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)

A significant factor associated with hiperglycaemia in diabetes is the resultant post-translational non-enzymatic glycation of plasma and cellular proteins. This process occurs in vivo by direct chemical reaction of glucose with protein alpha and epsilon amino groups. Because of the diverse evidences for direct involvement of non-enzymatic glycation of lipoproteins in the accelerated development of atherosclerosis in diabetic patients, most attention has been focused on the pathological properties of glycated lipoproteins. Glycation of LDL was found significantly increased in diabetic patients compared with normal subjects, even in the presence of good glycemic control. Metabolic abnormalities associated with glycation of LDL include diminished recognition of LDL by the classical LDL-receptor, and enhancement uptake of LDL by a low-affinity, high capacity receptor pathway on macrophages, thus stimulating foam cell formation, an early feature of atherosclerosis. Moreover, glycated LDL are more susceptible to oxidative modification than non-glycated LDL and glycation of LDL may alter their structure sufficiently to render them immunogenic. Being immunogenic, glycated-LDL accumulates in plasma and may enhance cholesterol ester accumulation in macrophages. Non-enzymatic glycation of HDL impairs its recognition by cells and induce a diminished efflux of cholesterol from cell membranes to HDL particles. Furthermore, glycated apolipoprotein A-1 isolated from plasma of diabetic subjects was deficient in activating lecithin: cholesterol acyl transferase, the driving force in reverse cholesterol transport, pathway responsible of the antiatherogenic properties of HDL.
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PMID:[Non-enzymatic glycosylation of lipoproteins in the pathogenesis of atherosclerosis in diabetics]. 946 Feb 89

Scavenger receptor BI (SR-BI) is a cell surface receptor that binds high density lipoproteins (HDL) and mediates selective uptake of HDL cholesteryl esters (CE) in transfected cells. To address the physiological role of SR-BI in HDL cholesterol homeostasis, mice were generated bearing an SR-BI promoter mutation that resulted in decreased expression of the receptor in homozygous mutant (designated SR-BI att) mice. Hepatic expression of the receptor was reduced by 53% with a corresponding increase in total plasma cholesterol levels of 50-70% in SR-BI att mice, attributable almost exclusively to elevated plasma HDL. In addition to increased HDL-CE, HDL phospholipids and apo A-1 levels were elevated, and there was an increase in HDL particle size in mutant mice. Metabolic studies using HDL bearing nondegradable radiolabels in both the protein and lipid components demonstrated that reducing hepatic SR-BI expression by half was associated with a decrease of 47% in selective uptake of CE by the liver, and a corresponding reduction of 53% in selective removal of HDL-CE from plasma. Taken together, these findings strongly support a pivotal role for hepatic SR-BI expression in regulating plasma HDL levels and indicate that SR-BI is the major molecule mediating selective CE uptake by the liver. The inverse correlation between plasma HDL levels and atherosclerosis further suggests that SR-BI may influence the development of coronary artery disease.
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PMID:Targeted mutation reveals a central role for SR-BI in hepatic selective uptake of high density lipoprotein cholesterol. 953 89

