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Merighi A. Brain-Derived Neurotrophic Factor, Nociception, and Pain. Biomolecules 2024; 14:539. [PMID: 38785946 PMCID: PMC11118093 DOI: 10.3390/biom14050539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 04/26/2024] [Accepted: 04/26/2024] [Indexed: 05/25/2024] Open
Abstract
This article examines the involvement of the brain-derived neurotrophic factor (BDNF) in the control of nociception and pain. BDNF, a neurotrophin known for its essential role in neuronal survival and plasticity, has garnered significant attention for its potential implications as a modulator of synaptic transmission. This comprehensive review aims to provide insights into the multifaceted interactions between BDNF and pain pathways, encompassing both physiological and pathological pain conditions. I delve into the molecular mechanisms underlying BDNF's involvement in pain processing and discuss potential therapeutic applications of BDNF and its mimetics in managing pain. Furthermore, I highlight recent advancements and challenges in translating BDNF-related research into clinical practice.
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Affiliation(s)
- Adalberto Merighi
- Department of Veterinary Sciences, University of Turin, 10095 Turin, Italy
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2
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Kaneko T, Oura A, Imai Y, Kusumoto-Yoshida I, Kanekura T, Okuno H, Kuwaki T, Kashiwadani H. Orexin neurons play contrasting roles in itch and pain neural processing via projecting to the periaqueductal gray. Commun Biol 2024; 7:290. [PMID: 38459114 PMCID: PMC10923787 DOI: 10.1038/s42003-024-05997-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 02/28/2024] [Indexed: 03/10/2024] Open
Abstract
Pain and itch are recognized as antagonistically regulated sensations; pain suppresses itch, whilst pain inhibition enhances itch. The neural mechanisms at the central nervous system (CNS) underlying these pain-itch interactions still need to be explored. Here, we revealed the contrasting role of orexin-producing neurons (ORX neurons) in the lateral hypothalamus (LH), which suppresses pain while enhancing itch neural processing, by applying optogenetics to the acute pruritus and pain model. We also revealed that the circuit of ORX neurons from LH to periaqueductal gray regions served in the contrasting modulation of itch and pain processing using optogenetic terminal inhibition techniques. Additionally, by using an atopic dermatitis model, we confirmed the involvement of ORX neurons in regulating chronic itch processing, which could lead to a novel therapeutic target for persistent pruritus in clinical settings. Our findings provide new insight into the mechanism of antagonistic regulation between pain and itch in the CNS.
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Affiliation(s)
- Tatsuroh Kaneko
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.
| | - Asuka Oura
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Yoshiki Imai
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Ikue Kusumoto-Yoshida
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Takuro Kanekura
- Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Hiroyuki Okuno
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Tomoyuki Kuwaki
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Hideki Kashiwadani
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.
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3
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Go EJ, Lee JY, Kim YH, Park CK. Site-Specific Transient Receptor Potential Channel Mechanisms and Their Characteristics for Targeted Chronic Itch Treatment. Biomolecules 2024; 14:107. [PMID: 38254707 PMCID: PMC10813675 DOI: 10.3390/biom14010107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 01/10/2024] [Accepted: 01/13/2024] [Indexed: 01/24/2024] Open
Abstract
Chronic itch is a debilitating condition with limited treatment options, severely affecting quality of life. The identification of pruriceptors has sparked a growing interest in the therapeutic potential of TRP channels in the context of itch. In this regard, we provided a comprehensive overview of the site-specific expression of TRP channels and their associated functions in response to a range of pruritogens. Although several potent antipruritic compounds that target specific TRP channels have been developed and have demonstrated efficacy in various chronic itch conditions through experimental means, a more thorough understanding of the potential for adverse effects or interactions with other TRP channels or GPCRs is necessary to develop novel and selective therapeutics that target TRP channels for treating chronic itch. This review focuses on the mechanism of itch associated with TRP channels at specific sites, from the skin to the sensory neuron, with the aim of suggesting specific therapeutic targets for treating this condition.
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Affiliation(s)
- Eun Jin Go
- Gachon Pain Center and Department of Physiology, College of Medicine, Gachon University, Incheon 21999, Republic of Korea;
| | - Ji Yeon Lee
- Department of Anesthesiology and Pain Medicine, Gil Medical Center, Gachon University, Incheon 21565, Republic of Korea;
| | - Yong Ho Kim
- Gachon Pain Center and Department of Physiology, College of Medicine, Gachon University, Incheon 21999, Republic of Korea;
| | - Chul-Kyu Park
- Gachon Pain Center and Department of Physiology, College of Medicine, Gachon University, Incheon 21999, Republic of Korea;
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Becker JM, Van Ryckeghem DML, Van Damme S, Crombez G, Schoot Y, Wiers RWHJ, Rippe RCA, van Laarhoven AIM. Subliminal attentional bias modification training for itch. Front Med (Lausanne) 2023; 10:1104641. [PMID: 37275368 PMCID: PMC10232774 DOI: 10.3389/fmed.2023.1104641] [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: 11/21/2022] [Accepted: 05/02/2023] [Indexed: 06/07/2023] Open
Abstract
Introduction Itch is unpleasant and induces the urge to scratch. This is adaptive to remove the itch-inducing stimulus from the skin. Accordingly, itch draws attention to protect our bodily integrity. Recent studies investigated whether attention is preferentially drawn towards its location, i.e., attentional bias (AB), and also whether this bias could be changed in healthy individuals. So far, results are mixed concerning the existance of an attentional bias towards itch stimuli in healthy individuals as well as the impact of modifications. However, available studies have typically focused on conscious processing and might miss preconscious aspects of attention and potential biases at these stages. Methods This study included 117 healthy individuals who underwent a subliminal Attentional Bias Modification (ABM)- training for itch based on a dot-probe paradigm with itch- related pictures. Participants were randomly assigned to a training towards itch group, a training away from itch group and a control group. This was done by manipulating the itch-target congruency of the dot-probe task during a training block. Pre- and post-training assessments were regular dot-probe tasks. Exploratorily, also attentional inhibition, cognitive flexibility and itch-related cognitions were assessed. Lastly, participants received an itchy stimulus on the inner forearm before and after the ABM-training to assess potential effects on itch sensitivity. Results Results showed no AB towards itch across groups at baseline, i.e., pre-training, but an AB away from itch, hence, avoidance of itch, post-training. Further analyses showed that this effect was driven by an attentional bias away from itch in the control group, while there were no significant effects in the experimental groups. There was no effect on itch sensitivity. Conclusion These findings are in line with recent studies on conscious ABM-training for itch and pain that also did not find significant training effects. Therefore, it is suggested that the field of AB might need to reconsider the current assessment of AB. Moreover, AB is probably a dynamic process that is highly dependent on current itch-related goals and relevance of itch in a specific situation. This suggests that processes probably differ in patients with chronic itch and that also ABM-training might work differently in these populations. Clinical trial registration https://trialsearch.who.int/Trial2.aspx?TrialID=NTR7561, identifier NTR7561.
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Affiliation(s)
- Jennifer M. Becker
- Health, Medical and Neuropsychology, Faculty of Social and Behavioural Science, Institute of Psychology, Leiden University, Leiden, Netherlands
| | - Dimitri M. L. Van Ryckeghem
- Department of Experimental-Clinical and Health Psychology, Faculty of Psychology and Educational Sciences, Ghent University, Ghent, Belgium
- Section Experimental Health Psychology, Department of Clinical Psychological Science, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
- Research Unit INSIDE, Faculty of Humanities and Social Sciences, Institute of Health and Behavior, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Stefaan Van Damme
- Department of Experimental-Clinical and Health Psychology, Faculty of Psychology and Educational Sciences, Ghent University, Ghent, Belgium
| | - Geert Crombez
- Department of Experimental-Clinical and Health Psychology, Faculty of Psychology and Educational Sciences, Ghent University, Ghent, Belgium
| | - Yalou Schoot
- Health, Medical and Neuropsychology, Faculty of Social and Behavioural Science, Institute of Psychology, Leiden University, Leiden, Netherlands
| | - Reinout W. H. J. Wiers
- Addiction Development and Psychopathology (ADAPT) Laboratory, Department of Psychology, University of Amsterdam, Amsterdam, Netherlands
| | - Ralph C. A. Rippe
- Research Methods and Statistics, Faculty of Social and Behavioral Sciences, Institute of Education and Child Studies, Leiden University, Leiden, Netherlands
| | - Antoinette I. M. van Laarhoven
- Health, Medical and Neuropsychology, Faculty of Social and Behavioural Science, Institute of Psychology, Leiden University, Leiden, Netherlands
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Kaneko T, Kuwaki T. The opposite roles of orexin neurons in pain and itch neural processing. Peptides 2023; 160:170928. [PMID: 36566840 DOI: 10.1016/j.peptides.2022.170928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Revised: 12/17/2022] [Accepted: 12/20/2022] [Indexed: 12/24/2022]
Abstract
Pain and itch are antagonistically regulated sensations; pain suppresses itch, and inhibition of pain enhances itch. Understanding the central neural circuit of antagonistic regulation between pain and itch is required to develop new therapeutics better to manage these two feelings in a clinical situation. However, evidence of the neural mechanism underlying the pain-itch interaction in the central nervous system (CNS) is still insufficient. To pave the way for this research area, our laboratory has focused on orexin (ORX) producing neurons in the hypothalamus, which is known as a master switch that induces various defense responses when animals face a stressful environment. This review article summarized the previous evidence and our latest findings to argue the neural regulation between pain and itch and the bidirectional roles of ORX neurons in processing these two sensations. i.e., pain relief and itch exacerbation. Further, we discussed the possible neural circuit mechanism for the opposite controlling of pain and itch by ORX neurons. Focusing on the roles of ORX neurons would provide a new perspective to understand the antagonistic regulation of pain and itch in CNS.
