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)

The anomalous finding that very low density lipoprotein levels are relatively normal in patients with familial hyperchylomicronaemia has never been satisfactorily explained, particularly in view of the marked reduction or absence of peripheral lipoprotein lipase activity characteristic of this condition. I propose that the discrepancy between the plasma levels of the two triglyceride-rich lipoprotein fractions in these patients is due to the secretion by the liver of triglyceride in the form of chylomicron-like particles, rather than as very low density lipoprotein. The proposed "switch" in the spectrum of lipoproteins secreted by the liver is probably contingent upon the activity of the hepatic lipase present on the liver cell plasma membrane.
Atherosclerosis 1979 Sep
PMID:Why very low density lipoprotein levels are normal in familial hyperchylomicronaemia. 22 32

Low doses of heparin were injected into the brachial artery of three volunteers. The lipase activities in the deep vein of the same forearm, draining mainly muscle tissue, and in the artery were monitored over a 10-min period. Lipase activity, rapidly released by heparin in the deep vein, was immunologically similar to lipoprotein lipase (E.C. 3.1.1.3), i.e. (1) it did not react with antiserum against human post-heparin plasma hepatic lipase and (2) it was inhibited by an antiserum against bovine milk lipoprotein lipase, which cross reacts with human post-heparin plasma lipoprotein lipase. The evidence that human muscle contains lipoprotein lipase is discussed.
Atherosclerosis 1977 May
PMID:Heparin-induced release of lipase activity in the human forearm: an immunological study. 32 91

Three different assays for selective measurement of plasma lipoprotein lipase (LPL) and hepatic triglyceride lipase (H-TGL) were compared. These were: an immunochemical method based on enzyme antibody precipitation (IM), a procedure in which both enzymes were separated by affinity chromatography on small heparin--Sepharose columns (HS), and an assay in which one enzyme was inhibited by protamine sulfate (PS). Good correlations were found between the immunochemical and the heparin--Sepharose method, but not between these and the protamine sulfate assay procedure. The IM was then used to evaluate the effect of clofibrate on the two lipolytic enzymes. It was found that both in normals and in patients with Type IV hyperlipoproteinemia, clofibrate treatment leads to a specific increase of plasma LPL while H-TGL activity remains almost unaffected. The magnitude of the LPL response was different in normals and in patients with endogenous hyperlipoproteinemia. Furthermore, in normals the maximal increase of LPL activity was already reached one week after drug treatment was begun, while in hypertriglyceridemic patients, this effect was not evident prior to four weeks of clofibrate treatment. The marked enzyme increase following clofibrate administration indicates that an increased peripheral removal rate for triglycerides is one major mechanism responsible for the lipid-lowering effect of this drug.
Atherosclerosis 1977 Apr
PMID:Comparison of assay methods for selective measurement of plasma lipase. The effect of clofibrate on hepatic and lipoprotein lipase in normals and patients with hypertriglyceridemia. 85 26

Twelve male patients with hyperlipoproteinemia were treated with clofibrate, 1 g twice daily. Serum triglyceride concentration decreased on the average 28 +/- 6%. No significant change of serum cholesterol concentration occurred. Post heparin plasma lipoprotein lipase activity isolated and partially purified by heparin Sepharose affinity chromatography was determined quantitatively. During the clofibrate treatment this enzyme activity increased 48 +/- 9%. The post heparin hepatic triglyceride lipase did not change significantly. The possibility that the serum triglyceride-lowering effect of clofibrate might partly be explained by an increased removal rate of triglyceride rich lipoproteins through increased lipoprotein lipase activity is discussed.
Atherosclerosis 1977 Aug
PMID:The effect of treatment with clofibrate on hepatic triglyceride and lipoprotein lipase activities of post heparin plasma in male patients with hyperlipoproteinemia. 88 4

