Effect of alcohol intake on human apolipoprotein A-I-containing lipoprotein subfractions

High-density lipoprotein comprises two main types of lipoprotein particles: (1) those that contain apolipoproteins A-I and A-II, designated LpA-I:A-II, and (2) those that contain apolipoprotein A-I but not apolipoprotein A-II, designated LpA-I. Both have been extensively studied and are believed to represent distinct metabolic entities that may confer differing protection against coronary artery disease risk. We have previously suggested that LpA-I might represent the antiatherogenic effect, which has been ascribed mainly to its effect on high-density lipoprotein cholesterol; we set out to investigate, in 344 men, the relation between LpA-I:A-II and LpA-I levels and alcohol consumption. As the alcohol intake rose, LpA-I:A-II levels increased, while LpA-I levels fell. On the assumption that LpA-I is the antiatherogenic fraction of high-density lipoprotein, the putative protective action of alcohol consumption against coronary artery disease should be reconsidered.     

Changes in serum apolipoprotein and lipoprotein profile after alcohol withdrawal: effect of apolipoprotein E polymorphism

BACKGROUND: Apolipoprotein (Apo) E genotype and alcohol consumption or withdrawal strongly affect lipoprotein (Lp) metabolism and, as with any genetic and environmental factors, they might interact. The aim of this study was to investigate this gene/environment interaction by analyzing the effect of the apoE genotype on the alcohol withdrawal-induced alterations in the serum Apo and Lp profile. METHODS: ApoE genotypes and concentrations of serum cholesterol, triglyceride, and Lps containing apoA-I, A-II, B, E, and C-III were determined in 84 male alcohol abusers before and after 3 weeks of abstinence. RESULTS: After withdrawal, concentrations of serum apoA-I, LpA-I, LpA-I/A-II, apoC-III, LpC-III-non-B, apoE, and LpE-non-B significantly decreased, whereas those of triglycerides and apoB increased; levels of cholesterol, LpC-III:B, and LpB:E were not affected. ANOVA shows that apoE polymorphism effects were quite similar before and after alcohol withdrawal on all serum Apos and Lps (the interaction term between withdrawal and apoE genotype was not significant). The only interaction term that was borderline significant (p < or = 0.10) concerned the apoB concentration. Before withdrawal, no association between apoB level and apoE polymorphism was observed, whereas after abstinence, a borderline significant (p < or = 0.10) gradient of concentration across the three groups of subjects (epsilon2 carriers < epsilon3/epsilon3 < epsilon4 carriers) was noticed. CONCLUSIONS: Alcohol abstinence causes major changes in the antiatherogenic Apos and Lps and may increase those known to be atherogenic. Heavy alcohol consumption seems to alter the effect of apoE polymorphism on apoB levels, and further investigations are needed to clarify the mechanisms involved in this phenomenon: a defect in sialylation of apoE, formation of acetaldehyde adducts on apoB, or both.     

Binding of transition metals by apolipoprotein A-I-containing plasma lipoproteins: inhibition of oxidation of low density lipoproteins.

We have found transition metals tightly bound to apolipoprotein A-I-containing lipoproteins [Lp(A-I)] isolated by selected affinity immunosorption from human serum. Prominent among the metal ions detected were iron and copper. By immunoblotting the proteins of Lp(A-I), we detected both transferrin and ceruloplasmin. The transferrin-containing Lp(A-I) particles, isolated by selected affinity immunosorption against transferrin, were larger (mean diameter of 14.2 nm) and had a higher protein content than most high density lipoproteins (HDL). Ultracentrifugally isolated HDL were found to contain much less transferrin, whereas transferrin was found associated with apolipoprotein A-I from the greater than 1.21-g/ml ultracentrifugal fraction. This suggests that the complex is not recovered in the classic HDL density interval because of its very high density. HDL inhibit copper-catalyzed oxidation of low density lipoproteins (LDL) in vitro. We have found that immunoisolated Lp(A-I) are an order of magnitude more effective in inhibiting the oxidation of LDL than ultracentrifugally isolated HDL, on the basis of protein mass. When the Lp(A-I) particles containing transferrin and ceruloplasmin were removed from the bulk of Lp(A-I), inhibition of the in vitro oxidation of LDL was significantly decreased.     

