bluuebunny/crossref_metadata_2025 huggingface dataset:
Inheritance of low density lipoprotein subclass patterns in familial combined hyperlipidemia.
Authors: Austin M A , Brunzell J D , Fitch W L , Krauss R M
Published: June 2011

The inheritance of low density lipoprotein (LDL) subclass patterns was investigated in 234 members of seven large kindreds with familial combined hyperlipidemia (FCHL), a disorder characterized by elevated LDL cholesterol and/or triglyceride and increased coronary disease risk in families. Analysis of LDL subclasses by nondenaturing gradient gel electrophoresis showed a predominance of large, buoyant LDL particles (pattern A) in 71% of the family members and a predominance of small, dense LDL particles (pattern B) in 29% of family members. Based on complex segregation analysis, pattern B appeared to be inherited as an autosomal trait with either a dominant or an additive mode of inheritance and a small, but significant, multifactorial inheritance component. The proposed allele for pattern B was common (frequency = 0.3), and reduced penetrance was observed among men under age 20 and among women under age 50. These results in these FCHL families are consistent with those from a previously reported population-based sample of families, in which pattern B showed an apparent dominant mode of inheritance. In that study, reduced penetrance was observed for men under age 20 and for premenopausal women, but a somewhat lower allele frequency was found for pattern B (0.25). In the FCHL family members, LDL subclass pattern B was associated with significantly increased plasma levels of apolipoprotein B and triglyceride and decreased high density lipoprotein cholesterol. In comparison with a group of controls, the FCHL family members with pattern A had similar mean triglyceride levels, but higher mean apolipoprotein B. Thus, in families with FCHL, a predominance of small, dense LDL particles appears to be inherited as a common, single-gene trait, which is closely associated with the higher plasma triglyceride levels found in these families. The increased plasma apolipoprotein B levels found in FCHL cannot, however, be accounted for by this proposed locus.
Platelet secretory products increase low density lipoprotein oxidation, enhance its uptake by macrophages, and reduce its fluidity.
Authors: Aviram M , Dankner G , Brook J G
Published: June 2011

Oxidized low density lipoprotein (Ox-LDL) is considered to be involved in the atherogenic process. Factors influencing the formation of Ox-LDL are thus of importance. Oxidation of LDL in a cell-free system in the presence of copper ions was significantly increased (up to 60%) by the presence of platelet-conditioned medium, (PCM) obtained from collagen-activated platelets for the duration of the oxidation period. The effect was time- and dose-dependent and was related to hydrogen peroxide and superoxide production, since PCM-induced enhanced LDL oxidation was inhibited by catalase and by superoxide dismutase, but not by protease treatments. PCM also reduced the fluidity of oxidized LDL by 45%. Upon incubation with a J-774 macrophage-like cell line, PCM-treated Ox-LDL enhanced cellular cholesteryl ester synthesis by 47% and lipoprotein degradation by 41%. Thus platelet secretory products appeared to enhance LDL oxidation through the involvement of oxidative agents. The resulting Ox-LDL demonstrated increased atherogenic properties.
Polyclonal antibodies against formaldehyde-modified apolipoprotein A-I. An approach to circumventing fixation-induced loss of antigenicity in immunocytochemistry.
Authors: Harrach B , Robenek H
Published: June 2011

A central requirement for the subcellular localization of synthesized and/or endocytozed lipoproteins is the availability of antibodies against the antigen to be localized. The preparation of cells for electron microscopy, in particular the fixation and embedding routine, influences the antigenicity, often resulting in a markedly reduced labeling intensity. To ameliorate fixation-induced changes in antigenicity, we produced antibodies against pre-fixed human apolipoprotein (apo) A-I. Purified apo A-I was fixed with 4% formaldehyde and was used to raise polyclonal antibodies in rabbits. The antiserum was purified by protein A-Sepharose followed by affinity chromatography with the fixed antigen coupled to vinylsulfone-activated agarose. The specificity of the antibodies was ascertained by enzyme-linked immunosorbent assay (ELISA) and Western blot analysis against different fixed and unfixed lipoproteins. Nonspecific binding to unfixed or to fixed apolipoproteins was not observed. Thus, the antibodies reacted specifically with apo A-I and recognized the fixed as well as the unfixed protein. In ELISA, the reaction of the antibodies was markedly enhanced with the fixed antigen, indicating that the antibodies were directed against epitopes characteristically modified by the fixation. The efficacy of the antibodies for light and electron microscopy was tested on HepG2 cells and on human liver cells which are known to synthesize apo A-I. When HepG2 cells were exposed to anti-apo A-I antibodies followed by a secondary fluorescein isothiocyante-labeled antibody, fluorescence was found intracellularly in distinct regions. Electron microscopy revealed that the endoplasmic reticulum, and in particular the trans elements of the Golgi complexes, were the main compartments stained for apo A-I both in HepG2 cells, as shown by the immunoperoxidase technique, and in human hepatocytes, as shown by the protein A-gold technique on ultrathin cryosections. Furthermore, we were able to localize apo A-I in foam cells of the human aortic plaque by postembedding immunolabeling techniques. These findings demonstrate the potential of antibodies to fixed lipoproteins in impaired localization at the light microscopic and electron microscopic levels.
Extracranial carotid atherosclerosis in patients with and without transient ischemic attacks and coronary artery disease.
Authors: Howard G , Ryu J E , Evans G W , McKinney W M , Toole J F , Murros K E , Crouse J R
Published: June 2011

