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Nirogi R, Jayarajan P, Benade V, Abraham R, Goyal VK. Hits and misses with animal models of narcolepsy and the implications for drug discovery. Expert Opin Drug Discov 2024; 19:755-768. [PMID: 38747534 DOI: 10.1080/17460441.2024.2354293] [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: 01/13/2024] [Accepted: 05/08/2024] [Indexed: 05/22/2024]
Abstract
INTRODUCTION Narcolepsy is a chronic and rare neurological disorder characterized by disordered sleep. Based on animal models and further research in humans, the dysfunctional orexin system was identified as a contributing factor to the pathophysiology of narcolepsy. Animal models played a larger role in the discovery of some of the pharmacological agents with established benefit/risk profiles. AREAS COVERED In this review, the authors examine the phenotypes observed in animal models of narcolepsy and the characteristics of clinically used pharmacological agents in these animal models. Additionally, the authors compare the effects of clinically used pharmacological agents on the phenotypes in animal models with those observed in narcolepsy patients. EXPERT OPINION Research in canine and mouse models have linked narcolepsy to the O×R2mutation and orexin deficiency, leading to new diagnostic criteria and a drug development focus. Advancements in pharmacological therapies have significantly improved narcolepsy management, with insights from both clinical experience and from animal models having led to new treatments such as low sodium oxybate and solriamfetol. However, challenges persist in addressing symptoms beyond excessive daytime sleepiness and cataplexy, highlighting the need for further research, including the development of diurnal animal models to enhance understanding and treatment options for narcolepsy.
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Affiliation(s)
- Ramakrishna Nirogi
- Drug Discovery & Development, Suven Life Sciences Limited, Hyderabad, India
| | - Pradeep Jayarajan
- Drug Discovery & Development, Suven Life Sciences Limited, Hyderabad, India
| | - Vijay Benade
- Drug Discovery & Development, Suven Life Sciences Limited, Hyderabad, India
| | - Renny Abraham
- Drug Discovery & Development, Suven Life Sciences Limited, Hyderabad, India
| | - Vinod Kumar Goyal
- Drug Discovery & Development, Suven Life Sciences Limited, Hyderabad, India
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Valizadeh P, Momtazmanesh S, Plazzi G, Rezaei N. Connecting the dots: An updated review of the role of autoimmunity in narcolepsy and emerging immunotherapeutic approaches. Sleep Med 2024; 113:378-396. [PMID: 38128432 DOI: 10.1016/j.sleep.2023.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 12/08/2023] [Accepted: 12/09/2023] [Indexed: 12/23/2023]
Abstract
BACKGROUND Narcolepsy type 1 (NT1) is a chronic disorder characterized by pathological daytime sleepiness and cataplexy due to the disappearance of orexin immunoreactive neurons in the hypothalamus. Genetic and environmental factors point towards a potential role for inflammation and autoimmunity in the pathogenesis of the disease. This study aims to comprehensively review the latest evidence on the autoinflammatory mechanisms and immunomodulatory treatments aimed at suspected autoimmune pathways in NT1. METHODS Recent relevant literature in the field of narcolepsy, its autoimmune hypothesis, and purposed immunomodulatory treatments were reviewed. RESULTS Narcolepsy is strongly linked to specific HLA alleles and T-cell receptor polymorphisms. Furthermore, animal studies and autopsies have found infiltration of T cells in the hypothalamus, supporting T cell-mediated immunity. However, the role of autoantibodies has yet to be definitively established. Increased risk of NT1 after H1N1 infection and vaccination supports the autoimmune hypothesis, and the potential role of coronavirus disease 2019 and vaccination in triggering autoimmune neurodegeneration is a recent finding. Alterations in cytokine levels, gut microbiota, and microglial activation indicate a potential role for inflammation in the disease's development. Reports of using immunotherapies in NT1 patients are limited and inconsistent. Early treatment with IVIg, corticosteroids, plasmapheresis, and monoclonal antibodies has seldomly shown some potential benefits in some studies. CONCLUSION The current body of literature supports that narcolepsy is an autoimmune disorder most likely caused by T-cell involvement. However, the potential for immunomodulatory treatments to reverse the autoinflammatory process remains understudied. Further clinical controlled trials may provide valuable insights into this area.
