Bringing New Life To Tired Eggs
Research and Innovations Since in vitro fertilization (IVF) was first introduced, 38 years ago, it has helped to create millions of families.
For many women, especially as our society has continued to trend towards starting families later in life than ever before, traditional IVF can prove insufficient as a fertility treatment on its own. The problem is that older eggs, and often younger eggs, have an energy deficiency and this interferes with forming a viable embryo.
“A woman’s eggs are sitting in her ovaries since birth,” says Dr. Robert Casper, Medical Director at TCART Fertility Partners in Toronto. “It’s like a flashlight sitting on a shelf in the closet. The flashlight itself may still be okay, but the batteries will have run down over time.
As women get older, and for other reasons, the amount of energy produced by the mitochondria, which are the batteries of the cell, starts to diminish. Age is an important factor in terms of prognosis for someone getting pregnant for that very reason.”
The energy provided by the mitochondria is required for both chromosomal separation and embryo development. “All the energy for an egg to go from the fertilized zygote stage at day one to the blastocyst stage at day five and then implantation at day six or seven comes from the mitochondria stored in the oocyte,” says Dr. Casper.
“The embryo doesn’t make any new mitochondria until day five or six. So an egg might have enough energy to get to, say, the eight cell stage, but by that point each of the cells only has one eighth of the mitochondria that started off in the egg.”
Recharging the batteries
What’s needed is a way to improve egg health and bring the energy levels back up to those of a younger cell. In 2004, the ground-breaking discovery of egg precursor cells, or immature egg cells, paved the way to making this possible. “We always thought that women were born with a set number of eggs that age and die over time.
We now know that women of every age have these egg precursor cells, which have the ability to mature into fresh, young, healthy eggs,” says Dr. Michelle Dipp, CEO and co-founder of OvaScience. “We can take these egg precursor cells from the ovarian cortex, which is the outer layer of the ovary, and use them in different ways.”
“In women with poor prognoses, meaning they didn’t have a good chance of achieving pregnancy, we saw an increase in pregnancy rates that were 11-to-18-fold higher than the women’s prior history.”
The egg precursor cells do not age in the same way as those in the middle of the ovary where the blood supply is rich do. This means that they can provide a source of fully charged egg mitochondria from within a woman’s own body.
A new fertility procedure called the AUGMENT treatment capitalizes on this. “With AUGMENT,” explains Dr. Dipp, “we take the mitochondria from the egg precursor cells and add them to the woman’s own egg during IVF.”
New Families are already being created
An AUGMENT IVF cycle is much like a regular IVF cycle. An ovarian biopsy is needed to access the egg precursor cells. The procedure takes about half an hour, with women walking out of the hospital the same day. Mitochondria from these cells are then injected into the woman’s mature eggs from the ovary at the time of fertilization during IVF.
The results speak for themselves. “In women with poor prognoses, meaning they didn’t have a good chance of achieving pregnancy, we saw an increase in pregnancy rates that were 11-to-18-fold higher than the women’s prior history,” says Dr. Dipp. In the field of fertility medicine, that is absolutely huge. The first baby conceived with AUGMENT treatment, Zain Rajani, was born in Toronto earlier this year, with many more to come.
And the technology is still developing. As the study of egg precursor cells continues, Dr. Dipp and Dr. Casper believe that the day may soon come when they can be used to grow entirely new healthy eggs outside of the woman’s body and without hormone injections. This has the potential to be the holy grail of fertility treatment.