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

The small molecular weight apolipoproteins of pig very low density lipoprotein were investigated following their separation by gel filtration and ion exchange chromatography. Gel filtration through Sephadex G-200 in 6 M urea, produced essentially the same elution profile to that obtained after filtration of human very low density apolipoprotein. However, separation of the pig Sephadex fraction corresponding to human C proteins on DEAE-cellulose columns revealed the presence of only one major peptide and minor quantities of several others. Some properties of three apparent homogeneous fractions and one heterogeneous DEAE fraction were investigated. Unlike human apoprotein CII apoprotein, none of the pig peptides studied activated cow's milk lipase and sialic acid was not detected in any of the three purified C peptides of pig VLDL. The amino acid compositions of the pig peptides were different to those reported for human C apoproteins. The carboxy terminal residue of the major pig C peptide was shown to be serine. The differences so far revealed between pig and human C peptides need further investigation especially since this animal is regarded as a suitable model for investigating human lipoprotein metabolism and the development of atherosclerosis.
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PMID:Characterisation of the small molecular weight apolipoproteins from pig plasma very low density lipoprotein. 17 51

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

We studied the effect of heparin on proteoglycan synthesis by bovine aortic smooth muscle cells in culture. Confluent, growth-arrested cells were incubated with [35S]sulfate, [3H]glucosamine or [3]serine in the presence of 0-600 micrograms/ml heparin. Metabolically labeled proteoglycans secreted into the culture medium and associated with the cell layer were analyzed. In cultures treated with heparin there was a dose-dependent increase in [35S]sulfate incorporation into secreted proteoglycans which reached a maximum (35% above controls) at 100 micrograms/ml heparin. At higher concentrations of heparin, the stimulatory activity declined and finally disappeared. Radioactivity in cell-associated proteoglycans increased significantly (16% above controls) only in cultures treated with 100 micrograms/ml heparin. Heparin also produced similar increases in the incorporation of [3H]glucosamine and [3H]serine into secreted and cell-associated proteoglycans. While chondroitin sulfate, dermatan sulfate and heparan sulfate were elevated in the media, only chondroitin sulfate and heparan sulfate were increased in the cell layer. Heparin did not alter the degradation of proteoglycans. Heparin, while inhibiting the proliferation of subconfluent smooth muscle cells, also stimulated to a greater extent the incorporation of [35S]sulfate into proteoglycans. Other glycosaminoglycans, such as heparan sulfate, dermatan sulfate, heparin hexasaccharide and Sulodexide caused a significant but lesser stimulation of proteoglycan synthesis, while chondroitin sulfates and hyaluronic acid had no effect. Gel filtration chromatography of proteoglycans and their constituent glycosaminoglycans from heparin-treated and untreated cultures showed no differences in their molecular size. The results indicate that heparin can stimulate proteoglycan synthesis by vascular smooth muscle cells irrespective of their state of proliferation. This might have implications in vessel wall repair and arterial wall lipid deposition.
Atherosclerosis 1992 Jun
PMID:Heparin stimulates proteoglycan synthesis by vascular smooth muscle cells while suppressing cellular proliferation. 163 67

A buffer extract from homogenized human aorta was applied to a Bio-Gel A-15m column, and two cholesterol-containing peaks were resolved. Both fractions of aortic lipoproteins present in the extracts from normal and atherosclerotic intima and stimulated cholesteryl ester (CE) synthesis in J774 mouse macrophages caused unregulated loading with CE. The Vmax of CE formation in the presence of both fractions correlated with the degree of intimal atherosclerosis. An excess of both fractions did not inhibit the uptake of malondialdehyde-treated low density lipoproteins by macrophages; their interaction with the cells was not inhibited either by fucoidin or by dextran sulfate. The uptake of labeled LDL by human fibroblasts was markedly decreased with excess of both fractions. Aortic lipoprotein-mediated CE synthesis (for both fractions) was completely blocked by EDTA in fibroblasts, being decreased by 50% in macrophages.
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PMID:[Stimulation of cholesterol ester synthesis in macrophages by lipoproteins from normal and atherosclerotic human aorta intima]. 239 79

Aortic areas predisposed to early atherosclerosis in swine demarcated by Evans blue uptake (blue areas) show preferential intimal penetration by blood monocytes before and during lesion formation. These cells are thought to be the major source of foam cells in these early lesions. To examine mechanisms controlling monocyte migration into these areas, extracts of aortic tissue from both blue and white areas of hypercholesterolemic (H) and normal (N) swine were tested for chemotactic activity against monocytes from N and H swine and neutrophils from H swine. The data indicate that extracts of blue areas from H swine contained at least one, and possibly two, factors chemotactic only for monocytes from H swine, but not N swine. These factors were not present in similar extracts from white areas of H swine, or either blue or white area extracts from N swine. Gel filtration chromatography of crude blue area extracts separated two chemotactically active fractions of molecular weights 68,000 and 5000 that were not present in white area extracts and that elicited a positive chemotactic effect only for H swine monocytes. These findings provide a mechanism explaining our previous findings of preferential monocyte adhesion and intimal penetration in lesion-prone areas, and indicate that control of monocyte recruitment into the artery involves not only alteration of the arterial wall, but also functional changes in the circulating monocyte.
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PMID:Control of monocyte recruitment by chemotactic factor(s) in lesion-prone areas of swine aorta. 396 8

