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Preview: Human Reproduction - Advance Access

Human Reproduction Advance Access

Published: Sat, 23 Sep 2017 00:00:00 GMT

Last Build Date: Sat, 23 Sep 2017 01:48:25 GMT


Genome stability of bovine in vivo -conceived cleavage-stage embryos is higher compared to in vitro -produced embryos


AbstractSTUDY QUESTIONIs the rate and nature of chromosome instability (CIN) similar between bovine in vivo-derived and in vitro-cultured cleavage-stage embryos?SUMMARY ANSWERThere is a major difference regarding chromosome stability of in vivo-derived and in vitro-cultured embryos, as CIN is significantly lower in in vivo-derived cleavage-stage embryos compared to in vitro-cultured embryos.WHAT IS KNOWN ALREADYCIN is common during in vitro embryogenesis and is associated with early embryonic loss in humans, but the stability of in vivo-conceived cleavage-stage embryos remains largely unknown.STUDY DESIGN, SIZE, DURATIONBecause human in vivo preimplantation embryos are not accessible, bovine (Bos taurus) embryos were used to study CIN in vivo. Five young, healthy, cycling Holstein Friesian heifers were used to analyze single blastomeres of in vivo embryos, in vitro embryos produced by ovum pick up with ovarian stimulation (OPU-IVF), and in vitro embryos produced from in vitro matured oocytes retrieved without ovarian stimulation (IVM-IVF).PARTICIPANTS/MATERIALS, SETTING, METHODSSingle blastomeres were isolated from embryos, whole-genome amplified and hybridized on Illumina BovineHD BeadChip arrays together with the bulk DNA from the donor cows (mothers) and the bull (father). DNA was also obtained from the parents of the bull and from the parents of the cows (paternal and maternal grandparents, respectively). Subsequently, genome-wide haplotyping and copy-number profiling was applied to investigate the genomic architecture of 171 single bovine blastomeres of 16 in vivo, 13 OPU-IVF and 13 IVM-IVF embryos.MAIN RESULTS AND THE ROLE OF CHANCEThe genomic stability of single blastomeres in both of the in vitro-cultured embryo cohorts was severely compromised (P < 0.0001), and the frequency of whole chromosome or segmental aberrations was higher in embryos produced in vitro than in embryos derived in vivo. Only 18.8% of in vivo-derived embryos contained at least one blastomere with chromosomal anomalies, compared to 69.2% of OPU-IVF embryos (P < 0.01) and 84.6% of IVM-IVF embryos (P < 0.001).LARGE SCALE DATAGenotyping data obtained in this study has been submitted to NCBI Gene Expression Omnibus (GEO; accession number GSE95358)LIMITATIONS REASONS FOR CAUTIONThere were two main limitations of the study. First, animal models may not always reflect the nature of human embryogenesis, although the use of an animal model to investigate CIN was unavoidable in our study. Second, a limited number of embryos were obtained, therefore more studies are warranted to corroborate the findings.WIDER IMPLICATIONS OF THE FINDINGSAlthough CIN is also present in in vivo-developed embryos, in vitro procedures exacerbate chromosomal abnormalities during early embryo development. Hence, the present study highlights that IVF treatment compromises embryo viability and should be applied with care. Additionally, our results encourage to refine and improve in vitro culture conditions and assisted reproduction technologies.STUDY FUNDING/COMPETING INTEREST(S)The study was funded by the Agency for Innovation by Science and Technology (IWT) (TBM-090878 to J.R.V. and T.V.), the Research Foundation Flanders (FWO; G.A093.11 N to T.V. and J.R.V. and G.0392.14 N to A.V.S. and J.R.V.), the European Union’s FP7 Marie Curie Industry-Academia Partnerships and Pathways (IAPP, SARM, EU324509 to J.R.V., T.V., O.T, A.D., A.S. and A.K.) and Horizon 2020 innovation programme (WIDENLIFE, 692065 to J.R.V., O.T., T.V., A.K. and A.S.). M.Z.E., J.R.V. and T.V. are co-inventors on a patent application ZL913096-PCT/EP2014/068315-WO/2015/028576 (‘Haplotyping and copy-number typing using polymorphic variant allelic frequencies’), licensed to Cartagenia (Agilent Technologies).[...]

Clinical implications of mitochondrial DNA quantification on pregnancy outcomes: a blinded prospective non-selection study


