1
|
Bloms-Funke P, Schumacher M, Liu S, Su D, Li J, Liere P, Rupprecht R, Nothdurfter C, Bahrenberg G, Christoph T, Habermann C, Kneip C, Schröder W, Tzschentke TM, Saunders D. A novel dual mode-of-action anti-hyperalgesic compound in rats which is neuroprotective and promotes neuroregeneration. Eur J Pharmacol 2022; 923:174935. [PMID: 35378102 DOI: 10.1016/j.ejphar.2022.174935] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 03/20/2022] [Accepted: 03/30/2022] [Indexed: 12/25/2022]
Abstract
Chronic neuropathic pain (CNP) can result from surgery or traumatic injury, but also from peripheral neuropathies caused by diseases, viral infections, or toxic treatments. Opioids, although very effective for acute pain, do not prevent the development of CNP, and are considered as insufficient treatment. Therefore, there is high need for effective and safe non-opioid options to treat, prevent and eventually reverse CNP. A more effective approach to alleviating CNP would constitute a treatment that acts concurrently on various mechanisms involved in relieving pain symptoms and preventing or reversing chronification by enhancing both neuroprotection and neuroregeneration. We have identified and characterized GRT-X (N-[(3-fluorophenyl)-methyl]-1-(2-methoxyethyl)-4-methyl-2-oxo-(7-trifluoromethyl)-1H-quinoline-3-caboxylic acid amide), a novel drug which is able to activate both voltage-gated potassium channels of the Kv7 family and the mitochondrial translocator protein 18 kDa (TSPO). The dual mode-of-action (MoA) of GRT-X was indicated in in vitro studies and in vivo in a rat model of diabetic neuropathy. In this model, mechanical hyperalgesia was dose-dependently inhibited. After severe crush lesion of cervical spinal nerves in rats, GRT-X promoted survival, speeded up regrowth of sensory and motor neurons, and accelerated recovery of behavioral and neuronal responses to heat, cold, mechanical and electrical stimuli. These properties may reduce the likelihood of chronification of acute pain, and even potentially relieve established CNP. The absence of a conditioned place preference in rats suggests lack of abuse potential. In conclusion, GRT-X offers a promising preclinical profile with a novel dual MoA.
Collapse
Affiliation(s)
- Petra Bloms-Funke
- Global Preclinical R&D, Grünenthal Innovation, Grünenthal GmbH, Zieglerstraße 6, D-52078, Aachen, Germany.
| | - Michael Schumacher
- U1195 Inserm and University Paris-Saclay, 80, rue du Général Leclerc, 94276, Kremlin-Bicêtre, France
| | - Song Liu
- U1195 Inserm and University Paris-Saclay, 80, rue du Général Leclerc, 94276, Kremlin-Bicêtre, France
| | - Diya Su
- U1195 Inserm and University Paris-Saclay, 80, rue du Général Leclerc, 94276, Kremlin-Bicêtre, France
| | - Jing Li
- U1195 Inserm and University Paris-Saclay, 80, rue du Général Leclerc, 94276, Kremlin-Bicêtre, France
| | - Philippe Liere
- U1195 Inserm and University Paris-Saclay, 80, rue du Général Leclerc, 94276, Kremlin-Bicêtre, France
| | - Rainer Rupprecht
- Department of Psychiatry and Psychotherapy, University Regensburg, Universitätsstraße 84, D-93053, Regensburg, Germany
| | - Caroline Nothdurfter
- Department of Psychiatry and Psychotherapy, University Regensburg, Universitätsstraße 84, D-93053, Regensburg, Germany
| | - Gregor Bahrenberg
- Global Preclinical R&D, Grünenthal Innovation, Grünenthal GmbH, Zieglerstraße 6, D-52078, Aachen, Germany
| | - Thomas Christoph
- Global Preclinical R&D, Grünenthal Innovation, Grünenthal GmbH, Zieglerstraße 6, D-52078, Aachen, Germany
| | - Christopher Habermann
- Global Preclinical R&D, Grünenthal Innovation, Grünenthal GmbH, Zieglerstraße 6, D-52078, Aachen, Germany
| | - Christa Kneip
- Global Preclinical R&D, Grünenthal Innovation, Grünenthal GmbH, Zieglerstraße 6, D-52078, Aachen, Germany
| | - Wolfgang Schröder
- Global Preclinical R&D, Grünenthal Innovation, Grünenthal GmbH, Zieglerstraße 6, D-52078, Aachen, Germany
| | - Thomas M Tzschentke
- Global Preclinical R&D, Grünenthal Innovation, Grünenthal GmbH, Zieglerstraße 6, D-52078, Aachen, Germany
| | - Derek Saunders
- Global Preclinical R&D, Grünenthal Innovation, Grünenthal GmbH, Zieglerstraße 6, D-52078, Aachen, Germany
| |
Collapse
|
2
|
Kir Channel Molecular Physiology, Pharmacology, and Therapeutic Implications. Handb Exp Pharmacol 2021; 267:277-356. [PMID: 34345939 DOI: 10.1007/164_2021_501] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
For the past two decades several scholarly reviews have appeared on the inwardly rectifying potassium (Kir) channels. We would like to highlight two efforts in particular, which have provided comprehensive reviews of the literature up to 2010 (Hibino et al., Physiol Rev 90(1):291-366, 2010; Stanfield et al., Rev Physiol Biochem Pharmacol 145:47-179, 2002). In the past decade, great insights into the 3-D atomic resolution structures of Kir channels have begun to provide the molecular basis for their functional properties. More recently, computational studies are beginning to close the time domain gap between in silico dynamic and patch-clamp functional studies. The pharmacology of these channels has also been expanding and the dynamic structural studies provide hope that we are heading toward successful structure-based drug design for this family of K+ channels. In the present review we focus on placing the physiology and pharmacology of this K+ channel family in the context of atomic resolution structures and in providing a glimpse of the promising future of therapeutic opportunities.
