Paraoxonase (PON)-1: a brief overview on genetics, structure, polymorphisms and clinical relevance

Thioredoxin Domain Containing 5 Suppression Elicits Serum Amyloid A-Containing High-Density Lipoproteins

Thioredoxin domain containing 5 (TXNDC5) is a protein disulfide isomerase involved in several diseases related to oxidative stress, energy metabolism and cellular inflammation. In a previous manuscript, a negative association between fatty liver development and hepatic Txndc5 expression was observed. To study the role of TXNDC5 in the liver, we generated Txndc5-deficient mice. The absence of the protein caused an increased metabolic need to gain weight along with a bigger and fatter liver. RNAseq was performed to elucidate the putative mechanisms, showing a substantial liver overexpression of serum amyloid genes (Saa1, Saa2) with no changes in hepatic protein, but discrete plasma augmentation by the gene inactivation. Higher levels of malonyldialdehyde, apolipoprotein A1 and platelet activating factor-aryl esterase activity were also found in serum from Txndc5-deficient mice. However, no difference in the distribution of high-density lipoproteins (HDL)-mayor components and SAA was found between groups, and even the reactive oxygen species decreased in HDL coming from Txndc5-deficient mice. These results confirm the relation of this gene with hepatic steatosis and with a fasting metabolic derive remedying an acute phase response. Likewise, they pose a new role in modulating the nature of HDL particles, and SAA-containing HDL particles are not particularly oxidized.

The Effects of Acute and Chronic Exercise on Paraoxonase-1 (PON1): A Systematic Review With Meta-Analysis

Purpose: To determine the acute and chronic effects of exercise on Paraoxonase-1 (PON1) concentration and activity. Methods: A literature search was performed using 16 electronic databases. Effect sizes (ES) were computed and two-tailed α values < .05 and non-overlapping 95% confidence intervals (95%CI) were considered statistically significant. Heterogeneity, inconsistency (I²), and small-study effects using the LFK index were examined. Results: Eighteen studies (n = 377 participants) met the criteria for inclusion. The acute effects of exercise on PON1 concentration were trivial and non-significant (ES = -.03, 95%CI = -.39 to .34, p > .05), heterogeneous (p = .05), moderately inconsistent (I² = 48%), with minor asymmetry (LFK index = 1.34). The chronic effects of exercise on PON1 concentration were also trivial and non-significant (ES = -.04, 95%CI = -.53 to.45, p > .05), homogenous (p = .65), displayed low inconsistency (I² = 0%), and minor asymmetry (LFK index = -1.14). The acute effects of exercise on PON1 activity were trivial and non-significant (ES = .11, 95%CI = -.02 to.24, p > .05), homogenous (p = .85), showed low inconsistency (I² = 0%), and no asymmetry (LFK index = .82). The chronic effects of exercise on PON1 activity were trivial and non-significant (ES = .31, 95%CI = -.03 to.65, p > .05), homogenous (p = .17), moderately inconsistent (I² = 36%), with no asymmetry (LFK index = .60). Conclusion: Acute and chronic exercise training, overall, exerted a trivial effect on PON1 concentration and activity.

Association of PON-1 polymorphism with susceptibility to and severity of ischemic stroke in the Chinese population

Aim: The authors aimed to investigate whether polymorphisms of PON-1 were associated with the susceptibility to and severity of ischemic stroke (IS). Methods: In this study, 302 IS patients and 303 healthy controls were enrolled. Polymorphisms rs854560 and rs854572 of PON-1 were detected using SNaPshot single-nucleotide polymorphism typing technology. Results: The rs854572 polymorphism of the PON-1 gene showed a significant correlation with IS, and its GG genotype reduced the risk of IS (recessive model, p = 0.001). The GG genotype was also associated with mild stroke (p = 0.032). No association was observed between rs854560 and IS. Conclusion: PON-1 rs854572 polymorphism was related to the risk of IS and could be a biomarker to access the severity of IS.

The Impact of Different rs3917538 Genotypes with the PON-1 Activity, Atherosclerosis Severity in Patients of Coronary Atherosclerosis

Background: Coronary atherosclerosis is one of the coronary artery diseases (CAD) responsible for a significant percentage of mortality and morbidity in Iraqi subjects. Atherosclerosis compresses about 17 million death cases; 45% are under the age of 70. The improvement in atherosclerosis disease management paly a critical role in preventing this disease; despite that, new risk factors have been studied, including genetic studies. Many polymorphisms have been associated with coronary atherosclerosis in different ethnic populations. Paraoxonase is an enzyme located on HDL in serum. PON acts as a protective factor or agent against oxidative modification of LDL, suggesting that it could play an essential and influential role in atherosclerotic processes prevention. Objective: To evaluate the rs3917538 genotypes in the PON-1 gene associated with the coronary atherosclerosis risk and the effect of this single nucleotide polymorphism on the serum activity of PON-1 and the severity of coronary atherosclerosis. Methods: A case-control study included sixty patients diagnosed with coronary atherosclerosis and sixty healthy volunteers diagnosed with angiography examination. The study was carried out during the period from February 2019 till June 2020. Serum PON-1 was measured by fluorometric technique, and the genetic assessment was by RT-PCR technique. Results: The activity for PON-1 in patients was significantly lower than controls; the median activity of PON-1 in controls was 197.32 mU/ml, which was higher than that of patients (median =163.46 mU/ml). There was an impact of rs3917538 genotypes on the severity of the disease, P=0.041. The rs3917538 genotypes have no association with the risk of coronary atherosclerosis and the activity of PON-1. Conclusion: The measurement of serum PON-1 activity may help in the diagnosis  of coronary atherosclerosis patients. The rs3917538 genotypes in the PON-1 gene among the patient’s group impact the severity of coronary atherosclerosis.

PON1 (Paraoxonase 1) Q192R gene polymorphism in ischemic stroke among North Indian population

Background:

PON1 is an High Density Lipoprotein (HDL)-associated esterase. Two common polymorphisms in the PON1 gene, Q192R and L55M substitutions, determine the inter-individual variation in PON1 activity. The association of these polymorphisms with the risk of ischemic stroke remains controversial. In the present study, the role of PON1 Q192R gene polymorphism in ischemic stroke was studied in the Indian population.

Design and Methods:

In the present case-control study, the PON1 Q192R gene polymorphism was screened in ischemic stroke patients (n: 63) and age, sex-matched controls (n: 63) using thePolymerase Chain Reaction-Restriction Segment Length Polymorphism (PCR-RFLP) method.

Results:

The mean age of stroke presentation was 58.11 ± 15.4 years. A total of 17.4% cases presented with young stroke (<45 years age) and 9.52% cases were seen to have a recurrent stroke. The distribution of -192Q/R PON1 gene polymorphism was not seen to differ between cases and controls. The traditional stroke risk factors did not have any effect on the PON1 genotype expression. A multivariate logistic regression analysis was done in order to assess an independent association of age, gender, traditional stroke risk factors, and PON1 polymorphism with acute ischemic stroke. However, neither the RR genotype nor the presence of the R allele was associated with an increase in the risk of acute ischemic stroke (OR [RR genotype]-4.76, P value: 0.24, 95% CI: 0.3497–64.8531; OR [R allele]-0.94, P value: 0.90, 95% CI: 0.3516–2.4989).

Conclusion:

PON1 Q192R gene polymorphism is not associated with an increased risk of acute ischemic stroke in the North Indian population. Further studies with a larger sample size are needed before PON1 Q192R gene polymorphism can be considered as a genetic risk factor for ischemic stroke.

Arylesterase activity of paraoxonase 1 in patients with primary hypertension

Introduction

Paraoxonase 1 is an enzyme associated with high-density lipoprotein fraction and is considered to present antioxidant activity.

Objectives

The aim of the study was to assess the arylesterase activity of paraoxonase 1 (PON1) in the serum of patients with hypertension, due to effect of therapy and before treatment. Patients and Methods. The study was conducted in 76 patients with primary hypertension and 28 volunteers for the control group. Hypertensive subjects were assigned to one of three groups: well controlled (n=25), poorly controlled (n=26), and newly diagnosed before therapy (n=25) hypertension. We evaluated metabolic parameters in all participants using routine laboratory methods, as well as arylesterase activity of PON1.

