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)

Atherosclerosis is associated with an accumulation of proteoglycans. Proteoglycans and/or glycosaminoglycans, in particular heparan sulfate, produced by endothelial cells are thought to play important roles in diverse vascular functions. Of particular note is that they possess anticoagulant functions, i.e., heparin-like antithrombin cofactor activity. Incubation of antithrombin III with endothelial cell cultures resulted in a specific, saturable binding of this protease inhibitor presumably to the endothelial cell surface. In addition, thrombin inactivation by antithrombin III was accelerated on the endothelial surface, providing strong evidence that heparan sulfate on the surface of endothelial cells exerts a heparin-like activity. beta-D-xyloside or cytokine treatments altered the synthesis of heparan sulfate on the endothelial cell surface, resulting in decreased anti-thrombin III binding and diminished heparin-like anticoagulant activity of endothelial cells. The modulation of endothelial heparin-like compounds by these pharmacologic or physiologic agents may have pathophysiologic implications in thrombosis as well as atherogenesis.
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PMID:Anticoagulant heparin-like glycosaminoglycans on endothelial cell surface. 174 77

Thrombin, a serine protease generated at sites of vascular injury, plays a role in the pathogenesis of atherosclerosis and restenosis after angioplasty. Adherence of monocytes to the endothelium and migration into the subendothelial space is an important early event in the pathogenesis of atherosclerosis. Monocyte chemoattractant protein 1 (MCP-1) may be an important mediator of monocyte recruitment to the tissue in this and other diseases. We have characterized the expression of MCP-1 in vascular smooth muscle cells (VSMCs) isolated from human renal artery and studied its regulation by thrombin. Serum-deprived cells release monocyte chemotactic activity that is neutralized (80%) by an MCP-1 antibody. The antibody recognized a 13- and 15-kD protein in smooth muscle cell-conditioned medium. Thrombin stimulates MCP-1 gene expression in a concentration- and time-dependent manner. An increase over basal levels was observed with concentrations of thrombin as low as 0.05 U/mL. The maximal effect occurred at 5 U/mL. The stimulatory effect was detected within 1 hour, reached a maximum at 3 hours, and was still present at 8 to 24 hours after the addition of thrombin. A concentration- and time-dependent effect of thrombin on MCP-1 gene expression was also found in rat VSMCs. The thrombin protease inhibitor hirudin blocked thrombin-induced MCP-1 expression. Thrombin stimulated the release of MCP-1 protein in conditioned medium of human VSMCs as measured by radioimmunoassay and chemotactic assay. Thrombin also increased monocyte chemotactic activity in short-term organ cultures of rat aortic rings and in first passage cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Thrombin regulates expression of monocyte chemoattractant protein-1 in vascular smooth muscle cells. 764 21

In some pathological states such as therosclerosis tissue destruction may be accelerated due to uncontrolled protease release of polymorphonuclear leukocytes and other events such as decreased concentration and/or the inactivation of main protease inhibitor molecules in the serum. In this study, the authors measured the elastase release of polymorphonuclear leukocytes which increased in atherosclerosis independently of the patients aged compared to healthy young subjects. These findings were similar to the response of polymorphonuclear leukocytes separated from healthy elderly subjects. Simultaneously, the main plasma proteinase inhibitors such as alpha-1-antitrypsin and alpha-2-macroglobulin in healthy and atherosclerotic subjects were determined. alpha-1-antitrypsin did not decrease significantly, whereas alpha-2-macroglobulin did in sera of atherosclerotic patients compared to age matched subjects (p < 0.05). In contrast, the activity of porcine pancreatic elastase was more effectively neutralized by the plasma obtained from healthy subjects suggesting diminished antiprotease activity of sera obtained from patients. The authors concluded that increased elastase release and decreased antiproteinase activity should be considered in atherosclerotic arterial wall damage. The similarity of the results in aged and therosclerotic subjects suggests that arteriosclerosis is an earlier aging process.
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PMID:[Serum elastin peptide concentration and human leukocyte elastase/antiproteinase balance in peripheral obstructive atherosclerosis]. 872 58

