Histochemical analysis of placental phosphatases in cases of preterm preeclampsia

ABSTRACT

Disruption of normal placental morphology and function might correlate with several pregnancy disorders as preeclampsia and preterm labor. Many studies tried to localize placental alkaline phosphatase, and placental acid phosphatase in placentas of mothers with complicated pregnancy and try to find out whether the changes in their pattern have a direct bearing on functional and morphological integrity of the placental tissue and on the fetal growth and development. This study aims to find the difference in localization or intensity of placental alkaline phosphatase, and placental acid phosphatase in a group of preterm preeclarnpsia and in placentae of normotensive preterm ones, compared with normotensive term mothers. This study examined placentae obtained from 61 singleton pregnant women and it was performed over a period of three months started form 1[st] April 2008 till 30 [th] June 2008 and conducted at Al-Batool Maternity Teaching hospital in Mosul city in northern Iraq. Smokers, Rh negative mothers, and cases of diabetes mellitus were excluded. The study sample was divided into 3 groups after recording of medical reports of the history and clinical examination and accurate assignment of gestational age. Group 1 This group consisted of 25 normotensive women who delivered at term [between 38 and 42 weeks' gestation]. Group2 This group consisted of 23 normotensive women who delivered before 37 weeks' gestation spontaneously. Group3 This group consisted of 13 women with positive history of blood pressure equal to 140/90 mm Hg after 20 weeks of gestation and proteinuria 300 mg/ 24 hrs or [3]1+ dipstick and delivered before 37 weeks' gestation. All placental sections of the three study groups were stained using alkaline phosphatase stain [Gomori's method-cobalt] and acid phosphatase stain [Gomori's method-lead] and submitted for light microscopic examination in Laboratory of Postgraduate Studies at the Department of Anatomy, Histology and Embryology in Mosul College of Medicine. This study revealed that most sections obtained from normotensive term group showed discrete localization of acid phosphatase P-ACP in all cellular elements of the placenta. Placental sections obtained from cases of preterm preeclampsia [group 3] and those obtained from spontaneous preterm labor [group 2] showed more intense acid phosphatase activity which was arranged in focal distribution. On the other hand, most sections obtained from normotensive term group revealed that alkaline phosphatase P-ALP was localized mostly in the syncytiotrophoblast, moderate reaction of the maternal deciduas, while villous stroma showed weak activity. Sections obtained from placentas of group 2 and group 3 women showed that very strong alkaline phosphatase activity expressed in syncytiotrophoblast, moderate to intense alkaline phosphatase activity in villous stroma and maternal deciduas. The present study demonstrated that the placental tissue in cases of preterm preeclampsia and in cases of spontaneous prematurity exhibits changes in the activity patterns