Secretory Phospholipase A2 Activity Research Articles

Inhibiting arachidonic acid generation mitigates aging-induced hyperinsulinemia and insulin resistance in mice

BackgroundAging-related type 2 diabetes (T2DM) is characterized by hyperinsulinemia, insulin resistance, and β-cell dysfunction. However, the underlying molecular mechanisms remain to be unclear. MethodsWe conducted non-targeted metabolomics to compare human serum samples from young adults (YA), elderly adults (EA), and elderly adults with diabetes (EA+DM) of Chinese population. Adult mice and aged mice were intragastrically administered with varespladib every day for two weeks and metabolic characteristics were monitored. Serum levels of arachidonic acid, insulin, and C-peptide, as well as serum activity of secretory phospholipase A2 (sPLA2) were detected in mice. Mouse islet perfusion assays were used to assess insulin secretion ability. Phosphorylated AKT levels were measured to evaluate insulin sensitivities of peripheral tissues in mice. ResultsNon-targeted metabolomics analysis of human serum samples revealed differential metabolic signatures among the YA, EA, and EA+DM groups. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed significant enhancement of arachidonic acid metabolism and glycerophospholipid metabolism in the EA group compared with the YA group. Further analysis identified two metabolic fluxes that favored the accumulation of arachidonic acid in the elderly. Increased levels of arachidonic acid were also confirmed in aged mice with hyperinsulinemia and insulin resistance, together with subsequent glucose intolerance. Conversely, inhibiting the generation of arachidonic acid with varespladib, an inhibitor of sPLA2, reduced aging-associated diabetes by improving hyperinsulinemia and hepatic insulin resistance in aged mice but not in adult mice. Islet perfusion assays also showed that varespladib treatment suppressed the enhanced insulin secretion observed in aged islets. ConclusionsCollectively, our findings uncover that arachidonic acid serves as a metabolic hub in Chinese elderly population. Our results also suggest that arachidonic acid plays a fundamental role in regulating β-cell function during aging and point to a novel therapy for aging-associated diabetes.

Novel strategy: Identifying new markers for demyelination in diabetic distal symmetrical polyneuropathy

ObjectiveTo develop a novel strategy for identifying acquired demyelination in diabetic distal symmetrical polyneuropathy (DSP). BackgroundMotor nerve conduction velocity (CV) slowing in diabetic DSP exceeds expectations for pure axonal loss thus implicating superimposed acquired demyelination. MethodsAfter establishing demyelination confidence intervals by regression analysis of nerve conduction data from chronic inflammatory demyelinating polyneuropathy (CIDP), we prospectively studied CV slowing in 90 diabetic DSP patients with and without at least one motor nerve exhibiting CV slowing (groups A and B) into the demyelination range by American Academy of Neurology (AAN) criteria respectively and 95 amyotrophic lateral sclerosis (ALS) patients. Simultaneously, secretory phospholipase A2 (sPLA2) activity was assessed in both diabetic groups and 46 healthy controls. ResultsNo ALS patient exhibited CV slowing in more than two motor nerves based on AAN criteria or the confidence intervals. Group A demonstrated a significantly higher percentage of patients as compared to group B fulfilling the above criteria, with an additional criterion of at least one motor nerve exhibiting CV slowing in the demyelinating range and a corresponding F response in the demyelinating range by AAN criteria (70.3 % vs. 1.9 %; p < 0.0001). Urine sPLA2 activity was increased significantly in diabetic groups as compared to healthy controls (942.9 ± 978.0 vs. 591.6 ± 390.2 pmol/min/ml, p < 0.05), and in group A compared to Group B (1328.3 ± 1274.2 vs. 673.8 ± 576.9 pmol/min/ml, p < 0.01). More patients with elevated sPLA2 activity and more than 2 motor nerves with CV slowing in the AAN or the confidence intervals were identified in group A as compared to group B (35.1 % vs. 5.7 %, p < 0.001). Furthermore, 13.5 % of patients in diabetic DSP Group A, and no patients in diabetic DSP Group B, fulfilled an additional criterion of more than one motor nerve with CV slowing into the demyelinating range with its corresponding F response into the demyelinating range by AAN criteria. ConclusionA combination of regression analysis of electrodiagnostic data and a urine biological marker of systemic inflammation identifies a subgroup of diabetic DSP with superimposed acquired demyelination that may respond favorably to immunomodulatory therapy.