The multiligand receptor, low density lipoprotein receptor-related protein (LRP), is implicated in processes such as atherosclerosis and fibrinolysis through its mediation of the catabolism of lipoproteins, proteases, and protease inhibitor complexes. The hepatoma cell line Hep G2 expresses LRP and has been used widely to investigate the catabolism of LRP ligands including tissue-type plasminogen activator (tPA). However, the mechanism and degree by which tPA interacts with Hep G2 has been reported with some inconsistencies which may reflect variation in their level of LRP expression. To address this possibility we characterized, antigenically and functionally, LRP expression in high and low passage Hep G2 cells both from the parental line (ATCC sourced) and a cloned subline, a16. The LRP contribution to 125I-tPA binding varied from 65% for high passage a16 cells, to 20% for low passage parent cells as quantified by inhibition in the presence of 39-kD receptor associated protein (RAP) which prevents binding of all known LRP ligands. The same trend in LRP expression among Hep G2 sublines was further evident in their ability to degrade 125I-tPA and survive Pseudomonas exotoxin A challenge. These results imply wide variability in basal LRP expression among Hep G2 lines dependent on cell lineage and long-term culture conditions.
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PMID:Low density lipoprotein receptor-related protein (LRP) expression varies among Hep G2 cell lines. 961 Sep 60

Degranulated mast cells are present in the human arterial intima. After degranulation of rat serosal mast cells, the secreted neutral serine protease chymase remains bound to the heparin proteoglycan matrix of the exocytosed granules, forming granule remnants. Addition of granule remnants to human aortic intimal fluid results in proteolysis of the apoAI present in the intimal fluid, which contains physiological inhibitors of chymase. To study the physiological mechanism of this protection of granule remnant-bound chymase against its inhibitors, we performed experiments using HDL3 as substrate. Chymase, when bound to the heparin proteoglycans of granule remnants, but not when released from them, resisted inhibition by the mammalian protease inhibitors alpha1-antitrypsin, alpha2-antichymotrypsin, alpha2-macroglobulin, and eglin C. Importantly, the heparin proteoglycan-bound chymase, but not unbound chymase, degraded its inhibitor (alpha1-antitrypsin) in the presence of its substrate (HDL3). Finally, binding to heparin proteoglycans of a physiological inhibitor of chymase (mucus protease inhibitor (MPI)) or of another substrate of chymase (LDL) did not inhibit the degradation of HDL3 by granule remnant-bound chymase. This study demonstrates that binding of chymase to the heparin proteoglycan chains of the exocytosed mast cell granules allows the protease to remain active and degrade HDL3 in the presence of its physiological inhibitors and in the presence of high concentrations of LDL, such as are found in the interstitial fluid of the arterial intima.
Atherosclerosis 2001 Mar
PMID:Chymase bound to heparin is resistant to its natural inhibitors and capable of proteolyzing high density lipoproteins in aortic intimal fluid. 1122 30

Four cases of human immunodeficiency virus (HIV)-infected patients who developed coronary heart disease (CHD) while under treatment with a protease inhibitor (PI) are described, and the epidemiologic and clinical features of 18 cases reported in the literature are analyzed. Cardiac manifestations mostly included myocardial infarctions. Smoking and hyperlipidemia were the most common risk factors for CHD, reported in 72 and 81% of the patients, respectively. Hypercholesterolemia was observed in 75% of the cases at the time of the cardiovascular event. Ninety percent of the patients with pretreatment normal lipid values experienced a rise in the plasma lipid levels during PI therapy. Although a definite relationship between the development of CHD and HIV PIs can not be made, this analysis suggests that PI-induced hyperlipidemia may play a role in accelerating coronary atherosclerosis in patients with concomitant risk factors. Evaluation and control of risk factors for CHD should be performed in each patient for whom treatment with a PI is indicated.
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PMID:Coronary heart disease associated with the use of human immunodeficiency virus (HIV)-1 protease inhibitors: report of four cases and review. 1159 16

We report the case of a 40-year-old HIV-positive man, undergoing three-drug antiretroviral therapy for 2 years that included a protease inhibitor (ritonavir). The patient was admitted to our Coronary Care Unit with an acute anterior myocardial infarction. He smoked 20 cigarettes/day and had a family history of hypertension. At the time of hospitalization, triglyceride levels were found to be high (290 mg/dl). Metabolic alterations associated with the prolonged use of protease inhibitors, such as insulin resistance, dyslipidemia and lipodystrophy, have recently been described. This side effect may lead to premature coronary artery disease. Therefore it is mandatory to be aware that treatment with protease inhibitors in HIV-positive patients, despite survival prolongation and lowering of AIDS complications, may accelerate atherosclerosis and precipitate acute coronary events, especially in patients with pre-existing cardiovascular risk factors.
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PMID:[Acute myocardial infarct in HIV-positive patients in treatment with protease inhibitors]. 1177 17

