Inhibition of cultured bovine aortic smooth muscle cell proliferation by colominic acid

Colominic acid (CA) is an alpha2,8-linked polymer of sialic acid, originally isolated from capsular Escherichia coli K1. Since inhibition of arterial smooth muscle cell hyperplasia is one of the effective strategies to prevent atherosclerosis, we investigated the effect of CA, purified as an alpha2,8-linked homopolymer of N-acetylneuraminic acid, on the proliferation of bovine aortic smooth muscle cells in culture. The results demonstrate that CA inhibits the proliferation of the cells without nonspecific cell damage. Sulfation did not modify the inhibitory effect of CA. Specifically, the inhibitory effect of sulfated CA was almost equal to that of CA in vascular smooth muscle cell proliferation. On the other hand, it was suggested that the inhibition of the proliferation by CA is in a degree similar to that by heparin but weaker than that by sodium/calcium-spirulans, known sulfated polysaccharides as the potent inhibitor of vascular smooth muscle cells. The present data suggest that CA with or without sulfate groups can be an origin of beneficial agents that prevents atherosclerosis through a moderate inhibition of arterial smooth muscle cell proliferation.