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Affiliation(s)
- Tatsuroh Kaneko
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544, Japan.
| | - Tomoyuki Kuwaki
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544, Japan
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Van Loey NEE, de Jong AEE, Hofland HWC, van Laarhoven AIM. Role of burn severity and posttraumatic stress symptoms in the co-occurrence of itch and neuropathic pain after burns: A longitudinal study. Front Med (Lausanne) 2022; 9:997183. [PMID: 36314001 PMCID: PMC9596796 DOI: 10.3389/fmed.2022.997183] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 09/20/2022] [Indexed: 11/17/2022] Open
Abstract
Itch and pain are common after burns. Neuropathic mechanisms may underlie both modalities but remain not well-understood. This study aims to prospectively document neuropathic pain symptoms and to identify potential itch symptom profiles that differ regarding duration and co-occurrence with neuropathic pain which may inform underlying pathophysiological mechanisms and respond to different treatments. Adult burn survivors (n = 192) self-reported itch and neuropathic pain at 2 weeks post-discharge, 3, 6, 12, and 18 months post-burn. Based on the presence of itch and pain symptoms over time, participants were allocated to one itch profile: transient itch/pain, chronic itch, or chronic itch & pain. Profiles were compared on itch intensity over time using General Linear Modeling. Age, gender, burn severity, posttraumatic stress (PTS) symptoms and baseline itch intensity were examined as potential predictors of the profiles in a Multi-nominal regression analysis. Neuropathic pain occurred in 54% after discharge which decreased to 24% 18 months later. Itch intensity was highest in the chronic itch & pain profile. Compared to the transient itch profile, the chronic itch & pain profile was associated with higher burn severity and more PTS symptoms. Compared to the chronic itch profile, the chronic itch & pain profile was associated with more PTS symptoms. Findings suggest that biological and psycho-dermatological processes underlie both chronic neuropathic pain and itch processes in burn scars. Further research should elucidate the mechanisms underlying the different itch profiles, with specific focus on skin innervation and psychological factors.
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Affiliation(s)
- N. E. E. Van Loey
- Association of Dutch Burn Centres, Maasstad Hospital, Department of Burn Center, Rotterdam, Netherlands,Department of Clinical Psychology, Utrecht University, Utrecht, Netherlands,*Correspondence: N. E. E. Van Loey
| | | | - H. W. C. Hofland
- Association of Dutch Burn Centres, Maasstad Hospital, Department of Burn Center, Rotterdam, Netherlands
| | - A. I. M. van Laarhoven
- Health, Medical and Neuropsychology Unit, Faculty of Social and Behavioural Sciences, Leiden University, Leiden, Netherlands,Leiden Institute for Brain and Cognition (LIBC), Leiden University, Leiden, Netherlands
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Becker JM, Holle H, van Ryckeghem DML, Van Damme S, Crombez G, Veldhuijzen DS, Evers AWM, Rippe RCA, van Laarhoven AIM. No preconscious attentional bias towards itch in healthy individuals. PLoS One 2022; 17:e0273581. [PMID: 36054102 PMCID: PMC9439194 DOI: 10.1371/journal.pone.0273581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 08/10/2022] [Indexed: 11/24/2022] Open
Abstract
Rapidly attending towards potentially harmful stimuli to prevent possible damage to the body is a critical component of adaptive behavior. Research suggests that individuals display an attentional bias, i.e., preferential allocation of attention, for consciously perceived bodily sensations that signal potential threat, like itch or pain. Evidence is not yet clear whether an attentional bias also exists for stimuli that have been presented for such a short duration that they do not enter the stream of consciousness. This study investigated whether a preconscious attentional bias towards itch-related pictures exists in 127 healthy participants and whether this can be influenced by priming with mild itch-related stimuli compared to control stimuli. Mild itch was induced with von Frey monofilaments and scratching sounds, while control stimuli where of matched modalities but neutral. Attentional bias was measured with a subliminal pictorial dot-probe task. Moreover, we investigated how attentional inhibition of irrelevant information and the ability to switch between different tasks, i.e., cognitive flexibility, contribute to the emergence of an attentional bias. Attentional inhibition was measured with a Flanker paradigm and cognitive flexibility was measured with a cued-switching paradigm. Contrary to our expectations, results showed that participants attention was not biased towards the itch-related pictures, in facts, attention was significantly drawn towards the neutral pictures. In addition, no effect of the itch-related priming was observed. Finally, this effect was not influenced by participants’ attentional inhibition and cognitive flexibility. Therefore, we have no evidence for a preconscious attentional bias towards itch stimuli. The role of preconscious attentional bias in patients with chronic itch should be investigated in future studies.
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Affiliation(s)
- Jennifer M. Becker
- Health, Medical and Neuropsychology Unit, Institute of Psychology, Faculty of Social and Behavioral Sciences, Leiden University, Leiden, The Netherlands
- * E-mail:
| | - Henning Holle
- Department of Psychology, Faculty of Health Sciences, University of Hull, Hull, United Kingdom
| | - Dimitri M. L. van Ryckeghem
- Department of Experimental- Clinical and Health Psychology, Faculty of Psychology and Educational Sciences, Ghent University, Ghent, Belgium
- Section Experimental Health Psychology, Department of Clinical Psychological Science, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Research Unit INSIDE, Institute of Health and Behavior, Faculty of Humanities and Social Sciences, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Stefaan Van Damme
- Department of Experimental- Clinical and Health Psychology, Faculty of Psychology and Educational Sciences, Ghent University, Ghent, Belgium
| | - Geert Crombez
- Department of Experimental- Clinical and Health Psychology, Faculty of Psychology and Educational Sciences, Ghent University, Ghent, Belgium
| | - Dieuwke S. Veldhuijzen
- Health, Medical and Neuropsychology Unit, Institute of Psychology, Faculty of Social and Behavioral Sciences, Leiden University, Leiden, The Netherlands
| | - Andrea W. M. Evers
- Health, Medical and Neuropsychology Unit, Institute of Psychology, Faculty of Social and Behavioral Sciences, Leiden University, Leiden, The Netherlands
- Medical Delta professor Heatlhy Society, Leiden University, TU Delft, Erasmus Rotterdam, The Netherlands
| | - Ralph C. A. Rippe
- Research Methods and Statistics, Institute of Education and Child Studies, Faculty of Social and Behavioral Sciences, Leiden University, Leiden, The Netherlands
| | - Antoinette I. M. van Laarhoven
- Health, Medical and Neuropsychology Unit, Institute of Psychology, Faculty of Social and Behavioral Sciences, Leiden University, Leiden, The Netherlands
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Kaneko T, Kuwaki T, Kashiwadani H. Hypothalamic orexinergic neurons modulate pain and itch in an opposite way: pain relief and itch exacerbation. J Physiol Sci 2022; 72:21. [PMID: 35996084 DOI: 10.1186/s12576-022-00846-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 08/07/2022] [Indexed: 11/10/2022]
Abstract
Pain and itch are recognized as antagonistic sensations; pain suppresses itch and inhibition of pain generates itch. There is still a lack of evidence about the neural mechanism of the interaction between pain and itch in the central nervous system. In this study, we focused on the orexin (ORX) neurons in the lateral hypothalamus (LH), which mediate various "defense responses" when animals confront stressors. We found that the scratching behaviors induced by the pruritogen were significantly suppressed in ORX-neuron-ablated (ORX-abl) mice. The exaggerated pain behavior and attenuated itch behavior observed in ORX-abl mice indicated that ORX neurons modulate pain and itch in an opposite way, i.e., pain relief and itch exacerbation. In addition, most of the ORX neurons responded to both pain and itch input. Our results suggest that ORX neurons inversely regulate pain- and itch-related behaviors, which could be understood as a defense response to cope with stress environment.
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Affiliation(s)
- Tatsuroh Kaneko
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, 890-8544, Japan
| | - Tomoyuki Kuwaki
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, 890-8544, Japan
| | - Hideki Kashiwadani
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, 890-8544, Japan.
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Agarwal P, Lunge SB, Shetty NS, Karagaiah P, Daveluy S, Ortega-Loayza AG, Tzellos T, Szepietowski JC, Zouboulis CC, Grabbe S, Goldust M. Itch in Hidradenitis Suppurativa/Acne Inversa: A Systematic Review. J Clin Med 2022; 11:jcm11133813. [PMID: 35807098 PMCID: PMC9267685 DOI: 10.3390/jcm11133813] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 06/23/2022] [Accepted: 06/24/2022] [Indexed: 12/10/2022] Open
Abstract
Hidradenitis suppurativa/acne inversa (HS) is a chronic inflammatory disease of the pilosebaceous unit leading to formation of painful, inflammatory nodules, abscesses and tunnels in apocrine gland-bearing areas of the skin. Pain and drainage are the most important symptoms associated with reduction of quality of life in HS. On the other hand, an overlooked symptom in quality of life studies is itch, despite the fact that several studies have reported its importance. Various theories have tried to explain the pathogenesis of itch in HS, such as the presence of mast cells in the cell infiltrates and elevated Ig E levels in the lesional skin. Smoking and advanced stage of disease have been found to be associated with increased intensity of itch. A PUBMED search was conducted to perform a systematic literature review using the term “hidradenitis suppurativa” [all fields], the keywords “pruritus”, “itching”, “itch” [all fields] and with “AND” as operator. Mast cells and mTor signaling were found to be raised in both lesional and perilesional skin. Itch as a presenting symptom has been found in 35–82.6% of patients across multiple studies. It often co-presents with pain and may be misinterpreted as burning, stinging, tickling, tweaking, prickling, etc. The presence of itch is associated with reduced quality of life, depression and impairment of social life. Brodalumab, a monoclonal antibody against IL-17A receptor, produced significant improvements in itch, pain, QoL and depression in patients with moderate to severe HS. Statins have shown some reduction in itch intensity score. Further studies are required to gain a better understanding of the etiopathogenesis and optimal therapeutic modalities for itch in HS that will allow clinicians to better address issue and reduce its impact on quality of life.
