The idea of baldness usually gets people thinking of aging men, even though hair loss affects all genders and ages. Hair loss can occur because of genetic predisposition, stress, drug side effects, or autoimmune disorders.
According to C&EN, two drugs that have been approved by the FDA, Ruxolitinib and Tofacitinib, have recently been tested and the results suggest that a treatment for all hair loss conditions may be on the way.
The team of researchers from Columbia University had observed that the drugs, which have been approved for the treatment of myelofibrosis and rheumatoid arthritis, respectively, actually promoted hair growth in mice, but they had also impaired the animals’ immune systems.
The scientists thought the compounds may work better if rubbed onto the rodents’ skin rather than administering it orally. They shaved the backs of the mice when their fur was in telogen, which is the resting stage of a hair follicle’s growth cycle.
When the fur is in the telogen stage, the hair will normally take over a month to start growing back. What they found was the areas of the mouse’s skin that was treated with Ruxolitinib or Tofacitinib grew back in less than three weeks.
Angela M. Christiano, the team leader, said the drugs were “basically accelerating what would normally happen several weeks later. They’re inducing new hair to begin to grow.”
The Columbia team then tested the compounds on human skin grafted onto mice with similar results, although tofacitinib proved to be significantly more effective.
The way these drugs work is very different to standard hair loss treatments like Rogaine, which is for pattern baldness men. Rogaine uses an active ingredient called minoxidil, a vasodilator, which stimulates blood flow to the hair follicles thus preventing the hair from falling out.
There are new treatments that inhibit JAK-STAT signalling, a pathway that involves Janus kinases, which trigger cells to begin transcribing DNA. The researchers believe this signalling pathway is most active when hair follicles are at rest.
When ruxolitinib and tofacitinib block the pathway, the follicles “activate” and enter a new growth phase.
Amy McMichael, a professor of dermatology at Wake Forest Baptist Medical Center, who was not involved in the study, told C&EN: “The big news of this new paper is that JAK inhibitors are even more versatile in function than previously thought.
“Not only do they have a burgeoning role in treating inflammatory conditions, but there appears to be a direct effect on stem cells that can impact hair growth function.”
The Columbia researchers are hopeful that the treatments may be useful in hair loss caused by alopecia areata, a disease that affects millions in the U.S., or even chemotherapy recipients.
“For any clinical setting where the hairs are stuck in resting phase,” Christiano says, “this would be a way to think about coaxing them back into the hair cycle.”