Medium and culture of embryonic stem cells

Abstract

Previous methods for culturing human embryonic stem cells have required either fibroblast feeder cells or a medium which has been exposed to fibroblast feeder cells in order to maintain the stem cells in an undifferentiated state. It has now been found that if high levels of fibroblast growth factor, gamma amino butyric acid, pipecholic acid, lithium and transforming growth factor beta are added to the medium in which the stem cells are cultured, the stem cells will remain undifferentiated indefinitely through multiple passages, even without feeder cells or conditioned medium.

1 . A method for culturing human stem cells in an undifferentiated state on a matrix without the need for feeder cells or conditioned medium, the method comprising the step of
 culturing the human stem cells in a medium including salts, vitamins, amino acids, glucose, a fibroblast growth factor, gamma amino butyric acid, pipecholic acid, lithium and transforming growth factor beta, in sufficient amounts to maintain the human stem cells in an undifferentiated state through multiple successive culture passages.   
   
   
       2 . The method of  claim 1  wherein the medium includes the fibroblast growth factor in a concentration of at least 40 μg/ml. 
   
   
       3 . The method of  claim 1  wherein the medium also comprises transferrin and insulin. 
   
   
       4 . The method of  claim 1  wherein the human stem cells are embryonic stem cells. 
   
   
       5 . In a method of culturing human embryonic stem cells on a matrix and in a medium including salts, vitamins, amino acids, and a fibroblast growth factor, the improvement comprising adding to the medium an amount of gamma amino butyric acid, pipecholic acid, lithium and transforming growth factor beta in an amount sufficient to maintain the cells in an undifferentiated state through multiple successive culture passages. 
   
   
       6 . An in vitro cell culture comprising in a culture vessel:
 human stem cells;   a matrix on which stem cells can grow; and   a culture medium, the culture medium comprising salts, vitamins, amino acids, glucose, a fibroblast growth factor, gamma amino butyric acid, pipecholic acid, lithium and transforming growth factor beta in sufficient amounts to maintain the human stem cells in an undifferentiated state through multiple culture passages, the medium being free of feeder cells and never having been exposed to feeder cells.   
   
   
       7 . A cell culture as claimed in  claim 6  wherein the medium includes the fibroblast growth factor in a concentration of at least 40 ng/ml. 
   
   
       8 . A cell culture as claimed in  claim 6  wherein the medium included the fibroblast growth factor in a concentration of at least 100 ng/ml. 
   
   
       9 . A cell culture as claimed in  claim 6  wherein the medium further comprises proteins selected from the group consisting of albumin, insulin and transferrin. 
   
   
       10 . A cell culture as claimed in  claim 6  wherein the proteins are human. 
   
   
       11 . A cell culture as claimed in  claim 10  wherein the insulin and transferrin are recombinant proteins. 
   
   
       12 . A cell culture as claimed in  claim 6  wherein the stem cells are human embryonic stem cells. 
   
   
       13 . A culture of human embryonic stem cells comprising undifferentiated human stem cells, a matrix and a culture medium, the culture free of feeder cells or medium exposed to feeder cells, the medium also free of products from non-human animals, the human embryonic stem cells proliferating in an undifferentiated state and being at least 90% positive for the transcription factor Oct4 through prolonged culture. 
   
   
       14 . A culture of human embryonic stem cells as claimed in  claim 13  wherein the cells do not exhibit the sialic acid residue Neu5Gc. 
   
   
       15 . A medium for culturing stem cells, the medium comprising salts, vitamins, amino acids, glucose, a fibroblast growth factor, gamma amino butyric acid, pipecholic acid, lithium and transforming growth factor beta in sufficient amounts to maintain stem cells grown in the medium in an undifferentiated state through multiple culture passages. 
   
   
       16 . The medium of  claim 15 , wherein the medium further comprises proteins selected from the group consisting of albumin, insulin and transferrin.