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)

Perivascular manipulation promoted by the positioning of a silicone collar around the common carotid arteries causes local inflammation and has been suggested as an animal model of atherosclerosis. This manipulation induces biochemical and morphological changes that are similar to those observed in the early stage of atherosclerosis in humans. Based on evidences showing that atherosclerosis is associated with cognitive deficits in humans, we presently investigated the temporal consequences of the bilateral positioning of silicone collars around the common carotid arteries (n = 15) on inhibitory avoidance memory retention in male Wistar rats tested in the elevated T-maze. The effects of this procedure were compared to those observed in sham-operated animals (n = 15) and to those observed in animals submitted to permanent bilateral occlusion of the common carotid arteries (n = 16). Additionally we studied the effects of the pretreatment with the non-selective anti-inflammatory drug indomethacin (n = 13) or the selective COX-2 inhibitor celecoxib (n = 12) and compared the effects to those of the pretreatment with vehicle (n = 11). The results showed that the silicone collar implants induced deficits in memory retention when animals were tested 2 and 4, but not 15 or 30, days after surgery. Permanent bilateral occlusion of the common carotid arteries impaired avoidance retention up to 30 days after surgery. Pretreatment with indomethacin (2 mg/kg/day) or celecoxib (5 mg/kg/day) post surgery and up to 3 days thereafter did not prevent memory deficits caused by silicone collar implants. Our data suggest that the prostanoids that participate in the inflammatory process triggered by the placement of the silicone collar do not seem responsible for the deficit in memory retention observed during the first days after collar placement.
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PMID:Inhibitory avoidance memory retention in the elevated T-maze is impaired after perivascular manipulation of the common carotid arteries. 1582 77

Suppression of prostacyclin (PGI2) biosynthesis may explain the increased incidence of myocardial infarction and stroke which has been observed in placebo controlled trials of cyclooxygenase (COX)-2 inhibitors. Herein, we examine if COX-2-derived PGI2 might condition the response of the vasculature to sustained physiologic stress in experimental models that retain endothelial integrity. Deletion of the PGI2 receptor (IP) or suppression of PGI2 with the selective COX-2 inhibitor, nimesulide, both augment intimal hyperplasia while preserving luminal geometry in mouse models of transplant arteriosclerosis or flow-induced vascular remodeling. Moreover, nimesulide or IP deletion augments the reduction in blood flow caused by common carotid artery ligation in wild-type mice. Generation of both thromboxane (Tx)A2 and the isoprostane, 8, 12 -iso iPF(2alpha)-VI, are increased in the setting of flow reduction and the latter increases further on administration of nimesulide. Deletion of the TxA2 receptor (TP) reduces the hyperplastic response to nimesulide and carotid ligation, despite further augmentation of TP ligand production. Suppression of COX-2-derived PGI2 or deletion of IP profoundly influences the architectural response of the vasculature to hemodynamic stress. Mechanism based vascular remodeling may interact with a predisposition to hypertension and atherosclerosis in contributing to the gradual transformation of cardiovascular risk during extended periods of treatment with selective inhibitors of COX-2.
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PMID:COX-2-derived prostacyclin modulates vascular remodeling. 1590 61

Non-selective inhibition of cyclooxygenase (COX) has been reported to reduce atherosclerosis in both rabbit and murine models. In contrast, selective inhibition of COX-2 has been shown to suppress early atherosclerosis in LDL-receptor null mice but not more advanced lesions in apoE deficient (apoE(-/-)) mice. We investigated the efficacy of the novel COX inhibitor indomethacin phenethylamide (INDO-PA) on the development of different stages of atherosclerotic lesion formation in female apoE(-/-) mice. INDO-PA, which is highly selective for COX-2 in vitro, reduced platelet thromboxane production by 61% in vivo, indicating partial inhibition of COX-1 in vivo. Treatment of female apoE(-/-) mice with 5mg/kg INDO-PA significantly reduced early to intermediate aortic atherosclerotic lesion formation (44 and 53%, respectively) in both the aortic sinus and aorta en face compared to controls. Interestingly, there was no difference in the extent of atherosclerosis in the proximal aorta in apoE(-/-) mice treated from 11 to 21 weeks of age with INDO-PA, yet there was a striking (76%) reduction in lesion size by en face analysis in these mice. These studies demonstrate the ability of non-selective COX inhibition with INDO-PA to reduce early to intermediate atherosclerotic lesion formation in apoE(-/-) mice, supporting a role for anti-inflammatory approaches in the prevention of atherosclerosis.
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PMID:Inhibition of cyclooxygenase with indomethacin phenethylamide reduces atherosclerosis in apoE-null mice. 1595 Jan 96