Collapse
|
3
|
Failed, Interrupted, or Inconclusive Trials on Neuroprotective and Neuroregenerative Treatment Strategies in Multiple Sclerosis: Update 2015-2020. Drugs 2021; 81:1031-1063. [PMID: 34086251 PMCID: PMC8217012 DOI: 10.1007/s40265-021-01526-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/15/2021] [Indexed: 02/06/2023]
Abstract
In the recent past, a plethora of drugs have been approved for the treatment of multiple sclerosis (MS). These therapeutics are mainly confined to immunomodulatory or immunosuppressive strategies but do not sufficiently address remyelination and neuroprotection. However, several neuroregenerative agents have shown potential in pre-clinical research and entered Phase I to III clinical trials. Although none of these compounds have yet proceeded to approval, understanding the causes of failure can broaden our knowledge about neuroprotection and neuroregeneration in MS. Moreover, most of the investigated approaches are characterised by consistent mechanisms of action and proved convincing efficacy in animal studies. Therefore, learning from their failure will help us to enforce the translation of findings acquired in pre-clinical studies into clinical application. Here, we summarise trials on MS treatment published since 2015 that have either failed or were interrupted due to a lack of efficacy, adverse events, or for other reasons. We further outline the rationale underlying these drugs and analyse the background of failure to gather new insights into MS pathophysiology and optimise future study designs. For conciseness, this review focuses on agents promoting remyelination and medications with primarily neuroprotective properties or unconventional approaches. Failed clinical trials that pursue immunomodulation are presented in a separate article.
Collapse
|
4
|
Dörr J, Wernecke KD, Würfel J, Bellmann-Strobl J, Siffrin V, Sättler MB, Simons M, Linsa A, Tumani H, Paul F. Disease Modification in Multiple Sclerosis by Flupirtine-Results of a Randomized Placebo Controlled Phase II Trial. Front Neurol 2018; 9:842. [PMID: 30356868 PMCID: PMC6190842 DOI: 10.3389/fneur.2018.00842] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 09/19/2018] [Indexed: 12/31/2022] Open
Abstract
Central nervous system inflammation and neurodegeneration are the pathophysiological hallmarks of multiple sclerosis (MS). While inflammation can readily be targeted by current disease modifying drugs, neurodegeneration is by far less accessible to treatment. Based on suggested additional neuroprotective capacities of the orally available non-opioid and centrally acting analgesic drug flupirtine maleate we hypothesized that treatment with flupirtine maleate might be beneficial in MS patients. The flupirtine as oral treatment in multiple sclerosis (FLORIMS) study was a multi-center, randomized and stratified, placebo-controlled double-blind phase II trial to investigate safety and efficacy in terms of clinical and radiographical activity of flupirtine maleate (300 mg per day) given orally for 12 months, add-on to interferon beta 1b subcutaneously in patients with relapsing remitting MS. Due to a substantial delay in recruitment, enrolment of patients was prematurely terminated after randomization of only 30 of the originally planned 80 patients. Of these, 24 regularly terminated study after 12 months of treatment. Data were analyzed as originally planned. Treatment with flupirtine maleate was overall well tolerated. We observed moderate and asymptomatic elevations of liver enzymes in several cases but no overt hepatotoxicity. Neither the intention to treat nor the per protocol analysis revealed any significant treatment effects of flupirtine maleate with respect to occurrence of MS relapses, disability progression, or development of new lesions on cranial MRI. However, substantial methodological limitations need to be considered when interpreting these results. In conclusion, the results of the FLORIMS study neither add further evidence to nor argue against the hypothesized neuroprotective or disease modifying effects of flupirtine maleate in MS.
