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Macrophage Foam Cells

  1. Annabel F Valledor1,
  2. Jorge Lloberas2,
  3. Antonio Celada2

Published Online: 15 SEP 2010

DOI: 10.1002/9780470015902.a0020730

eLS

eLS

How to Cite

Valledor, A. F., Lloberas, J. and Celada, A. 2010. Macrophage Foam Cells. eLS. .

Author Information

  1. 1

    University of Barcelona, School of Biology, Spain

  2. 2

    Institute for Research in Biomedicine (IRB Barcelona)-University of Barcelona, Spain

Publication History

  1. Published Online: 15 SEP 2010

This is not the most recent version of the article. View current version (16 FEB 2015)

Abstract

Foam cells are lipid-loaded macrophages that are generated from the massive uptake of modified low-density lipoproteins and the intracytoplasmatic accumulation of cholesteryl esters. Foam cells are present in all stages of atherosclerosis and participate in inflammatory responses and tissue remodelling within the arterial intima. Foam cells can also be generated as a consequence of infection by persistent pathogens, such as Mycobacterium, Chlamydia and Toxoplasma. These pathogens meet nutritional advantages by residing within cells that accumulate lipids. When the immune system is unable to eliminate substances perceived as foreign, it produces a granuloma, composed mostly of macrophages, attempting to wall off the nonself-material. This article reviews the processes that lead to the regulation of foam cell formation in atherosclerosis and infection.

Key Concepts:

  • Foam cells are lipid-loaded macrophages.

  • Foam cells are generated from the massive uptake of modified low-density lipoproteins and the intracytoplasmatic accumulation of cholesteryl esters.

  • Foam cells are present in several diseases as atherosclerosis and as result of different infections.

  • Foam cells participate in inflammatory responses and tissue remodelling.

  • Endothelial transmigration of monocytes is the first step in the development of atherosclerosis.

  • Once monocytes have taken residence in the arterial wall intima, they undergo phenotypic transformation into macrophages, and can internalise large amounts of modified LDLs and become foam cells.

  • Liver X receptors (LXR) and the retinoid X receptors (RXR) heterodimers directly upregulate the expression of a number of genes involved in lipid and lipoprotein homeostasis.

  • When the immune system is unable to eliminate substances that it perceives as foreign it attempts to wall off the nonself-material by producing granulomas; a ball-like structures composed of immune cells, mostly activated macrophages, that are surrounded by lymphocytes predomintantly of the TH1 type.

Keywords:

  • foam cells;
  • granuloma;
  • low-density lipoproteins;
  • liver X receptors (LXRs);
  • macrophages;
  • nuclear receptors;
  • peroxisome proliferator-activated receptors (PPARs);
  • retinoid X receptors (RXR);
  • tuberculosis