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Koo BB, Abdelfattah A, Eysa A, Lu L. The Melanocortin and Endorphin Neuropeptides in Patients with Restless Legs Syndrome. Ann Neurol 2024; 95:688-699. [PMID: 38308537 DOI: 10.1002/ana.26876] [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: 08/07/2023] [Revised: 11/13/2023] [Accepted: 01/10/2024] [Indexed: 02/04/2024]
Abstract
OBJECTIVE Based upon similarities between the urge to move and sensory discomfort of restless legs syndrome (RLS) and properties of melanocortin hormones, including their incitement of movement and hyperalgesia, we assessed plasma and cerebrospinal fluid (CSF) α-melanocyte-stimulating hormone (α-MSH) and β-endorphin in RLS patients and controls. METHODS Forty-two untreated moderate-to-severe RLS patients and 44 matched controls underwent venipuncture at 19:00, 20:30, and 22:00; 37 RLS and 36 controls had lumbar puncture at 21:30. CSF and plasma were analyzed for pro-opiomelanocortin (POMC), adrenocorticotropin hormone (ACTH), α-MSH, β-MSH, and β-endorphin by immunoassay. RLS severity was assessed by International RLS Study Group Severity Scale. RESULTS RLS participants were 52.7 ± 12.0 years old, 61.9% were women, 21.4% had painful RLS, and RLS severity was 24.8 ± 9.0. Controls had similar age and sex. Plasma ACTH, α-MSH, and β-endorphin were similar between groups. Plasma POMC was significantly greater in RLS than controls (17.0 ± 11.5 vs 12.7 ± 6.1fmol/ml, p = 0.048). CSF ACTH was similar between groups. CSF β-MSH was significantly higher in painful than nonpainful RLS or controls (48.2 ± 24.8 vs 32.1 ± 14.8 vs 32.6 ± 15.2pg/ml, analysis of variance [ANOVA] p = 0.03). CSF α-MSH was higher in RLS than controls (34.2 ± 40.9 vs 20.3 ± 11.0pg/ml, p = 0.062). CSF β-EDP was lowest in painful RLS, intermediate in nonpainful RLS, and highest in controls (8.0 ± 3.4 vs 10.8 ± 3.1 vs 12.3 ± 5.0pg/ml, ANOVA p = 0.049). The ratio of the sum of CSF α- and β-MSH to CSF β-endorphin was highest, intermediate, and lowest in painful RLS, nonpainful RLS, and controls (p = 0.007). INTERPRETATION CSF β-MSH is increased and CSF β-endorphin decreased in RLS patients with painful symptoms. ANN NEUROL 2024;95:688-699.
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Affiliation(s)
- Brian B Koo
- Department of Neurology, Yale University, New Haven, CT, USA
| | | | - Athar Eysa
- Department of Internal Medicine, Morristown Medical Center, Morristown, NJ, USA
| | - Lingeng Lu
- Department of Chronic Disease Epidemiology, Yale University, New Haven, CT, USA
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Chen PY, Lin SY, Wu CS, Hung SH, Chen DHK, Liu WT, Lin YC. An expedited model for identifying potential patients with periodic leg movements. J Sleep Res 2024:e14198. [PMID: 38500205 DOI: 10.1111/jsr.14198] [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: 10/01/2023] [Revised: 02/19/2024] [Accepted: 03/05/2024] [Indexed: 03/20/2024]
Abstract
Periodic leg movements during sleep (PLMS) may have crucial consequences in adults. This study aimed to identify baseline characteristics, symptoms, or questionnaires that could help to identify sleep-disordered breathing patients with significant PLMS. Patients aged 20-80 years who underwent polysomnography for assessing sleep disturbance were included. Various factors such as sex, age, body measurements, symptoms, apnea-hypopnea index (AHI), and sleep quality scales were analysed to determine the presence of PLMS. The study included 1480 patients with a mean age of 46.4 ± 13.4 years, among whom 110 (7.4%) had significant PLMS with a PLM index of 15 or higher. There were no significant differences observed in terms of sex or BMI between patients with and without significant PLMS. However, the odds ratios (OR) for PLMS were 4.33, 4.41, and 4.23 in patients who were aged over 50 years, had insomnia, or had an ESS score of less than 10, respectively. Notably, the OR increased up to 67.89 times in patients who presented with all three risk factors. Our analysis identified significant risk factors for PLMS: age over 50, self-reported insomnia, and lower daytime sleepiness levels. These findings aid in identifying potential PLMS patients, facilitating confirmatory examinations and managing associated comorbidities.
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Affiliation(s)
- Po-Yueh Chen
- Department of Otolaryngology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
- Department of Otolaryngology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Shang-Yang Lin
- Center for Artificial Intelligence and Advanced Robotics, National Taiwan University, Taipei, Taiwan
| | - Chung-Sheng Wu
- Department of Primary Care Medicine, Shuang-Ho Hospital, Taipei Medical University, New Taipei City, Taiwan
| | - Shih-Han Hung
- Department of Otolaryngology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
- Department of Otolaryngology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- International Master/Ph.D. Program in Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - David Hsin-Kuang Chen
- Department of Medical Education, Shuang-Ho Hospital, Taipei Medical University, New Taipei City, Taiwan
| | - Wen-Te Liu
- Department of Chest Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan
- Sleep Center, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan
| | - Yi-Chih Lin
- Department of Otolaryngology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Sleep Center, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan
- Department of Otolaryngology, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan
- School of Public Health, College of Public Health, Taipei Medical University, Taipei, Taiwan
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3
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Shen Z, Yang X, She T, Zhao G, Dou Z, Luo Y, Lin W, Dang W, Yu S. Deficits in brain default mode network connectivity mediate the relationship between poor sleep quality and anxiety severity. Sleep 2024; 47:zsad296. [PMID: 37988563 DOI: 10.1093/sleep/zsad296] [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: 06/28/2023] [Revised: 11/03/2023] [Indexed: 11/23/2023] Open
Abstract
STUDY OBJECTIVES Chronic insomnia disorder (CID) is a prevalent sleep disorder that frequently cooccurs with anxiety. The association between insomnia and anxiety has been established; however, the neurobiological basis of this relationship remains unclear. This study aimed to investigate the neural markers of CID patients with and without anxiety and to determine whether specific neural connectivity mediates the relationship between insomnia and anxiety. METHODS This study included 180 participants, comprising CID patients with anxiety (CID-A), CID patients without anxiety (CID-NA), and good sleep controls. All participants completed self-reported measures of sleep quality and anxiety severity and underwent functional magnetic resonance imaging. Brain functional integration was measured using functional connectivity density (FCD) and resting-state functional connectivity (rsFC). Correlation and mediation analyses were used to examine the relationships among brain connectivity, sleep quality, and anxiety severity. RESULTS The CID-NA and CID-A groups showed decreased local FCD in the medial prefrontal cortex (mPFC) and disrupted rsFC between the precuneus and other brain regions. Only the CID-A group exhibited altered long-range FCD in the precuneus and the rsFC between the anterior default mode network (DMN, e.g. mPFC) and posterior DMN (e.g. precuneus). Mediation analysis revealed DMN dysconnectivity underlying the association between poor sleep quality and anxiety symptoms. CONCLUSIONS This study identified shared and distinct brain circuit disruptions in the CID-NA and CID-A groups, with deficits in DMN connectivity as a potential neural mechanism through which disrupted sleep augments anxiety. These findings may facilitate the development of personalized therapies for insomnia and associated anxiety problems.
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Affiliation(s)
- Zhifu Shen
- School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Department of Traditional Chinese Medicine, The Affiliated Hospital of North Sichuan Medical College, Nanchong, China
- Department of Traditional Chinese and Western Medicine, North Sichuan Medical College, Nanchong, China
| | - Xue Yang
- Department of Laboratory Medicine, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Tianwei She
- Department of Traditional Chinese and Western Medicine, North Sichuan Medical College, Nanchong, China
| | - Guangli Zhao
- School of Rehabilitation and Health Preservation, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Zeyang Dou
- School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Yucai Luo
- School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Wenting Lin
- School of Rehabilitation and Health Preservation, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Wantai Dang
- Department of Rheumatology and Immunology, The First Affiliated Hospital of Chengdu Medical College, Chengdu, China
| | - Siyi Yu
- School of Acupuncture and Tuina, Chengdu University of Traditional Chinese Medicine, Chengdu, China
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Ferré S, Winkelman JW, García-Borreguero D, Belcher AM, Chang JH, Earley CJ. Restless legs syndrome, neuroleptic-induced akathisia, and opioid-withdrawal restlessness: shared neuronal mechanisms? Sleep 2024; 47:zsad273. [PMID: 37864837 PMCID: PMC10925952 DOI: 10.1093/sleep/zsad273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 09/27/2023] [Indexed: 10/23/2023] Open
Abstract
Restlessness is a core symptom underlying restless legs syndrome (RLS), neuroleptic-induced akathisia, and opioid withdrawal. These three conditions also share other clinical components suggesting some overlap in their pathophysiology. Recent prospective studies demonstrate the frequent incidence of RLS-like symptoms during opioid withdrawal and supervised prescription opioid tapering. Based on the therapeutic role of µ-opioid receptor (MOR) agonists in the three clinical conditions and recent preclinical experimental data in rodents, we provide a coherent and unifying neurobiological basis for the restlessness observed in these three clinical syndromes and propose a heuristic hypothesis of a key role of the specific striatal neurons that express MORs in akathisia/restlessness.
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Affiliation(s)
- Sergi Ferré
- Integrative Neurobiology Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
| | - John W Winkelman
- Departments of Psychiatry and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | | | - Annabelle M Belcher
- Division of Addiction, Research, and Treatment, Department of Psychiatry, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Joy H Chang
- Substance Abuse Consultation Service, Department of Psychiatry, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Christopher J Earley
- Department of Neurology and Sleep Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Zhang J, Zhang J, Sun H, Yang J, Ma Y, Chen K, Su J, Yu X, Yang F, Zhang Z, Zhao T, Hu X, Zhai Y, Liu Q, Wang J, Liu C, Wang Z. Cerebellum drives functional dysfunctions in restless leg syndrome. Sleep Med 2023; 110:172-178. [PMID: 37595434 DOI: 10.1016/j.sleep.2023.08.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 07/04/2023] [Accepted: 08/14/2023] [Indexed: 08/20/2023]
Abstract
OBJECTIVE Restless legs syndrome (RLS) has serious effects on patients' sleep quality, physical and mental health. However, the pathophysiological mechanisms of RLS remain unclear. This study utilized both static and dynamic functional activity and connectivity analyses approaches as well as effective connectivity analysis to reveal the neurophysiological basis of RLS. METHODS The resting-state functional MRI (rs-fMRI) data from 32 patients with RLS and 33 age-, and gender-matched healthy control (HC) were collected. Dynamic and static amplitude of low frequency fluctuation (ALFF), functional connectivity (FC), and Granger causality analysis (GCA) were employed to reveal the abnormal functional activities and couplings in patients with RLS. RESULTS RLS patients showed over-activities in left parahippocampus and right cerebellum, hyper-connectivities of right cerebellum with left basal ganglia, left postcentral gyrus and right precentral gyrus, and enhanced effective connectivity from right cerebellum to left postcentral gyrus compared to HC. CONCLUSIONS Abnormal cerebellum-basal ganglia-sensorimotor cortex circuit may be the underlying neuropathological basis of RLS. Our findings highlight the important role of right cerebellum in the onset of RLS and suggest right cerebellum may be a potential target for precision therapy.
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Affiliation(s)
- Jiang Zhang
- College of Electrical Engineering, Sichuan University, Chengdu, China; Med-X Center for Informatics, Sichuan University, Chengdu, China
| | - Jingyue Zhang
- College of Electrical Engineering, Sichuan University, Chengdu, China
| | - Hui Sun
- College of Electrical Engineering, Sichuan University, Chengdu, China
| | - Jia Yang
- State Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, China; Yunnan Key Laboratory of Primate Biomedical Research, Kunming, Yunnan, China
| | - Yingzi Ma
- State Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, China; Yunnan Key Laboratory of Primate Biomedical Research, Kunming, Yunnan, China
| | - Kexuan Chen
- Medical School, Kunming University of Science and Technology, Kunming, China
| | - Jing Su
- State Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, China; Yunnan Key Laboratory of Primate Biomedical Research, Kunming, Yunnan, China
| | - Xiaohui Yu
- State Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, China; Yunnan Key Laboratory of Primate Biomedical Research, Kunming, Yunnan, China
| | - Futing Yang
- State Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, China; Yunnan Key Laboratory of Primate Biomedical Research, Kunming, Yunnan, China
| | - Zhiwei Zhang
- College of Electrical Engineering, Sichuan University, Chengdu, China
| | - Tianyu Zhao
- College of Electrical Engineering, Sichuan University, Chengdu, China
| | - Xiuying Hu
- Med-X Center for Informatics, Sichuan University, Chengdu, China; Innovation Center of Nursing Research, Nursing Key Laboratory of Sichuan Province, West China Hospital, Sichuan University, Chengdu, China
| | - Yiran Zhai
- College of Electrical Engineering, Sichuan University, Chengdu, China; Med-X Center for Informatics, Sichuan University, Chengdu, China
| | - Qihong Liu
- College of Biomedical Engineering, Sichuan University, Chengdu, China
| | - Jiaojian Wang
- State Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, China; Yunnan Key Laboratory of Primate Biomedical Research, Kunming, Yunnan, China.
| | - Chunyan Liu
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China; Beijing Key Laboratory of Neuromodulation, Beijing, China.
| | - Zhengbo Wang
- State Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, China; Yunnan Key Laboratory of Primate Biomedical Research, Kunming, Yunnan, China.
