Vitamin A supplementation in extremely low-birth-weight infants: subgroup analysis in small-for-gestational-age infants

Vitamin A Status in Preterm Infants Is Associated with Inflammation and Dexamethasone Exposure

Vitamin A has a key role in lung development and its deficiency is associated with an increased risk of bronchopulmonary dysplasia. This secondary cohort analysis of the ImNuT trial (Immature, Nutrition Therapy NCT03555019) aimed to (1) explore vitamin A status in preterm infants <29 weeks gestation and (2) assess the influence of inflammation and postnatal dexamethasone exposure on vitamin A concentrations in blood. We report detailed information on vitamin A biochemistry, vitamin A intake, markers of inflammation and dexamethasone exposure. After four weeks of age, infants exposed to dexamethasone (n = 39) showed higher vitamin A concentrations compared to unexposed infants (n = 41); median (IQR) retinol was 1.0 (0.74, 1.5) vs. 0.56 (0.41, 0.74) µmol/L, p < 0.001. Pretreatment retinol concentrations were lower in the dexamethasone group compared to non-exposed infants (p < 0.001); 88% vs. 60% of the infants were considered deficient in vitamin A (retinol < 0.7 µmol/L) at one week of age. Small size for gestational age, mechanical ventilation and elevated levels of interleukin-6 were factors negatively associated with first-week retinol concentrations. In conclusion, preterm infants <29 weeks gestation are at risk of vitamin A deficiency despite intakes that accommodate current recommendations. The presence of inflammation and dexamethasone exposure should be considered when interpreting vitamin A status.

Antioxidants: Role the in prevention and treatment of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is one of the major causes of chronic respiratory diseases among infants. Both pharmacological and nonpharmacological approaches have been proposed for its management. Since oxidative stress is known to play a pivotal role in the pathogenesis of BPD, it is reasonable to consider the potential of antioxidant strategies in the prevention and treatment of this condition. Indeed, antioxidants can prevent or inhibit substrate oxidation. Some studies have evaluated the efficacy of the exogenous administration of vitamins and micronutrients in reducing the propagation of free radicals through their scavenging capacity. Nonetheless, encouraging preclinical results did not translate into effective preventive and/or therapeutic interventions. This narrative review evaluates the current evidence about the antioxidants that are potentially useful for preventing and treating BPD and explores the most relevant issues affecting their implementation in clinical practice, as well as their associated evidence gaps and research limitations.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Serum vitamin A levels as a novel predictor for respiratory distress syndrome in neonates: is it beneficial?

BACKGROUND

Neonatal respiratory distress syndrome (RDS) is a very important dangerous disease in neonates and is accompanied by neonatal complications and death.

OBJECTIVE

Early determination of neonatal serum vitamin A levels as a possible novel predictor for neonatal RDS.

PATIENTS AND METHODS

A case-control study, with the identification number TCTR20210206001 was done on 100 neonates who were admitted to the neonatal intensive care unit (NICU) of Tanta University Hospital (TUH) suffering from RDS (patient group) and 100 healthy neonates (control group). Estimation of serum vitamin A (retinol) was occurred for all neonates of this study within the first four hours after birth before any nutrition or therapies.

RESULTS

Showed no significant difference between serums retinol (RT) levels in grade 1&2 RDS neonates (patient group) and the serum RT levels in the control group while there was significant difference between serums retinol levels in grade 3&4 RDS neonates (patient group) and the serum retinol levels in the control group where the P-value was 0.006, 0.002 respectively.

CONCLUSION

Serum vitamin A levels in neonates were decreased in RDS neonates and could be used as a predictor for the development and severity of RDS.

RECOMMENDATION

Routine estimation of serum vitamin A levels in neonates as a novel predictor for neonatal RDS.

Should Vitamin A Injections to Prevent Bronchopulmonary Dysplasia or Death Be Reserved for High-Risk Infants? Reanalysis of the National Institute of Child Health and Human Development Neonatal Research Network Randomized Trial

OBJECTIVE

To determine whether infants at higher risk of bronchopulmonary dysplasia (BPD) or death benefit more from vitamin A therapy than those at lower risk.

