In vitro effect of globotriaosylceramide on electron transport chain complexes and redox parameters.

Fabry disease (FD) is an X-linked inherited disease and occurs due to mutations in GLA gene that encodes the α-galactosidase enzyme. Consequently, there is an accumulation of enzyme substrates, namely globotriaosylceramide (GB3). FD is a multisystemic disease, caused by storage of GB3 in vascular endothelia, with significant renal, cardiac and vascular involvement. The aim of this work was to evaluate the in vitro effect of GB3 on electron transport chain complexes (ETC) and redox parameters. Biochemical biomarkers were determined in homogenates of cerebral cortex, kidneys and liver of Wistar rats in the presence or absence of GB3 at concentrations of 3, 6, 9 and 12 mg/L. We found that GB3 caused an increase of ETC complexes II and IV activities, increased production of reactive species and decreased superoxide dismutase enzyme activity in homogenates of cerebral cortex. As well also increased production of reactive species and superoxide dismutase activity in kidney homogenates. The results obtained in our work suggest that GB3 interferes in ETC complexes II and IV activities, however, the magnitude of this increase seems to be too low to present a physiologically importance. However, the imbalance in cellular redox state indicating that these alterations may be involved in the pathophysiology of FD, mainly in renal and cerebral manifestations.

Synthesis and antioxidant activity of 3-(Pyridin-2-ylmethyl)-1,3-thiazinan(thiazolidin)-4-ones.

The antioxidant properties of two series of thiazolidinones and thiazinanones were reported. The novel six-membered thiazinanones were synthesized from the efficient multicomponent reaction of 2-picolylamine (2-aminomethylpyridine), arenaldehydes, and the 3-mercaptopropionic acid in moderate to excellent yields. These novel compounds were fully identified and characterized by NMR and GC-MS techniques. In vitro antioxidant activities of all compounds were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) tests. The antioxidant assays of thiobarbituric acid reactive species and total thiol content levels in the cerebral cortex and liver of rats were also performed. Thiazinanone 5a showed the best radical scavenging activity in DPPH and ABTS tests, as well as reduced lipid peroxidation and increased total thiol group in biological systems. Altogether, the results may be considered a good starting point for the discovery of a new radical scavenger.

Neurological damage in MSUD: the role of oxidative stress.

Maple syrup urine disease (MSUD) is a metabolic disease caused by a deficiency in the branched-chain α-keto acid dehydrogenase complex, leading to the accumulation of branched-chain keto acids and their corresponding branched-chain amino acids (BCAA) in patients. Treatment involves protein-restricted diet and the supplementation with a specific formula containing essential amino acids (except BCAA) and micronutrients, in order to avoid the appearance of neurological symptoms. Although the accumulation of toxic metabolites is associated to appearance of symptoms, the mechanisms underlying the brain damage in MSUD remain unclear, and new evidence has emerged indicating that oxidative stress contributes to this damage. In this context, this review addresses some of the recent findings obtained from cells lines, animal studies, and from patients indicating that oxidative stress is an important determinant of the pathophysiology of MSUD. Recent works have shown that the metabolites accumulated in the disease induce morphological alterations in C6 glioma cells through nitrogen reactive species generation. In addition, several works demonstrated that the levels of important antioxidants decrease in animal models and also in MSUD patients (what have been attributed to protein-restricted diets). Also, markers of lipid, protein, and DNA oxidative damage have been reported in MSUD, probably secondary to the high production of free radicals. Considering these findings, it is well-established that oxidative stress contributes to brain damage in MSUD, and this review offers new perspectives for the prevention of the neurological damage in MSUD, which may include the use of appropriate antioxidants as a novel adjuvant therapy for patients.

Green juice as a protector against reactive species in rats.

