Hyperferritinemia among very-low-birthweight infants in Thailand: a prospective cohort study

OBJECTIVES

To determine the incidence of hyperferritinemia in VLBW infants, and its association with neonatal morbidity.

STUDY DESIGN

Prospective cohort study in a tertiary-level hospital in Bangkok, from March 2022 to January 2023. Serum ferritin (SF) was measured in VLBW infants at one month and repeated monthly for those with hyperferritinemia (SF > 300 ng/mL).

RESULTS

Gestational age and birth weight were 29.7 ± 2.4 weeks (mean ± SD) and 1100 g (IQR, 830, 1340). Hyperferritinemia was identified in 30.1% (95% CI, 20.8-41.4). After adjustment, only packed red cell transfusion >15 mL/kg was associated with hyperferritinemia (RR 3.1; 95% CI, 1.5-6.4). All elevated SF levels returned to normal within four months. Hyperferritinemia was associated with severe bronchopulmonary dysplasia (RR 2.3, 95% CI, 1.0-5.4) and retinopathy of prematurity (RR 3.5, 95% CI, 1.4-8.6).

CONCLUSION

Hyperferritinemia is common among our VLBW infants, particularly after transfusion, and is associated with severe BPD and ROP.

Can red cell distribution width in very low birth weight infants predict bronchopulmonary dysplasia?

Red cell distribution width (RDW) is a useful marker for assessing the severity and prognosis of various diseases in adults. However, whether it is applicable to children, especially in newborns, has not been determined.This study aimed to investigate the RDW values of preterm infants and evaluate whether RDW values in the early days of life can predict bronchopulmonary dysplasia (BPD) development.One hundred and eight infants born at <30 weeks of gestation with a birth weight of <1500 g participated in this retrospective study. RDW values measured at birth, 7 days (D7), and 28 days (D28) after birth were reviewed. The changes in RDW values in the first month of life were analyzed, and we evaluated the relationship between RDW and BPD.The mean RDW values at birth, D7, D28 and the change from birth to D7 were 16.2 ± 0.1%, 17.5 ± 0.2%, 17.6 ± 0.2% and 1.3 ± 1.8%, respectively. RDW at birth was lower in the infants born at <28 weeks' gestational age than in those born at ≥28 weeks' gestational age (15.7 ± 0.3 vs 16.4 ± 0.2, P = .024). RDW values of both groups increased during the first week after birth and did not differ significantly at D7. The levels remained similar at 1 month of age. RDW at birth, D7, and D28 and the changes in RDW from birth to D7 were not correlated with the development of BPD independent of its severity.The usefulness of RDW as a predictor of BPD development remains questionable and requires further study.

An Evaluation to Establish the Acceptable Serum Triglyceride Levels in Neonates Receiving Intravenous Fat Emulsion Infusion in a Multicenter Retrospective Study

OBJECTIVE

This study aimed to establish neonatal serum triglyceride (TG) level reference ranges during lipid infusion and correlate peak TG with neonatal outcomes.

STUDY DESIGN

This is a retrospective review of 356 neonates with 696 TG measures obtained in four neonatal intensive care units between 2015 and 2017. TG was evaluated collectively to establish a reference range and a threshold limit. To analyze the effects of a higher TG threshold, neonates were categorized by their peak TG: <180 (TG<180), 180 to 400 (TG180-400), and > 400 mg/dL (TG>400). Univariable and multivariable regression models were constructed to compare peak TG to patient characteristic and clinical outcomes.

RESULTS

The frequency of TG > 400 mg/dL was 5% and found only in neonates weighing < 1.5 kg. Neonates in the TG180-400 (n = 91) group were significantly lower in birth weight and gestational age, had lower 5-minute APGAR scores, and had increased ventilatory requirement when compared with neonates in the TG<180 (n = 240) group (all p < 0.001). The TG180-400 group had increased risk of severe intraventricular hemorrhage (p = 0.02) and bronchopulmonary dysplasia (p = 0.03). Elevated TG was associated with mortality (odds ratio [OR]: 14.4, p < 0.001) in univariable analysis, but the relationship weakened (OR: 4.4, p = 0.05) after adjusting for comorbidities in multivariable logistic regression.

CONCLUSION

It is unclear if the adverse outcomes seen in neonates with higher peak TG were due to elevated TG alone, or whether illness severity predicted the increased TG. More prospective studies are needed to further delineate the relationships.

Decreased neutrophil levels in bronchopulmonary dysplasia infants

BACKGROUND

Previous studies have indicated that inflammation plays an important role in the occurrence and development of bronchopulmonary dysplasia (BPD); however, there were rare researches about the changes of neutrophils and their influence on the prognosis of BPD. Hence, we aimed to explore the changes in the number of peripheral blood neutrophils (PBNs), and the relationship between these changes and susceptibility to pulmonary infection among children with BPD.

METHODS

Firstly, the gene expression of lung tissues and the number of PBNs were respectively detected by RNA sequencing and complete blood count in the 85% O₂-induced BPD model rats. Then it was analyzed the number of PBNs after birth and the incidence of pneumonia within 6 months of corrected age (CA) after discharge among full-term infants (FTIs: gestational age [GA] between 37^0/7 and 41^6/7 weeks, n = 88), preterm infants with (PTIs-BPD: GA <32 weeks, n = 35) or without BPD (PTIs-nBPD: GA <32 weeks, n = 41).

RESULTS

The levels of S100A8 and S100A9 mRNAs were significantly decreased in the lungs of BPD rats. Moreover, the number of PBNs was also decreased in BPD rats. The number of PBNs at birth in FTIs was significantly greater than that in PTIs-BPD or in PTIs-nBPD (p < 0.001), while those between PTIs-BPD and PTIs-nBPD showed no significant difference (p > 0.05). Although the peripheral blood neutrophils decreased overall after birth in both PTIs-nBPD and PTIs-BPD groups, only the reduction in the PTIs-BPD group was significant (p < 0.001). Importantly, at 36-37 weeks of postmenstrual age (PMA), the number of PBNs in PTIs-BPD was significantly fewer than that in PTIs-nBPD (p < 0.001). In addition, PTIs-BPD had a significantly higher incidence of pneumonia than PTIs-nBPD within 6 months of CA after discharge (p < 0.01).

CONCLUSION

The number of PBNs in PTIs-BPD decreased progressively when compared to that in PTIs-nBPD, which might contribute to their susceptibility to pulmonary infection.

Non-invasive assessment of oxidative stress in preterm infants

Preterm newborns have an immature antioxidant defense system and are especially susceptible to oxidative stress. Resuscitation, mechanical ventilation, intermittent hypoxia and apneic episodes require frequently oxygen supplementation which leads to oxidative stress in preterm newborns. The consequences of oxidative damage are increased short and long-term morbidities, neurodevelopmental impairment and increased mortality. Oxidative stress biomarkers are determined in blood samples from preterm children during their stay in neonatal intensive care units especially for research purposes. However, there is a tendency towards reducing invasive and painful techniques in the NICU (Neonatal Intensive Care Unit) and avoiding excessive blood extractions procedures. In this paper, it has been described some studies that employed non-invasive samples to determine oxidative stress biomarkers form preterm infants in order to perform a close monitoring biomarker with a significant greater predictive value. Among these methods we describe a previously developed and validated high-performance liquid chromatography tandem mass spectrometry method that allow to accurately determine the most reliable biomarkers in biofluids, which are non-invasively and painlessly obtained.

