Getting organ-ized: Failing organs are the subject of new medicine that sounds like something out of science fiction -- from growing parts from stem cells to transplanting organs from pigs, writes Free Press reporter Mary Jane Egan.

By MARY JANE EGAN, FREE PRESS REPORTER
London Free Press
Apr. 13, 2006

The world dawned to a new age in science this month when U.S. researchers successfully implanted the first lab-engineered bladders into children and teens -- organs grown from the patients' own cells.

The stunning accomplishment is a glimpse into the future of medicine -- one in which doctors may one day routinely order up newly grown living body parts to replace failing organs.

Or, says Dr. Anthony Jevnikar, a scientist at the Lawson Health Research Institute, doctors may prod the body into regenerating itself.

Jevnikar believes stem cell research could revolutionize medicine in ways we would have once dismissed as science fiction.

Stem cells are master cells that can generate most of the cell types in the human body and hold out hope for treating an array of medical problems, from heart attacks and Alzheimer's disease to Parkinson's, diabetes and spinal cord injuries.

"If we learn all the signals that direct stem cells and how they divide and how they regenerate, would we really need to grow them in a test tube in a laboratory?" Jevnikar asks. "Why not just grow them where they're intended (in the body)?"

Jevnikar believes the day will come when injury will be detected early enough that doctors will intervene before organ damage.

"We may be able to alter that balance very early and take our own endogenous capacity to repair ourselves and abandon this idea of having to inject things and sew in new organs," he says.

But we're not there yet.

Jevnikar and fellow Lawson scientist Dr. Robert Zhong, who is also Canada research chair in transplantation and experimental surgery, are part of a team making world- leading advances in the greatest enemy of organ transplants -- rejection.

Even 45 years after the first successful kidney transplant, it's estimated 10 per cent of patients will have one rejection episode in the first year after surgery, while up to 60 per cent will experience chronic rejection within 10 years.

By combining a "monoclonal antibody" discovered by Zhong and Jevnikar's team in collaboration with Dutch researchers with conventional anti-rejection drugs, Zhong has seen impressive improvement in the post-transplant survival of mice and primates.

It's hoped such treatments in humans will allow doctors to use a lower dose of conventional anti-rejection drugs and minimize such harmful side-effects as hardening of the arteries, kidney damage and vascular disease.

But medical advances don't change the grim statistics that demand far outstrips supply of useable organs.

It's estimated 4,000 Canadians are awaiting organ transplants -- about 1,900 of them in Ontario -- and the list keeps growing.

In Canada, 30 per cent of people awaiting life-saving organs die on the waiting list.

An aging population and the scourge of diabetes are aggravating a critical shortage of useable organs, says Jevnikar.

Zhong believes the fast-breeding pig is the answer.

London is among Canada's pioneers in animal-to-human transplantation, or xenotransplantation.

Zhong has had success with mouse-to-rat transplants in tricking the immune system into believing the transplanted organ is not a foreign invader.

By tinkering with the pig's genetic makeup to contain high concentrations of human genes, Zhong believes xenotransplants are a future medical certainty.

And with aging baby boomers falling victim to Type 2 diabetes in record numbers, Zhong believes transplantation of pig islets into humans could occur within five years.

There are two types of diabetes. In Type 1, the immune system destroys the islet cells in the pancreas that make insulin. In Type 2, the more common form of the disease, the body's cells are not sufficiently receptive to insulin or the pancreas makes too little of it, or both.

"No one can expect we'll use pigs for humans tomorrow," says Zhong. "But I believe with knowledge and genetic modification of the pigs, this will be a reality. It's why I am so passionate for xenotransplantation."

Zhong notes a Minnesota lab has successfully transplanted pig islets into monkeys who have survived more than 150 days.

"This is remarkable progress," he says.

And Zhong notes extensive research is allaying earlier fears xenotransplants would lead to cross-species infections.

In fact, Zhong believes pig organs will actually be preferable to those of cadavers because they won't bring to transplants such human foibles as smoking, alcohol abuse and high cholesterol-laden diets.

BATTLING DIABETES

- London is home to Ontario's only islet isolation laboratory located at London's Stiller Centre of Biotechnology. In the lab, insulin-producing islet cells removed from deceased donors remain frozen pending approval to launch an islet transplantation program here. Once approved, London would be the third such centre in Canada, after Edmonton and Vancouver.

- London is home to some of the most powerful and sophisticated imaging devices in the world. Dr. Anthony Jevnikar, a scientist at the Lawson Health Research Institute, notes there is no one test to determine if a child will develop diabetes. "But," he adds, "if you had a risk in your family and we had a way of actually imaging the cells around your islets, then there would be time to intervene and you'd never get diabetes."