Mice lacking serum paraoxonase are susceptible to organophosphate toxicity and atherosclerosis

Association of SNPs in Lipid Metabolism Gene Single Nucleotide Polymorphism with the Risk of Obesity in Children

Background: Obesity is one of the most common metabolic disorders in the world, which develops due to an imbalance in energy consumption and expenditure, and both genetic and environmental factors are of great importance. We investigated the potential interactions of single nucleotide polymorphisms that might contribute to the development of polygenic obesity in children. Objective: The study involved 367 children and adolescents of both sexes aged from 4 to 18 years. The control group (normal weight) and the overweight groups included 65 and 302 children respectively. Methods: DNA for analysis was isolated from peripheral blood lymphocytes, then allelic variants rs99305069 of the FTO gene (chr16:53786615), Gln192Arg of the PON1 gene (chr7: 95308134), -250G>A of the LIPC gene (chr15: 58431740), and Ser447Ter of the LPL gene (chr8:19957678) were studied using the SNP-Express reagent kit. The results of allelic interactions were analyzed using the multifactor dimensionality reduction method. Results and Discussion: Among overweight children, the distribution of genotype and allele frequencies for the studied single nucleotide polymorphisms of the four genes corresponded to those of the control group (p > 0.05). It was found that in obese children SerSer homozygotes at the Ser447Ter polymorphism of the LPL gene, had serum triglyceride (TG) levels 2.3 times higher than in children with the same genotype from the control group. In overweight Ser447Ter heterozygotes (p < 0.0001), the TG level exceeded the control values by only 13% (p = 0.044). A two-locus genotype FTO AT/LPL SerTer, was associated with a reduced risk of childhood obesity.

DING Proteins Extend to the Extremophilic World

The DING proteins are ubiquitous in the three domains of life, from mesophiles to thermo- and hyperthermophiles. They belong to a family of more than sixty members and have a characteristic N-terminus, DINGGG, which is considered a "signature" of these proteins. Structurally, they share a highly conserved phosphate binding site, and a three dimensional organization resembling the "Venus Flytrap", both reminding the ones of PstS proteins. They have unusually high sequence conservation, even between distantly related species. Nevertheless despite that the genomes of most of these species have been sequenced, the DING gene has not been reported for all the relative characterized DING proteins. Identity of known DING proteins has been confirmed immunologically and, in some cases, by N-terminal sequence analysis. Only a few of the DING proteins have been purified and biochemically characterized. DING proteins are heterogeneous for their wide range of biological activities and some show different activities not always correlated with each other. Most of them have been originally identified for different biological properties, or rather for binding to phosphate and also to other ligands. Their involvement in pathologies is described. This review is an update of the most recent findings on old and new DING proteins.

Polymorphisms in genes involved in breast cancer among Iranian patients

This review gives a summary of the important genetic polymorphisms in breast cancer with a focus on people in Iran. Several single nucleotide polymorphisms were considered as breast cancer susceptibility polymorphisms within genes (STK15, ERRs, ESR1, p53, SEP15, AURKA, SHBG, SRC, FAS, VEGF, XRCC1, GST, NFκB1, XPC, XRCC3, sirtuin-3, NKG2D). Cytosine-adenine repeat (IGF-I), rs3877899, G-2548A, GGC (eRF3a/GSPT1), IVS2nt-124A/G have shown an increased risk of breast cancers and a decreased risk has been observed in 4G/5G (PAI-1), rs6505162, tri-nucleotide (GCG TGFBR1). We observed that the signaling pathways and antioxidant related genes are the main molecular processes associated with breast cancer progression. Further studies on types of polymorphisms in breast cancer could validate the prognostic value of biomarkers.

Dissecting lipid metabolism alterations in SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of the COVID-19 pandemic that has infected over a hundred million people globally. There have been more than two million deaths recorded worldwide, with no end in sight until a widespread vaccination will be achieved. Current research has centred on different aspects of the virus interaction with cell surface receptors, but more needs to be done to further understand its mechanism of action in order to develop a targeted therapy and a method to control the spread of the virus. Lipids play a crucial role throughout the viral life cycle, and viruses are known to exploit lipid signalling and synthesis to affect host cell lipidome. Emerging studies using untargeted metabolomic and lipidomic approaches are providing new insight into the host response to COVID-19 infection. Indeed, metabolomic and lipidomic approaches have identified numerous circulating lipids that directly correlate to the severity of the disease, making lipid metabolism a potential therapeutic target. Circulating lipids play a key function in the pathogenesis of the virus and exert an inflammatory response. A better knowledge of lipid metabolism in the host-pathogen interaction will provide valuable insights into viral pathogenesis and to the development of novel therapeutic targets.

Role of Paraoxonase1 in the Regulation of High-Density Lipoprotein Functionality and in Cardiovascular Protection

Significance: Human paraoxonase (PON) is a member of the gene family that includes paraoxonase 1 (PON1), PON2, and PON3. PON is known for its capacity to hydrolyze a wide range of substrates, including organophosphorus compounds, nerve gases, and aromatic carboxylic acid esters. Recent Advances: Several studies have highlighted the involvement of PON, particularly PON1, in the modulation of the capacity of high-density lipoprotein (HDL) to protect against the atherosclerosis process and its clinical manifestations. PON1 exhibits antioxidant and anti-inflammatory activities and may be involved in the regulation of the principal antiatherogenic activity of HDL, that is, the regulation of the reverse cholesterol transport process. Critical Issues: Although epidemiological studies have shown that there is an inverse relationship between HDL levels and cardiovascular risk, several studies have emphasized the importance of HDL functionality in protecting against cardiovascular diseases (CVD). Given that PON1 is involved in several atheroprotective functions of HDL, the aim of this article is to review the existing literature on PON1 and to discuss the principal mechanisms by which PON1 may exert its different activities. Future Directions: The elucidation of the mechanisms by which PON1 modulates the functionality of HDL as well as the identification of the interventions that stimulate PON1 activity and/or increase its plasma concentration would make it possible to propose new strategies to prevent CVD. Antioxid. Redox Signal. 34, 191-200.

Endothelial Lipase Modulates Paraoxonase 1 Content and Arylesterase Activity of HDL

Endothelial lipase (EL) is a strong modulator of the high-density lipoprotein (HDL) structure, composition, and function. Here, we examined the impact of EL on HDL paraoxonase 1 (PON1) content and arylesterase (AE) activity in vitro and in vivo. The incubation of HDL with EL-overexpressing HepG2 cells decreased HDL size, PON1 content, and AE activity. The EL modification of HDL did not diminish the capacity of HDL to associate with PON1 when EL-modified HDL was incubated with PON1-overexpressing cells. The overexpression of EL in mice significantly decreased HDL serum levels but unexpectedly increased HDL PON1 content and HDL AE activity. Enzymatically inactive EL had no effect on the PON1 content of HDL in mice. In healthy subjects, EL serum levels were not significantly correlated with HDL levels. However, HDL PON1 content was positively associated with EL serum levels. The EL-induced changes in the HDL-lipid composition were not linked to the HDL PON1 content. We conclude that primarily, the interaction of enzymatically active EL with HDL, rather than EL-induced alterations in HDL size and composition, causes PON1 displacement from HDL in vitro. In vivo, the EL-mediated reduction of HDL serum levels and the consequently increased PON1-to-HDL ratio in serum increase HDL PON1 content and AE activity in mice. In humans, additional mechanisms appear to underlie the association of EL serum levels and HDL PON1 content.

The Structure and Function of Paraoxonase-1 and Its Comparison to Paraoxonase-2 and -3

Serum paraoxonase-1 (PON1) is the most studied member of the group of paraoxonases (PONs). This enzyme possesses three enzymatic activities: lactonase, arylesterase, and paraoxonase activity. PON1 and its isoforms play an important role in drug metabolism as well as in the prevention of cardiovascular and neurodegenerative diseases. Although all three members of the PON family have the same origin and very similar amino acid sequences, they have different functions and are found in different locations. PONs exhibit substrate promiscuity, and their true physiological substrates are still not known. However, possible substrates include homocysteine thiolactone, an analogue of natural quorum-sensing molecules, and the recently discovered derivatives of arachidonic acid—bioactive δ-lactones. Directed evolution, site-directed mutagenesis, and kinetic studies provide comprehensive insights into the active site and catalytic mechanism of PON1. However, there is still a whole world of mystery waiting to be discovered, which would elucidate the substrate promiscuity of a group of enzymes that are so similar in their evolution and sequence yet so distinct in their function.