Novel Biomarker for Demyelination in Diabetic Distal Symmetric Polyneuropathy: A Prospective Study (P11-8.006)

<h3>Objective:</h3> To develop a new strategy to identify acquired demyelination in diabetic distal symmetric polyneuropathy (DSP). <h3>Background:</h3> Motor nerve conduction velocity (CV) slowing in diabetic DSP exceeds what is expected from pure axonal loss and can be attributed to additional acquired demyelination. <h3>Design/Methods:</h3> We prospectively studied CV and urine secretory phospholipase A2 (sPLA2) activity in 90 diabetic DSP patients divided into 2 groups A and B with and without at least one motor nerve with CV slowing in the demyelination range by AAN criteria. sPLA2 activity was tested in 46 healthy controls. In parallel, we studied CV in these diabetic patients using a regression analysis that we developed and validated from data from 114 CIDP patients. <h3>Results:</h3> Mean urine sPLA2 activity was significantly higher in diabetic groups compared to healthy controls, (942.9 ± 977.97 vs. 591.6 ± 390.15, pmol/min/ml p &lt; 0.05), and was significantly higher in group A compared to B, (1328.3 ± 1274.21 vs. 673.8 ± 576.93 pmol/min/ml, p = 0.0014). The number of patients with elevated sPLA2 activity and have more than 2 motor nerves with CV slowing in the AAN or regression analysis ranges was significantly higher in patients of group A compared to group B (35.1% vs. 5.7%, p = 0.0005). Furthermore, 13.5% in diabetic DSP group A and no patient in diabetic DSP group B fulfilled an additional criteria of more than one motor nerve with CV slowing in the demyelinating range with the corresponding F response in the demyelinating range by AAN criteria. <h3>Conclusions:</h3> To the best of our knowledge, the present study is the first to use a combination of regression analysis of electrodiagnostic data and a urine biological marker of inflammation to identify a subgroup of diabetic DSP with significant contribution of acquired demyelination and neuroinflammation in diabetic nerve injury. <b>Disclosure:</b> Mr. Jaffry has nothing to disclose. Miss Shaikh has nothing to disclose. Mr. Jaffry has nothing to disclose. Mr. Mandava has nothing to disclose. Mr. Trivedi has nothing to disclose. Mr. Ors has nothing to disclose. Ms. Faiz has nothing to disclose. Dr. Patel has nothing to disclose. Ankit Pahwa has nothing to disclose. Hongxin Chen has nothing to disclose. Timothy Cunningham has received intellectual property interests from a discovery or technology relating to health care. Dr. Sander has received personal compensation for serving as an employee of Grifols. Dr. Sander has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Grifols. Dr. Sander has received personal compensation in the range of $10,000-$49,999 for serving as an Expert Witness for Law firm. Dr. Souayah has received publishing royalties from a publication relating to health care.

Secretory phospholipase A2 expression and activity in preterm clinical chorioamnionitis with fetal involvement.

Secretory phospholipase A2 (sPLA2) regulates the first step of inflammatory cascade and is involved in several pathological processes. sPLA2 also plays a role in preterm labor and parturition, since they are triggered by inflammatory mediators such as prostaglandins. Interestingly, chorioamnionitis (i.e., the presence of intrauterine inflammation) is also often associated with preterm birth. We aimed to verify if chorioamnionitis with fetal involvement modifies sPLA2 activity and expression profile in mothers and neonates delivered prematurely. We collected maternal plasma and amniotic fluid, as well as bronchoalveolar lavage fluid from preterm neonates born to mothers with or without clinical chorioamnionitis with fetal involvement. We measured concentrations of sPLA2 subtype-IIA and -IB, total enzyme activity, and proteins. Urea ratio was used to obtain epithelial lining fluid concentrations. Enzyme activity measured in maternal plasma (P < 0.001) and amniotic fluid (P < 0.001) was higher in chorioamnionitis cases than in controls. This was mainly due to the increased production of sPLA2-IIA, as the subtype -IB was present in a smaller amount and was similar between the two groups; sPLA2-IIA was increased in epithelial lining fluid (P = 0.045) or increased, although without statistical significance, in maternal plasma (P = 0.06) and amniotic fluid (P = 0.08) of chorioamnionitis cases. Cytokines that are known to increase sPLA2-IIA expression (TNF-α and IL-1β) or whose expression was increased by sPLA2-IIA (IL-8) were higher in histologically confirmed chorioamnionitis [TNF-α (P = 0.028), IL-1β (P < 0.001), and IL-8 (P = 0.038)]. These data represent the basis for future studies on sPLA2-IIA inhibition to prevent deleterious consequences of chorioamnionitis and preterm birth.

Circulating Secretory Phospholipase A2 Activity following Snakebites and Its Relationship with Envenomation Status and Progression of Local Swelling.

