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: UMLS:C0020473 (hyperlipidemia)
15,891 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The aim was to identify genetic determinants for the development of hyperlipidemia and/or atherosclerosis. The present set of studies demonstrates for the first time the clinical expression (phenotype) of a newly discovered monogenic disorder named Familial Defective Apolipoprotein B-100 (FDB). FDB is caused by a G to A mutation in the binding protein (apolipoprotein B-100) for the cholesterol-rich low density lipoprotein (LDL), such that the affinity of LDL to the LDL receptor is severely reduced. In all 135 individuals with FDB from 56 families and 8 different countries, including Denmark, are described. On average, the effect of the FDB mutation was to increase plasma and LDL cholesterol in both men and women by about 3 mmol/l; at age 55 the average plasma cholesterol of men and women with FDB was 9.4 mmol/l and 8.9 mmol/l, respectively. A sharp rise in frequency of coronary artery disease as a function of age in both FDB males and females was comparable to that found in Familial Hypercholesterolemia (FH). At the age of 60, about 70% of both men and women with FDB had coronary artery disease; at the same age approximately 40% had tendon xanthomas, and 35% had arcus corneae, irrespective of gender. Surprisingly, the frequencies of arcus corneae were not strikingly higher than those found in the general population sample from the Copenhagen City Heart Study. Only few patients with FDB had xanthelasmas. Finally, the frequency of this mutation was estimated at 1/500-1/700 in the general population, which is equivalent to that of clinical FH. All in all the results suggest FDB to be a severe genetic disorder with early penetrance, associated with substantial elevations in plasma and LDL cholesterol and with an increased frequency of premature coronary artery disease and of tendon xanthomas. For comparison, a number of common polymorphisms in the 5'-flanking region of the insulin gene, in the apoB gene and in the apoAI-CIII-AIV gene cluster, associated with minor effects on hyperlipidemia and/or cardiovascular disease are also examined.
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PMID:Rare and common mutations in hyperlipidemia and atherosclerosis. With special reference to familial defective apolipoprotein B-100. 765 81

The effects of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors on the metabolism of apolipoprotein (apo) B-containing lipoproteins appear to differ according to the predominant lipoprotein profiles present and the condition being treated. In familial hypercholesterolemia, with isolated low density lipoprotein (LDL) elevations, the LDL-apoB elimination rate is increased by up-regulated LDL-receptors. In familial combined hyperlipidemia where very low density lipoprotein (VLDL) and LDL both may be increased and enhanced production of LDL-apoB may be present, HMG-CoA reductase inhibitors seem to diminish increased LDL-apoB production. The drug-induced decreases in LDL-apoB production could be due to decreased production of precursor VLDL-apoB or due to decreased conversion of VLDL-apoB to LDL-apoB after enhanced removal of VLDL by up-regulated LDL-receptors. To distinguish between these possibilities, we assessed the effects of HMG-CoA reductase inhibitors in another condition in which there is both apoB overproduction and accumulation of VLDL and LDL in plasma, the nephrotic syndrome. We used endogenous labeling of apoB with [13C]leucine and a multicompartmental model to calculate the metabolic parameters of apoB-containing lipoproteins. Only subjects with focal segmental glomerular sclerosis (FSGS) were included, as FSGS is a chronic, very slowly progressive form of nephrotic syndrome. A double-blind, randomized, placebo-controlled, crossover design was used. Treatment periods of 6 weeks were separated by a 2-week washout period. Of the four men studied, three had high triglyceride levels and four had high cholesterol levels. Lovastatin (20 mg/day) significantly decreased cholesterol (27.6 +/- 6%), LDL-cholesterol (27.6 +/- 9%) and plasma apoB (17.9 +/- 2.9%) (P < 0.01 for all). During the placebo period, calculation of kinetic parameters revealed VLDL-, intermediate density lipoprotein (IDL)-, and LDL-apoB overproduction and decreased VLDL-apoB fractional catabolic rate. Lovastatin significantly decreased LDL-apoB production rate in all cases (34.1 +/- 14%, P = 0.03). The decreased LDL-apoB was mainly due to a channelling of LDL precursors away from conversion to LDL (conversion of VLDL to LDL decreased from 80.6 +/- 8.3% to 55.9 +/- 17.2%, P = 0.05). Thus, lovastatin decreased LDL-cholesterol in nephrotic subjects mainly by inhibiting LDL-apoB production from VLDL.
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PMID:Physiologic mechanisms of action of lovastatin in nephrotic syndrome. 770 43

