Adhesion molecules in nonrheumatic aortic valve disease: endothelial expression, serum levels and effects of valve replacement

Abstract

We studied the expression of intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1) and endothelial selectin (E-selectin) on aortic valve endothelium in patients undergoing valve replacement. We also assessed the relation between serum levels and endothelial expression and also the changes in serum levels following surgery. Nonrheumatic aortic valve disease is believed to be a degenerative condition. Increased tissue and soluble adhesion molecule levels are described in inflammatory conditions. Aortic valves from 22 surgical (16 bicuspid, 6 tricuspid) and 6 autopsy (4 normal, 2 thickened) cases were studied by immunohistochemistry. Soluble adhesion molecules were measured in peripheral blood preoperatively, and at 6 and 18 months postoperatively, and compared with controls. The majority of the surgically removed tricuspid and bicuspid valves expressed adhesion molecules (E-selectin, 75% and 100%; ICAM-1, 75% and 80%; VCAM-1, 69% and 60%, respectively). The normal postmortem valves did not express these, while the diseased ones did. Endothelial expression of E-selectin correlated strongly with serum levels (r = 0.695, p = 0.004). Soluble E-selectin levels were significantly higher at baseline compared with controls (p = 0.017) and fell significantly at 18 months postoperatively (p = 0.005). Adhesion molecule expression on diseased valves supports an inflammatory component in "degenerative" aortic valve disease. The diseased valves may be the main source of elevated soluble E-selectin in this condition as blood levels correlate with endothelial expression and blood levels fall at 18 months postoperatively.