Scientists at Harvard have developed a promising new treatment to reverse hair loss associated with alopecia. Painless microneedle patches loaded with an immune regulating drug regrew hair in mice with alopecia within a few weeks.
Unlike other forms of hair loss, alopecia areata is an autoimmune disease. For reasons that are unclear, T cells mistakenly begin attacking the follicles, causing hair to fall out in patches. Some patients will experience single episodes with their hair later regrowing, while others will have intermittent hair loss throughout their lives, and for some it’s permanent.
Intriguingly, hair regrowth has been a side effect of alopecia patients receiving immune-suppressing drugs for other conditions, like eczema and arthritis. But these, along with other drugs that treat alopecia by suppressing the immune system, only seem to have temporary benefits – as soon as the treatment is stopped, the hair falls out again. This could be because the drug isn’t just targeting the T cells that attack the follicles, but also the regulatory T cells (T-regs) that keep them in check. Plus, suppressing the immune system leaves patients open to infections.
So for the new study, the researchers investigated how to increase levels of T-regs without suppressing other immune cells. The team combined two components that help that goal into one drug: CCL22, which chemically attracts T-regs to a site, and IL-2, which amplifies them. These were then loaded into a microneedle patch that can be applied to the affected area.
As the name suggests, microneedle patches are made of tiny needles that deliver a drug directly into the skin. Because they can reach deeper than a topical cream, they’re more effective, but because they don’t reach deep enough to hit the pain receptors, they’re also painless.
The researchers tested the treatment in mouse models of alopecia, applying the patches 10 times over three weeks then watching them for a further eight weeks. Hair began to regrow in as little as three weeks, and was sustained over the observation period. Inflammatory pathways were also found to be attenuated.
To make sure the improvement wasn’t just down to the delivery method, the researchers also tested loading the microneedle patches with baricitinib, an FDA-approved alopecia drug. That, however, didn’t perform as well as the new IL-2/CCL22 patch.
“Our strategy tackles two major challenges in treating autoimmune skin diseases,” said Natalie Artzi, co-corresponding author of the study. “Our patches enable local delivery of biologics, which, instead of suppressing the immune system, promote regulatory T cells in the skin. This restores immune balance and resolves the T cell attack on hair follicles, offering a potential long-term solution without compromising the immune system’s ability to defend against infections and malignancies.”
As an added bonus, the microneedle patches have a good shelf-life stability, making them better suited for clinical use. The team says that they could also be investigated to treat other autoimmune skin diseases like vitiligo and psoriasis. Further development and testing is ongoing.
The research was published in the journal Advanced Materials.
Source: Harvard
