Plasma Paraoxonase Research Articles

Lecithin-cholesterol acyltransferase and paraoxonase-1 levels in atherosclerotic cardiovascular disease patients in Nigeria.

Recent evidence has linked changes in plasma lecithin-cholesterol acyltransferase (LCAT) and paraoxonase-1 (PON-1) levels with increased risk for development of premature atherosclerotic cardiovascular disease (ASCVD) in different populations. However, studies on this in Nigeria and sub-Saharan Africa are scarce. This study assessed the association between reduced plasma LCAT and PON-1 levels and an increased risk of ASCVD, and their potential as biomarkers for ASCVD. Atherosclerotic cardiovascular disease patients and healthy controls were randomly selected for this cross-sectional case-control study from the Lagos State University Teaching Hospital, Ikeja, Lagos, Nigeria, between March 2022 and March 2023. Plasma LCAT and PON-1 were determined by sandwich enzyme-linked immunosorbent assay, while the lipid profile was measured by spectrophotometry. A total of 153 ASCVD patients (mean age: 52.92 ± 10.24 years) and 50 healthy controls (mean age: 46.96 ± 11.05 years) were included in the analyses. Stastistically significant increases were observed in the mean body weight, hip circumference, waist circumference, waist-to-hip ratio, body mass index, diastolic and systolic blood pressure (all p ≤ 0.001), and pulse rate (p = 0.003) compared to the control values. Statistically significant increases were also observed in the mean plasma total cholesterol, triglycerides, low-density lipoprotein cholesterol, and non-high-density lipoprotein cholesterol (all p ≤ 0.001). In contrast, the mean plasma high-density lipoprotein cholesterol, LCAT, and PON-1 (p ≤ 0.001) were notably reduced compared to the control values. The present study provides supportive evidence that changes in plasma LCAT and PON-1 could predispose individuals to risk of premature ASCVD. Plasma LCAT and PON-1 may serve as independent markers or complement other established cardiovascular disease markers to discriminate the risk of ASCVD when it is unclear.

The protective effect of caffeic acid phenethyl ester on cadmium-induced liver toxicity: A histopathological and biochemical study

In this study, the changes caused by caffeic acid phenethyl ester (CAPE) in the histopathological and biochemical parameters in the oxidant / antioxidant balance in mice with experimental cadmium toxicity were investigated. A total of 40 female Swiss albino mice were used, with 10 mice in each group. The mice were divided into four groups (Group I - Control group, Group II - CAPE group, Group III - Cadmium group, Group IV - Cadmium + CAPE group). Plasma paraoxonase (PON) activity, high-density lipoprotein (HDL), low-density lipoprotein (LDL), total sialic acid (TSA), total antioxidant capacity (TAC), total oxidant capacity (TOC), and oxidative stress index (OSI) were analyzed on mice’s blood samples. The results showed that cadmium intoxication triggered oxidative stress in the mice. It also lowered their PON activity alongside TAC and HDL levels (P<0.001, P<0.01, and P<0.01, respectively) and increased their TSA, LDL, TOC, and OSI levels (P<0.05, P<0.01, P<0.01, and P<0.01, respectively). The histopathological examination of the liver tissues revealed focal apoptotic regions, sinusoidal occlusion, and irregularity in the cadmium group and no significant change in the other groups. These results indicated that CAPE can significantly prevent biochemical and histopathological changes due to cadmium damage.

Vutiglabridin Modulates Paraoxonase 1 and Ameliorates Diet-Induced Obesity in Hyperlipidemic Mice.

Vutiglabridin is a clinical-stage synthetic small molecule that is being developed for the treatment of obesity and its target proteins have not been fully identified. Paraoxonase-1 (PON1) is an HDL-associated plasma enzyme that hydrolyzes diverse substrates including oxidized low-density lipoprotein (LDL). Furthermore, PON1 harbors anti-inflammatory and antioxidant capacities and has been implicated as a potential therapeutic target for treating various metabolic diseases. In this study, we performed a non-biased target deconvolution of vutiglabridin using Nematic Protein Organisation Technique (NPOT) and identified PON1 as an interacting protein. We examined this interaction in detail and demonstrate that vutiglabridin binds to PON1 with high affinity and protects PON1 against oxidative damage. Vutiglabridin treatment significantly increased plasma PON1 levels and enzyme activity but not PON1 mRNA in wild-type C57BL/6J mice, suggesting that vutiglabridin modulates PON1 post-transcriptionally. We further investigated the effects of vutiglabridin in obese and hyperlipidemic LDLR-/- mice and found that it significantly increases plasma PON1 levels, while decreasing body weight, total fat mass, and plasma cholesterol levels. Overall, our results demonstrate that PON1 is a direct, interacting target of vutiglabridin, and that the modulation of PON1 by vutiglabridin may provide benefits for the treatment of hyperlipidemia and obesity.

