Effects of Moderate Alcohol Consumption on Platelet Function, Tissue-Type Plasminogen Activator and Plasminogen Activator Inhibitor

Predisposing factors to post-operative adhesion development

BACKGROUND

Adhesion development is the most common sequelae of intra-abdominal and pelvic surgery and represents a significant, yet poorly understood, cause of morbidity among post-operative patients. It remains unclear, for example, exactly why adhesions form more frequently in certain tissues and/or patients, or at specific locations within them, as opposed to others. This review contributes to the growing knowledge pool by elucidating factors that potentially predispose to the development of adhesions. Given the strong correlation between a hypofibrinolytic state and adhesion formation, this review article will examine not only those factors that have been shown to directly predispose to adhesion development, but also those that are likely do so indirectly by means of altering the coagulation/fibrinolytic profile.

METHODS

A literature search was performed using the PubMed database for all relevant English language articles up to February 2014. All of the identified articles were reviewed with particular attention to predisposing factors to post-operative adhesion development. In addition, the reference lists of each article were reviewed to identify additional relevant articles.

RESULTS

Various factors have been shown to directly increase the risk of post-operative adhesion development; namely, certain genetic polymorphisms in the interleukin-1 receptor antagonist, increased estrogen exposure, and endometriosis. In addition, numerous factors are known to increase the risk of fibrosis, therefore likely increasing the risk of adhesion development indirectly. These factors include genetic polymorphisms in plasminogen activator inhibitor-1 and thrombin-activatable fibrinolysis inhibitor, diabetes mellitus, metabolic syndrome, hyperglycemia, obesity, depression, binge alcohol consumption, anti-Parkinsonian medications, oral hormone therapy, pregnancy, and cancer.

CONCLUSIONS

The literature reviewed in this paper will help to direct future research aimed at understanding the mechanisms that underlie the association of certain factors with adhesion development. This information will be crucial in the creation of adequate preventative and treatment strategies.

Does white wine qualify for French paradox? Comparison of the cardioprotective effects of red and white wines and their constituents: resveratrol, tyrosol, and hydroxytyrosol

It is generally believed that the French paradox is related to the consumption of red wine and not other varieties of wine, including white wine or champagne. Some recent studies have indicated that white wine could also be as cardioprotective as red wine. The present investigation compares the cardioprotective abilities of red wine, white wine, and their principal cardioprotective constituents. Different groups of rats were gavaged with red wine, white wine, resveratrol, tyrosol, and hydroxytyrosol. Red wine and its constituent resveratrol and white wine and its constituents tyrosol and hydroxytyrosol all showed different degrees of cardioprotection as evidenced by their abilities to improve postischemic ventricular performance, reduce myocardial infarct size and cardiomyocyte apoptosis, and reduce peroxide formation. It was discovered in this study that although each of the wines and their components increased the enzymatic activities of the mitochondrial complex (I-IV) and citrate synthase, which play very important roles in oxidative phosphorylation and ATP synthesis, some of the groups were more complex-specific in inducing the activity compared to the other groups. Cardioprotective ability was further confirmed by increased expression of phospho-Akt, Bcl-2, eNOS, iNOS, COX-1, COX-2, Trx-1, Trx-2, and HO-1. The results of this study suggest that white wine can provide cardioprotection similar to red wine if it is rich in tyrosol and hydroxytyrosol.

Polyphenolic grape extract inhibits platelet activation through PECAM-1: an explanation for the French paradox

BACKGROUND

Moderate and prolonged consumption of red wine is associated with decreased cardiovascular morbidity and mortality. Inhibition of platelet functions by ingredients in red wine is thought to be one of the causes. However, the molecular mechanism of this inhibition has remained unexplained.

MATERIALS AND METHODS

We measured aggregation, changes in cytosolic Ca(2+) and tyrosine phosphorylation of the inhibitory receptor platelet endothelial cell adhesion molecule-1 (PECAM-1) in platelets stimulated with thrombin receptor (PAR-1) activating peptide (TRAP) and ADP and investigated the effects of alcohol-free polyphenolic grape extract (PGE), alcohol, and the polyphenols catechin, epi-catechin, resveratrol, trans-resveratrol, and gallic acid.

RESULTS

Polyphenolic grape extract induced dose-dependent inhibition of TRAP-induced and ADP-induced platelet aggregation and Ca(2+) mobilization. Inhibition was accompanied by activation of PECAM-1. Apart from a slight inhibition by catechin, ethanol or other individual polyphenols failed to inhibit aggregation or activate PECAM-1.

