载脂蛋白（a）基因结构与功能研究

脂蛋白（ａ）［Ｌｐ（ａ）］是一种低密度脂蛋白（ＬＤＬ）样的脂蛋白。ＬＤＬ样脂蛋白是致动脉粥样硬化的主要危险因素。ＬＤＬ样脂蛋白与Ｌｐ（ａ）不同之处就在于前者比后者多个载脂蛋白（ａ）［ａｐｏ（ａ）］。ａｐｏ（ａ）基因结构与血纤维蛋白溶酶原同源。ａｐｏ（ａ）与血纤维蛋白溶酶原活性竞争可以说明一些与Ｌｐ（ａ）有关的病理生理学问题。现已识别６个高度相关的基因，至少在重叠的基因组克隆附近发现４个相关基因。目     

离体培养动脉内皮细胞结合,内移和降解脂蛋白（a）作用的研究

本文研究离体培养动脉内皮细胞通过ＬＤＬ受体结合，内移和降解脂蛋白（ａ）［Ｌｉｐｏｐｒｏ－ｔｅｉｎ（ａ），Ｌｐ（ａ）］的作用，实验取第３－４代离体培养的动脉内皮细胞分为两组，对照组培养液中不加碘标的脂蛋白（ａ）［＾１２５Ｉ－Ｌｐ（ａ）］，实验组培养液中加＾１２５Ｉ－Ｌｐ（ａ）最终浓度分别为０．２５、０．５、１、１０和５０μｇ／ｍｌ。用γ计数器测定内皮细胞对Ｌｐ（ａ）的结合、内移和降解值，并测定内皮细     

老年脑血管病患者脂蛋白（α）检测及其临床意义

用放免的方法测定了５０例脑血管病（ＣＶＤ）患者血清脂蛋白（α）［Ｌｐ（α）］浓度，对比分析了患者Ｌｐ（α）、甘油三脂（ＴＧ）、总胆固醇（ＴＣ）、高密度脂蛋白胆固醇（ＨＤＬ－Ｃ）、低密度脂蛋白胆固醇（ＬＤＬ－Ｃ）、脱脂蛋白Ａ－Ｉ（ａｐｏＡ－Ｉ）、ａｐｏＢ１００的浓度及变化，分析了Ｌｐ（α）浓度及ＴＧ、ＴＣ和胶脂蛋白的相关性。结果：ＣＶＤ患者血清Ｌｐ（α）浓度（０．２２４±０．０４ｇ／Ｌ），显著高于对     

血清Lp（a）水平与Mn－SOD活力相关性研究

血清Ｌｐ（ａ）水平与Ｍｎ－ＳＯＤ活力相关性研究戚大梁，庄一义脂蛋白（ａ）［Ｌｐ（ａ）］首先由Ｂｅｒｇ于１９６３年报道以来［１］，众多学者对Ｌｐ（ａ）的结构、合成、代谢、遗传、人群分布及与心脑血管疾病的关系进行了深入研究。超氧化物歧化酶（ＳＯＤ）是以超...     

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。     

人主动脉粥样硬化病变中修饰脂蛋白的研究

目的研究人粥样硬化病变主动脉中丙二醛（ＭＤＡ）和４羟基壬烯醛（ＨＮＥ）修饰载脂蛋白Ｂ（ａｐｏＢ）的分布特点、含量和理化特性,并与脂蛋白（ａ）［Ｌｐ（ａ）］和ａｐｏＢ的分布进行比较。方法应用免疫组织化学、电镜、免疫电镜以及生物化学等方法进行定性或定量分析。结果ＭＤＡ和ＨＮＥ－ａｐｏＢ在细胞外基质中的分布与Ｌｐ（ａ）和ａｐｏＢ一致,但在泡沫细胞内则有不同。ＭＤＡ－ａｐｏＢ和ＨＮＥ－ａｐｏＢ在泡沫细胞内呈环状、孔状分布,与蜡样色素相似。病变动脉内膜低密度脂蛋白的超微结构、化学成分及电泳行为均与体外修饰脂蛋白相似,其醛类修饰ａｐｏＢ含量明显高于无病变者。结论脂蛋白的氧化性修饰是动脉粥样硬化发生的必要条件。     

