1
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Okutani H, Lo Vecchio S, Arendt-Nielsen L. Mechanisms and treatment of opioid-induced pruritus: Peripheral and central pathways. Eur J Pain 2024; 28:214-230. [PMID: 37650457 DOI: 10.1002/ejp.2180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 08/08/2023] [Accepted: 08/22/2023] [Indexed: 09/01/2023]
Abstract
BACKGROUND AND OBJECTIVE Pruritus (also known as itch) is defined as an unpleasant and irritating sensation of the skin that provokes an urge to scratch or rub. It is well known that opioid administration can cause pruritus, which is paradoxical as itch and pain share overlapping sensory pathways. Because opioids inhibit pain but can cause itching. Significant progress has been made to improve our understanding of the fundamental neurobiology of itch; however, much remains unknown about the mechanisms of opioid-induced pruritus. The prevention and treatment of opioid-induced pruritus remains a challenge in the field of pain management. The objective of this narrative review is to present and discuss the current body of literature and summarize the current understanding of the mechanisms underlying opioid-induced pruritus, and its relationship to analgesia, and possible treatment options. RESULTS The incidence of opioid-induced pruritus differs with different opioids and routes of administration, and the various mechanisms can be broadly divided into peripheral and central. Especially central mechanisms are intricate, even at the level of the spinal dorsal horn. There is evidence that opioid receptor antagonists and mixed agonist and antagonists, especially μ-opioid antagonists and κ-opioid agonists, are effective in relieving opioid-induced pruritus. Various treatments have been used for opioid-induced pruritus; however, most of them are controversial and have conflicting results. CONCLUSION The use of a multimodal analgesic treatment regimen combined with a mixed antagonist and κ agonists, especially μ-opioid antagonists, and κ-opioid agonists, seems to be the current best treatment modality for the management of opioid-induced pruritus and pain. SIGNIFICANCE Opioids remain the gold standard for the treatment of moderate to severe acute pain as well as cancer pain. It is well known that opioid-induced pruritus often does not respond to regular antipruritic treatment, thereby posing a challenge to clinicians in the field of pain management. We believe that our review makes a significant contribution to the literature, as studies on the mechanisms of opioid-induced pruritus and effective management strategies are crucial for the management of these patients.
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Affiliation(s)
- Hiroai Okutani
- Center for Neuroplasticity and Pain, SMI, Department of Health Science and Technology, School of Medicine, Aalborg University, Aalborg, Denmark
- Department of Anesthesiology and Pain Medicine, Hyogo Medical University, Nishinomiya, Hyogo, Japan
| | - Silvia Lo Vecchio
- Center for Neuroplasticity and Pain, SMI, Department of Health Science and Technology, School of Medicine, Aalborg University, Aalborg, Denmark
| | - Lars Arendt-Nielsen
- Center for Neuroplasticity and Pain, SMI, Department of Health Science and Technology, School of Medicine, Aalborg University, Aalborg, Denmark
- Department of Gastroenterology and Hepatology, Aalborg University Hospital, Aalborg, Denmark
- Steno Diabetes Center North Denmark, Clinical Institute, Aalborg University Hospital, Aalborg, Denmark
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2
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Poddar S, Mondal H, Podder I. Aetiology, pathogenesis and management of neuropathic itch: A narrative review with recent updates. Indian J Dermatol Venereol Leprol 2024; 90:5-18. [PMID: 37317726 DOI: 10.25259/ijdvl_846_2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 02/17/2023] [Indexed: 06/16/2023]
Abstract
Neuropathic itch is a relatively common yet under-reported cause of systemic pruritus. It is a debilitating condition often associated with pain, which impairs the patient's quality of life. Although much literature exists about renal and hepatic pruritus, there is a dearth of information and awareness about neuropathic itch. The pathogenesis of neuropathic itch is complex and can result from an insult at any point along the itch pathway, ranging from the peripheral receptors and nerves until the brain. There are several causes of neuropathic itch, many of which do not produce any skin lesions and are thus, often missed. A detailed history and clinical examination are necessary for the diagnosis, while laboratory and radiologic investigations may be needed in select cases. Several therapeutic strategies currently exist involving both non-pharmacological and pharmacological measures, the latter including topical, systemic, and invasive options. Further research is ongoing to clarify its pathogenesis and to design newer targeted therapies with minimal adverse effects. This narrative review highlights the current understanding of this condition, focusing on its causes, pathogenesis, diagnosis, and management, along with newer investigational drugs.
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Affiliation(s)
- Shreya Poddar
- Department of Dermatology, Asansol District Hospital, Asansol, West Bengal, India
| | - Himel Mondal
- Department of Physiology, All India Institute of Medical Sciences (AIIMS), Deoghar, Jharkhand, India
| | - Indrashis Podder
- Department of Dermatology, College of Medicine & Sagore Dutta Hospital, Kolkata, West Bengal, India
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3
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Li JN, Wu XM, Zhao LJ, Sun HX, Hong J, Wu FL, Chen SH, Chen T, Li H, Dong YL, Li YQ. Central medial thalamic nucleus dynamically participates in acute itch sensation and chronic itch-induced anxiety-like behavior in male mice. Nat Commun 2023; 14:2539. [PMID: 37137899 PMCID: PMC10156671 DOI: 10.1038/s41467-023-38264-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 04/20/2023] [Indexed: 05/05/2023] Open
Abstract
Itch is an annoying sensation consisting of both sensory and emotional components. It is known to involve the parabrachial nucleus (PBN), but the following transmission nodes remain elusive. The present study identified that the PBN-central medial thalamic nucleus (CM)-medial prefrontal cortex (mPFC) pathway is essential for itch signal transmission at the supraspinal level in male mice. Chemogenetic inhibition of the CM-mPFC pathway attenuates scratching behavior or chronic itch-related affective responses. CM input to mPFC pyramidal neurons is enhanced in acute and chronic itch models. Specifically chronic itch stimuli also alter mPFC interneuron involvement, resulting in enhanced feedforward inhibition and a distorted excitatory/inhibitory balance in mPFC pyramidal neurons. The present work underscores CM as a transmit node of the itch signal in the thalamus, which is dynamically engaged in both the sensory and affective dimensions of itch with different stimulus salience.