Hypothyroidism leads to an increase of plasma low-density lipoprotein (LDL) cholesterol levels. Oxidation of LDL particles changes their intrinsic properties, thereby enhancing the development of atherosclerosis. T4 has three specific binding sites on apolipoprotein B; furthermore it inhibits LDL oxidation in vitro. We therefore hypothesized that T4 deficiency not only results in elevated LDL-cholesterol levels but also in increased LDL oxidation. Ten patients with overt hypothyroidism were studied when untreated (TSH 76 +/- 13 mU/L, T4 40 +/- 6 nmol/L) and again when they were euthyroid for at least 3 months during T4 treatment (TSH 2.7 +/- 0.5 mU/L, T4 115 +/- 11 nmol/L). Plasma lipids and lipoproteins and the oxidizability and chemical composition of LDL were determined. The transition from the hypothyroid to the euthyroid state was associated with a decrease (mean +/- SE) of plasma total cholesterol (5.8 +/- 0.3 vs. 4.8 +/- 0.2 mmol/L, P < 0.005), LDL cholesterol (3.8 +/- 0.3 vs. 2.9 +/- 0.2 nmol/L, P < 0.005) and apolipoprotein B (1.2 +/- 0.1 vs. 0.9 +/- 0.1 g/L, P < 0.005); plasma high-density lipoprotein cholesterol, apolipoprotein A-1, and triglycerides did not change. The actual content of dienes in LDL particles was increased in hypothyroidism, with a decrease after T4 suppletion [median (range) = 257 (165-346) vs. 188 (138-254) nmol/mg LDL protein, P < 0.005; reference range 140-180]. The lag time, an estimate of the resistance of LDL against oxidation in vitro, was shortened when hypothyroid but normalized after T4 treatment [29 (19-90) vs. 77 (42-96) min, P < 0.005; reference range 67-87]. The density, the relative fatty acid content, and the vitamin E content of LDL particles did not change. In conclusion, the hypothyroid state is not only associated with a quantitative increase of LDL particles, but it also changes their quality by increasing LDL oxidizability.
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PMID:Increased oxidizability of low-density lipoproteins in hypothyroidism. 958 87

Remnants of chylomicron and very low density lipoprotein (VLDL) have been implicated as potentially atherogenic. Since endothelial dysfunction is an early event in atherosclerosis, we examined effects of the remnants on endothelium-dependent vasorelaxation. The remnant lipoproteins were isolated from postprandial plasma in hyperlipidemic subjects using the immunoaffinity gel mixture of anti apo A-1 and anti apo B-100 monoclonal antibodies and ultracentrifugation. Rabbit aortic strips suspended in the organ chambers were incubated for 2 h with the preparations of lipoproteins and lipids. After incubation, the strips were tested with vasodilators after precontraction with phenylephrine (1 microM). The remnant lipoproteins (750-1500 microg triglyceride/ml) but not VLDL fraction (up to 1500 microg triglyceride/ml) impaired vasorelaxation in responses to acetylcholine, substance P and A23187. Carbamylated or methylated remnant lipoproteins, chemically modified remnant lipoproteins, had comparable impairment of the vasorelaxation as unmodified remnant lipoproteins. Incubation with lipid extracts from the remnant lipoproteins also exerted an inhibitory effect on the vasorelaxation. Relaxation to sodium nitroprusside was fully preserved in all aortas exposed to the lipoprotein preparations. Thus, the remnant lipoproteins impair endothelium-dependent arterial relaxation at the concentrations observed in the plasma in patients with coronary artery disease (500-2000 microg triglyceride of remnant lipoprotein/ml). The impairment may be in apoprotein receptor-independent manner, and the lipids in the remnants seem to contribute to the inhibitory effect. The endothelial dysfunction caused by the remnant lipoproteins may play a role in the high prevalence of atherosclerotic coronary artery disease in postprandial hyperlipidemic patients.
Atherosclerosis 1998 Apr
PMID:Remnants of chylomicron and very low density lipoprotein impair endothelium-dependent vasorelaxation. 962 77

Fibrates are a standard in the treatment impaired lipid metabolism, in particular in combined disorders. The classical Helsinki trial provided evidence of a decreased incidence of IHD in the treated group as compared with the group on placebo. Moreover there is some recent work which proved by statistical methods regression of atherosclerosis after fibrate administration, e.g. the angiographic study BECAIT with bezafibrate. The objective of the present study was to test the effectiveness of bezafibrate (Regadrin B, 200 mg tablets, Berlin-Chemie, FRG) in patients with combined familial hyperlipidaemia. The total cholesterol concentration dropped by 12.7% the LDL-cholesterol concentration by 8.8%. There was a significant drop of triacylglycerols by 37% and a rise of HDL-cholesterol by 24.2%. The apoB concentration declined by 11.3% and apo A-1 increased by 19.6%. The fibrinogen value dropped significantly by 15.2%, the Lp(a) value did not change significantly. The body weight in the two groups did not change significantly. The achieved results resemble those of work published abroad. In the authors opinion it is a positive feature that it proved possible to engage the patients in regular aerobic physical activity. Bezafibrate, Regadrin B was well tolerated by the patients, neither clinical nor laboratory tests revealed significant undesirable effects.
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PMID:[Bezafibrate in the treatment of familial combined hyperlipidemia and its effect on certain parameters of lipid metabolism, particularly fibrinogen]. 982 67

