Genome wide DNA methylation analysis of alveolar capillary dysplasia lung tissue reveals aberrant methylation of genes involved in development including the FOXF1 locus.

BACKGROUND: Alveolar capillary dysplasia with or without misalignment of the pulmonary veins (ACD/MPV) is a lethal congenital lung disorder associated with a variety of heterozygous genomic alterations in the FOXF1 gene or its 60 kb enhancer. Cases without a genomic alteration in the FOXF1 locus have been described as well. The mechanisms responsible for FOXF1 haploinsufficiency and the cause of ACD/MPV in patients without a genomic FOXF1 variant are poorly understood, complicating the search for potential therapeutic targets for ACD/MPV. To investigate the contribution of aberrant DNA methylation, genome wide methylation patterns of ACD/MPV lung tissues were compared with methylation patterns of control lung tissues using the recently developed technique Methylated DNA sequencing (MeD-seq). RESULTS: Eight ACD/MPV lung tissue samples and three control samples were sequenced and their mutual comparison resulted in identification of 319 differentially methylated regions (DMRs) genome wide, involving 115 protein coding genes. The potentially upregulated genes were significantly enriched in developmental signalling pathways, whereas potentially downregulated genes were mainly enriched in O-linked glycosylation. In patients with a large maternal deletion encompassing the 60 kb FOXF1 enhancer, DNA methylation patterns in this FOXF1 enhancer were not significantly different compared to controls. However, two hypermethylated regions were detected in the 60 kb FOXF1 enhancer of patients harbouring a FOXF1 point mutation. Lastly, a large hypermethylated region overlapping the first FOXF1 exon was found in one of the ACD/MPV patients without a known pathogenic FOXF1 variation. CONCLUSION: This is the first study providing genome wide methylation data on lung tissue of ACD/MPV patients. DNA methylation analyses in the FOXF1 locus excludes maternal imprinting of the 60 kb FOXF1 enhancer. Hypermethylation at the 60 kb FOXF1 enhancer might contribute to FOXF1 haploinsufficiency caused by heterozygous mutations in the FOXF1 coding region. Interestingly, DNA methylation analyses of patients without a genomic FOXF1 variant suggest that abnormal hypermethylation of exon 1 might play a role in some ACD/MPV in patients.

Correlation between changes in brain natriuretic peptide and echocardiographic features in persistent pulmonary hypertension of newborn.

Objective: To investigate the correlation between changes in brain natriuretic peptide (BNP) and echocardiographic features in persistent pulmonary hypertension of newborn (PPHN).Patients and methods: A total of 76 patients with PPHN treated in our hospital from March 2017 to February 2018 were divided into mild group (n = 33), moderate group (n = 22) and severe group (n = 21) according to the pulmonary arterial systolic pressure, and they were compared with 30 normal newborns (control group) during the same period. All newborns underwent echocardiography, the BNP level was detected, and the correlation between echocardiographic features and BNP changes was analyzed.Results: The BNP level in control group was significantly lower than those in PPHN groups, and it was constantly increased from mild group to severe group (p<.05). There were no significant differences in left atrial diameter (LA) and left ventricular diameter (LV) among groups (p>.05), while there were significant differences in the right atrial diameter (RA), right ventricular diameter (RV) and peak velocity of tricuspid regurgitation (VTR) (p<.05). BNP had no correlations with LA and LV (p>.05), but had positive correlations with RA, RV and VTR (r = 0.527, 0.503 and 0.524, p<.05).Conclusion: The BNP level of patients with PPHN increases with the increasing severity of disease. BNP has close correlations with echocardiographic features of neonatal patients. Predicting the BNP changes via echocardiography is of certain value in guiding the clinical treatment.

Methemoglobin and the response to inhaled nitric oxide in persistent pulmonary hypertension of the newborn.