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Affiliation(s)
- Jia-Ni Li
- Department of Anatomy, Histology and Embryology, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China
| | - Xue-Mei Wu
- Department of Anatomy, Histology and Embryology, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China
- Department of Human Anatomy, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, 610041, China
| | - Liu-Jie Zhao
- Department of Anatomy, Histology and Embryology, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China
- Department of Anatomy, Basic Medical College, Zhengzhou University, Zhengzhou, 450001, China
| | - Han-Xue Sun
- Department of Anatomy, Histology and Embryology, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China
- Department of Human Anatomy, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, 350122, China
| | - Jie Hong
- Department of Anatomy, Histology and Embryology, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China
- Department of Human Anatomy, Baotou Medical College Inner Mongolia University of Science and Technology, Baotou, 014040, China
| | - Feng-Ling Wu
- Department of Anatomy, Histology and Embryology, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China
- Department of Anatomy, Basic Medical College, Zhengzhou University, Zhengzhou, 450001, China
| | - Si-Hai Chen
- Department of Anatomy, Histology and Embryology, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China
- Department of Anatomy, Basic Medical College, Zhengzhou University, Zhengzhou, 450001, China
| | - Tao Chen
- Department of Anatomy, Histology and Embryology, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China
| | - Hui Li
- Department of Anatomy, Histology and Embryology, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China
| | - Yu-Lin Dong
- Department of Anatomy, Histology and Embryology, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China.
| | - Yun-Qing Li
- Department of Anatomy, Histology and Embryology, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China.
- Department of Human Anatomy, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, 610041, China.
- Department of Anatomy, Basic Medical College, Zhengzhou University, Zhengzhou, 450001, China.
- Department of Human Anatomy, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, 350122, China.
- Department of Human Anatomy, Baotou Medical College Inner Mongolia University of Science and Technology, Baotou, 014040, China.
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4
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Zhang TT, Guo SS, Wang HY, Jing Q, Yi X, Hu ZH, Yu XR, Xu TL, Liu MG, Zhao X. An Anterior Cingulate Cortex-to-Midbrain Projection Controls Chronic Itch in Mice. Neurosci Bull 2022; 39:793-807. [PMID: 36528690 PMCID: PMC10169993 DOI: 10.1007/s12264-022-00996-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 08/26/2022] [Indexed: 12/23/2022] Open
Abstract
AbstractItch is an unpleasant sensation that provokes the desire to scratch. While acute itch serves as a protective system to warn the body of external irritating agents, chronic itch is a debilitating but poorly-treated clinical disease leading to repetitive scratching and skin lesions. However, the neural mechanisms underlying the pathophysiology of chronic itch remain mysterious. Here, we identified a cell type-dependent role of the anterior cingulate cortex (ACC) in controlling chronic itch-related excessive scratching behaviors in mice. Moreover, we delineated a neural circuit originating from excitatory neurons of the ACC to the ventral tegmental area (VTA) that was critically involved in chronic itch. Furthermore, we demonstrate that the ACC→VTA circuit also selectively modulated histaminergic acute itch. Finally, the ACC neurons were shown to predominantly innervate the non-dopaminergic neurons of the VTA. Taken together, our findings uncover a cortex–midbrain circuit for chronic itch-evoked scratching behaviors and shed novel insights on therapeutic intervention.
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Affiliation(s)
- Ting-Ting Zhang
- Department of Anesthesiology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China
| | - Su-Shan Guo
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Hui-Ying Wang
- Department of Anesthesiology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China
| | - Qi Jing
- Department of Anesthesiology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China
| | - Xin Yi
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Zi-Han Hu
- Department of Anesthesiology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China
| | - Xin-Ren Yu
- Department of Anesthesiology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China
| | - Tian-Le Xu
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
- Center for Brain Science of Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
| | - Ming-Gang Liu
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
- Center for Brain Science of Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China.
| | - Xuan Zhao
- Department of Anesthesiology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China.
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5
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Wu GY, Zheng XX, Zhao SL, Wang Y, Jiang S, Wang YS, Yi YL, Yao J, Wen HZ, Liu J, Li HL, Sui JF. The prelimbic cortex regulates itch processing by controlling attentional bias. iScience 2022; 26:105829. [PMID: 36619983 PMCID: PMC9816985 DOI: 10.1016/j.isci.2022.105829] [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: 04/04/2022] [Revised: 10/31/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
Itch is a complex and unpleasant sensory experience. Recent studies have begun to investigate the neural mechanisms underlying the modulation of sensory and emotional components of itch in the brain. However, the key brain regions and neural mechanism involved in modulating the attentional processing of itch remain elusive. Here, we showed that the prelimbic cortex (PrL) is associated with itch processing and that the manipulation of itch-responsive neurons in the PrL significantly disrupted itch-induced scratching. Interestingly, we found that increasing attentional bias toward a distracting stimulus could disturb itch processing. We also demonstrated the existence of a population of attention-related neurons in the PrL that drive attentional bias to regulate itch processing. Importantly, itch-responsive neurons and attention-related neurons significantly overlapped in the PrL and were mutually interchangeable in the regulation of itch processing at the cellular activity level. Our results revealed that the PrL regulates itch processing by controlling attentional bias.
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Affiliation(s)
- Guang-Yan Wu
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China,Department of Physiology, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China,Corresponding author
| | - Xiao-Xia Zheng
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Shan-Lan Zhao
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Yi Wang
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Shan Jiang
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Yi-Song Wang
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Yi-Lun Yi
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Juan Yao
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Hui-Zhong Wen
- Department of Neurobiology, College of Basic Medical Sciences, Chongqing Key Laboratory of Neurobiology, Army Medical University, Chongqing 400038, China
| | - Ju Liu
- Department of Foreign Languages, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Hong-Li Li
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China,Corresponding author
| | - Jian-Feng Sui
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China,Department of Physiology, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China,Corresponding author
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6
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Ryu K, Heo Y, Lee Y, Jeon H, Namkung W. Berbamine Reduces Chloroquine-Induced Itch in Mice through Inhibition of MrgprX1. Int J Mol Sci 2022; 23:ijms232214321. [PMID: 36430803 PMCID: PMC9698483 DOI: 10.3390/ijms232214321] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/14/2022] [Accepted: 11/17/2022] [Indexed: 11/22/2022] Open
Abstract
Chloroquine (CQ) is an antimalaria drug that has been widely used for decades. However, CQ-induced pruritus remains one of the major obstacles in CQ treatment for uncomplicated malaria. Recent studies have revealed that MrgprX1 plays an essential role in CQ-induced itch. To date, a few MrgprX1 antagonists have been discovered, but they are clinically unavailable or lack selectivity. Here, a cell-based high-throughput screening was performed to identify novel antagonists of MrgprX1, and the screening of 2543 compounds revealed two novel MrgprX1 inhibitors, berbamine and closantel. Notably, berbamine potently inhibited CQ-mediated MrgprX1 activation (IC50 = 1.6 μM) but did not alter the activity of other pruritogenic GPCRs. In addition, berbamine suppressed the CQ-mediated phosphorylation of ERK1/2. Interestingly, CQ-induced pruritus was significantly reduced by berbamine in a dose-dependent manner, but berbamine had no effect on histamine-induced, protease-activated receptors 2-activating peptide-induced, and deoxycholic acid-induced itch in mice. These results suggest that berbamine is a novel, potent, and selective antagonist of MrgprX1 and may be a potential drug candidate for the development of therapeutic agents to treat CQ-induced pruritus.
