Author:

Keywords:

Science & Technology, Life Sciences & Biomedicine, Food Science & Technology, Toxicology, asymmetric dimethylarginine, symmetric dimethylarginine, UPLC-MS, MS, ELISA, chronic kidney disease, TANDEM MASS-SPECTROMETRY, PERFORMANCE LIQUID-CHROMATOGRAPHY, CORONARY-ARTERY-DISEASE, CHRONIC RENAL-DISEASE, HUMAN PLASMA, L-ARGININE, HPLC METHOD, ALPHA-1-ACID GLYCOPROTEIN, METHYLATED ARGININES, BIOLOGICAL SAMPLES, UPLC-MS/MS, Arginine, Chromatography, High Pressure Liquid, Enzyme-Linked Immunosorbent Assay, Humans, Renal Insufficiency, Chronic, Tandem Mass Spectrometry, 0601 Biochemistry and Cell Biology, 1115 Pharmacology and Pharmaceutical Sciences, 3214 Pharmacology and pharmaceutical sciences

Abstract:

Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide (NO) synthesis, and its structural isomer symmetric dimethylarginine (SDMA) are uremic toxins accumulating in chronic kidney disease (CKD) patients. The objective of this study was to develop and validate a robust UPLC-MS/MS method for the simultaneous determination of ADMA and SDMA in human serum. Chromatographic separation after butyl ester derivatization was achieved on an Acquity UPLC BEH C18 column, followed by tandem mass spectrometric detection. After validation, the applicability of the method was evaluated by the analysis of serum samples from 10 healthy controls and 77 CKD patients on hemodialysis (CKD5HD). Both ADMA (0.84 ± 0.19 µM vs. 0.52 ± 0.07 µM) and SDMA concentrations (2.06 ± 0.82 µM vs. 0.59 ± 0.13 µM) were significantly (p < 0.001) elevated in CKD5HD patients compared to healthy controls. In general, low degrees of protein binding were found for both ADMA and SDMA. In addition, an established commercially available ELISA kit was utilized on the same samples (n = 87) to compare values obtained both with ELISA and UPLC-MS/MS. Regression analysis between these two methods was significant (p < 0.0001) but moderate for both ADMA (R = 0.78) and SDMA (R = 0.72).