Effect of recombinant human erythropoietin administration on peripheral blood neutrophil counts of premature infants

Effect of enteral erythropoietin on feeding-related complications in preterm newborns: A pilot randomized controlled study

BACKGROUND AND STUDY AIMS

To evaluate the effects of enteral administration of recombinant human erythropoietin (rhEPO) on feeding-related complications in preterm infants.

PATIENTS AND METHODS

This double-blind, randomized controlled pilot study enrolled 120 preterm infants born ≤ 32 weeks' gestation who were admitted to the neonatal intensive care unit in a tertiary hospital; 60 patients randomly received recombinant human erythropoietin while the other 60 received placebo. Newborns who underwent cardiopulmonary resuscitation, infants with genetic syndromes, infants with inborn errors of metabolism, infants with major congenital or acquired gastrointestinal tract malformations, infants with previous use of parenteral growth factors such as recombinant human erythropoietin and granulocyte-macrophage colony-stimuating factor (GM-CSF) and infants previously treated with intravenous immunoglobulin were excluded. Overall, 48 patients withdrew from the study because of intravenous haematopoietic growth factor intake or death before treatment was completed. A total of 72 preterm infants remained in the study: 36 preterm infants in the erythropoietin (EPO) group, and 36 preterm infants in the placebo group. The day that enteral feeding was successfully started, the time to establishing one-half, two-thirds, and full enteral feedings (reaching at least 150 mL/kg/day), the number of episodes of feeding intolerance, the time to regain birth weight and the incidence of necrotizing enterocolitis (NEC) were recorded.

RESULTS

Both groups showed no significant difference in the time to achieve one-half, two-thirds, or full enteral feeding, no signs of feeding intolerance, and no cases of NEC were recorded.

CONCLUSION

Enteral erythropoietin does not appear to affect feeding intolerance or NEC incidence.

The role of recombinant Human erythropoietin in neonatal anemia

AIM

To estimate the blood level of Erythropoietin(EPO) in neonates with anemia of prematurity (APO) and in late hypo-regenerative anemia and to clarify role of EPO in correction of anemia and reducing the number of blood transfusions.

METHODS

This study was carried out on 60 neonates divided into; group I (30 preterm neonates) with AOP received EPO (250 IU/kg/dose subcutaneously 3 times weekly for 4 weeks), compared to group II (30 neonates) with AOP treated only with blood transfusion. CBC parameters and transfusion requirements were followed during therapy. Serum level of EPO was measured by ELISA technique.

RESULTS

By the end of the 4th week of therapy, there was significant increase in group I post r-Hu EPO compared to group II regarding reticulocyte counts (P < 0.001) leading to rise of the Hb (P < 0.001), Hct levels (P < 0.001) with subsequent reduction in the overall number of blood transfusions (P < 0.001).

CONCLUSION

EPO therapy in conjunction with iron, vitamin E and folic acid, stimulated erythropoiesis and significantly reduced the need for blood transfusion in AOP.

Late-onset neutropenia: defining limits of neutrophil count in very low birth weight infants

OBJECTIVE

To evaluate the incidence, onset, duration, characteristics and importance of late-onset neutropenia (defined as absolute neutrophil count<1500 μl(-1) at 3 weeks of age or later) in a group of very low birth weight (VLBW) infants.

STUDY DESIGN

Routine complete blood cell counts (CBCs) obtained from VLBW infants over a period of 7 years were gathered retrospectively, including those of newborns with weekly CBCs taken over a duration of at least 3 weeks. Data were obtained from between January 2003 and December 2009.

RESULT

CBCs of 399 newborns were included. Values were obtained from birth to 36 weeks of postnatal age. Late-onset neutropenia was observed in 259 cases (65%). Neutropenic infants had a mean of 0.5 weeks lower gestational age. Late-onset neutropenia was more frequent in children with intraventricular hemorrhage but not in patients who received erythropoietin. The median age of neutropenia onset was 7 weeks in extremely low birth weight infants and 6 weeks in VLBW infants. The fifth percentile of neutrophils between weeks 3 and 4 was 1280 μl(-1) and between weeks 13 and 15 was 500 μl(-1). The average duration was 2 weeks with normalized values after 18 weeks.

CONCLUSION

A neutrophil count <1500 μl(-1) after the third week of life is frequently observed in VLBW infants and should not be used as a lower reference limit. The fifth percentile varies according to postnatal age from around 1300 μl(-1) in week 4 of life, decreasing to a nadir of 500 μl(-1) between 3 and 4 months of age. Values normalize in the first year of life.