We examined the extent of extracranial carotid atherosclerosis as evaluated by a B-mode ultrasound score in four groups of hospitalized patients: hospital controls free of both cerebrovascular symptoms and coronary atherosclerosis (HC, n = 245); patients with coronary atherosclerosis but without cerebrovascular symptoms (CAD, n = 382); patients with transient ischemic attacks but asymptomatic for coronary atherosclerosis (TIA, n = 107); and patients having both transient ischemic attacks and symptomatic coronary events (TIA + CAD, n = 39). The unadjusted B-mode scores were lowest for the HC group, intermediate for the CAD group, and highest for the TIA or TIA + CAD groups (no difference between these two groups). However, after adjustment for age (or age and other risk factors), we could find no significant differences among the CAD, TIA, and TIA + CAD groups, while the HC group had significantly lower adjusted scores. These data suggest that 1) accentuated development of carotid atherosclerosis is associated with both TIA and CAD and 2) the apparent differences in extracranial carotid atherosclerosis between coronary and cerebrovascular patients are partly attributable to differences in risk factor profiles (most notably age). The potentially accentuated rate of development of extracranial atherosclerosis in patients with CAD mandates a low threshold for cerebrovascular evaluation in CAD patients.
High density lipoprotein cholesterol. A 16-year longitudinal study in aging male twins.
Authors: Christian J C , Carmelli D , Castelli W P , Fabsitz R , Grim C E , Meaney F J , Norton J A , Reed T , Williams C J , Wood P D
Published: June 2011

The National Heart, Lung, and Blood Institute Twin Study is a collaborative, longitudinal study of white, male twins who were veterans of World War II and were born between 1917 and 1927. The twins were selected from the National Academy of Sciences/National Research Council Twin Panel and were examined three times (1969-73, 1981-82, and 1986-87). At all three exams, the dizygotic (DZ) twins were found to have a greater total variance for high density lipoprotein cholesterol (HDL-C) than the monozygotic (MZ) twins (p less than 0.05). DZ variance estimates were also larger than the variance of singletons from the second National Health and Nutrition Examination Survey. At the third exam, HDL-C was divided by precipitation into HDL2 and HDL3 fractions, and HDL2 was found to be the primary cause of the greater DZ total variance (DZ/MZ HDL2 variance = 2.22). The DZ/MZ variance ratio decreased 9% after adjustment of HDL2 for correlations with plasma triglycerides, alcohol consumption, smoking, exercise, and body mass index measured at the third exam. Postulated causes of the difference between MZ and DZ total variances include World War II induction screening, environmental influences unique to one zygosity, and genetic factors related to twinning. Further understanding of the etiology of this striking difference between MZ and DZ twin variance for HDL-C fractions could lead to more effective methods of decreasing the complications of arteriosclerosis.
Analysis of indium-111 platelet kinetics and imaging in patients with aortic grafts and abdominal aortic aneurysms.
Authors: Hanson S R , Kotzé H F , Pieters H , Heyns A D
Published: June 2011

To quantitatively characterize processes of platelet thrombus formation in vivo, the kinetics and incorporation into thrombus of autologous In-111-labeled platelets were compared in six patients with aortic aneurysms and in seven patients with prosthetic aortic grafts. Although platelet survival was comparably shortened in both patient groups (mean, 5.8 days), the maximum radioactivity (percentage of whole body radioactivity) as determined by gamma camera imaging was higher in the aneurysms than in the grafts (3.3% +/- 1.6% vs. 1.6% +/- 1.1%, p = 0.05). Maximum In-111 uptake was also attained more quickly in the aneurysm patients (2.3 +/- 0.8 days vs. 3.5 +/- 1.3 days; p = 0.07). The experimental platelet kinetic and imaging data were subsequently evaluated by compartmental analysis to estimate both normal and disease-related components of platelet destruction. This analysis indicated that deposited platelet radioactivity had a longer residence time on grafts (2.9 +/- 1.7 days vs. 1.4 +/- 0.9 days, p = 0.07) but accumulated at a faster rate in aneurysms (5.0% +/- 3.4% per day vs. 1.4% +/- 0.9% per day, p = 0.02). As determined by imaging, only a proportion of increased platelet destruction was specifically due to the aneurysms (55% +/- 38%) or grafts (17% +/- 11%, p = 0.03). This result indicates additional components of platelet destruction unrelated to graft and aneurysm thrombus formation which, in some graft patients, may reflect a greater severity of vascular disease or other mechanisms causing a preferential shortening of platelet survival. Thus, the analytical approach described may be a useful one for discriminating components of in vivo platelet utilization including platelet removal due to normal hemostatic and senescent mechanisms, localized thrombus formation, and more generalized vascular disease.
Relationship of endogenous sex steroid hormones to lipids and apoproteins in postmenopausal women.
Authors: Kuller L H , Gutai J P , Meilahn E , Matthews K A , Plantinga P
Published: June 2011

