Delayed micrograft transplantation
The number and length of sessions a patient has to undergo
to complete a hair transplant procedure depends largely on the
hair density and proportionally the time involved in the process
of dissection and insertion of the grafts. After the donor hair
has been harvested, the patient has to wait a couple of hours
before the follicular units are separated and the recipient site
can be readied. In order to minimize the time delay, there are
proposals from several surgeons to preserve donor hair using various
techniques until the required number of follicular units can be
readied and the transplantation performed in a single session.
One of the first proposals based on this idea was suggested by Kurata et al.
in 1999. They tried to preserve the dissected hair follicles in a salt solution
called DMEM at 4 deg C at varying lengths of time after which they were transplanted
on the skin of athymic mice to evaluate the success of their technique. According
to their observations, hair follicles were cultivatable for up to 7 days after
excision and 60% of the transplanted hair in mice grew well even after 5 months
post implantation. With this as background, Qian et al. from Institute of
Dermatology, Peking Union Medical College and Chinese Academy of Medical Sciences,
China have conducted further experiments in an attempt to identify better
hair follicle preservation techniques.
Qian and colleagues harvested hair follicles from patients who
had undergone face lift procedures and follicular units containing
1-2 hairs were only selected and preserved in Ringer’s and
DMEM solution at 0 deg C for 24 h, 48 h, 3 days and 7 days respectively.
Lactated Ringer’s solution, also known as Hartmann’s
solution, is generally used for intravenous administration. It
is a rich source of sodium, chloride, potassium and calcium ions
obtained by combining sodium chloride, calcium chloride, potassium
chloride and sodium lactate. DMEM or Dulbecco/Vogt modified Eagle’s
minimal essential medium is a cell culture medium suitable for
most types of animal cells including human, monkey, rat, hamster
and chicken cells. It contains amino acids, vitamins such as ascorbic
acid, folic acid, nicotinamide, riboflavin and B 12 along with
glucose, salts and extra iron.
The hair follicles were pretreated with 0.3% trypsin for 3 mins
and all extra connective tissue was removed. The follicles were
then cultured in Petri dishes coated with gelatin and nurtured
with DMEM and 10% FCS as a supplement and incubated at 37 deg
C for 7 days in a CO2 water jacketed incubator with 5% CO2 and
95% air atmosphere. Using an inverted microscope, the cultures
were studied for possible hair colony formation. Results from
this experiment revealed that colonization of hair follicles decreased
with increase in preservation time. That is hair follicles preserved
for 24 h had better potential to form colonies as compared to
follicles preserved for 48 h, 3 days and 7 days. The outer sheath
cells also showed better growth with follicles preserved for 24
h. At this preservation time about 95.8% growth of outer sheath
cells were seen in Ringer’s solution while about 86.7% in
DMEM. With increase in preservation time, the rate of growth of
outer sheath cells decreased but, the rate of growth in Ringer’s
solution was significantly higher as compared to DMEM in all the
experiment’s time frames. This formed the cell culture part
of the experiment.
Another set of hair follicles preserved in DMEM and Ringer’s
solution at 0 deg C were transplanted under the skin in a layer
called the panniculus carnosus of 24, four-week old athymic mice.
While two of the experimental animals died within a few days of
transplantation the rest of them were allowed to grow for 5 months
after which they were killed and the growth characteristics of
the hair follicles studied. As compared to cell culture results,
the hair survival rate in the mice seemed a little less with 84.8%
in Ringer’s and 72.5% in DMEM when 24h treated hairs were
transplanted. Those follicles with 48h and 3 days exposure to
preservation showed a drastic decrease in survival rates and those
of 7 days had practically no growth. Those hairs that re-grew
were very thin as opposed to the normal hair thickness and the
length ranged from 15-26 mm.
From these sets of experiments, it could be concluded that for
long term preservation of hair follicles, the solutions maintained
at 0 deg c are better than those at a temperature range of 1-4
deg C. Since the hair transplant was in the panniculus carsosus
area and not on the skin as performed by Kurata et al., the possibility
of follicle damage by mechanical means was nil. Since no specific
solution or combination has been identified for hair preservation
and culturing, the regularly used Ringer’s and DMEM solutions
were made use of here. Despite DMEM being richer in all aspects
in comparison with Ringer’s, the latter has been found to
give better results. In accordance with the results, the authors
have suggested that preserved hair follicles no more than 48 h
of preservation is good for transplantation with those preserved
for a maximum of 24 h giving the best results.
Delayed micrograft transplantation references
- Qian JG, Li WZ, Zhang GC, Yan LB.
Is delayed micro-graft hair transplantation possible?--evaluation of viabilities
of hair follicles preserved in two storage media. Br J Plast Surg. 2005 Jan;58(1):38-41.