Transplanting human hair onto the backs of mice may lead to a break-through for baldness treatments, scientists said.

The researchers cloned cells in the scalp that give rise to hair follicles and transplanted them onto the backs of mice, growing new human hair for at least six weeks, according to a study released today in the Proceedings of the National Academy of Sciences. More work must be done before the method can be tried in humans.

Previous methods to curb balding have focused on slowing hair loss, stimulating dormant hair follicles, or transplanting hair from the back of the head to the front, which doesn’t increase the total amount of hair. Women, in particular, may benefit from treatments derived from this finding, since many women with hair loss don’t have enough donor hair for this kind of transplant, the researchers said.

Further research could “make hair transplantation available to individuals with a limited number of follicles, including those with female-pattern hair loss, scarring alopecia, and hair loss due to burns,” Angela M. Christiano, a professor of dermatology at the Columbia University Medical Center in New York, and one of the lead study authors, said in a statement.

The cells, called dermal papilla, are what generate hair follicles. Though it’s easy to clone and transplant mouse dermal papilla, the human versions of the cells don’t grow as well in culture. This may be because rodent dermal papilla form clusters naturally in culture. Taking a hint from the rodents, the scientists packed the human cells into clumps.

Hair Growth

After a few days, the cultured cells were transferred to patches of human skin on the mice’s backs. In five of the seven tests, hair grew for six weeks, the study found.

More work is needed before humans can be treated with this protocol, the researchers said. The new hair needs to be characterized, and things to be determined include the color, angle, positioning and texture of the newly created hair. In addition, the role of the host cells the hairs interact with need to be better-characterized.

“This study is an important step toward the goal of creating a replacement skin that contains hair follicles for use with, for example, burn patients,” said Colin Jahoda, the study’s other lead author and professor of stem cell sciences at Durham University, England, in a statement.