Chagas disease affects the human placental barrier’s turnover dynamics during pregnancy

BACKGROUND

Trypanosoma cruzi crosses the placental barrier and produces the congenital transmission of Chagas disease (CD). Structural alterations of the chorionic villi by this parasite have been described in vitro, but little is known about trophoblast turnover in placentas from women with CD.

OBJECTIVE

To analyze the proliferation and fusion processes in placentas from women with CD.

METHODS

Archived human term placenta paraffin-embedded blocks were used, from women with CD (CDP), and no pathology (NP). Immunohistochemistry tests were performed for Ki67 to calculate the proliferation index (PI) of cytotrophoblast (CTB) and Syncytin-1, a fusion marker of syncytiotrophoblast (STB). Hematoxylin/Eosin stained sections were employed to analyze STB percentages, STB detachment areas and syncytial knots quantity. Non parametric Student’s t-tests were performed (p < 0.05).

RESULTS

Syncytial knots and STB detachment significantly increased in placental villi from the CDP group. STB percentage was significantly lower in the CDP group as well as the PI and Syncytin-1 expression significantly decreased in these placentas, compared with control (NP).

CONCLUSION

Dynamic of trophoblast turnover is altered in placentas from women with CD. These changes may lead into a gap in the placental barrier possibly allowing the parasite entry into the chorionic villi.

Key words:
congenital Chagas disease; Trypanosoma cruzi; trophoblast turnover; Ki67 antigen; Syncytin-1 antigen