Different Patterns of Pulmonary Sequelae after Hyaline Membrane Disease: Heterogeneity of Bronchopulmonary Dysplasia?

Abstract

In an autopsy study of 37 infants who suffered from hyaline membrane disease (HMD), two distinct patterns of pulmonary lesions could be defined. One pattern, characterized by marked interstitial fibrosis in the absence of airway abnormalities, was labelled Ê»interstitial-type’ histology. A second type, labelled Ê»bronchiolar-type’ histology, showed marked airway lesions and alveolar emphysema. Nine patients of each type were analysed. Nineteen other patients had a Ê»mixed-type’ histology and were not further studied. Retrospectively, the clinical and radiological characteristics of both series were analysed. No differences in birth weight, gestational age and initial radiological HMD grade could be demonstrated. The pulmonary function of the bronchiolar-type patients however was significantly worse at the onset, and these infants needed more oxygen and ventilatory support during the first 10 days of life. They all died from respiratory failure whereas 4 patients from the interstitial group had non-pulmonary fatalities. In the bronchiolar group chest X-rays showed atelectasis and pulmonary interstitial emphysema in the early stages, and hyperinflation with bullae and irregular streaky densities in the later. Patients in the interstitial group had no or minor emphysema with more homogeneously spread densities over both lungs. We conclude that both types of evolution represent two extremes of the bronchopulmonary dysplasia spectrum.

Prolonged mechanical ventilation with air induces apoptosis and causes failure of alveolar septation and angiogenesis in lungs of newborn mice

“…This study shows for the first time that prolonged MV of the developing lung with air, without associated hyperoxia, inhibits alveolar septation and angiogenesis and is associated with increased apoptosis, activation of TGF␤, and reduced expression of VEGF-R2, a critical determinant of normal lung development. These structural and molecular changes that occurred in newborn mice after 24 h of positive-pressure MV are similar to changes that have been described in newborn infants with CLD (8,15,28,29,43,67) and in authentic animal models of this disease (2,12,18,42).…”

Role of matrix metalloprotease-9 in hyperoxic injury in developing lung

“…An increase in alveolar size with fewer alveoli was found in postmortem specimens of surfactant-treated subjects by Husain et al (25) in which the MLI was significantly increased in BPD subjects compared with non-BPD. Hislop et al (23) and others (6,44) have shown that the lungs of preterm infants who received mechanical ventilation and oxy- . Quasistatic compliance (Qst) from anesthetized 13-day-old WT and MMP-9 (Ϫ/Ϫ) pups after 8 days of hyperoxia or room air exposure measured by forced oscillation technique.…”

Impact of Improved Survival of Very Low-Birth-Weight Infants on Incidence and Severity of Bronchopulmonary Dysplasia

“…Third, one of the histological hallmarks of BPD, i.e. severe airway injury, is now less frequently observed [23,24], and interstitial fibroproliferation and decreased alveolarization now predominate [25][26][27]. These features appear to be associated clinically with milder degrees of chronic respiratory distress.…”