P-282: Antioxidant enzymes in lymphocites from essential hypertension patients

An increment in oxidative status and oxidative byproducts and a decrease in the activity of antioxidant enzymes reversible with antihypertensive treatment has been described in essential hypertension. Objective: The objective was to evaluate if the reduced activity of antioxidant enzymes was the consequence of a low mRNA expression or an excessive enzyme degradation. Design and Methods: Seventeen essential hypertensive patients, 10 in absence and 8 during antihypertensive treatment, and 10 normotensive controls were included. Antioxidant enzymatic activity of superoxide dismutase (SOD), catalase and glutathion peroxidase, and mRNA expression of these enzymes were assessed in lymphocites obtained from peripheral blood. The mRNA expression was measured by cuantitative real-time PCR. Results: In untreated hypertensive subjects activity of the SOD, Catalase and Glutathion Peroxidase were significantly lower than those observed in controls. After three months of antihypertensive treatment an increase in the enzymatic activity has been observed. The simultaneous estimation of the SOD mRNA expression showed that it was significantly higher in hypertensive subjects than those observed in controls. The higher expression was maintained during the antihypertensive treatment. In contrast catalase and glutathion peroxidase mRNA expression was significantly lower in the untreated hypertensives as compared to the controls. Antihypertensive treatment increases the mRNA expression and the activity of these enzymes. Conclusions: In lymphocytes of hypertensive patients, the low activity of SOD despite the high mRNA expression, indicates that was the result of an excessive enzyme degradation in response to a high oxidative stress status. The behaviour of the other antioxidant enzymes follow a different pattern. The better knowledge of these processes can improve our understanding of the relationship between hypertension and oxidative stress.