BACKGROUND: We aimed to investigate whether the change in methemoglobin levels (ΔMHb) predicts oxygenation response to inhaled nitric oxide (iNO) in persistent pulmonary hypertension of the newborn (PPHN) with lung disease, with or without pulmonary hypoplasia. METHODS: In this prospective observational study, infants were categorized based on ΔMHb and oxygenation response (ΔPaO2/FiO2) following iNO: ΔMHb ≤0 or ΔMHb>0, and ΔPaO2/FiO2 < 20 mmHg (Non-responder) or≥20 mmHg (Responder). ΔMHb levels were compared among infants with or without pulmonary hypoplasia. RESULTS: Among infants with pulmonary hypoplasia (n = 28), ΔMHb was not associated with an oxygenation response to iNO or survival without ECMO. Among infants without hypoplasia (n = 29), subjects with ΔMHb>0 following iNO (n = 21) had a greater ΔPaO2/FiO2 (median, 64 mmHg; IQR, 127; p < 0.01) and 100% survival without extracorporeal membrane oxygenation (ECMO) when compared to infants with ΔMHb ≤0 (n = 8; median 10 mmHg; IQR, 33). CONCLUSIONS: PPHN secondary to lung disease without hypoplasia with increased ΔMHb following iNO was associated with better oxygenation response and survival without ECMO compared to subjects without an increase in MHb.

Inhaled Epoprostenol for Pulmonary Hypertension Treatment in Neonates: A 12-Year Experience.

BACKGROUND: Persistent pulmonary hypertension of the newborn (PPHN) occurs in 10% of neonatal respiratory insufficiency. To selectively reduce pulmonary vascular resistance, several treatments have been tried. Inhaled epoprostenol (iPGI2) has been used for 12 years in our institution for the management of refractory PPHN despite the gaps in the literature to support this use. OBJECTIVES: The primary objective was to evaluate the efficacy of iPGI2 for PPHN. The secondary objectives were to describe its use in neonates and assess side effects. STUDY DESIGN: This retrospective cohort study included infants < 28 days with PPHN treated with iPGI2 in the neonatal or pediatric intensive care units of our institution between 2004 and 2016. RESULTS: We reviewed 43 patient' care episodes (mean gestational age of 36 weeks). This was an extremely ill population with 54% mortality rate. Oxygenation index improved significantly after 12-hour treatment (p = 0.047), with a rebound effect when discontinuing nebulization. By the end of the therapy, the fraction of inspired oxygen had significantly dropped (p = 0.0018). Echocardiographic markers tended to normalize during treatment. No potential side effects were reported. CONCLUSION: In these sick newborns, we observed an improvement in PPHN under iPGI2 without significant adverse effects. To our knowledge, this is the largest neonatal cohort reported to have received iPGI2 for PPHN.

Altered metabolites in newborns with persistent pulmonary hypertension.

BACKGROUND: There is an emerging evidence that pulmonary hypertension is associated with amino acid, carnitine, and thyroid hormone aberrations. We aimed to characterize metabolic profiles measured by the newborn screen (NBS) in infants with persistent pulmonary hypertension of the newborn (PPHN) METHODS: Nested case-control study from population-based database. Cases were infants with ICD-9 code for PPHN receiving mechanical ventilation. Controls receiving mechanical ventilation were matched 2:1 for gestational age, sex, birth weight, parenteral nutrition administration, and age at NBS collection. Infants were divided into derivation and validation datasets. A multivariable logistic regression model was derived from candidate metabolites, and the area under the receiver operator characteristic curve (AUROC) was generated from the validation dataset. RESULTS: We identified 1076 cases and 2152 controls. Four metabolites remained in the final model. Ornithine (OR 0.32, CI 0.26-0.41), tyrosine (OR 0.48, CI 0.40-0.58), and TSH 0.50 (0.45-0.55) were associated with decreased odds of PPHN; phenylalanine was associated with increased odds of PPHN (OR 4.74, CI 3.25-6.90). The AUROC was 0.772 (CI 0.737-0.807). CONCLUSIONS: In a large, population-based dataset, infants with PPHN have distinct, early metabolic profiles. These data provide insight into the pathophysiology of PPHN, identifying potential therapeutic targets and novel biomarkers to assess the response.

