Xiang Feng

Sun Yat-Sen University, Shengcheng, Guangdong, China

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Publications (15)35.29 Total impact

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    ABSTRACT: The exact mechanism of the protective role of Resveratrol (Res) in lipid metabolism and oxidative stress is not well elucidated. The present study aimed to investigate the potential benefits and possible mechanisms of Res on the amelioration of oxidative stress and hepatic steatosis in a KKAy mouse model.
    Nutrition & metabolism. 01/2014; 11:35.
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    ABSTRACT: Not only is iron deficiency an abnormal iron status, but iron overload is also harmful for human health. It has been reported that overloaded iron stores are positively associated with increased coronary artery disease (CAD) risk, which is called the "iron-heart hypothesis". Previous studies evaluating the relationships between fatty acids (FAs) and body iron status only focused on participants with iron deficiency. However, whether FA composition is related to overloaded iron remains unclear. Therefore, this study was designed to investigate the relationships between erythrocyte membrane FA (Ery-FA) composition and overloaded body iron status as measured by plasma ferritin levels in Chinese CAD patients. A total of 446 subjects with angiographically identified CAD (mean age 63.1 years, 76.9% males) were recruited in a hospital between 2009 and 2010. Ery-FAs were measured by gas chromatography and the activities of FA desaturases, which are involved in the de novo synthesis of unsaturated FAs, were evaluated by using FA product-to-precursor ratios. Results showed that the average iron status was a bit overloaded in the population (median ferritin levels of 234.1 ng mL(-1) and 40.4% males of overload). Moreover, in males, saturated FAs (SFAs) were positively correlated (22 : 0, r = 0.182, p = 0.001; 24 : 0, r = 0.214, p < 0.001), whereas monounsaturated FAs (MUFAs) and n-6 polyunsaturated FAs (PUFAs) were negatively correlated (18 : 1n-9, r = -0.120, p = 0.028; 18 : 2n-6, r = -0.216, p < 0.001) with plasma ferritin levels. A negative correlation (r < 0, p < 0.05) between stearoyl-CoA desaturase (SCD) activity and ferritin levels was also found in males. However, all the significant associations above were not observed in females. In conclusion, the Ery-FA composition was related to overloaded plasma ferritin levels only in Chinese males with angiographic CAD, which might be linked to the change of SCD activity. The results may contribute to the understanding of the mechanism of the iron-heart hypothesis.
    Food & function. 09/2013;
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    ABSTRACT: OBJECTIVE: To compare the effect of vegetarian diets and omnivorous diets on triacylglycerols (TGs). METHODS: We identified cross-sectional and cohort studies related to TGs (an index of blood lipids) listed on PubMed and ISI Web of Knowledge, bibliographies, and related references and studies suggested by search engines to further increase the range of data collected (all-year time span until May 2011). RESULTS: Twelve studies with 1300 subjects were included for meta-analysis. Vegetarian diets were effective in lowering plasma TG concentrations (standardized mean difference -1.28 mmol/L, 95% confidence interval -2.14 to -0.42); in eight developed countries, plasma TG levels were insignificantly lower in vegetarians than in omnivores (standardized mean difference -0.31 mmol/L, 95% confidence interval -1.13 to 0.50), but in four developing countries, the phenomenon was obvious (standardized mean difference -4.06 mmol/L, 95% confidence interval -7.43 to -0.70). CONCLUSION: Compared with omnivorous diets, vegetarian diets provide health benefits, especially in developing countries. This favorable effect occurs even if vegetarian diets last for at least 6 mo.
    Nutrition 12/2012; · 2.86 Impact Factor
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    ABSTRACT: Lipoprotein (a) (Lp [a]) is known being correlated with coronary artery disease (CAD). The SLC22A3-LPAL2-LPA gene cluster, relating with modulating the level of plasma Lp (a), has recently been reported to be associated with CAD in Caucasians. The purpose of this study was to verify whether this finding can be expanded to the Chinese Han population. Using a Chinese Han sample, which consisted of 1012 well-characterized CAD patients and 889 healthy controls, we tested the associations of four SNPs (rs2048327, rs3127599, rs7767084 and rs10755578) in the SLC22A3-LPAL2-LPA gene cluster, and their inferred haplotypes with the risk of CAD. Allelic, genotypic and haplotype association analyses all showed that the gene cluster was not associated with CAD in this Chinese Han sample. We for the first time explored the association of the four SNPs in the SLC22A3-LPAL2-LPA gene cluster with CAD in a large Chinese Han sample. Nevertheless, this study did not reveal any significant evidence of this gene cluster to increase the risk of CAD in this population.