We studied whether circulating secretory phospholipase A2 (sPLA2) activity reliably distinguished patients with snakebite envenomation from those with nonvenomous/dry snakebites, and whether patients with progressive local swelling had persistence of circulating sPLA2 activity despite antivenom treatment. We prospectively enrolled adults presenting to the emergency with a history of snakebite in the past 24 hours. We estimated circulating sPLA2 activity at baseline before antivenom administration and after 48 hours in those with envenomation. We enrolled 52 patients with snakebites (mean age 39.3 ± 12.6 years; 35 [67%] men), and 16 patients with infective cellulitis as controls. Thirty patients had local ± systemic envenomation; 15 were classified as dry/nonvenomous bites; and envenomation status was unclear in seven patients. Baseline sPLA2 activity was significantly higher in snakebite patients than that in those with infective cellulitis (4.64 [3.38-5.91] versus 3.38 [1.69-4.01] nmol/minute/mL; P = 0.005). Among patients with snakebites, sPLA2 activity in the highest quartile was significantly associated with envenomation (12 of 27 versus two of 22; P = 0.010). However, median sPLA2 activity did not differ significantly between patients with envenomation and the rest. Baseline sPLA2 activity was significantly associated with the maximum extent of limb swelling (P = 0.031 for trend). In envenomed patients, circulating sPLA2 activity significantly decreased after 48 hours compared with the baseline (5.49 [3.38-8.86] versus 3.38 [2.53-4.64]; P = 0.003) including those with progressive swelling. Although circulating sPLA2 activity was elevated following snakebites, its sensitivity to diagnose envenomation appears to be limited. Administration of more antivenom after systemic manifestations had reversed might not benefit patients with progressive local swelling.

Phospholipase A2 (PLA2) as an Early Indicator of Envenomation in Australian Elapid Snakebites (ASP-27).

Early diagnosis of snake envenomation is essential, especially neurotoxicity and myotoxicity. We investigated the diagnostic value of serum phospholipase (PLA2) in Australian snakebites. In total, 115 envenomated and 80 non-envenomated patients were recruited over 2 years, in which an early blood sample was available pre-antivenom. Serum samples were analyzed for secretory PLA2 activity using a Cayman sPLA2 assay kit (#765001 Cayman Chemical Company, Ann Arbor MI, USA). Venom concentrations were measured for snake identification using venom-specific enzyme immunoassay. The most common snakes were Pseudonaja spp. (33), Notechis scutatus (24), Pseudechis porphyriacus (19) and Tropidechis carinatus (17). There was a significant difference in median PLA2 activity between non-envenomated (9 nmol/min/mL; IQR: 7–11) and envenomated patients (19 nmol/min/mL; IQR: 10–66, p < 0.0001) but Pseudonaja spp. were not different to non-envenomated. There was a significant correlation between venom concentrations and PLA2 activity (r = 0.71; p < 0.0001). PLA2 activity was predictive for envenomation; area under the receiver-operating-characteristic curve (AUC-ROC), 0.79 (95% confidence intervals [95%CI]: 0.72–0.85), which improved with brown snakes excluded, AUC-ROC, 0.88 (95%CI: 0.82–0.94). A cut-point of 16 nmol/min/mL gives a sensitivity of 72% and specificity of 100% for Australian snakes, excluding Pseudonaja. PLA2 activity was a good early predictor of envenomation in most Australian elapid bites. A bedside PLA2 activity test has potential utility for early case identification but may not be useful for excluding envenomation.

Characterization of plasma secretory phospholipase A2 activity in the prairie rattlesnake (Crotalus viridis)

BackgroundPlasma phospholipase A2 (PLA2) enzyme activity is a key component of innate immunity in most vertebrates. We evaluated circulating secreted PLA2 activity of prairie rattlesnakes (Crotalus viridis) by incubation of plasma with bacteria labeled with fluorescent membrane lipids.ResultsIncubation of bacteria with increasing volumes of plasma resulted in volume-dependent lysis of fatty acids from bacterial membranes. The activity was rapid, with substantial activity recorded after only 5 min of incubation with labeled bacteria, and a linear response for 20 min. In addition, the lysis activity was temperature-dependent, increasing activities from 5 to 20 °C, peak activities at 25–30 °C, and then decreasing activities from 35 to 40 °C. Furthermore, the activity was inhibited in a concentration-dependent manner by p-bromophenacyl bromide, a specific inhibitor of PLA2 activity, which indicated that the observed activities were due to the presence of PLA2 in the plasma of C. viridis.ConclusionsThis study represents the first description of secretory PLA2 activity in the plasma of a snake. Our study shows that in addition to being an important component of snake venom, PLA2 enzymes play an important role in the snake’s immune response.

