Extra- and intra-ovarian factors in polycystic ovary syndrome: impact on oocyte maturation and embryo developmental competence

Abstract

BACKGROUNDPolycystic ovary syndrome (PCOS) is a common metabolic dysfunction and heterogeneous endocrine disorder in women of reproductive age. Although patients with PCOS are typically characterized by increased numbers of oocytes retrieved during IVF, they are often of poor quality, leading to lower fertilization, cleavage and implantation rates, and a higher miscarriage rate.METHODSFor this review, we searched the database MEDLINE (1950 to January 2010) and Google for all full texts and/or abstract articles published in English with content related to oocyte maturation and embryo developmental competence.RESULTSThe search showed that alteration of many factors may directly or indirectly impair the competence of maturating oocytes through endocrine and local paracrine/autocrine actions, resulting in a lower pregnancy rate in patients with PCOS. The extra-ovarian factors identified included gonadotrophins, hyperandrogenemia and hyperinsulinemia, although intra-ovarian factors included members of the epidermal, fibroblast, insulin-like and neurotrophin families of growth factors, as well as the cytokines.CONCLUSIONSAny abnormality in the extra- and/or intra-ovarian factors may negatively affect the granulosa cell–oocyte interaction, oocyte maturation and potential embryonic developmental competence, contributing to unsuccessful outcomes for patients with PCOS who are undergoing assisted reproduction.

Cumulative live-birth rate in women with polycystic ovary syndrome or isolated polycystic ovaries undergoing in-vitro fertilisation treatment

“…It was suggested that this increased miscarriage rate in PCOS was not explained genetically by increased risk of embryonic aneuploidy [21]. As reviewed by Qiao and Feng [22], there is a multitude of endocrine and metabolic dysfunctions like LH hypersecretion, hyperandrogenaemia and hyperinsulinaemia, as well as altered intraovarian paracrine/autocrine factors, which are characteristic of PCOS and could be implicated in the impaired embryo developmental competence observed in PCOS.…”

Response of porcine oocytes exposed to testosterone and substance P in vitro

“…This may be due to the inhibition of the expression of some proteins required for oocyte growth, for example the differentiating growth factor (GDF-9). Other authors (9,27) have shown that in the case of women who suffer from PCOS resulting from hyperandrogenism, the expression of this protein is reduced.…”

“…Other authors have reported that there are abnormalities in the transcription of certain genes in oocytes obtained from women with PCOS (7,27). It has been shown that T has an effect on the expression of proteins from the family of transforming growth factor beta (TGF-β), for example there is a lower level of GDF-9 transcript in oocytes isolated from women with PCOS (27).…”

“…The first of them is the previously mentioned lack of GDF-9 caused by testosterone. This results in insufficient production of the matrix, due to which granulosa cells undergo expansion to a smaller extent (19,27).…”

“…Consequently, the impairment of a delicate balance within the microenvironment of the ovarian follicle, disrupting the activity of theca and granulosa cells, causes disturbances or suspension of oocyte growth and development. However, when ovulation occurs, the oocyte is of a very poor quality that leads to the reduced frequency of fertilization and subsequent implantation as well as increases the risk of miscarriage (27).…”