Circulating endothelial cells (CECs) and endothelial progenitor cells (EPCs) are sensitive markers of cardiovascular damage and repair, respectively. The aim of this thesis was to advance the state of knowledge regarding CECs and EPCs, and the factors affecting their concentrations, in children and adolescents.
The first and second studies demonstrated that CECs and EPCs were similar when participants were split by sex, chronological age (8-10 vs. 14-16 years), and biological age (≤ -1 vs. ≥ +1 year from peak height velocity). Moreover, CECs, but not EPCs, were positively associated with aerobic fitness and negatively related to daily moderate-to-vigorous physical activity. Neither CECs nor EPCs were related to level of adiposity. Although there was a large degree of inter-individual variability in both cell types, most of our data were clustered towards one end of the reported range. These observations highlighted the need to examine these cells in children with chronic conditions associated with an increased risk of poor cardiovascular health. Therefore, CECs and EPCs were examined at rest and in response to acute exercise in juvenile idiopathic arthritis (JIA) and healthy controls. Resting levels of CECs and EPCs were similar in both groups, which may be attributable to the low disease activity in the participants with JIA. High intensity, intermittent exercise (HIIE) and moderate intensity, continuous exercise (MICE) had no effect on CECs in both groups. Conversely, MICE led to a robust increase in EPCs in healthy controls; no such change was observed in youth with JIA.
This thesis represents the first comprehensive assessment of CECs and EPCs in the context of fitness, physical activity, and acute exercise in children and adolescents. Future research should examine the function and fate of these cells in youth, as well as the potential mechanisms underlying the blunted EPC response to exercise in JIA. / Thesis / Doctor of Philosophy (PhD) / Fitness and physical activity are critical for maintaining and improving cardiovascular health in children and adults. We don’t know exactly how they do this but the evidence in adults suggests it may be related to rare cells in the blood involved in repairing damaged blood vessels. The main objective of this thesis was to learn more about these cells, called circulating endothelial cells and endothelial progenitor cells, in children. We found that only circulating endothelial cells were related to fitness and physical activity. We also found that endothelial progenitor cells increased when healthy children performed 60 minutes of cycling. On the other hand, these cells did not change when children with juvenile idiopathic arthritis performed the same exercise. More research is needed to determine exactly why these cells responded to exercise in healthy but not sick children, and to help us identify the optimal exercise to improve these cells in youth.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/18300 |
| Date | 11 1900 |
| Creators | Obeid, Joyce |
| Contributors | Timmons, Brian W., Kinesiology |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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