Methods for the culture of human embryonic stem cells on human feeder cells

Patent Number: 7,432,104

Embryonic stem cells generally require feeder cells to grow on.  Traditionally, mouse feeder layers where used, for example in the early work when human embryonic stem cells were patented.  The importance of the feeder layer is to provide the right environment for the embryonic stem cells to be capable of proliferating without spontaneously differentiating.  The problem is that feeder layers add a level of complexity if the embryonic stem cells are going to be developed for clinical use.  For example, mouse feeder layers may contain various adventitious viruses, as well as specific glycoproteins that would elicit a hyperacute anti-xenogeneic response if administered to humans.  Companies such as Geron have gotten around this issue, in part, by developing complex cytokine and extracellular matrix media which can be used for "feeder free" cultures, as described in their patent 7,413,902.

Another creative approach was taken by the inventors of the current patent.  Although the assignee is listed as BresGen, this is one of the three companies that fused to form Novocell, the company that we interviewed a while ago.  The new approach uses human cells as feeder cells instead of relying on mouse cells.  Specifically, the patent covers, intra alia, the use of bone marrow stromal cells, fetal skin fibroblasts, cytokines, and skin keloid fibroblasts in various combinations to maintain embryonic stem cells in an undifferentiated state. 

View this patent on the USPTO website.