Transforming growth factor-beta 1 in the human endometrium.

Transforming growth factor-beta 1 (TGF-beta 1) is a polypeptide involved in a variety of important physiological and pathophysiological processes such as the implantation of the embryo into the endometrium. Many factors seem to be related to this event. TGF-beta 1 is involved in many mechanisms both in endometrial and in embryonic tissues: it induces proliferation and differentiation, it regulates proteolytic activity and it modulates the maternal immune response. This study evaluated the presence of TGF-beta 1 in the endometrium during normal menstrual cycles and in the uterine fluids during induction of ovulation in the framework of an in vitro fertilization program. Immunohistochemistry was used to identify TGF-beta 1 in the endometrium and immunodot-blot to quantitate TGF-beta 1 in the uterine cavity fluid. The study shows that TGF-beta 1 is present in the endometrial tissue and its secretion is modulated during the menstrual cycle, as demonstrated immunohistochemically; its production seems to be controlled by ovarian steroids. In conclusion, TGF-beta 1 influences the growth and differentiation of the embryo, as well as the activation of embryonic proteolytic enzymes, and it modulates the maternal-embryonic immune response. Its variability in the uterine cavity is demonstrated in this study, and the underexpression of TGF-beta 1 in the uterine cavity might be responsible for failed implantation.