Endothelial nitric oxide synthase immunoreactivity in early gestation and in trophoblastic disease.
OBJECTIVE
To study the localisation of the endothelial nitric oxide synthase (eNOS) in the normal placenta, with special emphasis on the implantation site in the first trimester of pregnancy, and in the different subtypes of trophoblastic cells in gestational trophoblastic disease.


METHODS
The immunoperoxidase technique with an antibody directed against eNOS was applied to paraffin sections from first and second trimester placentas, placenta accreta, partial and complete hydatidiform moles, and choriocarcinoma. Immunoperoxidase staining for human placental lactogen (hPL) was performed on parallel sections.


RESULTS
Prominent immunoreactivity for eNOS was found to be present in the intermediate trophoblastic cells of the cell columns of the anchoring villi and in trophoblastic cells at the implantation site. Staining was also present in the syncytiotrophoblast, most conspicuous at the apical cell border. In trophoblastic disease, proliferating large mononuclear cells, which were strongly positive for hPL, were found to be immunoreactive for eNOS.


CONCLUSIONS
eNOS immunoreactivity is strongly positive in the extravillous trophoblastic cells and to a lesser extent in the syncytiotrophoblast. In the former it may play a role in implantation and vascular invasion. Cells with differentiation to intermediate trophoblast in complete hydatidiform mole and choriocarcinoma also show high levels of eNOS, which may be associated with the haematogenous mode of spread of trophoblastic disease.
Ariel
I
I
Hadassah University Hospital and the Hebrew University-Hadassah Medical School, Jerusalem, Israel. ariel@hadassah.org.il
Hochberg
A
A
Shochina
M
M
D002822:Choriocarcinoma / Q000201:enzymology; D005260:Female; D006801:Humans; D006828:Hydatidiform Mole / Q000201:enzymology; D007124:Immunoenzyme Techniques; D019001:Nitric Oxide Synthase / Q000032:analysis*; D052250:Nitric Oxide Synthase Type III; D010920:Placenta / Q000201:enzymology*; D010921:Placenta Accreta / Q000201:enzymology; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D014328:Trophoblastic Neoplasms / Q000201:enzymology*; D014327:Trophoblasts / Q000201:enzymology; D014594:Uterine Neoplasms / Q000201:enzymology*
C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III