O-256 Evaluation of the fertility potential of semen using Proton NMR
Authors: Drzyzga D , Liss J , Zieliński K , Wieczorek D , Lipok J 
Published: June 2023

Abstract

Study question
Is Proton NMR seminal plasma assessment a valid method for identifying biomarkers allowing to predict top-quality (TQ) embryo development?

Summary answer
Biomarkers important in the context of male fertility can be assessed using proton NMR

What is known already
Currently, the quality of sperm is assessed predominantly by examining its concentration, motility, and morphology. These parameters are insufficient in diagnosing male infertility and predicting treatment outcomes with assisted reproductive technology (ART). Metabolomics techniques have been shown to be potentially useful in identifying biomarkers related to infertility. It has been proven, using proton NMR, that there are a number of substances in the semen plasma that correlate with various physiological states of patients and may potentially indicate impaired functioning of various metabolic pathways. However, the relationship between biomarkers and embryo development has not yet been investigated

Study design, size, duration
This was a prospective case-control study and consisted of 30 semen samples from 13 patients who underwent IVF treatment between January – March 2022 at INVICTA Fertility Centre, Poland. Sperm motility, concentration, morphology, and DNA fragmentation of the samples were assessed. Before sperm preparation for fertilization, semen was frozen to perform 1H NMR analyses, which were preceded by centrifugation in order to separate the plasma. NMR analysis results were compared to the embryological results.

Participants/materials, setting, methods
It was possible to identify pre-selected biomarkers in semen plasma through the use of reference spectra and to quantify their concentrations using the internal standard addition method. Their relative concentrations (separately and in pairs) were collated with semen parameters, embryo development data and pregnancy outcomes. A Machine Learning approach was employed to identify the most important variables, which were then used for further modelling with the use of LGBM models.

Main results and the role of chance
NMR allows for the identification and measurement of biomarkers important in the assessment of the fertility potential of semen. The presence of amino acids, organic acids, sugar residues and fatty acid derivatives was confirmed by applying this technique. It was found that the concentration of these biomarkers is an individual feature - probably dependent on the physiological state of the organism. The results indicate that the ratios of biomarker concentrations to each other are more important than their individual concentrations. Machine learning modelling showed a strong correlation of several compounds with the chance of obtaining a TQ blastocyst. The amount of taurine, glutamic acid and choline together with its derivatives seem to be the most important factors in blastocyst development. The results indicate that if the amount of glutamic acid significantly surpasses glycerophosphocholine, choline exceeds taurine, the amount of taurine is higher than that of citrate, or the amount of choline is significantly higher than its phosphorus analogue the likelihood of obtaining a TQ blastocyst is higher. This would suggest that several metabolic pathways as the Krebs cycle, the one-carbon cycle or choline metabolism were modified signalling pathological conditions which the standard assessment of semen parameters cannot detect.

Limitations, reasons for caution
The NMR technique allows a fast determination of the content of many biomarkers, but results are in the mmol/l range. The results should be confirmed in a larger group of patients with different semen disorders

Wider implications of the findings
NMR allows for the rapid creation of unique metabolic profiles of patients, which can ensure the creation of personalized treatments for male infertility and the selection of sperm with the highest chance of obtaining a TQ blastocyst

Trial registration number
The studies were approved by the Ethics Committee at the Gdansk Regional Medical Board (No KB-3/22).