Can quantification of mitochondrial DNA (mtDNA) in trophectoderm (TE) biopsy samples provide information concerning the viability of a blastocyst, potentially enhancing embryo selection and improving IVF treatment outcomes?
This study demonstrated that euploid blastocysts of good morphology, but with high mtDNA levels had a greatly reduced implantation potential.
Better methods of embryo selection leading to IVF outcome improvement are necessary, as the transfer of chromosomally normal embryos of high morphological grade cannot guarantee the establishment of an ongoing pregnancy. The quantity of mtDNA in embryonic cells has been proposed as a new biomarker of viability—higher levels of mtDNA associated with reduced implantation potential.
mtDNA was quantified in 199 blastocysts, previously biopsied and shown to be chromosomally normal using preimplantation genetic testing for aneuploidy (PGT-A). These were generated by 174 couples (average female age 37.06 years). All patients underwent IVF in a single clinic. The study took place in a blinded, non-selection manner—i.e. mtDNA quantity was not known at the time of single embryo transfer. The fate of the embryos transferred was subsequently compared to the mtDNA levels measured.
Embryos were biopsied at the blastocyst stage. The TE samples obtained were subjected to whole genome amplification followed by comprehensive chromosome analysis via next generation sequencing. The same biopsy specimens were also tested using quantitative PCR, allowing highly accurate mtDNA quantification. After blastocyst transfer, the code used for blinding was broken and analysis undertaken to reveal whether the amount of mtDNA had any association with embryo implantation.
mtDNA analysis of the 199 blastocysts revealed that 9 (5%) contained unusually high levels of mtDNA. All embryo transfers involved a single chromosomally normal blastocyst of good morphology. Of these, 121 (60%) led to ongoing pregnancies, 11(6%) led to biochemical pregnancies, and 10 (5%) spontaneously miscarried. All (100%) of these blastocysts had mtDNA levels considered to be normal/low. The remaining 57 (29%) blastocysts failed to implant. Among these non-viable embryos there were 9 (16%) with unusually high levels of mtDNA. This meant that the ongoing pregnancy rate for morphologically good, euploid blastocysts, with normal/low levels of mtDNA was 64% (121/190). In contrast, the ongoing pregnancy rate for the same type of embryos, but with elevated mtDNA levels, was 0/9 (0%). This difference was highly statistically significant (P < 0.0001).
To determine the true extent of any clinical benefits a randomized clinical trial will be necessary. Research is needed to improve understanding of the biology of mtDNA expansion.
This is the first investigation to evaluate the clinical impact of increased mtDNA in a prospective blinded manner. Results confirm that embryos with elevated mtDNA rarely implant, supporting its use as a viability biomarker. A total of 64% of euploid blastocysts with normal/low mtDNA implanted versus 60% for the cohort as a whole.
This study was supported by institutional funding (Reprogenetics UK and Reprogenetics). DW is supported by the National Institute for Health Research (NIHR) Oxford Biomedical Research Centre Programme. None of the authors have any competing interests.

Corifollitropin alfa followed by highly purified HMG versus recombinant FSH in young poor ovarian responders: a multicentre randomized controlled clinical trial


AbstractSTUDY QUESTIONDoes administration of corifollitropin alfa followed by highly purified (hp) HMG result in higher ongoing pregnancy rates compared with daily recombinant FSH (rFSH) in young poor responders?SUMMARY ANSWERCorifollitropin alfa followed by hp-HMG does not increase ongoing pregnancy rates compared with rFSH in young poor responders, although more supernumerary cryopreserved embryos were obtained with corifollitropin alfa and hp-HMG.WHAT IS KNOWN ALREADYPoor ovarian response remains one of the main therapeutic challenges in women undergoing ovarian stimulation, given that very low live birth rates of 6% have been reported in this particular group of infertile patients. Nevertheless, concerns have been raised that a degree of heterogeneity remains, as the prognostic effect of individual factors is still unclear, particularly for the young poor responder group. The rationale for conducting the current randomized trial was based on the results of a previous pilot study demonstrating promising results with the administration of hp-HMG following corifollitropin alpha in women younger than 40 years of age, fulfilling the ‘Bologna’ criteria.STUDY DESIGN, SIZE, DURATIONA multicenter, phase III, superiority, randomized trial was conducted using a parallel two-arm design. The study included 152 patients younger than 40 years old and fulfilling the ‘Bologna’ criteria for poor ovarian response, from one tertiary referral centre in Europe and one tertiary referral centre in Asia. Enrolment was performed from March 2013 to May 2016.PARTICIPANTS/MATERIALS, SETTING, METHODSEligible patients were randomized to either administration of 150 μg corifollitropin alfa followed by 300 IU hp-HMG (Group A) or to 300 IU of daily recombinant FSH (Group B) in a fixed GnRH antagonist protocol. The randomization sequence was created using a computer generated randomization list stratified by centre, using 1:1 allocation. The primary outcome was ongoing pregnancy rate (defined as the presence of an intrauterine gestational sac with an embryonic pole demonstrating cardiac activity at 9–10 weeks of gestation). Secondary outcomes included embryo cryopreservation rates, clinical and biochemical pregnancy rates and number of oocytes retrieved.MAIN RESULTS AND THE ROLE OF CHANCEOverall, 152 poor ovarian responders defined by the ‘Bologna’ criteria were included in the study. Using an intention-to treat analysis, the ongoing pregnancy rates did not differ significantly between Group A 11/77 (14.3%) and Group B 11/70 (15.7%), absolute difference: −0.4 (−11.5 to 10.8), OR = 0.9 (0.4–2.4). Biochemical and clinical pregnancy rates, live birth rates and the number of oocytes retrieved were also comparable between the two groups. Nevertheless, more patients in the corifollitropin alfa group had cryopreserved embryos compared to the rFSH group [22 (28.6%) versus 10 (14.3%), OR = 2.4 (1.01–5.5)]. Incidentally, Asian patients had significantly lower cancellation rates compared to European poor responders [2/64 (3.1%) versus 17/83 (20.4%), OR = 0.12 (0.03–0.5)]. This discrepancy could be explained by the fact that Asian women were better prognosis patients than European patients, with significantly lower FSH [9.8 (5.3) versus 11.5 (5.4), P = 0.017] and significantly higher AMH [1.1 (0.9) versus 0.4 (0.3), P-value <0.001] levels.LIMITATIONS, REASONS FOR CAUTIONOngoing pregnancy rates close to 14% for both treatment groups differ significantly from the hypothesized primary outcome rates used in the power calculation. Therefore, our randomized trial might have been underpowered to detect smaller differences. The use of multiple secondary outcomes and multiple comparisons could have increased a Type 1 error. Finally, although the chance of selection biases remains low given the nature of the infertile population, the open-label design could have been a limitation.WIDER IMPLICATIONS OF THE FINDINGSPoor ovarian response represents a challenge and although a specific protocol m[...]

