We report studies of preimplantation human embryo development that correlate time-lapse image analysis and gene expression profiling. By examining a large set of zygotes from in vitro fertilization (IVF), we find that success in progression to the blastocyst stage can be predicted with >93% sensitivity and specificity by measuring three dynamic, noninvasive imaging parameters by day 2 after fertilization, before embryonic genome activation (EGA). These parameters can be reliably monitored by automated image analysis, confirming that successful development follows a set of carefully orchestrated and predictable events. Moreover, we show that imaging phenotypes reflect molecular programs of the embryo and of individual blastomeres. Single-cell gene expression analysis reveals that blastomeres develop cell autonomously, with some cells advancing to EGA and others arresting. These studies indicate that success and failure in human embryo development is largely determined before EGA. Our methods and algorithms may provide an approach for early diagnosis of embryo potential in assisted reproduction.

Non-invasive imaging of human embryos before embryonic genome activation predicts development to the blastocyst stage

There has been a sharp increase in the demand for fertility preservation. This review summarizes the indications and current options and describes new techniques and strategies, including those for women with newly diagnosed malignant disease.

https://www.nejm.org/doi/suppl/10.1056/NEJMra1614676/suppl_file/nejmra1614676_appendix.pdf

Fertility Preservation in Women

Survival and development of human embryos was compared following slow cooling versus vitrification involving more than 13,000 vitrified embryos. In addition, the efficacy of an open system, the Cryotop, and a closed vitrification system, the CryoTip™, were compared using human blastocysts. One hundred percent of vitrified human pronuclear stage embryos survived and 52% developed to blastocysts as compared with 89% survival and 41% blastocyst development after slow cooling. Similar survival rates were seen with vitrification of 4-cell embryos (98%) as compared with slow cooling (91%). Furthermore, 90% of vitrified blastocysts survived and resulted in a 53% pregnancy rate following transfer, as compared with 84% survival and 51% pregnancy rates following slow cooling. All corresponding values were significantly different. When the closed and open vitrification systems were compared, no difference was found with regard to supporting blastocyst survival (93 and 97% for CryoTip and Cryotop respectively), pregnancies (51 versus 59% respectively) and deliveries (48 versus 51% respectively). Vitrification is a simple, efficient and cost-effective way to improve cumulative pregnancy rates per cycle. The use of the closed CryoTip system eliminates the potential for embryo contamination during cryopreservation and storage without compromising survival and developmental rates in vitro and in vivo.

https://www.rbmojournal.com/article/S1472-6483(10)61169-8/pdf

Comparison of open and closed methods for vitrification of human embryos and the elimination of potential contamination

