Secoisolariciresinol diglucoside: relevance to angiogenesis and cardioprotection against ischemia-reperfusion injury

Heterogeneous nuclear ribonucleoprotein U-actin complex derived from extracellular vesicles facilitates proliferation and migration of human coronary artery endothelial cells by promoting RNA polymerase II transcription

Coronary artery disease (CAD) represents a fatal public threat. The involvement of extracellular vesicles (EVs) in CAD has been documented. This study explored the regulation of embryonic stem cells (ESCs)-derived EVs-hnRNPU-actin complex in human coronary artery endothelial cell (HCAEC) growth. Firstly, in vitro HCAEC hypoxia models were established. EVs were extracted from ESCs by ultracentrifugation. HCAECs were treated with EVs and si-VEGF for 24 h under hypoxia, followed by assessment of cell proliferation, apoptosis, migration, and tube formation. Uptake of EVs by HCAECs was testified. Additionally, hnRNPU, VEGF, and RNA Pol II levels were determined using Western blotting and CHIP assays. Interaction between hnRNPU and actin was evaluated by Co-immunoprecipitation assay. HCAEC viability and proliferation were lowered, apoptosis was enhanced, wound fusion was decreased, and the number of tubular capillary structures was reduced under hypoxia, whereas ESC-EVs treatment counteracted these effects. Moreover, EVs transferred hnRNPU into HCAECs. EVs-hnRNPU-actin complex increased RNA Pol II level on the VEGF gene promoter and promoted VEGF expression in HCAECs. Inhibition of hnRNPU or VEGF both annulled the promotion of EVs on HCAEC growth. Collectively, ESC-EVs-hnRNPU-actin increased RNA Pol II phosphorylation and VEGF expression, thus promoting HCAEC growth.

Hypocholesterolemic Efficacy of Secoisolariciresinol Diglucoside and Its Polymer in Rat

Hypercholesterolemia is a risk factor for cardiovascular disease. Conventional treatment methods include lifestyle changes and pharmaceutical interventions, but recently Health Canada approved a health claim for whole ground flaxseed as an alternative treatment for hypercholesterolemia. The literature suggests flaxseed lignans are responsible for the cholesterol-reducing effects of flaxseed. In this study, 96.1% secoisolariciresinol diglucoside (SDG) and a 50% SDG enriched polymer (SDG polymer) were investigated as treatments for hypercholesterolemia in rats. Wistar female rats were fed a 1% high-cholesterol diet for a one-week acclimatization prior to a 23-day intervention with enriched SDG or SDG polymer. A reduction in body weight normalized liver weight was observed in rats treated with enriched SDG when compared to the controls. Both enriched SDG (96.1%) and SDG polymer reduced serum triacylglycerol (19% and 15%, respectively) and increased high-density lipoprotein cholesterol (15% and 24%, respectively). Histopathologic analyses revealed lipid-lowering effects of either enriched SDG or SDG polymer along with lower steatosis scores and nonalcoholic fatty liver disease activity. Furthermore, the lack of statistical significance between SDG and SDG polymer treatment groups suggests that SDG polymer may be a potential alternative to enriched SDG for hypercholesterolemia with similar efficacy but lower cost.

Protective Role of Polyphenols in Heart Failure: Molecular Targets and Cellular Mechanisms Underlying Their Therapeutic Potential

Heart failure (HF) is a leading cause of death in the United States, with a 5-year mortality rate of 50% despite modern pharmacological therapies. Plant-based diets are comprised of a diverse polyphenol profile, which lends to their association with reduced cardiovascular disease risk. Whether a polyphenol-rich diet can slow the progression of or reverse HF in humans is not known. To date, in vitro and in vivo studies have reported on the protective role of polyphenols in HF. In this review, we will discuss the major mechanisms by which polyphenols mitigate HF in vitro and in vivo, including (1) reduced cardiac inflammation and oxidative stress, (2) reduced mitochondrial dysfunction, (3) improved Ca²⁺ homeostasis, (4) increased survival signaling, and (5) increased sirtuin 1 activity.

