Pharmacological Interventions to Ameliorate Neuropathological Symptoms in a Mouse Model of Lafora Disease

14 páginas; 9 figuras.Lafora disease (LD, OMIM 254780) is a rare fatal neurodegenerative disorder that usually occurs during childhood with generalized tonic-clonic seizures, myoclonus, absences, drop attacks or visual seizures. Unfortunately, at present, available treatments are only palliatives and no curative drugs are available yet. The hallmark of the disease is the accumulation of insoluble polyglucosan inclusions, called Lafora bodies (LBs), within the neurons but also in heart, muscle and liver cells. Mouse models lacking functional EPM2A or EPM2B genes (the two major loci related to the disease) recapitulate the Lafora disease phenotype: they accumulate polyglucosan inclusions, show signs of neurodegeneration and have a dysregulation of protein clearance and endoplasmic reticulum stress response. In this study, we have subjected a mouse model of LD (Epm2b-/-) to different pharmacological interventions aimed to alleviate protein clearance and endoplasmic reticulum stress. We have used two chemical chaperones, trehalose and 4-phenylbutyric acid. In addition, we have used metformin, an activator of AMP-activated protein kinase (AMPK), as it has a recognized neuroprotective role in other neurodegenerative diseases. Here, we show that treatment with 4-phenylbutyric acid or metformin decreases the accumulation of Lafora bodies and polyubiquitin protein aggregates in the brain of treated animals. 4-Phenylbutyric acid and metformin also diminish neurodegeneration (measured in terms of neuronal loss and reactive gliosis) and ameliorate neuropsychological tests of Epm2b-/- mice. As these compounds have good safety records and are already approved for clinical uses on different neurological pathologies, we think that the translation of our results to the clinical practice could be straightforward.This work was supported by grants from the Spanish Ministry of Education and Science SAF2011-27442, Fundació La Marato de TV3 (ref. 100130) and an ACCI2012 action from CIBERER. A.B. holds a postdoctoral fellowship from the Program “Junta para la Ampliación de Estudios” (JAE-Doc) co-funded by the European Social Fund (ESF).Peer reviewe

Rare coding variants in genes encoding GABA(A) receptors in genetic generalised epilepsies : an exome-based case-control study

Background Genetic generalised epilepsy is the most common type of inherited epilepsy. Despite a high concordance rate of 80% in monozygotic twins, the genetic background is still poorly understood. We aimed to investigate the burden of rare genetic variants in genetic generalised epilepsy. Methods For this exome-based case-control study, we used three different genetic generalised epilepsy case cohorts and three independent control cohorts, all of European descent. Cases included in the study were clinically evaluated for genetic generalised epilepsy. Whole-exome sequencing was done for the discovery case cohort, a validation case cohort, and two independent control cohorts. The replication case cohort underwent targeted next-generation sequencing of the 19 known genes encoding subunits of GABA(A) receptors and was compared to the respective GABA(A) receptor variants of a third independent control cohort. Functional investigations were done with automated two-microelectrode voltage clamping in Xenopus laevis oocytes. Findings Statistical comparison of 152 familial index cases with genetic generalised epilepsy in the discovery cohort to 549 ethnically matched controls suggested an enrichment of rare missense (Nonsyn) variants in the ensemble of 19 genes encoding GABA(A) receptors in cases (odds ratio [OR] 2.40 [95% CI 1.41-4.10]; p(Nonsyn)=0.0014, adjusted p(Nonsyn)=0.019). Enrichment for these genes was validated in a whole-exome sequencing cohort of 357 sporadic and familial genetic generalised epilepsy cases and 1485 independent controls (OR 1.46 [95% CI 1.05-2.03]; p(Nonsyn)=0.0081, adjusted p(Nonsyn)=0.016). Comparison of genes encoding GABA(A) receptors in the independent replication cohort of 583 familial and sporadic genetic generalised epilepsy index cases, based on candidate-gene panel sequencing, with a third independent control cohort of 635 controls confirmed the overall enrichment of rare missense variants for 15 GABA(A) receptor genes in cases compared with controls (OR 1.46 [95% CI 1.02-2.08]; p(Nonsyn)=0.013, adjusted p(Nonsyn)=0.027). Functional studies for two selected genes (GABRB2 and GABRA5) showed significant loss-of-function effects with reduced current amplitudes in four of seven tested variants compared with wild-type receptors. Interpretation Functionally relevant variants in genes encoding GABA(A) receptor subunits constitute a significant risk factor for genetic generalised epilepsy. Examination of the role of specific gene groups and pathways can disentangle the complex genetic architecture of genetic generalised epilepsy. Copyright (C) 2018 The Author(s). Published by Elsevier Ltd.Peer reviewe