INTRODUCTION: Green juice is popularly known for introducing antioxidants, improving intestinal function and reducing weight gain. OBJECTIVES: In the present study we determine the antioxidant effect of green juice comparing it with orange juice. METHODS: Rats were divided into three experimental groups and submitted to supplementation for 15 days: the (GJ) group received green juice, the (OJ) group received orange juice and the control group received water. We evaluated the antioxidant activity and total phenolic content of green and orange juices, as well as rat weight gain. We also investigated some oxidative stress parameters, namely thiobarbituric acid-reactive substances (TBARS), superoxide dismutase and catalase in rat cerebral cortex. RESULTS AND DISCUSSION: Results showed that GJ had significantly less weight gain than the control group. With respect to antioxidant activity screening, the remaining percentage of DPPH at dilutions 1:10, 1:100 and 1:1000 of green juice was 22.8%, 58% and 78%, and orange juice, at the same dilutions, was 5.6%, 5.6% and 77.2%, respectively. The ability of juices to reduce the ABTS radical was 3.5 mmol trolox/L for green juice and 5.2 mmol trolox/L for orange juice. Additionally, the green juice did not present any difference in total phenolic acid content when compared to orange juice. TBARS were reduced in GJ and OJ. Besides, GJ supplementation decreased catalase activity. In conclusion, our data showed that green juice reduced weight gain, lipoperoxidation and catalase activity, suggesting that this supplementation may have a protective effect against reactive species.

Introducción: El zumo verde es conocido popularmente como fuente de antioxidantes, mejorando la función intestinal y reduciendo la ganancia de peso. Objetivos: En este estudio determinamos el efecto antioxidante del zumo verde en comparación con el zumo de naranja. Métodos: Se dividió a las ratas en tres grupos experimentales y se las sometió a un suplemento durante 15 días: el grupo ZV recibió zumo verde, el grupo ZN recibió zumo de naranja y el grupo control recibió agua. Evaluamos la actividad antioxidante y el contenido total en fenoles de los zumos verde y de naranja, así como la ganancia de peso en las ratas. También investigamos algunos parámetros del estrés oxidativo, en concreto las sustancias reactivas del ácido tiobarbitúrico (SRATB), la superóxido dismutasa y la catalasa en la corteza cerebral de las ratas. Resultados y discusión: Los resultados mostraron que el ZV producía una ganancia de peso significativamente menor que en el grupo control. Con respecto al estudio de la actividad antioxidante, el porcentaje restante de DPPH en diluciones al 1:10, 1:100 y 1:1000 de zumo verde fue del 22,8%, 58% y 78%, y para el zumo de naranja, a las mismas diluciones, fue del 5,6%, 5,6% y 77,2%, respectivamente. La capacidad de los zumos para reducir el radical de ATB fue de 3,5 mmol trolox/l para el zumo verde y de 5,2 mmol trolox/l para el zumo de naranja. Adicionalmente, el zumo verde no mostró ninguna diferencia en el contenido total de ácido fenólico en comparación con el zumo de naranja. Las SRATB se redujeron con el ZV y el ZN. Además, el suplemento con ZV disminuyó la actividad catalasa. En conclusión, nuestros datos mostraron que el zumo verde redujo la ganancia de peso, la lipoperoxidación y la actividad catalasa, lo que sugiere que este suplemento podría tener un efecto protector frente a las especies reactivas.

Green juice as a protector against reactive species in rats / Zumo verde como protector frente a las especies reactivas en ratas

INTRODUCTION: Green juice is popularly known for introducing antioxidants, improving intestinal function and reducing weight gain. OBJECTIVES: In the present study we determine the antioxidant effect of green juice comparing it with orange juice. METHODS: Rats were divided into three experimental groups and submitted to supplementation for 15 days: the (GJ) group received green juice, the (OJ) group received orange juice and the control group received water. We evaluated the antioxidant activity and total phenolic content of green and orange juices, as well as rat weight gain. We also investigated some oxidative stress parameters, namely thiobarbituric acid-reactive substances (TBARS), superoxide dismutase and catalase in rat cerebral cortex. RESULTS AND DISCUSSION: Results showed that GJ had significantly less weight gain than the control group. With respect to antioxidant activity screening, the remaining percentage of DPPH at dilutions 1:10, 1:100 and 1:1000 of green juice was 22.8%, 58% and 78%, and orange juice, at the same dilutions, was 5.6%, 5.6% and 77.2%, respectively. The ability of juices to reduce the ABTS radical was 3.5 mmol trolox/L for green juice and 5.2 mmol trolox/L for orange juice. Additionally, the green juice did not present any difference in total phenolic acid content when compared to orange juice. TBARS were reduced in GJ and OJ. Besides, GJ supplementation decreased catalase activity. In conclusion, our data showed that green juice reduced weight gain, lipoperoxidation and catalase activity, suggesting that this supplementation may have a protective effect against reactive species (AU)

