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)

Several characteristics of the rabbit make it an excellent model for the study of lipoprotein metabolism and atherosclerosis. New Zealand White (NZW) rabbits have low plasma total cholesterol concentrations, high cholesteryl ester transfer protein activity, low hepatic lipase (HL) activity, and lack an analogue of human apolipoprotein (apo) A-II, providing a unique system in which to assess the effects of human transgenes on plasma lipoproteins and atherosclerosis susceptibility. Additionally, rabbit models of human lipoprotein disorders, such as the Watanabe Heritable Hyperlipidemic (WHHL) and St. Thomas' Hospital strains, models of familial hypercholesterolemia and familial combined hyperlipidemia, respectively, allow for the assessment of candidate genes for potential use in the treatment of dyslipoproteinemic patients. To date, transgenes for human apo(a), apoA-I, apoB, apoE2, apoE3, HL, and lecithin:cholesterol acyltransferase (LCAT), as well as for rabbit apolipoprotein B mRNA-editing enzyme catalytic poly-peptide 1 (APOBEC-1), have been expressed in NZW rabbits, whereas only those for human apoA-I and LCAT have been introduced into the WHHL background. All of these transgenes have been shown to have significant effects on plasma lipoprotein concentrations. In both NZW and WHHL rabbits, human apoA-I expression was associated with a significant reduction in the extent of aortic atherosclerosis, which was similarly the case for LCAT in rabbits having at least one functional LDL receptor allele. Conversely, expression of apoE2 in NZW rabbits caused increased susceptibility to atherosclerosis. These studies provide new insights into the mechanisms responsible for the development of atherosclerosis, emphasizing the strength of the rabbit model in cardiovascular disease research.
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PMID:Transgenic rabbits as models for atherosclerosis research. 1006 24

We investigated the mechanisms that lead to combined hyperlipidemia in transgenic mice that overexpress human apolipoprotein (apo) A-II (line 11.1). The 11.1 transgenic mice develop pronounced hypertriglyceridemia, and a moderate increase in free fatty acid (FFA) and plasma cholesterol, especially when fed a high-fat/high-cholesterol diet. Post-heparin plasma lipoprotein lipase and hepatic lipase activities (using artificial or natural autologous substrates), the decay of plasma triglycerides with fasting, and the fractional catabolic rate of the radiolabeled VLDL-triglyceride (both fasting and postprandial) were similar in 11. 1 transgenic mice and in control mice. In contrast, a 2.5-fold increase in hepatic VLDL-triglyceride production was observed in 11. 1 transgenic mice in a period of 2 h in which blood lipolysis was inhibited. This increased synthesis of hepatic VLDL-triglyceride used preformed FFA rather than FFA of de novo hepatic synthesis. The 11.1 transgenic mice also presented reduced epididymal/parametrial white adipose tissue weight (1.5-fold), increased rate of epididymal/parametrial hormone-sensitive lipase-mediated lipolysis (1.2-fold) and an increase in cholesterol and, especially, in triglyceride liver content, suggesting an enhanced mobilization of fat as the source of preformed FFA reaching the liver. Increased plasma FFA was reverted by insulin, demonstrating that 11.1 transgenic mice are not insulin resistant. We conclude that the overexpression of human apoA-II in transgenic mice induces combined hyperlipidemia through an increase in VLDL production. These mice will be useful in the study of molecular mechanisms that regulate the overproduction of VLDL, a situation of major pathophysiological interest since it is the basic mechanism underlying familial combined hyperlipidemia.
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PMID:Increased production of very-low-density lipoproteins in transgenic mice overexpressing human apolipoprotein A-II and fed with a high-fat diet. 1108 33

The association of postprandial hyperlipidemia, small and dense LDL particles and low HDL cholesterol levels is a major cardiovascular risk factor, highly prevalent in insulin resistant and diabetic patients. Several recent epidemiological studies have demonstrated that an abnormal increase in the postprandial triglyceride levels is an independent cardiovascular risk factor, independent from fasting triglyceride levels. A decreased clearance of postprandial triglycerides is related to an abnormal intravascular lipoprotein metabolism, most of the time secondary to an insulin resistant state and genetic factors. This abnormal lipoprotein metabolism also induces a redistribution of LDL particles towards small and dense particles and a decrease in the HDL cholesterol levels. Small, dense LDL are associated with a 3 fold increase in the risk of ischemic heart disease, but does not remain a significant risk factor after adjustment for triglyceride levels. Decreased HDL cholesterol and apolipoprotein A-I levels are strong cardiovascular risk factors, which does not seem to be better assessed with the assay of various HDL sub-fractions (HDL(2) et HDL(3), LpA-I et LpA-I: A-II.).
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PMID:[Postprandial hyperlipidemia, small and dense LDL, HDL sub-fractions]. 1143 75

