TLDR The upper dermal sheath can regenerate hair in rats.
The study from 1996 demonstrated that the upper dermal sheath of a rat vibrissa follicle had the potential to regenerate hair, contrary to previous beliefs. When the upper halves of the follicles were implanted under the kidney capsule for 8 weeks, pelage-type hairs were produced. Monoclonal antibody analysis revealed the formation of small hair bulbs due to interactions between upper dermal sheath cells and follicular basal cells. These new bulbs formed at the amputated end and upper region of the follicles, but not near the bulge area where stem cells are located. The study suggested that while the hair-inducing ability of the upper dermal sheath was weaker compared to lower dermal compartments, it was still sufficient to induce hair production under specific conditions.
745 citations,
February 1992 in “Trends in genetics” Hair follicles create different cell layers and proteins, controlled by various molecules.
68 citations,
December 1991 in “Annals of the New York Academy of Sciences” Hair growth can be induced by certain cells found at the base of hair follicles, and these cells may also influence hair development and regeneration.
January 2022 in “Journal of St. Marianna University” Substances from human hair cells can affect hair loss-related genes, potentially leading to new treatments for baldness.
15 citations,
April 2014 in “Experimental Dermatology” Scientists developed a system to study human hair growth using skin cells, which could help understand hair development and improve skin substitutes for medical use.
321 citations,
December 2009 in “Journal of Dermatological Science” Dermal cells are key in controlling hair growth and could potentially be used in hair loss treatments, but more research is needed to improve hair regeneration methods.
January 2003 in “Chinese Journal of Reparative and Reconstructive Surgery” Dermal papilla cells can help form hair follicles and produce hair.
66 citations,
August 2001 in “Experimental Dermatology” Human hair follicle cells can grow hair when put into mouse skin if they stay in contact with mouse cells.
57 citations,
November 1998 in “Wound Repair and Regeneration” Hair papilla cells can create and regenerate hair bulbs under the right conditions.