Secoisolariciresinol Diglucoside Exerts Anti-Inflammatory and Antiapoptotic Effects through Inhibiting the Akt/IκB/NF-κB Pathway on Human Umbilical Vein Endothelial Cells

Inflammation is a key regulator in the progression of atherosclerosis (AS) which extremely affects people's health. Secoisolariciresinol diglucoside (SDG), a plant lignan, is relevant to angiogenesis and cardioprotection against ischemia-reperfusion injury and improves vascular disorders. However, the effect of SDG on cardiovascular disorder is not clear. In the present study, we aimed to investigate the effects of SDG on lipopolysaccharide- (LPS-) stimulated Human Umbilical Vein Endothelial Cells (HUVECs) and elucidate the underlying mechanism. The LPS-stimulated HUVEC cellular model was established. The cell viability, the cell tube formation activity, the nitric oxide (NO) release, the levels of inflammatory cytokine interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), the activation of nuclear factor kappa-B (NF-κB) pathway, and the expression of protein kinase B (Akt) were determined using Cell Counting Kit-8, cell tube-formation assay, western blotting, and enzyme-linked immunosorbent assay. Our results revealed that SDG reduces the angiogenic capacity of HUVECs and inhibited LPS-mediated HUVEC injury and apoptosis. In addition, SDG increased NO release and decreased the levels of IL-1β, IL-6, and TNF-α in LPS-treated HUVECs. Meanwhile, SDG inhibited the NF-κB pathway and downregulated Akt expression in LPS-induced HUVECs. Our results indicated that SDG relieves LPS-mediated HUVEC injury by inhibiting the NF-κB pathway which is partly dependent on the disruption of Akt activation. Therefore, SDG exerts its cytoprotective effects in the context of LPS-treated HUVECs via regulation of the Akt/IκB/NF-κB pathway and may be a potential treatment drug for cardiovascular disease.

Beyond Metabolism: The Complex Interplay Between Dietary Phytoestrogens, Gut Bacteria, and Cells of Nervous and Immune Systems

The human body has a large, diverse community of microorganisms which not only coexist with us, but also perform many important physiological functions, including metabolism of dietary compounds that we are unable to process ourselves. Furthermore, these bacterial derived/induced metabolites have the potential to interact and influence not only the local gut environment, but the periphery via interaction with and modulation of cells of the immune and nervous system. This relationship is being further appreciated every day as the gut microbiome is researched as a potential target for immunomodulation. A common feature among inflammatory diseases including relapsing-remitting multiple sclerosis (RRMS) is the presence of gut microbiota dysbiosis when compared to healthy controls. However, the specifics of these microbiota-neuro-immune system interactions remain unclear. Among all factors, diet has emerged as a strongest factor regulating structure and function of gut microbial community. Phytoestrogens are one class of dietary compounds emerging as potentially being of interest in this interaction as numerous studies have identified depletion of phytoestrogen-metabolizing bacteria such as Adlercreutzia, Parabacteroides and Prevotella in RRMS patients. Additionally, phytoestrogens or their metabolites have been reported to show protective effects when compounds are administered in the animal model of MS, Experimental Autoimmune Encephalomyelitis (EAE). In this review, we will illustrate the link between MS and phytoestrogen metabolizing bacteria, characterize the importance of gut bacteria and their mechanisms of action in the production of phytoestrogen metabolites, and discuss what is known about the interactions of specific compounds with cells immune and nervous system. A better understanding of gut bacteria-mediated phytoestrogen metabolism and mechanisms through which these metabolites facilitate their biological actions will help in development of novel therapeutic options for MS as well as other inflammatory diseases.

Dietary flaxseed protects against ventricular arrhythmias and left ventricular dilation after a myocardial infarction

Dietary omega-3 polyunsaturated fatty acids (n-3 PUFAs) have been associated with a lower incidence of cardiovascular events and sudden cardiac death. Flaxseed is a rich plant source of n-3 PUFAs and can retard the progression and accelerate the regression of atherosclerotic plaques. The aim of the study was to examine the preventive and therapeutic effects of dietary flaxseed on arrhythmias and heart dysfunction that develops after a myocardial infarction (MI). The left anterior descending coronary artery was ligated in rats to induce the MI. Rats were randomized into five groups: sham MI with normal chow, MI with normal chow, MI with 10% milled flaxseed supplementation (flax), MI with 4.4% supplemented flax oil enriched in alpha-linolenic acid (ALA) and MI with flax lignan secoisolariciresinol diglucoside (SDG) supplementation (0.44%). Animals were fed with their respective diets for 2 weeks before and for 8 weeks after the surgery. Echocardiography and continuous electrocardiographic recordings were obtained after ligation to confirm the induction of the MI, to check for arrhythmias and to assess cardiac function. Histological examination was also performed to evaluate cardiac fibrosis. Dietary supplementation with flaxseed, ALA or SDG before and after the induction of the MI significantly reduced the incidence of arrhythmias and resulted in significantly smaller infarct size, less left ventricle dilation, and decreased myocardial fibrosis and tumor necrosis factor-α levels compared to the control MI group. Together, this study supports a beneficial effect of dietary flaxseed in patients for the prevention and treatment of arrhythmias and ventricular remodeling post-MI.

