Do PON1-Q192R and PON1-L55M polymorphisms modify the effects of hypoxic training on paraoxonase and arylesterase activity?

Background:Low levels of antioxidant paraoxonase 1(PON 1)enzyme activity,PON1-Q192R polymorphism(a glutamine(Q)to arginine(R)substitution at position 192),PON1-L55M polymorphism(a leucine(L)to methionine(M)substitution at position 55),and oxidized low-density lipoprotein(oxLDL)are risk factors for coronary heart disease.Aerobic exercise improves PON1 activity,but the effects of hypoxic exercise are yet unclear.The aim of this study was to determine the effects of hypoxic underwater rugby training on PON1 activity and oxLDL levels and the role of the mentioned polymorphisms.Methods:Serum PON1 and arylesterase activities(ARE),PON1,PON3,and oxLDL protein levels(by using the enzyme-linked immunosorbent assays)were determined in an athletic group(42 trained male underwater rugby players;age=21.7±4.2 years,mean±SD)and a control group(43 sedentary men;age=23.9±3.2 years).The polymorphisms were determined from genomic DNA samples.Results:PON1 activity(25.1%,p=0.052),PON3(p<0.001),and oxLDL(p<0.001)of the athletic group,including most genotype groups,were higher than those of the control group.In comparison to the controls,PON1 activity levels(p=0.005)of the PON1-Q192R homozygote QQ genotype group and PON1 activity levels(30%,p=0.116)of the PON1-L55M homozygote LL genotype group were higher,whereas ARE activity values of athletic R allele carrier(Rc=QR+RR)(p=0.005)and LL group(p=0.002)were lower than the control genotype groups related to their polymorphisms.Conclusion:Hypoxic training can cause(1)significant oxidative stress,including oxLDL,and an antioxidant response(increase in PON1 activity and PON3),(2)differences in the activity of PON1 and ARE,which are modified by PON1-Q192R and PON1-L55M polymorphisms,respectively,and(3)improvements in PON1 activity of QQ and LL groups.However,hypoxic training can cause a disadvantage of LL and Rc groups for ARE.

Total oxidative stress, paraoxonase and arylesterase levels at patients with pseudoexfoliation syndrome and pseudoexfoliative glaucoma

AIMTo investigate the oxidative stress status of the aqueous humor and serum of patients with pseudoexfoliation (PEX) syndrome and pseudoexfoliative glaucoma (PEG) and to measure paraoxonase (PON) and arylesterase (ARE) levels.METHODSA total of 78 patients were enrolled in the study, with 26 patients in each separate group. The patients were divided into three groups: the first group entailed PEX syndrome patients, while the second group consisted of patients with PEG and the third group involved patients with no additional systemic diseases, other than the diagnosis of cataract as control. Total oxidative stress (TOS), total antioxidant capacity (TAC), PON, and ARE levels in aqueous humor and serum were measured.RESULTSTAC, PON and arylesterase levels in aqueous humor and serum of the PEX syndrome and PEG patients were significantly decreased compared with control group (P&#x0003c;0.05). TOS values were higher in patients with PEX syndrome and PEG than controls (P&#x0003c;0.05). TAC, PON and ARE levels of aqueous humor did not differ significantly between the PEX syndrome and PEG groupsCONCLUSIONThese findings are potentially of significance and add to the growing body of evidence for oxidative stress in PEX syndrome and PEG. Decreased antioxidant defense and increased oxidative stress system may play an important role in the pathogenesis of PEX syndrome and PEG.

