Does erythropoietin protect the preterm brain?

Pharmacological neuroprotection and clinical trials of novel therapies for neonatal peri-intraventricular hemorrhage: a comprehensive review

Peri-intraventricular hemorrhage (PIVH) is a serious condition for preterm infants, caused by traumatic or spontaneous rupture of the germinal matrix (GM) capillary network in the cerebral ventricles. It is a common source of morbidity and mortality in neonates, and risk correlates with earlier delivery, low birth weight, maternal-fetal infection, and vital sign derangements, among others. PIVH typically occurs in the first 72 h of life, and symptoms, when present, manifest most commonly within the first week of life. Prevention remains the primary goal in management, predominantly via prolonging of gestation. Current therapy protocols are center-dependent without consistent consensus guidelines, but infant positioning, homeostatic stabilization, and neuroprotection offer potential options. In this update of pharmacologic neuroprotective therapies for PIVH, we highlight commonly utilized therapies and review the investigative literature. Further multi-institutional clinical trials and basic research studies are required.

Single dose recombinant erythropoietin versus moderate hypothermia for neonatal hypoxic ischemic encephalopathy in low resource settings

OBJECTIVE

To determine the safety and efficacy of single dose systemic recombinant human erythropoietin (rEPO) in neonates with perinatal hypoxic Ischemic Encephalopathy (HIE), and its effect on serum brain-derived neurotrophic factor (BDNF) and neuron-specific enolase (NSE).

METHODS

Forty-five full-term neonates; 30 with perinatal HIE and 15 controls were studied. HIE neonates were randomized into three intervention groups (first 6 h of life): 10 received single subcutaneous 1500 U/kg rEPO at day-1, 10 subjected to hypothermia for 72 h and 10 received supportive care. BDNF and NSE measured during first 6 h and day 5 postnatal. Daily Thompson's score, MRI brain and neuromuscular function scale for survivors at 3 months of age were done.

RESULTS

Hypothermia group had best survival especially with stage-II Sarnat scale, followed by rEpo and supportive group. BDNF day-5 was significantly higher in each group compared to controls. MRI score and neuromuscular function score were non-significantly lower in the hypothermia group compared to rEPO.

CONCLUSIONS

Therapeutic hypothermia was superior to single dose rEpo for neuro-protection in HIE especially in patients with stage-II Sarnat scale. Therapeutic effect of combined rEPO multiple dosing and modest hypothermia therapy should be studied.

Higher cumulative doses of erythropoietin and developmental outcomes in preterm infants

OBJECTIVE

We hypothesized that higher cumulative doses of recombinant erythropoietin (rEPO) for extremely preterm infants during the first 6 postnatal weeks would improve developmental outcomes, as evidenced in evaluations with the Bayley Scales of Infant Development-II Revised.

METHODS

This was a retrospective cohort study with a data set for a group (N = 366) of infants of <1500 g and < or =30 weeks of gestation that was created initially to examine the association between rEPO treatment and retinopathy of prematurity. Infants who underwent developmental follow-up evaluations at corrected age of >12 months were included. The associations between rEPO doses and higher Bayley Scales of Infant Development Psychomotor Developmental Index and Mental Developmental Index (MDI) scores were estimated in multivariate linear regression analyses.

RESULTS

Eighty-two infants underwent developmental evaluations after 12 months. The median age of evaluation was 25 months. The median 6-week cumulative rEPO dose was 3750 U/kg. In multivariate analyses, Psychomotor Developmental Index (PDI) scores were associated with transfusions, female gender, birth weight, and 5-minute Apgar scores (R(2) = 0.39). MDI scores were associated with 6-week rEPO dose, female gender, prenatal steroid treatment for > or =48 hours, and breast milk feedings (R(2) = 0.40).

CONCLUSIONS

These findings identify a dose-response relationship between rEPO treatment and improved MDI scores. They are consistent with findings of adult studies and animal brain injury models and await confirmation.

Attenuation of monocyte proinflammatory cytokine responses to Neisseria meningitidis in children by erythropoietin

