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García-Ayuso D, Di Pierdomenico J, Valiente-Soriano FJ, Martínez-Vacas A, Agudo-Barriuso M, Vidal-Sanz M, Picaud S, Villegas-Pérez MP. β-alanine supplementation induces taurine depletion and causes alterations of the retinal nerve fiber layer and axonal transport by retinal ganglion cells. Exp Eye Res 2019; 188:107781. [PMID: 31473259 DOI: 10.1016/j.exer.2019.107781] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 08/26/2019] [Accepted: 08/28/2019] [Indexed: 11/30/2022]
Abstract
To study the effect of taurine depletion induced by β-alanine supplementation in the retinal nerve fiber layer (RNFL), and retinal ganglion cell (RGC) survival and axonal transport. Albino Sprague-Dawley rats were divided into two groups: one group received β-alanine supplementation (3%) in the drinking water during 2 months to induce taurine depletion, and the other group received regular water. After one month, half of the rats from each group were exposed to light. Retinas were analyzed in-vivo using Spectral-Domain Optical Coherence Tomography (SD-OCT). Prior to processing, RGCs were retrogradely traced with fluorogold (FG) applied to both superior colliculi, to assess the state of their retrograde axonal transport. Retinas were dissected as wholemounts, surviving RGCs were immunoidentified with Brn3a, and the RNFL with phosphorylated high-molecular-weight subunit of the neurofilament triplet (pNFH) antibodies. β-alanine supplementation decreases significantly taurine plasma levels and causes a significant reduction of the RNFL thickness that is increased after light exposure. An abnormal pNFH immunoreactivity in some RGC bodies, their proximal dendrites and axons, and a further diminution of the mean number of FG-traced RGCs compared with Brn3a+RGCs, indicate that their retrograde axonal transport is affected. In conclusion, taurine depletion causes RGC loss and axonal transport impairment. Finally, our results suggest that care should be taken when ingesting β-alanine supplements due to the limited understanding of their potential adverse effects.
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Affiliation(s)
- Diego García-Ayuso
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain.
| | - Johnny Di Pierdomenico
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Francisco J Valiente-Soriano
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Ana Martínez-Vacas
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Marta Agudo-Barriuso
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Manuel Vidal-Sanz
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Serge Picaud
- INSERM U968, Institut de la Vision, Paris, France; Sorbonnes Universités, INSERM U968, CNRS UMR 7210, Institut de la Vision, 75012, Paris, France
| | - María P Villegas-Pérez
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain.
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Tak AZA, Şengül Y, Ekmekçi B, Karadağ AS. Comparison of optic coherence tomography results in patients with diagnosed epilepsy: Findings in favor of neurodegeneration. Epilepsy Behav 2019; 92:140-144. [PMID: 30658322 DOI: 10.1016/j.yebeh.2018.12.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Revised: 12/17/2018] [Accepted: 12/22/2018] [Indexed: 01/26/2023]
Abstract
BACKGROUND Epilepsy is a chronic neurological disease characterized with recurrent seizures. Progressive neuronal degeneration is a common consequence of long-term and/or recurrent seizure activity in epilepsy. Optical coherence tomography (OCT) is a new medical imaging technique that displays biological tissue layers as high-resolution tomographic sections. The aim of our study was to evaluate OCT findings in patients with epilepsy and to compare OCT findings in terms of disease duration, presence of status, seizure frequency, and drug use. METHODS Forty-three patients who had epilepsy according to the Commission on Classification and Terminology of the International League Against Epilepsy (ILAE) in 2010 and 40 healthy controls were recruited for the study. Disease duration, seizure frequency, status history, and multiple drug use were noted. Retinal nerve fiber layer (RNLF), ganglion cell layer (GCL), inner-plexiform layer (IPL), and choroid thinning were analyzed by using spectral OCT. RESULTS The mean RNFL values are 101.48 ± 11.33 in the patient group and 108.76 ± 8.37 in the control group (p = 0.001). The mean GCL thickness values in the patient and control groups are 1.14 ± 0.12 and 1.22 ± 0.05, (p < 0.001). The mean IPL thickness is 0.93 ± 0.09 in the patient group and 0.97 ± 0.05 in the control group (p = 0.02). Choroid thickness is significantly increased in the patient group (p < 0.001). CONCLUSIONS Demonstration of RNFL, IPL, and GCL thinning might indicate neurodegeneration, and choroid thickening indicates neuroinflammation. We found no association between disease duration, seizure frequency, status history, and multiple drug use and OCT parameters. Further studies with larger patient groups should clarify the matter.
