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KMID : 0391419940040020158
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Korean Journal of Lipidology
1994 Volume.4 No. 2 p.158 ~ p.169
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Changes of Fibroblast LDL Receptor in Polygenic Hypercholesterolemia and Characterization of LDL Receptor of Chorionic Villi and Amniotic Fluid Cells
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신현호
박정배/한인권/김영설/배종화/최영길
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Abstract
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Biochemical, genetic, ad ultrastructural studies have demonstrated that the cell surface of cultured human fibroblasts contains receptors for low density lipoprotein (LDL), the major cholesterol transport protein in human plasma. In normal cells
the
binding of LDL to its receptor constitute the initial step in a process by which the lipoprotein is transported into the cell through adsorptive endocytosis. Inside the cell, LDL is hydrolyzed within lysosome and its cholesterol is made available
for
metabolic utilization.
In familial hypercholesterolemia(FH) the absence or deficiency of LDL receptors blocks the degradation of lipoprotein so that it accumulates in plasma to levels that much more higher than normal.
The very high plasma LDL in familiar or polygenic hypercholesterolemia patients produces precocious atherosclerosis. It therefore becomes important to establish the diagnosis of hypercholesterolemia at the earliest age.
In the current studies, we describe an assay for 125I-LDL binding to membranes prepared from human fibroblasts, chorionic villi and amniotic fluid cells.
1) The LDL receptor concentrations in fibroblast cells from subjects with severe polygenic hypercholesterolemia (plasma cholesterol>250mg/dl) were more increased than those from normal control(plasma cholesterol <200 mg/dl) and subjects with
moderate
polygenic hypercholesterolemia(220mg/dl< piasma cholesterol level <250 mg/dl).
2) The LDL receptor bindings in fibroblast from subjects with polygnic hyperchole sterolemia and normal cholesterol level were positively correlated with plasma cholesterol level.
3) The LDL receptor surface binding and internalization in the fibroblast cells were increased in polygenic hypercholesterolemia patients than subjects with normal cholesterol level.
4) like fibroblasts, cultured chorionic villi and amniotic fluid cells expressed LDL receptor.
5) In cultured fibroblast cells, LDL receptor bindings of 5 hour incubation with 125I-LDL were more decreased than those of 3hr incubation.
6) In cultured fibroblast and chorionic villi cells, LDL receptor bindings of 4℃incubation were more increased than those of 37℃ incubation.
These findings indicate that LDL receptor binding are increased in polygeic hypercholesterolemia to compensate the increased plasma cholesterol level and the expression of LDL receptors in chorionic villi and amniotic fluid cells are useful for
the
prenatal diagnosis of homozygous familial hypercholesterolemia.
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