Document Detail


Cholesterol efflux assay.
MedLine Citation:
PMID:  22414908     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Cholesterol content of cells must be maintained within the very tight limits, too much or too little cholesterol in a cell results in disruption of cellular membranes, apoptosis and necrosis. Cells can source cholesterol from intracellular synthesis and from plasma lipoproteins, both sources are sufficient to fully satisfy cells' requirements for cholesterol. The processes of cholesterol synthesis and uptake are tightly regulated and deficiencies of cholesterol are rare. Excessive cholesterol is more common problem. With the exception of hepatocytes and to some degree adrenocortical cells, cells are unable to degrade cholesterol. Cells have two options to reduce their cholesterol content: to convert cholesterol into cholesteryl esters, an option with limited capacity as overloading cells with cholesteryl esters is also toxic, and cholesterol efflux, an option with potentially unlimited capacity. Cholesterol efflux is a specific process that is regulated by a number of intracellular transporters, such as ATP binding cassette transporter proteins A1 (ABCA1) and G1 (ABCG1) and scavenger receptor type B1. The natural acceptor of cholesterol in plasma is high density lipoprotein (HDL) and apolipoprotein A-I. The cholesterol efflux assay is designed to quantitate the rate of cholesterol efflux from cultured cells. It measures the capacity of cells to maintain cholesterol efflux and/or the capacity of plasma acceptors to accept cholesterol released from cells. The assay consists of the following steps. Step 1: labelling cellular cholesterol by adding labelled cholesterol to serum-containing medium and incubating with cells for 24-48 h. This step may be combined with loading of cells with cholesterol. Step 2: incubation of cells in serum-free medium to equilibrate labelled cholesterol among all intracellular cholesterol pools. This stage may be combined with activation of cellular cholesterol transporters. Step 3: incubation of cells with extracellular acceptor and quantitation of movement of labelled cholesterol from cells to the acceptor. If cholesterol precursors were used to label newly synthesized cholesterol, a fourth step, purification of cholesterol, may be required. The assay delivers the following information: (i) how a particular treatment (a mutation, a knock-down, an overexpression or a treatment) affects the capacity of cell to efflux cholesterol and (ii) how the capacity of plasma acceptors to accept cholesterol is affected by a disease or a treatment. This method is often used in context of cardiovascular research, metabolic and neurodegenerative disorders, infectious and reproductive diseases.
Authors:
Hann Low; Anh Hoang; Dmitri Sviridov
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Video-Audio Media     Date:  2012-03-06
Journal Detail:
Title:  Journal of visualized experiments : JoVE     Volume:  -     ISSN:  1940-087X     ISO Abbreviation:  J Vis Exp     Publication Date:  2012  
Date Detail:
Created Date:  2012-03-14     Completed Date:  2012-05-29     Revised Date:  2014-03-12    
Medline Journal Info:
Nlm Unique ID:  101313252     Medline TA:  J Vis Exp     Country:  United States    
Other Details:
Languages:  eng     Pagination:  e3810     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Animals
Cell Line
Cholesterol / analysis*,  blood,  metabolism*
HeLa Cells
Hep G2 Cells
Humans
Macrophages / chemistry,  metabolism
Mice
Monocytes / chemistry,  metabolism
Tritium
Chemical
Reg. No./Substance:
10028-17-8/Tritium; 97C5T2UQ7J/Cholesterol
Comments/Corrections

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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