A Taiwanese team tested the mitochondrial fusion promoter M1 and observed improved maturation markers in aging oocyte models.
Changes in energy metabolism in surrounding granulosa cells point to a possible research direction for age-related infertility—not an established treatment.
Pregnancy becomes more difficult with age for reasons beyond a decline in egg number. An egg's ability to mature, fertilize and support healthy embryo development also changes. Could researchers improve some functions of eggs affected by aging?
A Taiwanese team has reported laboratory findings suggesting that modifying mitochondria, the structures responsible for cellular energy production, may improve maturation in aging oocyte models.
Researchers including a team at Kaohsiung Veterans General Hospital published their study of the mitochondrial fusion promoter M1 in Mitochondrion on October 17, 2026. They examined age-related changes in granulosa cells and oocytes.
M1-treated cells showed changes in mitochondrial shape and energy metabolism. Experiments with aging oocytes also showed increased polar body extrusion, a marker of maturation.
Mitochondrial dysfunction and egg aging
An oocyte is one of the largest cells in the female body. Maturation, fertilization and early embryo development require substantial energy, much of it supplied by mitochondria.
Mitochondria produce ATP, a molecule cells use as an energy source. Oocytes need this energy to separate chromosomes, progress through meiosis and prepare for development after fertilization.
Mitochondrial function can decline with age. Less efficient energy production and increased oxidative stress can create conditions unfavorable to maturation and development.
Granulosa cells surrounding the oocyte are also important. They support growth and maturation and regulate the hormonal and metabolic environment within the follicle. When their function declines, the oocyte may receive less of the support it needs.
This study examined mitochondrial function in both the oocyte and its supporting granulosa cells.
M1 altered mitochondrial structure and energy metabolism
M1 is an experimental compound known to promote mitochondrial fusion.
Mitochondria continually join and divide. The balance between fusion and fission contributes to energy production and maintenance of cellular function.
The researchers treated granulosa cell models showing age-related characteristics with M1 and observed mitochondrial changes.
Treated cells showed altered mitochondrial morphology and improvements in measures related to energy metabolism. Measurements of cellular respiration and ATP also changed.
The findings suggest that modifying mitochondrial structure and function can influence energy metabolism in aging cell models.
However, a change in shape or improvement in an energy-related marker does not establish that cellular aging has been reversed.
Increased polar body extrusion suggests a maturation effect
A particularly interesting observation concerned maturation in aging oocytes.
An oocyte progresses through meiosis on its way to becoming capable of fertilization. This process reduces the chromosome complement and produces a small cellular structure called a polar body.
Polar bodies also help embryologists assess maturity in IVF. An oocyte at metaphase II, usually identified by the presence of a first polar body, is classified as mature.
M1 treatment increased polar body extrusion in the aging oocyte experiments. This suggests a possible improvement in the ability to progress through meiosis and reach maturity.
Some measures related to oxidative stress and mitochondrial function also changed favorably.
Increased polar body extrusion is not, by itself, proof of better egg quality. A mature egg can still have chromosome abnormalities, and maturation does not guarantee normal fertilization or embryo development.
The results therefore concern maturation potential; they do not demonstrate improved pregnancy or live birth rates.
Could this approach eventually be used in IVF?
The number and quality of available eggs become important concerns as women age. Even after ovarian stimulation and retrieval, some eggs remain immature or fail to support normal embryo development after fertilization.
Research on improving maturation is therefore relevant to infertility associated with older age or reduced ovarian function.
If mitochondrial modulation can reliably improve maturation, it could offer a future research approach for in vitro maturation or treatments targeting ovarian aging.
Many questions remain before clinical use, however.
This study used cell and laboratory oocyte models. Whether M1 has the same effects in human oocytes, how it influences fertilization and embryo development, and whether long-term safety can be established remain unresolved.
M1 is not currently a medication with established clinical efficacy and safety for improving egg quality or treating infertility in older women.
Looking beyond chronological age to cellular metabolism
Egg aging has long been discussed mainly in relation to age and chromosome abnormalities. Researchers are also examining mitochondrial function, energy metabolism, oxidative stress and the follicular cellular environment.
This study asks whether some cellular functions that decline with age can be modified, rather than treating aging solely as the passage of time.
Oocyte aging involves multiple interacting biological changes. Improving mitochondrial function would not necessarily resolve chromosome abnormalities or every other age-related problem.
Nevertheless, the work presents an experimental possibility for improving maturation in aging oocytes.
Further investigation of M1's mechanism, safety and effects on fertilization and embryo development may support additional research into age-related infertility.
The ultimate test is whether changes in laboratory maturation markers can translate into the birth of healthy babies.
Source: Research on M1, ovarian aging and oocyte maturation by a team including Kaohsiung Veterans General Hospital, Taiwan. Mitochondrion, online October 17, 2026. DOI: 10.1016/j.mito.2026.102225.
These are basic laboratory findings, not evidence of improved human egg quality, pregnancy or live birth rates. Discuss clinical fertility decisions with a reproductive medicine specialist.
Related reading: How laboratory culture conditions support embryo development.
Copyright © 2026 Fertility Information TokTok Fertility News | THE FERTILITY NOTES. All rights reserved. Unauthorized republication, reproduction, redistribution, scraping, AI training and data use of any content, including articles, photographs and images, are strictly prohibited. Violations may result in legal liability.