Plasma glutathione peroxidase (PGPx) and apolipoproteins A-I, A-II, and B-100 reduce phosphatidylcholine hydroperoxide (PC-OOH) to its hydroxide (PC-OH). To elucidate the relative importance of the reduction pathways we developed a simple assay for measuring total PC-OOH-reducing activity. Human plasma was incubated with 1-palmitoyl-2-linoleoyl-phosphatidylcholine hydroperoxide and the time-dependent reduction was confirmed by its hydroxide formation, measured by reversed-phase high performance liquid chromatography. We determined the PC-OOH reducing activity in blood plasma of healthy men and women as 119 +/- 7 (n = 13, aged 27 to 45) and 101 +/- 4 microM/h (n = 5, aged 24 to 30), respectively. In addition, we also measured PC-OOH-reducing activity in the plasma of 53 pregnant women since they usually show hyperlipidemia or hyper-apolipoproteinemia. The average rate of PC-OOH reduction was 101 +/- 34 microM/hr. The PC-OOH-reducing activity was not affected by the addition of iodoacetamide, an inhibitor of PGPx, suggesting that the activity is due to apolipoproteins. A significant correlation between plasma reducing activity with apolipoprotein B-100 was observed (r = 0.290), but not with apolipoprotein A-I (r = 0.118). In pre-eclamptic patients, about an 8% decrease in plasma PC-OOH-reducing activity was observed as compared to the normal pregnancy group, although the decrease was not statistically significant.
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PMID:Plasma phosphatidylcholine hydroperoxide-reducing activity in pregnant women. 1203 Apr 43

In this study, we present clinical feature of a novel case with homozygous apolipoprotein (apo) E5. The patient was a 53-year-old Japanese woman. She was from a small island off the coast of Kagoshima Prefecture, Japan. Her parents were first degree cousins. No corneal opacification, xanthomatosis, lymphadenopathy, or hepatosplenomegaly was observed. There have been no signs of clinically overt atherosclerosis to date. Her serum total cholesterol, triglycerides (TG) and high-density lipoprotein (HDL)-cholesterol levels were 11.6, 6.1 and 1.2 mmol/l, respectively, and apo A-I, A-II, B, C-II, C-III and E levels were 121, 34.8, 269, 10.4, 25.7 and 10.3 mg/dl, respectively. Serum lipoprotein profile analyzed by agarose gel electrophoresis and differential staining revealed markedly increased cholesterol and TG in both beta and prebeta-migrated lipoproteins, whereas alpha-migrated lipoprotein showed decreased cholesterol. Her apo E isoform analyzed by isoelectric focusing (IEF) was found to be homozygous apo E5. Polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis of her apo E and lipoprotein lipase (LPL) genes revealed that she had a homozygous apo E (Glu3-->Lys) and heterozygous LPL variant Ser447 to Ter. Her son and daughter, both of whom had hyperlipidemia, were found to have apo E3/5 phenotype. Direct sequencing analysis of her apo E gene confirmed a homozygous one nucleotide change: G to A at nucleotide position of 2836 in the exon 3, resulting in Glu3-->Lys mutation. This is the first report of lipids and lipoprotein profiles in patients with homozygous apo E5 (Glu3-->Lys).
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PMID:A case of hyperlipidemia with homozygous apolipoprotein E5 (Glu3-->Lys). 1206 56

Low levels of high-density lipoproteins cholesterol (HDL-C) as well as impaired postprandial lipemia are known to be associated with the increased risk for coronary artery disease (CAD) in patients with type 2 diabetes mellitus (type 2 DM). HDL are heterogeneous in size and apolipoprotein composition. Recent evidence indicates that among the 2 major HDL subclasses, those without apolipoprotein A-II (LpA-I) are more antiatherogenic compared with those with apoA-II (LpA-I:A-II). Cilostazol, a novel selective phosphodiesterase type III inhibitor, has been shown to inhibit platelet activation and is also a potent vasodilator. Additionally, cilostazol has been shown to modulate lipoprotein profiles by raising HDL-C and lowering plasma triglyceride (TG) levels. The present study investigated the effect of cilostazol on HDL composition (LpA-I and LpA-I:A-II levels) and postprandial lipemia in patients with type 2 DM. Seventeen patients were given cilostazol 200 mg twice daily for 12 weeks. At weeks 0 and 12, fat tolerance tests (30 g/m(2)) were performed to assess postprandial lipemia. Plasma TG and remnant-like lipoprotein particles cholesterol (RLP-C) were significantly decreased by 17% and 26%, respectively (P <.05), and HDL-C was significantly increased by 14% (P <.01). LpA-I was significantly increased by 23% (P <.01) from the mean value of 45 mg/dL to 55 mg/dL. In contrast, LpA-I:A-II remained unchanged, resulting in significantly increased %LpA-I (apoA-I on LpA-I/total apoA-I x 100) from 35% to 40% (P <.01). Areas under the curve for TG and RLP-C after the fat meal were both nonsignificantly decreased by 17%. Patients with higher plasma TG levels had a greater benefit from the treatment with cilostazol as revealed by fasting TG levels and fat tolerance tests. HDL-C responses to cilostazol were independent of baseline plasma TG levels or percentage changes in TG, indicating that the underlying mechanisms for raising HDL and reducing TG levels are distinct. In conclusion, cilostazol selectively increased LpA-I, thus favorably altering HDL towards a more antiatherogenic composition. This finding, together with the improved postprandial lipemia, indicates that cilostazol has a potent antiatherogenic function by modulating HDL and remnant metabolism in patients with type 2 DM.
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PMID:Cilostazol, a potent phosphodiesterase type III inhibitor, selectively increases antiatherogenic high-density lipoprotein subclass LpA-I and improves postprandial lipemia in patients with type 2 diabetes mellitus. 1237 Aug 57

