Increased interleukin-8 and monocyte chemoattractant protein-1 concentrations in mechanically ventilated preterm infants with pulmonary hemorrhage

Recombinant adiponectin protects the newborn rat lung from lipopolysaccharide-induced inflammatory injury

Preterm infants are at high risk for developing bronchopulmonary dysplasia and pulmonary hypertension from inflammatory lung injury. In adult models, adiponectin (APN)—an adipocyte‐derived hormone—protects the lung from inflammatory injury and pulmonary vascular remodeling. Cord blood APN levels in premature infants born < 26 weeks gestation are 5% of the level in infants born at term. We previously reported the expression profile of APN and its receptors in neonatal rat lung homogenates during the first 3 weeks of postnatal development. Here, we characterize the expression profile of APN and its receptors in specific lung cells and the effects of exogenous recombinant APN (rAPN) on lipopolysaccharide‐(LPS)‐induced cytokine and chemokine production in total lung homogenates and specific lung cells. In vitro, rAPN added to primary cultures of pulmonary artery smooth muscle cells attenuated the expression of LPS‐induced pro‐inflammatory cytokines while increasing the expression of anti‐inflammatory cytokines. In vivo, intraperitoneal rAPN (2 mg/kg), given 4 hr prior to intrapharyngeal administration of LPS (5 mg/kg) to newborn rats at postnatal day 4, significantly reduced gene and protein expression of the pro‐inflammatory cytokine IL‐1ß and reduced protein expression of the chemokines monocyte chemoattractant protein (MCP‐1) and macrophage inflammatory protein‐1 alpha (MIP‐1α) in the lung. LPS‐induced histopathological changes in the lung were also decreased. Moreover, rAPN given 20 hr after intrapharyngeal LPS had a similar effect on lung inflammation. These findings suggest a role for APN in protecting the lung from inflammation during early stages of lung development.

Halogen exposure injury in the developing lung

Owing to a high-volume industrial usage of the halogens chlorine (Cl₂ ) and bromine (Br₂ ), they are stored and transported in abundance, creating a risk for accidental or malicious release to human populations. Despite extensive efforts to understand the mechanisms of toxicity upon halogen exposure and to develop specific treatments that could be used to treat exposed individuals or large populations, until recently, there has been little to no effort to determine whether there are specific features and or the mechanisms of halogen exposure injury in newborns or children. We established a model of neonatal halogen exposure and published our initial findings. In this review, we aim to contrast and compare the findings in neonatal mice exposed to Br₂ with the findings published on adult mice exposed to Br₂ and the neonatal murine models of bronchopulmonary dysplasia. Despite remarkable similarities across these models in overall alveolar architecture, there are distinct functional and apparent mechanistic differences that are characteristic of each model. Understanding the mechanistic and functional features that are characteristic of the injury process in neonatal mice exposed to halogens will allow us to develop countermeasures that are appropriate for, and effective in, this unique population.

Human amnion cells reverse acute and chronic pulmonary damage in experimental neonatal lung injury

Background

Despite advances in neonatal care, bronchopulmonary dysplasia (BPD) remains a significant contributor to infant mortality and morbidity. While human amnion epithelial cells (hAECs) have shown promise in small and large animal models of BPD, there is scarce information on long-term benefit and clinically relevant questions surrounding administration strategy remain unanswered. In assessing the therapeutic potential of hAECs, we investigated the impact of cell dosage, administration routes and timing of treatment in a pre-clinical model of BPD.

Methods

Lipopolysaccharide was introduced intra-amniotically at day 16 of pregnancy prior to exposure to 65% oxygen (hyperoxia) at birth. hAECs were administered either 12 hours (early) or 4 days (late) after hyperoxia commenced. Collective lung tissues were subjected to histological analysis, multikine ELISA for inflammatory cytokines, FACS for immune cell populations and 3D lung stem cell culture at neonatal stage (postnatal day 7 and 14). Invasive lung function test and echocardiography were applied at 6 and 10 weeks of age.