High-Density Lipoprotein-Targeted Therapies for Heart Failure

The main and common constituents of high-density lipoproteins (HDLs) are apolipoprotein A-I, cholesterol, and phospholipids. Biochemical heterogeneity of HDL particles is based on the variable presence of one or more representatives of at least 180 proteins, 200 lipid species, and 20 micro RNAs. HDLs are circulating multimolecular platforms that perform divergent functions whereby the potential of HDL-targeted interventions for treatment of heart failure can be postulated based on its pleiotropic effects. Several murine studies have shown that HDLs exert effects on the myocardium, which are completely independent of any impact on coronary arteries. Overall, HDL-targeted therapies exert a direct positive lusitropic effect on the myocardium, inhibit the development of cardiac hypertrophy, suppress interstitial and perivascular myocardial fibrosis, increase capillary density in the myocardium, and prevent the occurrence of heart failure. In four distinct murine models, HDL-targeted interventions were shown to be a successful treatment for both pre-existing heart failure with reduced ejection fraction (HFrEF) and pre-existing heart failure with preserved ejection fraction (HFrEF). Until now, the effect of HDL-targeted interventions has not been evaluated in randomized clinical trials in heart failure patients. As HFpEF represents an important unmet therapeutic need, this is likely the preferred therapeutic domain for clinical translation.

Analysis of PON1 gene polymorphisms (rs662 and rs854560) and inflammatory markers in organophosphate pesticides exposed cohorts from two distinct populations

BACKGROUND AND OBJECTIVES

Organophosphate (OPs) anticholinesterases are one of the main groups of pesticides used in agriculture. Harmful effects of OPs on health have been attributed primarily for irreversible inhibition of acetylcholinesterase (AChE) at nerve synapse. However, studies have shown that inhibition of AChE alone cannot explain all the maladies encountered in prolonged exposure to OPs. Predisposition to population heterogeneity and irregularities in various biochemicals like paraoxonases and inflammatory biochemicals are the possible affects of OPs long term exposure that may lead to sequels of diseases and are less addressed in literature. The study was aimed to assess the cholinergic enzymes (AChE and BChE), PON1, and inflammatory markers (IL1β, IL6, TNFα, CRP, Apo AI, Apo B) and determine the toxicogenetics association of PON1 gene (rs 662 and rs 85456) to chronically OPs exposed groups from Pakistan and Cameroon.

MATERIALS AND METHODS

AChE, BChE and PON1 were measured by colorimetric method using spectrophotometry. Inflammatory markers were determined by Elisa assay. PCR-restriction fragment length polymorphism (PCR-RFLP) using salting out method was employed for SNP genotyping.

RESULTS

The results revealed the significant (p ≤ 0.05) inhibition of cholinergic enzymes PON 1 was found to be 6.91 ng/mL±1.03 and 2.84 ng/mL±1.40 (mean ± SD) in Pakistan and Cameroon groups respectively. IL6, TNFα, CRP were increased and Apo AI was less while Apo B was increased in OP exposed groups in both population groups. SNPs analysis of PON1 showed significant differences in allelic and genotype frequencies of OPs exposed and non-exposed groups.

CONCLUSIONS

PON1 was noticeably less in Cameroonian than Pakistani, albeit both groups have significant decrease in PON1 actity. In addition, the study concludes that OPs induce low grade inflammation, an aetiology of many diseases. Selected PON1 SNPs analysis showed a significant toxicogenetics association with OPs exposure marker enzymes. The results of this study may help in regulation of usage of OPs anticholinesterases in different populations. The study will further open new avenues in toxicogenetic and exploration of SNPs based strategies on organophosphate intoxication.

Genetic Attenuation of Paraoxonase 1 Activity Induces Proatherogenic Changes in Plasma Proteomes of Mice and Humans

High-density lipoprotein (HDL), in addition to promoting reverse cholesterol transport, possesses anti-inflammatory, antioxidative, and antithrombotic activities. Paraoxonase 1 (PON1), carried on HDL in the blood, can contribute to these antiatherogenic activities. The PON1-Q192R polymorphism involves a change from glutamine (Q variant) to arginine (R variant) at position 192 of the PON1 protein and affects its enzymatic activity. The molecular basis of PON1 association with cardiovascular and neurological diseases is not fully understood. To get insight into the function of PON1 in human disease, we examined how genetic attenuation of PON1 levels/activity affect plasma proteomes of mice and humans. Healthy participants (48.9 years old, 50% women) were randomly recruited from the Poznań population. Four-month-old Pon1^−/− (n = 17) and Pon1^+/+ (n = 8) mice (50% female) were used in these experiments. Plasma proteomes were analyzed using label-free mass spectrometry. Bioinformatics analysis was carried out using the Ingenuity Pathway Analysis (IPA) resources. PON1-Q192R polymorphism and Pon1^−/− genotype induced similar changes in plasma proteomes of humans and mice, respectively. The top molecular network, identified by IPA, affected by these changes involved proteins participating in lipoprotein metabolism. Other PON1 genotype-dependent proteomic changes affect different biological networks in humans and mice: “cardiovascular, neurological disease, organismal injury/abnormalities” in PON1-192QQ humans and “humoral immune response, inflammatory response, protein synthesis” and “cell-to-cell signaling/interaction, hematological system development/function, immune cell trafficking” in Pon1^−/− mice. Our findings suggest that PON1 interacts with molecular pathways involved in lipoprotein metabolism, acute/inflammatory response, and complement/blood coagulation that are essential for blood homeostasis. Modulation of those interactions by the PON1 genotype can account for its association with cardiovascular and neurological diseases.

Serial measurements of Paraoxonase-1 (PON-1) activity in horses with experimentally induced endotoxemia

Background

Paraoxonase-1 (PON-1) is an antioxidant enzyme, whose activity decreases during the acute phase response in many species. Little is known about PON-1 and its role as a negative acute phase protein during septic inflammation in horses, but promising findings about its utility in diagnosing SIRS and predicting the outcome in diseased horses, were recently highlighted. The objective of the study was to investigate the behaviour of PON-1 in horses after experimentally induced endotoxemia. To this aim, PON-1 activity was measured on 66 plasma samples collected from six clinically healthy mares, previously included in another study, before and at multiple time points between 12 and 240 h after intravenous infusion of Escherichia coli O55:B5 lipopolysaccharide (LPS).

Results

Compared with baseline values, a progressive transient decrease of PON-1 activity was observed starting from 24 h post-infusion, with lowest values observed between 3 to 7 days post-infusion, followed by a normalisation to pre-infusion levels the tenth day.

Conclusions

The results of this study suggest that measurement and monitoring of PON-1 activity might be useful to evaluate progression and recovery from endotoxemia in horses. Further studies in horses with naturally occurring sepsis are warranted.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-020-02629-4.

Simultaneous Cross-Linking and Cross-Polymerization of Enzyme Responsive Polyethylene Glycol Nanogels in Confined Aqueous Droplets for Reduction of Low-Density Lipoprotein Oxidation

A key initiating step in atherosclerosis is the accumulation and retention of apolipoprotein B complexing lipoproteins within the artery walls. In this work, we address this exact initiating mechanism of atherosclerosis, which results from the oxidation of low-density lipoproteins (oxLDL) using therapeutic nanogels. We present the development of biocompatible polyethylene glycol (PEG) cross-linked nanogels formed from a single simultaneous cross-linking and co-polymerization step in water without the requirement for an organic solvent, high temperature, or shear stress. The nanogel synthesis also incorporates in situ noncovalent electrostatically driven template polymerization around an innate anti-inflammatory and anti-oxidizing paraoxonase-1 (PON-1) enzyme payload-the release of which is triggered because of matrix metalloproteinase responsive elements instilled in the PEG cross-linker monomer. The results obtained demonstrate the potential of triggered release of the PON-1 enzyme and its efficacy against the production of ox-LDL, and therefore a reduction in macrophage foam cell and reactive oxygen species formation.

