Scientists ‘Rejuvenate’ Human Eggs in Breakthrough for IVF Success
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A groundbreaking new technique offers hope for older women undergoing IVF, with scientists claiming to have successfully “rejuvenated” human eggs and significantly reduced genetic errors. The research,presented at the British Fertility conference in Edinburgh on Friday and published as a preprint on Biorxi,addresses a primary obstacle for women seeking fertility treatment,particularly as they age. For women under 35, the average birthrate per embryo transferred in IVF is 35%, but this plummets to just 5% for those aged 43-44, according to recent UK figures. The average age of women starting IVF treatment in the UK is now over 35, highlighting the growing need for innovative solutions.
Researchers focused on a process called meiosis, where egg cells halve their genetic material in preparation for fertilization. This requires 23 pairs of chromosomes to align precisely. However, in older eggs, these chromosome pairs become unstable, leading to chaotic separation during cell division and resulting in embryos with an incorrect number of chromosomes.
“Most women in their early 40s do have eggs, but nearly all of the eggs have incorrect chromosome numbers,” explained a lead researcher. “This was the motivation for wanting to address this problem.”
The team discovered that a protein called Shugoshin 1, which acts as a “glue” holding the chromosome pairs together, diminishes with age. By microinjecting Shugoshin 1 into donated eggs, they observed a remarkable improvement. The number of eggs exhibiting the chromosomal defect decreased from 53% in the control group to 29% in the treated group.
Promising Results, Further Trials Needed
While the results are encouraging, scientists caution that further research is necessary. When analyzing eggs specifically from women over 35, the trend remained consistent – a reduction from 65% to 44% – but the difference was not statistically meaningful, likely due to the limited number of eggs (nine) treated in that age range.
“Overall we can nearly halve the number of eggs with [abnormal] chromosomes. That’s a very prominent improvement,” stated a director at the Max Planck Institute for Multidisciplinary Sciences in Göttingen and co-founder of Ovo Labs, the company aiming to commercialize the technique. “What is really beautiful is that we identified a single protein that, with age, goes down, returned it to young levels and it has a big effect. We are just restoring the younger situation again with this approach.”
The approach will not extend fertility beyond menopause, when the egg reserve is depleted.Currently, the only widely available solution for many women facing infertility is repeated IVF cycles, hoping for cumulative success.
“Currently, when it comes to female factor infertility, the only solution that’s available to most patients is trying IVF multiple times so that, cumulatively, your likelihood of success increases,” said a co-founder and co-CEO of Ovo Labs. “What we envision is that many more women would be able to conceive within a single IVF cycle.”
Looking Ahead
The team is now in discussions with regulators about initiating a clinical trial to assess the safety and efficacy of the technique. A key question will be whether the improved egg quality translates to fewer genetic errors in resulting embryos.
dr. Güneş Taylor, of the University of Edinburgh, who was not involved in the research, described the findings as “really promising.” “This is really critically important work as we need approaches that work for older eggs because that’s the point at which most women appear,” she said. “If there’s a one-shot injection that substantially increases the number of eggs with properly organised chromosomes, that gives you a better starting point.”
While microinjections into eggs are not currently standard practice outside of ICSI, researchers anticipate minimal safety concerns. this innovative approach represents a significant step forward in reproductive technology, offering a potential pathway to improved IVF success rates and a greater chance of parenthood for older women.
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