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Affiliation(s)
- Parya Valizadeh
- School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Network of Immunity in Infection, Malignancy and Autoimmunity (NIIMA), Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Sara Momtazmanesh
- School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Network of Immunity in Infection, Malignancy and Autoimmunity (NIIMA), Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Giuseppe Plazzi
- IRCCS Istituto Delle Scienze Neurologiche di Bologna, Bologna, Italy; Department of Biomedical, Metabolic, and Neural Sciences, Università Degli Studi di Modena e Reggio Emilia, Modena, Italy
| | - Nima Rezaei
- Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
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Zhou M, Liu R, Tang J, Tang S. Effects of new hypnotic drugs on cognition: A systematic review and network meta-analysis. Sleep Med X 2023; 6:100094. [PMID: 38149178 PMCID: PMC10749902 DOI: 10.1016/j.sleepx.2023.100094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Revised: 11/06/2023] [Accepted: 11/08/2023] [Indexed: 12/28/2023] Open
Abstract
Background Insomnia is a common disease, and the application of various types of sleeping pills for cognitive impairment is controversial, especially as different doses can lead to different effects. Therefore, it is necessary to evaluate the cognitive impairment caused by different sleeping pills to provide a theoretical basis for guiding clinicians in the selection of medication regimens. Objective To evaluate whether various different doses (low, medium and high) of anti-insomnia drugs, such as the dual-orexin receptor antagonist (DORA), zopiclone, eszopiclone and zolpidem, induce cognitive impairment. Methods The PubMed, Embase, Scopus, Cochrane Library, and Google Scholar databases were searched from inception to September 20th, 2022 for keywords in randomized controlled trials (RCTs) to evaluate the therapeutic effects of DORA, eszopiclone, zopiclone and zolpidem on sleep and cognitive function. The primary outcomes were indicators related to cognitive characteristics, including scores on the Digit Symbol Substitution Test (DSST) and daytime alertness. The secondary outcomes were the indicators associated with sleep and adverse events. Continuous variables were expressed as the standard mean difference (SMD). Data were obtained through GetData 2.26 and analyzed by Stata v.15.0. Results A total of 8702 subjects were included in 29 studies. Eszopiclonehigh significantly increased the daytime alertness score (SMD = 3.00, 95 % CI: 1.86 to 4.13) compared with the placebo, and eszopiclonehigh significantly increased the daytime alertness score (SMD = 4.21, 95 % CI: 1.65 to 6.77; SMD = 3.95, 95 % CI: 1.38 to 6.51; SMD = 3.26, 95 % CI: 0.38 to 6.15; and SMD = 3.23, 95 % CI: 0.34 to 6.11) compared with zolpidemlow, zolpidemhigh, DORAlow, and eszopiclonemid, respectively. Compared with the placebo, zopiclone, zolpidemmid, and eszopiclonehigh, DORA significantly increased the TST (SMD = 2.39, 95 % CI: 1.11 to 3.67; SMD = 6.00, 95 % CI: 2.73 to 9.27; SMD = 1.89, 95 % CI: 0.90 to 2.88; and SMD = 1.70, 95 % CI: 0.42 to 2.99, respectively). Conclusion We recommend DORA as the best intervention for insomnia because it was highly effective in inducing and maintaining sleep without impairing cognition. Although zolpidem had a more pronounced effect on sleep maintenance, this drug is better for short-term use. Eszopiclone and zopiclone improved sleep, but their cognitive effects have yet to be verified.