Collapse
Affiliation(s)
- Jan Dörr
- NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
| | | | - Jens Würfel
- NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany.,MIAC AG, Department Biomedical Engineering, University Basel, Basel, Switzerland
| | - Judith Bellmann-Strobl
- NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany.,Experimental and Clinical Research Center, Max Delbrueck Center for Molecular Medicine and Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
| | - Volker Siffrin
- Experimental and Clinical Research Center, Max Delbrueck Center for Molecular Medicine and Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
| | | | - Mikael Simons
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany.,German Center for Neurodegenerative Disease (DZNE), Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Andreas Linsa
- Klinik für Neurologie, Carl-Thiem Klinikum Cottbus gGmbH, Cottbus, Germany.,Klinik für Neurologie, Lausitzer Seenland Klinikum GmbH, Hoyerswerda, Germany
| | - Hayrettin Tumani
- Neurologische Uniklinik Ulm im RKU, Ulm, Germany.,Fachklinik für Neurologie Dietenbronn, Schwendi, Germany
| | - Friedemann Paul
- NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany.,Experimental and Clinical Research Center, Max Delbrueck Center for Molecular Medicine and Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany.,Department of Neurology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
| |
Collapse
|
5
|
Liu Y, Huo H, Zhao Z, Hu W, Sun Y, Tang Y. Bioequivalence study of two formulations of flupirtine maleate capsules in healthy male Chinese volunteers under fasting and fed conditions. DRUG DESIGN DEVELOPMENT AND THERAPY 2017; 11:3441-3448. [PMID: 29238169 PMCID: PMC5716300 DOI: 10.2147/dddt.s149913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Aim This study developed a high-performance liquid chromatography–tandem mass spectrometry method to simultaneously determine the concentrations of flupirtine and its major active metabolite D-13223 in human plasma in order to assess the bioequivalence (BE) of two flupirtine maleate capsules among healthy male Chinese volunteers under fasting and fed conditions. Materials and methods There were two single-center, randomized, single-dose, open-label, laboratory-blinded, two-period, cross-over studies which included 24 healthy male Chinese volunteers under fasting and fed conditions, respectively. Plasma samples were collected prior to and up to 48 h after dosing. The concentrations of flupirtine and its major active metabolite D-13223 in plasma samples were determined by a validated method, that is, high-performance liquid chromatography coupled with a tandem mass spectrometry detector. Pharmacokinetic metrics of area from time zero to the last measurable concentration (AUC0−t), area under the plasma concentration–time curve from administration to infinite time (AUC0−∞), and Cmax were used for BE assessment. Results Forty-eight healthy volunteers who met the criteria were enrolled and completed the study. According to the observation of vital signs and laboratory measurement, no volunteers had any adverse reactions. Under fasting condition, the geometric mean ratios (90% CI) of the test/reference drug for flupirtine were 103.0% (98.1%–108.2%) for AUC0−t, 102.9% (98.2%–107.9%) for AUC0−∞, and 97.0% (85.9%–109.5%) for Cmax. Under fed condition, the geometric mean ratios (90% CI) of the test/reference drug for flupirtine were 101.7% (98.4%–105.1%) for AUC0−t, 101.6% (98.5%–104.8%) for AUC0−∞, and 103.5% (94.7%–113.0%) for Cmax. The difference between test and reference formulations, Tmax, was not statistically significant. The 90% CIs of the test/reference AUC ratio and Cmax ratio of D-13223 were also within the acceptance range for BE both under fasting and fed conditions. Conclusion The two formulations of flupirtine maleate capsule were bioequivalent (the test and the reference products) under fasting and fed conditions, and thus both can be used interchangeably in the clinical setting.
