Effects of insulin, dexamethasone and glucagon on the production of apolipoprotein A-I in cultured rat hepatocytes

Cultured rat hepatocytes were used to study the effects of hormones on the production of apo A-I. In addition, we compared these effects with the production of albumin. Hepatocytes were isolated from normal adult rat livers and cultured in MEM, as nearly confluent monolayers. In the absence of hormones, apo A-I and albumin accumulated in the culture medium almost linearly for periods up to 24 h. The rates of accumulation of apo A-1 and albumin in the medium were 22 ng/mg cell protein per h and 1.2 μg/mg cell protein per h, respectively. During the incubations the cellular contents of apo A-1 remained constant.

Insulin stimulated the production of albumin at concentrations over 10⁻¹⁰ M, but inhibited the production of apo A-I at concentrations over 10⁻⁸ M. Dexamethasone showed no significant effects on albumin production but stimulated apo A-1 production at concentrations over 10⁻⁶ M. Glucagon inhibited the production of albumin and apo A-I dose-dependently at concentrations over 10⁻¹⁰ M. Thus, the production of albumin and apo A-1 are presumably controlled by different regulatory mechanisms.     

国人载脂蛋白E基因多态性与冠心病发病之间的相关性

目的 探讨载脂蛋白E基因112bp与158bp位点多态性与血脂水平及冠心病发生之间的关系。方法采用生物化学法分别测量经冠状动脉造影证实的89例冠心病患者及43例正常人空腹血脂水平，应用聚合酶链反应限制片长多态性分析方法对载脂蛋白E基因DNA244bp的5’末端片段进行限制性片段长度多态性分析。结果冠心病组甘油三酯、总胆固醇、低密度脂蛋白、载脂蛋白B及脂蛋白（a）水平均高于对照组（P〈0．05），而载脂蛋白A1水平则低于对照组（P〈0、05）；冠心病组载脂蛋白Eε2基因型频率明显为低（P〈0．001）。结论载脂蛋白E基因多态性特征会明显影响人群中个体的血浆脂质水平，从而增加人群中个体发生冠心病的危险。     

载脂蛋白A-I模拟肽D-4F对巨噬细胞源性泡沫细胞清道夫受体A1的抑制作用

 目的:研究载脂蛋白A-I模拟肽D-4F对氧化低密度脂蛋白（oxidized low-density lipoprotein,ox-LDL）所诱导的巨噬细胞源性泡沫细胞清道夫受体A1（scavenger receptor A1,SR-A1）的抑制作用及其机制。方法:体外培养RAW264.7巨噬细胞,给予不同浓度的D-4F（12.5、25和50 mg/L）、紊乱模拟肽sD-4F（50 mmol/L）处理1 h或者5 mmol/L内质网应激（endoplasmic reticulum stress,ERS）抑制剂 4-苯丁酸处理30 min后,再加入ox-LDL （100 mg/L）继续培养12 h。另外培养巨噬细胞给予50 mg/L D-4F 或sD-4F 处理1 h,再加入2 mg/L ERS诱导剂衣霉素（tunicamycin,TM）处理4 h。MTT法检测细胞活力;试剂盒检测细胞内总胆固醇含量;分别采用免疫印迹法和实时荧光定量聚合酶链反应（real-time PCR）技术检测SR-A1和ERS标志分子葡萄糖调节蛋白78 （glucose-regulated protein 78,GRP78）蛋白和mRNA表达变化;采用多功能酶标仪检测DiI-ox-LDL摄取情况。结果:D-4F明显减轻ox-LDL所诱导的巨噬细胞损伤和细胞内的胆固醇蓄积。ox-LDL可显著上调SR-A1和GRP78表达,而D-4F对上述变化具有明显抑制作用,且呈浓度依赖性。D-4F显著抑制TM所诱导的SR-A1和GRP78蛋白水平以及巨噬细胞对ox-LDL的摄取。结论: D-4F可通过抑制SR-A1 表达减轻ox-LDL所诱导的巨噬细胞内胆固醇蓄积和细胞损伤,其机制可能与抑制GRP78介导的ERS信号途径有关。     

Apolipoprotein C3 Gene Polymorphisms Are Not a Risk Factor for Developing Non-Alcoholic Fatty Liver Disease: A Meta-Analysis

Context:

Our objective was to evaluate the effect of gene polymorphisms of apolipoprotein C3 (APOC3) on the development of non-alcoholic fatty liver disease (NAFLD) in different populations.

Evidence Acquisition:

We performed a meta-analysis of all relevant studies published in the literature. A total of 115 clinical trials or reports were identified, but only seven trials met our inclusion criteria. A meta-analysis was performed according to the Cochrane Reviewers’ Handbook recommendations.

Results:

Five hospital-based and two population-based case-control studies were included in the final analysis. The overall frequency of APOC3 gene polymorphisms was 67.5% (1177/1745) in NAFLD and 68.8% (988/1437) in controls. The summary odds ratio for the association of gene polymorphisms of APOC3 and the risk of NAFLD was 1.03 (95% CI: 0.89-1.22),which was not statistically significant (P > 0.05).

Conclusions:

Our meta-analysis, while not ruling out possible publication bias, showed no association between gene polymorphisms of APOC3 and the risk of NAFLD development in different populations in the world.     