BACKGROUND Successful cryopreservation of oocytes and embryos is essential not only to maximize the safety and efficacy of ovarian stimulation cycles in an IVF treatment, but also to enable fertility preservation. Two cryopreservation methods are routinely used: slow-freezing or vitrification. Slow-freezing allows for freezing to occur at a sufficiently slow rate to permit adequate cellular dehydration while minimizing intracellular ice formation. Vitrification allows the solidification of the cell(s) and of the extracellular milieu into a glass-like state without the formation of ice. OBJECTIVE AND RATIONALE The objective of our study was to provide a systematic review and meta-analysis of clinical outcomes following slow-freezing/thawing versus vitrification/warming of oocytes and embryos and to inform the development of World Health Organization guidance on the most effective cryopreservation method. SEARCH METHODS A Medline search was performed from 1966 to 1 August 2016 using the following search terms: (Oocyte(s) [tiab] OR (Pronuclear[tiab] OR Embryo[tiab] OR Blastocyst[tiab]) AND (vitrification[tiab] OR freezing[tiab] OR freeze[tiab]) AND (pregnancy[tiab] OR birth[tiab] OR clinical[tiab]). Queries were limited to those involving humans. RCTs and cohort studies that were published in full-length were considered eligible. Each reference was reviewed for relevance and only primary evidence and relevant articles from the bibliographies of included articles were considered. References were included if they reported cryosurvival rate, clinical pregnancy rate (CPR), live-birth rate (LBR) or delivery rate for slow-frozen or vitrified human oocytes or embryos. A meta-analysis was performed using a random effects model to calculate relative risk ratios (RR) and 95% CI. OUTCOMES One RCT study comparing slow-freezing versus vitrification of oocytes was included. Vitrification was associated with increased ongoing CPR per cycle (RR = 2.81, 95% CI: 1.05-7.51; P = 0.039; 48 and 30 cycles, respectively, per transfer (RR = 1.81, 95% CI 0.71-4.67; P = 0.214; 47 and 19 transfers) and per warmed/thawed oocyte (RR = 1.14, 95% CI: 1.02-1.28; P = 0.018; 260 and 238 oocytes). One RCT comparing vitrification versus fresh oocytes was analysed. In vitrification and fresh cycles, respectively, no evidence for a difference in ongoing CPR per randomized woman (RR = 1.03, 95% CI: 0.87-1.21; P = 0.744, 300 women in each group), per cycle (RR = 1.01, 95% CI: 0.86-1.18; P = 0.934; 267 versus 259 cycles) and per oocyte utilized (RR = 1.02, 95% CI: 0.82-1.26; P = 0.873; 3286 versus 3185 oocytes) was reported. Findings were consistent with relevant cohort studies. Of the seven RCTs on embryo cryopreservation identified, three met the inclusion criteria (638 warming/thawing cycles at cleavage and blastocyst stage), none of which involved pronuclear-stage embryos. A higher CPR per cycle was noted with embryo vitrification compared with slow-freezing, though this was of borderline statistical significance (RR = 1.89, 95% CI: 1.00-3.59; P = 0.051; three RCTs; I2 = 71.9%). LBR per cycle was reported by one RCT performed with cleavage-stage embryos and was higher for vitrification (RR = 2.28; 95% CI: 1.17-4.44; P =  0.016; 216 cycles; one RCT). A secondary analysis was performed focusing on embryo cryosurvival rate. Pooled data from seven RCTs (3615 embryos) revealed a significant improvement in embryo cryosurvival following vitrification as compared with slow-freezing (RR = 1.59, 95% CI: 1.30-1.93; P < 0.001; I2 = 93%). WIDER IMPLICATIONS Data from available RCTs suggest that vitrification/warming is superior to slow-freezing/thawing with regard to clinical outcomes (low quality of the evidence) and cryosurvival rates (moderate quality of the evidence) for oocytes, cleavage-stage embryos and blastocysts. The results were confirmed by cohort studies. The improvements obtained with the introduction of vitrification have several important clinical implications in ART. Based on this evidence, in particular regarding cryosurvival rates, laboratories that continue to use slow-freezing should consider transitioning to the use of vitrification for cryopreservation.

Oocyte, embryo and blastocyst cryopreservation in ART: systematic review and meta-analysis comparing slow-freezing versus vitrification to produce evidence for the development of global guidance

Preservation of female genetics is currently done primarily by means of oocyte and embryo cryopreservation. The field has seen much progress during its four-decade history, progress driven predominantly by research in humans, cows, and mice. Two basic cryopreservation techniques rule the field--controlled-rate freezing, the first to be developed, and vitrification, which, in recent years, has gained a foothold. While much progress has been achieved in human medicine, the cattle industry, and in laboratory animals, this is far from being the case for most other mammals and even less so for other vertebrates. The major strides and obstacles in human and other vertebrate oocyte and embryo cryopreservation will be reviewed here.

/pdf/current-progress-in-oocyte-and-embryo-cryopreservation-by-1vaq52igpf.pdf

Current progress in oocyte and embryo cryopreservation by slow freezing and vitrification

https://www.fertstert.org/article/S0015-0282(15)02037-3/pdf

Successful elective and medically indicated oocyte vitrification and warming for autologous in vitro fertilization, with predicted birth probabilities for fertility preservation according to number of cryopreserved oocytes and age at retrieval

https://www.fertstert.org/article/S0015-0282(12)02494-6/pdf

Trophectoderm grade predicts outcomes of single-blastocyst transfers.

