The impact of ovarian stimulation for IVF on the developing embryo

Maternal HLA-C2 and 14 bp insertion in HLA-G is associated with recurrent implantation failure after in vitro fertilization treatment

The major rate-limiting step in in vitro fertilization (IVF) success appears to be the implantation of the semi-allogeneic embryo into the maternal endometrium. To determine possible risk factors of recurrent failure of embryos to implant, we investigated immunogenetic determinants as level of human leukocyte antigen (HLA) histocompatibility, frequency of killer-cell immunoglobulin-like receptors (KIR) and HLA-C alleles and HLA-G polymorphism. We DNA typed women with recurrent implantation failure (RIF) and their partners for classical HLA Class I, HLA Class II, HLA-G and KIR alleles and compared these results with couples with successful embryo implantation after their first IVF and normal fertile couples. No association was found between RIF and the degree of histocompatibility between partners or sharing of a specific antigen. Also, no significant difference in KIR haplotype or combination of HLA-C group and KIR was observed. We did find a higher frequency of HLA-C2 and a higher frequency of 14 base pair (bp) insertion in HLA-G in women with RIF. Therefore we conclude that the degree of histocompatibility between partners is not a determining factor for the occurrence of RIF. However, presence of the HLA-C2 allotype and the HLA-G allele with a 14 bp insertion is a significant risk factor.

Altered glucose metabolism in mouse and humans conceived by IVF

In vitro fertilization (IVF) may influence the metabolic health of children. However, in humans, it is difficult to separate out the relative contributions of genetics, environment, or the process of IVF, which includes ovarian stimulation (OS) and embryo culture. Therefore, we examined glucose metabolism in young adult humans and in adult male C57BL/6J mice conceived by IVF versus natural birth under energy-balanced and high-fat-overfeeding conditions. In humans, peripheral insulin sensitivity, as assessed by hyperinsulinemic-euglycemic clamp (80 mU/m(2)/min), was lower in IVF patients (n = 14) versus control subjects (n = 20) after 3 days of an energy-balanced diet (30% fat). In response to 3 days of overfeeding (+1,250 kcal/day, 45% fat), there was a greater increase in systolic blood pressure in IVF versus controls (P = 0.02). Mice conceived after either OS alone or IVF weighed significantly less at birth versus controls (P < 0.01). However, only mice conceived by IVF displayed increased fasting glucose levels, impaired glucose tolerance, and reduced insulin-stimulated Akt phosphorylation in the liver after 8 weeks of consuming either a chow or high-fat diet (60% fat). Thus, OS impaired fetal growth in the mouse, but only embryo culture resulted in changes in glucose metabolism that may increase the risk of the development of metabolic diseases later in life, in both mice and humans.

The phenotype of an IVF child is associated with peri-conception measures of follicular characteristics and embryo quality

STUDY QUESTION

Are childhood measures of phenotype associated with peri-conception parental, IVF treatment and/or embryonic characteristics of IVF children?

SUMMARY ANSWER

Birthweight, childhood body mass index (BMI) and height of pre-pubertal IVF children were strongly associated with peri-conception factors, including follicular and embryonic characteristics.

WHAT IS KNOWN ALREADY

A growing number of studies have identified a range of phenotypic differences between IVF and naturally conceived pre-pubertal children; for example, birthweights are lower following a fresh compared with a thawed embryo transfer.

STUDY DESIGN, SIZE, DURATION

This retrospective cohort study included IVF children (n = 96) born at term (>37 weeks) after a singleton pregnancy from the transfer of either fresh or thawed embryos in New Zealand. Between March 2004 and November 2008, these children were subjected to clinical assessment before puberty.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Clinical assessment provided anthropometric measures of children aged 3.5-11 years old. Peri-conception factors (n = 36) derived retrospectively from parental, treatment, laboratory and embryonic variables (n = 69) were analysed using multiple stepwise regression with respect to standard deviation scores (SDSs) of the birthweight, mid-parental corrected BMI and height of the IVF children. Data from children conceived from fresh (n = 60) or thawed (n = 36) embryos, that met inclusion criteria and had high-quality data with >90% completeness, were analysed.

