Posted by Johan Department of Biological Sciences, University of Durham, UK The dermal sheath that surrounds the outside of the hair follicle contains PMID: 11705511 [PubMed - in process] ---------------------------------------------------------------------------- Department of Biological Sciences, University of Durham, Durham, UK. Successful hair follicle organ culture has been established for some time, PMID: 11564165 [PubMed - indexed for MEDLINE] ---------------------------------------------------------------------------- Department of Biological Sciences, University of Durham, South Road, A series of experimental bioassays has shown that the dermal papilla of the
on 12/14/2001, 1:32 pm
Lancet 2001 Oct 27;358(9291):1445-8 Hair follicle dermal sheath cells:
unsung participants in wound healing. Jahoda CA, Reynolds AJ.
progenitor cells that maintain and regenerate the dermal papilla, a key
component for hair growth. Our contention is that dermal sheath cells have
other roles. We believe that they can become wound healing fibroblasts and
perform an important function in the repair of skin dermis after injury.
The dermal sheath has close developmental and anatomical parallels with
follicle outer root sheath, the epithelial component that contains the stem
cells responsible for replacing skin epidermis. Dermal sheath cells also
have a myofibroblast or wound healing phenotype, and in animals with high
follicle densities differences in wound healing are observed in conjunction
with changes in the hair growth cycle. Similarly, in human beings there are
apparent differences in wound healing responses between hairy and non-hairy
body sites. Moreover, clinical and experimental data suggest that the
involvement of follicle-derived dermal cells results in qualitatively
improved dermal repair. Therefore, in a therapeutic context, hair follicle
dermal cells provide an accessible option for the creation of dermal or
full skin equivalents that could both improve wound healing and reduce
scarring. Indeed, given the inductive properties of adult hair follicle
dermal cells, it is reasonable to envisage a tissue engineering approach
for the production of a skin equivalent that will grow hair follicles when
grafted.
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J Invest Dermatol 2001 Sep;117(3):596-604 In vivo induction of hair growth
by dermal cells isolated from hair follicles after extended organ culture.
Robinson M, Reynolds AJ, Gharzi A, Jahoda CA.
but hair growth in vitro is limited and generally terminates prematurely in
comparison with in vivo. The reasons why growth stops in culture are as yet
unknown. In this investigation, adult rat vibrissa follicles for which
growth in culture is limited to about 10 d, were maintained in vitro for a
minimum of 20 d after the hair shaft stopped growing. The pattern of fiber
growth and long-term follicle pathology reflected the initial hair cycle
stage at the time of isolation. Furthermore, there was evidence that a
group of follicles put into culture when in late anagen were attempting to
cycle in vitro. Microscopy showed that, in spite of widespread pathologic
changes to the follicle epithelium, dermal cells in the follicle showed
remarkable resilience. Their viability was confirmed when primary cell
cultures were established from isolated dermal tissue. These cells labeled
positively for alpha-smooth muscle actin, an established marker of hair
follicle dermal cell phenotype in vitro. Moreover, isolated dermal tissue
induced hair growth when implanted into inactivated hair follicles in vivo.
These data confirm that the cessation in hair growth is not due to a loss
of the inductive capacity in the dermal component. Long-term organ culture
may provide opportunities to investigate factors that are expressed or lost
during hair growth cessation. In addition it may be possible to develop
this method further to obtain a reliable and predictable model of hair
follicle cycling in vitro.
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Exp Dermatol 2001 Aug;10(4):229-37 Trans-species hair growth induction by
human hair follicle dermal papillae. Jahoda CA, Oliver RF, Reynolds AJ,
Forrester JC, Gillespie JW, Cserhalmi-Friedman PB, Christiano AM, Horne KA.
Durham, DH1 3LE, UK. Colin.Jahoda@durham.ac.uk
adult rodent vibrissa hair follicle retains unique inductive properties. In
view of the many phenotypic and functional differences between specific
hair follicle types, and the growing interest in hair follicle biology and
disease, it remains important to establish that the human hair follicle
dermal papilla has equivalent capabilities. In this study we tested the
ability of human hair follicle papillae to induce hair growth when
implanted into transected, athymic mouse vibrissa follicles. The implanted
papillae that interacted with mouse follicle epithelium created new
fibre-producing follicle end bulbs. The origin of the papillae in the
recombinant structures was confirmed using laser capture microdissection
and human specific gender determination by PCR. The demonstration that
intact adult human dermal papillae can induce hair growth has implications
for molecular analysis of basic hair growth mechanisms, particularly since
the study involved common epithelial-mesenchymal signalling and recognition
properties across species. It also improves the prospects for a cell-based
clinical approach to hair follicle disorders.
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