Kaori Goto

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.

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.

Decidualization modulates a signal transduction system via protease-activated receptor-1 in endometrial stromal cells

Decidual cells are thought to be involved in the maintenance of pregnancy. We conducted this study to evaluate the cellular function of endometrial stromal cells (ESCs) transitioning to decidualization.