Journal of Lipid Research
Volume 48, Issue 10, October 2007, Pages 2162-2171
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Research Article
Serum amyloid P colocalizes with apolipoproteins in human atheroma: functional implicationss⃞

https://doi.org/10.1194/jlr.M700098-JLR200Get rights and content
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Serum amyloid P (SAP) is a common component of human amyloid deposits and has been identified in atherosclerotic lesions. We investigated the extent of the colocalization of SAP with apolipoprotein A-I (apoA-I), apoB, apoC-II, and apoE in human coronary arteries and explored potential roles for SAP in these regions, specifically the effect of SAP on the rate of formation and macrophage recognition of amyloid fibrils composed of apoC-II. Analysis of 42 human arterial sections by immunohistochemistry and double label fluorescence microscopy demonstrated that SAP and apoA-I, apoB, apoC-II, and apoE were increased significantly in atherosclerotic lesions compared with nonatherosclerotic segments. SAP colocalized with all four apolipoproteins to a similar extent, whereas plaque macrophages were found to correlate most strongly with apoC-II and apoB. In vitro studies showed that SAP accelerated the formation of amyloid fibrils by purified apoC-II. Furthermore, SAP strongly inhibited the phagocytosis of apoC-II amyloid fibrils by primary macrophages and macrophage cell lines and blocked the resultant production of reactive oxygen species. The ability of SAP to accelerate apoC-II amyloid fibril formation and inhibit macrophage recognition of apoC-II fibrils suggests that SAP may modulate the inflammatory response to amyloid fibrils in atherosclerosis.

atherosclerosis
macrophage
immunohistochemistry
amyloid

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Published, JLR Papers in Press, July 13, 2007.

s⃞

The online version of this article (available at http://www.jlr.org) contains supplementary data in the form of five figures.