Wenhua Ling

Anthocyanin supplementation improves serum LDL- and HDL-cholesterol concentrations associated with the inhibition of cholesteryl ester transfer protein in dyslipidemic subjects

BACKGROUND Anthocyanins have been shown to exert benefits on the lipid profile in many animal models. Whether these molecules have similar beneficial effects in humans is currently unknown. OBJECTIVE The objective was to investigate the effects of berry-derived anthocyanin supplements on the serum lipid profile in dyslipidemic patients. DESIGN A total of 120 dyslipidemic subjects (age 40-65 y) were given 160 mg anthocyanins twice daily or placebo for 12 wk in a double-blind, randomized, placebo-controlled trial. RESULTS Anthocyanin consumption increased HDL-cholesterol concentrations (13.7% and 2.8% in the anthocyanin and placebo groups, respectively; P < 0.001) and decreased LDL-cholesterol concentrations (13.6% and -0.6% in the anthocyanin and placebo groups, respectively; P < 0.001). Cellular cholesterol efflux to serum increased more in the anthocyanin group than in the placebo group (20.0% and 0.2%, respectively; P < 0.001). Anthocyanin supplementation decreased the mass and activity of plasma cholesteryl ester transfer protein (CETP) (10.4% and 6.3%, respectively, in the anthocyanin group and -3.5% and 1.1%, respectively, in the placebo group; P < 0.001). In the anthocyanin group, the change in HDL cholesterol was negatively correlated with the change in CETP activity (r(s) = -0.330). The change in LDL cholesterol was positively correlated with the change in CETP mass (r(s) = 0.354). The change in cellular cholesterol efflux to serum was positively correlated with the change in HDL cholesterol (r(s) = 0.485). In vitro, cyanidin 3-O-beta-glucosides dose-dependently lowered CETP activity in human HepG2 cells. CONCLUSIONS Anthocyanin supplementation in humans improves LDL- and HDL-cholesterol concentrations and enhances cellular cholesterol efflux to serum. These benefits may be due to the inhibition of CETP.

Gut Microbiota Metabolism of Anthocyanin Promotes Reverse Cholesterol Transport in Mice Via Repressing miRNA-10b

Rationale: We and others have demonstrated that anthocyanins have antiatherogenic capability. Because intact anthocyanins are absorbed very poorly, the low level of circulating parent anthocyanins may not fully account for their beneficial effect. We found recently that protocatechuic acid (PCA), a metabolite of cyanidin-3 to 0-&bgr;-glucoside (Cy-3-G), has a remarkable antiatherogenic effect. Objective: To investigate whether mouse gut microbiota metabolizes Cy-3-G into PCA and to determine whether and how PCA contributes to the antiatherogenic potency of its precursor, Cy-3-G. Methods and Results: PCA was determined as a gut microbiota metabolite of Cy-3-G in ApoE−/− mice, verified by the utilization of antibiotics to eliminate gut microbiota and further microbiota acquisition. PCA but not Cy-3-G at physiologically reachable concentrations promoted cholesterol efflux from macrophages and macrophage ABCA1 and ABCG1 expression. By conducting a miRNA microarray screening, we revealed that expression of miRNA-10b in macrophages can be reduced by PCA. Functional analyses demonstrated that miRNA-10b directly represses ABCA1 and ABCG1 and negatively regulates cholesterol efflux from murine- and human-derived macrophages. Further in vitro and ex vivo analyses verified that PCA accelerates macrophage cholesterol efflux, correlating with the regulation of miRNA-10b-ABCA1/ABCG1 cascade, whereas Cy-3-G consumption promoted macrophage RCT and regressed atherosclerotic lesion in a gut microbiotaendependent manner. Conclusions: PCA, as the gut microbiota metabolite of Cy-3-G, exerts the antiatherogenic effect partially through this newly defined miRNA-10b-ABCA1/ABCG1-cholesterol efflux signaling cascade. Thus, gut microbiota is a potential novel target for atherosclerosis prevention and treatment.

Coffee consumption and risk of coronary heart diseases: a meta-analysis of 21 prospective cohort studies.

