Isolation and expression of the human gametocyte-specific factor 1 gene (GTSF1) in fetal ovary, oocytes, and preimplantation embryos.

PURPOSE: Gametocyte-specific factor 1 has been shown in other species to be required for the silencing of retrotransposons via the Piwi-interacting RNA (piRNA) pathway. In this study, we aimed to isolate and assess expression of transcripts of the gametocyte-specific factor 1 (GTSF1) gene in the human female germline and in preimplantation embryos. METHODS: Complementary DNA (cDNA) libraries from human fetal ovaries and testes, human oocytes and preimplantation embryos and ovarian follicles isolated from an adult ovarian cortex biopsy were used to as templates for PCR, cloning and sequencing, and real time PCR experiments of GTSF1 expression. RESULTS: GTSF1 cDNA clones that covered the entire coding region were isolated from human oocytes and preimplantation embryos. GTSF1 mRNA expression was detected in archived cDNAs from staged human ovarian follicles, germinal vesicle (GV) stage oocytes, metaphase II oocytes, and morula and blastocyst stage preimplantation embryos. Within the adult female germline, expression was highest in GV oocytes. GTSF1 mRNA expression was also assessed in human fetal ovary and was observed to increase during gestation, from 8 to 21 weeks, during which time oogonia enter meiosis and primordial follicle formation first occurs. In human fetal testis, GTSF1 expression also increased from 8 to 19 weeks. CONCLUSIONS: To our knowledge, this report is the first to describe the expression of the human GTSF1 gene in human gametes and preimplantation embryos.

Variable imprinting of the MEST gene in human preimplantation embryos.

There is evidence that expression and methylation of the imprinted paternally expressed gene 1/mesoderm-specific transcript homologue (PEG1/MEST) gene may be affected by assisted reproductive technologies (ARTs) and infertility. In this study, we sought to assess the imprinting status of the MEST gene in a large cohort of in vitro-derived human preimplantation embryos, in order to characterise potentially adverse effects of ART and infertility on this locus in early human development. Embryonic genomic DNA from morula or blastocyst stage embryos was screened for a transcribed AflIII polymorphism in MEST and imprinting analysis was then performed in cDNA libraries derived from these embryos. In 10 heterozygous embryos, MEST expression was monoallelic in seven embryos, predominantly monoallelic in two embryos, and biallelic in one embryo. Screening of cDNA derived from 61 additional human preimplantation embryos, for which DNA for genotyping was unavailable, identified eight embryos with expression originating from both alleles (biallelic or predominantly monoallelic). In some embryos, therefore, the onset of imprinted MEST expression occurs during late preimplantation development. Variability in MEST imprinting was observed in both in vitro fertilization and intracytoplasmic sperm injection-derived embryos. Biallelic or predominantly monoallelic MEST expression was not associated with any one cause of infertility. Characterisation of the main MEST isoforms revealed that isoform 2 was detected in early development and was itself variably imprinted between embryos. To our knowledge, this report constitutes the largest expression study to date of genomic imprinting in human preimplantation embryos and reveals that for some imprinted genes, contrasting imprinting states exist between embryos.

Quantitative analysis of DNA methylation of imprinted genes in single human blastocysts by pyrosequencing.

We report the first quantitative assessment of DNA methylation for any gene in the human preimplantation embryo to reveal that imprints exist at KvDMR1, RB1, SNRPN, and GRB10 in the human blastocyst. For comparison, in two human embryonic stem cell lines, imprints were also observed at KvDMR1, SNRPN, GRB10, and other imprinted loci, whereas RB1 and MEG3 were hypermethylated.

Reducing the incidence of twins from IVF treatments: predictive modelling from a retrospective cohort.

