P-653: Oxidative stress and enzymatic antioxidant mechanisms in essential hypertension

The objective was to evaluate the oxidative status, the extent of lipid and DNA oxidation and the activity of enzymatic antioxidants in essential hypertensive patients out of antihypertensive treatment. Forty-one essential hypertensive subjects (mean age 48 yr, 24 males, SBP 160±18 mmHg, DBP 97±12 mmHg), and 10 normotensive controls were included. According 24h ABP hypertensives were grouped in those with isolated clinic hypertension (ISCH) and true hypertensives (HTN). In whole blood and in lymphocites, oxidative stress status (GSSG/GSH), lipid-perodixation product (malondialdehyde), DNA-damage (8-oxo-2'-deoxyguanosine only in lymphocites) and the activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (Gpx) were measured in absence of antihypertensive treatment. All hypertensive subjects shown a significative increase in the GSSG/GSH index as well as in the levels of malondialdehyde or 8-oxo-2'-deoxyguanosine. Subjects with ISCH shown higher GSSG/GSH, malondialdehyde and 8-oxo-2'-deoxyguanosine than the controls did, but lower than those observed in HTN. A decreased activity of the three enzymatic systems, SOD, CAT and Gpx measured were observed in all hypertensive subjects, both ISCH and HTN. Conclusion: Essential hypertension is associated with greater than normal oxidative stress partially related to ambulatory BP levels. Furthermore an imbalance in anti-oxidant status was present in hypertensive subjects.