Search results for "PHOSPHOLIPASE A(2)"
showing 10 items of 70 documents
Therapeutic modulation of lipoprotein-associated phospholipase A2 (Lp-PLA2)
2011
Lipoprotein-associated phospholipase A2 (Lp-PLA2) is a calcium-independent phospholipase A2 that circulates in plasma in association with lipoprotein particles, whereas in atherosclerotic plaques it is co-localized with macrophages. Lp-PLA2 generates two proinflammatory mediators, lysophosphatidylcholine and oxidized nonesterified fatty acids, which play a role in the development of atherosclerotic lesions and formation of a necrotic core, leading to more vulnerable plaques. Epidemiologic studies demonstrate that increased circulating levels of Lp-PLA2 predict an increased risk of myocardial infarction, stroke and cardiovascular mortality. Furthermore, histologic examination of diseased hum…
Lipoprotein-associated phospholipase A2 activity is increased in patients with definite familial hypercholesterolemia compared with other forms of hy…
2018
Background and Aim: Lipoprotein-associated phospholipase A2(Lp-PLA2) plays a key role in atherosclerosis development. It is considered a marker of increased risk of cardiovascular disease (CVD) and plaque vulnerability. Familial hypercholesterolemia (FH) is a genetic disorder characterized by elevated plasma levels of low-density lipoprotein cholesterol and a higher prevalence of early CVD. Our aim was to evaluate the differences in Lp-PLA2activity in a population of hypercholesterolemic patients with and without definite FH. Methods and Results: Hypercholesterolemic patients were consecutively recruited. Definite FH was defined according to Dutch Lipid Clinic Network criteria â¥8. All pat…
Selective killing of human monocytes and cytokine release provoked by sphingomyelinase (beta-toxin) of Staphylococcus aureus.
1996
The best-known activity of Staphylococcus aureus sphingomyelinase C, alias beta-toxin, is as a hemolysin that provokes hot-cold lysis of erythrocytes which contain substantial amounts of sphingomyelin in the plasma membrane. Sheep erythrocytes are most susceptible, and we found that one hemolytic unit, representing the toxin concentration that elicits 50% hemolysis of 2.5 X 10(8) erythrocytes per ml, corresponds to 0.05 enzyme units or to approximately 0.25 microg of sphingomyelinase per ml. The cytotoxic action of beta-toxin on nucleated cells has not been described in any detail before, and the present investigation was undertaken to fill this information gap. We now identify beta-toxin a…
Two fungal lanostane derivatives as phospholipase A2 inhibitors.
1996
The hydroalcoholic extract of Poria cocos and two lanostane derivatives isolated from it, pachymic acid (1) and dehydrotumulosic acid (2), were active as inhibitors of phospholipase A2 from snake venom when a polarographic method was used. Dehydrotumulosic acid exhibited an IC50 of 0.845 mM. These two compounds are structurally related to certain triterpenoids from Ganoderma and Schinus that have previously been described as competitive inhibitors of phospholipase A2. These comprise a new group of natural potential antiinflammatory agents due to their interaction with that enzyme.
Role of three isoforms of phospholipase A2in capacitative calcium influx in human T-cells
2002
The present study was conducted on human Jurkat T-cell lines in order to elucidate the role of phospholipase A2 in capacitative calcium entry. We have employed thapsigargin (TG) that induces increases in [Ca2+]i by emptying the calcium pool of endoplasmic reticulum, followed by capacitative calcium entry. We designed a Ca2+ free/Ca2+ reintroduction (CFCR) protocol for the experiments, conducted in Ca2+-free medium. By employing CFCR protocol, we observed that addition of exogenous arachidonic acid (AA) stimulated TG-induced capacitative calcium influx. The liberation of endogenous AA and its autocrine action seems to be implicated during TG-induced capacitative calcium influx: TG potentiate…
Anti-inflammatory profile of dehydrocostic acid, a novel sesquiterpene acid with a pharmacophoric conjugated diene
2005
Sesquiterpene acids are natural products that, in contrast with the thoroughly studied sesquiterpene lactones, have received little pharmacological attention. A good source of this class of compounds is Inula viscosa (Asteraceae), a plant with documented anti-inflammatory effects. The present paper gives the results of our investigations on the biochemical mechanisms involved in the anti-inflammatory activity of one such compound, dehydrocostic acid. The most salient findings were that in vitro dehydrocostic acid inhibits leukotriene B(4) production (IC(50)=22 microM), elastase activity (IC(50)=43 microM) and bee venom phospholipase A(2) activity (IC(50)=17 microM). Furthermore, this sesqui…
A029 Identification of polymorphisms in the gene encoding secreted phospholipase A2 group X and study of their role in coronary artery disease. The a…
2009
Human secreted phospholipases A2 (sPLA2s) represent novel attractive therapeutic targets and biomarkers in coronary artery diseases (CAD). We have shown that human Group X sPLA2 (hGX sPLA2) is present in atherosclerotic lesions and that hGX sPLA2 modified LDL induces foam cell formation. To elucidate whether hGX sPLA2 has a causative role in CAD we have screened the human PLA2G10 gene to identify frequent polymorphisms, and we have examined their possible association with cardiovascular end-points and intermediate inflammatory phenotypes in a large prospective study of patients with CAD (the AtheroGene study). Although no significant association was found between the various polymorphisms i…
Natural Triterpenoids as Anti-Inflammatory Agents
2000
Abstract This chapter reviews the natural triterpenes with anti-inflammatory activity, including the traditional ones and the new compounds isolated over the last six years. Triterpenes are widely distributed in plants, and in many cases are the principles responsible for their anti-inflammatory effects. Many of these compounds are active in different in vivo experimental models such as hind paw edema induced by carrageenan, serotonin and phospholipase A2; ear edema induced by phorbol and daphnane esters, ethylphenylpropiolate, arachidonic acid and capsaicin; adjuvant arthritis and experimental models of allergy. Other effects have been studied in vitro, and some triterpenes are active agai…
Effects of free fatty acids, lysophosphatides and phospholipase treatment on lipid peroxidation of myocardial homogenates and membrane fractions
1987
The effects of various free fatty acids, lysophosphatides and phospholipase treatments on the enzymatic and the non-enzymatic lipid peroxidation capacities in the heart homogenates and subcellular fractions were studied. The results showed a dose related inhibition of both the enzymatic and non-enzymatic lipid peroxidation with free fatty acids. A significant inhibition occurred as early as at the concentration of 25–50 μM of several fatty acids both in homogenates and in organelle fractions. In general, the inhibition was greatest with cis-unsaturated, long-chain fatty acids. The inhibition was also induced by the pretreatment of the homogenates with phospholipase A2 but not with phospholi…
ChemInform Abstract: Dysidotronic Acid, a New and Selective Human Phospholipase A2 Inhibitor from the Sponge Dysidea sp.
2010
Abstract A new bioactive sesquiterpenoid, named dysidotronic acid 1, with a rearranged drimane skeleton has been isolated from the sponge Dysidea sp. from Vanuatu islands, along with bolinaquinone 2. The chemical structure of 1 was determined on the basis of spectroscopic data. Dysidotronic acid significantly inhibited human synovial phospholipase A2 (PLA2) at 10 μM, with an IC50 value of 2.6 μM and a higher selectivity and potency towards this enzyme than the reference inhibitor manoalide.