N-acetylcysteine and serum concentrations of lipoprotein(a).

A high plasma concentration of lipoprotein(a) [Lp(a)], a complex of low-density lipoprotein linked by disulphide bridges to apoprotein(a), is correlated with premature atherosclerosis. We determined whether the serum Lp(a) concentration could be decreased in vitro and in vivo by the reducing agent N-acetylcysteine (NAC), a drug used as a mucolytic agent, which acts by cleaving disulphide bonds. High concentrations of NAC (greater than or equal to 8 mg ml-1) resulted in dissociation of the Lp(a) antigen in vitro. However, the plasma level of Lp(a) was not changed by administration of NAC 1.2 g d-1 for 4 weeks in 7 subjects with a median Lp(a) concentration of 14.3 mg dl-1 (range 2.1-21.0 mg dl-1) or by doubling the dose to 2.4 g d-1 for a further 2 weeks. In 12 subjects with a high plasma level of Lp(a), median 87.0 mg dl-1 (range 42.0-201.6 mg dl-1), a small but significant decrease in Lp(a) concentration of 7% (P = 0.02) was observed after administration of NAC in a dose of 1.2 g d-1 for 6 weeks. These results indicate that NAC has only a limited capacity to reduce the concentration of Lp(a), which is not clinically significant.     

载脂蛋白E基因多态性与健康人群血脂谱改变的关系

目的 :研究载脂蛋白E(apoE)基因多态性与健康人群血脂谱改变的关系。方法 :随机选择 16 8例江苏地区无血缘关系健康汉族人群 ,用聚合酶链反应 限制性片段长度多态性技术检测其apoE基因型。分析各基因型及等位基因对血脂、载脂蛋白及脂蛋白 (a)的影响。结果 :apoE各等位基因血清总胆固醇 (TC)、低密度脂蛋白胆固醇 (LDL C)及apoB水平由高到低依次为ε4 >ε3>ε2 。ε2 等位基因具有明显的降低TC、LDL C和apoB的作用 ;而ε4 等位基因的作用正相反。结论 :apoE基因多态性是个体间血脂谱差异的独立遗传因素。     

The effect of apolipoprotein E genotype on serum lipoprotein particle response to exercise

Exercise affects lipoprotein metabolism and apolipoprotein E (Apo E) genotype may alter changes in lipoprotein subclasses that occur with exercise. The present study examined the effects of Apo E genotype (APOE) on the response of lipoprotein subclass concentrations to long-term exercise. A prospective longitudinal study, conducted at seven centers, genetically screened 566 individuals to create three cohorts of healthy adults, equal for gender and the most common APOE variants: E2/3 (n = 35), E3/3 (n = 40), and E3/4 (n = 31). Subjects with body mass index (BMI) > or = 31 or evidence of dyslipidemia or metabolic disease were excluded. All subjects exercised aerobically at 75% of maximal heart rate for 40 min, four times weekly for 6 months. Fasting lipoprotein subpopulations were measured before and after exercise training using proton nuclear magnetic resonance spectroscopy. Serum lipids for the entire cohort did not change with exercise training, but the LDL subpopulation response varied by APOE. Small-sized LDL particles decreased only in the APOE3 homozygotes whereas medium-sized LDL particles increased only in this group. These changes were directionally different from the responses in the E2/3 and E3/4 subjects (p < 0.05). Neither exercise nor APOE variant affected overall LDL or HDL size or cholesterol concentration, but exercise decreased VLDL diameter by 3.5 nm (p < 0.001) attributable to decreases in large VLDL in each APOE group. In conclusion, APOE variants influence the serum LDL subpopulation response to exercise training in normolipidemic subjects. Subjects homozygous for APOE3 experienced the most beneficial lipid effects from exercise training.     

