A joint team of Korean and U.S. researchers has discovered the possibility of developing a treatment for gray hair using pigment stem cells in hair follicles.

A joint research team, led by Professors Lee Joo-hee (left) and Lee Young-in at Severance Hospital and David E. Fisher at Harvard Medical School, has discovered the possibility of developing a treatment for gray hair.
A joint research team, led by Professors Lee Joo-hee (left) and Lee Young-in at Severance Hospital and David E. Fisher at Harvard Medical School, has discovered the possibility of developing a treatment for gray hair.

According to the Severance Hospital, melanocytes in the hair follicle determine a person's hair color. The higher the amount of stem cells that synthesize melanin pigment, the darker the hair color is. However, as people get older, the number of melanocytes decreases, and the functions decline, leading to white hair growth.

The symptom mainly occurs in people in their 30s to 40s. However, those in their 10s to 20s get such symptoms sometimes due to genetics, living environment, and stress.

To provide a treatment option, the team, led by Professors Lee Joo-hee and Lee Young-in at the Severance Hospital and David E. Fisher at Harvard Medical School, researched constructing a white hair model using human hair follicle tissue.

Based on the mechanism that early differentiation of melanin pigment stem cells depletes melanin pigment stem cells and causes ectopic pigmentation, and ectopic pigmentation promotes the differentiation of melanin pigment stem cells to induce white hair, the team used an ex vivo model to evaluate the pigmentation of melanocytes and the expression of differentiation genes in human hair follicles.

Researchers measured ectopic pigmentation of hair follicle protrusions by exposing specific stress signal mediators, including ionizing radiation, hydrogen peroxide, and noradrenaline, to several hair follicles isolated from the human scalp tissue.

In an experiment that exposed human hair follicles in vitro to ionizing radiation and hydrogen peroxide to observe the differentiation of abnormal melanocytes, the team found that ectopic pigmentation significantly increased in the protruding portion of the exposed hair follicle.

They also exposed the human hair follicles to noradrenaline, a neurotransmitter released by sympathetic neurons during acute stress. Similar to the previous result, the team confirmed that ectopic pigmentation significantly increased in the hair follicle area.

"This study is significant in that we managed to construct the world's first human hair follicle tissue model using an ex vivo experiment," Professor Lee Joo-hee said.

Identification of markers for successfully separating and culturing human scalp hair follicles and quantitatively analyzing the initial process of abnormal differentiation of pigment stem cells due to external oxidative stress and the aging process is an important step in developing a novel treatment for various pigment disorders as well as proving the mechanism of white hair growth, she added.

Experimental Dermatology published the result of the study in its latest issue.

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