Search

Bronchopulmonary dysplasia (BPD) is a chronic lung disease of prematurity. Exposure to noxious stimuli such as hyperoxia, volutrauma, and infection in infancy can have long-reaching impacts on lung health and predispose towards the development of conditions such as chronic obstructive pulmonary disease (COPD) in adulthood. BPD and COPD are both marked by lung tissue degradation, neutrophil influx, and decreased lung function. Both diseases also express a change in microbial signature dominated byProteobacteriaabundance andLactobacillusscarcity. However, the relationship between pulmonary microbial dysbiosis and the mechanisms of downstream disease development has yet to be elucidated. We hypothesized that a double-hit hyperoxia and LPS murine model of BPD would show heightened Ac-PGP pathway and neutrophil activity. Through gain- and loss-of-function studies in the same model we showed that Ac-PGP plays a critical role in driving BPD development. We tested a novel inhaled live biotherapeutic using activeLactobacillusstrains to counteract lung dysbiosis inin vitroandin vivomodels of BPD and COPD. TheLactobacillusLBP is effective in improving lung structure and function, reducing neutrophil influx, and reducing a broad swath of pro-inflammatory markers in these models of chronic pulmonary disease. Live inhaled microbiome-based therapeutics show promise in addressing common pathways of disease progression that in the future can be targeted in a variety of chronic lung diseases.

Rationale: Dysbiosis of the gut microbiome may augment lung disease via the gut-lung axis. Proteobacteria may increase MMP-9 release and contribute to tissue proteolysis followed by neutrophil recruitment, lung tissue injury, and perpetuation of chronic lung disease. Trial Design: We sought to determine if a probiotic and herbal blend was safe and well-tolerated in healthy volunteers and asthmatic patients. Methods: We conducted a 1-month randomized, open-label clinical trial in Cork, Ireland with healthy and asthmatic patients who took the blend twice a day. The primary endpoint was safety with secondary endpoints including quality of life, lung function, gut microbiome ecology, and inflammatory biomarkers. Results: All subjects tolerated the blend without adverse events. Asthmatic subjects who took the blend showed significant improvements in lung function and serum short chain fatty acid levels from baseline to Week 4. The gut microbiome of asthmatic subjects differed significantly from controls, with the most prominent difference in the relative abundance of the proteobacteria Escherichia coli. Administration of the probiotic maintained overall microbial community architecture with the only significant difference being an increase in absolute abundance of the probiotic strains measured by strain-specific PCR. Conclusions: This study supports the safety and efficacy potential of oral probiotic administration of the probiotic and herbal to act on the gut-lung axis.

Background Early progression of feeding could influence the development of the gut microbiome. Methods We collected fecal samples from extremely preterm infants randomized to receive either early (feeding day 2) or delayed (feeding day 5) feeding progression. After study completion, we compared samples obtained at three different time points (week 1, week 2, and week 3) to determine longitudinal differences in specific taxa between the study groups using unadjusted and adjusted negative binomial and zero-inflated mixed models. Analyses were adjusted for a mode of delivery, breastmilk intake, and exposure to antibiotics. Results We analyzed 137 fecal samples from 51 infants. In unadjusted and adjusted analyses, we did not observe an early transition to higher microbial diversity within samples (i.e., alpha diversity) or significant differences in microbial diversity between samples (i.e., beta diversity) in the early feeding group. Our longitudinal, single-taxon analysis found consistent differences in the genera Lactococcus, Veillonella, and Bilophila between groups. Conclusions Differences in single-taxon analyses independent of the mode of delivery, exposure to antibiotics, and breastmilk feeding suggest potential benefits of early progression of enteral feeding volumes. However, this dietary intervention does not appear to increase the diversity of the gut microbiome in the first 28 days after birth. Trial Registration ClinicalTrials.gov identifier: NCT02915549. Impact Early progression of enteral feeding volumes with human milk reduces the duration of parenteral nutrition and the need for central venous access among extremely preterm infants. Early progression of enteral feeding leads to single-taxon differences in longitudinal analyses of the gut microbiome, but it does not appear to increase the diversity of the gut microbiome in the first 28 days after birth. Randomization in enteral feeding trials creates appealing opportunities to evaluate the effects of human milk diets on the gut microbiome.

