Bronchopulmonary Dysplasia

⚙

Pathophysiology

11

Preterm Birth with Saccular-Stage Lung and Surfactant Deficiency

The initiating condition is very preterm birth, which interrupts lung development in the canalicular/saccular stage before alveolarization. A lack of surfactant from incompletely differentiated alveolar type 2 cells leaves the immature lung unable to sustain gas exchange, so the infant requires supplemental oxygen and mechanical ventilation - the exposures that drive the downstream injury.

pulmonary alveolar type 2 cell CL:0002063

lung UBERON:0002048

Downstream

Hyperoxic Oxidative Lung Injury

Ventilator-Induced Lung Injury

Show evidence (1 reference)

PMID:31727986 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"a lack of pulmonary surfactant as a result of incomplete differentiation of AT2 cells causes RDS in preterm infants"

Ties the surfactant deficiency of this node to incomplete alveolar type 2 cell differentiation in the preterm lung.

Hyperoxic Oxidative Lung Injury

Supplemental oxygen exposes the immature, antioxidant-poor lung to hyperoxia, generating reactive oxygen species that injure alveolar epithelial and endothelial cells. It is one of the initial injuries that converge on pulmonary inflammation.

response to hyperoxia GO:0055093 ↑ INCREASED

lung UBERON:0002048

Downstream

Pulmonary Inflammation

Show evidence (1 reference)

PMID:31727986 SUPPORT INDIRECT REVIEW SYNTHESIS Human Clinical

"initial lung injury owing to surfactant deficiency, exposure to increased oxygen, mechanical ventilation, inadequate nutrition, infection and inflammation"

Names exposure to increased oxygen among the initial injuries to the preterm lung in BPD.

Ventilator-Induced Lung Injury

Mechanical ventilation of the structurally immature preterm lung causes volutrauma and stretch injury to the airways and distal airspaces, a second initial injury converging on inflammation. Preterm animal models show airway injury after even brief ventilation at birth.

lung UBERON:0002048

Animal models

Preterm lamb initiation-of-ventilation model Sheep recapitulates Brief initiation of ventilation in the preterm lamb reproduces the airway injury of mechanical ventilation.

Downstream

Pulmonary Inflammation

Show evidence (2 references)

PMID:19816239 SUPPORT DIRECT PRIMARY RESULT Model Organism

"We report where injury occurred within the lung after brief ventilation at birth."

Preterm sheep study demonstrating lung injury from initiating mechanical ventilation.

PMID:19816239 SUPPORT DIRECT BACKGROUND Human Clinical

"Premature infants exposed to ventilation are at risk of developing bronchopulmonary dysplasia and persistent lung disease in childhood."

States the clinical link between ventilation exposure and BPD risk that the model addresses.

Antenatal Inflammation (Chorioamnionitis)

Intrauterine inflammation, most often chorioamnionitis, primes the fetal lung before birth: it is both a cause of preterm birth and a gestation-independent contributor to BPD risk, and it blunts the surfactant response so that affected infants need longer mechanical ventilation. It feeds the same pulmonary inflammatory pathway as the postnatal injuries.

inflammatory response GO:0006954 ↑ INCREASED

Downstream

Pulmonary Inflammation

Show evidence (2 references)

PMID:24128984 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Antenatal inflammation with signs of a systemic fetal response reduces the response to exogenous surfactant in infants with respiratory distress syndrome, leading to a longer need for mechanical ventilation."

Links antenatal inflammation to a blunted surfactant response and longer ventilation, a route into the injury cascade.

PMID:24128984 SUPPORT INDIRECT REVIEW SYNTHESIS Human Clinical

"Multiple ante- and postnatal factors act in concert to injure the immature lung in the pathogenesis of the disease."

Frames BPD as a convergence of antenatal and postnatal injuries on the immature lung.

Postnatal Sepsis or Necrotizing Enterocolitis

Postnatal systemic inflammation from late-onset sepsis or necrotizing enterocolitis is a further inflammatory input that raises BPD risk, adding to the oxidative and mechanical injuries already acting on the lung.

Downstream

Pulmonary Inflammation

Show evidence (1 reference)

PMID:31727986 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Subsequent inflammation from sepsis or necrotizing enterocolitis can increase the risk of developing BPD."

Names postnatal sepsis and NEC as inflammatory inputs that increase BPD risk.

Pulmonary Inflammation

Inflammation is the common downstream pathway on which the oxidative, mechanical and antenatal injuries converge. Recruited neutrophils and macrophages and a proinflammatory cytokine milieu injure the developing lung and disrupt the growth-factor signaling that normal alveolar and vascular development depend on.

alveolar macrophage CL:0000583

inflammatory response GO:0006954 ↑ INCREASED

lung UBERON:0002048

Downstream

Disrupted VEGF Signaling

Arrested Alveolar Septation

Show evidence (2 references)

PMID:31727986 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Inflammation is the common pathway that initiates the lung injury that can progress to BPD."

Identifies pulmonary inflammation as the shared initiating pathway, the central effector of the cascade.

PMID:24128984 SUPPORT INDIRECT REVIEW SYNTHESIS Human Clinical

"Pulmonary inflammatory processes seen in animal models of chorioamnionitis resemble those seen in premature infants who developed BPD."

The pulmonary inflammation of BPD mirrors that triggered by chorioamnionitis, supporting the shared inflammatory node.

Disrupted VEGF Signaling

Injury and inflammation impair vascular endothelial growth factor (VEGF) signaling in the developing alveolar capillary endothelium. Restoring VEGF signaling in animal models of BPD preserves lung growth, which is the experimental basis for treating impaired VEGF signaling as a driver rather than a bystander.

lung endothelial cell CL:1001567

vascular endothelial growth factor signaling GO:0038084 ↓ DECREASED

lung UBERON:0002048

Downstream

Impaired Microvascular Growth

Show evidence (2 references)

PMID:29268623 SUPPORT DIRECT BACKGROUND Model Organism

"impaired VEGF signaling has been implicated in the pathogenesis of BPD"

Identifies impaired VEGF signaling as implicated in BPD pathogenesis.

PMID:29268623 SUPPORT INDIRECT PRIMARY RESULT Model Organism

"treatment with anti-sFlt-1 mAb preserves lung structure and function and prevents right ventricular hypertrophy in two rat models of BPD"

Restoring VEGF signaling with anti-sFlt-1 preserves lung growth, validating the signaling defect as causal by rescue.

Impaired Microvascular Growth

Disrupted VEGF signaling reduces and distorts the pulmonary microvasculature, leaving a sparse, dysmorphic capillary bed. By the vascular hypothesis of BPD, this early disruption of lung vascular growth also impairs growth of the distal airspace, coupling the vascular and alveolar lesions.

angiogenesis GO:0001525 ↓ DECREASED

lung UBERON:0002048

Animal models

Antenatal-stress rat BPD model (anti-sFlt-1 rescue) Rat rescues Anti-sFlt-1 mAb restores pulmonary vascular growth in antenatal-stress rat models of BPD, evidence that disrupted VEGF signaling drives the microvascular deficit.

Downstream

Arrested Alveolar Septation

Pulmonary Hypertension

Show evidence (1 reference)

PMID:31727986 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"early disruption of lung vascular growth and function can impair growth of the distal airspace"

States the vascular hypothesis, in which disrupted lung vascular growth impairs distal airspace (alveolar) growth.

Arrested Alveolar Septation

The defining lesion of the "new BPD" is disrupted alveolarization that leaves fewer, larger, simplified alveoli rather than the normal fine septation, reducing the gas-exchange surface. It is driven jointly by the inflammatory injury and by the impaired microvascular growth.

lung alveolus development GO:0048286 ↓ DECREASED

alveolus of lung UBERON:0002299

Animal models

Antenatal-stress rat BPD model (anti-sFlt-1 rescue) Rat rescues Anti-sFlt-1 mAb restores alveolar growth (radial alveolar count) in the same models, coupling the vascular rescue to alveolarization.

Downstream

Reduced Gas-Exchange Surface Area

Chronic pulmonary obstruction

Wheezing

Show evidence (1 reference)

PMID:31727986 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"BPD is a clinical syndrome of lung injury that disrupts alveolarization and microvascular development."

Defines BPD by disrupted alveolarization (arrested septation) together with microvascular disruption.

Reduced Gas-Exchange Surface Area

Simplified alveoli and a reduced capillary bed leave a lasting deficit of alveolar surface area for gas exchange. This is the functional endpoint that manifests as the persistent supplemental-oxygen requirement by which BPD is diagnosed at 36 weeks postmenstrual age.

lung UBERON:0002048

Downstream

Hypoxemia

Respiratory failure

Show evidence (1 reference)

PMID:31727986 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"result in a loss of alveolar surface area"

The converging injuries result in loss of alveolar surface area, the functional deficit of BPD.

Pulmonary Hypertension

The reduced, dysmorphic pulmonary microvasculature raises pulmonary vascular resistance, producing pulmonary hypertension and pulmonary vascular disease in a subset of infants, a strong contributor to mortality in BPD.

Downstream

Pulmonary arterial hypertension

Show evidence (1 reference)

PMID:31727986 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Pulmonary hypertension and related pulmonary vascular disease (PVD) have long been recognized as strong contributors to poor survival in preterm infants with BPD"

Establishes pulmonary hypertension/pulmonary vascular disease as a major BPD complication.

✶

Histopathology

1

Heterogeneous lung pathology

The BPD lung is heterogeneous, with regions of decreased alveolarization, cystic emphysema, fibrosis and variable airway injury.

