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Atherosclerosis and its most significant clinical repercussion, cardiovascular disease (CVD), is the leading cause of morbidity and mortality in postmenopausal women, with a substantial global public health impact as a consequence. Vascular endothelial dysfunction, which is potentiated by decreasing estrogen levels in the menopausal transition period, is an early hallmark of developing CVD. The action of estrogens has been widely investigated in many critical areas of atherogenesis, due to the presence of estrogen receptors in the vascular system. Estrogens can have both positive and negative effects on the vascular wall depending on the stage of atherosclerosis disease. The estrogen response is mediated by different mechanisms, involving either genomic pathways requiring ligand-activated transcription with posterior modulation of protein synthesis, or non-genomic pathways, mainly affecting enzyme activity and rapid signaling cascades.
The vigorous debate surrounding the risk/benefit profile of estrogen in the development and timing of CVD in postmenopausal women is still ongoing. Evidence that the progestin component of hormone therapy increases breast cancer risk or even attenuates the potential beneficial effects of estrogens has been paralleled by a decline in the use of hormone therapy in postmenopausal women in recent years. This data, along with problems associated with long-term use of bisphosphonates, has shifted the focus of recent research to other molecules capable of activating estrogen receptors, leading to transcriptional activity in some tissues but not in others. Selective estrogen receptor modulators (SERMs) and more recently, tissue selective estrogen complex (TSEC) have been developed as alternatives to hormonal replacement therapy (HRT).Previous experimental studies have shown the capacity of estrogens and second-generation SERM raloxifene to promote endothelial cell regrowth and improve cell survival rate in the early stages of atherosclerosis disease. Clinical trials involving bazedoxifene or conjugated estrogens plus bazedoxifene have shown cardiovascular safety in healthy postmenopausal women. However, one research group working with an atherosclerotic animal model in monkeys demonstrated that therapeutic application of bazedoxifene had no effect on atherosclerosis. What is more, bazedoxifene completely impeded the antiatherosclerotic effects of estrogen treatment in the mentioned study. To date no report has been published of bazedoxifene’s effect on vascular cell proliferation and the mechanisms involved using an in vitro model.Previous experimental studies have shown the capacity of estrogens and second-generation SERM raloxifene to promote endothelial cell regrowth and improve cell survival rate in the early stages of atherosclerosis disease. Clinical trials involving bazedoxifene or conjugated estrogens plus bazedoxifene have shown cardiovascular safety in healthy postmenopausal women. However, one research group working with an atherosclerotic animal model in monkeys demonstrated that therapeutic application of bazedoxifene had no effect on atherosclerosis. What is more, bazedoxifene completely impeded the antiatherosclerotic effects of estrogen treatment in the mentioned study. To date no report has been published of bazedoxifene’s effect on vascular cell proliferation and the mechanisms involved using an in vitro model.
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