Oocyte cryopreservation would amount to a major breakthrough in reproductive medicine. Diverse strategies have been tested to minimise cooling-induced cell injury. Nevertheless, oocytes from various species have shown a particular sensitivity to freezing, due to their unique biological characteristics. Storage of human mature oocytes with slow freezing has resulted in low survival rates, although recent studies based on modified methods have reported higher success. Survival after thawing is not necessarily a guarantee of unaltered viability. Developmental failure at pre- or postimplantation stages may originate from critical perturbations of various cell components, such as the chromosome segregation apparatus, the intracellular calcium signalling system, and the cytoskeleton. Germinal vesicle (GV)-stage oocytes have been suggested to be more amenable to freezing. But their use would require efficient in vitro maturation systems, which are not presently available. Oocyte cryopreservation remains a realistic objective, provided that more systematic approaches are applied, such as thorough analysis of the plasmalemma permeability to water and the diverse cryoprotectants.
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http://dx.doi.org/10.1016/j.ejogrb.2004.01.006 | DOI Listing |
Vet Sci
January 2025
College of Animal Science and Technology, Shihezi University, Shihezi 832003, China.
Chlorogenic acid (CGA) has strong antioxidant properties. In order to improve the low maturation rate and poor vitrification freezing effect of sheep oocytes caused by oxidative stress. In this study, oocytes from 200 2-3-year-old Kazakh sheep were collected, and different concentrations of CGA were added to the maturation medium and vitrification freezing solution to study the effects of CGA on the maturation rate, cleavage rate, blastocyst rate, reactive oxygen species (ROS) and glutathione (GSH) levels, mitochondrial membrane potential, and the expression levels of oxidation and apoptosis-related genes in sheep oocytes.
View Article and Find Full Text PDFHum Reprod
January 2025
IVIRMA Global Research Alliance, IVIRMA New Jersey, Basking Ridge, NJ, USA.
Study Question: Does the use of slush nitrogen (SN) for embryo vitrification improve embryo transfer outcomes compared to liquid nitrogen (LN)?
Summary Answer: SN is a safe method for embryo preservation and significantly improves post-warming survival rates during repeated vitrification-warming cycles; however, after a single freeze-thaw cycle, pregnancy outcomes are not improved when embryos are vitrified with SN compared to LN.
What Is Known Already: SN is a combination of solid and LN, with a temperature lower than regular LN, and it is an alternative to conventional LN in achieving a faster cooling speed. Studies have shown that SN improves survival in non-human embryos and human oocytes.
Background: An estimated 17% of all couples worldwide are involuntarily childless (infertile). The clinically identifiable causes of infertility can be found in the male or female partner or in both. The molecular pathophysiology of infertility still remains unclear in many cases but is increasingly being revealed by genetic analyses.
View Article and Find Full Text PDFBMJ Open
January 2025
Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, China
Introduction: Multimodal anticancer therapies greatly damage the fertility of breast cancer patients, which raises urgent demand for fertility preservation. The standard options for fertility preservation are oocyte and embryo cryopreservation; both require controlled ovarian hyperstimulation (COH). However, there are safety concerns regarding breast cancer relapse due to the elevated serum estradiol levels during COH.
View Article and Find Full Text PDFReprod Biomed Online
September 2024
Department of Assisted Reproductive Technologies and Fertility Preservation, Jeanne de Flandre Hospital, Lille, France; OncoLille, Canther, INSERM UMR-S1277, CNRS UMR9020, Lille University, Lille, France.
Research Question: Does the aggressiveness of Hodgkin lymphoma impact the oocyte cohort after ovarian stimulation for fertility preservation?
Design: A retrospective analysis of prospectively collected data was undertaken. Seventy-seven chemo-naive women with newly diagnosed Hodgkin lymphoma were enrolled prospectively at the Observatory and Fertility Preservation Centre, Lille University Hospital, France between 2012 and 2021. Seventy-eight ovarian stimulation cycles were performed.
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