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

Arterial elastin appears to be a proteinlipid complex with the lipid component being bound to elastin peptide groups. In atherosclerotic lesions the lipid content of elastin increases progressively with increasing severity of atherosclerosis. The increases in the lipid content of plaque elastin are mainly due to large increases in cholesterol with about 80% of the cholesterol being cholesterol ester. This deposition of cholesterol in elastin accounts for a substantial part of the total cholesterol accumulation in atherosclerotic lesions of all stages. The present in vitro study suggests that the mechanism involved in the deposition of lipids in arterial elastin may be an interaction of the elastin protein with serum or arterial low density or very low density lipoproteins (LDL and VLDL) resulting in a transfer of lipids, but not of lipoprotein protein to the elastin. No significant lipid transfer occurred from the high density lipoproteins or chylomicrons. The amount of lipid taken up by plaque elastin was strikingly higher than by normal elastin and consisted mainly of cholesterol with over 80% of the cholesterol being cholesterol ester. The precondition for the lipid accumulation in plaque elastin appeared to be an altered amino acid composition of the elastin protein consisting of an increase in polar amino acids and a reduction in cross-linking amino acids. Subsequent treatment of lipoprotein-incubated arterial elastin with hot alkali and apolipoproteins did not reverse the binding of lipoprotein lipid to diseased elastin.
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PMID:The interaction of serum and arterial lipoproteins with elastin of the arterial intima and its role in the lipid accumulation in atherosclerotic plaques. 434 5

Elastin preparations from intimal layers and the media of normal and atherosclerotic human aortae were analyzed for protein and lipid content. In atherosclerotic aortae, elastin from plaques was compared with elastin from adjacent normal appearing areas of the same aorta. Arterial elastin purified by alkaline extraction appeared to be a protein-lipid complex containing free and ester cholesterol, phospholipids, and triglycerides. The lipid component of normal arterial elastin was small (1-2%). With increasing severity of atherosclerosis, there was a progressive accumulation of lipid in intimal elastin from plaques, reaching a mean lipid content of 37% in severe plaques. The increase in the lipid content of plaque elastic preparations was mainly due to large increases in cholesterol, over 80% of which was cholesteryl ester. This deposition of cholesterol in plaque elastin accounted for 20-34% of the total cholesterol content of the plaque. The increased lipid deposition in plaque elastin was associated with alterations in the amino acid composition of plaque elastin. In elastin from plaque intima, the following polar amino acids were increased significantly: aspartic acid, threonine, serine, glutamic acid, lysine, histidine, and arginine; whereas, cross-linking amino acids: desmosine, isodesmosine, and lysinonorleucine were decreased significantly. The amino acid and lipid composition of elastin from normal appearing aortic areas was comparable to that of normal arterial elastin except for intimal elastin directly adjacent to and medial elastin directly below the most severe plaques.The data indicate that the focal lipid deposition in early atherosclerotic plaques is due to a large extent to lipid accumulations in altered elastin protein of localized intimal areas. Continued lipid deposition in altered elastin appears to contribute substantially to the progressive lipid accumulation in the plaque. The study suggests that elastin of intimal elastic membranes may play an important role in the pathogenesis and progression of atherosclerosis.
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PMID:The protein and lipid composition of arterial elastin and its relationship to lipid accumulation in the atherosclerotic plaque. 509 73

Male Sprague-Dawley rats were treated with D-penicillamine (D-pen) in doses of 100, 250 or 500 mg/kg per day for 10, 32, 42 or 70 days. In addition animals were examined 28 days after withdrawal from 42 day's treatment with D-pen at 100 or 500 mg/kg per day. Pair-fed rats served as controls. The changes in aortic collagen, glycosaminoglycans (GAGs), DNA and RNA were studied. D-Pen had a dose- and time-related solubilizing effect on aortic collagen, which regained normal resistance to extraction within 28 days after cessation of the treatment. In contrast, D-pen caused a progressive accumulation of hydroxyproline (Hyp) in the aortic wall during and after treatment, probably mediated by an increased number of matrix synthesizing cells, as judged by augmentation of the DNA content in the presence of unaltered Hyp/DNA and RNA/DNA ratios. The relative amount of type III collagen was increased after 500 mg/kg per day D-pen for 10 and 42 days. High doses of D-pen increased the percentage of water in the aortic wall and reduced the ratio of Hyp to total tissue protein, suggesting an increased content of water-binding substances. This was confirmed by GAG accumulation. Hyaluronic acid (HA) and chondroitin 4,6-sulphate (CHS) were predominant after 32 and 42 days, whereas CHS, heparan sulphate (HS) and dermatan sulphate (DS) prevailed after 70 days of treatment. These observations suggest that processes of repair and regeneration are elicited secondary to the inhibitory effect of D-pen on aortic collagen and elastin crosslinking. Hypertrophy of the vessel wall may imply an increased rigidity, resulting in further increase of the susceptibility to haemodynamic injury.
Atherosclerosis 1982 Oct
PMID:D-penicillamine-induced angiopathy in rats. Changes in aortic collagen, glycosaminoglycans, DNA and RNA in rats treated with D-penicillamine. 618 62