Results

hAECs improved the tissue-to-airspace ratio and septal crest density in a dose-dependent manner, regardless of administration route. Early administration of hAECs, coinciding with the commencement of postnatal hyperoxia, was associated with reduced macrophages, dendritic cells and natural killer cells. This was not the case if hAECs were administered when lung injury was established. Fittingly, early hAEC treatment was more efficacious in reducing interleukin-1β, tumour necrosis factor alpha and monocyte chemoattractant protein-1 levels. Early hAEC treatment was also associated with reduced airway hyper-responsiveness and normalisation of pressure–volume loops. Pulmonary hypertension and right ventricle hypertrophy were also prevented in the early hAEC treatment group, and this persisted until 10 weeks of age.

Conclusions

Early hAEC treatment appears to be advantageous over late treatment. There was no difference in efficacy between intravenous and intratracheal administration. The benefits of hAEC administration resulted in long-term improvements in cardiorespiratory function.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-017-0689-9) contains supplementary material, which is available to authorized users.

Blood Cytokine Profiles Associated with Distinct Patterns of Bronchopulmonary Dysplasia among Extremely Low Birth Weight Infants

OBJECTIVE

To explore differences in blood cytokine profiles among distinct bronchopulmonary dysplasia (BPD) patterns.

STUDY DESIGN

We evaluated blood spots collected from 943 infants born at ≤1000 g and surviving to 28 days on postnatal days 1, 3, 7, 14, and 21 for 25 cytokines. Infants were assigned to the following lung disease patterns: (1) no lung disease (NLD); (2) respiratory distress syndrome without BPD; (3) classic BPD (persistent exposure to supplemental oxygen until 28 days of age); or (4) atypical BPD (period without supplemental oxygen before 28 days). Median cytokine levels for infants with BPD were compared with the IQR of results among infants with NLD.

RESULTS

The distribution of enrolled infants by group was as follows: 69 (NLD), 73 (respiratory distress syndrome), 381 (classic BPD), and 160 (atypical BPD). The remaining 260 infants could not be classified because of missing data (104) or not fitting a predefined pattern (156). Median levels of 3 cytokines (elevated interleukin [IL]-8, matrix metalloproteinase-9; decreased granulocyte macrophage colony-stimulating factor) fell outside the IQR for at least 2 time points in both infants with atypical and classic BPD. Profiles of 7 cytokines (IL-6, IL-10, IL-18, macrophage inflammatory protein-1α, C-reactive protein, brain-derived neurotrophic factor, regulated on activation, normal T cell expressed and secreted) differed between infants with classic and atypical BPD.

CONCLUSIONS

Blood cytokine profiles may differ between infants developing classic and atypical BPD. These dissimilarities suggest the possibility that differing mechanisms could explain the varied patterns of pathophysiology of lung disease in extremely premature infants.

Inhalable tranexamic acid for haemoptysis treatment

PURPOSE

An inhalable dry powder formulation of tranexamic acid (TA) was developed and tested in a novel high-dose Orbital® multi-breath inhaler. The formulation was specifically intended for the treatment of pulmonary haemorrhage and wound healing associated with haemoptysis.

METHODS

Inhalable TA particles were prepared by spray drying and the powder characterised using laser diffraction, electron microscopy, thermal analysis, moisture sorption and X-ray powder diffraction. The aerosol performance was evaluated using cascade impaction and inline laser diffraction and interaction with epithelia cells and wound healing capacity investigated using Calu-3 air interface model.

RESULTS

The spray dried TA particles were crystalline and spherical with a D0.5 of 3.35 μm. The powders were stable and had limited moisture sorption (0.307%w/w at 90%RH). The Orbital device delivered ca. 38 mg powder per 'inhalation' at 60 l · min(-1) across four sequential shots with an overall fine particle fraction (⩽ 6.4 μm) of 59.3 ± 3.5% based on the emitted mass of ca. 150 mg. The TA particles were well tolerated by Calu-3 bronchial epithelia cells across a wide range of doses (from 1 nM to 10nM) and no increase in inflammatory mediators was observed after deposition of the particles (a decrease in IL-1β, IL-8 and INFγ was observed). Time lapse microscopy of a damaged confluent epithelia indicated that wound closure was significantly greater in TA treated cells compared to control.

CONCLUSION

A stable, high performance aerosol of TA has been developed in a multi-breath DPI device that can be used for the treatment of pulmonary lesions and haemoptysis.

