1
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Liu W, Luo Y, Song W, Dan H, Li L, Zhou D, You P. Angelica Yinzi Alleviates Pruritus-Related Atopic Dermatitis through Skin Repair, Antioxidation, and Balancing Peripheral μ- and κ-opioid Receptors. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE : ECAM 2023; 2023:6058951. [PMID: 37790739 PMCID: PMC10545464 DOI: 10.1155/2023/6058951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 05/10/2022] [Indexed: 10/05/2023]
Abstract
Background Angelica Yinzi (AYZ) is a Chinese traditional herbal formula reported to attenuate itches and inflammation caused by atopic dermatitis (AD). However, the underlying mechanism of AYZ in the attenuation of itchiness and inflammation remains unknown. Objective This study investigated the mechanism of AYZ in reducing itchiness in mice with 1-chloro-2,4-dinitrobenzene- (DNCB-)-induced atopic dermatitis. Methods Hematoxylin and eosin (H&E) and toluidine blue staining were used to evaluate pathological changes in skin tissue, while an enzyme-linked immunosorbent assay (ELISA) was used to assess the cytokine levels in the skin. After that, qRT-PCR was performed to determine the mRNA levels of cytokines in the skin. Immunofluorescence and western blotting analysis were further used to assess µ-opioid receptor (MOR) expression and immunohistochemistry to assess the p-ERK, p-AKT, and κ-opioid receptor (KOR). Results The AYZ treatment alleviated the AD clinical symptoms, including decreasing the scratching frequency, the ear thickness, and the infiltration of mast cells, lymphocytes, inflammatory cells, and mononuclear cells. In addition, AYZ inhibited the expression of interleukin (IL)-13, thymic stromal lymphopoietin (TSLP), and reduced neuraminidase (NA), corticotropin-releasing factor (CRF), and reactive oxygen species (ROS) expression. Markers involved in itches, such as p-ERK and p-AKT, were significantly downregulated following AYZ treatment. Besides, AYZ significantly increased MOR expression and downregulated KOR in the epidermis and spinal cord. Conclusion Our findings imply that AYZ ameliorates pruritus-related AD through skin repair, antioxidation, and balancing peripheral MOR and KOR. The findings in this study lay a theoretical foundation for the control mechanism of peripheral itch.
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Affiliation(s)
- Wei Liu
- Beijing Key Laboratory of Molecular Pharmaceutics and New Drug Delivery Systems, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
- Research Center, Mayinglong Pharmaceutical Group Co. Ltd., Wuhan 430060, Hubei, China
| | - Yang Luo
- Hubei Key Laboratory of Resources and Chemistry of Chinese Medicine, Hubei University of Chinese Medicine, Wuhan, Hubei 430065, China
| | - Wanci Song
- Hubei Key Laboratory of Resources and Chemistry of Chinese Medicine, Hubei University of Chinese Medicine, Wuhan, Hubei 430065, China
| | - Hanxiong Dan
- Hubei Key Laboratory of Resources and Chemistry of Chinese Medicine, Hubei University of Chinese Medicine, Wuhan, Hubei 430065, China
| | - Li Li
- Department of Pharmacy, Wuhan Hospital of Traditional Chinese Medicine, Wuhan, Hubei 430014, China
| | - Daonian Zhou
- Research Center, Mayinglong Pharmaceutical Group Co. Ltd., Wuhan 430060, Hubei, China
| | - Pengtao You
- Hubei Key Laboratory of Resources and Chemistry of Chinese Medicine, Hubei University of Chinese Medicine, Wuhan, Hubei 430065, China
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2
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Boyle KA, Polgar E, Gutierrez-Mecinas M, Dickie AC, Cooper AH, Bell AM, Jumolea E, Casas-Benito A, Watanabe M, Hughes DI, Weir GA, Riddell JS, Todd AJ. Neuropeptide Y-expressing dorsal horn inhibitory interneurons gate spinal pain and itch signalling. eLife 2023; 12:RP86633. [PMID: 37490401 PMCID: PMC10392120 DOI: 10.7554/elife.86633] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2023] Open
Abstract
Somatosensory information is processed by a complex network of interneurons in the spinal dorsal horn. It has been reported that inhibitory interneurons that express neuropeptide Y (NPY), either permanently or during development, suppress mechanical itch, with no effect on pain. Here, we investigate the role of interneurons that continue to express NPY (NPY-INs) in the adult mouse spinal cord. We find that chemogenetic activation of NPY-INs reduces behaviours associated with acute pain and pruritogen-evoked itch, whereas silencing them causes exaggerated itch responses that depend on cells expressing the gastrin-releasing peptide receptor. As predicted by our previous studies, silencing of another population of inhibitory interneurons (those expressing dynorphin) also increases itch, but to a lesser extent. Importantly, NPY-IN activation also reduces behavioural signs of inflammatory and neuropathic pain. These results demonstrate that NPY-INs gate pain and itch transmission at the spinal level, and therefore represent a potential treatment target for pathological pain and itch.