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Affiliation(s)
- Puneet Agarwal
- Department of Dermatology, SMS Medical College and Hospital, Jaipur 302004, Rajasthan, India;
| | - Snehal Balvant Lunge
- Department of Dermatology, Venereology and Leprosy, Bharati Vidyapeeth (DTU) Medical College and Hospital, Pune 411043, Maharashtra, India; (S.B.L.); (N.S.S.)
| | - Nandini Sundar Shetty
- Department of Dermatology, Venereology and Leprosy, Bharati Vidyapeeth (DTU) Medical College and Hospital, Pune 411043, Maharashtra, India; (S.B.L.); (N.S.S.)
| | - Priyanka Karagaiah
- Department of Dermatology, Bangalore Medical College and Research Institute, Bangalore 560002, Karnataka, India;
| | - Steven Daveluy
- Department of Dermatology, Wayne State University, Detroit, MI 48202, USA;
| | - Alex G. Ortega-Loayza
- Department of Dermatology, Oregon Health and Science University, Portland, OR 97239, USA;
| | - Thrasyvoulos Tzellos
- Department of Dermatology, NLSH University Hospital, 8092 Bodø, Norway;
- European Hidradenitis Suppurativa Foundation e.V., 06847 Dessau, Germany;
| | - Jacek C. Szepietowski
- European Hidradenitis Suppurativa Foundation e.V., 06847 Dessau, Germany;
- Department of Dermatology, Venereology and Allergology, Wroclaw Medical University, 50-367 Wroclaw, Poland
- Correspondence: (J.C.S.); (M.G.)
| | - Christos C. Zouboulis
- European Hidradenitis Suppurativa Foundation e.V., 06847 Dessau, Germany;
- Departments of Dermatology, Venereology, Allergology and Immunology, Dessau Medical Center, Brandenburg Medical School Theodor Fontane and Faculty of Health Sciences Brandenburg, 06847 Dessau, Germany
| | - Stephan Grabbe
- Department of Dermatology, University Medical Center Mainz, 55131 Mainz, Germany;
| | - Mohamad Goldust
- Department of Dermatology, University Medical Center Mainz, 55131 Mainz, Germany;
- Correspondence: (J.C.S.); (M.G.)
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10
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Mechanisms and therapeutic targets for neuropathic itch. Curr Opin Neurobiol 2022; 75:102573. [PMID: 35689909 DOI: 10.1016/j.conb.2022.102573] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 04/05/2022] [Accepted: 05/06/2022] [Indexed: 01/04/2023]
Abstract
Neuropathic pruritus conditions arise from structural and/or functional damage of the peripheral or central nervous system. Novel findings of pruritus specific mediators and pathways strengthen the specificity theory of pruritus transmission, however electrophysiological studies suggest that focal activation of nociceptors and distinct discharge patterns of primary afferents also contribute to the development of the sensation of pruritus. A complex interplay between excitatory and inhibitory interneurons at spinal level, non-neuronal cells and descending modulation from upper centers contributes to neuronal sensitization and clinically to the chronicity of pruritus, as well as accompanying phenomena such as alloknesis and hyperknesis. Several topical, systemic and non-pharmacological therapeutic approaches directed at distinct targets are currently available.
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11
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Atilgan H, Doody M, Oliver DK, McGrath TM, Shelton AM, Echeverria-Altuna I, Tracey I, Vyazovskiy VV, Manohar SG, Packer AM. Human lesions and animal studies link the claustrum to perception, salience, sleep and pain. Brain 2022; 145:1610-1623. [PMID: 35348621 PMCID: PMC9166552 DOI: 10.1093/brain/awac114] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 02/24/2022] [Accepted: 02/26/2022] [Indexed: 11/24/2022] Open
Abstract
The claustrum is the most densely interconnected region in the human brain. Despite the accumulating data from clinical and experimental studies, the functional role of the claustrum remains unknown. Here, we systematically review claustrum lesion studies and discuss their functional implications. Claustral lesions are associated with an array of signs and symptoms, including changes in cognitive, perceptual and motor abilities; electrical activity; mental state; and sleep. The wide range of symptoms observed following claustral lesions do not provide compelling evidence to support prominent current theories of claustrum function such as multisensory integration or salience computation. Conversely, the lesions studies support the hypothesis that the claustrum regulates cortical excitability. We argue that the claustrum is connected to, or part of, multiple brain networks that perform both fundamental and higher cognitive functions. As a multifunctional node in numerous networks, this may explain the manifold effects of claustrum damage on brain and behaviour.
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Affiliation(s)
- Huriye Atilgan
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3PT, UK
| | - Max Doody
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3PT, UK
| | - David K. Oliver
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3PT, UK
| | - Thomas M. McGrath
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3PT, UK
| | - Andrew M. Shelton
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3PT, UK
| | | | - Irene Tracey
- Wellcome Centre for Integrative Neuroimaging, FMRIB Centre, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital and Merton College, University of Oxford, Oxford OX3 9DU, UK
| | | | - Sanjay G. Manohar
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, UK
| | - Adam M. Packer
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3PT, UK
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12
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Schön MP. The tick and I: Parasite-host interactions between ticks and humans. J Dtsch Dermatol Ges 2022; 20:818-853. [PMID: 35674196 DOI: 10.1111/ddg.14821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 04/25/2022] [Indexed: 11/28/2022]
Abstract
Ticks, particularly hard ticks (Ixodidae), which are among the most important vectors of dangerous infectious agents, feed on their hosts for extended periods of time. With this lifestyle, numerous adaptations have evolved in ticks and their hosts, the pharmacological importance of which is increasingly being recognized. Many bioactive substances in tick saliva are being considered as the basis of new drugs. For example, components of tick cement can be developed into tissue adhesives or wound closures. Analgesic and antipruritic salivary components inhibit histamine or bradykinin, while other tick-derived molecules bind opioid or cannabinoid receptors. Tick saliva inhibits the extrinsic, intrinsic, or common pathway of blood coagulation with implications for the treatment of thromboembolic diseases. It contains vasodilating substances and affects wound healing. The broad spectrum of immunomodulatory and immunosuppressive effects of tick saliva, such as inhibition of chemokines or cellular immune responses, allows development of drugs against inflammation in autoimmune diseases and/or infections. Finally, modern vaccines against ticks can curb the spread of serious infections. The medical importance of the complex tick-host interactions is increasingly being recognized and translated into first clinical applications. Using selected examples, an overview of the mutual adaptations of ticks and hosts is given here, focusing on their significance to medical advance.
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Affiliation(s)
- Michael P Schön
- Department of Dermatology, Venereology and Allergology, University Medical Center Göttingen, Germany
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13
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Schön MP. Die Zecke und ich: Parasiten-Wirt-Interaktionen zwischen Zecken und Menschen. J Dtsch Dermatol Ges 2022; 20:818-855. [PMID: 35711058 DOI: 10.1111/ddg.14821_g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 04/22/2022] [Accepted: 04/25/2022] [Indexed: 12/01/2022]
Affiliation(s)
- Michael P Schön
- Klinik für Dermatologie, Venerologie und Allergologie, Universitätsmedizin Göttingen
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14
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Objective neuromodulation basis for intrafascicular artificial somatosensation through carbon nanotube yarn electrodes. J Neurosci Methods 2022; 369:109481. [PMID: 35032498 DOI: 10.1016/j.jneumeth.2022.109481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 12/13/2021] [Accepted: 01/10/2022] [Indexed: 11/20/2022]
Abstract
BACKGROUND Intrafascicular electrical stimulation has been extensively adopted to achieve sensory feedback for limb amputees. Axon-like carbon nanotube yarn (CNTy) electrodes with both promising flexibility and spatial selectivity index (SSI) can be fascinating alternatives to generate artificial somatosensation. NEW METHOD Here we systematically disclose objective neuromodulation basis for artificial somatosensation through intrafascicular CNTy electrodes. CNTy electrodes with different exposed lengths were utilized for electrically stimulating tibial nerves in twelve rats. Somatosensory evoked potentials (SEPs) were recorded synchronously using an epidural thirty-channel electrode array. Spatiotemporal characteristics of SEPs were analyzed as current pulse amplitude (PA), pulse width (PW) and pulse frequency (PF) varied. RESULTS The current thresholds at 1Hz exhibit the lowest means when compared with those at 4 and 8Hz for most CNTy electrodes (20/28). For all the electrodes, amplitudes of SEPs and activated areas of perceptive fields increase with PWs and PAs rising, and decrease remarkably with PFs from 1 to 8Hz. Latencies of P1 and N1 of SEP peaks gradually reduced with PWs and PAs advancing. Considering high SSIs, relatively stable current thresholds, wider variation ranges of sensory magnitudes and optimal stability of perceptive fields, the L-200 μm electrodes are preferable for neuromodulation with PFs of 1 - 8Hz, PWs of 100 - 800 μs and PAs of 2 - 64 μA. COMPARISON WITH EXISTING METHODS New-type CNTy electrodes possess both promising flexibility and SSI when compared with other neural interfaces. We systematically explore objective neuromodulation basis for artificial somatosensation through CNTy electrodes for the first time. CONCLUSIONS Significantly higher SSIs, lower current and charge thresholds exist for CNTy electrodes in comparison with other peripheral-nerve interfaces. This study can, for the first time, lay a solid neuromodulation foundation for CNTy electrodes to achieve fine sensory feedback.
