Oral glutamine supplementation relieves muscle loss in immobilized rats, altering p38MAPK and FOXO3a signaling pathways.

BACKGROUND: Skeletal muscle synthesizes, stores, and releases body L-glutamine (GLN). Muscle atrophy due to disabling diseases triggers the activation of proteolytic and pro-apoptotic cell signaling, thus impairing the body's capacity to manage GLN content. This situation has a poor therapeutic prognosis. OBJECTIVE: Evaluating if oral GLN supplementation can attenuate muscle wasting mediated by elevated plasma cortisol and activation of caspase-3, p38MAPK, and FOXO3a signaling pathways in soleus and gastrocnemius muscles of rats submitted to 14-day bilateral hindlimbs immobilization. METHODS: Animals were randomly distributed into six groups: non-immobilized rats (Control), control orally supplemented with GLN (1 g kg-1) in solution with L-alanine (ALA: 0.61 g kg-1; GLN+ALA), control orally supplemented with dipeptide L-alanyl-L-glutamine (DIP; 1.49 g kg-1), hindlimbs immobilized rats (IMOB), IMOB orally GLN+ALA supplemented (GLN+ALA-IMOB), and IMOB orally DIP supplemented (DIP-IMOB). Plasma and muscle GLN concentration, plasma cortisol level, muscle caspase-3 activity, muscle p38MAPK and FOXO3a protein content (total and phosphorylated forms), and muscle cross-sectional area (CSA) were measured. RESULTS: Compared to controls, IMOB rats presented: a) increased plasma cortisol levels; b) decreased plasma and muscle GLN concentration; c) increased muscle caspase-3 activity; d) increased total and phosphorylated p38MAPK protein content; e) increased FOXO3a and decreased phosphorylated FOXO3a protein content; f) reduced muscle weight and CSA befitting to atrophy. Oral supplementation with GLN+ALA and DIP was able to significantly attenuate these effects. CONCLUSIONS: These findings attest that oral GLN supplementation in GLN+ALA solution or DIP forms attenuates rats' skeletal muscle mass wasting caused by disuse-mediated muscle atrophy.

ß-Cyclodextrins alter the energy metabolism-related enzyme activities in rats.

Although widely used in medicine, separation technology, and other fields, the effects of cyclodextrins on the activities of phosphoryl transfer enzymes have not been previously evaluated. In vivo studies evaluated the function of cyclodextrins as active compounds. Despite the use of cyclodextrins as active compounds, the effects of cyclodextrins on hepatic and renal tissues remain to be fully elucidated. The primary objective of this study was to evaluate the effects of ß- cyclodextrins, methyl-ß-cyclodextrin (M-ß- cyclodextrins), and (2-hydroxypropyl)-ß-cyclodextrin (HP-ß-cyclodextrins) on enzyme activities regulating the maintenance of energy homeostasis in the kidney and liver tissues in relation to toxicity. Serum levels of liver and kidney markers were measured, and oxidative stress parameters were assessed. After 60-day treatments, we observed that the administration of ß-cyclodextrins and M-ß-cyclodextrins inhibited the hepatic activity of pyruvate kinase, an irreversible enzyme within the glycolytic pathway. Additionally, administration of HP-ß-cyclodextrins inhibited creatine kinase activity and increased the total sulfhydryl content in kidneys. Here, we demonstrated for the first time that ß-cyclodextrins, M-ß-cyclodextrins, and HP-ß-cyclodextrins cause bioenergetic dysfunction in renal and hepatic tissues. These findings suggest that understanding the balance between cyclodextrins' efficacy and adverse effects is essential for better accepting their use in medicine.

Lipopolysaccharide impairs neurodevelopment and induces changes in astroglial reactivity, antioxidant defenses and bioenergetics in the cerebral cortex of neonatal rats.

Neonates have an immature immune system, which increases their vulnerability to infectious agents and inflammatory insults. The administration of the immunostimulatory agent lipopolysaccharide (LPS) has been shown to induce the expression of pro-inflammatory cytokines and cause behavior alterations in rodents at different ages. However, the effects of LPS administration during the neonatal period and its consequences during immune system maturation remain to be elucidated. We showed here that a single intraperitoneal administration of LPS in rats on postnatal day (PND) 7 caused early and variable alterations in TNF-α, S100B and GFAP levels in the cerebral cortex, CSF and serum of the animals, indicating long-term induction of neuroinflammation and astroglial reactivity. However, on PND 21, only GFAP levels were increased by LPS. Additionally, LPS induced oxidative stress and altered energy metabolism enzymes in the cerebral cortex on PND 21, and caused neurodevelopment impairment over time. These data suggest that neuroinflammation induction during the neonatal period induces glial reactivity, oxidative stress and bioenergetic disruption that may lead to neurodevelopment impairment and cognitive deficit in adult life.