    Lipids in Health and Disease 10/2012; 11:128. · 2.31 Impact Factor
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    ABSTRACT: The aim of the present study was to explore risk variants for coronary artery disease (CAD) and to evaluate their joint effects (quantified by genetic risk score; GRS) on the discrimination of CAD in a Chinese Han sample. An association analysis of 91 single nucleotide polymorphisms (SNPs) with CAD risk was undertaken in 1,007 CAD patients and 889 healthy controls. Two GRSs, counted GRS (cGRS) and weighted GRS (wGRS), were calculated using the significant SNPs, and their discriminant power for CAD was assessed using receiver-operating characteristic (ROC) curve analysis. Eight SNPs (rs11206510, rs10118757, rs2383206, rs501120, rs2075292, rs174547, rs173539, and rs255052) were nominally significantly associated with CAD (P<0.05), and 5 of them were newly reported. The GRSs derived from the 8 SNPs improved the discrimination of CAD compared to that using 4 conventional risk factors (P=0.002 for cGRS and P=0.009 for wGRS). After 10-fold cross-validation 100 times, the average areas under the curve were 0.668 (95% confidence interval [CI]: 0.667-0.669), 0.686 (95% CI: 0.685-0.687) and 0.690 (95% CI: 0.689-0.691) for models with conventional risk factors only, conventional risk factors plus cGRS, and conventional risk factors plus wGRS, respectively. A multigenic GRS, generated by combining multiple gene variants, can improve discrimination of CAD, thereby confirming the joint effects of these gene variants on CAD in this Chinese Han population.
    Circulation Journal 05/2012; 76(8):1987-92. · 3.58 Impact Factor
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    ABSTRACT: Resveratrol (Res) has attracted great interest regarding its effects related to metabolic syndrome, especially for lipid metabolic disorder or insulin resistance; however, the underlying mechanisms remain elusive. To explore the effects of Res on insulin sensitivity and the underlying mechanism, insulin-resistant KKA(y) mice were treated with 2 and 4 g/kg diets of Res for 12 weeks. After the treatment, blood glucose, serum insulin, glucose tolerance, and insulin tolerance, as well as other indices such as adiponectin mRNA in epididymal adipose tissues, silent information regulator 1 (Sirt1), AMP-activated protein kinase (AMPK), insulin receptor substrate 1 (IRS1), and phosphorylated protein kinase B (PKB/AKT) proteins in liver and soleus muscles, were investigated. The results indicate that Res intervention reduces blood glucose and serum insulin levels, improves insulin and glucose tolerance, increases serum adiponectin and adiponectin mRNA levels in epididymal adipose tissues, and more importantly, elevates Sirt1, p-AMPK, p-IRS1, and p-AKT levels in liver and soleus muscles. In conclusion, Res could improve insulin sensitivity and ameliorate insulin resistance in KKA(y) mice, which may be associated with the upregulation of Sirt1 protein in liver and soleus muscles and consequent AMPK activation, as well as insulin-signaling related proteins.
    Canadian Journal of Physiology and Pharmacology 02/2012; 90(2):237-42. · 1.56 Impact Factor
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    ABSTRACT: Resveratrol is a natural polyphenolic compound with anti-inflammatory, antioxidant, and neuroprotective properties, and it serves as a chemopreventive and chemotherapeutic agent. However, only very limited data have been obtained regarding the effects of resveratrol on pre-adipocytes and the mechanisms of these effects remain largely unknown. In this study, murine 3T3-L1 pre-adipocytes were incubated with resveratrol and cell apoptosis was investigated. Resveratrol caused S-phase arrest to inhibit cell proliferation and significantly increased the LDH leaking ratio. Hoechst 33258 staining and transmission electron microscopy revealed the ultrastructural changes in nuclear chromatins of apoptotic cells. Furthermore, resveratrol activated the mitochondrial signaling with the decreases in the mitochondrial membrane potential (MMP), cytochrome C release and the activations of caspase 9 and caspase 3. Resveratrol treatment also increased the protein level of Sirt1. By using small interfering RNAs of Sirt1, AMP-activated protein kinase α (AMPKα), Survivin, and the AMPK agonist (AICAR) and specific inhibitors for protein kinase B (AKT) or caspases, it was demonstrated that activation of Sirt1 inhibited AKT activation and further decreased the expression of survivin. It could also increase AMPK activation. Both signaling pathways activated mitochondrion-mediated pathway. Our findings clarified the apoptotic effects of resveratrol in 3T3-L1 pre-adipocytes and revealed the involved pathway including AMPK, AKT, and survivin, suggesting its potential therapeutic application in the treatment or prevention of obesity and related metabolic symptoms.
