北京地区中国人Apo（a）多态表型的分布及其与脂质及脂蛋…

为探讨Ａｐｏ（ａ）基因在中国人群中的分布特点及其与脂质及脂蛋白的关系，应用Ｗｅｓｔｅｒｎ印迹法检测１０２名北京地区中国汉族健康人群（男５７名，女４５名，年龄２１￣７４岁）的Ａｐｏ（ａ）多态表型，发现：（１）Ａｐｏ（ａ）表型的分布频率在不同性别之间无明显差异；低分子量表型（包括含有Ｂ、Ｓ１和Ｓ２的全部表型）占１５．７％，其中Ｓ２〉Ｓ２Ｓ３〉Ｂ和Ｓ２Ｓ４〉Ｓ１、ＢＳ４和Ｓ１Ｓ３；高分子量表型（包括只含     

脂蛋白（a）杂交瘤细胞株的建立及鉴定

用脂蛋白（ａ）［Ｌｎ（ａ）］免疫ＢＡＬＢ／ｃ小鼠，应用淋巴细胞杂交技术，将免疫小鼠的脾细胞与ＮＳ１骨髓瘤细胞进行融合，得到６Ｇ８、９Ｆ１１２株分泌抗Ｌｐ（ａ）单克隆抗体的杂交瘤细胞株，对２株细胞进行免疫学鉴定，应用间接ＥＬＩＳＡ法证明，培养上清效价１×１０－３～２×１０－３，培养上清与Ｌｐ（ａ）呈阳性反应，而与ａｐｏＡⅠ、ＡⅡ、Ｂ、ＣⅢ、Ｅ及血浆纤溶酶原（ＰＬＣ）均无交叉反应，ＥＬＩＳＡ相加实验证明：２株杂交瘤细胞株分别识别Ｌｐ（ａ）分子上２个不同的抗原决定簇。     

脂蛋白（a）的研究近况—分子生物学与疾病的相关性

脂蛋白（ａｑ）「Ｌｐ（ａ）」是一种与低密度脂蛋白类似的脂蛋白，由ＬＤＬ成分和载脂蛋白（ａ）「Ａｐｏ（ａ）」组成。ＬＰ（ａ）的血浆浓度与Ａｐｏ（ａ）分子量大小成反比，主要由Ａｐｏ（ａ）基因的多态性决定，有个体差异和种族差异。     

─株特异抗人血浆Lp（a）单克隆抗体（A5g3）的制备及特征分析

用序列超速离心和柱层析分离纯化的人血浆脂蛋白（ａ）（Ｌｐ（ａ））免疫Ｂａｌｂ／ｃ小鼠，得到具有对Ｌｐ（ａ）高抗体活性的小鼠脾细胞，与小鼠ＮＳ１骨髓瘤细胞经聚乙二醇（ＰＥＧ）杂文融合，建立分泌特异抗人血浆Ｌｐ（ａ）的单克隆杂交瘤细胞系，对其中的─株单克隆细胞株──Ａ５ｇ３进行了初步分析。Ａ５ｇ３分泌的单克隆抗体类型为ＩｇＧ（２ａ），经间接ＥＬＩＳＡ法分析与Ｌｐ（ａ）有高度反应性，与低密度脂蛋白（ＬＤＬ）及血浆纤溶酶原（Ｐｇ）无反应，免疫印迹结果也表明，Ａ５ｇ３可与纯化的或血浆中的Ｌｐ（ａ）结合，与血浆中的其它成分和纯化的ＬＤＬ及Ｐｇ均不结合，因此Ａ５ｇ３是特异抗人血浆Ｌｐ（ａ）的单克隆抗体。Ａ５ｇ３与还原后的Ｌｐ（ａ）也不结合，说明其与Ｌｐ（ａ）的结合依赖于抗原的完整结构，具有此种特性的Ｌｐ（ａ）特异抗体国内少见报道。     