Results

The four study groups differed with arylesterase activity of PON1 and the highest levels were found in patients with well controlled hypertension and the lowest in newly diagnosed. All patients diagnosed with hypertension presented negative correlations between PON1 and systolic and diastolic blood pressure.

Conclusions

Effective treatment of hypertension could result in increased PON1 activity, despite unfavorable homocysteine concentrations in blood. Untreated hypertension might decrease activity of PON.

Paraoxonase 1 (PON1) L55M and Q192R polymorphisms are not associated with chronic kidney disease in Thai individuals with type 2 diabetes

BACKGROUND

Decreased paraoxonase 1 (PON1) activity and PON1 polymorphisms have been found to be associated with chronic kidney disease (CKD) in type 2 diabetes mellitus (T2DM).

OBJECTIVE

This study aimed to investigate the association of the PON1 L55M and Q192R polymorphisms with CKD in T2DM, as well as their relationship with PON1 activity.

METHODS

A total of 166 T2DM patients, including 83 CKD patients and 83 non-CKD patients, were recruited. Biochemical parameters and paraoxonase (PONase) and arylesterase (AREase) activities were measured. The PON1 L55M and Q192R polymorphisms were analysed by a polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) method. Data were analysed using the chi-square test, Student's t-test and logistic regression analysis.

RESULTS

Total cholesterol, TGs, LDL-C and Cr were significantly higher in CKD patients than in non-CKD patients. In contrast, the estimated glomerular filtration rate (eGFR) and AREase activity were significantly lower in CKD patients than in non-CKD patients (P < .05). The genotype and allele frequencies of the PON1 L55M and Q192R polymorphisms were not significantly different between CKD and non-CKD patients. Multivariate logistic regression analysis showed no association between the PON1 L55M and Q192R polymorphisms and CKD in T2DM. In addition, among all patients, patients with the PON1 LM genotype had significantly lower PONase activity than those with the LL genotype (P < .05). Among all patients, CKD patients and non-CKD patients, those with the PON1 RR genotype had significantly higher PONase activity but lower AREase activity than patients with the QR and QQ genotypes (P < .05).

CONCLUSIONS

PON1 activity was influenced by the PON1 L55M and Q192R polymorphisms. However, the PON1 L55M and Q192R polymorphisms may not be considered genetic biomarkers for CKD in T2DM.

Genetic variants of PON1, GSTM1, GSTT1, and locus 9p21.3, and the risk for premature coronary artery disease in Yucatan, Mexico

OBJECTIVE

Genetic variants of PON1, rs70587, rs662, rs854560, GSTM1, and GSTT1 and two single nucleotide polymorphisms (SNP) at 9p21.3 locus, rs1333049, and rs2383207; were evaluated in association with the risk for premature coronary artery disease (CAD) in a population of Yucatan, Mexico. These genes are involved in the inactivation of pro-oxidants and pro-inflammatory mediators, lipid and xenobiotic metabolism, detoxification of reactive oxygen species, and regulation of cellular proliferation playing key roles in the pathogenesis of atherosclerosis.

METHODS

We conducted a matched case-control study with 98 CAD cases and 101 healthy controls. Genotyping of PON1 and 9p21.2 SNP was performed by real time-PCR and for GSTM1 and GSTT1 with multiplex-PCR. Odds ratios (OR) were calculated to estimate association and generalized multifactor dimensionality reduction (GMDR) algorithm to identify gene-gene and gene-environment interactions.

RESULTS

The distribution of all allele/genotype frequencies in controls was within Hardy-Weinberg expectations (p > .05) except for GSTM1. The allele/genotype frequencies of the GSTT1 null were significantly higher in CAD cases than in controls, suggesting association with higher risk for developing CAD. The other SNPs did not show any significant independent association with premature CAD. GMDR revealed a significant interaction between GSTT1 and LL55 genotype. Likewise, the body mass index (BMI) and smoking also showed an interaction with GSTT1.

CONCLUSION

The GSTT1 null allele/genotype is associated with an increased risk of developing premature CAD, the effect of which is not modified by cardiovascular risk factors in the population of Yucatan.

Genetic associated complications of type 2 Diabetes Mellitus: a review

According to the International Diabetes Federation, the number of adults (age of 20-79) being diagnosed with Diabetes Mellitus (DM) have increased from 285 million in year 2009 to 463 million in year 2019 which comprises of 95% Type 2 DM patient (T2DM). Research have claimed that genetic predisposition could be one of the factors causing T2DM complications. In addition, T2DMcomplications cause an incremental risk to mortality. Therefore, this article aims to discuss some complications of T2DM in and their genetic association. The complications that are discussed in this article are diabetic nephropathy, diabetes induced cardiovascular disease, diabetic neuropathy, Diabetic Foot Ulcer (DFU) and Alzheimer's disease. According to the information obtained, genes associated with diabetic nephropathy (DN) are gene GABRR1 and ELMO1 that cause injury to glomerular. Replication of genes FRMD3, CARS and MYO16/IRS2 shown to have link with DN. The increase of gene THBS2, NGAL, PIP, TRAF6 polymorphism, ICAM-1 encoded for rs5498 polymorphism and C667T increase susceptibility towards DN in T2DM patient. Genes associated with cardiovascular diseases are Adiponectin gene (ACRP30) and Apolipoprotein E (APOE) polymorphism gene with ξ2 allele. Haptoglobin (Hp) 1-1 genotype and Mitochondria Superoxide Dismutase 2 (SOD2) plays a role in cardiovascular events. As for genes related to diabetic neuropathy, Janus Kinase (JAK), mutation of SCN9A and TRPA1 gene and destruction of miRNA contribute to pathogenesis of diabetic neuropathy among T2DM patients. Expression of cytokine IL-6, IL-10, miR-146a are found to cause diabetic neuropathy. Besides, A1a16Va1 gene polymorphism, an oxidative stress influence was found as one of the gene factors. Diabetic retinopathy (DR) is believed to have association with Monocyte Chemoattractant Protein-1 (MCP-1) and Insulin-like Growth Factor 1 (IGF1). Over-expression of gene ENPP1, IL-6 pro-inflammatory cytokine, ARHGAP22's protein rs3844492 polymorphism and TLR4 heterozygous genotype are contributing to significant pathophysiological process causing DR, while research found increases level of UCP1 gene protects retina cells from oxidative stress. Diabetic Foot Ulcer (DFU) is manifested by slowing in reepithelialisation of keratinocyte, persistence wound inflammation and healing impairment. Reepithelialisation disturbance was caused by E2F3 gene, reduction of Tacl gene encoded substance P causing persistence inflammation while expression of MMp-9 polymorphism contributes to healing impairment. A decrease in HIF-1a gene expression leads to increased risk of pathogenesis, while downregulation of TLR2 increases severity of wound in DFU patients. SNPs alleles has been shown to have significant association between the genetic dispositions of T2DM and Alzheimer's disease (AD). The progression of AD can be due to the change in DNA methylation of CLOCK gene, followed with worsening of AD by APOE4 gene due to dyslipidaemia condition in T2DM patients. Insulin resistance is also a factor that contributes to pathogenesis of AD.

Electronic and Tobacco Cigarettes Alter Polyunsaturated Fatty Acids and Oxidative Biomarkers

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Association of M55L and Q192R polymorphisms of paraoxonase 1 gene (PON1) with recurrent pregnancy loss risk: A case-control study

Background

Recurrent pregnancy loss (RPL) refers to the incidence of two or more abortions before the first half of pregnancy. Oxidative stress has been hypothesized to play a central role in RPL.

Objective

To investigate the relationship between Q192R and L55M polymorphisms of PON1 as antioxidant enzyme and the risk of RPL.

Materials and Methods

In this case–control study, 110 women with RPL (case) and 110 healthy fertile women (control) referred to the Research and Clinical Center for Infertility, Shiraz, Iran were enrolled. Genomic DNA was extracted from the peripheral blood in all participants. Polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism method.