MAIN RESULTS AND THE ROLE OF CHANCE

Embryo treatment at transfer was identified as a predictor of birthweight with thawed embryos resulting in heavier birthweights than fresh embryos [P = 0.02, 95% confidence interval (CI) fresh minus thawed: -1.047 to -0.006]. Birthweight SDS was positively associated with mid-parental corrected BMI SDS (P = 0.003, slope 0.339 ± 0.100). Four factors were related (P < 0.05) to mid-parental corrected height SDS. In particular, child height was inversely associated with the diameter of lead follicles at oocyte retrieval (P < 0.0001, slope -0.144 ± 0.040) and with the quality score of embryos at transfer (P = 0.0008, slope -0.425 ± 0.157), and directly associated with the number of follicles retrieved (P = 0.05, slope 1.011 ± 0.497). Child height was also positively associated with the transfer of a fresh as opposed to thawed embryo (P < 0.001, 95% CI 0.275-0.750).

LIMITATIONS, REASONS FOR CAUTION

More than one embryo was transferred in most cycles so mean development and quality data were used. The large number of variables measured was on a relatively small sample size. Large cohorts from multiple clinics using a variety of treatment protocols and embryology methods are needed to confirm the associations identified and ultimately to test these factors as possible predictors of phenotype.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first study to directly associate peri-conception measures of IVF treatment with a pre-pubertal child's phenotype. Demonstration that peri-conception measures relate to a pre-pubertal child's phenotype extends the range of factors that may influence growth and development. These findings, if corroborated by larger studies, would provide invaluable information for practitioners, who may want to consider the impact of ovarian stimulation protocols as well as the quality of the embryo transferred on a child's growth and development, in addition to their impact on pregnancy rate.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by grants from the National Research Centre of Growth and Development New Zealand (grant 3682065) and the Australasian Paediatric Endocrine Group (APEG; grant 3621994), as well as a fellowship from Fertility Associates New Zealand awarded to M.P.G. In terms of competing interest, J.C.P is a shareholder of Fertility Associates. M.P.G. currently holds the position of Merck Serono Lecturer in Reproductive Biology. W.S.C. and P.L.H. have also received grants and non-financial support from Novo Nordisk, as well as personal fees from Pfizer that are unrelated to the current study. The other authors have no conflict of interest to declare.

Why we should transfer frozen instead of fresh embryos: the translational rationale

Epidemiologic studies have shown an increased rate of adverse perinatal outcomes, including small for gestational age (SGA) births, in fresh in vitro fertilization (IVF) cycles compared with frozen embryo transfer cycles. This increase is not seen in the donor oocyte population, suggesting that it is the peri-implantation environment created after superovulation that is responsible for these changes. During a fresh IVF cycle, multiple corpora lutea secrete high levels of hormones and other factors that can affect the endometrium and the implanting embryo. In this review, we discuss both animal and human data demonstrating that superovulation has significant effects on the endometrium and embryo. Additionally, potential mechanisms for the adverse effects of gonadotropin stimulation on implantation and placental development are proposed. We think that these data, along with the growing body of epidemiologic evidence, support the proposal that frozen embryo transfer should be considered preferentially, particularly in high responders, as a means to potentially decrease at least some of the adverse perinatal outcomes associated with IVF.

High maternal serum estradiol environment in the first trimester is associated with the increased risk of small-for-gestational-age birth

CONTEXT

There are increasing concerns that a disrupted endocrine environment may disturb the growth of the fetus. Assisted reproductive technology (ART) situates gamete/embryo in a supraphysiological estradiol (E2) environment and, thus, provides an ideal model to investigate this problem.

OBJECTIVE

Our objective was to investigate whether the maternal high-E2 environment in the first trimester increases the risks of low birth weight (LBW) and small-for-gestational-age (SGA) birth.

METHODS

In total, 8869 singletons born after fresh embryo transfer (ET) (n = 2610), frozen ET (n = 1039), and natural conception (NC) (n = 5220) and their mothers were included. Birth weight, LBW, SGA, and maternal serum E2 levels were investigated.

RESULTS

The mean serum E2 levels of women undergoing fresh ET at 4 and 8 weeks of gestation were significantly higher than those of the women undergoing frozen ET and the women with NC (P < .01). Serum E2 levels of women undergoing fresh ET at 4 and 8 weeks of gestation were positively correlated to those on the day of human chorionic gonadotropin (hCG) administration (r = 0.5 and r = 0.4, respectively; P < 0.01). The birth weight after fresh ET was significantly lower than that after frozen ET and NC (P < 0.01), with increased incidence of LBW and SGA (P < .05). Furthermore, in the fresh ET group, singletons of mothers with high E2 levels (≥10460 pmol/L on the day of hCG administration) had higher risks of LBW (P < .01) and SGA (P < .01) than those with low E2 levels, and maternal serum E2 level on the day of hCG administration negatively correlated with the birth weight (P < .01).