MiR-126a-5p is involved in the hypoxia-induced endothelial-to-mesenchymal transition of neonatal pulmonary hypertension.

Persistent pulmonary hypertension of the newborn (PPHN) is a clinical syndrome characterized by increased medial and adventitial thickness of the lung vasculature. The underlying mechanisms that regulate the cell phenotype alteration during PPHN remodeling are largely unknown. We randomly selected newborn rats that were exposed to hypoxia (10-12%) or room air for 2 weeks and used a microarray to identify the lung tissue microRNAs (miRNAs) involved in PPHN progression. The role of a key miRNA that affects the endothelial-to-mesenchymal transition (EndMT) in primary cultured rat pulmonary microvascular endothelial cells (RPMECs) was investigated. The expression of miR-126a-5p was elevated in the PPHN model according to microarray analysis. The relative expression of miR-126a-5p in RPMECs increased when they were exposed to hypoxia (P<0.05), consistent with the microarray results. Pecam1 expression decreased, whereas alpha-smooth muscle actin (α-SMA) increased in the hypoxic RPMECs. Knockdown of miR-126a-5p in RPMECs followed by treatment with hypoxia for 48 h resulted in a significant increase in the expression of Pecam1 and a reduction in α-SMA expression, with a simultaneous increase in PI3K (p85ß) and phosphorylation of AKT at serine 473 compared with the negative control. Finally, the circulating miR-126a-5p concentration was upregulated in the PPHN model compared with healthy neonates. We concluded that hypoxia changed the cell homeostasis and that miR-126a-5p was upregulated in PPHN, which is partly responsible for hypoxia-induced EndMT. The mechanism underlying the upregulation of miR-126a-5p by hypoxia probably acts through the p85-ß/p-AKT pathway.

The fetal circulation, pathophysiology of hypoxemic respiratory failure and pulmonary hypertension in neonates, and the role of oxygen therapy.

Neonatal hypoxemic respiratory failure (HRF), a deficiency of oxygenation associated with insufficient ventilation, can occur due to a variety of etiologies. HRF can result when pulmonary vascular resistance (PVR) fails to decrease at birth, leading to persistent pulmonary hypertension of newborn (PPHN), or as a result of various lung disorders including congenital abnormalities such as diaphragmatic hernia, and disorders of transition such as respiratory distress syndrome, transient tachypnea of newborn and perinatal asphyxia. PVR changes throughout fetal life, evident by the dynamic changes in pulmonary blood flow at different gestational ages. Pulmonary vascular transition at birth requires an interplay between multiple vasoactive mediators such as nitric oxide, which can be potentially inactivated by superoxide anions. Superoxide anions have a key role in the pathophysiology of HRF. Oxygen (O2) therapy, used in newborns long before our knowledge of the complex nature of HRF and PPHN, has continued to evolve. Over time has come the discovery that too much O2 can be toxic. Recommendations on the optimal inspired O2 levels to initiate resuscitation in term newborns have ranged from 100% (pre 1998) to the currently recommended use of room air (21%). Questions remain about the most effective levels, particularly in preterm and low birth weight newborns. Attaining the appropriate balance between hypoxemia and hyperoxemia, and targeting treatments to the pathophysiology of HRF in each individual newborn are critical factors in the development of improved therapies to optimize outcomes.

B-type natriuretic peptide: biomarker of persistent pulmonary hypertension of the newborn?

