Xenograft heart valves

Abstract

The invention provides an article of manufacture comprising a substantially non-immunogenic heart valve xenograft for implantation into humans. The invention further provides methods for preparing a heart valve xenograft by removing at least a portion of a soft tissue from a non-human animal to provide a xenograft; washing the xenograft in saline and alcohol; subjecting the xenograft to cellular disruption treatment; treating the xenograft with crosslinking agents, and digesting the xenograft with a proteoglycan-depleting factor and/or glycosidase. The invention also provides an article of manufacture produced by the above-identified method of the invention. The invention further provides a heart valve xenograft for implantation into a human including a portion of a heart valve from a non-human animal, wherein the portion has extracellular components and substantially only dead cells. The extracellular components have reduced proteoglycan molecules. Each of the xenografts of the invention are substantially non-immunogenic and have substantially the same mechanical properties as a corresponding native heart valve.

What is claimed is:  
     
         1 . A method of preparing a xenograft heart valve for implantation into a human, which comprises 
 a. removing at least a portion of a heart valve from a non-human animal to provide a xenograft;    b. washing the xenograft in water and alcohol;    c. subjecting the xenograft to a cellular disruption treatment; and    d. treating the xenograft with a glycosidase to remove a plurality of first surface carbohydrate moieties,    whereby the xenograft is substantially non-immunogenic and has substantially the same mechanical properties as the native heart valve.    
     
     
         2 . A method according to  claim 1 , wherein the glycosidase is a galactosidase.  
     
     
         3 . A method according to  claim 2 , wherein the galactosidase is an α-galactosidase.  
     
     
         4 . A method according to  claim 1 , further comprising the step of depleting substantially a plurality of proteoglycans from the xenograft.  
     
     
         5 . A method according to  claim 4 , wherein the depleting step comprises digesting the xenograft with at least one proteoglycan-depleting factor selected from the group consisting of chondroitinase ABC, hyaluronidase, chondroitin AC II lyase, keratanase, trypsin and fibronectin fragment.  
     
     
         6 . A method according to  claim 1   after step c, piercing the xenograft.    
     
     
         7 . A method according to  claim 1  further comprising the step of 
 after step c, treating the xenograft with at least one enzyme.  
 
     
     
         8 . A method according to  claim 7 , wherein the enzyme is selected from the group consisting of ficin and trypsin.  
     
     
         9 . A method according to  claim 1  further comprising the step of after step c, treating the xenograft with one or more agents selected from the group consisting of anticalcification agents, antithrombotic agents, antibiotics, and growth factors.  
     
     
         10 . A method according to  claim 1  further comprising the step of 
 after step c, sterilizing the xenograft.  
 
     
     
         11 . A method according to  claim 10 , wherein the sterilizing step comprises sterilizing the xenograft with one or more agents selected from the group consisting of ethylene oxide, and propylene oxide.  
     
     
         12 . A method according to  claim 1 , further comprising the step of: 
 after step c, treating the xenograft with at least one crosslinking agent.    
     
     
         13 . A method according to  claim 12 , wherein the crosslinking agent is selected from the group consisting of aldehydes, aromatic diamines, carbodiimides, and diisocyanates.  
     
     
         14 . A method according to  claim 13  wherein at least one crosslinking agent is glutaraldehyde.  
     
     
         15 . A method according to  claim 14  wherein the xenograft is crosslinked using a solution containing about 0.01 percent to about 5 percent glutaraldehyde.  
     
     
         16 . A method according to  claim 4 , further comprising the step of: 
 after step c, treating the xenograft with at least one crosslinking agent.    
     
     
         17 . A method according to  claim 16 , wherein the crosslinking agent is selected from the group consisting of aldehydes, aromatic diamines, carbodiimides, and diisocyanates.  
     
     
         18 . A method according to  claim 17  wherein at least one crosslinking agent is glutaraldehyde.  
     
     
         19 . A method according to  claim 18  wherein the xenograft is crosslinked using a solution containing about 0.01 percent to about 5 percent glutaraldehyde.  
     
     
         20 . A method according to  claim 1  further comprising the step of: 
 after step c, treating the xenograft with polyethylene glycol.  
 
     
     
         21 . A method according to  claim 1  further comprising the step of 
 after step c, exposing the xenograft to a crosslinking agent in a vapor form.  
 
     
     
         22 . A method according to  claim 1 , wherein the cellular disruption treatment comprises freeze/thaw cycling.  
     
     
         23 . A method according to  claim 1 , wherein the cellular disruption treatment comprises exposure to gamma radiation.  
     
     
         24 . An article of manufacture comprising a substantially non-immunogenic, heart valve xenograft for implantation into a human, produced by 
 a. removing at least a portion of a heart valve from a non-human animal to provide a xenograft;    b. washing the xenograft in water and alcohol;    c. subjecting the xenograft to a cellular disruption treatment; and    d. treating the xenograft with a glycosidase to remove a plurality of first surface carbohydrate moieties, whereby the xenograft is substantially non- immunogenic and has substantially the same mechanical properties as the native heart valve.    
     
     
         25 . The article of manufacture according to  claim 24  wherein the glycosidase is a galactosidase.  
     
     
         26 . The article of manufacture according to  claim 25 , wherein the galactosidase is an α-galactosidase.  
     
