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Abstract

Recombinant human erythropoietin improves platelet function in uremia through the correction of anemia, but this effect can be seen also before the hematocrit rise. We studied 12 hemodialyzed patients (seven men, five women) who received recombinant human erythropoietin (40 IU kg −1 i.v., three times weekly) and were evaluated before treatment and after three doses; 24 control subjects were used. Platelet aggregation induced by adenosine 5-diphosphate (ADP), epinephrine, collagen, arachidonic acid, and ristocetin, and reticulated platelets determined by flow cytometry after staining with thiazole orange were measured. Platelet aggregation induced by all the agonists were impaired in uremic patients (P < 0.01), but ADP and ristocetin-induced aggregations improved after treatment (P < 0.01). Hemodialyzed patients had less reticulated platelets than controls (P < 0.01). Reticulated platelets increased after three doses of treatment (P < 0.01). In conclusion, improvement of platelet function at early stages of recombinant human erythropoietin treatment may be attributed to the increase in young platelets detected as reticulated platelets. Am.