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.