Urinary metabolome identifies signatures of oligozoospermic infertile men

Objective To identify the differential urinary metabolic pattern of oligozoospermic infertile men and to determine the potential biomarkers indicative of infertility. Design Observational study. Setting University hospital. Patient(s) Totals of 158 fertile volunteers and 135 oligozoospermic infertile men. Intervention(s) None. Main Outcome Measure(s) Urinary metabolic profiles were acquired with the use of liquid chromatography/mass spectrometry. Potential oligozoospermic biomarkers were screened from orthogonal projections to latent structures discriminant analysis and further evaluated by receiver operating characteristic analysis. The Spearman correlations between the individual sets of biomarkers and between biomarkers and sperm parameters were investigated. The disrupted biologic pathways which the biomarkers were involved in also were analyzed. Result(s) Oligozoospermic infertile men could be differentiated from fertile control subjects based on altered urinary metabolic profiles. A total of ten potential biomarkers were screened and tentatively identified. Among those, decreased acylcarnitines, aspartic acid, and leucylproline and increased adenine and methylxanthine were strongly associated with oligozoospermic risk. Many biomarkers were associated with sperm concentration and amplitude of lateral head displacement. The combined pattern of acetylcarnitine, carnitine C3:1, and aspartic acid provided moderate diagnostic power. Conclusion(s) Urinary metabolomics identified unique metabolic pattern of oligozoospermic infertility. The potential biomarkers suggested that oligozoospermia may be tightly associated with energy consumption and antioxidant defenses in spermatogenesis.