Suppression of inflammatory arthritis in human serum paraoxonase 1 transgenic mice

Paraoxonase 1(PON1) is an HDL-associated protein, which metabolizes inflammatory, oxidized lipids associated with atherosclerotic plaque development. Because oxidized lipid mediators have also been implicated in the pathogenesis of rheumatoid arthritis (RA), we evaluated the role of PON1 in murine inflammatory arthritis. K/BxN serum transfer (STIA) or collagen antibody transfer (CAIA) was used for arthritis induction in B6 mice homozygous for the PON1 human transgene [PON1Tg], PON1 knock-out mice [PON1KO], and wild type littermate control mice [WT]. Experiments were also performed in K/BxN mice with chronic arthritis, and in RA patients and healthy controls. Arthritis activity in K/BxN mice was associated with a marked dyslipidemia, lower PON1 activity and higher bioactive lipid mediators (BLM), as well as a dysregulated hepatic lipid gene expression profile. Higher serum PON1 activity correlated with lower BLM and lower arthritis activity in both K/BxN mice and RA patients. Overexpression of the human PON1 transgene was associated with reduced inflammatory arthritis, which correlated strongly with higher circulating PON1 activity, upregulation of the hepatic glutathione pathway, and reduction of circulating BLM. These results implicate PON1 as a potential novel therapeutic target for joint disease in RA with potential for vascular benefit, which warrants further investigation.

Developmental and social deficits and enhanced sensitivity to prenatal chlorpyrifos in PON1-/- mouse pups and adults

The levels and activity of the enzyme paraoxonase 1 affect the vulnerability to the teratogenic effects of organophosphate pesticides. Mutant mice lacking the gene for paraoxonase1 (PON1^-/-) are more susceptible to the toxic effects of chlorpyrifos, and were hypothesized to be more vulnerable to social behavior deficits induced by exposure to chlorpyrifos during gestation. Three experiments were performed comparing PON1^-/- mice to PON1^+/+ mice born to dams treated with 0.5 mg/kg chlorpyrifos or cornoil vehicle on gestational days 12–15. Chlofpyrifos-exposed male PON1^-/- mouse pups had delayed development of reflexes in in the first experiment. In the second experiment, adult male and female PON1^-/- mice and the female PON1^+/+ mice all displayed lower social preference than the male vehicle-treated PON1^+/+ mice. The PON1^-/- mice and the female PON1^+/+ mice displayed lower social preference compared to the PON1^+/+ male mice. Male adult mice that had been exposed in utero to chlorpyrifos showed less conditioned social preference regardless of genotype. In the third study, the delayed reflex development was replicated in male and female PON1^-/- mice, but chlorpyrifos did not augment this effect. Nest Odor Preference, a test of early social attachment to dam and siblings, was lower in PON1^-/- mouse pups compared to PON1^+/+ pups. This study shows for the first time that PON1^-/- mice have a behavioral phenotype that indicates impaired reflex development and social behavior. Chlorpyrifos exposure during gestation tended to augment some of these effects.

Paraoxonase 1 Phenotype and Protein N-Homocysteinylation in Patients with Rheumatoid Arthritis: Implications for Cardiovascular Disease

Paraoxonase 1 (PON1) is the high density lipoprotein-associated esterase which inhibits the development of atherosclerosis by metabolizing lipid peroxidation products as well as hydrolyzing proatherogenic metabolite of homocysteine (Hcy), Hcy thiolactone, which otherwise reacts with lysine groups of proteins, thus forming N-Hcy-protein in a process referred to as protein N-homocysteinylation. Rheumatoid arthritis (RA) is the chronic inflammatory autoimmune disease associated with increased risk of cardiovascular complications, but the underlying mechanisms are incompletely understood. We examined PON1 status and N-homocysteinylation of serum proteins in patients with RA. Blood was collected from 74 RA patients and 70 control subjects. PON1 activity was measured toward synthetic (paraoxon, phenyl acetate) and natural (Hcy thiolactone) substrates. PON1 protein concentration was measured by ELISA. Total Hcy as well as N-Hcy-protein were measured in serum as well. PON1 activity toward Hcy thiolactone was lower in RA patients than in control subjects which was accompanied by increased concentration of N-Hcy-protein despite normal total Hcy concentration. PON1 protein concentration was unchanged in the RA group, but the specific enzyme activity was reduced. When RA patients were categorized according to the DAS28-ESR score, PON1 concentration and enzymatic activity were lower whereas N-Hcy-protein was higher in those with high disease activity. PON1 activity and Hcy thiolactone were correlated with DAS28-ESR score and myeloperoxidase concentration. In conclusion, RA is associated with deficiency of PON1 activity and increased protein N-homocyseinylation which may contribute to accelerated development of cardiovascular diseases.

Lipoproteins and lipids in cardiovascular disease: from mechanistic insights to therapeutic targeting

With cardiovascular disease being the leading cause of morbidity and mortality worldwide, effective and cost-efficient therapies to reduce cardiovascular risk are highly needed. Lipids and lipoprotein particles crucially contribute to atherosclerosis as underlying pathology of cardiovascular disease and influence inflammatory processes as well as function of leukocytes, vascular and cardiac cells, thereby impacting on vessels and heart. Statins form the first-line therapy with the aim to block cholesterol synthesis, but additional lipid-lowering drugs are sometimes needed to achieve low-density lipoprotein (LDL) cholesterol target values. Furthermore, beyond LDL cholesterol, also other lipid mediators contribute to cardiovascular risk. This review comprehensively discusses low- and high-density lipoprotein cholesterol, lipoprotein (a), triglycerides as well as fatty acids and derivatives in the context of cardiovascular disease, providing mechanistic insights into their role in pathological processes impacting on cardiovascular disease. Also, an overview of applied as well as emerging therapeutic strategies to reduce lipid-induced cardiovascular burden is provided.

Effect of acyl and alkyl analogs of platelet-activating factor on inflammatory signaling

Platelet-activating factor (PAF), a bioactive ether phospholipid with significant pro-inflammatory properties, was identified almost half a century ago. Despite extensive study of this autocoid, therapeutic strategies for targeting its signaling components have not been successful, including the recent clinical trials with darapladib, a drug that targets plasma PAF-acetylhydrolase (PAF-AH). We recently provided experimental evidence that the previously unrecognized acyl analog of PAF, which is concomitantly produced along with PAF during biosynthesis, dampens PAF signaling by acting both as a sacrificial substrate for PAF-AH and probably as an endogenous PAF-receptor antagonist/partial agonist. If this is the scenario in vivo, PAF-AH needs to catalyze the selective hydrolysis of alkyl-PAF and not acyl-PAF. Accordingly, different approaches are needed for treating inflammatory diseases in which PAF signaling is implicated. The interplay between acyl-PAF, alkyl-PAF, PAF-AH, and PAF-R is complex, and the outcome of this interplay has not been previously appreciated. In this review, we discuss this interaction based on our recent findings. It is very likely that the relative abundance of acyl and alkyl-PAF and their interactions with PAF-R in the presence of their hydrolyzing enzyme PAF-AH may exert a modulatory effect on PAF signaling during inflammation.

Organophosphate toxicity: updates of malathion potential toxic effects in mammals and potential treatments

Organophosphorus insecticides toxicity is still considered a major global health problem. Malathion is one of the most commonly used organophosphates nowadays, as being considered to possess relatively low toxicity compared with other organophosphates. However, widespread use may lead to excessive exposure from multiple sources. Mechanisms of MAL toxicity include inhibition of acetylcholinesterase enzyme, change of oxidants/antioxidants balance, DNA damage, and facilitation of apoptotic cell damage. Exposure to malathion has been associated with different toxicities that nearly affect every single organ in our bodies, with CNS toxicity being the most well documented. Malathion toxic effects on liver, kidney, testis, ovaries, lung, pancreas, and blood were also reported. Moreover, malathion was considered as a genotoxic and carcinogenic chemical compound. Evidence exists for adverse effects associated with prenatal and postnatal exposure in both animals and humans. This review summarizes the toxic data available about malathion in mammals and discusses new potential therapeutic modalities, with the aim to highlight the importance of increasing awareness about its potential risk and reevaluation of the allowed daily exposure level.