Serum arylesterase and paraoxonase activity in patients with chronic hepatitis

AIM: To investigate the relationship between serum paraoxonase (PON1), AST, ALT, GGT, and arylesterase (AE) activity alterations and the degree of liver damage in patients with chronic hepatitis.METHODS: We studied 34 chronic hepatitis patients and 32 control subjects, aged between 35 and 65 years,in the Department of Infection and Clinical Microbiology at the Firat University School of Medicine. Blood samples were collected from subjects between 8:00 and 10:00 a.m. following a 12-h fast. Baseline and salt-stimulated PON1 activities were measured by the hydrolysis of paraoxon. Phenyl acetate was used as the substrate and formed phenol was measured spectrophotometrically at 270 nm after the addition of a 10-fold diluted serum sample in AE activity measurements.RESULTS: The results of this investigation revealed that the levels of AE activity decreased from 132±52 to 94±36 (29%), baseline PON1 activity from 452±112 to 164±67 (64%), salt-stimulated PON1 activity from 746±394 to 294±220 (61%), HDL from 58.4±5.1 to 47.2±5.6(20%), triglyceride from 133±51.2 to 86±34.0 (35%),while a slight increase in the level of LDL (from 163±54.1 to 177.3±56.0; 9%) and significant increases in the levels of AST (from 29±9.3 to 98±44), ALP (from 57.2±13.1 to 91±38.1), ALT (from 27.9±3.32 to 89±19.1), GGT (from 24.3±2.10 to 94±48.2), total bilirubin (from 0.74±0.02 to 1.36±0.06; 84%) and direct bilirubin (from 0.18±0.01 to 0.42±0.04; 133%) were detected.However, the levels of albumin, total protein, cholesterol,and uric acid were almost the same in chronic hepatitis and the control subjects.CONCLUSION: Low PON1 and AE activity may contribute to the increased liver dysfunction in chronic hepatitis patients by reducing the ability of HDL to retard LDL oxidation and might be clinically useful for monitoring the disease of chronic hepatitis.

对氧磷酶(Paraoxonase)的测定方法与临床意义

对氧磷酶 (Paraoxonase)是结合在高密度脂蛋白 (HDL)上的一种有机磷三酯化合物水解酶。最近研究表明 ,对氧磷酶可以保护低密度脂蛋白 (LDL)的氧化 ,其活性与基因多态性被认为是动脉粥样硬化、冠心病的独立危险因素。本文综述Paraoxonase的生化特征、基因的多态性。

Paraoxonase-1介导硫化氢的抗甲醛神经毒性作用(英文)

我们以往的研究工作证实了硫化氢(hydrogen sulfide,H2S)对甲醛神经毒性和氧化应激具有拮抗作用.Paraoxonase-1(PON-1)是机体重要的内源性抗氧化剂.本研究的目的是探讨PON-1是否可介导H2S的抗甲醛神经毒性作用.采用甲醛损伤PC12细胞为甲醛神经毒性的细胞模型.硫氢化钠(NaHS,一种H2S的供体)不仅可以上调PC12细胞PON-1的活力,还可恢复甲醛对PC12细胞PON-1表达与活力的抑制作用.2-hydroxyquinoline(2-HQ)是一种选择性PON-1抑制剂,它可显著降低H2S对甲醛细胞毒性、凋亡和活性氧(reactive oxygen species,ROS)累积的抑制作用.而且,2-HQ可阻止H2S逆转甲醛激活PC12细胞caspase-3和下调PC12细胞bcl-2表达.结果提示H2S依赖PON-1去保护PC12细胞对抗甲醛的神经毒性.我们的这一发现表明PON-1有希望成为防治甲醛神经损伤的新靶点.

Decreased paraoxonase1 activity and increased malondialdehyde and oxidative DNA damage levels in primary open angle glaucoma

To investigate the malondialdehyde（MDA） levels,paraoxonase1（PON1） activity and 8-hydroxy 2-deoxyguanosine（8-OHd G） levels in the primary open angle glaucoma（POAG） patient.Blood samples from 52 healthy individuals and 53 patients with POAG were analyzed for MDA and 8-OHd G by high-performance liquid chromatography（HPLC） and PON1 by spectrophotometry.The data obtained were analyzed statistically.MDA levels were 10.46±8.4 and 4.70±1.79 μmol; PON1 levels were 121 ±39.55 and 161.62 ±60.22 U/m L; and 8-OHd G values were1.32 ±0.53/10~6 d G and 0.47 ±0.27/10~6 d G in the POAG patients and the control group,respectively.The difference was significant in MDA levels,8-OHd G levels and PON1 activity in POAG patients in comparison with controls（P 〈0.001）.We concluded that the observed increase in MDA and 8-OHd G levels may be correlated with decreased PON1 activity.Oxidative stress plays an important role in glaucoma development.

