Soy protein with isoflavones has favorable effects on endothelial function that are independent of lipid and antioxidant effects in healthy postmenopausal women

BACKGROUND: Controversy exists about the ability of soy protein and isoflavones to modulate vascular reactivity and biochemical cardiovascular disease risk markers in healthy, normolipidemic postmenopausal women. OBJECTIVE: The objective was to investigate whether the consumption of soy protein with isoflavones would result in improved vascular reactivity and decreased biochemical markers of endothelial dysfunction and inflammation, independent of enhanced lipid and antioxidant effects. DESIGN: Healthy postmenopausal women (n = 28) were enrolled in a randomized, double-blind, crossover study, and they consumed 25 g of 3 protein products/d for 6 wk each, with intervening washout periods. The products were isolated soy protein with isoflavones, ethanol-washed isolated soy protein with trace isoflavones, and total milk protein, which supplied 107, 2, and 0 mg total isoflavone (aglycone) units/d, respectively. We studied vascular function by using brachial artery reactivity values, plasma concentrations of vasoactive factors, endothelial inflammatory markers, and plasma isoflavone concentrations. The resistance of whole plasma and isolated LDL to copper-mediated oxidation was measured by conjugated diene formation. RESULTS: Postocclusion peak flow velocity of the brachial artery was significantly (P = 0.03) lower after treatment with isolated soy protein with isoflavones, which is consistent with a vasodilatory response, than after treatment with total milk protein. Plasma isoflavones and metabolites were significantly (P < 0.01) higher after treatment with isolated soy protein with isoflavones. There were no significant changes in biochemical cardiovascular disease risk markers or conjugated diene formation between the 3 dietary groups. CONCLUSION: Daily consumption of soy protein with isoflavones can result in positive vascular effects that are independent of lipid and antioxidant effects in healthy postmenopausal women.     

Anti-inflammatory effects of daidzein on primary astroglial cell culture

Abstract

Introduction: Alzheimer's disease is the common cause of dementia in old people. The pathological hallmarks of Alzheimer's disease include neuronal loss, deposition of amyloid-β, and presence of neurofibrillary tangles. The endogenous steroid estrogen has been shown to affect neuronal growth, differentiation and survival, while isoflavones also have a neuroprotective effect on human cortical neurons. Daidzein, however, has a superior neuron-protective effect to other isoflavones. The present study is to determine whether daidzein is able to inhibit the production of pro-inflammatory mediators under amyloid-β and lipopolysaccharide stimulation.

Materials and methods: Astrocyte cells were stimulated with amyloid-β or lipopolysaccharide in the absence and presence of diadzein. Nitric oxide released into the culture media was determined using the Griess reaction, and concentrations of IL-1, IL-6, TNF-α and estrogen receptor gene expression were measured by semi-quantitative real-time polymerase chain reaction assay.

Results: Diadzein-treatment increases astrocyte cell counts and attains its maximal effect at the 10^?12M concentration. The addition of 20 μM amyloid-β or 10^?6 g/ml LPS can significantly decrease the viability of astrocytes, up-regulated IL-1, IL-6, TNF-α mRNA and estrogen receptor expression; in addition, 1-h daidzein pre-treatment can restore the decreased viability of astrocytes induced by amyloid-β or lipopolysaccharide as well as down-regulate their mRNA expression.

Conclusions: It seems that this response is estrogen receptor-mediated. These results further increase the possibility that daidzein may have potential to ameliorate the inflammatory process and also alleviate the risk of Alzheimer's disease progression.     

