Decrease in incidence of bronchopulmonary dysplasia with erythropoietin administration in preterm infants: a retrospective study

Endothelial progenitor cells in pregnancy-related diseases

Placental neovascularization plays a crucial role in fetomaternal circulation throughout pregnancy and is dysregulated in several pregnancy-related diseases, including preeclampsia, gestational diabetes mellitus, and fetal growth restriction. Endothelial progenitor cells (EPCs) are a heterogeneous population of cells that differentiate into mature endothelial cells, which influence vascular homeostasis, neovascularization, and endothelial repair. Since their discovery in 1997 by Asahara et al., the role of EPCs in vascular biology has garnered a lot of interest. However, although pregnancy-related conditions are associated with changes in the number and function of EPCs, the reported findings are conflicting. This review discusses the discovery, isolation, and classification of EPCs and highlights discrepancies between current studies. Overviews of how various diseases affect the numbers and functions of EPCs, the role of EPCs as biomarkers of pregnancy disorders, and the potential therapeutic applications involving EPCs are also provided.

Erythropoietin for preventing bronchopulmonary dysplasia in preterm infants: A systematic review and meta-analysis

BACKGROUND

Recombinant erythropoietin (rEPO) has erythropoiesis and anti-inflammatory properties that might help reduce lung injury in preterm infants.

OBJECTIVE

To conduct a systematic review and meta-analysis to evaluate the possible role of rEPO in altering the risk of bronchopulmonary dysplasia (BPD).

METHODS

PubMed, EMBASE, Web of Science, and the Cochrane Library databases were searched to identify randomized controlled trials (RCTs) that evaluated the effects of rEPO for the prevention of BPD in preterm infants.

RESULTS

Fourteen studies (3199 infants) were included. Our results could not demonstrate a significant effect of rEPO on the incidence of BPD36 (risk ratio [RR]: 0.97, 95% confidence interval [CI]: 0.87-1.09, p = 0.63, I²  = 0, 12 RCTs, high-quality evidence), BPD28 (RR: 1.28, 95% CI: 0.91-1.79, p = 0.15, I²  = 17%, three RCTs, low-quality evidence) and oxygen dependence days. The test for subgroup analysis by administration route of rEPO showed similar outcomes above. Some of the included trials reported a significant effect of intravenous rEPO on reduction of sepsis (RR: 0.82, 95% CI: 0.70-0.96, p = 0.01, I²  = 0, high-quality evidence) and any stage necrotizing enterocolitis (NEC) (RR: 0.75, 95% CI: 0.59-0.94, p = 0.01, I²  = 0, moderate-quality evidence). The incidence of mortality and stage II or higher NEC was comparable in rEPO and control infants.

CONCLUSION

Our results suggest that rEPO does not affect the risk of developing BPD in preterm infants. Adequately powered RCTs are required to further confirm these findings.

Pharmacotherapy in Bronchopulmonary Dysplasia: What Is the Evidence?

Bronchopulmonary Dysplasia (BPD) is a multifactorial disease affecting over 35% of extremely preterm infants born each year. Despite the advances made in understanding the pathogenesis of this disease over the last five decades, BPD remains one of the major causes of morbidity and mortality in this population, and the incidence of the disease increases with decreasing gestational age. As inflammation is one of the key drivers in the pathogenesis, it has been targeted by majority of pharmacological and non-pharmacological methods to prevent BPD. Most extremely premature infants receive a myriad of medications during their stay in the neonatal intensive care unit in an effort to prevent or manage BPD, with corticosteroids, caffeine, and diuretics being the most commonly used medications. However, there is no consensus regarding their use and benefits in this population. This review summarizes the available literature regarding these medications and aims to provide neonatologists and neonatal providers with evidence-based recommendations.

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.

