Plasma Phospholipase A2 Research Articles

Homocysteine and Lp-PLA2 levels: Diagnostic value in coronary heart disease.

Coronary heart disease (CHD) is the leading cause of mortality worldwide. Identifying effective diagnostic markers and understanding risk factors is crucial for prevention and management. This study aimed to investigate the levels of homocysteine (Hcy) and lipoprotein-associated phospholipase A2 (Lp-PLA2) in human plasma and their roles in the diagnosis and prognosis of CHD. A retrospective study was conducted on 232 patients with CHD, divided into Acute Myocardial Infarction, unstable angina pectoris, and stable angina pectoris groups, and a control group of 75 healthy adults. Blood samples were analyzed for serum Hcy and Lp-PLA2 levels using the cycling enzyme method and ELISA method, respectively. Statistical analyses were performed to evaluate the risk factors, and diagnostic efficacy was assessed using receiver operating characteristic (ROC) curves. No significant differences in age and sex were observed between the study and control groups, whereas marked disparities in risk factors such as obesity, hypertension, diabetes, and hyperlipidemia were noted. Significant differences in serum Hcy and Lp-PLA2 levels were identified among the CHD subgroups. Univariate and multivariate logistic regression analyses revealed that Hcy, Lp-PLA2, hypertension, and hyperlipidemia were significant risk factors for CHD. The combined diagnostic Area Under the Curve (AUC) for Hcy and Lp-PLA2 was found to be higher than that when using them individually. This study identified the elevation of Hcy and Lp-PLA2 levels as independent risk factors for CHD, and their conjoint analysis significantly enhanced clinical diagnostic efficacy. These findings provide valuable insights for CHD diagnosis, treatment, and prevention, highlighting the importance of these markers in CHD management.

BoaγPLI: Structural and functional characterization of the gamma phospholipase A2plasma inhibitor from the non-venomous Brazilian snakeBoa constrictor.

Plasma in several organisms has components that promote resistance to envenomation by inhibiting specific proteins from snake venoms, such as phospholipases A2 (PLA2s). The major hypothesis for inhibitor’s presence would be the protection against self-envenomation in venomous snakes, but the occurrence of inhibitors in non-venomous snakes and other animals has opened new perspectives for this molecule. Thus, this study showed for the first time the structural and functional characterization of the PLA2 inhibitor from the Boa constrictor serum (BoaγPLI), a non-venomous snake that dwells extensively the Brazilian territory. Therefore, the inhibitor was isolated from B. constrictor serum, with 0.63% of recovery. SDS-PAGE showed a band at ~25 kDa under reducing conditions and ~20 kDa under non-reducing conditions. Chromatographic analyses showed the presence of oligomers formed by BoaγPLI. Primary structure of BoaγPLI suggested an estimated molecular mass of 22 kDa. When BoaγPLI was incubated with Asp-49 and Lys-49 PLA2 there was no severe change in its dichroism spectrum, suggesting a non-covalent interaction. The enzymatic assay showed a dose-dependent inhibition, up to 48.2%, when BoaγPLI was incubated with Asp-49 PLA2, since Lys-49 PLA2 has a lack of enzymatic activity. The edematogenic and myotoxic effects of PLA2s were also inhibited by BoaγPLI. In summary, the present work provides new insights into inhibitors from non-venomous snakes, which possess PLIs in their plasma, although the contact with venom is unlikely.

The relationship between clinical findings and Plasma Phospholipase A2 levels in snakebite patients

The relationship between clinical findings and Plasma Phospholipase A2 levels in snakebite patients

Effect of Increasing the Plasma Phospholipase A2 Mass on the Risk of Masked Hypertension in Humans

