Hair Growth Biology

Hair growth is a uniquely mammalian trait, not shared by another other animal group. For humans, hair represents a powerful genetic and social signal. The hair follicle represents the only (mini-organ) tissue that undergoes life-long cycling, during which it recapitulates developmental and morphogenic stages.

Here in the Charles Institute we examine the cell biologic and molecular biologic events that regulate hair growth in healthy (including aging) and disease states e.g., androgenic alopecia (see also Inflammatory Skin Disease for Alopecia areata).

Alopecia areata  (Tobin Lab)

As social beings we communicate significantly via our physical appearance and so together with skin  pigmentation the hair fiber-producing mini-organ called the hair follicle accounts for most of the variation in the phenotype of different mammals and between different human population groupings.

Although commonly dismissed as being of superficial importance, the hair follicle(s) (HF) is truly one of human biology’s most fascinating structures. Hair growth, one of only two uniquely mammalian traits (in addition to mammary glands), serves several important functions. These include; thermal insulation, camouflage (melanin affords significant protective value), socialvand sexual communication, sensory perception (e.g., whiskers), and protection against trauma, noxious insults, insects, etc. These features have clearly facilitated evolutionary success in animals, but it is not immediately clear how these may have proved critical for human survival. That said, one should not diminish the role of hair in social and sexual communications among humans. Because of our relative nakedness most attention and study are focused on scalp hair that, uniquely amongst primates, can be very thick, very long and very pigmented. Conversely, its absence from the human scalp can result in significant psychological trauma (e.g., in cases of androgenetic alopecia, alopecia areata, and chemotherapy-induced alopecia).  This increasing attention to hair-care is reflected in the unremitting growth of the hair-care market, already a multi-billion euro enterprise world-wide.

At present, our research is focussing on the relatively common immune-mediated disorder alopecia areata, especially from the perspective of autoantigen identification, and on the regulation of hair pigmentation. Our hair follicle research here in the Charles Institute of Dermatology is conducted in partnership with clinical and medical colleagues (e.g., at Dublin’s HRBR - Hair Restoration Blackrock) as well as with scientists (inter)nationally.