Sweeney G, Nazir D, Clarke C, Goettsche G
Department of Medicine, Faculty of Health Sciences, McMaster University, Hamilton, Ont.
Clin Invest Med. 1996 Aug;19(4):243-50.
To establish methods to examine the polar lipids of triglyceride-rich lipoproteins (TRLs) and to examine postprandial changes in glycerophosphocholine (PC) and glycerophosphoethanolamine (PE) polar lipids and in the ratio of diacyl to alkenylacyl components. The membrane phospholipids of TRLs have received little attention. PC and PE constitute major fractions and both comprise diacyl- and alkenylacyl-phospholipids. There has been recent interest in possible antioxidant properties of alkenylacyl (plasmalogen) PE.
Analysis of PE and PC fractions in blood samples taken from the subjects while fasting and at four 2-h intervals after eating a 4749-kJ breakfast.
Five healthy subjects.
Levels of PE and PC fractions isolated from blood samples by ultracentrifugation (to isolate the d < 1.006 fraction of plasma) and reversed-phase chromatography.
The concentration of triglyceride in particles of density less than 1.006 g/cm2 in the samples increased rapidly, peaking 4 h after the meal at 0.51 mmol/L above the fasting level. Apolipoprotein B-48 was maximal in the sample taken 2 h after eating and below 1%, as a percentage of apolipoproteins B-48 and B-100, in all other samples. The concentration of PC exceeded that of PE by an order of magnitude, but there was a proportionately greater increase in PE postprandially. PE contained a rapidly cleared alkenylacyl fraction, which was maximal (at a threefold increase over the baseline level) in the sample taken 4 h after eating.
As blood triglyceride levels rise and fall postprandially, the polar lipid composition of the TRLs also changes; these changes are more marked in the PE than in the PC fraction. The fact that the level of the PE fraction peaked later (at 4 h after eating) than that of B-48 apolipoprotein (which peaked at 2 h after eating) suggests that the peak in the PE fraction had a hepatic (very-low-density lipoprotein) origin. Alkenylacyl (plasmalogen) phospholipid accompanied both PE and PC fractions but was about 10 times greater in PE. This result is significant if alkenylacyl PE does indeed function as an antioxidant.
建立检测富含甘油三酯脂蛋白（TRLs）极性脂质的方法，并检测餐后甘油磷酸胆碱（PC）和甘油磷酸乙醇胺（PE）极性脂质以及二酰基与烯基酰基成分比例的变化。TRLs的膜磷脂很少受到关注。PC和PE构成主要部分，且都包含二酰基磷脂和烯基酰基磷脂。最近人们对烯基酰基（缩醛磷脂）PE可能具有的抗氧化特性产生了兴趣。
对受试者在空腹时以及食用一顿4749千焦早餐后每隔2小时采集的血样中的PE和PC组分进行分析。
5名健康受试者。
通过超速离心（分离血浆中密度小于1.006的部分）和反相色谱法从血样中分离出的PE和PC组分的水平。
样本中密度小于1.006 g/cm2颗粒中的甘油三酯浓度迅速升高，餐后4小时达到峰值，比空腹水平高0.51 mmol/L。载脂蛋白B - 48在进食后2小时采集的样本中含量最高，在所有其他样本中，其占载脂蛋白B - 48和B - 100的百分比低于1%。PC的浓度比PE高一个数量级，但餐后PE的增加幅度相对更大。PE含有一个快速清除的烯基酰基部分，在进食后4小时采集的样本中达到最大值（比基线水平增加了两倍）。
随着餐后血甘油三酯水平的上升和下降，TRLs的极性脂质组成也会发生变化；这些变化在PE中比在PC组分中更为明显。PE组分的水平峰值出现时间比载脂蛋白B - 48（在进食后2小时达到峰值）晚（在进食后4小时），这表明PE组分的峰值源于肝脏（极低密度脂蛋白）。烯基酰基（缩醛磷脂）磷脂同时伴随着PE和PC组分，但在PE中的含量约为PC的10倍。如果烯基酰基PE确实具有抗氧化功能，那么这一结果具有重要意义。