Background: Masked Hypertension (MHT) is associated with an increased risk for Cardiovascular Disease (CVD). The etiopathogenesis of MHT is thought to be affected by oxidative stress and vascular inflammation. This study aimed to analyze the relationships between Lipoprotein-Associated Phospholipase A2 (Lp-PLA2), a unique vascular inflammation marker, with blood pressure variation and traditional risk factors in patients with MHT, and to determine the clinical significance. Methods: One hundred eighty-three patients without any prior therapeutic medications were included and divided into the following three groups: MHT (n=82); True Hypertension (THT) [n=52]); and normotensive (n=59). An Ambulatory Blood Pressure Monitor (ABPM) was used. Clinical biochemical parameters and the Lp-PLA2 mass in each group were measured, and the related clinical characteristics and risk factors for CVD were statistically analyzed. Results: The level of Lp-PLA2 in MHT group was significantly higher than the normotensive (191.8 ± 62.58 vs.108.3 ± 44.74 ng/ml, p<0.01) and true hypertension groups (191.8 ± 62.58 vs. 169.3 ± 54.55 ng/ml, p<0.05). Furthermore, the incidence of MHT was correlated with the increase in Lp-PLA2, around 65% of MHT patients with a Lp-PLA2 level ≥ 225 μ mol/L. The Lp-PLA2 level had a positive correlation with ABPM measurements, office-measured systolic blood pressure, and serum Uric Acid (UA) and Low-Density Lipoprotein Cholesterol (LDL-C) levels, but a negative correlation with the High-Density Lipoprotein Cholesterol (HDL-C) level. Conclusion: An increased LP-PLA2 level was closely associated with the metabolic stress and incidence of MHT, thus exhibit an important role in the pathophysiology and diagnostic assessment of MHT.

Structural and functional characterization of the phospholipase A2 plasma inhibitor (PLI) from Boa constrictor

Structural and functional characterization of the phospholipase A2 plasma inhibitor (PLI) from Boa constrictor

Aerobic exercise combined with mild to moderate circulatory resistance exercise can improve blood pressure variability and other circulatory indexes of persons with hypertension

Objective To observe the effect of aerobic exercise combined with impedance training on the blood pressure variability and other blood-related indexes of patients with hypertension. Methods Ninety patients with essential hypertension were randomly divided into group A, group B and group C, each of 30. All were treated with conventional anti-hypertensive drugs. Groups B and C additionally underwent 40 minutes of aerobic training and group C also received resistance training. There were 3 training sessions a week for 12 weeks. Each subject′s 24 h systolic blood pressure (24hSBP), 24 h diastolic blood pressure (24hDBP) and their standard deviations were observed before and after the 12 weeks. Blood indexes were examined and a plasma arteriosclerosis index was calculated. Results Before the treatment, there were no significant differences in any of the average measurements among the three groups. After the treatment, the average 24hSBP and 24hDBP of all three groups had decreased significantly, but larger decreases were observed in groups B and C. Compared with group B, the average 24hSBP and 24hDBP of group C had decreased significantly more. The average levels of atherogenic index of plasma (AIP) and lipoprotein phospholipase A2 of groups B and C were significantly lower than before the treatment and also significantly lower than group A′s average. The decrease in group C was significantly greater than in group B. Conclusions Anti-hypertensive drugs can lower blood pressure, but cannot effectively control blood pressure variation, reduce blood lipids or improve the arteriosclerosis index. Long-term, regular aerobic exercise can decrease these indicators and reduce cardiovascular disease risk in elderly patients with hypertension. Aerobic exercise combined with mild to moderate circulatory resistance exercise is more effective than aerobic exercise alone. Key words: Aerobic exercise; Resistance training; Hypertension; Blood pressure variability; Arteriosclerosis; Lipoprotein phospholipase A2

Consumption of plant extract supplement reduces platelet activating factor-induced platelet aggregation and increases platelet activating factor catabolism: a randomised, double-blind and placebo-controlled trial.

