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Query: UMLS:C0004153 (
atherosclerosis
)
77,401
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Three major factors are involved in the development of atherosclerotic disease: 1) increased vasoconstrictor responses of the blood vessel wall; 2) increased platelet-vessel wall interaction and activation of coagulation factors; and 3) proliferative responses of vascular smooth muscle. Vascular smooth muscle cells proliferate in the media, migrate to the intima, and again proliferate on reaching the subendothelial space. In healthy blood vessels, these events do not occur due to the absence of growth promoters and/or the presence of growth inhibitors. Endothelial cells release growth inhibitors such as heparin sulphates and transforming growth factor beta 1 (TGF
beta 1
) as well as nitric oxide (NO) and prostacyclin. In rat vascular smooth muscle, NO inhibits proliferation and migration, particularly that induced by angiotensin II. Under certain conditions, the endothelium also releases growth promoters, such as basic fibroblast growth factor, platelet-derived growth factor (PDGF) and endothelin 1, which also can facilitate proliferative responses. Another important source of growth factors are adhering platelets which release PDGF and TGF
beta 1
(albeit in its inactive form), and monocytes which are capable of releasing various growth factors. Furthermore, mechanical forces are important in the development of
atherosclerosis
, including transmural pressure and, in particular, pulsatile stretch. Indeed, heart rate is an independent risk factor for coronary artery disease and pulsatile stretch in vitro causes proliferation of human coronary as well as saphenous vein smooth muscle cells. The intracellular mediators involved in these proliferative responses are tyrosine kinase and S6 kinase. Calcium antagonists reduce only PDGF-induced proliferation whereas that due to mechanical forces is unaffected.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Endothelium in the control of vascular tone and growth: role of local mediators and mechanical forces. 820 93
The phenotypic transition of smooth muscle cells (SMC) from a contractile to a synthetic state appears to be an early event in the pathogenesis of
atherosclerosis
. We examined the effects of extracellular matrix components on the phenotypic modulation of rabbit arterial SMC in primary culture by flow cytometry. The results demonstrate that freshly isolated SMC attached, spread, and started to proliferate on type I collagen as well as on fibronectin. Moreover, type I collagen was as efficient as fibronectin in promoting the transition of the cells into the synthetic phenotype without exogenous mitogens. However, unlike on fibronectin, the synthetic peptide GRGDSP (Gly-Arg-Gly-Asp-Ser-Pro) and the peptide KDGEA (Lys-Asp-Gly-Glu-Ala), which contains the recognition sequence for alpha 2
beta 1
integrin in type I collagen, interfered little with the attachment, spreading, and phenotypic modulation of the cells on type I collagen. On the other hand, the phenotypic modulation of the cells was counteracted by the anti-
beta 1
integrin antibody. These findings indicate that type I collagen promotes the phenotypic transition of the rabbit arterial SMC by interacting with a cell surface receptor (
beta 1
integrin family) for a cell-binding sequence without RGD and DGEA. In contrast, elastin, a major constituent of the media, suppressed the cell attachment and spreading and maintained the cells in the contractile phenotype as laminin. These results suggest diverse roles of type I collagen and elastin as well as of fibronectin and laminin in the control of the differentiated properties of arterial SMC.
...
PMID:Type I collagen promotes modulation of cultured rabbit arterial smooth muscle cells from a contractile to a synthetic phenotype. 841 90
The effects of platelet-derived growth factor (PDGF), transforming growth factor-beta 1 (TGF-beta 1) and interleukin-1 (IL-1) on collagen synthesis of cultured human arterial smooth muscle cells in a confluent state were investigated. Synthetic activity of collagenous protein was determined with [3H]-proline uptake, and subsequent analysis of collagen types by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) followed by fluorography. Although PDGF (0.5 U/mL and 5.0 U/mL) enhanced total collagen synthesis per dish, it suppressed total collagen synthesis per DNA (DNA content in a dish). TGF-beta 1 (10 pmol/L and 100 pmol/L) enhanced total collagen synthesis both per dish and per DNA. IL-1 (0.1 U/mL and 1.0 U/mL) suppressed total collagen synthesis both per dish and per DNA. A fluorogram revealed that human arterial smooth muscle cells synthesize types I, III, IV and V collagen. Densitometric analysis showed PDGF suppressed the proportion of type IV collagen and increased that of type V collagen. TGF-beta 1 increased the proportions of types IV and V collagen. IL-1 elicited un- remarkable change in the proportion of collagen types. These results suggest that, in the event of human
atherosclerosis
, TGS-
beta 1
is most effective in enhancing collagen synthesis, and PDGF modulates collagen metabolism by stimulating a cell division of smooth muscle cells with a resultant increase of collagenous protein, especially of type V collagen.
...
