Cysteine is a better predictor of coronary artery disease than conventional homocysteine in high-risk subjects under preventive medication

Background and aims: In Portugal, The Azores Archipelago has the highest standardized mortality rate for CAD. Therefore, the aim of this study was to evaluate conventional risk factors, as well as plasma and erythrocyte aminothiol concentration in high-risk Azorean patients undergoing elective coronary angiography and to investigate whether any aminothiol was associated with CAD risk and severity. Methods and results: 174 subjects with symptomatic CAD (age 569y; 68% men) submitted to coronary angiography were split into 2 groups: one formed by CAD patients ( 50% stenosis in at least one major coronary vessel) and the other by non-CAD patients (<50% stenosis). Both groups were age-, sexand BMI-matched. Plasma and erythrocyte aminothiol profiles were evaluated by RP-HPLC/FLD. CAD patients significantly exhibited both higher concentrations of plasma Cys and hypercysteinemia (Cys > 300 mu M) prevalence than those in the non-CAD group (261 58 mu M vs. 243 +/- 56 mu M; 22% vs. 10%, respectively). No differences were observed between groups regarding plasma Hcy levels or hyperhomocysteinemia prevalence. After adjustment for several confounders (including Hcy), subjects in the highest quartile of plasma Cys had a 3.31 (95% CI, 1.32-8.30, p = 0.011) fold risk for CAD, compared with those in the lowest quartiles. Furthermore, plasma Cys levels (but not Hcy) tended to increase with the number of stenotic vessels (1VD: 253 +/- 64 mu M; 2VD: 262 +/- 52 mu M; 3VD: 279 +/- 57 mu M, p = 0.129). Conclusion: Hypercysteinemia revealed to be a better predictor of CAD than hyperhomocysteinemia. Moreover, plasma Cys showed to be a useful biomarker for CAD both in primary and secondary preventions, seeming to resist better than Hcy to oral medication therapy. (C) 2020 The Italian Diabetes Society, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.