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Androgenetic alopecia: new insights into the pathogenesis and mechanism of hair loss.

Sinclair R, Torkamani N, Jones L - F1000Res (2015)

Bottom Line: The hair follicle is a complete mini-organ that lends itself as a model for investigation of a variety of complex biological phenomena, including stem cell biology, organ regeneration and cloning.  The arrector pili muscle inserts into the hair follicle at the level of the bulge- the epithelial stem cell niche.  The arrector pili muscle has been previously thought to be merely a bystander and not to have an active role in hair disease.Computer generated 3D reconstructions of the arrector pili muscle have helped explain why women with androgenetic alopecia (AGA) experience diffuse hair loss rather than the patterned baldness seen in men.  Loss of attachment between the bulge stem cell population and the arrector pili muscle also explains why miniaturization is irreversible in AGA but not alopecia areata.A new model for the progression of AGA is presented.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, University of Melbourne, Victoria, Australia ; Epworth Dermatology, Victoria, Australia ; Sinclair Dermatology, Victoria, Australia.

ABSTRACT
The hair follicle is a complete mini-organ that lends itself as a model for investigation of a variety of complex biological phenomena, including stem cell biology, organ regeneration and cloning.  The arrector pili muscle inserts into the hair follicle at the level of the bulge- the epithelial stem cell niche.  The arrector pili muscle has been previously thought to be merely a bystander and not to have an active role in hair disease. Computer generated 3D reconstructions of the arrector pili muscle have helped explain why women with androgenetic alopecia (AGA) experience diffuse hair loss rather than the patterned baldness seen in men.  Loss of attachment between the bulge stem cell population and the arrector pili muscle also explains why miniaturization is irreversible in AGA but not alopecia areata. A new model for the progression of AGA is presented.

No MeSH data available.


Related in: MedlinePlus

In telogen effluvium and also alopecia areata, the arrector pili muscle (red) can be shown to be attached to the hair follicle (purple).(a) 3-dimensional reconstruction of the follicular unit with the muscles coloured red and follicles blue rotated to the left and (b) to the right.
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f7: In telogen effluvium and also alopecia areata, the arrector pili muscle (red) can be shown to be attached to the hair follicle (purple).(a) 3-dimensional reconstruction of the follicular unit with the muscles coloured red and follicles blue rotated to the left and (b) to the right.

Mentions: This apparent paradox may be explained by examination of the APM and in particular its proximal attachment to the hair follicle bulge8. The APM is a small band of smooth muscle that runs from the hair follicle to the adjacent upper dermis and epidermis. This muscle contributes to thermoregulation and sebum secretion. The APM arises proximally at the hair follicle at the bulge, which is an epithelial stem cell niche. Three-dimensional reconstructions of scalp biopsy specimens demonstrate that preservation of the APM predicts reversible hair loss (Figure 7) and that, conversely, loss of attachment between the APM and hair follicle bulge is associated with irreversible or partially reversible hair loss (Figure 8).


Androgenetic alopecia: new insights into the pathogenesis and mechanism of hair loss.

Sinclair R, Torkamani N, Jones L - F1000Res (2015)

In telogen effluvium and also alopecia areata, the arrector pili muscle (red) can be shown to be attached to the hair follicle (purple).(a) 3-dimensional reconstruction of the follicular unit with the muscles coloured red and follicles blue rotated to the left and (b) to the right.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4544386&req=5

f7: In telogen effluvium and also alopecia areata, the arrector pili muscle (red) can be shown to be attached to the hair follicle (purple).(a) 3-dimensional reconstruction of the follicular unit with the muscles coloured red and follicles blue rotated to the left and (b) to the right.
Mentions: This apparent paradox may be explained by examination of the APM and in particular its proximal attachment to the hair follicle bulge8. The APM is a small band of smooth muscle that runs from the hair follicle to the adjacent upper dermis and epidermis. This muscle contributes to thermoregulation and sebum secretion. The APM arises proximally at the hair follicle at the bulge, which is an epithelial stem cell niche. Three-dimensional reconstructions of scalp biopsy specimens demonstrate that preservation of the APM predicts reversible hair loss (Figure 7) and that, conversely, loss of attachment between the APM and hair follicle bulge is associated with irreversible or partially reversible hair loss (Figure 8).

Bottom Line: The hair follicle is a complete mini-organ that lends itself as a model for investigation of a variety of complex biological phenomena, including stem cell biology, organ regeneration and cloning.  The arrector pili muscle inserts into the hair follicle at the level of the bulge- the epithelial stem cell niche.  The arrector pili muscle has been previously thought to be merely a bystander and not to have an active role in hair disease.Computer generated 3D reconstructions of the arrector pili muscle have helped explain why women with androgenetic alopecia (AGA) experience diffuse hair loss rather than the patterned baldness seen in men.  Loss of attachment between the bulge stem cell population and the arrector pili muscle also explains why miniaturization is irreversible in AGA but not alopecia areata.A new model for the progression of AGA is presented.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, University of Melbourne, Victoria, Australia ; Epworth Dermatology, Victoria, Australia ; Sinclair Dermatology, Victoria, Australia.

ABSTRACT
The hair follicle is a complete mini-organ that lends itself as a model for investigation of a variety of complex biological phenomena, including stem cell biology, organ regeneration and cloning.  The arrector pili muscle inserts into the hair follicle at the level of the bulge- the epithelial stem cell niche.  The arrector pili muscle has been previously thought to be merely a bystander and not to have an active role in hair disease. Computer generated 3D reconstructions of the arrector pili muscle have helped explain why women with androgenetic alopecia (AGA) experience diffuse hair loss rather than the patterned baldness seen in men.  Loss of attachment between the bulge stem cell population and the arrector pili muscle also explains why miniaturization is irreversible in AGA but not alopecia areata. A new model for the progression of AGA is presented.

No MeSH data available.


Related in: MedlinePlus