RESUMO
Phenylketonuria (PKU) is the most common inherited metabolic disorders caused by severe deficiency or absence of phenylalanine hydroxylase activity that converts phenylalanine (Phe) to tyrosine. PKU patients were treated with a Phe restricted diet supplemented with a special formula containing l-carnitine (L-car), well-known antioxidant compound. The lack of treatment can cause neurological and cognitive impairment, as severe mental retardation, neuronal cell loss and synaptic density reduction. Although Phe has been widely demonstrated to be involved in PKU neurotoxicity, the mechanisms responsible for the CNS injury are still not fully known. In this work, we evaluated markers of neurodegeneration, namely BDNF (brain-derived neurotrophic factor), PAI-1 total (Plasminogen activator inhibitor-1 total), Cathepsin D, PDGF AB/BB (platelet-derived growth factor), and NCAM (neuronal adhesion molecule) in plasma of PKU patients at early and late diagnosis and under treatment. We found decreased Phe levels and increased L-car concentrations in PKU patients treated with L-car compared to the other groups, indicating that the proposed treatment was effective. Furthermore, we found increased BDNF levels in the patients under treatment compared to patients at early diagnosis, and a positive correlation between BDNF and L-car and a negative correlation between BDNF and Phe. Our results may indicate that in PKU patients treated with L-car there is an attempt to adjust neuronal plasticity and recover the damage suffered, reflecting a compensatory response to brain injury.
Assuntos
Carnitina , Fenilcetonúrias , Humanos , Fator Neurotrófico Derivado do Encéfalo , Fenilcetonúrias/tratamento farmacológico , Suplementos Nutricionais , Antioxidantes , Fenilalanina , BecaplerminaRESUMO
Phenylketonuria (PKU) was the first genetic disease to have an effective therapy, which consists of phenylalanine intake restriction. However, there are patients who do not adhere to treatment and/or are not submitted to neonatal screening. PKU patients present L-carnitine (L-car) deficiency, compound that has demonstrated an antioxidant and anti-inflammatory role in metabolic diseases. This study evaluated the effect caused by exposure time to high Phe levels in PKU patients at early and late diagnosis, through pro- and anti-inflammatory cytokines, as well as the L-car effect in patients under treatment. It was observed that there was a decrease in phenylalanine levels in treated patients compared to patients at diagnosis, and an increase in L-car levels in the patients under treatment. Inverse correlation between Phe versus L-car and nitrate plus nitrite versus L-car in PKU patients was also showed. We found increased proinflammatory cytokines levels: interleukin (IL)-1ß, interferons (IFN)-gamma, IL-2, tumor necrosis factor (TNF)-alpha, IL-8 and IL-6 in the patients at late diagnosis compared to controls, and IL-8 in the patients at early diagnosis and treatment compared to controls. Increased IL-2, TNF-alpha, IL-6 levels in the patients at late diagnosis compared to early diagnosis were shown, and reduced IL-6 levels in the treated patients compared to patients at late diagnosis. Moreover, it verified a negative correlation between IFN-gamma and L-car in treated patients. Otherwise, it was observed that there were increased IL-4 levels in the patients at late diagnosis compared to early diagnosis, and reduction in treated patients compared to late diagnosed patients. In urine, there was an increase in 8-isoprostane levels in the patients at diagnosis compared to controls and a decrease in oxidized guanine species in the treated patients compared to the diagnosed patients. Our results demonstrate for the first time in literature that time exposure to high Phe concentrations generates a proinflammatory status, especially in PKU patients with late diagnosis. A pro-oxidant status was verified in not treated PKU patients. Our results demonstrate the importance of early diagnosis and prompt start of treatment, in addition to the importance of L-car supplementation, which can improve cellular defense against inflammation and oxidative damage in PKU patients.
Assuntos
Citocinas , Fenilcetonúrias , Recém-Nascido , Humanos , Fenilalanina , Diagnóstico Tardio , Interleucina-2 , Interleucina-6 , Interleucina-8 , Carnitina/farmacologia , Fenilcetonúrias/diagnóstico , Fenilcetonúrias/tratamento farmacológico , Fenilcetonúrias/urina , Fator de Necrose Tumoral alfaRESUMO
Maple syrup urine disease (MSUD) is a genetic disorder that leads the accumulation of branched-chain amino acids (BCAA) leucine (Leu), isoleucine, valine and metabolites. The symptomatology includes psychomotor delay and mental retardation. MSUD therapy comprises a lifelong protein strict diet with low BCAA levels and is well established that high concentrations of Leu and/or its ketoacid are associated with neurological symptoms. Recently, it was demonstrated that the phenylbutyrate (PBA) have the ability to decrease BCAA concentrations. This work aimed the development of lipid-based nanoparticles loaded with PBA, capable of targeting to the central nervous system in order to verify its action mechanisms on oxidative stress and cell death in brain of rats subjected to a MSUD chronic model. PBA-loaded nanoparticles treatment was effective in significantly decreasing BCAA concentration in plasma and Leu in the cerebral cortex of MSUD animals. Furthermore, PBA modulate the activity of catalase, superoxide dismutase, glutathione peroxidase and glutathione reductase enzymes, as well as preventing the oxidative damage to lipid membranes and proteins. PBA was also able to decrease the glial fibrillary acidic protein concentrations and partially decreased the reactive species production and caspase-3 activity in MSUD rats. Taken together, the data indicate that the PBA-loaded nanoparticles could be an efficient adjuvant in the MSUD therapy, protecting against oxidative brain damage and neuroinflammation.
