Preliminary results of PBA-loaded nanoparticles development and the effect on oxidative stress and neuroinflammation in rats submitted to a chemically induced chronic model of MSUD.

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.

Oxidative stress in phenylketonuria-evidence from human studies and animal models, and possible implications for redox signaling.

Phenylketonuria (PKU) is one of the commonest inborn error of amino acid metabolism. Before mass neonatal screening was possible, and the success of introducing diet therapy right after birth, the typical clinical finds in patients ranged from intellectual disability, epilepsy, motor deficits to behavioral disturbances and other neurological and psychiatric symptoms. Since early diagnosis and treatment became widespread, usually only those patients who do not strictly follow the diet present psychiatric, less severe symptoms such as anxiety, depression, sleep pattern disturbance, and concentration and memory problems. Despite the success of low protein intake in preventing otherwise severe outcomes, PKU's underlying neuropathophysiology remains to be better elucidated. Oxidative stress has gained acceptance as a disturbance implicated in the pathogenesis of PKU. The conception of oxidative stress has evolved to comprehend how it could interfere and ultimately modulate metabolic pathways regulating cell function. We summarize the evidence of oxidative damage, as well as compromised antioxidant defenses, from patients, animal models of PKU, and in vitro experiments, discussing the possible clinical significance of these findings. There are many studies on oxidative stress and PKU, but only a few went further than showing macromolecular damage and disturbance of antioxidant defenses. In this review, we argue that these few studies may point that oxidative stress may also disturb redox signaling in PKU, an aspect few authors have explored so far. The reported effect of phenylalanine on the expression or activity of enzymes participating in metabolic pathways known to be responsive to redox signaling might be mediated through oxidative stress.

In vivo evidence that bezafibrate prevents oxidative stress and mitochondrial dysfunction caused by 3-methylglutaric acid in rat liver.

High urinary excretion and tissue accumulation of 3-methylglutaric acid (MGA) are observed in patients affected by 3-hydroxy-3-methylglutaric (HMGA) and 3-methylglutaconic (MGTA) acidurias. The pathomechanisms underlying the hepatic dysfunction commonly observed in these disorders are not fully elucidated so that we investigated here the effects of intraperitoneal administration of MGA on redox homeostasis, mitochondrial bioenergetics, biogenesis and dynamics in rat liver. The effects of a pre-treatment with the protective compound bezafibrate (BEZ) were also determined. Our data showed that MGA induced lipid peroxidation and altered enzymatic and non-enzymatic antioxidant defenses in liver, indicating redox homeostasis disruption. BEZ prevented most of these alterations induced by MGA. MGA also decreased the activities of the respiratory chain complexes II and IV and increased of II-III, whereas BEZ prevented the alteration in complex II activity. Furthermore, MGA decreased levels of nuclear PGC-1α and Sirt1, and increased levels of AMPKα1 and cytosolic PPARγ, which were blocked by BEZ. MGA augmented the levels of mitofusin-1 and dynamin-related protein 1, suggesting that both fusion and fission mitochondrial processes are enhanced by MGA. BEZ was able to prevent only the changes in mitofusin-1 levels. Collectively, these findings indicate that oxidative stress and mitochondrial dysfunction are mechanisms involved in the hepatic dysfunction found in HMGA and MGTA. It is also presumed that mitochondrial biogenesis stimulation may constitute an attractive approach to reduce MGA toxicity in liver of individuals affected by HMGA and MGTA.

Effects of Fish and Grape Seed Oils as Core of Haloperidol-Loaded Nanocapsules on Oral Dyskinesia in Rats.

