Association between high plasma levels of legumain and cardiovascular events in patients undergoing coronary angiography.

Degradation of vascular extracellular matrix is important in atherosclerosis. Cysteine protease legumain is upregulated in atherosclerotic plaques. We recently reported that plasma legumain levels are high in patients with complex coronary lesions. This study investigated the association between legumain levels and cardiovascular events in 372 patients undergoing coronary angiography. Patients with acute coronary syndrome were excluded. Of the 372 patients, 225 had coronary artery disease (CAD). During a mean follow-up of 7.0 ± 4.3 years, cardiovascular events occured in 62 patients. Compared with 310 patients without events, 62 with events tended to have higher prevalence of complex lesions (15% vs. 10%). Notably, patients with events had higher legumain levels (median 5.51 vs. 4.90 ng/mL, P < 0.01) than those without events. A Kaplan-Meier analysis showed lower event-free survival in patients with legumain > 5.0 ng/mL than in those with ≤ 5.0 ng/mL (P < 0.01). In multivariate Cox regression analysis, legumain level was an independent predictor of cardiovascular events. The hazard ratio for legumain > 5.0 ng/mL for cardiovascular events was 2.18 (95%CI = 1.27-3.77, P < 0.01). Only among 225 patients with CAD, patients with events had higher legumain levels (5.49 vs. 4.73 ng/mL) than without events (P < 0.02). Legumain level was also a predictor of cardiovascular events in patients with CAD. Thus, high plasma legumain levels were associated with an increased risk of cardiovascular events in patients undergoing coronary angiography and those with stable CAD.

High plasma levels of endosialin and cardiovascular events in patients undergoing coronary angiography.

Endosialin, also known as tumor endothelial marker-1, is a transmembrane glycoprotein that plays a role in inflammation and tumor progression. Endosialin is upregulated in atherosclerotic lesions. To elucidate the association between blood endosialin levels and cardiovascular events, we measured plasma endosialin levels in 389 patients undergoing coronary angiography who were followed up for a mean follow-up of 6.4 ± 4.2 years for cardiovascular events (cardiovascular death, myocardial infarction, unstable angina, heart failure, stroke, or need for coronary revascularization). Of the 389 patients, 223 had coronary artery disease (CAD). No significant difference was found in plasma endosialin levels between patients with and without CAD (median 0.92 vs. 0.92 ng/mL). During the follow-up, cardiovascular events occurred in 62 patients. Compared with patients without events, those with events had higher endosialin levels (1.12 vs. 0.89 ng/mL), and more often had endosialin level of > 1.1 ng/mL (53% vs. 31%) (P < 0.01). A Kaplan-Meier analysis showed lower event-free survival in patients with endosialin > 1.1 ng/mL than those with ≤ 1.1 ng/mL (P < 0.01). In a multivariate Cox regression analysis, endosialin > 1.1 ng/mL was an independent predictor of cardiovascular events (hazard ratio = 2.00; 95%CI = 1.21-3.32; P < 0.01). Thus, high plasma endosialin levels were associated with an increased risk of cardiovascular events in patients undergoing coronary angiography.

High plasma concentrations of vanin-1 in patients with coronary artery disease.

