Erythropoietin's brain injury correlations diverge by treatment; transfusions heighten ROP risk in preterm infants.
Background
Extremely preterm infants face significant risks, including retinopathy of prematurity (ROP) and brain injury, which can lead to long-term neurodevelopmental impairments. Erythropoietin (Epo) is a hormone known for its role in red blood cell production, but also recognized for its potential neuroprotective properties and as a biomarker for hypoxic stress. Despite its therapeutic promise, the precise relationship between endogenous Epo levels, recombinant human Epo (rHuEpo) treatment, and clinical outcomes like ROP and brain injury in this vulnerable population remains complex and warrants deeper investigation to optimize care strategies.
Study Design
This was a post hoc analysis of the Preterm Erythropoietin Neuroprotection Trial (PENUT), involving 941 extremely preterm infants born between 24 0/7 and 27 6/7 weeks gestation. Infants were originally randomized to receive either recombinant human erythropoietin (rHuEpo) or placebo. Serum Epo concentrations were measured at baseline (within 24 hours), and again at 7, 9, and 14 days of life. Brain injury was assessed via magnetic resonance imaging (MRI) at 36 weeks postmenstrual age in a subset of 220 infants. The study explored correlations between endogenous Epo, rHuEpo treatment, red blood cell transfusions, and outcomes including ROP and brain injury.
Results
Baseline endogenous Epo concentrations negatively correlated with gestational age, delayed cord clamping, and Apgar scores, while positively correlating with intraventricular hemorrhage and risk of death. Neither baseline endogenous Epo nor its trajectories from birth to 14 days were associated with ROP. In the placebo group, Epo at 1 week of life (r=0.26, p=0.033) and 2-week area under the curve (r=0.28, p=0.019) positively correlated with white matter injury. Conversely, in the treatment group, Epo at 14 days negatively correlated with white matter injury (r=-0.35, p=0.004). Grey matter injury showed a negative correlation with baseline Epo in the placebo group (r=-0.27, p=0.01) but a positive correlation in the treatment group (r=0.23, p=0.047).
Key Findings
- Baseline endogenous Epo negatively correlated with gestational age and Apgar scores, but positively with intraventricular hemorrhage and death risk.
- Endogenous Epo levels were not associated with retinopathy of prematurity (ROP) outcomes.
- In the placebo group, Epo at 1 week positively correlated with white matter injury (r=0.26, p=0.033).
- In the rHuEpo treatment group, Epo at 14 days negatively correlated with white matter injury (r=-0.35, p=0.004).
- Red blood cell transfusions were significantly associated with severe ROP (p<0.0001) and total brain injury (p=0.007).
Why It Matters
This analysis highlights the dual nature of erythropoietin as both a potential therapeutic agent and a critical biomarker of stress in extremely preterm infants. The divergent correlations between Epo levels and brain injury outcomes, depending on whether infants received rHuEpo treatment or placebo, suggest that exogenous Epo may modulate the endogenous Epo response and its downstream effects differently. This implies that simply measuring endogenous Epo might not fully capture its complex role when rHuEpo is administered. Furthermore, the strong association between red blood cell transfusions and severe ROP, particularly in males, underscores the need for careful consideration of transfusion thresholds and practices in this vulnerable population, potentially influencing future clinical guidelines for neonatal care protocols to mitigate ROP risk.
erythropoietin
preterm-infants
retinopathy-of-prematurity
brain-injury
neuroprotection
post-hoc-analysis