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6
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Kim TJ, Kim MH, Kim JH, Jun JS, Byun JI, Sunwoo JS, Shin JW, Gho SM, Sohn CH, Jung KY. Change of iron content in brain regions after intravenous iron therapy in restless legs syndrome: quantitative susceptibility mapping study. Sleep 2023; 46:zsad154. [PMID: 37257418 DOI: 10.1093/sleep/zsad154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 05/22/2023] [Indexed: 06/02/2023] Open
Abstract
STUDY OBJECTIVES The pathomechanism of restless legs syndrome (RLS) is related to brain iron deficiency and iron therapy is effective for RLS; however, the effect of iron therapy on human brain iron state has never been studied with magnetic resonance imaging. This study aimed to investigate the change of brain iron concentrations in patients with RLS after intravenous iron therapy using quantitative susceptibility mapping (QSM). METHODS We enrolled 31 RLS patients and 20 healthy controls. All participants underwent initial baseline (t0) assessment using brain magnetic resonance imaging, serum iron status, and sleep questionnaires including international RLS Study Group rating scale (IRLS). RLS patients underwent follow-up tests at 6 and 24 weeks (t1 and t2) after receiving 1000 mg ferric carboxymaltose. Iron content of region-of-interest on QSM images was measured for 13 neural substrates using the fixed-shaped method. RESULTS RLS symptoms evaluated using IRLS were significantly improved after iron treatment (t0: 29.7 ± 6.5, t1: 19.5 ± 8.5, t2: 21.3 ± 10.1; p < .001). There was no significant difference in susceptibility values between the controls and RLS patients at t0. In the caudate nucleus, putamen, and pulvinar thalamus of RLS patients, the QSM values differed significantly for three timepoints (p = .035, .048, and .032, respectively). The post-hoc analysis revealed that the QSM values increased at t1 in the caudate nucleus (66.8 ± 18.0 vs 76.4 ± 16.6, p = .037) and decreased from t1 to t2 in the putamen (69.4 ± 16.3 vs 62.5 ± 13.6, p = .025). Changes in the QSM values for the pulvinar and caudate nuclei at t1 were positively and negatively correlated with symptomatic improvement, respectively (r = 0.361 and -0.466, respectively). CONCLUSIONS Intravenous iron treatment results in changes in brain iron content which correlate to reductions in RLS severity. This suggests a connection between symptom improvement and the associated specific brain regions constituting the sensorimotor network.
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Affiliation(s)
- Tae-Joon Kim
- Department of Neurology, Ajou University School of Medicine, Suwon, Republic of Korea
- Department of Neurology, Ajou University Hospital, Suwon, Republic of Korea
| | - Min Hye Kim
- Department of Neurology, Ajou University Hospital, Suwon, Republic of Korea
| | - Jung Hwan Kim
- Department of Neurology, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Jin-Sun Jun
- Department of Neurology, Kangnam Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Republic of Korea
| | - Jung-Ick Byun
- Department of Neurology, Kyung Hee University Hospital at Gangdong, Seoul, Republic of Korea
| | - Jun-Sang Sunwoo
- Department of Neurology, Kangbuk Samsung Hospital, Seoul, Republic of Korea
| | - Jung-Won Shin
- Department of Neurology, CHA Bundang Medical Center, CHA University, Seongnam, Republic of Korea
| | - Sung-Min Gho
- MR Clinical Solutions & Research Collaborations, GE Healthcare, Seoul, Republic of Korea
| | - Chul-Ho Sohn
- Department of Radiology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea
| | - Ki-Young Jung
- Department of Neurology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea
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Carnell S, Steele KE, Thapaliya G, Kuwubara H, Aghababian A, Papantoni A, Nandi A, Brašić JR, Moran TH, Wong DF. Milkshake Acutely Stimulates Dopamine Release in Ventral and Dorsal Striatum in Healthy-Weight Individuals and Patients with Severe Obesity Undergoing Bariatric Surgery: A Pilot Study. Nutrients 2023; 15:2671. [PMID: 37375579 DOI: 10.3390/nu15122671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 05/31/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
The overconsumption of palatable energy-dense foods drives obesity, but few human studies have investigated dopamine (DA) release in response to the consumption of a palatable meal, a putative mediator of excess intake in obesity. We imaged [11C]raclopride in the brain with positron emission tomography (PET) to assess striatal dopamine (DA) receptor binding pre- and post-consumption of a highly palatable milkshake (250 mL, 420 kcal) in 11 females, 6 of whom had severe obesity, and 5 of whom had healthy-weight. Those with severe obesity underwent assessments pre- and 3 months post-vertical sleeve gastrectomy (VSG). Our results demonstrated decreased post- vs. pre-meal DA receptor binding in the ventral striatum (p = 0.032), posterior putamen (p = 0.012), and anterior caudate (p = 0.018), consistent with meal-stimulated DA release. Analysis of each group separately suggested that results in the caudate and putamen were disproportionately driven by meal-associated changes in the healthy-weight group. Baseline (pre-meal) DA receptor binding was lower in severe obesity than in the healthy-weight group. Baseline DA receptor binding and DA release did not change from pre- to post-surgery. The results of this small pilot study suggest that milkshake acutely stimulates DA release in the ventral and dorsal striatum. This phenomenon likely contributes to the overconsumption of highly palatable foods in the modern environment.
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Affiliation(s)
- Susan Carnell
- Division of Child and Adolescent Psychiatry, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Kimberley E Steele
- Johns Hopkins Center for Bariatric Surgery, Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA
| | - Gita Thapaliya
- Division of Child and Adolescent Psychiatry, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Hiroto Kuwubara
- Section of High Resolution Brain Positron Emission Tomography Imaging, Division of Nuclear Medicine and Molecular Imaging, The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Anahys Aghababian
- Division of Child and Adolescent Psychiatry, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Afroditi Papantoni
- Division of Child and Adolescent Psychiatry, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Ayon Nandi
- Section of High Resolution Brain Positron Emission Tomography Imaging, Division of Nuclear Medicine and Molecular Imaging, The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - James R Brašić
- Section of High Resolution Brain Positron Emission Tomography Imaging, Division of Nuclear Medicine and Molecular Imaging, The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Timothy H Moran
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Dean F Wong
- Mallinckrodt Institute of Radiology, Departments of Radiology, Psychiatry, Neurology, Neuroscience, Washington University in St. Louis School of Medicine, St. Louis, MO 63110, USA
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Zhang H, Sun H, Li J, Fan Y, Jülich ST, Lei X. Subtypes of insomnia revealed by the heterogeneity of neuroanatomical patterns: a structural MRI study. Biol Psychol 2023; 180:108591. [PMID: 37230291 DOI: 10.1016/j.biopsycho.2023.108591] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 05/17/2023] [Accepted: 05/22/2023] [Indexed: 05/27/2023]
Abstract
The current conflicting neuroimaging findings of insomnia disorder (ID) may be attributed to heterogeneity in ID. The present study aims to clarify the high heterogeneity in ID and examine the objective neurobiological subtypes of ID by using a novel machine learning method based on gray matter volumes (GMVs). We recruited 56 patients with ID and 73 healthy controls (HCs). The T1-weighted anatomical images were obtained for each participant. We investigated whether the ID has higher interindividual heterogeneity in GMVs. Then, we used a heterogeneous machine learning algorithm by discriminative analysis (HYDRA) to identify subtypes of ID with features of brain regional GMVs. We found that patients with ID have higher interindividual variability than HCs. HYDRA identified two distinct and reliable neuroanatomical subtypes of ID. Two subtypes showed significantly different aberrance in GMVs compared with HCs. Specifically, subtype 1 exhibited widespread decreased GMVs in some brain regions, including the right inferior temporal gyrus, left superior temporal gyrus, left precuneus, right middle cingulate, and right supplementary motor area. Subtype 2 only demonstrated increased GMVs in the right superior temporal gyrus. Additionally, the GMVs of altered brain regions in subtype 1 were significantly correlated with daytime functioning, but in subtype 2, they were significantly correlated with sleep disturbance. These results explain conflicting neuroimaging findings and propose a potential objective neurobiological classification contributing to ID's precise clinical diagnosis and treatment. DATA AND CODE AVAILABILITY: The source and means of obtaining the data used in the study have been described fully in the Methods and Materials section. The codes and data in this study are available upon a reasonable request to the corresponding author.
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Affiliation(s)
- Haobo Zhang
- Sleep and NeuroImaging Center, Faculty of Psychology, Southwest University, Chongqing, 400715, China; Key Laboratory of Cognition and Personality (Southwest University), Ministry of Education, Chongqing, 400715, China
| | - Haonan Sun
- Sleep and NeuroImaging Center, Faculty of Psychology, Southwest University, Chongqing, 400715, China; Key Laboratory of Cognition and Personality (Southwest University), Ministry of Education, Chongqing, 400715, China
| | - Jiaqi Li
- Sleep and NeuroImaging Center, Faculty of Psychology, Southwest University, Chongqing, 400715, China; Key Laboratory of Cognition and Personality (Southwest University), Ministry of Education, Chongqing, 400715, China
| | - Yuhan Fan
- Sleep and NeuroImaging Center, Faculty of Psychology, Southwest University, Chongqing, 400715, China; Key Laboratory of Cognition and Personality (Southwest University), Ministry of Education, Chongqing, 400715, China
| | - Simon Theodor Jülich
- Sleep and NeuroImaging Center, Faculty of Psychology, Southwest University, Chongqing, 400715, China; Key Laboratory of Cognition and Personality (Southwest University), Ministry of Education, Chongqing, 400715, China
| | - Xu Lei
- Sleep and NeuroImaging Center, Faculty of Psychology, Southwest University, Chongqing, 400715, China; Key Laboratory of Cognition and Personality (Southwest University), Ministry of Education, Chongqing, 400715, China.
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9
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Silvani A, Ghorayeb I, Manconi M, Li Y, Clemens S. Putative Animal Models of Restless Legs Syndrome: A Systematic Review and Evaluation of Their Face and Construct Validity. Neurotherapeutics 2023; 20:154-178. [PMID: 36536233 PMCID: PMC10119375 DOI: 10.1007/s13311-022-01334-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/02/2022] [Indexed: 12/24/2022] Open
Abstract
Restless legs syndrome (RLS) is a sensorimotor disorder that severely affects sleep. It is characterized by an urge to move the legs, which is often accompanied by periodic limb movements during sleep. RLS has a high prevalence in the population and is usually a life-long condition. While its origins remain unclear, RLS is initially highly responsive to treatment with dopaminergic agonists that target D2-like receptors, in particular D2 and D3, but the long-term response is often unsatisfactory. Over the years, several putative animal models for RLS have been developed, mainly based on the epidemiological and neurochemical link with iron deficiency, treatment efficacy of D2-like dopaminergic agonists, or genome-wide association studies that identified risk factors in the patient population. Here, we present the first systematic review of putative animal models of RLS, provide information about their face and construct validity, and report their role in deciphering the underlying pathophysiological mechanisms that may cause or contribute to RLS. We propose that identifying the causal links between genetic risk factors, altered organ functions, and changes to molecular pathways in neural circuitry will eventually lead to more effective new treatment options that bypass the side effects of the currently used therapeutics in RLS, especially for long-term therapy.
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Affiliation(s)
- Alessandro Silvani
- Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum - University of Bologna, Ravenna Campus, Ravenna, Italy
| | - Imad Ghorayeb
- Département de Neurophysiologie Clinique, Pôle Neurosciences Cliniques, CHU de Bordeaux, Bordeaux, France
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, Université de Bordeaux, Bordeaux, France
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, CNRS, Bordeaux, France
| | - Mauro Manconi
- Sleep Medicine Unit, Neurocenter of Southern Switzerland, EOC, Ospedale Civico, Lugano, Switzerland
- Department of Neurology, University Hospital, Inselspital, Bern, Switzerland
- Faculty of Biomedical Sciences, Università della Svizzera Italiana, Lugano, Switzerland
| | - Yuqing Li
- Department of Neurology, College of Medicine, Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, USA
| | - Stefan Clemens
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, USA.
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10
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Earley CJ, Jones BC, Ferré S. Brain-iron deficiency models of restless legs syndrome. Exp Neurol 2022; 356:114158. [PMID: 35779614 PMCID: PMC9357217 DOI: 10.1016/j.expneurol.2022.114158] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 06/24/2022] [Accepted: 06/25/2022] [Indexed: 11/04/2022]
Abstract
Restless legs syndrome (RLS) is a common sensorimotor disorder for which two main pathological elements are fairly well accepted: Brain iron deficiency (BID) and an altered dopaminergic system. The ability to better understand the causal and consequential factors related to these two pathological elements, would hopefully lead to the development of better therapeutic strategies for treating, if not curing, this disease. The current understanding of the relationship between these two elements is that BID leads to some alterations in neurotransmitters and subsequent changes in the dopaminergic system. Therefore, rodent models based on diet-induced BID, provide a biological substrate to understand the consequences of BID on dopaminergic pathway and on alternative pathways that may be involved. In this review, we present the current research on dopaminergic changes found in RLS subjects and compare that to what is seen in the BID rodent model to provide a validation of the BID rodent model. We also demonstrate the ability of the BID model to predict changes in other neurotransmitter systems and how that has led to new treatment options. Finally, we will present arguments for the utility of recombinant inbred mouse strains that demonstrate natural variation in brain iron, to explore the genetic basis of altered brain iron homeostasis as a model to understand why in idiopathic RLS there can exist a BID despite normal peripheral iron store. This review is the first to draw on 25 years of human and basic research into the pathophysiology of RLS to provide strong supportive data as to the validity of BID model as an important translational model of the disease. As we will demonstrate here, not only does the BID model closely and accurately mimic what we see in the dopaminergic system of RLS, it is the first model to identify alternative systems from which new treatments have recently been developed.
