Red wine prevents homocysteine-induced endothelial dysfunction in porcine coronary arteries

Alcohol consumption may be a risk factor for cerebrovascular stenosis in acute ischemic stroke and transient ischemic attack

BACKGROUND

Atherosclerosis are well established risk factors for ischemic stroke, however the association between alcohol consumption and atherosclerosis is controversial. This study aims to explore the potential correlation between alcohol consumption and cerebral stenosis in patients with acute ischemic stroke and transient ischemic attack (TIA).

METHODS

Nine hundreds and eighty-eight patients with first acute ischemic stroke attack or TIA were recruited retrospectively. Alcohol consumption was classified into five consumption categories (non-drinkers, occasional drinkers, < 140 g per week [mild drinkers], 140-279 g per week [moderate drinkers], ≥ 280 g per week [heavy drinkers]). Computed tomography angiography (CTA) and digital subtraction angiography (DSA) were utilized to assess the carotid and cerebral artery in all patients. Five-step scale for degree of stenosis was applied: normal (0, 0 points), mild (< 50%, 1 point), moderate (50-69%, 2 points), severe (70-99%, 3 points), and occlusion (100%, 4 points).

RESULTS

The carotid and cerebral artery stenosis scores were positively correlated with moderate alcohol consumption (B = 1.695, P < 0.001). Compared with nondrinkers, moderate alcohol consumption had significant increasing risk of moderate carotid and cerebral artery stenosis (OR = 4.28, 95% CI: 1.47-12.49, P = 0.008) and severe stenosis (OR = 4.24, 95% CI: 1.55-11.64, P = 0.005) and occlusion (OR = 3.87, 95% CI: 1.65-9.06, P = 0.002). Compared with nondrinkers, heavy alcohol consumption patients had significant higher risk of carotid and cerebral artery occlusion (OR = 2.71, 95% CI: 1.36-5.41, P = 0.005).

CONCLUSIONS

Higher alcohol consumption may associate with higher risk and more severity of carotid and cerebrovascular stenosis.

Plant Polyphenols and Their Potential Benefits on Cardiovascular Health: A Review

Fruits, vegetables, and other food items contain phytochemicals or secondary metabolites which may be considered non-essential nutrients but have medicinal importance. These dietary phytochemicals exhibit chemopreventive and therapeutic effects against numerous diseases. Polyphenols are secondary metabolites found in vegetables, fruits, and grains. These compounds exhibit several health benefits such as immune modulators, vasodilators, and antioxidants. This review focuses on recent studies on using dietary polyphenols to treat cardiovascular disorders, atherosclerosis, and vascular endothelium deficits. We focus on exploring the safety of highly effective polyphenols to ensure their maximum impact on cardiac abnormalities and discuss recent epidemiological evidence and intervention trials related to these properties. Kaempferol, quercetin, and resveratrol prevent oxidative stress by regulating proteins that induce oxidation in heart tissues. In addition, polyphenols modulate the tone of the endothelium of vessels by releasing nitric oxide (NO) and reducing low-density lipoprotein (LDL) oxidation to prevent atherosclerosis. In cardiomyocytes, polyphenols suppress the expression of inflammatory markers and inhibit the production of inflammation markers to exert an anti-inflammatory response. Consequently, heart diseases such as strokes, hypertension, heart failure, and ischemic heart disease could be prevented by dietary polyphenols.

Ginsenoside Rg3 attenuates myocardial ischemia/reperfusion injury via Akt/endothelial nitric oxide synthase signaling and the B‑cell lymphoma/B‑cell lymphoma‑associated X protein pathway

Previous studies have suggested that ginsenoside Rg3 (GSRg3) extract from the medicinal plant Panax ginseng, may increase nitric oxide production via increases in the phosphorylation and expression of endothelial nitric oxide synthase (eNOS). The present study used an in vitro neonatal rat cardiomyocyte (NRC) model of anoxia‑reoxygenation injury and an in vivo rat model of myocardial ischemia/reperfusion (MI/R) injury. Hemodynamic, histopathological and biochemical assessment of the myocardial injury was performed and the expression levels of lactate dehydrogenase (LDH), superoxide dismutase and creatine kinase (CK) were measured in serum from the animal model, which may reflect myocardial injury. NRC injury was determined using a Cell Counting kit‑8. The GSRg3 anti‑apoptotic effects were assessed using flow cytometry to investigate the number of early‑late apoptotic cells and western blot analysis was performed to analyze the protein expression levels of caspase‑3, caspase‑9, B‑cell lymphoma‑2 (Bcl‑2), phosphorylated (p‑)Akt and eNOS. The results suggested that pretreatment with GSRg3 (60 mg/kg) significantly improved rat cardiac function, as demonstrated by increased left ventricular systolic pressure, heart rate and first derivative of left ventricular pressure. GSRg3 also reduced the size of the myocardial infarct and LDH/CK levels in the blood following MI/R. In vitro investigations revealed that GSRg3 (10 mM) decreased NRC apoptosis through inhibiting the activation of caspase‑3 and caspase‑9, and increasing the expression levels of p‑Akt, eNOS and the ratio of Bcl‑2/Bcl‑2‑associated X protein (Bax). Overall, the present study revealed that GSRg3 mediated a cardioprotective effect against MI/R‑induced apoptosis via Akt/eNOS signaling and the Bcl‑2/Bax pathway.

Mechanistic studies of AVE3085 against homocysteine in endothelial protection

PURPOSE

Homocysteine (Hcy) is an independent risk factor for cardiovascular diseases that impairs endothelial function. We investigated whether the impaired endothelial function can be restored by the eNOS transcription enhancer AVE3085 in porcine coronary arteries. The effects of AVE3085 against Hcy on eNOS-NO function were studied and further investigations were conducted to reveal the role of arginase and the signaling pathway of eNOS activation in the effect of AVE3085 on endothelial dysfunction caused by Hcy.

METHODS

Myograph study of vasorelaxation, electrochemical measurement of NO, RT-PCR and Western blot analysis of eNOS, iNOS expression, and eNOS phosphorylation were performed. Arginase activity was determined by urea production and O2 (.-) generation by lucigenin-enhanced chemiluminenscence.

