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Xue Y, Xie S, Wang X, Xi X, Liu C. White matter microstructure alterations in idiopathic restless legs syndrome: a study combining crossing fiber-based and tensor-based approaches. Front Neurosci 2023; 17:1240929. [PMID: 37811323 PMCID: PMC10551141 DOI: 10.3389/fnins.2023.1240929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 09/07/2023] [Indexed: 10/10/2023] Open
Abstract
Introduction Restless legs syndrome (RLS) is a common sensorimotor disorder characterized by an irrepressible urge to move the legs and frequently accompanied by unpleasant sensations in the legs. The pathophysiological mechanisms underlying RLS remain unclear, and RLS is hypothesized to be associated with alterations in white matter tracts. Methods Diffusion MRI is a unique noninvasive method widely used to study white matter tracts in the human brain. Thus, diffusion-weighted images were acquired from 18 idiopathic RLS patients and 31 age- and sex-matched healthy controls (HCs). Whole brain tract-based spatial statistics (TBSS) and atlas-based analyzes combining crossing fiber-based metrics and tensor-based metrics were performed to investigate the white matter patterns in individuals with RLS. Results TBSS analysis revealed significantly higher fractional anisotropy (FA) and partial volume fraction of primary (F1) fiber populations in multiple tracts associated with the sensorimotor network in patients with RLS than in HCs. In the atlas based analysis, the bilateral anterior thalamus radiation, bilateral corticospinal tract, bilateral inferior fronto-occipital fasciculus, left hippocampal cingulum, left inferior longitudinal fasciculus, and left uncinate fasciculus showed significantl increased F1, but only the left hippocampal cingulum showed significantly higher FA. Discussion The results demonstrated that F1 identified extensive alterations in white matter tracts compared with FA and confirmed the hypothesis that crossing fiber-based metrics are more sensitive than tensor-based metrics in detecting white matter abnormalities in RLS. The present findings provide evidence that the increased F1 metric observed in sensorimotor tracts may be a critical neural substrate of RLS, enhancing our understanding of the underlying pathological changes.
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Affiliation(s)
- Yibo Xue
- School of Automation, Hangzhou Dianzi University, Hangzhou, China
| | - Sangma Xie
- School of Automation, Hangzhou Dianzi University, Hangzhou, China
| | - Xunheng Wang
- School of Automation, Hangzhou Dianzi University, Hangzhou, China
| | - Xugang Xi
- School of Automation, Hangzhou Dianzi University, Hangzhou, China
| | - Chunyan Liu
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
- Beijing Key Laboratory of Neuromodulation, Beijing, China
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Park KM, Kim KT, Lee DA, Cho YW. Structural brain connectivity in patients with restless legs syndrome: a diffusion tensor imaging study. Sleep 2022; 45:6575835. [PMID: 35485481 DOI: 10.1093/sleep/zsac099] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 04/07/2022] [Indexed: 11/13/2022] Open
Abstract
STUDY OBJECTIVES To evaluate alterations of global and local structural brain connectivity in patients with restless legs syndrome (RLS). METHODS Patients with primary RLS and healthy controls were recruited at a sleep center where they underwent diffusion tensor imaging (DTI) of the brain. We calculated the network measures of global and local structural brain connectivity based on the DTI in both groups using DSI studio program and a graph theory. RESULTS A total of 69 patients with primary RLS and 51 healthy controls were included in the study. We found a significant difference in the global structural connectivity between the groups. The transitivity in the patients with RLS was lower than that in healthy controls (0.031 vs. 0.033, p = 0.035). Additionally, there were significant differences in the local structural connectivity between the groups. The characteristic path length (r = 0.283, p = 0.018), radius of graph (r = 0.260, p = 0.030), and diameter of graph (r = 0.280, p = 0.019) were all positively correlated with RLS severity, whereas the mean clustering coefficient (r = -0.327, p = 0.006), global efficiency (r = -0.272, p = 0.023), small-worldness index (r = -0.325, p = 0.006), and transitivity (r = -0.351, p = 0.003) were negatively correlated with RLS severity. CONCLUSION We identified changes in the global structural connectivity of patients with RLS using graph theory based on DTI, which showed decreased segregation in the brain network compared to healthy controls. These changes are well correlated with RLS severity. We also found changes in local structural connectivity, especially in regions involved in sensorimotor function, which suggests that these areas play a pivotal role in RLS. These findings contribute to a better understanding of the pathophysiology of RLS symptoms.
