CROSS REFERENCE TO RELATED APPLICATIONS This non-provisional application claims priority from U.S. provisional application US 61/353,272 filed on Jun. 10, 2010, which is incorporated herein by reference in its entirety.
The application relates to compositions and methods for generating hair follicles. In particular, the application relates to implanting in vitro-cultivated hair follicle cells into a scalp to generate and rejuvenate hair follicles in a subject suffering from hair loss.
Hair loss affects millions of people, including over 40% of men over the age of 30. Numerous factors can cause hair loss, including genetic predisposition, autoimmune reactions, scarring, diseases and infection. Hair loss can ultimately lead to complete baldness.
Alopecia is a medical condition in which hair is lost from an area of the body. One symptom of alopecia is hair follicle miniaturization (described below). Alopecia includes both androgenetic alopecia, also known as male pattern baldness, and alopecia areata, which is thought to be an autoimmune disorder.
Normally, a hair follicle cycles through phases including the anagen (growth) phase, the catagen (transition) phase and the telogen (resting or quiescent) phase. In the miniaturization process, the hair follicle enters a prolonged lag phase following the telogen stage. With successive anagen cycles, the follicles become smaller, leading to shorter, finer hair. The miniaturized follicle eventually produces a tiny hair shaft that is cosmetically insignificant. Ultimately, the follicle can stop producing a hair shaft altogether and the area of hair loss can become completely devoid of hair.
Several methods for treating hair loss are available, including drugs such as topical minoxidil and orally-delivered propecia. However, these treatments have achieved limited success in restoring natural hair growth and are only effective while the drugs are being taken.
One surgical treatment for hair loss is hair follicle transplantation, a procedure in which hair follicles are transplanted from a non-balding region of the scalp to a region of hair loss.
Alternatives to hair follicle transplantation are cell-based therapies whereby cells are implanted with the goal of developing new hair follicles. For example, U.S. Pat. No. 4,919,664 to Oliver et al. relates to a method of stimulating hair growth in the skin of a mammal by culturing at least one lower follicular dermal cell, and implanting the cultured cells in the epidermis. U.S. Pat. No. 6,399,057 to Gho describes a method of regenerating hair by: (1) removing hair in the anagen phase, (2) culturing hair follicle cells, and (3) implanting the cultured cells into bald regions. In addition, U.S. Patent Application No. 2007/0128172 to Yoshizato et al. describes the transplantation of cultured dermal papilla cells, dermal sheath cells and epidermal cells into the skin to regenerate hair. In Wu et al. (2006), cultured dermal papilla cells were mixed with outer root sheath cells and transplanted on the dorsal skin of nude mice to induce hair follicle and hair fiber formation.
There remains a need for efficient, cell-based therapies for rejuvenating miniaturized hair follicles and generating new hair follicles.