Cardiovascular Effects of Raloxifene Hydrochloride

Raloxifene hydrochloride binds to the estrogen receptor and shows tissue‐selective effects; thus, it belongs to a class of drugs recently described as selective estrogen receptor modulators (SERMs). Tissue selectivity of raloxifene may be achieved through several mechanisms: the ligand structure, interaction of the ligand with different receptor subtypes in various tissues, and intracellular events after ligand binding. Raloxifene has estrogen‐agonist effects on bone and lipids and estrogen antagonist effects on the breast and uterus. In addition to its well established effects on osteoporosis, recent preclinical and clinical findings suggest that raloxifene also possesses beneficial effects on the cardiovascular system. These findings indicated that raloxifene may have cardioprotective properties without an increased risk of cancer or other side effects. Raloxifene has been shown to reduce total and low‐density lipoprotein cholesterol concentrations in plasma, an effect similar to that produced by estrogens. Unlike estrogens, however, raloxifene does not increase high‐density lipoprotein cholesterol and triglyceride levels in plasma. Endothelium is thought to play an important role in the genesis of atherosclerosis. Several lines of evidence suggest that an intervention with endothelial function might influence the progression of coronary disease and the incidence of cardiovascular events. Raloxifene increases the nitric oxide/endothelin‐1 ratio, and improves endothelium‐dependent vasomotion in post‐menopausal women to the same extent as estrogens. Furthermore, in two randomized trials on post‐menopausal women raloxifene reduced homocysteine levels, another independent risk factor for the development of cardiovascular disease. Although estrogens remain the drugs of choice in the hormonal therapy of most postmenopausal women, raloxifene may represent an alternative in women who are at risk of coronary artery disease.     

Evaluation of the sexual function and quality of life in raloxifene treated postmenopausal women

Objective  To evaluate the net effect of raloxifene on overall quality of life and sexual function in postmenopausal women. Methods  The study was performed in the Gynecology and Obstetrics outpatient clinic of Gazi University Faculty of Medicine between January 2002 and February 2005. Fifty postmenopausal women, in whom raloxifene was indicated for prevention and treatment of osteoporosis, were considered the study group. Fifty postmenopausal women who were not osteoporotic were enrolled as the control group. Participants completed a questionnaire composed of several parts (GRISS, BDI and ISI), at the beginning and end of the 12-month treatment period. Results  Two groups were similar to each other with respect to total GRISS scores at the beginning and at the end of the study (P = 0.929 and P = 0.508; respectively). Raloxifene was associated with a significant improvement from baseline in the total scores of BDI (P = 0.0001), whereas this improvement was not significantly different from the control group (P = 0.216). With regard to ISI scores, there were no differences between groups in total scores. Raloxifene use did not seem to affect subscores of ISI either. Conclusions  This study failed to prove any deleterious effect of raloxifene on quality of life and sexual functions.     

Time-dependent changes in biochemical bone markers and serum cholesterol in ovariectomized rats: Effects of raloxifene HCl, tamoxifen, estrogen, and alendronate

