The effects of short-term raloxifene therapy on fibrinolysis markers: TAFI, tPA, and PAI-1

Abstract

Background. Markers of fibrinolysis, thrombin-activatable fibrinolysis inhibitor (TAFI), tissue-type plasminogen activator (tPA), and plasminogen activator inhibitor-1 (PAI-1) levels were studied for the evaluation of short-term effects of raloxifene administration in postmenopausal women. Methods. Thirty-nine postmenopausal women with osteopenia or osteoporosis were included in this prospective, controlled clinical study. Twenty-five women were given raloxifene hydrochloride (60 mg/day) plus calcium (500 mg/day). Age-matched controls (n = 14) were given only calcium. Plasma TAFI, tPA, and PAI-1 antigen levels were measured at baseline and after 3 months of treatment by commercially available ELISA kits. Variations of individuals were assessed by Wilcoxon's test. Relationship between those markers and demographic characteristics were investigated. Results. Three months of raloxifene treatment was associated with a significant decrease in the plasma TAFI antigen concentrations (16% change, P < 0.01), and a significant increase in tPA antigen concentrations (25% change, P < 0·05). A significant correlation was found between baseline TAFI antigen concentrations and the duration of amenorrhea (P < 0·05; r = 0·33). Conclusion. We suggest that the increased risk of venous thromboembolism due to raloxifene treatment may be related to increased tPA levels, but not TAFI levels.