Vanin-1 is a pantetheinase that hydrolyzes pantetheine to pantothenic acid and cysteamine. Vanin-1 has become recognized to be associated with oxidative stress and inflammation. In animal models, vanin-1 was reported to accelerate atherosclerosis. However, no study has reported blood vanin-1 concentrations in patients with coronary artery disease (CAD). We investigated plasma vanin-1 concentrations in 388 patients undergoing elective coronary angiography for suspected CAD. Patients with acute coronary syndrome were excluded. Of the 388 study patients, CAD was found in 207 patients [1-vessel (1-VD), n = 88; 2-vessel (2-VD), n = 66; and 3-vessel disease (3-VD), n = 53]. Plasma vanin-1 concentrations were higher in patients with CAD than in those without CAD (median 0.59 vs. 0.46 ng/mL, P < 0.005). Vanin-1 concentrations in patients without CAD and those with 1-VD, 2-VD, and 3-VD were 0.46, 0.58, 0.57, and 0.61 ng/mL, respectively, and were highest in 3-VD (P < 0.05). A high vainin-1 concentration (> 0.48 ng/mL) was found in 46% of patients without CAD, 61% of 1-VD, 65% of 2-VD, and 66% of 3-VD (P < 0.01). Vanin-1 concentrations significantly correlated with the number of stenotic coronary segments (r = 0.14, P < 0.02). In the multivariate analysis, vanin-1 concentration was a significant factor associated with CAD independent of atherosclerotic risk factors. The odds ratio for CAD was 1.63 (95%CI = 1.04-2.55) for the high vanin-1 concentration of > 0.48 ng/mL. Thus, plasma vanin-1 concentrations in patients with CAD were found to be high and to be associated with the presence and severity of CAD.

No Significant Association Between Plasma Endosialin Levels and the Presence or Severity of Coronary Artery Disease.

Background: Endosialin, also called tumor endothelial marker-1 or CD248, is a transmembrane glycoprotein that is suggested to play a role in inflammation as well as tumor progression. Endosialin expression was also reported to be upregulated in human atherosclerotic lesions. However, no study has reported blood endosialin levels in patients with coronary artery disease (CAD). Methods: We investigated the association between plasma endosialin levels and the presence or severity of CAD in 376 patients who underwent elective coronary angiography for suspected CAD. The severity of CAD was represented as the numbers of stenotic coronary vessels and segments. Results: Of the 376 study patients, CAD was found in 210 patients (one-vessel disease (1-VD), n = 90; two-vessel disease (2-VD), n = 65; and three-vessel disease (3-VD), n = 55). Compared with 166 patients without CAD, 210 patients with CAD had higher C-reactive protein (CRP) levels (median 0.57 vs. 0.43 mg/L, P = 0.007). However, endosialin levels did not significantly differ between patients with and without CAD (0.91 vs. 0.92 ng/mL, P = 0.693). A stepwise increase in CRP levels was found depending on the number of > 50% stenotic vessels: 0.43 in CAD(-), 0.52 in 1-VD, 0.57 in 2-VD, and 0.58 mg/L in 3-VD (P = 0.019). No marked difference was found in endosialin levels among four groups of CAD(-), 1-VD, 2-VD, and 3-VD (0.92, 0.89, 0.98, and 0.87 ng/mL, respectively, P = 0.785). Moreover, no significant correlation was found between endosialin levels and the numbers of > 50% and > 25% stenotic segments or CRP levels. In multivariate analysis, endosialin levels were not a significant factor associated with CAD independent of atherosclerotic risk factors. Conclusions: Plasma endosialin levels in patients with CAD were found to be not higher than in those without CAD and to be not significantly associated with the presence or severity of CAD.

Associations between Green Tea Consumption and Coffee Consumption and the Prevalence of Coronary Artery Disease.

Green tea and coffee contain various bioactive compounds (e.g., polyphenols), and their consumption has been proposed to decrease the risk of cardiovascular diseases. Here, we investigated the associations between the consumption of green tea and that of coffee and the prevalence of coronary artery disease (CAD) in Japanese patients. The study group was 612 patients who underwent coronary angiography at Tokyo Medical Center between July 2008 and February 2017. CAD was confirmed in 388 of the patients: one-vessel disease (1-VD, n=166); two-vessel disease (2-VD, n=112); three-vessel disease (3-VD, n=110). Myocardial infarction (MI) was found in 138 patients. After adjustment for well-known atherosclerotic risk factors and other dietary habits, greater green tea consumption was significantly inversely associated with CAD prevalence (p for trend=0.044), and the patients who drank >3 cups/d had a lower prevalence of CAD compared to those who drank <1 cup/d (odds ratio [OR]: 0.54, 95% CI: 0.30-0.98). Greater green tea consumption (>3 cups/d) was also associated with a decreased prevalence of 3-VD (OR: 0.49, 95% CI: 0.24-0.98, p-trend=0.047) and MI (OR: 0.51, 95% CI: 0.27-0.97, p-trend=0.037). In contrast, coffee consumption was not associated with CAD or MI. In subgroup analyses, the inverse association between green tea consumption and CAD or MI was found in the high intake groups of vegetables or fruits but not in the low intake groups of vegetables or fruits. These results suggest a beneficial effect of green tea consumption, especially with a diet rich in vegetables and fruits, against coronary atherosclerosis in Japanese.