Plasma paraoxonase-1 activity levels in patients with type 2 diabetes mellitus in Lagos State University Teaching Hospital, Lagos, Southwest Nigeria: a cross-sectional study.

paraoxonase 1 (PON1) is a high-density lipoprotein (HDL) associated enzyme that has anti-inflammatory, anti-atherogenic, and antioxidant functions. PON1 is noted to be a determinant of resistance to the development of atherosclerosis through hydrolysis of phospholipid and cholesteryl ester hydroperoxides. This study was designed to assess PON1 activity levels among patients with type 2 diabetes mellitus (T2DM) in Southwest Nigeria. this was a cross-sectional study done over a period of six months. A total of 138 participants; 69 with T2DM and 69 apparently healthy controls were recruited for this study. Fasting plasma glucose (FPG), HDL cholesterol (HDL-c), and PON1 activity were analyzed in the participants. The comparison of the mean between the groups of participants was assessed using the independent student t-test while the Mann-Whitney U test was used to compare two medians. The p-value was set at 0.05. mean age for participants with T2DM was 54.90 ± 8.1 years and the healthy control group was 54.12 ± 8.4 years, with a p-value of 0.549. The male-to-female ratio was 0.47 for both participants with T2DM and healthy controls. Participants with T2DM had significantly higher median glucose concentration of 109.18 mg/dl compared with 82.58 mg/dl among controls, p-value <0.001. Median serum HDL-c was lower in diabetics compared to controls (52.66 mg/dl vs 57.92 mg/dl; p-value < 0.001). PON1 activity was lower in T2DM compared with that of the controls (690.11 pmol/min/ml vs 3379.7 pmol/min/ml; p-value <0.001). Paroxonase 1 showed a non-significant positive correlation with HDL-c and a negative correlation with FPG, and body mass index (BMI). these findings suggest that PON1 activity is lower in T2DM compared to healthy controls and a lower PON1 activity level was seen among female diabetics compared with the male diabetics.

Paraoxonase 1 Ameliorates Renal Lipotoxicity by Activating Lipophagy and Inhibiting Pyroptosis

Several studies in recent years have shown that lipid overload causes lipotoxic damage to the kidney, and oxidative stress, inflammation, and autophagic arrest are all important mechanisms of renal lipotoxicity. However, effective measures with therapeutic effects on renal lipotoxicity are limited. The present study indicated the protective effect of the paraoxonase 1 (PON1) against renal lipotoxicity in high-fat diet-fed scavenger receptor class B type I-deficient (SR-BI-/-) mice. The results showed that SR-BI-/- mice exhibited significant renal pathologic characteristics, such as oxidative stress, inflammation, and fibrosis, under a normal chow diet, and were accompanied by dyslipidemia and reduced plasma PON1 activity and renal PON1 levels. PON1 overexpression significantly attenuated the above pathologic changes in the kidneys of SR-BI-/- mice fed with a high-fat diet. Mechanistically, PON1 may ameliorate renal oxidative stress by reducing reactive oxygen species production, reduce renal lipid accumulation by inhibiting AKT/mechanistic target of rapamycin kinase pathway to activate lipophagy, and reduce the occurrence of inflammation and cell death by inhibiting Nod-like receptor family protein 3 inflammasome-mediated pyroptosis. The present study is the first to show that PON1 overexpression can effectively alleviate renal lipotoxicity injury, and PON1 may be a promising therapeutic strategy for the treatment of renal lipotoxicity-related diseases.

Effects of combined physical exercise on plasma lipid variables, paraoxonase 1 activity, and inflammation parameters in adults with obesity: a randomized clinical trial.

We aimed to investigate whether combined physical exercise mayaffect plasma lipid variables, paraoxonase 1 (PON1) activity, and inflammation parameters in adults with obesity. Thirty-six participants were recruited to complete the study protocol. The mean age was 37 ± 1years, and the baseline body mass index was 33.0 ± 0.4kg/m2. Participants were allocated to the control group (CG) and the exercise group (EG). The EG performed three weekly sessions of combined physical exercise for 16weeks. Plasma lipid variables, PON1 activity, and inflammatory profile were determined before and after intervention. Total cholesterol levels decreased in both groups, without intergroup difference (time p = 0.001). Non-high-density lipoprotein cholesterol (HDL-C) levels decreased in both groups (time p = 0.001); however, they were lower in the EG than in the CG (p = 0.038). The EG had increased HDL-C levels, but the CG had decreased HDL-C levels (time*group p = 0.011). PON1 activity was reduced in both groups (time, p = 0.001). The Castelli risk Index I and II reduced in the EG and increased in the CG (time*group, p = 0.008 and p = 0.011, respectively). The inflammatory markers were not modified. Adults with obesity may benefit from regular practice of combined physical exercise training in many metabolic aspects that are related to protection against the development of cardiovascular disease.

