Oxidative stress in the pathophysiology of metabolic syndrome: which mechanisms are involved?

Estresse oxidativo na fisiopatologia da síndrome metabólica: quais mecanismos estão envolvidos?

ABSTRACT

Metabolic syndrome (MS) is a combination of cardiometabolic risk factors, including obesity, hyperglycemia, hypertriglyceridemia, dyslipidemia and hypertension. Several studies report that oxidative condition caused by overproduction of reactive oxygen species (ROS) plays an important role in the development of MS. Our body has natural antioxidant system to reduce oxidative stress, which consists of numerous endogenous and exogenous components and antioxidants enzymes that are able to inactivate ROS. The main antioxidant defense enzymes that contribute to reduce oxidative stress are superoxide dismutase (SOD), catalase (CAT) and gluthatione peroxidase (GPx). The high-density lipoprotein cholesterol (HDL-c) is also associated with oxidative stress because it presents antioxidant and anti-inflammatory properties. HDL-c antioxidant activity may be attributed at least in part, to serum paraoxonase 1 (PON1) activity. Furthermore, derivatives of reactive oxygen metabolites (d-ROMs) also stand out as acting in cardiovascular disease and diabetes, by the imbalance in ROS production, and close relationship with inflammation. Recent reports have indicated the gamma-glutamyl transferase (GGT) as a promising biomarker for diagnosis of MS, because it is related to oxidative stress, since it plays an important role in the metabolism of extracellular glutathione. Based on this, several studies have searched for better markers for oxidative stress involved in development of MS.

Key words:
metabolic syndrome X; reactive oxygen species; antioxidants; HDL cholesterol; gamma-glutamyl transferase