Useful markers for detecting decreased serum antioxidant activity in hemodialysis patients

This study evaluates a novel application of a method for measuring serum antioxidant activity, based on the detection of erythrocyte membrane lipid peroxidation in cases of uremia. A human erythrocyte ghost membrane in Tris-HCl was mixed with adenosine 5'-diphosphate and iron chloride (FeCl3; ADP/Fe3+) solution (at a molar ratio of 17:1), and the mixture was incubated under aerobic conditions at 37 degrees C for 2 hours. The concentration of erythrocyte membrane thiobarbituric acid-reactive substances increased proportionally with respect to ADP/Fe3+ concentration, and this increase was inhibited by serum albumin in a dose-dependent manner. In patients undergoing chronic hemodialysis therapy, predialytic sera contained in this reaction mixture were weaker than postdialytic sera in terms of inhibitory effect against erythrocyte membrane lipid peroxidation, whereas serum albumin contents remained at levels equivalent to those of the normal control. A gradual increase in human mercaptalbumin nonmercaptalbumin ratio during hemodialysis treatment might be one of the major factors that leads to the recovery of decreased serum antioxidant activity. We clearly showed that the serum scavenging activity against erythrocyte membrane lipid peroxidation in hemodialysis patients decreases markedly, and this pathological condition is improved by hemodialysis.