Fernanda Barbisan

Quercetin protects the impairment of memory and anxiogenic-like behavior in rats exposed to cadmium: Possible involvement of the acetylcholinesterase and Na+,K+-ATPase activities

The present study investigated the effects of quercetin in the impairment of memory and anxiogenic-like behavior induced by cadmium (Cd) exposure. We also investigated possible alterations in acetylcholinesterase (AChE), Na(+),K(+)-ATPase and δ-aminolevulinate dehydratase (δ-ALA-D) activities as well as in oxidative stress parameters in the CNS. Rats were exposed to Cd (2.5mg/kg) and quercetin (5, 25 or 50mg/kg) by gavage for 45days. Animals were divided into eight groups (n=10-14): saline/control, saline/Querc 5mg/kg, saline/Querc 25mg/kg, saline/Querc 50mg/kg, Cd/ethanol, Cd/Querc 5mg/kg, Cd/Querc 25mg/kg and Cd/Querc 50mg/kg. Results demonstrated that Cd impaired memory has an anxiogenic effect. Quercetin prevented these harmful effects induced by Cd. AChE activity decreased in the cerebral cortex and hippocampus and increased in the hypothalamus of Cd-exposed rats. The Na(+),K(+)-ATPase activity decreased in the cerebral cortex, hippocampus and hypothalamus of Cd-exposed rats. Quercetin prevented these effects in AChE and Na(+),K(+)-ATPase activities. Reactive oxygen species production, thiobarbituric acid reactive substance levels, protein carbonyl content and double-stranded DNA fractions increased in the cerebral cortex, hippocampus and hypothalamus of Cd-exposed rats. Quercetin totally or partially prevents these effects caused by Cd. Total thiols (T-SHs), reduced glutathione (GSH), and reductase glutathione (GR) activities decreased and glutathione S-transferase (GST) activity increased in Cd exposed rats. Co-treatment with quercetin prevented reduction in T-SH, GSH, and GR activities and the rise of GST activity. The present findings show that quercetin prevents alterations in oxidative stress parameters as well as AChE and Na(+),K(+)-ATPase activities, consequently preventing memory impairment and anxiogenic-like behavior displayed by Cd exposure. These results may contribute to a better understanding of the neuroprotective role of quercetin, emphasizing the influence of this flavonoid in the diet for human health, possibly preventing brain injury associated with Cd intoxication.

The protective effects of guaraná extract (Paullinia cupana) on fibroblast NIH-3T3 cells exposed to sodium nitroprusside.

The antioxidant effects of the hydro-alcoholic guaraná extract (Paullinia cupana var. sorbilis Mart.) on nitric oxide (NO) and other compounds generated from the degradation of sodium nitroprusside (SNP) in an embryonic fibroblast culture (NIH-3T3 cells) were evaluated. The guaraná bioactive compounds were initially determined by high-performance liquid chromatography: caffeine=12.240 mg/g, theobromine=6.733 mg/g and total catechins=4.336 mg/g. Cells were exposed to 10 μM SNP during a 6 h period because the cells exhibited >90% mortality at this concentration. Guaraná was added to the cultures in five concentrations (0.5, 1, 5, 10 and 20 mg/mL). The guaraná antioxidant effect was evaluated by viability assays, biochemical oxidation [lipid peroxidation, catalase and superoxide dismutase (SOD) activity] and genotoxicity (DNA Comet assay) analysis. Additionally, oxidative stress was evaluated by a 2,7-dihydrodichlorofluorescein diacetate fluorescence assay. Guaraná reverted the SNP toxicity mainly at lower concentrations (<5 mg), which decreased cell mortality, lipid peroxidation, DNA damage and cell oxidative stress as well as increased the SOD levels. These results demonstrate that guaraná has an antioxidant effect on NO metabolism in situations with higher cellular NO levels.

Methotrexate-Related Response on Human Peripheral Blood Mononuclear Cells May Be Modulated by the Ala16Val-SOD2 Gene Polymorphism

Methotrexate (MTX) is a folic acid antagonist used in high doses as an anti-cancer treatment and in low doses for the treatment of some autoimmune diseases. MTX use has been linked to oxidative imbalance, which may cause multi-organ toxicities that can be attenuated by antioxidant supplementation. Despite the oxidative effect of MTX, the influence of antioxidant gene polymorphisms on MTX toxicity is not well studied. Therefore, we analyzed here whether a genetic imbalance of the manganese-dependent superoxide dismutase (SOD2) gene could have some impact on the MTX cytotoxic response. An in vitro study using human peripheral blood mononuclear cells (PBMCs) obtained from carriers with different Ala16Val-SOD2 genotypes (AA, VV and AV) was carried out, and the effect on cell viability and proliferation was analyzed, as well as the effect on oxidative, inflammatory and apoptotic markers. AA-PBMCs that present higher SOD2 efficiencies were more resistance to high MTX doses (10 and 100 µM) than were the VV and AV genotypes. Both lipoperoxidation and ROS levels increased significantly in PBMCs exposed to MTX independent of Ala16Val-SOD2 genotypes, whereas increased protein carbonylation was observed only in PBMCs from V allele carriers. The AA-PBMCs exposed to MTX showed decreasing SOD2 activity, but a concomitant up regulation of the SOD2 gene was observed. A significant increase in glutathione peroxidase (GPX) levels was observed in all PBMCs exposed to MTX. However, this effect was more intense in AA-PBMCs. Caspase-8 and -3 levels were increased in cells exposed to MTX, but the modulation of these genes, as well as that of the Bax and Bcl-2 genes involved in the apoptosis pathway, presented a modulation that was dependent on the SOD2 genotype. MTX at a concentration of 10 µM also increased inflammatory cytokines (IL-1β, IL-6, TNFα and Igγ) and decreased the level of IL-10 anti-inflammatory cytokine, independent of SOD2 genetic background. The results suggest that potential pharmacogenetic effect on the cytotoxic response to MTX due differential redox status of cells carriers different SOD2 genotypes.

