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Entries in Bioengineering (2)

Thursday
Jun142012

Doctors Transplant Vein Grown from Patient's Own Cells

Comstock/Thinkstock(NEW YORK) -- Scientists in Sweden are reporting a medical first: a vein grown in a lab for a 10-year-old girl using her body's own cells.

Doctors are hailing the step as a milestone in tissue engineering, a field in which doctors grow windpipes, bladders, lungs and other organs to replace faulty ones while avoiding the dangerous, lifelong complications of organ transplants.

While a handful of doctors around the world have had success growing blood vessels and other organs and transplanting them into patients, doctors said this is the first time a vein has been lab-grown and successfully transplanted using cells and parts taken entirely from the human body.

"To many of us working in this field, it is a validation of what we believe will be a revolution in medicine," said Dr. Adam Katz, director of plastic surgery research at the University of Florida.

Suchitra Sumitran-Holgersson, one of the authors of a report on the transplant published Wednesday in the Lancet journal, said the experimental procedure could someday bring promise to patients needing new blood vessels for dialysis or coronary bypasses.

Sumitran-Holersson and her colleagues grew the vein for a 10-year-old girl who had a blockage in the vein connecting her intestines and spleen with her liver. The rare condition can cause life-threatening bleeding, delayed development and even death. The patients often need a graft of a vein to replace the blocked one.

In this new approach, doctors took about 3.5 inches of a vein from the groin of a 30-year-old deceased donor and, in the lab, scraped away all of the donor's cells, leaving just the protein scaffolding of the vein. Doctors then took cells from the bone marrow of the 10-year-old girl and seeded the vein scaffolding with them. Then, for two weeks, they waited for the cells to grow.

The result was a blood vessel engineered entirely from human tissue. When surgeons took the vein and used it to replace the faulty vein leading to the girl's liver, normal blood flow was restored almost immediately, the researchers said.

The vessel had to be repaired after nine months when hardened scar tissue in the girl's body put too much pressure on the transplanted vessel.

A year after the transplant, the girl has grown nearly 2.5 inches, gained 11 pounds and has even taken up light gymnastics. So far, her body also shows no signs that it will reject the vein. But doctors will have to make sure that the vein and the liver stay healthy.

"When we met her last week, she was somersaulting and talking away," Sumitran-Holgersson said. "So far, she is doing very well."

Even though the results are exciting, doctors remain cautious about their implications for patients who need vein grafts for more common conditions, such as dialysis or coronary bypasses. The process of harvesting a donor's vein and covering it with the girl's own cells was nearly as complicated and costly as the process for an organ transplant.

"The organization and resources required for this process are significant and would severely limit the applicability of the treatment strategy to large groups of patients," said Dr. William Marston, chief of vascular surgery at University of North Carolina Hospitals.

Some cardiovascular surgeons said many patients having coronary bypasses have no shortage of their own arteries and veins that can be used in those surgeries. And many patients can't wait for treatment while doctors grow a vein for them.

Also, the fact that the graft needed repair after a year is a concern.

"A uniform conduit such as a perfectly sized and available bioengineered vein would be of great utility, but it needs to last closer to a lifetime, not a year," said Dr. John Calhoon, a professor of head and thoracic surgery at the University of Texas Health Science Center.

Sumitran-Holgersson said more work will need to be done to work out the kinks in the process and to test it in other patients. But she remains optimistic about scientists' ability to create personalized blood vessels and other organs, reducing the need for a lifetime of drugs and surgeries.

"This is a very exciting technique and one that can greatly improve a patient's quality of life after transplantation," she said. "I think we're going to see quite a bit of this in the future."

Copyright 2012 ABC News Radio

Monday
May232011

Lab-Grown Meat: Food of the Future?

Jupiterimages/Thinkstock(CHARLESTON, S.C.) -- Next time you fire up the grill for a backyard barbecue, think about this: at some point in the future, those steaks sizzling over the flames might not come from livestock, but a lab.

For some scientists, so-called "test-tube" meat has been the dream of decades. And fueled by concerns about the consequences of meat consumption for our health, the environment and animal welfare, the movement is gaining momentum.

At universities in the U.S. and Europe, researchers are working to develop lab-grown meat that looks and tastes like the real deal.  And one leading bioengineer said he's even drawing up a business plan for a start-up that would bring synthetic meat to market.

"I think the future of human food, is food that becomes not just a way to survive, but also a way to become better," said Dr. Vladimir Mironov, an associate professor at the Medical University of South Carolina.  "Most people try to imitate natural meat -- it must be the same taste, texture, structure.  What I want to say is that we can create better than nature -- not just food, but a 'nutraceutical.'"

Do you like your steak extra fatty or wish that it could boost your brain power? Mironov said that with a little bit of bioengineering those benefits can be baked into a final product.

For the past decade, Mironov has been working to develop lab-grown meat from stem cells bathed in a nutrient-rich bioreactor mixture.  With the help of Nicholas Genovese, a research associate funded by People for the Ethical Treatment of Animals (PETA), he's experimented with ways to engineer nutrition and taste into cultured meat.  Now, he's working up plans to turn his research into a diner's reality.

To make cultured, or in vitro, meat, scientists take the cells from an animal and then let them grow in a plant-based mixture of nutrients.  As the cells develop, they attach to a natural scaffold (or biodegradable foundation) to create the muscle tissue that comprises meat -- all without the raising and slaughtering of animals.

Copyright 2011 ABC News Radio







ABC News Radio