二例心脑血管疾病患者载脂蛋白（a）表型的家系调查

调查１例高脂蛋白（ａ）［Ｌｐ（ａ）］心肌梗塞存活者和１例高Ｌｐ（ａ）脑卒中存活者载脂蛋白（ａ）［ａｐｏ（ａ）］表型的家系，分析了ａｐｏ（ａ）表型与其它血脂的关系。证明ａｐｏ（ａ）表型具有常染色体显性遗传特征，ａｐｏ（ａ）表型分子量与血清Ｌｐ（ａ）浓度有显著相关性（ｒ＝－０．７８４，Ｐ＜０．００１）。     

一株特异抗人血浆Lp（a）单克隆抗体（A5g3）的制备及特征分析

用序列超速离心和柱层析分离纯经的人血浆脂蛋白免疫Ｂａｌｂ／ｃ小鼠，得到具有对Ｌｐ（ａ）高抗体活性的小鼠脾细胞，与小鼠ＮＳ１骨髓瘤细胞经聚二乙二醇杂交蛤 ，建立分泌特异抗人血浆Ｌｐ（ａ）的单克隆杂交瘤细胞地其中一株单克隆细胞株－Ａ５ｇ３进行了初步分析。     

肾炎和肾病综合征患者血清脂蛋白（a）水平的临床意义

肾炎和肾病综合征患者血清脂蛋白（ａ）水平的临床意义程新宪１赵怡生２易忠群１赵惠芳１杨欣国３（１解放军３２３医院中心实验室，西安７１００５４２西安市中心医院３第四军医大学唐都医院心内科）近年研究证实脂蛋白（ａ）［Ｌｐ（ａ）］是动脉粥样硬化性心脑血管疾...     

脂蛋白(a)的研究近况——分子生物学与疾病的相关性

脂蛋白（ａ）［ＬＰ（ａ）］是一种与低密度脂蛋白（ＬＤＬ）类似的脂蛋白,由ＬＤＬ成分和载脂蛋白（ａ）［Ａｐｏ（ａ）］组成。ＬＰ（ａ）的血浆浓度与Ａｐｏ（ａ）分子量大小成反比,主要由Ａｐｏ（ａ）基因的多态性决定,有个体差异和种族差异。ＬＰ（ａ）有促动脉粥样硬化作用,ＬＰ（ａ）的高血浆浓度与冠心病、脑血管病、糖尿病等多种疾病有密切的相关性。     

氧化修饰引起脂蛋白（a）结构和生化特性变化

本文观察了体外丙二醛（ＭＤＡ），铜离子（Ｃｕ２＋氧化修饰的脂蛋白（ａ）［Ｌｐ（ａ）］结构和生物学性质的变化。氧化修饰Ｌｐ（ａ）过氧化程度增高，负电荷增加，易被巨噬细胞—清道夫受体识别和摄取。ＭＤＡ修饰Ｌｐ（ａ）出现新的ＭＤＡ－ＬＤＬ位点；同纤维蛋白溶酶原（Ｐｇ）竞争抑制试验显示氧化、修饰Ｌｐ（ａ）同Ｐｇ同源性增加。提示载脂蛋白（ａ）状态同动脉粥样硬化的病理过程有关。     

脂蛋白（a）在主动脉粥样硬化病变中的定位与定量研究

脂蛋白（ａ）［Ｌｉｐｏｐｒｏｔｅｉｎ（ａ），Ｌｐ（ａ）］是动脉粥样化中的独立危险因子，我们采用免疫组织化学技术、免疫电镜技术、酶联免疫吸附法及图像分析技术，研究了正常及不同程度动脉粥样硬化病变的尸检主动脉中Ｌｐ（ａ）分布的量及形式。结果显示：动脉粥样硬化血管壁Ｌｐ（ａ）含量显著增高，各不同病变区域Ｌｐ（ａ）有其独特的分布规律，Ｌｐ（ａ）主要位于细胞外基质中，只在少数泡沫细胞内才发现有Ｌｐ（ａ）。Ａ     

Effects of apoE gene polymorphism on Lp(a) concentrations depend on the size of apo(a): a study of 466 white men