The aim of this study was to assess the effect of ZR on the growth of cultured human hepatic myofibroblast cells (hMF). The zedoary (Zedoariae Rhizoma) made from the dried rhizome of Curcuma zedoaria Roscoe is an herbal drug used as an aromatic stomachic. The plant is a perennial herb which is natively distributed throughout Korea and is a traditional Korean herbal medicine. Zedoariae rhizoma is a bioactive traditional medicine with anti-tumor, anti-atherosclerosis, anti-inflammation, and growth-regulating properties. During the course of liver fibrogenesis, hMF, mostly derived from hepatic stellate cells, proliferate and synthesize excessive amounts of extracellular matrix components. To evaluate the antiproliferative effect of a traditional herbal medicine, Zedoariae rhizoma water extracts (ZR) was examined on the growth inhibition of hMF since proliferation of hMF is known to be central for the development of fibrosis during liver injury, and factors that may limit their growth are potential antifibrotic agents. The aim of this study was to test the effects of ZR on the proliferation in cultured hMF. hMF were obtained by outgrowth from human liver explants. ZR markedly reduced serum driven cell proliferation, as assessed by nuclear autoradiography experiments and measurement of actual cell growth. Growth inhibition was totally reversed after removal of the ZR. ZR potently inhibited hMF growth (IC50 = 8.5 microg/ml), in a pertussis toxin-insensitive manner. Analysis of the mechanisms involved in growth inhibition revealed that ZR rapidly increased prostaglandin E2 production and in turn cAMP, which inhibited hMF proliferation, did not affect cAMP levels. Production of cAMP by ZR was abolished by NS-398, a selective inhibitor of cycloxygenase (COX)-2. Also, ZR potently induced COX-2 protein expression. Blocking COX-2 by NS-398 blunted the antiproliferative effect of ZR. We conclude that ZR inhibits proliferation of hMF, probably via an intracellular mechanism, through early COX-2-dependent release of prostaglandin E2 and cAMP, and delayed COX-2 induction. Our results indicated a novel role for ZR as a growth inhibitory mediator and pointed out its potential involvement in the negative regulation of liver fibrogenesis. The results that ZR exhibits potent antiproliferative and antifibrogenic effects toward hMF, indicated that ZR might have therapeutic implications in chronic liver disease.
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PMID:The inhibitory effect of a Korean herbal medicine, Zedoariae rhizoma, on growth of cultured human hepatic myofibroblast cells. 1596 8

Cyclooxygenase (COX) 2 is expressed in atherosclerotic lesions. We have previously reported that selective inhibition of COX-2 reduces early atherosclerosis in LDLR deficient mice. To examine the role of COX-2 in atherosclerosis in other mouse models, we studied the effects of selective COX-2 inhibition (by rofecoxib and NS-398) and nonselective COX inhibition (by indomethacin) on early atherosclerotic lesion formation in apolipoprotein E-deficient (apoE(-/-)) mice. Selective COX-2 and nonselective COX inhibition reduced atherosclerosis in female apoE(-/-) mice by 35-38% and 38-51% in the proximal and en face aortas, respectively. Next we investigated the role of macrophage COX-2 by transplanting COX-2(-/-) fetal liver cells into C57BL/6 mice and challenging the mice with an atherogenic diet. Genetic deletion of COX-2 from hematopoietic cells reduced atherosclerosis by 51%. In addition, LPS activated COX-2(-/-) macrophages had decreased expression of monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-alpha (TNFalpha). The results demonstrate that selective inhibition of COX-2 and elimination of COX-2 from macrophages significantly reduces early atherosclerotic lesion formation in apoE-deficient and C57BL/6 mice. These results are compatible with COX-2 expression by macrophages having a proatherogenic role, and support the potential of anti-inflammatory therapeutic approaches for atherosclerosis.
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PMID:Cyclooxygenase-2 promotes early atherosclerotic lesion formation in ApoE-deficient and C57BL/6 mice. 1604 51

