Endocrine Abstracts

Infertility is a growing concern in Western countries. Several factors, including lifestyle habits and increased prevalence of chronic disorders associated with hormonal alterations, increased chronic inflammation and systemic oxidative stress (such as obesity and diabetes mellitus), are contributing to the reduction of reproductive potential among males in modern societies. Evidence suggests these factors negatively impact human sperm quality resulting in a combination of alterations in specific sperm features, namely in its motility. Asthenozoospermia is a common cause of fertility reduction and is characterized by a reduction in sperm motility (sperm total motility <40%). Sperm lipid metabolism is crucial for sperm motility and morphology as well as for sperm-oocyte interactions, although the relevance of lipid content of human spermatozoa is poorly understood. In this work, we aimed to compare sperm lipidome from asthenozoospermic and normozoospermic men and to identify lipid metabolites that correlate with sperm motility. Sperm samples from the male partner of couples seeking fertility counselling (n=57) were collected and sperm parameters were assessed accordingly to WHO guidelines. Sperm polar lipid content from asthenozoospermic (n=17) and normozoospermic (n=39) men was analysed by liquid chromatography-mass spectrometry. A total of 245 lipid molecular species were identified and quantified in sperm samples from both groups. Using a PCA model, we found a distinct lipid profile between asthenozoospermic and normozoospermic men. Sperm lipid analysis showed an increase in the lysophospholipid (LPL) content in asthenozoospermic men, whereas the phosphatidylethanolamine (PE) content was increased in normozoospermic men. The levels of several lipids, including lysophosphatidylcholine (LPC) 18:0, 18:1, 20:1, O(16:1) and O(18:2), and lysophosphatidylethanolamine (LPE) 20:1 and O(20:2) negatively correlated with sperm total motility. Contrarily, some PE lipids, including PE-P(36:4), PE-O(38:6), PE-O(38:7), PE-O(40:9), and PE(38:6), as well as acyl-carnitine (26:6) and fatty acid (20:3);3O showed a positive correlation with total sperm motility. Overall, our data show a different lipidomic profile in sperm from asthenozoospermic men. Asthenozoospermic sperm content in LPLs suggests altered lipid metabolism in these men, which might be associated with alterations in sperm membrane fluidity and consequent decrease in sperm motility. Moreover, LPL levels suggest that increased inflammation and oxidative status might be in the aetiology of asthenozoospermia. Our results suggest that alterations in lipid metabolism might be a potential cause for chronic disorders-related decreased sperm motility and male infertility.