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

We have compared steady-state mRNA levels of apolipoproteins AI, AII, AIV, CI, CII and CIII in liver and small intestine of rabbits fed on a cholesterol-rich diet for up to 16 weeks. Apolipoprotein (apo) AIV mRNA was detected in both liver and small intestine, while apo AII was not detected in either organ. Apo CI, apo CII and apo CIII were expressed only in liver and apo AI mRNA was detected only in small intestine. In small intestine, apo AIV and apo AI mRNA levels increased to a maximum at the 4th and 12th week of treatment, respectively. In liver there was a parallel increase in the mRNA levels of apo AIV, apo CI, apo CII and apo CIII, with maximum levels after 4 weeks of treatment. A 3-fold increase was found in apo CII and apo CIII hepatic transcription rates between hypercholesterolemic and control rabbits after 4 weeks of treatment, no longer detectable after 8 weeks. However, no changes were found in apo AIV and apo CI transcription rates. Changes in apolipoprotein mRNA levels were accompanied by changes in plasma lipoprotein levels. Overall, these changes correlate well with the variations detected in the expression of the different apolipoprotein genes. Our results indicate that dietary cholesterol plays an important role in the regulation of these genes and that this regulation is tissue dependent.
Atherosclerosis 1992 Jul
PMID:Hypercholesterolemia induces differential expression of rabbit apolipoprotein A and C genes. 164 96

On theoretical grounds, an apo E receptor defect should be manifested by the accumulation of lipoprotein remnants that are normally cleared by this receptor and cannot be processed by the normal apo B, E receptor (LDL-receptor). Furthermore, the defect should not be selective for a specific apo E phenotype since none of the isoforms would be cleared preferentially. Our search for such an occurrence led us to the discovery, in five members of a family of ten, of a unique dyslipoproteinemia mimicking type III. As in type III, plasma levels of cholesterol, triglycerides, VLDL-cholesterol, VLDL-triglycerides and apo E, as well as the VLDL-C/TG ratio, were high. LDL-cholesterol and HDL-cholesterol tended to be low. The clearance of plasma triglycerides after a fat load was impaired. Tubero-eruptive xanthomas, arcus corneae and manifestations of atherosclerosis were present in some individuals. In contrast to type III, the dyslipoproteinemia occurred in subjects bearing three different apo E phenotypes: E4/2, E4/3 and E3/2. VLDL-apo B levels were markedly increased, the VLDL-C/VLDL-B ratio was low and a double pre-beta band was present on lipoprotein electrophoresis. In spite of high apo E and borderline high apo CIII plasma levels, levels of the lipoprotein particles LpCIII:B and LpE:B, which characterize type III, were not raised. Rapid weight loss or treatment with a fibrate was observed to normalize the lipoprotein profile. It is surmised that the apo E-rich lipoprotein particles accumulating in this type III phenocopy with "hyperapoprebetalipoproteinemia" could be those that are normally cleared by an apo E receptor.
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PMID:A phenocopy of type III dysbetalipoproteinemia occurring in a candidate family for a putative apo E receptor defect. 164 30