STUDY DESIGN

We conducted a post hoc reanalysis of a landmark phase III randomized controlled trial conducted from January 1996 to July 1997 at 14 university-affiliated neonatal intensive care units in the US. Data analysis was performed from October 2019 to October 2020. Infants born weighing 401-1000 g and receiving respiratory support at 24 hours of age were assigned to intramuscular vitamin A 5000 IU or sham procedure 3 times weekly for 4 weeks. The primary outcome was BPD, defined as use of supplemental oxygen, or death at 36 weeks postmenstrual age. An externally validated model for predicting BPD or death was used to estimate the risk of these outcomes for each infant.

RESULTS

As previously reported, 222 of 405 infants (54.8%) assigned vitamin A therapy and 248 of 402 infants (61.7%) in the control group developed BPD or died (relative risk [RR], 0.89 [95% CI, 0.80-0.99]; risk difference [RD], -6.9% [95% CI, -13.0 to -0.7]). The predicted individual risks of BPD or death ranged from 7.1% to 98.6% (median, 61.5%; mean, 60.9%). The effect of vitamin A therapy on BPD or death depended on infants' risk of the primary outcome (P = .03 for interaction): for example, a RR of 0.73 (RD, -14.5%) for infants with a 25% predicted risk and a RR of 0.96 (RD, -1.0%) for infants with a 75% risk. There was no difference in the decrease in vitamin A deficiency across risk groups.

CONCLUSIONS

Contrary to expectations, the effect of vitamin A therapy on BPD or death was greater for lower risk than higher risk infants.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01203488.

Intrauterine Hypoxia and Epigenetic Programming in Lung Development and Disease

Clinically, intrauterine hypoxia is the foremost cause of perinatal morbidity and developmental plasticity in the fetus and newborn infant. Under hypoxia, deviations occur in the lung cell epigenome. Epigenetic mechanisms (e.g., DNA methylation, histone modification, and miRNA expression) control phenotypic programming and are associated with physiological responses and the risk of developmental disorders, such as bronchopulmonary dysplasia. This developmental disorder is the most frequent chronic pulmonary complication in preterm labor. The pathogenesis of this disease involves many factors, including aberrant oxygen conditions and mechanical ventilation-mediated lung injury, infection/inflammation, and epigenetic/genetic risk factors. This review is focused on various aspects related to intrauterine hypoxia and epigenetic programming in lung development and disease, summarizes our current knowledge of hypoxia-induced epigenetic programming and discusses potential therapeutic interventions for lung disease.

Recent advances in understanding and management of bronchopulmonary dysplasia

In the current era, the survival of extremely low-birth-weight infants has increased considerably because of new advances in technology; however, these infants often develop chronic dysfunction of the lung, which is called bronchopulmonary dysplasia (BPD). BPD remains an important cause of neonatal mortality and morbidity despite newer and gentler modes of ventilation. BPD results from the exposure of immature lungs to various antenatal and postnatal factors that lead to an impairment in lung development and aberrant growth of lung parenchyma and vasculature. However, we still struggle with a uniform definition for BPD that can help predict various short- and long-term pulmonary outcomes. With new research, our understanding of the pathobiology of this disease has evolved, and many new mechanisms of lung injury and repair are now known. By utilizing the novel ‘omic’ approaches in BPD, we have now identified various factors in the disease process that may act as novel therapeutic targets in the future. New investigational agents being explored for the management and prevention of BPD include mesenchymal stem cell therapy and insulin-like growth factor 1. Despite this, many questions remain unanswered and require further research to improve the outcomes of premature infants with BPD.

EARLY VITAMIN A SUPPLEMENTATION IMPROVES THE OUTCOME OF RETINOPATHY OF PREMATURITY IN EXTREMELY PRETERM INFANTS

PURPOSE

This study assessed the efficacy and safety of early vitamin A (VA) supplementation to improve outcomes of retinopathy of prematurity in extremely preterm infants.