BACKGROUND: IVF treatments carry a high risk of twin pregnancy which confers a higher risk to the mother and child than singletons. Increased use of elective single embryo transfer (eSET) can reduce this twin rate. We aimed to utilize a previously published data set and statistical model based on routinely collected clinical data to predict the outcomes of policies that increase the proportion of eSET. METHODS: The models allow simultaneous prediction of outcomes from double embryo transfer (DET) and SET. These models were used to predict outcomes for different scenarios using SET in both the initial (fresh) transfer and over a complete cycle (transfer of all embryos created, with cryopreservation). A total of 16 096 cycles (12 487 fresh and 3609 frozen) from 9040 couples treated between 2000 and 2005 were included in the final analyses. RESULTS: For any transfer, SET has about a one-third lower live birth rate relative to DET: this can be partially mitigated by appropriate patient and treatment cycle selection, with several realistic policies performing similarly. However, if we consider complete cycles with embryo cryopreservation, it is possible for repeat SET to produce more live births per egg retrieval than repeat DET. CONCLUSIONS: All patients receiving SET would have a higher chance of successful treatment in that cycle if they received DET. The selection of appropriate patients for SET can partially ameliorate the overall loss. For complete cycles, repeat SET could produce more live births per egg retrieval than repeat DET. All treatments involving SET will increase the number of treatments required to achieve a successful outcome and this extra treatment burden will be a significant barrier to the implementation of such treatments.

Association between amino acid turnover and chromosome aneuploidy during human preimplantation embryo development in vitro.

This study investigated the relationship between human preimplantation embryo metabolism and aneuploidy rates during development in vitro. One hundred and eighty-eight fresh and cryopreserved embryos from 59 patients (33.9 +/- 0.6 years) were cultured for 2-5 days. The turnover of 18 amino acids was measured in spent media by high-performance liquid chromatography. Embryos were either fixed for interphase fluorescent in situ hybridization analysis of chromosomes 13, 18, 19, 21, X or Y, or were assayed for mitochondrial activity. Amino acid turnover was different (P < 0.05) between stage-matched fresh and cryopreserved embryos due to blastomere loss following warming. The proportion of embryos with aneuploid cells increased as cell division progressed from pronucleate- (23%) to late cleavage stages (50-70%). Asparagine, glycine and valine turnover was significantly different between uniformly genetically normal and uniformly abnormal embryos on Days 2-3 of culture. By Days 3-4, the profiles of serine, leucine and lysine differed between uniformly euploid versus aneuploid embryos. Gender significantly (P < 0.05) affected the metabolism of tryptophan, leucine and asparagine by cleavage-stage embryos. Pronucleate zygotes had a significantly higher proportion of active:inactive mitochondria compared with cleavage-stage embryos. Furthermore, mitochondrial activity was correlated (P < 0.05) with altered aspartate and glutamine turnover. These results demonstrate the association between the metabolism, cytogenetic composition and health of human embryos in vitro.

Elective single embryo transfer: guidelines for practice British Fertility Society and Association of Clinical Embryologists.

Assisted conception treatment is the single most important cause in the increase in multiple pregnancy and births over the last 25 years. Multiple births are associated with significant peri natal morbidity and mortality. Europe has led the way in reducing multiple births by widespread adoption of an elective single embryo policy, which in Belgium is linked to an increase in state funding. Randomized controlled trials suggest that an eSET policy must include the ability to cryopreserve and transfer any remaining quality embryos to obtain parity with a double embryo transfer. This document provides a review of the available evidence with guidelines for practice, to help facilitate the introduction of an eSET policy in the UK.

Principal findings from a multicenter trial investigating the safety of follicular-fluid meiosis-activating sterol for in vitro maturation of human cumulus-enclosed oocytes.

