UMLS:C0004153 - FACTA Search

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

The effects of protection of chylomicron remnants from oxidation on their uptake and induction of lipid accumulation in macrophages were investigated using chylomicron remnant-like particles (CRLPs) containing the lipophilic antioxidant drug, probucol, and macrophages derived from the human monocyte cell line, THP-1. The total lipid content of THP-1 macrophages was markedly higher (x2.2) after 48 h of incubation of THP-1 macrophages with CRLPs containing probucol (pCRLPs) when compared to CRLPs without probucol, and this was because of increases in triacylglycerol (x2.3) and cholesterol (x1.8) levels, while cholesteryl ester concentrations were not significantly changed. Determination of the uptake of CRLPs and pCRLPs by the cells using particles labelled with the fluorescent probe 1,1'-dioctadecyl-3,3,3'3'-tetramethylindo-carbocyanine perchlorate showed that pCRLPs are taken up at a faster rate than CRLPs. The synthesis of triacylglycerol, as measured by the incorporation of [(3)H]oleate and [(3)H]glycerol, was also increased in macrophages incubated with pCRLPs as compared to CRLPs without probucol, but phospholipid and cholesteryl ester formation from [(3)H]oleate was unaffected. In addition, no differences between the effects of CRLPs and pCRLPs on the expression of mRNA for a range of genes believed to be involved in lipoprotein uptake, intracellular lipid metabolism and the efflux of cholesterol from macrophages was detected. These results suggest that antioxidants carried in chylomicron remnants enhance lipid accumulation in macrophages by increasing the rate of uptake of the particles and raising the intracellular synthesis of triacylglycerol, but not cholesteryl ester, and that these effects are brought about by changes at the post-transcriptional level. Antioxidants carried in chylomicron remnants therefore may promote the development of atherosclerosis, and this is likely to be particularly important in conditions where clearance of remnants from the circulation is delayed.
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PMID:Protection of chylomicron remnants from oxidation by incorporation of probucol into the particles enhances their uptake by human macrophages and increases lipid accumulation in the cells. 1518 57