The relationships between blood levels of estrogen and lipoprotein lipids and apoproteins were evaluated in 120 women early in the climacteric. Among women who were 1-year amenorrheic, not taking hormone replacement therapy, and with follicle-stimulating hormone levels greater than 720 ng/ml, serum estradiol levels were positively related to concentrations of the high density lipoprotein 2 cholesterol (HDL2c) subfraction. There was a substantial decrease in HDL2c and apoprotein (apo) A-I in women whose estradiol levels decreased to less than or equal to 2.5 pg/ml from the first to the second postmenopausal examination. In a sample of women evaluated during the perimenopause (3-months' amenorrheic), those with the highest concentrations of estradiol or estrone showed a (nonsignificantly) higher level of HDL2c and a lower level of low density lipoprotein cholesterol (LDLc) than did those with the lowest concentration of estradiol or estrone. Estradiol levels declined dramatically between the perimenopausal and the postmenopausal examinations, and this was accompanied by a decrease in HDL2c and a nonsignificant increase in LDLc. HDL2c levels fell substantially in those women whose estradiol decreased below the sensitivity of the assay. The change, however, was not statistically significant. Estrone is the primary postmenopausal estrogen, and levels are directly related to obesity, as are levels of insulin. The interrelationship among obesity, conversion of estrone to estradiol at the tissue level, and insulin (or insulin sensitivity) is probably the primary determinant of HDLc concentration among postmenopausal women.
Serum lipid profile in an elderly Chinese population.
Authors: Woo J , Lam C W
Published: June 2011

The serum lipid profile of a cohort of Hong Kong Chinese subjects living in the community (160 men, 154 women, mean age 70.2 +/- 11.4 years) was examined to determine the influence of age, sex, indices of obesity, drugs, smoking, alcohol intake, and presence of diabetes mellitus on serum lipid, lipoprotein, and apolipoprotein concentrations. A high waist/hip ratio (an index of central obesity) was associated with higher serum triglyceride and lower apolipoprotein (apo) A-I concentrations, while a higher body mass index was associated with lower high density lipoprotein (HDL) cholesterol and higher apo B concentrations. Smokers and those taking beta-blockers had lower apo A-I concentrations. Subjects on methyldopa had higher triglyceride and very low density lipoprotein cholesterol, with lower HDL and HDL2 cholesterol. All the HDL fractions were lower in diabetic subjects, and cholesterol and triglyceride concentrations correlated with indices of glycemic control.
Characterization in vitro of interaction of human apolipoprotein E-free high density lipoprotein with human hepatocytes.
Authors: Schouten D , Kleinherenbrink-Stins M F , Brouwer A , Knook D L , Kamps J A , Kuiper J , van Berkel T J
Published: June 2011

Characterization of the interaction of iodinated apolipoprotein (apo) E-free high density lipoprotein (HDL) with cultured human hepatocytes provides evidence for a saturable, Ca2(+)-independent, high affinity binding site with an apparent km value of 20 micrograms/ml of apolipoprotein. Nitrated HDL and low density lipoprotein (LDL) did not compete for the binding of HDL, in contrast to very low density lipoprotein (VLDL). It is suggested that VLDL competition is exerted by the presence of apo Cs. Degradation of HDL was relatively low and in some cases not detectable. In cases where degradation was found, inhibitors of the lysosomal pathway of protein degradation had no effect, while LDL degradation was inhibited more than 80%. In the presence of 10 microM of monensin, the cell-association of HDL was unaffected, but the degradation was inhibited by 30%. Under similar conditions, LDL association was inhibited by 40% and LDL degradation, by 90%. Incubation of human hepatocytes with fluorescently labeled HDL (Dil-HDL) revealed (in contrast to Dil-LDL) mainly strong membrane-bound fluorescence and hardly any labeling of small intracellular vesicles. It is concluded that human hepatocytes possess a specific high affinity site for human HDL with recognition properties similar to those described earlier on rat hepatocytes. No evidence that the binding of HDL is actively coupled to uptake and lysosomal degradation could be obtained, indicating that binding of LDL and HDL to human hepatocytes is coupled differently to intracellular pathways.
Lipoprotein and apolipoprotein levels among Mexican-Americans in Starr County, Texas.
Authors: Hanis C L , Hewett-Emmett D , Douglas T C , Schull W J
Published: June 2011

Mexican-Americans represent the single largest component of the US Hispanic population and have been shown to bear a disproportionate burden of chronic disease. A representative sample of 1,004 Mexican-Americans aged 15-74 years from Starr County, Tex., was recruited for this study. Each subject was provided a detailed physical evaluation that included measurement of fasting levels of cholesterol, triglycerides, high density lipoprotein (HDL) cholesterol and its subfractions (HDL2 and HDL3) alpha- and beta-lipoprotein cholesterol, and low density lipoprotein cholesterol. Apolipoproteins A-I, A-II, B, C-II, C-III, and E were determined for approximately 550 of these individuals. Age- and sex-specific mean levels and percentile cut points are presented. The distributions of lipoproteins are quite similar to those of the general population except for consistently higher triglycerides in males and females and lower HDL cholesterol levels in females. These findings are consistent with the high frequency of obesity. Comparative age- and sex-specific data for the apolipoproteins are not widely available. Where such data exist, apolipoprotein levels observed in the Mexican-American population tend to be similar to or lower than the comparative data.
Dose response of dietary fish oil supplementations on platelet adhesion.
Authors: Li X L , Steiner M
Published: June 2011

