Selected Phytoestrogens Distinguish Roles of ERα Transactivation and Ligand Binding for Anti-Inflammatory Activity.

Estrogen receptor α (ERα) is a ligand-activated transcriptional activator that is also involved vascular inflammation and atherosclerosis. Whether different ligands may affect this activity has not been explored. We screened a panel of phytoestrogens for their role in ERα binding and transcriptional transcription, and correlated the findings to anti-inflammatory activities in vascular endothelial cells stably expressing either a wild-type or mutant form of ERα deficient in its membrane association. Taxifolin and silymarin were "high binders" for ERα ligand binding; quercetin and curcumin were "high activators" for ERα transactivation. Using these phytoestrogens as functional probes, we found, in endothelial cells expressing wild-type ERα, the ERα high activator, but not the ERα high binder, promoted ERα nuclear translocation, estrogen response element (ERE) reporter activity, and the downstream gene expression. In endothelial cells expressing membrane association-deficient mutant ERα, the ERα nuclear translocation was significantly enhanced by taxifolin and silymarin, which still failed to activate ERα. Inflammation response was examined using the systemic or vascular inflammation inducers lipopolysaccharide or oxidized low-density lipoprotein. In both cases, only the ERα high activator inhibited nuclear translocation of nuclear factor κB, JNK, and p38, and the production of inflammatory cytokines IL-1ß and TNFα. We confirm a threshold nuclear accumulation of ERα is necessary for its transactivation. The anti-inflammatory activity of phytoestrogens is highly dependent on ERα transactivation, less so on the ligand binding, and independent of its membrane association. A pre-examination of phytoestrogens for their mode of ERα interaction could facilitate their development as better targeted receptor modifiers.

Bidirectional regulation of angiogenesis by phytoestrogens through estrogen receptor-mediated signaling networks.

Sex hormone estrogen is one of the most active intrinsic angiogenesis regulators; its therapeutic use has been limited due to its carcinogenic potential. Plant-derived phytoestrogens are attractive alternatives, but reports on their angiogenic activities often lack in-depth analysis and sometimes are controversial. Herein, we report a data-mining study with the existing literature, using IPA system to classify and characterize phytoestrogens based on their angiogenic properties and pharmacological consequences. We found that pro-angiogenic phytoestrogens functioned predominantly as cardiovascular protectors whereas anti-angiogenic phytoestrogens played a role in cancer prevention and therapy. This bidirectional regulation were shown to be target-selective and, for the most part, estrogen-receptor-dependent. The transactivation properties of ERα and ERß by phytoestrogens were examined in the context of angiogenesis-related gene transcription. ERα and ERß were shown to signal in opposite ways when complexed with the phytoestrogen for bidirectional regulation of angiogenesis. With ERα, phytoestrogen activated or inhibited transcription of some angiogenesis-related genes, resulting in the promotion of angiogenesis, whereas, with ERß, phytoestrogen regulated transcription of angiogenesis-related genes, resulting in inhibition of angiogenesis. Therefore, the selectivity of phytoestrogen to ERα and ERß may be critical in the balance of pro- or anti-angiogenesis process.

Vascular reactivity screen of Chinese medicine danhong injection identifies Danshensu as a NO-independent but PGI2-mediated relaxation factor.

Danhong injection (DHI) is the most prescribed injection form of Chinese medicine for the treatment of cardiovascular diseases such as atherosclerosis, angina pectoris, and stroke in China. However, its active components and action mechanisms remain poorly defined. We hypothesized that DHI contains active components that could prevent and restore endothelial dysfunction by improving vascular relaxation activity. DHI increased vasorelaxation in vivo and ex vivo of rat aortas. Vascular reactivity screen identified that danshensu was the major relaxation factor in DHI. DHI-mediated endothelial-dependent vasorelaxation was independent on nitric oxide/endothelial nitric oxide synthase but was via prostacyclin pathway by increasing cyclooxygenase (COX)-2 gene expression and prostacyclin production. Our results revealed a previously unknown endothelium-dependent vasorelaxation mechanism by danshensu and together with previously reported activity on ion channels of vascular smooth muscle cells, demonstrated that its dual actions contribute to a multicomponent Chinese herbal medicine that synergistically targets different pathways to achieve its well-documented cardiovascular protective effects.