The NaOH sonication digestion technique permits rapid isolation and exposure of intact networks of elastic fibers in vascular tissue for 3-dimensional observation with the SEM. The configuration of the network of elastic fibers within the vascular wall of large elastic arteries (aorta) is generally agreed to be a flexible framework through which smooth muscle cells and collagenous fibers are interwoven. However, the configuration of elastic fiber networks in muscular arteries, medium sized veins and smaller vessels remains unknown. When the lengthy standard biochemical elastin purification techniques were applied to vessels containing lesser amounts of elastic tissue and finer elastic fibers, the vessels were completely digested. In contrast, the digestion and sonication technique isolated and exposed intact networks of delicate elastic fibers in blood vessels which do not contain large amounts of elastic tissue. Unfixed vessels were cut into short segments, placed in 0.5 N NaOH and sonicated for 20-40 min. The specimens were rinsed in deionized distilled H2O, then autoclaved for 30 min. The tissue was rinsed a second time, fixed and processed routinely for SEM. Elastic stains and enzymatic digestion with chromatographically purified elastase and collagenase confirmed that the digestion and sonication technique produced clean, isolated networks of elastic fibers. Knowledge of the configuration of the networks of elastic fibers in different vessels enhances understanding of distensibility characteristics of individual vessels and serves as a baseline for studying alterations in the elastic framework which occur during aging and disease processes such as atherosclerosis, arterial hypertension and aneurysms.
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PMID:A rapid digestive technique to expose networks of vascular elastic fibers for SEM observation. 620 43

Destruction (elastolysis) of the internal elastic lamina is frequently observed near early atherosclerotic plaques. Elastolysis and plaque formation are also found together in the temporal arteritis/polymyalgia rheumatica syndrome. Could it be that atherosclerosis and the syndrome are more closely akin than usually thought, with elastolysis acting as the pathogenetic link between them? A kinship of this nature is in accord with the growing recognition that elastin-related autoimmunity prevails in both these forms of vascular disease. A case can also be made out for the belief that the autoimmune reactions in internal vessels may be provoked by events in the integument where a slow but ultimately massive turnover of dermal and vascular elastic tissue takes place under the harmful influence of solar and other forms of actinic radiation.
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PMID:Destruction of elastic tissue (elastolysis) as a link between atherosclerosis and the temporal arteritis/polymyalgia rheumatica syndrome. Observations on an actinic factor in vascular disease. 636 8

Hypertension is a major risk factor for clinically significant atherosclerotic vascular disease in Western Society, although the link between these conditions remains very poorly understood. Recent studies which are reviewed here have demonstrated that major arterial intimal and medial abnormalities occur as a result of hypertension. These include functional changes in endothelial permeability as well as alterations in the endothelial cells themselves with an increase in their turnover and number and distinct changes in morphology. However, endothelial cell loss leading to denudation of the arterial intimal surface appears to be relatively uncommon. Intimal and medial thickening are consistent features of hypertension and result from increases in both cellular and extracellular components. The cells accumulating in the subendothelial space appear to be of both blood-borne and medial origins, although their complete characterization has not been performed as yet. The adherence of blood cells to the endothelial surface appears to be promoted by the presence of hypertension along with their increased entry into the intima through endothelial cell junctions. Medial thickening with hypertension is attributable primarily to increased smooth muscle cell mass, although enhanced deposition of collagen and elastin plays a contributory role. Recent data would indicate that smooth muscle cell hypertrophy rather than hyperplasia is primarily responsible for the greater smooth muscle mass with hypertension. Although elevated DNA content of hypertensive arteries has been demonstrated, such changes may be secondary to a marked increase in cells showing nuclear polyploidy. Prolonged normalization of blood pressure in hypertensive animals can produce considerable regression of arterial changes toward the control state. The changes appear more marked with respect to the cellular rather than the extracellular abnormalities induced by hypertension. In man, little is known about the effects of antihypertensive therapy on the vasculature itself, although clinical complications related to both hemorrhagic or thrombotic strokes are clearly reduced by blood pressure reduction. On the other hand, the influence of treatment on the atherosclerotic process or on the course of coronary artery disease and its complications is not currently understood. The accelerating effect of hypertension on atherosclerosis generally requires a critical level of circulating lipoproteins. Enhanced atherosclerosis is not observed in hypertensive animals without hyperlipoproteinemia or in human subjects with low lipoprotein concentrations.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Recent advances in molecular pathology. The effects of hypertension on the arterial wall. 638 Oct 89

