The Inflammatory Effects of Glucose and Lipids on Granulocytes and Monocytes of Healthy, Obese, and Type II Diabetic Subjects

The goal of this project was to identify the metabolic compounds which play a role in the exacerbation of chronic inflammation described in obesity and type 2 diabetes (T2DM). The cardiovascular complications of obesity and T2DM are associated with underlying atherosclerosis resulting in an increased risk of mortality compared to the healthy population. The acceleration of atherosclerosis has been closely related to chronic inflammatory processes in which the innate immune system plays a pivotal role. Systemic activation of granulocytes (Gc) and monocytes (Mc) increase the rate of atherosclerotic plaque formation elevating the risk for ischemia in the surrounding tissues. The importance of this project lies in identifying some of the specific metabolic compounds and mechanisms responsible for the increased activation levels of innate immune system cells in obesity and T2DM. If these processes are clarified, serious cardio and cerebro-vascular complications could be treated with targeted therapeutic approaches potentially offering better efficacy and fewer side-effects compared to current methods. This dissertation contains the results of 20 ex vivo and 45 in vivo studies in which the activation of Gc and Mc of healthy, obese and T2D subjects have been evaluated during glucose, lipid, and glucose+lipid exposure. Changes in the expression of cell surface markers associated with innate immune cell activation have been measured by flow cytometry; the systemic release of inflammatory cytokines and chemokines have by Enzyme-linked Immunosorbent Assay (ELISA); and innate immune cell gene expression related to cell activation by RT-PCR. The ex vivo results indicate that hyperglycemic T2D have higher expression of Gc and Mc surface activation markers compared to T2DM subjects with normal blood sugar and healthy subjects. In addition, in vivo infusion studies show that the cell surface expression of Gc and Mc activation markers increases in all subjects during lipid and glucose+lipid infusion, but more so in T2DM subjects. Lipid and glucose+lipid but not glucose alone also elevated circulating pro- and anti-inflammatory proteins in the plasma of obese and T2D subject, but not in healthy subjects. Finally, there was no change in proinflammatory gene expression associated with surface markers and circulating chemokines during either infusion treatments in PBMC's of any of the three groups.;Overall, the data shows that although both glucose and lipid have activating effects on Gc and Mc marked by surface adhesion markers and circulating proteins, the level of inflammatory activation may strongly modulated by the subject's overall metabolic status.