Plasma arginine metabolites in health and chronic kidney disease.

Abstract

Elevated plasma asymmetric and symmetric dimethylarginine (ADMA and SDMA) are risk factors for chronic kidney disease (CKD) and cardiovascular disease. Using plasma cystatin C (pCYSC)-based estimated glomerular filtration rate (eGFR) trajectories, we identified a cohort at high risk of poor kidney-related health outcomes amongst members of the Dunedin Multidisciplinary Health and Development Study (DMHDS). We therefore examined associations between methylarginine metabolites and kidney function in this cohort. ADMA, SDMA, L-arginine and L-citrulline were measured in plasma samples from 45-year-olds in the DMHDS cohort by liquid chromatography-tandem mass spectrometry. In a healthy DMHDS subset (n=376), mean concentrations were: ADMA (0.40±0.06µmol/L), SDMA (0.42±0.06µmol/L), L-arginine (93.5±23.1µmol/L) and L-citrulline (24.0±5.4µmol/L). In the total cohort (n=857), SDMA correlated positively with serum creatinine (Pearson's r=0.55) and pCYSC (r=0.55), and negatively with eGFR (r=0.52). A separate cohort of 38 patients with stage 3-4 CKD (eGFR 15-60mL/min/1.73 m2) confirmed significantly higher mean ADMA (0.61±0.11µmol/L), SDMA (0.65±0.25µmol/L) and L-citrulline (42.7±11.8µmol/L) concentrations. DMHDS members classified as high-risk of poor kidney health outcomes had significantly higher mean concentrations of all four metabolites compared with individuals not at risk. ADMA and SDMA individually predicted high-risk of poor kidney health outcomes with areas under the ROC curves (AUCs) of 0.83 and 0.84, and together with an AUC of 0.90. Plasma methylarginine concentrations facilitate stratification for risk of CKD progression.