A new model to evaluate the diet-induced prothrombotic state, using He-Ne laser-induced thrombogenesis in the carotid artery of apolipoprotein E-deficient and low-density lipoprotein receptor-deficient mice

Global thrombosis test for assessing thrombotic status and efficacy of antithrombotic diet and other conditions

Because of the high mortality from myocardial infarction and stroke, there is a great demand for finding novel methods of diagnosis, prevention and treatment of these diseases. Most of the current tests measure important determinants of thrombosis such as platelet function, coagulation and fibrinolysis in isolation; therefore, a global test measuring the actual thrombotic status would be more useful in clinical conditions. We obtained considerable experience by using the global thrombosis test, which determines the actual thrombotic status by taking into account the measured platelet reactivity, coagulation and fibrinolytic activities. In animal experiments, we found significant correlation between the ex vivo global thrombosis test measurements and the in vivo thrombotic status. The published evidence for the benefit of an antithrombotic diet with regular physical exercise is also described.

There is a great concern in the general population how to detect the risk of thrombotic events and prevent the high mortality from stroke, myocardial infarction, sudden death and cancer-associated thrombosis. Our experience on antithrombotic fruits and vegetables intake and regular exercise assessed by the global thrombosis test suggested a potentially unique way of preventing these life-threatening diseases. In addition, global thrombosis testing may offer some benefit in detecting risk of thrombotic of forthcoming thrombotic events in cancer and COVID-19 virus-infected patients.

Are all wines made from various grape varieties beneficial in the prevention of myocardial infarction and stroke?

Aim:

Epidemiologic studies support the assumption (French paradox hypothesis) that drinking red wine is beneficial in the prevention of cardiovascular diseases. Our recent works however cast doubt on such claim. Earlier we have shown that the antithrombotic activity of various fruits and vegetables mainly depends on their varieties. For this reason, several varieties of red and white grapes were tested for antithrombotic effect in animal experiments.

Results:

Antithrombotic effect of 45 red and white grape varieties were assessed in the present study. Out of the 45, one red grape variety showed antithrombotic effect, while the majority of red and white grape varieties enhanced thrombosis.

Conclusion:

Most red and white grape varieties enhanced thrombotic activity of blood.

Red wine is widely believed to prevent heart attack and stroke as claimed by a French Paradox hypothesis. Antithrombotic effect of 45 grape varieties was measured in the present study. Only very few red and white varieties inhibited the experimentally induced thrombosis while the majority of the tested varieties enhanced thrombotic activity of blood. Thus, our findings challenge the prevailing claims of the French Paradox.

Prevention of thrombotic disorders by antithrombotic diet and exercise: evidence by using global thrombosis tests

Prevention of thrombotic disorders has priority over treatment. There are only two pathologically relevant tests which are suitable for measuring the overall thrombotic status both in experimental conditions and in humans. The Global Thrombosis Test (GTT) and the Global Parallel-Plate Thrombosis Test can detect the pathologically relevant global thrombotic status. These tests have been successfully used for monitoring the effect of antithrombotic drugs and for developing novel antithrombotic agents. By using GTT, varieties of fruits, vegetables, and regular physical exercise have been tested for the effect on global thrombotic status. This review discusses the published evidence for the benefit of diet of selected fruit and vegetable varieties and doing regular physical exercise on improving thrombotic status. Future clinical trials monitored by GTT or Global Parallel-Plate Thrombosis Test could decide on the effectiveness of an experimentally proven antithrombotic diet with regular physical exercise in the prevention of thrombotic diseases.

Short- and long-term treatment with folic acid suppresses thrombus formation in atherogenic mice in vivo

