S1P is the ligand of S1P1.62 The interaction between S1P and S1P1 contributes to many important endothelial functions including nitric oxide-dependent vasodilation, endothelial adhesion, and angiogenesis.9,30,63 HDL is the primary carrier of S1P in plasma.28 We found that nHDL downregulated the expression of HDRACA through S1P1, and dHDL was less effective because it contained less S1P, as reported in previous studies.9,29 The plasma levels of both S1P and HDL were lower in patients with CAD than in healthy individuals; however, HDL levels decreased more than S1P levels. The gene discussed is S1PR1; the disease is coronary artery disorder.