The soyabean isoflavone genistein modulates endothelial cell behaviour

(R,S)-Equol 7-β-D-glucuronide, but not other circulating isoflavone metabolites, modulates migration and tubulogenesis in human aortic endothelial cells targeting the VEGF pathway

Current knowledge indicates that the consumption of isoflavone-rich foodstuffs can have a beneficial impact on cardiovascular health. To what extent these isoflavones act as the main actors of that benefit is less clear. Genistein (GEN), daidzein (DAZ), and the DAZ-derived microbial metabolite equol (Eq) exhibit antiangiogenic effects in vitro, but their low bloodstream concentrations make it difficult to rationalize the in vivo effects. Their derived phase-II metabolites (glucuronides and sulfates) are major metabolites found in plasma, but their role as antiangiogenic molecules remains unexplored. We aimed here to first assess the anti-angiogenic activities of the main circulating isoflavone metabolites (glucuronides and sulfates) and compare them with their corresponding free forms at physiological concentrations (0.1-10 μM). The effects of the conjugated vs. free forms on tubulogenesis, cell migration, and VEGF-induced signalling were investigated in primary human aortic endothelial cells (HAECs). While (R,S)-equol 7-β-D-glucuronide (Eq 7-glur) exerted dose-dependent inhibition of tubulogenesis and endothelial migration comparable to that exerted by the free forms (GEN, DAZ, and Eq), the rest of the phase-II conjugates exhibited no significant effects. The underlying molecular mechanisms were independent of the bFGF but related to the modulation of the VEGF pathway. Besides, the observed dissimilar cellular metabolism (conjugation/deconjugation) places the phase-II metabolites as precursors of the free forms; however, the question of whether this metabolism impacts their biological activity requires additional studies. These new insights suggest that isoflavones and their circulating metabolites, including Eq 7-glur, may be involved in cardiovascular health (e.g., targeting angiogenesis).

A soybean-based diet modulates cadmium-induced vascular apoptosis

Cadmium (Cd) exposure has been associated with an increased risk of cardiovascular diseases. The diet is a modifiable source of protecting or damaging factors that may affect this risk. Herein we tested the hypothesis that a soybean-based diet (SBD) protects the vascular wall of the aorta against Cd-induced pro-inflammatory and pro-apoptotic effects. To test this hypothesis, we fed male Wistar rats for 60 days with a casein-based diet (CBD) or an SBD. These animals were also exposed to tap-water without (CBD-Co/SBD-Co) or with 15(CBD-15Cd/SBD-15Cd) or 100 (CBD-100Cd/SBD-100Cd) ppm of Cd. Inflammatory parameters (mRNAs and/or proteins) were measured in thoracic aorta tissue. These included inducible and endothelial nitric oxide synthases, cyclooxygenase-2, intracellular-adhesion molecule-1, and vascular cell-adhesion molecule-1. As pro-apoptotic parameters, we measured Bax and Bcl-2 mRNA/protein, as well as TUNEL positive cells in the aorta tissue. Compared to CBD-Co, inflammatory and apoptosis markers increased in the aorta with the concentration of Cd in the drinking water. These effects were not observed in either SBD-15Cd or SBD-100Cd, which were similar to CBD-Co. Cd content in serum and in aortas from animals fed CBD-Co/SBD-15Cd or CBD-Co/SBD-100Cd were similar suggesting that, if any, the effect of SBD is not due to changes in Cd bioaccumulation, but due to secondary effects linked to the composition of the dietary soybean flour. Our findings are consistent with a protective effect of an SBD against Cd-induced inflammation and apoptosis in the thoracic aorta in a rat model.

Comparison of liver gene expression by RNAseq and PCR analysis after 8 weeks of feeding soy protein isolate- or casein-based diets in an obese liver steatosis rat model

Differential expression of genes provides insight into fundamental mechanisms associated with the ability of soy protein isolate to attenuate liver steatosis in genetically obese rats.

