phytoestrogens and Myocardial-Infarction

A recently (2002) published, randomised, double blind placebo controlled trial of hormone replace ment therapy (HRT), the Women's Health Initiative (WHI), is not consistent with the decrease in cardiovascular disease under CEE/HPA seen in observational primary prevention studies like the Nurses' Health Study. Baseline characteristics of participants like age, body mass index, years since menopause and preexistent cardiovascular diseases may be responsible for the lack of benefit seen in this trial. Clinical outcome data of HRT from randomised trials in secondary prevention of cardiovasular diseases are limited. The first prospective, randomised placebo controlled trial, the Heart and Estrogen/Progestin Replacement Study (HERS) in secondary prevention did not show any difference in CHD events between treatment groups and placebo during a follow up of 4.1 years. However, an increased risk of CHD was seen especially during the first year on HRT, subsequent years showed a decrease in event rate compared with never-users. One explanation for this lack of benefit may be a bi-directional effect of estrogen - early risk and late benefit - especially in an elderly study population with established atherosclerotic lesions. In postmenopausal women, estrogen replacement therapy affects LDL- and HDL-cholesterol levels favorably, causes vasodilatation by activating NOS, inhibits platelet aggregation and proinflammatory cell adhesion on endothelial cells of vascular wall. Estrogen can affect the cardiovascular system adversely by increasing triglycerid levels, CPR and proinflammatory cytokines like tumor necrosis factor alpha (TNF-alpha). Alternatives to HRT like phytoestrogens act via estrogen alpha and beta receptor modulation. Phytoestrogens may lower LDL-cholesterol levels without increasing triglyceride levels, they have shown antioxidannt properties as well as favorable effects on vascular reactivity. The importance of HRT and phytoestrogens in primary and secondary prevention of cardiovascular disease remains to be established.

Topics: Aged; Cardiovascular System; Coronary Disease; Double-Blind Method; Estrogen Replacement Therapy; Female; Follow-Up Studies; Humans; Middle Aged; Myocardial Infarction; Phytoestrogens; Randomized Controlled Trials as Topic; Risk Factors; Treatment Outcome

The data concerning post-menopausal hormone replacement therapy (HRT) were recently completely modified. The aim of this review is to present the last studies about post-menopausal HRT and to describe new alternatives to this treatment.. In May 2002, the women's health initiative (WHI) trial of post-menopausal HRT was interrupted earlier than expected. The studied hormonal formulation in this arm of the WHI trial was the association of conjugated equine estrogens and medroxyprogesterone. The reason for termination was an increased risk of breast cancer and myocardial infarction in the hormone-therapy group. Later, reports confirmed that this type of HRT could not be used any more for the primary prevention of coronary heart disease even if the absolute risk remained low. There is an increased risk for venous thromboembolism with post-menopausal estroprogestative replacement. This risk does not seem to exist with transdermal estrogens. The other WHI findings concerned the lack of protection against dementia and cognitive decline. On the contrary, osteoporotic hip fractures and colorectal cancers were reduced in the treated group. In April 2004, the estrogen only arm of the same WHI study was also prematurely interrupted because of an increase in the incidence of stroke. The risk of breast cancer was on the contrary not increased after 6.8 years, raising the question of the eventual role of progestins.. The impact of the WHI trial on clinical practice was very important since then. The "Agence Francaise de sécurité sanitaire des produits de santé" (AFSSAPS) edited in May 2004 a public recommendation limiting indication for HRT to patients with severe climacteric symptoms. The treatment must now be prescribed for the shortest time and at the minimal dose. The patient has to be precisely informed about the risks with HRT and the practitioner has to re-evaluate his prescription annually. Hormonal or non-hormonal alternatives have also to be considered as phytoestrogens and tibolone for hot flashes, and raloxifene and diphosphonates for osteoporosis prevention. In any case, a healthy diet, exercise and smoking cessation should be encouraged.

