Evaluation of the relationship between circulating omentin concentrations and components of the metabolic syndrome in nondiabetic adults without cardiovascular disease

Purpose: Omentin is a beneficial cytokine that is secreted by visceral adipose tissue and works to enhance insulin-stimulated glucose uptake in adipocytes.   Circulating omentin concentrations are decreased in patients with obesity, impaired glucose tolerance, and type 2 diabetes. However, little is known about circulating omentin concentrations in adults with the metabolic syndrome. The objective of this study was to evaluate the relationship between plasma omentin concentrations and components of the metabolic syndrome in nondiabetic adults without cardiovascular disease.

Methods: Blood samples were obtained from nondiabetic adults (n=124), ages 30-60 years, without cardiovascular disease. Subjects were classified as having the metabolic syndrome according to AHA/NHLBI criteria. Plasma omentin concentrations were analyzed by ELISA. Pearson’s correlations were used to determine the relationship between plasma omentin concentrations and components of the metabolic syndrome and clinical variables. Independent t tests and ANOVA were used for 2-group and 3-group comparisons, respectively.

Results: The study population was 54.8% women, 71.7% non-black, age 48 ± 8 years, BMI 31.2 ± 5 kg/m², and 65.3% with the metabolic syndrome. Plasma omentin concentrations were significantly correlated with waist circumference (r=−0.18, p=0.046) and systolic blood pressure (r=0.21, p=0.02). Plasma omentin concentrations were not significantly different between subjects with vs without the metabolic syndrome (151.0 ± 71.8 vs 157.0 ± 78.6 ng/ml, p=0.86). However, plasma omentin concentrations were 25% higher in lean compared with obese subjects (180.9 ± 59.5 vs 144.0 ± 70.2 ng/ml), although not statistically significant (p=0.24).

Conclusion: Our findings are consistent with data showing decreased omentin concentrations in obese states. We also found that plasma omentin concentrations were positively correlated with systolic blood pressure, which suggests that omentin may play a role in hypertension. Additional studies are needed to clarify the relationship between circulating omentin concentrations and components of the metabolic syndrome and hypertension in humans.