1
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Bromley LE, Weinstock-Guttman B. Effects of Physical Therapy and Dalfampridine on Function and Quality of Life in Nonambulatory Individuals With Multiple Sclerosis: A Randomized Controlled Trial. Int J MS Care 2024; 26:98-103. [PMID: 38765304 PMCID: PMC11096856 DOI: 10.7224/1537-2073.2023-063] [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: 05/22/2024]
Abstract
BACKGROUND Decreases in mobility, quality of life (QOL) and cognition are commonly seen in people with multiple sclerosis (MS). Physical therapy (PT) and exercise have been shown to improve many symptoms in ambulatory individuals with MS; however, evidence in nonambulatory people with MS is lacking. Dalfampridine is a US Food and Drug Administration-approved medication for MS that treats impaired ambulation by enhancing nerve conduction. To our knowledge, no study has examined the combined effect of PT and dalfampridine and very few studies have examined dalfampridine's effect on function in individuals with more progressive disease. The purpose of this study was to examine the effectiveness of PT combined with dalfampridine or a placebo on function, QOL, and cognition in nonambulatory individuals with MS. In addition, we explored the benefits of PT in all participants to increase the extremely limited research in this population. METHODS Adults with MS were randomly assigned to receive dalfampridine (n = 13) or placebo (n = 14) for 12 weeks in conjunction with PT treatment 2 times a week. Function, QOL, and cognition were assessed at baseline, 6 weeks, and 12 weeks. RESULTS There was a significant time × group interaction for the Multiple Sclerosis Quality of Life-54 favoring the placebo group. Both groups significantly improved on the 9-Hole Peg Test (left arm only), sitting lateral reach (right), transferring from wheelchair to mat, and repeated sit to stand. CONCLUSIONS The addition of dalfampridine to physical therapy did not improve function, QOL, or cognitive processing speed. Importantly, this study demonstrated an overall benefit in function and QOL with physical therapy 2 times a week for 12 weeks for nonambulatory individuals with MS.
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Affiliation(s)
- Lacey E. Bromley
- From the Department of Physical Therapy, D’Youville University, Buffalo, NY, USA
| | - Bianca Weinstock-Guttman
- the Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
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2
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Morris PG, Taylor JD, Paton JFR, Nogaret A. Single shot detection of alterations across multiple ionic currents from assimilation of cell membrane dynamics. Sci Rep 2024; 14:6031. [PMID: 38472404 DOI: 10.1038/s41598-024-56576-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 03/08/2024] [Indexed: 03/14/2024] Open
Abstract
The dysfunction of ion channels is a causative factor in a variety of neurological diseases, thereby defining the implicated channels as key drug targets. The detection of functional changes in multiple specific ionic currents currently presents a challenge, particularly when the neurological causes are either a priori unknown, or are unexpected. Traditional patch clamp electrophysiology is a powerful tool in this regard but is low throughput. Here, we introduce a single-shot method for detecting alterations amongst a range of ion channel types from subtle changes in membrane voltage in response to a short chaotically driven current clamp protocol. We used data assimilation to estimate the parameters of individual ion channels and from these we reconstructed ionic currents which exhibit significantly lower error than the parameter estimates. Such reconstructed currents thereby become sensitive predictors of functional alterations in biological ion channels. The technique correctly predicted which ionic current was altered, and by approximately how much, following pharmacological blockade of BK, SK, A-type K+ and HCN channels in hippocampal CA1 neurons. We anticipate this assay technique could aid in the detection of functional changes in specific ionic currents during drug screening, as well as in research targeting ion channel dysfunction.
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Affiliation(s)
- Paul G Morris
- Department of Physics, University of Bath, Claverton Down, Bath, UK
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Joseph D Taylor
- Department of Physics, University of Bath, Claverton Down, Bath, UK
| | - Julian F R Paton
- Manaaki Manawa - the Centre for Heart Research, Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Grafton, Auckland, New Zealand
| | - Alain Nogaret
- Department of Physics, University of Bath, Claverton Down, Bath, UK.
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3
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Eguibar JR, Cortes C, Hernandez VH, Lopez-Juarez A, Piazza V, Carmona D, Kleinert-Altamirano A, Morales-Campos B, Salceda E, Roncagliolo M. 4-aminopyridine improves evoked potentials and ambulation in the taiep rat: A model of hypomyelination with atrophy of basal ganglia and cerebellum. PLoS One 2024; 19:e0298208. [PMID: 38427650 PMCID: PMC10906851 DOI: 10.1371/journal.pone.0298208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Accepted: 01/21/2024] [Indexed: 03/03/2024] Open
Abstract
The taiep rat is a tubulin mutant with an early hypomyelination followed by progressive demyelination of the central nervous system due to a point mutation in the Tubb4a gene. It shows clinical, radiological, and pathological signs like those of the human leukodystrophy hypomyelination with atrophy of the basal ganglia and cerebellum (H-ABC). Taiep rats had tremor, ataxia, immobility episodes, epilepsy, and paralysis; the acronym of these signs given the name to this autosomal recessive trait. The aim of this study was to analyze the characteristics of somatosensory evoked potentials (SSEPs) and motor evoked potentials (MEPs) in adult taiep rats and in a patient suffering from H-ABC. Additionally, we evaluated the effects of 4-aminopyridine (4-AP) on sensory responses and locomotion and finally, we compared myelin loss in the spinal cord of adult taiep and wild type (WT) rats using immunostaining. Our results showed delayed SSEPs in the upper and the absence of them in the lower extremities in a human patient. In taiep rats SSEPs had a delayed second negative evoked responses and were more susceptible to delayed responses with iterative stimulation with respect to WT. MEPs were produced by bipolar stimulation of the primary motor cortex generating a direct wave in WT rats followed by several indirect waves, but taiep rats had fused MEPs. Importantly, taiep SSEPs improved after systemic administration of 4-AP, a potassium channel blocker, and this drug induced an increase in the horizontal displacement measured in a novelty-induced locomotor test. In taiep subjects have a significant decrease in the immunostaining of myelin in the anterior and ventral funiculi of the lumbar spinal cord with respect to WT rats. In conclusion, evoked potentials are useful to evaluate myelin alterations in a leukodystrophy, which improved after systemic administration of 4-AP. Our results have a translational value because our findings have implications in future medical trials for H-ABC patients or with other leukodystrophies.
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Affiliation(s)
- Jose R. Eguibar
- Laboratorio de Neurofisiología de la Conducta y Control Motor, Instituto de Fisiología, Benemérita Universidad Autónoma de Puebla, Puebla, Pue, México
- Dirección General de Desarrollo Internacional, Benemérita Universidad Autónoma de Puebla, Puebla, Pue, México
| | - Carmen Cortes
- Laboratorio de Neurofisiología de la Conducta y Control Motor, Instituto de Fisiología, Benemérita Universidad Autónoma de Puebla, Puebla, Pue, México
| | - Victor H. Hernandez
- Departamento de Ingenierías Química, Electrónica y Biomédica, División de Ciencias e Ingenierías, Universidad de Guanajuato, León, Gto, México
| | - Alejandra Lopez-Juarez
- Departamento de Ingenierías Química, Electrónica y Biomédica, División de Ciencias e Ingenierías, Universidad de Guanajuato, León, Gto, México
| | - Valeria Piazza
- Centro de Investigaciones en Óptica, A.C., León, Gto, México
| | - Diego Carmona
- Departamento de Ingenierías Química, Electrónica y Biomédica, División de Ciencias e Ingenierías, Universidad de Guanajuato, León, Gto, México
- Centro de Investigaciones en Óptica, A.C., León, Gto, México
| | | | - Blanca Morales-Campos
- Departamento de Fisiología, Facultad de Medicina, Benemérita Universidad Autónoma de Puebla, Puebla, Puebla, Pue, México
| | - Emilio Salceda
- Revista Elementos, Benemérita Universidad Autónoma de Puebla, Puebla, Pue, México
| | - Manuel Roncagliolo
- Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
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4
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McClintic WT, Chandler ZD, Karchalla LM, Ondeck CA, O'Brien SW, Campbell CJ, Jacobson AR, McNutt PM. Aminopyridines Restore Ventilation and Reverse Respiratory Acidosis at Late Stages of Botulism in Mice. J Pharmacol Exp Ther 2024; 388:637-646. [PMID: 37977816 PMCID: PMC10801772 DOI: 10.1124/jpet.123.001773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 09/19/2023] [Accepted: 09/25/2023] [Indexed: 11/19/2023] Open
Abstract
Botulinum neurotoxin (BoNT) is a potent protein toxin that causes muscle paralysis and death by asphyxiation. Treatments for symptomatic botulism are intubation and supportive care until respiratory function recovers. Aminopyridines have recently emerged as potential treatments for botulism. The clinically approved drug 3,4-diaminopyridine (3,4-DAP) rapidly reverses toxic signs of botulism and has antidotal effects when continuously administered in rodent models of lethal botulism. Although the therapeutic effects of 3,4-DAP likely result from the reversal of diaphragm paralysis, the corresponding effects on respiratory physiology are not understood. Here, we combined unrestrained whole-body plethysmography (UWBP) with arterial blood gas measurements to study the effects of 3,4-DAP, and other aminopyridines, on ventilation and respiration at terminal stages of botulism in mice. Treatment with clinically relevant doses of 3,4-DAP restored ventilation in a dose-dependent manner, producing significant improvements in ventilatory parameters within 10 minutes. Concomitant with improved ventilation, 3,4-DAP treatment reversed botulism-induced respiratory acidosis, restoring blood levels of CO2, pH, and lactate to normal physiologic levels. Having established that 3,4-DAP-mediated improvements in ventilation were directly correlated with improved respiration, we used UWBP to quantitatively evaluate nine additional aminopyridines in BoNT/A-intoxicated mice. Multiple aminopyridines were identified with comparable or enhanced therapeutic efficacies compared with 3,4-DAP, including aminopyridines that selectively improved tidal volume versus respiratory rate and vice versa. In addition to contributing to a growing body of evidence supporting the use of aminopyridines to treat clinical botulism, these data lay the groundwork for the development of aminopyridine derivatives with improved pharmacological properties. SIGNIFICANCE STATEMENT: There is a critical need for fast-acting treatments to reverse respiratory paralysis in patients with botulism. This study used unrestrained, whole-body plethysmography and arterial blood gas analysis to show that aminopyridines rapidly restore ventilation and respiration and reverse respiratory acidosis when administered to mice at terminal stages of botulism. In addition to supporting the use of aminopyridines as first-line treatments for botulism symptoms, these data are expected to contribute to the development of new aminopyridine derivatives with improved pharmacological properties.
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Affiliation(s)
- William T McClintic
- Wake Forest Institute for Regenerative Medicine, Wake Forest University Health Sciences, Winston-Salem, North Carolina
| | - Zachary D Chandler
- Wake Forest Institute for Regenerative Medicine, Wake Forest University Health Sciences, Winston-Salem, North Carolina
| | - Lalitha M Karchalla
- Wake Forest Institute for Regenerative Medicine, Wake Forest University Health Sciences, Winston-Salem, North Carolina
| | - Celinia A Ondeck
- Wake Forest Institute for Regenerative Medicine, Wake Forest University Health Sciences, Winston-Salem, North Carolina
| | - Sean W O'Brien
- Wake Forest Institute for Regenerative Medicine, Wake Forest University Health Sciences, Winston-Salem, North Carolina
| | - Charity J Campbell
- Wake Forest Institute for Regenerative Medicine, Wake Forest University Health Sciences, Winston-Salem, North Carolina
| | - Alan R Jacobson
- Wake Forest Institute for Regenerative Medicine, Wake Forest University Health Sciences, Winston-Salem, North Carolina
| | - Patrick M McNutt
- Wake Forest Institute for Regenerative Medicine, Wake Forest University Health Sciences, Winston-Salem, North Carolina
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5
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Zhao R, Qasim A, Sophanpanichkul P, Dai H, Nayak M, Sher I, Chill J, Goldstein SAN. Selective block of human Kv1.1 channels and an epilepsy-associated gain-of-function mutation by AETX-K peptide. FASEB J 2024; 38:e23381. [PMID: 38102952 PMCID: PMC10754259 DOI: 10.1096/fj.202302061r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 11/11/2023] [Accepted: 12/05/2023] [Indexed: 12/17/2023]
Abstract
Dysfunction of the human voltage-gated K+ channel Kv1.1 has been associated with epilepsy, multiple sclerosis, episodic ataxia, myokymia, and cardiorespiratory dysregulation. We report here that AETX-K, a sea anemone type I (SAK1) peptide toxin we isolated from a phage display library, blocks Kv1.1 with high affinity (Ki ~ 1.6 pM) and notable specificity, inhibiting other Kv channels we tested a million-fold less well. Nuclear magnetic resonance (NMR) was employed both to determine the three-dimensional structure of AETX-K, showing it to employ a classic SAK1 scaffold while exhibiting a unique electrostatic potential surface, and to visualize AETX-K bound to the Kv1.1 pore domain embedded in lipoprotein nanodiscs. Study of Kv1.1 in Xenopus oocytes with AETX-K and point variants using electrophysiology demonstrated the blocking mechanism to employ a toxin-channel configuration we have described before whereby AETX-K Lys23 , two positions away on the toxin interaction surface from the classical blocking residue, enters the pore deeply enough to interact with K+ ions traversing the pathway from the opposite side of the membrane. The mutant channel Kv1.1-L296 F is associated with pharmaco-resistant multifocal epilepsy in infants because it significantly increases K+ currents by facilitating opening and slowing closure of the channels. Consistent with the therapeutic potential of AETX-K for Kv1.1 gain-of-function-associated diseases, AETX-K at 4 pM decreased Kv1.1-L296 F currents to wild-type levels; further, populations of heteromeric channels formed by co-expression Kv1.1 and Kv1.2, as found in many neurons, showed a Ki of ~10 nM even though homomeric Kv1.2 channels were insensitive to the toxin (Ki > 2000 nM).