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Affiliation(s)
- Mengzhen Zhou
- Department of Neurology, the First Affiliated Hospital of Shandong First Medical University, Jinan, Shandong, PR China
| | - Rujia Liu
- Department of Neurology, the First Affiliated Hospital of Shandong First Medical University, Jinan, Shandong, PR China
- Yuhuangding Hospital, No, 20, Yuhuangding East Road, Zhifu District, Yantai, Shandong, PR China
| | - Jiyou Tang
- Department of Neurology, the First Affiliated Hospital of Shandong First Medical University, Jinan, Shandong, PR China
| | - Shi Tang
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, PR China
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Zhou M, Li Y. Effect of different doses of almorexant on learning and memory in 8-month-old APP/PS1 (AD) mice. Peptides 2023; 167:171044. [PMID: 37330110 DOI: 10.1016/j.peptides.2023.171044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 06/09/2023] [Accepted: 06/09/2023] [Indexed: 06/19/2023]
Abstract
OBJECTIVE To explore the effects of different doses of almorexant (an dual orexin receptor antagonist) on learning and memory in Alzheimer's disease (AD) mice. METHODS Forty-four APP/PS1 (model of Alzheimer's disease; AD) mice were randomly divided into 4 groups: the control group (CON) and those that received 10mg/kg almorexant (low dose; LOW), 30mg/kg almorexant (medium dose; MED) and 60mg/kg almorexant (high dose; HIGH). During the 28-day intervention period, mice received an intraperitoneal injection at the beginning of the light period (6:00 am). The effects of different doses of almorexant on learning and memory and 24-hour sleep-wake behaviour were assessed by immunohistochemical staining. The above continuous variables are expressed as the mean ± standard deviation (SD), and then univariate regression analysis and generalized estimating equations were performed to compare the groups; these results are expressed as the mean difference (MD) and 95% confidence interval (CI). The statistical software used STATA 17.0 MP. RESULTS Forty-one mice completed the experiment (3 died: 2 mice in the HIGH group and 1 mouse in the CON group). Compared with the CON group, the LOW group (MD=6,803s, 95% CI: 4,470 to 9,137s), MED group (MD=14,473s, 95% CI: 12,140 to 16,806s) and the HIGH group (MD=24,505s, 95% CI: 22,052 to 26,959s) had significantly longer sleep durations. The Y maze results showed that LOW group (MD=0.14,95%CI: 0.078 to 0.20) and MED group (MD=0.14,95%CI = 0.074 to 0.20) mice compared to the CON group, and the low-medium dose of Almorexant did not damage the short-term learning and memory performance of APP / PS1 (AD) mice.Compared with the CON, LOW, and MED groups, the HIGH group exhibited a significant decrease in the Aβ plaque-positive area in the cortex (MD= -0.030, 95% CI: -0.035 to -0.025; MD=-0.049, 95% CI: -0.054 to -0.044; and MD=-0.07, 95% CI: -0.076 to -0.066, respectively). CONCLUSION The moderate dose of almorexant (30mg/kg) prolonged the sleep duration of APP/PS1 (AD) mice to a greater extent than the low dose (10mg/kg) without altering learning and memory. The MED mice showed a good sleep response and a small residual effect on the next day. High-dose (60mg / kg) almorexant impaired behavioral learning and memory performance in mice.Compared to the CON group and the LOW group, the MED group exhibited improved working memory. Thus, treatment with almorexant may reduce β-amyloid deposition in AD, slowing neurodegeneration. Additional studies are needed to determine the mechanism of action.
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Affiliation(s)
- Mengzhen Zhou
- Department of Neurology, Qianfo Mountain Hospital affiliated to Shandong First Medical University ,Jinan, Shandong, China.
| | - Yanran Li
- Department of Neurology, Qianfo Mountain Hospital affiliated to Shandong First Medical University, Jinan, Shandong, China
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Liu Z, Guan R, Pan L. TCM syndrome differentiation and treatment of narcolepsy based on neurobiological mechanism: A review. Medicine (Baltimore) 2022; 101:e32025. [PMID: 36626491 PMCID: PMC9750696 DOI: 10.1097/md.0000000000032025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Narcolepsy is a relatively rare brain disorder caused by the selective loss of orexin neurons. Narcolepsy is divided into Narcolepsy Type 1 (NT1) and Narcolepsis Type 2 (NT2). The pathogenesis of NT1 has been well established due to the severe loss of orexin neurons, while NT2 is still poorly understood, and little is known about its underlying neurobiological mechanisms. human leukocyte antigen alleles have been found to strongly influence the development of narcolepsy, with more than 90% of NT1 patients carrying the human leukocyte antigen II allele DQB1*06:02. In addition to the genetic evidence for the DQBI*06:02 allele, some other evidence suggests that a T cell-mediated immune mechanism destroys the orexin neurons of NT1, with CD4 + T cells being key. For this disease, traditional Chinese medicine (TCM) therapy has its own characteristics and advantages, especially the combination of acupuncture and medicine in the treatment of this disease in TCM, which has made considerable and gratifying progress. The purpose of this review is to introduce the frontier progress of neurobiology of narcolepsy, and to explore the syndrome differentiation and treatment of narcolepsy with the combined use of TCM and Western medicine combined with TCM.