High Plasma Levels of Legumain in Patients with Complex Coronary Lesions.

AIM: The degradation of the vascular extracellular matrix is important for atherosclerosis. The cysteine protease legumain was shown to be upregulated in atherosclerotic plaques, especially unstable plaques. However, no study has reported blood legumain levels in patients with coronary artery disease (CAD). METHODS: We investigated plasma legumain and C-reactive protein (CRP) levels in 372 patients undergoing elective coronary angiography. RESULTS: CAD was found in 225 patients. Compared with patients without CAD, those with CAD had higher CRP levels (median 0.60 [0.32, 1.53] vs. 0.46 [0.22, 0.89] mg/L, P＜0.001), but no difference was found in legumain levels between patients with and without CAD (median 5.08 [3.87, 6.82] vs. 4.99 [3.84, 6.88] ng/mL). A stepwise increase in CRP was found depending on the number of ＞50% stenotic vessels: 0.55 mg/L in 1-vessel, 0.71 mg/L in 2-vessel, and 0.86 mg/L in 3-vessel diseases (P＜0.001). However, legumain did not differ among 1-, 2-, and 3-vessel diseases (5.20, 4.93, and 5.01 ng/mL, respectively). Of 225 patients with CAD, 40 (18%) had complex lesions. No difference was found in CRP levels between patients with CAD with and without complex lesions (0.60 [0.34, 1.53] vs. 0.60 [0.32, 1.51] mg/L). Notably, legumain levels were higher in patients with CAD with complex lesions than without such lesions (6.05 [4.64, 8.64] vs. 4.93 [3.76, 6.52] ng/mL, P＜0.01). In multivariate analysis, legumain levels were not a factor for CAD, but were a factor for complex lesions. The odds ratio for complex lesions was 2.45 (95% CI=1.26-4.79) for legumain ＞5.5 ng/mL. CONCLUSION: Plasma legumain levels were associated with the presence of complex coronary lesions.

Plasma Betatrophin Levels and Carotid Atherosclerosis.

AIMS: Betatrophin is a recently identified circulating adipokine that may affect lipid and glucose metabolism. However, the association between plasma betatrophin levels and carotid atherosclerosis has not been elucidated. METHODS: We investigated plasma betatrophin levels in 153 subjects undergoing carotid ultrasonography. The severity of plaque was evaluated as plaque score. RESULTS: Of the 153 subjects, plaque was found in 63 (41%). Plasma betatrophin levels were higher in 63 subjects with plaque than in 90 without plaque (median 906 vs. 729 pg/mL, P < 0.025). A stepwise increase in betatrophin levels was found depending on the plaque score: 729 pg/mL in score = 0 (n = 90), 802 pg/mL in score = 1 (n = 31), and 978 pg/mL in score ≥ 2 (n = 32) (P < 0.01). In particular, betatrophin levels in subjects with score ≥ 2 were higher than in those with score = 0 (P < 0.05). Moreover, betatrophin levels correlated with plaque score (r = 0.23, P < 0.01), but no significant correlation was found between betatrophin levels and triglyceride or HbA1c levels. The percentage of subjects with betatrophin > 800 pg/mL was higher in subjects with plaque than in those without plaque (65% vs. 44%) and was highest in score ≥ 2 (78%) (P < 0.005). In the multivariate analysis, betatrophin level was not a significant factor for the presence of plaque but was a significant factor for plaque score ≥ 2, independent of atherosclerotic risk factors. The odds ratio for score ≥ 2 was 4.9 (95% CI = 1.9-12.8) for betatrophin > 800 pg/mL. CONCLUSIONS: Plasma betatrophin levels were found to be high in subjects with carotid plaque and to be associated with the severity of plaque. Betatrophin may play a role in the progression of carotid atherosclerosis.

