Research Unveils Longevity Mechanism in Human Eggs: A Breakthrough

In a groundbreaking study published on July 16, 2025, in *The EMBO Journal*, researchers have uncovered a remarkable mechanism that enables human eggs to remain viable for decades. The investigation, led by Dr. Elvan Böke, a Group Leader at the Center for Genomic Regulation (CRG) in Barcelona, involved analyzing over 100 freshly donated eggs. The findings suggest that human eggs cleverly slow their internal waste disposal systems, a strategy that helps them maintain cellular integrity and viability for up to 50 years.

According to the research, human females are born with approximately one to two million immature eggs, which decrease to a few hundred by the time of menopause. Each egg must endure a prolonged dormancy, often lasting decades, before it can contribute to a successful pregnancy. The study indicates that this longevity is supported by a unique energy-saving strategy whereby eggs deliberately reduce the activity of their cellular waste disposal units, namely lysosomes and proteasomes. This reduction in activity minimizes the production of reactive oxygen species (ROS), harmful molecules that can compromise cellular integrity and lead to DNA damage.

Dr. Gabriele Zaffagnini, the first author of the study, describes the research as revealing a "type of spring cleaning" that human eggs perform to preserve their quality. The study utilized fluorescent probes to monitor the activity of these cellular components in live eggs. Results showed that protein degradation activity was significantly lower in the eggs compared to their surrounding support cells, indicating a deliberate metabolic slowdown as they matured.

This research represents the largest dataset of healthy human eggs collected directly from donors, a notable advancement considering that previous studies often relied on artificially matured eggs, which may not accurately reflect natural egg behavior. The implications of these findings are significant for the field of reproductive medicine, particularly in improving in vitro fertilization (IVF) success rates. According to Dr. Böke, the prevailing advice for fertility patients often involves taking various supplements to enhance egg metabolism. However, the evidence supporting such practices is inconsistent. This study suggests that preserving the natural, low metabolism of eggs may actually yield better outcomes for fertility treatments.

The team plans to extend their research to include eggs from older donors and those from unsuccessful IVF cycles to further understand whether the efficiency of this waste disposal mechanism declines with age or disease. This future direction could offer critical insights into reproductive health and fertility treatments.

As the field of reproductive medicine continues to evolve, this new understanding of the intrinsic mechanisms safeguarding human egg longevity may pave the way for innovative approaches to fertility preservation and IVF success, ultimately benefiting countless individuals seeking to conceive. The study emphasizes the need for continued exploration into the cellular dynamics of human eggs, which remain one of the most enduring mysteries in reproductive biology.

**Sources:** - Dr. Elvan Böke, Group Leader, Center for Genomic Regulation (CRG), Barcelona. - Dr. Gabriele Zaffagnini, First Author, *The EMBO Journal*, 2025. - *The EMBO Journal*, Article: "The proteostatic landscape of healthy human oocytes", DOI: 10.1038/s44318-025-00493-2, July 2025. - Center for Genomic Regulation, Press Release, July 17, 2025. - ScienceDaily, Article: "Nature’s longevity hack: How human eggs stay fresh for 50 years", accessed July 17, 2025.