A dose-response study of dietary fish oil supplementation on platelet adhesion was performed in three groups of five normal individuals each. Fish oil equivalent to 3, 6, or 9 g eicosapentaenoic acid (EPA)/day was administered for 3 weeks, and platelet adhesion was evaluated under high and low shear rate conditions in a laminar flow chamber before, during, and after termination of fish oil administration. Platelet adhesion to collagen I and fibrinogen, the two test surfaces in this study, was greatly reduced in response to fish oil. The inhibitory effect was similar whether platelet adhesion was evaluated at high or low shear rates. Maximal inhibitory activity was noted at 6 g EPA/day. A delayed onset and prolonged washout period characterized the response. The washout period of the fish oil effect was inversely related to the level of dietary supplementation. Measurement of total fatty acid distribution in platelets showed a dose-related increase in n-3 polyunsaturated fatty acids. From these studies, it is concluded that fish oil is an effective inhibitor of platelet adhesion, which reaches its maximum effect at approximately 6 g EPA/day.
Apolipoprotein E polymorphism association with lipoprotein profile in endogenous hypertriglyceridemia and familial hypercholesterolemia.
Authors: Dallongeville J , Roy M , Leboeuf N , Xhignesse M , Davignon J , Lussier-Cacan S
Published: June 2011

Apolipoprotein (apo) E polymorphism was among the first-reported genetic polymorphisms that explained part of the normal variation in plasma cholesterol concentrations in humans. The aim of this study was to assess the influence of allelic variation at the apo E gene locus on the plasma lipoprotein profile in hyperlipidemia. The lipoprotein levels of hyperlipidemic subjects of the major apo E phenotypes (E3/2, E3/3, and E4/3) were compared. One hundred eighty-two subjects with endogenous hypertriglyceridemia and 98 subjects with familial hypercholesterolemia due to a 10-kb deletion in their low density lipoprotein (LDL) receptor genes were compared with 424 normolipidemic controls from the same environmental background. LDL concentrations were lower in the E3/2 subset than in the E3/3 or E4/3 subset in the control, hypertriglyceridemic, and familial hypercholesterolemic groups. In absolute values, the magnitude of the effect was greatest in the familial hypercholesterolemic group. However, the direction and percentage change were identical in the presence or absence of the LDL receptor defect, indicating that the apo E phenotype effect is independent of LDL receptor status. Triglyceride and very low density lipoprotein (VLDL) cholesterol concentrations were higher in E3/2 than in E3/3 or E4/3 hypertriglyceridemic subjects, but this difference was not found in the familial hypercholesterolemic or control group. Thus, there seems to be a specific interaction between apo E isoforms and VLDL metabolism in hypertriglyceridemia; allelic variation at the apo E gene locus seems to be associated with specific alterations in the plasma lipoprotein profile of subjects with well-defined types of hyperlipidemia.
Hepatic lipase promotes a loss of apolipoprotein A-I from triglyceride-enriched human high density lipoproteins during incubation in vitro.
Authors: Clay M A , Newnham H H , Barter P J
Published: June 2011

Studies have been performed to investigate a possible mechanism to account for the low concentrations of apolipoproteins A-I (apo A-I) in subjects with hypertriglyceridemia. Incubation of human plasma in vitro with canine hepatic lipase resulted in the hydrolysis of approximately half the triglyceride in the high density lipoproteins (HDLs), but little change in the concentrations of other HDL constituents. However, when the plasma was supplemented with cholesteryl ester transfer protein and very low density lipoproteins to enrich the HDL with triglyceride, hepatic lipase promoted not only a significant reduction in HDL triglyceride acquired by the lipid transfer process but also an enhanced transfer of cholesteryl esters out of the particles. These changes were accompanied by a marked loss of apo A-I from HDL, which was demonstrated independently by ultracentrifugation, size-exclusion chromatography, and gradient gel-immunoblot analysis. The apo A-I lost from HDL was recovered in the "lipoprotein-free" fraction of plasma. The results of these studies indicate that primary reductions in the concentration of HDL core lipids in vitro are accompanied by a secondary loss of apo A-I from HDL. While recognizing the need for caution in any extrapolation from observations made in vitro to what may occur in vivo, these studies are nevertheless consistent with a proposition that the low concentration of apo A-I in subjects with hypertriglyceridemia is secondary to the reduced concentration of HDL core lipids in such subjects.
Moderate fish oil intake improves lipemic response to a standard fat meal. A study in 25 healthy men.
Authors: Brown A J , Roberts D C
Published: June 2011

To test the hypothesis that conditioning with a practical dose of fish oil will reduce postprandial lipemia, 25 healthy men were matched according to levels of fasting plasma triacylglyceride and allocated to 6 weeks of either fish oil or olive oil supplements (5 g/day). After a 12-hour overnight fast at the termination of the study period, the subjects were given a standard test meal containing 89% of energy as fat (0.73 g fat/kg body wt, polyunsaturated to saturated fat ratio = 0.4). Vitamin A (429 retinol equivalents/kg body wt) was included to endogenously label the chylomicrons. Venous blood samples were obtained before the test meal and hourly thereafter for 8 hours. Chylomicrons were separated by ultracentrifugation, plasma triacylglyceride concentration was determined enzymatically, and retinyl ester levels were measured by liquid chromatography. Postprandially, the fish oil-fed group exhibited mean total and chylomicron triacylglyceride concentrations that were significantly (p less than 0.05) less than those of the olive oil-fed group. Both the fish oil- and olive oil-fed groups had similar rises in chylomicron retinyl esters during the first 2 hours, but after this time the postprandial response of the fish oil-fed group was consistently and significantly (p less than 0.05) less than the response of the olive oil-fed group. Our results suggest that improvement in lipemic response, whether due to enhanced chylomicron clearance or decreased chylomicron entry into the plasma pool, can be achieved at a much lower intake of fish oil than previously reported.
Cholesterol-raising factor from boiled coffee does not pass a paper filter.
Authors: van Dusseldorp M , Katan M B , van Vliet T , Demacker P N , Stalenhoef A F
Published: June 2011

