S Foote.
Experienced Member
- Reaction score
- 66
Below is a copy of a letter i drafted to explain the background to my theory, and suggest experiments in one aspect of it. I thought it would be useful to post this here to give people some insight into the idea, and why i argue this mechanism in human hair growth.
"This proposal involves an engineer’s overview of mammalian biology, and the brief description below is intended to outline the proposal to scientists interested in "systems" biology. In my opinion, the argument leads to an important testable question about gender immunology and autoimmunity. It is for this reason that i am seeking the input of system biology experts on this argument.
It proposes a role for the bodies fluid systems, apart from the supply of nutrients and waste removal within tissues. The argument offers evidence for an evolved role of "hydraulic" signalling through local changes in fluid levels and pressures, to effect cellular changes in tissues.
The idea started with a hydraulic consideration of the mammalian dermal system, in the light of what is known about the local biology. The dermal tissue experiences a significant "hydraulic" change in response to environmental temperature changes.
http://www.biotopics.co.uk/humans/skinte.html
In cold conditions, blood flow moves away from the bodies surface to help prevent heat loss, the reverse happens in hot conditions. This reduces the local tissue fluid pressures in cold conditions, and increases them in hot conditions.
There are advantages to be had from these local changes in fluid levels and pressures. In hot conditions, this ensures a good supply of fluid to the sweat glands. Sweat glands have no "pumping" mechanism, and so must rely upon the local fluid pressures for their rate of secretion.
The central argument in my proposal that generates the more serious question’s, is that hair production has also evolved to be "adjustable" by these hydraulic changes. An increase in hair growth in cold environments is desirable, and noted in hairy mammals (winter coat). A simple link with the primary hydraulic dermal changes to cold, is the easiest way for this to be achieved in evolution.
The amount of hair produced depends upon the period of anagen enlargement of the hair follicle, and the size of anagen follicle achieved.
http://www.regaine.co.uk/men/sci_thehairgrowthcycle.asp
The expanding anagen hair follicle forms a hollow pocket in the dermal tissue. As the follicle expands, it has to move dermal tissue cells aside. This must involve some degree of resistance to follicle expansion from the dermal tissue. As the follicle is "hollow", there is also scope for a pressure differential to exist. Even a small increase in dermal tissue fluid pressures caused by increased local hydraulic forces, will increase the force behind dermal cells resisting the anagen enlargement of hair follicles. The tendency for the dermal tissue to "close a hollow space" is increased.
All normal cell growth (including hair follicle cells), is subject to the overriding constraint of normal contact inhibition.
http://www.steadyhealth.com/encyclopedi ... inhibition
Given this accepted cell growth control, increased hydraulic pressure in the dermis will initiate contact inhibition of follicle expansion earlier in the anagen phase, resulting in smaller follicles and less hair growth.
This is just what is needed in early evolving hairy mammals.
According to this, increased local tissue fluid pressures mean less hair growth, and reduced tissue fluid pressures mean more hair growth.
It is when this idea is transposed upon modern humans that some important questions arise?
The most recognised "changer" of human hair growth patterns, are male hormones, in particular the testosterone derivative dihydrotestosterone (DHT).
The current arguments and research into androgen related hair growth/loss, is not what i wish to dwell upon here. At this time, i will only quote part of a recognised leading researcher’s response to my proposal, as it relates to human hair growth.
Dr Marty Sawaya's background is described here:
http://www.hairloss-research.org/sawaya.html
Her response to my proposal:
"It is a very complex process, but your thoughts are very organized and on the right path, similar to what others have been proposing, and in some ways yours are more straightforward. I think you've done a good job in thinking this through......
Hope this helps...
regards
Marty Sawaya"
In my opinion, the most important question arises when the recognised effect of DHT upon human body hair growth, is considered in terms of this hydraulic mechanism?
The areas of DHT induced body hair growth are also areas where there are increased concentrations of superficial lymphatic vessels.(pubis, armpits, beard). According to this proposal, DHT must be increasing lymphatic drainage, reducing local tissue fluid pressures, and allowing larger anagen follicle expansion.
Such an action of a male hormone makes sense in terms of the "performance enhancing" effects of androgens. This would increase tissue fluid turnover, increasing nutrient supply and waste removal in tissues. Lymphatic contractions are due to muscle fibres in the vessel walls, and it is possible for androgens to effect contractions given current knowledge.
http://www.annalssurgicaloncology.org/c ... suppl/275S
I can currently find no reference to any accepted gender difference in lymphatic efficiency, but such a situation would make sense of some serious gender related diseases. Lymphatic drainage rates would have a profound effect upon immune cell traffic, and the expression of genes relating to inflammation.
http://www.ncbi.nlm.nih.gov/pubmed/1683 ... t=Abstract
A reduced lymphatic efficiency in women would help to explain the increased incident of autoimmune diseases. It is accepted that sex hormones play a role here, so is DHT a major player?
http://www.aarda.org/women.html
It is possible to conduct in-vitro studies into lymphatic contractions, but i can find no reference to such studies involving sex hormones? I feel that such studies could both shed light upon wider "systematic" effects of androgens, and answer questions in gender related disease.