CONCLUSIONS

The maternal high-E2 environment in the first trimester is correlated with increased risks of LBW and SGA. Evaluation of serum E2 before ET should be adopted to reduce the possibility of high E2 exposure to gamete/embryo.

Single cell genomics: advances and future perspectives

Advances in whole-genome and whole-transcriptome amplification have permitted the sequencing of the minute amounts of DNA and RNA present in a single cell, offering a window into the extent and nature of genomic and transcriptomic heterogeneity which occurs in both normal development and disease. Single-cell approaches stand poised to revolutionise our capacity to understand the scale of genomic, epigenomic, and transcriptomic diversity that occurs during the lifetime of an individual organism. Here, we review the major technological and biological breakthroughs achieved, describe the remaining challenges to overcome, and provide a glimpse into the promise of recent and future developments.

Chromosomes in the porcine first polar body possess competence of second meiotic division within enucleated MII stage oocytes

To determine whether chromosomes in the porcine first polar body (PB1) can complete the second meiotic division and subsequently undergo normal pre-implantation embryonic development, we examined the developmental competence of PB1 chromosomes injected into enucleated MII stage oocytes by nuclear transfer method (chromosome replacement group, CR group). After parthenogenetic activation (PA) or in vitro fertilization (IVF), the cleavage rate of reconstructed oocytes in the IVF group (CR-IVF group, 36.4 ± 3.2%) and PA group (CR-PA group, 50.8 ± 4.2%) were significantly lower than that of control groups in which normal MII oocytes were subjected to IVF (MII-IVF group, 75.8 ± 1.5%) and PA (MII-PA group, 86.9 ± 3.7%). Unfertilized rates was significantly higher in the CR-IVF group (48.6 ± 3.3%) than in the MII-IVF group (13.1 ± 3.4%). The blastocyst formation rate was 8.3 ± 1.9% in the CR-PA group, whereas no blastocyst formation was observed in the CR-IVF group. To produce tetraploid parthenogenetic embryos, intact MII stage oocytes injected with PB1 chromosomes were electrically stimulated, treated with 7.5 μg/mL cytochalasin B for 3 h (MII oocyte + PB1 + CB group), and then cultured without cytochalasin B. The average cleavage rate of reconstructed oocytes was 72.5% (48 of 66), and the blastocyst formation rate was 18.7% (9 of 48). Chromosome analysis showed similar proportions of haploid and diploid cells in the control (normal MII oocytes) and CR groups after PA; overall, 23.6% of blastocysts were tetraploid in the MII oocyte + PB1 + CB group. These results demonstrate that chromosomes in PB1 can participate in normal pre-implantation embryonic development when injected into enucleated MII stage oocytes, and that tetraploid PA blastocysts are produced (although at a low proportion) when PB1 chromosomes are injected into intact MII stage oocytes.

Mice generated by in vitro fertilization exhibit vascular dysfunction and shortened life span

Children conceived by assisted reproductive technologies (ART) display a level of vascular dysfunction similar to that seen in children of mothers with preeclamspia. The long-term consequences of ART-associated vascular disorders are unknown and difficult to investigate in healthy children. Here, we found that vasculature from mice generated by ART display endothelial dysfunction and increased stiffness, which translated into arterial hypertension in vivo. Progeny of male ART mice also exhibited vascular dysfunction, suggesting underlying epigenetic modifications. ART mice had altered methylation at the promoter of the gene encoding eNOS in the aorta, which correlated with decreased vascular eNOS expression and NO synthesis. Administration of a deacetylase inhibitor to ART mice normalized vascular gene methylation and function and resulted in progeny without vascular dysfunction. The induction of ART-associated vascular and epigenetic alterations appeared to be related to the embryo environment; these alterations were possibly facilitated by the hormonally stimulated ovulation accompanying ART. Finally, ART mice challenged with a high-fat diet had roughly a 25% shorter life span compared with control animals. This study highlights the potential of ART to induce vascular dysfunction and shorten life span and suggests that epigenetic alterations contribute to these problems.