Haloperidol is a widely used antipsychotic, despite the severe motor side effects associated with its chronic use. This study was carried out to compare oral dyskinesia induced by different formulations of haloperidol-loaded nanocapsules containing caprylic/capric triglycerides, fish oil or grape seed oil (GSO) as core, as well as free haloperidol. Haloperidol-loaded lipid-core nanocapsules formulations were prepared, physicochemical characterized and administered (0.5 mg kg-1-ip) to rats for 28 days. Oral dyskinesia was evaluated acutely and subchronically and after that cell viability and free radical generation in cortex and substantia nigra. All formulations presented satisfactory physicochemical parameters. Acutely, all formulations were able to prevent oral dyskinesia development in comparison to free haloperidol, except haloperidol-loaded nanocapsules containing GSO, whose effect was only partial. After subchronic treatment, all haloperidol-loaded nanocapsules formulations prevented oral dyskinesia in relation to free drug. Also, haloperidol-loaded nanocapsules containing fish oil and GSO were more effective than caprylic/capric triglycerides nanocapsules and free haloperidol in cell viability preservation and control of free radical generation. Our findings showed that fish oil formulation may be considered as the best formulation of haloperidol-loaded lipid-core nanocapsules, being able to prevent motor side effects associated with chronic use of antipsychotic drugs, as haloperidol.

Neonatal hyperglycemia induces cell death in the rat brain.

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.

Chronic Exposure to ß-Alanine Generates Oxidative Stress and Alters Energy Metabolism in Cerebral Cortex and Cerebellum of Wistar Rats.

ß-Alanine occurs naturally in the human central nervous system and performs different functions. It can act as either a neurotransmitter or a neuromodulator, depletion of taurine levels and competitive antagonist of γ-aminobutyric acid (GABA). The ß-amino acid accumulation exerts an important biological function as delay in brain development, oxidative stress and disturbances in energy metabolism, characterized as an inborn error of metabolism classified as ß-alaninemia. We evaluated the effects of the chronic administration of ß-alanine on some parameters of oxidative stress and enzymes of energy metabolism in cerebral cortex and cerebellum of 21-day-old Wistar rats. The animals received peritoneal injections of ß-alanine (300 mg/kg of body weight), and the controls received the same volume (10 µl/g of body weight) of saline solution (NaCl 0.9%), twice a day at 12-h interval, from the 7th to the 21st postpartum day. We observed that ß-amino acid was able to increase the levels of reactive oxygen species (ROS) in the two tissues; however, only in cerebral cortex total content of sulfhydryl was increased. ROS are possibly acting on antioxidant enzymes glutathione peroxidase (GPx) (cerebral cortex and cerebellum) and superoxide dismutase (SOD) (cerebellum) inhibiting their activities. We also evaluated the activities of enzymes of the phosphoryl transfer network, where we observed an increase in hexokinase and cytosolic creatine kinase (Cy-CK) activities; however, it decreased glyceraldehyde 3-phosphate dehydrogenase (GAPDH), pyruvate kinase (PK) and lactate dehydrogenase (LDH) activities, in both tissues. Besides, the ß-alanine administration increased the activities of complex II, complex IV and succinate dehydrogenase (SDH). Those results suggest that the chronic administration of ß-alanine causes cellular oxidative damage, significantly changing the energy metabolism.

Evaluation of Oxidative Stress Parameters and Energy Metabolism in Cerebral Cortex of Rats Subjected to Sarcosine Administration.

Sarcosine is an N-methyl derivative of the amino acid glycine, and its elevation in tissues and physiological fluids of patients with sarcosinemia could reflect a deficient pool size of activated 1-carbon units. Sarcosinemia is a rare inherited metabolic condition associated with mental retardation. In the present study, we investigated the acute effect of sarcosine and/or creatine plus pyruvate on some parameters of oxidative stress and energy metabolism in cerebral cortex homogenates of 21-day-old Wistar rats. Acute administration of sarcosine induced oxidative stress and diminished the activities of adenylate kinase, GAPDH, complex IV, and mitochondrial and cytosolic creatine kinase. On the other hand, succinate dehydrogenase activity was enhanced in cerebral cortex of rats. Moreover, total sulfhydryl content was significantly diminished, while DCFH oxidation, TBARS content, and activities of SOD and GPx were significantly enhanced by acute administration of sarcosine. Co-administration of creatine plus pyruvate was effective in the prevention of alterations provoked by sarcosine administration on the oxidative stress and the enzymes of phosphoryltransfer network. These results indicate that acute administration of sarcosine may stimulate oxidative stress and alter the energy metabolism in cerebral cortex of rats. In case these effects also occur in humans, they may contribute, along with other mechanisms, to the neurological dysfunction of sarcosinemia, and creatine and pyruvate supplementation could be beneficial to the patients.

