Chromosomal meiotic segregation, embryonic developmental kinetics and DNA (hydroxy)methylation analysis consolidate the safety of human oocyte vitrification.

Oocyte vitrification has been introduced into clinical settings without extensive pre-clinical safety testing. In this study, we analysed major safety aspects of human oocyte vitrification in a high security closed system: (i) chromosomal meiotic segregation, (ii) embryonic developmental kinetics and (iii) DNA (hydroxy)methylation status. Fresh and vitrified sibling oocytes from young donors after intracytoplasmic sperm injection (ICSI) were compared in three different assays.

Recurrent chromosomal abnormalities in human embryonic stem cells.

Cultured human embryonic stem (hES) cells have a known predisposition to aneuploidy of chromosomes 12, 17 and X. We studied 17 hES cell lines by array-based comparative genomic hybridization (aCGH) and found that the cells accumulate other recurrent chromosomal abnormalities, including amplification at 20q11.21 and a derivative chromosome 18.