PLACENTAL PROTEIN 13 (PP13) ADMINISTRATION TO PREGNANT RATS LOWERS BLOOD PRESSURE AND AUGMENTS FETAL GROWTH AND VENOUS REMODELING

Reduced first trimester concentrations of placental protein 13 (PP13), a placenta-specific galectin, are associated with subsequent development of preeclampsia, which is a major pregnancy disorder. We previously showed that PP13 has a vasodilatory effect on isolated pressurized uterine arteries, reduces blood pressure and augments expansive remodeling of the uteroplacental vasculature in pregnant rats. In this study, slow-release osmotic pumps were implanted on day 8 of rat pregnancy to provide one week of PP13 supplementation. Treatment was associated with blood pressure reduction that returned to normal at day 15, augmented venous expansion, and increased placental and pup weights. Administration of a truncated PP13 variant (delT221) that is unable to bind carbohydrates - a rare spontaneous mutation associated with a high frequency of severe early preeclampsia among blacks in South Africa - produced a hypotensive effect like the full length molecule , but failed to cause venous remodeling and to increase placental and pup weights. These results indicate the importance of PP13 binding to carbohydrates for inducing utero-placental vascular remodeling and improving reproductive outcome. Future studies are needed to determine whether beneficial effects would be evident in animal models of preeclampsia, or in women predisposed to the development of preeclampsia.