Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.1.34 (lipoprotein lipase)
7,025 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of simvastatin (MK-733), a competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, on serum lipids, lipoproteins, and apolipoproteins were investigated in 29 patients (12 men, 17 women, aged 37 to 73) with moderate to severe hypercholesterolemia. It was given in doses of 2.5 mg/day for four months and 5 mg/day for the succeeding four months. Total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and apolipoprotein (apo) B decreased by 18% (263 +/- 7 mg/dl to 216 +/- 7 mg/dl, P less than 0.01), 24% (180 +/- 7 mg/dl to 136 +/- 7 mg/dl, P less than 0.01), and 21% (133 +/- 4 mg/dl to 104 +/- 3 mg/dl, P less than 0.01), respectively, four months after treatment. Similar reductions (17%, 24%, and 23%, respectively, P less than 0.01) were observed at eight months. A significant reduction in triglyceride (TG) was observed (173 +/- 15 mg/dl to 136 +/- 11 mg/dl at eight months, P less than 0.01), as was a significant increase in serum high-density lipoprotein cholesterol (HDL-C) (48 +/- 2 mg/dl to 52 +/- 2 mg/dl at eight months, P less than 0.01). However, apo AI and apo AII remained unchanged. Atherogenic indices of (TC--HDL-C)/ HDL-C, LDL-C/HDL-C, and apo B/Apo AI ratios were significantly (P less than 0.01) reduced after treatment. No significant changes were observed in lipoprotein lipase, hepatic TG lipase, and lecithin: cholesterol acyltransferase (LCAT) activities. Simvastatin was well tolerated and no critical side effects were noted in the eight-month study period. These data indicate that simvastatin, even at a low dose of 2.5 to 5 mg daily, causes consistent reductions in serum TC, LDL-C, apo B, and TG, and a rise in HDL-C and antiatherogenic lipoproteins.
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PMID:Low-dose effect of simvastatin (MK-733) on serum lipids, lipoproteins, and apolipoproteins in patients with hypercholesterolemia. 273 71

The effects of alcohol intake on serum lipids and lipoproteins depend on the dose and mode of alcohol intake, individual susceptibility, genetic variables, and dietary factors. Therefore the changes of lipoprotein pattern are different among moderate and heavy drinkers. Moderate intake of alcohol increases the concentrations of apolipoproteins (apo) AI, apo AII, and high-density lipoprotein subfraction (HDL3) in plasma without any effects on other lipoproteins. If alcohol intake exceeds 60 to 80 gm per day, the synthesis of very low-density lipoprotein (VLDL) particles is stimulated. Even short-term use of alcohol stimulates lipoprotein lipase (LPL) activity in adipose tissue, and consequently the concentration of VLDL in plasma stays normal or is even subnormal. If alcohol intake continues in excessive amounts, the increased transport rate of VLDL particles as a result of high LPL activity results in the up regulation of HDL2. This is clearly evident in chronic alcoholics. Low or subnormal low-density lipoprotein (LDL) levels are another characteristic of the lipoprotein pattern in chronic alcoholics. The increase of HDL (HDL2) and reduction of LDL levels could well explain the reduced risk of coronary heart disease in chronic alcoholics, whereas the causal factors remain open among moderate drinkers.
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PMID:Alcohol-induced changes in serum lipoproteins and in their metabolism. 354 60