Increased serum Th2 chemokine levels are associated with bronchopulmonary dysplasia in premature infants

Bronchopulmonary dysplasia (BPD) is one of the most common chronic inflammatory lung disease of premature infants, with serious short- and long-term consequences. Early identification of premature infants at risk of BPD is critical to preventing the pathogenesis of disease. Thus, in the present study, we recruited 126 premature infants, collected peripheral blood samples at different time points during early life, and measured the concentration of Th1 (MCP-1, IP-10, and MIG) and Th2 (eotaxin-1, eotaxin-2, and MCP-4) chemokines in serum. We found serum eotaxin-2 levels were significantly higher in the BPD group than in the non-BPD group on day 1 [1662 pg/ml vs. 1221 pg/ml, P < 0.05], day 7 [1533 pg/ml vs. 1089 pg/ml, P < 0.05], and day 14 [1246 pg/ml vs. 704 pg/ml, P < 0.05] after birth, and serum MCP-4 levels were also significantly higher in the BPD group than in the non-BPD group on day 1 [186 pg/ml vs. 128 pg/ml, P < 0.05], day 7 [199 pg/ml vs. 101 pg/ml, P < 0.05], and day 14 [238 pg/ml vs. 106 pg/ml, P < 0.05] of life.Conclusions: Increased levels of Th2 chemokines, eotaxin-2, and MCP-4, are associated with BPD in premature infants. What is Known: • The pathogenesis of BPD is multifactorial and it is difficult to predict and prevent. • Previous studies have demonstrated that inflammation plays a major role in the pathogenesis of BPD. What is New: • Increased Th2 chemokines, eotaxin-2 and MCP-4, were associated with BPD in premature infants. • Abnormal Th1/Th2 response in early life maybe associated with the subsequent development of BPD, which provide a new insight to understand the pathogenesis of the disease.

Ginger ( Zingiber officinale ) prevents severe damage to the lungs due to hyperoxia and inflammation

Background/aim

Hyperoxia- and inflammation-induced lung injury is an important cause of the development of bronchopulmonary dysplasia (BPD) in premature infants. We aimed to ascertain the beneficial effects of ginger ( Zingiber officinale ) on rat pups exposed to hyperoxia and inflammation.

Materials and methods

Thirty-six newborn Wistar rats were randomly divided into 3 groups as the hyperoxia (95% O 2 ) + lipopolysaccharide (LPS) group, the hyperoxia + LPS + ginger-treated group, and the control/no treatment group (21% O 2 ). Pups in the hyperoxia + LPS + ginger group were administered oral ginger at a dose of 1000 mg/kg daily during the study period. Histopathologic, immunochemical (SMA and lamellar body), and biochemical evaluations including total antioxidant status (TAS), total oxidant status (TOS), malondialdehyde (MDA), myeloperoxidase (MPO), tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), interleukin-6 (IL-6), and caspase-3 activities were performed.

Results

Better weight gain and survival rates were shown in the hyperoxia + LPS + ginger group (P < 0.05). In the histopathologic and immunochemical evaluation, severity of lung damage was significantly reduced in the hyperoxia + LPS + ginger group, as well as decreased apoptosis (ELISA for caspase-3) (P < 0.05). Tissue TAS levels were significantly protected, and TOS, MDA, and MPO levels were significantly lower in the hyperoxia + LPS + ginger group (P < 0.05). Tissue TNF-α, IL-1β, and IL-6 concentrations were significantly decreased in the ginger-treated group (P < 0.05).

Conclusion

Ginger efficiently reduced the lung damage and protected the lungs from severe damage due to hyperoxia and inflammation. Therefore, ginger may be an alternative option for the treatment of BPD.

Serum cytokine concentrations, chorioamnionitis and the onset of bronchopulmonary dysplasia in premature infants

OBJECTIVE

To investigate the relationships between serum cytokine concentrations and chorioamnionitis (CAM) and CAM-related bronchopulmonary dysplasia (BPD) in premature infants.

METHODS

Serum was collected at 0 and 7 days after birth from 36 premature infants born at <32 weeks of gestation. We examined the relationships between 30 cytokine concentrations and CAM, BPD, and other perinatal factors.

RESULTS

On day 0, GM-CSF, IL-15, IL-17, IL-2, IL-2R, VEGF, and MIG concentrations were significantly higher in the CAM group (n = 17) than in the non-CAM group (n = 19). These concentrations had decreased by day 7 and were similar in both groups. The IL-12p70 concentration on day 0 was significantly lower in the BPD group (n = 16) than in the non-BPD group (n = 15). BPD incidence was similar between the CAM and non-CAM groups.

CONCLUSIONS

These data support the hypothesis that intrauterine inflammation is not a primary risk factor for BPD. The immunological environment at birth or soon after, rather than intrauterine fetal inflammation (e.g., CAM), is a primary risk factor for BPD onset in preterm infants. Decreased inflammatory responses are particularly relevant, as indicated by the relationship between BPD and low serum IL-12p70 concentrations on day 0.

Is there a potential link between vitamin D and pulmonary morbidities in preterm infants?

BACKGROUND

There hasn't been conclusive proof about the association between vitamin D and pulmonary morbidities of prematurity.

METHODS

106 preterm infants were retrospectively included into this study. Clinical data and blood samples of all the patients were collected within 24 h of admission.

RESULTS

(1) Respiratory distress syndrome (RDS) patients were mainly concentrated in "≤30 weeks" stage when compared with other two gestational age groups. The only significant decrease of vitamin D concentration between RDS and non-RDS patients reflected in "≤30 weeks" stage (RDS vs. non-RDS: 29.48 ± 13.06 vs. 40.47 ± 20.52 nmol/l). (2) Bronchopulmonary dysplasia (BPD) patients were also concentrated in "≤30 weeks" stage. Vitamin D concentration showed significant difference both in "≤30 weeks" stage and "30-34 weeks" stage (≤30 weeks stage, BPD vs. non-BPD: 33.20 ± 16.51 vs. 39.21 ± 16.65 nmol/l; 30-34 weeks stage, BPD vs. non-BPD: 30.36 ± 15.50 vs. 41.21 ± 20.40 nmol/l). (3) Though vitamin D concentration in mechanical ventilation (MV) group was lower than non-MV group, there're no significant differences. (4) Vitamin D concentration in dead cases was significant lower than survival patients at discharge. (5) It showed a good correlation between vitamin D concentration and serum Ca, serum P, duration of MV and duration of oxygen support in "≤30 weeks" stage.

CONCLUSION

The significant decrease of vitamin D concentration between RDS and non-RDS patients only reflected in "≤30 weeks" stage. And significant decrease of vitamin D concentration in BPD patients was both showed in "≤30 weeks" stage and "30-34 weeks" stage, which is consistent with "duration of oxygen support". However, the overall effect did not show any difference in all preterm infants. It seems that the appropriate concentration of vitamin D is beneficial to lung maturation of human. Certainly, large sample, multi-center randomized controlled trials are necessary.

[Association between serum 25(OH)D levels at birth and bronchopulmonary dysplasia in preterm infants]

OBJECTIVE

To assess the association between serum 25-hydroxyvitamin D [25(OH)D] levels at birth and bronchopulmonary dysplasia (BPD) in preterm infants.

METHODS

This study recruited preterm infants with gestational age of below 34 weeks who were born between January 2014 and December 2016. These preterm infants were classified into two groups: BPD and control. The association between serum 25(OH)D levels at birth and BPD was analyzed.

RESULTS

Serum 25(OH)D levels in the BPD group was significantly lower than those in the control group [(37±17 nmol/L vs 47±20 nmol/L; P<0.05), and the rate of vitamin D deficiency was significantly higher than those in the control group (90.2% vs 74.0%; P<0.05). The level of serum 25(OH)D was negatively correlated with the incidence of BPD (r=-0.201, P=0.001).

CONCLUSIONS

Vitamin D deficiency at birth may be associated with BPD in preterm infants, but need to be further studied by multivariate analysis.

Circulating Fibrocytes Are Increased in Neonates with Bronchopulmonary Dysplasia

BACKGROUND

Bronchopulmonary dysplasia (BPD) is characterized by the aberrant remodeling of the lung parenchyma, resulting from accumulation of fibroblasts or myofibroblasts. Circulating fibrocytes are implied in pulmonary fibrosis, but whether these cells are associated with the development of BPD or the progressive fibrosis is unknown. The aim of the present study was to investigate the occurrence of fibrocytes in peripheral venous blood and explore whether these cells might be associated with severity of BPD.

METHODS

We investigated circulating fibrocytes in 66 patients with BPD, 23 patients with acute respiratory distress syndrome(ARDS) and 11 normal subjects. Circulating fibrocytes were defined and quantified as cells positive for CD45 andcollagen-1 by flow cytometry. Furthermore, serum SDF-1/CXCL12 and TGF-β1 were evaluated using ELISA methods. We also investigated the clinical value of fibrocyte counts by comparison with standard clinical parameters.

