According to an animal model of intrauterine growth restriction induced by maternal nutritional restriction (also known as another BPD model), IGF-1 expression is decreased, and intrinsic-pulmonary IGF-I signaling is suppressed during the fetal and early neonatal periods; however, during the later catch-up growth phase, both IGF-I and IGF-I signaling are elevated, and septal thickness, matrix deposition, and increased expression of vimentin and collagen Iα1 are observed due to the activation of myofibroblasts50. This evidence concerns the gene IGF1 and bronchopulmonary dysplasia.