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Pang W, Zhu J, Yang K, Zhu X, Zhou W, Jiang L, Zhuang X, Liu Y, Wei J, Lu X, Yin Y, Chen Z, Xiang Y. Generation of human region-specific brain organoids with medullary spinal trigeminal nuclei. Cell Stem Cell 2024; 31:1501-1512.e8. [PMID: 39208804 DOI: 10.1016/j.stem.2024.08.004] [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: 01/10/2024] [Revised: 06/16/2024] [Accepted: 08/08/2024] [Indexed: 09/04/2024]
Abstract
Brain organoids with nucleus-specific identities provide unique platforms for studying human brain development and diseases at a finer resolution. Despite its essential role in vital body functions, the medulla of the hindbrain has seen a lack of in vitro models, let alone models resembling specific medullary nuclei, including the crucial spinal trigeminal nucleus (SpV) that relays peripheral sensory signals to the thalamus. Here, we report a method to differentiate human pluripotent stem cells into region-specific brain organoids resembling the dorsal domain of the medullary hindbrain. Importantly, organoids specifically recapitulated the development of the SpV derived from the dorsal medulla. We also developed an organoid system to create the trigeminothalamic projections between the SpV and the thalamus by fusing these organoids, namely human medullary SpV-like organoids (hmSpVOs), with organoids representing the thalamus (hThOs). Our study provides a platform for understanding SpV development, nucleus-based circuit organization, and related disorders in the human brain.
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Affiliation(s)
- Wei Pang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Jinkui Zhu
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Kexin Yang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Xiaona Zhu
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Wei Zhou
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Linlin Jiang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Xuran Zhuang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yantong Liu
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Jianfeng Wei
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Xiaoxiang Lu
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yao Yin
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Ziling Chen
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yangfei Xiang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; State Key Laboratory of Advanced Medical Materials and Devices, ShanghaiTech University, Shanghai 201210, China; Shanghai Clinical Research and Trial Center, Shanghai 201210, China.
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García-Domínguez M. Chronic pain in the elderly: Exploring cellular and molecular mechanisms and therapeutic perspectives. FRONTIERS IN AGING 2024; 5:1477017. [PMID: 39328834 PMCID: PMC11424521 DOI: 10.3389/fragi.2024.1477017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2024] [Accepted: 08/29/2024] [Indexed: 09/28/2024]
Abstract
Chronic pain is a debilitating condition frequently observed in the elderly, involving numerous pathological mechanisms within the nervous system. Diminished local blood flow, nerve degeneration, variations in fiber composition, alterations in ion channels and receptors, accompanied by the sustained activation of immune cells and release of pro-inflammatory cytokines, lead to overactivation of the peripheral nervous system. In the central nervous system, chronic pain is strongly associated with the activation of glial cells, which results in central sensitization and increased pain perception. Moreover, age-related alterations in neural plasticity and disruptions in pain inhibitory pathways can exacerbate chronic pain in older adults. Finally, the environmental influences on the development of chronic pain in the elderly must be considered. An understanding of these mechanisms is essential for developing novel treatments for chronic pain, which can significantly improve the quality of life for this vulnerable population.
