Use of a Hydrogel for the Culture of Chondrocytes

Abstract

The invention relates to the use of a silanised hydroxypropylmethylcellulose (HPMC) or silanised hydroxyethylcellulose (HEC) hydrogel, self-crosslinking as a function of pH, for the three-dimensional ex vivo culture of chondrocytes.

1 . Use of a silanized hydroxyethylcellulose (HEC) or silanized hydroxypropylmethylcellulose (HPMC) hydrogel, which self-crosslinks as a function of pH, for three-dimensional ex vivo culture of chondrocytes.  
     
     
         2 . The use as claimed in  claim 1 , wherein the hydrogel may be obtained by the reaction of HEC of HPMC with a compound of formula (I):  
         XSi(OZ) 3   (1)  
       wherein X represents a halogen atom or a hydrocarbon group having an epoxy function, in particular C 2-20 , and Z is selected from among a hydrogen atom, an alkali metal and an alkyl group, in particular C 1-5 .  
     
     
         3 . The use as claimed in  claim 1 , wherein the HEC or the HPMC carries silanolate side groups or alkali metal or ammonium silanolate precursors representing from 0.5 to 5% of the total dry weight of the HEC or the HPMC.  
     
     
         4 . The use as claimed in  claim 1 , wherein the hydrogen consists of a polymer of the simplified formula:  
       
         
           
           
               
               
           
         
       
     
     
         5 . An ex vivo process for the preparation of a complex of cells integrated in a hydrogel, the complex being intended to be injected into a cartilaginous site, wherein said process includes the ex vivo mixing of chondrocytes with a silanized hydroxyethylcellulose (HEC) or silanized hydroxypropylmethylcellulose (HPMC) hydrogel, crosslinking as a function of pH, in a biological buffer at an appropriate pH for the crosslinking of the hydrogel, under appropriate conditions and for an appropriate period for the integration and the three-dimensional culture of the chondrocytes in the hydrogel.  
     
     
         6 . An ex vivo process for the preparation of a complex of cells integrated in a hydrogel, the complex being intended to be injected into a cartilaginous site, wherein said process includes the ex vivo mixing of undifferentiated cells capable of chondrogenic differentiation with a silanized hydroxyethylcellulose (HEC) or silanized hydroxypropylmethylcellulose (HPMC) hydrogel, self-crosslinking as a function of pH, in a biological buffer having an appropriate pH for the crosslinking of the hydrogel, under appropriate conditions and for an appropriate period for the integration and the three-dimensional culture of the chondrocytes derived from the differentiation of said undifferentiated cells, in the hydrogel.  
     
     
         7 . The process as claimed in  claim 5 , including the following ex vivo steps: 
 monolayer amplification of chondrocytes on a solid support;    harvesting of the amplified chondrocytes, dedifferentiated through the monolayer amplification thereof;    mixing of the dedifferentiated amplified chondrocytes with the hydrogel in a biological buffer at an appropriate pH for the crosslinking of the hydrogel, resulting in the integration of the chondrocytes within the hydrogel and in the redifferentiation thereof.    
     
     
         8 . The process as claimed in  claim 5 , wherein the hydrogel may be obtained by the reaction of HEC or HPMC with a compound of formula (1):  
         XSi(OZ) 3   (1)  
       wherein X represents a halogen atom or a hydrocarbon group having an epoxy function, in particular C 2-20 , and Z is selected from among a hydrogen atom, an alkali metal and an alkyl group, in particular C 1-5 .  
     
     
         9 . The process as claimed in  claim 5 , wherein the HEC or the HPMC carries silanolate side groups or alkali metal or ammonium silanolate precursors representing from 0.5 to 5% of the total dry weight of the HEC or the HPMC.  
     
     
         10 . The process as claimed in  claim 5 , wherein the hydrogel consists of a polymer of the simplified formula:  
       
         
           
           
               
               
           
         
       
     
     
         11 . The process as claimed in  claim 6 , wherein the hydrogel may be obtained by the reaction of HEC or HPMC with a compound of formula (1):  
         XSi(OZ) 3   (1)  
       wherein X represents a halogen atom or a hydrocarbon group having an epoxy function, in particular C 2-20 , and Z is selected from among a hydrogen atom, an alkali metal and an alkyl group, in particular C 1-5 .  
     
     
         12 . The process as claimed in  claim 6 , wherein the HEC or the HPMC carries silanolate side groups or alkali metal or ammonium silanolate precursors representing from 0.5 to 5% of the total dry weight of the HEC or the HPMC.  
     
     
         13 . The process as claimed in  claim 6 , wherein the hydrogel consists of a polymer of the simplified formula: