Can HDL cholesterol be replaced by paraoxonase 1 activity in the prediction of severe coronary artery disease in patients with type 2 diabetes?

Background And Aims: Novel biomarkers are required to improve cardiovascular disease prediction in patients with type 2 diabetes (T2D) as a high-risk population. This study was conducted to examine whether coronary artery disease (CAD) risk assessment can be improved by substituting high-density lipoprotein (HDL)-bound paraoxonase 1 (PON1) activity for HDL cholesterol (HDL-C) concentration in patients with T2D.

Methods And Results: In this study, we studied 139 patients with T2D (mean age 64.

Paraoxonase-1 (PON-1) Arylesterase Activity Levels in Patients with Coronary Artery Disease: A Meta-Analysis.

Aim: To review and compare the PON-1 arylesterase activity between coronary artery disease (CAD) and non-CAD patients.

Methods: Data were obtained by searching MEDLINE and Scopus for all investigations published between January 1, 2000 and March 1, 2021 comparing PON-1 arylesterase activity between CAD and controls.

Results: Twenty studies, based on 5417 patients, met the inclusion criteria and were included in the analysis.

Epigenetics of paraoxonases.

Purpose Of Review: Studies have shown the three-member paraoxonase (PON) multigene family to be involved in the development of a large variety of diseases with an inflammatory component. Environmental factors such as lifestyle-related factors differ widely between populations and it is important to consider that their impacts may be exerted through the epigenetic mechanisms, which connect genes, the environment and disease development and are a potential therapeutic avenue.

Recent Findings: In the review period, very little was published on epigenetics of PON2 or PON3, mostly on their diagnostic value in cancer by measuring methylation levels of these genes.

Phenotypes and concentration of PON1 in cardiovascular disease: The role of nutrient intake.

Background And Aims: Paraoxonase 1 (PON1) is considered to play a crucial role as an anti-atherosclerotic factor. The PON1 activity is affected by genetic polymorphisms, environmental factors, age, sex, lifestyle, pharmaceutical drugs, and dietary factors. The aim of this study was to evaluate the association between macro- and micronutrients as well as PON1 concentration and activities in patients with cardiovascular diseases (CVD), cardiovascular risk factors but no CVD (CRF), and in healthy controls (control group).

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.

The epigenetic regulation of paraoxonase 1 (PON1) as an important enzyme in HDL function: The missing link between environmental and genetic regulation.

Background: Paraoxonase 1 (PON1) is an important antiatherogenic and antioxidant enzyme in the circulation that has been associated with adverse health outcomes particularly cardiovascular disease (CVD) and other metabolic disorders. PON1 is a highly promiscuous enzyme and can hydrolyse a large variety of substrates, however, detailed structure/function studies have concluded that the natural substrates for PON1 are lipophilic lactones. The interindividual variability in PON1 activity has been mainly attributed to genetic determinants; however, it appears that the contribution of epigenetics has been ignored as a result of the lack of adequate research.

PON1 concentration and high-density lipoprotein characteristics as cardiovascular biomarkers.

Introduction: Serum paraoxonase 1 (PON1) is now known to be related to cardiovascular diseases (CVD). The aim of this study was to determine the relationship between PON1 concentration and high-density lipoprotein (HDL) subclasses in patients with proven CVD, cardiovascular risk factors but no CVD (CRF), and in healthy controls (control group).

Material And Methods: A case-control study was carried out with 69 volunteers from the Mexican Institute of Social Security, Mexico.

Unexpectedly higher diazoxon hydrolysis by serum paraoxonase-1 in coronary heart disease.

Objectives: Low serum PON1 activities (paraoxon, phenyl-acetate or lactone substrates) are associated with coronary heart disease (CHD). We investigated the rate of diazoxon hydrolysis by PON1 in a population with CHD.

Design & Methods: Case- control study of 410 subjects with CHD and 274 controls.

Transcriptional regulation of human Paraoxonase 1 by nuclear receptors.