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Affiliation(s)
- Kieran A Boyle
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Erika Polgar
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Maria Gutierrez-Mecinas
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Allen C Dickie
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Andrew H Cooper
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Andrew M Bell
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Evelline Jumolea
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Adrian Casas-Benito
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University School of Medicine, Sapporo, Japan
| | - David I Hughes
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Gregory A Weir
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - John S Riddell
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Andrew J Todd
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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3
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Abstract
The opioid peptides and their receptors have been linked to multiple key biological processes in the nervous system. Here we review the functions of the kappa opioid receptor (KOR) and its endogenous agonists dynorphins (Goldstein A, Tachibana S, Lowney LI, Hunkapiller M, Hood L, Proc Natl Acad Sci U S A 76:6666-6670, 1979) in modulating itch and pain (nociception). Specifically, we discuss their roles relative to recent findings that tell us more about the cells and circuits which are impacted by this opioid and its receptor and present reanalysis of single-cell sequencing data showing the expression profiles of these molecules. Since the KOR is relatively specifically activated by peptides derived from the prodynorphin gene and other opioid peptides that show lower affinities, this will be the only interactions we consider (Chavkin C, Goldstein A, Nature 291:591-593, 1981; Chavkin C, James IF, Goldstein A, Science 215:413-415, 1982), although it was noted that at higher doses peptides other than dynorphins might stimulate KOR (Lai J, Luo MC, Chen Q, Ma S, Gardell LR, Ossipov MH, Porreca F, Nat Neurosci 9:1534-1540, 2006). This review has been organized based on anatomy with each section describing the effect of the kappa opioid system in a specific location but let us not forget that most of these circuits are interconnected and are therefore interdependent.
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Affiliation(s)
- Pang-Yen Tseng
- Molecular Genetics Section, National Institute of Dental and Craniofacial Research/NIH, Bethesda, MD, USA
| | - Mark A Hoon
- Molecular Genetics Section, National Institute of Dental and Craniofacial Research/NIH, Bethesda, MD, USA.
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4
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Misery L, Brenaut E, Pierre O, Le Garrec R, Gouin O, Lebonvallet N, Abasq-Thomas C, Talagas M, Le Gall-Ianotto C, Besner-Morin C, Fluhr JW, Leven C. Chronic itch: emerging treatments following new research concepts. Br J Pharmacol 2021; 178:4775-4791. [PMID: 34463358 DOI: 10.1111/bph.15672] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 08/20/2021] [Accepted: 08/24/2021] [Indexed: 11/29/2022] Open
Abstract
Until recently, itch pathophysiology was poorly understood and treatments were poorly effective in relieving itch. Current progress in our knowledge of the itch processing, the numerous mediators and receptors involved has led to a large variety of possible therapeutic pathways. Currently, inhibitors of IL-31, IL-4/13, NK1 receptors, opioids and cannabinoids, JAK, PDE4 or TRP are the main compounds involved in clinical trials. However, many new targets, such as Mas-related GPCRs and unexpected new pathways need to be also explored.
