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Ghahremanfard F, Semnani MR, Mirmohammadkhani M, Mansori K, Pahlevan D. The relationship between iron deficiency anemia with restless leg syndrome and sleep quality in workers working in a textile factory in Iran: a cross-sectional study. MIDDLE EAST CURRENT PSYCHIATRY 2023. [DOI: 10.1186/s43045-023-00294-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023] Open
Abstract
Abstract
Background
The aim of this study is to investigate the relationship between iron deficiency anemia with restless leg syndrome (RLS) and sleep quality in workers working in a textile factory in Iran. This cross-sectional study was conducted on 216 workers working in a textile factory in Iran. In addition to demographic and occupational variables, Pittsburgh Sleep Quality Index (PSQI) and RLS questionnaires were used for the data collection. To investigate iron deficiency anemia, 2 CC of blood was taken from the brachial artery with the help of a 10-CC syringe with a blue or pink tip. Then, relevant data were entered into SPSS26 and analyzed.
Results
The mean (S. D.) age of the workers was 32.23 (6.14) and 60.6% of them were women. The prevalence of iron deficiency anemia was 21.2 and 69.5% in men and women, respectively. Most of the workers were in moderate condition in terms of RLS severity, and 78.2% had sleep disorders. There was an inverse and significant correlation between age (β= −0.200), work experience (β= −0.160), hemoglobin (β= −0.149), and ferritin (β= −0.186) with global PSQI score (P value<0.05). Also, an inverse and significant correlation was observed between age (β= −0.164), hemoglobin (β= −0.548), and ferritin (β= −0.410) with RLS score (P value<0.05). However, there was a direct and significant correlation between TIBC level and RLS score (β= 0.227) and global PSQI score (β= 0.395) (P value<0.05).
Conclusions
Intervention programs to reduce iron deficiency anemia and periodic screening programs to identify sleep disorders and RLS in textile factory workers seem necessary.
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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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Khachatryan SG, Ferri R, Fulda S, Garcia‐Borreguero D, Manconi M, Muntean M, Stefani A. Restless legs syndrome: Over 50 years of European contribution. J Sleep Res 2022; 31:e13632. [PMID: 35808955 PMCID: PMC9542244 DOI: 10.1111/jsr.13632] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 04/21/2022] [Accepted: 04/22/2022] [Indexed: 11/28/2022]
Abstract
Restless legs syndrome (RLS) is a sensorimotor neurological disorder characterised by an urge to move the limbs with a circadian pattern (occurring in the evening/at night), more prominent at rest, and relieved with movements. RLS is one of the most prevalent sleep disorders, occurring in 5%-10% of the European population. Thomas Willis first described RLS clinical cases already in the 17th century, and Karl-Axel Ekbom described the disease as a modern clinical entity in the 20th century. Despite variable severity, RLS can markedly affect sleep (partly through the presence of periodic leg movements) and quality of life, with a relevant socio-economic impact. Thus, its recognition and treatment are essential. However, screening methods present limitations and should be improved. Moreover, available RLS treatment options albeit providing sustained relief to many patients are limited in number. Additionally, the development of augmentation with dopamine agonists represents a major treatment problem. A better understanding of RLS pathomechanisms can bring to light novel treatment possibilities. With emerging new avenues of research in pharmacology, imaging, genetics, and animal models of RLS, this is an interesting and constantly growing field of research. This review will update the reader on the current state of RLS clinical practice and research, with a special focus on the contribution of European researchers.
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Affiliation(s)
- Samson G. Khachatryan
- Department of Neurology and NeurosurgeryNational Institute of HealthYerevanArmenia
- Sleep Disorders CenterSomnus Neurology ClinicYerevanArmenia
| | | | - Stephany Fulda
- Sleep Medicine UnitNeurocenter of Southern Switzerland, Ospedale CivicoLuganoSwitzerland
| | | | - Mauro Manconi
- Sleep Medicine UnitNeurocenter of Southern Switzerland, Ospedale CivicoLuganoSwitzerland
- Department of NeurologyUniversity HospitalInselspitalBernSwitzerland
| | - Maria‐Lucia Muntean
- Center for Parkinson's Disease and Movement DisordersParacelsus‐Elena KlinikKasselGermany
| | - Ambra Stefani
- Sleep Disorders Clinic, Department of NeurologyMedical University of InnsbruckInnsbruckAustria
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Combining quantitative susceptibility mapping to radiomics in diagnosing Parkinson’s disease and assessing cognitive impairment. Eur Radiol 2022; 32:6992-7003. [DOI: 10.1007/s00330-022-08790-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 03/18/2022] [Accepted: 04/01/2022] [Indexed: 11/04/2022]
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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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Segura-Chama P, Luis E, Almanza A, Pellicer F, Hernández-Cruz A, Mercado F. Modulation of intracellular calcium concentration by D2-like DA receptor agonists in non-peptidergic DRG neurons is mediated mainly by D4 receptor activation. Neurosci Lett 2020; 736:135267. [PMID: 32717335 DOI: 10.1016/j.neulet.2020.135267] [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: 06/19/2020] [Revised: 07/10/2020] [Accepted: 07/20/2020] [Indexed: 10/23/2022]
Abstract
Nociceptive stimuli attributes are codified in the periphery; at this level, D2-like dopamine (DA) receptor activation decreases the high voltage-gated Ca2+ current predominantly in mechanonociceptive neurons, which explains the presynaptic action mechanism of the antinociception produced by quinpirole when it is intrathecally administered in rats. However, the identity of D2-like DA receptor subtype that mediates this effect remains unknown. To answer this question, we used Fluo-4-based Ca2+ microfluorometry to study the depolarization-elicited [Ca2+]i increase in small non-peptidergic DRG neurons (identified by its binding to the Isolectin B4), and to test the effect of D2-like DA receptor activation by quinpirole in presence of selective antagonists for D2, D3, and D4 DA receptors. The results showed a significantly greater contribution of the D4 DA receptor in the down-modulation of depolarization-elicited [Ca2+]i increase in small non-peptidergic DRG neurons compared to the other receptors. Although the D2 and D3 receptor antagonists also slightly inhibited the effect of quinpirole, their effects were significantly weaker than those of the D4 receptor antagonist. Furthermore, we showed that quinpirole selectively inhibits the CaV2.2 Ca2+ channels. Our results suggest that the activation of the D4 DA receptors is a promising strategy for pain management at the spinal cord level.
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Affiliation(s)
- Pedro Segura-Chama
- Laboratorio de Fisiología Celular, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Ciudad de México, Mexico; Cátedras CONACyT - Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Ciudad de México, Mexico
| | - Enoch Luis
- Laboratorio Nacional de Canalopatías, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico; Cátedras CONACyT - Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Angélica Almanza
- Laboratorio de Fisiología Celular, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Ciudad de México, Mexico
| | - Francisco Pellicer
- Laboratorio de Neurofisiología Integrativa, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Ciudad de México, Mexico
| | - Arturo Hernández-Cruz
- Laboratorio Nacional de Canalopatías, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico; Departamento de Neurociencia Cognitiva, División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Francisco Mercado
- Laboratorio de Fisiología Celular, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Ciudad de México, Mexico.