OBJECTIVE: We assessed the utility of plasma B-type natriuretic peptide (BNP) in infants with persistent pulmonary hypertension of the newborn (PPHN) in the prediction of inhaled nitric oxide (iNO) requirement. METHODS: This prospective study involved neonates (gestational age ≥ 34 weeks) with PPHN and confirmatory echocardiographic findings. Plasma BNP was assayed once within 12 hours of meeting criteria for iNO requirements and twice every 24 to 48 hours thereafter. RESULTS: Infants requiring iNO (n = 14) had higher first BNP levels compared with others (n = 5) (455.5 ± 350.6 vs. 30.1 ± 25.3 ng/dL, p < 0.003). The sensitivity, specificity, positive and negative predictive values, and 95% confidence intervals (CI) for plasma BNP greater than 30 ng/dL to predict iNO requirement were 100 (85-100), 80 (37-80), 94 (80-94), and 100 (46-100)%, respectively. Corresponding values at a cut-off plasma BNP concentration greater than 85 ng/dL were 79 (62-79), 100 (53-100), 100 (79-100), and 63 (33-63)%, respectively. CONCLUSION: BNP had excellent sensitivity and negative predictive value for iNO requirement and above 30 ng/dl maybe a useful prognostic biomarker in PPHN.

Successful Use of Extracorporeal Membrane Oxygenation in a Neonate With Arterial pH Less Than 6.6.

Challenges in extracorporeal membrane oxygenation (ECMO) support include defining appropriate patient selection criteria and prognostic factors. Severe acidosis prior to ECMO deployment is often considered a relative contraindication and an independent predictor of mortality. We present a case of a term infant, with persistent pulmonary hypertension of the newborn with severe pre-ECMO acidosis (arterial blood pH 6.596) in whom venoarterial ECMO was instituted successfully without major circuit or patient-associated complications. At seven months of age, he exhibited age-appropriate neurodevelopmental milestones. We therefore report this instance of successful use of ECMO in the setting of extreme acidosis.

Oxygen saturation index and severity of hypoxic respiratory failure.

BACKGROUND: The oxygenation index (OI = mean airway pressure, MAP × FiO2 × 100 : PaO2) is used to assess the severity of hypoxic respiratory failure (HRF) and persistent pulmonary hypertension of the newborn (PPHN). An indwelling arterial line or arterial punctures are necessary to obtain PaO2 for the calculation of OI. Oxygenation can be continuously and noninvasively assessed using pulse oximetry. The use of the oxygen saturation index (OSI = MAP × FiO2 × 100 : SpO2) can be an alternate method of assessing the severity of HRF. OBJECTIVE: To evaluate the correlation between OSI and OI in the following: (1) neonates with HRF and (2) a lamb model of meconium aspiration syndrome. METHODS: Human neonates: a retrospective chart review of 74 ventilated late preterm/term neonates with indwelling arterial access and SpO2 values in the first 24 h of life was conducted. OSI and OI were calculated and correlated. Lamb model: arterial blood gases were drawn and preductal SpO2 was documented in 40 term newborn lambs with asphyxia and meconium aspiration. OI and OSI were calculated and correlated with pulmonary vascular resistance (PVR). RESULTS: Mean values of OSI and OI showed a correlation coefficient of 0.952 in neonates (mean value of 308 observations in 74 neonates) and 0.948 in lambs (mean value of 743 observations in 40 lambs). In lambs, with increasing PVR, there was a decrease in OI and OSI. CONCLUSION: OSI correlates significantly with OI in infants with HRF. This noninvasive measure may be used to assess the severity of HRF and PPHN in neonates without arterial access.

The effect of inhaled nitric oxide therapy on thromboelastogram in newborns with persistent pulmonary hypertension.

