 10.1002/ejp.697] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2015] [Indexed: 11/10/2022]
Affiliation(s)
- H. Sato
- Department of Dentistry & Oral Surgery; School of Medicine; Keio University; Tokyo Japan
- Department of Dentistry & Oral Surgery; Kawasaki Municipal Kawasaki Hospital; Japan
| | - E.E. Castrillon
- Department of Clinical Oral Physiology; School of Dentistry; Aarhus University; Denmark
- Scandinavian Center for Orofacial Neuroscience (SCON); Huddinge Sweden
| | - B.E. Cairns
- Faculty of Pharmaceutical Sciences; The University of British Columbia; Vancouver Canada
- Center for Sensory-Motor Interaction; The Faculty of Medicine; Department of Health Science and Technology; Aalborg University; Denmark
| | - K.H. Bendixen
- Department of Clinical Oral Physiology; School of Dentistry; Aarhus University; Denmark
- Scandinavian Center for Orofacial Neuroscience (SCON); Huddinge Sweden
| | - K. Wang
- Center for Sensory-Motor Interaction; The Faculty of Medicine; Department of Health Science and Technology; Aalborg University; Denmark
| | - T. Nakagawa
- Department of Dentistry & Oral Surgery; School of Medicine; Keio University; Tokyo Japan
| | - K. Wajima
- Department of Dentistry & Oral Surgery; School of Medicine; Keio University; Tokyo Japan
| | - P. Svensson
- Department of Clinical Oral Physiology; School of Dentistry; Aarhus University; Denmark
- Scandinavian Center for Orofacial Neuroscience (SCON); Huddinge Sweden
- Department of Dental Medicine; Karolinska Institute; Huddinge Sweden
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42
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Effect of protons on the mechanical response of rat muscle nociceptive fibers and neurons in vitro. Neurosci Res 2015; 92:46-52. [DOI: 10.1016/j.neures.2014.11.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Revised: 11/02/2014] [Accepted: 11/05/2014] [Indexed: 01/16/2023]
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Sutton BC, Opp MR. Acute increases in intramuscular inflammatory cytokines are necessary for the development of mechanical hypersensitivity in a mouse model of musculoskeletal sensitization. Brain Behav Immun 2015; 44:213-20. [PMID: 25449670 DOI: 10.1016/j.bbi.2014.10.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 10/16/2014] [Accepted: 10/16/2014] [Indexed: 12/25/2022] Open
Abstract
Musculoskeletal pain is a widespread health problem in the United States. Back pain, neck pain, and facial pain are three of the most prevalent types of chronic pain, and each is characterized as musculoskeletal in origin. Despite its prevalence, preclinical research investigating musculoskeletal pain is limited. Musculoskeletal sensitization is a preclinical model of muscle pain that produces mechanical hypersensitivity. In a rodent model of musculoskeletal sensitization, mechanical hypersensitivity develops at the hind paws after injection of acidified saline (pH 4.0) into the gastrocnemius muscle. Inflammatory cytokines contribute to pain during a variety of pathologies, and in this study we investigate the role of local, intramuscular cytokines in the development of mechanical hypersensitivity after musculoskeletal sensitization in mice. Local intramuscular concentrations of interleukin-1β (IL-1), IL-6 and tumor necrosis factor-α (TNF) were quantified following injection of normal (pH 7.2) or acidified saline into the gastrocnemius muscle. A cell-permeable inhibitor was used to determine the impact on mechanical hypersensitivity of inhibiting nuclear translocation of the transcription factor nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) prior to musculoskeletal sensitization. The role of individual cytokines in mechanical hypersensitivity following musculoskeletal sensitization was assessed using knockout mice lacking components of the IL-1, IL-6 or TNF systems. Collectively, our data demonstrate that acidified saline injection increases intramuscular IL-1 and IL-6, but not TNF; that intramuscular pre-treatment with an NF-κB inhibitor blocks mechanical hypersensitivity; and that genetic manipulation of the IL-1 and IL-6, but not TNF systems, prevents mechanical hypersensitivity following musculoskeletal sensitization. These data establish that actions of IL-1 and IL-6 in local muscle tissue play an acute regulatory role in the development of mechanical hypersensitivity following musculoskeletal sensitization.
