Drug testing system with bio-artificial liver

Abstract

A drug testing system using a liver-slice culture apparatus. The apparatus has a chamber with plasma and gas valves, animal liver slices being positioned securely in the chamber so as to maximize the surface area of liver slices exposed to the culture medium. Plasma is supplied to the chamber so that it rises to contact the liver slices, and is alternately removed from contacting the liver slices. Gas is supplied to the top of the chamber. The system also includes a reservoir for containing media entering and exiting the chamber. Methods are provided for assessing the toxicity of a drug or drug candidate.

1 . A system for testing a potential drug candidate for toxicity, said system comprising: 
 a liver-slice culture apparatus, the culture apparatus comprising: 
 a chamber having a medium inlet and a gas valve;  
 a plurality of animal liver slices positioned securely within said chamber so as to maximize the surface area of the liver slices exposed to a medium; and  
 means for selectively supplying and removing a medium in the chamber so that the medium in the chamber comes into contact with the liver slices, and is removed from contact with the liver slices; and  
   a reservoir for containing the medium as it enters and exits the chamber, said animal liver slices being cultured in an environment of an oxygenated gas under the supply of the medium at regular intervals so that said slices are exposed alternatively to the medium and to the gas;    wherein when the liver slices are exposed to the potential drug candidate the toxicity of the potential drug candidate can be determined by observing the effectiveness of the liver slices to metabolize a compound in the presence of the potential drug candidate.    
     
     
         2 . The system of  claim 1 , wherein a mesh at least partially surrounds said animal liver slices so as to form a space and to retain said slices within said space, said mesh being approximately vertical in the chamber.  
     
     
         3 . The system of  claim 2 , wherein two meshes at least partially surround said liver slices.  
     
     
         4 . The system of  claim 1 , wherein the liver slices have a thickness in the range of about 10 μm to about 2,000 μm.  
     
     
         5 . The system of  claim 1 , wherein the liver slices have a thickness in the range of about 100 μm to about 500 μm.  
     
     
         6 . The system of  claim 1 , further comprising a means for introducing a gas to the gas valve.  
     
     
         7 . The system of  claim 6 , wherein the gas is a mixture of oxygen and carbon dioxide.  
     
     
         8 . The system of  claim 7 , wherein the gas-to-plasma exposure time ratio to the animal liver slices is about 1:2 to about 1:4.  
     
     
         9 . The system of  claim 7 , wherein the gas-to-plasma exposure time ratio to the animal liver slices is about 1:3.  
     
     
         10 . The system of  claim 1 , further comprising an immunological filter inserted in the gas valve.  
     
     
         11 . The system of  claim 1 , wherein the chamber is sealable.  
     
     
         12 . The system of  claim 11 , wherein the chamber is thermoregulated.  
     
     
         13 . The system of  claim 1 , wherein the compound is selected from the group consisting of ammonia and lidocaine.  
     
     
         14 . A method for evaluating the toxicity of a drug, said method comprising: 
 supplying a culture medium;    contacting the culture medium with animal liver slices, the animal liver slices being positioned securely in a chamber so as to maximize the surface area of liver slices exposed to the culture medium, wherein the chamber has a plasma inlet and a gas valve, means for selectively supplying and removing plasma in the chamber so that the plasma in the chamber comes into contact with the liver slices, and is alternately removed from contact with the liver slices, means for supplying a gas to the chamber, a reservoir for containing plasma as it enters and exits the chamber, the method further comprising: 
 contacting the liver slices with a gas mixture of oxygen and carbon dioxide;  
 exposing the liver slices alternatively to plasma and the gas mixture of oxygen and carbon dioxide gas; and  
 exposing the liver slices to the drug to be tested;  
   wherein when the liver slices are exposed to the drug the toxicity of the drug can be determined by observing the effectiveness of the liver slices to metabolize a compound in the presence of the drug.    
     
     
         15 . The method of  claim 14 , wherein a mesh at least partially surrounds said animal liver slices so as to form a space and to retain said slices within said space, said mesh being positioned approximately vertical in the chamber.  
     
     
         16 . The method of  claim 15 , wherein the compound is selected from the group consisting of ammonia and lidocaine.