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Lu XY, Teng JF, Yao J, Li X, Wu B, Hu XQ, Wang P, Jiang XQ, Sui JF, Hu KH, Xu YM, Liu SL. The projection from the prelimbic cortex to the ventral tegmental area negatively regulates 5-HT-induced itch-scratching and positively regulates itch-related aversion in rats. Brain Res Bull 2025; 223:111283. [PMID: 40024398 DOI: 10.1016/j.brainresbull.2025.111283] [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: 11/15/2024] [Revised: 02/18/2025] [Accepted: 02/27/2025] [Indexed: 03/04/2025]
Abstract
Direct and indirect evidence suggests that the prelimbic cortex (PrL) and the ventral tegmental area (VTA) are the key brain regions involved in the regulation of itch sensation and itch-related emotions. The PrL projects widely to various cortical and subcortical brain regions, with the VTA being one of the main targets of PrL descending projections. However, the differential roles of the PrL-VTA pathway in the regulation of itch sensation and itch-related emotion remain unclear. In this study, we investigated 5-HT-induced conditioned place aversion (CPA) and itch-scratching behavior in rats after pharmacogenetic inhibition of PrL-VTA projection activity. Pharmacogenetic inhibition of a subpopulation of PrL glutamatergic neurons projecting to the VTA increased 5-HT-induced itch-scratching behavior but alleviated the conditioned place aversion behavior accompanying acute itch, indicating that the descending pathway from the PrL to the VTA negatively controls itch sensation but positively regulates itch-related negative emotion. GABAergic and DAergic neurons in the VTA are potentially responsible for mediating the opposite regulatory effects of PrL-VTA projections on itch sensation and emotion, respectively. These results are helpful for further understanding the neuroregulatory mechanisms of different components of itch.
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Affiliation(s)
- Xing-Yu Lu
- Department of Dermatology of Jiangbei Campus, The First Affiliated Hospital of Army Medical University, Chongqing 400020, China
| | - Jun-Fei Teng
- Department of Dermatology of Jiangbei Campus, The First Affiliated Hospital of Army Medical University, Chongqing 400020, China
| | - Juan Yao
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
| | - Xuan Li
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
| | - Bing Wu
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
| | - Xue-Qiang Hu
- Department of Dermatology of Jiangbei Campus, The First Affiliated Hospital of Army Medical University, Chongqing 400020, China
| | - Ping Wang
- Department of Dermatology of Jiangbei Campus, The First Affiliated Hospital of Army Medical University, Chongqing 400020, China
| | - Xiao-Qian Jiang
- Rehabilitation Center of Suining Central Hospital, Suining, Sichuan 629000, China
| | - Jian-Feng Sui
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China; Rehabilitation Center of Suining Central Hospital, Suining, Sichuan 629000, China
| | - Ke-Hui Hu
- Rehabilitation Center of Suining Central Hospital, Suining, Sichuan 629000, China.
| | - Yue-Ming Xu
- Department of Anesthesiology of Jiangbei Campus, The First Affiliated Hospital of Army Medical University, Chongqing 400020, China.
| | - Shu-Lei Liu
- Department of Dermatology of Jiangbei Campus, The First Affiliated Hospital of Army Medical University, Chongqing 400020, China.
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Teng JF, Lu XY, Long JH, Shi Y, Hu XQ, Sui JF, Wang P, Zeng LL, Li X, Xu JH, Ou ZZ, Hu KH, Liu SL. The projection from the rostral anterior cingulate cortex to the ventral tegmental area regulates 5-HT-induced itch aversion and scratching in rats. Neurobiol Dis 2025; 207:106844. [PMID: 39956463 DOI: 10.1016/j.nbd.2025.106844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2024] [Revised: 02/10/2025] [Accepted: 02/13/2025] [Indexed: 02/18/2025] Open
Abstract
Many studies in humans and rodents have shown that the anterior cingulate cortex (ACC) plays a critical role in the regulation of pain-related aversion and that the projection from the rostral ACC (rACC) to the ventral tegmental area (VTA) is implicated in this modulation process. The ACC is also reported to be involved in the regulation of itch-scratch behavior. However, it remains unclear whether the ACC is involved in the modulation of the negative emotions induced by acute itch sensation. In this study, we investigated the pruritogen-induced conditioned place aversion (CPA) and itch-scratching behavior in rats after pharmacogenetic inhibition of the activities of rACC-VTA pathway or the rACC neurons, respectively. Pharmacogenetic inhibition of glutamatergic neurons of rACC projecting to the VTA alleviated the CPA responses and itch-scratching behavior induced by the subcutaneous injection of 5-HT, a nonhistamine-dependent pruritogen. However, pharmacogenetic inhibition of rACC neurons did not change the CPA behavior associated with itch and, conversely, increased itch-scratching behavior. These results reveal that a specific subpopulation of rACC neurons projecting to the VTA positively regulates itch sensation and the negative emotion accompanying itch, whereas the global rACC negatively modulates acute non-histaminergic itch in rats. Postsynaptic GABAergic neurons in the VTA may mediate emotion modulation of the rACC-VTA pathway. The current findings contribute to a better understanding of the circuit mechanisms underlying the processing of different components of itch, such as sensation and emotion.
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Affiliation(s)
- Jun-Fei Teng
- Department of Dermatology of Jiangbei Campus, The First Affiliated Hospital of Army Medical University, Chongqing 400020, China
| | - Xing-Yu Lu
- Department of Dermatology of Jiangbei Campus, The First Affiliated Hospital of Army Medical University, Chongqing 400020, China
| | - Jun-Hui Long
- Department of Dermatology of Jiangbei Campus, The First Affiliated Hospital of Army Medical University, Chongqing 400020, China
| | - Ying Shi
- Department of Rheumatology, The Ninth People's Hospital of Chongqing, Chongqing 400799, China
| | - Xue-Qiang Hu
- Department of Dermatology of Jiangbei Campus, The First Affiliated Hospital of Army Medical University, Chongqing 400020, China
| | - Jian-Feng Sui
- Department of Rehabilitation Medicine, SuiNing Central Hospital, SuiNing 629000, China; Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
| | - Ping Wang
- Department of Dermatology of Jiangbei Campus, The First Affiliated Hospital of Army Medical University, Chongqing 400020, China
| | - Lian-Lin Zeng
- Department of Rehabilitation Medicine, SuiNing Central Hospital, SuiNing 629000, China
| | - Xuan Li
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
| | - Jin-He Xu
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
| | - Zu-Zhen Ou
- Department of Dermatology of Jiangbei Campus, The First Affiliated Hospital of Army Medical University, Chongqing 400020, China
| | - Ke-Hui Hu
- Department of Rehabilitation Medicine, SuiNing Central Hospital, SuiNing 629000, China.
| | - Shu-Lei Liu
- Department of Dermatology of Jiangbei Campus, The First Affiliated Hospital of Army Medical University, Chongqing 400020, China.
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Li CY, Chang WC, Chen MH, Tu PC, Chen TL, Chen CC, Chang YT, Chen YY, Bai YM. Correlation of Disease Severity, Proinflammatory Cytokines, and Reduced Brain Gray Matter Volumes in Patients with Atopic Dermatitis. Dermatitis 2024; 35:489-497. [PMID: 38634841 DOI: 10.1089/derm.2023.0340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2024]
Abstract
Background: Atopic dermatitis (AD) is a chronic inflammatory skin disease. However, few studies have investigated brain changes associated with chronic inflammation. We hypothesized that chronic inflammation might be related to brain structural alterations in patients with AD. Objectives: To investigate the association between disease severity (Eczema Area and Severity Index [EASI]), proinflammatory cytokines, and differences in brain gray matter (GM) volume in patients with AD. Methods: Nineteen patients with AD and 19 age- and sex-matched healthy subjects were enrolled. All participants underwent clinical assessment and brain magnetic resonance imaging. Voxel-based morphometry was performed to analyze GM volume differences. Results: Patients with AD exhibited significantly decreased GM volume in many brain regions, such as bilateral precentral gyrus, right frontal pole, and right middle temporal gyrus (P < 0.001), compared with healthy subjects. Notably, in patients with AD, the GM volume in right middle temporal gyrus was negatively associated with both EASI score and proinflammatory cytokines (sIL-2R [soluble interleukin 2 receptor] and TNF-α receptor-1), whereas the GM volume in left precentral gyrus was negatively associated with both EASI score and proinflammatory cytokines (sIL-2R and CRP). Conclusion: Patients with AD demonstrated significant brain GM volume reduction in many brain regions, which is related to disease severity and proinflammatory cytokines.
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Affiliation(s)
- Cheng-Yuan Li
- From the Department of Dermatology, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Dermatology, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Wan-Chen Chang
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Psychiatry, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Mu-Hong Chen
- Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Psychiatry, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Pei-Chi Tu
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan
- Institute of Philosophy of Mind and Cognition, National Yang-Ming University, Taipei, Taiwan
| | - Tai-Li Chen
- From the Department of Dermatology, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Dermatology, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Chih-Chiang Chen
- From the Department of Dermatology, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Dermatology, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Institute of Clinical Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Yun-Ting Chang
- From the Department of Dermatology, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Dermatology, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - You-Yin Chen
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
- The Ph.D. Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Ya-Mei Bai
- Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Psychiatry, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
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Hadad R, Mandelli ML, Rankin KP, Toohey C, Sturm VE, Javandel S, Milicic A, Knudtson M, Allen IE, Hoffmann N, Friedberg A, Possin K, Valcour V, Miller BL. Itching Frequency and Neuroanatomic Correlates in Frontotemporal Lobar Degeneration. JAMA Neurol 2024; 81:977-984. [PMID: 39037825 PMCID: PMC11264090 DOI: 10.1001/jamaneurol.2024.2213] [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: 01/07/2024] [Accepted: 05/24/2024] [Indexed: 07/24/2024]
Abstract
Importance Itching is common in geriatric populations and is frequently linked to dermatological or systemic conditions. Itching engages specific brain regions that are implicated in the pathogenesis of frontotemporal lobar degeneration spectrum disorders (FTLD-SD). Thus, itching of undetermined origin (IUO) may indicate the presence of a neurodegenerative process. Objective To compare the frequency of itching in FTLD-SD and Alzheimer disease (AD) and to determine the neuroanatomical underpinnings of IUO. Design, Setting, and Participants This case-control study evaluated data and brain magnetic resonance images (MRIs) for participants with FTLD-SD or AD. Participants of a research study on FTLD-SD at the University of California, San Francisco, Memory and Aging Center were evaluated from May 1, 2002, to December 31, 2021. The exposure group underwent structural brain MRI within 6 months of initial diagnosis. Research visit summaries were reviewed to validate qualitative details and accurately identify itching with undetermined origin (IUO). Exposures Symptoms suggestive of FTLD-SD or AD. Main Outcomes and Measures Frequency of itching in FTLD-SD and AD and neuroanatomic correlates. Results A total of 2091 research visit summaries were reviewed for 1112 patients exhibiting symptoms indicative of FTLD-SD or AD. From 795 records where itching or a related phrase was endorsed, 137 had IUO. A total of 454 participants were included in the study: 137 in the itching group (mean [SD] age, 62.7 [9.9] years; 74 [54%] females and 63 males [46%]) and 317 in the nonitching group (mean [SD] age, 60.7 [10.8] years; 154 [49%] females and 163 males [51%]). Groups were similar in age, sex, and disease severity. More frequent itching was found in FTLD-SD (95/248 patients [38%], of which 44 [46%] had behavioral variant frontotemporal dementia [bvFTD]) compared with the AD group (14/77 patients [18%]; P = .001). The odds of itching were 2.4 (95% CI, 1.48-3.97) times higher for FTLD-SD compared with all other cases of dementia. Compared with healthy controls, the group with IUO exhibited greater gray matter atrophy bilaterally in the amygdala, insula, precentral gyrus, and cingulum, as well as in the right frontal superior gyrus and thalamus. Among patients with bvFTD and itching vs bvFTD without itching, itching was associated with right-lateralized gray matter atrophy affecting the insula, thalamus, superior frontal gyrus, and cingulum. Conclusions and Relevance Among individuals with IUO, FTLD-SD was disproportionately represented compared with AD. In FTLD-SD, dysfunction in the right anterior insula and its connected regions, including the right precentral gyrus, cingulum, and bilateral amygdala, contribute to dysregulation of the itching-scratching networks, resulting in uncontrollable itching or skin picking. Awareness among physicians about the relationship between neurodegeneration and itching may help in the management of itch in older individuals. Further studies are needed to determine the best treatments for these symptoms in patients with neurodegenerative disorders.
