Bazedoxifene: a selective estrogen-receptor modulator

Effects of bazedoxifene on endometriosis in experimental animal models: A systematic review and meta-analysis

Endometriosis is a prevalent condition in women that causes pelvic pain and fertility issues due to the growth of endometrial tissue outside the uterus during menstrual cycles. Steroid hormones play a crucial role in the development and growth of endometriosis lesions; therefore, researchers have investigated several effective drugs that target hormones for treating this disease. One such drug is bazedoxifene, but despite several animal studies, there has yet to be a comprehensive evaluation of their combined results. A systematic search was conducted across several databases (Embase, PubMed, Scopus, and Web of Sciences) to identify studies investigating the effectiveness of bazedoxifene in animal models of endometriosis. Meta-analysis was performed using the size of endometriosis implants before and after drug administration in the case and control groups, along with the p-value of the associations. Begg's and Egger's tests were used to assess publication bias. This study included four eligible studies consisting of 45 endometrial animal models and 35 control subjects. The meta-analysis showed that bazedoxifene significantly reduced the size of endometriosis implants in animal models compared with the control group (odds ratio: 0.122, 95% confidence interval: 0.050-0.298, p<0.001). Detailed investigation determined that there was no significant heterogeneity between the studies (I2=38.81, and p-value of the Q test=0.179). However, according to Egger's test, the study showed publication bias (p=0.035). This study found that bazedoxifene is a promising treatment option for endometriosis in animal models. However, more research on animals and humans is required to confirm these results.

Novel Advances in the Role of Selective Estrogen Receptor Modulators in Hormonal Replacement Therapy: A Paradigm Shift

Estrogen is a key regulatory hormone in the functioning of a female reproductive system. Estrogen hormone regulates many complex physiological processes, which has its role in reproduction and skeletal and cardiovascular systems by acting on estrogen receptors alpha (ERα) and beta (ERβ), which are nuclear transcription factors. Selective estrogen receptor modulators (SERMs) are now being used to treat bone loss, breast carcinoma, and menopausal symptoms, metabolic neurodegenerative because of their characteristics that allow them to function as both estrogen agonists and antagonists, depending on the target tissue. First-generation SERMs, such as Tamoxifen, are used in the management protocol for breast cancer, which is estrogen receptor (ER-positive). Raloxifene is a second-generation SERM that is a valuable adjunct used to treat and prevent osteoporosis in postmenopausal women and prevent compression fractures of the vertebral column. Novel SERM molecules are on the horizon, proven more potent and efficacious in preventing and treating osteoporosis. These include Ospemifene, lasofoxifene, bazedoxifene and arzoxifene. The benefits of Raloxifene versus that of Bazedoxifene are under trial. Despite their therapeutic benefits and actions, these medications are not without adverse effects, such as thromboembolic disorders. Increased risk of uterine cancer has been linked to Tamoxifen. This article delves into the world of SERMs, including their development and discovery. The newer SERMs in late development, ospemifene, lasofoxifene, bazedoxifene, and arzoxifene, are described in detail.

Effects of the conjugated equine estrogen/bazedoxifene tissue-selective estrogen complex (TSEC) on mammary gland and breast cancer in mice

A tissue-selective estrogen complex (TSEC), combining a selective estrogen receptor modulator, bazedoxifene (BZA), with conjugated equine estrogen (CEE), represents a novel strategy of menopausal hormone therapy without involving a progestin. We hypothesized that the antiestrogenic properties of BZA can also block the estrogenic effects of CEE on breast tissue and thereby prevent breast cancer in women. To test our hypothesis, the effects of estradiol (E(2)), CEE, and BZA on mammary gland and breast cancer xenografts were assessed in mouse models. In immature castrate mice, BZA completely blocked CEE- or E(2)-stimulated ductal and terminal end bud growth of mammary gland as well as estrogen-responsive gene expression. As a positive control, E(2) stimulated tumor growth in nude mice bearing MCF-7 xenografts. This effect was completely blocked by BZA as were E(2)-stimulated expression of PR, pS2 (trefoil factor 1), cMyc, and AREG; the enhancement of Ki67 and proliferating cell nuclear antigen (PCNA); and the antiapoptotic effect. CEE was much less potent than E(2) in stimulating Ki67, reducing apoptosis, and stimulating gene expression, but all effects were blocked by BZA. Unexpectedly, CEE alone, even at high doses, did not stimulate tumor growth. As confirmation of its absorption and deconjugation, CEE caused a 6-fold increase in uterine weight and stimulation of gene expression. These data support our hypothesis that the net effect of the CEE/BZA TSEC is to block estrogen action in benign and malignant breast tissue. These findings provide a rationale for a clinical study to determine whether this TSEC prevents breast cancer in women.