IDOASIS said:
docj077 said:
TGF-beta may be an immune regulatory molecule, but that does not mean that every person has immune response during male pattern baldness. Not every person has infiltrates of lymphocytes and leukocytes to the area of the follicle.
No immune response is required and an immune response is rarely seen unless the it's secondary to bacteria breaking down secretions from the sebaceous glands into proinflammatory fatty acids. This doesn't happen in every person, so there isn't an immune response.
Can you prove it? ,please link me to a study.
Study is demonstrated below with no histological mention of lymphocytic infiltrates during histological examination of male pattern baldness follicles.
docj077 said:
Alopecia areata is considered to be an autoimmune disorder and androgenic alopecia is a hormonally-linked disease that results in fibrotic response. They are not similiar in any way except for that they cause a similar result.
docj077 said:
TGF-beta may be an immune regulatory molecule, but that does not mean that every person has immune response during male pattern baldness.
You are not consistent ,you say there is no link between AA and male pattern baldness,
then you say there can be with some of us.
Nope, that's not what I said at all. Re-read it. An immune system response and an immune regulatory molecule are not the same thing. Anyone that has taken immunology can tell you that.
docj077 said:
Lastly, please post studies, not mere rantings from a random website. If that is actually from Dr. Proctor, then it's taken out of context as that's not what his entire theory encompasses.
IT IS ALL from PUBMED.
http://www.ncbi.nlm.nih.gov/entrez/quer ... med_docsum
http://www.ncbi.nlm.nih.gov/entrez/quer ... t=Abstract
So far I have not seen one study from you.
As I said, learn the difference between alopecia areata and alopecia androgenica. Your study is dealing with alopecia areata, so you really have no argument.
Notice that inflammation is mentioned, but not in the context of an immune response (i.e. macrophages, neutrophils, lymphocytes, etc. being present). Also notice, that their is no mention of alopecia areata being synonymous with alopecia androgenica.
It is also important to notice that they induced the TGF-beta response using only testosterone and not DHT, which is something that I've pointed out in the past. All androgens affect the hair follicle unit and simply inhibiting DHT in any fashion will not suffice to prevent male pattern baldness as testosterone causes the exact same mechanism.
Perifollicular Fibrosis: Pathogenetic Role in Androgenetic Alopecia
Hyeon Gyeong YOO, Jin Sook KIM, Se Rah LEE, Hyun Keol PYO, Hyung In MOON,
Jong Hee LEE, Oh Sang KWON, Jin Ho CHUNG, Kyu Han KIM, Hee Chul EUN, and
Kwang Hyun CHO*
Department of Dermatology, Seoul National University College of Medicine, Laboratory of Cutaneous Aging and Hair
Research, Clinical Research Institute, Seoul National University Hospital, and Institute of Dermatological Science, Seoul
National University; Seoul, 110–744, Korea.
Received October 12, 2005; accepted December 13,
On close histological observation of balded scalp biopsies,
the miniaturization of terminal hairs is a distinguishing feature
in Androgenetic Alopecia and is frequently associated with perifollicular
fibrosis.5,6) The miniaturization of the hair follicles was found
to be associated with a deposit of so-called “collagen or connective
tissue streamers†beneath the follicle7) as well as a
2—2.5 times enlargement of the follicular dermal sheath
composed of densely packed collagen bundles.5) Transforming
growth factor-beta 1 (TGF- b1) has been proposed to play
an important role in catagen regulation. TGF- b1 has a negative
growth-regulatory effect on hair follicles in vitro.8)
Androgenetic Alopecia is hereditary and androgen-dependent, progressive
thinning of the scalp hair that follows a defined clinical pattern.
Major advances have been achieved in finding out the
androgen metabolism involved. Until now, it can be summarized
into just two points. One is more peripheral conversion
of T to DHT, a reaction catalyzed by the enzyme 5a-R in
hair follicles from the balded scalp.10) Type II 5a-R transforms
T into DHT and does so more in the areas of the scalp
affected by Androgenetic Alopecia than in those in which Androgenetic Alopecia never develops.
Compared to T, DHT has approximately five fold greater
affinity for the AR and DHT binding to AR in hair follicles is
commonly accepted as the first step leading to the miniaturizing
of follicles seen in Androgenetic Alopecia.11—13) The other is higher levels
of AR in cells from balding scalp hair follicles with similar
properties to those from non-balding scalp.14)
The primary location for the AR in hair follicles is well
known to be the dermal papillae in both anagen and telogen
hairs.15,16) Moreover, it is usually believed that the dermal
papilla plays a major regulatory role in hair follicles and is
thought to be the site of androgen action. Therefore, action
mechanisms of androgen on Androgenetic Alopecia has been usually studied
using dermal papilla cells.14,17—21)
Recently, AR has been also identified in the interfollicular
DFs and epidermal keratinocytes.15) Recently, AR has been also identified in the interfollicular
DFs and epidermal keratinocytes.15) Therefore, several efforts to explain the pathogenetic mechanism of Androgenetic Alopecia had
been made in hair epithelial cells as well as DPC.17,18,21—23)
Previous reports showed that the DHT and T treatment
elicited an increase in the steady state concentration of
a1(I)-procollagen mRNA in human osteoblast-like osteosarcoma
cells24) and that collagen synthesis was stimulated by androgen in mice.25)
For that reason, perifollicular fibrosis
may be another pathogenetic mechanisms of Androgenetic Alopecia, not a
simple phenomenon usually seen in Androgenetic Alopecia.