Anabolic-androgenic steroids impair mitochondrial function and redox status in the heart and liver of mice.

Supraphysiological doses of anabolic-androgenic steroids (AAS) may cause long-term functional abnormalities, particularly in the heart and liver, which may only represent the later-stage of the cumulative damage caused by dysfunctional organelles. We investigated whether mid-term supraphysiological doses of Testosterone and Nandrolone impair mitochondrial Ca2+ and membrane potential (ΔΨm) dynamics, and redox machinery in the heart and liver of mice. CF1 albino mice were treated daily with 15 mg/kg of Nandrolone (ND) or Testosterone (T), or oil (vehicle) for 19 days. Preparations enriched in mitochondria from the heart or liver were used to perform assays of Ca2+ influx/efflux, ΔΨm, and H2O2 production. ND significantly impaired mitochondrial Ca2+ influx in the heart, and ΔΨm in both organs. ND and T increased H2O2 levels in the heart and liver relative to controls. Also, ND increased oxidative damage to lipids and proteins (TBARS and carbonyls) in the heart, and both AAS decreased glutathione peroxidase activity in the heart and liver. In summary, supraphysiological doses of ND, and in a lesser extend T, impaired mitochondrial Ca2+ influx and ΔΨm, and redox homeostasis being early mechanistic substrates for inducing heart and liver tissue damage.

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.

Wide field scanning by optical fluorescence of oral squamous cell carcinoma (SCC): case report / Fotoevidenciação de campo amplo por fluorescência óptica de carcinoma de células escamosas (CEC) oral: estudo de casos

ABSTRACT Optical fluorescence detection aims to identify precursor lesions, little noticeable to the human eye, and oral cancer. Squamous cell carcinoma or spinocellular carcinoma is a malignant neoplasm that affects the mouth more. In this article, two clinical cases are analyzed, treated with the use of two types of equipment, namely: the photoevidenciation by optical fluorescence of light-emitting violet wavelength of 405nm, power of 100mW, which is luminous radiation, not Ionizing and in the adjuvant treatment, we used low-power laser therapy, power 100mW, with two wavelengths of 808nm infrared, for pain relief, and the red 660nm, for oral mucositis. In Photodynamic therapy, the Photosensitizing Chimiolux® (methylene blue) was used to control Candida albicans. From these cases, we discuss how a more assertive diagnostic hypothesis can save a life and save time, resources, and efforts for the correct diagnosis of the pathology compared to a biopsy and histopathology negative for neoplasia. We conclude that optical fluorescence has excellent social relevance due to its potential to help the professional not specialized in the establishment of early diagnosis of oral cancer. Early diagnosis improves the rates of death caused by this carcinoma, which would extend the post-diagnosis survival and decrease the financial and emotional costs for the patient and family.

RESUMO A detecção óptica por fluorescência visa identificar lesões precursoras, pouco perceptíveis ao olho humano, e do câncer oral. O carcinoma de células escamosas ou carcinoma espinocelular (CEC), é a denominação de uma neoplasia maligna que acomete mais a boca. Neste artigo, são analisados dois casos clínicos, tratados com a utilização de dois equipamentos, a saber: o de fotoevidenciação por fluorescência óptica de emissão de luz violeta de comprimento de onda de 405nm, potência de 100mW, que é radiação luminosa não ionizante; e no tratamento coadjuvante, utilizou-se a laserterapia de baixa potência, potência 100mW, com dois comprimentos de onda de infravermelho 808nm, para alívio de dor, e o vermelho 660nm, para as mucosites orais. Na terapia fotodinâmica, empregou-se o fotossensibilizador Chimiolux® (azul de metileno) para controle de Candida albicans. A partir desses casos, discutimos como uma hipótese diagnóstica mais assertiva pode salvar uma vida e poupar tempo, recursos e esforços para o correto diagnóstico da patologia se comparado a uma biópsia e histopatológico negativo para neoplasia. Por fim, concluímos que a fluorescência óptica tem grande relevância social devido a seu potencial de auxiliar o profissional não especialista no estabelecimento de um diagnóstico precoce do câncer oral, melhorando os índices de óbito causados por esse carcinoma, o que estenderia a sobrevida pós-diagnóstico e diminuiria os custos financeiros e emocionais do paciente e familiares.