Introducción: El zumo verde es conocido popularmente como fuente de antioxidantes, mejorando la función intestinal y reduciendo la ganancia de peso. Objetivos: En este estudio determinamos el efecto antioxidante del zumo verde en comparación con el zumo de naranja. Métodos: Se dividió a las ratas en tres grupos experimentales y se las sometió a un suplemento durante 15 días: el grupo ZV recibió zumo verde, el grupo ZN recibió zumo de naranja y el grupo control recibió agua. Evaluamos la actividad antioxidante y el contenido total en fenoles de los zumos verde y de naranja, así como la ganancia de peso en las ratas. También investigamos algunos parámetros del estrés oxidativo, en concreto las sustancias reactivas del ácido tiobarbitúrico (SRATB), la superóxido dismutasa y la catalasa en la corteza cerebral de las ratas. Resultados y discusión: Los resultados mostraron que el ZV producía una ganancia de peso significativamente menor que en el grupo control. Con respecto al estudio de la actividad antioxidante, el porcentaje restante de DPPH en diluciones al 1:10, 1:100 y 1:1000 de zumo verde fue del 22,8%, 58% y 78%, y para el zumo de naranja, a las mismas diluciones, fue del 5,6%, 5,6% y 77,2%, respectivamente. La capacidad de los zumos para reducir el radical de ATB fue de 3,5 mmol trolox/l para el zumo verde y de 5,2 mmol trolox/l para el zumo de naranja. Adicionalmente, el zumo verde no mostró ninguna diferencia en el contenido total de ácido fenólico en comparación con el zumo de naranja. Las SRATB se redujeron con el ZV y el ZN. Además, el suplemento con ZV disminuyó la actividad catalasa. En conclusión, nuestros datos mostraron que el zumo verde redujo la ganancia de peso, la lipoperoxidación y la actividad catalasa, lo que sugiere que este suplemento podría tener un efecto protector frente a las especies reactivas (AU)

Binding pattern and toxicological effects of lectins from genus Canavalia on bovine sperm.

The aim of this study was to determine the binding patterns of Canavalia ensiformis (ConA), Canavalia boliviana (ConBol) and Canavalia brasiliensis (ConBr) lectins to bovine sperm and their effects on sperm motility, viability, lipid peroxidation, reactive oxygen species production and fertilization ability. ConA bound to whole spermatozoa, with the exception of the equatorial segment, ConBol did not interact with the acrosome region and ConBr exhibited a fragmented binding pattern. The three lectins decreased sperm motility but did not affect cell viability or lipid peroxidation. Nevertheless, ROS production was increased in comparison to controls and a reduction in the cleavage and blastocyst ratio was induced in comparison to controls. In conclusion, this study determined that structurally similar lectins interact differently with bovine sperm and affect sperm motility, viability, lipid peroxidation, ROS production and fertilization ability in various ways.

Antioxidant capacity and environmentally friendly synthesis of dihydropyrimidin-(2H)-ones promoted by naturally occurring organic acids.

The Biginelli reaction is a multicomponent reaction involving the condensation between an aldehyde, a ß-ketoester, and urea or thiourea, in the presence of an acid catalyst, producing dihydropyrimidinones (DHPMs). Owing to their important pharmacological properties, the DHPMs have been studied by many authors. However, most of the methodologies used for the synthesis of these compounds require drastic reaction conditions. In the current study, we report an efficient and clean procedure for preparing DHPMs by the use of citric acid or tartaric acid as a promoter of the Biginelli synthesis in ethanol as solvent. In addition, we have evaluated the antioxidant capacity of the compounds synthesized by the 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay and the thiobarbituric acid-reactive species test. Two compounds presented antioxidant activity and also reduced lipid peroxidation at concentrations of 200 and 300 µM. In summary, we report an environmentally friendly procedure for the preparation of DHPMs and demonstrate the antioxidant capacity of some of the compounds.

Globotriaosylceramide is correlated with oxidative stress and inflammation in Fabry patients treated with enzyme replacement therapy.