Phytoestrogen-Rich Natural Preparation for Treatment of Climacteric Syndrome and Atherosclerosis Prevention in Perimenopausal Women

The present study evaluated the risks and benefits of phytoestrogen treatment in healthy perimenopausal women in relation to the dynamics of climacteric syndrome and progression of atherosclerosis. Study participants were treated with placebo or phytoestrogen-rich natural preparation Karinat based on grape (Vitis vinifera) seeds, green tea (Camellia sinensis) leaves, hop (Hunulus lupulus) cone powder and garlic (Allium sativum) powder. The dynamics of climacteric syndrome was evaluated by Kupperman Index and Utian Quality of Life Scale. Atherosclerosis progression was evaluated by measuring carotid intima-media thickness. Significant changes of climacteric syndrome's severity in both Karinat and placebo groups (p = 0.005 and p = 0.001) were obtained after 24 months of follow-up. Detailed analysis of Kupperman Index suggested that Karinat possessed a significant effect on nervousness (p = 0.010), weakness (p = 0.020) and formication (p = 0.010). A significant improvement of medical (p = 0.070) and emotional (p = 0.060) components of Kupperman Index and Utian Quality of Life Scale was also observed in Karinat group. However, difference in carotid intima-media thickness between the two groups was not statistically significant at follow-up. A slight positive effect of phytoestrogens on climacteric syndrome manifestations was demonstrated in this study. Karinat can be used for alleviation of climacteric syndrome and cardiovascular disease prevention in perimenopausal women. Copyright © 2017 John Wiley & Sons, Ltd.

Vascular action of bisphosphonates: In vitro effect of alendronate on the regulation of cellular events involved in vessel pathogenesis

In this work we investigate whether, despite the procalcific action of alendronate on bone, the drug would be able to regulate in vitro the main cellular events that take part in atherosclerotic lesion generation. Using endothelial cell cultures we showed that Alendronate (1-50μM) acutely enhances nitric oxide production (10-30min). This stimulatory action of the bisphosphonate involves the participation of MAPK signaling transduction pathway. Under inflammatory stress, the drug reduces monocytes and platelets interactions with endothelial cells induced by lipopolysaccharide. Indeed the bisphophonate exhibits a significant inhibition of endothelial dependent platelet aggregation. The molecular mechanism of alendronate (ALN) on leukocyte adhesion depends on the regulation of the expression of cell adhesion related genes (VCAM-1; ICAM-1); meanwhile the antiplatelet activity is associated with the effect of the drug on nitric oxide production. On vascular smooth muscle cells, the drug exhibits ability to decrease osteogenic transdifferentiation and extracellular matrix mineralization. When vascular smooth muscle cells were cultured in osteogenic medium for 21days, they exhibited an upregulation of calcification markers (RUNX2 and TNAP), high alkaline phosphatase activity and a great amount of mineralization nodules. ALN treatment significantly down-regulates mRNA levels of osteoblasts markers; diminishes alkaline phosphatase activity and reduces the extracellular calcium deposition. The effect of ALN on vascular cells differs from its own bone action. On calvarial osteoblasts ALN induces cell proliferation, enhances alkaline phosphatase activity, and increases mineralization, but does not affect nitric oxide synthesis. Our results support the hypothesis that ALN is an active drug at vascular level that regulates key processes involved in vascular pathogenesis through a direct action on vessel cells.

Anti-Atherosclerotic Effects of a Phytoestrogen-Rich Herbal Preparation in Postmenopausal Women