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Affiliation(s)
- Ruiming Zhao
- Departments of Pediatrics, Physiology & Biophysics, and Pharmaceutical Sciences, Susan and Henry Samueli College of Health Sciences, University of California, Irvine, Irvine, CA 92697, USA
| | - Arwa Qasim
- Department of Chemistry, Bar Ilan University, Ramat Gan, 52900, Israel
| | - Punyanuch Sophanpanichkul
- Departments of Pediatrics, Physiology & Biophysics, and Pharmaceutical Sciences, Susan and Henry Samueli College of Health Sciences, University of California, Irvine, Irvine, CA 92697, USA
| | - Hui Dai
- Departments of Pediatrics, Physiology & Biophysics, and Pharmaceutical Sciences, Susan and Henry Samueli College of Health Sciences, University of California, Irvine, Irvine, CA 92697, USA
| | - Maha Nayak
- Departments of Pediatrics, Physiology & Biophysics, and Pharmaceutical Sciences, Susan and Henry Samueli College of Health Sciences, University of California, Irvine, Irvine, CA 92697, USA
| | - Inbal Sher
- Department of Chemistry, Bar Ilan University, Ramat Gan, 52900, Israel
| | - Jordan Chill
- Department of Chemistry, Bar Ilan University, Ramat Gan, 52900, Israel
| | - Steve A. N. Goldstein
- Departments of Pediatrics, Physiology & Biophysics, and Pharmaceutical Sciences, Susan and Henry Samueli College of Health Sciences, University of California, Irvine, Irvine, CA 92697, USA
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6
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Selcuk Muhtaroglu F, Belgen Kaygisiz B, Usar Incirli S, Kahraman T. Dalfampridine as a promising agent in the management of hereditary spastic paraplegia: A triple-blinded, randomized, placebo-controlled pilot trial. J Clin Neurosci 2023; 117:136-142. [PMID: 37804674 DOI: 10.1016/j.jocn.2023.09.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 09/20/2023] [Accepted: 09/28/2023] [Indexed: 10/09/2023]
Abstract
Limited but encouraging results support the use of dalfampridine in patients with hereditary spastic paraplegia (HSP). Our aim was to investigate the effects of dalfampridine on walking speed, muscle length, spasticity, functional strength, and functional mobility in patients with HSP. In this triple-blinded, randomized, placebo-controlled pilot trial, four patients with HSP received dalfampridine (10 mg twice daily) in addition to physiotherapy (twice a week), and four patients received placebo in addition to physiotherapy for eight weeks. The group allocation was masked from the assessor, treating physiotherapists, and patients. The primary outcome was the Timed 25-foot Walk Test (T25FWT) at the end of the eight-week treatment. The secondary outcome measures were functional mobility, functional muscle strength, muscle length, and spasticity. The improvement in the T25FWT values was significantly higher in the experimental group than in the control group (p < 0.05). All patients in the experimental group exceeded the proposed minimally important clinical difference for T25FWT. The degrees of improvement in most muscle length and spasticity assessments and functional muscle strength were also higher in the experimental group (p < 0.05). No significant difference was observed between the groups regarding functional mobility (p > 0.05). No adverse events or side effects were noted. This pilot trial yields encouraging evidence that the combination of dalfampridine and physiotherapy may enhance muscle parameters and improve walking speed in patients with HSP. However, further research involving larger sample sizes and more comprehensive assessments is needed to validate these results and establish the clinical benefits of this treatment approach. Trial registration ID: NCT05613114 (https://clinicaltrials.gov/), retrospectively registered on November 14, 2022.
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Affiliation(s)
- Ferda Selcuk Muhtaroglu
- Vocational School of Health Services, European University of Lefke, Lefke, Cyprus; Department of Neurology, Dr Burhan Nalbantoglu State Hospital, Nicosia, Cyprus
| | - Beliz Belgen Kaygisiz
- Department of Physiotherapy and Rehabilitation, Faculty of Health Sciences, European University of Lefke, Lefke, Cyprus
| | - Sila Usar Incirli
- Department of Neurology, Dr Burhan Nalbantoglu State Hospital, Nicosia, Cyprus
| | - Turhan Kahraman
- Department of Health Professions, Faculty of Health and Education, Manchester Metropolitan University, Manchester, United Kingdom; Department of Physiotherapy and Rehabilitation, Faculty of Health Sciences, Izmir Katip Celebi University, Izmir, Turkey.
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7
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Ashokan A, Nehru J, Chakkarapani N, Khamrang T, Kavitha SJ, Rajakannan V, Hemamalini M. 4-Amino-3,5-di-chloro-pyridinium 3-hy-droxy-pico-linate monohydrate. IUCRDATA 2023; 8:x230821. [PMID: 37818469 PMCID: PMC10561231 DOI: 10.1107/s2414314623008210] [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: 09/15/2023] [Accepted: 09/19/2023] [Indexed: 10/12/2023] Open
Abstract
In the title hydrated salt, C5H5Cl2N2 +·C6H4NO3 -·H2O, the pyridine N atom of the cation is protonated and an intra-molecular O-H⋯O hydrogen bond is observed in the anion, which generates an S(6) ring. The crystal packing features N-H⋯N, O-H⋯O, N-H⋯O, C-H⋯Cl and C-H⋯O hydrogen bonds, which generate a three-dimensional network.
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Affiliation(s)
- Agalya Ashokan
- Department of Chemistry, Mother Teresa Women’s University, Kodaikanal, Tamil Nadu, India
| | - Jayasudha Nehru
- Department of Chemistry, Mother Teresa Women’s University, Kodaikanal, Tamil Nadu, India
| | - Nandhini Chakkarapani
- Department of Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai-600 025, Tamil Nadu, India
| | - Themmila Khamrang
- Assistant Professor, Department of Chemistry, DM College of Science, Dhanamanjuri University, Imphal, Manipur-795 001, India
| | | | - Venkatachalam Rajakannan
- Department of Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai-600 025, Tamil Nadu, India
| | - Madhukar Hemamalini
- Department of Chemistry, Mother Teresa Women’s University, Kodaikanal, Tamil Nadu, India
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8
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Ghorbanpour S, Rahimibarghani S, Rohani S, Rastkar M, Ghajarzadeh M. Fampridine for gait imbalance in patients with multiple sclerosis (MS): a systematic review and meta-analysis. Neurol Sci 2023; 44:3059-3069. [PMID: 37055710 DOI: 10.1007/s10072-023-06795-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 04/05/2023] [Indexed: 04/15/2023]
Abstract
BACKGROUND Gait imbalance is one of the frequent complications in subjects with multiple sclerosis (MS). Fampridine (4-aminopyridine) is a potassium-channel blocker that is administered for gait imbalance in MS. Different studies showed the effects of fampridine on gait status based on various tests in subjects with MS. Some showed significant improvement after treatment, and others did not. So, we designed this systematic review, and meta-analysis to estimate the pooled effects of fampridine on gait status in patients with MS. METHODS The main goal is the evaluation of times of different gait test pre and post fampridine treatment. Two independent expert researchers conducted a systematic and comprehensive search in PubMed, Scopus, EMBASE, Web of Science, and Google Scholar and also gray literature, including references of the references and conference abstracts. The search was done on September 16, 2022. Before-after studies trials reporting scores of the walking tests. We extracted data regarding the total number of participants, first author, publication year, country of origin, mean age, Expanded Disability Status Scale (EDSS), and the results of walking tests. RESULTS The literature search revealed 1963 studies; after deleting duplicates, 1098 studies remained. Seventy-seven full texts were evaluated. Finally, 18 studies were included for meta-analysis, while most of them were not placebo-controlled trials. The most frequent country of origin was Germany, and the mean age and EDSS ranged between 44 and 56 years and 4 and 6, respectively. The studies were published between 2013 and 2019. The pooled standardized mean difference (SMD) (after-before) of the MS Walking Scale (MSWS-12) was - 1.97 (95%CI: - 1.7, - 1.03) (I2 = 93.1%, P < 0.001). The pooled SMD (after-before) of the six-minute walk test (6MWT) was 0.49 (95%CI: 0.22, - 0.76) (I2 = 0%, P = 0.7). The pooled SMD (after-before) of T Timed 25-Foot Walk (T25FW) was - 0.99(95%CI: - 1.52, - 0.47) (I2 = 97.5%, P < 0.001). CONCLUSION This systematic review and meta-analysis show that fampridine improves gait imbalance in patients with MS.
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Affiliation(s)
- Sahar Ghorbanpour
- Department of Physical Medicine and Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran
| | - Sarvenaz Rahimibarghani
- Department of Physical Medicine and Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran
| | - Setareh Rohani
- Department of Physical Medicine and Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohsen Rastkar
- Student's Scientific Research Center, Tehran University of Medical Sciences, Tehran, Mahsa Ghajarzadeh, Iran
| | - Mahsa Ghajarzadeh
- Department of Neurology, Johns Hopkins University, Baltimore, MD, USA.
- Multiple Sclerosis Research Group (MSRG), Universal Scientific Education and Research Network (USERN), Tehran University of Medical Sciences, Tehran, Iran.
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9
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Koutsouraki E, Theodoros K, Eleni G, Marianna K, Areti N, Ariadni K, Dimitrios M. Autonomic nervous system disorders in multiple sclerosis. J Neurol 2023:10.1007/s00415-023-11725-y. [PMID: 37084150 DOI: 10.1007/s00415-023-11725-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 04/11/2023] [Accepted: 04/12/2023] [Indexed: 04/22/2023]
Abstract
Multiple sclerosis (MS) is a chronic progressive demyelinating disease of the central nervous system (CNS), which also affects the autonomic nervous system (ANS). Manifestations of MS in the ANS include urological, sexual, gastrointestinal, cardiovascular, and thermoregulatory disorders as well as increased fatigue. These problems are common yet are often underestimated due to the non-specificity of the symptoms and the limited evaluation of the ANS in the usual clinical practice. Most of these symptoms seem to be related to localized lesions in the CNS. However, the mechanisms by which these disorders are caused in MS have not been fully investigated, thus preventing any focused etiological treatment. The most common disorders of the ANS in MS represent a challenge for clinicians due to the variability of the clinical picture and our minimal data on their diagnosis and treatment. Early diagnosis and initiation of individualized treatment regimens, often in need of multiple approaches, seem to yield the best results in managing ANS dysfunction in MS patients.
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Affiliation(s)
- Effrosyni Koutsouraki
- First Department of Neurology, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece.
| | | | | | | | | | - Koukoulidou Ariadni
- Nursing School, International University of Greece, Sindos, Thessaloniki, Greece
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10
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Mechanism of 4-aminopyridine inhibition of the lysosomal channel TMEM175. Proc Natl Acad Sci U S A 2022; 119:e2208882119. [PMID: 36279431 PMCID: PMC9636928 DOI: 10.1073/pnas.2208882119] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Transmembrane protein 175 (TMEM175) is an evolutionarily distinct lysosomal cation channel whose mutation is associated with the development of Parkinson’s disease. Here, we present a cryoelectron microscopy structure and molecular simulations of TMEM175 bound to 4-aminopyridine (4-AP), the only known small-molecule inhibitor of TMEM175 and a broad K
+
channel inhibitor, as well as a drug approved by the Food and Drug Administration against multiple sclerosis. The structure shows that 4-AP, whose mode of action had not been previously visualized, binds near the center of the ion conduction pathway, in the open state of the channel. Molecular dynamics simulations reveal that this binding site is near the middle of the transmembrane potential gradient, providing a rationale for the voltage-dependent dissociation of 4-AP from TMEM175. Interestingly, bound 4-AP rapidly switches between three predominant binding poses, stabilized by alternate interaction patterns dictated by the twofold symmetry of the channel. Despite this highly dynamic binding mode, bound 4-AP prevents not only ion permeation but also water flow. Together, these studies provide a framework for the rational design of novel small-molecule inhibitors of TMEM175 that might reveal the role of this channel in human lysosomal physiology both in health and disease.
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11
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Hupperts R, Gasperini C, Lycke J, Ziemssen T, Feys P, Xiao S, Acosta C, Koster T, Hobart J. Efficacy of prolonged-release fampridine versus placebo on walking ability, dynamic and static balance, physical impact of multiple sclerosis, and quality of life: an integrated analysis of MOBILE and ENHANCE. Ther Adv Neurol Disord 2022; 15:17562864221090398. [PMID: 35601756 PMCID: PMC9121513 DOI: 10.1177/17562864221090398] [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: 10/27/2021] [Accepted: 03/10/2022] [Indexed: 11/22/2022] Open
Abstract
Background: MOBILE and ENHANCE were similarly designed randomized trials of
walking-impaired adults with relapsing-remitting or progressive multiple
sclerosis (MS) who received placebo or 10 mg prolonged-release
(PR)-fampridine twice daily for 24 weeks. Both studies showed sustained and
clinically meaningful improvement in broad measures of walking and balance
over 24 weeks of PR-fampridine treatment. Objective: To evaluate the functional benefits and safety of PR-fampridine
versus placebo using a post hoc
integrated efficacy analysis of MOBILE and ENHANCE data. Methods: Data from the intention-to-treat (ITT) populations of MOBILE and ENHANCE
studies were pooled in a post hoc analysis based on the
following outcome measures: 12-item MS Walking Scale (MSWS-12), Timed Up and
Go (TUG) speed, Berg Balance Scale (BBS), MS Impact Scale physical impact
subscale (MSIS-29 PHYS), EQ-5D utility index score, visual analogue scale
(VAS), and adverse events. The primary analysis was the proportion of people
with MS (PwMS) with a mean improvement in MSWS-12 score (⩾8 points) from
baseline over 24 weeks. A subgroup analysis based on baseline
characteristics was performed. Findings: In the ITT population (N = 765; PR-fampridine,
n = 383; placebo, n = 382), a greater
proportion of PR-fampridine–treated PwMS than placebo-treated PwMS achieved
a clinically meaningful improvement in the MSWS-12 scale over 24 weeks
(44.3% versus 33.0%; p < 0.001).