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Affiliation(s)
- Christopher J Earley
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Byron C Jones
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Sergi Ferré
- Integrative Neurobiology Section, National Institutes of Health/National Institute on Drug Abuse, Baltimore, MD, USA
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11
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Salminen AV, Clemens S, García-Borreguero D, Ghorayeb I, Li Y, Manconi M, Ondo W, Rye D, Siegel JM, Silvani A, Winkelman JW, Allen RP, Ferré S. Consensus guidelines on the construct validity of rodent models of restless legs syndrome. Dis Model Mech 2022; 15:dmm049615. [PMID: 35946581 PMCID: PMC9393041 DOI: 10.1242/dmm.049615] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 07/10/2022] [Indexed: 12/16/2022] Open
Abstract
Our understanding of the causes and natural course of restless legs syndrome (RLS) is incomplete. The lack of objective diagnostic biomarkers remains a challenge for clinical research and for the development of valid animal models. As a task force of preclinical and clinical scientists, we have previously defined face validity parameters for rodent models of RLS. In this article, we establish new guidelines for the construct validity of RLS rodent models. To do so, we first determined and agreed on the risk, and triggering factors and pathophysiological mechanisms that influence RLS expressivity. We then selected 20 items considered to have sufficient support in the literature, which we grouped by sex and genetic factors, iron-related mechanisms, electrophysiological mechanisms, dopaminergic mechanisms, exposure to medications active in the central nervous system, and others. These factors and biological mechanisms were then translated into rodent bioequivalents deemed to be most appropriate for a rodent model of RLS. We also identified parameters by which to assess and quantify these bioequivalents. Investigating these factors, both individually and in combination, will help to identify their specific roles in the expression of rodent RLS-like phenotypes, which should provide significant translational implications for the diagnosis and treatment of RLS.
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Affiliation(s)
- Aaro V. Salminen
- Institute of Neurogenomics, Helmholtz Zentrum München GmbH - German Research Center for Environmental Health, 85764 Neuherberg, Germany
- Institute of Human Genetics, Klinikum rechts der Isar, Technische Universität München, 81675 Munich, Germany
| | - Stefan Clemens
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA
| | | | - Imad Ghorayeb
- Département de Neurophysiologie Clinique, Pôle Neurosciences Cliniques, CHU de Bordeaux, 33076 Bordeaux, France
- Université de Bordeaux, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, 33076 Bordeaux, France
- CNRS, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, 33076 Bordeaux, France
| | - Yuqing Li
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Mauro Manconi
- Sleep Medicine Unit, Regional Hospital of Lugano, Neurocenter of Southern Switzerland, 6900 Lugano, Switzerland
- Faculty of Biomedical Sciences, Università della Svizzera Italiana, 6900 Lugano, Switzerland
- Department of Neurology, University Hospital Inselspital, 3010 Bern, Switzerland
| | - William Ondo
- Houston Methodist Hospital Neurological Institute, Weill Cornell Medical School, Houston, TX 77070, USA
| | - David Rye
- Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Jerome M. Siegel
- Neuropsychiatric Institute and Brain Research Institute, University of California, Los Angeles, CA 90095, USA
- Neurobiology Research, Veterans Administration Greater Los Angeles Healthcare System, North Hills, CA 91343, USA
| | - Alessandro Silvani
- Department of Biomedical and Neuromotor Sciences Alma Mater Studiorum, Università di Bologna, 48121 Ravenna Campus, Ravenna, Italy
| | - John W. Winkelman
- Departments of Psychiatry and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Richard P. Allen
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21224, USA
| | - Sergi Ferré
- Integrative Neurobiology Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
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12
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Lai YY, Hsieh KC, Chew KT, Nguyen D, Siegel JM. Striatal mechanism of the restless legs syndrome. Sleep 2022; 45:6583453. [PMID: 35537196 PMCID: PMC9272194 DOI: 10.1093/sleep/zsac110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 04/28/2022] [Indexed: 11/14/2022] Open
Abstract
Abstract
Study Objectives
Brain iron deficiency has been reported to be associated with the restless legs syndrome (RLS). However, 30%–50% of RLS patients do not respond to iron therapy, indicating that mechanisms other than brain iron deficiency may also participate in this disease. The striatum is known to be involved in the modulation of motor activity. We speculated that dysfunction of the striatum may induce RLS.
Methods
Two groups, wild-type (WT) and iron-deficient (ID) rats were used. Each group was divided into two subgroups, control and N-methyl-d-aspartate striatal-lesioned. After baseline recording, striatal-lesioned wild-type (WT-STL) and striatal-lesioned iron-deficient (ID-STL) rats were given pramipexole and thioperamide injections. Iron-deficient and ID-STL rats were then given a standard rodent diet for 4 weeks, and their sleep and motor activity were recorded.
Results
WT-STL rats showed periodic leg movements (PLM) in wake, an increase in PLM in slow wave sleep (SWS), a decrease in rapid-eye-movement sleep, and a decrease in the daily average duration of episodes in SWS. The sleep–wake pattern and motor activity did not differ between ID and ID-STL rats. Thioperamide or pramipexole injection decreased PLM in sleep and in wake in WT-STL rats and ID-STL rats. Unlike ID rats, whose motor hyperactivity can be reversed by iron replacement, PLM in wake and in sleep in ID-STL rats were not fully corrected by iron treatment.
Conclusions
Lesions of the striatum generate RLS-like activity in rats. Dysfunction of the striatum may be responsible for failure to respond to iron treatment in some human RLS patients.
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Affiliation(s)
- Yuan-Yang Lai
- Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, University of California , Los Angeles, CA , USA
- VA Greater Los Angeles HealthCare System , Sepulveda, 16111 Plummer Street, North Hills, CA , USA
- Greater Los Angeles Veterans Research and Education Foundation , 11301 Wilshire Blvd, Los Angeles, CA , USA
| | - Kung-Chiao Hsieh
- VA Greater Los Angeles HealthCare System , Sepulveda, 16111 Plummer Street, North Hills, CA , USA
| | - Keng-Tee Chew
- VA Greater Los Angeles HealthCare System , Sepulveda, 16111 Plummer Street, North Hills, CA , USA
| | - Darian Nguyen
- Greater Los Angeles Veterans Research and Education Foundation , 11301 Wilshire Blvd, Los Angeles, CA , USA
| | - Jerome M Siegel
- Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, University of California , Los Angeles, CA , USA
- VA Greater Los Angeles HealthCare System , Sepulveda, 16111 Plummer Street, North Hills, CA , USA
- Brain Research Institute, University of California, Los Angeles , CA , USA
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13
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Baba C, Ozdogar AT, Ozcelik S, Kaya E, Ozakbas S. Relationship between presence of spinal cord lesion and restless legs syndrome in multiple sclerosis. Somatosens Mot Res 2022; 39:116-120. [PMID: 35042439 DOI: 10.1080/08990220.2022.2027360] [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: 12/15/2022]
Abstract
BACKGROUND Even though the prevalence of restless leg syndrome in multiple sclerosis (MS) is known to vary between 12.5% and 60%, the underlying pathophysiological mechanism remains unclear. AIM This study aims to investigate the relationship between spinal cord lesions and restless leg syndrome in MS. MATERIALS AND METHODS In total, 959 persons with MS were enrolled in this study. Demographic and clinical data of persons with MS were recorded by interviewing and medical records. Neurologists blind to the presence of restless leg syndrome evaluated MRI scans for the presence of demyelinating lesions in the brainstem and spinal cord. RESULTS The restless leg syndrome was detected in 222 participants (23.15%). Restless leg syndrome was not significantly linked to mean age, body mass index, gender, and MS duration, but persons with MS with restless leg syndrome have a higher disability level (p = 0.044). In addition, no difference in the brainstem and thoracic cord was found between persons with MS with and without restless leg syndrome, while there is a significant relationship between the presence of cervical cord lesion and restless leg syndrome. CONCLUSION Higher disability scores and characteristics of lesion patterns in the spinal cord could explain higher rates of restless leg syndrome in persons with MS. Considering the negative effects of restless leg syndrome, the increased awareness and treatment of restless leg syndrome among persons with MS is essential for better managing.
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Affiliation(s)
- Cavid Baba
- Graduate School of Health Sciences, Dokuz Eylul University, Izmir, Turkey
| | - Asiye Tuba Ozdogar
- Graduate School of Health Sciences, Dokuz Eylul University, Izmir, Turkey
| | - Sinem Ozcelik
- Department of Neurology, Faculty of Medicine, Dokuz Eylul University, Izmir, Turkey
| | - Ergi Kaya
- Department of Neurology, Faculty of Medicine, Dokuz Eylul University, Izmir, Turkey
| | - Serkan Ozakbas
- Department of Neurology, Faculty of Medicine, Dokuz Eylul University, Izmir, Turkey
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14
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Wang XX, Feng Y, Tan EK, Ondo WG, Wu YC. Stroke-related restless legs syndrome: epidemiology, clinical characteristics and pathophysiology. Sleep Med 2022; 90:238-248. [DOI: 10.1016/j.sleep.2022.02.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 01/23/2022] [Accepted: 02/01/2022] [Indexed: 12/24/2022]
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15
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Abstract
Restless Legs Syndrome (RLS) is a sensorimotor disorder that severely affects sleep. It is characterized by an urge to move the legs that is often accompanied by periodic limb movements during sleep (PLMS). RLS has a high prevalence in the population and is usually a life-long condition. While its origins remain unclear, RLS is initially highly responsive to treatment with dopaminergics that target the D3 receptor. However, over time patients often develop a gradual tolerance that can lead to the emergence of adverse effects and the augmentation of the symptoms. While the basal ganglia and the striatum control leg movements, the lumbar spinal cord is the gateway for the sensory processing of the symptoms and critical for the associated leg movements. D3 receptors are highly expressed in nucleus accumbens (NAc) of the striatum and the sensory-processing areas of the spinal dorsal horn. In contrast, D1 receptors are strongly expressed throughout the entire striatum and in the ventral horn of the spinal cord. Long-term treatment with D3 receptor full agonists is associated with an upregulation of the D1 receptor subtype, and D3 and D1 receptors can form functional heteromers, in which the D3R controls the D1R function. It is conceivable that the switch from beneficial treatment to augmentation observed in RLS patients after prolonged D3R agonist exposure may be the result of unmasked D1-like receptor actions.
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Affiliation(s)
- Stefan Clemens
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, USA.
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16
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Franco B, Mota DS, Daubian-Nosé P, Rodrigues NDA, Simino LADP, de Fante T, Bezerra RMN, Manchado Gobatto FDB, Manconi M, Torsoni AS, Esteves AM. Iron deficiency in pregnancy: Influence on sleep, behavior, and molecular markers of adult male offspring. J Neurosci Res 2021; 99:3325-3338. [PMID: 34651324 DOI: 10.1002/jnr.24968] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 08/17/2021] [Accepted: 08/31/2021] [Indexed: 12/14/2022]
Abstract
Iron restriction during pregnancy can lead to iron deficiency and changes in the dopaminergic system in the adulthood of offspring, and restless legs syndrome (RLS) is closely related to these changes. Objectives: Analyze whether iron restriction during pregnancy would cause changes in the behavior, sleep, and dopaminergic system of the male offspring. In addition, we aimed to assess whether exercise would be able to modulate these variables. The pregnant rats (Wistar) were divided into four groups with different concentrations of iron in the diet: standard (St), supplementation (Su), restriction since weaning (R1), and restriction only during pregnancy (R2). After birth, the offspring were assigned to their respective groups according to the dams diet (St, Su, R1, and R2) and distributed into sedentary (SD) and exercised (EX) (for 8 weeks of training), reaching eight groups of offspring (O): OSt SD, OSt EX, OSu SD, OSu EX, OR1 SD, OR1 EX, OR2 SD, and OR2 EX. Sleep, behavior, and analysis of key genes of dopaminergic system (D2, DAT) were performed after 8 weeks. The results for trained offspring that the mother received supplementation diet were the most expressive, with increased freezing and the OR1 SD group showed an increase in DAT protein content. These changes may have been due to the association between the dams diet during pregnancy and the practice of exercise by the offspring. The different concentrations of iron during pregnancy caused changes in the offspring, however, they were not associated with fetal programming in the context of RLS.
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Affiliation(s)
- Beatriz Franco
- Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Campinas, Brazil
| | - Diego Silva Mota
- Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Limeira, Brazil
| | - Paulo Daubian-Nosé
- Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Limeira, Brazil
| | | | | | - Thaís de Fante
- Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Limeira, Brazil
| | | | - Fúlvia de Barros Manchado Gobatto
- Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Campinas, Brazil.,Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Limeira, Brazil
| | - Mauro Manconi
- Sleep and Epilepsy Center, Neurocenter of Southern Switzerland, Civic Hospital of Lugano (EOC), Lugano, Switzerland
| | | | - Andrea Maculano Esteves
- Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Campinas, Brazil.,Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Limeira, Brazil
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17
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Moser U, Schwab J. Restless arm syndrome: a rare disease? BMJ Case Rep 2021; 14:e244890. [PMID: 34544716 PMCID: PMC8454428 DOI: 10.1136/bcr-2021-244890] [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] [Accepted: 08/31/2021] [Indexed: 11/03/2022] Open
Abstract
Restless legs syndrome (RLS) is a common neurological disorder characterised by an irresistible urge to move the lower limbs, often accompanied by unpleasant sensations in the legs, typically occurring in the evening and at night and improving with movement. Restless arms syndrome (RAS) predominantly affects the arms, while the legs are rarely affected. RAS appears to be very rare, with very few cases described to date, but the diagnosis of RAS is probably made too infrequently, especially for milder and transient forms. The patient reported here even had severe symptoms for years that could have indicated RAS. He observed an immediate improvement in all RAS-related symptoms after administration of 100 mg L-dopa +25 mg benserazide, which continues to this day. Clinicians should always be alert for RLS-like symptoms in one or both arms that worsen at rest and improve with movement, thinking of possible RAS.