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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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8
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Lo Martire V, Alvente S, Bastianini S, Berteotti C, Valli A, Manconi M, Zoccoli G, Silvani A. Sleep and Tibialis Anterior Muscle Activity in Mice With Mild Hypoxia and Iron Deficiency: Implications for the Restless Legs Syndrome. Front Physiol 2018; 9:1818. [PMID: 30618828 PMCID: PMC6304696 DOI: 10.3389/fphys.2018.01818] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 12/05/2018] [Indexed: 12/14/2022] Open
Abstract
Restless legs syndrome (RLS) is a neurological disorder that entails an urge to move with a circadian pattern during the evening/night. RLS may be accompanied by decreased sleep time and increased occurrence of periodic leg movements during sleep (PLMS), which involve bursts of tibialis anterior (TA) muscle electromyogram (EMG). Mild hypoxia and non-anemic iron deficiency, a highly prevalent nutritional deficiency, are relatively unexplored factors in RLS pathophysiology. We tested whether mice exposed to mild hypoxia, alone or in combination with non-anemic iron deficiency, show decreased sleep time particularly in the light (rest) period and increased occurrence of TA EMG phasic events similar to human PLMS. Female C57BL/6J mice were fed diets with low or normal iron for 6 months from weaning and instrumented with electrodes to record the electroencephalogram and the EMG of both TA muscles. Mice were recorded in a whole-body plethysmograph while breathing a normoxic or mildly hypoxic (15% O2) gas mixture for 48 h. Hypoxia increased minute ventilation during sleep. The low-iron diet decreased liver and serum iron, leaving blood hemoglobin and brainstem iron levels unaffected. Hypoxia, either alone or in combination with non-anemic iron deficiency, decreased non-rapid-eye-movement (non-REM) sleep time, but this occurred irrespective of the light/dark period and was not associated with increased occurrence of TA EMG events during non-REM sleep. These results do not support the hypothesis that mild hypoxia is sufficient to cause signs of RLS, either alone or in combination with non-anemic iron deficiency, pointing to the necessity of further susceptibility factors.
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Affiliation(s)
- Viviana Lo Martire
- Laboratory of Physiological Regulations in Sleeping Mice, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Sara Alvente
- Laboratory of Physiological Regulations in Sleeping Mice, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Stefano Bastianini
- Laboratory of Physiological Regulations in Sleeping Mice, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Chiara Berteotti
- Laboratory of Physiological Regulations in Sleeping Mice, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Alice Valli
- Laboratory of Physiological Regulations in Sleeping Mice, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Mauro Manconi
- Sleep and Epilepsy Center, Neurocenter of Southern Switzerland, Civic Hospital (EOC) of Lugano, Lugano, Switzerland.,Department of Neurology, Bern University Hospital, Bern, Switzerland
| | - Giovanna Zoccoli
- Laboratory of Physiological Regulations in Sleeping Mice, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Alessandro Silvani
- Laboratory of Physiological Regulations in Sleeping Mice, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
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Yamada Y, Prosser RA. Copper in the suprachiasmatic circadian clock: A possible link between multiple circadian oscillators. Eur J Neurosci 2018; 51:47-70. [PMID: 30269387 DOI: 10.1111/ejn.14181] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 09/05/2018] [Accepted: 09/17/2018] [Indexed: 01/07/2023]
Abstract
The mammalian circadian clock in the suprachiasmatic nucleus (SCN) is very robust, able to coordinate our daily physiological and behavioral rhythms with exquisite accuracy. Simultaneously, the SCN clock is highly sensitive to environmental timing cues such as the solar cycle. This duality of resiliency and sensitivity may be sustained in part by a complex intertwining of three cellular oscillators: transcription/translation, metabolic/redox, and membrane excitability. We suggest here that one of the links connecting these oscillators may be forged from copper (Cu). Cellular Cu levels are highly regulated in the brain and peripherally, and Cu affects cellular metabolism, redox state, cell signaling, and transcription. We have shown that both Cu chelation and application induce nighttime phase shifts of the SCN clock in vitro and that these treatments affect glutamate, N-methyl-D-aspartate receptor, and associated signaling processes differently. More recently we found that Cu induces mitogen-activated protein kinase-dependent phase shifts, while the mechanisms by which Cu removal induces phase shifts remain unclear. Lastly, we have found that two Cu transporters are expressed in the SCN, and that one of these transporters (ATP7A) exhibits a day/night rhythm. Our results suggest that Cu homeostasis is tightly regulated in the SCN, and that changes in Cu levels may serve as a time cue for the circadian clock. We discuss these findings in light of the existing literature and current models of multiple coupled circadian oscillators in the SCN.
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Affiliation(s)
- Yukihiro Yamada
- Department of Biochemistry & Cellular and Molecular Biology, NeuroNET Research Center, University of Tennessee, Knoxville, Tennessee
| | - Rebecca A Prosser
- Department of Biochemistry & Cellular and Molecular Biology, NeuroNET Research Center, University of Tennessee, Knoxville, Tennessee
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Meneely S, Dinkins ML, Kassai M, Lyu S, Liu Y, Lin CT, Brewer K, Li Y, Clemens S. Differential Dopamine D1 and D3 Receptor Modulation and Expression in the Spinal Cord of Two Mouse Models of Restless Legs Syndrome. Front Behav Neurosci 2018; 12:199. [PMID: 30233336 PMCID: PMC6131574 DOI: 10.3389/fnbeh.2018.00199] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 08/13/2018] [Indexed: 12/22/2022] Open
Abstract
Restless Legs Syndrome (RLS) is often and successfully treated with dopamine receptor agonists that target the inhibitory D3 receptor subtype, however there is no clinical evidence of a D3 receptor dysfunction in RLS patients. In contrast, genome-wide association studies in RLS patients have established that a mutation of the MEIS1 gene is associated with an increased risk in developing RLS, but the effect of MEIS1 dysfunction on sensorimotor function remain unknown. Mouse models for a dysfunctional D3 receptor (D3KO) and Meis1 (Meis1KO) were developed independently, and each animal expresses some features associated with RLS in the clinic, but they have not been compared in their responsiveness to treatment options used in the clinic. We here confirm that D3KO and Meis1KO animals show increased locomotor activities, but that only D3KO show an increased sensory excitability to thermal stimuli. Next we compared the effects of dopaminergics and opioids in both animal models, and we assessed D1 and D3 dopamine receptor expression in the spinal cord, the gateway for sensorimotor processing. We found that Meis1KO share most of the tested behavioral properties with their wild type (WT) controls, including the modulation of the thermal pain withdrawal reflex by morphine, L-DOPA and D3 receptor (D3R) agonists and antagonists. However, Meis1KO and D3KO were behaviorally more similar to each other than to WT when tested with D1 receptor (D1R) agonists and antagonists. Subsequent Western blot analyses of D1R and D3R protein expression in the spinal cord revealed a significant increase in D1R but not D3R expression in Meis1KO and D3KO over WT controls. As the D3R is mostly present in the dorsal spinal cord where it has been shown to modulate sensory pathways, while activation of the D1Rs can activate motoneurons in the ventral spinal cord, we speculate that D3KO and Meis1KO represent two complementary animal models for RLS, in which the mechanisms of sensory (D3R-mediated) and motor (D1R-mediated) dysfunctions can be differentially explored.