METHODS

A total of 262 eligible extremely preterm infants underwent randomization; of these, 132 were assigned to the VA group and 130 to the control group. The infants were administered a solution of VA (1,500 IU/day), added to their enteral feeds as soon as minimal feeding was introduced and continued for 28 days or until discharge.

RESULTS

With no adverse effects occurring, serum VA of the VA-supplemented infants on Days 14, 28, and postmenstrual 36 weeks was higher than that of the placebo group (P < 0.001). No signs of VA toxicity or increased intracranial pressure were reported. The VA group had lower unadjusted rates of Type 1 retinopathy of prematurity (1.6 vs. 6.9%, P = 0.030) and bronchopulmonary dysplasia (18.9 vs. 33.8%, P = 0.008) than the control group. Regression analysis revealed an association between serum VA levels and risk of Type 1 retinopathy of prematurity (beta = -2.37).

CONCLUSION

Vitamin A supplementation reduced VA deficiency in extremely preterm infants; it was associated with a decreased incidence of Type 1 retinopathy of prematurity and may also have a positive impact on reducing bronchopulmonary dysplasia.

Role of vitamin A supplementation in prevention of bronchopulmonary dysplasia in extremely low birth weight neonates: a systematic review of randomized trials

BACKGROUND

Bronchopulmonary dysplasia (BPD) is one of the most common consequence of extreme prematurity (<28 weeks of gestation). BPD affects approximately 55% of extremely low birth weight (ELBW) neonates.

AIMS

The aim of this systematic review is to evaluate the role of vitamin A supplementation in prevention of BPD in ELBW neonates.

METHOD

The literature search was done for various randomized control trial (RCT) by searching the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, EMBASE, and ongoing clinical trials.

RESULTS

This review included two RCTs that fulfilled inclusion criteria. There were statistically significant reduction in the incidence of BPD (oxygen requirement at 36 weeks of postmenstrual age (PMA)) (relative risk (RR) 0.88; 95%CI 0.77-0.99; p = .04; NNTB 14) and borderline significant reduction in combined outcomes of mortality/BPD (oxygen requirement at 36 weeks of PMA) (RR 0.90; 95%CI 0.82-1.00; p = .05). However, oxygen requirement at 28 days of life and combined outcome of mortality/BPD (oxygen requirement at 28 days of life) were not statistically significant.

CONCLUSIONS

The role of vitamin A supplementation in the prevention of BPD is supported by the current evidences. However, due to limited number of studies, current evidences are not sufficient which can translate into routine clinical practice. We need large high-quality trials, with sufficient power to reliably assess clinically relevant differences in outcomes.

Vitamin A Supplementation for the Prevention of Bronchopulmonary Dysplasia in Preterm Infants: An Update

Bronchopulmonary dysplasia (BPD) is a common complication of premature birth and is associated with significant morbidity. Vitamin A supplementation has been suggested as a potential preventative measure against BPD due to its role in lung maturation and because preterm infants are particularly predisposed to vitamin A deficiency. The aim of this review was to determine whether vitamin A supplementation reduces BPD risk among preterm infants. PubMed, CINAHL, and Web of Science databases were searched with the keywords "bronchopulmonary dysplasia," "vitamin A," and "preterm infants" and with the time frame of 2006-2016, and 4 studies were selected for review per the inclusion criteria. Only 1 study found a significant reduction in BPD risk associated with vitamin A supplementation; however, 2 studies indicated a nonsignificant benefit and may have been underpowered to show statistical significance. One study revealed an increased risk of sepsis associated with vitamin A supplementation (for infants weighing >1000 g at birth), but no risk was seen with vitamin A supplementation in the other studies. Because intramuscular vitamin A has shown benefit with minimal risk, continued supplementation for preterm infants is warranted. Future studies aimed at assessing infant groups that are most likely to benefit from supplementation (based on birth weight or other conditions), as well as determining the optimal dosing while minimizing injections, would be beneficial.

