Effect of atorvastatin on plasma apoE metabolism in patients with combined hyperlipidemia

Atorvastatin, a synthetic HMG-CoA reductase inhibitor used for the treatment of hyperlipidemia and the prevention of coronary artery disease, significantly lowers plasma cholesterol and low-density lipoprotein cholesterol (LDL-C) levels. It also reduces total plasma triglyceride and apoE concentrations. In view of the direct involvement of apoE in the pathogenesis of atherosclerosis, we have investigated the effect of atorvastatin treatment (40 mg/day) on in vivo rates of plasma apoE production and catabolism in six patients with combined hyperlipidemia using a primed constant infusion of deuterated leucine. Atorvastatin treatment resulted in a significant decrease (i.e., 30-37%) in levels of total triglyceride, cholesterol, LDL-C, and apoB in all six patients. Total plasma apoE concentration was reduced from 7.4 +/- 0.9 to 4.3 +/- 0.2 mg/dl (-38 +/- 8%, P < 0.05), predominantly due to a decrease in VLDL apoE (3.4 +/- 0.8 vs. 1.7 +/- 0.2 mg/dl; -42 +/- 11%) and IDL/LDL apoE (1.9 +/- 0.3 vs. 0.8 +/- 0.1 mg/dl; -57 +/- 6%). Total plasma lipoprotein apoE transport (i.e., production) was significantly reduced from 4.67 +/- 0.39 to 3.04 +/- 0.51 mg/kg/day (-34 +/- 10%, P < 0.05) and VLDL apoE transport was reduced from 3.82 +/- 0.67 to 2.26 +/- 0.42 mg/kg/day (-36 +/- 10%, P = 0.057). Plasma and VLDL apoE residence times and HDL apoE kinetic parameters were not significantly affected by drug treatment. Percentage decreases in VLDL apoE concentration and VLDL apoE production were significantly correlated with drug-induced reductions in VLDL triglyceride concentration (r = 0.99, P < 0.001; r = 0.88, P < 0.05, respectively, n = 6). Our results demonstrate that atorvastatin causes a pronounced decrease in total plasma and VLDL apoE concentrations and a significant decrease in plasma and VLDL apoE rates of production in patients with combined hyperlipidemia.     

Effects of atorvastatin versus fenofibrate on apoB-100 and apoA-I kinetics in mixed hyperlipidemia

Kinetics of apo B and apo AI were assessed in 8 patients with mixed hyperlipidemia at baseline and after 8 weeks of atorvastatin 80 mg q.d. and micronised fenofibrate 200 mg q.d. in a cross-over study. Both increased hepatic production and decreased catabolism of VLDL accounted for elevated cholesterol and triglyceride concentrations at baseline. Atorvastatin significantly decreased triglyceride, total, VLDL and LDL cholesterol and apo B concentrations (-65%, -36%, -57%, -40% and -33%, respectively, P<0.05). Kinetic analysis revealed that atorvastatin stimulated the catabolism of apo B containing lipoproteins, enhanced the delipidation of VLDL1 and decreased VLDL1 production. Fenofibrate lowered triglycerides and VLDL cholesterol (-57% and -64%, respectively, P<0.05) due to enhanced delipidation of VLDL1 and VLDL2 and increased VLDL1 catabolism. Changes of HDL particle composition accounted for the increase of HDL cholesterol during atorvastatin and fenofibrate (18% and 23%, P<0.01). Only fenofibrate increased apo AI concentrations through enhanced apo AI synthesis (45%, P<0.05). We conclude that atorvastatin exerts additional beneficial effects on the metabolism of apo B containing lipoproteins unrelated to an increase in LDL receptor activity. Fenofibrate but not atorvastatin increases apo AI production and plasma turnover.     

Endothelial expression of endoglin in normocholesterolemic and hypercholesterolemic C57BL/6J mice before and after atorvastatin treatment