 Polymorphisms in the genes for the low-density lipoprotein (LDL) receptor ligands, apolipoprotein E (apoE), and apolipoprotein B (apoB) are associated with variation in plasma levels of LDL cholesterol. Lp(a) lipoprotein(a) [Lp(a)] is LDL in which apoB is attached to a glycoprotein called apolipoprotein(a) [apo(a)]. Apo(a) has several genetically determined isoforms differing in molecular weight, which are inversely correlated with Lp(a) concentrations in blood. The interaction of apo(a) with triglyceride-rich lipoproteins differs with the size of apo(a), and therefore the effects of apoE gene polymorphism on Lp(a) levels could also depend on apo(a) size. We have investigated the possible effect of genetic variation in the apoE and apoB genes on plasma Lp(a) concentrations in 466 white men with different apo(a) phenotypes. Overall there was no significant association between the common apoE polymorphism and Lp(a), but in the subgroup with apo(a)-S4, concentrations of Lp(a) differed significantly among the apoE genotypes (P=0.05). Lp(a) was highest in the apoE genotypes ɛ₂ɛ₃ and ɛ₃ɛ₃ and lowest in genotype ɛ₃ɛ₄, and the apoE polymorphism was estimated to account for about 2.4% of the variation in Lp(a). In contrast, in the subgroup with apo(a)-S2 Lp(a) was significantly lower (P=0.04) in apoE genotype ɛ₂ɛ₃ than in genotype ɛ₃ɛ₃. Lp(a) concentrations did not differ among the XbaI (P=0.65) or SP 24/27 (P=0.26) polymorphisms of the apoB gene. The expected effects of both apoE and apoB polymorphism on LDL levels were significant in the whole population sample and in subjects with large-sized apo(a) isoforms (P<0.01), whereas no effect was seen in those with low molecular weight apo(a) isoforms. We conclude that the influence of apoE genotypes on Lp(a) concentrations depends on the size of the apo(a) molecule in Lp(a), possibly because both apo(a)-S4 and apoE4 have high affinity for triglyceride-rich lipoproteins and may be taken up and degraded rapidly by remnant receptors. Received: 12 January 1995 / Accepted: 12 July 1996     

Apolipoprotein(a) phenotypes and lipoprotein(a) concentrations in patients with hyperthyroidism

Lipoprotein(a) [Lp(a)] is a low-density lipoprotein (LDL) particle in which apolipoprotein B-100 (apoB) is attached to a glycoprotein 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. High plasma levels of Lp(a) are associated with atherosclerotic diseases. It is therefore of interest to study whether factors other than the apo(a) gene locus are involved in the regulation of Lp(a) concentrations. We measured plasma concentrations of Lp(a) and other lipoproteins and determined apo(a) phenotypes in 31 patients with hyperthyroidism, before and after the patients had become euthyroid by treatment. The mean concentration of LDL cholesterol rose from 2.67 to 3.88 mmol/l (P<0.01), apoB rose from 0.79 to 1.03 g/l (P<0.01), and the median Lp(a) concentration increased from 9.74 to 18.97 mg/dl (P<0.01) on treatment. Lp(a) concentrations were inversely associated to the size of the apo(a) molecule both before (P< 0.01) and after treatment (P<0.01). The increase in Lp(a) was significant patients with high molecular weight apo(a) phenotypes (n = 9; P<0.01) and in patients with low molecular weight apo(a) phenotypes (n=16; P< 0.01), but not in those with apo(a) null types (n = 6; P = 0.5). The low levels LDL cholesterol and apoB in untreated hyperthyroidism may result from increased LDL receptor activity. The increase in Lp(a) levels were not correlated with the increase in LDL cholesterol or apoB. Most other clinical evidence indicates that the LDL receptor is not important in Lp(a) catabolism, and we suggest that the low Lp(a) levels seen in thyroid hormone excess are caused by an inhibition of Lp(a) synthesis.Abbreviations Lp(a) lipoprotein(a) - apo(a) apolipoprotein(a) - apoB apolipoprotein B-100 - LDL low-density lipoprotein - HDL high-density lipoprotein - TG triglycerides - T ₄ thyroxine - T ₃ triiodothyronine - TSH thyrotropin     