The risk of cardiovascular disease and atherosclerosis progression is significantly increased after menopause, probably due to the decrease of estrogen levels. The use of hormone replacement therapy (HRT) for prevention of cardiovascular disease in older postmenopausal failed to meet expectations. Phytoestrogens may induce some improvements in climacteric symptoms, but their effect on the progression of atherosclerosis remains unclear. The reduction of cholesterol accumulation at the cellular level should lead to inhibition of the atherosclerotic process in the arterial wall. The inhibition of intracellular lipid deposition with isoflavonoids was suggested as the effective way for the prevention of plaque formation in the arterial wall. The aim of this double-blind, placebo-controlled clinical study was to investigate the effect of an isoflavonoid-rich herbal preparation on atherosclerosis progression in postmenopausal women free of overt cardiovascular disease. One hundred fifty-seven healthy postmenopausal women (age 65 ± 6) were randomized to a 500 mg isoflavonoid-rich herbal preparation containing tannins from grape seeds, green tea leaves, hop cone powder, and garlic powder, or placebo. Conventional cardiovascular risk factors and intima-media thickness of common carotid arteries (cIMT) were evaluated at the baseline and after 12 months of treatment. After 12-months follow-up, total cholesterol decreased by 6.3% in isoflavonoid-rich herbal preparation recipients (p = 0.011) and by 5.2% in placebo recipients (p = 0.020); low density lipoprotein (LDL) cholesterol decreased by 7.6% in isoflavonoid-rich herbal preparation recipients (p = 0.040) and by 5.2% in placebo recipients (non-significant, NS); high density lipoprotein (HDL) cholesterol decreased by 3.4% in isoflavonoid-rich herbal preparation recipients (NS) and by 4.5% in placebo recipients (p = 0.038); triglycerides decreased by 6.0% in isoflavonoid-rich herbal preparation recipients (NS) and by 7.1% in placebo recipients (NS). The differences between lipid changes in the isoflavonoid-rich herbal preparation and placebo recipients did not reach statistical significance (p > 0.05). Nevertheless, the mean cIMT progression was significantly lower in isoflavonoid-rich herbal preparation recipients as compared to the placebo group (6 μm, or <1%, versus 100 μm, or 13%; p < 0.001 for the difference). The growth of existing atherosclerotic plaques in isoflavonoid-rich herbal preparation recipients was inhibited by 1.5-fold (27% versus 41% in the placebo group). The obtained results demonstrate that the use of isoflavonoid-rich herbal preparation in postmenopausal women may suppress the formation of new atherosclerotic lesions and reduce the progression of existing ones, thus promising new drug for anti-atherosclerotic therapy. Nevertheless, further studies are required to confirm these findings.

Genistein ameliorated endothelial nitric oxidase synthase uncoupling by stimulating sirtuin-1 pathway in ox-LDL-injured HUVECs

Endothelial nitric oxidase synthase (eNOS) uncoupling plays a causal role in endothelial dysfunction in atherosclerosis. Genistein consumption has been associated with the prevention of atherosclerosis. However, the effect of genistein on eNOS uncoupling has not been reported. A model of oxidized low-density lipoprotein (ox-LDL)-induced injury on human umbilical vein endothelial cells (HUVECs) was established to evaluate the effect of genistein on eNOS uncoupling. We investigated the effect of genistein on NADPH oxidase-dependent superoxide production, NOX4 expression, BH4 synthesis and oxidation, the expression of GTP cyclohydrolase 1 (GCH1) and dihydrofolate reductase (DHFR). The results showed that genistein decreased superoxide production and NOX4 expression, enhanced the ratio of BH4/BH2, augmented the expressions of GCH1 and DHFR. Accompanied with genistein ameliorating eNOS uncoupling, genistein elevated the expression of sirtuin-1; furthermore, the effects of genistein on eNOS uncoupling were blunted with sirtuin-1 siRNA. The present study indicated that genistein ameliorated eNOS uncoupling was concerned with sirtuin-1 pathway in ox-LDL-injured HUVECs.

