Human erythrocyte δ-aminolevulinate dehydratase activity and oxidative stress in hemodialysis patients

Background:Oxidative stress is a complicating factor in chronic renal failure, especially in hemodialysis (HD) patients. Also, aluminum intoxication may occur during hemodialysis treatment. Aluminum has been shown to inhibit the sulfhydryl-containing enzyme δ-aminolevulinate dehydratase (ALA-D). Thus, the involvement of –SH oxidation in ALA-D inhibition and its relationship with serum Al levels and lipid peroxidation in HD patients were evaluated.Methods:Blood ALA-D activity, plasma thiobarbituric acid reactive substances (TBARS), and serum aluminum levels were measured in HD patients (n = 37) and healthy controls (n = 20).Results:TBARS and Al levels were higher in HD patients than in controls (p < 0.01), while ALA-D activity was lower (p < 0.05). The sulfhydryl-reducing agent dithiothreitol (DTT) reactivated ALA-D of HD patients, but activity was still lower than that of controls. ALA-D activity was negatively correlated with TBARS (r = − 0.63, p < 0.01) and aluminum levels (r = − 0.31, p < 0.05).Conclusions:Reduced ALA-D activity in HD patients was found to be related to the oxidation of –SH groups essential for enzyme activity. Our results suggest that increased oxidative stress may have contributed to enzyme inhibition in HD patients.