藏族人载脂蛋白B基因信号肽多态性与血脂水平

目的：了解正常藏族人群载脂蛋白Ｂ（ａｐｏＢ） 基因多态性及其血脂特点。方法：随机选取１００ 例正常成年藏族受试者,男女各半,年龄１８ ～６０ 岁。测定其血清甘油三脂（ＴＧ） 、总胆固醇（ＴＣ） 、低密度脂蛋白胆固醇（ＬＤＬ－ Ｃ） 、高密度脂蛋白胆固醇（ ＨＤＬ－ Ｃ） 、ａｐｏＡＩ、ａｐｏＢ 和脂蛋白（ａ）［Ｌｐ（ａ）］ 的浓度;并采用ＰＣＲ 方法检测其ａｐｏＢ 基因信号肽插入／缺失（ｉｎｓ／ｄｅｌ） ＤＮＡ 片段的多态性,计算各等位基因的分布频率。结果：藏族人群中以ｉｎｓ 等位基因分布为主（０－７４５） ,ｄｅｌ等位基因频率占０－２５５ ,两种等位基因分布无明显的性别差异。组成的三种基因型分别为ｉｎｓ／ｉｎｓ ５６ 例、ｉｎｓ／ｄｅｌ ３７ 例、ｄｅｌ／ｄｅｌ ７ 例。与汉族人群比较,藏族ｉｎｓ／ｄｅｌ 等位基因的频率与其相近,但ｄｅｌ 等位基因频率显著低于西方高加索人种（０－３４０ ,Ｐ＜ ０－０５） 。藏族人群中男女各年龄段（１８ ～３９ 岁、４０ ～６０ 岁） 的各项血脂指标变化不大,但ＴＣ、ＬＤＬ－ Ｃ 和ａｐｏＢ的含量显著低于汉族和西方人群,Ｌｐ（ａ） 的水平与后者接近。ｄｅｌ 等位基因的个体其ＬＤＬ－ Ｃ 的浓度高于ｉｎｓ 者,特别是     

钙离子与牛磺酸两者跨心肌细胞膜内流的相互影响

目的和方法：取新生ＳＤ大鼠心室肌制备培养搏动心肌细胞，采用放射性同位素４５Ｃａ２＋及３Ｈ－牛磺酸示踪技术，观察钙离子与牛磺酸跨心肌细胞膜内流的相互影响。结果：（１）牛磺酸内流在低胞外Ｃａ２＋浓度（［Ｃａ２＋］ｏ，０．５ｍｍｏｌ／Ｌ）和高［Ｃａ２＋］ｏ（４０ｍｍｏｌ／Ｌ）均比正常［Ｃａ２＋］ｏ（１５ｍｍｏｌ／Ｌ）和高［Ｃａ２＋］ｏ（４０ｍｍｏｌ／Ｌ）时增加，尤以低［Ｃａ２＋］。时明显；异搏定（１０μｍｏｌ／Ｌ）能促进牛磺酸的内流；（２）１０～２０ｍｍｏｌ／Ｌ牛磺酸对不同［Ｃａ２＋］。（０５、１５和４０ｍｍｏｌ／Ｌ）下的Ｃａ２＋内流均有抑制作用，而１ｍｍｏｌ／Ｌ牛磺酸只抑制高［Ｃａ２＋］ｏ时Ｃａ２＋内流，对低［Ｃａ２＋］ｏ和正常［Ｃａ２＋］ｏ时Ｃａ２＋内流无明显作用；１～２０ｍｍｏｌ／Ｌβ－丙氨酸对Ｃａ２＋内流无明显影响。结论：胞外Ｃａ２＋浓度的变化可直接影响牛磺酸内流，而牛磺酸能抑制Ｃａ２＋的内流，两者相互影响，从而发挥牛碘酸调节细胞内Ｃａ２＋浓度的作用     

载脂蛋白（a）的遗传学研究进展

脂蛋白（ａ）（Ｌｐ（ａ））是动脉粥样硬化的独立危险因子，它由载脂蛋白（ａ）（ａｐｏ（ａ））与ＬＤＬ中的ａｐｏＢ１００以二硫键连接而成。ａｐｏ（ａ）的结构与血浆纤溶酶原高度同源，其基因定位于６ｑ２６－２７，亦与纤溶酶原基因紧邻。ａｐｏ（ａ）受单一位点的至少１９个等位基因所控制，呈常染色体共显性遗传。它存在表型多态性，包括密度多态性和大小多态性，至少有１１种不同大小的ａｐｏ（ａ）蛋白。多态性的根本原因     

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...     

