Hepatic lipase activity and high density lipoproteins in familial hypercholesterolemia: adaptational mechanisms for LDL-receptor deficient state.
With a view toward elucidating the poorly understood high density lipoprotein (HDL) metabolism in familial hypercholesterolemic (FH) patients, the activities of the plasma enzymes involved in HDL metabolism; hepatic triglyceride lipase (HTGL), lipoprotein lipase (LPL) and lecithin-cholesterol acyltransferase (LCAT) with concomitant determination of HDL particle size, were analyzed in 50 age-matched hypercholesterolemic patients (26 FH and 24 non-FH patients). The activity of HTGL in FH patients was significantly higher (p less than 0.02) than in non-FH patients. The analysis of HDL size by gradient gel electrophoresis showed significantly smaller HDL particles in FH patients. Analysis of the correlation between HTGL activity and HDL particle size confirmed that the variation in HDL particle size was related to HTGL activity. Those results suggest that the differences in HTGL activity and HDL size between the familial and non-familial types of hypercholesterolemia may be due to differences in their pathophysiology. The high HTGL activity and small HDL particles in FH probably are the consequences of an adaptational mechanism used by LDL-receptor-deficient hepatocytes to increase the intracellular pool of cholesterol.
Moriguchi
E H
EH
First Department of Internal Medicine, School of Medicine, Tokai University, Japan.
Tamachi
H
H
Goto
Y
Y
D000222:Adaptation, Physiological; D006801:Humans; D006938:Hyperlipoproteinemia Type II / Q000378:metabolism*; D008049:Lipase / Q000032:analysis / Q000378:metabolism*; D008071:Lipoprotein Lipase / Q000378:metabolism; D008075:Lipoproteins, HDL / Q000097:blood*; D008077:Lipoproteins, LDL / Q000378:metabolism*; D008099:Liver / Q000201:enzymology*; D007862:Phosphatidylcholine-Sterol O-Acyltransferase / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism*; D018110:Receptors, Lipoprotein
D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D011956:Receptors, Cell Surface; D018110:Receptors, Lipoprotein; D007862:Phosphatidylcholine-Sterol O-Acyltransferase; D008049:Lipase; D008071:Lipoprotein Lipase