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 hypertens ion, edema, and proteinuria, in which vasoconstriction, platelet aggre gation, and reduced uteroplacental blood flow contribute to preterm de livery, 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) rec eptors, PGI(2) synthase, cyclooxygenase-1 (COX-1), and COX-2 in placen tal and decidual tissue from preeclamptic and normal pregnancies. In s itu. hybridization and immunocytochemistry showed that primarily troph oblast layer and decidual cells express TXA(2) synthase, COX-1, and CO X-2 enzymes. Immunocytochemistry for PGI(2) synthase and in situ hybri dization for TXA(2) receptors showed similar results. Trophoblast laye r and decidua from preeclamptic pregnancies contained a greater abunda nce of mRNA and protein of TXA(2) synthase than the matched normal pre gnancies. In summary, our findings suggest that an increased local exp ression of TXA(2) synthase could be responsible for local and/or perip heral vascular changes in preeclampsia.