Can Oocyte Diameter Predict Embryo Quality?

Bassil, Rawad; Casper, Robert F.; Meriano, Jim; Smith, R; Haas, Jigal; Mehta, Chaula; Orvieto, Raoul; Zilberberg, Eran

doi:10.1007/s43032-020-00306-3

Cited by 20 publications

(14 citation statements)

References 12 publications

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“…Indeed, we verified that the ZP was thicker in the naturally ovulated than in the superovulated oocytes. This is reminiscent of the variable ZP thickness reported in human oocytes after IVM, in which, in addition to the ZP, the oocyte proper (vitellus) was also found to vary in size 67,68 . Therefore, we checked whether the superovulated mouse oocytes with thinner or thicker ZP also presented different diameters, which proved to be the case.…”

Section: Discussionmentioning

confidence: 70%

The proteome, not the transcriptome, predicts that oocyte superovulation affects embryonic phenotypes in mice

Taher

Israel

Drexler

et al. 2021

Sci Rep

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Superovulation is the epitome for generating oocytes for molecular embryology in mice, and it is used to model medically assisted reproduction in humans. However, whether a superovulated oocyte is normal, is an open question. This study establishes for the first time that superovulation is associated with proteome changes that affect phenotypic traits in mice, whereas the transcriptome is far less predictive. The proteins that were differentially expressed in superovulated mouse oocytes and embryos compared to their naturally ovulated counterparts were enriched in ontology terms describing abnormal mammalian phenotypes: a thinner zona pellucida, a smaller oocyte diameter, increased frequency of cleavage arrest, and defective blastocyst formation, which could all be verified functionally. Moreover, our findings indicate that embryos with such abnormalities are negatively selected during preimplantation, and ascribe these abnormalities to incomplete ovarian maturation during the time of the conventional superovulation, since they could be corrected upon postponement of the ovulatory stimulus by 24 h. Our data place constraints on the common view that superovulated oocytes are suitable for drawing general conclusions about developmental processes, and underscore the importance of including the proteins in a modern molecular definition of oocyte quality.

show abstract

Section: Discussionmentioning

confidence: 70%

The proteome, not the transcriptome, predicts that oocyte superovulation affects embryonic phenotypes in mice

Taher

Israel

Drexler

et al. 2021

Sci Rep

View full text Add to dashboard Cite

show abstract

“…Indeed, we verified that the ZP was thicker in the naturally ovulated oocytes than in the superovulated oocytes. This is reminiscent of the variable ZP thickness reported in human oocytes after IVM, in which next to the ZP, also the oocyte proper (vitellus) was found to vary in size 68,69 . Therefore, we checked if the superovulated mouse oocytes with thinner or thicker ZP also presented different diameters, which was the case.…”

Section: Discussionmentioning

confidence: 64%

The Proteome, Not the Transcriptome, Predicts that Oocyte Superovulation Affects Embryonic Phenotypes in Mice

Taher

Israel

Drexler

et al. 2021

Preprint

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Superovulation is the epitome for generating oocytes for molecular embryology in mice, and it is used to model medically assisted reproduction in humans. Yet whether a superovulated oocyte is normal, is an open question. This study establishes for the first time that superovulation is associated with proteome changes that bear on phenotypic traits in mice, whereas the transcriptome is far less predictive. The proteins that were differentially expressed in superovulated mouse oocytes and their derived embryos relative to their naturally ovulated counterparts were enriched in ontology terms describing abnormal mammalian phenotypes: a thinner zona pellucida, a smaller oocyte diameter, increased cleavage arrest, and defective blastocyst formation, which we could all verify functionally. Moreover, our findings indicate that embryos with such abnormalities are negatively selected during preimplantation, and ascribe these abnormalities to incomplete ovarian maturation during the time of the conventional superovulation, since they could be corrected upon postponement of the ovulatory stimulus by 24 h. Our data place constraints on the common view that superovulated oocytes are suited to draw conclusions of general validity about developmental processes, and underscore the importance of including the proteins in a modern molecular definition of oocyte quality.

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“…In this study, oocyte diameter was significantly associated with the duration of the cytoplasmic halo. Previous studies have found that oocyte diameter depended on the degree of growth and maturity and correlated with the morphological grade of human blastocysts, in that very small oocytes resulted in decreased good-quality blastulation rates [ 29 , 30 ]. The halo is considered a marker of microtubule-organised translocation of cytoplasmic components to the centre of the oocyte [ 31 ].…”

Section: Discussionmentioning

confidence: 99%

Characteristics of the cytoplasmic halo during fertilisation correlate with the live birth rate after fresh cleaved embryo transfer on day 2 in minimal ovarian stimulation cycles: a retrospective observational study

Ezoe¹,

Miki²,

Okimura³

et al. 2021

Reprod Biol Endocrinol

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Background Information regarding the influence of cytoplasmic events during fertilisation on the clinical outcome remains limited. The cytoplasmic halo is one of these events. A previous study that used time-lapse technology found an association of the presence and morphokinetics of the cytoplasmic halo with cleavage patterns, development to the blastocyst stage, and the ongoing pregnancy rate after blastocyst transfer. Therefore, the cytoplasmic halo may be a useful predictor of the pregnancy outcome after cleaved embryo transfer. This study evaluated the ability of the cytoplasmic halo to predict a live birth after fresh cleaved embryo transfer on day 2, and sought to identify factors potentially influencing the presence and morphokinetics of the halo. Methods A total of 902 embryos cultured in the EmbryoScope+® time-lapse system and subjected to single fresh cleaved embryo transfer were retrospectively analysed. The presence and duration of a cytoplasmic halo were annotated. The initial positions of the pronuclei were also observed. The correlation between the cytoplasmic halo and live birth was evaluated and the association of the cytoplasmic halo with patient, cycle, and embryonic characteristics was determined. Results Absence of a cytoplasmic halo was associated with a significant decrease in the likelihood of a live birth after fresh cleaved embryo transfer. Prolongation of the halo, especially the duration of central repositioning of cytoplasmic granules, had an adverse impact on the live birth rate. The characteristics of the cytoplasmic halo were not affected by the ovarian stimulation method used, female age, the serum steroid hormone level on the day of trigger, or semen quality. However, the cytoplasmic halo was significantly affected by male age, oocyte diameter, and the initial position of the male pronucleus. Conclusions Absence or prolongation of the cytoplasmic halo was negatively correlated with the live birth rate after fresh cleaved embryo transfer. The characteristics of the cytoplasmic halo were strongly associated with oocyte diameter, male age, and the initial position of the male pronucleus. These findings indicate that the characteristics of the cytoplasmic halo can be used to select more competent embryos for transfer at the cleavage stage.

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Can Oocyte Diameter Predict Embryo Quality?

Cited by 20 publications

References 12 publications

The proteome, not the transcriptome, predicts that oocyte superovulation affects embryonic phenotypes in mice

The proteome, not the transcriptome, predicts that oocyte superovulation affects embryonic phenotypes in mice

The Proteome, Not the Transcriptome, Predicts that Oocyte Superovulation Affects Embryonic Phenotypes in Mice

Characteristics of the cytoplasmic halo during fertilisation correlate with the live birth rate after fresh cleaved embryo transfer on day 2 in minimal ovarian stimulation cycles: a retrospective observational study

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