CONCLUSIONS

Red wine inhibits platelet functions through its PGE content, which stimulates the inhibitory receptor PECAM-1, thereby attenuating platelet activation.

Alcohol consumption and platelet activation and aggregation among women and men: the Framingham Offspring Study

BACKGROUND

Alcohol intake has been associated with lower platelet activity; however, few large-scale studies have included women, and to our knowledge, the relationship of alcohol intake with measures of platelet activation has not been studied.

METHODS

We performed a cross-sectional analysis of adults free of cardiovascular disease enrolled in the Framingham Offspring Study. Study physicians assessed alcohol consumption with a standardized questionnaire. We measured platelet activation in response to 1 and 5 microm of adenosine diphosphate (ADP) with a P-selectin assay among 1037 participants and platelet aggregability in response to ADP, epinephrine, and collagen among 2013 participants.

RESULTS

Alcohol consumption was inversely associated with P-selectin expression in response to 1 microm ADP (p = 0.007) and 5 microm ADP (p = 0.02) among men but not women. Alcohol consumption was also inversely associated with platelet aggregation induced by ADP among both women (p = 0.04) and men (p trend = 0.008) and by epinephrine among men (p = 0.03)

CONCLUSIONS

Alcohol consumption is inversely associated with both platelet activation and aggregation, particularly in men. Additional research is needed to determine whether these findings contribute to the contrasting associations of alcohol consumption with risk of thrombotic and hemorrhagic cardiovascular events.

Hemostatic Alterations in Patients With Obstructive Sleep Apnea and the Implications for Cardiovascular Disease *

STUDY OBJECTIVES

Patients with obstructive sleep apnea (OSA) are at increased risk for coronary artery and cerebrovascular diseases. Numerous studies suggest that a hypercoagulable state is prospectively related to atherothrombotic events. This review explores whether changes in hemostasis may constitute one biological link between OSA and vascular disease.

DESIGN

Ten studies on hemostatic variables in OSA were located by electronic library search and descriptively reviewed. Work on hemostatic function with physiologic conditions similar to those found in OSA (hypoxemia and hyperactivity of the sympathetic nervous system) was considered to discuss potential molecular mechanisms of procoagulant disturbances in OSA.

MEASUREMENTS AND RESULTS

The reviewed data suggest that, as compared to non-OSA control subjects, patients with OSA have elevated plasma fibrinogen levels, exaggerated platelet activity, and reduced fibrinolytic capacity. Although not consistently shown, severity of OSA (ie, apnea-hypopnea index) and plasma epinephrine were independent predictors of platelet activity, and average minimal oxygen saturation was an independent predictor of fibrinogen. In some studies, treatment with continuous positive airway pressure decreased platelet activity, plasma fibrinogen levels, and activity of clotting factor VII.

CONCLUSIONS

There is some evidence for a hypercoagulable state in OSA, which might help explain the increased prevalence of vascular diseases in this population. To further confirm such a notion, future studies need to be performed on sufficiently large samples to be able to control for confounders of hemostatic activity. Prospective studies are needed to examine the association between hemostasis molecules and strong vascular end points.

Effect of low doses of ethanol on platelet function in long-life abstainers and moderate-wine drinkers

In vitro, high concentrations of ethanol (EtOH) reduce platelet aggregation. Less is known about the effect of low EtOH doses on platelet function in a selected human population of long-life abstainers and low moderate-wine drinkers to avoid rebound effect of EtOH on platelet aggregation. Results of our experiments suggest that moderate-wine drinkers have higher levels of high density lipoprotein (HDL) than long-life abstainers while fibrinogen levels are unchanged. Furthermore, platelets obtained from these individuals do not differ in their response when stimulated by agonists such as AA and collagen. The effect of in vitro exposure of low doses of EtOH has been studied in PRP and in washed platelets. EtOH (0.1-10 mM) inhibits platelet aggregation induced by collagen at its ED50 while is ineffective when aggregation was triggered by U-46619 and by 1 microM adenosine diphosphate (ADP). 5-10 mM EtOH partially reduces the second wave of aggregation induced by 3 microM ADP. 0.1-10 mM EtOH dose-dependently lowers the aggregation induced by AA at its ED50 but it is less effective at ED75 of AA. The antiaggregating effect of EtOH on aggregation induced by AA is unchanged by inhibitor of nitric oxide synthase. In addition, 10 mM EtOH reduces thromboxane (Tx) formation. In washed platelets, 1-10 mM EtOH partially inhibits platelet aggregation induced by thrombin. In washed resting platelets, 10 mM EtOH does not change the resting [Ca++]i while significantly reduces the increase in [Ca++]i triggered by AA. The results of ex vivo experiments have demonstrated that wine increases the HDL. However, this observation may or may not influence the response of platelets to agonists. Results of our studies demonstrate that low doses of alcohol reduces platelet function.

