The Impact of Diet on Immunosenescence

Clements, Sarah Jayne (2017) The Impact of Diet on Immunosenescence. Doctoral thesis, University of East Anglia.

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Introduction: The population is ageing but this accompanies increased susceptibility to infection and age-associated diseases, as well as reduced vaccination responses; potentially attributable to reduced immune function. Immunosenescence describes the deleterious effects of ageing on the immune system and is associated with a chronic, low-grade, inflammatory state; inflammaging. Habitants of Mediterranean regions maintain good health into old age; often attributed to Mediterranean (MED)-diets.
Hypothesis: Adoption of a MED-diet by elderly subjects, in Norfolk, may improve immune responses of these individuals; particularly in terms of dendritic cell (DC) function and antibody diversity.
Experimental approach: Elderly subjects recruited onto the Nu-AGE study were randomised to the control or MED-diet groups, for one year. Blood samples were compared from pre- and post-intervention, and to blood samples from young subjects. Study compliance was assessed using high performance liquid chromatography-with tandem mass spectrometry (HPLC-MS/MS) analysis of urine samples. Immune cell subset numbers and concentrations of secreted proteins were determined by flow cytometry, after staining for surface markers and intracellular proteins. Age and dietary impact on antibody diversity was quantitated using a novel-polymerase chain reaction (PCR)-based technique developed by the Babraham Institute.
Results: The MED-diet group had higher urinary hydroxytyrosol sulphate post-intervention but self-reported diet diary analyses showed no difference in MED-diet scores. Reduced myeloid DC numbers were observed in blood samples from elderly subjects compared to young. The elevated secretion of the adipokine, resistin, after ex vivo stimulation of peripheral blood mononuclear cells (PBMCs) from elderly subjects, was significantly reduced after MED-diet intervention, but this change from baseline was not significantly different to the control group. Antibody diversity was reduced with age, dietary intervention may prevent further reductions in unique clonotypes.
Conclusions: Further evidence of numerical and functional effects of ageing on DCs, are shown. The MED-diet showed potential to impact on the ageing immune cells investigated and could provide an economical approach to address problems associated with our ageing population.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Medicine and Health Sciences > Norwich Medical School
Depositing User: Nicola Veasy
Date Deposited: 23 Mar 2018 14:41
Last Modified: 23 Mar 2018 15:14


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