RESULTS

The patients with BPD had significantly increased numbers of fibrocytes compared to the controls (p < 0.01). Patients with ARDS were not different from healthy control subjects. There was a correlation between the number of fibrocytes and pulmonary hypertension or oxygen saturation (p < 0.05). Fibrocyte numbers were not correlated with other clinical or functional variables or radiologic severity scores. The fibrocyte attractant chemokine CXCL12 increased in plasma (p < 0.05) and was detectable in the bronchoalveolar lavage fluid of 40% of the patients but not in controls.

CONCLUSION

These findings indicate that circulating fibrocytes are increased in patients with BPD and may contribute to pulmonary fibrosis in BPD. Circulating fibrocytes, likely recruited through the CXCR4/CXCL12 axis, might contribute to the production of TGF-β1 for the expansion of fibroblast/myofibroblast population in BPD.

N-Terminal Pro-B Type Natriuretic Peptide as a Marker of Bronchopulmonary Dysplasia or Death in Very Preterm Neonates: A Cohort Study

Background

Bronchopulmonary dysplasia (BPD) is a serious complication of preterm birth. Plasma N-terminal pro-B type natriuretic peptide (NT-proBNP) has been suggested as a marker that may predict BPD within a few days after birth.

Objectives

To investigate the association between NT-proBNP day three and bronchopulmonary dysplasia (BPD) or death and further to assess the impact of patent ductus arteriosus (PDA) on this association in neonates born before 32 gestational weeks.

Methods

A cohort study of 183 neonates born before 32 gestational weeks consecutively admitted to the Neonatal Intensive Care Unit, Aarhus University Hospital, Denmark. On day three plasma samples were collected and echocardiography carried out. NT-proBNP was measured by routine immunoassays. The combined outcome BPD or death was assessed at 36 weeks of postmenstrual age. Receiver operator characteristic (ROC) analysis was performed to determine the discrimination ability of NT-proBNP by the natural log continuous measure to recognize BPD or death. The association of BPD or death was assessed in relation to natural log NT-proBNP levels day three.

Results

The risk of BPD or death increased 1.7-fold with one unit increase of natural log NT-proBNP day three when adjusted for gestational age at birth (OR = 1.7, 95% CI 1.3; 2.3). The association was found both in neonates with and without a PDA. Adjusting for GA, PDA diameter, LA:Ao-ratio, or early onset sepsis did not change the estimate.

Conclusion

We found NT-proBNP to be associated with BPD or death in very preterm neonates. This association was not only explained by the PDA. We speculate that NT-proBNP may help the identification of neonates at risk of BPD as early as postnatal day three.

[FEATURES IMMUNITY IN CHILDREN WITH BRONCHOPULMONARY DYSPLASIA]

The study of the immune system in 131 children with bronchopulmonary dysplasia at the time of remission and exacerbation. Found that children with bronchopulmonary dysplasia inherent low absolute number of lymphocytes, accompanied by increased cytotoxic lymphocytes (CD8, CD 16), oxygendependence ability of granulocytes, and activation of the acute phase of immunoglobulin (IgM), in the absence of clinical signs of exacerbation. In acute respiratory disease, a somewhat paradoxical, cellular immune response with decreased lymphocyte activation against cytotoxic cells. While the dynamics of increase of cytotoxic markers in acute respiratory disease is unsatisfactory, indicating that the depletion of cellular reactivity circuit immunity.

Biological markers in cord blood for prediction of bronchopulmonary dysplasia in premature infants

OBJECTIVE

The current study aims to determine the contents of biological markers in cord blood and to investigate their feasibility as the predictive indices of bronchopulmonary dysplasia (BPD) in premature infants.

MATERIALS AND METHODS

Cord blood was collected from 134 premature infants that had birth weight < or = 1500 g and gestational age (GA) < or = 32 weeks at the time of birth. The contents of IL-6, IL-6R, Sgp130, and MMP-9 were determined. Infants' clinical data, as well as their mothers' placental pathological data were also collected. Infants with BPD constituted the BPD group, whereas those without BPD comprised the non-BPD (NBPD) group. Differences in the contents of the biological markers between the groups were analyzed to investigate the correlations of these markers with BPD, and then biological markers that can serve as the predictive factors of BPD were defined.

RESULTS

GA was negatively correlated with BPD. IL-6, IL-6R, and Sgp130 in the BPD group was higher than those in the NBPD group, whereas MMP-9 in the BPD group was lower than that in the NBPD group. IL-6 was positively correlated with BPD and therefore had a predictive effect on BPD. Sgp130 had a collinear correlation with IL-6, which had a predictive effect on BPD as well. When GA was < 30 weeks and IL-6 was > 46.125 pg/ml, the sensitivity, specificity, and area under curve were 1, 0.59, and 0.849, respectively, indicating a good predictive effect on BPD.

CONCLUSION

IL-6 and Sgp130 can serve as the independent predictive cytokines of BPD.

Cord blood fibroblast growth factor-10 as a possible predictor of bronchopulmonary dysplasia in preterm infants

OBJECTIVE

To evaluate fibroblast growth factor-10 (FGF-10) levels in cord blood as a possible predictor of the subsequent development of bronchopulmonary dysplasia (BPD) in preterm infants.

PATIENTS AND METHODS

A total of 269 preterm (≤32 weeks gestation) infants (76 infants developed BPD and 193 had no BPD) were enrolled. FGF-10 levels were measured by enzyme-linked immunosorbent assay.

RESULTS

Preterm infants who subsequently developed BPD had significantly lower cord serum levels of FGF-10 than those who did not (p < 0.001). Cord blood levels of FGF-10 were significantly lower in infants with severe BPD than those with moderate or mild disease (p < 0.001). Logistic regression analysis demonstrated that low cord blood FGF-10 level was independently associated with the subsequent risk of BPD (OR = 0.978 [95 % CI: 0.959 - 0.997]; p = 0.02).

CONCLUSION

Low cord blood FGF-10 levels may predict the subsequent development of BPD in preterm infants.

Circulating endothelial progenitor cells decrease in infants with bronchopulmonary dysplasia and increase after inhaled nitric oxide

BACKGROUND

Impairment of endothelial progenitor cells (EPCs) has been shown to contribute to the development of bronchopulmonary dysplasia (BPD). In the current study, the relationship between EPC changes of after birth and the development of BPD was investigated, and the effects of inhaled nitric oxide (iNO) on EPCs were evaluated.

METHODS

Sixty infants with a gestational age of less than 32 weeks and a birth weight of less than 1500 g were studied. NO was administered to infants who were receiving mechanical ventilation or CPAP for at least 2 days between the ages of 7 and 21 days. EPC level was determined by flow cytometry at birth, 7, 21 and 28 days of age and 36 weeks' postmenstrual age (PMA), before and after the iNO treatment. Plasma concentrations of vascular endothelial growth factor (VEGF), stromal cell-derived factor-1 and granulocyte-macrophage colony-stimulating factor were determined via immunochemical assay.

RESULTS

Twenty-five neonates developed BPD, 35 neonates survived and did not develop BPD. EPC level was decreased on day 7 and 21 in infants who later developed BPD compared with infants that did not develop BPD. From birth to 21 days of age, BPD infants had a persistently lower VEGF concentration compared with non-BPD infants. No difference was found between the two groups at day 28 or 36 weeks PMA. In infants that later developed BPD, iNO raised the KDR(+)CD133(+) and CD34(+)KDR(+)CD133(+) EPC numbers along with increasing the level of plasma VEGF.

CONCLUSION

EPC level was reduced at 7 days of age in infants with BPD, and iNO increased the EPC number along with increasing the level of VEGF. Further studies are needed to elucidate the mechanism leading to the decrease of EPCs in infants with BPD and to investigate the role of iNO treatment in the prevention of BPD.

