Scientists have grown an artificial rat kidney in the laboratory, heralding an era when humans can replace their own knackered organs with off the shelf stand-ins.
Boffins at Massachusetts General Hospital used a technique which had previously been used to create fully working hearts, lungs and liver tissue.
They first took a kidney and extracted its functioning cells using a detergent solution. This leaves behind the cellular “scaffolding” that gives the organ its shape.
The team then implanted kidney and blood vessel cells onto the scaffold, which was left to grow for 12 days until the cells had grown all the way around the structure.
This horrifying-sounding contraption was then transplanted into a living rat, where it performed like a kidney should, filtering blood and producing urine.
Although it wasn’t quite as good as the kidney nature endowed the rat with, boffins were pleased with the results.
The method was originally pioneered by American bioengineer Doris Taylor, who first used it in 2008 to grow beating hearts.
Harald Ott, of the Massachusetts General Hospital’s Centre for Regenerative Medicine, is cautiously optimistic the technique could be used on humans suffering from kidney failure.
"What is unique about this approach is that the native organ's architecture is preserved, so that the resulting graft can be transplanted just like a donor kidney and connected to the recipient's vascular and urinary systems," he said.
"If this technology can be scaled to human-sized grafts, patients suffering from renal failure who are currently waiting for donor kidneys or who are not transplant candidates could theoretically receive new organs derived from their own cells."
Kidney failure is a grim and largely untreatable disease. The only ways to combat it are dialysis or replacing the kidney with a donor organ, dooming the patient to a lifetime of taking immunosuppressant drugs. Growing kidneys from a patient’s own cells would remove the need for these drugs, as the body would not reject the organ.
Ott said that more work was needed to make the kidney cells work more efficiently.
"Further refinement of the cell types used for seeding and additional maturation in culture may allow us to achieve a more functional organ," he added.
"Based on this inital proof of principle, we hope that bioengineered kidneys will someday be able to fully replace kidney function just as donor kidneys do. In an ideal world, such grafts could be produced 'on demand" from a patient's own cells, helping us overcome both the organ shortage and the need for chronic immunosuppression.”
His team are now looking into ways of harvesting human cells and refining their technique to handle man-sized kidneys.
The arrival of the artificial rat organ was welcomed by Kidney Research UK, who also warned that a human treatment was still a long way away.
Elaine Davies, head of research operations, said: "This whole regenerative medicine approach is still really in its infancy in terms of kidney disease. Predominantly, it's just the fact that the kidney is a much more complex organ to replicate when you compare it to other organs like skin or heart. It has many different types of cells within it and it has a very complex structure in terms of the different functions it performs.
"There's hope with a caution. I'm not saying we won't get there but it could be in decades' time."
She claimed there are 3million people at risk of contracting kidney disease, which is a “growing health burden”.
Doctors are failing to identify enough patients at an early stage of the illness, when lifestyle changes could prevent kidney failure, Davies added.
More than 51,000 people are treated every year in the UK for terminal kidney failure and 90 per cent of people on the organ donation waiting list are waiting for kidneys. Some 3,000 transplants are carried out a year, whilst 3,000 people die waiting for a transplant.
The research was published in the journal Nature Medicine. ®