A comparative study of growth-inhibitory effects of isoflavones and their metabolites on human breast and prostate cancer cell lines

The possible growth-inhibitory properties of the recently synthesized novel metabolite 1-(2,4-dihydrobenzoyl)-1-(4-hydroxyphenyl)ethylene (2-de-O-DMA) and six other metabolites of isoflavones were investigated and compared with those of the major isoflavones genistein, daidzein, and glycitein on human breast noncancer and breast and prostate cancer cell lines in vitro. The novel metabolite 2-de-O-DMA was found to be a more potent inhibitor than genistein on human breast cancer MCF-7, MDA-MB-468, and SK-BR-3 cells and breast noncancer MCF-10A cells. In prostate cancer cell lines, LNCaP and DU145, 2-de-O-DMA elicited a six- to sevenfold more potent inhibition than genistein. Flow cytometric analysis showed that 2-de-O-DMA and genistein blocked cells at the G2/M phase of the cell cycle. Genistein and 2-de-O-DMA led to apoptosis of a variety of cancer cell lines. The rapid response of growth inhibition induced by 2-de-O-DMA compared with genistein strongly suggests that the observed antiproliferation effects elicited by this novel metabolite are mediated via a biological pathway different from that induced by genistein. 2-de-O-DMA, a novel metabolite of isoflavone, could have a potential role in chemopreventive and chemotherapeutic treatment of hormonal breast and prostate cancers.     

Dietary isoflavones: biological effects and relevance to human health

Substantial evidence indicates that diets high in plant-based foods may explain the epidemiologic variance of many hormone-dependent diseases that are a major cause of mortality and morbidity in Western populations. There is now an increased awareness that plants contain many phytoprotectants. Lignans and isoflavones represent two of the main classes of phytoestrogens of current interest in clinical nutrition. Although ubiquitous in their occurrence in the plant kingdom, these bioactive nonnutrients are found in particularly high concentrations in flaxseeds and soybeans and have been found to have a wide range of hormonal and nonhormonal activities that serve to provide plausible mechanisms for the potential health benefits of diets rich in phytoestrogens. Data from animal and in vitro studies provide convincing evidence for the potential of phytoestrogens in influencing hormone-dependent states; although the clinical application of diets rich in these estrogen mimics is in its infancy, data from preliminary studies suggest beneficial effects of importance to health. This review focuses on the more recent studies pertinent to this field and includes, where appropriate, the landmark and historical literature that has led to the exponential increase in interest in phytoestrogens from a clinical nutrition perspective.     

Orally administered isoflavones are present as glucuronides in the human prostate

Better knowledge of the bioavailability and metabolism of isoflavones in prostate tissue is needed to further investigate their mechanisms of action in the context of prostate cancer prevention. A total of 12 men with benign prostatic hyperplasia received soy extract supplementation (3 Evestrel capsules, providing a total of 112.5 mg isoflavones aglycone eq/day) for 3 days before prostate surgery. Blood and prostate tissues were sampled and metabolites were identified using electrospray ionization liquid chromatography tandem mass spectrometry (LC-ESI-MS/MS) and chemically synthesized standards of glucuronidated isoflavones. The main metabolites were the same in prostate tissue and in plasma, namely, 2 monoglucuronides of daidzein and 2 monoglucuronides of genistein. Concentrations of total isoflavones measured in prostate reached 1.05 +/- 0.62 nmol/g tissue (range 0.30-2.23) at the time of sampling, 12 h after the last isoflavone supplementation. At that time point, prostate concentrations were lower than plasma concentrations in all volunteers: 0.47 nmol/g vs. 0.66 microM for daidzein and 0.58 nmol/g vs. 0.78 microM for genistein. Isoflavone mechanisms of action should thus be investigated in in vitro cell studies using physiological conditions, intracellular concentrations below 5 nmol/g and no intracellular deconjugation of the monoglucuronide metabolites.     

