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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

Horizontal section of skin biopsy from a hairy forearm showing follicles to exist singly or in groups of three, known as Mejeres trios.
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f5: Horizontal section of skin biopsy from a hairy forearm showing follicles to exist singly or in groups of three, known as Mejeres trios.

Mentions: Scalp hairs arise from FUs that are best seen on horizontal scalp biopsy. FUs comprise a primary follicle that gives rise to an arrector pili muscle (APM), a sebaceous gland, and multiple secondary follicles that arise distal to the APM (Figure 3). Hairs from secondary follicles commonly emerge from a single infundibulum (Figure 4). In contrast, hairs over the beard, trunk, and limbs do not give rise to secondary hairs and exist singly or in groups of three, known as Mejeres trios (Figure 5). Miniaturization occurs initially in the secondary follicles, leading to the reduction in hair density that precedes visible baldness (Figure 6). Baldness ensues when all of the hairs within an FU are miniaturized.


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

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

Horizontal section of skin biopsy from a hairy forearm showing follicles to exist singly or in groups of three, known as Mejeres trios.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f5: Horizontal section of skin biopsy from a hairy forearm showing follicles to exist singly or in groups of three, known as Mejeres trios.
Mentions: Scalp hairs arise from FUs that are best seen on horizontal scalp biopsy. FUs comprise a primary follicle that gives rise to an arrector pili muscle (APM), a sebaceous gland, and multiple secondary follicles that arise distal to the APM (Figure 3). Hairs from secondary follicles commonly emerge from a single infundibulum (Figure 4). In contrast, hairs over the beard, trunk, and limbs do not give rise to secondary hairs and exist singly or in groups of three, known as Mejeres trios (Figure 5). Miniaturization occurs initially in the secondary follicles, leading to the reduction in hair density that precedes visible baldness (Figure 6). Baldness ensues when all of the hairs within an FU are miniaturized.

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