Yoko Kumasako

The efficacy of the transfer of twice frozen-thawed embryos with the vitrification method

OBJECTIVE To confirm the clinical benefits of recryopreserved, twice-thawed embryo transfer (ET). DESIGN Retrospective study. SETTING Private fertility clinic. PATIENT(S) Forty-nine women whose embryos had been refrozen after a previous frozen-thawed ET. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Comparison of implantation and pregnancy rates of twice-cryopreserved, twice-thawed embryos versus once-cryopreserved, once-thawed embryos. RESULT(S) The pregnancy rate per ET cycle was 27.8% in the refrozen group and 25.9% in the control group (no statistically significant difference). The implantation rate was 25.0% in the refrozen group and 19.3% in the control group (no statistically significant difference). CONCLUSION(S) The refreezing of supernumerary embryos can prevent ovarian hyperstimulation syndrome in stimulated patients and in those who have experienced repeated failed pregnancies. If unexpected supernumerary embryos are available for recryopreservation after frozen-thawed ET, these embryos may be revitrified for a future transfer.

Evaluating the Quality of Human Embryos with a Measurement of Oxygen Consumption by Scanning Electrochemical Microscopy

ABSTRACT Morphological evaluation has been widely used to evaluate embryo quality because it is non-invasive and useful in predicting pregnancy rate. However, morphological evaluations are subjective and categorization standards often vary between investigators. The respiration rate of embryos is a useful parameter for evaluating embryo quality. The scanning electrochemical microscopy (SECM) measuring system provides a non-invasive, simple, accurate, and consistent measurement of the respiration activity of human embryos. After morphological evaluation by Veecks method, oxygen consumption by individual human embryos was quantified by SECM. Fundamentally, the maturation of mitochondria correlated with an increase in oxygen consumption during the development of embryos. The development of mitochondria may be an important factor in embryo quality, because mitochondria provide ATP for embryonic development by metabolism of nutrients in the cytoplasm. The respiration rates on the day 3 after in vitro fertilization (IVF) were measured and significant differences in oxygen consumption were registered even among embryos with the same morphological classification. There were no significant differences between the mean rates of oxygen consumption at each cleavage stage, however, there was considerable variation in respiration rate within embryos of the same morphological grade. The safety of SECM is assured as the embryos which were examined by SECM for oxygen consumption showed the same development levels as the control group. These results support the hypothesis that measuring embryonic respiration provides additional and valuable information about embryo quality.

Successful Pregnancy After the Vitrification of Zygotes Using Commercial Vitrification Solutions and Conventional Straws to Protect Against Infections in Liquid Nitrogen

Purpose: To report on successful birth after the transfer of postthawed human zygotes that were vitrified using a conventional straw for the purpose of protecting them from infections and a low-toxicity cryoprotectant that is commercially sold.Methods: A primary infertile couple presented at our IVF program. After being checked for fertilization, the embryos were not transferred to the uterus at that cycle. Instead, all of them were cryopreserved at the 2-pronuclei stage using our original vitrification method. After the vitrification and warming of four zygotes, two embryos were transferred into the uterus.Results: Twenty-one 2-pronuclei embryos were vitrified in liquid nitrogen. After 2 embryos were thawed and transferred, successful pregnancy was the outcome, and a healthy boy was born at term.Conclusions: Vitrification is a simple procedure and requires less time than slow freezing. Vitrification of zygotes in a conventional straw seems to be sufficient for viability and works to store the zygotes safely.