The purpose of this study was to demonstrate the safety and efficacy of vitrification of human pronuclear stage (PN) embryos in the human assisted reproduction laboratory. Using single pronucleate (1PN) and three pronucleate (3PN) zygotes, the impact of vitrification in the Flexipet denuding pipette (FDP) as a carrier was assessed in terms of survival, embryonic development and blastocyst formation when compared according to the PN number, and unvitrified controls. A total of 65 1PN and 152 3PN zygotes were vitrified; after warming 82% (53/65) of 1PN and 90% (137/152) of 3PN survived. The overall percentage of warmed zygotes (1PN and 3PN) that cleaved and reached 2-cell stage did not differ (χ 2 ; P = 0.32) from the control groups (77%; 147/190 versus 85%; 115/136). In addition, when the cleavage behaviour was examined on day 3 for ≥4-cell stage, no significant differences (χ 2 ; P = 0.95) were observed between the vitrified group and the unvitrified control groups (74%; 109/147 versus 77%; 89/115). Comparing the developmental potential up to cavitation and blastocyst formation on day 5, the overall outcome of the vitrified PN was 31% compared with 33% for the controls (χ 2 ; P = 0.76). The simple vitrification protocol used in this study, and these data highlight the usefulness of vitrification using FDP as a consistent and effective cryopreservation method for pronuclear zygotes, and a suitable alternative to slow cryopreservation protocols.

Blastocyst development after vitrification of multipronuclear zygotes using the Flexipet denuding pipette.

https://www.fertstert.org/article/S0015-0282(08)03904-6/pdf

Elective single embryo transfer: A 6-year progressive implementation of 784 single blastocyst transfers and the influence of payment method on patient choice

// Bo Yu 1 , Valya R. Russanova 2 , Silvia Gravina 3 , Stephen Hartley 4 , James C. Mullikin 4, 5 , Alice Ignezweski 6 , James Graham 6 , James H. Segars 7 , Alan H. DeCherney 7 , Bruce H. Howard 2 1 Department of Obstetrics and Gynecology & Women's Health, Albert Einstein College of Medicine, Bronx, New York 10461, USA 2 Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute for Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA 3 Department of Genetics, Albert Einstein College of Medicine, Bronx, New York 10461, USA 4 Comparative Genomics Unit, Genome Technology Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892, USA 5 NIH Intramural Sequencing Center, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892, USA 6 Shady Grove Fertility Reproductive Science Center, Rockville, Maryland 20850, USA 7 Program in Reproductive and Adult Endocrinology, Eunice Kennedy Shriver National Institute for Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA Correspondence to: Bo Yu, e-mail: boyumich2@gmail.com Keywords: DNA methylation, transcription end site, fertility, ovarian granulosa cell, transcriptome Received: November 14, 2014      Accepted: December 08, 2014      Published: February 17, 2015 ABSTRACT Diminished ovarian function occurs early and is a primary cause for age-related decline in female fertility; however, its underlying mechanism remains unclear. This study investigated the roles that genome and epigenome structure play in age-related changes in gene expression and ovarian function, using human ovarian granulosa cells as an experimental system. DNA methylomes were compared between two groups of women with distinct age-related differences in ovarian functions, using both Methylated DNA Capture followed by Next Generation Sequencing (MethylCap-seq) and Reduced Representation Bisulfite Sequencing (RRBS); their transcriptomes were investigated using mRNA-seq. Significant, non-random changes in transcriptome and DNA methylome features are observed in human ovarian granulosa cells as women age and their ovarian functions deteriorate. The strongest correlations between methylation and the age-related changes in gene expression are not confined to the promoter region; rather, high densities of hypomethylated CpG-rich regions spanning the gene body are preferentially associated with gene down-regulation. This association is further enhanced where CpG regions are localized near the 3'-end of the gene. Such features characterize several genes crucial in age-related decline in ovarian function, most notably the AMH (Anti-Mullerian Hormone) gene. The genome-wide correlation between the density of hypomethylated intragenic and 3'-end regions and gene expression suggests previously unexplored mechanisms linking epigenome structure to age-related physiology and pathology.

/pdf/dna-methylome-and-transcriptome-sequencing-in-human-ovarian-4rdefh61f1.pdf

DNA methylome and transcriptome sequencing in human ovarian granulosa cells links age-related changes in gene expression to gene body methylation and 3'-end GC density.

J.R. Graham

Papers

Successful elective and medically indicated oocyte vitrification and warming for autologous in vitro fertilization, with predicted birth probabilities for fertility preservation according to number of cryopreserved oocytes and age at retrieval

Trophectoderm grade predicts outcomes of single-blastocyst transfers.

Blastocyst development after vitrification of multipronuclear zygotes using the Flexipet denuding pipette.

Elective single embryo transfer: A 6-year progressive implementation of 784 single blastocyst transfers and the influence of payment method on patient choice

DNA methylome and transcriptome sequencing in human ovarian granulosa cells links age-related changes in gene expression to gene body methylation and 3'-end GC density.