Objective: Current in vivo models of de novo hair growth and
regeneration used in the laboratory are arduous, unrealistic
and therefore unable to be translated to clinical practice.
We sought to improve on this by a technique that is simple,
reproducible and generates a cosmetically acceptable
appearance. Here we present a novel method in which a large
number of hair and sebaceous glands can be reliably grown
from a suspension of single cells within a matrix.
Methods: Multipotential cells were obtained from neonatal
mice using techniques from previously published work. The
cells were loaded onto a pre-shaped, pre-treated matrix. The
entire matrix, with cells loaded inside, was then grafted onto a
full thickness wound created on the dorsum of a nude mouse.
Hairs were observed for long-term growth and wound healing.
Samples of de novo hair at different stages were taken for
immunohistochemistry and PCR studies.
Results: De novo hair growing on the dorsum of a grafted
nude mouse can be seen as early as 11 days post operative.
We performed these experiments using various commercially
available and self-made biologic collagen based matrices.
Over 40 athymic nude mice have been grafted with the matrix
construct seeded with pigmented wild type multipotential
cells. Greater than 92% of mice successfully grew de novo
hair in an organized planar fashion. Immunohistochemical
studies of de novo hairs prove that hairs are real and contain
all layers of normal hair. We have followed 6 mice as they
continued to grow hair for over one year after grafting. The
hair was also tested by shaving and plucking to demonstrate
normal cycling and regeneration.
Conclusions: We have shown with high reproducibility
that cells can be grafted with the help of a scaffold-like
matrix to produce new hair in an organized and clinically
acceptable fashion. The matrix can be shaped as needed
such that this can be used for specific regions of alopecia.
Further, it is conceivable that rather than dependence on
autotransplantation, future hair restoration will be able to
use an unlimited supply of stem cells organized by a shaped