Inhibitory effect of agmatine on monocyte/endothelial cell adhesion

Objective To investigate the effect of endogenous agmatine on monocyte/endothelial cell adhesion induced by oxidized low density lipoprotein (ox-LDL) and to elucidate the mechanism. Methods Human umbilical vein endothelial cells (HUVECs) were cultured and identified, then divided into four groups: AGM group in which the HUVECs were cultured in serum-free culture fluid containing 10 -8 , 10 -7 , 10 -6 , 10 -5 , 10 -4 , 10 -3 mol/L AGM for 20 h, then with addition of 100 mg/L ox-LDL for 4 h; L-NAME+AGM group in which only N G -Nitro-L-Arginine Methyl Ester (L-NAME)—NOS depressor was added 30 min before the process of AGM group; ox-LDL group in which the HUVECs were cultured in serum-free culture fluid for 20 h, then with the addition of ox-LDL for 4 h; control group in which the HUVECs were cultured only in serum-free culture fluid. Monocytes were isolated from peripheral blood. Then the ICAM-1 expression was detected by immunocytochemistry and monocytes adhesion was detected. Results Agmatine significantly inhibited the adhesion of monocytes to HUVECs and the expression of ICAM-1 induced by ox-LDL in a dose dependent manner (P0.01). The ICAM-1 expression was positively correlated with the monocytes adhesion (r= 0.885 7 , P0.001), and this effect was attenuated by L-NAME (P0.05). Conclusion AGM is a potent in vivo inhibitor of monocyte/endothelial cells adhesion. The effect could be ICAM-1-dependent and correlated with nitric oxide synthase.