OBJECTIVE: To evaluate the safety of applying follicular-fluid meiosis-activating sterol (FF-MAS) in vitro to immature human oocytes. DESIGN: Phase I bicenter, randomized, parallel-group, controlled, partially blinded trial. SETTING: Third-level referral academic centers, including reproductive biology and genetics laboratories. PATIENTS: Endocrinologically normal women with a medical indication for IVF or intracytoplasmic sperm injection, or healthy volunteers. INTERVENTION(S): Subjects were randomized at a ratio 1 to 6 into either conventional GnRH-agonist and recombinant FSH stimulation (IVO) for oocyte retrieval, or minimally stimulated in vitro maturation (IVM) with the use of recombinant FSH. Retrieved immature oocyte cumulus complexes were cultured for 30 or 36 hours in one of six IVM culture conditions containing FF-MAS (range, 0.1-20 microM). Polar body-extruded oocytes from the IVO and IVM groups were processed for chromosomal analysis. MAIN OUTCOME MEASURE(S): The primary endpoint was the incidence of metaphase II stage oocytes with numeric chromosomal abnormalities, using full (spectral karyotyping) or partial (fluorescent in situ hybridization with seven probes) karyotyping or Giemsa count. A secondary objective was to document the frequency of metaphase II oocytes after IVM with FF-MAS supplements. RESULT(S): Oocyte cumulus complexes obtained from the IVO (mean, 8.9) and IVM (mean, 6.2) groups had equal maturation rates. Compared to IVO, exposure of germinal-vesicle oocytes for a maturation period of 30 hours did not increase aneuploidy. An exposure period of 36 hours doubled the aneuploidy rate, but this was significant only for the 20-muM dose of FF-MAS. CONCLUSION: Inclusion of 1-10 microM FF-MAS in a 30-hour IVM protocol is safe.

Comparison of effects of zona drilling by non-contact infrared laser or acid Tyrode's on the development of human biopsied embryos as revealed by blastomere viability, cytoskeletal analysis and molecular cytogenetics.

Use of a non-contact infrared laser (IRL) or acid Tyrode's for zona drilling before embryo biopsy was compared by assessing blastomere viability using various fluorescent markers or culture of the single biopsied blastomere, and, by cytoskeletal and molecular cytogenetic analysis of the biopsied embryos following culture to the blastocyst stage. There was no significant difference in the proportion of biopsied embryos that showed no damage in both the biopsied blastomere and in the remaining embryo (acid Tyrode's: 75% versus IRL: 68%), or in the proportion of single biopsied blastomeres that divided in culture (P > 0.05). However, single biopsied blastomeres from laser drilled embryos showed a greater tendency to form miniblastocysts. The proportion of laser or acid Tyrode's biopsied embryos that reached the blastocyst stage by day 6 was similar, although evident earlier (day 5) in the laser biopsied embryos. Spindle abnormalities at the blastocyst stage included tripolar and tetrapolar spindles, but their incidence was not significantly different from controls. In addition, no significant difference was observed in the incidence of chromosomal abnormalities and mosaicism between the two groups. It is concluded that using an IRL at a safe working distance does not cause adverse immediate or longer term effects on the development of human biopsied embryos, although damage can occur if drilling within this distance is unavoidable. Acid Tyrode's drilling can also cause damage, and tended to retard blastocyst development.

The predictive value of the "Hull & Rutherford" classification for tubal damage.

OBJECTIVE: This study explores the predictive value for live birth following tubal reconstructive surgery of the "Hull & Rutherford" (H&R) classification system. DESIGN: Retrospective cohort study. SETTING: Tertiary infertility referral service, University of Bristol. POPULATION: Infertile women younger than 40 years with tubal damage undergoing tubal surgery. METHODS: Women (n= 192) were grouped according to three severity grades of disease based on the H&R classification. Essentially, the main features of grade I tubal damage were filmy adhesions, whereas grades II and III referred to unilateral severe damage and bilateral severe damage, respectively. Standard surgical techniques were employed. Pregnancy and live birth rates were calculated and compared using time-specific univariate Kaplan-Maier curves and multivariate Cox's regression analysis. MAIN OUTCOME MEASURES: Pregnancy, ectopic and live birth within three years of surgery. RESULTS: A significant trend towards higher ectopic pregnancy rates (P < 0.001) with increasing severity of tubal damage was noted, but not miscarriage rates. Univariate analysis revealed significant differences in the live birth rates of 69%, 48% and 9% for grades I, II and III, respectively. Multivariate analysis (controlling for age, duration of and primary infertility) confirmed these differences to be significant with risk ratios of 13.7 (95% CI: 4.49-41.9) and 6.54 (95% CI: 2.48-17.24) for grades I and II disease, respectively, compared with grade III disease, used as the reference. CONCLUSIONS: The H&R classification is a simple classification system that is able to distinguish women into three distinct groups giving a favourable, fair and poor prognosis for live birth following tubal surgery.