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Affiliation(s)
- Kang Min Park
- Department of Neurology, Haeundae Paik Hospital, Inje University College of Medicine, Busan, South Korea
| | - Keun Tae Kim
- Department of Neurology, Keimyung University School of Medicine, Daegu, South Korea
| | - Dong Ah Lee
- Department of Neurology, Haeundae Paik Hospital, Inje University College of Medicine, Busan, South Korea
| | - Yong Won Cho
- Department of Neurology, Keimyung University School of Medicine, Daegu, South Korea
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Garcia-Malo C, Novo-Ponte S, Castro-Villacañas Farzamnia A, Boi S, Miranda Castillo C, Romero Peralta S, Martínez Vidal V, Botta L, Anguizola S, Cano-Pumarega I, Garcia-Borreguero D. Correlation between systemic iron parameters and substantia nigra iron stores in restless legs syndrome. Sleep Med 2021; 85:191-195. [PMID: 34343769 DOI: 10.1016/j.sleep.2021.07.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 06/18/2021] [Accepted: 07/13/2021] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To evaluate the relation between systemic iron parameters (SIP) and substantia nigra (SN) iron deposits, as assessed by transcranial sonography (TCS) in restless legs syndrome (RLS). METHODS We conducted a cross-sectional study in RLS patients, from whom blood samples with SIP were obtained, consisting of total iron-binding capacity (TIBC), serum ferritin, hemoglobin, transferrin saturation (TSAT), serum iron, and serum transferrin. TCS was performed over the SN, and the substantia nigra echogenicity index (SNEI) was determined according to established methods. Symptom severity was evaluated using the international restless legs scale (IRLS). A Spearman correlation was performed. RESULTS A total of 167 patients were studied. Correlations between SNEI and SIP were as follows: serum ferritin (R = 0.0422; n.s.), TSAT (R = 0.0883; n.s.), TIBC (R = -0.1091; n.s.), serum transferrin (R = -0.0420; n.s.), hemoglobin (R = 0.0185; n.s.), serum iron (R = 0.0389; n.s.). No correlation was found with age and IRLS (R = 0.1375; n.s. and R = 0.0880, n.s., respectively). CONCLUSIONS SIP are not correlated with SN iron content in RLS, quantified by means of TCS. TCS of the SN might be a more valid estimate and could be useful in the evaluation of RLS patients.
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Affiliation(s)
- Celia Garcia-Malo
- Sleep Research Institute, Madrid, Spain; PhD Program in Neuroscience, Autonoma de Madrid University, Madrid, 28029, Spain.
| | - Sabela Novo-Ponte
- Sleep Research Institute, Madrid, Spain; Neurology Department, Hospital Universitario Puerta de Hierro, Majadahonda, Madrid, Spain
| | | | - Sara Boi
- Sleep Research Institute, Madrid, Spain
| | - Carolina Miranda Castillo
- Sleep Research Institute, Madrid, Spain; Hematology Department, Hospital Rey Juan Carlos, Móstoles, Spain
| | - Sofia Romero Peralta
- Sleep Research Institute, Madrid, Spain; Sleep Unit. Respiratory Department, Hospital Universitario de Guadalajara, Guadalajara, Spain
| | | | | | | | - Irene Cano-Pumarega
- Sleep Research Institute, Madrid, Spain; Sleep Unit. Respiratory Department, Hospital Ramón y Cajal (IRYCIS), Madrid, Spain
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Garcia-Malo C, Romero-Peralta S, Cano-Pumarega I. Restless Legs Syndrome - Clinical Features. Sleep Med Clin 2021; 16:233-247. [PMID: 33985650 DOI: 10.1016/j.jsmc.2021.02.002] [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: 10/21/2022]
Abstract
Restless legs syndrome (RLS) is one of the most common neurologic conditions, with an estimated prevalence in European and North American heritage populations of about 2% to 5%. Because RLS diagnosis is essentially clinical, a careful evaluation of the symptoms is mandatory. It is important to exclude RLS mimics and evaluate factors that could exacerbate RLS symptoms. It is mandatory to evaluate systemic iron parameters, because the initial treatment depends on this result. Other complementary tests could help support the diagnosis or exclude mimics. The decision about when and how to treat should be carefully tailored to each patient.
