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 of smooth muscle cells (SMCs) are key events for the development of early atherosclerosis and restenosis. In the present study, we used a 3D human coronary in vitro model of LA (3DLA model) to examine the effect of high-dose aspirin on the adhesion and chemotaxis of leukocytes and the reactive proliferative response of SMCs. METHODS AND RESULTS For dose-finding, the effect of aspirin (1, 2, 5, and 10 mmol/L) on the tumor necrosis factor-alpha-induced upregulation of intercellular 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 intercellular adhesion molecule-1 was slightly reduced after incubation with 5 mmol/L aspirin, and strong inhibition was found after incubation with 10 mmol/L. In 3DLA models, HCAECs and HCMSMCs were cultured on both sides of a porous filter. For LA, human monocytes or CD4(+) lymphocytes were seeded on the HCAEC side of the 3DLA unit. A dose of 5 mmol/L aspirin inhibited the adherence 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 cocultured HCMSMCs after LA, as measured by the uptake of bromodeoxyuridine, was significantly 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 high-dose aspirin to be reproduced in clinical studies.