NEW YORK, Jan 05 (Reuters Health) -- It won't be on the drugstore shelf
any time soon, but a type of gene therapy called gene repair could one day
replace coloring as a way to cover up gray hair, US researchers suggest.
According to a report in the January issue of Nature Biotechnology,
altering a mutation in a gene in the hair follicle restored pigmentation to the
hairs of albino mice. The study is the first to demonstrate that genetic
manipulation can correct a damaged gene sequence in the hair follicle, the
authors write.
"Gene therapy has just taken a cosmetic step forward," Robert M. Hoffman,
president of AntiCancer, Inc., a San Diego, California-based biotechnology
company that develops products to diagnose and treat cancer, stated in an
editorial.
While the study results suggest that certain molecules made up of a
corrective DNA sequence may help to restore pigmentation in mice, similar
studies have not been conducted on humans, according to the research team from
Thomas Jefferson University and Jefferson Medical College and the University of
Pennsylvania in Philadelphia.
Kyonggeun Yoon, an associate professor in the department of dermatology
and cutaneous biology at Jefferson Medical College, and one of the study's
authors, explained the technique. "The albino mouse has a mutation in
tyrosinase, a key enzyme involved in melanin synthesis. Graying hairs are caused
by loss of melanocytes due to the aging process," Yoon told Reuters Health.
The investigators applied molecules, known as chimeric oligonucleotides,
to albino mice that had had their hair removed. The molecules were applied
topically to 4 mice and or injected into the skin of 11 mice.
A few weeks after treatment, a small number of pigmented hairs grew in the
areas that were exposed to the oligonucleotides. Tests revealed that a key DNA
sequence had been repaired and key enzyme activity had been restored, although
the mechanism of gene correction has not been shown, Yoon said.
Color was found in only a small number of hairs and lasted just 3 months
after the last application, however. The authors explain that enhancing DNA
delivery to the hair follicle, correcting the mutation in the correct stage of
hair growth cycle or correcting stem cells in the skin, could lead to more
permanent results.
The researchers had previously shown that gene repair could be used to
restore the pigmentation of albino cultured mouse skin cells by correcting a
mutation in the enzyme responsible for producing the pigment melanin.
In his editorial, Hoffman notes that the study offers "exciting
possibilities... for modifying hair features." The hair follicle "stands as one
of the most promising targets for effective, useful, safe and lucrative gene
therapy," he adds.
