The effects of age and fitness status on circulating angiogenic T-cells

Stephen, Luke Richard Adam

Abstract

Advancing age is associated with a decline in immune cell function, both immunological function and potential for immune cells to participate in tissue repair. Discrete subsets of T-cells, such as CD31+ T cells, also known as angiogenic T cells (TANG), have strong angiogenic properties; however, the number of these cells in older populations is reportedly decreased. Evidence shows that T-cells are heavily influenced by cardiorespiratory fitness (CRF) and physical activity levels. However, the relationship between CRF and the ageing tissue regenerative T-cell subsets has yet to be explored. For the first time, this thesis investigates the effect of advancing age on specific T-cell subsets involved in vascular tissue repair, and the effects of CRF. Within this study, the link between these cells, age and cardiorespiratory fitness has been explored. The data demonstrate that CD31+ T-cells (TANG) contain more VEGF-A protein, indicative of greater angiogenic capability, than CD31- Tcells (13097 ± 10942 AU vs 12424 ± 11156 AU respectively, t = 2.390, p = 0.024). Additionally, whilst the circulating number of CD31+ expressing TANG cells does not differ between young and older adults, there is a proportional shift in the CD4+ component, with a lower proportion of total CD4+ cells expressing CD31 in older group compared to younger adults. However, CRF status (high vs. low) did not affect the number of circulating TANG cells or VEGF-A expression in CD31+ T-cells (F(1,28) = 1.989, p = 0.170), (F(1,28) = 1.462, p = 0.237) and (F(1,28) = 1.011, p = 0.324) for CD3+CD31+, CD4+CD31+ and CD8+CD31+ T-cells respectively. Moreover, high cardiorespiratory fitness was associated with a lower proportion of CD8+CD31+ T-cells as a percentage of CD8+ T-cells. Moreover, older adults display elevated VEGF-A expression across all CD3+ subsets compared to younger people. In summary, age is associated with a shift in CD4+ TANG subsets, whilst CRF was found to be associated with a reduction in the proportion of CD8+ TANG cells.

Citation

Stephen, L. R. A. The effects of age and fitness status on circulating angiogenic T-cells. (Thesis). Edinburgh Napier University

• Thesis Type: Thesis
• Deposit Date: Sep 4, 2024
• Publicly Available Date: Sep 4, 2024
• DOI: https://doi.org/10.17869/enu.2024.3789805
• Award Date: Jul 3, 2024