The present paper deals with the particular behavior of the complexes formed between pancreatic elastase and seric inhibitors in the Pig, when they were set in contact with homologous elastin. The previously known values of dissociation constants of alpha 1-antiprotease-elastase and alpha 2-macroglobulin-elastase complexes indicated they were very stable and almost irreversible. Nevertheless, our results suggest that, when the overall complexes between porcine pancreatic elastase and seric inhibitors were isolated in non drastic conditions, they might develop an elastolytic activity against elastin fibers. This result is important as regards atherosclerosis--in Human--where a destruction of elastin is involved at a early stage of the disease.
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PMID:[Complexes of "pancreatic elastase-seric inhibitors" in swine: their behavior in the presence of homologous aortic elastin]. 640 67

Thioglycollate-elicited mouse peritoneal macrophages were cultured in contact with the mixture of extracellular matrix proteins produced by rat smooth muscle cells in culture. Both live macrophages and their conditioned media hydrolyzed glycoproteins, elastin, and collagen. Live macrophages also degraded extracellular connective tissue proteins secreted by endothelial cells and fibroblasts. The glycoproteins in the matrix markedly inhibited the rate of digestion of the other macromolecules, particularly elastin. When plasminogen was added to the matrix, activation of plasminogen to plasmin resulted in the hydrolysis of the glycoprotein components, which then allowed the macrophage elastase easier access to its substrate, elastin. Thus, although plasmin has no direct elastinolytic activity, its presence accelerated the rate of hydrolysis of elastin and therefore the rate of matrix degradation. These findings may be important in an understanding of disease states, such as emphysema and atherosclerosis, that are characterized by the destruction of connective tissue.
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PMID:Degradation of connective tissue matrices by macrophages. II. Influence of matrix composition on proteolysis of glycoproteins, elastin, and collagen by macrophages in culture. 645 Feb 58

The biomechanical properties of rat aorta, muscle tendon and skin were studied after daily D-penicillamine treatment (500 mg/kg) for 5, 10 and 42 days. D-Penicillamine treatment for 5 days resulted in increased aortic extensibility. After long-term treatment the aorta exhibited a shift towards decreased extensibility and increased stiffness at small 'stress' values. Simultaneously the dry weight and diameter of the aortic samples were increased after D-penicillamine treatment for 42 days. After correction of the mechanical parameters for the increased amount of tissue of the samples, the stiffness at small 'stress' values was still increased and the mechanical stability at high 'stress' values retained. This is in contrast to the marked reduction in the strength of muscle tendon and skin of the same animals after D-penicillamine treatment for 42 days. This study demonstrates that a primary increase in the extensibility of aorta may elicit a reactive formation of vascular connective tissue. It is proposed that aortic smooth muscle cells are activated by an increased pulsatile distension of the vessel wall secondary to the early effect of D-penicillamine on collagen and elastin. The resulting excess deposition of collagen and elastin leads to increased stiffness, which may in turn increase the susceptibility of the aortic wall to hemodynamic injury. Consequently D-penicillamine may not as proposed counteract the development of atherosclerosis.
Atherosclerosis 1984 Aug
PMID:Effect of D-penicillamine on the mechanical properties of aorta, muscle tendon and skin in rats. 647 73

Although the laser has been demonstrated to vaporize coronary artery plaque, there is little information about its ability to resect or vaporize the range of plaques present in peripheral vessels. This study attempts to determine the ability of the argon laser to resect all grades of atherosclerotic plaque, the risk of perforation during plaque resection, the effects on surrounding arteries, and the effect of different transmission media (air, saline solution, and blood) on the delivery of laser energy to the vessel. Seventy-five adult human cadaveric aortic specimens with a range of atherosclerosis from grossly normal artery to extensive calcification with ulceration were exposed to variable energy densities (200 to greater than 20,000 J/cm2) within 48 hours of harvesting. Specimens were examined grossly for the visual effects of laser and microscopically after preparation with hematoxylin-eosin, trichrome, and/or Verhoeff's elastin stains. Our results indicate that normal arteries and noncalcified plaques absorb laser energy and are vaporized. As the atherosclerosis becomes more complex with calcification, calcified regions are not vaporized and cannot be resected. In normal arteries and noncalcified plaque, perforation times were less than 5 seconds. Where palpable calcification was present in atherosclerotic lesions, average perforation time was doubled. In some vessels areas of calcification prevented wall perforation, but areas of subintimal hemorrhage perforated rapidly because of the selective absorption of laser energy by the red color of hemorrhagic tissue. These results remain the same when saline solution is used as a transmission media, although the amount of energy required to achieve the effects is increased.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Acute effects of argon laser on human atherosclerotic plaque. 649 10


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