UNLABELLED: Studies about the effects of inhaled nitric oxide (iNO) on bleeding time and platelet aggregation in newborns are limited in number and have inconclusive results. Thromboelastogram (TEG) shows the combined effects of coagulation factors and platelet functions. In this preliminary study, we aimed to evaluate the effects of iNO on coagulation using TEG in newborns with persistent pulmonary hypertension (PPH). TEG assays were performed in 10 term infants receiving iNO treatment for PPH and 32 healthy term infants. Samples of the iNO group were collected before and during iNO. Clot reaction time (R), clot kinetics (K), maximum amplitude (MA), and alpha angle were obtained from the TEG tracing. TEG-R values were statistically higher during iNO treatment (7.75 ± 3.34) when compared to the values before iNO (4.83 ± 1.38) and the healthy controls (3.75 ± 0.98). The alpha angle was lower in iNO treated infants at both periods (before iNO, 55.33 ± 8.58; during iNO, 42.90 ± 18.34) compared to the control group (64.95 ± 6.88). MA values before iNO treatment were the lowest (44.43 ± 14.09) and improved with the iNO treatment (48.40 ± 9.49) despite still being lower compared to the controls (53.67 ± 5.56). CONCLUSION: Both PPH and iNO may negatively effect in vitro coagulation tests. Therefore, newborns with PPH requiring iNO treatment should be closely monitored for coagulation problems.

[Changes in plasma levels of atrial natriuretic peptide, endothelin-1 and von Willebrand factor among newborns with persistent pulmonary hypertension].

OBJECTIVE: To investigate the changes in plasma levels of atrial natriuretic peptide (ANP), endothelin-1 (ET-1) and von Willebrand factor (vWF), and their significance among newborns with persistent pulmonary hypertension (PPH). METHODS: Sixty-six newborns with PPH (case group) (mild: 26 cases; moderate: 21 cases; severe: 19 cases), as well as 40 newborns without PPH (control group) who were hospitalized in the same period, were enrolled. The control group underwent echocardiography on admission. The case group underwent echocardiography before treatment (with refractory hypoxemia) and after 7 days of treatment for measurement of pulmonary artery systolic pressure (PASP). Meanwhile, plasma levels of ANP, ET-1 and vWF were measured using ELISA. RESULTS: Before treatment, the case group had significantly higher plasma levels of ANP, ET-1 and vWF than the control group (P<0.05), and these indices increased as PASP rose. After 7 days of treatment, the children with mild or moderate PPH showed normal PASP, and their plasma levels of ANP, ET-1 and vWF were not significantly different from those of control group. The children with severe PPH had significant decreases in all indices, but they were significantly higher than those of the control group. Plasma levels of ANP, ET-1 and vWF were significantly positively correlated with PASP before and after treatment (P<0.01). CONCLUSIONS: Changes in plasma levels of ANP, ET-1 and vWF can reflect PASP in newborns with PPH during treatment. Dynamic monitoring of these indices can help to judge the severity of PPH and guide treatment.

Store-operated channels in the pulmonary circulation of high- and low-altitude neonatal lambs.

We determined whether store-operated channels (SOC) are involved in neonatal pulmonary artery function under conditions of acute and chronic hypoxia, using newborn sheep gestated and born either at high altitude (HA, 3,600 m) or low altitude (LA, 520 m). Cardiopulmonary variables were recorded in vivo, with and without SOC blockade by 2-aminoethyldiphenylborinate (2-APB), during basal or acute hypoxic conditions. 2-APB did not have effects on basal mean pulmonary arterial pressure (mPAP), cardiac output, systemic arterial blood pressure, or systemic vascular resistance in both groups of neonates. During acute hypoxia 2-APB reduced mPAP and pulmonary vascular resistance in LA and HA, but this reduction was greater in HA. In addition, isolated pulmonary arteries mounted in a wire myograph were assessed for vascular reactivity. HA arteries showed a greater relaxation and sensitivity to SOC blockers than LA arteries. The pulmonary expression of two SOC-forming subunits, TRPC4 and STIM1, was upregulated in HA. Taken together, our results show that SOC contribute to hypoxic pulmonary vasoconstriction in newborn sheep and that SOC are upregulated by chronic hypoxia. Therefore, SOC may contribute to the development of neonatal pulmonary hypertension. We propose SOC channels could be potential targets to treat neonatal pulmonary hypertension.

ABO blood group is associated with response to inhaled nitric oxide in neonates with respiratory failure.

