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Quesada C, Kostenko A, Ho I, Leone C, Nochi Z, Stouffs A, Wittayer M, Caspani O, Brix Finnerup N, Mouraux A, Pickering G, Tracey I, Truini A, Treede RD, Garcia-Larrea L. Human surrogate models of central sensitization: A critical review and practical guide. Eur J Pain 2021; 25:1389-1428. [PMID: 33759294 PMCID: PMC8360051 DOI: 10.1002/ejp.1768] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 03/17/2021] [Accepted: 03/21/2021] [Indexed: 12/11/2022]
Abstract
Background As in other fields of medicine, development of new medications for management of neuropathic pain has been difficult since preclinical rodent models do not necessarily translate to the clinics. Aside from ongoing pain with burning or shock‐like qualities, neuropathic pain is often characterized by pain hypersensitivity (hyperalgesia and allodynia), most often towards mechanical stimuli, reflecting sensitization of neural transmission. Data treatment We therefore performed a systematic literature review (PubMed‐Medline, Cochrane, WoS, ClinicalTrials) and semi‐quantitative meta‐analysis of human pain models that aim to induce central sensitization, and generate hyperalgesia surrounding a real or simulated injury. Results From an initial set of 1569 reports, we identified and analysed 269 studies using more than a dozen human models of sensitization. Five of these models (intradermal or topical capsaicin, low‐ or high‐frequency electrical stimulation, thermode‐induced heat‐injury) were found to reliably induce secondary hyperalgesia to pinprick and have been implemented in multiple laboratories. The ability of these models to induce dynamic mechanical allodynia was however substantially lower. The proportion of subjects who developed hypersensitivity was rarely provided, giving rise to significant reporting bias. In four of these models pharmacological profiles allowed to verify similarity to some clinical conditions, and therefore may inform basic research for new drug development. Conclusions While there is no single “optimal” model of central sensitization, the range of validated and easy‐to‐use procedures in humans should be able to inform preclinical researchers on helpful potential biomarkers, thereby narrowing the translation gap between basic and clinical data. Significance Being able to mimic aspects of pathological pain directly in humans has a huge potential to understand pathophysiology and provide animal research with translatable biomarkers for drug development. One group of human surrogate models has proven to have excellent predictive validity: they respond to clinically active medications and do not respond to clinically inactive medications, including some that worked in animals but failed in the clinics. They should therefore inform basic research for new drug development.
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Affiliation(s)
- Charles Quesada
- NeuroPain lab, Lyon Centre for Neuroscience Inserm U1028, Lyon, France.,Pain Center Neurological Hospital (CETD), Hospices Civils de Lyon, Lyon, France
| | - Anna Kostenko
- Department of Neurophysiology, Mannheim center for Translational Neurosciences, Heidelberg University, Heidelberg, Germany
| | - Idy Ho
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Caterina Leone
- Department of Human Neuroscience, Sapienza University, Rome, Italy
| | - Zahra Nochi
- Danish Pain Research Center, Dept of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Alexandre Stouffs
- Institute of Neuroscience (IoNS), Université Catholique de Louvain (UCLouvain), Ottignies-Louvain-la-Neuve, Belgium
| | - Matthias Wittayer
- Department of Neurophysiology, Mannheim center for Translational Neurosciences, Heidelberg University, Heidelberg, Germany
| | - Ombretta Caspani
- Department of Neurophysiology, Mannheim center for Translational Neurosciences, Heidelberg University, Heidelberg, Germany
| | - Nanna Brix Finnerup
- Danish Pain Research Center, Dept of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - André Mouraux
- Institute of Neuroscience (IoNS), Université Catholique de Louvain (UCLouvain), Ottignies-Louvain-la-Neuve, Belgium
| | | | - Irene Tracey
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Andrea Truini
- Department of Human Neuroscience, Sapienza University, Rome, Italy
| | - Rolf-Detlef Treede
- Department of Neurophysiology, Mannheim center for Translational Neurosciences, Heidelberg University, Heidelberg, Germany
| | - Luis Garcia-Larrea
- NeuroPain lab, Lyon Centre for Neuroscience Inserm U1028, Lyon, France.,Pain Center Neurological Hospital (CETD), Hospices Civils de Lyon, Lyon, France