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Affiliation(s)
- Ulrich Moser
- Bayerische Ärztekammer München, D-81677 München, Bavaria, Germany
| | - Jasmin Schwab
- Bayerische Ärztekammer München, D-81677 München, Bavaria, Germany
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18
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Sathiavageesan S, Annamalai I, Malayappan A, Melchizedek K, Ramajayam R, Annadurai A. Restless leg syndrome presenting as chronic severe limb pain in a dialysis patient. Hemodial Int 2021; 26:E1-E4. [PMID: 34396677 DOI: 10.1111/hdi.12978] [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: 06/20/2021] [Revised: 07/29/2021] [Accepted: 07/30/2021] [Indexed: 11/28/2022]
Abstract
"Chronic pain" is a commonly reported symptom among hemodialysis patients. Despite its high prevalence and the poor health-related quality of life associated with it, chronic pain remains an ineffectively assessed and managed entity in dialysis patients. We report a case of a 55-year-old gentleman on maintenance hemodialysis who presented with 3 months history of "excruciating flitting and fleeting type" of pain largely involving both lower limbs and occasionally neck, shoulder, chest, and upper limbs. The pain was so intolerable that it even triggered suicidal intentions in the patient. Common causes of chronic pain in dialysis patients were considered, but the initial history and clinical examination remained elusive. The patient was empirically started on oral analgesics, benzodiazepines, calcitriol, and levocarnitine supplementation but had no significant effect on his symptoms. A comprehensive repeat clinical history revealed the nocturnal periodicity of symptoms, specific aggravation of pain with inactivity, and its temporary relief with movement. This helped us narrow down the diagnosis to restless leg syndrome (RLS) amidst the myriad causes of chronic pain in dialysis patients. The "constant urge to move the legs" which is the defining characteristic of RLS was inconspicuous in our patient and excruciating pain was the predominant manifestation. This atypical presentation of RLS with agonizing pain involving multiple sites of the body led to a delay in the diagnosis and initiation of appropriate therapeutic measures. The patient had a dramatic response to therapy with dopamine agonists and withdrawal of the drug led to reappearance of his symptoms which further confirmed the diagnosis of RLS. RLS should be considered in the evaluation of chronic pain in dialysis patients and renal health care providers should familiarize themselves with the varied atypical, forme fruste manifestations of RLS to avoid diagnostic delay of this disabling but treatable condition.
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Affiliation(s)
- Subrahmanian Sathiavageesan
- Department of Nephrology, Trichy SRM Medical College Hospital and Research Centre, Trichy, Tamil Nadu, India.,Department of Nephrology, Sundaram Hospital, Trichy, Tamil Nadu, India
| | - Ishwarya Annamalai
- Department of Nephrology, Trichy SRM Medical College Hospital and Research Centre, Trichy, Tamil Nadu, India
| | - Arunkarki Malayappan
- Department of Medicine, Trichy SRM Medical College Hospital and Research Centre, Trichy, Tamil Nadu, India
| | - Kamalanathan Melchizedek
- Department of Nephrology, Trichy SRM Medical College Hospital and Research Centre, Trichy, Tamil Nadu, India
| | - Ranjitha Ramajayam
- Department of Nephrology, Trichy SRM Medical College Hospital and Research Centre, Trichy, Tamil Nadu, India
| | - Anjali Annadurai
- Department of Nephrology, Trichy SRM Medical College Hospital and Research Centre, Trichy, Tamil Nadu, India
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19
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Zhang R, Manza P, Tomasi D, Kim SW, Shokri-Kojori E, Demiral SB, Kroll DS, Feldman DE, McPherson KL, Biesecker CL, Wang GJ, Volkow ND. Dopamine D1 and D2 receptors are distinctly associated with rest-activity rhythms and drug reward. J Clin Invest 2021; 131:e149722. [PMID: 34264865 DOI: 10.1172/jci149722] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 07/14/2021] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Certain components of rest-activity rhythms such as greater eveningness (delayed phase), physical inactivity (blunted amplitude) and shift work (irregularity) are associated with increased risk for drug use. Dopaminergic (DA) signaling has been hypothesized to mediate the associations, though clinical evidence is lacking. METHODS We examined associations between rhythm components and striatal D1 (D1R) and D2/3 receptor (D2/3R) availability in 32 healthy adults (12 female, age: 42.40±12.22) and its relationship to drug reward. Rest-activity rhythms were assessed by one-week actigraphy combined with self-reports. [11C]NNC112 and [11C]raclopride Positron Emission Tomography (PET) scans were conducted to measure D1R and D2/3R availability, respectively. Additionally, self-reported drug-rewarding effects of 60 mg oral methylphenidate were assessed. RESULTS We found that delayed rhythm was associated with higher D1R availability in caudate, which was not attributable to sleep loss or 'social jet lag', whereas physical inactivity was associated with higher D2/3R availability in nucleus accumbens (NAc). Delayed rest-activity rhythm, higher caudate D1R and NAc D2/3R availability were associated with greater sensitivity to the rewarding effects of methylphenidate. CONCLUSION These findings reveal specific components of rest-activity rhythms associated with striatal D1R, D2/3R availability and drug-rewarding effects. Personalized interventions that target rest-activity rhythms may help prevent and treat substance use disorders. TRIAL REGISTRATION ClinicalTrials.gov: NCT03190954FUNDING. This work was accomplished with support from the National Institute on Alcohol Abuse and Alcoholism (ZIAAA000550).
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Affiliation(s)
- Rui Zhang
- National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, United States of America
| | - Peter Manza
- National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, United States of America
| | - Dardo Tomasi
- National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, United States of America
| | - Sung Won Kim
- National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, United States of America
| | - Ehsan Shokri-Kojori
- National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, United States of America
| | - Sukru B Demiral
- National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, United States of America
| | - Danielle S Kroll
- National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, United States of America
| | - Dana E Feldman
- National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, United States of America
| | - Katherine L McPherson
- National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, United States of America
| | - Catherine L Biesecker
- National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, United States of America
| | - Gene-Jack Wang
- National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, United States of America
| | - Nora D Volkow
- National Institute on Drug Abuse, NIH, Bethesda, United States of America
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20
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Ferré S, Guitart X, Quiroz C, Rea W, García-Malo C, Garcia-Borreguero D, Allen RP, Earley CJ. Akathisia and Restless Legs Syndrome: Solving the Dopaminergic Paradox. Sleep Med Clin 2021; 16:249-267. [PMID: 33985651 DOI: 10.1016/j.jsmc.2021.02.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Akathisia is an urgent need to move that is associated with treatment with dopamine receptor blocking agents (DRBAs) and with restless legs syndrome (RLS). The pathogenetic mechanism of akathisia has not been resolved. This article proposes that it involves an increased presynaptic dopaminergic transmission in the ventral striatum and concomitant strong activation of postsynaptic dopamine D1 receptors, which form complexes (heteromers) with dopamine D3 and adenosine A1 receptors. It also proposes that in DRBA-induced akathisia, increased dopamine release depends on inactivation of autoreceptors, whereas in RLS it depends on a brain iron deficiency-induced down-regulation of striatal presynaptic A1 receptors.
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Affiliation(s)
- Sergi Ferré
- Integrative Neurobiology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Triad Building, 333 Cassell Drive, Baltimore, MD 21224, USA.
| | - Xavier Guitart
- Integrative Neurobiology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Triad Building, 333 Cassell Drive, Baltimore, MD 21224, USA
| | - César Quiroz
- Integrative Neurobiology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Triad Building, 333 Cassell Drive, Baltimore, MD 21224, USA
| | - William Rea
- Integrative Neurobiology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Triad Building, 333 Cassell Drive, Baltimore, MD 21224, USA
| | - Celia García-Malo
- Sleep Research Institute, Paseo de la Habana 151, Madrid 28036, Spain
| | | | - Richard P Allen
- Department of Neurology, Johns Hopkins University, Johns Hopkins Bayview Medical Center, 5501 Hopkins Bayview Circle, Baltimore, MD 21224, USA
| | - Christopher J Earley
- Department of Neurology, Johns Hopkins University, Johns Hopkins Bayview Medical Center, 5501 Hopkins Bayview Circle, Baltimore, MD 21224, USA
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21
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Abstract
Restless legs syndrome (RLS) is a chronic sensorimotor disorder characterized by an urge to move the legs. This urge is often accompanied by pain or other uncomfortable and unpleasant sensations, it either occurs or worsens during rest, particularly in the evening and/or at night, and temporarily improves with activity. Affecting nearly 3% of the North American and European populations in its moderate-to-severe form, RLS has a considerable negative impact on the quality of life, and sleep and is associated with significant morbidity. Although new developments have deepened our understanding of the disorder, yet, the corresponding pathophysiologic features that underlie the sensorimotor presentation are still not fully understood. Usually, symptoms respond well to dopamine agonists (DA), anticonvulsants, or opiates, used either alone or in any combination, but still, a subset of patients remains refractory to medical therapy and serious side effects such as augmentation and impulse control disorder may occur in patients with RLS under DA. Convincing treatment alternative are lacking but recently patients' spontaneous reports of a remarkable and total remission of RLS symptoms following cannabis use has been reported. The antinociceptive effect of marijuana has been documented in many painful neurological conditions and the potential benefit of cannabis use in patients with refractory RLS should, therefore, be questioned by robust clinical trials. Here, we review basic knowledge of RLS and the putative mechanisms by which cannabis may exert its analgesic effects.
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Gossard TR, Trotti LM, Videnovic A, St Louis EK. Restless Legs Syndrome: Contemporary Diagnosis and Treatment. Neurotherapeutics 2021; 18:140-155. [PMID: 33880737 PMCID: PMC8116476 DOI: 10.1007/s13311-021-01019-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/28/2021] [Indexed: 12/12/2022] Open
Abstract
Restless legs syndrome (RLS) is characterized by an uncomfortable urge to move the legs while at rest, relief upon movement or getting up to walk, and worsened symptom severity at night. RLS may be primary (idiopathic) or secondary to pregnancy or a variety of systemic disorders, especially iron deficiency, and chronic renal insufficiency. Genetic predisposition with a family history is common. The pathogenesis of RLS remains unclear but is likely to involve central nervous system dopaminergic dysfunction, as well as other, undefined contributing mechanisms. Evaluation begins with a thorough history and examination, and iron measures, including ferritin and transferrin saturation, should be checked at presentation and with worsened symptoms, especially when augmentation develops. Augmentation is characterized by more intense symptom severity, earlier symptom occurrence, and often, symptom spread from the legs to the arms or other body regions. Some people with RLS have adequate symptom control with non-pharmacological measures such as massage or temperate baths. First-line management options include iron-replacement therapy in those with evidence for reduced body-iron stores or, alternatively, with prescribed gabapentin or pregabalin, and dopamine agonists such as pramipexole, ropinirole, and rotigotine. Second-line therapies include intravenous iron infusion in those who are intolerant of oral iron and/or those having augmentation with intense, severe RLS symptoms, and opioids including tramadol, oxycodone, and methadone. RLS significantly impacts patients' quality of life and remains a therapeutic area sorely in need of innovation and a further pipeline of new, biologically informed therapies.
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Affiliation(s)
- Thomas R Gossard
- Mayo Center for Sleep Medicine, 200 First Street SW, Rochester, MN, 55905, USA
| | | | | | - Erik K St Louis
- Mayo Center for Sleep Medicine, 200 First Street SW, Rochester, MN, 55905, USA.
- Departments of Neurology and Clinical and Translational Research, Mayo Clinic Southwest Wisconsin, La Crosse, Wisconsin, USA.
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Emamian F, Mahdipour M, Noori K, Rostampour M, Mousavi SB, Khazaie H, Khodaie-Ardakani M, Tahmasian M, Zarei M. Alterations of Subcortical Brain Structures in Paradoxical and Psychophysiological Insomnia Disorder. Front Psychiatry 2021; 12:661286. [PMID: 34025484 PMCID: PMC8139557 DOI: 10.3389/fpsyt.2021.661286] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 04/07/2021] [Indexed: 12/29/2022] Open
Abstract
Insomnia disorder (ID) is a common illness associated with mood and cognitive impairments. Subtyping ID is an ongoing debate in sleep medicine, but the underlying mechanisms of each subtype is poorly understood. Growing evidence suggests that subcortical brain structures play the key roles in pathophysiology of ID and its subtypes. Here, we aimed to investigate structural alteration of subcortical regions in patients with two common ID subtypes i.e., paradoxical and psychophysiological insomnia. Fifty-five patients and 49 healthy controls were recruited for this study and T1-weighted images and subjective and objective sleep parameters (i.e., Pittsburgh Sleep Quality Index and polysomnography) were collected from participants. Subcortical structures including the hippocampus, amygdala, caudate, putamen, globus pallidus, nucleus accumbens, and thalamus were automatically segmented in FSL. Volume and shape (using surface vertices) of each structure were compared between the groups, controlled for covariates, and corrected for multiple comparisons. In addition, correlations of sleep parameters and surface vertices or volumes were calculated. The caudate's volume was smaller in patients than controls. Compared with controls, we found regional shrinkage in the caudate, nucleus accumbens, posterior putamen, hippocampus, thalamus, and amygdala in paradoxical insomnia and shrinkage in the amygdala, caudate, hippocampus, and putamen in psychophysiological insomnia. Interestingly, comparing two patients groups, shape alteration in the caudate, putamen, and nucleus accumbens in paradoxical insomnia and shrinkage in the thalamus, amygdala, and hippocampus in psychophysiological insomnia were observed. Both subjective and objective sleep parameters were associated with these regional shape alterations in patients. Our results support the differential role of subcortical brain structures in pathophysiology of paradoxical and psychophysiological insomnia.
