Article written exclusively for HairlossTalk and its users, Dr. Kevin McElwee provides this three-part review on the current state of hair cloning research, its history, and what you can expect to see in the coming years with this exciting new technology...
The hair follicles we are born with have to last us a lifetime. Like internal
organs, we cannot naturally generate new hair follicles in adult life. If hair
follicles are damaged or destroyed through disease or trauma, the area of affected
skin is permanently depleted of hair follicles. At least that is currently the
case, but in the same way that research is being conducted into the possibility
of organ regeneration to replace, for example, a diseased liver, scientists have
been looking at ways to regenerate hair follicles.
How Hair Cloning Works
In principle, it is possible to produce new hair follicles from certain
cells. At its simplest, a few healthy hair follicles can be excised from an individual
by biopsy. The follicles are then dissected to isolate a small ball of cells at
the base of each follicle called the dermal papilla. For the average full grown
scalp hair there are about 200-400 cells in each dermal papilla. That’s
not much, but these cells can be cultured in incubators to make several hundred
thousand cells within about 6 weeks or so. These cells can then be implanted into
bald skin where the dermal papilla cells induce new hair follicles to develop.
The process is not fully understood, but we do know that dermal papilla cells
send out chemical signals called cytokines that tell the skin to produce a new
hair follicle. A new hair follicle is made from epithelial cells, but the *development
and cycling* of the follicle is determined by dermal papilla cells. You must have
both dermal papilla cells and epithelial cells together to form a hair follicle.
Just one or the other cannot form a follicle on their own.
Re-triggering that Fetal Fun...
This process whereby dermal cells communicate with epithelial cells to produce
hair follicles occurs naturally during your fetal development. At this time, cells
destined to become dermal papilla cells, migrate through the skin dermis and start
to cluster together. The initial trigger that causes this to happen is unknown.
Each cell cluster is tells nearby epithelial cells to make a new hair follicle,
but after birth the number and distribution of dermal papilla cell structures
are all fixed in place. There is no new dermal papilla structure formation, so
there is no new hair follicle formation after birth. However, the above principle
shows that all the ingredients necessary to generate brand new follicles *are*
present in adult skin. The kicker is trying to figure out how to get these cells
to restart their communications and do what they did while you were an adorable
little fetus.
A topical Hair Cloning treatment?
It might be possible one day to cause new hair follicle formation by applying
skin with a chemical signal that triggers the resident dermal cells to return
to their embryogenic days, but such a treatment approach is not likely for a long
time. We know some of the chemical signals that might be involved, but certainly
not all of them. Products such as Lef1 or beta Catenin may be involved, but there
must be many more factors involved to induce hair follicle development that we
do not know about. Before a chemical treatment can be developed to induce new
hair follicle formation, we need to know a lot more about the mechanism of natural
hair follicle development.
Since we don't yet have a convenient topical liquid you can just put on your head
to kickstart new follicle development, several academic and commercial groups
based in the US, Canada, England, the Netherlands, and Japan have been looking
into the method of extracting normal hair follicles, culturing the dermal papilla
cells outside the body, and then implanting them, to induce new hair follicles.
This basic technique comes in several variations and with a variety of names,
but perhaps the most common method of referring to the hair follicle regeneration
principle is “hair or follicle cloning”. Strictly speaking, the technique
does not involve cloning in the true scientific sense (as in Dolly the sheep),
but multiple hair follicles can be produced from just one donor follicle, so it
is a sort of cloning. Others refer to “follicular neogenesis” or “multiplication”.
It is all basically the same thing.
Hair Cloning is a proven Technology
Scientists have actually known about the ability to induce new hair follicle
development by using existing hair follicles for a long time. As far back as
1944 two scientists, Lillie and Wang, were taking bits of feather follicle (which
is basically the same structure as a mammal hair follicle) and implanting them
to chicken skin to induce new hair follicles to form. In the 1960's Cohen and
Oliver showed the same could be done with rat follicles. This principle was
developed greatly by other scientists and particularly Colin Jahoda and Amanda
Reynolds who are past students of Oliver. With studies on rodents, Jahoda and
Reynolds showed that just the dermal papilla cells could be used to produce
new hair follicles, and that these cells could be cultured and then transferred
to skin to induce new hair follicles. In a paper published in the top journal
“Nature”, they showed that cells could be taken from one human donor,
(Jahoda) and implanted to another (Reynolds) and induce new hair follicle formation,
although no cell culturing was involved in this particular study. So far this
is the only study actually published to prove hair cloning would work in humans.
Continue to Part 2 of this article...
(More interesting than Part 1 - Part 2 addresses the reasons why hair cloning isn't currently working, and talks about the latest research findings)