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Affiliation(s)
- Blair C Sutton
- Anesthesiology & Pain Medicine University of Washington, Seattle, WA, United States; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, United States
| | - Mark R Opp
- Anesthesiology & Pain Medicine University of Washington, Seattle, WA, United States; Program in Neurobiology and Behavior University of Washington, Seattle, WA, United States.
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Qiu F, Qiu CY, Cai H, Liu TT, Qu ZW, Yang Z, Li JD, Zhou QY, Hu WP. Oxytocin inhibits the activity of acid-sensing ion channels through the vasopressin, V1A receptor in primary sensory neurons. Br J Pharmacol 2015; 171:3065-76. [PMID: 24641084 DOI: 10.1111/bph.12635] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 01/01/2014] [Accepted: 02/04/2014] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND AND PURPOSE A growing number of studies have demonstrated that oxytocin (OT) plays an analgesic role in modulation of nociception and pain. Most work to date has focused on the central mechanisms of OT analgesia, but little is known about whether peripheral mechanisms are also involved. Acid-sensing ion channels (ASICs) are distributed in peripheral sensory neurons and participate in nociception. Here, we investigated the effects of OT on the activity of ASICs in dorsal root ganglion (DRG) neurons. EXPERIMENTAL APPROACH Electrophysiological experiments were performed on neurons from rat DRG. Nociceptive behaviour was induced by acetic acid in rats and mice lacking vasopressin, V1A receptors. KEY RESULTS OT inhibited the functional activity of native ASICs. Firstly, OT dose-dependently decreased the amplitude of ASIC currents in DRG neurons. Secondly, OT inhibition of ASIC currents was mimicked by arginine vasopressin (AVP) and completely blocked by the V1A receptor antagonist SR49059, but not by the OT receptor antagonist L-368899. Thirdly, OT altered acidosis-evoked membrane excitability of DRG neurons and significantly decreased the amplitude of the depolarization and number of action potentials induced by acid stimuli. Finally, peripherally administered OT or AVP inhibited nociceptive responses to intraplantar injection of acetic acid in rats. Both OT and AVP also induced an analgesic effect on acidosis-evoked pain in wild-type mice, but not in V1A receptor knockout mice. CONCLUSIONS AND IMPLICATIONS These results reveal a novel peripheral mechanism for the analgesic effect of OT involving the modulation of native ASICs in primary sensory neurons mediated by V1A receptors.
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Affiliation(s)
- Fang Qiu
- Department of Pharmacology, Hubei University of Science and Technology, Xianning, China; College of Life Sciences, Hubei University, Wuhan, China
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Gregory NS, Brito RG, Fusaro MCGO, Sluka KA. ASIC3 Is Required for Development of Fatigue-Induced Hyperalgesia. Mol Neurobiol 2015; 53:1020-1030. [PMID: 25577172 DOI: 10.1007/s12035-014-9055-4] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 12/08/2014] [Indexed: 12/23/2022]
Abstract
An acute bout of exercise can exacerbate pain, hindering participation in regular exercise and daily activities. The mechanisms underlying pain in response to acute exercise are poorly understood. We hypothesized that proton accumulation during muscle fatigue activates acid-sensing ion channel 3 (ASIC3) on muscle nociceptors to produce hyperalgesia. We investigated the role of ASIC3 using genetic and pharmacological approaches in a model of fatigue-enhanced hyperalgesia. This model uses two injections of pH 5.0 saline into muscle in combination with an electrically induced fatigue of the same muscle just prior to the second injection of acid to induce mechanical hyperalgesia. We show a significant decrease in muscle force and decrease in muscle pH after 6 min of electrical stimulation. Genetic deletion of ASIC3 using knockout mice and pharmacological blockade of ASIC3 with APETx2 in muscle prevents the fatigue-enhanced hyperalgesia. However, ASIC3(-/-) mice and APETx2 have no effect on the fatigue response. Genetic deletion of ASIC3 in primary afferents innervating muscle using an HSV-1 expressing microRNA (miRNA) to ASIC3 surprisingly had no effect on the development of the hyperalgesia. Muscle fatigue increased the number of macrophages in muscle, and removal of macrophages from muscle with clodronate liposomes prevented the development of fatigue-enhanced hyperalgesia. Thus, these data suggest that fatigue reduces pH in muscle that subsequently activates ASIC3 on macrophages to enhance hyperalgesia to muscle insult.
