HDL biology
Hepatic lipase shrinks HDL particles only when VLDL and CETP are both present, and lipoprotein lipase blocks the effect (Atherosclerosis 1990)
Original title: Lipoprotein lipase prevents the hepatic lipase-induced reduction in particle size of high density lipoproteins during incubation of human plasma
Human plasma lipoproteins or whole plasma were incubated in vitro with canine hepatic lipase (HL) and bovine milk lipoprotein lipase (LPL) to determine their effects on HDL particle size. HL preferentially hydrolyzed HDL triacylglycerol while LPL hydrolyzed mainly VLDL triacylglycerol, but neither lipase altered HDL particle size unless both VLDL and CETP were also present in the incubation. Under those conditions, HL promoted a marked, VLDL-triacylglycerol-concentration-dependent reduction in HDL particle size, while LPL alone had virtually no effect; when LPL and HL were combined, LPL prevented the HL effect. The authors conclude that hepatic lipase directly reduces HDL particle size through a process dependent on concurrent CETP-mediated lipid transfer between HDL and VLDL, and that lipoprotein lipase counteracts this by lowering VLDL triacylglycerol concentration.
Original abstract
Human plasma lipoproteins or human whole plasma have been incubated in vitro with canine hepatic lipase (HL) and bovine milk lipoprotein lipase (LPL) to determine the effects of lipases on the particle size distribution of HDL. Confirming previous reports, HL preferentially hydrolysed high density lipoprotein (HDL) triacylglycerol while LPL hydrolysed predominantly very low density lipoprotein (VLDL) triacylglycerol; however, neither lipase altered HDL particle size unless both VLDL and cholesteryl ester transfer protein (CETP) were present. Under these conditions HL promoted marked reduction in HDL particle size in a process dependent on the concentration of VLDL triacylglycerol while LPL was virtually without effect. When both LPL and HL were included in the same incubation, however, LPL prevented the effects of HL. These results are consistent with a proposition that HL has a direct effect on HDL particle size in a process which is dependent on concurrent lipid transfers between HDL and VLDL and that LPL reduces the effect of HL by reducing the concentration of VLDL triacylglycerol.
Summary written by cetpinhibition.org from the published abstract; figures as published. Page updated 19 August 2026. Methods.