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15
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Common and discrete mechanisms underlying chronic pain and itch: peripheral and central sensitization. Pflugers Arch 2021; 473:1603-1615. [PMID: 34245379 DOI: 10.1007/s00424-021-02599-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 05/26/2021] [Accepted: 06/22/2021] [Indexed: 12/30/2022]
Abstract
Normally, an obvious antagonism exists between pain and itch. In normal conditions, painful stimuli suppress itch sensation, whereas pain killers often generate itch. Although pain and itch are mediated by separate pathways under normal conditions, most chemicals are not highly specific to one sensation in chronic pathologic conditions. Notably, in patients with neuropathic pain, histamine primarily induces pain rather than itch, while in patients with atopic dermatitis, bradykinin triggers itch rather than pain. Accordingly, repetitive scratching even enhances itch sensation in chronic itch conditions. Physicians often prescribe pain relievers to patients with chronic itch, suggesting common mechanisms underlying chronic pain and itch, especially peripheral and central sensitization. Rather than separating itch and pain, studies should investigate chronic itch and pain including neuropathic and inflammatory conditions. Here, we reviewed chronic sensitization leading to chronic pain and itch at both peripheral and central levels. Studies investigating the connection between pain and itch facilitate the development of new therapeutics against both chronic dysesthesias based on the underlying pathophysiology.
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16
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Wang S, Song P, Ma R, Wang Y, Yu B, Wang M, Wang M, Shen J, Dai Y, Wang Y, Xie W. Research on Characteristic of Chronic Spontaneous Urticaria Based on Multiscale Entropy. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2021; 2021:6691356. [PMID: 34122619 PMCID: PMC8172304 DOI: 10.1155/2021/6691356] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 03/21/2021] [Accepted: 04/12/2021] [Indexed: 12/12/2022]
Abstract
Chronic spontaneous urticaria (CSU) is a common skin disease which symptom is local pruritus and pain. In medicine, researchers take a certain point that the brain is the control center of CSU, but in previous experiments, the researchers found that cerebellum also had a certain effect on CSU. In order to find out the influence of CSU in the brain and cerebellum, we collected the brain resting-state fMRI data from 40 healthy controls and 32 CSU patients and used DPABI to preprocess. We calculated the entropy values of five scales by using multiscale entropy (MSE) and the average entropy values of two groups' BOLD signals; 15 regions with significant differences were found which not only had a more detailed impact in the brain but also had an impact in the cerebellum, such as precentral gyrus, lenticular putamen, and vermis of cerebellum. In addition, we found that compared with the healthy controls, the entropy values of CSU patients showed two trends which need further study. The advantage of our experiment is that the multiscale entropy value is used to get more influence regions of CSU in the brain and cerebellum. The results of this paper may provide some help for the pathological study of CSU.
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Affiliation(s)
- Shujuan Wang
- College of Mathematical Sciences, Harbin Engineering University, Harbin 150001, China
| | - Ping Song
- Department of Dermatology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Rong Ma
- College of Mathematical Sciences, Harbin Engineering University, Harbin 150001, China
| | - Yanzhong Wang
- School of Population Health & Environmental Sciences, Faculty of Life Science and Medicine, King's College London, London, UK
- Suzhou Fanhan Information Technology Co., Ltd, China
| | - Bin Yu
- Department of Dermatology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Min Wang
- College of Mathematical Sciences, Harbin Engineering University, Harbin 150001, China
| | - Meiqi Wang
- College of Mathematical Sciences, Harbin Engineering University, Harbin 150001, China
| | - Jihong Shen
- College of Mathematical Sciences, Harbin Engineering University, Harbin 150001, China
| | - Yuntao Dai
- College of Mathematical Sciences, Harbin Engineering University, Harbin 150001, China
| | - Yuming Wang
- Department of Dermatology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Wanqing Xie
- College of Mathematical Sciences, Harbin Engineering University, Harbin 150001, China
- Suzhou Fanhan Information Technology Co., Ltd, China
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17
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Klein A, Solinski HJ, Malewicz NM, Ieong HFH, Sypek EI, Shimada SG, Hartke TV, Wooten M, Wu G, Dong X, Hoon MA, LaMotte RH, Ringkamp M. Pruriception and neuronal coding in nociceptor subtypes in human and nonhuman primates. eLife 2021; 10:64506. [PMID: 33891544 PMCID: PMC8064749 DOI: 10.7554/elife.64506] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 04/12/2021] [Indexed: 12/11/2022] Open
Abstract
In humans, intradermal administration of β-alanine (ALA) and bovine adrenal medulla peptide 8–22 (BAM8-22) evokes the sensation of itch. Currently, it is unknown which human dorsal root ganglion (DRG) neurons express the receptors of these pruritogens, MRGPRD and MRGPRX1, respectively, and which cutaneous afferents these pruritogens activate in primate. In situ hybridization studies revealed that MRGPRD and MRGPRX1 are co-expressed in a subpopulation of TRPV1+ human DRG neurons. In electrophysiological recordings in nonhuman primates (Macaca nemestrina), subtypes of polymodal C-fiber nociceptors are preferentially activated by ALA and BAM8-22, with significant overlap. When pruritogens ALA, BAM8-22, and histamine, which activate different subclasses of C-fiber afferents, are administered in combination, human volunteers report itch and nociceptive sensations similar to those induced by a single pruritogen. Our results provide evidence for differences in pruriceptive processing between primates and rodents, and do not support the spatial contrast theory of coding of itch and pain.
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Affiliation(s)
- Amanda Klein
- Department of Neurosurgery, Neurosurgery Pain Research Institute, School of Medicine, Johns Hopkins University, Baltimore, United States.,Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, United States
| | - Hans Jürgen Solinski
- Molecular Genetics Section, National Institute of Dental and Craniofacial Research, Bethesda, United States.,Department of Experimental Pain Research, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Nathalie M Malewicz
- Department of Anesthesiology, School of Medicine, Yale University, New Haven, United States.,Department of Anesthesiology, Intensive Care Medicine and Pain Management, Medical Faculty of Ruhr-University Bochum, BG University Hospital Bergmannsheil, Bochum, Germany
| | - Hada Fong-Ha Ieong
- Department of Anesthesiology, School of Medicine, Yale University, New Haven, United States
| | - Elizabeth I Sypek
- The Solomon H. Snyder Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, United States
| | - Steven G Shimada
- Department of Anesthesiology, School of Medicine, Yale University, New Haven, United States
| | - Timothy V Hartke
- Department of Neurosurgery, Neurosurgery Pain Research Institute, School of Medicine, Johns Hopkins University, Baltimore, United States
| | - Matthew Wooten
- Department of Neurosurgery, Neurosurgery Pain Research Institute, School of Medicine, Johns Hopkins University, Baltimore, United States
| | - Gang Wu
- Department of Neurosurgery, Neurosurgery Pain Research Institute, School of Medicine, Johns Hopkins University, Baltimore, United States
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, United States.,Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Mark A Hoon
- Molecular Genetics Section, National Institute of Dental and Craniofacial Research, Bethesda, United States
| | - Robert H LaMotte
- Department of Anesthesiology, School of Medicine, Yale University, New Haven, United States
| | - Matthias Ringkamp
- Department of Neurosurgery, Neurosurgery Pain Research Institute, School of Medicine, Johns Hopkins University, Baltimore, United States
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18
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Abstract
Inhibitory interneurons in the adult spinal dorsal horn (DH) can be neurochemically classified into subpopulations that regulate distinct somatosensory modalities. Although inhibitory networks in the rodent DH undergo dramatic remodeling over the first weeks of life, little is known about the maturation of identified classes of GABAergic interneurons, or whether their role in somatosensation shifts during development. We investigated age-dependent changes in the connectivity and function of prodynorphin (DYN)-lineage neurons in the mouse DH that suppress mechanosensation and itch during adulthood. In vitro patch clamp recordings revealed a developmental increase in primary afferent drive to DYN interneurons and a transition from exclusive C-fiber monosynaptic input to mixed A-fiber and C-fiber innervation. Although most adult DYN interneurons exhibited tonic firing as expected from their inhibitory phenotype, neonatal and adolescent DYN cells were predominantly classified as phasic or single-spiking. Importantly, we also found that most of the inhibitory presynaptic terminals contacting lamina I spinoparabrachial projection neurons (PNs) originate from DYN neurons. Furthermore, inhibitory synaptic input from DYN interneurons onto PNs was weaker during the neonatal period, likely reflecting a lower number of GABAergic terminals and a reduced probability of GABA release compared to adults. Finally, spinal DYN interneurons attenuated mechanical sensitivity throughout development, but this population dampened acute nonhistaminergic itch only during adulthood. Collectively, these findings suggest that the spinal "gates" controlling sensory transmission to the brain may emerge in a modality-selective manner during early life due to the postnatal tuning of inhibitory synaptic circuits within the DH.