Endoglin (CD105) is a homodimeric transmembrane glycoprotein strongly related to transforming growth factor (TGF)-beta signaling and many pathological states. In this study, we wanted to evaluate whether endoglin is expressed in normocholesterolemic and hypercholesterolemic C57BL/6J mice as well as whether it is affected by atorvastatin treatment in these mice. C57BL/6J mice were fed with chow diet or an atherogenic diet for 12 weeks after weaning. In 2 atorvastatin-treated groups, mice were fed the same diets (chow or atherogenic) as described above except atorvastatin was added at the dosage of 10 mg x kg(-1) x day(-1) for the last 8 weeks before euthanasia. Biochemical analysis of blood samples revealed that administration of atherogenic diet significantly increased levels of total cholesterol, VLDL, LDL, and decreased levels of HDL. Atorvastatin treatment resulted in a significant decrease in total cholesterol and VLDL only in mice fed by atherogenic diet. Quantitative stereological analysis revealed that atorvastatin significantly decreased endothelial expression of endoglin in C57BL/6J mice fed the atherogenic diet. In conclusion, we demonstrated that endothelial expression of endoglin is upregulated by hypercholesterolemia and decreased by the hypolipidemic effect of atorvastatin in C57BL/6J mice, suggesting that endoglin expression could be involved in atherogenesis.     

Rapid isolation of VLDL subfractions: assessment of composition and susceptibility to copper-mediated oxidation

VLDLs, synthesized and released by the liver, are a heterogeneous group of particles of varying composition and metabolic fates. A method is described for the rapid isolation of VLDL into four subfractions (A-D) and assessment of their susceptibility to oxidation. The total isolation procedure required less than 3.5 h, and was achieved by gradient ultracentrifugation. Each subfraction was assessed for triglyceride, cholesterol, and apolipoprotein B (apoB) composition and for the presence of contaminants such as albumin and urate. The oxidation potential, in the presence of copper ions, of each subfraction was also assessed. This rapid procedure produced VLDL fractions analogous to those produced by a previously reported but more prolonged isolation method. Comparison of the two procedures demonstrated that lipid and apoB were similar, while the rapid procedure produced subfractions void of albumin and urate contamination and lower in preformed hydroperoxides. Compositional changes were found between the subfractions: as the subfractions became smaller and more dense (A-->D), there was a decrease in the ratio of triglyceride to apoB and an increase in the ratio of cholesterol to apoB, also arachidonic acid was increased in subfraction D compared with subfractions A, B, and C. The smaller subfractions were more susceptible to oxidation, a trend similar to that reported previously for the oxidation of LDL subfractions.     

Changes in plasma very low density and low density lipoprotein content, composition, and size after a fatty meal in normo- and hypertriglyceridemic man.

Four subfractions of plasma VLDL characterized by decreasing Sf value and LDL were isolated by density gradient preparative ultracentrifugation from normotriglyceridemic (NTG) and hypertriglyceridemic (HTG) (type IV) subjects in the fasting state and after a fatty meal. Chemical analysis and computation of numbers of particles in each fraction showed that the hyperlipidemia of type IV subjects was accounted for by an increase in total numbers of VLDL and a shift in the distribution of VLDL towards particles of larger diameter. Postprandial hyperlipidemia was due to the presence of chylomicron remnants rather than intact chylomicrons, and was accounted for by an increase in particle diameter of the largest VLDL subfraction rather than by an increase in particle numbers. Postprandial hyperlipedemia was accompanied by a shift in the distribution of VLDL towards particles of larger diameter in both NTG and HTG subjects, probably because of competition for the triglyceride-depletion process between chylomicrons and hepatic VLDL. Most chylomicron remnants were removed from the circulation without degradation to smaller VLDL or to LDL, but some remnants were sufficienty small to contribute to smaller VLDL subfractions. The LDL of type IV subjects contained more apoprotein B than those from NTG subjects, and this difference was associated with increases in diameter, molecular weight, density, and the ratio of protein: phospholipid in LDL from type IV subjects. Defective degradation of large VLDL to small VLDL, and of VLDL to LDL may be related to this alteration in apoprotein B content of the lipoproteins in type IV subjects.     

Structural heterogeneity of apoB-containing serum lipoproteins visualized using cryo-electron microscopy.

Cryo-electron microscopy was used to analyze the structure of lipoprotein particles in density gradient subfractions of human very low density lipoprotein (VLDL), intermediate density lipoprotein (IDL), and low density lipoprotein (LDL). Lipoproteins from a normolipidemic subject with relatively large and buoyant LDL (pattern A) and from a subject with a predominance of small dense LDL (pattern B) were compared. Projections of VLDL in vitreous ice were heterogeneous in size, but all were circular with a relatively even distribution of contrast. Selected projections of LDL, on the other hand, were circular with a high density ring or rectangular with two high density bands. Both circular and rectangular LDL projections decreased in average size with increasing subfraction density, but were found in all of 10 density gradient subfractions, both in pattern A and in pattern B profiles. Preparations of total IDL contained particles with the structural features of VLDL as well as particles resembling LDL. IDL particles resembling LDL were observed in specific density gradient subfractions in the denser region of the VLDL;-IDL density range. Within the group of IDL particles resembling LDL considerable heterogeneity was observed, but no structural features specific for the pattern A or pattern B lipoprotein profile were recognized.The observed structural heterogeneity of the apolipoprotein B-containing serum lipoproteins may reflect differences in the composition of these particles that may also influence their metabolic and pathologic properties.     