Infants with gestational age between 22 0/7 and 23 6/7 weeks (referred to as nano-preterm infants) are at very high risk of adverse outcomes. Noninvasive respiratory support at birth improves outcomes in infants born at 24 0/7 to 27 6/7 weeks' gestational age. Evidence is limited on whether similar benefits of non-invasive respiratory support at birth extend to nano-preterm infants.To evaluate the hypothesis that intubation at 10 minutes or earlier after birth is associated with a higher incidence of bronchopulmonary dysplasia (BPD) or death by 36 weeks' postmenstrual age (PMA) in nano-preterm infants.This observational cohort study included all nano-preterm infants at a level IV neonatal intensive care unit who were delivered from January 1, 2014, to June 30, 2021. Infants receiving palliative or comfort care at birth were excluded.Infants were grouped based on first intubation attempt timing after birth (10 minutes after birth and ≤10 minutes as noninvasive and invasive respiratory support at birth groups, respectively).The primary outcome was the composite outcome of BPD (physiological definition) or death by 36 weeks' PMA.All 230 consecutively born, eligible nano-preterm infants were included, of whom 88 (median [IQR] gestational age, 23.6 [23.4-23.7] weeks; 45 [51.1%] female; 54 [62.1%] Black) were in the noninvasive respiratory support at birth group and 142 (median [IQR] gestational age, 23.0 [22.4-23.3] weeks; 71 [50.0%] female; 94 [66.2%] Black) were in the invasive respiratory support at birth group. The incidence of BPD or death by 36 weeks' PMA did not differ between the noninvasive and invasive respiratory support groups (83 of 88 [94.3%] in the noninvasive group vs 129 of 142 [90.9%] in the invasive group; adjusted odds ratio, 2.09; 95% CI, 0.60-7.25; P = .24). Severe intraventricular hemorrhage or death by 36 weeks' PMA was lower in the invasive respiratory support at birth group (adjusted odds ratio, 2.20; 95% CI, 1.07-4.51; P = .03).This cohort study's findings suggest that noninvasive respiratory support in the first 10 minutes after birth is feasible but is not associated with a decrease in the risk of BPD or death compared with intubation and early surfactant delivery in nano-preterm infants.

BackgroundMicroRNA (miR) are small conserved RNA that regulate gene expression post-transcription. Previous genome-wide analysis studies in preterm infants indicate that pathways of miR 219-5p are important in infants with Bronchopulmonary Dysplasia (BPD).MethodsHere we report a prospective cohort study of extremely preterm neonates wherein infants diagnosed with severe BPD expressed increased airway miR-219-5p and decreased platelet derived growth factor receptor alpha (PDGFR-α), a target of mir-219-5p and a key regulator of alveolarization, compared to post-conception age-matched term infants.ResultsmiR-219-5p was highly expressed in the pulmonary epithelial lining in lungs of infants with BPD by in situhybridizationof human infant lungs. In both in vitro and in vivo (mouse) models of BPD, miR-219-5p was increased on exposure to hyperoxia compared with the normoxia control, with a complementary decrease of PDGFR-α. To further confirm the target relationship between miR‐219 and PDGFR-α, pulmonary epithelial cells (MLE12) and lung primary fibroblasts were treated with a mimic of miR-219-5p and a locked nucleic acid (LNA) based inhibitor of miR-219-5p. In comparison with the control group, the level of miR‐219 increased significantly after miR‐219 mimic treatment, while the level of PDGFR-α declined markedly. LNA exposure increased PDGFR-α. Moreover, in BPD mouse model, over-expression of miR-219-5p inhibited alveolar development, indicated by larger alveolar spaces accompanied by reduced septation.ConclusionsTaken together, our results demonstrate that increased miR-219-5p contributes to the pathogenesis of BPD by targeting and reducing PDGFR-α. The use of specific miRNA antagonists may be a therapeutic strategy for preventing the development of BPD.

Rationale Bronchopulmonary dysplasia (BPD) is the most common complication of prematurity and significantly contributes to mortality and morbidity with few predictive biomarkers. Given that nitrites have been implicated in pathways associated with lung disease, we hypothesized that nitrite levels would be altered in the airways of premature infants diagnosed with BPD. Methods This was a prospective cohort study of extremely low birth infants ( Results Infants with BPD were found to have significantly elevated nitrite levels in their tracheal aspirates compared to gestation matched FT controls (p p = 0.05). Conclusions In conclusion, nitrite levels are significantly increased in airways of infants with BPD. Data from a larger cohort are needed to further support the utility of nitrite for BPD prediction. Trial registration Not applicable.

Airway microbial dysbiosis is associated with subsequent bronchopulmonary dysplasia (BPD) development in very preterm infants. However, the relationship of airway microbiome in normal pulmonary development has not been defined. To better understand the role of the airway microbiome, we compared normal and abnormal alveolar and pulmonary vascular development in mice with or without a microbiome. We hypothesized that the lungs of germ-free (GF) mice would have an exaggerated phenotypic response to hyperoxia compared with non–germ-free (NGF) mice. With the use of a novel gnotobiotic hyperoxia chamber, GF and NGF mice were exposed to either normoxia or hyperoxia. Alveolar morphometry, pulmonary mechanics, echocardiograms, inflammatory markers, and measures of pulmonary hypertension were studied. GF and NGF mice in normoxia showed no difference, whereas GF mice in hyperoxia showed protected lung structure and mechanics and decreased markers of inflammation compared with NGF mice. We speculate that an increase in abundance of pathogenic bacteria in NGF mice may play a role in BPD pathogenesis by regulating the proinflammatory signaling and neutrophilic inflammation in lungs. Manipulation of the airway microbiome may be a potential therapeutic intervention in BPD and other lung diseases.

