Resveratrol supplementation abrogates pro-arteriogenic effects of intramyocardial vascular endothelial growth factor in a hypercholesterolemic swine model of chronic ischemia

Potential of plant polyphenols to combat oxidative stress and inflammatory processes in farm animals

Polyphenols are secondary plant metabolites which have been shown to exert antioxidative and antiinflamma tory effects in cell culture, rodent and human studies. Based on the fact that conditions of oxidative stress and inflammation are highly relevant in farm animals, polyphenols are considered as promising feed additives in the nutrition of farm animals. However, in contrast to many studies existing with model animals and humans, potential antioxidative and antiinflammatory effects of polyphenols have been less investigated in farm animals so far. This review aims to give an overview about potential antioxidative and antiinflammatory effects in farm animals. The first part of the review highlights the occurrence and the consequences of oxidative stress and inflammation on animal health and performance. The second part of the review deals with bioavailability and metabolism of polyphenols in farm animals. The third and main part of the review presents an overview of the findings from studies which investigated the effects of polyphenols of various plant sources in pigs, poultry and cattle, with particular consideration of effects on the antioxidant system and inflammation.

Modified VEGF targets the ischemic myocardium and promotes functional recovery after myocardial infarction

Vascular endothelial growth factor (VEGF) promotes angiogenesis and improves cardiac function after myocardial infarction (MI). However, the non-targeted delivery of VEGF decreases its therapeutic efficacy due to an insufficient local concentration in the ischemic myocardium. In this study, we used a specific peptide to modify VEGF and determined that this modified VEGF (IMT-VEGF) localized to the ischemic myocardium through intravenous injection by interacting with cardiac troponin I (cTnI). When IMT-VEGF was used to mediate cardiac repair in a rat model of ischemia-reperfusion (I-R) injury, we observed a decreased scar size, enhanced angiogenesis and improved cardiac function. Moreover, an alternative treatment using the repeated administration of a low-dose IMT-VEGF also promoted angiogenesis and functional recovery. The therapeutic effects of IMT-VEGF were further confirmed in a pig model of MI as the result of the conserved properties of its interacting protein, cTnI. These results suggest a promising therapeutic strategy for MI based on the targeted delivery of IMT-VEGF.

Resveratrol and grape juice differentially ameliorate cardiovascular autonomic modulation in L-NAME-treated rats

Polyphenols consumption detected in red wine and grape juice may prevent or help in the treatment of hypertension. However, cardiovascular autonomic effects of polyphenols were poorly studied. Therefore, we evaluated the effects of resveratrol and grape juice treatments in hemodynamics, baroreflex sensitivity, heart rate (HR) and blood pressure (BP) variability and cardiac redox parameters. Male Wistar rats were divided in 3 groups (n=7/each) and treated for 30 days: only L-NAME-treated (60 mg/kg/day by oral gavage), L-NAME+resveratrol (L-NAME+R) and L-NAME+grape juice (L-NAME+G). BP signal was directly recorded and pulse interval (PI) and systolic arterial pressure (SAP) variability were analyzed in time and frequency domains. Baroreflex sensitivity (BRS) was determined by the alpha index. Oxidized and reduced glutathione concentrations were determined in cardiac tissue. L-NAME increased BP with no differences among groups (mean BP: L-NAME=124±4, L-NAME+R=126±3 and L-NAME+G=125±4 mmHg). PI and SAP variability expressed by total variance were also similar among groups. However, normalized low frequency (LF) and high frequency (HF) components of PI variability were lower and higher, respectively, in both R and G-treated groups when compared to only L-NAME group. Interestingly, sympathetic modulation to the vessels (LF from SAP variability) and BRS were decreased and increased, respectively, only in L-NAME+R rats. Additionally, GSH/GSSG ratios were higher in L-NAME+R and L-NAME+G than in L-NAME group. Our results indicate that resveratrol and grape juice treatments can modulate autonomic function and promote cardiac redox benefits even when nitric oxide is decreased. Moreover, resveratrol influences not only cardiac but also vascular autonomic modulation.