Increased atherosclerosis in diabetic dyslipidemic swine: protection by atorvastatin involves decreased VLDL triglycerides but minimal effects on the lipoprotein profile

Male Yucatan swine were allocated to four groups (n = 5-6 pigs per group): low fat (3%) fed control, high fat/2% cholesterol (CH) fed (HF), high fat/CH fed with alloxan-induced diabetes (DF) and DF pigs that were treated with atorvastatin (80 mg/day; DF+A). Pigs were fed two meals per day and daily insulin injections were used in diabetic pigs to maintain plasma glucose between 250 and 350 mg/dl. Diabetic dyslipidemic (DF) pigs exhibited greater coronary atherosclerosis and increased collagen deposition in internal mammary artery compared with normoglycemic hyperlipidemic pigs. Although total and LDL CH concentrations did not differ, triglyceride (TG) were increased in DF pigs and FPLC analysis indicated that the LDL/HDL CH ratio was significantly increased in DF compared with HF pigs. The LDL fraction of DF pigs contained larger, lipid enriched particles resembling IDL. Consumption of the high fat/CH diet caused a moderate increase in the percentage of 14:0 fatty acids in plasma lipids and this was compensated by small-moderate declines in several unsaturated fatty acids. There was a significant increase in phospholipid arachidonic acid in DF compared with HF pigs. Atorvastatin protected diabetic pigs from atherosclerosis and decreased total and VLDL TG, but exerted minimal effects on the FPLC lipoprotein and plasma fatty acid profiles and plasma concentrations of total and LDL CH, vitamin A, vitamin E, and lysophosphatidylcholine. Across all groups the plasma CH concentration was positively correlated with hepatic CH concentration. These findings suggest that atorvastatin's protection against coronary artery atherosclerosis in diabetes may involve effects on plasma VLDL TG concentration. Lack of major effects on other lipid parameters, including the LDL/HDL ratio, suggests that atorvastatin may have yet other anti-atherogenic effects, possibly directly in the vessel wall.     

Relation between insulin resistance and fast-migrating LDL subfraction as characterized by capillary isotachophoresis

The proportion of the electronegative low density lipoprotein [LDL(-)] subfraction, which is atherogenic, is increased in type 2 diabetes but is not reduced by glycemic control. Therefore, we evaluated the ability of a new technique, capillary isotachophoresis (cITP), to quantify charge-based LDL subfractions and examined the relation between insulin resistance and the cITP fast-migrating (f) LDL levels. Seventy-five 10-year-old boys were included. The two cITP LDL subfractions, fLDL and major LDL subfractions, were proportional to the LDL protein content within the range of 0.1-0.8 mg/ml LDL protein. Levels of cITP fLDL were positively correlated with triglyceride (TG) levels and negatively correlated with LDL size. Insulin resistance as assessed by the homeostasis model assessment (HOMA-IR) was positively correlated (P < 0.01) with cITP fLDL levels (r = 0.41). The relation between HOMA-IR and cITP fLDL levels depended on TG levels but was independent of body mass index and LDL size. cITP lipoprotein analysis is an accurate and sensitive method for quantifying charge-based LDL subfractions in human plasma, and insulin resistance is related to cITP fLDL independent of LDL size.     

