Nucleic acid constructs, cells transformed therewith and methods utilizing same for inducing liver regeneration and alleviation of portal hypertension

Abstract

A method of inducing liver regeneration in a damaged liver tissue region of an individual is provided. The method including the step of providing at least two distinct growth factors to the damaged liver tissue region of the individual, at least one of the at least two distinct growth factors being an angiogenic factor.

What is claimed is:  
     
         1 . A nucleic acid expression construct comprising: 
 (a) a first polynucleotide segment encoding a first growth factor; and    (b) a second polynucleotide segment encoding a second growth factor, at least one of said first and said second growth factors being an angiogenic factor.    
     
     
         2 . The nucleic acid expression construct of  claim 1 , further comprising at least one promoter sequence being for directing the expression of at least one of said first and said second polynucleotide segments.  
     
     
         3 . The nucleic acid construct of  claim 2 , wherein said first polynucleotide segment is transcriptionally linked to said second polynucleotide segment whereas said first and said second polynucleotide segment are under the transcriptional control of a single promoter sequence of said at least one promoter sequence.  
     
     
         4 . The nucleic acid construct of  claim 3 , further comprising a linker sequence being interposed between said first and said second polynucleotide segments.  
     
     
         5 . The nucleic acid construct of  claim 1 , wherein said linker sequence is selected from the group consisting of an IRES encoding sequence and a protease cleavage recognition site encoding sequence.  
     
     
         6 . The nucleic acid expression construct of  claim 2 , wherein said at least one promoter is functional in eukaryotic cells.  
     
     
         7 . The nucleic acid expression construct of  claim 2 , wherein said at least one promoter is selected from the group consisting of a constitutive promoter, an inducible promoter and a tissue specific promoter.  
     
     
         8 . The nucleic acid expression construct of  claim 1 , further comprising: 
 (c) a first promoter sequence being for directing the expression of said first polynucleotide segment; and    (d) a second promoter sequence being for directing the expression of said second polynucleotide segment.    
     
     
         9 . The nucleic acid expression construct of  claim 8 , wherein said first promoter and said second promoter are each independently selected from the group consisting of a constitutive promoter, an inducible promoter and a tissue specific promoter.  
     
     
         10 . The nucleic acid construct of  claim 1 , wherein said first and said second growth factors are each independently selected from the group consisting of vascular endothelial growth factor (VEGF), a hepatocyte growth factor (HGF), a platelet derived growth factor (PDGF), a fibroblast growth factor 1 (FGF 1) and a fibroblast growth factor 2 (FGF 2).  
     
     
         11 . A genetically transformed cell comprising the nucleic acid expression construct of  claim 1 .  
     
     
         12 . The transformed cell of  claim 11 , wherein the cell is selected from the group consisting of an hepatocyte cell, an endothelial cell, and a progenitor cell.  
     
     
         13 . The transformed cell of  claim 17 , wherein said endothelial cell is derived from a source selected from the group consisting of a segment of a liver, a segment of a vein, bone marrow progenitor cells, peripheral blood stem cells, circulating endothelial cells and embryonic stem cells.  
     
     
         14 . The transformed cell of  claim 11 , wherein the cell is derived from a source selected from the group consisting of a human donor and an animal source.  
     
     
         15 . A nucleic acid expression construct system comprising: 
 (a) a first nucleic acid expression construct including a first polynucleotide segment encoding first growth factor; and    (b) a second nucleic acid expression construct including a second polynucleotide segment encoding a second growth factor, at least one of said first and said second growth factors being an angiogenic factor.    
     
     
         16 . The nucleic acid expression constructs system of  claim 15 , wherein said first and said second nucleic acid expression constructs each further include a promoter sequence being for directing expression of said first and said second polynucleotide segment.  
     
     
         17 . The nucleic acid expression constructs system of  claim 16 , wherein said promoter sequence is functional in eukaryotic cells.  
     
     
         18 . The nucleic acid expression constructs system of  claim 16 , wherein said promoter sequence is selected from the group consisting of a constitutive promoter, an inducible promoter and a tissue specific promoter.  
     