Paraoxonase-1: Characteristics and Role in Atherosclerosis and Carotid Artery Disease

Paraoxonase-1 (PON-1) is a calcium-dependent enzyme that is synthesized in the liver and then secreted in blood where it is bound to high density lipoprotein (HDL). PON-1 is a hydrolase with a wide range of substrates, including lipid peroxides. It is considered responsible for many of the antiatherogenic properties of HDL. PON-1 prevents low density lipoprotein (LDL) oxidation, a process that is considered to contribute to the initiation and development of atherosclerosis. PON-1 activity and levels are influenced by gene polymorphisms; of the 2 common variants, one is in position 192 (Q192R) and one in position 55 (M55L). Also, many drugs affect PON-1 activity. The role of PON-1 in carotid atherosclerosis is inconsistent. Some studies show an association of PON-1 polymorphisms with carotid plaque formation, whereas others do not. The aim of this review is to summarize the characteristics of PON-1, its interactions with drugs and its role in atherosclerosis and especially its relationship with carotid artery disease.

High-density lipoproteins during sepsis: from bench to bedside

High-density lipoproteins (HDLs) represent a family of particle characterized by the presence of apolipoprotein A-I (apoA-I) and by their ability to transport cholesterol from peripheral tissues back to the liver conferring them a cardioprotective function. HDLs also display pleiotropic properties including antioxidant, anti-apoptotic, anti-thrombotic, anti-inflammatory, or anti-infectious functions. Clinical data demonstrate that HDL cholesterol levels decrease rapidly during sepsis and that these low levels are correlated with morbi-mortality. Experimental studies emphasized notable structural and functional modifications of HDL particles in inflammatory states, including sepsis. Finally, HDL infusion in animal models of sepsis improved survival and provided a global endothelial protective effect. These clinical and experimental studies reinforce the potential of HDL therapy in human sepsis. In this review, we will detail the different effects of HDLs that may be relevant under inflammatory conditions and the lipoprotein changes during sepsis and we will discuss the potentiality of HDL therapy in sepsis.

[Serum annexin A2 level is significantly elevated in patients with coronary heart disease]

OBJECTIVE

To analyze the correlation of annexin A2 with coronary atherosclerotic heart disease (CAD) and the severity of CAD.

METHODS

We collected data from a total of 200 inpatients admitted in our department between August, 2017 and August, 2019. According to the.

RESULTS

of coronary angiography, the patients were divided into CAD group (n=150) and non-CAD (n=50), and the CAD patients was further divided, according to their clinical stability, into stable angina (SAP) group and acute coronary syndrome (ACS) group. Serum levels of annexin A2, MPO and PON1 were detected in all these patients, and their correlations with CAD, disease severity, and degree of coronary artery stenosis were analyzed.ResultsThe levels of annexin A2 and MPO were significantly higher in CAD patients than in non-CAD patients (P < 0.05). Among the CAD patients, those with ACS had significantly higher levels of annexin A2 (P < 0.05) and lower levels of PON-1 (P < 0.05) than those with SAP, but annexin A2 level was not significantly correlated with coronary lesion count, Gensini score, or the co-morbidity of diabetes.

CONCLUSIONS

Annexin A2 is significantly elevated in patients with CAD, especially in those with ACS, and can be used as a predictor of clinical instability.

Assessing Plasma Total Homocysteine in Patients with End-Stage Renal Disease

Elevated plasma total homocysteine (tHcy) is a risk factor for cardiovascular disease; however, in light of several recent randomized trials, the issue of causality has been cast into doubt. Patients with end-stage renal disease are particularly interesting as they consistently have elevated tHcy and their leading causes of morbidity and mortality are related to cardiovascular disease. In the present article, we review the early evidence for the homocysteine theory of atherosclerosis, homocysteine metabolism, mechanisms of toxicity, and pertinent available clinical investigations. Where appropriate, the sparse evidence of homocysteine in peritoneal dialysis is reviewed. We conclude by addressing the difficulties associated with lowering plasma tHcy in patients with end-stage renal disease and suggest some novel methods for lowering tHcy in this resistant population. Finally, to address the issue of causality, we recommend that clinicians and scientists await the results of the FAVORIT trial before abandoning homocysteine as a modifiable risk factor for cardiovascular disease, as this study has recruited patients from a population with consistently elevated plasma tHcy who are known to respond to vitamin therapy.

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.

The effects of oxidative stress on the development of atherosclerosis

Atherosclerosis is a cardiovascular disease (CVD) known widely world wide. Several hypothesizes are suggested to be involved in the narrowing of arteries during process of atherogenesis. The oxidative modification hypothesis is related to oxidative and anti-oxidative imbalance and is the most investigated. The aim of this study was to review the role of oxidative stress in atherosclerosis. Furthermore, it describes the roles of oxidative/anti-oxidative enzymes and compounds in the macromolecular and lipoprotein modifications and in triggering inflammatory events. The reactive oxygen (ROS) and reactive nitrogen species (RNS) are the most important endogenous sources produced by non-enzymatic and enzymatic [myeloperoxidase (MPO), nicotinamide adenine dinucleotide phosphate (NADH) oxidase and lipoxygenase (LO)] reactions that may be balanced with anti-oxidative compounds [glutathione (GSH), polyphenols and vitamins] and enzymes [glutathione peroxidase (Gpx), peroxiredoxins (Prdx), superoxide dismutase (SOD) and paraoxonase (PON)]. However, the oxidative and anti-oxidative imbalance causes the involvement of cellular proliferation and migration signaling pathways and macrophage polarization leads to the formation of atherogenic plaques. On the other hand, the immune occurrences and the changes in extra cellular matrix remodeling can develop atherosclerosis process.

Association of PON1-L55M Genetic Variation and Breast Cancer Risk: A Case-Control Trial

Background:

Paraoxonase 1 (PON1), a multifactorial antioxidant enzyme, has a defensive role against oxidative stress, which is believed to contribute to cancer development. This study aimed to investigate the association of PON1-L55M functional polymorphism with breast cancer risk.

Material and methods:

In the experimental study, blood samples were collected from 150 healthy women controls and 150 breast cancer subjects. The L55M genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism.

Results:

Our analysis showed that the genotypes distribution is in Hardy-Weinberg equilibrium for both case and control groups. Our data revealed that there are significant associations between PON1-L55M polymorphism and breast cancer risk in homozygote (OR= 2.13, 95%CI= 1.14-4.00, p= 0.018), dominant (OR= 1.72, 95%CI= 1.07-2.76, p= 0.024), and allelic (OR= 1.55, 95%CI= 1.12-2.15, p= 0.008) models.

Conclusions:

Our results suggest that the PON1-L55M genetic variation could be a genetic risk factor for breast cancer risk and it could be considered as a molecular biomarker for screening of susceptible women.

Pro-Oxidative and Proinflammatory Effects After Traveling From Los Angeles to Beijing

Background:

Exposure to air pollution increases cardiovascular morbidity and mortality. Preventing chronic cardiovascular diseases caused by air pollution relies on detecting the early effects of pollutants on the risk of cardiovascular disease development, which is limited by the lack of sensitive biomarkers. We have previously identified promising biomarkers in experimental animals but comparable evidence in humans is lacking.

Methods:

Air pollution is substantially worse in Beijing than in Los Angeles. We collected urine and blood samples from 26 nonsmoking, healthy adult residents of Los Angeles (mean age, 23.8 years; 14 women) before, during, and after spending 10 weeks in Beijing during the summers of 2014 and 2015. We assessed a panel of circulating biomarkers indicative of lipid peroxidation and inflammation. Personal exposure to polycyclic aromatic hydrocarbons (PAHs), a group of combustion-originated air pollutants, was assessed by urinary PAH metabolite levels.