My intention in this short outline is to encourage interest in testing this question from those in a position to do this. I can provide many references to further support this argument, and would be happy to respond to specific questions.
Stephen Foote."
"This proposal involves an engineer’s overview of mammalian biology, and the brief description below is intended to outline the proposal to scientists interested in "systems" biology. In my opinion, the argument leads to an important testable question about gender immunology and autoimmunity. It is for this reason that i am seeking the input of system biology experts on this argument.
It proposes a role for the bodies fluid systems, apart from the supply of nutrients and waste removal within tissues. The argument offers evidence for an evolved role of "hydraulic" signalling through local changes in fluid levels and pressures, to effect cellular changes in tissues.
The idea started with a hydraulic consideration of the mammalian dermal system, in the light of what is known about the local biology. The dermal tissue experiences a significant "hydraulic" change in response to environmental temperature changes.
http://www.biotopics.co.uk/humans/skinte.html
In cold conditions, blood flow moves away from the bodies surface to help prevent heat loss, the reverse happens in hot conditions. This reduces the local tissue fluid pressures in cold conditions, and increases them in hot conditions.
There are advantages to be had from these local changes in fluid levels and pressures. In hot conditions, this ensures a good supply of fluid to the sweat glands. Sweat glands have no "pumping" mechanism, and so must rely upon the local fluid pressures for their rate of secretion.
The central argument in my proposal that generates the more serious question’s, is that hair production has also evolved to be "adjustable" by these hydraulic changes. An increase in hair growth in cold environments is desirable, and noted in hairy mammals (winter coat). A simple link with the primary hydraulic dermal changes to cold, is the easiest way for this to be achieved in evolution.
The amount of hair produced depends upon the period of anagen enlargement of the hair follicle, and the size of anagen follicle achieved.
http://www.regaine.co.uk/men/sci_thehairgrowthcycle.asp
The expanding anagen hair follicle forms a hollow pocket in the dermal tissue. As the follicle expands, it has to move dermal tissue cells aside. This must involve some degree of resistance to follicle expansion from the dermal tissue. As the follicle is "hollow", there is also scope for a pressure differential to exist. Even a small increase in dermal tissue fluid pressures caused by increased local hydraulic forces, will increase the force behind dermal cells resisting the anagen enlargement of hair follicles. The tendency for the dermal tissue to "close a hollow space" is increased.
All normal cell growth (including hair follicle cells), is subject to the overriding constraint of normal contact inhibition.
http://www.steadyhealth.com/encyclopedi ... inhibition
Given this accepted cell growth control, increased hydraulic pressure in the dermis will initiate contact inhibition of follicle expansion earlier in the anagen phase, resulting in smaller follicles and less hair growth.
This is just what is needed in early evolving hairy mammals.
According to this, increased local tissue fluid pressures mean less hair growth, and reduced tissue fluid pressures mean more hair growth.
It is when this idea is transposed upon modern humans that some important questions arise?
The most recognised "changer" of human hair growth patterns, are male hormones, in particular the testosterone derivative dihydrotestosterone (DHT).
The current arguments and research into androgen related hair growth/loss, is not what i wish to dwell upon here. At this time, i will only quote part of a recognised leading researcher’s response to my proposal, as it relates to human hair growth.
Dr Marty Sawaya's background is described here:
http://www.hairloss-research.org/sawaya.html
Her response to my proposal:
"It is a very complex process, but your thoughts are very organized and on the right path, similar to what others have been proposing, and in some ways yours are more straightforward. I think you've done a good job in thinking this through......
Hope this helps...
regards
Marty Sawaya"
In my opinion, the most important question arises when the recognised effect of DHT upon human body hair growth, is considered in terms of this hydraulic mechanism?
The areas of DHT induced body hair growth are also areas where there are increased concentrations of superficial lymphatic vessels.(pubis, armpits, beard). According to this proposal, DHT must be increasing lymphatic drainage, reducing local tissue fluid pressures, and allowing larger anagen follicle expansion.
Such an action of a male hormone makes sense in terms of the "performance enhancing" effects of androgens. This would increase tissue fluid turnover, increasing nutrient supply and waste removal in tissues. Lymphatic contractions are due to muscle fibres in the vessel walls, and it is possible for androgens to effect contractions given current knowledge.
http://www.annalssurgicaloncology.org/c ... suppl/275S
I can currently find no reference to any accepted gender difference in lymphatic efficiency, but such a situation would make sense of some serious gender related diseases. Lymphatic drainage rates would have a profound effect upon immune cell traffic, and the expression of genes relating to inflammation.
http://www.ncbi.nlm.nih.gov/pubmed/1683 ... t=Abstract
A reduced lymphatic efficiency in women would help to explain the increased incident of autoimmune diseases. It is accepted that sex hormones play a role here, so is DHT a major player?
http://www.aarda.org/women.html
It is possible to conduct in-vitro studies into lymphatic contractions, but i can find no reference to such studies involving sex hormones? I feel that such studies could both shed light upon wider "systematic" effects of androgens, and answer questions in gender related disease.
My intention in this short outline is to encourage interest in testing this question from those in a position to do this. I can provide many references to further support this argument, and would be happy to respond to specific questions.
Stephen Foote."