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Keywords:

  • ET-1;
  • immunohistochemistry;
  • fetal membranes;
  • placenta;
  • labor

PROBLEM: The aim of the study was to determine the ET-1 localization on human placenta and fetal membranes and to compare its distribution between term and preterm pregnancies in laboring and non-laboring tissues.

METHODS: Tissues obtained from nine term elective cesarean section, eight spontaneous vaginal term delivery, and 13 preterm delivery from both cesarean section (N = 6) and vaginal delivery (N = 7) were studied by immunohistochemistry.

RESULTS: Immunoreactive ET-1 (IR-ET-1) was detected in villous and nonvillous trophoblast in all groups, although laboring tissues showed strong staining in the syncytiotrophoblast of the villi. ET-1 immunostaining of endothelial cells was observed in all placental villous vessels with a considerable variability within groups. In the fetal membranes, intensive immunopositive staining was observed in the chorionic trophoblast following vaginal deliveries in term and preterm tissues.

CONCLUSIONS: This is the first study to report the localization of IR-ET-1 in human fetal membranes and placenta, and suggests that amnion and trophoblast represents a source of ET-1 production or, alternatively, a site for ET-1 binding.