Topics: Breast Neoplasms; Clinical Trials as Topic; Equilin; Estrogen Replacement Therapy; Female; Hot Flashes; Humans; Life Style; Medroxyprogesterone; Menopause; Myocardial Infarction; Phytoestrogens; Risk Assessment; Thromboembolism; Treatment Outcome

Ischemic heart disease is the leading cause of death in postmenopausal women. The expression of caveolin, a membrane protein and a negative regulator of nitric oxide (NO), increases after menopause. The present study was designed to determine the effect of daidzein (DDZ), a phytoestrogen in attenuated cardioprotective effect of ischemic preconditioning (IPC) in ovariectomized rat heart.. Heart was isolated from ovariectomized rat and mounted on Langendorff's apparatus, subjected to 30 min ischemia and 120 min reperfusion. IPC was mediated by four cycles of 5 min ischemia and 5 min reperfusion. The infarct size was estimated using triphenyltetrazolium chloride stain, and coronary effluent was analyzed for lactate dehydrogenase and creatine kinase MB (CK-MB) release to assess the degree of myocardial injury. The release of NO was estimated indirectly by measuring the release of nitrite in coronary effluent.. IPC-induced cardioprotection was significantly attenuated in ovariectomized rats as compared to normal rats, which was restored by treatment of DDZ, a caveolin inhibitor (0.2 mg/kg subcutaneously) for 1 week. However, this observed cardioprotection was significantly attenuated by perfusion of l-nitroarginine methyl ester, an endothelial nitric oxide synthase (eNOS) inhibitor (100 µM/L) and glibenclamide, an adenosine triphosphate-sensitive potassium ion channel blocker (10 µM/L) alone or in combination, noted in terms of increase in myocardial infarct size, release of LDH and CK-MB, and also decrease in the release of NO.. Thus, it is suggested that DDZ restores the attenuated cardioprotective effect in ovariectomized rat heart, which may be due to downregulation of caveolin and subsequent increase in the activity of eNOS.

Topics: Animals; Caveolin 1; Creatine Kinase, MB Form; Disease Models, Animal; Female; Heart; In Vitro Techniques; Ischemic Preconditioning, Myocardial; Isoflavones; L-Lactate Dehydrogenase; Myocardial Infarction; Nitrites; Ovariectomy; Phytoestrogens; Rats, Wistar

It has been previously reported that oral or intra-peritoneal administration of tanshinone IIA can alleviate the ventricular hypertrophy and fibrosis that develops in rats after experimental cardiac infarction. Our present studies, performed on cultures of human cardiac fibroblasts, investigated the mechanism by which tanshinone IIA produces these beneficial effects. We found that treatment of cardiac fibroblasts with 0.1-10µM tanshinone IIA significantly inhibited their deposition of collagen I, while enhancing production of new elastic fibers. Moreover, both anti-collagenogenic and pro-elastogenic effects of tanshinone IIA occurred only after selective activation of the G protein-coupled estrogen receptor (GPER). This subsequently leads to initiation of the PKA/CREB phosphorylation pathway that inversely modulated transcription of collagen I and elastin genes. Interestingly, treatment of human cardiac fibroblasts with tanshinone IIA additionally up-regulated the production of the 67-kDa elastin binding protein, which facilitates tropoelastin secretion, and increased synthesis of lysyl oxidase, catalyzing cross-linkings of tropoelastin. Moreover, tanshinone IIA also caused up-regulation in the synthesis of collagenolytic MMP-1, but down-regulated levels of elastolytic MMP-2 and MMP-9. In summary, our data validate a novel mechanism in which tanshinone IIA, interacting with a non-classic estrogen receptor, maintains the proper balance between the net deposition of collagen and elastin, allowing for optimal durability and resiliency of the newly deposited matrix.

Topics: Abietanes; Anti-Inflammatory Agents, Non-Steroidal; Cell Line; Collagen Type I; Cyclic AMP Response Element-Binding Protein; Cyclic AMP-Dependent Protein Kinases; Down-Regulation; Elastic Tissue; Elastin; Enzyme Activation; Extracellular Matrix; Humans; Matrix Metalloproteinase 1; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Myocardial Infarction; Myocardium; Myocytes, Cardiac; Phosphorylation; Phytoestrogens; Protein Binding; Protein-Lysine 6-Oxidase; Receptors, Estrogen; Receptors, G-Protein-Coupled; Tropoelastin; Up-Regulation