Results:

Urinary concentrations of 4 PAH metabolites were 176% (95% CI, 103% to 276%) to 800% (95% CI, 509% to 1780%) greater in Beijing than in Los Angeles. Concentrations of 6 lipid peroxidation biomarkers were also increased in Beijing, among which 5-, 12-, and 15-hydroxyeicosatetraenoic acid and 9- and 13-hydroxyoctadecadienoic acid levels reached statistical significance (false discovery rate <5%), but not 8-isoprostane (20.8%; 95% CI, −5.0% to 53.6%). The antioxidative activities of paraoxonase (−9.8%; 95% CI, −14.0% to −5.3%) and arylesterase (−14.5%; 95% CI, −22.3% to −5.8%) were lower and proinflammatory C-reactive protein (101%; 95% CI, 3.3% to 291%) and fibrinogen (48.3%; 95% CI, 4.9% to 110%) concentrations were higher in Beijing. Changes in all these biomarkers were reversed, at least partially, after study participants returned to Los Angeles. Changes in most outcomes were associated with urinary PAH metabolites ( P <0.05).

Conclusions:

Traveling from a less-polluted to a more-polluted city induces systemic pro-oxidative and proinflammatory effects. Changes in the levels of 5-, 12-, and 15-hydroxyeicosatetraenoic acid and 9- and 13-hydroxyoctadecadienoic acid as well as paraoxonase and arylesterase activities in the blood, in association with exposures to PAH metabolites, might have important implications in preventive medicine as indicators of increased cardiovascular risk caused by air pollution exposure.

Paraoxonase 3: Structure and Its Role in Pathophysiology of Coronary Artery Disease

Spanning three decades in research, Paraoxonases (PON1) carried potential of dealing with neurotoxicity of organophosphates entering the circulation and preventing cholinergic crisis. In the past few years, the Paraoxonase multigene family (PON1, PON2, PON3) has been shown to play an important role in pathogenesis of cardiovascular disorders including coronary artery disease (CAD). The PON genes are clustered in tandem on the long arm of human chromosome 7 (q21, 22). All of them have been shown to act as antioxidants. Of them, PON3 is the least studied member as its exact physiological substrate is still not clear. This has further led to limitation in our understanding of its role in pathogenesis of CAD and development of the potential therapeutic agents which might modulate its activity, expression in circulation and tissues. In the present review, we discuss the structure and activity of human PON3 enzyme and its Single nucleotide variants that could potentially lead to new clinical strategies in prevention and treatment of CAD.

PON1 lactonase activity and its association with cardiovascular disease

BACKGROUND

Paraoxonase 1 (PON1) is important in the development of atherosclerosis, and it has become the subject of intensive research. Our aim was to evaluate the association of serum PON1 activity and polymorphisms with cardiovascular disease (CVD) using four different substrates.

MATERIALS AND METHODS

Activity of PON1-related to arylesterase (AREase and 4-CMPAse), paraoxonase (PONase), and lactonase (LACase), and polymorphisms (A-162G, T-108C, L55M, and Q192R) were evaluated in subjects with CVD, cardiovascular risk factor (CFR), and controls. An ordered logistic-regression analysis of PON1 phenotypes was performed in the CVD group with respect to the control group.

RESULTS AND CONCLUSIONS

Logistic-regression analysis showed that CC-108 genotype was associated with CRF and CVD. The CVD group had the lowest activities of PON1. The LACase might be a better biomarker for CVD (OR, 0.52; 95% CI, 0.44-0.61) followed by CMPAse (OR, 0.82; 95% CI, 0.77-0.86), AREase (OR, 0.98; 95% CI, 0.97-0.99) and PONase (OR, 0.99, 95% CI, 0.99-0.99). Logistic regression of PON1 phenotypes by haplotypes showed that LACase activity was not influenced by the polymorphisms and that it could be a new potential biomarker in the development of CVD. Larger scale longitudinal studies are required.

HDL Cholesterol Efflux is Impaired in Older Patients with Early Sepsis: A Subanalysis of a Prospective Pilot Study

BACKGROUND

Proper functioning of high-density lipoprotein (HDL) is necessary for protection against sepsis. However, previous work has demonstrated that HDL becomes oxidized and dysfunctional (Dys-HDL) during sepsis. Older (aged >65 years) patients are at particularly high risk of sepsis and poor outcomes from sepsis.

STUDY OBJECTIVE

The aim of the study was to compare functional properties of HDL (cholesterol efflux capacity and paraoxonase enzyme 1 [PON-1] activity) and Dys-HDL between older (aged >65 years) sepsis patients and older healthy volunteers.

METHODS

This was a subanalysis of a prospective study in which patients with sepsis were prospectively enrolled from the emergency department within the first 24 h. Serum and plasma samples were drawn from septic patients and age- and sex-matched control subjects. Percent cholesterol efflux, HDL inflammatory index, and PON1 activity were measured. Data were analyzed using Student t test or Wilcoxon rank-sum test.

RESULTS

Ten sepsis and 10 healthy controls were analyzed. Mean age of sepsis patients (80 ± 2 years [SD]) and control subjects (77 ± 2 years) was similar (P = 0.31). Mean systolic blood pressures were significantly different in sepsis patients (113 ± 8 mmHg) compared with controls (133 ± 6 mmHg) (P = 0.049). Median SOFA scores for sepsis patients were 5.5 (interquartile range [IQR] 4-9). Mean percent cholesterol efflux was significantly reduced in sepsis (24.1 ± 1.2%) compared with controls (31.5 ± 1.0%) (P < 0.001). HDL inflammatory index was also significantly elevated in septic patients (1.63, IQR 1.3-2.34) compared with controls (0.62, IQR 0.56-0.67) (P < 0.001). However, PON1 activity was not significantly different between septic patients (70.3 ± 16.3 nmol/min/mL) and control subjects (88.8 ± 18.3 nmol/min/mL).

CONCLUSIONS

Cholesterol efflux capacity seems to be significantly impaired in sepsis patients who also exhibited a higher index of Dys-HDL. The findings suggest that HDL function may be impaired in older individuals with sepsis.

Effects of nanoparticles exposure and PON1 genotype on heart rate variability

OBJECTIVES

This study was to assess the association between different NPs exposure and PON1 genotype on Heart Rate Variability (HRV) parameters among workers.

METHODS

This study included 235 non-CVD subjects handled to nanomaterials (NM) and 185 non-exposed controls without CVD from 14 NM plants. All participants completed short-term HRV measurements, and were collected blood specimens to measure PON1 activities and the genotype of the PON1 Q192R polymorphism.

RESULTS

In a multivariate regression model, this study observed a positive relationship between nano-Ag exposure and HRV time-domain (RMSSD) and frequency-domain (HF). After adjusting for confounders, the results showed positive associations between RR homozygosity, PON1 paraoxonase/arylesterase activities with HRV, and was particularly noteworthy in RMSSD and HF.

CONCLUSIONS

This study shows a significant increment of RMSSD and HF among workers who handled Nano-Ag materials. These results imply that Nano-Ag and PON1 Q192R genotype can trigger ANS reflexes and alter cardiac frequency and function.

Expression levels of paraoxonase-1 in aortic valve tissue are associated with the progression of calcific aortic valve stenosis

Background

Paraoxonase-1 (PON1) participates in several vital steps of lipid metabolism, which is associated with calcific aortic valve stenosis (CAVS). Although a few studies have suggested that PON1 in blood could inhibit aortic valve calcification, they did not provide detailed descriptions. In this study, we hypothesized that PON1 is expressed in the aortic valve and that the PON1 level is related to the severity of CAVS.

Methods

A total of 118 consecutive patients with CAVS were enrolled in the study; 35 individuals without aortic valve calcification were included in the control group. Aortic valve tissue was obtained from postoperative pathologic specimens. PON1 was detected qualitatively using immunohistochemistry and quantitatively using an enzyme-linked immunosorbent assay. The severity of aortic stenosis was evaluated using echocardiography.

