PRONUCLEAR NUMERATION SHOULD NOT BE THE ONLY METHOD TO DETERMINE ABNORMAL FERTILIZATION IN ORDER TO ACCOUNT FOR ALL EUPLOID EMBRYOS

Hydatidiform moles are abnormal gestations characterised by the presence of hydropic changes in the placental villi associated with circumferential trophoblastic proliferation. They arise due to abnormal fertilization. Molar gestation commonly develops within the uterus but presence of molar changes in ectopic pregnancy is extremely rare. Author present a rare case of ectopic molar pregnancy in fallopian tube in a 20 years old female patient to highlight its clinicopathological features. Ectopic molar pregnancy in a fallopian tube is very rare and histopathological study is the gold standard for the exact diagnosis and further management.

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O-003 The puzzling unknowns of abnormal fertilization and first cleavage

Human Reproduction ◽

10.1093/humrep/deab125.025 ◽

2021 ◽

Vol 36 (Supplement_1) ◽

Author(s):

C Racowsky

Keyword(s):

Embryo Development ◽

Time Lapse ◽

Critical Event ◽

Cleavage Division ◽

Sequence Of Events ◽

Polar Bodies ◽

Abnormal Fertilization ◽

Temporal And Spatial ◽

Temporal Events ◽

Time Lapse Imaging

Abstract text Fertilization is a critical event in development in that it provides the connection between the gametes and the earliest stages of embryogenesis. Yet, despite the central importance of this process in contributing to embryo developmental fate, clinical embryologists have historically assessed fertilization merely by the number of pronuclei and, if two are present, perhaps, by the presence of two polar bodies. Even though over 20 years ago, time lapse imaging was applied for defining early events of fertilization (Payne et al., 1997), it is only with contemporary time-lapse imaging systems in the last few years that detailed evaluation of spatial and temporal events of fertilization have been described (Iwata & Yasuyuki, 2016; Cottichio et al., 2018). These careful analyses allow us to describe typical and atypical events of fertilization and how they are each associated with timing of the first cleavage division and subsequent embryo development. In this lecture, we will first describe the fundamental underpinnings of fertilization and highlight the normal events associated with this process. We will then discuss gross morphological abnormalities as visualized by light microscopy and highlight the unknowns associated with these events. Finally, we will focus on time-lapse imaging studies, which have revealed the remarkable spatial and temporal coordination of meiotic resumption, pronuclear dynamics, chromatin organization and cytoplasmic/cortical modifications that occur during fertilization and the implications of aberrations for the first cleavage division. At the conclusion of this presentation, attendees should be able to: Review the normal events associated with fertilization and the first cleavage division. 1 Describe gross morphological aberrations of these two fundamental processes. 2 Discuss temporal and spatial abnormalities in the coordinated sequence of events that underly these processes. 3 State the potential application of these abnormalities as predictors of abnormal embryo development. 4 Summarize the puzzling unknowns that underly these abnormalities.

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Exploration of the Cytoplasmic Function of Abnormally Fertilized Embryos via Novel Pronuclear-Stage Cytoplasmic Transfer

International Journal of Molecular Sciences ◽

10.3390/ijms22168765 ◽

2021 ◽

Vol 22 (16) ◽

pp. 8765

Author(s):

Ayako Fujimine-Sato ◽

Takashi Kuno ◽

Keiko Higashi ◽

Atsushi Sugawara ◽

Hiroaki Hiraga ◽

...

Keyword(s):

Step Method ◽

Developmental Potential ◽

Age Related ◽

Ivf Failure ◽

Abnormal Fertilization ◽

Epigenetic Events ◽

Potential Alternative ◽

The Difference ◽

Pn Stage ◽

Cytoplasmic Transfer

In regular IVF, a portion of oocytes exhibit abnormal numbers of pronuclei (PN) that is considered as abnormal fertilization, and they are routinely discarded. However, it is known that abnormal ploidy still does not completely abandon embryo development and implantation. To explore the potential of cytoplasm from those abnormally fertilized oocytes, we developed a novel technique for the transfer of large cytoplasm between pronuclear-stage mouse embryos, and assessed its impact. A large volume of cytoplast could be efficiently transferred in the PN stage using a novel two-step method of pronuclear-stage cytoplasmic transfer (PNCT). PNCT revealed the difference in the cytoplasmic function among abnormally fertilized embryos where the cytoplasm of 3PN was developmentally more competent than 1PN, and the supplementing of fresh 3PN cytoplasm restored the impaired developmental potential of postovulatory “aged” oocytes. PNCT-derived embryos harbored significantly higher mitochondrial DNA copies, ATP content, oxygen consumption rate, and total cells. The difference in cytoplasmic function between 3PN and 1PN mouse oocytes probably attributed to the proper activation via sperm and may impact subsequent epigenetic events. These results imply that PNCT may serve as a potential alternative treatment to whole egg donation for patients with age-related recurrent IVF failure.