BACKGROUND A large amount of cohort studies addressed coffee consumption and risk of coronary heart disease (CHD) and yielded inconsistent results. We conducted a meta-analysis to estimate the pooling effects. METHODS We searched for all published English articles indexed in MEDLINE or PubMed from January 1966 to January 2008. Twenty-one independent prospective cohort studies, which tested CHD risk by coffee consumption, were identified. A general variance-based method was used to pool the relative risks (RR). 15,599 cases from 407,806 participants were included in pooling the overall effects. RESULTS As compared to the light coffee consumption (<1 cup/d in US or <or=2 cups/d in Europe), under the random-effects model, the pooled CHD RRs (95% CI) for all studies combined were 0.96 (0.87-1.06), 1.04 (0.92-1.17) and 1.07 (0.87-1.32) for the moderate (1-3 or 3-4 cups/d), heavy (4-5 or 5-6 cups/d) and very heavy (>or=6 or >or=7 cups/d) categories of coffee consumption (all p>0.05); Moderate coffee consumption showed significantly lower CHD RR (95% CI) of 0.82 (0.73-0.92) (p<0.001) in women, and of 0.87 (0.80-0.86) (p=0.001) in men and women followed <or=10 years. CONCLUSION Our findings do not support the hypothesis that coffee consumption increases the long-term risk of coronary heart disease. Habitual moderate coffee drinking was associated with a lower risk of CHD in women.

Cyanidin 3-glucoside attenuates obesity-associated insulin resistance and hepatic steatosis in high-fat diet-fed and db/db mice via the transcription factor FoxO1

Obesity is a major risk factor for the development of type 2 diabetes, and both conditions are now recognized to possess significant inflammatory components underlying their pathophysiologies. Here, we hypothesized that cyanidin 3-glucoside (C3G), a typical anthocyanin reported to possess potent anti-inflammatory properties, would ameliorate obesity-associated inflammation and metabolic disorders, such as insulin resistance and hepatic steatosis in mouse models of diabesity. Male C57BL/6J obese mice fed a high-fat diet for 12 weeks and genetically diabetic db/db mice at an age of 6 weeks received dietary C3G supplementation (0.2%) for 5 weeks. We found that dietary C3G lowered fasting glucose levels and markedly improved the insulin sensitivity in both high-fat diet fed and db/db mice as compared with unsupplemented controls. White adipose tissue messenger RNA levels and serum concentrations of inflammatory cytokines (tumor necrosis factor-α, interleukin-6, and monocyte chemoattractant protein-1) were reduced by C3G, as did macrophage infiltration in adipose tissue. Concomitantly, hepatic triglyceride content and steatosis were alleviated by C3G. Moreover, C3G treatment decreased c-Jun N-terminal kinase activation and promoted phosphorylation and nuclear exclusion of forkhead box O1 after refeeding. These findings clearly indicate that C3G has significant potency in antidiabetic effects by modulating the c-Jun N-terminal kinase/forkhead box O1 signaling pathway and the related inflammatory adipocytokines.

Purified Anthocyanin Supplementation Improves Endothelial Function via NO-cGMP Activation in Hypercholesterolemic Individuals

BACKGROUND Anthocyanins have been shown to improve endothelial function in animal models. However, whether these compounds have similar beneficial effects in humans is largely unknown. METHODS In a short-term crossover study, 12 hypercholesterolemic individuals were given oral anthocyanins (320 mg) isolated from berries or placebo. Brachial artery flow-mediated dilation (FMD) was assessed before and after the intervention. In a long-term intervention trial (12 weeks), 150 hypercholesterolemic individuals were given anthocyanins (320 mg/day, n = 75) or placebo (n = 75), after which we measured FMD, plasma cGMP, and other serum biomarkers. Another short-term intervention was conducted in the presence of NO-cGMP inhibitors in 6 people and in a rat aortic ring model (n = 8). RESULTS Significant increases of FMD from 8.3% (0.6%) at baseline to 11.0% (0.8%) at 1 h and 10.1% (0.9%) at 2 h were observed after short-term anthocyanin consumption, concomitantly with increases of plasma anthocyanin concentrations (P < 0.05). In the study participants who received long-term anthocyanin intervention, compared with the control group, we observed significant increases in the FMD (28.4% vs 2.2%), cGMP (12.6% vs -1.2%), and HDL-cholesterol concentrations, but decreases in the serum soluble vascular adhesion molecule-1 and LDL cholesterol concentrations (P < 0.05). The changes in the cGMP and HDL cholesterol concentrations positively correlated with FMD in the anthocyanin group (P < 0.05). In the presence of NO-cGMP inhibitors, the effects of anthocyanin on endothelial function were abolished in human participants and in a rat aortic ring model. CONCLUSIONS Anthocyanin supplementation improves endothelium-dependent vasodilation in hypercholesterolemic individuals. This effect involves activation of the NO-cGMP signaling pathway, improvements in the serum lipid profile, and decreased inflammation.

Anti-inflammatory effect of purified dietary anthocyanin in adults with hypercholesterolemia: a randomized controlled trial.