    The Journal of nutritional biochemistry 11/2011; · 4.29 Impact Factor
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    ABSTRACT: Hepatocytes show endoplasmic reticulum (ER) stress when exposed to lipotoxic stimuli such as hyperlipidemia. Recent work has revealed that adenosine monophosphate activated protein kinase (AMPK) can mitigate ER stress. In this study, we investigated the impact of AMPK on lipid-induced ER stress in hepatocytes and its underlying molecular mechanism. Treatment with 5-aminoimidazole-4- carboxamide ribonucleotide (AICAR), an AMPK agonist, or overexpression of a constitutively active AMPK (CA-AMPK) significantly suppressed lipid-mediated ER stress, leading to marked protection against lipotoxic death. Incubation with AICAR and CA-AMPK overexpression induced the expression of an ER-associated chaperone, 150-kDa oxygen-regulated protein (ORP150), at both the mRNA and protein levels in hepatocytes. Forkhead box O1 (FOXO1) was identified as the critical transcription factor regulating ORP150 expression because silencing FOXO1 expression prevented the induction of ORP150 expression by AMPK. In contrast, overexpression of FOXO1-ADA promoted ORP150 expression in hepatocytes. FOXO1 bound directly to the ORP150 promoter, which was enhanced upon in the presence of AICAR. AMPK acts to activate FOXO1 by increasing its deacetylation and transcriptional activity via silent mating type information regulation 2 homolog 1 (SIRT1). Furthermore, AICAR infusion enhanced ORP150 expression, resulting in the marked amelioration of hepatic ER stress and apoptosis in C57BL/6J mice fed a high-fat diet. Our results reveal a novel mechanism by which AMPK regulates ER homeostasis in hepatocytes and suggest that AMPK has a protective role against hypercholesterolemia-related liver damage.
    Journal of Biological Chemistry 02/2011; · 4.65 Impact Factor
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    ABSTRACT: Hepatocytes show endoplasmic reticulum (ER) stress when exposed to lipotoxic stimuli such as hyperlipidemia. Recent work has revealed that AMP- activated protein kinase (AMPK) can mitigate ER stress. In this study we investigated the impact of AMPK on lipid-induced ER stress in hepatocytes and its underlying molecular mechanism. Treatment with 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), an AMPK agonist, or overexpression of a constitutively active AMPK significantly suppressed lipid-mediated ER stress, leading to marked protection against lipotoxic death. Incubation with AICAR and constitutively active AMPK overexpression induced the expression of an ER-associated chaperone, 150-kDa oxygen-regulated protein (ORP150), at both the mRNA and protein levels in hepatocytes. Forkhead box O1 (FOXO1) was identified as the critical transcription factor regulating ORP150 expression because silencing FOXO1 expression prevented the induction of ORP150 expression by AMPK. In contrast, overexpression of FOXO1-ADA promoted ORP150 expression in hepatocytes. FOXO1 bound directly to the ORP150 promoter, which was enhanced in the presence of AICAR. AMPK acts to activate FOXO1 by increasing its deacetylation and transcriptional activity via silent mating type information regulation 2 homolog 1 (SIRT1). Furthermore, AICAR infusion enhanced ORP150 expression, resulting in the marked amelioration of hepatic ER stress and apoptosis in C57BL/6J mice fed a high fat diet. Our results reveal a novel mechanism by which AMPK regulates ER homeostasis in hepatocytes and suggest that AMPK has a protective role against hypercholesterolemia-related liver damage.