In the present study, we examined the effects of short- and long-term treatment with folic acid (FA) on thrombus formation in vivo in atherogenic mice to explore a novel agent for the prevention of atherothrombotic disease. Apolipoprotein E and low-density lipoprotein receptor double deficient (ApoE(-/-)LDLR(-/-)) mice were orally administrated a single bolus of FA (20mg/kg) or fed an atherogenic diet with or without FA (0.02, 0.5, and 1.5mg/kg) for 12 weeks. Thrombus formation and endothelial function were assessed in vivo using the He-Ne laser-induced carotid artery thrombus formation test and the flow-mediated vasodilation method. Platelet reactivity was assessed ex vivo using haemostatometry. Short-term treatment with FA markedly increased plasma folate levels and significantly suppressed laser-induced thrombus formation in apoE(-/-)LDLR(-/-) mice. Short-term treatment with FA suppressed platelet reactivity in apoE(-/-)LDLR(-/-) mice, but FA treatment did not affect endothelial function or plasma homocysteine levels. Long-term treatment with FA increased plasma folate levels dose-dependently. Thrombus formation and endothelial dysfunction were suppressed by treatment with 0.5 and 1.5mg/kg of FA, respectively, but not with 0.02mg/kg of FA, whereas platelet reactivity was not altered by treatment with any dose of FA. Long-term treatment with all doses of FA decreased the plasma homocysteine levels in apoE(-/-)LDLR(-/-) mice, although this result was not consistent with its anti-thrombotic action. In conclusion, our data showed that short- and long-term treatment with FA could suppress in vivo thrombus formation in an atherogenic setting, independent of its hypohomocysteinemic action.

Mechanism of the experimental antithrombotic effect of some apple varieties involves enhanced endogenous thrombolytic activity

Prevention of arterial thrombotic diseases has high priority in developed countries. As inappropriate diet is known to enhance the risk for acute thrombotic events, a regular diet with experimentally proven antithrombotic effect might be a beneficial way of prevention. The present study is part of a series of investigations testing fruits and vegetables for antithrombotic activity. The Global Thrombosis Test was used to screen sixteen different apple varieties for antiplatelet and thrombolytic activities. The in vitro effective varieties were further investigated using the laser-induced thrombosis model in mice. In order to investigate the mechanism, hemostatometry and flow-mediated vasodilation test (FMV) were performed. Apple varieties were grouped into subclasses according to their antithrombotic activity. AP-2, AP-13, AP-14 and AP-15 showed significant antithrombotic effect both in vitro and in vivo. AP-8 was antithrombotic in vitro but could not determine in vivo because of the shortage of the sample. The antithrombotic effect was mainly due to activation of endogenous thrombolytic mechanism. The mechanism of such enhanced thrombolysis was investigated using a synthetic inhibitor highly specific to plasmin, polyclonal IgG to t-PA and u-PA, and testing the antithrombotic effect in t-PA knockout mice. Antithrombotic activity was prevented by the synthetic plasmin inhibitor and IgG against t-PA but not against u-PA. There was no antithrombotic activity in t-PA knockout mice. Intake of antithrombotic apple filtrate did not affect FMV and platelet reactivity. The antithrombotic effect was heat stable at 100 °C for 10 min. These results suggest that the mechanism of antithrombotic activity involves an increased t-PA release from the vascular endothelium and an inhibition of plasminogen activator inhibitor (PAI-1) release from activated platelets. The present findings justify including antithrombotic apple varieties in an antithrombotic diet.

Experimental antithrombotic effects of sesame seed whole grains and extracts

Prevention of arterial thrombotic diseases has a high priority in developed countries. An inappropriate diet is known to enhance the risks for acute thrombotic events, and nutritional products experimentally shown to be antithrombotic, might contribute beneficial effects. The present study forms part of a series of investigations into the antithrombotic effect of various foods and vegetables. Roasted and crushed whole grains from six varieties of sesame seeds were added to the diet of mice. Antithrombotic activity was measured in the carotid artery in vivo, using a He-Ne laser-induced thrombosis technique after 12 weeks. Col/Chichibu/Maruteru-2/1995 and T016 varieties showed significant antithrombotic activity, whilst 00037803 was prothrombotic. The acute effects of purified ingredients, sesamin, sesamolin and sesamol, given orally or intra-arterially, were also examined after a single dose. The most effective ingredient was sesamol, followed by sesamolin and sesamin. Daily intake of specific antithrombotic sesame whole grains or purified active ingredients might help to prevent atherothrombotic diseases.