BACKGROUND AND AIM Atherosclerosis is a chronic inflammatory disease and previous studies have demonstrated that anthocyanin inhibits atherosclerosis. In the present study, we explored the effects of anthocyanins on inflammatory cytokines in hypercholesterolemic adults and cell lines. METHODS AND RESULTS A total of 150 subjects with hypercholesterolemia consumed a purified anthocyanin mixture (320 mg/d) or a placebo twice a day for 24 weeks in a randomized, double-blind trial. Anthocyanin consumption significantly decreased the levels of serum high sensitivity C-reactive protein (hsCRP) (-21.6% vs. -2.5%, P = 0.001), soluble vascular cell adhesion molecule-1 (sVCAM-1) (-12.3% vs. 0.4%, P = 0.005) and plasma IL-1β (-12.8% vs. -1.3%, P = 0.019) compared to the placebo. We also found a significant difference in the LDL-cholesterol (-10.4% vs. 0.3%, P = 0.030) and HDL-cholesterol level changes (14.0% vs. -0.9%, P = 0.036) between the two groups. In cell culture assays in vitro, purified anthocyanin mixture, delphinidin-3-Ο-β-glucoside (Dp-3g) and cyanidin-3-Ο-β-glucoside (Cy-3g) inhibited IL-6 and IL-1β-induced CRP production (P < 0.05) in HepG2 cell line and LPS-induced VCAM-1 secretion (P < 0.05) in porcine iliac artery endothelial cell line respectively in a dose-dependent manner. In addition, the reduction of inflammatory cytokines associated with anthocyanin mixture was stronger when compared with the effects of Dp-3g and Cy-3g separately (P < 0.05). CONCLUSIONS Anthocyanin mixture reduced the inflammatory response in hypercholesterolemic subjects. In addition, different anthocyanin compounds were found to have additive or synergistic effects in mediating anti-inflammatory responses in vitro cell culture assays.

Anthocyanins Induce Cholesterol Efflux from Mouse Peritoneal Macrophages THE ROLE OF THE PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR γ-LIVER X RECEPTOR α-ABCA1 PATHWAY

It is widely accepted that stimulation of reverse cholesterol transport, the efflux of excess cholesterol from peripheral tissues and transferring it to the liver for biliary excretion, is becoming an important component in reducing excess cholesterol deposition in atherosclerotic plaques. The ATP-binding cassette transporter has been identified as a key regulator of macrophage cholesterol efflux and apoAI-mediated reverse cholesterol transport. In vivo studies have documented anthocyanins, a large group of naturally phenolic compounds rich in plants, possess substantial capacities in improving plasma cholesterol levels. In this study, we investigated the potential role of anthocyanins in modulating cholesterol efflux from mouse peritoneal macrophages and macrophage-derived foam cells and the possible molecular mechanism linking ABCA1 to cholesterol efflux. Incubation of the mouse peritoneal macrophages and macrophage-derived foam cells with cyanidin-3-O-β-glucoside and peonidin-3-O-β-glucoside led to dose-dependent (1–100 μm) induction in cholesterol efflux and ABCA1 mRNA expression, and this effect could be blocked by the ABCA1 inhibitor 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid, disodium salt, and a general inhibitor of gene transcription actinomycin D. Treatment of the macrophages with anthocyanins also activated peroxisome proliferator-activated receptor γ, liver X receptor α mRNA expression, and their mediated gene expression. Addition of geranylgeranyl pyrophosphate ammonium salt or GW9662 markedly inhibited the anthocyanin-induced increase of ABCA1 gene expression and apoAI-mediated cholesterol efflux. These data demonstrated that anthocyanin induces cholesterol efflux from mouse peritoneal macrophages and macrophage-derived foam cells and that stimulation of cholesterol efflux by anthocyanin is mediated, at least in part, by peroxisome proliferator-activated receptor γ-liver X receptor α-ABCA1 signaling pathway activation.

Curcumin attenuates Nrf2 signaling defect, oxidative stress in muscle and glucose intolerance in high fat diet-fed mice

