Biomaterial Database

Identification of low density lipoprotein receptor abnormalities by assaying functional receptors on proliferating lymphocytes. 1989

J A Cuthbert, and P E Lipsky

Department of Internal Medicine, University of Texas Health Science Center, Southwestern Medical School, Dallas 75235.

Lymphocyte proliferation stimulated by mitogenic lectins is dependent on exogenously supplied cholesterol when endogenous cholesterol synthesis is blocked with the specific inhibitor mevinolin. Lymphocytes from patients homozygous for familial hypercholesterolemia (FH) lack low density lipoprotein (LDL) receptors, and, therefore, these patients cannot use LDL cholesterol to support proliferation when endogenous sterol synthesis is blocked. Thus, LDL receptors are required for the uptake of exogenous lipoprotein cholesterol by proliferating lymphocytes. As a result, the number of functional receptors can be assessed when endogenous sterol synthesis is inhibited and when limiting concentrations of LDL are employed to support lymphocyte proliferation. Lymphocytes from patients heterozygous for LDL receptor abnormalities can be distinguished from normal lymphocytes since the former require twice the concentration of LDL for proliferation. By contrast, in hyperlipidemia not caused by FH, lymphocyte LDL receptor activity is normal, indicating that plasma cholesterol levels do not account for abnormalities in LDL receptor function assayed in this way. Therapy with cholesterol-lowering drugs, however, can alter lymphocyte LDL receptor activity in patients with heterozygous FH. Patients with heterozygous FH respond to therapy with mevinolin and a bile-acid-binding resin by lowering plasma cholesterol levels. In some patients, treatment with cholesterol-lowering plasma cholesterol levels. In some patients, treatment with cholesterol-lowering plasma cholesterol agents is also associated with normalization of functional lymphocyte LDL receptor activity, thereby providing direct evidence that therapy can alter LDL receptor expression.(ABSTRACT TRUNCATED AT 250 WORDS)