Impaired endothelial function may be due to decreased aortic tetrahydrobiopterin, assessed by a new flow-mediated vasodilation in vivo in hypercholesterolemic/atherogenic mice

Tetrahydrobiopterin (BH4) is an important cofactor for endothelial nitric oxide synthase activity. The relationship between endothelial function in vivo and aortic BH4 level is not fully understood, however. In the present study, we aimed to clarify whether reduction of aortic BH4 levels contributes to endothelial dysfunction in vivo using spontaneously hyperlipidemic mice. To estimate endothelial function in vivo and in real-time state, we developed a flow-mediated vasodilation (FMV) method in mice, which measured changes in the diameter of the femoral artery in response to increased blood flow. C57BL/6 mice and apoE/low-density lipoprotein receptor double knock-out mice were fed a low-fat diet (LFD) or a high-fat diet (HFD) for 12 weeks from 6 weeks of age. HFD feeding impaired FMV in double knock-out mice, but not in C57BL/6 mice. Furthermore, HFD feeding reduced plasma NOx concentration and aortic BH4 level in double knock-out mice. Conversely, exogenous injection of BH4 (2 mg/kg) markedly increased aortic BH4 levels and restored endothelial function. In conclusion, we demonstrated that HFD feeding impaired nitric oxide-mediated endothelial function and reduced BH4 level in vivo, and that acute augmentation of aortic BH4 levels improved endothelial function. These findings indicate that BH4 is a critical determinant of nitric oxide-mediated endothelial function in hypercholesterolemia.

The antithrombotic effects of carrot filtrates in rats and mice

The prevention of arterial thrombotic disease has a high priority in developed countries. An inappropriate diet is known to enhance the risk for acute thrombotic events and a regular diet with proven antithrombotic effects might be a beneficial way to prevent disease. The present study was undertaken as a part of a series of investigations to examine vegetables and fruits for antithrombotic activity. A shear-induced in vitro platelet reactivity/thrombolysis method [Global Thrombosis Test, formerly Gorog Thrombosis Test] was used to screen 15 different varieties of carrot for antiplatelet and thrombolytic activities. Effective varieties were further investigated using an in vivo, laser-induced thrombosis model in mice. The different carrot varieties demonstrated a variable effect on thrombosis in vitro and in vivo. In particular, a variety designated SAKATA-0421 exerted an antithrombotic effect in vivo independent from heat treatment of the filtrate at 100 degrees C for 10 min. There was no significant correlation between antithrombotic activity and the levels of polyphenolics and any other biochemical parameter, including antioxidant activity, alpha-carotene and beta-carotene, alpha-tocopherol and ascorbic acid. Different varieties of carrot demonstrated a range of antithrombotic and prothrombotic activities. After oral intake, the particular heat resistant variety (SAKATA-0421) showed antithrombotic effect in vivo possibly due to antiplatelet reactivity and/or spontaneous thrombolytic activity. The present study added a new variety to the list of antithrombotic fruits and vegetables.

Overview of murine thrombosis models

There are a myriad of options on where and how to perform thrombosis studies in mice. Models have been developed for systemic thrombosis, larger and smaller vessels of both the arterial and venous systems as well as several different microvascular beds. However, there are important differences between the models and investigators need to be careful and thoughtful when they choose which model to use.

Murine models of vascular thrombosis (Eitzman series)

Thrombotic complications of vascular disease are the leading cause of morbidity and mortality in most industrialized countries. Despite this, safe and effective drugs targeting these complications are limited, especially in the chronic setting. This is because of the complexity of thrombosis in both arteries and veins, which is becoming increasingly evident as numerous factors are now known to affect the fate of a forming thrombus. To fully characterize thrombus formation in these settings, in vivo models are necessary to study the various components and intricate interactions that are involved. Genetic manipulations in mice are greatly facilitating the dissection of relevant pro- and antithrombotic influences. Standardized models for the study of thrombosis in mice as well as evolving techniques that allow imaging of molecular events during thrombus formation are now available. This review will highlight some of the recent developments in the field of thrombosis using mouse models and how these studies are expanding our knowledge of thrombotic disease.