RESULTS

Exposure to Hcy for 24 h attenuated bradykinin-induced relaxation and NO release, downregulated eNOS mRNA expression and protein expressions of eNOS and p-eNOS(Ser1177) whereas it upregulated iNOS expression. AVE3085 restored NO release and relaxation, enhanced eNOS but decreased iNOS expression. Inhibition of protein kinase Akt or PI3 kinase attenuated the effect of AVE3085 on relaxation and eNOS phosphorylation. Arginase activity and O2 (.-) production were inhibited by AVE3085 in Hcy-exposed vessels.

CONCLUSIONS

AVE3085 prevents Hcy-induced endothelial dysfunction in coronary arteries by preservation of NO production and suppression of O2 (.-) generation. Preservation of NO is attributed to upregulation of eNOS expression, activation of eNOS via phosphorylation of Ser1177 through a PI3 kinase/Akt-dependent pathway, and inhibition of arginase. Reduction of O2 (.-) generation results from reversal of eNOS uncoupling and inhibition of arginase and iNOS.

Alcoholic fermentation induces melatonin synthesis in orange juice

Melatonin (N-acetyl-5-methoxytryptamine) is a molecule implicated in multiple biological functions. Its level decreases with age, and the intake of foods rich in melatonin has been considered an exogenous source of this important agent. Orange is a natural source of melatonin. Melatonin synthesis occurs during alcoholic fermentation of grapes, malt and pomegranate. The amino acid tryptophan is the precursor of all 5-methoxytryptamines. Indeed, melatonin appears in a shorter time in wines when tryptophan is added before fermentation. The aim of the study was to measure melatonin content during alcoholic fermentation of orange juice and to evaluate the role of the precursor tryptophan. Identification and quantification of melatonin during the alcoholic fermentation of orange juice was carried out by UHPLC-QqQ-MS/MS. Melatonin significantly increased throughout fermentation from day 0 (3.15 ng/mL) until day 15 (21.80 ng/mL) reaching larger amounts with respect to other foods. Melatonin isomer was also analysed, but its content remained stable ranging from 11.59 to 14.18 ng/mL. The enhancement of melatonin occurred mainly in the soluble fraction. Tryptophan levels significantly dropped from 13.80 mg/L (day 0) up to 3.19 mg/L (day 15) during fermentation. Melatonin was inversely and significantly correlated with tryptophan (r = 0.907). Therefore, the enhancement in melatonin could be due to both the occurrence of tryptophan and the new synthesis by yeast. In summary, the enhancement of melatonin in novel fermented orange beverage would improve the health benefits of orange juice by increasing this bioactive compound.

Phenolic fractions from Trifolium pallidum and Trifolium scabrum aerial parts in human plasma protect against changes induced by hyperhomocysteinemia in vitro

Elevated concentration of homocysteine (Hcy) in human plasma, defined as hyperhomocysteinemia has been correlated with some diseases, such as cardiovascular, neurodegenerative, and kidney disorders. Homocysteine occurs in human plasma in several forms, including the most reactive form of Hcy - its cyclic thioester - homocysteine thiolactone (HTL), which represents up to 0.29% of plasma total Hcy. It is suggested that Hcy and HTL may also act as oxidants, but various polyphenolic antioxidants are able to inhibit the oxidative damage induced by Hcy or HTL. The aim of our present study was to investigate in vitro oxidative changes in human plasma induced by the model of hyperhomocysteinemia in the presence of the phenolic fractions from selected clovers (Trifolium pallidum and Trifolium scabrum aerial parts). Hyperhomocysteinemia was stimulated by a reduced form of Hcy (final dose 100 μM) or HTL (final dose 1 μM). The aim of our study was also to explain the effect of the phenolic fractions on the coagulation activity of human plasma treated with Hcy and its thiolactone. Tested phenolic fractions significantly inhibited the oxidative stress (measured by the total antioxidant level - TAS) in plasma treated with Hcy or HTL. The phenolic fractions from T. pallidum and T. scabrum also caused a distinct reduction of plasma lipid peroxidation (measured by the level of thiobarbituric acid reactive substance) induced by the model of hyperhomocysteinemia. Moreover, tested fractions modulated the coagulation properties of plasma treated with homocysteine and its thiolactone. It seems that antioxidative activities of the phenolic fractions from T. pallidum and T. scabrum aerial parts may be responsible for their medicinal properties during hyperhomocysteinemia.

The polyphenol-rich extracts from black chokeberry and grape seeds impair changes in the platelet adhesion and aggregation induced by a model of hyperhomocysteinemia

OBJECTIVE

The mechanism action of the polyphenol-rich extracts from berries of Aronia melanocarpa (black chokeberry) and from grape seeds in the defence against homocysteine (Hcy) and its derivatives action in blood platelets is still unknown. In this study, the influence of the aronia extract and grape seeds extract (GSE) on the platelet adhesion to collagen and fibrinogen and the platelet aggregation during a model of hyperhomocysteinemia was investigated. The aim of our study in vitro was also to investigate superoxide anion radicals (O₂⁻•) production after incubation of platelets with Hcy, HTL and the aronia extract and GSE during a model of hyperhomocysteinemia (induced by reduced form of homocysteine at final dose of 100 μM) and the most reactive form of Hcy--its cyclic thioester, homocysteine thiolactone (HTL, 1 μM). Moreover, the additional aim of our study was also to establish and compare the influence of the aronia extract, GSE and resveratrol (3,4',5-trihydroxystilben), a phenolic compound, which has been supposed to be beneficial for the prevention of cardiovascular events, on selected steps of platelet activation.

METHODS

The effects of tested extracts on adhesion of blood platelets to collagen and fibrinogen were determined according to Tuszynski and Murphy. The platelet aggregation was determined by turbidimetry method using a Chrono-log Lumi-aggregometer.