Collapse
Affiliation(s)
- Yanfang Liu
- Technical Center for Clinical Pharmacy, Department of Drug Clinical Trail Management Agency, General Hospital of Shenyang Military Area Command, Shenyang, China
| | - Hua Huo
- Technical Center for Clinical Pharmacy, Department of Drug Clinical Trail Management Agency, General Hospital of Shenyang Military Area Command, Shenyang, China
| | - Zhibo Zhao
- Technical Center for Clinical Pharmacy, Department of Drug Clinical Trail Management Agency, General Hospital of Shenyang Military Area Command, Shenyang, China
| | - Wenli Hu
- Technical Center for Clinical Pharmacy, Department of Drug Clinical Trail Management Agency, General Hospital of Shenyang Military Area Command, Shenyang, China
| | - Yujia Sun
- Technical Center for Clinical Pharmacy, Department of Drug Clinical Trail Management Agency, General Hospital of Shenyang Military Area Command, Shenyang, China
| | - Yunbiao Tang
- Technical Center for Clinical Pharmacy, Department of Drug Clinical Trail Management Agency, General Hospital of Shenyang Military Area Command, Shenyang, China
| |
Collapse
|
6
|
Sampath D, Valdez R, White AM, Raol YH. Anticonvulsant effect of flupirtine in an animal model of neonatal hypoxic-ischemic encephalopathy. Neuropharmacology 2017; 123:126-135. [PMID: 28587899 DOI: 10.1016/j.neuropharm.2017.06.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Revised: 05/07/2017] [Accepted: 06/02/2017] [Indexed: 12/20/2022]
Abstract
Research studies suggest that neonatal seizures, which are most commonly associated with hypoxic-ischemic injury, may contribute to brain injury and adverse neurologic outcome. Unfortunately, neonatal seizures are often resistant to treatment with current anticonvulsants. In the present study, we evaluated the efficacy of flupirtine, administered at clinically relevant time-points, for the treatment of neonatal seizures in an animal model of hypoxic-ischemic injury that closely replicates features of the human syndrome. We also compared the efficacy of flupirtine to that of phenobarbital, the current first-line drug for neonatal seizures. Flupirtine is a KCNQ potassium channel opener. KCNQ channels play an important role in controlling brain excitability during early development. In this study, hypoxic-ischemic injury was induced in neonatal rats, and synchronized video-EEG records were acquired at various time-points during the experiment to identify seizures. The results revealed that flupirtine, administered either 5 min after the first electroclinical seizure, or following completion of 2 h of hypoxia, i.e., during the immediate reperfusion period, reduced the number of rats with electroclinical seizures, and also the frequency and total duration of electroclinical seizures. Further, daily dosing of flupirtine decreased the seizure burden over 3 days following HI-induction, and modified the natural evolution of acute seizures. Moreover, compared to a therapeutic dose of phenobarbital, which was modestly effective against electroclinical seizures, flupirtine showed greater efficacy. Our results indicate that flupirtine is an extremely effective treatment for neonatal seizures in rats and provide evidence for a trial of this medication in newborn humans.
Collapse
Affiliation(s)
- Dayalan Sampath
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Robert Valdez
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Andrew M White
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Yogendra H Raol
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, USA.
| |
Collapse
|
7
|
Jaeger HM, Pehlke JR, Kaltwasser B, Kilic E, Bähr M, Hermann DM, Doeppner TR. The indirect NMDAR inhibitor flupirtine induces sustained post-ischemic recovery, neuroprotection and angioneurogenesis. Oncotarget 2016; 6:14033-44. [PMID: 26050199 PMCID: PMC4546449 DOI: 10.18632/oncotarget.4226] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 05/13/2015] [Indexed: 12/20/2022] Open
Abstract
N-methyl-D-aspartate receptor (NMDAR) activation induces excitotoxicity, contributing to post-stroke brain injury. Hitherto, NMDAR deactivation failed in clinical trials due to insufficient pre-clinical study designs and drug toxicity. Flupirtine is an indirect NMDAR antagonist being used as analgesic in patients. Taking into account its tolerability profile, we evaluated effects of flupirtine on post-stroke tissue survival, neurological recovery and brain remodeling. Mice were exposed to stroke and intraperitoneally treated with saline (control) or flupirtine at various doses (1-10 mg/kg) and time-points (0-12 hours). Tissue survival and cell signaling were studied on day 2, whereas neurological recovery and tissue remodeling were analyzed until day 84. Flupirtine induced sustained neuroprotection, when delivered up to 9 hours. The latter yielded enhanced neurological recovery that persisted over three months and which was accompanied by enhanced angioneurogenesis. On the molecular level, inhibition of calpain activation was noted, which was associated with increased signal-transducer-and-activator-of-transcription-6 (STAT6) abundance, reduced N-terminal-Jun-kinase and NF-κB activation, as well as reduced proteasomal activity. Consequently, blood-brain-barrier integrity was stabilized, oxidative stress was reduced and brain leukocyte infiltration was diminished. In view of its excellent tolerability, considering its sustained effects on neurological recovery, brain tissue survival and remodeling, flupirtine is an attractive candidate for stroke therapy.