Emerging evidence indicates that early life events can increase the risk for developing chronic obstructive pulmonary disease (COPD). Using an inducible transgenic mouse model for NF-κB activation in the airway epithelium, we found that a brief period of inflammation during the saccular stage (P3–P5) but not alveolar stage (P10–P12) of lung development disrupted elastic fiber assembly, resulting in permanent reduction in lung function and development of a COPD-like lung phenotype that progressed through 24 months of age. Neutrophil depletion prevented disruption of elastic fiber assembly and restored normal lung development. Mechanistic studies uncovered a role for neutrophil elastase (NE) in downregulating expression of critical elastic fiber assembly components, particularly fibulin-5 and elastin. Further, purified human NE and NE-containing exosomes from tracheal aspirates of premature infants with lung inflammation downregulated elastin and fibulin-5 expression by saccular-stage mouse lung fibroblasts. Together, our studies define a critical developmental window for assembling the elastin scaffold in the distal lung, which is required to support lung structure and function throughout the lifespan. Although neutrophils play a well-recognized role in COPD development in adults, neutrophilic inflammation may also contribute to early-life predisposition to COPD.

Dry eye affects millions of individuals. In experimental models, dry eye disease is associated with T helper cell 17-mediated inflammation of the ocular surface that may cause persistent damage to the corneal epithelium. However, the initiating and perpetuating factors associated with chronic inflammation of the ocular surface remain unclear. The ocular microbiota alters ocular surface inflammation and may influence dry eye disease development and progression. Here, we collected serial samples of tears on awakening from sleep, closed eye tears, during a randomized clinical trial of a non-pharmaceutical dry eye therapy and used 16S rRNA metabarcoding to characterize the microbiome. We show the closed dry eye microbiome is distinct from the healthy closed eye microbiome, and that the microbiome remains distinct despite daily saline eye wash upon awakening. The ocular microbiome was described only recently, and this report implicates a distinct microbiome in ocular disease development. Our findings suggest an interplay between microbial commensals and inflammation on the ocular surface. This information may inform future studies of the pathophysiological mechanisms of dry eye disease.

Altered inflammation and tissue remodeling are cardinal features of cardiovascular disease and cardiac transplant rejection. Neutrophils have increasingly been understood to play a critical role in acute rejection and early allograft failure; however, discrete mechanisms that drive this damage remain poorly understood. Herein, we demonstrate that early acute cardiac rejection increases allograft prolyl endopeptidase (PE) in association with de novo production of the neutrophil proinflammatory matrikine proline-glycine-proline (PGP). In a heterotopic murine heart transplant model, PGP production and PE activity were associated with early neutrophil allograft invasion and allograft failure. Pharmacologic inhibition of PE with Z-Pro-prolinal reduced PGP, attenuated early neutrophil graft invasion, and reduced proinflammatory cytokine expression. Importantly, these changes helped preserve allograft rejection-free survival and function. Notably, within 2 independent patient cohorts, both PGP and PE activity were increased among patients with biopsy-proven rejection. The observed induction of PE and matrikine generation provide a link between neutrophilic inflammation and cardiovascular injury, represent a potential target to reduce allogenic immune responses, and uncover a mechanism of cardiovascular disease that has been previously unrecognized to our knowledge.

Dry eye affects millions of individuals. In experimental models, dry eye disease is associated with T helper cell 17-mediated inflammation of the ocular surface that may cause persistent damage to the corneal epithelium. However, the initiating and perpetuating factors associated with chronic inflammation of the ocular surface remain unclear. The ocular microbiota alters ocular surface inflammation and may influence dry eye disease development and progression. Here, we collected serial samples of closed eye tears during a randomized clinical trial of a non-pharmaceutical dry eye therapy and used 16S rRNA metabarcoding to characterize the microbiome. We show the closed dry eye microbiome is distinct from the healthy closed eye microbiome. The ocular microbiome was described only recently, and this report implicates a distinct microbiome in ocular disease development. Our findings suggest an interplay between microbial commensals and inflammation on the ocular surface. This information may inform future studies of the pathophysiological mechanisms of dry eye disease.

Bronchopulmonary dysplasia (BPD) is a developmental disorder of the premature lungs stemming from a multifactorial etiology and has a variable clinical phenotype. Innovative systems-biology based ‘omic’ approaches may help define the cellular and humoral interactions that regulate lung development and injury associated abnormalities and can provide better insights into the etiopathogenesis and potential novel therapeutic options related to BPD. MicroRNAs (miRs) are small non-coding RNAs that have increasingly been implicated in several lung diseases, including BPD. This chapter highlights the various miRs which have been studied in the pathogenesis of BPD. In addition, it discusses their potential role as targeted therapy for BPD.