Polymorphism rs4673 and plasma paraoxonase 1 level for prediction and early diagnosis of anthracycline-mediated cardiotoxicity in patients with breast cancer.

12077 Background: Anthracyclines are highly effective chemotherapeutic agents, used for a wide variety of malignancies. Despite their antitumor efficacy there is a risk of cardiotoxic manifestations that reduce the time and quality of life of patients. The purpose was to study the effectiveness of molecular genetic tests based on rs4673 CYBA genotyping (c.242C &gt; T) and measurement of plasma paraoxonase 1 (PON1) level in patients with breast cancer (BC) for predicting and diagnosing anthracycline-mediated cardiotoxicity (AMC). Methods: The study included 256 Caucasian patients (median age - 55 years) with a diagnosis of breast cancer normal cardiovascular system parameters at baseline, who were treated with anthracyclines in 2019-2020. For rs4673 genotyping, DNA was extracted from the blood by using DNA-sorb-B (AmpliSens, Russia). HRM-PCR was performed on a CFX96 amplifier (Bio-Rad, USA). The presence of polymorphism was confirmed by the Sanger method on a Genetic Analyzer 3500 (ABI, USA). The concentration of PON1 in blood plasma was measured at baseline and after 4 course of chemotherapy with anthracyclines using ELISA kits (Cloud-Clone Corp., China/USA). Results: During the follow-up period 21 (8.2%) patients developed signs of subacute (changes developed within several weeks after the last course of therapy) or early chronic AMC (changes developed within a year after completion of anthracycline therapy). In the group of patients without AMC the frequency of the minor allele rs4673 (c.214C &gt; T CYBA) was 0.38, the frequency of genotypes C/C was 0.4, C/T - 0.43, and T/T - 0.17. The risk of AMC increased by 6.49 times in the presence of the rs4673 polymorphic allele (p = 0.002). The area under the ROC curve of the test based on rs4673 genotyping was 71.9%. The concentration of PON1 after the 4 courses of chemotherapy increased by 19.57% in the group of patients without cardiotoxic manifestations (p = 0.018) and in the group of patients with AMC by 20.23% (p = 0.007) as compared to the initial level. Besides, after 4 courses of chemotherapy the PON1 level was higher in patients with AMC by 25.08% (p = 0.026) than in patients without cardiovascular complications. The sensitivity of the test based on the measurement of the PON1 level in the blood plasma after 4 courses of chemotherapy was 100%, the specificity was 70.8% with a cut-off value of 2.9 ng/ml. Conclusions: This study has showed that genotyping of patients for the rs4673 polymorphism allows pre-stratification of the risk group white determination of the PON1 level in blood plasma after 4 courses of chemotherapy gives the opportunity to identify patients with AMC and promptly correct the chosen treatment.

Inhibition of lipid peroxidation and free radical scavenging activities of methanolic leaf extract of Psidium guajava

Objectives: Studies have linked the generation of free radicals with the incidence of degenerative diseases. Antioxidants from plant origin have been proved to play a major role in mitigating against free radicals-induced oxidative damage. This study aimed at assessing the in-vitro and in-vivo antioxidant capability of Psidium guajava leafMethods: The leaves were collected and extracted with 70% methanol. Total phenolic, and flavonoids contents, 2,2-diphenyl-1-picrylhydrazyl and Hydroxyl radicals scavenging activities, and inhibition of lipid peroxidation potential of the extract were assessed. Furthermore, rats (n=21) randomized into three groups were exposed to 50, 150, and 250 mg/kg body weight of the extract for 30 days. Control animals (n=7) received corn oil, after which blood and liver were excised for antioxidant assay.Results: The extract is rich in phenolic and flavonoid compounds. It scavenged DPPH and hydroxyl radicals and inhibits lipid peroxidation in-vitro. In-vivo, it increased the activities of hepatic superoxide dismutase, catalase, glutathione peroxidase, and plasma paraoxonase, and the concentration of hepatic reduced glutathione and MDA.Conclusion: Psidium guajava leaf extract is a potential source of natural antioxidant compounds, capable of supplementing the body's antioxidant defense system.

Iron chelation therapy with deferiprone improves oxidative status and red blood cell quality and reduces redox-active iron in β-thalassemia/hemoglobin E patients.