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Affiliation(s)
- Mario García-Domínguez
- Program of Immunology and Immunotherapy, CIMA-Universidad de Navarra, Pamplona, Spain
- Department of Immunology and Immunotherapy, Clínica Universidad de Navarra, Pamplona, Spain
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Madrid, Spain
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Situ P, Begley C, Simpson T. The roles of neural adaptation and sensitization in contact lens discomfort. Ocul Surf 2024; 34:132-139. [PMID: 39047906 DOI: 10.1016/j.jtos.2024.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 07/03/2024] [Accepted: 07/11/2024] [Indexed: 07/27/2024]
Abstract
PURPOSE To investigate the roles of neural adaptation and sensitization in contact lens discomfort (CLD). METHODS Cooling stimuli (20 °C) were applied to the cornea in a group comprising 24 symptomatic and 25 asymptomatic contact lens (CL) wearers as well as 15 non-CL wearing controls, using a computerized Belmonte esthesiometer. The adaptation paradigm consisted of 20 repetitive stimuli at threshold, sub- and supra-threshold levels. The sensitization paradigm involved five levels of suprathreshold stimuli ranging between 1x to 2x threshold. Following each stimulus, participants rated the sensation magnitude regarding intensity, coolness and irritation. Measurements were taken with habitual CL (BL_CL), after 2 weeks of no-CL (No_CL) and after restarting habitual CL wear (ReSt_CL). RESULTS The symptomatic subjects exhibited a lower threshold but reported enhanced sensations during the adaptation and sensitization paradigm, compared to the asymptomatic and control groups (all p ≤ 0.021). At the BL_CL and ReSt_CL visits, they showed increased ratings to repeated subthreshold stimuli (p = 0.025) and greater irritation during the sensitization paradigm (p ≤ 0.032). Ratings in asymptomatic and control groups were relatively unchanged over time (p ≥ 0.181). Logistic regression revealed a link between the augmented sensory responses and increased likelihood with CLD. CONCLUSION The maladaptive sensory responses seen in CLD subjects, with reduced adaptation and heightened sensitization to ocular surface stimulation, suggest an imbalance between sensitization and adaptation in CLD. As CLD may represent a reversible subcategory of dry eye, it can serve as a human dry eye model for studying the neurosensory effect of ocular surface stimulation.
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Affiliation(s)
- Ping Situ
- School of Optometry, Indiana University, Bloomington, IN, USA.
| | - Carolyn Begley
- School of Optometry, Indiana University, Bloomington, IN, USA
| | - Trefford Simpson
- School of Optometry and Vision Science, University of Waterloo, Waterloo, Ontario, Canada
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Asiedu K. Neurophysiology of corneal neuropathic pain and emerging pharmacotherapeutics. J Neurosci Res 2024; 102:e25285. [PMID: 38284865 DOI: 10.1002/jnr.25285] [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: 08/09/2023] [Revised: 11/12/2023] [Accepted: 12/02/2023] [Indexed: 01/30/2024]
Abstract
The altered activity generated by corneal neuronal injury can result in morphological and physiological changes in the architecture of synaptic connections in the nervous system. These changes can alter the sensitivity of neurons (both second-order and higher-order projection) projecting pain signals. A complex process involving different cell types, molecules, nerves, dendritic cells, neurokines, neuropeptides, and axon guidance molecules causes a high level of sensory rearrangement, which is germane to all the phases in the pathomechanism of corneal neuropathic pain. Immune cells migrating to the region of nerve injury assist in pain generation by secreting neurokines that ensure nerve depolarization. Furthermore, excitability in the central pain pathway is perpetuated by local activation of microglia in the trigeminal ganglion and alterations of the descending inhibitory modulation for corneal pain arriving from central nervous system. Corneal neuropathic pain may be facilitated by dysfunctional structures in the central somatosensory nervous system due to a lesion, altered synaptogenesis, or genetic abnormality. Understanding these important pathways will provide novel therapeutic insight.
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Affiliation(s)
- Kofi Asiedu
- School of Optometry & Vision Science, University of New South Wales, Sydney, New South Wales, Australia
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Seyed-Razavi Y, Kenyon BM, Qiu F, Harris DL, Hamrah P. A novel animal model of neuropathic corneal pain-the ciliary nerve constriction model. Front Neurosci 2023; 17:1265708. [PMID: 38144209 PMCID: PMC10749205 DOI: 10.3389/fnins.2023.1265708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Accepted: 11/17/2023] [Indexed: 12/26/2023] Open
Abstract
Introduction Neuropathic pain arises as a result of peripheral nerve injury or altered pain processing within the central nervous system. When this phenomenon affects the cornea, it is referred to as neuropathic corneal pain (NCP), resulting in pain, hyperalgesia, burning, and photoallodynia, severely affecting patients' quality of life. To date there is no suitable animal model for the study of NCP. Herein, we developed an NCP model by constriction of the long ciliary nerves innervating the eye. Methods Mice underwent ciliary nerve constriction (CNC) or sham procedures. Safety was determined by corneal fluorescein staining to assess ocular surface damage, whereas Cochet-Bonnet esthesiometry and confocal microscopy assessed the function and structure of corneal nerves, respectively. Efficacy was assessed by paw wipe responses within 30 seconds of applying hyperosmolar (5M) saline at Days 3, 7, 10, and 14 post-constriction. Additionally, behavior was assessed in an open field test (OFT) at Days 7, 14, and 21. Results CNC resulted in significantly increased response to hyperosmolar saline between groups (p < 0.0001), demonstrating hyperalgesia and induction of neuropathic pain. Further, animals that underwent CNC had increased anxiety-like behavior in an open field test compared to controls at the 14- and 21-Day time-points (p < 0.05). In contrast, CNC did not result in increased corneal fluorescein staining or decreased sensation as compared to sham controls (p > 0.05). Additionally, confocal microscopy of corneal whole-mounts revealed that constriction resulted in only a slight reduction in corneal nerve density (p < 0.05), compared to naïve and sham groups. Discussion The CNC model induces a pure NCP phenotype and may be a useful model for the study of NCP, recapitulating features of NCP, including hyperalgesia in the absence of ocular surface damage, and anxiety-like behavior.