Chemically induced acute model of sarcosinemia in wistar rats.

In the present study, we developed an acute chemically induced model of sarcosinemia in Wistar rats. Wistar rats of 7, 14 and 21 postpartum days received sarcosine intraperitoneally in doses of 0.5 mmol/Kg of body weight three time a day at intervals of 3 h. Control animals received saline solution (NaCl 0.85 g%) in the same volume (10 mL/Kg of body weight). The animals were killed after 30 min, 1, 2, 3 or 6 h after the last injection and the brain and the blood were collected for sarcosine measurement. The results showed that plasma and brain sarcosine concentrations achieved levels three to four times higher than the normal levels and decreased in a time-dependent way, achieving normal levels after 6 hours. Considering that experimental animal models are useful to investigate the pathophysiology of human disorders, our model of sarcosinemia may be useful for the research of the mechanisms of neurological dysfunction caused by high tissue sarcosine levels.

Phenylalanine induces oxidative stress and decreases the viability of rat astrocytes: possible relevance for the pathophysiology of neurodegeneration in phenylketonuria.

The aim of this study was to investigate the effects of phenylalanine on oxidative stress and some metabolic parameters in astrocyte cultures from newborn Wistar rats. Astrocytes were cultured under four conditions: control (0.4 mM phenylalanine concentration in the Dulbecco's Modified Eagle Medium (DMEM) solution), Phe addition to achieve 0.5, 1.0 or 1.5 mM final phenylalanine concentrations. After 72 h the astrocytes were separated for the biochemical measurements. Overall measure of mitochondrial function by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and cell viability measured by lactate dehydrogenase (LDH) assays indicated that phenylalanine induced cell damage at the three concentrations tested. The alteration on the various parameters of oxidative stress indicated that phenylalanine was able to induce free radicals production. Therefore, our results strongly suggest that Phe at concentrations usually found in PKU induces oxidative stress and consequently cell death in astrocytes cultures. Considering the importance of the astrocytes for brain function, it is possible that these astrocytes alterations may contribute to the brain damage found in PKU patients.

Voluntary Exercise Prevents Oxidative Stress in the Brain of Phenylketonuria Mice.

BACKGROUND: High phenylalanine levels in phenylketonuria (PKU) have been associated with brain oxidative stress and amino acid imbalance. Exercise has been shown to improve brain function in hyperphenylalaninemia and neurodegenerative diseases. This study aimed to verify the effects of exercise on coordination and balance, plasma and brain amino acid levels, and brain oxidative stress markers in PKU mice. METHODS: Twenty wild-type (WT) and 20 PAH(enu2) (PKU) C57BL/6 mice were placed in cages with (exercise, Exe) or without (sedentary, Sed) running wheels during 53 days. At day 43, a balance beam test was performed. Plasma and brain were collected for analyses of amino acid levels and the oxidative stress parameters superoxide dismutase (SOD) activity, sulfhydryl and reduced glutathione (GSH) contents, total radical-trapping antioxidant potential (TRAP), and total antioxidant reactivity (TAR). RESULTS: SedPKU showed poor coordination (p < 0.001) and balance (p < 0.001), higher plasma and brain phenylalanine (p < 0.001), and increased brain oxidative stress (p < 0.05) in comparison to SedWT. ExePKU animals ran less than ExeWT (p = 0.018). Although no improvement was seen in motor coordination and balance, exercise in PKU restored SOD, sulfhydryl content, and TRAP levels to controls. TAR levels were increased in ExePKU in comparison to SedPKU (p = 0.012). Exercise decreased plasma and brain glucogenic amino acids in ExePKU, but did not change plasma and brain phenylalanine in both WT and PKU. CONCLUSIONS: Exercise prevents oxidative stress in the brain of PKU mice without modifying phenylalanine levels. Hence, exercise positively affects the brain, demonstrating its value as an intervention to improve brain quality in PKU.