Assuntos
Aminoácidos de Cadeia Ramificada/sangue , Córtex Cerebral/efeitos dos fármacos , Doença da Urina de Xarope de Bordo/metabolismo , Nanopartículas/administração & dosagem , Estresse Oxidativo/efeitos dos fármacos , Fenilbutiratos/administração & dosagem , Animais , Catalase/metabolismo , Córtex Cerebral/metabolismo , Glutationa Peroxidase/metabolismo , Doença da Urina de Xarope de Bordo/sangue , Doença da Urina de Xarope de Bordo/induzido quimicamente , Ratos , Ratos Wistar , Superóxido Dismutase/metabolismoRESUMO
Several studies have examined neonatal diabetes, a rare disease characterized by hyperglycemia and low insulin levels that is usually diagnosed in the first 6 month of life. Recently, the effects of diabetes on the brain have received considerable attention. In addition, hyperglycemia may perturb brain function and might be associated with neuronal death in adult rats. However, few studies have investigated the damaging effects of neonatal hyperglycemia on the rat brain during central nervous system (CNS) development, particularly the mechanisms involved in the disease. Thus, in the present work, we investigated whether neonatal hyperglycemia induced by streptozotocin (STZ) promoted cell death and altered the levels of proteins involved in survival/death pathways in the rat brain. Cell death was assessed using FluoroJade C (FJC) staining and the expression of the p38 mitogen-activated protein kinase (p38), phosphorylated-c-Jun amino-terminal kinase (p-JNK), c-Jun amino-terminal kinase (JNK), protein kinase B (Akt), phosphorylated-protein kinase B (p-Akt), glycogen synthase kinase-3ß (Gsk3ß), B-cell lymphoma 2 (Bcl2) and Bcl2-associated X protein (Bax) protein were measured by Western blotting. The main results of this study showed that the metabolic alterations observed in diabetic rats (hyperglycemia and hypoinsulinemia) increased p38 expression and decreased p-Akt expression, suggesting that cell survival was altered and cell death was induced, which was confirmed by FJC staining. Therefore, the metabolic conditions observed during neonatal hyperglycemia may contribute to the harmful effect of diabetes on the CNS in a crucial phase of postnatal neuronal development.
Assuntos
Encéfalo/patologia , Morte Celular/fisiologia , Hiperglicemia/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Animais , Encéfalo/metabolismo , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patologia , Feminino , Sistema de Sinalização das MAP Quinases/fisiologia , Masculino , Neurônios/metabolismo , Fosforilação , Ratos Wistar , Proteína X Associada a bcl-2/metabolismoRESUMO
Cystathionine-ß-synthase (CBS) deficiency is the main cause of homocystinuria. Homocysteine (Hcy), methionine, and other metabolites of Hcy accumulate in the body of affected patients. Despite the fact that thromboembolism represents the major cause of morbidity in CBS-deficient patients, the mechanisms of cardiovascular alterations found in homocystinuria remain unclear. In this work, we evaluated the lipid and inflammatory profile, oxidative protein damage, and the activities of the enzymes paraoxonase (PON1) and butyrylcholinesterase (BuChE) in plasma of CBS-deficient patients at diagnosis and during the treatment (protein-restricted diet supplemented with pyridoxine, folic acid, betaine, and vitamin B12). We also investigated the effect of folic acid and vitamin B12 on these parameters. We found a significant decrease in HDL cholesterol and apolipoprotein A1 (ApoA-1) levels, as well as in PON1 activity in both untreated and treated CBS-deficient patients when compared to controls. BuChE activity and IL-6 levels were significantly increased in not treated patients. Furthermore, significant positive correlations between PON1 activity and sulphydryl groups and between IL-6 levels and carbonyl content were verified. Moreover, vitamin B12 was positively correlated with PON1 and ApoA-1 levels, while folic acid was inversely correlated with total Hcy concentration, demonstrating the importance of this treatment. Our results also demonstrated that CBS-deficient patients presented important alterations in biochemical parameters, possibly caused by the metabolites of Hcy, as well as by oxidative stress, and that the adequate adherence to the treatment is essential to revert or prevent these alterations.
