Genistein aglycone, a soy-derived isoflavone, improves skin changes induced by ovariectomy in rats

BACKGROUND AND PURPOSE

Ovariectomy accelerates age-related skin changes as adequate oestrogen levels are required to control structural integrity and functional capacity of skin. Genistein, a soy-derived isoflavone, has been tested in anti-ageing cosmetic preparations with interesting results on skin elasticity, photoaging and skin cancer prevention. We investigated the effects of genistein aglycone and compared them with systemic raloxifene hydrochloride and 17-α-ethinyloestradiol on skin changes in aged, ovariectomized (OVX) rats.

EXPERIMENTAL APPROACH

Six months after ovariectomy, rats were randomly allocated to different groups and treated, daily, with genistein aglycone (1 and 10 mg·kg⁻¹ s.c.), raloxifene hydrochloride (0.05 and 0.5 mg·kg⁻¹ s.c.) or 17-α-ethinyloestradiol (0.003 and 0.03 mg·kg⁻¹ s.c.) for 12 weeks. Controls were untreated OVX and sham OVX rats. At the end of the treatment period, a skin biopsy was carried out and skin samples were assessed for molecular, histological and functional changes.

KEY RESULTS

Skin samples of untreated OVX rats showed a decrease in TGF-β1, VEGF, MMP-2, MMP-9, tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 compared with sham OVX rats. All the treatments significantly restored this depressed molecular profile revealed in OVX rats. Genistein aglycone, 1 mg·kg⁻¹, also significantly increased the thickness of collagen and breaking strength of skin in the OVX rats.

CONCLUSIONS AND IMPLICATIONS

Relatively long-term, systemic treatment with genistein aglycone shows comparable efficacy to oestrogen in reversing some molecular, histological and functional changes of the skin associated with ovariectomy in aged rats. This suggests that genistein aglycone might be an effective alternative therapy for the management of age-related skin changes in postmenopausal women.     

雷洛昔芬对放疗去势大鼠骨丢失的保护作用

目的:观察雷洛昔芬(选择性雌激素受体调节剂)对放疗去势大鼠的骨代谢生化指标、骨密度及骨形态学的影响,探讨其对放疗所致卵巢早衰引起骨丢失的保护作用。方法:选用3月龄雌性Wistar大鼠40只,随机分为4组:假放疗组、放疗组、放疗+雷洛昔芬组、放疗+己烯雌酚组,每组10只,16周后,腹主动脉取血,检测血清雌二醇、卵泡刺激素、骨钙素及碱性磷酸酶的水平;处死大鼠,取大鼠右侧股骨,测定各组骨密度;同时取左侧股骨制作骨切片行HE染色,观察骨形态学变化。结果:放疗组及放疗+雷洛昔芬组的雌二醇水平明显低于假放疗组及放疗+己烯雌酚组(P<0.05);而两组的卵泡刺激素水平明显高于假放疗组及放疗+己烯雌酚组(P<0.05);放疗组骨钙素和碱性磷酸酶明显高于其他3组,而另3组无明显差异(P>0.05);放疗组大鼠骨密度显著低于其他3组,其骨小梁稀疏,部分断裂,而另3组骨小梁致密,无明显断裂。结论:大鼠卵巢放疗可致去势,放疗去势后大鼠有骨质丢失发生,而选择性雌激素受体调节剂雷洛昔芬对放疗去势后大鼠的骨丢失有保护作用。     

Selective estrogen receptor modulators in clinical practice: a safety overview

Introduction: Selective estrogen receptor (ER) modulators (SERMs) are a class of nonsteroidal compounds that interact with ERs, each with a distinct tissue-specific profile. Depending upon the degree of ER agonism/antagonism at the target tissue, SERMs show efficacy for various indications including osteoporosis, dyspareunia, and breast cancer, and are associated with safety risks.

Areas covered: This review describes the safety profile of SERMs (tamoxifen, raloxifene, toremifene, bazedoxifene, lasofoxifene, and ospemifene) and fulvestrant (a pure ER antagonist) from Phase III trials, long-term extension studies, and active comparator studies. Tamoxifen, a first-generation SERM, is indicated for breast cancer prevention and treatment but is associated with serious safety concerns including endometrial cancer, venous thromboembolic events (VTE), and stroke. Toremifene, raloxifene, bazedoxifene, lasofoxifene, and ospemifene present generally improved, though distinctly different, safety profiles compared with tamoxifen, especially with endometrial cancer and stroke. However, the risk of VTE remains a concern for most SERMs.

Expert opinion: Each SERM presents a unique risk/benefit profile based on varying indications and tissue-specific ER agonist and antagonist effects, making careful patient selection and ongoing patient monitoring crucial aspects of treatment. Future research may focus on identifying new SERMs for endocrine-resistant and endocrine-responsive cancers and post-menopausal symptoms.     