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Affiliation(s)
- Nicholas S Gregory
- Neuroscience Graduate Program, Pain Research Program, Department of Physical Therapy and Rehabilitation Science, University of Iowa, 1-248 MEB, Iowa City, IA, 52242, USA
| | - Renan G Brito
- Department of Physiology, Federal University of Sergipe, Aracaju, Brazil
| | | | - Kathleen A Sluka
- Neuroscience Graduate Program, Pain Research Program, Department of Physical Therapy and Rehabilitation Science, University of Iowa, 1-248 MEB, Iowa City, IA, 52242, USA.
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Sluka KA, Gregory NS. The dichotomized role for acid sensing ion channels in musculoskeletal pain and inflammation. Neuropharmacology 2015; 94:58-63. [PMID: 25582293 DOI: 10.1016/j.neuropharm.2014.12.013] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 11/26/2014] [Accepted: 12/04/2014] [Indexed: 01/24/2023]
Abstract
Chronic muscle pain affects between 11 and 24% of the world's population with the majority of people experiencing musculoskeletal pain at some time in their life. Acid sensing ion channels (ASICs) are important sensors of modest decreases in extracellular pH that occur within the physiological range. These decreases in extracellular pH occur in response to inflammation, fatiguing exercise, and ischemia. Further, injection of acidic saline into muscle produces enhanced nociceptive behaviors in animals and pain in human subjects. Of the different types of ASICs, ASIC3 and ASIC1 have been implicated in transmission of nociceptive information from the musculoskeletal system. The current review will provide an overview of the evidence for ASIC3 and ASIC1 in musculoskeletal pain in both inflammatory and non-inflammatory models. This article is part of the Special Issue entitled 'Acid-Sensing Ion Channels in the Nervous System'.
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Affiliation(s)
- Kathleen A Sluka
- Department of Physical Therapy and Rehabilitation Science, Neuroscience Graduate Program, Pain Research Program, University of Iowa, Iowa City, IA 52242, USA.
| | - Nicholas S Gregory
- Department of Physical Therapy and Rehabilitation Science, Neuroscience Graduate Program, Pain Research Program, University of Iowa, Iowa City, IA 52242, USA
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Abstract
Animal models of disease states are valuable tools for developing new treatments and investigating underlying mechanisms. They should mimic the symptoms and pathology of the disease and importantly be predictive of effective treatments. Fibromyalgia is characterized by chronic widespread pain with associated co-morbid symptoms that include fatigue, depression, anxiety and sleep dysfunction. In this review, we present different animal models that mimic the signs and symptoms of fibromyalgia. These models are induced by a wide variety of methods that include repeated muscle insults, depletion of biogenic amines, and stress. All potential models produce widespread and long-lasting hyperalgesia without overt peripheral tissue damage and thus mimic the clinical presentation of fibromyalgia. We describe the methods for induction of the model, pathophysiological mechanisms for each model, and treatment profiles.
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48
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Glass N, Segal NA, Sluka KA, Torner JC, Nevitt MC, Felson DT, Bradley LA, Neogi T, Lewis CE, Frey-Law LA. Examining sex differences in knee pain: the multicenter osteoarthritis study. Osteoarthritis Cartilage 2014; 22:1100-6. [PMID: 24999111 PMCID: PMC4180745 DOI: 10.1016/j.joca.2014.06.030] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 06/07/2014] [Accepted: 06/28/2014] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To determine whether women experience greater knee pain severity than men at equivalent levels of radiographic knee osteoarthritis (OA). DESIGN AND METHODS A cross-sectional analysis of 2712 individuals (60% women) without knee replacement or a recent steroid injection. Sex differences in pain severity at each Kellgren-Lawrence (KL) grade were assessed by knee using visual analog scale (VAS) scale and Western Ontario and McMaster Universities Arthritis Index (WOMAC) with and without adjustment for age, analgesic use, Body mass index (BMI), clinic site, comorbid conditions, depression score, education, race, and widespread pain (WSP) using generalized estimating equations. Effect sizes (Cohen's d) were also calculated. Analyses were repeated in those with and without patellofemoral OA (PFOA). RESULTS Women reported higher VAS pain at all KL grades in unadjusted analyses (d = 0.21-0.31, P < 0.0001-0.0038) and in analyses adjusted for all covariates except WSP (d = 0.16-0.22, P < 0.0001-0.0472). Pain severity differences further decreased with adjustment for WSP (d = 0.10-0.18) and were significant for KL grade ≤2 (P = 0.0015) and 2 (P = 0.0200). Presence compared with absence of WSP was associated with significantly greater knee pain at all KL grades (d = 0.32-0.52, P < 0.0001-0.0008). In knees with PFOA, VAS pain severity sex differences were greater at each KL grade (d = 0.45-0.62, P = 0.0006-0.0030) and remained significant for all KL grades in adjusted analyses (d = 0.31-0.57, P = 0.0013-0.0361). Results using WOMAC were similar. CONCLUSIONS Women reported greater knee pain than men regardless of KL grade, though effect sizes were generally small. These differences increased in the presence of PFOA. The strong contribution of WSP to sex differences in knee pain suggests that central sensitivity plays a role in these differences.