PR-fampridine MSWS-12 responders demonstrated greater improvements from
baseline in TUG speed, BBS score, MSIS-29 PHYS score, and EQ-5D utility
index and VAS scores versus PR-fampridine MSWS-12
nonresponders and placebo. Subgroup analyses based on baseline
characteristics showed consistency in the effects of PR-fampridine. Conclusion: The pooled analysis of MOBILE and ENHANCE confirms previous evidence that
treatment with PR-fampridine results in clinically meaningful improvements
in walking, mobility and balance, self-reported physical impact of MS, and
quality of life and is effective across a broad range of PwMS.
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Affiliation(s)
- Raymond Hupperts
- Department of Neurology, Zuyderland Medical Center, 6130 MB Sittard, The Netherlands
| | - Claudio Gasperini
- Department of Neurosciences, S. Camillo Forlanini Hospital, Rome, Italy
| | - Jan Lycke
- Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy and Department of Neurology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Tjalf Ziemssen
- Center of Clinical Neuroscience, Carl Gustav Carus University Clinic, Technical University of Dresden, Dresden, Germany
| | - Peter Feys
- REVAL, Faculty of Rehabilitation Sciences, Hasselt University, Diepenbeek, Belgium; UMSC Hasselt, Pelt, Belgium
| | | | | | | | - Jeremy Hobart
- Plymouth University Peninsula Schools of Medicine and Dentistry, Plymouth Hospitals NHS Trust, Plymouth, UK
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12
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Radomski KL, Zi X, Lischka FW, Noble MD, Galdzicki Z, Armstrong RC. Acute axon damage and demyelination are mitigated by 4-aminopyridine (4-AP) therapy after experimental traumatic brain injury. Acta Neuropathol Commun 2022; 10:67. [PMID: 35501931 PMCID: PMC9059462 DOI: 10.1186/s40478-022-01366-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 04/11/2022] [Indexed: 11/10/2022] Open
Abstract
Damage to long axons in white matter tracts is a major pathology in closed head traumatic brain injury (TBI). Acute TBI treatments are needed that protect against axon damage and promote recovery of axon function to prevent long term symptoms and neurodegeneration. Our prior characterization of axon damage and demyelination after TBI led us to examine repurposing of 4-aminopyridine (4-AP), an FDA-approved inhibitor of voltage-gated potassium (Kv) channels. 4-AP is currently indicated to provide symptomatic relief for patients with chronic stage multiple sclerosis, which involves axon damage and demyelination. We tested clinically relevant dosage of 4-AP as an acute treatment for experimental TBI and found multiple benefits in corpus callosum axons. This randomized, controlled pre-clinical study focused on the first week after TBI, when axons are particularly vulnerable. 4-AP treatment initiated one day post-injury dramatically reduced axon damage detected by intra-axonal fluorescence accumulations in Thy1-YFP mice of both sexes. Detailed electron microscopy in C57BL/6 mice showed that 4-AP reduced pathological features of mitochondrial swelling, cytoskeletal disruption, and demyelination at 7 days post-injury. Furthermore, 4-AP improved the molecular organization of axon nodal regions by restoring disrupted paranode domains and reducing Kv1.2 channel dispersion. 4-AP treatment did not resolve deficits in action potential conduction across the corpus callosum, based on ex vivo electrophysiological recordings at 7 days post-TBI. Thus, this first study of 4-AP effects on axon damage in the acute period demonstrates a significant decrease in multiple pathological hallmarks of axon damage after experimental TBI.
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Affiliation(s)
- Kryslaine L. Radomski
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
- Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
| | - Xiaomei Zi
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
- Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
| | - Fritz W. Lischka
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
- Biomedical Instrumentation Center, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
| | - Mark D. Noble
- Department of Biomedical Genetics, School of Medicine and Dentistry, University of Rochester, 601 Elmwood Ave, Box 633, Rochester, NY 14642 USA
| | - Zygmunt Galdzicki
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
- Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
| | - Regina C. Armstrong
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
- Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
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13
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Louzao MC, Vilariño N, Vale C, Costas C, Cao A, Raposo-Garcia S, Vieytes MR, Botana LM. Current Trends and New Challenges in Marine Phycotoxins. Mar Drugs 2022; 20:md20030198. [PMID: 35323497 PMCID: PMC8950113 DOI: 10.3390/md20030198] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/04/2022] [Accepted: 03/05/2022] [Indexed: 02/04/2023] Open
Abstract
Marine phycotoxins are a multiplicity of bioactive compounds which are produced by microalgae and bioaccumulate in the marine food web. Phycotoxins affect the ecosystem, pose a threat to human health, and have important economic effects on aquaculture and tourism worldwide. However, human health and food safety have been the primary concerns when considering the impacts of phycotoxins. Phycotoxins toxicity information, often used to set regulatory limits for these toxins in shellfish, lacks traceability of toxicity values highlighting the need for predefined toxicological criteria. Toxicity data together with adequate detection methods for monitoring procedures are crucial to protect human health. However, despite technological advances, there are still methodological uncertainties and high demand for universal phycotoxin detectors. This review focuses on these topics, including uncertainties of climate change, providing an overview of the current information as well as future perspectives.
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Affiliation(s)
- Maria Carmen Louzao
- Departamento de Farmacologia, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain; (N.V.); (C.V.); (C.C.); (A.C.); (S.R.-G.)
- Correspondence: (M.C.L.); (L.M.B.)
| | - Natalia Vilariño
- Departamento de Farmacologia, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain; (N.V.); (C.V.); (C.C.); (A.C.); (S.R.-G.)
| | - Carmen Vale
- Departamento de Farmacologia, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain; (N.V.); (C.V.); (C.C.); (A.C.); (S.R.-G.)
| | - Celia Costas
- Departamento de Farmacologia, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain; (N.V.); (C.V.); (C.C.); (A.C.); (S.R.-G.)
| | - Alejandro Cao
- Departamento de Farmacologia, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain; (N.V.); (C.V.); (C.C.); (A.C.); (S.R.-G.)
| | - Sandra Raposo-Garcia
- Departamento de Farmacologia, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain; (N.V.); (C.V.); (C.C.); (A.C.); (S.R.-G.)
| | - Mercedes R. Vieytes
- Departamento de Fisiologia, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain;
| | - Luis M. Botana
- Departamento de Farmacologia, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain; (N.V.); (C.V.); (C.C.); (A.C.); (S.R.-G.)
- Correspondence: (M.C.L.); (L.M.B.)
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14
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Clifford AM, Tresguerres M, Goss GG, Wood CM. A novel K + -dependent Na + uptake mechanism during low pH exposure in adult zebrafish (Danio rerio): New tricks for old dogma. Acta Physiol (Oxf) 2022; 234:e13777. [PMID: 34985194 DOI: 10.1111/apha.13777] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 09/27/2021] [Accepted: 01/01/2022] [Indexed: 12/16/2022]
Abstract
AIM To determine whether Na+ uptake in adult zebrafish (Danio rerio) exposed to acidic water adheres to traditional models reliant on Na+ /H+ Exchangers (NHEs), Na+ channels and Na+ /Cl- Cotransporters (NCCs) or if it occurs through a novel mechanism. METHODS Zebrafish were exposed to control (pH 8.0) or acidic (pH 4.0) water for 0-12 hours during which 22 Na+ uptake ( J Na in ), ammonia excretion, net acidic equivalent flux and net K+ flux ( J H net ) were measured. The involvement of NHEs, Na+ channels, NCCs, K+ -channels and K+ -dependent Na+ /Ca2+ exchangers (NCKXs) was evaluated by exposure to Cl- -free or elevated [K+ ] water, or to pharmacological inhibitors. The presence of NCKXs in gill was examined using RT-PCR. RESULTS J Na in was strongly attenuated by acid exposure, but gradually recovered to control rates. The systematic elimination of each of the traditional models led us to consider K+ as a counter substrate for Na+ uptake during acid exposure. Indeed, elevated environmental [K+ ] inhibited J Na in during acid exposure in a concentration-dependent manner, with near-complete inhibition at 10 mM. Moreover, J H net loss increased approximately fourfold at 8-10 hours of acid exposure which correlated with recovered J Na in in 1:1 fashion, and both J Na in and J H net were sensitive to tetraethylammonium (TEA) during acid exposure. Zebrafish gills expressed mRNA coding for six NCKX isoforms. CONCLUSIONS During acid exposure, zebrafish engage a novel Na+ uptake mechanism that utilizes the outwardly directed K+ gradient as a counter-substrate for Na+ and is sensitive to TEA. NKCXs are promising candidates to mediate this K+ -dependent Na+ uptake, opening new research avenues about Na+ uptake in zebrafish and other acid-tolerant aquatic species.
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Affiliation(s)
- Alexander M. Clifford
- Department of Zoology University of British Columbia Vancouver British Columbia Canada
- Marine Biology Research Division Scripps Institution of Oceanography University of California San Diego La Jolla California USA
| | - Martin Tresguerres
- Marine Biology Research Division Scripps Institution of Oceanography University of California San Diego La Jolla California USA
| | - Greg G. Goss
- Department of Biological Sciences University of Alberta Edmonton Alberta Canada
| | - Chris M. Wood
- Department of Zoology University of British Columbia Vancouver British Columbia Canada
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15
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Brundage JN, Mason CP, Wadsworth HA, Finuf CS, Nelson JJ, Ronström PJW, Jones SR, Siciliano CA, Steffensen SC, Yorgason JT. Regional and sex differences in spontaneous striatal dopamine transmission. J Neurochem 2022; 160:598-612. [PMID: 34265080 PMCID: PMC10044475 DOI: 10.1111/jnc.15473] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 06/10/2021] [Accepted: 07/13/2021] [Indexed: 11/29/2022]
Abstract
Striatal dopamine release is key for learning and motivation and is composed of subregions including the dorsal striatum (DS), nucleus accumbens core, and the nucleus accumbens shell. Spontaneously occurring dopamine release was compared across these subregions. Dopamine release/uptake dynamics differ across striatal subregions, with dopamine transient release amplitude and release frequency greatest in male mice, and the largest signals observed in the DS. Surprisingly, female mice exhibited little regional differences in dopamine release for DS and nucleus accumbens core regions, but lower release in the nucleus accumbens shell. Blocking voltage-gated K+ channel (Kv channels) with 4-aminopyridine enhanced dopamine detection without affecting reuptake. The 4-aminopyridine effects were greatest in ventral regions of female mice, suggesting regional differences in Kv channel expression. The dopamine transporter blocker cocaine also enhanced detection across subregions in both sexes, with greater overall increased release in females than males. Thus, sex differences in dopamine transmission are apparent and likely include differences in the Kv channel and dopamine transporter function. The lack of regional differences in dopamine release observed in females indicates differential regulation of spontaneous and evoked dopamine release.
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Affiliation(s)
| | - Colin P. Mason
- Neuroscience Center, Brigham Young University, Provo, UT, USA
| | | | - Chris S. Finuf
- Department of Psychology and Neuroscience Center, Brigham Young University, Provo, UT, USA
| | - Josh J. Nelson
- Neuroscience Center, Brigham Young University, Provo, UT, USA
| | | | - Sara R. Jones
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, NC, USA
| | - Cody A. Siciliano
- Department of Pharmacology, Vanderbilt Brain Institute, Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, TN, USA
| | - Scott C. Steffensen
- Department of Psychology and Neuroscience Center, Brigham Young University, Provo, UT, USA
| | - Jordan T. Yorgason
- Neuroscience Center, Brigham Young University, Provo, UT, USA
- Department of Cellular Biology and Physiology, Brigham Young University, Provo, UT, USA
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16
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Moussaoui H, Ladjel-Mendil A, Laraba-Djebari F. Neuromodulation of neurological disorders in a demyelination model: effect of a potassium channel inhibitor from Androctonus scorpion venom. TOXIN REV 2022. [DOI: 10.1080/15569543.2021.2022698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Hadjila Moussaoui
- Faculty of Biological Sciences, USTHB, Laboratory of Cellular and Molecular Biology, Algiers, Algeria
| | - Amina Ladjel-Mendil
- Faculty of Biological Sciences, USTHB, Laboratory of Cellular and Molecular Biology, Algiers, Algeria
| | - Fatima Laraba-Djebari
- Faculty of Biological Sciences, USTHB, Laboratory of Cellular and Molecular Biology, Algiers, Algeria
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17
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Mamoei S, Jensen HB, Pedersen AK, Nygaard MKE, Eskildsen SF, Dalgas U, Stenager E. Clinical, Neurophysiological, and MRI Markers of Fampridine Responsiveness in Multiple Sclerosis-An Explorative Study. Front Neurol 2021; 12:758710. [PMID: 34764932 PMCID: PMC8576138 DOI: 10.3389/fneur.2021.758710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Accepted: 09/16/2021] [Indexed: 01/18/2023] Open
Abstract
Objective: Persons with multiple sclerosis (PwMS), already established as responders or non-responders to Fampridine treatment, were compared in terms of disability measures, physical and cognitive performance tests, neurophysiology, and magnetic resonance imaging (MRI) outcomes in a 1-year explorative longitudinal study. Materials and Methods: Data from a 1-year longitudinal study were analyzed. Examinations consisted of the timed 25-foot walk test (T25FW), six spot step test (SSST), nine-hole peg test (9-HPT), five times sit-to-stand test (5-STS), symbol digit modalities test (SDMT), transcranial magnetic stimulation (TMS) elicited motor evoked potentials (MEP) examining central motor conduction times (CMCT), peripheral motor conduction times (PMCT) and their amplitudes, electroneuronography (ENG) of the lower extremities, and brain structural MRI measures. Results: Forty-one responders and eight non-responders to Fampridine treatment were examined. There were no intergroup differences except for the PMCT, where non-responders had prolonged conduction times compared to responders to Fampridine. Six spot step test was associated with CMCT throughout the study. After 1 year, CMCT was further prolonged and cortical MEP amplitudes decreased in both groups, while PMCT and ENG did not change. Throughout the study, CMCT was associated with the expanded disability status scale (EDSS) and 12-item multiple sclerosis walking scale (MSWS-12), while SDMT was associated with number of T2-weighted lesions, lesion load, and lesion load normalized to brain volume. Conclusions: Peripheral motor conduction time is prolonged in non-responders to Fampridine when compared to responders. Transcranial magnetic stimulation-elicited MEPs and SDMT can be used as markers of disability progression and lesion activity visualized by MRI, respectively. Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT03401307.