L-carnitine Prevents Oxidative Stress in the Brains of Rats Subjected to a Chemically Induced Chronic Model of MSUD.

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.

Investigation of inflammatory profile in MSUD patients: benefit of L-carnitine supplementation.

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.

L-Carnitine supplementation decreases DNA damage in treated MSUD patients.

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.

Urinary biomarkers of oxidative damage in Maple syrup urine disease: the L-carnitine role.

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.

Neonatal hyperglycemia induces oxidative stress in the rat brain: the role of pentose phosphate pathway enzymes and NADPH oxidase.

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.

Creatine and pyruvate prevent the alterations caused by tyrosine on parameters of oxidative stress and enzyme activities of phosphoryltransfer network in cerebral cortex of Wistar rats.

Tyrosine accumulates in inborn errors of tyrosine catabolism, especially in tyrosinemia type II. In this disease caused by tyrosine aminotransferase deficiency, eyes, skin, and central nervous system disturbances are found. In the present study, we investigated the chronic effect of tyrosine methyl ester (TME) and/or creatine plus pyruvate on some parameters of oxidative stress and enzyme activities of phosphoryltransfer network in cerebral cortex homogenates of 21-day-old Wistar. Chronic administration of TME induced oxidative stress and altered the activities of adenylate kinase and mitochondrial and cytosolic creatine kinase. Total sulfhydryls content, GSH content, and GPx activity were significantly diminished, while DCFH oxidation, TBARS content, and SOD activity were significantly enhanced by TME. On the other hand, TME administration decreased the activity of CK from cytosolic and mitochondrial fractions but enhanced AK activity. In contrast, TME did not affect the carbonyl content and PK activity in cerebral cortex of rats. Co-administration of creatine plus pyruvate was effective in the prevention of alterations provoked by TME administration on the oxidative stress and the enzymes of phosphoryltransfer network, except in mitochondrial CK, AK, and SOD activities. These results indicate that chronic administration of TME may stimulate oxidative stress and alter the enzymes of phosphoryltransfer network in cerebral cortex of rats. In case this also occurs in the patients affected by these disorders, it may contribute, along with other mechanisms, to the neurological dysfunction of hypertyrosinemias, and creatine and pyruvate supplementation could be beneficial to the patients.

Acute exercise in treated phenylketonuria patients: Physical activity and biochemical response.

BACKGROUND: In phenylketonuria, dietary treatment prevents most of the severe brain disease. However, patients have to follow a diet restricted in several natural components, what may cause decreased bone density and obesity. Exercise is known to improve both mental functioning and bone density also avoiding obesity, and could optimize aspects of central and peripheral outcome, regardless changes in phenylalanine (Phe) levels. However, the acute effects of exercise on metabolic parameters in phenylketonuria patients are unknown and thereby long-term adaptations are unclear. Therefore, this study aimed to evaluate patients' basal metabolic rate (BMR), and their acute response to an aerobic exercise session on plasma concentrations of Phe, tyrosine (Tyr), and branched-chain amino acids (BCAA), as well as metabolic and hormonal responses. METHODS: Five early- and four late diagnosed phenylketonuria patients aged 21 ± 4 years and 17 sex-, age-, and BMI-matched controls were evaluated for BMR, peak oxygen consumption (VO2peak) and plasma amino acid, glucose, lipid profile and hormonal levels. At least one week later, participants performed a 30-min aerobic exercise session (intensities individually calculated using the VO2peak results). Blood samples were collected in fasted state (moment 1, M1) and immediately after a small breakfast, which included the metabolic formula for patients but not for controls, and the exercise session (moment 2, M2). RESULTS: Phenylketonuria patients and controls showed similar BMR and physical capacities. At M1, patients presented higher Phe concentration and Phe/Tyr ratio; and lower levels of BCAA and total cholesterol than controls. Besides that, poorly controlled patients tended to stay slightly below the prescribed VO2 during exercise. Both patients and controls showed increased levels of total cholesterol and LDL at M2 compared with M1. Only controls showed increased levels of Tyr, lactate, and HDL; and decreased Phe/Tyr ratio and glucose levels at M2 compared to values at M1. CONCLUSIONS: Acute aerobic exercise followed by a Phe-restricted breakfast did not change Phe concentrations in treated phenylketonuria patients, but it was associated with decreased Phe/Tyr only in controls. Further studies are necessary to confirm our results in a higher number of patients.

