【作者】 田丽；

【导师】 傅明德；

【作者基本信息】 四川大学 ， 生物化学与分子生物学， 2007， 硕士

【摘要】 Ⅰ.载脂蛋白AI水平与HDL亚类分布关系的研究背景与目的：载脂蛋白AI是高密度脂蛋白（HDL）中主要的蛋白质，它是细胞胆固醇逆向转运（RCT）的特殊重要因素。ApoAI能与磷脂，多种血浆因子及细胞膜受体结合，可以激活卵磷脂胆固醇酰基转移酶（LCAT），起着促进细胞内胆固醇的移出，酯化，转移，以及调节HDL代谢的作用。本研究旨在探讨载脂蛋白水平主要是apoAI的水平对HDL亚类分布的影响。方法：采用双向电泳-免疫印迹检测法分析了545例受试者血浆HDL亚类的组成及含量。应用在受试人群呈正态分布的apoAI含量均值加或减一个标准差作为分割点将受试者分为3组即低apoAI组（apoAI≤1043．6mg/L）、中间apoAI组（1043．6＜apoAI＜1452．6mg/L）和高apoAI组（apoAI≥1452．6mg/L）。结果：1．与低apoAI水平组比较，中间及高apoAI水平组受试者所有HDL亚类的含量均逐渐显著的增加（p＜0．01～p＜0．001）。并且在高apoAI水平组，大颗粒的HDL_2b含量的增加较其小颗粒的preβ₁-HDL含量的增加更明显。2．当apoAI及HDL-C水平同时升高时，高apoAI-HDL-C组较低apoAI-HDL-C组，其HDL_2b的含量增加116％，而preβ₁-HDL含量却仅仅增加了26％。3．两两相关分析发现，apoAI水平与所有HDL亚类显著正相关，多元线性回归分析显示，apoAI水平为HDL亚类分布改变最有力的预测指标。结论：1．随血浆apoAI水平升高，所有HDL亚类，其含量都逐渐显著增加，尤其是大颗粒的HDL_2b最为明显。2．当apoAI及HDL-C水平同时增加时，HDL向大颗粒转变更加明显。表明HDL成熟代谢过程加强，胆固醇逆向转运作用增强。3．血浆apoAI水平是影响HDL亚类分布的的重要因素。Ⅱ．血浆apoAⅡ含量对于HDL亚类分布的影响背景与目的：载脂蛋白AⅡ（apoAⅡ）是HDL颗粒中第二种主要的载脂蛋白，约占HDL中蛋白质总量的20％；apoAⅡ除了作为HDL的结构成份之外，还具有抑制卵磷脂胆固醇酯酰基转移酶（LCAT）及激活肝酯酶（HL）的作用。但是，ApoAⅡ与HDL亚类分布关系的研究却鲜有报道。本研究探讨血浆apoAⅡ含量对HDL亚类分布的影响，并分析apoAⅠ、apoAⅡ含量同时增加时，HDL亚类组成、分布所发生的变化。方法：采用双向电泳-免疫印迹检测法分析了292例受试者血浆HDL亚类的组成及含量。应用在受试人群呈正态分布的apoAⅠ和或apoAⅡ含量均值加或减一个标准差作为分割点把受试者分为低apoAⅡ组（apoAⅡ≤232．4mg/L）、中间apoAⅡ组（232．4＜apoAⅡ＜331．2mg/L）、高apoAⅡ组（apoAⅡ≥331．2mg/L）以及低apoAⅠ-apoAⅡ组（apoAⅠ≤1024．2mg/L及apoAⅡ≤232．4mg/L）、中间apoAⅠ-apoAⅡ组（1024．2＜apoAⅠ＜1446．6mg/L及232．4＜apoAⅡ＜331．2mg/L）和高apoAⅠ-apoAⅡ组（apoAⅠ≥1446．6mg/L及apoAⅡ≥331．2mg/L）。结果：1．与低apoAⅡ组比较，高apoAⅡ组HDL_3a，HDL_3b，和HDL_2b的含量显著增加（p＜0．01，p＜0．01，p＜0．01）。2．当apoAⅠ及apoAⅡ水平同时增加时，所有HDL亚类的含量均逐渐显著升高。并且，高apoAⅠ-apoAⅡ组受试者HDL_2b的含量较低apoAⅠ-apoAⅡ组增加115％，preβ₁-HDL的含量仅增加了39％，HDL_2b含量增加更为明显。3．两两相关以及多元回归分析均显示，血浆apoAⅠ水平与所有HDL亚类呈显著正相关，然而血浆apoAⅡ水平则仅与HDL₃及HDL₂呈正相关。结论：1．血浆apoAⅡ含量增多不仅可以引起大颗粒的HDL_2b含量的增加，而且可以导致小颗粒的HDL₃积聚。提示apoAⅡ水平在HDL颗粒成熟代谢的过程中可能起着双重的作用。2．当apoAⅠ及apoAⅡ水平同时升高时，大颗粒HDL_2b的含量增加更为明显，表明HDL成熟代谢近一步增强。Ⅲ．肥胖患者血浆HDL亚类分布的研究背景与目的：肥胖者以血浆TG水平升高、HDL-C水平降低为特征，与AS和CHD的发生密切相关。研究发现新生缺脂的小颗粒preβ₁-HDL从外周摄取胆固醇并在各种血浆因子，如卵磷脂-胆固醇酰基转移酶（LCAT）、胆固醇酯转运蛋白（CETP）、磷脂转运蛋白（PLTP）等的参与下，按preβ₁-HDL→preβ₂-HDL→preβ₃-HDL→HDL₃→HDL₂递变过程成熟，逐步转变为富含胆固醇酯的HDL₂从而被运至肝脏进一步降解。因此，HDL亚类组成、含量及分布变化与RCT有密切关系。本研究分析肥胖患者血浆HDL亚类的分布特征，为阐明HDL亚类组成、分布与肥胖人群As及CHD的发生机制提供新的依据。方法：采用双向电泳-免疫印迹检测法分析了581例中国人群血浆HDL亚类组成及含量。依据中国肥胖问题工作组推荐的体重指数（BMI）的标准，将受试者分为超轻组（BMI＜18．5kg/m²），合适组（BMI18．5-24kg/m²），超重组（24＜BMI≤28kg/m²）以及肥胖组（BMI＞28kg/m²）共四组。结果：1．与体重合适者比较，肥胖患者TG、preβ₁-HDL含量显著升高（p＜0．01，p＜0．01），而HDL-C、HDL_2a、HDL_2b含量显著降低（p＜0．01，p＜0．05，p＜0．01）。2．随血清BMI的升高，preβ₁-HDL含量显著逐渐增加，而HDL_2b含量显著逐渐减少（p＜0．01，p＜0．01）。3．HDL颗粒变小的趋势在超重及肥胖患者中随着TG水平的升高更加明显。4．两两相关分析揭示，超重及肥胖患者血浆TG、BMI与preβ₁-HDL含量显著正相关（p＜0．01），与HDL_2b含量显著负相关（p＜0．01）。5．多元线性回归分析发现，TG含量与高水平的preβ₁-HDL呈独立正相关而，与低水平的HDL_2b呈独立负相关。结论：超重者及肥胖患者血浆HDL颗粒呈变小趋势，而且这种趋势随血浆TG、BMI特别是TG水平升高更加明显。提示超重者及肥胖患者血浆HDL成熟代谢过程受阻，胆固醇逆向转运作用减弱。更多还原

