Plasma Immunoreactive Endothelin Levels Are Increased in Hemodialysis Patients with Hypertension Following Erythropoietin Therapy.

To elucidate the mechanism responsible for the hypertension following recombinant human erythropoietin (rhEpo) therapy in hemodialysis patients, we determined plasma immunoreactive (ir-) endothelin-1 (ET-1) in Epo-induced hypertension. Sixteen hemodialysis patients (54±3 years) were studied. RhEpo was administered (30-120IU/kg/week) for 12 weeks. Blood pressure, hematocrit (Ht), plasma ir-ET-1, renin, aldosterone, norepinephrine, epinephrine, and atrial natriuretic peptide (ANP) were determined. Ht increased significantly in all patients. Based upon the changes in mean blood pressure (MBP) after rhEpo therapy, patients were classified into two groups: hypertensive (n=9) with ΔMBP >10mmHg, and normotensive (n=7) with ΔMBP≤10mmHg. Plasma ir-ET-1 in the hypertensive group increased significantly from 0.52±0.08pmol/liter to 0.88±0.08pmol/liter, while that in the normotensive group did not change. There was a positive correlation between changes in plasma ir-ET-1 and MBP in the hypertensive group. After cessation of rhEpo therapy, the decrease in plasma ir-ET-1 level paralleled the decreases in Ht and MBP. There were no significant changes in plasma renin, aldosterone, norepinephrine, epinephrine, and ANP between the two groups after rhEpo therapy. These results suggest that ET-1 participates to some extent in the pathogenesis of hypertension following rhEpo therapy. (Hypertens Res 1992; 15: 11-16)