Expression of growth arrest-specific protein 6 and Axl molecules in the left internal mammary artery of patients undergoing coronary artery bypass grafting.

Studies have demonstrated that using a left internal mammary artery (LIMA) graft yields excellent long-term results in coronary artery bypass grafting (CABG). The growth arrest-specific 6 (Gas6) gene and its receptor, Axl, are crucial in vascular haemostasis and atherosclerosis. The objective of this study was to determine the expression of Gas6 and Axl molecules in the aorta and LIMA in patients undergoing CABG. Plasma and tissue specimens were collected from 19 patients undergoing elective CABG. The expression of the Gas6 and Axl in the injured aorta and LIMA was examined using reverse transcription PCR (RT-PCR), real-time RT-PCR, western blot and immunohistochemical staining. In CABG patients, the mRNA, immunoreactivity and protein expressions of the Gas6 and Axl were considerably higher in the LIMA than those in the aorta. Further analysis revealed that the expression of the Gas6 positively correlated with that of Axl in the LIMA and aorta. The plasma Gas6 level was considerably and positively correlated with the expression of Gas6 protein in the LIMA and aorta. The present study discovered that the higher expression of Gas6/Axl pathway components in the LIMA compared with that in the aorta may partly explain the less frequent atherosclerotic events involving the LIMA compared with other arteries. Moreover, Gas6 may play a critical and protective role in human vascular biology.