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Affiliation(s)
- Farnoosh Emamian
- Department of Psychiatry, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.,Sleep Disorders Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Mostafa Mahdipour
- Institute of Medical Science and Technology, Shahid Beheshti University, Tehran, Iran
| | - Khadijeh Noori
- Sleep Disorders Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Masoumeh Rostampour
- Sleep Disorders Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - S Bentolhoda Mousavi
- Psychosis Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Habibolah Khazaie
- Sleep Disorders Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | | | - Masoud Tahmasian
- Institute of Medical Science and Technology, Shahid Beheshti University, Tehran, Iran
| | - Mojtaba Zarei
- Institute of Medical Science and Technology, Shahid Beheshti University, Tehran, Iran
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Roy A, Earley CJ, Allen RP, Kaminsky ZA. Developing a biomarker for restless leg syndrome using genome wide DNA methylation data. Sleep Med 2020; 78:120-127. [PMID: 33422814 DOI: 10.1016/j.sleep.2020.12.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 12/14/2020] [Accepted: 12/16/2020] [Indexed: 12/31/2022]
Abstract
This study reports on an epigenetic biomarker for restless leg syndrome (RLS) developed using whole genome DNA methylation data. Lymphocyte-derived DNA methylation was examined in 15 subjects with and without RLS (discovery cohort). T-tests and linear regressions were used followed by a principal component analysis (PCA). The principal component model from the discovery cohort was used to predict RLS status in a peripheral blood (N = 24; including 12 cases and 12 controls) and a post-mortem neural tissue (N = 71; including 36 cases and 35 controls) replication cohort as well as iron deficiency anemia status in a publicly available dataset (N = 71, 59 cases with iron deficiency anemia, 12 controls). Using receiver-operating characteristic analysis the optimum biomarker model - that included 49 probes - predicted RLS status in the blood-based replication cohort with an area under the curve (AUC) of 87.5% (confidence interval = 71.9%-100%). In the neural tissue samples, the model predicted RLS status with an AUC of 73.4% (confidence interval = 61.5%-85.3%). An AUC of 83% was found for predictions of iron deficiency anemia. Thus, the blood-based biomarker model reported here and built with epigenome-wide data showed reasonable replicability in lymphocytes and neural tissue samples. A limitation of this study is that we could not determine the metabolic or neurobiological pathways linking epigenetic changes with RLS. Further research is needed to fine-tune this model for prospective predictions of RLS and to enable translation for clinical use.
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Affiliation(s)
- Arunima Roy
- The Royal's Institute of Mental Health Research, University of Ottawa, Canada
| | - Christopher J Earley
- Department of Neurology, The Johns Hopkins University School of Medicine, 5501 Hopkins Bayview Circle, Baltimore, MD, 21209, USA
| | - Richard P Allen
- Department of Neurology, The Johns Hopkins University School of Medicine, 5501 Hopkins Bayview Circle, Baltimore, MD, 21209, USA
| | - Zachary A Kaminsky
- The Royal's Institute of Mental Health Research, University of Ottawa, Canada; Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa Ontario Canada; Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Mental Health, Bloomberg School of Public Health, Baltimore, MD, USA.
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25
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Akhmadulina AO, Levin OS, Poluektov MG. [Restless legs syndrome in Parkinson's disease]. Zh Nevrol Psikhiatr Im S S Korsakova 2020; 120:80-88. [PMID: 33205935 DOI: 10.17116/jnevro202012010280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Disturbances in sleep and wakefulness are important symptoms of Parkinson's disease (PD) and are associated with negative effects on patients' quality of life. The analysis of literature on the relationship between RLS and PD revealed three main hypotheses explaining the relatively high incidence of RLS in PD: (1) RLS can be considered as an early (prodromal) manifestation or a predictor of PD that can outpace its main symptoms by several years (by analogy with conduct disorder during sleep with REM); (2) the high incidence of RLS in the advanced stage of PD may be associated with augmentation of previously latent RLS symptoms during prolonged dopaminergic therapy of PD; (3) a significant proportion of RLS cases in PD patients are not «classical» RLS, but represent, for example, manifestations of motor or non-motor fluctuations or a special form of stereotypy in the legs. Further research is needed to determine if any of these statements are true.
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Affiliation(s)
- A O Akhmadulina
- Russian Medical Academy of Continuous Professional Education, Moscow, Russia
| | - O S Levin
- Russian Medical Academy of Continuous Professional Education, Moscow, Russia
| | - M G Poluektov
- Sechenov First Moscow Medical University, Moscow, Russia
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Kocar TD, Müller HP, Kassubek J. Differential functional connectivity in thalamic and dopaminergic pathways in restless legs syndrome: a meta-analysis. Ther Adv Neurol Disord 2020; 13:1756286420941670. [PMID: 32821291 PMCID: PMC7412904 DOI: 10.1177/1756286420941670] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 06/22/2020] [Indexed: 12/13/2022] Open
Abstract
Objective: Restless legs syndrome (RLS) is a sensorimotor disorder with alterations in somatosensory processing in association with a dysfunctional cerebral network, involving the basal ganglia, limbic network, and sensorimotor pathways. Resting state functional magnetic resonance imaging (MRI) is a powerful tool to provide in vivo insight into functional processing and as such is of special interest in RLS considering the widespread pattern of networks involved in this disorder. In this meta-analysis of resting state functional MRI studies, we analyzed the preponderance of functional connectivity changes associated with RLS and discussed possible links to sensorimotor dysfunction and somatosensory processing. Methods: A systematic research using the online library PubMed was conducted and a total of seven studies passed the inclusion criteria of the meta-analysis. The results of these studies were merged and a statistical probability map was generated that indicated the likelihood of functional connectivity changes within the combined cohort, both for increased and decreased connectivity. Results: The meta-analysis demonstrated decreased functional connectivity within the dopaminergic network in participants with RLS compared with healthy controls, including the nigrostriatal, mesolimbic, and mesocortical pathways. Increased functional connectivity was observed bilaterally in the thalamus, including its ventral lateral, ventral anterior, and ventral posterior lateral nuclei, and the pulvinar. Discussion: Sensorimotor dysfunction in RLS seems to be reflected by decreased functional connectivity within the dopaminergic pathways. Network extension in the thalamus can be regarded as an adaptation to somatosensory dysfunction in RLS. This differential functional connectivity pattern extends prior findings on cerebral somatosensory processing in RLS and offers an explanation for the efficacy of dopaminergic treatment.
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Affiliation(s)
| | | | - Jan Kassubek
- Department of Neurology, University of Ulm, Oberer Eselsberg 45, Ulm, 89081, Germany
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Cubo E, Collazo Riobo C, Gallego-Nieto C, Elizari-Roncal M, Barroso-Pérez T, Calvo S, Echavarria A, Marras C. Survival in Restless Legs Syndrome: An 11-Year Surveillance, Community-Based Population Study. Neuroepidemiology 2020; 54:375-382. [DOI: 10.1159/000508855] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 05/20/2020] [Indexed: 11/19/2022] Open
Abstract
<b><i>Background:</i></b> A growing body of evidence relates restless legs syndrome (RLS) to an increased risk of mortality attributable to both cerebrovascular and cardiovascular events. The aim was to investigate survival in patients with RLS. <b><i>Methods:</i></b> This was an observational, retrospective longitudinal study of a cohort of patients followed up for 11 years. RLS was diagnosed by a physician using the International RLS Study Group criteria. Mortality was analyzed using age-standardized mortality ratios (SMR: observed/expected deaths) and Cox regression analysis. <b><i>Results:</i></b> Vital status was studied in a cohort of 232 patients: 181 women (78%), 96 with RLS (41.4%) with a mean age at baseline of 49.8 ± 15.0 years and a mean RLS duration of 14.1 ± 1.9 years, and 136 non-RLS (58.6%) with a mean age of 51.3 ± 14.9 years. This RLS cohort was followed up for a period of 10.4 ± 2.0 years. As of September 2019, 17 (7.3%) patients died (6 with RLS, 6.3%), and the most frequent cause was oncological (66.7%). A total of 944 person-years of observations were available for survival analysis. RLS was not associated with increased mortality in adjusted Cox regression analysis (HR = 1.12, 95% CI: 0.40–3.15), and survival was similar to that expected for the general population (SMR = 0.61, 95% CI: 0.27–1.36). <b><i>Conclusions:</i></b> RLS seems not to be associated with increased mortality compared to the general population. Still, studies with prospective data collection with large samples are needed to study the long-term mortality risk factors in RLS cohorts.
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Allen RP, Earley CJ, Jones BC, Unger EL. Iron-deficiency and dopaminergic treatment effects on RLS-Like behaviors of an animal model with the brain iron deficiency pattern of the restless legs syndrome. Sleep Med 2020; 71:141-148. [PMID: 32094092 PMCID: PMC7302997 DOI: 10.1016/j.sleep.2020.01.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 01/16/2020] [Accepted: 01/20/2020] [Indexed: 11/16/2022]
Abstract
BACKGROUND Brain iron deficiency (BID), especially for the substantia nigra (SN), without peripheral iron deficiency (ID) has been well documented as a ubiquitous finding for restless legs syndrome (RLS) patients. This close association suggests the biology of RLS BID can produce RLS symptoms. Association, however, cannot establish such a direct relationship. Instead, the BID of RLS could be experimentally produced to determine if it then produces significant RLS-like biological or behavioral features. Forward genetics approach led to identification from the BXD strains the BXD40 females (BXD40f) as a putative animal model for the RLS BID. The BXD40f on an iron-sufficient diet have a lower iron in the VMB (containing the SN) during the active but not inactive period. This was not found for the other BXD strains evaluated. The BXD40f on an ID diet uniquely have even greater reduced VMB but not peripheral iron, matching the RLS BID pathophysiology. A prior report found that the BXD40f on an iron-sufficient diet had an RLS-like behavior of increased activity occurring only in the last part of the active period that was not present in the other strains without the low VMB iron. This increased activity matches the circadian pattern of symptoms in RLS patients with increased urge or drive to move in the last part of the day. This study asks first: if you decrease the VMB iron by an iron deficient diet do the RLS-like behaviors worsen; and second will the dopaminergic treatments effective for RLS also reduce the worsened RLSlike behaviors. METHODS In sum, 13 BXD40f mice post weaning were randomly assigned for 100 days to either a iron-sufficient diet (n = 6) or an ID diet (N = 7). They were then evaluated for 24-h activity in their home cage using implanted G2 EMitter telemetry device. At 3 h before the end of the active period IP doses were given every other day of either: saline (vehicle only), 12.5 mg levodopa, 25 mg levodopa, 0.5 mg quinpirole, or 1 0.0 mg quinpirole. RESULTS The ID compared to irons-sufficient diet produced earlier onset of the RLS-like behavior matching the earlier onset of symptoms with increasing severity of RLS. The dopaminergic treatments significantly reduced the RLS-like behavior. Added analyses of the RLS-like behaviors as decreased resting times showed similar results to activity increases. CONCLUSIONS These data demonstrate both that The BXD40f provide a useful animal model of RLS and also strongly support the hypothesis that the biology of RLS BID can produce RLS symptoms.
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Affiliation(s)
- Richard P Allen
- Department of Neurology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA.
| | - Christopher J Earley
- Department of Neurology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Byron C Jones
- Department of Genetics, Genomics and Informatics, University of Tennessee, Memphis, TN, USA
| | - Erica L Unger
- Department of Biology, Lebanon Valley College, Annville, PA, USA
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de Paiva JPQ, Magalhães SC, Moura LM, Sato JR, Amaro E, Sterr A, Schlaffke L, Eckeli AL, do Prado GF, Conforto AB. Sensorimotor white matter projections and disease severity in primary Restless Legs Syndrome/Willis-Ekbom disease: a multimodal DTI analysis. Sleep Med 2020; 73:106-116. [PMID: 32805477 DOI: 10.1016/j.sleep.2020.05.040] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 05/22/2020] [Accepted: 05/26/2020] [Indexed: 01/18/2023]
Abstract
BACKGROUND Restless Legs Syndrome, a potentially disabling sleep disorder, also known as Willis-Ekbom disease (RLS/WED), may be caused by loss of inhibitory modulation of descending central motor pathways, structural changes in the somatosensory cortex, abnormal connectivity between motor and sensory areas, as well as by subtle abnormalities in white matter micro-organization. OBJECTIVE To compare diffusion-tensor imaging (DTI) metrics in areas associated with sensory or motor function, as well as sensorimotor integration, between subjects with primary mild-to-severe RLS/WED and controls. METHODS DTI metrics were assessed in 38 subjects with RLS/WED (14 mild to moderate, 24 severe to very severe) and 24 healthy age-matched controls with whole-brain Tract Based Spatial Statistics (TBSS), Region-of-interest (ROI) and probabilistic tractography based analyses. The ROIs corresponded to the corticospinal tract (CST) at the level of the cerebral peduncle; the superior, middle and inferior cerebellar peduncles. Subgroup analyses were made according to the severity of RLS/WED symptoms. The corticospinal tract was evaluated with probabilistic tractography. We also explored associations between significant findings and severity of symptoms with the Spearman's correlation coefficient. RESULTS TBSS analysis revealed decreased axial diffusivity (AD) in the left posterior thalamic radiation in RLS/WED. In subjects with severe RLS/WED, AD was reduced in the left posterior corona radiata and this reduction was negatively correlated with severity of symptoms. ROI-based analysis showed that radial diffusivity (RD) was increased in the superior cerebellar peduncles of individuals with severe RLS/WED. Tractography did not show between-group or subgroup differences. CONCLUSIONS Our results are consistent with subtle white matter changes, prominently in RLS/WED subjects with more severe symptoms, in areas related to sensory or motor function, as well as to sensorimotor integration, compared to controls. These findings support the hypothesis, raised by prior pathophysiological studies, of defective integration within these networks.
