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)

The migration and proliferation of vascular smooth muscle cells (SMCs) are known to play roles in the pathogenesis of atherosclerosis. Therapy with a reductase inhibitor of 3-hydroxy-3 methylglutaryl coenzyme A (HMG-CoA) ("statin") produces significant alterations in various SMC functions. The objectives of the present study were to determine whether pitavastatin, a new chemically synthesized and powerful statin, can affect angiotensin II (Ang II)- and platelet-derived growth factor (PDGF)-induced migration and proliferation of cultured rat vascular SMCs. The effect of pitavastatin on cell viability was also examined in these cells. Migration was evaluated by the Boyden's chamber method using microchemotaxis chambers. As expected, Ang II and PDGF BB potently stimulated cell migration in a concentration-dependent manner. Pitavastatin significantly inhibited Ang II (10(-6) mol/l)-induced migration at the concentrations of 10(-8) and 10(-7) mol/l. Pitavastatin also inhibited PDGF BB (1 ng/ml)-induced migration at concentrations between 10(-9) and 10(-8) mol/l in a relatively concentration-dependent manner. This statin modestly but significantly inhibited Ang II (10(-6) mol/l)- and PDGF BB (1 ng/ml)-induced DNA synthesis at concentrations between 10(-9) and 10(-7) mol/l. In addition, pitavastatin clearly inhibited Ang II (10(-6) mol/l)- and PDGF BB (1 ng/ml)-induced increases of cell number at concentrations between 10(-9) and 10(-7) mol/l. Pitavastatin did not affect lactate dehydrogenase release from these cells at the concentrations used in this experiment. In a trypan blue exclusion test, dead cells stained with trypan blue were not found 24 h after treatment with 10(-9), 10(-8) or 10(-7) mol/l of pitavastatin. These findings suggest that pitavastatin suppresses the migration and proliferation stimulated by Ang II and PDGF BB without affecting cell viability. Pitavastatin may exert an anti-atherogenic effect, in part, through these mechanisms.
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PMID:Inhibition of migration and proliferation of rat vascular smooth muscle cells by a new HMG-CoA reductase inhibitor, pitavastatin. 1204 44

Troglitazone, a thiazolizidinedione, has recently been reported to possess anti-arteriosclerotic properties. To evaluate mechanisms underlying the anti-arteriosclerotic effects of troglitazone, we examined the effect of troglitazone on growth, expression of growth factors, and insulin signaling in vascular smooth muscle cells (VSMC) from spontaneously hypertensive rats (SHR) which produce angiotensin II (Ang II) in a homogeneous culture. Troglitazone inhibited basal and serum-stimulated DNA synthesis and inhibited increases in the number of VSMC from SHR and normotensive Wistar-Kyoto (WKY) rats. Its inhibition was greater in VSMC from SHR. Troglitazone abolished DNA synthesis in response to Ang II in VSMC from both rat strains and markedly inhibited DNA synthesis in response to epidermal growth factor (EGF) and platelet-derived growth factor (PDGF)-AA in VSMC from SHR. Troglitazone did not alter the expression of transforming growth factor (TGF)-beta1, PDGF A-chain, or basic fibroblast growth factor (bFGF) mRNAs in VSMC from WKY rats, but it markedly decreased expression of these growth factor mRNAs in VSMC from SHR. Troglitazone markedly decreased basal and Ang II-stimulated expression of extracellular signal-regulated kinase proteins in VSMC from both rat strains. Troglitazone abolished Ang II-induced suppression of phosphatidilinositol 3-kinase (PI3-kinase) activity, insulin receptor substrate-1 (IRS-1) associated tyrosine phosphorylation, and IRS-1 associated p85 levels in VSMC from WKY rats. Basal PI3-kinase activity, tyrosine phosphorylation of IRS-1, and IRS-1 associated p85 levels were lower in VSMC from SHR than in cells from WKY rats. Troglitazone significantly increased PI3-kinase activity, IRS-1 associated tyrosine phosphorylation, and IRS-1 associated p85 levels in VSMC from SHR. These results indicate that troglitazone produce its anti-arteriosclerotic effects through suppression of the action of growth-promoting factors including Ang II, and that troglitazone inhibits Ang II-induced suppression of insulin signaling in VSMC from SHR, suggesting that tissue Ang II may lead to insulin resistance and to arteriosclerosis in hypertension. Troglitazone may be useful in the treatment of insulin resistance as well as of hypertensive vascular diseases.
Atherosclerosis 2002 Aug
PMID:Troglitazone inhibits growth and improves insulin signaling by suppression of angiotensin II action in vascular smooth muscle cells from spontaneously hypertensive rats. 1205 69

