Adipose inflammation in obesity: relationship with circulating levels of inflammatory markers and association with surgery-induced weight loss.

CONTEXT: The inflammatory state of the adipose tissue is believed to contribute to systemic low-grade inflammation in obesity.

OBJECTIVE

This study assessed the relationship between adipose and circulating inflammatory markers as well as the influence of adipose inflammation on bariatric surgery-induced weight reduction.

DESIGN

This was a cross-sectional and longitudinal study (up to 14 mo).

SETTING

The study was conducted in the digestive/bariatric surgery department of the Tivoli and Jean Villar clinics, Bordeaux, France.

PATIENTS: Thirty-seven obese patients [body mass index (BMI)>35-40 kg/m2)] seeking bariatric surgery were included. Twenty-eight of them were successively followed up at 1-3 months after surgery and 25 between 6 and 14 months after surgery.

MAIN OUTCOME MEASURES: Fasting serum samples were collected before surgery to assess concentrations of inflammatory markers. Samples of visceral adipose tissue were extracted during surgery and gene expression of cytokines and immune cell markers were evaluated using quantitative RT-PCR. Pre- and postsurgery weight and BMI were collected.

RESULTS

Gene expression of several cytokines were strongly intercorrelated in the visceral adipose tissue. Adipose expression of macrophage and T cell markers were related to adipose expression of TNF-α and IL-1 receptor antagonist (P<.01) and to systemic levels of TNF-α (P<.01) and IL-6 (P<.05). A higher inflammatory state of the adipose tissue predicted a lower BMI reduction after surgery (P<.05), notably at early stages after surgery.

CONCLUSIONS

These findings support the involvement of macrophages and T cells in adipose inflammation and provide new information regarding the role of the visceral adipose tissue in the inflammatory state of obesity and its impact on obesity treatment outcomes, such as surgery-induced weight loss.