High-density lipoprotein functionality in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a heterogeneous disease which is characterized with excessive inflammation and autoantibodies, macrophage and complement activation, and subsequently immunologically mediated tissue damage. In spite of improved treatments of SLE, these patients experience premature atherosclerosis and the rate of mortality among them remains high. Autoantibodies and circulating immune complexes might contribute to the pathogenesis of atherosclerosis by injuring the endothelium, as well as inducing pro-inflammatory and pro-adhesive endothelial cell phenotypes, as well as altering the metabolism of lipoproteins involved in atherogenesis. Hence, high levels of atherogenic lipoproteins (like low-density lipoprotein (LDL) and very low-density lipoprotein (VLDL)) and low levels of high-density lipoprotein (HDL-C) are important risk factors for atherosclerotic cardiovascular complications in SLE patients but these traditional risk factors fail to fully explain the increased risk of cardiovascular disease (CVD) in these patients. The exact mechanism by which inflammation decreases HDL levels is not defined, but decreases in apoA-I production and lecithin cholesterol acyltransferase (LCAT) activity, as well as increased serum amyloid A (SAA), endothelial lipase and secretory phospholipase A2 activity (PLA2) could all contribute. In addition, during inflammation multiple changes in HDL structure occur, leading to alterations in HDL function which may be implicated in the CVD complications of SLE. Therefore, this review will aim to identify the mechanisms implicated in HDL dysfunction which occurs in SLE patients.

Effect of cooling on lung secretory phospholipase A2 activity in vitro, ex vivo, and in vivo.

Hypothermia can modify surfactant composition and function. Secretory phospholipase A2 (sPLA2) hydrolyses surfactant phospholipids and is important in the pathobiology of several critical respiratory disorders. We hypothesize that sPLA2 activity might be influenced by the temperature partially explaining surfactant changes. This study aims to evaluate comprehensively the effect of hypothermia on sPLA2 activity. We measured sPLA2 activity at different temperatures, alone or combined with bile acids, in vitro (incubating human recombinant sPLA2-IIA and porcine sPLA2-IB), ex vivo (by cooling bronchoalveolar lavage samples from neonates with respiratory distress syndrome or no lung disease), and in vivo (using lavage samples obtained before and after 72 h of whole body cooling in neonates with hypoxic-ischemic encephalopathy). We also measured concentrations of various sPLA2 subtypes and natural sPLA2 inhibitors in in vivo cooled samples. Results were corrected for protein content and dilution. In vitro cooling did not show any effect of hypothermia on sPLA2. Ex vivo cooling did not alter total sPLA2 activity, and the addition of bile acids increased sPLA2 activity irrespective of the temperature and the type of sampled patient. In vivo hypothermia reduced median sPLA2 activity from 16.6 [15.2-106.7] IU/mg to 3.3 [2.7-8.5] IU/mg ( P = 0.026) and mean sPLA2-IIA from 1.1 (0.8) pg/μg to 0.6 (0.4) pg/μg ( P = 0.047), whereas dioleylphosphatidylglycerol increased from 8.3 (3.9)% to 12.8 (5.1)% ( P = 0.02). Whole body hypothermia decreases in vivo global sPLA2 activity in bronchoalveolar lavage fluids through the reduction of sPLA2-IIA and increment of dioleylphosphatidylglycerol. This effect is absent during in vitro or ex vivo hypothermia.

Modulation of the enzyme activity of secretory phospholipase A2, lipoxygenase and cyclooxygenase involved in inflammation and disease by extracts from some medicinal plants used for skincare and beauty

Proliferation of acute inflammation under pathological conditions makes targeting the pro-inflammatory enzymes a therapeutic intervention. The inflammation process contributes significantly to the appearance of the skin as a result of scarring and dark spots that develop. Inflammation is a normal physiological process employed to remove tissue damage due to the barrier breach of the skin. This study aimed to evaluate the inhibition and induction of enzymes associated with skin inflammation by 10 medicinal plants used traditionally for skincare and beauty in South Africa. Plants were initially examined for their total phenolic and flavonoid contents. Acetone and water extracts of the selected plants were assayed for their inhibitory activities of secretory phospholipase A2 (sPLA2), lipoxygenase (15-LOX) and cyclooxygenase (COX) enzymes using an inhibitor screening assay kit (Cayman Chemical, Ann Arbor, MI). The total phenolic content and flavonoid content were significantly high for Cassipourea flanaganii (Schinz) Alston. Extracts of Aloe ferox Mill and Plantago lanceolata L yielded a high content of total phenols and flavonoids, respectively. Water and acetone extracts of C. flanaganii and Chenopodium album L exhibited notable inhibitory activity against sPLA2 with IC50 values of 12.34 and 10.75 μg/mL, respectively. Water and acetone extracts of C. flanaganii exhibited moderate inhibitory activity of 15-LOX enzyme with IC50 values of 16.72 and 21.59 μg/mL, respectively. Water extracts of C. album also inhibited the activity of 15-LOX enzyme with an IC50 value of 18.99 μg/mL. Water extracts of Haemanthus albiflos Jacq, Ruta graveolens L, A. ferox, C. flanaganii and Clausena anisata (Willd.) Hook.f. ex Benth had a significantly high inhibitory activity against COX-2 enzyme with IC50 values ranging from 4.23 to 6.89 μg/mL. Furthermore, acetone extracts of Rorippa nasturtium-aquaticum (L.) Hayek, P. lanceolata and A. ferox significantly inhibited the activity of COX-2 with IC50 values ranging from 2.69 to 4.36 μg/mL. The observed selective inhibition of COX-2 enzyme by extracts of C. flanaganii, P. lanceolata and R. nasturtium-aquaticum is significant when screening for natural inhibitors with less risk of gastro-intestinal health effects. The selective inhibition of COX-2 enzyme is beneficial in modulation of skin inflammation during pathological conditions. Therefore, extracts from these plants can be incorporated in beauty formulations intended for treatment of chronic inflammation of the skin.

