血脂与脂蛋白是什么
先认识“血脂”:血液里的脂类
我们体检报告上常见的“血脂”,指的是血液中的一类脂质(lipid / blood lipids,Lipid (blood lipids)脂质(血脂) · Lipid (blood lipids)/ˈlɪpɪd/血液中脂类物质的统称,涵盖胆固醇、甘油三酯及磷脂等;临床上最重要的两种是胆固醇和甘油三酯。因不溶于水,需借助脂蛋白在血液中运输。A general term for the fatty substances in blood, including cholesterol, triglycerides and phospholipids; the two clinically most relevant are cholesterol and triglycerides. Being water-insoluble, they must be transported in blood by lipoproteins.🧩 词根拆解 / word rootslip-脂、脂肪 · fat希腊语 lipos 脂肪+-id(化学)某类物质 · a substance of a class (chemistry))。 它是一个统称,涵盖胆固醇、甘油三酯和磷脂等,其中临床上最重要的两种就是胆固醇和甘油三酯。
[1]Tier 1Joint Committee for the Development of Chinese Guidelines for the Management of Blood Lipids et al. 2023 Chinese guideline for lipid management (English full text). Frontiers in Pharmacology 2023doi:10.3389/fphar.2023.1190934- 胆固醇(cholesterol,Cholesterol胆固醇 · Cholesterol/kəˈlɛstərɒl/一种脂质分子,是细胞膜、类固醇激素和胆汁酸的必需成分;因不溶于水,需由脂蛋白在血液中运输。A lipid molecule essential for cell membranes, steroid hormones, and bile acids; being water-insoluble, it must be transported in the blood by lipoproteins.🧩 词根拆解 / word rootschole-胆汁(最早从胆结石中分离) · bile希腊语 kholē 胆汁+stere(o)-固体、坚硬 · solid/stiff希腊语 stereos 固体+-ol醇(化学后缀,表示这是一种醇) · an alcohol (chemistry))是细胞膜、激素和胆汁酸的必需原料。
- 甘油三酯(triglyceride,TG甘油三酯 · TriglycerideTG/traɪˈɡlɪsəraɪd/由一分子甘油与三分子脂肪酸结合成的脂质,是人体主要的储能脂质,也是两大血脂之一;在血液中主要由乳糜微粒和 VLDL 运输。A lipid formed from one glycerol molecule bound to three fatty acids; the body's main energy-storage lipid and one of the two principal blood lipids, transported in blood mainly by chylomicrons and VLDL.🧩 词根拆解 / word rootstri-三 · three希腊语 treis 三+glyceride甘油酯(甘油与脂肪酸形成的酯) · an ester of glycerolglycerol 甘油 + -ide)是人体主要的储能脂质,是身体重要的“燃料库”。[1]Tier 1Joint Committee for the Development of Chinese Guidelines for the Management of Blood Lipids et al. 2023 Chinese guideline for lipid management (English full text). Frontiers in Pharmacology 2023doi:10.3389/fphar.2023.1190934
一个矛盾:脂类不溶于水,血液却是水
这里有一个基础却关键的矛盾:血液的主要成分是水,而脂类不溶于水。 指南明确指出,脂质不溶于水,必须与一种特殊的蛋白质——载脂蛋白(apolipoprotein)结合, 形成脂蛋白(lipoprotein,Lipoprotein脂蛋白 · Lipoprotein/ˌlaɪpoʊˈproʊtiːn/由脂质与载脂蛋白(apolipoprotein)组成的球状颗粒,是脂质在血液中运输的载体;按密度可分为乳糜微粒、VLDL、IDL、LDL、HDL,以及 Lp(a)。A spherical particle made of lipids and apolipoproteins that serves as the vehicle for transporting lipids in blood; classified by density into chylomicrons, VLDL, IDL, LDL, HDL, and additionally Lp(a).🧩 词根拆解 / word rootslipo-脂、脂肪 · fat希腊语 lipos 脂肪+protein蛋白质 · protein希腊语 prōtos 第一/首要)之后,才能溶入血液、被运输到各组织进行代谢。
[1]Tier 1Joint Committee for the Development of Chinese Guidelines for the Management of Blood Lipids et al. 2023 Chinese guideline for lipid management (English full text). Frontiers in Pharmacology 2023doi:10.3389/fphar.2023.1190934打个比方:脂类就像不能直接丢进水里的“货物”,脂蛋白则是把货物包好、能在血液这条“河”里漂浮运输的 快递包裹。