To investigate effects of supplementation of folic acid on the expression of adhesion molecules VCAM-1 in the aortas of rats with hyperhomocysteinemia. Thirty male SD rats (200 +/- 20 g) were invided into 3 groups (n = 10 for each group): control group(Control), high Met group(Met) and Met plus Folate group(Met + Folate), fed. for 45 days. Plasma Hcy levels were higher with the high-methionine diet (140.68 +/- 36.87 micromol/L vs 6.47 +/- 1.10 micromol/L in control rats) an effect which was reduced by folate. Respectively, the aortic expression of adhesion molecules VCAM-1 at protein and mRNA levels were higher in the Met groups than those in the control groups or the Met + Folate groups. A high methionine diet for 45 days was sufficient to induce hyperhomocysteinemia. Folate supplementation prevented elevation of Hcy levels in the blood, and reduced expression of the adhesion molecule VCAM-1. Hyperhomocysteinemia is now regarded as one of the important risk factors for cardiovascular and cerebralvascular disorders.[Welch GN, Loscalzo J. Homocysteine and atherothrombosis. N Engl J Med 1998; 38(15):1042-50.] Several plausible mechanisms for Hcy-induecd atherosclerosis have been proposed. These include endothelial dysfunction, enhancement of oxidative stress, reduction in NO bioavailability, and augmentation of thrombus formation.[Holven KB, Holm T, Aukrust P, et al. Effect of folic acid treatment on endothelium-dependent vasodilation and nitric oxide-derived end products in hyperhomocysteinemic subjects . Am J Med 2001;110(7):536-42; Guba SC, Fonseca V, Fink LM. Hyperhomocysteinemia and thrombosis. Semin Thromb Hemost 1999;25(3):291-309.] However, the precise molecular mechanism is still unclear. Recent reports have suggested a role for inflammatory processes in the pathogenesis of atherosclerosis.[Gerard C, Rollins BJ. Chemokines and disease. Nat Immunol 2001;2(2):108-15.] Dysfunction of endothelial cells is the key process promoting inflammatory reactions. On injury, endothlial cells are capable of producing various cytokines that participate in inflammatory reactions in the arterial wall. Although results from in vitro studies suggest that Hcy, at pathophysiological concentrations, stimulates chemokine expression in vascular cells, it is unknown whether hyperhomocysteinemia can initiate similar changes, leading to enhanced momocyte adhesion/binding to the vascular endothelium in vivo.[Zeng X, Dai J, Remick DG, Wang X. Homocysteine mediated expression and secretion of monocyte chemoattractant protein-1 and interleukin-8 in human monocytes. Circ Res 2003;93(4):311-20.] On the basis of the potential pathogenic role of chemokines in atherogenesis, the objective of the present study was to investigate that homocsteine may exert its effect in part though adhesion molecules VCAM-1 and that folic acid supplementation may downregulate these inflammatory responses. Male Sprague-Dawley rats (bred from animal centers of Tongji Medical College, Huazhong Science and Technology University) aged 8 weeks were divided into 3 groups(n=10 for each group) and maintained for 45 days on the following diets before the experiments: (1) regular diet; (2) high-metheionine diet, consisting of regular diet plus 1.7% methionine; and (3) high-methionine plus folate -rich diet, consisting of regular diet plus 1.7% methionine and 0.006% folate.[Boisvert WA, Curtiss LK, Terkeltaub RA. Interleukin-8 and its receptor CXCR2 in atherosclerosis. Immunol Res 2000;21(2-3):129-d37.] Plasma and serum samples wee colleced and stored at -80 degrees C after 45 days until analysis. The plasma homocysteine concentration of rats in three groups were determined by high-pressue liquid chromatography. To detect the endothelial expression of adhesion molecules VCAM-1, the thoracic aorta was isolated and dived into segments. These segments were immersion-fixed in 10% neutral-buffered formalin overlight and then embedded in paraffin. Sequential 5 mum paraffin-embedded cross sections were prepared. Immunohistochemical analyisis was performed to detect vascular cell adhesion molecule(VCAM)-1, The fixed cryosections were immediately blcked in 10% horse serum and phosphate baffered saline(PBS) at room temperature for 30 min. Goat polyclonal andibodies against rat VCAM-1(Santa Cruz Biotechnology) were diluted 1:100 in PBS and incubated with the cryosections for 1 h of room temperature. After three washes, the sections were incubated with biotin-conjugated rabbit anti-goat immunoglobulins(Dako) at 1:250 dilution in PBS. After three washes, the samples were mounted in 90% glycerol-PBS. Photographs were taken by use of a light microscope at a mignification of x200.
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PMID:Folic acid reduces adhesion molecules VCAM-1 expession in aortic of rats with hyperhomocysteinemia. 1618 51

Developmental exposure to chlorpyrifos alters cell signaling both in the brain and in peripheral tissues, affecting the responses to a variety of neurotransmitters and hormones. We administered 1 mg/kg/day chlorpyrifos to rats on postnatal days 1-4, a regimen below the threshold for systemic toxicity. When tested in adulthood, chlorpyrifos-exposed animals displayed elevations in plasma cholesterol and triglycerides, without underlying alterations in nonesterified free fatty acids and glycerol. This effect was restricted to males. Similarly, in the postprandial state, male rats showed hyperinsulinemia in the face of normal circulating glucose levels but demonstrated appropriate reduction of circulating insulin concentrations after fasting. These outcomes and sex selectivity resemble earlier findings at the cellular level, which identified hepatic hyperresponsiveness to gluconeogenic inputs from beta-adrenoceptors or glucagon receptors. Our results thus indicate that apparently subtoxic neonatal chlorpyrifos exposure, devoid of effects on viability or growth but within the parameters of human fetal or neonatal exposures, produce a metabolic pattern for plasma lipids and insulin that resembles the major adult risk factors for atherosclerosis and type 2 diabetes mellitus.
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PMID:Developmental exposure of rats to chlorpyrifos elicits sex-selective hyperlipidemia and hyperinsulinemia in adulthood. 1620 36