Previous studies have indicated that consumption of boiled coffee raises total and low density lipoprotein (LDL) cholesterol, whereas drip-filtered coffee does not. We have tested the effect on serum lipids of consumed coffee that was first boiled and then filtered through commercial paper coffee filters. Sixty-four healthy volunteers consumed six cups per day of this boiled and filtered coffee for 17 days. Then, they were randomly divided into three groups, which, for the next 79 days, received either unfiltered boiled coffee (lipid content, 1.0 g/l), boiled and filtered coffee (0.02 g lipid/l), or no coffee. Serum total cholesterol levels rose by 0.42 mmol/l (16 mg/dl; 95% confidence interval [CI], 0.14-0.71), LDL cholesterol levels by 0.41 mmol/l (16 mg/dl; 95% CI, 0.16-0.66), and apolipoprotein B levels by 8.6 mg/dl (95% CI, 3.8-13.4) in those who consumed boiled coffee relative to those who consumed boiled and filtered coffee. Responses of triglycerides, high density lipoprotein cholesterol, and apolipoprotein A-I did not differ significantly among these groups. No significant effects on serum lipid levels were found in the boiled and filtered coffee-consuming group compared with those who drank no coffee. In subjects who drank boiled coffee, serum campesterol level, an indicator of cholesterol absorption, remained constant. The serum lathosterol level, an indicator of cholesterol synthesis, increased by 11% (p less than 0.05), but the lathosterol to cholesterol ratio did not change. We propose that paper filters of the type used for drip-filtered coffee retain the lipid present in boiled coffee and in that way remove the hypercholesterolemic factor.(ABSTRACT TRUNCATED AT 250 WORDS)
Platelet function in Watanabe heritable hyperlipidemic rabbits. Decreased sensitivity to thromboxane A2.
Authors: Gross P L , Rand M L , Barrow D V , Packham M A
Published: June 2011

The characteristics of platelets from seven 5-7-month-old homozygous Watanabe heritable hyperlipidemic (WHHL) rabbits (plasma cholesterol, 13.9 +/- 1.7 mM, mean +/- SEM) were compared with those of platelets from normocholesterolemic age/weight- and sex-matched control rabbits (plasma cholesterol, 2.2 +/- 0.3 mM). Whole-blood platelet count and platelet size and protein content were not different in the two groups of rabbits, and the platelets from the WHHL rabbits were not enriched in cholesterol as indicated by identical mean cholesterol:phospholipid molar ratios (C/P). Responses of washed platelets stimulated with various agonists were studied to determine the effects of the genetically determined hypercholesterolemia on the various pathways of platelet aggregation in the absence of plasma components. In platelets from WHHL rabbits compared with controls, aggregation induced by ADP (0.5-5 microM) did not differ; collagen-induced (0.25-1.5 micrograms/ml) responses (aggregation, secretion of carbon-14-labeled serotonin from the amine storage granules of prelabeled platelets, and thromboxane A2 [TxA2] formation) were significantly less extensive; with aspirin-treated platelets, aggregation and secretion of granule contents induced by the TxA2 mimetic U46619 (0.25-1 microM) were significantly less extensive; and thrombin-induced (0.005-0.1 unit/ml) responses of untreated platelets (aggregation, secretion of granule contents, and TxA2 formation) or aspirin-treated platelets (aggregation and secretion of granule contents) did not differ. These observations are in direct contrast with previous studies of platelets from rabbits with diet-induced hypercholesterolemia, in which responses to TxA2 and thrombin were enhanced. Platelets from WHHL rabbits are hyposensitive to aggregation induced by TxA2.
Transforming potential is detectable in arteriosclerotic plaques of young animals.
Authors: Penn A , Hubbard F C , Parkes J L
Published: June 2011

The carcinogen-treated cockerel is a model for studying the early stages of arteriosclerotic plaque development. Carcinogen administration accelerates arteriosclerotic plaque development in cockerels, and transforming elements are present in DNA from advanced human plaques. In this study, we asked whether transforming elements could also be detected at early stages of plaque development in cockerels. NIH3T3 cells were transfected with DNA from plaques isolated from carcinogen-treated cockerels and from the healthy arterial wall underlying the plaques. Approximately 5 x 10(6) cells from each group were injected into nude mice. Tumors appeared in five of five mice in the plaque DNA group; no tumors appeared in mice from the healthy arterial wall group. All five plaque DNA-associated tumors hybridized to a cockerel genomic probe. Eight cockerel-specific bands were identified in EcoRI digests of first-round (primary) tumors. DNA from a primary tumor was tested in a second round of transfection. Five of five mice developed tumors after injection with these secondary transformants. All second-round tumors contained cockerel DNA, and a prominent cockerel-specific band (greater than 28 kb) was seen in EcoRI digests of all second-round tumors. In addition, a 5.2-kb band appeared prominently in one of five second-round tumors. No evidence was found for activation of the oncogenes Ha-ras, Ki-ras, src, or myc in the plaque-associated tumors. Similarly, DNA from plaque-associated tumors did not hybridize to probes for Marek disease virus, herpes simplex virus 1, or reverse transcriptase, suggesting that neither herpesviruses nor retroviruses are involved in the transforming activity of plaque DNA. These results indicate that transforming elements are a general property of arteriosclerotic plaques and are detectable in plaques of young animals.
Will a high-carbohydrate, low-fat diet lower plasma lipids and lipoproteins without producing hypertriglyceridemia?
Authors: Ullmann D , Connor W E , Hatcher L F , Connor S L , Flavell D P
Published: June 2011