Aronia berry extract inhibits TNF-α-induced vascular endothelial inflammation through the regulation of STAT3.

BACKGROUND: Inflammation in endothelial cells induces production of inflammatory cytokines and monocytes adhesion, which are crucial events in the initiation of atherosclerosis. Aronia berry (Aronia meranocalpa), also called black chokeberry, contains abundant anthocyanins that have received considerable interest for their possible relations to vascular health. OBJECTIVE: The aim of this study was to investigate whether an anthocyanin-rich extract obtained from aronia berry can attenuate inflammatory responses in vascular endothelial cells. METHODS: As a model of vascular endothelial inflammation, human umbilical vein endothelial cells (HUVECs) pretreated with aronia berry extract were stimulated with tumor necrosis factor-alpha (TNF-α). The expression levels of cytokines and adhesion molecules were analyzed. To investigate the effects of aronia berry extract on the adhesion of THP-1 monocytic cell, the static adhesion assay was carried out. The possible molecular mechanisms by which aronia berry extract regulated vascular inflammatory responses were explored. RESULTS: The mRNA expressions of interleukins (IL-1ß, IL-6, and IL-8) and monocyte chemoattractant protein-1 (MCP-1) upregulated by TNF-α were significantly suppressed by pretreatment with aronia berry extract. Aronia berry extract decreased TNF-α-induced monocyte/endothelial adhesion and suppressed vascular cell adhesion molecule-1 (VCAM-1) expression, but did not affect intercellular adhesion molecule-1 (ICAM-1) expression. Moreover, aronia berry extract decreased the phosphorylation of signal transducer and activator of transcription 3 (STAT3) and the nuclear levels of STAT3 and interferon regulatory transcription factor-1 (IRF1). The nuclear translocation of nuclear factor-kappa B (NF-κB) was not inhibited by aronia berry extract. CONCLUSION: Aronia berry extract could exert anti-atherosclerotic effects on TNF-α-induced inflammation through inhibition of STAT3/IRF1 pathway in vascular endothelial cells.

Associations Between Plasma Betatrophin Levels and Coronary and Peripheral Artery Disease.

AIM: Betatrophin, a recently identified circulating adipokine, affects lipid and glucose metabolism. However, association between plasma betatrophin levels and atherosclerotic diseases, such as coronary artery disease (CAD) and peripheral artery disease (PAD), has not been elucidated. METHODS: We investigated plasma betatrophin levels in 457 patients undergoing elective coronary angiography who also had ankle-brachial index (ABI) test for PAD screening. RESULTS: Of the 457 study patients, CAD was present in 241 patients (53%) (1-vessel [1-VD], n=99; 2-vessel [2-VD], n=71; 3-vessel disease [3-VD], n=71). Compared to 216 patients without CAD, 241 with CAD had higher betatrophin levels (median 1120 vs. 909 pg/mL, p＜0.001). A stepwise increase in betatrophin levels was found depending on the number of ＞50% stenotic coronary vessels: 909 in CAD(-), 962 in 1-VD, 1097 in 2-VD, and 1393 pg/ml in 3-VD (p＜0.001). Betatrophin levels correlated with the number of ＞25% stenotic segments (r=0.24, p＜0.001). PAD (ABI＜0.9) was found in 41 patients (9%). Plasma betatrophin levels were also significantly higher in 41 patients with PAD than in 416 without PAD (1354 vs. 981 pg/mL, p＜0.001). In the multivariate analysis, betatrophin levels were not a factor for CAD, but they were a significant factor for 3-VD and PAD independent of atherosclerotic risk factors. The odds ratios for 3-VD and PAD were 1.06 (95%CI=1.01-1.11) and 1.07 (95%CI=1.01-1.13) for a 100-pg/mL increase in betatrophin levels, respectively (p＜0.05). CONCLUSION: Plasma betatrophin levels were associated with the presence and severity of CAD and PAD, suggesting betatrophin has a role in atherosclerosis.

