Love, DRoy, NLaing, WEdmunds, Shelley2011-03-172010http://hdl.handle.net/2292/6623Nutrigenomics is the study of interactions between diet and human genotype with the aim of understanding how food components influence gene and protein expression, and of linking this interaction to differences in individual metabolism. Inflammatory Bowel Disease (IBD) is a chronic inflammatory disorder of the gastrointestinal tract involving inappropriate immune response to commensal microorganisms in a genetically susceptible host. The principal aim of the research described here was concerned with determining if aqueous and ethyl acetate extracts of gold kiwifruit (Actinidia chinensis) or green kiwifruit (Actinidia deliciosa) had immune modulating effects against inflammatory processes known to be increased in patients with IBD. This aim involved the use of in vitro and in vivo models of IBD that were studied at the molecular level. The first part of the research examined the anti-inflammatory properties of four kiwifruit extracts (KFEs) in in vitro IBD models. These models comprised primary macrophages and intestinal epithelial cells isolated from C57BL/5J or interleukin 10 gene deficient (Il10-/-) mice and RAW 264.7, a transformed murine macrophage-like cell line. All four KFEs reduced the production of the pro-inflammatory biomarker nitric oxide and of both pro- and anti-inflammatory cytokines after cells were stimulated with lipopolysaccharide. Ethyl acetate extracts exhibited greater inhibitory activity compared to aqueous extracts for each type of kiwifruit. In the second part of the research, KFEs were used as a dietary intervention in Il10-/- mice, which are an in vivo model of IBD. While all Il10-/- mice developed significant colonic inflammation compared to the C57BL/6J background strain, this was not affected by the inclusion of KFE in the diet. Whole genome gene and protein expression level profiling indicated that KFEs influenced immune signalling pathways and metabolic processes within the colonic tissue; however, the effects were subtle. These findings highlight the importance of investigating food components identified by cell-based screening assays with appropriate animal models and human clinical studies to confirm and understand their activity. While KFE anti-inflammatory activity was not confirmed in our IBD mouse model, the molecular effects identified may represent immune modulating effects that are beneficial to other inflammatory disorders.Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated.https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htmThesisCopyright: The authorQ112200759