Asn291Ser和Lys312insC联合突变脂蛋白脂酶蛋白功能研究

通过脂蛋白脂酶基因敲除杂合子(LPL~(+/-))小鼠体内实验.探讨Asn291Ser和Lys312insC联合突变(Asn291Ser+Lys312insC)脂蛋白脂酶的功能改变.结果示LPL~(+/-)小鼠甘油三酯、游离脂肪酸、血糖、体重均较c57小鼠高(均P<0.05),而其肝脏、骨骼肌及脂肪脂蛋白脂酶mRNA表达较c57显著降低(P<0.01),Western印迹实验进一步显示LPL~(+/-)小鼠各组织脂蛋白脂酶蛋白表达较c57低.注射Asn291Ser+Lys312insC脂蛋白脂酶后血脂及脂蛋白脂酶活性变化不明显,而注射野生型脂蛋白脂酶后小鼠游离脂肪酸、甘油三酯显著降低(P<0.05).本研究证实Ash291Ser+Lys312insC联合突变的脂蛋白脂酶活性降低,调脂功能受损.     

丙丁酚对动脉粥样硬化小鼠抗氧化作用的比较

目的观察丙丁酚对高脂高胆固醇饲养的C57BL/6J小鼠和载脂蛋白E基因缺陷(载脂蛋白E-/-)小鼠抗氧化作用的影响,比较丙丁酚对两种小鼠的作用差异。方法以高脂高胆固醇饲料饲喂小鼠,制作高脂血症模型。采用酶比色法及相关检测试剂盒分别测定小鼠血脂水平及与氧化应激相关的指标;采用双抗夹心ELISA法测定氧化型低密度脂蛋白的水平;采用改良的Eckerson方法测定对氧磷酶1的活性,采用逆转录聚合酶链式反应检测对氧磷酶1mRNA的表达。结果与两种小鼠各自的基础饲料组比较,高脂高胆固醇组血脂水平均有升高;与各自的高脂高胆固醇组比较,丙丁酚处理后,C57BL/6J小鼠血清的甘油三酯、总胆固醇、高密度脂蛋白胆固醇和低密度脂蛋白胆固醇水平分别降低了41.0%、43.6%、44.8%和41.3%(P<0.05),载脂蛋白E-/-小鼠血清的甘油三酯、总胆固醇、高密度脂蛋白胆固醇和低密度脂蛋白胆固醇水平,分别降低了36.2%、28.2%、31.3%、33.9%(P<0.05)。小鼠主动脉内膜的动脉粥样硬化病变与各自高脂高胆固醇组比较,C57BL/6J小鼠经丙丁酚处理后病变面积减少了61.1%,载脂蛋白E-/-小鼠经丙丁酚处理后病变面积减少了27.2%(P<0.05)。与各自基础饲料组比较,高脂血症小鼠丙二醛及氧化型低密度脂蛋白的水平增高,而总抗氧化能力和超氧化物歧化酶水平降低(P<0.05);与各自的高脂高胆固醇组比较,丙丁酚处理组小鼠的总抗氧化能力和超氧化物歧化酶水平上升,丙二醛及氧化型低密度脂蛋白的水平则降低(P<0.05)。两组小鼠高脂高胆固醇组血清对氧磷酶1的活性较基础饲料组均下降,经高脂饮食加丙丁酚处理后对氧磷酶1活性比单纯高脂饮食组有所增加;肝脏对氧磷酶1mRNA的表达在高脂高胆固醇组下调,而丙丁酚处理组则上调(P<0.05)。结论丙丁酚可以减轻高脂血症小鼠动脉粥样硬化病变,减轻高脂高胆固醇饮食诱导的氧化应激,而载脂蛋白E基因缺陷则一定程度减弱丙丁酚的上述作用。     

RNAi介导的脂联素基因沉默对ApoE基因敲除小鼠糖脂代谢的影响

探讨脂联素基因表达缺陷对ApoE基因敲除(ApoE~(-/-))小鼠糖脂代谢的影响.注射短发卡RNA(shRNA)腺病毒后高脂喂养的ApoE~(-/-)小鼠(ADI组)血浆脂联素水平明显低于普食喂养(NF)、单纯高脂喂养(HF)和空载腺病毒高脂对照组(GF,均P<0.01).3组高脂喂养的APOE~(-/-)小鼠体重、空腹血糖、血浆游离脂肪酸、总胆固醇、甘油三酯、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)和血浆胰岛素水平明显高于NF组(均P<0.01),而ADI组与HF和GF组相比,游离脂肪酸、总胆同醇、甘油三酯、LDL-C、HDL-C和血浆胰岛素水平增高更为明显(P<0.01或P<0.05),提示长期高脂饲养和脂联素基因表达缺陷使ApoE~(-/-)小鼠具备较为典型的糖脂代谢紊乱和胰岛素抵抗的病理生理表现.     