Mechanisms Underlying Early-Stage Changes in Visual Performance and Retina Function After Experimental Induction of Sustained Dyslipidemia

Visual and retinal function was measured in a mouse model of chemically induced, sustained dyslipidemia to determine the contribution of dyslipidemia to the pathogenesis of retinopathy in the context of metabolic syndrome. Fifteen male C57BL/6Crl mice were divided into three groups. Poloxamer 407 (P-407), 14.5% w/w was delivered at a rate of 6 µl/day by implanted osmotic mini-pumps either subcutaneously (P-407 SQ) or intraperitoneally (P-407 IP) to P-407-treated mice, whereas saline was administered at the same rate to control mice using only the subcutaneous route of administration. Total cholesterol (TC) and true triglyceride (TG) levels were quantified from plasma. Optomotor responses to stimuli of varying spatial frequency or contrast were used to measure visual acuity and contrast sensitivity. Retinal function was determined using Ganzfeld flash electroretinography (ERG). At 32?days, TC for the P-407 IP group was significantly elevated compared to saline controls (169.4?±?16.5 mg/dl, 0.001?<?P?<?0.01). TG levels for both the P-407 SQ (59.3?±?22.4 mg/dl, 0.01?<?P?<?0.05) and P-407 IP groups (67.7?±?18.0 mg/dl, 0.001?<?P?<?0.01) were significantly elevated relative to controls. Electroretinography demonstrated a very significant decline in the b/a ratio (1.80?±?0.11, P?<?0.01) for the P-407 IP group. The b/a ratio exhibited a moderate, significant correlation with TC levels (r?=???0.4425, P?=?0.0392) and a strong, very significant correlation with TG levels (r?=???0.6190, P?=?0.0021). Delivery of P-407 via osmotic mini-pump resulted in the sustained, significant elevation of plasma TC and TG levels. This elevation in plasma lipid levels was correlated with a decline in inner retinal function.     

Very low density and low density lipoprotein subfractions in type III and type IV hyperlipoproteinemia. Chemical and physical properties.

Subfractions of CLDL (VLDL), Sf 100-400; CLDL2, Sf 60--100; VLDL3, Sf 20--60) and LDL (LDL), Sf 12--20; LDL2, Sf 6--12; LDL3, Sf 3--6) were isolated from the plasma of three normal, three type III and four type IV hyperlipoproteinemic subjects. In the type IV group, all VLDL subspecies were of normal composition but were increased in concentration in the order VLDL1 greater than VLDL2 greater than VLDL3. In the same subjects, although LDL2 was lowered and LDL3 increased, the total plasma LDL concentration was normal. All VLDL subfractions were elevated in the type III group, but in this case VLDL3 predominated. These subfractions were enriched in cholesteryl esters and depleted in triglyceride. In the LDL density range there was a shift of mass towards the least dense fraction, LDL1, which was of normal composition. EPR studies of the VLDL and LDL subfractions in a type IV subject demonstrated a decrease in fluidity with increasing density. The major change occurred between VLDL3 and LDL1 and was attributed to a substantial alteration in the cholesteryl ester : triglyceride ratio in the particle. A similar argument was used to explain thction in normal or type IV subjects. Particle diameters, determined by laser light-scattering spectroscopy were in good agreement with the values obtained by electron microscopy. This study provides a baseline for the examination of the relationship between the physical and metabolic properties of VLDL and LDL subfractions in type III and IV hyperlipoproteinemia.     

Dietary carbohydrate and cholesterol influence the number of particles and distributions of lipoprotein subfractions in guinea pigs

Guinea pigs (n=10/group) were fed one of three diets: a high carbohydrate (CHO) (42% energy), low cholesterol (0.04%) diet (LChHC), a diet with the same amount of CHO but with 0.25% cholesterol (HChHC) or a diet with 11% of energy from CHO and 0.25% cholesterol (HChLC) for 12 weeks. VLDL- and LDL cholesterol (LDL-C) were higher in the HChLC and HChHC groups than in the LChHC group (P<.0001). Lipoprotein subclasses and size were analyzed by nuclear magnetic resonance. Dietary cholesterol (HChHC and HChLC groups) resulted in larger VLDL particles (71.1+/-6.9, 78.9+/-3.33 nm, respectively) than those in the LChHC group (44.3+/-10.8 nm). In addition, there were higher concentrations of the large VLDL (>60 nm) and the medium VLDL (>35 nm) in the high cholesterol groups (P<.01). Similarly, the concentration of the medium (>8.2 nm) and small HDL (>7.2 nm) was higher in the HChHC and HChLC groups (P<.001). In contrast, CHO restriction affected the concentrations of LDL subfractions. The number of total LDL particles was lower in the HChLC (291.3+/-85.0 nmol/L) than in the HChHC group (467.6+/-113.1 nmol/L), indicating that the cholesterol in LDL was distributed in less particles in the former group. The concentrations of medium LDL (>19.8 nm) (98.4+/-90.8) and small LDL (>18 nm) (29.3+/-24.9 nmol/L) were lower in the HChLC group than in the HChHC group (261.8+/-105.8 and 64.9+/-27.9 nmol/L, respectively). These results indicate that dietary cholesterol increased the atherogenicity of both VLDL and HDL while CHO restriction increased the number of large LDL and decreased the concentrations of the more atherogenic smaller LDL subfractions.     