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Affiliation(s)
- Samantha Meneely
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
| | - Mai-Lynne Dinkins
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
| | - Miki Kassai
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
| | - Shangru Lyu
- Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, United States
| | - Yuning Liu
- Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, United States
| | - Chien-Te Lin
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
- East Carolina Diabetes and Obesity Institute, Brody School of Medicine, East Carolina University, Greenville, NC, United States
| | - Kori Brewer
- Department of Emergency Medicine, Brody School of Medicine, East Carolina University, Greenville, NC, United States
| | - Yuqing Li
- Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, United States
- Wuxi Medical School, Jiangnan University, Wuxi, China
| | - Stefan Clemens
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
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Motonishi S, Tanaka K, Ozawa T. Iron deficiency associates with deterioration in several symptoms independently from hemoglobin level among chronic hemodialysis patients. PLoS One 2018; 13:e0201662. [PMID: 30071093 PMCID: PMC6072073 DOI: 10.1371/journal.pone.0201662] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 07/19/2018] [Indexed: 12/22/2022] Open
Abstract
Background While iron deficiency (ID) is a frequent cause of anemia in hemodialysis patients, the clinical impact of ID without anemic level of hemoglobin remains unclear. As such, this study was designed to clarify the manifestations of ID itself in subjects on hemodialysis. Methods Maintenance hemodialysis patients achieving target hemoglobin levels (≥ 10.0g/dL) under treatment in our clinic were stratified for comparison from three perspectives: ID (transferrin saturation [TSAT] < 20% or ferritin < 100ng/mL) vs non-ID, level of TSAT (< or ≥ 20%), and level of serum ferritin concentration (< or ≥ 100ng/mL). The severity of frequent symptoms was determined by a self-rating symptom score questionnaire, and the rate of those with severe manifestations was calculated for each symptom. Significant difference was examined between groups; univariate and adjusted multivariate odds ratios and 95% confidence intervals were obtained by logistic regression. Results Among 154 subjects selected for analysis, the ratio of severe arthralgia and fatigue was significantly higher in the ID group (n = 94) compared to the non-ID group (n = 60), in both univariate and adjusted multivariate analyses. Moreover, in multivariate analysis, low TSAT was significantly associated with exacerbation of pain during vascular access puncture and intradialytic leg cramps, while low serum ferritin concentration was related to significant increase in severe arthralgia, fatigue, intradialytic headache and leg cramps. Conclusions ID was identified as a risk factor regarding severity of several symptoms even without low hemoglobin level among chronic hemodialysis patients, and supplementation of iron was considered efficacious for improving critical symptoms affecting those undergoing maintenance dialysis.
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Peters AEJ, van Silfhout L, Graco M, Schembri R, Thijssen D, Berlowitz DJ. Periodic limb movements in tetraplegia. J Spinal Cord Med 2018; 41:318-325. [PMID: 28464758 PMCID: PMC6055951 DOI: 10.1080/10790268.2017.1320874] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
OBJECTIVE To establish the prevalence of Periodic Limb Movements during Sleep (PLMS) in patients with tetraplegia, controlling for obstructive sleep apnea. To explore whether demographic and injury characteristics affect PLMS. STUDY DESIGN Retrospective cohorts. SETTING AND PARTICIPANTS One hundred seventy-three participants with acute (<12 months) and 92 with chronic (>12 months) tetraplegia who underwent full overnight diagnostic sleep studies. INTERVENTIONS AND OUTCOME MEASURES Two hundred sixty-two sleep study recordings were included. A randomly selected subgroup of 21 studies was assessed for PLM during wakefulness. Data were analysed according to the current American Academy of Sleep Medicine guidelines. RESULTS Of the participants, 41.6% (43(15.7) years and 14.9% female) had a motor and sensory complete lesion. Sleep was poor with both OSA (87.8% with apnea hypopnoea index ≥ 5) and PLMS (58.4% with PLMS per hour PLMSI > 15) highly prevalent. There was no difference in the PLMSI between those with OSA (36.3(39.8)) or without (42.2(37.7), P = 0.42). PLMS were evident during REM and NREM sleep in all of the 153 patients with PLMSI > 15. All 21 participants in the subgroup of studies analysed for the PLM during quiet wakefulness, exhibited limb movements. None of the modelled variables (injury completeness, gender, OSA severity or time since injury) significantly predicted a PLMSI > 15 (P = 0.343). CONCLUSION In conclusion, this study confirms the high prevalence of PLM in tetraplegia and the presence of leg movements in NREM and REM sleep along with wakefulness after controlling for OSA. No associations between the presence of PLMS and patient characteristics or injury specific aspects were found.
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Affiliation(s)
- Annemieke Emma Josina Peters
- a Institute for Breathing and Sleep , Austin Health , Melbourne , Australia.,b Department of Physiology , Radboud University Nijmegen Medical Centre , Nijmegen , The Netherlands
| | - Lysanne van Silfhout
- a Institute for Breathing and Sleep , Austin Health , Melbourne , Australia.,b Department of Physiology , Radboud University Nijmegen Medical Centre , Nijmegen , The Netherlands
| | - Marnie Graco
- a Institute for Breathing and Sleep , Austin Health , Melbourne , Australia
| | - Rachel Schembri
- a Institute for Breathing and Sleep , Austin Health , Melbourne , Australia
| | - Dick Thijssen
- a Institute for Breathing and Sleep , Austin Health , Melbourne , Australia
| | - David J Berlowitz
- a Institute for Breathing and Sleep , Austin Health , Melbourne , Australia
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Silvani A, Manconi M, Ferri R. The iron-deficient rat as a model of restless legs syndrome: Was anything lost in translation? Mov Disord 2017; 33:181. [PMID: 29219205 DOI: 10.1002/mds.27264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 11/08/2017] [Indexed: 11/09/2022] Open
Affiliation(s)
- Alessandro Silvani
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Mauro Manconi
- Sleep and Epilepsy Center, Neurocenter of Southern Switzerland, Civic Hospital (EOC) of Lugano, Lugano, Switzerland.,Department of Neurology, Bern University Hospital, Bern, Switzerland
| | - Raffaele Ferri
- Sleep Research Centre, Department of Neurology I.C., Oasi Institute for Research on Mental Retardation and Brain Aging (IRCCS), Troina, Italy
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15
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Angriman M, Cortese S, Bruni O. Somatic and neuropsychiatric comorbidities in pediatric restless legs syndrome: A systematic review of the literature. Sleep Med Rev 2017; 34:34-45. [DOI: 10.1016/j.smrv.2016.06.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Revised: 05/18/2016] [Accepted: 06/22/2016] [Indexed: 11/26/2022]
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16
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Lanza G, Bachmann CG, Ghorayeb I, Wang Y, Ferri R, Paulus W. Central and peripheral nervous system excitability in restless legs syndrome. Sleep Med 2017; 31:49-60. [PMID: 27745789 DOI: 10.1016/j.sleep.2016.05.010] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 05/24/2016] [Accepted: 05/30/2016] [Indexed: 02/07/2023]
Abstract
Neurophysiological techniques have been applied in restless legs syndrome (RLS) to obtain direct and indirect measures of central and peripheral nervous system excitability, as well as to probe different neurotransmission pathways. Data converge on the hypothesis that, from a pure electrophysiological perspective, RLS should be regarded as a complex sensorimotor disorder in which cortical, subcortical, spinal cord, and peripheral nerve generators are all involved in a network disorder, resulting in an enhanced excitability and/or decreased inhibition. Although the spinal component may have dominated in neurophysiological assessment, possibly because of better accessibility compared to the brainstem or cerebral components of a hypothetical dysfunction of the diencephalic A11 area, multiple mechanisms, such as reduced central inhibition and abnormal peripheral nerve function, contribute to the pathogenesis of RLS similarly to some chronic pain conditions. Dopamine transmission dysfunction, either primary or triggered by low iron and ferritin concentrations, may also bridge the gap between RLS and chronic pain entities. Further support of disturbed central and peripheral excitability in RLS is provided by the effectiveness of nonpharmacological tools, such as repetitive transcranial magnetic stimulation and transcutaneous spinal direct current stimulation, in transiently modulating neural excitability, thereby extending the therapeutic repertoire. Understanding the complex interaction of central and peripheral neuronal circuits in generating the symptoms of RLS is mandatory for a better refinement of its therapeutic support.
