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Protein S deposition at placenta: a possible role of protein S other than anticoagulation

Makiko Matsumoto1, Daisuke Tachibana, Hiroyuki Nobeyama

  • 1Department of Obstetrics and Gynecology, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka, Japan. m-0508@med.osaka-cu.ac.jp

Blood Coagulation & Fibrinolysis : an International Journal in Haemostasis and Thrombosis
|October 4, 2008
PubMed

Protein S is an antithrombotic cofactor for protein C that also has multifunctional anti-inflammatory, cellular protective, apoptotic and mitogenic properties. Protein S levels are thought to decrease during pregnancy, but the underlying mechanism remains unknown. We compared protein S concentrations throughout normal pregnancy with those of nonpregnant women and measured plasma C4b-binding protein levels in nonpregnant women and in pregnant women at the 40th gestational week. We also examined protein S and C4b-binding protein in the placenta by immunohistochemical staining at early (20th gestational week) and late (40th gestational week) stages of pregnancy. Plasma protein S activity and free protein S-antigen levels significantly decreased from the 10th gestational week and total protein S antigen decreased from the 20th. C4b-binding protein levels between pregnant and nonpregnant women did not significantly differ. The stainable portion of protein S was located at the fetomaternal interface, particularly at degenerative villi. C4b-binding protein was weakly stained at the same areas as protein S. Neither protein S nor C4b-binding protein were stained at normal villi. These results indicated that protein S can protect or restore damaged villi via a physiological effect in addition to its anticoagulation properties.

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