中国人群副氧酶基因与冠心病发病的关系

目的 :探讨中国人群副氧酶基因与冠心病 (CHD)发病的关系。方法 :利用多聚酶链反应 -变性梯度凝胶电泳技术对中国 12 2例 CHD患者 (其中 49例并发 2型糖尿病 ) ,49例 2型糖尿病对照者和 10 1例正常对照者进行副氧酶全基因筛查。结果 :中国人群副氧酶基因存在 Gln- Arg1 91 多态性 ,A、B等位基因频率分别为 39%、6 1%。CHD组副氧酶基因 3种基因型 (AA、AB和 BB)分布与对照组差异无显著性意义 ,但 CHD并发 2型糖尿病患者的 B等位基因频率较 2型糖尿病和正常对照者显著增高 (79% :6 2 %和 6 1% ,均 P <0 .0 5 )。结论 :B等位基因是中国 2型糖尿病患者并发 CHD的危险因素之一     

The role of proprotein convertase subtilisin/kexin type-9 concentration and paraoxonase 1 activities in the blood of women with polycystic ovary syndrome

This study aimed to evaluate the concentration of proprotein convertase subtilisin/kexin type-9 (PCSK9) and the activities of paraoxonase 1 in women with and without polycystic ovary syndrome (PCOS). We found significant higher PCSK9, whereas lower high-density lipoprotein concentration in the serum of women with PCOS when compared to the group without PCOS. Also paraoxonase 1 activities were significantly different between women with PCOS than without PCOS. In addition, the women with PCOS and insulin resistance had higher concentrations of PCSK9 than women with PCOS and insulin sensitivity. Higher PCSK9 concentration in the group with PCOS could be also associated with hormones concentrations.Changes in paraoxonase 1 activities and lipid profile parameters as well as higher concentration of PCSK9 in the group of women with PCOS could be associated with metabolism disorders, but due to the small clinical sample size, the study should be continued.     

Quercetin and Ethanol Attenuate the Progression of Atherosclerotic Plaques With Concomitant Up Regulation of Paraoxonase1 (PON1) Gene Expression and PON1 Activity in LDLR−/− Mice

Background: As moderate wine drinking is atheroprotective, it is clinically relevant to elucidate its possible mechanism/s of action/s. Our objective is to demonstrate the potential benefits of the wine components, quercetin and ethanol, on the development of aortic plaques with parallel changes in antiatherogenic factors. Methods and Results: The effects of quercetin and ethanol on the development of aortic atherosclerotic lesions, liver PON1 gene expression, and serum PON1 activity were measured in LDLR^?/? mice on an atherogenic diet for 4 and 8 weeks. Depending on the duration and dosage of these modulators, 12.5 to 25 mg/dl quercetin (12.5Q to 25Q) and 18 to 25% ethanol, the magnitude of decreases in aortic lesions caused by moderate ethanol and quercetin ranged from 20 to 70% (p < 0.05 to p < 0.001) based on ultrasound biomicroscopy (UBM) analyses, and from 18 to 61% (p < 0.05 to p < 0.001) based on morphometric analyses. The composite plot of all the UBM and morphometric data showed significant correlation between these 2 methods (p = 0.0001, Pearson r = 0.79 for 4‐week treatment; p = 0.000004, Pearson r = 0.84 for 8‐week treatment). Concomitantly, 4‐week treatments with 12.5Q and 18% ethanol up regulated liver PON1 mRNA by 41% (p < 0.05) and 37% (p < 0.05), respectively, accompanied by 92% (p < 0.001) and 61% (p < 0.001) increases in serum PON1 activity, respectively. The corresponding values after 8‐week treatment with 12.5Q and 18% ethanol were 23% (p < 0.05) and 40% (p < 0.02) with respect to the up regulation of liver PON1 mRNA expression, while the stimulations of serum PON1 activity were 75% (p < 0.001) and 90% (p < 0.001), respectively. Conclusions: Based on these findings, we conclude that quercetin and moderate ethanol significantly inhibit the progression of atherosclerosis by up regulating the hepatic expression of the antiatherogenic gene, PON1, with concomitant increased serum PON1 activity.     