Secoisolariciresinol diglucoside prevents the oxidative stress-induced apoptosis of myocardial cells through activation of the JAK2/STAT3 signaling pathway

Myocardial cell apoptosis mediated by oxidative stress has previously been identified as a key process in ischemic heart disease. Secoisolariciresinol diglucoside (SDG), a polyphenolic plant lignan primarily found in flaxseed, has been demonstrated to effectively protect myocardial cells from apoptosis. In the present study, the role of the Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) was investigated in mediating the protective effect of SDG. Findings of the present study revealed that treatment with H2O2 reduced cell viability and induced apoptosis in H9C2 rat cardiomyocytes. However, SDG was able to reduce the effect of H2O2 in a dose‑dependent manner. H2O2 reduced the expression level of phosphorylated STAT3 and inhibited the levels of B‑cell lymphoma‑extra‑large and induced myeloid leukemia cell differentiation protein, which are the STAT3 target genes. Conversely, SDG rescued phosphorylation of STAT3 and increased the levels of STAT3 target genes. Treatment with SDG alone led to a dose‑dependent increased phosphorylation of JAK2 and STAT3, without activating Src. Furthermore, the anti‑apoptotic effects of SDG were partially abolished by a JAK2/STAT3 inhibitor. In addition, molecular docking revealed that SDG may bind to the protein kinase domain of JAK2, at a binding energy of ‑8.258 kcal/mol. Molecular dynamics simulations revealed that JAK2‑SDG binding was stable. In conclusion, activation of the JAK2/STAT3 signaling pathway contributed to the anti‑apoptotic activity of SDG, which may be a potential JAK2 activator.

Flaxseed: its bioactive components and their cardiovascular benefits

Cardiovascular disease remains the leading cause of mortality and morbidity worldwide. The inclusion of functional foods and natural health products in the diet are gaining increasing recognition as integral components of lifestyle changes in the fight against cardiovascular disease. Several preclinical and clinical studies have shown the beneficial cardiovascular effects of dietary supplementation with flaxseed. The cardiovascular effects of dietary flaxseed have included an antihypertensive action, antiatherogenic effects, a lowering of cholesterol, an anti-inflammatory action, and an inhibition of arrhythmias. Its enrichment in the ω-3 fatty acid α-linolenic acid and the antioxidant lignan secoisolariciresinol diglucoside as well as its high fiber content have been implicated primarily in these beneficial cardiovascular actions. Although not as well recognized, flaxseed is also composed of other potential bioactive compounds such as proteins, cyclolinopeptides, and cyanogenic glycosides, which may also produce biological actions. These compounds could also be responsible for the cardiovascular effects of flaxseed. This article will not only summarize the cardiovascular effects of dietary supplementation with flaxseed but also review its bioactive compounds in terms of their properties, biological effects, and proposed mechanisms of action. It will also discuss promising research directions for the future to identify additional health-related benefits of dietary flaxseed.

Hemorheological effects of secoisolariciresinol in ovariectomized rats

BACKGROUND

Postmenopausal women often develop hemorheological disorders which may affect the systemic blood circulation and present a cardiovascular risk factor.

OBJECTIVE

We evaluated effects of secoisolariciresinol (SECO), a phytoestrogen, on hemorheological parameters and lipid peroxidation in a model of the age-related and/or surgical menopause induced by ovariectomy in rats.