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Affiliation(s)
- Ali Zeynal Abidin Tak
- Adıyaman University, School of Medicine, Department of Neurology, Siteler Mahallesi, Atatürk Bulvarı, No: 411, Adiyaman, Turkey.
| | - Yıldızhan Şengül
- Bezmialem Vakif University Hospital, Department of Neurology, Adnan Menderes Bulvarı, Vatan Caddesi, 34093 Fatih, İstanbul, Turkey
| | - Burcu Ekmekçi
- Antalya Atatürk State Hospital, Department of Neurology Antalya, Anafartalar Cad. Üçgen Mevkii Muratpaşa, Antalya, Turkey
| | - Ayşe Sevgi Karadağ
- Adıyaman University, School of Medicine, Department of Ophthalmology, Siteler Mahallesi, Atatürk Bulvarı, No: 411, Adiyaman, Turkey
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Walters DC, Arning E, Bottiglieri T, Jansen EEW, Salomons GS, Brown MN, Schmidt MA, Ainslie GR, Roullet JB, Gibson KM. Metabolomic analyses of vigabatrin (VGB)-treated mice: GABA-transaminase inhibition significantly alters amino acid profiles in murine neural and non-neural tissues. Neurochem Int 2019; 125:151-162. [PMID: 30822440 DOI: 10.1016/j.neuint.2019.02.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 02/19/2019] [Accepted: 02/20/2019] [Indexed: 11/18/2022]
Abstract
The anticonvulsant vigabatrin (VGB; SabrilR) irreversibly inhibits GABA transaminase to increase neural GABA, yet its mechanism of retinal toxicity remains unclear. VGB is suggested to alter several amino acids, including homocarnosine, β-alanine, ornithine, glycine, taurine, and 2-aminoadipic acid (AADA), the latter a homologue of glutamic acid. Here, we evaluate the effect of VGB on amino acid concentrations in mice, employing a continuous VGB infusion (subcutaneously implanted osmotic minipumps), dose-escalation paradigm (35-140 mg/kg/d, 12 days), and amino acid quantitation in eye, visual and prefrontal cortex, total brain, liver and plasma. We hypothesized that continuous VGB dosing would reveal numerous hitherto undescribed amino acid disturbances. Consistent amino acid elevations across tissues included GABA, β-alanine, carnosine, ornithine and AADA, as well as neuroactive aspartic and glutamic acids, serine and glycine. Maximal increase of AADA in eye occurred at 35 mg/kg/d (41 ± 2 nmol/g (n = 21, vehicle) to 60 ± 8.5 (n = 8)), and at 70 mg/kg/d for brain (97 ± 6 (n = 21) to 145 ± 6 (n = 6)), visual cortex (128 ± 6 to 215 ± 19) and prefrontal cortex (124 ± 11 to 200 ± 13; mean ± SEM; p < 0.05), the first demonstration of tissue AADA accumulation with VGB in mammal. VGB effects on basic amino acids, including guanidino-species, suggested the capacity of VGB to alter urea cycle function and nitrogen disposal. The known toxicity of AADA in retinal glial cells highlights new avenues for assessing VGB retinal toxicity and other off-target effects.
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Affiliation(s)
- Dana C Walters
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA
| | - Erland Arning
- Baylor Scott & White Research Institute, Institute of Metabolic Disease, Dallas, TX, USA
| | - Teodoro Bottiglieri
- Baylor Scott & White Research Institute, Institute of Metabolic Disease, Dallas, TX, USA
| | - Erwin E W Jansen
- Metabolic Laboratory, Department of Clinical Chemistry, Amsterdam University Medical Center, the Netherlands
| | - Gajja S Salomons
- Metabolic Laboratory, Department of Clinical Chemistry, Amsterdam University Medical Center, the Netherlands
| | - Madalyn N Brown
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA
| | - Michelle A Schmidt
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA
| | - Garrett R Ainslie
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA
| | - Jean-Baptiste Roullet
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA
| | - K Michael Gibson
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA.
