Clinical application of human egg cryopreservation

Abstract

Clinical egg cryopreservation has been applied during a 4-year period with some limited success. Mostly mature and a few immature eggs were frozen slowly and thawed rapidly in 1,2-propanediol and sucrose, and subsequently inseminated by intracytoplasmic sperm injection (ICSI). Three studies were performed in which: (i) it was established that 55% of aged unfertilized mature eggs survive freezing; (ii) in 22 cycles of thawed donated eggs cryosurvival was 24% with 15 cycles reaching transfer, and five pregnancies were initiated, one of which went to term at 39 weeks with fraternal twin boys, and one remains ongoing at 37 weeks; and (iii) in five cycles, where in-vitro fertilization patients had some of their own eggs frozen/ thawed, cryosurvival of mature eggs was poor at only 2.2%, although 44% sibling germinal vesicle (GV) stage eggs survived. A normal female infant delivered at 40 weeks arose from transfer of two embryos where GV eggs underwent in-vitro maturation post-thaw and were fertilized by ICSI. Pregnancies reported here and by others indicate a burgeoning awareness of the potential benefits of egg cryopreservation, prompting cautious optimism for the future of this technology.

Extensive effects of in vitro oocyte maturation on rhesus monkey cumulus cell transcriptome

“…All or a subset of these markers could be adopted into a readily applicable PCRor protein expression-based assay that could be applied to small clumps of cumulus cells isolated from individual COCs. This could allow clinical selection of the highest-quality oocytes in situations that require fertilized embryos to be transferred (35) and may provide an invaluable means of evaluating oocyte quality after in vitro oocyte culture and IVM, for example, in the context of oncofertility programs (87), or efforts to manipulate germinal vesicle stage oocytes in emerging assisted reproduction methods involving microsurgery (40,43,73,80). These markers may also provide a means of optimizing reproductive biology approaches to enhance production of valuable agricultural species or enhance species conservation approaches.…”

High Survival Rate of Bovine Oocytes Matured In Vitro Following Vitrification

“…It would be a useful treatment option for women who are at risk of losing their ovarian function because of pelvic diseases, surgery or radio/ chemotherapy and could also avoid some of the moral and ethical problems posed by embryo freezing. Although several pregnancies and live births following freezing and thawing of human oocytes have been reported [1][2][3][4][5][6][7][8][9][10][11][12][13], human oocyte freezing as a technology is still considered to be at an early developmental stage. Improving pregnancy rates associated with the use of cryopreserved human oocytes would be a major advance in human ART.…”

“…Although live young have been produced from cryopreserved oocytes in the mouse using a slow Accepted for publication: September 22, 2004 Correspondence: R-C.Chian (e-mail:ri-cheng.chian@muhc.mcgill.ca) freezing [14], the method has met very limited success in other species [15,16] including humans [1][2][3][4][5][6][7][8][9]. Mammalian oocytes have proven to be more difficult to cryopreserve than cleavage-stage embryos [17], and the efficiency of oocyte cryopreservation in most species, except for the mouse, is still very low (for a review, see [18]).…”

The Historic Development and Incorporation of Four Assisted Reproductive Technologies Shaping Today′s IVF Industry

“…In the Gook et al [106] study, embryo transfers were not attempted but it is noteworthy that 43% of the ICSI-derived zygotes formed blastocysts, following slow freezing in 1.5 M propanediol. Based on Dr. Debra Gook's success, the evolution of oocyte freezing was rekindled with live births reported in the USA [108], and in Italy [109] where she had scientifically consulted in 1996. By the end of the 20 th Century, nearly every IVF Lab in the world possessed the capacity to perform ICSI and resolve most male factor infertility issues.…”