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7
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Mamuladze T, Kim BS. The Sensation of Itch: From Biological Discovery to Medical Treatment. J Invest Dermatol 2021; 142:21-22. [PMID: 34801533 DOI: 10.1016/j.jid.2021.10.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 10/18/2021] [Indexed: 10/19/2022]
Affiliation(s)
- Tornike Mamuladze
- Division of Biology and Biomedical Sciences (DBBS), Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Brian S Kim
- Division of Biology and Biomedical Sciences (DBBS), Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA; Center for the Study of Itch & Sensory Disorders, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA; Division of Dermatology, Department of Medicine, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA; Department of Anesthesiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA.
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8
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Weisshaar E, Szepietowski JC, Bernhard JD, Hait H, Legat FJ, Nattkemper L, Reich A, Sadoghi B, Sciascia TR, Zeidler C, Yosipovitch G, Ständer S. Efficacy and safety of oral nalbuphine extended release in prurigo nodularis: results of a phase 2 randomized controlled trial with an open-label extension phase. J Eur Acad Dermatol Venereol 2021; 36:453-461. [PMID: 34780095 DOI: 10.1111/jdv.17816] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 10/22/2021] [Indexed: 01/11/2023]
Abstract
BACKGROUND Treatment of prurigo nodularis (PN) is challenging and new treatment options are needed. OBJECTIVE To evaluate the efficacy and safety of two oral doses of the kappa opioid agonist and mu opioid antagonist nalbuphine extended release (NAL-ER) tablets in a phase 2, multicentre, randomized, double-blind, placebo-controlled trial with an open-label, 50-week extension phase. METHODS Subjects with moderate-to-severe PN were randomized to NAL-ER 81 mg (NAL-ER81) or 162 mg (NAL-ER162) tablets twice-daily or placebo for 8 weeks of stable dosing following a 2-week titration period. Subjects completing Week 10 with a Worst Itch Numerical Rating Scale (WI-NRS) score ≥5 at the time of rollover (or during the observation period) were eligible for open-label treatment. RESULTS Of 63 randomized subjects, 62 were treated and comprised the modified intent-to-treat population (MITT), 50 completed 10 weeks of treatment. In the MITT analysis, 8 subjects (44.4%) treated with NAL-ER162 (P = 0.32) and 6 (27.3%) treated with NAL-ER81 (P = 0.78) achieved ≥30% reduction from baseline in 7-day WI-NRS at Week 10 (primary efficacy endpoint) vs. 8 (36.4%) in the placebo group. Itch reduction was significant among 8/12 (66.7%) subjects completing Week 10 treated with NAL-ER162 vs. placebo (8/20, 40.0%; P = 0.03). Additionally, 6 subjects (33.3%) treated with NAL-ER162 and 3 (13.6%) treated with NAL-ER81 achieved ≥50% reduction from baseline in 7-day WI-NRS at Week 10 (coprimary endpoint). Extended open-label treatment was associated with further improvements in itch reduction and favourable changes in PN lesion activity as assessed by Prurigo Activity Score. Adverse events occurred predominantly during dose titration and were of mild-to-moderate severity. The safety profile did not change with extended open-label treatment. CONCLUSION In adult subjects with PN, oral treatment with NAL-ER 162 mg twice daily provided measurable anti-pruritic efficacy in subjects completing ≥10 weeks of treatment and was well tolerated (ClinicalTrials.gov: NCT02174419).
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Affiliation(s)
- E Weisshaar
- Occupational Dermatology, Department of Dermatology, Heidelberg University Hospital, Heidelberg, Germany
| | - J C Szepietowski
- Department of Dermatology, Venereology and Allergology, Wroclaw Medical University, Wroclaw, Poland
| | - J D Bernhard
- Department of Dermatology, University of Massachusetts Medical School, Worcester, MA, USA
| | - H Hait
- Trevi Therapeutics, Inc., New Haven, CT, USA
| | - F J Legat
- Department of Dermatology, Medical University of Graz, Graz, Austria
| | - L Nattkemper
- Department of Dermatology, Miller School of Medicine and Miami Itch Center, Miami, FL, USA
| | - A Reich
- Department of Dermatology, Institute of Medical Sciences, Medical College of Rzeszów University, Rzeszów, Poland
| | - B Sadoghi
- Department of Dermatology, Medical University of Graz, Graz, Austria
| | | | - C Zeidler
- Department of Dermatology and Center for Chronic Pruritus, University Hospital Münster, Münster, Germany
| | - G Yosipovitch
- Department of Dermatology, Miller School of Medicine and Miami Itch Center, Miami, FL, USA
| | - S Ständer
- Department of Dermatology and Center for Chronic Pruritus, University Hospital Münster, Münster, Germany
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9
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Chronic itch induced by thalamic deep brain stimulation: a case for a central itch centre. J Transl Med 2021; 19:430. [PMID: 34656120 PMCID: PMC8520252 DOI: 10.1186/s12967-021-03110-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 10/06/2021] [Indexed: 11/28/2022] Open
Abstract
Background Central itch syndrome has been previously described in conditions such as stroke. The neurophysiology of central itch syndrome has been investigated in non-human primates but remains incompletely understood. Methods We report an observational study of a rare case of severe central itch following thalamic deep brain stimulation and postulate the location of the central itch centre in humans. Results The patient was a 47-year-old female, with congenital spinal malformations, multiple previous corrective spinal surgeries and a 30-year history of refractory neuropathic pain in her back and inferior limbs. Following multidisciplinary pain assessment and recommendation, she was referred for spinal cord stimulation, but the procedure failed technically due to scarring related to her multiple previous spinal surgeries. She was therefore referred to our centre and underwent bilateral deep brain stimulation (DBS) of the ventral posterolateral nucleus of the thalamus for management of her chronic pain. Four weeks after switching on the stimulation, the patient reported significant improvement in her pain but developed a full body progressive itch which was then complicated with a rash. Common causes of skin eczema were ruled out by multiple formal dermatological evaluation. A trial of unilateral “off stimulation” was performed showing improvement of the itchy rash. Standard and normalized brain atlases were used to localize the active stimulating contact within the thalamus at a location we postulate as the central itch centre. Conclusions Precise stereotactic imaging points to the lateral portion of the ventral posterolateral and posteroinferior nuclei of the thalamus as critical in the neurophysiology of itch in humans.
