EFFECT OF RECOMBINANT-HUMAN-ERYTHROPOIETIN TREATMENT ON CIRCULATING RETICULATED PLATELETS IN UREMIC PATIENTS - ASSOCIATION WITH EARLY IMPROVEMENT IN PLATELET-FUNCTION

Recombinant human erythropoietin improves platelet function in uremia through the correction of anemia, but this effect can be seen also bef ore the hematocrit rise. We studied 12 hemodialyzed patients (seven me n, 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 aggregatio n induced by adenosine 5'-diphosphate (ADP), epinephrine, collagen, ar achidonic acid, and ristocetin, and reticulated platelets determined b y flow cytometry after staining with thiazole orange were measured. Pl atelet aggregation induced by all the agonists were impaired in uremic patients (P < 0.01), but ADP and ristocetin-induced aggregations impr oved after treatment (P < 0.01), Hemodialyzed patients had less reticu lated platelets than controls (P < 0.01). Reticulated platelets increa sed after three doses of treatment (P < 0.01), In conclusion, improvem ent of platelet function at early stages of recombinant human erythrop oietin treatment may be attributed to the increase in young platelets detected as reticulated platelets. Am. J, Hematol, 59:105-109, 1998, ( C) 1998 Wiley-Liss, Inc.