Tissue interactions mediate early events in pulmonary vasculogenesis.

摘要: Extensive study has provided considerable insight into the mechanisms governing branching morphogenesis and developmental maturation of pulmonary epithelium. The process by which vascular tree arises in mesodermal mesenchyme developing lung, however, is not known. Because normal epithelial differentiation have been shown to be dependent on interactions with lung mesenchyme, we hypothesized that vasculature a reciprocal interaction In this defined temporal spatial expression flk-1 mRNA, encodes an endothelial cell-specific growth factor (VEGF) receptor, fetal neonatal rat lung. Flk-1-positive cells were observed at every prenatal stage from day 11 through birth, demonstrating vascularization initiated as soon evaginates foregut distribution precursors was distinct consistent early (fetal days 11-16): clusters flk-1-positive localized closely apposed This relationship between epithelium suggested development may two tissue types. To investigate possibility, day-13 distal cultured presence absence Lung degenerated significantly, few maintained. contrast, recombined contained abundant cells, their mimicked vivo. These studies provide first detailed information regarding pattern suggest play important role maintenance vasculature.