Comprehensive Metabolic Profiles of Seminal Plasma with Different Forms of Male Infertility and Their Correlation with Sperm Parameters

Abstract Metabolomics measurements of seminal plasma are widely used in diagnosis and finding of molecular mechanisms of male infertility. However, so far the limitation of metabolome coverage of analytical methods hinders comprehensive metabolite biomarker finding. Moreover, the widely used case-control comparison is not enough to unveil the detailed correlations of the metabolic changes with different sperm abnormalities. In this work, we aimed to have comprehensive metabolic profiling of seminal plasma to find the metabolomics difference between healthy controls and infertility case samples with different semen abnormities by liquid chromatography–mass spectrometry (LC–MS) detection with previously established new sample preparation procedure. Among 624 detected metabolite features, 63 potential biomarkers in various metabolite classes were found for infertility in seminal plasma by multivariate analysis. Interestingly, different infertility forms have different potential biomarkers with few in common, and most of potential biomarkers were found in oligo-astheno-teratospermia samples. To further find the association of the metabolomic changes with specific sperm abnormality, sperm parameters including sperm concentration, sperm deformity rate and sperm motility were also collected, and multivariate linear regression was used to find correlations between sperm parameters and potential biomarkers. Finally, levels of 17 metabolites were found to be significantly correlated with sperm parameters. Most of correlations agreed with previously reported mechanisms of infertility, such as correlation of acylcarnitines with sperm concentration and sperm deformity, and correlation of some antioxidants with sperm deformity rate and sperm motility. Some correlations were reported for the first time, such as negative correlations of isopentenyl pyrophosphate, 2-phosphoglyceric acid and γ-glutamyl-Se-methylselenocysteine with sperm deformity rate, and negative correlation of creatine riboside with sperm concentration. All the potential biomarkers were involved in 14 metabolic pathways playing important role in energy production, antioxidation, hormone regulation and sperm membrane. These results proved previously reported molecular mechanism (such as oxidative stress and energy production) and also gave new possible clues to the pathology of male infertility, which will benefit future etiology, diagnosis and treatment of male infertility.