Nueva mutación en el gen STXBP1 en un paciente con síndrome de Ohtahara no lesional

Resumen: Introducción: El síndrome de Ohtahara (SO, OMIM#308350, ORPHA1934) es una encefalopatía epiléptica de inicio precoz (EEIP) caracterizada por espasmos, crisis epilépticas intratables, un trazado electroencefalográfico de brote-supresión y retraso psicomotor grave. En la mayoría de los pacientes con SO se han identificado mutaciones en el gen STXBP1, que codifica para la proteína de unión a sintaxina 1 y que está implicado en el mecanismo de exocitosis de las vesículas sinápticas. Paciente y resultados: Se presenta el caso clínico de un varón de 19 meses de edad diagnosticado de SO en el que se ha identificado una mutación no descrita (c.1249 + 2T > C, G417AfsX7) en el gen STXBP1. La mutación está localizada en uno de los sitios donadores implicados en el procesamiento del ARNm del gen, lo que produce la pérdida del exón 14 y el posterior truncamiento de la proteína que codifica. Conclusiones: Esta nueva mutación en el gen STXBP1, identificada en un paciente sin lesión cerebral estructural subyacente, amplía el espectro mutacional asociado a este devastador síndrome epiléptico. Abstract: Introduction: Ohtahara syndrome (OS, OMIM#308350, ORPHA1934) is an early-onset epileptic encephalopathy (EOEE) characterised by spasms, intractable seizures, suppression-burst pattern on the electroencephalogram, and severe psychomotor retardation. Mutations in STXBP1 —a gene that codes for syntaxin binding protein 1 and is involved in synaptic vesicle exocytosis— has been identified in most patients with OS. Patient and results: We report the case of a 19-month-old child with OS who displays a previously unreported mutation in STXBP1 (c.1249 + 2T > C, G417AfsX7). This mutation is located in a donor splice site and eliminates exon 14, resulting in a truncated protein. Conclusion: This previously unreported STXBP1 mutation in a subject with Ohtahara syndrome and non-lesional magnetic resonance imaging (MRI) broadens the mutational spectrum associated with this devastating epileptic syndrome. Palabras clave: Genética clínica, Encefalopatía epiléptica de inicio precoz, Epilepsia, Síndrome de Ohtahara, STXBP1, Keywords: Clinical genetics, Early-onset epileptic encephalopathy, Epilepsy, Ohtahara syndrome, STXBP