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Affiliation(s)
- Zhao Liu
- Heilongjiang University of Traditional Chinese Medicine, Harbin, Heilongjiang Province
- * Correspondence: Zhao Liu, Heilongjiang University of Traditional Chinese Medicine, 24 Heping Road, Harbin 150006, Heilongjiang Province (e-mail:)
| | - Ruiqian Guan
- Heilongjiang University of Traditional Chinese Medicine, Harbin, Heilongjiang Province
- Second Affiliated Hospital of Heilongjiang University of Traditional Chinese Medicine, Harbin, Heilongjiang Province
| | - Limin Pan
- Heilongjiang University of Traditional Chinese Medicine, Harbin, Heilongjiang Province
- The First Affiliated Hospital of Heilongjiang University of Traditional Chinese Medicine, Harbin, Heilongjiang Province
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Pardon M, Claes P, Druwé S, Martini M, Siekierska A, Menet C, de Witte PAM, Copmans D. Modulation of sleep behavior in zebrafish larvae by pharmacological targeting of the orexin receptor. Front Pharmacol 2022; 13:1012622. [PMID: 36339591 PMCID: PMC9632972 DOI: 10.3389/fphar.2022.1012622] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 09/23/2022] [Indexed: 06/21/2024] Open
Abstract
New pharmacological approaches that target orexin receptors (OXRs) are being developed to treat sleep disorders such as insomnia and narcolepsy, with fewer side effects than existing treatments. Orexins are neuropeptides that exert excitatory effects on postsynaptic neurons via the OXRs, and are important in regulating sleep/wake states. To date, there are three FDA-approved dual orexin receptor antagonists for the treatment of insomnia, and several small molecule oral OX2R (OXR type 2) agonists are in the pipeline for addressing the orexin deficiency in narcolepsy. To find new hypnotics and psychostimulants, rodents have been the model of choice, but they are costly and have substantially different sleep patterns to humans. As an alternative model, zebrafish larvae that like humans are diurnal and show peak daytime activity and rest at night offer several potential advantages including the ability for high throughput screening. To pharmacologically validate the use of a zebrafish model in the discovery of new compounds, we aimed in this study to evaluate the functionality of a set of known small molecule OX2R agonists and antagonists on human and zebrafish OXRs and to probe their effects on the behavior of zebrafish larvae. To this end, we developed an in vitro IP-One Homogeneous Time Resolved Fluorescence (HTRF) immunoassay, and in vivo locomotor assays that record the locomotor activity of zebrafish larvae under physiological light conditions as well as under dark-light triggers. We demonstrate that the functional IP-One test is a good predictor of biological activity in vivo. Moreover, the behavioral data show that a high-throughput assay that records the locomotor activity of zebrafish throughout the evening, night and morning is able to distinguish between OXR agonists and antagonists active on the zebrafish OXR. Conversely, a locomotor assay with alternating 30 min dark-light transitions throughout the day is not able to distinguish between the two sets of compounds, indicating the importance of circadian rhythm to their pharmacological activity. Overall, the results show that a functional IP-one test in combination with a behavioral assay using zebrafish is well-suited as a discovery platform to find novel compounds that target OXRs for the treatment of sleep disorders.
