Ma P, et al. - In order to characterize the metabolic features of semen abnormality (SA) male infertility, a blood plasma metabolomics method based on GC-MS, partial least squares-discriminant analysis (PLS-DA), and metabolic pathway analysis is proposed in this study. Researchers examined the utility of the blood plasma metabolomics in differentiating healthy controls (HC, n = 29) from SA patients, diagnosed as teratozoospermia (TE, n = 21), asthenozoospermia (AS, n = 23), oligozoospermia (OL, n = 20), azoospermia (AZ, n = 20). In addition, they investigated the potential biomarkers and metabolic pathways for deciphering the pathogenesis of SA male infertility. Multivariate statistical method (PLS-DA) and univariate statistical method (analysis of variance, ANOVA) with comparisons of TE vs HC, AS vs HC, OL vs HC and AZ vs HC, yielded 23 biomarkers indicating the most relevant pathways to be mainly linked with the metabolism of carbohydrates, amino acids, and lipids. Metabolic alternations principally observed in SA male infertility were increased levels of energy-related metabolisms, such as tricarboxylic acid cycle, pyruvate metabolism, glyoxylate and dicarboxylate metabolism, glycine, serine, threonine metabolism and saturated fatty acid metabolism. Furthermore, oxidative stress was noted to be correlated with increased levels of glutathione metabolism. Finally, they noted reduced levels of arginine and proline metabolism and inositol phosphate metabolism. These findings thereby suggest that metabolic disturbances in SA male infertility could be robustly characterized by blood plasma metabolomics. As per metabolic pathway analysis, SA male infertility was primarily correlated to energy production, oxidation stress and the released enzyme during spermatogenesis.