The effects of gas humidification with high-flow nasal cannula on cultured human airway epithelial cells

Humidification of inspired gas is important for patients receiving respiratory support. High-flow nasal cannula (HFNC) effectively provides temperature and humidity-controlled gas to the airway. We hypothesized that various levels of gas humidification would have differential effects on airway epithelial monolayers. Calu-3 monolayers were placed in environmental chambers at 37°C with relative humidity (RH) < 20% (dry), 69% (noninterventional comparator), and >90% (HFNC) for 4 and 8 hours with 10 L/min of room air. At 4 and 8 hours, cell viability and transepithelial resistance measurements were performed, apical surface fluid was collected and assayed for indices of cell inflammation and function, and cells were harvested for histology (n = 6/condition). Transepithelial resistance and cell viability decreased over time (P < 0.001) between HFNC and dry groups (P < 0.001). Total protein secretion increased at 8 hours in the dry group (P < 0.001). Secretion of interleukin (IL)-6 and IL-8 in the dry group was greater than the other groups at 8 hours (P < 0.001). Histological analysis showed increasing injury over time for the dry group. These data demonstrate that exposure to low humidity results in reduced epithelial cell function and increased inflammation.

Circulating beta chemokine and MMP 9 as markers of oxidative injury in extremely low birth weight infants

Matrix metalloproteinases (MMPs) and chemokines seem to be induced by hyperoxia in preclinical studies. We hypothesized that O2 exposure immediately after birth is associated with altered blood spot MMP 9 and beta chemokine concentrations. The following analytes were measured on blood spots on d 1 and 3 of life, using luminex technology in 1059 infants (birth weights <1000 g) in the NICHD Neonatal Research Network: MMP 9, monocyte chemoattractant protein 1 (MCP 1), macrophage inflammatory proteins (1alpha and beta), and regulated upon activation, normal t cell expressed and secreted (RANTES). Infants administered O2 continually from 6 to 24 h of life (n = 729), when compared with those with <6 h exposure (n = 330), had significantly lower mean birth weight and higher rate of respiratory distress syndrome (p < 0.002). On d 3, MCP 1 was higher and RANTES lower among infants with early prolonged O2 exposure. After adjusting for covariates, prolonged early O2 exposure retained a statistically significant association with higher MCP 1 on d 3 (p = 0.003). The consistent association between O2 exposure and MCP 1 among extremely preterm infants suggests that further investigation of its role in oxidative injury is warranted.

Effects of oxygen concentration and exposure time on cultured human airway epithelial cells

OBJECTIVES

To distinguish the direct effects of oxygen dose and exposure time on human airway epithelial cells. We hypothesized that progressive oxygen exposure would induce cell dysfunction and inflammation in a dose-dependent manner.

DESIGN

Interventional laboratory study.

SETTING

An academic medical research facility in the northeastern United States.

SUBJECTS

Calu-3 human airway epithelial cell culture.

INTERVENTIONS

Cells were cultured at a gas-liquid interface with the cells fed basolaterally with medium and grown to full confluence. The apical surfaces were then exposed to gas containing 21%, 40%, 60%, or 80% oxygen, 5% CO2, and balance nitrogen for 24 or 72 hrs.

MEASUREMENTS AND MAIN RESULTS

The effects of oxygen concentration and time-induced cellular change were examined by measuring transepithelial resistance of monolayers, cell viability by trypan blue exclusion, basolateral lactate concentration, histology of monolayer cross-sections, and cytospin slides, plus interleukin (IL)-6 and IL-8 secretion in apical surface fluid. Transepithelial resistance decreased in a dose- and time-dependent manner (p < .001), whereas cell viability was reduced only at 72 hrs and in all hyperoxic groups (p < .05). IL-6 secretion was elevated in all hyperoxic groups at 24 hrs (p < .001), and both IL-6 and IL-8 levels were greater in the 40% FiO2 group compared with all other groups at 72 hrs (p < .01).

CONCLUSIONS

In this model, airway epithelial cells demonstrate profound concentration and time-dependent responses to hyperoxic exposure with respect to cell physiology, viability, histology, and secretion of inflammatory mediators. This model might be a valuable tool for preliminary analysis of potentially protective therapies against hyperoxia-induced airway epithelial injury.

