Quality evaluation of IVM embryo and imprinting genes of IVM babies

DNA Methylation in Offspring Conceived after Assisted Reproductive Techniques: A Systematic Review and Meta-Analysis

Background: In the last 40 years, assisted reproductive techniques (ARTs) have emerged as potentially resolving procedures for couple infertility. This study aims to evaluate whether ART is associated with epigenetic dysregulation in the offspring. Methods. To accomplish this, we collected all available data on methylation patterns in offspring conceived after ART and in spontaneously conceived (SC) offspring. Results. We extracted 949 records. Of these, 50 were considered eligible; 12 were included in the quantitative synthesis. Methylation levels of H19 CCCTC-binding factor 3 (CTCF3) were significantly lower in the ART group compared to controls (SMD −0.81 (−1.53; −0.09), I² = 89%, p = 0.03). In contrast, H19 CCCTC-binding factor 6 (CTCF6), Potassium Voltage-Gated Channel Subfamily Q Member 1 (KCNQ1OT1), Paternally-expressed gene 3 (PEG3), and Small Nuclear Ribonucleoprotein Polypeptide N (SNRPN) were not differently methylated in ART vs. SC offspring. Conclusion: The methylation pattern of the offspring conceived after ART may be different compared to spontaneous conception. Due to the lack of studies and the heterogeneity of the data, further prospective and well-sized population studies are needed to evaluate the impact of ART on the epigenome of the offspring.

The feasibility of switching from IVF to IVM combined with all-blastocyst-culture and transfer for patients with ovarian hyperstimulation syndrome tendency

OBJECTIVE

To investigate the feasibility of switching from in vitro fertilization (IVF) to in vitro maturation (IVM) combined with all-blastocyst-culture and transfer as a supplementary infertility treatment in patients with ovarian hyperstimulation syndrome (OHSS) tendency METHODS: Retrospective cohort study including 184 patients who switched from IVF and underwent 192 IVM cycles between January 2016 and December 2020. The outcomes were compared between cleavage-stage embryo transfer (group A, n = 74) and blastocyst-stage transfer (group B, n = 52) groups.

RESULTS

The OHSS rate is 0%. 66 cycles were canceled for transfer. Among the 126 transfer cycles, number of retrieved oocytes, proportion of metaphase II oocytes, cleavage rate, and proportion of high-quality embryos on day 3 post-fertilization are significantly lower in group A than that in group B. On the contrary, number of transferred embryos is significantly lower in group B than that in group A, whereas the rates of implantation, clinical pregnancy, and live births are significantly higher in group B than that in group A.

CONCLUSION

Timely switching to IVM combined with all-blastocyst-culture and transfer for patients undergoing controlled ovarian hyperstimulation and exhibiting characteristics of OHSS tendency is feasible as a supplementary infertility treatment.

Maternal and neonatal outcome and children's development after medically assisted reproduction with in-vitro matured oocytes-a systematic review and meta-analysis

BACKGROUND

IVM was implemented in medically assisted reproduction 25 years ago. IVM does not involve controlled ovarian stimulation (COS) and is mainly indicated in patients with a high risk of ovarian hyperstimulation syndrome, in particular in patients with polycystic ovary syndrome (PCOS); it is also an acknowledged option in fertility protection. However, the in-vitro culture of immature oocytes raises concerns over their developmental potential and the putative impact on children's health. Although an increasing number of studies on obstetric and neonatal outcomes of IVM children and their development have been published in recent years, study designs are difficult to compare, since IVM is used in women with various indications and IVM protocols do not follow the same standards.

OBJECTIVE AND RATIONALE

The aim of this systematic review was to evaluate the current evidence from IVM children of an impact of in-vitro culture of immature oocytes. Primary outcome parameters were birthweight and children's development up to the age of 2 years. We also compared pregnancy pathologies and the outcome of IVM children and COS children in relation to maternal indications, in particular PCOS, and to the type of IVM protocols with or without ovulation trigger as the secondary outcome parameters. IVM is an accepted clinical option for many centres; however, a comprehensive analysis of the available data is needed to establish whether the use of human oocytes that are fully matured in vitro is safe for both children and their mothers.