【Abstract】 Part One Relationship between apolipoprotein concentrations and HDL subclasses distributionBackground: Alterations in plasma apolipoproteins levels can influence the composition, content, and distribution of plasma lipoproteins that affect the risk of atherosclerosis. This study assessed the relationship between plasma apolipoproteins levels, mainly apoAI, and HDL subclass distribution.Methods: The contents of plasma HDL subclasses were determined by 2-dimensional gel electrophoresis coupled with immunodetection in 545 Chinese subjects. We make use of the apoAI mean plus or minus 1 SD, So, the subjects were further subdivided into low apoAI group （apoAI≤1043.6mg/L）, middle apoAI（1043.6＜apoAI＜1452.6） and high apoAI（apoAI≥1452.6mg/L） respectively.Results: Compared with low apoAI group, the contents of all HDL subclasses increased significantly both in middle and high apoAI group, and the contents of large-sized HDL_2b increased more significantly relative to those of small-sized preβ₁-HDL in high apoAI group. Meanwhile, when apoAI and HDL-C levels increased simultaneously, in comparison to low apoAI along with HDL-C concentration group, a significant increased （116%） was shown in HDL_2b but only a slight increase （26%） in preβ₁-HDL. In addition, Pearson correlation analysis revealed that apoAI levels were positively and significantly correlated with all HDL subclasses. Multiple liner regression presented the apoAI concentrations were the most powerful predictor for HDL subclasses distribution.Conclusion: With the elevation of apoAI concentrations, the contents of all HDL subclasses increased successively and significantly, especially, an increased in large-sized HDL2b. Further, when apoAI and HDL-C concentrations increased simultaneously, the shift to larger HDL size was more obvious. Which, in turn, indicated that HDL maturation might be enhanced and, the reverse cholesterol transport might be strengthened along with apoAI levels might be a more powerful factor to influence the distribution of HDL subclasses.Part Two The influence of apolipoproteinAII concentrations on HDL subclasses distributionBackground: To investigate the impact of plasma apoAⅡconcentrations on the alteration of HDL subclasses distribution. And the cooperative effect of apoAⅠand apoAⅡon it.Methods: The contents of plasma HDL subclasses were quantities by two-dimensional gel electrophoresis associated with immunodetection in 292 Chinese subjects. These subjects were divided into low apoAII （apoAⅡ≤232.4mg/L）, middle apoAⅡ（232.4＜apoAⅡ＜331.2mg/L）, high apoAII （apoAⅡ≥331.2mg/L） groups, low apoAⅠ-AⅡlevels （apoAⅠ≤1024.2mg/L together with apoAⅡ≤232.4mg/L）, middle apoAⅠ-AⅡlevels （1024.2＜apoAⅠ＜1446.6mg/L together with 232.4＜apoAⅡ＜331.2mg/L） and high apoAⅠ-AⅢevels（apoAⅠ≥1446.6mg/L together with apoAⅡ≥331.2mg/L）groups according to the mean plus or minus 1 SD of apoAⅡor apoAⅠlevels as two cut-points.Results: compared to the low apoAⅡgroup, the contents of HDLaa, HDLab, and HDL2b increased strikingly in high apoAⅡgroup. Moreover, the