Results

Statistical analysis of Q192R polymorphism showed a significant difference for the RR genotype between the case and control group (OR = 11, CI = 1.39–86.87, p = 0.005) but none for the QR and QQ genotypes. No significant association was observed between the R and Q allelic frequency in the RPL participants compared to the control group (p = 0.53). Also, statistical analysis of the L55M polymorphism for MM genotype in the case group compared with the control group showed a significant difference (OR = 3.59, CI = 0.97–13.30, p = 0.042), but none for the LM and LL genotypes.

Conclusion

The findings showed a significant correlation between the Q192R polymorphisms and the L55M PON1 enzyme and RPL in this study population.

A targeted multi-omics approach reveals paraoxonase-1 as a determinant of obesity-associated fatty liver disease

Background

The multifactorial nature of non-alcoholic fatty liver disease cannot be explained solely by genetic factors. Recent evidence revealed that DNA methylation changes take place at proximal promoters within susceptibility genes. This emphasizes the need for integrating multiple data types to provide a better understanding of the disease’s pathogenesis. One such candidate gene is paraoxonase-1 (PON1). Substantial interindividual differences in PON1 are apparent and could influence disease risk later in life. The aim of this study was therefore to determine the different regulatory aspects of PON1 variability and to examine them in relation to the predisposition to obesity-associated fatty liver disease.

Results

A targeted multi-omics approach was applied to investigate the interplay between PON1 genetic variants, promoter methylation, expression profile and enzymatic activity in an adult patient cohort with extensive metabolic and hepatic characterisation including liver biopsy. Alterations in PON1 status were shown to correlate with waist-to-hip ratio and relevant features of liver pathology. Particularly, the regulatory polymorphism rs705379:C > T was strongly associated with more severe liver disease. Multivariable data analysis furthermore indicated a significant association of combined genetic and epigenetic PON1 regulation. This identified relationship postulates a role for DNA methylation as a mediator between PON1 genetics and expression, which is believed to further influence liver disease progression via modifications in PON1 catalytic efficiency.

Conclusions

Our findings demonstrate that vertical data-integration of genetic and epigenetic regulatory mechanisms generated a more in-depth understanding of the molecular basis underlying the development of obesity-associated fatty liver disease. We gained novel insights into how NAFLD classification and outcome are orchestrated, which could not have been obtained by exclusively considering genetic variation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-021-01142-1.

Human carboxylesterases and fluorescent probes to image their activity in live cells

Human carboxylesterases (CESs) are serine hydrolases that are responsible for the phase I metabolism of an assortment of ester, amide, thioester, carbonate, and carbamate containing drugs. CES activity is known to be influenced by a variety of factors including single nucleotide polymorphisms, alternative splicing, and drug-drug interactions. These different factors contribute to interindividual variability of CES activity which has been demonstrated to influence clinical outcomes among people treated with CES-substrate therapeutics. Detailed exploration of the factors that influence CES activity is emerging as an important area of research. The use of fluorescent probes with live cell imaging techniques can selectively visualize the real-time activity of CESs and have the potential to be useful tools to help reveal the impacts of CES activity variations on human health. This review summarizes the properties of the five known human CESs including factors reported to or that could potentially influence their activity before discussing the design aspects and use considerations of CES fluorescent probes in general in addition to highlighting several well-characterized probes.

Cloning, sequence analysis, and tissue expression of marmoset paraoxonase 1

Paraoxonase (PON) plays roles in the metabolism of organophosphate xenobiotics and drugs. Despite the importance of marmosets for research into drug metabolism and pharmacokinetics, marmoset paraoxonase has not yet been fully characterized. Consequently, we identified the PON1 gene in the marmoset genome by sequence homology analysis. Marmoset PON1 cDNA containing an open reading frame (1065 bp) was successfully cloned from marmoset liver by reverse transcription-polymerase chain reaction. The deduced amino acid sequence (355 amino acids) has approximately 93% identity with the human ortholog and contains important amino acid residues for substrate binding and calcium ion coordination. According to a phylogenetic tree of PON1 amino acid sequences constructed using data from seven animal species, marmoset PON1 is closer to human PON1 than it is to the PON1 orthologs of experimental animals such as pigs, rabbits, rats, and mice. Marmoset PON1 mRNA was predominantly expressed in liver among the five tissues examined. Marmoset PON1 protein secreted into plasma was detected by immunoblotting. The paraoxon-hydrolyzing activity in plasma was higher in marmosets than in humans. Based on these data, we concluded that marmoset and human PON1 have similar characteristics with regard to genomic structure, amino acid sequences, and tissue distribution.

Assessment of hepatic oxidative damage, paraoxonase-1 activity, and lipid profile in cattle naturally infected with Ba7besia bigemina

Naturally occurring Babesia bigemina infection in cattle is associated with changes in the status of oxidative stress, trace elements, sialic acid, and cholinesterase activity in blood. However, to date there is no description of hepatic damage in the infected animals. More importantly, the majority of the above-mentioned causative factors are synthesized or stored in the liver. Therefore, this study was undertaken to evaluate biomarkers of hepatic function, paraoxonase-1 activity, and lipid profile in 13 cattle infected with B. bigemina which did not respond to standard treatment. The animals were necropsied and the histopathology of the liver and DNA damage of hepatocytes were examined. Blood analysis revealed a significant parasitemia burden-dependent increase in the activities of hepatic enzymes and total bilirubin and a decrease in albumin concentrations in the infected cattle compared to the control ones. Paraoxonase-1 activity was remarkably lower in the infected animals than the control. A significant decrease in the blood concentrations of total cholesterol, low density lipoprotein, and high density lipoprotein and a significant increase in the triglyceride concentration were observed in the infected animals. Severe oxidative damages were also recorded in the haptic tissue evidenced by significant alterations in the activities of antioxidant enzymes, suppression of total antioxidant capacity, and oxidation of biomolecules. Congestion of blood vessels, bile duct hyperplasia, and hepatocyte necrosis were the evident histopathologic findings. Our results revealed significant changes in the indices of liver function in the diseased cattle, leading to the conclusion that the parasite can potentially cause liver dysfunction.

Pterostilbene Inhibits Dyslipidemia-Induced Activation of Progenitor Adipose Gene Under High-Fat Diet and Radiation Stressor

Repeated exposure to ionizing radiation has been reported to increase the risk of chronic metabolic disorders such as systemic hyperlipidemia and intracellular lipid accumulation that might lead to diabetes-induced heart disease. The purpose of this study was to investigate the effect of pterostilbene on high-fat diet rats suffering from ionizing radiation-induced hyperlipidemia. High-fat diet rats showed an increase in body weight and body fat compared with rats fed with normal chow. Pterostilbene and Orlistat treatments resulted in lower body weight and body fat gain, insulin resistance, reduced lipid peroxidation with attenuated liver enzyme levels, and regulated lipogenesis-related genes in the HFD + IR rat group. Regulation of Peroxisome proliferator-activated receptor-γ (PPAR-γ) mRNA enhanced paraoxonase-1 (PON-1) and arylesterase (AE) activities and inhibited that of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA). It also increased the activities of plasma lecithin-cholesterol acyltransferase (LCAT) and lipoprotein lipase (LPL). Pterostilbene and Orlistat also corrected the alterations of serum leptin and adiponectin levels in lipidemic rats. Such findings provide evidence that Pterostilbene and Orlistat can act as normolipidemic agents that possess lipid-lowering effects and potential as a radioprotector.