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19
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Abstract
Mechanistic theories of itch are based on neuronal specificity, stimulus intensity, and temporal or spatial discharge patterns. Traditionally, these theories are conceptualized as mutually exclusive, assuming that finding evidence for one theory would exclude the others and could sufficiently explain itch. Current experimental data primarily support the specificity or pattern theory of itch. However, in contrast to an assumed inherent exclusivity, recent results have shown that even within itch-specific pathways in the spinal cord, temporal discharge patterns are important as sustained pruriceptor is required to allow successful transsynaptic signal progression. Also, optogenetic activation of pruriceptors suggest that the combination of neuronal specificity and temporal pattern determines the sensory effect: tonic activation of pruriceptors is required to induce scratching behavior whereas short-lasting stimulation rather causes withdrawal. In addition to the mere duration of discharge, also the temporal pattern or spatial aspects could critically contribute to elicit pruritus instead of pain. Basic neurophysiological studies trying to validate neuronal theories for pruritus in their pure form provide unitary concepts leading from neuronal discharge to the itch sensation. However, the crucial clinical questions have the opposite perspective: which mechanisms explain the chronic itch in a given patient or a given disease? In trying to solve these clinical problems we should not feel bound to the mutual exclusive nature of itch theories, but rather appreciate blending several theories and also accept combinations of itch and pain. Thus, blended versions of itch theories might better suffice for an explanation of chronic itch in patients and will improve the basis for mechanistic treatment options.
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Affiliation(s)
- Martin Schmelz
- Department of Experimental Pain Research, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
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20
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Solinski HJ, Rukwied R. Electrically Evoked Itch in Human Subjects. Front Med (Lausanne) 2021; 7:627617. [PMID: 33553220 PMCID: PMC7855585 DOI: 10.3389/fmed.2020.627617] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 12/23/2020] [Indexed: 11/13/2022] Open
Abstract
Administration of chemicals (pruritogens) into the skin evokes itch based on signal transduction mechanisms that generate action potentials mainly in mechanically sensitive and insensitive primary afferent C-fibers (pruriceptors). These signals from peripheral neurons are processed in spinal and supra-spinal centers of the central nervous system and finally generate the sensation of itch. Compared to chemical stimulation, electrical activation of pruriceptors would allow for better temporal control and thereby a more direct functional assessment of their activation. Here, we review the electrical stimulation paradigms which were used to evoke itch in humans in the past. We further evaluate recent attempts to explore electrically induced itch in atopic dermatitis patients. Possible mechanisms underlying successful pruritus generation in chronic itch patients by transdermal slowly depolarizing electrical stimulation are discussed.
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Affiliation(s)
- Hans Jürgen Solinski
- Department of Experimental Pain Research, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Roman Rukwied
- Department of Experimental Pain Research, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
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21
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Kahremany S, Hofmann L, Harari M, Gruzman A, Cohen G. Pruritus in psoriasis and atopic dermatitis: current treatments and new perspectives. Pharmacol Rep 2021; 73:443-453. [PMID: 33460006 DOI: 10.1007/s43440-020-00206-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 11/11/2020] [Accepted: 11/29/2020] [Indexed: 02/06/2023]
Abstract
Psoriasis and atopic dermatitis (AD) are two common chronic inflammatory skin diseases. Although showing different etiology and clinical manifestations, patients with either disease suffer from low health-related quality of life due to pruritus (dermal itch). Recent studies have revealed that more than 85% of psoriasis patients suffer from pruritus, and it is also the dominating symptom of AD. However, as this is a non-life treating symptom, it was partly neglected for years. In this review, we focus on current findings as well as the impact and potential treatments of pruritus in these two skin diseases. We first distinguish the type of itch based on involved mediators and modulators. This clear delineation between the types of pruritus based on involved receptors and pathways allows for precise treatment. In addition, insights into recent clinical trials aimed to alleviate pruritus by targeting these receptors are presented. We also report about novel advances in combinatorial treatments, dedicated to the type of pruritus linked to a causal disease. Altogether, we suggest that only a focused treatment tailored to the primary disease and the underlying molecular signals will provide fast and sustained relief of pruritus associated with psoriasis or AD.
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Affiliation(s)
- Shirin Kahremany
- Department of Chemistry, Faculty of Exact Sciences, Bar-Ilan University, 5290002, Ramat Gan, Israel. .,The Skin Research Institute, The Dead Sea and Arava Science Center, 86910, Masada, Israel.
| | - Lukas Hofmann
- Department of Chemistry, Faculty of Exact Sciences, Bar-Ilan University, 5290002, Ramat Gan, Israel
| | - Marco Harari
- Medical Climatotherapy Unit, The Dead Sea and Arava Science Center, 86910, Masada, Israel
| | - Arie Gruzman
- Department of Chemistry, Faculty of Exact Sciences, Bar-Ilan University, 5290002, Ramat Gan, Israel
| | - Guy Cohen
- The Skin Research Institute, The Dead Sea and Arava Science Center, 86910, Masada, Israel.,Ben Gurion University of the Negev, Eilat Campus, 8855630, Eilat, Israel
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22
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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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23
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Kahremany S, Hofmann L, Gruzman A, Cohen G. Advances in Understanding the Initial Steps of Pruritoceptive Itch: How the Itch Hits the Switch. Int J Mol Sci 2020; 21:ijms21144883. [PMID: 32664385 PMCID: PMC7402353 DOI: 10.3390/ijms21144883] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 07/07/2020] [Accepted: 07/08/2020] [Indexed: 02/07/2023] Open
Abstract
Pruritoceptive (dermal) itch was long considered an accompanying symptom of diseases, a side effect of drug applications, or a temporary sensation induced by invading pruritogens, as produced by the stinging nettle. Due to extensive research in recent years, it was possible to provide detailed insights into the mechanism of itch mediation and modulation. Hence, it became apparent that pruritus is a complex symptom or disease in itself, which requires particular attention to improve patients’ health. Here, we summarize recent findings in pruritoceptive itch, including how this sensation is triggered and modulated by diverse endogenous and exogenous pruritogens and their receptors. A differentiation between mediating pruritogen and modulating pruritogen seems to be of great advantage to understand and decipher the molecular mechanism of itch perception. Only a comprehensive view on itch sensation will provide a solid basis for targeting this long-neglected adverse sensation accompanying numerous diseases and many drug side effects. Finally, we identify critical aspects of itch perception that require future investigation.
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Affiliation(s)
- Shirin Kahremany
- Department of Chemistry, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel; (L.H.); (A.G.)
- The Skin Research Institute, The Dead Sea and Arava Science Center, Masada 86910, Israel;
- Correspondence:
| | - Lukas Hofmann
- Department of Chemistry, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel; (L.H.); (A.G.)
| | - Arie Gruzman
- Department of Chemistry, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel; (L.H.); (A.G.)
| | - Guy Cohen
- The Skin Research Institute, The Dead Sea and Arava Science Center, Masada 86910, Israel;
- Ben-Gurion University of the Negev, Eilat Campus, Eilat 8855630, Israel
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24
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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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25
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Ganchingco JRC, Fukuyama T, Yoder JA, Bäumer W. Calcium imaging of primary canine sensory neurons: Small-diameter neurons responsive to pruritogens and algogens. Brain Behav 2019; 9:e01428. [PMID: 31571393 PMCID: PMC6908857 DOI: 10.1002/brb3.1428] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 08/28/2019] [Accepted: 08/31/2019] [Indexed: 01/19/2023] Open
Abstract
INTRODUCTION Rodent primary sensory neurons are commonly used for studying itch and pain neurophysiology, but translation from rodents to larger mammals and humans is not direct and requires further validation to make correlations. METHODS This study developed a primary canine sensory neuron culture from dorsal root ganglia (DRG) excised from cadaver dogs. Additionally, the canine DRG cell cultures developed were used for single-cell ratiometric calcium imaging, with the activation of neurons to the following pruritogenic and algogenic substances: histamine, chloroquine, canine protease-activated receptor 2 (PAR2) activating peptide (SLIGKT), compound 48/80, 5-hydroxytryptamine receptor agonist (5-HT), bovine adrenal medulla peptide (BAM8-22), substance P, allyl isothiocyanate (AITC), and capsaicin. RESULTS This study demonstrates a simple dissection and rapid processing of DRG collected from canine cadavers used to create viable primary sensory neuron cultures to measure responses to pruritogens and algogens. CONCLUSION Ratiometric calcium imaging demonstrated that small-diameter canine sensory neurons can be activated by multiple stimuli, and a single neuron can react to both a pruritogenic stimulation and an algogenic stimulation.
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Affiliation(s)
- Joy Rachel C Ganchingco
- Department of Molecular Biomedical Sciences, North Carolina State University College of Veterinary Medicine, Raleigh, NC, USA
| | - Tomoki Fukuyama
- Department of Molecular Biomedical Sciences, North Carolina State University College of Veterinary Medicine, Raleigh, NC, USA.,Laboratory of Veterinary Pharmacology, Azabu University, Kanagawa, Japan
| | - Jeffrey A Yoder
- Department of Molecular Biomedical Sciences, North Carolina State University College of Veterinary Medicine, Raleigh, NC, USA
| | - Wolfgang Bäumer
- Department of Molecular Biomedical Sciences, North Carolina State University College of Veterinary Medicine, Raleigh, NC, USA.,Institute of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
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26
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Abstract
Chronic pruritus may arise from different conditions, including dermatological, systemic, neurologic, psychiatric, and psychosomatic diseases, leading to a substantial decrease in the quality of life of affected patients. The neurobiological mechanisms involved in chronic pruritus are not yet fully understood. However, in recent years important achievements have been made in this regard. This article aims to provide an overview of the current understanding of these mechanisms. The complex network of neurons, keratinocytes, inflammatory cells, cytokines, and neurotrophic factors which play a role in the development and maintenance of chronic pruritus are highlighted, as well as the pruritogens involved in pruritic diseases in humans. Additionally, the importance of neuropathy and scratch-induced changes for the pathophysiology of chronic pruritus are discussed. The new findings on the neurobiological mechanisms underlying chronic pruritus have already led to the development of novel therapies, e. g., monoclonal antibodies against specific interleukins, which are important for pruritus transmission. A deeper understanding of the neurobiological mechanisms is necessary in order to develop specifically targeted therapeutic options and thus provide better care for affected patients.
