Novel HPLC–laser-stimulated fluorescence profiling of seminal plasma amino acids linked to ejaculate quality

PURPOSE: Amino acids are vital biomolecules that can provide important insights into sperm functional competence. However, the level of amino acids (AAs) in seminal plasma and their implications on sperm characteristics remain less understood. METHODS: For the first time, high-performance liquid chromatography (HPLC) in combination with a laser-stimulated fluorescence (LSF) system was used to profile AAs from the seminal plasma of 30 normozoospermic and 51 nonnormozoospermic ejaculates. Sperm characteristics, along with DNA integrity, were assessed and correlated with individual AAs. RESULTS: The HPLC-LSF system was able to detect a total of 18 AAs in the seminal plasma. A significant variation was observed between the two groups for all AAs (p < 0.05), except for aspartate. Notably, the relative intensities of AAs were significantly lower in the non-normozoospermic group. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) further highlighted distinct clusters based on the AA profiles of the two groups. The pathway analysis indicated differences in the metabolic pathways between the normozoospermic and nonnormozoospermic groups. CONCLUSION: The HPLC-LSF platform could serve as a potential tool in identifying seminal plasma AA levels. The low relative abundance of AA in the non-normozoospermic men could be attributed to aberrant metabolic pathways, underscoring their significance in male infertility.