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Query: UMLS:C0004153 (atherosclerosis)
 77,401 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A total of 160 1-2 day old chickens were fed a 2% cholesterol diet for a period of 8 to 42 days and compared with an equal number of controls. Aortas were analyzed for various indexes of reactivity of connective tissue, cholesterol content and scanning electron microscopy (SEM) characteristics of the endothelial lining. Cholesterol feeding for a period up to 6 weeks resulted in doubling the level of serum cholesterol. It was, however, without effect on the activity of prolyl hydroxylase, lysyl oxidase, collagenase and collagen content in the aortic wall. As early as 3 weeks of feeding significant changes occurred in total and esterified cholesterol content. At the same time endothelial cells were characteristically contracted with several long cytoplasmic elongations and protrusions. A significant decrease of activity of the above enzymes was found in aortic tissue with increased age of the chicken. Collagen content in aortas increased with age of chickens. It is concluded that cholesterol as an atherogenic agent induces marked changes in endothelial cells and lipids of chicken aorta at earlier periods, prior to the activation of connective tissue.
Atherosclerosis 1976 Sep
PMID:Early changes in the arterial wall of chickens fed a cholesterol diet. 0 48

A number of soluble proteins contained in human aortic intimal tissue was extracted into buffered saline (pH 7.4) and identified and quantitated by immunoelectrophoresis and immunodiffusion. The proteins included IgA, IgG, IgM, B1C (C3), alpha 1-antitrypsin, alpha 2-macroglobulin, fibrinogen, albumin, LDL, HDL, alpha 1-acid glycoprotein, beta 2-glycoprotein, transferrin and ceruloplasmin. The concentration of soluble proteins was significantly higher in the atherosclerotic intima than in the normal intima. The diseased intima also contained a small amount of tissue-bound IgG, IgA and B1C which was extractable with citrate buffer at pH 3.2. The vascular band IgG, and B1C were shown by enzymatic and immunohistochemical studies to be closely associated with the collagenous tissue of the plaque. The Ig contained in the atherosclerotic plaque may be derived in part from the biosynthesis of Ig by the artery, since the incorporation of 14C-labeled leucine into IgG by the atheromatous plaque was demonstrable by radioimmunoelectrophoresis. In contrast to the diseased artery, the normal artery did not synthesize IgG and did not contain vascular bound IgG or complement. However, the normal artery was capable of fixing IgG and B1C eluted from the diseased artery. The present studies suggested that the IgG contained and synthesized by the plaque might represent an immune response to an endogenous or exogenous antigen closely associated with plaque collagen. IgG and B1C either alone or in the form of an immune complex also may play an important role in phagocytosis in the plaque and thereby influence the course of atherosclerosis. The proteolytic inhibitors, alpha 1-antitrypsin and alpha 2-macroglobulin, found in relatively high concentrations in the plaque, could enhance fibrosis of the lesion because of thier known inhibitory effects on collagenase and elastase.
Atherosclerosis 1979 Dec
PMID:Soluble proteins in the human atherosclerotic plaque. With spectral reference to immunoglobulins, C3-complement component, alpha 1-antitrypsin and alpha 2-macroglobulin. 9 93

Endothelial cells from porcine aorta and inferior vena cava have been harvested, using trypsin, EDTA or collagenase, and grown in tissue culture. Growth-behaviour, cytology, scanning and electronmicroscopy findings are reported. It is hoped that this technique will prove useful in the investigation of atherosclerosis.
Atherosclerosis
PMID:The porcine endothelial cell in tissue culture. 16 26