Cardiovascular disease is the leading cause of death among menopausal women in developed countries, mostly due to the loss of endogenous oestrogen protection. Soybean protein (SP) is rich in isoflavone phytoestrogens. This study aimed to determine the effect of SP on ovariectomised rats subjected to myocardial infarction and its possible cardio-protection.. The study was conducted on 30 adult female albino rats, which were divided into three groups: Group I comprised the sham-operated rats; Group II, the ovariectomised (OVX) rats fed a standard diet; and Group III, OVX rats fed a standard diet supplemented with SP (OVX plus SP). The rats were anaesthetised, and electrocardiograms were conducted. The rats were then sacrificed, after which their hearts and livers were removed, weighed and subjected to histopathological examination. Blood was collected to determine the lipid profile, and the levels of total triiodothyronine, tetraiodothyronine (T4), thyroid-stimulating hormone (TSH), creatinine phosphokinase (CPK), lactate dehydrogenase, superoxide dismutase (SOD) and malonedialdehyde (MDA).. The biochemical studies showed a significant increase in plasma CPK (Group II), MDA and triacylglycerol (Groups II and III) levels compared to Group I. The plasma SOD showed a significant decrease in Group II compared to Group I. Total cholesterol, low and very low density lipoprotein cholesterol levels showed a significant increase in Group II, and a significant decrease compared to Group I. Significant increases in T4 and TSH were found in Group III compared to Group II.. SP intake can be valuable in protecting the heart against an attack of acute myocardial infarction.

Topics: Animals; Body Weight; Cardiotonic Agents; Cardiovascular Diseases; Cholesterol, LDL; Cholesterol, VLDL; Electrocardiography; Female; Lipids; Myocardial Infarction; Ovariectomy; Phytoestrogens; Rats; Soybean Proteins; Triglycerides

We tested if endothelial function and estrogen receptor (ER) expression differs between resistance arteries in subcutaneous circulation from postmenopausal women with coronary heart disease (CHD, congruent with 1 year after myocardial infarction, n=12) and aged matched controls (n=14); and if acute effects of phytoestrogens (genistein, resveratrol) could be of relevance for vascular protection. We utilized ex vivo small artery ( congruent with 350 microm) bioassays and found no difference in bradykinin (BK)-mediated dilatation between the groups. One-hour incubation with phytoestrogens (natural ER beta agonists), propyl-pyrazole-triol-trisphenol (PPT-selective ER alpha agonist) and 17beta-estradiol (17beta-E(2)-ER alpha/beta agonist) at 0.01 microM/L had no effect on BK-induced responses. Concentration-response curves (0.01-30 microM/L) to investigated compounds were also obtained and compared in separate arteries. We found that dilatation to phytoestrogens was enhanced in CHD if compared to controls (p<0.05), while responses to 17beta-E(2) remained similar. The dilatation to phytoestrogens was also higher if compared to 17beta-E(2) (p<0.05) in CHD. In controls, only responses to PPT, but not to phytoestrogens, were enhanced in comparison to 17beta-E(2) (p<0.05). Inhibition of NO synthase had no effect on dilatation induced by increasing concentrations of investigated compounds. ER beta expression was enhanced in the vascular wall from CHD women, while ER alpha predominated in the controls (p<0.05). We suggest that diet supplementation by phytoestrogens may provide cardiovascular benefit for postmenopausal women with CHD. The selective targeting of one of the ER subtype may have implications for women's cardiovascular health.

Topics: Aged; Arteries; Case-Control Studies; Endothelium, Vascular; Estradiol; Estrogen Receptor alpha; Estrogen Receptor beta; Female; Genistein; Humans; Middle Aged; Myocardial Infarction; Phenols; Phytoestrogens; Postmenopause; Pyrazoles; Resveratrol; Stilbenes; Subcutaneous Fat, Abdominal; Vasodilation; Vasodilator Agents

Estrogens are known to activate the phosphatidyl-inosityl 3-kinase (PI3K)/Akt pathway, which is central in the cardioprotection afforded by ischemic postconditioning. Therefore, our goal was to investigate whether a phytoestrogen, genistein, could induce a pharmacological postconditioning and to investigate potential mechanisms. We used low doses of genistein in order to avoid tyrosine kinases inhibition. Thus, pentobarbital-anesthetized rabbits underwent a coronary artery occlusion followed by 4 h of reperfusion. Prior to reperfusion, they randomly received an i.v. injection of either saline (Control), 100 or 1000 microg/kg of genistein (Geni(100) and Geni(1000), respectively), and 10 or 100 microg/kg of 17beta-estradiol (17beta(10) and 17beta(100), respectively). Infarct size (IS, % area at risk) was significantly reduced in Gen(100), Gen(1000) and 17beta(100) but not in 17beta(10) (6+/-2, 16+/-5, 12+/-3 and 29+/-7%, respectively) vs. Control (35+/-4%). A significant decrease in the percentage of TUNEL-positive nuclei within infarcted area was observed in Gen(100) and 17beta(100) vs. Controls. The estrogen receptor antagonist fulvestrant (1 mg/kg i.v.) and the PI3K inhibitor wortmaninn (0.6 mg/kg) abolished the cardioprotective effect of genistein. Western blots also demonstrated an increase in Akt posphorylation in Gen(100). In the same group, in vitro mitochondrial swelling studies demonstrated a significant inhibition of calcium-induced opening of mitochondrial transition pore vs. Controls. In conclusion, genistein exerts pharmacological postconditioning with a similar potency as 17beta-estradiol through a pathway involving activation of the estrogen receptor, of PI3K/Akt and mitochondrial preservation. Therefore, genistein should not be only considered as an inhibitor of tyrosine kinase but also as a cardioprotective estrogen.

