Reduced l-arginine Level and Decreased Placental eNOS Activity in Preeclampsia

• Published in: Placenta (Eastbourne) Vol. 27; no. 4; pp. 438 - 444
• Main Authors: Kim, Y.J., Park, H.S., Lee, H.Y., Ha, E.H., Suh, S.H., Oh, S.K., Yoo, H.-S.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-04-2006; Elsevier
• Subjects: ADMA; Adult; Arginine - analogs & derivatives; Arginine - blood; Arginine - metabolism; Biological and medical sciences; Blotting, Western; Case-Control Studies; Embryology: invertebrates and vertebrates. Teratology; Female; Fundamental and applied biological sciences. Psychology; Glu298Asp eNOS gene polymorphism; Humans; Immunohistochemistry; l-Arginine; Nitric oxide; Nitric Oxide Synthase Type III - genetics; Nitric Oxide Synthase Type III - metabolism; Placenta - metabolism; Placental eNOS activity; Polymorphism, Genetic; Pre-Eclampsia - genetics; Pre-Eclampsia - metabolism; Preeclampsia; Pregnancy; Retrospective Studies; Placental eNOS activity; ADMA; l-Arginine; Glu298Asp eNOS gene polymorphism; Nitric oxide; Preeclampsia; Vertebrata; Mammalia; Placenta; Pregnancy disorders; Arginine; Fetal membrane; Aminoacid; Pregnancy toxemia
• ISSN: 0143-4004; 1532-3102
• DOI: 10.1016/j.placenta.2005.04.011

Nitric oxide is produced enzymatically by the nitric oxide synthase (NOS), which converts
l-arginine in the presence of oxygen to
l-citrulline and NO. Moreover, it has been reported that asymmetric dimethylarginine (ADMA) acts as is an endogenous inhibitor of endothelial NOS (eNOS) by competing with the enzyme for
l-arginine.
In this study, we measured
l-arginine and ADMA in normal and preeclamptic women, and also investigated the association between the Glu298Asp
eNOS gene polymorphism and preeclampsia. Finally, we assessed eNOS expression levels in the placentas of both normal and preeclamptic patients, using Western blot and immunohistochemistry.
l-arginine levels were found to be significantly lower in the preeclamptic women than in the normal pregnant women (
p
=
0.02) but there were no significant differences in ADMA levels between the normal and preeclamptic women. We also determined there to be no association between the Glu298Asp
eNOS gene and preeclampsia. With regard to placental eNOS expression, we detected a lower degree of eNOS expression in the preeclamptic syncytiotrophoblasts than in the normal syncytiotrophoblasts. We suggest that reduced
l-arginine levels, rather than increased ADMA levels, contribute to the development of preeclampsia, and also that decreased placental eNOS expression constitutes a characteristic finding in preeclamptic placentas.