Endoplasmic Reticulum Stress Is Reduced in Tissues of Obese Subjects After Weight Loss

OBJECTIVE—Obesity is associated with insulin resistance and type 2 diabetes, although the mechanisms linking these patholo-gies remain undetermined. Recent studies in rodent models revealed endoplasmic reticulum (ER) stress in adipose and liver tissues and demonstrated that ER stress could cause insulin resistance. Therefore, we tested whether these stress pathways were also present in obese human subjects and/or regulated by weight loss. RESEARCH DESIGN AND METHODS—Eleven obese men and women (BMI 51.3 3.0 kg/m2) were studied before and 1 year after gastric bypass (GBP) surgery. We examined systemic insulin sensitivity using hyperinsulinemic-euglycemic clamp studies before and after surgery and collected subcutaneous adipose and liver tissues to examine ER stress markers. RESULTS—Subjects lost 39 9 % body wt at 1 year after GB