P–053 Concentration of bisphenol S in human seminal plasma negatively correlates with decreasing sperm concentration in ejaculate
Authors: Franzová K , Ješeta M , Navrátilová J , Fialková S , Kalina J , Žáková J , Ventruba P 
Published: August 2021

Abstract

Study question
Is there a relationship between concentration of bisphenol S in seminal fluid and spermiogram parameters?

Summary answer
Bisphenol S was detected in 81% of seminal plasma samples. Negative correlation was found between BPS concentration and total sperm count in normozoospermic men.

What is known already
Human spermatogenesis can be influenced by a range of chemicals present in our environment. Bisphenol S (BPS) is a very frequent compound commonly used as a softener in production of plastics, where it has replaced bisphenol A. It is an endocrine disruptor frequently associated with negative effects on reproduction. It has been observed that BPS can affect testicular development in rodent males. In addition, it has cytotoxic, reprotoxic and neurotoxic effects and induces the oxidative stress bringing negative effects on spermatogenesis. BPS has been detected in food, drinks or cosmetics. Its direct effect on spermatozoa or spermatogenesis is still unclear.

Study design, size, duration
A total of 38 patients (25 normozoospermic) aged 24 to 42 years, non-smokers, with BMI between 19,9–32,9 were included in this prospective study from 2018 to 2020. None of them had varicocele, urogenital infections or other urological problems. Their seminal plasma was separated by centrifugation. BPS was extracted using solvent extraction followed by preconcentration step. The samples were analysed on Agilent 6495 Triple Quadrupole. Two MS/MS transitions were used for quantitative LC-MS/MS analyses.

Participants/materials, setting, methods
All the men included in this study signed an informed consent and agreed with analyses of their samples. These analyses were approved by Ethical committee of University Hospital Brno. We evaluated the relationship between concentration of BPS in seminal plasma, sperm concentration, total sperm count, total motility, progressive motility, morphology and fragmentation of DNA in spermatozoa. Statistical evaluation was performed by one individual one-dimensional regression model (p-value lower than 0.05 were considered as statistically significant).

Main results and the role of chance
The examination revealed the presence of BPS in 31 samples of seminal plasma (81% of all the samples). In 6 samples, the concentration was under level of detection and in one sample under level of quantification. In 7 samples, a very high concentration was detected (&gt;0.1 ng/ml). These values were then compared to spermiogram parameters and sperm DNA integrity. There were no significant differences between the concentration of BPS and morphology of spermatozoa, progressive motility and total motility. In case of the DNA integrity, the opposite trend was observed, lower proportions of spermatozoa with fragmented DNA were found in samples with higher concentrations of BPS. Evaluation of sperm concentration and BPS concentration showed relationship of increasing BPS concentration with significantly lower sperm concentration, the differences were most obvious when only the normozoospermic men were compared. Evaluation of BPS concentration and total sperm count revealed the same trend with statistically significant difference in the category of normozoospermic men. Due to the small number of samples, a negative effect of extreme values on the statistical evaluation cannot be excluded. Currently, more analyses focused on detection of BPS in seminal plasma are carried out in order to obtain sufficiently larger data set.

Limitations, reasons for caution
A limitation is the number of samples included and analysed in this study, which slightly reduced the power of statistical analysis.
Wider implications of the findings: These results document that BPS was present in 81% of analysed samples. Knowing the concentration of BPS in seminal fluid is important for understandig of impact of BPS on male fertility. Our future work will be focused on detection of other bisphenols in seminal plasma.

Trial registration number
MH CZ – DRO (FNBr, 65269705), AZV NV18–01–00544, Czech Ministry of Education, Youth and Sports (CZ.02.2.69/0.0/0.0/19_074/0012727)