Respiratory Activity of Single Blastocysts Measured by Scanning Electrochemical Microscopy : the Relationship between Pre-freezing and Post-warming

Abstract: The aim of this retrospective study was to investigate the relationship between the oxygen consumption rate of blastocysts before freezing and their viability after warming with respect to their re-expansion and blastomere loss after warming. A total of 41 blastocysts from 29 in vitro fertilization (IVF) treatment cycles, that were not scheduled for cryopreservation for the next cycle, were examined. Good quality blastocysts were defined those having as less than 20% of blastomere loss, and rapid re-expanded blastocysts were defined those having as more than 50% blastocoel re-expansion during post-warming culture of 2 h. We evaluated the oxygen consumption rates before freezing and after warming as well as their relationship with the morphological features of good-quality and rapid re-expanded blastocysts during the post-warming culture. Good-quality blastocysts had a significantly higher oxygen consumption rate after warming than damaged blastocysts; furthermore, rapid re-expanded blastocysts had a significantly higher oxygen consumption rate before freezing than slow or no re-expansion blastocysts. These observations suggest that measurements of the oxygen consumption rate of individual blastocysts before freezing provides important information regarding viability after warming from the viewpoint of blastocoel re-expansion.

Effects of cyclophosphamide administration on the in vitro fertilization of mice

To evaluate the oocyte fertilization ability and embryo growth after cyclophosphamide (CPA) treatment in mice.

Prediction of the in vitro developmental competence of early-cleavage-stage human embryos with time-lapse imaging and oxygen consumption rate measurement

To assess an embryos ability to develop into a good‐quality blastocyst during the early‐cleavage stage using time‐lapse imaging and the oxygen consumption rate.

The new embryo culture medium based on the amino acid concentration of human oviductal fluid enhance the embryo developmental ability; randomized trial

ried for 5 days before she returned to have embryo development evaluated and an embryo transfer. IUI’s were performed with gradient prepared semen per standard protocols. Data was collected for a single calendar year in 2017. RESULTS: A total of 36 patients, between ages 27 and 42, opted to have IVC cycles performed. All patients were able to tolerate the device well, with no adverse events requiring premature removal of the device. The per-start positive biochemical pregnancy rate was 52% and the ultrasound confirmed pregnancy rate was 47%. The per-transfer pregnancy rates were 69% and 63% respectively with a total of 28 transfers performed (a 22% non-transfer rate). The pregnancy rates for IUI performed in the same calendar year were 13% and 12% respectively for patients in the same age bracket with a total of 869 cycles performed. CONCLUSIONS: IVC with day 5 blastocyst transfers appears to offer an appreciable pregnancy rate increase when compared with IUI cycles. While IVC cannot compete with full IVF cycles, due to inherent treatment limitations, it may offer a more efficacious first treatment option for infertility patients that meet the selection criteria than several rounds of IUIs. However, despite success for a large percentage of patients, we observed a high non-transfer rate of 22% due to either no fertilization or poor embryo progression. Although disappointing, these patients can now progress to full IVF cycles sooner than if they had continued with IUI cycles as IVC cycles offer more diagnostic value than IUIs. More research is needed to understand if IVC can effectively, in terms of cost and patient success, be added to most center’s treatment repertoires and become an additional standard of care.

The Relationship between the Level of Progesterone Secreted from Cumulus Cells and Oocyte Developmental Competence in In Vitro Matured Human Cumulus Oocyte Complexes

Abstract: Developmental competence of in vitro matured human oocytes is dependent on the morphology of the cumulus-oocyte complex (COC) just after collection from the follicle. We postulated that COCs categorized as having poor morphology (two or fewer less than two layers of cumulus cells) would not secrete a sufficient amount of matulation factors, resulting in low developmental competence of the matured oocytes. In the present study, the level of progesterone secreted from good morphology COCs with three or more layers of cumulus cells, 39.2 ± 12.8 ng/ml (n=31), was significantly higher than that secreted from poor morphology COCs (9.65 ± 1.34 ng/ml, n=22). The addition of 20 ng/ml progesterone to in vitro maturation culture of the poor morphology group significantly improved the fertilization ability of the oocytes. The rates of development to the morula and blastosyst stages were also increased by progesterone, however the differences were not significant. In conclusion, the secreted level of progesterone during in vitro maturation of human COCs was dependent on the number of cumulus cells attached to oocyte. When an oocyte is surrounded by two or fewer 2 layers of cumulus cells, the addition of progesterone to FSH- and hCG-containing medium appears to be a useful method for obtaining an oocyte with a high developmental competence.