Abstract

We previously have described a quantitative angiogenesis in vitro model, in which endothelial cells are cultured between two layers of type I collagen gel and become organized into tube-like structures. Using this model, the effect of eicosapentaenoic acid (20:5n-3) on tube formation was investigated. When the endothelial cells isolated from bovine carotid artery were treated for 2 days with 5 micrograms/mL of arachidonic acid (20:4n-6), eicosapentaenoic acid or docosahexaenoic acid (22:6n-3), these polyunsaturated fatty acids were extensively incorporated into cellular phospholipids. The context of arachidonic, eicosapentaenoic and docosahexaenoic acid increased from 9.58% to 23.29%, from 0.98% to 11.76% and from 6.88% to 18.40%, respectively. When the eicosapentaenoic acid-treated cells were cultured between collagen gels, the tube-forming ability of the cell was markedly inhibited. The inhibition was dose-dependent between 1.0 and 5.0 micrograms/mL of eicosapentaenoic acid. At 5.0 micrograms/mL of eicosapentaenoic acid the inhibition reached 76%. By contrast, arachidonic acid increased tube formation, and docosahexaenoic acid had no effect. To elucidate the mechanism of eicosapentaenoic acid induced inhibition of in vitro tube formation, we examined the effect of the acid on the proliferation of endothelial cells. Eicosapentaenoic acid at any dose (less than 5.0 micrograms/mL) had no effect on the proliferation of endothelial cells cultured on plastic plates without collagen gel. However, when the cells were cultured between collagen gels, eicosapentaenoic acid inhibited cell growth in a dose-dependent manner with maximum inhibition being observed at 2.5 micrograms/mL. These data suggest that eicosapentaenoic acid suppresses tube formation of endothelial cells,at least in part, via its inhibitory effect on cellular proliferation.(ABSTRACT TRUNCATED AT 250 WORDS)