The role of sex steroids on cellular events involved in vascular disease

In this work we checked the hypothesis whether estrone, progesterone, and testosterone are able to modulate the interactions between platelets, monocytes, and endothelial cells either under basal or inflammatory conditions. Using adhesion assays we demonstrated that pretreatment of endothelial cells with estrone, progesterone, or testosterone prevented monocytes and platelets adhesion induced by the proinflammatory agent bacterial lipopolysaccharide. The hormones reduced the expression of mRNA of ICAM-1, VCAM-1, and P-selectin, endothelial surface proteins that mediate monocytes and platelets adhesion respectively. Integrins are the main leukocyte proteins that allow firm adhesion. Using flow cytometry we showed that estrone treatment of monocytes reduced CD11b and CD11c expression, either under basal or injury (lipopolysaccharide) conditions. The three steroids inhibited platelet aggregation in a nitric oxide dependent manner. Platelet function was not affected by the steroid treatment. The molecular mechanisms of action exerted by the steroids included the participation of the intracellular signaling pathways PKC, MAPK, and PI3K, which selectively and differentially mediate the stimulation of nitric oxide release. We evidence that estrone, progesterone, and testosterone modulate monocyte and platelet adhesion to endothelial cells, events that play a major role in the initiation and progression of vascular lesions. The steroid action was evidenced under basal or inflammatory conditions. The mechanisms of action exerted by the steroids included stimulation of nitric oxide production and the participation of PKC, MAPK, and PI3K systems.

Genistein inhibits cell invasion and motility by inducing cell differentiation in murine osteosarcoma cell line LM8

Background

One of the problems associated with osteosarcoma is the frequent formation of micrometastases in the lung prior to diagnosis because the development of metastatic lesions often causes a fatal outcome. Therefore, the prevention of pulmonary metastases during the early stage of tumor development is critical for the improvement of the prognosis of osteosarcoma patients. In Japan, soy is consumed in a wide variety of forms, such as miso soup and soy sauce. The purpose of this study is to investigate the effect of genistein, an isoflavone found in soy, on the invasive and motile potential of osteosarcoma cells.

Methods

LM8 cells were treated for 3 days with various concentrations of genistein. The effect of genistein on cell proliferation was determined by DNA measurement in the cultures and 5-bromo-2’-deoxyuridine (BrdU) incorporation study. The assays of cell invasion and motility were performed using the cell culture inserts with either matrigel-coated membranes or uncoated membranes in the invasion chambers. The expression and secretion of MMP-2 were determined by immunohistochemistry and gelatin zymography. The subcellular localization and cellular level of β-catenin were determined by immunofluorescence and Western blot. For examining cell morphology, the ethanol-fixed cells were stained with hematoxylin-eosin (H&E). The expression of osteocalcin mRNA was determined by reverse transcription-polymerase chain reaction (RT-PCR).

Results

Genistein dose-dependently inhibits cell proliferation. Genistein-treated cells were less invasive and less motile than untreated cells. The expression and secretion of MMP-2 were lower in the genistein-treated cultures than in the untreated cultures. β-Catenin in untreated cells was located in the cytoplasm and/or nucleus, while in genistein-treated cells it was translocated near to the plasma membrane. The level of β-catenin was higher in genistein-treated cells than in untreated cells. Treatment of LM8 cells with genistein induced morphological changes, markedly decreased the formation of multilayer masses of cells, and markedly increased the expression of osteocalcin mRNA.

Conclusions

Genistein decreased invasive and motile potential by inducing cell differentiation in LM8 cells. Genistein may be useful as an anti-metastatic drug for osteosarcoma through its differentiation-inducing effects.

Vascular effects of phytoestrogens and alternative menopausal hormone therapy in cardiovascular disease