图 · 脂质不溶于水,需与载脂蛋白结合成脂蛋白,才能溶入血液被运输。[1]Tier 1Joint Committee for the Development of Chinese Guidelines for the Management of Blood Lipids et al. 2023 Chinese guideline for lipid management (English full text). Frontiers in Pharmacology 2023doi:10.3389/fphar.2023.1190934
脂蛋白:怎样给“包裹”分类
血液里的脂蛋白不止一种。指南按密度把它们分为:乳糜微粒(chylomicron, CM)、极低密度脂蛋白 (very low-density lipoprotein,VLDL极低密度脂蛋白 · Very low-density lipoproteinVLDL/ˌvɛri loʊ ˈdɛnsɪti ˌlaɪpoʊˈproʊtiːn/由肝脏合成、以甘油三酯为主(TG 约占 50%–65%)的脂蛋白,是含 apoB 的致动脉粥样硬化脂蛋白之一;在代谢中可进一步转变为 IDL 与 LDL。A liver-synthesised, triglyceride-rich lipoprotein (TG ~50%–65%); one of the apoB-containing atherogenic lipoproteins, which can be further metabolised into IDL and LDL.🧩 词根拆解 / word rootsvery-low-density极低密度 · very low density+lipo-脂、脂肪 · fat希腊语 lipos 脂肪+protein蛋白质 · protein希腊语 prōtos 第一/首要)、中密度脂蛋白(IDL)、低密度脂蛋白 (low-density lipoprotein,LDL低密度脂蛋白 · Low-density lipoproteinLDL/ˌloʊ ˈdɛnsɪti ˌlaɪpoʊˈproʊtiːn/运输胆固醇进入外周组织的脂蛋白颗粒;其携带的胆固醇称 LDL-C,是动脉粥样硬化的核心致病因素,俗称“坏胆固醇”。The lipoprotein particle that carries cholesterol to peripheral tissues; its cholesterol cargo (LDL-C) is a central causal driver of atherosclerosis, popularly called 'bad cholesterol'.🧩 词根拆解 / word rootslow-density低密度 · low density+lipo-脂、脂肪 · fat希腊语 lipos 脂肪+protein蛋白质 · protein希腊语 prōtos 第一/首要)和高密度脂蛋白(high-density lipoprotein, HDL高密度脂蛋白 · High-density lipoproteinHDL/ˌhaɪ ˈdɛnsɪti ˌlaɪpoʊˈproʊtiːn/参与胆固醇逆向转运的脂蛋白颗粒,俗称“好胆固醇”;但用药物单纯升高 HDL-C 并未被证明能降低心血管风险。The lipoprotein involved in reverse cholesterol transport, popularly called 'good cholesterol'; however, pharmacologically raising HDL-C alone has not been shown to reduce cardiovascular risk.🧩 词根拆解 / word rootshigh-density高密度 · high density+lipo-脂、脂肪 · fat希腊语 lipos 脂肪+protein蛋白质 · protein希腊语 prōtos 第一/首要);此外还有一类特殊的脂蛋白叫脂蛋白(a)〔Lp(a)〕。[1]Tier 1Joint Committee for the Development of Chinese Guidelines for the Management of Blood Lipids et al. 2023 Chinese guideline for lipid management (English full text). Frontiers in Pharmacology 2023doi:10.3389/fphar.2023.1190934
不同“包裹”装的货物侧重不同:
- 乳糜微粒是血液中最大、密度最低的脂蛋白,主要成分是甘油三酯;VLDL 由肝脏合成,其甘油三酯含量 约占 50%–65%——所以这两类是富含甘油三酯的脂蛋白。[1]Tier 1Joint Committee for the Development of Chinese Guidelines for the Management of Blood Lipids et al. 2023 Chinese guideline for lipid management (English full text). Frontiers in Pharmacology 2023doi:10.3389/fphar.2023.1190934
- LDL 颗粒中约有 50% 是胆固醇,是血液中胆固醇含量最高的脂蛋白,因此被称为富含胆固醇的脂蛋白, 负责把胆固醇运往外周组织。[1]Tier 1Joint Committee for the Development of Chinese Guidelines for the Management of Blood Lipids et al. 2023 Chinese guideline for lipid management (English full text). Frontiers in Pharmacology 2023doi:10.3389/fphar.2023.1190934
换句话说,“胆固醇”和“甘油三酯”是货物,“LDL、VLDL、HDL……”是运货物的不同包裹——报告单上这两组词 描述的其实是不同层面的东西。