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Affiliation(s)
- N. Glass
- University of Iowa, Iowa City, IA
| | | | | | | | - M. C. Nevitt
- University of California at San Francisco, San Francisco, CA
| | | | | | | | - C. E. Lewis
- Univ. of Alabama at Birmingham, Birmingham, AL
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Chen WN, Lee CH, Lin SH, Wong CW, Sun WH, Wood JN, Chen CC. Roles of ASIC3, TRPV1, and NaV1.8 in the transition from acute to chronic pain in a mouse model of fibromyalgia. Mol Pain 2014; 10:40. [PMID: 24957987 PMCID: PMC4083869 DOI: 10.1186/1744-8069-10-40] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 06/18/2014] [Indexed: 01/23/2023] Open
Abstract
Background Tissue acidosis is effective in causing chronic muscle pain. However, how muscle nociceptors contribute to the transition from acute to chronic pain is largely unknown. Results Here we showed that a single intramuscular acid injection induced a priming effect on muscle nociceptors of mice. The primed muscle nociceptors were plastic and permitted the development of long-lasting chronic hyperalgesia induced by a second acid insult. The plastic changes of muscle nociceptors were modality-specific and required the activation of acid-sensing ion channel 3 (ASIC3) or transient receptor potential cation channel V1 (TRPV1). Activation of ASIC3 was associated with increased activity of tetrodotoxin (TTX)-sensitive voltage-gated sodium channels but not protein kinase Cϵ (PKCϵ) in isolectin B4 (IB4)-negative muscle nociceptors. In contrast, increased activity of TTX-resistant voltage-gated sodium channels with ASIC3 or TRPV1 activation in NaV1.8-positive muscle nociceptors was required for the development of chronic hyperalgesia. Accordingly, compared to wild type mice, NaV1.8-null mice showed briefer acid-induced hyperalgesia (5 days vs. >27 days). Conclusion ASIC3 activation may manifest a new type of nociceptor priming in IB4-negative muscle nociceptors. The activation of ASIC3 and TRPV1 as well as enhanced NaV1.8 activity are essential for the development of long-lasting hyperalgesia in acid-induced, chronic, widespread muscle pain.
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Affiliation(s)
| | | | | | | | | | | | - Chih-Cheng Chen
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei 114, Taiwan.
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Chen WN, Chen CC. Acid mediates a prolonged antinociception via substance P signaling in acid-induced chronic widespread pain. Mol Pain 2014; 10:30. [PMID: 24886508 PMCID: PMC4039541 DOI: 10.1186/1744-8069-10-30] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 04/10/2014] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Substance P is an important neuropeptide released from nociceptors to mediate pain signals. We recently revealed antinociceptive signaling by substance P in acid-sensing ion channel 3 (ASIC3)-expressing muscle nociceptors in a mouse model of acid-induced chronic widespread pain. However, methods to specifically trigger the substance P antinociception were still lacking. RESULTS Here we show that acid could induce antinociceptive signaling via substance P release in muscle. We prevented the intramuscular acid-induced hyperalgesia by pharmacological inhibition of ASIC3 and transient receptor potential V1 (TRPV1). The antinociceptive effect of non-ASIC3, non-TRPV1 acid signaling lasted for 2 days. The non-ASIC3, non-TRPV1 acid antinociception was largely abolished in mice lacking substance P. Moreover, pretreatment with substance P in muscle mimicked the acid antinociceptive effect and prevented the hyperalgesia induced by next-day acid injection. CONCLUSIONS Acid could mediate a prolonged antinociceptive signaling via the release of substance P from muscle afferent neurons in a non-ASIC3, non-TRPV1 manner.
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Affiliation(s)
| | - Chih-Cheng Chen
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei 114, Taiwan.
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