Platelet-activating factor (PAF) is a potent mediator of inflammation that plays a crucial role in atherosclerosis. The purpose of this study was to evaluate the effect of a dietary supplement containing mainly plant extracts on PAF actions and metabolism in healthy volunteers. A double-blind, placebo-controlled, 8 weeks' duration study was performed. Healthy volunteers were randomly allocated into the supplement or the placebo group and fifty-eight of them completed the study. The supplement contained plant extracts (Aloe gel, grape juice, Polygonum cuspidatum) and vitamins. The activities of PAF metabolic enzymes: the two isoforms of acetyl-CoA:lyso-PAF acetyltransferase, cytidine 5'-diphospho-choline:1-alkyl-2-acetyl-sn-glycerol cholinephosphotransferase (PAF-cholinephosphotransferase) and platelet-activating factor-acetylhydrolase (PAF-AH) in leucocytes and lipoprotein associated phospholipase-A2 in plasma were measured along with several markers of endothelial function. Platelet aggregation against PAF, ADP and thrombin receptor activating peptide was measured in human platelet-rich plasma by light transmission aggregometry. No difference was observed on soluble vascular cell adhesion molecule-1, sP-selectin and IL-6 levels at the beginning or during the study period between the two groups. Concerning PAF metabolism enzymes' activity, no difference was observed at baseline between the groups. PAF-AH activity was only increased in the supplement group at 4 and 8 weeks compared with baseline levels. In addition, supplement consumption led to lower platelet sensitivity against PAF and ADP compared with baseline levels. However, a trial effect was only observed when platelets were stimulated by PAF. In conclusion, supplementation with plant extracts and vitamins ameliorates platelet aggregation primarily against PAF and secondarily against ADP and affects PAF catabolism by enhancing PAF-acetylhydrolase activity in healthy subjects.

Plasma Lipid Metabolism is altered in Acute Mild Traumatic Brain Injury

Background and ObjectivesLipids are the source of signaling and inflammatory molecules that may contribute to trauma pathology. Accordingly, we examined levels of lipid species and a lipolytic enzyme activity in a one‐month longitudinal study of acute mild traumatic brain injury (mTBI).MethodsWe recruited mTBI patients (n=21) and non‐head trauma controls (CT, n=9), aged 18–50 years from the emergency department of the Huntington Memorial Hospital (Pasadena, CA). Symptom progression was observed within days of injury (W1), and four weeks thereafter (W4). Plasma lipids collected at W1 and W4 were extracted and unesterified (UFA) and esterified fatty acids (EFA) quantified using negative ion/chemical ionization gas chromatography/mass spectrometry. Plasma glycerophospholipids (GP) and sphingolipids (SP) were analyzed using liquid chromatography‐tandem mass spectrometry. Plasma phospholipase A2 (PLA2) activity was determined using a fluorescence‐based activity assay.ResultsmTBI participants' plasma at W1 had higher levels of 24 UFA species that included seven saturated fatty acids (SAFA), seven monounsaturated fatty acids (MUFA), four omega‐3, and six omega‐6 polyunsaturated fatty acids (PUFA). The sum of all SAFAs, MUFAs, omega‐3 PUFAs, omega‐6 PUFAs, and PUFAs were higher in mTBI plasma at W1. For EFA at W1, two omega‐6 (homo‐g‐C20:3n‐6, C22:4n‐6), one omega‐3 (C20:5n‐3), the sum of omega‐3 PUFAs, and the omega‐3 to omega‐6 ratios (omega‐3 index) were lower in mTBI than in CT. At W4, esterified C19:0 and C22:3n‐3 levels were lower while C24:1 was higher in mTBI compared with CT. The UFA to EFA ratio that estimates endogenous lipolysis of fatty acids was higher in mTBI than CT for three SAFAs, two MUFAs, two omega‐6, two omega‐3, and the ratio of the sum of UFAs to the sum EFAs. Calcium‐dependent PLA2 activity was higher in mTBI plasma at W1 but not at W4. mTBI PLA2 activity at W1 positively correlated with most UFA species except C18:2n‐6 and C18:3n‐6 but correlated only with two UFA (C20:1, C22:1) in CT. PLA2 activity negatively correlated with seven EFA species.ConclusionsOur data showing higher UFA, UFA to EFA ratios, and correlation of UFA with PLA2 indicate excessive lipolysis in early mTBI. A lower omega‐3 index suggests the excessive oxidative breakdown of omega‐3 in mTBI. We propose that early intervention using strategies that reduce lipolysis may attenuate tissue damage linked to mTBI. Additionally, measurements of fatty acid fluctuations may be useful in discovering new therapies and monitoring resolution of mTBI.Support or Funding InformationFinancial support provided by the D.O.D. grant W81XWH‐13‐1‐0005. Thao Tran, David Strickland, Betty Chung, Darlene Royal, and David Buennagel assisted with data collection and patient recruitment.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Plasma phospholipase A2 activity may serve as a novel diagnostic biomarker for the diagnosis of breast cancer.