RESULTS

We have observed that HTL, like its precursor-Hcy stimulated the generation of O₂⁻• (measured by the superoxide dismutase-inhibitable reduction of cytochrome c) in platelets and caused an augmentation of the platelet adhesion and aggregation induced by the strong physiological agonist-thrombin. Our present results in vitro also demonstrated that the aronia extract and grape seeds extract reduced the toxicity action of Hcy and HTL on blood platelet adhesion to collagen and fibrinogen, the platelet aggregation and superoxide anion radicals production in platelets, suggesting its potential protective effects on hemostasis during hyperhomocysteinemia.

CONCLUSION

In the comparative studies, the aronia extract was found to be more effective antiplatelet factors, than GSE or resveratrol during a model of hyperhomocysteinemia. It gives hopes for development of diet supplements, which may be important during hyperhomocysteinemia.

Wine, beer, alcohol and polyphenols on cardiovascular disease and cancer

Since ancient times, people have attributed a variety of health benefits to moderate consumption of fermented beverages such as wine and beer, often without any scientific basis. There is evidence that excessive or binge alcohol consumption is associated with increased morbidity and mortality, as well as with work related and traffic accidents. On the contrary, at the moment, several epidemiological studies have suggested that moderate consumption of alcohol reduces overall mortality, mainly from coronary diseases. However, there are discrepancies regarding the specific effects of different types of beverages (wine, beer and spirits) on the cardiovascular system and cancer, and also whether the possible protective effects of alcoholic beverages are due to their alcoholic content (ethanol) or to their non-alcoholic components (mainly polyphenols). Epidemiological and clinical studies have pointed out that regular and moderate wine consumption (one to two glasses a day) is associated with decreased incidence of cardiovascular disease (CVD), hypertension, diabetes, and certain types of cancer, including colon, basal cell, ovarian, and prostate carcinoma. Moderate beer consumption has also been associated with these effects, but to a lesser degree, probably because of beer's lower phenolic content. These health benefits have mainly been attributed to an increase in antioxidant capacity, changes in lipid profiles, and the anti-inflammatory effects produced by these alcoholic beverages. This review summarizes the main protective effects on the cardiovascular system and cancer resulting from moderate wine and beer intake due mainly to their common components, alcohol and polyphenols.

Aronia melanocarpa extract suppresses the biotoxicity of homocysteine and its metabolite on the hemostatic activity of fibrinogen and plasma

OBJECTIVE

Aronia melanocarpa fruits (Rosaceae) are one of the richest plant sources of phenolic substances, and it has been shown to have various biological activities. Berries of A. melanocarpa (chokeberry) have been supposed to be beneficial for the prevention of cardiovascular events. In this study the influence of aronia extract on the clot formation (using human plasma and purified fibrinogen) and the fibrin lysis during the model of hyperhomocysteinemia was investigated.

METHODS

Hyperhomocysteinemia was induced using a reduced form of Hcys (at final dose of 0.1mM) and the most reactive form of Hcys - its cyclic thioester, homocysteine thiolactone (HTL, 1 μM). The aim of our study in vitro was also to investigate the modifications of human plasma total proteins and the oxidative stress (by measuring the total antioxidant level - TAS) in plasma after incubation with Hcys, HTL and/or aronia extract. The biological properties of aronia extract were compared with the action of a well characterized antioxidative commercial polyphenol - resveratrol (3,4',5- trihydroxystilbene).

RESULTS

The HTL, like its precursor, Hcys stimulated polymerization of fibrinogen. The results also demonstrated that Hcys (0.1mM) and HLT at lower doses than Hcys (1 μM) reduced the fibrin lysis in human plasma. Moreover, Hcys and HTL change the level of thiol and amino groups in plasma total proteins and induce the oxidative stress in plasma. Our results indicate that aronia extract reduced the biotoxicity action of Hcys and HTL on hemostatic properties of fibrinogen or plasma, suggesting its possible protective properties in hyperhomocysteinemia - induced cardiovascular diseases. Moreover, our results showed that the extract from berries of A. melanocarpa due to antioxidant action, significantly reduced the oxidative stress (measured by TAS) in plasma during the model of hyperhomocysteinemia.

CONCLUSION

In the comparative studies, the extract from berries of A. melanocarpa and reseveratrol had similar protective properties. It gives hopes for development of diet supplements, which may be preventing thrombosis in pathological states where plasma procoagulant activity and oxidative stress are observed e.g. in hyperhomocysteinemia.

Ginsenoside Rb1 preconditioning enhances eNOS expression and attenuates myocardial ischemia/reperfusion injury in diabetic rats

Diabetes mellitus is associated with decreased NO bioavailability in the myocardium. Ginsenoside Rb1 has been shown to confer cardioprotection against ischemia reperfusion injury. The aim of this study was to investigate whether Ginsenoside Rb1 exerts cardioprotective effects during myocardial ischemia-reperfusion in diabetic rats and whether this effect is related to increase the production of NO via enhancing eNOS expression in the myocardium. The myocardial I/R injury were induced by occluding the left anterior descending artery for 30 min followed by 120 min reperfusion. An eNOS inhibitor L-NAME or Rb1 were respectively administered 25 min or 10 min before inducing ischemia. Ginsenoside Rb1 preconditioning reduced myocardial infarct size when compared with I/R group. Ginsenoside Rb1 induced myocardial protection was accompanied with increased eNOS expression and NO concentration and reduced plasma CK and LDH (P < 0.05). Moreover, the myocardial oxidative stress and tissue histological damage was attenuated by Ginsenoside Rb1 (P < 0.05). L-NAME abolished the protective effects of Ginsenoside Rb1. It is concluded that Ginsenoside Rb1 protects against myocardium ischemia/reperfusion injury in diabetic rat by enhancing the expression of eNOS and increasing the content of NO as well as inhibiting oxidative stress.