Impairment of endothelium-dependent vasodilation is associated with the initiation and development of atherosclerosis. Vasodilator prostanoids constitute a protective mechanism in maintaining normal vasomotor function. In the current study, we determined the effect of in vitro vitamin E supplementation at physiologically relevant concentrations (10-60 micromol/L) on the production of the vasodilator prostanoids prostaglandin I(2) (PGI(2); prostacyclin) and prostaglandin E(2)(PGE(2)) by human aortic endothelial cells (HAECs) as well as its underlying mechanism. Results showed that vitamin E dose dependently (10-40 micromol/L) increased the production of both prostanoids by HAECs. This was associated with a dose-dependent (10-40 micromol/L) upregulation of cytosolic phospholipase A(2) (cPLA(2)) expression and arachidonic acid release. In contrast, vitamin E dose dependently (10-60 micromol/L) inhibited cyclooxygenase (COX) activity but did not affect the expression of either COX-1 or COX-2, indicating that the effect of vitamin E on COX activity was post-translational. Thus, vitamin E had opposing effects on the 2 key enzymes in prostanoid biosynthesis; at the concentrations used in this study, this resulted in a net increase in the production of vasodilator prostanoids. The vitamin E-induced increase in PGI(2) and PGE(2) production may contribute to its suggested beneficial effect in preserving endothelial function.
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PMID:Vitamin E increases production of vasodilator prostanoids in human aortic endothelial cells through opposing effects on cyclooxygenase-2 and phospholipase A2. 1604 7

Vascular smooth muscle cell proliferation and migration play an important role in the pathophysiology of several vascular diseases, including atherosclerosis. Prostaglandins that have been implicated in this process are synthesized by two isoforms of cyclooxygenase (COX), with the expression of the regulated COX-2 isoform increased in atherosclerotic plaques. Bradykinin (BK), a vasoactive peptide increased in inflammation, induces the formation of prostaglandins through specific receptor activation. We hypothesized that BK plays an important role in the regulation of COX-2, contributing to the increase in production of prostaglandins in vascular smooth muscle cells. Herein we examined the signaling pathways that participate in the BK regulation of COX-2 protein levels in primary cultured aortic vascular smooth muscle cells. We observed an increase in COX-2 protein levels induced by BK that was maximal at 24 h. This increase was blocked by a B2 kinin receptor antagonist but not a B1 receptor antagonist, suggesting that the B2 receptor is involved in this pathway. In addition, we conclude that the activation of mitogen-activated protein kinases p42/p44, protein kinase C, and nitric oxide synthase is necessary for the increase in COX-2 levels induced by BK because either of the specific inhibitors for these enzymes blocked the effect of BK. Using a similar approach, we further demonstrated that reactive oxygen species and cAMP were not mediators on this pathway. These results suggest that BK activates several intracellular pathways that act in combination to increase COX-2 protein levels. This study suggests a role for BK on the evolution of the atheromatous plaque by virtue of controlling the levels of COX-2.
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PMID:Cyclooxygenase-2 induction by bradykinin in aortic vascular smooth muscle cells. 1614 55

Selective COX-2 inhibitors increase the risk of myocardial infarction and stroke. This has been attributed to their ability to inhibit endothelial COX-2 derived prostacyclin (PGI2) but not platelet COX-1 derived thromboxane A2 (TXA2). On the other hand, aspirin blocks both COX-1 and COX-2 enzymes without decreasing PGI2 but blocks TXA2 synthesis that explains its beneficial action in the prevention of coronary heart disease (CHD). The inhibitory action of aspirin on COX-1 and COX-2 enzymes enhances the tissue concentrations of dihomo-gamma-linolenic acid (DGLA), arachidonic acid, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). These fatty acids form precursors to PGE1, PGI2, PGI3, lipoxins (LXs), and resolvins that have anti-inflammatory actions. In contrast, increase in the concentrations of DGLA, AA, EPA, and DHA is much less with specific COX-2 inhibitors since they do not block the formation of eicosanoids through COX-1 pathway. COX-2 inhibitors interfere with the formation of LXs and resolvins that have neuroprotective and cardioprotective actions. EPA and PGI2 have anti-arrhythmic action. EPA, DHA, and AA augment eNO formation that prevents atherosclerosis. This suggests that COX-2 inhibitors increase cardiovascular and stroke risk by interfering with the formation of eNO, PGI2, LXs, and resolvins and implies that combining EFAs with COX-2 inhibitors could prevent these complications.
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PMID:Can COX-2 inhibitor-induced increase in cardiovascular disease risk be modified by essential fatty acids? 1619 Jan 33

