Oxidative stress in kidney transplant patients

Background. Little information is available about the role of oxidative stress in renal transplant patients. To evaluate the prevalence and severity of oxidative stress in renal transplantation, the authors conducted a cross-sectional study. Methods. In 112 cadaver or living-donor kidney transplant recipients with a follow-up of at least 6 months and with plasma creatinine less than or equal to 2.5 mg/dL, complete blood count, serum vitamin B-12, serum folate (s-F), reactive oxygen species (ROS), thiol groups (-SH), total antioxidant activity (TAOC), serum homocysteine (Hey), and intraerythrocyte folate (ery-F) were measured. Results. The mean levels of Hey (21.1 muM vs. <10 muM), ROS (302.7 U. Carr (Carratelli units) vs. 250-300 U. Carr), and TAOC (410.6 mumol/HclO/mL vs. >350 mumol/HclO/mL), were higher than the reference interval, whereas -SH groups, vitamin B-12, s-F, and ery-F were within the normal range. In the multivariate model, plasma creatinine (P=0.0062), vitamin B-12 (P=0.0121), and TAOC (P=0.0007) were independently associated with oxidative stress. At multiple regression analysis, -SH groups and ROS were directly and inversely related to hematocrit (P=0.0007 and P=0.0073). There was also a negative correlation between -SH groups and blood pressure levels (P=0.0095). Conclusions. Renal transplant patients have a pattern of increased oxidant stress that is counterbalanced by an enhancement of the antioxidant mechanisms. Besides the well-known risk factors, the authors found that anemia is an independent risk factor for an increase of ROS. Further studies are needed to evaluate whether the correction of anemia might prevent or reduce the oxidative stress in renal transplant patients.