Could stem cells help reverse hair loss?

I thought that headline would grab your attention. The idea behind it grabbed my attention when I read about a new study in the journal Cell Metabolism that explored that idea and came away with a rather encouraging verdict of “perhaps”.

The research team from the University of Helsinki say that on average people lose 1.5 grams of hair every day, which over the course of a year adds up to more than 12 pounds (I think, sadly, this is the one area where I’m above average.) Normally all that falling hair is replaced by stem cells, which generate new hair follicles. However, as we get older, those stem cells don’t work as efficiently which explains why so many men go bald.

In a news release, lead author Sara Wickstrom says this was the starting point for their study.

“Although the critical role of stem cells in ageing is established, little is known about the mechanisms that regulate the long-term maintenance of these important cells. The hair follicle with its well understood functions and clearly identifiable stem cells was a perfect model system to study this important question.”

Previous studies have shown that after stem cells create new hair follicles they essentially take a nap (resume a quiescent state in more scientific parlance) until they are needed again. This latest study found that in order to do that the stem cells have to change their metabolism, reducing their energy use in response to the lower oxygen tissue around them. The team identified a protein called Rictor that appears to be the key in this process. Cells with low levels of Rictor were less able to wake up when needed and generate more hair follicles. Fewer replacements, bigger gaps in the scalp.

The team then created a mouse model to test their theory. Sure enough, mice with low or no Rictor levels were less able to regenerate hair follicles. Not surprisingly this was most apparent in older mice, who showed lower Rictor levels, decreased stem cell activity and greater hair loss.

Sara Wickstrom says this could point to new approaches to reversing the process.

“We are particularly excited about the observation that the application of a glutaminase inhibitor was able to restore stem cell function in the Rictor-deficient mice, proving the principle that modifying metabolic pathways could be a powerful way to boost the regenerative capacity of our tissues,”

It’s early days in the research so don’t expect them to be able to put the Hair Club for Men out of business any time soon. But a follicle-challenged chap can dream can’t he.

Researchers grow hairy skin from human stem cells

 Dr. Jiyoon Lee (left) and Dr. Karl Koehler (right), Indiana University School of Medicine

For years the idea of being able to regrow hair has been the domain of cheesy, middle-of-the-night TV infomercials. Now two researchers may have found a way to actually make it happen, and their work could have implications far more important than helping bald men.

Building on years of research, Dr. Jiyoon Lee and Dr. Karl Koehler from the Indiana University School of Medicine were able to use human stem cells to grow hair on skin. The complex skin model was developed by using pluripotent stem cells, a kind of stem cell that can become virtually any kind of cell in the body.

To do this, Dr. Lee, Dr. Koehler, and a team of researchers incubated the human stem cells for 150 days. During this time, the cells formed a ball shaped cluster of cells called a skin organoid. The interior of the organoid is similar to the top layer of skin, known as the epidermis, and the outside is similar to the bottom layer, known as the dermis.

In a press release, Dr. Koehler describes the skin organoid and the process in more detail.

“We’ve developed a new cooking recipe for generating human skin that produces hair follicles after about 70 days in culture. When the hair follicles grow, the roots extend outward radially. It’s a bizarre-looking structure, appearing almost like a deep-sea creature with tentacles coming out from it.”

After the skin organoid was formed, the researchers tested if it could be integrated onto the skin of nude mice by performing skin grafts. The results were remarkable as more than half of the organoids that the scientists engrafted on the mice grew human hair follicles. The skin organoid developed is similar to fetal facial skin and hair.

This skin organoid model has great potential in terms of helping with drug or gene therapies for skin disorders or recreating the earliest stages of skin cancer formation.

In the same press release, Dr. Lee discusses the potential their findings have for reconstructive purposes.

“This could be a huge innovation, providing a potentially unlimited source of soft tissue and hair follicles for reconstructive surgeries.”

The full results of this study were published in Nature.