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Affiliation(s)
- Joselisa Péres Queiroz de Paiva
- Brain Institute, Hospital Israelita Albert Einstein (HIAE), São Paulo, SP, Brazil; Imaging Research Center, Hospital Israelita Albert Einstein (HIAE), São Paulo, SP, Brazil.
| | - Samir Câmara Magalhães
- Brain Institute, Hospital Israelita Albert Einstein (HIAE), São Paulo, SP, Brazil; Universidade de Fortaleza (UNIFOR), Unifor, Fortaleza, CE, Brazil
| | - Luciana Monteiro Moura
- Imaging Research Center, Hospital Israelita Albert Einstein (HIAE), São Paulo, SP, Brazil
| | - João Ricardo Sato
- Center for Mathematics, Computing and Cognition, Universidade Federal do ABC (UFABC), São Bernardo do Campo, SP, Brazil
| | - Edson Amaro
- Brain Institute, Hospital Israelita Albert Einstein (HIAE), São Paulo, SP, Brazil; Imaging Research Center, Hospital Israelita Albert Einstein (HIAE), São Paulo, SP, Brazil; Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP, Brazil
| | - Annette Sterr
- School of Psychology, University of Surrey, Guildford, UK
| | - Lara Schlaffke
- Department of Neurology, BG University Clinic Bergmannsheil, Ruhr-University Bochum, Bochum, Germany
| | - Alan Luiz Eckeli
- Department of Neurosciences and Behavioral Sciences, Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | | | - Adriana Bastos Conforto
- Brain Institute, Hospital Israelita Albert Einstein (HIAE), São Paulo, SP, Brazil; Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP, Brazil
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30
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Acute post-stroke restless legs syndrome: the body of caudate nucleus considerations. Sleep Med 2020; 70:66-70. [DOI: 10.1016/j.sleep.2019.11.1253] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 10/25/2019] [Accepted: 11/19/2019] [Indexed: 11/22/2022]
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Ahmed N, Kandil M, Elfil M, Jamal A, Koo BB. Hypothyroidism in restless legs syndrome. J Sleep Res 2020; 30:e13091. [PMID: 32483857 DOI: 10.1111/jsr.13091] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 04/14/2020] [Accepted: 05/04/2020] [Indexed: 01/17/2023]
Abstract
The diurnal nature of restless legs syndrome (RLS) and its response to dopamine hint that hormones are central in RLS pathophysiology. Hypothyroidism has been linked to RLS, but studies are limited. This study's objective is to determine whether RLS is more prevalent in persons with hypothyroidism and whether hypothyroidism is more prevalent in RLS sufferers. Persons with hypothyroidism and controls were recruited through an on-line registry of potential research participants. RLS was assessed using the Cambridge-Hopkins questionnaire. RLS persons and controls were recruited through RLS Foundation and on-line registry advertisements and assessed for hypothyroidism by self-report. The International RLS Study Group Severity Scale assessed RLS severity; 266 hypothyroid subjects and 321 controls were comparable in age (52.3 ± 13.4 versus 53.9 ± 11.7 years; p = .14) and gender (91.7% versus 91.3% women; p = .85), as were 354 RLS and 313 controls (59.1 ± 13.2 versus 58.2 ± 13.6 years; p = .41; 80.8% versus 78.3% women; p = .42). Hypothyroid participants versus controls had a significantly higher prevalence of RLS (14.3% versus 8.1%; p = .02). RLS participants versus controls had a significantly higher prevalence of hypothyroidism (22.3% versus. 13.8%; p = .005). RLS severity was similar in persons with and without hypothyroidism. Among 73 persons with RLS and hypothyroidism, 14 previously were hyperthyroid versus 0 of 37 persons with hypothyroidism alone (p = .004). RLS prevalence is increased in individuals with hypothyroidism; hypothyroidism prevalence is increased in individuals with RLS. Persons with hypothyroidism and RLS are significantly more likely than those with hypothyroidism alone to have had hyperthyroidism prior to hypothyroidism. Associations between RLS and thyroid disease may shed light on complex biological mechanisms underlying RLS.
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Affiliation(s)
- Nada Ahmed
- Department of Neurology, Yale University, New Haven, Connecticut, USA
| | - Mohamed Kandil
- Department of Neurology, Yale University, New Haven, Connecticut, USA
| | - Mohamed Elfil
- Department of Neurology, Yale University, New Haven, Connecticut, USA
| | - Abdalla Jamal
- Department of Neurology, Yale University, New Haven, Connecticut, USA
| | - Brian B Koo
- Department of Neurology, Yale University, New Haven, Connecticut, USA.,Center for Neuroepidemiology and Clinical Neurologic Research, New Haven, Connecticut, USA
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Lyu S, Doroodchi A, Xing H, Sheng Y, DeAndrade MP, Yang Y, Johnson TL, Clemens S, Yokoi F, Miller MA, Xiao R, Li Y. BTBD9 and dopaminergic dysfunction in the pathogenesis of restless legs syndrome. Brain Struct Funct 2020; 225:1743-1760. [PMID: 32468214 DOI: 10.1007/s00429-020-02090-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Accepted: 05/13/2020] [Indexed: 01/17/2023]
Abstract
Restless legs syndrome (RLS) is characterized by an urge to move legs, usually accompanied by uncomfortable sensations. RLS symptoms generally happen at night and can be relieved by movements. Genetic studies have linked polymorphisms in BTBD9 to a higher risk of RLS. Knockout of BTBD9 homolog in mice (Btbd9) and fly results in RLS-like phenotypes. A dysfunctional dopaminergic system is associated with RLS. However, the function of BTBD9 in the dopaminergic system and RLS is not clear. Here, we made use of the simple Caenorhabditis elegans nervous system. Loss of hpo-9, the worm homolog of BTBD9, resulted in hyperactive egg-laying behavior. Analysis of genetic interactions between hpo-9 and genes for dopamine receptors (dop-1, dop-3) indicated that hpo-9 and dop-1 worked similarly. Reporter assays of dop-1 and dop-3 revealed that hpo-9 knockout led to a significant increase of DOP-3 expression. This appears to be evolutionarily conserved in mice with an increased D2 receptor (D2R) mRNA in the striatum of the Btbd9 knockout mice. Furthermore, the striatal D2R protein was significantly decreased and Dynamin I was increased. Overall, activities of DA neurons in the substantia nigra were not altered, but the peripheral D1R pathway was potentiated in the Btbd9 knockout mice. Finally, we generated and characterized the dopamine neuron-specific Btbd9 knockout mice and detected an active-phase sleepiness, suggesting that dopamine neuron-specific loss of Btbd9 is sufficient to disturb the sleep. Our results suggest that increased activities in the D1R pathway, decreased activities in the D2R pathway, or both may contribute to RLS.
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Affiliation(s)
- Shangru Lyu
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, College of Medicine, University of Florida, PO Box 100236, Gainesville, FL, 32610-0236, USA
| | - Atbin Doroodchi
- Department of Cell, Developmental and Integrative Biology, The University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Hong Xing
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, College of Medicine, University of Florida, PO Box 100236, Gainesville, FL, 32610-0236, USA
| | - Yi Sheng
- Department of Aging and Geriatric Research, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Mark P DeAndrade
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, College of Medicine, University of Florida, PO Box 100236, Gainesville, FL, 32610-0236, USA
| | - Youfeng Yang
- Department of Cell, Developmental and Integrative Biology, The University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Tracy L Johnson
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - Stefan Clemens
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - Fumiaki Yokoi
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, College of Medicine, University of Florida, PO Box 100236, Gainesville, FL, 32610-0236, USA
| | - Michael A Miller
- Department of Cell, Developmental and Integrative Biology, The University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Rui Xiao
- Department of Aging and Geriatric Research, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Yuqing Li
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, College of Medicine, University of Florida, PO Box 100236, Gainesville, FL, 32610-0236, USA.
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Lyu S, Xing H, DeAndrade MP, Perez PD, Yokoi F, Febo M, Walters AS, Li Y. The Role of BTBD9 in the Cerebellum, Sleep-like Behaviors and the Restless Legs Syndrome. Neuroscience 2020; 440:85-96. [PMID: 32446853 DOI: 10.1016/j.neuroscience.2020.05.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 04/27/2020] [Accepted: 05/14/2020] [Indexed: 12/28/2022]
Abstract
Recent genome-wide association studies (GWAS) have found cerebellum as a top hit for sleep regulation. Restless legs syndrome (RLS) is a sleep-related sensorimotor disorder characterized by uncomfortable sensations in the extremities, generally at night, which are often relieved by movements. Clinical studies have found that RLS patients have structural and functional abnormalities in the cerebellum. However, whether and how cerebellar pathology contributes to sleep regulation and RLS is not known. GWAS identified polymorphisms in BTBD9 conferring a higher risk of sleep disruption and RLS. Knockout of the BTBD9 homolog in mice (Btbd9) and fly results in motor restlessness and sleep disruption. We performed manganese-enhanced magnetic resonance imaging on the Btbd9 knockout mice and found decreased neural activities in the cerebellum, especially in lobules VIII, X, and the deep cerebellar nuclei. Electrophysiological recording of Purkinje cells (PCs) from Btbd9 knockout mice revealed an increased number of non-tonic PCs. Tonic PCs showed increased spontaneous activity and intrinsic excitability. To further investigate the cerebellar contribution to RLS and sleep-like behaviors, we generated PC-specific Btbd9 knockout mice (Btbd9 pKO) and performed behavioral studies. Btbd9 pKO mice showed significant motor restlessness during the rest phase but not in the active phase. Btbd9 pKO mice also had an increased probability of waking at rest. Unlike the Btbd9 knockout mice, there was no increased thermal sensation in the Btbd9 pKO. Our results indicate that the Btbd9 knockout influences the PC activity; dysfunction in the cerebellum may contribute to the motor restlessness found in the Btbd9 knockout mice.
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Affiliation(s)
- Shangru Lyu
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Hong Xing
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Mark P DeAndrade
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Pablo D Perez
- Department of Psychiatry, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Fumiaki Yokoi
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Marcelo Febo
- Department of Psychiatry, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Arthur S Walters
- Division of Sleep Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Yuqing Li
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA.
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Didato G, Di Giacomo R, Rosa GJ, Dominese A, de Curtis M, Lanteri P. Restless Legs Syndrome across the Lifespan: Symptoms, Pathophysiology, Management and Daily Life Impact of the Different Patterns of Disease Presentation. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:E3658. [PMID: 32456058 PMCID: PMC7277795 DOI: 10.3390/ijerph17103658] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 05/17/2020] [Accepted: 05/18/2020] [Indexed: 12/14/2022]
Abstract
Restless legs syndrome is a common but still underdiagnosed neurologic disorder, characterized by peculiar symptoms typically occurring in the evening and at night, and resulting in sleep disruption and daily functioning impairment. This disease can affect subjects of all age ranges and of both sexes, manifesting itself with a broad spectrum of severity and deserving special attention in certain patient categories, in order to achieve a correct diagnosis and an effective treatment. The diagnosis of restless legs syndrome can be challenging in some patients, especially children and elderly people, and an effective treatment might be far from being easy to achieve after some years of drug therapy, notably when dopaminergic agents are used. Moreover, the pathophysiology of this disorder offers an interesting example of interaction between genetics and the environment, considering strong iron metabolism involvement and its interaction with recognized individual genetic factors. Therefore, this syndrome allows clinicians to verify how lifespan and time can modify diagnosis and treatment of a neurological disorder.
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Affiliation(s)
- Giuseppe Didato
- Clinical and Experimental Epileptology and Sleep Disorders Unit, Foundation IRCCS Carlo Besta Neurological Institute, Via Celoria 11, 20133 Milan, Italy; (R.D.G.); (G.J.R.); (A.D.); (M.d.C.)
| | - Roberta Di Giacomo
- Clinical and Experimental Epileptology and Sleep Disorders Unit, Foundation IRCCS Carlo Besta Neurological Institute, Via Celoria 11, 20133 Milan, Italy; (R.D.G.); (G.J.R.); (A.D.); (M.d.C.)
| | - Giuseppa Jolanda Rosa
- Clinical and Experimental Epileptology and Sleep Disorders Unit, Foundation IRCCS Carlo Besta Neurological Institute, Via Celoria 11, 20133 Milan, Italy; (R.D.G.); (G.J.R.); (A.D.); (M.d.C.)
- Neurology Unit, University Hospital of Ferrara, 44100 Ferrara, Italy
| | - Ambra Dominese
- Clinical and Experimental Epileptology and Sleep Disorders Unit, Foundation IRCCS Carlo Besta Neurological Institute, Via Celoria 11, 20133 Milan, Italy; (R.D.G.); (G.J.R.); (A.D.); (M.d.C.)
| | - Marco de Curtis
- Clinical and Experimental Epileptology and Sleep Disorders Unit, Foundation IRCCS Carlo Besta Neurological Institute, Via Celoria 11, 20133 Milan, Italy; (R.D.G.); (G.J.R.); (A.D.); (M.d.C.)
| | - Paola Lanteri
- Neurophysiopathology Unit, Foundation IRCCS Carlo Besta Neurological Institute, 20133 Milan, Italy;
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35
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Lyu S, DeAndrade MP, Unger EL, Mueller S, Oksche A, Walters AS, Li Y. Mu opioid receptor knockout mouse: Phenotypes with implications on restless legs syndrome. J Neurosci Res 2020; 98:1532-1548. [PMID: 32424971 DOI: 10.1002/jnr.24637] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 04/12/2020] [Accepted: 04/17/2020] [Indexed: 12/19/2022]
Abstract
Restless legs syndrome (RLS) is characterized by an irresistible need to move the legs while sitting or lying at night with insomnia as a frequent consequence. Human RLS has been associated with abnormalities in the endogenous opioid system, the dopaminergic system, the iron regulatory system, anemia, and inflammatory and auto-immune disorders. Our previous work indicates that mice lacking all three subtypes of opioid receptors have a phenotype similar to that of human RLS. To study the roles of each opioid receptor subtype in RLS, we first used mu opioid receptor knockout (MOR KO) mice based on our earlier studies using postmortem brain and cell culture. The KO mice showed decreased hemoglobin, hematocrit, and red blood cells (RBCs), with an appearance of microcytic RBCs indicating anemia. Together with decreased serum iron and transferrin, but increased ferritin levels, the anemia is similar to that seen with chronic inflammation in humans. A decreased serum iron level was also observed in the wildtype mice treated with an MOR antagonist. Iron was increased in the liver and spleen of the KO mice. Normal circadian variations in the dopaminergic and serotoninergic systems were absent in the KO mice. The KO mice showed hyperactivity and increased thermal sensitivity in wakefulness primarily during what would normally be the sleep phase similar to that seen in human RLS. Deficits in endogenous opioid system transmission could predispose to anemia of inflammation and loss of circadian variations in dopaminergic or serotonergic systems, thereby contributing to an RLS-like phenotype.