Serum selenium levels of the very low birth weight premature newborn infants with bronchopulmonary dysplasia

BACKGROUND

The selenium (Se) is an essential trace element that has a critical role in synthesis and activity of a number of selenoproteins with protective properties against free radical damage. This study was conducted to detect the serum Se concentration in very low birth weight (VLBW) preterm infants and its association with bronchopulmonary dysplasia (BPD).

MATERIALS AND METHODS

Cord blood Se concentration was determined in 54 neonates with gestation age 30 week or less. Another sample was obtained from these infants at day 28 of birth and serum Se levels were measured by atomic absorption spectrophotometer. All neonates were followed for oxygen dependency at 28 day after birth and 36 week postmenstrual age.

RESULTS

The mean cord blood Se concentration in studied neonates was 64.78 ± 20.73 μgL(-1). Serum Se concentration was 60.33 ± 26.62 μgL(-1) at age 28-day. No significant correlation was observed for serum Se concentration at birth and at one month after birth (r = -0.04, p = 0.72). BPD was diagnosed in 25 neonates (46%). The mean serum Se concentration at one month was 57.16 ± 29.68 μgL(-1) in patients with BPD (25 cases) and 63.27 ± 23.6 μgL(-1) in 29 patients without BPD (p = 0.40).

CONCLUSION

In our study, serum Se concentration at 28 day of birth was lower than cord blood levels in preterm neonates, but we have not found significant difference among patients who had BPD or not with respect to serum Se concentrations at this age.

Different subsets of circulating angiogenic cells do not predict bronchopulmonary dysplasia or other diseases of prematurity in preterm infants

Bronchopulmonary dysplasia (BPD) is a chronic lung disease occurring in very and extremely preterm infants undergoing mechanical ventilation. Given the altered lung vascular growth characterizing BPD, circulating angiogenic cells could be useful biomarkers to predict the risk. The objective of the study was to determine whether the percentages of circulating angiogenic cells (CD34+VEGFR-2+, CD34+CD133+VEGFR-2+, and CD45-CD34+CD133+VEGFR-2+ cells), assessed in the peripheral blood at birth by flow cytometry, could be used as markers for the risk of BPD. In one-hundred and forty-two preterm neonates (gestational age less than 32 weeks and/or birth weight less than 1500 g) admitted to our tertiary care Neonatal Intensive Care Unit between 2006 and 2009, we evaluated the percentages of circulating angiogenic cells at birth, at 7 days, and, in a subset of infants (n=40), at 28 days of life. The main outcome was the correlation between cell counts at birth and the subsequent risk of developing BPD. In our study, all the three cell populations failed to predict the development of BPD or other diseases of prematurity. We suggest that these cells cannot be used as biomarkers in preterm infants, and that research is needed to find other early predictors of BPD.

Mean platelet volume in very preterm infants: a predictor of morbidities?

BACKGROUND

Mean platelet volume [MPV] is an important predictor for many diseases and larger platelets are more reactive and associated with shortened bleeding time. Although elevated MPV values are related to respiratory distress syndrome [RDS] in neonates, there are, to our knowledge, no data investigating the relationship between MPV and other diseases of preterm infants.

AIM

To assess the correlation between MPV and the occurrence of various morbidities of prematurity such as necrotizing enterocolitis [NEC], bronchopulmonary dysplasia [BPD], sepsis, retinopathy of prematurity [ROP], and intraventricular hemorrhage [IVH] in a cohort of very preterm infants.

SUBJECTS

We studied infants with a gestational age of < 34 weeks and a birth weight of < 1500 g admitted to a third level Neonatal Intensive Care Unit. Enrolled infants were divided into NEC and non-NEC, sepsis and non-sepsis, ROP and non-ROP, BPD and non-BPD and IVH and non-IVH groups. MPV was evaluated at birth [cord blood] and repeated at 48-72 hours of life.

RESULTS

Two hundred and seventy two infants were studied. MPV measured at birth was similar between sepsis and non-sepsis, and ROP and non-ROP groups. MPV values were higher in infants with BPD [9.08±1.3 fl], IVH [8.4±1.1fl] and NEC [8.6±0.7 f] when compared to the control group [7.6±0.6 fl] in the first day of life.

CONCLUSIONS

High MPV in the first hours of life may reflect the presence of a risk factor for the development of NEC, BPD and IVH in extremely preterm infants. This might be associated with inflammatory and oxidative process. However, our data indicate that higher MPV values are not associated with the development of sepsis or ROP in this study population.        

Plasma lipid metabolites are associated with gestational age but not bronchopulmonary dysplasia

AIM

To test the hypothesis that plasma lipid metabolite levels in premature infants are associated with the development of bronchopulmonary dysplasia (BPD). The studies also tested a secondary hypothesis that plasma lipid metabolite levels were correlated with gestational age.

METHODS

Infants born <32 weeks' gestation were enrolled during the first 72 h of life. Plasma samples were obtained and lipid levels were measured by LC-MS/MS. Clinical data were collected to determine infant outcomes and BPD diagnosis.

RESULTS

Following adjustment for confounders, lipid levels were not associated with BPD; however, levels of specific lipid metabolites were correlated with gestational age.

CONCLUSION

Immature lipid metabolism pathways in premature infants may contribute to the pathogenesis of BPD and other diseases.

[The content of Clara's cells protein in highly premature newborns with respiration disorders]

The study was carried out to analyze the content of Clara's cells protein in highly premature newborns with respiration disorders in neonatal period. The sample of 106 premature newborns of gestational age 26-32 weeks and body mass at birth 660-1500 g was examined. The concentration of Clara's cells protein in bronchoalveolar liquid and blood serum was higher in patients with inborn pneumonia as compared with children with respiratory distress syndrome. The low content Clara's cells protein in highly premature newborns with pneumonia was related with subsequent development of bronchopulmonary dysplasia.

Determination of selenium in serum samples of preterm newborn infants with bronchopulmonary dysplasia using a validated hydride generation system

Bronchopulmonary dysplasia (BPD), also known as chronic lung disease, is one of the most challenging complications in premature newborn infants. Selenium plays a role in antioxidant system by protecting cell membranes and neutralizing the deleterious effects of free radicals. The aim of this study was to determine the relationship between selenium concentration and incidence of bronchopulmonary dysplasia using a validated analytical method. Umbilical cord blood and blood samples 30 days after the birth were collected from 38 preterm newborn infants with gestation age of 32 weeks or less, and the separated serums were kept at -70°C until analysis time. Selenium concentration of serum was determined using an atomic absorption spectrophotometer. The method was validated on the basis of standard validation techniques. The analytical method was linear in the range of 1 to 500 μg/L with the limit of detection of 0.4 μg/L. Samples were collected from 38 infants whose gestation age was 32 weeks or less. The blood samples were collected from the umbilical cord blood at birth in 19 cases. In 25 cases, blood samples were collected 1 month after birth. Of the 15 patients diagnosed with BPD, 10 were boys (p = 0.02). The mean serum selenium concentration was not different at birth between patients with and without BPD, but it was significantly lower at 30 days after birth in patients with BPD (38.5 ± 14.1vs. 45.4 ± 18.7 μg/L, p = 0.02). Preterm newborn infants with BPD had lower serum selenium concentrations 1 month after birth.

Circulating endothelial progenitor cells in premature infants: is there an association with premature birth complications?

BACKGROUND

The most common morbidities in preterm infants are associated with vascular pathology. Endothelial progenitor cells (EPCs) have been implicated in repair of the vasculature, but their role in the pathogenesis of prematurity complications is not clear.

OBJECTIVES

We prospectively investigated an association between the number of EPCs circulating in blood during delivery as well as 2 and 6 weeks afterwards, the level of growth factors regulating their migration/homing, and the incidence of premature birth complications.

PATIENTS AND METHODS

The study groups consisted of 90 preterm and 52 full-term infants. Early-EPCs (CD133+CD34+CD144+) and late-EPCs (CD133-CD34+CD144+) were analysed in cord blood (CB) and peripheral blood (PB).

