Role of hair papilla cells on induction and regeneration processes of hair follicles

The study "Role of hair papilla cells on induction and regeneration processes of hair follicles" from 1998 investigated the role of hair dermal papilla cells in hair formation, growth, and cycling. The researchers found that these specialized mesenchymal cells, located at the bottom of hair follicles, maintain their hair-forming activity even after long-term cultivation, especially when cultured with conditioned medium from keratinocytes or a medium containing fibroblast growth factor. The study also found that new hair matrix and papilla can regenerate from the rest of the follicle, even if the hair bulb has been removed. This regeneration does not occur when the lower half of a hair follicle is removed, but new hair bulbs were formed in the remaining upper halves of vibrissal follicles if the amputated follicles had been implanted under the kidney capsule. The study concluded that dermal papilla cells and probably dermal sheath cells have the ability to induce and form hair bulbs under preferred environmental conditions.