Effects of phytoestrogens on DNA synthesis and creatine kinase activity in vascular cells

BACKGROUND: The aim of this study was to assess the effect of phytoestrogens on the human vascular wall in vitro. METHODS: We compared the effects of E2 to those of genistein (G), daidzein (D), biochanin A (BA), equol (EQ), and quecertin (Qu) on 3[H] thymidine incorporation and creatine phosphokinase (CK) activity in human vascular smooth muscle cells (VSMC) and in a human endothelial cell line (E304). RESULTS: In VSMC, E2, the estrogen antagonist raloxifene (RAL), G, and D stimulated DNA synthesis at low concentrations and suppressed 3[H] thymidine incorporation at higher concentrations. In contrast, BA and EQ had a monophasic stimulatory effect on 3[H] thymidine incorporation (87% +/- 9% and 54% +/- 17%, respectively) whereas Qu had only an inhibitory effect (-36 +/- 16% at 30 nmol/L). In E304 cells, all phytoestrogens stimulated DNA synthesis in a dose-related manner. In both cell types E2, RAL as well as all phytoestrogens increased CK-specific activity. The administration of phytoestrogens to immature female rats resulted in increased CK in the aorta (Ao) (60% to 220%) and in the left ventricle of the heart (Lv) (45% to 160%). Similar increases in Ao and Lv CK were also induced by E2 and all five phytoestrogens in ovariectomized (OVX) female rats. RAL antagonized phytoestrogen-induced CK activity in human vascular cells and in the rat Ao and Lv tissue but did not block phytoestrogen effects on DNA synthesis in human VSMC. CONCLUSIONS: Although phytoestrogens have estrogen-mimetic effects on cell growth and CK in cultured human vascular cells and on CK in rat vascular tissues in vivo, the effects on human VSMC replication are highly dependent on the concentration and the particular phytoestrogen under investigation.     

Effects of oestrogen agonists on human dermal fibroblasts in an in vitro wounding assay

Abstract:  Oestrogen and dehydroepiandrosterone (DHEA) improve wound healing, but circulating levels decline significantly with age. Recently, the selective oestrogen receptor modulators (SERMs) tamoxifen and raloxifene have been shown to improve age-associated impaired wound healing. Therefore, we have evaluated the effects of 17β-oestradiol, ERα and ERβ agonists, tamoxifen, raloxifene and DHEA on human dermal fibroblasts using an in vitro wound assay. An ERα agonist, 17β-oestradiol and DHEA all significantly accelerated cell migration; the DHEA effect was blocked with an aromatase inhibitor. Tamoxifen, raloxifene and DHEA all significantly increased DNA synthesis; the DHEA stimulatory effect was reversed by an aromatase inhibitor. This study demonstrates that 17β-oestradiol, an ERα agonist, tamoxifen, raloxifene and DHEA (following conversion to oestrogen) all have significant effects on human fibroblasts, the key mesenchymal cell involved in the wound healing process. Further understanding of the mechanisms involved may have important implications for the management of age-related impaired wound healing.     

Effect of raloxifene -- a selective oestrogen receptor modulator -- on kidney function in post-menopausal women with Type 2 diabetes: results from a randomized, placebo-controlled pilot trial.

AIMS: Epidemiological and experimental data suggest that activation of the oestrogen receptor pathway limits the incidence and the progression of diabetic nephropathy. We tested the hypothesis that raloxifene protects against increasing urinary albumin excretion in post-menopausal women with Type 2 diabetes in a randomized pilot clinical trial. METHODS: We included 39 post-menopausal women with Type 2 diabetes and micro- or macro-albuminuria in a 6-month, double-blind, placebo-controlled trial: 20 received placebo and 19 received 60 mg raloxifene per day. The albumin : creatinine ratio (ACR) in urine was determined on three consecutive days during the week before randomization and during the week before the final visit. RESULTS: One patient in each group dropped out in the first 3 weeks, leaving 37 patients for the analysis (19 on placebo and 18 on raloxifene). From randomization to the final visit, mean ACR was unchanged in the placebo group {277 microg/mg (67; 651) [median (interquartile range)] vs. 284 microg/mg (79; 1508)} but decreased slightly in the raloxifene group [376 microg/mg (67; 615) vs. 243 microg/mg (103; 549)]. This corresponds to a change of +24 (-37; +517) for the placebo group vs. -10 microg/mg (-36; +16) for the raloxifene group (P = 0.11). In multivariate analysis, raloxifene treatment (P(adjusted) = 0.013), baseline low-density lipoprotein (LDL) cholesterol (P(adjusted) = 0.023) and change in LDL cholesterol (P(adjusted) = 0.008) were related to the absolute change in ACR. Adverse effects were similar in the two groups. CONCLUSIONS: These results suggest that raloxifene may limit the progression of albuminuria in post-menopausal women with diabetes; further studies in a larger population are warranted.     

Current and emerging therapies in osteoporosis

Osteoporosis is a systemic skeletal disorder leading to decreased bone mineralisation and a propensity for fracture. The disease affects millions of people and is a source of significant morbidity and mortality. Fracture-related costs have skyrocketed in recent years and projections suggest an increase as the population ages. Recent advances in the understanding of bone biology have improved the therapeutic options for osteoporosis. This is a review of the osteoporotic therapies that have recently become available and a discussion of emerging options. An overview on current practice guidelines is provided.