     
         27 . The article of manufacture according to  claim 24  further compising the step, after step c, of digesting the xenograft with a proteoglycan-depleting factor to remove substantially a plurality of proteoglycans from the xenograft,  
     
     
         28 . An article of manufacture according to  claim 27 , wherein the proteoglycan-depleting factor is selected from the group consisting of chondroitinase ABC, hyaluronidase, chondroitin AC II lyase, keratanase, trypsin and fibronectin fragment.  
     
     
         29 . An article of manufacture according to  claim 24 , further comprising the step, after step b, of creating a plurality of punctures into the xenograft for increasing permeability to agents and enzymes.  
     
     
         30 . An article of manufacture according to  claim 24  further comprising treating the xenograft with one or more agents selected from the group consisting of anticalcification agents, antithrombotic agents, antibiotics, and growth factors.  
     
     
         31 . An article of manufacture according to  claim 24 , further comprising sterilizing the xenograft.  
     
     
         32 . An article of manufacture according to  claim 24 , further comprising treating the xenograft with polyethylene glycol.  
     
     
         33 . An article of manufacture according to  claim 24  further comprising, after step c, treating the xenograft with a crosslinking agent.  
     
     
         34 . An article of manufacture according to  claim 33 , wherein the crosslinking agent is an aldehyde.  
     
     
         35 . An article of manufacture according to  claim 34 , wherein the aldehyde is glutaraldehyde.  
     
     
         36 . An article of manufacture according to  claim 27  further comprising, after step c, treating the xenograft with a crosslinking agent.  
     
     
         37 . An article of manufacture according to  claim 36 , wherein the crosslinking agent is selected from the group consisting of aldehydes, aromatic diamines, carbodiimides, and diisocyanates.  
     
     
         38 . An article of manufacture according to  claim 37  wherein the aldehyde is glutaraldehyde.  
     
     
         39 . An article of manufacture according to  claim 24 , further comprising the step of after step b, freezing and thawing the xenograft.  
     
     
         40 . An article of manufacture according to  claim 24 , further comprising the step of treating the xenograft with gamma-radiation.  
     
     
         41 . A heart valve xenograft for implantation into a human comprising 
 a portion of a heart valve from a non-human animal, wherein the portion includes a plurality of extracellular components, a plurality of substantially only dead cells, the extracellular components having reduced proteoglycans, and an aldehyde in an amount ranging from about 0.01 percent to about 5 percent crosslinking a plurality of proteins of the extracellular components, the dead cells and extracellular components having substantially no surface carbohydrate moieties which are susceptible to glycosidase digestion, and    whereby the portion of the heart valve is substantially non-immunogenic and has substantially the same mechanical properties as the native heart valve.    
     
     
         42 . A heart valve xenograft according to  claim 41 , wherein the extracellular components and the substantially only dead cells have substantially no surface α-galactosyl moieties.  
     
     
         43 . A heart valve xenograft according to  claim 41 , wherein the aldehyde is glutaraldehyde.  
     
     
         44 . An article of manufacture comprising a substantially non-immunogenic aldehyde-treated, glycosidase-treated xenograft formed of a soft tissue for implantation into a human, produced by the process of 
 a. removing at least a portion of the soft tissue, heart tissue or heart valve from a non-human animal to provide a xenograft;    b. washing the xenograft in water and alcohol;    c. subjecting the xenograft to a cellular disruption treatment;    d. exposing the xenograft to an aldehyde in an amount ranging from about 0.01% to about 5%; and    e. digesting the xenograft with a glycosidase to remove substantially a plurality of surface carbohydrate moieties from the xenograft    whereby the xenograft is substantially non-immunogenic and has substantially the same mechanical properties as the native soft or bone tissue.    
     
     
         45 . An article of manufacture according to  claim 44 , wherein the aldehyde is selected from the group consisting of glutaraldehyde, formaldehyde, and adipic dialdehyde.  
     
     
         46 . An article of manufacture according to  claim 45 , wherein the xenograft has a plurality of punctures for increasing permeability to agents and enzymes.  
     
     
         47 . An article of manufacture according to  claim 45  further the xenograft has been subjected to one or more agents selected from the group consisting of anticalcification agents, antithrombotic agents, antibiotics, and growth factors.  
     
     
         48 . A heart valve xenograft for implantation into a human comprising 
 a portion of a heart valve from a non-human animal, wherein the portion includes a plurality of extracellular components, a plurality of substantially only dead cells, and an aldehyde in an amount ranging from about 0.01 percent to about 5 percent cross linking a plurality of proteins of the extracellular components, the dead cells and extracellular components having substantially no surface carbohydrate moieties which are susceptible to glycosidase digestion, and    whereby the portion of the heart valve is substantially non-immunogenic and has substantially the same mechanical properties as the native heart valve.    
     
     
         49 . A heart valve xenograft for implantation into a human comprising 
 a portion of a heart valve from a non-human animal, wherein the portion includes a plurality of extracellular components, a plurality of substantially only dead cells, the dead cells and extracellular components having substantially no surface carbohydrate moieties which are susceptible to glycosidase digestion, and    whereby the portion of the heart valve is substantially non-immunogenic and has substantially the same mechanical properties as the native heart valve.