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Affiliation(s)
- Sepehr Mamoei
- Department of Regional Health Research, University of Southern Denmark, Odense, Denmark.,Department of Neurology, University Hospital of Southern Jutland, Sønderborg, Denmark.,Open Patient Data Explorative Network, Odense, Denmark.,Neurological Research Unit, MS Clinics of Southern Jutland (Sønderborg, Esbjerg, Kolding), University Hospital of Southern Jutland, Aabenraa, Denmark
| | - Henrik Boye Jensen
- Department of Regional Health Research, University of Southern Denmark, Odense, Denmark.,Open Patient Data Explorative Network, Odense, Denmark.,Department of Brain and Nerve Diseases, University Hospital of Lillebælt, Kolding, Denmark
| | | | - Mikkel Karl Emil Nygaard
- Center of Functionally Integrative Neuroscience (CFIN), Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Simon Fristed Eskildsen
- Center of Functionally Integrative Neuroscience (CFIN), Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Ulrik Dalgas
- Exercise Biology, Department of Public Health, Aarhus University, Aarhus, Denmark
| | - Egon Stenager
- Department of Regional Health Research, University of Southern Denmark, Odense, Denmark.,Department of Neurology, University Hospital of Southern Jutland, Sønderborg, Denmark.,Neurological Research Unit, MS Clinics of Southern Jutland (Sønderborg, Esbjerg, Kolding), University Hospital of Southern Jutland, Aabenraa, Denmark
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18
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Sancho M, Kyle BD. The Large-Conductance, Calcium-Activated Potassium Channel: A Big Key Regulator of Cell Physiology. Front Physiol 2021; 12:750615. [PMID: 34744788 PMCID: PMC8567177 DOI: 10.3389/fphys.2021.750615] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/29/2021] [Indexed: 12/01/2022] Open
Abstract
Large-conductance Ca2+-activated K+ channels facilitate the efflux of K+ ions from a variety of cells and tissues following channel activation. It is now recognized that BK channels undergo a wide range of pre- and post-translational modifications that can dramatically alter their properties and function. This has downstream consequences in affecting cell and tissue excitability, and therefore, function. While finding the “silver bullet” in terms of clinical therapy has remained elusive, ongoing research is providing an impressive range of viable candidate proteins and mechanisms that associate with and modulate BK channel activity, respectively. Here, we provide the hallmarks of BK channel structure and function generally, and discuss important milestones in the efforts to further elucidate the diverse properties of BK channels in its many forms.
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Affiliation(s)
- Maria Sancho
- Department of Pharmacology, University of Vermont, Burlington, VT, United States
| | - Barry D Kyle
- Department of Pathology and Laboratory Medicine, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
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19
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Kostadinova I, Landzhov B, Marinov L, Vezenkov L, Danchev N. Neuroprotective effect of newly synthesized 4-aminopyridine derivatives on cuprizone-induced demyelination in mice-a behavioral and immunohistochemical study. Amino Acids 2021; 53:1279-1286. [PMID: 34240251 DOI: 10.1007/s00726-021-03035-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 06/30/2021] [Indexed: 11/30/2022]
Abstract
The aim of this study was to assess the effect of newly synthesized derivatives of 4-aminopyridine (4-AP) on cuprizone-induced model of brain demyelination in mice. 4-AP is already approved for the treatment of walking difficulties in patients with multiple sclerosis. The model of demyelination was carried out by the administration of cuprizone to the drinking water of the experimental mice. Besides cuprizone, 4-AP derivatives and 4-AP were administered to the groups in order to assess their protective effect on the demyelination. We used immunohistochemistry for visualization of changes in corpus callosum. Memory storage processes were also assessed with the passive avoidance test on the last two days of the experiment. The experimental mice treated with compounds 4b and 4c increased significantly their latency time on the second day in comparison to the control group which indicated an improved memory process. The number of mature oligodendrocytes in the groups treated with compounds 4b, 4c and 4-AP is closer to those in the control group. The results of our studies showed that the newly synthesized compounds 4b and 4c reverse the effect of cuprizone. These groups also showed increased latency time in the passive avoidance test in comparison to the control group.
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Affiliation(s)
- Ivanka Kostadinova
- Department of Pharmacology, Pharmacotherapy and Toxicology, Faculty of Pharmacy, Medical University of Sofia, 2 Dunav Str., 1000, Sofia, Bulgaria.
| | - Boycho Landzhov
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, Medical University of Sofia, 2 Zdrave Str., 1431, Sofia, Bulgaria
| | - Lyubomir Marinov
- Department of Pharmacology, Pharmacotherapy and Toxicology, Faculty of Pharmacy, Medical University of Sofia, 2 Dunav Str., 1000, Sofia, Bulgaria
| | - Lyubomir Vezenkov
- Department of Organic Chemistry, University of Chemical Technology and Metallurgy, 8 St. Kliment Ohridski Blvd., 1756, Sofia, Bulgaria
| | - Nikolai Danchev
- Department of Pharmacology, Pharmacotherapy and Toxicology, Faculty of Pharmacy, Medical University of Sofia, 2 Dunav Str., 1000, Sofia, Bulgaria
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20
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Chitra R, Choudhury R, Capet F, Roussel P, Bhatt P. Crystal structure of 4-aminopyridinium 3-(4-aminopyridinium) succinate tetra hydrate: A new salt from 4-aminopyridine and maleic acid crystallization. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2021.130142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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21
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Manoukian OS, Rudraiah S, Arul MR, Bartley JM, Baker JT, Yu X, Kumbar SG. Biopolymer-nanotube nerve guidance conduit drug delivery for peripheral nerve regeneration: In vivo structural and functional assessment. Bioact Mater 2021; 6:2881-2893. [PMID: 33718669 PMCID: PMC7907220 DOI: 10.1016/j.bioactmat.2021.02.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/12/2021] [Accepted: 02/12/2021] [Indexed: 01/01/2023] Open
Abstract
Peripheral nerve injuries account for roughly 3% of all trauma patients with over 900,000 repair procedures annually in the US. Of all extremity peripheral nerve injuries, 51% require nerve repair with a transected gap. The current gold-standard treatment for peripheral nerve injuries, autograft repair, has several shortcomings. Engineered constructs are currently only suitable for short gaps or small diameter nerves. Here, we investigate novel nerve guidance conduits with aligned microchannel porosity that deliver sustained-release of neurogenic 4-aminopyridine (4-AP) for peripheral nerve regeneration in a critical-size (15 mm) rat sciatic nerve transection model. The results of functional walking track analysis, morphometric evaluations of myelin development, and histological assessments of various markers confirmed the equivalency of our drug-conduit with autograft controls. Repaired nerves showed formation of thick myelin, presence of S100 and neurofilament markers, and promising functional recovery. The conduit's aligned microchannel architecture may play a vital role in physically guiding axons for distal target reinnervation, while the sustained release of 4-AP may increase nerve conduction, and in turn synaptic neurotransmitter release and upregulation of critical Schwann cell neurotrophic factors. Overall, our nerve construct design facilitates efficient and efficacious peripheral nerve regeneration via a drug delivery system that is feasible for clinical applications. Nerve guidance conduit platform with tunable scaffold properties for repair and regeneration of large-gap nerve injuries. Sustained 4-aminopyridine release amplifies neurotrophic factor release by Schwann cells to promote axon regeneration. Longitudinally aligned scaffold pores and controllable physicochemical properties provide guidance for axon regeneration. Critical-size rat sciatic nerve defect healing both structurally and functionally resembled autograft control treatment. Innovative and transformative scaffold technology imbued with structural and functional features for tissue regeneration. Scaffold enable tailorable release profiles for small molecules proteins and electrical stimulation for tissue regeneration.
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Affiliation(s)
- Ohan S Manoukian
- Department of Biomedical Engineering, University of Connecticut, Storrs, CT, USA.,Department of Orthopedic Surgery, University of Connecticut Health, Farmington, CT, USA
| | - Swetha Rudraiah
- Department of Orthopedic Surgery, University of Connecticut Health, Farmington, CT, USA.,Department of Pharmaceutical Sciences, University of Saint Joseph, Hartford, CT, USA
| | - Michael R Arul
- Department of Orthopedic Surgery, University of Connecticut Health, Farmington, CT, USA
| | - Jenna M Bartley
- Department of Immunology, Center on Aging, University of Connecticut Health, Farmington, CT, USA
| | - Jiana T Baker
- Department of Orthopedic Surgery, University of Connecticut Health, Farmington, CT, USA
| | - Xiaojun Yu
- Department of Biomedical Engineering, Stevens Institute of Technology, Hoboken, NJ, USA
| | - Sangamesh G Kumbar
- Department of Biomedical Engineering, University of Connecticut, Storrs, CT, USA.,Department of Orthopedic Surgery, University of Connecticut Health, Farmington, CT, USA
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22
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Assembly and Function of the Juxtaparanodal Kv1 Complex in Health and Disease. Life (Basel) 2020; 11:life11010008. [PMID: 33374190 PMCID: PMC7824554 DOI: 10.3390/life11010008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 12/21/2020] [Accepted: 12/23/2020] [Indexed: 02/07/2023] Open
Abstract
The precise axonal distribution of specific potassium channels is known to secure the shape and frequency of action potentials in myelinated fibers. The low-threshold voltage-gated Kv1 channels located at the axon initial segment have a significant influence on spike initiation and waveform. Their role remains partially understood at the juxtaparanodes where they are trapped under the compact myelin bordering the nodes of Ranvier in physiological conditions. However, the exposure of Kv1 channels in de- or dys-myelinating neuropathy results in alteration of saltatory conduction. Moreover, cell adhesion molecules associated with the Kv1 complex, including Caspr2, Contactin2, and LGI1, are target antigens in autoimmune diseases associated with hyperexcitability such as encephalitis, neuromyotonia, or neuropathic pain. The clustering of Kv1.1/Kv1.2 channels at the axon initial segment and juxtaparanodes is based on interactions with cell adhesion molecules and cytoskeletal linkers. This review will focus on the trafficking and assembly of the axonal Kv1 complex in the peripheral and central nervous system (PNS and CNS), during development, and in health and disease.
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Sarkar J, Chakraborti T, Pramanik PK, Ghosh P, Mandal A, Chakraborti S. PKCζ-NADPH Oxidase-PKCα Dependent Kv1.5 Phosphorylation by Endothelin-1 Modulates Nav1.5-NCX1-Cav1.2 Axis in Stimulating Ca 2+ Level in Caveolae of Pulmonary Artery Smooth Muscle Cells. Cell Biochem Biophys 2020; 79:57-71. [PMID: 33095400 DOI: 10.1007/s12013-020-00954-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/13/2020] [Indexed: 11/29/2022]
Abstract
Endothelin-1 (ET-1) is a potent endogenously derived vasoconstrictor, which increases pulmonary hypertension via stimulation of [Ca2+]i level in pulmonary artery smooth muscle cells (PASMCs). In this communication, we sought to investigate the mechanism by which ET-1 causes stimulation of Ca2+ concentration in caveolae vesicles of bovine PASMCs (BPASMCs). ET-1 activates PKC-α in the caveolae vesicles by O2.- derived from PKCζ-NADPH oxidase dependent pathway. PKC-α phosphorylates Kv1.5 channels leading to a marked stimulation of Na+ and Ca2+ concentration in the caveolae vesicles. The stimulation of Ca2+ concentration in the caveolae vesicles by ET-1 occurs predominantly via Cav1.2 channels. Additionally, an increase in Na+ concentration by ET-1 due to stimulation of Nav1.5 channels marginally increases Ca2+ level in the caveolae vesicles via reverse-mode Na+/Ca2+ exchanger (NCX-1) and also through "slip-mode conductance" Nav1.5 channels. 4-AP, a well-known inhibitor of Kv channels, also increases Ca2+ concentration in the caveolae vesicles via Cav1.2 channels, reverse-mode NCX-1 and Nav1.5 channels by phosphorylation independent modulation of Kv1.5 channels without the involvement of PKCζ-NADPH oxidase-PKCα signaling axis. Overall, PKCζ-NADPH oxidase-PKCα dependent phosphorylation of Kv1.5 by ET-1 modulates Nav1.5-NCX1-Cav1.2 axis for stimulation of Ca2+ concentration in caveolae vesicles of BPASMCs, which provides a crucial mechanism for better understanding of ET-1-mediated modulation of pulmonary vascular tone.
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Affiliation(s)
- Jaganmay Sarkar
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani, West Bengal, 741235, India
| | - Tapati Chakraborti
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani, West Bengal, 741235, India
| | - Pijush Kanti Pramanik
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani, West Bengal, 741235, India
| | - Priyanka Ghosh
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani, West Bengal, 741235, India
| | - Amritlal Mandal
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani, West Bengal, 741235, India
| | - Sajal Chakraborti
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani, West Bengal, 741235, India.
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De Giglio L, Cortese F, Pennisi EM. Aminopiridines in the treatment of multiple sclerosis and other neurological disorders. Neurodegener Dis Manag 2020; 10:409-423. [PMID: 33054615 DOI: 10.2217/nmt-2020-0018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Symptomatic treatment has a great relevance for the management of patients with neurologic diseases, since it reduces disease burden and improves quality of life. Aminopyridines (APs) are a group of potassium (K+) channel blocking agents that exert their activity both at central nervous system level and on neuromuscular junction. This review describes the use of APs for the symptomatic treatment of neurological conditions. We will describe trials leading to the approval of the extended-release 4-aminopyridine for MS and evidence in support of the use in other neurological diseases.
