There are far fewer donor organs available than there are patients who need transplants, and many people die while waiting. Donor organs also have to be closely tissue-matched, and even then the recipient's immune system may reject them, so patients take immunosuppressant drugs for life.Stem cells could solve both problems by growing organs from the patient's own cells, which carry matching antigens and so are not rejected.Scaffold method
1. A donor organ, or an artificial frame, is treated with detergents to remove all its cells, leaving a collagen scaffold with the organ's shape and blood vessel channels.
2. The scaffold is seeded with stem cells taken from the patient.
3. In a bioreactor, the cells multiply and differentiate to cover the scaffold.
4. The new organ is transplanted.
Simple hollow organs such as bladders have been grown and transplanted in this way.
Other approaches
• Organoids: small, simplified three-dimensional organs grown from stem cells in the lab. They are used mainly for research and drug testing, but may one day replace damaged tissue.
• 3D bioprinting: printing layers of cells and supporting material to build tissue.Limitations
Solid organs such as the heart, kidney and liver contain many cell types in a precise arrangement and need a full blood supply, so they are much harder to grow. Growing an organ also takes a long time, which may be too slow for an emergency.
1. A donor organ, or an artificial frame, is treated with detergents to remove all its cells, leaving a collagen scaffold with the organ's shape and blood vessel channels.
2. The scaffold is seeded with stem cells taken from the patient.
3. In a bioreactor, the cells multiply and differentiate to cover the scaffold.
4. The new organ is transplanted.
Simple hollow organs such as bladders have been grown and transplanted in this way.
Other approaches• Organoids: small, simplified three-dimensional organs grown from stem cells in the lab. They are used mainly for research and drug testing, but may one day replace damaged tissue.
• 3D bioprinting: printing layers of cells and supporting material to build tissue.Limitations
Solid organs such as the heart, kidney and liver contain many cell types in a precise arrangement and need a full blood supply, so they are much harder to grow. Growing an organ also takes a long time, which may be too slow for an emergency.