A novel NMR-based assay to measure circulating concentrations of branched-chain amino acids: Elevation in subjects with type 2 diabetes mellitus and association with carotid intima media thickness

• Published in: Clinical biochemistry Vol. 54; pp. 92 - 99
• Main Authors: Wolak-Dinsmore, Justyna, Gruppen, Eke G., Shalaurova, Irina, Matyus, Steven P., Grant, Russell P., Gegen, Ray, Bakker, Stephan J.L., Otvos, James D., Connelly, Margery A., Dullaart, Robin P.F.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.04.2018
• Subjects: Branched-chain amino acids; Carotid intima media thickness; Metabolic syndrome; Nuclear magnetic resonance spectroscopy; Type 2 diabetes mellitus; CLSI; LOD; T2DM; cIMT; CAD; Nuclear magnetic resonance spectroscopy; Type 2 diabetes mellitus; Metabolic syndrome; ppm; LOQ; CVD; HDL; LC-MS/MS; Branched-chain amino acids; NMR; CV; MetS; TG; LDL; Carotid intima media thickness; BCAA; CLIA; LOB; BMI
• ISSN: 0009-9120; 1873-2933; 1873-2933
• DOI: 10.1016/j.clinbiochem.2018.02.001

Plasma branched-chain amino acid (BCAA) levels, measured on nuclear magnetic resonance (NMR) metabolomics research platforms or by mass spectrometry, have been shown to be associated with type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD). We developed a new test for quantification of BCAA on a clinical NMR analyzer and used this test to determine the clinical correlates of BCAA in 2 independent cohorts. The performance of the NMR-based BCAA assay was evaluated. A method comparison study was performed with mass spectrometry (LC-MS/MS). Plasma BCAA were measured in the Insulin Resistance Atherosclerosis Study (IRAS, n = 1209; 376 T2DM subjects) and in a Groningen cohort (n = 123; 67 T2DM subjects). In addition, carotid intima media thickness (cIMT) was measured successfully in 119 subjects from the Groningen cohort. NMR-based BCAA assay results were linear over a range of concentrations. Coefficients of variation for inter- and intra-assay precision ranged from 1.8–6.0, 1.7–5.4, 4.4–9.1, and 8.8–21.3%, for total BCAA, valine, leucine, and isoleucine, respectively. BCAA quantified from the same samples using NMR and LC-MS/MS were highly correlated (R2 = 0.97, 0.95 and 0.90 for valine, leucine and isoleucine). In both cohorts total and individual BCAA were elevated in T2DM (P = 0.01 to ≤0.001). Moreover, cIMT was associated with BCAA independent of age, sex, T2DM and metabolic syndrome (MetS) categorization or alternatively of individual MetS components. BCAA levels, measured by NMR in the clinical laboratory, are elevated in T2DM and may be associated with cIMT, a proxy of subclinical atherosclerosis. •A novel NMR-based BCAA assay was developed for use in the clinical laboratory.•The clinical NMR BCAA assay exhibits good performance characteristics.•BCAA quantified using both NMR and LC-MS/MS were highly correlated.•High NMR-measured BCAA levels relate to T2DM and MetS in 2 independent cohorts.•cIMT was associated with BCAA independent of age, sex, T2DM and MetS categorization.