Blastocyst collapse as an embryo marker of low implantation potential: a time-lapse multicentre study.

Spontaneous blastocyst collapse during in vitro embryo development has been suggested as a novel marker of embryo quality. Therefore, the aim of this multicentre study was to carry out a retrospective multicentre analysis to investigate the correlation between blastocyst collapse and pregnancy outcome. Here, 1297 intracytoplasmic sperm injection (ICSI)/in vitro fertilization (IVF) fresh cycles, with an elective single blastocyst transfer (eSET) were included in this study. Embryos were cultured individually in 6.0% CO2, 5.0% O2, 89.0% N2, using single step medium (GTLTM VitroLife, Sweden) or sequential medium (CookTM, Cook Medical, Australia) and selected for transfer using standard morphological criteria. With the use of time-lapse monitoring (TLM), blastocysts were analyzed by measuring the maximum volume reduction and defined as having collapsed, if there was ≥ 50% volume reduction from the expanded blastocyst and the collapse event. Following embryo replacement, each blastocyst was retrospectively allocated to one of two groups (collapsed or not collapsed). Here, 259 blastocysts collapsed once or more during development (19.9%) and the remaining 1038 either contracted minimally or not collapsed (80.1%). A significantly higher ongoing pregnancy rate (OPR) of 51.9% (95% CI 48.9-59.9%) was observed when blastocysts that had not collapsed were replaced compared with cycles in which collapsed blastocysts were transferred 37.5% (95% CI 31.6-43.4%). This study suggests that human blastocysts that collapse spontaneously during development are less likely to implant and generate a pregnancy compared with embryos that do not. Although this is a retrospective study, the results demonstrated the utility of collapse episodes as new marker of embryo selection following eSET at blastocyst stage.

Anti-mullerian hormone and cumulative pregnancy outcome in in-vitro fertilization.

PURPOSE: To evaluate the role of Anti-mullerian hormone (AMH) in predicting cumulative pregnancy outcome during in-vitro fertilization (IVF) treatment. METHODS: Serum AMH levels on day 6 of ovarian stimulation were taken from 180 women undergoing IVF with or without intracytoplasmic sperm injection (ICSI). The main outcome measures were ongoing pregnancy in the fresh cycle, cumulative ongoing pregnancy and ovarian response. RESULTS: There was a trend of higher median AMH levels in subjects achieving ongoing pregnancy in the fresh IVF cycle. The median AMH levels were significantly higher in subjects attaining ongoing pregnancy cumulatively and in subjects showing ovarian hyper-response in the stimulated cycle. Areas under the ROC curves were 0.606 and 0.792 for the prediction of cumulative ongoing pregnancy and ovarian hyper-response respectively. CONCLUSIONS: Serum AMH concentration on day 6 of stimulation was significantly higher in subjects who achieved cumulative ongoing pregnancy in IVF compared to those who did not. Serum AMH is a reasonably good predictor of ovarian hyper-response.

Activin A inhibits activation of human primordial follicles in vitro.

PURPOSE: To determine whether Activin A affects the activation and survival of human primordial follicles in vitro. METHODS: Ovarian cortical biopsies from eight women undergoing elective caesarean sections or benign gynaecological procedures were taken and cut into small pieces (1-3 mm(3)), cultured in serum-free medium for 7 days with/without human recombinant Activin A at a concentration of either 50 or 100 ng/ml. Ovarian tissue were analysed by histology for follicle viability, development and density. RESULT(S): Significant activation of primordial follicles within cultured cortical tissue was observed after 7 days in control medium. However, medium supplemented with Activin A at 50 ng/ml resulted in significant inhibition of follicular activation. Increasing the concentration of Activin A to 100 ng/ml reversed the inhibitory effect. The effect of Activin A appeared to be specific to activation of non-growing (primordial) follicles into the growing population since no significant differences in follicle viability was observed between treatment groups. CONCLUSION(S): Activin A at a concentration of 50 ng/ml can inhibit the spontaneous activation of human primordial follicles in vitro indicating that this may be a component of the signalling mechanisms that maintain follicular quiescence.

HCG up-regulates hypoxia inducible factor-1 alpha in luteinized granulosa cells: implications for the hormonal regulation of vascular endothelial growth factor A in the human corpus luteum.

