Iodide transporters expression in early human invasive trophoblast.

The placenta plays an essential role in the fetomaternal exchanges of iodine and thyroid hormones. Propylthiouracil (PTU) is presently considered to be the treatment of choice for hyperthyroidism during the first trimester of pregnancy. Little is known on the expression of iodide transporters in invasive human trophoblast and the possible effect of PTU on this early phase of human placental development. To analyze during early pregnancy expression of sodium/iodide symporter (NIS) and pendrin at the feto-maternal interface in situ in first trimester placentas, in vitro during human trophoblastic cell differentiation in presence or not of PTU. NIS and pendrin immunodetection were performed on 8-10 WG placental tissue sections and in primary cultures of first trimester placenta trophoblastic cells, which differentiate in vitro into syncytiotrophoblast or invasive extravillous cytotrophoblasts (EVCT). The effect of PTU (1 mM) was tested in EVCT on iodide transporters expression, cell invasion, and hCG secretion. NIS and pendrin were present in early human trophoblast at the maternofetal interface. Their expression was modulated with in vitro trophoblast differentiation. Early invasive EVCT were characterized by higher expression of NIS than pendrin. In vitro PTU did modify significantly neither EVCT iodide transporters expression nor EVCT biological functions: i.e. invasive properties and hCG secretion. This study reveals that NIS is highly expressed in early human trophoblast at the feto-maternal interface. PTU has no effect on early human trophoblast invasion.