Response of blood platelets to resveratrol during a model of hyperhomocysteinemia

Resveratrol (3,4',5-trihydroxystilben), a phenolic antioxidant synthesized in grapes and other plants, and also present in wine, has been suggested to help prevent cardiovascular events. In this study the influence of resveratrol on platelet aggregation during a model of hyperhomocysteinemia was investigated. We induced hyperhomocysteinemia using a reduced form of Hcys (final dose, 0.1 mM) and the most reactive form of Hcys, its cyclic thioester, homocysteine thiolactone (HTL, 1 µM). The aim of our study in vitro was also to investigate superoxide anion radical (O(2)(-)) generation after incubation of platelets with Hcys, HTL, and resveratrol. We have observed that HTL, like its precursor Hcys, stimulated the generation of (O(2)(-) in platelets and caused an augmentation of platelet aggregation induced by the strong physiological agonist thrombin. Our results in vitro also demonstrated that resveratrol reduced the toxic action of Hcys and HTL on blood platelet aggregation and superoxide anion radical production in platelets, suggesting its potential protective effects on hemostasis are negatively influenced by homocysteine and its derivatives.

Effect of resveratrol on hemostatic properties of human fibrinogen and plasma during model of hyperhomocysteinemia

Resveratrol (3,4', 5 - trihydroxystilben), a phenolic antioxidant synthesized in grapes and vegetables and presents in wine, has been supposed to be beneficial for the prevention of cardiovascular events. In this study the influence of resveratrol on the clot formation (using human plasma and purified fibrinogen) and the fibrin lysis during model of hyperhomocysteinemia was investigated. We induced this process using a reduced form of Hcys (at final dose of 0.1mM) and the most reactive form of Hcys - its cyclic thioester, homocysteine thiolactone (HTL, 0.5μM). The aim of our study in vitro was to investigate the modifications of human plasma total proteins after incubation with Hcys, HTL and resveratrol. We observed that HTL, like its precursor, Hcys stimulated polymerization of fibrinogen. Our present results also demonstrated that Hcys (0.1mM) and HLT at lower doses than Hcys (0.5μM) reduced the fibrin lysis in human plasma. Moreover, Hcys and HTL change the level of thiol and amino groups in plasma total proteins. Our results indicate that resveratrol reduced the toxicity action of Hcys and HTL on hemostatic properties of fibrinogen or plasma, suggesting its possible protector role in hyperhomocysteinemia - induced cardiovascular diseases.

Endothelial nitric oxide synthase gene variants and primary open-angle glaucoma: interactions with hypertension, alcohol intake, and cigarette smoking

OBJECTIVE

To evaluate whether an association between risk of any of the factors of hypertension, alcohol intake, and cigarette smoking and the risk of primary open-angle glaucoma (POAG) depended on nitric oxide synthase 3 (NOS3) gene variants.

METHODS

Two functional single-nucleotide polymorphisms (SNPs) (T-786C [rs2070744] and Glu298Asp [rs1799983]) and 2 tagging SNPs (rs7830 and rs3918188) were evaluated in nested case-control studies from the Nurses' Health Study (1980-2002) and the Health Professionals' Follow-up Study (1986-2002). Participants were 40 years of age or older and white, and were followed up biennially. We included 527 incident case patients with POAG and 1539 control participants, matched by cohort, age, and eye examination at the matched case patients' diagnosis dates. Cohort-specific relative risks were estimated using multivariable conditional logistic regression and were pooled using meta-analytic methods.

RESULTS

The association between hypertension and POAG depended on T-786C SNP variants. Compared with TT homozygotes without hypertension, the TT homozygotes with hypertension were at significantly higher risk of POAG (relative risk,1.45 [95% confidence interval, 1.01-2.08]); however, among carriers of the variant (C) allele, hypertension was not associated with POAG (P interaction = .007). Similarly, compared with CC homozygotes with the rs7830 tagging SNP who never smoked, CC homozygotes who were past or current smokers were at significantly higher risk of POAG (relative risk, 1.63 [95% confidence interval, 1.15-2.31]); however, among carriers of the variant allele (A), smoking was not associated with POAG (P interaction = .004). Interactions were not observed with alcohol intake.

CONCLUSIONS

The associations between hypertension and cigarette smoking in relation to POAG depended on NOS3 SNPs.

Effects of red grape juice consumption on high density lipoprotein-cholesterol, apolipoprotein AI, apolipoprotein B and homocysteine in healthy human volunteers

It has suggested that grape juice consumption has lipid- lowering effect and it is associated with a decreased risk of heart disease. We aimed to evaluate the effects of red grape juice (RGj) consumption on high density lipoprotein-cholesterol (HDL-C), apolipoprotein AI (apoAI), apolipoprotein B (apoB) and homocysteine (Hcy) levels in healthy human volunteers. Twenty six healthy and nonsmoking males, aged between 25-60 years, who were under no medication asked to consume 150 ml of RGj twice per day for one month. Serum HDL-C, apoAI, apoB and plasma Hcy levels were measured before and after one month RGj consumption. HDL-C levels after RGj consumption were significantly higher than the corresponding levels before the RGj consumption (41.44 ± 4.50 and 44.37 ± 4.30 mg/dl; P<0.0001). Also, apoB was significantly increased after RGj consumption (149.0 ± 22.35 and 157.19 ± 18.60 mg/dl; P<0.002). But apoAI levels were not changed significantly before and after of RGj consumption (154.27 ± 21.55 and 155.35 ± 21.07 mg/dl; P>0.05). Hcy levels were decreased after RGj consumption (7.70 ± 2.80 and 6.20 ± 2.30 µmol/l; P<0.001). The present study demonstrates that RGj consumption can significantly increase serum HDL-C levels and decrease Hcy levels. These findings may have important implications for the prevention of atherosclerosis in healthy individuals.

Ginsenoside Rb1 preconditioning protects against myocardial infarction after regional ischemia and reperfusion by activation of phosphatidylinositol-3-kinase signal transduction

BACKGROUND

Ginsenoside Rb1, a major bioactive component of Panax ginseng, bears various beneficial effects on the cardiovascular system. This study investigated whether ginsenoside Rb1 preconditioning has protective effects on myocardial ischemia-reperfusion injury and its potential mechanism.

METHODS

Rats subjected to 45 min of myocardial ischemia followed by 120 min of reperfusion were assigned to the following groups: sham-operated, ischemia-reperfusion (I/R), ginsenoside Rb1+I/R, wortmannin(a specific PI3K inhibitor)+I/R, wortmannin drug vehicle (dimethyl sulfoxide, DMSO), wortmannin+sham, ginsenoside Rb1+ wortmannin +I/R. Infarct size was assessed by triphenyltetrazolium chloride staining. Plasma creatine kinase (CK), creatine kinase isoenzyme MB (CK-MB), lactate dehydrogenase (LDH), and troponin T levels were also measured. Akt phosphorylation expression was assessed by immunoblotting.