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10
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Tseng PY, Hoon MA. Specific β-Defensins Stimulate Pruritus through Activation of Sensory Neurons. J Invest Dermatol 2021; 142:594-602. [PMID: 34480893 DOI: 10.1016/j.jid.2021.07.178] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 07/02/2021] [Accepted: 07/30/2021] [Indexed: 12/12/2022]
Abstract
Pruritus is a common symptom of dermatological disorders and has a major negative impact on QOL. Previously, it was suggested that human β-defensin peptides elicit itch through the activation of mast cells. In this study, we investigated in more detail the mechanisms by which β-defensins induce itch by defining the receptors activated by these peptides in humans and mice, by establishing their action in vivo, and by examining their expression in inflammatory dermal diseases. We found that elevated expression of DEFB103 is highly correlated with skin lesions in psoriasis and atopic dermatitis. We showed that the peptide encoded by this gene and related genes activate Mas-related G protein-coupled receptors with different potencies that are related to their charge density. Furthermore, we establish that although these peptides can activate mast cells, they also activate sensory neurons, with the former cells being dispensable for itch reactions in mice. Together, our studies highlight that specific β-defensins are likely endogenous pruritogens that can directly stimulate sensory neurons.
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Affiliation(s)
- Pang-Yen Tseng
- Molecular Genetics Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, USA
| | - Mark A Hoon
- Molecular Genetics Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, USA.
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11
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Abstract
Introduction: Cinnamaldehyde (CA) elicits itch sensation in humans. We investigated
if CA elicits scratching behavior in mice and determined the roles for
TRPV1, TRPA1, and TRPV4. Materials and Methods: Scratching behavior elicited by intradermal injection of CA was
assessed in wildtype (WT) mice and knockout (KO) mice lacking TRPV1, TRPA1,
TRPV4, or deficient in mast cells. We also assessed scratching and wet dog
shakes elicited by low-threshold mechanical stimulation of skin treated
topically with CA or vehicle. Using calcium imaging we tested if CA
activates dorsal root ganglion (DRG) neurons of each genotype. Results: Intradermal cheek injection of CA elicited dose-dependent hindlimb
scratch bouts, with fewer forelimb wipes and facial groom bouts that were
not dose-dependent. CA elicited significantly fewer scratch bouts in TRPV1
and TRPV4 KO mice, but not TRPA1KOs, compared with WTs. There were no sex
differences across genotypes. The histamine H1 antagonist cetirizine did not
affect CA-evoked scratching, which was normal in mast cell deficient mice,
indicating lack of histamine involvement. Scores for alloknesis were
significantly greater following topical application of CA compared with
vehicle. Post-CA alloknesis scores were significantly higher in TRPV4KOs of
both sexes and in female TRPV1 and TRPA1KOs, compared with WTs. Low
threshold mechanical stimuli also elicited significantly more wet dog shakes
in mice treated topically with 20% CA, with significantly fewer in TRPV1,
TRPA1, and TRPV4KOs compared with WTs. In calcium imaging studies, CA
excited 24% of WT DRG cells, significantly fewer (11.5%) in cells from
TRPV4KOs, and none in TRPA1KOs. Responses of cells of all genotypes
exhibited significant sensitization to repeated CA stimulation.
Sensitization was significantly enhanced by IL-4, which itself excited 16%
of WT DRG cells and none from TRPA1KOs. Discussion: The results indicate that TRPA1 is dispensable for CA-evoked
scratching, which depends partly on TRPV1 and TRPV4.
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12
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Interleukin-31 and Pruritic Skin. J Clin Med 2021; 10:jcm10091906. [PMID: 33924978 PMCID: PMC8124688 DOI: 10.3390/jcm10091906] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 04/22/2021] [Accepted: 04/23/2021] [Indexed: 12/26/2022] Open
Abstract
Skin inflammation often evokes pruritus, which is the major subjective symptom in many inflammatory skin diseases such as atopic dermatitis and prurigo nodularis. Pruritus or itch is a specific sensation found only in the skin. Recent studies have stressed the pivotal role played by interleukin-31 (IL-31) in the sensation of pruritus. IL-31 is produced by various cells including T helper 2 cells, macrophages, dendritic cells and eosinophils. IL-31 signals via a heterodimeric receptor composed of IL-31 receptor A (IL-31RA) and oncostatin M receptor β. Recent clinical trials have shown that the anti-IL-31RA antibody nemolizumab can successfully decrease pruritus in patients with atopic dermatitis and prurigo nodularis. The IL-31 pathway and pruritic skin are highlighted in this review article.
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Garcovich S, Maurelli M, Gisondi P, Peris K, Yosipovitch G, Girolomoni G. Pruritus as a Distinctive Feature of Type 2 Inflammation. Vaccines (Basel) 2021; 9:vaccines9030303. [PMID: 33807098 PMCID: PMC8005108 DOI: 10.3390/vaccines9030303] [Citation(s) in RCA: 69] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 03/17/2021] [Accepted: 03/19/2021] [Indexed: 12/13/2022] Open
Abstract
Pruritus is a common symptom of several skin diseases, both inflammatory and neoplastic. Pruritus might have a tremendous impact on patients’ quality of life and strongly interfere with sleep, social, and work activities. We review the role of type-2 inflammation and immunity in the pathogenesis of chronic pruritic conditions of the skin. Type 2 cytokines, including IL-4, IL-13, thymic stromal lymphopoietin, periostin, IL-31, IL-25, and IL-33 are released by mast cells, innate lymphoid cells 2, keratinocytes, and type 2 T lymphocytes, and are master regulators of chronic itch. These cytokines might act as direct pruritogen on primary sensory neurons (pruriceptors) or alter the sensitivity to other itch mediators Type 2 inflammation- and immunity-dominated skin diseases, including atopic dermatitis, prurigo nodularis, bullous pemphigoid, scabies, parasitic diseases, urticaria, and Sézary syndrome are indeed conditions associated with most severe pruritus. In contrast, in other skin diseases, such as scleroderma, lupus erythematosus, hidradenitis suppurativa, and acne, type 2 inflammation is less represented, and pruritus is milder or variable. Th2 inflammation and immunity evolved to protect against parasites, and thus, the scratching response evoked by pruritus might have developed to alert about the presence and to remove parasites from the skin surface.
