Article The Rockefeller University Press $30.00

The most dramatic physiological change associ-ated with birth is the onset of respiration. Mam-mals must breathe within minutes of birth to deliver oxygen to the brain and other organs, yet the lungs develop in a fluid environment and do not function until the time of birth. Successful neonatal respiration requires a complex prenatal lung maturation program that prepares the lung for air inflation and gas exchange at birth. A key aspect of this preparation is mechanical, i.e., in-creasing the compliance of the lung so that it can be successfully inflated at the time of birth (Guyton and Hall, 2000). A known regulator of pulmonary compliance is surfactant, a lipopro-tein mixture produced in the late gestation lung that increases lung compliance by reducing al-veolar surface tension (Avery and Mead, 1959; Adams et al., 1965; Morgan, 1971). The impor-tance of prenatal lung maturation in neonatal respiration is revealed by the high incidence of respiratory failure, termed respiratory distress syn-drome (RDS), among infants born before 29 wk of gestation (Hintz et al., 2005). Surfactant ad-ministration improves pulmonary compliance and RDS mortality (Couser et al., 1990), but pre-mature infants still require supportive care such as oxygen and mechanical ventilation that are as-sociated with long-term complications (Hintz et al., 2005; Suresh and Soll, 2005). The identifi-cation of additional mechanical aspects of lung maturation that may contribute to the patho-genesis of RDS is necessary to more effectively treat this common disease