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Affiliation(s)
- Yashar Seyed-Razavi
- Center for Translational Ocular Immunology, Tufts Medical Center, Boston, MA, United States
- Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, United States
| | - Brendan M. Kenyon
- Center for Translational Ocular Immunology, Tufts Medical Center, Boston, MA, United States
- Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, United States
- Program in Neuroscience, Graduate School of Biomedical Sciences, Tufts University, Boston, MA, United States
| | - Fangfang Qiu
- Center for Translational Ocular Immunology, Tufts Medical Center, Boston, MA, United States
- Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, United States
| | - Deshea L. Harris
- Center for Translational Ocular Immunology, Tufts Medical Center, Boston, MA, United States
- Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, United States
| | - Pedram Hamrah
- Center for Translational Ocular Immunology, Tufts Medical Center, Boston, MA, United States
- Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, United States
- Program in Neuroscience, Graduate School of Biomedical Sciences, Tufts University, Boston, MA, United States
- Departments of Neuroscience and Immunology, Tufts University School of Medicine, Boston, MA, United States
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Sonkodi B, Marsovszky L, Csorba A, Balog A, Kopper B, Keller-Pintér A, Nagy ZZ, Resch MD. Disrupted Neural Regeneration in Dry Eye Secondary to Ankylosing Spondylitis-With a Theoretical Link between Piezo2 Channelopathy and Gateway Reflex, WDR Neurons, and Flare-Ups. Int J Mol Sci 2023; 24:15455. [PMID: 37895134 PMCID: PMC10607705 DOI: 10.3390/ijms242015455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 10/20/2023] [Accepted: 10/21/2023] [Indexed: 10/29/2023] Open
Abstract
This study aimed at analyzing the corneal neural regeneration in ankylosing spondylitis patients using in vivo corneal confocal microscopy in correlation with Langerhans cell density, morphology, and dry eye parameters. Approximately 24 ankylosing spondylitis subjects and 35 age- and gender-matched control subjects were enrolled. Data analysis showed that all corneal nerve-fiber descriptives were lower in the ankylosing spondylitis group, implicating disrupted neural regeneration. Peripheral Langerhans cell density showed a negative correlation with nerve fiber descriptions. A negative correlation between tear film break-up time and corneal nerve fiber total branch density was detected. The potential role of somatosensory terminal Piezo2 channelopathy in the pathogenesis of dry eye disease and ankylosing spondylitis is highlighted in our study, exposing the neuroimmunological link between these diseases. We hypothesized earlier that spinal neuroimmune-induced sensitization due to this somatosensory terminal primary damage could lead to Langerhans cell activation in the cornea, in association with downregulated Piezo1 channels on these cells. This activation could lead to a Th17/Treg imbalance in dry eye secondary to ankylosing spondylitis. Hence, the corneal Piezo2 channelopathy-induced impaired Piezo2-Piezo1 crosstalk could explain the disrupted neural regeneration. Moreover, the translation of our findings highlights the link between Piezo2 channelopathy-induced gateway to pathophysiology and the gateway reflex, not to mention the potential role of spinal wide dynamic range neurons in the evolution of neuropathic pain and the flare-ups in ankylosing spondylitis and dry eye disease.
