Credit: MRC Centre for Regenerative Medicine, University of Edinburgh

Edinburgh, U.K. - Scientific researchers have grown a completely functional organ from laboratory-developed cells in a living animal for the very first time. Scientists transplanted a fully functional thymus -- an important organ that supplies the body with immunity cells. Left: Specialised thymus cells were developed from an entirely distinct cell type utilizing a laboratory technique called re-programming. Right: The cells were transplanted onto a mouse kidney to create an organised and functional mini-thymus within a living creature.

The ability for researchers to grow replacement organs in the laboratory took a dramatic turn this week when scientists at the MRC Centre for Regenerative Medicine at the University of Edinburgh announced the completion of a new study. For the first time, scientists have been successful at creating a fully functional thymus gland from stem cells transplanted from a living animal, and cultivated in vitro.

Researchers focused on the thymus gland because of its proximity to the heart and its ability to produce immune cells known as T cells, which are only produced in the thymus, and yet critical for safeguarding against disease and infection. They hope, with further study, this milestone could open the path to new treatments for people with a weakened or compromised immune system.

Scientists removed cells called fibroblasts from a mouse embryo and then completely reformed them using a technique we've discussed previously, called "reprogramming," (For more information, see also, Cell Therapy Future Perspectives).

During this process, they observed the cells change shape to look like thymus cells, which were also functionally capable of producing T cells in the lab. Researchers then mixed these reprogrammed cells with other thymus cell types and then transplanted them into a mouse. Eventually, the cells formed what researchers were hoping for, a replacement organ with the same function and sophistication as a healthy, adult thymus.

This is a milestone in 21st century medicine, marking the first time scientists have created an entire living organ from cells created outside of the body. Doctors are already able to treat patients with thymus disorders with transplantation or infusions of extra immune cells shortly after birth. The issue is that both methods are restricted by a lack of donors and problems with organ rejection.

Such techniques may benefit patients in cell therapy by offering a way to match T cells to their donors. It could benefit bone marrow transplant patients, by way of speeding up how quickly the immune system rebuilds after transplant. This discovery also offers hope to those born with genetic ailments that prevent the thymus from growing properly. And since clinicians say that the thymus is the first organ to breakdown over time, many older folks can be helped to improve their quality of life.

With more time, research, and refinement in their experiments, they say that this discovery and their process of reprogramming cells could form the the foundation of a thymus transplant treatment plan for people with a weakend immune system.

Professor Clare Blackburn from the MRC Centre for Regenerative Medicine at the University of Edinburgh, who led the research, said: "Our research represents an important step towards the goal of generating a clinically useful artificial thymus in the lab."

Dr Rob Buckle, Head of Regenerative Medicine at the MRC, said: "This is an exciting study but much more work will be needed before this process can be reproduced in a safe and tightly controlled way suitable for use in humans."

This study was published Monday in the journal Nature Cell Biology.



Excerpts of the above story are based on information provided by University of Edinburgh.

[1] Nicholas Bredenkamp, Svetlana Ulyanchenko, Kathy Emma O'Neill, Nancy Ruth Manley, Harsh Jayesh Vaidya, Catherine Clare Blackburn. An organized and functional thymus generated from FOXN1-reprogrammed fibroblasts. Nature Cell Biology, 2014; DOI: 10.1038/ncb3023