RESULTS

Ginsenoside Rb1 preconditioning reduced infarct size compared with that in the I/R group: 30 +/- 2.6% versus 51 +/- 2.7% (p < 0.01). Ginsenoside Rb1 preconditioning also markedly reduced the plasma CK, CK-MB, LDH and troponin T levels in blood. Akt phosphorylation expression increased after ginsenoside Rb1 preconditioning. These effects of ginsenoside Rb1 preconditioning were significantly inhibited by wortmannin.

CONCLUSION

This is the first study to demonstrate that ginsenoside Rb1 preconditioning has protective effects on myocardial ischemia and reperfusion injury, partly by mediating the activation of the PI3K pathway and phosphorylation of Akt.

Ginkgolide A attenuates homocysteine-induced endothelial dysfunction in porcine coronary arteries

BACKGROUND

Homocysteine is an independent risk factor for atherosclerosis. The objective of this study was to investigate whether ginkgolide A (GA), a major constituent of Ginkgo biloba, could block homocysteine-induced endothelial dysfunction in porcine coronary arteries.

METHODS

Porcine coronary artery rings were assigned to six treatment groups: control; homocysteine (50 micromol/L); low-dose (50 micromol/L) or high-dose (100 micromol/L) GA; and homocysteine plus low-dose or high-dose GA. After 24 hours' incubation, the rings were analyzed for vasomotor function in response to a thromboxane A2 analogue (U46619), bradykinin, and sodium nitroprusside. Endothelial nitric oxide synthase (eNOS) was studied by using real-time polymerase chain reaction and immunohistochemistry analysis. Superoxide anion production was assessed by chemoluminescence analysis.

RESULTS

Endothelium-dependent relaxation (bradykinin) was significantly reduced in ring segments treated with homocysteine as compared with the control (P < .05). When homocysteine was combined with either low-dose or high-dose GA, endothelium-dependent relaxation was markedly recovered. There was no significant difference in maximal contraction (U46619) or endothelium-independent relaxation (sodium nitroprusside) among all groups. In addition, superoxide anion production was increased by 113% in the homocysteine-treated group, whereas there was no statistically significant difference between the control and GA/homocysteine groups. Furthermore, eNOS messenger RNA and protein levels were substantially reduced in the homocysteine-treated group (P < .05), but not in the GA/homocysteine combined groups.

CONCLUSIONS

Homocysteine significantly impairs endothelium-dependent vasorelaxation through oxidative stress and downregulation of eNOS in porcine coronary arteries. GA effectively prevents homocysteine-induced endothelial dysfunction and molecular changes in porcine coronary arteries. This study underscores the potential clinical benefits and applications of GA in controlling homocysteine-associated vascular injury and cardiovascular disease.

CLINICAL RELEVANCE

Homocysteine is an independent risk factor for atherosclerosis. This study showed that ginkgolide A, a major constituent of Ginkgo biloba, effectively prevents homocysteine-induced endothelial dysfunction and molecular changes in porcine coronary arteries. This study underscores potential clinical benefits and applications of ginkgolide A in controlling homocysteine-associated vascular injury and cardiovascular disease.

Ginseng Saponins Diminish Adverse Vascular Effects Associated with Chronic Methionine-Induced Hyperhomocysteinemia

Recent studies have shown that Panax ginseng has a variety of beneficial effects on the cardiovascular systems. Homocysteine (Hcy), which is derived from L-methionine (Met), has been closely associated with the increased risk of cardiovascular diseases. In the present study, we examined whether in vivo long-term administration of ginseng saponins (GS), active ingredients of Panax ginseng, attenuate adverse vascular effects associated with chronic Met-induced hyperhomocysteinemia (H-Hcy). We found that plasma Hcy level, which was measured after 30 and 60 d, in GS (100 mg/kg)+Met co-administration group was significantly reduced when it was compared with Met alone treatment group. We could also observe the alleviation of endothelial damages of aortic artery vessels in GS (100 mg/kg)+Met co-administration group compared with Met alone treatment group. We compared aortic vasocontractile and vasodilatory responses between Met alone and GS (100 mg/kg)+Met co-treatment groups. We found that norepinephrine-induced vasocontractile responses were greatly decreased in GS (100 mg/kg)+Met co-treatment group and that carbachol-induced dilatory responses were greatly enhanced in GS (100 mg/kg)+Met co-administration groups as compared with Met alone treatment group. The present results indicate that in vivo long-term administration of GS attenuates adverse vascular effects associated with chronic Met-induced H-Hcy in rats.

Direct vasoactive and vasoprotective properties of anthocyanin-rich extracts

Reactive oxygen species (ROS) play a critical role in the impairment of nitric oxide-mediated vascular functions and overall pathogenesis associated with cardiovascular disease. Plant pigment anthocyanins are exceptionally potent oxygen radical scavengers that produce beneficial effects in diseases outside the cardiovascular system. We examined for the first time the potential coronary vasoactive and vasoprotective properties of three anthocyanin enhanced extracts prepared from chokeberry (Ck), bilberry (B), or elderberry (E). Coronary arterial rings were isolated from 64 pigs and incubated in sterile tissue culture media overnight for use in one of four separate in vitro isometric force recording studies. Ck and B, but not E, produced dose- and endothelium-dependent vasorelaxation. (%maximal relaxation at 5 mg total anthocyanins per liter: Ck = 68 +/- 11, B = 59 +/- 10). Coronary vascular tone, endothelium-dependent vasorelaxation to A23187, and vasorelaxation to DEA NONOate were not affected by exposure of rings to any extract at 0.05 mg total anthocyanins per liter for 5 or 30 min. Ck extract at 0.05 mg total anthocyanins per liter showed the greatest protection against loss of A23187 relaxation following exposure to ROS from pyrogallol (Ck, % maximal relaxation and -logED50 to A23187, respectively, means +/- SE: Ck alone, 93 +/- 5%, 7.91 +/- 0.1; pyrogallol alone, 76 +/- 7%, 7.46 +/- 0.06; pyrogallol + Ck, 98 +/- 1%, 7.82 +/- 0.06; control: 99 +/- 1%, 7.86 +/- 0.07; P < 0.05 control vs. pyrogallol alone). Neither the extracts nor pyrogallol affected responses to DEA NONOate. Thus anthocyanin-enhanced extracts produce endothelium-dependent relaxation in porcine coronary arteries. Extract concentrations too low to directly alter coronary vascular tone protect coronary arteries from ROS without altering vasorelaxation to endogenous or exogenous NO. These results suggest that such extracts could have significant beneficial effects in vascular disease.