Results

We detected PON1 in the aortic valve and noticed that the PON1 level was significantly lower in the case group than in the control group (P<0.001). Furthermore, we found no significant difference between the mild and moderate stenosis groups (P=0.395). However, the PON1 levels were obviously higher in both the mild and moderate stenosis groups than in the severe stenosis group (both P<0.001). We also detected a significant negative correlation between PON1 level and the maximum aortic valve gradient in the case group.

Conclusions

We detected PON1 in the aortic valve for the first time, and our results suggest that the PON1 level in aortic valve tissue decreases with increasing severity of aortic valve stenosis.

Ticagrelor induces paraoxonase-1 (PON1) and better protects hypercholesterolemic mice against atherosclerosis compared to clopidogrel

Ticagrelor (TIC), a P2Y purinoceptor 12 (P2Y₁₂)-receptor antagonist, has been widely used to treat patients with acute coronary syndrome. Although animal studies suggest that TIC protects against atherosclerosis, it remains unknown whether it does so through its potent platelet inhibition or through other pathways. Here, we placed hypercholesterolemic Ldlr^-/-Apobec1^-/- mice on a high-fat diet and treated them with either 25 mg/kg/day of clopidogrel (CLO) or 180 mg/kg/day of TIC for 16 weeks and evaluated the extent of atherosclerosis. Both treatments equally inhibited platelets as determined by ex vivo platelet aggregation assays. The extent of atherosclerosis, however, was significantly less in the TIC group than in the CLO group. Immunohistochemical staining and ELISA showed that TIC treatment was associated with less macrophage infiltration to the atherosclerotic intima and lower serum levels of CCL4, CXCL10, and TNFα, respectively, than CLO treatment. Treatment with TIC, but not CLO, was associated with higher serum activity and tissue level of paraoxonase-1 (PON1), an anti-atherosclerotic molecule, suggesting that TIC might exert greater anti-atherosclerotic activity, compared with CLO, through its unique ability to induce PON1. Although further studies are needed, TIC may prove to be a viable strategy in the prevention and treatment of chronic stable human atherosclerosis.

PON1 increases cellular DNA damage by lactone substrates

Paraoxonase 1 (PON1) is a high-density lipoprotein (HDL)-associated enzyme that by hydrolysing exogenous and endogenous substrates can provide protection against substrate induced toxicity. To investigate the extent to which PON1 provides protection against lactone induced DNA damage, DNA damage was measured in HepG2 cells using the neutral Comet assay following lactone treatment in the presence and absence of exogenous recombinant PON1 (rPON1). Low dose lactones (10 mM) caused little or no damage while high doses (100 mM) induced DNA damage in the following order of potency: α-angelica lactone > γ-butyrolactone ~ γ-hexalactone > γ-heptalactone ~ γ-octaclactone ~ γ-furanone ~ γ-valerolactone > γ-decalactone. Co-incubation of 100 mM lactone with rPON1, resulted in almost all cells showing extensive DNA damage, particularly with those lactones that decreased rPON1 activity by > 25%. In contrast, with the lactones that are poor rPON1 subtrates (γ-decalactone and γ-furanone), rPON1 did not increase DNA damage. DNA damage induced by a 1 h co-treatment with 10 mM α-angelica lactone and rPON1 was reduced when cells when incubated for a further 4 h in fresh medium suggesting break formation was due to induced DNA damage rather than apoptosis. Preincubation (1-6 h) of α-angelica lactone with rPON1 in the absence of cells, decreased cellular DNA damage by around 40%  in comparison to cells treated without preincubation. These results suggest that in addition to its well-recognised detoxification effects, PON1 can increase genotoxicity potentially by hydrolysing certain lactones to reactive intermediates that increase DNA damage via the formation of DNA adducts.

Albuminuria, the High-Density Lipoprotein Proteome, and Coronary Artery Calcification in Type 1 Diabetes Mellitus

Objective- Albuminuria is an important risk factor for cardiovascular disease in diabetes mellitus. We determined whether albuminuria associates with alterations in the proteome of HDL (high-density lipoprotein) of subjects with type 1 diabetes mellitus and whether those alterations associated with coronary artery calcification. Approach and Results- In a cross-sectional study of 191 subjects enrolled in the DCCT (Diabetes Control and Complications Trial)/EDIC study (Epidemiology of Diabetes Interventions and Complications), we used isotope dilution tandem mass spectrometry to quantify 46 proteins in HDL. Stringent statistical analysis demonstrated that 8 proteins associated with albuminuria. Two of those proteins, AMBP (α1-microglobulin/bikunin precursor) and PTGDS (prostaglandin-H2 D-isomerase), strongly and positively associated with the albumin excretion rate ( P<10^-6). Furthermore, PON (paraoxonase) 1 and PON3 levels in HDL strongly and negatively associated with the presence of coronary artery calcium, with odds ratios per 1-SD difference of 0.63 (95% CI, 0.43-0.92; P=0.018) for PON1 and 0.59 (95% CI, 0.40-0.87; P=0.0079) for PON3. Only 1 protein, PON1, associated with both albumin excretion rate and coronary artery calcification. Conclusions- Our observations indicate that the HDL proteome is remodeled in type 1 diabetes mellitus subjects with albuminuria. Moreover, low concentrations of the antiatherosclerotic protein PON1 in HDL associated with both albuminuria and coronary artery calcification, raising the possibility that alterations in HDL protein cargo mediate, in part, the known association of albuminuria with cardiovascular risk in type 1 diabetes mellitus. Visual Overview- An online visual overview is available for this article.

Betaine modulates oxidative stress, inflammation, apoptosis, autophagy, and Akt/mTOR signaling in methionine-choline deficiency-induced fatty liver disease

We examined the effects of betaine, an endogenous and dietary methyl donor essential for the methionine-homocysteine cycle, on oxidative stress, inflammation, apoptosis, and autophagy in methionine-choline deficient diet (MCD)-induced non-alcoholic fatty liver disease (NAFLD). Male C57BL/6 mice received standard chow (control), standard chow and betaine (1.5% w/v in drinking water), MCD, or MCD and betaine. After six weeks, serum and liver samples were collected for analysis. Betaine reduced MCD-induced increase in liver transaminases and inflammatory infiltration, as well as hepatosteatosis and serum levels of low-density lipoprotein, while it increased that of high-density lipoprotein. MCD-induced hepatic production of reactive oxygen and nitrogen species was significantly reduced by betaine, which also improved liver antioxidative defense by increasing glutathione content and superoxide-dismutase, catalase, glutathione peroxidase, and paraoxonase activity. Betaine reduced the liver expression of proinflammatory cytokines tumor necrosis factor and interleukin-6, as well as that of proapoptotic mediator Bax, while increasing the levels of anti-inflammatory cytokine interleukin-10 and antiapoptotic Bcl-2 in MCD-fed mice. In addition, betaine increased the expression of autophagy activators beclin 1, autophagy-related (Atg)4 and Atg5, as well as the presence of autophagic vesicles and degradation of autophagic target sequestosome 1/p62 in the liver of NAFLD mice. The observed effects of betaine coincided with the increase in the hepatic phosphorylation of mammalian target of rapamycin (mTOR) and its activator Akt. In conclusion, the beneficial effect of betaine in MCD-induced NAFLD is associated with the reduction of liver oxidative stress, inflammation, and apoptosis, and the increase in cytoprotective Akt/mTOR signaling and autophagy.

High-Density Lipoprotein Function and Dysfunction in Health and Disease

High-density lipoprotein cholesterol (HDL-c) has long been referred to as 'good cholesterol' due to its apparent inverse relationship with future CVD risk. More recent research has questioned a causal role for HDL-c in this relationship, however, as both genetic studies and numerous large-scale randomised controlled trials have found no evidence of a cardiovascular protective effect when HDL-c levels are raised. Instead, focus has switched to the functional properties of the HDL particle. Evidence suggests that both the composition and function of HDL may be significantly altered in the context of an inflammatory milieu, transforming the particle from a vasoprotective anti-atherogenic particle to a noxious pro-atherogenic equivalent. This review will summarise evidence relating HDL to CVD risk, explore recent evidence characterising changes in the composition and function of HDL that may occur in chronic inflammatory diseases, and discuss the potential for future HDL-modifying therapeutic interventions.

