Hair follicle transplantation can rejuvenate scars, study finds

A new study involving three volunteers found that skin scars began to behave like intact skin after being treated with hair follicle transplants. and restored healthy patterns, even expressing genes found in unblemished healthy skin.

This finding could lead to better treatments for scarring both on the skin and in the body, offering hope for patients with extensive scarring that can impair organ function and cause disability.

After scarring, the skin never truly recovers its pre-wound function, and all efforts to date to reconstruct scars have yielded poor results. It lays the foundation for exciting new treatments that can rejuvenate even mature scars and restore healthy skin function. “

Dr. Claire Higgins, first author, Imperial’s Department of Bioengineering

The study was published today in npj Regenerative Medicine.

hope in hair

Scar tissue in the skin lacks the hair, sweat glands, blood vessels, and nerves essential to regulate body temperature and detect pain and other sensations. Scarring not only impairs movement, but can also cause discomfort and emotional distress.

Compared to scar tissue, healthy skin undergoes constant remodeling by hair follicles. Hairy skin heals faster and scars less than hairy skin, and hair transplantation has previously been shown to aid wound healing. We hypothesized that transplanting hair follicles into scar tissue could cause the scar to self-remodel.

To test their hypothesis, the Imperial researchers collaborated with Dr. Francisco Jiménez, Chief Hair Transplant Surgeon at the Meditechnia Clinic and Associate Research Professor at the University of Fernando Pessoa Canarias, Gran Canaria, Spain. They transplanted hair follicles into mature scars on the scalps of three of his participants in 2017. Researchers chose the most common type of scar called normotrophic scar, which usually forms after surgery.

They microscopically photographed 3-mm-thick scar biopsies immediately before and 2, 4, and 6 months after transplantation.

Researchers found that hair follicles drive structural and genetic changes in scars toward a healthy, undamaged skin profile.

Dr. Jimenez said: It’s a means to treat scars, and may even change your approach to preventing scars.”

skin architect

After transplantation, follicles continued to generate hair and induced recovery across skin layers.

Scarring causes the outermost layer of the skin, the epidermis, to become thinner and more prone to tearing. Six months after transplantation, the epidermis doubles in thickness and has increased cell proliferation, almost the same as intact skin. Now thick.

The next skin layer, the dermis, contains connective tissue, blood vessels, sweat glands, nerves, and hair follicles. Due to scar maturation, the dermis has fewer cells and blood vessels, but after transplantation, the number of cells doubled at 6 months, and the number of blood vessels reached almost the level of healthy skin at 4 months. . This indicates that the hair follicle influenced the growth of new cells and blood vessels within the scar.

Scars also increase the density of collagen fibers, the main structural protein in the skin, and align scar tissue so that it is stiffer than healthy tissue. It can now form a “basket weave” pattern, reducing stiffness, which is a major factor in tearing and discomfort.

The authors also found that after transplantation, scars expressed 719 genes differently than before. There was more expression of genes that promote cell and blood vessel growth, and less expression of genes that promote the scar formation process.

multi-pronged approach

The researchers do not know exactly how the transplant promoted such changes. They now uncover the underlying mechanisms so that treatments can be developed that remodel scar tissue toward healthy skin without the need for hair follicle transplantation or hair fiber growth. The results can then be tested on hairless skin or on organs such as the heart and liver that can scar after a heart attack. fatty liver disease and liver cirrhosis.

“This research has obvious applications in restoring people’s confidence, but our approach goes beyond cosmetics because scar tissue can cause problems in all organs,” Higgins said. increase.

“While current treatments for growth factor-like scarring focus on a single cause of scarring, the hair follicle likely provides multiple growth factors at once to rebuild scar tissue. Therefore, our new approach addresses multiple aspects: hair transplantation that alters scar structure and gene expression to restore function.”

This work was funded by the Medical Research Council and the Engineering and Physical Sciences Research Council (part of UKRI).