Scientists set goal of fixing people using tailor-made body parts
By Luis Fábregas
Published: Monday, Feb. 25, 2013, 8:42 a.m.
Man-made hearts, kidneys, lungs and bladders dominate discussions about the future of medicine.
Scientists long have dreamed of repairing the human body with parts built in a laboratory — not mechanical parts, such as titanium hearts that patients use while awaiting transplants, but living parts made with the body's own army of cells.
Regenerative medicine — the process of repairing and restoring function to tissues and organs — is a rapidly advancing field, propelled by an aging population and a large number of injured troops returning from war. The Department of Defense funds many research projects.
Scientists are working to build organs to replace those that have been damaged beyond repair. In recent years, tissue-engineered skin has been used to close gaping wounds, temporarily cover burns and even treat foot ulcers in diabetics. In China and the Netherlands, scientists are working to build blood vessels.
The University of Pittsburgh and UPMC are conducting several high-profile projects with the ultimate goal of fixing the human body with engineered parts made with materials from pigs or grown in the laboratory.
“We're peeling back the complexities,” said William R. Wagner, director of the McGowan Institute for Regenerative Medicine, a program of the university and UPMC and a professor of surgery, chemical engineering and bioengineering at Pitt. “We know a lot more than we did before about how cells behave. In very well-controlled systems, we can get these cells to do things that previously we weren't able to do.”
In the past decade, several key events have brought science closer to building living body parts.
One advancement was the development of artificial bladders by scientists at Wake Forest University in North Carolina. Seven people with bladder disease received bladders made from their own cells. Each patient's bladder function improved.
More recently, doctors at Karolinska Institute in Stockholm implanted into a patient the world's first bioartificial trachea. In the 2011 surgery, doctors replaced the man's cancerous windpipe with an organ made with his stem cells grown on a plastic matrix. Doctors even gave the windpipe a blood supply.
Scientists view these achievements as key to the evolution of regenerative medicine but agree it could be decades before projects in development become standard treatment.
“There are just a lot of scientific unknowns that people are running into,” Wagner said. “There have been advancements, but there are still a lot of things that we don't know.”
One project at McGowan involves the use of a material called the extracellular matrix to repair deformities in muscles and soft tissues caused by injury, disease or wounds.
The extracellular matrix, the protein structure connecting a body's cells, has been used to restore muscle function after injury, said Dr. Peter Rubin, director of Pitt's Center for Innovation in Restorative Medicine. Scientists have relied on the cells' ability to release growth factors as a way to repair the injured tissue.
By stitching the extracellular matrix into a limb, researchers helped several soldiers enrolled in a study regain strength and mobility despite the loss of a great amount of muscle, Rubin said.
“It's too early to make definitive statements that we have regrown muscle but we absolutely have patients who have had improved function,” said Rubin, an expert on adult stem cells and chief of the division of plastic and reconstructive surgery at Pitt's School of Medicine.
Rubin said researchers intend to implant scaffolds and cells together to induce tissue growth.
“The concept of implanting a material that will then assume new tissue type is something that we already have in place,” he said. “It's a question of in what different tissues can we make this happen.”
The techniques have been used in only a few patients, not the general population, and warrant further study, he said.
“It's critical to understand that we need to develop really good solid data around these treatments to verify that they're going to work,” he said.
Pitt scientists said they are further along in a research project using fat-derived stem cells to repair facial defects after trauma and after a craniotomy, a cut that opens the skull to access the brain.
Nineteen patients — civilians and military veterans — successfully received the stem-cell treatment.
The success of these projects, Wagner said, depends on applying knowledge gained from proven procedures that use stem cells, such as bone marrow transplants.
“The key is getting that fundamental knowledge and translating it into practical knowledge,” Wagner said. “It's taking the fundamentals that we have learned around the world about how cells behave, how they differentiate, how they die, and figuring out how they generally control that process in the body of diseased patient.”
Luis Fábregas is a staff writer for Trib Total Media. He can be reached at 412-320-7998 or email@example.com.
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