Bio-Engineered Tissue Constructs
For several decades, scientists have cultured individual cells and single layers of cells in media outside the body. Information on cell growth, function, and pathology has accumulated from studying these tissue cultures. Very recently, the technology for growing three-dimensional cultures, called tissue engineered constructs (TCE), has evolved. This new technology relies on growing tissues in low gravity fields, in the presence of tissue-specific scaffolding or in highly precise flow or tension environments. The disciplines of biology, physics, and engineering are combined in this new field of tissue engineering (TE). Successful TCE have been used to treat bone disease, replace cartilage and tendons and to repair fascia in hernias. Though there are still many technical problems that must be solved, one of the ultimate goals of TE is to engineer entire organs and to implant them in patients to replace diseased tissues.
Military interest in ETC focuses on using engineered tissue to study and perhaps cure diseases associated with bioterrorism threats. For example, the development of organs that simulate the immune system provide an excellent clinical model on which new vaccines that provide better defense against bioterrorism agents may be tested. Alternatively, artificially engineered lymph nodes or other organs of the immune system could eventually be implanted in humans, inducing a powerful immune response against such biological agents as anthrax, plague, smallpox and other viruses.
In 2002, the Defense Advance Research Projects Agency (DARPA) announced an Engineered Tissue Constructs Program providing funding to research and private institutions to study ETC. The project has two stages. The first is to demonstrate that stem cells can be differentiated into a variety of different types of immune cells within a three-dimensional tissue construct. Funds for this stage have already been awarded. The second stage is a continuation of the first in which successful tissue engineered constructs are validated for appropriate immune responses.
█ FURTHER READING:
Lanza, Robert P., Robert Langer, and Joseph P. Vacanti. Principles of Tissue Engineering. Academic Press, 2000.
Defense Advanced Research Projects Agency, Defense Sciences Office < http://www.darpa.mil/dso/thrust/biosci/etc.htm. > (March 3, 2003).
Aastrom Biosciences, Inc., 24 Frank Lloyd Wright Drive, Ann Arbor, MI 48105. < http://www.aastrom.com. > (March 3, 2003).
Sciperio, Inc., 5202–2 N. Richmond Hill Road, Stillwater, OK 74075. < http://www.sciperio.com/bio.html > (March 3, 2003).
The Regional Medical Physics Department of the United Kingdom's National Health Service. "Tissue Engineered Synthetic Scaffolds." < http://www.rmpd.org.uk/research/bioengineering/tissue_engineered_synthet c_scaffolds.htm > (March 3, 2003).