The Relevance of Noncoding DNA Variations of Paraoxonase Gene Cluster in Atherosclerosis-Related Diseases

The human paraoxonase (PON) gene cluster is comprised of three contiguous genes (PON1, PON2 and PON3) of presumably common origin coding three lactonases of highly similar structure and substrate specificity. The catalytic activity of PON proteins is directed toward artificial organophosphates and in physiological conditions toward thiolactones and oxidized phospholipids. Consequently, PON enzymes are regarded as an effective defense against oxidative stress and, as a result, against atherosclerosis development. Additionally, both PON's serum activity and its concentration are influenced by several polymorphic variations in coding and noncoding DNA regions of the PON gene cluster remaining in linkage disequilibrium. Hence, the genetic polymorphism of the PON gene cluster may contribute to atherosclerotic process progression or deceleration. In this review the authors analyzed the relevance of noncoding DNA polymorphic variations of PON genes in atherosclerosis-related diseases involving coronary and peripheral artery disease, stroke, diabetes mellitus, dementia and renal disease and concluded that the effect of PON gene cluster' polymorphism has a considerable impact on the course and outcome in these conditions. The following PON genetic variations may serve as additional predictors of the risk of atherosclerosis in selected populations and individuals.

Pro-inflammatory Mediators and Oxidative Stress: Therapeutic Markers for Recurrent Angina Pectoris after Coronary Artery Stenting in Elderly Patients

BACKGROUND

Pro-inflammatory mediators and oxidative stress are related to severity of angina pectoris in patients with coronary heart disease.

OBJECTIVE

We evaluated the effects of pro-inflammatory mediators and oxidative stress on recurrent angina pectoris after coronary artery stenting in elderly patients.

METHODS

We determined the expression levels of malondialdehyde (MDA), acrolein (ACR), tumour necrosis factor-α (TNF-α), toll-like receptor 4 (TLR4), superoxide dismutase 3 (SOD3), paraoxonase-1 (PON-1), stromal cell-derived factor-1α (SDF-1α) and endothelial progenitor cells (EPCs) in elderly patients with recurrent angina pectoris after coronary artery stenting.

RESULTS

Levels of MDA, ACR, TNF-α and TLR4 were significantly increased (p<0.001), and levels of SOD3, PON-1, SDF-1α and EPCs were significantly decreased (p<0.001) in the elderly patients with recurrent angina pectoris after coronary artery stenting. MDA, ACR, TNF-α and TLR4 as markers of oxidative stress and pro-inflammatory mediators may have suppressed SOD3, PON-1, SDF-1α and EPCs as markers of anti-oxidative stress/anti-inflammatory responses. Oxidative stress and pro-inflammatory mediators were important factors involved in recurrent angina pectoris of elderly patients after coronary artery stenting.

CONCLUSION

Oxidative stress and pro-inflammatory mediators could be considered as potential non-invasive prognostic, predictive and therapeutic biomarkers for stable recurrent angina and recurrent unstable angina in the elderly patients after coronary artery stenting.

Genetic Variability of Antioxidative Mechanisms and Cardiotoxicity after Adjuvant Radiotherapy in HER2-Positive Breast Cancer Patients

Background

Breast cancer treatment is associated with the occurrence of various cardiac adverse events. One of the mechanisms associated with cardiotoxicity is oxidative stress, against which cells are protected by antioxidative enzymes. Genetic variability of antioxidative enzymes can affect enzyme activity or expression, which modifies the ability of cells to defend themselves against oxidative stress and could consequently contribute to the occurrence of treatment-related cardiotoxicity. Our aim was to evaluate the association of common polymorphisms in antioxidative genes with cardiotoxicity after adjuvant radiotherapy (RT) in HER2-positive breast cancer patients.

Methods

Our retrospective study included 101 HER2-positive early breast cancer patients who received trastuzumab and adjuvant RT. We isolated DNA from buccal swabs and used competitive allele-specific PCR for genotyping of PON1 rs854560 and rs662, GSTP1 rs1138272 and rs1695, SOD2 rs4880, CAT rs1001179, and HIF1 rs1154965 polymorphisms. N-terminal pro B-type natriuretic peptide (NT-proBNP), left ventricular ejection fraction, and NYHA class were used as markers of cardiotoxicity. We used logistic regression to evaluate the association of genetic factors with markers of cardiotoxicity.

Results

Carriers of at least one polymorphic PON1 rs854560 allele were less likely to have increased NT-proBNP (OR = 0.34; 95% CI = 0.15-0.79; P = 0.012), even after adjustment for age (OR = 0.35; 95% CI = 0.15-0.83; P = 0.017). Carriers of at least one polymorphic PON1 rs662 allele were more likely to have increased NT-proBNP (OR = 4.44; 95% CI = 1.85-10.66; P = 0.001), even after adjustment for age (OR = 5.41; 95% CI = 2.12-13.78; P < 0.001). GSTP1 rs1695 was also associated with decreased NT-proBNP in the multivariable analysis (P = 0.026), while CAT rs1001179 was associated with NYHA class in the univariable (P = 0.012) and multivariable analysis (P = 0.023).

Conclusion

In our study, polymorphisms PON1 rs662 and rs854560, CAT rs1001179, and GSTP1 rs1695 were significantly associated with the occurrence of cardiac adverse events after adjuvant RT and could serve as biomarkers contributing to treatment personalization.

Whole-Body Cryostimulation Improves Inflammatory Endothelium Parameters and Decreases Oxidative Stress in Healthy Subjects

BACKGROUND

The purpose of this study was to estimate the effect of whole-body cryostimulation (WBC) and subsequent kinesiotherapy on inflammatory endothelium and oxidative stress parameters in healthy subjects.

METHODS

The effects of ten WBC procedures lasting 3 min per day and followed by a 60-min session of kinesiotherapy on oxidative stress and inflammatory endothelium parameters in healthy subjects (WBC group n = 32) were analyzed. The WBC group was compared to a kinesiotherapy only (KT; n = 16) group. The following parameters were estimated one day before the start, and one day after the completion of the studies: oxidative stress parameters (the total antioxidant capacity of plasma (FRAP), paraoxonase-1 activity (PON-1), and total oxidative status (TOS)) and inflammatory endothelium parameters (myeloperoxidase activity (MPO), serum amyloid A (SAA), and sCD40L levels).

RESULTS

A significant decrease of PON-1 and MPO activities and TOS, SAA, and sCD40L levels as well as a significant FRAP increase were observed in the WBC group after the treatment. In addition, the SAA levels and PON-1 activity decreased significantly after the treatment in both groups, but the observed decrease of these parameters in the WBC group was higher in comparison to the KT group.

CONCLUSION

WBC procedures have a beneficial impact on inflammatory endothelium and oxidative stress parameters in healthy subjects, therefore they may be used as a wellness method.

A Multi-Omics Analysis of PON1 Lactonase Activity in Relation to Human Health and Disease

Paraoxonase 1 (PON1) enzyme has antioxidative properties and is present in mammalian blood and several other body fluids. In blood, PON1 is usually integrated into the high-density lipoprotein (HDL) cholesterol. PON1 is a highly versatile enzyme displaying diverse functions such as arylesterase, lactonase, and paraoxonase, among others. PON1 activities are usually investigated with artificial substrates, for example, dihydrocoumarin and thiobutyl butyrolactone for lactonase activity. The PON1 enzyme activities measured with different substrates tend to be falsely assumed as being equivalent in the literature, although there are poor or weak correlations among the PON1 enzyme activities with different substrates. In addition, and despite our knowledge of the factors influencing PON1 paraoxonase and arylesterase activities, there is little knowledge of PON1 lactonase activity variations and attendant mechanisms. This is important considering further that the lactonase activity is the native activity of PON1. We report here a multi-omics analysis of PON1 lactonase activity. The influence of genetic variations, particularly of single nucleotide polymorphisms and epigenetic, proteomic, and lipidomic variations on PON1 lactonase activity are reviewed. In addition, the influence of various environmental, clinical, and demographic variables on PON1 lactonase activity is discussed. Finally, we examine the associations between PON1 lactonase activity and health states and common complex diseases such as atherosclerosis, dementias, obesity, and diabetes. To the best of our knowledge, this is the first multi-omics analysis of PON1 lactonase activity with an eye to future applications in basic life sciences and translational medicine and the nuances of critically interpreting PON1 function with lactones as substrates.

Bariatric surgery decreases oxidative stress and protein glycosylation in patients with morbid obesity

BACKGROUND

There is growing evidence that oxidative stress (OS) is a critical factor linking obesity with its associated comorbidities, such as cardiovascular diseases.