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Affiliation(s)
- Rafi Hadad
- Stroke and Cognition Institute, Department of Neurology, Rambam Health Care Campus, Haifa, Israel
- Global Brain Health Institute, Department of Neurology, University of California, San Francisco
| | - Maria Luisa Mandelli
- Global Brain Health Institute, Department of Neurology, University of California, San Francisco
- Memory and Aging Center, Department of Neurology, University of California, San Francisco
| | - Katherine P. Rankin
- Global Brain Health Institute, Department of Neurology, University of California, San Francisco
- Memory and Aging Center, Department of Neurology, University of California, San Francisco
| | - Charlie Toohey
- Memory and Aging Center, Department of Neurology, University of California, San Francisco
| | - Virginia E. Sturm
- Global Brain Health Institute, Department of Neurology, University of California, San Francisco
- Memory and Aging Center, Department of Neurology, University of California, San Francisco
- Department of Psychiatry and Behavioral Sciences University of California, San Francisco
| | - Shireen Javandel
- Global Brain Health Institute, Department of Neurology, University of California, San Francisco
- Memory and Aging Center, Department of Neurology, University of California, San Francisco
| | - Andjelika Milicic
- Global Brain Health Institute, Department of Neurology, University of California, San Francisco
- Memory and Aging Center, Department of Neurology, University of California, San Francisco
| | - Marguerite Knudtson
- Memory and Aging Center, Department of Neurology, University of California, San Francisco
| | - Isabel Elaine Allen
- Global Brain Health Institute, Department of Neurology, University of California, San Francisco
- Department of Epidemiology and Biostatistics, University of California, San Francisco
| | - Nathalia Hoffmann
- Federal University of Health Sciences of Porto Alegre (UFCSPA), Porto Alegre, Brazil
| | - Adit Friedberg
- Global Brain Health Institute, Department of Neurology, University of California, San Francisco
- Memory and Aging Center, Department of Neurology, University of California, San Francisco
| | - Katherine Possin
- Global Brain Health Institute, Department of Neurology, University of California, San Francisco
- Memory and Aging Center, Department of Neurology, University of California, San Francisco
| | - Victor Valcour
- Global Brain Health Institute, Department of Neurology, University of California, San Francisco
- Memory and Aging Center, Department of Neurology, University of California, San Francisco
| | - Bruce L. Miller
- Global Brain Health Institute, Department of Neurology, University of California, San Francisco
- Memory and Aging Center, Department of Neurology, University of California, San Francisco
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Wu H, Dai W, Hong Z, Qin Y, Yang M, Wang B, Liao J. Higher-order sensorimotor circuit of the whole-brain functional network involved in pruritus regulation in atopic dermatitis. J Eur Acad Dermatol Venereol 2024; 38:873-882. [PMID: 38069553 DOI: 10.1111/jdv.19691] [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: 05/22/2023] [Accepted: 11/09/2023] [Indexed: 04/26/2024]
Abstract
BACKGROUND Little is known about the neural mechanisms underlying pruritus regulation in Atopic dermatitis (AD). OBJECTIVE To investigate the functional changes of the resting-state whole brain network of AD participants and the mechanisms by which they were involved in pruritus regulation. METHOD Based on the functional magnetic resonance imaging data from 19 AD participants and 37 healthy controls (HC), a graph-theoretical measure of degree centrality (DC) conjoined with a voxel-level seed-based functional connectivity (FC) method was used to identify abnormal higher-order nodes and the functionally relevant circuit in AD participants compared to healthy controls (HC). RESULTS Of 64 participants screened, 19 AD participants (12M/7F, median [IQR] age, 27 [14] years) and 36 HCs (13M/23F, median [IQR] age, 20 [1] years) were enrolled. DC values of the left superior frontal gyrus (LSFG) increased in AD participants and exhibited a negative correlation with the SCORAD score (r = -0.561, p = 0.012) compared with HC. In the FC analysis with LSFG as the seed, FC values of several sensory and motor regions increased in AD participants, highly overlapping with the anatomical distribution of the inferior fronto-occipital fascicle (IFOF). AD participants with severe pruritus exhibited lower levels of DC (T = -2.316, p = 0.033) and FC between the LSFG and left insula (T = -2.203, p = 0.042) than those with mild-to- moderate pruritus. CONCLUSIONS AND RELEVANCE LSFG was involved in pruritus regulation in AD by forming a high-order sensorimotor circuit through the IFOF, a white matter fascicle that proved to provide multimodal integration in motor control and sensory information processing. These results offer more mechanism-guided treatment targets for severe pruritus in AD.
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Affiliation(s)
- Haishan Wu
- National Clinical Research Center for Mental Disorders, Department of Psychiatry, China National Technology Institute on Mental Disorders, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Wenyu Dai
- National Clinical Research Center for Mental Disorders, Department of Psychiatry, China National Technology Institute on Mental Disorders, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Zhaoyi Hong
- Department of Dermatology, Second Xiangya Hospital, Hunan Key Laboratory of Medical Epigenomics, Central South University, Changsha, Hunan, China
| | - Yue Qin
- National Clinical Research Center for Mental Disorders, Department of Psychiatry, China National Technology Institute on Mental Disorders, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Min Yang
- National Clinical Research Center for Mental Disorders, Department of Psychiatry, China National Technology Institute on Mental Disorders, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Bolun Wang
- Scientific Research Program of Hunan Provincial Health Commission, Department of Radiology, Clinical Research Center for Medical Imaging in Hunan Province, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Jieyue Liao
- Department of Dermatology, Second Xiangya Hospital, Hunan Key Laboratory of Medical Epigenomics, Central South University, Changsha, Hunan, China
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Biazus Soares G, Hashimoto T, Yosipovitch G. Atopic Dermatitis Itch: Scratching for an Explanation. J Invest Dermatol 2024; 144:978-988. [PMID: 38363270 DOI: 10.1016/j.jid.2023.10.048] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 10/20/2023] [Accepted: 10/31/2023] [Indexed: 02/17/2024]
Abstract
Chronic pruritus is a cardinal symptom of atopic dermatitis (AD). The mechanisms underlying atopic itch involve intricate crosstalk among skin, immune components, and neural components. In this review, we explore these mechanisms, focusing on key players and interactions that induce and exacerbate itch. We discuss the similarities and differences between pruritus and pain in patients with AD as well as the relationship between pruritus and factors such as sweat and the skin microbiome. Furthermore, we explore novel targets that could provide significant itch relief in these patients as well as exciting future research directions to better understand atopic pruritus in darker skin types.
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Affiliation(s)
- Georgia Biazus Soares
- Miami Itch Center, Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Takashi Hashimoto
- Department of Dermatology, National Defense Medical College, Tokorozawa, Japan
| | - Gil Yosipovitch
- Miami Itch Center, Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, Florida, USA.
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Mahmoud O, Oladipo O, Mahmoud RH, Yosipovitch G. Itch: from the skin to the brain - peripheral and central neural sensitization in chronic itch. Front Mol Neurosci 2023; 16:1272230. [PMID: 37849619 PMCID: PMC10577434 DOI: 10.3389/fnmol.2023.1272230] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 09/05/2023] [Indexed: 10/19/2023] Open
Abstract
Similar to chronic pain, chronic itch is frequently linked to neural sensitization, a phenomenon wherein the nervous system becomes hypersensitive to stimuli. This process of neural sensitization of chronic itch is orchestrated by various signaling pathways and mediators in both the peripheral and central nervous systems. At the level of the peripheral nervous system, inflammation and neuroimmune interactions induce plastic changes to peripheral nerve fibers, thereby amplifying the transmission of itch signaling. Neural sensitization in the central nervous system occurs at both the spinal cord and brain levels. At the level of the spinal cord, it involves hyperactivity of itch-activating spinal pathways, dysfunction of spinal inhibitory circuits, and attenuation of descending supraspinal inhibitory pathways. In the brain, neural sensitization manifests as structural and functional changes to itch-associated brain areas and networks. Currently, we have a diverse array of neuroimmune-modulating therapies targeting itch neural sensitization mechanisms to help with providing relief to patients with chronic itch. Itch research is a dynamic and continually evolving field, and as we grow in our understanding of chronic itch mechanisms, so will our therapeutic toolbox. Further studies exploring the peripheral and central neural sensitization mechanisms in the context of chronic itch are needed.
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Affiliation(s)
| | | | | | - Gil Yosipovitch
- Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, Miami Itch Center, University of Miami Miller School of Medicine, Miami, FL, United States
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Liu JJ, Li X, Guo J, Yu S, Yang S. Role of GRPR in Acupuncture Intervention in the "Itch-scratch Vicious Cycle" Spinal Circuit of Chronic Pruritus. Chin Med 2023; 18:2. [PMID: 36597164 PMCID: PMC9809006 DOI: 10.1186/s13020-022-00706-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 12/28/2022] [Indexed: 01/04/2023] Open
Abstract
Many previous studies have shown the potential antipruritic effect of acupuncture. This paper reviews the antipruritic mechanisms of acupuncture according to these aspects: sample characteristics, detail of intervention, and effects evaluation. The majority of research on acupuncture's antipruritic effect has focused on primary afferents of the peripheral mechanism. Relatively few studies, however, have addressed the central mechanisms. Combination the latest research achievements of chronic itch, gastrin-releasing peptide receptor (GRPR) in the dorsal horn of the spinal cord may represent the first molecule identified that is dedicated to mediating the itch response and may provide an important therapeutic target for the treatment of chronic pruritic conditions. Therefore, GRPR may be a new target for acupuncture to relieve itch in the future and provide new ideas for acupuncture intervention in the mechanisms of the spinal level of the "itch-scratch vicious cycle" of chronic itch.
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Affiliation(s)
- Jia-jia Liu
- grid.411304.30000 0001 0376 205XAcupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan China
| | - Xuemei Li
- grid.411304.30000 0001 0376 205XAcupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan China
| | - Jing Guo
- grid.411304.30000 0001 0376 205XAcupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan China
| | - Shuguang Yu
- grid.411304.30000 0001 0376 205XAcupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan China ,Key Laboratory of Sichuan Province for Acupuncture and Chronobiology, Chengdu, Sichuan China
| | - Sha Yang
- grid.411304.30000 0001 0376 205XAcupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan China ,grid.411304.30000 0001 0376 205XAcupuncture and Brain Science Research Center, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan China
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Zhang L, Zou Z, Yu S, Xiao X, Shi Y, Cao W, Liu Y, Zheng H, Zheng Q, Zhou S, Yao J, Deng Y, Yang Q, Chen S, Hao P, Li N, Li Y. Functional connectivity impairment of thalamus-cerebellum-scratching neural circuits in pruritus of chronic spontaneous urticaria. Front Neurosci 2022; 16:1026200. [PMID: 36340791 PMCID: PMC9630740 DOI: 10.3389/fnins.2022.1026200] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 10/06/2022] [Indexed: 11/18/2022] Open
Abstract
Pruritus of chronic spontaneous urticaria (CSU) is one of the most common and irritating sensations that severely affects the quality of life. However, the changes in the functional connectivity (FC) between thalamic subregions and other brain regions have not been fully elucidated. This study aimed to explore the potential changes in brain neural circuits by focusing on various subregions of the thalamus in patients with CSU pruritus to contribute to the understanding of chronic pruritus from the perspective of central mechanisms. A total of 56 patients with CSU and 30 healthy controls (HCs) completed the data analysis. Urticaria Activity Score 7 (UAS7), pruritus visual analog score (VAS-P), Dermatological Life Quality Index (DLQI), and immunoglobulin E (IgE) values were collected to assess clinical symptoms. Seed-based resting-state functional connectivity (rs-FC) analysis was used to assess relevant changes in the neural circuits of the brain. Compared to HCs, seeds within the caudal temporal thalamus (cTtha) on the right side of patients with CSU showed increased rs-FC with the cerebellum anterior lobe (CAL). Seeds within the lateral prefrontal thalamus (lPFtha) on the right side showed increased rs-FC with both CAL and pons, while those within the medial prefrontal thalamus (mPFtha) on the right side showed increased rs-FC with both CAL and the dorsal lateral prefrontal cortex (dlPFC) on the right side. Seeds within the posterior parietal thalamus (PPtha) on the right side showed increased rs-FC with the cerebellum posterior lobe (CPL) on the left side. The UAS7 values and IgE levels were positively correlated with the rs-FC of the right dlPFC. Our results suggest that patients with CSU may exhibit stronger rs-FC alterations between certain thalamic subregions and other brain regions. These changes affect areas of the brain involved in sensorimotor and scratching. Trial registration number [http://www.chictr.org.cn], identifier [ChiCTR1900022994].