The metabolism of lipoprotein(a) and other apolipoprotein B-containing lipoproteins: a kinetic study in humans

Lipoprotein(a) is a risk factor for cardiovascular disease composed of an apolipoprotein B-containing lipoprotein to which a second protein, apolipoprotein(a), is attached. We investigated in seven subjects with Lp(a) levels of 39--85 mg/dl the metabolism of four apo B-containing lipoproteins (VLDL(1), VLDL(2), IDL and LDL) together with that of apo B and apo(a) isolated from Lp(a). Rates of secretion, catabolism and where appropriate, transfer were determined by intravenous administration of d(3)-leucine, mass spectrometry for measurements of leucine tracer/tracee ratios and kinetic data analysis using multicompartmental metabolic modeling. Apo B in Lp(a) was secreted at a rate of 0.28 (0.17--0.40) mg/kg per day. It was found to originate from two sources -- 53% (43--67) were derived from preformed lipoproteins, i.e. IDL and LDL, the remainder was accounted for by apo B, directly secreted by the liver. The fractional catabolic rates (FCRs) of apo B and of apo(a) prepared from Lp(a) were determined as 0.27 (0.16--0.38) and 0.24 (0.12--0.40) pools per day, respectively, which is less than half of the FCR observed for LDL. Our in vivo data from humans support the view that Lp(a) assembly is an extracellular process and that its two protein components, apo(a) and apo B, are cleared from the circulation at identical rates.     

Effect of alcohol intake and exercise on plasma high-density lipoprotein cholesterol subfractions and apolipoprotein A-I in women

Abstinence from alcohol consumption for 3 weeks was followed by 3 weeks of wine intake in 18 inactive and 18 physically active premenopausal women (runners). The runners weighed less and had higher plasma high-density lipoprotein (HDL) cholesterol and lower low-density lipoprotein cholesterol levels than the inactive women. There were no differences between groups in plasma total cholesterol, triglyceride and apolipoprotein A-I concentrations. Runners had higher plasma HDL2 cholesterol concentrations than inactive women (34 +/- 17 vs 19 +/- 12 mg/dl), but HDL3 cholesterol concentration did not differ between the groups (41 +/- 10 vs 39 +/- 9 mg/dl). Addition of 35 g/day of ethanol for 3 weeks did not result in a significant change in either group for any of the variables measured. The amount of exercise appears to be a more important determinant of plasma lipoproteins and apolipoprotein A-I than alcohol intake in premenopausal women.     

Associations among serum lipoprotein(a) levels, apolipoprotein(a) phenotypes, and myocardial infarction in patients with extremely low and high levels of serum lipoprotein(a).

A high serum lipoprotein(a) [Lp(a)] level, which is genetically determined by apolipoprotein(a) [apo(a)] size polymorphism, is an independent risk factor for coronary atherosclerosis. However, the associations among Lp(a) levels, apo(a) phenotypes, and myocardial infarction (MI) have not been studied. Patients with MI (cases, n = 101, M/F: 86/15, age: 62+/-10y) and control subjects (n = 92, M/F: 53/39, age: 58+/-14y) were classified into quintile groups (Groups I to V) according to Lp(a) levels. Apo(a) isoform phenotyping was performed by a sensitive, high-resolution technique using sodium dodecyl sulfate-agarose/gradient polyacrylamide gel electrophoresis (3-6%), which identified 26 different apo(a) phenotypes, including a null type. Groups with higher Lp(a) levels (Groups II, III, and V) had higher percentages of MI patients than that with the lowest Lp(a) levels (Group I) (54%, 56%, or 75% vs. 32%, p<0.05). Groups with different Lp(a) levels had different frequency distributions of apo(a) isoprotein phenotypes: Groups II, III, IV, and V, which had increasing Lp(a) levels, had increasingly higher percentages of smaller isoforms (A1-A4, A5-A9) and decreasingly lower percentages of large isoforms (A10-A20, A21-A25) compared to Group I. An apparent inverse relationship existed between Lp(a) and the apo(a) phenotype. Subjects with the highest Lp(a) levels (Group V) had significantly (p<0.05) higher serum levels of total cholesterol, apo B, and Lp(a). Patients with MI and the controls had different distributions of apo(a) phenotypes: i.e., more small isoforms and more large size isoforms, respectively (A1-A4/A5-A9/A10-A20/A21-A25: 35.7%/27.7%/20.8%/15.8% and 22.8%/23.9%/29.4%/23.9%, respectively). Lp(a) (parameter estimate +/- standard error: 0.70+/-0.20, Wald chi2 = 12.4, p = 0.0004), apo(a) phenotype (-0.43+/-0.15, Wald chi2 = 8.17, p = 0.004), High-density lipoprotein-cholesterol, apo A-I, and apo B were significantly associated with MI after adjusting for age, gender, and conventional risk factors, as assessed by a univariate logistic regression analysis. The association between Lp(a) and MI was independent of the apo(a) phenotype, but the association between the apo(a) phenotype and MI was not independent of Lp(a), as assessed by a multivariate logistic regression analysis. This association was not influenced by other MI- or Lp(a)-related lipid variables. These results suggest that apo(a) phenotype contributes to, but does not completely explain, the increased Lp(a) levels in MI. A stepwise logistic regression analysis with and without Lp(a) in the model identified Lp(a) and the apo(a) phenotype as significant predictors for MI, respectively.     