The oxidative status of twenty-three β-thalassemia/hemoglobin E patients was evaluated after administration of 75mg/kg deferiprone (GPO-L-ONE®) divided into 3 doses daily for 12 months. Serum ferritin was significantly decreased; the median value at the initial and final assessments was 2842 and 1719ng/mL, respectively. Progressive improvement with significant changes in antioxidant enzyme activity, including plasma paraoxonase (PON) and platelet-activating factor acetylhydrolase (PAF-AH), and in antioxidant enzymes in red blood cells (glutathione peroxidase (GPx), catalase and superoxide dismutase (SOD)) were observed at 3-6months of treatment. The levels of total GSH in red blood cells were significantly increased at the end of the study. Improved red blood cell membrane integrity was also demonstrated using the EPR spin labeling technique. Membrane fluidity at the surface and hydrophobic regions of the red blood cell membrane was significantly changed after 12 months of treatment. In addition, a significant increase in hemoglobin content was observed (6.6±0.7 and 7.5±1.3g/dL at the initial assessment and at 6 months, respectively). Correlations were observed between hemoglobin content, membrane fluidity and antioxidant enzymes in red blood cells. The antioxidant activity of deferiprone may partly be explained by progressive reduction of redox active iron that catalyzes free radical reactions, as demonstrated by the EPR spin trapping technique. In conclusion, iron chelation therapy with deferiprone notably improved the oxidative status in thalassemia, consequently reducing the risk of oxidative-related complications. Furthermore, the improvement in red blood cell quality may improve the anemia situation in patients.

Protective effect of astaxanthin on experimental ovarian damage in rats.

This study aimed to investigate the protective effect of astaxanthin (AS) on 3-nitropropionic acid (3-NPA) induced experimental ovarian damage in rats. Thirty two female Wistar rats were divided into four equal groups of eight each: control group (C); phosphate-buffered saline, AS group; AS (80 mg/kg) for 14 days, 3-NPA group; 3-NPA (6.25 mg/kg) twice a day for 7 days, 3-NPA + AS group; administered AS (80 mg/kg) for 14 days and 3-NPA (6.25 mg/kg) for 7 days. All injections were administered intraperitoneally. Rats were fed ad libitum with standard rat chow and tap water. Plasma and ovarian tissue total antioxidant capacity (TAC), total oxidant capacity (TOC) and oxidative stress index (OSI) levels, whole blood reduced glutathione (GSH), plasma paraoxonase 1 (PON1) activity, lipid profile, malondialdehyde (MDA), nitric oxide (NO), total sialic acid (TSA) and total thiol (TT) concentrations were analysed spectrophotometrically. Also, ovarian tissue histopathology was performed. We observed 3-NPA-induced histopathological ovarian damagesignificantly decreased the TAC (p < 0.001), GSH (p < 0.001), high-density lipoprotein (p < 0.01) levels and PON1 activity (p < 0.01), and significantly increased TOC, OSI (p < 0.001), MDA, NO, TSA, cholesterol, low-density lipoprotein (p < 0.01) and triglyceride (p < 0.05) levels. In conclusion, cotreatment with AS restored the negative effect of 3-NPA on all biochemical parameters cited above and improved the histopathological ovarian damage. Ovarian toxicity induced by 3-NPA might be due to oxidative damage. The improvement of AS seems to be related to its antioxidant properties.

Establishment of a sandwich ELISA for bovine plasma PON-1 and its predictive capabilities for dairy cows with fatty liver

The aim of this study to improve the clinical diagnosis of fatty livers (FL) in dairy cows by using the paraoxonase-1 (PON-1) enzyme as a detection index. Prokaryotic expression technology was used to generate recombinant bovine PON-1 protein. Mice were immunized with this protein to generate hybridoma cells, stably secreting anti-PON-1. Cells were injected into the peritoneal cavity of mice, and ascites were purified to generate bovine PON-1 monoclonal antibody. Rabbits were then immunized with this antigen, and a polyclonal antibody against bovine PON-1 was obtained. Using monoclonal and polyclonal antibodies, a double-antibody sandwich ELISA for plasma PON-1 was constructed. Plasma samples were collected from healthy (n = 13) and FL (n = 13) cows, and plasma PON-1 levels were detected using the PON-1 ELISA. Receiver operating characteristic curve (ROC) analysis was used to analyze correlations between PON-1 levels and FL. Results showed that the ideal working concentration of the monoclonal antibody was 0.8 mg/mL, and the quantitative detection limit was 90 ng/mL. Plasma PON-1 levels were significantly lower in FL cows, when compared with healthy animals. It is concluded that PON-1 ELISA predicts risk factors for dairy cows with FL. PON-1 levels in plasma can be used as an early warning indicator for FL and concentration of 61.87 nmol/L was identified as warning index.

Clusterin, paraoxonase 1, and myeloperoxidase alterations induce high-density lipoproteins dysfunction and contribute to peripheral artery disease; aggravation by type 2 diabetes mellitus.