Paraoxonase 1 (PON1) is a calcium-dependent lactonase synthesized primarily in the liver and secreted into the plasma, where it is associates with high density lipoproteins (HDL). PON1 acts as antioxidant preventing low-density lipoprotein (LDL) oxidation, a process considered critical in the initiation and progression of atherosclerosis. Additionally, PON1 hydrolyzes and detoxifies some toxic metabolites of organophosphorus compounds (OPs).

Human paraoxonase-1 (PON1): Gene structure and expression, promiscuous activities and multiple physiological roles.

Human PON1 is a HDL-associated lipolactonase capable of preventing LDL and cell membrane oxidation and is therefore considered to be atheroprotective. PON1 contributes to the antioxidative function of HDL and reductions in HDL-PON1 activity, prevalent in a wide variety of diseases with an inflammatory component, are believed to lead to dysfunctional HDL which can promote inflammation and atherosclerosis. However, PON1 is multifunctional and may contribute to other HDL functions such as in innate immunity, preventing infection by quorum sensing gram negative bacteria by destroying acyl lactone mediators of quorum sensing, and putative new roles in cancer development and the promotion of healthy ageing.

Targeting paraoxonase-1 in atherosclerosis.

Introduction: Paraoxonase-1 (PON1) is a Ca(2+) dependent, high-density lipoprotein-associated lactonase which is capable of retarding/inhibiting low-density lipoprotein (LDL) oxidation. LDL oxidation is believed to be central to the initiation and progression of atherosclerosis, therefore, PON1 is considered to be atheroprotective.

Areas Covered: Relevant literature on PON1 was identified in PubMed.

Paraoxonase-1 (PON1) promoter region polymorphisms, serum PON1 status and coronary heart disease.

Introduction: Serum paraoxonase-1 (PON1) retards the oxidation of low-density lipoprotein and cell membranes and is atheroprotective. Polymorphisms in the promoter region of the PON1 gene have been shown to affect serum PON1 levels and have been related to the presence of coronary heart disease (CHD) in some studies. However, contradictory results have been reported with regard to promoter region polymorphisms and CHD presence; therefore we have re-examined the effects of the C-108T and G-909C promoter polymorphisms on PON1 levels and the presence of CHD in a large case-control study.

Paraoxonase-1 is not associated with coronary artery calcification in type 2 diabetes: results from the PREDICT study.

Objectives: To determine any association between serum paraoxonase-1 (PON1) activity, protein and coding region genetic polymorphisms and coronary artery calcification (CACS) and to determine factors which modulate serum PON1 in type 2 diabetes (T2DM).

Methods And Results: 589 patients (419 Caucasian, 120 South Asian, 50 other) from the PREDICT Study were investigated. All patients were asymptomatic for coronary disease and had established T2DM.

Coincubation of PON1, APO A1, and LCAT increases the time HDL is able to prevent LDL oxidation.

The inhibition of low-density lipoprotein (LDL) oxidation by high-density lipoprotein (HDL) is a major antiatherogenic property of this lipoprotein. This activity is due, in part, to HDL associated proteins. However, whether these proteins interact in the antioxidant activity of HDL is unknown.

Effect of dilution on high-density lipoprotein associated paraoxonase-1 activity.

Objectives: To investigate the effects of dilution on high-density lipoprotein (HDL) associated paraoxonase-1 (PON1) activity.

Design And Methods: HDL was prepared by ultracentrifugation, diluted with TRIS buffer pH 8.2 (0-128 fold) and assayed spectrophotometrically for PON1 activity using paraoxon and phenyl acetate.

Cholesteryl-ester transfer protein enhances the ability of high-density lipoprotein to inhibit low-density lipoprotein oxidation.

Therapeutic strategies to increase high-density lipoprotein (HDL) to treat or prevent vascular disease include the use of cholesteryl-ester transfer protein (CETP) inhibitors. Here, we show, to the best of our knowledge for the first time, that addition of CETP to HDL enhances the ability of HDL to inhibit low-density lipoprotein oxidation by ∼ 30% for total HDL and HDL(2) (both P < 0.05) and 75% for HDL(3) (P < 0.