Resistance to the metabolic actions of insulin is thought to play a determining role in the aetiology of a great variety of disorders, including essential hypertension, accelerated atherosclerosis and cardiomyopathies. ACE inhibitors are recognised as being highly effective therapy for hypertension and cardiac insufficiency, and have a more beneficial effect on survival rate than expected on the basis of known mechanisms of action. The mechanism responsible for these extremely positive effects are just beginning to be understood and appear to be linked to the effects these drugs have on metabolism. The relationship between the insulin and angiotensin II (Ang II) signalling pathways needs to be fully clarified in order to prevent or correct the target organ damage resulting from changes in the cross-talk of these two hormonal systems. In recent years, Ang II has been shown to play a central role in cardiovascular and neuroendocrine physiology as well as in cellular cycle control. Moreover, the fact that Ang II utilises the insulin-receptor substrate (IRS)-1 to relay signals towards their intracellular destination, provides the biochemical explanation of how these two systems interact in a healthy organism and in a diseased one. Since it is overactivity of the renin-angiotensin system that seems to impair the intracellular response to insulin signalling, cardiovascular drugs that modulate the cellular transmission of Ang II have attracted particular interest. As well as the already widely-used ACE inhibitors, selective blockers of the Ang II type 1 receptor (AT(1)) have been shown to be clinically effective in the control of haemodynamic parameters, but with perhaps a less striking effect on glucose homeostasis. Many trials have investigated the effect of Ang II blockade on systemic glucose homeostasis. The inhibition of Ang II by ACE-inhibitors frequently showed a positive effect on glycaemia and insulin sensitivity, while information on the effects of AT(1) receptor antagonists on glucose homeostasis is more limited and controversial. An important limitation of these studies has been the short treatment and follow-up periods, even for the 'so called' long-term studies which were only 6 months. Several investigators have focused on the effects of the nuclear factors involved in gene transcriptions, especially with respect to the agonists/antagonists of peroxisome proliferator-activated receptors (PPARs) and their intriguing interconnections with the insulin and Ang II subcellular pathways. In fact, in vitro and in vivo experimental studies have shown that thiazolidinediones (selective PPAR-gamma ligands) are not only powerful insulin sensitisers, but also have anti-hypertensive and anti-atherosclerotic properties. In addition to conventional pharmacological approaches, attempts have been made to use genetic transfer in the treatment of cardiovascular and metabolic disorders. The development of powerful viral vectors carrying target genes has allowed us to restore the expression/function of specific proteins involved in the cellular mechanism of insulin resistance, and research now needs to move beyond animal models. Although a clearer picture is now emerging of the pathophysiological interaction between insulin and Ang II, especially from pre-clinical studies, there is much to be done before experimental findings can be used in daily clinical practice.
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PMID:The role of the angiotensin system in cardiac glucose homeostasis: therapeutic implications. 1207 80

Angiotensin II (Ang II), the most important component of the renin-angiotensin system, is usually associated with hypertension and renal failure. Through its pro-inflammatory actions, it also plays an important role in each step of the development of atherosclerotic plaques and plaque rupture. Ang II stimulates the expression of nuclear factor-kappaB (NFkappaB), a transcription factor which regulates gene expression of inflammatory cytokines such as interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1). Ang II type 1 receptors (AT1) and angiotensin converting enzyme (ACE) are dramatically increased in atherosclerotic plaques, particularly in monocytes at the fibrous cap. Thus, in multiple ways, Ang II is a critical factor in atherosclerotic plaque formation, inflammation and plaque stability. ACE inhibitors and AT1R inhibitors could therefore be appropriate therapeutic agents in the treatment of atherosclerosis.
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PMID:Angiotensin II as a pro-inflammatory mediator. 1209 Jul 26