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Affiliation(s)
- M P Pereira
- Kompetenzzentrum Chronischer Pruritus (KCP), Klinik für Hautkrankheiten, Universitätsklinikum Münster, Von-Esmarch-Str. 58, 48149, Münster, Deutschland.
| | - K Agelopoulos
- Kompetenzzentrum Chronischer Pruritus (KCP), Klinik für Hautkrankheiten, Universitätsklinikum Münster, Von-Esmarch-Str. 58, 48149, Münster, Deutschland
| | - A E Kremer
- Medizinische Klinik 1, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Deutschland
| | - M Schmelz
- Klinik für Anästhesiologie und Operative Intensivmedizin, Fakultät für Klinische Medizin Mannheim, Ruprecht-Karls-Universität Heidelberg, Mannheim, Deutschland
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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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28
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Katayama C, Hayashida Y, Sugiyama S, Shiohara T, Aoyama Y. Prurigo nodularis as a sweat gland/duct-related disorder: resolution associated with restoration of sweating disturbance. Arch Dermatol Res 2019; 311:555-562. [PMID: 31152230 DOI: 10.1007/s00403-019-01937-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 05/12/2019] [Accepted: 05/24/2019] [Indexed: 11/30/2022]
Abstract
Little attention has been given to the involvement of sweat glands/ducts in the pathogenesis of prurigo nodularis (PN). According to recent studies, PN is likely to develop under conditions characterized by dry skin, such as atopic dermatitis (AD), suggesting a strong impact of skin dryness on PN development. No therapeutic modalities produced complete resolution of PN without exacerbations. We previously reported that increases in skin dryness by sweating disturbance could initiate the development of AD. We investigated whether sweating responses were impaired in refractory PN lesions; and, if so, we asked whether the PN lesions could resolve by restoring sweating disturbance. Using the impression mold technique, which allows an accurate quantification of individual sweat gland/duct activity, we examined basal sweating under quiescent conditions and inducible sweating responses to thermal stimulus in PN lesions and normal-appearing skin in the same patients before and after treatment with a moisturizer or topical corticosteroids. Sweating disturbance, either basal or inducible, was most profoundly detected in the "hub" structure corresponding to the center of PN papule before the treatment. This sweating disturbance was immunohistochemically associated with the leakage of sweat into the dermis. This disturbance was restored by treatment with a moisturizer. Our limitations include a relatively small patient cohort and lack of blinding. Sweating disturbance could be one of the aggravating factors of PN development. Refractory PN with low skin hydration may resolve by restoring sweating disturbance.
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Affiliation(s)
- Chieko Katayama
- Department of Dermatology, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama, 701-0192, Japan
| | - Yuki Hayashida
- Department of Dermatology, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama, 701-0192, Japan
| | - Seiko Sugiyama
- Department of Dermatology, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama, 701-0192, Japan.,Department of Dermatology, Kawasaki General Medical Center, Kawasaki Medical School, Okayama, Okayama, Japan
| | - Tetsuo Shiohara
- Department of Dermatology, Kyorin University School of Medicine, Mitaka, Tokyo, Japan
| | - Yumi Aoyama
- Department of Dermatology, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama, 701-0192, Japan.
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29
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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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30
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Minimally invasive non-surgical locally injected vitamin C versus the conventional surgical depigmentation in treatment of gingival hyperpigmentation of the anterior esthetic zone: A prospective comparative study. CLINICAL NUTRITION EXPERIMENTAL 2019. [DOI: 10.1016/j.yclnex.2018.12.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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31
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Kim YW, Zhou T, Ko EA, Kim S, Lee D, Seo Y, Kwon N, Choi T, Lim H, Cho S, Bae G, Hwang Y, Kim D, Park H, Lee M, Jang E, Choi J, Bae H, Lim I, Bang H, Ko JH. Prediction of itching diagnostic marker through RNA sequencing of contact hypersensitivity and skin scratching stimulation mice models. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2019; 23:151-159. [PMID: 30820159 PMCID: PMC6384194 DOI: 10.4196/kjpp.2019.23.2.151] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 01/04/2019] [Accepted: 01/10/2019] [Indexed: 01/28/2023]
Abstract
Pruritus (itching) is classically defined as an unpleasant cutaneous sensation that leads to scratching behavior. Although the scientific criteria of classification for pruritic diseases are not clear, it can be divided as acute or chronic by duration of symptoms. In this study, we investigated whether skin injury caused by chemical (contact hypersensitivity, CHS) or physical (skin-scratching stimulation, SSS) stimuli causes initial pruritus and analyzed gene expression profiles systemically to determine how changes in skin gene expression in the affected area are related to itching. In both CHS and SSS, we ranked the Gene Ontology Biological Process terms that are generally associated with changes. The factors associated with upregulation were keratinization, inflammatory response and neutrophil chemotaxis. The Kyoto Encyclopedia of Genes and Genomes pathway shows the difference of immune system, cell growth and death, signaling molecules and interactions, and signal transduction pathways. Il1a , Il1b and Il22 were upregulated in the CHS, and Tnf, Tnfrsf1b, Il1b, Il1r1 and Il6 were upregulated in the SSS. Trpc1 channel genes were observed in representative itching-related candidate genes. By comparing and analyzing RNA-sequencing data obtained from the skin tissue of each animal model in these characteristic stages, it is possible to find useful diagnostic markers for the treatment of itching, to diagnose itching causes and to apply customized treatment.
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Affiliation(s)
- Young-Won Kim
- Department of Physiology, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Tong Zhou
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV 89557, USA
| | - Eun-A Ko
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV 89557, USA
| | - Seongtae Kim
- Department of Physiology, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Donghee Lee
- Department of Physiology, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Yelim Seo
- Department of Physiology, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Nahee Kwon
- Department of Medicine, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Taeyeon Choi
- Department of Medicine, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Heejung Lim
- Department of Medicine, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Sungvin Cho
- Department of Medicine, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Gwanhui Bae
- Department of Medicine, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Yuseong Hwang
- Department of Medicine, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Dojin Kim
- Department of Medicine, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Hyewon Park
- Department of Medicine, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Minjae Lee
- Department of Medicine, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Eunkyung Jang
- Department of Medicine, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Jeongyoon Choi
- Department of Physiology, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Hyemi Bae
- Department of Physiology, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Inja Lim
- Department of Physiology, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Hyoweon Bang
- Department of Physiology, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Jae-Hong Ko
- Department of Physiology, Chung-Ang University College of Medicine, Seoul 06974, Korea
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Schneider G, Stumpf A, Burgmer M, Volmering L, Broecker P, Ständer S. Relations between a standardized experimental stressor and cutaneous sensory function in patients with chronic pruritus and healthy controls: an experimental case-control study. J Eur Acad Dermatol Venereol 2018; 32:2230-2236. [PMID: 29706009 PMCID: PMC6585676 DOI: 10.1111/jdv.15030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 03/28/2018] [Indexed: 11/28/2022]
Abstract
Background While chronic pruritus (CP) is a frequent symptom, many aspects of its underlying pathophysiological mechanisms still need elucidation. Research on sensory cutaneous function and on the influence of stress has been conducted mainly in patients with atopic dermatitis but is lacking for patients with CP. Objective To assess whether a standardized social stressor influences cutaneous sensory function in patients with CP in comparison with healthy controls (HC). Methods Case–control study; 33 CP and 30 HC were submitted to the standardized quantitative sensory testing protocol before and after the Trier Social Stress Test and 1 h later. Intraepidermal nerve fibre density (IENFD) was determined. Results Mechanical pain sensitivity and mechanical detection thresholds were significantly higher in CP than in HC, and mechanical detection thresholds increased more in CP than in HC over the three measurements. In both groups, cold pain threshold increased and heat pain threshold decreased from before to after the stress test and remained constant 1 h later. Only in CP, almost all QST tests induced at least a small amount of pruritus, which was not significantly altered by the stress test. IENFD in pruritic skin was significantly reduced in CP when compared to healthy controls. Conclusion Peripheral thermal sensory function was not altered in CP despite reduced IENFD in lesional skin, but we could demonstrate central sensitization processes specifically in CP and influences of an acute stressor inducing more sensitivity to thermal pain in both groups.
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Affiliation(s)
- G Schneider
- Department of Psychosomatics and Psychotherapy, University Hospital Münster, Münster, Germany.,Center for Chronic Pruritus, University Hospital Münster, Münster, Germany
| | - A Stumpf
- Department of Psychosomatics and Psychotherapy, University Hospital Münster, Münster, Germany
| | - M Burgmer
- Department of Psychosomatics and Psychotherapy, University Hospital Münster, Münster, Germany
| | - L Volmering
- Department of Psychosomatics and Psychotherapy, University Hospital Münster, Münster, Germany
| | - P Broecker
- Department of Dermatology, University Hospital Münster, Münster, Germany
| | - S Ständer
- Center for Chronic Pruritus, University Hospital Münster, Münster, Germany.,Department of Dermatology, University Hospital Münster, Münster, Germany
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Abstract
Atopic dermatitis (AD) is the most common itchy dermatosis that affects millions of children and adults worldwide. Chronic itch in this condition has significant impact on measures of quality of life, such as sleep. Treating itch in AD has been challenging for decades, but new drugs have emerged in the last year with significant anti-pruritic effect. The optimal treatment regimen for atopic itch addresses barrier dysfunction, inflammation, neural hypersensitivity, and the itch-scratch cycle. Topical moisturizers remain the foundation of treatment and should be used by all patients with AD-associated pruritus. Step-wise therapy, from topical anti-inflammatory creams to systemic monoclonal antibodies and immunosuppressants, is recommended. There are multiple adjuvant therapies that can be used, especially to target itch in the setting of minimal skin inflammation. Finally, patient education, sleep management, and stress relief are important components to optimize outcomes. This review assesses the latest advances and treatment recommendations for pruritus in AD. Finally, suggested therapeutic ladders and emerging treatments are discussed.