Biogenesis of Lp(a) in transgenic mouse hepatocytes

Lipoprotein(a) [Lp(a)] biogenesis was examined in primary cultures of hepatocytes isolated from mice transgenic for both human apolipoprotein(a) [apo(a)] and human apoB. Steady-state and pulse-chase labeling experiments demonstrated that newly synthesized human apo(a) had a prolonged residence time (˜60 min) in the endoplasmic reticulum (ER) before maturation and secretion. Apo(a) was inefficiently secreted by the hepatocytes and a large portion of the protein was retained and degraded intracellularly. Apo(a) exhibited a prolonged and complex folding pathway in the ER, which included incorporation of apo(a) into high molecular weight, disulfide-linked aggregates. These folding characteristics could account for long ER residence time and inefficient secretion of apo(a). Mature apo(a) bound via its kringle domains to the hepatocyte cell surface before appearing in the culture medium. Apo(a) could be released from the cell surface by apoB-containing lipoproteins. These studies are consistent with a model in which the efficiency of posttranslational processing of apo(a) strongly influences human plasma Lp(a) levels, and suggest that cell surface assembly may be one pathway of human Lpfa) production in vivo. Transgenic mouse hepatocytes thus provide a valuable model system with which to study factors regulating human Lp(a) biogenesis.     

Apo E 2 phenotypes in type II diabetics with and without insulin therapy

Summary In 106 type II diabetics with persisting hyperlipidemia (i.e persistently increased triglycerides >200 mg/dl during intensive diabetes therapy) the Apo E polymorphism was examined in relation to IDDM (n=68) and NIDDM (n=38). It was shown that Apo E2 phenotypes are more (22.6% vs. 14.5%,p<0.05) and Apo E3 phenotypes less frequent in type II diabetics than in non-diabetic controls (86.8% vs. 94.7%,p<0.001). Looking at the increase in Apo E2 phenotypes it could be proved that the phenotype composition was distinctly different between diabetics with and in those without insulin therapy. While in NIDDM the increase was consequent to a higher concentration of Apo E2 homozygotes (p<0.005) it was caused by Apo E2 heterozygotes in IDDM (p<0.025) accompanied by a simultaneous decrease in Apo E3 homozygotes (p<0.025). Regarding blood lipids there was an increase in total cholesterol due only to VLDL cholesterol in IDDM as well as in NIDDM. It is concluded that in spite of similar hyperlipidemias in type II diabetics the increase in Apo E2 phenotypes is different; it is induced by heterozygotes in IDDM and by homozygotes in NIDDM.Abbreviations PVD peripheral vascular disease - CHD coronary heart disease - IDDM insulin dependent diabetes mellitus - NIDDM non insulin dependent diabetes mellitus - VLDL very low density lipoproteins - LDL low density lipoproteins - HDL high density lipoproteins     

Lipoprotein (a), low-density,intermediate-density lipoprotein,and blood pressure in a young male population

Summary Both hypercholesterolemia and hypertension are risk factors for atherosclerotic vascular disease, and elevated cholesterol levels occur more frequently than expected in patients with hypertension. Elevated levels of intermediate-density lipoproteins (IDL) and low-density lipoproteins (LDL) were shown to be atherogenic, and LDL, comprising the major cholesterol-carrying fraction in human plasma, are structurally related to lipoprotein (a) [Lp(a)], a further risk factor for atherosclerosis. In the present study we investigated 200 male employees (mean age 26±7 years) to determine whether the relationship of IDL and Lp(a) to systemic blood pressure is similar to the reported correlations between total and LDL cholesterol and systemic blood pressure. To this end blood pressure was measured several times in each individual, and lipids, lipoprotein-cholesterol, apolipoprotein B (apo B), and Lp(a) were determined in fasting serum. IDL cholesterol and apo B, the main protein component of IDL and LDL correlated with blood pressure. However, levels of Lp(a) correlated neither with systolic or diastolic blood pressure nor with lipoprotein cholesterol, body weight, or age. Although IDL and Lp(a) are considered lipoprotein risk factors for atherosclerosis, levels of Lp(a), unlike IDL, are not related to blood pressure, body weight, or age. Our data suggest different metabolic and pathophysiological mechanisms of the risk factors, IDL, LDL, and Lp(a).Abbreviations VLDL very low density lipoprotein - IDL intermediate-density lipoprotein - LDL low-density lipoprotein - ApoB Apolipoprotein B - Lp(a) lipoprotein (a) - BMI body mass index Dedicated to Prof. Dr. N. Zöllner on the occasion of his 70th birthday     