Assuntos
Arildialquilfosfatase/sangue , Butirilcolinesterase/sangue , Homocistinúria/sangue , Lipídeos/sangue , Oxidantes/sangue , Adolescente , Adulto , Estudos de Casos e Controles , Criança , Pré-Escolar , Cistationina beta-Sintase/deficiência , Cistationina beta-Sintase/genética , Feminino , Ácido Fólico/sangue , Ácido Fólico/fisiologia , Homocistinúria/genética , Humanos , Masculino , Estresse Oxidativo/fisiologia , Vitamina B 12/sangue , Vitamina B 12/fisiologia , Adulto JovemRESUMO
Recently, the consequences of diabetes on the central nervous system (CNS) have received great attention. However, the mechanisms by which hyperglycemia affects the central nervous system remain poorly understood. In addition, recent studies have shown that hyperglycemia induces oxidative damage in the adult rat brain. In this regard, no study has assessed oxidative stress as a possible mechanism that affects the brain normal function in neonatal hyperglycemic rats. Thus, the present study aimed to investigate whether neonatal hyperglycemia elicits oxidative stress in the brain of neonate rats subjected to a streptozotocin-induced neonatal hyperglycemia model (5-day-old rats). The activities of glucose-6-phosphate-dehydrogenase (G6PD), 6-phosphogluconate-dehydrogenase (6-PGD), NADPH oxidase (Nox), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSHPx), the production of superoxide anion, the thiobarbituric acid-reactive substances (TBA-RS), and the protein carbonyl content were measured. Neonatal hyperglycemic rats presented increased activities of G6PD, 6PGD, and Nox, which altogether may be responsible for the enhanced production of superoxide radical anion that was observed. The enhanced antioxidant enzyme activities (SOD, CAT, and GSHPx) that were observed in neonatal hyperglycemic rats, which may be caused by a rebound effect of oxidative stress, were not able to hinder the observed lipid peroxidation (TBA-RS) and protein damage in the brain. Consequently, these results suggest that oxidative stress could represent a mechanism that explains the harmful effects of neonatal hyperglycemia on the CNS.
Assuntos
Encéfalo/enzimologia , Encéfalo/patologia , Hiperglicemia/patologia , NADPH Oxidases/metabolismo , Estresse Oxidativo , Via de Pentose Fosfato , Animais , Animais Recém-Nascidos , Catalase/metabolismo , Glutationa Peroxidase/metabolismo , Carbonilação Proteica , Ratos Wistar , Superóxidos/metabolismo , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismoRESUMO
Maple Syrup Urine Disease (MSUD) is a metabolic disorder caused by a severe deficiency of the branched-chain α-keto acid dehydrogenase complex activity which leads to the accumulation of branched-chain amino acids (BCAA) leucine (Leu), isoleucine and valine and their respective α-keto-acids in body fluids. The main symptomatology presented by MSUD patients includes ketoacidosis, failure to thrive, poor feeding, apnea, ataxia, seizures, coma, psychomotor delay and mental retardation, but, the neurological pathophysiologic mechanisms are poorly understood. The treatment consists of a low protein diet and a semi-synthetic formula restricted in BCAA and supplemented with essential amino acids. It was verified that MSUD patients present L-carnitine (L-car) deficiency and this compound has demonstrated an antioxidant and anti-inflammatory role in metabolic diseases. Since there are no studies in the literature reporting the inflammatory profile of MSUD patients and the L-car role on the inflammatory response in this disorder, the present study evaluates the effect of L-car supplementation on plasma inflammatory cytokines interleukin-1ß (IL-1ß), interleukin-6 (IL-6), interferon-gamma (INF-É£), and a correlation with malondialdehyde (MDA), as a marker of oxidative damage, and with free L-car plasma levels in treated MSUD patients. Significant increases of IL-1ß, IL-6, and INF-É£ were observed before the treatment with L-car. Moreover, there is a negative correlation between all cytokines tested and L-car concentrations and a positive correlation among the MDA content and IL-1ß and IL-6 values. Our data show that L-car supplementation can improve cellular defense against inflammation and oxidative stress in MSUD patients and may represent an additional therapeutic approach to the patients affected by this disease.