Immunohistochemical analysis of paraoxonases-1 and 3 in human atheromatous plaques.

Background: The paraoxonase (PON) enzyme family comprising PON1, PON2 and PON3 are antioxidant enzymes that degrade bioactive oxidised lipids and are thus antiatherogenic.

Materials And Methods: We investigated the localisation of the PON proteins during the development of atherosclerosis by immunohistochemical analysis.

Results: In normal aortas, PON1 and PON3 were localised to smooth muscle cells (SMC) and endothelial cells.

Human tissue distribution of paraoxonases 1 and 2 mRNA.

We have studied the distribution of mRNA for paraoxonases (PON) 1 and 2 in 24 human tissues using Gene Expression Panels. PON1 mRNA was restricted to adult kidney, liver, and colon as well as fetal liver, whereas PON2 mRNA was more widely distributed in adult human brain, heart, kidney, spleen, liver, colon, lung, small intestine, muscle, stomach, testis, placenta, salivary, thyroid and adrenal glands, pancreas, skin, and bone marrow, as well as fetal brain and liver. PON2 mRNA was not found in ovary, uterus, or plasma leukocytes using the panels.

Anti-inflammatory properties of paraoxonase-1 in atherosclerosis.

Atherosclerosis is increasingly recognised as an inflammatory disease. The inflammatory process begins with the oxidation of low-density lipoprotein (LDL) in the artery wall. The ability of high-density lipoprotein (HDL) to inhibit the oxidation of LDL (and cell membranes) and promote macrophage cholesterol efflux through the action of several of its associated proteins, particularly paraoxonase-1 (PON1), reduces the inflammation associated with atherosclerosis.

Variability in the measurement of lipoprotein(a) in the British Isles.

Background: Elevated Lipoprotein(a) concentrations are a risk factor for coronary heart disease; however, methodological problems have prevented its introduction to routine clinical practice.

Methods: Thirty-six laboratories each assayed 20 samples (the same 20 in each laboratory) using two different Lp(a) kits per laboratory, randomly assigned from the total of 12 used in the study.

Results: The duplicate error, i.

High-density lipoprotein: why all the fuss?

The current search for new treatments to combat coronary heart disease (CHD) is centred on increasing HDL-cholesterol. The failure of the CETP inhibitor torcetrapib may force a rethink. This perspective briefly reviews the antiatherosclerotic properties of HDL and ways HDL-cholesterol concentration can be raised, but argues - in light of the fact that HDL-cholesterol concentration does not reflect the protective properties of HDL particles - that this approach is flawed and a different approach, targeting know antiatherosclerotic components of HDL, is required.

Comparison of the ability of paraoxonases 1 and 3 to attenuate the in vitro oxidation of low-density lipoprotein and reduce macrophage oxidative stress.

In light of recent conflicting results regarding the antiatherogenic properties of the paraoxonase (PON) multigene family we have reexamined these properties in vitro. The abilities of recombinant human PON1 and PON3 to retard LDL oxidation, prevent macrophage oxidative stress, and promote macrophage cholesterol efflux were investigated. Both PON1 and PON3 retarded the oxidation of LDL; PON1 was significantly more efficient (50 and 100% at 20 microg PON3 and PON1, respectively (P<0.

Effect of fenofibrate therapy on paraoxonase1 status in patients with low HDL-C levels.

Objectives: We evaluated the effect of micro-coated fenofibrate on lipid parameters, high sensitivity C-reactive protein and paraoxonase1 levels in dyslipidemic patients with low high-density lipoproteins levels. In addition, the effects of the paraoxonase1 polymorphisms on lipid and paraoxonase1 responses to fenofibrate therapy were examined.

Methods: A total of 61 dyslipidemic patients with low high-density lipoproteins levels were recruited into this study to receive micro-coated fenofibrate (160 mg/day) for 12 weeks.