Dietary Polyphenol Intake Estimated by 7-Day Dietary Records among Japanese Male Workers: Evaluation of the Within- and Between-Individual Variation.

Polyphenol intake has been estimated in some populations; however, information about day-to-day and individual differences in polyphenol intake has not been well-evaluated. In this study, we aimed to examine within- and between-individual variation in polyphenol intake in Japanese male workers. First, 56 male subjects (aged 37.9±10.4 y) completed detailed 7-d dietary records (DR). We then calculated their total polyphenol intake using our polyphenol content database and the within- and between-individual variations. We also estimated the minimum number of days of dietary assessment required both to rank individuals within a group and to assess an individual's usual polyphenol intake with acceptable accuracy. The estimated daily total polyphenol intake was 965±471 mg/d, which was largely sourced from beverages. The day-to-day variation (CVw) for polyphenol intake was 43.6%, and the variation between the individuals in the population (CVb) for polyphenol intake was 45.9%. A 4-d DR was required to rank individuals within a group with high correlation coefficients (r=0.9), and a 19-d DR was required to assess the individual's usual polyphenol intake with 20% deviation. The CVw for polyphenol intake was intermediate between those of the other nutrients, but the CVb for polyphenol intake was largest among the nutrients. These results suggest that the dietary intake of polyphenols should be carefully estimated considering its within- and between-individual variation.

The Effect of the Consumption of Egg on Serum Lipids and Antioxidant Status in Healthy Subjects.

The egg is a nutrient-dense food and contains a number of antioxidants. The consumption of eggs has been considered to improve the balance of diets, although its impact on serum cholesterol levels has been a matter of concern in many countries. Here, we conducted a pilot study to investigate whether daily additional consumption of an egg might affect serum lipid profiles and also antioxidant status in healthy subjects. Fourteen male subjects were provided with breakfasts including a boiled egg for 4 wk. At the end of intervention, serum concentrations of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) were unchanged, despite the significant increase in the intake of dietary cholesterol. In contrast, a significant increase in high-density lipoprotein cholesterol (HDL-C) and a reduction of the LDL-C/HDL-C ratio were observed. Interestingly, the malondialdehyde modified-LDL (MDA-LDL)/LDL-C ratio and the oxidizability of LDL were significantly reduced. Serum total antioxidant capacity value after the intervention period was higher than at baseline. These data indicate that consuming one egg per day for 4 wk as breakfast in addition to a normal diet does not affect serum lipids, and suggests that it may improve serum antioxidant status in healthy males.

Terminalia bellirica Extract Inhibits Low-Density Lipoprotein Oxidation and Macrophage Inflammatory Response in Vitro.

The deciduous tree Terminalia bellirica found in Southeast Asia is extensively used in traditional Indian Ayurvedic medicine for the treatment of hypertension, rheumatism, and diabetes. The anti-atherogenic effect of Terminalia bellirica fruit has not been fully elucidated. Here, we investigated the effect of Terminalia bellirica extract (TBE) on low-density lipoprotein (LDL) oxidation and inflammation in macrophages. TBE showed 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (EC50: 7.2 ± 1.2 µg/mL) and 15-lipoxygenase inhibitory activity. TBE also significantly inhibited free radical-induced LDL oxidation compared to the solvent control in vitro. In THP-1 macrophages, TBE treatment resulted in significant decreases of the mRNA expression of tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1ß), and lectin-like oxidized LDL receptor-1 (LOX-1). TBE also reduced matrix metalloproteinase (MMP)-9 secretion and intracellular reactive oxygen species (ROS) production in THP-1 macrophages. These results show that TBE has the inhibitory effects on LDL oxidation and macrophage inflammatory response in vitro, suggesting that its in vivo use might inhibit atherosclerosis plaque progression.

