RESUMEN
The in vitro effect of dexamethasone on the clonal growth of haematopoietic progenitors in preterm infants was investigated. Concentrations of 10(6)M to 10(9)M were associated with a dose dependent inhibition of colony formation, with the most clinically important effects seen on the earliest erythroid and granulocyte-macrophage colonies. Because of the potential clinical implications of these observations, studies are needed to determine the effects of dexamethasone on haematopoiesis in preterm infants.
Asunto(s)
Dexametasona/análogos & derivados , Glucocorticoides/farmacología , Células Madre Hematopoyéticas/efectos de los fármacos , Recien Nacido Prematuro/sangre , Adulto , Técnicas de Cultivo de Célula , Ensayo de Unidades Formadoras de Colonias , Dexametasona/farmacología , Relación Dosis-Respuesta a Droga , Células Precursoras Eritroides/efectos de los fármacos , Eritropoyetina/farmacología , Sangre Fetal/citología , Sangre Fetal/efectos de los fármacos , Humanos , Recién NacidoRESUMEN
BACKGROUND: Clinical trials of erythropoietin (EPO) administration to preterm infants have not focused on infants weighing 750 gm or less, the population most likely to receive multiple transfusions because of large phlebotomy losses. It is unknown whether preterm infants weighing 750 gm or less will respond to EPO by accelerating erythropoiesis, or whether EPO administered to this population will decrease blood transfusions. METHODS: We randomly assigned 28 extremely low birth weight preterm infants (mean +/- SEM: 24.7 +/- 0.3 weeks' gestation, 662 +/- 14 gm birth weight), in the first 72 hours of life, to receive either EPO (200 U/kg/day) or placebo for 14 days and administered transfusions only according to protocol over a 21-day study period. All infants received 1 mg/kg/day iron dextran in their total parenteral nutrition solution during the 14-day treatment period. RESULTS: During the 21-day study period, a lower number and volume of transfusions were received by the EPO recipients (4.7 +/- 0.7 transfusions per patient and 70 +/- 11 ml/kg per patient) than by the placebo recipients (7.5 +/- 1.1 transfusions per patient and 112 +/- 17 ml/kg per patient; p < 0.05, EPO vs placebo), whereas hematocrits remained similar in the two groups. Reticulocyte counts were similar in both groups on day 1 but were greater in the EPO recipients on day 14 (EPO day 1, 351 +/- 53; EPO day 14, 359 +/- 40 x 10(3)/microl; placebo day 1, 334 +/- 64; placebo day 14, 120 +/- 10 x 10(3)/microl; p < 0.01, EPO vs placebo). Serum ferritin concentrations were similar in both groups at the beginning of the study but were greater in the placebo recipients by day 14 (EPO, 262 +/- 44 microg/L; placebo, 593 +/- 92 microg/L; p < 0.01). No adverse effects of EPO or iron were noted. CONCLUSION: The combination of EPO and parenteral iron stimulates erythropoiesis in preterm infants weighing 750 gm or less and results in fewer transfusions during their first 3 weeks of life.
Asunto(s)
Anemia Hemolítica/terapia , Transfusión Sanguínea , Eritropoyetina/uso terapéutico , Enfermedades del Prematuro/terapia , Recién Nacido de muy Bajo Peso , Hierro/uso terapéutico , Anemia Hemolítica/sangre , Terapia Combinada , Método Doble Ciego , Ferritinas/sangre , Edad Gestacional , Hematócrito/métodos , Humanos , Recién Nacido , Enfermedades del Prematuro/sangre , Nutrición Parenteral Total , Proteínas Recombinantes , Recuento de ReticulocitosRESUMEN
Erythropoietin (Epo) was measured by enzyme-linked immunosorbent assay in 80 cerebrospinal fluid (CSF) samples to determine whether Epo is present in the CSF of infants, CSF Epo concentrations correlate with age, and CSF Epo concentrations correlate with Epo therapy. Epo was present in the CSF of normal neonates. CSF Epo concentrations correlated negatively with increasing age. Recombinant Epo therapy did not affect CSF Epo concentrations, although values ranged somewhat higher in this group.
Asunto(s)
Eritropoyetina/líquido cefalorraquídeo , Recién Nacido/líquido cefalorraquídeo , Recien Nacido Prematuro/líquido cefalorraquídeo , Adolescente , Adulto , Envejecimiento/líquido cefalorraquídeo , Niño , Preescolar , Ensayo de Inmunoadsorción Enzimática , Eritropoyetina/uso terapéutico , Edad Gestacional , Humanos , Lactante , Persona de Mediana Edad , Proteínas Recombinantes/uso terapéuticoRESUMEN
UNLABELLED: OBJECTIVE/STUDY DESIGN: After blood loss, production of erythropoietin in adults increases, which accelerates erythropoiesis and restores the erythroid mass. It is unclear whether preterm infants with large phlebotomy losses have a similar response. We therefore measured serum erythropoietin concentrations in 11 ill preterm infants (1057 +/- 167 gm) as their phlebotomy losses accumulated. RESULTS: Before the first transfusion, erythropoietin concentrations were 68.9 +/- 36.2 mU/ml (range 0 to 205 mU/ml) at 5 ml/kg blood out, 17.4 +/- 8.9 mU/ml at 10 ml/kg, and 4.8 +/- 2.6 mU/ml at 15 ml/kg. Erythropoietin concentrations did not increase in any patients despite increasing phlebotomy losses. CONCLUSION: Serum erythropoietin concentrations in ill preterm infants do not increase in the face of significant blood loss. Although the mechanistic explanation for this failure is unclear, it likely contributes to the transfusion requirements of this population.