Fernanda Aparecida Domenici

DNA oxidative damage in patients with dialysis treatment

Background/Aims. Chronic renal patients on hemodialysis (HD) and peritoneal dialysis (PD) treatment are exposed to oxidative stress and DNA damage. The objective of this study was to assess the oxidative damage to DNA in end-stage chronic renal failure, before and after vitamin E supplementation. Methods. Patients on HD (n = 29) and PD (n = 22) received oral supplementation with 300 mg vitamin E three times a week for 4 weeks. A blood sample was collected at the beginning and at the end of the supplementation cycle for the determination of vitamin E levels (high-performance liquid chromatography), carbonyl groups, and DNA damage (8-hydroxy 2′-deoxyguanosine [8-OHdG] and comet assay). Results. After supplementation, vitamin E concentration was increased by about 50%. Protein oxidation was initially observed in both groups, with a reduction after supplementation. DNA damage detected by the comet assay and by 8-OHdG analysis was significantly reduced (p< 0.05) after supplementation in both groups. Conclusions. Vitamin E supplementation reduced oxidative DNA damage in both HD and PD patients. Treatments such as HD and PD induce oxidative stress and consequent DNA damage, and increased plasma vitamin E levels significantly contribute to the normalization of these events.

Peroxisome proliferator-activated receptors alpha and gamma2 polymorphisms in nonalcoholic fatty liver disease: a study in Brazilian patients.

BACKGROUND Non-alcoholic fatty liver disease (NAFLD) refers to the accumulation of hepatic steatosis in the absence of excess alcohol consumption. The pathogenesis of fatty liver disease and steatohepatitis (NASH) is not fully elucidated, but the common association with visceral obesity, hyperlipidemia, hypertension and type 2 diabetes mellitus (T2DM) suggests that it is the hepatic manifestation of metabolic syndrome. Peroxisome proliferator-activated receptor PPARα and PPARγ are members of a family of nuclear receptors involved in the metabolism of lipids and carbohydrates, adipogenesis and sensitivity to insulin. The objective of this study was to analyze the polymorphisms Leu162Val of PPARα and Pro12Ala of PPARγ as genetic risk factors for the development and progression of NAFLD. METHODS One hundred and three NAFLD patients (89 NASH, 14 pure steatosis) and 103 healthy volunteers were included. Single nucleotide polymorphisms (SNPs) Leu162Val and Pro12Ala were analyzed by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). RESULTS NASH patients presented higher BMI, AST and prevalence of T2DM than patients with pure steatosis. A higher prevalence of 12Ala allele was observed in the NASH Subgroup when compared to Control Group. When we grouped NASH and Steatosis Subgroups (NAFLD), we found lower serum glucose and more advanced fibrosis in the Leu162Val SNP. On the other hand, there was no statistical difference in clinical, laboratorial and histological parameters according to the Pro12Ala SNP. CONCLUSIONS We documented a lower prevalence of 12Ala allele of gene PPARγ in the NASH Subgroup when compared to Control Group. In NAFLD patients, there were no associations among the occurrence of Pro12Ala SNP with clinical, laboratorial and histological parameters. We also documented more advanced fibrosis in the Leu162Val SNP. The obtained data suggest that Pro12Ala SNP may result in protection against liver injury and that Leu162Val SNP may be involved in the progression of NAFLD.

Progression of lipid peroxidation measured as thiobarbituric acid reactive substances, damage to DNA and histopathological changes in the liver of rats subjected to a methionine-choline-deficient diet.