Treatment of hypothyroidism reduces low-density lipoproteins but not lipoprotein(a).

Lipoprotein(a) [Lp(a)] is a low-density lipoprotein (LDL) particle in which apolipoprotein B-100 (apo B) is attached to a large plasminogen-like protein called apolipoprotein(a) [apo(a)]. Apo(a) has several genetically determined phenotypes differing in molecular weight, to which Lp(a) concentrations in plasma are inversely correlated. LDL and apo B levels are often elevated in untreated hypothyroidism and lowered by thyroxine (T4) treatment, probably due to an increase in LDL receptors. We measured plasma concentrations of LDL, apo B, and Lp(a) in 13 patients with symptomatic primary hypothyroidism before and during T4 therapy. The mean concentration of LDL decreased significantly (P = .006) from 6.05 mmol/L to 4.07 mmol/L, and the mean concentration of apo B decreased significantly (P = .005) from 1.42 g/L to 1.12 g/L. Median Lp(a) concentrations remained unchanged (P = .77); they were 17.05 mg/dL before and 16.59 mg/dL during T4 treatment. In both the untreated condition and during substitution therapy, Lp(a) levels were higher in patients than in healthy controls, probably due to a relatively high frequency of the small Lp(a) phenotypes in our patients. Since Lp(a) contains apo B, which is a ligand for the LDL receptor, it is surprising that Lp(a) is not reduced along with LDL and apo B. These findings suggest that the catabolism of LDL and Lp(a) differ in some respect, and that thyroid hormones have little, if any, effect on Lp(a).     

脂蛋白(a)与其他脂蛋白和载脂蛋白相关性研究

目的探讨冠心病患者血浆脂蛋白(a)与HDL-C、LDL-C、载脂蛋白(apo)A-Ⅰ、apoB的相关性,评价血脂异常与冠心病的相关性。方法选择因胸痛入院的患者1011例,经冠状动脉造影确诊为冠心病患者613例作为冠心病组,非冠心病患者398例作为对照组。测定脂蛋白(a)、apoA-Ⅰ、apoB、HDL-C和LDL-C,进行相关性分析,并计算apoB/apoA-Ⅰ比值。结果冠心病组的脂蛋白(a)、LDL-C及apoB水平较对照组明显升高(P=0.000);冠心病组脂蛋白(a)水平与LDL-C、apoB呈显著正相关(r=0.135、r=0.168,P0.01),与HDL-C、apoA-Ⅰ无相关性。对照组脂蛋白(a)与LDL-C、apoB呈显著正相关(r=0.201、r=0.236,P0.01),与HDL-C、apoA-Ⅰ无相关性。apoB/apoA-Ⅰ是诊断冠心病最显著的独立危险因素(OR=31.577,95% CI:8.324～11 9.788,P=0.000),其次为脂蛋白(a)(OR=19.446,95% CI:3.831～98.716,P=0.000)。结论脂蛋白(a)与LDL-C、apoB呈正相关,提示三者均为动脉粥样硬化的危险因素;apoB/apoA-Ⅰ和脂蛋白(a)为冠心病的独立危险因素。     

