Influence of metabolic syndrome on biomarkers of oxidative stress and inflammation in obese adults.

OBJECTIVE: Both obesity and the metabolic syndrome (MetS) have been independently linked with increased oxidative and inflammatory stress. This study tested the hypothesis that obesity with MetS is associated with greater oxidative and inflammatory burden compared with obesity alone.

RESEARCH METHODS AND PROCEDURES: Forty-eight normal-weight and 40 obese (20 without MetS; 20 with MetS) adults were studied. MetS was defined according to National Cholesterol Education Program Adult Treatment Panel III criteria. Plasma concentrations of oxidized low-density lipoprotein, C-reactive protein, tumor necrosis factor-alpha, interleukin (IL)-6, and IL-18 were determined by enzyme immunoassay.

RESULTS: Plasma biomarkers of oxidative stress and inflammation were lowest in normal-weight controls. Of note, obese MetS adults demonstrated significantly higher plasma concentrations of oxidized low-density lipoprotein (62.3 +/- 3.2 vs. 54.0 +/- 4.0 U/L; p < 0.05), C-reactive protein (3.0 +/- 0.6 vs. 1.5 +/- 0.3 mg/L; p < 0.01), tumor necrosis factor-alpha (2.1 +/- 0.1 vs. 1.6 +/- 0.1 pg/mL; p < 0.05), IL-6 (2.8 +/- 0.4 vs. 1.4 +/- 0.2 pg/mL; p < 0.01), and IL-18 (253 +/- 16 vs. 199 +/- 16 pg/mL; p < 0.01), compared with obese adults without MetS.

DISCUSSION: These results suggest that MetS heightens oxidative stress and inflammatory burden in obese adults. Increased oxidative and inflammatory stress may contribute to the greater risk of coronary heart disease and cerebrovascular disease in obese adults with MetS.