    Journal of Biological Chemistry 02/2011; 286(13):11119-31. · 4.65 Impact Factor
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    ABSTRACT: Mitochondrial acyl-CoA:glycerol-sn-3-phosphate acyltransferase 1 (mtGPAT1) controls the first step of triacylglycerol (TAG) synthesis and is critical to the understanding of chronic metabolic disorders such as primary nonalcoholic fatty liver disease (NAFLD). Anthocyanin, a large group of polyphenols, was negatively correlated with hepatic lipid accumulation, but its impact on mtGPAT1 activity and NAFLD has yet to be determined. Hepatoma cell lines and KKAy mice were used to investigate the impact of anthocyanin on high glucose-induced mtGPAT1 activation and hepatic steatosis. Treatment with anthocyanin cyanidin-3-O-β-glucoside (Cy-3-g) reduced high glucose-induced GPAT1 activity through the prevention of mtGPAT1 translocation from the endoplasmic reticulum to the outer mitochondrial membrane (OMM), thereby suppressing intracellular de novo lipid synthesis. Cy-3-g treatment also increased protein kinase C ζ phosphorylation and membrane translocation in order to phosphorylate the mtF0F1-ATPase β-subunit, reducing its enzymatic activity and thus inhibiting mtGPAT1 activation. In vivo studies further showed that Cy-3-g treatment significantly decreases hepatic mtGPAT1 activity and its presence in OMM isolated from livers, thus ameliorating hepatic steatosis in diabetic KKAy mice. Our findings reveal a novel mechanism by which anthocyanin regulates lipogenesis and thereby inhibits hepatic steatosis, suggesting its potential therapeutic application in diabetes and related steatotic liver diseases.
    The Journal of Lipid Research 02/2011; 52(5):908-22. · 4.39 Impact Factor
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    ABSTRACT: To investigate the relationship among dietary iron intake, body iron overload and risk of metabolic syndrome. 87 MS patients and 102 matched healthy adults were recruited. Fasting blood samples were collected and assayed for serum ferritin (SF), serum iron (SI), total iron-binding capacity (TIBC), fasting insulin (FIN), fasting blood glucose (FBG), MDA, SOD and NF-kappaB. The data of dietary intake were collected by using a 24-hour dietary recall method for 7 consecutive days by trained interviewers. Total dietary iron intake, iron intake from animal source, serum MDA and NF-kappaB in MS group was significantly higher than that in the control group. SF, SI, siderophilin saturation and serum SOD in MS group was lower than that in the control group. There is a positive correlation between serum iron and insulin resistance index and blood glucose. When the total dietary iron intake greater than 15 mg/d was defined as iron over intake, the risk of suffering from MS was high (OR = 7.12) in those subjects with over intake of total iron. When the animal source iron intake greater than 7.5 mg/d was defined as iron over intake, the risk of suffering from MS was high (OR = 7.73) in those subjects with over intake of animal source iron. Fat and iron intake are influencing factors for MS according to Logistic multiple factor regression analysis. Iron overload induced by higher meat-based iron intake might be associated with higher risk of MS.
    Wei sheng yan jiu = Journal of hygiene research 01/2011; 40(1):32-5.
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    ABSTRACT: Increasing evidence suggests that adenosine monophosphate-activated protein kinase (AMPK) exerts protective effects for cardiovascular diseases apart from the regulation of energy homeostasis. However, the role of AMPK and its underlying mechanism on macrophage foam cell formation are poorly understood. In this study, we sought to investigate the potential effects of AMPK in modulating cholesterol deposition by using murine macrophage-derived foam cells. Incubation with 5-aminoimidazole-4-carboxyamide ribonucleoside (AICAR) markedly attenuated the cholesterol ester accumulation in oxidized low density lipoprotein-loaded macrophages. Notably, AICAR treatment significantly increased ATP-binding cassette transporters G1 (Abcg1) mRNA and protein levels without affecting mRNA and protein expression of ABCA1, scavenger receptors, including scavenger receptor-A, CD36, and scavenger receptor-BI (SR-BI), and cholesterol synthesis-related genes. The up-regulation of Abcg1 by AICAR was independent of the liver X receptor/retinoid X receptor pathway but dependent on ERK activation. AICAR elevates Abcg1 expression through a post-transcriptional mechanism that stabilizes the mRNA. Using a heterologous system with luciferase as a reporter, we further identify the Abcg1 mRNA 3'-UTR responsible for the regulatory effect of AICAR. Prevention of ABCG1 expression by small interfering RNA abolished the AICAR-mediated attenuation on foam cell formation. Furthermore, increased ABCG1 expression and reduced lipid accumulation were demonstrated in AICAR-treated macrophages isolated from apolipoprotein E-deficient mice (apoE(-/-) mice). AICAR treatment also inhibited atherosclerotic plaque formation in apoE(-/-) mice. Our findings elucidate a precise mechanism involved in the prevention of atherogenesis by AMPK.