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Affiliation(s)
- Laura De Giglio
- Department of Medicine, San Filippo Neri Hospital, Neurology Unit, Rome, Italy
| | - Francesca Cortese
- Department of Medicine, San Filippo Neri Hospital, Neurology Unit, Rome, Italy
| | - Elena Maria Pennisi
- Department of Medicine, San Filippo Neri Hospital, Neurology Unit, Rome, Italy
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Göbel K, Wiendl H. 4-aminopyridine is not just a symptomatic therapy, it has a neuroprotective effect – No. Mult Scler 2020; 26:1311-1312. [DOI: 10.1177/1352458520924267] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Kerstin Göbel
- Department of Neurology with Institute of Translational Neurology, University of Münster, Münster, Germany
| | - Heinz Wiendl
- Department of Neurology with Institute of Translational Neurology, University of Münster, Münster, Germany
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Chiriboga CA, Marra J, LaMarca NM, Young SD, Weimer LH, Levin B, McCabe B. Lack of effect on ambulation of dalfampridine-ER (4-AP) treatment in adult SMA patients. Neuromuscul Disord 2020; 30:693-700. [PMID: 32788051 DOI: 10.1016/j.nmd.2020.07.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 07/08/2020] [Accepted: 07/15/2020] [Indexed: 11/29/2022]
Abstract
SMA is a genetically determined motor system disorder that results in muscle weakness, selective motor neuron death, muscle atrophy, and impaired functional mobility. In SMA model systems, long-term treatment with 4-aminopyridine (4-AP) has been shown to improve motor function. To assess tolerability and preliminary efficacy of 4-AP on walking ability, endurance and EMG in adult ambulatory SMA patients, we conducted a double blind, placebo control, crossover pilot study with dalfampridine (4-AP, 10 mg BID). The study is comprised of a short-term (2 weeks) treatment arm with 1-week washout and a long-term (6 weeks) treatment arm with a 2-week washout. The primary outcome measure, for which the study was powered, was the 6 min walk test (6MWT, distance and percent fatigue); secondary outcome measures were the Hammersmith Functional Motor Scale Expanded (HFMSE), Manual Muscle Testing (MMT), Myometry with Hand held Dynamometry, HHD) and Quantitative Gait Analyses. We performed electrophysiology, including CMAP and H-reflex, during the short-term treatment trial. The mean age of the 11 participants enrolled was 37.7 ± 11.9 years; 54.5% were male. Dalfampridine was safe and well tolerated and no patient suffered a serious adverse event related to treatment. We observed no statistically significant positive effects of dalfampridine treatment on our primary functional motor outcome (6MWT distance, fatigue). Dalfampridine had a positive effects on H-reflex and H/M ratio but not on CMAP amplitude. The effect on the H-reflex is of interest, as it suggests dalfampridine may enhance neuronal activity, an effect observed in SMA Drosophila and mouse models at doses (mg/kg) not recommended for clinical use. Larger studies with dalfampridine in SMA patients are needed to confirm our findings, especially in light of studies in other populations showing drug effects in only a subset of patients.
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Affiliation(s)
- Claudia A Chiriboga
- Division of Child Neurology, Department of Neurology, Columbia College of Physicians and Surgeons, Columbia University Medical Center, 180 Fort Washington Avenue # 552, New York, NY 10032-3791, United States.
| | - Jonathan Marra
- Division of Child Neurology, Department of Neurology, Columbia College of Physicians and Surgeons, Columbia University Medical Center, 180 Fort Washington Avenue # 552, New York, NY 10032-3791, United States
| | - Nicole M LaMarca
- Division of Child Neurology, Department of Neurology, Columbia College of Physicians and Surgeons, Columbia University Medical Center, 180 Fort Washington Avenue # 552, New York, NY 10032-3791, United States
| | | | - Louis H Weimer
- Department of Neurology, Columbia College of Physicians and Surgeons, New York, NY, United States
| | - Bruce Levin
- Department of Biostatistics, Mailman School of Public Health, Columbia University, New York, NY, United States
| | - Brian McCabe
- Brain Mind Institute, EPFL, Lausanne, Switzerland
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Pfeiffer F, Benali A. Could non-invasive brain-stimulation prevent neuronal degeneration upon ion channel re-distribution and ion accumulation after demyelination? Neural Regen Res 2020; 15:1977-1980. [PMID: 32394944 PMCID: PMC7716036 DOI: 10.4103/1673-5374.282234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Fast and efficient transmission of electrical signals in the nervous system is mediated through myelinated nerve fibers. In neuronal diseases such as multiple sclerosis, the conduction properties of axons are disturbed by the removal of the myelin sheath, leaving nerve cells at a higher risk of degenerating. In some cases, the protective myelin sheath of axons can be rebuilt by remyelination through oligodendroglial cells. In any case, however, changes in the ion channel organization occur and may help to restore impulse conduction after demyelination. On the other hand, changes in ion channel distribution may increase the energy demand of axons, thereby increasing the probability of axonal degeneration. Many attempts have been made or discussed in recent years to increase remyelination of affected axons in demyelinating diseases such as multiple sclerosis. These approaches range from pharmacological treatments that reduce inflammatory processes or block ion channels to the modulation of neuronal activity through electrical cortical stimulation. However, these treatments either affect the entire organism (pharmacological) or exert a very local effect (electrodes). Current results show that neuronal activity is a strong regulator of oligodendroglial development. To bridge the gap between global and very local treatments, non-invasive transcranial magnetic stimulation could be considered. Transcranial magnetic stimulation is externally applied to brain areas and experiments with repetitive transcranial magnetic stimulation show that the neuronal activity can be modulated depending on the stimulation parameters in both humans and animals. In this review, we discuss the possibilities of influencing ion channel distribution and increasing neuronal activity by transcranial magnetic stimulation as well as the effect of this modulation on oligodendroglial cells and their capacity to remyelinate previously demyelinated axons. Although the physiological mechanisms underlying the effects of transcranial magnetic stimulation clearly need further investigations, repetitive transcranial magnetic stimulation may be a promising approach for non-invasive neuronal modulation aiming at enhancing remyelination and thus reducing neurodegeneration.
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Affiliation(s)
- Friederike Pfeiffer
- Werner Reichardt Centre for Integrative Neuroscience (CIN), University of Tübingen, Tübingen, Germany
| | - Alia Benali
- Werner Reichardt Centre for Integrative Neuroscience (CIN); Section for Computational Sensomotorics, Department of Cognitive Neurology, Hertie-Institute for Clinical Brain Research and Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
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Clark AR, Hsu CG, Talukder MAH, Noble M, Elfar JC. Transdermal delivery of 4-aminopyridine accelerates motor functional recovery and improves nerve morphology following sciatic nerve crush injury in mice. Neural Regen Res 2020; 15:136-144. [PMID: 31535662 PMCID: PMC6862422 DOI: 10.4103/1673-5374.264471] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Oral 4-aminopyridine (4-AP) is clinically used for symptomatic relief in multiple sclerosis and we recently demonstrated that systemic 4-AP had previously unknown clinically-relevant effects after traumatic peripheral nerve injury including the promotion of re-myelination, improvement of nerve conductivity, and acceleration of functional recovery. We hypothesized that, instead of oral or injection administration, transdermal 4-AP (TD-4-AP) could also improve functional recovery after traumatic peripheral nerve injury. Mice with surgical traumatic peripheral nerve injury received TD-4AP or vehicle alone and were examined for skin permeability, pharmacokinetics, functional, electrophysiological, and nerve morphological properties. 4-AP showed linear pharmacokinetics and the maximum plasma 4-AP concentrations were proportional to TD-4-AP dose. While a single dose of TD-4-AP administration demonstrated rapid transient improvement in motor function, chronic TD-4-AP treatment significantly improved motor function and nerve conduction and these effects were associated with fewer degenerating axons and thicker myelin sheaths than those from vehicle controls. These findings provide direct evidence for the potential transdermal applicability of 4-AP and demonstrate that 4-AP delivered through the skin can enhance in-vivo functional recovery and nerve conduction while decreasing axonal degeneration. The animal experiments were approved by the University Committee on Animal Research (UCAR) at the University of Rochester (UCAR-2009-019) on March 31, 2017.
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Affiliation(s)
- Andrew R Clark
- Department of Orthopaedics, The University of Rochester Medical Center, Rochester, NY, USA
| | - Chia George Hsu
- Department of Medicine, Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - M A Hassan Talukder
- Center for Orthopaedic Research and Translational Science, Penn State Hershey College of Medicine, Milton S. Hershey Medical Center, Hershey, PA, USA
| | - Mark Noble
- Department of Biomedical Genetics, The University of Rochester Medical Center, Rochester, NY, USA
| | - John C Elfar
- Center for Orthopaedic Research and Translational Science, Penn State Hershey College of Medicine, Milton S. Hershey Medical Center, Hershey, PA, USA
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29
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Alves ACDB, Bristot VJDO, Limana MD, Speck AE, Barros LSD, Solano AF, Aguiar AS. Role of Adenosine A 2A Receptors in the Central Fatigue of Neurodegenerative Diseases. J Caffeine Adenosine Res 2019. [DOI: 10.1089/caff.2019.0009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- Ana Cristina de Bem Alves
- Exercise Biology Lab, Department of Health Sciences, UFSC—Universidade Federal de Santa Catarina, Araranguá, Brazil
| | | | - Mirieli Denardi Limana
- Exercise Biology Lab, Department of Health Sciences, UFSC—Universidade Federal de Santa Catarina, Araranguá, Brazil
| | - Ana Elisa Speck
- Exercise Biology Lab, Department of Health Sciences, UFSC—Universidade Federal de Santa Catarina, Araranguá, Brazil
| | - Leonardo Soares de Barros
- LABOX—Laboratório de Bioenergética e Estresse Oxidativo, Departamento de Bioquímica, UFSC—Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - Alexandre Francisco Solano
- LABOX—Laboratório de Bioenergética e Estresse Oxidativo, Departamento de Bioquímica, UFSC—Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - Aderbal S. Aguiar
- Exercise Biology Lab, Department of Health Sciences, UFSC—Universidade Federal de Santa Catarina, Araranguá, Brazil
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Bozic I, Savic D, Milosevic A, Janjic M, Laketa D, Tesovic K, Bjelobaba I, Jakovljevic M, Nedeljkovic N, Pekovic S, Lavrnja I. The Potassium Channel Kv1.5 Expression Alters During Experimental Autoimmune Encephalomyelitis. Neurochem Res 2019; 44:2733-2745. [PMID: 31624998 DOI: 10.1007/s11064-019-02892-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 09/23/2019] [Accepted: 10/11/2019] [Indexed: 12/29/2022]
Abstract
Multiple sclerosis (MS) is a chronic, inflammatory, neurodegenerative disease with an autoimmune component. It was suggested that potassium channels, which are involved in crucial biological functions may have a role in different diseases, including MS and its animal model, experimental autoimmune encephalomyelitis (EAE). It was shown that voltage-gated potassium channels Kv1.5 are responsible for fine-tuning in the immune physiology and influence proliferation and differentiation in microglia and astrocytes. Here, we explored the cellular distribution of the Kv1.5 channel, together with its transcript and protein expression in the male rat spinal cord during different stages of EAE. Our results reveal a decrease of Kv1.5 transcript and protein level at the peak of disease, where massive infiltration of myeloid cells occurs, together with reactive astrogliosis and demyelination. Also, we revealed that the presence of this channel is not found in infiltrating macrophages/microglia during EAE. It is interesting to note that Kv1.5 channel is expressed only in resting microglia in the naïve animals. Predominant expression of Kv1.5 channel was found in the astrocytes in all experimental groups, while some vimentin+ cells, resembling macrophages, are devoid of Kv1.5 expression. Our results point to the possible link between Kv1.5 channel and the pathophysiological processes in EAE.
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Affiliation(s)
- I Bozic
- Department of Neurobiology, Institute for Biological Research "Siniša Stanković"- National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - D Savic
- Department of Neurobiology, Institute for Biological Research "Siniša Stanković"- National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - A Milosevic
- Department of Neurobiology, Institute for Biological Research "Siniša Stanković"- National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - M Janjic
- Department of Neurobiology, Institute for Biological Research "Siniša Stanković"- National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - D Laketa
- Department for General Physiology and Biophysics, Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - K Tesovic
- Department of Neurobiology, Institute for Biological Research "Siniša Stanković"- National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - I Bjelobaba
- Department of Neurobiology, Institute for Biological Research "Siniša Stanković"- National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - M Jakovljevic
- Department of Neurobiology, Institute for Biological Research "Siniša Stanković"- National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - N Nedeljkovic
- Department for General Physiology and Biophysics, Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - S Pekovic
- Department of Neurobiology, Institute for Biological Research "Siniša Stanković"- National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - I Lavrnja
- Department of Neurobiology, Institute for Biological Research "Siniša Stanković"- National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia.
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Modrak M, Talukder MAH, Gurgenashvili K, Noble M, Elfar JC. Peripheral nerve injury and myelination: Potential therapeutic strategies. J Neurosci Res 2019; 98:780-795. [PMID: 31608497 DOI: 10.1002/jnr.24538] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 08/30/2019] [Accepted: 09/16/2019] [Indexed: 12/11/2022]
Abstract
Traumatic peripheral nerve injury represents a major clinical and public health problem that often leads to significant functional impairment and permanent disability. Despite modern diagnostic procedures and advanced microsurgical techniques, functional recovery after peripheral nerve repair is often unsatisfactory. Therefore, there is an unmet need for new therapeutic or adjunctive strategies to promote the functional recovery in nerve injury patients. In contrast to the central nervous system, Schwann cells in the peripheral nervous system play a pivotal role in several aspects of nerve repair such as degeneration, remyelination, and axonal growth. Several non-surgical approaches, including pharmacological, electrical, cell-based, and laser therapies, have been employed to promote myelination and enhance functional recovery after peripheral nerve injury. This review will succinctly discuss the potential therapeutic strategies in the context of myelination following peripheral neurotrauma.
