As early as 2002, the Defense Advanced Research Projects Agency put out a request for proposals seeking novel ideas giving troops a technology to immediately accelerate tissue repair for wounded or injured soldiers. Ideas suggested in the proposal included use of electromagnetic fields such as near infrared, millimeter waves and radio frequency.
But now researchers say an evolutionarily conserved gene called Lin28a, active in embryos but not in adults, enhanced the repair of damaged tissue in a test using mice. By reactivating the dormant gene Lin28a, which is active in embryonic stem cells, researchers were able to regrow hair and repair cartilage, bone, skin and other soft tissues in mice, Boston Children’s Hospital said in a Nov. 7 statement.
"It sounds like science fiction, but Lin28a could be part of a healing cocktail that gives adults the superior tissue repair seen in juvenile animals," lead researcher Dr. George Daley, director of the hospital’s Stem Cell Transplantation Program, said in a Nov. 7 statement. The findings were published that day in the journal Cell.
To date, the testing proved successful in young mice, but not adults, and so there is still a ways to go, researchers said.
Past efforts to improve wound healing and tissue repair have mostly failed, but altering metabolism is a new strategy that could prove successful, Daley said. The researchers determined that the Lin28a protein could play a role because it regulates growth and development in juveniles, though its levels decline with age.
Scientist Shyh-Chang Ng, one of the authors on the journal paper, said it’s naturally assumed that cells related to growth are the major players in wound healing, “but we found that the core metabolism of cells is rate-limiting in terms of tissue repair. The enhanced metabolic rate we saw when we reactivated Lin28a is typical of embryos during their rapid growth phase."
They reactivated the protein in the mice, whose bodies where shaved of hair and their ears and digits injured. The result was a spurring of production of metabolic enzymes and processes normally more active in embryos – essentially “revving up” cell bioenergetics to generate the energy needed to stimulate and grow new tissues, they said.
Further experiments showed they could enhance wound healing with manufactured compounds that directly activated mitochondrial metabolism, rather than Lin28a, which is difficult to get into the cells.
This possibly opens the door to tissue regeneration repair with drugs, they said.