Shang-Chih Liao

Mitochondrial DNA copy number correlates with oxidative stress and predicts mortality in nondiabetic hemodialysis patients

BACKGROUNDnOxidative stress is highly prevalent in hemodialysis patients and may contribute to atherosclerosis and mortality. The copy number of mitochondrial DNA (mtDNA) is affected by oxidative stress in blood circulation. This study aimed to test whether mtDNA copy number correlates with oxidative stress and predicts all-cause mortality in nondiabetic hemodialysis patients.nnnMETHODSnNinety-five nondiabetic hemodialysis patients and 95 healthy subjects were enrolled. Plasma thiobarbituric acid-reactive substances (TBARS) and plasma free thiol were used as indicators of oxidative stress and antioxidant defense, respectively. Mitochondrial DNA copy number in peripheral blood leukocytes was measured by determining relative amounts of mtDNA to nuclear DNA by quantitative real-time PCR. All-cause mortality of hemodialysis patient was recorded during a follow-up of 3 years.nnnRESULTSnNondiabetic hemodialysis patients showed higher TBARS levels, lower free thiol levels and higher mtDNA copy numbers compared with normal control subjects. The plasma TBARS level was a significant factor correlating positively to the mtDNA copy number (p=0.024). Patients with a mtDNA copy number higher than the median had a higher all-cause mortality than patients with a lower mtDNA copy number (17.0% vs. 4.2%; log-rank test: p=0.038). A 1-log increase in mtDNA copy number was independently related to an increase in the risk for mortality (hazard ratio 21.360; 95% confidence interval, 1.298-351.572).nnnCONCLUSIONSnNondiabetic hemodialysis patients had higher oxidative stress and mtDNA copy numbers than healthy subjects. The mtDNA copy number correlates with oxidative stress and predicts mortality in nondiabetic hemodialysis patients.

Relationship between Kt/V urea-based dialysis adequacy and nutritional status and their effect on the components of the quality of life in incident peritoneal dialysis patients

BackgroundIt is well known that the quality of life of patients with chronic kidney disease can be improved by dialysis. While previous studies have used retrospective designs and adhered to a standard target prescribed by clinical guidelines, our study prospectively investigates the association between the adequacy of peritoneal dialysis (PD) and measures of nutritional status on quality-of-life domains in a cohort of incident PD patients.MethodsIt was a prospective 6-month observational study. Eighty incident PD participants who were treated in a hospital-based PD center were enrolled. The period of enrollment was January 2009–June 2010; follow-up continued until December 2010. PD adequacy indices, including Kt/V urea, weekly Ccr (WCcr), measures of nutritional status (albumin, BMI), and nPCR were measured at 1 month and 6 months after PD initiation. SF-36 health survey questionnaires were used to measure the quality of life. The outcomes were used to measure the changes in the domains of the SF-36 after 6 months of PD therapy.ResultsSeventy-seven incident patients who underwent PD for 6 months were included in the study. The mean age was 47.3 years, and the male-to-female ratio was 38:39. A peritoneal Kt/V urea value of 1.2, which was also the baseline cutoff value, was found to have the highest influence on SF-36 domains. Patients with baseline peritoneal Kt/V urea value of <1.2 showed improvement in the physical functioning and role limitation of physical functioning components after 6 months of PD. In contrast, patients with baseline peritoneal Kt/V urea values of ≥1.2 showed remarkable improvement in the general health, physical functioning, role limitation caused by physical problems, and bodily pain components. However, the trend of improvement decreased in patients with baseline nPCR of <1.2. Baseline renal WCcr did not influence the improvement in the SF-36 domains.LimitationsA small cohort and a short observation period.ConclusionsThe baseline level of peritoneal Kt/V urea affected the components of the quality of life after PD initiation. In contrast, a lower baseline nPCR level was associated with deterioration in the quality of life after PD therapy.