An experimentally antithrombotic strawberry variety is also effective in humans

Prevention of arterial thrombotic diseases is of high priority in developed countries. As inappropriate diet is regarded as an important risk factor of thrombotic events, daily intake of an antithrombotic diet may offer a convenient and effective way of prevention. Earlier we used animal models of thrombosis to find fruits and vegetables with potential antithrombotic activity. Among various strawberry varieties tested, a particular variety (KYSt-4, Nohime) showed a significant antithrombotic effect. The aim of the present investigation was to extend this study to humans, by testing the experimentally active KYSt-4 and inactive KYSt-10 variety for effectiveness in humans after oral intake. Filtrates of strawberries were prepared and administered orally. Thrombotic status was tested by a novel global test (Gorog Thrombosis Test). The strawberry variety (KYSt-4; Nohime) which earlier inhibited experimental thrombosis showed antithrombotic effects in humans, while the experimentally inactive variety (KYSt-10) as well as the relevant control (water) were ineffective.

Testing various fruits for anti-thrombotic effect: i. Mulberries

Prevention of arterial thrombotic disease has high priority in developed countries. As inappropriate diet predispose to acute thrombotic events, regular intake of an antithrombotic diet may be a convenient and effective way of prevention. The present study was performed to examine antithrombotic effect of mulberry varieties. A shear-induced in vitro platelet reactivity/thrombolysis test (Gorog Thrombosis Test) was used to screen for antiplatelet and thrombolytic activities. In case of effectiveness, it was followed by an in vivo test of laser-induced thrombosis in mice. Antioxidant capacity was assessed by superoxide anion and radical scavenging activities. Total polyphenolics, anthocyanin and citrate contents were also measured. The tested varieties showed different effect in vitro on platelet reactivity and endogenous thrombolytic activity. Varieties inhibiting platelet reactivity were antithrombotic in vivo regardless inhibition or enhancement of thrombolysis. Those mulberry varieties, which enhanced platelet reactivity in vitro, were prothrombotic only if inhibitory activity on endogenous thrombolysis coexisted with the platelet effect. Antioxidant activities and polyphenolics content did not affect platelets and the overall thrombotic status. However, antioxidant activities and polyphenolics content significantly correlated with the endogenous thrombolytic activity. These data showed that mulberry varieties can be grouped into subclasses with either anti- or prothrombotic activities. Antioxidant activities and polyphenolic contents do not affect platelets but may enhance endogenous thrombolysis, thus causing an overall antithrombotic effect.

Mechanism of the Antithrombotic Effect of Dietary Diacylglycerol in Atherogenic Mice

INTRODUCTION

We have shown earlier that diacylglycerol (DAG) but not triacylglycerol (TAG) inhibited thrombus formation. The aim of the present study was to investigate the mechanism of this antithrombotic effect of DAG.

MATERIALS AND METHODS

Four different diets, the (1) Western-style high-fat diet (HFD) containing 20% lipid and 0.05% cholesterol (w/w), (2) TAG-rich and (3) DAG-rich HFDs containing 20% lipid and 0.05% cholesterol, but all lipid replaced by TAG or DAG oil with very similar fatty acid composition and the (4) Japanese-style low-fat diet (LFD) containing 7% oil but no cholesterol were given to apolipoprotein E and low-density lipoprotein (LDL) receptor double-deficient mice. Atherogenicity was assessed by morphology, mapping the whole aorta and measuring the total area of lipid-stained lesions. Endothelial function was measured by the flow-mediated vasodilation test. Platelet reactivity was assessed from native blood sample by a shear-induced platelet function test (hemostatometry). Serum lipoprotein profile was measured by HPLC.

RESULTS

Both the Western-style and the TAG-rich HFDs have accelerated atherosclerosis. In contrast, DAG-rich HFD inhibited the atherosclerotic process to an extent comparable with the Japanese-style LFD. There was no significant difference in platelet and coagulant activity between the studied diet groups. DAG-rich but not the TAG-rich HFD significantly suppressed serum LDL cholesterol level.

CONCLUSIONS

The present findings suggest that the mechanism of antithrombotic and anti-atherogenic effect of DAG may involve the protection of the vascular endothelium from injury and lowered serum LDL cholesterol.

