高胆固醇摄入对组织胆固醇含量和脂质向高密度脂蛋白转移的影响。

Impact of high cholesterol intake on tissue cholesterol content and lipid transfers to high-density lipoprotein.

机构信息

Lipid Metabolism Laboratory, Heart Institute (InCor), Medical School Hospital, University of São Paulo, São Paulo, Brazil.

出版信息

Nutrition. 2011 Jun;27(6):713-8. doi: 10.1016/j.nut.2010.07.018. Epub 2010 Oct 8.

DOI:10.1016/j.nut.2010.07.018

PMID:20934854

Abstract

OBJECTIVE

Esterified cholesterol is the storage form of cholesterol in the organism. High-density lipoprotein (HDL), where free cholesterol is transferred from other lipoproteins and tissues, is the main esterification site in plasma. The aim of this study was to investigate how high cholesterol intake changes free/esterified ratios of cholesterol in the plasma, aorta, liver and lipid transfers to HDL.

METHODS

Twenty male Golden Syrian hamsters fed 0.5% cholesterol for 15 wk and 19 controls without cholesterol feeding were sacrificed to determine serum lipids, transfer proteins (cholesteryl ester transfer protein and phospholipid transfer protein), and amount of free and esterified cholesterol in the aorta and liver. In vitro transfer of radioactive free and esterified cholesterol, phospholipids, and triacylglycerols to HDL was performed by incubating whole plasma with an artificial nanoemulsion used as a lipid donor and measuring radioactivity in the HDL fraction after chemical precipitation of non-HDL fractions and of the nanoemulsion.

RESULTS

Compared with controls, cholesterol-fed animals showed a 137% increase in non-HDL plasma fraction and a 61% increase in HDL (P < 0.001). The esterified/free cholesterol ratio in non-HDL and HDL fractions did not change. In the aorta, free cholesterol increased 55% and the esterified/free ratio (0.2) decreased. Cholesterol accumulation in the liver was several-fold greater and esterified/free increased (1.3). Cholesterol feeding pronouncedly increased the transfer of free and esterified cholesterol, phospholipids, and triacylglycerols to HDL and cholesteryl ester transfer protein and phospholipid transfer protein activities.

CONCLUSIONS

Free cholesterol is cytotoxic and less stable than esterified cholesterol, and the present data on how the organism responds to high cholesterol intake with respect to esterified/free ratios in the plasma, aorta, liver, and lipid transfers to HDL may have physiopathologic implications.

摘要

目的

胆固醇酯是机体中胆固醇的储存形式。高密度脂蛋白（HDL）是游离胆固醇从其他脂蛋白和组织转移的主要酯化部位。本研究旨在探讨高胆固醇摄入如何改变血浆、主动脉、肝脏中游离/酯化胆固醇的比值以及胆固醇向 HDL 的脂质转移。

方法

20 只雄性金黄地鼠喂食 0.5%胆固醇 15 周，19 只对照鼠不喂食胆固醇，处死测定血清脂质、转移蛋白（胆固醇酯转移蛋白和磷脂转移蛋白）以及主动脉和肝脏中游离和酯化胆固醇的量。通过用人工纳米乳液孵育全血浆，将放射性游离和酯化胆固醇、磷脂和三酰基甘油转移至 HDL，纳米乳液用作脂质供体，并在非 HDL 级分和纳米乳液的化学沉淀后测量 HDL 级分中的放射性。

结果

与对照鼠相比，喂食胆固醇的动物的非 HDL 血浆级分增加了 137%，HDL 增加了 61%（P < 0.001）。非 HDL 和 HDL 级分中的酯化/游离胆固醇比值没有变化。在主动脉中，游离胆固醇增加了 55%，酯化/游离比值（0.2）降低。肝脏中的胆固醇积累增加了数倍，酯化/游离比值增加（1.3）。胆固醇喂养明显增加了游离和酯化胆固醇、磷脂和三酰基甘油向 HDL 的转移以及胆固醇酯转移蛋白和磷脂转移蛋白的活性。