Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0004153 (atherosclerosis)
 77,401 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Prostacyclin (PGI(2)) is a potent vasodilator and inhibitor of platelet aggregation that is produced by prostacyclin synthase via the cyclooxygenase (COX) pathway of arachidonic acid metabolism. We investigated the potential role of COX-2 in the production of vasoactive prostanoids by aortic tissue in a rabbit model of dietary cholesterol-induced atherosclerosis. COX-1 was detected as the major isoform by immunoblot analysis in extracts from aortas of normal and 8 week cholesterol-fed animals with COX-2 being induced in atherosclerotic plaques from cholesterol-fed animals. Aortic tissue from cholesterol-fed animals showed decreased levels of basal 6-keto-PGF(1 alpha) and PGE(2) production as compared to the normal controls but showed no difference with respect to their ability to synthesize these prostanoids in response to exogenous arachidonic acid. The highly selective COX-2 inhibitors rofecoxib and the furanone DFP at concentrations of up to 10 micromol/l had no effect on the arachidonic acid-dependent production of 6-keto-PGF(1 alpha), in contrast to indomethacin, which caused a complete inhibition at 0.5 micromol/l. Celecoxib caused a significant inhibition of 6-keto-PGF(1 alpha) at 10 micromol/l but had little effect when the dose was lowered to 1 micromol/l. Similar effects of these inhibitors were observed with respect to the production of PGE(2) and no major difference was observed between aortic tissues from normal and cholesterol-fed animals with regard to inhibitor sensitivity. These results indicate that in a rabbit model of early stage cardiovascular disease, the basal production of 6-keto-PGF(1 alpha) and PGE(2) by aortic tissue is decreased. Furthermore, COX-2 expression is induced in atherosclerotic plaques and may play a role in altering localized synthesis of prostanoids in these lesions but does not appear to significantly impact the arachidonic acid-dependent prostacylin production of aortic tissues, which is largely mediated by COX-1.
Atherosclerosis 2001 Aug
PMID:Effects of COX-2 inhibitors on aortic prostacyclin production in cholesterol-fed rabbits. 1147 39

Macrophage infiltration, inflammatory processes and oxidatively modified low density lipoprotein (LDL) are known contributing factors in the formation of the atherosclerotic plaque. To determine whether a direct link might exist between these factors, we examined the effect of oxidized LDL upon proinflammatory cytokine production in adherent human peripheral blood mononuclear leukocytes. Oxidized LDL, as well as a combination of cholesterol and 25-hydroxycholesterol, induced tumor necrosis factor-alpha (TNFalpha) and interleukin-1 beta (IL-1 beta) mRNA as measured by quantitative real time PCR, by a maximum of two- to fourfold following a 24-h incubation. Analysis of cell culture supernatants revealed a concomitant stimulation of TNFalpha and IL-1 beta secreted protein as determined by ELISA. Treatment of human peripheral blood mononuclear leukocytes with oxidized LDL or the combination of cholesterol and 25-hydroxycholesterol caused activation of p38 alpha as determined by the ability of immunoprecipitated p38 to phosphorylate an ATF-2 fusion protein, a surrogate substrate of p38 alpha. VK-19911 (Pyridine, 4-[4-(4-fluorophenyl)-1-(4-piperidinyl)-1H-imidazol-5-yl]-dihydrochloride), a specific inhibitor of p38 alpha, prevented the induction of TNFalpha and IL-1 beta by oxidized LDL in a dose-dependent manner. Activated p38 alpha is known to be involved in the stabilization of cyclooxygenase-2 mRNA in response to stimuli such as lipopolysaccharide; however, in the setting of oxidized LDL-induced p38 alpha activation, COX-2 mRNA levels were not affected. Taken together, the data imply a potential role for p38 alpha activation in lipid-associated inflammatory processes.
Atherosclerosis 2001 Oct
PMID:Inhibition of the mitogen activated protein kinase, p38 alpha, prevents proinflammatory cytokine induction by human adherent mononuclear leukocytes in response to lipid loading. 1158 11

Peroxynitrite, a marker of oxidative stress, is elevated in conditions associated with vascular endothelial cell dysfunction, such as atherosclerosis, preeclampsia, and diabetes. However, the effects of peroxynitrite on endothelial cell function are not clear. The endothelium-derived enzymes nitric oxide synthase (NOS) and prostaglandin H synthase (PGHS) mediate vascular reactivity and contain oxidant-sensitive isoforms (iNOS and PGHS-2) that can be induced by nuclear factor (NF)-kappaB activation. We investigated the effect(s) of peroxynitrite on NOS and PGHS pathways in endothelial cells. We hypothesized that peroxynitrite will increase levels of iNOS and PGHS-2 through activation of NF-kappaB. Western immunoblots of endothelial cells show that 3-morpholinosydnonimine (SIN-1; 0.5 mM), a peroxynitrite donor, increased iNOS protein mass, which can be inhibited by pyrroline dithiocarbamate (an NF-kappaB inhibitor) (167 +/- 24.2 vs. 78 +/- 19%, P < 0.05, n = 6). SIN-1 treatment also significantly increased NF-kappaB translocation into endothelial cell nuclei (135 +/- 10%, P < 0.05). Endothelial NOS, PGHS-1, and PGHS-2 protein levels were not altered by SIN-1. However, prostacyclin synthase protein mass, but not mRNA, was significantly reduced in SIN-1-treated endothelial cells (78 +/- 8.9%, P < 0.05). Our results illustrate novel mechanisms through which peroxynitrite may modulate vascular endothelial function.
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PMID:Peroxynitrite increases iNOS through NF-kappaB and decreases prostacyclin synthase in endothelial cells. 1178 51