Peripheral artery disease (PAD) is an atherosclerotic disorder affecting arteries of the lower limbs, the major risk factors including dyslipidemia and diabetes mellitus (DM). We aimed to identify alterations of the proteins in high-density lipoproteins (HDL) associated with HDL dysfunction in PAD patients. HDL2 and HDL3 were isolated from plasma of PAD patients with/without DM (PAD-DM/PAD) and healthy subjects (N). Apolipoprotein AI (ApoAI), ApoAII, ApoCIII, clusterin (CLU), paraoxonase 1 (PON1), myeloperoxidase (MPO), and ceruloplasmin (CP) were measured in HDL2 /HDL3 and plasma. Oxidation and glycation of the analyzed proteins were assessed as malondialdehyde-protein adducts (MDA) and advanced glycation end-products (AGE), respectively. The anti-inflammatory effect of HDL3 was estimated as its potential to reduce monocyte adhesion to tumor necrosis factor α-activated endothelial cells. We show that in PAD patients compared to N subjects: (i) HDL2 presented increased levels of MDA-PON1, AGE-PON1, AGE-ApoAI, ApoAII, ApoCIII, and CP levels, and decreased PON1 levels; (ii) HDL3 had increased levels of MDA- and AGE-CLU and -ApoAI, MDA-PON1, ApoCIII, CLU, MPO, CP, and reduced PON1 levels. All these alterations were exacerbated by DM. These changes were more pronounced in HDL3 , which had reduced anti-inflammatory potential in PAD and became pro-inflammatory in PAD-DM. In PAD patients' plasma, CLU levels and MPO specific activity increased, while PON1 specific activity decreased. In conclusion, HDL function is altered in PAD patients due to multiple modifications of associated proteins that are aggravated by DM. Plasma CLU, MPO, and PON1 could constitute indicators of HDL dysfunction and contribute to risk stratification in PAD patients.

Hepatic paraoxonase 1 ameliorates dysfunctional high-density lipoprotein and atherosclerosis in scavenger receptor class B type I deficient mice.

BackgroundHigh-density lipoprotein (HDL) plays an antiatherogenic role by mediating reverse cholesterol transport (RCT), antioxidation, anti-inflammation, and endothelial cell protection. Recently, series of evidence have shown that HDL can also convert to proatherogenic HDL under certain circumstances. Plasma paraoxonase 1 (PON1) as an HDL-bound esterase, is responsible for most of the antioxidant properties of HDL. However, whether PON1 can serve as a therapeutic target of dysfunctional HDL-related atherosclerosis remains unclear.MethodsIn this study, scavenger receptor class B type I deficient (Scarb1−/−) mice were used as the animal model with dysfunctional HDL and increased atherosclerotic susceptibility. Hepatic PON1 overexpression and secretion into circulation were achieved by lentivirus injection through the tail vein. We monitored plasma lipids levels and lipoprotein profiles in Scarb1−/− mice, and measured the levels and activities of proteins associated with HDL function. Meanwhile, lipid deposition in the liver and atherosclerotic lesions was quantified. Hepatic genes relevant to HDL metabolism and inflammation were analyzed.ResultsThe results showed the relative levels of PON1 in liver and plasma were increased by 1.1-fold and 1.6-fold, respectively, and mean plasma PON1 activity was increased by 63%. High-level PON1 increased the antioxidative and anti-inflammatory properties, promoted HDL maturation and macrophage cholesterol efflux through increasing HDL functional proteins components apolipoprotein A1 (APOA1), apolipoprotein E (APOE), and lecithin-cholesterol acyltransferase (LCAT), while decreased inflammatory protein markers, such as serum amyloid A (SAA), apolipoprotein A4 (APOA4) and alpha 1 antitrypsin (A1AT). Furthermore, hepatic PON1 overexpression linked the effects of antioxidation and anti-inflammation with HDL metabolism regulation mainly through up-regulating liver X receptor alpha (LXRα) and its downstream genes. The pleiotropic effects involved promoting HDL biogenesis by raising the level of APOA1, increasing cholesterol uptake by the liver through the APOE-low density lipoprotein receptor (LDLR) pathway, and increasing cholesterol excretion into the bile, thereby reducing hepatic steatosis and aorta atherosclerosis in Western diet-fed mice.ConclusionsOur study reveals that high-level PON1 improved dysfunctional HDL and alleviated the development of atherosclerosis in Scarb1−/− mice. It is suggested that PON1 represents a promising target of HDL-based therapeutic strategy for HDL-related atherosclerotic cardiovascular disease.