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Affiliation(s)
- Celia Garcia-Malo
- Sleep Research Institute, Calle del Padre Damián, 44, Madrid 28036, Spain.
| | - Sofia Romero-Peralta
- Sleep Research Institute, Calle del Padre Damián, 44, Madrid 28036, Spain; Sleep Unit, Respiratory Department, Hospital de Guadalajara, Guadalajara, Spain
| | - Irene Cano-Pumarega
- Sleep Research Institute, Calle del Padre Damián, 44, Madrid 28036, Spain; Sleep Unit, Respiratory Department, Hospital Ramón y Cajal, IRYCIS, CIBERES, Madrid, Spain
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Colzato LS, Zhang W, Brandt MD, Stock AK, Beste C. Cognitive profile in Restless Legs Syndrome: A signal-to-noise ratio account. CURRENT RESEARCH IN NEUROBIOLOGY 2021; 2:100021. [PMID: 36246509 PMCID: PMC9559071 DOI: 10.1016/j.crneur.2021.100021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 07/05/2021] [Accepted: 07/29/2021] [Indexed: 11/19/2022] Open
Abstract
Restless legs syndrome (RLS) is a common neurological disorder characterized by a sensorimotor condition, where patients feel an uncontrollable urge to move the lower limbs in the evening and/or during the night. RLS does not only have a profound impact on quality of life due to the disturbed night-time sleep, but there is growing evidence that untreated or insufficiently managed RLS might also cause cognitive changes in patients affected by this syndrome. It has been proposed that RLS is caused by alterations in the signal-to-noise ratio (SNR) and in dopamine (DA) neurotransmission in the nervous system. Based on this evidence, we propose the “SNR-DA hypothesis” as an explanation of how RLS could affect cognitive performance. According to this hypothesis, variations/reductions in the SNR underlie RLS-associated cognitive deficits, which follow an inverted U-shaped function: In unmedicated patients, low dopamine levels worsen the SNR, which eventually impairs cognition. Pharmacological treatment enhances DA levels in medicated patients, which likely improves/normalizes the SNR in case of optimal doses, thus restoring cognition to a normal level. However, overmedication might push patients past the optimal point on the inverted U-shaped curve, where an exaggerated SNR potentially impairs cognitive performance relying on cortical noise such as cognitive flexibility. Based on these assumptions of SNR alterations, we propose to directly measure neural noise via “1/f noise” and related metrics to use transcranial random noise stimulation (tRNS), a noninvasive brain stimulation method which manipulates the SNR, as a research tool and potential treatment option for RLS. Restless legs syndrome (RLS) is a common neurological disorder. RLS is caused by alterations in the SNR ratio and in DA neurotransmission. The SNR- DA hypothesis how RLS affects cognitive performance is presented.