高脂血症人群血清胆固醇酯转运蛋白的水平

目的分析不同高脂血症人群血清胆固醇酯转运蛋白水平及其对血浆各脂蛋白间脂质转运的调节作用。方法脂蛋白电泳结合酶显色法分别检测血清各脂蛋白中的甘油三酯含量;酶联免疫吸附试验测定血清胆固醇酯转运蛋白和氧化型低密度脂蛋白水平;分析胆固醇酯转运蛋白与脂质水平间的相关性。结果高甘油三酯组、高胆固醇组、混合组和对照组中胆固醇酯转运蛋白水平分别为1.89±1.32、2.37±1.30、2.33±1.73和1.58±1.00 mg/L,与对照组比较,高甘油三酯组变化无显著性(P>0.05),高胆固醇组(P<0.01)和混合组均升高(P<0.05)。高脂血症人群高密度脂蛋白中胆固醇/甘油三酯比值降低;高甘油三酯组和混合组低密度脂蛋白中甘油三酯/胆固醇比值升高,高胆固醇组无差别,其中高甘油三酯组变化程度最大,混合组次之,高胆固醇组最小;且胆固醇酯转运蛋白水平与上述比值相关。高脂血症人群血清氧化型低密度脂蛋白水平升高,与低密度脂蛋白中甘油三酯/胆固醇比值高度呈正相关。结论高脂血症人群胆固醇酯转运蛋白水平升高,促进了脂蛋白间脂质转运,使高密度脂蛋白和低密度脂蛋白脂质组成发生变化,促进了动脉粥样硬化的发生和发展。     

普罗布考与阿托伐他汀合用对急性冠状动脉综合征的调脂及抗氧化作用

目的 观察普罗布考与阿托伐他汀联合治疗对急性冠状动脉综合征患者血脂、血清氧化型低密度脂蛋白水平及对氧磷酶1活性的影响.方法 38例急性冠状动脉综合征患者随机分为对照组(n=20,阿托伐他汀10mg/d)和治疗组(n=18,阿托伐他汀10 mg/d+普罗布考1 000 mg/d),随访4周.两组在治疗前后分别测定血清总胆固醇、低密度脂蛋白胆固醇、高密度脂蛋白胆固醇、甘油三酯、血清氧化型低密度脂蛋白水平及对氧磷酶1活性.结果 治疗4周后,对照组低密度脂蛋白胆固醇降低15.4%、高密度脂蛋白胆固醇上升13.7%(P<0.05),血清总胆固醇、甘油三酯略有下降但未达到统计学意义(P>0.05);治疗组血清总胆固醇、低密度脂蛋白胆固醇、高密度脂蛋白胆固醇、甘油三酯分别下降28.1%、28.5%、14.2%(P<0.01)和23.3%(P<0.05);与对照组相比,治疗组血清总胆固醇、低密度脂蛋白胆固醇和高密度脂蛋白胆固醇下降更为明显(P<0.01).治疗后,两组血清氧化型低密度脂蛋白水平均明显降低,对氧磷酶1活性均明显升高(P<0.01);而治疗组血清氧化型低密度脂蛋白水平和对氧磷酶1活性的变化比对照组更为明显(P<0.01).治疗前的血清氧化型低密度脂蛋白水平、对氧磷酶活性及两者治疗后的变化值与血脂各指标之间均无相关关系(P>0.05),而对氧磷酶活性与血清氧化型低密度脂蛋白水平呈显著负相关(r=-0.669,P<0.01).结论 阿托伐他汀与普罗布考合用具有协同降胆固醇作用和抗氧化作用,但普罗布考降高密度脂蛋白胆固醇的作用不能被阿托伐他汀抵消.     

