Piezo-ICSI for Human Oocytes

Since the first successful pregnancies achieved by intracytoplasmic sperm injection (ICSI) were reported, ICSI has become an essential technique in ...

Kameda Medical Center

Kameda IVF Clinic Makuhari

Tokyo Medical and Dental University

The epigenetic status of the genome changes dynamically from fertilization to implantation. In addition, the physiological environment during the process of gametogenesis, including parental age, may affect the epigenome of the embryo after fertilization. It is important to clarify the influence of parental age on gene expression in the embryo in terms of transgenerational epigenetics to improve the techniques currently used in assisted reproductive medicine. Here, we performed single-embryo RNA-seq analysis on human blastocysts fertilized by intracytoplasmic sperm injection, including from relatively elderly mothers, to elucidate the effects of parental age on the embryonic gene expression profile. We identified a number of genes in which the expression levels were decreased with increasing maternal age. Among these genes, several are considered to be important for meiotic chromosomal segregation, such as PTTG1, AURKC, SMC1B and MEIKIN. Furthermore, the expression levels of certain genes critical for autophagy and embryonic growth, specifically GABARAPL1 and GABARAPL3, were negatively correlated with advanced paternal age. In addition, levels of transcripts derived from major satellite repeats also decreased as the maternal age increased. These results suggest that epigenetic modifications of the oocyte genome may change with parental age and be transmitted to the next generation.

Parental age and gene expression profiles in individual human blastocysts.

The objective of this study was to investigate the effect of the head-first or tail-first injection of sperm into the cytoplasm by Piezo-ICSI (PICSI) on oocyte survival, fertilization, embryo development and implantation ability in humans.

Effects of sperm direction in Piezo-ICSI on oocyte survival, fertilization, embryo development and implantation ability in humans: A preliminary study.

Fertility preservation is an important issue for young cancer patients. Random-start controlled ovarian stimulation and double ovarian stimulation have been proposed for efficient oocyte retrieval within the limited time before cancer therapy. We aimed to clarify the efficacy of these new protocols within the Japanese population.

Random-start ovarian stimulation with aromatase inhibitor for fertility preservation in women with Japanese breast cancer.

A husband and his wife, both 34 years old, consulted our clinic because of primary infertility. Sperm analysis revealed that the sperm concentration, motility, and progressive motility were (42.8±22.8)×10/mL, 23.3%±12.2%, and 12.9%±6.1%, respectively. Based on Krugar strict morphology criteria, 100% of the sperm were teratozoospermic, with 7.9% DNA fragmentation index. Observation of the sperm under a transmission electron microscope revealed that most parts of the fibrous sheath (FS) surrounding the tails of the sperm were missing from midway through the principal piece to the end piece, although the sperm's heads, necks and midpieces were morphologically normal. To collect oocytes, the gonadotropin-releasing hormone antagonist protocol was carried out, and 7 oocytes were retrieved. Intracytoplasmic sperm injection (ICSI) was performed for all the teratozoospermic sperm. Of the 7 oocytes, 3 were fertilized, and one 8-cell embryo and 2 expanded blastocysts were vitrified. Although repeated transfers of expanded blastocysts resulted in no implantation, one 8-cell embryo transfer in a hormone replacement therapy cycle led to pregnancy. The pregnancy using an 8-cell vitrified embryo resulted in the delivery of a healthy female baby at 38 weeks of gestation. No congenital malformations were found until 28 days after birth. Our results demonstrated that healthy birth could be achieved following the transfer of an embryo derived from ICSI using teratozoospermic sperm exhibiting the dysplasia of the fibrous sheath (DFS). Furthermore, while the previous reports on DFS have not investigated male infertility, we evaluated sperms from various aspects such as Kruger sperm function test, chromatin dispersion test, electron microscopy findings, time-lapse images of the obtained embryos, and concluded that ICSI could be desirable as a treatment policy for DFS.

Successful pregnancy and delivery achieved following intracytoplasmic sperm injection using teratozoospermic sperm exhibiting marked dysplasia of the fibrous sheath: a case report.

Article	Year
Parental age and gene expression profiles in individual human blastocysts. Scientific reports\| PubMed ID: 29402920	2018
Effects of sperm direction in Piezo-ICSI on oocyte survival, fertilization, embryo development and implantation ability in humans: A preliminary study. The journal of obstetrics and gynaecology research\| PubMed ID: 29992667	2018
Random-start ovarian stimulation with aromatase inhibitor for fertility preservation in women with Japanese breast cancer. Reproductive medicine and biology\| PubMed ID: 30996680	2019
Successful pregnancy and delivery achieved following intracytoplasmic sperm injection using teratozoospermic sperm exhibiting marked dysplasia of the fibrous sheath: a case report. Translational andrology and urology\| PubMed ID: 32420187	2020

Kiyotaka Kawai

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