Phenotype of apolipoprotein E influences the lipid metabolic response of postmenopausal women to hormone replacement therapy

Objectives: We investigated whether the phenotype of apolipoprotein E (apo E) would influence the response of postmenopausal Japanese women to hormone replacement therapy (HRT). Methods: We measured the plasma levels of lipoprotein and apolipoprotein in 242 postmenopausal women at baseline and again after 12 months of HRT. Patients were divided into three groups according to apo E phenotype: E2+ (E2/2 and E2/3, n=21), E3/3 (n=176), E4+ (E3/4 and E4/4, n=45). Results: We found that the E4+ group had the highest levels of total and low density lipoprotein (LDL) cholesterol and apolipoprotein B, being significantly higher than in the E2+ group at baseline. The plasma levels of total and LDL cholesterol showed a significant decrease only in the E2+ and E3/3 groups after 12 months of HRT (E2+ group, total cholesterol −8.9% and LDL cholesterol −21.5%; E3/3 group, total cholesterol −2.9% and LDL cholesterol −9.5%). No significant difference in the reduction of total and LDL cholesterol was found in the E4+ group. Other lipid parameters did not differ in the three groups. Conclusions: These data show that the apo E phenotype influenced the response of lipid metabolism in postmenopausal women to HRT, especially in the reduction of LDL cholesterol. Therefore, apo E phenotyping may be important in predicting the cholesterol-lowering effect of HRT.     

Clinical implications of the apolipoprotein E polymorphism and genetic variants: current methods for apo E phenotyping

There is agreement about the influence of the genetic apolipoprotein (apo E) polymorphism on plasma lipid and apoprotein levels in man. Whereas the association of the apo E2 isoform with primary dysbetalipoproteinemia and hyperlipoproteinemia type III is well established, the plasma- and LDL-cholesterol lowering effects of apo E2 and the phenomenon of apo E4 raising these parameters on the development of coronary heart disease is still a matter of controversial discussion. Despite these uncertainties the knowledge of an individual's apo E phenotype may provide additional information in future to judge its risk to develop atherosclerosis. From a variety of methods meanwhile described to analyze the polymorphism and evaluate the apo E phenotype the author has modified three procedures to apply to different questions concerning apo E isoform analysis. They concern the visualization of the apo E pattern in diluted solutions and those containing high salt concentrations, the apo E phenotyping on a large scale basis from whole plasma avoiding a possible misinterpretation by a thrombin fragment of apo E and finally the search for new apo E variants with a high resolution system on immobilized pH gradient gels.     

Candidate genes involved in cardiovascular risk factors by a family-based association study on the island of Kosrae,Federated States of Micronesia

Altered plasma levels of lipids and lipoproteins, obesity, hypertension, and diabetes are major risk factors for atherosclerotic cardiovascular disease. To identify genes that affect these traits and disorders, we looked for association between markers in candidate genes (apolipoprotein AII (apo AII), apolipoprotein AI-CIII-AIV gene cluster (apo AI-CIII-AIV), apolipoprotein E (apo E), cholesteryl ester transfer protein (CETP), cholesterol 7alpha-hydroxylase (CYP7a), hepatic lipase (HL), and microsomal triglyceride transfer protein (MTP)) and known risk factors (triglycerides (Tg), total cholesterol (TC), apolipoprotein AI (apo AI), apolipoprotein AII (apo AII), apolipoprotein B (apo B), body mass index (BMI), blood pressure (BP), leptin, and fasting blood sugar (FBS) levels.) A total of 1,102 individuals from the Pacific island of Kosrae were genotyped for the following markers: Apo AII/MspI, Apo CIII/SstI, Apo AI/XmnI, Apo E/HhaI, CETP/TaqIB, CYP7a/BsaI, HL/DraI, and MTP/HhpI. After testing for population stratification, family-based association analysis was carried out. Novel associations found were: 1) the apo AII/MspI with apo AI and BP levels, 2) the CYP7a/BsaI with apo AI and BMI levels. We also confirmed the following associations: 1) the apo AII/MspI with Tg level; 2) the apo CIII/SstI with Tg, TC, and apo B levels; 3) the Apo E/HhaI E2, E3, and E4 alleles with TC, apo AI, and apo B levels; and 4) the CETP/TaqIB with apo AI level. We further confirmed the connection between the apo AII gene and Tg level by a nonparametric linkage analysis. We therefore conclude that many of these candidate genes may play a significant role in susceptibility to heart disease.     

