Flowable tissue matrices

Abstract

Disclosed herein are flowable tissue matrix compositions comprising small pieces of partially or completely decellularized tissue suspended in a gelatinized tissue or gelatin gel comprising partially or completely decellularized tissue or synthetic gelatin. The flowable tissue matrix compositions can contain factors that promote or enhance native cell migration, proliferation, and/or revascularization after implantation into a subject. Also disclosed are methods of making and using the flowable tissue matrix compositions. The compositions can be implanted into a tissue in need of repair, regeneration, healing, treatment, and/or alteration, and can promote or enhance native cell migration, proliferation, and/or revascularization.

What is claimed is: 
     
         1 . A flowable tissue matrix composition, comprising a first component of small pieces of partially or completely decellularized tissue, wherein a majority of the small pieces of partially or completely decellularized tissue have a length, a width, and a height ranging from about 1.0 mm to 5.0 mm and a surface area to volume ratio of less than about 6 mm 2 /mm 3 , and wherein the small pieces of partially or completely decellularized tissue are suspended in a second component comprising less than about 20% of the composition on a volume/volume (v/v) basis. 
     
     
         2 . The composition of  claim 1 , wherein the small pieces of partially or completely decellularized tissue in the composition have an increased resistance to degradation or resorption as measured using a type I collagenase digestion assay, as compared to a homogenized acellular tissue, while also retaining the ability to flow into and mold to the shape of an implant site. 
     
     
         3 . The composition of  claim 1 , wherein the majority of the length, width, and height of the small pieces of partially or completely decellularized tissue ranges from about 2.0 mm to 4.0 mm. 
     
     
         4 . The composition of  claim 1 , wherein a majority of the small pieces of partially or completely decellularized tissue in the composition have a surface area to volume ratio of greater than about 1.5 mm 2 /mm 3  and less than about 6 mm 2 /mm 3 . 
     
     
         5 . The composition of  claim 1 , wherein a majority of the small pieces of partially or completely decellularized tissue in the composition have a surface area to volume ratio of less than about 4.5 mm 2 /mm 3  and greater than about 2.0 mm 2 /mm 3 . 
     
     
         6 . The composition of  claim 1 , wherein the second component is a gelatin gel. 
     
     
         7 . The composition of  claim 6 , wherein the gelatin gel is crosslinked. 
     
     
         8 . The composition of  claim 1 , wherein the flowable tissue matrix composition lacks alpha-galactose moieties. 
     
     
         9 . The composition of  claim 1 , further comprising one or more viable cells. 
     
     
         10 . The composition of  claim 9 , wherein the one or more viable cells are mammalian cells. 
     
     
         11 . The composition of  claim 9 , wherein the one or more viable cells are stem cells. 
     
     
         12 . The composition of  claim 1 , further comprising at least one additional factor selected from a group consisting of an anti-inflammatory agent, an analgesic, a cell growth factor, an angiogenic factor, a differentiation factor, a cytokine, a hormone, and a chemokine. 
     
     
         13 . The composition of  claim 12 , wherein the at least one additional factor is encoded by a nucleic acid sequence contained within an expression vector. 
     
     
         14 . The composition of  claim 13 , wherein the expression vector is contained within one or more viable cells. 
     
     
         15 . The composition of  claim 1 , wherein the flowable tissue matrix composition has been subjected to a sterilization process. 
     
     
         16 . The composition of  claim 1 , wherein the second component comprises a gelatinized tissue that has been heated to at least about 50° C. and then allowed to cool. 
     
     
         17 . The composition of  claim 16 , wherein the gelatinized tissue comprises homogenized acellular or partially decellularized tissue in an aqueous solution at a concentration of about 0.1-10.0% weight/volume (w/v). 
     
     
         18 . A method of making a flowable tissue matrix composition, comprising:
 preparing a first component by:
 selecting a tissue containing an extracellular matrix; 
 partially or completely decellularizing the tissue to produce a partially or completely decellularized tissue; and 
 processing the partially or completely decellularized tissue to produce small pieces, wherein a majority of the small pieces have a length, a width, and a height ranging from about 1.0 mm to 5.0 mm and a surface area to volume ratio of less than about 6 mm 2 /mm 3 ; 
   preparing a second component comprising a carrier; and   combining the small pieces of partially or completely decellularized tissue with the carrier, wherein the carrier comprises less than about 20% of the composition on a volume/volume (v/v) basis.   
     
     
         19 . The method of  claim 18 , further comprising contacting the first partially or completely decellularized tissue with one or more viable cells. 
     
     
         20 . The method of  claim 19 , wherein the one or more viable cells are mammalian cells. 
     
     
         21 . The method of  claim 19 , wherein the one or more viable cells are stem cells. 
     
     
         22 . The method of  claim 18 , further comprising adding at least one additional factor selected from a group consisting of an anti-inflammatory agent, an analgesic, a cell growth factor, an angiogenic factor, a differentiation factor, a cytokine, a hormone, and a chemokine. 
     
     
         23 . The method of  claim 22 , wherein the at least one additional factor is encoded by a nucleic acid sequence contained within an expression vector. 
     
     
         24 . The method of  claim 23 , wherein the expression vector is contained within one or more viable cells. 
     
     
         25 . The method of  claim 18 , wherein the majority of the pieces are cut to have a length, width, and height ranging from about 2.0 mm to 4.0 mm. 
     
     
         26 . The method of  claim 18 , wherein a majority of the small pieces of partially or completely decellularized tissue in the composition have a surface area to volume ratio of greater than about 1.5 mm 2 /mm 3  and less than about 6 mm 2 /mm 3 . 
     
     
         27 . The method of  claim 18 , wherein a majority of the small pieces of partially or completely decellularized tissue in the composition have a surface area to volume ratio of less than about 4.5 mm 2 /mm 3  and greater than about 2.0 mm 2 /mm 3 . 
     
     
         28 . The method of  claim 18 , wherein preparing the second component comprises:
 gelatinizing a partially or completely decellularized tissue;   suspending the gelatinized partially or completely decellularized tissue in a solution containing one or more Lewis bases; and   homogenizing the tissue.   
     
     
         29 . The method of  claim 28 , wherein the one or more Lewis bases comprise at least one of sodium carbonate, sodium citrate, and sodium acetate. 
     
     
         30 . The method of  claim 18 , wherein the second component comprises a gelatin gel. 
     
     
         31 . The method of  claim 30 , wherein the gelatin gel is cross-linked by contacting the gel with one or more cross-linking agents. 
     
     
         32 . The method of  claim 31 , wherein the cross-linking agent is 1, 2, 3, 4, 8-pentagailoyi glucose (PGG), glutaraldehyde, or genipin. 
     
     
         33 . The method of  claim 30 , wherein preparing the gelatin gel comprises:
 placing a gelatinized tissue or a synthetic gelatin material in a hydrating solution;   heating the gelatinized tissue or synthetic gelatin material to at least about 50° C.; and   allowing the gelatinized tissue or synthetic gelatin material to cool.   
     
     
         34 . The method of  claim 33 , wherein the hydrating solution is distilled water, phosphate buffered saline, or a biocompatible saline solution. 
     
     
         35 . The method of  claim 33 , wherein the gelatinized tissue comprises homogenized acellular or partially decellularized tissue in an aqueous solution at a concentration of about 0.1-10.0% weight/volume (w/v). 
     
     
         36 . The method of  claim 18 , further comprising sterilizing the flowable tissue matrix composition.