Fabry disease is an X-linked inborn error of glycosphingolipid catabolism due to deficient activity of α-galactosidase A that leads to accumulation of the enzyme substrates, mainly globotriaosylceramide (Gb3), in body fluids and lysosomes of many cell types. Some pathophysiology hypotheses are intimately linked to reactive species production and inflammation, but until this moment there is no in vivo study about it. Hence, the aim of this study was to investigate oxidative stress parameters, pro-inflammatory cytokines and Gb3 levels in Fabry patients under treatment with enzyme replacement therapy (ERT) and finally to establish a possible relation between them. We analyzed urine and blood samples of patients under ERT (n=14) and healthy age-matched controls (n=14). Patients presented decreased levels of antioxidant defenses, assessed by reduced glutathione (GSH), glutathione peroxidase (GPx) activity and increased superoxide dismutase/catalase (SOD/CAT) ratio in erythrocytes. Concerning to the damage to biomolecules (lipids and proteins), we found that plasma levels of malondialdehyde (MDA) and protein carbonyl groups and di-tyrosine (di-Tyr) in urine were increased in patients. The pro-inflammatory cytokines IL-6 and TNF-α were also increased in patients. Urinary Gb3 levels were positively correlated with the plasma levels of IL-6, carbonyl groups and MDA. IL-6 levels were directly correlated with di-Tyr and inversely correlated with GPx activity. This data suggest that pro-inflammatory and pro-oxidant states occur, are correlated and seem to be induced by Gb3 in Fabry patients.

Effect of short- and long-term exposition to high phenylalanine blood levels on oxidative damage in phenylketonuric patients.

Phenylketonuria is the most frequent disturbance of amino acid metabolism. Treatment for phenylketonuric patients consists of phenylalanine intake restriction. However, there are patients who do not adhere to treatment and/or are not submitted to neonatal screening. These individuals are more prone to develop brain damage due to long-lasting toxic effects of high levels of phenylalanine and/or its metabolites. Oxidative stress occurs in late-diagnosed phenylketonuric patients, probably contributing to the neurological damage in this disorder. In this work, we aimed to compare the influence of time exposition to high phenylalanine levels on oxidative stress parameters in phenylketonuric patients who did not adhere to protein restricted diet. We evaluated a large spectrum of oxidative stress parameters in plasma and erythrocytes from phenylketonuric patients with early and late diagnosis and of age-matched healthy controls. Erythrocyte glutathione peroxidase activity and glutathione levels, as well as plasma total antioxidant reactivity were significantly reduced in both groups of patients when compared to the control group. Furthermore, protein oxidative damage, measured by carbonyl formation and sulfhydryl oxidation, and lipid peroxidation, determined by malondialdehyde levels, were significantly increased only in patients exposed for a long time to high phenylalanine concentrations, compared to early diagnosed patients and controls. In conclusion, exposition to high phenylalanine concentrations for a short or long time results in a reduction of non-enzymatic and enzymatic antioxidant defenses, whereas protein and lipid oxidative damage only occurs in patients with late diagnosis.

Amino acids levels and lipid peroxidation in maple syrup urine disease patients.

OBJECTIVE: In the present study we correlated the amino acids, branched-chain alpha-keto acids and alpha-hydroxy acids levels with the thiobarbituric acid-reactive species (TBARS) measurement, a lipid peroxidation parameter, in plasma from treated MSUD patients in order to examine whether these accumulated metabolites could be associated to the oxidative stress present in MSUD. DESIGN AND METHODS: TBARS, amino acids, branched-chain alpha-keto acids and alpha-hydroxy acids concentrations were measured in plasma samples from treated MSUD patients. RESULTS: We verified that plasma TBARS was increased, whereas tryptophan and methionine concentrations were significantly reduced. Furthermore TBARS measurement was inversely correlated to methionine and tryptophan levels. CONCLUSIONS: Considering that methionine and tryptophan have antioxidant activities, the data suggest that the imbalance of these amino acids may be involved with lipid peroxidation in MSUD.

L-carnitine blood levels and oxidative stress in treated phenylketonuric patients.

AIMS: L-carnitine exerts an important role by facilitating the mitochondrial transport of fatty acids, but is also a scavenger of free radicals, protecting cells from oxidative damage. Phenylketonuria (PKU), an inborn error of phenylalanine (Phe) metabolism, is currently treated with a special diet consisting of severe restriction of protein-enriched foods, therefore potentially leading to L-carnitine depletion. The aim of this study was to determine L-carnitine levels and oxidative stress parameters in blood of two groups of PKU patients, with good and poor adherence to treatment. METHODS: Treatment of patients consisted of a low protein diet supplemented with a synthetic amino acids formula not containing Phe, L-carnitine, and selenium. L-carnitine concentrations and the oxidative stress parameters thiobarbituric acid reactive species (TBARS) and total antioxidant reactivity (TAR) were measured in blood of the two groups of treated PKU patients and controls. RESULTS: We verified a significant decrease of serum L-carnitine levels in patients who strictly adhered to the diet, as compared to controls and patients who did not comply with the diet. Furthermore, TBARS measurement was significantly increased and TAR was significantly reduced in both groups of phenylketonuric patients relatively to controls. We also found a significant negative correlation between TBARS and L-carnitine levels and a significant positive correlation between TAR and L-carnitine levels in well-treated PKU patients. CONCLUSIONS: Our results suggest that L-carnitine should be measured in plasma of treated PKU patients, and when a decrease of this endogenous component is detected in plasma, supplementation should be considered as an adjuvant therapy.