Effect of dietary vegetable and animal proteins on atherothrombosis in mice

OBJECTIVE

It is believed that vegetable and fish, but not animal, proteins prevent thrombosis. The present study compared the effect of long-term intake of purified vegetable and animal proteins (casein, pork, egg white, chicken, white and red fish, soybean, and potato) and powders from whole vegetable and animal meats (soybean, pork, chicken, and horse mackerel) on thrombotic tendency.

METHODS

Western-style high-fat diets with various proteins were given to mice deficient in apolipoprotein-E and low-density lipoprotein receptor for 8 or 12 wk. Thrombotic tendency was assessed by a laser-induced thrombosis test, severity of atherosclerosis was assessed by morphometric analysis of the aortic lesions, and reactivity of platelets was measured by a shear-induced platelet function test.

RESULTS

There was no difference in thrombotic tendency between the vegetable and animal protein diets with the exception of pork protein, which showed a prothrombotic effect. The latter was not observed in animals kept on a high-protein diet. Thrombotic tendency was not affected by preparation of dietary powders from whole pork, chicken, or horse mackerel meats and casein (control), all of which contained the same percentages of protein and lipid. In contrast, soybean powder showed an antithrombotic effect, which was mainly due to an inhibition of atherogenesis rather than to platelet inhibition.

CONCLUSION

Neither the purified animal nor the vegetable protein diet affected thrombotic tendency. Soybean powder inhibited atherothrombosis mainly by inhibiting the atherosclerotic process.

Anti-thrombotic effect of strawberries

Because of the high mortality, prevention of arterial thrombotic disease has top priority in developed countries. As inappropriate diet is known to predispose to acute thrombotic events, regular intake of an anti-thrombotic diet may offer a convenient and effective method of prevention. As part of a systematic investigation into the anti-thrombotic effect of fruits and vegetables, strawberry varieties were tested in this study. An in vitro platelet function test (haemostatometry) was used for screening strawberry filtrates. Those that showed significant antiplatelet effect were further assessed with a laser-induced thrombosis test in mice. Measurement of flow-mediated vasodilation in the femoral artery of mice reflected the effect on the vascular endothelium. Correlation between the effects on platelet reactivity in vitro and the antioxidant activity (hypoxanthine/xanthine oxidase test) or phenolic compound content was assessed. Strawberry varieties KYSt-4 (Nohime), KYSt-11 (Kurume IH-1) and KYSt-17 (Kurume 58) showed significant antiplatelet activity both in vitro and, after oral administration, in vivo. Both KYSt-11 and KYSt-17, but not KYSt-4, significantly reduced flow-mediated vasodilation; that is, caused endothelial dysfunction. Antiplatelet activities were heat stable. Significant correlation was found between antiplatelet and antioxidant activities (P=0.049, R=0.23) or total phenolic compounds (P=0.0096, R=0.36). Of the tested strawberry varieties, KYSt-4, KYSt-11 and KYSt-17 showed significant anti-thrombotic effect. The dual mechanism of the effect may involve a direct inhibition of both platelet function and antioxidant activities.

Endothelial dysfunction precedes atherosclerotic lesions and platelet activation in high fat diet-induced prothrombotic state

INTRODUCTION

Earlier we have demonstrated a prothrombotic state in spontaneously atherogenic rodents kept on Western-style high fat diet. The aim of the present study was to investigate the cellular mechanism of such prothrombotic state.

MATERIALS AND METHODS

Two kinds of diets, Western-style high fat diet containing 20% fat (w/w) and 0.05% cholesterol (w/w) and low fat diet containing 7% fat without cholesterol based on AIN93G, were added to diet-sensitive apolipoprotein E and low-density lipoprotein receptor double deficient male mice for 12 or 18 weeks from 6 weeks of age. Atherosclerosis was assessed by morphometry of the aortic wall or lipid-stained lesions. Endothelial function was measured by flow-mediated vasodilation (FMV) of the femoral artery. Platelet reactivity was measured ex vivo by a shear-induced platelet aggregation test.

