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2.
Biochim Biophys Acta Mol Basis Dis ; 1865(9): 2420-2427, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31181292

RESUMO

The deficiency of the enzyme glutaryl-CoA dehydrogenase leads to predominant accumulation of glutaric acid (GA) in the organism and is known as glutaric acidemia type I (GA1). Despite the mechanisms of brain damage involved in GA1 are not fully understood, oxidative stress may be involved in this process. Treatment is based on protein/lysine (Lys) restriction and l-carnitine (L-car) supplementation. L-car was recently shown to have an important antioxidant role. A knockout mice model (Gcdh-/-) submitted to a dietary overload of Lys was developed to better understand the GA1 pathogenesis. In this study, we evaluated L-car and glutarylcarnitine levels, the lipid and protein damage, reactive oxygen species (ROS) production and antioxidant enzymes activities in striatum of Gcdh-/- and wild-type (WT) mice. We also determined the effect of the L-car treatment on these parameters. Thirty-day-old Gcdh-/- and WT mice were fed a normal chow (0.9% Lys) or submitted to a high Lys diet (4.7%) for 72 h. Additionally, these animals were administered with three intraperitoneal injections of saline or L-car in different times. Gcdh-/- mice were deficient in L-car and presented a higher glutarylcarnitine levels. They also presented lipid and protein damage, an increased ROS production and altered antioxidant enzymes compared to WT mice. Additionally, mice exposed to Lys overload presented higher alterations in these parameters than mice under normal diet, which were significantly decreased or normalized in those receiving L-car. Thus, we demonstrated a new beneficial effect of the L-car treatment attenuating or abolishing the oxidative stress process in Gcdh-/- mice.

3.
Int J Dev Neurosci ; 2019 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-31125684

RESUMO

Glutaric acidemia type I (GA I) is an inherited neurometabolic disease caused by deficient activity of the mitochondrial enzyme glutaryl-CoA dehydrogenase (GCDH), resulting in predominant accumulation of glutaric and 3-hydroxyglutaric acids derived from lysine (Lys), hydroxylysine, and tryptophan catabolism. GA I patients usually present progressive cortical leukodystrophy and frequently develop acute striatal degeneration during encephalopathic crises during the first three years of life. The pathophysiology of the neurodegeneration observed in GA I is still partly known, although the development of the genetic mice model of GA I (Gcdh-/-) has contributed to clarify potential underlying mechanisms involved in brain damage in this disease. In this review we will summarize the knowledge acquired from studies using this animal model indicating that disruption of redox homeostasis, glutamatergic neurotransmission and bioenergetics, as well as vascular alterations, blood-brain barrier breakage and altered myelination underlie the cortical and striatum abnormalities and white matter changes observed in GA I patients. Elucidation of these pathomechanisms potentially offers new standpoints for the development of novel therapeutic strategies for this disease.

4.
Neurochem Int ; 129: 104467, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31121257

RESUMO

Glutaric acidemia type I (GA I) is a neurometabolic disorder of lysine (Lys) catabolism caused by glutaryl-CoA dehydrogenase (GCDH) deficiency. Patients are susceptible to develop acute striatum degeneration during catabolic stress situations whose underlying mechanisms are not fully established. Thus, in the present work we investigated the effects of a single intrastriatal Lys administration (1.5-4 µmol) to 30-day-old wild type (WT) and GCDH deficient (Gcdh-/-) mice on brain morphology, neuronal injury, astrocyte reactivity and myelin structure, as well as signaling pathways of redox homeostasis. We observed a marked vacuolation/edema in striatum and at higher doses also in cerebral cortex of Gcdh-/-, but not of WT mice. Lys also provoked a reduction of NeuN and synaptophysin, as well as an increase of astrocytic GFAP, in the striatum of Gcdh-/- mice, indicating neuronal loss and astrocyte reactivity. Furthermore, we verified an increase of Nrf2 and NF-κB expression in the nuclear fraction, and a decrease of heme oxygenase-1 (HO-1) content in the striatum of Lys-injected Gcdh-/- mice, implying disruption of redox homeostasis. Finally, it was found that Lys provoked alterations of myelin structure reflected by decreased myelin basic protein (MBP) in the cerebral cortex of Gcdh-/- mice. Taken together, the present data demonstrate neuronal loss, gliosis, altered redox homeostasis and demyelination caused by acute Lys overload in brain of Gcdh-/- mice, supporting the hypothesis that increased brain concentrations of glutaric and 3-hydroxyglutaric acids formed from Lys may be responsible for the acute brain degeneration observed in GA I patients during episodes of metabolic decompensation.