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Affiliation(s)
- Leixiao Zhang
- Department of Integrated Traditional and Western Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Zihao Zou
- Acupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Siyi Yu
- Acupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Xianjun Xiao
- College of Health Rehabilitation, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Yunzhou Shi
- Acupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Wei Cao
- Acupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Ying Liu
- Chinese Medicine Hospital, Chengdu, Sichuan, China
| | - Hui Zheng
- Acupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Qianhua Zheng
- Acupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Siyuan Zhou
- Acupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Junpeng Yao
- Acupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Yanli Deng
- Sichuan Second Chinese Medicine Hospital, Chengdu, Sichuan, China
| | - Qian Yang
- Acupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Sijue Chen
- Acupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Pingsheng Hao
- Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Ning Li
- Department of Integrated Traditional and Western Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Ying Li
- Acupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
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10
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Dehghan Nayyeri M, Missler M, Ritterbach R, Sundermann B, Wulms N, Süer A, Dugas M, Pereira MP, Ständer S, Schmelz M, Pfleiderer B. Altered resting-state functional connectivity of default mode network in brachioradial pruritus. J Eur Acad Dermatol Venereol 2022; 36:2214-2223. [PMID: 35796634 DOI: 10.1111/jdv.18411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 06/15/2022] [Indexed: 11/29/2022]
Abstract
BACKGROUND Patients with chronic pruritus (CP) have a low quality of life, thus it is important to gain a better understanding of the underlying processes. Previous functional magnetic resonance imaging studies at rest (rs-fMRI) have shown that mainly areas associated with the default mode network (DMN), sensorimotor (SMN), frontoparietal (FPN) and salience networks (SN) are involved in the processing of itch in patients with chronic pruritus (CP), as well as the cortico-striatal circuit, which is involved in the motoric preparation of scratching. rs-fMRI studies on functional connectivity (FC) patterns of resting-state networks (RSNs) in patients with inflammatory atopic dermatitis (AD) or with neuropathic brachioradial pruritus (BRP) compared to healthy controls (HC) are lacking. OBJECTIVES The main goals of this study were to investigate whether functional connectivity within networks and areas associated with itch detection and processing are altered in patients with AD and BRP compared to matched healthy controls by rsfMRI, respectively. METHODS Patients with AD (n = 28) and with BRP (n = 28) were compared to corresponding matched healthy controls by rsfMRI. Group specific RSNs were identified by independent component analysis (ICA) and between-group differences in the RSNs were analyzed by dual regression technique. Seed-based functional connectivity was analyzed in several itch-related brain regions belonging to the DMN, SN and FPN, respectively. RESULTS ICA and seed-based analyses revealed decreased functional connectivity in BRP compared to HC specially within the DMN including the precuneus and cingulate cortex. For AD patients in comparison to HC, as well as when BRP and AD patients when compared directly, no significant FC differences at rest were seen. CONCLUSIONS Our findings point towards decreased FC particularly in the DMN at rest in patients with BRP. These results seem to indicate that central connectivity patterns at rest differentially encode itch in BRP and AD.
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Affiliation(s)
- Mahboobeh Dehghan Nayyeri
- Clinic of Radiology, University Hospital Muenster, Medical Faculty, University of Muenster, Muenster, Germany.,Department of Psychosomatic Medicine and Psychotherapy, LVR Clinic, Medical Faculty of the Heinrich-Heine-University Duesseldorf, Duesseldorf, Germany
| | - Miriam Missler
- Clinic of Radiology, University Hospital Muenster, Medical Faculty, University of Muenster, Muenster, Germany
| | - Rebecca Ritterbach
- Clinic of Radiology, University Hospital Muenster, Medical Faculty, University of Muenster, Muenster, Germany
| | - Benedikt Sundermann
- Institute of Radiology and Neuroradiology, Evangelisches Krankenhaus, Medical Campus, University of Oldenburg, Oldenburg, Germany.,Research Center Neurosensory Science, University of Oldenburg, Oldenburg, Germany
| | - Niklas Wulms
- Institute of Epidemiology and Social Medicine, University of Muenster, Muenster, Germany
| | - Aysenur Süer
- Institute of Medical Informatics, University of Muenster, Muenster, Germany
| | - Martin Dugas
- Institute of Medical Informatics, University Hospital Heidelberg, Heidelberg, Germany
| | - Manuel P Pereira
- Center for Chronic Pruritus, Department of Dermatology, University Hospital Muenster, Germany
| | - Sonja Ständer
- Center for Chronic Pruritus, Department of Dermatology, University Hospital Muenster, Germany
| | - Martin Schmelz
- Department of Experimental Pain Research, MCTN, Medical Faculty Mannheim, Heidelberg of University, Mannheim, Germany
| | - Bettina Pfleiderer
- Clinic of Radiology, University Hospital Muenster, Medical Faculty, University of Muenster, Muenster, Germany.,Otto Creutzfeld Center for Cognitive and Behavioral Neuroscience, Muenster, Germany
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11
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Tang Y, Cheng S, Wang J, Jin Y, Yang H, Lin Q, Xu S, Hui L, Yin Q, Yang Y, Wu X. Acupuncture for the Treatment of Itch: Peripheral and Central Mechanisms. Front Neurosci 2022; 15:786892. [PMID: 35431769 PMCID: PMC9005788 DOI: 10.3389/fnins.2021.786892] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/13/2021] [Indexed: 11/21/2022] Open
Abstract
Despite the widespread clinical use of acupuncture in the treatment of pruritus caused by psoriasis, urticaria, uremic, and other diseases, insights into the mechanism of action of acupuncture are still emerging. For the above reasons, a beneficial effect of acupuncture on pruritus was not recommended or reported in recent clinical practice guidelines. Acupuncture is a kind of physical stimulation, which has the characteristics of multi-channel and multi-target effects. The biomechanical stimulation signal of acupuncture needling can be transformed into bioelectric and chemical signals; interfere with kinds of cells and nerve fibers in the skin and muscle; alter signaling pathways and transcriptional activity of cells, mediators, and receptors; and result in inhibition of peripheral and central transmission of pruritus. Available mechanistic data give insights into the biological regulation potency of acupuncture for pruritus and provide a basis for more in-depth and comprehensive mechanism research.
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12
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Novak N. Dem Juckreiz auf den Fersen. J Dtsch Dermatol Ges 2022; 20:133-135. [PMID: 35146886 DOI: 10.1111/ddg.14735_g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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13
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Mu D, Sun YG. Circuit Mechanisms of Itch in the Brain. J Invest Dermatol 2021; 142:23-30. [PMID: 34662562 DOI: 10.1016/j.jid.2021.09.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/21/2021] [Accepted: 09/21/2021] [Indexed: 12/12/2022]
Abstract
Itch is an unpleasant somatic sensation with the desire to scratch, and it consists of sensory, affective, and motivational components. Acute itch serves as a critical protective mechanism because an itch-evoked scratching response will help to remove harmful substances invading the skin. Recently, exciting progress has been made in deciphering the mechanisms of itch at both the peripheral nervous system and the CNS levels. Key neuronal subtypes and circuits have been revealed for ascending transmission and the descending modulation of itch. In this review, we mainly summarize the current understanding of the central circuit mechanisms of itch in the brain.
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Affiliation(s)
- Di Mu
- Department of Anesthesiology, Shanghai General Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yan-Gang Sun
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology (CEBSIT), Chinese Academy of Sciences, Shanghai, China; Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai, China.
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14
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Lee IS, Kim K, Park HJ, Lee H, Jung WM, Kim DW, Chae Y. Neural Oscillation Associated with Contagious Itch in Patients with Atopic Dermatitis. Brain Sci 2021; 11:brainsci11040438. [PMID: 33805350 PMCID: PMC8067125 DOI: 10.3390/brainsci11040438] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 03/25/2021] [Accepted: 03/26/2021] [Indexed: 11/16/2022] Open
Abstract
Objective: Itch is an unpleasant sensation associated with an urge to scratch and is a major health care issue associated with atopic dermatitis (AD). Contagious itch, i.e., subjective feelings of itchiness induced by watching others’ scratching behavior, is common in patients with AD. Using electroencephalography, we examined alpha (8–13 Hz) oscillations in sensorimotor areas associated with the desire to scratch in patients with AD. Methods: Thirty-six patients with AD and 34 healthy controls (HCs) participated in this study. They evaluated their itch levels after watching short videos of a model scratching or tapping parts of his body. Neural oscillations were recorded from nine electrodes, including those placed over sensorimotor areas. Time–frequency analysis was used to compare mu rhythm suppression over the sensorimotor areas in response to these videos between patients with AD and HCs. Results: The behavioral test showed that the visual stimuli induced increased feelings of itchiness in patients with AD relative to HCs under the tapping and scratching conditions. The time–frequency analysis revealed that mu rhythm suppression in response to scratching images was significantly prominent in patients with AD, but not in HCs. Conclusion: Patients with AD exhibited increased susceptibility to contagious itch. This phenomenon might be related to enhanced mu rhythm suppression in sensorimotor areas of the brain in these patients. Our findings provide new insight into the neurophysiological basis of itch sensations in patients with AD.
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Affiliation(s)
- In-Seon Lee
- Acupuncture and Meridian Science Research Center, Kyung Hee University, Seoul 02447, Korea; (I.-S.L.); (H.-J.P.); (H.L.); (W.-M.J.)
| | - Kyuseok Kim
- Department of Ophthalmology, Otorhinolaryngology and Dermatology of Korean Medicine, College of Korean Medicine, Kyung Hee University, Seoul 02447, Korea;
| | - Hi-Joon Park
- Acupuncture and Meridian Science Research Center, Kyung Hee University, Seoul 02447, Korea; (I.-S.L.); (H.-J.P.); (H.L.); (W.-M.J.)
| | - Hyangsook Lee
- Acupuncture and Meridian Science Research Center, Kyung Hee University, Seoul 02447, Korea; (I.-S.L.); (H.-J.P.); (H.L.); (W.-M.J.)
| | - Won-Mo Jung
- Acupuncture and Meridian Science Research Center, Kyung Hee University, Seoul 02447, Korea; (I.-S.L.); (H.-J.P.); (H.L.); (W.-M.J.)
| | - Do-Won Kim
- Department of Biomedical Engineering, Chonnam National University, Yeosu 59626, Korea
- Correspondence: (D.-W.K.); (Y.C.)
| | - Younbyoung Chae
- Acupuncture and Meridian Science Research Center, Kyung Hee University, Seoul 02447, Korea; (I.-S.L.); (H.-J.P.); (H.L.); (W.-M.J.)
- Correspondence: (D.-W.K.); (Y.C.)
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15
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Najafi P, Misery L, Carré JL, Ben Salem D, Dufor O. Itch Matrixes. Front Med (Lausanne) 2021; 8:636904. [PMID: 33718409 PMCID: PMC7943862 DOI: 10.3389/fmed.2021.636904] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 01/25/2021] [Indexed: 11/13/2022] Open
Affiliation(s)
- Peyman Najafi
- Univ Brest, LIEN, Brest, France.,Paris-Saclay Institute of Neuroscience, Centre National de la Recherche Scientifique/Université Paris-Saclay, Gif-sur-Yvette, France
| | - Laurent Misery
- Univ Brest, LIEN, Brest, France.,University Hospital of Brest, Department of Dermatology, Brest, France
| | | | - Douraied Ben Salem
- Univ Brest, LATIM, INSERM UMR, Brest, France.,University Hospital of Brest, Department of Radiology, Brest, France
| | - Olivier Dufor
- Univ Brest, LIEN, Brest, France.,L@bISEN Yncréa Ouest, ISEN, Brest, France
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16
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Najafi P, Dufor O, Ben Salem D, Misery L, Carré JL. Itch processing in the brain. J Eur Acad Dermatol Venereol 2020; 35:1058-1066. [PMID: 33145804 DOI: 10.1111/jdv.17029] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 09/17/2020] [Accepted: 10/02/2020] [Indexed: 01/04/2023]
Abstract
Itch is a sensation defined as the urge to scratch. The central mechanisms of itch are being increasingly studied. These studies are usually based on experimental itch induction methods, which can be classified into the following categories: histamine-induced, induction by other non-histamine chemicals (e.g. cowhage), physically induced (e.g. electrical) and mentally induced (e.g. audio-visual). Because pain has been more extensively studied, some extrapolations to itch can be proposed and verified by experiments. Recent studies suggest that the itch-processing network in the brain could be disrupted in certain diseases. This disruption could be related to the implication of new regions or the exclusion of already engaged brain regions from itch-processing network in the brain.