Familial xanthomatous hypercholesterolemia is a metabolic disorder associated with high LDL levels attributed to a familial defect in LDL receptor activity. We have previously shown that hyperlipoproteinemia of WHHL rabbits, considered to be a model for heritable hypercholesterolemia, was at least partly of exogenous origin. We have though studied retinyl palmitate (RP) levels 12 h after a standardized mixed meal as a simple test to detect abnormalities of intestinal-derived lipoprotein clearance in 22 familial hypercholesterolemic patients with xanthomatosis (13 of them treated by simvastatin, an HMGCoA reductase inhibitor, and 9 not treated), as compared to a control group (n = 12). Total and LDL cholesterol, plasma triglyceride and apo B levels were significantly higher in patients when compared to controls. Mean RP levels appeared higher in familial hypercholesterolemic patients, when compared to controls, with 6 among 22 patients showing clearly high vitamin A levels and 4 borderline values, whereas high triglyceride levels (> 2 g/l) were detected in only 1 patient. No patients within the group with high vitamin A levels showed an apo E2/E2 phenotype. Vitamin A levels correlated with plasma triglycerides in the whole group of subjects (r = 0.50, p < 0.05). No difference was observed in vitamin A distribution between treated and untreated hypercholesterolemic patients. Our results indicate that the clearance of RP-labeled intestinal lipoproteins is delayed in some xanthomatous familial hypercholesterolemic patients as compared with that of controls. These findings suggest that familial xanthomatous hypercholesterolemia may be heterogenous concerning physiopathological mechanisms inducing hyperlipidemia.
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PMID:Familial xanthomatous hypercholesterolemia: abnormal exogenous lipid metabolism evidenced by the vitamin A test. 771 Feb 66

Significant risk factors for premature coronary heart disease include: (1) family history, (2) elevated low density lipoprotein (LDL) cholesterol level > or = 160 mg/dl, l, (3) decreased high density lipoprotein (HDL) cholesterol level < 35 mg/dl, l, (4) cigarette smoking, (5) high blood pressure and (6) diabetes mellitus. All of these risk factors are common in patients with premature heart disease. Common familial lipid disorders associated with premature heart disease include familial lipoprotein(a) excess, familial dyslipidemia (elevated triglycerides and decreased HDL cholesterol), familial combined hyperlipidemia (elevations of LDL cholesterol and triglycerides, and often decreased HDL cholesterol), familial hypoapobetalipoproteinemia (elevated apolipoprotein B levels), familial hypoalphalipoproteinemia (low HDL cholesterol levels), and familial hypercholesterolemia (elevated LDL cholesterol levels). All these disorders have been characterized using age and gender specific 90th and 10th percentile values from the normal population. The diagnosis and potential management of these disorders is reviewed.
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PMID:Familial lipoprotein disorders and premature coronary artery disease. 780 28

The discovery and production of HMGCoA reductase inhibitor and the fundamental research work of the LDL receptor unraveled a receptor-mediated cholesterol homeostasis. HMGCoA reductase inhibitors are the most commonly prescribed class of lipid-lowering drugs in many countries. The decrease of the intracellular cholesterol caused by the inhibitor induces the compensatory increase of LDL receptor protein at liver plasma membrane. The increased receptor promotes LDL catabolism and results in decrease of plasma LDL. Serious side effects involving the liver or muscle are rare. But the risk of myopathy is increased when the drug is used with other hypolipidemic agents. A principle of the treatment of hyperlipidemia, including secondary one associated with diabetes mellitus and renal disease, by HMGCoA reductase is discussed in this review.
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PMID:[HMG-CoA reductase inhibitor for therapy of patients with hyperlipoproteinemia ]. 785 22

Relatively little is known about the biological mechanisms by which lipoproteins promote atherogenesis. It has, however, been shown that structural modification of low density lipoprotein (LDL), such as by oxidation, results in their uptake and degradation by intimal macrophages and consequently leads to formation of lipid-rich atherosclerotic lesions. The aim of the present investigation was to study the influence of dietary intake of fat, lipoprotein lipid composition, smoking and gender on macrophage degradation of LDL before and after oxidation. The study group consisted of 48 males and 56 females with hyperlipidemia taking part in the open prerandomization phase of the Probucol Quantitative Regression Swedish Trial (PQRST). Analysis including lipoprotein determinations, dietary and smoking habit interviews, LDL degradation by macrophages, LDL receptor binding and LDL thiobarbituric acid reactive substance (TBARS) levels before and after copper ion-induced oxidation was done during the pre-andomization phase of the study. Increased plasma and very low density lipoprotein (VLDL) triglyceride levels were associated with an increased macrophage degradation of native LDL, whereas no such association was found after oxidation of LDL. The dietary intake of polyunsaturated fatty acids (PUFA) was also inversely related to the degradation of native LDL by macrophages, but increased the rate at which oxidized LDL was degraded. Smoking and gender did not influence the rate of macrophage degradation of native or oxidized LDL. It is concluded that hypertriglyceridemia is associated with an increased macrophage degradation of LDL. This may represent a mechanism by which hypertriglyceridemia promotes atherosclerosis.
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PMID:Influence of lipoprotein lipids, dietary fat and smoking on macrophage degradation of native and oxidized low density lipoprotein. 785 66