Gemfibrozil is a potent lipid regulating drug whose major effects are to increase plasma high density lipoproteins (HDL) and to decrease plasma triglycerides (TG) in a wide variety of primary and secondary dyslipoproteinemias. Its mechanism of action is not clear. Six patients with primary familial endogenous hypertriglyceridemia with fasting chylomicronemia (type V lipoprotein phenotype) with concurrent subnormal HDL cholesterol levels (HDL deficiency) were treated initially by diet and once stabilized, were given gemfibrozil (1,200 mg/d). Each patient was admitted to the Clinical Research Center with metabolic kitchen facilities, for investigation of HDL and TG metabolism immediately before and after 8 wk of gemfibrozil treatment. Gemfibrozil significantly increased plasma HDL cholesterol, apolipoprotein (apo) AI, and apo AII by 36%, 29%, and 38% from base line, respectively. Plasma TG decreased by 54%. Kinetics of apo AI and apo AII metabolism were assessed by analysis of the specific radioactivity decay curves after injection of autologous HDL labeled with 125I. Gemfibrozil increased synthetic rates of apo AI and apo AII by 27% and 34%, respectively, without changing the fractional catabolic rates. Stimulation of apo AI and apo AII synthesis by gemfibrozil was associated with the appearance in plasma of smaller (and heavier) HDL particles as assessed by gradient gel electrophoresis and HDL composition. Postheparin extra-hepatic lipoprotein lipase activity increased significantly by 25% after gemfibrozil, and was associated with the appearance in plasma of smaller very low density lipoprotein particles whose apo CIII:CII ratio was decreased. These data suggest that gemfibrozil increases plasma HDL levels by stimulating their synthesis. Increased transport (turnover) of HDL induced by gemfibrozil may be significant in increasing tissue cholesterol removal in these patients.
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PMID:Mechanism of action of gemfibrozil on lipoprotein metabolism. 392 42

Plasma high-density lipoproteins (HDL) and their major proteins--apolipoprotein (apo) AI and apo AII--are subnormal in most patients with familial hypertriglyceridemia. However, the pathophysiology of low-plasma apo AI and apo AII is unclear. The kinetic parameters (turnover) of HDL apo AI and apo AII were studied in six lean patients with primary HDL deficiency associated with familial hypertriglyceridemia and five normolipidemic controls. Autologous 125I labeled HDL were injected intravenously (IV; 25 microCi) and blood samples drawn ten minutes after the injection and periodically thereafter for 12 days. Urine samples were collected daily and their radioactivity measured. Kinetic parameters were calculated from the area under the decay curve using three exponentials. Mean plasma apo AI and apo AII were significantly lower (P less than 0.001) in patients than normals (70.4 +/- 2.7 v 106.9 +/- 7.0; 24.2 +/- 1.6 v 39.2 +/- 0.9 mg/dL, respectively). The mean fractional catabolic rates (FCR) obtained from plasma 125I-HDL, apo AI, apo AII radioactivity decay curves and by Berson and Yalow's method (urine/plasma radioactivity ratios) were significantly greater (P less than 0.05) in patients than in controls (0.387 v 0.299; 0.391 v 0.309; 0.361 v 0.275; 0.272 v 0.207/d; respectively). The mean synthetic rates (SR) of apo AI and apo AII were significantly lower in patients than in controls (11.12 v 14.17 mg/kg body weight/d, P less than 0.05; 3.53 v 4.68 mg/kg body weight/d, P less than 0.05, respectively). In vitro lipolysis of triglyceride (TG) rich lipoproteins by bovine lipoprotein lipase, and measurement of hepatic TG lipase and lipoprotein lipase in postheparin plasma were similar in patients and controls, indicating no abnormality in these factors that are linked to HDL and TG catabolism. However, a significant positive correlation between hepatic TG lipase and the FCR of apo AI and apo AII was found. The data suggest that in this series of patients with HDL deficiency the low plasma HDL-cholesterol, apo AI, and apo AII levels resulted from decreased synthesis and an increased fractional catabolic rate of apo AI and apo AII, the major proteins of HDL.
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PMID:Apolipoprotein AI and AII metabolism in patients with primary high-density lipoprotein deficiency associated with familial hypertriglyceridemia. 392 10

In order to gain further insight into the relationship between high-density lipoprotein (HDL) metabolism and plasma triglyceride transport, measurements were made of HDL cholesterol concentration, apoprotein (apo) AI and AII metabolism, very-low-density-lipoprotein (VLDL) apo B metabolism, and heparin-elutable adipose tissue lipoprotein lipase (LPL) activity in seventeen subjects with a wide range of plasma triglyceride concentrations (0.8-25 mmol/l). The fractional catabolic rate (FCR) of VLDL apo B was directly related to LPL activity (r = +0.80), providing evidence that the activity of the enzyme in adipose tissue is a determinant of the rate of lipolysis of VLDL in man. HDL cholesterol concentration was a positive function of both VLDL apo B FCR (r = +0.74) and LPL activity, a finding consistent with previous evidence for the origin of a proportion of HDL cholesterol from 'surface remnants' liberated during VLDL catabolism. THe FCRs of both apo AI and apo AII were inversely related to VLDL apo B FCR (AI, r = -0.52; AII, r = -0.69) and to LPL activity. The synthetic rate of ap AII, but not that of apo AI, was positively correlated with VLDL apo B synthesis (r = +0.7 1). Thus, the metabolism of the major proteins of HDl in man appears to be closely associated with VLDL metabolism.
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PMID:Relationships between the metabolism of high-density and very-low-density lipoproteins in man: studies of apolipoprotein kinetics and adipose tissue lipoprotein lipase activity. 680 82