Platelet CD62p expression and microparticle in murine acquired immune deficiency syndrome and chronic ethanol consumption

AIMS

Abnormal platelet counts have been noticed in acquired immune deficiency syndrome (AIDS) patients. However, the actual state of platelets in AIDS is unclear. We hypothesize that platelets are activated and platelet-derived microparticles increase in murine AIDS.

METHODS

To elucidate the ethanol effects on platelets in murine AIDS, we studied four groups: control, murine AIDS, ethanol, and ethanol plus murine AIDS. Platelet CD62p as a platelet activation marker and CD61(+) microparticles as platelet microparticles (PMPs) were measured by flow cytometry.

RESULTS

Platelets were significantly activated in mice with murine AIDS and chronic ethanol consumption. Increased platelet CD62p expression and increased PMPs were most pronounced in advanced stages of murine AIDS. Chronic ethanol consumption persistently enhanced platelet activation and PMP formation.

CONCLUSIONS

Elevated platelet CD62p and PMPs may represent a pro-thrombotic status that have important pathological consequences.

Alcohol consumption and hemostatic factors: analysis of the Framingham Offspring cohort

BACKGROUND

Moderate alcohol consumers have lower rates of cardiovascular disease than abstainers. One proposed mechanism is a beneficial effect on hemostatic parameters, but previous studies have provided conflicting results.

METHODS AND RESULTS

We measured levels of fibrinogen, plasma viscosity, von Willebrand factor, factor VII, plasminogen activator inhibitor antigen-1, and tissue plasminogen activator antigen in a cross-sectional analysis of 3223 adults free of cardiovascular disease enrolled in the Framingham Offspring Study. We assessed their alcohol consumption with a standardized questionnaire. Light-to-moderate alcohol consumption was associated with lower levels of fibrinogen, plasma viscosity, von Willebrand factor, and factor VII. This association was most pronounced for consumers of 3 to 7 drinks weekly for viscosity and 7 to 21 drinks weekly for the other hemostatic measures. Alcohol intake of 7 to 21 drinks weekly or more was associated with impaired fibrinolytic potential, reflected by higher levels of plasminogen activator inhibitor antigen-1 and tissue plasminogen activator antigen. Wine drinkers had lower plasminogen activator inhibitor antigen-1 levels than other drinkers, particularly at 3 to 21 drinks weekly, but beverage type did not otherwise consistently affect the results.

CONCLUSIONS

Light-to-moderate alcohol consumption is associated with lower levels of coagulatory factors, but higher intake is associated with impaired fibrinolytic potential. These findings are consistent with the hypothesis that a balance between hemostatic and fibrinolytic activity may contribute to the complex relation of alcohol use with coronary heart disease.

Resveratrol decreases early signaling events in washed platelets but has little effect on platelet in whole blood

Resveratrol, a polyphenolic compound found in red wines, is believed to be a contributor in decreasing the incidence of coronary heart disease. Although its primary target is unknown, it blocks aggregation of washed platelets by an ill-defined mechanism. We show that resveratrol, at 10-50 microM, blocked aggregation induced by collagen (5 microg/ml), thrombin (0.2 units/ml), and ADP (10 microM). This affect was not overcome by adding exogenous human fibrinogen to the assay, suggesting that an early (wave I) signaling step in the alpha(IIb)beta(3) activation cascade was impaired. To explore this possibility we examined the effect of resveratrol on activation of MAP kinases. In the platelet, MAP kinases become activated as a consequence of agonist binding and not of aggregation, which itself induces signaling events. In fact, we find that collagen-induced activation of MAP kinases is superinduced in the presence of RGDS, an aggregation-blocking peptide. Resveratrol, at concentrations of 10 microM and greater, inhibited MAP kinase activation induced by collagen (in the absence and presence of RGDS peptide), thrombin, and ADP. These data indicate that resveratrol blocks receptor-mediated signaling events in washed platelets. In comparison, resveratrol has poor antiplatelet activity in whole blood. Under these conditions aggregation was not affected by 50-100 microM resveratrol. Concentrations of 200 microM resveratrol were needed to cause a 30-60% decrease in platelet aggregation in whole blood. Together these studies suggest that resveratrol is a potent inhibitor of platelet signaling responses, but its antiplatelet activity is weakened or masked in circulation. Thus, although resveratrol may function as a protective agent of coronary heart disease, its affects are not solely attributed to its effects on platelets in circulation.