Combined hyperlipidaemia and the presence of small and dense LDL particles in the circulation are associated with an increased risk of myocardial infarction. The effect of pravastatin on plasma lipoproteins and on LDL size has been evaluated in a single-blind, randomised, placebo-controlled study in 24 patients with combined hyperlipidaemia; 12 patients on pravastatin and 12 on placebo. After 16 weeks on pravastatin, plasma total (-15%) and LDL (-23%) cholesterol and apo B (-13%) levels were significantly reduced and apo AI (+6%) had increased. LDL size (measured by gradient gel electrophoresis) had not changed. No adverse effect was observed. The study suggests that, in combined hyperlipidaemia, LDL size is not affected by variation in LDL receptor activity.
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PMID:Pravastatin treatment in combined hyperlipidaemia. Effect on plasma lipoprotein levels and size. 807 May 2

The pregnancy and delivery of a subject with homozygous familial hypercholesterolemia (FH) and coronary artery disease (CAD) were monitored closely for signs of maternal and fetal distress. Biweekly treatment with low-density lipoprotein (LDL) apheresis using dextran-sulfate cellulose columns was continued throughout the pregnancy, and lipid and lipoprotein levels were evaluated. During the course of the pregnancy and delivery, no signs of maternal coronary insufficiency developed. Serial ultrasonographic measurements of fetal growth indices and the blood flow velocity waveforms (FVWs) of the uterine and umbilical artery did not reveal any sign of fetal growth retardation or insufficiency of the uteroplacental circulation, respectively. During pregnancy, time-averaged concentrations of serum total cholesterol (TC), LDL cholesterol (LDL-C), apolipoprotein (apo) B, and lipoprotein(a) [Lp(a)] showed a gradual decline. Notwithstanding LDL apheresis, a gradual twofold increase of serum triglyceride (TG) levels was found. In the second and third trimester, high-density lipoprotein cholesterol (HDL-C) levels showed a 55% increase that coincided with a 75% reduction in hepatic lipase activity in postheparin plasma, normalizing after parturition. After delivery, lp(a) levels showed an almost twofold increase, which could not be explained by the interruption of LDL apheresis alone, and may be caused by changes in gonadal steroids. Histologic examination of the placenta and the umbilical arteries revealed no atherosclerotic changes, infarctions, or lipid deposits. In general, long-term LDL apheresis in homozygous FH can delay the onset and complications of severe CAD. In case of a pregnancy, LDL apheresis seems feasible and should be continued during the pregnancy to prevent superimposed hyperlipidemia and placental insufficiency.
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PMID:Pregnancy in a patient with homozygous familial hypercholesterolemia treated with long-term low-density lipoprotein apheresis. 808 91

The lipoprotein(a) (Lp(a) concentrations in serum were measured by an ELISA technique in 53 subjects affected by familial combined hyperlipidemia (FCHL) and in 347 healthy individuals. Lp(a) geometric means did not differ significantly between the two groups despite the different distributions. In hyperlipidemic subjects, the distribution was markedly shifted to the right (median 17 mg/dl) while in controls it was highly skewed to the left (median = 11 mg/dl). In FCHL, Lp(a) serum levels did not differ between patients with or without coronary heart disease (CHD). It was concluded that, differently from familial hypercholesterolemia (FH), in FCHL Lp(a) may not be elevated in comparison with an adequate control population.
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PMID:Lipoprotein(a) serum concentration in familial combined hyperlipidemia. 814 58

Large-scale and systemic epidemiological, pathological and experimental studies emphasized and documented the childhood origin of atherosclerosis. There is increasing consensus that lipid levels in children to a large extent determine the rate of coronary artery disease (CAD) in the adult population. Minimal sudanophilic intimal deposits, and the presence of intracellular and extracellular lipid, and a slight increase in interstitial ground substance in 3 years of age or older patients are found. In the Bogalusa Hearth Study aortic fatty streaks were strongly related the antemortem levels of both total cholesterol and low-density lipoprotein cholesterol (LDL-C) independent of race, sex, and age, and were negatively correlated with the ratio of high-density lipoprotein (HDL-C) to low-density plus very-low-density lipoprotein cholesterol (LDL-C+VLDL-C). The potential for primary prevention is real and the strongest piece of evidence for its is the remarkable trend in CHD mortality rates in recent times, rapidly downward in many western countries. A number of factors influence plasma levels of lipid and lipoproteins in newborn, in infants, in children and adolescents and their relevance as possible predictors of adult coronary artery disease. They are certain inherited disorders of dyslipoproteinemia (familial hypercholesterolemia, familial combined hyperlipidemia, hyperapobetalipoproteinemia, and hypoalphalipoproteinemia) and secondary causes of hyperlipidemia (congenital biliary atresia, glycogen storage diseases, hypothyroidism, diabetes mellitus and nephrotic syndrome, etc).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Atherosclerosis and juvenile dyslipidemias]. 818 5


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