Differential effects of isoflavones, from Astragalus membranaceus and Pueraria thomsonii, on the activation of PPARalpha, PPARgamma, and adipocyte differentiation in vitro

Compounds that target the peroxisome proliferator-activated receptors PPARalpha and PPARgamma are used to correct dyslipidemia and to restore glycemic balance, respectively. Because the majority of diabetic patients suffer from atherogenic lipid abnormalities, in addition to insulin resistance, ligands are required that can activate both PPARalpha and PPARgamma. In this study, we used chimeric PPARalpha/gamma reporter-gene bioassays to screen herbal extracts with purported antidiabetic properties. Extracts of Astragalus membranaceus and Pueraria thomsonii significantly activated PPARalpha and PPARgamma. Bioassay-guided fractionation resulted in the isolation of the isoflavones, formononetin, and calycosin from Astragalus membranaceus, and daidzein from Pueraria thomsonii as the PPAR-activating compounds. We investigated the effects of these and 2 common isoflavones, genistein and biochanin A, using chimeric and full-length PPAR constructs in vitro. Biochanin A and formononectin were potent activators of both PPAR receptors (EC50 = 1-4 micromol/L) with PPARalpha/PPARgamma activity ratios of 1:3 in the chimeric and almost 1:1 in the full-length assay, comparable to those observed for synthetic dual PPAR-activating compounds under pharmaceutical development. There was a subtle hierarchy of PPARalpha/gamma activities, indicating that biochanin A, formononetin, and genistein were more potent than calycosin and daidzein in chimeric as well as full-length receptor assays. At low doses, only biochanin A and formononetin, but not genistein, calycosin, or daidzein, activated PPARgamma-driven reporter-gene activity and induced differentiation of 3T3-L1 preadipocytes. Our data suggest the potential value of isoflavones, especially biochanin A and their parent botanicals, as antidiabetic agents and for use in regulating lipid metabolism.     

人脐静脉血管内皮细胞的体外培养及rhNDPK-A对其增殖的作用

目的：建立一种体外培养人脐静脉血管内皮细胞的方法，初步探讨rhNDPK-A蛋白对内皮细胞生长的影响。方法：采用胶原酶对新生儿脐带静脉血管进行消化，从中分离出血管内皮细胞，体外传代培养，通过MTS／PMS法测定不同浓度的rhNDPK-A蛋白对HUVEC体外增殖的影响。结果：成功获得体外培养的人脐静脉血管内皮细胞，从0．0610μg／m1到250μg／ml的rhNDPK-A蛋白对人脐静脉血管内皮细胞的增殖既没有抑制也没有促进作用。结论：建立了分离培养人脐静脉向管内皮细胞的方法，rhNDPK-A蛋白不是通讨抑制内皮血管细胞的增殖而抑制血管新生的。     

Anti-inflammatory effects of insulin

PURPOSE OF REVIEW: This review deals with the recent observations on the pro-inflammatory effects of glucose and the anti-inflammatory actions of insulin. Apart from being novel, they are central to our understanding of why hyperglycemia is a prognosticator of bad clinical outcomes including patients with acute coronary syndromes, stroke and in patients in the intensive care unit. RECENT FINDINGS: The pro-inflammatory effect of glucose as well as that of other macronutrients including fast food meals provides the basis of chronic oxidative stress and inflammation in the obese and their propensity to atherosclerotic disease. The anti-inflammatory action of insulin provides a neutralizing effect to balance macronutrient induced inflammation on the one hand and the possibility of using insulin as an anti-inflammatory drug on the other. SUMMARY: The actions of macronutrients and insulin described above explain why insulin resistant states like obesity and type 2 diabetes are associated with oxidative stress, inflammation and atherosclerosis. They also suggest that insulin may be antiatherogenic.     

Early exposure to soy isoflavones and effects on reproductive health: a review of human and animal studies

Soy isoflavones are phytoestrogens with potential hormonal activity due to their similar chemical structure to 17-β-estradiol. The increasing availability of soy isoflavones throughout the food supply and through use of supplements has prompted extensive research on biological benefits to humans in chronic disease prevention and health maintenance. While much of this research has focused on adult populations, infants fed soy protein based infant formulas are exposed to substantial levels of soy isoflavones, even when compared to adult populations that consume a higher quantity of soy-based foods. Infant exposure, through soy formula, primarily occurs from birth to one year of life, a stage of development that is particularly sensitive to dietary and environmental compounds. This has led investigators to study the potential hormonal effects of soy isoflavones on later reproductive health outcomes. Such studies have included minimal human data with the large majority of studies using animal models. This review discusses key aspects of the current human and animal studies and identifies critical areas to be investigated as there is no clear consensus in this research field.     

