The presence of histidine-rich glycoprotein in the female reproductive tract and in embryos.

A well-regulated angiogenesis is crucial for proper embryo implantation, embryogenesis, and pregnancy development. Monitoring the presence and distribution of angiogenic regulators in the female reproductive tract and in the early embryo is important for a broader understanding of the molecular aspects of fertility, embryogenesis, and pregnancy. Histidine-rich glycoprotein (HRG) is a glycoprotein involved in angiogenesis. Its presence in the female reproductive tract or in embryos has not previously been studied. Follicular fluid, culture medium, and embryos were obtained from patients undergoing in vitro fertilization (IVF). Biopsies from inner genitalia and placenta were collected at surgery. Histidine-rich glycoprotein presence was investigated by immunohistochemistry and Western blot. Polymerase chain reaction (PCR) was used to determine HRG expression in tissues or by embryos. We identified HRG in follicular fluid, the female reproductive tract, and placenta, as well as in the embryos. Moreover, HRG expression was observed in blastocysts. Thus, the angiogenic properties of HRG might affect fertility.