A quarter of the world’s population is affected by hair loss, whether due to age or autoimmune diseases such as alopecia. Promises of miracle cures have been multiplying for years but none have found the recipe for total regrowth. However, a Japanese team has just taken a more serious step, reports Popular Mechanics: it succeeded in growing fully functional hair follicles in the laboratory, then transplanting them into mice, where they followed a normal cycle of loss and regrowth for more than two months.
The work, published in the journal Biochemical and Biophysical Research Communications and carried out in part with the support of the company OrganTech, does not simply reformulate the usual hair transplant equation. Until now, attempts at regeneration have mainly relied on two types of cells: epithelial stem cells (which constitute the “sheath” of the follicle) and cells of the dermal papilla (which orchestrate its growth).
The researchers then added a third, long-neglected player: a particular type of mesenchymal cell, originating from an area of hairy skin, which plays a key role in the formation of the hair placode, this small thickening at the origin of every follicle.
Concretely, the team used a method developed for years to assemble a sort of bioengineered “follicle seed”: at the bottom, the dermal papilla cells; around, the supporting mesenchymal cells; at the top, the epithelial stem cells. Within two weeks, this mini-organ began to grow downward into an artificial skin model, forming a complete follicle and visible hair, with an architecture similar to that seen on your head.
A new approach
The challenge was not just to grow a hair in a Petri dish, but to know if this follicle could survive and function in a living organism. Transplanted into mouse skin, these reconstituted follicles integrated into the nervous and muscular network, produced a hair shaft and followed, over at least 68 days, a normal cycle of growth, shedding and regrowth. For the authors, this proves that a minimum configuration of three compartmentalized cell populations is sufficient to recreate a functional adult follicle, capable of entering the hair cycle.
This approach is radically different from current treatments, which mainly aim to slow down hair loss rather than rebuild lost hair units. OrganTech defends the idea of regenerative medicine at the organ level: rather than vaguely stimulating the scalp, it involves manufacturing “modules” of follicles from a well-defined cellular plan and implanting them where the hair has disappeared. Beyond hair, researchers see it as a model for certain other organs.
In the short term, these laboratory follicles offer above all a powerful tool for research. In the longer term, the team and OrganTech hope to translate this advance into treatments for alopecia, by combining collection of cells from the patient, expansion in culture and implantation of bioengineered follicles.
For the moment we are still at the stage of experimentation in mice, but for the first time, the prospect of “remanufacturing” lost hair is no longer just a matter of hair marketing.