Monitoring the level of serum paraoxonase 1 activity in liver transplantation patients

BACKGROUND: Paraoxonase 1(PON1) is an ester hydro- lase in serum and in the liver. Studies have suggested that PON1 measurement to the current battery of tests may im- prove the evaluation of chronic liver diseases. The aim of this study was to investigate the clinical significance of mo- nitoring the level of serum PON1 activity in liver transplan- tation patients. METHODS: A series of biochemical indexes were moni- tored in preoperative, operative and postoperative serum samples of 17 liver-transplanted patients. The change of se- rum PON1 level and its relations with other biochemical in- dexes were analyzed. RESULTS: PON1 was distributed normally in the healthy population and its reference value ranged from 45.5 to 265.8 U/mL. The PON1 level of all patients was lower than that of control group significantly (P<0.001); the level be- gan to elevate continuously 5 minutes after opening of the portal vein and was higher than that 90 minutes after open- ing of the portal vein ( P <0.05). Two days after operation it was still higher than the normal. The levels of serum ALT and AST elevated more significantly after opening of the portal vein than before operation and they were higher than the normal values till 2 days after the operation. CONCLUSIONS: The level of PON1 in serum may be taken as one of the effective indexes to assess whether the implant is alive and to monitor liver function of the patient together with other tests.

Paraoxonase 1 gene (Gln¹⁹²-Arg) polymorphism and the risk of coronary artery disease in type 2 diabetes mellitus

Background: Paraoxonase 1 (PON1) is reported to have an antioxidant and cardioprotective properties. Recently, an association of glutamine (Gln) or (type A)/arginine (Arg) or (type B) polymorphism at position 192 of PON1 gene has been suggested with coronary artery disease (CAD) among patients with diabetes mellitus (DM). However, conflicting results have also been reported. Objectives: To investigate the relationship between PON1 gene (Gln192-Arg) poly-morphism and the presence, extent and severity of CAD in type 2 DM. Methods: The study comprised 180 patients recruited from those undergoing coronary angiography for suspected CAD, who were divided according to the presence or absence of CAD and DM into 4 groups;Group I (n = 40 patients) nondiabetic subjects without CAD, Group II (n = 45 patients) diabetic patients without CAD, Group III (n = 47 patients) non diabetic patients with CAD and Group IV (n = 48 patients) diabetic patients with CAD. PON1 (Gln192-Arg) genotype was assessed using polymerase chain reaction (PCR) followed by AlwI digestion. Results: The frequency of Gln allele (Type A) was significantly higher in group I and group II compared to group III and group IV (62.5%, 60% vs 38.3%, 31.25% respectively, p 100 mg/dL [OR 4.31, CI (1.25 - 12.5), P < 0.001], high density lipoprotein (HDL) cholesterol <40 mg/dL [OR 5.11, CI (1.79 - 16.33), P < 0.001] and PON1 192 Arg allele [OR 4.62, CI (1.67 - 13.57), P < 0.001] were significantly independent predictors of CAD. Conclusion: Arg allele of PON1 192 gene polymorphism is an independent risk factor for CAD and it is associated not only with the presence of CAD but also with its extent and severity and its impact is clearly more pronounced in diabetic patients.

Analysis of Single Nucleotide Polymorphism in Human Paraoxonase 1 Gene(Q192R) with Matrix-assisted Laser Desorption/Ionization Time-of-flight Mass Spectrometry

Introduction Single nucleotide polymorphisms （SNPs） are the most abundant DNA markers in the human genome occurring at a frequency of one in every 500--1000 nucleotides. A variety of methods have been used for the analysis of single nucleotide polymorphisms, including restriction fragment length polymorphism （RFLP）, direct sequencing by using laser-induced fluorescence detectionTM, fluorescence energy transfer, MALDI-TOF MS combined with primer extension or invasive cleavage, and fluorescence polarization. During the past two decades, mass spectrometry has become a very popular tool in the analysis of biomolecules and is perfectly suited to the analysis of single nucleotide polymorphisms （SNPs） due to its speed, low cost, and accuracy. In this work, we used MALDI TOF mass spectrometry to detect the fragments of restriction endonuclease hydrolysis of PCR products flanking a SNP located at paraoxonase 1（Q192R）. Compared with electrophoresis, this method requires less time of analysis and possess a higher accuracy.

