New surgical technique allows doctors to add more organs to the donor pool

Two types of light-based therapies can sterilize donor organs prior to transplantation

New surgical technique allows doctors to add more organs to the donor pool

A new technique co-developed by U of T researchers uses light-based therapy to kill viruses in organs meant for transplantation. The method lets physicians treat human donor lungs infected with Hepatitis C, preventing viral transmission to the organ recipient.

The co-authors of the procedure, published in Nature, are hopeful that it could vastly increase the number of organs eligible for transplantation in North America.

The new surgical technique is based on existing methods

This technique uses an existing procedure known as ex-vivo lung perfusion. Here, after retrieval by practitioners, the lungs are placed in a chamber with a circuit and specific liquids flow through the organs’ vasculature.

During this circuit the solution passes through the lungs, washing out a lot of viruses. The newly developed technique uses a machine with two light-based therapies — namely, ultraviolet C irradiation and photodynamic therapy — to eventually sterilize the organs before the transplantation.

The research team developed a customized illumination device which is attached to the machine where perfused liquid passes through, irradiating the virus and therefore inactivating it with light.

The researchers aim to further develop the technique by treating the lungs themselves with light, not just the liquid that passes through them. To achieve this, more research is needed on the optical properties of the lungs to engineer new technology to illuminate them.

Adding organs to the donor pool

Co-author Dr. Marcos Galasso, a U of T thoracic surgeon and ex-vivo lung perfusion specialist, stressed the importance of this new technique in an interview with The Varsity.

“There is a great need for donor organs,” he said, “[which has led] to some people dying on the waiting list for transplantation.”

Galasso added that treating Hepatitis C-infected donor lungs alone could make a huge impact on the donor pool due to the opioid crisis gripping North America. He noted that most patients who die from drug overdoses test positive for the virus.

According to Galasso, if health care practitioners could add volunteers infected with Hepatitis C to the donor pool, there could between 1000 to 2000 new lung donors eligible per year in North America.

“We could actually have a massive impact in the organ donation environment in North America [with this surgical technique].”

Life-saving machine mimics the body to sustain pre-transplant kidneys

Toronto doctors revolutionize traditional transplant procedure

Life-saving machine mimics the body to sustain pre-transplant kidneys

Imagine you are an athlete competing in the Mount Everest Marathon, one of the longest endurance races in the world. Before you even start the race, you must navigate for countless hours through uncharted territory, hungry and out of breath. Race day arrives, and you are expected to be at your peak performance to start your run. Sounds daunting, doesn’t it? Now imagine you are running because your life depended on it.

This scenario is similar to the life-saving race that kidneys go through after they are harvested from donors and are awaiting transplant. Fortunately, a team of Toronto doctors found a way for these organ-athletes to start the race strong and full of energy before transplant day.

The Varsity had a chance to speak with Dr. Markus Selzner, a leading transplant surgeon from Toronto General Hospital and Associate Professor in U of T’s Department of Surgery, about this new life-saving method.

With collaborators from the University Health Network, Sick Kids Hospital and support from the Canadian National Transplant Research Program, it took about five years of research to develop the ex-vivo machine. Named for the Latin term meaning ‘out of the living,’ the machine can mimic the environment inside the human body to keep organs healthy before transplant.

In contrast, standard transplantation procedure involves removing kidneys carefully from a body’s balmy internal temperature of 37 degrees and cooling them down to about four degrees. This cooling slows the kidney’s metabolism and keeps them viable for a maximum of 30 hours before transplantation. These cooled kidneys are in a ‘sleepy’ state, which requires dialysis until it can be transplanted.

The ex-vivo machine blends old and new techniques by combining the traditional heart-lung bypass machine with customized tubing that is adapted to maintain optimal flow of the kidney’s smaller blood vessels. A series of interconnected tubes and mechanical pumps carry a solution of nutrients including amino acids, oxygen, glucose, antibiotics, and drugs to treat and relax the kidney in preparation for surgery. “The key is what’s in the fluid. It’s like cooking a soup, you want to get every ingredient right,” said Selzner.

The goal of the device is to preserve and rejuvenate less-than-ideal kidneys by mimicking the “normothermic” or normal temperature inside the body. “We keep the kidney warm, perfused with oxygen and nutrition, so we pretend that the organ is still in the body… and it works at this time,” said Selzner.

In Canada, kidneys are the most frequently transplanted solid organ, but the need for this organ exceeds the supply. These kidneys go through rigorous analysis and only the most healthy organs are chosen to ensure success for the patients receiving them. Selzner hopes that by meeting this demand through rejuvenating less-than-ideal kidneys, countless individuals will be given a new lease on life.

Selzner has an optimistic outlook of what is to come and emphasized the importance of collaboration between research and clinical teams to advance life-saving technologies. Selzner is part of the team seeking new applications for this technology including rejuvenating other organs like the liver, pancreas, and heart.

In the long term, he is hoping to create a central hub or repair center for organs which would involve organs being docked and actively analyzed for up to date information on how well it works pre-transplant. This would be an significant advancement in accessibility and availability of organs for transplant.