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Novel therapies for NAFLD

dc.contributor.authorNivala, Angela Marie, author
dc.contributor.authorPagliassotti, Michael, advisor
dc.contributor.authorVivanco, Jorge, committee member
dc.contributor.authorFrye, Melinda, committee member
dc.contributor.authorVanamala, Jairam, committee member
dc.date.accessioned2007-01-03T05:43:15Z
dc.date.available2007-01-03T05:43:15Z
dc.date.issued2011
dc.description.abstractBackground/Aims Non Alcoholic Fatty Liver Disease (NAFLD) is a chronic liver disease often associated with metabolic disorders like type 2 diabetes, cardiovascular disease, obesity, and metabolic syndrome. It is characterized by hepatic fat accumulation (steatosis) that is at or above 5% of liver weight in the absence of excessive alcohol consumption (< 20 g/day). Current treatment for NAFLD focuses on reducing body weight and improving insulin action. The intent of this thesis was to identify therapies that targeted the liver. In the first aim, we examined whether secretions from plant roots contained compounds that restricted lipid accumulation or improved insulin action. The second aim examined whether taurine could prevent characteristic features of disease progression. Specifically, we hypothesized that (1) onion root exudates will prevent or reduce lipid accumulation and improve insulin signaling and (2) taurine will prevent or reduce endoplasmic reticulum (ER) stress, oxidative stress and liver injury. Methods To examine these hypotheses, liver cells and dietary models of NAFLD were employed. Analyses focused on hepatic triglycerides, insulin signaling, ER stress, oxidative stress and inflammation using basic biochemical methods such as western blotting, Real Time PCR, immunohistochemistry and enzyme-linked assays. Results Onion root exudates prevented fatty acid-mediated lipid accumulation and enhanced insulin signaling in H4IIE liver cells. Onion root exudates reduced plasma glucose, free fatty acids (FFA), and improved insulin action in rats fed a high fat diet. Taurine mitigated palmitate-mediated caspase-3 activity, cell death, ER stress, and oxidative stress in H4IIE liver cells and primary hepatocytes. In rats fed a high sucrose diet, taurine supplementation significantly reduced hepatic lipid accumulation, liver injury, inflammation, plasma triglycerides and insulin levels. The high sucrose diet resulted in an induction of multiple components of the unfolded protein response (UPR) in the liver consistent with ER stress which was ameliorated by taurine supplementation. Treatment of mice with the ER stress inducing agent tunicamycin resulted in liver injury, UPR induction and hepatic lipid accumulation, and this was significantly ameliorated by supplementation with taurine. Conclusion Both onion root exudates and taurine reduced metabolic abnormalities associated with NAFLD. Onion root exudates appear to exert this effect through reduced lipid accumulation and enhanced insulin sensitivity in the liver, while taurine reduced hepatic steatosis, ER stress, oxidative stress and liver injury. Overall, onion root exudates and taurine show promise as novel therapies for the treatment of NAFLD.
dc.format.mediumborn digital
dc.format.mediumdoctoral dissertations
dc.identifierNivala_colostate_0053A_10304.pdf
dc.identifier.urihttp://hdl.handle.net/10217/49853
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado State University. Libraries
dc.relation.ispartof2000-2019
dc.rightsCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.
dc.subjecthepatic steatosis
dc.subjectinsulin resistance
dc.subjectlipotoxicity
dc.subjectNAFLD
dc.subjectroot exudates
dc.subjecttaurine
dc.titleNovel therapies for NAFLD
dc.typeText
dcterms.rights.dplaThis Item is protected by copyright and/or related rights (https://rightsstatements.org/vocab/InC/1.0/). You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
thesis.degree.disciplineFood Science and Human Nutrition
thesis.degree.grantorColorado State University
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy (Ph.D.)

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