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Affiliation(s)
- Simone Garcovich
- Dermatology, Università Cattolica del Sacro Cuore, 00168 Rome, Italy;
- Dermatology Unit, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy
- Correspondence:
| | - Martina Maurelli
- Section of Dermatology and Venereology, Department of Medicine, University of Verona, 37126 Verona, Italy; (M.M.); (P.G.); (G.G.)
| | - Paolo Gisondi
- Section of Dermatology and Venereology, Department of Medicine, University of Verona, 37126 Verona, Italy; (M.M.); (P.G.); (G.G.)
| | - Ketty Peris
- Dermatology, Università Cattolica del Sacro Cuore, 00168 Rome, Italy;
- Dermatology Unit, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy
| | - Gil Yosipovitch
- Miami Itch Center, Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, Miller School of Medicine, University of Miami, Miami, FL 33136, USA;
| | - Giampiero Girolomoni
- Section of Dermatology and Venereology, Department of Medicine, University of Verona, 37126 Verona, Italy; (M.M.); (P.G.); (G.G.)
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14
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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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15
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Pereira MP, Wiegmann H, Agelopoulos K, Ständer S. Neuropathic Itch: Routes to Clinical Diagnosis. Front Med (Lausanne) 2021; 8:641746. [PMID: 33732722 PMCID: PMC7959783 DOI: 10.3389/fmed.2021.641746] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 02/03/2021] [Indexed: 01/08/2023] Open
Abstract
Neuropathic itch occurs due to damage of neurons of the peripheral or central nervous system. Several entities, including metabolic, neurodegenerative, orthopedic, infectious, autoimmune, malignant, and iatrogenic conditions, may affect the somatosensory system and induce neuropathic itch. Due to the complex nature of neuropathic itch, particularly concerning its clinical presentation and possible etiological factors, diagnostic work-up of this condition is challenging. A detailed medical history, especially in regard to the itch, and a comprehensive physical examination are relevant to detect characteristic signs and symptoms of neuropathic itch and to rule out other possible causes for chronic itch. Complementary diagnostic exams, especially laboratory tests, determination of the intraepidermal nerve fiber density via a skin biopsy and radiological examinations may be indicated to confirm the diagnosis of neuropathic itch and to identify underlying etiological factors. Functional assessments such as quantitative sensory testing, nerve conduction studies, evoked potentials, or microneurography may be considered in particular cases. This review article provides a comprehensive overview of the diagnostic work-up recommended for patients with neuropathic itch.
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Affiliation(s)
- Manuel Pedro Pereira
- Department of Dermatology and Center for Chronic Pruritus, University Hospital Münster, Münster, Germany
| | - Henning Wiegmann
- Department of Dermatology and Center for Chronic Pruritus, University Hospital Münster, Münster, Germany
| | - Konstantin Agelopoulos
- Department of Dermatology and Center for Chronic Pruritus, University Hospital Münster, Münster, Germany
| | - Sonja Ständer
- Department of Dermatology and Center for Chronic Pruritus, University Hospital Münster, Münster, Germany
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16
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Li JN, Ren JH, Zhao LJ, Wu XM, Li H, Dong YL, Li YQ. Projecting neurons in spinal dorsal horn send collateral projections to dorsal midline/intralaminar thalamic complex and parabrachial nucleus. Brain Res Bull 2021; 169:184-195. [PMID: 33508400 DOI: 10.1016/j.brainresbull.2021.01.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 01/12/2021] [Accepted: 01/15/2021] [Indexed: 10/22/2022]
Abstract
Itch is an annoying sensation that always triggers scratching behavior, yet little is known about its transmission pathway in the central nervous system. Parabrachial nucleus (PBN), an essential transmission nucleus in the brainstem, has been proved to be the first relay station in itch sensation. Meanwhile, dorsal midline/intralaminar thalamic complex (dMITC) is proved to be activated with nociceptive stimuli. However, whether the PBN-projecting neurons in spinal dorsal horn (SDH) send collateral projections to dMITC, and whether these projections involve in itch remain unknown. In the present study, a double retrograde tracing method was applied when the tetramethylrhodamine-dextran (TMR) was injected into the dMITC and Fluoro-gold (FG) was injected into the PBN, respectively. Immunofluorescent staining for NeuN, substance P receptor (SPR), substance P (SP), or FOS induced by itch or pain stimulations with TMR and FG were conducted to provide morphological evidence. The results revealed that TMR/FG double-labeled neurons could be predominately observed in superficial laminae and lateral spinal nucleus (LSN) of SDH; Meanwhile, most of the collateral projection neurons expressed SPR and some of them expressed FOS in acute itch model induced by histamine. The present results implicated that some of the SPR-expressing neurons in SDH send collateral projections to the dMITC and PBN in itch transmission, which might be involved in itch related complex affective/emotional processing to the higher brain centers.
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Affiliation(s)
- Jia-Ni Li
- Department of Anatomy, Histology and Embryology & K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China
| | - Jia-Hao Ren
- Department of Anatomy, Histology and Embryology & K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China
| | - Liu-Jie Zhao
- Department of Anatomy, Basic Medical College, Zhengzhou University, Zhengzhou, 450001, China
| | - Xue-Mei Wu
- Department of Human Anatomy, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu, 610041, China
| | - Hui Li
- Department of Anatomy, Histology and Embryology & K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China
| | - Yu-Lin Dong
- Department of Anatomy, Histology and Embryology & K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China.
| | - Yun-Qing Li
- Department of Anatomy, Histology and Embryology & K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China; Department of Anatomy, Basic Medical College, Zhengzhou University, Zhengzhou, 450001, China; Key Laboratory of Brain Science Research and Transformation in Tropical Environment of Hainan Province, Haikou, China.
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17
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Najafi P, Ben Salem D, Carré JL, Misery L, Dufor O. Functional and anatomical brain connectivity in psoriasis patients and healthy controls: a pilot brain imaging study after exposure to mentally induced itch. J Eur Acad Dermatol Venereol 2020; 34:2557-2565. [PMID: 32267024 DOI: 10.1111/jdv.16441] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 03/10/2020] [Indexed: 01/08/2023]
Abstract
BACKGROUND Despite the prevalence of psoriasis, the processing of itch in psoriasis and its impact on the central nervous system (CNS) remain unclear. OBJECTIVE We studied the influence of psoriasis on the CNS using magnetic resonance imaging techniques (fMRI and DTI, respectively) to investigate whether mentally induced itch can modify the functional connectivity or the white matter microstructure of the brain. METHODS Fourteen patients with chronic psoriasis and 15 healthy controls were recruited. Itch was mentally induced in subjects by videos showing others scratching themselves. RESULTS The observation of functional connectivity during the viewing the video revealed an interconnected network of brain regions that are more strongly coupled in psoriasis patients than in healthy controls. This network links the cerebellum, the thalami, the anteroposterior cingulum, the inferior parietal lobules, the middle temporal poles and the parahippocampal, hippocampal, lingual and supramarginal gyri. We also found connections with the right precuneus and both left insula and superior temporal gyrus. The DTI analysis showed that chronic itch affects the microstructure of white matter, including the anterior thalamic radiations, the superior and inferior longitudinal fasciculi, the corticospinal tracts, the cingulum, the external capsules, the inferior frontal-occipital fasciculi and both minor and major forceps. CONCLUSION Our results indicate that there could exist a network which is more interconnected in psoriasis patients. Among two building blocks of this network, the subnetwork encoding the perception and control of itch sensation is more affected than the subnetwork representing mentalizing and empathy. With an approach consisting of measuring microstructural changes at a local level in the brain, we also contradict the findings obtained with global measures which stated that chronic psoriasis cannot alter the anatomy of the brain. This confirms that itchy pathophysiological conditions have similar effects on functional and structural connectivity as those observed in chronic pain.
