A new study out of Columbia has finally, after all these years, done it. That’s right, they’ve gotten nonproductive, cultured human dermal papillae to generate brand new dermal follicular cells. The group shifted culture conditions to allow for the dermal papillae to assume a 3D spheroid shape, rather than a 2D shape, which allows them to trigger de novo follicle growth in epidermal cells. They’ve grown hair. Follicles. Boom. Suck it middle age. We’re coming for you.
In rodents, these papillae can be moved from a hairy region to a hairless region and trigger new follicles to form no problem. But with humans, the transfer wasn’t so smooth. Normally, papillae reprogram epidermal cells to become follicular cells, thus generating new hair follicles (a process called folliculogenesis). But there seemed to be some loss of function when human papillae were cultured outside the body, resulting in a continued lack of hair. This group found that cultured papillae grown in a two dimensional environment changed function very quickly, with gene expression shifting dramatically and overall cellular function changing as a result. One of the first operations to go was follicle induction. So the group grew the papillae in 3D spheroid cultures, which was shown to restore hair follicle generation. New, functional follicles.
For some quick background, dermal papillae are small extensions found just below the outermost layer of skin. They connect the dermis and epidermis, where they serve to both support the epidermis and greatly increase the surface area of the interface between the two layers, thus strengthening their bond. They are also what make up your fingerprints, which is a pretty fun fact if you ask me. Relative to follicles though, the papillae that trigger formation are found at the base of the follicle itself (see diagram below).
According to the news release from Columbia itself, this new method promises to help a wide range of people for whom hair transplantation is not a viable option. As co-study leader Angela M. Christiano, PhD, says in the release, “This method offers the possibility of inducing large numbers of hair follicles or rejuvenating existing hair follicles, starting with cells grown from just a few hundred donor hairs. It could make hair transplantation available to individuals with a limited number of follicles, including those with female-pattern hair loss, scarring alopecia, and hair loss due to burns.”
Beyond allowing us to generate new hair follicles, this group’s results help us to better understand how organs can regenerate in general. For some species, organ regeneration is a common phenomenon, but not one that is always well understood and it is largely absent in humans. In this study though, researchers have demonstrated a means of induced organ regeneration for human cells through the body’s natural mechanisms. It may be small, but it’s a big idea and a huge step forward for regenerative medicine. So yeah, we can grow hair, but the real question is: what else can we grow?
Columbia news release (probably the best source here):
Original article (just an abstract, sorry):