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Affiliation(s)
- Lorenza S. Colzato
- Cognitive Neurophysiology, Department of Child and Adolescent Psychiatry, Faculty of Medicine, TU Dresden, Germany
- Cognitive Psychology, Faculty of Psychology, Shandong Normal University, Jinan, China
- University Neuropsychology Center, Faculty of Medicine, TU Dresden, Germany
| | - Wenxin Zhang
- Cognitive Psychology, Faculty of Psychology, Shandong Normal University, Jinan, China
| | - Moritz D. Brandt
- Department of Neurology, University Hospital, Technische Universität Dresden, Dresden, Germany
- German Center for Neurodegenerative Diseases (DZNE) Dresden, Dresden, Germany
| | - Ann-Kathrin Stock
- Cognitive Neurophysiology, Department of Child and Adolescent Psychiatry, Faculty of Medicine, TU Dresden, Germany
- University Neuropsychology Center, Faculty of Medicine, TU Dresden, Germany
- Biopsychology, Faculty of Psychology, TU Dresden, Dresden, Germany
| | - Christian Beste
- Cognitive Neurophysiology, Department of Child and Adolescent Psychiatry, Faculty of Medicine, TU Dresden, Germany
- Cognitive Psychology, Faculty of Psychology, Shandong Normal University, Jinan, China
- University Neuropsychology Center, Faculty of Medicine, TU Dresden, Germany
- Corresponding author. Cognitive Neurophysiology, Department of Child and Adolescent Psychiatry, Faculty of Medicine of the TU Dresden, Germany Schubertstrasse 42, D-01309, Dresden, Germany.
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Abstract
Restless legs syndrome (RLS), with a lifetime prevalence of up to 10%, is a frequent neurological disease and the most common movement disorder in sleep. A compulsive urge to move the legs with sensory symptoms and sleep disturbances can significantly impair the quality of life. Furthermore, RLS frequently occurs as a comorbidity to various internal and neurological diseases. It is diagnosed clinically based on the five essential diagnostic criteria. For treatment, an iron deficiency should first be excluded. Drugs approved for the treatment of RLS include dopaminergics (L-DOPA/benserazide) and dopamine agonists as well as oxycodone/naloxone, as a second-line treatment in severe cases. Augmentation as a deterioration of symptoms is a clinically defined complication of high-dose dopaminergic treatment, requiring special management strategies. Due to its high prevalence of up to 25%, RLS plays also an important role in the care of pregnant women.
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Restless-legs-Syndrom: ein Update. SOMNOLOGIE 2020. [DOI: 10.1007/s11818-020-00283-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Garcia-Malo C, Peralta SR, Garcia-Borreguero D. Restless Legs Syndrome and Other Common Sleep-Related Movement Disorders. Continuum (Minneap Minn) 2020; 26:963-987. [PMID: 32756231 DOI: 10.1212/con.0000000000000886] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
PURPOSE OF REVIEW In this article, the different sleep-related movement disorders are discussed with special attention given to restless legs syndrome (RLS). RECENT FINDINGS The differential diagnosis of sleep-related movement disorders can often be challenging; therefore, it is essential to have accurate information to make a correct diagnosis. This article focuses on RLS, highlighting the change in the paradigm of initial treatment, the role played by iron (pathophysiologic and therapeutic), and how to approach possible complications occurring with long-term treatment. SUMMARY RLS is one of the most common neurologic conditions, and it is common in clinical practice to find patients experiencing symptoms suggestive of RLS. Neurologists must be careful and thorough in the diagnosis, excluding RLS mimics. The decisions regarding which specific sleep-related movement disorder is present and how it should be treated are important because in certain cases, especially in RLS, adverse effects and long-term complications are frequently reported with the use of certain drugs.