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Affiliation(s)
- Giuseppe Lanza
- Sleep Research Center, I.R.C.C.S. "Oasi Maria SS.", Troina, Italy.
| | | | - Imad Ghorayeb
- Department of Clinical Neurophysiology, CHU de Bordeaux, Bordeaux, France; CNRS, INCIA, CNRS UMR 5287, Université de Bordeaux, Bordeaux, France
| | - Yuping Wang
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Raffale Ferri
- Sleep Research Center, I.R.C.C.S. "Oasi Maria SS.", Troina, Italy
| | - Walter Paulus
- Department of Clinical Neurophysiology, University Medical Center, Georg August University Göttingen, Göttingen, Germany
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17
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Khan FH, Ahlberg CD, Chow CA, Shah DR, Koo BB. Iron, dopamine, genetics, and hormones in the pathophysiology of restless legs syndrome. J Neurol 2017; 264:1634-1641. [PMID: 28236139 DOI: 10.1007/s00415-017-8431-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 02/16/2017] [Accepted: 02/18/2017] [Indexed: 12/16/2022]
Abstract
Restless legs syndrome (RLS) is a common, chronic neurologic condition, which causes a persistent urge to move the legs in the evening that interferes with sleep. Human and animal studies have been used to study the pathophysiologic state of RLS and much has been learned about the iron and dopamine systems in relation to RLS. Human neuropathologic and imaging studies have consistently shown decreased iron in different brain regions including substantia nigra and thalamus. These same areas also demonstrate a state of relative dopamine excess. While it is not known how these changes in dopamine or iron produce the symptoms of RLS, genetic and hormone studies of RLS have identified other biologic systems or genes, such as the endogenous opioid and melanocortin systems and BTBD9 and MEIS1, that may explain some of the iron or dopamine changes in relation to RLS. This manuscript will review what is known about the pathophysiology of RLS, especially as it relates to changes in iron, dopamine, genetics, and hormonal systems.
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Affiliation(s)
- Farhan H Khan
- Lippard Laboratory of Clinical Investigation, Division of Movement Disorders, Department of Neurology, Yale University School of Medicine, Room 710, West Haven VAMC, 950 Campbell Avenue, West Haven, CT, 06516, USA
| | - Caitlyn D Ahlberg
- Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Christopher A Chow
- Lippard Laboratory of Clinical Investigation, Division of Movement Disorders, Department of Neurology, Yale University School of Medicine, Room 710, West Haven VAMC, 950 Campbell Avenue, West Haven, CT, 06516, USA
| | - Divya R Shah
- Lippard Laboratory of Clinical Investigation, Division of Movement Disorders, Department of Neurology, Yale University School of Medicine, Room 710, West Haven VAMC, 950 Campbell Avenue, West Haven, CT, 06516, USA
| | - Brian B Koo
- Lippard Laboratory of Clinical Investigation, Division of Movement Disorders, Department of Neurology, Yale University School of Medicine, Room 710, West Haven VAMC, 950 Campbell Avenue, West Haven, CT, 06516, USA.
- Connecticut Veterans Affairs Medical Center, 950 Campbell Avenue, West Haven, CT, 06516, USA.
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18
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Lin CC, Fan YM, Lin GY, Yang FC, Cheng CA, Lu KC, Lin JC, Lee JT. 99mTc-TRODAT-1 SPECT as a Potential Neuroimaging Biomarker in Patients With Restless Legs Syndrome. Clin Nucl Med 2016. [PMID: 26204215 DOI: 10.1097/rlu.0000000000000916] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Restless legs syndrome (RLS) is a neurological sensory motor disorder of which pathophysiology remains sketchy. The present study was aimed to determine the diagnostic accuracy and potential of SPECT-TRODAT imaging in discriminating patients with RLS from normal individuals. PATIENTS AND METHODS A total of 34 subjects, 22 diagnosed with RLS and 12 classified as normal, were enrolled. Brain SPECT images were acquired 180 minutes after IV injection of 740 to 925 MBq (20-25 mCi) 99mTc-TRODAT-1 using a double-headed γ-camera equipped with high-resolution fan-beam collimators. Regions of interest were drawn over the whole striatum, caudate, and putamen nucleus of each hemisphere on composite images of the 9 slices with the highest basal ganglia activity. The brain SPECT 99mTc-TRODAT-1 imaging was compared with early-stage RLS patients and healthy volunteers groups. RESULT SPECT imaging in RLS patients showed reduced radioactivity accumulation in the striatum profile. The major abnormal result observed is the significantly reduced uptake in striatal dopamine transporter density and activity. The symmetric striatal uptake was observed, and striatum dopamine transporter destiny was more impaired in patients with RLS disease. SPECT images also showed significant differences between patients and volunteers. CONCLUSIONS This study supports that symptoms of restless legs resulted from the striatum of the brain dopaminergic system dysfunction.
