An obese brain and an inflamed body: Central and peripheral consequences of obesity

This PhD thesis addresses two topics in obesity. We describe three studies on striatal dopamine receptor (D⅔) availability in insulin resistant, morbidly obese women. We compared D⅔ availability between insulin resistant morbidly obese and healthy lean women and found lower striatal dopamine receptor availability in the obese. In addition we studied changes in D⅔ availability in the obese women before and after Roux-en-Y gastric bypass surgery (RYGB) and the relationship between D⅔ availability and eating behavior. We found an increase in striatal D⅔ availability >2 years after RYGB, without a correlation with improved eating behavior.
The second aim was to study the role of inflammation in insulin resistance. First we focused on short term effects of RYGB on hepatic, peripheral and adipose tissue insulin sensitivity. Next we studied the expression of pro- and anti-inflammatory markers in adipose tissue in relation to metabolic fluxes. Then we assessed the relation between the expression of retinol binding protein 4 (RBP4) in adipose tissue and liver and insulin sensitivity in obese women. Finally, we studied the relationship between inflammatory changes in liver tissue and hepatic insulin sensitivity as well as liver fat content.