Fenofibrate, a selective (1)PPAR-alpha activator, is prescribed to treat human dyslipidemia. The aim of this study was to delineate the mechanism of fenofibrate-mediated reductions in adiposity, improvements in insulin sensitivity, and lowering of triglycerides (TG) and free fatty acids (FFA) and to investigate if these favorable changes are related to the inhibition of lipid deposition in the aorta. To test this hypothesis we used male LDLr deficient mice that exhibit the clinical features of metabolic syndrome X when fed a high fat high cholesterol (HF) diet. LDLr deficient mice fed HF diet and simultaneously treated with fenofibrate (100 mg/kg body weight) prevented development of obesity, lowered serum triglycerides and cholesterol, improved insulin sensitivity, and prevented accumulation of lipids in the aorta. Lowering of circulating lipids occurred via down-regulation of lipogenic genes, including fatty acid synthase, acetyl CoA carboxylase and diacyl glycerol acyl transferase-2, concomitant with decreased liver TG and cholesterol, and TG output rate. Fenofibrate also suppressed liver apoCIII mRNA levels and markedly increased lipoprotein lipase mRNA levels, known to enhance serum TG catabolism. In addition, fenofibrate profoundly reduced epididymal fat and mesenteric fat mass to the levels seen in lean mice. The reductions in body weight were associated with elevation of hepatic uncoupling protein 2 (UCP2) mRNA, a concomitant increase in the ketone body formation, and improved insulin sensitivity associated with tumor necrosis factor-alpha reductions and phosphoenol pyruvate carboxykinase down-regulation. These results demonstrate that fenofibrate improves lipid abnormalities partly via inhibition of TG production and partly via clearance of TG-rich apoB particles by elevating LPL and reduced apoCIII. The prevention of obesity development occurred via energy expenditure. Fenofibrate-mediated hypolipidemic effects together with improved insulin sensitivity and loss of adiposity led to the reductions in the aortic lipid deposition by inhibiting early stages of atherosclerosis possibly via vascular cell adhesion molecule-1 (VCAM-1) modulation. These results suggest that potent PPAR-alpha activators may be useful in the treatment of syndrome X.
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PMID:Peroxisome proliferator-activated receptor-alpha selective ligand reduces adiposity, improves insulin sensitivity and inhibits atherosclerosis in LDL receptor-deficient mice. 1647 80

Vascular adventitial lesion as a new etiological factor of atherosclerosis (AS) has been confirmed by the results of several different animal models, and some evidence supports adventitial inflammation as the main cause, but the exact mechanism is still elusive. The data from some studies confirm that some link exists between the adventitial inflammation (which also might happen in the periadventitial fat) and atherosclerotic lesions. Aquaporin7 (AQP7) as an aquaglyceroporin, which regulates the permeation of glycerol through the cell membrane and located in the adipose tissue, shows some relationship with obesity. The result of the studies about AQP7-knockout mice and different expression of AQP7 in the cutaneous abdominal adipose tissue among people with different body types proved this phenomenon. Meanwhile, some degree of dysfunction of AQP7 has been proved in the obese. Until now, no study has shown us the data on the correlation of the expression of AQP7 in the periadventitial fat with the severity of atherosclerotic lesions. It is proposed that dysfunction of AQP7 in the periadventitial fat may trigger the adventitial inflammation. Attempts to confirm this hypothesis may lead to new directions in the study of the pathogenesis of AS and the development of a novel agent for this disorder.
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PMID:Dysfunction of AQP7 in the periadventitial fat: A novel trigger of atherosclerosis. 1756 58

The Hyplip2 congenic mouse strain contains part of chromosome 15 from MRL/MpJ on the BALB/cJ background. Hyplip2 mice show increased plasma levels of cholesterol and predominantly triglycerides (TGs) and are susceptible to diet-induced atherosclerosis. This study aimed at elucidation of the mechanism(s) explaining the hypertriglyceridemia. Hypertriglyceridemia can result from increased intestinal or hepatic TG production and/or by decreased LPL-mediated TG clearance. The intestinal TG absorption and chylomicron formation were studied after intravenous injection of Triton WR1339 and an intragastric load of olive oil containing glycerol tri[(3)H]oleate. No difference was found in intestinal TG absorption. Moreover, the hepatic VLDL-TG production rate and VLDL particle production, after injection of Triton WR1339, were also not affected. To investigate the LPL-mediated TG clearance, mice were injected intravenously with glycerol tri[(3)H]oleate-labeled VLDL-like emulsion particles. In Hyplip2 mice, the particles were cleared at a decreased rate (half-life of 25 +/- 6 vs. 11 +/- 2 min; P < 0.05) concomitant with a decreased uptake of emulsion TG-derived (3)H-labeled fatty acids by the liver and white adipose tissue. The increased plasma TG levels in Hyplip2 mice do not result from an enhanced intestinal absorption or increased hepatic VLDL production but are caused by decreased LPL-mediated TG clearance.
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PMID:The Hyplip2 locus causes hypertriglyceridemia by decreased clearance of triglycerides. 1760 25

