It is widely accepted that the likelihood of
hair loss increases with age you’ve only to turn on an episode of Songs Of Praise to see how sparsely-haired the average ageing flock is.
But there is debate over whether or not this paucity of locks is down to the androgenetic alopecia, more commonly known as Male Pattern Baldness and
Female Pattern Hair Loss, or something else entirely.
Senescent Alopecia is a term that has been on the books for many years, and is used to describe hair loss in people aged 50 or over whose hair loss has more in common with an all-over, ‘diffuse’ thinning of the type most often seen in cases of
Telogen Effluvium, than the more localised thinning seen in
genetic baldness.
However lingering doubts over whether Senescent Alopecia truly exists seem to have been quashed this week with new research from Japan that claims ageing hair follicles that are denied a key collagen protein (lost as a result of ageing) simply turn into skin.
An article in the journal
Science explains how biologists at the Tokyo Medical and Dental University set about trying to understand why hair becomes thinner with ageing. Beginning with mice, they examined hair follicle stem cell growth cycles and found that “
age-related DNA damage triggers the destruction of a protein called Collagen 17A1.”
This, the article continues, then causes the transformation of stem cells into something called “epidermal keratinocytes”, which are then easily shed. The team’s next goal was to see if this was also true of humans.
Continues below diagram...
Diagram showing the mechanism of hair follicle (HF) ageing and associated hair loss, taken from the study published in Science magazine.
HFs sustain their cyclic regeneration through the intensive self-renewal of activated hair follicle stem cells aka HFSCs (blue dots). The ageing of HFSCs is triggered by DNA damage-induced COL17A1 proteolysis. Once aged HFSCs (red dots) are activated during the hair growth cycle, they leave the niche and terminally differentiate into epidermal keratinocytes and are then eliminated from the skin surface.
Research findings
During research they found that follicles in people who were over 55 were smaller, with lower levels of Collagen 17A1. Summing up the findings in Science, writer Laurel Hamers quotes the study’s lead scientist Emi Nishimura: “
We assume that… ageing processes and mechanisms [similar to those in the mice]
explain the human age-associated hair thinning and hair loss.”
The Japanese medical team now believe there is scope for further investigation into how their discoveries can be used to fight this type of
thinning hair.
The findings appear to be at loggerheads with a
2011 study which examined the hair counts of 2,149 patients and concluded that old age was not a significant cause of hair loss.
Regardless, any new research into the complex mechanisms of hair growth are always welcome as previous studies helped lead the way to the development of only two MHRA licensed and FDA approved
genetic hair loss treatments available today.
Whilst with genetic hair loss in men and women it is true that the earlier you treat it the more likely you are to see significant regrowth results, some people may not start to experience thinning until later in life. In these instances, a
hair loss specialist can help you explore all the options available to you.