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Title: Anti-atherosclerotic effects of tomato anthocyanins : a transcriptomics approach to understanding mechanisms
Author: Achterfeldt, Sebastian
ISNI:       0000 0004 5915 7950
Awarding Body: University of East Anglia
Current Institution: University of East Anglia
Date of Award: 2015
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Background and rationale: Epidemiological data shows an inverse relationship between consumption of anthocyanins and cardiovascular disease risk, while supplementing animal diets with anthocyanin-rich food/extracts reduced atherosclerosis and altered gene expression. However, due to the presence of other bioactives, these studies cannot prove that anthocyanins cause the observed effects. To determine this, suitable control foods (i.e. similar foods lacking anthocyanins) are needed, but these do not occur naturally. Approach: An animal feeding study using genetically modified ‘purple tomatoes’, which highly express anthocyanins and equivalent anthocyanin-free red tomatoes, was undertaken which allowed direct assessment of the ability of dietary anthocyanins to affect cardiovascular disease risk. Increasing concentrations of purple tomatoes (2.5, 5 and 10 %) in purified diets containing a total of 10 % w/w tomato were used and compared to the effects of a 10 % red tomato and no tomato diet. This highly controlled intervention in the apolipoprotein E deficient mouse model assessed the dose-response of anthocyanins from tomato on atherosclerosis and gene expression. Results and conclusion: The 10 % purple tomato diet caused a 45 % mean reduction in aortic lesion size compared to the red tomato diet (p<0.001). Further, there was a clear linear dose-response (R2 = 0.999, p<0.0001 using average data) demonstrating that the anthocyanins had beneficial effects by reducing atherosclerosis in this mouse model. Gene expression data from livers and aorta of the mice showed an effect of the anthocyanin-rich tomatoes on reverse cholesterol transport, which was further supported by physiological measurements. In conclusion, it was shown for the first time that consumption of tomato anthocyanins significantly reduces atherosclerosis in the apolipoprotein E deficient mouse model via controlling reverse cholesterol transport at the level of gene expression with microRNA-33a identified as the possible molecular target.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available