Methionine-choline-deficient diet represents a model for the study of the pathogenesis of steatohepatitis. Male rats were divided into three groups, the first group receiving a control diet and the other two groups receiving a methionine-choline-deficient diet for 1 month (MCD1) and for 2 months (MCD2), respectively. The livers of the animals were collected for the determination of vitamin E, thiobarbituric acid reactive substances (TBARS), GSH concentration, DNA damages, and for histopathological evaluation. The hepatic TBARS and GSH content was higher (P < 0.05) in the groups receiving the experimental diet (MCD1 and MCD2) compared to control diet, and hepatic vitamin E concentration differed (P < 0.05) between the MCD1 and MCD2 groups, with the MCD2 group presenting a lower concentration. Damage to hepatocyte DNA was greater (P < 0.05) in the MCD2 group (262.80 DNA injuries/100 hepatocytes) compared to MCD1 (136.4 DNA injuries/100 hepatocytes) and control diet (115.83 DNA injuries/100 hepatocytes). Liver histopathological evaluation showed that steatosis, present in experimental groups was micro- and macro-vesicular and concentrated around the centrolobular vein, zone 3, with preservation of the portal space. The inflammatory infiltrate was predominantly periductal and the steatosis and inflammatory infiltrate was similar in the MCD1 and MCD2 groups, although the presence of Mallory bodies was greater in the MCD2 group. The study describes the contribution of a methionine-choline-deficient diet to the progression of steatosis, lipid peroxidation and hepatic DNA damage in rats, serving as a point of reflection about the role of these nutrients in the western diet and the elevated non-alcoholic steatohepatitis rates in humans.

Copper-Zinc ratio and nutritional status in colorectal cancer patients during the perioperative period

PURPOSE This study aimed to determine Cu/Zn ratio, nutritional and inflammatory status in patients during the perioperative period for colorectal cancer. METHODS The study included patients with histological diagnosis of colorectal adenocarcinoma (Cancer Group, n=46) and healthy volunteers (Control Group, n=28). We determined habitual food intake, body composition, laboratory data of nutritional status, serum calprotectin and plasma Cu and Zn concentrations. Mann-Whitney U-test was performed between-group comparisons and Spearman correlation test for correlations between the variables. RESULTS Individuals in the Cancer Group presented significantly lower BMI, fat mass, plasma hemoglobin, total protein and albumin as compared with the Control Group. Serum calprotectin[70.1 ng/mL (CI95% 55.8-84.5) vs.53.3 ng/mL (40.3-66.4), p=0.05], plasma Cu concentrations [120 µg/dL(CI95% 114-126) vs. 106 µg/dL(CI95% 98-114), p<0.01] and the Cu/Zn ratio [1.59 (CI95% 1.48-1.71)vs. 1.35 (CI95% 1.23-1.46), p=0.01]were higher in patients with colorectal cancer than in controls. Additionally, the Cancer Group showed negative correlations between the Cu/Zn ratio and Zn intake, hemoglobin, serum albumin, and positive correlation between the Cu/Zn ratio and serum calprotectin. CONCLUSION These results indicate that an increased plasma Cu/Zn ratio and serum calprotectin, and decreased protein values may be a result of the systemic inflammatory response to the tumor process.

Effect of methionine load on homocysteine levels, lipid peroxidation and DNA damage in rats receiving ethanol

Changes in the metabolism of methionine can cause hyperhomocysteinemia, inducing a triad of atherosclerosis, hypertension, and increased oxidative stress. The generation of free radicals and oxidative damage to DNA is important in the liver damage caused by ethanol. In this study, the effect of methionine overload associated or otherwise with acute administration of ethanol on homocysteine values, damage to DNA, lipoperoxidation and vitamin E was evaluated. Thirty rats were divided into 3 groups: Group Ethanol 24 hours (EG24), Group Methionine 24 hours (MG24), and Group Methionine and Ethanol 24 hours (MEG24). TBARS, vitamin E, GS and, homocysteine values were determined and the Comet assay was carried out. Increased GSH, vitamin E and homocysteine levels were observed for MEG24, and increased TBARS were observed in EG24. The Comet assay showed an increase in DNA damage in EG24 and DNA protection in MEG24. The administration of ethanol decreased antioxidant levels and increased TBARS, indicating the occurrence of oxidative stress with possible DNA damage. The combination of methionine and ethanol had a protective effect against the ethanol-induced damage, but increased the levels of homocysteine.