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Affiliation(s)
- Max Modrak
- School of Medicine & Dentistry, The University of Rochester Medical Center, Rochester, New York, USA
| | - M A Hassan Talukder
- Department of Orthopaedics & Rehabilitation, Penn State Hershey College of Medicine, Milton S. Hershey Medical Center, Hershey, Pennsylvania, USA
| | - Khatuna Gurgenashvili
- Department of Neurology, Penn State Hershey College of Medicine, Milton S. Hershey Medical Center, Hershey, Pennsylvania, USA
| | - Mark Noble
- Department of Biomedical Genetics, The University of Rochester Medical Center, Rochester, New York, USA
| | - John C Elfar
- Department of Orthopaedics & Rehabilitation, Penn State Hershey College of Medicine, Milton S. Hershey Medical Center, Hershey, Pennsylvania, USA
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Ishida N, Kondo Y, Chikano Y, Kobayashi‐Nakade E, Suga Y, Ishizaki J, Komai K, Matsushita R. Pharmacokinetics and tissue distribution of 3,4‐diaminopyridine in rats. Biopharm Drug Dispos 2019; 40:294-301. [DOI: 10.1002/bdd.2203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 07/12/2019] [Accepted: 08/09/2019] [Indexed: 11/05/2022]
Affiliation(s)
- Natsuko Ishida
- Faculty of Pharmacy, Institute of Medical, Pharmaceutical and Health SciencesKanazawa University Kakuma‐machi Kanazawa Ishikawa 920‐1192 Japan
- Department of Clinical Research, Iou National HospitalNational Hospital Organization Ishikawa Japan
| | - Yuya Kondo
- Faculty of Pharmacy, Institute of Medical, Pharmaceutical and Health SciencesKanazawa University Kakuma‐machi Kanazawa Ishikawa 920‐1192 Japan
| | - Yuri Chikano
- Faculty of Pharmacy, Institute of Medical, Pharmaceutical and Health SciencesKanazawa University Kakuma‐machi Kanazawa Ishikawa 920‐1192 Japan
| | - Erina Kobayashi‐Nakade
- Faculty of Pharmacy, Institute of Medical, Pharmaceutical and Health SciencesKanazawa University Kakuma‐machi Kanazawa Ishikawa 920‐1192 Japan
| | - Yukio Suga
- Faculty of Pharmacy, Institute of Medical, Pharmaceutical and Health SciencesKanazawa University Kakuma‐machi Kanazawa Ishikawa 920‐1192 Japan
| | - Junko Ishizaki
- Faculty of Pharmacy, Institute of Medical, Pharmaceutical and Health SciencesKanazawa University Kakuma‐machi Kanazawa Ishikawa 920‐1192 Japan
| | - Kiyonobu Komai
- Department of Neurology, Hokuriku Brain and Neuromuscular Disease Center, Iou National HospitalNational Hospital Organization Ishikawa Japan
| | - Ryo Matsushita
- Faculty of Pharmacy, Institute of Medical, Pharmaceutical and Health SciencesKanazawa University Kakuma‐machi Kanazawa Ishikawa 920‐1192 Japan
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Hansen T, Tarasova OS, Khammy MM, Ferreira A, Kennard JA, Andresen J, Staehr C, Brain KL, Nilsson H, Aalkjær C. [Ca 2+ ] changes in sympathetic varicosities and Schwann cells in rat mesenteric arteries-Relation to noradrenaline release and contraction. Acta Physiol (Oxf) 2019; 226:e13279. [PMID: 30957955 DOI: 10.1111/apha.13279] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 03/08/2019] [Accepted: 04/02/2019] [Indexed: 11/29/2022]
Abstract
AIM This study aimed to assess intracellular Ca2+ dynamics in nerve cells and Schwann cells in isolated rat resistance arteries and determine how these dynamics modify noradrenaline release from the nerves and consequent force development. METHODS Ca2+ in nerves was assessed with confocal imaging, noradrenaline release with amperometry and artery tone with wire myography. Ca2+ in axons was assessed after loading with Oregon Green 488 BAPTA-1 dextran. In other experiments, arteries were incubated with Calcium Green-1-AM which loads both axons and Schwann cells. RESULTS Schwann cells but not axons responded with a Ca2+ increase to ATP. Electrical field stimulation of nerves caused a frequency-dependent increase in varicose [Ca2+ ] ([Ca2+ ]v ). ω-conotoxin-GVIA (100 nmol/L) reduced the [Ca2+ ]v transient to 2 and 16 Hz by 60% and 27%, respectively; in contrast ω-conotoxin GVIA inhibited more than 80% of the noradrenaline release and force development at 2 and 16 Hz. The KV channel blocker, 4-aminopyridine (10 µmol/L), increased [Ca2+ ]v , noradrenaline release and force development both in the absence and presence of ω-conotoxin-GVIA. Yohimbine (1 µmol/L) increased both [Ca2+ ]v and noradrenaline release but reduced force development. Acetylcholine (10 µmol/L) caused atropine-sensitive inhibition of [Ca2+ ]v , noradrenaline release and force. In the presence of ω-conotoxin-GVIA, acetylcholine caused a further inhibition of all parameters. CONCLUSION Modification of [Ca2+ ] in arterial sympathetic axons and Schwann cells was assessed separately. KV 3.1 channels may be important regulators of [Ca2+ ]v , noradrenaline release and force development. Presynaptic adrenoceptor and muscarinic receptor activation modify transmitter release through modification of [Ca2+ ]v .
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Affiliation(s)
- Thomas Hansen
- Department of Biomedicine University of Aarhus Aarhus C Denmark
| | - Olga S. Tarasova
- Faculty of Biology M.V. Lomonosov Moscow State University Moscow Russia
- State Research Center of the Russian Federation – Institute for Biomedical Problems Moscow Russia
| | | | | | - James A. Kennard
- Institute of Clinical Sciences, College of Medical and Dental Sciences University of Birmingham Birmingham UK
| | - Jørgen Andresen
- Department of Biomedicine University of Aarhus Aarhus C Denmark
| | | | - Keith L. Brain
- Institute of Clinical Sciences, College of Medical and Dental Sciences University of Birmingham Birmingham UK
| | - Holger Nilsson
- Department of Physiology, Institute of Neuroscience and Physiology Sahlgrenska Academy at the University of Gothenburg Gothenburg Sweden
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Kostadinova I, Danchev N. 4-aminopyridine – the new old drug for the treatment of neurodegenerative diseases. PHARMACIA 2019. [DOI: 10.3897/pharmacia.66.e35976] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In this review are described the preclinical and clinical pharmacological data as well as new therapeutic indications for the use of 4-aminopyridine. 4-aminopyridine is a potassium (K+) channel blocker that has a long history and various application areas. It is a chemical agent developed in 1963 as a bird poison. The first approval for clinical application of 4-aminopyridine was in 70’s in Bulgaria, since anesthetists in that country have confirmed its effect as reversal agent for nondepolarizing myorelaxants. The Bulgarian pharmaceutical company Sopharma commersialized 4-aminopyridine under the trade name Pymadin. Since then 4-aminopyridine was extensively studied and in 2010 is approved in the USA for the treatment of walking disabilities in patients with multiple sclerosis. In recent years, data from clinical trials indicated that K-channel blockade may prove to be an appropriate strategy to overcome disturbances in nerve impulses conduction associated with demyelination of the central nervous system.
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De Giglio L, De Luca F, Gurreri F, Ferrante I, Prosperini L, Borriello G, Quartuccio E, Gasperini C, Pozzilli C. Effect of dalfampridine on information processing speed impairment in multiple sclerosis. Neurology 2019; 93:e733-e746. [DOI: 10.1212/wnl.0000000000007970] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Accepted: 04/30/2019] [Indexed: 02/02/2023] Open
Abstract
ObjectiveTo test a possible benefit of dalfampridine on information processing speed (IPS), a key function for cognitive impairment (CogIm) in multiple sclerosis (MS).MethodsIn this randomized, double-blind, placebo-controlled trial, we included patients with a score on the Symbol Digit Modalities Test (SDMT) under the 10th percentile of the reference value. Patients were randomized in a 2:1 ratio to receive dalfampridine 10 mg or placebo twice daily for 12 weeks. They underwent a comprehensive neuropsychological evaluation at screening (T0), at the end of treatment (T1), and after a 4-week follow-up (T2). The primary endpoint was improvement in SDMT.ResultsOut of 208 patients screened, 120 were randomized to receive either dalfampridine (n = 80) or placebo (n = 40). At T1, the dalfampridine group presented an increase of SDMT scores vs placebo group (mean change 9.9 [95% confidence interval (CI) 8.5–11.4] vs 5.2 [95% CI 2.8–7.6], p = 0.0018; d = 0.60 for raw score; and 0.8 [95% CI 0.6–1] vs 0.3 [95% CI 0.0–0.5], p = 0.0013; d = 0.61 for z scores; by linear mixed model with robust standard error). The improvement was not sustained at T2. A beneficial effect of dalfampridine was observed in the Paced Auditory Serial Addition Test and in cognitive fatigue.ConclusionDalfampridine could be considered as an effective treatment option for IPS impairment in MS.Trial registration2013-002558-64 EU Clinical Trials Register.Classification of evidenceThis study provides Class I evidence that for patients with MS with low scores on the SDMT, dalfampridine improves IPS.
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Manoukian OS, Arul MR, Rudraiah S, Kalajzic I, Kumbar SG. Aligned microchannel polymer-nanotube composites for peripheral nerve regeneration: Small molecule drug delivery. J Control Release 2019; 296:54-67. [PMID: 30658124 PMCID: PMC6379151 DOI: 10.1016/j.jconrel.2019.01.013] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 01/03/2019] [Accepted: 01/14/2019] [Indexed: 12/18/2022]
Abstract
Peripheral nerve injury accounts for roughly 2.8% of all trauma patients with an annual cost of 7 billion USD in the U.S. alone. Current treatment options rely on surgical intervention with the use of an autograft, despite associated shortcomings. Engineered nerve guidance conduits, stem cell therapies, and transient electrical stimulation have reported to increase speeds of functional recovery. As an alternative to the conduction effects of electrical stimulation, we have designed and optimized a nerve guidance conduit with aligned microchannels for the sustained release of a small molecule drug that promotes nerve impulse conduction. A biodegradable chitosan structure reinforced with drug-loaded halloysite nanotubes (HNT) was formed into a foam-like conduit with interconnected, longitudinally-aligned pores with an average pore size of 59.3 ± 14.2 μm. The aligned composite with HNTs produced anisotropic mechanical behavior with a Young's modulus of 0.33 ± 0.1 MPa, very similar to that of native peripheral nerve. This manuscript reports on the sustained delivery of 4-Aminopyridine (4AP, molecular weight 94.1146 g/mol), a potassium-channel blocker as a growth factor alternative to enhance the rate of nerve regeneration. The conduit formulation released a total of 30 ± 2% of the encapsulated 4AP in the first 7 days. Human Schwann cells showed elevated expression of key proteins such as nerve growth factor, myelin protein zero, and brain derived neurotrophic factor in a 4AP dose dependent manner. Preliminary in vivo studies in a critical-sized sciatic nerve defect in Wistar rats confirmed conduit suturability and strength to withstand ambulatory forces over 4 weeks of their implantation. Histological evaluations suggest conduit biocompatibility and Schwann cell infiltration and organization within the conduit and lumen. These nerve guidance conduits and 4AP sustained delivery may serve as an attractive strategy for nerve repair and regeneration.
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Affiliation(s)
- Ohan S Manoukian
- Department of Biomedical Engineering, University of Connecticut, Storrs, CT, USA; Department of Orthopaedic Surgery, University of Connecticut Health, Farmington, CT, USA
| | - Michael R Arul
- Department of Orthopaedic Surgery, University of Connecticut Health, Farmington, CT, USA
| | - Swetha Rudraiah
- Department of Orthopaedic Surgery, University of Connecticut Health, Farmington, CT, USA; Department of Pharmaceutical Sciences, University of Saint Joseph, Hartford, CT, USA
| | - Ivo Kalajzic
- Department of Reconstructive Sciences, University of Connecticut Health, Farmington, CT, USA
| | - Sangamesh G Kumbar
- Department of Biomedical Engineering, University of Connecticut, Storrs, CT, USA; Department of Orthopaedic Surgery, University of Connecticut Health, Farmington, CT, USA.
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Malak OA, Gluhov GS, Grizel AV, Kudryashova KS, Sokolova OS, Loussouarn G. Voltage-dependent activation in EAG channels follows a ligand-receptor rather than a mechanical-lever mechanism. J Biol Chem 2019; 294:6506-6521. [PMID: 30808709 DOI: 10.1074/jbc.ra119.007626] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 02/21/2019] [Indexed: 01/08/2023] Open
Abstract
Ether-a-go-go family (EAG) channels play a major role in many physiological processes in humans, including cardiac repolarization and cell proliferation. Cryo-EM structures of two of them, KV10.1 and human ether-a-go-go-related gene (hERG or KV11.1), have revealed an original nondomain-swapped structure, suggesting that the mechanism of voltage-dependent gating of these two channels is quite different from the classical mechanical-lever model. Molecular aspects of hERG voltage-gating have been extensively studied, indicating that the S4-S5 linker (S4-S5L) acts as a ligand binding to the S6 gate (S6 C-terminal part, S6T) and stabilizes it in a closed state. Moreover, the N-terminal extremity of the channel, called N-Cap, has been suggested to interact with S4-S5L to modulate channel voltage-dependent gating, as N-Cap deletion drastically accelerates hERG channel deactivation. In this study, using COS-7 cells, site-directed mutagenesis, electrophysiological measurements, and immunofluorescence confocal microscopy, we addressed whether these two major mechanisms of voltage-dependent gating are conserved in KV10.2 channels. Using cysteine bridges and S4-S5L-mimicking peptides, we show that the ligand/receptor model is conserved in KV10.2, suggesting that this model is a hallmark of EAG channels. Truncation of the N-Cap domain, Per-Arnt-Sim (PAS) domain, or both in KV10.2 abolished the current and altered channel trafficking to the membrane, unlike for the hERG channel in which N-Cap and PAS domain truncations mainly affected channel deactivation. Our results suggest that EAG channels function via a conserved ligand/receptor model of voltage gating, but that the N-Cap and PAS domains have different roles in these channels.