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Hansen MS, Becerra L, Dahl JB, Borsook D, Mårtensson J, Christensen A, Nybing JD, Havsteen I, Boesen M, Asghar MS. Brain resting-state connectivity in the development of secondary hyperalgesia in healthy men. Brain Struct Funct 2019; 224:1119-1139. [PMID: 30631932 DOI: 10.1007/s00429-018-01819-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 12/16/2018] [Indexed: 01/25/2023]
Abstract
Central sensitization is a condition in which there is an abnormal responsiveness to nociceptive stimuli. As such, the process may contribute to the development and maintenance of pain. Factors influencing the propensity for development of central sensitization have been a subject of intense debate and remain elusive. Injury-induced secondary hyperalgesia can be elicited by experimental pain models in humans, and is believed to be a result of central sensitization. Secondary hyperalgesia may thus reflect the individual level of central sensitization. The objective of this study was to investigate possible associations between increasing size of secondary hyperalgesia area and brain connectivity in known resting-state networks. We recruited 121 healthy participants (male, age 22, SD 3.35) who underwent resting-state functional magnetic resonance imaging. Prior to the scan session, areas of secondary hyperalgesia following brief thermal sensitization (3 min. 45 °C heat stimulation) were evaluated in all participants. 115 participants were included in the final analysis. We found a positive correlation (increasing connectivity) with increasing area of secondary hyperalgesia in the sensorimotor- and default mode networks. We also observed a negative correlation (decreasing connectivity) with increasing secondary hyperalgesia area in the sensorimotor-, fronto-parietal-, and default mode networks. Our findings indicate that increasing area of secondary hyperalgesia is associated with increasing and decreasing connectivity in multiple networks, suggesting that differences in the propensity for central sensitization, assessed as secondary hyperalgesia areas, may be expressed as differences in the resting-state central neuronal activity.
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Affiliation(s)
- Morten Sejer Hansen
- Department of Anaesthesiology, 4231, Centre of Head and Orthopaedics, Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark.
- Department of Radiology, Copenhagen University Hospital Bispebjerg and Frederiksberg, Bispebjerg Bakke 23, 2400, Copenhagen, NV, Denmark.
| | - Lino Becerra
- Invicro, A Konica Minolta Company, 27 Drydock Avenue, 7th Floor West, Boston, MA, 02210, USA
| | - Jørgen Berg Dahl
- Department of Anaesthesiology, Copenhagen University Hospital Bispebjerg and Frederiksberg, Bispebjerg Bakke 23, 2400, Copenhagen, NV, Denmark
| | - David Borsook
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
- Department of Psychiatry, McLean Hospital, Harvard Medical School, Boston, MA, USA
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Johan Mårtensson
- Department of Clinical Sciences, Faculty of Medicine, Lund University, Box 213, 221 00, Lund, Sweden
| | - Anders Christensen
- Department of Radiology, Copenhagen University Hospital Bispebjerg and Frederiksberg, Bispebjerg Bakke 23, 2400, Copenhagen, NV, Denmark
| | - Janus Damm Nybing
- Department of Radiology, Copenhagen University Hospital Bispebjerg and Frederiksberg, Bispebjerg Bakke 23, 2400, Copenhagen, NV, Denmark
| | - Inger Havsteen
- Department of Radiology, Copenhagen University Hospital Bispebjerg and Frederiksberg, Bispebjerg Bakke 23, 2400, Copenhagen, NV, Denmark
| | - Mikael Boesen
- Department of Radiology and the Parker Institute, Copenhagen University Hospital Bispebjerg and Frederiksberg, Bispebjerg Hospital, Bispebjerg Bakke 23, 2400, Copenhagen, NV, Denmark
| | - Mohammad Sohail Asghar
- Department of Neuroanaesthesiology, Neurocentre, Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark
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Fabritius ML, Wetterslev J, Mathiesen O, Dahl JB. Dose-related beneficial and harmful effects of gabapentin in postoperative pain management - post hoc analyses from a systematic review with meta-analyses and trial sequential analyses. J Pain Res 2017; 10:2547-2563. [PMID: 29138592 PMCID: PMC5677383 DOI: 10.2147/jpr.s138519] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Background During the last 15 years, gabapentin has become an established component of postoperative pain treatment. Gabapentin has been employed in a wide range of doses, but little is known about the optimal dose, providing the best balance between benefit and harm. This systematic review with meta-analyses aimed to explore