Ovarian Club X and CoGEN in Asia

SpeakerS

Marc-André SIRARD (Canada)

After graduated studies at University Laval on in vitro fertilization to generate the first clinical method to produce test-tubes calves in 1985, he went for a post-doctoral training in Wisconsin to study in vitro maturation of oocytes.  He came back to Québec in 1987 and became a industrial chair professor in 1990.He founded the Centre de Recherche en Biologie de la Reproduction in 1995 which has grown to include more than 100 people today. He obtained a senior Canadian Research Chair in 2000 on genomics applied to reproduction and has led The EmbryoGENE strategic network  on mammalian embryos. He has published over 281 scientific papers and has been invited to give over 75 invited lectures in international meetings. His current research activities are focus on the influence of the ovarian environment on oocyte quality in human and large animals.  

Abstract

How to Synchronize Oocytes In GV2 for Maximal IVM Results

The use of IVM in human ART has been impaired with limited success and confusion about the means and timing of oocyte recovery. In animal models like mouse or bovine, the IVM procedure has been optimized to the point where it equals the success rates of  in vivo maturation. In addition the bovine models permits experiments not possible on humans but very relevant to understand the process of oocyte preparation to ovulation. Recent analysis both at the molecular and microscopic level indicates that actively growing follicles with a high rate of cell division in granulosa cells are associated with oocyte that have not completed their transcription program and still in chromatin configuration (GV-1) that is not optimal for immediate meiotic resumption.  Once the follicle reaches dominancy or prepare for ovulation, the follicle starts to differentiate in preparation to form a corpus luteum and although follicular size keep increasing the cell division decreases. This second phase of follicular development is associated with oocytes with a more condensed chromatin (GV2) which demonstrate superior competence towards embryonic development. If the follicles is not selected for ovulation (subordinate) or if gonadotropin support is removed , the oocyte will also transform into a GV2 chromatin status but will rapidly  move to a GV-3  configuration (even more condense)  where the quality of the oocyte will be rapidly lost.  These observations in the bovine model are useful to explain the success and failure of different IVM protocols in human and indicate that creating conditions to increase the proportion of GV2 prior to collection would probably increase the developmental potential of the immature human oocytes.