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Affiliation(s)
- Olfat A Malak
- From the INSERM, CNRS, l'Institut du Thorax, Université de Nantes, 44007 Nantes, France
| | - Grigory S Gluhov
- the Moscow M.V. Lomonosov State University, Moscow 119234, Russia
| | - Anastasia V Grizel
- the Saint Petersburg State University, Saint Petersburg 199034, Russia, and
| | - Kseniya S Kudryashova
- the Moscow M.V. Lomonosov State University, Moscow 119234, Russia.,the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of Russian Academy of Sciences, Moscow 117997, Russia
| | - Olga S Sokolova
- the Moscow M.V. Lomonosov State University, Moscow 119234, Russia
| | - Gildas Loussouarn
- From the INSERM, CNRS, l'Institut du Thorax, Université de Nantes, 44007 Nantes, France,
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Ghebleh Zadeh N, Vaezi G, Bakhtiarian A, Mousavi Z, Shiravi A, Nikoui V. The potassium channel blocker, dalfampridine diminishes ouabain-induced arrhythmia in isolated rat atria. Arch Physiol Biochem 2019; 125:25-29. [PMID: 29390872 DOI: 10.1080/13813455.2018.1430158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The aim of the present experiment was to investigate the possible antiarrhythmic effects of dalfampridine in ouabain-induced arrhythmia in rats. Twenty-four male rats including the control and dalfampridine-incubated (100 µM to 10 mM) ouabain-stimulated (40 µM) groups were used. After induction of anesthesia, the atria were isolated and the time of onset of arrhythmia and asystole were recorded. The contractile force of atria was also measured. Dalfampridine at concentration of 1 mM significantly postponed the onset of arrhythmia and asystole compared to control group (p ≤ .05). Ouabain significantly increased the atrial beating rate in control group (p ≤ .05), while pretreatment of isolated atria with dalfampridine reversed this effect. Incubation of isolated atria with ouabain did not alter the contractile force in both control- and dalfampridine-treated groups (p > .05). It is concluded that dalfampridine might possess antiarrhythmic properties in reducing the atrial arrhythmias.
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Affiliation(s)
- Nahid Ghebleh Zadeh
- a Department of Biology, Damghan Branch , Islamic Azad University , Damghan , Iran
| | - Gholamhassan Vaezi
- a Department of Biology, Damghan Branch , Islamic Azad University , Damghan , Iran
| | - Azam Bakhtiarian
- b Department of Pharmacology, School of Medicine , Tehran University of Medical Sciences , Tehran , Iran
- c Experimental Medicine Research Center , Tehran University of Medical Sciences , Tehran , Iran
| | - Zahra Mousavi
- d Department of Pharmacology-Toxicology, Faculty of Pharmacy, Pharmaceutical Sciences Branch , Islamic Azad University (IAUPS) , Tehran , Iran
| | - Abdolhossein Shiravi
- a Department of Biology, Damghan Branch , Islamic Azad University , Damghan , Iran
| | - Vahid Nikoui
- e Razi Drug Research Center , Iran University of Medical Sciences , Tehran , Iran
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Laws TR, Taylor AW, Russell P, Williamson D. The treatment of melioidosis: is there a role for repurposed drugs? A proposal and review. Expert Rev Anti Infect Ther 2019; 17:957-967. [PMID: 30626237 DOI: 10.1080/14787210.2018.1496330] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Introduction: Melioidosis is a significant health problem within endemic areas such as Southeast Asia and Northern Australia. The varied presentation of melioidosis and the intrinsic antibiotic resistance of Burkholderia pseudomallei, the causative organism, make melioidosis a difficult infection to manage. Often prolonged courses of antibiotic treatments are required with no guarantee of clinical success.Areas covered: B. pseudomallei is able to enter phagocytic cells, affect immune function, and replicate, via manipulation of the caspase system. An examination of this mechanism, and a look at other factors in the pathogenesis of melioidosis, shows that there are multiple potential points of therapeutic intervention, some of which may be complementary. These include the directed use of antimicrobial compounds, blocking virulence mechanisms, balancing or modulating cytokine responses, and ameliorating sepsis.Expert commentary: There may be therapeutic options derived from drugs in clinical use for unrelated conditions that may have benefit in melioidosis. Key compounds of interest primarily affect the disequilibrium of the cytokine response, and further preclinical work is needed to explore the utility of this approach and encourage the clinical research needed to bring these into beneficial use.
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Affiliation(s)
- Thomas R Laws
- CBR Division, DSTL Porton Down, Salisbury, Wiltshire, UK
| | - Adam W Taylor
- CBR Division, DSTL Porton Down, Salisbury, Wiltshire, UK
| | - Paul Russell
- CBR Division, DSTL Porton Down, Salisbury, Wiltshire, UK
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Hobart J, Ziemssen T, Feys P, Linnebank M, Goodman AD, Farrell R, Hupperts R, Blight AR, Englishby V, McNeill M, Chang I, Lima G, Elkins J. Assessment of Clinically Meaningful Improvements in Self-Reported Walking Ability in Participants with Multiple Sclerosis: Results from the Randomized, Double-Blind, Phase III ENHANCE Trial of Prolonged-Release Fampridine. CNS Drugs 2019; 33:61-79. [PMID: 30535670 PMCID: PMC6328522 DOI: 10.1007/s40263-018-0586-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Walking impairment is a hallmark of multiple sclerosis (MS). It affects > 90% of individuals over time, reducing independence and negatively impacting health-related quality of life, productivity, and daily activities. Walking impairment is consistently reported as one of the most distressing impairments by individuals with MS. Prolonged-release (PR)-fampridine previously has been shown to improve objectively measured walking speed in walking-impaired adults with MS. The impact of PR-fampridine from the perspective of the individual with MS warrants full and detailed examination. OBJECTIVE The objective of this study was to evaluate whether PR-fampridine has a clinically meaningful effect on self-reported walking ability in walking-impaired participants with MS. METHODS ENHANCE was a phase III, randomized, double-blind, placebo-controlled study of PR-fampridine 10 mg twice daily in walking-impaired individuals age 18-70 years with either relapsing or progressive forms of MS and an Expanded Disability Status Scale (EDSS) score of 4.0-7.0 at screening. Participants were stratified by EDSS score (≤ 6.0 or 6.5-7.0) at randomization to ensure a balanced level of disability in the treatment groups. The primary endpoint was the proportion of participants with a mean improvement in the 12-item Multiple Sclerosis Walking Scale (MSWS-12) score exceeding the predefined threshold for clinically meaningful improvement (≥ 8 points) over 24 weeks. Secondary endpoints included the proportion with ≥ 15% improvement in Timed Up and Go (TUG) speed, and mean changes in Multiple Sclerosis Impact Scale physical impact subscale (MSIS-29 PHYS), Berg Balance Scale (BBS), and ABILHAND scores over 24 weeks. RESULTS In total, 636 participants with MS were randomized (PR-fampridine, n = 317; placebo, n = 319; modified intention-to-treat sample: PR-fampridine, n = 315; placebo, n = 318). At baseline in the PR-fampridine and placebo groups, 46% and 51% had a progressive form of MS, median [range] EDSS scores were 6.0 [4.0-7.0] and 5.5 [4.0-7.0], mean [range] MSWS-12 scores were 63.6 [0-100] and 65.4 [0-100], and mean [range] TUG speed was 0.38 [0.0-1.0] and 0.38 [0.0-1.2] feet/s, respectively. A significantly higher percentage of PR-fampridine-treated participants (136/315 [43.2%]) had clinically meaningful improvement in MSWS-12 score over 24 weeks versus placebo (107/318 [33.6%]; odds ratio 1.61 [95% confidence interval 1.15-2.26]; p = 0.006). For PR-fampridine versus placebo, significantly more participants had a ≥ 15% improvement in TUG speed, and there was significantly greater mean improvement in MSIS-29 PHYS score (p < 0.05); numerical improvements that were not statistically significant were observed in BBS/ABILHAND. Adverse events that were more common in the PR-fampridine group than placebo group (difference ≥ 3%) by Medical Dictionary for Regulatory Activities (MedDRA®) Preferred Term were urinary tract infection and insomnia. There were no seizures reported. CONCLUSIONS PR-fampridine treatment resulted in sustained, clinically meaningful improvements over 24 weeks in self-reported walking and functional ability in walking-disabled participants with MS. CLINICALTRIALS. GOV IDENTIFIER NCT02219932.
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Affiliation(s)
- Jeremy Hobart
- Plymouth University Peninsula Schools of Medicine and Dentistry, University Hospitals Plymouth NHS Trust, N13 ITTC Building, Plymouth Science Park, Plymouth, Devon, PL6 8BX, UK.
| | - Tjalf Ziemssen
- Center of Clinical Neuroscience, Carl Gustav Carus University Clinic, Technical University of Dresden, Dresden, Germany
| | - Peter Feys
- BIOMED-REVAL, University of Hasselt, Diepenbeek, Belgium
| | - Michael Linnebank
- HELIOS Klinik Hagen-Ambrock, University Witten/Herdecke, Hagen, Germany
| | - Andrew D. Goodman
- School of Medicine and Dentistry, University of Rochester, Rochester, NY USA
| | - Rachel Farrell
- National Hospital for Neurology and Neurosurgery, University College London Hospitals and University College London Institute of Neurology, London, UK
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Mielcarek A, Wiśniewska A, Dołęga A. Unassisted formation of hemiaminal ether from 4-aminopyridine and o-vanillin - experimental and theoretical study. Struct Chem 2018. [DOI: 10.1007/s11224-018-1105-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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42
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Ramió-Torrentà L, Álvarez-Cermeño J, Arroyo R, Casanova-Estruch B, Fernández O, García-Merino J, Hernández M, Izquierdo G, Martínez-Yélamos S, Meca J, Moral E, Olascoaga J, Prieto J, Saiz A. A guide to treating gait impairment with prolonged-release fampridine (Fampyra ® ) in patients with multiple sclerosis. NEUROLOGÍA (ENGLISH EDITION) 2018. [DOI: 10.1016/j.nrleng.2015.11.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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43
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Shenkarev ZO, Karlova MG, Kulbatskii DS, Kirpichnikov MP, Lyukmanova EN, Sokolova OS. Recombinant Production, Reconstruction in Lipid-Protein Nanodiscs, and Electron Microscopy of Full-Length α-Subunit of Human Potassium Channel Kv7.1. BIOCHEMISTRY (MOSCOW) 2018; 83:562-573. [PMID: 29738690 DOI: 10.1134/s0006297918050097] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Voltage-gated potassium channel Kv7.1 plays an important role in the excitability of cardiac muscle. The α-subunit of Kv7.1 (KCNQ1) is the main structural element of this channel. Tetramerization of KCNQ1 in the membrane results in formation of an ion channel, which comprises a pore and four voltage-sensing domains. Mutations in the human KCNQ1 gene are one of the major causes of inherited arrhythmias, long QT syndrome in particular. The construct encoding full-length human KCNQ1 protein was synthesized in this work, and an expression system in the Pichia pastoris yeast cells was developed. The membrane fraction of the yeast cells containing the recombinant protein (rKCNQ1) was solubilized with CHAPS detergent. To better mimic the lipid environment of the channel, lipid-protein nanodiscs were formed using solubilized membrane fraction and MSP2N2 protein. The rKCNQ1/nanodisc and rKCNQ1/CHAPS samples were purified using the Rho1D4 tag introduced at the C-terminus of the protein. Protein samples were examined using transmission electron microscopy with negative staining. In both cases, homogeneous rKCNQ1 samples were observed based on image analysis. Statistical analysis of the images of individual protein particles solubilized in the detergent revealed the presence of a tetrameric structure confirming intact subunit assembly. A three-dimensional channel structure reconstructed at 2.5-nm resolution represents a compact density with diameter of the membrane part of ~9 nm and height ~11 nm. Analysis of the images of rKCNQ1 in nanodiscs revealed additional electron density corresponding to the lipid bilayer fragment and the MSP2N2 protein. These results indicate that the nanodiscs facilitate protein isolation, purification, and stabilization in solution and can be used for further structural studies of human Kv7.1.
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Affiliation(s)
- Z O Shenkarev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.
| | - M G Karlova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.,Lomonosov Moscow State University, Faculty of Biology, Moscow, 119991, Russia
| | - D S Kulbatskii
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.,Lomonosov Moscow State University, Faculty of Biology, Moscow, 119991, Russia
| | - M P Kirpichnikov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.,Lomonosov Moscow State University, Faculty of Biology, Moscow, 119991, Russia
| | - E N Lyukmanova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.,Lomonosov Moscow State University, Faculty of Biology, Moscow, 119991, Russia
| | - O S Sokolova
- Lomonosov Moscow State University, Faculty of Biology, Moscow, 119991, Russia.