Green tea catechins prevent low-density lipoprotein oxidation via their accumulation in low-density lipoprotein particles in humans.

Green tea is rich in polyphenols, including catechins which have antioxidant activities and are considered to have beneficial effects on cardiovascular health. In the present study, we investigated the effects of green tea catechins on low-density lipoprotein (LDL) oxidation in vitro and in human studies to test the hypothesis that catechins are incorporated into LDL particles and exert antioxidant properties. In a randomized, placebo-controlled, double-blind, crossover trial, 19 healthy men ingested green tea extract (GTE) in the form of capsules at a dose of 1 g total catechin, of which most (>99%) was the gallated type. At 1 hour after ingestion, marked increases of the plasma concentrations of (-)-epigallocatechin gallate and (-)-epicatechin gallate were observed. Accordingly, the plasma total antioxidant capacity was increased, and the LDL oxidizability was significantly reduced by the ingestion of GTE. We found that gallated catechins were incorporated into LDL particles in nonconjugated forms after the incubation of GTE with plasma in vitro. Moreover, the catechin-incorporated LDL was highly resistant to radical-induced oxidation in vitro. An additional human study with 5 healthy women confirmed that GTE intake sufficiently increased the concentration of gallated catechins, mainly in nonconjugated forms in LDL particles, and reduced the oxidizability of LDL. In conclusion, green tea catechins are rapidly incorporated into LDL particles and play a role in reducing LDL oxidation in humans, which suggests that taking green tea catechins is effective in reducing atherosclerosis risk associated with oxidative stress.

Estimated Dietary Polyphenol Intake and Major Food and Beverage Sources among Elderly Japanese.

Estimating polyphenol intake contributes to the understanding of polyphenols' health benefits. However, information about human polyphenol intake is scarce, especially in the elderly. This study aimed to estimate the dietary intake and major sources of polyphenols and to determine whether there is any relationship between polyphenol intake and micronutrient intake in healthy elderly Japanese. First, 610 subjects (569 men, 41 women; aged 67.3 ± 6.1 years) completed food frequency questionnaires. We then calculated their total polyphenol intake using our polyphenol content database. Their average total polyphenol intake was 1492 ± 665 mg/day, the greatest part of which was provided by beverages (79.1%). The daily polyphenol intake differed largely among individuals (183-4854 mg/day), also attributable mostly to beverage consumption. Coffee (43.2%) and green tea (26.6%) were the major sources of total polyphenol; the top 20 food items accounted for >90%. The polyphenol intake did not strongly correlate with the intake of any micronutrient, suggesting that polyphenols may exert health benefits independently of nutritional intake. The polyphenol intake in this elderly population was slightly higher than previous data in Japanese adults, and beverages such as coffee and green tea contributed highly to the intake.

Polyphenol Intake from Beverages in Japan over an 18-Year Period (1996-2013): Trends by Year, Age, Gender and Season.

An association between the dietary intake of polyphenols and human health has been shown in many epidemiological studies. Since beverages are rich sources of polyphenols, we aimed to evaluate the polyphenol intake from beverages in Japanese individuals with a focus on differences according to year, age, gender and season. More than 10,000 Japanese male and female subjects aged 1-99 y old participated in this survey every year from 1996 to 2013, and their beverage consumption and amount of polyphenol intake were calculated. Polyphenol intake from beverages in Japan showed no tendency to increase or decrease over the 18-y period, and the major sources of polyphenols in Japanese daily life were coffee and green tea. Polyphenol intake was larger in participants with higher age up to 59 y old in both male and female subjects. There was a slight difference in polyphenol intake by gender, with adult males consuming more polyphenols than adult females. Polyphenols were consumed slightly more in the winter than the summer, although the seasonal difference in polyphenol intake was not large. Our results suggest that polyphenol intake from beverages is influenced by age rather than gender or season in Japan, and may not have changed over time, at least over the 18-y period beginning in 1996 in Japan.