SEARCH METHODS

Google Scholar and PubMed were used for identifying peer-reviewed original articles and reviews through January 2020. A total of 191 studies were screened and 16 studies were included in the qualitative synthesis. Studies were stratified according to indications, the use of an ovulation trigger and multiplicity.

OUTCOMES

Birthweights of IVM singletons and multiples were comparable to their respective COS controls: birthweights were also similar if the analysis was restricted to mothers with PCOS. IVM children had a comparable birthweight to COS children, irrespective of whether an ovulation trigger was used in IVM cycles or not. The frequency of gestational diabetes (GD) in singleton pregnancies was comparable between IVM and COS, regardless of infertility background. There was also no difference in GD frequency between IVM and COS, if an hCG ovulation trigger in IVM cycles was used or not. Hypertensive disorders in singleton pregnancies of women with PCOS were significantly more frequent after IVM compared to COS, in particular if IVM cycles were performed only with in-vitro matured oocytes. There was no difference in the preterm birth rate of singleton pregnancies between IVM and COS. Preterm birth rates were still similar if only women diagnosed with PCOS were compared and whether an ovulation trigger in IVM was used or not. The malformation rate in IVM children did not differ in COS children versus children after natural conception. At the age of 2 years, IVM singletons showed similar anthropometric and mental development compared to COS children or children from natural conception.

WIDER IMPLICATIONS

The higher incidence of hypertensive disorders in IVM pregnancies needs monitoring during pregnancy. Current data on the development of IVM children are encouraging, although the quality of many studies is limited and long-term data beyond 2 years are scarce. Further studies should be based on generally accepted IVM protocols. Studies on long-term outcomes beyond 2 years are needed to search for potential long-time sequelae of IVM.

Predicting The Developmental Potential Of Cleavage Stage Embryos Based On Oxygen Consumption Rate In FET Cycles

OBJECTIVE

To study the value of oxygen consumption (OC) as a predictor of the developmental potential of D3 embryos in frozen embryo transfer (FET) cycles.

METHODS

This observational study included 148 patients undergoing FET cycles with two embryos transferred per cycle. OC rates were examined by scanning electrochemical microscopy before embryo transfer. Implantation, clinical pregnancy, miscarriage, and live birth rates were calculated.

RESULTS

A total of 296 embryos were transferred in 148 cycles, or two embryos per cycle. The embryos were divided into three groups based on OC: Group A included the cases in which the OC rate of each of the two transferred embryos was greater than 3.0 fmol/s; Group B included the cases in which the OC rate of one of the embryos was greater than 3.0 fmol/s and the OC rate of the other embryo was less than 3.0 fmol/s; and Group C included the cases in which the OC rates of the two embryos were less than 3.0 fmol/s. Higher live birth rates and lower miscarriage rates were observed in Group A (p<0.05).

CONCLUSIONS

Our data suggest that OC is positively correlated with embryo developmental potential. Therefore, measuring the OC of human embryos may be useful in embryo assessment.

Vitrification of Human In-Vitro Matured Oocytes: Effects on Mitochondrial Ultrastructure and Oxygen Consumption

Background: This study was conducted to evaluate the impact of vitrification on mitochondrial of human IVM oocytes.

Methods: A total of 401 immature oocytes were obtained from ovarian stimulated cycles, which were randomly divided into fresh and vitrification groups after IVM. According to the cultured time after thawing, the vitrification groups were divided into 0 hours (0 h), 2 hours (2 h), or 4 hours (4 h) subgroups. Mitochondrial morphology and oxygen consumption were compared among the four groups. After fertilization by ICSI, normal fertilization, cleaved embryos, and blastocyst formation rate were also calculated.