Paraoxonase-1 gene in patients with chronic obstructive pulmonary disease investigation Q192R and L55M polymorphisms

BACKGROUND: The effect of increased oxidative stress on the development of chronic obstructive pulmonary disease(COPD) is well known. One of the antioxidative systems against oxidative stress in human body is paraoxonase(PON) enzyme that protects low density lipoproteins(LDL) against oxidation. This study aimed to explore the polymorphisms on PON1, Q192 R, L55 M genes of patients with COPD.METHODS: DNAs extraction was obtained from blood samples of 50 patients diagnosed with COPD and 50 patients as a control group who were presented to emergency clinic. Genotypes were obtained with polymerase chain reaction(PCR) and AIw I and Hsp92 II restriction enzymes were used for Q192 R and L55 M polymorphisms, respectively. Analysis of data was done with the Chi-square test and Fisher's exact test.RESULTS: A statistically significant difference in Q192 R polymorphism was found between the COPD patients and the control group(P=0.05). There was no statistically significant difference in L55 M polymorphisms between the patient and control groups(P>0.05). Q192 R polymorphism was significantly correlated with the PON1 gene and cigarette smoking; however other risk factors did not show any significant correlation with this polymorphism. Though L55 M polymorphism was significantly correlated with family history and tuberculosis, there was no significant correlation with other risk factors.CONCLUSION: We believe that more studies are needed to study the correlation of L55 M polymorphism with other factors.

Fast estimation of Michaelis-Menten constant of arylesterase with a pair of medium concentrations of substrate

Objective: To investigate the reliability for fast estimation of Michaelis-Menten constant (Km) with calibrated specific activity at only two medium concentrations of substrate by both simulation and experimentation with arylesterase (ArE)as model. Methods: Initial rates were simulated by randomly inserting uniform absolute error, and the experimental initial rates of ArE were determined by measuring the increaser of product absorbance. Calibrated specific activities at two substrate concentrations were obtained by regression analysis, and Km was calculated according to Michaelis-Menten equation. Results: By simulation with calibrated specific activities at two medium substrate concentrations, Km could be calculated according to Michaelis-Menten equation with reasonable precision and accuracy. By experimentation with substrates of 2-naphthyl acetate, phenyl acetate, and p-nitrophenyl acetate, there were no differences between the mean and SD of Km of ArE for either substrate by this linear kinetic method and the Lineweaver-Burk plot. Conclusion: This linear kinetic method was reliable for fast estimation of the Km of some specified enzyme on its substrate of lower solubility or lower sensitivity for quantification by common methods.

Measurement of serum paraoxonase-1 activity in the evaluation of liver function

Paraoxonase-1 (PON1) is an esterase and lactonase synthesized by the liver and found in the circulation associated with high-density lipoproteins. The physiological function of PON1 seems to be to degrade specific oxidized cholesteryl esters and oxidized phospholipids in lipoproteins and cell membranes. PON1 is, therefore, an antioxidant enzyme. Alterations in circulating PON1 levels have been reported in a variety of diseases involving oxidative stress including chronic liver diseases. Measurement of serum PON1 activity has been proposed as a potential test for the evaluation of liver function. However, this measurement is still restricted to research and has not been extensively applied in routine clinical chemistry laboratories. The reason for this restriction is due to the problem that the substrate commonly used for PON1 measurement, paraoxon, is toxic and unstable. The recent development of new assays with non-toxic substrates makes this proposal closer to a practical development. The present editorial summarizes PON1 biochemistry and function, its involvement with chronic liver impairment, and some aspects related to the measurement of PON1 activity in circulation.