We investigated the effect of antiretroviral therapy on vascular activation in 41 human immunodeficiency (HIV)--infected patients receiving a regimen that included either at least 1 protease inhibitor (PI; n = 21) or a nonnucleoside reverse-transcriptase inhibitor (NNRTI; n = 20). A control group of 21 healthy subjects was included for comparison. Levels of endothelial markers (soluble vascular cell adhesion molecule [sVCAM]--1, soluble intercellular adhesion molecule--1, and von Willebrand factor) were higher in HIV-infected persons before treatment than in control subjects and decreased significantly after 5--13 months of treatment. Levels of sVCAM-1 and von Willebrand factor correlated significantly with initial virus load. d-dimer concentrations also decreased significantly after initiation of treatment. PI- and NNRTI-containing regimens had similar effects. Therapy did not reduce levels of the soluble platelet (sP) activation markers sP-selectin and CD40 ligand. The inhibition of markers of vascular activation may counterbalance sequelae of therapy-induced dyslipidemia and potentially prevent development of atherosclerosis in HIV-infected patients.
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PMID:Antiretroviral therapy reduces markers of endothelial and coagulation activation in patients infected with human immunodeficiency virus type 1. 1186 97

Hyperlipidemia has been seen in patients receiving protease inhibitor-based antiretroviral therapy, prompting concern that such patients are at risk for accelerated coronary artery disease (CAD). To assess the risk of CAD in antiretroviral-treated HIV-infected men, we quantified coronary artery calcium (CAC), a sensitive and established marker of subclinical CAD, using electron beam computed tomography (EBCT) of coronary vessels. Sixty HIV-infected men who met the following criteria (cases) were enrolled in the study: age of 40 years or older; naive to antiretroviral therapy or use of a stable antiretroviral regimen for >or=6 months (mean duration, 25.9 months; 41 patients were receiving protease inhibitor therapy); and no known CAD or no use of lipid-lowering agents. EBCT-derived CAC scores, serum lipid levels, history of antiretroviral therapy, and risk factors for CAD were obtained. Each case was compared with three age-, sex-, and race-matched HIV-negative controls randomly selected from a database including >9000 patients who had undergone EBCT. We determined differences in the proportion of cases and controls with CAC scores of >0 (detectable calcium) and clinically significant CAC for age range. There were no statistically significant differences between the number of cases and controls with detectable CAC (33% and 39%, respectively) and clinically significant CAC (18% and 17%, respectively). This study suggests that the rate of coronary atherosclerosis among HIV-infected patients who receive short-term antiretroviral therapy with or without protease inhibitors is not higher than that among age-, sex-, and race-matched HIV-negative controls. These results need to be confirmed in larger long-term studies, with controls well matched for coronary risk factors.
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PMID:Electron beam computed tomography for assessment of coronary artery disease in HIV-infected men receiving antiretroviral therapy. 1872 10

In human occluded saphenous vein grafts, we previously demonstrated cytotoxic foam cells, presumably derived from macrophages engulfing platelets. In the present study, we investigated whether platelet phagocytosis occurs in human atherosclerotic plaques, whether this activates macrophages, and whether the platelet constituent, amyloid precursor protein (APP), was involved. Immunohistochemistry documented the presence of APP, beta-amyloid peptide (Abeta, cleaved from APP), and platelets (CD9), along with inducible NO synthase (iNOS) and cyclooxygenase-2, two markers of macrophage activation, around microvessels in advanced human carotid artery plaques (n=18). Abeta colocalized with iNOS-expressing macrophages that were often surrounded by platelets. In vitro, murine J774 and human THP-1 macrophages were incubated with or without washed human platelets. Coincubation of macrophages and platelets led to platelet phagocytosis (electron and confocal microscopy) and formation of lipid-, APP-, and Abeta-containing foam cells. These expressed iNOS mRNA (reverse transcription-polymerase chain reaction) and protein and produced nitrite and tumor necrosis factor-alpha (ELISA). Macrophage pretreatment with 4-(2-aminoethyl)benzenesulfonyl fluoride, a protease inhibitor, reduced APP processing and inhibited NO biosynthesis induced by platelet phagocytosis but not by lipopolysaccharides. Human atherosclerotic plaques and J774 and THP-1 macrophages contained mRNA of the APP-cleaving enzyme beta-secretase. This is the first demonstration of Abeta, a peptide extensively studied in Alzheimer's disease, in human atherosclerotic plaques. It was present in activated iNOS-expressing perivascular macrophages that had phagocytized platelets. In vitro studies indicate that platelet phagocytosis leads to macrophage activation and suggest that platelet-derived APP is proteolytically processed to Abeta, resulting in iNOS induction. This represents a novel mechanism for macrophage activation in atherosclerosis.
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PMID:Platelet phagocytosis and processing of beta-amyloid precursor protein as a mechanism of macrophage activation in atherosclerosis. 1206 14


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