The Tissue of Life; Scientists Grow Bundles of Cells to Repair Skin, Maybe Replace Failed organs.(LIFE - SCIENCE &Amp; TECHNOLOGY)
Byline: Christian Toto, THE WASHINGTON TIMES
The budding tissue-engineering field promises one day to solve one of medicine's biggest problems, the dearth of available organs for transplantation.
For now, tissue engineering - the ability to create three-dimensional cell bundles that can replace tissue lost to trauma or disease - is being used to a modest degree nationwide. Several companies offer skin and cartilage tissue, representing the first wave of engineered organic products.
Broadly defined, tissue engineering is the development and manipulation of laboratory-grown molecules, cells, tissues or organs to replace or support the function of defective or injured body parts.
Although cells have been cultured, or grown, outside the body for many years, the possibility of growing complex tissues - literally replicating the design and function of human tissue - is a more recent development.
The process requires not only growing cells, but considering how blood vessels might grow around the new cells and whether the new tissue, such as new cartilage tissue in someone's knee, will have the mechanical strength needed to perform within the body.
Among the tissue types scientists are working on reproducing are bone, liver, muscle cartilage, heart muscles and nerves.
The intricacies of this process require input from many types of scientists, including the problem-solving expertise of engineers, needed to envision the work in three dimensions.
Others involved in the research include cell biologists, robotics engineers and specialists in computer-assisted design, who can envision how the new cells would be constructed around various scaffolding systems, or frameworks. The new cells and blood vessels begin to grow while the scaffolding dissolves.
Dr. Robert Nerem, director of the Georgia Tech/Emory Center for the Engineering of Living Tissues, says tissue engineering is in its infancy.
"In the last 10 years, it has accelerated, yet it's still very much a fledgling industry," says Dr. Nerem, whose center is exploring tissue engineering involving cardiovascular and orthopedic cells, among other uses.
Five tissue-engineering products have received approval by the Food and Drug Administration in the past year, Dr. Nerem says - four skin substitutes and one cartilage-replacement product, known as Carticel.
Once destroyed either by trauma or age, cartilage generally does not replenish itself under normal conditions.
Jennifer Elisseeff, assistant professor at the Johns Hopkins Whitaker Biomedical Engineering Institute in Baltimore, is part of a team trying to create cartilage replacement using methods similar to tissue engineering.
Ms. Elisseeff's work involves injecting a fluid filled with nutrients and stem cells from adult goats into damaged cartilage tissue, then using light to solidify the liquid. The gel provides the scaffolding while the stem cells grow into tissue similar to cartilage. Ms. Elisseeff has done the procedure with tissue in the laboratory and is preparing to try it with live animals - goats. There is no timetable as yet for human testing.
"Researchers are close to generating a very normal-looking cartilage tissue," she says. Such efforts would help those whose cartilage loss has led to pain and inflammation of the joints, she adds. …