Ibuprofen during gestation prevents some changes in physical and reflex development in offspring in a model of hyperleucinemia and maternal inflammation.

Maple Syrup Urine Disease (MSUD) is caused by a severe deficiency in the branched-chain ketoacid dehydrogenase complex activity. Patients MSUD accumulate the branched-chain amino acids leucine (Leu), isoleucine, valine in blood, and other tissues. Leu and/or their branched-chain α-keto acids are linked to neurological damage in MSUD. When immediately diagnosed and treated, patients develop normally. Inflammation in MSUD can elicit a metabolic decompensation crisis. There are few cases of pregnancy in MSUD women, and little is known about the effect of maternal hyperleucinemia on the neurodevelopment of their babies. During pregnancy, some intercurrences like maternal infection or inflammation may affect fetal development and are linked to neurologic diseases. Lipopolysaccharide is widely accepted as a model of maternal inflammation. We analyzed the effects of maternal hyperleucinemia and inflammation and the possible positive impact the use of ibuprofen in Wistar rats on a battery of physics (ear unfolding, hair growing, incisors eruption, eye-opening, and auditive channel opening) and neurological reflexes (palmar grasp, surface righting, negative geotaxis, air-righting, and auditory-startle response) maturation parameters in the offspring. Maternal hyperleucinemia and inflammation delayed some physical parameters and neurological reflexes, indicating that both situations may be harmful to fetuses, and ibuprofen reversed some settings.

Resveratrol and resveratrol-hydroxypropyl-ß-cyclodextrin complex recovered the changes of creatine kinase and Na+, K+-ATPase activities found in the spleen from streptozotocin-induced diabetic rats.

Type 1 diabetes (T1D) is the result of the selective destruction of the pancreatic ß-cells by T cells of the immune system. Although spleen is a secondary lymphoid organ, it is also involved in the T1D pathogenesis. However, the alterations in a variety of cellular processes of this disease need to be further understood. We aimed to analyze the benefits of resveratrol, and its complexed form on diabetic complications in the spleen of rats. To this end, we investigated important enzymes of phosphoryl transfer network, and Na+, K+-ATPase activity. Wistar rats were divided into non-diabetic groups: Control, Ethanol, Resveratrol, Hydroxypropyl-ß-cyclodextrin, Resveratrol-hydroxypropyl-ß-cyclodextrin, and diabetic groups with the same treatments. Diabetes was induced by a single dose of 60 mg/kg of streptozocin intraperitoneally, and treatments by intragastric gavage once daily for 60 days. Hyperglycemia reduced creatine kinase activity, which was reversed by the administration of resveratrol. Na+, K+-ATPase activity was greatly affected, but it was reversed by resveratrol and resveratrol-hydroxypropyl-ß-cyclodextrin. This suggest an energetic imbalance in the spleen of diabetic rats, and in case this also occurs in the diabetic patients, it is possible that resveratrol supplementation could be beneficial to the better functioning of the spleen in diabetic patients.

Oral glutamine supplementation attenuates inflammation and oxidative stress-mediated skeletal muscle protein content degradation in immobilized rats: Role of 70 kDa heat shock protein.

