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Antioxidant activities and oxidative stress byproducts in human hypertension
Josep Redón1, Maria R Oliva, Carmen Tormos
1Department of Biochemistry and Molecular Biology, Medical School, University of Valencia, Avda Blasco Ibañez 17, 46010 Valencia, Spain.
Insights
Hypertensive patients exhibit increased oxidative stress and reduced antioxidant defenses in blood and cells, independent of blood pressure levels. This study highlights systemic oxidative imbalance in hypertension.
Area of Science:
- Biochemistry
- Cardiovascular Physiology
- Oxidative Stress Research
Background:
- Hypertension is a major risk factor for cardiovascular diseases.
- Oxidative stress plays a role in hypertension pathogenesis.
- Understanding oxidative status in hypertension is crucial for therapeutic strategies.
Purpose of the Study:
- To investigate oxidative status and antioxidant activities in whole blood and peripheral mononuclear cells (PMCs) of hypertensive patients.
- To examine the relationship between oxidative stress markers and blood pressure levels.
- To assess reactive oxygen species (ROS) byproducts in hypertension.
Main Methods:
- Studied 66 hypertensive patients and 16 normotensive controls.
- Measured oxidized/reduced glutathione ratio, malondialdehyde (MDA), superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPx) activity.
- Assessed 8-oxo-2 -deoxyguanosine (8-oxodG) levels in nuclear and mitochondrial DNA.
Main Results:
- Hypertensive patients showed significantly higher oxidized/reduced glutathione ratio and MDA.
- Activity of SOD, catalase, and GPx was significantly lower in hypertensive subjects.
- 8-oxodG content was significantly higher in hypertensive subjects' DNA.
- No correlation found between blood pressure tertiles/types and oxidative stress markers.
- Oxidative stress markers were independent of 24-hour mean blood pressure.
Conclusions:
- Hypertensive individuals exhibit increased oxidative stress and diminished antioxidant capacity in blood and PMCs.
- These alterations in oxidative status appear independent of blood pressure values in hypertensive patients.
- Findings suggest a systemic oxidative imbalance contributing to hypertension, irrespective of specific blood pressure readings.
Abstract:
The objective was to study oxidative status, antioxidant activities, and reactive oxygen species byproducts in whole blood and mononuclear peripherals cells and their relationship with blood pressure. Sixty-six hypertensive patients and 16 normotensive volunteers as a control group were studied. In both, whole blood and peripheral mononuclear cells oxidized/reduced glutathione ratio and malondialdehyde was significantly higher, and the activity of superoxide dismutase, catalase, and glutathione peroxidase was significantly lower in hypertensive patients when compared with normal subjects. The content of damaged base 8-oxo-2'-deoxyguanosine in nuclear and mitochondrial deoxyribonucleoproteins of hypertensive subjects was also significantly higher than that of the normotensive control subjects. No differences in these measurements were found among hypertensive subjects grouped in tertiles of 24-hour average mean blood pressure or between "white-coat" and established hypertensive subjects. Furthermore, no relationship was observed between the average of 24-hour mean blood pressure and oxidized/reduced glutathione ratio, reactive oxygen species byproducts, malondialdehide, or genomic 8-oxo-2'-deoxyguanosine. In whole blood and in mononuclear cells from hypertensive subjects, there was an increase in oxidative stress and a reduction in the activity of antioxidant mechanisms that appeared to be independent of the blood pressure values.