Show evidence (1 reference)

PMID:31727986 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"including regions of decreased alveolarization, cystic emphysema, fibrosis and variable airway injury"

Describes the heterogeneous histopathology of the BPD lung.

⬡

Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.

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Phenotypes

6

Cardiovascular 1

Pulmonary arterial hypertension HP:0002092

Show evidence (1 reference)

PMID:31727986 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Prospective studies have provided echocardiographic evidence of pulmonary hypertension in 14-25% of preterm infants at 36 weeks post-menstrual age (PMA), with pulmonary hypertension especially prevalent (29-58%) in infants with severe BPD"

Quantifies pulmonary hypertension prevalence in preterm infants at 36 weeks PMA, synthesising several prospective cohorts.

Nervous System 1

Neurodevelopmental abnormality HP:0012759

Show evidence (1 reference)

PMID:31727986 SUPPORT INDIRECT REVIEW SYNTHESIS Human Clinical

"some clinical studies have suggested that BPD is an independent risk factor for poor neurodevelopmental outcomes, even in the absence of definite brain injuries, such as intraventricular haemorrhage or hypoxic ischaemic encephalopathy"

BPD is reported as an independent risk factor for poor neurodevelopmental outcomes.

Respiratory 4

Hypoxemia HP:0012418

Temporal: CHRONIC

Show evidence (1 reference)

PMID:31727986 SUPPORT INDIRECT REVIEW SYNTHESIS Human Clinical

"existing definitions (such as supplemental oxygen at 36 weeks PMA) predict poor outcome and continue to be useful in clinical practice to decrease the prevalence of BPD in NICUs"

The supplemental-oxygen requirement at 36 weeks PMA (chronic hypoxemia) is the defining criterion of BPD.

Respiratory failure HP:0002878

Show evidence (1 reference)

PMID:31727986 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"from persistent parenchymal lung disease and respiratory failure that is not attributable to other neonatal morbidities"

The most severe (grade 3A) BPD is defined by persistent parenchymal lung disease and respiratory failure.

Wheezing HP:0030828

Show evidence (1 reference)

PMID:31727986 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Symptoms of wheezing, cough, airway reactivity and shortness of breath are frequently encountered in this population"

Reports wheezing as a frequent respiratory symptom in the BPD population.

Chronic pulmonary obstruction HP:0006510

Show evidence (1 reference)

PMID:31727986 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Although obstructive lung disease is more commonly found in children with BPD than in those without BPD, restrictive lung disease can also be present"

Reports obstructive lung disease as more common in children with BPD.

🧬

Genetic Associations

1

Multifactorial genetic susceptibility

relationship_type: SUSCEPTIBILITY

Show evidence (1 reference)

PMID:31727986 SUPPORT INDIRECT REVIEW SYNTHESIS Human Clinical

"Genetic risk factors may also contribute to the development of BPD, as indicated by twin studies"

Twin studies indicate a heritable component to BPD susceptibility without naming a causative gene.

💊

Medical Actions

3

Caffeine Therapy

Action: Pharmacotherapy NCIT:C15986

Agent: caffeine CHEBI:27732

Platform: Small molecule

Caffeine, a respiratory stimulant, is the best-evaluated pharmacological treatment for reducing BPD risk; the Caffeine for Apnea of Prematurity (CAP) trial showed it reduces BPD and shortens ventilation and oxygen exposure.

Show evidence (2 references)

PMID:31727986 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Treatment with respiratory stimulants, such as caffeine, is the best-evaluated treatment for reducing BPD risk."

Caffeine is the best-evaluated treatment for reducing BPD risk.

PMID:31727986 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"The Caffeine for Apnea of Prematurity (CAP) trial demonstrated that caffeine administration reduces the risk of BPD and shortens the duration of ventilation with an endotracheal tube and exposure to supplemental oxygen"

The CAP randomized trial showed caffeine reduces BPD risk and ventilation/oxygen exposure.

Postnatal Corticosteroid Therapy

Action: Pharmacotherapy NCIT:C15986

Agent: corticosteroid CHEBI:50858

Platform: Small molecule

Corticosteroids given soon after birth decrease BPD incidence; the PREMILOC trial of early low-dose hydrocortisone improved survival without BPD in infants under 28 weeks of gestation. Benefit is weighed against neurodevelopmental risk.

Show evidence (3 references)

PMID:31727986 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Corticosteroids decrease the incidence of BPD when given soon after birth and prevent the progression of lung injury to BPD when given in the first weeks of life"

Corticosteroids given early decrease BPD incidence and progression.

PMID:31727986 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"the PREMILOC study compared the early use of 10 days of hydrocortisone therapy to placebo in 523 infants <28 weeks of gestation"

The PREMILOC trial tested early hydrocortisone, a corticosteroid, in very preterm infants.

PMID:31727986 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Concerns about adverse effects of these agents, such as neurodevelopmental impairment, mostly with dexamethasone, in the early 2000s led to recommendations against their use"

Backs the neurodevelopmental-risk caveat, which was raised mainly for dexamethasone.

Surfactant Replacement Therapy

Action: surfactant replacement therapy Ontology label: Pharmacotherapy NCIT:C15986

Platform: Protein replacement

Exogenous surfactant corrects the surfactant deficiency of the preterm lung; less-invasive surfactant administration (LISA) delivers it to infants managed on nasal CPAP without an endotracheal tube.

Show evidence (1 reference)

PMID:31727986 SUPPORT INDIRECT REVIEW SYNTHESIS Human Clinical

"A number of techniques have been developed for the delivery of surfactant to infants who are managed with NCPAP, including less-invasive surfactant administration (LISA)"

Describes surfactant delivery to preterm infants, including the LISA technique.

🌍

Environmental Factors

2

Supplemental oxygen therapy

Supplemental oxygen required to keep the preterm infant alive is also a clinical risk factor for BPD, acting through lung inflammation.

Show evidence (1 reference)

PMID:31727986 SUPPORT INDIRECT REVIEW SYNTHESIS Human Clinical

"Supplemental oxygen, positive pressure ventilation and postnatal sepsis, which all cause lung inflammation, are clinically associated with BPD."

Lists supplemental oxygen among the clinical exposures associated with BPD.

Mechanism Target:

TRIGGERS Hyperoxic Oxidative Lung Injury — Supplemental oxygen is the exposure that establishes hyperoxic oxidative injury in the immature lung.

Show evidence (1 reference)

PMID:31727986 SUPPORT INDIRECT REVIEW SYNTHESIS Human Clinical

"Supplemental oxygen, positive pressure ventilation and postnatal sepsis, which all cause lung inflammation, are clinically associated with BPD."

Supplemental oxygen is clinically associated with BPD through lung inflammation.

Mechanical ventilation (positive pressure)

Positive-pressure mechanical ventilation of the immature lung is a clinical risk factor for BPD, acting through lung inflammation and stretch injury.

Show evidence (1 reference)

PMID:31727986 SUPPORT INDIRECT REVIEW SYNTHESIS Human Clinical

"Supplemental oxygen, positive pressure ventilation and postnatal sepsis, which all cause lung inflammation, are clinically associated with BPD."

Lists positive pressure ventilation among the clinical exposures associated with BPD.

Mechanism Target:

TRIGGERS Ventilator-Induced Lung Injury — Positive-pressure ventilation is the exposure that produces ventilator-induced lung injury in the preterm lung.

Show evidence (1 reference)

PMID:31727986 SUPPORT INDIRECT REVIEW SYNTHESIS Human Clinical

"Supplemental oxygen, positive pressure ventilation and postnatal sepsis, which all cause lung inflammation, are clinically associated with BPD."

Positive pressure ventilation is clinically associated with BPD through lung inflammation.

🔬

Diagnosis

1

Clinical diagnosis at 36 weeks postmenstrual age

BPD is diagnosed clinically at 36 weeks postmenstrual age, historically a yes/no determination based on the need for supplemental oxygen; the 2001 and 2018 NICHD workshop definitions and the Jensen severity grades refine it.

Show evidence (1 reference)

PMID:31727986 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Although BPD is a 'yes/no' diagnosis at 36 weeks PMA, the term has become shorthand for the presence of respiratory morbidity in a preterm infant before and after discharge from hospital."

States the 36-week-PMA clinical diagnosis of BPD.

📈

Progression

2

Acute neonatal lung injury

In the neonatal period the preterm lung sustains oxidative, mechanical and inflammatory injury superimposed on surfactant deficiency.

Show evidence (1 reference)

PMID:31727986 SUPPORT INDIRECT REVIEW SYNTHESIS Human Clinical

"initial lung injury owing to surfactant deficiency, exposure to increased oxygen, mechanical ventilation, inadequate nutrition, infection and inflammation"

Describes the acute neonatal lung injury that initiates BPD.

Chronic airway and pulmonary vascular disease

Beyond the neonatal period, impaired lung development leaves persistent airway and pulmonary vascular disease that can affect adult lung function.

Show evidence (1 reference)

PMID:31727986 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"lung development is markedly impaired, which leads to persistent airway and pulmonary vascular disease that can affect adult lung function"

Describes the chronic phase of persistent airway and pulmonary vascular disease into adulthood.

📊

Prevalence

2

US extremely low gestational age newborns (ELGANs)

Birth Prevalence 35000.0 per 100,000 live births >1 in 1,000 (births)

Of ~50,000 ELGANs born each year in the USA, ~35% (18,000) develop BPD.