the beneficial and harmful effects of various doses of gabapentin administered to surgical patients. Materials and methods Data in this paper were derived from an original review, and the subgroup analyses were predefined in an International Prospective Register of Systematic Reviews published protocol: PROSPERO (ID: CRD42013006538). The methods followed Cochrane guidelines. The Cochrane Library’s CENTRAL, PubMed, EMBASE, Science Citation Index Expanded, Google Scholar, and FDA database were searched for relevant trials. Randomized clinical trials comparing gabapentin versus placebo were included. Four different dose intervals were investigated: 0–350, 351–700, 701–1050, and >1050 mg. Primary co-outcomes were 24-hour morphine consumption and serious adverse events (SAEs), with emphasis put on trials with low risk of bias. Results One hundred and twenty-two randomized clinical trials, with 8466 patients, were included. Sixteen were overall low risk of bias. No consistent increase in morphine-sparing effect was observed with increasing doses of gabapentin from the trials with low risk of bias. Analyzing all trials, the smallest and the highest dose subgroups demonstrated numerically the most prominent reduction in morphine consumption. Twenty-seven trials reported 72 SAEs, of which 83% were reported in the >1050 mg subgroup. No systematic increase in SAEs was observed with increasing doses of gabapentin. Conclusion Data were sparse, and the small number of trials with low risk of bias is a major limitation for firm conclusions. Taking these limitations into account, we were not able to demonstrate a clear relationship between the dosage of gabapentin and opioid-sparing or harmful effects. These subgroup analyses are exploratory and hypothesis-generating for future trialists.
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Affiliation(s)
- Maria Louise Fabritius
- Department of Anaesthesiology and Intensive Care, Bispebjerg and Frederiksberg Hospitals, Copenhagen, Denmark
| | - Jørn Wetterslev
- Copenhagen Trial Unit, Centre for Clinical Intervention Research, Copenhagen University Hospital, Copenhagen, Denmark
| | - Ole Mathiesen
- Department of Anaesthesiology, Zealand University Hospital, Køge, Denmark
| | - Jørgen B Dahl
- Department of Anaesthesiology and Intensive Care, Bispebjerg and Frederiksberg Hospitals, Copenhagen, Denmark
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Hansen MS, Wetterslev J, Pipper CB, Asghar MS, Dahl JB. Heat pain detection threshold is associated with the area of secondary hyperalgesia following brief thermal sensitization: a study of healthy male volunteers. J Pain Res 2017; 10:265-274. [PMID: 28184167 PMCID: PMC5291329 DOI: 10.2147/jpr.s121189] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Introduction The area of secondary hyperalgesia following brief thermal sensitization (BTS) of the skin and heat pain detection thresholds (HPDT) may both have predictive abilities in regards to pain sensitivity and clinical pain states. The association between HPDT and secondary hyperalgesia, however, remains unsettled, and the dissimilarities in physiologic properties suggest that they may represent 2 distinctively different pain entities. The aim of this study was to investigate the association between HPDT and BTS-induced secondary hyperalgesia. Methods A sample of 121 healthy male participants was included and tested on 2 separate study days with BTS (45°C, 3 minutes), HPDT, and pain during thermal stimulation (45°C, 1 minute). Areas of secondary hyperalgesia were quantified after monofilament pinprick stimulation. The pain catastrophizing scale (PCS) and hospital anxiety and depression scale (HADS) were also applied. Results A significant association between HPDT and the size of the area of secondary hyperalgesia (p<0.0001) was found. The expected change in area of secondary hyperalgesia due to a 1-degree increase in HPDT was estimated to be −27.38 cm2, 95% confidence interval (CI) of −37.77 to −16.98 cm2, with an R2 of 0.19. Likewise, a significant association between HADS-depression subscore and area of secondary hyperalgesia (p=0.046) was found, with an estimated expected change in secondary hyperalgesia to a 1-point increase in HADS-depression subscore of 11 cm2, 95% CI (0.19–21.82), and with R2 of 0.03. We found no significant associations between secondary hyperalgesia area and PCS score or pain during thermal stimulation. Conclusion HPDT and the area of secondary hyperalgesia after BTS are significantly associated; however, with an R2 of only 19%, HPDT only offers a modest explanation of the inter-participant variation in the size of the secondary hyperalgesia area elicited by BTS.