RESULTS

We found higher early- and late-EPC counts in the CB of premature infants compared with full-term babies. The number of circulating early- and late-EPCs was inversely associated with the Apgar score of preterm infants. A positive association between the early-EPC count and the risk of respiratory distress syndrome, retinopathy of prematurity, bronchopulmonary dysplasia, and infections was found. Nevertheless, multivariate analysis revealed that a higher number of EPCs was not an independent predictor of prematurity complications, which were directly related to lower gestational age. The EPC count in full-term infants maintained a constant, relatively low level over the 6-week follow-up, whereas the EPC population in preterm infants gradually decreased during this period. Furthermore, the number of CB late-EPCs in preterm infants positively correlated with VEGF concentration.

CONCLUSIONS

EPCs may play a considerable role in vascular development in preterm infants.

Respiratory disease and early serum S100A12 changes in very premature infants

AIM

The role of granulocyte-specific S100A12, a marker for inflammatory disorders, in newborn lung disease is unknown. We compared postnatal blood S100A12 concentrations against respiratory distress syndrome (RDS) and bronchopulmonary dysplasia (BPD).

METHODS

Blood samples from 92 newborns were collected on admission, 12 h, day 1, day 3-4 and day 7, and analysed for S100A12. IL-8 and IL-6 were assayed in 52 infants.

RESULTS

Infants with RDS were significantly more premature (median 27 vs. 34 weeks), more likely to receive antenatal corticosteroids (84% vs. 26%) and have lower neutrophil counts (median 2.4 vs. 3.8 × 10(9) /L) at admission. S100A12 levels peaked during the first day and were significantly lower in preterm infants with RDS compared to those without (median 250 vs. 616 ng/mL at 12 h, 281 vs. 828 ng/mL day 1, respectively). S100A12 levels were low among the 35 very preterm infants (24-29 week gestation) regardless of the presence of BPD (285 vs. 288 ng/mL on day 1). In comparison, IL-8 and IL-6 levels were not different between groups.

CONCLUSION

Plasma S100A12 is low in infants with RDS, possibly because of gestationally related differences in neutrophil response or to the effects of antenatal corticosteroids. It is therefore not a useful marker of BPD development.

L-citrulline attenuates arrested alveolar growth and pulmonary hypertension in oxygen-induced lung injury in newborn rats

Bronchopulmonary dysplasia (BPD) is characterized by arrested alveolar development and complicated by pulmonary hypertension (PH). NO promotes alveolar growth. Inhaled NO (iNO) ameliorates the BPD phenotype in experimental models and in some premature infants. Arginosuccinate synthetase (ASS) and arginosuccinate lyase (ASL) convert L-citrulline to L-arginine; L-citrulline is regenerated during NO synthesis from L-arginine. Plasma levels of these NO precursors are low in PH. We hypothesized that L-citrulline prevents experimental O2-induced BPD in newborn rats. Rat pups were assigned from birth through postnatal day (P) 14 to room air (RA), RA + L-citrulline, 95% hyperoxia (BPD model), and 95%O2 + L-citrulline. Rat pups exposed to hyperoxia had fewer and enlarged air spaces and decreased capillary density, mimicking human BPD. This was associated with decreased plasma L-arginine and L-citrulline concentrations on P7. L-citrulline treatment significantly increased plasma L-arginine and L-citrulline concentrations and increased ASL protein expression in hyperoxia. L-citrulline preserved alveolar and vascular growth in O2-exposed pups and decreased pulmonary arterial medial wall thickness (MWT) and right ventricular hypertrophy (RVH). Increased lung arginase (ARG) activity in O2-exposed pups was reversed by L-citrulline treatment. L-citrulline supplementation prevents hyperoxia-induced lung injury and PH in newborn rats. L-citrulline may represent a novel therapeutic alternative to iNO for prevention of BPD.

[Relationship between serum estradiol levels in the early postnatal period and the occurrence of hyaline membrane disease and bronchopulmonary dysplasia in neonates]

OBJECTIVE

This study examined the changes of serum levels of estradiol during the early postnatal period in neonates in order to investigate the possible relationship between the serum estradiol levels and the occurrence of pulmonary hyaline membrane disease (HMD) and bronchopulmonary dysplasia (BPD).

METHODS

Fifty-nine premature infants with the gestational age between 26 and 32 weeks and 61 full-term infants with the gestational ages between 37 and 42 weeks were enrolled. Serum levels of estradiol were measured on postnatal days 1, 3 and 7.

RESULTS

Serum levels of estradiol decreased rapidly after birth in both premature and term infants and there were significant differences among different postnatal ages groups. However, there were no significant differences in the serum estradiol levels between the premature and term groups on postnatal days 1, 3 and 7. Serum estradiol levels measured in premature infants with HMD were not statistically different from those in premature infants without HMD on all time points. Serum estradiol levels in premature infants with BPD were higher than those in premature infants without BPD on postnatal day 3, but there were no noticeable differences on postnatal days 1 and 7.

CONCLUSIONS

Serum estradiol levels decline rapidly within 7 days after birth in both premature and term infants. Serum estradiol levels in the early postnatal period are not associated with the occurrence of HMD and BPD, suggesting that serum estradiol in the early postnatal period can not be used as a marker for predicting the development of HMD and BPD.

Circulating endothelial progenitor cells and diseases of the preterm infant

During the last decade, multiple techniques have been developed to isolate and quantify human endothelial progenitor cells (EPCs). In parallel, a number of studies have applied these methodologies to investigate the number and function of circulating EPCs in adult diseases characterized by vascular dysfunction. However, very little is known about different subtypes of EPCs during gestation, during the neonatal age or in neonatal diseases. Initial evidence supports the hypothesis that circulating angiogenic cells may play an important role during development, and attention has particularly focused in clarifying the function of EPCs in lung vascular development, and the role of the impairment of EPC mobilization and homing in hyperoxia-induced lung injury characteristic of bronchopulmonary dysplasia. Among different subtypes of EPCs, both the role of angiogenic mononuclear cells (triple-positive CD34+CD133+VEGFR-2+ cells and colony forming unit-Hill cells) and endothelial colony forming cells (ECFCs) in physiological vascular development and during neonatal diseases need to be elucidated. A better understanding of EPC biology during gestation, during the neonatal age and in preterm infants will unravel the pathologic basis of bronchopulmonary dysplasia and other preterm and term neonatal diseases characterized by a prominent defect in vascular growth, including retinopathy of prematurity and persistent pulmonary hypertension of the newborn.

Brain-derived neurotrophic factor in infants <32 weeks gestational age: correlation with antenatal factors and postnatal outcomes

Neurotrophins (NTs) play important roles in brain growth and development. Cord blood (CB) brain-derived neurotrophic factor (BDNF) concentrations increase with gestational age but data regarding postnatal changes are limited. We measured BDNF concentrations after birth in 33 preterm infants <32-wk gestation. Serum was collected at birth (CB), at day 2, between day 6 and 10 (D6), at day 30 (D30), and at day 60 (D60). BDNF concentrations fell on D2 (p = 0.03), recovered by D6 (p = 0.10), and continued to rise thereafter at D30 (p = 0.06) and D60 (p = 0.01) compared with CB. CB BDNF concentrations positively correlated with duration of rupture of membranes (r = 0.43, p = 0.04). Antenatal steroids (ANS, p = 0.02), postnatal steroids (PNS, p = 0.04), and retinopathy of prematurity (ROP, p = 0.02) were identified as significant factors in multivariate analyses. The median (25-75th interquartile range) CB BDNF concentrations were higher in infants who received a complete course ANS compared with those who received a partial course [1461 (553-2064) versus 281 (171-536) pg/mL, p = 0.04]. BDNF concentrations negatively correlated with the use of PNS at D30 (r = -0.53, p = 0.002) and at D60 (r = -0.55, p = 0.009). PNS use was associated with reduced concentrations of BDNF at D30 [733 (101-1983) versus 2224 (1677- 4400) pg/mL, p = 0.004] and at D60 [1149 (288-2270) versus 2560 (1337-5166) pg/mL, p = 0.01]. BDNF concentrations on D60 in infants who developed ROP (n = 16) were lower than those who did not develop ROP (n = 7) [1417 (553-2540) versus 3593 (2620-7433) pg/mL, respectively, p = 0.005]. Our data suggests that BDNF concentrations rise beyond the first week of age. BDNF concentrations correlate with factors that influence neurodevelopment outcomes.

