Background: Endothelins are important vasoconstrictors and cellular-growth promoters. ETA-specific antagonists have been shown to reduce neointimal response to injury in some experimental angioplasty models. However, there is little information on the effects of dual ETA/ETB receptor blockers, such as bosentan, on neointimal proliferation following experimental coronary angioplasty.
Materials and methods: Coronary injury was achieved by directional atherectomy in the left anterior descending artery of 20 pigs. Animals were randomly assigned to receive a daily dose of oral bosentan (30 mg kg-1) (group I, n = 10) or no treatment (group II, n = 10). At 4 weeks, arteries were processed for histomorphometry and endothelin characterization.
Results: Vessel injury score was similar among the two groups. Overall, a linear correlation was found between injury and neointimal development (r = 0.57, P = 0.01). This correlation had a lower slope in group I compared with group II (P < 0.001), indicating a smaller amount of neointimal development for a similar degree of injury in bosentan-treated animals. Multivariate regression showed that neointimal response was reduced by oral treatment with bosentan (beta: -0.59 mm2, 95% CI: -1.11/-0.06 mm2). In addition, immunostaining revealed fewer positive endothelin areas in group I arteries.
Conclusions: Oral treatment with bosentan reduces neointimal development following coronary angioplasty in this experimental model.