A decreased level of HDL cholesterol (HDL-C) is the most common lipoprotein abnormality seen in people with premature coronary artery disease (CAD). In many cases, HDL-C reduction in patients with CAD may be the result of increased apo B-containing lipoprotein production by the liver with secondary hypoalphalipoproteinemia. Primary hypoalphalipoproteinemia is seen in approximately 4% of people with CAD. We report findings in four subjects with severe familial HDL deficiency (HDL-C << 5th percentile for age and sex; 0.08 to 0.38 mmol/L) in three French-Canadian kindreds with autosomal codominant inheritance. By inclusion criteria, all four subjects had normal fasting triglycerides and none were diabetic. HDL particle size by gradient gel electrophoresis revealed small HDL particles (estimated Stokes' diameter, 8.14 to 8.30 nm). Apo AI analysis by polyacrylamide gel electrophoresis and use of isoelectrofocusing gels in affected subjects revealed normal molecular weight (28.3 kD) and normal isoelectrofocusing point but a relative increase in proapoliprotein AI, with near-normal levels of proapolipoprotein AI in plasma, suggesting normal secretion of apo AI. Quantitative Southern blot analysis of the apo AI-CIII-AIV gene cluster reveals no gene rearrangements or allele deletion. Haplotypes of the apo AI gene, determined by use of the restriction enzymes Pst I, Xmn I, and Sst I and of the apo AII gene by use of the enzyme Msp I, did not reveal segregation of the low HDL-C trait with either the apo AI or the AII gene. Sequence analysis of the promoter region of the apo AI gene reveals heterozygosity for guanine-to-adenine substitution at position 76 in two kindreds with no evidence of segregation with the low HDL trait. None of the patients had mutations of the lipoprotein lipase gene common in subjects of French-Canadian descent. Haplotype analysis of the lipoprotein lipase gene did not show segregation with the low HDL trait. Plasma lecithin: cholesterol acyltransferase (LCAT) activity was found to be within normal levels in affected subjects and in nonaffected first-degree relatives. None of the affected subjects had clinical manifestations of Tangier disease. Two of the four cases examined, both men, had severe CAD and had undergone revascularization procedures. The third is a younger brother of one of these probands and the fourth is a 30-year-old woman, and both were free of clinical CAD. However, in none of the families did the low HDL trait unequivocally cosegregate with CAD.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Severe familial HDL deficiency in French-Canadian kindreds. Clinical, biochemical, and molecular characterization. 762 90

Epidemiological studies have elucidated that diabetes mellitus (DM) is one of the risk factors of coronary heart disease and that DM often accompanies dyslipidemia. Dyslipidemia in DM can be classified as either quantitative or qualitative. Although dyslipdemia in DM is affected by the type of DM and glycemic conditions, the characteristics of dyslipidemia in DM, especially in NIDDM are the increase in triglycerides accompanied by the decrease in HDL-cholesterol level. Recently, new commercial kits for measurement of atherogenic lipoproteins which increase in DM are clinically available. The usefulness of these kits in DM was reviewed. Polyacrylamide electrophoresis can detect IDL and Lp(a) qualitatively. It has also become possible to estimate Lp(a) quantitatively by ELISA, TIA and LIA methods. Remnant lipoprotein can be measured in the fraction unbound to anti-apo A1 and anti-apo B100 antibodies by immunoaffinity gel analysis. Apoproteins, apoprotein E phenotype, post-heparin lipoprotein lipase, and Lp AI (HDL with apo AI and without apo AII) can be measured by the commercially available kits. Modified LDLs (glycated, oxidative) increase in DM, but their measurements remain complicated at the moment. Analysis of plasma fatty acids by gaschromatography is useful for dietary assessment. The measurement of these new markers seems to be useful to assess the extent of atherogenic risk in DM.
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PMID:[Plasma fatty acids, lipids, lipoprotein and macroangiopathy]. 778 61