The advent of culture-independent microbiologic techniques has demonstrated relationships between the composition of the airway microbiota (microbial communities in the respiratory tract) and many pulmonary disorders. Recent scientific discoveries have provided insight into the establishment of the airway microbiome in the neonate and its early postnatal changes that are associated with short-term and long-term pulmonary outcomes. Airway microbial dysbiosis may have a causal association with bronchopulmonary dysplasia and many ongoing studies are currently exploring the underlying molecular mechanisms. The precise mechanisms by which the pulmonary microbiome is modulated after birth continue to remain uncertain. Future studies are warranted to test the therapeutic benefits of pulmonary microbiome manipulation by probiotics, prebiotics, and specific antimicrobial therapy.

Epigenetics involves modifications of DNA bases and histone proteins, as well as noncoding-RNA-based mechanisms regulating host gene expression. Metagenomics refers to the genetic material of the ecosystem within the organism, commonly microbial DNA/RNA within the host. The pathogenesis of bronchopulmonary dysplasia (BPD) is multifactorial and the clinical phenotype of BPD is extremely variable. Over the years, newer technologies have identified alterations of epigenetic regulation involved in lung development and injury. The literature on epigenetic modifications in BPD is summarized. We also briefly review the emerging field of the influence of airway microbiome in the pathogenesis of BPD. The rapidly changing technology in the epigenetic field and the increasing amenability to manipulation suggest that epigenetics-based prognostic and therapeutic procedures may be the future of neonatal pulmonary medicine.

Acute respiratory distress syndrome (ARDS) is characterized by unrelenting polymorphonuclear neutrophil (PMN) inflammation and vascular permeability. The matrikine proline-glycine-proline (PGP) and acetylated PGP (Ac-PGP) have been shown to induce PMN inflammation and endothelial permeability in vitro and in vivo. In this study, we investigated the presence and role of airway PGP peptides in acute lung injury (ALI)/ARDS. Pseudomonas aeruginosa-derived lipopolysaccharide (LPS) was instilled intratracheally in mice to induce ALI, and increased Ac-PGP with neutrophil inflammation was noted. The PGP inhibitory peptide, arginine-threonine-arginine (RTR), was administered (it) 30 min before or 6 h after LPS injection. Lung injury was evaluated by detecting neutrophil infiltration and permeability changes in the lung. Pre- and posttreatment with RTR significantly inhibited LPS-induced ALI by attenuating lung neutrophil infiltration, pulmonary permeability, and parenchymal inflammation. To evaluate the role of PGP levels in ARDS, minibronchoalveolar lavage was collected from nine ARDS, four cardiogenic edema, and five nonlung disease ventilated patients. PGP levels were measured and correlated with Acute Physiology and Chronic Health Evaluation (APACHE) score, [Formula: see text] to [Formula: see text] (P/F), and ventilator days. PGP levels in subjects with ARDS were significantly higher than cardiogenic edema and nonlung disease ventilated patients. Preliminary examination in both ARDS and non-ARDS populations demonstrated PGP levels significantly correlated with P/F ratio, APACHE score, and duration on ventilator. These results demonstrate an increased burden of PGP peptides in ARDS and suggest the need for future studies in ARDS cohorts to examine correlation with key clinical parameters.

Cyclooxygenase-2 (COX-2/PTGS2) mediates hyperoxia-induced impairment of lung development in newborn animals and is increased in the lungs of human infants with bronchopulmonary dysplasia (BPD). COX-2 catalyzes the production of cytoprotective prostaglandins, such as prostacyclin (PGI2), as well as proinflammatory mediators, such as thromboxane A2. Our objective was to determine whether iloprost, a synthetic analog of PGI2, would attenuate hyperoxia effects in the newborn mouse lung. To test this hypothesis, newborn C57BL/6 mice along with their dams were exposed to normoxia (21% O2) or hyperoxia (85% O2) from 4 to 14 days of age in combination with daily intraperitoneal injections of either iloprost 200 µg·kg−1·day−1, nimesulide (selective COX-2 antagonist) 100 mg·kg−1·day−1, or vehicle. Alveolar development was estimated by radial alveolar counts and mean linear intercepts. Lung function was determined on a flexiVent, and multiple cytokines and myeloperoxidase (MPO) were quantitated in lung homogenates. Lung vascular and microvascular morphometry was performed, and right ventricle/left ventricle ratios were determined. We determined that iloprost (but not nimesulide) administration attenuated hyperoxia-induced inhibition of alveolar development and microvascular density in newborn mice. Iloprost and nimesulide both attenuated hyperoxia-induced, increased lung resistance but did not improve lung compliance that was reduced by hyperoxia. Iloprost and nimesulide reduced hyperoxia-induced increases in MPO and some cytokines (IL-1β and TNF-α) but not others (IL-6 and KC/Gro). There were no changes in pulmonary arterial wall thickness or right ventricle/left ventricle ratios. We conclude that iloprost improves lung development and reduces lung inflammation in a newborn mouse model of BPD.