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Affiliation(s)
| | - D Ben Salem
- Univ Brest, LATIM, Brest, France.,University Hospital of Brest, Brest, France
| | - J-L Carré
- Univ Brest, LIEN, Brest, France.,University Hospital of Brest, Brest, France
| | - L Misery
- Univ Brest, LIEN, Brest, France.,University Hospital of Brest, Brest, France
| | - O Dufor
- Univ Brest, LIEN, Brest, France
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18
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Schricker S, Weisshaar E, Kupfer J, Mettang T. Prevalence of Pruritus in a Single Cohort of Long-term Kidney Transplant Recipients. Acta Derm Venereol 2020; 100:adv00066. [PMID: 32052851 PMCID: PMC9128945 DOI: 10.2340/00015555-3421] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/10/2020] [Indexed: 11/16/2022] Open
Abstract
is missing (Short communication).
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Affiliation(s)
- Severin Schricker
- Department of Internal Medicine, Division of General Internal Medicine and Nephrology, Robert-Bosch-Hosptial, DE-70376 Stuttgart, Germany.
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19
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Vincenzi B, Trower M, Duggal A, Guglielmini P, Harris P, Jackson D, Lacouture ME, Ratti E, Tonini G, Wood A, Ständer S. Neurokinin-1 antagonist orvepitant for EGFRI-induced pruritus in patients with cancer: a randomised, placebo-controlled phase II trial. BMJ Open 2020; 10:e030114. [PMID: 32034016 PMCID: PMC7045265 DOI: 10.1136/bmjopen-2019-030114] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
OBJECTIVE To evaluate the efficacy of orvepitant (10 or 30 mg given once daily, orally for 4 weeks), a neurokinin-1 receptor antagonist, compared with placebo in reducing the intensity of epidermal growth factor receptor inhibitor (EGFRI)-induced intense pruritus. DESIGN Randomised, double-blind, placebo-controlled clinical trial. SETTING 15 hospitals in Italy and five hospitals in the UK. PARTICIPANTS 44 patients aged ≥18 years receiving an EGFRI for a histologically confirmed malignant solid tumour and experiencing moderate or intense pruritus after EGFRI treatment. INTERVENTION 30 or 10 mg orvepitant or placebo tablets once daily for 4 weeks (randomised 1:1:1). PRIMARY AND SECONDARY OUTCOME MEASURES The primary endpoint was change from baseline in mean patient-recorded numerical rating scale (NRS) score (over the last three recordings) at week 4. Secondary outcome measures were NRS score, verbal rating scale score, Skindex-16 and Leeds Sleep Evaluation Questionnaire at each study visit (baseline, weeks 1, 4, 8); rescue medication use; EGFRI dose reduction; and study withdrawal because of intense uncontrolled pruritus. RESULTS The trial was terminated early because of recruitment challenges; only 44 of the planned 90 patients were randomised. All patients were analysed for efficacy and safety. Mean NRS score change from baseline to week 4 was -2.78 (SD: 2.64) points in the 30 mg group, -3.04 (SD: 3.06) points in the 10 mg group and -3.21 (SD: 1.77) points in the placebo group; the difference between orvepitant and placebo was not statistically significant. No safety signal was detected. Adverse events related to orvepitant (asthenia, dizziness, dry mouth, hyperhidrosis) were all of mild or moderate severity. CONCLUSIONS Orvepitant was safe and well tolerated. No difference in NRS score between the orvepitant and placebo groups was observed at the week 4 primary endpoint. A number of explanations for this outcome are possible. TRIAL REGISTRATION NUMBER EudraCT2013-002763-25.
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Affiliation(s)
- Bruno Vincenzi
- Medical Oncology, Universita Campus Bio-Medico di Roma Facolta di Medicina e Chirurgia, Roma, Italy
| | | | - Ajay Duggal
- Adnovate Clinical Development Strategies, East Sussex, UK
| | | | | | | | - Mario E Lacouture
- Department of Dermatology, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | | | - Giuseppe Tonini
- Medical Oncology, Universita Campus Bio-Medico di Roma Facolta di Medicina e Chirurgia, Roma, Italy
| | | | - Sonja Ständer
- Center for Chronic Pruritus, University Hospital Münster, Münster, Germany
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20
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Avila C, Massick S, Kaffenberger BH, Kwatra SG, Bechtel M. Cannabinoids for the treatment of chronic pruritus: A review. J Am Acad Dermatol 2020; 82:1205-1212. [PMID: 31987788 DOI: 10.1016/j.jaad.2020.01.036] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 01/15/2020] [Accepted: 01/18/2020] [Indexed: 11/17/2022]
Abstract
Medical marijuana is becoming widely available to patients in the United States, and with recreational marijuana now legalized in many states, patient interest is on the rise. The endocannabinoid system plays an important role in skin homeostasis in addition to broader effects on neurogenic responses such as pruritus and nociception, inflammation, and immune reactions. Numerous studies of in vitro and animal models have provided insight into the possible mechanisms of cannabinoid modulation on pruritus, with the most evidence behind neuronal modulation of peripheral itch fibers and centrally acting cannabinoid receptors. In addition, human studies, although limited due to differences in the cannabinoids used, disease models, and delivery method, have consistently shown significant reductions in both scratching and symptoms in chronic pruritus. Clinical studies have shown a reduction in pruritus in several dermatologic (atopic dermatitis, psoriasis, asteatotic eczema, prurigo nodularis, and allergic contact dermatitis) and systemic (uremic pruritus and cholestatic pruritus) diseases. These preliminary human studies warrant controlled trials to confirm the benefit of cannabinoids for treatment of pruritus and to standardize treatment regimens and indications. In patients who have refractory chronic pruritus after standard therapies, cannabinoid formulations may be considered as an adjuvant therapy where it is legal.