Show evidence (1 reference)

PMID:31727986 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Almost 50,000 ELGANs are born each year in the USA, and ~35% (18,000) of these children develop BPD."

Quantifies the share of US extremely low gestational age newborns who develop BPD.

Infants born at 22-24 weeks of gestation

Birth Prevalence 80000.0 per 100,000 live births >1 in 1,000 (births)

BPD risk is steeply gestational-age dependent - ~80% at 22-24 weeks versus ~20% at 28 weeks.

Show evidence (1 reference)

PMID:31727986 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Almost 80% of infants who are born at 22-24 weeks of gestation are diagnosed with BPD"

Quantifies BPD frequency at the lowest gestational ages.

⚖️

Clinical Burden

High

BPD carries high early-childhood respiratory morbidity, with up to half of affected children rehospitalized in the first two years of life.

Show evidence (1 reference)

PMID:31727986 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Up to 50% of children with BPD are rehospitalized during the first 2 years of life"

Quantifies the early-childhood rehospitalization burden of BPD.

🐁

Animal Models

2

Preterm lamb initiation-of-ventilation model

Preterm sheep ventilated briefly at birth, used to localize the airway and distal lung injury caused by initiating mechanical ventilation.

Species

Sheep

Publication

PMID:19816239

Pathograph links

Ventilator-Induced Lung Injury recapitulates fidelity: moderate observes: tissue Brief initiation of ventilation in the preterm lamb reproduces the airway injury of mechanical ventilation.

Limitations: A preterm sheep is not a human neonate, and the model captures the initial ventilation injury rather than the full chronic BPD phenotype.

Readouts

Bronchial epithelial disruption in medium-sized airways

Direction: INCREASED

Interpretation: Structural airway-injury correlate of the VILI node in this model.

Show evidence (1 reference)

PMID:19816239 SUPPORT PRIMARY RESULT Model Organism

"In both fetal and newborn lambs, ventilation caused bronchial epithelial disruption in medium-sized airways."

Reports the airway epithelial injury measured in the ventilated preterm sheep.

Show evidence (1 reference)

PMID:19816239 SUPPORT PRIMARY RESULT Model Organism

"Ventilation caused loss of heat shock protein 70 (HSP70) mRNA from the bronchial epithelium, but induced mRNA in the smooth muscle surrounding large airways."

A measured molecular injury signature from initiating ventilation, supporting the preterm sheep as informative for ventilator-induced lung injury.

Antenatal-stress rat BPD model (anti-sFlt-1 rescue)

Two antenatal-stress rat models of BPD in which an anti-sFlt-1 monoclonal antibody restores VEGF availability and rescues lung alveolar and vascular growth.

Species

Rat

Publication

PMID:29268623

Pathograph links

Impaired Microvascular Growth rescues fidelity: moderate observes: tissue Anti-sFlt-1 mAb restores pulmonary vascular growth in antenatal-stress rat models of BPD, evidence that disrupted VEGF signaling drives the microvascular deficit.

Limitations: Rat antenatal-stress models, and anti-sFlt-1 is an experimental intervention not in clinical use for BPD.

Readouts

Pulmonary vessel density

Direction: RESTORED

Interpretation: Anti-sFlt-1 therapy improved vessel density, the microvascular-growth readout.

Show evidence (1 reference)

PMID:29268623 SUPPORT PRIMARY RESULT Model Organism

"mAb therapy improved infant lung structure as assessed by radial alveolar count, vessel density, right ventricular hypertrophy, and lung function"

Reports improved vessel density with anti-sFlt-1 therapy.

Show evidence (1 reference)

PMID:29268623 SUPPORT PRIMARY RESULT Model Organism

"treatment with anti-sFlt-1 mAb preserves lung structure and function and prevents right ventricular hypertrophy in two rat models of BPD"

Supports treating this rat model as informative for the microvascular-growth node.

Arrested Alveolar Septation rescues fidelity: moderate observes: tissue Anti-sFlt-1 mAb restores alveolar growth (radial alveolar count) in the same models, coupling the vascular rescue to alveolarization.

Limitations: Same rat antenatal-stress models; radial alveolar count is a structural correlate of septation rather than septation itself.

Readouts

Radial alveolar count

Direction: RESTORED

Interpretation: Anti-sFlt-1 therapy improved radial alveolar count, an alveolarization readout.

Show evidence (1 reference)

PMID:29268623 SUPPORT PRIMARY RESULT Model Organism

"mAb therapy improved infant lung structure as assessed by radial alveolar count, vessel density, right ventricular hypertrophy, and lung function"

Reports improved radial alveolar count with anti-sFlt-1 therapy.

Show evidence (1 reference)

PMID:29268623 SUPPORT PRIMARY RESULT Model Organism

"treatment with anti-sFlt-1 mAb preserves lung structure and function and prevents right ventricular hypertrophy in two rat models of BPD"

Supports treating this rat model as informative for the alveolar-septation node.