It is now well established that vascular inflammation is an independent risk factor for the development of atherosclerosis. In otherwise healthy patients, chronic elevations of circulating interleukin-6 or its biomarkers are predictors for increased risk in the development and progression of ischemic heart disease. Although multifactorial in etiology, vascular inflammation produces atherosclerosis by the continuous recruitment of circulating monocytes into the vessel wall and by contributing to an oxidant-rich inflammatory milieu that induces phenotypic changes in resident (noninflammatory) cells. In addition, the renin-angiotensin system (RAS) has important modulatory activities in the atherogenic process. Recent work has shown that angiotensin II (Ang II) has significant proinflammatory actions in the vascular wall, inducing the production of reactive oxygen species, inflammatory cytokines, and adhesion molecules. These latter effects on gene expression are mediated, at least in part, through the cytoplasmic nuclear factor-kappaB transcription factor. Through these actions, Ang II augments vascular inflammation, induces endothelial dysfunction, and, in so doing, enhances the atherogenic process. Our recent studies have defined a molecular mechanism for a biological positive-feedback loop that explains how vascular inflammation can be self-sustaining through upregulation of the vessel wall Ang II tone. Ang II produced locally by the inflamed vessel induces the synthesis and secretion of interleukin-6, a cytokine that induces synthesis of angiotensinogen in the liver through a janus kinase (JAK)/signal transducer and activator of transcription (STAT)-3 pathway. Enhanced angiotensinogen production, in turn, supplies more substrate to the activated vascular RAS, where locally produced Ang II synergizes with oxidized lipid to perpetuate atherosclerotic vascular inflammation. These observations suggest that one mechanism by which RAS antagonists prevent atherosclerosis is by reducing vascular inflammation. Moreover, antagonizing the vascular nuclear factor-kappaB and/or hepatic JAK/STAT pathways may modulate the atherosclerotic process.
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PMID:Vascular inflammation and the renin-angiotensin system. 1217 84

Interleukin-8 (IL-8) is a potent chemotactic factor that has been implicated in atherogenesis. HMG-CoA reductase inhibitors (statins) may reduce the cardiovascular risk and vulnerability of atherosclerotic plaque through nonlipid mechanisms such as inhibition of cytokine expression. In this study, we investigated the effects of statins on IL-8 synthesis in human vascular smooth muscle cells (VSMCs). Addition of angiotensin II (Ang II) increased IL-8 production in VSMCs in a time (0-24 h)- and dose (10(-8)-10(-6) mol/l)-dependent manner with increased IL-8 mRNA accumulation. The Ang II type 1 receptor (AT1R) antagonist candesartan, but not the Ang II type 2 receptor (AT2R) antagonist PD123319, significantly blocked Ang II-induced IL-8 production. Addition of fluvastatin decreased the basal and Ang II-induced IL-8 production in VSMCs in a dose (10(-8)-10(-5) mol/l)-dependent manner with a decrease in IL-8 mRNA accumulation. The effect of fluvastatin on IL-8 production was completely reversed in the presence of mevalonate or geranylgeranyl-pyrophosphate, but not in the presence of squalene or farnesyl-pyrophosphate. Lipophilic cerivastatin also significantly decreased IL-8 production, while hydrophilic pravastatin showed no effect on IL-8 levels. In conclusion, we demonstrated for the first time that Ang II increased IL-8 production and fluvastatin decreased the basal and Ang II-induced IL-8 production in human VSMCs. These findings suggested that Ang II may exacerbate atherosclerosis through induction of IL-8 in VSMCs, while statins may exert therapeutic effects by modulating IL-8 synthesis in patients with atherosclerotic disease.
Atherosclerosis 2002 Nov
PMID:Regulation of interleukin-8 expression by HMG-CoA reductase inhibitors in human vascular smooth muscle cells. 1220 70

Angiotensin II (Ang II) is a multifunctional hormone that influences the function of cardiovascular cells through a complex series of intracellular signaling events initiated by the interaction of Ang II with AT1 and AT2 receptors. AT1 receptor activation leads to cell growth, vascular contraction, inflammatory responses and salt and water retention, whereas AT2 receptors induce apoptosis, vasodilation and natriuresis. These effects are mediated via complex, interacting signaling pathways involving stimulation of PLC and Ca2+ mobilization; activation of PLD, PLA2, PKC, MAP kinases and NAD(P)H oxidase, and stimulation of gene transcription. In addition, Ang II activates many intracellular tyrosine kinases that play a role in growth signaling and inflammation, such as Src, Pyk2, p130Cas, FAK and JAK/STAT. These events may be direct or indirect via transactivation of tyrosine kinase receptors, including PDGFR, EGFR and IGFR. Ang II induces a multitude of actions in various tissues, and the signaling events following occupancy and activation of Ang receptors are tightly controlled and extremely complex. Alterations of these highly regulated signaling pathways may be pivotal in structural and functional abnormalities that underlie pathological processes in cardiovascular diseases such as cardiac hypertrophy, hypertension and atherosclerosis.
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PMID:Recent advances in angiotensin II signaling. 1221 72

