Histochemistry of placental alkaline phosphatase in preeclampsia

Abstract

Objectives: Placental alkaline phosphatase (PALP) is synthesized in placenta and increases with gestational age. Alkaline phosphatase supports pregnancy and could play an essential role in nutrient supply and growth of the fetus. Preeclampsia is a systemic disorder which affects 5 to 7 percent of women worldwide and is a major cause for maternal and neonatal morbidity and mortality. As it has a major role in fetal growth, nutrition and defense mechanism study of alkaline phosphatase enzymatic activity becomes essential. Methods: 50 normal and 50 preeclamptic placentae were collected immediately after delivery from Department of Obstetrics and Gynecology. Placentae were obtained from known preeclamptic consenting cases who had no history of hypertension before pregnancy or during first 20 weeks of gestation, who had consistently recorded systolic and diastolic blood pressure of 140 / 90 mm of Hg or above and proteinuria ≥ 300mg / 24 hrs. Alkaline phosphatase activity was demonstrated by using modified Gomori's method. Results: Intensity of PALP localization was stronger in preeclamptic placentae as compared to normotensive placentae. Conclusion: Placental ischemia is evident in preeclampsia. Uteroplacental insufficiency leads to increased syncytial damage in preeclamptic placentae which may lead to abnormally high PALP activity and consequent increase in serum alkaline phosphatase.