Collapse
Affiliation(s)
- Hanna M Jaeger
- University of Duisburg-Essen Medical School, Department of Neurology, Essen, Germany
| | - Jens R Pehlke
- LWL-Klinik Muenster, Department of Addiction Disorders, Muenster, Germany
| | - Britta Kaltwasser
- University of Duisburg-Essen Medical School, Department of Neurology, Essen, Germany
| | - Ertugrul Kilic
- Istanbul Medipol University, Regenerative and Restorative Medical Research Center, Istanbul, Turkey
| | - Mathias Bähr
- University of Goettingen Medical School, Department of Neurology, Goettingen, Germany
| | - Dirk M Hermann
- University of Duisburg-Essen Medical School, Department of Neurology, Essen, Germany
| | - Thorsten R Doeppner
- University of Duisburg-Essen Medical School, Department of Neurology, Essen, Germany.,Istanbul Medipol University, Regenerative and Restorative Medical Research Center, Istanbul, Turkey
| |
Collapse
|
8
|
Siegmund W, Modess C, Scheuch E, Methling K, Keiser M, Nassif A, Rosskopf D, Bednarski PJ, Borlak J, Terhaag B. Metabolic activation and analgesic effect of flupirtine in healthy subjects, influence of the polymorphic NAT2, UGT1A1 and GSTP1. Br J Clin Pharmacol 2015; 79:501-13. [PMID: 25264565 DOI: 10.1111/bcp.12522] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 09/20/2014] [Indexed: 12/19/2022] Open
Abstract
AIMS The rare association of flupirtine with liver injury is most likely caused by reactive quinone diimines and their oxidative formation may be influenced by the activities of N-acetyltransferases (NAT) that conjugate the less toxic metabolite D13223, and by glucuronosyltransferases (UGT) and glutathione S-transferases (GST) that generate stable terminal glucuronides and mercapturic acid derivatives, respectively. The influence of genetic polymorphisms of NAT2, UGT1A1 and GSTP1 on generation of the terminal mercapturic acid derivatives and analgesic effects was evaluated to identify potential genetic risk factors for hepatotoxicity of flupirtine. METHODS Metabolic disposition of flupirtine was measured after intravenous administration (100 mg), after swallowing an immediate-release (IR) tablet (100 mg) and after repeated administration of modified release (MR) tablets (400 mg once daily 8 days) in 36 selected healthy subjects. Analgesic effects were measured using pain models (delayed onset of muscle soreness, electric pain). RESULTS Flupirtine IR was rapidly but incompletely absorbed (∼ 72%). Repeated administration of flupirtine MR showed lower bioavailability (∼ 60%). Approximately 12% of bioavailable flupirtine IR and 8% of bioavailable flupiritine MR was eliminated as mercapturic acid derivatives into the urine independent of the UGT1A1, NAT2 and GSTP1 genotype. Carriers of variant GSTP1 alleles showed lower bioavailability but increased intestinal secretion of flupirtine and increased efficiency in experimental pain. Flupirtine was not a substrate for ABCB1 and ABCC2. CONCLUSIONS Formation of mercapturic acid derivatives is a major elimination route for flupirtine in man. However, the theoretically toxic pathway is not influenced by the frequent polymorphisms of UGT1A1, NAT2 and GSTP1.
Collapse
Affiliation(s)
- Werner Siegmund
- Department of Clinical Pharmacology, University Medicine Greifswald, Greifswald, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Liu Y, You C, Zhang Z, Zhang J, Yan H. Roles of Treg/Th17 Cell Imbalance and Neuronal Damage in the Visual Dysfunction Observed in Experimental Autoimmune Optic Neuritis Chronologically. Neuromolecular Med 2015; 17:391-403. [DOI: 10.1007/s12017-015-8368-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 08/22/2015] [Indexed: 12/28/2022]
|
10
|
Chua B, Goldberg I. Neuroprotective agents in glaucoma therapy: recent developments and future directions. EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/eop.10.55] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
|
11
|
Panchanathan E, Ramanathan G, Lakkakula BVKS. Effect of flupirtine on the growth and viability of U373 malignant glioma cells. Cancer Biol Med 2013; 10:142-7. [PMID: 24379989 PMCID: PMC3860341 DOI: 10.7497/j.issn.2095-3941.2013.03.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Accepted: 09/14/2013] [Indexed: 11/23/2022] Open
Abstract
Objective Flupirtine is a non-opioid analgesic without antipyretic or antiphlogistic properties but with favorable tolerability in humans. This analgesic also exhibits neuroprotective activities. Furthermore, flupirtine antagonizes glutamate- and NMDA-induced intracellular levels of Ca2+ and counteracts the effects of focal cerebral ischemia. Although flupirtine has been used to relieve pain caused by different diseases and clinical procedures, information on the safety and efficacy of flupirtine is limited. The present study was conducted to investigate the neuroprotective effects of flupirtine on U373 malignant glioma (MG) cell lines. Methods Cell viability and cell cycle analysis was performed by MTT assay and flow cytometry, respectively. Results Variations in the growth of U373 MG cells in 5 mM N-methyl-D-aspartate (NMDA), 1 mM flupirtine, and combined treatment indicated the antagonistic effects of NMDA and flupirtine on MG cell lines. The variation in the percentage of gated cell population in different cell cycle phases showed significant variations after 48 h of treatment. Conclusion Flupirtine has neuroprotective effect of on U373 MG cells, which limits its use in the pain management of brain tumors. This property warrants further studies using animal models and large-scale clinical trials.