Skeletal muscle disuse results in myofibrillar atrophy and protein degradation, via inflammatory and oxidative stress-mediated NF-kB signaling pathway activation. Nutritional interventions, such as l-glutamine (GLN) supplementation have shown antioxidant properties and cytoprotective effects through the modulation on the 70-kDa heat shock protein (HSP70) expression. However, these GLN-mediated effects on cell signaling pathways and biochemical mechanisms that control the myofibrillar protein content degradation in muscle disuse situations are poorly known yet. This study investigated the effects of oral GLN plus l-alanine (ALA; GLN â€‹+ â€‹ALA-solution) supplementation, either in their free or dipeptide (L-alanyl-l-glutamine-DIP) form, on GLN-glutathione (GSH) axis and cytoprotection mediated by HSP70 protein expression in the slow-twitch soleus and fast-twitch gastrocnemius skeletal muscle of rats submitted to 14-days of hindlimb immobilization-induced disuse muscle atrophy. Forty-eight Wistar rats were distributed into 6 groups: hindlimb immobilized (IMOB group) and hindlimb immobilized orally supplemented with either GLN (1 g kg-1) plus ALA (0.61 g kg-1) â€‹(GLN â€‹+ â€‹ALA-IMOB group) or 1.49 â€‹g â€‹kg-1 of DIP (DIP-IMOB group) and; no-immobilized (CTRL) and no-immobilized supplemented GLN â€‹+ â€‹ALA and DIP baselines groups. All animals, including CTRL and IMOB rats (water), were supplemented via intragastric gavage for 14 days, concomitantly to immobilization period. Plasma and muscle GLN levels, lipid (thiobarbituric acid reactive substances-TBARS) and protein (carbonyl) peroxidation, erythrocyte concentration of reduced GSH and GSH disulfide (GSSG), plasma and muscle pro-inflammatory TNF-α levels, muscle IKKα/ß-NF-kB signaling pathway and, the myofibrillar protein content (MPC) were measured. The MPC was significantly lower in IMOB rats, compared to CTRL, GLN â€‹+ â€‹ALA, and DIP animals (p â€‹< â€‹0.05). This finding was associated with reduced plasma and muscle GLN concentration, equally in IMOB animals. Conversely, both GLN â€‹+ â€‹ALA and DIP supplementation restored plasma and muscle GLN levels, which equilibrated GSH and intracellular redox status (GSSG/GSH ratio) in erythrocytes and skeletal muscle even as, increased muscle HSP70 protein expression; attenuating oxidative stress and TNF-α-mediated NF-kB pathway activation, fact that reverberated on reduction of MPC degradation in GLN â€‹+ â€‹ALA-IMOB and DIP-IMOB animals (p â€‹< â€‹0.05). In conclusion, the findings shown herein support the oral GLN â€‹+ â€‹ALA and DIP supplementations as a therapeutic and effective nutritional alternative to attenuate the deleterious effects of the skeletal muscle protein degradation induced by muscle disuse.

Creatine nanoliposome reverts the HPA-induced damage in complex II-III activity of the rats' cerebral cortex.

Phenylketonuria (PKU) is a metabolic disorder accumulating phenylalanine (Phe) and its metabolites in plasma and tissues of the patients. Regardless of the mechanisms, which Phe causes brain impairment, are poorly understood, energy deficit may have linked to the neurotoxicity in PKU. It is widely recognized that creatine is involved in maintaining of cerebral energy homeostasis. Because of this, in a previous work, we incorporated it into liposomes and this increased the concentration of creatine in the cerebral cortex. Here, we examined the effect of creatine nanoliposomes on parameters of oxidative stress, enzymes of phosphoryl transfer network, and activities of the mitochondrial respiratory chain complexes (RCC) in the cerebral cortex of young rats chemically induced hyperphenylalaninemia (HPA). HPA was induced with L-phenylalanine (5.2 µmol/g body weight; twice a day; s.c.), and phenylalanine hydroxylase inhibitor, α-methylphenylalanine (2.4 µmol/g body weight; once a day; i.p.), from the 7th to the 19th day of life. HPA reduced the activities of pyruvate kinase, creatine kinase, and complex II + III of RCC in the cerebral cortex. Creatine nanoliposomes prevented the inhibition of the activities of the complexes II + III, caused by HPA, and changes oxidative profile in the cerebral cortex. Considering the importance of the mitochondrial respiratory chain for brain energy production, our results suggesting that these nanoparticles protect against neurotoxicity caused by HPA, and can be viable candidates for treating patients HPA.

Creatine plus pyruvate supplementation prevents oxidative stress and phosphotransfer network disturbances in the brain of rats subjected to chemically-induced phenylketonuria.