Myocardial protection with red wine extract

Cardioprotective action of red wine was studied by preperfusing isolated rat hearts with ethanol-free red wine extract for 15 min before subjecting them to 30 min of global ischemia followed by 2 h of reperfusion. Four other group of rats were studied under identical conditions, of which one served as control; one was treated with 10 microM trans-resveratrol (RVT), one of the major antioxidants found in red wines; another, with 0.07% ethanol; and another, with 0.07% ethanol plus 10 microM RVT. The results of our study demonstrated that both red wine extract and RVT were equally cardioprotective, as evidenced by their abilities to improve postischemic ventricular functions including developed pressure and aortic flow. Developed pressure values at 60 min after reperfusion were 81.8 +/- 1.2 and 68.8 +/- 4.1 mm Hg for the red wine extract and RVT groups, respectively, versus 49.7 +/- 2.7 mm Hg for the control group. These compounds also reduced myocardial infarct size compared with the control hearts (20.1 +/- 0.5% and 10.5 +/- 0.3% for red wine extract and RVT groups, respectively, vs. 29.9 +/- 3.1% for the control group). The ethanol-treated group displayed slightly better functional recovery, which deteriorated sharply toward the end of the reperfusion period, and the extent of infarction was comparable to that of the control group (31.5 +/- 0.9%). In the ethanol plus RVT group, postischemic contractile function was significantly better than control, and infarct size also was reduced to 20.9 +/- 0.7%. The amount of malonaldehyde formation in the postischemic myocardium was reduced by red wine extract and RVT, indicating a reduction of oxidative stress developed in the ischemic reperfused myocardium. In vitro studies revealed that red wine extract is a potent antioxidant as evidenced by its ability to scavenge peroxyl radical in vitro. Taken together, the results of our study indicate that red wines are cardioprotective by their ability to function as an in vivo antioxidant.

Plasma Concentration of Endogenous Tissue Plasminogen Activator and the Occurrence of Future Cardiovascular Events

Data from recent prospective studies of hemostasis and thrombosis indicate that the plasma concentration of endogenous tissue-type plasminogen activator (tPA) is often elevated years in advance of a first arterial occlusion. Specifically, among healthy subjects with no prior cardiovasacular disease, the risk of future myocardial infarction and stroke appears to be three to four times higher among subjects with high baseline levels of tPA antigen as compared to subjects with lower levels. Whether this relationship represents activation of the endogenous fibrinolytic system in response to the presence of preclinical atherosclerosis or is a reflection of elevated concentrations of local plasminogen activator inhibitors is currently unresolved. However, cross-sectional data indicate that the plasma concentration of IPA antigen is related to several traditional atherosclerotic risk factors, including HDL cholesterol, findings that further support a direct relationship between endogenous IPA and vascular risk. In concert with data concerning the primary inhibitors of plasminogen activation, it has been hypothesizd that the endogenous fibrinolytic system varies within the general population such that certain individuals are prone to thrombosis, whereas others may be prone to hemorrhage. Thus, observations regarding fibrinolytic activation and inhibition raise the possibility that assessment of the intrinsic fibrinolytic system may prove useful in identifying individuals at increased risk for vascular thrombosis. In addition, available findings suggest that therapeutic agents capable of favorably shifting the net filerinolytic balance may provide a new strategy for cardiovascular disease prevention.

The effect of red wine on the fibrinolytic system and the cellular activation reactions before and after exercise

