Chorioamnionitis, postnatal factors and proinflammatory response in the pathogenetic sequence of bronchopulmonary dysplasia.

Pulmonary inflammation has a central role in the multifactorial and complex pathogenesis of bronchopulmonary dysplasia. Pre- and postnatal factors such as chorioamnionitis, oxygen toxicity, mechanical ventilation and postnatal infections can induce and perpetuate an injurious and complex inflammatory response in the airways and lung tissue of very immature infants. This inflammatory process is characterized by the accumulation of inflammatory cells and an arsenal of proinflammatory mediators such as cytokines, toxic oxygen radicals, lipid mediators and potent proteases. An imbalance between pro- and anti-inflammatory factors favoring the proinflammatory process can be considered as a hallmark of lung injury. In addition, impaired mechanisms of tissue remodeling and repair together with a subnormal generation of growth factors could affect alveolarization and vascular development with lifelong consequences for the infants with bronchopulmonary dysplasia.