A comparison of anion-exchange and steric-exclusion HPLC assays of mouse plasma lipoproteins

We compared two HPLC methods (anion exchange [AE] and steric exclusion [SE]) for analysis of mouse lipoprotein profiles by determining coefficients of variability (CVs) under varying conditions. CVs for AE and SE were comparable on fresh samples. There was an inverse relationship between subfraction curve area and CV [r = -0.65 (AE) and -0.50 (SE)], consistent with the interpretation that as curve area decreased, error variance increased and signal-to-noise ratio decreased. Sample storage did not affect SE. In contrast, with AE, alterations in measured lipoproteins were apparent after storage, including a decrease in the HDL subfraction [66.8% (baseline) vs. 15.9% (1 week); P < 0.01] and an increase in areas under LDL and VLDL peaks. Concomitant with decreasing HDL area, reproducibility deteriorated with the duration of storage. Analysis of the effects of decreasing sample injectate volume to <25 microl on SE lipoprotein subfractions revealed that areas under LDL and VLDL peaks decreased and persisted as volume was decreased further. Areas under all lipoprotein subfractions measured with either AE or SE were linearly correlated with the amount of cholesterol [r = 0.69 (AE) and 0.87 (SE)]. Both AE and SE yield reproducible, accurate, and rapid measurements of lipoproteins from small amounts of serum. AE yields more sensitive, high-amplitude, well-defined peaks that can be easily distinguished and necessitates the use of smaller sample volumes compared with SE, but sample storage causes alterations in the chromatogram. SE appears better suited to serial analyses involving stored samples.     

Characterization and metabolic fate of two very-low-density lipoprotein subfractions separated by heparin-sepharose chromatography

Human very-low-density lipoproteins (VLDL) have been separated into two discrete subfractions by heparin-Sepharose chromatography. The retained fraction relative to the unretained fraction is characterized by an increased cholesterol ester/triacylglycerol ratio and an increased ratio of apolipoprotein E relative to apolipoprotein C. We have subfractionated VLDL from type IV hyperlipoproteinemic subjects and characterized these subfractions with respect to (i) composition and (ii) the metabolic fate of apolipoprotein B of each subfraction. The unretained fraction accounted for an average of 42% of total VLDL in type IV subjects. A similar distribution was obtained with VLDL from Type III subjects; however, only 25% of normal VLDL is in the unretained fraction. The apolipoprotein E/apolipoprotein C ratio was 2-8-fold higher in the retained fraction. The distribution of apolipoprotein E isomorphs and the individual C apolipoproteins were similar in each fraction. Retained and unretained fractions were labelled with 125I and/or 131I and injected simultaneously into miniature pigs. Apolipoprotein B of retained fractions was catabolized at a greater rate (fractional catabolic rate = 0.98 h-1 vs. 0.54 h-1, n = 7, P less than 0.05) compared to unretained fractions. These results are consistent with the concept that reduced content of C apolipoproteins in VLDL is correlated with enhanced uptake by perfused rat livers. Apolipoprotein B from retained fractions was converted to intermediate-density lipoproteins (IDL) at a greater rate, and apolipoprotein B from both fractions were converted to low-density lipoproteins (LDL). Although the unretained fraction may be the precursor of the retained fraction, the possibility exists that each fraction is largely synthesized and catabolized independently.     

Lipid transfer inhibitor protein defines the participation of high density lipoprotein subfractions in lipid transfer reactions mediated by cholesterol ester transfer protein (CETP)

