Immunohistochemical localisation of transforming growth factor-beta in first and third trimester human placenta

Recently it has been demonstrated that human placental tissue is a source of transforming growth factor-beta (TGF-beta) and that it expresses high TGF-beta mRNA activity. For a better understanding of its in vivo function, it was necessary to determine the site of TGF-beta synthesis in placenta. We have demonstrated that TGF-beta immunoreactivity is present in the cytoplasm of syncytiotrophoblast cells in both early and term placenta. The most intense staining was, however, observed in the first trimester trophoblast syncytial sprouts known to be an early stage in the development of placental villi. These results suggest the involvement of TGF-beta in the paracrine regulation of trophoblast-endometrial interaction.