Previous studies have indicated that phospholipase A2 (PLA2) may be associated with tumorigenesis in human tissues. The present study aimed to investigate the association between plasma PLA2 activity and the breast cancer (BC) status of patients. Increased plasma PLA2 activity was detected in patients with breast cancer when compared with healthy controls. Plasma samples were obtained from patients with BC (n=169), patients with benign disease (BD; n=80) and healthy controls (n=81). PLA2 activity was assessed using a quantitative fluorescent assay with selective inhibitors. It was demonstrated that increased PLA2 and secretory PLA2 (sPLA2) activity was associated with tumor stage, particularly in patients with late-stage disease. Additionally, smoking, alcohol consumption, body mass index (BMI) and age of patients did not have a significant effect on PLA2 activity. Analysis of receiver operating characteristic curves revealed that plasma PLA2 and sPLA2 activities were increased in BC patients compared with healthy controls. It was concluded that plasma PLA2 activity may serve as a biomarker for patients with BC.

Endothelial Dysfunction in Children With Obstructive Sleep Apnea Is Associated With Elevated Lipoprotein-Associated Phospholipase A2 Plasma Activity Levels.

BackgroundObstructive sleep apnea (OSA) is a highly prevalent condition, especially in obese children, and has been associated with increased risk for endothelial dysfunction and dislipidemia, which are precursors of atherosclerosis. Lipoprotein‐associated phospholipase A2 (Lp‐PLA2) is recognized as an independent risk factor for cardiovascular risk and atheromatous plaque activity. We hypothesized that Lp‐PLA2 levels would be elevated in children with OSA, particularly among obese children who also manifest evidence of endothelial dysfunction.Methods and ResultsOne hundred sixty children (mean age 7.1±2.3 years), either nonobese with (n=40) and without OSA (n=40) or obese with (n=40) and without OSA (n=40) underwent overnight polysomnographic and postocclusive reperfusion evaluation and a fasting blood draw the morning after the sleep study. In addition to lipid profile, Lp‐PLA2 plasma activity was assessed using a commercial kit. Obese children and OSA children had significantly elevated plasma Lp‐PLA2 activity levels compared to controls. Furthermore, when both obesity and OSA were concurrently present or when endothelial function was present, Lp‐PLA2 activity was higher. Treatment of OSA by adenotonsillectomy resulted in reductions of Lp‐PLA2 activity (n=37; P<0.001).ConclusionsLp‐PLA2 plasma activity is increased in pediatric OSA and obesity, particularly when endothelial dysfunction is present, and exhibits decreases on OSA treatment. The short‐term and long‐term significance of these findings in relation to cardiovascular risk remain undefined.

Lipid metabolites of the phospholipase A2 pathway and inflammatory cytokines are associated with brain volume in paediatric cerebral malaria.