Human post-heparin plasma contains at least two different triglyceride lipases (TGL). The plasma lipolytic activity has been attributed to extra-hepatic and hepatic origin. Both post-heparin triglyceride lipases were partially purified and characterized. With heparin-Sepharose 4 B affinity chromatography it was possible to partially purify human adipose tissue lipoprotein lipase (LPL) as well as a lipase from human liver. The effects of NaCl, pre-heparin plasma, pH and temperature on these two tissue lipases and plasma lipases were studied in parallel. Antibodies were produced against plasma hepatic triglyceride lipase (plasma H-TGL) that did not cross react with LPL. TGL activity of human liver was completely inhibited by antibodies against plasma H-TGL. From these results it appears that human post-heparin plasma contains two triglyceride lipase activities which originate from liver and extra-hepatic tissues such as adipose tissue.
Atherosclerosis
PMID:A comparative study of human tissue and post-heparin plasma triglyceride lipases. 100 6

Human hepatic lipase (HL) is a 477 residue glycoprotein that hydrolyzes triglycerides from plasma lipoproteins. Familial HL deficiency is a rare recessive disorder that is characterized by premature atherosclerosis and abnormal circulating lipoproteins. While studying the HL gene from the world's index family with HL deficiency, we identified four coding sequence variants of HL, one in each of exons 4, 5, 6, and 8. In this report we present the genetic basis for two new HL gene variants, one in each of exons 3 and 5. All six HL DNA variants are single base pair changes. Two variants (at codons 133 and 202) are diallelic DNA polymorphisms that are silent at the amino acid level. One variant (V73M) is an allele that defines an uncommon HL isoprotein. One variant (N193S) has two alleles of approximately equal frequency in the population that specify two common HL isoproteins. Two variants (S267F and T383M) are rare mutations found to date only in HL deficient subjects and their relatives. Of the six HL variants described to date, only S267F and T383M are associated with hyperlipidemia.
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PMID:Human hepatic lipase mutations and polymorphisms. 130 39

Lipids, apoproteins and associated enzyme activities in type 2 diabetic end-stage renal disease (ESRD) were compared with that in nondiabetic ESRD and normal controls. Of the 40 uremic patients with non-insulin-dependent diabetes mellitus, 20 patients were receiving stable continuous hemodialysis treatment (CHT). Of the 39 patients with nondiabetic ESRD, 21 were undergoing CHT. Patients with nondiabetic ESRD exhibited elevated levels of serum triglyceride and a marked reduction in high-density-lipoprotein (HDL) cholesterol. Concentrations of serum apolipoprotein (Apo) C-3 were higher than in controls, whereas mean levels of serum Apo E were lower. The concentrations of serum Apo A-1 and Apo A-2 decreased with diminished lecithin: cholesterol acyltransferase activity. Lipoprotein lipase activity decreased in undialysed patients, and hepatic triglyceride lipase activity decreased significantly throughout the observation. Patients with diabetic ESRD exhibited elevated serum Apo B and normal serum Apo E levels, besides the lipid and Apo abnormalities observed in nondiabetic ESRD. Moreover, a prominent reduction in serum Apo A-1 was found in dialysed diabetic patients. The Apo B/Apo A-1 ratio was significantly higher in diabetic ESRD than in nondiabetic patients undergoing CHT. These results indicate that lipid abnormalities are accelerated in diabetic ESRD and may constitute a serious risk for the development of atherosclerosis.
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PMID:Comparison of lipids, apoproteins and associated enzyme activities between diabetic and nondiabetic end-stage renal disease. 150 37

This study was conducted to investigate acute effects of smoking on platelet function, endothelial cells and plasma lipids and to follow these parameters after Aspirin ingestion. Twelve fasting smokers each inhaled the smoke of one cigarette. Blood was drawn before and 10 min after smoking. Plasma nicotine, measured by gas chromatography, increased from 13.48 before smoking to 78.41 nM after smoking. Platelet aggregation to thrombin and ADP increased significantly (P less than 0.001). The platelet aggregate ratio decreased from 0.95 to 0.75 (P less than 0.005). Plasma beta-thromboglobulin also increased in post-smoking samples as measured using radioimmunoassay. 'Circulating endothelial cells' increased significantly after smoking (P less than 0.005). Triglycerides decreased (P less than 0.005) in plasma and in the VLDL fraction (P less than 0.05). Both post-smoking plasma free fatty acids and free glycerol increased, respectively, as compared with respective values. Lipase activity ascribable to lipoprotein lipase and hepatic lipase, absent in pre-smoking plasma samples, could be detected in post-smoking plasma without heparin injection. At least 1 week later, the subjects returned to follow an identical protocol except that they had ingested Aspirin (650 mg) 10-14 h before blood sampling. The same parameters were measured before and after smoking the same cigarette. Except for plasma nicotine, all the smoking-induced changes were abolished by ingestion of Aspirin. The results of this study indicate an interrelationship between platelet hyperactivity, endothelial injury and plasma lipids. They also demonstrate an inhibition of the major smoking-induced changes by Aspirin in the presence of high plasma nicotine levels. It is concluded that Aspirin may offset several of the deleterious acute effects of smoking. However, our conclusions cannot be, in any way, extended for long-term effects of both smoking and Aspirin treatment. Based on these data, it is suggested that there may be some links between platelet hyperactivity, endothelium injury and plasma lipids.
Atherosclerosis 1992 Apr
PMID:Acute influence of smoking on platelet behaviour, endothelium and plasma lipids and normalization by aspirin. 146 56