Integrated Human Evaluation of the Lysophosphatidic Acid Pathway as a Novel Therapeutic Target in Atherosclerosis

Variants in the PLPP3 gene encoding for lipid phosphate phosphohydrolase 3 have been associated with susceptibility to atherosclerosis independently of classical risk factors. PLPP3 inactivates lysophosphatidic acid (LPA), a pro-inflammatory, pro-thrombotic product of phospholipase activity. Here we performed the first exploratory analysis of PLPP3, LPA, and LPA receptors (LPARs 1–6) in human atherosclerosis. PLPP3 transcript and protein were repressed when comparing plaques versus normal arteries and plaques from symptomatic versus asymptomatic patients, and they were negatively associated with risk of adverse cardiovascular events. PLPP3 localized to macrophages, smooth muscle, and endothelial cells (ECs) in plaques. LPAR 2, 5, and especially 6 showed increased expression in plaques, with LPAR6 localized in ECs and positively correlated to PLPP3. Utilizing in situ mass spectrometry imaging, LPA and its precursors were found in the plaque fibrous cap, co-localizing with PLPP3 and LPAR6. In vitro, PLPP3 silencing in ECs under LPA stimulation resulted in increased expression of adhesion molecules and cytokines. LPAR6 silencing inhibited LPA-induced cell activation, but not when PLPP3 was silenced simultaneously. Our results show that repression of PLPP3 plays a key role in atherosclerosis by promoting EC activation. Altogether, the PLPP3 pathway represents a suitable target for investigations into novel therapeutic approaches to ameliorate atherosclerosis.

AKTIVITAS FOSFOLIPASE-A2 SEKRETORIS PLASMA TROMBOSITOPENIA DEMAM BERDARAH DENGUE

Infected macrophages by dengue virus will produce phospholipase-A2 (PLA2) enzyme, that can promote arachidonic acidmetabolism that produce inflammatory mediators, causing endhothelial damage and severe plasma leakage. Capillary endothelialdamage can cause platelet adhesion and aggregation, so that many platelets will be consumed. The role of sPLA2 (secretoryphospholipase-A2), which is a part of PLA2 in dengue and thrombocytopenia up to now has not been widely studied. The objective ofthe study is to analyze the association between the activity of plasma secretory phospholipase-A2 and the degree of thrombocytopeniain DHF adult patients. the study is carried out by a cross sectional, observational analytical study on 45 hospitalized adult patientssuffering dengue hemorrhagic fever in the Tropical Infection Ward, Department of Internal Medicine, Dr. Soetomo Hospital Surabaya,which has been conducted from February–December 2009. The diagnosis of Dengue Haemorrhagic Fever (DHF) was based on the1997 World Health Organization (WHO) criteria, that minimally had one positive serology marker of dengue. Venous blood wastaken from the patient for examining the activity of secretory phospholipase-A2 by correlated enzyme assay method, and plateletcount using automated hematology analyzer. The results of the secretory phospholipase-A2 activity and degree of thrombocytopeniawere analyzed by Pearson correlation test to determine the correlation between the two variables. In this study so far was foundthat the secretory phospholipase-A2 activity in DHF patients was 36.9–195.6 unit/mL (mean 97.49 unit/mL, SD 30.06 unit/mL).The mean of secretory phospholipase-A2 activity was increased according to the degree of thrombocytopenia severity. The mean ofsecretory phospholipase-A2 activities were 91.65 unit/mL, 98.94 unit/mL, and 110.47 unit/mL. The degree of thrombocytopeniawas divided into mild, moderate, and severe. Most of the patients showed mild thrombocytopenia. The sPLA2 activity in this studywas increased in DHF patients with second day of fever, and then decreased at the third and forth day of fever, and increased inDBD patients suffering fifth day of fever. The statistical analyzes show a non significant correlation between secretory phospholipaseA2 activity and degree of thrombocytopenia (p = 0.579). This result may be caused by several factors which influencing thethrombocytopenia in DHF, such as bone marrow suppression, dengue viral serotype, influence of cytosolic phospholipase-A2 (cPLA2)activity, and other proinflammatory cytokines which in this study could not be controlled. Statistical analyzes show a significantcorrelation between sPLA2 activity and the day of fever (p = 0.04). Further studies should have to be carried out in order to knowthe pattern of sPLA2 activity in DHF grade I, II, III, and IV, and to know the influence of other proinflammatory cytokines and viralserotypes in sPLA2 activities.