有机酸对人血管内皮细胞的保护作用

目的：探讨氯原酸（CHA）、抗坏血酸（AA）、柠檬酸（CA）和苹果酸（MA）4种有机酸对人血管内皮细胞的保护作用。方法：通过人脐静脉内皮细胞培养,从形态、生长状况和乳酸脱氢酶（LDH）释放方面,观察预先4h、与oxLDL同时加入、加oxLDL3h后加入有机酸3种情况,以及3个不同剂量（10、20、40mg/L)的有机酸＋oxLDL(100mg/L)对内皮细胞的作用。结果:oxLDL对内皮细胞具有明显的损伤作用,细胞生存率低于正常对照组,LDH释放率高于正常组。预先和同时加入CAH、AA、CA、和MA各组对oxLDL引起的内皮细胞损伤具有不同程度的保护作用,而后加入有机酸各组对oxLDL引起的内皮细胞损伤没有影响。3个剂量的CHA和AA＋oxLDL各组,以及CA和MA＋oxLDL的高剂量组的细胞生存率均高于oxLDL组,LDH释放率均低于ocxLDL组,呈明显的剂量效应关系。结论、氯原酸、抗坏血酸、柠檬酸和苹果酸4种有机酸对oxLDL诱导的内皮细胞损伤具有不同程度的预防性保护作用,其中以氯原酸和抗坏血酸的作用最佳,柠檬酸次之,苹果酸最终。     

环氧合酶-2对人膀胱移行细胞癌血管内皮生长因子及血管形成的影响

目的 探讨环氧合酶-2(cox-2)对人膀胱移行细胞癌(BTCC)血管内皮生长因子(VEGF)及血管生成的影响.方法 应用免疫组化染色技术检测61例BTCC和7例正常膀胱组织中cox-2、VEGF的表达和微血管密度(MVD).结果 COX-2主要集中在肿瘤细胞胞质内,阳性表达率为55.74%(34/61),VEGF阳性表达率为59.02%(36/61),两者在正常膀胱组织中没有表达,COX-2、VEGF的表达强度与肿瘤的病理分级和分期有关.cox-2与VEGF的表达显著相关(r_s＝ 0.563,P＜0.01).cox-2与VEGF均阳性的膀胱癌组织MVD为76.45±20.60,明显高于两者均阴性者的38.29±15.05,差异有统计学意义(P＜0.01).结论 COX-2与VEGF在人BTCC组织中表达增高,表达强度与肿瘤的分级和分期有关.COX-2可能通过诱导VEGF表达而促进BTCC血管形成.     

The effects of short-chain fatty acids on human colon cancer cell phenotype are associated with histone hyperacetylation

