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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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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. [PMID: 38634841 DOI: 10.1089/derm.2023.0340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [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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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: 1] [Impact Index Per Article: 1.0] [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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Tang DL, Niziolek CA, Parrell B. Modulation of somatosensation by transcranial magnetic stimulation over somatosensory cortex: a systematic review. Exp Brain Res 2023; 241:951-977. [PMID: 36949150 PMCID: PMC10851347 DOI: 10.1007/s00221-023-06579-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 02/17/2023] [Indexed: 03/24/2023]
Abstract
Over the last three decades, transcranial magnetic stimulation (TMS) has gained popularity as a tool to modulate human somatosensation. However, the effects of different stimulation types on the multiple distinct subdomains of somatosensation (e.g., tactile perception, proprioception and pain) have not been systematically compared. This is especially notable in the case of newer theta-burst stimulation protocols now in widespread use. Here, we aimed to systematically and critically review the existing TMS literature and provide a complete picture of current knowledge regarding the role of TMS in modulating human somatosensation across stimulation protocols and somatosensory domains. Following the PRISMA guidelines, fifty-four studies were included in the current review and were compared based on their methodologies and results. Overall, findings from these studies provide evidence that different types of somatosensation can be both disrupted and enhanced by targeted stimulation of specific somatosensory areas. Some mixed results, however, were reported in the literature. We discussed possible reasons for these mixed results, methodological limitations of existing investigations, and potential avenues for future research.
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Affiliation(s)
- Ding-Lan Tang
- Department of Communication Sciences and Disorders, University of Wisconsin-Madison, Madison, WI, USA
- Waisman Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Caroline A Niziolek
- Department of Communication Sciences and Disorders, University of Wisconsin-Madison, Madison, WI, USA.
- Waisman Center, University of Wisconsin-Madison, Madison, WI, USA.
| | - Benjamin Parrell
- Department of Communication Sciences and Disorders, University of Wisconsin-Madison, Madison, WI, USA.
- Waisman Center, University of Wisconsin-Madison, Madison, WI, USA.
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Mechanisms and therapeutic targets for neuropathic itch. Curr Opin Neurobiol 2022; 75:102573. [PMID: 35689909 DOI: 10.1016/j.conb.2022.102573] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 04/05/2022] [Accepted: 05/06/2022] [Indexed: 01/04/2023]
Abstract
Neuropathic pruritus conditions arise from structural and/or functional damage of the peripheral or central nervous system. Novel findings of pruritus specific mediators and pathways strengthen the specificity theory of pruritus transmission, however electrophysiological studies suggest that focal activation of nociceptors and distinct discharge patterns of primary afferents also contribute to the development of the sensation of pruritus. A complex interplay between excitatory and inhibitory interneurons at spinal level, non-neuronal cells and descending modulation from upper centers contributes to neuronal sensitization and clinically to the chronicity of pruritus, as well as accompanying phenomena such as alloknesis and hyperknesis. Several topical, systemic and non-pharmacological therapeutic approaches directed at distinct targets are currently available.
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Böhm M. In search of the needle in a haystack: Finding a suitable serum biomarker for monitoring disease activity of systemic sclerosis. Exp Dermatol 2021; 30:880-886. [PMID: 34121239 DOI: 10.1111/exd.14403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Markus Böhm
- Department of Dermatology, University of Münster, Münster, Germany
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Abstract
Chronic pruritus, defined as an unpleasant sensation resulting in a need to scratch that lasts more than 6 weeks, is a prevalent and bothersome symptom associated with both cutaneous and systemic conditions. Due to complex pathogenesis and profuse contributing factors, chronic pruritus therapy remains challenging. Regardless of the well-established antipruritic properties of classic pharmacotherapy (topical therapy, phototherapy and systemic therapy), these methods often provide insufficient relief for affected individuals. Owing to the growing interest in the field of pruritic research, further experimental and clinical data have emerged, continuously supporting the possibility of instigating novel therapeutic measures. This review covers the most relevant current modalities remaining under investigation that possess promising perspectives of approval in the near future, especially opioidergic drugs (mu-opioid antagonists and kappa-opioid agonists), neurokinin-1 receptor antagonists, biologic drugs, Janus kinase inhibitors, ileal bile acid transporter inhibitors, aryl hydrocarbon receptor agonists and histamine H4 receptor antagonists.
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Affiliation(s)
- Radomir Reszke
- Department of Dermatology, Venereology and Allergology, Wroclaw Medical University, 1 Chalubinskiego Street, 50-368, Wrocław, Poland
| | - Piotr Krajewski
- Department of Dermatology, Venereology and Allergology, Wroclaw Medical University, 1 Chalubinskiego Street, 50-368, Wrocław, Poland
| | - Jacek C Szepietowski
- Department of Dermatology, Venereology and Allergology, Wroclaw Medical University, 1 Chalubinskiego Street, 50-368, Wrocław, Poland.
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Ständer S, Yosipovitch G. Switch to Itch—The many novel facets of pruritus research. Exp Dermatol 2019; 28:1371-1372. [DOI: 10.1111/exd.14058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Sonja Ständer
- Center for Chronic Pruritus Department of Dermatology University Hospital of Münster Germany
| | - Gil Yosipovitch
- Dr Phillip Frost Department of Dermatology and Cutaneous Surgery Miami Itch Center Miller School of Medicine Miami Florida
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