A remarkable reduction of plasma concentrations of high-density lipoproteins (HDL), especially of the HDL(2) subfraction, is one of the typical lipoprotein alterations found in patients with familial combined hyperlipidemia (FCHL). Fourteen FCHL patients received 4 capsules daily of Omacor (an omega-3 polyunsaturated fatty acid [omega3 FA] concentrate providing 1.88 g of eicosapentaenoic acid [EPA] and 1.48 g of docosahexaenoic acid [DHA] per day; Pronova Biocare, Oslo, Norway) or placebo for 8 weeks in a randomized, double-blind, crossover study. Plasma triglycerides were 44% lower, and LDL cholesterol and apoliporpotein (apo)B were 25% and 7% higher after Omacor than placebo. HDL cholesterol was higher (+8%) after Omacor than placebo, but this difference did not achieve statistical significance. Omacor caused a selective increase of the more buoyant HDL(2) subfraction; plasma HDL(2) cholesterol and total mass increased by 40% and 26%, respectively, whereas HDL(3) cholesterol and total mass decreased by 4% and 6%. Both HDL(2) and HDL(3) were enriched in cholesteryl esters and depleted of triglycerides after Omacor. No changes were observed in the plasma concentration of major HDL apolipoproteins, LpA-I and LpA-I:A-II particles, lecithin:cholesterol acyltransferase (LCAT), and cholesteryl ester transfer protein (CETP). The plasma concentration of the HDL-bound antioxidant enzyme paraoxonase increased by 10% after Omacor. Omacor may be helpful in correcting multiple lipoprotein abnormalities and reducing cardiovascular risk in FCHL patients.
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PMID:An omega-3 polyunsaturated fatty acid concentrate increases plasma high-density lipoprotein 2 cholesterol and paraoxonase levels in patients with familial combined hyperlipidemia. 1476 65

Primary hyperlipidemia is caused by various molecular defects in lipid metabolism. The Research Committee on Primary Hyperlipidemia organized by the Ministry of Health and Welfare of Japan (present: the Ministry of Health, Labour and Welfare) has investigated reported mutations in Japanese patients with primary hyperlipidemia and related disorders (including hypolipidemia), and has created a database based on the questionnaire sent to the members of council board of the Japan Atherosclerosis Society. Mutations in the following genes were investigated: low density lipoprotein receptor, lecithin: cholesteryl acyltransferase, lipoprotein lipase (LPL), hepatic lipase, apolipoproteins A-I, A-II, A-IV, B, C-II, C-III and E, microsomal triglyceride transfer protein, and cholesterol ester transfer protein (CETP). Until 1998, 922 patients with primary hyperlipidemia and related disorders has been registered with the Research Committee, and 190 mutations in 15 genes had been reported, showing a marked variation in Japanese patients with primary hyperlipidemia and related disorders. So-called "common mutations" have been described in Japanese patients with familial hypercholesterolemia, LPL deficiency and CETP deficiency. The genetic defect of familial combined hyperlipidemia (FCHL) is still unknown although FCHL is speculated to be the most prevalent genetic hyperlipidemia, and further investigations should be performed to elucidate the molecular mechanisms of FCHL
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PMID:Mutations in Japanese subjects with primary hyperlipidemia--results from the Research Committee of the Ministry of Health and Welfare of Japan since 1996--. 1525 64

The role of lipids, lipoproteins and lipoprotein(a) [Lp(a)] in coronary artery disease (CAD) is known but the role of major apolipoproteins (apos) other than apo A-I and apo B remains unclear. In this study, using immunoturbidimetry we have estimated serum levels of total cholesterol, HDL-C, LDL-C, triglyceride, LDL-apoB and all major apos; A-I, A-II, B, C-II, C-III and E, in 751 healthy Indian subjects (470 men and 281 women, age 25-65 years), determined their percentiles, and established reference intervals. The effects of age, smoking and alcohol on all these analytes were also evaluated. This is the first study to provide reference intervals for all apos, in both sexes from a general population. The percentiles and the reference intervals have clinical relevance and will be useful in assessing the risk of CAD in patients with hyperlipidemia and other diseases.
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PMID:Lipid, lipoprotein, apolipoprotein and lipoprotein(a) levels: reference intervals in a healthy Indian population. 1620 21

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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