Anti-Inflammatory Diet for Atherosclerosis and Coronary Artery Disease: Antioxidant Foods.

Oxidative stress plays a role in atherosclerotic diseases such as coronary artery disease (CAD), and much attention has been paid to antioxidant foods. The relationships between the consumption of vegetables and fruits and atherosclerotic diseases have been reported in many epidemiological studies showing a reduced risk of such diseases. In addition to the antioxidant vitamins C and E, green and yellow vegetables contain abundant quantities of carotenoids and polyphenols. The consumption of carotenoids and vitamins C and E has been shown to be inversely associated with CAD. However, supplementation with beta-carotene and vitamins C and E shows no beneficial effect, but rather mortality is increased with beta-carotene and vitamin E supplements. Therefore, it is recommended to consume vegetables and fruits, but vitamin supplementation is not recommended. Many epidemiological studies also report that higher consumption of fish, rich in n-3 polyunsaturated fatty acids (PUFAs), is associated with a lower risk of CAD and stroke. Antiatherosclerotic effects of n-3 PUFAs include reduced platelet aggregation, triglyceride-lowering effect, anti-inflammatory effect, and plaque stabilization, but the anti-inflammatory effect is principally responsible for preventing atherosclerosis. It is recommended to consume fish at least twice a week in patients without CAD and to consider n-3 PUFA supplements in patients with documented CAD. Regarding soy products, soy protein consumption reduces low-density-lipoprotein cholesterol and triglyceride levels. Isoflavone, a polyphenol contained in soybeans, has antiatherosclerotic property because it has a structure similar to that of estrogen and bonds with estrogen receptors. High consumption of isoflavone has been reported to be associated with a reduced risk of CAD and stroke only in women, but the preventative effect of soy products in the general population has not yet been clarified. Thus, many epidemiological studies report the promising effects of antioxidant foods, but there are many unclear points remaining with regard to the contribution of the nutritional elements found in antioxidant foods to the prevention of atherosclerotic diseases.

Pine bark extract prevents low-density lipoprotein oxidation and regulates monocytic expression of antioxidant enzymes.

Polyphenols are widely distributed in leaves, seeds, bark, and flowers and considered to have beneficial effects on cardiovascular health. We hypothesized that the potent antioxidant properties of pine bark extract (PBE) are exerted by its ability to scavenge free radicals and induce antioxidant enzymes. Therefore, we investigated the effects of PBE on low-density lipoprotein (LDL) oxidation and the antioxidant defense system in monocytes. Oxidative susceptibility of LDL was determined by lag time assay in vitro and by using a human umbilical vein endothelial cell-mediated oxidation model. THP-1 monocytic cells were treated with PBE, and the expression of antioxidant enzymes was measured by real-time polymerase chain reaction and Western blot. Pine bark extract showed radical scavenging ability and significantly inhibited free radical-induced and endothelial cell-mediated LDL oxidation in vitro. Pine bark extract treatment resulted in increases in the expressions of antioxidant enzymes, glutathione peroxidase-1, catalase, and heme oxygenase-1 in THP-1 cells. In addition, PBE induced nuclear factor-erythroid-2-related factor 2 activation, which was accompanied by the activation of extracellular signal-regulated kinase and Akt despite a down-regulation of reactive oxygen species. After the monocyte investigations, we further examined the antioxidant effect after the intake of PBE by 10 healthy male volunteers. Pine bark extract significantly prolonged the lag time of LDL oxidation. Based on our findings, it appears that PBE enhances the antioxidant defense capacity of LDL and monocytes and may play a preventive role in atherosclerosis progression.

Antioxidant activities of Perilla frutescens against low-density lipoprotein oxidation in vitro and in human subjects.

