The impact of in-vitro maturation of oocytes on aneuploidy rate

Abstract

Chromosome abnormalities in embryos obtained through in-vitro maturation (IVM) of oocytes from 11 oocyte donors were compared with embryos from women undergoing fluorescence in-situ hybridization (FISH) analysis for sex selection. Thirty-three oocytes had reached metaphase II stage at 28-30 h (65%) and 27 were successfully fertilized by intracytoplasmic sperm injection. Blastomere biopsy was performed in 20 embryos (74%). For five embryos, two blastomeres were analysed, three of which were mosaic. FISH study revealed aneuploidies of chromosomes 13, 15, 16, 18, 21, 22, X and Y in 12 embryos (60%) and euploidy in the remaining eight (40%). The percentage of aneuploidies in the control group was 33%. Differences between IVM and control embryos were not statistically significant. The high incidence of chromosome abnormalities in embryos resulting from the IVM protocol may account for the low implantation rates reported by others. Although a greater incidence of miscarriage or congenital abnormalities in babies born alive following IVM versus conventional IVF has not been observed in previous studies, preimplantation genetic aneuploidy screening or prenatal chromosome studies may be recommended to these patients on the basis of the present results.

Whole-Chromosome Aneuploidy Analysis in Human Oocytes: Focus on Comparative Genomic Hybridization

“…CGH profiles from all of them were obtained displaying a global aneuploidy rate of 32.1% (17.85% for the MII stage oocyte and 39.2% for the IVM oocytes). Even though the difference between the 2 types of oocytes was not significant, it might support the proposed increase of aneuploidy after in vitro maturation, as previously cited [Li et al, 2006;Vlaisavljevic et al, 2007;Requena et al, 2009].…”

“…It is worth noting, though, that the in vitro maturation process per se may induce aneuploidy, probably due to meiotic spindle abnormalities [Li et al, 2006;Vlaisavljevic et al, 2007;Requena et al, 2009], so the analysis of IVM oocytes may overestimate the real aneuploidy rate.…”

Analysis of Chromosome Segregation, Histone Acetylation, and Spindle Morphology in Horse Oocytes

“…With this in mind, a survey of the methods used for investigating errors in chromosome segregation was conducted to search for the most appropriate technique to apply to horse oocytes. Four main techniques were found in the scientific literature: 1) chromosomal spreads 5,18,19 , 2) fluorescent in situ hybridization (FISH) 4,6,17,20 , 3) centromere count on monastrol-collapsed spindles 13,14,21,22 , and 4) chromosome fluorescence staining without chromosome count 23,24,25 .…”

Changes in histone H4 acetylation during in vivo versus in vitro maturation of equine oocytes

“…Although in vitro oocyte maturation is a very attractive reproductive technology that can potentially reduce the cost and risks of ovarian hyperstimulation associated with the administration of exogenous gonadotrophins Edwards, 2007), culture conditions can adversely impact in vitro oocyte maturation in human by increasing the aneuploidy rate, as already reported (Requena et al, 2009;Christopikou et al, 2010;Xu et al, 2010). Culture-induced effects on epigenetic regulation have been reported also in farm-animal-assisted reproduction, where the most striking example of alteration of the stability of genomic imprinting in the embryo is represented by the large offspring syndrome with in vitro conceived ovine and bovine animals (Young et al, 1998(Young et al, , 2001.…”