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Affiliation(s)
| | - O Dufor
- LIEN, Univ Brest, Brest, France.,LabISEN Yncréa Ouest ISEN, Brest, France
| | - D Ben Salem
- Univ Brest, LaTIM, INSERM, UMR 1101, Brest, France.,University Hospital of Brest, Brest, France
| | - L Misery
- LIEN, Univ Brest, Brest, France.,University Hospital of Brest, Brest, France
| | - J-L Carré
- LIEN, Univ Brest, Brest, France.,University Hospital of Brest, Brest, France
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17
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Ramon M, Yakov S, Kuperman P, Granot M. The role of itch and pain modulation in the prediction of phototherapy outcomes: a prospective cohort study. J DERMATOL TREAT 2020; 33:1037-1041. [PMID: 32700633 DOI: 10.1080/09546634.2020.1800572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
OBJECTIVES Ability to predict which chronic itch patients will benefit from particular treatments is a challenge. Common features in itch and pain in respect to sensory elicitation, and mechanisms of processing including sensitization and inhibition at the peripheral and central levels, may serve to understand variability in treatment outcomes. As such this study aimed to explore whether phototherapy outcomes can be predicted by psychophysical parameters of pain and itch modulatory processing. METHODS Prospective cohort study on chronic-itch patients (n = 44) assessed before 20 treatments of NB UVB. Level of itch and pain reduction following painful stimulation (reflecting the 'pain inhibits pain' phenomenon) used to assess the top-down modulation response efficacy. Magnitude of Conditioned Pain Modulation (CPM) for itch (CPM-itch) and for pain (CPM-pain) (reflecting inhibition) and magnitude of temporal summation (TS) of pain (reflecting ascending facilitation pathways) assessed to predict treatment effect. RESULTS Higher improvement of itch symptoms following phototherapy was correlated with more efficient CPM-itch (r = 0.62, p < .001), but not magnitude of CPM-pain or level of temporal summation. DISCUSSION Findings emphasize the role of descending inhibition pathways in determining phototherapy efficacy in chronic itch patients. Such an evaluation-based approach may contribute to better patient selection for phototherapy improving patients' disease outcomes.
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Affiliation(s)
- Michal Ramon
- Department of Dermatology, Rambam Health Care Campus, Haifa, Israel
| | - Sarit Yakov
- Department of Dermatology, Rambam Health Care Campus, Haifa, Israel
| | - Pora Kuperman
- The Faculty of Social Welfare and Health Studies, University of Haifa, Haifa, Israel
| | - Michal Granot
- The Faculty of Social Welfare and Health Studies, University of Haifa, Haifa, Israel.,The Laboratory of Clinical Neurophysiology, the Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
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18
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Abstract
Itch, in particular chronic forms, has been widely recognized as an important clinical problem, but much less is known about the mechanisms of itch in comparison with other sensory modalities such as pain. Recently, considerable progress has been made in dissecting the circuit mechanisms of itch at both the spinal and supraspinal levels. Major components of the spinal neural circuit underlying both chemical and mechanical itch have now been identified, along with the circuits relaying ascending transmission and the descending modulation of itch. In this review, we summarize the progress in elucidating the neural circuit mechanism of itch at spinal and supraspinal levels.
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Affiliation(s)
- Xiao-Jun Chen
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, 320 Yue-Yang Road, 200031, Shanghai, China
- University of Chinese Academy of Sciences, 19A Yu-quan Road, 100049, Beijing, China
| | - Yan-Gang Sun
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, 320 Yue-Yang Road, 200031, Shanghai, China.
- Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, 201210, Shanghai, China.
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19
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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: 24] [Impact Index Per Article: 4.8] [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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20
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Najafi P, Carré JL, Ben Salem D, Brenaut E, Misery L, Dufor O. Central mechanisms of itch: A systematic literature review and meta-analysis. J Neuroradiol 2019; 47:450-457. [PMID: 31809769 DOI: 10.1016/j.neurad.2019.11.005] [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] [Received: 09/04/2019] [Revised: 11/18/2019] [Accepted: 11/25/2019] [Indexed: 12/11/2022]
Abstract
In recent years, studying the central mechanism of itch has gained momentum. However, a proper meta-analysis has not been conducted in this domain. In this study, we tried to respond to this need. A systematic search and a meta-analysis were carried out to estimate the central mechanism of itch. The itch matrix comprises the thalamus and the parietal, secondary somatosensory, insular and cingulate cortices. We have shown that the basal ganglia (BG) play an important role in itch reduction. Finally, we explored itch processing in AD patients and observed that the itch matrix in these patients was different. In conclusion, this is the first meta-analysis on the central mechanisms of itch perception and processing. Our study demonstrated that different modalities of itch induction can produce a common pattern of activity in the brain and provided further insights into understanding the underlying nature of itch central perception.
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Affiliation(s)
| | - Jean-Luc Carré
- LIEN, université Brest, 29200 Brest, France; University Hospital of Brest, 29200 Brest, France
| | - Douraied Ben Salem
- LaTIM, Inserm UMR 1101, université Brest, 29200 Brest, France; University Hospital of Brest, 29200 Brest, France
| | - Emilie Brenaut
- LIEN, université Brest, 29200 Brest, France; University Hospital of Brest, 29200 Brest, France
| | - Laurent Misery
- LIEN, université Brest, 29200 Brest, France; University Hospital of Brest, 29200 Brest, France.
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21
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Smith MP, Ly K, Thibodeaux Q, Weerasinghe T, Wu JJ, Yosipovitch G, Bhutani T, Liao W. Emerging Methods to Objectively Assess Pruritus in Atopic Dermatitis. Dermatol Ther (Heidelb) 2019; 9:407-420. [PMID: 31256388 PMCID: PMC6704205 DOI: 10.1007/s13555-019-0312-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Indexed: 12/31/2022] Open
Abstract
INTRODUCTION Atopic dermatitis (AD) is an inflammatory skin disease with a chronic, relapsing course. Clinical features of AD vary by age, duration, and severity but can include papules, vesicles, erythema, exudate, xerosis, scaling, and lichenification. However, the most defining and universal symptom of AD is pruritus. Pruritus or itch, defined as an unpleasant urge to scratch, is problematic for many reasons, particularly its negative impact on quality of life. Despite the profoundly negative impact of pruritus on patients with AD, clinicians and researchers lack standardized and validated methods to objectively measure pruritus. The purpose of this review is to discuss emerging methods to assess pruritus in AD by describing objective patient-centered tools developed or enhanced over the last decade that can be utilized by clinicians and researchers alike. METHODS This review is based on a literature search in Medline, Embase, and Web of Science databases. The search was performed in February 2019. The keywords were used "pruritus," "itch," "atopic dermatitis," "eczema," "measurements," "tools," "instruments," "accelerometer," "wrist actigraphy," "smartwatch," "transducer," "vibration," "brain mapping," "magnetic resonance imaging," and "positron emission tomography." Only articles written in English were included, and no restrictions were set on study type. To focus on emerging methods, prioritization was given to results from the last decade (2009-2019). RESULTS The search yielded 49 results in PubMed, 134 results in Embase, and 85 results in Web of Science. Each result was independently reviewed in a standardized manner by two of the authors (M.S., K.L.), and disagreements between reviewers were resolved by consensus. Relevant findings were categorized into the following sections: video surveillance, acoustic surveillance, wrist actigraphy, smart devices, vibration transducers, and neurological imaging. Examples are provided along with descriptions of how each technology works, instances of use in research or clinical practice, and as applicable, reports of validation studies and correlation with other methods. CONCLUSION The variety of new and improved methods to evaluate pruritus in AD is welcomed by clinicians, researchers, and patients alike. Future directions include next-generation smart devices as well as exploring new territories, such as identifying biomarkers that correlate to itch and machine-learning programs to identify itch processing in the brain. As these efforts continue, it will be essential to remain patient-centered by developing techniques that minimize discomfort, respect privacy, and provide accurate data that can be used to better manage itch in AD.
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Affiliation(s)
- Mary Patricia Smith
- Department of Dermatology, University of California, San Francisco, CA, USA.
| | - Karen Ly
- Department of Dermatology, University of California, San Francisco, CA, USA
| | - Quinn Thibodeaux
- Department of Dermatology, University of California, San Francisco, CA, USA
| | | | - Jashin J Wu
- Dermatology Research and Education Foundation, Irvine, CA, USA
| | - Gil Yosipovitch
- Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Tina Bhutani
- Department of Dermatology, University of California, San Francisco, CA, USA
| | - Wilson Liao
- Department of Dermatology, University of California, San Francisco, CA, USA
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Itch sensitization? A systematic review of studies using quantitative sensory testing in patients with chronic itch. Pain 2019; 160:2661-2678. [DOI: 10.1097/j.pain.0000000000001678] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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23
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Dong X, Dong X. Peripheral and Central Mechanisms of Itch. Neuron 2019; 98:482-494. [PMID: 29723501 DOI: 10.1016/j.neuron.2018.03.023] [Citation(s) in RCA: 253] [Impact Index Per Article: 42.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 03/12/2018] [Accepted: 03/15/2018] [Indexed: 12/15/2022]
Abstract
Itch is a unique sensory experience that is encoded by genetically distinguishable neurons both in the peripheral nervous system (PNS) and central nervous system (CNS) to elicit a characteristic behavioral response (scratching). Itch interacts with the other sensory modalities at multiple locations, from its initiation in a particular dermatome to its transmission to the brain where it is finally perceived. In this review, we summarize the current understanding of the molecular and neural mechanisms of itch by starting in the periphery, where itch is initiated, and discussing the circuits involved in itch processing in the CNS.
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Affiliation(s)
- Xintong Dong
- The Solomon H. Snyder Department of Neuroscience and the Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience and the Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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Mochizuki H, Hernandez LE, Yosipovitch G, Sadato N, Kakigi R. The Functional Network Processing Acute Electrical Itch Stimuli in Humans. Front Physiol 2019; 10:555. [PMID: 31156452 PMCID: PMC6529842 DOI: 10.3389/fphys.2019.00555] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 04/23/2019] [Indexed: 01/31/2023] Open
Abstract
The posterior insula (pIns) is a major brain region that receives itch-related signals from the periphery and transfers these signals to broad areas in the brain. Previous brain imaging studies have successfully identified brain regions that respond to itch stimuli. However, it is still unknown which brain regions receive and process itch-related signals from the pIns. Addressing this question is important in identifying key functional networks that process itch. Thus, the present study investigated brain regions with significantly increased functional connectivity with the pIns during itch stimuli with 25 healthy subjects by using functional MRI. Electrical itch stimuli was applied to the left wrist. Similar to previous brain imaging studies, many cortical and subcortical areas were activated by itch stimuli. However, not all of these regions showed significant increments of functional connectivity with the pIns during itch stimuli. While the subjects perceived the itch sensation, functional connectivity was significantly increased between the right pIns and the supplementary motor area (SMA), pre-SMA, anterior midcingulate cortex (aMCC), anterior insula (aIns), secondary somatosensory cortex (SII), and basal ganglia (BG), suggesting that this is a key network in processing itch. In particular, intensity of functional connectivity between the pIns and BG was negatively correlated with itch rating. The functional pIns-BG pathway may play an important role in regulation of subjective itch sensation. This study first identified a key brain network to process itch.