Prediction Model for Bronchopulmonary Dysplasia in Preterm Newborns

OBJECTIVE: To develop a multifactorial model that allows the prediction of bronchopulmonary dysplasia (BPD) in preterm newborns. MATERIALS AND METHODS: A single-center retrospective study of infants born below 32 + 0 weeks gestational age. We created a receiver operating characteristic curve to assess the multifactorial BPD risk and calculate the BPD risk accuracy using the area under the curve (AUC). BPD risk was categorized using a multifactorial predictive model based on the weight of the evidence. RESULTS: Of the 278 analyzed preterm newborns, 127 (46%) developed BPD. The significant risk factors for BPD in the multivariate analysis were gestational age, number of red blood cell concentrate transfusions, number of surfactant administrations, and hemodynamically significant patent ductus arteriosus. The combination of these factors determined the risk of developing BPD, with an AUC value of 0.932. A multifactorial predictive model based on these factors, weighted by their odds ratios, identified four categories of newborns with mean BPD risks of 9%, 59%, 82%, and 100%. CONCLUSION: A multifactorial model based on easily available clinical factors can predict BPD risk in preterm newborns and inform potential preventive measures.

Rates of Bronchopulmonary Dysplasia Following Implementation of a Novel Prevention Bundle

IMPORTANCE

Bronchopulmonary dysplasia (BPD) rates in the United States remain high and have changed little in the last decade.

OBJECTIVE

To develop a consistent BPD prevention bundle in a systematic approach to decrease BPD.

DESIGN, SETTING, AND PARTICIPANTS

This quality improvement study included 484 infants with birth weights from 501 to 1500 g admitted to a level 3 neonatal intensive care unit in the Kaiser Permanente Southern California system from 2009 through 2019. The study period was divided into 3 periods: 1, baseline (2009); 2, initial changes based on ongoing cycles of Plan-Do-Study-Act (2010-2014); and 3, full implementation of successive Plan-Do-Study-Act results (2015-2019).

INTERVENTIONS

A BPD prevention system of care bundle evolved with a shared mental model that BPD is avoidable.

MAIN OUTCOMES AND MEASURES

The primary outcome was BPD in infants with less than 33 weeks' gestational age (hereafter referred to as BPD <33). Other measures included adjusted BPD <33, BPD severity grade, and adjusted median postmenstrual age (PMA) at hospital discharge. Balancing measures were adjusted mortality and adjusted mortality or specified morbidities.

RESULTS

The study population included 484 infants with a mean (SD) birth weight of 1070 (277) g; a mean (SD) gestational age of 28.6 (2.9) weeks; 252 female infants (52.1%); and 61 Black infants (12.6%). During the 3 study periods, BPD <33 decreased from 9 of 29 patients (31.0%) to 3 of 184 patients (1.6%) (P < .001 for trend); special cause variation was observed. The standardized morbidity ratio for the adjusted BPD <33 decreased from 1.2 (95% CI, 0.7-1.9) in 2009 to 0.4 (95% CI, 0.2-0.8) in 2019. The rates of combined grades 1, 2, and 3 BPD decreased from 7 of 29 patients (24.1%) to 17 of 183 patients (9.3%) (P < .008 for trend). Grade 2 BPD rates decreased from 3 of 29 patients (10.3%) to 5 of 183 patients (2.7%) (P = .02 for trend). Adjusted median PMA at home discharge decreased by 2 weeks, from 38.2 (95% CI, 37.3-39.1) weeks in 2009 to 36.8 (95% CI, 36.6-37.1) weeks during the last 3 years (2017-2019) of the full implementation period. Adjusted mortality was unchanged, whereas adjusted mortality or specified morbidities decreased significantly.

CONCLUSIONS AND RELEVANCE

A sustained low rate of BPD was observed in infants after the implementation of a detailed BPD system of care.

EPO enhances the protective effects of MSCs in experimental hyperoxia-induced neonatal mice by promoting angiogenesis

Bronchopulmonary dysplasia (BPD) is the most common type of chronic lung disease in infancy; however, there is no effective treatment for it. In the present study, a neonatal mouse BPD model was established by continuous exposure to high oxygen (HO) levels. Mice were divided randomly into 5 groups: control, BPD, EPO, MSCs, and MSCs+EPO. At 2 weeks post-treatment, vessel density and the expression levels of endothelial growth factor (VEGF), stromal cell-derived factor-1 (SDF-1), and its receptor C-X-C chemokine receptor type 4 (CXCR4) were significantly increased in the MSC+EPO group compared with the EPO or MSCs group alone; moreover, EPO significantly enhanced MSCs proliferation, migration, and anti-apoptosis ability in vitro. Furthermore, the MSCs could differentiate into cells that were positive for the type II alveolar epithelial cell (AECII)-specific marker surfactant protein-C, but not positive for the AECI-specific marker aquaporin 5. Our present results suggested that MSCs in combination with EPO could significantly attenuate lung injury in a neonatal mouse model of BPD. The mechanism may be by the indirect promotion of angiogenesis, which may involve the SDF-1/CXCR4 axis.