The effects of 20 days bed rest (BR) on serum lipids and lipoprotein concentrations were investigated in 23 healthy young subjects (13 males and 10 females, aged 19 to 25 yr.). After 20 days BR, VO2max was reduced in both genders, but body composition did not change. The ratio of glucose area to insulin area during an oral glucose tolerance test decreased gradually throughout BR, which suggested a decrease in insulin sensitivity. Estimated changes in plasma volume from the beginning of BR were largest at day 3 of BR (-9.1% in females and -3.4% in males) and seemed to return the initial level at the end of BR in both genders. The increase in serum triglycerides and the decrease in high density lipoprotein (HDL) cholesterol, and apolipoprotein AI were observed in both genders during BR. In a smaller study of 4 males and 5 females, 20 days BR was associated with a decrease in HDL, cholesterol, a decrease in apolipoprotein AI and apolipoprotein AII, decrease in a plasma postheparin lipoprotein lipase activity and an increase in very low density lipoprotein triglyceride. Overall, the data suggested that the decrease in lipoprotein lipase activity and insulin sensitivity may contribute to the impairment in HDL metabolism.
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PMID:The effects of 20 days bed rest on serum lipids and lipoprotein concentrations in healthy young subjects. 1154 Nov 83

Fibrates regulates not only plasma lipid metabolism but vascular biology by activating nuclear receptor peroxisome proliferating activated alpha (PPAR alpha). Major effects on plasma lipid levels are lowering plasma triglyceride level and elevating plasma HDL cholesterol level, whereas its effect on plasma cholesterol level is moderate compared to HMG-CoA reductase inhibitor. As a mechanism for its effects on plasma lipid levels and atherosclerosis, recent studies reported that fibrates activates various genes involved in metabolism of remnants and HDL such as lipoprotein lipase, apo AI, apo AII, and apo CIII genes through the interaction with PPAR alpha, lowering atherogenic lipoproteins and elevating anti-atherogenic lipoproteins. Furthermore, fibrates may influence the process of atherosclerosis by modifying inflammatory process in vascular wall. Recent clinical studies demonstrated that fibrates significantly reduce cardiovascular events in patients with either hypertriglyceridemia or low HDL cholesterol level.
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PMID:[Fibrates]. 1203

Apolipoprotein (apo) A-II has been biochemically and genetically linked to familial combined hyperlipidemia. Human ApoA-II transgenic mice and peroxisome proliferator-activated receptor alpha (PPARalpha)-deficient mice share some similar phenotypic characteristics. The aim of this study was to determine whether a fibrate-induced PPARalpha activation corrects the combined hyperlipidemia present in human apoA-II transgenic mice. ApoA-II transgenic mice were treated with fenofibrate (250 mg/kg) for 13 days. After this period, they presented a remarkable 8-fold increase in plasma triglycerides. This was concomitant with a 4-fold increase in non-high-density lipoprotein (non-HDL) cholesterol, a quantitatively similar decrease in HDL cholesterol and a severe reduction in mouse plasma apoA-I and apoA-II. Fenofibrate stimulated liver fatty acid beta-oxidation, increased the transcriptional expression of carnitine palmitoyltransferase 1 and phospholipid transfer protein, and decreased expression of apoA-I and apoC-III. However, very-low-density lipoprotein (VLDL)-triglyceride production and lipoprotein lipase (LPL) activities and the expression of other PPARalpha target genes were similar in mice treated with vehicle and fenofibrate. Further, fenofibrate-treated mice presented decreased in vivo [3H]VLDL catabolism and decreased VLDL-triglyceride hydrolysis by exogenous LPL. Therefore, the paradoxical enhancement of hyperlipidemia in fenofibrate-treated apoA-II transgenic mice is mainly due to decreased VLDL catabolism and, also, to a partial impairment in PPARalpha-signaling.
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PMID:Paradoxical exacerbation of combined hyperlipidemia in human apolipoprotein A-II transgenic mice treated with fenofibrate. 1622 89


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