Discriminatory metabolic and inflammatory parameters in serum and omental adipose tissue of obese patients with different insulin sensitivity

Objective: Metabolically healthy obese phenotype is defined by high insulin sensitivity and lack of metabolic syndrome, parameters regulated by omental adipose tissue inflammation, ectopic fat deposition and adipose tissue dysfunction. Our study aimed to identify novel metabolic and inflammatory markers in serum and omental adipose tissue which characterize the “unhealthy” obese patients and distinguish them from obese patients with better metabolic profile. Design: Cross-sectional study. Patients: Subjects included 75 obese patients undergoing bariatric surgery at the Tel-Aviv Medical Center (mean age 43.9 ± 13.9, mean BMI 41 ± 8.4). The HOMA median value was used as a cut-off to differentiate between patients with better or worse insulin resistance. Measurements: Demographic data, fasting serum insulin, glucose, bile acids, serum metabolic and inflammatory markers were obtained. During the bariatric surgery, omental adipose tissue was harvested and analyzed for metabolic and inflammatory markers using qRT-PCR. Logistic regressions were used to calculate odds ratio and 95% confidence interval for the prediction of the metabolic profile. Results: Serum markers that were significantly higher among the obese with HOMA >6 were total bile acids. In the omental adipose tissue the inflammatory markers TNFα and ADAM17 were significantly higher among obese patients with HOMA >6. In multivariate analysis, the strongest predictor for insulin resistance was ADAM17 (OR = 1.82, 1.06–3.14, P = 0.031). Conclusions: The study highlighted the predictive value of serum bile acids in identifying obese patients at high risk. Secondly, omental adipose tissue ADAM17 was revealed as a novel and strongest independent predictor for higher insulin resistance in morbidly obese patients.