Dose-dependent exacerbation of ventilation-induced lung injury by erythropoietin in preterm newborn lambs

Erythropoietin (EPO) is being trialled in preterm infants to reduce brain injury, but high doses increase lung injury in ventilated preterm lambs. We aimed to determine whether early administration of lower doses of EPO could reduce ventilation-induced lung injury and systemic inflammation in preterm lambs. Ventilation was initiated in anaesthetized preterm lambs [125 ± 1 (SD) days gestation] using an injurious strategy for the first 15 min. Lambs were subsequently ventilated with a protective strategy for a total of 2 h. Lambs were randomized to receive either intravenous saline (Vent; n = 7) or intravenous 300 ( n = 5), 1,000 (EPO1000; n = 5), or 3,000 (EPO3000; n = 5) IU/kg of human recombinant EPO via an umbilical vein. Lung tissue was collected for molecular and histological assessment of inflammation and injury and compared with unventilated control lambs (UVC; n = 8). All ventilated groups had similar blood gas and ventilation parameters, but EPO1000 lambs had a lower fraction of inspired oxygen requirement and lower alveolar–arterial difference in oxygen. Vent and EPO lambs had increased lung interleukin (IL)-1β, IL-6, and IL-8 mRNA, early lung injury genes connective tissue growth factor, early growth response protein 1, and cysteine-rich 61, and liver serum amyloid A3 mRNA compared with UVCs; no difference was observed between Vent and EPO groups. Histological lung injury was increased in Vent and EPO groups compared with UVCs, but EPO3000 lambs had increased lung injury scores compared with VENT only. Early low-doses of EPO do not exacerbate ventilation-induced lung inflammation and injury and do not provide any short-term respiratory benefit. High doses (≥3,000 IU/kg) likely exacerbate lung inflammation and injury in ventilated preterm lambs.

NEW & NOTEWORTHY Trials are ongoing to assess the efficacy of erythropoietin (EPO) to provide neuroprotection for preterm infants. However, high doses of EPO increase ventilation-induced lung injury (VILI) in preterm lambs. We investigated whether early lower doses of EPO may reduce VILI. We found that lower doses did not reduce, but did not increase, VILI, while high doses (≥3,000 IU/kg) increase VILI. Therefore, lower doses of EPO should be used in preterm infants, particularly those receiving respiratory support.

Bronchopulmonary Dysplasia: An Update of Current Pharmacologic Therapies and New Approaches

Bronchopulmonary dysplasia (BPD) remains the most prevalent long-term morbidity of surviving extremely preterm infants and is associated with significant health care utilization in infancy and beyond. Recent advances in neonatal care have resulted in improved survival of extremely low birth weight (ELBW) infants; however, the incidence of BPD has not been substantially impacted by novel interventions in this vulnerable population. The multifactorial cause of BPD requires a multi-pronged approach for prevention and treatment. New approaches in assisted ventilation, optimal nutrition, and pharmacologic interventions are currently being evaluated. The focus of this review is the current state of the evidence for pharmacotherapy in BPD. Promising future approaches in need of further study will also be reviewed.

Timing of erythropoietin modified mesenchymal stromal cell transplantation for the treatment of experimental bronchopulmonary dysplasia

The aim of this study is to optimize the timing of erythropoietin gene modified mesenchymal stem cells (EPO‐MSCs) transplantation for bronchopulmonary dysplasia (BPD). Three weeks post‐operation, the results indicated that the damage of airway structure and apoptosis were significantly decreased, the proliferation was increased in three EPO‐MSCs transplantation groups as compared with BPD mice. Moreover, the inflammation cytokines were improvement in early EPO‐MSCs injection mice than in BPD mice, but there was no significant difference between late injection and BPD groups. Furthermore, the protein expression ratio of p‐p38/p38MAPK was down‐regulation in early mice but not in late transplantation mice. Our findings suggest that EPO‐MSCs maybe attenuate BPD injury in early than in late administration by inhibiting inflammation response through down‐regulation of the p38MAPK signalling pathway.

