Janus kinase (JAK) inhibitors, used for treating auto-immune diseases such as rheumatoid arthritis, appear to strongly promote hair growth when applied topically to the skin, say researchers from Columbia University Medical Center in New York, NY.
The findings were published in Science Advances (Oct. 2, 2015; 1(9): e1500973). The researchers were testing JAK inhibitors orally for the treatment of alopecia areata. The drugs have also been tested for treating plaque psoriasis.
In a press release from the Medical Center on Oct. 23, 2015, study author Angela M. Christiano, PhD, said “What we’ve found is promising, though we haven’t yet shown it’s a cure for pattern baldness.”
“More work needs to be done to test if JAK inhibitors can induce hair growth in humans using formulations specially made for the scalp,” said Dr. Christiano.
Dr. Christiano and her team have been investigating the use of JAK inhibitors to impair the auto-immune attack on hair follicles associated with alopecia areata. In the course of those experiments, Dr. Christiano found that healthy mice grew more hair when the drugs were applied topically than when they were taken systemically. That suggested the drugs were doing more than just reducing the immune system’s attack on the hair follicles – they may be working on the hair follicles directly in some way, according to the release.
When the researchers looked closely, they found that JAK inhibitors applied directly were making the hair follicles come out of dormancy rapidly, with some resting hair follicles sprouting a new hair in less than 10 days.
“There aren’t many compounds that can push hair follicles into their growth cycle so quickly,” said Dr. Christiano in the release. “Some topical agents induce tufts of hair here and there after a few weeks, but very few compounds have this potent an effect so quickly.”
Normal human hair follicles grown in culture also grew longer when treated topically with JAK inhibitors.
Dr. Christiano and her team do not yet have data on using topical JAK inhibitors on hair follicles locked into a permanent rest state by male pattern baldness – androgenic alopecia – but experiments on hair follicles affected by hair loss disorders are underway, according to the release.