Circulating Angiogenic and Senescent T Cells in Ageing and Frailty

Byrne, Thomas (2022) Circulating Angiogenic and Senescent T Cells in Ageing and Frailty. Doctoral thesis, SETU Waterford.

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Abstract

Ageing and frailty represent an increasing challenge for societies worldwide, with a growing emphasis on identifying their underlying pathophysiologies and prospects for intervention. Although not part of frailty based on some definitions employed, there is an important cardiovascular dimension to frailty. T lymphocyte subsets have been implicated both positively and negatively in vascular health and age-related vascular disease. There is evidence a circulating T cell subset exists (CD31+ angiogenic T cells) which may play a role in vascular maintenance and repair. On the other hand, there also exists a population of T cells that display pro-inflammatory function (CD28NULL senescent T cells). Ageing, an established cardiovascular risk factor has been linked with decreasing numbers of circulating CD31+ T cells and increases in CD28NULL T cells. Using flow cytometry, we have examined the effects of ageing and frailty on these cells and their discrete subsets. We have also isolated CD31+ and CD31- T cells from young adults, investigated their cytokine secretion profile and T cell differentiation state. Our key findings include (1) a progressive decrease in CD31+ T cells with ageing and a paradoxical increase in age-matched frail older adults, (2) increased CD28NULL T cells in frail older adults, which is particularly prominent in the CD8+ T cell pool (3) higher secretion of angiogenic and pro-inflammatory cytokines from CD31+ than CD31- T cells (4) CD31+ T cells exist across the T cell differentiation spectrum with considerable proportions present in the senescent T cell pool. Overall, our findings indicate that CD31+ T cells have more complex functional and phenotypic characteristics than previously described, and these characteristics should be considered in future studies investigating these cells in disease states. We have identified CD8+CD28NULL T cells as a frailty associated biomarker that may be used to track immune changes in intervention studies concerning frail populations.

Item Type:	Thesis (Doctoral)
Uncontrolled Keywords:	Angiogenic and Senescent T Cells, Ageing
Departments or Groups:	*NONE OF THESE*
Divisions:	School of Science > Department of Chemical and Life Sciences
Depositing User:	Derek Langford
Date Deposited:	27 Oct 2022 09:28
Last Modified:	27 Oct 2022 09:28
URI:	https://repository.wit.ie/id/eprint/3548

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