Mesenchymal stem cells in combination with erythropoietin repair hyperoxia-induced alveoli dysplasia injury in neonatal mice via inhibition of TGF-β1 signaling

The aim of the present study is to investigate the protection effects of bone marrow mesenchymal stem cells (MSCs) in combination with EPO against hyperoxia-induced bronchopulmonary dysplasia (BPD) injury in neonatal mice. BPD model was prepared by continuous high oxygen exposure, 1×106 bone marrow MSCs and 5000U/kg recombinant human erythropoietin (EPO) were injected respectively. Results showed that administration of MSCs, EPO especially MSCs+EPO significant attenuated hyperoxia-induced lung damage with a decrease of fibrosis, radical alveolar counts and inhibition of the occurrence of epithelial-mesenchymal transition (EMT). Furthermore, MSCs+EPO co-treatment more significantly suppressed the levels of transforming growth factor-β1(TGF-β1) than MSCs or EPO alone. Collectively, these results suggested that MSCs, EPO in particular MSCs+EPO co-treatment could promote lung repair in hyperoxia-induced alveoli dysplasia injury via inhibition of TGF-β1 signaling pathway to further suppress EMT process and may be a promising therapeutic strategy.

A Pathogenic Relationship of Bronchopulmonary Dysplasia and Retinopathy of Prematurity? A Review of Angiogenic Mediators in Both Diseases

Bronchopulmonary dysplasia (BPD) and retinopathy of prematurity (ROP) are common and significant morbidities of prematurely born infants. These diseases have in common altered and pathologic vascular formation in the face of incomplete organ development. Therefore, it is reasonable to question whether factors affecting angiogenesis could have a joint pathogenic role for both diseases. Inhibition or induced expression of a single angiogenic factor is unlikely to be 100% causative or protective of either of BPD or ROP. It is more likely that interactions of multiple factors leading to disordered angiogenesis are present, increasing the likelihood of common pathways in both diseases. This review explores this possibility by assessing the evidence showing involvement of specific angiogenic factors in the vascular development and maldevelopment in each disease. Theoretical interactions of specific factors mutually contributing to BPD and ROP are proposed and, where possible, a timeline of the proposed relationships between BPD and ROP is developed. It is hoped that future research will be inspired by the theories put forth in this review to enhance the understanding of the pathogenesis in both diseases.

Prophylactic Early Erythropoietin for Neuroprotection in Preterm Infants: A Meta-analysis

CONTEXT

Recombinant human erythropoietin (rhEPO) is a promising pharmacological agent for neuroprotection in neonates.

OBJECTIVE

To investigate whether prophylactic rhEPO administration in very preterm infants improves neurodevelopmental outcomes in a meta-analysis of randomized controlled trials (RCTs).

DATA SOURCES

Medline, Embase, and the Cochrane Central Register of Controlled Trials were searched in December 2016 and complemented by other sources.

STUDY SELECTION

RCTs investigating the use of rhEPO in preterm infants versus a control group were selected if they were published in a peer-reviewed journal and reported neurodevelopmental outcomes at 18 to 24 months' corrected age.

DATA EXTRACTION

Data extraction and analysis followed the standard methods of the Cochrane Neonatal Review Group. The primary outcome was the number of infants with a Mental Developmental Index (MDI) <70 on the Bayley Scales of Infant Development. Secondary outcomes included a Psychomotor Development Index <70, cerebral palsy, visual impairment, and hearing impairment.

RESULTS

Four RCTs, comprising 1133 infants, were included in the meta-analysis. Prophylactic rhEPO administration reduced the incidence of children with an MDI <70, with an odds ratio (95% confidence interval) of 0.51 (0.31-0.81), P < .005. The number needed to treat was 14. There was no statistically significant effect on any secondary outcome.

CONCLUSIONS

Prophylactic rhEPO improved the cognitive development of very preterm infants, as assessed by the MDI at a corrected age of 18 to 24 months, without affecting other neurodevelopmental outcomes. Current and future RCTs should investigate optimal dosing and timing of prophylactic rhEPO and plan for long-term neurodevelopmental follow-up.