Intrauterine neutrophil activation is associated with pulmonary haemorrhage in preterm infants

BACKGROUND

Clinical and experimental studies showing lung damage associated with biologically active neutrophil derivatives suggests the possibility that intrauterine neutrophil activation may predispose to the development of pulmonary haemorrhage in extremely low birthweight infants early after birth.

OBJECTIVES

To assess neutrophil functional activity in cord blood from extremely low birthweight infants who subsequently developed severe pulmonary haemorrhage.

METHODS

Neutrophil functional activity was evaluated in the cord blood of preterm neonates (gestational age <28 weeks and weight <800 g) who developed pulmonary haemorrhage (n = 6) and in controls who did not (n = 6). Infants with congenital abnormalities and noteworthy maternal complications such as diabetes, pre-eclampsia, haemorrhagic disorders, and connective tissue disease were excluded. Neutrophils isolated from cord blood immediately after delivery were tested to evaluate neutrophil chemotaxis, random motility, and chemiluminescence. Standard methodology was used.

RESULTS

Chemotaxis and chemiluminescence of neutrophils from cord blood of infants with pulmonary haemorrhage was higher than in the controls (34.8 (2.0) v 28.6 (0.8) microm, p<0.001, and 95.8 (8.5) v 73.2 (3.6) cpm x10(3), p<0.001 respectively). Random motility of cord blood neutrophils was comparable in the two groups (28.6 (1.2) v 25.3 (1.2) microm, p<0.09).

CONCLUSIONS

Intrauterine induction of chemotactic activity and metabolic oxygenation of neutrophils may predispose to the development of pulmonary haemorrhage in extremely low birthweight infants with respiratory distress early after birth.

Delayed extubation to nasal continuous positive airway pressure in the immature baboon model of bronchopulmonary dysplasia: lung clinical and pathological findings

OBJECTIVE

Using the 125-day baboon model of bronchopulmonary dysplasia treated with prenatal steroid and exogenous surfactant, we hypothesized that a delay of extubation from low tidal volume positive pressure ventilation to nasal continuous positive airway pressure at 5 days (delayed nasal continuous positive airway pressure group) would not induce more lung injury when compared with baboons aggressively weaned to nasal continuous positive airway pressure at 24 hours (early nasal continuous positive airway pressure group), because both received positive pressure ventilation.

METHODS AND RESULTS

After delivery by cesarean section at 125 days (term: 185 days), infants received 2 doses of Curosurf (Chiesi Farmaceutica S.p.A., Parma, Italy) and daily caffeine citrate. The delay in extubation to 5 days resulted in baboons in the delayed nasal continuous positive airway pressure group having a lower arterial to alveolar oxygen ratio, high PaCO2, and worse respiratory function. The animals in the delayed nasal continuous positive airway pressure group exhibited a poor respiratory drive that contributed to more reintubations and time on mechanical ventilation. A few animals in both groups developed necrotizing enterocolitis and/or sepsis, but infectious pneumonias were not documented. Cellular bronchiolitis and peribronchiolar alveolar wall thickening were more frequently seen in the delayed nasal continuous positive airway pressure group. Bronchoalveolar lavage levels of interleukin-6, interleukin-8, monocyte chemotactic protein-1, macrophage inflammatory protein-1 alpha, and growth-regulated oncogene-alpha were significantly increased in the delayed nasal continuous positive airway pressure group. Standard and digital morphometric analyses showed no significant differences in internal surface area and nodal measurements between the groups. Platelet endothelial cell adhesion molecule vascular staining was not significantly different between the 2 nasal continuous positive airway pressure groups.

CONCLUSIONS

Volutrauma and/or low-grade colonization of airways secondary to increased reintubations and ventilation times are speculated to play causative roles in the delayed nasal continuous positive airway pressure group findings.

IL-10, IL-6 and CD14 polymorphisms and sepsis outcome in ventilated very low birth weight infants

BACKGROUND

Genetic variation in the innate immune system of the host may play a role in determining the risk of developing infection, as well as outcome from infection.

METHODS

Infectious complications were retrospectively determined in 293 (233 African-American (AA), 57 Caucasian and 3 Hispanic) mechanically ventilated very low birth weight (VLBW) infants (<1500 grams at birth) who were genotyped for the IL-6 -174 G/C, IL-10 -1082 G/A and CD14 -260 C/T single nucleotide polymorphisms (SNPs).

