A novel in vitro model of trophoblast-mediated decidual blood vessel remodeling.

In vivo the extravillous trophoblasts (EVTs) penetrate the decidua and the first third of the myometrium to remodel the uterine spiral arteries and achieve the high-flow, low-resistance circulation characteristic of the intervillous space of the term placenta. Much of our understanding of these processes comes from histologic analysis of placental bed biopsies, a limited tissue source and one that can provide only a snapshot of a dynamic process. To better characterize these cellular interactions, we have developed an in vitro co-culture system in which first trimester villous explants are cultured at low oxygen tension in contact with 2-mm(2) sections of decidua parietalis from the same patient.