The contribution of a moderate intake of alcohol to the presence of hypertension

The relationship between blood pressure and alcohol intake was examined in 2434 male and 1608 female London civil servants. These subjects had been selected from 24,000 office workers on the basis of responses to a health questionnaire. The men had an average blood pressure of 134/80 mmHg and consumed a mean of 62 g alcohol/week as beer, 28 g/week as wine or fortified wine and 18 g/week as spirits (a total of 11.8 drinks/week). The women had an average blood pressure of 133/79 mmHg and consumed 7 g alcohol/week as beer, 25 g/week as wine and 11 g/week as spirits (a total of 4.4 drinks/week). Twenty-five per cent of men and 24% of women had a casual diastolic pressure equal to or greater than 90 mmHg and were considered to have diastolic hypertension on the one occasion. There was no increase in either systolic or diastolic pressure in men until total alcohol intake exceeded 50 drinks/week. However, 1% of all men had hypertension associated with drinking alcohol and in those with hypertension, alcohol may have been the cause in between 4 and 9%. Defining 'hypertension' as a diastolic blood pressure of 90 mmHg or above on one occasion, 12-14% of people drinking more than 50 drinks of alcohol per week had hypertension associated with this intake of alcohol, and similarly, of those with both 'hypertension' and this level of intake, 36% could attribute their high blood pressure to their alcohol consumption.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of the effects of triphasic oral contraceptives with desogestrel or levonorgestrel on apolipoprotein A-I-containing high-density lipoprotein particles.

Recent observations suggest that the risk of coronary artery disease (CAD) is associated with both the level and composition of the two major populations of apolipoprotein (apo)-defined high-density lipoprotein (HDL) particles: those containing both apo A-I and apo A-II [Lp(AI,AII)] and those containing apo A-I without apo A-II [Lp(AI)]. While sex hormones are known to affect HDL, their influence on these apo-defined HDL particles is not known. We have determined the effects of two triphasic oral contraceptive (OC) formulations on these HDL particles in healthy normolipidemic women aged 21 to 35 years. The formulations contain comparable quantities of ethinyl estradiol (EE) and either desogestrel (DG), a minimally androgenic progestin, or levonorgestrel (LN), a more androgenic progestin. Lipid and lipoprotein levels were measured during the third week of the normal menstrual cycle and the sixth month of OC use. The DG/EE formulation significantly increased total cholesterol (C) 15%, triglyceride (TG) 99%, phospholipid (PL) 17%, apo A-I 28%, apo A-II 34%, apo B 21%, very-low-density lipoprotein cholesterol (VLDL-C) 238%, HDL-C 20%, and HDL3-C 28% (P < .02 to .005, n = 11), but not low-density lipoprotein cholesterol (LDL-C). The LN/EE formulation also increased total C 15%, TG 33%, apo A-I 15%, HDL3-C 21% (P < .05, n = 10), apo B 30% (P < .005), and, additionally, LDL-C 19% (P < .05). Both formulations increased Lp(AI,AII) (DG/EE, 34%, P < .005; LN/EE, 24%, P < .01). These changes reflected comparable increases of small (7.0 to 8.2 nm) and medium (8.2 to 9.2 nm) particles in the LN/EE group and a predominant increase of medium-sized particles in the DG/EE group. Also, in the LN/EE group but not the DG/EE group, there were fewer large (9.2 to 11.2 nm) particles. Lp(AI) increased only in the DG/EE group (25%, P = .075) and was due to the presence of more large particles. The level of Lp(AI) did not change in the LN/EE group, but the lipid/A-I ratio of these particles was lower (P = .012) and there were more small particles. Thus, triphasic OC formulations with progestins of different androgenicity had different effects on VLDL, LDL, and the level and composition of HDL particles with and without apo A-II, possibly reflecting estrogen/progestin/androgen balance. Estrogen dominance increases both Lp(AI,AII) and Lp(AI) and favors large Lp(AI) particles, while progestin/androgen dominance increases only Lp(AI,AII) and favors small particles. Because of the importance of HDL in the arterial wall physiology, OC formulations with different estrogen and progestin content may affect arterial wall health to a different extent.     