5.
Mol Cell Biochem ; 458(1-2): 99-112, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31032535

RESUMO

Maleic acid (MA), which has been reported to be highly excreted in propionic acidemia (PAcidemia), was demonstrated to cause nephropathy by bioenergetics impairment and oxidative stress, but the effects on kidney mitochondrial respiration has not yet been properly investigated. Therefore, the present study investigated the effects of MA (0.05-5 mM), as well as of propionic (PA) and 3-hydroxypropionic (3OHPA) acids (5 mM) that accumulate in PAcidemia, on mitochondrial respiration supported by glutamate, glutamate plus malate or succinate in mitochondrial fractions and homogenates from rat kidney, as well as in permeabilized kidney cells. MA markedly decreased oxygen consumption in state 3 (ADP-stimulated) and uncoupled (CCCP-stimulated) respiration in glutamate and glutamate plus malate-respiring mitochondria, with less prominent effects when using succinate. We also found that PA significantly decreased state 3 and uncoupled respiration in glutamate- and glutamate plus malate-supported mitochondria, whereas 3OHPA provoked milder or no changes. Furthermore, glutamate dehydrogenase and α-ketoglutarate dehydrogenase activities necessary for glutamate oxidation were significantly inhibited by MA in a dose-dependent and competitive fashion. The MA-induced decrease of state 3 and uncoupled respiration found in mitochondrial fractions were also observed in homogenates and permeabilized renal cells that better mimic the in vivo cellular milieu. Taken together, our data indicate that MA, and PA to a lesser extent, disturb mitochondrial-oxidative metabolism in the kidney with the involvement of critical enzymes for glutamate oxidation. It is postulated that our present findings may be possibly involved in the chronic renal failure observed in patients with PAcidemia.


Assuntos
Glutamato Desidrogenase/metabolismo , Ácido Glutâmico/metabolismo , Complexo Cetoglutarato Desidrogenase/metabolismo , Rim/metabolismo , Maleatos/metabolismo , Mitocôndrias/metabolismo , Animais , Masculino , Oxirredução , Ratos , Ratos Wistar
6.
Lung ; 197(2): 139-146, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30623243

RESUMO

INTRODUCTION: Serum vascular endothelial growth factor-D (VEGF-D) is a lymphangiogenic growth factor that is considered a valuable tool in the diagnosis of lymphangioleiomyomatosis (LAM). Previous studies have reported a wide variability in VEGF-D serum levels in LAM patients and it seems to be associated with pulmonary impairment and lymphatic involvement. METHODS: We conducted a cross-sectional study from 2009 to 2017 that evaluated VEGF-D serum levels in a cohort of LAM patients who were never treated with mTOR inhibitors and compared them to healthy age-matched volunteers. Clinical and functional parameters were assessed and correlated with their respective serum VEGF-D levels. RESULTS: One hundred and four patients were included in the analysis. Serum VEGF-D levels were higher in LAM patients compared to healthy controls: 796 (404-1588) versus 162 (117-232) pg/mL, respectively (p < 0.001). Patients with tuberous sclerosis complex-LAM, TSC-LAM (20%), had higher levels of VEGF-D when compared to patients with sporadic LAM (80%) [1005 (641-2732) vs. 772 (370-1383), p = 0.05]. Serum VEGF-D levels were weakly correlated with DLCO (r = - 0.26, p = 0.001) and lymphatic involvement was more frequent in those with serum VEGF-D levels equal or above 800 pg/mL (35% vs. 13%, p = 0.02). CONCLUSIONS: In LAM, serum VEGF-D is weakly associated with lung function impairment and strongly associated with lymphatic involvement. VEGF-D is validated for use in Brazilian patients with LAM whose characteristics must be accounted for when evaluating their serum VEGF-D levels.