Molecular basis of type III hyperlipoproteinemia in Germany

Type III hyperlipoproteinemia (HLP) is usually associated with homozygosity for apolipoprotein (apo) E2 (Arg₁₁₂→ Cys, Arg₁₅₈→ Cys). This common apo E isoform is defective in its binding to lipoprotein receptors. However, other rare mutations in the apo ϵ gene may also, in part dominantly, predispose to the disease. In order to assess the prevalence of rare apo E variants and mutations in the apo ϵ gene in Germany, we examined apo ϵ genotypes by restriction isotyping (RI) and apo E phenotypes by isoelectric focusing (IEF) in 107 German patients with type III HLP. Concordance between apo ϵ genotype and apo E phenotype was observed in 101 subjects (94.4%). Six individuals (5.6%) had genotypes and phenotypes other than E2/2. One subject was apparently homozygous for apo E2 by IEF, but heterozygous for ϵ3/2 by RI. Sequencing of the apo ϵ gene disclosed a hitherto undescribed point mutation (TGG→ TGA) at the third position of the codon for amino acid 20 (Trp), introducing a premature termination codon. This is the first study demonstrating that in the German population type III HLP is mainly associated with homozygosity for apo E2 (Arg₁₁₂→ Cys, Arg₁₅₈ → Cys) and that discrepancies between apo ϵ genotype and apo E phenotype are rare in this genetic condition. Hum Mutat 11:417–423, 1998. © 1998 Wiley-Liss, Inc.     

Elevated complement activities of sera from patients with high density lipoprotein deficiency (Tangier disease): the presence of normal level of clusterin and the possible implication in the atherosclerosis.

Clusterin (apolipoprotein J, SP-40,40), as well as apolipoprotein A-I (apo A-I) and apolipoprotein A-II (apo A-II), are apolipoprotein components of high density lipoprotein (HDL), but not of low density lipoprotein. In spite of the deficiencies of apo A-I, apo A-II and HDL in the sera of patients with Tangier disease, clusterin was found in them at normal level. While clusterin was present as the component of HDL with apo A-I in sera of normal donors, it was present as a protein which did not form a complex in sera of Tangier patients. SC5b-9 made from the sera of Tangier patients contained normal amounts of clusterin and was deficient in apo A-I, indicating that clusterin could be incorporated into the SC5b-9 complex without apo A-I. The complement activities of the sera of the patients were higher than those of normal donors. These results may be explained by the deficiencies of apo A-I, apo A-II and HDL in the patients, because they were suggested to be the inhibitors of the reactive haemolysis of complement. The elevated complement activities of the patients might be related to the severe atherosclerotic lesions in Tangier disease.     

Single effects of apolipoprotein B, (a), and E polymorphisms and interaction between plasminogen activator inhibitor-1 and apolipoprotein(a) genotypes and the risk of coronary artery disease in Czech male caucasians

To evaluate whether polymorphisms in genes whose products are involved in lipid metabolism and fibrinolysis alter the risk of coronary artery disease (CAD), allele frequencies of four genetic polymorphisms were ascertained by PCR-based methods in 175 Czech male patients with coronary artery disease and in 222 Czech men with no symptoms of CAD. The following polymorphisms were studied: apolipoprotein B (apo B) signal peptide insertion/deletion polymorphism, 5' apolipoprotein(a) [apo(a)] TTTTA repeat polymorphism, apolipoprotein E (apo E) varepsilon2, varepsilon3, varepsilon4 polymorphism, and plasminogen activator inhibitor-1 (PAI-1) 4G/5G promoter polymorphism. Apo B and apo(a) allele frequencies differed significantly between the CAD and the control groups (P<0.01 each), with higher frequencies of apo B deletion and apo(a) shorter repeat alleles in the CAD group. We did not observe any differences in allele frequencies of either PAI-1 or apo E polymorphisms but the genotype frequencies of apo E were slightly different between the two groups (P<0.05). In addition, we observed a gene-gene interaction between the PAI-1 and apo(a) polymorphisms with respect to the risk of CAD. None of the polymorphisms studied were associated with the severity of CAD or a history of myocardial infarction. Our findings support the idea that several polymorphisms in apolipoprotein genes may by themselves and/or in interaction with other polymorphisms contribute to risk factors for CAD in men.     

