January 05, 2011
Baldness Due To Progenitor Cell Deficiency

Not enough stem cells convert into progenitor cells in hair follicles and baldness results.

PHILADELPHIA Ė Given the amount of angst over male pattern balding, surprisingly little is known about its cause at the cellular level. In a new study, published in the Journal of Clinical Investigation, a team led by George Cotsarelis, MD, chair of the Department of Dermatology at the University of Pennsylvania School of Medicine, has found that stem cells play an unexpected role in explaining what happens in bald scalp.

The stem cells available for conversion into progenitor cells appear numerous enough. They just need a signal to tell them to do their duty and suddenly receding hairlines would reverse course and bald spots would spout long strands.

Using cell samples from men undergoing hair transplants, the team compared follicles from bald scalp and non-bald scalp, and found that bald areas had the same number of stem cells as normal scalp in the same person. However, they did find that another, more mature cell type called a progenitor cell was markedly depleted in the follicles of bald scalp.

The researchers surmised that balding may arise from a problem with stem-cell activation rather than the numbers of stem cells in follicles. In male pattern balding, hair follicles actually shrink; they donít disappear. The hairs are essentially microscopic on the bald part of the scalp compared to other spots

Do the stem cells collect too many genetic mutations or other damage? Or do other cells around them fail to send chemical messages to tell them to differentiate into progenitor cells?

I expect skin and hair rejuvenation therapies to come faster than rejuvenation therapies for the rest of the body. The skin is so accessible. Plus, people want youthful appearances and will pay dearly for them. One could make a fortune with a treatment that restores hair follicle progenitor cell count. The financial incentives are there.

Share |      Randall Parker, 2011 January 05 10:46 PM  Aging Mechanisms

Brett Bellmore said at January 6, 2011 3:58 AM:

For what it's worth, I came out of chemotherapy with more hair than I went into it with. And this is not an uncommon occurrence. This rather suggests to me that the stem cells are being suppressed somehow by their neighbors. Your hair falls out during chemo because the faster dividing cells in the follicles are killed off, and then eventually repopulated by resistant cell lines. (This latter happens, surprisingly, before the chemo is even over.)

Perhaps those of us who end up with more hair as a result of chemo, have had the cell lines that are suppressing the stem cells preferentially killed off?

Lou Pagnucco said at January 6, 2011 1:09 PM:

First, since these changes occur in a coordinated way over a large area of tissue, it seems to me more proper refer to this hair loss as "programmed development" rather than "damage."

The paper -
"Transplants from balding and hairy androgenetic alopecia scalp regrow hair comparably well on immunodeficient mice"

- seems to show that some systemic factor is also involved, since the miniaturized follicles excised from balding scalp revive and re-grow when transplanted to immunodeficient mice.

Lobo Solo said at January 6, 2011 7:22 PM:

FWIW, I remember reading some time ago that after a hair transplant that the area around a transplanted follicle begins regrow hair. Somehow the healthy thick hair encouraged the regrowth in the dormant cells.

Lono said at January 7, 2011 9:13 AM:

I hope they finally nail a treatment for this!

Although I would personally benefit - I also think we all would benefit as many researchers could then re-focus on less immediately lucrative but certainly more important rejuvenation research on other parts of the body.

Make it so boffins!

kurt9 said at January 7, 2011 10:48 AM:

For now, take Dutasteride (or one of its generics) along with topical application of Minoxidil. This combination does indeed work.

Lou Pagnucco said at January 8, 2011 12:04 PM:


Re: "more important rejuvenation research on other parts of the body"

It may be that suppression of stem cell function may share some common mechanisms - so, while scalp hair may not be critical to survival, it is highly accessible for study, and, maybe finding why it atrophies may explain why other more vital organs also wither with age. Male balding is correlated and anti-correlated with several diseases of aging.

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