Developmental competence of in vitro-matured human oocytes obtained from pregnant and non-pregnant women

IVM of human immature oocytes for infertility treatment and fertility preservation

Background

Thousands of healthy babies are born from in vitro maturation (IVM) procedures, but the rate of efficiency differs with the source of immature oocytes obtained. Recently, there are different IVM protocols proposed for infertility treatment and fertility preservation.

Methods

Based on the literature, the clinical application for IVM of immature oocytes was summarized.

Main findings Results

Immature oocytes may be retrieved from women after priming with or without the use of follicular stimulation hormone (FSH), human chorionic gonadotrophin (hCG) or a combination of both FSH and hCG. Successful pregnancy rates with IVM technology seem to be correlated with the number of immature oocytes obtained. With the source and culture course of immature oocytes, there are various IVM protocols. IVM of immature oocytes is profoundly affected by the culture conditions, but no breakthrough has been made by improving the IVM medium itself. Thus, the clinical application of IVM technology continues to evolve.

Conclusion

IVM technology is a useful technique for infertile women and fertility preservation. Mild stimulation IVF combined with IVM of immature oocytes is a viable alternative to the conventional stimulation IVF cycle treatment as it may prove to be an optimal first-line treatment approach.

In vitro embryo production from ewes at different physiological stages

BACKGROUND

The collection of ovaries from slaughterhouses is an important source of oocytes for in vitro embryo production. On the other hand, the physiological stage of slaughtered females varies and influences embryo production.

OBJECTIVES

The study examined the in vitro efficiency of embryos and demi-embryos from young, non-pregnant adult, and pregnant adult ewes from a local slaughterhouse.

METHODS

One thousand three hundred ovaries were collected from August to October 2020. The recovered oocytes were matured, fertilized, and cultured at 5% CO₂, 38.5°C, and 100% humidity. Embryo bisection was performed in 96 blastocysts (n = 32 per treatment). The demi-embryo pairs were incubated for their reconstitution for 12 h. SAS was used for data analysis.

RESULTS

The number of oocytes collected from the experimental group of non-pregnant adult ewes was higher (p ≤ 0.007) than those collected from the group of pregnant adult ewes (2.67 ± 0.19 vs. 2.18 ± 0.15 oocytes/group, respectively). The blastocyst rate was higher (p ≤ 0.0001) in the non-pregnant adult group (36.39%) than in the young (17.96%). The ratio of demi-embryos that recovered the blastocoelic cavity was higher (p < 0.05) in the young group (81.25%) than in the pregnant adult group (59.38%). The diameter of the demi-embryos was higher (p < 0.05) in the non-pregnant adult group (186.54 ± 8.70 μm) than those in the young and pregnant adult groups.

CONCLUSIONS

In conclusion, the in vitro embryo production efficiency was highest when using oocytes from non-pregnant adult ewes under the conditions of this study.

Effect of dominant follicle status at the time of retrieval on the clinical outcomes in natural cycle IVF combined with immature oocyte treatment

Objective: It is commonly believed that the oocytes from small follicles are unhealthy when a dominant follicle (DF) is recruited in the ovaries, especially when the DF is ovulated. This study aims to confirm whether the presence or ovulation of DF at the time of retrieval affects the clinical outcome of the natural cycle IVF with in vitro maturation (NC-IVF/M) treatment.

Methods: Data were collected from 446 women with regular menstrual cycle and 536 retrieval cycles using NC-IVF/M treatment. The cycles were divided into three groups based on the results of the oocyte retrieval cycle. Group A covers the collection of oocytes from the DF and small follicles; Group B incorporates failed oocyte retrieval from DF and then the oocytes are retrieved only from small follicles; and Group C includes the retrieval of oocytes only from small follicles accompanied with an ovulated DF. Furthermore, Group B and C have subgroups to include whether in vivo matured oocytes were obtained from small follicles. Following aspiration of DF and small follicles, mature oocytes were inseminated on the date of retrieval by intracytoplasmic sperm injection (ICSI) and the immature oocytes were matured in vitro. If the immature oocytes were matured in vitro, they were inseminated using ICSI, and then the embryos obtained from in vivo and in vitro matured oocytes were transferred accordingly.

Results: The oocytes from DF were successfully retrieved in 445 cycles (83.0%), failed to be retrieved in 54 cycles (10.1%) and ovulated in 37 cycles (6.9%). In Group A, an average of 2.0 ± 1.7 mature oocytes were retrieved, which was significantly higher than the average of Group B, with 1.3 ± 1.3 matured oocytes and Group C, with an average of 1.1 ± 1.5 matured oocytes (P < 0.01). However, the average number of immature oocytes retrieved from each group show no difference among the three groups. There was no significant difference in maturation rates of immature oocytes, fertilization rates among the three groups. The clinical pregnancy rate per transfer cycle is 34.5%, 34.6% and 25.7% in Group A, B and C, respectively. No significant differences were observed in embryonic development and implantation capacity in Group B and C in comparison to Group A. And there was no significant difference in clinical pregnancy, implantation, live birth and miscarriage rates among the three groups. No significant differences were observed in the developmental and implantation capacity according to with or without in vivo matured oocytes were retrieved in Group B and Group C.

Conclusion: The presence or ovulation of the dominant follicle from the ovaries does not significantly influence the developmental and implantation capacity of immature oocytes retrieved from small follicles, suggesting that NC-IVF/M is a promising treatment option for women without ovarian stimulation.

The effect of lysophosphatidic acid-supplemented culture medium on human immature oocytes matured in vitro

BACKGROUND

Lysophosphatidic acid-supplemented culture medium significantly increases the oocyte maturation rate in vitro. However, potential targets and pathways involved remain unknown.

METHODS

A total of 43 women, who underwent cesarean section and aged between 18 and 35 years with good health, were included in this study. Immature oocytes were obtained and cultured with 10 µM lysophosphatidic acid. After culture, oocyte maturation was assessed and oocytes and cumulus cells were collected for RNA sequencing. Hierarchical indexing for spliced alignment of transcripts 2 method was used to align clean reads to the human genome. The featureCounts and edgeR package were used to calculate gene expression and analyze differences between groups respectively. ClusterProfiler program was used to perform Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis.

RESULTS

Oocyte maturation rate increased significantly following 48 h culture with lysophosphatidic acid. In cumulus cells, Gene Ontology analysis revealed the top 20 items enriched by upregulated genes and downregulated genes respectively; Kyoto Encyclopedia of Genes and Genomes analysis showed that upregulated genes in the treatment group were enriched in TNF signaling and insulin secretion pathways and downregulated genes were enriched in TNF signaling and cell adhesion molecules. In oocytes, Gene Ontology analysis revealed the top 20 items enriched by upregulated genes and downregulated genes respectively; Kyoto Encyclopedia of Genes and Genomes analysis showed that upregulated genes in the treatment group were enriched in MAPK signaling, gap junction, and cell cycle pathways and downregulated genes were enriched in MAPK signaling, estrogen signaling, RAP1 signaling, and gap junction pathways.

CONCLUSIONS

Lysophosphatidic acid in culture medium enhances human oocyte maturation in vitro and the identified some potential pathways may associate with oocyte maturation.