METHODS

Arterial blood was sampled from sham-operated female rats, ovariectomized rats (OVX), and OVX treated with SECO (OVXSECO) (20 mg/kg/day intragastrically for two weeks). Plasma estrogen concentration and the following hemorheological parameters were measured: RBC aggregation (half-time of aggregation, T1/2; amplitude of aggregation, AMP; aggregation index, AI), RBC deformability (elongation index, EI), whole blood viscosity at the shear rate of 3-300 s-1, plasma viscosity, hematocrit, plasma fibrinogen. Lipid peroxidation was evaluated by measuring conjugated dienes (CD) and thiobarbituric acid reactive substances (TBARS) in plasma.

RESULTS

Ovariectomy in rats caused a 60% decrease in plasma estrogen level and triggered the development of macro- and microhemorheological abnormalities. Blood viscosity increased by 12-31%, RBC elongation index reduced by 16-28%, and T1/2 and AI increased by 35% and 29% respectively. The increase in blood viscosity correlated predominantly with reduced RBC deformability. Plasma CD and TBARS were elevated by 47% and 104% respectively. SECO therapy for OVX rats reduced blood viscosity by 9-18% and T1/2 by 32%, and increased EI by 4-17%. SECO therapy disrupted the correlation between blood viscosity and RBC deformability. Lipid peroxidation was significantly inhibited, as shown by the reduction in CD and TBARS plasma concentrations by 89% and 70% respectively. SECO did not affect plasma viscosity, estrogen or fibrinogen levels.

CONCLUSIONS

SECO treatment for OVX rats improves blood macro- and microrheological parameters, possibly through antioxidant protection of RBC.

Secoisolariciresinol diglucoside attenuates cardiac hypertrophy and oxidative stress in monocrotaline-induced right heart dysfunction

Pulmonary arterial hypertension (PAH) occurs when remodeling of pulmonary vessels leads to increased pulmonary vascular resistance resulting in increased pulmonary arterial pressure. Increased pulmonary arterial pressure results in right ventricle hypertrophy and eventually heart failure. Oxidative stress has been implicated in the pathogenesis of PAH and may play a role in the regulation of cellular signaling involved in cardiac response to pressure overload. Secoisolariciresinol diglucoside (SDG), a component from flaxseed, has been shown to reduce cardiac oxidative stress in various pathophysiological conditions. We investigated the potential protective effects of SDG in a monocrotaline-induced model of PAH. Five- to six-week-old male Wistar rats were given a single intraperitoneal injection of monocrotaline (60 mg/kg) and sacrificed 21 days later where heart, lung, and plasma were collected. SDG (25 mg/kg) was given via gavage as either a 21-day co-treatment or pre-treatment of 14 days before monocrotaline administration and continued for 21 days. Monocrotaline led to right ventricle hypertrophy, increased lipid peroxidation, and elevated plasma levels of alanine transaminase (ALT) and aspartate transaminase (AST). Co-treatment with SDG did not attenuate hypertrophy or ALT and AST levels but decreased reactive oxygen species (ROS) levels and catalase and superoxide dismutase activity compared to the monocrotaline-treated group. Pre-treatment with SDG decreased right ventricle hypertrophy, ROS levels, lipid peroxidation, catalase, superoxide dismutase, and glutathione peroxidase activity and plasma levels of ALT and AST when compared to the monocrotaline group. These findings indicate that pre-treatment with SDG provided better protection than co-treatment in this model of right heart dysfunction, suggesting an important role for SDG in PAH and right ventricular remodeling.

Urinary phytoestrogens and cancer, cardiovascular, and all-cause mortality in the continuous National Health and Nutrition Examination Survey

PURPOSE

Experimental studies suggest that phytoestrogen intake alters cancer and cardiovascular risk. This study investigated the associations of urinary phytoestrogens with total cancer (n = 79), cardiovascular (n = 108), and all-cause (n = 290) mortality among 5179 participants in the continuous National Health and Nutrition Examination Survey (1999-2004).

METHODS

Urinary phytoestrogens were measured using high-performance liquid chromatography with tandem mass spectrometric detection. Survival analysis was performed to evaluate hazard ratios (HRs) and 95 % confidence intervals (CIs) for each of the three outcomes in relation to urinary phytoestrogens.