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Affiliation(s)
- Laurent Misery
- LIEN, Univ Brest, Brest, France.,Department of Dermatology, University Hospital of Brest, Brest, France
| | - Emilie Brenaut
- LIEN, Univ Brest, Brest, France.,Department of Dermatology, University Hospital of Brest, Brest, France
| | | | | | - Olivier Gouin
- LIEN, Univ Brest, Brest, France.,INSERM UMR 1163, Laboratory of Genetic Skin Diseases, Imagine Institute, Paris, France.,University of Paris, Paris, France
| | | | - Claire Abasq-Thomas
- LIEN, Univ Brest, Brest, France.,Department of Dermatology, University Hospital of Brest, Brest, France
| | - Matthieu Talagas
- LIEN, Univ Brest, Brest, France.,Department of Dermatology, University Hospital of Brest, Brest, France
| | | | - Catherine Besner-Morin
- LIEN, Univ Brest, Brest, France.,Department of Dermatology, University Hospital of Brest, Brest, France.,Division of Dermatology, McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, Canada
| | - Joachim W Fluhr
- LIEN, Univ Brest, Brest, France.,Department of Dermatology, University Hospital of Brest, Brest, France.,Department of Dermatology, Charité Universitätsmedizin, Berlin, Germany
| | - Cyril Leven
- LIEN, Univ Brest, Brest, France.,EA3878, FCRIN INNOVTE, groupe d'étude thrombose Bretagne Occidentale, Brest, France.,Department of Biochemistry and Pharmaco-Toxicology, University Hospital of Brest, Brest, France
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5
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Mishra SK, Wheeler JJ, Pitake S, Ding H, Jiang C, Fukuyama T, Paps JS, Ralph P, Coyne J, Parkington M, DeBrecht J, Ehrhardt-Humbert LC, Cruse GP, Bäumer W, Ji RR, Ko MC, Olivry T. Periostin Activation of Integrin Receptors on Sensory Neurons Induces Allergic Itch. Cell Rep 2021; 31:107472. [PMID: 32268102 PMCID: PMC9210348 DOI: 10.1016/j.celrep.2020.03.036] [Citation(s) in RCA: 70] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 02/04/2020] [Accepted: 03/11/2020] [Indexed: 12/15/2022] Open
Abstract
Chronic allergic itch is a common symptom affecting millions of people and animals, but its pathogenesis is not fully explained. Herein, we show that periostin, abundantly expressed in the skin of patients with atopic dermatitis (AD), induces itch in mice, dogs, and monkeys. We identify the integrin αVβ3 expressed on a subset of sensory neurons as the periostin receptor. Using pharmacological and genetic approaches, we inhibited the function of neuronal integrin αVβ3, which significantly reduces periostin-induced itch in mice. Furthermore, we show that the cytokine TSLP, the application of AD-causing MC903 (calcipotriol), and house dust mites all induce periostin secretion. Finally, we establish that the JAK/STAT pathway is a key regulator of periostin secretion in keratinocytes. Altogether, our results identify a TSLP-periostin reciprocal activation loop that links the skin to the spinal cord via peripheral sensory neurons, and we characterize the non-canonical functional role of an integrin in itch. Mishra et al. demonstrate periostin-induced itch in mice, dogs, and monkeys and identify the integrin αVβ3 as the periostin neuronal receptor. They find that keratinocytes release periostin in response to TSLP, thus identifying a possible reciprocal vicious circle implicating the cytokine TSLP and periostin in chronic allergic itch.
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Affiliation(s)
- Santosh K Mishra
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA; Comparative Medicine Institute, North Carolina State University, Raleigh, NC, USA; The WM Keck Behavioral Center, North Carolina State University, Raleigh, NC, USA; Program in Genetics, North Carolina State University, Raleigh, NC, USA.
