More doctors turning to animals for tissue transplants

By Maureen McFadden WNDU.com

One in 20 people will need some kind of tissue transplant in their lifetime, and more surgeons are turning to animals for help.

Whether they've lost an ear to a bomb or their hearing to old age, medicine is crossing the species boundary to unlock the secrets of disease and re-grow what was lost.

The animals in Dr. Joseph Vacanti's lab are on the cutting edge of regenerative medicine.

We actually used human cartilage cells in a human ear shape and then on the back of this mouse, the human cartilage cells grew into a human ear,” says Dr. Vacanti, chief of pediatric surgery at the Massachusetts General Hospital for Children in Boston.

Within a year, he plans to re-grow an ear on a human in a similar way.

“We can give somebody back their own face that's been either ravaged by cancer or destroyed by a terrible accident or injured by war,” he says.

Pigs are huge helpers when it comes to healing.

“Believe it or not, their genetic makeup is pretty close to humans,” says Dr. Samer Mattar, bariatric surgeon at Clarian Bariatrics in Indianapolis.

Surgeons use material made from the pig's small intestines to repair torn muscles caused by hernias. Pig powder is re-growing severed fingers at the University of Pittsburgh.

“The simplest applications involve just being able to spread a powder or a particular form of the powder on the wound site so it can affect the wound healing process,” says Dr. Steve Badylak, director of the McGowan Institute for Regenerative Medicine in Pittsburgh.

From land to the sea, fish are helping scientists fix hearing disorders.

If zebra fish lose hearing, they naturally re-grow new auditory cells. Scientists are studying the genetic process to restore hearing in humans. Doctors hope to eventually end deafness.

Animals are advancing medicine and teaching humans better ways of healing.

According to research found in the Journal of Transplantation, transplants from pigs might actually be safer than transplants from humans in the long run.

Experts say humans and zebra fish share about 80% of the same genes.

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Human transplants from pigs

There's been some exciting transplant research emerging that is sure to have an impact on increasing the donor pool and getting more patients off waiting lists. Xenotransplantation could save thousands of patients waiting for donated organs. The animal organ, probably from a pig or baboon could be genetically altered with human genes to trick a patient’s immune system into accepting it as a part of its own body. They have re-emerged because of the lack of organs available and the constant battle to keep immune systems from rejecting allotransplants. Xenotransplants are thus potentially a more effective alternative. This article describes the success achieved with transplanting pig tissue.

HealthFirst - ABC.com

Pigs make some of the best donors for human transplants.

HealthFirst reporter Leslie Toldo tells us why humans seem to thrive with at least one type of transplant from pigs.

We are talking about tissue transplants, and from hernias to plastic surgery, pigs are helping a lot of humans out.

A few years ago, moves like these didn't come easily for Chris Nelson. "I was having pain even standing for an extended period of time."

Nelson had a hernia in his groin. The muscle had torn. Instead of using donor tissue, doctors repaired it with material made from the small intestines of pigs.

"It did seem almost weird science or something like that," Nelson admitted.

"Pigs have been a very popular or common animal to use. Believe it or not, their genetic makeup is pretty close to humans," said bariatric surgeon Dr. Samer Mattar.

When placed on the torn tissue, the body uses the pig part as a scaffold or guide to remodel and repair itself. Over time, the pig's tissue is replaced by human tissue, providing a permanent repair.

"Over time, it's very hard to distinguish where the graft or the pig's tissues are versus the patient's," Mattar said.

Besides hernias, the pig tissue can be used in ulcer repair, wound care, plastic surgery and weight loss surgery. Doctors say, compared to a human donor, the pig tissue has less risk of causing an allergic reaction.

"No pain whatsoever. It's great," Nelson said.

"I would say my game's getting better, but I probably wouldn't be honest at that point."

But he's satisfied with simply feeling better.

There is a chance the body will see the animal based tissue as a foreign and reject it.

BACKGROUND: Human cells or tissue can be used for implantation, transplantation or infusion into a human recipient. A transplant occurs when a recipient's damaged or failing organ or tissue is replaced with a functioning one from a donor. Donors can be living or deceased. Organs that can be transplanted include the heart, kidneys, liver, lungs, pancreas and intestine. Bones, tendons, cornea, heart valves, veins and skin are types of tissues than can be transplanted.

RISKS: Rejection is a major concern with transplants. This happens when the body does not accept the transplanted organ or tissue. During rejection, the body's immune system attacks the transplanted organ or tissue, which causes failure of the transplant. The rejected organ or tissue must then be removed and the patient must wait for a different one. However, tissue transplants have a lower rejection rate than organ transplants.

According to the American Association of Tissue Banks, over the past 20 years, there have been more than 10 million tissue transplants. However, like many other medical procedures, tissue transplants carry their own risks. To lower these risks, tissue donors are screened and tested for a wide range of diseases. In addition, the tissue is thoroughly processed in systems that can destroy or inactivate any bacteria or viruses.

PIGS AS DONORS: Transplantations between two different species, such as pigs and humans, is known as xenotransplantation. Pig skin and pig valves have been used in human transplants, but not entire organs. Research shows when a tissue is torn in a human, the body can use tissue from a pig's small intestine as a guide to repair itself. Over a period of time, the pig tissue assists in regenerating the human tissue, forming a permanent repair. According to research found in the journal Transplantation, transplants from pigs might actually be safer than transplants from humans in the long run. Jeffrey Platt, M.D., head of the Transplantation Biology Program at the Mayo Clinic, says advanced organ screening for infections and other problems and the freedom to schedule surgery in advance may better prepare the patient's immune system for the foreign tissue.