Vitamin A supplementation to prevent mortality and short- and long-term morbidity in very low birth weight infants

BACKGROUND

Vitamin A is necessary for normal lung growth and the integrity of respiratory tract epithelial cells. Preterm infants have low vitamin A status at birth and this has been associated with an increased risk of developing chronic lung disease.

OBJECTIVES

To evaluate supplementation with vitamin A on the incidence of death or neonatal chronic lung disease and long-term neurodevelopmental disability in very low birth weight (VLBW) infants compared with a control (placebo or no supplementation), and to consider the effect of the supplementation route, dose, and timing.

SEARCH METHODS

For the original review and subsequent updates, we searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library), MEDLINE, Science Citation Index, and the Oxford Database of Perinatal Trials. The reference lists of relevant trials, paediatric and nutrition journals, and conference abstracts and proceedings were handsearched up to 2010.For the 2016 update, we used the standard search strategy of the Cochrane Neonatal Review group to search the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 4), MEDLINE via PubMed (1 May 2016), EMBASE (1 May 2016), and CINAHL (1 May 2016). We also searched clinical trials' databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

Randomised controlled trials comparing vitamin A supplementation with a control (placebo or no supplementation) or other dosage regimens in VLBW infants (birth weight ≤ 1500 grams or less than 32 weeks' gestation).

DATA COLLECTION AND ANALYSIS

Two review authors screened the search results, extracted data, and assessed the trials for risk of bias. Results were reported as risk ratios (RR), risk differences (RD), and number needed to treat to benefit (NNTB), all with 95% confidence intervals (CI). Trialists were contacted for additional data.

MAIN RESULTS

Eleven trials met the inclusion criteria. Ten trials (1460 infants) compared vitamin A supplementation with a control and one (120 infants) compared different regimens of vitamin A supplementation. Compared to the control group, vitamin A appeared to have a small benefit in reducing the risk of death or oxygen requirement at one month of age (typical RR 0.93, 95% CI 0.88 to 0.99; typical RD -0.05, 95% CI -0.10 to -0.01; NNTB 20, 95% CI 10 to 100; 6 studies, 1165 infants) and the risk of chronic lung disease (oxygen requirement) at 36 weeks' postmenstrual age (typical RR 0.87, 95% CI 0.77 to 0.99; typical RD -0.07, 95% CI -0.13 to -0.01; NNTB 11, 95% CI 6 to 100; 5 studies, 986 infants) (moderate-quality evidence). There was a marginal reduction of the combined outcome of death or chronic lung disease (typical RR 0.92, 95% CI 0.84 to 1.01; typical RD -0.05, 95% CI -0.11 to 0.01; 4 studies, 1089 infants). Neurodevelopmental assessment of 88% of the surviving infants in the largest trial showed no difference between the groups at 18 to 22 months of age, corrected for prematurity (low-quality evidence). There is no evidence to support different vitamin A dosing regimens. No adverse effects of vitamin A supplementation were reported, but it was noted that intramuscular injections of vitamin A were painful.

AUTHORS' CONCLUSIONS

Whether clinicians decide to utilise repeat intramuscular doses of vitamin A to prevent chronic lung disease may depend upon the local incidence of this outcome and the value attached to achieving a modest reduction in the outcome balanced against the lack of other proven benefits and the acceptability of the treatment. Information on long-term neurodevelopmental status suggests no evidence of either benefit or harm from the intervention.

Should we still use vitamin A to prevent bronchopulmonary dysplasia?

Bronchopulmonary dysplasia (BPD) is associated with significant short- and long-term morbidity in preterm infants, and it can be prevented in some infants with vitamin A prophylaxis. Vitamin A, once widely used in neonatal intensive care, was scarce for the last few years, but has become available again at a much higher price, leading to dilemmas about its routine use. In this review we discuss experimental, clinical and socioeconomic evidence related to BPD, and provide a framework for clinicians and policy-makers to evaluate the value of vitamin A treatment and make decisions about its use for prevention of BPD.