BackgroundCerebral malaria (CM) remains a significant cause of morbidity and mortality in children in sub-Saharan Africa. CM mortality has been associated with increased brain volume, seen on neuroimaging studies.MethodsTo examine the potential role of blood metabolites and inflammatory mediators in increased brain volume in Malawian children with CM, an association study was performed between plasma metabolites, cytokine levels and phospholipase A2 (PLA2) activity with brain volume.ResultsThe metabolomics analysis demonstrated arachidonic acid and other lysophospholipids to be positively associated with brain swelling. These lipids are products of the PLA2 enzyme and an association of plasma PLA2 enzymatic activity with brain swelling was confirmed. TNFα, which can upregulate PLA2 activity, was associated with brain volume. In addition, CCL2 and IL-8 were also associated with brain volume. Some of these cytokines can alter endothelial cell tight junction proteins and increase blood brain barrier permeability.ConclusionsTaken together, paediatric CM brain volume was associated with products of the PLA2 pathway and inflammatory cytokines. Their role in causality is unknown. These molecules will need to undergo testing in vitro and in animal models to understand their role in processes of increased brain volume. These observations provide novel data on host physiology associated with paediatric CM brain swelling, and may both inform pathogenesis models and suggest adjunct therapies that could improve the morbidity and mortality associated with paediatric CM.Electronic supplementary materialThe online version of this article (doi:10.1186/s12936-015-1036-1) contains supplementary material, which is available to authorized users.

Relationship between plasma phospholipase A2 concentrations and lipoprotein subfractions in patients with stable coronary artery disease

BackgroundBoth increased lipoprotein-associated phospholipase A2 (Lp-PLA2) concentrations and atherogenic lipoprotein subfractions have been shown to reflect unfavourable cardiovascular risk. However, the correlation between Lp-PLA2 and lipoprotein subfractions in patients with coronary artery disease (CAD) has not been assessed yet. MethodsA total of 324 consecutive subjects who were not treated with lipid-lowering drugs were enrolled (angiographically proven CAD: n=253; non-CAD: n=71). Plasma Lp-PLA2 concentrations were measured using ELISA. The low-density lipoprotein (LDL) and high-density lipoprotein (HDL) subfractions were determined by Lipoprint System. ResultsPlasma Lp-PLA2 concentrations were higher in patients with CAD compared with those without CAD (153.61±78.73 vs. 131.41±65.49ng/ml, p=0.028). The univariable correlation analysis revealed that Lp-PLA2 concentrations were positively correlated with the cholesterol concentrations of each LDL subfractions and the intermediate as well as small HDL subfractions, while negatively linked with the LDL particle size and large HDL-cholesterol (HDL-C) concentrations in CAD group. However, no similar results were observed in the non-CAD group. Furthermore, multivariable regression analysis was performed in patients with CAD and showed that plasma Lp-PLA2 concentrations were independently correlated with the cholesterol concentrations of each LDL subfractions [large LDL-cholesterol (LDL-C): β=0.263, p<0.001; intermediate LDL-C: β=0.327, p<0.001; small LDL-C: β=0.135, p=0.033] and small HDL-C (β=0.133, p=0.034). ConclusionLp-PLA2 concentrations were positively associated with all LDL subfractions and small HDL subfraction, suggesting an interaction between Lp-PLA2 and lipoprotein subfraction phenotypes in the status of CAD.

PM212 Change in plasma phospholipase A2 mass and activity in subjects undergoing elective coronary stenting

PM212 Change in plasma phospholipase A2 mass and activity in subjects undergoing elective coronary stenting

Fatty acid and phospholipase A2 plasma levels in children with autism.

To evaluate fatty acid plasma levels, phospholipase A2 activity, and the developmental profiles of children with autism vs. control subjects. Twenty four children with autism underwent laboratory analysis for fatty acid quantification using gas chromatography and PLA2 activity determination by fluorometric assay. No correlation was observed between the developmental quotient and fatty acid plasma levels. Phospholipase A2 activity was significantly higher among autistic children compared with controls. The study did not show a correlation between fatty acid and phospholipase A2 plasma levels and the developmental profile of children with autism.