Phytoestrogens are estrogenic compounds of plant origin classified into different groups including isoflavones, lignans, coumestans and stilbenes. Isoflavones such as genistein and daidzein are the most studied and most potent phytoestrogens, and are found mainly in soy based foods. The effects of phytoestrogens are partly mediated via estrogen receptors (ERs): ERα, ERβ and possibly GPER. The interaction of phytoestrogens with ERs is thought to induce both genomic and non-genomic effects in many tissues including the vasculature. Some phytoestrogens such as genistein have additional non-ER-mediated effects involving signaling pathways such as tyrosine kinase. Experimental studies have shown beneficial effects of phytoestrogens on endothelial cells, vascular smooth muscle, and extracellular matrix. Phytoestrogens may also affect other pathophysiologic vascular processes such as lipid profile, angiogenesis, inflammation, tissue damage by reactive oxygen species, and these effects could delay the progression of atherosclerosis. As recent clinical trials showed no vascular benefits or even increased risk of cardiovascular disease (CVD) and CV events with conventional menopausal hormone therapy (MHT), phytoestrogens are being considered as alternatives to pharmacologic MHT. Epidemiological studies in the Far East population suggest that dietary intake of phytoestrogens may contribute to the decreased incidence of postmenopausal CVD and thromboembolic events. Also, the WHO-CARDIAC study supported that consumption of high soybean diet is associated with lower mortalities from coronary artery disease. However, as with estrogen, there has been some discrepancy between the experimental studies demonstrating the vascular benefits of phytoestrogens and the data from clinical trials. This is likely because the phytoestrogens clinical trials have been limited in many aspects including the number of participants enrolled, the clinical end points investigated, and the lack of long-term follow-up. Further investigation of the cellular mechanisms underlying the vascular effects of phytoestrogens and careful evaluation of the epidemiological evidence and clinical trials of their potential vascular benefits would put forward the use of phytoestrogens as an alternative MHT for the relief of menopausal symptoms and amelioration of postmenopausal CVD.

Cellular actions of testosterone in vascular cells: mechanism independent of aromatization to estradiol

In this work we investigated the role of testosterone on cellular processes involved in vascular disease, and whether these effects depend on its local conversion to estradiol. Cultures of rat aortic endothelial and smooth muscle cells in vitro treated with physiological concentrations of testosterone were employed. Testosterone rapidly increased endothelial nitric oxide production. To evaluate whether this non genomic action was dependent on testosterone aromatization we used an aromatase inhibitor. Anastrozole compound did not modify the fast increase in nitric oxide production elicited by testosterone. The hormonal effect was completely blocked by an androgen receptor antagonist (flutamide); meanwhile it wasn't modified by the presence of an estrogen receptor antagonist (ICI182780).The possibility of intracellular estradiol synthesis was ruled out when no differences were found in estradiol measurements performed in culture incubation medium from control and testosterone treated cells. The 5α-reductase inhibitor finasteride partially suppressed the enhancement in nitric oxide production, suggesting that the effect of testosterone was partially due to dihydrotestosterone conversion. Testosterone stimulated muscle cell proliferation independent of local conversion to estradiol. When cellular events that play key roles in vascular disease development were analyzed, testosterone prevented monocyte adhesion to endothelial cells induced by a proinflammatory stimulus (bacterial lipopolysaccharides), and prompted muscle cell migration in presence of a cell motility inducer. In summary, testosterone modulates vascular behavior through its direct action on vascular cells independent of aromatization to estradiol. The cellular actions exhibited by the steroid varied whether cells were under basal or inflammatory conditions.

Activation of nuclear factor erythroid 2-related factor 2 and PPARγ plays a role in the genistein-mediated attenuation of oxidative stress-induced endothelial cell injury

We investigate the cytoprotective effects and the molecular mechanism of genistein in oxidative stress-induced injury using an endothelial cell line (EA.hy926). An oxidative stress model was established by incubating endothelial cells with H₂O₂. According to the present results, genistein pretreatment protected endothelial cells against H₂O₂-induced decreases in cell viability and increases in apoptosis. Genistein also prevented the inhibition of B-cell lymphoma 2 and the activation of caspase-3 induced by H₂O₂. Genistein increased superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) levels and attenuated the decrease in these antioxidants during oxidative stress. We also found that genistein induced the promoter activity of both nuclear factor erythroid 2-related factor 2 (Nrf2) and PPARγ. Additionally, genistein induced the nuclear translocation of Nrf2 and PPARγ. While genistein caused the up-regulation of both Nrf2 and PPARγ, it also activated and up-regulated the protein expression and transcription of a downstream protein, haem oxygenase-1 (HO-1). Moreover, the use of Nrf2 small interfering RNA transfection and HO-1- or PPARγ-specific antagonists (Znpp and GW9662, respectively) blocked the protective effects of genistein on endothelial cell viability during oxidative stress. Therefore, we conclude that oxidative stress-induced endothelial cell injury can be attenuated by treatment with genistein, which functions via the regulation of the Nrf2 and PPARγ signalling pathway. Additionally, the endogenous antioxidants SOD, CAT and GSH appear to play a role in the antioxidant activity of genistein. The present findings suggest that the beneficial effects of genistein involving the activation of cytoprotective antioxidant genes may represent a novel strategy in the prevention and treatment of cardiovascular endothelial damage.