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Affiliation(s)
- Balázs Sonkodi
- Department of Health Sciences and Sport Medicine, Hungarian University of Sports Science, 1123 Budapest, Hungary
| | - László Marsovszky
- Department of Ophthalmology, Semmelweis University, 1085 Budapest, Hungary; (L.M.)
| | - Anita Csorba
- Department of Ophthalmology, Semmelweis University, 1085 Budapest, Hungary; (L.M.)
| | - Attila Balog
- Department of Rheumatology and Immunology, Albert Szent-Györgyi Medical School, University of Szeged, 6725 Szeged, Hungary
| | - Bence Kopper
- Faculty of Kinesiology, Hungarian University of Sports Science, 1123 Budapest, Hungary
| | - Anikó Keller-Pintér
- Department of Biochemistry, Albert Szent-Györgyi Medical School, University of Szeged, 6725 Szeged, Hungary
| | - Zoltán Zsolt Nagy
- Department of Ophthalmology, Semmelweis University, 1085 Budapest, Hungary; (L.M.)
| | - Miklós D. Resch
- Department of Ophthalmology, Semmelweis University, 1085 Budapest, Hungary; (L.M.)
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Mogi M, Mendonza AE, Chastain J, Demirs JT, Medley QG, Zhang Q, Papillon JPN, Yang J, Gao Y, Xu Y, Stasi K. Ocular Pharmacology and Toxicology of TRPV1 Antagonist SAF312 (Libvatrep). Transl Vis Sci Technol 2023; 12:5. [PMID: 37672251 PMCID: PMC10484039 DOI: 10.1167/tvst.12.9.5] [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: 01/17/2023] [Accepted: 06/25/2023] [Indexed: 09/07/2023] Open
Abstract
Purpose To evaluate the pharmacology and toxicology of SAF312, a transient receptor potential vanilloid 1 (TRPV1) antagonist. Methods TRPV1 expression in human ocular tissues was evaluated with immunohistochemistry. Inhibition of calcium influx in Chinese hamster ovary (CHO) cells expressing human TRPV1 (hTRPV1) and selectivity of SAF312 were assessed by a fluorescent imaging plate reader assay. Ocular tissue and plasma pharmacokinetics (PK) were assessed following a single topical ocular dose of SAF312 (0.5%, 1.0%, 1.5%, 2.5%) in rabbits. Safety and tolerability of SAF312 were evaluated in rabbits and dogs. Effects of SAF312 on corneal wound healing after photorefractive keratectomy (PRK) surgery were assessed in rabbits. Results TRPV1 expression was noted in human cornea and conjunctiva. SAF312 inhibited calcium influx in CHO-hTRPV1 cells induced by pH 5.5 (2-[N-morpholino] ethanesulfonic acid), N-arachidonoylethanolamine, capsaicin, and N-arachidonoyl dopamine, with IC50 values of 5, 10, 12, and 27 nM, respectively, and inhibition appeared noncompetitive. SAF312 demonstrated high selectivity for TRPV1 (>149-fold) over other TRP channels. PK analysis showed highest concentrations of SAF312 in cornea and conjunctiva. SAF312 was found to be safe and well tolerated in rabbits and dogs up to the highest feasible concentration of 2.5%. No delay in wound healing after PRK was observed. Conclusions SAF312 is a potent, selective, and noncompetitive antagonist of hTRPV1 with an acceptable preclinical safety profile for use in future clinical trials. Translational Relevance SAF312, which was safe and well tolerated without causing delay in wound healing after PRK in rabbits, may be a potential therapeutic agent for ocular surface pain.