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Affiliation(s)
- Christina Avila
- Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio
| | - Susan Massick
- Division of Dermatology, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | | | - Shawn G Kwatra
- Division of Dermatology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Mark Bechtel
- Division of Dermatology, The Ohio State University Wexner Medical Center, Columbus, Ohio.
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Pogatzki-Zahn EM, Pereira MP, Cremer A, Zeidler C, Dreyer T, Riepe C, Wempe C, Lotts T, Segelcke D, Ringkamp M, Kremer AE, Agelopoulos K, Ständer S. Peripheral Sensitization and Loss of Descending Inhibition Is a Hallmark of Chronic Pruritus. J Invest Dermatol 2020; 140:203-211.e4. [DOI: 10.1016/j.jid.2019.05.029] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 04/26/2019] [Accepted: 05/21/2019] [Indexed: 01/25/2023]
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22
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Metz M. Treatments for chronic pruritus outside of the box. Exp Dermatol 2019; 28:1476-1481. [DOI: 10.1111/exd.14007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 06/17/2019] [Accepted: 07/11/2019] [Indexed: 12/19/2022]
Affiliation(s)
- Martin Metz
- Department of Dermatology, Venereology and Allergology Charité ‐ Universitätsmedizin Berlin Berlin Germany
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23
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Belinskaia DA, Belinskaia MA, Barygin OI, Vanchakova NP, Shestakova NN. Psychotropic Drugs for the Management of Chronic Pain and Itch. Pharmaceuticals (Basel) 2019; 12:ph12020099. [PMID: 31238561 PMCID: PMC6631469 DOI: 10.3390/ph12020099] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Revised: 06/19/2019] [Accepted: 06/21/2019] [Indexed: 12/11/2022] Open
Abstract
Clinical observations have shown that patients with chronic neuropathic pain or itch exhibit symptoms of increased anxiety, depression and cognitive impairment. Such patients need corrective therapy with antidepressants, antipsychotics or anticonvulsants. It is known that some psychotropic drugs are also effective for the treatment of neuropathic pain and pruritus syndromes due to interaction with the secondary molecular targets. Our own clinical studies have identified antipruritic and/or analgesic efficacy of the following compounds: tianeptine (atypical tricyclic antidepressant), citalopram (selective serotonin reuptake inhibitor), mianserin (tetracyclic antidepressant), carbamazepine (anticonvulsant), trazodone (serotonin antagonist and reuptake inhibitor), and chlorprothixene (antipsychotic). Venlafaxine (serotonin-norepinephrine reuptake inhibitor) is known to have an analgesic effect too. The mechanism of such effect of these drugs is not fully understood. Herein we review and correlate the literature data on analgesic/antipruritic activity with pharmacological profile of these compounds.
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Affiliation(s)
- Daria A Belinskaia
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, pr. Torez 44, St. Petersburg 194223, Russia.
| | - Mariia A Belinskaia
- International Centre for Neurotherapeutics, Dublin City University, Glasnevin, Dublin 9, Ireland.
| | - Oleg I Barygin
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, pr. Torez 44, St. Petersburg 194223, Russia.
| | - Nina P Vanchakova
- Department of Pedagogy and Psychology, Faculty of Postgraduate Education, First Pavlov State Medical University, L'va Tolstogo str. 6-8, St. Petersburg 197022, Russia.
| | - Natalia N Shestakova
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, pr. Torez 44, St. Petersburg 194223, Russia.
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24
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Ständer S. How to define chronic pruritus: Symptom or disease? Exp Dermatol 2019; 28:1461-1465. [DOI: 10.1111/exd.13953] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 03/26/2019] [Accepted: 04/29/2019] [Indexed: 01/18/2023]
Affiliation(s)
- Sonja Ständer
- Department of Dermatology Center for Chronic Pruritus University Hospital Münster Münster Germany
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25
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Ständer S, Yosipovitch G. Substance P and neurokinin 1 receptor are new targets for the treatment of chronic pruritus. Br J Dermatol 2019; 181:932-938. [PMID: 31016733 DOI: 10.1111/bjd.18025] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/17/2019] [Indexed: 12/11/2022]
Abstract
BACKGROUND Chronic pruritus is a distressing symptom associated with various dermatological conditions and systemic diseases. Current treatment options are often inadequate, resulting in impaired quality of life for many patients. An understanding of the underlying mechanisms of itch across pruritic conditions is important for development of effective, targeted treatments for chronic pruritus. OBJECTIVES To provide an overview of the pathogenesis of chronic pruritus, focusing on the role of substance P (SP) and neurokinin 1 receptor (NK1 R) in itch signalling, and to describe data supporting NK1 R antagonism as a potential strategy for the treatment of chronic pruritus. METHODS A PubMed search was conducted to determine what data were available that investigated the role of SP and NK1 R in itch signalling. RESULTS SP is a neuropeptide that is a mediator of itch signalling. One of the target receptors for SP is NK1 R, which is expressed in the central nervous system and on multiple cell types involved in the initiation and transmission of itch. Studies demonstrating that SP and NK1 R are overexpressed across multiple chronic itch-inducing conditions and that NK1 R antagonism disrupts itch signalling and reduces itch provide a rationale for targeting this pathway as a potential treatment of chronic pruritus across multiple diseases. CONCLUSIONS A large and growing body of evidence, including recent phase II clinical studies of NK1 R antagonists, demonstrate that SP and NK1 R play an important role in itch signalling. Additional studies are ongoing to further evaluate the use of NK1 R antagonists for the treatment of chronic pruritus. What's already known about this topic? Chronic pruritus has a significant impact on quality of life. Current treatment options for chronic pruritus are inadequate. Substance P (SP) and neurokinin 1 receptor (NK1 R) have been shown to play a role in itch signalling, and may be a rational target for addressing chronic pruritus. NK1 R antagonists are being evaluated as potential treatment for chronic pruritus. What does this study add? This review provides a compilation of the most up-to-date data elucidating the role of SP and NK1 R in itch signalling, which supports targeting this pathway as a potential treatment of chronic pruritus. NK1 R antagonism disrupts itch signalling and reduces itch. A summary of the latest data on NK1 R antagonists in the treatment of pruritus is provided.
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Affiliation(s)
- S Ständer
- Center for Chronic Pruritus, Department of Dermatology, University Hospital Münster, Münster, Germany
| | - G Yosipovitch
- Miami Itch Center, Dr Phillip Frost Department of Dermatology and Cutaneous Surgery, Miller School of Medicine, University of Miami, Miami, FL, U.S.A
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Abstract
Neuropathic itch is a pathological condition that is due to damage within the nervous system. This type of itch can be severe and unrelenting, which has a very negative impact on quality of life. Neuropathic itch is more common than generally appreciated because most types of neuropathic pain have a neuropathic itch counterpart. Unfortunately, much like neuropathic pain, there is a lack of effective treatments for neuropathic itch. Here, we consider the neural basis of itch and then describe how injuries within these neural circuits can lead to neuropathic itch in both animal models and human disease states.
