Dr George Cotsarelis and colleagues at the University of Pennsylvania
in Philadelphia have successfully incorporated genes into normal
growing hair follicles. They recently reported that successful
transfection of human hair follicles using topical liposomes
is optimal at the onset of anagen. This study was first
presented at the Society for Investigative Dermatology annual
conference in Chicago, May 1999.
Previously it was shown that topical liposomes could be used
to transfer DNA to mouse hair follicles, but this is the first
time that DNA has been successfully transferred to human hair
follicles. Liposomes are very small, submicroscopic globules
of oil. The liposomes are able to penetrate through skin very
easily and they can act as carriers to take drugs, proteins,
or even DNA into the skin.
Hair follicles include very active, rapidly dividing cells.
These cells are continuously replicating their own DNA for inclusion
in new cells. This means that hair follicle cells are very receptive
to incorporation of new DNA. Potentially it should be quite
easy to transfer a gene through the skin to hair follicles using
liposomes. The liposomes penetrate the skin and then fuse with
the walls of cells and release their DNA contents into the cells.
The DNA is then included in new DNA made for new hair follicle
cells. Dr Cotsarelis took advantage of this phenomenon and transferred
a beta galactosidase reporter plasmid into human hair follicles.
This plasmid contains the DNA code for a gene that makes a blue
Although this gene has no use in treating hair loss, Dr Cotsarelis
and friends say the technique could be turned to growing hair
someday. Dr. George Cotsarelis, director of the Hair and Scalp
Clinic at the University, said in a statement. These early
results in our ongoing research suggest that certain types of
hair loss might be suitable for gene therapy, The idea
behind this kind of gene therapy is to use genetic material
to replace a faulty gene, or to boost the efforts of genes normally
active in hair follicles.
The research team found that they incorporated DNA most successfully
into hair follicles when the follicles were in the very early
stages of anagen growth. The research team believe this technique
could be used in such diseases as alopecia areata where many
hair follicles are in an early dystrophic anagen stage of growth.
It could also be used in androgenetic alopecia where many hair
follicles are in telogen. These inactive telogen hair follicles
could be induced into an early anagen and then have a gene therapy
applied to promote full terminal hair regrowth.
The research shows that gene therapy could be very effective
in treating many forms of hair loss where genes are involved.
The gene application using liposomes could be used to replace
faulty genes that cause hereditary hair loss. The treatment
techniques may also be used to reactivate switched off, normal,
healthy genes and encourage hair growth after hair loss caused
by environmental factors as can occur in telogen effluvium.
The technique could even be used to block the activity of unwanted
genes such as those involved in 5 alpha reductase activity.
5 alpha reductase is the enzyme that converts testosterone to
dihydrotestosterone. However, the biggest challenge is to identify
suitable genes that can be used as an effective treatment for
Unless the hair follicle stem cells are successfully transfected
with the desired genes, the treatment will have to be regularly
re-applied to have a continued effect. Cells die off rapidly in
hair follicles. Most are incorporated into the growing hair fiber.
This means that the transferred gene can be lost. In the research
presented Dr Cotsarelis and company, they found the gene they
transfected disappeared from hair follicles after a month or two.
It may prove to be very difficult to transfect the stem cells
(the true source of all the cells made in hair follicles) and
make gene therapy a single application and permanent cure for
hair loss diseases.