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Affiliation(s)
- Muneto Mogi
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | | | - James Chastain
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - John T. Demirs
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | | | - Qin Zhang
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | | | - Junzheng Yang
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Yan Gao
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - YongYao Xu
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Kalliopi Stasi
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
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Gao N, Lee PSY, Zhang J, Yu FSX. Ocular nociception and neuropathic pain initiated by blue light stress in C57BL/6J mice. Pain 2023; 164:1616-1626. [PMID: 37093736 PMCID: PMC10277230 DOI: 10.1097/j.pain.0000000000002896] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 02/03/2023] [Indexed: 04/25/2023]
Abstract
To elucidate the physiological, cellular, and molecular mechanisms responsible for initiating and sustaining ocular neuropathic pain, we created a blue-light-exposure model in C57BL/6 mice. Mice were exposed to 12 h of blue or white light followed by 12 h of darkness. Before blue light exposure, baseline tear secretion, stability, and ocular hyperalgesia were assessed by measuring hyper- or hypo-osmotic solution-induced eye wiping, wind-induced eye closing, and cold-induced eye blinking. At 1 day post-blue light exposure, alterations in hypotonic/hypertonic-induced eye-wiping, and tear film abnormalities were observed. Eye-wiping behaviors were abolished by topical anesthesia. The cold-stimulated eye-blinking and wind-stimulated eye-closing behaviors began after day 3 and their frequency further increased after day 9. Blue-light exposure reduced the density of nerve endings, and increased their tortuosity, the number of beadlike structures, and the branching of stromal nerve fibers, as assessed by whole-mount confocal microscopy. Blue-light exposure also increased TRPV1, but not TRPV4 staining intensity of corneal-projecting neurons in the trigeminal ganglia, as detected by Fluorogold retrograde labeling and immunohistochemistry. TRPV1 and substance P expression was increased, whereas CGRP expression deceased at the mRNA level in isolated corneal projecting neurons. Hence, our blue-light exposure B6 mouse model for assessing tearing and ocular hyperalgesia is useful for studying ocular pain and its underlying mechanisms. Blue-light-induced alterations in tearing and ocular hyperalgesia may be related to the elevated expression of TRPV1, SP, and/or the suppressed expression of CGRP at the ocular surface.
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Affiliation(s)
- Nan Gao
- Department of Ophthalmology, Visual and Anatomical
Sciences, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Patrick S. Y. Lee
- Department of Ophthalmology, Visual and Anatomical
Sciences, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Jitao Zhang
- Biomedical Engineering Department, Wayne State University.
6135 Woodward Ave, Integrative Biosciences Center, Detroit, MI, 48202
| | - Fu-shin X. Yu
- Department of Ophthalmology, Visual and Anatomical
Sciences, Wayne State University School of Medicine, Detroit, MI 48201, USA
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Nagy ZF, Sonkodi B, Pál M, Klivényi P, Széll M. Likely Pathogenic Variants of Ca v1.3 and Na v1.1 Encoding Genes in Amyotrophic Lateral Sclerosis Could Elucidate the Dysregulated Pain Pathways. Biomedicines 2023; 11:933. [PMID: 36979911 PMCID: PMC10046311 DOI: 10.3390/biomedicines11030933] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 03/12/2023] [Accepted: 03/14/2023] [Indexed: 03/22/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a lethal multisystem neurodegenerative disease associated with progressive loss of motor neurons, leading to death. Not only is the clinical picture of ALS heterogenous, but also the pain sensation due to different types of pain involvement. ALS used to be considered a painless disease, but research has been emerging and depicting a more complex pain representation in ALS. Pain has been detected even a couple years before the symptomatic stage of ALS, referring to primary pain associated with muscle denervation, although secondary pain due to nociceptive causes is also a part of the clinical picture. A new non-contact dying-back injury mechanism theory of ALS recently postulated that the irreversible intrafusal proprioceptive Piezo2 microinjury could be the primary damage, with underlying genetic and environmental risk factors. Moreover, this Piezo2 primary damage is also proposed to dysregulate the primary pain pathways in the spinal dorsal horn in ALS due to the lost imbalanced subthreshold Ca2+ currents, NMDA activation and lost L-type Ca2+ currents, leading to the lost activation of wide dynamic range neurons. Our investigation is the first to show that the likely pathogenic variants of the Cav1.3 encoding CACNA1D gene may play a role in ALS pathology and the associated dysregulation or loss of the pain sensation. Furthermore, our reanalysis also shows that the SCN1A gene might also contribute to the dysregulated pain sensation in ALS. Finally, the absence of pathogenic variants of Piezo2 points toward the new non-contact dying-back injury mechanism theory of ALS. However, molecular and genetic investigations are needed to identify the functionally diverse features of this proposed novel critical pathway.
