Endométrio na janela de implantação em mulheres com síndrome dos ovários policísticos

Abstract

The human endometrium undergoes to a complex series of proliferative and secretory changes in each menstrual cycle and displays only a short period of receptivity, known as the "window of implantation", necessary for the implantation of the blastocyst in the uterus. The implantation process occurs in a sequential manner, leading to the establishment of pregnancy. Morphofunctional changes during this period may prevent or hinder the implantation. For this reason, the study of the endometrium at this stage is important for the improvement of therapies that may interfere with the mechanisms involved in maternal-embryonic interaction. Several gynecological disorders, including polycystic ovary syndrome (PCOS), are associated with decreased fertility and uterine receptivity. In spite of recent advances in assisted reproduction techniques, allowing the selection of high quality embryos, the implantation rate remains low and has not increased enough in recent decades. This article aims at reviewing the endometrial aspects of the "window of implantation" in women with polycystic ovary syndrome, focusing mainly on adhesion molecules. For that purpose, we analyzed 105 articles published in journals indexed in PubMed in the last 50 years (up to May 2011). In conclusion, the endometrial receptivity seems to be the major limiting factor for the establishment of pregnancy in a large number of gynecological diseases, including PCOS, and treatment to improve implantation rates is likely to be taken towards this direction.

Impaired receptivity and decidualization in DHEA-induced PCOS mice

“…Although ovarian dysfunction is pharmacologically restored by ovulation induction agents8, PCOS patients still exhibit a higher rate of implantation failure and spontaneous miscarriage9. These studies suggest that the successful rate in PCOS patients remain low even if the excellent embryos are selected for transfer10. We also showed that blastocysts from normal mice are unable to implant in PCOS recipients (Fig.…”

“…Even after ovulation is pharmacologically restored, anovulatory patients have reduced cumulative pregnancy rates, and exhibit a higher rate of implantation failure and spontaneous miscarriage9. Even if the excellent embryos are selected for transfer, the successful rate in PCOS patients remain low10. PCOS is associated higher rates of early clinical pregnancy loss (30–50%)11.…”

Small leucine-rich proteoglycans (SLRPs) in the endometrium of polycystic ovary syndrome women: a pilot study

“…Growth factors mediating inflammation, including cytokines not only affect endometrial epithelial proliferation, but may alter factors in the extracellular matrix (ECM), including the production and action of small leucine-rich proteoglycans (SLRPs) [9, 10]. These proteoglycans play an important role in tissue homeostasis and cell proliferation, and protect the endometrium against agents that induce excessive endometrial proliferation [11–14].…”

“…The increased risk of endometrial hyperplasia and malignancy in PCOS is believed to be due not only to the reduction in the cyclic effect of progesterone, leading to chronic estrogen exposure, but also to the abnormal production of a large number of growth factors, cytokines, and other elements mediating inflammation [9, 10]. These factors may alter factors in the ECM, including SRLPs.…”

Apolipoprotein A1 as a novel anti-implantation biomarker in polycystic ovary syndrome: A case-control study

“…[ 1 4 5 ] Polycystic ovary syndrome as a complex disorder is associated with several health complications including obesity, hyperandrogenism, metabolic syndrome, hirsutism, acne, ovarian dysfunction, and infertility. [ 4 6 7 ] Although anovulation is an obvious cause of infertility in polycystic ovary syndrome, growing evidence suggests that endometrial receptivity also contributes to infertility of these patients. [ 1 7 8 ]…”