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Affiliation(s)
- Chun-Chieh Lin
- From the *Department of Neurology, Tri-Service General Hospital, National Defense Medical Center, Taipei; †Department of Nuclear Medicine, Cardinal Tien Hospital, New Taipei City; ‡School of Medicine, Fu-Jen Catholic University, Taipei; §Division of Nephrology, Department of Medicine, Cardinal Tien Hospital, New Taipei City; and ∥Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan
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Keeler BE, Lallemand P, Patel MM, de Castro Brás LE, Clemens S. Opposing aging-related shift of excitatory dopamine D1 and inhibitory D3 receptor protein expression in striatum and spinal cord. J Neurophysiol 2015; 115:363-9. [PMID: 26561599 DOI: 10.1152/jn.00390.2015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 11/06/2015] [Indexed: 12/18/2022] Open
Abstract
Normal aging is associated with a decrease in motor function, a concomitant increase in muscle stiffness and tone, and a decrease in dopamine (DA) levels in the spinal cord. The striatum plays a critical role in the control of motor function, and it receives strong DA innervation from the substantia nigra. However, locomotor activity also requires the activation of motoneurons in the lumbar spinal cord, which in the mouse express all five DA receptor subtypes (D1-D5). Of these, the D3 receptor (D3R) expresses the highest affinity to DA and mediates inhibitory actions, while activation of the lower-affinity D1 receptor (D1R) system promotes excitatory effects. To test whether the aging-related decrease in DA levels is associated with corresponding changes in DA receptor protein expression levels, we probed with Western blot and immunohistochemical techniques for D1R and D3R protein expression levels over the normal life span of the mouse. We found that with age D1R expression levels increased in both striatum and spinal cord, while D3R expression levels remained stable in the striatum or slightly decreased in the spinal cord. The resulting D1-to-D3 ratio indicates a strong upregulation of D1R-mediated pathways in old animals, which is particularly pronounced in the lumbar spinal cord. These data suggest that aging may be associated with a shift in DA-mediated pathways in striatum and spinal cord, which in turn could be an underlying factor in the emergence of aging- and DA-related motor dysfunctions such as Parkinson's disease or Restless Legs Syndrome (RLS).
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Affiliation(s)
- Benjamin E Keeler
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina
| | - Perrine Lallemand
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina
| | - Mukund M Patel
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina
| | - Lisandra E de Castro Brás
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina
| | - Stefan Clemens
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina
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20
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Papageorgiou V, Vargiami E, Kontopoulos E, Kardaras P, Economou M, Athanassiou-Mataxa M, Kirkham F, Zafeiriou DI. Association between iron deficiency and febrile seizures. Eur J Paediatr Neurol 2015; 19:591-6. [PMID: 26112262 DOI: 10.1016/j.ejpn.2015.05.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 05/03/2015] [Accepted: 05/25/2015] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The relationship between iron status and febrile seizures has been examined in various settings, mainly in the Developing World, with conflicting results. The aim of this study was to investigate any association between iron deficiency and febrile seizures (FS) in European children aged 6-60 months. DESIGN Prospective, case-control study. SETTING Greek population in Thessaloniki. PATIENTS 50 patients with febrile seizures (cases) and 50 controls (children presenting with fever, without seizures). INTERVENTIONS None. MAIN OUTCOME MEASURES Haematologic parameters (haemoglobin concentration, haematocrit, mean corpuscular volume, red cell distribution width), plasma iron, total iron-binding capacity, plasma ferritin, transferrin saturation and soluble transferrin receptors were compared in cases and controls. RESULTS Plasma ferritin was lower (median [range]: 42.8 (3-285.7) vs 58.3 (21.4-195.3 ng/ml; p = 0.02) and Total Iron Binding Capacity (TIBC) higher (mean [Standard Deviation] 267 [58.9] vs 243 [58.45] μg/dl, p = 0.04) in cases than in controls. Results were similar for 12 complex FS cases (ferritin 30 (3-121 vs 89 (41.8-141.5ng/lL; TIBC 292.92 [68.0] vs 232.08 [36.27] μg/dL). Iron deficiency, defined as ferritin <30 ng/ml, was more frequent in cases (24%) than controls (4%; p = 0.004). Ferritin was lower and TIBC higher in 18 with previous seizures than in 32 with a first seizure although haemoglobin and mean cell haemoglobin concentration were higher. CONCLUSIONS European children with febrile seizures have lower Ferritin than those with fever alone, and iron deficiency, but not anaemia, is associated with recurrence. Iron status screening should be considered as routine for children presenting with or at high risk for febrile seizures.
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Affiliation(s)
- Valia Papageorgiou
- 1st Department of Pediatrics, Aristotle University of Thessaloniki, Hippokratio General Hospital, Thessaloniki, Greece
| | - Euthymia Vargiami
- 1st Department of Pediatrics, Aristotle University of Thessaloniki, Hippokratio General Hospital, Thessaloniki, Greece
| | - Eleutherios Kontopoulos
- 1st Department of Pediatrics, Aristotle University of Thessaloniki, Hippokratio General Hospital, Thessaloniki, Greece
| | - Panagiotis Kardaras
- 3rd Department of Pediatrics, Aristotle University of Thessaloniki, Hippokratio General Hospital, Thessaloniki, Greece
| | - Marina Economou
- 1st Department of Pediatrics, Aristotle University of Thessaloniki, Hippokratio General Hospital, Thessaloniki, Greece
| | - Miranta Athanassiou-Mataxa
- 1st Department of Pediatrics, Aristotle University of Thessaloniki, Hippokratio General Hospital, Thessaloniki, Greece
| | - Fenella Kirkham
- Division of Clinical and Experimental Sciences, University of Southampton, UK; Neurosciences Unit, UCL Institute of Child Health, London, UK
| | - Dimitrios I Zafeiriou
- 1st Department of Pediatrics, Aristotle University of Thessaloniki, Hippokratio General Hospital, Thessaloniki, Greece.
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21
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Klinker F, Liebetanz D. Combined D3 Receptor/Iron-Deficient Mouse Model. Mov Disord 2015. [DOI: 10.1016/b978-0-12-405195-9.00077-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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23
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Sleep disorders: A review of the interface between restless legs syndrome and iron metabolism. ACTA ACUST UNITED AC 2014; 7:234-7. [PMID: 26483934 PMCID: PMC4608891 DOI: 10.1016/j.slsci.2014.10.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 10/13/2014] [Accepted: 10/15/2014] [Indexed: 11/23/2022]
Abstract
Restless legs syndrome (RLS) is characterized by unpleasant sensations mainly in the legs. 43% of RLS-associated conditions have also been associated with systemic iron deficiency. The objective of this study was to review in the literature the relationship between iron metabolism and RLS. With an initial search using the keywords combination “Iron Metabolism OR Iron Deficiency AND Restless Legs Syndrome,” 145 articles were screened, and 20 articles were selected. Few studies were found for this review in the period of 2001–2014, however, the correlation between RLS and iron was evident.
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24
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Schulte EC, Kaffe M, Schormair B, Winkelmann J. Iron in Restless Legs Syndrome. Mov Disord Clin Pract 2014; 1:161-172. [PMID: 30363981 DOI: 10.1002/mdc3.12047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 04/07/2014] [Accepted: 04/18/2014] [Indexed: 12/14/2022] Open
Abstract
A link between restless legs syndrome (RLS) and iron has been recognized for several decades. Yet, the precise role that iron or other components of iron metabolism play in bringing about RLS is still a matter of debate. During the last few years, many new pieces of evidence from genetics, pathology, imaging, and clinical studies have surfaced. However, the way this evidence fits into the larger picture of RLS as a disease is not always easily understood. To provide a better understanding of the complex interplay between iron metabolism and RLS and highlight areas that need further elucidation, we systematically and critically review the current literature on the role of iron in RLS pathophysiology and treatment with a special emphasis on genetics, neuropathology, cell and animal models, imaging studies, and therapy.