Influence of phospholipase A2 and paraoxonase activity on endothelial function changes in various forms of coronary artery disease

Abstract Funding Acknowledgements Type of funding sources: None. High phospholipase A2 activity is associated with atherosclerotic disorders of the arteries, while paraoxonase activity decreases with increasing atherogenic plasma activity. The purpose is to study the relationship between the combined effect of phospholipase A2 and paraoxonase activity on vascular endothelial dysfunction in various forms of coronary artery disease. We examined 152 men 52.5 ± 0.8 years, including 53 - STEMI, 32 - NSTEMI, 67 - chronic chronic coronary syndromes (CCS). Methods. All patients were examined for endothelial function of the brachial artery with a test for reactive hyperemia and vasodilation with exogenous NO, as well as determination of phospholipase A2 activity and plasma paraoxonase activity. All studiies conform to the principles of the Declaration of Helsinki of the World Medical Association. Results. Dynamics evaluation of endothelial function indicates a significant increase in blood flow in the brachial artery after compression in the NSTEMI group, but a decrease in the STEMI group after vasodilation of exogenous NO. Analysis of phospholipase A2 activity and paraoxonase showed an increasing the first in STEMI group compared to NSTEMI one and CCS while decreasing the second in the corresponding groups (Tab. 1). The results of the study confirm the association of increased activity of phospholipase A2 with vascular disorders severity, the correction of which should be considered a priority in prospective studies. The fact of reducing the activity of paraoxonase should be considered in the correction treatment of vascular disorders. Tab. 1 CCS NSTEMI STEMI LSD criteria D% 7,48 ± 0,39 6,65 ± 0,54 6,77 ± 0,62 {1-2} V% 54,71 ± 1,01 51,13 ± 1,92 42,16 ± 3,29 p1 &amp;lt; 0,0001 p2 = 0,010 {3} / {1, 2} D% (NO) 10,35 ± 0,47 8,24 ± 0,96 10,28 ± 0,98 {1, 2} V% (NO) 55,60 ± 1,12 37,71 ± 3,72 p1 &amp;lt; 0,0001 28,12 ± 3,94 p1 &amp;lt; 0,0001 {1} / {2, 3} sPA2 1,12 ± 0,03 1,25 ± 0,04 p1 &amp;lt; 0,0001 1,34 ± 0,04 p1 &amp;lt; 0,0001 {1} / {2, 3} PAO 0,54 ± 0,01 0,50 ± 0,01 0,44 ± 0,01 p1 &amp;lt; 0,0001 p2 &amp;lt; 0,0001 {1} / {2,3} D% - diameter of brachial artery after compression. V% - blood flow velocity after compression. sPA2 -phospholipase A2. PAO - paraoxanase. p - reliability on Sheffe"s criteria.

Chronic nandrolone decanoate administration effects on antioxidant parameters in Wistar rats

Chronic nandrolone decanoate exposure is associated with a modified redox status in the favor of oxidants. Paraoxonase and myeloperoxidase activities are considered sensitive biomarkers of oxidative stress and inflammation, being also predictors for coronary artery disease. The aim of our study was to investigate the impact of chronic nandrolone administration on paraoxonase and myeloperoxidase activities in Wistar rats. 16 Wistar rats were divided into two groups (n=8 for each of them): nandrolone decanoate (A) treated group and control group (C). After 12 weeks of nandrolone decanoate administration we analyzed several plasma oxidative stress parameters: TROLOX Equivalent Antioxidant Activity, paraoxonase and myeloperoxidase activities, total thiols, and advanced oxidation protein products. Our results showed a significant decreased total antioxidant activity in nandrolone treated group compared with controls, while paraoxonase activity and total thiols levels were significantly increased. Myeloperoxidase activity and advanced oxidation protein products were not significantly different between the two studied groups. In conclusion decreased plasma total antioxidant activity suggested increased oxidative stress induced by chronic high doses of nandrolone. Despite oxidative stress presence high doses of nandrolone induced also increased plasma paraoxonase activity.

Paraoxonase-1 (PON1) Status Analysis Using Non-Organophosphate Substrates.

Human paraoxonase-1 (PON1) is a high-density lipoprotein-associated enzyme with antioxidant, anti-inflammatory, and antiapoptotic roles. The ability of PON1 to hydrolyze specific organophosphate (OP) compounds and prevent accumulation of oxidized lipids in lipoproteins has prompted a large number of studies investigating PON1's role in modulating toxicity and disease. Most of these studies, however, have only focused on PON1 single nucleotide polymorphism analyses and have ignored PON1 activity levels, arguably the most important parameter in determining protection against exposure and disease. We developed a two-substrate activity assay termed "PON1 status" that reveals both the functional PON1192 genotype and plasma PON1 activity levels. While our previous studies with PON1 status demonstrated that both PON1192 functional genotype and enzymatic activity levels obtained exclusively by determining PON1 status are required for a proper evaluation of PON1's role in modulating OP exposures and risk of disease, the original PON1 status assay requires the use of highly toxic OP metabolites. As many laboratories are not prepared to handle such toxic compounds and the associated waste generated, determination of PON1 status has been limited to rather few studies. Here, we describe a PON1 status protocol that uses non-OP substrates with a resolution equivalent to that of the original PON1 status approach. We have also included useful suggestions to ensure the assays can easily be carried out in any laboratory. The protocols described here will enable a proper examination of the risk of exposure or susceptibility to disease in PON1 epidemiological studies without the need to handle highly toxic substrates. © 2021 Wiley Periodicals LLC. Basic Protocol: Determining PON1 status using non-organophosphate substrates Support Protocol 1: Experimental pathlength determination Support Protocol 2: PON1 DNA genotyping for the Q192R (rs662) polymorphism.