Lack of association of apolipoprotein E polymorphism with plasma Lp(a) levels in the Chinese

Apolipoprotein E (apoE) polymorphism and its influence on plasma lipids, lipoproteins, lipoprotein (a) [Lp(a)] and apolipoproteins was studied in 536 (270 males and 266 females) healthy Chinese in Singapore. From analysis of variance with age and BMI as covariates, apoE genotype was found to exert a significant influence on plasma total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and apoB in females. Its effect in males was marginally significant only on LDL-C. In both sexes, plasma TC, LDL-C and apoB were lower in those who were E2-3 than in those who were E3-3. There was no significant difference in log-transformed Lp(a) level between the apoE genotypes after adjusting for the confounding effect of LDL-C in addition to age and BMI. The percentage variance (R2times100) of the lipid traits explained by apoE polymorphism in the females was 4.94% for plasma TC, 5.85% for LDL-C and 4.25% for apoB. We conclude that: 1) ε2 allele had a lowering effect on plasma TC, LDL-C and apoB; 2) apoE polymorphism did not have any significant influence on Lp(a) concentration; and 3) the effect of apoE polymorphism on plasma TC, LDL-C and apoB was gender-specific, with a stronger influence in females than in males.     

LDL-unbound apolipoprotein(a) and carotid atherosclerosis in hemodialysis patients

High lipoprotein{a) [Lp(a)] plasma concentrations, which are genetically determined by apo(a) size polymorphism, are directly associated with an increased risk for atherosclerosis. Patients with end-stage renal disease (ESRD), who show an enormous prevalence of cardiovascular disease, have elevated plasma concentrations of Lp(a). In recent studies we were able to show that apo(a) size polymorphism is a better predictor for carotid atherosclerosis and coronary artery disease in hemodialysis patients than concentrations of Lp(a) and other lipoproteins. Less than 5% of apo(a) in plasma exists in a low-density lipoprotein (LDL)-unbound form. This “free” apo(a) consists mainly of disintegrated apo(a) molecules of different molecular weight, ranging from about 125 to 360 kDa. LDL-unbound apo(a) molecules are elevated in patients with ESRD. The aim of this study was therefore to investigate whether the LDL-unbound form of apo(a) contributes to the prediction of carotid atherosclerosis in a group of 153 hemodialysis patients. The absolute amount of LDL-unbound apo(a) showed a trend to increasing values with the degree of carotid atherosclerosis, but the correlation of Lp(a) plasma concentrations with atherosclerosis was more pronounced. In multivariate analysis the two variables were related to neither the presence nor the degree of atherosclerosis. Instead, the apo(a) phenotype took the place of Lp(a) and LDL-unbound apo(a). After adjustment for other variables, the odds ratio for carotid atherosclerosis in patients with a low molecular weight apo(a) phenotype was about 5 (p < 0.01). This indicates a strong association between the apo(a) phenotype and the prevalence of carotid atherosclerosis. Finally, multivariate regression analysis revealed age, angina pectoris and the apo(a) phenotype as the only significant predictors of the degree of atherosclerosis in these patients. In summary, it seems that LDL-unbound apo(a) levels do not contribute to the prediction of carotid atherosclerosis in hemodialysis patients. However, this does not mean that “free”, mainly disintegrated, apo(a) has no atherogenic potential.     

Study of lipoprotein (a) phenotypes in Ivorian subject

The objective of this study was to identify the apo (a) phenotypes and to find a correlation between apo (a) isoform size and Lp (a) plasma level in Ivorian subjects. This study involved 30 healthy subjects (11 females and 19 males) aged of 35 +/- 2 years. Lp (a) plasma levels have been determined by technical ELISA, while phenotypes of apo (a) have been identified by agarose high resolution electrophoresis followed by Western blot. The Lp (a) plasma level in our population was 329 +/- 291 mg/l and 30% of our population's Lp (a) plasma levels were above 300 mg/l. 70% of our subjects have homozygous phenotype and 30% have heterozygous phenotype. Three apo (a) isoforms (S2, S3, S4) have been identified in homozygous subjects whereas four apo (a) isoforms (B, S2, S3, S4) have been detected in heterozygous subjects. Their sizes varied from 13 to 33 kringle 4.77% of our subjects had apo (a) isoforms whose sizes were above 22 kringle 4. No correlation has been observed between the size of apo (a) isoforms and the Lp (a) plasma level in homozygous subjects. Our results highlight apo (a) polymorphism in Ivorians. Homozygous phenotypes and large size apo (a) isoforms predominate in this population.     