胆固醇酯转移蛋白TaqIB基因多态性与辛伐他汀对冠心病患者血脂调节作用的关系

目的:探讨胆固醇酯转移蛋白TaqlB基因多态性与辛伐他汀对冠状动脉(冠脉)粥样硬化性心脏病患者血脂调节作用的关系.方法:对147例急性冠脉综合征(ACS组)患者、99例稳定冠心病(组)患者及42例经冠脉造影排除冠心病的患者(对照组)进行研究.采用酶法测定血脂各项水平,采用多聚酶链反应一限制性内切酶片段长度多态性分析冠心病患者胆固醇酯转移蛋白基因中TaqlB基因多态性.冠心病患者予辛伐他汀调脂3个月后复查血脂.采用方差分析法比较TaqIB基因组间调脂疗效有无差异.结果:血浆血脂水平变化:可见ACS组与稳定冠心病组血浆总胆固醇、低密度脂蛋白胆固醇及脂蛋白(a)水平明显高于对照组,差异有统计学意义(P<0.05～0.01).辛伐他汀调脂治疗前后对冠心病患者血脂水平的影响:可见经辛伐他汀治疗3个月后,血浆总胆固醇、低密度脂蛋白胆固醇、甘油三酯(仅B282)、脂蛋白(a)(tZ BlB2)水平较治疗前均降低,差异有统计学意义(P<0.05～0.01).冠心病患者胆固醇酯转移蛋白TaqIB基因型与等位基因对辛伐他汀调脂作用的影响:132132组患者经辛伐他汀调脂治疗后,血浆甘油三酯有了显著降低,且与B1携带者(包括B182组和B1B1组)差异有统计学意义(P<0.01).结论:基因型B182与B1B1比较,血浆高密度脂蛋白胆固醇水平显著增高.B2B2患者经辛伐他汀调脂治疗后,血浆甘油三酯水平显著降低.提示辛伐他汀对冠心病患者的血脂调节作用与胆固醇酯转移蛋白Taq IB基因多态性具有相关性.     

高脂喂养对ApoE-/-小鼠脂肪细胞因子的影响

目的 探讨高脂诱导胰岛素抵抗(IR)对ApoE-/-小鼠内脂素(Visfatin)和脂联素的影响.方法 健康雄性ApoE-/-小鼠,随机分为普食组(NF)和高脂喂养组(HF),共喂养16 w.采用以3-H3葡萄糖为示踪剂的高胰岛素-正糖钳夹评价糖代谢变化.用实时荧光定量PCR测定肝和脂肪组织细胞因子Visfatin和脂联素mRNA表达水平,采用Western印迹法测定肝、脂肪组织及血浆Visfatin蛋白水平.结果 HF组小鼠空腹血糖、血浆胰岛素、胆固醇、游离脂肪酸、甘油三酯、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)水平明显升高(均P<0.01).胰岛素钳夹术中,HF组葡萄糖输注率(GIR)明显低于NF组,肝糖生成率(HGP)明显高于NF组(均P<0.01).HF组小鼠肝脏Visfatin和脂联素mRNA表达水平以及脂肪组织Visfatin mRNA表达水平明显低于NF组(P<0.01和P<0.05);HF组血浆、肝脏和脂肪组织Visfatin蛋白表达也显著降低均(均P<0.01).结论 高脂喂养的ApoE-/-小鼠具备明显的IR基本特征,可能与脂肪细胞因子的改变有关.     

