Methods and compositions to lower plasma cholesterol levels

Abstract

A method is disclosed for determining whether a compound binds to a lipoprotein such as LDL or VLDL in a manner which will lower plasma cholesterol is provided that includes assessing the ability of the compound to form a complex with the lipoprotein, e.g., LDL or VLDL, and then determining whether the newly formed complex causes a change in the structure of apoB-100 that results in increased binding affinity to the LDL receptor. Also disclosed is a method for lowering cholesterol in a host in need thereof, including a human, is provided that includes the administration of an effective amount of a compound which binds to cholesterol-carrying lipoprotein (e.g. LDL or VLDL) in a manner that alters the three dimensional configuration of the lipoprotein and increases the binding affinity of the apoB-100 protein to the LDL receptor, including those on the surface of a hepatic cell.

1 . A method to assess whether a compound is an LDL clearance enhancing drug that includes mixing the drug with cholesterol-containing lipoprotein in vivo or in vitro; isolating the complex, and determining whether the binding of the compound to the complex causes a change in the three dimensional conformation of apoB-100 in the lipoprotein that enhances the binding affinity of the lipoprotein to the LDL receptor; wherein the LDL-clearance enhancing drug is not probucol or a mono- or di-ester of probucol, not a compound described in WO 98/09773, and not a silyl compound described in U.S. Pat. No. 5,155,250 or 5,608,095.  
     
     
         2 . The method of  claim 1 , wherein the cholesterol-containing lipoprotein is LDL.  
     
     
         3 . The method of  claim 1 , wherein the cholesterol-containing lipoprotein is VLDL.  
     
     
         4 . The method of  claim 1 , wherein the binding of the compound to the complex is determined by a sandwich ELISA.  
     
     
         5 . The method of  claim 1 , wherein the binding of the compound to the complex is determined using agarose electrophoresis.  
     
     
         6 . A method to alter the conformation of a cholesterol-containing lipoprotein comprising mixing the cholesterol-containing lipoprotein in vivo or in vitro with a compound and determining whether the binding of the compound to the complex causes a change in the three dimensional conformation of apoB-100 in the lipoprotein that enhances the binding affinity of the lipoprotein to an LDL receptor.  
     
     
         7 . A method to determine whether a high plasma cholesterol level in a host is due to a genetic alteration of the host's apoB-100 protein comprising administering a LDL clearance enhancing drug to the patient, observing a lower than normal decrease in plasma cholesterol level, and then isolating and evaluating the host's apoB-100 protein.  
     
     
         8 . A method to determine whether a high plasma cholesterol level in a host is due to a genetic alteration of the host's apoB-100 protein comprising exposing the host's apoB-100 protein to an LDL clearance enhancing drug in vitro under conditions in which the host's apoB-100 protein and the drug can form a complex, and then isolating and evaluating the change in conformation of the host's apoB-100 protein caused by any complexation.  
     
     
         9 . A method to determine if a compound causes a change in the structure of apoB-100 in a cholesterol-containing lipoprotein that would be therapeutically useful, comprising carrying out a sandwich immunoreactivity assay in which an antibody directed to an epitope on apoB-100 (known to be important to the LDL receptor binding process) as a capture antibody is laid onto a plate, the cholesterol-containing lipoprotein/test compound complex is added to the plate, and a second antibody, which can be polyclonal or monoclonal, is then used to quantify the amount of LDL complex captured.  
     
     
         10 . A method to assess a conformational change in cholesterol-containing lipoprotein caused by complexation with a test compound comprising assessing the change in the electrophorectic mobility pattern of the cholesterol-containing lipoprotein using electrophoresis.  
     
     
         11 . A method for lowering plasma cholesterol in a host comprising administering an effective amount of a compound that binds to cholesterol-carrying lipoprotein in a manner that alters the three dimensional configuration of the lipoprotein and increases the binding affinity of the apoB-100 protein to the LDL receptor; wherein the LDL-clearance enhancing drug is not probucol or a mono- or di-ester of probucol, not a compound described in WO 98/09773, and not a silyl compound described in U.S. Pat. No. 5,155,250 or 5,608,095.  
     
     
         12 . The method of  claim 11 , wherein the LDL receptor is on the surface of hepatic cells.  
     
     
         13 . The method of  claim 11 , wherein the cholesterol-carrying liproprotein is LDL.  
     
     
         14 . The method of  claim 11 , wherein the cholesterol-carrying liproprotein is VLDL.  
     
     
         15 . A method for assessing whether a compound binds to a lipoprotein in a manner which lowers plasma cholesterol comprising complexing the compound with cholesterol-containing lipoprotein, isolating the resulting complex, and determining whether the binding of the compound to the complex causes a change in the three dimensional conformation of apoB-100 in the lipoprotein that enhances the binding affinity of the lipoprotein to the LDL receptor.  
     
     
         16 . A method for lowering plasma cholesterol in a host comprising administering an effective amount of a compound that binds to cholesterol-carrying lipoprotein in a manner that alters the three dimensional configuration of the lipoprotein and increases the binding affinity of the apoB-100 protein to the LDL receptor in combination or alternation with a second drug that lowers cholesterol via a different biological pathway; wherein the LDL-clearance enhancing drug is not probucol or a mono- or di-ester of probucol, not a compound described in WO 98/09773, and not a silyl compound described in U.S. Pat. No. 5,155,250 or 5,608,095.  
     
     
         17 . The method of  claim 16 , wherein the LDL receptor is on the surface of hepatic cells.  
     
     
         18 . The method of  claim 16 , wherein the cholesterol-carrying liproprotein is LDL.  
     
     
         19 . The method of  claim 16 , wherein the cholesterol-carrying liproprotein is VLDL.  
     
     
         20 . The method of  claim 16 , wherein the second drug is selected from the group consisting of a statin, a bile acid sequestrant, nicotinic acid, probucol, a fibrate derivative, Neomycin, and cholestyramine.