Cholesterol ester transfer protein (CETP) moves triglyceride (TG) and cholesteryl ester (CE) between lipoproteins. CETP has no apparent preference for high (HDL) or low (LDL) density lipoprotein as lipid donor to very low density lipoprotein (VLDL), and the preference for HDL observed in plasma is due to suppression of LDL transfers by lipid transfer inhibitor protein (LTIP). Given the heterogeneity of HDL, and a demonstrated ability of HDL subfractions to bind LTIP, we examined whether LTIP might also control CETP-facilitated lipid flux among HDL subfractions. CETP-mediated CE transfers from [3H]CE VLDL to various lipoproteins, combined on an equal phospholipid basis, ranged 2-fold and followed the order: HDL3 > LDL > HDL2. LTIP inhibited VLDL to HDL2 transfer at one-half the rate of VLDL to LDL. In contrast, VLDL to HDL3 transfer was stimulated, resulting in a CETP preference for HDL3 that was 3-fold greater than that for LDL or HDL2. Long-term mass transfer experiments confirmed these findings and further established that the previously observed stimulation of CETP activity on HDL by LTIP is due solely to its stimulation of transfer activity on HDL3. TG enrichment of HDL2, which occurs during the HDL cycle, inhibited CETP activity by approximately 2-fold and LTIP activity was blocked almost completely. This suggests that LTIP keeps lipid transfer activity on HDL2 low and constant regardless of its TG enrichment status. Overall, these results show that LTIP tailors CETP-mediated remodeling of HDL3 and HDL2 particles in subclass-specific ways, strongly implicating LTIP as a regulator of HDL metabolism.     

Reduction in hepatic non-esterified fatty acid concentration after long-term treatment with atorvastatin lowers hepatic triglyceride synthesis and its secretion in sucrose-fed rats

The mechanism by which atorvastatin lowers plasma triglyceride (TG) levels is mainly through a decrease in hepatic TG secretion. However, it is not clear why atorvastatin, which does not inhibit TG synthesis in vitro, decreases hepatic TG secretion without a prospective increase in hepatic TG concentration. For the investigation of the mechanisms that underlie the hypotriglyceridemic effects of atorvastatin, we characterized the effect of either a single or an 11 day administration of atorvastatin in sucrose-induced hypertriglyceridemic rats. Atorvastatin (30 mg/kg p.o.) strongly decreased the rate of both very-low-density lipoprotein (VLDL)-TG and VLDL-apolipoprotein B secretion. The inhibitor also decreased hepatic TG concentration. Hepatic TG synthesis activity was also decreased by atorvastatin, and its activity was correlated with both hepatic and plasma TG concentration. There was also a strong correlation between the hepatic TG synthesis and hepatic non-esterified fatty acid (NEFA) concentration (r(2)=0.815). These effects required chronic administration of the inhibitor and were not observed by acute treatment. Repeated administration of atorvastatin also strongly reduced hepatic acyl-coenzyme A synthase mRNA levels. These results suggest that the reduced hepatic NEFA most likely lowers hepatic TG synthesis and TG secretion in sucrose-fed hypertriglyceridemic rats.     

Determining hepatic triglyceride production in mice: comparison of poloxamer 407 with Triton WR-1339

Triglyceride (TG), a water-insoluble energy-rich lipid, is secreted by the liver as part of very low density lipoproteins (VLDLs) to supply energy to extrahepatic tissues. Overproduction of VLDL is associated with increased risk of cardiovascular heart disease; this has renewed an interest in factors that affect hepatic TG production. The TG production rate is determined by measuring temporal increases in plasma TG under conditions in which TG hydrolysis by lipoprotein lipase (LPL) is inhibited. The nonionic detergent, Triton WR-1339 (Triton), has commonly been used to inhibit LPL for this purpose. Triton, in addition to inhibition of TG hydrolysis, has properties that have the potential to adversely influence lipoprotein metabolism. Another nonionic detergent, poloxamer 407 (P-407), also inhibits LPL. In these studies, we demonstrate that P-407 is comparable to Triton in the determination of TG production but without the unwanted side effects of Triton.     

Genetic determinants of risk factors for cardiovascular disease in a population from rural Brazil

We investigate the heritability of and pleiotropic relationships among triglycerides and cholesterol lipoproteins that have long been considered traditional risk factors for cardiovascular disease. Quantitative lipid and lipoprotein phenotypes were determined for a cross-sectional sample of a community in Jequitinhonha valley in northern Minas Gerais state, Brazil. The sample consisted primarily of subsistence farmers. Two hundred sixty-nine individuals (128 males and 141 females), ages 18-88 years, were sampled. Eighty-eight percent (n = 252) of the individuals belonged to a single pedigree, which was highly informative for genetic analysis. Data on anthropometrics, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total cholesterol, and triglycerides were available for each study participant. Extended pedigrees were constructed using the pedigree-based data management software PedSys. Univariate and bivariate variance-components analyses, adjusted by sex and age, were performed using the SOLAR software package. Heritability estimates of lipids and lipoproteins ranged from 29% to 45% (p < 0.008). The highest heritability estimated was for HDL-C (h2 = 44.8%, p < 0.0001), and this was the only trait that exhibited a significant household effect (c2 = 25%). Strong positive genetic correlations were found between triglycerides and very low density lipoprotein (VLDL) (rhog = 0.998) and between total cholesterol and LDL-C (rhog = 0.948). Significant genetic correlations were also found between triglycerides and LDL-C, between total cholesterol and VLDL, and between total cholesterol and LDL-C and VLDL, and finally between LDL and VLDL. There was a significant negative environmental correlation between triglycerides and HDL-C (rhoe = -0.406).     