Assuntos
Carnitina/uso terapêutico , Suplementos Nutricionais , Mediadores da Inflamação/sangue , Doença da Urina de Xarope de Bordo/sangue , Doença da Urina de Xarope de Bordo/tratamento farmacológico , Criança , Pré-Escolar , Feminino , Humanos , Inflamação/sangue , Inflamação/tratamento farmacológico , MasculinoRESUMO
There is increasing evidence suggesting that oxidative stress plays an important role in the development of many chronic and degenerative conditions such as diabetic encephalopathy and depression. Considering that diabetic rats and mice present higher depressive-like behaviour when submitted to the forced swimming test and that treatment with insulin and/or clonazepam is able to reverse the behavioural changes of the diabetic rats, the present work investigated the antioxidant status, specifically total antioxidant reactivity and antioxidant potential of insulin and clonazepam, as well as the effect of this drugs upon protein oxidative damage and reactive species formation in cortex, hippocampus and striatum from diabetic rats submitted to forced swimming test. It was verified that longer immobility time in diabetic rats and insulin plus clonazepam treatment reversed this depressive-like behaviour. Moreover, data obtained in this study allowed to demonstrate through different parameters such as protein carbonyl content, 2'7'-dichlorofluorescein oxidation, catalase, superoxide dismutase, glutathione peroxidase assay, total radical-trapping antioxidant potential and total antioxidant reactivity that there is oxidative stress in cortex, hippocampus and striatum from diabetic rats under depressive-like behaviour and highlight the insulin and/or clonazepam effect in these different brain areas, restoring antioxidant status and protein damage.
Assuntos
Anticonvulsivantes/uso terapêutico , Encefalopatias/complicações , Clonazepam/uso terapêutico , Depressão/tratamento farmacológico , Diabetes Mellitus Experimental/complicações , Hipoglicemiantes/uso terapêutico , Insulina/uso terapêutico , Animais , Antioxidantes/metabolismo , Córtex Cerebral/metabolismo , Córtex Cerebral/patologia , Corpo Estriado/metabolismo , Corpo Estriado/patologia , Depressão/etiologia , Hipocampo/metabolismo , Hipocampo/patologia , Masculino , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismoRESUMO
Diabetes mellitus is characterized by hyperglycemia resulting from defects on insulin secretion, insulin action, or both. It has recently become clear that the central nervous system is not spared from the deleterious effects of diabetes, since diabetic encephalopathy was recognized as a complication of this heterogeneous metabolic disorder. There is a well recognized association between depression and diabetes, once prevalence of depression in diabetic patients is higher than in general population, and clonazepam is being used to treat this complication. Oxidative stress is widely accepted as playing a key mediatory role in the development and progression of diabetes and its complications. In this work we analyzed DNA damage by comet assay and lipid damage in prefrontal cortex, hippocampus and striatum of streptozotocin-induced diabetic rats submitted to the forced swimming test. It was verified that the diabetic group presented DNA and lipid damage in the brain areas evaluated, when compared to the control groups. Additionally, a significant reduction of the DNA and lipid damage in animals treated with insulin and/or clonazepam was observed. These data suggest that the association of these two drugs could protect against DNA and lipid damage in diabetic rats submitted to the forced swimming test, an animal model of depression.
Assuntos
Encéfalo/efeitos dos fármacos , Clonazepam/uso terapêutico , Depressão/tratamento farmacológico , Diabetes Mellitus Experimental/tratamento farmacológico , Moduladores GABAérgicos/uso terapêutico , Hipoglicemiantes/uso terapêutico , Insulina/uso terapêutico , Animais , Comportamento Animal/efeitos dos fármacos , Encéfalo/metabolismo , Clonazepam/farmacologia , Dano ao DNA/efeitos dos fármacos , Depressão/complicações , Depressão/metabolismo , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/metabolismo , Moduladores GABAérgicos/farmacologia , Hipoglicemiantes/farmacologia , Insulina/farmacologia , Masculino , Malondialdeído/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Ratos , Ratos WistarRESUMO
CONTEXT: It is known that oxidative stress occurs in peripheral blood in an experimental animal model of diabetes and depression, and acute treatment with insulin and clonazepam (CNZ) has a protective effect on oxidative stress in this model. OBJECTIVE: This study evaluated the effect of insulin plus CNZ on oxidative stress parameters in the liver of diabetic male rats induced with streptozotocin (STZ) and subjected to forced swimming test (FST). MATERIALS AND METHODS: Diabetes was induced by a single intraperitoneal (i.p.) dose of STZ 60 mg/kg in male Wistar rats. Insulin (4 IU/kg) plus CNZ acute i.p. treatment (0.25 mg/kg) was administered 24, 5 and 1 h before the FST. Nondiabetic control rats received i.p. injections of saline (1 mL/kg). Protein oxidative damage was evaluated by carbonyl formation and the antioxidant redox parameters were analyzed by the measurements of enzymatic activities of the superoxide dismutase (SOD), catalase and glyoxalase I (GLO). Glycemia levels also were determined. RESULTS: Our present study has shown an increase in carbonyl content from diabetic rats subjected to FST (2.04 ± 0.55), while the activity of catalase (51.83 ± 19.02) and SOD (2.30 ± 1.23) were significantly decreased in liver from these animals, which were reverted by the treatment. Also, the activity of GLO (0.15 ± 0.02) in the liver of the animals was decreased. DISCUSSION AND CONCLUSION: Our findings showed that insulin plus CNZ acute treatment ameliorate the antioxidant redox parameters and protect against protein oxidative damage in the liver of diabetic rats subjected to FST.