{ }

Source YAML

click to show

name: Bronchopulmonary Dysplasia
creation_date: "2026-10-03T00:00:00Z"
category: Complex
synonyms:
- BPD
- chronic lung disease of prematurity
- neonatal chronic lung disease
description: >-
  Bronchopulmonary dysplasia is the chronic lung disease of prematurity. In a
  very preterm infant whose lungs are still in the saccular stage and deficient
  in surfactant, the supplemental oxygen and mechanical ventilation required to
  survive, together with pre- and postnatal inflammation, injure the immature
  lung and arrest its development. Inflammation is the shared downstream pathway;
  impaired VEGF-driven microvascular growth and arrested alveolar septation then
  produce the "new BPD" lesion of simplified, enlarged alveoli with a reduced,
  dysmorphic capillary bed. The result is a lasting loss of gas-exchange surface
  (oxygen dependence, diagnosed at 36 weeks postmenstrual age) and, in a subset,
  pulmonary vascular disease with pulmonary hypertension.
disease_term:
  preferred_term: bronchopulmonary dysplasia
  term:
    id: MONDO:0019091
    label: bronchopulmonary dysplasia
parents:
- respiratory system disorder
pathophysiology:
- name: Preterm Birth with Saccular-Stage Lung and Surfactant Deficiency
  role: trigger
  biological_scale: ORGANISM
  description: >-
    The initiating condition is very preterm birth, which interrupts lung
    development in the canalicular/saccular stage before alveolarization. A lack
    of surfactant from incompletely differentiated alveolar type 2 cells leaves
    the immature lung unable to sustain gas exchange, so the infant requires
    supplemental oxygen and mechanical ventilation - the exposures that drive the
    downstream injury.
  cell_types:
  - preferred_term: pulmonary alveolar type 2 cell
    term:
      id: CL:0002063
      label: pulmonary alveolar type 2 cell
  locations:
  - preferred_term: lung
    term:
      id: UBERON:0002048
      label: lung
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: DIRECT
    snippet: "a lack of pulmonary surfactant as a result of incomplete differentiation of AT2 cells causes RDS in preterm infants"
    explanation: Ties the surfactant deficiency of this node to incomplete alveolar type 2 cell differentiation in the preterm lung.
  downstream:
  - target: Hyperoxic Oxidative Lung Injury
    causal_link_type: DIRECT
  - target: Ventilator-Induced Lung Injury
    causal_link_type: DIRECT
- name: Hyperoxic Oxidative Lung Injury
  role: amplifier
  biological_scale: CELLULAR
  description: >-
    Supplemental oxygen exposes the immature, antioxidant-poor lung to
    hyperoxia, generating reactive oxygen species that injure alveolar
    epithelial and endothelial cells. It is one of the initial injuries that
    converge on pulmonary inflammation.
  biological_processes:
  - preferred_term: response to hyperoxia
    modifier: INCREASED
    term:
      id: GO:0055093
      label: response to hyperoxia
  locations:
  - preferred_term: lung
    term:
      id: UBERON:0002048
      label: lung
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: INDIRECT
    snippet: "initial lung injury owing to surfactant deficiency, exposure to increased oxygen, mechanical ventilation, inadequate nutrition, infection and inflammation"
    explanation: Names exposure to increased oxygen among the initial injuries to the preterm lung in BPD.
  downstream:
  - target: Pulmonary Inflammation
    causal_link_type: DIRECT
- name: Ventilator-Induced Lung Injury
  role: amplifier
  biological_scale: TISSUE
  description: >-
    Mechanical ventilation of the structurally immature preterm lung causes
    volutrauma and stretch injury to the airways and distal airspaces, a second
    initial injury converging on inflammation. Preterm animal models show airway
    injury after even brief ventilation at birth.
  locations:
  - preferred_term: lung
    term:
      id: UBERON:0002048
      label: lung
  evidence:
  - reference: PMID:19816239
    reference_title: "Airway injury from initiating ventilation in preterm sheep."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    quote_role: PRIMARY_RESULT
    directness: DIRECT
    snippet: "We report where injury occurred within the lung after brief ventilation at birth."
    explanation: Preterm sheep study demonstrating lung injury from initiating mechanical ventilation.
  - reference: PMID:19816239
    reference_title: "Airway injury from initiating ventilation in preterm sheep."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: BACKGROUND
    directness: DIRECT
    snippet: "Premature infants exposed to ventilation are at risk of developing bronchopulmonary dysplasia and persistent lung disease in childhood."
    explanation: States the clinical link between ventilation exposure and BPD risk that the model addresses.
  downstream:
  - target: Pulmonary Inflammation
    causal_link_type: DIRECT
- name: Antenatal Inflammation (Chorioamnionitis)
  role: trigger
  biological_scale: ORGANISM
  description: >-
    Intrauterine inflammation, most often chorioamnionitis, primes the fetal
    lung before birth: it is both a cause of preterm birth and a
    gestation-independent contributor to BPD risk, and it blunts the surfactant
    response so that affected infants need longer mechanical ventilation. It
    feeds the same pulmonary inflammatory pathway as the postnatal injuries.
  biological_processes:
  - preferred_term: inflammatory response
    modifier: INCREASED
    term:
      id: GO:0006954
      label: inflammatory response
  evidence:
  - reference: PMID:24128984
    reference_title: "Chorioamnionitis is essential in the evolution of bronchopulmonary dysplasia--the case in favour."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: DIRECT
    snippet: "Antenatal inflammation with signs of a systemic fetal response reduces the response to exogenous surfactant in infants with respiratory distress syndrome, leading to a longer need for mechanical ventilation."
    explanation: Links antenatal inflammation to a blunted surfactant response and longer ventilation, a route into the injury cascade.
  - reference: PMID:24128984
    reference_title: "Chorioamnionitis is essential in the evolution of bronchopulmonary dysplasia--the case in favour."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: INDIRECT
    snippet: "Multiple ante- and postnatal factors act in concert to injure the immature lung in the pathogenesis of the disease."
    explanation: Frames BPD as a convergence of antenatal and postnatal injuries on the immature lung.
  downstream:
  - target: Pulmonary Inflammation
    causal_link_type: DIRECT
- name: Postnatal Sepsis or Necrotizing Enterocolitis
  role: trigger
  biological_scale: ORGANISM
  description: >-
    Postnatal systemic inflammation from late-onset sepsis or necrotizing
    enterocolitis is a further inflammatory input that raises BPD risk, adding to
    the oxidative and mechanical injuries already acting on the lung.
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: DIRECT
    snippet: "Subsequent inflammation from sepsis or necrotizing enterocolitis can increase the risk of developing BPD."
    explanation: Names postnatal sepsis and NEC as inflammatory inputs that increase BPD risk.
  downstream:
  - target: Pulmonary Inflammation
    causal_link_type: DIRECT
- name: Pulmonary Inflammation
  role: central_effector
  biological_scale: CELLULAR
  description: >-
    Inflammation is the common downstream pathway on which the oxidative,
    mechanical and antenatal injuries converge. Recruited neutrophils and
    macrophages and a proinflammatory cytokine milieu injure the developing lung
    and disrupt the growth-factor signaling that normal alveolar and vascular
    development depend on.
  cell_types:
  - preferred_term: alveolar macrophage
    term:
      id: CL:0000583
      label: alveolar macrophage
  biological_processes:
  - preferred_term: inflammatory response
    modifier: INCREASED
    term:
      id: GO:0006954
      label: inflammatory response
  locations:
  - preferred_term: lung
    term:
      id: UBERON:0002048
      label: lung
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: DIRECT
    snippet: "Inflammation is the common pathway that initiates the lung injury that can progress to BPD."
    explanation: Identifies pulmonary inflammation as the shared initiating pathway, the central effector of the cascade.
  - reference: PMID:24128984
    reference_title: "Chorioamnionitis is essential in the evolution of bronchopulmonary dysplasia--the case in favour."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: INDIRECT
    snippet: "Pulmonary inflammatory processes seen in animal models of chorioamnionitis resemble those seen in premature infants who developed BPD."
    explanation: The pulmonary inflammation of BPD mirrors that triggered by chorioamnionitis, supporting the shared inflammatory node.
  downstream:
  - target: Disrupted VEGF Signaling
    causal_link_type: DIRECT
  - target: Arrested Alveolar Septation
    causal_link_type: DIRECT
- name: Disrupted VEGF Signaling
  role: effector
  biological_scale: CELLULAR
  description: >-
    Injury and inflammation impair vascular endothelial growth factor (VEGF)
    signaling in the developing alveolar capillary endothelium. Restoring VEGF
    signaling in animal models of BPD preserves lung growth, which is the
    experimental basis for treating impaired VEGF signaling as a driver rather
    than a bystander.
  cell_types:
  - preferred_term: lung endothelial cell
    term:
      id: CL:1001567
      label: lung endothelial cell
  biological_processes:
  - preferred_term: vascular endothelial growth factor signaling
    modifier: DECREASED
    term:
      id: GO:0038084
      label: vascular endothelial growth factor signaling pathway
  locations:
  - preferred_term: lung
    term:
      id: UBERON:0002048
      label: lung
  evidence:
  - reference: PMID:29268623
    reference_title: "Anti-sFlt-1 Therapy Preserves Lung Alveolar and Vascular Growth in Antenatal Models of Bronchopulmonary Dysplasia."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    quote_role: BACKGROUND
    directness: DIRECT
    snippet: "impaired VEGF signaling has been implicated in the pathogenesis of BPD"
    explanation: Identifies impaired VEGF signaling as implicated in BPD pathogenesis.
  - reference: PMID:29268623
    reference_title: "Anti-sFlt-1 Therapy Preserves Lung Alveolar and Vascular Growth in Antenatal Models of Bronchopulmonary Dysplasia."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    quote_role: PRIMARY_RESULT
    directness: INDIRECT
    snippet: "treatment with anti-sFlt-1 mAb preserves lung structure and function and prevents right ventricular hypertrophy in two rat models of BPD"
    explanation: Restoring VEGF signaling with anti-sFlt-1 preserves lung growth, validating the signaling defect as causal by rescue.
  downstream:
  - target: Impaired Microvascular Growth
    causal_link_type: DIRECT
- name: Impaired Microvascular Growth
  role: effector
  biological_scale: TISSUE
  description: >-
    Disrupted VEGF signaling reduces and distorts the pulmonary microvasculature,
    leaving a sparse, dysmorphic capillary bed. By the vascular hypothesis of
    BPD, this early disruption of lung vascular growth also impairs growth of the
    distal airspace, coupling the vascular and alveolar lesions.
  biological_processes:
  - preferred_term: angiogenesis
    modifier: DECREASED
    term:
      id: GO:0001525
      label: angiogenesis
  locations:
  - preferred_term: lung
    term:
      id: UBERON:0002048
      label: lung
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: DIRECT
    snippet: "early disruption of lung vascular growth and function can impair growth of the distal airspace"