Glucocorticoids and erythropoietin in chronic lung disease of prematurity: Proliferative potential in lung fibroblast and epithelial cells exposed to tracheal aspirates

BACKGROUND

We investigated the effects of glucocorticoids, erythropoietin (EPO) and spironolactone (SPL) n human fetal lung fibroblasts and human alveolar epithelial cells exposed to tracheal aspirate fluid (TAF) from extremely premature infants with chronic lung disease (CLD), characterized by fibrosis and changes in the alveolar epithelium.

METHODS

Fibroblasts and epithelial cells (FHs 738Lu and A549, respectively) were treated with different concentrations of hydrocortisone (HDC), dexamethasone (DEX), betamethasone (BET), SPL, and EPO in the absence or presence of TAF from infants with CLD (gestational age, 25.3 ± 0.8 weeks; birthweight, 658 ± 77 g; postnatal age, 0-28 days) and assayed for proliferation.

RESULTS

Exposure to TAF resulted in a concentration-dependent proliferation of fibroblasts and epithelial cells. Proliferation of TAF-exposed fibroblasts was suppressed most significantly by 100 μmol/L DEX (21%, P = 0.046) and 300 mIU/mL EPO (18%, P = 0.02) and promoted most significantly by 0.4 μmol/L HDC (10%, P = 0.04). Epithelial proliferation was promoted by 4 μmol/L HDC (15%, P = 0.04), 10 μmol/L DEX (53%, P < 0.01), 0.2 μmol/L BET (56%, P < 0.01), and 300 mIU/mL EPO (35%, P < 0.01) in the presence of TAF. Treatment with glucocorticoids alone did not significantly affect fibroblast proliferation.

CONCLUSIONS

Glucocorticoids and EPO reduced fibroproliferation while promoting epithelial cell growth in vitro within certain dose ranges. Appropriate doses of glucocorticoids and EPO may be useful in the prevention and resolution of CLD in extremely premature infants.

Systemic endogenous erythropoietin and associated disorders in extremely preterm newborns

OBJECTIVE

To explore the association between concentrations of endogenous erythropoietin (EPO) in blood the first 2 weeks of life and neonatal disorders in extremely low gestational age newborns (ELGANs).

DESIGN

Prospective cohort study.

SETTING

Neonatal care units at 14 participating hospitals in the USA.

PATIENTS

867 children born before the 28th week of gestation from the ELGAN study cohort.

MAIN OUTCOME MEASURES

EPO blood concentrations were measured on postnatal days 1, 7 and 14. The following neonatal characteristics and disorders were registered: blood gases, early and late respiratory dysfunction, pulmonary deterioration, retinopathy of prematurity (ROP), necrotising enterocolitis (NEC) and bronchopulmonary dysplasia (BPD). We calculated the gestational age-adjusted ORs for having each disorder associated with an EPO blood concentration in the highest or lowest quartile, compared with infants whose EPO concentration was in the middle two quartiles on the corresponding day.

RESULTS

Newborns whose day-1 EPO was in the highest quartile were at increased risk for early and persistent respiratory dysfunction during the first 2 weeks of life, and NEC requiring surgery. The lowest EPO quartile on day 1 was associated with a decreased risk of moderate BPD. The association between low EPO and decreased risk of respiratory complications persisted on day 7. On day 14, being in the highest EPO quartile was associated with increased risk of ROP, and BPD not requiring ventilation assistance.

CONCLUSIONS

EPO blood concentrations in extremely preterm newborns during the first 2 weeks of life convey information about increased risks of bowel, lung and retinal diseases.

Ventilation strategies for preventing oxidative stress-induced injury in preterm infants with respiratory disease: an update

Reactive oxygen and nitrogen species are produced by several inflammatory and structural cells of the airways. The lungs of preterm newborns are susceptible to oxidative injury induced by both reactive oxygen and nitrogen species. Increased oxidative stress and imbalance in antioxidant enzymes may play a role in the pathogenesis of inflammatory pulmonary diseases. Preterm infants are frequently exposed to high oxygen concentrations, infections or inflammation; they have reduced antioxidant defense and high free iron levels which enhance toxic radical generation. Multiple ventilation strategies have been studied to reduce injury and improve outcomes in preterm infants. Using lung protective strategies, there is the need to reach a compromise between satisfaction of gas exchange and potential toxicities related to over-distension, derecruitment of lung units and high oxygen concentrations. In this review, the authors summarize scientific evidence concerning oxidative stress as it relates to resuscitation in the delivery room and to the strategies of ventilation.