7.
Rev. bras. ter. intensiva ; 30(4): 405-413, out.-dez. 2018. tab, graf
Artigo em Português | LILACS-Express | ID: biblio-977985

RESUMO

RESUMO Objetivo: Avaliar a prevalência de incapacidades físicas, cognitivas e psiquiátricas, fatores associados e sua relação com qualidade de vida em pacientes sobreviventes de internação em unidades de terapia intensiva brasileiras. Métodos: Um estudo de coorte prospectivo multicêntrico está sendo conduzido em dez unidades de terapia intensiva adulto clínico-cirúrgicas representativas das cinco regiões geopolíticas do Brasil. Pacientes com idade ≥ 18 anos que receberam alta das unidades de terapia intensiva participantes e permaneceram internados na unidade de terapia intensiva por 72 horas ou mais, nos casos de internação clínica ou cirúrgica de urgência, e por 120 horas ou mais, nos casos de internação cirúrgica eletiva, serão incluídos de forma consecutiva. Estes pacientes serão seguidos por 1 ano, por meio de entrevistas telefônicas estruturadas 3, 6 e 12 meses pós-alta da unidade de terapia intensiva. Dependência funcional, disfunção cognitiva, sintomas de ansiedade e depressão, sintomas de estresse pós-traumático, qualidade de vida relacionada à saúde, re-hospitalizações e mortalidade em longo prazo serão avaliados como desfechos. Discussão: O presente estudo tem o potencial de contribuir para o conhecimento a respeito da prevalência e dos fatores associados à síndrome pós-cuidados intensivos na população de pacientes adultos sobreviventes de internação em unidades de terapia intensiva brasileiras. Ademais, a associação entre síndrome pós-cuidados intensivos e qualidade de vida relacionada à saúde poderá ser estabelecida.


ABSTRACT Objective: To establish the prevalence of physical, cognitive and psychiatric disabilities, associated factors and their relationship with the qualities of life of intensive care survivors in Brazil. Methods: A prospective multicenter cohort study is currently being conducted at 10 adult medical-surgical intensive care units representative of the 5 Brazilian geopolitical regions. Patients aged ≥ 18 years who are discharged from the participating intensive care units and stay 72 hours or more in the intensive care unit for medical or emergency surgery admissions or 120 hours or more for elective surgery admissions are consecutively included. Patients are followed up for a period of one year by means of structured telephone interviews conducted at 3, 6 and 12 months after discharge from the intensive care unit. The outcomes are functional dependence, cognitive dysfunction, anxiety and depression symptoms, posttraumatic stress symptoms, health-related quality of life, rehospitalization and long-term mortality. Discussion: The present study has the potential to contribute to current knowledge of the prevalence and factors associated with postintensive care syndrome among adult intensive care survivors in Brazil. In addition, an association might be established between postintensive care syndrome and health-related quality of life.

9.
Mitochondrion ; 2018 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-30399433

RESUMO

We report here the effects of hydrogen sulfide (sulfide), that accumulates in ETHE1 deficiency, in rat cerebellum. Sulfide impaired electron transfer and oxidative phosphorylation. Sulfide also induced mitochondrial swelling, and decreased ΔΨm and calcium retention capacity in cerebellum mitochondria, which were prevented by cyclosporine A (CsA) plus ADP, and ruthenium red, suggesting mitochondrial permeability transition (mPT) induction. Melatonin (MEL) and N-ethylmaleimide also prevented sulfide-induced alterations. Prevention of sulfide-induced decrease of ΔΨm and viability by CsA and MEL was further verified in cerebellum neurons. The data suggest that sulfide induces mPT pore opening via thiol modification and ROS generation.

10.
J Cell Biochem ; 119(9): 7678-7686, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29923625

RESUMO

Patients affected by long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency predominantly present severe liver and cardiac dysfunction, as well as neurological symptoms during metabolic crises, whose pathogenesis is still poorly known. In this study, we demonstrate for the first time that pathological concentrations of 3-hydroxypalmitic acid (3HPA), the long-chain hydroxyl fatty acid (LCHFA) that most accumulates in LCHAD deficiency, significantly decreased adenosine triphosphate-linked and uncoupled mitochondrial respiration in intact cell systems consisting of heart fibers, cardiomyocytes, and hepatocytes, but less intense in diced forebrain. 3HPA also significantly reduced mitochondrial Ca2+ retention capacity and membrane potential in Ca2+ -loaded mitochondria more markedly in the heart and the liver, with mild or no effects in the brain, supporting a higher susceptibility of the heart and the liver to the toxic effects of this fatty acid. It is postulated that disruption of mitochondrial energy and Ca2+ homeostasis caused by the accumulation of LCHFA may contribute toward the severe cardiac and hepatic clinical manifestations observed in the affected patients.