MMP-9 and TIMP-1 in the cord blood of premature infants developing BPD

We investigated matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase 1 (TIMP-1) levels in the cord blood of 29 premature infants who were <30 weeks gestation. One, 8, and 14 infants developed severe, moderate and mild bronchopulmonary dysplasia (BPD), respectively, and 6 did not. MMP-9 and TIMP-1 levels in the cord blood were determined by ELISA. MMP-9/TIMP-1 ratios in the cord blood of infants who developed severe or moderate BPD (n = 9) were significantly higher than those who developed mild BPD or did not develop BPD (n = 20; P = 0.015). Multivariate linear regressions demonstrated that MMP-9 levels and MMP-9/TIMP-1 ratios in the cord blood of the premature infants correlated with the oxygen supplementation period (r = 0.58, P = 0.003 and r = 0.41, P = 0.030, respectively). The MMP-9 levels and MMP-9/TIMP-1 ratios correlated with the severity of maternal chorioamnionitis (both trend P = 0.006). The MMP-9 levels and MMP-9/TIMP-1 ratios in the cord blood may be related to the pathogenesis and severity of BPD and maternal chorioamnionitis.

Effect of oestradiol and progesterone replacement on bronchopulmonary dysplasia in extremely preterm infants

OBJECTIVE

To study whether postnatal replacement of oestradiol and progesterone may help to prevent bronchopulmonary dysplasia (BPD).

METHODS

This randomised placebo-controlled double-blind study enrolled 83 infants of <29 weeks gestational age and 1000 g birth weight requiring mechanical ventilation within 12 h after birth. Oestradiol (2.5 mg/kg/day) and progesterone (22.5 mg/kg/day) were given by continuous intravenous infusion of a standard lipid emulsion (15 ml/kg/day) in the replacement group (ESTRA-PRO). The placebo group received the same lipid emulsion without oestradiol or progesterone. A replacement period of at least 2 weeks but not >4 weeks was strived for and defined as "according to protocol". The primary outcome variable was the incidence of BPD or death.

RESULTS

The median birth weight was 670 g (min-max 400-990 g) and the gestational age 25 weeks (23.1-28.1 weeks). The incidence of BPD or death was 48% in the placebo group and 44% in the ESTRA-PRO group (p = 0.38, one-sided testing, intention to treat analysis). In infants treated according to protocol, 32% (9 of 28) in the placebo group and 14% (3 of 21) in the ESTRA-PRO group developed BPD (p = 0.08).

CONCLUSION

Replacement of oestradiol and progesterone was not effective for prevention of BPD or death in extremely preterm born infants. Better-powered trials are needed to evaluate this new approach.

Plasma KL-6 predicts the development and outcome of bronchopulmonary dysplasia

Circulating KL-6 is a specific indicator of pulmonary injury affecting the alveolar epithelium and interstitium. Our preliminary study suggested the usefulness of plasma KL-6 as a marker of bronchopulmonary dysplasia (BPD). To confirm the diagnostic value of KL-6 for BPD as well as to determine the reference range, we conducted a larger prospective study in 135 preterm infants <32 wk GA. Among the infants without oxygen dependence at a postconceptional age of 36 wk, the plasma KL-6 level showed no significant association with GA at any time. Among 42 infants <28 wk GA, plasma KL-6 levels were significantly higher in those with moderate/severe BPD compared with those with no/mild BPD. A plasma level of 199 U/mL at 1 wk or 232 U/mL at 2 wk was an excellent predictor of moderate/severe BPD <28 wk GA (positive predictive value of 83% and 80%, respectively). Unlike nonspecific markers of inflammation or fibrosis, KL-6 objectively reflects the severity of pulmonary injury irrespective of the treatment or the radiographic changes. Therefore, not only as a good marker, measurement of KL-6 may also help to provide new insights into the pathogenesis of BPD.

Elevated Carbon Dioxide Tension as a Predictor of Subsequent Adverse Events in Infants with Bronchopulmonary Dysplasia

Infants with bronchopulmonary dysplasia (BPD) are at risk for numerous complications following discharge from the Neonatal Intensive Care Unit (NICU). Few studies have evaluated risk factors for adverse events (AE). This retrospective study provided an initial evaluation of the use of capillary carbon dioxide (PCO2) tension as a predictor of infants with BPD at increased risk for AE. PCO2 was compared in patients who suffered, or avoided, severe AE, defined as pulmonary hypertension, death, or subsequent reintubation or tracheostomy for respiratory illness. One hundred twelve consecutive patients followed at the BPD clinic were evaluated, and data from 104 subjects were suitable for analysis. Mean PCO2, obtained shortly before or after discharge from NICU, was 47.2 mmHg (range, 31-83). PCO2 was significantly higher in patients who required reintubation and ventilation (54.7 vs. 46.7, p < 0.04). No cutoff value of PCO2 clearly distinguished patients with subsequent AE. PCO2 was not significantly higher in the group of patients who had a severe AE than in the group of patients who did not have a severe AE, but logistic regression showed a significant association between PCO2 and risk of both severe AE (p = 0.018), and readmission to hospital (p = 0.038). An elevated PCO2 is associated with an increased risk of AE, including reintubation, and readmission to hospital, in infants with BPD. Patients with an elevated discharge PCO2 may require closer monitoring during followup. Prospective studies will be needed to confirm these observations.

Effect of dose on response to adrenocorticotropin in extremely low birth weight infants

CONTEXT

Various cosyntropin doses are used to test adrenal function in premature infants, without consensus on appropriate dose or adequate response.

OBJECTIVE

The objective of this study was to test the cortisol response of extremely low birth weight infants to different cosyntropin doses and evaluate whether these doses differentiate between groups of infants with clinical conditions previously associated with differential response to cosyntropin.

DESIGN

The design was a prospective, nested study conducted within a randomized clinical trial of low-dose hydrocortisone from November 1, 2001, to April 30, 2003.

SETTING

The setting was nine newborn intensive care units.

PATIENTS

The patients included infants with 500-999 g birth weight.

INTERVENTION

The drug used was cosyntropin, at 1.0 or 0.1 microg/kg, given between 18 and 28 d of birth.

MAIN OUTCOME MEASURE

We measured the cortisol response to cosyntropin.

RESULTS

Two hundred seventy-six infants were tested. Previous hydrocortisone treatment did not suppress basal or stimulated cortisol values. Cosyntropin, at 1.0 vs. 0.1 microg/kg, yielded higher cortisol values (P < 0.001) and fewer negative responses (2 vs. 21%). The higher dose, but not the lower dose, showed different responses for girls vs. boys (P = 0.02), infants receiving enteral nutrition vs. not (P < 0.001), infants exposed to chorioamnionitis vs. not (P = 0.04), and those receiving mechanical ventilation vs. not (P = 0.02), as well as a positive correlation with fetal growth (P = 0.03). A response curve for the 1.0-microg/kg dose for infants receiving enteral nutrition (proxy for clinically well infants) showed a 10th percentile of 16.96 microg/dl. Infants with responses less than the 10th percentile had more bronchopulmonary dysplasia and longer length of stay.

CONCLUSIONS

A cosyntropin dose of 0.1 microg/kg did not differentiate between groups of infants with clinical conditions that affect response. We recommend 1.0 microg/kg cosyntropin to test adrenal function in these infants.

Retinol-binding protein, transthyretin, and C-reactive protein in extremely low birth weight (ELBW) infants

BACKGROUND

Vitamin A deficiency reduces retinol binding protein (RBP) but not transthyretin (TTR), while inflammation reduces both RBP and TTR and increases C-reactive protein (CRP), an acute phase reactant.

OBJECTIVE

To estimate serum RBP, TTR, and CRP in ELBW infants to test the hypotheses that (a) TTR is a negative acute phase reactant and (b) a higher RBP/TTR ratio or CRP is associated with death/BPD by 36 weeks corrected age.

DESIGN/METHODS

Serum RBP, TTR, and CRP were measured in 79 ELBW infants at 28 days. Area under the curve (AUC) of receiver operating characteristic curve analysis evaluated the predictive value of TTR, the RBP/TTR ratio, and CRP for death/BPD at 36 weeks.

