Effect of culture environment on embryo quality and gene expression – experience from animal studies

Lonergan, Patrick; Rizos, Dimitrios; Gutiérrez-Adán, A.; Fair, Trudee; Boland, M.P.

doi:10.1016/s1472-6483(10)62088-3

Cited by 122 publications

(76 citation statements)

References 86 publications

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“…At the end of G1, cells are committed to division and lose the ability to respond to external factors. The nonacquisition of cytoplasmic competence during oocyte maturation may result in a longer G2 phase, which will result in a greater sensitivity to external factors and may explain the intense embryo blockage that occurs in this embryonic stage (Biase et al, 2009;Lonergan et al, 2003). Unlike the IVF 8-16C embryos, all the transcripts were downregulated in the PA group, suggesting a failure in the mechanism of EGA, at least in relation to the events related to cell cycle.…”

Section: Discussionmentioning

confidence: 98%

The Mechanism of Oocyte Activation Influences the Cell Cycle–Related Genes Expression During Bovine Preimplantation Development

Milazzotto

Feitosa

Paula-Lopes

et al. 2012

Cellular Reprogramming

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The first cleavage divisions and preimplantation embryonic development are supported by mRNA and proteins synthesized and stored during oogenesis. Thus, mRNA molecules of maternal origin decrease and embryonic development becomes gradually dependent on expression of genetic information derived from the embryonic genome. However, it is still unclear what the role of the sperm cell is during this phase and whether the absence of the sperm cell during the artificial oocyte activation affects subsequent embryonic development. The objective of this study was to determine, in bovine embryos, changes in cell cycle-associated transcript levels (cyclin A, cyclin B, cyclin E, CDC2, CDK2, and CDK4) after oocyte activation in the presence or absence of the sperm cell. To evaluate that, in vitro-produced (IVP) and parthenogenetically activated (PA) embryos (2-4 cells (2-4C), 8-16 cells (8-16C) and blastocysts) were evaluated by real-time PCR. There was no difference in cleavage and blastocyst rates between IVP and PA groups. Transcript level was higher in oocytes than in IVP and PA embryos. Cleaved PA embryos showed higher expression of cyclin A, cyclin B, cyclin E, and CDK2 and lower expression of CDC2 when compared with that from the IVP group. At the time of activation, all transcripts were expressed less in PA than in IVP embryos, whereas at the blastocyst stage, almost all genes were expressed at a higher level in the PA group. These results suggest that in both groups there is an initial consumption of these transcripts in the early stages of embryonic development. Furthermore, 8-16C embryos seem to synthesize more cell cycle-related genes than 2-4C embryos. However, in PA embryos, activation of the cell cycle genes seems to occur after the 8-to 16-cell stage, suggesting a failure in the activation process.

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Section: Discussionmentioning

confidence: 98%

The Mechanism of Oocyte Activation Influences the Cell Cycle–Related Genes Expression During Bovine Preimplantation Development

Milazzotto

Feitosa

Paula-Lopes

et al. 2012

Cellular Reprogramming

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“…For instance, mouse embryos cultured under suboptimal conditions demonstrated differences in birthweight (Banrezes et al, 2011), imprinting (Fernandez-Gonzalez et al, 2004Rivera et al, 2008) and gene expression (Ecker et al, 2004;Rinaudo and Schultz 2004;Giritharan et al, 2007). Errors in imprinting in domestic animals have been linked to culture conditions as well (Lonergan et al, 2003). Adverse effects of in vitro culture may also affect human development, with evidence that shorter culture times yield better longterm outcomes (Kallen et al, 2010;Kalra et al, 2012) and that culture media composition can affect birthweights (Dumoulin et al, 2010;Nelissen et al, 2012).…”

Section: Discussionmentioning

confidence: 99%

Advances in quality control: mouse embryo morphokinetics are sensitive markers of in vitro stress

Wolff

Fredrickson

Walker

et al. 2012

Fertility and Sterility

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what is known already: Current quality control testing methodology is sensitive but further improvements are needed to assure optimal culture conditions. MKs of embryo development may detect small variations in culture conditions. study design: Cross sectional-control versus treatment. Mouse embryo development kinetics of 466 embryos were analyzed according to exposure to various concentrations of toxins and toxic mineral oil. materials, setting, methods: Cryopreserved 1-cell embryos from F1 hybrid mice were cultured with cumene hydroperoxide (CH) (0, 2, 4, 6 and 8 mM) and Triton X-100 (TX-100; 0, 0.0008, 0.0012, 0.0016 and 0.002%). Using the Embryoscope, time-lapse images were obtained every 20 min for 120 h in seven focal planes. End-points were timing and pattern of cell division and embryo development. The blastocyst rate (BR) was defined as the percentage of embryos that developed to the expanded blastocyst stage within 96 h. main results and the role of chance: BR was not affected for embryos cultured in the three lowest concentrations of CH and the four lowest concentrations of TX-100. In contrast, a unique MK model detected all concentrations tested (P , 0.05). The MK model identified toxicity in two lots of toxic mineral oil that did not affect BR (P , 0.05).limitations, reasons for caution: A limited number of toxins were used so that the results may not apply to all potential embryo toxins. A larger sample size may also demonstrate other statistically significant developmental kinetic parameters.wider implications of the findings: MKs in mouse embryos are a sensitive and efficient method for quality control testing of in vitro culture conditions. BR, the end-point of traditional quality control assays, did not detect sublethal concentrations of toxins in the culture milieu in our study. This study demonstrates that temporal variation at key developmental stages reflects the quality of the culture environment. An MEA that incorporates MK will provide enhanced sensitivity and faster turn-around times.

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“…However, some authors argue that blastocyst culture might negatively affect the quality of embryo. Experiences from animal studies have shown that post-fertilization culture environment had a profound effect on the relative abundance of gene transcripts within the embryo and culture under suboptimal conditions could lead to perturbations in the pattern of expression [31,32]. This question remains a matter of debate.…”

Section: Discussionmentioning

confidence: 99%

Top quality embryos at day 2: a prerequisite for single blastocyst transfer? An observational cohort study in women under 36

Guérif

Lemseffer

Blanchard

et al. 2009

J Assist Reprod Genet

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Purpose While extended culture has been considerably improved, some questions remain regarding the application of Single Blastocyst Transfer (SBT). Methods An observational cohort study was undertaken with 456 women under 36 years old and assigned to SBT on a voluntary basis. The main outcome was the cumulative delivery rate per couple according to the number of Top Quality Embryos (TQE) on day 2 (Group 1= ≥2 TQE, Group 2= 1 TQE and Group 3= 0 TQE). Results Rate of transfer and mean number of frozen blastocyts were higher in Group 1 compared to Group 3. As a consequence, the cumulative delivery rate per couple was higher in Group 1 (47.9%) compared to Group 3 (34.9%). Conclusions Single blastocyst transfer combining fresh and frozen cycles, might be a worthwhile strategy irrespective of embryo quality on day 2 providing good delivery rates while keeping the rate of multiple deliveries low.

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Effect of culture environment on embryo quality and gene expression – experience from animal studies

Cited by 122 publications

References 86 publications

The Mechanism of Oocyte Activation Influences the Cell Cycle–Related Genes Expression During Bovine Preimplantation Development

The Mechanism of Oocyte Activation Influences the Cell Cycle–Related Genes Expression During Bovine Preimplantation Development

Advances in quality control: mouse embryo morphokinetics are sensitive markers of in vitro stress

Top quality embryos at day 2: a prerequisite for single blastocyst transfer? An observational cohort study in women under 36

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