Assuntos
Clonazepam/farmacologia , Depressão/tratamento farmacológico , Diabetes Mellitus Experimental/tratamento farmacológico , Insulina/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Animais , Catalase/metabolismo , Clonazepam/administração & dosagem , Depressão/fisiopatologia , Diabetes Mellitus Experimental/fisiopatologia , Modelos Animais de Doenças , Quimioterapia Combinada , Insulina/administração & dosagem , Lactoilglutationa Liase/metabolismo , Fígado/efeitos dos fármacos , Fígado/patologia , Masculino , Oxirredução/efeitos dos fármacos , Carbonilação Proteica/efeitos dos fármacos , Ratos , Ratos Wistar , Estreptozocina , Superóxido Dismutase/metabolismo , Fatores de TempoRESUMO
Phenylketonuria (PKU) is caused by deficiency of phenylalanine hydroxylase, leading to accumulation of phenylalanine and its metabolites. Clinical features of PKU patients include mental retardation, microcephaly, and seizures. Oxidative stress has been found in these patients, and is possibly related to neurophysiopatology of PKU. Regular exercise can leads to adaptation of antioxidant system, improving its capacity to detoxification reactive species. The aim of this study was to verify the effects of regular exercise on oxidative stress parameters in the brain of hyperphenylalaninemic rats. Animals were divided into sedentary (Sed) and exercise (Exe) groups, and subdivided into saline (SAL) and hyperphenylalaninemia (HPA). HPA groups were induced HPA through administration of alpha-methylphenylalanine and phenylalanine for 17 days, while SAL groups (n = 16-20) received saline. Exe groups conducted 2-week aerobic exercise for 20 min/day. At 18th day, animals were killed and the brain was homogenized to determine thiobarbituric acid reactives substances (TBA-RS) content, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities. Soleus muscles were collected to determine glycogen content as a marker of oxidative adaptation. Exe groups showed enhanced glycogen content. HPA condition caused an increase in TBA-RS and SOD, and reduces CAT and GPx. Exercise was able to prevent all changes seen in the HPA group, reaching control values, except for SOD activity. No changes were found in the ExeSAL group compared to SedSAL. Hyperphenylalaninemic rats were more responsive to the benefits provided by regular exercise. Physical training may be an interesting strategy to restore the antioxidant system in HPA.
Assuntos
Química Encefálica/fisiologia , Estresse Oxidativo/fisiologia , Fenilcetonúrias/metabolismo , Condicionamento Físico Animal/fisiologia , Animais , Antioxidantes/metabolismo , Catalase/metabolismo , Modelos Animais de Doenças , Glutationa Peroxidase/metabolismo , Glicogênio/metabolismo , Músculo Esquelético/metabolismo , Fenilalanina/efeitos adversos , Fenilalanina/análogos & derivados , Fenilalanina Hidroxilase/deficiência , Fenilcetonúrias/induzido quimicamente , Ratos , Ratos Wistar , Superóxido Dismutase/metabolismo , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismoRESUMO
5-Oxoproline accumulates in glutathione synthetase deficiency, an autossomic recessive inherited disorder clinically characterized by hemolytic anemia, metabolic acidosis, and severe neurological symptoms whose mechanisms are poorly known. In the present study we investigated the effects of acute subcutaneous administration of 5-oxoproline to verify whether oxidative stress is elicited by this metabolite in vivo in cerebral cortex and cerebellum of 14-day-old rats. Our results showed that the acute administration of 5-oxoproline is able to promote both lipid and protein oxidation, to impair brain antioxidant defenses, to alter SH/SS ratio and to enhance hydrogen peroxide content, thus promoting oxidative stress in vivo, a mechanism that may be involved in the neuropathology of gluthatione synthetase deficiency.
Assuntos
Antioxidantes/metabolismo , Encefalopatias Metabólicas Congênitas/induzido quimicamente , Cerebelo/efeitos dos fármacos , Cérebro/efeitos dos fármacos , Peroxidação de Lipídeos/efeitos dos fármacos , Proteínas do Tecido Nervoso/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Ácido Pirrolidonocarboxílico/toxicidade , Fatores Etários , Animais , Antioxidantes/fisiologia , Encefalopatias Metabólicas Congênitas/metabolismo , Cerebelo/metabolismo , Cérebro/metabolismo , Modelos Animais de Doenças , Glutationa Sintase/deficiência , Peroxidação de Lipídeos/fisiologia , Proteínas do Tecido Nervoso/fisiologia , Estresse Oxidativo/fisiologia , Ácido Pirrolidonocarboxílico/metabolismo , Ratos , Ratos WistarRESUMO
N-Acetylaspartic acid accumulates in Canavan Disease, a severe inherited neurometabolic disease clinically characterized by severe mental retardation, hypotonia, macrocephaly and generalized tonic and clonic type seizures. Considering that the mechanisms of brain damage in this disease remain poorly understood, in the present study we investigated the in vitro and in vivo effects of N-acetylaspartic acid on the activities of catalase, superoxide dismutase and glutathione peroxidase, as well as on hydrogen peroxide concentration in cerebral cortex of 14-day-old rats. Catalase and glutathione peroxidase activities were significantly inhibited, while hydrogen peroxide concentration was significantly enhanced by N-acetylaspartic acid both in vitro and in vivo. In contrast, superoxide dismutase activity was not altered by N-acetylaspartic acid. Our results clearly show that N-acetylaspartic acid impairs the enzymatic antioxidant defenses in rat brain. This could be involved in the pathophysiological mechanisms responsible for the brain damage observed in patients affected by Canavan Disease.