Lipid and apoprotein composition of four very low density lipoprotein (VLDL) subfractions decreasing in Sf value were evaluated in the fasting state in 12 normolipidemic Pima Indians (6 M, 6 F, age 39 +/- 1.7 yrs) (mean +/- SEM) with non-insulin-dependent diabetes mellitus (NIDDM) in poor glycemic control (HbA1 9.8 +/- 2.9%) and in 14 normoglycemic Pima controls matched for age, BMI and lipid values. Total cholesterol (CHOL), triglyceride (TG), phospholipids (PL), total protein (TP), apo B, apo CII, apo CIII and apoE were assayed in total VLDL and in each of the four VLDL subfractions designed as A (Sf greater than 400), B (Sf 175-400), C (Sf 100-175), and D (Sf 20-100). Diabetics compared to nondiabetics had higher concentrations of all constituents of VLDL D, with the largest changes being in TG (38.0 +/- 3.8 vs 28.0 +/- 2.5 mg/dl, P less than 0.04), PL (14.0 +/- 1.3 vs 10.0 +/- 1.0 mg/dl, P less than 0.04), TP (9.8 +/- 0.8 vs 7.6 +/- 2.4 mg/dl, P less than 0.05), apo B (6.3 +/- 0.5 vs 4.7 +/- 0.4 mg/dl, P less than 0.03) and apoE (0.73 +/- 0.09 vs 0.52 +/- 0.04 mg/dl, P less than 0.04). Since no difference was found between the groups in percentage composition of lipids or apoproteins in total VLDL and in all VLDL subfractions, the data suggest that in diabetics, even when normolipidemic, there is an increase in the number rather than in the composition of the smallest VLDL subfraction (VLDL D), which are usually considered to be more atherogenic.
Atherosclerosis 1991 Nov
PMID:Alterations in very low density lipoprotein subfractions in normotriglyceridemic non-insulin-dependent diabetics. 181 50

A number of studies have reported that a variant allele (S2) of the apo AI/CIII/AIV complex is associated with high plasma lipid levels in some populations and furthermore that the frequency of this allele is 2-5-fold higher in patient groups with premature coronary heart disease compared to control groups. This study shows in the healthy "English" population that the S2 allele is associated with elevated plasma apo CIII levels but not with low apo AI levels. In addition, it shows that the allele is associated with elevated plasma levels of apo B in men. Regression analysis shows in both men and women that apo CIII levels are positively correlated with plasma triglyceride levels and moreover that they are a stronger predictor of this parameter than apo AI, B or AIV. Apo CIII levels are also an independent predictor of total plasma cholesterol and HDL-cholesterol levels in males and females, respectively. Together these data suggest that a genetic predisposition to develop elevated plasma levels of apo CIII, alone or in combination with elevated plasma apo AIV levels, is the primary defect responsible for the association of the S2 allele with hyperlipidemia and/or premature CHD.
Atherosclerosis 1991 Apr
PMID:Variation at the apo AI/CIII/AIV gene complex is associated with elevated plasma levels of apo CIII. 190 14

Despite great interest in the role of lipids in overall and disease-free survival, virtually no information is available on the lipids, lipoproteins and apolipoproteins of persons over 90 years of age. Furthermore, the genetic underpinnings of atherosclerosis and the particular genetic factors responsible for protection against coronary artery disease remain speculative. In Bloomfield, Nebraska, we studied 41 nonagenarians (10 males, 31 females), with a mean age of 92.7 years, in whom lipids, lipoproteins, apolipoproteins and restriction fragment length polymorphisms (RFLPs) of genes for apolipoprotein B (apo B), aop AI and apo CIII were assessed. Nearly complete historical, physical and laboratory data were obtained on 39 subjects. The mean diastolic and systolic blood pressures for this group were nonhypertensive, body mass indices (weight/height2) had a mean of 23.9 and triceps skinfold thickness measurements an overall mean of 14.8 mm. The mean total serum cholesterol was 5.42 mmol/l. HDL-cholesterol levels in females persisted to be higher when compared to males (P less than 0.013). The allele frequencies for apo AI (MspI and PstI), apo CIII (Sst) and apo B (XbaI) gene RFLPs were typical for larger population studies. In these preliminary studies, we did not identify a distinctive phenotype, genotype, or phenotype-genotype relationship. Diversity of cardiovascular risk was the hallmark of these nonagenarians.
Atherosclerosis 1990 Aug
PMID:Lipid phenotypes, apolipoprotein genotypes and cardiovascular risk in nonagenarians. 197 83