The effects of ip administration of NSAIDs in experimentally induced hyperlipidemia in rats was studied. An isotonic solution of Triton WR1339 (tyloxapol) was administered ip to rats one hour after ip administration of the examined anti-inflammatory drug. After 24 h, blood was collected for the determination of plasma total cholesterol (TC), LDL and trigluceride (TG) concentrations. The NSAIDs used in our experimental model are selective or non selective COX-1 inhibitors as well as one non selective COX-2 inhibitor. Most of the drugs significantly reduced the TC, TG and LDL concentrations in the plasma of hyperlipidemic rats. While studies link atheromatosis to inflammation, our results potentially also link anti-inflammatory activity with hypolipidemia. Thus, NSAIDs not only may address the inflammatory aspect of atherosclerosis but also may contribute directly by inducing hypolipidemia.
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PMID:Experimental hyperlipidemia and the effect of NSAIDs. 1223 Dec 15

Coronary thrombosis is the most important cause of morbidity and mortality and the most severe manifestation of atherosclerosis. Knowledge of the pathophysiology of atheroma formation and the causes of atheroma accidents have allowed the development of new therapeutic measures for reducing thrombotic events after a coronary episode. Treating the thrombosis after plaque rupture is useful, but a late measure once coronary flow is disturbed. Therefore, treatment at an earlier stage, which we call athero-inflammation, a central event in atheroma progression leading to atherothrombosis, seems wise. There is evidence of an inflammatory component in the pathogenesis of atheroma rupture in acute coronary events. Earlier studies of anti-inflammatory medication have not demonstrated a reduction in thrombotic complications after an acute coronary episode. However, there are pathophysiological arguments and clinical findings that suggest that it would be advisable to include anti-inflammatory medications, especially those that inhibit preferentially COX-2, in the therapeutic arsenal for this pathology. We postulated that blocking athero-inflammation could prevent thrombosis. A pilot study was carried out in 120 patients with acute coronary syndrome without ST-segment elevation in which 60 patients were treated with meloxicam, a preferential COX-2 inhibitor. All patients received heparin and aspirin. During the stay in the coronary care unit, as well as after 90 days, meloxicam lowered composite outcomes (myocardial infarction, death and revascularization procedures) compared with the control group. These results and available pathophysiological and clinical evidence support the hypothesis of potential benefits of non-steroidal anti-inflammatory drugs with preferential inhibitory activity on COX-2 in patients with acute coronary syndromes. More trials are needed to confirm their preventive effect.
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PMID:[Role of anti-inflammatory drugs in the treatment of acute coronary syndromes. From athero-inflammation to athero-thrombosis]. 1254 93

To understand the potential role of cyclooxygenase (COX) in normal and inflammatory human diseases, we characterized the expression of COX-1 and COX-2 in biopsies of osteoarthritis, atherosclerosis, and cancer. Tissues were prepared for immunohistochemistry by standard methods, and representative cases assayed via Western blot and quantitative RT-PCR. COX-2 was not detected in normal human tissues with few exceptions. Moderate to marked COX-2 was observed in the macula densa (MD) and thick ascending limb (TAL) in human fetal kidneys, but was not detected in neonatal and adult MD and TALs. Low level, constitutive COX-2 was detected in colonic epithelium, peribronchial glands, and pancreatic ductal epithelium. Low to moderate COX-2 was detected basally in the cortex, hippocampus, hypothalamus, and spinal cord, and in reproductive tissues during ovulation, implantation and labor. No COX-2 was detected in the existing vasculature in normal tissues, and was also not expressed throughout the ductus arteriosus. COX-2 was markedly induced in human tissues of osteoarthritis, atherosclerosis and cancer. COX-2 was prominently expressed in the synovium, fibrocartilage of osteophytes, and in the blood vessels in the osteoarthritic (OA) knee joint. COX-2 was also prominently detected in the macrophages/foam cells in atherosclerotic plaques, and in the endothelium overlying and immediately adjacent to the fibrofatty lesion. Moderate- to intense COX-2 expression was consistently observed in the inflammatory cells, neoplastic lesions, and blood vessels in all epithelial-derived human cancers studied. In contrast, COX-1 was relatively ubiquitously observed in both normal and pathophysiological conditions. These data collectively imply COX-2 plays an important role in mediating a variety of inflammatory diseases, and imply COX-2 inhibitors may be effective in the prevention and/or treatment of OA, heart disease, and epithelial cancers.
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PMID:Cyclooxygenase-2 in human pathological disease. 1266 83