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Affiliation(s)
- Morten Sejer Hansen
- Department of Anesthesiology, 4231, Centre of Head and Orthopedics, Rigshospitalet
| | - Jørn Wetterslev
- Copenhagen Trial Unit, Centre for Clinical Intervention Research, Department 7812
| | | | | | - Jørgen Berg Dahl
- Department of Anesthesiology, Department Z, Bispebjerg Hospital, Copenhagen, Denmark
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5
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van Amerongen G, de Boer MW, Groeneveld GJ, Hay JL. A literature review on the pharmacological sensitivity of human evoked hyperalgesia pain models. Br J Clin Pharmacol 2016; 82:903-22. [PMID: 27203797 DOI: 10.1111/bcp.13018] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 05/13/2016] [Accepted: 05/18/2016] [Indexed: 02/06/2023] Open
Abstract
AIMS Human evoked pain models can be used to determine the efficacy of new and existing analgesics and to aid in the identification of new targets. Aspects of neuropathic pain can be simulated by inducing hyperalgesia resulting from provoked sensitization. The present literature review aimed to provide insight into the sensitivity of different hyperalgesia and allodynia models of pharmacological treatment. METHODS A literature search was performed to identify randomized, double-blind, placebo-controlled studies that included human hyperalgesia pain models and investigated the pharmacodynamic effects of different classes of drugs. RESULTS Three hyperalgesia models [ultraviolet B (UVB) irradiation, capsaicin and thermode burn] have been used extensively. Assessment of hyperalgesia/allodynia and pharmacological effect are measured using challenge tests, which generally comprise thermal (heat/cold) or mechanical stimulation (pin-prick, stroking or impact). The UVB model was sensitive to the antihyperalgesic effects of nonsteroidal anti-inflammatory drugs (NSAIDs) and opioids. The capsaicin model was partially sensitive to opioids. The burn model did not detect any antihyperalgesic effects when NSAIDs or local anaesthetics were administered but responded to the effects of N-methyl D-aspartate (NMDA) receptor antagonists by moderately reducing mechanical hyperalgesia. CONCLUSIONS Based on pharmacological sensitivity, the UVB model adequately reflects inflammatory pain and was sensitive to NSAIDs and opioids. Findings from the capsaicin and burn models raised questions about the translatability of these models to the treatment of neuropathic pain. There is a need for a reproducible and predictive model of neuropathic pain, either in healthy subjects or in patients.