Rationale: MicroRNAs (miRNAs) destabilize mRNA transcripts and inhibit protein translation. miR-145 is of particular interest in cystic fibrosis (CF) as it has a direct binding site in the 3′-untranslated region of CFTR (cystic fibrosis transmembrane conductance regulator) and is upregulated by the CF genetic modifier TGF (transforming growth factor)-β. Objectives: To demonstrate that miR-145 mediates TGF-β inhibition of CFTR synthesis and function in airway epithelia. Methods: Primary human CF (F508del homozygous) and non-CF airway epithelial cells were grown to terminal differentiation at the air–liquid interface on permeable supports. TGF-β (5 ng/ml), a miR-145 mimic (20 nM), and a miR-145 antagonist (20 nM) were used to manipulate CFTR function. In CF cells, lumacaftor (3 μM) and ivacaftor (10 μM) corrected mutant F508del CFTR. Quantification of CFTR mRNA, protein, and function was done by standard techniques. Measurements and Main Results: miR-145 is increased fourfold in CF BAL fluid compared with non-CF (P

Objective To evaluate the impact of the Neonatal Resuscitation Program (NRP)-recommended low oxygen strategy (LOX) on neonatal morbidities, mortality, and neurodevelopmental outcomes in neonates born preterm. Study design In March 2011, Parkland Hospital changed from a high oxygen strategy (HOX) of resuscitation with initial 100% oxygen and targeting 85%-94% oxygen saturation for delivery room resuscitation to a LOX with initial 21% oxygen and titrating oxygen to meet NRP-recommended transitional target saturations. Neonates ≤28 weeks' gestational age born between August 2009 and April 2012 were identified. In this retrospective, observational study, neonates exposed to LOX vs HOX were compared for short-term morbidity, mortality, and long-term neurodevelopmental outcomes. Regression analysis was performed to control for confounding variables. Results Of 199 neonates, 110 were resuscitated with HOX and 89 with LOX. Compared with HOX, neonates exposed to LOX had lower oxygen exposure in the delivery room (5.2 ± 1.5 vs 7.8 ± 2.8 [∑FiO 2 × time min ], P P = .01), and had lower odds of developing bronchopulmonary dysplasia (aOR 0.4 [0.2, 0.9]). There was no difference in mortality (17 [20%] vs 20 [18%]), but neonates exposed to LOX had greater motor composite scores on Bayley Scales of Infant and Toddler Development–Third edition assessment (91 [85, 97] vs 88 [76, 94], P Conclusion The NRP-recommended LOX strategy was associated with improved respiratory morbidities and neurodevelopmental outcomes with no increase in mortality. Prospective trials to confirm the optimal oxygen strategy for the resuscitation of neonates born preterm are needed.

During the newborn period, intestinal commensal bacteria influence pulmonary mucosal immunology via the gut-lung axis. Epidemiological studies have linked perinatal antibiotic exposure in human newborns to an increased risk for bronchopulmonary dysplasia, but whether this effect is mediated by the gut-lung axis is unknown. To explore antibiotic disruption of the newborn gut-lung axis, we studied how perinatal maternal antibiotic exposure influenced lung injury in a hyperoxia-based mouse model of bronchopulmonary dysplasia. We report that disruption of intestinal commensal colonization during the perinatal period promotes a more severe bronchopulmonary dysplasia phenotype characterized by increased mortality and pulmonary fibrosis. Mechanistically, metagenomic shifts were associated with decreased IL-22 expression in bronchoalveolar lavage and were independent of hyperoxia-induced inflammasome activation. Collectively, these results demonstrate a previously unrecognized influence of the gut-lung axis during the development of neonatal lung injury, which could be leveraged to ameliorate the most severe and persistent pulmonary complication of preterm birth.

Bronchopulmonary dysplasia (BPD) is the chronic lung disease of prematurity with an operational definition, various different clinical phenotypes, and a complex, multifactorial etiology. Newer unbiased systems biology approaches have identified various “omic” factors associated with the pathogenesis and prediction of BPD. Recent microbi “omic” studies have discovered that airways of newborns harbor a low biomass but distinct microbiome signature as early as at the time of birth. This early airway microbiome may serve to prime the host immune system and may play a role in modulating the infant's future susceptibility to severe BPD development. Temporal changes are observed in airway microbiome of preterm infants from birth to the diagnosis of BPD, with an overall decrease in bacterial diversity, and development of a relative dysbiosis marked by increased Gammaproteobacteria and decreased Lactobacilli abundance. This review will summarize previous investigations of the airway microbiome in preterm infants, appraise the utility of using the airway microbiome to predict BPD development, discuss possible molecular mechanisms involved, and speculate on future microbiome-mediated therapeutics for BPD.

A comprehensive understanding of the dynamic regulatory networks that govern postnatal alveolar lung development is still lacking. To construct such a model, we profiled mRNA, microRNA, DNA methylation, and proteomics of developing murine alveoli isolated by laser capture microdissection at 14 predetermined time points. We developed a detailed comprehensive and interactive model that provides information about the major expression trajectories, the regulators of specific key events, and the impact of epigenetic changes. Intersecting the model with single-cell RNA-Seq data led to the identification of active pathways in multiple or individual cell types. We then constructed a similar model for human lung development by profiling time-series human omics data sets. Several key pathways and regulators are shared between the reconstructed models. We experimentally validated the activity of a number of predicted regulators, leading to new insights about the regulation of innate immunity during lung development.