Abnormal DLK1/MEG3 imprinting correlates with decreased HERV-K methylation after assisted reproduction and preimplantation genetic diagnosis

Retrotransposons participate in cellular responses elicited by stress, and DNA methylation plays an important role in retrotransposon silencing and genomic imprinting during mammalian development. Assisted reproduction technologies (ARTs) may be associated with increased stress and risk of epigenetic changes in the conceptus. There are similarities in the nature and regulation of LTR retrotransposons and imprinted genes. Here, we investigated whether the methylation status of Human Endogenous Retroviruses (HERV)-K LTR retrotransposons and the imprinting signatures of the DLK1/MEG3. p57(KIP2) and IGF2/H19 gene loci are linked during early human embryogenesis by examining trophoblast samples from ART pregnancies and preimplantation genetic diagnosis (PGD) cases and matched naturally conceived controls. Methylation analysis revealed that HERV-Ks were totally methylated in the majority of controls while, in contrast, an altered pattern was detected in ART-PGD samples that were characterized by a hemi-methylated status. Importantly, DLK1/MEG3 demonstrated disturbed methylation in ART-PGD samples compared to controls and this was associated with altered HERV-K methylation. No differences were detected in p57(KIP2) and IGF2/H19 methylation patterns between ART-PGD and naturally conceived controls. Using bioinformatics, we found that while the genome surrounding the p57(KIP2) and IGF2/H19 genes differentially methylated regions had low coverage in transposable element (TE) sequences, the respective one of DLK1/MEG3 was characterized by an almost 2-fold higher coverage. Moreover, our analyses revealed the presence of KAP1-binding sites residing within retrotransposon sequences only in the DLK1/MEG3 locus. Our results demonstrate that altered HERV-K methylation in the ART-PGD conceptuses is correlated with abnormal imprinting of the DLK1/MEG3 locus and suggest that TEs may be affecting the establishment of genomic imprinting under stress conditions.

Mild ovarian stimulation for in vitro fertilization: one perspective from the USA

PURPOSE

To provide a perspective regarding mild ovarian stimulation, taking into account particular issues relevant in the United States

METHODS

Literature review and editorial commentary

RESULTS

Mild ovarian stimulation for IVF has some proven and some theoretical advantages over conventional stimulation, such as lower risk of ovarian hyperstimulation syndrome and lower cost per fresh IVF cycle. However, cumulative live birth rate, including transfers from fresh and frozen embryos, is likely to be lower with mild stimulation. The cost-effectiveness of mild stimulation IVF in the United States has not been established.

CONCLUSIONS

Mild ovarian stimulation is an appropriate option to consider for certain patient groups or based on patient preference. However, significant potential disadvantages limit its widespread acceptability for patients in the United States at this time.

Human embryonic stem cells derived by somatic cell nuclear transfer

Reprogramming somatic cells into pluripotent embryonic stem cells (ESCs) by somatic cell nuclear transfer (SCNT) has been envisioned as an approach for generating patient-matched nuclear transfer (NT)-ESCs for studies of disease mechanisms and for developing specific therapies. Past attempts to produce human NT-ESCs have failed secondary to early embryonic arrest of SCNT embryos. Here, we identified premature exit from meiosis in human oocytes and suboptimal activation as key factors that are responsible for these outcomes. Optimized SCNT approaches designed to circumvent these limitations allowed derivation of human NT-ESCs. When applied to premium quality human oocytes, NT-ESC lines were derived from as few as two oocytes. NT-ESCs displayed normal diploid karyotypes and inherited their nuclear genome exclusively from parental somatic cells. Gene expression and differentiation profiles in human NT-ESCs were similar to embryo-derived ESCs, suggesting efficient reprogramming of somatic cells to a pluripotent state.

ART and health: clinical outcomes and insights on molecular mechanisms from rodent studies

Since the birth of the first IVF-conceived child in 1978, the use of assisted reproductive technologies (ART) has grown dramatically, contributing to the successful birth of 5 million individuals worldwide. However, there are several reported associations of ART with pregnancy complications, such as low birthweight (LBW), preterm birth, birth defects, epigenetic disorders, cancer and poor metabolic health. Whether this is attributed to ART procedures or to the subset of the population seeking ART remains a controversy, but the most relevant question today concerns the potential long-term implications of assisted conception. Recent evidence has emerged suggesting that ART-conceived children have distinct metabolic profiles that may predispose to cardiovascular pathologies in adulthood. Because the eldest IVF individuals are still too young to exhibit components of chronic middle-aged syndromes, the use of animal models has become particularly useful in describing the effects of unusual or stressful preimplantation experiences on adult fitness. Elucidating the molecular mechanisms by which embryos integrate environmental signals into development and metabolic gene expression programs will be essential for optimizing ART procedures such as in vitro culture conditions, embryo selection and transfer. In the future, additional animal studies to identify mechanisms underlying unfavorable ART outcomes, as well as more epidemiological reviews to monitor the long-term health of ART children are required, given that ART procedures have become routine medical practice.