Association between paraoxonase-1 gene Q192R and L55M polymorphisms and risk of gastric cancer: A case-control study from Iran

The aim of the present study was to examine the relation between two paraoxonase1 (PON1) polymorphisms, Q192R and L55M and susceptibility to gastric cancer in an Iranian population. In this case-control study the PON1 polymorphisms were assessed in 90 gastric cancer patients and 90 healthy controls by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Regarding PON1 Q192R polymorphism, a significant increase in the R allele in the patient group compared with the controls (p value = 0.0006) While the Q allele was more frequent in the control group. No significant difference was found in the genotype or allele frequency of the L55M polymorphism between healthy individuals and patients with gastric cancer. Our results demonstrated the protective effect of Q allele against gastric cancer.

Tampon use, environmental chemicals and oxidative stress in the BioCycle study

BACKGROUND

Tampons are used by up to 86% of US women and are a rarely considered potential source of pesticide and metal exposure. Tampons may be of particular concern given the likely higher absorption that occurs in the vagina. Our objective was to examine the potential associations between tampon use and metal concentrations, and biomarkers of inflammation and oxidative stress among healthy women.

METHODS

We used information from a prospective cohort of 259 regularly menstruating women, aged 18-44, followed for two menstrual cycles. Tampon use was assessed using information provided in participant study diaries. Metal concentrations were measured from a blood sample collected at enrollment. Oxidative stress and inflammation biomarker concentrations were determined from blood samples collected at up to 8 clinic visits for each cycle. Linear regression models were used to estimate associations of tampon use with metal exposure, and linear mixed models to estimate associations of tampon use with inflammation and oxidative stress biomarkers at different times during the menstrual cycle.

RESULTS

We observed non-significantly higher mean levels of mercury for tampon users compared to non-tampon users (exp(β) = 1.25, 95% CI = 0.93, 1.68). We found no evidence of an association between tampon use and inflammation biomarkers. We observed consistently higher isoprostane levels, an oxidative stress biomarker, among tampon users compared to non-tampon users (e.g. exp.(β) = 1.05, 95%CI = 0.96, 1.16, for the average isoprostane during the menstruating week); however, these results were not statistically significant.

CONCLUSIONS

While our results are not statistically significant, we observed suggestive associations between tampon use and elevated levels of mercury and oxidative stress biomarkers. Although our finding should be interpreted in light of our limitations, they indicate that tampons may be a source of exposure to metals and chemicals that have been largely ignored, and any related health effects are an important public health concern.

Can Carob-Fruit-Extract-Enriched Meat Improve the Lipoprotein Profile, VLDL-Oxidation, and LDL Receptor Levels Induced by an Atherogenic Diet in STZ-NAD-Diabetic Rats?

Carob fruit extract (CFE) has shown remarkable in vitro antioxidant properties and reduces postprandial hyperglycemia and hyperlipidemia in healthy animals. Development of functional meat products that contain bioactive components are presented as a great nutritional strategy. Until now, the effect of the consumption of restructured meat enriched with CFE in a murine model of diabetes has not been investigated. The objective of this study was to evaluate the effect on glycemia, lipemia, lipoprotein profile, Ldlr, arylesterase (AE), and very low-density lipoproteins (VLDL) and liver oxidation in streptozotocin-nicotinamide (STZ-NAD) growing Wistar diabetic rats fed restructured meat in the frame of a high cholesterol/high saturated-fat diet. In the present study, three groups (D, ED and DE) were fed cholesterol-enriched (1.4% cholesterol and 0.2% cholic acid) and high saturated-fat diets (50% of total energy from fats and 20.4% from saturated fatty acids). Rats were subjected to a STZ-NAD administration at the 3rd week. Group D did not receive CFE, while ED and DE rat groups received CFE before and after the diabetic induction, respectively. After eight weeks, D rats showed hyperglycemia and hypercholesterolemia, an increased amount cholesterol-enriched VLDL (β-VLDL), IDL and LDL particles and triglyceride-enriched HDL. ED and DE partially blocked the hypercholesterolemic induction with respect to D group (p < 0.001) and improved glycemia, cholesterol levels, lipoprotein profile, Ldlr, plasma AE activity and liver oxidation (p < 0.001). Fecal fat, moisture and excretion were higher while dietary digestibility was lower in ED and DE vs. D counterparts (p < 0.0014). In conclusion, CFE-enriched meat shows, for the first time, hypoglycemic and hypolipidemic effects in STZ-NAD animals fed high cholesterol/high saturated-fat diets. Likewise, it manages to reverse possible diabetes lipoprotein alterations if CFE-enriched meat is consumed before pathology development or improves said modifications if Type 2 Diabetes Mellitus is already established.

Exogenous (Pomegranate Juice) or Endogenous (Paraoxonase1) Antioxidants Decrease Triacylglycerol Accumulation in Mouse Cardiovascular Disease-Related Tissues

The polyphenol-rich pomegranate juice (PJ) and the high-density lipoprotein (HDL)-associated paraoxonase1 (PON1) are known as potent atheroprotective antioxidants, but their effects on other tissues related to cardiovascular disease (CVD) remain unknown. The current study aimed to investigate the effects of treating mice with PJ or recombinant PON1 (rePON1) on the oxidation and lipid status of CVD-related tissues: serum, aorta, heart, liver, kidney, visceral, and subcutaneous adipose tissues (VAT and SAT). Both PJ consumption and rePON1 injection decreased the serum levels of thiobarbituric acid-reactive substances (16% and 19%) and triacylglycerols (TAG, 24% and 27%), while only rePON1 increased the levels of thiol groups (35%) and decreased serum cholesterol (15%). Both PJ and rePON1 significantly decreased aortic cholesterol (38% and 32%) and TAG (62% and 58%) contents in association with downregulation of the key TAG biosynthetic enzyme diacylglycerol O-acyltransferase 1 (DGAT1, 71% and 65%), while only PJ decreased aortic lipid peroxides (47%). Substantial TAG-lowering effects of both PJ and rePON1 were observed also in the heart (31% and 42%), liver (34% and 42%), and kidney (42% and 57%). In both VAT and SAT, rePON1 decreased the levels of lipid peroxides (28% and 25%), while PJ decreased the TAG content (22% and 18%). Ex vivo incubation of SAT with serum derived from mice that consumed PJ or injected with rePON1 decreased SAT lipid peroxides (35% or 28%) and TAG mass (12% or 10%). These novel findings highlight potent TAG-lowering properties of exogenous (PJ) and endogenous (PON1) antioxidants in tissues associated with CVD.

Effect of high-density lipoprotein on oocyte maturation and bovine embryo development in vitro

High-density lipoprotein (HDL) is the main lipoprotein in the follicular fluid, and it has anti-inflammatory, antioxidant and cryoprotectant properties. The anti-inflammatory potential and antioxidant potential are derived from its lipid composition, especially the apolipoprotein AI (ApoAI) and paraoxonase 1 (PON1). The aim of this study was to evaluate the effect of HDL during in vitro maturation (IVM) on oocyte maturation and early bovine embryo development. For this, cumulus-oocyte complexes (COCs) were obtained from bovine ovaries collected at a local slaughterhouse. COCs (n = 2,250) were allocated into three groups (n = 50 COCs/group) according to the addition of HDL protein (HDL-P) during IVM for 22 hr: 0 (control), 50 and 150 mg/dl. After IVM, COCs were inseminated (in vitro fertilization) and cultivated for 7 days. Total cholesterol concentration, total protein, triglycerides and ApoAI concentrations on IVM medium increased proportionally to HDL-P addition. However, PON1 activity was not detected in any treatment. The addition of HDL-P did not affect nuclear maturation rate, endogenous reactive oxygen species and glutathione levels in COCs (p > 0.05). The highest HDL-P concentration (150 mg/dl) decreased cleavage and blastocyst rate (p < 0.05). Moreover, the HDL-P 150 mg/dl group had lower cellular count/blastocyst than the 50 mg/dl group (p < 0.05). However, the addition of HDL-P did not affect relative gene expression of evaluated genes. In conclusion, the complex HDL/ApoAI obtained from human plasma, in the absence of PON1 activity during in vitro oocyte maturation, decreased initial embryo development.