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Walters DC, Jansen EEW, Ainslie GR, Salomons GS, Brown MN, Schmidt MA, Roullet J, Gibson KM. Preclinical tissue distribution and metabolic correlations of vigabatrin, an antiepileptic drug associated with potential use-limiting visual field defects. Pharmacol Res Perspect 2019; 7:e00456. [PMID: 30631446 PMCID: PMC6321982 DOI: 10.1002/prp2.456] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 12/06/2018] [Accepted: 12/07/2018] [Indexed: 01/30/2023] Open
Abstract
Vigabatrin (VGB; (S)-(+)/(R)-(-) 4-aminohex-5-enoic acid), an antiepileptic irreversibly inactivating GABA transaminase (GABA-T), manifests use-limiting ocular toxicity. Hypothesizing that the active S enantiomer of VGB would preferentially accumulate in eye and visual cortex (VC) as one potential mechanism for ocular toxicity, we infused racemic VGB into mice via subcutaneous minipump at 35, 70, and 140 mg/kg/d (n = 6-8 animals/dose) for 12 days. VGB enantiomers, total GABA and β-alanine (BALA), 4-guanidinobutyrate (4-GBA), and creatine were quantified by mass spectrometry in eye, brain, liver, prefrontal cortex (PFC), and VC. Plasma VGB concentrations increased linearly by dose (3 ± 0.76 (35 mg/kg/d); 15.1 ± 1.4 (70 mg/kg/d); 34.6 ± 3.2 μmol/L (140 mg/kg/d); mean ± SEM) with an S/R ratio of 0.74 ± 0.02 (n = 14). Steady state S/R ratios (35, 70 mg/kg/d doses) were highest in eye (5.5 ± 0.2; P < 0.0001), followed by VC (3.9 ± 0.4), PFC (3.6 ± 0.3), liver (2.9 ± 0.1), and brain (1.5 ± 0.1; n = 13-14 each). Total VGB content of eye exceeded that of brain, PFC and VC at all doses. High-dose VGB diminished endogenous metabolite production, especially in PFC and VC. GABA significantly increased in all tissues (all doses) except brain; BALA increases were confined to liver and VC; and 4-GBA was prominently increased in brain, PFC and VC (and eye at high dose). Linear correlations between enantiomers and GABA were observed in all tissues, but only in PFC/VC for BALA, 4-GBA, and creatine. Preferential accumulation of the VGB S isomer in eye and VC may provide new insight into VGB ocular toxicity.
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Affiliation(s)
- Dana C. Walters
- Department of PharmacotherapyCollege of Pharmacy and Pharmaceutical SciencesWashington State UniversitySpokaneWashington
| | - Erwin E. W. Jansen
- Metabolic LaboratoryDepartment of Clinical ChemistryAmsterdam University Medical CenterAmsterdamThe Netherlands
| | - Garrett R. Ainslie
- Department of PharmacotherapyCollege of Pharmacy and Pharmaceutical SciencesWashington State UniversitySpokaneWashington
| | - Gajja S. Salomons
- Metabolic LaboratoryDepartment of Clinical ChemistryAmsterdam University Medical CenterAmsterdamThe Netherlands
| | - Madalyn N. Brown
- Department of PharmacotherapyCollege of Pharmacy and Pharmaceutical SciencesWashington State UniversitySpokaneWashington
| | - Michelle A. Schmidt
- Department of PharmacotherapyCollege of Pharmacy and Pharmaceutical SciencesWashington State UniversitySpokaneWashington
| | - Jean‐Baptiste Roullet
- Department of PharmacotherapyCollege of Pharmacy and Pharmaceutical SciencesWashington State UniversitySpokaneWashington
| | - K. M. Gibson
- Department of PharmacotherapyCollege of Pharmacy and Pharmaceutical SciencesWashington State UniversitySpokaneWashington
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News on the journal Neurological Sciences in 2017. Neurol Sci 2018; 39:15-21. [PMID: 29327225 DOI: 10.1007/s10072-017-3241-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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