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)

Abnormal smooth muscle cell (SMC) proliferation is observed in several pathological situations such as atherosclerosis, pulmonary hypertension, and venous pathologies, resulting in a thickening of the vessel wall. If endothelial cells have been assumed to play a role in the triggering of this proliferation, no direct evidence is available. As ischemia is often linked to these situations, we exposed human umbilical vein endothelial cells (HUVEC) to hypoxia. The HUVEC-conditioned medium was then added to SMC and the proliferation of these cells was measured. We observed a pro-proliferative activity for SMC of the hypoxic HUVEC-conditioned medium but not of the normoxic HUVEC one. This pro-proliferative activity could not be inhibited if HUVEC were treated with cycloheximide but was blocked if the synthesis of prostaglandins by HUVEC was inhibited during hypoxia. PGD2, and especially PGF2 alpha at the concentration found in the hypoxic HUVEC-conditioned medium, were demonstrated to have a mitogenic effect on SMC. PGE2 also showed a pro-proliferative activity but at higher concentrations. In addition, the kinetics of increase in SMC proliferation induced by a mixture of the four prostaglandins at the corresponding concentrations was the same as the one observed with hypoxic HUVEC-conditioned medium. However, when tested on fibroblasts which do not respond to PGF2 alpha, hypoxic HUVEC-conditioned medium also had a pro-proliferative activity. In addition, anti-bFGF antibodies but not anti-PDGF blocked the mitogenic activity of this conditioned medium for SMC. Finally, the mitogenic effects of PGF2 alpha and of bFGF on SMC are additive. These results indicate that bFGF is probably also involved. These results indicate that these prostaglandins act in synergy with bFGF and are the molecules responsible for the pro-proliferative activity observed in hypoxic HUVEC-conditioned medium. We propose that these findings can explain the excessive growth of SMC in blood vessels following chronic ischemic situations.
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PMID:Hypoxia stimulates human endothelial cells to release smooth muscle cell mitogens: role of prostaglandins and bFGF. 802 Jun 5

Thrombin, the final product of blood coagulation cascade, shows several effect on the vessel-wall cells. However the effects may be regulated by several thrombin receptors on the endothelium. They include thrombomodulin (TM), protease-Nexin, heparin-like molecule-antithrombin III complex. These binding sites do not transduce the signal of thrombin. Especially TM converts thrombin from a procoagulant protease to an anticoagulant. Recently new thrombin receptor was identified on the endothelium and platelets. Through this receptor, thrombin induces activations both on platelet end-endothelium. In brief platelets aggregate and release several factors including serotonin, PDGF, platelet factor4, beta-thromboglobulin on the stimulation by thrombin. The endothelium release t-PA inhibitor; PAI-1, prostacyclin and endothelin. Thus the activations of these cells by thrombin is a key events in hemostasis, wound healing, inflammation, atherosclerosis and restenosis of coronary artery after PTCA.
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PMID:[Regulation of the endothelial function by thrombomodulin and/or thrombin receptor]. 815 41

Based upon literature the renin-angiotensin system involvement in the pathogenesis of atherosclerosis has been discussed. Angiotensin II leads to the increased production of growth factors such as PDGF, TGF-beta, FGF and extracellular matrix proteins. There are evidences that angiotensin II stimulates expression of egr-1, c-jun, c-fos and c-myc oncogenes in vascular smooth muscle cells. Proliferation of aortic smooth muscle cells in response to the injury can be reduced by inhibitors of renin-angiotensin system what supports the hypothesis that angiotensin II can contribute to the pathogenesis of atherosclerosis.
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PMID:[Renin-angiotensin system and atherosclerosis]. 820 30

