Ordinarily, when a donated kidney is waiting to be transplanted, it's cooled on ice. Doctors from Toronto General Hospital (part of the University Health Network, or UHN) have become the first in North America to try another technique, however. They've kept a deceased donor kidney alive at body temperature, using an altered heart-lung machine.

In an effort to increase the number of kidneys available, doctors have turned to using "extended criteria" organs. These are typically from older donors, or donors with one or more risk factors such as hypertension, high body mass index, diabetes, or death due to stroke.

Such kidneys often don't do well when stored on ice. They can't repair damage that they sustained during the retrieval process, and end up becoming "sleepy kidneys" – this means that they function poorly upon transplantation, requiring the patient to be on dialysis for days or even weeks. Even once the kidneys are up and running properly, that early delayed function still negatively affects their long-term survival.

That's where ex vivo organ perfusion comes in. Previously used on donated lungs, it utilizes a converted heart-lung bypass machine to mimic the body's physiological functions. It does so via tubing that pumps a warm mixture of blood, nutrients, minerals, amino acids, oxygen, glucose, antibiotics and drugs through the extended criteria kidney.

As a result, not only does the organ remain alive, but because its metabolism isn't slowed down, it's able to begin repairing damage. This means that the chances of it becoming "sleepy" when implanted are much lower.

The Toronto General Hospital procedure was carried out late last November, led by Dr. Markus Selzner and performed on patient Zhao Xiao. It involved placing the donor kidney on the device for 3.5 hours, after which it was successfully transplanted into Xiao's body.

The kidney immediately turned "ruby-red" and began pouring out urine, meaning that it was functioning normally. Additionally, tests performed within 48 hours showed that it was effectively removing wastes and excess fluid from the blood.

"This technique will change the landscape of organ donation by improving organ preservation, allowing us to better assess and regenerate the donor organ on the device before we transplant it into a patient," says Selzner. "We will know how healthy that organ is before the transplant operation."

Other researchers involved in the development of the technique include UHN transplant surgeons Drs. David Grant and Anand Ghanekar, along with Drs. Lisa Robinson and Darius Bagli from The Hospital for Sick Children.

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