Changes in fatty acids in plasma and association with the inflammatory response in dairy cows abomasally infused with essential fatty acids and conjugated linoleic acid during late and early lactation

Dairy cows are exposed to increased inflammatory processes in the transition period from late pregnancy to early lactation. Essential fatty acids (EFA) and conjugated linoleic acid (CLA) are thought to modulate the inflammatory response in dairy cows. The present study investigated the effects of a combined EFA and CLA infusion on the fatty acid (FA) status in plasma lipids, and whether changes in the FA pattern were associated with the acute phase and inflammatory response during late pregnancy and early lactation. Rumen-cannulated Holstein cows (n = 40) were assigned from wk 9 antepartum to wk 9 postpartum to 1 of 4 treatment groups. Cows were abomasally supplemented with coconut oil (CTRL, 76 g/d), linseed and safflower oil (EFA, 78 g/d of linseed oil and 4 g/d of safflower oil; ratio of oils = 19.5:1; n-6:n-3 FA ratio = 1:3), Lutalin (CLA, 38 g/d; isomers cis-9,trans-11 and trans-10,cis-12; each 10 g/d), or both (EFA+CLA). Blood samples were taken to measure changes in FA in blood plasma on d -63, -42, 1, 28, and 56, and in plasma lipid fractions (cholesterol esters, free fatty acids, phospholipids, and triglycerides) on d -42, 1, and 56 relative to calving, and in erythrocyte membrane (EM) on d 56 after calving. Traits related to the acute phase response and inflammation were measured in blood throughout the study. Liver samples were obtained for biopsy on d -63, -21, 1, 28, and 63 relative to calving to measure the mRNA abundance of genes related to the inflammatory response. The concentrations of α-linolenic acid and n-3 FA metabolites increased in lipid fractions (especially phospholipids) and EM due to EFA supplementation with higher α-linolenic acid but lower n-3 metabolite concentrations in EFA+CLA than in EFA treatment only. Concentration of linoleic acid decreased in plasma fat toward calving and increased during early lactation in all groups. Concentration of plasma arachidonic acid was lower in EFA- than in non-EFA-treated groups in lipid fractions and EM. The cis-9,trans-11 CLA increased in all lipid fractions and EM after both CLA treatments. Plasma haptoglobin was lowered by EFA treatment before calving. Plasma bilirubin was lower in EFA and CLA than in CTRL at calving. Plasma concentration of IL-1β was higher in EFA than in CTRL and EFA+CLA at certain time points before and after calving. Plasma fibrinogen dropped faster in CLA than in EFA and EFA+CLA on d 14 postpartum. Plasma paraoxonase tended to be elevated by EFA treatment, and was higher in EFA+CLA than in CTRL on d 49. Hepatic mRNA abundance revealed time changes but no treatment effects with respect to the inflammatory response. Our data confirmed the enrichment of n-3 FA in EM by EFA treatment and the inhibition of n-3 FA desaturation by CLA treatment. The elevated n-3 FA status and reduced n-6:n-3 ratio by EFA treatment indicated a more distinct effect on the inflammatory response during the transition period than the single CLA treatment, and the combined EFA+CLA treatment caused minor additional changes on the anti-inflammatory response.

Abstract 3946: HDL associated Paraoxonase 1 reduces the ovarian tumorigenesis by enhancing the HDL function