Diabetic encephalopathy-related depression: experimental evidence that insulin and clonazepam restore antioxidant status in rat brain.

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.

Prevention of DNA damage by L-carnitine induced by metabolites accumulated in maple syrup urine disease in human peripheral leukocytes in vitro.

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.

Respostas de lactato, esforço percebido, frequência cardíaca, triptofano, prolactina e ácidos graxos à série de natação na velocidade crítica / Responses of lactate, perceived exertion, heart rate, tryptophan, prolactin and fatty acid in swimming series held in critical speed / Respuestas de lactato, esfuerzo percibido, frecuencia cardíaca, triptófano, prolactina y ácidos grasos en serie de natación en la velocidad crítica

O estudo avaliou, na intensidade de 100% da velocidade crítica (VC), o comportamento de concentração de lactato sanguíneo ([LA]), esforço percebido (EP), frequência cardíaca (FC), concentrações plasmáticas de triptofano [TRP], de prolactina ([PRL]) e de ácidos graxos livres ([AGL]). Catorze nadadores realizaram dois protocolos distintos: 1) repetições de 200 e 400 m, em máxima intensidade (V200 e V400) para a determinação da VC; 2) série VC (repetições de 400 m), com intervalos de 40 s. Os principais resultados foram: (1) [TRP] e [AGL] não apresentaram diferenças entre repouso e exaustão (p > 0,05); (2) aumento da [PRL], da [LA], da FC e do EP (p < 0,05) ao longo da série VC. Assim o aumento da [PRL] pode indicar manifestação de fadiga central na intensidade correspondente à VC.

The study assessed, at the intensity of 100% of the critical speed (CS), the behavior of blood lactate concentration ([La]), rating of perceived exertion (RPE), heart rate (HR), plasma concentrations of tryptophan [TRP] of prolactin ([PRL]) and free fatty acids ([FFA]). Fourteen swimmers performed two protocols: 1) trials of 200 and 400 m at maximum intensity (V200 and V400) for the CS, 2) CS series (trials of 400 m), and rest intervals of 40 s. The main results were: (1) [TRP] and [FFA] did not differ between rest and exhaustion (p> 0.05), (2) increased [PRL], the [La], HR and RPE (p <0.05) throughout the series CS. Thus the increase in [PRL] may indicate manifestation of central fatigue in intensity corresponding to the CS.

Este estudio evaluó, en la intensidad del 100% de la velocidad crítica (CV), el comportamiento de la concentración de lactato en la sangre ([LA]), esfuerzo percibido (PE), frecuencia cardíaca (FC), concentración plasmática de triptófano [TRP], prolactina ([PRL]) y de ácidos grasos libres ([AGL]). Catorce nadadores realizaron dos protocolos: 1) repeticiones de 200 y 400 m en máxima intensidad (V200 y V400) para la determinación de la CV, 2) serie VC (repeticiones de 400 m), con intervalos de 40 s. Los principales resultados fueron: (1) [TRP] y [FFA] no fueran diferentes entre el descanso y el agotamiento (p> 0,05), (2) mayores [PRL], [LA], FC y EP (p <0,05) a lo largo de la serie VC. Por lo tanto, el aumento de [PRL] pude indicar manifestación de fatiga central en la intensidad correspondiente a la VC.