The effect of red wine drinking was tested on fibrinolytic parameters and blood cells in nine healthy students at rest and after acute exercise. The subjects were randomly assigned in a crossover design to one of three treatment regimes: control situation, low-dose wine group, and high-dose wine group. Blood samples were drawn just prior to experimental start, at 2 and 4 hours, and the next morning at 8:00 a.m., at 8:30 a.m. just after exercise, and 2 hours after exercise. The fibrinolytic potential was measured by whole blood clot lysis time (WBCLT), tissue plasminogen activator, and plasminogen activator inhibitor-1 (PAI-1) antigens in plasma. A whole blood system was used to test the reactivity of blood cells by stimulating hirudinized blood with 5 ng/mL lipopolyusaccharide (LPS) for 2 hours at 37 degrees C and measurements of tissue necrosis factor alpha and interleukin-8 (IL-8) in the plasma. Intake of red wine caused impaired fibrinolysis shown by prolonged WBCLT (3.6, 20.7, and 55.7%, respectively, for control, low- and high-dose wine groups) due to increase in PAI-1 antigen (-0.8, 4.8, and 11.0 ng/mL, respectively, in the three groups). There was no effect of the red wine the next morning on the fibrinolytic system. A strong correlation was observed between WBCLT and PAI-1 antigen (p<0.0001). Acute exercise caused an immediate rise in both tissue plasminogen activator antigen and PAI-1 antigen levels and WBCLT was significantly shortened. In contrast to that of the wine groups, 2 hours after exercise WBCLT was prolonged in the control group, but not significantly so. Thus the red wine has a negative effect on the fibrinolytic system during rest, but may have a positive effect after strenuous exercise. The red wine had no immediate effect on LPS-induced tissue necrosis factor alpha or IL-8 production, although there was a tendency for higher cytokine production in the control group compared to the wine groups during and just after intake of wine. The next morning after exercise, the LPS-induced IL-8 production increased 137, 89, and 96%, respectively, in control, low-, and high-dose wine groups, probably due to a rise in epinephrine and activation of platelets. Although not significantly so, there was a tendency for red wine intake in the evening to suppress the reactivity of the cells after physical exercise the subsequent morning. It is suggested that the negative effect of red wine ingestion may be due to the toxic effect of ethanol on hepatocytes or adipose tissue and subsequent release of PAI-1, whereas the positive effect may be due to the red wine suppression of platelet activation and release of PAI-1 from activated platelets. It is proposed that at least part of the beneficial effect of red wine ingestion may be associated with the downregulation of cytokine production.

Moderate alcohol consumption: the gentle face of Janus

OBJECTIVES

The regular consumption of alcohol in moderate amounts (defined in North America as up to 2 drinks per day for men and 1 drink per day for females) has been recognized in the last decade as a negative risk factor for atherosclerosis and its clinical sequelae: coronary heart disease (CHD), ischemic stroke, and peripheral vascular disease. Mortality and morbidity attributable to CHD are 40-60% lower in moderate drinkers than among abstainers. Among the mechanisms accounting for these reductions, increased circulating concentrations of HDL-cholesterol and inhibition of blood coagulation appear to be paramount. Additional benefits are, in certain beverages, conferred by the presence of constituents other than alcohol (e.g., flavonoids and hydroxystilbenes), which prevent oxidative damage, free radical formation, and elements of the inflammatory response.

CONCLUSIONS

A number of other diseases appear to be beneficially modulated by moderate alcohol consumption based on epidemiologic surveys and, in some instances, experimental evidence. These include duodenal ulcer, gallstones, enteric infections, rheumatoid arthritis, osteoporosis, and diabetes mellitus (type II). Compared with abstainers, moderate drinkers exhibit improved mental status characterized by decreased stress and depression, lower absenteeism from work, and decreased incidence of dementia (including Alzheimer's disease). Although limits of safe drinking have been conservatively defined, it is regrettable that political considerations are hampering the clinical application of this knowledge and its dissemination to the lay public.

The red wine antioxidant resveratrol protects isolated rat hearts from ischemia reperfusion injury

