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. Author manuscript; available in PMC: 2012 May 10.
Published in final edited form as: J Invest Dermatol. 2009 Dec 24;130(3):661–670. doi: 10.1038/jid.2009.411

Figure 1. Illustration of the proposed “metabolic hypothesis” of PXE.

Figure 1

Under physiologic conditions, the ABCC6 protein is expressed in high levels in the liver and serves as an efflux pump on the baso-lateral surface of hepatocytes transporting critical metabolites from the intracellular milieau to the circulation (right side of the panel). In the absence of ABCC6 transporter activity in PXE, reduced concentrations of such substrate molecules, which may serve as physiologic anti-mineralization factors, are found in the circulation, resulting in mineralization of connective tissues in a number of organs, such as the eye, the arterial blood vessels, the kidneys and the skin (middle panel). The presence of mineralization is illustrated by histopathologic examination (Alizarin red stain) of tissues in Abcc6-/- mice that recapitulate the features of human PXE. (Modified from Jiang and Uitto, 2006, with permission).