RESULTS

After adjustment for confounders, higher urinary concentrations of total enterolignans were associated with a reduced risk of death from cardiovascular disease (HR for tertile 3 vs. tertile 1 0.48; 95 % CI 0.24, 0.97), whereas higher urinary concentrations of total isoflavones (HR for tertile 3 vs. tertile 1 2.14; 95 % CI 1.03, 4.47) and daidzein (HR for tertile 3 vs. tertile 1 2.05; 95 % CI 1.02, 4.11) were associated with an increased risk. A reduction in all-cause mortality was observed for elevated urinary concentrations of total enterolignans (HR for tertile 3 vs. tertile 1 0.65; 95 % CI 0.43, 0.96) and enterolactone (HR for tertile 3 vs. tertile 1 0.65; 95 % CI 0.44, 0.97).

CONCLUSIONS

Some urinary phytoestrogens were associated with cardiovascular and all-cause mortality in a representative sample of the US population. This is one of the first studies that used urinary phytoestrogens as biomarkers of their dietary intake to evaluate the effect of these bioactive compounds on the risk of death from cancer and cardiovascular disease.

Secoisolariciresinol diglucoside abrogates oxidative stress-induced damage in cardiac iron overload condition

Cardiac iron overload is directly associated with cardiac dysfunction and can ultimately lead to heart failure. This study examined the effect of secoisolariciresinol diglucoside (SDG), a component of flaxseed, on iron overload induced cardiac damage by evaluating oxidative stress, inflammation and apoptosis in H9c2 cardiomyocytes. Cells were incubated with 50 μ5M iron for 24 hours and/or a 24 hour pre-treatment of 500 μ M SDG. Cardiac iron overload resulted in increased oxidative stress and gene expression of the inflammatory mediators tumor necrosis factor-α, interleukin-10 and interferon γ, as well as matrix metalloproteinases-2 and -9. Increased apoptosis was evident by increased active caspase 3/7 activity and increased protein expression of Forkhead box O3a, caspase 3 and Bax. Cardiac iron overload also resulted in increased protein expression of p70S6 Kinase 1 and decreased expression of AMP-activated protein kinase. Pre-treatment with SDG abrogated the iron-induced increases in oxidative stress, inflammation and apoptosis, as well as the increased p70S6 Kinase 1 and decreased AMP-activated protein kinase expression. The decrease in superoxide dismutase activity by iron treatment was prevented by pre-treatment with SDG in the presence of iron. Based on these findings we conclude that SDG was cytoprotective in an in vitro model of iron overload induced redox-inflammatory damage, suggesting a novel potential role for SDG in cardiac iron overload.

Sodium tanshinone IIA sulfonate protects rat myocardium against ischemia-reperfusion injury via activation of PI3K/Akt/FOXO3A/Bim pathway

AIM

To investigate the mechanisms underlying the protective effects of sodium tanshinone IIA sulfonate (STS) in an ischemia-reperfusion (I/R)-induced rat myocardial injury model.

METHODS

Male SD rats were iv injected with STS, STS+LY294002 or saline (NS) for 15 d. Then the hearts were subjected to 30 min of global ischemia followed by 2 h of reperfusion. Cardiac function, infarction size and area at risk were assessed. Cell apoptosis was evaluated with TUNEL staining, DNA laddering and measuring caspase-3 activity. In addition, isolated cardiomyocytes of neonatal rats were pretreated with the above drugs, then exposed to H2O2 (200 mol/L) for 1 h. Cell apoptosis was detected using flow cytometric assay. The levels of p-Akt, p-FOXO3A and Bim were examined with immunoblotting.

RESULTS

Compared to NS group, administration of STS (20 mg/kg) significantly reduced myocardial infarct size (40.28%±5.36% in STS group vs 59.52%±7.28% in NS group), and improved the myocardial function as demonstrated by the increased values of dp/dtmax, LVDP and coronary flow at different reperfusion time stages. Furthermore, STS significantly decreased the rate of apoptotic cells (15.11%±3.71% in STS group vs 38.21%±7.83% in NS group), and reduced caspase-3 activity to nearly a quarter of that in NS group. Moreover, STS significantly increased the phosphorylation of Akt and its downstream target FOXO3A, and decreased the expression of pro-apoptotic gene Bim. Co-treatment with the PI3K inhibitor LY294002 (40 mg/kg) partially countered the protective effects induced by STS treatment. In isolated cardiomyocytes, STS exerted similar protective effects as shown in the ex vivo I/R model.

CONCLUSION

STS pretreatment reduces infarct size and improves cardiac function in an I/R-induced rat myocardial injury model via activation of Akt/FOXO3A/Bim-mediated signal pathway.