Heparin was fractionated on an affinity column of bovine milk lipoprotein lipase (LpL) immobilized to Affi-Gel-15. The bound heparin, designated high-reactive heparin (HRH), enhanced LpL activity, presumably by stabilizing the enzyme against denaturation. The unbound heparin fraction had no observable effect on the initial rate of enzyme activity. However, at longer times of incubation there was inhibition of LpL activity. LpL-specific HRH also showed a high, Ca2+-dependent precipitating activity towards human plasma low density lipoproteins (LDL). Since LpL and LDL both bind to heparin-like molecules at the surface of the arterial wall, we suggest that their similar heparin-binding specificity may have physiological consequences as it relates to the development of atherosclerosis.
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PMID:Heparin binding to lipoprotein lipase and low density lipoproteins. 404 7

Lipoproteins and glycosaminoglycans were isolated from human aorta fibrous plaque lesions by isotonic saline extraction and treatment with elastase. Hydrolysis by elastase, using suitable inhibitors of nonspecific proteases, yielded about twice the amount of cholesterol and four times more GAG than saline extraction. Bio-Gel A-50m column chromatography of elastase-solubilized materials gave a fraction which contained lipoproteins of 1.006 and 1.063 floating densities and hyaluronic acid. Immunologically the lipoproteins resembled serum apoB-containing lipoproteins. Two species of hyaluronates with estimated molecular weights of 400,000 and 75,000 were observed. In addition to hyaluronate, elastase solubilized other GAG which were not associated with lipoproteins. Association of hyaluronate as the only GAG in the elastase-solubilized lipoprotein fraction emphasizes the important role that hyaluronate may play in the aggregation or entrapment of macromolecules such as lipoproteins in the arterial connective tissue matrix.
Atherosclerosis 1980 May
PMID:Lipoprotein-hyaluronate associations in human aorta fibrous plaque lesions. 677 Aug 77

Gel-filtered platelets (GFP) from normal human subjects bound both low density lipoproteins (LDL) and high density lipoproteins (HDL). This binding was saturable and 125I-labelled lipoprotein uptake was inhibited by plasma. Platelets are also able to degrade lipoproteins but only to a limited extent. LDL appeared to compete with 125I-labelled HDL for platelet uptake, whereas the ability of HDL to displace 125I-LDL was limited. Cyclohexanedione-treated LDL (CHD-LDL), unlike CHD-HDL, did not compete with [125I]LDL for platelet accumulation, suggesting that arginine residues are necessary for LDL but not HDL binding. Addition of HDL or LDL to GFP did not alter platelet aggregation. However, in the presence of thrombin (0.5 U/ml), 1 mg/ml LDL incubated for 1 h at 23 degrees C enhanced platelet aggregation (215% increase) whereas HDL under similar conditions decreased aggregation by 53%. LDL also shortened the time of maximal aggregation whereas HDL had the opposite effect.
Atherosclerosis 1983 Mar
PMID:Platelet interaction with high and low density lipoproteins. 684 42

The nature of lipoprotein and elastin associated with hyaluronate in human atherosclerotic plaque tissue was studied by digesting the tissues with elastase. The elastase-solubilized lipoprotein-hyaluronate complexes, isolated by Bio-Gel A-50m column chromatography, contained 7.8 mg calcium/100 mg protein. The Sephadex G-200 chromatography of delipidated complexes yielded high (fraction I) and low (fraction II) molecular weight protein fractions. Dialysis of the complexes against 0.01% EDTA resulted in removal of fraction II. Fraction I reacted immunologically against antihuman LDL, and its amino acid composition resembled that of human apoB. Fraction II contained 5 peptide fragment and had high levels of nonpolar amino acids that are characteristic of elastin. However, these peptides also contained high levels of polar amino acids, thus resembling the plaque elastin. These findings suggest that certain regions of plaque elastin may have affinity for apoB containing lipoproteins and calcium.
Atherosclerosis
PMID:Lipoprotein-elastin interactions in human aorta fibrous plaque lesions. 690 18

Arterial smooth muscle cells cultured from normotensive and hypertensive rats incorporated [35S]sulfate into the extracellular and pericellular sulfated proteoglycans and endocytose extracellular [35S]proteoglycans at a significantly higher rate in the phase of logarithmic growth than did nondividing cells. 35S incorporation into proteoglycans was positively correlated with [3H]thymidine incorporation into the cellular TCA-precipitable material. The rates of [35S]proteoglycan synthesis and endocytosis per cell pr day were higher in smooth muscle cells from hypertensive than from normotensive animals, the observed differences being related to a higher average protein content of smooth muscle cells cultured from hypertensive rats as compared with cells of normotensive animals. Gel filtration under dissociative conditions separated the [35S]proteoglycans into high and low molecular weight fractions (A, B) differing in glycosaminoglycan composition and their ability to be endocytosed by smooth muscle cells. The relative proportion of the high molecular weight proteoglycan fraction A decreased continuously from sparse to confluent cell cultures.
Atherosclerosis 1982 Dec
PMID:[35S]proteoglycan metabolism of arterial smooth muscle cells cultured from normotensive and hypertensive rats. 715 1


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