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Affiliation(s)
- Zsófia Flóra Nagy
- Department of Medical Genetics, Albert Szent-Györgyi Medical School, University of Szeged, 6725 Szeged, Hungary
| | - Balázs Sonkodi
- Department of Health Sciences and Sport Medicine, Hungarian University of Sports Science, 1123 Budapest, Hungary
| | - Margit Pál
- Department of Medical Genetics, Albert Szent-Györgyi Medical School, University of Szeged, 6725 Szeged, Hungary
- ELKH-SZTE Functional Clinical Genetics Research Group, 6720 Szeged, Hungary
| | - Péter Klivényi
- Department of Neurology, Albert Szent-Györgyi Medical School, University of Szeged, 6725 Szeged, Hungary
| | - Márta Széll
- Department of Medical Genetics, Albert Szent-Györgyi Medical School, University of Szeged, 6725 Szeged, Hungary
- ELKH-SZTE Functional Clinical Genetics Research Group, 6720 Szeged, Hungary
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10
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Sanchez V, Cohen NK, Felix E, Galor A. Factors affecting the prevalence, severity, and characteristics of ocular surface pain. EXPERT REVIEW OF OPHTHALMOLOGY 2022; 18:19-32. [PMID: 37009062 PMCID: PMC10062703 DOI: 10.1080/17469899.2023.2157813] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 12/06/2022] [Indexed: 12/13/2022]
Abstract
Introduction Ocular surface pain has been traditionally lumped under the umbrella term "dry eye" (DE) but is now understood as its own entity and can occur in the absence or presence of tear dysfunction. Identifying patients at risk for the development of chronic ocular surface pain, and factors contributing to its severity are important in providing precision medicine to patients. Areas covered In this review, we discuss factors linked to the presence and severity of ocular surface pain, including eye related features, systemic characteristics, and environmental findings. We discuss corneal nerves, whose anatomic and functional integrity can be characterized through in vivo confocal microscopy images and testing of corneal sensitivity. We review systemic diseases that are co-morbid with ocular surface pain, including physical and mental health diagnoses. Finally, we identify environmental contributors, including air pollution, previous surgeries, and medications, associated with ocular surface pain. Expert opinion Intrinsic and extrinsic factors contribute to ocular surface pain and must be considered when evaluating an individual patient. These factors can inform the suspected etiology of the pain, and guide management decisions such as tear replacement or medications targeting nerve pain.
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Affiliation(s)
- Victor Sanchez
- Department of Ophthalmology, New York University School of Medicine, 550 First Avenue, New York, NY 10016
| | - Noah K Cohen
- Bascom Palmer Eye Institute, University of Miami, 900 NW 17th Street, Miami, FL 33136
| | - Elizabeth Felix
- Bascom Palmer Eye Institute, University of Miami, 900 NW 17th Street, Miami, FL 33136
- Surgical services, Miami Veterans Administration Medical Center, 1201 NW 16th St, Miami, FL 33125
| | - Anat Galor
- Bascom Palmer Eye Institute, University of Miami, 900 NW 17th Street, Miami, FL 33136
- Surgical services, Miami Veterans Administration Medical Center, 1201 NW 16th St, Miami, FL 33125
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11
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Yoo YS, Park S, Eun P, Park YM, Lim DH, Chung TY. Corneal Neuro-Regenerative Effect of Transcutaneous Electrical Stimulation in Rabbit Lamellar Keratectomy Model. Transl Vis Sci Technol 2022; 11:17. [PMID: 36223127 PMCID: PMC9583744 DOI: 10.1167/tvst.11.10.17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose This study aimed to evaluate the effect of transcutaneous electrical stimulation (TES) on corneal nerve regeneration in rabbits injured from superficial lamellar keratectomy (SLK). Methods New Zealand White rabbits were used in this experimental study. To induce corneal nerve damage, SLK was performed using a 7.0-mm trephine. TES was applied for 28 days after the corneal nerve injury. Corneal sensitivity, Western blotting, real-time polymerase chain reaction (PCR), and immunofluorescence were performed to observe changes in the corneal tissue. Results In the 2-Hz and 20-Hz electrical stimulation groups, the degree of corneal wound healing increased by more than 10% compared to the control group, but no significant difference was observed. Conversely, the electrical stimulation (2-Hz or 20-Hz) group showed significantly increased corneal sensitivity compared to the control group. Western blot analysis revealed that small proline-rich protein 1A (SPRR1a), a regeneration-associated protein was significantly increased in the 2-Hz group on days 1 and 7 compared to that in the other groups. Once again, nerve regeneration in the 2-Hz group was supported by the results of PCR, in which a significant increase in the nerve growth factor (NGF) on day 1 was observed compared with the other groups. Moreover, immunofluorescence after 28 days of electrical stimulation showed significant nerve regeneration in the 2-Hz group. Conclusions TES promoted corneal nerve regeneration in rabbit SLK model. The application of electrical stimulation of 2-Hz frequency was more effective than the 20-Hz frequency, showing potential clinical applications for corneal diseases. Translational Relevance This study shows how application of TES to the eyes that exhibit corneal nerve damage can improve corneal nerve regeneration examined by histologic analysis.