Cardioprotective activity of flax lignan concentrate extracted from seeds of Linum usitatissimum in isoprenalin induced myocardial necrosis in rats

The objective of the study was to evaluate the cardioprotective activity of flax lignan concentrate (FLC) in isoprenalin (ISO) induced cardiotoxicity in rats. Male Wistar rats (200–230 g) were divided into three groups. Group I: control, Group II: isoprenalin, Group III: FLC (500 mg/kg, p.o.) orally for 8 days and in group II and III isoprenalin 5.25 mg/kg, s.c. on day 9 and 8.5 mg/kg on day 10. On day 10 estimation of marker enzymes in serum and haemodynamic parameters were recorded. Animals were sacrificed, histology of heart was performed. Isoprenalin showed cardiotoxicity, manifested by increased levels of marker enzymes and increased heart rate. FLC treatment reversed these biochemical changes significantly compared with ISO group. The cardiotoxic effect of isoprenalin was less in FLC pretreated animals, which was confirmed in histopathological alterations. Haemodynamic, biochemical alteration and histopathological results suggest a cardioprotective protective effect of FLC in isoprenalin induced cardiotoxicity.

Dietary lignans: physiology and potential for cardiovascular disease risk reduction

The present review of the literature on lignan physiology and lignan intervention and epidemiological studies was conducted to determine if lignans decrease the risks of cardiovascular disease in Western populations. Five intervention studies using flaxseed lignan supplements indicated beneficial associations with C-reactive protein, and a meta-analysis that included these studies also suggested lignans have a lowering effect on plasma total and low-density lipoprotein cholesterol. Three intervention studies using sesamin supplements indicated possible lipid- and blood pressure-lowering associations. Eleven human observational epidemiological studies examined dietary intakes of lignans in relation to cardiovascular disease risk. Five showed decreased risk with either increasing dietary intakes of lignans or increased levels of serum enterolactone (an enterolignan used as a biomarker of lignan intake), five studies were of borderline significance, and one was null. The associations between lignans and decreased risk of cardiovascular disease are promising, but they are yet not well established, perhaps due to low lignan intakes in habitual Western diets. At the higher doses used in intervention studies, associations were more evident.

Health effects with consumption of the flax lignan secoisolariciresinol diglucoside

Flaxseed is the richest source of the lignan secoisolariciresinol diglucoside (SDG). After ingestion, SDG is converted to secoisolariciresinol, which is further metabolised to the mammalian lignans enterodiol and enterolactone. A growing body of evidence suggests that SDG metabolites may provide health benefits due to their weak oestrogenic or anti-oestrogenic effects, antioxidant activity, ability to induce phase 2 proteins and/or inhibit the activity of certain enzymes, or by mechanisms yet unidentified. Human and animal studies identify the benefits of SDG consumption. SDG metabolites may protect against CVD and the metabolic syndrome by reducing lipid and glucose concentrations, lowering blood pressure, and decreasing oxidative stress and inflammation. Flax lignans may also reduce cancer risk by preventing pre-cancerous cellular changes and by reducing angiogenesis and metastasis. Thus, dietary SDG has the potential to decrease the incidence of several chronic diseases that result in significant morbidity and mortality in industrialised countries. The available literature, though, makes it difficult to clearly identify SDG health effects because of the wide variability in study methods. However, the current evidence suggests that a dose of at least 500 mg SDG/d for approximately 8 weeks is needed to observe positive effects on cardiovascular risk factors in human patients. Flaxseed and its lignan extracts appear to be safe for most adult populations, though animal studies suggest that pregnant women should limit their exposure. The present review discusses the potential health benefits of SDG in humans, with supporting evidence from animal studies, and offers suggestions for future research.

Akt/FOXO3a/SIRT1-mediated cardioprotection by n-tyrosol against ischemic stress in rat in vivo model of myocardial infarction: switching gears toward survival and longevity