AIM

To evaluate the degree of OS in people with morbid obesity and its relationship with glycoproteins, determined using 1H-NMR spectroscopy, before and after bariatric surgery (BS).

METHODS

In this observational cohort study, plasma from 24 patients with BMI ≥ 40 kg/m² (age: 21-65 years) was used to measure metabolites implicated in OS. We measured glycoprotein (GlycA, GlycB and GlycF) areas and shape factors (H/W = height/width).

RESULTS

One year after BS, oxidized low-density lipoprotein had decreased by 49% (P < .0001), malondialdehyde by 32% (P = .0019) and lipoprotein (a) by 21% (P = .0039). The antioxidant enzymes paraoxonase-1 and catalase increased after BS (43%, P < .0001 and 54%, P = .0002, respectively). Superoxide dismutase-2 had fallen 1 year after BS (32%, P = .0052). After BS, both the glycoprotein areas and shape factors decreased by 20%-26%. These glycoproteins were significantly correlated with OS parameters. The plasma atherogenic index was 63% higher in obese individuals than 1 year after BS and correlated positively with glycoproteins.

CONCLUSION

For the first time, we here demonstrate the relationship between OS parameters and glycoproteins in people with morbid obesity. So glycoproteins could therefore be a good indicator, together with the oxidative state to assess patient prognosis after BS.

Influence of Human Paraoxonase-1 Polymorphism (Q192R) on Serum Levels of Clinical Biomarkers Indicatives of Cardiovascular Diseases Risk in Mexican Women

Human paraoxonase-1 (PON1) is a hydrolytic enzyme related in the onset, establishment, and progression of inflammatory illnesses, including cardiovascular diseases (CVD). Therefore, the primary goal of this investigation was to determinate the influence of the PON1 gene polymorphism (Q192R) on prognostic biomarkers of CVD in women (n = 350) from San Luis Potosi, Mexico. For everyone enrolled, anthropometric, clinical, and biochemical measurements were acquired. Q192R polymorphism of the PON1 gene was assessed by real-time PCR using TaqMan probes. Also, quantification and/or calculation of suggested predictive CVD biomarkers were completed. The association between PON1(Q192R) polymorphism with clinical predictive CVD biomarkers was assessed using univariate and multivariate logistic regression models. Genotype PON1 (Q192R) frequencies were: 18%, 47% and 35% for QQ, QR, and RR, respectively. Besides, the frequency of the variant R allele was 0.58. Furthermore, robust significant associations were found between PON1 (Q192R) polymorphism with serum ADMA [OR (95% CI); 3.50 (1.20-5.00), p < 0.01]; FABP4 [2.50 (2.15-3.95), p < 0.01]; and miR-126 [1.50 (1.15-2.00), p < 0.01] levels after adjusting for probable confounders. Data found in this research strongly support the notion that proposes a crucial role of PON1 enzyme (Q192R polymorphism) as a genetic determinant in the CVD risk in Mexican women.

Organophosphorus Nerve Agents: Types, Toxicity, and Treatments

Organophosphorus compounds are extensively used worldwide as pesticides which cause great hazards to human health. Nerve agents, a subcategory of the organophosphorus compounds, have been produced and used during wars, and they have also been used in terrorist activities. These compounds possess physiological threats by interacting and inhibiting acetylcholinesterase enzyme which leads to the cholinergic crisis. After a general introduction, this review elucidates the mechanisms underlying cholinergic and noncholinergic effects of organophosphorus compounds. The conceivable treatment strategies for organophosphate poisoning are different types of bioscavengers which include stoichiometric, catalytic, and pseudocatalytic. The current research on the promising treatments specifically the catalytic bioscavengers including several wild-type organophosphate hydrolases such as paraoxonase and phosphotriesterase, phosphotriesterase-like lactonase, methyl parathion hydrolase, organophosphate acid anhydrolase, diisopropyl fluorophosphatase, human triphosphate nucleotidohydrolase, and senescence marker protein has been widely discussed. Organophosphorus compounds are reported to be the nonphysiological substrate for many mammalian organophosphate hydrolysing enzymes; therefore, the efficiency of these enzymes toward these compounds is inadequate. Hence, studies have been conducted to create mutants with an enhanced rate of hydrolysis and high specificity. Several mutants have been created by applying directed molecular evolution and/or targeted mutagenesis, and catalytic efficiency has been characterized. Generally, organophosphorus compounds are chiral in nature. The development of mutant enzymes for providing superior stereoselective degradation of toxic organophosphorus compounds has also been widely accounted for in this review. Existing enzymes have shown limited efficiency; hence, more effective treatment strategies have also been critically analyzed.

Association of Genes Related to Oxidative Stress with the Extent of Coronary Atherosclerosis

Oxidative stress is believed to play a critical role in atherosclerosis initiation and progression. In line with this, in a group of 1099 subjects, we determined eight single nucleotide polymorphisms (SNPs) related to oxidative stress (PON1 c.575A>G, MPO c.−463G>A, SOD2 c.47T>C, GCLM c.−590C>T, NOS3 c.894G>T, NOS3 c.−786T>C, CYBA c.214C>T, and CYBA c.−932A>G) and assessed the extent of atherosclerosis in coronary arteries based on Gensini score. An increased risk of having a Gensini score in the higher half of the distribution was observed for the PON1 c.575G allele (odds ratio (OR) = 1.27, 95% confidence interval (CI): 1.004–1.617, p = 0.046). Next, the genetic risk score (GRS) for the additive effect of the total number of pro-oxidative alleles was assessed. We noted an increase in the risk of having a Gensini score above the median with the maximum number of risk alleles (OR = 2.47, 95% CI: 1.19–5.23, p = 0.014). A univariate Spearman’s test revealed significant correlation between the total number of pro-oxidant alleles (GRS) and the Gensini score (ρ = 0.068, p = 0.03). In conclusion, the PON1 c.575A>G variant and the high number of risk alleles (GRS) were independent risk factors for a high Gensini score. We suggest, however, that GRS might occur as a more valuable component in adding a predictive value to the genetic background of atherosclerosis.

Early Biomarkers of Neurodegenerative and Neurovascular Disorders in Diabetes

Diabetes mellitus (DM) is a common disease worldwide. There is a strong association between DM and neurovascular and neurodegenerative disorders. The first group mainly consists of diabetic retinopathy, diabetic neuropathy and stroke, whereas, the second group includes Alzheimer's disease, Parkinson's disease, mild cognitive impairment and dementia. The aforementioned diseases have a common pathophysiological background including insulin resistance, oxidative stress, atherosclerosis and vascular injury. The increasing prevalence of neurovascular and neurodegenerative disorders among diabetic patients has resulted in an urgent need to develop biomarkers for their prediction and/or early detection. The aim of this review is to present the potential application of the most promising biomarkers of diabetes-related neurodegenerative and neurovascular disorders, including amylin, β-amyloid, C-reactive protein (CRP), dopamine, gamma-glutamyl transferase (GGT), glycogen synthase kinase 3β, homocysteine, microRNAs (mi-RNAs), paraoxonase 1, phosphoinositide 3-kinases, tau protein and various growth factors. The most clinically promising biomarkers of neurovascular and neurodegenerative complications in DM are hsCRP, GGT, homocysteine and miRNAs. However, all biomarkers discussed in this review could become a part of the potential multi-biomarker screening panel for diabetic patients at risk of neurovascular and neurodegenerative complications.

