61 An Association of Oxidative Stress Biomarkers and Mitochondrial DNA Copy Number in Chronic Dialysis Patients

AN ASSOCIATION OF OXIDATIVE STRESS BIOMARKERS AND MITOCHONDRIAL DNA COPY NUMBER IN CHRONIC DIALYSIS PATIENTS Jin-Bor Chen, Wen-Chin Lee, Chien-Chun Kuo, Ben-Chung Cheng, Shang-Chih Liao Division of Nephrology, Chang Gung Memorial HospitalKaohsiung Medical Center, Taiwan The purpose of study is to investigate the association of mitochondrial biogenesis and oxidative stress in chronic dialysis patients. A total of 199 chronic dialysis patients (hemodialysis: 111, peritoneal dialysis: 88) (mean age 48.9 year-old, male/female, 80/119) and 213 healthy control (mean age 49.4 year-old, male/female, 83/130) were enrolled as investigated subjects. Demographic, hematological, biochemical data, oxidative stress biomarkers, mitochondrial (mt) DNA copy number were compared between two groups. Plasma thiobarbituric acid-reactive substances (TBARS) and plasma free thiols were measured as indicators of oxidative damage to plasma lipids and antioxidant defense, respectively. mt DNA copy number in peripheral blood leukocytes was determined by calculating the relative mtDNA amount to the nuclear DNA by quantitative polymerase chain reaction. The mt DNA copy number were expressed by transforming to log values. The results showed dialysis patients had higher serum BUN, Cr, P, K, triglyceride levels, and lower Hb, albumin, cholesterol levels than control. TBARS levels (1.09 vs 0.77 uM/L, p=0.00) and mt DNA copy number (2.92 vs 2.54, p=0.00) were higher in dialysis patients than control. Free thiols levels were lower in dialysis patients (1.5 vs 2.12 uM/L, p=0.00) compared to control. The mt DNA copy number in dialysis patients were correlated with age, free thiols levels, body height (Pearson correlation). However, diabetes, cardiac disease, hypertension, stroke did not show positive impact on mt DNA copy number. In conclusion, chronic dialysis patients showed an increased oxidative stress status and thus leading to compensatory increased mt DNA copy number.