Collapse
Affiliation(s)
- Elango Panchanathan
- Department of Pharmacology, Sri Ramachandra University, Chennai 600118, India
| | | | | |
Collapse
|
12
|
Zhong YS, Wang J, Liu WM, Zhu YH. Potassium ion channels in retinal ganglion cells (review). Mol Med Rep 2013; 8:311-9. [PMID: 23732984 DOI: 10.3892/mmr.2013.1508] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Accepted: 05/22/2013] [Indexed: 11/06/2022] Open
Abstract
Retinal ganglion cells (RGCs) consolidate visual processing and constitute the last step prior to the transmission of signals to higher brain centers. RGC death is a major cause of visual impairment in optic neuropathies, including glaucoma, age‑related macular degeneration, diabetic retinopathy, uveoretinitis and vitreoretinopathy. Discharge patterns of RGCs are primarily determined by the presence of ion channels. As the most diverse group of ion channels, potassium (K+) channels play key roles in modulating the electrical properties of RGCs. Biochemical, molecular and pharmacological studies have identified a number of K+ channels in RGCs, including inwardly rectifying K+ (Kir), ATP‑sensitive K+ (KATP), tandem‑pore domain K+ (TASK), voltage‑gated K+ (Kv), ether‑à‑go‑go (Eag) and Ca2+‑activated K+ (KCa) channels. Kir channels are important in the maintenance of the resting membrane potential and controlling RGC excitability. KATP channels are involved in RGC survival and neuroprotection. TASK channels are hypothesized to contribute to the regulation of resting membrane potentials and firing patterns of RGCs. Kv channels are important regulators of cellular excitability, functioning to modulate the amplitude, duration and frequency of action potentials and subthreshold depolarizations, and are also important in RGC development and protection. Eag channels may contribute to dendritic repolarization during excitatory postsynaptic potentials and to the attenuation of the back propagation of action potentials. KCa channels have been observed to contribute to repetitive firing in RGCs. Considering these important roles of K+ channels in RGCs, the study of K+ channels may be beneficial in elucidating the pathophysiology of RGCs and exploring novel RGC protection strategies.
Collapse
Affiliation(s)
- Yi-Sheng Zhong
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, Shanghai 200025, P.R. China
| | | | | | | |
Collapse
|
13
|
Luessi F, Siffrin V, Zipp F. Neurodegeneration in multiple sclerosis: novel treatment strategies. Expert Rev Neurother 2013; 12:1061-76; quiz 1077. [PMID: 23039386 DOI: 10.1586/ern.12.59] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
In recent years it has become clear that the neuronal compartment already plays an important role early in the pathology of multiple sclerosis (MS). Neuronal injury in the course of chronic neuroinflammation is a key factor in determining long-term disability in patients. Viewing MS as both inflammatory and neurodegenerative has major implications for therapy, with CNS protection and repair needed in addition to controlling inflammation. Here, the authors' review recently elucidated molecular insights into inflammatory neuronal/axonal pathology in MS and discuss the resulting options regarding neuroprotective and regenerative treatment strategies.
Collapse
Affiliation(s)
- Felix Luessi
- Focus Program Translational Neuroscience, Rhine Main Neuroscience Network, Department of Neurology, University Medical Center Mainz, Johannes Gutenberg University Mainz, Langenbeckstr 1, 55131 Mainz, Germany
| | | | | |
Collapse
|
14
|
Flupirtine, a re-discovered drug, revisited. Inflamm Res 2013; 62:251-8. [PMID: 23322112 DOI: 10.1007/s00011-013-0592-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 12/20/2012] [Accepted: 01/02/2013] [Indexed: 12/15/2022] Open
Abstract
Flupirtine was developed long before K(V)7 (KCNQ) channels were known. However, it was clear from the beginning that flupirtine is neither an opioid nor a nonsteroidal anti-inflammatory analgesic. Its unique muscle relaxing activity was discovered by serendipity. In the meantime, broad and intensive research has resulted in a partial clarification of its mode of action. Flupirtine is the first therapeutically used K(V)7 channel activator with additional GABA(A)ergic mechanisms and thus the first representative of a novel class of analgesics. The presently accepted main mode of its action, potassium K(V)7 (KCNQ) channel activation, opens a series of further therapeutic possibilities. One of them has now been realized: its back-up compound, the bioisostere retigabine, has been approved for the treatment of epilepsy.