RESULTS AND CONCLUSIONS

12 weeks feeding of mice with high fat diet significantly impaired FMV, as compared with mice fed with low fat diet (P<0.05). In contrast, there was no significant difference in the lipid-stained areas and in the reactivity of platelets between the two groups. 18 weeks feeding with high fat diet significantly impaired FMV (P<0.05) and enhanced both lipid-stained areas (P<0.05) and platelet reactivity (P<0.01). These findings show that in high fat diet-induced prothrombotic state, endothelial dysfunction precedes both the morphologically detectable lesions and the enhancement of platelet reactivity.

Dietary diacylglycerol extenuates arterial thrombosis in apoE and LDLR deficient mice

INTRODUCTION

Prevention of arterial thrombotic diseases has high priority in developed countries. An appropriate diet is thought to be the best way to prevent or reduce the risk of mortality from such diseases. The aim of the present study was to evaluate the effect of diacylglycerol (DAG)-rich diets on arterial thrombosis.

MATERIAL AND METHODS

Diet-sensitive congenital apolipoprotein E (ApoE) and LDL receptor (LDLR) double deficient mice were used. Thrombosis was assessed by the rate and extent of thrombus formation in the carotid artery of mice after laser irradiation. Plasma total cholesterol and triglyceride levels were measured by enzymatic assays. Four kinds of diets were used: high fat (Western-style) diet contained 20% fat (w/w) and 0.05% cholesterol (w/w); the TAG-rich and the DAG-rich high fat diet contained 20% TAG or DAG oil (w/w) with very similar fatty acid composition and 0.05% cholesterol ; Low fat (Japanese-style) diet contained 7% fat, without cholesterol. These diets were on the basis of AIN93G and were given to mice for 8 weeks from 6 weeks of age.

RESULTS

Western-style high fat and TAG-rich high fat diets significantly increased thrombogenicity compared with low fat diet. DAG-rich high fat diet showed the lowest value, and the extent of thrombogenicity was equivalent to the low fat diet group. Fasting plasma total cholesterol level of DAG-rich high fat and low fat diet groups were significantly lower than that of TAG-rich high fat and high fat diet groups. Fasting plasma triglyceride levels in DAG-rich high fat diet group were significantly lower than in the TAG-rich high fat diet group.

CONCLUSIONS

Dietary DAG but not TAG oil extenuates arterial thrombus formation. The mechanism of this effect is unclear and further investigated.

Testing various herbs for antithrombotic effect

OBJECTIVE

Prevention of arterial thrombotic diseases has high priority in developed countries. Because people who eat inappropriate food are prone to thrombotic events, regular intake of an antithrombotic diet may offer a convenient and effective way of prevention. The aim of the present study was to find herbs that have antithrombotic effects.

METHODS

Herbs were crushed and centrifuged and the juice obtained was filtered. The effect of filtrate on platelet-rich thrombus formation was assessed by a shear-induced in vitro platelet function test (hemostatometry). Filtrates showing significant antithrombotic activity were further assessed by using a laser-induced in vivo thrombosis test in mice. The effect of orally administered herb filtrates on flow-mediated vasodilation was also measured.

RESULTS

Common thyme and rosemary showed significant antithrombotic activity in vitro and in vivo. Neither herb affected flow-mediated vasodilation.

CONCLUSION

Some herbs possess antithrombotic effects in experimental models of thrombosis. The mechanism of the antithrombotic effect of common thyme and rosemary may involve a direct inhibitory effect on platelets.

An onion variety has natural antithrombotic effect as assessed by thrombosis/thrombolysis models in rodents

INTRODUCTION

Prevention of arterial thrombotic diseases has a high priority in developed countries. As inappropriate diet has been shown to be an important risk factor for thrombotic events, regular antithrombotic diet may offer a convenient and effective way of prevention. The aim of the present study was to test onion extracts for antithrombotic effect and to identify the effective varieties in Allium cepa.

MATERIALS AND METHODS

A shear-induced platelet function test (haemostatometry) was used to screen for antithrombotic potential. Onion extracts showing significant antithrombotic activity in vitro were further assessed in vivo by using a laser-induced thrombosis test in mice.

RESULTS AND CONCLUSIONS

An onion variety, Toyohira, showed significant antithrombotic activity both in vitro and in vivo. Toyohira showed thrombolytic activity in addition to the antiplatelet effect. Superkitamomiji, 2935A, and K83211 showed only thrombolytic activity. Quercetin, the richest flavonoid in onion, was measured, but no correlation was found between quercetin content and antithrombotic activity. It is concluded that onion A. cepa can be classified into varieties with or without antithrombotic and thrombolytic effects. This should be taken into account in future population studies on the antithrombotic effects of vegetables.