The pathogenesis of bronchopulmonary dysplasia (BPD) is multifactorial and the clinical phenotype of BPD is extremely variable. Hence, many traditional biomarkers have low predictive accuracy for BPD, and none are used in routine clinical care. In recent years, newer technologies have facilitated the in-depth and unbiased analysis of “large data” for early diagnosis or delineating the mechanisms of multiple diseases. Novel systems biology–based “-omic” approaches, including but not limited to genomics, proteomics, metabolomics, and microbiomics, may help define the multiple cellular and humoral interactions that regulate both normal and abnormal lung development and response to injury in BPD. The econ“omics” of these technologies will decide the pace at which personalized medicine is made accessible to preterm neonates at risk of developing BPD or other complications of prematurity.

Myeloid cells are key factors in the progression of bronchopulmonary dysplasia (BPD) pathogenesis. Endothelial monocyte-activating polypeptide II (EMAP II) mediates myeloid cell trafficking. The origin and physiological mechanism by which EMAP II affects pathogenesis in BPD is unknown. The objective was to determine the functional consequences of elevated EMAP II levels in the pathogenesis of murine BPD and to investigate EMAP II neutralization as a therapeutic strategy. Three neonatal mouse models were used: (1) BPD (hyperoxia), (2) EMAP II delivery, and (3) BPD with neutralizing EMAP II antibody treatments. Chemokinic function of EMAP II and its neutralization were assessed by migration in vitro and in vivo. We determined the location of EMAP II by immunohistochemistry, pulmonary proinflammatory and chemotactic gene expression by quantitative polymerase chain reaction and immunoblotting, lung outcome by pulmonary function testing and histological analysis, and right ventricular hypertrophy by Fulton’s Index. In BPD, EMAP II initially is a bronchial club-cell–specific protein–derived factor that later is expressed in galectin-3+ macrophages as BPD progresses. Continuous elevated expression corroborates with baboon and human BPD. Prolonged elevation of EMAP II levels recruits galectin-3+ macrophages, which is followed by an inflammatory state that resembles a severe BPD phenotype characterized by decreased pulmonary compliance, arrested alveolar development, and signs of pulmonary hypertension. In vivo pharmacological EMAP II inhibition suppressed proinflammatory genes Tnfa, Il6, and Il1b and chemotactic genes Ccl2 and Ccl9 and reversed the severe BPD phenotype. EMAP II is sufficient to induce macrophage recruitment, worsens BPD progression, and represents a targetable mechanism of BPD development.

MicroRNAs (miRs) are small conserved RNA that regulate gene expression. Bioinformatic analysis of miRNA profiles during mouse lung development indicated a role for multiple miRNA, including miRNA-489. miR-489 increased on completion of alveolar septation [postnatal day 42 (P42)], associated with decreases in its conserved target genes insulin-like growth factor-1 ( Igf1) and tenascin C ( Tnc). We hypothesized that dysregulation of miR-489 and its target genes Igf1 and Tnc contribute to hyperoxia-induced abnormal lung development. C57BL/6 mice were exposed to normoxia (21%) or hyperoxia (85% O2) from P4 to P14, in combination with intranasal locked nucleic acid against miR-489 to inhibit miR-489, cytomegalovirus promoter (pCMV)-miR-489 to overexpress miR-489, or empty vector. Hyperoxia reduced miR-489 and increased Igf1 and Tnc. Locked nucleic acid against miR-489 improved lung development during hyperoxia and did not alter it during normoxia, whereas miR-489 overexpression inhibited lung development during normoxia. The 3′ untranslated region in vitro reporter studies confirmed Igf1 and Tnc as targets of miR-489. While miR-489 was of epithelial origin and present in exosomes, its targets Igf1 and Tnc were produced by fibroblasts. Infants with bronchopulmonary dysplasia (BPD) had reduced lung miR-489 and increased Igf1 and Tnc compared with normal preterm or term infants. These results suggest increased miR-489 is an inhibitor of alveolar septation. During hyperoxia or BPD, reduced miR-489 and increased Igf1 and Tnc may be inadequate attempts at compensation. Further inhibition of miR-489 may permit alveolar septation to proceed. The use of specific miRNA antagonists or agonists may be a therapeutic strategy for inhibited alveolarization, such as in BPD.

Extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae represent a major worldwide threat. We present three cases of early onset ESBL Escherichia coli sepsis in infants born to families from South and Southeast Asia to inform the practitioner community about this emerging threat. Infants with suspected sepsis, whose mother is from Asia or Southeast Asia, should be suspected of having an infection with an ESBL-producing organism, and practitioners should strongly consider adding a carbapenem to their usual initial antibiotic regimen.