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27
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Barbiturates enhance itch-associated scratching in atopic dermatitis mice: A possible clue to understanding nocturnal pruritus in atopic dermatitis. Eur J Pharmacol 2018; 836:57-66. [PMID: 30125561 DOI: 10.1016/j.ejphar.2018.08.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 08/07/2018] [Accepted: 08/14/2018] [Indexed: 11/20/2022]
Abstract
In chronic pruritic diseases such as atopic dermatitis, pruritus is exacerbated during nocturnal sleep; however, the underlying mechanism remains unclear. We previously demonstrated that acute administration of the sedative-hypnotics ethanol markedly enhanced itch-associated spontaneous scratching in a diet-induced mouse model of atopic dermatitis. In the present study, to expand our previous finding and provide a general mechanism for the central modulation of chronic itch, we examined whether other hypnotic drugs, such as barbiturates and benzodiazepines, also enhance scratching, and further investigated the underlying mechanism. Barbiturates markedly enhanced spontaneous scratching in the atopic dermatitis model but not controls. However, unexpectedly, benzodiazepines only slightly increased scratching, and the selective γ-aminobutyric acid type A (GABAA) receptor agonist, muscimol, had no effect. Local injection studies have demonstrated that barbiturates act at the supraspinal level to enhance scratching. Barbiturate-induced scratching was inhibited not only by GABAA receptor antagonists but also by an L-type voltage-dependent calcium channel (L-VDCC) agonist and an α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptor agonist. An intracisternally injected AMPA receptor antagonist alone or in combination with an L-VDCC antagonist sufficiently enhanced scratching. Barbiturate-induced scratching enhancement was observed in another atopic dermatitis model, NC/Nga, but not in histamine-induced acute itch model in normal healthy mice. Overall, our results suggest that a synergistic effect among AMPA receptor inhibition, GABAA receptor activation, and L-VDCC inhibition in the brain mediates barbiturate-induced scratching in atopic dermatitis mice. This observation may provide a novel clue to understanding a supraspinal itch mechanism in chronic diseases such as atopic dermatitis.
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Huang K, Hu DD, Bai D, Wu ZY, Chen YY, Zhang YJ, Lv X, Wang QX, Zhang L. Persistent Extracellular Signal-Regulated Kinase Activation by the Histamine H4 Receptor in Spinal Neurons Underlies Chronic Itch. J Invest Dermatol 2018; 138:1843-1850. [DOI: 10.1016/j.jid.2018.02.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 02/11/2018] [Accepted: 02/14/2018] [Indexed: 01/17/2023]
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Carrion AF, Rosen JD, Levy C. Understanding and Treating Pruritus in Primary Biliary Cholangitis. Clin Liver Dis 2018; 22:517-532. [PMID: 30259850 DOI: 10.1016/j.cld.2018.03.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Pruritus is a common symptom with primary biliary cholangitis. Research has focused on refining understanding of the neurohumoral pathways involved in transduction of pruritus from peripheral cutaneous receptors to the central nervous system, and identifying modulating drugs. Current treatments have variable efficacy and safety. Because of the deleterious effects on quality of life or debilitation, many patients necessitate individualized therapeutic approaches; clinicians may need to consider invasive treatment options. This article highlights various therapeutic interventions, from general measures to invasive strategies, and novel agents under investigation, providing clinicians with the management tricks of the trade.
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Affiliation(s)
- Andres F Carrion
- Division of Gastroenterology and Hepatology, Texas Tech University Health Sciences Center, 4800 Alberta Avenue, El Paso, TX 79905, USA.
| | - Jordan D Rosen
- Department of Dermatology and Cutaneous Surgery, Miami Itch Center, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Cynthia Levy
- Division of Hepatology, Schiff Center for Liver Diseases, University of Miami Miller School of Medicine, Miami, FL, USA
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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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Jing PB, Cao DL, Li SS, Zhu M, Bai XQ, Wu XB, Gao YJ. Chemokine Receptor CXCR3 in the Spinal Cord Contributes to Chronic Itch in Mice. Neurosci Bull 2017; 34:54-63. [PMID: 28401489 DOI: 10.1007/s12264-017-0128-z] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 03/01/2017] [Indexed: 12/30/2022] Open
Abstract
Recent studies have shown that the chemokine receptor CXCR3 and its ligand CXCL10 in the dorsal root ganglion mediate itch in experimental allergic contact dermatitis (ACD). CXCR3 in the spinal cord also contributes to the maintenance of neuropathic pain. However, whether spinal CXCR3 is involved in acute or chronic itch remains unclear. Here, we report that Cxcr3 -/- mice showed normal scratching in acute itch models but reduced scratching in chronic itch models of dry skin and ACD. In contrast, both formalin-induced acute pain and complete Freund's adjuvant-induced chronic inflammatory pain were reduced in Cxcr3 -/- mice. In addition, the expression of CXCR3 and CXCL10 was increased in the spinal cord in the dry skin model induced by acetone and diethyl ether followed by water (AEW). Intrathecal injection of a CXCR3 antagonist alleviated AEW-induced itch. Furthermore, touch-elicited itch (alloknesis) after compound 48/80 or AEW treatment was suppressed in Cxcr3 -/- mice. Finally, AEW-induced astrocyte activation was inhibited in Cxcr3 -/- mice. Taken together, these data suggest that spinal CXCR3 mediates chronic itch and alloknesis, and targeting CXCR3 may provide effective treatment for chronic pruritus.
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Affiliation(s)
- Peng-Bo Jing
- Pain Research Laboratory, Institute of Nautical Medicine, Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, 226019, China
| | - De-Li Cao
- Pain Research Laboratory, Institute of Nautical Medicine, Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, 226019, China
| | - Si-Si Li
- Pain Research Laboratory, Institute of Nautical Medicine, Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, 226019, China
| | - Meixuan Zhu
- Pain Research Laboratory, Institute of Nautical Medicine, Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, 226019, China
| | - Xue-Qiang Bai
- Pain Research Laboratory, Institute of Nautical Medicine, Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, 226019, China
| | - Xiao-Bo Wu
- Pain Research Laboratory, Institute of Nautical Medicine, Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, 226019, China
| | - Yong-Jing Gao
- Pain Research Laboratory, Institute of Nautical Medicine, Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, 226019, China. .,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China.
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