RESULTS

(1) TTR inversely correlated with CRP (r=-0.45, p<0.0001) consistent with TTR being a negative acute phase reactant. (2) The RBP/TTR ratio predicted death/BPD (AUC 0.68 (CI 0.57 to 0.78)). (3) CRP strongly predicted death/BPD (AUC 0.85 (CI 0.76 to 0.92)), even after exclusion of sepsis.

CONCLUSIONS

A higher CRP and RBP/TTR molar ratio on day 28 are associated with death/BPD at 36 weeks in ELBW infants. Lower TTR and maintained RBP/TTR ratios suggest inflammation rather than vitamin A deficiency as the cause for lower serum vitamin A levels in ELBW infants..

Correlation among cytokines, bronchopulmonary dysplasia and modality of ventilation in preterm newborns: improvement with melatonin treatment

Improved survival because of advances in neonatal care has resulted in an increased number of infants at risk for chronic lung disease. Even though the etiology of lung injury is multifactorial, recent animal and clinical data indicate that pulmonary damage depends in large part on the ventilatory strategies used. Ventilator-associated lung injury was believed to result from the use of high pressure, thus, the term barotraumas. This trauma is believed to involve free-radical damage. Oxidant injury is a serious cause of lung injury. In the present study, 110 newborns with respiratory distress syndrome were studied; 55 were treated with melatonin and the other 55 with placebo. All the subjects were mechanically ventilated with or without guaranteed volume. Proinflammatory cytokines [interleukin (IL)-6, IL-8 and tumor necrosis factor (TNF)-alpha] were measured in tracheobronchial aspirate and the clinical outcome was evaluated. Melatonin treatment reduced the proinflammatory cytokines and improved the clinical outcome. The beneficial action of melatonin presumably related to its antioxidative actions.

Plasma and erythrocyte selenium and glutathione peroxidase activity in preterm infants at risk for bronchopulmonary dysplasia

The purpose of this study was to examine the relationships between selenium status, as measured by plasma and erythrocyte selenium and glutathione peroxidase (GPx) activity, and other postnatal factors, including selenium intake, gestational age, and oxygen dependence in preterm infants at risk for bronchopulmonary dysplasia. Eighteen preterm infants of 30 wk gestational age or less were included. At postnatal wk 1 and 4, selenium concentrations and GPx activity were measured and oxygen dependence and daily selenium intakes were determined from the medical chart. Plasma and erythrocyte selenium concentrations decreased from wk 1 to wk 4, whereas erythrocyte GPx activity increased. Increased selenium intakes during wk 1 were associated with increased erythrocyte GPx activity at both time-points, as well as a decreased need for supplemental oxygen on d 28. Preterm infants display increasing erythrocyte GPx activity despite declines in plasma and erythrocyte selenium. GPx activity might be enhanced by very early selenium supplementation.

Low plasma retinol concentrations increase the risk of developing bronchopulmonary dysplasia and long-term respiratory disability in very-low-birth-weight infants

BACKGROUND

The effect of inadequate vitamin A during the neonatal period on lung status is still unknown.

OBJECTIVE

We tested the hypothesis that low plasma retinol concentrations during the first month of life are independently associated with bronchopulmonary dysplasia (BPD) and long-term respiratory morbidity at 6 mo gestationally corrected age (ie, the age the infant would be had the pregnancy gone to term).

DESIGN

Respiratory outcome information was obtained to 6 mo corrected age for a historical cohort of very-low-birth-weight neonates (<1250 g) who were admitted to intensive care over a 7-y period. Neonates with one or more plasma measurements of retinol concentrations < 0.35 micromol/L (<100 microg/L) on days 1-28 were classified as having low vitamin A. BPD was defined at day 28 by clinical and radiologic criteria and by use of supplemental oxygen at 36 wk postmenstrual age (PMA). Dependence on supplemental oxygen was used to identify long-term respiratory disability at 6 mo corrected age. Multivariate logistic regression analyses were conducted.

RESULTS

Of the 350 study infants, 192 (55%) had low vitamin A status. BPD occurred in 52% of survivors at day 28 (173/331) and at 36 wk PMA (147/285). Fourteen percent (33/244) required oxygen support at 6 mo corrected age. Adjusted odds ratios of BPD with low vitamin A were 3.5 (95% CI: 1.7, 7.2) at day 28 and 1.7 (1.0, 2.7) at 36 wk PMA. At 6 mo corrected age, the adjusted odds ratio was 2.6 (1.1, 6.4) for respiratory disability with low vitamin A.

CONCLUSION

Poor vitamin A status during the first month of life significantly increased the risk of developing BPD and long-term respiratory disability.

Successful treatment of acute respiratory distress syndrome and severe pulmonary hypertension in a child with Bordetella pertussis infection

Infection with Bordetella pertussis can cause severe illness with neurological and pulmonary complications in children. Pulmonary hypertension is an early sign of potentially fatal disease and can cause failure of conventional respiratory therapy in severe acute respiratory distress syndrome (ARDS). We report a 4 1/2-year-old boy with B. pertussis infection who developed severe ARDS and pulmonary hypertension. Because of severe neurological signs the patient did not qualify for extracorporal membrane oxygenation (ECMO). After conventional ventilation, surfactant and high frequency oscillation ventilation (HFOV) failed, treatment with nitric oxide (NO) improved oxygenation, allowing recovery without the need for ECMO. The patient survived with few sequelae. Thus, this treatment may be an option in high-risk children who meet the criteria for ECMO but are excluded because of poor neurological status, as in our patient.

Vitamin A and Bronchopulmonary Dysplasia: Research, Issues, and Clinical Practice

Vitamin A is a crucial antioxidant for preterm infants because it protects the lungs from oxidative damage induced by the administration of supplemental oxygen. Although all preterm infants are born with smaller vitamin A stores than full-term infants, the store of vitamin A in preterm infants at risk for bronchopulmonary dysplasia (BPD) is often especially deficient. Despite the increases in plasma vitamin A concentrations that have been achieved with vitamin A supplementation, only modest improvements in clinical outcomes and incidence of BPD have been noted in this population. This article reviews the research on vitamin A supplementation for preterm infants, as well as the issues and clinical implications associated with this intervention.

Coagulase-negative staphylococcal sepsis as a predictor of bronchopulmonary dysplasia

AIM

To determine whether sepsis caused by coagulase-negative staphylococci (CoNS) is a risk factor for developing bronchopulmonary dysplasia (BPD) in premature newborns.

METHODS

All newborns born at < or = 30 wk of gestation at Orebro University Hospital during 1994-2001 with clinical sepsis caused by CoNS (group A, n = 22) or by other bacteria (group B, n = 17) were included and compared with premature newborns without sepsis (group C, n = 53). Clinical sepsis was defined as a positive blood culture (monoculture) plus clinical symptoms and laboratory findings. BPD was defined as treatment with oxygen > 21% for at least 28 d.

RESULTS

The incidence of BPD differed between the three groups, as follows: CoNS sepsis (A) 64%, other sepsis (B) 41% and control (C) 24%. The difference between the control group and the sepsis groups was highly significant (p = 0.006). In a univariate model the crude estimates of relative risk (RR) for occurrence of BPD increased with presence of sepsis and particularly with presence of sepsis with CoNS (A: RR 2.6, 95% CI 1.5-4.6, p = 0.001; B: RR 1.7, CI 0.8-3.5, p = 0.17). When regression was performed with two additional predictive variables in multivariate models including sepsis, gestational age and mechanical ventilation (group A: RR 1.5, CI 1.1-2.0, p = 0.004; group B: RR 0.9, CI 0.6-1.4, p = 0.67), the estimates were lower.

CONCLUSION

The relative risk for BPD is significantly increased in premature newborns with sepsis caused by CoNS compared with those with sepsis caused by other bacteria and compared with premature newborns with no sepsis.

