ELN and bronchopulmonary dysplasia: Despite the catch-up of structural lung development (relative to body weight), lung function on corrected day 4 was significantly affected with altered tissue mechanics, dynamic compliance and elastance It is unclear whether this relates to the marked but ambiguous dysregulation of elastin mRNA-expression (which is reminiscent of changes in elastic tissue in tissue from infants with BPD [23]) or to the (possibly compensatory) upregulation of surfactant protein mRNA-expression.