The consumption of red wine has been reported to impart a greater benefit in the prevention of coronary heart disease than the consumption of other alcoholic beverages. This beneficial effect is increasingly being attributed to certain antioxidants comprising the polyphenol fraction of red wine such as transresveratrol. In the present study, we investigated the potential cardioprotective effects of resveratrol in the face of ischemia reperfusion (I/R) injury. Isolated perfused working rat hearts after stabilization were perfused with Krebs-Henseleit Bicarbonate buffer (KHB) either in the presence or absence of transresveratrol (RVT) at a concentration of 10 microM for 15 min prior to subjecting them to 30 min of global ischemia followed by 2 h of reperfusion. Left ventricular functions were monitored at various timepoints throughout the reperfusion period to assess the extent of postischemic recovery in comparison with baseline values. Coronary perfusate samples were also collected to determine malonaldehyde (MDA) levels. The results demonstrated that RVT exhibited significant myocardial protection. This was evidenced by improved recovery of post-ischemic ventricular function including developed pressure and aortic flow as compared to the control group (KHB). Values for developed pressure in the RVT-treated group were significantly higher than those in the control group throughout the reperfusion period (71.09+/-4.88 mm Hg vs. 58.47+/-3.88 mm Hg, 68.87+/-5.07 mm Hg vs. 49.74+/-2.65 mm Hg and 51.67+/-3.95 mm Hg vs. 30.50+/-4.80 mm Hg at reperfusion timepoints R-15, R-60, and R-120, respectively). From R-30 onwards, aortic flow was markedly higher in the RVT treated group as compared with the control group, the differences being most significant at R-90 (32.45+/-2.19 ml/min vs. 19.83+/-1.62 ml/min) and R-120 (27.15+/-2.27 ml/min vs. 14.10+/-1.69 ml/min). In contrast to the KHB treated group, the RVT-treated group displayed significant reduction in MDA formation especially in the immediate early reperfusion period (63.71+/-8.19 pM/ml vs. 130.86+/-4.76 pM/ml, 63.84+/-15.62 pM/ml vs. 156.99+/-18.93 pM/ml, 71.29+/-2.80 pM/ml vs. 129.5+/-10.30 pM/ml and 56.25+/-5.79 pM/ml vs. 127.99+/-3.50 pM/ml at timepoints R-1, R-3, R-5, and R-7, respectively) indicating a reduction in I/R injury related oxidative stress. Infarct size was markedly reduced in the RVT group when compared with the control group (10.57+/-0.35% vs. 36.27+/-5.28%). In vitro studies revealed RVT to be a potent scavenger of peroxyl radicals suggestive of a probable mechanism involved in the protective ability of RVT. The results of this study indicate that resveratrol possesses cardioprotective effects which may be attributed to its peroxyl radical scavenging activity.

The effect of moderate alcohol ingestion on blood coagulation and fibrinolysis at rest and in response to exercise

The effect of alcohol ingestion before exercise on blood haemostasis is not known. The present study examined the effects of moderate alcohol ingestion on blood haemostatic variables at rest and in response to exercise. Eleven normal healthy individuals randomly performed two tests separated by 7 days. A moderate dose of ethanol (0.5 g.kg-1) was administered before one test, whereas an equal volume of an alcohol-free drink was administered before the other. Forty-five minutes after the ingestion of either drink, the participants cycled at 65% VO2max for 30 min followed by a 5-min all-out performance. Venous blood samples were obtained before and 45 min after the ingestion of both drinks, and also immediately after exercise. Exercise induced a significant increase in tissue-type plasminogen activator activity and antigen, and factor VIII procoagulant activity. The post-exercise data also showed a significant decrease in plasminogen activator inhibitor activity and soluble fibrin, with a significant shortening in prothrombin time and activated partial thromboplastin time, but not thrombin time. No significant changes were observed in antithrombin III. Although no significant differences were found between trials in the haemostatic and fibrinolytic variables at rest, a significant decrease in fibrinogen concentration was observed after exercise in the alcohol trial. This suggests that ingesting a moderate dose of alcohol does not alter blood coagulation and fibrinolysis at rest. Apart from fibrinogen concentration, which was significantly decreased after exercise in the alcohol trial, most of the haemostatic and fibrinolytic variables were not affected by alcohol. The mechanism responsible for the decrease in fibrinogen following exercise in the alcohol trial remains unknown, but might be related to inhibition of fibrinogen synthesis by the liver or an enhanced rate of its catabolism.

Modulation of haemostatic function and prevention of experimental thrombosis by red wine in rats: a role for increased nitric oxide production

1. The effects of ethyl alcohol and wine (red and white) on haemostatic parameters and experimental thrombosis were studied in rats; NO was evaluated as a possible mediator of these effects. 2. We found that red wine (12% alcohol) supplementation (8.4 +/- 0.4 ml d-1 in drinking water, for 10 days) induced a marked prolongation of 'template' bleeding time (BT) (258 +/- 13 vs 132 +/- 13 s in controls; P < 0.001), a decrease in platelet adhesion to fibrillar collagen (11.6 +/- 1.0 vs 32.2 +/- 1.3%; P < 0.01) and a reduction in thrombus weight (1.45 +/- 0.33 vs 3.27 +/- 0.39 mg; P < 0.01). 3. Alcohol-free red wine showed an effect similar to red wine. In contrast, neither ethyl alcohol (12%) nor white wine (12% alcohol) affected these systems. 4. All these effects were also observed after red wine i.v. injection (1 ml kg-1 of 1:4 dilution) 15 min before the experiments. 5. The effects of red wine were prevented by the NO inhibitor, N omega nitro-L-arginine-methyl ester (L-NAME). L-arginine, not D-arginine, reversed the effect of L-NAME on red wine infusion. 6. Red wine injection induced a 3 fold increase in total radical-trapping antioxidant parameter values of rat plasma with respect to controls, while white wine and alcohol did not show any effect. 7. Our study provides evidence that red wine modulates primary haemostasis and prevents experimental thrombosis in rats, independently of its alcohol content, by a NO-mediated mechanism.

