APOLIPOPROTEIN-E AND LIPOPROTEIN-LIPASE CO-ORDINATELY ENHANCE BINDINGAND UPTAKE OF CHYLOMICRONS BY HUMAN HEPATOCYTES

ApoE and LpL are important in the metabolism of triglyceride rich lipo proteins, and defects in either or both may result in hyperlipidaemia. It has previously been shown that ApoE and LPL specifically enhance c ellular catabolism of lipoproteins by various cell lines. The authors determine in this paper the effect of ApoE and LpL on chylomicron and LDL binding and uptake by human hepatocytes in primary culture. Separa te addition of ApoE and LpL greatly enhanced binding and uptake of chy lomicrons. Simultaneous addition of ApoE and LPL further increased chy lomicron uptake in an additive way. For LDL a different situation was observed: neither ApoE nor LPL mediated a significant increase of lipo protein uptake. The authors conclude that ApoE and LpL co-ordinately e nhance binding and uptake of chylomicrons by primary human hepatocytes . The effect appears to be independent of LDL receptors and the co-ord inate effect of ApoE and LPL may be important for normal chylomicron c atabolism.