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Affiliation(s)
| | | | | | - Justin L Hay
- Centre for Human Drug Research (CHDR), Leiden, The Netherlands
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Hansen MS, Wetterslev J, Pipper CB, Asghar MS, Dahl JB. Is heat pain detection threshold associated with the area of secondary hyperalgesia following brief thermal sensitization? A study of healthy volunteers - design and detailed plan of analysis. BMC Anesthesiol 2016; 16:28. [PMID: 27246322 PMCID: PMC4888470 DOI: 10.1186/s12871-016-0193-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Accepted: 05/15/2016] [Indexed: 12/12/2022] Open
Abstract
Background Several factors are believed to influence the development and experience of pain. Human clinical pain models are central tools, in the investigation of basic physiologic pain responses, and can be applied in patients as well as in healthy volunteers. Each clinical pain model investigates different aspects of the human pain response. Brief thermal sensitization induces a mild burn injury, resulting in development of primary hyperalgesia at the site of stimulation, and secondary hyperalgesia surrounding the site of stimulation. Central sensitization is believed to play an important role in the development of secondary hyperalgesia; however, a possible association of secondary hyperalgesia following brief thermal sensitization and other heat pain models remains unknown. Our aim with this study is to investigate how close the heat pain detection threshold is associated with the size of the area of secondary hyperalgesia induced by the clinical heat pain model: Brief thermal sensitization. Methods and design We aim to include 120 healthy participants. The participants will be tested on two separate study days with the following procedures: i) Brief thermal sensitization, ii) heat pain detection threshold and iii) pain during thermal stimulation. Additionally, the participants will be tested with the Pain Catastrophizing Scale and Hospital Anxiety and Depression Scale questionnaires. We conducted statistical simulations based on data from our previous study, to estimate an empirical power of 99.9 % with α of 0.05. We define that an R2 < 0.25 and predictive intervals larger than +/−150 cm2 are indications of a weak association. Discussion The area of secondary hyperalgesia may serve as a quantitative measure of the central sensitization induced by cutaneous heat stimulation, and thus may be a biomarker of an individual’s pain sensitivity. The number of studies investigating secondary hyperalgesia is growing; however basic knowledge of the physiologic aspects of secondary hyperalgesia in humans is still incomplete. We therefore find it interesting to investigate if HPDT, a known quantitative sensory test, is associated with areas of secondary hyperalgesia following brief thermal sensitization Trial registration Clinicaltrials.gov (Identifier: NCT02527395). Danish Research Ethics Committee (Identifier: H-8-2014-012). Danish Data Protection Agency (Identifier: 30-1436). Electronic supplementary material The online version of this article (doi:10.1186/s12871-016-0193-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Morten Sejer Hansen
- Department of Anaesthesiology, 4231, Centre of Head and Orthopaedics, Rigshospitalet, Blegdamsvej 9, Copenhagen, 2100, Denmark.
| | - Jørn Wetterslev
- Copenhagen Trial Unit, Centre for Clinical Intervention Research, dep. 7812, Blegdamsvej 9, Copenhagen, 2100, Denmark
| | - Christian Bressen Pipper
- Section of Biostatistics, Faculty of Health, Copenhagen University, Øster Farigmagsgade 5, Copenhagen, 1014, Denmark
| | - Mohammad Sohail Asghar
- Department of Anaesthesiology, 4231, Centre of Head and Orthopaedics, Rigshospitalet, Blegdamsvej 9, Copenhagen, 2100, Denmark
| | - Jørgen Berg Dahl
- Department of Anaesthesiology, dep. Z, Bispebjerg Hospital, Bispebjerg Bakke 23, Copenhagen, 2400, Denmark
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Hansen MS, Wetterslev J, Pipper CB, Østervig R, Asghar MS, Dahl JB. The Area of Secondary Hyperalgesia following Heat Stimulation in Healthy Male Volunteers: Inter- and Intra-Individual Variance and Reproducibility. PLoS One 2016; 11:e0155284. [PMID: 27167119 PMCID: PMC4864410 DOI: 10.1371/journal.pone.0155284] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 03/29/2016] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION Clinical pain models can be applied when investigating basic physiologic pain responses in healthy volunteers. Several pain models exist; however, only few have been adequately validated. Our primary aim with this prospective study was to investigate the intra- and inter-individual variation in secondary hyperalgesia elicited by brief thermal sensitization (45°C for 3 min) in healthy volunteers. MATERIAL AND METHODS Fifty healthy volunteers were included. Areas of secondary hyperalgesia following brief thermal sensitization were investigated by 2 observers on 4 experimental days, with a minimum interval of 7 days. Additionally, heat pain detection threshold and pain during thermal stimulation (45°C for 1 min.), and the psychological tests Pain Catastrophizing Scale and Hospital Anxiety and Depression Score were applied. RESULTS For areas of secondary hyperalgesia, an intra-observer intra-person correlation of 0.85, 95% CI [0.78, 0.90], an intra-observer inter-person correlation of 0.03, 95% CI [0.00, 0.16], and a coefficient of variation of 0.17, 95% CI [0.14, 0.21] was demonstrated. Four percent of the study population had areas of secondary hyperalgesia both below the 1st and above the 3rd quartile considering all included participants. Heat pain detection threshold predicted area of secondary hyperalgesia with an adjusted R2 of 0.20 (P = 0.0006). CONCLUSIONS We have demonstrated a low intra-individual, and a high inter-individual variation in thermally induced secondary hyperalgesia. We conclude that brief thermal sensitization produce secondary hyperalgesia with a high level of reproducibility, which can be applied to investigate different phenotypes related to secondary hyperalgesia in healthy volunteers. TRIAL REGISTRATION clinicaltrials.gov NCT02166164.