One major concern with species-to-species transplants is transmission of animal disease to humans. However, studies have shown that pigs are healthier and carry fewer diseases than other animals. In addition, compared to other animals, their anatomies are more similar to humans.

“You Have the Power to Save Lives – Sign Your Donor Card & Tell Your Loved Ones of Your Decision”

Register to be a donor in Ontario or Download Donor Cards from Trillium Gift of Life Network. NEW for Ontario: recycleMe.org - Learn The Ins & Outs Of Organ And Tissue Donation. Register Today! For other Canadian provinces click here

In the United States, be sure to find out how to register in your state at ShareYourLife.org or Download Donor Cards from OrganDonor.Gov

In Great Britain, register at NHS Organ Donor Register

In Australia, register at Australian Organ Donor Register

Your generosity can save up to eight lives with heart, kidneys, liver, lungs, pancreas and small intestine transplants. One tissue donor can help up to 100 other people by donating skin, corneas, bone, tendon, ligaments and heart valves

Has your life been saved by an organ transplant? "Pay it forward" and help spread the word about the need for organ donation - In the U.S. another person is added to the national transplant waiting list every 11 minutes and 18 people die each day waiting for an organ transplant.

Britain squanders pioneer work on organ transplants

Scientists have been exploring the use of animal organs, mainly from pigs, as a way of ending organ shortages. The procedure is called xenografts or xenotransplantation. For an overview and discussion of the pros and cons see the Wikipedia article.

From Times Online:

By Robert Winston

A new patient is put on a waiting list for a transplant somewhere in the developed world every 15 minutes. Only a few of these people will get a transplant, the rest will die with increasing incapacity. Worse still, far more patients needing transplantation will not even get on a waiting list.

People waiting with crippling heart disease cannot walk more than a few paces, or sleep properly because of severe breathlessness. Patients with kidney and liver failure are slow-poisoned, alleviated to some extent with artificial blood-cleaning machines. Most of them have a hugely restricted life.

People needing a new heart or liver are waiting for someone else to die - usually a violent death in a traffic accident. So my team at Hammersmith hospital in west London has been trying to modify pigs so their organs might save the lives of humans.

Why consider animal organs at all? Well, human-made devices such as mechanical hearts never work as well as biologically produced organs. And although huge publicity has been given to the idea of growing organs - culturing hearts or livers possibly from stem cells - this technology is still very primitive and is very unlikely to come to fruition in the next 20 or 30 years, if ever.

Pigs’ organs are the right size for human transplantation, and they work similarly to human organs. Of course this raises a moral problem, but it is much more ethical to use a pig to save a human life than to use it for relatively unnecessary meat eating.

And pigs for transplantation are kept in scrupulously humane circumstances and killed under proper anaesthesia.

The key challenge is introducing the right genes into pigs. These genes do not change the pig - it feels and looks entirely normal - but the genes change proteins on the surface of their organs so they will not be recognised as “foreign” by the human immune system after transplantation. Patients will still need to take drugs to prevent rejection, but the graft should be tolerated.

One problem is that it is hard to get new genes into large animals. The technology works in mice, but is still inefficient and requires hundreds of mouse embryos to get the occasional successful “transgenic” - an animal carrying the genes needed. Obtaining embryos in large animals is excessively difficult and sometimes the surgery may not be as humane.

My colleague Carol Readhead, a scientist from California, and I hit on a drunken idea over a bottle of good burgundy a few years ago. Pigs’ embryos are difficult to harvest, but pigs produce copious semen. This is not something you may want to know over breakfast, but the average male pig produces a large cupful with each ejaculation - carrying perhaps 1 billion sperm.

Our drunken idea was to introduce the genes we needed into the sperm. Whenever the pig mated, the egg would fertilise naturally and any embryo would carry the genes. A simple injection of our gene product into the testicle of a piglet is all that is needed. As the male pig grows, it will continue to produce many modified sperm for years. And this single injection, under local or general anaesthetic, is painless.

One problem with animal organ transplants that has raised public concern is that animals such as pigs harbour viruses that could infect any human organ recipient. Some of these viruses might cause terrible diseases such as cancer. And another possibility is that viruses from pigs, once established in humans, might go on to infect many members of the population.

However, there are likely to be several strategies to minimise the risk. First, the evidence suggesting it may be possible to breed virus-free pigs. Similarly vaccines might be developed that could prevent any viruses taking hold in humans. And we also have evidence that pig viruses have not necessarily caused problems when pig tissues have been transplanted into other species. Pig valves are widely used in heart surgery without ill effects.

This technology is important for human medicine. As a bonus, it carries huge commercial opportunities if we develop and export it around the world. However, it has been difficult to pursue the research in the UK. Getting a Home Office licence to experiment with just six pigs took nearly two years with successive delays, even though the pigs do not suffer.

And having got pigs producing transgenic sperm, we were informed we could not mate them because of some Department for Environment, Food and Rural Affairs and European Union regulations. We are not even permitted to do postmortems on the pigs, so we cannot prove we have been successful. Years of work, and investment, have been mostly wasted. And we have had to say a sad goodbye to our committed scientific team.

In the present commercial climate it is difficult to get further UK funding, so the experiment will move to the States. Our US friends will benefit from our technology and yet another British innovation will be jeopardised; the income we might have generated for Britain will be lost. If we wish to ensure that we are in the forefront to alleviate suffering, we must avoid needless bureaucracy when developing important technological advances.

Lord Winston is a leading fertility consultant and broadcaster.

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For other Canadian provinces click here

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Your generosity can save up to eight lives through organ donation and enhance another 50 through cornea and tissue donation