PMID:Collagen synthesis of human arterial smooth muscle cells: effects of platelet-derived growth factor, transforming growth factor-beta 1 and interleukin-1. 849 67
Carvedilol is a vasodilating beta-blocker currently marketed for the treatment of mild to moderate hypertension and application is being filed to the FDA for treatment of congestive heart failure. Carvedilol reduces peripheral vascular resistance by blocking arterial alpha 1-adrenoceptors, thereby producing vasodilation, while preventing reflex tachycardia by blocking cardiac
beta 1
- and beta 2-adrenoceptors. In addition to the safety and efficacy of carvedilol as an antihypertensive agent, experimental studies indicate that carvedilol also provides significant cardioprotection in animal models of acute myocardial infarction as well as protection against the vascular remodelling that occurs following injury of the vasculature. Recent pharmacological studies have uncovered several novel properties of carvedilol which may function to protect the heart and vasculature from chronic pathological processes, such as ischaemia,
atherosclerosis
and the remodelling that occurs in the heart and blood vessels as a consequence of pressure overload, injury or shear stress. Specifically, carvedilol, likely as a result of the carbazol moiety, is a potent anti-oxidant. In physicochemical, biochemical and cellular assays carvedilol and several of its metabolites inhibit lipid peroxidation, scavenge oxygen free radicals, inhibit the formation of reactive oxygen radicals and prevent the depletion of endogenous antioxidants, such as vitamin E and glutathione. Moreover, carvedilol blocks the oxidation of low-density lipoproteins (LDL), and thereby prevents the formation of oxidized-LDL which is believed to stimulate foam cell formation and augment the development of atherosclerotic plaque. The ability of carvedilol to prevent the formation of oxidized LDL, in addition to the general anti-oxidant properties of the compound, results in the protection of the endothelium from oxygen free radical injury, and thereby prevents the subsequent events triggered by endothelial damage. Recently, carvedilol has also been shown to inhibit vascular smooth muscle cell proliferation and migration. Because carvedilol can inhibit vascular smooth muscle cell proliferation induced by a wide variety of mitogens (e.g. growth factors, angiotensin II, endothelin, thrombin), it is likely that the site of inhibition occurs at some point beyond the specific mitogen receptors, possibly at a distal common pathway that affects the smooth muscle cell cycle. These unique activities of carvedilol have also been confirmed in vivo in a rat model of neointimal formation following vascular injury by balloon angioplasty, where vascular smooth muscle cell migration and proliferation are the key processes involved in the formation of neointima leading to vascular stenosis. In this model, carvedilol suppressed neointimal growth to a remarkable extent ( > 85% inhibition of neointimal formation) at a dose that is similar to the antihypertensive dose used clinically in hypertensive patients. Taken together, these unique multiple actions of carvedilol provide not only for adequate control of elevated blood pressure, but may also provide for protection of the heart and vasculature from secondary damage due to hypertension itself, as well as from other causes, such as ischaemia, pressure overload, shear stress, vascular injury and
atherosclerosis
.
...
PMID:Carvedilol, a novel vasodilating beta-blocker with the potential for cardiovascular organ protection. 873 68
The ability of leukocytes to leave the blood-stream and migrate into tissues is a critical feature of the immune system, essential in eliminating infectious pathogens and allowing leukocyte accumulation at sites of injury, infection or inflammation. Lymphocytes continuously recirculate between tissues, lymphoid organs and blood, whereas neutrophils or monocytes lack this capacity. Migration of various leukocyte subpopulations into tissues is regulated by specific combinations of adhesion receptors and chemoattractants which direct them into tissues. Selectins initiate leukocyte attachment along vascular endothelium by mediating leukocyte rolling along inflamed endothelium, whereas CD11/CD18 (alpha L, M, X/beta 2) integrins have a more important role in subsequent steps of leukocyte migration into tissues. alpha 4/
beta 1
or alpha 4/beta 7 integrins play a role in mediating lymphocyte rolling and firm adhesion to vascular wall. Leukocyte migration is an important mechanism in the pathogenesis of inflammatory diseases, the regulation of hematopoiesis and hemostasis. This reaction is also involved in the pathogenesis of
atherosclerosis
, reperfusion injuries and malignant cell metastasis. Leukocyte migration inhibitors may have therapeutic potential against inflammation and associated diseases.
...