Maple syrup urine disease in treated patients: biochemical and oxidative stress profiles.

OBJECTIVE: The objective of this study was to evaluate and correlate the biochemical and oxidative stress profiles in MSUD patients during the dietary treatment. DESIGN AND METHODS: Plasma samples from treated MSUD patients were used to evaluate the biochemical profile and oxidative stress parameters. RESULTS: It was observed that glucose, total cholesterol, albumin and creatinine are reduced and that aspartate aminotransferase and lactate dehydrogenase activities are increased in plasma from MSUD patients under treatment. Besides, it was verified an increase of thiobarbituric acid-reactive species (TBARS) and a decrease of total antioxidant reactivity (TAR). CONCLUSIONS: Our results suggest that oxidative stress occurs in treated MSUD patients and that dietary treatment and clinical conditions associated to the disease can lead to biochemical alterations in these patients.

Hexacosanoic and docosanoic acids plasma levels in patients with cerebral childhood and asymptomatic X-linked adrenoleukodystrophy: Lorenzo's oil effect.

X-linked adrenoleukodystrophy (X-ALD) is an inherited disorder of peroxisomal metabolism, biochemically characterized by deficient beta-oxidation of saturated very long chain fatty acids (VLCFA). The consequent accumulation of these fatty acids in different tissues and in biological fluids is associated with a progressive central and peripheral demyelination, as well as with adrenocortical insufficiency and hypogonadism. Seven variants of this disease have been described, cerebral childhood being the most frequent. The recommended therapy consists of the use of the glyceroltrioleate/glyceroltrierucate mixture known as Lorenzo's Oil (LO), combined with a VLCFA-poor diet, but only in asymptomatic patients will this treatment prevent the progression of the symptomatology. In the present study we evaluated the biochemical course of patients with cerebral childhood (CCER) and asymptomatic clinical forms of X-ALD treated with LO associated with a VLCFA-restricted diet. We observed that hexacosanoic acid plasma concentrations and hexacosanoic/docosanoic ratio were significantly reduced in CCER patients during treatment when compared with diagnosis. Hexacosanoic acid plasma level was significantly reduced when compared with that at diagnosis and achieved the normal levels only in asymptomatic patients under LO treatment. In asymptomatic patients the magnitude of hexacosanoic acid decrease was higher than that of the CCER patients. These results show the good biochemical response of LO treatment in asymptomatic X-ALD patients. It is possible to suppose that this could be correlated with the prevention of the appearance of neurological signals in this group of patients treated with LO.

Oxidative stress in plasma from maple syrup urine disease patients during treatment.

Maple Syrup Urine Disease (MSUD) is an autosomal recessive metabolic disorder caused by a deficiency of branched-chain alpha-keto acid dehydrogenase complex activity leading to accumulation of the branched-chain amino acids leucine, isoleucine and valine and their corresponding branched-chain alpha-keto acids. Affected patients usually present hypoglycemia, ketoacidosis, convulsions, poor feeding, coma, psychomotor delay and mental retardation. Considering that the pathophysiology of MSUD is still poorly understood, in this study we evaluated some parameters of oxidative stress, namely thiobarbituric acid-reactive substances (TBARS), total antioxidant reactivity (TAR) and total antioxidant status (TAS) in plasma from treated MSUD patients presenting high and low plasma leucine levels. We verified a significant increase of TBARS (lipid peroxidation) and a decrease of TAR (capacity to rapidly react with free radicals) in plasma from treated MSUD patients with low and with high plasma levels of leucine compared to the control group. It was also verified that TAS (quantity of tissue antioxidants) was not altered in plasma from treated MSUD patients with low and high blood leucine levels. Finally, we found no correlation between leucine, valine and isoleucine levels with the various parameters of oxidative stress. These results are indicative that increased lipid oxidative damage and decreased antioxidant defenses occur in plasma of MSUD patients and that the accumulating branched-chain amino acids are probably not directly associated to oxidative stress in this disorder.

