|
What
is hair cloning by bisection
Some dermatologists are touting "hair cloning" as the future of
hair transplantation, but few people actually know what it is.
At its most basic, hair cloning involves taking one hair follicle
from a donor and multiplying it in a laboratory to make several
hair
follicles. There are two main forms of hair cloning under development
for use in the transplant clinic, both of which have already been
used experimentally on humans. One involves purely surgical techniques
the other involves cell culture. Here, the surgical technique is
explained.
 |
|
human
hair follicle isolated by dissection ready for further
experiments
|
Hair cloning by multiplication involves taking a hair follicle by
standard hair transplant surgery techniques and then cutting the
hair into two (and maybe more) pieces. So if a typical hair transplant
involves implanting 3000 hair follicles, by bisecting the hair follicles
into two and implnating the upper hair follicles and the lower hair
follicle portions seperately, you could get 6000 hair follicles growing
while only 3000 hair follicles were taken fro mthe donor skin area.
To get this method of hair cloning to work, a technician must have
a fine eye, steady hands, and good micro dissection equipment. It
is very easy to cut the hair follicle in such a way that it does
not have enough cells to be able to regenerate. Hair follicles can
be quite sensitive once they are isolated from the skin so any surgical
manipulation can severely damage them. The technician has to have
considerable experience in dividing the hair follicles with the minimum
of disruption to keep them viable.
For a hair follicle cloned in this way to be viable as a transplant,
it must contain dermal papilla cells or cells capable of regenerating
a dermal papilla, and keratinocytes that make hair fiber. Animal
research has shown that for a single hair follicle to be made into
two hair follicles, the original hair follicle must be dissected
such that the cut only removes the lower one third of the hair
follicle. If this is done correctly and the upper and lower parts
of the follicle are implanted into skin, then the upper two thirds
of the hair follicle will regenerate a brand new hair bulb and
the lower third of the hair follicle will regenerate the missing
upper two thirds of the hair follicle. However, if the hair follicle
is cut so that the upper portion of the hair follicle has less
than two thirds of the tissue remaining and the lower hair follicle
gets more than a third of the tissue, the lower hair follicle piece
will grow, but the upper hair follicle piece is no longer able
to regenerate a new hair bulb. So, if the hair follicles are not
bisected correctly, you may end up with no "new" hair
follicles to implant.
Even if the hair follicles are correctly dissected, there are
still several potential problems with the results of the technique
that need to be overcome before the method can be made routinely
available. For example, the thickness of the hair fiber produced
by a hair follicle is directly proportional to the size of the
dermal papilla and number of cells contained in it. By cutting
a donor hair follicle in two or more parts the effective number
of cells and size of dermal papilla might be reduced. After transplantation
it is possible that the hair produced by the clones is much finer
than the hair produced by the original hair follicle. However,
some transplant sepcialists have suggested that these fine hairs
can put to good use to create finer hair lines (Swinehart 2001).
So while hair multiplication may not be good for filling large
bald areas of skin, they could be good for creating more natural
hairlines.
What
is hair cloning by bisection
- Swinehart
JM. "Cloned" hairlines: the use of bisected hair follicles
to create finer hairlines. Dermatol Surg. 2001 Oct;27(10):868-72.
PMID: 11722523
- Elliott
K, Stephenson TJ, Messenger AG. Differences in hair follicle
dermal papilla volume are due to extracellular matrix volume
and cell number: implications for the control of hair follicle
size and androgen responses. J Invest Dermatol. 1999 Dec;113(6):873-7.
PMID: 10594724
- Raposio
E, Filippi F, Levi G, Nordstrom RE, Santi P. Follicular bisection
in hair transplantation surgery: an in vitro model. Plast Reconstr
Surg. 1998 Jul;102(1):221-6. PMID: 9655431
- Stough D, Whitworth JM. Methodology of
follicular unit hair transplantation. Dermatol Clin. 1999 Apr;17(2):297-306,
viii. PMID: 10327299
|