Assuntos
Antioxidantes/metabolismo , Ácido Aspártico/análogos & derivados , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Catalase/metabolismo , Glutationa Peroxidase/metabolismo , Peróxido de Hidrogênio/metabolismo , Superóxido Dismutase/metabolismo , Animais , Ácido Aspártico/metabolismo , Ácido Aspártico/toxicidade , Ácido Aspártico/urina , Encéfalo/enzimologia , Doença de Canavan/metabolismo , Doença de Canavan/fisiopatologia , Catalase/efeitos dos fármacos , Esquema de Medicação , Feminino , Glutationa Peroxidase/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/fisiologia , Ratos , Ratos Wistar , Superóxido Dismutase/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/fisiologiaRESUMO
Tyrosine levels are abnormally elevated in tissues and physiological fluids of patients with inborn errors of tyrosine catabolism especially in tyrosinemia type II which is caused by deficiency of tyrosine aminotransferase (TAT) and provokes eyes, skin and central nervous system disturbances. We have recently reported that tyrosine promoted oxidative stress in vitro but the exact mechanisms of brain damage in these disorder are poorly known. In the present study, we investigated the in vivo effect of L-tyrosine (500 mg/Kg) on oxidative stress indices in cerebral cortex homogenates of 14-day-old Wistar rats. A single injection of L-tyrosine decreased glutathione (GSH) and thiol-disulfide redox state (SH/SS ratio) while thiobarbituric acid-reactive substances, protein carbonyl content and glucose-6-phosphate dehydrogenase activity were enhanced. In contrast, the treatment did not affect ascorbic acid content, and the activities of superoxide dismutase, catalase and glutathione peroxidase. These results indicate that acute administration of L-tyrosine may impair antioxidant defenses and stimulate oxidative damage to lipids and proteins in cerebral cortex of young rats in vivo. This suggests that oxidative stress may represent a pathophysiological mechanism in hypetyrosinemic patients.
Assuntos
Córtex Cerebral/metabolismo , Glutationa/metabolismo , Metabolismo dos Lipídeos/efeitos dos fármacos , Proteínas do Tecido Nervoso/metabolismo , Tirosina/farmacologia , Animais , Ácido Ascórbico/metabolismo , Catalase/metabolismo , Córtex Cerebral/efeitos dos fármacos , Dissulfetos/metabolismo , Glucosefosfato Desidrogenase/metabolismo , Glutationa Peroxidase/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Oxirredução , Carbonilação Proteica/efeitos dos fármacos , Ratos , Ratos Wistar , Estimulação Química , Compostos de Sulfidrila/metabolismo , Superóxido Dismutase/metabolismo , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismoRESUMO
Maple syrup urine disease (MSUD) is an inherited deficiency of the branched-chain α-keto dehydrogenase complex, characterized by accumulation of the branched-chain amino acids (BCAAs) and their respective branched chain α-keto-acids (BCKAs), as well as by the presence of alloisoleucine (Allo). Studies have shown that oxidative stress is involved in the pathophysiology of MSUD. In this work, we investigated using the comet assay whether Allo, BCAAs and BCKAs could induce in vitro DNA damage, as well as the influence of l-Carnitine (L-Car) upon DNA damage. We also evaluated urinary 8-hydroxydeoguanosine (8-OHdG) levels, an oxidative DNA damage biomarker, in MSUD patients submitted to a restricted diet supplemented or not with L-Car. All tested concentrations of metabolites (separated or incubated together) induced in vitro DNA damage, and the co-treatment with L-Car reduced these effects. We found that Allo induced the higher DNA damage class and verified a potentiation of DNA damage induced by synergistic action between metabolites. In vivo, it was observed a significant increase in 8-OHdG levels, which was reversed by L-Car. We demonstrated for the first time that oxidative DNA damage is induced not only by BCAAs and BCKAs but also by Allo and we reinforce the protective effect of L-Car.