Effect of delayed cord clamping (DCC) on breathing and transition at birth in very preterm infants

BACKGROUND

The effects of delayed cord clamping (DCC) on transition in preterm infants are important as this procedure is becoming increasingly recommended. The aim of this study was to compare the effects of DCC with an historical cohort.

METHOD

In this observational study, outcomes for infants ≤ 29 weeks were compared with a group born before the introduction of DCC. The intended intervention was DCC for 40s. Primary outcomes were the need for resuscitation and intubation in infants undergoing DCC, whilst taking note of their breathing during the procedure. Neonatal morbidities were analysed, including the association between breathing during DCC and outcome.

RESULTS

There were 62 infants in the DCC group, and 62 who received immediate cord clamping (ICC). Maternal and infant characteristics including gestational age (p = 0.76) and birth weight (p = 0.74) between groups were not significantly different. 70% of the DCC group breathed regularly at birth. Comparing the DCC and ICC groups, there was no significant difference in 1 min and 5 min Apgar scores or in the number requiring intubation at birth (p = 0.88). Likewise, admission temperatures were similar (p = 0.57). There was a significant increase in the rate of chronic lung disease in the DCC group (p = 0.013). When comparing the infants who breathed during DCC with the non-breathers; the non-breathing group was more likely to be intubated (p = 0.01), have chronic lung disease (p = 0.02), and severe intraventricular haemorrhage (p = 0.02).

CONCLUSION

DCC in these very preterm infants was well tolerated and the majority established spontaneous respiration whilst DCC was occurring. Infants who did not breathe during DCC had worse outcomes.

Correlation between erythropoietin level and degree of anemia in patients with acute upper gastrointestinal bleeding

AIM: To investigate the changes of erythropoietin (EPO) in patients with anemia caused by acute upper gastrointestinal bleeding (AUGIB) in different time periods, as well as the association between the degree of anemia and EPO.

METHODS: Seventy patients with anemia caused by AUGIB treated from June 2012 to June 2014 at Affiliated Hospital of University of Medicine served as an observation group, and 70 healthy people served as a control group. The levels of EPO in patients in the observation group were measured at the first, third and seventh day after the onset and compared with those in the healthy controls. The levels of EPO in patients with different degrees of anemia were compared.

RESULTS: The levels of EPO in the observation group patients showed an initial rising and then a downward trend from the first to the third and seventh day after the onset. The value of EPO peaked on the third day. Compared with the control group, the level of EPO on day 3 was significantly higher (P < 0.05). EPO values were higher than those in the control group on days 1 and 7, but the difference was not statistically significant (P > 0.05). The values of EPO in patients with severe anemia were significantly higher than those in patients with moderate or mild disease on days 1, 3 and 7 (P < 0.05).

CONCLUSION: In patients with AUGIB, EPO levels change over time. The degree of anemia in patients with AUGIB is closely related to the level of EPO. In patients with mild to moderate anemia, EPO levels do not change significantly, but EPO levels significantly increase in severe anemia.