Isothermal whole genome amplification from single and small numbers of cells: a new era for preimplantation genetic diagnosis of inherited disease.

Preimplantation genetic diagnosis (PGD) of single gene defects following assisted conception typically involves removal of single cells from preimplantation embryos and analysis using highly sensitive PCR amplification methods taking stringent precautions to prevent contamination from foreign or previously amplified DNA. Recently, whole genome amplification has been achieved from small quantities of genomic DNA by isothermal amplification with bacteriophage 29 DNA polymerase- and exonuclease-resistant random hexamer primers. Here we report that isothermal whole genome amplification from single and small numbers of lymphocytes and blastomeres isolated from cleavage stage embryos yielded microgram quantities of amplified DNA, and allowed analysis of 20 different loci, including the DeltaF508 deletion causing cystic fibrosis and polymorphic repeat sequences used in DNA fingerprinting. As with analysis by PCR-based methods, some preferential amplification or allele drop-out at heterozygous loci was detected with single cells. With 2-5 cells, amplification was more consistent and with 10 or 20 cells results were indistinguishable from genomic DNA. The use of isothermal whole genome amplification as a universal first step marks a new era for PGD since, unlike previous PCR-based methods, sufficient DNA is amplified for diagnosis of any known single gene defect by standard methods and conditions.

A randomized, double-blind, multicentre clinical trial comparing starting doses of 150 and 200 IU of recombinant FSH in women treated with the GnRH antagonist ganirelix for assisted reproduction.

BACKGROUND: Studies with the GnRH antagonist ganirelix in assisted reproduction have indicated that compared with traditional GnRH agonist downregulation protocols, slightly fewer oocytes are retrieved. In this study it was investigated whether an increase in the starting dose of recombinant FSH (rFSH) could compensate for this loss. METHODS: A randomized, double-blind, multicentre clinical trial comparing a starting dose of 150 and 200 IU of rFSH (follitropin beta), in women undergoing treatment with the GnRH antagonist ganirelix. RESULTS: In total, 257 women were treated with rFSH, of whom 131 received 150 IU and 126 women 200 IU. Overall, 10.3 oocytes were retrieved in the 150 IU group and 11.9 in the 200 IU group (P=0.051). This difference became significant when women with cycle cancellation before HCG administration were excluded. Nearly 500 IU of additional rFSH was given in the high-dose group (2014 versus 1541 IU). In the low-dose group, 4.6 high-quality embryos were obtained compared with 4.5 in the high-dose group. Vital pregnancy rates were similar (31 and 25% in the 150 and 200 IU-treated women, respectively). Serum concentrations of FSH, estradiol and progesterone were significantly higher in the high-dose group at day 6 of rFSH treatment and on the day of HCG administration. In the high-dose group, serum LH concentrations were higher at day 6 of rFSH treatment but lower at the day of HCG administration. CONCLUSION: By increasing the starting dose from 150 to 200 IU of rFSH, slightly more oocytes can be retrieved in GnRH antagonist protocols for assisted reproduction. However, because this did not translate into a higher number of high quality embryos, the clinical relevance of such a dose increase may be questioned.

Karyotyping of human metaphase II oocytes by multifluor fluorescence in situ hybridization.