Vitamin A Supplementation for Prevention of Bronchopulmonary Dysplasia: Cornerstone of Care or Futile Therapy?

OBJECTIVE

To review the evidence on vitamin A supplementation (VAS) and bronchopulmonary dysplasia (BPD) in extremely-low-birth-weight infants. We also discuss the impact of a vitamin A shortage on BPD rates.

DATA SOURCES

A PubMed search inclusive of dates 1946 to March 2016 was performed using the search terms bronchopulmonary dysplasia, chronic lung disease (CLD), and vitamin A STUDY SELECTION AND DATA EXTRACTION: All English-language studies were evaluated. Only those investigating VAS by intramuscular administration were included.

DATA SYNTHESIS

A total of 6 studies were evaluated. Additionally, a report on the incidence of BPD during a national shortage was reviewed. Investigators found mixed results with VAS and incidence of CLD or death in a varying number of neonates. In the largest evaluation, investigators found a statistically significant decrease in the rate of death or BPD: 55% in the VAS group versus 62% in the placebo group. The number needed to treat to prevent 1 case of BPD was 15 infants. Few studies found an increased incidence of adverse events following VAS. A report over a 2-year shortage period found that whereas the rate of VAS declined dramatically, BPD rates remained stable. This large observational evaluation calls into question the place of vitamin A in BPD prevention.

CONCLUSIONS

VAS has been identified as a strategy to decrease the incidence of BPD. Initial large-scale prospective evaluations have shown clear benefit of VAS in reducing the incidence of CLD or death. However, changing definitions of BPD and implementation of noninvasive ventilation strategies limit the application of early studies. During a drug shortage, VAS declined dramatically, but BPD rates remained stable. With concerns of sepsis and necrotizing enterocolitis in small-scale studies, and in light of the recent shortage evidence, further evaluations are necessary before VAS can be recommended as a cornerstone of BPD prevention.

[Vitamin A level and diseases of premature infants]

Vitamin A is a fat-soluble vitamin, and it is not only necessary for the normal growth and development of epithelial cells, but also plays a very important role in the normal growth and development of the retina, lungs, gastrointestinal tract, brain, and immune system. Studies have confirmed that the low level of vitamin A in premature infants at birth can last through the entire infancy. Recently, there have been particular concerns about the level of vitamin A and development of diseases in premature infants, with major focuses on the related mechanisms of action of vitamin A in respiratory distress syndrome, chronic lung disease, retinopathy of prematurity, necrotizing enterocolitis, patent ductus arteriosus, and infections in premature infants, which still awaits further investigation.This paper summarizes and analyzes the current status of research on vitamin A level and diseases of premature infants at home and abroad. In addition, although enough evidence suggests that vitamin A supplementation is beneficial to preterm infants, evidence is still lacking for recommended methods for supplementation and dose of vitamin A, and further studies are needed.

[Vitamin A level and diseases of premature infants]

Vitamin A is a fat-soluble vitamin, and it is not only necessary for the normal growth and development of epithelial cells, but also plays a very important role in the normal growth and development of the retina, lungs, gastrointestinal tract, brain, and immune system. Studies have confirmed that the low level of vitamin A in premature infants at birth can last through the entire infancy. Recently, there have been particular concerns about the level of vitamin A and development of diseases in premature infants, with major focuses on the related mechanisms of action of vitamin A in respiratory distress syndrome, chronic lung disease, retinopathy of prematurity, necrotizing enterocolitis, patent ductus arteriosus, and infections in premature infants, which still awaits further investigation.This paper summarizes and analyzes the current status of research on vitamin A level and diseases of premature infants at home and abroad. In addition, although enough evidence suggests that vitamin A supplementation is beneficial to preterm infants, evidence is still lacking for recommended methods for supplementation and dose of vitamin A, and further studies are needed.

