Bariatric Surgery-Induced Weight Loss Reduces CD36 Expression in Association with the Improvement of Insulin Resistance in Monocytes of Obese Subjects

Abstract

Obesity is often associated with oxidative stress and lipid peroxidation, which are known risk factors for insulin resistance and type 2 diabetes. Cell differentiating-36 (CD36) is a cell membrane receptor that is also implicated in early stages of insulin resistance and diabetes due to its ability to bind and internalize oxidatively modified low-density lipoprotein (oxLDL). Bariatric surgery is an effective procedure that induces substantial weight loss and improves obesity-associated comorbidities. This study investigated the effect of Roux-en-Y Gastric Bypass Surgery (RYGB) on plasma oxLDL and CD36 expression and assessed possible link with insulin activity.

Th study was conducted prospectively in thirty-six obese subjects who underwent RYGB. Weight loss was recorded before and at 6 and 12 months postoperatively. The expression of CD36 in monocytes was analyzed by flow cytometry and polymerase chain reaction (PCR). The concentrations of blood lipids, glucose, insulin and oxLDL were assayed in plasma, and the homeostatic model assessment insulin resistance index (HOMA-IR) was determined.

There was a significant reduction of monocyte CD36 levels at 6 months (-48%) and 12 months (-63%) post-surgery. The concentrations of plasma insulin, oxLDL and triglycerides were reduced after 6 months (-38%, -41% and -29%, respectively) and after 12 months (-51%, -61% and -36%, respectively) post-surgery. The level of monocyte CD36 was positively correlated with body mass index (BMI), blood insulin and HOMA-IR.

The reduction of monocyte CD36 expression and plasma oxLDL level following RYGB-induced weight loss may contribute to the improvement of insulin resistance cardiovascular disease risk factors.