The effect of erythropoietin on normal and neoplastic cells

Erythropoietin (Epo) is an essential hormone that binds and activates the Epo receptor (EpoR) resident on the surface of erythroid progenitor cells, thereby promoting erythropoiesis. Recombinant human erythropoietin has been used successfully for over 20 years to treat anemia in millions of patients. In addition to erythropoiesis, Epo has also been reported to have other effects, such as tissue protection and promotion of tumor cell growth or survival. This became of significant concern in 2003, when some clinical trials in cancer patients reported increased tumor progression and worse survival outcomes in patients treated with erythropoiesis-stimulating agents (ESAs). One of the potential mechanisms proffered to explain the observed safety issues was that functional EpoR was expressed in tumors and/or endothelial cells, and that ESAs directly stimulated tumor growth and/or antagonized tumor ablative therapies. Since then, numerous groups have performed further research evaluating this potential mechanism with conflicting data and conclusions. Here, we review the biology of endogenous Epo and EpoR expression and function in erythropoiesis, and evaluate the evidence pertaining to the expression of EpoR on normal nonhematopoietic and tumor cells.

Late-onset neutropenia in very low birthweight infants

AIM

To evaluate the incidence and duration of late-onset neutropenia (defined as an absolute neutrophil count (ANC) <1500 mm(-3) at a postnatal age of >3 wk) in a population of infants with birthweight <2000 g, and to determine whether copper deficiency, a possible cause of both anemia and neutropenia, may be associated with this complication.

METHODS

Complete blood cell count and differential were assessed in 247 low (LBW) and very low birthweight (VLBW) infants who were discharged after 3 wk of life. In neutropenic infants plasma copper and ceruloplasmin levels were also measured.

RESULTS

Late-onset neutropenia was detected in 11 out of 147 VLBW infants (7.5%) and in 7 out of 127 LBW infants (5.5%). A neutrophil count of <1000 mm(-3) was observed in 14 infants (5.1%). A significantly lower gestational age was found in neutropenic infants compared with non-neutropenic infants. In neutropenic infants ANCs were significantly correlated with hemoglobin and hematocrit. In addition, a significant negative correlation was found between neutrophil and reticulocyte counts. Plasma copper concentration was significantly correlated with birthweight. Oral copper sulfate was administered to infants with plasma copper concentration <50 microg dl(-1), and did not seem to affect ANC, hemoglobin, hematocrit or reticulocyte counts.

CONCLUSION

Late-onset neutropenia appears to be a benign condition that is not associated with any particular complication and does not require specific treatment. Reference ranges after the early neonatal period and during the first few months of life in LBW and VLBW infants should probably be set at lower values.

Early treatment with erythropoietin beta ameliorates anemia and reduces transfusion requirements in infants with birth weights below 1000 g

OBJECTIVE

To investigate whether recombinant erythropoietin (rhEPO) reduces the need for transfusion in extremely low birth weight (ELBW) infants (birth weight 500-999 g) and to determine the optimal time for treatment.

METHODS

In a blinded multicenter trial, 219 ELBW infants were randomized on day 3 to one of 3 groups: early rhEPO group (rhEPO from the first week for 9 weeks, n = 74), late rhEPO group (rhEPO from the fourth week for 6 weeks, n = 74), or control group (no rhEPO, n = 71). All infants received enteral iron (3-9 mg/kg/day) from the first week. The rhEPO beta dose was 750 IU/kg/week. Success was defined as no transfusion and hematocrit levels never below 30%.

RESULTS

Success rate was 13% in the early rhEPO group, 11% in the late rhEPO group, and 4% in the control group (P =.026 for early rhEPO versus control group). Median transfusion volume was 0.4 versus 0.5 versus 0.7 mL/kg/day (P =.02) and median donor exposure was 1.0 versus 1.0 versus 2.0 (P =.05) in the early rhEPO group, the late rhEPO group, and the control group, respectively. Infection risk was not increased and weight gain was not delayed with rhEPO beta.

CONCLUSION

Early rhEPO beta treatment effectively reduces the need for transfusion in ELBW infants.

Effect of recombinant human erythropoietin in preterm infants

Twenty-five premature infants (mean gestational age+/-SD, 31.4+/-1.9 weeks) were administered subcutaneously recombinant human erythropoietin (rHuEpo) at a dose of 300 u/kg of body weight three times a week beginning on the third day of life and continuing for 6 weeks. The controls (n=23) were premature infants with a mean gestational age of 32.2+/-2.3 weeks who did not receive rHuEpo. Haematological indices, haemoglobin and serum phosphate (Pi), and red blood cell (RBC) phosphate metabolites (ATP, 2,3-DPG, RBCPi) were tested monthly until the 6th month and thereafter at the 9th and 12th months of life. The level of serum soluble transferrin receptors (sTfR) correlated significantly with rHuEpo (p<0.05). The ratio of sTfR to log (ferritin) was significantly higher (p<0.001) in the infants treated with rHuEpo than the controls. Intracellular organic and inorganic Pi changes were not affected by the Epo administration. The RBC 2,3-DPG seemed adequate in infants receiving rHuEpo.