Inflammatory markers in intrauterine and fetal blood and cerebrospinal fluid compartments are associated with adverse pulmonary and neurologic outcomes in preterm infants

Recent evidence strongly implicates the inflammatory response to intrauterine infection in the pathogenesis of neonatal brain and lung injury. We hypothesized that lung and brain injury in preterm infants occurs during a common developmental window of vulnerability as the result of an inflammatory response in different compartments. To determine whether inflammatory markers in these compartments are associated with bronchopulmonary dysplasia (BPD) or cranial ultrasound (CUS) abnormalities in infants <33 wk gestation age (GA) and <1501 g birth weight, we analyzed placental pathology and serum and cerebrospinal fluid (CSF) IL-6, IL-1beta, and tumor necrosis factor-alpha (TNF-alpha) concentrations in 276 infants. Logistic regressions were performed stratified by GA. Histologic chorioamnionitis was significantly associated with BPD in infants </=28 wk GA (OR 3.6, p = 0.027). Maternal stage of chorioamnionitis significantly correlated with severity of BPD. Presence of a fetal inflammatory response indicated by fetal vasculitis or elevated cytokines was not associated with the development of BPD. Serum IL-6 >/=17 pg/mL was associated with an abnormal CUS in infants >28 wk GA (OR 3.36, p = 0.023) but not </=28 wk GA. CSF concentrations of IL-6 >/=6.5 pg/mL and TNF-alpha >/=3 pg/mL were associated with abnormal CUS in infants </=28 wk GA (IL-6 OR 3.0; TNF-alpha OR 3.5; p < 0.05 each case) but not >/=28 wk GA. These data suggest that in infants </=28 wks GA, BPD may be initiated by inflammatory mediators in amniotic fluid, but brain injury may involve variations in the systemic inflammatory response.

MMP-2 and MMP-9 and their tissue inhibitors in the plasma of preterm and term neonates

Matrix metalloproteinases (MMP) and their tissue inhibitors (TIMP) are involved in a variety of physiologic growth and development and pathophysiologic inflammatory conditions. We hypothesized that 1) MMP-2 and -9 plasma activities and TIMP-1 and -2 plasma concentrations in preterm and term neonates were dependent on the gestational and postnatal age; and 2) the respective MMP and their inhibitors were deranged in the development of bronchopulmonary dysplasia (BPD) and intraventricular hemorrhage (IVH) in preterm neonates. From 1998 to 1999, blood samples were collected from preterm neonates (25-36 wk gestation) with or without BPD and/or IVH as well as from healthy term (37-40 wk gestation) neonates during the first 28 d of life. MMP-2 and MMP-9 plasma activities were measured by zymography; TIMP-1 and TIMP-2 plasma concentrations were determined by ELISA. In neonates without BPD or IVH (n = 50), MMP-2 and MMP-9 plasma activities both appeared to be gestational age dependent, with the highest levels observed in neonates of 33-36 wk gestation. TIMP-1 plasma concentration was highest in term neonates but no gestational difference was found in TIMP-2. Only MMP-9 showed a 50% decrease after d 1 in the first postnatal month. Twelve preterm infants with BPD and/or IVH had significantly lower MMP-2 but higher MMP-9 activity and higher TIMP-1 concentration than those of corresponding neonates without BPD or IVH. These findings show the gestational age-dependent expression of plasma MMP activities and their inhibitors. MMP and TIMP may be involved in the feto-neonatal development and may contribute to the pathogenesis of BPD and/or IVH in critically ill preterm neonates.

Plasma Arginine and Urinary Nitrate and Nitrite Excretion in Bronchopulmonary Dysplasia

The aim of this prospective study was to determine whether preterm infants with bronchopulmonary dysplasia (BPD) and signs of increased pulmonary artery pressure have a deficiency of plasma arginine (ARG) and systemic nitric oxide (NO) synthesis. Plasma amino acid concentrations, Doppler pulmonary systolic time intervals (ratio of acceleration time and ejection time corrected for heart rate: AT/ET(C)) and urinary nitrate and nitrite concentrations were determined at the 28th day postnatal age and at 36 weeks postmenstrual age in 73 preterm infants less than 30 weeks gestational age. The AT/ET(C) ratios were significantly lower in infants with BPD (n = 32) compared to controls. However, total amino acid concentrations, ARG intake as well as plasma ARG concentrations were not different between groups (median (interquartile-range) micromol/l): control: 58 (42.5-75.5) and 54.5 (42-71) at day 28 and 36 weeks; BPD: 54.5 (31.5-70.5) and 43 (35-62), respectively. Urinary nitrate and nitrite concentrations, were not different between groups at day 28, but significantly higher in infants with BPD at 36 weeks (p = 0.014). In conclusion, plasma ARG concentrations and systemic NO synthesis were not deficient in preterm infants with BPD and signs of elevated pulmonary artery pressure.

Growth and adrenal androgen status at 7 years in very low birth weight survivors with and without bronchopulmonary dysplasia

AIMS

To evaluate whether 7 year old VLBW (very low birth weight, <1500 g) survivors with and without bronchopulmonary dysplasia (BPD) evince similar growth status and higher adrenal androgen (AA) levels than term controls, and whether AA levels are higher in VLBW children born small for gestational age (SGA) than in non-SGA cases.

METHODS

Assessment of height standard deviation score (SDs), body mass index (BMI), and serum androstenedione and dehydroepiandrostenedione sulphate levels in 31 VLBW children with BPD, 33 without BPD (no-BPD group), and 33 term controls.

RESULTS

Lower median (range) height SDs was found in BPD (-1.0 (-3.4 to 1.4) SD) and no-BPD (-0.9 (-2.9 to 2.2) SD) children than in term controls (0.3 (-1.5 to 1.9) SD). Low BMI (below 10th centile) was more common in both the BPD (18 (58%)) and no-BPD (16 (49%)) children compared to term cases (3 (9%)). The median (range) androstenedione levels tended to be higher in the BPD (0.8 (0 to 2.8) nmol/l) and no-BPD (0.8 (0 to 2.3) nmol/l) groups than in term controls (0.6 (0 to 1.8)). Higher median (range) dehydroepiandrostenedione sulphate levels were detected in the no-BPD compared to the term group (0.9 (0 to 4.1) v 0.3 (0 to 2.3) micro mol/l). VLBW children born SGA had higher AA levels compared to non-SGA cases.

CONCLUSIONS

At 7 years of age, VLBW children are shorter and tend to have higher AA levels than term controls, but VLBW children with and without BPD do not differ from each other in growth or AA status. Those born SGA have higher AA levels compared to non-SGA cases. The consequences of these findings to final height and to later metabolic and vascular health remain to be determined.

Neutrophil and monocyte adhesion molecules in bronchopulmonary dysplasia, and effects of corticosteroids

AIMS

To study a longitudinal change in the expression of adhesion molecules CD11b, CD18, and CD62L on neutrophils and monocytes in very low birth weight babies who develop respiratory distress syndrome, to compare these levels between bronchopulmonary dysplasia (BPD) and non-BPD infants, and to assess the effect of corticosteroid treatment on these adhesion molecules.

METHODS

Of 40 eligible neonates, 11 neonates were oxygen dependent at 36 weeks (BPD 36 weeks), 16 infants were oxygen dependent at 28 days, but not at 36 weeks (BPD d28), and 13 infants did not develop BPD. Seventeen neonates received a six day course of steroid treatment. Expression of CD11b, CD18, and CD62L was measured on neutrophils and monocytes in arterial blood on days 1, 3, 7, 14, 21, and 28, and before and 2-3 days after initiation of dexamethasone treatment by flow cytometry.

RESULTS

CD18 expression on neutrophils and monocytes and CD62L on neutrophils, measured as mean fluorescent intensity, was significantly decreased in BPD neonates compared to non-BPD neonates on days 1-28. Dexamethasone treatment significantly decreased CD11b, CD18, and CD62L expression on neutrophils, and CD11b and CD18L expression on monocytes.

CONCLUSIONS

Decreased CD18 expression on neutrophils and monocytes, and decreased CD62L expression on neutrophils, measured as mean fluorescent intensity during the first four weeks of life in micropremies may be risk factors and early predictors of BPD. Dexamethasone use was associated with decreased expression of CD11b, CD18, and CD62L.