Biochemical markers of vasospastic coronary artery disease

OBJECTIVE: The risk factors for vasospastic angina pectoris (VSA) have not yet been well defined. We compared the plasma levels of lipids, apo(lipo)proteins, remnants of triglyceride (TG)-rich lipoproteins, oxidized low density lipoprotein (Ox-LDL), cholesteryl ester transfer protein (CETP) [which transfers esterified cholesterol (EC) from HDL to TG-rich lipoproteins and reduces plasma HDL levels], high-sensitivity C-reactive protein (hs-CRP), homocysteine and plasminogen-activator inhibitor (PAI)-1 in background-matched groups of controls, and patients with VSA or coronary atherosclerotic disease (CAD) (n=50 subjects each). METHODS AND RESULTS: The cholesterol levels of remnant-like particles (RLP), which are equivalent to the remnants of TG-rich lipoproteins, were measured using a precipitation method. Ox-LDL, CETP and PAI-1 were measured by means of sandwich ELISA; hs-CRP by means of nephelometry; and homocysteine by means of HPLC. Plasma LDL-C levels were high only in the CAD group, and plasma apo E and PAI-1 levels were high only in the VSA group. The plasma levels of TG, apo CII and RLP-C were highest in the VSA group, followed by the CAD group. The plasma levels of apoB, apo CIII, Ox-LDL, CETP, hs-CRP and homocysteine were equally increased in both the VSA and CAD groups. The increases in plasma RLP-C, CETP, hs-CRP and homocysteine were not significantly different between stable and unstable states of angina pectoris in either the VSA or CAD group. CONCLUSION: The increases in plasma TG-rich lipoproteins and their remnants were more significant markers of VSA than of CAD. The increases in plasma CETP, Ox-LDL, hs-CRP and homocysteine were equally important markers of VAS and CAD.