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Affiliation(s)
- Morten Sejer Hansen
- Department of Anesthesiology 4231, Centre of Head and Orthopedics, Rigshospitalet, Copenhagen, Denmark
- * E-mail:
| | - Jørn Wetterslev
- Department 7812, Copenhagen Trial Unit, Centre for Clinical Intervention Research, Copenhagen, Denmark
| | | | - Rebecca Østervig
- Department of Anesthesiology 4231, Centre of Head and Orthopedics, Rigshospitalet, Copenhagen, Denmark
| | - Mohammad Sohail Asghar
- Department of Anesthesiology 4231, Centre of Head and Orthopedics, Rigshospitalet, Copenhagen, Denmark
| | - Jørgen Berg Dahl
- Department of Anesthesiology, Bispebjerg and Frederiksberg Hospitals, Copenhagen, Denmark
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8
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Ringsted TK, Enghuus C, Petersen MA, Werner MU. Demarcation of secondary hyperalgesia zones: Punctate stimulation pressure matters. J Neurosci Methods 2015; 256:74-81. [PMID: 26310180 DOI: 10.1016/j.jneumeth.2015.08.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 08/16/2015] [Accepted: 08/18/2015] [Indexed: 01/30/2023]
Abstract
BACKGROUND Secondary hyperalgesia is increased sensitivity in normal tissue near an injury, and it is a measure of central sensitization reflecting injury-related effects on the CNS. Secondary hyperalgesia areas (SHAs), usually assessed by polyamide monofilaments, are important outcomes in studies of analgesic drug effects in humans. However, since the methods applied in demarcating the secondary hyperalgesia zone seem inconsistent across studies, we examined the effect of a standardized approach upon the measurement of SHA following a first degree burn injury (BI). NEW METHOD The study was a two-observer, test-retest study with the two sessions separated by 6wk. An observer-blinded design adjusted to examine day-to-day and observer-to-observer variability in SHA was used. In 23 healthy volunteers (12 females/11 males) a BI was induced by a contact thermode (47.0°C, 420s, 2.5×5.0cm(2)). The SHA, demarcated by polyamide monofilaments (bending force: 0.2, 69 and 2569mN) and a "weighted-pin" stimulator (512mN), were assessed 45 to 75min after each BI. RESULTS A random effect, linear mixed model demonstrated a logarithmic correlation between elicited skin pressures (mN/mm(2)) and the SHAs (P<0.0001). No day-to-day or observer-to-observer differences in SHAs were observed. Intraclass correlation coefficients, in the range of 0.51 to 0.84, indicated a moderate to almost perfect reliability between observers. COMPARISON WITH EXISTING METHODS No standardized approach in SHA-assessment has hitherto been presented. CONCLUSIONS This is the first study to demonstrate that demarcation of secondary hyperalgesia zones depends on the developed pressure of the punctate stimulator used.