Results: The mean gray value of mitochondria structure was significantly decreased in 0 h and 2 h groups when compared to control group (0.48 ± 0.09, 0.50 ± 0.36 vs. 0.61 ± 0.12, respectively; P [Formula: see text] 0.05), and recovered (0.61 ± 0.24 vs. 0.61 ± 0.12, P [Formula: see text] 0.05) in 4 h group. In addition, oxygen consumption was also significantly decreased in 0 h and 2 h groups compared to fresh (2.91 ± 0.77 fmol/s, 3.26 ± 1.34 fmol/s vs. 3.96 ± 1.44 fmol/s, respectively; P [Formula: see text] 0.05), and recovered after 4 h culture (3.96 ± 1.44 fmol/s vs. 4.41 ± 1.38 fmol/s, respectively; P [Formula: see text] 0.05). The percentage of normal fertilization and cleaved embryos were no differences among the four groups, however, blastocyst development rate was significantly lower in 0 h group.

Conclusion: These results indicate that during the vitrification process, the oxygen consumption and mitochondrial structure of oocytes may undergo temporary dynamic changes, but appear to recover by 4 hours.

Oocyte in vitro maturation: A sytematic review

In vitro maturation (IVM) is one of the most controversial aspects of assisted reproductive technology. Although it has been studied extensively, it is still not a conventional treatment option and is accepted as an alternative treatment. However, studies have shown that IVM can be used in almost all areas where in vitro fertilization (IVF) is used and it has a strong place in fertility protection and Ovarian Hyperstimulation syndrome management. The aim of this systematic review was to address all aspects of the current knowledge of IVM treatment together with the evolution of IVM and IVF.

Development of in vitro maturation techniques for clinical applications

In vitro maturation (IVM) refers to maturation in culture of immature oocytes at different stages that may or may not have been exposed to short courses of gonadotropins. The source of immature oocytes is an important feature for subsequent embryonic development, pregnancy, and healthy live births. IVM is an effective treatment that has already achieved significant outcomes of acceptable pregnancy and implantation rates and has led to the births of several thousand healthy babies. As the development of IVM treatment continues, an attractive possibility for improving the already successful outcome is to combine a natural-cycle in vitro fertilization (IVF) treatment with immature-oocyte retrieval followed by IVM of those immature oocytes. If the treatment processes can be simplified for immature-oocyte retrieval, different types of infertile women may be able to take advantage of these treatments. Mild-stimulation IVF combined with IVM treatment may represent a viable alternative to the standard treatment. Although IVM treatment is still considered to be experimental, it is now time to reconsider the IVM technology and its development. Mild-stimulation IVF combined with IVM may prove to be not just alternatives to standard treatments, but potentially first-line treatment choices.

Postnatal oogenesis in humans: a review of recent findings

In spite of generally accepted dogma that the total number of follicles and oocytes is established in human ovaries during the fetal period of life rather than forming de novo in adult ovaries, some new evidence in the field challenges this understanding. Several studies have shown that different populations of stem cells, such as germinal stem cells and small round stem cells with diameters of 2 to 4 μm, that resembled very small embryonic-like stem cells and expressed several genes related to primordial germ cells, pluripotency, and germinal lineage are present in adult human ovaries and originate in ovarian surface epithelium. These small stem cells were pushed into the germinal direction of development and formed primitive oocyte-like cells in vitro. Moreover, oocyte-like cells were also formed in vitro from embryonic stem cells and induced pluripotent stem cells. This indicates that postnatal oogenesis is not excluded. It is further supported by the occurrence of mesenchymal stem cells that can restore the function of sterilized ovaries and lead to the formation of new follicles and oocytes in animal models. Both oogenesis in vitro and transplantation of stem cell-derived "oocytes" into the ovarian niche to direct their natural maturation represent a big challenge for reproductive biomedicine in the treatment of female infertility in the future and needs to be explored and interpreted with caution, but it is still very important for clinical practice in the field of reproductive medicine.