Effects of raloxifene treatment on the phenotype of blood monocytes

Abstract

Raloxifene (RLX), a selective oestrogen receptor modulator, has oestrogen-agonist effects on bone, lipoproteins, and homocysteine and oestrogen-antagonist activity in the breast and uterus, positioning it as a potential drug for long-term prevention of coronary heart disease in postmenopausal women. To further evaluate its influence on cardiovascular risk factors, we studied the effects of 60 mg/day RLX on serum lipid levels, inflammatory (high-sensitivity C-reactive protein, and coagulation (fibrinogen) markers, monocytes, and fibrinolysis in 15 healthy postmenopausal women. Markers were measured at baseline, after 1 month without treatment, and after 3 months of treatment. Fibrinolysis was evaluated using the euglobulin clot lysis time (ECLT) determined with a new semiautomatic optical method. Monocyte phenotype was determined by measurement of the expression of the antigens CD14, HLA-DR, and CD62-L using flow cytometry. After 3 months of RLX treatment, we observed a decrease in total cholesterol (p = 0.002), in low-density lipoprotein cholesterol (p <0.001), and in lipoprotein A (p = 0.01). Fibrinogen (p = 0.002) decreased significantly, and high-sensitivity C-reactive protein had a tendency to decrease, but this did not reach statistical significance (p = 0.06). RLX treatment had no effect on ECLT (p = 0.223) or on white blood cell, lymphocyte, and total monocyte counts (p = 0.313). Monocyte expression of HLA-DR, CD14, and CD62-L was not modified by the treatment. In conclusion, we confirm that RLX has beneficial short-term effects on levels of lipids and inflammatory markers, with no effect on fibrinolysis or monocyte phenotype.