Perilla (Perilla frutescens (L.) Britt.) is a popular food as well as a traditional medicine in Japan, China, and other Asian countries. The aim of this study was to investigate the inhibitory effects of perilla on low-density lipoprotein (LDL) oxidation in vitro and in human subjects. We compared the antioxidant activities of red perilla and green perilla. Both green and red perilla had high 1,1-diphenyl-2-picrylhydrazyl radical scavenging activities and were abundant in polyphenol compounds. In addition, the radical scavenging activity and polyphenol content of red perilla were higher than those of green perilla. Perilla dramatically inhibited azo-radical-induced LDL oxidation and endothelial-cell-mediated LDL oxidation in vitro. Moreover, red perilla significantly increased mRNA and protein expression levels of antioxidant enzymes in endothelial cells. We further examined the antioxidant effects against LDL in human subjects after the consumption of perilla extracts. After oral intake of red perilla, the subjects' LDL oxidation lag times were significantly longer than those before the intake. Furthermore, lipid peroxide formation and the electrophoretic mobility of LDL decreased markedly. These results suggested that perilla, especially the red variety, had high antioxidant activity and prevented the oxidation of LDL, which is a process strongly related to the development of atherosclerosis.

Sweet potato (Ipomoea batatas L.) leaves suppressed oxidation of low density lipoprotein (LDL) in vitro and in human subjects.

Sweet potato (Ipomoea batatas L.) leaves are consumed as vegetables around the world, especially in Southeast Asia. The aim of this study was to investigate the inhibitory effect of sweet potato leaves on low-density lipoprotein oxidation in vitro and in human subjects. We compared the antioxidant activity of 8 kinds of sweet potato leaves. Every sweet potato leaf had high radical scavenging activity and prolonged a lag time for starting low-density lipoprotein oxidation in vitro. We found that sweet potato leaves contained abundant polyphenol compounds and the radical scavenging activity and prolongation rate of lag time were highly correlated with total polyphenol content. We also confirmed that thiobarbituric acid reactive substances production was increased in endothelial cell-mediated low-density lipoprotein oxidation, which was decreased by treatment with sweet potato leaves. We further measured the low-density lipoprotein oxidizability in 13 healthy volunteers after their intake of 18 g of "Suioh", raw sweet potato leaves. "Suioh" prolonged a lag time for starting low-density lipoprotein oxidation and decreased low-density lipoprotein mobility. These results suggest that sweet potato leaves have antioxidant activity leading to the suppression of low-density lipoprotein oxidation.

Inhibitory effects of balsamic vinegar on LDL oxidation and lipid accumulation in THP-1 macrophages.

Oxidized low-density lipoprotein (LDL) is believed to contribute to atherosclerosis in part by being taken up into macrophages via scavenger receptors, thus accounting for foam cells. Balsamic vinegar is made from grapes and generally consumed in the Mediterranean region. In this study, we investigated the preventive effects of balsamic vinegar on LDL oxidation and foam cell formation. Balsamic vinegar had stronger 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging abilities and higher polyphenol concentrations than rice vinegar. Balsamic vinegar dramatically inhibited LDL oxidation by azoradicals and endothelial cell-mediated oxidation in vitro. Further, we assessed the anti-oxidative effect against LDL after balsamic vinegar consumption in human subjects. Balsamic vinegar prolonged the LDL oxidation lag time and decreased lipid peroxide (LPO) and lyso-phosphatidylcholine (LPC) in LDL particles. We next examined the effect of balsamic vinegar on foam cell formation. Oil red O staining showed that balsamic vinegar inhibited oxidized LDL-induced foam cell formation in THP-1 macrophages. The concentrations of intracellular triglycerides and total cholesterols were reduced in the presence of balsamic vinegar. In addition, balsamic vinegar decreased the mRNA and protein expression level of scavenger receptors in THP-1 macrophages. These results showed that balsamic vinegar contained abundant polyphenols and inhibited LDL oxidation and oxidized LDL-induced foam cell formation by decreasing the expression of scavenger receptors.