11.
BMJ Open ; 8(4): e021193, 2018 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-29654049

RESUMO

INTRODUCTION: Flexible intensive care unit (ICU) visiting hours have been proposed as a means to improve patient-centred and family-centred care. However, randomised trials evaluating the effects of flexible family visitation models (FFVMs) are scarce. This study aims to compare the effectiveness and safety of an FFVM versus a restrictive family visitation model (RFVM) on delirium prevention among ICU patients, as well as to analyse its potential effects on family members and ICU professionals. METHODS AND ANALYSIS: A cluster-randomised crossover trial involving adult ICU patients, family members and ICU professionals will be conducted. Forty medical-surgical Brazilian ICUs with RFVMs (<4.5 hours/day) will be randomly assigned to either an RFVM (visits according to local policies) or an FFVM (visitation during 12 consecutive hours per day) group at a 1:1 ratio. After enrolment and follow-up of 25 patients, each ICU will be switched over to the other visitation model, until 25 more patients per site are enrolled and followed. The primary outcome will be the cumulative incidence of delirium among ICU patients, measured twice a day using the Confusion Assessment Method for the ICU. Secondary outcome measures will include daily hazard of delirium, ventilator-free days, any ICU-acquired infections, ICU length of stay and hospital mortality among the patients; symptoms of anxiety and depression and satisfaction among the family members; and prevalence of burnout symptoms among the ICU professionals. Tertiary outcomes will include need for antipsychotic agents and/or mechanical restraints, coma-free days, unplanned loss of invasive devices and ICU-acquired pneumonia, urinary tract infection or bloodstream infection among the patients; self-perception of involvement in patient care among the family members; and satisfaction among the ICU professionals. ETHICS AND DISSEMINATION: The study protocol has been approved by the research ethics committee of all participant institutions. We aim to disseminate the findings through conferences and peer-reviewed journals. TRIAL REGISTRATION: NCT02932358.

12.
Neurotox Res ; 33(3): 681-692, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29411290

RESUMO

Tissue accumulation of L-2-hydroxyglutaric acid (L-2-HG) is the biochemical hallmark of L-2-hydroxyglutaric aciduria (L-2-HGA), a rare neurometabolic inherited disease characterized by neurological symptoms and brain white matter abnormalities whose pathogenesis is not yet well established. L-2-HG was intracerebrally administered to rat pups at postnatal day 1 (P1) to induce a rise of L-2-HG levels in the central nervous system (CNS). Thereafter, we investigated whether L-2-HG in vivo administration could disturb redox homeostasis and induce brain histopathological alterations in the cerebral cortex and striatum of neonatal rats. L-2-HG markedly induced the generation of reactive oxygen species (increase of 2',7'-dichloroflurescein-DCFH-oxidation), lipid peroxidation (increase of malondialdehyde concentrations), and protein oxidation (increase of carbonyl formation and decrease of sulfhydryl content), besides decreasing the antioxidant defenses (reduced glutathione-GSH) and sulfhydryl content in the cerebral cortex. Alterations of the activities of various antioxidant enzymes were also observed in the cerebral cortex and striatum following L-2-HG administration. Furthermore, L-2-HG-induced lipid peroxidation and GSH decrease in the cerebral cortex were prevented by the antioxidant melatonin and by the classical antagonist of NMDA glutamate receptor MK-801, suggesting the involvement of reactive species and of overstimulation of NMDA receptor in these effects. Finally, L-2-HG provoked significant vacuolation and edema particularly in the cerebral cortex with less intense alterations in the striatum that were possibly associated with the unbalanced redox homeostasis caused by this metabolite. Taken together, it is presumed that these pathomechanisms may underlie the neurological symptoms and brain abnormalities observed in the affected patients.