Bone loss associated with postmenopausal osteoporosis can be reduced by treatment with antiresorptive agents such as estrogen or bisphosphonates. Whereas bisphosphonates primarily affect bone loss, estrogens have an advantage of also lowering serum cholesterol levels, although they have a detrimental effect in the uterus. Recently, raloxifene HCl, a selective estrogen receptor modulator (SERM), has been shown to decrease both bone loss and cholesterol levels without the negative uterine effects. These antiresorptive agents reduce bone turnover, which can be evaluated by measuring bone turnover markers. To compare the effects of estrogen, two SERMs (raloxifene HCl and tamoxifen), and alendronate, a bisphosphonate that inhibits bone loss by an estrogen-independent pathway, on metabolic bone markers and cholesterol levels, rats were ovariectomized 2 weeks prior to 3 weeks of daily oral treatment with raloxifene HCl (3 mg/kg), ethynyl estradiol (0.1 mg/kg), tamoxifen (3 mg/kg), or alendronate (3 mg/kg). Raloxifene HCl, tamoxifen, and ethynyl estradiol reduced serum cholesterol to levels below control values within 4 days after initiation of treatment, whereas alendronate had no effect. After 3 weeks of treatment, serum cholesterol values in ethynyl estradiol treated animals, although still below the control value, had risen 6.4-fold; raloxifene HCl and tamoxifen values rose by only 1.4–1.5-fold. Therefore, compared with estrogen, SERMs may have a longer-term suppressive effect on serum cholesterol. At 4 days of treatment, ovariectomized rats had a 1.4-fold increase in serum osteocalcin level compared with controls. Ethynyl estradiol lowered this level within 1 week of treatment by 18%, with a more pronounced reduction of 34% at 3 weeks. In contrast, raloxifene HCl, tamoxifen, or alendronate had very little effect after the first week (6% to 13% reduction), although there was an 18% to 25% reduction by 3 weeks. Urinary pyridinoline levels, elevated 1.4-fold in the ovariectomized rat compared with controls 2 weeks after surgery, were reduced to control values after 2 weeks of treatment with raloxifene HCl, ethynyl estradiol, tamoxifen, or alendronate. These data support the concept that estrogen, raloxifene HCI, tamoxifen, and alendronate inhibit bone loss in the ovariectomized animal by reducing bone resorption. The results also indicate that for treatment of postmenopausal osteoporosis, raloxifene HCl may have an advantage over the other antiresorptives studied in having both non-uterotrophic and hypocholesterolemic effects in addition to its ability to inhibit bone resorption.     

雷诺昔芬对人卵巢癌细胞株SKOV3体外生长的影响

目的　探讨雷诺昔芬对人卵巢癌细胞株体外生长和细胞增殖抗原Ki 67表达的影响。　方法　四甲基偶氮唑蓝 (MTT)比色法观察卵巢癌细胞株SKOV3在加入不同浓度的雷诺昔芬培养液后细胞的生长情况 ;免疫组织化学方法测定癌细胞在加入雷诺昔芬后细胞增殖抗原Ki 67的表达情况。　结果　高浓度雷诺昔芬对卵巢癌细胞株呈抑制作用 ,而低浓度则初期促进细胞生长 ,随之呈抑制细胞生长的趋势 ;高浓度雷诺昔芬不仅降低Ki 67抗原的表达 ,还破坏细胞结构。　结论　雷诺昔芬对人卵巢癌细胞株SKOV3无明显的刺激生长作用     

Chitosan-Raloxifene nanoparticle containing doxorubicin as a new double-effect targeting vehicle for breast cancer therapy

Backgroundtreatment of breast cancer as one of the most common cancers in the world remains an important area of drug development based on nanoparticulate systems. Effective targeted therapy of affected cells based on ligand conjugate biocompatible polymeric nanoparticles is an attractive perspective in this context.ObjectiveIn this study, a novel double effect nanoparticle based on Chitosan-Raloxifene conjugate was prepared for adjuvant therapy (hormone and chemo therapy) and drug targeting to breast cancer cells via estrogen receptor (ER).MethodsChitosan-raloxifene conjugate was synthesized. Related nanoparticles containing doxorubicin (DOX) were prepared and characterized. Experimental design study was performed to determine the optimum levels of variables in the preparation of nanoparticle. Drug loading, release, nanoparticle stability, and the effect of nanoparticles on cell viability were evaluated. Further, inhibition tests were performed to demonstrate that the function of these novel nanoparticles is mediated via ER.ResultsChitosan-raloxifene conjugate was successfully synthesized. The prepared nanoparticles showed sizes within 25–35 nm, more than 95% drug loading, about 60% of drug release and desired stability after 24 h. XTT assay on MCF-7 cell line illustrated that these nanoparticles could inhibit the cellular growth up to 60%. The results from inhibition tests revealed that prepared nanoparticles can inhibit cell growth via ER blocking.ConclusionThis study introduced chitosan-raloxifene nanoparticles containing doxorubicin as a novel targeting agent for adjuvant therapy of breast cancer. Open in a separate windowGraphical abstractElectronic supplementary materialThe online version of this article (10.1007/s40199-020-00338-9) contains supplementary material, which is available to authorized users.     

