Increased plasma osteoprotegerin levels are associated with the presence and severity of acute coronary syndrome

Objective - The objective of this study was to explore the relationship between increased plasma osteoprotegerin (OPG) levels and acute coronary syndrome (ACS). Methods - Plasma OPG levels from 85 subjects undergoing coronary artery angiography in three different groups, including ACS (n = 45), stable angia pectoris (SAP) (n = 20) and normal coronary artery (NCA) (n = 20), were detected by ELISA. Twenty-two ascending aorta specimens were surgically taken from 8 ACS, 7 SAP and 7 NCA patients, and OPG mRNA expression in the specimens was detected by RT-PCR. In addition, 10 coronary artery sections each were selected from autopsy archives for the presence of vulnerable atherosclerosis plaques (VP), stable plaques (SP) or no plaques (NP) and OPG protein expression in the sections was detected by immunohistochemistry. Results - Plasma OPG concentrations in the ACS group were significantly higher than those in the SAP or NCA group. The levels of plasma OPG in the 1-, 2- and 3-vessel disease subgroups of ACS were increasingly higher (P < 0.05 or 0.01). Multiple logistic regression analyses revealed a significant independent relation between plasma OPG concentration and the presence of ACS (P = 0.032, odd ratio = 1.006). Ascending aorta specimens from the ACS group had a greater OPG mRNA expression than those from the NCA or SAP group (P < 0.01). Sections with VP had a markedly higher OPG expression than sections with SP or NP (P < 0.05 and P < 0.01, respectively). Conclusions - Increased plasma osteoprotegerin levels are associated with the presence and severity of acute coronary syndrome.