Ovarian environment aging: follicular fluid lipidomic and related metabolic pathways

The decline in female fecundity with age may be caused by decreased oocyte quality, a factor that may be associated with the altered composition of follicular fluid (FF).

In an effort to better understand follicular aging and the role of lipids in a given biological system, we present a prospective study that compares lipid profiles of FF from women older than 35 years (aging group, n = 12) to women equal or younger than 35 years old (control group, n = 17). FF lipids were extracted, and mass spectra were generated using a Waters Synapt G1 Q-TOF in MS mode. MS data was evaluated for both multi- and univariate statistics. The lipids identified as potential biomarkers of follicle aging were attributed by the online databases Lipid Maps, followed by pathway network analysis using Cytoscape software.

The in vitro fertilization (IVF) parameters showed significant differences in aging, number of follicles, total number of oocytes and oocytes in MII, and number of injected oocytes. Additionally, FF from the aging group revealed 11 lipids with higher abundance, while FF from the control group included 4 lipids with higher abundance.

We suspect that aging may influence lipid metabolism in a downstream cascade leading, ultimately, to decreased oocyte quality. The discovery of target lipids may assist oocyte selection for IVF in the future. Furthermore, systems biology approach based on post-genomic medicine may help unravel a number of altered mechanisms not previously understood.