BACKGROUND: Inhaled nitric oxide (iNO) reduces death or need for extracorporeal membrane oxygenation (ECMO) in infants with persistent pulmonary hypertension of the newborn (PPHN). However, the response to iNO is variable and only 50-60% of infants demonstrate a response to iNO. It is not known why only some infants respond to iNO. Adults and children with blood groups B or AB do not respond as well to iNO as those with blood groups O/A. METHODS/PRINCIPAL FINDINGS: To determine if blood group was associated with iNO response in newborn infants, a retrospective medical record review was done of infants admitted to a regional NICU from 2002-9 with a diagnosis of PPHN. Data were collected during the first twelve hours post-initiation of treatment. Of 86 infants diagnosed with PPHN, 23 infants had blood group A [18 received iNO], 21 had group B [18 with iNO], 40 had group O [36 with iNO], and 2 had group AB [both received iNO]. Change in PaO(2)/FiO(2) was less in infants with blood group A, of whom less than half were responders (ΔPaO(2)/FiO(2)>20%) at 12 h versus 90% of infants with either O or B. Race, sex, birth weight, gestational age, Apgar scores at 1 and 5 minutes, and baseline PaO(2)/FiO(2) were similar among groups. Outcomes including need for ECMO, death, length of ventilatory support, length of iNO use, and hospital stay were statistically not different by blood groups. CONCLUSIONS/SIGNIFICANCE: Our results indicate that blood group influences iNO response in neonates. We hypothesize that either there is genetic linkage of the ABO gene locus with vasoregulatory genes, or that blood group antigens directly affect vascular reactivity.

Oxidative stress and persistent pulmonary hypertension of the newborn treated with inhaled nitric oxide and different oxygen concentrations.

OBJECTIVES: The aim of this study was to determine the effects of inhaled NO with different oxygen concentrations on the inflammatory cascade in newborns with hypoxic respiratory failure secondary to persistent pulmonary hypertension. METHODS: 60 newborns received iNO and 30 of them received an initial oxygen concentration of 45% (group 1), while the other 30 newborns received an initial oxygen concentration of 80% (group 2). The levels of inflammatory cytokines (IL-6, IL-8, TNF-α) were measured. The clinical outcome was also recorded. RESULTS: The findings show that interleukin concentrations (IL-6, IL-8, TNF-α) were significantly decreased between 0 and 72 hours (p < 0.01) in the newborns exposed to initial oxygen concentration of 45% and significantly increased in the other group. CONCLUSIONS: When inhaled, NO was co-administered with concentration of O(2) <45%, anti-inflammatory responses occurred, in accord with evidence in the published literature. The benefits of iNO on the clinical outcome in the current study demonstrate that inhaled NO in both groups was associated with improved short-term oxygenation.

B-type natriuretic peptide and rebound during treatment for persistent pulmonary hypertension.

OBJECTIVE: To investigate whether serum B-type natriuretic peptide (BNP) is a useful biomarker in evaluating the course of persistent pulmonary hypertension of the newborn (PPHN) and the effectiveness of treatment. STUDY DESIGN: Prospective follow-up study of infants with clinical and echocardiographic signs of PPHN, who were treated with inhaled nitric oxide (iNO). Of 24 patients with PPHN who were treated, serum BNP levels were determined longitudinally in 21. BNP levels were compared between infants with (n = 6) and without rebound PPHN (n = 15). RESULTS: BNP levels in all infants with PPHN were not significantly different at the initial start of iNO. BNP levels decreased in both groups during iNO treatment. In the infants in whom rebound PPHN developed after weaning from iNO, a significantly higher increase was found in BNP (283 pmol/L to 1232 pmol/L) compared with that in infants without rebound (98 pmol/L to 159 pmol/L). This occurred before the onset of clinical deterioration. BNP again decreased significantly after iNO treatment was restarted. CONCLUSIONS: BNP, a biomarker of cardiac ventricular strain, proved to be useful in evaluating the efficacy of PPHN treatment, and moreover, BNP helps to predict a rebound of PPHN.