RESULTS

The IL-6 -174C allele was associated with an increased incidence of late blood stream infection (BSI) in AA but not Caucasian infants. In AA infants with the C allele the incidence of late BSI was 20/29 (69%) compared to 94/204 (46%) in homozygous GG infants (RR 2.6, 95% CI: 1.1-6.0, p = 0.021). The IL-10 -1082A allele was associated with an increased incidence of late BSI. One or more episodes of late BSI developed in 14 (35%) of 40 infants with the GG genotype, 71 (49%) of 145 infants with the GA genotype and 63 (58%) of 108 infants with the AA genotype (p = 0.036). Infants with the A allele (AA or GA genotypes) had an incidence of late BSI that was 134/253 (53%) compared to 14/40 (35%) in homozygous GG infants (RR 2.1, 95% CI: 1.04-4.19, p = 0.035). The CD14 -260 C/T SNP did not alter the overall risk for BSI in ventilated VLBW infants. Multiple BSI episodes were more common in the TT genotype group (CC: 17%, CT: 11%, TT: 30%, p = 0.022). This effect was due to the strong effect of the TT genotype on the incidence of multiple BSI in AA infants (CC: 15%, CT: 11%, TT: 39%, p = 0.003).

CONCLUSION

The IL-6 -174 G/C, IL-10 -1082 G/A and CD14 -260 C/T SNPs may alter risk for BSI in ventilated VLBW infants.

Patent Ductus Arteriosus and Respiratory Outcome in Premature Infants

A persistent ductus arteriosus is a common event in preterm infants. The systemic-to-pulmonary shunting that occurs as the pulmonary vascular resistance decreases after birth can have significant cardiovascular and respiratory consequences. Acute pulmonary effects include pulmonary edema and hemorrhage, worsened lung mechanics and deterioration in gas exchange with hypoxemia and hypercapnia. The increased pulmonary blood flow can also produce damage to the capillary endothelium and trigger an inflammatory cascade. This, plus the need for longer and more aggressive mechanical ventilation, can explain the association between patent ductus arteriosus and an increased risk for bronchopulmonary dysplasia in extremely premature infants.

Interleukin-10 -1082 G/A polymorphism and risk of death or bronchopulmonary dysplasia in ventilated very low birth weight infants

IL-10 is an anti-inflammatory cytokine that may have a protective role in acute lung injury. IL-10 expression is affected by a single-nucleotide polymorphism (SNP) located at position -1082 (G to A). The A allele is associated with lower IL-10 production. Low IL-10 production has been linked to the development of BPD. Thus, the IL-10 -1082 SNP may be a genetic risk factor for the development of BPD in the premature newborn. The IL-10 -1082 SNP was determined in 294 (235 African American, 56 Caucasian, and 3 Hispanic) mechanically ventilated very low birth weight (VLBW) infants and compared to outcome (death and/or development of BPD). Differences in groups were analyzed using ANOVA (continuous variables) or chi square (proportions). The frequency of the A allele in our population was 0.62. Thirty-nine (13.3%) infants were homozygous GG, 146 (49.7%) were heterozygous GA, and 109 (37.0%) were homozygous AA. There were no significant differences between genotype groups with respect to ethnic origin, gender, need for surfactant replacement therapy, and isolation of Ureaplasma urealyticum or Mycoplasma hominis from tracheal aspirates at birth. However, AA infants were slightly more mature and of greater birth weight than GA infants (26.9 +/- 0.2 weeks vs. 26.3 +/- 0.2 weeks, P < 0.05, and 940 +/- 22 g vs. 882 +/- 18 g, P < 0.05, respectively). There was no significant effect of the IL-10 -1082 SNP on mortality or the development of BPD (O2 on 28 days or 36 weeks postconceptional age). However, when considered together, the IL-10 -1082 AA/GA genotypes (lower IL-10 production) were associated with a trend toward reduction in risk for the combined outcome of BPD or death (18/39 vs. 80/255, respectively; P = 0.068). The incidence of other complications of prematurity (retinopathy of prematurity, intraventricular hemorrhage, or periventricular leukomalacia) was not different between groups. In conclusion, the IL-10 -1082 G/A SNP does not have a major influence on mortality or the development of BPD in ventilated VLBW infants.