13.
FEBS J ; 285(8): 1437-1455, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29476646

RESUMO

We studied the effects of the major long-chain fatty acids accumulating in very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency, namely cis-5-tetradecenoic acid (Cis-5) and myristic acid (Myr), on important mitochondrial functions in isolated mitochondria from cardiac fibers and cardiomyocytes of juvenile rats. Cis-5 and Myr at pathological concentrations markedly reduced mitochondrial membrane potential (ΔΨm ), matrix NAD(P)H pool, Ca2+ retention capacity, ADP- (state 3) and carbonyl cyanide 3-chlorophenyl hydrazine-stimulated (uncoupled) respiration, and ATP generation. By contrast, these fatty acids increased resting (state 4) respiration (uncoupling effect) with the involvement of the adenine nucleotide translocator because carboxyatractyloside significantly attenuated the increased state 4 respiration provoked by Cis-5 and Myr. Furthermore, the classical inhibitors of mitochondrial permeability transition (MPT) pore cyclosporin A plus ADP, as well as the Ca2+ uptake blocker ruthenium red, fully prevented the Cis-5- and Myr-induced decrease in ΔΨm in Ca2+ -loaded mitochondria, suggesting, respectively, the induction of MPT pore opening and the contribution of Ca2+ toward these effects. The findings of the present study indicate that the major long-chain fatty acids that accumulate in VLCAD deficiency disrupt mitochondrial bioenergetics and Ca2+ homeostasis, acting as uncouplers and metabolic inhibitors of oxidative phosphorylation, as well as inducers of MPT pore opening, in the heart at pathological relevant concentrations. It is therefore presumed that a disturbance of bioenergetics and Ca2+ homeostasis may contribute to the cardiac manifestations observed in VLCAD deficiency.

14.
Mol Neurobiol ; 55(7): 5868-5878, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29101646

RESUMO

S-Adenosylmethionine (AdoMet) concentrations are highly elevated in tissues and biological fluids of patients affected by S-adenosylhomocysteine hydrolase deficiency, who are clinically characterized by cerebral symptoms whose pathogenesis is still unknown. In the present work, we investigated the effects of AdoMet on redox homeostasis and on the activity of Na+, K+-ATPase in the cerebral cortex of young rats. AdoMet caused lipid peroxidation (increase of malondialdehyde concentrations) and protein oxidation (increase of carbonyl formation and decrease of sulfhydryl content). AdoMet also reduced the antioxidant defenses (reduced glutathione, GSH) and Na+, K+-ATPase activity. Furthermore, AdoMet-induced lipid peroxidation was fully prevented by the antioxidants trolox, melatonin, and resveratrol, and the decrease of GSH concentrations was abolished by trolox, suggesting the involvement of reactive oxygen species in these effects. In this context, AdoMet induced reactive oxygen (increase of 2',7'-dichloroflurescein-DCFH oxidation) but not nitrogen (nitrate and nitrite levels) species generation. Finally, the decrease of Na+, K+-ATPase activity provoked by AdoMet was totally prevented by trolox, implying a possible oxidation of cysteine groups of the enzyme that are critical for its function and highly susceptible to oxidative attack. It is also noted that adenosine and methionine did not alter the parameters evaluated, suggesting selective effects of AdoMet. Our data strongly indicate that disturbance of redox homeostasis caused by a major metabolite (AdoMet) accumulating in S-adenosylhomocysteine hydrolase deficiency may represent a deleterious mechanism of brain damage in this disease. Finally, reduction of Na+, K+-ATPase activity provoked by AdoMet may lead to impaired neurotransmission, but disturbance of this system should be better clarified in future studies.

