Targeted metabolomics analysis of 21 amino acids in serum of silicosis patients using HILIC-MS/MS

Silicosis is characterized by the formation of fibrotic lesions due to altered collagen synthesis, in which amino acids play a crucial role. However, targeted metabolomics studies of serum amino acids in silicosis patients remain limited. Herein, we developed a specific serum amino acid metabolomics assay for identifying differential amino acids as biomarkers, providing a sensitive and reliable basis for diagnosing silicosis. A hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) method for the simultaneous quantification of 21 amino acids in serum was established by optimizing chromatographic and sample preparation conditions. The method validation results showed good linearity (r > 0.99), recovery (78.3 %–128.4 %) and precision (1.27 %–13.01 %). The developed method was utilized to detect the levels of 21 amino acids in the serum of the silicosis patient group (SP; n = 104) and the healthy control group (HC; n = 118). The concentration of four amino acids (glutamate, arginine, aspartic acid and ornithine) was significantly different between the SP and the HC. Single diagnostic biomarkers exhibited area under the curve (AUC) values ranging from 0.712 to 0.892, while the glutamate-arginine combination achieved superior performance (AUC = 0.915, 86.1 % sensitivity, 90.0 % specificity). The aforementioned results indicate that four biomarkers were screened for the diagnosis of silicosis, with glutamate emerging as the most accurate single biomarker for predicting silicosis. The diagnostic performance was further enhanced by combining glutamate with arginine, which improved both sensitivity and specificity.