Angiotensin II (Ang II) may be a key molecule in the development of atherosclerosis. Because the incidence of coronary atherosclerosis in premenopausal women is lower than that observed in men or postmenopausal women, we have investigated the effect of estrogens on Ang II-induced leukocyte recruitment in vivo using intravital microscopy in the rat mesenteric microcirculation. Superfusion for 60 minutes with Ang II induced a significant increase in leukocyte rolling flux, adhesion, and emigration. Administration of 17-beta-estradiol (17-beta-E) after 30 minutes of Ang II superfusion produced a reduction of these leukocyte responses by 55.1%, 72.7%, and 70.9%, respectively, an additional 30 minutes later. The effect observed with 17-beta-E was receptor-mediated and specific. 17-beta-E superfusion did not modify either L-NAME or indomethacin-induced leukocyte responses. Inhibitory responses caused by 17-beta-E were not altered by either 7-nitroindazole or actinomycin D cosuperfusion. Stimulation of endothelial cells with 17-beta-E caused a rapid and dose-dependent release of prostacyclin. Finally, tamoxifen or ICI 182,780 administration provoked a significant increase in leukocyte-endothelial cell interactions 90 minutes later, which were significantly attenuated by systemic preadministration with an Ang II AT(1) receptor antagonist. Tamoxifen-induced leukocyte responses were also reduced by systemic pretreatment with an anti-P-selectin mAb and an anti-CD18 mAb. Hence, the antiatherogenic effects of estrogens may be mediated by inhibition of Ang II-induced leukocyte recruitment through endothelial NO and prostacyclin release. Furthermore, scarcity of estrogens resulted in decreased levels of vasodilators and the exposure of the endothelium to the deleterious action of Ang II, which may explain the higher incidence of coronary atherosclerosis in men and postmenopausal women.
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PMID:Estrogens inhibit angiotensin II-induced leukocyte-endothelial cell interactions in vivo via rapid endothelial nitric oxide synthase and cyclooxygenase activation. 1248 Aug 15

Aortic aneurysm is a chronic degenerative condition associated with atherosclerosis. Recent studies have revealed that angiotensin (Ang) II plays important roles in atherosclerosis. In this study, to investigate the relationship between aortic aneurysm and Ang II, we measured the activities of the angiotensin (Ang) II-forming enzymes, angiotensin converting enzyme (ACE) and chymase-like enzyme, in human aneurysmal and control aortae. Aneurysmal aortic specimens were obtained from 16 aneurysm patients and control aortic specimens were obtained from 16 patients who underwent coronary artery bypass surgery (8 patients in each group were administered ACE inhibitors). The ACE and chymase-like enzyme activities were determined using extracts from vascular tissues. Both the ACE and chymase-like enzyme activities in the aneurysmal aortae were significantly higher than those in the control aortae (p < 0.01). In the patients treated with ACE inhibitors, the ACE activity in the aneurysmal aortae tended to be low, but the chymase-like enzyme activity tended to be high. In the aneurysmal aortae, the chymase-like enzyme activity in the adventitia was significantly higher than that in the intimal or medial layers (p < 0.01), while differences in ACE activity were not observed. Our results suggest that increases in local Ang II formation induced by chymase-like enzymes may play important roles in the pathogenesis of aneurysmal formation.
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PMID:Possible roles of angiotensin II-forming enzymes, angiotensin converting enzyme and chymase-like enzyme, in the human aneurysmal aorta. 1248 3

Insulin resistance is involved in the pathogenesis of type 2 diabetes, hypertension, and atherosclerosis. Angiotensin (Ang) converting enzyme inhibitors and Ang II type 1 receptor antagonists improve insulin resistance in patients with essential hypertension, which suggest that tissue Ang II is involved in insulin resistance in patients with hypertension. To investigate the participation of tissue Ang II in insulin resistance associated with hypertension, we evaluated the Ang II-generating system in leukocytes and its relation to insulin resistance in patients with essential hypertension. Eighteen patients with essential hypertension participated in this study. Ang II was separated from leukocytes by reversed-phase high-performance liquid chromatography and measured by radioimmunoassay. Insulin resistance was evaluated by determining the steady-state of plasma glucose (SSPG) concentration. The Ang I- and Ang II-generating activities were evaluated in human leukocytes. Human leukocytes have Ang I- and Ang II-generating activities. The Ang II-generating activity was significantly inhibited by pepstatin A. Leukocyte Ang II level does not correlate with BP or plasma Ang II level in patients with essential hypertension. Leukocyte Ang II level strongly correlates with SSPG concentration, and significantly correlates with body mass index and plasma insulin, and with leptin levels in patients with essential hypertension. Leukocyte Ang II may be directly associated with insulin resistance.
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PMID:Leukocyte angiotensin II levels inpatients with essential hypertension:relation to insulin resistance. 1255 79


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