The NHLBI Twin Study: heritability of apolipoprotein A-I, B, and low density lipoprotein subclasses and concordance for lipoprotein(a).

Heritability of plasma apolipoprotein (apo) A-I, apo B, and low density lipoprotein (LDL) subclasses and concordance for lipoprotein(a) excess were assessed in 109 monozygotic (MZ) and 113 dizygotic (DZ) twin pairs participating in the third examination of the National Heart, Lung, and Blood Institute Twin Study. The intraclass correlation coefficient for apo A-I was significantly greater in MZ twins (0.56) than in DZ twins (0.37, P less than 0.05); however, apo A-I showed an unequal distribution in the two groups, with significantly greater total variance in DZ twins. Therefore the among-component estimate of genetic variance was applied, and the results indicated no significant heritability for apo A-I (P = 0.59). MZ and DZ twins had equal apo B variance. The intraclass correlation coefficient for apo B in MZ twins (0.71) was significantly higher than in DZ twins (0.25) (P less than 0.0001), indicating significant heritability for apo B. Plasma apo A-I levels were significantly correlated with alcohol intake (P less than 0.0001), body mass index (BMI, P less than 0.0001), and physical activity, while apo B levels were significantly correlated only with BMI (P less than 0.05). After plasma apo A-I and apo B concentrations were adjusted for all of these variables and for cigarette smoking, the analysis of variance and intraclass correlation coefficients remained virtually unchanged. The LDL type intraclass correlation coefficient was higher in MZ twins (0.58) than in DZ twins (0.32, P less than 0.005); however, greater total variance for this parameter in DZ twins was observed and after applying the among component estimate of genetic variance, no significant heritability of LDL type was observed. After adjustment for covariate effects the conclusions were not changed. Only 8.4% of MZ twin pairs, as compared with 26.7% of DZ twin pairs, were discordant for elevated lipoprotein(a) on gradient gels (P less than 0.0001). Our data indicate that there is a strong heritability for plasma apo B and lipoprotein(a), with only weak evidence for heritability of LDL type or plasma apo A-I levels within this population sample.     

The effect of atorvastatin on serum lipoproteins in acromegaly

OBJECTIVE: Acromegaly is associated with long-term adverse effects on cardiovascular mortality and morbidity. Reducing growth hormone secretion improves well-being and symptoms, but may not significantly improve the lipoprotein profile. An additional approach to cardiovascular risk reduction in acromegaly may therefore be to target lipoprotein metabolism directly. In this study we investigated the effect of statin treatment. DESIGN: Double blind, placebo-controlled, crossover study of the effects on circulating lipoproteins of atorvastatin 10 mg daily vs. placebo. Each treatment was given for 3 months in random order. SUBJECTS: Eleven patients with acromegaly. MEASUREMENTS: Lipids, lipoproteins, apolipoproteins, enzyme activity and calculated cardiovascular risk. RESULTS: Atorvastatin treatment compared to placebo resulted in a significant decrease in serum cholesterol (5.85 +/- 1.04 mmol/l vs. 4.22 +/- 0.69 mmol/l; mean +/- SD; P < 0.001), low-density lipoprotein (LDL) cholesterol (2.95 +/- 1.07 mmol/l vs. 1.82 +/- 0.92 mmol/l; P < 0.001), very low-density lipoprotein (VLDL) cholesterol (0.31 (0.21-0.47) mmol vs. 0.23 (0.13-0.30) mmol/l median (interquartile range); P < 0.05), apolipoprotein B (111 +/- 28 mg/dl vs. 80 +/- 18 mg/dl; P < 0.001), and calculated coronary heart disease risk (6.8 (3.3-17.9) vs. 2.8 (1.5-5.7)% over next 10 years; P < 0.01). Serum triglyceride was 1.34 (1.06-1.71) mmol/l on placebo and 1.14 (0.88-1.48) mmol/l on atorvastatin (ns). HDL cholesterol, apolipoprotein A1 and Lp(a) concentrations and cholesteryl ester transfer protein and lecithin: cholesterol acyl transferase activities were also not significantly altered. CONCLUSION: Atorvastatin treatment was safe, well tolerated and effective in improving the atherogenic lipoprotein profile in acromegaly.