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Affiliation(s)
- Shangru Lyu
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Mark P DeAndrade
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Erica L Unger
- Department of Biology, Lebanon Valley College, Annville, PA, USA
| | | | - Alexander Oksche
- Mundipharma Research Limited, Cambridge, UK.,Rudolf-Buchheim-Institut für Pharmakologie, University of Giessen, Giessen, Germany
| | - Arthur S Walters
- Division of Sleep Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Yuqing Li
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
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The Role of BTBD9 in Striatum and Restless Legs Syndrome. eNeuro 2019; 6:ENEURO.0277-19.2019. [PMID: 31444227 PMCID: PMC6787346 DOI: 10.1523/eneuro.0277-19.2019] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 07/22/2019] [Accepted: 08/02/2019] [Indexed: 12/23/2022] Open
Abstract
Restless legs syndrome (RLS) is a sensory-motor neurological disorder characterized by uncomfortable sensations in the extremities, generally at night, which is often relieved by movements. Genome-wide association studies (GWAS) have identified mutations in BTBD9 conferring a higher risk of RLS. Knockout of the BTBD9 homolog in mice (Btbd9) and fly results in motor restlessness and sleep disruption. Clinical studies have found RLS patients have structural and functional abnormalities in the striatum; however, whether and how striatal pathology contributes to the pathogenesis of RLS is not known. Here, we used fMRI to map regions of altered synaptic activity in basal ganglia of systematic Btbd9 knock-out (KO) mice. We further dissected striatal circuits using patch-clamp electrophysiological recordings in brain slices. Two different mouse models were generated to test the effect of specific knockout of Btbd9 in either striatal medium spiny neurons (MSNs) or cholinergic interneurons (ChIs) using the electrophysiological recording, motor and sensory behavioral tests. We found that Btbd9 KO mice showed enhanced neural activity in the striatum, increased postsynaptic currents in the MSNs, and decreased excitability of the striatal ChIs. Knocking out Btbd9 specifically in the striatal MSNs, but not the ChIs, led to rest-phase specific motor restlessness, sleep disturbance, and increased thermal sensation in mice, which are consistent with results obtained from the Btbd9 KO mice. Our data establish the role of Btbd9 in regulating the activity of striatal neurons. Increased activity of the striatal MSNs, possibly through modulation by the striatal ChIs, contributes to the pathogenesis of RLS.
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Hopfner F, Hobert MA, Maetzler C, Hansen C, Pham MH, Moreau C, Berg D, Devos D, Maetzler W. Mobility Deficits Assessed With Mobile Technology: What Can We Learn From Brain Iron-Altered Animal Models? Front Neurol 2019; 10:833. [PMID: 31440200 PMCID: PMC6694697 DOI: 10.3389/fneur.2019.00833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 07/18/2019] [Indexed: 12/02/2022] Open
Abstract
Background: Recent developments in mobile technology have enabled the investigation of human movements and mobility under natural conditions, i.e., in the home environment. Iron accumulation in the basal ganglia is deleterious in Parkinson's disease (i.e., iron accumulation with lower striatal level of dopamine). The effect of iron chelation (i.e., re-deployment of iron) in Parkinson's disease patients is currently tested in a large investigator-initiated multicenter study. Conversely, restless legs syndrome (RLS) is associated with iron depletion and higher striatal level of dopamine. To determine from animal models which movement and mobility parameters might be associated with iron content modulation and the potential effect of therapeutic chelation inhuman. Methods: We recapitulated pathophysiological aspects of the association between iron, dopamine, and neuronal dysfunction and deterioration in the basal ganglia, and systematically searched PubMed to identify original articles reporting about quantitatively assessed mobility deficits in animal models of brain iron dyshomeostasis. Results: We found six original studies using murine and fly models fulfilling the inclusion criteria. Especially postural and trunk stability were altered in animal models with iron overload. Animal models with lowered basal ganglia iron suffered from alterations in physical activity, mobility, and sleep fragmentation. Conclusion: From preclinical investigations in the animal model, we can deduce that possibly also in humans with iron accumulation in the basal ganglia undergoing therapeutic chelation may primarily show changes in physical activity (such as daily “motor activity”), postural and trunk stability and sleep fragmentation. These changes can readily be monitored with currently available mobile technology.
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Affiliation(s)
- Franziska Hopfner
- Department of Neurology, University Hospital Schleswig-Holstein, Christian-Albrechts-Universität zu Kiel, Kiel, Germany.,Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Markus A Hobert
- Department of Neurology, University Hospital Schleswig-Holstein, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Corina Maetzler
- Department of Neurology, University Hospital Schleswig-Holstein, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Clint Hansen
- Department of Neurology, University Hospital Schleswig-Holstein, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Minh Hoang Pham
- Department of Neurology, University Hospital Schleswig-Holstein, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Caroline Moreau
- Department of Movement Disorders and Neurology, Faculty of Medicine, Lille University Hospital, Lille University, INSERM U1171, Lille, France
| | - Daniela Berg
- Department of Neurology, University Hospital Schleswig-Holstein, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - David Devos
- Departments of Medical Pharmacology and Movement Disorders, Lille University Hospital, Lille University, INSERM U1171, Lille, France
| | - Walter Maetzler
- Department of Neurology, University Hospital Schleswig-Holstein, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
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Lyu S, DeAndrade MP, Mueller S, Oksche A, Walters AS, Li Y. Hyperactivity, dopaminergic abnormalities, iron deficiency and anemia in an in vivo opioid receptors knockout mouse: Implications for the restless legs syndrome. Behav Brain Res 2019; 374:112123. [PMID: 31376441 DOI: 10.1016/j.bbr.2019.112123] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 07/24/2019] [Accepted: 07/30/2019] [Indexed: 12/13/2022]
Abstract
Previous studies have uncovered a potential role of the opioid system in iron hemostasis and dopamine metabolism. Abnormalities in both of these systems have been noted in human RLS. Autopsy studies of human RLS have shown an endogenous opioid deficiency in the thalamus. Opioids, particularly prolonged-release oxycodone/naloxone, have been approved in Europe to be a second-line therapy for severe restless legs syndrome (RLS). To study the role of opioid receptors in the pathogenesis of RLS, we used a triple knockout (KO) mouse strain that lack mu, delta, and kappa opioid receptors and explored the behavioral and biochemical parameters relevant to RLS. The triple KO mice showed hyperactivity and a trend of increased probability of waking during the rest period (day) akin to that in human RLS (night). Surprisingly, triple KO mice also exhibit decreased serum iron concentration, evidence of anemia, a significant dysfunction in dopamine metabolism akin to that noted in human RLS, as well as an increased latency in response to thermal stimuli. To our knowledge, this is the first study to demonstrate that the endogenous opioid system may play a role in iron metabolism and subsequently in the pathogenesis of anemia. It is also the first study showing that opioid receptors are involved in the production of motor restlessness with a circadian predominance. Our findings support the role of endogenous opioids in the pathogenesis of RLS, and the triple KO mice can be used to understand the relationship between iron deficiency, anemia, dopaminergic dysfunction, and RLS.
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Affiliation(s)
- Shangru Lyu
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Mark P DeAndrade
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Stefan Mueller
- Mundipharma Research GmbH & Co. KG, Höhenstraße 10, Limburg, Germany
| | - Alexander Oksche
- Mundipharma Research Limited, Cambridge, UK; Rudolf-Buchheim-Institut für Pharmakologie, University of Giessen, Giessen, Germany
| | - Arthur S Walters
- Division of Sleep Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Yuqing Li
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA.
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Cubo E, Gallego-Nieto C, Elizari-Roncal M, Barroso-Pérez T, Collazo C, Calvo S, Delgado-López PD. Is Restless Legs Syndrome Associated with an Increased Risk of Mortality? A Meta-Analysis of Cohort Studies. TREMOR AND OTHER HYPERKINETIC MOVEMENTS (NEW YORK, N.Y.) 2019; 9:650. [PMID: 31413895 PMCID: PMC6691746 DOI: 10.7916/tohm.v0.650] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 04/06/2019] [Indexed: 12/01/2022]
Abstract
Background Restless legs syndrome (RLS) is a common sleep disorder,. although controversial, growing evidence relates the presence of RLS to an increased risk of mortality, mainly due to cardiovascular events. The aim of this article was to review the role of RLS as a risk factor of mortality according to independent cohort studies. Methods We performed a literature review via PubMed database for articles relating RLS and mortality. We used the random-effects model to calculate the pooled effect estimates on mortality. Heterogeneity between studies was assessed using quantitative and qualitative analysis. Results Out of 100 articles identified, 13 were finally included. Although studies were heterogeneous (p = 0.001), no significant publication bias was found. When all cohort studies were considered, the random-effects model yielded a significantly increased risk of mortality in RLS versus non-RLS patients (13 studies, hazard ratio [HR] = 1.52, 95% confidence interval [CI] 1.28-1.80). However, this association was not statistically significant when only cohort studies using the international RLS diagnostic criteria were considered (5 studies, HR = 1.63, 95% CI 0.94-2.81). Discussion The results of this meta-analysis suggest that RLS seems to be a risk factor of mortality, although this association is conditioned by the diagnostic criteria used in the studies. Future long-term follow-up standardized mortality studies are needed to address this important question that carries potential impact on population global health.
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Affiliation(s)
- Esther Cubo
- Neurology Department, Hospital Universitario Burgos, ES.,Health Science Department, University of Burgos, ES
| | | | | | | | | | - Sara Calvo
- Research Unit, Hospital Universitario Burgos, ES
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D3 and D1 receptors: The Yin and Yang in the treatment of restless legs syndrome with dopaminergics. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2019; 84:79-100. [PMID: 31229178 DOI: 10.1016/bs.apha.2019.01.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Dopaminergic treatments targeting the D3 receptor subtype to reduce the symptoms of RLS show substantial initial clinical benefits but fail to maintain their efficacy over time. Sensorimotor circuits in the spinal cord are the gateway for the sensory processing of the symptoms and critical for the associated leg movements that relieve the symptoms and the periodic limb movements that often develop during sleep. There is a high preponderance of the inhibitory D3 receptor in the sensory-processing areas of the spinal cord (dorsal horn), whereas the motor areas in the ventral horn more strongly express the excitatory D1 receptor subtype. D3 and D1 receptors can form functional heteromeric ensembles that influence each other. In the spinal cord, long-term treatment with D3 receptor agonists is associated with the upregulation of the D1 receptor subtype and block of D1 receptor function at this stage can restore the D3 receptor effect. Alternate scenarios for a role of dopamine involve a role for the D5 receptor in regulating motor excitability and for the D4 receptor subtype in controlling D3-like effects. A model emerges that proposes that the behavioral changes in RLS, while responsive to D3 receptor agonists, may be ultimately be the result of unmasked increased D1-like receptor activities.
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ZHANG L, SUN Y, WANG T, PAN Y, YAO Y, PAN L, XU Q, ZHANG W, XU J, HU X. [Restless legs syndrome in ischemic stroke patients: clinical features and significance]. Zhejiang Da Xue Xue Bao Yi Xue Ban 2019; 48:275-281. [PMID: 31496159 PMCID: PMC8800815 DOI: 10.3785/j.issn.1008-9292.2019.06.07] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 04/21/2019] [Indexed: 06/10/2023]
Abstract
OBJECTIVE To investigate the clinical features and implication of restless legs syndrome (RLS) in ischemic stroke patients. METHODS A total of 199 ischemic stroke patients were enrolled and assessed by polysomnography (PSG). RLS was identified according to criteria of International Restless Legs Syndrome Study Group. Epworth Sleepiness Scale (ESS), Mini-mental State Examination (MMSE) and Patient Health Questionnaire (PHQ-9) were used to evaluate the sleep quality, cognitive function and post-stroke depression, respectively. The National Institute of Health Stroke Scale (NIHSS) was used to evaluate the neurological function 3 months after stroke onset. Gender-and age-matched non-ischemic stroke patients with RLS (primary PLS) were selected as controls. RESULTS Twenty-two cases of RLS were identified among 199 ischemic stroke patients (11.1%). Generalized linear model and logistic regression showed that low serum ferritin level (β=-133.3 mg/L, 95%CI:-200.4--0.1, P<0.01), subcortical infarction (OR=4.05, 95%CI:1.15-14.18, P<0.05) and female (OR=2.54, 95%CI:1.04-6.23, P<0.05) were identified as the risk factors of RLS in ischemic stroke patients. Compared with ischemic stroke patients without RLS, ESS increased by 4.37 (95%CI:2.33-6.41, P<0.01), PHQ-9 increased by 2.17 (95%CI:0.39--3.94, P<0.05), and reduced NIHSS from the baseline deceased by 0.97 (95%CI:-1.79--0.15, P<0.05) in ischemic stroke patients with RLS. In addition, the incidence of moderate-severe depression increased (OR=4.27, 95%CI:1.40-13.10, P<0.05) in ischemic stroke patients with RLS. The index of periodic leg movements of sleep (PLMS) with arousal in ischemic stroke patients with RLS was significantly higher than that in patients with primary RLS (β=12.85, 95%CI:2.04-23.67, P<0.05). CONCLUSIONS RLS is common in ischemic stroke patients and has adverse influences on patients.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Xingyue HU
- 胡兴越(1962-), 男, 博士, 主任医师, 博士生导师, 主要从事神经内科疾病研究; E-mail:
,
https://orcid.org/0000-0003-3458-2590
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Ghorayeb I. Idiopathic restless legs syndrome treatment: Progress and pitfalls? PHARMACOLOGY OF RESTLESS LEGS SYNDROME (RLS) 2019; 84:207-235. [DOI: 10.1016/bs.apha.2019.01.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Ferré S, García-Borreguero D, Allen RP, Earley CJ. New Insights into the Neurobiology of Restless Legs Syndrome. Neuroscientist 2018; 25:113-125. [PMID: 30047288 DOI: 10.1177/1073858418791763] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Restless legs syndrome (RLS) is a common sensorimotor disorder, whose basic components include a sensory experience, akathisia, and a sleep-related motor sign, periodic leg movements during sleep (PLMS), both associated with an enhancement of the individual's arousal state. The present review attempts to integrate the major clinical and experimental neurobiological findings into a heuristic pathogenetic model. The model also integrates the recent findings on RLS genetics indicating that RLS has aspects of a genetically moderated neurodevelopmental disorder involving mainly the cortico-striatal-thalamic-cortical circuits. Brain iron deficiency (BID) remains the key initial pathobiological factor and relates to alterations of iron acquisition by the brain, also moderated by genetic factors. Experimental evidence indicates that BID leads to a hyperdopaminergic and hyperglutamatergic states that determine the dysfunction of cortico-striatal-thalamic-cortical circuits in genetically vulnerable individuals. However, the enhanced arousal mechanisms critical to RLS are better explained by functional changes of the ascending arousal systems. Recent experimental and clinical studies suggest that a BID-induced hypoadenosinergic state provides the link for a putative unified pathophysiological mechanism for sensorimotor signs of RLS and the enhanced arousal state.