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Affiliation(s)
- Marie Pardon
- Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | | | | | | | - Aleksandra Siekierska
- Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | | | - Peter A. M. de Witte
- Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Daniëlle Copmans
- Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
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Eaton SL, Murdoch F, Rzechorzek NM, Thompson G, Hartley C, Blacklock BT, Proudfoot C, Lillico SG, Tennant P, Ritchie A, Nixon J, Brennan PM, Guido S, Mitchell NL, Palmer DN, Whitelaw CBA, Cooper JD, Wishart TM. Modelling Neurological Diseases in Large Animals: Criteria for Model Selection and Clinical Assessment. Cells 2022; 11:cells11172641. [PMID: 36078049 PMCID: PMC9454934 DOI: 10.3390/cells11172641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 08/19/2022] [Accepted: 08/22/2022] [Indexed: 11/16/2022] Open
Abstract
Issue: The impact of neurological disorders is recognised globally, with one in six people affected in their lifetime and few treatments to slow or halt disease progression. This is due in part to the increasing ageing population, and is confounded by the high failure rate of translation from rodent-derived therapeutics to clinically effective human neurological interventions. Improved translation is demonstrated using higher order mammals with more complex/comparable neuroanatomy. These animals effectually span this translational disparity and increase confidence in factors including routes of administration/dosing and ability to scale, such that potential therapeutics will have successful outcomes when moving to patients. Coupled with advancements in genetic engineering to produce genetically tailored models, livestock are increasingly being used to bridge this translational gap. Approach: In order to aid in standardising characterisation of such models, we provide comprehensive neurological assessment protocols designed to inform on neuroanatomical dysfunction and/or lesion(s) for large animal species. We also describe the applicability of these exams in different large animals to help provide a better understanding of the practicalities of cross species neurological disease modelling. Recommendation: We would encourage the use of these assessments as a reference framework to help standardise neurological clinical scoring of large animal models.
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Affiliation(s)
- Samantha L. Eaton
- Royal (Dick) School of Veterinary Studies and Roslin Institute, University of Edinburgh, Easter Bush Campus, Roslin, Midlothian EH25 9RG, UK
- Correspondence: (S.L.E.); (T.M.W.); Tel.: +44-(0)-131-651-9125 (S.L.E.); +44-(0)-131-651-9233 (T.M.W.)
| | - Fraser Murdoch
- Royal (Dick) School of Veterinary Studies and Roslin Institute, University of Edinburgh, Easter Bush Campus, Roslin, Midlothian EH25 9RG, UK
| | - Nina M. Rzechorzek
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Gerard Thompson
- Centre for Clinical Brain Sciences, University of Edinburgh, Chancellor’s Building, 49 Little France Crescent, Edinburgh EH16 4SB, UK
- Department of Clinical Neurosciences, NHS Lothian, 50 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - Claudia Hartley
- Royal (Dick) School of Veterinary Studies and Roslin Institute, University of Edinburgh, Easter Bush Campus, Roslin, Midlothian EH25 9RG, UK
| | - Benjamin Thomas Blacklock
- Royal (Dick) School of Veterinary Studies and Roslin Institute, University of Edinburgh, Easter Bush Campus, Roslin, Midlothian EH25 9RG, UK
| | - Chris Proudfoot
- The Large Animal Research & Imaging Facility, Royal (Dick) School of Veterinary Studies and Roslin Institute, University of Edinburgh, Easter Bush Campus, Roslin, Midlothian EH25 9RG, UK
| | - Simon G. Lillico
- Royal (Dick) School of Veterinary Studies and Roslin Institute, University of Edinburgh, Easter Bush Campus, Roslin, Midlothian EH25 9RG, UK
| | - Peter Tennant
- The Large Animal Research & Imaging Facility, Royal (Dick) School of Veterinary Studies and Roslin Institute, University of Edinburgh, Easter Bush Campus, Roslin, Midlothian EH25 9RG, UK
| | - Adrian Ritchie
- The Large Animal Research & Imaging Facility, Royal (Dick) School of Veterinary Studies and Roslin Institute, University of Edinburgh, Easter Bush Campus, Roslin, Midlothian EH25 9RG, UK
