Scientists lifted fertility rates in older female mice

Reversing the reproductive clock in mice.


Reproductive aging in female mammals is an irreversible process associated with declining oocyte quality, which is the rate-limiting factor to fertility. In a new study, scientists have lifted fertility rates in older female mice with small doses of a metabolic compound that reverses the aging process in eggs, offering hope for some women struggling to conceive.

This non-invasive, pharmacological treatment to maintain or restore oocyte quality during aging would alleviate a rate-limiting barrier to pregnancy with increasing age that has driven demand for assisted reproduction technologies (ARTs) such as In vitro fertilization (IVF).

Also, the treatment could maintain or restore the quality and number of eggs and alleviate the most significant barrier to pregnancy for older women.

A team led by UQ’s Professor Hayden Homer said“Quality eggs are essential for pregnancy success because they provide virtually all the building blocks required by an embryo. We investigated whether the reproductive aging process could be reversed by an oral dose of a ‘precursor’ compound – used by cells to create the molecule.”

“The molecule in question is known as NAD (nicotinamide adenine dinucleotide) and the ‘precursor’ as NMN (nicotinamide mononucleotide).”

Scientists treated the mice with low doses of NMN in their drinking water over four weeks. This dramatically restores egg quality and increases live births during a breeding trial.

Professor Homer said, “Poor egg quality had become the single biggest challenge facing human fertility in developed countries. This is an increasing issue as more women are embarking on pregnancy later in life, and one in four Australian women who undergo IVF treatment are aged 40 or older.”

“IVF cannot improve egg quality, so the only alternative for older women at present is to use eggs donated by younger women.”

“Our findings suggest there is an opportunity to restore egg quality and, in turn, female reproductive function using oral administration of NAD-boosting agents – which would be far less invasive than IVF. It is important to stress, however, that although promising, the potential benefits of these agents remains to be tested in clinical trials.”

The study is published in the journal Cell Reports.