I’M GREETED by the sight of several litres of pig’s blood being poured into bags on a hospital drip-stand. The red splashes on the wall and the stainless steel counters make the place feel like a butcher’s shop, but it is something altogether different. This is workshop, where he is trying to reanimate detached body parts.
Based at the University of Manchester, UK, Fildes is mainly working with pig legs and organs sourced from a local abattoir. But he is also experimenting with human organs deemed unsuitable for transplants, when they are available. The body parts are hooked up to a blood supply, which nourishes them with food and oxygen. It may sound gruesome, but this work could make more organs available for transplant, lead to new ways to treat cancer, and allow more limbs to be reattached after accidents.
The standard way of preserving a limb or organ for transplant is to put it in an ice box, similar to the kind of cooler you might use to keep beers cold. But after a few hours in cold storage, the tissue begins to deteriorate.
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Some hospitals perfuse organs with blood for a few hours. Doing this gives doctors the time to check if the organ is healthy enough for transplant, or provides a longer window to transport it across the country and get a suitable recipient ready for surgery.
But Fildes’s team wants to keep body parts alive for much longer. The group’s record so far is keeping kidneys going for 24 hours. The team hopes to soon keep a limb alive for two days, hooking it up to kidneys that will keep its perfusion fluid clean.
There could be several advantages to letting a limb sit on a shelf for a day or two. When an organ that has been on ice is put straight into a patient, the shock of oxygen returning to it can cause inflammation. This may trigger the recipient’s immune system to reject the organ.
But Fildes has found that perfusing an organ with warm blood in the lab for long enough – perhaps about 6 hours – allows this inflammation to pass. “You get it out of the way before you transplant,” he says. This may reduce the risk of rejection.
“Surgeons had to throw one man’s hand in a bin. If he’d been less injured, it could have been reattached”
People who lose limbs in accidents may also benefit. Immediately after a bad crash or a bomb blast, for example, people are often too ill to have parts reattached. The window in which it can be done is lost.
Plastic surgeon Kavit Amin of Manchester University NHS Foundation Trust has seen this happen with survivors of motorbike crashes. One example was a man in his 20s, who lost his hand. “We had to throw it in the bin. And it was such a clean cut.”
But being able to keep a limb perfused with blood for several days while its owner is in intensive care could let them get well enough for reattachment at a later date.
When Amin lugs in the first pig leg of the day – complete with skin and hair – it is reminiscent of something I might have for my Sunday lunch (excluding the trotter). But that impression vanishes when the leg is hooked up to the system. A short tube that had been sewn into the main artery is now connected to a blood supply.
Coming back to life
Soon the limb starts to look more alive: the skin flushes pink as circulation returns, and the muscles begin to twitch. Nearby, two kidneys are starting to produce urine. I can’t see any today, but Fildes says hooked-up hearts beat in the workshop for hours at a time.
If the team is successful, its techniques could open up other new medical approaches. A doctor may be able to cut off a limb that harbours an aggressive cancer, blast it with an otherwise lethal dose of chemotherapy, and sew it back on later, for example.
Or injured limbs could be reconstructed without having to keep a patient under anaesthetic. “If you had a really mangled hand and it was in lots of different parts, you may want to fix it on the machine, and only then put it back on the patient,” says , a plastic surgeon at Wythenshawe Hospital in Manchester.
Fildes can envisage his equipment one day being turned into a device portable enough for the battlefield. It will need some refinement, though – the current version is springing leaks and the lab floor is starting to resemble a bloody crime scene.
This article appeared in print under the headline “Welcome to the limb lab”
