EICOSANOID BIOSYNTHETIC-ENZYMES IN PLACENTAL AND DECIDUAL TISSUES FROM PREECLAMPTIC PREGNANCIES - INCREASED EXPRESSION OF THROMBOXANE-A2 SYNTHASE GENE

Preeclampsia is a disease of late pregnancy characterized by hypertension, edema, and proteinuria, in which vasoconstriction, platelet aggregation, and reduced uteroplacental blood flow contribute to preterm delivery, perinatal morbidity, and mortality. Increased thromboxane-A(2) (TXA(2)) and/or decreased prostacyclin (PGI(2)) have been implicated as causative factors of this disease. The present studies investigated the expression of TXA(2) synthase gene along with those of TXA(2) receptors, PGI(2) synthase, cyclooxygenase-1 (COX-1), and COX-2 in placental and decidual tissue from preeclamptic and normal pregnancies. In situ. hybridization and immunocytochemistry showed that primarily trophoblast layer and decidual cells express TXA(2) synthase, COX-1, and COX-2 enzymes. Immunocytochemistry for PGI(2) synthase and in situ hybridization for TXA(2) receptors showed similar results. Trophoblast layer and decidua from preeclamptic pregnancies contained a greater abundance of mRNA and protein of TXA(2) synthase than the matched normal pregnancies. In summary, our findings suggest that an increased local expression of TXA(2) synthase could be responsible for local and/or peripheral vascular changes in preeclampsia.