Infection with Chlamydia pneumoniae has been implicated as a potential risk factor for atherosclerosis. This study was designed to investigate the mechanisms of the anti-chlamydial activity of aspirin. A reporter gene assay for NF-kappa B activity, immunoblot analysis for cyclo-oxygenase (COX)-2 and radioimmunoassay for prostaglandin E(2) (PGE(2)) were performed. Following infection of HEp-2 cells with C. pneumoniae, NF-kappa B was activated, COX-2 was induced and PGE(2) was elevated. Aspirin inhibited NF-kappa B activation at a concentration of 0.1 mM, partially inhibited COX-2 induction and blocked PGE(2) synthesis completely. In addition, high doses of aspirin (1 and 2 mM) inhibited chlamydial growth in HEp-2 cells, decreasing the number and size of inclusion bodies; this effect could be overcome by adding tryptophan to the culture. Indomethacin also blocked the synthesis of PGE(2), but had no effect on COX-2 expression or chlamydial growth. These results indicate that aspirin not only has an anti-inflammatory activity through prevention of NF-kappa B activation but also has anti-chlamydial activity at high doses, possibly through depletion of tryptophan in HEp-2 cells.
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PMID:Aspirin inhibits Chlamydia pneumoniae-induced NF-kappa B activation, cyclo-oxygenase-2 expression and prostaglandin E2 synthesis and attenuates chlamydial growth. 1272 17

Anti-thrombotic therapy with aspirin, which at low doses acts as a selective inhibitor of platelet cyclooxygenase 1 (COX-1) activity, is well established. However, a major limitation of aspirin treatment is its gastrointestinal toxicity, which is thought to be linked to the suppression of COX-1-mediated production of cytoprotective prostaglandins. Selective COX-2 inhibitors are effective anti-inflammatory agents with lower gastrointestinal toxicity than aspirin. These inhibitors might also downregulate vascular and leukocyte inflammatory components that play a major part in atherothrombotic disease. However, some selective COX-2 inhibitors appear to increase cardiovascular risk. Newly developed dual COX-5-lipoxygenase (5-LOX) inhibitors share the anti-inflammatory effect and gastric safety of COX-2 inhibitors, but also inhibit COX-1-mediated platelet function and 5-LOX-mediated synthesis of gastrotoxic leukotrienes. Dual inhibitors might thus be beneficial in the treatment of atherosclerosis, where platelet-leukocyte interaction dominates the underlying inflammatory process.
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PMID:Prevention of thrombosis and vascular inflammation: benefits and limitations of selective or combined COX-1, COX-2 and 5-LOX inhibitors. 1276 24

Slow, time-dependent, irreversible, highly selective inhibitors of COX-2 such as celecoxib, etoricoxib, rofecoxib and valdecoxib, so-called coxibs, are a new group of drugs widely used in rheumatology as well as in other fields of medicine. The tolerability of these drugs is at least equivalent to that of commonly used non-selective COX inhibitors (e.g. diclofenac, ibuprofen, naproxen). The unquestionable superiority of selective COX-2 blockade includes a low risk of gastrointestinal side effects. However, similarly to the other COX inhibitors, coxibs must be carefully administered to patients with coexistent liver and renal disease, generalised atherosclerosis, ischaemic heart disease, and to the elderly and children. Pregnancy and lactation require precise monitoring of adverse effects on the fetus, neonate and infant, or discontinuation of therapy with the drug.
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PMID:[Coxibs: highly selective cyclooxygenase-2 inhibitors. Part II. Side effects]. 1286 1

Antithrombotic therapy is the cornerstone of the treatment of acute coronary syndromes, but there is now evidence which indicates that by blocking inflammation, thrombosis and thus, acute coronary events, could be lowered. The concept of athero-inflammation emerges as the meeting point of different morbidities; dyslipemia, diabetes, hypertension, obesity, immunity, infection, hyperhomocyteinemia, smoking, etc. usual named as risk factors. Thus, beside specific drugs, earliest treatment, in the stage of inflammation, using anti-inflammatory drugs, should be considered since in patients with increased risk of acute coronary process are likely to have many point of origen throughout the coronary arteries. There are a body of evidences for supporting the potential of anti-inflammatory therapy to the prevention of inflammation and atherosclerosis. COX-2 inhibition may decrease endothelial inflammation reducing monocytes infiltration improving vascular cells function, plaque stability and probably resulting in a decrease of coronary atherothrombotic events.Trials including large numbers of patients in prospective double-blind randomized studies worthwhile to confirm the efficacy of NSAID, mainly, COX-2 inhibitors, together with aspirin in the prevention of coronary events in patients with acute coronary disease.
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PMID:Acute coronary disease Athero-Inflammation: Therapeutic approach. 1290 61


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