Therapy for Alopecia Areata in Mice by Stimulating the Hair Cycle with Parathyroid Hormone Agonists Linked to a Collagen-Binding Domain

Alopecia areata is a common disorder in which autoimmune destruction of hair follicles results in patchy hair loss. Currently there is no adequate therapy, although immune modulator therapies are currently in development. Parathyroid hormone (PTH) is a hair cycle stimulator which shows promise in treating various forms of alopecia, although its short half-life limits its clinical use. PTH-CBD is a PTH analog which binds collagen, prolonging retention in skin. We tested effects of PTH-CBD in C3H/HeJ-engrafted mice, the animal model for alopecia areata, on hair growth and found that a significant proportion of animals had reduced hair loss (PTH-CBD: 13/21, 62% vs. control: 3/10, 30%; P<0.01). Histological analysis showed no change in immune response, but there was increased number of anagen hair follicles and increased production of beta-catenin, a factor which initiates the anagen phase of the hair cycle. PTH-CBD thus shows promise as a therapy for alopecia areata, either alone or in conjunction with immune modulation therapy.