This study clearly demonstrated that T stimulated the transcription
and protein expression of type I procollagen gene in
follicular DFs much more than vehicle-treated controls.
This
suggests that type I procollagen synthesis induction by androgen
(T) may be, in part, responsible for densely packed
collagen bundles around miniaturized hair follicles leading to
perifollicular fibrosis seen in Androgenetic Alopecia. Finasteride treatment can
also alleviate androgen-induced transcription and protein expression
of type I procollagen in the follicular DFs. When a
hair follicle miniaturizes, it ascends upward from the reticular
dermis to the papillary dermis, followed by an associated
angiofibrotic tract called a follicular streamer.26) Considering
above results and other report, the miniaturized hair can
travel back down the streamer tract to the reticular dermis to
resume its position and role as a terminal hair with finasteride
treatment. These results ascertained as a basic mechanisms
of finasteride to improve Androgenetic Alopecia in the aspect of DFs.
The type II 5 a-R is crucially involved in the pathogenesis
of androgen-dependent hair growth. According to previous
study, both DPC and DFs from occipital scalp hair expressed
type I and II 5 a-R cDNA.11) The type II gene was transcribed
more in DFs than in DPC.11) Finasteride is well known as a
potent and highly selective 5 a-R type-II inhibitor.12,13) It is
reasonable that the action mechanisms of finasteride on Androgenetic Alopecia
can be explained as inhibition of collagen synthesis in the
follicular DFs, which lessens perifollicular fibrosis and formation
of angiofibrotic tract involved in catagen induction.
TGF- b1 appears to inhibit the rate of hair follicle lengthening
in vitro and in vivo in mice to promote the regression
phase of the organ culture of human hair follicles.8) Thus,
TGF- b1 is considered as a catagen induction marker in hair
follicle.9) TGF- b1 was shown to induce a rapid fibrotic response
in vivo.27,28)
Moreover, chronic expression of TGF- b1
in adult DFs caused severe alopecia characterized by epidermal
and follicular hyperproliferation, apoptosis, as well as
dermal fibrosis and inflammation.29) Inui et al.23) demonstrated
that androgen induced TGF- b1 from the balding dermal
papilla cells plays an important role in miniaturization of
hair shaft. Also, a key function for TGF- b in wound healing
and fibrosis is to regulate the expression of proteins of the
fibrillar collagens and fibronectin. TGF- b is considered a potent
anabolic factor that enhances connective tissue deposition
and repair and which sustained signaling likely leads to
the development of tissue fibrosis.30) Therefore, it can be inferred
that the T-induced TGF- b1 expression may induce
perifollicular fibrosis in the DFs, accelerate hair follicles into
moving on catagen phase of hair cycle, and inhibit epithelial
growth, which brings all together out miniaturization of hair
follicles in Androgenetic Alopecia. According to pretreatment of neutralizing
TGF- b1 antibody, T-induced type I procollagen level may decreased
through the anti-TGF- b1 protein in the DFs. This result
was related to TGF- b1, which induce catagen period fi-
brosis as the epitome of T-induced Androgenetic Alopecia. In this study, the fi-
nasteride and T co-treatment was demonstrated to reduce the
expression of TGF- b1 in scalp follicular DFs. This result
also explains another possible action mechanisms of finasteride
on Androgenetic Alopecia.
It is very difficult to obtain in vivo human scalp follicular
cells. The scalp biopsies at the vertex and occiput in each
person are much more difficult because of few volunteering.
For that reason, the main limitation of this study is that it can
not compare the results in vertex and occipital scalp follicular
DFs. Although this study could not be performed under
the comparative design, it still has valuable meanings that the
vertex scalp follicular DFs have the active receptors response
to androgen hormones and androgen hormone has effects on
production of the collagen from follicular DFs, which shows
histopathologically characteristic perifollicular fibrosis in
Androgenetic Alopecia. In conclusion, perifollicular fibrosis induced by androgen
can be suggested as one of the underlying pathogenetic
mechanisms, resulting in hair follicle miniaturization in
Androgenetic Alopecia. The biological characteristics of finasteride may be
also explained as reducing T-induced procollagen and TGFb1
synthesis, diminishing perifollicular fibrosis in Androgenetic Alopecia.