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Affiliation(s)
- Eva C Schulte
- Neurologische Klinik und Poliklinik Klinikum rechts der Isar Technische Universität München Munich Germany.,Institut für Humangenetik Helmholtz Zentrum München Munich Germany.,Institut für Humangenetik Klinikum rechts der Isar Technische Universität München Munich Germany
| | - Maria Kaffe
- Neurologische Klinik und Poliklinik Klinikum rechts der Isar Technische Universität München Munich Germany.,Institut für Humangenetik Klinikum rechts der Isar Technische Universität München Munich Germany
| | - Barbara Schormair
- Institut für Humangenetik Helmholtz Zentrum München Munich Germany.,Institut für Humangenetik Klinikum rechts der Isar Technische Universität München Munich Germany
| | - Juliane Winkelmann
- Neurologische Klinik und Poliklinik Klinikum rechts der Isar Technische Universität München Munich Germany.,Institut für Humangenetik Helmholtz Zentrum München Munich Germany.,Institut für Humangenetik Klinikum rechts der Isar Technische Universität München Munich Germany.,Munich Cluster for Systems Neurology (SyNergy) Munich Germany
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Jung JS, Lee HJ, Cho CH, Kang SG, Yoon HK, Park YM, Moon JH, Yang HJ, Song HM, Kim L. Association between restless legs syndrome and CLOCK and NPAS2 gene polymorphisms in schizophrenia. Chronobiol Int 2014; 31:838-44. [PMID: 24824748 DOI: 10.3109/07420528.2014.914034] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Previous studies have suggested that there is a genetic basis to restless legs syndrome (RLS) development. Occurrence of antipsychotic-induced RLS could also be due to differences in genetic susceptibility. We investigated whether CLOCK and NPAS2 gene polymorphisms are associated with RLS in schizophrenic patients on antipsychotics because RLS symptoms usually manifest during the evening and night. We assessed symptoms of RLS in 190 Korean schizophrenic patients on antipsychotics and divided the subjects into two groups according to the International Restless Legs Syndrome Study Group diagnostic criteria: (i) subjects who met all the criteria and (ii) the remaining subjects who did not meet all the criteria. We found a significant difference in the number of subjects with different genotype and allele carrier frequencies for the CLOCK gene (rs2412646) between the two groups (p = 0.031 and 0.010, respectively). Distribution of CLOCK haplotypes (rs2412646-rs1801260) was significantly different between schizophrenic patients with and without RLS (p = 0.021). However, the distributions of allelic, genotypic, and haplotypic variants of NPAS2 (rs2305160 and rs6725296) were not significantly different between the two groups. Our results suggest that CLOCK polymorphisms are associated with increased susceptibility of schizophrenic patients to RLS. We hypothesize that RLS in schizophrenia patients treated with antipsychotics may be a very mild akathisia that manifests during the night and is under control of circadian oscillation.
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Affiliation(s)
- Jin-Sook Jung
- Department of Psychiatry, College of Medicine, Korea University , Seoul , South Korea
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26
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Toth LA, Bhargava P. Animal models of sleep disorders. Comp Med 2013; 63:91-104. [PMID: 23582416 PMCID: PMC3625050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 10/21/2012] [Accepted: 11/25/2012] [Indexed: 06/02/2023]
Abstract
Problems with sleep affect a large part of the general population, with more than half of all people in the United States reporting difficulties with sleep or insufficient sleep at various times and about 40 million affected chronically. Sleep is a complex physiologic process that is influenced by many internal and environmental factors, and problems with sleep are often related to specific personal circumstances or are based on subjective reports from the affected person. Although human subjects are used widely in the study of sleep and sleep disorders, the study of animals has been invaluable in developing our understanding about the physiology of sleep and the underlying mechanisms of sleep disorders. Historically, the use of animals for the study of sleep disorders has arguably been most fruitful for the condition of narcolepsy, in which studies of dogs and mice revealed previously unsuspected mechanisms for this condition. The current overview considers animal models that have been used to study 4 of the most common human sleep disorders-insomnia, narcolepsy, restless legs syndrome, and sleep apnea-and summarizes considerations relevant to the use of animals for the study of sleep and sleep disorders. Animal-based research has been vital to the elucidation of mechanisms that underlie sleep, its regulation, and its disorders and undoubtedly will remain crucial for discovering and validating sleep mechanisms and testing interventions for sleep disorders.
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Affiliation(s)
- Linda A Toth
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, Illinois, USA.
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27
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Jiménez-Jiménez FJ, Alonso-Navarro H, Martínez C, Zurdo M, Turpín-Fenoll L, Millán J, Adeva-Bartolomé T, Cubo E, Navacerrada F, Calleja M, Plaza-Nieto JF, Pilo-de-la-Fuente B, Arroyo-Solera M, Rojo-Sebastián A, Rubio L, Agúndez JAG, García-Martín E. Dopamine receptor D3 (DRD3) gene rs6280 variant and risk for restless legs syndrome. Sleep Med 2013; 14:382-4. [PMID: 23312624 DOI: 10.1016/j.sleep.2012.11.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 11/04/2012] [Accepted: 11/20/2012] [Indexed: 11/18/2022]
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28
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Freeman AAH, Mandilaras K, Missirlis F, Sanyal S. An emerging role for Cullin-3 mediated ubiquitination in sleep and circadian rhythm: insights from Drosophila. Fly (Austin) 2013; 7:39-43. [PMID: 23455037 DOI: 10.4161/fly.23506] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Although the neurophysiological correlates of sleep have been thoroughly described, genetic mechanisms that control sleep architecture, long surmised from ethological studies, family histories and clinical observations, have only been investigated during the past decade. Key contributions to the molecular understanding of sleep have come from studies in Drosophila, benefitting from a strong history of circadian rhythm research. For instance, a number of recent papers have highlighted the role of the E3 ubiquitin ligase Cullin-3 in the regulation of circadian rhythm and sleep. We propose that different Cullin-3 substrate adaptors may affect specific molecular pathways and diverse aspects of circadian rhythm and sleep. We have previously shown that mutations in BTBD9, a risk factor for Restless Legs Syndrome (RLS) encoding a Cullin-3 substrate adaptor, lead to reduced dopamine, increased locomotion and sleep fragmentation. Here, we propose that Cullin-3 acts together with BTBD9 to limit the accumulation of iron regulatory proteins in conditions of iron deficiency. Our model is consistent with clinical observations implicating iron homeostasis in the pathophysiology of RLS and predicts that lack of BTBD9 leads to misregulation of cellular iron storage, inactivating the critical biosynthetic enzyme Tyrosine Hydroxylase in dopaminergic neurons, with consequent phenotypic effects on sleep.
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Affiliation(s)
- Amanda A H Freeman
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA.