胰岛素改善糖尿病小鼠骨髓内皮祖细胞动员障碍研究

目的:探讨胰岛素对糖尿病小鼠骨髓内皮祖细胞(EPC)动员的影响及其机制.方法:链脲霉素诱导C57BL/6雄鼠糖尿病,随机分为非糖尿病组、糖尿病组和糖尿病胰岛素治疗组(胰岛素组)3组(各组n=32).入组小鼠饲养2个月后行左侧股动脉高位结扎离断术造成急性单侧后肢缺血模型.胰岛素组皮下注射胰岛素控制血糖.流式细胞术检测术后(0,1,3,7天,n=6-10)外周血单个核细胞中干细胞因子受体/干细胞抗原-1/胎肝激酶-1阳性早期EPC比例.酶联免疫吸附法测定血浆及骨髓血管内皮生长因子(VEGF)及间充质衍生因子1α(SDF-1α)水平.免疫印迹法测定骨髓VEGF、蛋白激酶B、内皮一氧化氮合酶及基质金属蛋白酶-9的蛋白表达及磷酸化水平,酶谱法测定基质金属蛋白酶-9酶活性.结果:糖尿病组呈现缺血诱导的骨髓EPC动员障碍,动员高峰期其外周血早期EPC数量较非糖尿病组显著减少(P<0.01);并伴随血浆及骨髓VEGF及SDF-1α释放减少(P<0.01);骨髓VEGF蛋白表达受抑制、蛋白激酶B与内皮一氧化氮合酶磷酸化减弱及基质金属蛋白酶-9酶活性受损(P<0.05),差异均有统计学意义.胰岛素组缺血术后骨髓EPC动员能力、VEGF及SDF-1α释放水平及骨髓蛋白激酶B/内皮一氧化氮合酶/基质金属蛋白酶-9信号通路活化水平较糖尿病组均明显提高(P<0.05),差异均有统计学意义.结论:胰岛素改善糖尿病动物缺血诱导的骨髓EPC动员障碍,这种作用可能通过恢复受损的SDF-1α/VEGF信号通路活化而介导.     

姜黄素对食饵性高脂血症大鼠血浆脂蛋白代谢相关酶活性的影响

为了探讨姜黄素降血脂、抗动脉粥样硬化可能的酶学机理．用高脂膳食喂饲Wistar大鼠4周，造成食饵性高脂血症，然后用高、低两种剂量的姜黄素和阳性对照药血脂康、非诺贝特进行实验性治疗。给药3周后处死动物，比较治疗前后血清和肝脏总胆固醇及甘油三酯含量、血清高密度脂蛋白胆固醇和低密度脂蛋白胆固醇含量，同时测定血浆卵磷脂胆固醇酰基转移酶、肝素化血浆总脂解酶、脂蛋白脂酶和肝脂酶活性。结果发现，高、低剂量姜黄素、非诺贝特和血脂康均能使血清总胆固醇、甘油三酯和低密度脂蛋白胆固醇含量降低，降甘油三酯作用高剂量姜黄素和非诺贝特最优，降总胆固醇和低密度脂蛋白胆固醇作用低剂量姜黄素和血脂康最优，高剂量姜黄素和非诺贝特能增加高密度脂蛋白胆固醇含量，同时能降低肝脏总胆固醇和甘油三酯含量。高、低剂量姜黄素能显著提高血浆卵磷脂胆固醇酰基转移酶活性．降低血浆游离胆固醇含量，高、低剂量姜黄素和非诺贝特能提高血浆总脂解酶和脂蛋白脂酶活性，高剂量姜黄素还能显著提高肝脂酶活性。结果提示，姜黄素具有明显的降低肝脏和血清脂质的作用，可能与提高血浆脂蛋白代谢相关酶的活性有关。     

脂蛋白脂酶和冠心病

脂蛋白脂酶是富含甘油三酯酯蛋白代谢的关键酶,与动脉粥样硬化有密切关系。脂蛋白脂酶基因多态性影响血浆甘油三酯和高密度脂蛋白水平,与冠心病的发生有一定联系;脂蛋白脂酶可促进泡沫细胞形成;转基因动物模型显示其具有抗动脉粥样硬化作用;临床冠心病患者脂蛋白脂酶活性降低。     

Glucocorticoids and triglyceride transport: effects on triglyceride secretion rates, lipoprotein lipase, and plasma lipoproteins in the rat.

In order to elucidate the mechanism(s) of hyperlipidemia following glucocorticoid administration, dexamethasone (0.125 mg/Kg) was administered daily intramuscularly for 2 wk to male Sprague-Dawley rats and the effects on plasma triglyceride (TG) and cholesterol (Chol), lipoprotein neutral lipids, hepatic triglyceride secretion rates (TGSR; Triton), and epididymal fat lipoprotein lipase (LPL) were determined. Special measures were taken to maintain positive caloric balance and keep the weights of control and dexamethasone-treated animals comparable. Significant increases (p less than 0.001) in TG and very-low density lipoprotein (VLDL) triglyceride associated with no change in Chol and actual reduction in both triglyceride and cholesterol in low density lipoprotein (ldl) were observed in the steroid-treated animals. Dexamethasone treatment was associated with increased basal insulin and glucose levels, an insignificant increment in TGSR, and a highly significant reduction (p less than 0.001) in LPL. These findings suggest that glucocorticoid treatment increases splanchnic triglyceride production rates, but the resulting hypertriglyceridemia is primarily a consequence of impaired VLDL removal due to low adipose tissue LPL activity.     