| | - James Nixon
- The Large Animal Research & Imaging Facility, Royal (Dick) School of Veterinary Studies and Roslin Institute, University of Edinburgh, Easter Bush Campus, Roslin, Midlothian EH25 9RG, UK
| | - Paul M. Brennan
- Translational Neurosurgery, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Stefano Guido
- Royal (Dick) School of Veterinary Studies and Roslin Institute, University of Edinburgh, Easter Bush Campus, Roslin, Midlothian EH25 9RG, UK
- Bioresearch & Veterinary Services, University of Edinburgh, Chancellor’s Building, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Nadia L. Mitchell
- Faculty of Agriculture and Life Sciences, Lincoln University, P.O. Box 85084, Lincoln 7647, New Zealand
| | - David N. Palmer
- Faculty of Agriculture and Life Sciences, Lincoln University, P.O. Box 85084, Lincoln 7647, New Zealand
| | - C. Bruce A. Whitelaw
- Royal (Dick) School of Veterinary Studies and Roslin Institute, University of Edinburgh, Easter Bush Campus, Roslin, Midlothian EH25 9RG, UK
| | - Jonathan D. Cooper
- Departments of Pediatrics, Genetics, and Neurology, Washington University School of Medicine in St. Louis, 660 S Euclid Ave, St. Louis, MO 63110, USA
| | - Thomas M. Wishart
- Royal (Dick) School of Veterinary Studies and Roslin Institute, University of Edinburgh, Easter Bush Campus, Roslin, Midlothian EH25 9RG, UK
- Correspondence: (S.L.E.); (T.M.W.); Tel.: +44-(0)-131-651-9125 (S.L.E.); +44-(0)-131-651-9233 (T.M.W.)
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Sun Y, Tisdale R, Park S, Ma SC, Heu J, Haire M, Allocca G, Yamanaka A, Morairty SR, Kilduff TS. The development of sleep/wake disruption and cataplexy as hypocretin/orexin neurons degenerate in male vs. female Orexin/tTA; TetO-DTA Mice. Sleep 2022; 45:6532492. [PMID: 35182424 PMCID: PMC9742901 DOI: 10.1093/sleep/zsac039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 12/23/2021] [Indexed: 01/10/2023] Open
Abstract
Narcolepsy Type 1 (NT1), a sleep disorder with similar prevalence in both sexes, is thought to be due to loss of the hypocretin/orexin (Hcrt) neurons. Several transgenic strains have been created to model this disorder and are increasingly being used for preclinical drug development and basic science studies, yet most studies have solely used male mice. We compared the development of narcoleptic symptomatology in male vs. female orexin-tTA; TetO-DTA mice, a model in which Hcrt neuron degeneration can be initiated by removal of doxycycline (DOX) from the diet. EEG, EMG, subcutaneous temperature, gross motor activity, and video recordings were conducted for 24-h at baseline and 1, 2, 4, and 6 weeks after DOX removal. Female DTA mice exhibited cataplexy, the pathognomonic symptom of NT1, by Week 1 in the DOX(-) condition but cataplexy was not consistently present in males until Week 2. By Week 2, both sexes showed an impaired ability to sustain long wake bouts during the active period, the murine equivalent of excessive daytime sleepiness in NT1. Subcutaneous temperature appeared to be regulated at lower levels in both sexes as the Hcrt neurons degenerated. During degeneration, both sexes also exhibited the "Delta State", characterized by sudden cessation of activity, high delta activity in the EEG, maintenance of muscle tone and posture, and the absence of phasic EMG activity. Since the phenotypes of the two sexes were indistinguishable by Week 6, we conclude that both sexes can be safely combined in future studies to reduce cost and animal use.
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Affiliation(s)
- Yu Sun
- Biosciences Division, SRI International, Menlo Park, CA, USA
| | | | | | - Shun-Chieh Ma
- Biosciences Division, SRI International, Menlo Park, CA, USA
| | - Jasmine Heu
- Biosciences Division, SRI International, Menlo Park, CA, USA
| | - Meghan Haire
- Biosciences Division, SRI International, Menlo Park, CA, USA
| | | | - Akihiro Yamanaka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Japan,Department of Neural Regulation, Nagoya University Graduate School of Medicine, Japan
| | | | - Thomas S Kilduff
- Corresponding author. Thomas S. Kilduff, Center for Neuroscience, Biosciences Division SRI International, 333 Ravenswood Ave Menlo Park, CA 94025 USA.