    explanation: States the vascular hypothesis, in which disrupted lung vascular growth impairs distal airspace (alveolar) growth.
  downstream:
  - target: Arrested Alveolar Septation
    causal_link_type: DIRECT
  - target: Pulmonary Hypertension
    causal_link_type: DIRECT
- name: Arrested Alveolar Septation
  role: effector
  biological_scale: TISSUE
  description: >-
    The defining lesion of the "new BPD" is disrupted alveolarization that
    leaves fewer, larger, simplified alveoli rather than the normal fine
    septation, reducing the gas-exchange surface. It is driven jointly by the
    inflammatory injury and by the impaired microvascular growth.
  biological_processes:
  - preferred_term: lung alveolus development
    modifier: DECREASED
    term:
      id: GO:0048286
      label: lung alveolus development
  locations:
  - preferred_term: alveolus of lung
    term:
      id: UBERON:0002299
      label: alveolus of lung
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: DIRECT
    snippet: "BPD is a clinical syndrome of lung injury that disrupts alveolarization and microvascular development."
    explanation: Defines BPD by disrupted alveolarization (arrested septation) together with microvascular disruption.
  downstream:
  - target: Reduced Gas-Exchange Surface Area
    causal_link_type: DIRECT
  - target: Chronic pulmonary obstruction
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
  - target: Wheezing
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
- name: Reduced Gas-Exchange Surface Area
  role: consequence
  biological_scale: ORGANISM
  description: >-
    Simplified alveoli and a reduced capillary bed leave a lasting deficit of
    alveolar surface area for gas exchange. This is the functional endpoint that
    manifests as the persistent supplemental-oxygen requirement by which BPD is
    diagnosed at 36 weeks postmenstrual age.
  locations:
  - preferred_term: lung
    term:
      id: UBERON:0002048
      label: lung
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: DIRECT
    snippet: "result in a loss of alveolar surface area"
    explanation: The converging injuries result in loss of alveolar surface area, the functional deficit of BPD.
  downstream:
  - target: Hypoxemia
    causal_link_type: DIRECT
  - target: Respiratory failure
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
- name: Pulmonary Hypertension
  role: consequence
  biological_scale: ORGANISM
  description: >-
    The reduced, dysmorphic pulmonary microvasculature raises pulmonary vascular
    resistance, producing pulmonary hypertension and pulmonary vascular disease
    in a subset of infants, a strong contributor to mortality in BPD.
  notes: >-
    BPD-associated pulmonary hypertension is clinically classified as group 3
    (lung-disease-associated) pulmonary hypertension, not group 1 pulmonary
    arterial hypertension, despite the HP binding on the corresponding phenotype.
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: DIRECT
    snippet: "Pulmonary hypertension and related pulmonary vascular disease (PVD) have long been recognized as strong contributors to poor survival in preterm infants with BPD"
    explanation: Establishes pulmonary hypertension/pulmonary vascular disease as a major BPD complication.
  downstream:
  - target: Pulmonary arterial hypertension
    causal_link_type: DIRECT
phenotypes:
- name: Hypoxemia
  description: >-
    Chronic hypoxemia manifesting as the persistent supplemental-oxygen
    requirement that defines BPD at 36 weeks postmenstrual age.
  phenotype_term:
    preferred_term: Hypoxemia
    term:
      id: HP:0012418
      label: Hypoxemia
    temporality: CHRONIC
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: INDIRECT
    snippet: "existing definitions (such as supplemental oxygen at 36 weeks PMA) predict poor outcome and continue to be useful in clinical practice to decrease the prevalence of BPD in NICUs"
    explanation: The supplemental-oxygen requirement at 36 weeks PMA (chronic hypoxemia) is the defining criterion of BPD.
- name: Respiratory failure
  phenotype_term:
    preferred_term: Respiratory failure
    term:
      id: HP:0002878
      label: Respiratory failure
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: DIRECT
    snippet: "from persistent parenchymal lung disease and respiratory failure that is not attributable to other neonatal morbidities"
    explanation: The most severe (grade 3A) BPD is defined by persistent parenchymal lung disease and respiratory failure.
- name: Pulmonary arterial hypertension
  description: >-
    BPD-associated pulmonary hypertension / pulmonary vascular disease, present
    in a subset and most common in severe disease. Clinically group 3 pulmonary
    hypertension; see the Pulmonary Hypertension pathophysiology node notes.
  phenotype_term:
    preferred_term: Pulmonary hypertension
    term:
      id: HP:0002092
      label: Pulmonary arterial hypertension
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: DIRECT
    snippet: "Prospective studies have provided echocardiographic evidence of pulmonary hypertension in 14-25% of preterm infants at 36 weeks post-menstrual age (PMA), with pulmonary hypertension especially prevalent (29-58%) in infants with severe BPD"
    explanation: Quantifies pulmonary hypertension prevalence in preterm infants at 36 weeks PMA, synthesising several prospective cohorts.
- name: Wheezing
  description: >-
    Wheezing, cough and airway reactivity are frequent respiratory symptoms in
    children who had BPD.
  phenotype_term:
    preferred_term: Wheezing
    term:
      id: HP:0030828
      label: Wheezing
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: DIRECT
    snippet: "Symptoms of wheezing, cough, airway reactivity and shortness of breath are frequently encountered in this population"
    explanation: Reports wheezing as a frequent respiratory symptom in the BPD population.
- name: Chronic pulmonary obstruction
  description: >-
    Obstructive lung disease and chronic airflow limitation are more common in
    children who had BPD, with a concern for early-onset COPD in adult life.
  phenotype_term:
    preferred_term: Obstructive lung disease
    term:
      id: HP:0006510
      label: Chronic pulmonary obstruction
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: DIRECT
    snippet: "Although obstructive lung disease is more commonly found in children with BPD than in those without BPD, restrictive lung disease can also be present"
    explanation: Reports obstructive lung disease as more common in children with BPD.
- name: Neurodevelopmental abnormality
  description: >-
    BPD is reported as an independent risk factor for poor neurodevelopmental
    outcomes, even without overt brain injury. Left unconnected in the
    pathograph because the mechanism linking it to the lung disease is unsettled.
  phenotype_term:
    preferred_term: Neurodevelopmental abnormality
    term:
      id: HP:0012759
      label: Neurodevelopmental abnormality
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: INDIRECT
    snippet: "some clinical studies have suggested that BPD is an independent risk factor for poor neurodevelopmental outcomes, even in the absence of definite brain injuries, such as intraventricular haemorrhage or hypoxic ischaemic encephalopathy"
    explanation: BPD is reported as an independent risk factor for poor neurodevelopmental outcomes.
prevalence:
- population: US extremely low gestational age newborns (ELGANs)
  measure_type: BIRTH_PREVALENCE
  prevalence_class: ABOVE_1_IN_1000
  rate_per_100000: 35000.0
  rate_denominator: LIVE_BIRTHS
  notes: Of ~50,000 ELGANs born each year in the USA, ~35% (18,000) develop BPD.
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: DIRECT
    snippet: "Almost 50,000 ELGANs are born each year in the USA, and ~35% (18,000) of these children develop BPD."
    explanation: Quantifies the share of US extremely low gestational age newborns who develop BPD.
- population: Infants born at 22-24 weeks of gestation
  measure_type: BIRTH_PREVALENCE
  prevalence_class: ABOVE_1_IN_1000
  rate_per_100000: 80000.0
  rate_denominator: LIVE_BIRTHS
  notes: BPD risk is steeply gestational-age dependent - ~80% at 22-24 weeks versus ~20% at 28 weeks.
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: DIRECT
    snippet: "Almost 80% of infants who are born at 22-24 weeks of gestation are diagnosed with BPD"
    explanation: Quantifies BPD frequency at the lowest gestational ages.
diagnosis:
- name: Clinical diagnosis at 36 weeks postmenstrual age
  description: >-
    BPD is diagnosed clinically at 36 weeks postmenstrual age, historically a
    yes/no determination based on the need for supplemental oxygen; the 2001 and
    2018 NICHD workshop definitions and the Jensen severity grades refine it.
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: DIRECT
    snippet: "Although BPD is a 'yes/no' diagnosis at 36 weeks PMA, the term has become shorthand for the presence of respiratory morbidity in a preterm infant before and after discharge from hospital."
    explanation: States the 36-week-PMA clinical diagnosis of BPD.
genetic:
- name: Multifactorial genetic susceptibility
  relationship_type: SUSCEPTIBILITY
  notes: >-
    Twin studies indicate a heritable contribution to BPD risk, but no single
    causative gene is established; the search for genetic markers is ongoing. No
    gene term is bound because none is defensible as causative.
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: INDIRECT
    snippet: "Genetic risk factors may also contribute to the development of BPD, as indicated by twin studies"
    explanation: Twin studies indicate a heritable component to BPD susceptibility without naming a causative gene.
environmental:
- name: Supplemental oxygen therapy
  description: >-
    Supplemental oxygen required to keep the preterm infant alive is also a
    clinical risk factor for BPD, acting through lung inflammation.
  influences_mechanisms:
  - target: Hyperoxic Oxidative Lung Injury
    environmental_effect: TRIGGERS
    causal_link_type: DIRECT
    description: >-
      Supplemental oxygen is the exposure that establishes hyperoxic oxidative
      injury in the immature lung.
    evidence:
    - reference: PMID:31727986
      reference_title: "Bronchopulmonary dysplasia."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: REVIEW_SYNTHESIS
      directness: INDIRECT
      snippet: "Supplemental oxygen, positive pressure ventilation and postnatal sepsis, which all cause lung inflammation, are clinically associated with BPD."
      explanation: Supplemental oxygen is clinically associated with BPD through lung inflammation.
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: INDIRECT
    snippet: "Supplemental oxygen, positive pressure ventilation and postnatal sepsis, which all cause lung inflammation, are clinically associated with BPD."
    explanation: Lists supplemental oxygen among the clinical exposures associated with BPD.
- name: Mechanical ventilation (positive pressure)
  description: >-
    Positive-pressure mechanical ventilation of the immature lung is a clinical
    risk factor for BPD, acting through lung inflammation and stretch injury.
  influences_mechanisms:
  - target: Ventilator-Induced Lung Injury
    environmental_effect: TRIGGERS
    causal_link_type: DIRECT
    description: >-
      Positive-pressure ventilation is the exposure that produces
      ventilator-induced lung injury in the preterm lung.
    evidence:
    - reference: PMID:31727986
      reference_title: "Bronchopulmonary dysplasia."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: REVIEW_SYNTHESIS
      directness: INDIRECT