Oxidative stress is induced in female carriers of X-linked adrenoleukodystrophy.

X-linked adrenoleukodystrophy (X-ALD) is a peroxisomal disease biochemically characterized by the accumulation of very long chain fatty acids (VLCFA), particularly hexacosanoic (C26:0) and tetracosanoic acids (C24:0) in different tissues and in biological fluids and clinically characterized by central and peripheral demyelination and adrenal insufficiency. A considerable number of heterozygotes (HTZ) for X-ALD develop neurological symptoms like spinal cord involvement resembling milder forms of adrenomyeloneuropathy. However, the mechanisms of brain damage in hemizygotes and heterozygotes X-ALD individuals are poorly understood. Considering that oxidative stress was involved in various neurodegenerative disorders and that in a previous study we showed evidence that oxidative stress is probably involved in the pathophysiology of X-ALD symptomatic patients, in the present study we evaluated various oxidative stress parameters, namely thiobarbituric acid-reactive substances (TBA-RS), total antioxidant status (TAS) and total antioxidant reactivity (TAR) in plasma of HTZ individuals for X-ALD. It was observed that female carriers present a significant increase of TBA-RS measurement, indicating a stimulation of lipid peroxidation, as well as a decrease of TAR, reflecting a deficient capacity to rapidly handle an increase of reactive species. These results indicate that oxidative stress is involved in the pathophysiology of heterozygotes for X-ALD.

Concurrent folate treatment prevents Na+,K+-ATPase activity inhibition and memory impairments caused by chronic hyperhomocysteinemia during rat development.

We investigated the hypothesis that folate administration would prevent hyperhomocysteinemia-induced memory deficits and Na(+),K(+)-ATPase activity inhibition. Chronic hyperhomocysteinemia was induced from the 6th to the 28th day of life by subcutaneous injection of homocysteine (0.3-0.6 micromol/g), twice a day; control Wistar rats received the same volume of saline solution (0.9% NaCl). Half of the homocysteine- and saline-treated groups also received intraperitoneal administration of folate (0.011 micromol/g) from the 6th to the 28th day of life. A group of animals was killed 12 h after the last injection, plasma and parietal cortex were collected for biochemical analysis. Another group stayed at Central Animal House until 60th day of life, when the rats were submitted to behavioral testing in water maze or were killed for evaluation of cortical Na(+),K(+)-ATPase activity. Results showed that hyperhomocysteinemia impaired reference memory for platform location, as assessed by fewer crossings to the platform place and increased latency for the first crossing, when compared to controls. In the working memory task homocysteine-treated animals also needed more time to find the platform. We also observed that Na(+),K(+)-ATPase activity was reduced in parietal cortex of hyperhomocysteinemic rats sacrificed 12h after the last injection of homocysteine (29-day-old rats). In contrast, this enzyme was not altered when the rats were sacrificed 31 days after the treatment (60-day-old rats). Hyperhomocysteinemic rats treated with folate had all those impairments prevented, an effect probably related to folate antioxidant properties.

Induction of lipid peroxidation and decrease of antioxidant defenses in symptomatic and asymptomatic patients with X-linked adrenoleukodystrophy.

Patients affected by X-linked adrenoleukodystrophy (X-ALD) present a progressive brain and peripheral demyelination and adrenal cortex insufficiency, associated with accumulation of the very long chain fatty acids (VLCFA) hexacosanoic acid (C26:0) and tetracosanoic acid (C24:0) in different tissues and biological fluids. X-ALD is characterized by heterogeneous clinical phenotypes. Seven clinical variants have been described for this genetic disorder, being the childhood cerebral form (CCER), adrenomyeloneuropathy (AMN) and asymptomatic the most common clinical forms. In a previous work, we showed evidence that oxidative stress is involved in the pathophysiology of X-ALD symptomatic patients. In the present study, we compared oxidative stress parameters, namely thiobarbituric acid reactive substances (TBA-RS) and total antioxidant status (TAS), in plasma from patients with CCER, AMN and in asymptomatic X-ALD patients. It was observed that symptomatic and asymptomatic X-ALD patients presented a significant increase of plasma TBA-RS measurement, indicating a stimulation of lipid peroxidation. Furthermore, lipid peroxidation was higher in AMN, as compared to CCER and asymptomatic patients. We also observed that the total antioxidant defenses (TAS) were decreased in symptomatic but not in asymptomatic X-ALD patients. Therefore, it may be presumed that asymptomatic patients seem to be protected against oxidative stress because of their normal antioxidant defenses and that other factors besides oxidative damage may be responsible for the severity of the symptoms in X-ALD and need to be investigated.