Associations of the PON1 rs662 polymorphism with circulating oxidized low-density lipoprotein and lipid levels: a systematic review and meta-analysis

BACKGROUND

Several meta-analyses have demonstrated that the rs662 polymorphism in Paraoxonase 1 gene (PON1) gene is associated with coronary heart disease (CHD). However, it is still uncertain whether this polymorphism is associated with the plasma levels of oxidized low-density lipoprotein (Ox-LDL) and lipids. This meta-analysis is aimed to clarify the relationships between the rs662 polymorphism and plasma levels of Ox-LDL and lipids.

METHODS

By searching in PubMed, Google Scholar, Web of Science, Cochrane Library, Wanfang, VIP and CNKI databases, 5 studies (1369 subjects) and 85 studies (46,740 subjects) were respectively identified for Ox-LDL association analysis and lipid association analysis. Standardized mean difference (SMD) was used to estimate the effects of the rs662 polymorphism on plasma Ox-LDL and lipid levels.

RESULTS

The carriers of the variant R allele had higher levels of Ox-LDL (SMD = 0.23, 95% CI = 0.10-0.36, P <  0.01), triglyceride (TG) (SMD = 0.06, 95% CI = 0.01-0.11, P = 0.02), total cholesterol (TC) (SMD = 0.04, 95% CI = 0.00-0.07, P = 0.05) and low-density lipoprotein cholesterol (LDL-C) (SMD = 0.04, 95% CI = 0.00-0.08, P = 0.04) than the non-carriers.

CONCLUSIONS

This meta-analysis suggests that the association between the PON1 rs662 polymorphism and CHD may partly be mediated by abnormal Ox-LDL and lipid levels caused by the R allele.

Evaluation of the prognostic value of paraoxonase 1 in the recurrence and metastasis of hepatocellular carcinoma and establishment of a liver-specific predictive model of survival

Background

Hepatocellular carcinoma is a malignant tumor with a highly invasive and metastatic phenotype, and the detection of potential indicators associated with its recurrence and metastasis after surgical resection is critical for patient survival.

Methods

Transcriptome data for large cohorts (n = 1432) from multicenter sources were comprehensively analyzed to explore such potential signatures. The prognostic value of the selected indicators was investigated and discussed, and a comparison with conventional clinicopathological features was performed. A survival predictive nomogram for 5-year survival was established with the selected indicator using the Cox proportional hazards regression. To validate the indicator at the protein level, we performed immunohistochemical staining with paraffin-embedded slides of hepatocellular carcinoma samples (n = 67 patients) from our hospital. Finally, a gene set enrichment analysis (GSEA) was performed to detect the underlying biological processes and internal mechanisms.

Results

The liver-specific protein paraoxonase 1 (PON1) was found to be the most relevant indicator of tumor recurrence, invasiveness, and metastasis in the present study, and the downregulation of PON1 might reveal poor survival for patients with hepatocellular carcinoma. The C-index of the PON1-related nomogram was 0.714, thus indicating a more effective predictive performance than the 7th American Joint Committee on Cancer (AJCC) tumor stage (0.534), AJCC T stage (0.565), or alpha-fetoprotein (0.488). The GSEA revealed that PON1 was associated with several hepatocellular carcinoma-related pathways, including the cell cycle, DNA replication, gap junction and p53 downstream pathways.

Conclusions

The downregulation of paraoxonase 1 may suggest worse outcomes and a higher recurrence rate. Thus, paraoxonase 1 might represent an indicator for predicting the survival of patients with hepatocellular carcinoma.

Electronic supplementary material

The online version of this article (10.1186/s12967-018-1707-0) contains supplementary material, which is available to authorized users.

Evaluating the link between Paraoxonase-1 levels and Alzheimer's disease development

At present, the etiopathogenesis of Alzheimer's disease (AD), the most common form of dementia, remains far to be fully deciphered. In the recent years, also the centrality of amyloid-β peptide in the pathogenesis of the neurodegenerative disease has been questioned and other hypotheses have been advanced. Notably, a common denominator of many of these theoretical models is represented by oxidative stress, which is widely proposed to play a role in the disease initiation and/or progression. Paraoxonase 1 (PON1) is a high-density lipoprotein (HDL)-associated enzyme that endows its carrier with multiple biological functions, including the ability to contrast oxidative damage to lipid components of lipoproteins and cells and protect from toxicity of specific organophosphorus pesticides. The peculiar multi-functionality nature of PON1 might be the key for explaining the vast epidemiological data showing a close association between low serum PON1 activity and risk of several diseases, including cardiovascular and neurodegenerative diseases, in particular AD. In this review, we discuss the possible link between PON1 with AD pathogenesis and we hypothesize eventual mechanistic pathways that could account from epidemiological observations. We also highlight the methodological issue limitation in PON1 studies that still impede to give a definitive and certain picture of its effective biological impact on human health including AD.

Acute coumaphos organophosphate exposure in the domestic dogs: Its implication on haematology and liver functions

Indiscriminate use of organophosphate acaricides especially among livestock and dog owners in the control of ticks and other ectoparasites has taken a worrisome dimension. In the present study, we investigated, the effects of acute dermal exposure in the form of acaricides baths of coumaphos at different concentrations on the haematology, blood pressure and liver functions in local mongrel dogs.

Twenty-four, male mongrel dogs of about 8 months of age with an average weight of 9.88 ± 0.4 kg were used for the study. The dogs were divided into four groups consisting of six dogs per group. Group A (control) was bathed with ordinary water, while group B was bathed with the recommended concentration of 0.016% (160 ppm) Coumaphos in water. Groups C and D were bathed with 10 and 20 times the recommended dose (1600 ppm and 3200 ppm), respectively.

Significant leucopenia, increased plasma urea and decreased low density lipoprotein (LDL) values were observed at 8 h post exposure, which worsened with time. At 24 and 36 hrs post exposure, normochromic normocytic anaemia, pan leucopenia, bloody diarrhoea, retching, vomiting and paddling were observed in affected animals. Post mortem examination revealed severe lungs, liver and stomach congestion. Multifocal areas of necrosis in the liver and kidney, serosal and mucosal haemorrhages and haemorrhagic meningitis were also observed.

The use of excessively high concentration of organophosphate as acaricides bath is associated with severe anticholinesterase poisoning, which may result in death of affected animals.

High-Density Lipoproteins: Effects on Vascular Function and Role in the Immune Response

The focus in studies of high-density lipoproteins was on their capacity to remove excess cholesterol and deliver it to the liver. Other functions and vascular effects have been described. Clinical trials and translational/genetic studies have led to a refined understanding of the role of high-density lipoprotein; it is likely not a causal cardiovascular risk factor. In healthy subjects, it limits lipid oxidation, protects endothelial cell functions/integrity, and exerts antiinflammatory/antiapoptotic effects. In patients with coronary disease or diabetes, it undergoes modifications/remodeling, resulting in dysfunctional high-density lipoprotein. We summarize recent findings about the regulation of its function and discuss the clinical implications.

Ancient convergent losses of Paraoxonase 1 yield potential risks for modern marine mammals

Mammals diversified by colonizing drastically different environments, with each transition yielding numerous molecular changes, including losses of protein function. Though not initially deleterious, these losses could subsequently carry deleterious pleiotropic consequences. We have used phylogenetic methods to identify convergent functional losses across independent marine mammal lineages. In one extreme case, Paraoxonase 1 (PON1) accrued lesions in all marine lineages, while remaining intact in all terrestrial mammals. These lesions coincide with PON1 enzymatic activity loss in marine species' blood plasma. This convergent loss is likely explained by parallel shifts in marine ancestors' lipid metabolism and/or bloodstream oxidative environment affecting PON1's role in fatty acid oxidation. PON1 loss also eliminates marine mammals' main defense against neurotoxicity from specific man-made organophosphorus compounds, implying potential risks in modern environments.