Collapse
|
15
|
Nodera H, Spieker A, Sung M, Rutkove S. Neuroprotective effects of Kv7 channel agonist, retigabine, for cisplatin-induced peripheral neuropathy. Neurosci Lett 2011; 505:223-7. [DOI: 10.1016/j.neulet.2011.09.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 09/09/2011] [Accepted: 09/11/2011] [Indexed: 10/17/2022]
|
16
|
Yu F, Liu Y, Wang Y, Yin J, Wang H, Liu W, Peng B, He X. Protective effect of the KCNQ activator flupirtine on a model of repetitive febrile seizures. Epilepsy Res 2011; 97:64-72. [PMID: 21831598 DOI: 10.1016/j.eplepsyres.2011.07.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 07/07/2011] [Accepted: 07/12/2011] [Indexed: 12/30/2022]
Abstract
Activation of KCNQ-channels has been shown to decrease or reduce the propagation of neuronal excitation in the immature central nervous system, and KCNQ activators represent a new class of anticonvulsant compounds. Their effectiveness has been demonstrated in many seizure models but not in repetitive febrile seizures (RFS) models. This study aimed to test whether the KCNQ channel activator flupirtine is also effective for RFS in rats. RFS were induced in Sprague-Dawley (SD) rats at postnatal day 10 (P10) in a warm water bath for eight consecutive days with or without the pre-administration of flupirtine or phenobarbital. As results, both drugs significantly increased the latency and decreased the rate of febrile seizures. Furthermore, seizures in the flupirtine group had a significantly shorter duration and were less severe compared with the phenobarbital group. The flupirtine-treated group showed less impairment in learning and memory and less obvious pathological changes in the brain following RFS compared with the phenobarbital-treated group. In summary, flupirtine appears to be effective in RFS prophylaxis and may merit further study as a candidate for the treatment of RFS in infants and children.
Collapse
Affiliation(s)
- Fang Yu
- Wuhan University School of Basic Medical Sciences, Wuhan 430071, China
| | | | | | | | | | | | | | | |
Collapse
|
17
|
Rau CR, Hein K, Sättler MB, Kretzschmar B, Hillgruber C, McRae BL, Diem R, Bähr M. Anti-inflammatory effects of FTY720 do not prevent neuronal cell loss in a rat model of optic neuritis. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 178:1770-81. [PMID: 21406175 PMCID: PMC3078467 DOI: 10.1016/j.ajpath.2011.01.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Revised: 12/08/2010] [Accepted: 01/04/2011] [Indexed: 11/24/2022]
Abstract
In multiple sclerosis, long-term disability is caused by axonal and neuronal damage. Established therapies target primarily the inflammatory component of the disease, but fail to prevent neurodegeneration. Fingolimod (codenamed FTY720) is an oral sphingosine 1-phosphate (S1P) receptor modulator with promising results in phase II trials in multiple sclerosis patients and is under further development as a novel treatment for multiple sclerosis. To evaluate whether FTY720 has neuroprotective properties, we tested this drug in a rat model of myelin oligodendrocyte glycoprotein-induced optic neuritis. FTY720 exerted significant anti-inflammatory effects during optic neuritis and reduced inflammation, demyelination, and axonal damage; however, FTY720 treatment did not prevent apoptosis of retinal ganglion cells (RGCs), the neurons that form the axons of the optic nerve. Consistent with this lack of effect on RGC survival, FTY720 treatment did not improve visual function, nor did it prevent apoptosis of RGCs in vitro. We observed a persistent activation of apoptotic signaling pathways in RGCs under FTY720 treatment, a possible underlying mechanism for the lack of neuroprotection in the presence of strong anti-inflammatory effects, Furthermore, FTY720 shifted the remaining inflammation in the optic nerve toward neurotoxicity by modest up-regulation of potential neurotoxic cytokines. We conclude that FTY720-induced anti-inflammation and axon protection did not of itself protect neurons from apoptotic cell death.