Effect of magnesium isoglycyrrhizinate on PLA2 during liver tissue injury following limb ischemia/reperfusion in rats

To investigate the effects of magnesium isoglycyrrhizinate (MI) on the changes of phospholipase A2 (PLA2) induced during liver tissue injury following limb ischemia/reperfusion (I/R) in rats. Twenty-four healthy male Sprague-Dawley rats weighing (230+/-30) g were randomly divided into three groups (n = 8 each) as follows: control (Group C: anesthetization without any ischemia); I/R injury (Group I/R: 4 h ischemia induced by rubber band ligation of the left hind limb around the roots of the hind limb, followed by 6 h of reperfusion, with 1 mL normal saline given via tail vein prior to reperfusion); MI-treated group (Group MI: underwent ischemia and reperfusion, with 1 mL MI (30 mg/kg) infused prior to reperfusion). Levels of TNFa and PLA2 in plasma and liver tissue were measured by enzyme-linked immunosorbent assay (ELISA). Levels of plasma alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), creatine kinase (CK), myeloperoxidase (MPO), and malondialdehyde (MDA), and activities of MPO and MDA in liver tissue were measured by colorimetry. Ultrastructural changes of liver tissue were observed by electron microscopy. The MI group had significantly lower PLA2 and TNFa in liver homogenates and serum than the I/R group (both P less than 0.05). Serum ALT, AST, LDH, and CK were significantly lower in the MI group than in the I/R group (all P less than 0.05), as were the levels of MPO and MDA in liver homogenates and serum (all P less than 0.05). The I/R group showed significantly more liver tissue damage, which appeared to be attenuated in the MI group. MI treatment can inhibit the I/R-induced TNFa, PLA2, and MDA in plasma and liver tissue, as well as decrease the I/R-induced MPO activity in rats. Thus, MI may have protective effects against liver tissue injury following limb ischemia/reperfusion.

Abstract 490: Distribution of Oxidized Phospholipids and Lipoprotein-Associated Phospholipase A2 in Plasma, Density Gradient Fractions and Individual Lipoproteins in Patients with Familial Hypercholesterolemia: Effect of LDL Apheresis

Objectives: Lipoprotein(a)[Lp(a)] is a causal, genetic risk factor for cardiovascular disease(CVD) and is enriched in pro-inflammatory oxidized phospholipids(OxPL) and lipoprotein-associated phospholipase A2(Lp-PLA2). Epidemiologic outcome studies have shown that the OxPL, Lp(a) and Lp-PLA2 collectively mediate additive risk for CVD. Methods: To derive insights into the relationships between Lp(a), OxPL and Lp-PLA2, 18 patients with familial hypercholesterolemia(FH) and Low(&lt;10mg/dl), Intermediate (∼50mg/dl) or High(&gt;100mg/dl) Lp(a) levels on chronic LDL apheresis were evaluated. Twenty-five isopycnic density fractions(density &lt;1.015 to &gt;1.189 g/ml) were isolated from pre and post apheresis plasma(n=50 fractions per patient). OxPL and Lp-PLA2 mass and activity were quantitated with a variety of techniques under 3 conditions: in plasma, in each density fraction with direct plating techniques and on individual lipoproteins within each density fraction by using antibody capture assays to apoB-100(OxPL/apoB and Lp-PLA2/apoB), Lp(a)[OxPL/apo(a) and Lp-PLA2/apo(a)] and apoA-I(OxPL/apoA-I and Lp-PLA2/apoA-I)(total of 900 fractions per measure) and detecting OxPL and Lp-PLA2 with monoclonal antibodies E06 and 4B4, respectively. Results: In whole density gradients by direct plating techniques, OxPL were almost exclusively detected in the Lp(a) containing fractions(density 1.059-1.094 g/ml) and Lp-PLA2 mass and activity were present between the apoB and Lp(a) density fractions. In lipoprotein capture assays, OxPL/apoB and OxPL/apo(a) increased proportionally with increasing Lp(a) levels; Lp-PLA2/apoB and Lp-PLA2/apoA-I levels were highest in patients with Low Lp(a) but decreased proportionally with increasing Lp(a) levels; Lp-PLA2/apo(a) was lowest in patients with Low Lp(a) levels and increased proportionally with increasing Lp(a) levels. LDL apheresis significantly reduces levels of OxPL and Lp-PLA2 on apoB and Lp(a), particularly in patients with high Lp(a) levels Conclusions: This study documents that OxPL are primarily present on Lp(a) and Lp-PLA2 primarily on apoB, but the proportion of each increases on Lp(a) and decreases on apoB as plasma Lp(a) levels increase. These data suggest a pathophysiological relationship between Lp(a), OxPL and Lp-PLA2 and provide a rationale for understanding how they collectively mediate CVD in humans.

