Association of Serum Antioxidant Enzymes and Nervous Tissue Markers in Hypertensive Patients

Abstract

Background and Purpose: Hypertension has serious effects on cerebral blood vessels. Oxidative stress seems to be implicated in blood pressure elevation, through increased reactive oxygen species and/or decreased antioxidant capacity. Recently blood markers indicating damage to the central nervous system were reported to be increased in hypertensive patients. However, it is unknown whether antioxidant capacity is related to these changes. This study was designed to explore if the concentration of blood markers for nervous tissue damage was associated to antioxidant capacity in hypertensive patients. Methods: Twenty hypertensive patients and 23 healthy controls were studied. They were paired by age, sex, ethnicity, or risk factors. Serum neuron specific enolase (NSE) and S100 calcium binding protein B (S100B) were measured as nervous tissue damage markers, as well as the activity of antioxidant enzymes (catalase, glutathione peroxidase, glutathione reductase and gamma-glutamyltransferase). Results: Serum neuronal specific enolase (NSE) and S100 calcium binding protein B (S100B) concentrations determined by immunoassay were significantly increased in patients vs. controls. The activities of antioxidant enzymes measured by spectrophotometry showed that plasmatic catalase and erythrocytic glutathione peroxidase were significantly increased in patients, but erythocytic catalase was decreased. Gammaglutamyltransferase activity was significantly correlated with S100B in hypertensive patients, while erythrocytic catalase activity was decreased in subjects with higher NSE levels. Conclusion: This preliminary investigation suggested that antioxidant status might be modulated through changes in antioxidant enzymatic activity in hypertensive patients. The association of some of these M. Peña-Sánchez et al. 161 changes with peripheral markers of damage to the central nervous system could indicate that the increased levels of these proteins in hypertension are partly related to oxidative stress.