Diet-induced hyperlipidaemia in baboons is similar to that in humans. As in humans, the ratio between low density lipoprotein (LDL) and high density lipoprotein (HDL) cholesterol is a major determinant of atherosclerosis. Baboons, like humans and other non-human primates, vary in their lipaemic responses to dietary lipids. By selective breeding based on variability in plasma and lipoprotein cholesterol response to diet, lines of baboons with high and low responses of various lipoproteins have been developed. Genetic analyses suggest that lipoprotein patterns in response to dietary cholesterol and fat are heritable. Metabolic and molecular studies of high and low LDL and HDL cholesterol responses to dietary lipids have suggested that different mechanisms regulate plasma LDL cholesterol on the chow and on the high cholesterol-high fat (HCHF) diet. On the chow diet, plasma LDL cholesterol levels are positively associated with cholesterol absorption and negatively associated with hepatic LDL receptor levels and, thus, cholesterol absorption and LDL receptors seem to regulate plasma LDL cholesterol levels. However, when the animals consume a human-like fat- and cholesterol-enriched diet, plasma LDL cholesterol levels are not associated with either cholesterol absorption or hepatic LDL receptor mRNA levels, but are negatively associated with plasma 27-hydroxycholesterol concentrations, hepatic sterol 27-hydroxylase activity, and mRNA levels. Hepatic sterol 27-hydroxylase activity and mRNA levels are induced by dietary cholesterol and fat in low responding baboons more than in high responding baboons. Thus, the ability to induce sterol 27-hydroxylase determines the LDL cholesterol response in baboons. High HDL response baboons often have high levels of HDL1 in their plasma. Our studies suggest that the N-terminal fragment of apo C-I with 38 amino acids and a molecular weight of approximately 4 kDa acts as a cholesteryl ester transfer inhibitor peptide in high HDL1 baboons. The inhibitor peptide associates with apo A-1 in HDL to produce a modified apo A-1 protein with a molecular weight of approximately 31 kDa. The inhibitor peptide is a gene product and the presence of this peptide produces an antiatherogenic high HDL1 phenotype.
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PMID:Diet, plasma lipoproteins and experimental atherosclerosis in baboons (Papio sp.). 982 56

While there have been ample studies of a cross-cultural nature and experimental evaluations establishing the cardioprotective effect of soy protein, efforts to clarify the proportion of those benefits related to its phytoestrogen content are relatively recent. In most cases, the general approach to evaluating the role of soy's phytoestrogens has been to compare the cardiovascular benefits of isolated soy protein with a comparable soy protein isolate that has been alcohol extracted. Based on that approach, soy phytoestrogens appear to lower low-density lipoprotein concentrations while increasing plasma concentrations of the high-density lipoproteins. Particularly noteworthy with respect to the high-density lipoprotein effects are the increases in apolipoprotein A-1. Phytoestrogens may also prevent the oxidation of lipoprotein particles. The soy phytoestrogens favourably influence coronary artery reactivity. They also inhibit the progression of atherosclerosis in the coronary, iliac and common and internal carotid arteries. The cardiovascular benefits of soy phytoestrogens appear to be equal for males and females.
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PMID:Phytoestrogens and coronary heart disease. 1038 15