ApoE and TDP-43 neuropathology in two siblings with familial FTLD-motor neuron disease

Frontotemporal lobar degeneration with motor neuron disease (FTLD-MND) is characterized by neuronal cytoplasmic inclusions containing TDP-43. Apolipoprotein E4 (apoE4), derived from the apoE ?4 allele, enhances brain atrophy in FTLD through unknown mechanisms. Here, we studied two siblings with C9ORF72-linked familial FTLD-MND, an apoE ?4 homozygote and an apoE ?3 homozygote. The apoE ?4 homozygote had more cognitive-behavioral symptoms, fronto-insulo-temporal atrophy, and apoE fragments and aggregates in the anterior cingulate cortex. ApoE formed complexes with TDP-43 that were more abundant in the apoE ?4 homozygote. Although differences seen in a sibling pair could arise due to chance, these findings raise the possibility that apoE4 exacerbates brain pathology in FTLD through formation of neurotoxic apoE fragments and interactions with TDP-43.     

血清载脂蛋白E在儿童感染性疾病中的变化

目的 探讨血清载脂蛋白E(ApoE)在儿童感染性疾病中的变化.方法 279例感染性疾病患儿中,脓毒症65例,化脓性脑膜炎47例,细菌性肺炎67例,无菌性脑膜炎47例,支原体肺炎53例.采用透射免疫比浊法(IA)检测感染性疾病患儿的血清ApoE水平.构建B组鼠伤寒沙门菌诱导的脓毒症小鼠模型,采用IA检测小鼠血清ApoE水平,实时荧光定量PCR和Western印迹法检测小鼠肝脏ApoE mRNA和蛋白的表达.两组间均数比较采用独立样本t检验.结果 血清ApoE在细菌性感染性疾病患儿中明显升高,在脓毒症患儿中高达(59.8±23.5) mg/L(t=-5.118,P＜0.01),在无菌性脑膜炎和支原体肺炎患儿中无明显变化.脓毒症小鼠模型血清ApoE水平明显升高,但肝脏ApoE mRNA和蛋白的表达下降,mRNA的相对值在造模后3h下降了71％(t=5.022,P＜0.01),在造模后24 h下降了73％(t=4.181,P＜0.01).结论 血清ApoE水平在细菌性感染性疾病中显著升高,而肝脏中ApoE表达下降,说明ApoE血清升高机制与肝脏表达不相关.     

载脂蛋白M基因启动子区域－778C→T置换对其表达的影响

目的构建含载脂蛋白M(ApoM)基因启动子区的荧光素酶报告基因的真核表达载体,探讨ApoM基因启动子区域-778C→T置换对ApoM表达的影响。方法采用PCR法扩增人染色体中含ApoM基因-1316 bp至+73 bp的DNA片段,筛选出含ApoM-778TT基因型(-778 bp无变异)及ApoM-778CT/CC基因型(-778bp变异)的DNA片段,构建含以上两个基因片段的PGL3重组载体。并采用阳离子脂质体转染法将携带萤火虫荧光素酶报告基因的重组质粒转染HepG2细胞,经48 h培养,检测荧光素酶的活性,以反映ApoM的表达水平。结果荧光素酶报告基因活性显示,ApoM-778C基因型携带者引起荧光素酶相对活性明显低于ApoM-778T基因型者。结论 ApoM基因启动子-778C→T对ApoM转录活性起抑制作用,它可能是影响ApoM基因表达的重要因素。     

非高密度脂蛋白胆固醇与载脂蛋白B在心血管疾病风险评估中的比较

非高密度脂蛋白胆固醇水平反映致动脉粥样硬化胆固醇总量,载脂蛋白B浓度反应致动脉粥样硬化颗粒总数。近期研究发现非高密度脂蛋白胆固醇和载脂蛋白B的心血管疾病风险预测价值优于传统指标低密度脂蛋白胆固醇。文章就这两个指标的心血管风险评估效能及临床操作性能做一综述。     

Apolipoprotein E s4 Allele and Outcomes of Traumatic Spinal Cord Injury

Abstract

Background/Objective: To test the hypothesis that apolipoprotein E (APOE) polymorphisms are associated with outcomes after spinal cord injury (SCI).

Methods: Retrospective cohort study, from rehabilitation admission to discharge.

Participants: Convenience sample of 89 persons with cervical SCI (C3-C8) treated from 1995 through 2003. Median age was 30 years (range 14-70); 67 were male (75%) and 83 were white (93%).

Main Outcome Measures: American Spinal Injury Association (ASIA) motor and sensory scores, ASIA Impairment Scale (AIS), time from injury to rehabilitation admission, and length of stay (LOS) in rehabilitation.

Results: Subjects with an APOE s4 allele (n = 15; 17%) had significantly less motor recovery during rehabilitation than did individuals without an s4 allele (median 3.0 vs 5.5; P < 0.05) and a longer rehabilitation LOS (median 106 vs 89 days; P = 0.04), but better sensory-pinprick recovery (median 5.0 vs 2.0; P = 0.03). There were no significant differences by APOE s4 allele status in sensory-light touch recovery, likelihood of improving AIS Grade, or time from injury to rehabilitation admission.

Conclusions: APOE ε4 allele was associated with differences in neurological recovery and longer rehabilitation LOS. Genetic factors may be among the determinants of outcome after SCI and warrant further study.     

聚合酶链反应限制性内切酶消化法检测人载脂蛋白E基因多态性

采用聚合酶链反应与限制性核酸内切酶ＨｈａＩ消化相结合的方法建立一种简便。实用的人载脂蛋白Ｅ基因多态性检测方法。ＰＣＲ扩增含有编码１１２和１５８位氨基酸的基因片断序列，产物经ＨｈａⅠ酶消化，经聚丙烯酸 胺凝胶电泳可见２－４条特定长度的ＤＮＡ条带易于判定ａｐｏＥ基因型。