Increased aortic and liver prolyl hydroxylase activity has been suggested as an early biochemical indicator of the fibrotic changes which occur in rabbits with injury induced arteriosclerosis. Daily administration of epinephrine (0.025-0.050 mg/kg, i.v.) and thyroxine (0.050 mg/kg, i.p.) to rabbits for 3 weeks produced aortic fibrous plaques with a 4-fold increase in aortic prolyl hydroxylase and also a 5-fold increase in liver prolyl hydroxylase. Histopathologically, the livers of these rabbits show subcapsular areas of necrosis. When total prolyl hydroxylase related antigen was measured. the increase in liver prolyl hydroxylase activity accounted for only a small portion of the total prolyl hydroxylase antigen. However, in the aorta a majority of the increase in antigen is due to the increased amount of enzyme. DNA content per aorta was unchanged and RNA content increased in the aortic tissue of the arteriosclerotic rabbits. However DNA and RNA levels increased 60% in the livers of arteriosclerotic rabbits. In vitro incorporation of radioactively labeled proline into collagenase digestable protein was at least 2-fold greater in aorta and liver minces from arteriosclerotic rabbits. Michaelis--Menten kinetic parameters were obtained for the liver prolyl hydroxylase purified by affinity chromatography from arteriosclerotic rabbits. The Km for the enzyme from treated animals was not significantly different from control. However, the Vmax of the enzyme purified from diseased liver was 4-fold greater when compared to controls.
Atherosclerosis 1976 Sep
PMID:Increased collagen synthesis and the kinetic characteristics of prolyl hydroxylase in tissues of rabbits with experimental arteriosclerosis. 18

A large amount of plasma low density lipoprotein is present in human aortic intima, and this can be removed and measured by electrophoresis directly from the minced tissue into an antibody-containing gel. We now find that, in addition to this electrophoretically mobile lipoprotein, there is an immobilized lipoprotein fraction than can be released from lesions by incubation of the tissue sample with plasmin or other proteolytic enzymes after the mobile lipoprotein has been removed. The concentration of immobilized lipoprotein is highly correlated with the concentration of the residual cholesterol (not mobile on electrophoresis) that has accumulated in the tissue (r = 0.702; P less than 0.001). Thus, in normal intima and early gelatinous lesions it is about 15% of the concentration of mobile lipoprotein, whereas in the atheroma lipid layers of fibrous or gelatinous plaques it may be 2 or 3 times greater than the concentration of mobile lipoprotein. This suggests that immobilization of plasma lipoprotein is an intermediate step in the irreversible deposition of extracellular cholesterol in atherosclerotic lesions. Incubation with plasmin allowed maximum release of lipoprotein: plasmin = crude collagenase greater than trypsin greater than "pure" collagenase greater than chondroitinase ABC in order of their relative effectiveness. The concentration of immobilized lipoprotein was significantly correlated (r = 0.793; P less than 0.001) with the concentration in the tissue of fibrin or other insoluble derivatives of fibrinogen ("fibrin"). In aliquots of lesions incubated with varying amounts of plasmin for varying times there was a constant relation between release of lipoprotein and release of fibrin-degradation products. Together, these findings suggest that the lipoprotein is associated with insoluble "fibrin". This appears to be of considerable clinical interest, suggesting a synergism between lipoprotein and fibrinogen in the accumulation of lipid in lesions.
Atherosclerosis 1976 Oct
PMID:The release of an immobilized lipoprotein fraction from atherosclerotic lesions by incubation with plasmin. 18 79

Incorporation of 125I-labeled cholesterol ester rich lipoproteins from cholesterol fed rabbits into normal rabbit aorta in vitro was inhibited by heparin, lecithin, and collagenase and by succinylation of the lipoprotein. Aortic uptake of lipoprotein was increased by neuraminidase, proteases, lipase, and beta-glucuronidase. These results suggest that it may be possible to control atherogenesis by controlling the interaction of atherogenic lipoproteins with their arterial receptor.
Atherosclerosis
PMID:Control of the interaction of cholesterol ester-rich lipoproteins with arterial receptors. 18 30

The interaction of lipoproteins and arterial connective tissue macromolecules was studied using human atherosclerotic plaque tissues. After extraction with 0.15 M NaCl, the tissues were repeatedly digested with collagenase followed by elastase. The collagenase-solubilized lipoprotein--GAG complexes were isolated by gel-filtration and ultracentrifugation and analyzed for lipids, GAG and protein. While extraction by 0.15 M NaCl released only about 13% of the total cholesterol from the tissues, subsequent digestions by collagenase and elastase yielded 60% and 17% cholesterol, respectively. Both 0.15 M NaCl and collagenase treatment released equal amounts of GAG and accounted for 84% of the total GAG. Immunologically, lipoproteins resembled serum apoB-containing lipoproteins. Bio-Gel A-50m column chromatography of collagenase-extracted materials gave a single peak which contained lipoproteins of 1.006 and 1.063 floating densities, GAG and hydroxyproline. Hyaluronic acid (HA) and chondroitin 6-sulfate were identified; HA was the major GAG. Although the precise nature of the interaction of arterial connective tissue components with lipoproteins is not completely understood, isolation of such complexes indicates the importance of these macromolecules in sequestration of lipoproteins.
Atherosclerosis 1979 Oct
PMID:Collagenase-solubilized lipoprotein--glycosaminoglycan complexes of human aortic fibrous plaque lesions. 22 69