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Vekic DA, Cains GD. Hidradenitis suppurativa, a review of pathogenesis, associations and management. Part 2. Australas J Dermatol 2018; 59:261-266. [PMID: 29363099 DOI: 10.1111/ajd.12766] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 11/02/2017] [Indexed: 01/02/2023]
Abstract
Hidradenitis suppurativa is a chronic, painful, autoinflammatory condition resulting in nodules, abscesses and sinus tracts. We present an evidence-based review providing new understanding of the pathogenesis of hidradenitis suppurativa and associated comorbidities. By the nature of their speciality, dermatologists are uniquely positioned to investigate and treat patients.
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Affiliation(s)
- Dunja Ana Vekic
- Ingham Institute for Applied Medical Research, Sydney, NSW, Australia.,Department of Dermatology, Liverpool Hospital, Sydney, NSW, Australia.,University of New South Wales, Sydney, NSW, Australia
| | - Geoffrey David Cains
- Ingham Institute for Applied Medical Research, Sydney, NSW, Australia.,University of New South Wales, Sydney, NSW, Australia
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35
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Effects of a Nociceptin Receptor Antagonist on Experimentally Induced Scratching Behavior in Mice. NEUROPHYSIOLOGY+ 2017. [DOI: 10.1007/s11062-017-9641-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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36
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Lin SH, Steinhoff M, Ikoma A, Chang YC, Cheng YR, Chandra Kopparaju R, Ishii S, Sun WH, Chen CC. Involvement of TRPV1 and TDAG8 in Pruriception Associated with Noxious Acidosis. J Invest Dermatol 2017; 137:170-178. [DOI: 10.1016/j.jid.2016.07.037] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 06/27/2016] [Accepted: 07/18/2016] [Indexed: 02/06/2023]
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37
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Descending serotonergic and noradrenergic systems do not regulate the antipruritic effects of cannabinoids. Acta Neuropsychiatr 2016; 28:321-326. [PMID: 27805543 DOI: 10.1017/neu.2016.16] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND For centuries, cannabinoids have been known to be effective in pain states. Itch and pain are two sensations sharing a lot in common. OBJECTIVE The goal of this research was to observe whether the cannabinoid agonist WIN 55,212-2 reduces serotonin-induced scratching behaviour and whether neurotoxic destruction of descending serotonergic and noradrenergic pathways mediate the antipruritic effect of WIN 55,212-2. Material and methods Scratching behaviour was induced by intradermal injection of serotonin (50 µg/50 µl/mouse) to Balb/c mice. The neurotoxins 5,7-dihydroxytryptamine (5,7-DHT, 50 μg/mouse) and 6-hydroxydopamine (6-OHDA, 20 μg/mouse) are applied intrathecally to deplete serotonin and noradrenaline in the spinal cord. WIN 55,212-2 (1, 3, 10 mg/kg, i.p.) dose-dependently attenuated serotonin-induced scratches. Neurotoxic destruction of neither the serotonergic nor the noradrenergic systems by 5,7-DHT and 6-OHDA, respectively, had any effect on the antipruritic action of WIN 55,212-2. CONCLUSION Our findings indicate that cannabinoids dose-dependently reduce serotonin-induced scratching behaviour and neurotoxic destruction of descending inhibitory pathways does not mediate this antipruritic effect.
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Du T, Bar-Hen A, Bhatia JS, Wolpowitz D. Loss of Papillary Dermal Calcitonin Gene Related Peptide-Expressing Neurons Significantly Correlates with Uremic Pruritus. J Invest Dermatol 2016; 136:2323-2325. [PMID: 27448750 DOI: 10.1016/j.jid.2016.06.629] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 05/11/2016] [Accepted: 06/03/2016] [Indexed: 10/21/2022]
Affiliation(s)
- Tiankai Du
- Department of Dermatology, Boston University, Boston, Massachusetts, USA
| | | | | | - Deon Wolpowitz
- Department of Dermatology, Boston University, Boston, Massachusetts, USA; Department of Dermatopathology, Boston University, Boston, Massachusetts, USA.
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Inhibition of the mammalian target of rapamycin complex 1 signaling pathway reduces itch behaviour in mice. Pain 2016; 156:1519-1529. [PMID: 25906350 DOI: 10.1097/j.pain.0000000000000197] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Activated mammalian target of rapamycin (P-mTOR) has been shown to maintain the sensitivity of subsets of small-diameter primary afferent A-nociceptors. Local or systemic inhibition of the mTOR complex 1 (mTORC1) pathway reduced punctate mechanical and cold sensitivity in neuropathic pain and therefore offered a new approach to chronic pain control. In this study, we have investigated the effects of the rapamycin analog temsirolimus (CCI-779) on itch. Bouts of scratching induced by the histamine-dependent pruritogenic compound 48/80 and histamine-independent pruritogens, chloroquine and SLIGRL-NH2, injected intradermally were significantly reduced by local (intradermal) or systemic (intraperitoneal, i.p.) pretreatment with CCI-779. We also investigated the action of metformin, a drug taken to control type 2 diabetes and recently shown to inhibit mTORC1 in vivo. Although the response to nonhistaminergic stimuli was reduced at all of the time points tested, scratching to compound 48/80 was modified by metformin only when the drug was injected 24 hours before this pruritogen. We also examined the colocalization of P-mTOR with gastrin-releasing peptide, a putative marker for some itch-sensitive primary afferents, and found that P-mTOR was coexpressed in less than 5% of gastrin-releasing peptide-positive fibers in the mouse skin. Taken together, the data highlight the role that P-mTOR-positive A-fibers play in itch signaling and underline the importance of the mTORC1 pathway in the regulation of homeostatic primary afferent functions such as pain and itch. The actions of the antidiabetic drug metformin in ameliorating nonhistamine-mediated itch also suggest a new therapeutic route for the control of this category of pruritus.
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40
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Intractable pruritus in neuromyelitis optica. Neurol Sci 2016; 37:949-54. [DOI: 10.1007/s10072-016-2523-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 02/16/2016] [Indexed: 10/22/2022]
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41
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O'Leary DJ. A Swallowed Needle in a Cat Treated for Feline Hyperaesthesia Syndrome. Acupunct Med 2015; 33:336-7. [DOI: 10.1136/acupmed-2015-010807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/28/2015] [Indexed: 11/04/2022]
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42
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Gunduz O, Topuz RD, Todurga ZG, Duvan K, Karadag CH, Ulugol A. Effect of Activation of the GLT-1 Transporter by a Beta-Lactam Antibiotic on Serotonin-Induced Scratching Behavior in Mice. NEUROPHYSIOLOGY+ 2015. [DOI: 10.1007/s11062-015-9494-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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43
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Wee SY, Park JH, Jeong HG, Choi CY. A Case of Multiple Piloleiomyoma on the Shoulder, which is Mistaken for Keloid. ARCHIVES OF AESTHETIC PLASTIC SURGERY 2015. [DOI: 10.14730/aaps.2015.21.2.81] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Syeo Young Wee
- Department of Plastic and Reconstructive Surgery, Soonchunhyang Gumi Hospital, Soonchunhyang University College of Medicine, Gumi, Korea
| | - Jun Ho Park
- Department of Plastic and Reconstructive Surgery, Soonchunhyang Gumi Hospital, Soonchunhyang University College of Medicine, Gumi, Korea
| | - Hyun Gyo Jeong
- Department of Plastic and Reconstructive Surgery, Soonchunhyang Gumi Hospital, Soonchunhyang University College of Medicine, Gumi, Korea
| | - Chang Yong Choi
- Department of Plastic and Reconstructive Surgery, Soonchunhyang Gumi Hospital, Soonchunhyang University College of Medicine, Gumi, Korea
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Desbordes G, Li A, Loggia ML, Kim J, Schalock PC, Lerner E, Tran TN, Ring J, Rosen BR, Kaptchuk TJ, Pfab F, Napadow V. Evoked itch perception is associated with changes in functional brain connectivity. NEUROIMAGE-CLINICAL 2014; 7:213-21. [PMID: 25610783 PMCID: PMC4300003 DOI: 10.1016/j.nicl.2014.12.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 10/28/2014] [Accepted: 12/01/2014] [Indexed: 02/07/2023]
Abstract
Chronic itch, a highly debilitating condition, has received relatively little attention in the neuroimaging literature. Recent studies suggest that brain regions supporting itch in chronic itch patients encompass sensorimotor and salience networks, and corticostriatal circuits involved in motor preparation for scratching. However, how these different brain areas interact with one another in the context of itch is still unknown. We acquired BOLD fMRI scans in 14 atopic dermatitis patients to investigate resting-state functional connectivity before and after allergen-induced itch exacerbated the clinical itch perception in these patients. A seed-based analysis revealed decreased functional connectivity from baseline resting state to the evoked-itch state between several itch-related brain regions, particularly the insular and cingulate cortices and basal ganglia, where decreased connectivity was significantly correlated with increased levels of perceived itch. In contrast, evoked itch increased connectivity between key nodes of the frontoparietal control network (superior parietal lobule and dorsolateral prefrontal cortex), where higher increase in connectivity was correlated with a lesser increase in perceived itch, suggesting that greater interaction between nodes of this executive attention network serves to limit itch sensation via enhanced top-down regulation. Overall, our results provide the first evidence of itch-dependent changes in functional connectivity across multiple brain regions. Atopic dermatitis patients were subjected to allergen-induced itch. Evoked itch reduced functional connectivity between itch-related brain regions. Evoked itch increased functional connectivity within frontoparietal control network. The above changes in functional connectivity correlated with perceived itch level. Itch sensation may be top-down regulated by frontoparietal control network.