Phenotypic differences in children conceived from fresh and thawed embryos in in vitro fertilization compared with naturally conceived children

OBJECTIVE

To determine whether anthropometric and biochemical features differ in in vitro fertilization (IVF) children conceived via fresh (IVFF) or thawed (IVFT) embryo transfer compared with naturally conceived controls.

DESIGN

A cross-sectional controlled study.

SETTING

University clinical research unit.

PATIENT(S)

Healthy prepubertal children (3.5-11.0 years), singletons, born at term (>37 weeks), who were either naturally conceived (controls; n = 94) or IVF children conceived via the transfer of a fresh (IVFF; n = 72) or thawed (IVFT; n = 43) embryo.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Assessments of anthropometry (adjusted for parental variables), dual-energy X-ray absorptiometry-derived body composition, fasting plasma growth factors, lipids, and parameters of glucose regulation.

RESULT(S)

The IVFF but not the IVFT children weighed less at birth than the control children. The IVFF children were taller than both the controls and IVFT children. Sex-specific analyses showed height differences among girls, with IVFF girls being taller than their control and IVFT counterparts. Taller stature in IVFF children was associated with increased insulin-like growth factor I (IGF-I) concentrations compared with controls, whereas the IVFT children displayed increased IGF-II and decreased insulin-like growth factor binding protein 3 (IGFBP-3) concentrations compared with the controls. More favorable lipid profiles were also evident in IVFF but not IVFT children compared with the control children.

CONCLUSION(S)

These preliminary findings highlight that the transfer of a fresh versus a thawed IVF embryo affects height, plasma growth factor, and lipid profiles in childhood. Therefore, embryo derivation should be considered when assessing physical and biochemical phenotype of IVF children.

Antimüllerian hormone levels are strongly associated with live-birth rates after assisted reproduction

CONTEXT

Previous studies have suggested that antimüllerian hormone (AMH) levels are positively associated with in vitro fertilization (IVF) outcome through their relationship with oocyte yield and not by reflecting oocyte or embryo quality.

OBJECTIVE

The aim was to investigate whether AMH levels are associated with pregnancy and live-birth rates and whether the results may also reflect qualitative aspects of oocytes and embryos.

DESIGN

The study was a prospective cohort study between April 2008 and June 2011.

SETTING

The study was done at a university-affiliated private infertility center.

PATIENTS

The study cohort consisted of 892 consecutive women undergoing 1230 IVF-intracytoplasmic sperm injection cycles.

INTERVENTION(S)

AMH levels, analyzed using the DSL ELISA kit, were statistically adjusted for repeated treatments and age and analyzed for associations with treatment outcome.

MAIN OUTCOME MEASURES

Pregnancy rates, live-birth rates, and stimulation outcome parameters were measured.

RESULTS

AMH was log-normally distributed with a mean (SD) of 2.3 (2.5) ng/mL. Live-birth rates per started cycle (mean [95% confidence interval]) increased log-linearly from 10.7% [7.2-14.1] for AMH < 0.84 ng/mL (25th percentile) to 30.8% [25.7-36.0] for AMH > 2.94 ng/mL (75th percentile), Ptrend < .0001, being superior in women with polycystic ovaries. These findings were significant also after adjustments were made for age and oocyte yield. AMH was also associated with ovarian response variables and embryo scores.

CONCLUSIONS

AMH is strongly associated with live-birth rates after IVF-intracytoplasmic sperm injection. AMH may therefore serve as a prognostic factor for the chance of a pregnancy and live birth. Treatment outcome was superior in patients with polycystic ovaries. The findings also indicate that AMH may partially comprise information about oocyte quality.

Assessing the risks of genotoxicity in the therapeutic development of induced pluripotent stem cells

Induced pluripotent stem cells (iPSCs) have great potential for regenerative medicine as well as for basic and translational research. However, following the initial excitement over the enormous prospects of this technology, several reports uncovered serious concerns regarding its safety for clinical applications and reproducibility for laboratory applications such as disease modeling or drug screening. In particular, the genomic integrity of iPSCs is the focus of extensive research. Epigenetic remodeling, aberrant expression of reprogramming factors, clonal selection, and prolonged in vitro culture are potential pathways for acquiring genomic alterations. In this review, we will critically discuss current reprogramming technologies particularly in the context of genotoxicity, and the consequences of these alternations for the potential applications of reprogrammed cells. In addition, current strategies of genetic modification of iPSCs, as well as applicable suicide strategies to control the risk of iPSC-based therapies will be introduced.