Hypoxia-inducible factors promote alveolar development and regeneration

Understanding how alveoli and the underlying capillary network develop and how these mechanisms are disrupted in disease states is critical for developing effective therapies for lung regeneration. Recent evidence suggests that lung angiogenesis promotes lung development and repair. Vascular endothelial growth factor (VEGF) preserves lung angiogenesis and alveolarization in experimental O2-induced arrested alveolar growth in newborn rats, but combined VEGF+angiopoietin 1 treatment is necessary to correct VEGF-induced vessel leakiness. Hypoxia-inducible factors (HIFs) are transcription factors that activate multiple O2-sensitive genes, including those encoding for angiogenic growth factors, but their role during postnatal lung growth is incompletely understood. By inducing the expression of a range of angiogenic factors in a coordinated fashion, HIF may orchestrate efficient and safe angiogenesis superior to VEGF. We hypothesized that HIF inhibition impairs alveolarization and that HIF activation regenerates irreversible O2-induced arrested alveolar growth. HIF inhibition by intratracheal dominant-negative adenovirus (dnHIF-1α)-mediated gene transfer or chetomin decreased lung HIF-1α, HIF-2α, and VEGF expression and led to air space enlargement and arrested lung vascular growth. In experimental O2-induced arrested alveolar growth in newborn rats, the characteristic features of air space enlargement and loss of lung capillaries were associated with decreased lung HIF-1α and HIF-2α expression. Intratracheal administration of Ad.HIF-1α restored HIF-1α, endothelial nitric oxide synthase, VEGF, VEGFR2, and Tie2 expression and preserved and rescued alveolar growth and lung capillary formation in this model. HIFs promote normal alveolar development and may be useful targets for alveolar regeneration.

Association between red blood cell transfusion and bronchopulmonary dysplasia in preterm infants

Anemia and the need for transfusion of packed red blood cells (PRBCs) are common in preterm infants. PRBC transfusion increases the oxygen carrying capacity of hemoglobin and may result in higher rates of organ dysfunction. To determine whether PRBC transfusion in preterm infants is associated with an increased incidence of bronchopulmonary dysplasia (BPD), this retrospective study was performed on neonates with birth weights ≤ 1,500 g or gestational age ≤ 32 weeks admitted from August, 2008 to November, 2013. Infants who received PRBC transfusion before the diagnosis of BPD and those who did not receive PRBC transfusion or received PRBC transfusion after diagnosis of BPD were compared for incidence of BPD and other morbidities. Of 231 preterm infants, 137 received PRBC transfusion before BPD was diagnosed (group 1) and 94 did not (group 2). The incidence of BPD was significantly higher in group 1 than in group 2 (37.2% vs. 2.1%, P < 0.00001). After adjusting for potential risk factors, the adjusted odds ratio for BPD was 9.80 (95% confidence interval, 1.70-56.36; P = 0.01). This study demonstrated an association between PRBC transfusion and BPD in preterm infants. A cautious approach to PRBC transfusion in these infants is warranted.

Prophylactic erythropoietin exacerbates ventilation-induced lung inflammation and injury in preterm lambs

Ventilation-induced lung injury (VILI) of preterm neonates probably contributes to the pathogenesis of bronchopulmonary dysplasia (BPD). Erythropoietin (EPO) has been suggested as a therapy for BPD. The aim of this study was to determine whether prophylactic administration of EPO reduces VILI in preterm newborn lambs. Lambs at 126 days of gestation (term is 147 days) were delivered and ventilated with a high tidal volume strategy for 15 min to cause lung injury, then received gentle ventilation until 2 h of age. Lambs were randomized to receive intravenous EPO (5000 IU kg(-1): Vent+EPO; n = 6) or phosphate-buffered saline (Vent; n = 7) soon after birth: unventilated controls (UVC; n = 8) did not receive ventilation or any treatment. Physiological parameters were recorded throughout the experimental procedure. Samples of lung were collected for histological and molecular assessment of inflammation and injury. Samples of liver were collected to assess the systemic acute phase response. Vent+EPO lambs received higher F IO 2, P aO 2 and oxygenation during the first 10 min than Vent lambs. There were no differences in physiological indices beyond this time. Total lung injury score, airway wall thickness, inflammation and haemorrhage were higher in Vent+EPO lambs than in Vent lambs. Lung inflammation and early markers of lung and systemic injury were elevated in ventilated lambs relative to unventilated lambs; EPO administration further increased lung inflammation and markers of lung and systemic injury. Prophylactic EPO exacerbates VILI, which may increase the incidence and severity of long-term respiratory disease. More studies are required before EPO can be used for lung protection in preterm infants.

Recombinant human erythropoietin augments angiogenic responses in a neonatal rat model of cerebral unilateral hypoxia-ischemia

BACKGROUND

Recombinant human erythropoietin (rh-EPO) has been used as a drug to treat premature infant anemia for over a decade. In addition to its erythropoietic effect, rh-EPO has also been reported to have protective effects against brain injury.