Phenylketonuria (PKU) is the most common inborn error of amino acid metabolism. Usually diagnosed within the first month of birth, it is essential that the patient strictly follow the dietary restriction of natural protein intake. Otherwise, PKU impacts the development of the brain severely and may result in microcephaly, epilepsy, motor deficits, intellectual disability, and psychiatric and behavioral disorders. The neuropathology associated with PKU includes defects of myelination, insufficient synthesis of monoamine neurotransmitters, amino acid imbalance across the blood-brain barrier, and involves intermediary metabolic pathways supporting energy homeostasis and antioxidant defenses in the brain. Considering that the production of reactive oxygen species (ROS) is inherent to energy metabolism, we investigated the association of creatine+pyruvate (Cr + Pyr), both energy substrates with antioxidants properties, as a possible treatment to mitigate oxidative stress and phosphotransfer network impairment elicited in the brain of young Wistar rats by chemically-induced PKU. We induced PKU through the administration of α-methyl-L-phenylalanine and phenylalanine for 7 days, with and without Cr + Pyr supplementation, until postpartum day 14. The cotreatment with Cr + Pyr administered concurrently with PKU induction prevented ROS formation and part of the alterations observed in antioxidants defenses and phosphotransfer network enzymes in the cerebral cortex, hippocampus, and cerebellum. If such prevention also occurs in PKU patients, supplementing the phenylalanine-restricted diet with antioxidants and energetic substrates might be beneficial to these patients.

Testosterone Administration after Traumatic Brain Injury Reduces Mitochondrial Dysfunction and Neurodegeneration.

Traumatic brain injury (TBI) increases Ca2+ influx into neurons and desynchronizes mitochondrial function leading to energy depletion and apoptosis. This process may be influenced by brain testosterone (TS) levels, which are known to decrease after TBI. We hypothesized that a TS-based therapy could preserve mitochondrial neuroenergetics after TBI, thereby reducing neurodegeneration. C57BL/6J mice were submitted to sham treatment or severe parasagittal controlled cortical impact (CCI) and were subcutaneously injected with either vehicle (VEH-SHAM and VEH-CCI) or testosterone cypionate (15 mg/kg, TS-CCI) for 10 days. Cortical tissue homogenates ipsilateral to injury were used for neurochemical analysis. The VEH-CCI group displayed an increased Ca2+-induced mitochondrial swelling after the addition of metabolic substrates (pyruvate, malate, glutamate, succinate, and adenosine diphosphate [PMGSA]). The addition of Na+ stimulated mitochondrial Ca2+ extrusion through Na+/Ca2+/Li+ exchanger (NCLX) in VEH-SHAM and TS-CCI, but not in the VEH-CCI group. Reduction in Ca2+ efflux post-injury was associated with impaired mitochondrial membrane potential formation/dissipation, and decreased mitochondrial adenosine triphosphate (ATP)-synthase coupling efficiency. Corroborating evidence of mitochondrial uncoupling was observed with an increase in H2O2 production post-injury, but not in superoxide dismutase (SOD2) protein levels. TS administration significantly reduced these neuroenergetic alterations. At molecular level, TS prevented the increase in pTauSer396 and alpha-Spectrin fragmentation by the Ca2+dependent calpain-2 activation, and decreased both caspase-3 activation and Bax/BCL-2 ratio, which suggests a downregulation of mitochondrial apoptotic signals. Search Tool for the Retrieval of Interacting Genes/Proteins database provided two distinct gene/protein clusters, "upregulated and downregulated," interconnected through SOD2. Therefore, TS administration after a severe CCI improves the mitochondrial Ca2+extrusion through NCLX exchanger and ATP synthesis efficiency, ultimately downregulating the overexpression of molecular drivers of neurodegeneration.

Effects of bovine enterovirus and type 1 diabetes on liver and kidney pyruvate kinase activity in an animal model

Type 1 diabetes (T1D) is an autoimmune disease characterized by the selective destruction of pancreatic beta cells. In addition to genetic factors, enteroviruses have been considered the main environmental factor involved in this pathology. Therefore, the objective of this study was to evaluate the effects of streptozotocin-induced diabetes and bovine enterovirus (BEV) on liver and kidney pyruvate kinase activity in rats. Fourteen male Wistar rats were divided in three groups: control, diabetes and a third group, which was fed with water experimentally contaminated by BEV. Increased blood glucose levels were found in both diabetes and enterovirus groups, whereas there were no alterations in the lipid profile. A reduced pyruvate kinase activity was observed in the liver and kidney of animals from diabetes and enterovirus groups. Under our experimental conditions, the ingestion of water experimentally contaminated by BEV induced alterations in glycaemia, and also interfered in the pyruvate kinase activity in liver and kidney of the rats, which might be one of the possible mechanisms involved in the T1D development.

