Arachidonic and linoleic acid derivatives impact oocyte ICSI fertilization--a prospective analysis of follicular fluid and a matched oocyte in a 'one follicle--one retrieved oocyte--one resulting embryo' investigational setting

Abstract

Objective: To evaluate human oocyte ability to undergo fertilization and subsequent preimplantation embryonic development in relation to a wide panel of follicular fluid (FF) arachidonic acid derivatives (AAD) and linoleic acid derivatives (LAD) of prospectively selected patients undergoing intracytoplasmic sperm injection (ICSI).

Methodology: Study was designed as a two center (a university clinic and a private clinic) prospective study. 54 women of 181 consecutive couples undergoing ICSI were prospectively found to be eligible for analysis. 'One follicle - one retrieved oocyte - one resulting embryo' approach was used. Each individual follicle was aspirated independently and matched to an oocyte growing in this particular follicular milieu. FF samples were assessed for AAD and LAD by high-performance liquid chromatography; additionally, activity of secretory phospholipase A (sPLA2) was determined by enzyme-linked immunosorbent assay.

Principal findings: Increased activity of sPLA2 and significantly higher AAD and LAD levels were found in FF of oocytes that did not show two pronuclei or underwent degeneration after ICSI in comparison to oocytes with the appearance of two pronuclei. Receiver operating characteristics curve analysis identified acids with the highest sensitivity and specificity: 5oxo-hydroxyeicosatetraenoic, 16-hydroxyeicosatetraenoic, 9-hydroxyoctadecadieneoic and 12-hydroxyeicosatetraenoic. No significant differences between AAD and LAD related to embryo quality were found.

Conclusions/significance: Our study demonstrates for the first time that elevated concentrations of AAD and LAD in FF at the time of oocyte retrieval significantly decrease the ability of oocytes to form pronuclei after ICSI. This may serve as a new tool for non-invasive assessment of oocyte developmental capacity. However, levels of AAD and LAD are not associated with subsequent embryo quality or pregnancy rate, and therefore more studies are needed to determine their usefulness in human IVF procedure.

Fig 1. Follicular fluid arachidonic acid and linoleic acid pathways.

Abbreviations: COX: cyclooxygenase; CYP-450: cytochrome P–450; DiHETEs: dihydroxyeicosatetraenoic acids; EETs: epoxyeicosatrienoic acids; HETE: hydroxyeicosatetraenoic acid; HODE: hydroxyoctadecadienoic acid; LOX—lipoxygenase, LTX: lipoxin, PG: prostaglandin; TX: thromboxane.

Fig 2. Comparison of HETE/HODE/LTX mean concentrations in follicular fluid of fertilized, unfertilized and degenerated oocytes after ICSI.

U Mann Whitney: * p<0.001 for difference between fertilized and unfertilized oocytes; ** p<0.001—for difference between fertilized vs. degenerated oocytes. HETE: hydroxyeicosatetraenoic acid, HODE: hydroxyoctadecadienoic acid, LTX: lipoxin, FF: follicular fluid