Diabetes mellitus (DM) alters carbohydrate and lipid metabolism to a great extent. This study was planned to determine whether infants of insulin dependent and gestational diabetic mothers have abnormal lipid metabolism. Three groups of newborns were included in the study; group I consisted of 7 infants of diabetic mothers (IDM) with insulin dependent DM (Type 1 DM), group II of 18 infants of gestational diabetic mothers and group III of 20 control neonates whose mothers had no history of DM. Total cholesterol (TC), triglyceride (TG) and high density lipoprotein-cholesterol (HDL-C) values in groups I and II were no different compared to those in group III (p > 0.05). However, low density lipoprotein-cholesterol (LDL-C) and LDL-C/HDL-C ratio were similar between groups I and II (p > 0.05) but significantly higher in both infants of type 1 diabetic mothers and gestational diabetic mothers compared to control infants (p < 0.05). Apolipoprotein A-I (Apo A-1) and apolipoprotein B (Apo B) levels, Apo A-I/Apo B and HDL-C/Apo A-I ratios were similar in between groups. However, Apo B/LDL-C ratio was significantly lower in groups I and II compared to control group (p < 0.05). In conclusion, diabetes in pregnant women causes a tendency to LDL hypercholesterolemia in the offspring. These infants should be longitudinally followed up to assess whether this observation imposes an increased risk for atherosclerosis for advanced ages.
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PMID:Serum lipid and lipoprotein composition in infants of diabetic mothers. 1079 86

Mean high-density lipoprotein cholesterol (HDL-C) concentrations are low in the Jewish population of Israel. With this in mind we assessed the association of the Taq1B CETP polymorphism, plasma CETP mass and plasma lipid, lipoprotein and apolipoprotein concentrations in a sample of 884 Jerusalem residents aged 28-32. The allele frequency (0.435 +/- 0.017(S.E.)) is similar to that reported elsewhere. There was a strong (apparently codominant) association of the Taq1 B allele with plasma CETP in both sexes, and an inverse association with HDL-C and apo A-1, significant in women and undiminished upon adjustment for plasma CETP. There was evidence in this population for an admixture of two plasma CETP distributions, with 9% belonging to a distribution with the higher mean, pointing to a possible major gene effect. Mean plasma CETP was higher in women than men. Plasma CETP was inversely associated with HDL-C in men but not in women (P< 0.05 for the sex difference, multivariate analysis), inversely related to the HDL-C/apo A-1 ratio in men and positively related in women (P < 0.005 for the sex difference), and was positively associated with total cholesterol (TC) and low-density lipoprotein cholesterol in both sexes, and with the TC/HDL-C ratio and apo B in men alone. The sex differences may reflect dissimilarities in the regulatory function of CETP in lipid exchange. The absence of an unusual allele frequency of the Taq1B CETP polymorphism and its relatively modest association with HDL-C argue against an important role for this or strongly linked sites in determining the low population levels of HDL-C in Israel.
Atherosclerosis 2000 Aug
PMID:Taq1B CETP polymorphism, plasma CETP, lipoproteins, apolipoproteins and sex differences in a Jewish population sample characterized by low HDL-cholesterol. 1092 28

Apolipoprotein E (apo E), a 34 kDa component of lipoproteins produced by the liver and in circulating macrophages, plays a critical role in the reverse transport of cholesterol to the liver via the circulation. Cholesterol-rich macrophages (macrophage foam cells) are a major cell type in human atherosclerotic lesions. Apo E deficiency in mice leads to the formation of atherosclerotic lesions. Conversely, macrophage-specific expression of apo E in these deficient mice can reduce the extent of atherosclerosis. These observations, together with the anti-inflammatory and anti-proliferative properties of Apo E, demonstrate an atheroprotective role for the apolipoprotein. Agents that regulate macrophage metabolism are also able to modulate apo E expression. Sterol loading, for example, enhances apo E synthesis and secretion. Additionally, exposure of macrophage foam cells to cholesterol acceptors such as apo A-1, the protein component of high density lipoprotein, further enhance apo E secretion. Cytokines can have a negative regulatory effect on apo E production in macrophages. Apo E expression is controlled at the transcriptional, post-transcriptional and post-translational level. Here, we review the cellular and molecular mechanisms modulating apo E synthesis and secretion in macrophages.
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PMID:Regulation of apolipoprotein E production in macrophages (review). 1093 85


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