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Key Words
- AD, atopic dermatitis
- ASL, arterial spin labeling
- Atopic dermatitis
- BA, Brodmann area
- BOLD, blood-oxygen-level dependent
- DMN, default mode network
- ECG, electrocardiography
- Eczema
- GLM, general linear model
- ITCH, evoked itch resting-state scan
- Insula
- L, left
- MNI, Montreal Neurological Institute
- MR, magnetic resonance
- PCC, posterior cingulate cortex
- PET, positron emission tomography
- PMC, premotor cortex
- Pruritus
- Putamen
- R, right
- REST, baseline resting-state scan
- S1/M1, primary sensorimotor cortex
- SCORAD, SCORing atopic dermatitis scale
- SPL, Superior parietal lobule
- VAS, visual analog scale
- aMCC, anterior mid-cingulate cortex
- dlPFC, dorsolateral prefrontal cortex
- fMRI, functional magnetic resonance imaging
- fcMRI, functional connectivity magnetic resonance imaging
- pMCC, posterior mid-cingulate cortex
- vlPFC, ventrolateral prefrontal cortex.
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Affiliation(s)
- Gaëlle Desbordes
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Ang Li
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Marco L Loggia
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Jieun Kim
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Peter C Schalock
- Department of Dermatology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Ethan Lerner
- Department of Dermatology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Thanh N Tran
- Department of Dermatology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Johannes Ring
- Department of Dermatology and Allergy, Technische Universität München, Munich, Germany
| | - Bruce R Rosen
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Ted J Kaptchuk
- Department of Internal Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Florian Pfab
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA ; Department of Dermatology and Allergy, Technische Universität München, Munich, Germany ; Department of Prevention and Sports Medicine, Technische Universität München, Munich, Germany
| | - Vitaly Napadow
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA ; Department of Radiology, Logan College of Chiropractic, Chesterfield, MO, USA ; Department of Biomedical Engineering, Kyunghee University, Yongin, Korea
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Blockade of cannabinoid CB1 and CB2 receptors does not prevent the antipruritic effect of systemic paracetamol. Acta Neurol Belg 2014; 114:307-9. [PMID: 24399199 DOI: 10.1007/s13760-013-0272-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 12/17/2013] [Indexed: 01/16/2023]
Abstract
Cannabinoid CB1 receptors have been shown to mediate the antinociceptive, but not the hypothermic, action of the worldwide used analgesic, paracetamol. Since itch and pain sensations share many similarities, the purpose of the present study was to investigate whether blockade of cannabinoid CB1 and CB2 receptors participates in the antipruritic activity of paracetamol in mice. Scratching behavior was induced by intradermal serotonin injection into the rostral part of the back of the mice. After serotonin administration, scratching of the injected site by the hind paws were videotaped and counted for 30 min. Serotonin-induced scratching behavior was attenuated with high-dose paracetamol (300 mg/kg). The CB1 receptor antagonist, AM-251 (1 mg/kg), and the CB2 receptor antagonist, SR-144528 (1 mg/kg), did not alter the anti-scratching behavioral effect of paracetamol. Our results indicate that, in contrast to its antinociceptive action, but similar to its hypothermic effect, cannabinoid receptors are not involved in the antipruritic activity of paracetamol.
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Jung DL, Lee SD, Choi IH, Na HS, Hong SU. Effects of electroacupuncture on capsaicin-induced model of atopic dermatitis in rats. J Dermatol Sci 2014; 74:23-30. [DOI: 10.1016/j.jdermsci.2013.11.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 11/24/2013] [Accepted: 11/27/2013] [Indexed: 12/21/2022]
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Psychological stress with long-standing allergic dermatitis causes psychodermatological conditions in mice. J Invest Dermatol 2014; 134:1561-1569. [PMID: 24448032 DOI: 10.1038/jid.2014.31] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 11/28/2013] [Accepted: 12/22/2013] [Indexed: 02/07/2023]
Abstract
Psychological factors have long been assumed to be involved in the pathogenesis of allergic skin diseases. The effects of psychological stress on allergic contact dermatitis (ACD) have been experimentally well investigated; however, the effects of ACD on stress responses are largely unknown. Here, we report that preceding chronic ACD dramatically affects the behavioral and physiological stress responses to social isolation (a psychological stressor). In male BALB/c mice, social isolation combined with long-standing (>2 months) ACD by repeated hapten application caused characteristic symptoms, including chronic dermatitis from persistent self-scratching, behavioral changes related to fear/anxiety, and elevated serum IgE levels. The symptoms were maintained by social isolation alone without further hapten application after the onset, and were improved by resocialization. Treatment with topical corticosteroids exacerbated chronic scratch dermatitis, whereas it was effective for chronic ACD. These results show that the symptoms represent a de novo development of a specific disease state and not a mere exacerbation of a preexisting allergic inflammation. With this experimental protocol, similar results were obtained in several other strains of mice. This murine model provides a tool for investigating the pathogenesis and treatment of allergic skin disease with psychodermatological aspects.
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Genois A, Haig M, Des Roches A, Sirard A, Le May S, McCuaig CC. Case report of atopic dermatitis with refractory pruritus markedly improved with the novel use of clonidine and trimeprazine. Pediatr Dermatol 2014; 31:76-9. [PMID: 22747704 DOI: 10.1111/j.1525-1470.2012.01756.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report a 6-year-old boy with severe atopic dermatitis and refractory pruritus. The novel use of clonidine, an adrenergic agonist, along with trimeprazine, led to dramatic improvement. This represents the first case report of clonidine's effect in relieving pruritus in atopic dermatitis.
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Affiliation(s)
- Annie Genois
- Faculty of MedicineDepartments of AnesthesiaServices of Allergy and ImmunologyPediatricsDermatology, CHU Sainte JustineDepartment of Nursing, University of Montreal, Montreal, Quebec, Canada
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The kinin B1 receptor mediates alloknesis in a murine model of inflammation. Neurosci Lett 2013; 560:31-5. [PMID: 24355361 DOI: 10.1016/j.neulet.2013.12.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Revised: 12/04/2013] [Accepted: 12/09/2013] [Indexed: 01/02/2023]
Abstract
Noxious stimuli and non-noxious mechanical stimuli elicit itch (alloknesis) instead of pain on skin lesions of patients with atopic dermatitis. We previously found that bradykinin evokes an itch-related scratching response through activation of kinin B1 receptor in skin inflamed using complete Freund's adjuvant. In this study we investigated whether alloknesis is evoked in CFA-inflamed skin and the involvement of kinin receptors. In our results, alloknesis was elicited four days after CFA-inflammation. Furthermore, pretreatment with a B1 receptor antagonist or μ-opioid receptor antagonist significantly reduced alloknesis. In contrast, treatment with a B2 receptor antagonist significantly increased alloknesis. These results suggest that the alloknesis response is mediated by the activation of kinin B1 receptor but antagonized by the B2 receptor in CFA-inflamed mice.
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Wikel S. Ticks and tick-borne pathogens at the cutaneous interface: host defenses, tick countermeasures, and a suitable environment for pathogen establishment. Front Microbiol 2013; 4:337. [PMID: 24312085 PMCID: PMC3833115 DOI: 10.3389/fmicb.2013.00337] [Citation(s) in RCA: 147] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 10/25/2013] [Indexed: 11/21/2022] Open
Abstract
Ticks are unique among hematophagous arthropods by continuous attachment to host skin and blood feeding for days; complexity and diversity of biologically active molecules differentially expressed in saliva of tick species; their ability to modulate the host defenses of pain and itch, hemostasis, inflammation, innate and adaptive immunity, and wound healing; and, the diverse array of infectious agents they transmit. All of these interactions occur at the cutaneous interface in a complex sequence of carefully choreographed host defense responses and tick countermeasures resulting in an environment that facilitates successful blood feeding and establishment of tick-borne infectious agents within the host. Here, we examine diverse patterns of tick attachment to host skin, blood feeding mechanisms, salivary gland transcriptomes, bioactive molecules in tick saliva, timing of pathogen transmission, and host responses to tick bite. Ticks engage and modulate cutaneous and systemic immune defenses involving keratinocytes, natural killer cells, dendritic cells, T cell subpopulations (Th1, Th2, Th17, Treg), B cells, neutrophils, mast cells, basophils, endothelial cells, cytokines, chemokines, complement, and extracellular matrix. A framework is proposed that integrates tick induced changes of skin immune effectors with their ability to respond to tick-borne pathogens. Implications of these changes are addressed. What are the consequences of tick modulation of host cutaneous defenses? Does diversity of salivary gland transcriptomes determine differential modulation of host inflammation and immune defenses and therefore, in part, the clades of pathogens effectively transmitted by different tick species? Do ticks create an immunologically modified cutaneous environment that enhances specific pathogen establishment? Can tick saliva molecules be used to develop vaccines that block pathogen transmission?
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Affiliation(s)
- Stephen Wikel
- Department of Medical Sciences, Frank H. Netter MD School of Medicine, Quinnipiac University Hamden, CT, USA
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