Obstructive sleep apnea (OSA), a condition leading to intermittent hypoxia (IH) during sleep, has been associated with dyslipidemia, atherosclerosis, and increased cardiovascular mortality. We previously showed in C57BL/6J mice that IH causes hypercholesterolemia and upregulation of sterol regulatory element binding protein (SREBP)-1, a transcription factor of lipid biosynthesis in the liver. The goal of the present study was to provide mechanistic evidence that IH causes hypercholesterolemia via the SREBP-1 pathway. We utilized mice with a conditional knockout of SREBP cleavage-activating protein (SCAP) in the liver (L-Scap- mice), which exhibit low levels of an active nuclear isoform of SREBP-1 (nSREBP-1). We exposed L-Scap- mice and wild-type (WT) littermates to IH or intermittent air control for 5 days. IH was induced during the 12-h light phase by decreasing Fi(O(2)) from 20.9% to 5% for a period of 30 s with rapid reoxygenation to 20.9% through the subsequent 30 s. In WT mice, IH increased fasting levels of serum total and HDL cholesterol, serum triglycerides, serum and liver phospholipids, mRNA levels of SREBP-1 and mitochondrial glycerol-3-phosphate acyltransferase (mtGPAT), and protein levels of SCAP, nSREBP-1, and mtGPAT in the liver. In L-Scap- mice, IH did not have any effect on serum and liver lipids, and expression of lipid metabolic genes was not altered. We conclude that hyperlipidemia in response to IH is mediated via the SREBP-1 pathway. Our data suggest that the SREBP-1 pathway could be used as a therapeutic target in patients with both OSA and hyperlipidemia.
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PMID:Effect of deficiency in SREBP cleavage-activating protein on lipid metabolism during intermittent hypoxia. 1766 24

Platelet-activating factor (PAF), the potent phospholipid mediator of inflammation, is involved in atherosclerosis. Platelet-activating factor-acetylhydrolase (PAF-AH), the enzyme that inactivates PAF bioactivity, possesses both acetylhydrolase and transacetylase activities. In the present study, we measured acetylhydrolase and transacetylase activities in human atherogenic aorta and nonatherogenic mammary arteries. Immunohistochemistry analysis showed PAF-AH expression in the intima and the media of the aorta and in the media of mammary arteries. Acetylhydrolase and transacetylase activities were (mean +/- SE, n = 38): acetylhydrolase of aorta, 2.8 +/- 0.5 pmol/min/mg of tissue; transacetylase of aorta, 3.3 +/- 0.7 pmol/min/mg of tissue; acetylhydrolase of mammary artery, 1.4 +/- 0.3 pmol/min/mg of tissue (P < 0.004 as compared with acetylhydrolase of aorta); transacetylase of mammary artery, 0.8 +/- 0.2 pmol/min/mg of tissue (P < 0.03 as compared with acetylhydrolase of mammary artery). Lyso-PAF accumulation and an increase in PAF bioactivity were observed in the aorta of some patients. Reverse-phase HPLC and electrospray ionization mass spectrometry analysis revealed that 1-O-hexadecyl-2 acetyl-sn glycero-3-phosphocholine accounted for 60% of the PAF bioactivity and 1-O-hexadecyl-2-butanoyl-sn-glycerol-3-phosphocholine for 40% of the PAF bioactivity. The nonatherogenic properties of mammary arteries may in part be due to low PAF formation regulated by PAF-AH activity. In atherogenic aortas, an imbalance between PAF-AH and transacetylase activity, as well as lyso-PAF accumulation, may lead to unregulated PAF formation and to progression of atherosclerosis.
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PMID:Platelet-activating factor acetylhydrolase and transacetylase activities in human aorta and mammary artery. 1858 71