Association of apoE gene polymorphisms with lipid metabolism in renal diseases

Background and ObjectivesApolipoprotein E (apoE) plays a central role in the metabolism and homeostasis of lipids. ApoE gene encodes three major isoforms: ε2, ε3 a nd ε4 forming six phenotypes: E2E2, E2E3, E2E4, E3E3, E3E3 and E4E4. Disorders of the lipid metabolism and the homeostasis are frequently coexist in renal diseases. The association between gene polymorphisms of apoE and lipid metabolism were not consistent. This meta-analysis was performed to assess the association between gene polymorphisms of apoE and lipid metabolism in renal diseases.MethodsA pre-defined literatures search and selection of eligible relevant investigations were performed to extract and collect data from electronic databases.ResultsSixteen articles were enrolled for the analysis of association between apoE gene polymorphisms and lipid metabolism. Subjects with E3E4 had a higher total cholesterol (TC) than those with E3E3, and subjects with E2E3 had a lower TC than those with E3E3. Subjects with ε2, had a lower TC than those with ε3 or ε4, and subjects with ε4 had a higher TC than those with, ε3. Subjects with E2E2, E2E3 or E4E4 had a higher triglyceride (TG) than those with E3E3. Subjects with ε4 had a higher TG than those with ε3. Subjects with ε2, had a higher level of TG than those with non-ε2. Subjects with E3E4 had a slightly lower high-density lipoprotein (HDL) than those with E3E3. E3E4 appeared to be associated with lower levels of HDL. Subjects with E2E2, E2E3 had a notably lower low-density lipoprotein (LDL) than those with E3E3. Subjects with ε2, had a lower LDL than those with ε3 or ε4 ApoE gene polymorphisms were not associated with very low-density lipoprotein, and lipoprotein (a) [Lp(a)]. Subjects with E2E3 or E2E4 had higher apoE levels than those with E3E3, and subjects with E4E4 had lower apoE levels than those with E3E3.ConclusionApoE gene polymorphisms are associated with the expression of TC, TG HDL, LDL, Lp(a) or apoE.     

Apo E polymorphism among Egyptian patients with essential hypertension

Hypertension (HTN) is a chronic condition of concern due to its role in the causation of coronary artery disease (CAD), stroke, and other vascular complications. Essential hypertension (EH) is a multifactorial disorder arising from the influence of several susceptibility genes and environmental stimuli. Apolipoprotein E (Apo E) plays an essential role in clearance of chylomicron remnants and very low-density lipoproteins (VLDL). Apo E gene has three alleles (E2, E3, and E4) that give rise to six different genotypes. A significant association of E4 allele has been observed with HTN in addition to the other well-known risk factors and positive family history. Carriers of E4 allele form a higher risk group showing greater susceptibility to CAD. These observations emphasize the need of genotyping Apo E in patients with EH as an important molecular tool in personalized medicine. The aim of this work was to study the association between Apo E gene polymorphism and EH in Egyptian patients as well as correlating different Apo E genotypes with serum lipids. The study was conducted on 50 patients with EH and 50 age-matched controls. DNA analysis was performed using polymerase chain reaction restriction fragment length polymorphism. The E3/E3 genotype was found in 85.42 % of patients, compared to 80 % in controls. E3/E4 (8.33 %) and E2/E3 (6.25 %) were lower in patients compared to controls 12 and 8 %, respectively. E4/E4 and E2/E2 genotypes were only found in two patients (4 %). Total cholesterol and low-density lipoprotein were significantly higher in E3/E4 as compared to E3/E3 and E2/E3. However, there was no significant difference in triglyceride, high-density lipoprotein, and VLDL.