The pathogenesis of bronchopulmonary dysplasia (BPD) is not well understood. We previously identified differences in the airway microbiome at birth between preterm infants who were BPD predisposed versus those who were BPD resistant. In this study, we attempted to identify mechanisms by which the airway microbiome could modify the risk for BPD. We used a software-based method to predict the metagenome of the tracheal aspirate (TA) microbiome from 16S rRNA sequencing data in preterm infants and to identify functional ortholog genes that were differentially abundant in BPD-predisposed and BPD-resistant infants. We also identified metabolites that were differentially enriched in these samples by use of untargeted mass spectrometry and mummichog to identify the metabolic pathways involved. Microbial metagenome analysis identified specific pathways that were less abundant in the functional metagenome of the microbiota of BPD-predisposed infants compared with BPD-resistant infants. The airway metabolome of BPD-predisposed infants was enriched for metabolites involved in fatty acid activation and androgen and estrogen biosynthesis compared with BPD-resistant infants. These findings suggest that in extremely preterm infants the early airway microbiome may alter the metabolome, thereby modifying the risk of BPD. The differential enrichment of sex steroid metabolic pathways supports previous studies suggesting a role for sexual dimorphism in BPD risk. This study also suggests a role for metabolomic and metagenomic profiles to serve as early biomarkers of BPD risk.

Preterm infants often require prolonged oxygen supplementation and are at high risk of neurodevelopmental impairment. We recently reported that adult mice exposed to neonatal hyperoxia (postnatal day [P] 2 to 14) had spatial navigation memory deficits associated with hippocampal shrinkage. The mechanisms by which early oxidative stress impair neurodevelopment are not known. Our objective was to identify early hyperoxia-induced alterations in hippocampal receptors and signaling pathways necessary for memory formation. We evaluated C57BL/6 mouse pups at P14, exposed to either 85% oxygen or air from P2 to 14. We performed targeted analysis of hippocampal ligand-gated ion channels and proteins necessary for memory formation, and global bioinformatic analysis of differentially expressed hippocampal genes and proteins. Hyperoxia decreased hippocampal mGLU7, TrkB, AKT, ERK2, mTORC1, RPS6, and EIF4E and increased α3, α5, and ɤ2 subunits of GABAA receptor and PTEN proteins, although changes in gene expression were not always concordant. Bioinformatic analysis indicated dysfunction in mitochondria and global protein synthesis and translational processes. In conclusion, supraphysiological oxygen exposure reduced proteins necessary for hippocampus-dependent memory formation and may adversely impact hippocampal mitochondrial function and global protein synthesis. These early hippocampal changes may account for memory deficits seen in preterm survivors following prolonged oxygen supplementation.

Premature infants are at high risk for developing bronchopulmonary dysplasia (BPD), characterized by chronic inflammation and inhibition of lung development, which we have recently identified as being modulated by microRNAs (miRNAs) and alterations in the airway microbiome. Exosomes and exosomal miRNAs may regulate cell differentiation and tissue and organ development. We discovered that tracheal aspirates from infants with severe BPD had increased numbers of, but smaller, exosomes compared with term controls. Similarly, bronchoalveolar lavage fluid from hyperoxia-exposed mice (an animal model of BPD) and supernatants from hyperoxia-exposed human bronchial epithelial cells (in vitro model of BPD) had increased exosomes compared with air controls. Next, in a prospective cohort study of tracheal aspirates obtained at birth from extremely preterm infants, utilizing independent discovery and validation cohorts, we identified unbiased exosomal miRNA signatures predictive of severe BPD. The strongest signal of reduced miR-876-3p in BPD-susceptible compared with BPD-resistant infants was confirmed in the animal model and in vitro models of BPD. In addition, based on our recent discovery of increased Proteobacteria in the airway microbiome being associated with BPD, we developed potentially novel in vivo and in vitro models for BPD combining Proteobacterial LPS and hyperoxia exposure. Addition of LPS led to a larger reduction in exosomal miR 876-3p in both hyperoxia and normoxia compared with hyperoxia alone, thus indicating a potential mechanism by which alterations in microbiota can suppress miR 876-3p. Gain of function of miR 876-3p improved the alveolar architecture in the in vivo BPD model, demonstrating a causal link between miR 876-3p and BPD. In summary, we provide evidence for the strong predictive biomarker potential of miR 876-3p in severe BPD. We also provide insights on the pathogenesis of neonatal lung disease, as modulated by hyperoxia and microbial product–induced changes in exosomal miRNA 876-3p, which could be targeted for future therapeutic development.

