Effects of Trans Fats, Obesity, and Type 2 Diabetes on the Immune System

  • Author / Creator
    Wadowski, Michael C.
  • Obesity is a major risk factor for the development of type 2 diabetes (T2D). While altered systemic inflammation is associated with the development T2D, the effects of obesity on immune function are not well known. It is not known why some obese individuals develop T2D, and some remain healthy. Dietary components may result in inflammation; relationships between industrially-produced trans fatty acids and inflammation have been established but there is a lack of research focusing on the effects of ruminant-derived trans fatty acids (conjugated linoleic acid (CLA) and vaccenic acid (VA)). The purpose of this study is to compare peripheral immune cell types and function between healthy obese and diabetic obese subjects, and to examine the effect of ruminant-derived trans fats on cytokine expression in adipose tissue of obese rats. Peripheral blood was obtained from healthy obese (n=10) and diabetic obese (n=9) subjects. Immune cell phenotypes were determined by flow cytometry. T cell proportions were not different between healthy obese and diabetic obese subject; however, diabetic obese subjects had a significantly higher (p<0.05) percentage of CD71-expressing T cells compared with healthy obese subjects. Diabetic subjects also had a significantly higher percentage of regulatory and naïve T cells. After stimulating with the polyclonal T cell mitogen phytohemagglutinin, cells from diabetic obese subjects produced less (P<0.05) IL-6 and TNF-α; IL-2 did not differ between the groups. Obese JCR:LA-cp rats (n=20) were fed a control, VA or CLA diet for 8 weeks. Perirenal fat pads were extracted and cytokine expression measured by qRT-PCR. Obese rats had higher expression (p<0.05) of TGF-β, IL-6, and IL-12 in adipose tissue compared to lean rats. Obese rats fed CLA had higher IL-6 expression in adipose tissue compared with rats fed the VA diet. These results suggest that when T2D accompanies obesity, T cell and neutrophil dysfunction occurs. Furthermore, naturally occurring trans fatty acids do not appear to exacerbate the production of cytokines in obese rats.

  • Subjects / Keywords
  • Graduation date
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
  • Language
  • Institution
    University of Alberta
  • Degree level
  • Department
    • Department of Agricultural, Food, and Nutritional Science
  • Specialization
    • Nutrition and Metabolism
  • Supervisor / co-supervisor and their department(s)
    • Field, Catherine (Agriculture, Food & Nutritional Science)
  • Examining committee members and their departments
    • Cameron, Lisa (Medicine)
    • Proctor, Spencer (Agriculture, Food & Nutritional Science)