Follicular fluid hormonal profile and cumulus cell gene expression in controlled ovarian hyperstimulation with recombinant FSH: effects of recombinant LH administration

PURPOSE

Down-regulation with gonadodropin-releasing agonist (GnRH-a) protocol during IVF stimulation leads to a severe endogenous LH suppression, which may affect the follicular development. The aim of the study was to evaluate the effects of recombinant LH (r-LH) administration, during late follicular development stages, in recombinant FSH (r-FSH) stimulated cycles on follicular fluid (FF) parameters and on cumulus cell quality.

METHODS

Twenty patients undergoing IVF were stimulated in a long GnRH agonist protocol with r-FSH alone or with r-LH supplementation when the leading follicle reached diameter of 14 mm. FF was collected at the time of oocyte retrieval from 32 follicles ≥ 18 mm. Serum FSH, LH, estradiol (E(2)), and progesterone (P(4)) were evaluated on the day of hCG administration. Intra-follicular E(2), P(4), AMH and TGF-β were assayed. Total RNA from 18 individual cumuli was isolated for gene expression analyses.

RESULTS

R-LH increased FF P(4) levels. FF TGF-β levels and PTGS2 and HAS2 expression in cumulus cells (CCs) positively correlated with increased P(4) levels observed in FFs, while a negative correlation was found between P(4) and AMH levels.

CONCLUSIONS

FF positive correlation between P(4) and TGF-β levels and CC expression of PTGS2 and HAS2 suggest an association with a better follicle quality. In addition, our data suggest that late follicular phase r-LH supplementation leads to a more advanced stage of follicular maturation.

Fresh embryo transfer versus frozen embryo transfer in in vitro fertilization cycles: a systematic review and meta-analysis

OBJECTIVE

To examine the available evidence to assess if cryopreservation of all embryos and subsequent frozen embryo transfer (FET) results in better outcomes compared with fresh transfer.

DESIGN

Systematic review and meta-analysis.

SETTING

Centers for reproductive care.

PATIENT(S)

Infertility patient(s).

INTERVENTION(S)

An exhaustive electronic literature search in MEDLINE, EMBASE, and the Cochrane Library was performed through December 2011. We included randomized clinical trials comparing outcomes of IVF cycles between fresh and frozen embryo transfers.

MAIN OUTCOME MEASURE(S)

The outcomes of interest were ongoing pregnancy rate, clinical pregnancy rate, and miscarriage.

RESULT(S)

We included three trials accounting for 633 cycles in women aged 27-33 years. Data analysis showed that FET resulted in significantly higher ongoing pregnancy rates and clinical pregnancy rates.

CONCLUSION(S)

Our results suggest that there is evidence that IVF outcomes may be improved by performing FET compared with fresh embryo transfer. This could be explained by a better embryo-endometrium synchrony achieved with endometrium preparation cycles.

Correlation of serum Anti-Müllerian hormone concentrations on day 3 of the in vitro fertilization stimulation cycle with assisted reproduction outcome in polycystic ovary syndrome patients

PURPOSE

To investigate whether serum Anti- Müllerian hormone (AMH) on day 3 could predict controlled ovarian stimulation and reproductive outcomes in women with polycystic ovary syndrome.

METHODS

A total of 164 PCOS patients undergoing their first IVF treatment cycle were prospectively included. Serum AMH levels on cycle day 3 was measured. The controlled ovarian stimulation and clinical outcomes for the study population were divided according to the <25th, 25 to 75th, or >75th percentile of serum day-3 AMH.

RESULTS

Estradiol levels on hCG day and the number of retrieved oocytes significantly increased with increasing serum AMH levels, while total consumption of gonadotropin dose showed a significant decrease (P < 0.05). Fertilization rate and the number of good quality embryos were comparable among the low, average and high groups (P > 0.05). Embryo implantation rates in the high AMH group was significantly inferior to those with low and average AMH concentration (27 versus 48.8 and 50%, P < 0.01). Clinical pregnancy rates was lower in the high AMH group than that of the low and average group (45.9 versus 65 and 66.7%, P = 0.09), but this difference was only close to statistical significance. In addition, ordinal regression analysis indicated that LH level was the only independent predictor of embryo implantation rates (P = 0.017).

