Endogenous erythropoietin concentrations and association with retinopathy of prematurity and brain injury in preterm infants

The role of erythropoietin to prevent red blood cell transfusion in a 2018-2020 two-center cohort of preterm infants

BACKGROUND

Treatment with recombinant human erythropoietin (rHu-EPO) modestly prevented packed red blood cell transfusions (pRBCTs) in preterm infants in studies performed several years ago. In France, some neonatal units stopped using rHu-EPO, while others continued. The aim of this study was to explore the role of rHu-EPO in the prevention of pRBCTs in a recent cohort of preterm infants.

MATERIALS AND METHODS

Preterm infants who met rHu-EPO indications and were hospitalised between 2018 and 2020 in two neonatal units -one that did not use rHu-EPO and another that did- were eligible. Data about the neonatal history, rHu-EPO and iron treatments and pRBCT indications and volumes were collected. Infants exposed and not exposed to rHu-EPO were compared in univariate and multivariate analyses using backward logistic regression and Cox proportional hazards regression.

RESULTS

A total of 257 patients exposed to rHu-EPO and 285 patients who were not exposed were included. Three profiles emerged. In the infants with a gestational age <28 weeks, the cumulative pRBCT volume/kg was similar regardless of rHu-EPO exposure (mean difference -2.8 mL, 95% confidence interval -16.1, 10.5, p=0.68). In the infants born between 28 and 30 weeks, a late pRBCT was prevented in the rHu-EPO group (single pRBCT: no rHu-EPO 22.1% vs rHu-EPO 8%, p=0.003). However, rHu-EPO was not independently associated with avoidance of this pRBCT. Finally, the need for pRBCT was low in the infants born after 30 weeks of gestation, making rHu-EPO treatment futile. In contrast, early iron supplementation was revealed to be critical in preventing pRBCT.

DISCUSSION

No benefit of rHu-EPO in preventing pRBCT was observed in our cohort. The place of rHu-EPO in future requires careful consideration of the population concerned, adjustment of the therapeutic schedule and evolution of the indications for pRBCT.

Early Postnatal Administration of Erythropoietin and Its Association with Neurodevelopmental Outcomes and Incidence of Intraventricular Hemorrhage and Hypoxic-Ischemic Encephalopathy: A Four-Week Observational Study

This study aimed to investigate the impact of early erythropoietin (EPO) administration on the neurodevelopment of newborns, specifically focusing on its effects on hypoxic-ischemic encephalopathy (HIE) and intraventricular hemorrhage (IVH). The primary objective was to determine whether early EPO administration could impact the short-term neurodevelopmental outcomes and provide safety in neonates at risk for neurodevelopmental disorders. Conducted at the "Louis Turcanu" Children's Emergency Clinical Hospital in Timisoara, Romania, this observational study included 121 neonates receiving EPO and 130 No EPO controls. EPO was administered within the first 48 h of life, with doses of 1000 U/kg that escalated to 2000 U/kg if necessary. Besides observing the occurrence of IVH and HIE, this study measured clinical and biochemical markers, including LDH, blood glucose, urea, creatinine, CPK, CRP, PCT, and erythropoietin levels alongside hematology and coagulation profiles. There were no significant differences in baseline characteristics between the groups. The EPO group showed significant reductions in LDH levels from days 1-3 to 7-10 (695.0 U/L to 442.0 U/L) and the APTT value (54.0 s) compared with the No EPO group (38.0 s). Notably, early EPO administration was associated with a significant decrease in HIE severity (beta coefficient: -0.38, p = 0.001). Additionally, lower gestational ages and hemoglobin levels correlated with increased severity of HIE. By week four, there was a significant reduction in moderate and severe HIE cases in the EPO group compared with controls (p = 0.001). Early administration of EPO in neonates significantly reduced the severity of IVH and HIE, suggesting its potential as a neuroprotective agent in neonatal care.

Retinopathy of prematurity protection conferred by uteroplacental insufficiency through erythropoietin signaling in an experimental Murine Model

BACKGROUND

Recent clinical studies suggest that preeclampsia, characterized by uteroplacental insufficiency (UPI) and infant intrauterine growth restriction (IUGR), may be protective against retinopathy of prematurity (ROP) in preterm infants. Experimental models of UPI/IUGR have found an association of erythropoietin (EPO) with less severe oxygen-induced retinopathy (OIR); however, it is unclear if EPO/EPO receptor (EPOR) signaling was involved. We hypothesized that maternal UPI and resultant infant IUGR would protect against features of ROP through EPO/EPOR signaling.

METHODS

We compared transgenic mice with hypoactive EPOR signaling (hWtEPOR) to littermate wild-type mice (mWtEpoR) in a novel combined model of IUGR and ROP. Thromboxane A2 (TXA2) was infused into pregnant C57Bl/6J dams to produce UPI/IUGR; postnatal pups and their foster dams were subjected to a murine OIR model.

RESULTS

Following hyperoxia, hematocrits were similar between littermate wild-type (mWtEpoR) TXA2/OIR and vehicle/OIR pups. mWtEpoR TXA2/OIR had increased serum EPO, retinal EPO and VEGF, and decreased avascular retinal area (AVA) compared to vehicle/OIR pups. In comparison to the mWtEpoR TXA2/OIR pups, AVA was not reduced in hWtEPOR TXA2/OIR pups.