Vascular endothelial growth factor (VEGF)-dependent angiogenesis is essential for normal luteal development. Although it is believed that hypoxia is the primary inducer of VEGF, in the corpus luteum it is up-regulated by human chorionic gonadotrophin (hCG). As hypoxia-inducible factor (HIF)1A has been shown to regulate VEGFA under ligand-stimulated conditions, we hypothesized that the effect of hCG on luteal VEGFA was mediated through HIF1A. We studied the effect of hCG on VEGFA and HIF1A expression in human luteinized granulosa cells in vitro and in human corpora lutea in vivo. HCG up-regulated VEGFA (P < 0.05) and HIF1A (P < 0.001) in vitro and VEGFA (P < 0.05) and HIF1A (P < 0.05) in vivo. There was a correlation between HIF1A and VEGFA in vivo (P < 0.005) and in vitro (P < 0.05). Nuclear HIF1A in granulosa-lutein cells was highest during luteal formation and absent from the fully functional corpus luteum (P < 0.05). Both VEGFA (P < 0.001) and HIF1A (P < 0.01) were up-regulated by dibutyryl-cAMP, through a PKA pathway. Hypoxia increased VEGFA (P < 0.001) and HIF1A (P < 0.05) expression and hCG further augmented VEGFA (P < 0.001) and HIF1A (P < 0.01) under hypoxic conditions. However, progesterone increased hCG-stimulated VEGFA but had no effect on HIF1A expression. The expression of HIF1A is therefore hormonally regulated in luteal cells in vitro and in vivo and may regulate VEGFA expression under normoxic and hypoxic conditions. However, the differential effects of progesterone suggest that not all regulation of VEGFA is associated with an up-regulation of HIF1A.

A two-step serum-free culture system supports development of human oocytes from primordial follicles in the presence of activin.

BACKGROUND: The objective of this study was to determine whether follicles grown within human ovarian cortical strip culture for 6 days in serum-free medium could be isolated at the secondary stage of pre-antral development and grown in vitro to the late pre-antral/early antral stage during a 4 day culture period. METHODS: Ovarian cortical biopsies were obtained from six women aged 26-40 years, with informed consent, during elective Caesarean section. Small tissue slices of ovarian cortex, with underlying stromal tissue removed, were cultured in serum-free medium for 6 days and at the end of this period pre-antral (secondary) follicles were dissected from the strips. Seventy-four intact pre-antral follicles ranging in size (66-132 microm) (mean size 100 microm +/- 3.4) were selected for further culture. Follicles were placed individually within V-shaped microwell culture plates in serum-free medium in the presence (n = 38) or absence (n = 36) of 100 ng/ml of human recombinant activin A. RESULTS: Pre-antral follicles grown for 4 days in the presence of activin A grew to a larger size (mean diameter 143 microm +/- 7.4) than those grown in control medium (mean diameter 111 microm +/- 8) (P < 0.005). Ninety percent of follicles cultured in the presence of activin A increased in size during the first 2 days of culture compared with only 36% of follicles in control medium (P > 0.005). Of the follicles surviving the entire culture period, 30% of those cultured in the presence of activin A showed normal morphology with intact oocytes and antral formation. None of the follicles grown in control medium developed antral cavities and >90% of those follicles collected at the end of the culture period showed signs of oocyte degeneration. CONCLUSIONS: The results reported here demonstrate that under certain conditions, it is possible to achieve accelerated oocyte/follicle development from human primordial/primary follicles. This provides the first encouraging step towards achieving full in vitro growth of human oocytes.

Role of luteal glucocorticoid metabolism during maternal recognition of pregnancy in women.

The human corpus luteum (hCL) is an active, transient, and dynamic endocrine gland. It will experience extensive tissue and vascular remodeling followed by 1) demise of the whole gland without any apparent scarring or 2) maintenance of structural and functional integrity dependent on conceptus-derived human chorionic gonadotropin (hCG). Because cortisol has well-characterized roles in tissue remodeling and repair, we hypothesized that it may have a role in controlling luteal dissolution during luteolysis and would be locally produced toward the end of the luteal cycle. Glucocorticoid-metabolizing enzymes [11beta-hydroxysteroid dehydrogenase (11betaHSD) types 1 and 2] and the glucocorticoid receptor (GR) were assessed in hCL and cultures of luteinized granulosa cells (LGC) using immunofluorescence and quantitative RT-PCR. Furthermore, the effect of cortisol on steroidogenic cell survival and fibroblast-like cell activity was explored in vitro. The hCL expressed 11betaHSD isoenzymes in LGC and nuclear GR in several cell types. hCG up-regulated the expression and activity of 11betaHSD type 1 (P < 0.05) and down-regulated type 2 enzyme (P < 0.05) in vitro and tended to do the same in vivo. Cortisol increased the survival of LGC treated with RU486 (P < 0.05) and suppressed the activity of a proteolytic enzyme associated with luteolysis in fibroblast-like cells (P < 0.05). Our results suggest that, rather than during luteolysis, it is luteal rescue with hCG that is associated with increased local cortisol generation by 11betaHSD type 1. Locally generated cortisol may therefore act on the hCL through GR to have a luteotropic role in the regulation of luteal tissue remodeling during maternal recognition of pregnancy.