Elastin was extracted from human aortic plaque and adjacent grossly normal intima by the following methods: (1) 0.1 N NaOH at 100 degrees C, (2) hot NaOH and 0.2 M EDTA, (3) 5 M guanidine--HCl and collagenase, (4) guanidine--collagenase and dithioerythritol--urea--sodium dodecyl sulfate, (5) guanidine--collagenase and EDTA, (6) 10% NaCl and collagenase, and (7) NaCl--collagenase and EDTA. All elastin samples contained small amounts of carbohydrate and hydroxyproline. The lipid content of non-plaque intimal elastin samples was small (2--3%), whereas it increased to 4--6% in plaque intima. The lipid composition of elastin preparations varied significantly with the extraction procedure. Elastin from plaque intima contained significantly more cholesterol (50--60%) and less triglyceride and phospholipid than elastin of non-plaque intima (30--50% cholesterol). The contents of free and esterified cholesterol were comparable in all preparations. The main phospholipid in all samples was sphingomyelin, which comprised between 50 and 80% of the total phospholipid. Compared with NaOH-purified elastin, the other elastin samples were characterized by an increased phosphatidyl--choline content, while they all contained an almost equal amount of phosphatidylethanolamine. In elastin samples from plaque intima, the polar amino acids were increased, whereas cross-linking amino acids were decreased. The polarity and hydroxyproline content of elastin samples were slightly decreased after treatment with EDTA or dithioerythritol--urea--sodium dodecyl sulfate.
Atherosclerosis 1979 May
PMID:Elastin--lipid interaction action in the arterial wall. Part 1. Extraction of elastin from human aortic intima. 46 28

Aortic tissues consisting of all three tunics were removed from normal adult rabbits and cultured in a semisynthetic gelosed medium supplemented by 10% serum obtained either from normal or hypercholesterolemic rabbits. Fibrillar cross-striated aggregates appeared with a high frequency (50%) in the extracellular space of explants cultured from four to eight days in medium supplemented by serum from hypercholesterolemic rabbits, but did not appear in explants cultured in serum from control animals (3%). The electron-dense segment was ruthenium red positive and digested by testicular hyaluronidase. The electron-lucent segment, composed of ruthenium red negative thin filaments, was not modified after hyaluronidase treatment but was strongly digested after collagenase treatment. It is believed that this material was fibrous long spacing collagen synthetized under culture conditions, as shown after tritiated proline incorporation.
Atherosclerosis 1977 Sep
PMID:Fibrous long spacing collagen in aortic explants of normal rabbit cultured in hypercholesterolemic serum. 91 68

Foam cells were isolated from atherosclerotic aortas of rabbits following their intima incubation with collagenase and elastase. The viability of the cells, their incidence and nativity were supported histochemically and electron-microscopically. The interaction of the foam cells with lipoproteins was studied in vitro with perfusions of isolated atherosclerotic aortas of rabbits during 6 hours with a medium containing beta- and pre-beta-lipoproteins labelled with I125 or simultaneously with I125 and C14-cholesterol. It was found that after the perfusion the foam cells contain a much higher proportion of radioactivity of the total lipids, cholesterol and cholesterol esters, to that of the proteins, than the perfusate. The foam cells must selectively "capture" the lipids from the lipoprotein particles. The proportion "free cholesterol/cholesterol esters" (according to the radioactivity) proved to be much higher in the foam cells than in the perfusate. The possible mechanisms of the participation of the foam cells in the metabolism of lipoproteins and in the pathogenesis of atherosclerosis are discussed.
 ...
PMID:[Role of foam cells in lipoprotein transformation within the vascular wall]. 96 40


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