Resveratrol ameliorates high-glucose-induced hyperpermeability mediated by caveolae via VEGF/KDR pathway

Endothelial hyperpermeability induced by hyperglycemia is the initial step in the development of atherosclerosis, one of the most serious cardiovascular complications in diabetes. In the present study, we investigated the effects of resveratrol (RSV), a bioactive ingredient extracted from Chinese herb rhizoma polygonum cuspidatum, on permeability in vitro and the molecular mechanisms involved. Permeability was assessed by the efflux of fluorescein isothiocyanate (FITC)-dextran permeated through the monolayer endothelial cells (ECs). The mRNA levels, protein expressions, and secretions were measured by quantitative real-time PCR, western blot, and ELISA, respectively. Increased permeability and caveolin-1 (cav-1) expression were observed in monolayer ECs exposed to high glucose. Resveratrol treatment alleviated the hyperpermeability and the overexpression of cav-1 induced by high glucose in a dose-dependent manner. β-Cyclodextrin, a structural inhibitor of caveolae, reduced the hyperpermeability caused by high glucose. Resveratrol also down-regulated the increased expressions of vascular endothelial growth factor (VEGF) and kinase insert domain receptor (KDR, or VEGF receptor-2) induced by high glucose. Inhibition of VEGF/KDR pathway by using SU5416, a selective inhibitor of KDR, alleviated the hyperpermeability and the cav-1 overexpression induced by high glucose. The above results demonstrate that RSV ameliorates caveolae-mediated hyperpermeability induced by high glucose via VEGF/KDR pathway.

Cardioprotective effects of red wine and vodka in a model of endothelial dysfunction

BACKGROUND

Moderate alcohol consumption is largely believed to be cardioprotective, while red wine is hypothesized to offer benefit in part due to the proangiogenic and antioxidant properties of polyphenols. We investigated the cardiovascular effects of both red wine and vodka in a swine model of endothelial dysfunction.

METHODS

Twenty-seven male Yorkshire swine fed a high-fat/cholesterol diet were divided into three groups and received either no alcohol (Control), red wine, or vodka. After 7 wk, myocardial perfusion was measured, and ventricular tissue was analyzed for microvascular reactivity and immunohistochemical studies.

RESULTS

There were no differences in myocardial perfusion, in arteriolar or capillary density, or in VEGF expression among groups. Total protein oxidation as well as expression of superoxide dismutase-1 and -2 and NADPH oxidase was decreased in both treatment groups compared to controls. Endothelium-dependent microvessel relaxation, however, was significantly improved only in the red wine-supplemented group.

CONCLUSIONS

Supplementation with both red wine and vodka decreased oxidative stress by several measures, implicating the effects of ethanol in reducing oxidative stress in the myocardium. However, it was only in the red wine-supplemented group that an improvement in microvessel function was observed. This suggests that a component of red wine, independent of ethanol, possibly a polyphenol such as resveratrol, may confer cardioprotection by normalizing endothelial dysfunction induced by an atherogenic diet.

Overfed Ossabaw swine with early stage metabolic syndrome have normal coronary collateral development in response to chronic ischemia

Ossabaw miniswine have been naturally selected to efficiently store large amounts of lipids offering them a survival advantage. Our goal was to evaluate the myocardial response to chronic ischemia of the Ossabaw consuming a hypercaloric, high-fat/cholesterol diet with and without metformin supplementation. At 6 weeks of age animals were fed either a regular diet (OC, n = 9), a hypercaloric high-fat/cholesterol diet (OHC, n = 9), or a hypercaloric high-fat/cholesterol diet supplemented with metformin (OHCM, n = 8). At 9 weeks, all animals underwent ameroid constrictor placement to the left circumflex coronary artery to simulate chronic ischemia. Seven weeks after ameroid placement, all animals underwent hemodynamic and functional measurements followed by cardiac harvest. Both OHC and OHCM animals developed significantly greater weight gain, total cholesterol, and LDL:HDL ratio compared to OC controls. Metformin administration reversed diet-induced hypertension and glucose intolerance. There were no differences in global and regional contractility, myocardial perfusion, capillary and arteriolar density, or total protein oxidation between groups. Myocardial protein expression of VEGF, PPAR-α, γ, and δ was significantly increased in the OHC and OHCM groups. Microvessel reactivity was improved in the OHC and OHCM groups compared to controls, and correlated with increased p-eNOS expression. Overfed Ossabaw miniswine develop several components of metabolic syndrome. However, impairments of myocardial function, neovascularization and perfusion were not present, and microvessel reactivity was paradoxically improved in hypercholesterolemic animals. The observed cardioprotection despite metabolic derangements may be due to lipid-dependant upregulation of the PPAR pathway which is anti-inflammatory and governs myocardial fatty acid metabolism.