Abstract Background: Membrane lipids/cholesterol determines the fluidity, clustering of receptors and other protein interactions that delineate signaling pathways for cell cycle/proliferation. Emerging evidences suggest that highly proliferative cancer cells show a high lipid and cholesterol avidity and are considered as hallmarks of cancer aggressiveness including ovarian cancer. Paraoxonase 1 (PON1) is a high density lipoprotein (HDL) associated enzyme with a plethora of functions. PON1 deficiency aggravates HDL inflammatory index, systemic inflammation, and results in lipid retention associated diseases including atherosclerosis and hepatic steatosis. Meta-analysis studies documented that PON1 polymorphisms are associated with various cancers including ovarian cancer and PON1 activity is negatively correlated with human ovarian tumor size, providing clinical association between PON1 and ovarian cancers. Yet, the role and mechanism of action of PON1 in ovarian cancer development has not been elucidated. Hypothesis: We hypothesized that PON1 may inhibit the ovarian tumorigenesis by modulating HDL function. Methods and Results: In this report, in patients with ovarian cancer, we observed that plasma PON1 levels are higher, but with lower activity compared to healthy control. Immunoprecipitation of plasma PON1, followed by ELISA against oxidized lipids suggest that PON1 is oxidatively modified, specifically by 4-HNE. In addition, PON1 activity is negatively correlated with HDL pro-inflammatory index. Using a xenograft mouse model, we demonstrate that overexpression of PON1 prevents the development of ovarian cancer. HDL from xenograft transgenic mice shows less pro-inflammatory properties with increased cholesterol efflux efficiency from ovarian cancer cells. Mechanistically, PON1 impairs VEGF signaling in ovarian cancer cells by increasing cholesterol (Mitogenic factor) efflux, resulting in reduced dimerization of vascular endothelial growth factor receptor 2 (VEGF-2R) and VEGF-2R phosphorylation (angiogenic inducer) as well as downstream signaling pathways, including Akt and ERK1/2 which in turn reduce the cell proliferation and angiogenesis. Furthermore, cholesterol and VEGF levels are significantly lowered in the tumor microenvironment in PON1 transgenic mice but there are no changes in the gene expressions that are associated with either cholesterol synthesis or its degradation pathways. Conclusion: Taken together, we report for the first time that PON1 acts as a tumor suppressor of ovarian cancer by possibly reducing VEFG signaling and enhancing the HDL function, suggesting that activation of HDL associated PON1 might be a fruitful strategy to inhibit the ovarian tumor formation. Citation Format: Asokan Devarajan, Victor Grijalva, Dawoud Sulaiman, Feng Su, Ellen O'Connor, Robin Farias-Eisner, Srinivasa Reddy. HDL associated Paraoxonase 1 reduces the ovarian tumorigenesis by enhancing the HDL function [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3946.

Pentoxifylline mitigates renal glycoxidative stress in obese mice by inhibiting AGE/RAGE signaling and increasing glyoxalase levels

AimThe pharmacological properties of pentoxifylline have been re-evaluated, particularly in chronic kidney disease in diabetes, favored by its anti-inflammatory action. Definitive evidences of renal outcomes are lacking, which indicates the need for investigation of novel mechanisms of action of pentoxifylline. We postulated that components associated with the metabolism of advanced glycation end products (AGEs) may be modulated by pentoxifylline, which consequently decreases the detrimental effects of obesity on kidneys. Main methodsC57BL-6J mice were fed a high-fat diet for 14 weeks and treated with 50 mg/kg pentoxifylline during the last 7 weeks. Changes in the renal levels of AGE metabolism-associated components were investigated, with particular focus on the receptor for AGEs (RAGE), its downstream components, and components related to AGE detoxification, including glyoxalase 1 (GLO 1). Key findingsPentoxifylline reduced body weight gain, improved insulin sensitivity and glucose tolerance, downregulated biomarkers of glycoxidative stress, and enhanced plasma paraoxonase 1 activity. In the kidneys, pentoxifylline inhibited glomerular expansion, lipid deposition, reduced pro-inflammatory cytokine levels, and induced the activation of AMP-activated protein kinase. Pentoxifylline inhibited the renal accumulation of AGEs and reduced the levels of RAGE and its downstream components, and consequently mitigated oxidative stress and apoptosis. Pentoxifylline also increased the renal levels of GLO 1 and the activities of antioxidant enzymes. Urinary albumin levels were observed to be lowered, which reconfirmed the antialbuminuric effects of pentoxifylline. SignificanceThe novel mechanisms of action help explain the renoprotective effects of pentoxifylline and the attenuation of obesity-associated renal complications related to glycoxidative stress.

Improved diagnostic value by combining plasma PON1 level with tumor biomarkers in Colorectal Cancer patients.

The incidence of colorectal cancer (CRC) ranks third among all cancers in China and improvements in screening for CRC have an important impact on prevention and control of the disease. Paraoxonase 1 (PON1) is a calcium ion-dependent hydrolase that is widely distributed in tissue. Its diagnostic value in colorectal cancer has been reported, but the diagnostic value of combining PON1 with carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), carbohydrate antigen 12-5 (CA12-5) in colorectal cancer has not been evaluated. Experiments were carried out in a total of 284 CRC patients and 90 healthy controls. The primary cohort was randomly divided into training and validation sets. The levels of PON1 in plasma of CRC patients were significantly lower than that in the healthy controls (P < 0.001). It showed excellent diagnostic value with the AUC reaching 0.750 for the training set and 0.742 for the validation set. Furthermore, combining PON1 with CEA, CA12-5, CA19-9 could better classify CRC patients (AUC rising from 0.821, 0.716, 0.712 to 0.875, 0.817 and 0.814, respectively, in the training set, from 0.818, 0.581, 0.593 to 0.854, 0.770, and 0.772 in the validation set). In conclusion, PON1 can serve as a diagnostic biomarker for CRC and raise the sensitivity and specificity when incorporated with traditional tumor biomarkers.