Betaine; a potential agent for the treatment of hepatopathy associated with short bowel syndrome

BACKGROUND The hepatopathy associated with short bowel syndrome (SBS) is a multifactorial disease associated with poor prognosis. Besides intestinal transplantation, no other treatment has been shown effective. The current study evaluated the efficacy of betaine for the treatment of hepatopathy associated with SBS. METHODS A prospective, unicentric, non-placebo controlled trial was carried out. After initial evaluation, 10g of betaine anhydrous was administrated to SBS patients in two divided doses for three months. The hepatic steatosis was assessed through nuclear magnetic resonance (NMR), the inflammatory response by interleukin- 6 (IL-6), tumor necrosis factor-α(TNF-α) and ferritin, besides the hepatic lesion through hepatic enzymes and bilirubin. Furthermore, the effect of betaine on homocysteine was evaluated as well as its safety and tolerability in this group of patients. RESULTS After three months supplementation, patients showed decreased percentage of hepatic fat (p = 0.03) through triphasic NMR examination. There was no significant reduction of serum levels for inflammatory proteins and hepatic lesion markers. Homocysteinemia also did not present significant decrease. The most prevalent side effects were diarrhea and nausea, reported in 62% of the participants; however, these symptoms were transient and not severe enough to justify the treatment interruption. Parenteral nutrition-dependent patients did not present different hepatic lesion degree compared to patients who do not need the prolonged use of it. CONCLUSIONS Betaine was shown to be a potential agent for the treatment of hepatopathy associated with SBS, which was evidenced by NMR, although the markers for hepatic lesion have not presented significant decrease.

INFLUENCE OF OXIDATIVE STRESS AND OBESITY IN PATIENTS WITH NONALCOHOLIC STEATOHEPATITIS

BACKGROUND Nonalcoholic steatohepatitis is considered the hepatic manifestation of metabolic syndrome and it is particularly associated to the insulin resistance, hypertension, obesity and abnormalities in lipid and glucose metabolism. OBJECTIVE Considering the importance of obesity and oxidative stress in the pathophysiology of nonalcoholic steatohepatitis, this study aimed to evaluate the presence and association of the obesity and oxidative stress in this pathology. METHODS Fifteen outpatients with nonalcoholic steatohepatitis (nonalcoholic steatohepatitis group), diagnosed according to the histopathological findings from the liver biopsy, and 15 body mass index-matched subjects (non nonalcoholic steatohepatitis group) without nonalcoholic steatohepatitis were included. All volunteers were registered in a Brazilian University Hospital. Nutritional assessment (weight, height, body mass index and waist circumference) and biochemical analysis (fasting glucose, liver enzymes, lipid profile, leptin, superoxide dismutase, glutathione peroxidase, vitamins C and E, catalase and 8-isoprostane) were performed for all the participants. The student t test was used for statistical analysis, with P<0.05 as the significant factor. RESULTS Nonalcoholic steatohepatitis patients had higher fasting glucose, hepatic enzymes (serum aspartate aminotransaminase, alanine aminotransaminase, gamma glutamyl transferase, alkaline phosphatase), triglycerides and superoxide dismutase and lower glutathione peroxidase values than non nonalcoholic steatohepatitis individuals. CONCLUSION This paper demonstrates that only the presence of obesity is not enough to trigger alterations in all the studied biomarkers. Despite the majority of oxidative stress markers being found to be similar in both conditions, the nonalcoholic steatohepatitis subjects could be slightly more affected than the non nonalcoholic steatohepatitis individuals.

Vitamin E and tannic acid improve DNA damage in rats submitted chronic ethanol administration

Purpose – Chronic ethanol consumption induces lipid peroxidation by increasing free radicals or reducing antioxidants and may increase damage to hepatic DNA. Tannins are polyphenolic metabolites present in various plants and one of their effects is antioxidant activity that reduces lipoperoxidation, as is the case for vitamin E. This paper aims to assess the role of tannic acid and vitamin E in lipid peroxidation and in DNA damage in rats receiving ethanol.Design/methodology/approach – A total of 60 Wistar rats were divided into six groups: control+ethanol (0‐24hs), tannic acid+ethanol (0‐24 hs), and vitamin E+ethanol (0‐24 hs). The animals were sacrificed immediately (0 hour) or 24 hours after a period of four weeks of ethanol administration and the following measurements were made: plasma vitamin E and liver glutathione, thiobarbituric acid resistant substances, and α‐tocopherol. The comet test was also applied to hepatocytes.Findings – Ethanol administration led to an increase in DNA damage (148.67±15....