Working group reports: evaluation of the evidence to support practice guidelines for nutritional care of preterm infants-the Pre-B Project

The "Evaluation of the Evidence to Support Practice Guidelines for the Nutritional Care of Preterm Infants: The Pre-B Project" is the first phase in a process to present the current state of knowledge and to support the development of evidence-informed guidance for the nutritional care of preterm and high-risk newborn infants. The future systematic reviews that will ultimately provide the underpinning for guideline development will be conducted by the Academy of Nutrition and Dietetics' Evidence Analysis Library (EAL). To accomplish the objectives of this first phase, the Pre-B Project organizers established 4 working groups (WGs) to address the following themes: 1) nutrient specifications for preterm infants, 2) clinical and practical issues in enteral feeding of preterm infants, 3) gastrointestinal and surgical issues, and 4) current standards of infant feeding. Each WG was asked to 1) develop a series of topics relevant to their respective themes, 2) identify questions for which there is sufficient evidence to support a systematic review process conducted by the EAL, and 3) develop a research agenda to address priority gaps in our understanding of the role of nutrition in health and development of preterm/neonatal intensive care unit infants. This article is a summary of the reports from the 4 Pre-B WGs.

Effectiveness of vitamin A in the prevention of complications of prematurity

BACKGROUND

To assess the effectiveness of vitamin A supplementation in very low birth weight (VLBW) infants to prevent complications of prematurity.

METHODS

This was a retrospective cohort study to determine the effectiveness of vitamin A in preventing complications of prematurity in VLBW infants. Vitamin A was delivered intramuscularly at a dose of 5000 IU, three times weekly during the first 28 days of life.

RESULTS

Of the 187 eligible VLBW infants, we excluded from the analysis (due to death or transfer to another hospital), 16 infants weighing <1000 g and 17 weighing 1000-1500 g. Sixty VLBW infants received the vitamin supplement. We observed no differences between the groups in the duration of oxygen therapy or in the risk of bronchopulmonary dysplasia. The risk of sepsis was up to three times higher among the infants who were given the vitamin A supplement.

CONCLUSION

Given the increased risk of sepsis in patients weighing >1000 g, the risk associated with repeated intramuscular injections of vitamin A and the modest clinical results described, we do not believe the universal administration of vitamin A to VLBW infants to be justified as prophylaxis for bronchopulmonary dysplasia.

Scientific, economic, regulatory, and ethical challenges of bringing science-based pediatric nutrition products to the U.S. market and ensuring their availability for patients

Many nutrition products and related drugs are unavailable or not consistently available to clinicians despite a body of clinical data and experience supporting their use. Many of these can be related to drug shortages that have increased since 2009. In addition, there are potentially useful products that are not approved for a specific use or are no longer being manufactured. This review broadly examines the product availability gap from the perspectives of a clinician/former nutrition industry medical director and an economist. The process of pediatric nutrition product and related drug innovation, as well as its drivers and the steps involved in bringing a product to market, is first described. This is followed by an assessment of factors influencing product availability beyond the innovation process, including regulatory issues, manufacturing compliance, purchasing practices, and other factors related to drug and nutrition product pricing and reimbursement. Three pediatric case examples are reviewed and placed in the context of the prior review. Last, recent and future possible steps toward closing the product availability gap are discussed.

Recent advances in late lung development and the pathogenesis of bronchopulmonary dysplasia

In contrast to early lung development, a process exemplified by the branching of the developing airways, the later development of the immature lung remains very poorly understood. A key event in late lung development is secondary septation, in which secondary septa arise from primary septa, creating a greater number of alveoli of a smaller size, which dramatically expands the surface area over which gas exchange can take place. Secondary septation, together with architectural changes to the vascular structure of the lung that minimize the distance between the inspired air and the blood, are the objectives of late lung development. The process of late lung development is disturbed in bronchopulmonary dysplasia (BPD), a disease of prematurely born infants in which the structural development of the alveoli is blunted as a consequence of inflammation, volutrauma, and oxygen toxicity. This review aims to highlight notable recent developments in our understanding of late lung development and the pathogenesis of BPD.