OBJECTIVETo observe the expression and clinical implication of receptor for activated C kinase 1 (RACK1) in mononuclear cells and coronary atherosclerotic plaques from patients with coronary artery disease.

METHODSmRNA and protein expressions of RACK1 were detected in mononuclear cells from 29 patients with stable angina pectoris (SAP), 41 patients with acute coronary syndrome (ACS) and 30 healthy volunteers. RACK1 protein expression was also detected by immunohistochemistry in 17 coronary atherosclerotic plaques and 6 normal autopsy coronary samples.

RESULTS(1) mRNA expression of RACK1 was significantly upregulated in mononuclear cells from patients with ACS compared with those from patients with SAP (18.71 ± 5.45 vs. 12.18 ± 4.14, P < 0.05), and the latter was also significantly higher than in healthy controls (12.18 ± 4.14 vs. 3.65 ± 1.57, P < 0.05). (2) Similar changes were observed for protein expression of RACK1 for the three groups. (3) Increased expression of RACK1 was found in atherosclerotic plaques, especially in unstable plaques, positive RACK1 stain was evidenced in foam cells, inflammatory cells, smooth muscle cells and endothelial cells.

CONCLUSIONSThe expression of RACK1 is significantly upregulated in mononuclear cells from patients with coronary artery disease, especially in patients with ACS, and in coronary atherosclerotic plaques, especially in unstable plaques. Our results thus suggest that RACK1 might play an important role in the development and progression of coronary artery disease.