Inhibitory effect of the paraoxonase gene on the formation of rabbit coronary atherosclerosis

Objective:To observe the effect on the inhibition of coronary atherosclerosis hardening of the paraoxonase gene(PON-1) which transfected to the rabbit epicardial adipose tissue.Methods: Rabbit coronary atherosclerosis model was established by high-fat feeding,liposome-encapsulated recombinant plasmid pEGFP-PON-1 50μL was injected to the rabbit pericardial cavity,and was harvested 4 weeks after transfection.Results:The epicardial fat transfected PON-1 gene had effect on the high lipid level.It significantly increased expression of PON-1 in peripheral arterial vascular tissue(P【0.05);and significantly reduced total cholesterol and low-density lipoprotein cholesterol levels(P【0.05).and the thickness ratio of coronary artery intima/ media(P【0.05).Conclusions:The injection of the PON-1 gene in the pericardial cavity can effectively suppress the formation of coronary atherosclerosis.

Impact of antibacterial drugs on human serum paraoxonase-1(hPON1)activity:an in vitro study

Objective:To investigate the in vitro effects of the antihacterial drugs,mcropenem trihydrate.piperacillin sodium,and cefoperazone sodium,on the activity of human serum paraoxonase mPOND.Methods:hPQN1 was purified from human serum using simple chromatographic methods.including DEAE-Sephadex anion exchange and Sephadex G-200 gel filtration chromatography.Results:The three antihacterial drugs decreased in vitro hPON1 activity.Inhibition mechanisms meropcnem trihydrate was noncompetitive while piperacillin sodium and cefoperazone sodium were competitive.Conclusions:Our results showed that antihacterial drugs significantly inhibit hPON1 activity,both in vitro,with rank order meropenem trihydrate piperacillin sodium cefoperazone sodium in vitro.

Paraoxonase 2 Gene (Cys³¹¹-Ser) Polymorphism and the Risk of Coronary Artery Disease

Background: Human paraoxonase-2(PON2) which is exclusively intracellular possesses unique properities that distinguish it from PON1 and PON3. Recently, it was demonstrated that PON2 protects against atherosclerosis by preventing LDL oxidation. Emerging evidences have proposed that genetic variations in the PON2 gene may be associated with coronary artery disease (CAD). Objectives: To investigate the relationship between a common PON2 gene (Cys311-Ser) polymorphism and the presence and extent of CAD. Methods: The study comprised 112 patients recruited from those undergoing coronary angiography for suspected CAD, who were divided according to the presence or absence of CAD into 2 groups Group I including 62 patients with CAD and Group II including 50 patients proved to have normal coronaries. All the subjects included in the study were genotyped for the (Cys311-Ser) polymorphism of PON2 gene using RCR-RFLP. Results: The frequency of Cys allele was significantly higher in group I compared to Group II (77.4% vs. 56% respectively, P < 0.01). Patients with vessel score 3 had significantly higher severity score and higher Cys allele frequency than patients with vessel score 2, the latter group had also significantly higher severity score and Cys allele frequency than patients with vessel score 1. In multivariate logistic regression analysis of different variables for prediction of CAD, age [OR 3.79, CI (1.33 - 12.7), P < 0.01], smoking [OR 0.71, CI (0.23 - 7.81), P 311 Cys allele [OR 5.67, CI (1.99 - 14.77), P < 0.001] were significantly independent predictors of CAD. Conclusion: Cys allele of PON2 311 gene polymorphism is an independent risk factor for CAD and it is associated not only with the presence of CAD but also with its extent and severity.

Effect of paraoxonase1 gene polymorphism on carotid plaque and cerebral infarction in Hainan population

Objective:To investigate the effect of paraoxonase 1 gene polymorphism on carotid plaque stability with cerebral infarction in Hainan population.Methods:277 patients of caroticl plaque With cerebral infarction who underwent physical examination in a hospital in Hainan from 2015 to another awarding 2018 were selected as the experimental group and the 363 people who no cerebral infarction as the Analytical methods:control group.The clinical data analyzed.DNA was collected from peripheral blood of two groups of patients and genotyped by flight mass analytical methods.''AG and GG could be detected by rs3917538.The distribution frequencies of The three genotypes in The control group accorded with Hardy-Weinberg equilibrium.Results:The distribution frequencies of AA,AG and GG in the control group were 97(26.7%),175(48.2%)and 91(25.1%)respectively.In the experimental group,the distribution frequencies were 76(27.4%),136(49.1%)and 65(23.5%).There were no statistical differences among the three detection methods of co-dominant model,Dominant model and recessive model.There was no difference in the frequency of allele A and G between groups.Conclusion:Polymorphism of paraoxonase 1 gene rs3917538 has No significant effect on carotid plaque formation and cerebral infarction in Hainan population.The Supplementary sample size to add more SNP research sites for further study,It is expected to further Revral the relationship between PON1and carotial piaque complicatecl with cerebral infarction in Hainan.