Topics: Animals; Calcium; Cardiotonic Agents; Estradiol; Genistein; In Vitro Techniques; Ischemic Preconditioning, Myocardial; Male; Mitochondria, Heart; Mitochondrial Swelling; Mitogen-Activated Protein Kinase Kinases; Myocardial Infarction; Myocardial Reperfusion Injury; Phosphatidylinositol 3-Kinases; Phytoestrogens; Proto-Oncogene Proteins c-akt; Rabbits; Receptors, Estrogen

Topics: Animals; Cholesterol, Dietary; Disease Models, Animal; Female; Genistein; Hypercholesterolemia; Male; Myocardial Infarction; Phytoestrogens; Rabbits; Risk Factors

We have previously shown that estrogen administered in ovariectomized female rabbits significantly reduce myocardial infarct size. We now investigated whether the phytoestrogen genistein similarly protects ischemic myocardium and whether this is associated with its antioxidant properties. In addition, we examined whether genistein abolishes preconditioning, since at high doses, it inhibits tyrosine kinase.. We studied five groups of New Zealand white female rabbits. Group A (n = 12) were normal controls, group B (n = 14) were ovariectomized 4 weeks prior to the experiment, group C (n = 10) were ovariectomized and treated with genistein (0.2 mg kg(-1) day(-1) subcutaneously) for 4 weeks before the experiment, group D (n = 12) had intact gonads and were treated with genistein (0.2 mg kg(-1) day(-1) subcutaneously) for 4 weeks before the experiment and group E (n = 8) were ovariectomized 4 weeks prior to the experiment and treated with a single dose of genistein (0.2 mg kg(-1) day(-1) subcutaneously) just prior to the experiment. All animals underwent 30 min of heart ischemia and 120 min of reperfusion, with (subgroup I) or without (subgroup II) preconditioning. Malondialdehyde (MDA) concentration just before the experiment was determined.. We found significant differences between the groups-p < 0.0001 in factorial ANOVA. The groups with preconditioning had significant smaller infarcts compared to those without-AI vs AII (10.66 +/- 1.42% vs 43.22 +/- 2.67%), BI vs BII (18.53 +/- 2.36% vs 43.05 +/- 8.37%), CI vs CII (10.17 +/- 2.07% vs 44.5 +/- 5.47%), DI vs DII (14.98 +/- 2.36% vs 37.79 +/- 3.92%) and EI vs EII (17.11 +/- 3.24% vs 42.08 +/- 3.42%), p < 0.0005. Ovariectomy was not associated with larger myocardial infarctions-AII vs BII, p = NS. Genistein, for 4 weeks, did not protect ischemic myocardium in either ovariectomized or non-ovariectomized animals-BII vs CII and AII vs DII, p = NS. There was no significant difference between the preconditioned animals, with intact gonads or ovariectomized (AI vs BI, p = NS), ovariectomized with or without genistein (BI vs CI, p = NS) and non-ovariectomized whether treated with genistein or not (AI vs DI, p = NS). A single dose of genistein did not offer any protection (EII vs BII, p = NS), nor did it modify the preconditioning effect (EI vs BI, p = NS). We found no significant difference in MDA plasma levels between the groups.. Genistein, at this dose, does not reduce infarct size per se nor abolishes the protection induced by preconditioning, in both ovariectomized and non-ovariectomized animals. Preconditioning offers myocardial protection in animals with intact gonads as well as estrogen deprived; bilateral ovariectomy, at least during short-term, is not associated with larger myocardial infarcts compared to control animals. In addition estrogen deprivation, during short term, as well as genistein do not modify oxidative stress.

Topics: Animals; Female; Genistein; Ischemic Preconditioning, Myocardial; Myocardial Infarction; Myocardium; Ovariectomy; Oxidative Stress; Phytoestrogens; Rabbits