Methods: Twenty-two patients (aged 41 - 64 years old) diagnosed with vasospastic angina with flow-mediated dilation (FMD) of the brachial artery (< 5.5 %) received 800 mg/day of L-citrulline for 8 weeks. FMD (%), blood NOx, asymmetric dimethylarginine (ADMA), small dense LDL, oxidized lipids, amino acids concentrations were measured before and after supplementation.
Results: Compared with baseline values, FMD (%) was significantly improved at 4 and 8 weeks as well as at 4 weeks after the end of intake. L-Citrulline supplementation caused a significant lowering of plasma ADMA levels. Plasma Larginine/ ADMA ratio and NOx levels rose markedly throughout the study period. Moreover, significant reductions of serum oxidized LDL and lectin-like oxidized LDL receptor 1 (LOX-1) ligand containing ApoB (LAB), an indicator of the biological activity of oxidized lipoprotein binding to LOX-1, were observed after L-citrulline intake.
Conclusions: L-Citrulline supplementation improves endothelial dysfunction, probably due to potentiating NO-dependent reactions and decreasing the state of lipoprotein oxidation in humans.