Activity of three selective estrogen receptor modulators on hormone-dependent responses in the mouse uterus and mammary gland

Selective estrogen receptor modulators (SERMs) have the unique potential to provide estrogenic effects in the skeletal and cardiovascular system, while minimizing/eliminating side effects on reproductive organs. However, despite the unifying characteristic of mixed estrogen receptor (ER) agonist/antagonist activity, compounds within this class are not interchangeable. In order to define and compare the effects of SERMs on different hormone-responsive tissues, we evaluated effects of bazedoxifene acetate (BZA), lasofoxifene (LAS) and raloxifene (RAL) in the mammary gland and uterus of the ovariectomized mouse. Endpoints measured included those regulated by estradiol alone (uterine wet weight, uterine G protein-coupled receptor 105 (GPR105) mRNA expression and mammary gland indoleamine-pyrrole 2,3 dioxygenase (INDO) mRNA expression) as well as others that required the combination of estradiol and progesterone (uterine serine protease inhibitor Kazal type 3 (Spink3) mRNA expression, mammary gland morphology and mammary gland defensin beta1 (Defbeta1) mRNA expression). The three SERMs tested had variable agonist and antagonist activity on these endpoints. In the uterus, the SERMs were mixed agonists/antagonists on estradiol-induced wet weight increase, whereas all three SERMs were estrogen receptor antagonists on GPR105 mRNA expression. However, in the presence of progesterone, BZA and RAL were agonists on Spink3 expression, while LAS was primarily an antagonist. In the mammary gland, BZA and RAL were predominantly agonists on the endpoint of mammary morphology and all three SERMs were clear agonists on Defbeta1 mRNA expression, an E+P-dependent marker. Finally, LAS and RAL had mixed agonist/antagonist activity on INDO mRNA expression, while BZA had only antagonist activity. These results demonstrate that compounds with small structural differences can elicit distinct biological responses, and that in general, SERMs tended to behave more as antagonists on endpoints requiring estrogen alone and agonists on endpoints requiring the combination of estrogen and progesterone.     

雷洛昔芬对小鼠成骨细胞中护骨素核因子-κB受体活化因子配体表达的影响

目的 雷洛昔芬对小鼠成骨细胞中护骨素(OPG)、核因子-κB(NF-κB)受体活化因子配体(RANKL)表达的影响. 方法 取出生24 h内的小鼠30只,无菌的条件下取出颅骨,应用酶消化法进行成骨细胞的培养,在培养成骨细胞的培养液中加入不同浓度的雷洛昔芬(0、1012、1010、109mol/L),应用反转录聚合酶链扩增(RT-PCR)法检测其对OPG/RANKL mRNA的表达及酶联免疫吸附法(ELISA)法检测OPG蛋白分泌的影响. 结果 OPG mRNA在实验组中表达较对照组强,并且不同浓度组间的比较,差异有统计学意义(均为P<0.05),1010.mol/L组较10～mol/L、1012mol/L组的表达明显增强;RANKL mRNA在实验组的表达均较对照组弱,其组间的差异亦有统计学意义(P<0.01).并且随着雷洛营芬浓度的增加,RANKL mRNA的表达明显减弱,呈现明显的浓度依赖性.在试验组小鼠成骨细胞培养液中OPG浓度(10-9mol/L组为3.017±0.459,1010mol/L组为3.981±0.762,1012mol/L组为2.864±0.416)较对照组(2.106±0.316)增高,差异有统计学意义(P<0.05). 结论 雷洛昔芬能促进成骨细胞的中OPG的mRNA的表达及其蛋白的分泌,同时抑制RANKL的mRNA的表达.