Angiotensin converting enzyme insertion/deletion polymorphism does not alter sepsis outcome in ventilated very low birth weight infants

OBJECTIVE

This study compared the effect of the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphisms on the incidence and outcome of sepsis in ventilated very low birth weight infants.

STUDY DESIGN

Infectious complications were retrospectively determined in 295 (234 African-American, 58 Caucasian and three Hispanic) mechanically ventilated very low birth weight (VLBW) infants (<1500 g at birth) and compared ACE I/D genotype.

RESULTS

The incidence of the D allele in the study population was 0.60. A total of 113 (38.3%) infants were homozygous DD, 128 (43.4%) were heterozygous ID and 54 (18.3%) were homozygous II. One or more episodes of late BSI developed in 28 (52%) of 54 infants with the II genotype, 66 (52%) of 128 infants with the ID genotype and 52 (46%) of 113 infants with the DD genotype (p=0.618). Neither the rates of non-CONS BSI (II: 24%, ID: 23%, DD: 22%; p=0.937) nor multiple bacteremic/fungemic episodes (II: 13%, ID: 16%, DD: 12%; p=0.641) were different between genotype groups. The ACE I/D polymorphism had no effect on sepsis-related mortality (II: 7%, ID: 5%, DD: 4%; p=0.692). Sepsis mortality for infants with late BSI was 14% in infants with the II genotype, 9% with the ID genotype and 10% with the DD genotype (p=0.764).

CONCLUSIONS

The ACE I/D polymorphism does not have a significant effect on the incidence or outcome of sepsis in ventilated VLBW infants.

Bronchopulmonary dysplasia in preterm infants: pathophysiology and management strategies

Bronchopulmonary dysplasia (BPD) has classically been described as including inflammation, architectural disruption, fibrosis, and disordered/delayed development of the infant lung. As infants born at progressively earlier gestations have begun to survive the neonatal period, a 'new' BPD, consisting primarily of disordered/delayed development, has emerged. BPD causes not only significant complications in the newborn period, but is associated with continuing mortality, cardiopulmonary dysfunction, re-hospitalization, growth failure, and poor neurodevelopmental outcome after hospital discharge. Four major risk factors for BPD include premature birth, respiratory failure, oxygen supplementation, and mechanical ventilation, although it is unclear whether any of these factors is absolutely necessary for development of the condition. Genetic susceptibility, infection, and patent ductus arteriosus have also been implicated in the pathogenesis of the disease. The strategies with the strongest evidence for effectiveness in preventing or lessening the severity of BPD include prevention of prematurity and closure of a clinically significant patent ductus arteriosus. Some evidence of effectiveness also exists for single-course therapy with antenatal glucocorticoids in women at risk for delivering premature infants, surfactant replacement therapy in intubated infants with respiratory distress syndrome, retinol (vitamin A) therapy, and modes of respiratory support designed to minimize 'volutrauma' and oxygen toxicity. The most effective treatments for ameliorating symptoms or preventing exacerbation in established BPD include oxygen therapy, inhaled glucocorticoid therapy, and vaccination against respiratory pathogens.Many other strategies for the prevention or treatment of BPD have been proposed, but have weaker or conflicting evidence of effectiveness. In addition, many therapies have significant side effects, including the possibility of worsening the disease despite symptom improvement. For instance, supraphysiologic systemic doses of glucocorticoids lessen the incidence of BPD in infants at risk for the disease, and promote weaning of oxygen and mechanical ventilation in infants with established BPD. However, the side effects of systemic glucocorticoid therapy, most notably the recently recognized adverse effects on neurodevelopment, preclude their routine use for the prevention or treatment of BPD. Future research in BPD will most probably focus on continued incremental improvements in outcome, which are likely to be achieved through the combined effects of many therapeutic modalities.

The Angiotensin Converting Enzyme Insertion/Deletion polymorphism is not associated with an increased risk of death or bronchopulmonary dysplasia in ventilated very low birth weight infants

BACKGROUND

The ACE gene contains a polymorphism consisting of either the presence (insertion, I) or absence (deletion, D) of a 287 bp alu repeat in intron 16. The D allele is associated with increased ACE activity in both tissue and plasma. The DD genotype is associated with risk of developing ARDS and mortality. The frequency of the D allele is higher in patients with pulmonary fibrosis, sarcoidosis and berylliosis. The role of this polymorphism has not been studied in the development of BPD in the premature newborn.

