Ovarian granulosa-cell genes and NMN: patient samples and cell research

Patient samples and a separate cell experiment

The study examined mitochondrial-gene expression in ovarian granulosa cells from women undergoing fertility treatment. It also included a separate laboratory experiment using an immortalized human granulosa-cell line.

These two parts must be distinguished. The women were not enrolled in a trial showing that oral NMN improved pregnancy or live-birth outcomes.

The patient groups

Forty-five women were classified into three groups: women aged 37 or older, younger women with a poor ovarian response, and younger women with a normal ovarian response. Granulosa cells were purified from follicular fluid collected on the day of oocyte retrieval.

The investigators assessed the expression of mitochondrial-encoded genes, including CYB, ND1, ATP6 and CO1, and nuclear-encoded genes involved in oxidative phosphorylation, including ATP5A1, SDHB, UQCRC1 and NDUFS8.

What was measured in the laboratory

Real-time quantitative PCR was used to measure mRNA expression. The researchers examined relationships with outcomes such as the number of oocytes retrieved, embryo quality, clinical pregnancy and live birth.

In the separate experiment, SVOG granulosa cells were exposed to NMN or to a small interfering RNA targeting NMNAT-1. This allowed investigation of NAD-biosynthesis-related mechanisms in cultured cells, rather than an oral intervention in patients.

Reported findings

Mitochondrial-encoded gene expression was lower in the older and poor-response groups than in the younger normal-response group. Higher expression was associated with retrieval of at least three oocytes or with obtaining higher-quality embryos in the reported comparisons.

In the cell experiment, NMNAT-1 knockdown reduced mitochondrial-encoded gene expression compared with the control conditions. Nuclear-encoded gene expression did not differ significantly across the relevant groups in the reported analyses.

Association is not evidence of a treatment effect

The patient-sample findings suggest that mitochondrial-related differences may accompany variations in ovarian response. They do not establish which changes are causes, consequences or markers of other processes.

Likewise, a cultured-cell response does not show that an oral NMN supplement improves egg quality, pregnancy rates or live birth. Those outcomes would require a properly designed clinical study, including an assessment of safety around conception and pregnancy.

Cited research: The mRNA expression of mitochondrial-encoded oxidative-phosphorylation genes in ovarian granulosa cells of infertile women and the effect of NMN on their expression in SVOG cells. This English edition preserves the distinction between the observational patient component and the cell intervention.