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Affiliation(s)
- Hideki Mochizuki
- Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, Miami Itch Center, Miller School of Medicine, University of Miami, Miami, FL, United States.,Department of Integrative Physiology, National Institute for Physiological Sciences, Okazaki, Japan
| | - Loren E Hernandez
- Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, Miami Itch Center, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Gil Yosipovitch
- Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, Miami Itch Center, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Norihiro Sadato
- Department of System Neuroscience, National Institute for Physiological Sciences, Okazaki, Japan
| | - Ryusuke Kakigi
- Department of Integrative Physiology, National Institute for Physiological Sciences, Okazaki, Japan
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Min S, Kim KW, Jung WM, Lee MJ, Kim YK, Chae Y, Lee H, Park HJ. Acupuncture for Histamine-Induced Itch: Association With Increased Parasympathetic Tone and Connectivity of Putamen-Midcingulate Cortex. Front Neurosci 2019; 13:215. [PMID: 30914919 PMCID: PMC6423085 DOI: 10.3389/fnins.2019.00215] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 02/25/2019] [Indexed: 12/19/2022] Open
Abstract
Previous studies have suggested that acupuncture is effective for ameliorating itch intensity. However, factors associated with the antipruritic effects of acupuncture have yet to be clarified. In a randomized, sham-controlled, crossover trial, we investigated the antipruritic effects of acupuncture against histamine-induced itch in healthy volunteers. Autonomic changes using heart rate variability (HRV) and brain connectivity using functional magnetic resonance imaging (fMRI) were also assessed to identify physiological factors associated with the acupuncture response. Acupuncture significantly reduced itch intensity and skin blood perfusion as assessed by laser Doppler perfusion imaging compared to sham control, indicating the antipruritic effects of acupuncture. In responder and non-responder analysis, the power of normalized high frequency (HF norm) was significantly higher, while the power of normalized low frequency (LF norm) and LF/HF ratio were significantly lower in responders compared to non-responders, suggesting the acupuncture response involved parasympathetic activation. In fMRI analysis, the putamen and the posterior part of the midcingulate cortex (pMCC) were positively connected to itch and negatively correlated with itch intensity in responders. These results suggest that parasympathetic activity and functional connectivity of the putamen and pMCC could be associated with antipruritic response to acupuncture.
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Affiliation(s)
- Seorim Min
- Department of Science in Korean Medicine, Graduate School, College of Korean Medicine, Kyung Hee University, Seoul, South Korea.,Acupuncture and Meridian Science Research Center, Kyung Hee University, Seoul, South Korea
| | - Koh-Woon Kim
- Department of Korean Rehabilitation Medicine, College of Korean Medicine, Kyung Hee University, Seoul, South Korea.,East-West Medical Research Institute, Kyung Hee University, Seoul, South Korea
| | - Won-Mo Jung
- Department of Science in Korean Medicine, Graduate School, College of Korean Medicine, Kyung Hee University, Seoul, South Korea.,Acupuncture and Meridian Science Research Center, Kyung Hee University, Seoul, South Korea
| | - Min-Jung Lee
- Acupuncture and Meridian Science Research Center, Kyung Hee University, Seoul, South Korea
| | - Yu-Kang Kim
- Department of Science in Korean Medicine, Graduate School, College of Korean Medicine, Kyung Hee University, Seoul, South Korea.,Acupuncture and Meridian Science Research Center, Kyung Hee University, Seoul, South Korea
| | - Younbyoung Chae
- Department of Science in Korean Medicine, Graduate School, College of Korean Medicine, Kyung Hee University, Seoul, South Korea.,Acupuncture and Meridian Science Research Center, Kyung Hee University, Seoul, South Korea
| | - Hyangsook Lee
- Department of Science in Korean Medicine, Graduate School, College of Korean Medicine, Kyung Hee University, Seoul, South Korea.,Acupuncture and Meridian Science Research Center, Kyung Hee University, Seoul, South Korea
| | - Hi-Joon Park
- Department of Science in Korean Medicine, Graduate School, College of Korean Medicine, Kyung Hee University, Seoul, South Korea.,Acupuncture and Meridian Science Research Center, Kyung Hee University, Seoul, South Korea
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26
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27
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Ehling S, Butler A, Thi S, Ghashghaei HT, Bäumer W. To scratch an itch: Establishing a mouse model to determine active brain areas involved in acute histaminergic itch. IBRO Rep 2018; 5:67-73. [PMID: 30364768 PMCID: PMC6197726 DOI: 10.1016/j.ibror.2018.10.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 10/13/2018] [Indexed: 12/30/2022] Open
Abstract
The specific histamine H4 receptor agonist ST-1006 induces acute itch in mice. Histaminergic itch increases neuronal activity in the medial habenula. Selective H4R activation in the skin increases neuronal activity in the medial habenula.
Background Strategies to efficiently control itch require a deep understanding of the underlying mechanisms. Several areas in the brain involved in itch and scratching responses have been postulated, but the central mechanisms that drive pruritic responses are still unknown. Histamine is recognized as a major mediator of itch in humans, and has been the most frequently used stimulus as an experimental pruritogen for brain imaging of itch. Objective Histaminergic itch via histamine and the selective histamine H4 receptor (H4R) agonist, ST-1006, recruit brain nuclei through c-fos activation and activate specific areas in the brain. Methods An acute itch model was established in c-fos-EGFP transgenic mice using ST-1006 and histamine. Coronal brain sections were stained for c-fos immunoreactivity and the forebrain was mapped for density of c-fos + nuclei. Results Histamine and ST-1006 significantly increased scratching response in c-fos-EGFP mice compared to vehicle controls. Mapping c-fos immunostained brain sections revealed neuronal activity in the cortex, striatum, hypothalamus, thalamus, amygdala, and the midbrain. Conclusions Histaminergic itch and selective H4R activation significantly increased the density of c-fos + nuclei in the medial habenula (MHb). Thus, the MHb may be a new target to investigate and subsequently develop novel mechanism-based strategies to treat itch and possibly provide a locus for pharmacological control of pruritus.
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Affiliation(s)
- Sarah Ehling
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, NC, USA.,Institute of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Ashley Butler
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, NC, USA
| | - Stephanie Thi
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, NC, USA
| | - H Troy Ghashghaei
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, NC, USA
| | - Wolfgang Bäumer
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, NC, USA.,Institute of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
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28
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Wang Y, Fang J, Song P, Bao Y, Song W, Liu J, Lang C, Jorgenson K, Jung M, Shen D, Li S, Sun R, Ding X, Yang J, Meng X, Wang N, Yan Z, Yan Y, Kong Q, Dong Y, Cui F, Tu Y, Cui B, Kong J. The Dysfunction of the Cerebellum and Its Cerebellum-Reward-Sensorimotor Loops in Chronic Spontaneous Urticaria. CEREBELLUM (LONDON, ENGLAND) 2018; 17:507-516. [PMID: 29574551 PMCID: PMC6126981 DOI: 10.1007/s12311-018-0933-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Chronic spontaneous urticaria (CSU) is a common itchy skin disease. Despite its prevalence, the neuropathology of CSU is uncertain. In this study, we explored resting state functional connectivity (rs-FC) changes in CSU, as well as how the symptom changes following intervention can modulate rs-FC. Forty patients and 40 healthy controls (HCs) were recruited. Following an intervention, 32 patients participated in a second scan approximately 6 weeks after the first scan. Compared with healthy controls, CSU subjects exhibited higher regional homogeneity (ReHo) values in the cerebellum, which were positively associated with urticaria activity scores over 7 days (UAS7) at baseline. After an intervention accompanied with clinical improvement, we found that ReHo values decreased at the cerebellum and increased at the bilateral primary somatosensory cortex (SI)/primary motor cortex (MI)/supplementary motor area (SMA). Using the cerebellum as a seed, CSU subjects exhibited increased rs-FC with reward regions when compared with HCs and exhibited decreased rs-FC at the right orbitofrontal cortex and right sensorimotor region following the intervention. The improvement rate values were positively associated with reduced rs-FC values in the two regions. Using the cluster of SI/MI/SMA as a seed, CSU patients exhibited decreased rs-FC with the left putamen, caudate, accumbens, and thalamus following the intervention. These results demonstrate the altered cerebellar activity and cerebellum-reward-sensorimotor loops in CSU.
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Affiliation(s)
- Yuming Wang
- Department of Dermatology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA
| | - Jiliang Fang
- Department of Radiology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China
| | - Ping Song
- Department of Dermatology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China
| | - Yan Bao
- Department of Radiology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China
| | - Wenwen Song
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA
| | - Jiao Liu
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA
- National-Local Joint Engineering Research Center of Rehabilitation Medicine Technology, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian, 350122, China
| | - Courtney Lang
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA
| | - Kristen Jorgenson
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA
| | - Minyoung Jung
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA
| | - Dong Shen
- Department of Dermatology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China
| | - Shasha Li
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA
| | - Ruirui Sun
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA
| | - Xu Ding
- Department of Dermatology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China
| | - Jiao Yang
- Department of Dermatology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China
| | - Xiao Meng
- Department of Dermatology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China
| | - Ning Wang
- Department of Dermatology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China
| | - Zhifang Yan
- Department of Dermatology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China
| | - Yuhe Yan
- Department of Dermatology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China
| | - Qian Kong
- Department of Dermatology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China
| | - Ying Dong
- Department of Dermatology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China
| | - Fangyuan Cui
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA
| | - Yiheng Tu
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA
| | - Bingnan Cui
- Department of Dermatology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China.
| | - Jian Kong
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA.
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29
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Andersen HH, Akiyama T, Nattkemper LA, van Laarhoven A, Elberling J, Yosipovitch G, Arendt-Nielsen L. Alloknesis and hyperknesis—mechanisms, assessment methodology, and clinical implications of itch sensitization. Pain 2018; 159:1185-1197. [DOI: 10.1097/j.pain.0000000000001220] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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30
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Huber M, Wolf RC, Lepping P, Kirchler E, Karner M, Sambataro F, Herrnberger B, Corlett PR, Freudenmann RW. Regional gray matter volume and structural network strength in somatic vs. non-somatic delusional disorders. Prog Neuropsychopharmacol Biol Psychiatry 2018; 82:115-122. [PMID: 29180231 DOI: 10.1016/j.pnpbp.2017.11.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 11/11/2017] [Accepted: 11/23/2017] [Indexed: 12/31/2022]
Abstract
BACKGROUND Monothematic delusional disorders are characterized by a single tenacious belief. They provide a great opportunity to study underlying brain structures in the absence of confounding symptoms that accompany delusions in schizophrenia. Delusional beliefs include persecution, jealousy or somatic delusions including infestation. It is unclear whether specific delusional content is associated with distinct neural substrates. METHODS We used magnetic resonance imaging in patients presenting with somatic vs. non-somatic delusional disorders. Patients with delusional infestation (DI, n=18), and individuals with non-somatic delusional disorders (n=19) were included, together with healthy volunteers (n=20). Uni- and multivariate techniques for structural data analysis were applied to provide a comprehensive characterization of abnormal brain volume at both the regional and neural network level. RESULTS Patients with DI showed lower gray matter volume in thalamic, striatal (putamen), insular and medial prefrontal brain regions in contrast to non-somatic delusional disorders and healthy controls. Importantly, these differences were consistently detected at regional and network level. Compared to healthy controls, patients with delusional disorders other than DI showed lower gray matter volume in temporal cortical regions. CONCLUSION The data support the notion that dysfunctional somatosensory and peripersonal networks could mediate somatic delusions in patients with DI in contrast to delusional disorders without somatic content. The data also suggest putative content-specific neural signatures in delusional disorders and in delusion formation per se.
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Affiliation(s)
- Markus Huber
- Department of Psychiatry, General Hospital Bruneck, South Tyrol, Italy
| | - Robert Christian Wolf
- Department of General Psychiatry, Center for Psychosocial Medicine, Heidelberg University, Germany.
| | - Peter Lepping
- Betsi Cadwaladr University Health Board, Maelor Hospital, Centre for Mental Health and Society, Wrexham, Wales, UK
| | - Erwin Kirchler
- Department of Psychiatry, General Hospital Bruneck, South Tyrol, Italy
| | - Martin Karner
- Department of Radiology, General Hospital Bruneck, South Tyrol, Italy
| | - Fabio Sambataro
- Department of Experimental & Clinical Medical Sciences, Udine University, Italy
| | | | - Philip R Corlett
- Department of Psychiatry, Yale University, Connecticut Mental Health Center, New Haven, CT, USA
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31
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The vicious cycle of itch and anxiety. Neurosci Biobehav Rev 2018; 87:17-26. [PMID: 29374516 DOI: 10.1016/j.neubiorev.2018.01.009] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 12/28/2017] [Accepted: 01/21/2018] [Indexed: 12/21/2022]
Abstract
Chronic itch is associated with increased stress, anxiety, and other mood disorders. In turn, stress and anxiety exacerbate itch, leading to a vicious cycle that affects patient behavior (scratching) and worsens disease prognosis and quality of life. This cycle persists across chronic itch conditions of different etiologies and even to some extent in healthy individuals, suggesting that the final common pathway for itch processing (the central nervous system) plays a major role in the relationship between itch and anxiety. Pharmacological and nonpharmacological treatments that reduce anxiety have shown promising anti-itch effects. Further research is needed to establish specific central mechanisms of the itch-anxiety cycle and provide new targets for treatment.