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Affiliation(s)
- Sergi Ferré
- 1 National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
| | | | - Richard P Allen
- 3 Department of Neurology, Johns Hopkins University, Baltimore, MD, USA
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Ferini-Strambi L, Carli G, Casoni F, Galbiati A. Restless Legs Syndrome and Parkinson Disease: A Causal Relationship Between the Two Disorders? Front Neurol 2018; 9:551. [PMID: 30087647 PMCID: PMC6066514 DOI: 10.3389/fneur.2018.00551] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 06/19/2018] [Indexed: 11/13/2022] Open
Abstract
Restless Legs Syndrome/Willis-Ekbom Disease (RLS/WED) is a common sleep related movement disorder that can be idiopathic or occurs in comorbidity with other medical conditions such as polyneuropathy, iron deficiency anemia, multiple sclerosis, hypertension and cardiovascular diseases. In recent years, a growing body of literature investigated the association between RLS/WED and Parkinson's Disease (PD). Several questions regarding the comorbidity between these two disorders are still unanswered. If the insurgence of RLS/WED may precede the onset of PD, or if RLS/WED could represent a secondary condition of PD and if impaired dopaminergic pathway may represent a bridge between these two conditions are still debatable issues. In this review, we critically discuss the relationship between RLS/WED and PD by reviewing cross sectional and longitudinal studies, as well as the role of dopamine in these disorders. A twofold interpretation have to be taken into account: dopaminergic therapy may have a crucial role in the development of RLS/WED in PD patients or RLS/WED can be conceived as an early manifestation of PD rather than a risk factor. Several studies showed a high prevalence of RLS/WED in PD patients and several findings related to dopaminergic and iron alterations in both disorders, however up to now it is difficult to find a point of agreement between studies. A greater number of systematic and strongly controlled longitudinal studies as well as basic pathophysiological investigations particularly in RLS/WED are needed to clarify this complex relationship.
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Affiliation(s)
- Luigi Ferini-Strambi
- Department of Clinical Neurosciences, IRCCS San Raffaele Scientific Institute, Neurology - Sleep Disorders Center, Milan, Italy.,Università Vita-Salute San Raffaele, Milan, Italy
| | - Giulia Carli
- Department of Clinical Neurosciences, IRCCS San Raffaele Scientific Institute, Neurology - Sleep Disorders Center, Milan, Italy
| | - Francesca Casoni
- Department of Clinical Neurosciences, IRCCS San Raffaele Scientific Institute, Neurology - Sleep Disorders Center, Milan, Italy
| | - Andrea Galbiati
- Department of Clinical Neurosciences, IRCCS San Raffaele Scientific Institute, Neurology - Sleep Disorders Center, Milan, Italy.,Università Vita-Salute San Raffaele, Milan, Italy
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Mitchell UH, Obray JD, Hunsaker E, Garcia BT, Clarke TJ, Hope S, Steffensen SC. Peripheral Dopamine in Restless Legs Syndrome. Front Neurol 2018; 9:155. [PMID: 29599746 PMCID: PMC5862810 DOI: 10.3389/fneur.2018.00155] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 03/02/2018] [Indexed: 01/24/2023] Open
Abstract
Objective/Background Restless Legs Syndrome (RLS) is a dopamine-dependent disorder characterized by a strong urge to move. The objective of this study was to evalulate blood levels of dopamine and other catecholamines and blood D2-subtype dopamine receptors (D2Rs) in RLS. Patients/Methods Dopamine levels in blood samples from age-matched unmedicated RLS subjects, medicated RLS subjects and Controls were evaluated with high performance liquid chromatography and dopamine D2R white blood cell (WBC) expression levels were determined with fluorescence-activated cell sorting and immunocytochemistry. Results Blood plasma dopamine levels, but not norepinepherine or epinephrine levels, were significantly increased in medicated RLS subjects vs unmedicated RLS subjects and Controls. The percentage of lymphocytes and monocytes expressing D2Rs differed between Control, RLS medicated and RLS unmedicated subjects. Total D2R expression in lymphocytes, but not monocytes, differed between Control, RLS medicated and RLS unmedicated subjects. D2Rs in lymphocytes, but not monocytes, were sensitive to dopamine in Controls only. Conclusion Downregulation of WBCs D2Rs occurs in RLS. This downregulation is not reversed by medication, although commonly used RLS medications increase plasma dopamine levels. The insensitivity of monocytes to dopamine levels, but their downregulation in RLS, may reflect their utility as a biomarker for RLS and perhaps brain dopamine homeostasis.
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Affiliation(s)
- Ulrike H Mitchell
- Department of Exercise Sciences, Brigham Young University, Provo, UT, United States
| | - J Daniel Obray
- Department of Psychology, Brigham Young University, Provo, UT, United States
| | - Erik Hunsaker
- Department of Exercise Sciences, Brigham Young University, Provo, UT, United States
| | - Brandon T Garcia
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, United States
| | - Travis J Clarke
- Department of Psychology, Brigham Young University, Provo, UT, United States
| | - Sandra Hope
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, United States
| | - Scott C Steffensen
- Department of Psychology, Brigham Young University, Provo, UT, United States
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Rizzo G, Plazzi G. Neuroimaging Applications in Restless Legs Syndrome. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2018; 143:31-64. [DOI: 10.1016/bs.irn.2018.09.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Zhuo Y, Wu Y, Xu Y, Lu L, Li T, Wang X, Li K. Combined resting state functional magnetic resonance imaging and diffusion tensor imaging study in patients with idiopathic restless legs syndrome. Sleep Med 2017; 38:96-103. [DOI: 10.1016/j.sleep.2017.06.033] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 06/23/2017] [Accepted: 06/27/2017] [Indexed: 11/16/2022]
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Zhang R, Brandt MD, Schrempf W, Beste C, Stock AK. Neurophysiological mechanisms of circadian cognitive control in RLS patients - an EEG source localization study. NEUROIMAGE-CLINICAL 2017; 15:644-652. [PMID: 28664035 PMCID: PMC5480014 DOI: 10.1016/j.nicl.2017.06.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 05/09/2017] [Accepted: 06/10/2017] [Indexed: 01/18/2023]
Abstract
The circadian variation of sensory and motor symptoms with increasing severity in the evening and at night is a key diagnostic feature/symptom of the restless legs syndrome (RLS). Even though many neurological diseases have shown a strong nexus between motor and cognitive symptoms, it has remained unclear whether cognitive performance of RLS patients declines in the evening and which neurophysiological mechanisms are affected by the circadian variation. In the current study, we examined daytime effects (morning vs. evening) on cognitive performance in RLS patients (n = 33) compared to healthy controls (n = 29) by analyzing flanker interference effects in combination with EEG and source localization techniques. RLS patients showed larger flanker interference effects in the evening than in the morning (p = .023), while healthy controls did not display a comparable circadian variation. In line with this, the neurophysiological data showed smaller N1 amplitudes in RLS patients compared to controls in the interfering task condition in the evening (p = .042), but not in the morning. The results demonstrate diurnal cognitive changes in RLS patients with intensified impairments in the evening. It seems that not all dopamine-regulated cognitive processes are altered in RLS and thus show daytime-dependent impairments. Instead, the daytime-related cognitive impairment emerges from attentional selection processes within the extra-striate visual cortex, but not from later cognitive processes such as conflict monitoring and response selection. RLS patients have larger flanker interference effect in the evening. RLS patients have enhanced impairment of attentional selection in the evening. Nocturnal attentional impairment relies on the extra-striate visual cortex. Conflict monitoring and response selection are not affected by RLS.
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Affiliation(s)
- Rui Zhang
- Cognitive Neurophysiology, Department of Child and Adolescent Psychiatry, Faculty of Medicine of the TU Dresden, Schubertstr. 42, 01307 Dresden, Germany.
| | - Moritz D Brandt
- Department of Neurology, Carl Gustav Carus University Hospital Dresden, Fetscherstraße 74, 01307 Dresden, Germany; German Center for Neurodegenerative Diseases (DZNE) Dresden, 01307 Dresden, Germany
| | - Wiebke Schrempf
- Department of Neurology, Carl Gustav Carus University Hospital Dresden, Fetscherstraße 74, 01307 Dresden, Germany
| | - Christian Beste
- Cognitive Neurophysiology, Department of Child and Adolescent Psychiatry, Faculty of Medicine of the TU Dresden, Schubertstr. 42, 01307 Dresden, Germany; Experimental Neurobiology, National Institute of Mental Health, Topolová 748, 250 67 Klecany, Czech Republic
| | - Ann-Kathrin Stock
- Cognitive Neurophysiology, Department of Child and Adolescent Psychiatry, Faculty of Medicine of the TU Dresden, Schubertstr. 42, 01307 Dresden, Germany
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Carlos K, Prado GF, Teixeira CDM, Conti C, de Oliveira MM, Prado LBF, Carvalho LBC. Benzodiazepines for restless legs syndrome. Cochrane Database Syst Rev 2017; 3:CD006939. [PMID: 28319266 PMCID: PMC6464545 DOI: 10.1002/14651858.cd006939.pub2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
BACKGROUND Restless legs syndrome (RLS) is a common disease affecting about 5% to 15% of the population. Symptoms of RLS can be severe in a minority of and can have a major impact on sleep, mostly sleep initiation, and quality of life. Benzodiazepines are drugs that can induce and maintain sleep and, hence, intuitively are thought to be beneficial to people with RLS. Altough benzodiazepines, particularly clonazepam, are used to treat RLS symptoms, a systematic review done by the American Academy of Sleep Medicine stated that benzodiazepines should not be used as a first-line treatment, although could be used as a coadjuvant therapy. OBJECTIVES To evaluate the efficacy and safety of benzodiazepine compared to placebo or other treatment for idiopathic RLS, including unconfounded trials comparing benzodiazepines versus open control. SEARCH METHODS In March 2016 we searched CENTRAL, MEDLINE, Embase and LILACS We checked the references of each study and contacted study authors to identify any additional studies. We considered studies published in any language. SELECTION CRITERIA Randomised clinical trials of benzodiazepine treatment in idiopathic RLS. DATA COLLECTION AND ANALYSIS We did not perform data collection and analysis, since we did not include any studies, MAIN RESULTS: We did not identify any studies that met the inclusion criteria of the review. Two cross-over studies are awaiting classification because the cross-over trials did not give data at the end of the first cross-over period. AUTHORS' CONCLUSIONS The effectiveness of benzodiazepines for RLS treatment is currently unknown.
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Affiliation(s)
- Karla Carlos
- Escola Paulista de Medicina, Universidade Federal de São PauloDepartment of NeurologySão PauloBrazil
| | - Gilmar F Prado
- Escola Paulista de Medicina, Universidade Federal de São PauloDepartment of NeurologySão PauloBrazil
| | - Camila DM Teixeira
- Escola Paulista de Medicina, Universidade Federal de São PauloDepartment of NeurologySão PauloBrazil
| | - Cristiane Conti
- Universidade Federal do MaranhãoDepartment of MorphologyAv. dos Portugueses, 1966BacangaSão LuisMaranhãoBrazil65080‐805
| | - Marcio M de Oliveira
- Universidade Federal do MaranhãoDepartment of MorphologyAv. dos Portugueses, 1966BacangaSão LuisMaranhãoBrazil65080‐805
| | - Lucila BF Prado
- Escola Paulista de Medicina, Universidade Federal de São PauloDepartment of NeurologySão PauloBrazil
| | - Luciane BC Carvalho
- Escola Paulista de Medicina, Universidade Federal de São PauloDepartment of NeurologySão PauloBrazil
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Connor JR, Patton SM, Oexle K, Allen RP. Iron and restless legs syndrome: treatment, genetics and pathophysiology. Sleep Med 2016; 31:61-70. [PMID: 28057495 DOI: 10.1016/j.sleep.2016.07.028] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 07/22/2016] [Accepted: 07/29/2016] [Indexed: 12/13/2022]
Abstract
In this article, we review the original findings from MRI and autopsy studies that demonstrated brain iron status is insufficient in individuals with restless legs syndrome (RLS). The concept of deficient brain iron status is supported by proteomic studies from cerebrospinal fluid (CSF) and from the clinical findings where intervention with iron, either dietary or intravenous, can improve RLS symptoms. Therefore, we include a section on peripheral iron status and how peripheral status may influence both the RLS symptoms and treatment strategy. Given the impact of iron in RLS, we have evaluated genetic data to determine if genes are directly involved in iron regulatory pathways. The result was negative. In fact, even the HFE mutation C282Y could not be shown to have a protective effect. Lastly, a consistent finding in conditions of low iron is increased expression of proteins in the hypoxia pathway. Although there is lack of clinical data that RLS patients are hypoxic, there are intriguing observations that environmental hypoxic conditions worsen RLS symptoms; in this chapter we review very compelling data for activation of hypoxic pathways in the brain in RLS patients. In general, the data in RLS point to a pathophysiology that involves decreased acquisition of iron by cells in the brain. Whether the decreased ability is genetically driven, activation of pathways (eg, hypoxia) that are designed to limit cellular uptake is unknown at this time; however, the data strongly support a functional rather than structural defect in RLS, suggesting that an effective treatment is possible.
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Affiliation(s)
- James R Connor
- Department of Neurosurgery, Penn State Hershey Medical Center, Hershey, PA, USA.
| | - Stephanie M Patton
- Department of Neurosurgery, Penn State Hershey Medical Center, Hershey, PA, USA
| | - Konrad Oexle
- Institut für Humangenetik, Technische Universität, Munich, Germany
| | - Richard P Allen
- The Johns Hopkins University, Dep of neuroloy, Baltimore, MD USA
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