Atherosclerotic plaque rupture is promoted by metalloproteinase (MMP)-2 and MMP-9, enzymes that degrade the fibrous cap leading to plaque erosion. MMP biosynthesis is mediated by prostaglandin (PG)E2, the product of cyclooxygenase (COX)-2/inducible PGE synthase (mPGES) activity. We have recently reported the overexpression of COX-2/mPGES-1 in vulnerable plaques as a basis of MMP-mediated plaque instability. Hypercholesterolemia and hypertension are two important risk factors for atherosclerosis. Recent trial showed that statins and AT1 receptor blockers significantly reduce the incidence of cardiovascular events in humans. Since anti-inflammatory effects have been reported in association to therapy with statins or AT1 receptor blockers, in two different studies we hypothesized that these drugs can stabilize atherosclerotic plaques through modulation of COX-2/mPGES-1-dependent MMP biosynthesis. Our data demonstrated the stabilizing effect of atherosclerotic plaques by simvastatin or irbesartan, that is due, at least in part, to the reduction of inflammatory burden and suppression of PGE2-dependent metalloproteinases release.
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PMID:Pharmacological modulation of plaque instability. 1621 85

Coxibs, such as rofecoxib, celecoxib, and valdecoxib, selectively inhibit cyclooxygenase (COX)-2, the mainly inducible, pro-inflammatory COX isoform. Unlike traditional non-steroidal anti-inflammatory drugs (NSAIDs) most coxibs do not significantly inhibit COX-1 and are therefore less toxic to the gastrointestinal tract. Hence, coxibs widely replaced traditional NSAIDs for treatment of arthritis and other painful inflammatory conditions. In many, but not all, clinical studies, coxibs became associated with higher risks of myocardial infarction (MI) and stroke. Several mechanisms may be involved in the pathogenesis of such complications. First, selective inhibition of COX-1 lowers platelet synthesis of thromboxane (TXA(2)), a thrombogenic and atherogenic eicosanoid. Selective inhibition of COX-2 limits endothelial cell synthesis of prostacyclin (PGI(2)), an arachidonic acid product that opposes the effects of thromboxane. In apoE-/- mice, interruption of TXA(2) signaling by deletion of its receptor (TP) limits atherogenesis, whereas interruption of PGI2 signaling by deletion of its receptor (IP) accelerates atherogenesis. This suggests that selective inhibition of COX-2 can disrupt the physiological balance between thromboxane and prostacyclin and thus increase atherosclerosis, thrombogenesis, and the risk of cardiovascular complications. Second, COX inhibition can raise levels of arachidonic acid, which can inhibit mitochondrial oxidative phosphorylation (OXPHOS) and increase OXPHOS generation of reactive oxygen species. Several NSAIDs, including coxibs and meloxicam, directly uncouple or inhibit OXPHOS. Studies of apoE-/- mice indicate that mitochondrial dysfunction plays an early role in atherogenesis. Third, many NSAIDs exhibit COX-independent properties. For example, in animal models, short-term treatment with celecoxib reduces monocyte chemotaxis by reducing expression of monocyte chemoattractant protein (MCP)-1. However, long-term treatment results in the opposite effect and accelerates atherogenesis. In conclusion, to reduce the risk of cardiovascular complications during long-term coxib therapy, low-dose aspirin supplementation should be considered. An alternative is to use a less COX-2-selective inhibitor such as meloxicam. Genotyping of -765 alleles of the COX-2 gene promoter and examining the polymorphism of other genes involved in eicosanoid metabolism or NSAID degradation may become helpful in predicting patients who are at higher risk of cardiovascular complications during selective COX-2 inhibitor therapy.
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PMID:Cardiovascular complications of non-steroidal anti-inflammatory drugs. 1625 52


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