Androgenetic Alopecia: New Insights Into The Pathogenesis And Mechanism Of Hair Loss

[Squeegee 2.0]

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 (Androgenetic Alopecia) 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 Androgenetic Alopecia but not alopecia areata.

A new model for the progression of Androgenetic Alopecia is presented.

https://f1000research.com/articles/4-585/v1

https://www.ncbi.nlm.nih.gov/pubmed/26339482

 

[Squeegee 2.0]

Destruction of the arrector pili muscle and fat infiltration in androgenic alopecia.

Torkamani N1, Rufaut Norwood, Jones L, Sinclair R.
Author information

Abstract
BACKGROUND:
Androgenic alopecia (Androgenetic Alopecia) is the most common hair loss condition in men and women. Hair loss is caused by follicle miniaturization, which is largely irreversible beyond a certain degree of follicular regression. In contrast, hair loss in telogen effluvium (Telogen Effluvium) is readily reversible. The arrector pili muscle (APM) connects the follicle to the surrounding skin.

OBJECTIVES:
To compare histopathological features of the APM in Androgenetic Alopecia and Telogen Effluvium.

METHODS:
Archival blocks of 4-mm scalp punch biopsies from eight patients with Androgenetic Alopecia and five with Telogen Effluvium were obtained. New 4-mm biopsies from five normal cases were used as controls. Serial 7-μm sections were stained with a modified Masson's trichrome stain. 'Reconstruct' software was used to construct and evaluate three-dimensional images of the follicle and APM.

RESULTS:
The APM degenerated and was replaced by adipose tissue in all Androgenetic Alopecia specimens. Remnants of the APM remained attached to the hair follicle. There was no fat in the normal skin specimens. Fat was seen in two of five Telogen Effluvium specimens but could be attributed to these patients also showing evidence of Androgenetic Alopecia. Quantitative analysis showed that muscle volume decreased and fat volume increased significantly (P < 0·05) in Androgenetic Alopecia compared with controls.

CONCLUSIONS:
APM degeneration and replacement with fat in Androgenetic Alopecia has not previously been described. The underlying mechanism remains to be determined. However, we speculate that this phenomenon might be related to depletion of stem or progenitor cells from the follicle mesenchyme, explaining why Androgenetic Alopecia is treatment resistant.

https://www.ncbi.nlm.nih.gov/pubmed/24579818

 

[Mohit Singh]

The disease that causes hair strands to fall out in small patches is known as Alopecia Areata. It results in sudden hair loss that may generally occur on the scalp. In some of the worst cases, it can also affect the eyebrows, eyelashes and hair on other facial regions and body parts. It takes place when the immune system of an individual attacks the hair follicles, thus causing hair loss. It occurs gradually and happens after years between instances.

 

[ALightInTheDark]

"Hair loss is caused by follicle miniaturization, which is largely irreversible beyond a certain degree of follicular regression."


I stopped here.
HRT, Estradiol, Dermaneedling says no.

 

[whatevr]

"Hair loss is caused by follicle miniaturization, which is largely irreversible beyond a certain degree of follicular regression."


I stopped here.
HRT, Estradiol, Dermaneedling says no.

I guess what they meant was,

Hair loss is caused by follicle miniaturization, which is largely irreversible beyond a certain degree of follicular regression without changing the patient's gender.