OBJECTIVES

Our aim was to evaluate the levels of angiogenesis-related cells (CD34+ cells) and angiogenic factors (vascular endothelial growth factor, VEGF, and angiopoietin-1, Ang-1) in a neonatal rat model of cerebral unilateral hypoxia-ischemia (HI) and to identify the effects of rh-EPO on angiogenic responses.

METHODS

Postnatal day 3 (PD3) rats underwent permanent ligation of the right common carotid artery followed by 6% O2 for 4 h (HI) or sham operation and normoxic exposure (sham). Immediately after HI, the rats received a single intraperitoneal injection of rh-EPO (5 U/g) or saline. Angiogenesis-related cells (CD34+ cells) and angiogenic factors (VEGF and Ang-1) were examined on PD5, 7, 10 and 14.

RESULTS

Compared with the sham rats, the number of CD34+ cells in HI rats increased from PD5 to 7 but decreased from PD10 to 14. VEGF and Ang-1 mRNA levels both increased from PD5 to 14. CD34+ cells, VEGF and Ang-1 were all upregulated in rh-EPO-treated rats compared with HI rats.

CONCLUSIONS

In the present study, we show the angiogenic effects of rh-EPO in a rat model of neonatal cerebral unilateral HI. Our results highlight the powerful therapeutic potential of rh-EPO treatment of HI premature brain for the enhancement of angiogenic responses.

Circulating hematopoietic and endothelial progenitor cells in newborn infants: effects of gestational age, postnatal age and clinical stress in the first 3 weeks of life

INTRODUCTION

Circulating endothelial progenitor cells (EPC) are bone marrow derived progenitors that can be mobilized by erythropoietin or in response to tissue injury, and participate in vascular repair. EPC are understudied in human neonates. Whether EPC frequency in newborn infants may be influenced by gestational age or postnatal stress is unknown.

METHODS

Blood samples were collected on day 1 of life and weekly for 3 weeks from hospitalized neonates for plasma erythropoietin and flow cytometry analysis for CD34+, CD34+CD45-, CD34+VEGFR2+ and CD34+CD45-VEGFR2+ cells (EPC). Associations between CD34+ cell subsets and clinical parameters were studied.

RESULTS

Forty five patients were enrolled. An inverse correlation with gestational age was observed for CD34+ and CD34+ VEGFR2+ cell frequencies in whole blood (WB) on day 1 (p<0.05). In preterm infants, CD34+ cell frequency decreased with increased postnatal age (p=0.0001) and CD34+VEGFR2+ cell frequency was higher at week 3 than on day 1 in WB (p=0.0002). On day one, CD34+ and CD34+CD45- cell frequencies in the mononuclear cell fraction (MNC) were higher in preterm than term infants (p=0.035 and p=0.049, respectively) but CD34+CD45-VEGFR2+ cell frequency (median 2.2/million MNC versus 3.8/million MNC) and erythropoietin levels were not significantly different. Transient increases in EPC were observed in five infants with infection. Four preterm infants who developed bronchopulmonary dysplasia had undetectable or low EPC through the first 3 weeks of life.

CONCLUSIONS

Gestational age and postnatal age influenced circulating CD34+ and CD34+VEGFR2+ but not CD34+CD45-VEGFR2+ (EPC) cell frequencies. Circulating EPC in neonates may be influenced by clinical stress.

An update on pharmacologic approaches to bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is the most prevalent long-term morbidity in surviving extremely preterm infants and is linked to increased risk of reactive airways disease, pulmonary hypertension, post-neonatal mortality, and adverse neurodevelopmental outcomes. BPD affects approximately 20% of premature newborns, and up to 60% of premature infants born before completing 26 weeks of gestation. It is characterized by the need for assisted ventilation and/or supplemental oxygen at 36 weeks postmenstrual age. Approaches to prevention and treatment of BPD have evolved with improved understanding of its pathogenesis. This review will focus on recent advancements and detail current research in pharmacotherapy for BPD. The evidence for both current and potential future experimental therapies will be reviewed in detail. As our understanding of the complex and multifactorial pathophysiology of BPD changes, research into these current and future approaches must continue to evolve.