Hopes have been raised of a futuristic new treatment in which patients could grow their own new organs, after a breakthrough by British scientists.
Experts have managed to create cells which, once injected into the body, can grow into a fully functioning organ.
The research, conducted in mice, raises the prospect of a future solution to kidney problems, liver failure and heart defects.
While at a very early stage, the research signifies a dramatic step forward in the drive to end the reliance on transplanted organs.
Professor Clare Blackburn at the University of Edinburgh, who led the research, said: ‘The ability to grow replacement organs from cells in the lab is one of the holy grails in regenerative medicine.
‘By directly reprogramming cells we’ve managed to produce an artificial cell type that, when transplanted, can form a fully organised and functional organ.’
‘This is an important first step.’
While fragments of organs, including hearts, livers and even brains, have been grown from stem cells on the laboratory bench, no one before has succeeded in producing a fully intact organ from cells created outside the body.
It might be another ten years before such a treatment is shown to be effective and safe enough for human patients, but the research was welcomed as an exciting new breakthrough.
The researchers, whose results were published last night in the journal Nature Cell Biology, used the fledgling technology to grow an artificial thymus in a mouse.
The thymus, a small organ near the heart which is central to the workings of the immune system, grew from a few cells until it functioned in the same way as one found in any healthy adult mouse.
The scientists took cells called fibroblasts from a mouse embryo and ‘reprogrammed’ so they acted as thymus cells.
The technique effectively meant the cells acted as they would in a foetus in the womb, when a tiny baby grows organs for the first time.
When mixed with other thymus cell types and injected into mice, the cells formed a replacement organ that had the same structure, complexity and function as a healthy native adult thymus.
The thymus works by producing T-cells – the cells which guard against disease by scanning the body for malfunctioning cells and infections.
When they detect a problem, they mount a coordinated immune response that tries to eliminate harmful cells, such as cancer, or pathogens like bacteria and viruses.
Crucially, the researchers found that the artificial thymus could produce the T-cells, raising hope for the one in 4,000 babies born each year without a functioning thymus.
Dr Rob Buckle, Head of Regenerative Medicine at the Medical Research Council, which funded the study, said: ‘Growing replacement parts for damaged tissue could remove the need to transplant whole organs from one person to another, which has many drawbacks – not least a critical lack of donors.
‘This research is an exciting early step towards that goal, and a convincing demonstration of the potential power of direct reprogramming technology, by which once cell type is converted to another.
‘However, much more work will be needed before this process can be reproduced in the lab environment, and in a safe and tightly controlled way suitable for use in humans.’
The scientific community last night welcomed the finding as something that could ‘dramatically transform patients’ lives’.
Professor Chris Mason of University College London said: ‘Using living cells as therapies has the big advantage in that the functionality of cells is many orders of magnitude greater than that of conventional drugs. Nowhere is this level of functionality more needed than in curing disorders of the immune system.
‘The major advantage would be a once-only, off-the-shelf, cell transplant compared to the current practice of tracking down potential donors who may then prove unsuitable or may not be found in time.
‘The time and resources required to turn this mouse proof of concept study into a safe and effective routine therapy for patients will be very significant – ten years and tens of millions of pounds at a bare minimum.
Prof Robin Lovell-Badge, head of developmental genetics at the National Institute for Medical Research, added: ‘This appears to be an excellent study combining several approaches, each of which has been known to work in other systems.
‘This is an important achievement both for demonstrating how to make an organ, albeit a relatively simple one, and because of the critical role of the thymus in developing a proper functioning immune system.’