Six RFLPs in the apolipoprotein (apo) AI-CIII-AIV gene region detected with the restriction enzymes XmnI, MspI, PstI, SstI and PvuII were used to study the role of genetic variation at this locus in the development of coronary heart disease and in the regulation of serum levels of various lipid and lipoprotein parameters in the Austrian population. 106 male patients with coronary heart disease and 118 matched controls were investigated. None of the alleles defined by these RFLPs was associated with increased coronary risk. In the patients, but not in the control group individuals with the genotype P1P2 for the PstI polymorphism in the 3' flanking region of the apo AI gene had significantly lower serum levels of high density lipoprotein (HDL)-cholesterol and apo AI levels than those with the genotype P1P1. The S2 allele of the SstI polymorphism at the 3' end of the apo CIII gene was significantly associated with elevated serum levels of triglycerides in the patient, but not in the control group. Controls with the genotype V2V2 for the PvuII(A) polymorphism at the 5' end of the apo CIII gene had significantly higher serum levels of apo B than those with V1V1 or V1V2. This association did not exist among the patients. These findings suggest that variation associated with some of these RFLPs is contributing to the determination of lipid levels in patients and controls, but that the RFLPs themselves cannot be used as markers for increased coronary risk in the Austrian population.
Atherosclerosis 1988 Oct
PMID:Genetic variation in the apolipoprotein AI-CIII-AIV gene cluster and coronary heart disease. 290 49

The hyperlipidemias, with hypertension, diabetes mellitus and cigarette smoking, are amongst the major risk factors for the development of atheroma. The inter-relationships of hyperlipidemia and atheroma are complex but both appear to have a strong inherited component. Amongst the multiple genetic factors determining the common forms of hyperlipidemia, the apolipoprotein genes coding for the major peptides of the plasma lipoproteins (chylomicrons, VLDL, LDL and HDL) may be of particular relevance since the latter form a system of inter-converting particles for the delivery of lipid (triglyceride and cholesterol) to peripheral tissues (including the arterial wall). Recently several apolipoprotein genes have been isolated. Particularly interesting results have been obtained with the apolipoprotein AI and CIII genes. The DNA sequence of both genes and their immediate flanking region was determined. The two genes are physically linked and convergently transcribed. The cloning of the apolipoprotein genes made possible a detailed genetic study of patients with defects in lipid metabolism. An altered apo AI gene was shown to be inherited as a Mendelian trait linked to premature atherosclerosis in an affected family. Furthermore, the alteration of the apo AI gene seems to affect the expression of the apo CIII gene. Another DNA polymorphism that generates a new SstI site was shown to be present at low frequency (8%) in a random sample of the population. However, its frequency increased dramatically (42%) in a group of hypertriglyceridemic patients. It is thus not inconceivable that further studies of the genes involved in lipid metabolism will eventually help to replace the present phenotype based classification of lipid metabolism disorders by a genotype based system.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Lipoprotein genes and hyperlipidemia. 649 70