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32
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Nocebo-induced modulation of cerebral itch processing - An fMRI study. Neuroimage 2017; 166:209-218. [PMID: 29107770 DOI: 10.1016/j.neuroimage.2017.10.056] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 10/12/2017] [Accepted: 10/25/2017] [Indexed: 12/29/2022] Open
Abstract
It has been shown repeatedly that perceiving itch-related pictures or listening to a lecture on itch can enhance itch sensation and scratching behaviour (Niemeier and Gieler, 2000; Holle et al., 2012; Lloyd et al., 2013), indicating that itch is strongly influenced by expectations. Using fMRI, we investigated the neural correlates of the itch-related nocebo effect in healthy male and female human subjects. Itch sensation on the left forearm was induced by cutaneous histamine application and thermally modulated, with cooling leading to higher itch. Nocebo-induced aggravation of histaminergic itch was achieved by ostensibly treating volunteers with "transcutaneous electrical nerve stimulation (TENS)" about which subjects were instructed that it would increase itch. During a conditioning phase subjects indeed experienced stronger itch due to slightly altered cooling and histamine concentrations, but attributed it to the alleged "TENS stimulation". Importantly, in the subsequent test phase where no "TENS" or electrical stimulation was applied, volunteers significantly reported stronger itch during the nocebo as compared to the control condition. Comparing BOLD responses during nocebo in contrast to control, we observed increased activity in contralateral (right) rolandic operculum. Opercular involvement was repeatedly reported in studies related to the expectation of stimulus intensification and might thus represent an early area integrating expectation information with somatosensory information. Finally, functional coupling between the insula and the periaqueductal gray (PAG) was enhanced specifically in the nocebo condition. This cortex-PAG interaction indicates that context-dependent top-down modulation during itch might represent a shared mechanism with other modalities such as pain.
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Bartels DJP, van Laarhoven AIM, Stroo M, Hijne K, Peerdeman KJ, Donders ART, van de Kerkhof PCM, Evers AWM. Minimizing nocebo effects by conditioning with verbal suggestion: A randomized clinical trial in healthy humans. PLoS One 2017; 12:e0182959. [PMID: 28910291 PMCID: PMC5598922 DOI: 10.1371/journal.pone.0182959] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 07/25/2017] [Indexed: 11/19/2022] Open
Abstract
Nocebo effects, i.e., adverse treatment effects which are induced by patients' expectations, are known to contribute to the experience of physical symptoms such as pain and itch. A better understanding of how to minimize nocebo responses might eventually contribute to enhanced treatment effects. However, little is known about how to reduce nocebo effects. In the current randomized controlled study, we tested whether nocebo effects can be minimized by positive expectation induction with respect to electrical and histaminic itch stimuli. First, negative expectations about electrical itch stimuli were induced by verbal suggestion and conditioning (part 1: induction of nocebo effect). Second, participants were randomized to either the experimental group or one of the control groups (part 2: reversing nocebo effect). In the experimental group, positive expectations were induced by conditioning with verbal suggestion. In the control groups either the negative expectation induction was continued or an extinction procedure was applied. Afterwards, a histamine application test was conducted. Positive expectation induction resulted in a significantly smaller nocebo effect in comparison with both control groups. Mean change itch NRS scores showed that the nocebo effect was even reversed, indicating a placebo effect. Comparable effects were also found for histamine application. This study is the first to demonstrate that nocebo effects can be minimized and even reversed by conditioning with verbal suggestion. The results of the current study indicate that learning via counterconditioning and verbal suggestion represents a promising strategy for diminishing nocebo responses.
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Affiliation(s)
- Danielle J. P. Bartels
- Unit Health, Medical and Neuropsychology, Institute of Psychology, Leiden University, Leiden, the Netherlands
- Leiden Institute for Brain and Cognition (LIBC), Leiden University, Leiden, the Netherlands
- * E-mail:
| | - Antoinette I. M. van Laarhoven
- Unit Health, Medical and Neuropsychology, Institute of Psychology, Leiden University, Leiden, the Netherlands
- Leiden Institute for Brain and Cognition (LIBC), Leiden University, Leiden, the Netherlands
| | - Michiel Stroo
- Unit Health, Medical and Neuropsychology, Institute of Psychology, Leiden University, Leiden, the Netherlands
| | - Kim Hijne
- Unit Health, Medical and Neuropsychology, Institute of Psychology, Leiden University, Leiden, the Netherlands
| | - Kaya J. Peerdeman
- Unit Health, Medical and Neuropsychology, Institute of Psychology, Leiden University, Leiden, the Netherlands
- Leiden Institute for Brain and Cognition (LIBC), Leiden University, Leiden, the Netherlands
| | - A. Rogier T. Donders
- Department for Health Evidence, Radboud University Medical Center, Nijmegen, the Netherlands
| | | | - Andrea W. M. Evers
- Unit Health, Medical and Neuropsychology, Institute of Psychology, Leiden University, Leiden, the Netherlands
- Leiden Institute for Brain and Cognition (LIBC), Leiden University, Leiden, the Netherlands
- Department of Medical Psychology, Radboud University Medical Center, Nijmegen, the Netherlands
- Department of Psychiatry, Leiden University Medical Center, Leiden, the Netherlands
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34
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Schut C, Mochizuki H, Grossman SK, Lin AC, Conklin CJ, Mohamed FB, Gieler U, Kupfer J, Yosipovitch G. Brain Processing of Contagious Itch in Patients with Atopic Dermatitis. Front Psychol 2017; 8:1267. [PMID: 28790959 PMCID: PMC5524890 DOI: 10.3389/fpsyg.2017.01267] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 07/11/2017] [Indexed: 11/13/2022] Open
Abstract
Several studies show that itch and scratching cannot only be induced by pruritogens like histamine or cowhage, but also by the presentation of certain (audio-) visual stimuli like pictures on crawling insects or videos showing other people scratching. This phenomenon is coined "Contagious itch" (CI). Due to the fact that CI is more profound in patients with the chronic itchy skin disease atopic dermatitis (AD), we believe that it is highly relevant to study brain processing of CI in this group. Knowledge on brain areas involved in CI in AD-patients can provide us with useful hints regarding non-invasive treatments that AD-patients could profit from when they are confronted with itch-inducing situations in daily life. Therefore, this study investigated the brain processing of CI in AD-patients. 11 AD-patients underwent fMRI scans during the presentation of an itch inducing experimental video (EV) and a non-itch inducing control video (CV). Perfusion based brain activity was measured using arterial spin labeling functional MRI. As expected, the EV compared to the CV led to an increase in itch and scratching (p < 0.05). CI led to a significant increase in brain activity in the supplementary motor area, left ventral striatum and right orbitofrontal cortex (threshold: p < 0.001; cluster size k > 50). Moreover, itch induced by watching the EV was by trend correlated with activity in memory-related regions including the temporal cortex and the (pre-) cuneus as well as the posterior operculum, a brain region involved in itch processing (threshold: p < 0.005; cluster size k > 50). These findings suggest that the fronto-striatal circuit, which is associated with the desire to scratch, might be a target region for non-invasive treatments in AD patients.
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Affiliation(s)
- Christina Schut
- Institute of Medical Psychology, Justus-Liebig-UniversityGiessen, Germany
| | - Hideki Mochizuki
- Department of Dermatology, Lewis Katz School of Medicine at Temple University, PhiladelphiaPA, United States
- Department of Dermatology and Cutaneous Surgery and Miami Itch Center, Miller School of Medicine, University of Miami, MiamiFL, United States
| | - Shoshana K. Grossman
- Department of Dermatology, Lewis Katz School of Medicine at Temple University, PhiladelphiaPA, United States
| | - Andrew C. Lin
- Department of Dermatology, Lewis Katz School of Medicine at Temple University, PhiladelphiaPA, United States
| | - Christopher J. Conklin
- Department of Radiology, Jefferson Integrated Magnetic Resonance Imaging Center, Thomas Jefferson University, PhiladelphiaPA, United States
| | - Feroze B. Mohamed
- Department of Radiology, Jefferson Integrated Magnetic Resonance Imaging Center, Thomas Jefferson University, PhiladelphiaPA, United States
| | - Uwe Gieler
- Department of Dermatology, University Hospital of Giessen and MarburgGiessen, Germany
| | - Joerg Kupfer
- Institute of Medical Psychology, Justus-Liebig-UniversityGiessen, Germany
| | - Gil Yosipovitch
- Department of Dermatology and Cutaneous Surgery and Miami Itch Center, Miller School of Medicine, University of Miami, MiamiFL, United States
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Hirjak D, Huber M, Kirchler E, Kubera KM, Karner M, Sambataro F, Freudenmann RW, Wolf RC. Cortical features of distinct developmental trajectories in patients with delusional infestation. Prog Neuropsychopharmacol Biol Psychiatry 2017; 76:72-79. [PMID: 28257853 DOI: 10.1016/j.pnpbp.2017.02.018] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 02/23/2017] [Accepted: 02/27/2017] [Indexed: 01/02/2023]
Abstract
BACKGROUND Although there is strong neuroimaging evidence that cortical alterations are a core feature of schizophrenia spectrum disorders, it still remains unclear to what extent such abnormalities occur in monothematic delusional disorders. In individuals with delusional infestation (DI), the delusional belief to be infested with pathogens, previous structural MRI studies have shown prefrontal, temporal, parietal, insular, thalamic and striatal gray matter volume changes. Differential contributions of cortical features of evolutionary and genetic origin (such as cortical thickness, area and folding) which may distinctly contribute to DI pathophysiology are unclear at present. METHODS In this study, 18 patients with DI and 20 healthy controls (HC) underwent MRI scanning at 1.0T. Using surface-based analyses we calculated cortical thickness, surface area and local gyrification index (LGI). Whole-brain differences between patients and controls were investigated. RESULTS Surface analyses revealed frontoparietal patterns exhibiting altered cortical thickness, surface area and LGI in DI patients compared to controls. Higher cortical thickness was found in the right medial orbitofrontal cortex (p<0.05, cluster-wise probability [CWP] corrected). Smaller surface area in patients was found in the left inferior temporal gyrus, the precuneus, the pars orbitalis of the right frontal gyrus, and the lingual gyrus (p<0.05, CWP corr.). Lower LGI was found in the left postcentral, bilateral precentral, right middle temporal, inferior parietal, and superior parietal gyri (p<0.01, CWP corr.). CONCLUSION This study lends further support to the hypothesis that cortical features of distinct evolutionary and genetic origin differently contribute to the pathogenesis of delusional disorders. Regions in which atrophy was observed are part of neural circuits associated with perception, visuospatial control and self-awareness. The data are in line with the notion of a content-specific neural signature of DI.
