RESUMO
Conflicting results have been reported concerning the toxicity of cerebrospinal fluid from patients with amyotrophic lateral sclerosis (ALS-CSF) when added to neuronal cultures. The possible toxic factor(s) and the exact mode of action (e.g. requirement of glial cells) have not been identified so far. Glutamate is a potential candidate for this toxic effect, since antagonists of ionotropic glutamate receptors have been shown to attenuate ALS-CSF toxicity. We studied the effects of ALS-CSF on mixed and motoneuron-enriched chick embryonic spinal cord cultures. We found a toxic action of ALS-CSF in both culture types which could not be attenuated by 5 kDa-filtration or 15 min 90 degrees C heating. Nevertheless, the metabotropic glutamate receptor (mGluR) group I antagonist 1-aminoindan-1,5-dicarboxylic acid, but also the group I agonist (s)-3,5-dihydroxyphenylglycine (DHPG) exerted protective effects against ALS-CSF toxicity. In this experimental setting, DHPG may functionally act via a receptor blockade due to sustained activation. No protective effect was seen with the mGluR group III inhibitor (RS)-alpha-cyclopropyl-4-phosphonophenylglycine (CPPG). Addition of DHPG did not increase the protective action of the AMPA inhibitor 6-chloro-4-hydroxyquinoline-2-carboxylic acid (6-CKU). Addition of l-glutamate did not mimic these toxic ALS-CSF effects in motoneuron-enriched cultures. Our experiments demonstrate that ALS-CSF toxicity is mediated by a small heat-resistant molecule which may act directly on neurons. Since blockade of group I mGluRs exerts a protective effect, the possibility of targeting these mGluRs pharmacologically in motoneuron disease should be kept in mind.
Assuntos
Esclerose Lateral Amiotrófica/líquido cefalorraquidiano , Líquido Cefalorraquidiano/efeitos dos fármacos , Antagonistas de Aminoácidos Excitatórios/farmacologia , Neurônios Motores/metabolismo , Receptores de Glutamato Metabotrópico/antagonistas & inibidores , Idoso , Animais , Contagem de Células/métodos , Morte Celular/efeitos dos fármacos , Morte Celular/fisiologia , Células Cultivadas , Líquido Cefalorraquidiano/química , Líquido Cefalorraquidiano/metabolismo , Embrião de Galinha , Técnicas de Cocultura/métodos , Relação Dose-Resposta a Droga , Feminino , Ácido Glutâmico/farmacologia , Glicina/análogos & derivados , Glicina/farmacologia , Humanos , Imuno-Histoquímica/métodos , Marcação In Situ das Extremidades Cortadas , Indanos/farmacologia , Indóis , Lectinas , Masculino , Pessoa de Meia-Idade , Neurônios Motores/efeitos dos fármacos , Receptores de Glutamato Metabotrópico/fisiologia , Medula Espinal/citologia , Fatores de TempoRESUMO
Glycogenosis type II (Pompe disease) is a lysosomal storage disease caused by deficiency of acid alpha-glucosidase (acid maltase). The disease is autosomal recessive inherited and is clinically and genetically heterogenous. The authors describe a 30-year-old woman affected by late-onset Pompe disease with vascular affection resembling atherosclerotic angiopathy of the elderly. Genetic analysis revealed two novel mutations (Ala237Val and Gly293Arg) in the acid alpha-glucosidase gene in this patient.