Cumulative live birth rates following miscarriage in an initial complete cycle of IVF: a retrospective cohort study of 112 549 women


AbstractSTUDY QUESTIONIn women undergoing IVF/ICSI who miscarry in their first complete cycle, what is the chance of a live birth in subsequent complete cycles, and how does this compare with those whose first complete cycle ends with live birth or without a pregnancy?SUMMARY ANSWERAfter two further complete cycles of IVF/ICSI, women who had miscarried or had a live birth in their first complete cycle had a higher chance of live birth (40.9 and 49.0%, respectively) than those who had no pregnancies (30.1%).WHAT IS KNOWN ALREADYCumulative live birth rates (CLBRs) after one or more complete cycles of IVF have been reported previously, as have some of the risk factors associated with miscarriage, both in general populations and in those undergoing IVF. Chances of cumulative live birth after a number of complete IVF cycles involving replacement of fresh followed by frozen embryos after an initial miscarriage in a population undergoing IVF treatment have not been reported previously.STUDY DESIGN, SIZE, DURATIONNational population-based cohort study of 112 549 women who started their first IVF treatment between 1999 and 2008.PARTICIPANTS/MATERIALS, SETTING, METHODSData from the UK Human Fertilisation and Embryology Authority (HFEA) register on IVF/ICSI treatments, using autologous gametes were analysed. CLBRs were estimated in women who (i) had miscarriage (and no live birth), (ii) at least one live birth or (iii) no pregnancy in their first complete cycle of IVF/ICSI (including fresh and frozen embryo transfers following a single oocyte retrieval episode). A multivariable analysis was performed to assess the effect of first complete cycle outcome on subsequent CLBRs after adjusting for confounding factors such as female age, duration of infertility and cause of infertility.MAIN RESULTS AND THE ROLE OF CHANCEIn their first complete cycle, 9321 (8.3%) women had at least one miscarriage (and no live birth); 33 152 (29.5%) had at least one live birth and 70 076 (62.3%) had no pregnancies. After two further complete cycles, conservative CLBRs (which assume that women who discontinued treatment subsequently never had a live birth) were 40.9, 49.0 and 30.1%, while optimal CLBRs (which assume that women who discontinue have the same chance of live birth as those treated) were 49.5, 57.9 and 38.4% in the miscarriage, live birth and no pregnancy groups respectively. Odds of cumulative live birth for women who miscarried in their first complete cycle were 42% higher than those who had no pregnancy [odds ratio (95% CI) = 1.42 (1.34, 1.50)], and twice as high for live birth versus no pregnancy [2.04 (1.89, 2.20)]. Negative predictors for live birth in all women included tubal infertility [0.88 (0.82, 0.94)] and increasing age [18–40 years = 0.94 (0.94, 0.95); >40 years = 0.63 (0.59, 0.66) per year].LIMITATIONS AND REASON FOR CAUTIONCLBRs could not be estimated for treatments occurring after September 2008 due to potentially incomplete data following regulatory changes regarding consent for data use in research. Additionally, covariates not included in the HFEA database (including BMI, smoking, previous history of miscarriage and gestational age at miscarriage) could not be adjusted for in our analysis.WIDER IMPLICATIONS OF THE FINDINGSMiscarriage following IVF can be devastating for couples who are uncertain about their ultimate prognosis. Our findings will provide reassurance to these couples as they consider their options for continuing treatment.STUDY FUNDING/COMPETING INTEREST(S)N.J.C. received an Aberdeen Summer Research Scholarship funded by the Institute of Applied Health Sciences (University of Aberdeen), through the Aberdeen Clinical Academic Training Scheme. This work was supported by a Chief Scientist Office Postdoctoral Training Fellowship in Health Services Research and Health of the Public Research (Ref PDF/12/06). The views expressed here are those of the authors and not necessarily those of the Chief Scientist Office or the University of[...]