title: Determination of Asymmetric and Symmetric Dimethylarginine in Serum from Patients with Chronic Kidney Disease: UPLC-MS/MS versus ELISA.
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).
authors.affiliation: Department of Organic Chemistry, Separation Science Group, Ghent University, Krijgslaan 281, S4-bis, B-9000 Ghent, Belgium. jente.boelaert@gmail.com.|Department of Internal Medicine, Nephrology Section, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent, Belgium. jente.boelaert@gmail.com.
authors.forename: Jente
authors.initials: J
authors.lastname: Boelaert
authors.affiliation: Department of Internal Medicine, Nephrology Section, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent, Belgium. eva.schepers@ugent.be.
authors.forename: Eva
authors.initials: E
authors.lastname: Schepers
authors.affiliation: Department of Internal Medicine, Nephrology Section, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent, Belgium. griet.glorieux@ugent.be.
authors.forename: Griet
authors.initials: G
authors.lastname: Glorieux
authors.affiliation: Department of Internal Medicine, Nephrology Section, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent, Belgium. sunny.eloot@ugent.be.
authors.forename: Sunny
authors.initials: S
authors.lastname: Eloot
authors.affiliation: Department of Internal Medicine, Nephrology Section, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent, Belgium. raymond.vanholder@ugent.be.
authors.forename: Raymond
authors.initials: R
authors.lastname: Vanholder
authors.affiliation: Department of Internal Medicine, Nephrology Section, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent, Belgium. frederic.lynen@ugent.be.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Lynen
mesh_terms: D001120:Arginine / Q000031:analogs & derivatives* / Q000097:blood; D002851:Chromatography, High Pressure Liquid; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D051436:Renal Insufficiency, Chronic / Q000097:blood*; D053719:Tandem Mass Spectrometry
chemical_list: C024917:symmetric dimethylarginine; C018524:N,N-dimethylarginine; D001120:Arginine
keywords: ELISA; UPLC-MS/MS; asymmetric dimethylarginine; chronic kidney disease; symmetric dimethylarginine