15.
Neurotox Res ; 33(3): 593-606, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29235064

RESUMO

Glutaric acidemia type I (GA I) is an inherited neurometabolic disorder caused by a severe deficiency of the mitochondrial glutaryl-CoA dehydrogenase (GCDH) activity. Patients usually present progressive cortical leukodystrophy and commonly develop acute bilateral striatal degeneration mainly during infections that markedly worse their prognosis. A role for quinolinic acid (QA), a key metabolite of the kynurenine pathway, which is activated during inflammatory processes, on the pathogenesis of the acute striatum degeneration occurring in GA I was proposed but so far has not yet been evaluated. Therefore, we investigated whether an acute intrastriatal administration of quinolinic acid (QA) could induce histopathological alterations in the striatum of 30-day-old wild-type (WT) and GCDH knockout (Gcdh-/-) mice. Striatum morphology was evaluated by hematoxylin and eosin, T lymphocyte presence (CD3), and glial activation (GFAP and S100ß) by immunohistochemistry and 3-nitrotyrosine (YNO2) by immunofluorescence. QA provoked extensive vacuolation, edema, and especially lymphocyte infiltration in the striatum of Gcdh-/-. QA also enhanced CD3 staining and the number of YNO2 positive cells in Gcdh-/- mice, relatively to WT, indicating T lymphocyte infiltration and nitrosative stress, respectively. QA-treated WT mice also showed an increase of GFAP and S100ß staining, which is indicative of reactive astrogliosis, whereas the levels of these astrocytic proteins were not changed in Gcdh-/- QA-injected mice. The present data indicate that QA significantly contributes to the histopathological changes observed in the striatum of Gcdh-/- mice.

16.
Rev Bras Ter Intensiva ; 30(4): 405-413, 2018 Oct-Dec.
Artigo em Português, Inglês | MEDLINE | ID: mdl-30652780

RESUMO

OBJECTIVE: To establish the prevalence of physical, cognitive and psychiatric disabilities, associated factors and their relationship with the qualities of life of intensive care survivors in Brazil. METHODS: A prospective multicenter cohort study is currently being conducted at 10 adult medical-surgical intensive care units representative of the 5 Brazilian geopolitical regions. Patients aged ≥ 18 years who are discharged from the participating intensive care units and stay 72 hours or more in the intensive care unit for medical or emergency surgery admissions or 120 hours or more for elective surgery admissions are consecutively included. Patients are followed up for a period of one year by means of structured telephone interviews conducted at 3, 6 and 12 months after discharge from the intensive care unit. The outcomes are functional dependence, cognitive dysfunction, anxiety and depression symptoms, posttraumatic stress symptoms, health-related quality of life, rehospitalization and long-term mortality. DISCUSSION: The present study has the potential to contribute to current knowledge of the prevalence and factors associated with postintensive care syndrome among adult intensive care survivors in Brazil. In addition, an association might be established between postintensive care syndrome and health-related quality of life.


Assuntos
Unidades de Terapia Intensiva , Qualidade de Vida , Sobreviventes/psicologia , Ansiedade/epidemiologia , Brasil , Disfunção Cognitiva/epidemiologia , Estudos de Coortes , Cuidados Críticos , Depressão/epidemiologia , Seguimentos , Humanos , Alta do Paciente , Prevalência , Estudos Prospectivos , Fatores de Tempo
17.
Epilepsia ; 58(10): 1771-1781, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28762469

RESUMO

OBJECTIVES: Glutaric acidemia type I (GA-I) is an inherited neurometabolic disorder caused by deficiency of glutaryl-CoA dehydrogenase (GCDH) and characterized by increased levels of glutaric, 3-OH-glutaric, and glutaconic acids in the brain parenchyma. The increment of these organic acids inhibits glutamate decarboxylase (GAD) and consequently lowers the γ-aminobutyric acid (GABA) synthesis. Untreated patients exhibit severe neurologic deficits during development, including epilepsy, especially following an acute encephalopathy outbreak. In this work, we evaluated the role of the GABAergic system on epileptogenesis in GA-I using the Gcdh-/- mice exposed to a high lysine diet (Gcdh-/- -Lys). METHODS: Spontaneous recurrent seizures (SRS), seizure susceptibility, and changes in brain oscillations were evaluated by video-electroencephalography (EEG). Cortical GABAergic synaptic transmission was evaluated using electrophysiologic and neurochemical approaches. RESULTS: SRS were observed in 72% of Gcdh-/- -Lys mice, whereas no seizures were detected in age-matched controls (Gcdh+/+ or Gcdh-/- receiving normal diet). The severity and number of PTZ-induced seizures were higher in Gcdh-/- -Lys mice. EEG spectral analysis showed a significant decrease in theta and gamma oscillations and predominant delta waves in Gcdh-/- -Lys mice, associated with increased EEG left index. Analysis of cortical synaptosomes revealed a significantly increased percentage of glutamate release and decreased GABA release in Gcdh-/- -Lys mice that were associated with a decrease in cortical GAD immunocontent and activity and confirmed by reduced frequency of inhibitory events in cortical pyramidal cells. SIGNIFICANCE: Using an experimental model with a phenotype similar to that of GA-I in humans-the Gcdh-/- mice under high lysine diet (Gcdh-/- -Lys)-we provide evidence that a reduction in cortical inhibition of Gcdh-/- -Lys mice, probably induced by GAD dysfunction, leads to hyperexcitability and increased slow oscillations associated with neurologic abnormalities in GA-I. Our findings offer a new perspective on the pathophysiology of brain damage in GA-I.


