How deep-frozen organs could spell the end of transplant waiting lists

Currently, donor organs such as hearts, livers and kidneys must be transplanted within hours because of the rate at which their cells die.

But American scientists have successfully transplanted frozen organs in
animals up to three months later and their breakthrough could one day spell the end of transplant waiting lists.

Currently donor organs must be transplanted within hours because of the rate at which their cells die

The scientists, who are based with the Californian company Human BioSystems, removed a kidney from a rat and froze it for three months at temperatures as low as -80C using a special solution.

The organ was slowly brought back to a temperature of about 4C and transplanted into another rat.

It was then removed again to be closely analysed. The analysis, known as a histology, showed that the cell structure and tissue of the organ had been largely preserved.

Similar solutions are in use across the world to preserve organs but this new one, known as HBS-BZ, is the first to work at subzero temperatures.

Dr Luis Toledo, the transplant surgeon leading the pioneering scientists in America, said: ‘Normally organs stored under such conditions sustain irreparable damage to the tissue and do not function after thawing. We are very encouraged by our recent results.’

One of the UK’s leading transplant surgeons, Keith Rigg, also welcomed the breakthrough. He said: ‘We will be looking at extending the life of donor organs at some point in the next few years.’

Previous attempts to freeze organs have failed because the process damages cell structure.

But the new solution – a mixture of essential amino acids, cell protection compounds, stabilising compounds and an antifreeze agent – does not freeze until -20C.

When it does, molecules form spheres rather than the jagged edges usually formed when water freezes, which means the cell structure is not damaged.

Official figures show 30,813 viable organs made available under the NHS Organ Donor Register have not been used over the past ten years.

There are currently 7,791 people waiting for transplants in the UK.