Hepatoprotective effect of the hydroalcoholic extract of Cichorium intybus in a rat model of obstructive cholestasis

Background and study aimsObstructive cholestasis increases the levels of oxidants and inflammatory mediators, leading to liver damage. Previous studies have found that Cichorium intybus possesses anti-inflammatory effects. In the present study, the effects of the hydroalcoholic extract of C. intybus leaves were assessed in a rat model of obstructive cholestasis.Material and methodsMale Wistar rats were randomly divided into five groups (n = 6 rats per group): sham-operated, control [bile duct ligation (BDL) + vehicle)] and BDL + extract treatment (100, 200 and 400 mg/kg/day, i.p.) groups. Rats received treatments for 7 consecutive days. On the eighth day, prothrombin time (PT); serum albumin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase and total and direct bilirubin levels and total antioxidant and paraoxonase activities were measured using colorimetric methods. In addition, tumour necrosis factor-α and nitric oxide (NO) levels were measured using enzyme-linked immunosorbent assay.ResultsThe hydroalcoholic extract of C. intybus significantly decreased PT and the serum levels of AST, ALT, TNF-α and NO compared with the control group (p < 0.05). On the other hand, the serum albumin levels were increased in the extract-treated groups compared with the control group (p < 0.05).ConclusionThe hydroalcoholic extract of C. intybus protects the liver against injury induced by obstructive cholestasis.     

Increased macrophage cholesterol biosynthesis and decreased cellular paraoxonase 2 (PON2) expression in Δ6-desaturase knockout (6-DS KO) mice: Beneficial effects of arachidonic acid

Objective

To analyze the possible role of arachidonic acid (AA) in macrophage cholesterol biosynthesis and in PON2 expression.

Methods and results

We used peritoneal macrophages (MPM) from the 6-DS KO mice that were fed a diet without or with AA. Macrophage cholesterol biosynthesis rate and HMGCoA-reductase mRNA levels were substantially increased, by 98% and 67%, respectively, in MPM from 6-DS KO vs. control (C57BL/6) mice. Furthermore, in the 6-DS KO vs. control mice MPM PON2 expression (mRNA and lactonase activity) was substantially decreased. In line with the above results, AA supplementation to 6-DS KO mice significantly decreased MPM cholesterol biosynthesis rate and HMGCoA-reductase mRNA levels, by 45% and by 4-fold respectively, and increased MPM PON2 lactonase activity and PON2 mRNA, by 119% and 2.3-fold, respectively.Similarly, incubation of control mice MPM or J774A.1 with AA, significantly and dose-dependently decreased cellular cholesterol biosynthesis rate, and increased PON2 expression. These effects were specific for AA since incubation of the cells with docosahexaenoic acid (DHA, another product of 6-DS) had no significant effects on cholesterol biosynthesis rate, and on PON2 activity.

Conclusions

AA decreased macrophage cholesterol biosynthesis rate, and increased PON2 expression. These effects could protect the cells from cholesterol accumulation and oxidation, and from foam cell formation, the hallmark of early atherogenesis.     

Betaine Protects Chronic Alcohol and ω‐3 PUFA‐Mediated Down‐Regulations of PON1 Gene,Serum PON1 and Homocysteine Thiolactonase Activities With Restoration of Liver GSH

Background: Paraoxonase (PON1) is an antioxidant enzyme that prevents LDL oxidation as well as detoxifies homocysteine thiolactone (HCTL), both of which can cause atherosclerosis. Chronic alcohol (ETOH) and high ω‐3 polyunsaturated fatty acids (ω‐3 PUFA) consumption may affect PON1 status presumably via reactive oxygen species by depleting liver glutathione (GSH), whereas betaine may counter their effects. Therefore, we investigated the influence of ETOH, ω‐3 PUFA, and betaine on liver GSH, PON1 expression, lipid score, as well as serum PON1 and HCTLase activities. Methods: Experimental rats belonging to various dietary groups were pair‐fed with Lieber‐DeCarli low (2.8% the dietary calories as ω3‐fatty acids) and high (13.8% the dietary calories as ω3‐fatty acids) menhaden fish alcohol‐liquid diets with and without betaine (10 g/l diet) for 8 weeks after which liver PON1 mRNA, GSH, lipid score, and serum PON1, HCTLase, and ALT activities were measured. Results: High ω‐3 PUFA decreased liver PON1 mRNA expression, serum PON1, and HCTLase activity by 23% (p < 0.01), 20% (p < 0.05), and 28% (p < 0.05), respectively compared to the low ω‐3 PUFA group. ETOH decreased PON1 mRNA expression by 25 and 30% (p < 0.01) with concomitant 27% (p < 0.05) and 38% (p < 0.01), decrease in liver GSH levels in low and high ω‐3 PUFA groups, respectively. Correspondingly, serum PON1 activity decreased by 23% (p < 0.05) and 58% (p < 0.01) while serum HCTLase activity decreased by 25% (p < 0.05) and 59% (p < 0.01) in the low and high ω‐3 PUFA ETOH groups, respectively. Betaine restored liver PON1 mRNA expressions in low and high ω‐3 PUFA ETOH groups with parallel restorations of PON1 activity and liver GSH. Concomitantly, betaine reduced hepatosteatosis accompanied by alleviation of liver injury caused by chronic alcohol and high ω‐3 PUFA. Conclusions: Based on these results, we conclude that dietary betaine not only atheroprotective by restoring liver GSH that quenches free radicals, but also may alleviate liver injury by reducing hepatosteatosis.     

