However, it is of note that IPY development is strictly regulated in such a way that columnar epithelium and squamous epithelium face the chorion layer and labyrinthine layer, respectively. Since PDGFRa is expressed in both types of epithelium, PDGFRa alone could not establish such an organization, suggesting that another molecule is required for correct placement of epithelium during PDGFRa-dependent proliferation and invagination. ventolin inhaler
Since the rapid growth of all of the placental components is an integral part in the formation of a functional materno-fetal transport system, a defect in one component may result in the developmental and functional failure of the entire placental system. The presence of the IPY has been almost disregarded in many studies on the murine placenta. Since it is also an integral part of the murine placenta and its development is regulated by the cytokine network in the placenta, we want to emphasize that more attention should be paid to IPY development. Recently, defective placental formation has been reported in mice with such mutations as null mutation of epidermal growth factor, HGF/SF, VCAM-1, and Wnt2 genes. Reevaluation of IPY formation in these mice may provide insight into the molecular mechanism not only for the IPY but also for the entire placental development.