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Affiliation(s)
- Dusan Hirjak
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University Mannheim, Germany.
| | - Markus Huber
- Department of Psychiatry, General Hospital Bruneck, South Tyrol, Italy
| | - Erwin Kirchler
- Department of Psychiatry, General Hospital Bruneck, South Tyrol, Italy
| | - Katharina M Kubera
- Center for Psychosocial Medicine, Department of General Psychiatry, Heidelberg University, Germany
| | - Martin Karner
- Department of Radiology, General Hospital Bruneck, South Tyrol, Italy
| | - Fabio Sambataro
- Department of Experimental and Clinical Medical Sciences, Udine University, Italy
| | | | - Robert C Wolf
- Center for Psychosocial Medicine, Department of General Psychiatry, Heidelberg University, Germany
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Lee JS, Han JS, Lee K, Bang J, Lee H. The peripheral and central mechanisms underlying itch. BMB Rep 2017; 49:474-87. [PMID: 27418284 PMCID: PMC5227140 DOI: 10.5483/bmbrep.2016.49.9.108] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Indexed: 12/20/2022] Open
Abstract
Itch is one of the most distressing sensations that substantially impair quality of life. It is a cardinal symptom of many skin diseases and is also caused by a variety of systemic disorders. Unfortunately, currently available itch medications are ineffective in many chronic itch conditions, and they often cause undesirable side effects. To develop novel therapeutic strategies, it is essential to identify primary afferent neurons that selectively respond to itch mediators as well as the central nervous system components that process the sensation of itch and initiate behavioral responses. This review summarizes recent progress in the study of itch, focusing on itch-selective receptors, signaling molecules, neuronal pathways from the primary sensory neurons to the brain, and potential decoding mechanisms based on which itch is distinguished from pain. [BMB Reports 2016; 49(9): 474-487]
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Affiliation(s)
- Jae Seung Lee
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Korea
| | | | - Kyeongho Lee
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Korea
| | - Juwon Bang
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Korea
| | - Hyosang Lee
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Korea
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Mochizuki H, Schut C, Nattkemper LA, Yosipovitch G. Brain mechanism of itch in atopic dermatitis and its possible alteration through non-invasive treatments. Allergol Int 2017; 66:14-21. [PMID: 27688121 DOI: 10.1016/j.alit.2016.08.013] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 08/30/2016] [Indexed: 01/19/2023] Open
Abstract
Atopic dermatitis (AD) is a common chronic skin disease that is characterized by intense pruritus and has high impairment of quality of life. AD is often described as "the itch that rashes, rather than the rash that itches". Several studies suggest that mechanisms of central modulation play an important role in the development and maintenance of chronic itch. Therefore, treating the neurosensory aspects of itch is an important part in the management of chronic itch. However, little attention has been paid to the role of the central nervous system in the processing of itch in AD. Targeting itch-related anatomical structures in the brain with non-invasive treatments such as psychological interventions and transcranial Direct Current Stimulation (tDCS) could have an antipruritic effect in AD. Therefore, in this review article, we discuss the current progress in brain imaging research of itch, as well as the efficacy of non-invasive interventions for itch relief in this patient group.
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Affiliation(s)
- Hideki Mochizuki
- Department of Dermatology, Lewis Katz School of Medicine, Philadelphia, PA, USA; Temple Itch Center, Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Christina Schut
- Institute of Medical Psychology, Justus-Liebig-University, Giessen, Germany
| | - Leigh A Nattkemper
- Department of Dermatology, Lewis Katz School of Medicine, Philadelphia, PA, USA; Temple Itch Center, Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Gil Yosipovitch
- Department of Dermatology and Cutaneous Surgery, Miller School of Medicine, University of Miami, Miami, USA.
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Hawro T, Lehmann S, Altrichter S, Fluhr JW, Zuberbier T, Church MK, Maurer M, Metz M. Skin provocation tests may help to diagnose atopic dermatitis. Allergy 2016; 71:1745-1752. [PMID: 27472813 DOI: 10.1111/all.12995] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/26/2016] [Indexed: 11/27/2022]
Abstract
BACKGROUND Atopic dermatitis (AD) is a common skin disorder. Its diagnosis relies on clinical judgment. Mild and untypical manifestations may cause diagnostic difficulties. Biomarkers for the differential diagnostic workup of AD are needed. OBJECTIVE To test whether the results of skin provocation with cowhage, an established model of histamine-independent pruritus, and histamine are different in AD patients and healthy subjects and whether these tests may be used as diagnostic markers of AD. METHODS Twenty-two AD patients and 18 healthy controls were subjected to topical cowhage provocation and skin prick testing with histamine and assessed for differences in the quality, intensity, and persistence of itch, for wheal diameter, volume, and flare size and intensity. RESULTS Patients with AD, compared with healthy controls, exhibited significantly smaller histamine-induced flares (P < 0.01) and markedly longer itch persistence after provocation with cowhage (P < 0.01). Both parameters showed good diagnostic properties for AD (area under the receiver operating characteristic (ROC) curve 0.78 and 0.80, respectively). The persistence of cowhage-induced itch for at least 30 min and a histamine-induced flare of less than 2 cm in diameter were reliable thresholds for the diagnosis of AD. If combinations of the results of both tests were used, their sensitivity and specificity of diagnosing AD were up to 91% and 94%, respectively. CONCLUSION The clinical benefit of cowhage and histamine skin provocation tests should be investigated in further studies. Long persistence of cowhage-induced itch and diminished histamine-induced flare in nonlesional skin may support diagnosis of AD.
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Affiliation(s)
- T. Hawro
- Department of Dermatology and Allergy; Allergie-Centrum Charité; Charité-Universitätsmedizin Berlin; Berlin Germany
| | - S. Lehmann
- Department of Dermatology and Allergy; Allergie-Centrum Charité; Charité-Universitätsmedizin Berlin; Berlin Germany
| | - S. Altrichter
- Department of Dermatology and Allergy; Allergie-Centrum Charité; Charité-Universitätsmedizin Berlin; Berlin Germany
| | - J. W. Fluhr
- Department of Dermatology and Allergy; Allergie-Centrum Charité; Charité-Universitätsmedizin Berlin; Berlin Germany
| | - T. Zuberbier
- Department of Dermatology and Allergy; Allergie-Centrum Charité; Charité-Universitätsmedizin Berlin; Berlin Germany
| | - M. K. Church
- Department of Dermatology and Allergy; Allergie-Centrum Charité; Charité-Universitätsmedizin Berlin; Berlin Germany
| | - M. Maurer
- Department of Dermatology and Allergy; Allergie-Centrum Charité; Charité-Universitätsmedizin Berlin; Berlin Germany
| | - M. Metz
- Department of Dermatology and Allergy; Allergie-Centrum Charité; Charité-Universitätsmedizin Berlin; Berlin Germany
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Jeong KY, Kim HM, Kang JH. Investigation of the functional difference between the pathological itching and neuropathic pain-induced rat brain using manganese-enhanced MRI. Acta Radiol 2016; 57:861-868. [PMID: 26385912 DOI: 10.1177/0284185115604514] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 08/12/2015] [Indexed: 01/17/2023]
Abstract
BACKGROUND There is a remarkable similarity in the central sensitization of itch and pain. However, the interactions between itch and pain are only partially understood. PURPOSE To investigate the functional activity of cerebral regions to provide clear information on the neuronal pathways related to both pathological itching (PI) and neuropathic pain (NP). MATERIAL AND METHODS Sprague-Dawley rats were used in this study. PI was induced via neonatal capsaicin treatment, and scratching behavior was counted. NP was induced via lumbar spinal nerve 5 (L5) ligation, and mechanical allodynia was measured. The activated cerebral regions in the control, PI, and NP rats were measured using a 4.7 T magnetic resonance imaging (MRI) system and manganese-enhanced MRI (MEMRI). Subsequently, the cerebral activation regions were identified, and the signal intensity was compared. RESULTS Cerebral activities of the PI-induced rats were found in three regions -7.10 and -4.20 mm, and two regions -2.45 mm from the bregma. In the NP-induced rats, cerebral activities were found in two regions 7.10 and -2.45 mm, and one region -4.20 mm from the bregma. Comparing the PI and NP rats, the cerebral activities were different in one region -7.10 mm and -2.45 mm, and two regions -4.20 mm from the bregma. The different regions were the midbrain area, the geniculate complex, the hypothalamic area, and the amygdala area. CONCLUSION Our MEMRI investigation indicates functionally different activity of cerebral regions due to the effect of PI or NP. These findings provide clear information of the signal transduction in the brain regarding PI or NP that share a similar neuronal pathway.
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Affiliation(s)
- Keun-Yeong Jeong
- Gachon Institute of Pharmaceutical Science, Gachon University, Incheon, Republic of Korea
| | - Hwan Mook Kim
- Gachon Institute of Pharmaceutical Science, Gachon University, Incheon, Republic of Korea
| | - Ji-Hyuk Kang
- Department of Biomedical Laboratory Science, College of Health and Medical Science, Daejeon University, Daejeon, Republic of Korea
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Napadow V, Li A, Loggia M, Kim J, Mawla I, Desbordes G, Schalock PC, Lerner EA, Tran TN, Ring J, Rosen BR, Kaptchuk TJ, Pfab F. The imagined itch: brain circuitry supporting nocebo-induced itch in atopic dermatitis patients. Allergy 2015; 70:1485-92. [PMID: 26280659 DOI: 10.1111/all.12727] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/10/2015] [Indexed: 12/19/2022]
Abstract
BACKGROUND Psychological factors are known to significantly modulate itch in patients suffering from chronic itch. Itch is also highly susceptible to both placebo and nocebo (negative placebo) effects. Brain activity likely supports nocebo-induced itch, but is currently unknown. METHODS We collected functional MRI (fMRI) data from atopic dermatitis (AD) patients, in a within-subject design, and contrast brain response to nocebo saline understood to be allergen vs open-label saline control. Exploratory analyses compared results to real allergen itch response and placebo responsiveness, evaluated in the same patients. RESULTS Nocebo saline produced greater itch than open saline control (P < 0.01). Compared to open saline, nocebo saline demonstrated greater fMRI response in caudate, dorsolateral prefrontal cortex (dlPFC), and intraparietal sulcus (iPS) - brain regions important for cognitive executive and motivational processing. Exploratory analyses found that subjects with greater dlPFC and caudate activation to nocebo-induced itch also demonstrated greater dlPFC and caudate activation, respectively, for real allergen itch. Subjects reporting greater nocebo-induced itch also demonstrated greater placebo reduction of allergen-evoked itch, suggesting increased generalized modulation of itch perception. CONCLUSIONS Our study demonstrates the capacity of nocebo saline to mimic both the sensory and neural effects of real allergens and provides an insight to the brain mechanisms supporting nocebo-induced itch in AD, thus aiding our understanding of the role that expectations and other psychological factors play in modulating itch perception in chronic itch patients.
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Affiliation(s)
- V. Napadow
- Martinos Center for Biomedical Imaging; Massachusetts General Hospital; Harvard Medical School; Charlestown MA USA
- Department of Radiology; Logan University; Chesterfield MO USA
| | - A. Li
- Martinos Center for Biomedical Imaging; Massachusetts General Hospital; Harvard Medical School; Charlestown MA USA
| | - M.L. Loggia
- Martinos Center for Biomedical Imaging; Massachusetts General Hospital; Harvard Medical School; Charlestown MA USA
| | - J. Kim
- Martinos Center for Biomedical Imaging; Massachusetts General Hospital; Harvard Medical School; Charlestown MA USA
| | - I. Mawla
- Martinos Center for Biomedical Imaging; Massachusetts General Hospital; Harvard Medical School; Charlestown MA USA
| | - G. Desbordes
- Martinos Center for Biomedical Imaging; Massachusetts General Hospital; Harvard Medical School; Charlestown MA USA
| | - P. C. Schalock
- Department of Dermatology; Massachusetts General Hospital; Harvard Medical School; Boston MA USA
| | - E. A. Lerner
- Department of Dermatology; Massachusetts General Hospital; Harvard Medical School; Boston MA USA
| | - T. N. Tran
- Department of Dermatology; Massachusetts General Hospital; Harvard Medical School; Boston MA USA
| | - J. Ring
- Department of Dermatology and Allergy; Technische Universität München; Munich Germany
| | - B. R. Rosen
- Martinos Center for Biomedical Imaging; Massachusetts General Hospital; Harvard Medical School; Charlestown MA USA
| | - T. J. Kaptchuk
- Program in Placebo Studies; Beth Israel Deaconess Medical Center; Harvard Medical School; Boston MA USA
| | - F. Pfab
- Martinos Center for Biomedical Imaging; Massachusetts General Hospital; Harvard Medical School; Charlestown MA USA
- Department of Dermatology and Allergy; Technische Universität München; Munich Germany
- Department of Prevention and Sports Medicine; Technische Universität München; Munich Germany
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41
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Mochizuki H, Kakigi R. Itch and brain. J Dermatol 2015; 42:761-7. [DOI: 10.1111/1346-8138.12956] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 04/16/2015] [Indexed: 01/23/2023]
Affiliation(s)
- Hideki Mochizuki
- Department of Dermatology; Temple University School of Medicine; Temple Itch Center; Philadelphia Pennsylvania USA
| | - Ryusuke Kakigi
- Department of Integrative Physiology; National Institute for Physiological Sciences; Okazaki Japan
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42
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Yosipovitch G, Mochizuki H. Neuroimaging of itch as a tool of assessment of chronic itch and its management. Handb Exp Pharmacol 2015; 226:57-70. [PMID: 25861774 DOI: 10.1007/978-3-662-44605-8_4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Chronic itch is a multidimensional physical state strongly associated with emotional and cognitive aspects of suffering that causes the urge to scratch. Pathophysiology, psychological stress, and social milieu can influence itch. Here, we review brain neuroimaging research in humans that detects functional and anatomic changes in health and disease states. New data are emerging that are shaping our understanding of itch mechanisms and scratching-the behavioral response as well as the effect of treatments and brain dynamics during itch. Future developments will continue to expand our knowledge of itch mechanisms, allowing translation to clinical assessment and novel therapies focused on the brain, the final relay of itch transmission.