CONCLUSIONS

In PCOS women, AMH levels on day 3 of the IVF stimulation cycle positively predict ovarian response to gonadotrophins. However, the women with high AMH levels had a significantly decreased IR, which may be due to remarkably increased LH concentrations.

A short narrative review of the feasibility of adopting mild ovarian stimulation for IVF as the current standard of care

INTRODUCTION

Mild ovarian stimulation has been conceived, proposed and implemented in clinical practice as a safer and cheaper alternative to conventional strategies of controlled ovarian hyperstimulation in preparation for in vitro fertilization (IVF). Our aim was to summarize the key evidence on this topic and explore its possible role as the standard treatment option for women undergoing IVF.

MATERIALS AND METHODS

A short narrative review of the existing literature, with emphasis on mild ovarian stimulation clinical and cost effectiveness, as well as treatment limitations.

RESULTS

Numerous studies highlight mild ovarian stimulation's favorable characteristics with respect to oocyte/embryo quality, reduced patient risk, and ease of intervention. There is, however, a need for high-quality laboratory environment. Limitations regarding poor responders, older women, or those seeking ovarian stimulation for non-infertility indications should also be considered. Finally, outcomes on the cumulative success rates and the cost effectiveness of mild ovarian stimulation remain inconclusive.

CONCLUSION

Mild ovarian stimulation protocols for IVF should currently be implemented only in carefully selected populations. Further research is needed to clarify the remaining controversies in this IVF approach.

Association of controlled ovarian hyperstimulation treatment with down-regulation of key regulators involved in embryonic implantation in mice

The debate exists whether or not gonadotropin-releasing hormone (GnRH) analogs used in controlled ovarian hyperstimulation (COH) impair endometrial receptivity. Homeobox A11 (Hoxa11), Meis homeobox 1 (Meis1), cadherin 1 (Cdh1), and catenin beta 1 (Ctnnb1) are well known to be involved in successful implantation. In this study, the endometrial expression of Hoxa11, Meis1, Cdh1, and Ctnnb1 during the peri-implantation period was investigated in an in vitro fertilization (IVF) mouse model by real-time RT-PCR and Western blot to evaluate the relationship between Hoxa11, Meis1, Cdh1, and Ctnnb1 expression and the impact of the COH on endometrial receptivity. The mimic COH protocols included GnRH agonist plus human menopausal gonadotropin (HMG) (GnRH agonist group), GnRH antagonist plus HMG (GnRH antagonist group), and HMG alone (HMG group). The expression levels of Hoxa11, Meis1, Cdh1, and Ctnnb1 mRNA and protein were decreased in all of the COH groups. The expression levels of Hoxa11 and Ctnnb1 were the lowest in the GnRH agonist group, and those of Meis1 and Cdh1 were lower in the GnRH analog groups than the HMG group. There were positive correlations between the expression of Hoxa11 and Ctnnb1, as well as the expression of Meis1 and Cdh1 among all the groups. In conclusion, the COH protocols, particularly with GnRH analogs, suppressed Hoxa11, Meis1, Ctnnb1 and Cdh1 expression, in mouse endometrium during the peri-implantation period. Our data reveal a novel molecular mechanism by which the COH protocols might impair endometrial receptivity.

Epigenetic control of development and expression of quantitative traits

In recent years, it has become increasingly clear that epigenetic regulation of gene expression is critical during embryo development and subsequently during pre- and post-natal life. The phenotype of an individual is the result of complex interactions between genotype and current, past and ancestral environment leading to a lifelong remodelling of its epigenome. Practically, if the genome was compared with the hardware in a computer, the epigenome would be the software that directs the computer's operation. This review points to the importance of epigenetic processes for genome function in various biological processes, such as embryo development and the expression of quantitative traits.

Hormone-induced delayed ovulation affects early embryonic development

OBJECTIVE

To analyze the effects of delayed ovulation on embryonic development in mice, because intrafollicular oocyte development may be delayed during assisted reproductive technology (ART) treatment in humans.

DESIGN

Experimental mouse study.

SETTING

University hospital.

ANIMAL(S)

Female C57Bl/6 mice.