A sudden increase in dietary carbohydrate invariably increases the plasma levels of very low density lipoprotein (VLDL) and triglyceride. The present studies were designed to test the hypothesis that dietary carbohydrate-induced hypertriglyceridemia need not occur. In the first study we fed gradually increasing amounts of carbohydrate and gradually decreasing amounts of fat to eight subjects. The usual American diet (40% fat, 45% carbohydrate, and 15% protein) was followed in sequence by four diets in a phased regimen, the carbohydrate increasing by 5% of total calories and the fat content decreasing by 5% for each dietary period. In the last dietary period (phase 4), 20% of the energy was in the form of fat and 65% in the form of carbohydrates; the cholesterol content was 100 mg/day. Throughout the study, plasma triglyceride and VLDL triglyceride levels did not change significantly. The plasma total and low density lipoprotein (LDL) cholesterol levels were greatly reduced, by 15% and 22%, respectively (p = 0.004). Plasma high density lipoprotein (HDL) cholesterol levels decreased concomitantly. In the second study, after a washout period six of the subjects were initially fed the phase 4 high-carbohydrate diet for a 10-day period. The plasma triglyceride concentration increased over baseline levels by 47%, and VLDL triglyceride levels increased by 73%. We conclude that although a sudden increase in dietary carbohydrate increases the plasma triglyceride level, patients gradually introduced to a high-carbohydrate, low-fat diet may achieve a significant reduction of plasma total and LDL cholesterol without developing carbohydrate-induced hypertriglyceridemia.
Dietary eicosapentaenoic acid and docosahexaenoic acid from fish oil. Their incorporation into advanced human atherosclerotic plaques.
Authors: Rapp J H , Connor W E , Lin D S , Porter J M
Published: June 2011

The incorporation of fatty acids from dietary fish oil was measured in obstructive atherosclerotic plaques removed from 11 patients fed fish oil, rich in omega-3 fatty acids, for 6-120 days before a planned arterial endarterectomy. The fatty acids of plasma and atheroma were analyzed with special reference to docosahexaenoic acid (DHA, 22:6) and eicosapentaenoic acid (EPA, 20:5), the principal omega-3 fatty acids of fish oil. The omega-3 fatty acid content increased greatly in plasma from 0.9% of fatty acids to 14.8% in cholesteryl esters, from 3.8% to 22.1% in phospholipids, and from 1.3% to 21.9% in triglycerides. The omega-3 fatty acid content of the atherosclerotic plaques was also greater when compared with that of plaques removed from 18 non-fish oil-fed controls. The omega-3 fatty acid in cholesteryl esters of the plaques was 4.9% in the experimental group versus 1.4% in control plaque, in phospholipids it was 8.8% versus 1.8%, and in triglycerides it was 4.7% versus 0.7% (p less than 0.001 for each lipid class). The two major omega-3 fatty acids (DHA and EPA) behaved differently. Compared with their respective plasma levels, relatively more DHA than EPA was deposited into the plaques. Whereas the increase of omega-3 fatty acids in plasma reached a plateau 3 weeks after initiation of fish oil feeding, a linear increase in plaque omega-3 fatty acids continued with time. As a result of the changes in fatty acid composition, the lipid classes of both plasma and plaque had a higher unsaturation index in the fish oil-fed group.(ABSTRACT TRUNCATED AT 250 WORDS)
Serum lipoprotein(a) in patients heterozygous for familial hypercholesterolemia, their relatives, and unrelated control populations.
Authors: Mbewu A D , Bhatnagar D , Durrington P N , Hunt L , Ishola M , Arrol S , Mackness M , Lockley P , Miller J P
Published: June 2011

Serum lipoprotein(a) (Lp[a]) levels were significantly higher in 89 patients with heterozygous familial hypercholesterolemia (FH) (geometric mean, 22.7 mg/dl) than in 109 normocholesterolemic controls (10.0 mg/dl, p less than 0.05) and 40 controls (9.1 mg/dl, p less than 0.05) with similarly elevated low density lipoprotein cholesterol levels due to other primary hypercholesterolemias. To provide further evidence that the increased serum Lp(a) concentration was due to inheritance of the FH gene, 24 unaffected first-degree relatives were compared with their FH probands. Serum Lp(a) in affected individuals was significantly greater than in unaffected relatives (geometric means, 26.5 versus 13.7 mg/dl, respectively; p less than 0.05). Family membership exerted an effect on serum Lp(a) concentrations, indicating that other genetic influences were also operating, as is known to be the case in general populations. Serum Lp(a) in 30 of the FH patients, who had coronary heart disease, was not significantly different from 30 age- and sex-matched controls with FH but with coronary heart disease (geometric means, 23.6 versus 24.7 mg/dl, respectively). FH is associated with an increase in serum Lp(a). Elevated serum Lp(a) concentrations should probably now be regarded as a component of the clinical syndrome of FH. However, within our FH population Lp(a) did not distinguish those with clinically overt coronary heart disease from those without the disease.
Lipoprotein receptors of HL-60 macrophages. Effect of differentiation with tetramyristic phorbol acetate and 1,25-dihydroxyvitamin D3.
Authors: Jouni Z E , McNamara D J
Published: June 2011

