Wounded troops: DARPA project to regrow human tissue enters next phase

By Steve Hammons

Will U.S. troops who have had serious war injuries find new help from ongoing research to regrow damaged human tissue?

According to an announcement March 23, 2009, the U.S. Defense Advanced Research Projects Agency (DARPA) has extended its contract with a Massachusetts biotechnology company for a research program on the regeneration of muscle tissue lost or damaged by traumatic injury.

DARPA’s long-range goal is to discover and optimize the natural regenerative abilities of the human body to heal war injuries experienced by U.S. troops, including injuries involving bone, muscle, nerves and other soft tissue.

What about people who have had limbs amputated? Could whole hands, arms and legs be regrown, similar to the way salamanders and starfish regrow limbs?

RESEARCHERS PURSUE DISCOVERIES

The company involved in the contract, CellThera, is part of the Bioengineering Institute (BEI) of the Worcester Polytechnic Institute (WPI).

A WPI press release notes that DARPA awarded CellThera a one-year $570,000 contract for research into regenerating mammalian muscle tissue. The contract could be extended for a second year. WPI will be a subcontractor for part of the program.

DARPA funded the first phase of the tissue regeneration program beginning in 2006 in a joint effort between CellThera, WPI and associates at Tulane University, the press release stated.

In that phase, the research team was successful in reprogramming mouse and human skin cells to behave more like stem cells, and more able to begin regrowing tissue.

In the next phase of the project, researchers will attempt to “reprogram and engineer cells to replace damaged skeletal muscle and to restore the normal function of that muscle,” according to the WPI press release.

Raymond Page, PhD, serves as principal investigator for WPI's part of the research. Page is an assistant professor in BEI and WPI's Department of Biology and Biotechnology.

In the next phase, George Pins, PhD, associate professor of biomedical engineering at WPI, joins efforts of the project. Pins developed cell-delivery strategies relevant to the program’s goals. Raymond Dunn, MD, will lead another team in the new research phase. Dunn is professor of surgery and cell biology at the University of Massachusetts Medical School and chief of plastic and reconstructive surgery at UMass Memorial Medical Center.

WOUNDED WARRIORS AND BIOLOGY

Many U.S. troops have sustained serious injuries in the wars in Iraq and Afghanistan. These wounds include traumatic and surgical amputations of legs and arms, burns, severe head and face trauma and other significant damage to body tissues.

Although improved body armor has prevented many deaths, as a result many troops survived with injuries so severe that they would have died in earlier wars.

Improvised explosive devices (IEDs) – roadside or vehicle-borne bombs – have been particularly deadly and damaging.

The DARPA-sponsored research may lead to new discoveries and medical applications that can help these seriously injured troops.

Currently, scientists understand much of the biology about how certain creatures regenerate limbs and other tissue. When salamanders and newts lose a limb, they create new "progenitor cells," also called "precursor cells." These cells gather at the site of the injury, forming a "blastema."

The blastema continue to grow and specialize into cells that form the nerves, bones, cartilage, muscles and skin to create a new limb.

For mammals, this ability typically occurs only in the fetal stage. Yet, new research and bioengineering activities have made progress in learning more about these processes.

Will the research soon progress to applications directly to humans? Depending on the progress made studying the genetic, cellular, chemical and other factors involved, human research could begin some day.

If DARPA-funded investigations into this field lead to success in regrowing selected human tissue, or even entire limbs and organs, people and children around the world with injuries, diseases and other significant medical problems could benefit in ways we can hardly imagine.