Oxidative stress and haemodialysis: role of inflammation and duration of dialysis treatment

Background. Oxidative stress has long been demonstrated in haemodialysis pa tients. However, the factors influencing their oxidative status have not be en characterized extensively in these patients. Therefore, the present stud y was designed to investigate the influence of a large number of factors kn own to be associated with oxidative stress. Methods. In the present cross-sectional study, we determined the plasma lev els of lipid and protein oxidation markers in 31 non-smoking haemodialysis patients and 18 non-smoking healthy subjects, together with various compone nts of the antioxidant system at the plasma and erythrocyte level. Results, No influence of age, diabetes or iron overload on oxidative marker s and plasma and erythrocyte antioxidant systems was detected in these haem odialysis patients. The lack of an association between iron overload and ox idative status map be related to the lower level of plasma ascorbate in hae modialysis patients, since ascorbate favours the generation of free iron fr om ferritin-bound iron. Interestingly, plasma C reactive protein (CRP) leve ls measured by highly sensitive CRP assay were correlated positively with p lasma levels of thiobarbituric acid reactive substances (r = 0.38, P < 0.04 ) and negatively with plasma <alpha>-tocophorol levels (r = -0.36, P < 0.01 ). Moreover, significant inverse correlations were observed between duratio n of dialysis treatment and plasma levels of <alpha>-tocopherol (r = -0.49, P < 0.02) and ubiquinol (r = -0.40, P < 0.05). Conclusions. Our results suggest that inflammatory status and duration of d ialysis treatment are the most important factors relating to oxidative stre ss in haemodialysis patients.