Stimulating Stem Cells to Encourage Hair Growth

UCLA researchers have revealed a new way to activate stem cells within hair follicles that stimulate hair growth. The hope is this discovery will lead the way to the development of drugs that allow bald individuals and those with alopecia to once again grow hair. The research was led by scientists William Lowry and Heather Christofk of UCLA's Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research. The details of their findings were recently published in Nature Cell Biology.

About Hair Follicle Stem Cells

Hair follicle stem cells are best described simply as older cells within hair follicles that are present in human skin. They generate hair across an individual's lifetime. These cells are quiescent, meaning they are typically dormant yet they can activate quite rapidly in a new hair cycle when the growth of new hair occurs. The hair follicle stem cells' quiescence is regulated by an array of factors. In some instances, they do not activate and hair loss occurs.

Study Details

The researchers determined the metabolism of hair follicle stem cells is unique from other skin cells. Cellular metabolism occurs when nutrients necessary for cell division break down, create energy and react to their environment. The metabolism process makes use of enzymes that change nutrients to generate metabolites. Hair follicle stem cells gradually consume a form of sugar, known as glucose, from the body's bloodstream. The glucose is processed to gradually create a metabolite known as pyruvate. The cells subsequently send pyruvate to the mitochondria (the portion of the cell that generates energy) or convert pyruvate to another metabolite referred to as lactate.

The researchers blocked the generation of lactate in mice. This prevented the activation of hair follicle stem cells. The UCLA team worked with University of Utah Rutter lab academicians to boost lactate production in mice. This hastened the activation of hair follicle stem cells, causing an increase in the hair cycle. Prior to this, no one knew boosting or decreasing lactate would make an impact on hair follicle stem cells. Now that the researchers have determined how changing lactate production in mice changes hair growth, they can attempt to identify drugs that can be applied to the skin to produce the same effect.

Drugs of Note

The research groups identified a couple drugs that alter hair follicle stem cells in specific ways to boost lactate production when applied to mice skin. One of the drugs, RCGD423, triggers a cell signaling pathway referred to as JAK-Stat that transmits information from outside cells to the cell nucleus. Research shows JAK-Stat activation causes an increase in the generation of lactate. This spurs the activation of hair follicle stem cells and results in faster hair growth.

The second drug of note, UK5099, stops pyruvate from entering mitochondria. This forces the generation of lactate within the hair follicle stem cells, boosting the rate at which hair grows in mice. These experimental drugs were strictly used during pre-clinical testing. They have not been tested in human beings. Nor have these drugs been approved by the Food and Drug Administration as safe or effective for humans.

Why the Study Matters

This study is important as it provides plenty of insight into the many ways in which stem cells are activated. The idea of using drugs to catalyze hair growth by way of hair follicle stem cells is quite promising considering the millions of individuals who are bald or going bald. The researchers' findings will help improve the understanding of how metabolism affects hair growth as well as stem cells.