Effect of RYGB on Oxidative Stress in Adults: a 6-Year Follow-up Study.

BACKGROUND: Roux-en-Y gastric bypass (RYGB) is effective for weight loss but may have long-term effects on markers of oxidative stress (OS). The objective of this study is to evaluate the effect of bariatric surgery with RYGB on OS blood markers in a 72-month period after surgery. METHODS: A prospective cohort study was conducted with 20 patients before and after RYGB (months M0, M6, M12, M24, and M72) compared with a control group of 35 adults assessed only once. RESULTS: The body mass index (BMI) (45.71 ± 6.97 kg/m2) decreased by 38% from M0 to M24 (17.51 ± 5.50 kg/m2, p < 0.001), followed by a 12% increase from M24 to M72 (p < 0.001). Serum concentrations of vitamin E (adjusted for total cholesterol and triglycerides) and vitamin C increased throughout the study (p < 0.001). ß-carotene levels decreased progressively through to M72 (p = 0.008). Reduced glutathione (GSH) content and catalase (CAT) activity decreased at M6, M12, and M24, but no differences were found at M72 compared with M0. Concentrations of thiobarbituric acid reactive substances (TBARS) were lower M12 and M24 in comparison with baseline values (p < 0.001 and p = 0.004, respectively) but were similar to baseline values at 72 months (p = 0.114). CONCLUSIONS: GSH content, TBARS concentrations, and CAT activity returned to baseline values 72 months after RYGB, indicating the persistence of systemic OS, possibly attributable to weight regain and/or changes in the antioxidant defenses, such as the reduction in ß-carotene levels.

Caracterização da esteatose hepática não alcoólica induzida por dieta hipoprotéica em ratos / Characterization of nonalcoholic fatty liver disease in rats for low protein diet induced

Modelo de estudo: Estudo experimental. Objetivos: este estudo teve como objetivo avaliar e caracterizar a dieta hipoprotéica como um modelo experimental para estudo de EHNA. Métodos: foram utilizados ratos da linhagem Wistar divididos em dois grupos com dietas isocalóricas: controle (GC) no qual a dieta utilizada seguiu o preconizado pela AIN-93 e hipoprotéico (GH) com quantidade de proteína reduzida de 20% para 10%. As dietas e água foram ofertadas ad libitum por quatro semanas. Após esse período, os animais foram sacrificados e analisados: glicemia; nitrogênio urinário; proteína sérica; gordura hepática; colesterol; variação de peso e quantidade de ração consumida. Resultados: glicemia e nitrogênio urinário não apresentaram diferenças significativas entre GC e GH (p>0,05), a variação de peso no último dia do experimento foi significativa (p<0,02). A porcentagem de gordura hepática foi estatisticamente maior no GH, quando comparado ao GC (p<0,04). Foram menores o nível de colesterol (p<0,01) e proteína sérica (p<0,005) no GH. A quantidade de dieta consumida não foi diferente entre os grupos, considerando-se as médias de ingestão semanal. Conclusões: neste trabalho a dieta hipoprotéica constitui um modelo de indução de EHNA que pode ser caracterizada pela diminuição da proteína sérica e do colesterol plasmático e aumento da gordura hepática, entretanto não ocorreram alterações na glicemia sugerindo que não existiu mudança na sensibilidade à insulina, constituindo assim um modelo falho para estudar um dos principais fatores de risco para o estabelecimento da EHNA, a resistência à insulina.

Model of study: Experimental study. Objectives: this study had as objective evaluate and characterize a low protein diet as an experimental model for non alcoholic fatty liver disease(NAFLD). Methods: male Wistar rats were divided in two groups with isocaloric diets: control (GC) in which the used diet followed praised for the AIN-93 and the low protein (GH), with reduced amount of protein of 20% for 10%. The diets and water had been offered ad libitum over four weeks. After this period the animals were sacrificed and analyzed: glycemia; urinary nitrogen; serum protein; liver total lipids; cholesterol; weight variation and food consumed. Results: the glycemia and the urinary nitrogen had not presented significant differences between GC and GH (p>0,05). The change of weight in the last day of the experiment was significant (p<0,02). The percentage of total liver lipids was higher in the GH, when compared with the GC (p<0,04). There was lower levels of cholesterol (p<0,01) and serum protein (0,005) in GH. The food consumed was not different between the groups. Conclusions: in this paper the low protein diet constitutes a model of NAFLD induction that can be characterized for serum protein and plasmatic cholesterol and increased fat in the liver, however not alterations in the glycemia suggest no changes in insulin sensitivity, thus constituting a defective model to study one of the main factors of risk for the establishment of the NAFLD, the resistance to insulin.

Antioxidant effect of thiamine on acutely alcoholized rats and lack of efficacy using thiamine or glucose to reduce blood alcohol content.

Although there is no consensus about the use of glucose and thiamine for the treatment of acute ethanol intoxication, this is a routine practice in many countries. Our objective was to determine the efficacy of this treatment and the changes it causes in the antioxidant status of the liver. Male Wistar rats were intoxicated with an ethanol dose of 5 g/kg and divided into three groups: ethanol (EtOH; untreated), EtOH+G (treated with glucose), and EtOH+B1 (treated with thiamine). Blood and urinary ethanol as well as hepatic malondialdehyde, reduced glutathione and vitamin E were determined in all animals. Blood alcohol levels did not differ between groups, although urinary excretion was about four times higher in the group treated with thiamine (EtOH+B1). The malondialdehyde, reduced glutathione and vitamin E values used here as parameters of the antioxidant system of the liver showed improvement for the thiamine-treated group (EtOH+B1). Treatment with glucose or thiamine was ineffective in reducing blood alcohol levels in rats with acute ethanol intoxication. However, the beneficial effect of thiamine as an antioxidant for ethanol metabolism was demonstrated. Further investigations are necessary to clarify the urinary excretion of ethanol reported here for the first time and the possibility of using thiamine as an antioxidant in situations of chronic alcohol use.

Suplementação de creatina, homocisteínae estresse oxidativo / Creatine supplementation, homocysteine and oxidative stress

A creatina é uma substância popular entre atletas devido a sua possível propriedade ergogênica. Tal popularidade incentivou autores a estudar e explorar o possível potencial terapêutico desta substância. A síntese de creatina é responsável pela maioria das transferências de grupos metila no metabolismo hepático normal. Como a homocisteína é um aminoácido formado exclusivamente a partir da desmetilação da metionina, acredita-se que a creatina e homocisteína estejam metabolicamente conectadas. Estudos têm mostrado que a hiperhomocisteinemia está diretamente ligada à formação de espécies reativas de oxigênio pela auto oxidação da homocisteína e/ou da cisteína e que tal auto-oxidação pode provocar danos celulares.O objetivo desta revisão é discutir aspectos da suplementação com creatina relacionados aos níveis de homocisteína e o estresse oxidativo.

Creatine is a popular substance among athletes due its possible ergogenic property. Such popularity has been stimulating authors to study and explore the possible potencial therapeutic effect of this substance. The synthesis of creatine is responsible for the majority methyl groups transferences in the normal hepatic metabolism. As homocysteine is an aminoacid formed exclusively from the methionine demetilation, it is believed that creatine and homocysteine are metabolically connected. Studies have show that hyperhomocysteinemia is directly linked tooxygen reactive species formation by the homocysteine and/or cysteine auto-oxidation and this can promote cellular damage. The aim of this review is to discuss some aspects of creatine supplementation on homocysteine levels and oxidative stress.