Correlation of oxidative stress biomarkers and peritoneal urea clearance with mitochondrial DNA copy number in continuous ambulatory peritoneal dialysis patients.
OBJECTIVE
The influence of oxidative stress and peritoneal clearance on alterations in mitochondrial DNA (mtDNA) copy number in continuous ambulatory peritoneal dialysis (CAPD) patients was investigated.


METHODS
Ninety-one CAPD patients (age, 30-57 years) and 99 age-matched healthy subjects were enrolled. Biochemical variables, plasma thiobarbituric-acid-reactive substances (TBARS), free thiol levels and mtDNA copy number in peripheral leukocytes were measured.


RESULTS
CAPD patients showed higher TBARS levels, lower free thiol levels and a higher mtDNA copy number than control subjects. Plasma TBARS levels and peritoneal urea clearance were significant factors contributing positively to leukocyte mtDNA copy number (p = 0.024, R(2) = 0.238). The CAPD patients were further categorized into 4 groups depending on whether the TBARS and free thiol plasma levels were above or below the mean values for these parameters. Patients with higher TBARS levels and lower free thiol levels had a significantly higher number of leukocyte mtDNA copies than patients with lower TBARS levels and higher free thiol levels (multi-covariate ANOVA, p = 0.008).


CONCLUSIONS
This study demonstrated that CAPD patients have higher oxidative stress than healthy subjects; such elevated oxidative stress and peritoneal urea clearance have a positive correlation with mtDNA copy number in peripheral leukocytes.
Nephrology Division, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan, ROC.
Jin-Bor
JB
Chen
Tsu-Kung
TK
Lin
Chia-Wei
CW
Liou
Shang-Chih
SC
Liao
Lung-Chih
LC
Lee
Pei-Wen
PW
Wang
Mao-Meng
MM
Tiao
D000328:Adult; D015415:Biomarkers / Q000097:blood*; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D018628:Gene Dosage; D006801:Humans; D007962:Leukocytes; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000502:physiology*; D010531:Peritoneal Dialysis, Continuous Ambulatory; D013438:Sulfhydryl Compounds / Q000097:blood; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis; D014508:Urea / Q000378:metabolism*
D015415:Biomarkers; D004272:DNA, Mitochondrial; D013438:Sulfhydryl Compounds; D017392:Thiobarbituric Acid Reactive Substances; D014508:Urea