Regulating stem cells

Abstract

A composition of matter is provided, comprising a population of cultured cells that comprises a sub-population of cells that both stain as CD31Bright and demonstrate uptake of Ac-LDL+, and secrete IL-8. A method is also provided, comprising stimulating in vitro an initiating cell population (ICP) of at least 5 million cells that have a density of less than 1.072 g/ml, wherein at least 1% of the cells of the ICP is CD34+CD45−/Dim, and at least 25% of the cells of the ICP are CD31Bright, to differentiate into a progenitor/precursor cell population (PCP). Other embodiments are also described.

1 . A composition of matter, comprising a population of cultured cells that comprises a sub-population of cells that both stain as CD31Bright and demonstrate uptake of Ac-LDL+, wherein at least 1.5% of the cells of the population have a tendency to migrate toward IL-8. 
     
     
         2 . The composition of matter according to  claim 1 , wherein the sub-population comprises at least 10% of the cells in the population. 
     
     
         3 . The composition of matter according to  claim 1 , wherein the sub-population comprises at least 25% of the cells in the population. 
     
     
         4 . The composition of matter according to  claim 1 , wherein the sub-population comprises at least 50% of the cells in the population. 
     
     
         5 . The composition of matter according to  claim 1 , wherein the sub-population secretes IL-8. 
     
     
         6 . The composition of matter according to  claim 5 , wherein the sub-population secretes at least 50 pg IL-8 per 10 6  cells/ml over a period of at least 24 hours. 
     
     
         7 . The composition of matter according to  claim 5 , wherein the sub-population secretes at least 150 pg IL-8 per 10 6  cells/ml over a period of at least 24 hours. 
     
     
         8 . The composition of matter according to  claim 5 , wherein the sub-population secretes at least 1000 pg per 10 6  cells/ml over a period of at least 24 hours. 
     
     
         9 . The composition of matter according to  claim 1 , wherein at least 1.5% of the cells of the population include a morphological feature selected from the group consisting of: a cell size larger than 20 um, an elongated cell, a spindle-shaped cell, an irregularly-shaped cell, a granulated cell, a cell including an enlarged dark nucleus, a multinuclear cell, a cell including flagella-like structures, a cell including pseudopodia, and a cell having a polygonal shape. 
     
     
         10 . The composition of matter according to  claim 1 , wherein at least 1.5% of the cells of the population comprise a feature selected from the group consisting of: CD34, CD117, CD133, Tie-2, CD34+CD133+, KDR, CD34+KDR+, CD144, von Willebrand Factor, SH2 (CD105), SH3, fibronectin, collagen type I, collagen type III, collagen type IV, ICAM type 1, ICAM type 2, VCAM1, vimentin, BMP-R IA, BMP-RII, CD44, integrin b1, aSM-actin, MUC18, CXCR8 and CXCR4. 
     
     
         11 . The composition of matter according to  claim 1 , wherein at least 1.5% of the cells of the population secrete a molecule selected from the group consisting of: IL-8, angiogenin, VEGF, MMP2, and MMP9. 
     
     
         12 . The composition of matter according to  claim 1 , wherein at least 1.5% of the cells of the population include a feature selected from the group consisting of: a tube-like structure, a tendency to form a colony, a tendency to form a cluster, and a tendency to migrate toward a chemoattractant. 
     
     
         13 . The composition of matter according to  claim 1 , wherein at least 1.5% of the cells of the population have a tendency to migrate toward a chemoattractant selected from the group consisting of: bFGF, VEGF, SCF, G-CSF, GM-CSF, and SDF-1. 
     
     
         14 - 159 . (canceled)