Functional, balance and health determinants of falls in a free living community Amazon riparian elderly

The aim of this study was to investigate socio-economic, clinical, anthropometric, balance and functional fitness factors present in Amazon riparian older persons that can be associated with a risk of falling. A cross sectional study was performed with 637 riverine elderly residents (≥60 years old) in Maués city Amazonas, Brazil. The elderly were grouped in two categories with and without a history of falls in the past six months. The following variables were compared between these groups: self-reported social and health conditions; biochemical and physiological variables related to the control of metabolic diseases; body composition; hand grip strength; functional fitness evaluation using the Senior Fitness Test (SFT) battery, and balance condition using the Berg Balance Test (BBT). The prevalence of at least one fall in the past six months was 24.6% (n=157) and was similar between the sexes. The mean age between males and females with and without a history of falls was also similar (males with falls=72.67 ± 8.86; males with no falls=73.26 ± 7.58) female falls=71.78 ± 8.18, female with no falls=71.48 ± 8.17). A history of falls was associated with hospitalization in the last year and to self-health perception to both sexes and presence of chronic morbidity and percentage of body fat (BF) to women. However, the other variables including balance and functional fitness, did not present differences between elderly with and without a history of falls. These results suggest that falls experienced by the riparian elderly are strongly associated to accidents due to environmental conditions related to daily life.

Superoxide-hydrogen peroxide imbalance interferes with colorectal cancer cells viability, proliferation and oxaliplatin response

The role of superoxide dismutase manganese dependent enzyme (SOD2) in colorectal cancer is presently insufficiently understood. Some studies suggest that high SOD2 levels found in cancer tissues are associated with cancer progression. However, thus far, the role of colorectal cancer superoxide-hydrogen peroxide imbalance has not yet been studied. Thus, in order to address this gap in extant literature, we performed an in vitro analysis using HT-29 colorectal cell line exposed to paraquat, which generates high superoxide levels, and porphyrin, a SOD2 mimic molecule. The effect of these drugs on colorectal cancer cell response to oxaliplatin was evaluated. At 0.1 μM concentration, both drugs exhibited cytotoxic and antiproliferative effect on colorectal cancer cells. However, this effect was more pronounced in cells exposed to paraquat. Paraquat also augmented the oxaliplatin cytotoxic and antiproliferative effects by increasing the number of apoptosis events, thus causing the cell cycle arrest in the S and M/G2 phases. The treatments were also able to differentially modulate genes related to apoptosis, cell proliferation and antioxidant enzyme system. However, the effects were highly variable and the results obtained were inconclusive. Nonetheless, our findings support the hypothesis that imbalance caused by increased hydrogen peroxide levels could be beneficial to cancer cell biology. Therefore, the use of therapeutic strategies to decrease hydrogen peroxide levels mainly during oxaliplatin chemotherapy could be clinically important to the outcomes of colorectal cancer treatment.

Haloperidol and Risperidone at high concentrations activate an in vitro inflammatory response of RAW 264.7 macrophage cells by induction of apoptosis and modification of cytokine levels

Antipsychotic drugs, such as haloperidol and risperidone, are used in long-term treatment of psychiatric patients and thus increase the risk of obesity and other metabolic dysfunctions. Available evidence suggests that these drugs have pro-inflammatory effect, which contributes to the establishment of endocrine disturbances. However, results yielded by extant studies are inconsistent. Therefore, in this work, we tested the in vitro effects of different high concentrations of haloperidol and risperidone on the activation of isolated macrophages (RAW 264.7 cell line). The results indicated that macrophages were activated by both drugs. In addition, the activation involved an increase in nitric oxide levels and apoptosis events by modulation of caspases 8 and 3 levels and a decrease of the Bcl-2/BAX gene expression ratio. Cells treated with haloperidol and risperidone also presented higher concentrations of inflammatory cytokines (IL-1β, IL-6, TNFα) and low levels of IL-6 anti-inflammatory cytokine in a dose-dependent manner. Despite the limitation of cell line studies based solely on macrophages cells, we suggest that antipsychotic drugs could potentially exacerbate inflammatory processes in peripheral tissues (blood and fat). The continued activation of macrophages could contribute to the development of obesity and other endocrine disturbances caused by the use of antipsychotic drugs.