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29
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Keeler BE, Baran CA, Brewer KL, Clemens S. Increased excitability of spinal pain reflexes and altered frequency-dependent modulation in the dopamine D3-receptor knockout mouse. Exp Neurol 2012; 238:273-83. [DOI: 10.1016/j.expneurol.2012.09.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 08/22/2012] [Accepted: 09/09/2012] [Indexed: 12/29/2022]
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30
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Direct and indirect interactions of the dopamine D₃ receptor with glutamate pathways: implications for the treatment of schizophrenia. Naunyn Schmiedebergs Arch Pharmacol 2012; 386:107-24. [PMID: 23001156 PMCID: PMC3558669 DOI: 10.1007/s00210-012-0797-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Accepted: 09/03/2012] [Indexed: 12/24/2022]
Abstract
This article, based on original data as well as on previously reported preclinical and clinical data that are reviewed, describes direct and indirect interactions of the D(3) receptor with N-methyl-D-aspartate receptor (NMDA) signaling and their functional consequences and therapeutic implications for schizophrenia. D(3) receptor immunoreactivity at ultrastructural level with electron microscopy was identified at presumably glutamatergic, asymmetric synapses of the medium-sized spiny neurons of the nucleus accumbens. This finding supports the existence of a direct interaction of the D(3) receptor with glutamate, in line with previously described interactions with NMDA signaling involving Ca(2+)/calmodulin-dependent protein kinase II at post-synaptic densities (Liu et al. 2009). Indirect interactions of the D(3) receptor with glutamate could involve a negative control exerted by the D(3) receptor on mesocortical dopamine neurons and the complex regulation of the glutamatergic pyramidal cells by dopamine in the prefrontal cortex. This could be exemplified here by the regulation of pyramidal cell activity in conditions of chronic NMDA receptor blockade with dizocilpine (MK-801). BP897, a D(3) receptor-selective partial agonist, reversed the dysregulation of cortical c-fos mRNA expression and pyramidal cell hyperexcitability, as measured by paired-pulse electrophysiology. At the behavioral level, blockade of the D(3) receptor, by known D(3) receptor antagonists or the novel D(3) receptor-selective antagonist F17141, produces antipsychotic-like effects in reversing hyperactivity and social interaction deficits induced by NMDA receptor blockade by MK-801 in mice. The glutamate-D(3) receptor interactions described here offer a conceptual framework for developing new D(3) receptor-selective drugs, which may appear as an original, efficacious, and safe way to potentially indirectly target glutamate in schizophrenia.
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31
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DeAndrade MP, Johnson RL, Unger EL, Zhang L, van Groen T, Gamble KL, Li Y. Motor restlessness, sleep disturbances, thermal sensory alterations and elevated serum iron levels in Btbd9 mutant mice. Hum Mol Genet 2012; 21:3984-92. [PMID: 22678064 DOI: 10.1093/hmg/dds221] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Restless legs syndrome (RLS), also known as Willis-Ekbom disease, is a sensory-motor neurological disorder with a circadian component. RLS is characterized by uncomfortable sensations in the extremities, generally at night or during sleep, which often leads to an uncontrollable urge to move them for relief. Recently, genomic studies identified single-nucleotide polymorphisms in BTBD9, along with three other genes, as being associated with a higher risk of RLS. Little is known about the function of BTBD9 or its potential role in the pathophysiology of RLS. We therefore examined a line of Btbd9 mutant mice we recently generated for phenotypes similar to symptoms found in RLS patients. We observed that the Btbd9 mutant mice had motor restlessness, sensory alterations likely limited to the rest phase, and decreased sleep and increased wake times during the rest phase. Additionally, the Btbd9 mutant mice had altered serum iron levels and monoamine neurotransmitter systems. Furthermore, the sensory alterations in the Btbd9 mutant mice were relieved using ropinirole, a dopaminergic agonist widely used for RLS treatment. These results, taken together, suggest that the Btbd9 mutant mice model several characteristics similar to RLS and would therefore be the first genotypic mouse model of RLS. Furthermore, our data provide further evidence that BTBD9 is involved in RLS, and future studies of the Btbd9 mutant mice will help shine light on its role in the pathophysiology of RLS. Finally, our data argue for the utility of Btbd9 mutant mice to discover and screen novel therapeutics for RLS.
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Affiliation(s)
- Mark P DeAndrade
- Interdisciplinary Program in Biomedical Sciences and Department of Neurology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
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In vivo mesolimbic D2/3 receptor binding predicts posttherapeutic clinical responses in restless legs syndrome: a positron emission tomography study. J Cereb Blood Flow Metab 2012; 32:654-62. [PMID: 22234337 PMCID: PMC3318153 DOI: 10.1038/jcbfm.2011.201] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Although D2/3 agonists have been used as a first-line medication for idiopathic restless legs syndrome (iRLS), findings on D2/3 receptors have been inconsistent. Here, we aimed to clarify the contribution of D2/3 receptor function to the clinical symptoms of iRLS by comparing the binding potential (BP(ND)) of [(11)C]raclopride with clinical improvements after D2/3 stimulation by pramipexole. Eight drug-naïve, iRLS patients and eight age-matched healthy subjects were scanned with positron emission tomography (PET). After PET scans, all patients received pramipexole (0.125 mg) orally for 2 weeks. Patients were evaluated every day with several standardized clinical tests. The BP(ND) values were compared using regions of interest and voxel-based methods. Results showed that the mean magnitude of [(11)C]raclopride BP(ND) in the mesolimbic dopamine region (nucleus accumbens (NA) and caudate) was significantly lower in the iRLS group. No significant differences between groups were observed in the putamen. The NA [(11)C]raclopride BP(ND) levels correlated negatively with clinical severity scores and positively with the degree of posttreatment improvement in iRLS. The present results suggest that alterations in mesolimbic D2/3 receptor function reflect the pathophysiology of iRLS, and the baseline availability of D2/3 receptors may predict the clinical outcome after D2/3 agonist treatment.
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Schmitz T, Endesfelder S, Reinert MC, Klinker F, Müller S, Bührer C, Liebetanz D. Adolescent hyperactivity and impaired coordination after neonatal hyperoxia. Exp Neurol 2012; 235:374-9. [PMID: 22449476 DOI: 10.1016/j.expneurol.2012.03.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 02/21/2012] [Accepted: 03/04/2012] [Indexed: 12/25/2022]
Abstract
In preterm infants, the risk to develop attention-deficit/hyperactivity disorder is 3 to 4-fold higher than in term infants. Moreover, preterm infants exhibit deficits in motor coordination and balance. Based on clinical data, higher oxygen levels in preterm infants lead to worse neurological outcome, and experimental hyperoxia causes wide-ranging cerebral changes in neonatal rodents. We hypothesize that hyperoxia in the immature brain may affect motor activity in preterm infants. We subjected newborn mice from P6 to P8 to 48 h of hyperoxia (80% O(2)) and tested motor activity in running wheels starting at adolescent age P30. Subsequently, from P44 to P53, regular wheels were replaced by complex wheels with variable crossbar positions to assess motor coordination deficits. MRI with diffusion tensor imaging was performed in the corpus callosum to determine white matter diffusivity in mice after hyperoxia at ages P30 and P53 in comparison to control animals. Adolescent mice after neonatal hyperoxia revealed significantly higher values for maximum velocity and mean velocity in regular wheels than controls (P<0.05). In the complex running wheels, however, maximum velocity was decreased in animals after hyperoxia, as compared to controls (P<0.05). Decreased fractional anisotropy and increased radial diffusion coefficient were observed in the corpus callosum of P30 and P53 mice after neonatal hyperoxia compared to control mice. Hyperoxia in the immature brain causes hyperactivity, motor coordination deficits, and impaired white matter diffusivity in adolescent and young adult mice.