Studies of lipoproteins in this homogenous study population indicate clear and consistent associations between obesity and abnormalities in lipoproteins. These include both increases in VLDL and lower HDL, which were observed in both men and women. A high production of total body cholesterol in obese subjects, probably associated with increased flux of glucose and free fatty acids, leads to a greater production of VLDL. This, in turn, creates a greater flux of metabolic products of VLDL either back to the liver or through LDL. Obesity induces an increase in hepatic lipase, perhaps in women because of lower estrogen levels, which is associated with lower HDL concentrations, and altered HDL composition. Several of these observed changes, such as the greater proportion of VLDL remnants, the greater flux of particles through the LDL compartment, and the altered HDL composition, may be associated with increased atherosclerosis. However, preliminary data do not show a relationship between obesity and death from coronary heart disease in this population. More studies are needed to resolve this apparent conflict.
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PMID:Obesity, lipoproteins, and heart disease. 157 83

Silent myocardial ischemia (SI), an asymptomatic manifestation of coronary artery disease (CAD), was identified in 10% of apparently healthy nonsmoking, nondiabetic older (60 +/- 7 years, mean +/- SD) men with normal plasma cholesterol levels. We hypothesized that in the absence of other major risk factors for CAD, the men with SI would have reduced plasma levels of high density lipoprotein (HDL) and HDL2 subspecies due to an upper-body fat distribution (waist-to-hip ratio [WHR]), hyperinsulinemia, and abnormal postheparin plasma lipoprotein lipase (LPL) and hepatic lipase (HL) activities. Compared with 47 normal control subjects of similar age, obesity, and maximal aerobic capacity, the 18 men with SI had higher plasma triglyceride (TG) (162 +/- 71 versus 102 +/- 39 mg/dl, p less than 0.001) and lower HDL-C (33 +/- 6 versus 37 +/- 7 mg/dl, p less than 0.02) levels with no difference in low density lipoprotein cholesterol level. The HDL2b and HDL2a subspecies measured by gradient gel electrophoresis were also lower in the men with SI (p less than 0.01). The plasma glucose and insulin responses during an oral glucose tolerance test were the same in both groups. Postheparin plasma HL activity was significantly higher in 12 men with SI than in 41 control subjects (34 +/- 8 versus 27 +/- 10 mumol/ml.hr-1, p less than 0.03) and was correlated with log insulin area (r = 0.36, p less than 0.05) and WHR (r = 0.32, p less than 0.05) in the control subjects but not in the men with SI. In the control group, the percent HDL2b subspecies was correlated inversely with postheparin plasma HL activity (r = -0.46, p less than 0.01, n = 41) as well as WHR (r = -0.49, p less than 0.001, n = 47) and log insulin area (r = -0.37, p less than 0.05, n = 47) but not in the men with SI. Postheparin LPL activity was the same in both groups of men and did not correlate with HDL, WHR, insulin, or plasma TG levels. As the control subjects and men with SI had comparable degrees of abdominal obesity and hyperinsulinemia, these results suggest that the reduced HDL-C levels in men with SI may be related to elevations in HL activity. Thus, abdominal obesity, hyperinsulinemia, elevated TG levels, and low HDL-C and HDL2 subspecies levels may predispose these older men to atherosclerosis.
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PMID:Reduced HDL2 cholesterol subspecies and elevated postheparin hepatic lipase activity in older men with abdominal obesity and asymptomatic myocardial ischemia. 161 6


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