PMID:[Regulation of leukocyte migration by adhesion molecules]. 899 20
The transforming growth factor beta 1 (TGF
beta 1
) signalling pathway is important in embryogenesis and has been implicated in hereditary haemorrhagic telangiectasia (HHT),
atherosclerosis
, tumorigenesis and immunomodulation. Therefore, identification of factors which modulate TGF
beta 1
bioactivity in vivo is important. On a mixed genetic background, approximately 50% Tgfb1-/- conceptuses die midgestation from defective yolk sac vasculogenesis. The other half are developmentally normal but die three weeks postpartum. Intriguingly, the vascular defects of Tgfb1-/- mice share histological similarities to lesions seen in HHT patients. It has been suggested that dichotomy in Tgfb1-/- lethal phenotypes is due to maternal TGF
beta 1
rescue of some, but not all, Tgfb1-/- embryos12. Here we show that the Tgfb1-/- phenotype depends on the genetic background of the conceptus. In NIH/Ola, C57BL/6J/Ola and F1 conceptuses, Tgfb1-/- lethality can be categorized into three developmental classes. A major codominant modifier gene of embryo lethality was mapped to proximal mouse chromosome 5, using a genome scan for non-mendelian distribution of alleles in Tgfb1-/- neonatal animals which survive prenatal lethality. This gene accounts for around three quarters of the genetic effect between mouse strains and can, in part, explain the distribution of the three lethal phenotypes. This approach, using neonatal DNA samples, is generally applicable to identification of loci that influence the effect of early embryonic lethal mutations, thus furthering knowledge of genetic interactions that occur during early mammalian development in vivo.
...
PMID:Mapping of a major genetic modifier of embryonic lethality in TGF beta 1 knockout mice. 902 Aug 52
We have measured the levels of glycosphingolipids and the activity of glycosphingolipid glycosyltransferases in human aortic intima and media from patients who died of
atherosclerosis
. The effects of lactosylceramide (LacCer) and glucosylceramide (GlcCer) from plaque intima on smooth muscle cell proliferation were assessed. When the GlcCer data was expressed as (micrograms GlcCer/mg cholesterol and/mg total phospholipid, a 28-fold and 7-fold increase in plaque intima compared to normal intima was observed. Similarly, the level of LacCer was elevated 5-fold and 4-fold, respectively, compared to unaffected intima. The activity of UDP-GlcCer: ceramide
beta 1
-->4 glucosyltransferase (GlcT-1) was similar in unaffected tissue, fatty streaks, and plaques. However, the activity of UDP-galactose: GlcCer,
beta 1
-->4 galactosyltransferase (GalT-2) activity was moderately higher in plaque than in unaffected tissue. LacCer, but not GlcCer derived from plaque intima exerted a approximately 2.8-fold increase in the proliferation of human aortic smooth muscle cells grown in tissue culture compared to control presumably due to a marked increase in LacCer molecular species containing C16:0, C22:1, and C24:0 fatty acids in plaque intima compared to control. In sum, our findings provide an interesting and novel pathogenic mechanism of lactosylceramide mediated plaque formation via stimulation of aortic smooth muscle cell proliferation.
...
PMID:Accumulation of glycosphingolipids in human atherosclerotic plaque and unaffected aorta tissues. 906 65
Atherosclerosis
is characterized as a chronic inflammatory-fibroproliferative disease of the vessel wall. The attachment of monocytes and T-lymphocytes to the injured endothelium followed by their migration into the intima is one of the first and most crucial steps in lesion development. The co-localization of CD4+ T-cells and macrophages in the lesion, the abundant expression of HLA Class II molecules and the co-stimulatory molecule CD40 and its ligand (CD40L) indicate a contribution of cell-mediated immunity to atherogenesis. Transgenic mouse models revealed that dependent on the model T- and B-cells may promote lesion progression, monocytes and macrophages are in contrast essential for the development of atherosclerotic lesions. Apart from the local process in the vessel wall, systemic signs of an inflammatory reaction are also associated with lesion development. Thus plasma levels of C-reactive protein and fibrinogen and the white blood cell count are positively correlated to the risk of cardiovascular disease. Recently, an inflammatory phenotype of circulating peripheral blood monocytes could be demonstrated as a specific cellular correlate to lipid and lipoprotein risk factors. Thus the pool size of LPS receptor (CD14)dim and Fc gamma IIIa receptor (CD16a)+ monocytes positively correlates to plasma cholesterol levels, to triglycerides levels and to the apolipoprotein E4 (apo E4) phenotype in contrast to a negative correlation to the high density lipoprotein (HDL) cholesterol concentration. This CD14dim CD16a+ monocytes are further characterized by a high expression of
beta 1
- and beta 2-integrins, suggesting a higher capacity for attachment at sites of inflammation. A proinflammatory cytokine pattern and an expansion of these cells in other inflammatory diseases are indicating that these cells promote the inflammatory process during atherogenesis. Surface expression of the activation antigen CD45RA on monocytes in correlation to plasma LDL cholesterol and Lp(a) levels further indicates an inflammatory reaction. Regarding the potential mechanisms of the phenotypic changes of peripheral blood monocytes, in a serum free in vitro differentiation model supplemented with M-CSF monocytes from probands which are homozygous for apo E4 showed a significantly higher increase of CD16a expression compared to apo E3/E3 cells indicating that a genetic polymorphism of a single apolipoprotein gene locus may affect monocyte differentiation. The further characterization of the cellular immunology of monocytes and T-lymphocytes in lesion development will provide new specific diagnostic and therapeutic targets in atherogenesis.
