The overall aim of the work presented in this thesis was to further characterise aspects of metabolic and immune system cross-talk in human subcutaneous adipose tissue, with a particular emphasis on the potential role of T-lymphocytes in adipose tissue dysfunction and insulin resistance. Chapter 3 characterised macrophage and T-lymphocyte populations residing in adipose tissue from lean through to class I obese men. This work demonstrated that T-lymphocytes display increased activation with increased adiposity and that potential compensatory mechanisms may be present to help counteract adipose tissue inflammation. In Chapter 4, the same participants were exposed to a meal-based stimulus in order to examine the postprandial metabolic and inflammatory responses in blood and adipose tissue. Despite increased glucose and insulin responses in blood with obesity, there were no differences in inflammatory cytokine gene expression responses in adipose tissue. This suggests that mechanisms may be present to limit or dampen inflammatory output from adipose tissue after feeding in individuals with modestly increased adiposity. Chapter 5 examined metabolic and immune system changes to 50 % calorie restriction for 3 days, resulting in reduced serum leptin which was temporally associated with a reduction in blood T-lymphocyte activation. In adipose tissue, however, leptin gene expression/secretion was not reduced and neither was resident T-lymphocyte activation, indicating that there may be local tissue-specific responses of immune cells to caloric restriction. Chapter 6 characterised differences between obese individuals with either normal or impaired glucose tolerance, and their respective responses to 10 days of diet and activity modification. Overall, this thesis highlights key differences in properties of T-lymphocyte populations with increasing levels of adiposity and insulin resistance together with responses in adipose tissue and the immune system in times of feeding, severe calorie restriction and glucose lowering diet and activity.
|Date of Award||25 Feb 2015|
|Supervisor||Dylan Thompson (Supervisor) & James Betts (Supervisor)|
- Adipose tissue
- Insulin resistance