Intravillous eicosanoid compartmentalization and regulation of placental blood flow.
OBJECTIVE
To determine the roles of the eicosanoids thromboxane and prostacyclin, and their compartmentalization, in the regulation of placental blood flow.


METHODS
First, the sites of production of thromboxane and prostacyclin were determined within the placental villus using immunohistochemical staining for thromboxane and prostacyclin synthetase. Second, the production of both eicosanoids was studied in cultured trophoblasts and compared with that in the villous core by measuring the metabolites thromboxane B2 and 6-keto-prostaglandin F 1 alpha. Finally, eicosanoid production was assessed in intact villi after stimulation by an acute change in oxygen content, 5% to 95%.


RESULTS
Immunohistochemical staining showed that thromboxane production was primarily within the trophoblasts, whereas prostacyclin production was localized to the endothelial cells within the villi. In culture, we found preferential production of prostacyclin by the villous core cells and increased production of thromboxane by trophoblasts. Perifusion of intact villi demonstrated increased production of thromboxane by trophoblasts in response to an increase in oxygen content. Prostacyclin levels were too low to be detected.


CONCLUSIONS
Placental blood flow appears to be regulated by compartmentalized eicosanoids, with thromboxane affecting primarily the maternal side of the placental circulation and prostacyclin affecting primarily the fetal side.
Shellhaas
C S
CS
Department of Obstetrics and Gynecology, Duke University Medical Center, Durham, North Carolina, USA.
Coffman
T
T
Dargie
P J
PJ
Killam
A P
AP
Kay
H H
HH
D015121:6-Ketoprostaglandin F1 alpha / Q000096:biosynthesis* / Q000502:physiology; D002478:Cells, Cultured; D002824:Chorionic Villi / Q000201:enzymology / Q000378:metabolism*; D003577:Cytochrome P-450 Enzyme System / Q000032:analysis / Q000276:immunology; D015777:Eicosanoids / Q000096:biosynthesis / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D019746:Intramolecular Oxidoreductases; D007535:Isomerases / Q000032:analysis / Q000276:immunology; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008431:Maternal-Fetal Exchange / Q000502:physiology; D010100:Oxygen / Q000378:metabolism; D010920:Placenta / Q000098:blood supply* / Q000166:cytology / Q000201:enzymology / Q000648:ultrastructure; D011247:Pregnancy; D013929:Thromboxane B2 / Q000096:biosynthesis* / Q000502:physiology; D013930:Thromboxane-A Synthase / Q000032:analysis / Q000276:immunology; D013997:Time Factors; D014327:Trophoblasts / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*
D015777:Eicosanoids; D013929:Thromboxane B2; D015121:6-Ketoprostaglandin F1 alpha; D003577:Cytochrome P-450 Enzyme System; D007770:L-Lactate Dehydrogenase; D007535:Isomerases; D019746:Intramolecular Oxidoreductases; C022461:prostacyclin synthetase; D013930:Thromboxane-A Synthase; D010100:Oxygen