CONCLUSION

Our findings provide biologic evidence that UPI/OIR-induced endogenous EPOR signaling confers protection against hyperoxia-induced vascular damage that may be related to pathophysiology in ROP.

IMPACT

Maternal preeclampsia and infant growth restriction confer retinovascular protection against high oxygen-induced damage through endogenous erythropoietin signaling.

Modifiable Risk Factors and Preventative Strategies for Severe Retinopathy of Prematurity

Severe ROP is characterized by the development of retinal fibrovascular proliferation that may progress to retinal detachment. The purpose of this report is to review five of the most common and well-studied perinatal and neonatal modifiable risk factors for the development of severe ROP. Hyperoxemia, hypoxia, and associated prolonged respiratory support are linked to the development of severe ROP. While there is a well-established association between clinical maternal chorioamnionitis and severe ROP, there is greater variability between histologic chorioamnionitis and severe ROP. Neonatal sepsis, including both bacterial and fungal subtypes, are independent predictors of severe ROP in preterm infants. Although there is limited evidence related to platelet transfusions, the risk of severe ROP increases with the number and volume of red blood cell transfusions. Poor postnatal weight gain within the first six weeks of life is also strongly tied to the development of severe ROP. We also discuss preventative strategies that may reduce the risk of severe ROP. Limited evidence-based studies exist regarding the protective effects of caffeine, human milk, and vitamins A and E.

Reduction of Laser-Induced Choroidal Neovascularization in Mice With Erythropoietin RNA Interference

PURPOSE

The purpose of this study was to evaluate the pathological involvement of erythropoietin (EPO) in experimental choroidal neovascularization (CNV) and its association with neovascular age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV) in the Chinese population.

METHODS

Treatment effect of recombinant EPO protein were assessed by human umbilical vein endothelial cell (HUVEC) proliferation, migration, and tube formation, and ex vivo choroid-sprouting ability. The effect of intravitreal injection of Epo siRNA against neovascularization was evaluated in the laser-induced CNV mouse model. In addition, the association of EPO variants with neovascular AMD and PCV was determined.

RESULTS

Exogenous supplementation of EPO significantly enhanced the migration and tube formation of HUVECs and promoted ex vivo choroid sprouting in mouse retinal pigment epithelium (RPE)-choroid-sclera complex culture. In the experimental CNV mouse model, Epo expression was found to be significantly upregulated by 3.5-folds in RPE-choroid-sclera complex at day 10 after laser induction as compared to the baseline. Immunofluorescence analysis showed that Epo was mainly expressed around the vascular endothelial cells in the RPE-choroid-sclera complex. Intravitreal injection of siRNA targeting Epo reduced 40% Epo expression and 40% CNV lesion areas as compared to the scramble control. However, EPO variants were not associated with neovascular AMD nor PCV in the Chinese population.

CONCLUSIONS

This study revealed the promotion of human endothelial cell tube formation in vitro and choroid sprouting ex vivo by EPO, and the reduction of laser-induced CNV in vivo by Epo RNA interference.

TRANSLATIONAL RELEVANCE

Targeting EPO could be a potential additional treatment for CNV-related diseases.

Can Erythropoietin Reduce Hypoxemic Neurological Damages in Neonates With Congenital Heart Defects?

Congenital heart defects (CHD), the most common cause of birth defects with increasing birth prevalence, affect nearly 1% of live births worldwide. Cyanotic CHD are characterized by hypoxemia, with subsequent reduced oxygen delivery to the brain, especially critical during brain development, beginning in the fetus and continuing through the neonatal period. Therefore, neonates with CHD carry a high risk for neurological comorbidities, even more frequently when there are associated underlying genetic disorders. We review the currently available knowledge on potential prevention strategies to reduce brain damage induced by hypoxemia during fetal development and immediately after birth, and the role of erythropoietin (EPO) as a potential adjunctive treatment. Maternal hyper-oxygenation had been studied as a potential therapeutic to improve fetal oxygenation. Despite demonstrating some effectiveness, maternal hyper-oxygenation has proven to be impractical for extensive clinical application, thus prompting the investigation of specific pathways for pharmacological intervention. Among those, the role of antioxidant pathways and Hypoxia Inducible Factors (HIF) have been studied for their involvement in the protective response to hypoxic injury. One of the proteins induced by HIF, EPO, has properties of being anti-apoptotic, antioxidant, and protective for neurons, astrocytes, and oligodendrocytes. In human trials, EPO administration in neonates with hypoxic ischemic encephalopathy (HIE) significantly reduced the neurological hypoxemic damages in several reported studies. Currently, it is unknown if the mechanisms of pathophysiology of cyanotic CHD are like HIE. Neonates with cyanotic CHD are exposed to both chronic hypoxemia and episodes of acute ischemia-reperfusion injury when undergo cardiopulmonary bypass surgery requiring aortic cross-clamp and general anesthesia. Our review supports future trials to evaluate the potential efficiency of EPO in reducing the hypoxemic neurologic damages in neonates with CHD. Furthermore, it suggests the need to identify early biomarkers of hypoxia-induced neurological damage, which must be sensitive to the neuroprotective effects of EPO.