Preventive effect of different dosage of recombinant human erythropoietin on anemia of premature infants

To assess the efficacy and the optimum dose of recombinant human erythropoietin (rhEpo) on the anemia of premature, 45 preterm infants with a gestational age of less than 35 weeks and birth weight of less 1,800 g were randomly assigned to treatment group 1 (n = 15, receiving subcutaneous rhEpo 150 U/kg.time), treatment group 2 (n = 15, receiving 250 U/kg.time), three times a week for 6 weeks, and control group (n = 15, no treatment was given). All preterm infants received supplements of vitamin E (20 IU) and iron (20 mg) each day. Our results showed that postnatal decline of hemoglobin (Hb) and hematocrit (Hct) were lessened in the treatment groups, particularly in the group 2 and the differences were very significant (P < 0.0001 for all). Treated infants had significantly higher reticulocyte counts (Ret) (P < 0.0001 for all), but there was no significant difference between the two treatment groups (P > 0.05). Serum iron dropped significantly in the treatment groups as compared with control group (P < 0.01 for all), but no dose-dependent relationship was observed in treated infants (P > 0.05). After treatment, serum levels of erythropoietin was higher in group 2 than those in group 1 and control group (P < 0.0001, P < 0.01 and P < 0.05, respectively). There was no significant difference between group 1 and control group (P > 0.05). No side effects related to rhEpo therapy were observed. Our study suggested that rhEpo therapy stimulates endogenous erythropoiesis and enhances Ret, Hct and level of Hb in a dose-dependent manner in premature infants. The therapy is more efficient when given in higher dosages.

The effect of recombinant human erythropoietin on circulating hematopoietic progenitor cells in anemic premature infants

In vitro and animal studies suggest that high concentrations of recombinant human erythropoietin (rHuEPO) might divert multipotent progenitors into erythroid maturation at the expense of granulocyte production. We determined whether changes of number and lineage commitment of peripheral blood progenitor cells occur in premature infants during therapy with rHuEPO. Thirty preterm infants were randomly assigned either to receive 300 IU of eopoetin alpha s.c. per kilogram body weight three times a week for four weeks or to a control group. At study entry and after two weeks of treatment the numbers of circulating BFU-E, granulocyte-macrophage colony-forming units (CFU-GM) and granulocyte-erythrocyte-macrophage-megakaryocyte CFU (CFU-GEMM) were analyzed by semisolid culture technique, CD34+ cells and early myeloid CD34+CD45RA- progenitors by flow cytometry. As compared with the control group, rHuEPO treatment did not exert any significant modulatory effect on numbers of CFU-GM, nor was there a significant change in numbers of BFU-E, CFU-GEMM, total-CFU, percentage of CD34+ or CD34+CD45RA- cells. Mean neutrophil count was not significantly reduced at any period during the study. Compared with the control group, the infants receiving rHuEPO had higher hematocrit values (p = 0.003) and absolute reticulocyte counts (p < 0.001). The median cumulative volume of blood transfused per kilogram per day was 0.86 ml (first quartile 0.5 ml; third quartile 1.1 ml) in the control group and 0 ml (first quartile 0 ml; third quartile 0.47 ml) in the rHuEPO group (p = 0.038). We conclude using a relatively high dose of rHuEPO in premature infants, no significant in vivo effect on circulating peripheral blood progenitor or neutrophil count could be detected.

The effect of erythropoietin administration on murine bone marrow chimeras

All patients develop anemia after autologous or allogeneic bone marrow transplantation and red blood cell transfusion is almost always required in the post-transplant period. Recently Epo therapy has been employed in the setting of bone marrow transplantation. As bone marrow transplant patients typically suffer from malignancies and are immunocompromised, further immunosuppression should be avoided. Recent reports have suggested that Epo may modulate immune response. We have studied the effects of Epo on immune response in murine bone marrow chimeras. Epo administration resulted in an increase in hematocrit. There was no significant alteration in lymphocyte numbers, although a shift in lymphocytes toward T cell predominance was observed. Epo administration resulted in enhanced cell proliferation in response to T and B cell mitogens, although no alteration in cytotoxicity or natural killer cell activity was observed. No example of Epo-induced impaired immunity was observed.

Use of erythropoietin in premature neonates: controversies and the future

OBJECTIVE

To review and evaluate current research on the use of recombinant human erythropoietin (rhEPO) for the treatment of anemia of prematurity (AOP).

DATA SOURCES

A MEDLINE search (1985-September 1994) was used to identify and retrieve pertinent data about erythropoietin's use in premature neonates. Bibliographies in the relevant literature and International Pharmacy Abstracts were reviewed as well.

STUDY SELECTION

The authors extrapolated data from trials and other literature in which the entire paper or abstract was published. Because of the paucity of data on the use of rhEPO in neonates, all available literature was reviewed and cited, regardless of study methodology.

DATA SYNTHESIS

Most data support that rhEPO is efficacious in treating AOP. Until recently, the published investigations have included only small numbers of patients. Larger, multicenter, placebo-controlled trials suggest that infants weighing less than 1500 g benefit from rhEPO therapy. Questions remain concerning the rhEPO dose and nutrient requirements for optimal efficacy.

CONCLUSIONS

Published clinical trials that have examined the efficacy of rhEPO in the treatment of AOP vary considerably with regard to methodology, rhEPO dose, nutrient doses, and outcome measurement. At present, many questions remain to be answered including ascertaining rhEPO's long-term benefit versus cost/risk as well as its potential contribution to improving the care of the premature neonate.