In vitro maturation of human ova

Effects of In Vitro Maturation on Histone Acetylation in Metaphase II Oocytes and Early Cleavage Embryos

In vitro maturation (IVM) of oocyte is an effective procedure for avoiding ovarian hyperstimulation syndrome in patients with polycystic ovaries (PCOS) during in vitro fertilization (IVF). To investigate the influences of IVM on epigenetic reprogramming and to search for the possible reasons for the lower rates of fertilization and cleavage in IVM oocytes, we examined the expression of two enzymes controlling histone acetylation, histone acetyltransferase GCN5 (GCN5) and histone deacetylase 1 (HDAC1), as well as their common target, acetyl-histone H3 (Ac-H3), in mouse metaphase II (MII) oocytes and preimplantation embryos. Results showed that IVM downregulated the protein expression of GCN5 in MII oocytes and two-cell embryos and changed the distribution of GCN5 in two-cell embryos. Expression of HDAC1 mRNA in MII oocytes and two-cell embryos decreased in the IVM group. However, none of these changes persisted after two-cell embryos. Levels of Ac-H3 in both oocytes and embryos remained unchanged after IVM. Our studies indicated that IVM could affect the protein and gene expression related to histone acetylation in oocytes and early cleavage embryos. By function of selection, parts of the changes could be recovered in late embryo development.

In vitro oocyte maturation for the treatment of infertility associated with polycystic ovarian syndrome: the French experience

BACKGROUND

In vitro oocyte maturation (IVM) permits the use of immature oocytes in IVF. IVM does not require ovarian stimulation and so can be offered to patients at risk of ovarian hyperstimulation syndrome.

METHODS

For this indication, we carried out 45 cycles of IVM in 33 women with polycystic ovarian syndrome (PCOS).

RESULTS

A total of 509 cumulus-oocyte complexes was obtained; 276 (54.2%) oocytes matured in 24 h and 45 (8.8%) in 48 h. The normal fertilization (2PN) rate of oocytes matured in 24 and 48 h was 69.5 and 73.3% respectively. Among the 214 embryos obtained, 103 were transferred and 30 were frozen. Forty transfers were performed (2.5 embryos/transfer). Eleven women had a positive beta-hCG test (26.2% of pregnancies/puncture, 27.5% of pregnancies/transfer) and nine women had a clinical pregnancy (20.0% of pregnancies/puncture, 22.5% of pregnancies/transfer). Five babies have been born and one pregnancy is ongoing. Results of the clinical examination carried out at birth were normal.

CONCLUSIONS

Our results show that IVM may be offered as an alternative to conventional IVF and to ovarian drilling in women with PCOS. The role of IVM in the therapeutic armamentarium for this condition should be further clarified.