Moderate consumption of wine has been associated with decreased risk of cardiovascular events. Recently we have shown that white wine is equally as cardioprotective as red wine. However, unlike resveratrol (polyphenol in red wine), the white wine component, n-tyrosol [2-(4-hydroxyphenyl)ethanol] has not been explored for its cardioprotective effect and mechanism of action. Therefore, the present study was designed to evaluate the effect of tyrosol treatment (5 mg/kg/day for 30 days) on myocardial ischemic stress in a rat in vivo model of Myocardial Infarction (MI) and to identify key molecular targets involved in this mechanism. MI was induced by Left Anterior Descending (LAD) coronary artery ligation. Reduced infarct size (32.42 vs 48.03%) and cardiomyocyte apoptosis (171 vs 256 counts/100 HPF) were observed along with improvement in the myocardial functional parameters such as LVIDs (5.89 vs 6.58 mm), ejection fraction (51.91 vs 45.09%), and fractional shortening (28.46 vs 23.52%) as assessed by echocardiography in the tyrosol-treated animals when compared to the nontreated controls. We have also observed significant increase in the phosphorylation of Akt (1.4-fold), eNOS (3-fold) and FOXO3a (2.6-fold). In addition, tyrosol induced the expression of longevity protein SIRT1 (3.2-fold) in the MI group as compared to the non-treated MI control. Therefore tyrosol's SIRT1, Akt and eNOS activating power adds another dimension to the white wine research, because it adds a great link to the French paradox. In conclusion these findings suggest that tyrosol induces myocardial protection against ischemia related stress by inducing survival and longevity proteins that may be considered as anti-aging therapy for the heart. However, human intervention studies would be necessary before establishing any recommendations about dietary habits for tyrosol intake or administration of dietary supplements containing tyrosol.

White wine induced cardioprotection against ischemia-reperfusion injury is mediated by life extending Akt/FOXO3a/NFkappaB survival pathway

Recent studies on the protection afforded by moderate wine consumption against cardiovascular diseases have focused mainly on the activity of red wine in view of its high content of antioxidants, especially polyphenols. White wine lacks polyphenols, but it contains other compounds such as hydroxycinnamic acids (caffeic acid) and monophenols (tyrosol), which are known to have antioxidant properties. Therefore, this study was designed to examine the effect of white wine in myocardial ischemic-reperfusion injury. The experimental rats were gavaged with white wine (Soave Suavia "Le Rive" 2004) at a dosage of 6.5 mL/(kg.rat.day) for 30 days. Rats were divided into four groups: control sham (CS), wine-treated sham (WS), control ischemia (I)/reperfusion (R) (CIR), and wine + IR (WIR). All the rats in both IR groups underwent 30 min occlusion of the left anterior descending coronary artery followed by 8, 24 h, and 30 days of reperfusion (R). Significant reduction in infarct size (21 vs 39%, n = 6), cardiomyocyte (274 vs 384 counts/100 HPF, n = 6), and endothelial cell apoptosis (387 vs 587 counts/100 HPF) was observed in WIR as compared with CIR after 24 h of reperfusion. Echocardiography demonstrated significant increased fractional shortening (32 vs 22%) and ejection fraction (60 vs 44%) following 30 days of reperfusion in WIR rats compared to CIR ( n = 6). In addition, increased phosphorylation of AKT, Foxo3a, and eNOS were found in WS and WIR, as compared to their respective controls. The gel-shift analysis demonstrated significant upregulation of DNA binding activity of NF-kappaB in the white wine-treated groups. This report demonstrated for the first time that the white wine mediated cardioprotection in ischemic reperfused myocardium is through the PI-3kinase/Akt/FOXO3a/e-NOS/NF-kappaB survival pathway.

Adeno-sh-beta-catenin abolishes ischemic preconditioning-mediated cardioprotection by downregulation of its target genes VEGF, Bcl-2, and survivin in ischemic rat myocardium

beta-Catenin, the downstream target of glycogen synthase kinase-3beta (GSK-3beta), plays a vital role in ischemic preconditioning (IP)-mediated cardioprotection. In the present study, we investigated the mechanism of IP-mediated cardioprotection through suppression of beta-catenin expression by intramyocardial injection of adeno-sh-RNA against beta-catenin (BCT) (4 x 10(8) pfu). Adeno-LacZ (LZ) was used as control. The rats were randomized into (a) LZ + ischemia-reperfusion (IR); (b) LZIPIR; (c) BCTIR; and (d) BCTIPIR. Isolated hearts from each group were subjected to 30 min of I followed by 2 h of R. Both IPIR group hearts were subjected to IP (5 min I + 10 min R; four cycles) before IR. Significant reduction in left ventricular functional recovery (78 vs. 88 mm Hg), dp/dt(max) (1,802 vs. 2,189 mm Hg/sec), and aortic flow (4 vs. 9 ml/min) was observed in BCTIPIR compared with LZIPIR at 120 min of reperfusion. Increased infarct size (42 vs. 24%) and apoptotic cardiomyocytes (122 vs. 58 counts/60 HPF) were observed in BCTIPIR compared with LZIPIR. Realtime PCR and Western blot analysis showed significant downregulation in mRNA and protein expression of VEGF, Bcl-2, and survivin in BCTIPIR compared with LZIPIR. These findings indicated for the first time that silencing beta-catenin abolished IP-mediated cardioprotection, probably through inhibition of VEGF-Bcl-2 and survivin.