    Journal of Biological Chemistry 10/2010; 285(43):33499-509. · 4.65 Impact Factor
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    ABSTRACT: To study the effect of n-3 polyunsaturated fatty acids (EPA, DHA) on the production of NO, expression of iNOS mRNA and DNA-binding activity of NFkappaB in human monocyte. RT-PCR and enzyme reduction method were used to measure the expression of iNOS mRNA and production of NO respectively. The DNA-binding activity of NFkappaB was assessed by EMSA. EPA, DHA can decrease the production of NO, expression of iNOS mRNA and DNA-binding activity of NFkappaB between the dosage of 10microg/ml and 20microg/ml in human peripheral blood monocyte in vitro. EPA, DHA have inhibitory effects on NO production, iNOS mRNA expression and DNA-binding activity of NFkappaB in monocyte. It indicates EPA, DHA suppress the production of inflammatory mediators via the NFkappaB signal transduction pathways in human monocyte, accordingly suppress inflammatory responses.
    Wei sheng yan jiu = Journal of hygiene research 08/2007; 36(4):445-8.
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    ABSTRACT: This study was designed to evaluate the effect of an anthocyanin-rich extract from black rice on hyperlipidemia and insulin resistance in fructose-fed rats. Rats fed fructose diet for 4 weeks exhibited significantly higher plasma insulin levels and lower insulin sensitivity than the control rats fed AIN-93G diet. Dietary supplementation with the anthocyanin-rich extract (5 g/kg of high-fructose diet) prevented the development of fructose-induced insulin resistance. After fructose-induced insulin resistance had been established, 4-week treatment with the anthocyanin-rich extract (5 g/kg of high-fructose diet) or pioglitazone (270 mg/kg of high-fructose diet) ameliorated the glucose intolerance and hyperlipidemia, but the extract failed to reverse the fructose-induced hyperinsulinemia as pioglitazone did. In addition, rats supplemented by the extract exhibited lower oxidative stress than the fructose-fed controls, as indicated by the lower concentrations of plasma thiobarbituric acid reactive substances and blood oxidized glutathione. Overall, these results suggest that the anthocyanin-rich extract from black rice improves certain metabolic abnormalities associated with diets high in fructose.
    Plant Foods for Human Nutrition 04/2007; 62(1):1-6. · 2.36 Impact Factor
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    ABSTRACT: To investigate the characteristics of calcium metabolism in relation to different levels of dietary calcium intakes in premenarche Chinese girls. Forty-nine healthy premenarche girls of Han ethic (9 - 11.5 years) were recruited, and divided into four groups respectively, receiving four different doses of calcium intakes for 6 days, 600 mg (usual diet), 900 mg (containing 250 ml of milk), 1200 mg (containing 250ml of milk and 750 mg of calcium carbonate) and 1500mg calcium (250 ml of milk and 1500 mg of calcium carbonate) per day. A 3-day urine and stool, and a 3-d duplicated food samples were collected to assess the calcium excretion in urine and feces and input of the dietary calcium during the treatment period. There were no significant differences in appearance calcium absorption among the four groups (55%, 53%, 52% and 52%). Urine calcium is correlated negatively with dietary protein and dietary phosphorus. And no correlation was found between dietary protein and calcium absorption. The appearance calcium absorption was (53 +/- 0.12) % in Chinese premenarche girls with dietary calcium intakes ranged between 800 to 1600 mg/d, high dietary protein intakes increase urine calcium secrete.
    Wei sheng yan jiu = Journal of hygiene research 08/2005; 34(4):445-8.