Varying the ratio of dietary n−6/n−3 polyunsaturated fatty acid alters the tendency to thrombosis and progress of atherosclerosis in apoE−/− LDLR−/− double knockout mouse

We have investigated the influence of dietary n-6/n-3 (ù-6/ù-3) polyunsaturated fatty acid-balance on the tendency to arterial thrombosis and the progress of atherosclerosis in apoE-/- LDLR-/- double knockout mouse. Homozygous apoE-/- LDLR-/- double knockout mouse (DKO mice, 129XC57BL/6J background) and male C57BL/6 mice aged 6 weeks were divided into four groups. Each group was fed a diet containing a different n-6/n-3 ratio (Group l: 0.29; Group 2: 1.43; Group 3: 5.00; Group 4: 8), prepared with high linolenic (LNA) flaxseed oil (n-3 rich) and high linoleic (LA) safflower oil (n-6 rich). There were no statistical differences in the gain in body weight between the four groups. After 16 weeks, plasma triglyceride and LDL levels in Group 1 were significantly lower than in the other groups. Conversely, HDL was the highest. After 8 and 16 weeks, the tendency to arterial thrombosis was assessed using a He-Ne laser-induced thrombosis model. The degree of atherosclerosis was measured using the entire aorta method employing image analysis software. The n-6/n-3 ratio had a dose-dependent antithrombotic effect (thrombus volume decreased 23%, Group 1 vs. Group 4), In addition, the extent of atherosclerosis was less in the animals fed a low n-6/n-3 ratio compared with the high n-6/n-3 ratio group (atherosclerotic area decreased 40%, Group 1 vs. Group 4). The lowest n-6/n-3 ratio tested (0.29) was the most effective in suppressing the thrombotic and atherosclerotic parameters in these DKO mice.

Anti-thrombotic effect of proanthocyanidin, a purified ingredient of grape seed

INTRODUCTION

Moderate and regular consumption of wine reduces the risk of acute coronary thrombotic events. The mechanism of the anti-thrombotic effect of wine is not clear. Extract or purified ingredients of grapes have not yet been studied for anti-thrombotic effect.

MATERIALS AND METHODS

Anti-thrombotic effect of proanthocyanidin, a highly purified ingredient of grape seed, was assessed by a shear-induced thrombosis test in vitro and by a laser-induced thrombosis test in the mouse carotid artery, in vivo.

RESULTS AND CONCLUSIONS

Intravenously (20 mg/kg body weight, BW) or orally (2 x 200 mg/kg BW) administered proanthocyanidin significantly inhibited the laser-irradiation induced thrombus formation in the carotid artery (both P=0.01). Subsequent to oral administration of proanthocyanidin, in vitro platelet reactivity to shear stress has been inhibited. The latter suggests that the in vivo anti-thrombotic effect of proanthocyanidin may be due to a direct inhibitory effect on platelets.

Effect of trans-resveratrol on the thrombogenicity and atherogenicity in apolipoprotein E-deficient and low-density lipoprotein receptor-deficient mice

Resveratrol is one of the major polyphenolics in red wine that has been shown to exert the preventive effects against cardiovascular diseases. The effect of trans-resveratrol (t-RES) administered as an ingredient of the diet on the atherothrombotic tendency was assessed in genetically hypercholesterolemic mice after laser-induced damage on endothelium. Mice lacking both apolipoprotein E and low-density lipoprotein receptor (apoE-/-/LDLR-/-) were fed with a high-fat diet with or without t-RES (9.6 and 96 mg/kg diet) for 8 weeks. The atherosclerotic tendency was morphometrically analyzed in their aortae. The thrombotic tendency was determined by inducing thrombus by the irradiation of a helium-neon laser on carotid arteries of these mice with injection of Evans blue. Atherosclerotic area and thrombus size were evaluated by image analyzing in a computer system. Even though the plasma concentrations of lipids (total cholesterol and triacylglycerol) did not change in the control and t-RES groups, a significant decrease (approximately 30%) in the formation of atheroma was observed in the aortae of the t-RES group. The size of laser-induced thrombus that mostly consisted of platelet aggregates was significantly reduced (approximately 25%) in the t-RES group compared with that in the control group. Thus, t-RES orally administrated with a high-fat diet in apoE-/-/LDLR-/- mice significantly suppressed atherosclerosis in their aortae and reduced the laser-induced thrombosis in their carotid arteries.