AIM To investigate the signaling mechanism of anti-oxidative action by curcumin and its impact on glucose disposal. METHODS Male C57BL/6J mice were fed with either a normal diet (n = 10) or a high fat diet (HFD) (n = 20) to induce obesity and insulin resistance. After 16 wk, 10 HFD-fed mice were further treated with daily curcumin oral gavage at the dose of 50 mg/kg body weight (BW) (HFD + curcumin group). After 15 d of the curcumin supplementation, an intraperitoneal glucose tolerance test was performed. Fasting blood samples were also collected for insulin and glucose measurements. Insulin-sensitive tissues, including muscle, adipose tissue and the liver, were isolated for the assessments of malondialdehyde (MDA), reactive oxygen species (ROS) and nuclear factor erythroid-2-related factor-2 (Nrf2) signaling. RESULTS We show here that in a HFD mouse model, short-term curcumin gavage attenuated glucose intolerance without affecting HFD-induced BW gain. Curcumin also attenuated HFD-induced elevations of MDA and ROS in the skeletal muscle, particularly in its mitochondrial fraction, but it had no such an effect in either adipose tissue or the liver of HFD-fed mice. Correspondingly, in skeletal muscle, the levels of total or nuclear content of Nrf2, as well as its downstream target, heme oxygenase-1, were reduced by HFD-feeding. Curcumin intervention dramatically reversed these defects in Nrf2 signaling. Further analysis of the relationship of oxidative stress with glucose level by a regression analysis showed a positive and significant correlation between the area under the curve of a glucose tolerance test with MDA levels either in muscle or muscular mitochondria. CONCLUSION These findings suggest that the short-term treatment of curcumin in HFD-fed mice effectively ameliorates muscular oxidative stress by activating Nrf2 function that is a novel mechanism for its effect in improving glucose intolerance.

Cyanidin 3-glucoside protects 3T3-L1 adipocytes against H2O2-or TNF-α-induced insulin resistance by inhibiting c-Jun NH2-terminal kinase activation

Anthocyanins are naturally occurring plant pigments and exhibit an array of pharmacological properties. Our previous study showed that black rice pigment extract rich in anthocyanin prevents and ameliorates high-fructose-induced insulin resistance in rats. In present study, cyanidin 3-glucoside (Cy-3-G), a typical anthocyanin most abundant in black rice was used to examine its protective effect on insulin sensitivity in 3T3-L1 adipocytes exposed to H(2)O(2) (generated by adding glucose oxidase to the medium) or tumor necrosis factor alpha (TNF-alpha). Twelve-hour exposure of 3T3-L1 adipocytes to H(2)O(2) or TNF-alpha resulted in the increase of c-Jun NH(2)-terminal kinase (JNK) activation and insulin receptor substrate 1 (IRS1) serine 307 phosphorylation, concomitantly with the decrease in insulin-stimulated IRS1 tyrosine phosphorylation and cellular glucose uptake. Blocking JNK expression using RNA interference efficiently prevented the H(2)O(2)- or TNF-alpha-induced defects in insulin action. Pretreatment of cells with Cy-3-G reduced the intracellular production of reactive oxygen species, the activation of JNK, and attenuated H(2)O(2)- or TNF-alpha-induced insulin resistance in a dose-dependent manner. In parallel, N-acetyl-cysteine, an antioxidant compound, did not exhibit an attenuation of TNF-alpha-induced insulin resistance. Taken together, these results indicated that Cy-3-G exerts a protective role against H(2)O(2)- or TNF-alpha-induced insulin resistance in 3T3-L1 adipocytes by inhibiting the JNK signal pathway.

Early C-reactive protein in the prediction of long-term outcomes after acute coronary syndromes: a meta-analysis of longitudinal studies

Objective To assess the overall effects by a meta-analysis. Data sources Electronic searches on PubMed and Ovid Medline from their start to October 2009 were carried out. Objective Cohort studies and secondary analysis of randomised controlled trials reporting the relative risk (RR) of recurrent cardiovascular events or death associated with C-reactive protein (CRP) obtained within 72 h from acute coronary syndromes (ACS) onset. Data extraction Two epidemiologists independently abstracted information on study design, study and participant characteristics, level of CRP, outcomes, control for potential confounding factors and risk estimates using a standardised form. Results A general variance-based method was used to pool the estimates of risk. Thirteen studies containing 1364 new cases identified from 9787 patients during the follow-up periods reported the risk estimates by CRP categories. Compared with the bottom CRP category (≤3 mg/l), the pooled RRs and their 95% CIs were 1.40 (1.18 to 1.67) for the middle (3.1∼10 mg/l) category and 2.18 (1.77 to 2.68) for the top (>10 mg/l) category of CRP values with a random-effects model, respectively. Another four and three studies reported the risk by unit of CRP or logarithmically transformed CRP. The pooled RRs (95% CI) were 1.49 (1.06 to 2.08) per 5 mg/l and 1.26 (0.95 to 1.69) per natural logarithm of CRP (mg/l), respectively. Conclusions Greater early blood CRP moderately increases long-term risk of recurrent cardiovascular events or death, and may be a valuable prognostic predictor in patients after ACS.