METHODS

ACE I/D genotype was determined in 245 (194 African-American, 47 Caucasian and 4 Hispanic) mechanically ventilated infants weighing less than 1250 grams at birth and compared to outcome (death and/or development of BPD).

RESULTS

The incidence of the D allele in the study population was 0.58. Eighty-eight (35.9%) infants were homozygous DD, 107 (43.7%) were heterozygous ID and 50 (20.4%) were homozygous II. There were no significant differences between genotype groups with respect to ethnic origin, birth weight, gestation, or gender. There was no effect of the ACE I/D polymorphism on mortality or development of BPD (O2 on 28 days or 36 weeks PCA). Secondary outcomes (intraventricular hemorrhage and periventricular leukomalacia) similarly were not influenced by the ACE ID polymorphism.

CONCLUSIONS

The ACE I/D polymorphism does not significantly influence the development of BPD in ventilated infants less than 1250 grams.

Elevated platelet-derived growth factor-BB concentrations in premature neonates who develop chronic lung disease

BACKGROUND

Chronic lung disease (CLD) in the preterm newborn is associated with inflammation and fibrosis. Platelet-derived growth factor-BB (PDGF-BB), a potent chemotactic growth factor, may mediate the fibrotic component of CLD. The objectives of this study were to determine if tracheal aspirate (TA) concentrations of PDGF-BB increase the first 2 weeks of life in premature neonates undergoing mechanical ventilation for respiratory distress syndrome (RDS), its relationship to the development of CLD, pulmonary hemorrhage (PH) and its relationship to airway colonization with Ureaplasma urealyticum (Uu).

METHODS

Infants with a birth weight less than 1500 grams who required mechanical ventilation for RDS were enrolled into this study with parental consent. Tracheal aspirates were collected daily during clinically indicated suctioning. Uu cultures were performed on TA collected in the first week of life. TA supernatants were assayed for PDGF-BB and secretory component of IgA concentrations using ELISA techniques.

RESULTS

Fifty premature neonates were enrolled into the study. Twenty-eight infants were oxygen dependent at 28 days of life and 16 infants were oxygen dependent at 36 weeks postconceptual age. PDGF-BB concentrations peaked between 4 and 6 days of life. Maximum PDGF-BB concentrations were significantly higher in infants who developed CLD or died from respiratory failure. PH was associated with increased risk of CLD and was associated with higher PDGF-BB concentrations. There was no correlation between maximum PDGF-BB concentrations and Uu isolation from the airway.

CONCLUSIONS

PDGF-BB concentrations increase in TAs of infants who undergo mechanical ventilation for RDS during the first 2 weeks of life and maximal concentrations are greater in those infants who subsequently develop CLD. Elevation in lung PDGF-BB may play a role in the development of CLD.

Monocyte chemotactic protein-1 in cervical and amniotic fluid: relationship to microbial invasion of the amniotic cavity, intra-amniotic inflammation, and preterm delivery

OBJECTIVE

The purpose of this study was to evaluate the role of monocyte chemotactic protein-1 in cervical and amniotic fluid in women in preterm labor and with preterm premature rupture of membranes.

STUDY DESIGN

Women with singleton pregnancies (<or=34 weeks) in preterm labor (n=75 women), with preterm premature rupture of membranes (n=47 women), and at term (n=45 women) who were undergoing elective cesarean delivery were included. Cervical and amniotic fluid were sampled.

RESULTS

Monocyte chemotactic protein-1 in cervical and amniotic fluid was higher in women in preterm labor than in women at term. Cervical monocyte chemotactic protein-1 in women in preterm labor was associated with microbial invasion of the amniotic cavity, intra-amniotic inflammation, delivery within 7 days, and at <or=34 weeks. Amniotic monocyte chemotactic protein-1 correlated to microbial invasion of the amniotic cavity in women with preterm premature rupture of membranes, intra-amniotic inflammation in preterm labor, preterm premature rupture of membranes, delivery within 7 days, and delivery at <or=34 weeks in women in preterm labor.

CONCLUSION

Monocyte chemotactic protein-1 in cervical and amniotic fluid levels are elevated in preterm labor and preterm premature rupture of membranes and correlate to intra-amniotic infection/inflammation.