The first complete and functional organ has been grown in a living animal, by British scientists.
This has opened the door for the method, which has only thus far been tested on mice, to be used to offer replacement organs for humans with weakened immune systems and could result in more complex organs being grown for transplant. It is possible that the method may be used in humans in the next decade.
Scientists have created a thymus, a ‘nerve centre’ which is located close to the heart, with tissue cells from the embryo of a mouse which they changed into a different cell strains by turning a genetic ‘switch’ in their DNA. The resultant cells spontaneously grew into the entire organ when it was injected into the mouse, along with other cells.
The leader of the team of scientists, Professor Clare Blackburn, based at the Medical Research Council (MRC) Centre for Regenerative Medicine at the University of Edinburgh, said being able to grow replacement organs from cells is one of the ‘holy grails’ of regenerative medicine. However, the complexity and size of organs grown in the lab has been limited.
She said the direct reprogramming of cells has allowed them to produce an artificial cell type, which, when transplanted was able to form a fully functional and organised organ. She said this was a vital first step towards their goal of creating a clinically useful artificial thymus in the laboratory.
The thymus is the main hub of immune systems which sends out T-cells to fight infection. People who have a defective thymus lack the crucial functioning T-cells, which makes them vulnerable to infections. This is particularly dangerous for bone marrow transplant patients who require a working thymus to rebuild their immune systems after undergoing surgery.
About 4000 babies are born each year in Britain with a malfunctioning or an absent thymus, caused by rare conditions, such as DiGeorge syndrome. These disorders can be treated by infusing extra immune cells or transplanting a new organ soon after birth. However, there are limitations to these methods of treatment due to tissue rejection and a lack of donors.
Parts of organs, such as livers, brains and hearts have been grown from stem cells, but no one has yet been successful in producing an intact organ from cells which have been created outside the body.
The head of regenerative medicine at the MRC, Dr Rob buckle, said this new technique could eliminate the need to transplant complete organs from one person to another, as a lack of donors is always a problem. However, he said much more work is necessary before this process can be replicated in the lab, in a safe and controlled way which will make it suitable for use in humans.
A professor of regenerative medicine at University College London, Chris Mason, said that the resources and time required to turn this study into an effective and safe therapy for patients will take millions of pound and at least 10 years. He added that not all the cells that are needed can be made in the lab yet.
Image Credit: Jing