Lipoprotein Lipase Activator NO‐1886

Lipoprotein lipase (LPL) is a rate‐limiting enzyme that hydrolyzes circulating triglyceride‐rich lipoproteins such as very low‐density lipoproteins and chylomicrons. A decrease in LPL activity is associated with an increase in plasma triglycerides (TG) and a decrease in plasma high‐density lipoprotein cholesterol (HDL‐C). The increase in plasma TG and decrease in plasma HDL‐C are risk factors for cardiovascular disease. Tsutsumi et al. hypothesized that elevating LPL activity would cause a reduction of plasma TG and an increase in plasma HDL‐C, resulting in protection against the development of atherosclerosis. To test this hypothesis, Otsuka Pharmaceutical Factory, Inc. synthesized the LPL activator NO‐1886. NO‐1886 increased LPL mRNA and LPL activity in adipose tissue, myocardium and skeletal muscle, resulting in an elevation of postheparin plasma LPL activity and LPL mass in rats. NO‐1886 also decreased plasma TG concentration and caused a concomitant rise in plasma HDL‐C. Long‐term administration of NO‐1886 to rats and rabbits with experimental atherosclerosis inhibited the development of atherosclerotic lesions in coronary arteries and aortas. Multiple regression analysis suggested that the increase in plasma HDL‐C and the decrease in plasma TG protect from atherosclerosis. The atherogenic lipid profile is changed to an antiatherogenic profile by increasing LPL activity, resulting in protection from atherosclerosis. Therefore, the LPL activator NO‐1886 or other possible LPL activating agents are potentially beneficial for the treatment of hyper‐triglyceridemia, hypo‐HDL cholesterolemia, and protection from atherosclerosis.     

Role of macrophage-derived lipoprotein lipase in lipoprotein metabolism and atherosclerosis

Lipoprotein lipase (LPL) synthesis by macrophages is upregulated in early atherogenesis, implicating the possible involvement of LPL in plaque formation. However, it is still unclear whether macrophage-derived LPL displays a proatherosclerotic or an antiatherosclerotic role in atherosclerotic lesion development. In this study, the role of macrophage-derived LPL on lipid metabolism and atherosclerosis was assessed in vivo by transplantation of LPL-deficient (LPL-/-) and wild-type (LPL+/+) bone marrow into C57BL/6 mice. Eight weeks after bone marrow transplantation (BMT), serum cholesterol levels in LPL-/--->C57BL/6 mice were reduced by 8% compared with those in LPL+/+-->C57BL/6 mice (P:<0.05, n=16), whereas triglycerides were increased by 33% (P:<0.05, n=16). Feeding the mice a high-cholesterol diet increased serum cholesterol levels in LPL-/--->C57BL/6 and LPL+/+-->C57BL/6 mice 5-fold and 9-fold, respectively, resulting in a difference of approximately 50% (P:<0. 01) after 3 months on the diet. No effects on triglyceride levels were observed under these conditions. Furthermore, serum apolipoprotein E levels were reduced by 50% in the LPL-/--->C57BL/6 mice compared with controls under both dietary conditions. After 3 months on a high-cholesterol diet, the atherosclerotic lesion area in LPL-/--->C57BL/6 mice was reduced by 52% compared with controls. It can be concluded that macrophage-derived LPL plays a significant role in the regulation of serum cholesterol, apolipoprotein E, and atherogenesis, suggesting that specific blockade of macrophage LPL production may be beneficial for decreasing atherosclerotic lesion development.     

郑州地区汉族糖尿病合并冠心病患者脂蛋白脂酶多态性

目的探讨脂蛋白脂酶(LPL)在2型糖尿病和糖尿病合并冠心病发病中的作用机制。方法测定糖尿病和糖尿病合并冠心病患者外周血白细胞LPL内含子6的PvuⅡ和内含子8的HindⅢ多态性,以及血清中甘油三酯(TG)、胆固醇(TC)、高密度脂蛋白胆固醇(HDL-c)等的水平。结果糖尿病及糖尿病合并冠心病患者外周血LPL基因PvuⅡ和HindⅢ的等位基因P、H频率与对照组相比较无显著性差异。糖尿病和糖尿病合并冠心病患者LPL基因PvuⅡ多态性中的P ／P 基因型患者的TG、TC和LDL-c水平高于非P ／P 患者和对照组,HDL—c水平低于非P ／P 患者和对照组。结论LPL基因PvuⅡ突变位点与糖尿病合并冠心病患者体内脂质代谢紊乱有关,可通过了解LPL基因多态性以了解糖尿病和糖尿病合并冠心病脂质代谢紊乱的状况。     