Effects of 5 HIV protease inhibitors on vasomotor function and superoxide anion production in porcine coronary arteries

HIV protease inhibitors (PIs) have been implicated to cause cardiovascular complications. Previous studies demonstrated that the PI ritonavir (RTV) caused endothelial dysfunction in porcine arteries. This study investigated and compared the effects of 5 commonly used PIs on vasomotor function, endothelial nitric oxide synthase (eNOS) expression, and oxidative stress in porcine coronary arteries. Vessel rings were incubated with 15 microM of RTV, amprenavir (APV), saquinavir (SQV), indinavir (IDV), or nelfinavir (NFV) for 24 hours. Vasomotor function was studied using a myograph system. The contractility of the rings was significantly reduced for RTV and SQV. In response to bradykinin at 10(-5) M, the endothelium-dependent relaxation was significantly reduced for RTV, APV, and SQV. The eNOS mRNA levels were significantly reduced for RTV, APV, and SQV. Furthermore, the superoxide anion (O(2)(-)) levels of the vessels were significantly increased for RTV and APV. It was found that nitric oxide production was decreased, whereas the level of nitrotyrosine proteins was increased in RTV-treated vessels. Furthermore, antioxidant seleno-L-methionine (SeMet) reversed RTV-induced O(2)(-) production and vasomotor dysfunction. Thus, the HIV PIs RTV, APV, and SQV at 15 microM have more potent in vitro effects on vasomotor dysfunction, eNOS downregulation, and O(2)(-) production than IDV and NFV. The antioxidant SeMet can block these adverse effects of RTV. The results suggest that antioxidant therapy may have applications for controlling PI-associated cardiovascular complications.

Wild blueberry-rich diets affect the contractile machinery of the vascular smooth muscle in the Sprague-Dawley rat

Weanling male Sprague-Dawley rats were randomly fed a control diet (AIN-93) (C) or a blueberry diet (B) for 13 weeks, or a reverse diet (R) (C diet for 13 weeks, switched to the B diet for 8 weeks). Aortas were excised, and two intact and two endothelium-denuded rings were immersed in tissue baths containing physiological salt solution at 37 degrees C and aerated with 95% O(2) and 5% CO(2) (pH 7.4). Following equilibration and preconditioning under 1.5-g preload, cumulative dose-response curves were generated with six doses of the alpha1-adrenergic receptor-selective agonist L-phenylephrine (L-Phe, 10(8)-3 x 10(-6) M) and relaxed with one dose of acetylcholine (3 x 10(-6) M) to assess intact endothelium. The maximum force of contraction (Fmax) and vessel sensitivity (pD(2)) were determined in intact and endothelium-denuded rings. A two-way analysis of variance test revealed that blueberry-fed animals (B and R diets) developed a significantly lower F (max) (0.873 +/- 0.0463 and 0.9266 +/- 0.0463 g, respectively) when contracted with L-Phe, compared with the animals on the C diet (1.109 +/- 0.0463 g) (P < .05). The pD(2) of the intact rings was not significantly different among diet groups. Additionally, diet did not significantly affect the mean F (max) or pD(2) of endothelium-denuded rings. Our results indicate for the first time that wild blueberries incorporated into the diet affect the vascular smooth muscle contractile machinery by suppressing the alpha1-adrenergic receptor agonist-mediated contraction while having no effect on membrane sensitivity of the endothelial or vascular smooth muscle cell layer. Furthermore, their mechanism of action seems to be accomplished through an endothelium-dependent pathway.

Curcumin Blocks HIV Protease Inhibitor Ritonavir-Induced Vascular Dysfunction in Porcine Coronary Arteries

BACKGROUND

HIV protease inhibitor ritonavir (RTV) is associated with many cardiovascular complications and causes vascular dysfunction through oxidative stress. In the present study, we determined the effects of RTV and curcumin (a pigment derived from turmeric) on porcine coronary arteries.

STUDY DESIGN

Artery rings were incubated with 15 microM concentration of RTV and curcumin (5 or 10 microM) for 24 hours. Vasomotor function was studied with a myograph tension system. Endothelial nitric oxide synthase (eNOS) mRNA and protein levels were studied using real-time polymerase chain reaction, Western blot, and immunohistochemistry. Nitric oxide was measured using Griess assay. Superoxide anion levels were determined by lucigenin enhanced chemiluminescence.

RESULTS

RTV considerably reduced vessel contraction by 71%, endothelium-dependent relaxation by 59%, and endothelium-independent relaxation by 52%, as compared with controls. Curcumin effectively blocked RTV-induced vasomotor dysfunction. RTV-treated arteries showed substantial reductions of eNOS mRNA by 77%, eNOS protein by 72%, and nitric oxide release by 37% as compared with controls. The RTV plus curcumin-treated vessels showed substantial increases of eNOS and nitric oxide levels as compared with the RTV-treated vessels. Finally, there was a 47% increase of superoxide anion production in the RTV-treated vessels as compared with controls. Again, curcumin effectively reversed this effect of RTV.

CONCLUSIONS

HIV protease inhibitor RTV impairs vasomotor functions, reduces eNOS expression and nitric oxide release, and increases oxidative stress in porcine coronary arteries. Curcumin effectively blocks these detrimental effects of RTV.