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142 POSSIBLE BENEFIT OF INTRACYTOPLASMIC SPERM INJECTION ON THE EFFICIENCY OF EMBRYO PRODUCTION IN AGED COWS

Reproduction Fertility and Development ◽

10.1071/rdv29n1ab142 ◽

2017 ◽

Vol 29 (1) ◽

pp. 179

Author(s):

F. Magata ◽

K. Tsuchiya ◽

H. Komaki ◽

M. Konishi ◽

A. Ideta

Keyword(s):

Intracytoplasmic Sperm Injection ◽

Blastocyst Stage ◽

Cortical Granule ◽

Cortical Granules ◽

Embryo Production ◽

Fertilization Rates ◽

Abnormal Fertilization ◽

Cytoplasmic Maturation ◽

Maternal Aging ◽

Bovine Oocytes

Reduction in oocyte quality is a major factor responsible for declining fertility with age. The abnormal fertilization rate of oocytes from aged cows was reportedly higher than that of oocytes from young cows (Iwata et al. 2011. Reprod. Fertil. Dev. 23, 424–432). We hypothesised that assisted fertilization by intracytoplasmic sperm injection (ICSI) might improve the developmental abilities of oocytes collected from aged females. The aims of the study were (1) to determine the effect of maternal aging on the ability of bovine oocytes to undergo cytoplasmic maturation, fertilization, and further embryo development; and (2) to determine whether ICSI would improve the efficiency of embryo production in aged cows. Cows aged 30 to 50 months or >120 months were defined as young or aged, respectively. Cumulus-oocyte complexes were harvested from abattoir-derived ovaries of young (40 ± 7 months, n = 89) and aged (136 ± 12 months, n = 55) Holstein cows and matured for 23 h in TCM-199 supplemented with 5% fetal bovine serum (FBS) at 38.5°C under 5% CO2 with saturated humidity. Then, surrounding cumulus cells were removed, and cortical granules in the oocyte were stained with Lens culinaris–fluorescein isothiocyanate to evaluate the cytoplasmic maturation. Matured oocytes were inseminated by IVF or ICSI. At 15 h post-insemination, the numbers of pronuclei were determined to evaluate the fertilization rates. Presumptive IVF- or ICSI-derived zygotes were cultured for 5 days in CR1aa medium with 2% FBS and subsequently in USU6 with 5% FBS for 3 days at 38.5°C in 5% O2, 5% CO2, and 90% N2 with saturated humidity. Chromosome numbers of blastocysts were counted to evaluate the effect of maternal aging on ploidy. All experiments were performed with more than 4 independent runs, and data were analysed using chi-square tests. The distribution of matured oocytes into different cortical granule classes was affected by age, with a significantly lower (P < 0.01) proportion of class III (mature cytoplasm) oocytes from aged cows (29%) compared with those from young cows (57%). Although fertilization rates following IVF did not differ between the groups, the proportion of abnormal fertilization (more than 2 pronuclei) was 32% in the aged group: higher than in the young group (15%; P < 0.01). The rates of cleaved embryos following IVF were the same among groups, but the rate of development to the blastocyst stage of oocytes from aged cows (38%) was significantly (P < 0.05) lower than in those from young cows (52%). Moreover, the proportion of diploid blastocysts with 2 sets of chromosomes (2n = 60) was lower (47%) in the aged than in the young groups (75%; P < 0.05). However, in the ICSI embryos, the rates of development to the blastocyst stage did not differ significantly between groups (young 36%; aged 43%). Thus, maternal aging might impair the cytoplasmic maturation of bovine oocytes, which could be associated with abnormal fertilization or low developmental competence. Our results also indicate possible beneficial effects of ICSI on the efficiency of embryo production in aged cows.

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