Adult Stem Cells

Embryonic Stem Cells  

Induced Pluripotent Stem Cells  

Pros

• Trans differentiate and and reprogramming of these cells is possible but is not well studied

• Thought to be less likely to be rejected if used in transplants
• Success has already been demonstrated in various clinical applications 

• Can maintain and grow for 1 year or more in culture
• Established protocols for maintenance in culture
• ESCs are pluripotent cells that can generate most cell types
• By studying ESCs, more can be learned about the process of development

 

• Abundant somatic cells of donor can be used
• Issues of histocompatibility with donor/recipient transplants can be avoided
• Very useful for drug development and developmental studies
• Information learned from the “reprogramming” process may be transferable for in vivo therapies to reprogram damaged or diseased cells/tissues 

 Cons

• Limitations on ASC ability to differentiate are still uncertain; currently thought to be multi or unipotent.
• Cannot be grown for long periods of time in culture
• Usually a very small number in each tissue making them difficult to find and purify
• Currently there is no technology available to generate large quantities of stem cells in culture



• Process to generate ESC lines is inefficient
• Unsure whether they would be rejected if used in transplants.
• Therapies using ESC avenues are largely new and much more research and testing is needed
• If used directly from the ESC undifferentiated culture prep for tissue transplants, they can cause tumors (teratomas) or cancer development  

• Methods for ensured reproducibility and maintenance, as differentiated tissues are not certain.
• Viruses are currently used to introduce embryonic genes and has been shown to cause cancers in mouse studies  

Ethical Concerns

•   No major ethical concerns have been raised 

• To acquire the inner cell mass the embryo is destroyed
• Risk to female donors being consented



•  iPS cells have the potential to become embryos if exposed to the right conditions