Lipoprotein lipase activator NO-1886 improves fatty liver caused by high-fat feeding in streptozotocin-induced diabetic rats

NO-1886 is a lipoprotein lipase (LPL) activator. Administration of NO-1886 results in an increase in plasma high-density lipoprotein cholesterol (HDL-C) and a decrease in plasma triglyceride (TG) levels. The aim of this study was to ascertain whether NO-1886 improves fatty liver caused by high-fat feeding in streptozotocin (STZ)-induced diabetic rats. Administration of NO-1886 resulted in increased plasma HDL-C levels and decreased TG levels without affecting total cholesterol and glucose levels in the diabetic rats. NO-1886 dose-dependently decreased liver TG contents and cholesterol contents, resulting in improvement of fatty liver. NO-1886 also reduced plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) that accompany fatty liver. The liver cholesterol contents were inversely correlated with plasma HDL-C levels (r = -0.5862, P <.001) and were positively correlated with plasma TG levels (r = 0.4083, P <.003). The liver TG contents were inversely correlated with plasma HDL-C levels (r = -0.6195, P <.001) and were positively correlated with plasma TG levels (r = 0.5837, P <.001). There was no correlation between plasma cholesterol levels, and cholesterol and TG contents in liver. These results indicate that reducing plasma TG levels and elevating in HDL-C levels may result in improving fatty liver.     

遗传性混合型高脂血症小鼠的自发性动脉粥样硬化

目的为探讨高甘油三酯血症对动脉粥样硬化的影响,建立了脂蛋白脂肪酶和载脂蛋白E双基因缺陷的混合型高甘油三酯和高胆固醇血症动物模型。方法比较了双基因以及载脂蛋白E基因缺陷小鼠的血浆甘油三酯,总胆固醇和高密度脂蛋白胆固醇的水平,并对整条主动脉和主动脉流出道进行了动脉粥样硬化病变定量检测。结果发现双基因缺陷小鼠血浆甘油三酯是载脂蛋白E基因缺陷小鼠的3.8倍(5.904±0.505比1.536±0.860g/L),血浆总胆固醇也略有增加,但高密度脂蛋白胆固醇则无明显差异。两种小鼠的主动脉全长及流出道均有明显的粥样硬化,斑块面积占全部动脉的37.2%±10.7%比44.6%±18.1%,但之间无显著差异。结论载脂蛋白E基因缺陷合并脂蛋白脂肪酶缺陷虽然可以出现血浆甘油三酯增高,但动脉粥样硬化病变并没有加重。这可能与血管壁局部脂蛋白脂肪酶的活性相应降低而对动脉粥样硬化抑制作用有关。     

高脂血症性急性胰腺炎脂蛋白脂酶基因多态性研究

目的 探讨三酰甘油分解代谢酶脂蛋白脂酶(LPL)的表达和基因多态性与高脂血症性急性胰腺炎(HLP)的相关性.方法 2005年5月至2006年12月HLP住院患者20例,急性胰腺炎患者50例,另选取血脂正常患其他疾病者50例为对照.测定血清三酰甘油(TG)、胆固醇(Ch)、游离脂肪酸(FFA)、脂蛋白数值、血清LPL/肝脂酶(HL)活性;RT-PCR检测LPL mRNA表达;聚合酶链-限制性酶切片段多态性分析(PCR-RFLP)法分析LPL基因内含子8 Hind Ⅲ基因多态性变化.结果 HLP组血清TG、胆固醇(Ch)和FFA测定值均显著高于AP组和对照组,差异均有统计学意义(P值均<0.05);HLP组ApoE值显著高于AP组和对照组(P<0.05);HLP组高密度脂蛋白(HDL)显著低于对照组(P<0.05).HLP组LPL值为(5.98±2.28)U/L,均显著高于AP组和对照组[(1.97±0.76)U/L和(1.04±0.53)U/L,P值分别=0.046和0.031];HLP组HL值为(8.15±2.86)U/L,均显著高于AP组和对照组(1.64±0.59)U/L和(0.86±0.39)U/L,P值分别=0.002和0.001].HLP组LPL mRNA表达高于AP组,差异有统计学意义(P=0.0325).LPL基因内含子8 Hind Ⅲ分析,H2等位基因频率HLP组显著高于对照组(0.90比0.72,P<0.05);H1等位基因频率在HLP和AP组均显著低于对照组(0.10比0.28和0.14比0.28,P<0.05).HLP组H2H2基因型患者TG和Apo E值均显著高于H2H1/H1H1基因型(P值分别=0.043和0.046);AP组H2H2基因型患者TG值显著高于H2H1/H1H1基因型(P=0.032).结论 HLP患者LPL Hind Ⅲ H2等位基因频率显著高于正常人群,主要与高三酰甘油血症(HTG)相关,而与胰腺炎无关;且H2H2基因型的HLP患者血清TG、ApoE值高于其他基因型者.HTG可引起LPL基因和蛋白表达活性增高,加速TG大量分解代谢和FFA等分解产物蓄积,是诱发和加重HLP的中心环节和重要病理生理机制.     

