Women around the world who have reached their late 30s or 40s and want to have a baby worry about their biological clocks that make achieving a pregnancy much more difficult.
But what if women could press “Pause” on their biological clocks and give themselves more time to reach their goal?
Human eggs begin to mature from the onset of a woman’s first menstrual period. Yet, most 13-year-old girls in Western countries are not keen on having babies; while they wait, their ova age and the quality of their eggs declines. But what if there were a way to delay egg aging without losing egg quality?
Researchers at the Hebrew University of Jerusalem genetic department have discovered – in worms – the switch that may do this. And they are hopeful that this breakthrough may eventually help women extend their fertility limits and maintain high egg quality into their thirties and forties.
Dr. Yonatan Tzur and associate Dr. Hanna Achache, along with scientists at Harvard Medical School, studied egg maturation in roundworms and published their findings in the scientific journal Genetics.
Why worms? These tiny C. elegans invertebrates have been incredibly helpful in helping scientists understand human genetics, as they contain the same number of genes as humans do (20,000), and their eggs mature in about one day.
Tzur and his team monitored the changes in each of the worm’s 20,000 genes during egg formation and were able to pinpoint an exact gene (ogr-2) that controls the rhythm of egg maturation. Going deeper, the team studied MAP Kinase (“MAPK”), the biochemical switch that turns egg development on and off. When they removed the ogr-2 gene with CRISPR gene-editing technology, MAPK went into overdrive and the worms’ eggs aged very quickly.
“We tested the gene’s role by removing it from the worm’s gene sequence. Instantly, these ‘edited’ worms became less fertile and their eggs more closely resembled those of an older worm,” explained Tzur.
These findings are significant because aging egg cells is the main cause of birth defects, miscarriages, and infertility. As human eggs age, abnormalities develop.
While in-vitro fertilization (IVF) allows doctors to select the best eggs, women above the age of 35 have a harder time producing a healthy baby with their own ova, and for women aged 42 and older, their chances of a healthy pregnancy are close to zero. These statistics, along with the fact that the average age of first-time mothers in the Western world is increasing sharply, means finding the key to slowing down egg maturation is crucial and has spurred scientists like Tzur to discover the mechanisms that control ovarian development and oocyte aging.
Though still in its early stages, Tzur sees two possible applications of his discovery for humans. One is to gently increase the equivalent of ogr-2 in girls via a food additive. This may allow girls to maintain the high quality of young eggs until they’re ready to use them. Another would be to suppress MAPK during IVF cycles. This would help older eggs complete their development and improve women’s’ chances of having a healthy baby as they get older.
