Combining gene therapy plus an infusion of stem cells helps heal wounds faster in mice, a discovery that could eventually lead to better treatments for older people with wounds, who fail to heal as well as younger patients.
"As we get older, it is harder for our wounds to heal," says researcher Dr. John Harmon, a professor of surgery at the Johns Hopkins University School of Medicine. "Our research suggests there may be a way to remedy that." Harmon presented his findings to the American College of Surgeons' Surgical Biology Club this week.
Stem cells from the bone marrow are vital to the healing process in humans. A specific protein, called hypoxia-inducible factor-1 (HIF-1), is what kicks these stems cells into gear, releasing them from the bone marrow and to the wound, where they can become blood vessels, skin and other reparative tissue. Older people have lower levels of HIF-1, though, and fewer stem cells are released from the bone marrow to aid in healing, Harmon says.
First, Harmon and his team tried using gene therapy alone to speed up the healing process in elderly mice with diabetic wounds. They injected mice with a better working copy of the gene that codes for the HIF-1 protein but had little success. They next tried enhancing the outcomes of gene therapy with stem cells. Using bone marrow from a young mouse, the researchers grew stem cells in the lab and then injected those supercharged cells back into the mice.
When investigators checked in on the mice after 17 days, they observed that mice that were treated with the combination therapy had more completely healed wounds than in the other groups. The mice treated with the combo therapy also showed better blood flow and more blood vessels supplying the wounds.
Meanwhile, another team of Johns Hopkins researchers has found a type of stem cell in fat cells and also in bone marrow that promotes nerve regeneration in rats.
The findings of both studies point to promising new stem cell therapies that use a patient's own cells, which are less likely to be rejected by the body than cells from someone else. Plus, HIF-1 gene therapy has been safely used in humans to treat sudden lack of blood flow to a limb.
- here's the press release