Apolipoprotein B in cholesterol-containing drusen and basal deposits of human eyes with age-related maculopathy

Lipids accumulate in Bruch's membrane (BrM), a specialized vascular intima of the eye, and in extracellular lesions associated with aging and age-related maculopathy (ARM). We tested the hypothesis that ARM and atherosclerotic cardiovascular disease share molecules and mechanisms pertaining to extracellular lipid accumulation by localizing cholesterol and apolipoprotein B (apo B) in BrM, basal deposits, and drusen. Human donor eyes were preserved <4 hours postmortem and cryosectioned. Sections were stained with traditional lipid stains and filipin for esterified and unesterified cholesterol or probed with antibodies to apo B, apo E, and apo C-III. Normal adult retinal pigment epithelium (RPE) was subjected to RT-PCR and Western blot analysis for apolipoprotein mRNA and protein. Esterified and unesterified cholesterol was present in all drusen and basal deposits of ARM and normal eyes. Both apo B and apo E but not apo C-III were found in BrM, drusen, and basal deposits. Fewer macular drusen were stained by traditional lipid stains and apolipoprotein antibodies than peripheral drusen. RPE contained apo B and apo E mRNA and protein. Finding cholesterol and apo B in sub-RPE deposits links ARM with important molecules and mechanisms in atherosclerosis initiation and progression. The combination of apo B mRNA and protein in RPE raises the possibility that intraocular assembly of apo B-containing lipoproteins is a pathway involved in forming cholesterol-enriched lesions in ARM.     

Expression of biologically active rat apolipoprotein AIV in Escherichia coli

Rat apolipoprotein AIV (apo AIV) is a 43-kDa intestinal apolipoprotein that is important in lipid metabolism and the suppression of food intake. In this study, a full-length rat apo AIV was expressed in Escherichia coli and purified in a bioactive form. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and mass spectrometric analysis revealed that the isolated recombinant protein has a molecular mass of approximately 43 kDa, similar to that of natural rat apo AIV. Immunoblot analysis and N-terminal amino acid sequencing confirmed the identity of the recombinant apo AIV protein as natural rat apo AIV. The recombinant protein was functional in lipoprotein binding assays. Biological activity was assessed behaviorally in that the recombinant protein suppressed food intake of fasted rats comparably to natural rat apo AIV. Neither native nor recombinant apo AIV elicited a conditioned taste aversion (CTA) at doses that suppress feeding. These results indicate that the recombinant apo AIV is structurally and functionally indistinguishable from rat natural apo AIV, making this overexpression and purification scheme a powerful tool for future structure and function studies.     

Reciprocal effects of apolipoprotein E alleles (ε2 AND ε4) on plasma lipid levels in normolipidemic subjects

A significantly lower frequency of the epsilon 2 allele and a significantly higher frequency of the epsilon 3 allele were found in the normolipidemic Japanese population than those in the normolipidemic Caucasian populations. We have compared plasma lipid variables among the apolipoprotein (apo) E phenotype groups and estimated the average effects of the three common alleles (epsilon 2, epsilon 3 and epsilon 4) on plasma lipid levels in normolipidemic subjects. Plasma triglyceride (TG), very low density lipoprotein (VLDL)-TG, VLDL-cholesterol (C) and apo E levels were high in the apo E3/2 group, intermediate in the apo E3/3 group and low in the apo E4/3 group, whereas plasma total cholesterol (TC), low density lipoprotein (LDL)-C and high density lipoprotein (HDL)-C levels were low in the apo E3/2 group, intermediate in the apo E3/3 group and high in the apo E4/3 group. Furthermore, the epsilon 2 allele had an effect to increase the TG, VLDL-TG, VLDL-C and apo E levels and decrease the TC, LDL-C and HDL-C levels, whereas the epsilon 4 allele had an effect opposite to the epsilon 2 allele. These results indicate that the epsilon 2 and epsilon 4 alleles have the reciprocal effects on plasma lipid, lipoprotein and apo E levels.     

Plasma apolipoprotein H (beta 2-glycoprotein I) phenotype frequencies in a Japanese population

We determined plasma apolipoprotein H (beta 2-glycoprotein I) levels in 300 healthy adult individuals and evaluated the frequencies of the BgN and BgD alleles in a Japanese population. These results were then compared with the previous reports. The plasma apo H levels in the subjects showed bimodal distribution: 274 subjects were in the range 15.6-33.2 mg/dl and were considered to be homozygous for BgN (phenotype NN), and 26 subjects were found in the range 9.6-14.8 mg/dl and were presumably heterozygous for BgN and BgD (phenotype ND). In this study, no sample below 5 mg/dl (phenotype DD) was found. Mean plasma apo H levels in NN and ND groups were 22.1 +/- 1.6 mg/dl and 12.5 +/- 1.6 mg/dl, respectively. The gene frequencies of BgN and BgD in a Japanese population were 0.957 and 0.043, respectively. These results were similar to gene frequencies of BgN and BgD in Caucasoids.