P-228 Higher oxidation levels in follicular fluid correlate with better outcome in ICSI treatments
Authors: De Los Santos J.M , Valera M.Á , Meseguer F , Alegre L , Paya E , Gámiz P , Meseguer M 
Published: June 2022

Abstract

Study question
Can the oxidative status of the follicular fluid be a valid biomarker of the quality of the oocyte cohort and clinical outcome in ICSI treatments?

Summary answer
The follicular fluid (FF) of oocyte cohorts that achieved at least one pregnancy, ongoing pregnancy and life birth have higher oxidative stress levels.

What is known already
The role of oxidative stress in female infertility is yet unclear, due to the numerous factors that participate in the production and activity of reactive oxygen species (ROS), and the different techniques used for its detection. The Fertissimo TCL AnalyzerTM (Carmel Diagnostics, Israel) uses thermochemiluminiscence to assess the oxidative status (OS) of biological samples by counting the photons emitted per second (cps) after a heat-catalyzed oxidative reaction. Using this technique, a negative correlation was found between ROS levels in FF and patient age (Wiener-Megnazi et al, 2004), but its potential as a biomarker of clinical outcome is unclear.

Study design, size, duration
Prospective observational study performed in a single IVF center during one year. 173 women were subjected to controlled ovarian stimulation as part of an autologous (103 patients) or ovum donation ICSI treatment (70 donors). The OS of the follicular fluid (FF) obtained in the oocyte retrieval was assessed and compared with the characteristics of the treatment and clinical outcome.

Participants/materials, setting, methods
The first tube of follicular fluid obtained in the oocyte retrieval was centrifuged (10 minutes at 600g) and the supernatant was analyzed in the Fertissimo TCL AnalyzerTM. OS results were normalized per volume and summarized as TCL-Score (average photon counting from 50-280s) and Ratio (slope of the reaction time curve). TCL parameters were compared with the demographics, number of oocytes retrieved and clinical outcome of the cohort using Pearsons Correlation and Anova tests

Main results and the role of chance
FF from donors had higher TCL-Score (44.27±14.41cps vs 40.59±11.65cps, P = 0.066) and Ratio (367.38±89.47 vs 329.88±78.12, P = 0.004) than patients. A significant inverse correlation was found between TCL Ratio and the age of the women (Pearsons Correlation Coefficient (PCC)=-0.207; P = 0.006). A direct significant correlation was found between the body mass index (BMI) and the TCL-Score (PCC=0.186, P = 0.014) and Ratio (PCC=0.186, P = 0.014). TCL-Score (PCC=0.173, P = 0.023) and Ratio (PCC= 0.275, P  &lt;0.001) also had a significant positive correlation with the number of mature oocytes retrieved. In donors, TCL Ratio was negatively correlated with the fertilization rate (PCC=-0.350, P = 0.009) and positively correlated with the blastocyst formation rate at day 5 (PCC=0.289, P = 0.032), but said correlation was not found in FF of patients (PCC(Ratio-Fertilization rate)=0.066, P = 0.554; PCC(Ratio- Blastocyst rate)=-0.005, P = 0.965). However, in patients, a statistically significant negative correlation was found between TCL-Score and the good quality blastocyst rate (PCC=-0.234, P = 0.038), which was not statistically significant in donors (PCC=-0.131, P = 0.342). Finally, TCL Ratio levels resulted significantly higher in FF of oocyte cohorts that resulted in at least one pregnancy (362.77±86.60 vs 321.90±77.60, P = 0.005), one ongoing pregnancy (365.99±84.10 vs 322.66±80.94, P = 0.003) and one life birth (364.93±83.74 vs 330.07±84.17, P = 0.017).

Limitations, reasons for caution
Some miscalibration issues were met in the course of the analysis, which may hinder its reproducibility. Stimulation protocol or sperm quality was not considered in the analysis. A larger scale, controlled trial should be performed to validate results.

Wider implications of the findings
Presented results are in tune with previously published data using similar and different techniques for assessing oxidative and antioxidative capacity in FF samples. The analysis of the oxidative status of the FF could be a valid biomarker of clinical outcome of ICSI treatments and as indicator for antioxidant therapy.

Trial registration number
APOTIP/2020/015 Generalitat Valenciana.