The short-chain fatty acid (SCFA) butyrate is produced via anaerobic bacterial fermentation within the colon and is thought to be protective in regard to colon carcinogenesis. Although butyrate (C4) is considered the most potent of the SCFA, a variety of other SCFA also exist in the colonic lumen. Butyrate is thought to exert its cellular effects through the induction of histone hyperacetylation. We sought to determine the effects of a variety of the SCFA on colon carcinoma cell growth, differentiation and apoptosis. HT-29 or HCT-116 (wild-type and p21-deleted) cells were treated with physiologically relevant concentrations of various SCFA, and histone acetylation state was assayed by acid-urea-triton-X gel electrophoresis and immunoblotting. Growth and apoptotic effects were studied by flow cytometry, and differentiation effects were assessed using transient transfections and Northern blotting. Propionate (C3) and valerate (C5) caused growth arrest and differentiation in human colon carcinoma cells. The magnitude of their effects was associated with a lesser degree of histone hyperacetylation compared with butyrate. Acetate (C2) and caproate (C6), in contrast, did not cause histone hyperacetylation and also had no appreciable effects on cell growth or differentiation. SCFA-induced transactivation of the differentiation marker gene, intestinal alkaline phosphatase (IAP), was blocked by histone deacetylase (HDAC), further supporting the critical link between SCFA and histones. Butyrate also significantly increased apoptosis, whereas the other SCFA studied did not. The growth arrest induced by the SCFA was characterized by an increase in the expression of the p21 cell-cycle inhibitor and down-regulation of cyclin B1 (CB1). In p21-deleted HCT-116 colon cancer cells, the SCFA did not alter the rate of proliferation. These data suggest that the antiproliferative, apoptotic and differentiating properties of the various SCFA are linked to the degree of induced histone hyperacetylation. Furthermore, SCFA-mediated growth arrest in colon carcinoma cells requires the p21 gene.     

Anabolic effects of growth hormone in obese diet-restricted subjects are dose dependent

In previous studies growth hormone (GH) injections [0.1 mg/kg ideal body wt (IBW) every other day] produced significant increases in plasma insulin-like growth factor I (IGF-I) concentrations and nitrogen retention, which were attenuated when 12 kcal/kg IBW was ingested. The present study was done to determine whether doubling the GH dose would enhance its anabolic effects and facilitate fat loss. Eight women (33-83% over IBW) were fed 12 kcal/kg IBW for 14 wk. They received GH or vehicle injections, each for 5 wk during either weeks 2-6 or 9-13. GH improved nitrogen balance (GH, 3.6 +/- 123.2 mmol/d; vehicle, -132.0 +/- 117.9 mmol/d; means +/- SD; p less than 0.001). Plasma IGF-I increased from 32.1 +/- 9.6 to 79.4 +/- 22.1 nmol/L by day 5 of GH (p less than 0.001) and remained elevated until GH injections were discontinued. No significant effect of GH on mean body fat loss was observed. GH can induce significant anabolic responses even when caloric intake is decreased to 12 kcal/kg IBW. The degree and duration of these anabolic responses are dependent on the GH dose given.     

Soy isoflavones attenuate human monocyte adhesion to endothelial cell-specific CD54 by inhibiting monocyte CD11a

Soy-based diets have been shown to protect against the development of atherosclerosis; however, the underlying mechanism(s) remain unknown. Interaction between activated monocytes and inflamed endothelial cells is an early event in atherogenesis. Therefore, we examined whether treatment of monocytes with soy phytochemicals could inhibit their adhesion to the endothelial cell-specific protein, CD54, a key factor in monocyte adhesion. Female Sprague-Dawley rats were fed AIN-93G diets containing soy protein isolate or casein. Sera from soy-fed rats inhibited CD54-dependent monocyte adhesion, whereas sera from casein-fed rats did not. To determine whether isoflavones in the sera of soy-fed rats were involved in this inhibition, monocytes were preincubated with soy isoflavones. Isoflavone treatment inhibited monocyte adhesion to CD54 protein, as well as to endothelial cells expressing CD54. Monocyte expression of CD11a, the cognate receptor for CD54, was unaffected by isoflavones. However, binding of the activation epitope-specific antibody mAb24, which binds specifically to the active form of CD11a, was significantly lower in soy isoflavone-treated monocytes than in media-treated cells. These findings suggest that inhibition of CD54-dependent monocyte adhesion by soy isoflavones is mediated in part by affinity regulation of CD11a. Inhibition of monocyte adhesion to endothelial cells by isoflavones resulted in reduced expression of the inflammatory cytokines IL-6 and IL-8. Collectively, these data suggest that the athero-protective effect of soy diets may be mediated by blocking monocyte-endothelial cell interaction.