Revitalizing Aging Maternal Eggs: The Promise of NMN Supplementation
At the foundation of human life lies the oocyte—an immature egg cell with the potential to mature into an ovum or egg. As women advance in age, a significant dip in the quality of oocytes is experienced, and effective methods to improve this quality are conspicuously scarce.
A groundbreaking research published in Cell Reports in 2020 unveils the promising impact of nicotinamide mononucleotide (NMN)—a precursor to nicotinamide adenine dinucleotide (NAD+)—in significantly enhancing the quality of aging oocytes in mice. This discovery lays the groundwork for improving reproductive outcomes in women of advanced maternal age. As the researchers behind the study confidently assert, "NMN holds considerable potential for boosting fertility in older women and enhancing the success rate of assisted reproductive technologies."
The Quintessence of High-Quality Oocytes in Successful Fertilization
High-quality oocytes play a vital role in successful fertilization and the subsequent stages of embryonic development, forming the foundation for the emergence of life. In most mammals, female reproductive aging is marked by a significant decrease in the quality and quantity of oocytes and the ovarian follicles that house them. Unfortunately, low-quality oocytes have become an endemic issue for women of advanced maternal age and are the chief culprit behind subpar reproductive outcomes. Despite the gravity of this problem, few studies have been dedicated to preserving oocyte quality with age.
NAD+, NMN, and their Impact on Aging
NAD+ is a pivotal molecule in metabolism and plays a critical role in a wide range of physiological processes, including maintaining genomic stability and cell survival. Notably, it has been observed that NAD+ levels decline with age across numerous tissues, and this decline is linked to various age-related diseases. Consequently, rejuvenating NAD+ levels could be a key approach to counteract aging.
NMN, a precursor to NAD+, is known to bolster NAD+ levels within cells when administered. There is growing evidence indicating that NMN treatment enhances NAD+ biosynthesis, which in turn reverses age-related dysfunctions in various organs in aged mice. Despite significant advances in understanding NMN's role in aging, its impact on female reproductive aging remained largely undetermined—until now.
Revitalizing Aging Oocytes: The Role of NMN
Prior research revealed that maternally aged mice exhibit reduced NAD+ levels in oocytes. However, this decline could be reversed with NMN administration, thereby improving oocyte quality. NMN supplementation showed promising results by moderately increasing the count of ovarian follicles, ovulated oocytes, and matured oocytes showing lesser fragmentation.
In this study, researchers noted a stark reduction in the number and maturation rate of ovulated oocytes due to maternal aging, accompanied by an increased incidence of fragmented oocytes, which ultimately leads to cell death. However, supplementation of NMN showed significant improvements in the maturation rate, number, and fragmentation of aged oocytes. Moreover, it was observed that NMN supplementation also increased the number of follicles, countering the impairment caused by maternal aging.
The Broader Implications of NMN Supplementation
A noteworthy finding of the study was that NMN supplementation enhanced the fertilization ability of aged oocytes and significantly boosted their subsequent embryonic development. Additionally, researchers observed improved formation rates of blastocysts—cell groups formed in early mammalian development—from fertilized oocytes of aged mice.
The research identified that the mechanism through which NMN worked to rejuvenate aged oocytes was by reinvigorating the distribution and function of mitochondria—the powerhouse of cells.
NMN supplementation mitigated the buildup of reactive oxygen species—volatile molecules that can cause cellular damage—thereby reducing DNA damage and preventing cell death.
Conclusion: The Promise of NMN for Aged Females and Assisted Reproductive Technology
The discoveries derived from this study suggest a potent approach for improving the fertility of older females and obtaining a higher yield of quality oocytes for assisted reproductive technologies.
In sum, the researchers concluded that "NMN supplementation presents a promising strategy to safeguard oocytes against the detrimental effects of advanced maternal age, thereby improving reproductive outcomes in older women and assisted reproductive technologies."