Impact of Oxidative Stress in Premature Aging and Iron Overload in Hemodialysis Patients

Abstract

Background.Increased oxidative stress is a well described feature of patients in hemodialysis. Their need for multiple blood transfusions and supplemental iron causes a significant iron overload that has recently been associated with increased oxidation of polyunsaturated lipids and accelerated aging due to DNA damage caused by telomere shortening.Methods.A total of 70 patients were evaluated concomitantly, 35 volunteers with ferritin levels below 500 ng/mL (Group A) and 35 volunteers with ferritin levels higher than 500 ng/mL (Group B). A sample of venous blood was taken to extract DNA from leukocytes and to measure relative telomere length by real-time PCR.Results.Patients in Group B had significantly higher plasma TBARS (p=0.008), carbonyls (p=0.0004), and urea (p=0.02) compared with those in Group A. Telomeres were significantly shorter in Group B, 0.66 (SD, 0.051), compared with 0.75 (SD, 0.155) in Group A (p=0.0017). We observed a statistically significant association between relative telomere length and ferritin levels (r=-0.37,p=0.001). Relative telomere length was inversely related to time on hemodialysis (r=-0.27,p=0.02).Conclusions.Our findings demonstrate that iron overload was associated with increased levels of oxidative stress and shorter relative telomere length.