Non-Clinical Studies for Evaluation of 8-C-Rhamnosyl Apigenin Purified from Peperomia obtusifolia against Acute Edema.

Compound 8-C-rhamnosyl apigenin (8CR) induced a moderate reduction in the enzymatic activity of secretory phospholipase A2 (sPLA2) from Crotalus durissus terrificus and cytosolic phospholipase A2 (cPLA2), but the compound also significantly inhibited the enzymatic activity of the enzyme cyclooxygenase. In vitro assays showed that the compound induced a slight change in the secondary structure of sPLA2 from Crotalus durissus terrificus snake venom. In vivo assays were divided into two steps. In the first step, the 8CR compound was administered by intraperitoneal injections 30 min prior to administration of sPLA2. In this condition, 8CR inhibited edema and myonecrosis induced by the sPLA2 activity of Crotalus durissus terrificus in a dose-dependent manner by decreasing interleukin-1β (IL-1β), tumor necrosis factor α (TNF-α), prostaglandin E2 (PGE2), and lipid peroxidation. This has been demonstrated by monitoring the levels of malondialdehyde (MDA) in rat paws after the course of edema induced by sPLA2. These results, for the first time, show that sPLA2 of Crotalus durissus terrificus venom induces massive muscle damage, as well as significant edema by mobilization of cyclooxygenase enzymes. Additionally, its pharmacological activity involves increased lipid peroxidation as well as TNF-α and IL-1β production. Previous administration by the peritoneal route has shown that dose-dependent 8CR significantly decreases the enzymatic activity of cyclooxygenase enzymes. This resulted in a decrease of the amount of bioactive lipids involved in inflammation; it also promoted a significant cellular protection against lipid peroxidation. In vivo experiments performed with 8CR at a concentration adjusted to 200 μg (8 mg/kg) of intraperitoneal injection 15 min after sPLA2 injection significantly reduced sPLA2 edema and the myotoxic effect induced by sPLA2 through the decrease in the enzymatic activity of cPLA2, cyclooxygenase, and a massive reduction of lipid peroxidation. These results clearly show that 8CR is a potent anti-inflammatory that inhibits cyclooxygenase-2 (COX-2), and it may modulate the enzymatic activity of sPLA2 and cPLA2. In addition, it was shown that Crotalus durissus terrificus sPLA2 increases cell oxidative stress during edema and myonecrosis, and the antioxidant properties of the polyphenolic compound may be significant in mitigating the pharmacological effect induced by sPLA2 and other snake venom toxins.

Carriers of the PCSK9 R46L Variant Are Characterized by an Antiatherogenic Lipoprotein Profile Assessed by Nuclear Magnetic Resonance Spectroscopy-Brief Report.

Carriers of the PCSK9 (proprotein convertase subtilisin/kexin 9) R46L genetic variant (rs11591147) are characterized by low levels of low-density lipoprotein cholesterol and a decreased risk of cardiovascular disease. We studied the impact of the R46L variant on lipoprotein size and composition. Lipoprotein size and composition were measured by nuclear magnetic resonance spectroscopy in 2373 participants of the EPIC (European Prospective Investigation into Cancer and Nutrition)-Norfolk study. After adjusting for age, sex, and cardiovascular disease status, carriers of the R46L variant (n=77) were characterized by lower concentrations of very low-density lipoprotein particles (85.8±26.2 versus 99.0±33.3 nmol/L; P<0.001), low-density lipoprotein particles (1479.7±396.8 versus 1662.9±458.3 nmol/L; P<0.001), and lipoprotein(a) (11.1 [7.2-28.6] versus 12.4 [6.7-29.1] mg/dL; P<0.001) compared with noncarriers. Total high-density lipoprotein particle and very low-density lipoprotein, low-density lipoprotein, and high-density lipoprotein particle sizes were comparable in carriers and noncarriers. Carriers were characterized by lower secretory phospholipase A2 (4.2±0.9 versus 4.6±1.3 nmol/mL/min; P=0.004) and lipoprotein-associated phospholipase A2 activity (47.5±14.1 versus 52.4±16.2 nmol/mL/min; P=0.02) compared with noncarriers. Results of this study suggest that carriers of the PCSK9 R46L genetic variant have lower very low-density lipoprotein and low-density lipoprotein particle concentrations, lower lipoprotein(a) levels, and lower secretory phospholipase A2 and lipoprotein-associated phospholipase A2 activity compared with noncarriers.

Anti-inflammatory and antioxidative effects of six pentacyclic triterpenes isolated from the Mexican copal resin of Bursera copallifera.