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Low risk of iron overload or anaphylaxis during treatment of restless legs syndrome with intravenous iron: a consecutive case series in a regular clinical setting. Sleep Med 2020; 74:48-55. [PMID: 32841843 DOI: 10.1016/j.sleep.2020.06.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 05/21/2020] [Accepted: 06/01/2020] [Indexed: 12/24/2022]
Abstract
OBJECTIVE To evaluate the incidence of iron overload and anaphylaxis following intravenous (IV) iron treatment of restless legs syndrome (RLS). METHODS A total of 58 consecutive RLS patients, meeting clinical requirements for IV iron treatment according to current IRLSSG guidelines were recruited. IV iron treatment consisted of two 500 mg infusions of ferric carboxymaltose (FCM) administered five days apart. During each of the three follow-up visits we obtained blood samples, substantia nigra echogenity index (SNEI) by means of transcranial sonography (TCS), and assessed the severity of RLS symptoms (IRLS scale). "Iron overload risk" was defined as transferrin saturation (TSAT) > 45% on two consecutive follow-up visits. In patients who had a reduction in systemic iron levels following treatment, an additional 500 mg of FCM was administered when feasible. In such cases an additional two follow-up visits were performed. RESULTS Among the total sample, only 2/58 participants met criteria for iron overload risk. They had no evidence of liver damage and did not require additional treatment. Among the 21 patients receiving an additional 500 mg infusion after, only one patient was diagnosed with iron overload risk. Among these three patients, only one was a hemochromatosis gene carrier. No anaphylaxis or other side-effects were reported. CONCLUSIONS In real-life clinical conditions, the risk of iron overload is low when IV FCM is administered according to the safety limits defined in the current RLS treatment guidelines. However, a close clinical follow-up with periodic blood sampling for iron status, is needed.
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Thalamic GABA may modulate cognitive control in restless legs syndrome. Neurosci Lett 2019; 712:134494. [DOI: 10.1016/j.neulet.2019.134494] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 09/03/2019] [Accepted: 09/10/2019] [Indexed: 11/18/2022]
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Garcia-Malo C, Wanner V, Miranda C, Romero Peralta S, Agudelo L, Cano-Pumarega I, Granizo JJ, Garcia-Borreguero D. Quantitative transcranial sonography of the substantia nigra as a predictor of therapeutic response to intravenous iron therapy in restless legs syndrome. Sleep Med 2019; 66:123-129. [PMID: 31875533 DOI: 10.1016/j.sleep.2019.09.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 09/09/2019] [Accepted: 09/16/2019] [Indexed: 12/30/2022]
Abstract
OBJECTIVE To analyze changes in substantia nigra (SN) iron deposits, assessed by quantitative transcranial sonography (TCS), to obtain and compare substantia nigra echogenicity indices (SNEI) at baseline and after intravenous (IV) iron therapy in patients with restless legs syndrome (RLS)/Willis-Ekbom disease (WED). METHODS A total of 30 consecutive subjects diagnosed with RLS/WED were recruited and underwent IV iron treatment. The SNEI, total daily dose of dopamine equivalents, and International Restless Legs Syndrome Rating Scale (IRLS) scores were obtained at baseline and following IV iron administration. Comparative statistics were performed by means of nonparametric testing. RESULTS The sample was stratified into two groups according to the median baseline SNEI and the grade of SN hypoechogenicity: severely hypoechogenic (HE) (n = 13) and moderately HE (n = 17). Following IV iron, the increase in SNEI among severely HE subjects was 19% (0.038 ± 0.046 cm2; P < 0.01), whereas in moderately HE subjects it was 10% (0.021 ± 0.069 cm2; P = 0.28). Among severely HE subjects, the average reduction in IRLS following IV iron was 10 ± 7.12 points (P < 0.01), in contrast to 1.85 ± 9.85 (not significant) among moderately HE subjects. Finally, we quantified the percentage of patients in each group who were able to reduce by ≥30% their total daily dopaminergic requirements (TDR) after IV iron, with a 57.14% reduction in the severely HE group vs 25% in the moderately HE group (P = 0.1). Three of 30 subjects (17%) were able to completely cease all dopaminergic treatment. CONCLUSION Intravenous iron caused changes in SNEI in both groups of patients, reflecting an increase in brain iron stores. However, the increase in SNEI was greater in patients previously defined as severely HE. Furthermore, RLS/WED symptoms also improved more in severely HE subjects, and there was a greater reduction in TDR. This study highlights the role of TCS in quantifying brain iron deposits and in predicting which patients will likely benefit from IV iron.
