Differential release of prostaglandins by organ cultures of human fetal trachea and lung

Differential response of the epithelium and interstitium in developing human fetal lung explants to hyperoxia

Hyperoxia is closely linked with the development of chronic lung disease of prematurity (CLD), but the exact mechanisms whereby hyperoxia alters the lung architecture in the developing lung remain largely unknown. We developed a fetal human lung organ culture model to investigate (a) the morphologic changes induced by hyperoxia and (b) whether hyperoxia resulted in differential cellular responses in the epithelium and interstitium. The effects of hyperoxia on lung morphometry were analyzed using computer-assisted image analysis. The lung architecture remained largely unchanged in normoxia lasting as long as 4 d. In contrast, hyperoxic culture of pseudoglandular fetal lungs resulted in significant dilatation of airways, thinning of the epithelium, and regression of the interstitium including the pulmonary vasculature. Although there were no significant differences in Ki67 between normoxic and hyperoxic lungs, activated caspase-3 was significantly increased in interstitial cells, but not epithelial cells, under hyperoxic conditions. These changes show that exposure of pseudoglandular lungs to hyperoxia modulates the lung architecture to resemble saccular lungs.

Maternal and feto-placental prostanoid responses to a single course of antenatal betamethasone

We tested the hypothesis that antenatal betamethasone alters prostanoid levels in the maternal and feto-placental compartments. Forty-three singleton pregnancies were studied. Group I were women treated with a single course of antenatal betamethasone and who delivered <37 weeks gestation; Group II were untreated women who delivered <37 weeks; and Group III were untreated women who delivered >38 weeks. Maternal and mixed cord blood; and placental samples were collected at delivery and analyzed for PGE2, PGF(2alpha), 6-ketoPGF(1alpha), and TxB2 levels. Antenatal betamethasone decreased maternal PGE2 levels with concomitant increases in the feto-placental compartment. Umbilical cord TxB2 levels in the treated group were significantly lower than the non-treated pre-term and term groups resulting in a higher 6-ketoPGF(1alpha):TxB2 ratio. Considering the regulatory role of PGE2 and PGI2 in fetal lung development and neonatal transition homeostasis, these results suggest a mechanism, at least in part, for the beneficial effects of antenatal steroids on fetal lung maturation and neonatal cardio-pulmonary homeostasis at birth.