- NEW YORK (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.
- SOURCE: Nature Biotechnology 2000;18:20-21, 43-47.