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Affiliation(s)
- Thomas Schmitz
- Department of Neonatology, Charité University Medical Center, 13353 Berlin, Germany.
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Weller C, Zschüntzsch J, Makosch G, Metselaar JM, Klinker F, Klinge L, Liebetanz D, Schmidt J. Motor performance of young dystrophic mdx mice treated with long-circulating prednisolone liposomes. J Neurosci Res 2012; 90:1067-77. [PMID: 22253213 DOI: 10.1002/jnr.22825] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2011] [Revised: 10/19/2011] [Accepted: 10/21/2011] [Indexed: 01/12/2023]
Abstract
For Duchenne muscular dystrophy (DMD), a common myopathy that leads to severe disability, no causal therapy is available. Glucocorticosteroids improve patients' muscle strength, but their long-term use is limited by negative side effects. Thus, pharmacological modifications of glucocorticosteroids are required to increase the efficacy by drug targeting. Liposomal encapsulation augments systemic half-life and local tissue concentrations of glucocorticosteroids and, at the same time, reduces systemic side effects. In this study, the efficacy of novel, long-circulating, polyethylene-glycol-coated liposomes encapsulating prednisolone was compared with free prednisolone in the treatment of mdx mice, a well-established animal model for DMD. Using an objective and sensitive computerized 24-hr detection system of voluntary wheel-running in single cages, we demonstrate a significant impairment of the running performance in mdx compared with black/10 control mice aged 3-6 weeks. Treatment with liposomal or free prednisolone did not improve running performance compared with saline control or empty liposomes. Histopathological parameters, including the rate of internalized nuclei and fiber size variation, and mRNA and protein expression levels of transforming growth factor (TGF)-β and monocytes chemotactic protein (MCP)-1 also remained unchanged. Bioactivity in skeletal muscle of liposomal and free prednisolone was demonstrated by elevated mRNA expression of muscle ring finger protein 1 (MuRF1), a mediator of muscle atrophy, and its forkhead box transcription factors (Foxo1/3). Our data support the assessment of voluntary running to be a robust and reproducible outcome measure of skeletal muscle performance during the early disease course of mdx mice and suggest that liposomal encapsulation is not superior in treatment efficacy compared with conventional prednisolone. Our study helps to improve the future design of experimental treatment in animal models of neuromuscular diseases.
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Affiliation(s)
- Charlotte Weller
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
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Abstract
The effects of sleep deprivation on dopaminergic systems remain elusive, in part due to the lack of selective ligands for dopamine receptor subtypes. We examined D1, D2, and D3 receptor density in the mouse brain after sleep deprivation by receptor autoradiography using [H]SCH 23390 for D1R, [H]raclopride for D2R, and [H]WC-10 for D3R (a novel D3R-selective compound developed in our laboratory, not previously reported in mouse). Sleep-deprived mice showed a significant decrease in D1R, no change in D2R, and a significant increase in D3R binding in striatum. This pattern of dopamine receptor changes was not seen in mice subjected to restraint stress, suggesting specificity to sleep. These data provide evidence that brain dopaminergic circuits are remodeled after sleep deprivation.
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Tonic and phasic descending dopaminergic controls of nociceptive transmission in the medullary dorsal horn. Pain 2011; 152:1821-1831. [DOI: 10.1016/j.pain.2011.03.030] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 03/23/2011] [Accepted: 03/24/2011] [Indexed: 12/27/2022]
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Kosmidis S, Botella JA, Mandilaras K, Schneuwly S, Skoulakis EMC, Rouault TA, Missirlis F. Ferritin overexpression in Drosophila glia leads to iron deposition in the optic lobes and late-onset behavioral defects. Neurobiol Dis 2011; 43:213-9. [PMID: 21440626 DOI: 10.1016/j.nbd.2011.03.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Revised: 03/05/2011] [Accepted: 03/16/2011] [Indexed: 01/09/2023] Open
Abstract
Cellular and organismal iron storage depends on the function of the ferritin protein complex in insects and mammals alike. In the central nervous system of insects, the distribution and relevance of ferritin remain unclear, though ferritin has been implicated in Drosophila models of Alzheimers' and Parkinsons' disease and in Aluminum-induced neurodegeneration. Here we show that transgene-derived expression of ferritin subunits in glial cells of Drosophila melanogaster causes a late-onset behavioral decline, characterized by loss of circadian rhythms in constant darkness and impairment of elicited locomotor responses. Anatomical analysis of the affected brains revealed crystalline inclusions of iron-loaded ferritin in a subpopulation of glial cells but not significant neurodegeneration. Although transgene-induced glial ferritin expression was well tolerated throughout development and in young flies, it turned disadvantageous at older age. The flies we characterize in this report contribute to the study of ferritin in the Drosophila brain and can be used to assess the contribution of glial iron metabolism in neurodegenerative models of disease.
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Affiliation(s)
- Stylianos Kosmidis
- Institute of Cellular and Developmental Biology, BSRC Alexander Fleming, Vari 16672, Greece
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Klinker F, Hasan K, Dowling P, Paulus W, Liebetanz D. Dopamine D(3) receptor deficiency sensitizes mice to iron deficiency-related deficits in motor learning. Behav Brain Res 2011; 220:358-61. [PMID: 21354213 DOI: 10.1016/j.bbr.2011.02.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 01/21/2011] [Accepted: 02/16/2011] [Indexed: 12/26/2022]
Abstract
Iron deficiency is a widespread form of malnutrition and is known to interfere with cognitive performance and development. To elucidate the role of dopamine D3 and iron deficiency (ID) in inducing cognitive deficits, we studied wildtype and D3 knockout mice on normal or iron-deficient diets subjected to a running wheel-based motor skill sequence. Surprisingly, ID alone had no effect on motor learning in this study, whereas combined ID and dopamine D(3) receptor (D3R)-deficiency significantly interfered with the acquisition of motor skills. Reduced D3R function may serve as a predisposing factor towards ID-related effects on motor learning.
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Affiliation(s)
- F Klinker
- Department of Clinical Neurophysiology, University Medical Centre Göttingen, Georg August University, Robert-Koch-Strasse 40, Göttingen, Germany.
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Thorpe AJ, Clair A, Hochman S, Clemens S. Possible Sites of Therapeutic Action in Restless Legs Syndrome: Focus on Dopamine and α 2δ Ligands. Eur Neurol 2011; 66:18-29. [DOI: 10.1159/000328431] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Accepted: 04/11/2011] [Indexed: 01/01/2023]
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