Interaction between erythropoietin and peripheral polymorphonuclear leukocytes in hemodialysis patients

The effect of erythropoietin (EPO) on the oxidative stress and inflammation caused by polymorphonuclear leukocytes (PMNLs) in chronic hemodialysis (HD ) patients was investigated in vivo and in vitro, The studies were performe d on isolated PMNLs from peripheral blood of healthy controls and HD patien ts before and following 6 weeks of EPO treatment. The oxidative stress was expressed by the rate of superoxide release from phorbol 12-myristate 13-ac etate stimulated PMNLs, and the inflammatory state was evaluated by in vitr o PMNL survival, in addition to white blood cell and PMNL counts of the enr olled subjects, Following 6 weeks of EPO treatment, in HD patients, the rat e of superoxide release from PMN Ls as well as WBC and PMNL counts fell sig nificantly when compared with the pretreatment values. PMNLs from HD patien ts and healthy controls incubated in vitro with increasing amounts of EPO d isplayed a significant reduction in their rates of superoxide release and a significant improvement in survival. We have concluded that EPO interacts with PMNLs, attenuating their primed state in HD patients, thus reducing ox idative stress and the extent of inflammation, To the best of our knowledge , this attenuation of the primed state of PMNLs by EPO is a new finding.