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Dietary Nitrate Reshapes Gut Microbiota and Attenuates Gastric Mucosal Inflammation during Dysbiosis
238 Dietary Nitrate Reshapes Gut Microbiota and Attenuates Gastric Mucosal Inflammation during Dysbiosis Barbara S Rocha1, Mariana G Correia1, Anabela Pereira2, Gabriela Jorge da Silva1,3, Rui M Barbosa1,3, and João Laranjinha1,3 1 Center for Neuroscience and Cell Biology, Portugal, 2University of Aveiro, Portugal, 3Faculty of Pharmacy, University of Coimbra, Portugal Dietary nitrate is reduced to nitrite in the oral cavity and to NO in the stomach. In the gut, NO increases mucosal blood flow, mucus thickness and prevents microbial infections. Gut microbiota is raising a great deal of interest since it has been recognized to be crucial to maintain local and systemic welfare. Dysbiosis is associated with increased epithelial permeability and with the activation of inflammatory pathways. Here we investigate whether nitrate rescues gut physiology and microbial profile during dysbiosis. The drinking water of 4 groups of Wistar rats was supplemented with 1) antibiotic cocktail (neomycin, bacitracin, imipenem), 2) antibiotic cocktail + nitrate, 3) nitrate 4) no supplementation (water). Animals were weighted daily. after 7 days they were anesthetized and euthanized. Feces were collected before and after the treatment. Ceca were collected and weighted. The stomach was isolated and occludin, claudin-5 and ZO-1 as well as myeloperoxidase (MPO) and iNOS were analyzed (n=4). Fecal bacteria DNA was analyzed by DGGE. Antibiotic-induced weight loss was prevented by dietary nitrate suggesting a more efficient harvesting of nutrients. Also, ceca from animals with dysbiosis were larger and heavier than the ones from animals treated with nitrate under the same circumstances (p=0.0481). The expression of occludin was slightly decreased during dysbiosis, but the reactivity was recovered by nitrate (p<0.05). No differences were observed for ZO-1 or claudin-5. Nitrate prevented MPO and iNOS overexpression under dysbiosis (p<0.05). Rats treated with antibiotics and nitrate showed a microflora similar to control animals, which may suggest that gastric generation of NO recovers gut microbiota during dysbiosis. This data suggests that dietary nitrate may rescue gastric epithelial integrity and gut microbiota during dysbiosis and therefore its consumption may be recommended when antibiotics are prescribed to treat infections. doi: 10.1016/j.freeradbiomed.2014.10.271
239 Nitro-Fatty Acids Formed by Extra Virgin Olive Oil (EVOO) Consumption Modulate Mitochondrial Function in High Fat-Fed Mice Beatriz Sanchez-Calvo1, Adriana Cassina1, Eric Kelley2, Juan B. Barroso3, Homero Rubbo1, and Andrés Trostchansky1 1 Departamento de Bioquímica and Center for Free Radical and Biomedical Research, Facultad de Medicina, Uruguay, 2University of Pittsburgh, PA, USA, 3Departamento de Biología Experimental, Universidad de Jaen, Spain Extra virgin olive oil (EVOO) represents the main source of unsaturated lipids in the Mediterranean diet associated with cardioprotection and low mortality. Electrophilic lipid nitroalkenes (NO2-FA) have pleiotropic anti-inflammatory cell signaling responses in mammals. We postulate that NO2-FA could modulate mitochondrial gene expression and metabolic responses, contributing to the health benefits associated with the Mediterranean diet. Recent data showed the presence of nitrated conjugated linoleic acid (NO2-cLA) in EVOO as well as nitrolinoleic (NO2-LA) and nitro-oleic acid (NO2-OA) under gastric
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acidic nitration conditions. Herein, we evaluate if EVOO supplementation in mice under high fat diet favors NO2-FA formation, thus modulating mitochondrial function. High fat-fed mice supplemented with EVOO plus nitrite exhibited a low increase in body weight than controls, in addition to a decrease accumulation of fat in liver. Mitochondrial function was analyzed by high resolution respirometry in heart and kidney. High fat diet mice exhibited a decrease in RCR, with the EVOO plus nitrite condition improved mitochondrial function. Moreover, in the presence of EVOO plus nitrite the RCR was higher in mice under high fat diet than those without EVOO supplementation (p<0.05). When looking for respiratory chain mitochondrial activities, succinate dehydrogenase and ATPase were significantly improved in the EVOO supplementation condition. In addition, tissue lipid oxidation and carbonyls formation were lower in EVOO-supplemented animals, being greater when nitrite was present. As part of the antioxidant/anti-inflammatory actions of nitroalkenes, liver hemoxygenase-1 (HO-1) expression was increased by EVOO supplementation, concomitant with downregulation of nitric oxide synthase-2 (NOS2). Plasma proinflammatory cytokines were modulated by EVOO supplementation while NO2-FA levels increased in the EVOO/nitrite conditions, suggesting an association between NO2FA formation by EVOO and an improvement in mitochondrial function. doi: 10.1016/j.freeradbiomed.2014.10.272