Evaluation of hematological, biochemical parameters and thiol enzyme activity in chrome plating workers.

The most commonly used solution in chrome plating bath is chromic acid (hexavalent Cr), and a considerable amount of mists is released into the air and consequently produce hazards to workers. Thus, the aim of this study was to evaluate whether the biomarker of exposure to metals, specially Cr levels, presents associations with hematological and biochemical parameters and if they can alter the activity of enzymes that contain thiol groups such as pyruvate kinase, creatine kinase, adenylate kinase, and δ-aminolevulinate dehydratase. Fifty male chrome plating workers were used for exposed group and 50 male non-exposed workers for control group. For that, biological monitoring was performed through quantification of metals on total blood and urine by inductively coupled plasma mass spectrometry (ICP-MS) and enzyme activity was performed by spectrometry in erythrocytes. In addition, chromium levels in water was quantified and ecotoxicology assay was performed with Allium cepa test. The results demonstrated that blood and urinary chromium levels in exposed group were higher than the control group (p < 0.0001). Furthermore, decreased activity of enzymes was found in those that contain thiol groups from exposed group when compared with the control group (p < 0.001). The water analysis did not present a statistical difference between control and exposed groups (p > 0.05), demonstrating that water did not seem to be the source of contamination. In summary, our findings indicated some toxicology effects observed in the exposed group, such as thiol enzyme inhibition, mainly associated with occupational exposure in chrome plating and besides the presence of other metals, and Cr demonstrated to influence the activity of the enzymes analyzed in this research.

Thiol/disulfide status regulates the activity of thiol-containing kinases related to energy homeostasis in rat kidney

ABSTRACT Considering that thiol-containing enzymes like kinases are critical for several metabolic pathways and energy homeostasis, we investigated the effects of cystine dimethyl ester and/or cysteamine administration on kinases crucial for energy metabolism in the kidney of Wistar rats. Animals were injected twice a day with 1.6 µmol/g body weight cystine dimethyl ester and/or 0.26 µmol/g body weight cysteamine from the 16th to the 20th postpartum day and euthanized after 12 hours. Pyruvate kinase, adenylate kinase, creatine kinase activities and thiol/disulfide ratio were determined. Cystine dimethyl ester administration reduced thiol/disulfide ratio and inhibited the kinases activities. Cysteamine administration increased the thiol/disulfide ratio and co-administration with cystine dimethyl ester prevented the inhibition of the enzymes. Regression between the thiol/disulfide ratio, and the kinases activities were significant. These results suggest that redox status may regulate energy metabolism in the rat kidney. If thiol-containing enzymes inhibition and oxidative stress occur in patients with cystinosis, it is possible that lysosomal cystine depletion may not be the only beneficial effect of cysteamine administration, but also its antioxidant and thiol-protector effect.

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.

Thiol/disulfide status regulates the activity of thiol-containing kinases related to energy homeostasis in rat kidney.

Considering that thiol-containing enzymes like kinases are critical for several metabolic pathways and energy homeostasis, we investigated the effects of cystine dimethyl ester and/or cysteamine administration on kinases crucial for energy metabolism in the kidney of Wistar rats. Animals were injected twice a day with 1.6 µmol/g body weight cystine dimethyl ester and/or 0.26 µmol/g body weight cysteamine from the 16th to the 20th postpartum day and euthanized after 12 hours. Pyruvate kinase, adenylate kinase, creatine kinase activities and thiol/disulfide ratio were determined. Cystine dimethyl ester administration reduced thiol/disulfide ratio and inhibited the kinases activities. Cysteamine administration increased the thiol/disulfide ratio and co-administration with cystine dimethyl ester prevented the inhibition of the enzymes. Regression between the thiol/disulfide ratio, and the kinases activities were significant. These results suggest that redox status may regulate energy metabolism in the rat kidney. If thiol-containing enzymes inhibition and oxidative stress occur in patients with cystinosis, it is possible that lysosomal cystine depletion may not be the only beneficial effect of cysteamine administration, but also its antioxidant and thiol-protector effect.

A Possible Anti-Inflammatory Effect of Proline in the Brain Cortex and Cerebellum of Rats.