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Affiliation(s)
| | | | | | | | | | - Irene Cano-Pumarega
- Sleep Research Institute, Madrid, Spain; Sleep Unit, Respiratory Department, Hospital Ramón y Cajal (IRYCIS), Madrid, Spain
| | - Juan José Granizo
- Unidad de Apoyo a la Investigación, Hospital Universitario Infanta Cristina, Parla, Spain; Instituto de Investigación Sanitaria Puerta de Hierro-Segovia de Arana, Majadahonda, Spain
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Chiaro G, Manconi M. Restless legs syndrome, periodic limb movements during sleep and cardiovascular risk. Auton Neurosci 2019; 220:102554. [PMID: 31331694 DOI: 10.1016/j.autneu.2019.102554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 05/20/2019] [Accepted: 05/28/2019] [Indexed: 12/16/2022]
Abstract
Multiple mechanisms may modulate an association between restless legs syndrome/Willis-Ekbom disease (RLS/WED) and cardiovascular disease (CVD), including chronic sleep deprivation, intermittent, periodic limb movements in sleep (PLMS)-related autonomic fluctuations and possible autonomic dysfunction intrinsically associated with RLS per se. The purpose of this paper is to review the existing RLS/WED literature focusing on the pathophysiologic evidence for possible associations between RLS/WED and PLMS with CVD and events (CVE). Specific intrinsic dysautonomic aspects of the disease, which may contribute to generating CVD, are separately discussed. The association between RLS/WED and both CV risk factors and CVD still remains elusive. Although several shared pathophysiological causes could explain these possible relationships, the emerging body of literature focusing on these disorders remains controversial. Not only longitudinal population-based studies and meta-analyses, but also more animal models and therapeutic interventions are needed in order to build a sufficiently robust body of evidence on this topic.
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Affiliation(s)
- Giacomo Chiaro
- Sleep and Epilepsy Center, Neurocenter of Southern Switzerland, Civic Hospital of Lugano, Lugano, Switzerland; Department of Biomedical and Neuromotor Sciences, Bellaria Hospital, University of Bologna, Bologna, Italy
| | - Mauro Manconi
- Sleep and Epilepsy Center, Neurocenter of Southern Switzerland, Civic Hospital of Lugano, Lugano, Switzerland; Department of Neurology, Bern University Hospital, Bern, Switzerland.
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Affiliation(s)
- Tadaaki Mano
- From the Gifu University of Medical Science (T.M.), Seki, Gifu, Japan; and Division of Pulmonary, Critical Care & Sleep (R.J.T.), Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
| | - Robert J Thomas
- From the Gifu University of Medical Science (T.M.), Seki, Gifu, Japan; and Division of Pulmonary, Critical Care & Sleep (R.J.T.), Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
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A Restless Leg Syndrome Incidentally Detected by an 18F-FDG Positron Emission Tomography. Clin Nucl Med 2017; 42:389-390. [DOI: 10.1097/rlu.0000000000001583] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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16
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Patton SM, Wang Q, Hulgan T, Connor JR, Jia P, Zhao Z, Letendre SL, Ellis RJ, Bush WS, Samuels DC, Franklin DR, Kaur H, Iudicello J, Grant I, Kallianpur AR. Cerebrospinal fluid (CSF) biomarkers of iron status are associated with CSF viral load, antiretroviral therapy, and demographic factors in HIV-infected adults. Fluids Barriers CNS 2017; 14:11. [PMID: 28427421 PMCID: PMC5399327 DOI: 10.1186/s12987-017-0058-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 04/01/2017] [Indexed: 02/06/2023] Open
Abstract