The human promyelocytic leukemic cell line HL-60 is a unique model for studies of the effects of macrophage differentiation on the expression and regulation of lipoprotein receptors. Undifferentiated HL-60 cells express a regulated low density lipoprotein (LDL) receptor and lack the acetylated LDL (acetyl-LDL) scavenger receptor. HL-60 macrophages differentiated with tetramyristic phorbol acetate failed to degrade LDL and acetyl-LDL via receptor-mediated processes. Differentiation with 1,25-dihydroxyvitamin D3 (D3) induced macrophages exhibiting specific saturable receptors for LDL and acetyl-LDL. The LDL receptor of D3-induced macrophages was found to exhibit specificity for apolipoprotein B- and E-containing lipoproteins, to be calcium dependent, and to be inhibited by pronase and chloroquine. Maximal degradation of acetyl-LDL was achieved within 2 days of D3 treatment and was specific for acetyl-LDL, was calcium independent, was inhibited by chloroquine, and was sensitive to pronase and fucoidin treatment. Incubation of D3-induced macrophages with LDL or acetyl-LDL resulted in reductions in sterol synthesis and receptor-mediated degradation of LDL; the scavenger receptor pathway was unaltered. These results demonstrate that D3-induced HL-60 macrophages exhibit patterns of sterol and lipoprotein metabolism and regulation that make them a useful model system for in vitro studies of lipoprotein-macrophage interactions related to foam cell development and atherogenesis.
Type III dyslipoproteinemia in patients heterozygous for familial hypercholesterolemia and apolipoprotein E2. Evidence for a gene-gene interaction.
Authors: Hopkins P N , Wu L L , Schumacher M C , Emi M , Hegele R M , Hunt S C , Lalouel J M , Williams R R
Published: June 2011

In four large pedigrees with heterozygous familial hypercholesterolemia (FH) genetically linked to the low density lipoprotein receptor locus, we have observed a strong interaction between the presence of FH and a single apolipoprotein (apo) E2 allele, resulting in a markedly increased prevalence of type III dyslipoproteinemia (DLPIII). DLPIII was defined by chemical criteria. None of the patients with DLPIII had tuberous or palmar xanthomas characteristic of classically defined type III hyperlipoproteinemia. After exclusion of four persons with apo E 2-2 phenotype, there were 89 FH patients and 110 non-FH subjects. Definite DLPIII (defined as a very low density lipoprotein [VLDL] cholesterol to plasma triglyceride ratio greater than 0.30 with plasma triglycerides greater than or equal to 150 mg/dl) was present in 26% of 43 FH patients with a single E2 allele compared with only 3.4% of 29 non-FH subjects with an E2 allele (p = 0.003). To further characterize this interaction we performed a two-way analysis of covariance, after adjustment for age, sex, and body mass index, to test for any interaction between FH and the apo E loci. There was a statistically significant interaction between FH and the presence of a single E2 allele for the ratio of VLDL cholesterol to plasma triglycerides and for a newly derived estimate of beta-VLDL cholesterol concentration. Estimated beta-VLDL cholesterol level was strongly correlated with age in the subgroup with FH and an E2 allele but not in other subgroups. There was no difference in estimated beta-VLDL cholesterol between sexes. Correlation between estimated beta-VLDL cholesterol level and body mass index in persons older than 18 years was of only marginal significance and of similar magnitude in persons with or without an apo E2 allele. Present knowledge suggests that beta-VLDLs are highly atherogenic; if so, then a sizable subset of FH patients having at least one apo E2 allele and DLPIII may be at increased risk for premature coronary heart disease.
Apolipoprotein E polymorphisms affect atherosclerosis in young males. Pathobiological Determinants of Atherosclerosis in Youth (PDAY) Research Group.
Authors: Hixson J E
Published: June 2011

Investigators in eight communities collected aortas, right coronary arteries, blood and liver samples, and associated information from 720 young males, aged 15-34 years, who died of external causes. Genotypes for apolipoprotein (apo) E isoforms (E2, E3, and E4) were determined from hepatic DNA by restriction isotyping (restriction enzyme isoform genotyping) of amplified apo E sequences. Pathologists graded the arteries for atherosclerotic lesions, and a central laboratory measured lipoprotein cholesterol concentrations. Allele frequencies were different between blacks and whites (p less than 0.0001). E2 and E4 frequencies were higher and E3 frequency was lower in blacks than in whites. Among the common genotypes in both whites and blacks, E2E3 heterozygotes had the lowest levels of total serum cholesterol and low density lipoproteins, E3E4 had the highest levels, and E3E3 had intermediate levels. Apo E genotypes differed in mean percent surface area involvement with lesions in the thoracic aorta and the abdominal aorta of both whites and blacks (p less than or equal to 0.0002). Among the common genotypes, E2E3 heterozygotes had the least involvement of both thoracic and abdominal aortas with lesions, E3E4 had the greatest involvement (with the exception of the thoracic aorta in whites), and E3E3 had intermediate involvement. Apo E genotype accounted for 5.7% in whites and 5.9% in blacks of the observed variation in lesions for the thoracic aorta, and for 5.9% in whites and 7.0% in blacks for the abdominal aorta. Adjusting for cholesterol levels did not change apo E genotypic effects appreciably, an observation suggesting that genotypic effects on arterial lesions may not be mediated entirely by changes in serum cholesterol concentrations.
Ultrasonographically assessed carotid morphology and the risk of coronary heart disease.
Authors: Salonen J T , Salonen R
Published: June 2011