Effects of a single, daily alcoholic beverage on lipid and hemostatic markers of cardiovascular risk

There is substantial epidemiologic data, but limited experimental data, supporting the mortality benefit of low-dose alcohol consumption. A regimen of a single, daily alcoholic beverage was sufficient to increase both high-density lipoprotein (HDL) (4.4%, p = 0.03) and HDL2 (7.7%, p = 0.04) in men and women, but did not significantly affect hemostatic markers of cardiovascular risk.

Diet and haemostasis: time for nutrition science to get more involved

Abnormal haemostasis, and specifically a pre-thrombotic state characterized by hypercoagulability, increased platelet aggregation and impaired fibrinolysis, is associated with increased atheroma and thrombosis. The recent literature clearly indicates that diet may prevent or be used to treat some abnormal haemostatic states. There are reports on effects of energy intake and expenditure, alcohol consumption, intakes of total fat, different fatty acids, fish oil, NSP and vitamins on markers of coagulation, platelet function and fibrinolysis. Some of the confusion and controversy in this field has arisen because the wrong markers of haemostasis have been measured in dietary trials. Moreover, many of the studies have lacked good dietary control. It is suggested that more sensitive, functional markers of the balance between the different facets of the haemostatic system should be measured. It is also important to test hypotheses developed from known observations and to propose mechanisms of action of the various dietary factors, based on our improved understanding of the haemostatic system.

Wines and grape juices as modulators of platelet aggregation in healthy human subjects

To test the hypothesis that red wine, by virtue of its relatively high concentration of polyphenols, is more protective against atherosclerosis and coronary heart disease (CHD) than white wine, and that grape juice enriched in one of these, trans-resveratrol, may share some of these properties, studies were performed on 24 healthy males aged 26-45 years. Each consumed the following beverages for periods of 4 weeks: red wine, white wine, commercial grape juice and the same grape juice enriched with trans-resveratrol. Apart from the last beverage, 2 weeks abstinence was maintained before commencing the schedule. Blood was taken at the beginning and end of each schedule to determine plasma thromboxane B2 (TxB2) concentration and the IC50 (concentration required for 50% aggregation) for ADP and thrombin-induced platelet aggregation. White wine (P < 0.05) but not red wine increased the IC50 for ADP. Both wines increased the IC50 for thrombin (P < 0.02 and P < 0.001, respectively) and also lowered plasma TxB2 concentrations (P < 0.01 and P < 0.025, respectively). Neither grape juice altered ADP-induced aggregation or TxB2 concentrations, but the commercial juice lowered the IC50 for thrombin (P < 0.001) whereas the resveratrol-enriched juice caused a dramatic increase (P < 0.001). In vitro experiments demonstrated that the aggregation of fresh washed human platelets by ADP and thrombin was moderately reduced by both grape juices, strongly by red wine and not at all by white wine. The synthesis of TxB2 by platelets from labelled arachidonate was stimulated by commercial grape juice, slightly enhanced by resveratrol-enriched juice and strongly inhibited by red wine with white wine having little effect. Platelets from subjects consuming the commercial juice had a higher ratio of cyclo-oxygenase to lipoxygenase product formation and those consuming the resveratrol-enriched juice a lower ratio than during the control period. We conclude that trans-resveratrol can be absorbed from grape juice in biologically active quantities and in amounts that are likely to cause reduction in the risk of atherosclerosis. The failure of red wines (which have a 20-fold excess of polyphenols over white wines) to show any advantage suggests that, in vivo, ethanol is the dominant anti-aggregatory component in these beverages which are more potent than grape juices in preventing platelet aggregation in humans.

