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Papers In Press, published online ahead of print March 1, 2008
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* Department of Medicine, Campus Charité Mitte, Humboldt University, Berlin, Germany
Center for Liver, Digestive and Metabolic Diseases, Laboratory of Pediatrics, University Medical Center Groningen, Groningen, The Netherlands
The online version of this article (available at http://www.jlr.org) contains supplementary data in the form of two figures.
Published, JLR Papers in Press, November 25, 2007.
1 To whom correspondence should be addressed. e-mail: u_tietge{at}yahoo.com
High density lipoprotein cholesterol represents a major source of biliary cholesterol. Secretory phospholipase A2 (sPLA2) is an acute phase enzyme mediating decreased plasma HDL cholesterol levels. Clinical studies reported a link between increased sPLA2 expression and the presence of cholesterol gallstones. The aim of our study was to investigate whether the overexpression of human sPLA2 in transgenic mice affects biliary cholesterol secretion and gallstone formation. Liver weight (P < 0.01) and hepatic cholesterol content (P < 0.01) were significantly increased in sPLA2 transgenic mice compared with controls as a result of increased scavenger receptor class B type I (SR-BI)-mediated hepatic selective uptake of HDL cholesterol (P < 0.01), whereas hepatic SR-BI expression remained unchanged. However, biliary cholesterol secretion as well as fecal neutral sterol and fecal bile salt excretion remained unchanged in sPLA2 transgenic mice. Furthermore, gallstone prevalence in response to a lithogenic diet was identical in both groups. These data demonstrate that i) increased flux of cholesterol from HDL into the liver via SR-BI as a result of phospholipase modification of the HDL particle translates neither into increased biliary and fecal sterol output nor into increased gallstone formation, and ii) increased sPLA2 expression in patients with cholesterol gallstones might be a consequence rather than the underlying cause of the disease.
Supplementary key words inflammation reverse cholesterol transport high density lipoprotein scavenger receptor class B type I
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