强化阿托伐他汀治疗对ACS患者血脂水平的短期影响

目的:观察强化阿托伐他汀治疗对急性冠脉综合征(ACS)患者血脂水平的短期影响。方法:收集100例ACS患者,入院当天(the day of admission,D0)、入院第一天(the first day,D1)及入院第二天(The Second Day,D2)分别给予阿托伐他汀80mg治疗,入院D0立即采血化验血脂参数包括总胆固醇(total cholesterol,TC)、低度脂蛋白(LDL-cholesterol,LDL-C)、高密度脂蛋白(HDL-cholesterol,HDL-C)、甘油三酯(triglycerides,TG),分别在D1和D2晨起空腹复查。结果:总胆固醇的平均基线水平为5.24±0.07(D0),低密度脂蛋白为3.26±0.07,高密度脂蛋白胆固醇为1.07±0.07,甘油三酯为1.31±0.07。口服阿托伐他汀80毫克后第一天早晨,TC水平下降6.1%(D1)(与D0相比P0.001),第二日下降13.2%(D2)(与D0相比P0.001),LDL-C下降5.8%(D1)(DO与D1相比,P0.001)和15.6%(D2)(DO与D2相比,P0.001);HDL-C下降7.5%(D1)(DO与D1相比,P0.001)和12.1(D2)(DO与D2相比,P0.001);相反TG水平升高20.6%(D1)(DO与D1相比,P0.001)和25.5%(D2)(DO与D2相比,P0.001)。结论:强化他汀治疗对ACS患者血脂短期的影响与长期的影响是不同的,TC,LDL和HDL在短期内是下降的,而TG是升高的。     

Single spin density gradient ultracentrifugation method for the detection and isolation of light and heavy low density lipoprotein subfractions

A single spin density gradient ultracentrifugation method in a swinging bucket rotor has been applied for the detection and isolation of low density lipoprotein (LDL) subfractions. The visualization of the LDL heterogeneity was facilitated by prestaining the serum with Coomassie Brilliant Blue R prior to density gradient ultracentrifugation for 19.5 hr. A total of 13 human serum pools was analyzed. In each pool, two LDL subfractions, a lighter LDL1 subfraction, occasionally showing a subdivision into two bands, LDL1A and LDL1B, and a heavier LDL2 could be clearly distinguished by the banding pattern in the density gradient. Physicochemical characteristics of the isolated LDL subfractions were determined. The simple method for detection and isolation of these subfractions presented here may facilitate future studies on LDL heterogeneity.     

A study of the copper-binding proteins in liver and kidney tissue of neonatal normal and mottled mutant mice.

The Cu2+-binding proteins from liver and kidney tissue of 7--8-day-old brindled (Mobr) mice and their normal littermates were compared. (1) Separation over Bio-Gel P-10 showed that the differences in the Cu2+ content of mutant tissues were largely associated with a low-molecular-weight protein fraction (mol.wt. 14 500). (2) Further purification of this low-molecular-weight fraction by anion-exchange chromatography revealed four subfractions. The Cu2+ content of each subfraction reflected the Cu2+ status of the tissue of origin; the Cu2+ contents of the mutant kidney subfractions were elevated and those of the mutant liver were depressed compared with normal. In contrast, the protein contents of the subfractions were less variable and did not reflect the differing Cu2+ contents. (3) Amino acid analysis of the four subfractions from CuCl2-treated mutant and normal animals revealed clos similarities. The proteins showed high glycine, glutamic acid, serine, alanine and lysine contents and a rather variable cysteine content. Differences were apparent in the normal liver subfractions, which showed a higher cysteine content and lower glutamic acid content than did either the mutant liver or normal and mutant kidney subfractions. These observations, together with the recorded presence of aromatic amino acids, indicated that these proteins are not thioneins.