Mid-luteal endometrial intracrinology following controlled ovarian hyperstimulation involving use of a gonadotrophin releasing hormone antagonist.

BACKGROUND: There are concerns of reduced pregnancy rates with the use of gonadotrophin-releasing hormone antagonists (GnRH antagonists) in IVF/ICSI cycles. Sex steroids and their metabolizing enzymes in the endometrium may play a vital role in embryo implantation. This study has evaluated the levels and localization of sex-steroid receptors and metabolizing enzymes, 3beta-hydroxysteroid dehydrogenases (3betaHSD) and selected 17beta-HSD (17betaHSD), in mid-luteal endometrium of women treated with GnRH antagonist (Cetrorelix) and recombinant FSH (rFSH; Gonal-F) with luteal phase progesterone supplementation. METHODS: Mid-luteal phase endometrial biopsies were obtained from oocyte donors undergoing ovarian stimulation and from control women with regular periods. Immunohistochemistry and real-time quantitative-polymerase chain reaction (QRT-PCR) were used to compare protein and mRNA expression of progesterone receptor (PR), estrogen receptor alpha (ERalpha), estrogen receptor beta (ERbeta), androgen receptor (AR), 3betaHSD1, 3betaHSD2, 17betaHSD2 and 17betaHSD5. RESULTS: Cetrorelix-rFSH treatment caused a mid-luteal suppression of PR protein expression in the endometrial stroma, surface epithelium and glands, although expression in the glands of control samples was variable. In contrast, the treatment caused an increase in PR staining in perivascular cells. No other significant differences in protein expression were observed between the two groups. mRNA levels of AR, ERalpha, 3betaHSD1 and 17betaHSD2 were significantly reduced in the treatment group. PR mRNA levels were also reduced by GnRH antagonist-rFSH treatment, but the difference was not significant. CONCLUSIONS: Changes in the expression of sex-steroid receptors and metabolizing enzymes may lead to alterations in the activity and intracellular availability of estrogens, progestogens and androgens in endometrium of women treated with Cetrorelix and rFSH. Their impact on embryo implantation merits further evaluation.

Prospective analysis of the relationships between the ovarian follicle cohort and basal FSH concentration, the inhibin response to exogenous FSH and ovarian follicle number at different stages of the normal menstrual cycle and after pituitary down-regulation.

BACKGROUND: Analyses of the follicular reserve and activity of the ovary are central to our understanding of the regulation of follicular development. We have carried out a prospective analysis of endocrine and biophysical assessments under three differing basal conditions: the early follicular and mid-luteal phases, and following GnRH analogue down-regulation. METHODS: Hormonal analyses were carried out before and after a single dose of FSH on spontaneously ovulating women (n = 58). Ovarian volume and antral follicle count (AFC) were also determined. RESULTS: Inhibin B and estradiol concentrations were increased by FSH under all three conditions, and inhibin A in the follicular phase and after down-regulation. Basal hormone concentrations, except inhibin A and B after down-regulation, did not generally correlate with AFC. A close relationship between inhibin B and AFC was evident at all stages after FSH administration (r = 0.70-0.77). AFC and inhibin B after FSH stimulation were well correlated with the number of oocytes recovered after superovulation. Multivariate analysis demonstrated that inhibin B after FSH administration in the down-regulated state showed the closest correlation with oocyte number. In the more clinically useful early follicular and luteal phases, basal FSH was the most significant contributor to the number of oocytes, with a significant contribution from luteal phase AFC. CONCLUSIONS: These data extend our understanding of the relationships between follicular number, follicular functional activity, and the recruitable follicular population. Down-regulation and subsequent FSH stimulation was required to clearly demonstrate the close relationship between inhibin B and the ovarian reserve. Without such complex manipulation, early follicular phase FSH (supplemented by AFC in the relatively hypogonadotrophic luteal phase) remains of greater value in predicting the ovarian reserve than the currently known direct products of the ovary.