A comparison of the anti-inflammatory activities of conjugated estrogens and 17-β estradiol

Abstract

Objective and design: Unregulated chronic inflammatory process partly due to an estrogen deficiency may render postmenopausal women vulnerable to degenerative conditions such as arthritis, osteoporosis, atherosclerosis, and Alzheimer’s disease. Current confusion regarding therapeutic efficacy of estrogen replacement therapy may be due to different estrogen formulations used, short term therapy, as well as advanced stage of the disease.

Materials and methods: We compared anti-inflammatory activities of two major estrogen preparations, conjugated equine estrogen (CEE) and 17-β estradiol, using an animal model (rat mesentery) of in vivo inflammatory reaction to intravenously infused amyloid-β, examined by video recording and subsequently analyzed by transmission electron microscopy. Cellular markers of inflammation were monitored: leukocyte migration, platelet activation, mast cell activation/degranulation, and endothelial disruption.

Results: Low doses of CEE (0.3 mg/kg for 3 weeks) demonstrated significant anti-inflammatory activity, whereas even at high doses (2.0 mg) 17-β estradiol had only minimal activity.

Conclusion: CEE, a mixture of several compounds, may have some component(s) with significant anti-inflammatory activity. The anti-inflammatory activity of CEE may have a role in prevention of several degenerative diseases associated with menopause.