Serum Metabolites as Diagnostic Biomarkers in Patients with Endometriosis

Endometriosis diagnosis is usually delayed. The gold standard for diagnosing endometriosis is laparoscopy, which is invasive and accompanied by several risks. Currently, there are no effective non-invasive biomarkers for diagnosing endometriosis. Here, we investigated whether metabolites whose levels are altered in patients with endometriosis hold potential as diagnostic biomarkers for the disease. This case-control study involved 32 patients with endometriosis and 29 patients with other benign gynecological disease. The diagnosis of all patients was confirmed through postoperative histopathological examination, and the patients were divided into two groups: an endometriosis group (EM) and a control group. Fasting blood was collected and used for non-targeted metabolomic-based detection. The data were processed through principal component analysis, orthogonal partial least squares discriminant analysis, and significance analysis of microarrays. A univariate receiver operating characteristic curve was used to evaluate the diagnostic value of the metabolites. The metabolite profiles of patients with endometriosis were markedly different compared with those of the controls. In addition, several metabolic pathways, including biosynthesis of unsaturated fatty acids, arginine biosynthesis, and glutathione metabolism, were altered. Ornithine and medorinone showed better potential as biomarkers for endometriosis diagnosis than CA125. We analyzed the altered metabolic profiles in patients with endometriosis and found ornithine and medorinone as potential non-invasive biomarkers for endometriosis diagnosis, whereas the combined ornithine-medorinone diagnosis is more valuable. These findings may help advance research on non-invasive diagnostic biomarkers for endometriosis. Further research with an improved study design and a larger cohort should be performed to confirm the diagnostic potential and clinical application of these biomarkers.