Although evidence suggests the link between chronic
inflammation and oxidative stress as the main mechanism responsible for endothelial dysfunction and cardiovascular complications in patients with
metabolic syndrome, little is known about the determining role of each
metabolic syndrome component in such alterations. This study investigated the relation between systemic oxidative alterations and
metabolic syndrome features in 41 patients. Compared with control subjects, serum
vitamin C and
alpha-tocopherol concentrations were lower and those of
lipid peroxides [
thiobarbituric acid reactive substances (
TBARs)] were higher in
metabolic syndrome patients (P < 0.001). A linear relation was observed between visceral fat thickness and serum
TBARs:
cholesterol ratio (r = 0.541, P < 0.001), whereas negative correlations were found between
alpha-tocopherol and BMI (r = -0.212, P < 0.05) and the grade of
liver steatosis (r = -0.263, P < 0.02). Patients with
metabolic syndrome and
liver steatosis had higher serum hyaluronate (HA) concentrations (P < 0.001). Serum HA was positively correlated with serum
alanine amino
transferase (r = 0.715, P < 0.001) and the homeostasis monitoring assessment index (r = 0.248, P < 0.03). The presence of
metabolic syndrome was predicted from a linear combination of visceral fat and all oxidative variables. In
metabolic syndrome patients, serum nitrosothiols and
vitamin C concentrations, which were lower (P < 0.001) than in control subjects, were inversely related to the grade of
hypertension (r = -0.645, P < 0.001 and r = -0.415, P < 0.007, respectively). In conclusion,
metabolic syndrome patients exhibited decreased
antioxidant protection and increased lipid peroxidation. Our results indicate a strong association between increased abdominal fat storage,
liver steatosis, and systemic oxidative alterations in
metabolic syndrome patients and diminished nitrosothiols and
vitamin C concentrations as important factors associated with
hypertension in these patients.