| | - Joshua J Wheeler
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA; Comparative Medicine Institute, North Carolina State University, Raleigh, NC, USA
| | - Saumitra Pitake
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Huiping Ding
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | | | - Tomoki Fukuyama
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Judy S Paps
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Patrick Ralph
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Jacob Coyne
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Michelle Parkington
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Jennifer DeBrecht
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Lauren C Ehrhardt-Humbert
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Glenn P Cruse
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA; Comparative Medicine Institute, North Carolina State University, Raleigh, NC, USA
| | - Wolfgang Bäumer
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA; Institute of Pharmacology and Toxicology, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | | | - Mei-Chuan Ko
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Thierry Olivry
- Comparative Medicine Institute, North Carolina State University, Raleigh, NC, USA; Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
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6
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Ständer S, Schmelz M. [Neuropathic pruritus]. Schmerz 2020; 34:525-535. [PMID: 33025226 DOI: 10.1007/s00482-020-00502-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 07/14/2020] [Accepted: 07/15/2020] [Indexed: 11/26/2022]
Abstract
In the past 10 years specific pathways for pruritus have been characterized on a cellular and molecular level but their exact role in the pathophysiology of neuropathic pruritus remains unclear. This also applies to the question which of the competing theories for pruritus, e.g. specificity, temporal/spatial pattern or intensity, would best apply. While experimental trials on mice have mostly confirmed the theory of specificity, the results on humans indicate a role of spatial and temporal patterns. The skin innervation is greatly reduced by the neuropathy and could provide a "spatial contrast pattern" and the axotomy could induce a de novo expression of gastrin-releasing peptide (GRP) in primarily afferent nociceptors and thus modulate spinal pruritus processing. In addition, the overlap of pruritus and pain in neuropathy patients complicates the direct translation from animal experiments and requires collaboration at the clinical level between pain medicine and dermatology.
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Affiliation(s)
- Sonja Ständer
- Kompetenzzentrum Chronischer Pruritus, Universitätsklinikum Münster, Münster, Deutschland
| | - Martin Schmelz
- Experimentelle Schmerzforschung, MCTN, Medizinische Fakultät Mannheim, Universität Heidelberg, Ludolf-Krehl-Str. 13-17, 68167, Mannheim, Deutschland.
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7
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Schmelz M. [Pruritus-a long journey from neurophysiology to the clinic]. Hautarzt 2020; 71:487-492. [PMID: 32468292 DOI: 10.1007/s00105-020-04614-2] [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] [Indexed: 11/26/2022]
Abstract
BACKGROUND The mutual exchange of results between basic sciences and clinical research as well as their translation into practice, also with regard to chronic pruritus, is currently to be seen as an ambition or hope rather than established practice. OBJECTIVE In view of the rapid developments in the field of neurophysiological basics of pruritus, the aim is to clarify how these new concepts can be brought in line with clinical understanding. MATERIALS AND METHODS A review is provided. RESULTS After the peripheral and spinal processing pathways for pruritus in the mouse were characterized with molecular markers, we are currently working on the translation of this information to the only functionally defined nerve fiber classes in humans. However, it is still unclear whether these processing pathways are crucial for the explanation of chronic pruritus in patients, since inflammation or neuropathy can significantly alter nerve populations and neuronal networks. Therefore, molecular target structures, which have emerged from results of basic research, need to be verified in patients. The gold standard, however, remains the patient with clinical observation and testing. Specific stimulation methods from neurophysiology can help to test hypotheses from basic research directly on patients, while also providing impulses for further development of research concepts. CONCLUSIONS Translation in medical research is now perceived by many researchers as a hackneyed buzzword. In the field of pruritus research, however, the exchange of results and concepts based on the mutual appreciation of expertise appears attractive, highly relevant, and promising.
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Affiliation(s)
- M Schmelz
- Abteilung Experimentelle Schmerzforschung, MCTN, Med. Fakultät Mannheim, Universität Heidelberg, Ludolf-Krehl-Str. 13-17, 68167, Mannheim, Deutschland.
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8
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Huang Z, Zhou X, Zhang J, Mai CL, Mai JZ, Liu C, Zhang H, Liu XG. Bulleyaconitine A Inhibits Itch and Itch Sensitization Induced by Histamine and Chloroquine. Neuroscience 2020; 429:68-77. [DOI: 10.1016/j.neuroscience.2019.12.048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 12/11/2019] [Accepted: 12/31/2019] [Indexed: 02/07/2023]
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9
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Meng J, Chen W, Wang J. Interventions in the B-type natriuretic peptide signalling pathway as a means of controlling chronic itch. Br J Pharmacol 2020; 177:1025-1040. [PMID: 31877230 DOI: 10.1111/bph.14952] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 11/08/2019] [Accepted: 11/19/2019] [Indexed: 12/22/2022] Open
Abstract
Chronic itch poses major health care and economic burdens worldwide. In 2013, B-type natriuretic peptide (BNP) was identified as an itch-selective neuropeptide and shown to be both necessary and sufficient to produce itch behaviour in mice. Since then, mechanistic studies of itch have increased, not only at central levels of the spinal relay of itch signalling but also in the periphery and skin. In this review, we have critically analysed recent findings from complementary pharmacological and physiological approaches, combined with genetic strategies to examine the role of BNP in itch transduction and modulation of other pruritic proteins. Additionally, potential targets and possible strategies against BNP signalling are discussed for developing novel therapeutics in itch. Overall, we aim to provide insights into drug development by altering BNP signalling to modulate disease symptoms in chronic itch, including conditions for which no approved treatment exists.