Long-term safety and efficacy of a combination of niacin extended release and simvastatin in patients with dyslipidemia: the OCEANS study.

INTRODUCTION: High-dose HMG-CoA reductase inhibitors (statins) fail to prevent approximately two-thirds of cardiovascular events. This fact has focused increased attention on treating abnormalities of non-high-density lipoprotein-cholesterol (non-HDL-C), HDL-C, and triglycerides in national guidelines and has intensified interest in combination therapy. METHODS: The OCEANS study (Open-label evaluation of the safety and efficacy of a Combination of niacin ER and simvAstatin in patieNts with dySlipidemia; ClinicalTrials.gov identifier: NCT00080275) evaluated the safety and efficacy of a combination of niacin extended release and simvastatin (NER/S; SIMCOR) over 52 weeks in 520 patients with mixed dyslipidemia. After a >or=4-week run-in phase of diet modification and simvastatin 40 mg/day, median baseline values (mg/dL) were: non-HDL-C = 141, low-density lipoprotein-cholesterol (LDL-C) = 110, HDL-C = 45, and triglyceride = 151. Patients were randomized to an 8- or 12-week niacin titration scheme to a maximum NER/S dosage of 2,000/40 mg/day. RESULTS: Differences between titration groups in tolerability, safety, and efficacy were minimal; therefore, all results are for pooled titration groups. The safety of NER/S was consistent with the safety profile of each individual component. Treatment with NER/S was well tolerated: 71% of patients experienced flushing and 92% of flushing episodes were mild or moderate in intensity. Overall, 61% of patients experienced flushing episodes that were rated as mild or moderate in intensity. Flushing decreased over time: <40% of those who had flushing during titration experienced flushing during the final 12 weeks. A total of 20% of patients discontinued treatment because of a treatment-related adverse event, including 7% who discontinued because of flushing. Median changes from baseline (following the simvastatin 40 mg/day run-in phase) to 24 weeks were: non-HDL-C = -27.3%, LDL-C = -25.0%, HDL-C = +23.9%, and triglycerides = -35.9% (all p < 0.0001 vs baseline). In lipid-treatment-naive patients, NER/S 2,000/40 mg/day decreased non-HDL-C, LDL-C, and triglycerides by approximately 50% and increased HDL-C by approximately 25% when week-24 lipid values were compared with lipid values obtained prior to the simvastatin 40 mg/day run-in. All three therapeutic lipid targets (LDL-C [risk-adjusted goal], HDL-C >or=40 mg/dL, and triglycerides <150 mg/dL) were achieved concurrently by 65% of patients treated with NER/S. CONCLUSION: Treatment with NER/S 2,000/40 mg/day is well tolerated, has no unanticipated adverse events, and provides additional, clinically relevant improvements in multiple lipid parameters beyond statin monotherapy.

Comparison of the efficacy and safety of a combination tablet of niacin extended-release and simvastatin with simvastatin 80 mg monotherapy: the SEACOAST II (high-dose) study.

BACKGROUND: The number of patients with multiple lipid abnormalities is increasing. Lipid treatment guidelines are established for low-density lipoprotein cholesterol (LDL-C) and non-high-density lipoprotein cholesterol (non-HDL-C). The importance of treating HDL-C and triglycerides is gaining recognition. OBJECTIVE: To determine, in patients who had been treated previously with simvastatin 40 mg/day, the efficacy, safety, and tolerability of two regimens of a combination of proprietary niacin, extended-release core, coated with 40 mg/day simvastatin (NER/S), compared to 80 mg/day simvastatin monotherapy (S80). METHODS: High-risk patients (n = 343) with dyslipidemia were treated for 24 weeks with NER/S (1000/40 mg/day or 2000/40 mg/day) or S80. RESULTS: Median percentage change from baseline to week 24 in non-HDL-C in either NER/S group was noninferior to S80 (-11.3%, -17.1%, and -10.1%, respectively). Changes in LDL-C were comparable (-8.6%, -11.6%, and -12.7%, respectively). Doubling the dose of simvastatin (S80) did not alter HDL-C, triglycerides, or lipoprotein(a); however, both NER/S doses resulted in significant improvements in all three parameters (+21.9%, -31.8%, and -21.0%, respectively, for NER/S 2000/40 mg/day). The safety of NER/S was consistent with the safety profile of each individual component. Treatment with both doses of NER/S was well tolerated; 59% of patients experienced flushing, 78% of flushing was mild or moderate in intensity, 49% of those who flushed during dose titration did not flush during weeks 13 to 24, and only 4.6% of patients discontinued because of flushing. CONCLUSION: NER/S provides similar reductions in non-HDL-C and LDL-C compared to doubling the simvastatin dose to 80 mg; however, only NER/S resulted in improvements in HDL-C, triglycerides, and lipoprotein(a).