As ultrasonographically assessed carotid arteriosclerosis is being used as a surrogate measure for coronary arteriosclerosis, we performed a prospective longitudinal study of the association of our high-resolution ultrasound assessment of extracranial carotid morphology with the risk of acute coronary events in 1,288 eastern Finnish men. The presence of any structural changes in the common carotid arteries or carotid bulbs was associated with a 3.29-fold (95% confidence interval, 1.31-8.29; p = 0.0074), intimal-medial thickening with a 2.17-fold (95% confidence interval, 0.70-6.74; p = NS), small carotid plaques with a 4.15-fold (95% confidence interval, 1.51-11.47; p less than 0.01), and large ("stenotic") plaques with a 6.71-fold (95% confidence interval, 1.33-33.91; p less than 0.01) risk of acute myocardial infarction compared with men free of any structural changes in the carotid artery wall at baseline. These data confirm the close relation between carotid artery wall morphology and coronary heart disease.
Interaction between variant apolipoproteins C-II and E that affects plasma lipoprotein concentrations.
Authors: Hegele R A , Breckenridge W C , Cox D W , Maguire G F , Little J A , Connelly P W
Published: June 2011

The genes for apolipoprotein (apo) C-II, a cofactor for activation of lipoprotein lipase, and apo E, a ligand for receptor-mediated uptake of triglyceride-rich lipoproteins, are physically linked on chromosome 19q13.1. In a large Caribbean Caucasian family, several individuals had clinical features of the complete absence of lipoprotein lipase activity and were homozygous for a DNA frameshift mutation of apo C-II, imparting functional inactivity to the mutant protein. Plasma from heterozygous carriers of this mutation, when compared with plasma from relatives who were noncarriers, had significantly diminished capacity to activate lipoprotein lipase in vitro. We also observed in heterozygotes for this mutation a wide range of serum lipid and lipoprotein levels. When age and sex were taken into account, the presence of a single apo E allele encoding the E4 isoform occurring in individuals with a single mutant apo C-II allele was strongly associated with higher levels of cholesterol, triglycerides, very low density lipoprotein cholesterol, and non-high density lipoprotein cholesterol when compared with those of relatives who carried neither or only one variant allele. This suggests that a single genetic mutation that usually has a recessive effect on lipoprotein metabolism can have an interactive effect on lipid phenotype when it is coinherited with a single mutation at another gene whose product affects the same metabolic pathway.
Effects of human recombinant macrophage colony-stimulating factor on the secretion of lipoprotein lipase from macrophages.
Authors: Mori N , Gotoda T , Ishibashi S , Shimano H , Harada K , Inaba T , Takaku F , Yazaki Y , Yamada N
Published: June 2011

The effects of human recombinant macrophage colony-stimulating factor (M-CSF) on the secretion of lipoprotein lipase were studied in rat alveolar macrophages. Five nanograms per milliliter M-CSF significantly enhanced lipoprotein lipase secretion (threefold), and the maximal effect (10-fold) of M-CSF on lipoprotein lipase secretion was observed at a dose of 200 ng/ml M-CSF. The effect of M-CSF was time dependent but was not manifested during the first 8 hours of incubation. After 24 hours, its effects were evident and dose dependent. On blot hybridization of macrophage RNAs with human cDNA of lipoprotein lipase, a remarkable and dose-dependent increase in mRNA level (7.3-fold) was found in M-CSF-treated alveolar macrophages. The secretion of lipoprotein lipase was also enhanced in human monocyte-derived macrophages (2.6-fold), whereas the secretion from either THP-1 cells, P388 cells, or J774 cells was not significantly enhanced. These results indicate that the stimulation of lipoprotein lipase secretion after M-CSF treatment was evident in rat alveolar macrophages and human monocyte-derived macrophages on the basis of both enzyme activity and mRNA level; therefore, M-CSF may be involved in lipoprotein metabolism of macrophages through modulation of the secretion of lipoprotein lipase.
Connective tissue proteinases and inhibitors in abdominal aortic aneurysms. Involvement of the vasa vasorum in the pathogenesis of aortic aneurysms.
Authors: Herron G S , Unemori E , Wong M , Rapp J H , Hibbs M H , Stoney R J
Published: June 2011

Recent studies have shown that increases in proteolytic activity are associated with abdominal aortic aneurysms (AAAs). We have studied samples of the dilated aortic wall, taken during corrective surgery for AAAs, in terms of the number, type, and tissue location of connective tissue proteinases and their inhibitors. Five distinct caseinolytic serine proteinases and six gelatinolytic metalloproteinases were resolved by molecular weight by use of sodium dodecyl sulfate-substrate gel electrophoresis. Isoforms of the Mr 92,000 neutrophil gelatinase were identified by immunoprecipitation of biosynthetically labeled organ culture media. About 50% of the total radiolabeled protein secreted by AAA organ cultures was identified as the Mr 30,000 glycoprotein, tissue inhibitor of metalloproteinase (TIMP), by immunoprecipitation. Both TIMP and gelatinase were localized to the vasa vasorum by immunoperoxidase staining. However, interstitial collagenase could not be detected by any method. These results suggest the involvement of the vasa vasorum in the maintenance and possibly the genesis of AAAs.