Novel mutation in STXBP1 gene in a patient with non-lesional Ohtahara syndrome

Introduction: Ohtahara syndrome (OS, OMIM #308350, ORPHA1934) is an early-onset epileptic encephalopathy (EOEE) characterised by spasms, intractable seizures, suppression-burst pattern on the electroencephalogram, and severe psychomotor retardation. Mutations in STXBP1 – a gene that codes for syntaxin binding protein 1 and is involved in synaptic vesicle exocytosis – has been identified in most patients with OS. Patient and results: We report the case of a 19-month-old child with OS who displays a previously unreported mutation in STXBP1 (c.1249+2T>C, G417AfsX7). This mutation is located in a donor splice site and eliminates exon 14, resulting in a truncated protein. Conclusion: This previously unreported STXBP1 mutation in a subject with Ohtahara syndrome and non-lesional magnetic resonance imaging (MRI) broadens the mutational spectrum associated with this devastating epileptic syndrome. Resumen: Introducción: El síndrome de Ohtahara (SO, OMIM #308350, ORPHA1934) es una encefalopatía epiléptica de inicio precoz (EEIP) caracterizada por espasmos, crisis epilépticas intratables, un trazado electroencefalográfico de brote-supresión y retraso psicomotor grave. En la mayoría de los pacientes con SO se han identificado mutaciones en el gen STXBP1, que codifica para la proteína de unión a sintaxina 1 y que está implicado en el mecanismo de exocitosis de las vesículas sinápticas. Paciente y resultados: Se presenta el caso clínico de un varón de 19 meses de edad diagnosticado de SO en el que se ha identificado una mutación no descrita (c.1249+2T>C, G417AfsX7) en el gen STXBP1. La mutación está localizada en uno de los sitios donadores implicados en el procesamiento del ARNm del gen, lo que produce la pérdida del exón 14 y el posterior truncamiento de la proteína que codifica. Conclusiones: Esta nueva mutación en el gen STXBP1, identificada en un paciente sin lesión cerebral estructural subyacente, amplía el espectro mutacional asociado a este devastador síndrome epiléptico. Keywords: Clinical genetics, Early-onset epileptic encephalopathy, Epilepsy, Ohtahara syndrome, STXBP1, Palabras clave: Genética clínica, Encefalopatía epiléptica de inicio precoz, Epilepsia, Síndrome de Ohtahara, STXBP

Drug-resistant epilepsy: Definition and treatment alternatives

Introduction: Drug-resistant epilepsy affects 25% of all epileptic patients, and quality of life decreases in these patients due to their seizures. Early detection is crucial in order to establish potential treatment alternatives and determine if the patient is a surgical candidate. Development: PubMed search for articles, recommendations published by major medical societies, and clinical practice guidelines for drug-resistant epilepsy and its medical and surgical treatment options. Evidence and recommendations are classified according to the criteria of the Oxford Centre for Evidence-Based Medicine (2001) and the European Federation of Neurological Societies (2004) for therapeutic actions. Conclusions: Identifying patients with drug-resistant epilepsy is important for optimising drug therapy. Experts recommend rational polytherapy with antiepileptic drugs to find more effective combinations with fewer adverse effects. When adequate seizure control is not achieved, a presurgical evaluation in an epilepsy referral centre is recommended. These evaluations explore how to resect the epileptogenic zone without causing functional deficits in cases in which this is feasible. If resective surgery is not achievable, palliative surgery or neurostimulation systems (including vagus nerve, trigeminal nerve, or deep brain stimulation) may be an option. Other treatment alternatives such as ketogenic diet may also be considered in selected patients. Resumen: Introducción: La epilepsia resistente al tratamiento médico afecta a una cuarta parte de los pacientes con epilepsia. Como consecuencia de las crisis estos pacientes presentan una peor calidad de vida, por lo que es fundamental su diagnóstico para establecer posibles alternativas terapéuticas e iniciar una valoración prequirúrgica. Desarrollo: Búsqueda de artículos en PubMed y recomendaciones de las Guías de Práctica Clínica (GPC) y Sociedades Científicas más relevantes, referentes a epilepsia refractaria y al tratamiento médico y quirúrgico. Se clasifican las evidencias y recomendaciones según los criterios pronósticos del Oxford Centre for Evidence Based Medicine (2001) y de la European Federation of Neurological Societies (2004) para actuaciones terapéuticas. Conclusiones: La identificación de los pacientes con epilepsia refractaria es importante para optimizar el tratamiento farmacológico. Se recomienda el empleo de una politerapia racional de fármacos antiepilépticos, buscando combinaciones que aumenten la eficacia y minimicen los efectos adversos. Cuando no se consigue el control adecuado de las crisis es necesario realizar una valoración prequirúrgica en un centro especializado, con el fin de resecar la zona epileptógena sin producir déficits al paciente en los casos en los que sea posible. En caso contrario se recurrirá a procedimientos de cirugía paliativa o sistemas de neuroestimulación (vagal, trigeminal o cerebral). Otras alternativas, como la dieta cetógena, también pueden considerarse en pacientes seleccionados. Keywords: Drug-resistant epilepsy, Rational combination therapy, Epilepsy surgery, Deep brain stimulation, Vagus nerve stimulation, Ketogenic diet, Palabras clave: Epilepsia refractaria, Politerapia racional, Cirugía epilepsia, Estimulación cerebral profunda, Estimulación vagal, Dieta cetógen

