Expression of matrix metalloproteinases 2 and 9 in human trophoblasts of normal and preeclamptic placentas: Preliminary findings

Objective: Here we test the hypothesis that “the expression of matrix metalloproteinase 2 and 9 proteins is altered in preeclamptic placentas compared to placentas of normal pregnancy.”Patients and methods: This case–control study includes preeclamptic placentas (40 women with preeclampsia) from a singleton pregnancy and placentas of normal pregnancies (control group, 40 women with uncomplicated pregnancy). The expression patterns of metalloproteinases 2 and 9 were examined using immunohistochemical staining methods.Results: Compared to uncomplicated pregnancy, the incidence of intrauterine growth restriction was high and the mean birth weight was markedly low in patients with preeclampsia. Both metalloproteinase 2 and 9 proteins were frequently and strongly expressed in the majority of placentas of uncomplicated pregnancies (control group). Metalloproteinase 9 expression was absent in the majority of the preeclamptic placentas. In the remaining cases of preeclamptic placentas, the expression of metalloproteinase 9 was weak. In contrast, a strong metalloproteinase 2 protein expression was seen in the majority of the preeclamptic placentas.Conclusions: These preliminary data demonstrate the expression of metalloproteinase 2 and 9 proteins in the placentas of uncomplicated pregnancies. The absence/reduced expression of metalloproteinase 9 in the preeclamptic placentas may be related to insufficient invasion of trophoblast, leading to superficial and unsuccessful placentation.