UI	MeSH Term	Description	Entries
D008148	Lovastatin	A fungal metabolite isolated from cultures of Aspergillus terreus. The compound is a potent anticholesteremic agent. It inhibits 3-hydroxy-3-methylglutaryl coenzyme A reductase (HYDROXYMETHYLGLUTARYL COA REDUCTASES), which is the rate-limiting enzyme in cholesterol biosynthesis. It also stimulates the production of low-density lipoprotein receptors in the liver.	Lovastatin, 1 alpha-Isomer,Mevinolin,6-Methylcompactin,Lovastatin, (1 alpha(S*))-Isomer,MK-803,Mevacor,Monacolin K,1 alpha-Isomer Lovastatin,6 Methylcompactin,Lovastatin, 1 alpha Isomer,MK 803,MK803,alpha-Isomer Lovastatin, 1
D008213	Lymphocyte Activation	Morphologic alteration of small B LYMPHOCYTES or T LYMPHOCYTES in culture into large blast-like cells able to synthesize DNA and RNA and to divide mitotically. It is induced by INTERLEUKINS; MITOGENS such as PHYTOHEMAGGLUTININS, and by specific ANTIGENS. It may also occur in vivo as in GRAFT REJECTION.	Blast Transformation,Blastogenesis,Lymphoblast Transformation,Lymphocyte Stimulation,Lymphocyte Transformation,Transformation, Blast,Transformation, Lymphoblast,Transformation, Lymphocyte,Activation, Lymphocyte,Stimulation, Lymphocyte
D008214	Lymphocytes	White blood cells formed in the body's lymphoid tissue. The nucleus is round or ovoid with coarse, irregularly clumped chromatin while the cytoplasm is typically pale blue with azurophilic (if any) granules. Most lymphocytes can be classified as either T or B (with subpopulations of each), or NATURAL KILLER CELLS.	Lymphoid Cells,Cell, Lymphoid,Cells, Lymphoid,Lymphocyte,Lymphoid Cell
D011973	Receptors, LDL	Receptors on the plasma membrane of nonhepatic cells that specifically bind LDL. The receptors are localized in specialized regions called coated pits. Hypercholesteremia is caused by an allelic genetic defect of three types: 1, receptors do not bind to LDL; 2, there is reduced binding of LDL; and 3, there is normal binding but no internalization of LDL. In consequence, entry of cholesterol esters into the cell is impaired and the intracellular feedback by cholesterol on 3-hydroxy-3-methylglutaryl CoA reductase is lacking.	LDL Receptors,Lipoprotein LDL Receptors,Receptors, Low Density Lipoprotein,LDL Receptor,LDL Receptors, Lipoprotein,Low Density Lipoprotein Receptor,Low Density Lipoprotein Receptors,Receptors, Lipoprotein, LDL,Receptor, LDL,Receptors, Lipoprotein LDL
D002453	Cell Cycle	The complex series of phenomena, occurring between the end of one CELL DIVISION and the end of the next, by which cellular material is duplicated and then divided between two daughter cells. The cell cycle includes INTERPHASE, which includes G0 PHASE; G1 PHASE; S PHASE; and G2 PHASE, and CELL DIVISION PHASE.	Cell Division Cycle,Cell Cycles,Cell Division Cycles,Cycle, Cell,Cycle, Cell Division,Cycles, Cell,Cycles, Cell Division,Division Cycle, Cell,Division Cycles, Cell
D002784	Cholesterol	The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.	Epicholesterol
D006579	Heterozygote	An individual having different alleles at one or more loci regarding a specific character.	Carriers, Genetic,Genetic Carriers,Carrier, Genetic,Genetic Carrier,Heterozygotes
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D006938	Hyperlipoproteinemia Type II	A group of familial disorders characterized by elevated circulating cholesterol contained in either LOW-DENSITY LIPOPROTEINS alone or also in VERY-LOW-DENSITY LIPOPROTEINS (pre-beta lipoproteins).	Hyperbetalipoproteinemia,Hypercholesterolemia, Essential,Hypercholesterolemia, Familial,Apolipoprotein B-100, Familial Defective,Apolipoprotein B-100, Familial Ligand-Defective,Familial Combined Hyperlipoproteinemia,Hyper-Low Density Lipoproteinemia,Hyper-Low-Density-Lipoproteinemia,Hyper-beta-Lipoproteinemia,Hypercholesterolemia, Autosomal Dominant,Hypercholesterolemia, Autosomal Dominant, Type B,Hypercholesterolemic Xanthomatosis, Familial,Hyperlipoproteinemia Type 2,Hyperlipoproteinemia Type IIa,Hyperlipoproteinemia Type IIb,Hyperlipoproteinemia, Type II,Hyperlipoproteinemia, Type IIa,LDL Receptor Disorder,Apolipoprotein B 100, Familial Defective,Apolipoprotein B 100, Familial Ligand Defective,Autosomal Dominant Hypercholesterolemia,Autosomal Dominant Hypercholesterolemias,Combined Hyperlipoproteinemia, Familial,Combined Hyperlipoproteinemias, Familial,Density Lipoproteinemia, Hyper-Low,Density Lipoproteinemias, Hyper-Low,Disorder, LDL Receptor,Disorders, LDL Receptor,Dominant Hypercholesterolemia, Autosomal,Dominant Hypercholesterolemias, Autosomal,Essential Hypercholesterolemia,Essential Hypercholesterolemias,Familial Combined Hyperlipoproteinemias,Familial Hypercholesterolemia,Familial Hypercholesterolemias,Familial Hypercholesterolemic Xanthomatoses,Familial Hypercholesterolemic Xanthomatosis,Hyper Low Density Lipoproteinemia,Hyper beta Lipoproteinemia,Hyper-Low Density Lipoproteinemias,Hyper-Low-Density-Lipoproteinemias,Hyper-beta-Lipoproteinemias,Hyperbetalipoproteinemias,Hypercholesterolemias, Autosomal Dominant,Hypercholesterolemias, Essential,Hypercholesterolemias, Familial,Hypercholesterolemic Xanthomatoses, Familial,Hyperlipoproteinemia Type 2s,Hyperlipoproteinemia Type IIas,Hyperlipoproteinemia Type IIbs,Hyperlipoproteinemia Type IIs,Hyperlipoproteinemia, Familial Combined,Hyperlipoproteinemias, Familial Combined,Hyperlipoproteinemias, Type II,Hyperlipoproteinemias, Type IIa,LDL Receptor Disorders,Lipoproteinemia, Hyper-Low Density,Lipoproteinemias, Hyper-Low Density,Receptor Disorder, LDL,Receptor Disorders, LDL,Type 2, Hyperlipoproteinemia,Type II Hyperlipoproteinemia,Type II Hyperlipoproteinemias,Type IIa Hyperlipoproteinemia,Type IIa Hyperlipoproteinemias,Xanthomatoses, Familial Hypercholesterolemic,Xanthomatosis, Familial Hypercholesterolemic