A deceased donor liver has been preserved and kept healthy outside the body in a device that mimics the body's physiological functions and successfully transplanted into a human, for the first time in Ontario.
The technique and device are part of a Phase 1 clinical trial at Toronto General Hospital (TGH), University Health Network assessing the safety of the device, with subsequent phases examining its efficacy. First developed at the University of Oxford, the device could potentially preserve a liver outside the body for up to 24 hours. The device, called the OrganOx Metra, has been used in England, Edmonton, Spain, Germany and Belgium successfully in liver transplantation.
Clarence Mills, 43, received a deceased donor liver which has been placed on the device for almost 12 hours. "As I got sicker and sicker, it dawned on me that I might not make it," reflected Mills, who is very grateful to the deceased donor for giving him a second chance to live. Ten different markers or measures, such as production of bile and blood flow, were used to test the liver every hour, ensuring excellent functioning. In a six hour operation in July 2015, the donor liver was implanted into the patient, who is recovering well.
"I feel great," says Mills, who was able to walk around the unit two days after his transplant. Mills says he was happy to volunteer to become the first patient to receive a liver that was improved by the new technology. "I can make a difference to other patients by doing this. Researchers can learn through me and my experiences, and that's worthwhile."
"This technique will change the landscape of organ donation by improving organ preservation, allowing us to assess or 'test drive' the liver on the device before we transplant it into a patient. We will know how healthy that organ is before the transplant operation," says Dr. Markus Selzner, a transplant surgeon in the Multi-Organ Transplant Program at TGH, co-investigator of the clinical trial and the transplant surgeon who performed the donor operation. Dr. Selzner is also a clinician-scientist at the Toronto General Research Institute who modified the Steen preservation solution used in the device at TGH and supervised the research and data gathered from the device at TGH. The new preservation solution decreases inflammation and protects the liver from injury. The liver is the second organ in the body which can regenerate, after skin.
Dr. Selzner estimates that many more donor livers could benefit from this technology, since the technique and technology can potentially repair donor organs which are damaged by the current "cold storage" method of preservation. About 35% of deceased donor liver organs are not suitable for transplantation.
The medical device encloses the liver in a sterile environment, circulating oxygenated blood and nutrients into the liver at body temperature, allowing it to improve and repair itself, potentially leading to better outcomes for patients. This technology has advantages over the usual cold storage method in which a deceased donor liver is cooled to about four degrees Celsius, with no oxygen, slowing down its metabolism, and inhibiting the repair process, The liver cannot survive longer than 12 hours in cold preservation.
"Even with the shortage of donor organs, we have to decline some of our donor organs because of the damage they sustain in the retrieval process," says Dr. David Grant, Surgical Director of the Multi-Organ Transplant Program, co-investigator of the clinical trial who also transplanted the donor liver, which had been placed on the medical device, into the recipient. "This new technology can help us answer critical questions such as, 'Can we use organs which we currently decline? Can we repair and predict organ function before the transplant occurs?'"
Dr. Grant also praised the strong support and efforts of Trillium Gift of Life, which co-ordinates organ and tissue donation across Ontario, in helping to ensure that the transplant team could begin their clinical trials with this new technique.
The technique of warm organ perfusion outside the body was pioneered by the Toronto Lung Transplant Program at TGH in 2008 by Drs. Shaf Keshavjee and Marcelo Cypel to better treat, repair and assess high-risk donor lungs outside the body. The lungs are placed in a protective dome in which a system continuously pumps a bloodless solution of oxygen, proteins and nutrients into the injured donor lungs, mimicking normal physiological conditions. This makes it possible for the injured cells to begin repairing themselves, and sets the stage for more sophisticated repair techniques to be applied to donor lungs. Since 2012, there has been an unprecedented 28% increase in lung transplants at TGH as a result of this system.
At any point in time, there are about 1,500 patients waiting for a transplant in Ontario. More than 200 of these wait for a liver, and about 30% of patients die while waiting for a liver.
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