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Affiliation(s)
- Gil Yosipovitch
- Department of Dermatology and Temple Itch Center, Temple University Medical Center, 3322 North Broad Street, Suite 212, Philadelphia, PA, 19140, USA,
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43
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Abstract
Histamine is one of the best-characterized pruritogens in humans. It is known to play a role in pruritus associated with urticaria as well as ocular and nasal allergic reactions. Histamine mediates its effect via four receptors. Antihistamines that block the activation of the histamine H₁receptor, H₁R, have been shown to be effective therapeutics for the treatment of pruritus associated with urticaria, allergic rhinitis, and allergic conjunctivitis. However, their efficacy in other pruritic diseases such as atopic dermatitis and psoriasis is limited. The other histamine receptors may also play a role in pruritus, with the exception of the histamine H₂receptor, H₂R. Preclinical evidence indicates that local antagonism of the histamine H₃receptor, H₃R, can induce scratching perhaps via blocking inhibitory neuronal signals. The histamine H₄receptor, H₄R, has received a significant amount of attention as to its role in mediating pruritic signals. Indeed, it has now been shown that a selective H₄R antagonist can inhibit histamine-induced itch in humans. This clinical result, in conjunction with efficacy in various preclinical pruritus models, points to the therapeutic potential of H₄R antagonists for the treatment of pruritus not controlled by antihistamines that target the H₁R.
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Affiliation(s)
- Robin L Thurmond
- Janssen Research and Development, L.L.C., San Diego, CA, 92121, USA,
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44
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Abstract
Pruritus is defined as "an unpleasant sensation that causes the need to scratch". This is not a small pain. It seems that pruriceptors exist but their level of separation from nociceptive receptors is still debated. Pathways of pruritus were identified from the skin (around the dermo-epidermal junction) to the brain. Many mediators are involved in pruritus but there are at least a histaminergic and a non-histaminergic pathway (PAR-2dependent). Similarly to pain, gate control or peripheral and central sensitization mechanisms have been highlighted in pruritus. These pathophysiological advances are important and anticipate therapeutic advances, that will be very useful for the symptomatic treatment of pruritus (poorly efficient at present).
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Affiliation(s)
- Laurent Misery
- Laboratoire des neurosciences de Brest (EA4685), université de Bretagne occidentale, faculté de médecine, rue Camille Desmoulins, 29200 Brest, France service de dermatologie, CHU de Brest, 2, avenue Foch, 29200 Brest, France
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45
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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: 33] [Impact Index Per Article: 3.0] [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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46
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Mochizuki H, Kakigi R. Central mechanisms of itch. Clin Neurophysiol 2014; 126:1650-60. [PMID: 25534483 DOI: 10.1016/j.clinph.2014.11.019] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 10/31/2014] [Accepted: 11/18/2014] [Indexed: 10/24/2022]
Abstract
Itch is a complex sensory and emotional experience. Functional brain imaging studies have been performed to identify brain regions associated with this complex experience, and these studies reported that several brain regions are activated by itch stimuli. The possible roles of these regions in itch perception and difference in cerebral mechanism between healthy subjects and chronic itch patients are discussed in this review article. Additionally, the central itch modulation system and cerebral mechanisms of contagious itch, pleasurable sensation evoked by scratching have also been investigated in previous brain imaging studies. We also discuss how these studies advance our understanding of these mechanisms.
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Affiliation(s)
- Hideki Mochizuki
- Department of Integrative Physiology, National Institute for Physiological Sciences, Okazaki, Aichi, Japan; Department of Dermatology and Temple Itch Center, Temple University School of Medicine, Philadelphia, PA, USA.
| | - Ryusuke Kakigi
- Department of Integrative Physiology, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
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47
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Papoiu ADP, Emerson NM, Patel TS, Kraft RA, Valdes-Rodriguez R, Nattkemper LA, Coghill RC, Yosipovitch G. Voxel-based morphometry and arterial spin labeling fMRI reveal neuropathic and neuroplastic features of brain processing of itch in end-stage renal disease. J Neurophysiol 2014; 112:1729-38. [PMID: 24944217 DOI: 10.1152/jn.00827.2013] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Pruritus of end-stage renal disease (ESRD) is a multifactorial symptom of complex etiology not yet fully understood. In this study we have investigated the cerebral perfusion patterns at rest in ESRD patients on hemodialysis, compared with those in healthy volunteers. We have also studied the brain responses evoked by experimental itch induction in ESRD, after stimulating the two distinct histamine and cowhage itch pathways, and compared them with the responses evoked in healthy volunteers. To identify potential structural alterations in ESRD patients compared with a group of age-matched healthy volunteers, we calculated the density of gray matter for the entire brain using a voxel-based morphometric analysis. Our results indicated that gray matter density was significantly reduced in ESRD patients in the frontal, parietal, temporal, and occipital cortices, as well as in the S1, precuneus, and insula, whereas the brain stem, hippocampus, amygdala, midcingulate cortex, and nucleus accumbens displayed an increased gray matter density. Functionally, we found a significantly higher brain perfusion at baseline associated with ESRD pruritus in the anterior cingulate, insula, claustrum, hippocampus, and nucleus accumbens. The brain responses evoked by cowhage itch, which are mediated by protease-activated receptors (PAR2), displayed significant differences compared with responses in healthy individuals and were correlated with perceived itch intensity in a dual, complex manner. The inverse correlations in particular suggested that a negative feedback mechanism modulated itch intensity, when elicited in a preexistent chronic itch background.
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Affiliation(s)
- Alexandru D P Papoiu
- Department of Dermatology, Wake Forest School of Medicine, Winston-Salem, North Carolina;
| | - Nichole M Emerson
- Department of Neurobiology & Anatomy, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Tejesh S Patel
- Department of Dermatology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Robert A Kraft
- Department of Biomedical Engineering, Virginia Polytechnic Institute and Wake Forest University, Winston-Salem, North Carolina; and
| | | | - Leigh A Nattkemper
- Department of Dermatology, Wake Forest School of Medicine, Winston-Salem, North Carolina; Department of Dermatology and Itch Center, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Robert C Coghill
- Department of Neurobiology & Anatomy, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Gil Yosipovitch
- Department of Dermatology, Wake Forest School of Medicine, Winston-Salem, North Carolina; Department of Neurobiology & Anatomy, Wake Forest School of Medicine, Winston-Salem, North Carolina; Department of Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina; Department of Dermatology and Itch Center, Temple University School of Medicine, Philadelphia, Pennsylvania
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48
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Reich A, Szepietowski JC. Pruritus intensity assessment: challenge for clinicians. ACTA ACUST UNITED AC 2014. [DOI: 10.1586/edm.13.25] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Wolf RC, Huber M, Lepping P, Sambataro F, Depping MS, Karner M, Freudenmann RW. Source-based morphometry reveals distinct patterns of aberrant brain volume in delusional infestation. Prog Neuropsychopharmacol Biol Psychiatry 2014; 48:112-6. [PMID: 24120443 DOI: 10.1016/j.pnpbp.2013.09.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 09/26/2013] [Accepted: 09/27/2013] [Indexed: 02/05/2023]
Abstract
Little is known about the neural correlates of delusional infestation (DI), the delusional belief to be infested with pathogens. So far, evidence comes mainly from case reports and case series. We investigated brain morphology in 16 DI patients and 16 healthy controls using structural magnetic resonance imaging and a multivariate data analysis technique, i.e. source-based morphometry (SBM). In addition, we explored differences in brain structure in patient subgroups based on disease aetiology. SBM revealed two patterns exhibiting significantly (p<0.05, Bonferroni-corrected) lower grey and higher white matter volume in DI patients compared to controls. Lower grey matter volume was found in medial prefrontal cortex, anterior cingulate cortex, medial temporal lobe structures (parahippocampus and hippocampus), sensorimotor cortices, bilateral insula and thalamus and inferior parietal regions. Higher white matter volume was found in medial and middle frontal and temporal cortices, left insula and lentiform nucleus. Grey matter volume was abnormal in both "psychiatric" (primary DI and DI associated with an affective disorder) and "organic" DI (DI due to a medical condition). In contrast, aberrant white matter volume was only confirmed for the "organic" DI patient subgroup. These results suggest prefrontal, temporal, parietal, insular, thalamic and striatal dysfunction underlying DI. Moreover, the data suggest that aetiologically distinct presentations of DI share similar patterns of abnormal grey matter volume, whereas aberrant white matter volume appears to be restricted to organic cases.
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Affiliation(s)
- Robert Ch Wolf
- Center for Psychosocial Medicine, Department of General Psychiatry, University of Heidelberg, Germany.
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50
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Stumpf A, Burgmer M, Schneider G, Heuft G, Schmelz M, Phan NQ, Ständer S, Pfleiderer B. Sex differences in itch perception and modulation by distraction--an FMRI pilot study in healthy volunteers. PLoS One 2013; 8:e79123. [PMID: 24260163 PMCID: PMC3832610 DOI: 10.1371/journal.pone.0079123] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 09/18/2013] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Even though itch is a common syndrome of many diseases there is only little knowledge about sex and gender differences in pruritus, especially in central itch perception and modulation. To our knowledge, this is the first fMRI study examining sex differences in perception and its modulation by distraction. METHODS Experimental itch was induced by application of histamine (0.1 mM) via microdialysis fibers twice at the left forearm and twice at the left lower leg in 33 healthy volunteers (17 females, 16 males). The brain activation patterns were assessed by fMRI during itch without and with distraction (Stroop task). Between the various conditions, subjects were asked to rate itch intensity, desire to scratch and pain intensity. In a second experiment in 10 of the 33 volunteers histamine was replaced by saline solution to serve as control for the 'Stroop' condition. RESULTS Women generally presented higher itch intensities compared to men during itch over the course of the experiment. A more specific analysis revealed higher itch intensities and desire to scratch in women during experimental induced itch that can be reduced by distraction at the lower legs when itch is followed by 'Stroop'. In contrast, men depicted significant reduction of 'itch' by 'Stroop' at the forearms. Women depicted higher brain activation of structures responsible for integration of sensory, affective information and motor integration/planning during 'itch' and 'Stroop' condition when compared to men. No sex differences were seen in the saline control condition. CONCLUSION Women and men exhibited localisation dependent differences in their itch perception with women presenting higher itch intensities and desire to scratch. Our findings parallel clinical observations of women reporting higher itch intensities depending on itch localisation and suffering more from itch as compared to men.
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Affiliation(s)
- Astrid Stumpf
- Department of Psychosomatics and Psychotherapy, University of Muenster, Muenster, Germany
- * E-mail:
| | - Markus Burgmer
- Department of Psychosomatics and Psychotherapy, University of Muenster, Muenster, Germany
| | - Gudrun Schneider
- Department of Psychosomatics and Psychotherapy, University of Muenster, Muenster, Germany
| | - Gereon Heuft
- Department of Psychosomatics and Psychotherapy, University of Muenster, Muenster, Germany
| | - Martin Schmelz
- Department of Anesthesiology and Intensive care Medicine, Karl Feuerstein Professorship, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Ngoc Quan Phan
- Competence Center Chronic Pruritus, Department of Dermatology, University of Muenster, Muenster, Germany
| | - Sonja Ständer
- Competence Center Chronic Pruritus, Department of Dermatology, University of Muenster, Muenster, Germany
| | - Bettina Pfleiderer
- Department of Clinical Radiology, University of Muenster, Muenster, Germany
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