[Expression of cell adhesion molecules in the extravillous trophoblast in placentas of preterm pregnancies and in placentas at term].

Invasion of the human trophoblast is regulated by cell adhesion molecules (CAM) such as integrins and members of the immunoglobulin superfamily, which also play an important role in a number of immunological reactions. Abnormal trophoblast invasion of the uterus and its arterial system has been related to preterm delivery. We examined the differences of CAM expression in the extravillous trophoblast of preterm (n = 18) and term pregnancies (n = 21). Placenta and decidua frozen sections were examined by double-staining immunohistochemistry using antibodies against the immunoglobulin superfamily (ICAM-1, ICAM-2, ICAM-3, VCAM-1), integrins (alpha 2 beta 1, alpha 3 beta 1, alpha 4 beta 1, alpha 5 beta 1, alpha 6 beta 1) and cytokeratin. The percentage of immunopositive extravillous trophoblast cells and the intensity of immunoreactivity for the mentioned CAM antibodies was assessed. The expression of alpha 3 beta 1, alpha 5 beta 1 and VCAM-1 (p < 0.05) in the extravillous trophoblast of preterm placentas was lower than in normal placentas, whereas the expression of alpha 6 beta 1 in the extravillous trophoblast of preterm placentas was higher than at term (p < 0.05). No differences were observed for alpha 2 beta 1, alpha 4 beta 1, ICAM-1, ICAM-2 and ICAM-3. Our results show that there is a different expression of cell adhesion molecules in the extravillous trophoblast of placentas in preterm delivery. These differences in CAM might be associated with abnormal immunological and cell-cell interactions between mother and developing fetus and thus cause preterm labor and delivery.