The effect of raloxifene on coronary arteries in aged ovariectomized ewes

Background - Ovariectomized sheep are a useful model of postmenopausal oste oporosis and other postmenopausal conditions. Estrogen may have a protectiv e effect on the coronary arteries in postmenopausal women. The effects of r aloxifene, a selective estrogen receptor modulator, on coronary arteries in aged ovariectomized ewes was investigated. Methods and Results - Forty eight aged ewes were randomly assigned to under go sham surgery (Sham, n = 7), ovariectomy (OVX, n = 10), ovariectomy with estradiol supplementation (OVXE, n = 8), ovariectomy with raloxifene supple mentation, 0.02 mg/kg per day (RAL1, n = 10), or ovariectomy with raloxifen e supplementation, 0.10 mg/kg per day (RAL2, n = 13), Contrast coronary ang iography was performed 6 months after intervention. Diameters of the right main and left anterior descending coronary arteries in the RAL1, RAL2, and Sham groups were not different from each other, but were significantly grea ter than the OVX and OVXE groups. Intracoronary nitroglycerin did not affec t the relationships of the diameters in any group. There were no difference s in vascular remodeling between the groups. Conclusions - The results indicate that raloxifene in this sheep model allo ws greater dilation of coronary arteries than estrogen, Raloxifene may prov ide a significant protective functional effect on coronary arteries in post menopausal heart disease.