BACKGROUND: Due to insufficient evidence, extremely preterm infants (≤28 wk of gestation) rarely receive early progressive feeding (small increments of feeding volumes between 1 and 4 d after birth). We hypothesized that early progressive feeding increases the number of full enteral feeding days in the first month after birth. OBJECTIVE: The aim of this study was to determine the feasibility and efficacy of early progressive feeding in extremely preterm infants. DESIGN: In this single-center randomized trial, extremely preterm infants born between September 2016 and June 2017 were randomly assigned to receive either early progressive feeding without trophic feeding (early feeding group) or delayed progressive feeding after a 4-d course of trophic feeding (delayed feeding group). Treatment allocation occurred before or on feeding day 1. The primary outcome was the number of full enteral feeding days in the first month after birth. Secondary outcomes were death, necrotizing enterocolitis (NEC), culture-proven sepsis, growth percentiles at 36 wk postmenstrual age, use of parenteral nutrition, and need for central venous access. RESULTS: Sixty infants were included (median gestational age: 26 wk; mean ± SD birth weight: 832 ± 253 g). The primary outcome differed between groups (median difference favoring the early feeding group: +2 d; 95% CI: 0, 3 d; P = 0.02). Early progressive feeding reduced the use of parenteral nutrition (4 compared with 8 d; P ≤ 0.01) and the need for central venous access (9 compared with 13 d; P ≤ 0.01). The outcome of culture-proven sepsis (10% compared with 27%; P = 0.18), restricted growth (weight, length, and head circumference

Bronchopulmonary dysplasia (BPD) is a chronic lung disease of prematurity. Over the years, the BPD phenotype has evolved, but despite various advances in neonatal management approaches, the reduction in the BPD burden is minimal. With the advent of surfactant, glucocorticoids, and new ventilation strategies, BPD has evolved from a disease of structural injury into a new BPD, marked by an arrest in alveolar growth in the lungs of extremely premature infants. This deficient alveolar growth has been associated with a diminution of pulmonary vasculature. Several investigators have described the epithelial / vascular co-dependency and the significant role of crosstalk between vessel formation, alveologenesis, and lung dysplasia's; hence identification and study of factors that regulate pulmonary vascular emergence and inflammation has become crucial in devising effective therapeutic approaches for this debilitating condition. The potent antiangiogenic and proinflammatory protein Endothelial Monocyte Activating Polypeptide II (EMAP II) has been described as a mediator of pulmonary vascular and alveolar formation and its expression is inversely related to the periods of vascularization and alveolarization in the developing lung. Hence the study of EMAP II could play a vital role in studying and devising appropriate therapeutics for diseases of aberrant lung development, such as BPD. Herein, we review the vascular contribution to lung development and the implications that vascular mediators such as EMAP II have in distal lung formation during the vulnerable stage of alveolar genesis.

Objectives To summarize evidence regarding microbial dysbiosis of the airway associated with bronchopulmonary dysplasia (BPD) and to explore heterogeneity among studies. Study design We included studies that evaluated the airway microbiome in preterm infants who developed BPD using culture-independent molecular techniques and reported alpha- and beta-diversity metrics and microbial profiles. Results The 6 included studies had substantial clinical and methodological heterogeneity. Most studies reported the presence of an airway microbiome early after birth and an evolution in the first weeks of life with increasing bacterial loads. The early airway microbiome was dominated by Staphylococcus and Ureaplasma spp. Two studies reported differences in alpha- and beta- diversity indices in preterm infants with BPD compared with those who did not develop BPD. Increased microbial community turnover, changes in the relative abundance of Proteobacteria and Firmicutes, and decreased Lactobacilli were reported with BPD progression. Most included infants were born by cesarean delivery, and a majority were exposed to postnatal antibiotics. No data regarding feeding human milk or correlations with the development of gut microbiota (gut-lung axis) were available. Conclusions Microbial dysbiosis may be associated with BPD progression and severity, and further study of microbiome optimization in preterm infants at risk for BPD is warranted.

The pathogenesis of Bronchopulmonary Dysplasia (BPD) is multifactorial and the clinical phenotype of BPD is extremely variable. Predicting BPD is difficult, as it is a disease with a clinical operational definition but many clinical phenotypes and endotypes. Most biomarkers studied over the years have low predictive accuracy, and none are currently used in routine clinical care or shown to be useful for predicting longer-term respiratory outcome. Targeted cellular and humoral biomarkers and novel systems biology 'omic' based approaches including genomic and microbiomic analyses are described in this review.

Alterations of pulmonary microbiome have been recognized in multiple respiratory disorders. It is critically important to ascertain if an airway microbiome exists at birth and if so, whether it is associated with subsequent lung disease. We found an established diverse and similar airway microbiome at birth in both preterm and term infants, which was more diverse and different from that of older preterm infants with established chronic lung disease (bronchopulmonary dysplasia). Consistent temporal dysbiotic changes in the airway microbiome were seen from birth to the development of bronchopulmonary dysplasia in extremely preterm infants. Genus Lactobacillus was decreased at birth in infants with chorioamnionitis and in preterm infants who subsequently went on to develop lung disease. Our results, taken together with previous literature indicating a placental and amniotic fluid microbiome, suggest fetal acquisition of an airway microbiome. We speculate that the early airway microbiome may prime the developing pulmonary immune system and dysbiosis in its development may set the stage for subsequent lung disease.