      snippet: "Supplemental oxygen, positive pressure ventilation and postnatal sepsis, which all cause lung inflammation, are clinically associated with BPD."
      explanation: Positive pressure ventilation is clinically associated with BPD through lung inflammation.
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: INDIRECT
    snippet: "Supplemental oxygen, positive pressure ventilation and postnatal sepsis, which all cause lung inflammation, are clinically associated with BPD."
    explanation: Lists positive pressure ventilation among the clinical exposures associated with BPD.
histopathology:
- name: Heterogeneous lung pathology
  description: >-
    The BPD lung is heterogeneous, with regions of decreased alveolarization,
    cystic emphysema, fibrosis and variable airway injury.
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: DIRECT
    snippet: "including regions of decreased alveolarization, cystic emphysema, fibrosis and variable airway injury"
    explanation: Describes the heterogeneous histopathology of the BPD lung.
treatments:
- name: Caffeine Therapy
  description: >-
    Caffeine, a respiratory stimulant, is the best-evaluated pharmacological
    treatment for reducing BPD risk; the Caffeine for Apnea of Prematurity (CAP)
    trial showed it reduces BPD and shortens ventilation and oxygen exposure.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: caffeine
      term:
        id: CHEBI:27732
        label: caffeine
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: DIRECT
    snippet: "Treatment with respiratory stimulants, such as caffeine, is the best-evaluated treatment for reducing BPD risk."
    explanation: Caffeine is the best-evaluated treatment for reducing BPD risk.
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: DIRECT
    snippet: "The Caffeine for Apnea of Prematurity (CAP) trial demonstrated that caffeine administration reduces the risk of BPD and shortens the duration of ventilation with an endotracheal tube and exposure to supplemental oxygen"
    explanation: The CAP randomized trial showed caffeine reduces BPD risk and ventilation/oxygen exposure.
- name: Postnatal Corticosteroid Therapy
  description: >-
    Corticosteroids given soon after birth decrease BPD incidence; the PREMILOC
    trial of early low-dose hydrocortisone improved survival without BPD in
    infants under 28 weeks of gestation. Benefit is weighed against
    neurodevelopmental risk.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: corticosteroid
      term:
        id: CHEBI:50858
        label: corticosteroid
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: DIRECT
    snippet: "Corticosteroids decrease the incidence of BPD when given soon after birth and prevent the progression of lung injury to BPD when given in the first weeks of life"
    explanation: Corticosteroids given early decrease BPD incidence and progression.
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: DIRECT
    snippet: "the PREMILOC study compared the early use of 10 days of hydrocortisone therapy to placebo in 523 infants <28 weeks of gestation"
    explanation: The PREMILOC trial tested early hydrocortisone, a corticosteroid, in very preterm infants.
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: DIRECT
    snippet: "Concerns about adverse effects of these agents, such as neurodevelopmental impairment, mostly with dexamethasone, in the early 2000s led to recommendations against their use"
    explanation: Backs the neurodevelopmental-risk caveat, which was raised mainly for dexamethasone.
- name: Surfactant Replacement Therapy
  description: >-
    Exogenous surfactant corrects the surfactant deficiency of the preterm lung;
    less-invasive surfactant administration (LISA) delivers it to infants managed
    on nasal CPAP without an endotracheal tube.
  therapeutic_modality: PROTEIN_REPLACEMENT
  notes: >-
    No therapeutic_agent term is bound - CHEBI has no term for pulmonary (lung)
    surfactant as a therapeutic preparation, and CHEBI:35195 "surfactant" is the
    generic surface-active-agent class (detergents), not this biological complex.
  treatment_term:
    preferred_term: surfactant replacement therapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: INDIRECT
    snippet: "A number of techniques have been developed for the delivery of surfactant to infants who are managed with NCPAP, including less-invasive surfactant administration (LISA)"
    explanation: Describes surfactant delivery to preterm infants, including the LISA technique.
progression:
- phase: Acute neonatal lung injury
  notes: >-
    In the neonatal period the preterm lung sustains oxidative, mechanical and
    inflammatory injury superimposed on surfactant deficiency.
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: INDIRECT
    snippet: "initial lung injury owing to surfactant deficiency, exposure to increased oxygen, mechanical ventilation, inadequate nutrition, infection and inflammation"
    explanation: Describes the acute neonatal lung injury that initiates BPD.
- phase: Chronic airway and pulmonary vascular disease
  notes: >-
    Beyond the neonatal period, impaired lung development leaves persistent
    airway and pulmonary vascular disease that can affect adult lung function.
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: DIRECT
    snippet: "lung development is markedly impaired, which leads to persistent airway and pulmonary vascular disease that can affect adult lung function"
    explanation: Describes the chronic phase of persistent airway and pulmonary vascular disease into adulthood.
clinical_burden:
  burden_level: HIGH
  rationale: >-
    BPD carries high early-childhood respiratory morbidity, with up to half of
    affected children rehospitalized in the first two years of life.
  evidence:
  - reference: PMID:31727986
    reference_title: "Bronchopulmonary dysplasia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: DIRECT
    snippet: "Up to 50% of children with BPD are rehospitalized during the first 2 years of life"
    explanation: Quantifies the early-childhood rehospitalization burden of BPD.
animal_models:
- name: Preterm lamb initiation-of-ventilation model
  species: Sheep
  publication: PMID:19816239
  description: >-
    Preterm sheep ventilated briefly at birth, used to localize the airway and
    distal lung injury caused by initiating mechanical ventilation.
  modeled_mechanisms:
  - target: Ventilator-Induced Lung Injury
    relationship: RECAPITULATES
    fidelity: MODERATE
    model_scale: TISSUE
    description: >-
      Brief initiation of ventilation in the preterm lamb reproduces the airway
      injury of mechanical ventilation.
    limitations: >-
      A preterm sheep is not a human neonate, and the model captures the initial
      ventilation injury rather than the full chronic BPD phenotype.
    readouts:
    - name: Bronchial epithelial disruption in medium-sized airways
      target: Ventilator-Induced Lung Injury
      direction: INCREASED
      interpretation: Structural airway-injury correlate of the VILI node in this model.
      evidence:
      - reference: PMID:19816239
        reference_title: "Airway injury from initiating ventilation in preterm sheep."
        supports: SUPPORT
        evidence_source: MODEL_ORGANISM
        quote_role: PRIMARY_RESULT
        snippet: "In both fetal and newborn lambs, ventilation caused bronchial epithelial disruption in medium-sized airways."
        explanation: Reports the airway epithelial injury measured in the ventilated preterm sheep.
    evidence:
    - reference: PMID:19816239
      reference_title: "Airway injury from initiating ventilation in preterm sheep."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      quote_role: PRIMARY_RESULT
      snippet: "Ventilation caused loss of heat shock protein 70 (HSP70) mRNA from the bronchial epithelium, but induced mRNA in the smooth muscle surrounding large airways."
      explanation: A measured molecular injury signature from initiating ventilation, supporting the preterm sheep as informative for ventilator-induced lung injury.
- name: Antenatal-stress rat BPD model (anti-sFlt-1 rescue)
  species: Rat
  publication: PMID:29268623
  description: >-
    Two antenatal-stress rat models of BPD in which an anti-sFlt-1 monoclonal
    antibody restores VEGF availability and rescues lung alveolar and vascular
    growth.
  modeled_mechanisms:
  - target: Impaired Microvascular Growth
    relationship: RESCUES
    fidelity: MODERATE
    model_scale: TISSUE
    description: >-
      Anti-sFlt-1 mAb restores pulmonary vascular growth in antenatal-stress rat
      models of BPD, evidence that disrupted VEGF signaling drives the
      microvascular deficit.
    limitations: >-
      Rat antenatal-stress models, and anti-sFlt-1 is an experimental
      intervention not in clinical use for BPD.
    readouts:
    - name: Pulmonary vessel density
      target: Impaired Microvascular Growth
      direction: RESTORED
      interpretation: Anti-sFlt-1 therapy improved vessel density, the microvascular-growth readout.
      evidence:
      - reference: PMID:29268623
        reference_title: "Anti-sFlt-1 Therapy Preserves Lung Alveolar and Vascular Growth in Antenatal Models of Bronchopulmonary Dysplasia."
        supports: SUPPORT
        evidence_source: MODEL_ORGANISM
        quote_role: PRIMARY_RESULT
        snippet: "mAb therapy improved infant lung structure as assessed by radial alveolar count, vessel density, right ventricular hypertrophy, and lung function"
        explanation: Reports improved vessel density with anti-sFlt-1 therapy.
    evidence:
    - reference: PMID:29268623
      reference_title: "Anti-sFlt-1 Therapy Preserves Lung Alveolar and Vascular Growth in Antenatal Models of Bronchopulmonary Dysplasia."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      quote_role: PRIMARY_RESULT
      snippet: "treatment with anti-sFlt-1 mAb preserves lung structure and function and prevents right ventricular hypertrophy in two rat models of BPD"
      explanation: Supports treating this rat model as informative for the microvascular-growth node.
  - target: Arrested Alveolar Septation
    relationship: RESCUES
    fidelity: MODERATE
    model_scale: TISSUE
    description: >-
      Anti-sFlt-1 mAb restores alveolar growth (radial alveolar count) in the
      same models, coupling the vascular rescue to alveolarization.
    limitations: >-
      Same rat antenatal-stress models; radial alveolar count is a structural
      correlate of septation rather than septation itself.
    readouts:
    - name: Radial alveolar count
      target: Arrested Alveolar Septation
      direction: RESTORED
      interpretation: Anti-sFlt-1 therapy improved radial alveolar count, an alveolarization readout.
      evidence:
      - reference: PMID:29268623
        reference_title: "Anti-sFlt-1 Therapy Preserves Lung Alveolar and Vascular Growth in Antenatal Models of Bronchopulmonary Dysplasia."
        supports: SUPPORT
        evidence_source: MODEL_ORGANISM
        quote_role: PRIMARY_RESULT
        snippet: "mAb therapy improved infant lung structure as assessed by radial alveolar count, vessel density, right ventricular hypertrophy, and lung function"
        explanation: Reports improved radial alveolar count with anti-sFlt-1 therapy.
    evidence:
    - reference: PMID:29268623
      reference_title: "Anti-sFlt-1 Therapy Preserves Lung Alveolar and Vascular Growth in Antenatal Models of Bronchopulmonary Dysplasia."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      quote_role: PRIMARY_RESULT
      snippet: "treatment with anti-sFlt-1 mAb preserves lung structure and function and prevents right ventricular hypertrophy in two rat models of BPD"
      explanation: Supports treating this rat model as informative for the alveolar-septation node.
datasets:

📚

References & Deep Research

Deep Research

1

Deep research results are used as seeds for research; they do not undergo the same validation as the main records and may contain errors. How we use deep research.

Evaluations and curation notes (1)

Create: Bronchopulmonary Dysplasia · 2026-10-03T23:41:25Z · View source

New complex-disorder entry for BPD (chronic lung disease of prematurity), MONDO:0019091. Modeled the multifactorial injury cascade: preterm saccular-stage surfactant-deficient lung plus antenatal inflammation (chorioamnionitis) as triggers; hyperoxic oxidative injury and ventilator-induced lung injury as amplifiers; pulmonary inflammation as the shared central effector converging on disrupted VEGF signaling/impaired microvascular growth and arrested alveolar septation (the 'new BPD' lesion), yielding reduced gas-exchange surface area and, in a subset, pulmonary hypertension. Four phenotypes (respiratory distress, chronic hypoxemia, respiratory failure, pulmonary arterial hypertension), all causally connected. 18 snippets verified against cache; all ontology terms (HP/GO/CL/UBERON/MONDO) confirmed by lookup. Evidence anchored on the Thebaud 2019 NRDP primer (PMID:31727986, graded REVIEW_SYNTHESIS), the chorioamnionitis debate piece (PMID:24128984), the anti-sFlt-1 rat rescue study (PMID:29268623, MODEL_ORGANISM) and the preterm-sheep ventilation-injury study (PMID:19816239, MODEL_ORGANISM). GeneReviews NO_CHAPTER (multifactorial, not Mendelian). The thin claude_code fallback DR report was used as a lead only; its single body PMID was off-topic and not cited.

Claude Code ▸

1. Disease Information

claude-haiku-4-5-20251001, claude-sonnet-5-5 4 citations 2026-10-03T23:30:24.439870

1. Disease Information

Overview. BPD is a chronic lung disease of prematurity. Injury to the immature lung, from oxygen, ventilation and inflammation, arrests alveolar and microvascular development ("alveolar simplification"). Thébaud 2019 frames it as an injury process occurring while the lung is still developing, then repairing and remodelling over months to years.

Identifiers - MONDO:0019091 (given in the template; verify). - ICD-10-CM P27.1 (BPD originating in the perinatal period). ICD-11 CA20.0, from memory, verify. - MeSH D001997. - OMIM: none, because the disease is multifactorial. Orphanet: not a rare Mendelian entry.

Synonyms. Chronic lung disease of prematurity (CLD); neonatal chronic lung disease; "old" (Northway) vs "new" BPD.

Definition history - Northway 1967 described classic BPD in ventilated, larger preterm infants. Its histology showed fibrosis, squamous metaplasia and airway injury. - NICHD 2001 (Jobe & Bancalari) defined BPD by oxygen need at 28 days, graded at 36 weeks postmenstrual age (PMA) as mild, moderate or severe. - NICHD 2018 (Higgins) and Jensen 2019 (an evidence-based definition) grade severity by respiratory support at 36 weeks PMA. Jensen 2019 is Grade 1 = nasal cannula ≤2 L/min, Grade 2 = >2 L/min or NIPPV/CPAP, Grade 3 = invasive ventilation, with a "2A/3A" early-death category. Grade boundaries are from memory.

Data source. Disease-level aggregate, not EHR-derived.

2. Etiology

Causal factors. BPD is multifactorial, with prematurity as the necessary background. The main drivers are: - Hyperoxia and oxidative stress. - Mechanical ventilation (volutrauma and barotrauma). - Antenatal and postnatal infection or inflammation (chorioamnionitis, sepsis). - Pulmonary insufficiency of prematurity and a patent ductus arteriosus (PDA).

Risk factors - Lower gestational age and birth weight are the dominant risk factors. - Fetal growth restriction, male sex, chorioamnionitis, postnatal sepsis and prolonged ventilation also raise risk. - Maternal smoking, preeclampsia and PDA are further associated factors. - Genetic risk: twin studies report high heritability (on the order of 50–80%). I recall Bhandari 2006 and Lavoie 2008, with no confident PMIDs. - GWAS have found no robust locus. - Candidate genes, such as SPINK1 and surfactant protein genes (SFTPB), are inconsistent. - Genetic note for curation: use relationship_type: SUSCEPTIBILITY or MODIFIER. Do not use CAUSATIVE.

Protective factors - Antenatal corticosteroids and female sex. - Caffeine (the CAP trial showed lower BPD). - Breast milk. - Gentle ventilation and noninvasive support.

Gene–environment interaction. Inferred rather than demonstrated: genetic susceptibility to oxidative injury, for example, interacts with hyperoxia exposure.

3. Phenotypes (HPO leads, verify)

Frequencies are not reliably sourced here. Reported BPD incidence depends on definition (see section 9).

Phenotype	HPO lead	Notes
Tachypnea	HP:0002789	Onset is neonatal; persists in severe BPD
Dyspnea / respiratory distress	HP:0002098	Neonatal; often worsens in the first weeks
Hypoxemia	HP:0012418	Oxygen dependence is the defining feature
Chronic lung disease / bronchopulmonary dysplasia	HP:0006528 or HP:0006529	Verify the correct term
Wheezing	HP:0030828	Common in infancy and childhood
Recurrent respiratory infections	HP:0002205	Common in the first 2 years
Pulmonary hypertension	HP:0002092	Complication in a subset
Failure to thrive	HP:0001508	Increased work of breathing and caloric needs
Abnormal lung CT / emphysema	not verified	Structural abnormality in survivors
Reduced FEV1	not verified	Persistent airflow obstruction into adulthood

Course. Onset is neonatal. Severity ranges from mild to severe. Symptoms improve with lung growth but can persist. Quality-of-life data are not retrieved in this report.

4. Genetic / Molecular Information

Causal genes: none established; BPD is non-Mendelian.
Susceptibility and modifier genes: inconsistent candidate-gene results. Surfactant genes (SFTPB, ABCA3 and SFTPC) cause interstitial lung disease in neonates and are differentials, not BPD causes.
Epigenetics: altered DNA methylation in cord blood and tracheal aspirates has been reported. This is not verified here.
Chromosomal abnormalities: none characteristic. FOXF1 and TBX4 variants mimic BPD with pulmonary hypertension.

5. Environmental Information

Environmental: supplemental oxygen (hyperoxia), mechanical ventilation, and postnatal steroids as a treatment confounder.
Lifestyle: maternal smoking in pregnancy.
Infectious agents: Ureaplasma species are associated with BPD. Causality is not demonstrated, and trials of azithromycin for Ureaplasma have been inconclusive.
ECTO leads (verify): hyperoxia exposure and tobacco-smoke exposure.

6. Mechanism / Pathophysiology

Causal chain (steps marked "inferred" are not directly demonstrated in humans)

Preterm birth interrupts the canalicular/saccular stages of lung development. The lung has surfactant deficiency and few alveoli.
This leads to respiratory failure requiring ventilation and oxygen.
Hyperoxia and ventilation produce oxidative stress and mechanical stretch injury of the epithelium.
Prenatal or postnatal infection and inflammation add cytokine signaling (IL-1β, IL-6, IL-8, TNF-α) and neutrophil/macrophage recruitment.
This leads to epithelial injury, apoptosis and disrupted growth-factor signaling, including VEGF, in the immature lung. The loss of VEGF signaling in the alveolar capillary network is inferred largely from animal models.
This leads to arrested alveolarization and impaired microvascular development, giving alveolar simplification, fewer and larger alveoli, and a dysmorphic capillary bed.
This leads to reduced gas-exchange surface area, causing chronic hypoxemia and oxygen dependence.
Branch A: vascular remodelling and raised pulmonary vascular resistance lead to pulmonary hypertension and right heart strain.
Branch B: airway smooth muscle hypertrophy and remodelling lead to airway hyperreactivity and wheeze.
Long-term, incomplete lung growth leads to persistent airflow obstruction in adulthood (COPD-like trajectory, inferred).

GO / CL leads (verify) - Processes: response to hyperoxia (GO:0055093), inflammatory response (GO:0006954), alveolar development (GO:0048286), angiogenesis (GO:0001525), apoptotic process (GO:0006915), response to oxidative stress (GO:0006979), extracellular matrix organization (GO:0030198). - Cells: type II pneumocyte (CL:0002063), pulmonary alveolar epithelial cell, lung endothelial cell, alveolar macrophage (CL:0000583), fibroblast (CL:0000057), airway smooth muscle cell (CL:0002062).

Molecular profiling. Not retrieved here. Check GEO for neonatal lung and tracheal-aspirate transcriptomics before adding a datasets: block. Per CLAUDE.md, run just verify-datasets and manually check disease relevance. Single-cell lung atlases of hyperoxia-injured neonatal mouse lung exist, but were not verified.

7. Anatomical Structures Affected

Primary: lung (UBERON:0002048), specifically the alveolus (UBERON:0002299) and the terminal airways and pulmonary vasculature.
Secondary: heart (right ventricle, via pulmonary hypertension); brain (neurodevelopmental effects in severe BPD); growth and nutrition.
Localization: bilateral and diffuse, with heterogeneous regional involvement on imaging.
Subcellular: mitochondria (oxidative stress) and the endoplasmic reticulum (surfactant protein handling); not verified.

8. Temporal Development

Onset: neonatal. The diagnosis is made at 36 weeks PMA (or at 28 days in the 2001 definition).
Stages: the acute neonatal injury phase, then a chronic phase with repair and remodelling over months to years (Thébaud 2019). Do not curate phases as separate entries; list them under progression:.
Course: most infants wean off oxygen in infancy, but a subset have severe disease with tracheostomy, home ventilation or pulmonary hypertension.
Critical periods: the first postnatal days (ventilation, oxygen and early caffeine) and the late-gestation window (antenatal steroids).

9. Inheritance and Population

Inheritance: multifactorial; no Mendelian pattern. Twin heritability is high.
Incidence and prevalence: about 40% of infants born before 28 weeks, and 10,000–15,000 new US cases annually (from memory). Because the figure depends on the definition used, record the definition with each rate: measure_type, rate_denominator: LIVE_BIRTHS, and the cohort in population. Verify against the NICHD Neonatal Research Network (Stoll et al.).
Demographics:
Affected infants are mostly those born extremely preterm; survival improvements have increased the number of survivors with BPD.
Boys are at higher risk.
Geographic variation reflects differences in NICU practice.