OBJECTIVE: To quantify aneuploidy in inseminated, injected, and noninjected oocytes from infertility patients using Multifluor fluorescence in situ hybridization (M-FISH). DESIGN: Prospective study. SETTING: Reproductive biology group, academic unit of pediatrics, obstetrics, and gynecology. PATIENT(S): Forty-eight patients undergoing ovarian stimulation and either intracytoplasmic sperm injection (ICSI) or conventional in vitro fertilization (IVF). INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): M-FISH karyotyping of 67 metaphase II oocytes, including noninjected in vitro matured oocytes, and injected inseminated-failed fertilized oocytes. RESULT(S): Thirty-nine percent of oocytes were aneuploid, with nondisjunction of chromosomes in 34% of oocytes and predivision of chromatids in 10%. There was no difference in aneuploidy rates between ICSI noninjected in vitro matured oocytes and injected, failed fertilized oocytes. Chromosomes most frequently involved in aneuploidy were 15, 18, 19, 22, and X. In seven injected ICSI MII oocytes, the prematurely condensed sperm chromatin was karyotyped by M-FISH. CONCLUSION(S): M-FISH was used to diagnose aneuploidy at maternal meiosis I in 39% of oocytes, and M-FISH karyotyping of sperm was demonstrated.

Rates of bacterial vaginosis in women undergoing in vitro fertilisation for different types of infertility.

OBJECTIVE: To assess whether the rate of bacterial vaginosis (BV) is higher in women with tubal factor infertility compared with those with other causes of infertility. DESIGN: Cross-sectional study. SETTING: Assisted conception unit of a teaching hospital in Leeds. POPULATION: Consecutive women undergoing in vitro fertilisation. METHODS: Women undergoing in vitro fertilisation (IVF) had a vaginal smear taken at the time of their egg collection. The smear was Gram-stained and graded as normal, intermediate or BV. MAIN OUTCOME MEASURES: The presence of bacterial vaginosis and the causes of infertility. RESULTS: A total of 749 women were included. The vaginal smears were normal in 63.6%, intermediate in 12.1%, and BV in 24.3%. The rates of BV in women with different types of infertility were 36.4% in tubal factor, 15.6% in male factor, 33.3% in anovulation, 12.5% in endometriosis and 18.9% in unexplained infertility. After controlling for the effects of age and smoking using a multivariate logistic regression model, women with tubal infertility were significantly more likely to have BV than women with endometriosis OR 3.63 (95% CI 1.52-8.67); male factor OR 2.98 (95% CI 1.80-4.90); and unexplained infertility OR 2.20 (95% CI 1.35-3.59). The adjusted figures for the increase of BV in women with anovulation were: endometriosis OR 3.77 (95% CI 1.28-11.08); male factor OR 3.09 (95% CI 1.37-6.96); and unexplained infertility OR 2.29 (95% CI 1.02-5.12). CONCLUSIONS: Women with tubal infertility were three times more likely to have BV than women with endometriosis, male factor or unexplained infertility. These findings support the association between BV, pelvic inflammatory disease (PID) and tubal damage but do not help distinguish between cause and effect. Women with anovulation were also three times more likely to have BV than women with endometriosis or male factor infertility, supporting suggestions of hormonal influence on vaginal flora.

Non-invasive amino acid turnover predicts human embryo developmental capacity.

BACKGROUND: IVF is limited by low success rates and a confounding high multiple birth rate contributing to prematurity, increased neonatal mortality and child handicap. These problems could be overcome if single embryos of known developmental competence could be selected for transfer on day 2/3 of development, but current methods, which rely on morphological appearance, are poor predictors of viability. METHODS: We have measured non-invasively the depletion/appearance (i.e. turnover) of a physiological mixture of 18 amino acids by single human embryos during in-vitro culture using high performance liquid chromatography. RESULTS: From the time of transfer (day 2/3), embryos with future competence to develop to the blastocyst stage (day 5/6) exhibit amino acid flux patterns distinct from those of embryos with similar morphological appearance which arrest. Significantly, the profiles of Ala, Arg, Gln, Met and Asn flux predict blastocyst potentiality at >95%. The amino acid most consistently depleted throughout development by those embryos which form blastocysts was leucine. Of the amino acids which were produced, the most striking was alanine, which appeared in increasing amounts throughout development. CONCLUSIONS: Non-invasive amino acid profiling has the potential to select developmentally competent single embryos for transfer, thereby increasing the success rate and eliminating multiple births in IVF.