Oxidative stress and serum paraoxonase activity in patients on maintenance hemodialysis

Incidence of atherosclerosis is high in hemodialysis (HD) patients. Paraoxonase may have protective effects against atherosclerosis as it prevents oxidative modification of LDL. Hence, the aim of the present study was to assess the lipid peroxidation and the antioxidant status including paraoxonase activity in HD patients. Thirty HD patients and thirty controls were included in the study. Serum malondialdehyde (MDA) was assessed as a marker of oxidative stress, while antioxidant status was assessed in terms of whole blood reduced glutathione, erythrocyte catalase and serum paraoxonase activity. A statistically significant (p < 0.001) rise of 196 % in serum MDA levels and decline of 36% in erythrocyte catalase activity was noted in HD patients as compared to controls. However, reduced glutathione (GSH) level in whole blood was not altered. Both basal and salt stimulated serum paraoxonase activities were reduced significantly (p < 0.001) as compared to controls with percentage decline of 53% and 37% in basal and salt stimulated paraoxonase activities respectively. These findings indicate that in addition to increased oxidative stress, reduced serum paraoxonase activity could also contribute to development of atherosclerosis in HD through increased oxidative modification of LDL.