Background HIV-associated neurocognitive disorder (HAND) remains common, despite antiretroviral therapy (ART). HIV dysregulates iron metabolism, but cerebrospinal fluid (CSF) levels of iron and iron-transport proteins in HIV-infected (HIV+) persons are largely unknown. The objectives of this study were to characterize CSF iron-related biomarkers in HIV+ adults and explore their relationships to known predictors of HAND. Methods We quantified total iron, transferrin and heavy-chain (H)-ferritin by immunoassay in CSF sampled by lumbar puncture in 403 HIV+ participants in a multi-center, observational study and evaluated biomarker associations with demographic and HIV-related correlates of HAND [e.g., age, sex, self-reported race/ethnicity, ART, and detectable plasma virus and CSF viral load (VL)] by multivariable regression. In a subset (N = 110) with existing CSF: serum albumin (QAlb) measurements, QAlb and comorbidity severity were also included as covariates to account for variability in the blood–CSF-barrier. Results Among 403 individuals (median age 43 years, 19% women, 56% non-Whites, median nadir CD4+ T cell count 180 cells/µL, 46% with undetectable plasma virus), men had 25% higher CSF transferrin (median 18.1 vs. 14.5 µg/mL), and 71% higher H-ferritin (median 2.9 vs. 1.7 ng/mL) than women (both p-values ≤0.01). CSF iron was 41% higher in self-reported Hispanics and 27% higher in (non-Hispanic) Whites than in (non-Hispanic) Blacks (median 5.2 and 4.7 µg/dL in Hispanics and Whites, respectively, vs. 3.7 µg/dL in Blacks, both p ≤ 0.01); these findings persisted after adjustment for age, sex, and HIV-specific factors. Median H-ferritin was 25% higher (p < 0.05), and transferrin 14% higher (p = 0.06), in Whites than Blacks. Transferrin and H-ferritin were 33 and 50% higher, respectively, in older (age > 50 years) than in younger persons (age ≤ 35 years; both p < 0.01), but these findings lost statistical significance in subset analyses that adjusted for QAlb and comorbidity. After these additional adjustments, associations were observed for CSF iron and transferrin with race/ethnicity as well as CSF VL, for transferrin with sex and ART, and for H-ferritin with plasma virus detectability and significant comorbidity (all p < 0.05). Conclusions CSF iron biomarkers are associated with demographic factors, ART, and CSF VL in HIV+ adults. Future studies should investigate a role for CNS iron dysregulation, to which an altered blood-CSF barrier may contribute, in HAND. Electronic supplementary material The online version of this article (doi:10.1186/s12987-017-0058-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Stephanie M Patton
- Department of Neurosurgery, Penn State Hershey Medical Center, 500 University Drive, Mailbox H110, Hershey, PA, 17033, USA.
| | - Quan Wang
- Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Todd Hulgan
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - James R Connor
- Department of Neurosurgery, Penn State Hershey Medical Center, 500 University Drive, Mailbox H110, Hershey, PA, 17033, USA
| | - Peilin Jia
- School of Biomedical Informatics, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Zhongming Zhao
- School of Biomedical Informatics, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Scott L Letendre
- Department of Medicine, University of California-San Diego, San Diego, CA, USA
| | - Ronald J Ellis
- Department of Neurology, University of California-San Diego, San Diego, CA, USA
| | - William S Bush
- Department of Epidemiology and Biostatistics, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - David C Samuels
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Donald R Franklin
- Department of Medicine, University of California-San Diego, San Diego, CA, USA
| | - Harpreet Kaur
- Genomic Medicine Institute, Cleveland Clinic/Lerner Research Institute, Cleveland, OH, USA
| | - Jennifer Iudicello
- Department of Psychiatry, University of California-San Diego, San Diego, CA, USA
| | - Igor Grant
- Department of Psychiatry, University of California-San Diego, San Diego, CA, USA
| | - Asha R Kallianpur
- Genomic Medicine Institute, Cleveland Clinic/Lerner Research Institute, Cleveland, OH, USA.,Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA
