Follicular fluid levels of the long pentraxin PTX3

Pentraxin-3 (PTX3) is a long pentraxin that plays a key role in female fertility as a structural and essential constituent of the cumulus oophorus extracellular matrix. Despite considerable evidence supporting this role of PTX3 in mice, data in humans are scanty. The aim of the present study was (1) to evaluate follicular fluid concentrations of PTX3; (2) to test the hypothesis that levels of the molecule correlate with oocyte characteristics (corona radiata, aspect of the cumulus, nuclear maturity, and fertilization); and (3) to evaluate the possibility that peripheral concentration of PTX3 may be of clinical help in monitoring ovarian hyperstimulation.

ELISA was used to determine PTX3 concentration. Levels of PTX3 were tested in 96 follicles.

The mean +/- SD and the median (interquartile range) were 17.9 +/- 18.3 and 12.1 (6.5-23.6) ng/mL, respectively. Levels of the molecule did not appear to be normally distributed. At the day of ovum pick-up, levels of PTX3 were 6.3-fold higher in follicular fluid than in peripheral blood (95% CI, 3.6-9.0). No statistically significant difference emerged linking follicular fluid concentration of PTX3 and oocyte quality. In a series of ten women, plasma concentration of PTX3 did not vary during ovarian hyperstimulation, resulting in levels of 1.0 +/- 0.5 at the 3rd day of the menstrual cycle and 1.0 +/- 0.6 ng/mL at the day of oocyte retrieval.

Results from the present study support the following conclusions: (1) elevated levels of soluble PTX3 can be found in follicular fluid; (2) follicular fluid concentration of PTX3 cannot by used as a marker of oocyte quality; and (3) plasma concentration of the molecule is not influenced by ovarian hyperstimulation.