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Affiliation(s)
- Thomas K Ringsted
- Neuroscience Center, Rigshospitalet, Copenhagen University Hospitals, Multidisciplinary Pain Center 7612, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark.
| | - Casper Enghuus
- Neuroscience Center, Rigshospitalet, Copenhagen University Hospitals, Multidisciplinary Pain Center 7612, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Morten A Petersen
- Research Unit, Department of Palliative Care, Bispebjerg Hospital, Copenhagen University Hospitals, Copenhagen, Denmark
| | - Mads U Werner
- Neuroscience Center, Rigshospitalet, Copenhagen University Hospitals, Multidisciplinary Pain Center 7612, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
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9
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Peppin JF, Albrecht PJ, Argoff C, Gustorff B, Pappagallo M, Rice FL, Wallace MS. Skin Matters: A Review of Topical Treatments for Chronic Pain. Part One: Skin Physiology and Delivery Systems. Pain Ther 2015; 4:17-32. [PMID: 25627665 PMCID: PMC4470967 DOI: 10.1007/s40122-015-0031-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Indexed: 12/16/2022] Open
Abstract
Chronic pain is a complex disorder with multiple etiologies for which the pathologic mechanisms are still largely unknown, making effective treatment a difficult clinical task. Achieving pain relief along with improved function and quality of life is the primary goal of pain clinicians; however, most patients and healthcare professionals consider 30% pain improvement to be clinically significant—a success level that would be unacceptable in other areas of medicine. Furthermore, patients with chronic pain frequently have multiple comorbidities, including depression and sleep apnea, and most have seen several physicians prior to being seen by a pain specialist, have more than three specific pain generators, and are taking multiple medications. The addition of further oral medications to control pain increases the risk of drug–drug interactions and side effects. However, topical analgesics have the advantage of local application with limited systemic levels of drug. Topical therapies benefit from reduced side effects, lower risk of drug–drug interactions, better patient acceptability/compliance, and improved tolerability. This two-part paper is a review of topical analgesics and their potential role in the treatment of chronic pain.
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Affiliation(s)
- John F Peppin
- Center for Bioethics Pain Management and Medicine, St. Louis, MO, USA,
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10
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Cavallone LF, Frey K, Montana MC, Joyal J, Regina KJ, Petersen KL, Gereau RW. Reproducibility of the heat/capsaicin skin sensitization model in healthy volunteers. J Pain Res 2013; 6:771-84. [PMID: 24232380 PMCID: PMC3827105 DOI: 10.2147/jpr.s53437] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Introduction Heat/capsaicin skin sensitization is a well-characterized human experimental model to induce hyperalgesia and allodynia. Using this model, gabapentin, among other drugs, was shown to significantly reduce cutaneous hyperalgesia compared to placebo. Since the larger thermal probes used in the original studies to produce heat sensitization are now commercially unavailable, we decided to assess whether previous findings could be replicated with a currently available smaller probe (heated area 9 cm2 versus 12.5–15.7 cm2). Study design and methods After Institutional Review Board approval, 15 adult healthy volunteers participated in two study sessions, scheduled 1 week apart (Part A). In both sessions, subjects were exposed to the heat/capsaicin cutaneous sensitization model. Areas of hypersensitivity to brush stroke and von Frey (VF) filament stimulation were measured at baseline and after rekindling of skin sensitization. Another group of 15 volunteers was exposed to an identical schedule and set of sensitization procedures, but, in each session, received either gabapentin or placebo (Part B). Results Unlike previous reports, a similar reduction of areas of hyperalgesia was observed in all groups/sessions. Fading of areas of hyperalgesia over time was observed in Part A. In Part B, there was no difference in area reduction after gabapentin compared to placebo. Conclusion When using smaller thermal probes than originally proposed, modifications of other parameters of sensitization and/or rekindling process may be needed to allow the heat/capsaicin sensitization protocol to be used as initially intended. Standardization and validation of experimental pain models is critical to the advancement of translational pain research.