Assuntos
Aminoácidos/administração & dosagem , Carnitina/uso terapêutico , Dano ao DNA , Suplementos Nutricionais , Doença da Urina de Xarope de Bordo , Substâncias Protetoras/uso terapêutico , 8-Hidroxi-2'-Desoxiguanosina , Aminoácidos/sangue , Aminoácidos/urina , Criança , Pré-Escolar , Ensaio Cometa , Desoxiguanosina/análogos & derivados , Desoxiguanosina/urina , Humanos , Doença da Urina de Xarope de Bordo/sangue , Doença da Urina de Xarope de Bordo/dietoterapia , Doença da Urina de Xarope de Bordo/genética , Doença da Urina de Xarope de Bordo/urinaRESUMO
Lysosomal Storage Disorders (LSD) comprise a heterogeneous group of >50 genetic disorders caused by mutations in genes that encode lysosomal enzymes, transport proteins or other gene products essential for a functional lysosomal system. As a result, abnormal accumulation of substrates within the lysosome leads to a progressive cellular impairment and dysfunction of numerous organs and systems. The exact mechanisms underlying the pathophysiology of LSD remain obscure. Previous studies proposed a relationship between oxidative stress and the pathogenesis of several inborn errors of metabolism, including LSD. Considering these points, in this paper it was reviewed oxidative stress and emerging antioxidant therapy in LSD, emphasizing studies with biological samples from patients affected by this group of conditions. These studies allow presuming that metabolites accumulated in LSD cause an increase of lysosomes' number and size, which may induce excessive production of reactive species and/or deplete the tissue antioxidant capacity, leading to damage in biomolecules. In vitro and in vivo evidence showed that cell oxidative process occurs in LSD and probably contributes to the pathophysiology of these disorders. In this context, it is possible to suggest that, in the future, antioxidants could come to be used as adjuvant therapy for LSD patients.
Assuntos
Doenças por Armazenamento dos Lisossomos/fisiopatologia , Estresse Oxidativo , Antioxidantes/uso terapêutico , Biomarcadores/análise , Humanos , Doenças por Armazenamento dos Lisossomos/diagnóstico , Doenças por Armazenamento dos Lisossomos/tratamento farmacológico , Doenças por Armazenamento dos Lisossomos/metabolismo , Oxirredução/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/fisiologiaRESUMO
Maple syrup urine disease (MSUD), or branched-chain α-keto aciduria, is an inherited disorder that is caused by a deficiency in branched-chain α-keto acid dehydrogenase complex (BCKAD) activity. Blockade of this pathway leads to the accumulation of the branched-chain amino acids (BCAAs), leucine, isoleucine, and valine, and their respective ketoacids in tissues. The main clinical symptoms presented by MSUD patients include ketoacidosis, hypoglycemia, opisthotonos, poor feeding, apnea, ataxia, convulsions, coma, psychomotor delay, and mental retardation. Although increasing evidence indicates that oxidative stress is involved in the pathophysiology of this disease, the mechanisms of the brain damage caused by this disorder remain poorly understood. In the present study, we investigated the effect of BCAAs on some oxidative stress parameters and evaluated the efficacy of L-carnitine (L-car), an efficient antioxidant that may be involved in the reduction of oxidative damage observed in some inherited neurometabolic diseases, against these possible pro-oxidant effects of a chronic MSUD model in the cerebral cortex and cerebellum of rats. Our results showed that chronic BCAA administration was able to promote both lipid and protein oxidation, impair brain antioxidant defenses, and increase reactive species production, particularly in the cerebral cortex, and that L-car was able to prevent these effects. Taken together, the present data indicate that chronic BCAA administration significantly increased oxidative damage in the brains of rats subjected to a chronic model of MSUD and that L-car may be an efficient antioxidant in this disorder.
Assuntos
Encéfalo/patologia , Carnitina/farmacologia , Doença da Urina de Xarope de Bordo/induzido quimicamente , Doença da Urina de Xarope de Bordo/patologia , Estresse Oxidativo/efeitos dos fármacos , Aminoácidos de Cadeia Ramificada/farmacologia , Animais , Catalase/metabolismo , Modelos Animais de Doenças , Glutationa/metabolismo , Modelos Biológicos , Carbonilação Proteica/efeitos dos fármacos , Ratos Wistar , Superóxido Dismutase/metabolismo , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismoRESUMO
Maple syrup urine disease (MSUD) is a disorder of branched-chain amino acids (BCAA). The defect in the branched-chain α-keto acid dehydrogenase complex activity leads to an accumulation of these compounds and their corresponding α-keto-acids and α-hydroxy-acids. Studies have shown that oxidative stress may be involved in neuropathology of MSUD. L-carnitine (L-car), which has demonstrated an important role as antioxidant by reducing and scavenging free radicals formation and by enhancing the activity of antioxidant enzymes, have been used in the treatment of some metabolic rare disorders. This study evaluated the oxidative stress parameters, di-tyrosine, isoprostanes and antioxidant capacity, in urine of MSUD patients under protein-restricted diet supplemented or not with L-car capsules at a dose of 50 mg kg(-1) day(-1). It was also determined urinary α-keto isocaproic acid levels as well as blood free L-car concentrations in blood. It was found a deficiency of carnitine in patients before the L-car supplementation. Significant increases of di-tyrosine and isoprostanes, as well as reduced antioxidant capacity, were observed before the treatment with L-car. The L-car supplementation induced beneficial effects on these parameters reducing the di-tyrosine and isoprostanes levels and increasing the antioxidant capacity. It was also showed a significant increase in urinary of α-ketoisocaproic acid after 2 months of L-car treatment, compared to control group. In conclusion, our results suggest that L-car may have beneficial effects in the treatment of MSUD by preventing oxidative damage to the cells and that urine can be used to monitorize oxidative damage in patients affected by this disease.