Background Bursera copallifera (Burseraceae) releases a resin known as “copal ancho” which has been used, since pre-Colombian times, as ceremonially burned incense and to treat tooth ache, tumors, arthritis, cold, cough, and various inflammatory conditions; however, its anti-inflammatory potential is poorly studied. The aim of the present study was to isolate, quantify, and to investigate the anti-inflammatory activity of triterpene compounds isolated from the copal resin of B. copallifera.MethodsThe constituents present in the total resin of B. copallifera were obtained by successive chromatographic procedures, and quantitative analysis was performed by High Performance Liquid Chromatography (HPLC). Anti-inflammatory effects of the isolated triterpenes were investigated to determine their inhibitory effects on phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced edema in mice, viability and nitric oxide (NO) production inhibition on lipopolysaccharide (LPS)-activated RAW 264.7 macrophages, and inhibition of cyclooxygenase (COX)-1, COX-2 and secretory Phospholipase A2 (sPLA2) activities in vitro.ResultsQuantitative phytochemical analysis of the copal resin showed the presence of six pentacyclic triterpenes of which, 3-epilupeol (59.75 % yield) and α-amyrin (21.1 % yield) are the most abundant. Among the isolated triterpenes, 3-epilupeol formiate (Inhibitory Concentration 50 % (IC50) = 0.96 μmol), α.amyrin acetate (IC50 = 1.17 μmol), lupenone (IC50 = 1.05 μmol), and 3-epilupeol (IC50 = 0.83 μmol) showed marked inhibition of the edema induced by TPA in mice. α-amyrin acetate and 3-epilupeol acetate, at 70 μM, also inhibited the activity of COX-2 by 62.85 and 73.28 % respectively, while α-amyrin and 3-epilupeol were the best inhibitors of the production of NO in LPS-activated RAW 264.7 cells with IC50 values of 15.5 and 8.98 μM respectively, and did not affected its viability. All compounds moderately inhibited the activity of PLA2.ConclusionsThis work supports the folk use of B. copallifera and provides the basis for future investigations about the therapeutic use of this resin in treating inflammation.

Effect of inflammation on HDL structure and function.

Studies have shown that chronic inflammatory disorders, such as rheumatoid arthritis, systemic lupus erythematosus, and psoriasis are associated with an increased risk of atherosclerotic cardiovascular disease. The mechanism by which inflammation increases cardiovascular disease is likely multifactorial but changes in HDL structure and function that occur during inflammation could play a role. HDL levels decrease with inflammation and there are marked changes in HDL-associated proteins. Serum amyloid A markedly increases whereas apolipoprotein A-I, lecithin:cholesterol acyltransferase, cholesterol ester transfer protein, paraoxonase 1, and apolipoprotein M decrease. The exact mechanism by which inflammation decreases HDL levels is not defined but decreases in apolipoprotein A-I production, increases in serum amyloid A, increases in endothelial lipase and secretory phospholipase A2 activity, and decreases in lecithin:cholesterol acyltransferase activity could all contribute. The changes in HDL induced by inflammation reduce the ability of HDL to participate in reverse cholesterol transport and protect LDL from oxidation. During inflammation multiple changes in HDL structure occur leading to alterations in HDL function. In the short term, these changes may be beneficial resulting in an increase in cholesterol in peripheral cells to improve host defense and repair but over the long term these changes may increase the risk of atherosclerosis.

Correlation of secretory phospholipase-A2 activity and fatty acids in cerebrospinal fluid with liver enzymes tests

Introduction: The aim was to determine whether secretory phospholipase-A2 (sPLA2) activity and fatty acids in cerebrospinal fluid (CSF) are correlated with liver enzymes tests. Methods: CSF and serum samples were collected from 49 patients (age 18-65) as part of routine diagnostic testing. Along with serum liver enzymes aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP), the fatty acid composition of CSF was measured by gas liquid chromatography. CSF enzyme activities of sPLA2 were measured using the standard assay with diheptanoyl thio-phosphatidylcholin as substrate. Results: The saturated fatty acids (SFAs) including palmitic acid and stearic acid were positively, and the unsaturated fatty acids including oleic acid and linoleic acid were negatively correlated with liver enzymes tests. In regression analysis with adjustment for body mass index (BMI), the elevated liver enzymes tests were positively associated with activity of sPLA2 (β > 0.31, P 0.38, P < 0.010) and negatively with total monounsaturated fatty acids (MUFAs) (β < -0.40, P < 0.001) contents of CSF. Conclusion: CSF activity of sPLA2 and fatty acids may be linked to peripheral markers of liver function, suggesting an indirect impact of central fatty acids on hepatocytes function and metabolism.

