Aspirin (5 mmol/L) inhibits leukocyte attack and triggered reactive cell proliferation in a 3D human coronary in vitro model

Background-Leukocyte attack (LA) and the triggered reactive proliferation o f smooth muscle cells (SMCs) are key events for the development of early at herosclerosis and restenosis. In the present study, we used a 3D human coro nary in vitro model of LA (3DLA model) to examine the effect of high-dose a spirin on the adhesion and chemotaxis of leukocytes and the reactive prolif erative response of SMCs. Methods and Results-For dose-finding, the effect of aspirin (1, 2, 5, and 1 0 mmol/L) on the tumor necrosis factor-alpha -induced upregulation of inter cellular adhesion molecule-1 was analyzed in monocultures of human coronary endothelial cells (HCAEC) and the SMCs of the human coronary media (HCMSMC ). In cytoflow and Northern blot experiments, the expression of intercellul ar adhesion molecule-1 was slightly reduced after incubation with 5 mmol/L aspirin, and strong inhibition was found after incubation with 10 mmol/L. I n 3DLA models, HCAECs and HCMSMCs were cultured on both sides of a porous f ilter. For LA, human monocytes or CD4(+) lymphocytes were seeded on the KCA EC side of the 3DLA unit. A dose of 5 mmol/L aspirin inhibited the adherenc e of monocytes or CD4(+) lymphocytes by 50% (P<0.01) and the chemotaxis of monocytes by 90% (P<0.01). The reactive proliferative response of coculture d HCMSMCs after LA, as measured by the uptake of bromodeoxyuridine, was sig nificantly reduced by 83% after selective monocyte attack (P<0.001) and by 42% after selective CD4+ lymphocyte attack (P<0.05). Conclusions-A local concentration of 5 mmol/L aspirin should be accepted as the lowest rational concentration for the beneficial in vitro effects of h igh-dose aspirin to be reproduced in clinical studies.