Role of angiotensin-converting enzyme gene polymorphism in persistent pulmonary hypertension of the newborn.

AIM: To evaluate the association of angiotensin-converting enzyme (ACE) gene polymorphism with risk/severity of persistent pulmonary hypertension of the newborn (PPHN) among at risk infants. METHODS: Infants ≥ 34 weeks with respiratory distress at birth were recruited. PPHN was diagnosed clinically and by cardiac echocardiogram. Control group consisted of infants with respiratory distress who did not develop PPHN. ACE genotyping (DD, II, DI genotypes) and serum ACE levels were determined. RESULTS: A total of 120 infants were included (PPHN = 44; control = 76). Frequency of ACE DD genotype was not different between the two groups of infants (25% versus 33%). Among PPHN infants, severity of illness did not differ between genotypes. Mean (SD) serum ACE levels [15 (9) versus 24 (13) versus 29 (14) U/L] were positively associated with the number of D alleles and inversely associated with infants' gestational age (GA) and level of cardiovascular support. CONCLUSION: Angiotensin-converting enzyme gene polymorphism did not impact the risk or severity of PPHN among infants ≥ 34 weeks GA.

Fetal pulmonary vascular remodeling in a rat model induced by hypoxia and indomethacin.

OBJECTIVE: This study sought to determine the effect of combined treatment of hypoxia plus indomethacin on pulmonary vascular remodeling in fetal rats. METHODS: Hypoxia and indomethacin were used to treat pregnant rats during 19-21 days of gestation. The adventitia, media, and intima of pulmonary arteries from fetal rats were assessed. Western blots were used for determining the abundance of smooth muscle specific alpha-actin protein (α-SMA), elastin, and endothelial nitric oxide synthase (eNOS) in lung tissues. Plasma brain-type natriuretic peptide (BNP) levels, reflecting the increased right ventricular load or pulmonary arterial pressure, were detected. RESULTS: The ratio of left ventricular free wall plus septum to right ventricular weight significantly increased in hypoxia plus indomethacin-treated group. The medial thickness percentage of pulmonary arteries of < 100 µm and ≥100 µm in diameter from hypoxia plus indomethacin-treated group was higher than that from control or single treatment group. Vascular elastin area percentage and immunostaining density of eNOS from the combined-treated group were higher than other groups. The relative abundance of α-SMA, elastin, and eNOS and plasma BNP levels in hypoxia plus indomethacin-treated group also significantly increased compared with other groups. CONCLUSIONS: Hypoxia and indomethacin had synergistic effect on fetal pulmonary vascular remodeling. This rat model induced by combined treatments can mimic human persistent pulmonary hypertension of the newborn.

Expression of HIF-1 alpha, VEGF and EPO in peripheral blood from patients with two cardiac abnormalities associated with hypoxia.

OBJECTIVES: HIF-1 alpha (hypoxia-inducible factor-1 alpha) mediates the responses of mammalian cells to hypoxia/ischemia by inducing the expression of adaptive gene products (e.g., vascular endothelial growth factor (VEGF) and erythropoietin (EPO)). Persistent pulmonary hypertension of the newborn (PPHN) and cyanotic congenital heart disease (CCHD) are common neonatal diseases considered as paradigms of hypoxemia. Since the expression HIF-1 alpha, VEGF and EPO in newborns diagnosed with these diseases has yet to be studied, we set out to define the expression of these genes in peripheral blood from newborn infants diagnosed with PPHN and CCHD. DESIGN AND METHODS: The mRNA transcripts encoding HIF-1 alpha, VEGF and EPO were measured by RT-PCR in healthy newborn infants and infants diagnosed with PPHN and CCHD. RESULTS: An important increase in HIF-1 alpha expression was observed in both pathological conditions, accompanied by significant increases in VEGF and EPO expression when compared to healthy infants. CONCLUSIONS: HIF-1 alpha mRNA expression increases in newborn infants with PPHN or CCHD, as does the expression of its target genes VEGF and EPO.