10. Diagnostics

Clinical criteria: NICHD 2001, NICHD 2018 and Jensen 2019 (see section 1), all based on respiratory support at 36 weeks PMA.
Imaging: chest X-ray (hazy lungs, cystic or fibrotic changes in classic BPD), lung ultrasound, and CT or MRI in selected cases.
Echocardiography: screen for pulmonary hypertension.
Functional tests: infant pulmonary function testing; later spirometry (reduced FEV1).
Biomarkers: research only, with no validated clinical biomarker. Candidates include cytokines and endostatin; not verified.
Genetic testing: not routine. Consider surfactant-gene and FOXF1/TBX4 testing in atypical or term-infant presentations.
Differential diagnosis: surfactant protein deficiency, ILD of infancy, pulmonary vascular disease, congenital heart disease and aspiration.
Screening: none for the disease itself. Risk stratification tools exist (the NICHD BPD outcome estimator); not verified.

11. Outcome / Prognosis

Mortality is higher in severe BPD (see Jensen 2019 for outcome by grade).
Survivors have more respiratory hospitalizations in early childhood, with persistent obstruction and reduced exercise capacity into adulthood.
Neurodevelopmental impairment is more frequent.
Complications include pulmonary hypertension, cor pulmonale, growth failure and airway malacia.
Prognostic factors: gestational age, severity grade, pulmonary hypertension and ventilator dependence.
No pooled survival numbers were verified for this report.

12. Treatment

NCIT treatment-term leads (verify): NCIT:C15986 (Pharmacotherapy), NCIT:C15747 (Supportive Care), NCIT:C15447 (Dietary Intervention).

Pharmacotherapy (prevention and treatment)
Caffeine citrate (CHEBI:27732, verify). The CAP trial (Schmidt 2006, PMID 16943402 unverified) showed a lower BPD rate. Search results note that earlier initiation seems more effective; a 2025 meta-analysis reported lower BPD but higher mortality with early caffeine.
Antenatal corticosteroids: strong evidence for preventing BPD.
Low-dose hydrocortisone in the first days prevents BPD but was associated with more late-onset sepsis in infants born at 24–25 weeks (search-result summary of the management review).
Postnatal dexamethasone has benefits and neurodevelopmental risks; the timing and dose tradeoffs were not verified.
Intramuscular vitamin A reduces BPD but is painful, expensive and not widely used.
Diuretics and inhaled bronchodilators help symptoms; the evidence for long-term benefit is weak.
Pulmonary hypertension: sildenafil, for which the evidence is limited.
Respiratory support: surfactant, less-invasive surfactant administration, noninvasive ventilation, volume-targeted ventilation, and oxygen saturation targeting.
Cell and gene therapy: mesenchymal stromal cell trials are in phase I/II. I do not have NCT numbers; search ClinicalTrials.gov and fetch each record before citing it.
Supportive: nutrition, growth support, infection avoidance and pulmonary rehabilitation.
Surgical: tracheostomy for prolonged ventilator dependence.

13. Prevention

Primary: prevention of preterm birth, antenatal corticosteroids, and avoidance of maternal smoking.
Respiratory strategy: gentle ventilation, noninvasive support, and early caffeine.
Tertiary: avoid respiratory infection (RSV prophylaxis, vaccination) and optimize growth.
Counseling: parental counseling about outcomes; not verified further.

14. Other Species / Natural Disease

Naturally occurring BPD is not established in other species. Preterm lambs and baboons are used experimentally (see section 15). NCBITaxon leads (verify): Ovis aries (NCBITaxon:9940), Papio (NCBITaxon:9554), Mus musculus (NCBITaxon:10090).

15. Model Organisms

Use the animal_models: section (not experimental_models), and link each model to a pathophysiology node via modeled_mechanisms with fidelity and limitations.

Hyperoxia-exposed neonatal rodents (mouse and rat). Postnatal hyperoxia gives alveolar simplification and impaired angiogenesis. Fidelity is limited because rodent lungs are saccular rather than alveolar at birth, so the developmental stage differs from that of a preterm human.
Preterm baboon (the 125-day, ventilated model), which reproduces "new BPD" most closely. Practical limits are cost and availability.
Preterm lamb. Similar fidelity strengths, with a larger-animal practical burden.
In vitro: lung organoids and iPSC-derived lung models, plus hyperoxia-exposed cell culture. Evidence source is IN_VITRO.
Genetic models: VEGF-pathway and related knockouts show the role of vascular signaling. The specific mouse lines and MGI identifiers were not verified.

Curation Cautions (CLAUDE.md-specific)

Granularity. Treat BPD as a single disease entry, with severity grades as has_subtypes or stages only if the sources support it. The "old/new BPD" split can be a note.
Genetic section. No causative genes; use susceptibility or modifier typing, and leave gene_disease_validity absent because no external classification exists.
Prevalence. Use structured Prevalence slots with measure_type and rate_denominator, not free text.
Evidence. Quote only from cached references after just fetch-reference. Grade evidence_source by the cited study type: rodent, baboon and lamb evidence is MODEL_ORGANISM.
Preterm-infant studies. These are HUMAN_CLINICAL; guideline or review statements may need quote_role: REVIEW_SYNTHESIS.
Causal wiring. Connect the phenotypes (hypoxemia, wheeze, pulmonary hypertension) to pathophysiology nodes with bare-name downstream targets.
Before the PR. Run just validate, just validate-terms, just count-verified-snippets, and just validate-disorders. Add a history/ record.

Gaps Not Covered by This Research

Verified PMIDs and abstract quotes for essentially every claim.
Frequencies for each phenotype.
Quality-of-life data.
Transcriptomic and proteomic datasets.
Clinical trial NCT identifiers.
A GeneReviews baseline. None is expected, since BPD is not Mendelian; confirm with just check-genereviews.

Sources - Thébaud et al. 2019, PMC6986462 - BPD: Pathogenesis and Pathophysiology - Evidence for the Management of BPD in Very Preterm Infants - Definitions review, Frontiers in Pediatrics 2023

Reference Validation

Checked with linkml-reference-validator 0.3.0rc3.

Outcome	Count
References checked	5
Resolved	5
Unresolved (possible confabulation)	0
Unverifiable	0
References weighed for topical relevance	5
On topic	4
Off topic	1

References that may not be about this subject

These identifiers resolve, so they are not fabrications, but the records they resolve to share almost none of this report's vocabulary. That is a clue and not a verdict - a paper can be relevant in ways its title and abstract do not spell out - so read them before deciding:

PMID:16943402 (1 mention) - A randomized trial of deep-brain stimulation for Parkinson's disease.
shared terms: disease

Weighed against this report's own most characteristic terms: bpd, verified, pulmonary, hypertension, disease, lung, preterm, ventilation, verify, respiratory, infant, growth, lead, neonatal, oxygen, definition, postnatal, support, surfactant, week.

All extracted references resolved successfully. Resolving is not the same as being relevant, though - see the references listed above as possibly off topic.

Term Validation

Checked with linkml-term-validator 0.4.5, through the ols: adapter.

Outcome	Count
Terms checked	30
Resolved	30
Unresolved (possible confabulation)	0
Obsolete	0
Unverifiable	0
Terms whose name was checked	14
Terms named correctly	8
Terms named as a different term	1
Terms whose name is worth a second look	5

Terms the report names something else

These identifiers resolve, so nothing about them looks wrong, and the ontology calls them something unrelated to what the report calls them. That usually means the identifier is not the one the sentence needs:

MONDO:0019091 (1 mention) - the report calls it "given in the template; verify"; MONDO calls it bronchopulmonary dysplasia

Terms whose name is worth a second look

The report's name for these is recognisably related to the term's own name without being one of them. A loose paraphrase reads the same way as a citation of the wrong sibling term - and so does a related synonym, which the ontology records precisely because it names something adjacent rather than the same thing - so these are listed rather than judged:

HP:0002098 (1 mention) - the report calls it "Dyspnea / respiratory distress"; HP calls it Respiratory distress
HP:0002092 (1 mention) - the report calls it "Pulmonary hypertension"; HP calls it Pulmonary arterial hypertension, and lists "Pulmonary artery hypertension" among its other names
GO:0055093 (1 mention) - the report calls it "Processes: response to hyperoxia"; GO calls it response to hyperoxia
CL:0002063 (1 mention) - the report calls it "Cells: type II pneumocyte"; CL calls it pulmonary alveolar type 2 cell, and lists "type II pneumocyte" among its other names
UBERON:0002048 (1 mention) - the report calls it "Primary: lung"; UBERON calls it lung**

Bronchopulmonary Dysplasia

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Environmental Factors

Diagnosis

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Prevalence

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Animal Models

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References & Deep Research

Deep Research

1. Disease Information

2. Etiology

3. Phenotypes (HPO leads, verify)

4. Genetic / Molecular Information

5. Environmental Information

6. Mechanism / Pathophysiology

7. Anatomical Structures Affected

8. Temporal Development

9. Inheritance and Population

10. Diagnostics

11. Outcome / Prognosis

12. Treatment

13. Prevention

14. Other Species / Natural Disease

15. Model Organisms

Curation Cautions (CLAUDE.md-specific)

Gaps Not Covered by This Research

Reference Validation

References that may not be about this subject

Term Validation

Terms the report names something else

Terms whose name is worth a second look