Japanese scientists use stem cells to grow hair on bald mice, raising hopes of a cure for baldness
Regardless of age, race or nationality, millions of men across the world are bothered by baldness.
The sad news is that traditional hair restoration surgery — which works by transplanting hair follicles from the back of the head to the front — wouldn’t work if you have few hair follicles left, or none at all.
So if you’re a man who’s lost all your hair and would give anything to get them back, here’s good news for you.
Japanese researchers have successfully grown hair on hairless mice by implanting hair follicles created from adult stem cells — sparking new hopes for a more lasting and effective cure for baldness.
Unlike current hair transplant methods that move existing hair follicles from one area of the scalp to another, the new approach actually spurs the creation of new hair follicles from existing cells, and the consequent grow of new hair.
The team, made up of researchers from many Japanese universities and led by Dr. Takashi Tsuji, a professor at the Research Institute for Science and Technology at the Tokyo University of Science (TUS), bioengineered hair follicles and transplanted them into the skin of lab mice that had been genetically engineered to be hairless. The mice grew hair, which continued regenerating in normal growth cycles after old hairs fell out. Their findings are published in the April 18 online issue of the science magazine Nature Communications.
“It’s exciting because it shows (that) a cell-based approach for treating hair loss is maybe feasible,” George Cotsarelis, a dermatologist at the University of Pennsylvania in Philadelphia tells the magazine Science News.
The study is also significant for scientists working to regenerate organs such as salivary glands because, early in their development, these glands form in a process similar to hair, says Dr. Tsuji.
And while most of us take hair for granted, growing hair follicles is actually a complex process. These follicles develop when two different types of cells — epithelial and mesenchymal cells — interact with each other. Epithelial cells grow very quickly and shed; mesenchymal cells direct epithelial cells to make a follicle.
In their previous work, Dr. Tsuji and his colleagues used epithelial and mesenchymal cells from mouse embryos to bioengineer follicles and hair shafts in the lab. But until now, it was unclear whether these organized clusters of cells would spur the growth of normal hair when inserted into mouse skin.
In their new work, the Japanese scientists transplanted a group of the engineered hair follicles into the skin of the backs of hairless mice. After about two weeks, hairs began to grow.
How exactly did they do this?
To produce the cells, the scientists undertook the following steps:
• Harvested epithelial stem cells and mesenchymal cells from adult mouse hair follicles.
• Growing the two cell types together, the team engineered “seed” hair follicles.
• When transplanted, these seed follicles made whisker-type hair.
• Turning to human cells, they collecting cells from the scalps of men with male pattern baldness.
• They then created a “seed” hair follicle by combining adult epithelial stem cells and dermal papilla cells from a normal mouse. Both cells types are basic cells that are found in the skin; dermal papilla are nipple-like projections at the base of hairs.
• The scientists then transplanted the cells into the back of mice genetically engineered to be bald.
• 28 bioengineered follicle germs were transplanted to a 1 centimeter- (0.39 inch-) circular patch of skin. This was meant to recreate what’s considered a normal hair density — about 120 hair shafts per square centimeter (0.15 square inch) or 60-100 hair shafts per square centimeter.
• Within three weeks, the hair follicles implanted with the cells had grown hair in about 70 percent of the tested mice.
• The implanted follicle germs developed all the proper structures and the resulting hairs connected properly with the skin, muscle and nerves of the hairless mice.
• The stem and progenitor cells, along with their niches, were recreated in the bioengineered follicles. This made them go through the normal cycle of growing hair, shedding and making new hair.
• The bioengineered follicles even got goose bumps when researchers injected the region around them with acetylcholine, a drug that causes muscles to contract.
• The new hair was as solid as that in the donor mice and carried the exact patterns as the original, including curves.
• The resulting hair density was 124 hair shafts per square centimeter (plus or minus 17 shafts), which the scientists considered satisfactory.
The researchers also found that when they changed the number of the transplanted stem cells, this changed the density and the number of hairs that grew on the lab mice.
By attaching a nylon thread to the engineered follicles, the scientist were able to guide the hair to grow outward and ensure that these didn’t become ingrown or point in the wrong direction.
“You have to make hair that is positioned right,” Cheng-Ming Chuong, a stem cell and regeneration researcher at the University of Southern California in Los Angeles tells Science News. Similar experiments involving transplanted follicles done previously had produced hair that grew in random directions — or had even formed cysts, she says. But the new study succeeded in getting the follicles to grow in an organized way.
The findings will allow people to use their own cells for implants that will give them back their hair. Combining this new technique with existing technologies is thus expected to improve treatment for baldness.
Interestingly, the Japanese scientists also found that by adding a particular type of stem cell to the bioengineered follicle, the lab mice were able to grow colored — rather than white hair. This means that in the future, men could potentially restore both their hair and their hair color from youth.
Still, critics point out that these findings don’t show whether the number of human hair follicles can be amplified, so that more hair is produced.
“There is a need for a number of improvements, including magnification techniques for stem cells, before the method is applied to a large surface as in humans,” Dr. Tsuji says. “We are looking at some 10 years from now.”
Also, the technique has yet to be tested in humans. And while this may possibly be done soon, the technique is still at the stage where it would be exorbitant.
“Our current study thus demonstrates the potential for not only hair regeneration therapy but also the realization of bioengineered organ replacement using adult somatic stem cells,” Dr. Tsuji says in a press release.
Dr. Tsuji also tells the Associated Press in a video interview, “At this point, this kind of precise cellular operation is only possible by our team.” His lab at TUS specializes in cutting-edge regenerative medicine, and was responsible for the 2011 experiments that used stem cells to regrow a tooth in a mouse’s mouth.