Prebiotics affect nutrient digestibility but not faecal ammonia in dogs fed increased dietary protein levels

An increased protein content and less digestible protein sources in the diet can induce bad faecal odour. The present study investigated the effect of adding prebiotics to dog diets enriched with animal-derived protein sources on apparent digestibilities and faecal ammonia concentration. In three subsequent periods eight healthy beagle dogs were fed a commercial dog diet that was gradually supplemented by up to 50 % with meat and bone meal (MBM), greaves meal (GM) or poultry meal (PM) respectively. Afterwards, 3 % fructo-oligosaccharides or 3 % isomalto-oligosaccharides were substituted for 3 % of the total diet. Supplementation with animal-derived protein sources did not decrease the apparent N digestibility significantly but oligosaccharides did. On the other hand the bacterial N content (% DM) in the faeces was highest in the oligosaccharide groups followed by the protein-supplemented groups and lowest in the control groups. When the apparent N digestibility was corrected for bacterial N no significant differences were noted anymore except for the GM group where the corrected N digestibility was still lower after oligosaccharide supplementation. The amount of faecal ammonia was significantly increased by supplementing with protein or oligosaccharides in the MBM and GM groups but not in the PM group. When apparent N digestibility is interpreted, a correction for bacterial N should be taken into account, especially when prebiotics are added to the diet. Oligosaccharides did not reduce the faecal ammonia concentrations as expected.

Tomatoes have natural anti-thrombotic effects

The prevention of arterial thrombotic diseases has a high priority in developed countries. An inappropriate diet may be an important risk factor for thrombotic events. The daily intake of an anti-thrombotic diet may offer a convenient and effective way of prevention. The aim of the present study was to test tomato extracts for anti-thrombotic effects and to identify those varieties that have such an effect. A shear-induced platelet-function test (haemostatometry) was used to test anti-thrombotic potential in vitro. Extracts from those tomato varieties that showed a significant anti-thrombotic activity in vitro were further assessed in vivo, using a laser-induced thrombosis test in mice. One tomato variety (KG99-4) showed significant anti-thrombotic activity both in vitro and in vivo. KG99-4 inhibited not only platelet-rich thrombus formation but also had a thrombolytic effect. It is concluded that haemostatometry can detect and classify the anti-thrombotic potential of fruits and vegetables and offers a simple way of screening for such effects.

Antithrombic and anti-atherogenic effects of partially defatted flaxseed meal using a laser-induced thrombosis test in apolipoprotein E and low-density lipoprotein receptor deficient mice

Atherothrombosis can be regarded as a 'life-style related disease' of which diet is one of the important risk factors. The prophylactic effect of partially defatted flaxseed meal (PDFM) on atherothrombosis has not yet been studied. The aim of this study was to assess the effect of PDFM and a lignan from flaxseed, secoisolariciresinol diglucoside (SDG), on thrombosis and atherogenesis. An earlier developed test, the quantitative assessment of laser-induced thrombus formation in the carotid artery of apolipoprotein E and low-density lipoprotein receptor deficient mice was used in this study. Thrombotic and atherosclerotic status was assessed in mice kept on a high-fat diet for 8 weeks (40% in energy). The diet contained 0.05% cholesterol alone (control) or the same cholesterol with added PDFM (5% w/w; 8.3 g/kg body weight per day) or SDG (0.06% w/w; 100 mg/kg body weight per day). PDFM showed antithrombotic (P < 0.01) and anti-atherogenic effect (P < 0.01). SDG did not affect either atherogenesis or thrombosis. This study suggests that dietary intake of PDFM can be beneficial in reducing the risk of high-fat-induced atherothrombosis.