Meningococcal disease is a leading infectious cause of death in children in industrialized countries. The induction of high levels of proinflammatory cytokines has been implicated in the pathogenesis of Neisseria meningitidis-related multi-organ failure. Here, we demonstrate that N. meningitidis serotypes A and B induce significantly higher levels of tumour necrosis factor (TNF)-alpha positive cells in vitro in infants and young children compared with adults (serotype A/B; infants: 64.9%/63.9%; children: 77.8%/64.3% versus adults: 27.7%/32%; P < 0.005). Serotype A induces also higher levels of interleukin (IL)-6 positive cells in neonates and infants compared with adults (serotype A; newborn 55.4%; infants 58.8% versus adults 49%; P < 0.05). Treatment with human recombinant erythropoietin in vitro resulted in significant attenuation of the N. meningitidis-induced proinflammatory response in all age groups (reduction rate of erythropoietin for IL-6 after stimulation with serotype B: newborn 28%, infants 15%, children 23% and adults 28% and for TNF-alpha after stimulation with serotype B: newborn 27%, infants 22%, children 20% and adults 28%; P < 0.05). We conclude that (i) Neisseria meningitidis induces a higher TNF-alpha response in infants and children compared with adults and (ii) erythropoietin was able to attenuate IL-6 and TNF-alpha production in all investigated age groups. These data may explain the high incidence of meningococcal infection in infants and makes erythropoietin a potentially attractive candidate for interventional strategies in an otherwise devastating course of the disease.

Is there a role for erythropoietin in neonatal medicine?

Since it was first cloned in 1985, the therapeutic potential of recombinant human erythropoietin in the neonatal hyporegenerative anaemias has been studied-the anaemia of prematurity and haemolytic disease of the newborn. Between 60% and 100% of preterm infants are transfused before three weeks of age, a large proportion receiving more than one transfusion. Blood transfusions are currently also the mainstay of treatment for the hyporegenerative anaemia encountered in neonates with Rhesus disease. Sometimes the situation is complicated by the religious beliefs of the parents. Blood transfusions are associated with numerous risks, from transmission of infection to local injury, and in an effort to minimize these risks Neonatologists have looked to recombinant erythropoietin. Despite an extensive number of studies, there is as yet no clear consensus as to whether the use of recombinant erythropoietin in Neonatal medicine minimizes the need for blood transfusions without risk to the neonate. In this article we review the evidence for and against the use of recombinant erythropoietin in Neonatal medicine.

Stepping up versus standard doses of erythropoietin in preterm infants: a randomized controlled trial

In this study, it is hypothesized that a planned increase in the dose of recombinant human erythropoietin (rh-EPO) can prevent transfusion in very low birth weight infants. Two different regimens of rh-EPO were administrated, one consisting in increasing dosage up to 5000 U/kg/wk, according to the individual reticulocytes response, and the second in a standard therapy of 1250 U/kg/wk. Fifty-one infants participated. Despite a significant higher reticulocytosis, the study was prematurely terminated due to the results of an interim analysis showing that transfusion was not avoided by increasing the rh-EPO. No significant differences were found between the two regimens concerning transfusion rate, volume transfused, gain in weight, and adverse effects. Progressive titration of rh-EPO to improve the biological response does not leave premature infants free of transfusion.

The insulin-like growth factor system and its pleiotropic functions in brain

In recent years, much interest has been devoted to defining the role of the IGF system in the nervous system. The ubiquitous IGFs, their cell membrane receptors, and their carrier binding proteins, the IGFBPs, are expressed early in the development of the nervous system and are therefore considered to play a key role in these processes. In vitro studies have demonstrated that the IGF system promotes differentiation and proliferation and sustains survival, preventing apoptosis of neuronal and brain derived cells. Furthermore, studies of transgenic mice overexpressing components of the IGF system or mice with disruptions of the same genes have clearly shown that the IGF system plays a key role in vivo.

Growth rate of corpus callosum in very premature infants

BACKGROUND AND PURPOSE

It is desirable to develop a bedside method for assessing cerebral development in the very premature infant to monitor the effectiveness of interventions aimed at improving cerebral development. Our aim was to describe the growth trajectory of the corpus callosum (CC) on cranial sonography in very premature infants.

METHODS

We recruited 100 very-low-birth-weight infants admitted to a single regional level III neonatal intensive care unit from November 1998 to November 2000. Cranial sonography images of the CC were obtained for 64 (32 boys) infants (mean gestational age, 28 weeks; range, 23-33 weeks) in the first week of life and at term equivalency. The growth rate of the CC was compared in the 64 study infants to the expected growth rate of 0.20-0.27 mm/day from antenatal data and correlated with clinical outcome at 2 years of age by using Mental Development Index (MDI) and Psychomotor Development Index (PDI).

RESULTS

The average growth rate of the CC was half of that expected from antenatal data. Mean growth rates were similar for all gestational ages (mean, 0.11 mm/day; range, 0.05-0.29; P = .4). The CC at term equivalency was longer for those in MDI class 2 (mean, 44.3 mm) compared with MDI class 3 (mean 40.2 mm; P = .003) as well as for PDI class 2 versus 3 (P = .017).

CONCLUSION

Measurement of the length of the CC at cranial sonography is reproducible. Those with poorer neurodevelopmental outcomes have a shorter CC at term equivalency. The CC grows at a much lower rate postnatally than in utero among very premature infants.