Serum paraoxonase 1 activity in cats: analytical validation, reference intervals, and correlation with serum amyloid A and alpha-1-acid glycoprotein

Paraoxonase 1 (PON1) is an inflammation marker associated with lipid oxidation and is used as a diagnostic marker in people. There is no information about the suitable substrate and analytic performance in cats, or its biological behavior compared with other inflammation markers. Our aims were to validate a paraoxon-based method to measure PON1 activity in feline serum, to assess stability of PON1 under different storage conditions and the impact of interfering elements, to determine a reference interval (RI) for healthy cats, and to correlate PON1 activity with 2 major acute-phase proteins. Intra- and inter-assay precision, accuracy, and RI were assessed using fresh serum. The same specimens were stored at room temperature, refrigerated, or frozen, and retested at defined intervals. Hemolysis, lipemia, and icterus were simulated to study interferences. PON1 results were compared to serum amyloid A (SAA) and alpha-1-acid glycoprotein (AGP) results. Analytical validation yielded precise and accurate results. PON1 activity is stable for up to 24 h at room temperature and up to 48 h at 4°C. Freezing at -20°C results in an increase after 72 h, with return to baseline values after 1 wk, that again increases after 6 mo. Only hyperlipemia interfered with PON1 activity. The RI based on 71 healthy cats was 58-154 U/L. PON1 activity was negatively correlated with AGP, but not with SAA. Serum PON1 activity can be measured accurately in cats, and it acts as a negative acute-phase protein.

Antioxidant Enzymes Haplotypes and Polymorphisms Associated with Obesity in Mexican Children

Obesity is a major health problem worldwide and constitutes a sanitary emergency in Mexico, especially childhood obesity. Several studies have proved the relationship between obesity and oxidative stress and the influence of genetic predisposition. This work was aimed to analyze the association of antioxidant enzyme polymorphisms with overweight and obesity in Mexican children and adolescents. A case-control study was performed in 585 children and adolescents aged 3 to 17 years, using two criteria to classify obesity: body mass index (BMI) and body fat percentage (BFP). Anthropometric and biochemical measurements were carried out, and malondialdehyde serum levels were determined. Genotyping was done with the Axiom Genome-Wide LAT microarray, including 68 single nucleotide polymorphisms (SNPs) of the glutathione peroxidase (GPX) and paraoxonase (PON) families. We found six haplotypes associated with obesity—two of them (one in GPX3 and the other in GPX5 and GPX6) in a protective direction when obesity was classified by BMI. The other four haplotypes were associated with obesity when classification was based on BFP—one of them in GPX3 in a protective direction and the others in PON genes conferring obesity risk. In addition, two SNPs, GPX3 rs922429 and GPX4 rs2074451 showed protection against obesity classified by BFP. This study showed genetic susceptibility to oxidative stress in relation to obesity in Mexican children and opens up the possibility that some genetic loci related to obesity are not identified when weight classification is based on BMI.

Nutrigenetics-personalized nutrition in obesity and cardiovascular diseases

Epidemiological data support the view that both obesity and cardiovascular diseases (CVD) account for a high proportion of total morbidity and mortality in adults throughout the world. Obesity and CVD have complex interplay mechanisms of genetic and environmental factors, including diet. Nutrition is an environmental factor and it has a predominant and recognizable role in health management and in the prevention of obesity and obesity-related diseases, including CVD. However, there is a marked variation in CVD in patients with obesity and the same dietary pattern. The different genetic polymorphisms could explain this variation, which leads to the emergence of the concept of nutrigenetics. Nutritional genomics or nutrigenetics is the science that studies and characterizes gene variants associated with differential response to specific nutrients and relating this variation to various diseases, such as CVD related to obesity. Thus, the personalized nutrition recommendations, based on the knowledge of an individual's genetic background, might improve the outcomes of a specific dietary intervention and represent a new dietary approach to improve health, reducing obesity and CVD. Given these premises, it is intuitive to suppose that the elucidation of diet and gene interactions could support more specific and effective dietary interventions in both obesity and CVD prevention through personalized nutrition based on nutrigenetics. This review aims to briefly summarize the role of the most important genes associated with obesity and CVD and to clarify the knowledge about the relation between nutrition and gene expression and the role of the main nutrition-related genes in obesity and CVD.

Influence of nutritional factors and the PON1 C(-107)T polymorphism on paraoxonase-1 activity in childhood

OBJECTIVE

The cardioprotective enzyme paraoxonase-1 (PON1) suffers an important influence from genetic polymorphisms and nutritional factors. The aim of this study was to investigate the influence of diet, nutritional status, and the C(-107)T polymorphism on PON1 arylesterase activity in children.

METHODS

This was a cross-sectional study with 97 children, aged between 5 and 8 years, of both genders, from a pediatric outpatient clinic in southern Brazil. A sociodemographic, behavioral, and food consumption questionnaire was applied, and anthropometric measurements and laboratory blood samples were taken. PON1 arylesterase activity was measured by phenol extinction (U/mL), and DNA extraction and analysis of the PON1 C(-107)T polymorphism were performed. The Hardy-Weinberg equilibrium was tested with the chi-squared test and linear regression was used to estimate PON1 activity according to four adjustment models, with an acceptable error of 5%.

RESULTS

In the sample, the male gender accounted for 50.5%, 39.2% were 6 years of age, 54.5% had normal weight, and 51.5% had PON1 activity below the median (90.0, 15-30U/mL). Genotype frequency was 54.6% (53/97), 31.0% (30/97), and 14.4% (14/97), respectively, for CT, CC, and TT, consistent with the Hardy-Weinberg equilibrium (p=0.22). In the regression analysis, the model that included sociodemographic variables as well as frequency of consumption of fruits, vegetables, legumes, dairy products, and beans estimated a variability of 14.8% in PON1 activity combined with the PON1 C(-107)T polymorphism.

CONCLUSIONS

During childhood, a good-quality diet with greater inclusion of healthy foods was important to predict the activity of the cardioprotective enzyme PON1 combined with the C(-107)T polymorphism of the PON1 gene.

Bayesian meta-analysis of inter-phenotypic differences in human serum paraoxonase-1 activity for chemical risk assessment

Human variability in paraoxonase-1 (PON1) activities is driven by genetic polymorphisms that affect the internal dose of active oxons of organophosphorus (OP) insecticides. Here, an extensive literature search has been performed to collect human genotypic frequencies (i.e. L55M, Q192R, and C-108T) in subgroups from a range of geographical ancestry and PON1 activities in three probe substrates (paraoxon, diazoxon and phenyl acetate). Bayesian meta-analyses were performed to estimate variability distributions for PON1 activities and PON1-related uncertainty factors (UFs), while integrating quantifiable sources of inter-study, inter-phenotypic and inter-individual differences. Inter-phenotypic differences were quantified using the population with high PON1 activity as the reference group. Results from the meta-analyses provided PON1 variability distributions and these can be implemented in generic physiologically based kinetic models to develop quantitative in vitro in vivo extrapolation models. PON1-related UFs in the Caucasian population were above the default toxicokinetic UF of 3.16 for two specific genotypes namely -108CC using diazoxon as probe substrate and, -108CT, -108TT, 55MM and 192QQ using paraoxon as probe substrate. However, integration of PON1 genotypic frequencies and activity distributions showed that all UFs were within the default toxicokinetic UF. Quantitative inter-individual differences in PON1 activity are important for chemical risk assessment particularly with regards to the potential sensitivity to organophosphates' toxicity.

Deciphering the Role of Polyphenols in Sports Performance: From Nutritional Genomics to the Gut Microbiota toward Phytonutritional Epigenomics

The individual response to nutrients and non-nutrient molecules can be largely affected by three important biological layers. The gut microbiome can alter the bioavailability of nutrients and other substances, the genome can influence molecule kinetics and dynamics, while the epigenome can modulate or amplify the properties of the genome. Today the use of omic techniques and bioinformatics, allow the construction of individual multilayer networks and thus the identification of personalized strategies that have recently been considered in all medical fields, including sports medicine. The composition of each athlete’s microbiome influences sports performance both directly by acting on energy metabolism and indirectly through the modulation of nutrient or non-nutrient molecule availability that ultimately affects the individual epigenome and the genome. Among non-nutrient molecules polyphenols can potentiate physical performances through different epigenetic mechanisms. Polyphenols interact with the gut microbiota, undergoing extensive metabolism to produce bioactive molecules, which act on transcription factors involved in mitochondrial biogenesis, antioxidant systems, glucose and lipid homeostasis, and DNA repair. This review focuses on polyphenols effects in sports performance considering the individual microbiota, epigenomic asset, and the genomic characteristics of athletes to understand how their supplementation could potentially help to modulate muscle inflammation and improve recovery.