...
PMID:T-lymphocytes and monocytes in atherogenesis. 964 98
Stimulating cardiac
beta 1
-adrenoceptors with oxyfedrine causes dilatation of coronary vessels and positive inotropic effects on the myocardium.
beta 1
-adrenergic agonists increase coronary blood flow in nonstenotic and stenotic vessels. The main indication for the use of the phosphodiesterase inhibitors pamrinone, mirinone, enoximone and piroximone is acute treatment of severe congestive heart failure. Theophylline is indicated for the treatment of asthma, chronic obstructive pulmonary disease, apnea in preterm infants ans sleep apnea syndrome. Severe arterial occlusive disease associated with
atherosclerosis
can be beneficially affected by elcosanoids. These drugs must be administered parenterally and have a half-life of only a few minutes. Sublingual or buccal preparations of nitrates are the only prompt method (within 1 or 2 min) of terminating anginal pain, except for biting nifedipine capsules. The short half-life (about 2.5 min) of nitroglycerin (glyceryl trinitrate) makes long term therapy impossible. Tolerance is a problem encountered with longer-acting nitric oxide donors. Knowledge of the pharmacokinetic properties of vasodilating drugs can prevent a too sudden and severe blood pressure decrease in patients with chronic hypertension. In considering the administration of a second dose, or another drug, the time necessary for the initially administered drug to reach maximal efficacy should be taken into account. In hypertensive emergencies urapidil, sodium nitroprusside, nitroglycerin, hydralazine and phentolamine are the drugs of choice, with the addition of beta-blockers during catecholamine crisis or dissecting aortic aneurysm. Childhood hypertension is most often treated with angiotensin-converting enzyme (ACE) inhibitors or calcium antagonists, primarily nifedipine. Because of the teratogenic risk involved with ACE inhibitors, extreme caution must be exercised when prescribing for adolescent females. The propagation of health benefits to breast-fed infants, combined with more women delaying pregnancy until their fourth decade, has entailed an increase in the need for hypertension management during lactation. Low dose hydrochlorothiazide, propranolol, nifedipine and enalapril or captopril do not pose enough of a risk of preclude breastfeeding in this group. The most frequently used antihypertensive agents during pregnancy are methyldopa, labetalol and calcium channel antagonists. Methyldopa and beta-blockers are the drugs of choice for treating mild to moderate hypertension. Prazosin and hydralazine are used to treat moderate to severe hypertension and hydralazine, urapidil or labetalol are used to treat hypertensive emergencies. The use of overly aggressive antihypertensive therapy during pregnancy should be avoided so that adequate uteroplacental blood flow is maintained. Methyldopa is the only drug accepted for use during the first trimester of pregnancy.
...
PMID:Clinical pharmacokinetics of vasodilators. Part II. 967 32
One of the most important events in the reaction to all forms of injury is adhesion of leukocytes to endothelium, a prelude to their emigration into tissues. This process is central to inflammation,
atherosclerosis
, and immune reactions. Endothelial-leukocyte adhesion is governed largely by the interaction of complementary adhesion molecules on endothelia and leukocytes. The synthesis, surface expression, and avidity of these molecules, are regulated by chemical mediators, particularly chemokines. The most important adhesion molecule pairs are the selectins (E, L and P), the immunoglobulins ICAM-1 and VCAM-1, and the beta 2 and
beta 1
integrins (e.g., LFA-1 and VLA-4). In vivo studies in experimental animals and humans have confirmed a role for these molecules in a number of pathological processes, including transplant rejection, septic shock,
atherosclerosis
, late phase hypersensitivity reactions, immunologically-mediated lung and kidney disease, and reperfusion injury. Besides their importance in understanding pathogenesis, work on adhesion molecules has direct clinical implications in diagnosis and therapy. Current studies suggest that the expression of these adhesion molecules may be a useful marker for active inflammation under certain conditions, and that abrogation of endothelial adhesion by interfering with such molecules may inhibit tissue injury. Mice genetically deficient in adhesion molecules (knock out) have been particularly useful in the study of the role of these molecules in vivo. This lecture will first summarize the state-of the-art on the structure, localization, and distribution of the major adhesion molecules, examine their roles in vivo, in humans and knock-out mice, and point to possible use of the information derived from these studies in diagnosis and therapy.
...
PMID:Endothelial adhesion molecules in health and disease. 976 11
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