Endothelin Concentrations in Preterm Infants Treated with Human Recombinant Erythropoietin

Abstract

Background: Increased endothelin-1 (ET-1) production following recombinant erythropoietin (Epo) administration is a presumed etiology for the hypertension reported in some adults. It is unknown whether Epo has similar effects in preterm infants. Methods: Serum ET-1 and Epo concentrations were measured prior to study, and following the second and third doses in 20 preterm infants receiving intravenous (IV) or subcutaneous (SC) Epo. Blood pressures were monitored prior to Epo administration and during the first, second, and third dose. Results: Infants (963 ± 54 g birth weight, 27.4 ± 0.6 weeks gestational age, 18 ± 3 days of life; mean ± SEM) had baseline Epo concentrations of 5.5 ± 1.3 mU/ml and ET-1 concentrations below the lower limits of detection (<1 pg/ml). Epo concentrations were 1,848 ± 274 and 1,672 ± 295 mU/ml following the second and third IV dose, respectively, while Epo concentrations were 420 ± 92 and 290 ± 35 mU/ml after the second and third SC dose, respectively (p < 0.005, SC versus IV). ET-1 concentrations remained below the limits of detection in all but 6 infants, whose concentrations were <3.3 pg/ml. Blood pressures did not increase above baseline in either group during the study period. Conclusion: Despite the wide range of Epo concentrations measured, no correlation was observed between Epo concentrations, ET-1 concentrations, and blood pressure during the 1-week study period. The long-term effects of Epo on ET-1 concentrations and blood pressure in preterm infants require further study.