Lipoprotein classes isolated from the plasma of two patients with apolipoprotein AI (apo AI) and apolipoprotein CIII (apo CIII) deficiency were characterized and compared with those of healthy, age- and sex-matched controls. The plasma triglyceride values for patients 1 and 2 were 31 and 51 mg/dl, respectively, and their cholesterol values were 130 and 122 mg/dl, respectively; the patients, however, had no measurable high density lipoprotein (HDL)-cholesterol. Analytic ultracentrifugation showed that patients' S degrees f 0-20 lipoproteins possess a single peak with S degrees f rates of 7.4 and 7.6 for patients 1 and 2, respectively, which is similar to that of the controls. The concentration of low density lipoprotein (LDL) (S degrees f 0-12) particles, although within normal range (331 and 343 mg/dl for patients 1 and 2, respectively), was 35% greater than that of controls. Intermediate density lipoproteins (IDL) and very low density lipoproteins (VLDL) (S degrees f 20-400) were extremely low in the patients. HDL in the patients had a calculated mass of 15.4 and 11.8 mg/dl for patients 1 and 2, respectively. No HDL could be detected by analytic ultracentrifugation, but polyacrylamide gradient gel electrophoresis (gge) revealed that patients possessed two major HDL subclasses: (HDL2b)gge at 11.0 nm and (HDL3b)gge at 7.8 nm. The major peak in the controls, (HDL3a)gge, was lacking in the patients. Gradient gel analysis of LDL indicated that patients' LDL possessed two peaks: a major one at 27 nm and a minor one at 26 nm. The electron microscopic structure of patients' lipoprotein fractions was indistinguishable from controls. Patients' HDL were spherical and contained a cholesteryl ester core, which suggests that lecithin/cholesterol acyltransferase was functional in the absence of apo AI. The effects of postprandial lipemia (100-g fat meal) were studied in patient 1. The major changes were the appearance of a 33-nm particle in the LDL density region of 1.036-1.041 g/ml and the presence of discoidal particles (12% of total particles) in the HDL region. The latter suggests that transformation of discs to spheres may be delayed in the patient. The simultaneous deficiency of apo AI and apo CIII suggests a dual defect in lipoprotein metabolism: one in triglyceride-rich lipoproteins and the other in HDL. The absence of apo CIII may result in accelerated catabolism of triglyceride-rich particles and an increased rate of LDL formation. Additionally, absence of apo CIII would favor rapid uptake of apo E-containing remnants by liver and peripheral cells. Excess cellular cholesterol would not be removed by the reverse cholesterol transport mechanism since HDL levels are exceedingly low and thus premature atherosclerosis occurs.
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PMID:Familial apolipoprotein AI and apolipoprotein CIII deficiency. Subclass distribution, composition, and morphology of lipoproteins in a disorder associated with premature atherosclerosis. 650 64

After 30 days of clofibrate administration to 11 patients with type IV hyperlipoproteinemia, a significant fall was observed in serum triglyceride and cholesterol levels. In the VLDL fraction the concentrations of triglycerides, cholesterol and apo B were significantly decreased. The apo CII/apo CIII ratio was raised. Cholesterol concentration changes in LDL and HDL fractions were not significant.
Atherosclerosis 1980 Apr
PMID:The influence of clofibrate on lipid and protein components of very low density lipoproteins in type IV hyperlipoproteinaemia. 737 19

The human cholesteryl ester transfer protein (CETP) facilitates the transfer of cholesteryl ester from HDL to triglyceride-rich lipoproteins. The activity of CETP results in a reduction in HDL cholesterol levels, but CETP may also promote reverse cholesterol transport. Thus, the net impact of CETP expression on atherogenesis is uncertain. The influence of hypertriglyceridemia and CETP on the development of atherosclerotic lesions in the proximal aorta was assessed by feeding transgenic mice a high cholesterol diet for 16 wk. 13 out of 14 (93%) hypertriglyceridemic human apo CIII (HuCIII) transgenic (Tg) mice developed atherosclerotic lesions, compared to 18 out of 29 (62%) controls. In HuCIII/CETPTg, human apo AI/CIIITg and HuAI/CIII/CETPTg mice, 7 of 13 (54%), 5 of 10 (50%), and 5 of 13 (38%), respectively, developed lesions in the proximal aorta (P < .05 compared to HuCIIITg). The average number of aortic lesions per mouse in HuCIIITg and controls was 3.4 +/- 0.8 and 2.7 +/- 0.6, respectively in HuCIII/CETPTg, HuAI/CIIIg, and HuAI/CIII/CETPTg mice the number of lesions was significantly lower than in HuCIIITg and control mice: 0.9 +/- 0.4, 1.5 +/- 0.5, and 0.9 +/- 0.4, respectively. There were parallel reductions in mean lesion area. In a separate study, we found an increased susceptibility to dietary atherosclerosis in nonhypertriglyceridemic CETP transgenic mice compared to controls. We conclude that CETP expression inhibits the development of early atherosclerotic lesions but only in hypertriglyceridemic mice.
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PMID:Decreased early atherosclerotic lesions in hypertriglyceridemic mice expressing cholesteryl ester transfer protein transgene. 756 Jan 1


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