Relationship of IgG and IgM autoantibodies and immune complexes to oxidized LDL with markers of oxidation and inflammation and cardiovascular events: results from the EPIC-Norfolk Study

Levels of IgG and IgM autoantibodies (AA) to malondialdehyde (MDA)-LDL and apoB-immune complexes (ICs) were measured in 748 cases and 1,723 controls in the EPIC-Norfolk cohort and their association to coronary artery disease (CAD) events determined. We evaluated whether AA and IC modify CAD risk associated with secretory phospholipase A(2) (sPLA(2)) type IIA mass and activity, lipoprotein-associated PLA(2) activity, lipoprotein (a) [Lp(a)], oxidized phospholipids on apoB-100 (OxPL/apoB), myeloperoxidase, and high sensitivity C-reactive protein. IgG ICs were higher in cases versus controls (P = 0.02). Elevated levels of IgM AA and IC were inversely associated with Framingham Risk Score and number of metabolic syndrome criteria (p range 0.02-0.001). In regression analyses adjusted for age, smoking, diabetes, LDL-cholesterol, HDL-cholesterol, and systolic blood pressure, the highest tertiles of IgG and IgM AA and IC were not associated with higher risk of CAD events compared with the lowest tertiles. However, elevated levels of IgM IC reduced the risk of Lp(a) (P = 0.006) and elevated IgG MDA-LDL potentiated the risk of sPLA(2) mass (P = 0.018). This epidemiological cohort of initially healthy subjects shows that IgG and IgM AA and IC are not independent predictors of CAD events but may modify CAD risk associated with elevated levels of oxidative biomarkers.

Intravenous glutamine support downmodulats the release of plasma LPS and the activities of PLA2 and neutrophil elastase in taurocholate-induced acute severe pancreatitis in pigs

Objective To observe the effects of intravenous glutamine (Gln) support on plasma lipopolysaccharide (LPS,endotoxin) concentration and acitvities of phospholipase A2(PLA2) and neutrophil elastase (NE) in taurocholate-induced acute severe pancreatitis (ASP) in pigs. Methods Twenty-one pigs weighed 16 kg-22 kg were randomly divided into four groups: including sham-controlled group (sham group, n=5), ASP-controlled group(ASP group, n=5), ASP+glycine controlled group(Gly group, n=5) and ASP+Gln supported group (Gln group, n=6). Anesthesized pigs were subjected to ASP induced by injecting 1 ml/kg of mixed solution of 5% sodium taurocholate and 8 000～10 000 BAEE units trypsin/ml into pancreas via pancreatic duct, which was replaced by 0.9% sodium chloride phosphate buffer solution to be taken as sham group. Blood samples from caval vein was collected for the determinations of Gln, LPS, NE and PLA2. Plasma glutamine were measured by high performance liquid chromatography. Systemic plasma endotoxin levels was quantified by the chromogenic limulus amebocyte lysate (LAL) technique. All pigs were intravenously sacrificed by injecting 20 ml of 10%KCl. Anything involved in the processes of the sampling, preserving, measuring and so on had to be depyrogenated and to be asepsis. Results ASP porcine induced by sodium taurocholate mixed solution was associated with awfully lowed glutamine concentration but higher LPS, PLA2 and neutrophil elastase (NE) activities in plasma. There existed highly significant difference compared with the normal values (all P＜0.01 ). Intravenous glutamine support could effectively prevent the decrease of systemic plasma glutamine level (P＜0.01), and reduced the higher levels of systemic plasma LPS and the activities of plasma NE and PLA2 followed by acute severe pancreatitis induced by the mixed solusion of 5% sodium taurocholate and trypsin in pigs (all P＜0.01), but all were still higher than the normal values except for NE activities at 72 h after the induction of ASP.Conclusion It is suggested that maintaining higher plasma glutamine level could downregulate the level of plasma LPS and the activities of plasma PLA2 and NE, which is beneficial to lessen the cascade inflammatory responses irritated by these proinflammatory mediators and the functional lesions of extro-pancreas organs in pigs with ASP. Key words: Acute pancreatitis; Glutamine; Lipopolysaccharide; Neutrophil elastase; Phospholipase A2

