Heparan sulfate lipoproteins metabolism

The rationale for this type of contrast agent is to use the endogenous metabolic pathway of lipid metabolism in the liver for the transport of iodinated substances. Chylomicron remnants are naturally occurring lipoproteins in the blood that are responsible for the transport of lipids into the liver. Three different mechanisms for this transport are discussed direct uptake by the low-density lipoprotein receptor transport to the low-density lipoprotein receptor-related protein (LRP) mediated by heparan sulfate proteoglycan (HSPG) or direct HSPG-LRP uptake and direct HSPG uptake. One of the prerequisites for particles to be transported by these mechanisms is a mean diameter of less than 100-300 run. 

R.W. Mahley and Z.S. Ji, Remnant lipoprotein metabolism key pathways involving cell-surface heparan sulfate proteoglycans and apolipoprotein E, J. Lipid Res. 40 (1999) 1-16. 

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