Paraoxonase 1 and atherosclerosis-related diseases

A direct and an indirect relationship between paraoxonase 1 (PON1) and atherosclerosis exists. Given PON1's physical location within high-density lipoprotein (HDL) particles and its recognized enzyme activity, it is certainly reasonable to suggest that PON1 facilitates the antiatherogenic nature of HDL particles. PON1 also plays a role in regulating reverse cholesterol transport, antioxidative, anti-inflammatory, antiapoptotic, vasodilative, and antithrombotic activities and several endothelial cell functions. HDL dysfunctionality is a more recent issue and seems to be centered on pathological conditions affecting HDL structure and size profiles. This review is focused on the role of PON1 status in different atherosclerosis-related diseases that we have studied over the last twenty years (coronary heart disease, acute ischemic stroke, diabetes mellitus type 2, end-stage renal disease, chronic obstructive pulmonary disease, and sarcoidosis) with the aim to determine the true value of PON1 as a biomarker. The role of PON1 in cancer is also covered, as risk factors and mechanisms underlying both atherosclerosis and cancer share common features.

Plasma paraoxonase1 activity in rats treated with monocrotophos: a study of the effect of duration of exposure

We have earlier demonstrated the potential of monocrotophos (MCP), a highly toxic organophosphorus insecticide (OPI), to elicit insulin resistance in rats after chronic exposure. Given the understanding of role of paraoxonase1 (PON1) in OPI toxicity and diabetes pathology, this study was envisaged to understand the effect of duration of exposure to MCP on plasma PON1 activity in rats. Rats were administered MCP per os at 1/20 and 1/10^th LD₅₀ as daily doses for 180 days. Interim blood samples were collected at 15, 30, 45, 90 and 180 d for analysis of plasma parameters. Exposure to MCP for 45 resulted in persistent trend of hyperinsulinemia, while significant increase in fasting glucose levels was observed after 180 days. MCP caused suppression of plasma cholinesterase activity though the study period, albeit extent of inhibition was more severe during the early phase of the study. Exposure to MCP for 180 d resulted in hypertriglyceridemia and marginal decrease in HDL-C levels. MCP failed to modulate PON1 activity in plasma during the early phase of the study (up to 45 d). However, prolonged exposure resulted in significant increase in the plasma PON1 activity. This suggests that manifestation of insulin resistance in rats subjected to chronic exposure to MCP is associated with increase in PON1 activity. Our work provides rationale for studying whether the increase in PON1 activity observed in the present study serves to counter the deleterious effect of long term exposure to organophosphorus insecticides on metabolic homeostasis.

Frontocingulate Dysfunction Is Associated with Depression and Decreased Serum PON1 in Methamphetamine-Dependent Patients

INTRODUCTION

Studies have been reported that frequent use of methamphetamine (MA) is associated with brain function impairment, mood disorders and excessive free radical production accompanied by the decreased level of the antioxidant response elements, but no study investigated their correlations simultaneously. In the current study, the correlation of brain function, depression and anxiety levels, and the serum levels of PON1 (an antioxidant) in MA-dependent patients were investigated.

METHODS

Nineteen active MA abusers and 18 control subjects performed color-word Stroop task during fMRI and the state of their depression, anxiety, and stress were measured by the Depression, Anxiety and Stress Scale-21 Items (DASS-21) questionnaire. Their blood samples were collected to measure the level of PON1 by the human enzyme-linked immunosorbent assay (ELISA) kit and its correlation with the measured variables was studied.

RESULTS

Analysis of fMRI findings showed frontocingulate dysfunction in Stroop effect condition, including left anterior cingulate cortex, paracingulate gyrus, superior frontal gyrus, and frontal pole in MA-dependent patients, which was associated with a higher level of depression and decreased level of serum PON1 in these patients.

DISCUSSION

The results of the current study showed that MA-dependency is associated with frontocingulate dysfunction, decreased serum PON1 concentration, and increased depression/anxiety, which is worth to be more studied to elucidate their roles in the pathophysiology of MA addiction.

Paraoxonase-1 Serum Concentration and PON1 Gene Polymorphisms: Relationship with Non-Alcoholic Fatty Liver Disease

Background: Non-alcoholic fatty liver disease (NAFLD) is an important cause of chronic liver diseases around the world. Paraoxonase-1 (PON1) is an enzyme produced by the liver with an important antioxidant role. The aim of this study was to evaluate PON1 serum concentration and PON1 gene polymorphisms in patients with NAFLD. Materials and methods: We studied a group of 81 patients with NAFLD with persistently elevated aminotransferases and a control group of 81 patients without liver diseases. We collected clinical information and performed routine blood tests. We also measured the serum concentration of PON1 and evaluated the PON1 gene polymorphisms L55M, Q192R, and C-108T. Results: There was a significant difference (p < 0.001) in serum PON1 concentrations among the two groups. The heterozygous and the mutated homozygous variants (LM + MM) of the L55M polymorphism were more frequent in the NAFLD group (p < 0.001). These genotypes were found in a multivariate binary logistic regression to be independently linked to NAFLD (Odds ratio = 3.4; p = 0.04). In a multivariate linear regression model, the presence of NAFLD was associated with low PON1 concentration (p < 0.001). Conclusions: PON1 serum concentrations were diminished in patients with NAFLD, and the presence of NAFLD was linked with low PON1 concentration. The LM + MM genotypes of the PON1 L55M polymorphism were an independent predictor for NAFLD with persistently elevated aminotransferases.

A meta-analysis of the relationship between paraoxonase 1 polymorphisms and cancer

Some previous studies already explored associations between paraoxonase 1 (PON1) polymorphisms and cancer, with conflicting findings. Here, we aimed to better analyse the relationship between PON1 polymorphisms and cancer in a larger combined population by performing a meta-analysis. We searched PubMed, Embase, and Web of Science for related articles. We calculated odds ratio (OR) and 95% confidence interval (CI) to estimate whether there are genetic associations between PON1 polymorphisms and cancer. Forty studies were included for this meta-analysis. The PON1 rs854560 polymorphism (L55M) was found to be significantly associated with cancer in general population (dominant comparison: p = .04, OR = 0.85, 95%CI 0.73-0.99; recessive comparison: p = .007, OR = 1.27, 95%CI 1.07-1.51; allele comparison: p = 0.02, OR = 0.85, 95%CI 0.75-0.97). Subgroup analyses indicated that the significant findings were mainly driven by the haematological tumours and breast cancer subgroups. We did not observe any positive findings for PON1 rs662 polymorphism (Q192R) in combined analyses. In summary, this meta-analysis proved that PON1 rs854560 polymorphism could be used to identify individual with elevated susceptibility to cancer, especially for haematological tumours and breast cancer.

Low Serum Paraoxonase-1 Activity Associates with Incident Cardiovascular Disease Risk in Subjects with Concurrently High Levels of High-Density Lipoprotein Cholesterol and C-Reactive Protein

Paroxonase-1 (PON1) is a key enzyme that inhibits low-density lipoprotein oxidation and consequently atherogenesis. Here, we assessed whether low serum PON1 activity associates with incident cardiovascular disease (CVD) in subjects with high levels of high-density cholesterol (HDL-C) and C-reactive protein (CRP), a marker of low-grade systemic inflammation. Cox proportional-hazards modeling of incident CVD risk (11 years mean follow-up) adjusted for relevant clinical and biomarker covariates was performed on a population-based study (N = 7766) stratified into three groups: low CRP-(LR; event rate 4.9%); low HDL-C/high CRP-(HR1; event rate 14.4%); and high HDL-C/high CRP-(HR2; event rate 7.6%). Modeling results for PON1 activity in HR2 were significant and robust (hazard ratio/SD unit-0.68, 95% CI 0.55-0.83, p = 0.0003), but not so for LR and HR1. Analyses in HR2 of the interaction of PON1 with HDL-C, apoA-I, apoA-II, and apoE levels were significant only for PON1 with apoE (hazard ratio-1.77, 95% CI 1.29-2.41, p = 0.0003). Subsequent subgroup analysis revealed inverse risk dependence for apoE at low PON1 levels. In conclusion, in a population-based study of subjects with concurrently high HDL-C and CRP levels, low serum PON1 activity associates with incident CVD risk with risk accentuated at low apoE levels.