Erythrocyte glutathione peroxidase activity and plasma selenium concentration are reduced in maple syrup urine disease patients during treatment.

Maple syrup urine disease (MSUD) is an inherited disorder caused by a deficiency of the branched-chain alpha-keto acid dehydrogenase complex activity. In the present study we evaluated selenium levels in plasma from MSUD patients at diagnosis and under treatment and the activities of glutathione peroxidase, catalase and superoxide dismutase in erythrocytes from treated patients. We verified that MSUD patients present a significant selenium deficiency at diagnosis, which becomes more pronounced during treatment, as well as a decrease of erythrocyte glutathione peroxidase activity during treatment. In contrast, erythrocyte catalase and superoxide dismutase activities were not altered in these patients. Our present results suggest that the reduction of an important antioxidant enzyme activity may be partially involved in the pathomechanisms of this disorder and that plasma selenium levels must be corrected through dietary supplementation in MSUD patients.

Evidence that oxidative stress is increased in plasma from patients with maple syrup urine disease.

Maple syrup urine disease (MSUD) or branched-chain alpha-keto aciduria (BCKA) is an inherited disorder caused by a deficiency of the branched-chain alpha-keto acid dehydrogenase complex (BCKAD) activity. The blockage of this pathway leads to tissue accumulation of the branched-chain amino acids (BCAA) leucine, isoleucine and valine and their respective keto-acids. The clinical features presented by MSUD patients include ketoacidosis, convulsions, coma, psychomotor delay and mental retardation. The mechanism of brain damage in this disease is still poorly understood. However, an increase in lipid peroxidation in vitro in cerebral cortex of young rats as well as a decrease in the antioxidant defenses has been previously observed. In the present work we evaluated different oxidative stress parameters, named reactive species of thiobarbituric acid (TBARS), total antioxidant reactivity (TAR) and total antioxidant status (TAS) in plasma of MSUD patients in order to evaluate whether oxidative stress is involved in this disorder. We verified a marked increase of plasma TBARS measurements, which is indicative of increased lipid peroxidation, as well as a decrease on plasma TAR reflecting a deficient capacity to efficiently modulate the damage associated with an increased production of reactive species. In contrast, TAS was not changed indicating that the total content of antioxidants in plasma of patients affected by MSUD was not altered. These results suggest that free radical generation is elicited in MSUD and is possibly involved in the pathophysiology of the tissue damage found in this disorder.

Inhibition of the electron transport chain and creatine kinase activity by ethylmalonic acid in human skeletal muscle.

Ethylmalonic aciduria is a common finding in patients affected by short-chain acyl-CoA dehydrogenase (SCAD) deficiency and other diseases characterized by encephalopathy, muscular symptomatology, and lactic acidemia. Considering that the pathophysiological mechanisms of these disorders are practically unknown and that lactic acidosis suggest an impairment of energy production, the objective of the present work was to investigate the in vitro effect of ethylmalonic acid (EMA), at concentrations varying from 0.25 to 5.0 mM, on important parameters of energy metabolism in human skeletal muscle, such as the activities of the respiratory chain complexes and of creatine kinase, which are responsible for most of the ATP produced and transferred inside the cell. We verified that EMA significantly inhibited the activity of complex I-III at concentrations as low as 0.25 mM, complex II-III at 1 mM and higher concentrations, and complex II at the concentration of 5 mM. In contrast, complex IV was not inhibited by the acid. Finally, we observed that the activity of creatine kinase was significantly inhibited by EMA at the concentrations of 1 and 5 mM. These results suggest that EMA compromises energy metabolism in human skeletal muscle. In case the in vitro effects detected in the present study also occur in vivo, it is tempting to speculate that they may contribute, at least in part, to explain the hypotonia/myopathy, as well as the increased concentrations of lactic acid present in the patients affected by illnesses in which EMA accumulates.