Testosterone modulates platelet aggregation and endothelial cell growth through nitric oxide pathway

The aim of the present study was to investigate the effect of testosterone on the modulation of cellular events associated with vascular homeostasis. In rat aortic strips, 5-20 min treatment with physiological concentrations of testosterone significantly increased nitric oxide (NO) production. The rapid action of the steroid was suppressed by the presence of an androgen receptor antagonist (flutamide). We obtained evidence that the enhancement in NO synthesis was dependent on the influx of calcium from extracellular medium, because in the presence of a calcium channel blocker (verapamil) the effect of testosterone was reduced. Using endothelial cell (EC) cultures, we demonstrated that androgen directly acts at the endothelial level. Chelerythrine or PD98059 compound completely suppressed the increase in NO production, suggesting that the mechanism of action of the steroid involves protein kinase C and mitogen-activated protein kinase pathways. It is known that endothelial NO released into the vascular lumen serves as an inhibitor of platelet activation and aggregation. We showed that testosterone inhibited platelet aggregation and this effect was dependent on endothelial NO synthesis. Indeed, the enhancement of NO production elicited by androgen was associated with EC growth. The steroid significantly increased DNA synthesis after 24 h of treatment, and this mitogenic action was blunted in the presence of NO synthase inhibitor N-nitro-l-arginine methyl ester. In summary, testosterone modulates vascular EC growth and platelet aggregation through its direct action on endothelial NO production.

Protective effects of 7-difluoromethyl-5,4'-dimethoxygenistein against human aorta endothelial injury caused by lysophosphatidyl choline

7-Difluoromethyl-5,4'-dimethoxygenistein (DFMG) is an active new derivative of genistein (GEN). It has shown effective protection in vascular endothelial injury. To further investigate its potential protective effects and its mechanism probably related to atherosclerosis, in present study, human aorta endothelial cells (HAECs) were chosen and treated with various concentrations of lysophosphatidyl choline (LPC) to establish an experimental model. Results showed that 10.0 μmol/l of LPC was optimal for inducing HAEC injury. DFMG pretreatment was able to prevent HAEC injury induced by LPC and restore cell viability in a concentration-dependent manner. The protective efficacy of DFMG (10.0 μmol/l) was significantly greater than that of GEN (10.0 μmol/l) and vitamin E (50.0 μmol/l). The mechanisms underlying the protective effects of DFMG are related to the activation of the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase and to the clearance of intracellular reactive oxygen species. DFMG inhibits the apoptosis of HAECs mediated by LPC involving the blockage of the mitochondrial apoptotic pathway.

Cellular and molecular actions displayed by estrone on vascular endothelium

In this work we provide evidence that estrone "per se" modulates cellular endothelial growth and survival, events that play key roles in the development of vascular disease. Moreover, under oxidative stress conditions the hormone prevented apoptosis triggered by hydrogen peroxide. Although estrone did not affect E-selectin and VCAM-1 mRNAs synthesis, the hormone prevented the expression of these adhesion molecules induced by the proinflammatory agent LPS. The steroid partially attenuated leukocyte adhesion not only under basal conditions but also in the presence of LPS. Using ICI182780 compound as estrogen receptor antagonist, and PD98059 as MAPK inhibitor we obtained evidence that the mitogenic action of estrone involved the participation of ER and MAPK transduction pathway activation. The presence of estradiol impaired the effect of estrone on cell proliferation and vasoactive production. These results suggest that estrone exhibits a remarkable biological action on endothelial cells, modulating vasoactive production, proliferation, apoptosis, and cell adhesion events.