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Jacques F, Schembri A, Nativ A, Paquette C, Kalinowski P. Prolonged-Release Fampridine as Adjunct Therapy to Active Motor Training in MS Patients: A Pilot, Double-Blind, Randomized, Placebo-Controlled Study. Mult Scler J Exp Transl Clin 2018; 4:2055217318761168. [PMID: 29552356 PMCID: PMC5846958 DOI: 10.1177/2055217318761168] [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: 07/26/2017] [Revised: 02/02/2018] [Accepted: 02/02/2018] [Indexed: 11/30/2022] Open
Abstract
Background Both prolonged-release fampridine (PRF) and enabling active motor training (EAMT) are beneficial in multiple sclerosis (MS) patients. Their combined effect is, however, understudied. Objective The objective of this paper is to determine if PRF augments the beneficial effect of EAMT in MS patients as opposed to placebo. Method This is a pilot, randomized, placebo-controlled, double-blind 14-week study. Participants were randomly assigned to receive PRF 10 mg BID (n = 21) or placebo (n = 20). All patients underwent EAMT during the first six weeks. Patients were assessed at –4, 0, 6 and 14 weeks. Results Both groups remained stable between –4 to 0 weeks and showed statistically significant improvements for the six-minute walk and the five-times-sit-to-stand test at weeks 6 and 14. The PRF-treated group achieved a greater mean percentage improvement and a higher incidence of responders in all three tasks at both time points. The study was, however, underpowered to reach statistical significance. Conclusion Our results confirm previous studies demonstrating that MS patients, despite significant disability, do benefit from a rehabilitation program. Our study is the first to show a trend suggesting that PRF in MS patients appears to enhance the benefit of EAMT. Further studies are required to confirm this. Clinical trial registration number with Clinicaltrial.gov: NCT02146534
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Vijayakumar A, Arjun P, Sinthiya A, Duraipandiyan V, Al-Dhabi NA. Synthesis, Crystal Structure, and Free Radical Scavenging Activity of 4-Aminopyridinium 3,5-Dinitrobenzoate. CRYSTALLOGR REP+ 2018. [DOI: 10.1134/s1063774517070318] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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46
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Davis SL, Jay O, Wilson TE. Thermoregulatory dysfunction in multiple sclerosis. HANDBOOK OF CLINICAL NEUROLOGY 2018; 157:701-714. [PMID: 30459034 DOI: 10.1016/b978-0-444-64074-1.00042-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Multiple sclerosis (MS) is a progressive neurologic disorder that disrupts axonal myelin in the central nervous system. Demyelination produces alterations in saltatory conduction, slowed conduction velocity, and a predisposition to conduction block. An estimated 60-80% of MS patients experience temporary worsening of clinical signs and neurologic symptoms with heat exposure (Uhthoff's phenomenon). This heat intolerance in MS is related to the detrimental effects of increased temperature on action potential propagation in demyelinated axons, resulting in conduction slowing and/or block. Additionally, MS may produce impaired neural control of autonomic and endocrine functions. Isolating and interpreting mechanisms responsible for autonomic dysfunction due to MS can be difficult as it may involve sensory impairments, altered neural integration within the central nervous system, impaired effector responses, or combinations of all of these factors. MS lesions occur in areas of the brain responsible for the control and regulation of body temperature and thermoregulatory effector responses, resulting in impaired neural control of sudomotor pathways or neural-induced changes in eccrine sweat glands, as evidenced by observations of reduced sweating responses in MS patients. Although not comprehensive, some evidence exists concerning treatments (cooling, precooling, and pharmacologic) for the MS patient to preserve function and decrease symptom worsening during heat stress. This review focuses on four main themes influencing current understanding of thermoregulatory dysfunction in MS: (1) heat intolerance; (2) central regulation of body temperature; (3) thermoregulatory effector responses; and (4) countermeasures to improve or maintain function during thermal stress.
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Affiliation(s)
- Scott L Davis
- Department of Applied Physiology and Wellness, Southern Methodist University, Dallas, TX, United States.
| | - Ollie Jay
- Faculty of Health Sciences, University of Sydney, Sydney, Australia
| | - Thad E Wilson
- Biomedical Sciences, Marian University College of Osteopathic Medicine, Indianapolis, IN, United States
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Hassan S, Ejaz SA, Saeed A, Shehzad M, Ullah Khan S, Lecka J, Sévigny J, Shabir G, Iqbal J. 4-Aminopyridine based amide derivatives as dual inhibitors of tissue non-specific alkaline phosphatase and ecto-5'-nucleotidase with potential anticancer activity. Bioorg Chem 2017; 76:237-248. [PMID: 29197225 DOI: 10.1016/j.bioorg.2017.11.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 11/04/2017] [Accepted: 11/17/2017] [Indexed: 12/19/2022]
Abstract
Ecto-nucleotidase members i.e., ecto-5'-nucleotidase and alkaline phosphatase, hydrolyze extracellular nucleotides and play an important role in purinergic signaling. Their overexpression are implicated in a variety of pathological states, including immunological diseases, bone mineralization, vascular calcification and cancer, and thus they represent an emerging drug targets. In order to design potent and selective inhibitors, new derivatives of 4-aminopyridine have been synthesized (10a-10m) and their structures were established on the basis of spectral data. The effect of nature and position of substituent was interestingly observed and justified on the basis of their detailed structure activity relationships (SARs) against both families of ecto-nucleotidase. Compound 10a displayed significant inhibition (IC50 ± SEM = 0.25 ± 0.05 µM) that was found ≈168 fold more potent as compared to previously reported inhibitor suramin (IC50 ± SEM = 42.1 ± 7.8 µM). This compound exhibited 6 times more selectivity towards h-TNAP over h-e5'NT. The anticancer potential and mechanism were also established using cell viability assay, flow cytometric analysis and nuclear staining. Molecular docking studies were also carried out to gain insight into the binding interaction of potent compounds within the respective enzyme pockets and herring-sperm DNA.
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Affiliation(s)
- Sidra Hassan
- Centre for Advanced Drug Research, COMSATS Institute of Information Technology, 22060 Abbottabad, Pakistan
| | - Syeda Abida Ejaz
- Centre for Advanced Drug Research, COMSATS Institute of Information Technology, 22060 Abbottabad, Pakistan
| | - Aamer Saeed
- Department of Chemistry, Quaid-I-Azam University, 45320 Islamabad, Pakistan.
| | - Muddasar Shehzad
- Department of Chemistry, Quaid-I-Azam University, 45320 Islamabad, Pakistan
| | - Shafi Ullah Khan
- Centre for Advanced Drug Research, COMSATS Institute of Information Technology, 22060 Abbottabad, Pakistan
| | - Joanna Lecka
- Département de microbiologie-infectiologie et d'immunologie, Faculté de Médecine, Université Laval, Québec, QC, Canada; Centre de Recherche du CHU de Québec - Université Laval, Québec, QC, Canada
| | - Jean Sévigny
- Département de microbiologie-infectiologie et d'immunologie, Faculté de Médecine, Université Laval, Québec, QC, Canada; Centre de Recherche du CHU de Québec - Université Laval, Québec, QC, Canada
| | - Ghulam Shabir
- Department of Chemistry, Quaid-I-Azam University, 45320 Islamabad, Pakistan
| | - Jamshed Iqbal
- Centre for Advanced Drug Research, COMSATS Institute of Information Technology, 22060 Abbottabad, Pakistan.
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Jukkola P, Gu Y, Lovett-Racke AE, Gu C. Suppression of Inflammatory Demyelinaton and Axon Degeneration through Inhibiting Kv3 Channels. Front Mol Neurosci 2017; 10:344. [PMID: 29123469 PMCID: PMC5662905 DOI: 10.3389/fnmol.2017.00344] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 10/10/2017] [Indexed: 01/19/2023] Open
Abstract
The development of neuroprotective and repair strategies for treating progressive multiple sclerosis (MS) requires new insights into axonal injury. 4-aminopyridine (4-AP), a blocker of voltage-gated K+ (Kv) channels, is used in symptomatic treatment of progressive MS, but the underlying mechanism remains unclear. Here we report that deleting Kv3.1—the channel with the highest 4-AP sensitivity—reduces clinical signs in experimental autoimmune encephalomyelitis (EAE), a mouse model for MS. In Kv3.1 knockout (KO) mice, EAE lesions in sensory and motor tracts of spinal cord were markedly reduced, and radial astroglia were activated with increased expression of brain derived neurotrophic factor (BDNF). Kv3.3/Kv3.1 and activated BDNF receptors were upregulated in demyelinating axons in EAE and MS lesions. In spinal cord myelin coculture, BDNF treatment promoted myelination, and neuronal firing via altering channel expression. Therefore, suppressing Kv3.1 alters neural circuit activity, which may enhance BNDF signaling and hence protect axons from inflammatory insults.
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Affiliation(s)
- Peter Jukkola
- Biomedical Sciences Graduate Program, Wexner Medical Center, The Ohio State University, Columbus, OH, United States
| | - Yuanzheng Gu
- Department of Biological Chemistry and Pharmacology, Wexner Medical Center, The Ohio State University, Columbus, OH, United States
| | - Amy E Lovett-Racke
- Department of Microbial Infection and Immunity, Wexner Medical Center, The Ohio State University, Columbus, OH, United States
| | - Chen Gu
- Biomedical Sciences Graduate Program, Wexner Medical Center, The Ohio State University, Columbus, OH, United States.,Department of Biological Chemistry and Pharmacology, Wexner Medical Center, The Ohio State University, Columbus, OH, United States
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Arpin DJ, Gehringer JE, Wilson TW, Kurz MJ. A reduced somatosensory gating response in individuals with multiple sclerosis is related to walking impairment. J Neurophysiol 2017; 118:2052-2058. [PMID: 28724780 DOI: 10.1152/jn.00260.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 06/26/2017] [Accepted: 07/17/2017] [Indexed: 12/17/2022] Open
Abstract
When identical stimuli are presented in rapid temporal succession, neural responses to the second stimulation are often weaker than those observed for the first. This phenomenon is termed sensory gating and is believed to be an adaptive feature that helps prevent higher-order cortical centers from being flooded with unnecessary information. Recently, sensory gating in the somatosensory system has been linked to deficits in tactile discrimination. Additionally, studies have linked poor tactile discrimination with impaired walking and balance in individuals with multiple sclerosis (MS). In this study, we examine the neural basis of somatosensory gating in patients with MS and healthy controls and assess the relationship between somatosensory gating and walking performance. We used magnetoencephalography to record neural responses to paired-pulse electrical stimulation applied to the right posterior tibial nerve. All participants also walked across a digital mat, which recorded their spatiotemporal gait kinematics. Our results showed the amplitude of the response to the second stimulation was sharply reduced only in controls, resulting in a significantly reduced somatosensory gating in the patients with MS. No group differences were observed in the amplitude of the response to the first stimulation nor the latency of the neural response to either the first or second stimulation. Interestingly, the altered somatosensory gating responses were correlated with aberrant spatiotemporal gait kinematics in the patients with MS. These results suggest that inhibitory GABA circuits may be altered in patients with MS, which impacts somatosensory gating and contributes to the motor performance deficits seen in these patients.NEW & NOTEWORTHY We aimed to determine whether somatosensory gating in patients with multiple sclerosis (MS) differed compared with healthy controls and whether a relationship exists between somatosensory gating and walking performance. We found reduced somatosensory gating responses in patients with MS, and these altered somatosensory gating responses were correlated with the mobility impairments. These novel findings show that somatosensory gating is impaired in patients with MS and is related to the mobility impairments seen in these patients.
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Affiliation(s)
- David J Arpin
- Department of Physical Therapy, Munroe-Meyer Institute, University of Nebraska Medical Center, Omaha, Nebraska.,Center for Magnetoencephalography, University of Nebraska Medical Center, Omaha, Nebraska; and
| | - James E Gehringer
- Department of Physical Therapy, Munroe-Meyer Institute, University of Nebraska Medical Center, Omaha, Nebraska.,Center for Magnetoencephalography, University of Nebraska Medical Center, Omaha, Nebraska; and
| | - Tony W Wilson
- Center for Magnetoencephalography, University of Nebraska Medical Center, Omaha, Nebraska; and.,Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, Nebraska
| | - Max J Kurz
- Department of Physical Therapy, Munroe-Meyer Institute, University of Nebraska Medical Center, Omaha, Nebraska; .,Center for Magnetoencephalography, University of Nebraska Medical Center, Omaha, Nebraska; and
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Al-Sabi A, Daly D, Hoefer P, Kinsella GK, Metais C, Pickering M, Herron C, Kaza SK, Nolan K, Dolly JO. A Rational Design of a Selective Inhibitor for Kv1.1 Channels Prevalent in Demyelinated Nerves That Improves Their Impaired Axonal Conduction. J Med Chem 2017; 60:2245-2256. [PMID: 28225274 DOI: 10.1021/acs.jmedchem.6b01262] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
K+ channels containing Kv1.1 α subunits, which become prevalent at internodes in demyelinated axons, may underlie their dysfunctional conduction akin to muscle weakness in multiple sclerosis. Small inhibitors were sought with selectivity for the culpable hyper-polarizing K+ currents. Modeling of interactions with the extracellular pore in a Kv1.1-deduced structure identified diaryldi(2-pyrrolyl)methane as a suitable scaffold with optimized alkyl ammonium side chains. The resultant synthesized candidate [2,2'-((5,5'(di-p-topyldiaryldi(2-pyrrolyl)methane)bis(2,2'carbonyl)bis(azanediyl)) diethaneamine·2HCl] (8) selectively blocked Kv1.1 channels (IC50 ≈ 15 μM) recombinantly expressed in mammalian cells, induced a positive shift in the voltage dependency of K+ current activation, and slowed its kinetics. It preferentially inhibited channels containing two or more Kv1.1 subunits regardless of their positioning in concatenated tetramers. In slices of corpus callosum from mice subjected to a demyelination protocol, this novel inhibitor improved neuronal conduction, highlighting its potential for alleviating symptoms in multiple sclerosis.
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Affiliation(s)
| | | | | | - Gemma K Kinsella
- School of Food Science and Environmental Health, College of Sciences and Health, Dublin Institute of Technology , Cathal Brugha Street, Dublin 1, Ireland
| | | | - Mark Pickering
- UCD School of Medicine, University College Dublin , Dublin, Ireland
| | - Caroline Herron
- School of Biomolecular and Biomed Science, Conway Institute , Belfield, Dublin 4, Ireland
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