Proliferation of smooth muscle cells (SMCs) in atherosclerosis may be modulated by several growth regulatory molecules. At least two mitogens for SMCs, platelet-derived growth factor (PDGF) A-chain and heparin-binding epidermal growth factor-like growth factor (HB-EGF), can be produced by SMCs themselves and may stimulate smooth muscle proliferation in an autocrine or paracrine fashion. We examined the effects of thrombin, which may be generated at the site of vascular injury during atherogenesis, and the potent anti-inflammatory glucocorticoid, dexamethasone (DEX), on the expression of the genes encoding these two growth factors. Since both PDGF A-chain and HB-EGF have affinity for heparin, we also examined the effect of thrombin and DEX on the release of heparin binding mitogenic activity from SMCs. Treatment of SMCs with thrombin resulted in increases both in the level of the PDGF-A and HB-EGF transcripts in the cells, as well as in released heparin-binding growth factor activity. DEX inhibits the thrombin-stimulated release of mitogenic activity in a dose-dependent manner. An enzyme-linked immunoadsorbent assay showed that DEX inhibits both constitutive and thrombin-stimulated release of PDGF-AA. DEX also decreases both constitutive and thrombin-stimulated mRNA levels for PDGF A-chain and HB-EGF and destabilizes the transcripts for both growth factors. A nuclear run-on assay revealed that DEX acts, in addition, to inhibit constitutive and thrombin-stimulated transcription of the PDGF A-chain and HB-EGF genes. Thus, these findings indicate that expression of PDGF A-chain and HB-EGF may be regulated by thrombin and glucocorticoid at the transcription level. Our results are consistent with the involvement of thrombin-induced growth factor expression in neointimal SMC proliferation and suggest the possibility that intimal proliferation may be attenuated by glucocorticoids.
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PMID:Glucocorticoid inhibits thrombin-induced expression of platelet-derived growth factor A-chain and heparin-binding epidermal growth factor-like growth factor in human aortic smooth muscle cells. 822 4

The arterial wall responds to thrombosis or mechanical injury through the induction of specific gene products that increase cellular proliferation and connective tissue formation. These changes result in intimal hyperplasia that is observed in restenosis and the early phases of atherosclerosis. Transforming growth factor beta 1 (TGF-beta 1) is a secreted multi-functional protein that plays an important role in embryonal development and in repair following tissue injury. However, the function of TGF-beta 1 in vascular cell growth in vivo has not been defined. In this report, we have evaluated the role of TGF-beta 1 in the pathophysiology of intimal and medial hyperplasia by gene transfer of an expression plasmid encoding active TGF-beta 1 into porcine arteries. Expression of TGF-beta 1 in normal arteries resulted in substantial extracellular matrix production accompanied by intimal and medial hyperplasia. Increased procollagen, collagen, and proteoglycan synthesis in the neointima was demonstrated by immunohistochemistry relative to control transfected arteries. Expression of TGF-beta 1 induced a distinctly different program of gene expression and biologic response from the platelet-derived growth factor B (PDGF B) gene: procollagen synthesis induced by TGF-beta 1 was greater, and cellular proliferation was less prominent. These findings show that TGF-beta 1 differentially modulates extracellular matrix production and cellular proliferation in the arterial wall in vivo and could play a reparative role in the response to arterial injury.
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PMID:Direct transfer of transforming growth factor beta 1 gene into arteries stimulates fibrocellular hyperplasia. 824 68

For several years it has been recognised that the common denominator for many of the well known risk factors for cardiovascular disease is that they all may give rise to chronic inflammatory reactions in vascular tissues. New tools made available through rapid progress in the fields of immunology and molecular biology have made it possible to reach a better understanding of the molecular events leading to the development of atherosclerosis. These developments have resulted in a renewed interest in the role of inflammatory and immune reactions in atherogenesis. During recent years it has also become increasingly clear that the release and ability to respond to cytokines is not restricted to the cells classically included in the immune system. At least in vitro, smooth muscle cells and endothelial cells produce and respond to cytokines in a manner suggesting that they play active roles in inflammatory reactions. Several cytokines have been found to influence the growth of smooth muscle cells, suggesting a possible link between two of the major characteristics of atherosclerotic lesions: the inflammatory reaction, and the intimal proliferation of smooth muscle cells. Of particular interest is the ability of interleukin-1 and TGF beta to induce autocrine PDGF loops in smooth muscle cells. By this mechanism a transient secretion of cytokines from activated leucocytes may give rise to prolonged activation of smooth muscle cell proliferation. However, the effects of cytokines on vascular cells are very complex and it cannot be taken for granted that the inflammatory reaction generally encountered in atherosclerotic lesions only serves to promote the progress of the disease.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Cytokines and smooth muscle cells in atherosclerosis. 825 76