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Affiliation(s)
- Laura F Cavallone
- Department of Anesthesiology, Washington University in St Louis, School of Medicine, St Louis, MO, USA
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11
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Werner MU, Petersen KL, Rowbotham MC, Dahl JB. Healthy volunteers can be phenotyped using cutaneous sensitization pain models. PLoS One 2013; 8:e62733. [PMID: 23671631 PMCID: PMC3650051 DOI: 10.1371/journal.pone.0062733] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2013] [Accepted: 03/25/2013] [Indexed: 11/24/2022] Open
Abstract
Background Human experimental pain models leading to development of secondary hyperalgesia are used to estimate efficacy of analgesics and antihyperalgesics. The ability to develop an area of secondary hyperalgesia varies substantially between subjects, but little is known about the agreement following repeated measurements. The aim of this study was to determine if the areas of secondary hyperalgesia were consistently robust to be useful for phenotyping subjects, based on their pattern of sensitization by the heat pain models. Methods We performed post-hoc analyses of 10 completed healthy volunteer studies (n = 342 [409 repeated measurements]). Three different models were used to induce secondary hyperalgesia to monofilament stimulation: the heat/capsaicin sensitization (H/C), the brief thermal sensitization (BTS), and the burn injury (BI) models. Three studies included both the H/C and BTS models. Results Within-subject compared to between-subject variability was low, and there was substantial strength of agreement between repeated induction-sessions in most studies. The intraclass correlation coefficient (ICC) improved little with repeated testing beyond two sessions. There was good agreement in categorizing subjects into ‘small area’ (1st quartile [<25%]) and ‘large area’ (4th quartile [>75%]) responders: 56–76% of subjects consistently fell into same ‘small-area’ or ‘large-area’ category on two consecutive study days. There was moderate to substantial agreement between the areas of secondary hyperalgesia induced on the same day using the H/C (forearm) and BTS (thigh) models. Conclusion Secondary hyperalgesia induced by experimental heat pain models seem a consistent measure of sensitization in pharmacodynamic and physiological research. The analysis indicates that healthy volunteers can be phenotyped based on their pattern of sensitization by the heat [and heat plus capsaicin] pain models.
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Affiliation(s)
- Mads U Werner
- Multidisciplinary Pain Center, Neuroscience Center, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
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Hayashida M, Fukuda KI, Fukunaga A. Clinical application of adenosine and ATP for pain control. J Anesth 2005; 19:225-35. [PMID: 16032451 DOI: 10.1007/s00540-005-0310-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2004] [Accepted: 02/02/2005] [Indexed: 11/24/2022]
Abstract
This review summarizes clinical application of adenosine and adenosine 5'-triphosphate (ATP) in pain conditions. Investigations have been performed in patients with acute perioperative pain or chronic neuropathic pain treated with intravenous adenosine or ATP, or intrathecal adenosine. Characteristic central adenosine A1 receptor-mediated pain-relieving effects have been observed after intravenous adenosine infusion in human inflammation/sensitization pain models and in patients with chronic neuropathic pain. Adenosine compounds, in low doses, can reduce allodynia/hyperalgesia more consistently than spontaneous pain, suggesting that these compounds affect neuronal pathophysiological mechanisms involved in central sensitization. Such pain-relieving effects, which are mostly mediated via central adenosine A1 receptor activation, have a slow onset and long duration of action, lasting usually for hours or days and occasionally for months. With acute perioperative pain, treatment with a low-dose infusion of adenosine compounds and the A1 receptor-mediated central antisensitization mechanisms may play only a minor part in the total perioperative pain experience. By administering sufficient doses of adenosine compounds during surgery, however, significant and long-lasting perioperative pain relief can be achieved via central A1 receptor-mediated antinociceptive/analgesic actions as well as via peripheral A2a or A3 receptor-mediated antiinflammatory actions. Thus, adenosine compounds have significant potential for alleviating various types of pain.
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Affiliation(s)
- Masakazu Hayashida
- Surgical Center Research Hospital, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shiroganedai, Minato-ku, Tokyo, 108-8639, Japan
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