Upregulation of myocardial 11S-activated proteasome in experimental hyperglycemia

This study examined the hypothesis that the ubiquitin proteasome system (UPS) degrades proteins damaged by exposure to hyperglycemia. Experimental hyperglycemia was induced in male rats by treatment with streptozotocin. After 30 days, echocardiography confirmed the presence of cardiomyopathy as ejection fraction, fractional shortening, and diastolic function (E/A ratio) were decreased, and chamber diameter was increased in hyperglycemic animals. Proteasome non-ATP-dependent chymotryptic activity was increased over 2-fold in hyperglycemic hearts, but the ATP-dependent activity was decreased and levels of ubiquitinated proteins were increased. Protein levels of the PA28alpha of the 11S-activator ring were increased by 128% and the PA28beta subunit increased by 58% in the hyperglycemic hearts. The alpha3 subunit of the 20S-proteasome was increased by 82% while the catalytic beta5 subunit was increased by 68% in hyperglycemic hearts. Protein oxidation as indicated by protein carbonyls was significantly higher in hyperglycemic hearts. These studies support the conclusion that the UPS becomes dysfunctional during long term hyperglycemia. However, 11S-activated proteasome was increased suggesting a response to oxidative protein damage and a potential role for this form of the proteasome in a cardiac pathophysiology.

Secoisolariciresinol diglucoside induces neovascularization-mediated cardioprotection against ischemia-reperfusion injury in hypercholesterolemic myocardium

Hypercholesterolemia (HC) induced endothelial cell dysfunction and decreased endothelial nitric oxide formation results in impaired angiogenesis and subsequent cardiovascular disorders. Therapeutic angiogenesis is known to be a novel strategy for treatment of patients with ischemic heart disease. We have shown that secoisolariciresinol diglucoside (SDG) is angiogenic as well as cardioprotective against myocardial ischemia. In the present study, we examined the efficacy of SDG in a hypercholesterolemic myocardial infarction (MI) model. The rats were maintained on a normal and high cholesterol diet (2%) for 8 weeks followed by oral administration of SDG (20 mg/kg) for 2 weeks. The rats were divided into four groups (n=24 in each): Control (C); SDG control (SDG); HC; and HC+SDG (HSDG). Isolated hearts subjected to 30 min of global ischemia followed by 120 min of reperfusion were used to measure the cardiac functions, infarct size and to examine the protein expression profile. After treatment, MI was induced by ligating the left anterior descending artery. Echocardiographic parameters were examined 30 days after MI. Significant reduction in total cholesterol, LDL-cholesterol, triglycerides and an increase in HDL-cholesterol levels were observed in HSDG as compared to the HC. Decreased infarct size was observed in the HSDG group (43%) compared to the HC (54%). Increased phosphorylation of endothelial nitric oxide synthase (p-eNOS) (3.1-fold), vascular endothelial growth factor (1.9-fold) and heme oxygenase-1 (2.3-fold) was observed in the HSDG group as compared to the HC group. Significant improvement in left ventricular functions was also observed in the HSDG group as evidenced by increased ejection fraction (55% vs. 45%), fractional shortening (28% vs. 22%) and decreased left ventricular inner diameter in systole (8 vs. 6 mm) in HSDG compared to HC. Moreover, MI model has shown increased capillary density (2531 vs. 1901) and arteriolar density (2.6 vs. 1.8) in SDG-treated rats as compared to the HC. The increased capillary and arteriolar density along with increased left ventricular functions on SDG treatment might be due to increased HO-1, VEGF and p-eNOS expression. In conclusion, our study demonstrates for the first time that SDG treatment reduces ventricular remodeling by neovascularization of the infarcted HC myocardium.