We examined the effects of acute, food-induced moderate increase of plasma uric acid (UA) on arterial stiffness and markers of oxidative damage in plasma in healthy males exposed to 100% normobaric oxygen. Acute elevation of plasma UA was induced by consumption of red wine, combination of ethanol and glycerol, or fructose. By using these beverages we were able to separate the effects of UA, wine polyphenols and ethanol. Water was used as a control beverage. Ten males randomly consumed test beverages in a cross-over design over the period of 4 weeks, one beverage per week. They breathed 100% O(2) between 60(th) and 90(th)min of the 4-h study protocol. Pulse wave augmentation index (AIx) at brachial and radial arteries, plasma antioxidant capacity (AOC), thiobarbituric acid-reactive substances (TBARS), lipid hydroperoxides (LOOH) assessed by xylenol orange method, UA and blood ethanol concentrations were determined before and 60, 90, 120, 150 and 240 min after beverage consumption. Consumption of the beverages did not affect the AIx, TBARS or LOOH values during 60 min before exposure to hyperoxia, while AOC and plasma UA increased except in the water group. Significant increase of AIx, plasma TBARS and LOOH, which occurred during 30 min of hyperoxia in the water group, was largely prevented in the groups that consumed red wine, glycerol+ethanol or fructose. In contrast to chronic hyperuricemia, generally considered as a risk factor for cardiovascular diseases and metabolic syndrome, acute increase of UA acts protectively against hyperoxia-induced oxidative stress and related increase of arterial stiffness in large peripheral arteries.
Atherosclerosis 2009 Nov
PMID:Acute, food-induced moderate elevation of plasma uric acid protects against hyperoxia-induced oxidative stress and increase in arterial stiffness in healthy humans. 1945 84

Plasmalogens are a specific glycerophospholipid class containing a vinyl ether moiety at the sn-1-position of the glycerol backbone. The high susceptibility of this vinyl ether bond to oxidative damage and traces of acids may indicate the possible function of plasmalogens in biological systems: The regarded cell-internal antioxidative defense of membranes by protecting other phospholipids or lipoprotein particles against oxidative stress is controversial. Reactive oxygen species preferably affect the vinyl ether function as well as the olefinic acyl residues at the sn-2-position of plasmalogens. This review is dedicated to the role of plasmalogens in different cells and tissues as spermatozoal cells or brain tissue. The first chapter of this review will discuss the molecular structure and chemistry of plasmalogen molecules, their distributions in cells and tissues and the species-specificity. In the second chapter their functions as lipid mediators will be considered and the controversial antioxidative function will be discussed. The supposed function of plasmalogens as "scavengers" for reactive oxygen species (ROS) in biological membranes is challenged by the finding that plasmalogen oxidation products as alpha-hydroxyaldehydes and plasmalogen epoxides accumulate in all chronic diseases as atherosclerosis and myocardial infarction, upon aging as well as in Alzheimers disease and other neuropathological conditions. All these conditions, characterized by increased membrane instability and oxidative damage, will be reviewed in chapter three. Chronically proceeding processes can be described by permanently invading polymorphonuclear neutrophils into inflammatory loci. The degranulation of the azurophilic granula in polymorphonuclear leukocytes causes the release of highly reactive substances, for instance the myeloperoxidase-generated hypochlorous acid (HOCl) acting as effective oxidant. Therefore, special attention will be paid to neutrophil-derived HOCl. The last chapter deals with currently used methods of detecting plasmalogens and their degradation products. Although chromatographic methods will be also discussed, special attention will be given to (31)P NMR spectroscopy and soft ionization techniques of mass spectrometry as electrospray ionization or matrix-assisted laser desorption and ionization time-of-flight mass spectrometry.
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PMID:Plasmalogens in biological systems: their role in oxidative processes in biological membranes, their contribution to pathological processes and aging and plasmalogen analysis. 1951 79

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