A meta-analysis on relationship between paraoxonase 1 polymorphisms and atherosclerotic cardiovascular diseases

BACKGROUND

Some previous studies already explored associations between paraoxonase 1 (PON1) polymorphisms and atherosclerotic cardiovascular diseases (ASCVD), with conflicting findings. Here, we aimed to better analyze the relationship between PON1 polymorphisms and ASCVD in a larger combined population by performing a meta-analysis.

METHODS

We searched Pubmed, Embase and Web of Science for related articles. We calculated odds ratio (OR) and 95% confidence interval (CI) to estimate whether there are genetic associations between PON1 polymorphisms and ASCVD.

RESULTS

One hundred and nine studies were included for this meta-analysis. The PON1 rs854560 (17,220 cases and 18,570 controls, recessive comparison: OR = 0.83, 95%CI 0.72-0.96) and rs662 (30,717 cases and 54,894 controls, dominant comparison: OR = 0.82, 95% CI 0.77-0.89; recessive comparison: OR = 1.17, 95% CI 1.07-1.28; allele comparison: OR = 0.85, 95% CI 0.81-0.90) polymorphisms were both found to be significantly associated with susceptibility to ASCVD in general population. Subgroup analyses by ethnicity revealed similar significant findings for rs854560 polymorphism only in East Asians, while similar positive findings for rs662 polymorphism were observed in Caucasians, East Asians and South Asians. Subgroup analyses by type of disease indicated that the significant findings for rs854560 polymorphism were mainly driven by the ischemic stroke (IS) subgroup, whereas the positive results for rs662 polymorphism were mainly driven by the coronary artery disease (CAD) subgroup.

CONCLUSIONS

In summary, this meta-analysis proved that PON1 rs854560 polymorphism could be used to identify individual with elevated susceptibility to IS, whereas rs662 polymorphism could be used to identify individual with elevated susceptibility to CAD.

Association of PON2 and PON3 polymorphism with risk of developing cataract

Purpose

Paraoxonases (PON) are calcium bound enzymes offering protection against oxidative stress by working as endogenous free-radical scavenging molecules. Oxidative stress has been implicated in pathophysiology of many diseases including cataract. Lens opacity is an age related disorder which is a principal cause of blindness in Pakistani population. Relationship of PON2 and PON3 polymorphism with genetic predisposition for incidence of cataract has not been investigated till date. Objective of the current study was to explore possible association between PON2 and PON3 polymorphism with incidence of cataract in local population.

Methods

Our study design comprised of fifty-one cataractous and fifty-nine healthy individuals. Identification of single nucleotide polymorphism (SNP) at positions (C311S and G148A) for PON2 and C133A for PON3 was conducted using restriction fragment length polymorphism (RFLP).

Results

Statistical analysis revealed significant association of PON2 G148 allele with incidence of cataract. GG allele was found to be higher in cataract patients as compared to control (p < 0.001) suggesting distribution of PON2 G148A genotype and allele frequency is linked with cataractogenesis. There was no noticeable association between PON2 C311S and PON3 C133A. Significant difference was observed in distribution of 311CS/148A combined genotype with highest frequency in control individuals (88.89%), while 311S/148G combined genotypes showed the highest frequencies among the cataract patients (71.42%).

Conclusion

Our data suggests mutation at G148A might be related with incidence of cataract in studied population.

Paraoxonases Activities and Polymorphisms in Elderly and Old-Age Diseases: An Overview

Aging is defined as the accumulation of progressive organ dysfunction. There is much evidence linking the involvement of oxidative stress in the pathogenesis of aging. With increasing age, susceptibility to the development of diseases related to lipid peroxidation and tissue injury increases, due to chronic inflammatory processes, and production of reactive oxygen species (ROS) and free radicals. The paraoxonase (PON) gene family is composed of three members (PON1, PON2, PON3) that share considerable structural homology and are located adjacently on chromosome 7 in humans. The most studied member product is PON1, a protein associated with high-density lipoprotein with paraoxonase/esterase activity. Nevertheless, all the three proteins prevent oxidative stress. The major aim of this review is to highlight the importance of the role of PON enzymes in the aging process, and in the development of the main diseases present in the elderly: cardiovascular disease, diabetes mellitus, neurodegenerative diseases, and cancer.

Is Human Paraoxonase 1 the Saviour Against the Persistent Threat of Organophosphorus Nerve Agents?

Nerve agents have been used extensively in chemical warfare in the past. However, recent use of Novichok agents have reignited the debate on the threat posed by Organophosphorus Nerve Agents (OPNAs). The currently available therapy for OPNA toxicity is only symptomatic and is potentially ineffective in neutralizing OPNAs. Hence, there is a dire need to develop a prophylactic therapy for counteracting OPNA toxicity. In this regard, human paraoxonase 1 has emerged as the enzyme of choice. In this review, we have focussed upon the recent and past events of OPNA use, their mechanism of action and toxicity. Further, we have emphasized upon the potential of enzyme based therapy and the various advances in the development of paraoxonase 1 as a countermeasure for OPNA poisoning. Finally, we have elaborated the shortcomings of paraoxonase 1 and the work that needs to be undertaken in order to develop human paraoxonase 1 as a prophylactic against OPNA poisoning.

Evaluation of Paraoxonase, Arylesterase, and Homocysteine Thiolactonase Activities in Patients with Diabetes and Incipient Diabetes Nephropathy

Background

The aim of this study is to examine the relationship among the changes in activities of paraoxonase (PON), arylesterase (ARE) and homocysteine thiolactonase (HTLase) enzyme having antioxidant properties and the development of diabetic nephropathy (DN), one of the most common complications of diabetes.

Methods

Normoalbuminuric type-2 diabetic patients (Group II, n=100), microalbuminuric type 2 diabetic patients (Group III, n=100) and the control group (Group I, n=100) were included in the study. The age and gender of the patient groups matched with the age and gender of the control group. HTLase, PON and ARE enzyme activities were measured by the spectrophotometric method using a g-thiobutyrinolactone, paraoxon, and phenylacetate substrates respectively. In this study, an autoanalyzer application was developed in order to measure HTLase enzyme activity for the first time.

Results

Serum HTLase, ARE and PON activities of Group III and Group II were significantly low compared to HTLase, ARE and PON results of Group I (p<0.05).

Conclusions

Based on our results, PON, ARE and HTLase enzyme activities were found to be decreased due to the increase in the degree of DN.

Epistasis between ADIPOQ rs1501299 and PON1 rs662 polymorphisms is potentially associated with the development of knee osteoarthritis

Overweight produces oxidative stress (OS) on the articular cartilage, with the subsequent risk of developing knee osteoarthritis (OA). Associations between genetic polymorphisms related to OS and OA have been reported, but it is currently unknown whether there exist interactions among them that affect OA development. To identify and evaluate interactions between multiple SNPs related to OS in Mexican knee OA patients. Ninety-two knee OA patients were included in the study, which were compared to 147 healthy controls. Nine variants of six genes (PEPD, AGER, IL6, ADIPOQ, PON1, and CA6) related to OS were genotyped in both study groups through the OpenArray system. Epistasis was analyzed with the multifactor dimensionality reduction (MDR) method. The MDR analysis revealed a significant interaction (p = 0.0107) between polymorphisms rs1501299 (ADIPOQ) and rs662 (PON1), with an entropy value of 9.84%; in addition, high and low risk genotypes were identified between these two polymorphisms. The effect of the interaction between rs1501299 (ADIPOQ) and rs662 (PON1) polymorphisms seems to play an important role in OA pathogenesis; so the epistasis analysis may provide an excellent tool for identifying individuals at high risk for developing OA.