Epilepsia resistente a fármacos. Concepto y alternativas terapéuticas

Resumen: Introducción: La epilepsia resistente al tratamiento médico afecta a una cuarta parte de los pacientes con epilepsia. Como consecuencia de las crisis estos pacientes presentan una peor calidad de vida, por lo que es fundamental su diagnóstico para establecer posibles alternativas terapéuticas e iniciar una valoración prequirúrgica. Desarrollo: Búsqueda de artículos en PubMed y recomendaciones de las Guías de Práctica Clínica (GPC) y Sociedades Científicas más relevantes, referentes a epilepsia refractaria y al tratamiento médico y quirúrgico. Se clasifican las evidencias y recomendaciones según los criterios pronósticos del Oxford Center for Evidence Based Medicine (2001) y de la European Federation of Neurological Societies (2004) para actuaciones terapéuticas. Conclusiones: La identificación de los pacientes con epilepsia refractaria es importante para optimizar el tratamiento farmacológico. Se recomienda el empleo de una politerapia racional de fármacos antiepilépticos, buscando combinaciones que aumenten la eficacia y minimicen los efectos adversos. Cuando no se consigue el control adecuado de las crisis es necesario realizar una valoración prequirúrgica en un centro especializado, con el fin de resecar la zona epileptógena sin producir déficits al paciente en los casos en los que sea posible. En caso contrario se recurrirá a procedimientos de cirugía paliativa o sistemas de neuroestimulación (vagal, trigeminal o cerebral). Otras alternativas, como la dieta cetógena, también pueden considerarse en pacientes seleccionados. Abstract: Introduction: Drug-resistant epilepsy affects 25% of all epileptic patients, and quality of life decreases in these patients due to their seizures. Early detection is crucial in order to establish potential treatment alternatives and determine if the patient is a surgical candidate. Development: PubMed search for articles, recommendations published by major medical societies, and clinical practice guidelines for drug-resistant epilepsy and its medical and surgical treatment options. Evidence and recommendations are classified according to the criteria of the Oxford Centre for Evidence-Based Medicine (2001) and the European Federation of Neurological Societies (2004) for therapeutic actions. Conclusions: Identifying patients with drug-resistant epilepsy is important for optimising drug therapy. Experts recommend rational polytherapy with antiepileptic drugs to find more effective combinations with fewer adverse effects. When adequate seizure control is not achieved, a presurgical evaluation in an epilepsy referral centre is recommended. These evaluations explore how to resect the epileptogenic zone without causing functional deficits in cases in which this is feasible. If resective surgery is not achievable, palliative surgery or neurostimulation systems (including vagus nerve, trigeminal nerve, or deep brain stimulation) may be an option. Other treatment alternatives such as ketogenic diet may also be considered in selected patients. Palabras clave: Epilepsia refractaria, Politerapia racional, Cirugía epilepsia, Estimulación cerebral profunda, Estimulación vagal, Dieta cetógena, Keywords: Drug-resistant epilepsy, Rational combination therapy, Epilepsy surgery, Deep brain stimulation, Vagus nerve stimulation, Ketogenic die

Adsorption of 2,2′-bipyridyl onto sepiolite, attapulgite and smectite group clay minerals from anatolia: The FT-IR and FT-Raman spectra of surface and intercalated species.

The adsorption of 2,2-bipyridyl by natural sepiolite, attapulgite, hectorite, saponite and natural and ion exchanged (Mn, Fe, Co, Ni, Cu, Zn or Sn) bentonites has been investigated by FT-IR and FT-Raman spectroscopy. Spectroscopic results indicate that most of the adsorbed molecules are coordinated to either exchangeable cations (in the case of smectite group clays) or Lewis acidic centres (in the case of sepiolite and attapulgite) as bidentate ligands. The formation of monoanionic surface species has also been detected, to a relatively small extent. No physisorbed surface species has been observed. XRD patterns and UV-visible spectra of the samples are also recorded for additional information