Byproducts of oxidative protein damage and antioxidant enzyme activities in plasma of patients with different degrees of essential hypertension

Abstract

Despite evidence that essential hypertension (EH) is a state of increased oxidative stress, the data on oxidative protein modifications is lacking. Besides, the role of extracellular antioxidant enzymes in EH has not been systematically studied. Study was performed in 45 subjects with EH and 25 normotensive controls. Patients were divided into three groups according to the 2003 ESH/ESC guidelines (grade 1-3). Plasma protein reactive carbonyl derivatives (RCD) and SH-groups (as byproducts of oxidative protein damage) as well as antioxidant enzyme activities superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase were studied spectrophotometrically and correlated with blood pressure (BP). RCD levels were increased in EH patients compared to controls and correlated significantly with both systolic blood pressure (SBP) (r ¼ 0.495, Po0.01) and diastolic blood pressure (DBP) (r ¼ 0.534, Po0.01). Plasma SH-groups content was significantly lower in all patients with EH, with no correlation with BP. SOD and catalase activity in patients with grade 1 EH were similar to that of controls. Patients with grade 2 and 3 of EH had lower SOD and catalase activity. However, significant correlation with SBP and DBP was observed for catalase only (r ¼ À0.331; Po0.05 and r ¼ À0.365; Po0.05, respectively). EH patients exhibited higher plasma GPX activity compared to those in controls, and it correlated with SBP (r ¼ 0.328; Po0.05). The results presented show that increased oxidative protein damage is present in all grades of EH. In mild hypertension extracellular antioxidant enzyme activities are not decreased, suggesting they are probably not critical in early EH, but could be important in moderate to severe EH.

Impact of the components of metabolic syndrome on oxidative stress and enzymatic antioxidant activity in essential hypertension

“…To assess OX, a large battery of tests including not only the oxidized over the GSH but also measurement of ROS-derived products from lipid peroxidation, 20 proteins, 21 and from the repair of genomic and mitochondrial DNA was used. A large number of parameters for assessment of OX have been used, and no recommendation about what is the best is available now.…”

Reactive oxygen species and vascular biology: implications in human hypertension

“…Hypertensive patients have reduced activity and decreased content of antioxidant enzymes, including SOD, glutathione peroxidase and catalase. 157,158 Decreased levels of antioxidant vitamins A, C and E have been demonstrated in newly diagnosed, untreated hypertensive patients compared with normotensive controls. 158 Moreover, SOD activity has been demonstrated to correlate inversely with blood pressure in patients with hypertension.…”

“…157,158 Decreased levels of antioxidant vitamins A, C and E have been demonstrated in newly diagnosed, untreated hypertensive patients compared with normotensive controls. 158 Moreover, SOD activity has been demonstrated to correlate inversely with blood pressure in patients with hypertension. 158 In patients with white coat hypertension serum protein carbonyl (indicating protein oxidation) was increased and endogenous antioxidant proteins (protein thiol, SOD, glutathione) were decreased compared with normotensive individuals, suggesting a relationship between oxidative stress and hypertension.…”

“…158 Moreover, SOD activity has been demonstrated to correlate inversely with blood pressure in patients with hypertension. 158 In patients with white coat hypertension serum protein carbonyl (indicating protein oxidation) was increased and endogenous antioxidant proteins (protein thiol, SOD, glutathione) were decreased compared with normotensive individuals, suggesting a relationship between oxidative stress and hypertension. 159 Antioxidant vitamins reduced blood pressure and arterial stiffness in patients with diabetes or hypertension in small clinical studies, 160 but had no effect in postmenopausal women, in healthy subjects or in pregnant women at risk for hypertension/preeclampsia.…”

Reactive Oxygen Species, Vascular Noxs, and Hypertension: Focus on Translational and Clinical Research

“…Patients with essential hypertension exhibit reduced activity and decreased plasma levels of antioxidant enzymes, including SOD, glutathione peroxidase, and catalase (192). Decreased levels of antioxidant vitamins A, C, and E have been shown in newly diagnosed, untreated hypertensive patients compared with normotensive controls (143).…”