Bald? Help’s on the Horizon

Scientists now have a better understanding of how hair grows, making treatment of baldness a possibility.

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It’s yet to become a hit in online chatrooms or a hot topic on medical blogs. But when it will, researchers like George Cotsarelis and Elaine Fuchs will surely attain cult status. After all, they are working on a vexatious problem that has troubled — and continues to trouble — countless number of men and women all their lives.

Both Cotsarelis, a dermatologist at the Pennsylvania University School of Medicine, and Fuchs, an experimental biologist at Rockefeller University, are trying to get to the bottom of the problem of hair loss, a condition — though not life threatening — that leaves many distressed and aghast.

The thinning of locks, which half the world population experiences by the age of 50, is not treated lightly by those who suffer from it, but there is no convincing cure for it yet. It’s another matter that quacks and cosmetic firms exploit this hapless situation to make a killing. Costly procedures like hair transplant may be better than the mere application of gels and oils, but they are yet to become a viable option.

Cotsarelis and Fuchs are trying to address this problem with the help of advanced cellular and molecular techniques. A therapy may still be far from reaching the clinic, but the scientists concede that now they at least have a better understanding of how hair grows.

“Over the last 10 years, there has been much progress in understanding hair follicular development. We believe this will translate into clinical benefits, but it is impossible to know when,” Cotsarelis told KnowHow.

He should know. After all, his team showed for the first time — in a paper in the journal Nature last May — that hair follicles can be regenerated. This put to rest a half-a-century-old belief that mammalian hair follicles form only during development.

Much to their surprise, Cotsarelis and his colleagues found that new hair follicles are formed in a mouse when it is wounded deeply enough (nearly five millimetres deep). More importantly, the new follicles were slightly different from the ones that develop during the embryo stage. While in embryos, follicles are produced by skin stem cells, the latter had very little to do in the follicular development in the wounded mouse. Instead, the epidermal cells — that give rise to the outermost layer of the skin — were reprogrammed to make hair follicles. The instruction for this, they found, came from a class of proteins called “wnts”. These wnts proteins are known to play a role in hair follicle development in an embryo.

Close observation revealed that when the wound is deep, stem cells are rushed to the area of injury. Unexpectedly, the regenerated hair follicles originated from non-hair-follicle stem cells.

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“We’ve found that we can influence wound healing with wnts and other proteins that allow the skin to heal in a way that includes all the normal structures of the skin, such as hair follicles and oil glands,” Cotsarelis said.

By introducing more wnt proteins to the wound, the researchers could take advantage of the embryonic genes that promote follicular growth.

Conversely, by blocking the proteins, they could stop the production of hair follicles in the healed skin. Moreover, an increase in the availability of the wnt proteins also meant an increase in the number of new hair follicles.

The novel technique for which the Pennsylvania team received a patent is now being pursued by a new biotech firm called Focilla Inc, which Cotsarelis co-founded with the Boston-based PureTech Ventures. “If everything goes well, we could have a product in the market in four years,” David Steinberg of PureTech told KnowHow. The firm is confident that it will be a big player in the baldness treatment market, which in the US alone is said to be in the range of $ 2-4 billion.

When a human baby is born, some five million hair follicles cover its body. An average human head has 100,000 follicles spread across the scalp. For many, these follicles cease production with age. It is said that a healthy individual sheds around 100 strands a day. This is not a cause for worry as long as the hair is constantly replaced and the losses occur evenly around the whole scalp. Each follicle in a developing embryo receives a reservoir of stem cells that are capable of differentiating to produce hair. Each follicle can grow up to 20 individual strands of hair — of course one after another — during a person’s lifetime.

Scientists have always been stumped by the phenomenon of baldness because it is not ubiquitous in the animal kingdom. Only humans and the stumptailed macaque are known to suffer from androgenetic alopecia, as baldness is scientifically known. “We don’t know why,” says Cotsarelis.

Like Cotsarelis, Fuchs of the Howard Hughes Medical Institute in Rockefeller University was fascinated by skin stem cells, which unlike most other adult stem cells, can be easily grown in the laboratory. What intrigued her most was the skin stem cells’ ability to grow into two very distinct structures — skin and hair. Her inquiry as to how a skin stem cell decides to become skin or hair over the years has finally yielded some chemical clues.

In a paper in the February 2008 issue of Genes & Development, Fuchs, her postdoc student Michael Rendl, and others zeroed in on a protein called BMP which they found “ratchets up and clamps down” the activity of key genes in dermal papilla, a type of skin cell whose unique collection of proteins ultimately instructs skin stem cells to make hair follicles.

“Scientists don’t know how dermal papilla cells are programmed to provide the instructive signals to stem cells, but now we know that BMP signals play a crucial role,” Rendl observed in a release.

The work by Fuchs’ team has taken science a step closer to unlocking the secret of beautiful hair. And also perhaps an inch closer to finding a way to stem the abnormal thinning of locks.

Sources: The Telegraph (Kolkata, India)

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