Although many studies show the toxic effects of proline, recently it has been reported some anti-inflammatory effect of this amino acid. Our principal objective was to investigate the effects of proline on the alterations caused by LPS (lipopolysaccharide) administration in the cerebral cortex and cerebellum of young Wistar rats. The animals were divided into four groups: control (0.85% saline); proline, (12.8 µmol of proline/g body weight from day 7 to 13; 14.6 µmol of proline/g body weight from day 14 to 17 and 16.4 µmol of proline/g body weight from day 18 to 21); LPS (1 mg/g body weight); LPS plus proline. The animals were killed at 22 days of age, 12 h after the last injection, by decapitation without anesthesia. The brain cortex and cerebellum were separated for chemical determinations. The effects of proline and LPS in the cerebral cortex and cerebellum on the expression of S100B and GFAP, oxidative stress parameters, enzymes of phosphoryl transfer network activity, and mitochondrial respiration chain complexes were investigated. Two-way ANOVA showed that the administration of proline did not alter the analyzed parameter in cerebral cortex and cerebellum. On the other hand, LPS administration caused a change in these parameters. Besides, the co-administration of proline and LPS showed the ability of Pro in preventing the effects of LPS. These results indicated that LPS induces inflammation, oxidative stress, and alters energy parameters in cerebral cortex and cerebellum of the rats. Moreover, co-administration of Pro was able to prevent these harmful effects of LPS.

Hypoxanthine Induces Neuroenergetic Impairment and Cell Death in Striatum of Young Adult Wistar Rats.

Hypoxanthine is the major purine involved in the salvage pathway of purines in the brain. High levels of hypoxanthine are characteristic of Lesch-Nyhan Disease. Since hypoxanthine is a purine closely related to ATP formation, the aim of this study was to investigate the effect of intrastriatal hypoxanthine administration on neuroenergetic parameters (pyruvate kinase, succinate dehydrogenase, complex II, cytochrome c oxidase, and ATP levels) and mitochondrial function (mitochondrial mass and membrane potential) in striatum of rats. We also evaluated the effect of cell death parameters (necrosis and apoptosis). Wistar rats of 60 days of life underwent stereotactic surgery and were divided into two groups: control (infusion of saline 0.9%) and hypoxanthine (10 µM). Intrastriatal hypoxanthine administration did not alter pyruvate kinase activity, but increased succinate dehydrogenase and complex II activities and diminished cytochrome c oxidase activity and immunocontent. Hypoxanthine injection decreased the percentage of cells with mitochondrial membrane label and increased mitochondrial membrane potential labeling. There was a decrease in the number of live cells and an increase in the number of apoptotic cells by caused hypoxanthine. Our findings show that intrastriatal hypoxanthine administration altered neuroenergetic parameters, and caused mitochondrial dysfunction and cell death by apoptosis, suggesting that these processes may be associated, at least in part, with neurological symptoms found in patients with Lesch-Nyhan Disease.

Neuroprotective Effect of Creatine and Pyruvate on Enzyme Activities of Phosphoryl Transfer Network and Oxidative Stress Alterations Caused by Leucine Administration in Wistar Rats.

Maple syrup urine disease is an autosomal metabolic disease caused by a deficiency of branched-chain α-keto acid dehydrogenase complex activity. In this disease occur the accumulation of the branched-chain amino acids leucine, isoleucine, and valine and their corresponding branched-chain α-keto acids in the tissues and body fluids. The affected patients may present psychomotor development delay and mental retardation. The pathophysiology of maple syrup urine disease is not entirely understood, but leucine seems to be the primary neurotoxic metabolite. Creatine and pyruvate are energetics and antioxidants substances. In this study, we investigated the effects of leucine administration and co-administration of creatine plus pyruvate on several parameters of oxidative stress and phosphoryl transfer network in cerebral cortex and hippocampus of Wistar rats treated from the 8th to the 21st postpartum day. Leucine induced oxidative stress and diminished the activities of pyruvate kinase, adenylate kinase, cytosolic and mitochondrial creatine kinase. Co-administration of creatine plus pyruvate prevented the alterations provoked by leucine administration on the oxidative stress and the enzymes of phosphoryltransfer network. These results indicate that chronic administration of leucine may stimulate oxidative stress and alters the enzymes of phosphoryltransfer network in the cerebral cortex and hippocampus of the rats. It is possible that these effects may contribute, along with other mechanisms, to the neurological dysfunction found in patients affected by maple syrup urine disease. In this case, it is possible that creatine plus pyruvate supplementation could benefit to the patients.