Assuntos
Erros Inatos do Metabolismo dos Aminoácidos/genética , Encefalopatias Metabólicas/genética , Encéfalo/efeitos dos fármacos , Epilepsia/genética , Glutaril-CoA Desidrogenase/deficiência , Glutaril-CoA Desidrogenase/genética , Ácido gama-Aminobutírico/efeitos dos fármacos , Erros Inatos do Metabolismo dos Aminoácidos/metabolismo , Animais , Western Blotting , Encefalopatias Metabólicas/metabolismo , Cromatografia Líquida de Alta Pressão , Epilepsia/metabolismo , Antagonistas GABAérgicos/farmacologia , Glutamato Descarboxilase , Ácido Glutâmico/efeitos dos fármacos , Ácido Glutâmico/metabolismo , Glutaril-CoA Desidrogenase/metabolismo , Camundongos , Camundongos Knockout , Pentilenotetrazol/farmacologia , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/metabolismo , Ácido gama-Aminobutírico/metabolismo
18.
Biochim Biophys Acta Mol Basis Dis ; 1863(9): 2192-2201, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28624490

RESUMO

Hydrogen sulfide (sulfide) accumulates at high levels in brain of patients with ethylmalonic encephalopathy (EE). In the present study, we evaluated whether sulfide could disturb energy and redox homeostasis, and induce mitochondrial permeability transition (mPT) pore opening in rat brain aiming to better clarify the neuropathophysiology of EE. Sulfide decreased the activities of citrate synthase and aconitase in rat cerebral cortex mitochondria, and of creatine kinase (CK) in rat cerebral cortex, striatum and hippocampus supernatants. Glutathione prevented sulfide-induced CK activity decrease in the cerebral cortex. Sulfide also diminished mitochondrial respiration in cerebral cortex homogenates, and dissipated mitochondrial membrane potential (ΔΨm) and induced swelling in the presence of calcium in brain mitochondria. Alterations in ΔΨm and swelling caused by sulfide were prevented by the combination of ADP and cyclosporine A, and by ruthenium red, indicating the involvement of mPT in these effects. Furthermore, sulfide increased the levels of malondialdehyde in cerebral cortex supernatants, which was prevented by resveratrol and attenuated by glutathione, and of thiol groups in a medium devoid of brain samples. Finally, we verified that sulfide did not alter cell viability and DCFH oxidation in cerebral cortex slices, primary cortical astrocyte cultures and SH-SY5Y cells. Our data provide evidence that bioenergetics disturbance and lipid peroxidation along with mPT pore opening are involved in the pathophysiology of brain damage observed in EE.


Assuntos
Encefalopatias Metabólicas Congênitas/metabolismo , Córtex Cerebral/metabolismo , Metabolismo Energético/efeitos dos fármacos , Sulfeto de Hidrogênio/efeitos adversos , Peroxidação de Lipídeos/efeitos dos fármacos , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Púrpura/metabolismo , Animais , Encefalopatias Metabólicas Congênitas/induzido quimicamente , Encefalopatias Metabólicas Congênitas/patologia , Linhagem Celular Tumoral , Córtex Cerebral/patologia , Sulfeto de Hidrogênio/farmacologia , Masculino , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Púrpura/induzido quimicamente , Púrpura/patologia , Ratos , Ratos Wistar
19.
Neurotox Res ; 32(2): 276-290, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28429309