Inhibitory effect of alcohol on cyclic GMP accumulation in human platelets

The effects of ethanol on cyclic GMP (cGMP) in washed human platelets were studied in the presence and absence of sodium nitroprusside (SNP), nitric oxide donor which stimulates guanylate cyclase. SNP stimulated cGMP accumulation in a dose-dependent fashion. After 1 min exposure to 100 microM SNP, the level of cGMP was approximately four-fold that in vehicle-treated platelets. Alcohol had no effect on basal cGMP, but inhibited SNP-induced cGMP accumulation at 17, 85 and 170 mM. In further experiments, platelets were incubated for 0, 0.5, 1 2 or 5 min with 10 microM SNP, with or without 100 microM zaprinast, a selective cGMP-phosphodiesterase (PDE) inhibitor and 85 mM ethanol. In the presence of zaprinast but not alcohol, cGMP levels rose continuously, to 10-fold the basal level at 5 min. Without zaprinast, cGMP levels were lower and reached a plateau by 2 min. Accumulation of cGMP was attenuated by alcohol 2 and 5 min after SNP addition, both in zaprinast-treated platelets and those without zaprinast. Thus, alcohol inhibits platelet cGMP accumulation stimulated by nitric oxide donor. Its mechanism probably does not involve a major effect on PDE, because the inhibition was observed in the presence or absence of zaprinast. We hypothesize that alcohol inhibits guanylate cyclase, contributing to its complex functional effects in platelets.

Beyond alcohol: beverage consumption and cardiovascular mortality

This paper reviews epidemiological investigations which have identified an inverse relationship between alcohol consumption and death from coronary heart disease: evidence from studies of mixed populations as well as of single-sex populations have, on the whole, demonstrated that this relationship is independent of sex or age. This 'cardioprotective effect' of alcohol can be explained, at least in part, by ethanol-related increases in high density lipoprotein cholesterol and reduced platelet coagulability. With certain beverages, especially red wine, phenolic compounds may provide additional protection by altering eicosanoid metabolism in favour of increased prostacyclin and decreased thromboxane synthesis, as well as antioxidant functions which prevent the peroxidation of low-density lipoprotein. Trans-resveratrol, a tri-hydroxy stilbene present in the skins of specific grape cultivars, is a constituent of certain red wines which may play a crucial role in modulating lipoprotein metabolism, eicosanoid synthesis, oxidation and coagulation. Preliminary studies using the human hepatoma cell line HepG2 are described, demonstrating that this compound has no effect upon cell viability or overall protein synthesis in these cells, and at high concentrations DNA synthesis as measured by radioactive thymidine incorporation is enhanced. Reduced intracellular concentration and secretion of apolipoprotein B have been shown to occur in response to resveratrol although a clear dose-dependency has not yet been demonstrated. The mechanisms underlying these changes as well as the effects upon the synthesis and secretion of other apolipoproteins are under active investigation in our laboratory.

Alcohol and platelet function

Epidemiological studies have shown that moderate consumption of alcoholic beverages is inversely related to the incidence of the complications of coronary artery disease. The protective effect of ethanol may be partially attributable to an inhibitory effect of ethanol on platelets. This article summarizes the experimental observations that ethanol inhibits platelet responses to specific physiological agonists. In alcoholics, various platelet defects have been observed, but these may be influenced by metabolic factors rather than the presence of ethanol alone. The acute effects of ethanol on platelet functions both in vivo and ex vivo will be reviewed. Evidence will be presented demonstrating that ethanol added acutely in vitro inhibits phospholipase A2 in stimulated platelets. The interaction of ethanol with other signal transduction pathways will also be discussed.

Dietary effects on circadian fluctuation in human blood coagulation factor VII and fibrinolysis

Six healthy male volunteers were served 4 strictly controlled isoenergetic diets differing in fat (20% or 50% of energy) and fiber contents (2 or 4 g/MJ) for periods of 2 days. The diets were served in random order with at least 5 days separating each diet period. Blood samples for determination of factor VII clotting activity using human (FVIIc) and bovine thromboplastin (FVIIbt), and for assessment of factor VII antigen (FVIIag), tissue-plasminogen activator (t-PA) antigen, plasminogen activator inhibitor-1 (PAI-1) antigen, PAI activity, t-PA and euglobulin fibrinolytic activity, and triglyceride and insulin levels were collected regularly on the second day of each diet period. The high-fat diets resulted in significantly increased postprandial FVIIbt levels (peak values: 131% vs. 95%, P < 0.01), and higher postprandial FVIIbt/FVIIag ratios (peak values: 1.42 vs. 1.16, P < 0.01) compared with the low-fat diets. Fibrinolytic variables were not affected by the dietary changes and consistently showed characteristic U-shaped (t-PA and PAI-1 antigen, PAI activity), or inverted U-shaped (t-PA and euglobulin fibrinolytic activity) circadian patterns with troughs and peaks, respectively, at 17:30-21:30 h. The dietary fiber content had no significant influence on any of the measured variables. Our findings indicate that high-fat diets may increase blood thrombogenicity by virtue of augmented postprandial activation of factor VII.