Ginsenoside Rb1 blocks homocysteine-induced endothelial dysfunction in porcine coronary arteries

OBJECTIVE

Homocysteine (Hcy) is an independent risk factor for atherosclerosis. This study investigates the effects of ginsenoside Rb1, a major constituent of ginseng, on Hcy-induced endothelial dysfunction and molecular changes in porcine coronary arteries.

METHODS

The coronary arteries were harvested from pig hearts and cut into 5-mm ring segments, which were then divided into six groups, including control, Hcy alone (50 microM), low-dose (1 microM) or high-dose (10 microM) Rb1 alone, and Hcy plus low-dose or high-dose Rb1. After 24-hour incubation, the rings were analyzed for vasomotor function in response to thromboxane A2 analog U46619, bradykinin, and sodium nitroprusside (SNP), respectively. In addition, superoxide anion was assessed by lucigenin-enhanced chemiluminescence analysis. Endothelial nitric oxide synthase (eNOS) was studied using real-time polymerase chain reaction and Western blot.

RESULTS

Endothelium-dependent relaxation (bradykinin) was significantly reduced in rings treated with Hcy alone as compared with the control (49.80% vs 71.77%, n = 8, P < .05), whereas neither high-dose nor low-dose Rb1 alone affected the endothelium-dependent relaxation. The low-dose Rb1-Hcy combined group had a partially improved endothelium-dependent relaxation (54.44%), whereas the high-dose Rb1-Hcy combined group showed a complete recovery of endothelium-dependent relaxation (72.89%). There was no substantial difference in maximal contraction induced by U46619 or endothelium-independent relaxation by SNP among all groups (P > .05). Furthermore, superoxide anion was markedly increased by 137% in the Hcy-treated group as compared with the control, but there were no statistically significant changes from the control in all other groups (P > .05). Lastly, eNOS mRNA and protein levels were substantially reduced in the Hcy-treated group, but not in the Rb1-Hcy combined groups.

CONCLUSIONS

This is the first study to show that ginsenoside Rb1 can effectively block Hcy-induced endothelial dysfunction and superoxide anion production as well as eNOS downregulation in porcine coronary arteries. This study suggests that ginseng and its active constituents may have potential clinical applications in controlling Hcy-associated vascular injuries.

CLINICAL RELEVANCE

Homocysteine (Hcy) is an independent risk factor for atherosclerosis and other vascular lesions. It causes endothelial dysfunction and oxidative stress. Ginseng compounds have effects of vasorelaxation and antioxidation. The purpose of this study was to determine the effect of ginsenoside Rb1, a major constituent of ginseng, on Hcy-induced endothelial dysfunction and molecular changes in porcine coronary arteries. Our results showed that ginsenoside Rb1 can effectively block Hcy-induced dysfunction of endothelium-dependent vasorelaxation as well as superoxide anion production and eNOS downregulation. This study suggests that ginseng compounds may have potential clinical applications in controlling Hcy-associated vascular diseases and other vascular lesions.

Effects of progesterone and estrogen on endothelial dysfunction in porcine coronary arteries

BACKGROUND

The effects of hormone replacement therapy (HRT) on the vascular endothelium have been controversial. In this study, we determined the effects of HRT on endothelium-dependent relaxation in a porcine coronary artery model.

METHODS

Coronary artery rings harvested from female swine were incubated as controls or with estrogen (10(-9), 10(-8), 10(-7) g/L), progesterone (1 x 10(-6), 1 x 10(-5), 5 x 10(-5) g/L), or a combination of the two (10(-8)g/L estrogen, 1 x 10(-5)g/L progesterone). After 24 h in tissue culture, the rings were tested on a myograph system to measure contraction and endothelium-dependent relaxation. Myograph analysis was performed with the thromboxane A2 analogue U46619 for contraction and bradykinin or sodium nitroprusside for relaxation. Nitric oxide synthase (eNOS) levels were determined by immunohistochemistry. Levels of superoxide anion in the progesterone or estrogen treated tissues were assessed by lucigenin-enhanced chemiluminescence analysis.

RESULTS

In response to 10(-7)M bradykinin, porcine coronary artery rings treated with 1 x 10(-6), 1 x 10(-5) and 5 x 10(-5) g/L of progesterone showed a significant reduction in endothelium-dependent vasorelaxation by 36%, 45%, and 68%, respectively, as compared to controls (P <0.05). However, rings treated with estrogen showed no significant difference as compared to controls. Furthermore, estrogen treatment with progesterone reversed the effect of progesterone, showing no difference in vessel relaxation as compared to controls. There were no differences in endothelium-independent vasorelaxation (sodium nitroprusside) or in smooth muscle contractility (U46619) between the control and the hormone-treated groups. The eNOS immunoreactivity was reduced in progesterone-treated coronary artery rings. Furthermore, coronary endothelium exposed to progesterone showed a 59% increase in superoxide anion production, while estrogen produced a 67% decrease when compared to controls (P <0.05 for both).

CONCLUSION

This data suggests that the progesterone component of HRT has a detrimental influence on endothelium-dependent relaxation. This effect appears to be related to decreased eNOS levels, as well as increased consumption of NO by superoxide anion in the endothelium of tissues exposed to progesterone. Estrogen can block progesterone-induced endothelial dysfunction and superoxide anion production in the pig coronary artery model.

Adipocyte-derived cytokine resistin causes endothelial dysfunction of porcine coronary arteries

OBJECTIVE

Resistin, a novel adipocyte-derived cytokine, is involved in the development of insulin resistance and diabetes mellitus. In this study, we determined whether resistin could affect vasomotor function, oxidative stress, and endothelial nitric oxide synthase (eNOS) expression in porcine coronary arteries.

METHODS

Porcine coronary arteries were treated with resistin or antioxidant seleno-L-methionine (SeMet). Vasomotor function was studied by using a myograph system. Levels of superoxide anion (O 2 - ) were detected by the lucigenin-enhanced chemiluminescence method. The eNOS mRNA and protein levels were determined by real-time polymerase chain reaction and immunohistochemistry, respectively. Culture of isolated porcine coronary artery endothelial cells (PCAECs) was also included.