Serum paraoxonase activity and protein thiols in patients with hyperlipidemia

Objective: In the present study we evaluated the paraoxonase activity and protein thiols level in south Indian population with newly diagnosed hyperlipidemia.Methods: The study was conducted on 55 newly diagnosed hyperlipidemic patients and 57 healthy controls.Serum paraoxonase activity and protein thiols were estimated by spectrophotometeric method and lipid profile by enzymatic kinetic assay method.Results: Serum paraoxonase activity,protein thiols and high density lipoprotein levels were low and total cholesterol,triglycerides and low density lipoprotein levels were high in patients with hyperlipidemia compared to healthy controls(P<0.01).Serum paraoxonase activity correlated positively with protein thiols and high density lipoprotein(P<0.01).Conclusion: Decreased paraoxonase activity and protein thiols were found in patients with hyperlipidemia.This may indicate the susceptibility of this population to accelerated atherogenesis and protein oxidation.

Correlation of serum arylesterase activity on phenylacetate estimated by the integrated method to common classical biochemical indexes of liver damage

The correlation of serum arylesterase(PON1) activity on phenylacetate determined by an integrated method to clas-sical biochemical indexes of liver damage was investigated for the use of PON1 activity to evaluate liver damage.PON1 reaction curve as absorbance at 270 nm for 0.20 mmol/L phenylacetate hydrolysis was analyzed by the integrated method to determine maximal PON1 reaction rate.Classical biochemical indexes of liver damage were determined routinely.The 95% confidence threshold of PON1 activity in sera from healthy individuals was 2.12 mkat/L [(4.73±1.31) mkat/L,n=105].PON1 activity in clinical sera was closely correlated to serum albumin,total protein and the ratio of albumin to globulins,but was weakly correlated to both direct and total bilirubin in serum.There were no correlations of PON1 activity to γ-glutamyltransferase,alkaline phos-phatase,alanine aminotransferase and aspartate aminotransferase.Among 127 clinical sera with PON1 activity>2.12 mkat/L,there were 92% healthy individuals examined by albumin,90% healthy individuals examined by total protein,88% healthy individuals examined by total bilirubin,86% healthy individuals examined by direct bilirubin and 64% healthy individuals examined by the ratio of albumin to globulins,respectively.In each group of healthy individuals judged by classical biochemical indexes of close correlation to PON1 activity,percentage of healthy individuals examined by PON1 activity was always >80%.These results suggested PON1 activity on phenylacetate estimated by the integrated method was also suitable for the evaluation of liver damage.

STUDY ON THE RELATIONSHIP BETWEEN PARAOXONASE GENE POLYMORPHISM AND CORONARY ARTERIAL DISEASE IN NIDDM

Objective To ascertain the relationship between paraoxonase gene (PON) and the morbidity of coronary arterial disease (CAD) in Chinese non-insulin-dependent diabetes mellitus (NIDDM) patients. Methods The exons of PON gene were screened by polymerase chain reaction-denaturing gradient gel elec-trophoresis in 49 NIDDM patients complicated with CAD, 49 NIDDM and 101 healthy control cases of Chinese population. Results Gln-Arg191 polymorphism of the PON gene was detected in Chinese with the AIR allele frequency 0.39 and 0. 61 respectively. The genotype distribution (AA, AR and RB) of the PON gene polymor-phism was significantly different between NIDDM patients complicated with CAD and controls (NIDDM and healthy subjects). The former had a significantly higher B allele frequency (0. 79 vs 0. 62 and 0. 61, P < 0. 01). Conclusion Gln-Arg191 polymorphism of the PON gene is associated with CAD morbidity in Chinese NJDDM patients and B allele might be a risk factor.