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Affiliation(s)
- Young-Sik Yoo
- Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.,Department of Ophthalmology, College of Medicine, Uijeongbu St. Mary's Hospital, The Catholic University of Korea, Seoul, South Korea
| | - Sera Park
- Samsung Biomedical Research Institute, Seoul, South Korea
| | - Pyeonghwa Eun
- Samsung Biomedical Research Institute, Seoul, South Korea
| | - Young Min Park
- Samsung Biomedical Research Institute, Seoul, South Korea
| | - Dong Hui Lim
- Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.,Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul, South Korea
| | - Tae-Young Chung
- Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.,Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul, South Korea
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Patel S, Mittal R, Sarantopoulos KD, Galor A. Neuropathic ocular surface pain: Emerging drug targets and therapeutic implications. Expert Opin Ther Targets 2022; 26:681-695. [PMID: 36069761 PMCID: PMC9613591 DOI: 10.1080/14728222.2022.2122438] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 09/05/2022] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Dysfunction at various levels of the somatosensory system can lead to ocular surface pain with a neuropathic component. Compared to nociceptive pain (due to noxious stimuli at the ocular surface), neuropathic pain tends to be chronic and refractory to therapies, making it an important source of morbidity in the population. An understanding of the options available for neuropathic ocular surface pain, including new and emerging therapies, is thus an important topic. AREAS COVERED This review will examine studies focusing on ocular surface pain, emphasizing those examining patients with a neuropathic component. Attention will be placed toward recent (after 2017) studies that have examined new and emerging therapies for neuropathic ocular surface pain. EXPERT OPINION Several therapies have been studied thus far, and continued research is needed to identify which individuals would benefit from specific therapies. Gaps in our understanding exist, especially with availability of in-clinic diagnostics for neuropathic pain. A focus on improving diagnostic capabilities and researching gene-modulating therapies could help us to provide more specific mechanism-based therapies for patients. In the meantime, continuing to uncover new modalities and examining which are likely to work depending on pain phenotype remains an important short-term goal.