Assuntos
Biomarcadores/urina , Suplementos Nutricionais , Doença da Urina de Xarope de Bordo/urina , Aminoácidos/urina , Análise de Variância , Antioxidantes/metabolismo , Criança , Pré-Escolar , Dinoprosta/análogos & derivados , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Isoprostanos/urina , Cetoácidos/urina , Masculino , Doença da Urina de Xarope de Bordo/dietoterapia , Espectrometria de Massas em Tandem , Tirosina/urinaRESUMO
Maple syrup urine disease (MSUD) is an inherited disorder caused by severe deficient activity of the branched-chain α-keto acid dehydrogenase complex involved in the degradation pathway of branched-chain amino acids (BCAAs) and their α-ketoacid derivatives. MSUD patients generally present ketoacidosis, poor feeding, ataxia, coma, psychomotor delay, mental retardation and brain abnormalites. Treatment consists of dietary restriction of the BCAA (low protein intake) supplemented by a BCAA-free amino acid mixture. Although the mechanisms of brain damage in MSUD are poorly known, previous studies have shown that oxidative stress may be involved in the neuropathology of this disorder. In this regard, it was recently reported that MSUD patients have deficiency of l-carnitine (l-car), a compound with antioxidant properties that is used as adjuvant therapy in various inborn errors of metabolism. In this work, we investigated DNA damage determined by the alkaline comet assay in peripheral whole blood leukocytes of MSUD patients submitted to a BCAA-restricted diet supplemented or not with l-car. We observed a significant increase of DNA damage index (DI) in leukocytes from MSUD patients under BCAA-restricted diet as compared to controls and that l-car supplementation significantly decreased DNA DI levels. It was also found a positive correlation between DI and MDA content, a marker of lipid peroxidation, and an inverse correlation between DI and l-car levels. Taken together, our present results suggest a role for reactive species and the involvement of oxidative stress in DNA damage in this disorder. Since l-car reduced DNA damage, it is presumed that dietary supplementation of this compound may serve as an adjuvant therapeutic strategy for MSUD patients in addition to other therapies.
Assuntos
Carnitina/administração & dosagem , Dano ao DNA , Leucócitos/metabolismo , Doença da Urina de Xarope de Bordo/tratamento farmacológico , Doença da Urina de Xarope de Bordo/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Complexo Vitamínico B/administração & dosagem , Criança , Pré-Escolar , Feminino , Humanos , Leucócitos/patologia , Masculino , Doença da Urina de Xarope de Bordo/genética , Doença da Urina de Xarope de Bordo/patologiaRESUMO
Maple syrup urine disease (MSUD) is an inherited aminoacidopathy caused by a deficiency in branched-chain α-keto acid dehydrogenase complex activity that leads to the accumulation of the branched-chain amino acids (BCAAs) leucine (Leu), isoleucine, and valine and their respective α-keto-acids, α-ketoisocaproic acid (KIC), α keto-ß-methylvaleric acid, and α-ketoisovaleric acid. The major clinical features presented by MSUD patients include ketoacidosis, failure to thrive, poor feeding, apnea, ataxia, seizures, coma, psychomotor delay, and mental retardation; however, the pathophysiology of this disease is poorly understood. MSUD treatment consists of a low protein diet supplemented with a mixture containing micronutrients and essential amino acids but excluding BCAAs. Studies have shown that oxidative stress may be involved in the neuropathology of MSUD, with the existence of lipid and protein oxidative damage in affected patients. In recent years, studies have demonstrated the antioxidant role of L-carnitine (L-Car), which plays a central function in cellular energy metabolism and for which MSUD patients have a deficiency. In this work, we investigated the in vitro effect of Leu and KIC in the presence or absence of L-Car on DNA damage in peripheral whole blood leukocytes using the alkaline comet assay with silver staining and visual scoring. Leu and KIC resulted in a DNA damage index that was significantly higher than that of the control group, and L-Car was able to significantly prevent this damage, mainly that due to KIC.