Baldness may one day be “optional”, a doctor has said.
Dr Michele Green, from Lenox Hill Hospital in New York City, claims hair follicles can be “regenerated”.
The dermatologist spoke after scientists from Mount Sinai hospital, NY, found disrupted signalling between cells in hair follicles causes them to fall out in mice.
With a similar mechanism at play in humans, the team believe blocking this process could “retain the existing hair shaft”.
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Each hair reportedly has a “life cycle”.
It starts with so-called dermal papilla cells at the base of a follicle.
These specialised cells slowly move up towards stem cells at the tip. Stem cells are basic cells that can change into a more specialised form of cell.
The stem cells receive signals from nearby dermal papilla cells “to start the next growth phase and make a new hair shaft, while the previous hair shaft is shed”, the scientists claim.
On occasion, this signalling can get disrupted, which may lead to hair loss, with no follicle to replace it.
The scientists were previously unclear how dermal papilla cells travel towards the stem cells.
Working with mice, they found “the dermal sheath surrounding growing hair follicles is a smooth muscle, whose function is to contract and push up the hair shaft, and pull up the dermal papilla”, lead author Dr Michael Rendl said.
In the “destruction” phase, the dermal sheath contracts, letting “old” strands fall out.
Experiments on human hair found a similar mechanism is at play.
This destruction happens naturally in everyone, however - if excessive - baldness may occur.
The scientists believe their discovery could one day lead to a hair loss treatment.
“Blocking the newly-discovered muscle and its contraction cannot cure baldness caused by those processes,” Dr Rendl said.
“Instead, blocking contraction and arresting the destruction phase of the cycle has the potential to retain the existing hair shaft that is otherwise lost when a new hair shaft is produced.
“This type of muscle cannot be controlled voluntarily, similar to the ones in blood vessels, but we can control it by drugs that can block contraction.
“We are excited about the possibility to develop methods for blocking sheath contraction, stopping follicle regression and preventing the loss of the existing hair before a new hair can grow.”
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The dermal sheath could potentially be tweaked to avoid the destruction phase and prevent the hair follicle going “dormant”.
“The future of hair loss looks very promising and this study shows baldness may soon be optional,” Dr Green said.
“There have been numerous research [efforts] into regenerating hair, but this study shows that the dermal sheath can preserve the hair follicle to regenerate new hair growth.”
It will take time to develop such a treatment, however.
“There is a longer way to go realistically before blocking contraction of the sheath muscle can be made a reality to halt the hair cycle in the destruction phase,” Dr Rendl said.
“It needs to be proven effective in human hair follicles in the dish first and proven safe after knowing what happens to the arrested follicles long-term.”