RESULTS

Endothelium-dependent relaxation in response to bradykinin was reduced by 15% and 30% for the rings treated with 10 and 40 ng/mL of resistin, respectively, as compared with controls ( P < .05). Endothelium-independent relaxation in response to sodium nitroprusside (SNP) was also reduced by 11% after treatment with 40 ng/mL of resistin ( P < .05). The O 2 - level was increased in the 40 ng/mL resistin-treated vessels by 88% as compared with controls ( P < .05). SeMet reversed these effects. The eNOS mRNA levels in PCAEC cultures treated with resistin (10 and 40 ng/mL) were decreased by 27% and 55%, respectively ( P < .05) and by 39% in the endothelial cells purified from porcine coronary artery rings after treatment with 40 ng/mL of resistin ( P < .05). Immunoreactivity of eNOS in the resistin-treated vessel rings was also substantially reduced.

CONCLUSIONS

Resistin reduces the endothelium-dependent and endothelium-independent vasorelaxation. This effect is associated with increased superoxide radical production, decreased eNOS expression, and is effectively reversed by the antioxidant SeMet.

CLINICAL RELEVANCE

Obesity has been considered to be an independent risk factor for coronary artery disease and other vascular lesions. Resistin is a newly discovered adipocyte-derived cytokine, and its plasma levels are increased in obese individuals. However, it is not clear whether resistin could directly contribute to vascular disease formation. This study showed that resistin can cause endothelial dysfunction in porcine coronary arteries through oxidative stress and down-regulation of eNOS. Thus, this study may suggest a new mechanism of obesity-associated vascular disease and that antioxidants may effectively prevent vascular disease in obese individuals.

Curcumin blocks homocysteine-induced endothelial dysfunction in porcine coronary arteries

PURPOSE

Curcumin, a yellow polyphenolic compound from the plant Curcuma ionga , is a commonly used spice and coloring agent with beneficial effects of anti-tumor, anti-inflammatory, and antioxidant activities. The objective of this study was to determine the effect of curcumin on homocysteine-induced endothelial dysfunction in a porcine coronary artery model.

METHODS

Porcine coronary arteries were cut into 5-mm rings, which were incubated for 24 hours either as control rings, with homocysteine (50 micromol/L), curcumin (5 micromol/L), or a combination of curcumin (5 micromol/L) and homocysteine (50 micromol/L). Myograph tension analysis was performed in response to vessel active drugs including thromboxane A2 analog U466419 (contraction), endothelium-dependent vasorelaxation (bradykinin), and endothelium-independent vasorelaxation (sodium nitroprusside). Immunohistochemical staining was performed for endothelial nitric oxide synthase (eNOS). In addition, superoxide anion production was determined by lucigenin-enhanced chemiluminescence.

RESULTS

All groups of porcine coronary artery rings showed no difference in maximal contraction after U46619 challenge. However, endothelium-dependent vasorelaxation in response to 10(-5) mol/L bradykinin was 40% in the homocysteine-treated group, as compared to 73% in the control group (P = .03). Of importance, curcumin could effectively block homocysteine-induced impairment of endothelium-dependent vasorelaxation. All groups showed no difference in endothelium-independent vasorelaxation. In addition, eNOS immunoreactivity was reduced in the homocysteine group, but the combined homocysteine and curcumin group showed eNOS levels comparable to those in the control group. Furthermore, superoxide anion levels of the endothelial layer were significantly increased by 2-fold in homocysteine-treated vessels as compared to control vessels (P = .02), whereas curcumin could block the effect of homocysteine on superoxide anion production.

CONCLUSION

These data demonstrate that curcumin effectively reverses the endothelial dysfunction induced by homocysteine. In addition, curcumin significantly blocked homocysteine-induced superoxide anion production and eNOS down-regulation. This study suggests a therapeutic role for dietary curcumin in patients with homocysteinemia, thereby reducing cardiovascular morbidity and mortality.

CLINICAL RELEVANCE

Hyperhomocysteinemia is a significant clinical problem. It is an independent risk factor for cardiovascular diseases. This study provides new information for better understanding the molecular mechanisms of homocysteine-induced vascular injury. More importantly, curcumin, a natural substance, can effectively block the detrimental effect of homocysteine on the vascular system. Thus curcumin could be used in patients with hyperhomocysteinemia, and to prevent cardiovascular diseases.

Ginsenosides block HIV protease inhibitor ritonavir-induced vascular dysfunction of porcine coronary arteries

Human immunodeficiency virus (HIV) protease inhibitor ritonavir (RTV) may induce vascular dysfunction through oxidative stress. Ginsenosides have been shown to have potential benefits on the cardiovascular system through diverse mechanisms, including antioxidative property. The objective of this study was to determine whether ginsenosides could prevent coronary arteries from RTV-induced dysfunction. Porcine coronary artery rings were incubated with RTV and ginsenosides Rb1, Rc, and Re for 24 h. Vasomotor function was recorded by a myograph tension system. In response to the thromboxane A(2) analog U-46619, the contraction of the vessel rings was significantly reduced. When cocultured with Rb1, Rc, and Re, the contractility significantly increased. In response to bradykinin at 10(-5) M, the endothelium-dependent relaxation of vessel rings was significantly reduced by 59% for RTV compared with controls (P < 0.05). When cocultured with Rb1, Rc, and Re, the relaxation significantly increased 100%, 90%, and 134%, respectively, compared with the RTV-alone groups (P > 0.05). In response to sodium nitroprusside, RTV significantly reduced vasorelaxation. In addition, the endothelial nitric oxide synthase (eNOS) mRNA levels were significantly reduced by 78% for RTV group (P < 0.05) by real-time PCR analysis. The eNOS protein levels measured by Western blot analysis and nitrite concentrations measured by Griess assay were also decreased, whereas O(2)(-) production by lucigenin-enhanced chemiluminescence was significantly increased in the RTV-treated group. These effects of RTV were effectively blocked by ginsenosides. Thus HIV protease inhibitor RTV significantly impaired the vasomotor function of porcine coronary arteries. This effect may be mediated by the downregulation of eNOS and overproduction of O(2)(-). These results suggest that ginsenosides can effectively block RTV-induced vascular dysfunction.