INTERVENTION(S)

Cetrorelix is used as a GnRH-antagonist in ART treatments. To assess the effect of delayed ovulation on embryonic development, cetrorelix was applied concomitantly with follicle stimulation by pregnant mare serum gonadotropin. Ovulation was induced by hCG. Controls were stimulated with pregnant mare serum gonadotropin without delaying ovulation. Suppression of ovulation was assessed from the number of tertiary follicles, ruptured follicles, and corpora lutea in mouse ovaries after cetrorelix treatment. Number and weight of embryos and placentas, as well as number of resorption sites and dead embryos, was determined on day 17.5 of pregnancy.

MAIN OUTCOME MEASURE(S)

Inhibition of ovulation, embryonic development.

RESULT(S)

Cetrorelix inhibited ovulation in mice, as shown by an increase in number of tertiary follicles concomitant with a significant inhibition of follicle rupture and corpora lutea formation. Delayed ovulation caused by Cetrorelix treatment led to a significant increase in resorption sites and a significant decrease in embryonic weight of offspring.

CONCLUSION(S)

Preovulatory oocyte overripeness might have an effect on fertility and embryonic development during ART treatment.

The human cleavage stage embryo is a cradle of chromosomal rearrangements

The first cell cycles following in vitro fertilization (IVF) of human gametes are prone to chromosome instability. Many, but often not all, blastomeres of an embryo acquire a genetic makeup during cleavage that is not representative of the original zygotic genome. Whole chromosomes are missegregated, but also structural rearrangements of chromosomes do occur in human cleavage stage embryogenesis following IVF. Analysis of pre- and postnatal DNA samples indicates that the in vivo human conceptions also endure instability of chromosome number and structure during cleavage of the fertilized oocyte. This embryonic chromosome instability not necessarily undermines normal human development, but may lead to a spectrum of conditions, including loss of conception, genetic disease and genetic variation development. In this review, the structural instability of chromosomes during human cleavage stage embryogenesis is catalogued, channeled into etiologic models and linked to genomic profiles of healthy and diseased newborns.

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

BACKGROUND

Polycystic 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.

METHODS

For 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.

RESULTS

The 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.

CONCLUSIONS

Any 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.

Three-dimensional in vitro follicle growth: overview of culture models, biomaterials, design parameters and future directions

In vitro ovarian follicle culture is a new frontier in assisted reproductive technology with tremendous potential, especially for fertility preservation. Folliculogenesis within the ovary is a complex process requiring interaction between somatic cell components and the oocyte. Conventional two-dimensional culture on tissue culture substrata impedes spherical growth and preservation of the spatial arrangements between oocyte and surrounding granulosa cells. Granulosa cell attachment and migration can leave the oocyte naked and unable to complete the maturation process. Recognition of the importance of spatial arrangements between cells has spurred research in to three-dimensional culture system. Such systems may be vital when dealing with human primordial follicles that may require as long as three months in culture. In the present work we review pertinent aspects of in vitro follicle maturation, with an emphasis on tissue-engineering solutions for maintaining the follicular unit during the culture interval. We focus primarily on presenting the various 3-dimensional culture systems that have been applied for in vitro maturation of follicle:oocyte complexes. We also try to present an overview of outcomes with various biomaterials and animal models and also the limitations of the existing systems.

Assisted reproduction and its neuroendocrine impact on the offspring

Assisted reproductive technologies (ARTs) have been widely used during the last three decades and progressively more children are born with the help of such methods. There is now evidence that ARTs may be associated with slight epigenetic modifications in the expression of several genes that could have a long-term impact on the health of the offspring. Also, a clear association between such techniques and genomic imprinting abnormalities has been reported. The neuroendocrine impact of ART on the offspring includes slight elevations of systolic blood pressure (SBP) and diastolic blood pressure (DBP), as well as increased circulating triglyceride concentrations, in children born after ART, especially in those with rapid catch-up growth in weight during early childhood. However, the postnatal growth of most children after ART is normal and no increased incidence of the full metabolic syndrome has been observed in these children and adolescents. Moreover, the pace and timing of puberty of such children is normal and no increased incidence of premature adrenarche could be discerned in ART children in the absence of restricted fetal growth. Finally, a slight modification of the set point of thyroid stimulating hormone sensitivity was observed in ART children, without an apparent impact on thyroid hormone secretion. This has been attributed to epigenetic changes. Questions remain to be answered regarding the future reproductive capacity of children born after ART, as well as their cardiovascular risk in later adult life. Long-term prospective studies should be performed to provide robust evidence.