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Affiliation(s)
- Sneh Patel
- University of Miami Miller School of Medicine, Miami, FL, USA
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Rhiya Mittal
- University of Miami Miller School of Medicine, Miami, FL, USA
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Konstantinos D. Sarantopoulos
- Department of Anesthesiology, Perioperative Medicine, and Pain Management, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Anat Galor
- University of Miami Miller School of Medicine, Miami, FL, USA
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- Surgical services, Miami Veterans Affairs Medical Center, Miami, FL, USA
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Sonkodi B, Resch MD, Hortobágyi T. Is the Sex Difference a Clue to the Pathomechanism of Dry Eye Disease? Watch out for the NGF-TrkA-Piezo2 Signaling Axis and the Piezo2 Channelopathy. J Mol Neurosci 2022; 72:1598-1608. [PMID: 35507012 PMCID: PMC9374789 DOI: 10.1007/s12031-022-02015-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 04/20/2022] [Indexed: 01/11/2023]
Abstract
Dry eye disease (DED) is a multifactorial disorder with recognized pathology, but not entirely known pathomechanism. It is suggested to represent a continuum with neuropathic corneal pain with the paradox that DED is a pain-free disease in most cases, although it is regarded as a pain condition. The current paper puts into perspective that one gateway from physiology to pathophysiology could be a Piezo2 channelopathy, opening the pathway to a potentially quad-phasic non-contact injury mechanism on a multifactorial basis and with a heterogeneous clinical picture. The primary non-contact injury phase could be the pain-free microinjury of the Piezo2 ion channel at the corneal somatosensory nerve terminal. The secondary non-contact injury phase involves harsher corneal tissue damage with C-fiber contribution due to the lost or inadequate intimate cross-talk between somatosensory Piezo2 and peripheral Piezo1. The third injury phase of this non-contact injury is the neuronal sensitization process with underlying repeated re-injury of the Piezo2, leading to the proposed chronic channelopathy. Notably, sensitization may evolve in certain cases in the absence of the second injury phase. Finally, the quadric injury phase is the lingering low-grade neuroinflammation associated with aging, called inflammaging. This quadric phase could clinically initiate or augment DED, explaining why increasing age is a risk factor. We highlight the potential role of the NGF-TrkA axis as a signaling mechanism that could further promote the microinjury of the corneal Piezo2 in a stress-derived hyperexcited state. The NGF-TrkA-Piezo2 axis might explain why female sex represents a risk factor for DED.
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Affiliation(s)
- Balázs Sonkodi
- Department of Health Sciences and Sport Medicine, Hungarian University of Sports Science, Budapest, Hungary.
| | - Miklós D Resch
- Department of Ophthalmology, Semmelweis University, Budapest, Hungary
| | - Tibor Hortobágyi
- Institute of Pathology, Faculty of Medicine, University of Szeged, Szeged, Hungary.,Insitute of Psychiatry Psychology and Neuroscience, King's College London, London, UK.,Center for Age-Related Medicine, SESAM, Stavanger University Hospital, Stavanger, Norway
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Sonkodi B, Hortobágyi T. Amyotrophic lateral sclerosis and delayed onset muscle soreness in light of the impaired blink and stretch reflexes – watch out for Piezo2. Open Med (Wars) 2022; 17:397-402. [PMID: 35340618 PMCID: PMC8898040 DOI: 10.1515/med-2022-0444] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 02/02/2022] [Accepted: 02/04/2022] [Indexed: 12/13/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal, multisystem neurodegenerative disease that causes the death of motoneurons (MNs) progressively and eventually leads to paralysis. In contrast, delayed onset muscle soreness (DOMS) is defined as delayed onset soreness, muscle stiffness, loss of force-generating capacity, reduced joint range of motion, and decreased proprioceptive function. Sensory deficits and impaired proprioception are common symptoms of both ALS and DOMS, as impairment at the proprioceptive sensory terminals in the muscle spindle is theorized to occur in both. The important clinical distinction is that extraocular muscles (EOM) are relatively spared in ALS, in contrast to limb skeletal muscles; however, the blink reflex goes through a gradual impairment in a later stage of disease progression. Noteworthy is, that, the stretch of EOM induces the blink reflex. The current authors suggest that the impairment of proprioceptive sensory nerve terminals in the EOM muscle spindles are partially responsible for lower blink reflex, beyond central origin, and implies the critical role of Piezo2 ion channels and Wnt-PIP2 signaling in this pathomechanism. The proposed microinjury of Piezo2 on muscle spindle proprioceptive terminals could provide an explanation for the painless dying-back noncontact injury mechanism theory of ALS.
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Affiliation(s)
- Balázs Sonkodi
- Department of Health Sciences and Sport Medicine, University of Physical Education , Budapest , Hungary
| | - Tibor Hortobágyi
- ELKH-DE Cerebrovascular and Neurodegenerative Research Group, Department of Neurology, University of Debrecen , Debrecen , Hungary
- Department of Pathology, Faculty of Medicine, University of Szeged , Szeged , Hungary
- Department of Old Age Psychiatry, Psychology and Neuroscience, King’s College London , London , UK
- Center for Age-Related Medicine, SESAM, Stavanger University Hospital , Stavanger , Norway
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