Anti-ulcer Activity of Curcumin on Experimental Gastric Ulcer in Rats and Its Effect on Oxidative Stress/Antioxidant, IL-6 and Enzyme Activities

Objective To investigate the possible mechanism by which curcumio protects stomach during the acute chronic phase of gastric ulcer disease. Methods The rats were divided into four groups and fasted for 2 days with flee access to water. On the third day, the animals were fasted for a further 24 h with no access to water followed by surgery. Rats received different doses of curcumin （20, 40, and 80 mg/kg） or vehicle by oral gavage. Nineteen hours after ulcer induction, the rats were killed by decapitation. Stomach was opened along the greater curvature and ulcerative lesions were counted. Total juice acidity, neutrophils activity, mitochondrial activity, total antioxidants, paraoxonase （PON 1）/arylesterase and total peroxides were evaluated. DNA fragmentation （%） and pro-inflammatory cytokine IL-6 level were measured. The level of different gastro-cytoprotective effectors including total antioxidants and paraoxonase （PON 1）/arylesterase activities was measured. Results The anti-ulcer activity of curcumin was displayed by attenuating the different ulcerative effectors including gastric acid hyper-secretion, total peroxides, myeloperoxiase （MPO） activity, IL-6 and apoptotic incidence. Conclusion Cureumin appears to have a propitious protective effect against gastric ulcer development.     

Paraoxonase 1 gene promoter polymorphisms are associated with the extent of stenosis in coronary arteries

HDL-associated paraoxonase1 (PON1) is believed to be an important anti-oxidative enzyme in the retardation of atherosclerosis. In this study, we determined haplotypes of three SNPs within the PON1 gene promoter to elucidate association of functional sites with coronary artery disease (CAD). We applied a direct haplotyping procedure through ARMS (Amplification Refractory Mutation System) and RFLP (Restriction Fragment Length Polymorphism) analysis techniques. The haplotypes of the G(− 907)C, A(− 162)G and C(− 107)T polymorphisms within the 5' region of the PON1 gene were determined in 99 patients and 66 controls who were evaluated angiographically for the presence and extent of stenosis in coronary arteries. The genotype and haplotype distributions had significant differences between patient subgroups (One-, Two- and Three-vessel disease) but not between the patient and control groups. Multivariate analyses suggested decreased arylesterase activity is the most important independent factor in the CAD severity. The increase of high activity variants [G(− 907) and C(− 107)] within the two-allelic haplotypes was reversely associated with the extent of stenosis in coronary arteries. However, we could not determine the independent involvement each of the C(− 107)T and G(− 907)C polymorphisms on the extent of stenosis. We found no significant association between the A(− 162)G polymorphism and the extent of stenosis in vessels. The study indicated the association of polymorphic variations within the PON1 gene promoter haplotypes with the serum arlyesterase activity. The arlyesterase activity was also associated with the extent of stenosis in coronary arteries but not with primary development of atherosclerosis.     

PON1 status is influenced by oxidative stress and inflammation in coronary heart disease patients

Objectives

High-density lipoprotein (HDL) associated paraoxonase 1 (PON1) is an essential component of HDLs' capability to protect low-density lipoproteins (LDL) from oxidative modification and thus to limit the atherosclerotic process. The aim of the current study was to investigate the association between oxidative stress status, indices of inflammation and PON1 status parameters.

Design and methods

We determined the relationship between the oxidative stress status, inflammatory markers and PON1 status parameters in 261 middle-aged subjects: 156 coronary heart disease (CHD) patients and 105 CHD-free subjects (as the control group). The PON1 status involved PON1 activity measurements towards two substrates: paraoxon (POase activity) and diazoxon (DZOase activity) and subsequent PON1_Q192R activity phenotype determination.

Results

A statistically significant greater malondialdehyde (MDA) concentration in the RR phenotype subjects compared to QQ subjects within the CHD group was apparent (P < 0.05). Multiple linear regression analysis revealed an independent influence of plasmatic SOD activity (P < 0.05) on POase values and MDA (P < 0.01) and O₂⁻ (P < 0.05) on DZOase values. Involvement of inflammatory markers (fibrinogen and hsCRP) in the regression model did not hinder the influence of SOD and MDA on POase and DZOase activities, respectively.

Conclusions

Our CHD patients were in a state of oxidative stress, which was most evident in the RR phenotype group. The QQ phenotype group is associated with the lowest oxidative stress status level and also with a better capacity for anti-oxidative protection. Oxidative stress in CHD patients is maintained by systemic low-grade inflammation, which results in PON1 enzymatic activity exhaustion. Therefore, deeper investigation of an effective anti-oxidative and anti-inflammatory therapy should be necessary in order to increase anti-oxidative potency and improve PON1 status of CHD patients.