Collapse
Affiliation(s)
- Christian R. Rau
- Department of Neurology, University Medicine Göttingen, Göttingen, Germany
| | - Katharina Hein
- Department of Neurology, University Medicine Göttingen, Göttingen, Germany
| | - Muriel B. Sättler
- Department of Neurology, University Medicine Göttingen, Göttingen, Germany
| | | | - Carina Hillgruber
- Department of Neurology, University Medicine Göttingen, Göttingen, Germany
| | - Bradford L. McRae
- Department of Pharmacology, Abbott Bioresearch Center, Worcester, Massachusetts
| | - Ricarda Diem
- Department of Neurology, University of the Saarland, Homburg/Saar, Germany
| | - Mathias Bähr
- Department of Neurology, University Medicine Göttingen, Göttingen, Germany
| |
Collapse
|
18
|
Abstract
BACKGROUND Perivascular adipose tissue secretes an adipocyte-derived relaxing factor (ADRF) that opens voltage-dependent K (Kv) channels in peripheral arteries. We studied the role of KCNQ-type Kv channels and tested the hypothesis that hydrogen sulfide (H2S) could be an ADRF. METHODS We performed isometric contraction studies on systemic arteries of rats and mice. RESULTS In mesenteric arteries and aortas without perivascular adipose tissue, the KCNQ channel openers retigabine, VRX0530727, VRX0621238, and VRX0621688 produced concentration-dependent vasorelaxation; VRX0621688 was the most potent vasodilator. The KCNQ inhibitor XE991 (30 micromol/l) blocked the effects of both the drugs and ADRF. Inhibitors of cystathionine gamma lyase (CSE) beta-cyano-L-alanine (BCA, 5 mmol/l) and 4-propargyl glycine (PPG, 10 mmol/l) also blocked the relaxations. CSE is expressed in perivascular adipose tissue and endogenously generates H2S. The H2S donor NaHS produced concentration-dependent vasorelaxation, which was also blocked by XE991. The vasodilatory capacities of retigabine, VRX0530727, VRX0621238, and VRX0621688 were preserved following inhibition of H2S generation in perivascular fat. CONCLUSION We suggest that KCNQ channel opening is a powerful mechanism to produce vasorelaxation of systemic arteries in rats and mice. Furthermore, KCNQ channels play a major role in the paracrine control of vascular tone by perivascular adipose tissue, which is at least in part mediated or modulated by H2S. In conditions of reduced H2S release from perivascular adipose tissue, these paracrine effects can be mimicked by synthetic KCNQ channel openers.
Collapse
|
19
|
Abstract
Flupirtine is a centrally acting, non-opioid analgesic that is available in a number of European countries for the treatment of a variety of pain states. The therapeutic benefits seen with flupirtine relate to its unique pharmacological properties. Flupirtine displays indirect NDMA receptor antagonism via activation of potassium channels and is the first representative of a pharmacological class denoted the 'selective neuronal potassium channel openers'. The generation of the M-current is facilitated by flupirtine via the opening of neuronal Kv7 potassium channels. The opening of these channels inhibits exaggerated neuronal action potential generation and controls neuronal excitability. Neuronal hyperexcitability is a physiological component of many pain states such as chronic pain, migraine and neurogenic pain. Although large-scale clinical trials are lacking, the clinical trial database available to date from smaller-scale studies, together with extensive clinical experience, indicate that flupirtine effectively reduces chronic musculoskeletal pain, migraine and neuralgias, amongst other types of pain. In addition, flupirtine produces, at recommended clinical doses, muscle-relaxing effects in the presence of abnormally increased muscle tension. Its analgesic and muscle-relaxant properties were comparable to tramadol and chlormezanone, respectively, in two prospective trials in patients with lower back pain. Cytoprotective, anti-apoptotic and antioxidant properties have also been associated with flupirtine use in a small number of studies to date. When provided as combination therapy with morphine, flupirtine increases the antinociceptive activity of morphine 4-fold. Flupirtine displays superior tolerability when compared with tramadol and pentazocine. The most common adverse effects associated with flupirtine use are drowsiness, dizziness, heartburn, dry mouth, fatigue and nausea. With respect to its molecular structure, mechanism of action and adverse event profile, flupirtine is a unique drug. Flupirtine is an analgesic with many potential therapeutic benefits that may prove useful in the treatment of many disease states.
Collapse
Affiliation(s)
- Jacques Devulder
- Department of Anaesthesia, Section Pain Clinic, Ghent University Hospital, Ghent, Belgium.
| |
Collapse
|
20
|
Sättler MB, Bähr M. Future neuroprotective strategies. Exp Neurol 2010; 225:40-7. [DOI: 10.1016/j.expneurol.2009.08.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Revised: 08/18/2009] [Accepted: 08/19/2009] [Indexed: 12/27/2022]
|
21
|
Herz J, Zipp F, Siffrin V. Neurodegeneration in autoimmune CNS inflammation. Exp Neurol 2010; 225:9-17. [DOI: 10.1016/j.expneurol.2009.11.019] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Accepted: 11/24/2009] [Indexed: 02/06/2023]
|
22
|
Klawe C, Maschke M. Flupirtine: pharmacology and clinical applications of a nonopioid analgesic and potentially neuroprotective compound. Expert Opin Pharmacother 2009; 10:1495-500. [DOI: 10.1517/14656560902988528] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
|