Low current (0.25, 3 mA) stimulation through a miniature electrode cuff encased around the carotid artery of the rat was used to induce intimal hyperplasia, an important feature of the atherosclerotic plaque and a phenomenon limiting the long term success of angioplasty. Compared to contralateral unstimulated arteries, 11-14 days of daily transmural stimulation of cuffed arteries (20 min period) significantly increased the amount of extracted DNA (diphenylamine colorimetric assay). Low current (0.25 mA) was as effective as 3 mA in producing an increase in extractable DNA. The cuff alone without applied current also stimulated an increase in DNA content but to a smaller degree than in arteries receiving current. Infusion of a calcium channel antagonist, diltiazem, at a dose which achieved therapeutic drug levels, significantly reduced the amount of electrode cuff-induced DNA content but had no effect on the increase in DNA induced by the presence of the cuff without applied current. Gene expression of PDGF-A chain, PDGF-B chain and PDGF-beta receptor (beta r) (Northern analysis of extracted carotid RNA) increased within 4 h after electrical stimulation with 3 mA. Lower current (0.25 mA) and the presence of the cuff also enhanced PDGF gene expression but with a delayed onset of several days. The pattern of gene expression for PDGF ligands and beta r during the 11-14 days of stimulation differed, but each remained above contralateral control levels. It is concluded that the continued coexpression of PDGF and one of its receptors may contribute to induced hyperplastic changes.
Atherosclerosis 1993 Apr
PMID:Electrode cuff-induced changes in DNA and PDGF gene expression in the rat carotid artery. 831 55

Distinct genes encode alpha and beta PDGF receptors which differ in their abilities to be triggered by three dimeric forms of the PDGF molecule. Each receptor is able to independently couple with mitogenic signal transduction pathways, and both are capable of inducing a readily detectable chemotactic response. The vascular smooth muscle cells which express both types of PDGF receptor are mitogenic and chemotactic for PDGFs. Moreover, the alpha receptor is the preferred receptor for platelet PDGF AB as well as the PDGF-AA isoform which is ubiquitously produced in many cells forming atherosclerotic plaques including macrophages, endothelial cells and even arterial smooth muscle cells. The availability of specific PDGF isoforms and the relative expression of each receptor gene product appear to be the major determinants of the PDGF response. An understanding of the molecular mechanisms by which the expression of PDGF and their receptors on vascular smooth muscle will give greater insights as to how these gene products are involved in atherosclerosis.
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PMID:[PDGF system in vascular smooth muscle cell proliferation]. 832 Aug 45

In lesions of atherosclerosis, various cytokines and growth factors, which are generally not expressed in the normal artery, are upregulated. Several of them including PDGF, bFGF, HB-EGF, IGF-1, IL-1 and TGF-beta and TNF play key roles in atherogenesis by stimulating chemotaxis and proliferation of vascular smooth muscle cells and production of extracellular matrix substances such as proteoglycans, collagen and elastic fibers by those cells. Endothelial cells and macrophages are also the targets as well as the sources of those cytokines and growth factors. The production of those cytokines or growth factors are regulated by molecules of each other or by themselves forming a complex cytokine network. Understanding and control of the roles of those cytokines in vascular walls will provide an insight on the mechanism of atherogenesis and contribute to the development of better ways to its prevention.
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PMID:[Roles of cytokines and growth factors in atherogenesis]. 841 65

Platelet-derived growth factor (PDGF) is a potent mitogen thought to propagate atherosclerosis and other proliferative or inflammatory diseases. Some of these diseases are ameliorated in humans by ingestion of omega-3 fatty acids. We investigated mRNA expression of both PDGF-A and PDGF-B in quiescent peripheral blood mononuclear cells from healthy male volunteers. For this, a highly sensitive, quantitative polymerase chain reaction strategy (3n-PCR) was developed. In contrast to granulocytes, both PDGF-A and PDGF-B mRNAs are expressed in mononuclear cells. This expression occurs at a remarkably constant rate. Moreover, effects of 7 g/d of a 85% omega-3 fatty acid fish oil concentrate were investigated in a 6-week controlled, randomized, observer-blind study in 14 human volunteers, 7 of whom served as controls. omega-3 Fatty acids increased in mononuclear cell phospholipids. We demonstrate for the first time that diet affects human gene regulation. Dietary omega-3 fatty acids downregulate gene expression of both PDGF-A (-66%), and PDGF-B (-70%). This may represent a novel mechanism for the antifibrotic and antiatherosclerotic action of omega-3 fatty acids.
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PMID:Dietary omega-3 fatty acids lower levels of platelet-derived growth factor mRNA in human mononuclear cells. 846 72


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