Effect of soy protein from differently processed products on cardiovascular disease risk factors and vascular endothelial function in hypercholesterolemic subjects.

BACKGROUND: The magnitude of the effect of soy protein on lipoprotein concentrations is variable. This discordance is likely attributable to the various forms of soy protein used and to unrecognized shifts in dietary fatty acid, cholesterol, and fiber. OBJECTIVE: The objective was to evaluate the effect of soybean processing as well as soy consumption relative to animal protein, independent of alterations in major dietary variables, on cardiovascular disease risk factors and vascular endothelial function. DESIGN: Twenty-eight hypercholesterolemic subjects (LDL cholesterol >/=3.36 mmol/L) aged >50 y consumed each of 4 diets for 6-wk periods according to a randomized crossover design. The diets [55% of energy as carbohydrate, 30% of energy as fat, and 15% of energy as protein-7.5% of energy as experimental protein (37.5 g/d)] were designed to contain products made from either whole soybeans, soyflour, or soymilk and were compared with a diet containing an equivalent amount of animal protein (meat, chicken, and dairy products). The cholesterol, fiber, and fatty acid profiles of the diets were equalized. All food and drink were provided, and body weight was maintained throughout the study. RESULTS: No significant differences in blood pressure, vascular endothelial function, or total cholesterol, VLDL-cholesterol, triacylglycerol, apolipoprotein B, or C-reactive protein concentrations were observed between the diets. Consumption of the soymilk diet resulted in a modest decrease (4%) in LDL-cholesterol concentrations compared with the animal-protein and soyflour diets (P < 0.05) and higher HDL-cholesterol (1%) and apolipoprotein A-I (2%) concentrations compared with the soybean and soyflour diets (P < 0.05). CONCLUSIONS: The results suggest that the consumption of differently processed soy-based products and different types of protein (animal and soy) has little clinical effect on cardiovascular disease risk factors, including peripheral endothelial function, when other major dietary variables are held constant.

p38 mitogen-activated protein kinase activates eNOS in endothelial cells by an estrogen receptor alpha-dependent pathway in response to black tea polyphenols.

Black tea has been shown to improve endothelial function in patients with coronary artery disease and recent data indicate the polyphenol fraction of black tea enhances endothelial nitric oxide synthase (eNOS) activity through p38 MAP kinase (p38 MAPK) activation. Because the mechanisms for this phenomenon are not yet clear, we sought to elucidate the signaling events in response to black tea polyphenols. Bovine aortic endothelial cells (BAECs) exposed to black tea polyphenols demonstrated eNOS activation that was inhibited by the estrogen receptor (ER) antagonist ICI 182,780, and siRNA-mediated silencing of ER expression. Consistent with this observation, black tea polyphenols induced time-dependent phosphorylation of ERalpha on Ser-118 that was inhibited by ICI 182,780. Phosphorylation of ERalpha on Ser-118 was due to p38 MAP kinase (p38 MAPK) as, it was inhibited by SB203580 and overexpression of dominant-negative p38alpha MAPK. Conversely, constitutively active MKK6 induced p38 MAPK activation that recapitulated the effects of polyphenols by inducing ERalpha phosphorylation and downstream activation of Akt, and eNOS. The key role of ERalpha Ser-118 phosphorylation was confirmed in eNOS-transfected COS-7 cells, as polyphenol-induced eNOS activation required cotransfection with ERalpha subject to phosphorylation at Ser-118. This residue appeared critical for functional association of ERalpha with p38 MAPK as ERalpha with Ser-118 mutated to alanine could not form a complex with p38 MAPK. These findings suggest p38 MAP kinase-mediated eNOS activation requires ERalpha and these data uncover a new mechanism of ERalpha activation that has broad implications for NO bioactivity and endothelial cell phenotype.