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Stroh MA, Winter MK, Swerdlow RH, McCarson KE, Zhu H. Loss of NCB5OR in the cerebellum disturbs iron pathways, potentiates behavioral abnormalities, and exacerbates harmaline-induced tremor in mice. Metab Brain Dis 2016; 31:951-64. [PMID: 27188291 PMCID: PMC5929129 DOI: 10.1007/s11011-016-9834-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 05/01/2016] [Indexed: 12/13/2022]
Abstract
Iron dyshomeostasis has been implicated in many diseases, including a number of neurological conditions. Cytosolic NADH cytochrome b5 oxidoreductase (NCB5OR) is ubiquitously expressed in animal tissues and is capable of reducing ferric iron in vitro. We previously reported that global gene ablation of NCB5OR resulted in early-onset diabetes and altered iron homeostasis in mice. To further investigate the specific effects of NCB5OR deficiency on neural tissue without contributions from known phenotypes, we generated a conditional knockout (CKO) mouse that lacks NCB5OR only in the cerebellum and midbrain. Assessment of molecular markers in the cerebellum of CKO mice revealed changes in pathways associated with cellular and mitochondrial iron homeostasis. (59)Fe pulse-feeding experiments revealed cerebellum-specific increased or decreased uptake of iron by 7 and 16 weeks of age, respectively. Additionally, we characterized behavioral changes associated with loss of NCB5OR in the cerebellum and midbrain in the context of dietary iron deprivation-evoked generalized iron deficiency. Locomotor activity was reduced and complex motor task execution was altered in CKO mice treated with an iron deficient diet. A sucrose preference test revealed that the reward response was intact in CKO mice, but that iron deficient diet consumption altered sucrose preference in all mice. Detailed gait analysis revealed locomotor changes in CKO mice associated with dysfunctional proprioception and locomotor activation independent of dietary iron deficiency. Finally, we demonstrate that loss of NCB5OR in the cerebellum and midbrain exacerbated harmaline-induced tremor activity. Our findings suggest an essential role for NCB5OR in maintaining both iron homeostasis and the proper functioning of various locomotor pathways in the mouse cerebellum and midbrain.
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Affiliation(s)
- Matthew A Stroh
- Landon Center on Aging, University of Kansas Medical Center, 3901 Rainbow Blvd., MSN 1005, Kansas City, KS, 66160, USA
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, 3901 Rainbow Blvd., MSN 3030, Kansas City, KS, 66160, USA
- Neuroscience Graduate Program, University of Kansas Medical Center, 3901 Rainbow Blvd., MSN 3038, Kansas City, KS, 66160, USA
| | - Michelle K Winter
- Kansas Intellectual and Developmental Disabilities Research Center, University of Kansas Medical Center, 3901 Rainbow Blvd., MSN 3051, Kansas City, KS, 66160, USA
| | - Russell H Swerdlow
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, 3901 Rainbow Blvd., MSN 3030, Kansas City, KS, 66160, USA
- Neuroscience Graduate Program, University of Kansas Medical Center, 3901 Rainbow Blvd., MSN 3038, Kansas City, KS, 66160, USA
- Department of Neurology, University of Kansas Medical Center, 3599 Rainbow Blvd., MSN 2012, Kansas City, KS, 66160, USA
| | - Kenneth E McCarson
- Kansas Intellectual and Developmental Disabilities Research Center, University of Kansas Medical Center, 3901 Rainbow Blvd., MSN 3051, Kansas City, KS, 66160, USA
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, 3901 Rainbow Blvd., MSN 1018, Kansas City, KS, 66160, USA
| | - Hao Zhu
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, 3901 Rainbow Blvd., MSN 3030, Kansas City, KS, 66160, USA.
- Neuroscience Graduate Program, University of Kansas Medical Center, 3901 Rainbow Blvd., MSN 3038, Kansas City, KS, 66160, USA.
- Department of Clinical Laboratory Sciences, University of Kansas Medical Center, 3901 Rainbow Blvd., MSN 4048G-Eaton, Kansas City, KS, 66160, USA.
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