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Affiliation(s)
- Jianghui Meng
- School of Life Sciences, Henan University, Henan, China.,National Institute for Cellular Biotechnology, Dublin City University, Dublin, Ireland.,School of Biotechnology, Faculty of Science and Health, Dublin City University, Dublin, Ireland
| | - Weiwei Chen
- School of Life Sciences, Henan University, Henan, China
| | - Jiafu Wang
- School of Life Sciences, Henan University, Henan, China.,School of Biotechnology, Faculty of Science and Health, Dublin City University, Dublin, Ireland
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10
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Abstract
Itching can result from activity of specialized primary afferent neurons (“pruriceptors”) that have been shown to express certain molecular markers such as B-type natriuretic peptide and several members of the Mrgpr-family in rodents. On the other hand, neurons involved in pain processing (“nociceptors”) can also provoke itching when the activation site is restricted to an isolated tiny spot within the epidermis. Individuals classified as having sensitive skin report increased itching and pain sensations upon weak external stimuli that are not painful or itchy in the control group. Numerous possible factors could contribute to sensitive skin along the pathway of transduction of the external stimuli into peripheral neuronal signals, followed by neuronal processing, finally resulting in the perception: (a) reduced local protective factors leading to impaired skin barrier function, (b) increased production of excitatory skin mediators, (c) sensitized peripheral neurons, (d) facilitated spinal and central processing, and (e) reduced descending inhibition from the central nervous system. For all of those pathophysiological mechanisms there are clinical examples such as atopic dermatitis (a,b,c), neuropathic itching (c,e), and restless leg syndrome (d,e). However, none of these factors have been directly linked to the occurrence of sensitive skin. Moreover, individuals reporting sensitive skin are heterogeneous and a subpopulation with defined pathophysiology has not yet been identified. Given that the condition is reported in about 50% of women, and thereby includes many healthy individuals, it appears problematic to assign a definitive pathophysiological mechanism to it.
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Affiliation(s)
- Martin Schmelz
- Department Experimental Pain Research, CBTM, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
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11
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Abstract
Neuropathic itch is clinically important but has received much less attention as compared to neuropathic pain. In the past decade, itch-specific pathways have been characterized on a cellular and molecular level, but their exact role in the pathophysiology of neuropathic itch is still unclear. Traditionally, mutually exclusive theories for itch such as labeled line, temporal/spatial pattern, or intensity theory have been proposed, and experimental studies in mice mainly favor the specificity theory of itch. By contrast, results in humans also suggest a role for spatial and temporal patterns in neuropathic itch. Rarefication of skin innervation in neuropathy could provide a "spatial contrast" discharge pattern, and axotomy could induce de novo expression of the itch-specific spinal neuropeptide, gastrin-releasing peptide, in primary afferent nociceptors, thereby modulating itch processing in the dorsal horn. Thus, clinical neuropathy may generate itch by changes in the spatial and temporal discharge patterns of nociceptors, hijacking the labeled line processing of itch and abandoning the canonical scheme of mutual exclusive itch theories. Moreover, the overlap between itch and pain symptoms in neuropathy patients complicates direct translation from animal experiments and, on a clinical level, necessitates collaboration between medical specialities, such as dermatologists, anesthesiologists, and neurologists.
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12
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13
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Stull C, Lavery MJ, Yosipovitch G. Advances in therapeutic strategies for the treatment of pruritus. Expert Opin Pharmacother 2015; 17:671-87. [DOI: 10.1517/14656566.2016.1127355] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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