title: Disturbance of energy and redox homeostasis and reduction of Na+,K+-ATPase activity provoked by in vivo intracerebral administration of ethylmalonic acid to young rats.
abstract: Ethylmalonic acid (EMA) accumulation occurs in various metabolic diseases with neurological manifestation, including short acyl-CoA dehydrogenase deficiency (SCADD) and ethylmalonic encephalopathy (EE). Since pathophysiological mechanisms responsible for brain damage in these disorders are still poorly understood, we investigated the ex vivo effects of acute intrastriatal administration of EMA on important parameters of energy and redox homeostasis in striatum from young rats. We evaluated CO(2) production from glucose, glucose utilization and lactate production, as well as the activities of the citric acid cycle (CAC) enzymes, the electron transfer chain (ETC) complexes II-IV (oxidative phosphorylation, OXPHOS) and synaptic Na(+),K(+)-ATPase. We also tested the effect of EMA on malondialdehyde (MDA) levels (marker of lipid oxidation) and reduced glutathione (GSH) levels. EMA significantly reduced CO(2) production, increased glucose utilization and lactate production, and reduced the activities of citrate synthase and of complexes II and II-III of the ETC, suggesting an impairment of CAC and OXPHOS. EMA injection also reduced Na(+),K(+)-ATPase activity and GSH concentrations, whereas MDA levels were increased. Furthermore, EMA-induced diminution of Na(+),K(+)-ATPase activity and reduction of GSH levels were prevented, respectively, by the antioxidants melatonin and N-acetylcysteine, indicating that reactive species were involved in these effects. Considering the importance of CAC and ETC for energy production and Na(+),K(+)-ATPase for the maintenance of the cell membrane potential, the present data indicate that EMA compromises mitochondrial homeostasis and neurotransmission in striatum. We presume that these pathomechanisms may be involved to a certain extent in the neurological damage found in patients affected by SCADD and EE.
authors.affiliation: Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Luciana
authors.initials: L
authors.lastname: Ritter
authors.affiliation: Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Daniele
authors.initials: D
authors.lastname: Kleemann
authors.affiliation: Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Fernanda Hermes
authors.initials: FH
authors.lastname: Hickmann
authors.affiliation: Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Alexandre Umpierrez
authors.initials: AU
authors.lastname: Amaral
authors.affiliation: Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil.
authors.forename: Ângela
authors.initials: Â
authors.lastname: Sitta
authors.affiliation: Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil.
authors.forename: Moacir
authors.initials: M
authors.lastname: Wajner
authors.affiliation: Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil. Electronic address: cesar.rib@gmail.com.
authors.forename: César Augusto João
authors.initials: CA
authors.lastname: Ribeiro
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D002245:Carbon Dioxide / Q000378:metabolism; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism; D042963:Electron Transport Complex II / Q000378:metabolism; D014450:Electron Transport Complex III / Q000378:metabolism; D004734:Energy Metabolism / Q000187:drug effects*; D005947:Glucose / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D006706:Homeostasis / Q000187:drug effects*; D007276:Injections, Intraventricular; D007773:Lactates / Q000378:metabolism; D008297:Male; D008314:Malonates / Q000008:administration & dosage / Q000494:pharmacology*; D008315:Malondialdehyde / Q000378:metabolism; D008550:Melatonin / Q000494:pharmacology; D010084:Oxidation-Reduction / Q000187:drug effects; D017208:Rats, Wistar; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013569:Synapses / Q000187:drug effects / Q000201:enzymology
chemical_list: D000975:Antioxidants; D007773:Lactates; D008314:Malonates; D002245:Carbon Dioxide; C038080:ethylmalonic acid; D008315:Malondialdehyde; D042963:Electron Transport Complex II; D014450:Electron Transport Complex III; D000254:Sodium-Potassium-Exchanging ATPase; D005978:Glutathione; D005947:Glucose; D008550:Melatonin; D000111:Acetylcysteine
keywords: Energy metabolism; Ethylmalonic acid; Redox homeostasis; Striatum; Synaptic Na(+),K(+)-ATPase