240 Increased Oxidative Stress in Dyslipidemic Guinea Pigs with Fatty Liver Disease Pernille Tveden-Nyborg1, Malene M Birck1, David H Ipsen1, and Jens Lykkesfeldt1 1 University of Copenhagen, Denmark The guinea pig displays a lipoprotein profile with a high similarity to humans and may be a superior rodent model in dietary induced dyslipidemia, particularly with regards to non-alcoholic fatty liver disease (NAFLD). This study investigated the response to 16 wks high-fat diet and if a relatively subtle difference in sucrose would affect the severity of the induced changes. Guinea pigs were placed in isocaloric dietary groups (n=7) receiving either control diet (CTRL), high-fat (0.35% cholesterol, 18.5% fat and 15% sucrose) (HF) or high-fat + 20%sucrose (HFS). Bodyweights were equal between groups, however change in overall fat % (DEXA scan) was decreased and liver weights increased (P<0.01) in HF and HFS. Plasma lipoprotein profile showed increased LDL-chol in HF and HFS (P<0.05) but no difference in HDL-chol. Moreover, increased MDA, isoprostanes and oxLDL was observed in HF/HFS animals (P<0.05 or less). Liver enzymes ALT and AST were significantly increased in HF and HFS (P<0.01), histological findings confirming lipid infiltrations in the liver of HF and HFS. In liver, increased MDA, decreased vitC but increased ascorbate oxidation was observed. In conclusion, we find that diet induced dyslipidemia in guinea pigs induce oxidative stress both systemically and in the liver in agreement with the development of NAFLD in humans. doi: 10.1016/j.freeradbiomed.2014.10.273
SFRBM 2014
239 Nitro-Fatty Acids Formed by Extra Virgin Olive Oil (EVOO) Consumption Modulate Mitochondrial Function in High Fat-Fed Mice Beatriz Sanchez-Calvo1, Adriana Cassina1, Eric Kelley2, Juan B. Barroso3, Homero Rubbo1, and Andrés Trostchansky1 1 Departamento de Bioquímica and Center for Free Radical and Biomedical Research, Facultad de Medicina, Uruguay, 2University of Pittsburgh, PA, USA, 3Departamento de Biología Experimental, Universidad de Jaen, Spain Extra virgin olive oil (EVOO) represents the main source of unsaturated lipids in the Mediterranean diet associated with cardioprotection and low mortality. Electrophilic lipid nitroalkenes (NO2-FA) have pleiotropic anti-inflammatory cell signaling responses in mammals. We postulate that NO2-FA could modulate mitochondrial gene expression and metabolic responses, contributing to the health benefits associated with the Mediterranean diet. Recent data showed the presence of nitrated conjugated linoleic acid (NO2-cLA) in EVOO as well as nitrolinoleic (NO2-LA) and nitro-oleic acid (NO2-OA) under gastric
S102
acidic nitration conditions. Herein, we evaluate if EVOO supplementation in mice under high fat diet favors NO2-FA formation, thus modulating mitochondrial function. High fat-fed mice supplemented with EVOO plus nitrite exhibited a low increase in body weight than controls, in addition to a decrease accumulation of fat in liver. Mitochondrial function was analyzed by high resolution respirometry in heart and kidney. High fat diet mice exhibited a decrease in RCR, with the EVOO plus nitrite condition improved mitochondrial function. Moreover, in the presence of EVOO plus nitrite the RCR was higher in mice under high fat diet than those without EVOO supplementation (p<0.05). When looking for respiratory chain mitochondrial activities, succinate dehydrogenase and ATPase were significantly improved in the EVOO supplementation condition. In addition, tissue lipid oxidation and carbonyls formation were lower in EVOO-supplemented animals, being greater when nitrite was present. As part of the antioxidant/anti-inflammatory actions of nitroalkenes, liver hemoxygenase-1 (HO-1) expression was increased by EVOO supplementation, concomitant with downregulation of nitric oxide synthase-2 (NOS2). Plasma proinflammatory cytokines were modulated by EVOO supplementation while NO2-FA levels increased in the EVOO/nitrite conditions, suggesting an association between NO2FA formation by EVOO and an improvement in mitochondrial function. doi: 10.1016/j.freeradbiomed.2014.10.272
240 Increased Oxidative Stress in Dyslipidemic Guinea Pigs with Fatty Liver Disease Pernille Tveden-Nyborg1, Malene M Birck1, David H Ipsen1, and Jens Lykkesfeldt1 1 University of Copenhagen, Denmark The guinea pig displays a lipoprotein profile with a high similarity to humans and may be a superior rodent model in dietary induced dyslipidemia, particularly with regards to non-alcoholic fatty liver disease (NAFLD). This study investigated the response to 16 wks high-fat diet and if a relatively subtle difference in sucrose would affect the severity of the induced changes. Guinea pigs were placed in isocaloric dietary groups (n=7) receiving either control diet (CTRL), high-fat (0.35% cholesterol, 18.5% fat and 15% sucrose) (HF) or high-fat + 20%sucrose (HFS). Bodyweights were equal between groups, however change in overall fat % (DEXA scan) was decreased and liver weights increased (P<0.01) in HF and HFS. Plasma lipoprotein profile showed increased LDL-chol in HF and HFS (P<0.05) but no difference in HDL-chol. Moreover, increased MDA, isoprostanes and oxLDL was observed in HF/HFS animals (P<0.05 or less). Liver enzymes ALT and AST were significantly increased in HF and HFS (P<0.01), histological findings confirming lipid infiltrations in the liver of HF and HFS. In liver, increased MDA, decreased vitC but increased ascorbate oxidation was observed. In conclusion, we find that diet induced dyslipidemia in guinea pigs induce oxidative stress both systemically and in the liver in agreement with the development of NAFLD in humans. doi: 10.1016/j.freeradbiomed.2014.10.273
SFRBM 2014