Comparison of oxidative stress biomarkers in hypertensive patients with or without hyperhomocysteinemia

Hyperhomocysteinemia is an independent risk factor for cardiovascular impairment in hypertension. Oxidative stress is important in the molecular mechanisms associated with hypertension, but there are few studies focusing on the comparison of oxidative stress biomarkers in hypertensive patients with or without hyperhomocysteinemia. The study included 50 newly diagnosed hypertensive patients with hyperhomocysteinemia, 50 newly diagnosed hypertensive patients without hyperhomocysteinemia, and 50 age-matched healthy controls. Serum levels of malondialdehyde, nitric oxide, 8-isoprostane-F2_ɑ, superoxide dismutase, catalase, and glutathione peroxides were compared. Levels of malondialdehyde and 8-isoprostane-F2_ɑ were higher in both hypertensive groups than in the control group (8.3 ± 1.8 μmol/L vs. 6.5 ± 1.3 μmol/L vs. 4.3 ± 1.2 μmol/L, P < 0.05; 23.5 ± 12.1 pg/mL vs. 17.4 ± 10.3 pg/mL vs. 13.9 ± 7.5 pg/mL, P < 0.05), while levels of superoxide dismutase and catalase were lower in both hypertensive groups than in the control group (120.5 ± 13.7 U/mL vs. 131.3 ± 18.2 U/mL vs. 149.1 ± 14.6 U/mL, P < 0.05; 23.8 ± 7.4 U/mL vs. 24.6 ± 9.2 U/mL vs. 33.5 ± 8.2 U/mL, P < 0.05). In hypertensive subgroups, serum malondialdehyde levels were higher in the hyperhomocysteinemia group than the other group (8.3 ± 1.8 μmol/L vs. 6.5 ± 1.3 μmol/L; P < 0.05), and superoxide dismutase activities were lower in the hyperhomocysteinemia group than the other group (120.5 ± 13.7 U/mL vs. 131.3 ± 18.2 U/mL; P < 0.05). Moreover, in hypertensive patients, homocysteine levels were significantly correlated with malondialdehyde (r = 0.39, P < 0.01), 8-isoprostane-F2ɑ (r = 0.47, P < 0.05), superoxide dismutase (r = -0.51, P < 0.01), and catalase (r = -0.51, P < 0.05), respectively. Our findings demonstrated oxidative stress was more severe in hypertensive patients with hyperhomocysteinemia than those hypertensive patients without it. Besides, there were strong relationships between homocysteine activities and oxidative/antioxidative parameters, which indicated that homocysteine might aggravate the oxidative stress in hypertension to produce contributory effects on cardiovascular impairment.