The effects of rosuvastatin on lipid-lowering, inflammatory, antioxidant and fibrinolytics blood biomarkers are influenced by Val16Ala superoxide dismutase manganese-dependent gene polymorphism

Rosuvastatin is a cholesterol-lowering drug that also attenuates the inflammatory process and oxidative stress via the reduction of superoxide anion production. Superoxide anions are metabolized by manganese-dependent superoxide dismutase (MnSOD or SOD2) in the mitochondria. In humans, there is a gene polymorphism where a change of alanine (Ala) to valine (Val) occurs at the 16th amino acid (Ala16Val-SOD2). The VV genotype has been associated with the risk of developing several metabolic diseases, such as hypercholesterolemia. Thus, to further explore this phenomenon, this study investigated the influence of the Val16Ala-SOD2 polymorphism on the lipid profile and inflammatory and fibrinolytic biomarkers of 122 hypercholesterolemic patients undergoing the first pharmacological cholesterol-lowering therapy who were treated with 20 mg rosuvastatin for 120 days. The findings indicate that the VV patients who present a low-efficiency SOD2 enzyme exhibit an attenuated response to rosuvastatin compared with the A-allele patients. The effect of rosuvastatin on inflammatory and fibrinolytic biomarkers was also less intense in the VV patients. These results suggest some pharmacogenetic effects of Val16Ala-SOD2 in hypercholesterolemia treatment.

Genoprotective and hepatoprotective effects of Guarana (Paullinia cupana Mart. var. sorbilis) on CCl4-induced liver damage in rats

Abstract Context: Several biological effects of Paullinia cupana (guarana) have been demonstrated, but little information is available on its effects on the liver. Objective: The current study was designed to evaluate the hepatoprotective and genoprotective effects of powder seeds from guarana on CCl4-induced liver injury in rats. Materials and methods: Male Wistar rats were pretreated with guarana powder (100, 300 and 600 mg/kg) or silymarin 100 mg/kg daily for 14 days before treatment with a single dose of CCl4 (50% CCl4, 1 mL/kg, intraperitoneally). Results: The treatment with CCl4 significantly increased the serum activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). In addition, CCl4 increased the DNA damage index in hepatocytes. Guarana in all concentrations was effective in decreasing the ALT and AST activities when compared with the CCl4-treated group. The treatment with guarana decreased DNA damage index when compared with the CCl4-treated group. In addition, the DNA damage index showed a significant positive correlation with AST and ALT. Discussion and conclusion: These results indicate that the guarana has hepatoprotective activity and prevents the DNA strand breakage in the CCl4-induced liver damage in rats.

Guaraná a Caffeine-Rich Food Increases Oxaliplatin Sensitivity of Colorectal HT-29 Cells by Apoptosis Pathway Modulation

We investigated the in vitro effects of guaraná and its main metabolites (caffeine, theobromine and catechin) on cytotoxicity and cell proliferation on colorectal cancer (CRC) line HT-29 cells and on oxaliplatin sensitivity. The cells were exposed to different concentrations of guaraná extract with and without oxaliplatin. The concentrations of bioactive molecules were also estimated considering their potential proportion on guaraná hydro-alcoholic extract. Apoptosis effect was analyzed by annexin V quantification using flow cytometry, while apoptosis pathway gene modulation (p53, Bax/Bcl-2 genes ratio, caspases 8 and 3) was determined by qRT-PCR analysis. Cells exposed to guaraná at a concentration of 100 μg/mL presented a similar cytotoxic effect as HT-29 cells treated with oxaliplatin and did not affect the sensitivity of the drug. Guaraná presented cell anti-proliferative effect and increased anti-proliferative oxaliplatin sensitivity at all concentrations tested here. Guaraná was able to induce apoptosis and up-regulate the p53 and Bax/Bcl-2 genes.

In Vitro Oxidation of Collagen Promotes the Formation of Advanced Oxidation Protein Products and the Activation of Human Neutrophils

The accumulation of advanced oxidation protein products (AOPPs) has been linked to several pathological conditions. Here, we investigated collagen as a potential source for AOPP formation and determined the effects of hypochlorous acid (HOCl)-treated collagen (collagen-AOPPs) on human neutrophil activity. We also assessed whether alpha-tocopherol could counteract these effects. Exposure to HOCl increased the levels of collagen-AOPPs. Collagen-AOPPs also stimulated the production of AOPPs, nitric oxide (NO), superoxide radicals (O2−), and HOCl by neutrophils. Collagen-AOPPs induced apoptosis and decreased the number of viable cells. Alpha-tocopherol prevented the formation of collagen-AOPPs, strongly inhibited the collagen-AOPP-induced production of O2− and HOCl, and increased the viability of neutrophils. Our results suggest that collagen is an important protein that interacts with HOCl to form AOPPs, and consequently, collagen-AOPP formation is related to human neutrophil activation and cell death.