Complete rescue of lipoprotein lipase-deficient mice by somatic gene transfer of the naturally occurring LPLS447X beneficial mutation

The naturally occurring human lipoprotein lipase S447X variant (LPLS447X) exemplifies a gain-of function mutation with significant benefits including decreased plasma triglycerides (TG), increased high-density lipoprotein (HDL) cholesterol, and reduced risk of coronary artery disease. The S447X variant may be associated with higher LPL catalytic activity; however, in vitro data supporting this hypothesis are contradictory. We wanted to investigate the in vivo mechanism by which the LPLS447X variant improves the lipid profile of S447X carriers. We conducted a functional assessment of human LPLS447X compared with LPLWT in mice. LPL variants were compared in the absence of endogenous mouse LPL in newborn LPL(-/-) mice by adenoviral-mediated gene transfer. LPL(-/-) mice normally exhibit severe hypertriglyceridemia and die within 48 hours of birth. LPLWT gene transfer prolonged the survival of mice up to 21 days. In contrast, LPLS447X completely rescued 95% of the mice to adulthood and increased LPL catalytic activity in postheparin plasma 2.1-fold compared with LPLWT at day 3 (P=0.003). LPLS447X also reduced plasma TG 99% from baseline (P<0.001), 2-fold more than LPLWT, (P<0.01) and increased plasma HDL cholesterol 2.9-fold higher than LPLWT (P<0.01). These data provide in vivo evidence that the increased catalytic activity of LPLS447X improves plasma TG clearance and increases the HDL cholesterol pool compared with LPLWT.     

树鼩脂蛋白脂肪酶的cDNA克隆、组织分布及活性测定

目的了解不易感动脉粥样硬化动物树鼠句的脂蛋白脂肪酶的结构和活性特点,并与其它种属比较,探讨脂蛋白脂肪酶在树鼠句独特脂代谢中的作用。方法以树鼠句脂肪细胞mRNA反转录获得的cDNA一链为模板,应用SMART-RACE技术获得树鼠句脂蛋白脂肪酶的cDNA序列并推导出其氨基酸序列;实时定量PCR方法检测树鼠句脂蛋白脂肪酶mRNA在各组织中的分布;真核表达树鼠句和人脂蛋白脂肪酶蛋白,放射性同位素法测定二者的活性并比较。结果树鼠句脂蛋白脂肪酶cDNA序列全长为3293bp,其中编码区1437bp,编码20个氨基酸的信号肽和458个氨基酸的成熟蛋白,该成熟蛋白N-端比人脂蛋白脂肪酶多10个氨基酸。树鼠句脂蛋白脂肪酶与其它哺乳类动物的氨基酸序列同源性大于90%,功能域高度保守。树鼠句脂蛋白脂肪酶的组织表达谱比较广泛,在心肌和脂肪组织中大量表达,但在骨骼肌中未检测到,却在肝脏中有中低水平表达,与人脂蛋白脂肪酶在这两种组织中的表达相反。活性测定结果显示,树鼠句脂蛋白脂肪酶活性显著高于人(7.67倍),这与测定的树鼠句血浆低甘油三酯水平相符。结论树鼠句的高活性脂蛋白脂肪酶可能是其血浆低水平甘油三酯的主要原因。