Effect of prenatal steroidal inhibition of sPLA2 in a rat model of preterm lung

IntroductionSecretory phospholipase A2 regulates surfactant catabolism and inflammatory cascade. This enzyme is correlated with compliance, oxygenation and major outcomes in various forms of acute respiratory failure. Steroids inhibit secretory phospholipase A2 in cell culture and are widely used to boost surfactant production before preterm delivery. No data are available about the effect of antenatal steroids on secretory phospholipase A2 in the offspring: we aimed to study this effect in a rat model of preterm lung. Material and methodsFifteen pregnant Wistar rats were randomized to receive betamethasone, dexamethasone or placebo at 20 and 21 days gestation. Newborn rats were supported for 8 h and then sacrificed: lung tissue was analysed for secretory phospholipase A2 expression and activity, inflammatory mediators and protein content. Lipidomics was analysed using liquid chromatography-mass spectrometry. ResultsSecretory phospholipase A2 expression was significantly reduced by antenatal steroids (p < 0.001). Secretory phospholipase A2 activity, TNFα and lysophosphatidylethanolamine, a product of phospholipase reaction, were lowest in betamethasone-treated rats (p < 0.001). There was a strong correlation between secretory phospholipase A2 activity and lysophosphatidylethanolamine (r = 0.75; p = 0.001) and this remained significant after adjustment for total proteins or phospholipids. ConclusionsAntenatal steroids decrease secretory phospholipase A2 in rat model of preterm lung.

Sphingomyelin Regulates the Activity of Secretory Phospholipase A2 in the Plasma Membrane.

We examined the effect of the cellular sphingolipid level on the release of arachidonic acid (AA) and the activity of secretory phospholipase A2 (sPLA2 ) using two Chinese hamster ovary (CHO)-K1 cell mutants, LY-B and LY-A cells, deficient in sphingolipid synthesis. In LY-B cells, deficiency of sphingolipids enhanced the release of AA induced by bee venom sPLA2-III or human sPLA2-V. These alterations were reversed by replenishment of exogenous sphingomyelin (SM). In LY-A cells, deficiency of SM increased the release of AA induced by sPLA2. In CHO-K1 cells, decrease and increase of SM level in the plasma membrane by pharmacological methods increased and inhibited the release of AA, respectively. SM inhibited the activity of sPLA2 in vitro. Niemann-Pick disease type C (NPC) is a lysosomal storage disorder caused by mutation of either the NPC1 or NPC2 gene, and is characterized by accumulation of cholesterol and sphingolipids including SM in late endosomes/lysosomes. Increased levels of AA and sPLA2 activity are involved in various neurodegenerative diseases. In CHO cells lacking NPC1 (A101 cells), SM level was lower in the plasma membrane, while it was higher in late endosomes/lysosomes. The release of AA induced by sPLA2 was increased in A101 cells than that in parental cells (JP17 cells), which was attenuated by adding exogenous SM. In addition, sPLA2 -III-induced cytotoxicity in A101 cells was much higher than that in JP17 cells. These results suggest that SM in the plasma membrane plays important roles in regulating sPLA2 activity and the enzyme-induced cytotoxicity in A101 cells.

Abstract 11566: Beyond LDL Cholesterol: Carriers of the PCSK9 R46L Variant Are Characterized by an Anti-Atherogenic Lipoprotein Profile Assessed by Nuclear Magnetic Resonance Spectroscopy

Background: Carriers of the PCSK9 R46L genetic variant are characterized by low levels of low-density lipoprotein (LDL) cholesterol and a decreased risk of cardiovascular disease (CVD). Whether these individuals are characterized by other features of a more beneficial lipoprotein-lipid profile is unknown. Methods and Results: We measured the lipoprotein-lipid profile of 2373 participants of the European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk study by nuclear magnetic resonance spectroscopy. Among them, 77 participants carried at least one allele of the R46L genetic variant. Carriers and non-carriers had comparable clinical characteristics (age, body mass index, blood pressure, smoking and diabetes prevalence). As expected, carriers had lower LDL cholesterol levels compared to non-carriers (3,75±0,99 vs. 4,16±1,01 mmol/L, p&lt;0.001 in carriers vs. non-carriers, respectively). Carriers were characterized by a lower very low-density lipoprotein (VLDL) particle concentration and a lower LDL particle concentration of any size (Table). Total high-density lipoprotein (HDL) particle concentration was not different in carriers vs. non-carriers. However, carriers had a higher concentration of large HDL particles and a higher mean HDL particle size. We also found that carriers were characterized by a lower secretory phospholipase A2 (sPLA2) activity (4,21±0,88 vs. 4,61±1,26, nmol/ml/min p=0.004 in carriers vs. non-carriers, respectively) and a lower lipoprotein-associated phospholipase A2 (Lp-PLA2) activity (47,5±14,1 vs. 52,4±16,2 nmol/ml/min, p=0.008 in carriers vs. non-carriers, respectively). Conclusions: Results of this study suggest that on top of having low LDL cholesterol levels, carriers of the PCSK9 R46L genetic variant have a lower VLDL and LDL particle concentration, a higher concentration of large HDL particles and lower sPLA2 and Lp-PLA2 activity. This anti-atherogenic profile may explain to a certain extent the reduced CVD risk observed in carriers of the PCSK9 R46L genetic variant.