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Barateau L, Jaussent I, Roeser J, Ciardiello C, Kilduff TS, Dauvilliers Y. Cerebrospinal fluid monoamine levels in central disorders of hypersomnolence. Sleep 2021; 44:zsab012. [PMID: 33476396 PMCID: PMC8271127 DOI: 10.1093/sleep/zsab012] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 12/17/2020] [Indexed: 12/21/2022] Open
Abstract
STUDY OBJECTIVES Whether the cause of daytime sleepiness in narcolepsy type 1 (NT1) is a direct consequence of the loss of orexin (ORX) neurons or whether low orexin reduces the efficacy of the monoaminergic systems to promote wakefulness is unclear. The neurobiology underlying sleepiness in other central hypersomnolence disorders, narcolepsy type 2 (NT2), and idiopathic hypersomnia (IH), is currently unknown. METHODS Eleven biogenic amines including the monoaminergic neurotransmitters and their metabolites and five trace amines were measured in the cerebrospinal fluid (CSF) of 94 drug-free subjects evaluated at the French National Reference Center for Narcolepsy: 39 NT1(orexin-deficient) patients, 31 patients with objective sleepiness non orexin-deficient (NT2 and IH), and 24 patients without objective sleepiness. RESULTS Three trace amines were undetectable in the sample: tryptamine, octopamine, and 3-iodothyronamine. No significant differences were found among the three groups for quantified monoamines and their metabolites in crude and adjusted models; however, CSF 5-hydroxyindoleacetic acid (5-HIAA) levels tended to increase in NT1 compared to other patients after adjustment. Most of the biomarkers were not associated with ORX-A levels, clinical or neurophysiological parameters, but a few biomarkers (e.g. 3-methoxy-4-hydroxyphenylglycol and norepinephrine) correlated with daytime sleepiness and high rapid eye movement (REM) sleep propensity. CONCLUSIONS We found no striking differences among CSF monoamines, their metabolites and trace amine levels, and few associations between them and key clinical or neurophysiological parameters in NT1, NT2/IH, and patients without objective sleepiness. Although mostly negative, these findings are a significant contribution to our understanding of the neurobiology of hypersomnolence in these disorders that remain mysterious and deserve further exploration.
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Affiliation(s)
- Lucie Barateau
- Sleep–Wake Disorders Unit, Department of Neurology, Gui-de-Chauliac Hospital, CHU Montpellier, University of Montpellier, Montpellier, France
- National Reference Network for Narcolepsy, CHU Montpellier, Montpellier, France
- INM, University of Montpellier, INSERM, Montpellier, France
| | | | - Julien Roeser
- Charles River Laboratories, South San Francisco, San Francisco, CA, USA
| | | | - Thomas S Kilduff
- Center for Neuroscience, Biosciences Division, SRI International, Menlo Park, CA, USA
| | - Yves Dauvilliers
- Sleep–Wake Disorders Unit, Department of Neurology, Gui-de-Chauliac Hospital, CHU Montpellier, University of Montpellier, Montpellier, France
- National Reference Network for Narcolepsy, CHU Montpellier, Montpellier, France
- INM, University of Montpellier, INSERM, Montpellier, France
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Sleep Disorders in dogs: A Pathophysiological and Clinical Review. Top Companion Anim Med 2021; 43:100516. [PMID: 33556640 DOI: 10.1016/j.tcam.2021.100516] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 01/22/2021] [Accepted: 01/29/2021] [Indexed: 12/11/2022]
Abstract
Sleep is a fundamental process in mammals, including domestic dogs. Disturbances in sleep affect physiological functions like cognitive and physical performance, immune response, pain sensation and increase the risk of diseases. In dogs, sleep can be affected by several conditions, with narcolepsy, REM sleep behavior disorder and sleep breathing disorders being the most frequent causes. Furthermore, sleep disturbances can be a symptom of other primary diseases where they can contribute to the worsening of clinical signs. This review describes reciprocally interacting sleep and wakefulness promoting systems and how their dysfunction can explain the pathophysiological mechanisms of sleep disorders. Additionally, this work discusses the clinical characteristics, diagnostic tools and available treatments for these disorders while highlighting areas in where further studies are needed so as to improve their treatment and prevention.
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