contents of all HDL subclasses increased progressively and significantly when apoAⅠand apoAⅡlevels increased simultaneously, and in comparison to low apoAⅠ-AⅡlevels group, the contents of large-sized nOL2b （115%）increased more significantly than those of small-sized preβ₁-HDL （39%） in high apoAⅠ-AⅡlevels group. In addition, Pearson correlation along with multiple liner regression results revealed that apoAI was positively and significantly correlated with all HDL subclasses while apoAII only showed positive association with HDL_3a, HDL_3b and HDL_2b.Conclusion: excess apoAⅡcan cause the accumulation of both large-sized HDL_2b and small-sized HDL₃. Which implied that apoAII play a double role in the HDL maturation metabolism. Meanwhile, large-sized HDL_2b increased significantly when apoAI and apoAⅡlevels elevated simultaneously.Part Three Alterations of High Density Lipoprotein Subclasses in Obese SubjectsBackground: To investigate the characteristics of lipid metabolism in obese subjects, with particular emphasis on the alteration of HDL subclass contents and distribution.Methods: Apo-AⅠcontents of serum HDL subclasses were quantitated by two-dimensional gel electrophoresis in 581 Chinese individuals. According to the BMI which the Working Group on Obesity in China （W G O C） under the support of International life sciences focal point in China recommend criterion, the subjects were divided into four groups: underweight group（BMI＜18.5kg/m²）,desirable group （BMI18.5-24kg/m²）, overweight group （24＜BMI≤28kg/m²） and obesity group （BMI＞28kg/m²）.Results: Concentrations of triglyceride, apoA-Ⅰcontent of preβ₁-HDL were significantly higher （P＜0.01 and P＜0.01, respectively）, but, the levels of HDL-C, apoA-Ⅰcontents of HDL_2a, HDL_2b were significantly lower （P＜0.01, P＜0.05 and P＜0.01, respectively） in obesity subjects versus desirable subjects. Moreover, with the elevation of BMI, small-sized preβ₁-HDL increased gradually and significantly, while large-sized HDL_2b decreased gradually and significantly in population. Meanwhile, the variations of HDL subclasses distribution above mentioned were more obvious with the elevation of TG levels in obesity along with overweight subjects. Pearson correlation analysis revealed that BMI, TG were positively correlated with preβ₁-HDL but negatively correlated with HDL_2b and multiple regression analysis also showed that TG concentrations were associated independently and positively with high pre_β1-HDL; while correlated independently and negatively with low HDL_2b in obesity along with overweight subjects.Conclusions: The particle size of HDL shifted toward smaller size in obesity and overweight subjects. Of note, the shift was more obvious with the elevation of BMI, especially TG levels. Which, in turn, indicated that HDL maturation might be abnormal, and reverse cholesterol transport might be weakened.更多还原