     
         19 . A population of cells transformed with at least one nucleic acid construct being capable of expressing at least two distinct growth factors, said at least two distinct growth factors including at least one angiogenic factor.  
     
     
         20 . The population of cells of  claim 19 , wherein the population of cells is stabely or transiently transformed with said at least one nucleic acid construct.  
     
     
         21 . The population of cells of  claim 19 , wherein said population of cells includes at least two cell types selected from the group consisting of hepatocytes cells, endothelial cells, and progenitor cells.  
     
     
         22 . The population of cells of  claim 21 , wherein each cell type of said at least two cell types is genetically transformed to express one specific growth factor of said at least two distinct growth factors.  
     
     
         23 . The population of cells of  claim 21 , wherein said first cell type is an hepatocyte cell and further wherein said second cell type is an endothelial cell and vice versa.  
     
     
         24 . The population of cells of  claim 21 , wherein said endothelial cell is derived from a source selected from the group consisting of venous tissue, arterial tissue, fat tissue, progenitor cells, circulating endothelial cells and bone marrow stem cells.  
     
     
         25 . The population of cells of  claim 19 , wherein expression of each growth factor of said at least two distinct growth factors is independently regulatable.  
     
     
         26 . The population of cells of  claim 19 , wherein said at least two distinct growth factors are each independently selected from the group consisting of VEGF, HGF, PDGF, FGF 1 and FGF 2.  
     
     
         27 . A method of inducing liver regeneration in a damaged liver tissue region of an individual, the method comprising the step of providing at least two distinct growth factors to the damaged liver tissue region of the individual, at least one of said at least two distinct growth factors being an angiogenic factor.  
     
     
         28 . The method of  claim 27 , wherein said step of providing said at least two distinct growth factors to the damaged liver tissue region of the individual is effected by administering to the individual at least one nucleic acid construct being capable of expressing said at least two distinct growth factors.  
     
     
         29 . The method of  claim 27 , wherein said step of providing said at least two distinct growth factors to the damaged liver tissue region of the individual is effected by administering to the damaged liver tissue region of the individual a population of cells being capable of expressing and optionally secreting said at least two distinct growth factors.  
     
     
         30 . The method of  claim 27 , wherein the method is utilized for treating or alleviating liver damage in an individual.  
     
     
         31 . The method of  claim 27 , wherein the method is utilized for treating or preventing portal hypertension.  
     
     
         32 . The method of  claim 27 , wherein said individual is human being.  
     
     
         31 . The method of  claim 27 , wherein said population of cells includes at least two cell types.  
     
     
         32 . The method of  claim 31 , wherein said at least two cell types are derived from the individual.  
     
     
         33 . The method of  claim 27 , wherein said at least two cell types are each independently selected from the group consisting of hepatocytes cells, endothelial cells and progenitor cells.  
     
     
         34 . The method of  claim 19 , wherein said at least two distinct growth factors are each independently selected from the group consisting of VEGF, HGF, PDGF, FGF 1 and FGF 2.  
     
     
         35 . A delivery catheter comprising: 
 (a) an elongated body having open proximal and distal ends defining a flowthrough passage therebetween, said elongated body being sized and constructed for positioning within a biological vessel; and    (b) an inflatable balloon being attached to, or forming a part of, a circumferential surface portion of said elongated body, said inflatable balloon being designed and constructed for sealing a space formed between said circumferential surface portion of said elongated body and adjacent walls of said biological vessel when inflated, thereby preventing flow back of material delivered through said flowthrough passage.    
     
     
         36 . The delivery catheter of  claim 35 , further comprising an injection port being in fluid communication with said inflatable balloon and being positioned outside the body when said elongated body is positioned within said biological vessel.  
     
     
         37 . The delivery catheter of  claim 35 , further comprising a delivery port being in fluid communication with said flowthrough passage and being positioned outside the body when said elongated body is positioned within said biological vessel.