Grant: Operating Grant - Priority Announ - Institute of Human Dev, Child & Youth Health

A growing number of Canadian women are turning to in vitro fertilization (IVF) to help them have children. IVF typically requires injections for up to a month of follicle-stimulating hormone (FSH) and other drugs. These are stressful, and the drugs are expensive and may pose health risks to the woman or embryo. Therefore, clinics have begun to introduce a technique termed oocyte maturation in vitro. This technique requires no drugs and thus eliminates the associated stress, cost and health risks. Unfortunately, it is not yet very efficient - the 'take-home' baby rate is only half that of traditional IVF. Improving the quality of in vitro-matured oocytes is essential to enable the benefits of this technique to be realized. Most efforts to improve oocyte quality have focused on the culture conditions used for maturation. Largely overlooked has been that, although oocytes normally do not undergo maturation until after they have completed the preceding phase of development, termed growth, oocytes used for in vitro maturation are obtained before they have completed growth. Studies using animals have shown that when such precociously matured oocytes are fertilized, they become arrested and die during early embryonic development. We hypothesize that (1) in vitro-matured oocytes develop poorly because they are obtained before they have completed growth; and (2) when oocytes are allowed to complete growth in vitro before undergoing maturation and fertilization, they will develop as healthy embryos. To test our hypotheses, we will define (1) molecular differences between oocytes that have or have not completed growth; (2) the specific role of FSH in oocyte development; (3) conditions that allow oocytes to complete their growth in vitro so that, following maturation and fertilization, they will give rise to healthy embryos. We expect that the results can be directly translated to the clinic to improve the ability of in vitro-matured oocytes to produce healthy infants.