RESUMO

Tissue accumulation of α-ketoadipic (KAA) and α-aminoadipic (AAA) acids is the biochemical hallmark of α-ketoadipic aciduria. This inborn error of metabolism is currently considered a biochemical phenotype with uncertain clinical significance. Considering that KAA and AAA are structurally similar to α-ketoglutarate and glutamate, respectively, we investigated the in vitro effects of these compounds on glutamatergic neurotransmission in the brain of adolescent rats. Bioenergetics and redox homeostasis were also investigated because they represent fundamental systems for brain development and functioning. We first observed that AAA significantly decreased glutamate uptake, whereas glutamate dehydrogenase activity was markedly inhibited by KAA in a competitive fashion. In addition, AAA and more markedly KAA induced generation of reactive oxygen and nitrogen species (increase of 2',7'-dichloroflurescein (DCFH) oxidation and nitrite/nitrate levels), lipid peroxidation (increase of malondialdehyde concentrations), and protein oxidation (increase of carbonyl formation and decrease of sulfhydryl content), besides decreasing the antioxidant defenses (reduced glutathione (GSH)) and aconitase activity. Furthermore, KAA-induced lipid peroxidation and GSH decrease were prevented by the antioxidants α-tocopherol, melatonin, and resveratrol, suggesting the involvement of reactive species in these effects. Noteworthy, the classical inhibitor of NMDA glutamate receptors MK-801 was not able to prevent KAA-induced and AAA-induced oxidative stress, determined by DCFH oxidation and GSH levels, making unlikely a secondary induction of oxidative stress through overstimulation of glutamate receptors. In contrast, KAA and AAA did not significantly change brain bioenergetic parameters. We speculate that disturbance of glutamatergic neurotransmission and redox homeostasis by KAA and AAA may play a role in those cases of α-ketoadipic aciduria that display neurological symptoms.


Assuntos
Ácido 2-Aminoadípico/farmacologia , Adipatos/farmacologia , Córtex Cerebral/efeitos dos fármacos , Antagonistas de Aminoácidos Excitatórios/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Adenosina Trifosfatases/metabolismo , Animais , Membrana Celular/efeitos dos fármacos , Glutamato Desidrogenase/metabolismo , Glutamato-Amônia Ligase/metabolismo , Ácido Glutâmico/metabolismo , Homeostase/efeitos dos fármacos , Fígado/efeitos dos fármacos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Complexos Multienzimáticos/metabolismo , Carbonilação Proteica/efeitos dos fármacos , Ratos , Sinapses/efeitos dos fármacos , Trítio/metabolismo
20.
Neurochem Int ; 108: 133-145, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28284974

RESUMO

Mevalonic aciduria (MVA) is caused by severe deficiency of mevalonic kinase activity leading to tissue accumulation and high urinary excretion of mevalonic acid (MA) and mevalonolactone (ML). Patients usually present severe neurologic symptoms whose pathophysiology is poorly known. Here, we tested the hypothesis that the major accumulating metabolites are toxic by investigating the in vitro effects of MA and ML on important mitochondrial functions in rat brain and liver mitochondria. ML, but not MA, markedly decreased mitochondrial membrane potential (ΔΨm), NAD(P)H content and the capacity to retain Ca2+ in the brain, besides inducing mitochondrial swelling. These biochemical alterations were totally prevented by the classical inhibitors of mitochondrial permeability transition (MPT) cyclosporine A and ADP, as well as by ruthenium red in Ca2+-loaded mitochondria, indicating the involvement of MPT and an important role for mitochondrial Ca2+ in these effects. ML also induced lipid peroxidation and markedly inhibited aconitase activity, an enzyme that is highly susceptible to free radical attack, in brain mitochondrial fractions, indicating that lipid and protein oxidative damage may underlie some of ML-induced deleterious effects including MTP induction. In contrast, ML and MA did not compromise oxidative phosphorylation in the brain and all mitochondrial functions evaluated in the liver, evidencing a selective toxicity of ML towards the central nervous system. Our present study provides for the first time evidence that ML impairs essential brain mitochondrial functions with the involvement of MPT pore opening. It is therefore presumed that disturbance of brain mitochondrial homeostasis possibly contributes to the neurologic symptoms in MVA.


Assuntos
Potencial da Membrana Mitocondrial/fisiologia , Deficiência de Mevalonato Quinase/induzido quimicamente , Deficiência de Mevalonato Quinase/metabolismo , Ácido Mevalônico/análogos & derivados , Mitocôndrias/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Ácido Mevalônico/toxicidade , Mitocôndrias/efeitos dos fármacos , Proteínas de Transporte da Membrana Mitocondrial/agonistas , Ratos , Ratos Wistar
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