Placental alkaline phosphatase (PLAP) study in diabetic human placental villi infected with Trypanosoma cruzi.

Previous work has demonstrated that PLAP activity decreases in serum and placental villi from term chagasic and diabetic pregnant women. In vitro, T. cruzi induces changes in human syncytiotrophoblast's PLAP. Our aim was to determine if infection with T. cruzi induces changes in PLAP activity in diabetic and chagasic women's placenta, in order to elucidate if PLAP plays a role in the mechanisms of interaction between placenta and T. cruzi, and whether hyperglycemic conditions could worsen the placental infection. Using zymogrammes, Western blot, biochemical and immunohistological techniques, PLAP activity was determined in placental villi from diabetic and chagasic women, and in normal placentas cultured under hyperglycemic conditions with or without trypomastigotes. A significant reduction of PLAP expression was immunologically detected in infected diabetic and normal placental villi cultured under hyperglycemic conditions of 71 and 81%, respectively, compared with controls. A significant decrease of PLAP specific activity was registered in homogenates and in the culture media from both infected diabetic and normal placentas under hyperglycemic conditions (of about 50-70%), and in chagasic ones (of about 87%), when compared with controls. Thus, PLAP might be involved in parasite invasion and diabetic and hyperglycemic placentas could be more susceptible to T. cruzi infection.