The Arrector Pili Muscle (aka Goosebump Muscle) | Hair Loss Cure 2020

I initially wrote this put up on the arrector pili muscle in 2016, with updates in 2017 and 2020.

Recently, I discovered a 2021 video through which the semi-retired Dr. Andrew Messenger of the UK makes some vital claims. He thinks that present hair loss remedies primarily impression the hair cycle. They don’t reverse miniaturization. Moreover, he theorizes that the structural modifications in miniaturized hair follicles are maybe extra profound that beforehand foreseen. In explicit, the  irreversible destruction of the arrector pili muscle and subsequent fats infiltration. He presents a picture from Dr. Rodney Sinclair’s 2014 paper on this topic, which I mentioned in one in all my previous updates additional beneath.

However, I’m skeptical about these conclusions. It looks as if Dr. Ralf Paus within the second half of the above video can also be optimistic in regards to the potential reversal of miniaturized hairs by way of numerous potential remedies. I’m particularly curious as to how hair transplants on folks with intensive Norwood 5-6 degree balding work so properly (if arrector pili muscle tissues all through their scalp are destroyed). Also of curiosity, there are fairly a number of spectacular male-to-female transition hair development outcomes which can be solely credited to drugs comparable to Dutasteride, Spironolactone and Estrogen.

Please see the underside of this put up “My Points of Contention” part the place I elaborate additional on these arguments. I’ve e-mailed each medical doctors to see if they’ve any additional suggestions.

Update: August 7, 2020 

Goosebumps, the Sympathetic Nervous System and Hair Growth

Yesterday, Taiwanese and US researchers revealed an vital paper titled: “Cell Types Promoting Goosebumps Form a Niche to Regulate Hair Follicle Stem Cells.” The work was led by Dr. Lin Sung-jan of National Taiwan University, in collaboration with researchers from Harvard University (US).

The scientists made some vital discoveries in relation to the arrector pili muscle (APM), and the sympathetic nervous system. The APM maintains sympathetic innervation to hair follicle stem cells. (HFSCs) The sympathetic nerve prompts HFSCs by way of synapse-like contacts and norepinephrine. An vital quote:

“APMs are often lost in the scalp skin of people with androgenetic alopecia. It is possible that in such skin, loss of APMs leads to the loss of sympathetic nerves, making HFSCs more difficult to activate. Our results also suggest the potential of using selective β2 agonists to promote HFSC activation.”

Lin’s workforce discovered that the organic mechanism behind baldness in males is closely connected to the sympathetic nervous system. Hair follicle stem cells activate after receiving alerts by way of what are often known as ADRB2 receptors. Based on these findings, the researchers hope to develop small molecule medication that may activate ADRB2 receptors as a method of regenerating hair.

Goose bumps are a sympathetic nerve response involving the contraction of tiny muscle tissues throughout our our bodies. These arrector pili muscle tissues causes hair to face up straight on the pores and skin once we are fearful and underneath menace. The scientists intention to in the end management the muscle-nerve system that drives hair regeneration. A video of those findings is embedded beneath. It is sort of one thing to see Dr. Lin Sung-jan being mobbed by the media.

Jan 10, 2017

Androgenetic Alopecia: New insights into the function of the Arrector Pili Muscle

Several weeks in the past, the arrector pili muscle received vital protection in a number of newspapers world wide. Famed Australian dermatologist Dr. Rodney Sinclair co-authored an vital paper titled “The arrector pili muscle, the bridge between the follicular stem cell niche and the interfollicular epidermis” that was simply revealed this month.

Dr. Sinclair has been concerned on this space of hair loss analysis for a number of years. See his 2014 paper titled: Beyond goosebumps: Does the arrector pili muscle have a job in hair loss? Also see related material on his website. Australian newspapers have been particularly on this newest examine and its findings as evidenced by articles comparable to this one and this one.

The Arrector Pili Muscle

Arrector pili muscle tissues are small muscle tissues connected to particular person human hair follicles on each the scalp in addition to physique (so we have now hundreds of thousands of those muscle tissues all through our our bodies). Contraction of those muscle tissues causes hairs to face up, a phenomenon that is named goosebumps. Therefore, the musculus arrector pili is sometimes called the goosebump muscle.

Every hair root is linked to the arrector pili. This clean muscle contracts in response to alerts from the “fight or flight” sympathetic nervous system.

Arrector Pili Muscle Degeneration and Hair Loss

In current years, a number of research have come out that counsel a attainable connection between the arrector pili muscle degenerating (the place it will get changed by fats) and hair loss because of the subsequent disconnection between varied hair follicle stem cell populations. It is feasible that an intact arrector pili muscle performs an important function within the upkeep of follicular integrity and stability.

However, there are various uncertainties about this idea that I talk about within the subsequent part. It appears that whereas in alopecia areata (AA) sufferers the arrector pili muscle stays intact, this isn’t true in androgenetic alopecia (AGA) sufferers. Unfortunately, over 95 p.c of balding males endure from AGA. So this might be why it’s a lot simpler to develop again hair for folks with AA in comparison with folks with AGA.

However, the speed at which the arrector pili muscle degenerates and will get changed by fats varies considerably between sufferers and between particular person hairs on the identical scalp. Some miniaturized vellus hairs in balding areas may even by no means lose most of their arrector pili muscle connection.

My Points of Contention

• According to Dr. Sinclair’s personal quote from a previous paper, “It remains unclear whether arrector pili muscle regression is a cause or effect of permanent follicle miniaturization“. I think this is the crux of the issue surrounding this theory/hypothesis.
• I am curious why hair that is transplanted from the back of a person’s scalp to the front grows so well if the arrector pili muscles in front have been destroyed? Surely the transplanted hair cannot just automatically regenerate the arrector pili muscle?
• Related to the above, an important Japanese study from 2012 concludes that correctly transplanted hair can re-enable “connectivity and cooperation” with the arrector pili muscle and nerve system. In impact, it is perhaps very attainable to reactivate or regenerate the APM.
• In Dr. Tsuji and his team’s groundbreaking technology “the transplanted primordium also forms connections with surrounding tissues (arrector pili muscle and nerves) and repeats normal hair cycles”.
• There are 100s of on-line anecdotal studies with earlier than and after pictures of individuals regrowing long-lost hair in bald scalps. Miracle outcomes are particularly frequent in folks present process male-to-female transition regimens. You can even discover many studies of unusual hair regrowth in many elderly males who just lately began taking dutasteride for enlarged prostate points. Maybe they regenerated their arrector pili muscle tissues; or possibly these muscle tissues at all times remained intact despite extreme AGA; or possibly one can regenerate hair with out the necessity for having any intact arrector pili muscle tissues?
• It is unclear when precisely we have now a degree of no return the place the arrector pili muscle is basically or solely changed by fats and hair stops rising (both as a trigger or impact). It looks as if there may be vital variation relying on particular person and hair follicle. In many instances, the arrector pili may not be solely degenerated and changed by adipose tissue even in areas of the scalp the place one has been bald for a number of a long time. In such instances, subsequent hair and muscle regeneration might then be attainable by way of one thing like Dutasteride or Finasteride.