Abstract 5474: Crucial Role of Nrf3 in Smooth Muscle Cell Differentiation From Stem Cells and Vessel Injury-Induced Neointima Formation

Nuclear factor erythroid 2-related factor 3 (Nrf3), a member of the cap’n’collar family of transcription factors that binds to the DNA-antioxidant responsive elements, have been reported to be involved in muscle precursor migration during early embryo development. The present study aimed to investigate the functional role of Nrf3 in stem cell differentiation into smooth muscle cells (SMCs). When embryonic stem cells were cultivated on collagen IV-coated plates, Nrf3 was up-regulated significantly following 1–6 days of cell differentiation. Knockdown of Nrf3 resulted in down-regulation of smooth muscle specific markers including smooth muscle actin, SM22, calponin and smooth muscle myosin heavy chain, while enforced expression of Nrf3 enhanced SMC differentiation in a dose-dependent manner. SMC-specific transcription factor myocardin, but not serum response factor, was significant upregulated by Nrf3 overexpression. Strikingly, the binding of serum response factor and myocardin to the promoter of smooth muscle differentiation genes was dramatic increased by Nrf3 overexpres-sion, and Nrf3 can direct bind to the smooth muscle gene promoters as demonstrated by chromatin immunoprecipitation (CHIP) assay. Moreover, NADPH-derived ROS production during SMC differentiation was further enhanced by Nrf3 overexpression through upregualtion of NADPH oxidase (NOX4) and inhibition of anti-oxidant signalling pathway. Furthermore, overexpression of Nrf3 resulted in increase of plasma phospholipase A2 (Pla2g7) production, while knockdown Nrf3 ablated the Pla2g7 gene expression and protein activity. Additionally, both Nrf3 and Pla2g7 were up-regulated in adult SMC phenotype swiching from proliferating to contractile phenotype upon serum starvation. Importantly, in vivo knockdown of Nrf3 in the vessel wall significant increased wire-injury-induced neointima formation in ApoE-deficient mice. Our findings demonstrated for the first time that Nrf3 has a crucial role in SMC differentiation from stem cells and important protective function in vessel injury-induced neointima formation, indicating that they could be potential new therapeutic targets for intervention of SMC proliferative-related vascular diseases.

Association between type II secretory phospholipase A2 plasma concentrations and activity and cardiovascular events in patients with coronary heart disease

Type II secretory phospholipase A(2) (sPLA(2)-IIA) is widely expressed in various cell types and may trigger local inflammatory responses. We sought to evaluate whether systemic sPLA(2) is associated with prognosis in patients with coronary heart disease (CHD). Plasma concentrations of sPLA(2) (ELISA) and sPLA(2) activity (selective fluorometric assay) were measured at baseline in a cohort of 1024 patients aged 30-70 years with CHD. The Cox-proportional hazards model was used to determine the prognostic value of sPLA(2) on a combined cardiovascular disease (CVD) endpoint after adjustment for covariates. During a mean follow-up of 4.1 years, 93 patients (9.1%) experienced a secondary CVD event. In a multivariable model, sPLA(2) mass and activity were associated with hazard ratios of secondary CVD events of 2.07 (95% CI, 1.17-3.66) and 1.65 (95% CI 0.96-2.84) for mass and activity, respectively, when extreme tertiles were compared. Further adjustment for cystatin C, N-terminal-probrain natriuretic peptide, C-reactive protein, and lipoprotein-associated phospholipase A(2) attenuated the associations, still showing a positive trend for mass but a less clear pattern for activity. However, when sPLA(2) mass and activity were analysed as continuous variables both still showed a statistically significant increase in risk in all models. Secretory phospholipase A(2) mass and activity appear to be predictive of secondary CVD events in patients with CHD.